xref: /openbmc/linux/kernel/bpf/verifier.c (revision 00d0f31a)
1 // SPDX-License-Identifier: GPL-2.0-only
2 /* Copyright (c) 2011-2014 PLUMgrid, http://plumgrid.com
3  * Copyright (c) 2016 Facebook
4  * Copyright (c) 2018 Covalent IO, Inc. http://covalent.io
5  */
6 #include <uapi/linux/btf.h>
7 #include <linux/bpf-cgroup.h>
8 #include <linux/kernel.h>
9 #include <linux/types.h>
10 #include <linux/slab.h>
11 #include <linux/bpf.h>
12 #include <linux/btf.h>
13 #include <linux/bpf_verifier.h>
14 #include <linux/filter.h>
15 #include <net/netlink.h>
16 #include <linux/file.h>
17 #include <linux/vmalloc.h>
18 #include <linux/stringify.h>
19 #include <linux/bsearch.h>
20 #include <linux/sort.h>
21 #include <linux/perf_event.h>
22 #include <linux/ctype.h>
23 #include <linux/error-injection.h>
24 #include <linux/bpf_lsm.h>
25 #include <linux/btf_ids.h>
26 #include <linux/poison.h>
27 #include <linux/module.h>
28 
29 #include "disasm.h"
30 
31 static const struct bpf_verifier_ops * const bpf_verifier_ops[] = {
32 #define BPF_PROG_TYPE(_id, _name, prog_ctx_type, kern_ctx_type) \
33 	[_id] = & _name ## _verifier_ops,
34 #define BPF_MAP_TYPE(_id, _ops)
35 #define BPF_LINK_TYPE(_id, _name)
36 #include <linux/bpf_types.h>
37 #undef BPF_PROG_TYPE
38 #undef BPF_MAP_TYPE
39 #undef BPF_LINK_TYPE
40 };
41 
42 /* bpf_check() is a static code analyzer that walks eBPF program
43  * instruction by instruction and updates register/stack state.
44  * All paths of conditional branches are analyzed until 'bpf_exit' insn.
45  *
46  * The first pass is depth-first-search to check that the program is a DAG.
47  * It rejects the following programs:
48  * - larger than BPF_MAXINSNS insns
49  * - if loop is present (detected via back-edge)
50  * - unreachable insns exist (shouldn't be a forest. program = one function)
51  * - out of bounds or malformed jumps
52  * The second pass is all possible path descent from the 1st insn.
53  * Since it's analyzing all paths through the program, the length of the
54  * analysis is limited to 64k insn, which may be hit even if total number of
55  * insn is less then 4K, but there are too many branches that change stack/regs.
56  * Number of 'branches to be analyzed' is limited to 1k
57  *
58  * On entry to each instruction, each register has a type, and the instruction
59  * changes the types of the registers depending on instruction semantics.
60  * If instruction is BPF_MOV64_REG(BPF_REG_1, BPF_REG_5), then type of R5 is
61  * copied to R1.
62  *
63  * All registers are 64-bit.
64  * R0 - return register
65  * R1-R5 argument passing registers
66  * R6-R9 callee saved registers
67  * R10 - frame pointer read-only
68  *
69  * At the start of BPF program the register R1 contains a pointer to bpf_context
70  * and has type PTR_TO_CTX.
71  *
72  * Verifier tracks arithmetic operations on pointers in case:
73  *    BPF_MOV64_REG(BPF_REG_1, BPF_REG_10),
74  *    BPF_ALU64_IMM(BPF_ADD, BPF_REG_1, -20),
75  * 1st insn copies R10 (which has FRAME_PTR) type into R1
76  * and 2nd arithmetic instruction is pattern matched to recognize
77  * that it wants to construct a pointer to some element within stack.
78  * So after 2nd insn, the register R1 has type PTR_TO_STACK
79  * (and -20 constant is saved for further stack bounds checking).
80  * Meaning that this reg is a pointer to stack plus known immediate constant.
81  *
82  * Most of the time the registers have SCALAR_VALUE type, which
83  * means the register has some value, but it's not a valid pointer.
84  * (like pointer plus pointer becomes SCALAR_VALUE type)
85  *
86  * When verifier sees load or store instructions the type of base register
87  * can be: PTR_TO_MAP_VALUE, PTR_TO_CTX, PTR_TO_STACK, PTR_TO_SOCKET. These are
88  * four pointer types recognized by check_mem_access() function.
89  *
90  * PTR_TO_MAP_VALUE means that this register is pointing to 'map element value'
91  * and the range of [ptr, ptr + map's value_size) is accessible.
92  *
93  * registers used to pass values to function calls are checked against
94  * function argument constraints.
95  *
96  * ARG_PTR_TO_MAP_KEY is one of such argument constraints.
97  * It means that the register type passed to this function must be
98  * PTR_TO_STACK and it will be used inside the function as
99  * 'pointer to map element key'
100  *
101  * For example the argument constraints for bpf_map_lookup_elem():
102  *   .ret_type = RET_PTR_TO_MAP_VALUE_OR_NULL,
103  *   .arg1_type = ARG_CONST_MAP_PTR,
104  *   .arg2_type = ARG_PTR_TO_MAP_KEY,
105  *
106  * ret_type says that this function returns 'pointer to map elem value or null'
107  * function expects 1st argument to be a const pointer to 'struct bpf_map' and
108  * 2nd argument should be a pointer to stack, which will be used inside
109  * the helper function as a pointer to map element key.
110  *
111  * On the kernel side the helper function looks like:
112  * u64 bpf_map_lookup_elem(u64 r1, u64 r2, u64 r3, u64 r4, u64 r5)
113  * {
114  *    struct bpf_map *map = (struct bpf_map *) (unsigned long) r1;
115  *    void *key = (void *) (unsigned long) r2;
116  *    void *value;
117  *
118  *    here kernel can access 'key' and 'map' pointers safely, knowing that
119  *    [key, key + map->key_size) bytes are valid and were initialized on
120  *    the stack of eBPF program.
121  * }
122  *
123  * Corresponding eBPF program may look like:
124  *    BPF_MOV64_REG(BPF_REG_2, BPF_REG_10),  // after this insn R2 type is FRAME_PTR
125  *    BPF_ALU64_IMM(BPF_ADD, BPF_REG_2, -4), // after this insn R2 type is PTR_TO_STACK
126  *    BPF_LD_MAP_FD(BPF_REG_1, map_fd),      // after this insn R1 type is CONST_PTR_TO_MAP
127  *    BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, 0, 0, BPF_FUNC_map_lookup_elem),
128  * here verifier looks at prototype of map_lookup_elem() and sees:
129  * .arg1_type == ARG_CONST_MAP_PTR and R1->type == CONST_PTR_TO_MAP, which is ok,
130  * Now verifier knows that this map has key of R1->map_ptr->key_size bytes
131  *
132  * Then .arg2_type == ARG_PTR_TO_MAP_KEY and R2->type == PTR_TO_STACK, ok so far,
133  * Now verifier checks that [R2, R2 + map's key_size) are within stack limits
134  * and were initialized prior to this call.
135  * If it's ok, then verifier allows this BPF_CALL insn and looks at
136  * .ret_type which is RET_PTR_TO_MAP_VALUE_OR_NULL, so it sets
137  * R0->type = PTR_TO_MAP_VALUE_OR_NULL which means bpf_map_lookup_elem() function
138  * returns either pointer to map value or NULL.
139  *
140  * When type PTR_TO_MAP_VALUE_OR_NULL passes through 'if (reg != 0) goto +off'
141  * insn, the register holding that pointer in the true branch changes state to
142  * PTR_TO_MAP_VALUE and the same register changes state to CONST_IMM in the false
143  * branch. See check_cond_jmp_op().
144  *
145  * After the call R0 is set to return type of the function and registers R1-R5
146  * are set to NOT_INIT to indicate that they are no longer readable.
147  *
148  * The following reference types represent a potential reference to a kernel
149  * resource which, after first being allocated, must be checked and freed by
150  * the BPF program:
151  * - PTR_TO_SOCKET_OR_NULL, PTR_TO_SOCKET
152  *
153  * When the verifier sees a helper call return a reference type, it allocates a
154  * pointer id for the reference and stores it in the current function state.
155  * Similar to the way that PTR_TO_MAP_VALUE_OR_NULL is converted into
156  * PTR_TO_MAP_VALUE, PTR_TO_SOCKET_OR_NULL becomes PTR_TO_SOCKET when the type
157  * passes through a NULL-check conditional. For the branch wherein the state is
158  * changed to CONST_IMM, the verifier releases the reference.
159  *
160  * For each helper function that allocates a reference, such as
161  * bpf_sk_lookup_tcp(), there is a corresponding release function, such as
162  * bpf_sk_release(). When a reference type passes into the release function,
163  * the verifier also releases the reference. If any unchecked or unreleased
164  * reference remains at the end of the program, the verifier rejects it.
165  */
166 
167 /* verifier_state + insn_idx are pushed to stack when branch is encountered */
168 struct bpf_verifier_stack_elem {
169 	/* verifer state is 'st'
170 	 * before processing instruction 'insn_idx'
171 	 * and after processing instruction 'prev_insn_idx'
172 	 */
173 	struct bpf_verifier_state st;
174 	int insn_idx;
175 	int prev_insn_idx;
176 	struct bpf_verifier_stack_elem *next;
177 	/* length of verifier log at the time this state was pushed on stack */
178 	u32 log_pos;
179 };
180 
181 #define BPF_COMPLEXITY_LIMIT_JMP_SEQ	8192
182 #define BPF_COMPLEXITY_LIMIT_STATES	64
183 
184 #define BPF_MAP_KEY_POISON	(1ULL << 63)
185 #define BPF_MAP_KEY_SEEN	(1ULL << 62)
186 
187 #define BPF_MAP_PTR_UNPRIV	1UL
188 #define BPF_MAP_PTR_POISON	((void *)((0xeB9FUL << 1) +	\
189 					  POISON_POINTER_DELTA))
190 #define BPF_MAP_PTR(X)		((struct bpf_map *)((X) & ~BPF_MAP_PTR_UNPRIV))
191 
192 static int acquire_reference_state(struct bpf_verifier_env *env, int insn_idx);
193 static int release_reference(struct bpf_verifier_env *env, int ref_obj_id);
194 static void invalidate_non_owning_refs(struct bpf_verifier_env *env);
195 static bool in_rbtree_lock_required_cb(struct bpf_verifier_env *env);
196 static int ref_set_non_owning(struct bpf_verifier_env *env,
197 			      struct bpf_reg_state *reg);
198 static void specialize_kfunc(struct bpf_verifier_env *env,
199 			     u32 func_id, u16 offset, unsigned long *addr);
200 
201 static bool bpf_map_ptr_poisoned(const struct bpf_insn_aux_data *aux)
202 {
203 	return BPF_MAP_PTR(aux->map_ptr_state) == BPF_MAP_PTR_POISON;
204 }
205 
206 static bool bpf_map_ptr_unpriv(const struct bpf_insn_aux_data *aux)
207 {
208 	return aux->map_ptr_state & BPF_MAP_PTR_UNPRIV;
209 }
210 
211 static void bpf_map_ptr_store(struct bpf_insn_aux_data *aux,
212 			      const struct bpf_map *map, bool unpriv)
213 {
214 	BUILD_BUG_ON((unsigned long)BPF_MAP_PTR_POISON & BPF_MAP_PTR_UNPRIV);
215 	unpriv |= bpf_map_ptr_unpriv(aux);
216 	aux->map_ptr_state = (unsigned long)map |
217 			     (unpriv ? BPF_MAP_PTR_UNPRIV : 0UL);
218 }
219 
220 static bool bpf_map_key_poisoned(const struct bpf_insn_aux_data *aux)
221 {
222 	return aux->map_key_state & BPF_MAP_KEY_POISON;
223 }
224 
225 static bool bpf_map_key_unseen(const struct bpf_insn_aux_data *aux)
226 {
227 	return !(aux->map_key_state & BPF_MAP_KEY_SEEN);
228 }
229 
230 static u64 bpf_map_key_immediate(const struct bpf_insn_aux_data *aux)
231 {
232 	return aux->map_key_state & ~(BPF_MAP_KEY_SEEN | BPF_MAP_KEY_POISON);
233 }
234 
235 static void bpf_map_key_store(struct bpf_insn_aux_data *aux, u64 state)
236 {
237 	bool poisoned = bpf_map_key_poisoned(aux);
238 
239 	aux->map_key_state = state | BPF_MAP_KEY_SEEN |
240 			     (poisoned ? BPF_MAP_KEY_POISON : 0ULL);
241 }
242 
243 static bool bpf_pseudo_call(const struct bpf_insn *insn)
244 {
245 	return insn->code == (BPF_JMP | BPF_CALL) &&
246 	       insn->src_reg == BPF_PSEUDO_CALL;
247 }
248 
249 static bool bpf_pseudo_kfunc_call(const struct bpf_insn *insn)
250 {
251 	return insn->code == (BPF_JMP | BPF_CALL) &&
252 	       insn->src_reg == BPF_PSEUDO_KFUNC_CALL;
253 }
254 
255 struct bpf_call_arg_meta {
256 	struct bpf_map *map_ptr;
257 	bool raw_mode;
258 	bool pkt_access;
259 	u8 release_regno;
260 	int regno;
261 	int access_size;
262 	int mem_size;
263 	u64 msize_max_value;
264 	int ref_obj_id;
265 	int dynptr_id;
266 	int map_uid;
267 	int func_id;
268 	struct btf *btf;
269 	u32 btf_id;
270 	struct btf *ret_btf;
271 	u32 ret_btf_id;
272 	u32 subprogno;
273 	struct btf_field *kptr_field;
274 };
275 
276 struct btf_and_id {
277 	struct btf *btf;
278 	u32 btf_id;
279 };
280 
281 struct bpf_kfunc_call_arg_meta {
282 	/* In parameters */
283 	struct btf *btf;
284 	u32 func_id;
285 	u32 kfunc_flags;
286 	const struct btf_type *func_proto;
287 	const char *func_name;
288 	/* Out parameters */
289 	u32 ref_obj_id;
290 	u8 release_regno;
291 	bool r0_rdonly;
292 	u32 ret_btf_id;
293 	u64 r0_size;
294 	u32 subprogno;
295 	struct {
296 		u64 value;
297 		bool found;
298 	} arg_constant;
299 	union {
300 		struct btf_and_id arg_obj_drop;
301 		struct btf_and_id arg_refcount_acquire;
302 	};
303 	struct {
304 		struct btf_field *field;
305 	} arg_list_head;
306 	struct {
307 		struct btf_field *field;
308 	} arg_rbtree_root;
309 	struct {
310 		enum bpf_dynptr_type type;
311 		u32 id;
312 	} initialized_dynptr;
313 	struct {
314 		u8 spi;
315 		u8 frameno;
316 	} iter;
317 	u64 mem_size;
318 };
319 
320 struct btf *btf_vmlinux;
321 
322 static DEFINE_MUTEX(bpf_verifier_lock);
323 
324 static const struct bpf_line_info *
325 find_linfo(const struct bpf_verifier_env *env, u32 insn_off)
326 {
327 	const struct bpf_line_info *linfo;
328 	const struct bpf_prog *prog;
329 	u32 i, nr_linfo;
330 
331 	prog = env->prog;
332 	nr_linfo = prog->aux->nr_linfo;
333 
334 	if (!nr_linfo || insn_off >= prog->len)
335 		return NULL;
336 
337 	linfo = prog->aux->linfo;
338 	for (i = 1; i < nr_linfo; i++)
339 		if (insn_off < linfo[i].insn_off)
340 			break;
341 
342 	return &linfo[i - 1];
343 }
344 
345 __printf(2, 3) static void verbose(void *private_data, const char *fmt, ...)
346 {
347 	struct bpf_verifier_env *env = private_data;
348 	va_list args;
349 
350 	if (!bpf_verifier_log_needed(&env->log))
351 		return;
352 
353 	va_start(args, fmt);
354 	bpf_verifier_vlog(&env->log, fmt, args);
355 	va_end(args);
356 }
357 
358 static const char *ltrim(const char *s)
359 {
360 	while (isspace(*s))
361 		s++;
362 
363 	return s;
364 }
365 
366 __printf(3, 4) static void verbose_linfo(struct bpf_verifier_env *env,
367 					 u32 insn_off,
368 					 const char *prefix_fmt, ...)
369 {
370 	const struct bpf_line_info *linfo;
371 
372 	if (!bpf_verifier_log_needed(&env->log))
373 		return;
374 
375 	linfo = find_linfo(env, insn_off);
376 	if (!linfo || linfo == env->prev_linfo)
377 		return;
378 
379 	if (prefix_fmt) {
380 		va_list args;
381 
382 		va_start(args, prefix_fmt);
383 		bpf_verifier_vlog(&env->log, prefix_fmt, args);
384 		va_end(args);
385 	}
386 
387 	verbose(env, "%s\n",
388 		ltrim(btf_name_by_offset(env->prog->aux->btf,
389 					 linfo->line_off)));
390 
391 	env->prev_linfo = linfo;
392 }
393 
394 static void verbose_invalid_scalar(struct bpf_verifier_env *env,
395 				   struct bpf_reg_state *reg,
396 				   struct tnum *range, const char *ctx,
397 				   const char *reg_name)
398 {
399 	char tn_buf[48];
400 
401 	verbose(env, "At %s the register %s ", ctx, reg_name);
402 	if (!tnum_is_unknown(reg->var_off)) {
403 		tnum_strn(tn_buf, sizeof(tn_buf), reg->var_off);
404 		verbose(env, "has value %s", tn_buf);
405 	} else {
406 		verbose(env, "has unknown scalar value");
407 	}
408 	tnum_strn(tn_buf, sizeof(tn_buf), *range);
409 	verbose(env, " should have been in %s\n", tn_buf);
410 }
411 
412 static bool type_is_pkt_pointer(enum bpf_reg_type type)
413 {
414 	type = base_type(type);
415 	return type == PTR_TO_PACKET ||
416 	       type == PTR_TO_PACKET_META;
417 }
418 
419 static bool type_is_sk_pointer(enum bpf_reg_type type)
420 {
421 	return type == PTR_TO_SOCKET ||
422 		type == PTR_TO_SOCK_COMMON ||
423 		type == PTR_TO_TCP_SOCK ||
424 		type == PTR_TO_XDP_SOCK;
425 }
426 
427 static bool type_may_be_null(u32 type)
428 {
429 	return type & PTR_MAYBE_NULL;
430 }
431 
432 static bool reg_type_not_null(enum bpf_reg_type type)
433 {
434 	if (type_may_be_null(type))
435 		return false;
436 
437 	type = base_type(type);
438 	return type == PTR_TO_SOCKET ||
439 		type == PTR_TO_TCP_SOCK ||
440 		type == PTR_TO_MAP_VALUE ||
441 		type == PTR_TO_MAP_KEY ||
442 		type == PTR_TO_SOCK_COMMON ||
443 		type == PTR_TO_MEM;
444 }
445 
446 static bool type_is_ptr_alloc_obj(u32 type)
447 {
448 	return base_type(type) == PTR_TO_BTF_ID && type_flag(type) & MEM_ALLOC;
449 }
450 
451 static bool type_is_non_owning_ref(u32 type)
452 {
453 	return type_is_ptr_alloc_obj(type) && type_flag(type) & NON_OWN_REF;
454 }
455 
456 static struct btf_record *reg_btf_record(const struct bpf_reg_state *reg)
457 {
458 	struct btf_record *rec = NULL;
459 	struct btf_struct_meta *meta;
460 
461 	if (reg->type == PTR_TO_MAP_VALUE) {
462 		rec = reg->map_ptr->record;
463 	} else if (type_is_ptr_alloc_obj(reg->type)) {
464 		meta = btf_find_struct_meta(reg->btf, reg->btf_id);
465 		if (meta)
466 			rec = meta->record;
467 	}
468 	return rec;
469 }
470 
471 static bool reg_may_point_to_spin_lock(const struct bpf_reg_state *reg)
472 {
473 	return btf_record_has_field(reg_btf_record(reg), BPF_SPIN_LOCK);
474 }
475 
476 static bool type_is_rdonly_mem(u32 type)
477 {
478 	return type & MEM_RDONLY;
479 }
480 
481 static bool is_acquire_function(enum bpf_func_id func_id,
482 				const struct bpf_map *map)
483 {
484 	enum bpf_map_type map_type = map ? map->map_type : BPF_MAP_TYPE_UNSPEC;
485 
486 	if (func_id == BPF_FUNC_sk_lookup_tcp ||
487 	    func_id == BPF_FUNC_sk_lookup_udp ||
488 	    func_id == BPF_FUNC_skc_lookup_tcp ||
489 	    func_id == BPF_FUNC_ringbuf_reserve ||
490 	    func_id == BPF_FUNC_kptr_xchg)
491 		return true;
492 
493 	if (func_id == BPF_FUNC_map_lookup_elem &&
494 	    (map_type == BPF_MAP_TYPE_SOCKMAP ||
495 	     map_type == BPF_MAP_TYPE_SOCKHASH))
496 		return true;
497 
498 	return false;
499 }
500 
501 static bool is_ptr_cast_function(enum bpf_func_id func_id)
502 {
503 	return func_id == BPF_FUNC_tcp_sock ||
504 		func_id == BPF_FUNC_sk_fullsock ||
505 		func_id == BPF_FUNC_skc_to_tcp_sock ||
506 		func_id == BPF_FUNC_skc_to_tcp6_sock ||
507 		func_id == BPF_FUNC_skc_to_udp6_sock ||
508 		func_id == BPF_FUNC_skc_to_mptcp_sock ||
509 		func_id == BPF_FUNC_skc_to_tcp_timewait_sock ||
510 		func_id == BPF_FUNC_skc_to_tcp_request_sock;
511 }
512 
513 static bool is_dynptr_ref_function(enum bpf_func_id func_id)
514 {
515 	return func_id == BPF_FUNC_dynptr_data;
516 }
517 
518 static bool is_callback_calling_function(enum bpf_func_id func_id)
519 {
520 	return func_id == BPF_FUNC_for_each_map_elem ||
521 	       func_id == BPF_FUNC_timer_set_callback ||
522 	       func_id == BPF_FUNC_find_vma ||
523 	       func_id == BPF_FUNC_loop ||
524 	       func_id == BPF_FUNC_user_ringbuf_drain;
525 }
526 
527 static bool is_storage_get_function(enum bpf_func_id func_id)
528 {
529 	return func_id == BPF_FUNC_sk_storage_get ||
530 	       func_id == BPF_FUNC_inode_storage_get ||
531 	       func_id == BPF_FUNC_task_storage_get ||
532 	       func_id == BPF_FUNC_cgrp_storage_get;
533 }
534 
535 static bool helper_multiple_ref_obj_use(enum bpf_func_id func_id,
536 					const struct bpf_map *map)
537 {
538 	int ref_obj_uses = 0;
539 
540 	if (is_ptr_cast_function(func_id))
541 		ref_obj_uses++;
542 	if (is_acquire_function(func_id, map))
543 		ref_obj_uses++;
544 	if (is_dynptr_ref_function(func_id))
545 		ref_obj_uses++;
546 
547 	return ref_obj_uses > 1;
548 }
549 
550 static bool is_cmpxchg_insn(const struct bpf_insn *insn)
551 {
552 	return BPF_CLASS(insn->code) == BPF_STX &&
553 	       BPF_MODE(insn->code) == BPF_ATOMIC &&
554 	       insn->imm == BPF_CMPXCHG;
555 }
556 
557 /* string representation of 'enum bpf_reg_type'
558  *
559  * Note that reg_type_str() can not appear more than once in a single verbose()
560  * statement.
561  */
562 static const char *reg_type_str(struct bpf_verifier_env *env,
563 				enum bpf_reg_type type)
564 {
565 	char postfix[16] = {0}, prefix[64] = {0};
566 	static const char * const str[] = {
567 		[NOT_INIT]		= "?",
568 		[SCALAR_VALUE]		= "scalar",
569 		[PTR_TO_CTX]		= "ctx",
570 		[CONST_PTR_TO_MAP]	= "map_ptr",
571 		[PTR_TO_MAP_VALUE]	= "map_value",
572 		[PTR_TO_STACK]		= "fp",
573 		[PTR_TO_PACKET]		= "pkt",
574 		[PTR_TO_PACKET_META]	= "pkt_meta",
575 		[PTR_TO_PACKET_END]	= "pkt_end",
576 		[PTR_TO_FLOW_KEYS]	= "flow_keys",
577 		[PTR_TO_SOCKET]		= "sock",
578 		[PTR_TO_SOCK_COMMON]	= "sock_common",
579 		[PTR_TO_TCP_SOCK]	= "tcp_sock",
580 		[PTR_TO_TP_BUFFER]	= "tp_buffer",
581 		[PTR_TO_XDP_SOCK]	= "xdp_sock",
582 		[PTR_TO_BTF_ID]		= "ptr_",
583 		[PTR_TO_MEM]		= "mem",
584 		[PTR_TO_BUF]		= "buf",
585 		[PTR_TO_FUNC]		= "func",
586 		[PTR_TO_MAP_KEY]	= "map_key",
587 		[CONST_PTR_TO_DYNPTR]	= "dynptr_ptr",
588 	};
589 
590 	if (type & PTR_MAYBE_NULL) {
591 		if (base_type(type) == PTR_TO_BTF_ID)
592 			strncpy(postfix, "or_null_", 16);
593 		else
594 			strncpy(postfix, "_or_null", 16);
595 	}
596 
597 	snprintf(prefix, sizeof(prefix), "%s%s%s%s%s%s%s",
598 		 type & MEM_RDONLY ? "rdonly_" : "",
599 		 type & MEM_RINGBUF ? "ringbuf_" : "",
600 		 type & MEM_USER ? "user_" : "",
601 		 type & MEM_PERCPU ? "percpu_" : "",
602 		 type & MEM_RCU ? "rcu_" : "",
603 		 type & PTR_UNTRUSTED ? "untrusted_" : "",
604 		 type & PTR_TRUSTED ? "trusted_" : ""
605 	);
606 
607 	snprintf(env->type_str_buf, TYPE_STR_BUF_LEN, "%s%s%s",
608 		 prefix, str[base_type(type)], postfix);
609 	return env->type_str_buf;
610 }
611 
612 static char slot_type_char[] = {
613 	[STACK_INVALID]	= '?',
614 	[STACK_SPILL]	= 'r',
615 	[STACK_MISC]	= 'm',
616 	[STACK_ZERO]	= '0',
617 	[STACK_DYNPTR]	= 'd',
618 	[STACK_ITER]	= 'i',
619 };
620 
621 static void print_liveness(struct bpf_verifier_env *env,
622 			   enum bpf_reg_liveness live)
623 {
624 	if (live & (REG_LIVE_READ | REG_LIVE_WRITTEN | REG_LIVE_DONE))
625 	    verbose(env, "_");
626 	if (live & REG_LIVE_READ)
627 		verbose(env, "r");
628 	if (live & REG_LIVE_WRITTEN)
629 		verbose(env, "w");
630 	if (live & REG_LIVE_DONE)
631 		verbose(env, "D");
632 }
633 
634 static int __get_spi(s32 off)
635 {
636 	return (-off - 1) / BPF_REG_SIZE;
637 }
638 
639 static struct bpf_func_state *func(struct bpf_verifier_env *env,
640 				   const struct bpf_reg_state *reg)
641 {
642 	struct bpf_verifier_state *cur = env->cur_state;
643 
644 	return cur->frame[reg->frameno];
645 }
646 
647 static bool is_spi_bounds_valid(struct bpf_func_state *state, int spi, int nr_slots)
648 {
649        int allocated_slots = state->allocated_stack / BPF_REG_SIZE;
650 
651        /* We need to check that slots between [spi - nr_slots + 1, spi] are
652 	* within [0, allocated_stack).
653 	*
654 	* Please note that the spi grows downwards. For example, a dynptr
655 	* takes the size of two stack slots; the first slot will be at
656 	* spi and the second slot will be at spi - 1.
657 	*/
658        return spi - nr_slots + 1 >= 0 && spi < allocated_slots;
659 }
660 
661 static int stack_slot_obj_get_spi(struct bpf_verifier_env *env, struct bpf_reg_state *reg,
662 			          const char *obj_kind, int nr_slots)
663 {
664 	int off, spi;
665 
666 	if (!tnum_is_const(reg->var_off)) {
667 		verbose(env, "%s has to be at a constant offset\n", obj_kind);
668 		return -EINVAL;
669 	}
670 
671 	off = reg->off + reg->var_off.value;
672 	if (off % BPF_REG_SIZE) {
673 		verbose(env, "cannot pass in %s at an offset=%d\n", obj_kind, off);
674 		return -EINVAL;
675 	}
676 
677 	spi = __get_spi(off);
678 	if (spi + 1 < nr_slots) {
679 		verbose(env, "cannot pass in %s at an offset=%d\n", obj_kind, off);
680 		return -EINVAL;
681 	}
682 
683 	if (!is_spi_bounds_valid(func(env, reg), spi, nr_slots))
684 		return -ERANGE;
685 	return spi;
686 }
687 
688 static int dynptr_get_spi(struct bpf_verifier_env *env, struct bpf_reg_state *reg)
689 {
690 	return stack_slot_obj_get_spi(env, reg, "dynptr", BPF_DYNPTR_NR_SLOTS);
691 }
692 
693 static int iter_get_spi(struct bpf_verifier_env *env, struct bpf_reg_state *reg, int nr_slots)
694 {
695 	return stack_slot_obj_get_spi(env, reg, "iter", nr_slots);
696 }
697 
698 static const char *btf_type_name(const struct btf *btf, u32 id)
699 {
700 	return btf_name_by_offset(btf, btf_type_by_id(btf, id)->name_off);
701 }
702 
703 static const char *dynptr_type_str(enum bpf_dynptr_type type)
704 {
705 	switch (type) {
706 	case BPF_DYNPTR_TYPE_LOCAL:
707 		return "local";
708 	case BPF_DYNPTR_TYPE_RINGBUF:
709 		return "ringbuf";
710 	case BPF_DYNPTR_TYPE_SKB:
711 		return "skb";
712 	case BPF_DYNPTR_TYPE_XDP:
713 		return "xdp";
714 	case BPF_DYNPTR_TYPE_INVALID:
715 		return "<invalid>";
716 	default:
717 		WARN_ONCE(1, "unknown dynptr type %d\n", type);
718 		return "<unknown>";
719 	}
720 }
721 
722 static const char *iter_type_str(const struct btf *btf, u32 btf_id)
723 {
724 	if (!btf || btf_id == 0)
725 		return "<invalid>";
726 
727 	/* we already validated that type is valid and has conforming name */
728 	return btf_type_name(btf, btf_id) + sizeof(ITER_PREFIX) - 1;
729 }
730 
731 static const char *iter_state_str(enum bpf_iter_state state)
732 {
733 	switch (state) {
734 	case BPF_ITER_STATE_ACTIVE:
735 		return "active";
736 	case BPF_ITER_STATE_DRAINED:
737 		return "drained";
738 	case BPF_ITER_STATE_INVALID:
739 		return "<invalid>";
740 	default:
741 		WARN_ONCE(1, "unknown iter state %d\n", state);
742 		return "<unknown>";
743 	}
744 }
745 
746 static void mark_reg_scratched(struct bpf_verifier_env *env, u32 regno)
747 {
748 	env->scratched_regs |= 1U << regno;
749 }
750 
751 static void mark_stack_slot_scratched(struct bpf_verifier_env *env, u32 spi)
752 {
753 	env->scratched_stack_slots |= 1ULL << spi;
754 }
755 
756 static bool reg_scratched(const struct bpf_verifier_env *env, u32 regno)
757 {
758 	return (env->scratched_regs >> regno) & 1;
759 }
760 
761 static bool stack_slot_scratched(const struct bpf_verifier_env *env, u64 regno)
762 {
763 	return (env->scratched_stack_slots >> regno) & 1;
764 }
765 
766 static bool verifier_state_scratched(const struct bpf_verifier_env *env)
767 {
768 	return env->scratched_regs || env->scratched_stack_slots;
769 }
770 
771 static void mark_verifier_state_clean(struct bpf_verifier_env *env)
772 {
773 	env->scratched_regs = 0U;
774 	env->scratched_stack_slots = 0ULL;
775 }
776 
777 /* Used for printing the entire verifier state. */
778 static void mark_verifier_state_scratched(struct bpf_verifier_env *env)
779 {
780 	env->scratched_regs = ~0U;
781 	env->scratched_stack_slots = ~0ULL;
782 }
783 
784 static enum bpf_dynptr_type arg_to_dynptr_type(enum bpf_arg_type arg_type)
785 {
786 	switch (arg_type & DYNPTR_TYPE_FLAG_MASK) {
787 	case DYNPTR_TYPE_LOCAL:
788 		return BPF_DYNPTR_TYPE_LOCAL;
789 	case DYNPTR_TYPE_RINGBUF:
790 		return BPF_DYNPTR_TYPE_RINGBUF;
791 	case DYNPTR_TYPE_SKB:
792 		return BPF_DYNPTR_TYPE_SKB;
793 	case DYNPTR_TYPE_XDP:
794 		return BPF_DYNPTR_TYPE_XDP;
795 	default:
796 		return BPF_DYNPTR_TYPE_INVALID;
797 	}
798 }
799 
800 static enum bpf_type_flag get_dynptr_type_flag(enum bpf_dynptr_type type)
801 {
802 	switch (type) {
803 	case BPF_DYNPTR_TYPE_LOCAL:
804 		return DYNPTR_TYPE_LOCAL;
805 	case BPF_DYNPTR_TYPE_RINGBUF:
806 		return DYNPTR_TYPE_RINGBUF;
807 	case BPF_DYNPTR_TYPE_SKB:
808 		return DYNPTR_TYPE_SKB;
809 	case BPF_DYNPTR_TYPE_XDP:
810 		return DYNPTR_TYPE_XDP;
811 	default:
812 		return 0;
813 	}
814 }
815 
816 static bool dynptr_type_refcounted(enum bpf_dynptr_type type)
817 {
818 	return type == BPF_DYNPTR_TYPE_RINGBUF;
819 }
820 
821 static void __mark_dynptr_reg(struct bpf_reg_state *reg,
822 			      enum bpf_dynptr_type type,
823 			      bool first_slot, int dynptr_id);
824 
825 static void __mark_reg_not_init(const struct bpf_verifier_env *env,
826 				struct bpf_reg_state *reg);
827 
828 static void mark_dynptr_stack_regs(struct bpf_verifier_env *env,
829 				   struct bpf_reg_state *sreg1,
830 				   struct bpf_reg_state *sreg2,
831 				   enum bpf_dynptr_type type)
832 {
833 	int id = ++env->id_gen;
834 
835 	__mark_dynptr_reg(sreg1, type, true, id);
836 	__mark_dynptr_reg(sreg2, type, false, id);
837 }
838 
839 static void mark_dynptr_cb_reg(struct bpf_verifier_env *env,
840 			       struct bpf_reg_state *reg,
841 			       enum bpf_dynptr_type type)
842 {
843 	__mark_dynptr_reg(reg, type, true, ++env->id_gen);
844 }
845 
846 static int destroy_if_dynptr_stack_slot(struct bpf_verifier_env *env,
847 				        struct bpf_func_state *state, int spi);
848 
849 static int mark_stack_slots_dynptr(struct bpf_verifier_env *env, struct bpf_reg_state *reg,
850 				   enum bpf_arg_type arg_type, int insn_idx)
851 {
852 	struct bpf_func_state *state = func(env, reg);
853 	enum bpf_dynptr_type type;
854 	int spi, i, id, err;
855 
856 	spi = dynptr_get_spi(env, reg);
857 	if (spi < 0)
858 		return spi;
859 
860 	/* We cannot assume both spi and spi - 1 belong to the same dynptr,
861 	 * hence we need to call destroy_if_dynptr_stack_slot twice for both,
862 	 * to ensure that for the following example:
863 	 *	[d1][d1][d2][d2]
864 	 * spi    3   2   1   0
865 	 * So marking spi = 2 should lead to destruction of both d1 and d2. In
866 	 * case they do belong to same dynptr, second call won't see slot_type
867 	 * as STACK_DYNPTR and will simply skip destruction.
868 	 */
869 	err = destroy_if_dynptr_stack_slot(env, state, spi);
870 	if (err)
871 		return err;
872 	err = destroy_if_dynptr_stack_slot(env, state, spi - 1);
873 	if (err)
874 		return err;
875 
876 	for (i = 0; i < BPF_REG_SIZE; i++) {
877 		state->stack[spi].slot_type[i] = STACK_DYNPTR;
878 		state->stack[spi - 1].slot_type[i] = STACK_DYNPTR;
879 	}
880 
881 	type = arg_to_dynptr_type(arg_type);
882 	if (type == BPF_DYNPTR_TYPE_INVALID)
883 		return -EINVAL;
884 
885 	mark_dynptr_stack_regs(env, &state->stack[spi].spilled_ptr,
886 			       &state->stack[spi - 1].spilled_ptr, type);
887 
888 	if (dynptr_type_refcounted(type)) {
889 		/* The id is used to track proper releasing */
890 		id = acquire_reference_state(env, insn_idx);
891 		if (id < 0)
892 			return id;
893 
894 		state->stack[spi].spilled_ptr.ref_obj_id = id;
895 		state->stack[spi - 1].spilled_ptr.ref_obj_id = id;
896 	}
897 
898 	state->stack[spi].spilled_ptr.live |= REG_LIVE_WRITTEN;
899 	state->stack[spi - 1].spilled_ptr.live |= REG_LIVE_WRITTEN;
900 
901 	return 0;
902 }
903 
904 static int unmark_stack_slots_dynptr(struct bpf_verifier_env *env, struct bpf_reg_state *reg)
905 {
906 	struct bpf_func_state *state = func(env, reg);
907 	int spi, i;
908 
909 	spi = dynptr_get_spi(env, reg);
910 	if (spi < 0)
911 		return spi;
912 
913 	for (i = 0; i < BPF_REG_SIZE; i++) {
914 		state->stack[spi].slot_type[i] = STACK_INVALID;
915 		state->stack[spi - 1].slot_type[i] = STACK_INVALID;
916 	}
917 
918 	/* Invalidate any slices associated with this dynptr */
919 	if (dynptr_type_refcounted(state->stack[spi].spilled_ptr.dynptr.type))
920 		WARN_ON_ONCE(release_reference(env, state->stack[spi].spilled_ptr.ref_obj_id));
921 
922 	__mark_reg_not_init(env, &state->stack[spi].spilled_ptr);
923 	__mark_reg_not_init(env, &state->stack[spi - 1].spilled_ptr);
924 
925 	/* Why do we need to set REG_LIVE_WRITTEN for STACK_INVALID slot?
926 	 *
927 	 * While we don't allow reading STACK_INVALID, it is still possible to
928 	 * do <8 byte writes marking some but not all slots as STACK_MISC. Then,
929 	 * helpers or insns can do partial read of that part without failing,
930 	 * but check_stack_range_initialized, check_stack_read_var_off, and
931 	 * check_stack_read_fixed_off will do mark_reg_read for all 8-bytes of
932 	 * the slot conservatively. Hence we need to prevent those liveness
933 	 * marking walks.
934 	 *
935 	 * This was not a problem before because STACK_INVALID is only set by
936 	 * default (where the default reg state has its reg->parent as NULL), or
937 	 * in clean_live_states after REG_LIVE_DONE (at which point
938 	 * mark_reg_read won't walk reg->parent chain), but not randomly during
939 	 * verifier state exploration (like we did above). Hence, for our case
940 	 * parentage chain will still be live (i.e. reg->parent may be
941 	 * non-NULL), while earlier reg->parent was NULL, so we need
942 	 * REG_LIVE_WRITTEN to screen off read marker propagation when it is
943 	 * done later on reads or by mark_dynptr_read as well to unnecessary
944 	 * mark registers in verifier state.
945 	 */
946 	state->stack[spi].spilled_ptr.live |= REG_LIVE_WRITTEN;
947 	state->stack[spi - 1].spilled_ptr.live |= REG_LIVE_WRITTEN;
948 
949 	return 0;
950 }
951 
952 static void __mark_reg_unknown(const struct bpf_verifier_env *env,
953 			       struct bpf_reg_state *reg);
954 
955 static void mark_reg_invalid(const struct bpf_verifier_env *env, struct bpf_reg_state *reg)
956 {
957 	if (!env->allow_ptr_leaks)
958 		__mark_reg_not_init(env, reg);
959 	else
960 		__mark_reg_unknown(env, reg);
961 }
962 
963 static int destroy_if_dynptr_stack_slot(struct bpf_verifier_env *env,
964 				        struct bpf_func_state *state, int spi)
965 {
966 	struct bpf_func_state *fstate;
967 	struct bpf_reg_state *dreg;
968 	int i, dynptr_id;
969 
970 	/* We always ensure that STACK_DYNPTR is never set partially,
971 	 * hence just checking for slot_type[0] is enough. This is
972 	 * different for STACK_SPILL, where it may be only set for
973 	 * 1 byte, so code has to use is_spilled_reg.
974 	 */
975 	if (state->stack[spi].slot_type[0] != STACK_DYNPTR)
976 		return 0;
977 
978 	/* Reposition spi to first slot */
979 	if (!state->stack[spi].spilled_ptr.dynptr.first_slot)
980 		spi = spi + 1;
981 
982 	if (dynptr_type_refcounted(state->stack[spi].spilled_ptr.dynptr.type)) {
983 		verbose(env, "cannot overwrite referenced dynptr\n");
984 		return -EINVAL;
985 	}
986 
987 	mark_stack_slot_scratched(env, spi);
988 	mark_stack_slot_scratched(env, spi - 1);
989 
990 	/* Writing partially to one dynptr stack slot destroys both. */
991 	for (i = 0; i < BPF_REG_SIZE; i++) {
992 		state->stack[spi].slot_type[i] = STACK_INVALID;
993 		state->stack[spi - 1].slot_type[i] = STACK_INVALID;
994 	}
995 
996 	dynptr_id = state->stack[spi].spilled_ptr.id;
997 	/* Invalidate any slices associated with this dynptr */
998 	bpf_for_each_reg_in_vstate(env->cur_state, fstate, dreg, ({
999 		/* Dynptr slices are only PTR_TO_MEM_OR_NULL and PTR_TO_MEM */
1000 		if (dreg->type != (PTR_TO_MEM | PTR_MAYBE_NULL) && dreg->type != PTR_TO_MEM)
1001 			continue;
1002 		if (dreg->dynptr_id == dynptr_id)
1003 			mark_reg_invalid(env, dreg);
1004 	}));
1005 
1006 	/* Do not release reference state, we are destroying dynptr on stack,
1007 	 * not using some helper to release it. Just reset register.
1008 	 */
1009 	__mark_reg_not_init(env, &state->stack[spi].spilled_ptr);
1010 	__mark_reg_not_init(env, &state->stack[spi - 1].spilled_ptr);
1011 
1012 	/* Same reason as unmark_stack_slots_dynptr above */
1013 	state->stack[spi].spilled_ptr.live |= REG_LIVE_WRITTEN;
1014 	state->stack[spi - 1].spilled_ptr.live |= REG_LIVE_WRITTEN;
1015 
1016 	return 0;
1017 }
1018 
1019 static bool is_dynptr_reg_valid_uninit(struct bpf_verifier_env *env, struct bpf_reg_state *reg)
1020 {
1021 	int spi;
1022 
1023 	if (reg->type == CONST_PTR_TO_DYNPTR)
1024 		return false;
1025 
1026 	spi = dynptr_get_spi(env, reg);
1027 
1028 	/* -ERANGE (i.e. spi not falling into allocated stack slots) isn't an
1029 	 * error because this just means the stack state hasn't been updated yet.
1030 	 * We will do check_mem_access to check and update stack bounds later.
1031 	 */
1032 	if (spi < 0 && spi != -ERANGE)
1033 		return false;
1034 
1035 	/* We don't need to check if the stack slots are marked by previous
1036 	 * dynptr initializations because we allow overwriting existing unreferenced
1037 	 * STACK_DYNPTR slots, see mark_stack_slots_dynptr which calls
1038 	 * destroy_if_dynptr_stack_slot to ensure dynptr objects at the slots we are
1039 	 * touching are completely destructed before we reinitialize them for a new
1040 	 * one. For referenced ones, destroy_if_dynptr_stack_slot returns an error early
1041 	 * instead of delaying it until the end where the user will get "Unreleased
1042 	 * reference" error.
1043 	 */
1044 	return true;
1045 }
1046 
1047 static bool is_dynptr_reg_valid_init(struct bpf_verifier_env *env, struct bpf_reg_state *reg)
1048 {
1049 	struct bpf_func_state *state = func(env, reg);
1050 	int i, spi;
1051 
1052 	/* This already represents first slot of initialized bpf_dynptr.
1053 	 *
1054 	 * CONST_PTR_TO_DYNPTR already has fixed and var_off as 0 due to
1055 	 * check_func_arg_reg_off's logic, so we don't need to check its
1056 	 * offset and alignment.
1057 	 */
1058 	if (reg->type == CONST_PTR_TO_DYNPTR)
1059 		return true;
1060 
1061 	spi = dynptr_get_spi(env, reg);
1062 	if (spi < 0)
1063 		return false;
1064 	if (!state->stack[spi].spilled_ptr.dynptr.first_slot)
1065 		return false;
1066 
1067 	for (i = 0; i < BPF_REG_SIZE; i++) {
1068 		if (state->stack[spi].slot_type[i] != STACK_DYNPTR ||
1069 		    state->stack[spi - 1].slot_type[i] != STACK_DYNPTR)
1070 			return false;
1071 	}
1072 
1073 	return true;
1074 }
1075 
1076 static bool is_dynptr_type_expected(struct bpf_verifier_env *env, struct bpf_reg_state *reg,
1077 				    enum bpf_arg_type arg_type)
1078 {
1079 	struct bpf_func_state *state = func(env, reg);
1080 	enum bpf_dynptr_type dynptr_type;
1081 	int spi;
1082 
1083 	/* ARG_PTR_TO_DYNPTR takes any type of dynptr */
1084 	if (arg_type == ARG_PTR_TO_DYNPTR)
1085 		return true;
1086 
1087 	dynptr_type = arg_to_dynptr_type(arg_type);
1088 	if (reg->type == CONST_PTR_TO_DYNPTR) {
1089 		return reg->dynptr.type == dynptr_type;
1090 	} else {
1091 		spi = dynptr_get_spi(env, reg);
1092 		if (spi < 0)
1093 			return false;
1094 		return state->stack[spi].spilled_ptr.dynptr.type == dynptr_type;
1095 	}
1096 }
1097 
1098 static void __mark_reg_known_zero(struct bpf_reg_state *reg);
1099 
1100 static int mark_stack_slots_iter(struct bpf_verifier_env *env,
1101 				 struct bpf_reg_state *reg, int insn_idx,
1102 				 struct btf *btf, u32 btf_id, int nr_slots)
1103 {
1104 	struct bpf_func_state *state = func(env, reg);
1105 	int spi, i, j, id;
1106 
1107 	spi = iter_get_spi(env, reg, nr_slots);
1108 	if (spi < 0)
1109 		return spi;
1110 
1111 	id = acquire_reference_state(env, insn_idx);
1112 	if (id < 0)
1113 		return id;
1114 
1115 	for (i = 0; i < nr_slots; i++) {
1116 		struct bpf_stack_state *slot = &state->stack[spi - i];
1117 		struct bpf_reg_state *st = &slot->spilled_ptr;
1118 
1119 		__mark_reg_known_zero(st);
1120 		st->type = PTR_TO_STACK; /* we don't have dedicated reg type */
1121 		st->live |= REG_LIVE_WRITTEN;
1122 		st->ref_obj_id = i == 0 ? id : 0;
1123 		st->iter.btf = btf;
1124 		st->iter.btf_id = btf_id;
1125 		st->iter.state = BPF_ITER_STATE_ACTIVE;
1126 		st->iter.depth = 0;
1127 
1128 		for (j = 0; j < BPF_REG_SIZE; j++)
1129 			slot->slot_type[j] = STACK_ITER;
1130 
1131 		mark_stack_slot_scratched(env, spi - i);
1132 	}
1133 
1134 	return 0;
1135 }
1136 
1137 static int unmark_stack_slots_iter(struct bpf_verifier_env *env,
1138 				   struct bpf_reg_state *reg, int nr_slots)
1139 {
1140 	struct bpf_func_state *state = func(env, reg);
1141 	int spi, i, j;
1142 
1143 	spi = iter_get_spi(env, reg, nr_slots);
1144 	if (spi < 0)
1145 		return spi;
1146 
1147 	for (i = 0; i < nr_slots; i++) {
1148 		struct bpf_stack_state *slot = &state->stack[spi - i];
1149 		struct bpf_reg_state *st = &slot->spilled_ptr;
1150 
1151 		if (i == 0)
1152 			WARN_ON_ONCE(release_reference(env, st->ref_obj_id));
1153 
1154 		__mark_reg_not_init(env, st);
1155 
1156 		/* see unmark_stack_slots_dynptr() for why we need to set REG_LIVE_WRITTEN */
1157 		st->live |= REG_LIVE_WRITTEN;
1158 
1159 		for (j = 0; j < BPF_REG_SIZE; j++)
1160 			slot->slot_type[j] = STACK_INVALID;
1161 
1162 		mark_stack_slot_scratched(env, spi - i);
1163 	}
1164 
1165 	return 0;
1166 }
1167 
1168 static bool is_iter_reg_valid_uninit(struct bpf_verifier_env *env,
1169 				     struct bpf_reg_state *reg, int nr_slots)
1170 {
1171 	struct bpf_func_state *state = func(env, reg);
1172 	int spi, i, j;
1173 
1174 	/* For -ERANGE (i.e. spi not falling into allocated stack slots), we
1175 	 * will do check_mem_access to check and update stack bounds later, so
1176 	 * return true for that case.
1177 	 */
1178 	spi = iter_get_spi(env, reg, nr_slots);
1179 	if (spi == -ERANGE)
1180 		return true;
1181 	if (spi < 0)
1182 		return false;
1183 
1184 	for (i = 0; i < nr_slots; i++) {
1185 		struct bpf_stack_state *slot = &state->stack[spi - i];
1186 
1187 		for (j = 0; j < BPF_REG_SIZE; j++)
1188 			if (slot->slot_type[j] == STACK_ITER)
1189 				return false;
1190 	}
1191 
1192 	return true;
1193 }
1194 
1195 static bool is_iter_reg_valid_init(struct bpf_verifier_env *env, struct bpf_reg_state *reg,
1196 				   struct btf *btf, u32 btf_id, int nr_slots)
1197 {
1198 	struct bpf_func_state *state = func(env, reg);
1199 	int spi, i, j;
1200 
1201 	spi = iter_get_spi(env, reg, nr_slots);
1202 	if (spi < 0)
1203 		return false;
1204 
1205 	for (i = 0; i < nr_slots; i++) {
1206 		struct bpf_stack_state *slot = &state->stack[spi - i];
1207 		struct bpf_reg_state *st = &slot->spilled_ptr;
1208 
1209 		/* only main (first) slot has ref_obj_id set */
1210 		if (i == 0 && !st->ref_obj_id)
1211 			return false;
1212 		if (i != 0 && st->ref_obj_id)
1213 			return false;
1214 		if (st->iter.btf != btf || st->iter.btf_id != btf_id)
1215 			return false;
1216 
1217 		for (j = 0; j < BPF_REG_SIZE; j++)
1218 			if (slot->slot_type[j] != STACK_ITER)
1219 				return false;
1220 	}
1221 
1222 	return true;
1223 }
1224 
1225 /* Check if given stack slot is "special":
1226  *   - spilled register state (STACK_SPILL);
1227  *   - dynptr state (STACK_DYNPTR);
1228  *   - iter state (STACK_ITER).
1229  */
1230 static bool is_stack_slot_special(const struct bpf_stack_state *stack)
1231 {
1232 	enum bpf_stack_slot_type type = stack->slot_type[BPF_REG_SIZE - 1];
1233 
1234 	switch (type) {
1235 	case STACK_SPILL:
1236 	case STACK_DYNPTR:
1237 	case STACK_ITER:
1238 		return true;
1239 	case STACK_INVALID:
1240 	case STACK_MISC:
1241 	case STACK_ZERO:
1242 		return false;
1243 	default:
1244 		WARN_ONCE(1, "unknown stack slot type %d\n", type);
1245 		return true;
1246 	}
1247 }
1248 
1249 /* The reg state of a pointer or a bounded scalar was saved when
1250  * it was spilled to the stack.
1251  */
1252 static bool is_spilled_reg(const struct bpf_stack_state *stack)
1253 {
1254 	return stack->slot_type[BPF_REG_SIZE - 1] == STACK_SPILL;
1255 }
1256 
1257 static void scrub_spilled_slot(u8 *stype)
1258 {
1259 	if (*stype != STACK_INVALID)
1260 		*stype = STACK_MISC;
1261 }
1262 
1263 static void print_verifier_state(struct bpf_verifier_env *env,
1264 				 const struct bpf_func_state *state,
1265 				 bool print_all)
1266 {
1267 	const struct bpf_reg_state *reg;
1268 	enum bpf_reg_type t;
1269 	int i;
1270 
1271 	if (state->frameno)
1272 		verbose(env, " frame%d:", state->frameno);
1273 	for (i = 0; i < MAX_BPF_REG; i++) {
1274 		reg = &state->regs[i];
1275 		t = reg->type;
1276 		if (t == NOT_INIT)
1277 			continue;
1278 		if (!print_all && !reg_scratched(env, i))
1279 			continue;
1280 		verbose(env, " R%d", i);
1281 		print_liveness(env, reg->live);
1282 		verbose(env, "=");
1283 		if (t == SCALAR_VALUE && reg->precise)
1284 			verbose(env, "P");
1285 		if ((t == SCALAR_VALUE || t == PTR_TO_STACK) &&
1286 		    tnum_is_const(reg->var_off)) {
1287 			/* reg->off should be 0 for SCALAR_VALUE */
1288 			verbose(env, "%s", t == SCALAR_VALUE ? "" : reg_type_str(env, t));
1289 			verbose(env, "%lld", reg->var_off.value + reg->off);
1290 		} else {
1291 			const char *sep = "";
1292 
1293 			verbose(env, "%s", reg_type_str(env, t));
1294 			if (base_type(t) == PTR_TO_BTF_ID)
1295 				verbose(env, "%s", btf_type_name(reg->btf, reg->btf_id));
1296 			verbose(env, "(");
1297 /*
1298  * _a stands for append, was shortened to avoid multiline statements below.
1299  * This macro is used to output a comma separated list of attributes.
1300  */
1301 #define verbose_a(fmt, ...) ({ verbose(env, "%s" fmt, sep, __VA_ARGS__); sep = ","; })
1302 
1303 			if (reg->id)
1304 				verbose_a("id=%d", reg->id);
1305 			if (reg->ref_obj_id)
1306 				verbose_a("ref_obj_id=%d", reg->ref_obj_id);
1307 			if (type_is_non_owning_ref(reg->type))
1308 				verbose_a("%s", "non_own_ref");
1309 			if (t != SCALAR_VALUE)
1310 				verbose_a("off=%d", reg->off);
1311 			if (type_is_pkt_pointer(t))
1312 				verbose_a("r=%d", reg->range);
1313 			else if (base_type(t) == CONST_PTR_TO_MAP ||
1314 				 base_type(t) == PTR_TO_MAP_KEY ||
1315 				 base_type(t) == PTR_TO_MAP_VALUE)
1316 				verbose_a("ks=%d,vs=%d",
1317 					  reg->map_ptr->key_size,
1318 					  reg->map_ptr->value_size);
1319 			if (tnum_is_const(reg->var_off)) {
1320 				/* Typically an immediate SCALAR_VALUE, but
1321 				 * could be a pointer whose offset is too big
1322 				 * for reg->off
1323 				 */
1324 				verbose_a("imm=%llx", reg->var_off.value);
1325 			} else {
1326 				if (reg->smin_value != reg->umin_value &&
1327 				    reg->smin_value != S64_MIN)
1328 					verbose_a("smin=%lld", (long long)reg->smin_value);
1329 				if (reg->smax_value != reg->umax_value &&
1330 				    reg->smax_value != S64_MAX)
1331 					verbose_a("smax=%lld", (long long)reg->smax_value);
1332 				if (reg->umin_value != 0)
1333 					verbose_a("umin=%llu", (unsigned long long)reg->umin_value);
1334 				if (reg->umax_value != U64_MAX)
1335 					verbose_a("umax=%llu", (unsigned long long)reg->umax_value);
1336 				if (!tnum_is_unknown(reg->var_off)) {
1337 					char tn_buf[48];
1338 
1339 					tnum_strn(tn_buf, sizeof(tn_buf), reg->var_off);
1340 					verbose_a("var_off=%s", tn_buf);
1341 				}
1342 				if (reg->s32_min_value != reg->smin_value &&
1343 				    reg->s32_min_value != S32_MIN)
1344 					verbose_a("s32_min=%d", (int)(reg->s32_min_value));
1345 				if (reg->s32_max_value != reg->smax_value &&
1346 				    reg->s32_max_value != S32_MAX)
1347 					verbose_a("s32_max=%d", (int)(reg->s32_max_value));
1348 				if (reg->u32_min_value != reg->umin_value &&
1349 				    reg->u32_min_value != U32_MIN)
1350 					verbose_a("u32_min=%d", (int)(reg->u32_min_value));
1351 				if (reg->u32_max_value != reg->umax_value &&
1352 				    reg->u32_max_value != U32_MAX)
1353 					verbose_a("u32_max=%d", (int)(reg->u32_max_value));
1354 			}
1355 #undef verbose_a
1356 
1357 			verbose(env, ")");
1358 		}
1359 	}
1360 	for (i = 0; i < state->allocated_stack / BPF_REG_SIZE; i++) {
1361 		char types_buf[BPF_REG_SIZE + 1];
1362 		bool valid = false;
1363 		int j;
1364 
1365 		for (j = 0; j < BPF_REG_SIZE; j++) {
1366 			if (state->stack[i].slot_type[j] != STACK_INVALID)
1367 				valid = true;
1368 			types_buf[j] = slot_type_char[state->stack[i].slot_type[j]];
1369 		}
1370 		types_buf[BPF_REG_SIZE] = 0;
1371 		if (!valid)
1372 			continue;
1373 		if (!print_all && !stack_slot_scratched(env, i))
1374 			continue;
1375 		switch (state->stack[i].slot_type[BPF_REG_SIZE - 1]) {
1376 		case STACK_SPILL:
1377 			reg = &state->stack[i].spilled_ptr;
1378 			t = reg->type;
1379 
1380 			verbose(env, " fp%d", (-i - 1) * BPF_REG_SIZE);
1381 			print_liveness(env, reg->live);
1382 			verbose(env, "=%s", t == SCALAR_VALUE ? "" : reg_type_str(env, t));
1383 			if (t == SCALAR_VALUE && reg->precise)
1384 				verbose(env, "P");
1385 			if (t == SCALAR_VALUE && tnum_is_const(reg->var_off))
1386 				verbose(env, "%lld", reg->var_off.value + reg->off);
1387 			break;
1388 		case STACK_DYNPTR:
1389 			i += BPF_DYNPTR_NR_SLOTS - 1;
1390 			reg = &state->stack[i].spilled_ptr;
1391 
1392 			verbose(env, " fp%d", (-i - 1) * BPF_REG_SIZE);
1393 			print_liveness(env, reg->live);
1394 			verbose(env, "=dynptr_%s", dynptr_type_str(reg->dynptr.type));
1395 			if (reg->ref_obj_id)
1396 				verbose(env, "(ref_id=%d)", reg->ref_obj_id);
1397 			break;
1398 		case STACK_ITER:
1399 			/* only main slot has ref_obj_id set; skip others */
1400 			reg = &state->stack[i].spilled_ptr;
1401 			if (!reg->ref_obj_id)
1402 				continue;
1403 
1404 			verbose(env, " fp%d", (-i - 1) * BPF_REG_SIZE);
1405 			print_liveness(env, reg->live);
1406 			verbose(env, "=iter_%s(ref_id=%d,state=%s,depth=%u)",
1407 				iter_type_str(reg->iter.btf, reg->iter.btf_id),
1408 				reg->ref_obj_id, iter_state_str(reg->iter.state),
1409 				reg->iter.depth);
1410 			break;
1411 		case STACK_MISC:
1412 		case STACK_ZERO:
1413 		default:
1414 			reg = &state->stack[i].spilled_ptr;
1415 
1416 			for (j = 0; j < BPF_REG_SIZE; j++)
1417 				types_buf[j] = slot_type_char[state->stack[i].slot_type[j]];
1418 			types_buf[BPF_REG_SIZE] = 0;
1419 
1420 			verbose(env, " fp%d", (-i - 1) * BPF_REG_SIZE);
1421 			print_liveness(env, reg->live);
1422 			verbose(env, "=%s", types_buf);
1423 			break;
1424 		}
1425 	}
1426 	if (state->acquired_refs && state->refs[0].id) {
1427 		verbose(env, " refs=%d", state->refs[0].id);
1428 		for (i = 1; i < state->acquired_refs; i++)
1429 			if (state->refs[i].id)
1430 				verbose(env, ",%d", state->refs[i].id);
1431 	}
1432 	if (state->in_callback_fn)
1433 		verbose(env, " cb");
1434 	if (state->in_async_callback_fn)
1435 		verbose(env, " async_cb");
1436 	verbose(env, "\n");
1437 	mark_verifier_state_clean(env);
1438 }
1439 
1440 static inline u32 vlog_alignment(u32 pos)
1441 {
1442 	return round_up(max(pos + BPF_LOG_MIN_ALIGNMENT / 2, BPF_LOG_ALIGNMENT),
1443 			BPF_LOG_MIN_ALIGNMENT) - pos - 1;
1444 }
1445 
1446 static void print_insn_state(struct bpf_verifier_env *env,
1447 			     const struct bpf_func_state *state)
1448 {
1449 	if (env->prev_log_pos && env->prev_log_pos == env->log.end_pos) {
1450 		/* remove new line character */
1451 		bpf_vlog_reset(&env->log, env->prev_log_pos - 1);
1452 		verbose(env, "%*c;", vlog_alignment(env->prev_insn_print_pos), ' ');
1453 	} else {
1454 		verbose(env, "%d:", env->insn_idx);
1455 	}
1456 	print_verifier_state(env, state, false);
1457 }
1458 
1459 /* copy array src of length n * size bytes to dst. dst is reallocated if it's too
1460  * small to hold src. This is different from krealloc since we don't want to preserve
1461  * the contents of dst.
1462  *
1463  * Leaves dst untouched if src is NULL or length is zero. Returns NULL if memory could
1464  * not be allocated.
1465  */
1466 static void *copy_array(void *dst, const void *src, size_t n, size_t size, gfp_t flags)
1467 {
1468 	size_t alloc_bytes;
1469 	void *orig = dst;
1470 	size_t bytes;
1471 
1472 	if (ZERO_OR_NULL_PTR(src))
1473 		goto out;
1474 
1475 	if (unlikely(check_mul_overflow(n, size, &bytes)))
1476 		return NULL;
1477 
1478 	alloc_bytes = max(ksize(orig), kmalloc_size_roundup(bytes));
1479 	dst = krealloc(orig, alloc_bytes, flags);
1480 	if (!dst) {
1481 		kfree(orig);
1482 		return NULL;
1483 	}
1484 
1485 	memcpy(dst, src, bytes);
1486 out:
1487 	return dst ? dst : ZERO_SIZE_PTR;
1488 }
1489 
1490 /* resize an array from old_n items to new_n items. the array is reallocated if it's too
1491  * small to hold new_n items. new items are zeroed out if the array grows.
1492  *
1493  * Contrary to krealloc_array, does not free arr if new_n is zero.
1494  */
1495 static void *realloc_array(void *arr, size_t old_n, size_t new_n, size_t size)
1496 {
1497 	size_t alloc_size;
1498 	void *new_arr;
1499 
1500 	if (!new_n || old_n == new_n)
1501 		goto out;
1502 
1503 	alloc_size = kmalloc_size_roundup(size_mul(new_n, size));
1504 	new_arr = krealloc(arr, alloc_size, GFP_KERNEL);
1505 	if (!new_arr) {
1506 		kfree(arr);
1507 		return NULL;
1508 	}
1509 	arr = new_arr;
1510 
1511 	if (new_n > old_n)
1512 		memset(arr + old_n * size, 0, (new_n - old_n) * size);
1513 
1514 out:
1515 	return arr ? arr : ZERO_SIZE_PTR;
1516 }
1517 
1518 static int copy_reference_state(struct bpf_func_state *dst, const struct bpf_func_state *src)
1519 {
1520 	dst->refs = copy_array(dst->refs, src->refs, src->acquired_refs,
1521 			       sizeof(struct bpf_reference_state), GFP_KERNEL);
1522 	if (!dst->refs)
1523 		return -ENOMEM;
1524 
1525 	dst->acquired_refs = src->acquired_refs;
1526 	return 0;
1527 }
1528 
1529 static int copy_stack_state(struct bpf_func_state *dst, const struct bpf_func_state *src)
1530 {
1531 	size_t n = src->allocated_stack / BPF_REG_SIZE;
1532 
1533 	dst->stack = copy_array(dst->stack, src->stack, n, sizeof(struct bpf_stack_state),
1534 				GFP_KERNEL);
1535 	if (!dst->stack)
1536 		return -ENOMEM;
1537 
1538 	dst->allocated_stack = src->allocated_stack;
1539 	return 0;
1540 }
1541 
1542 static int resize_reference_state(struct bpf_func_state *state, size_t n)
1543 {
1544 	state->refs = realloc_array(state->refs, state->acquired_refs, n,
1545 				    sizeof(struct bpf_reference_state));
1546 	if (!state->refs)
1547 		return -ENOMEM;
1548 
1549 	state->acquired_refs = n;
1550 	return 0;
1551 }
1552 
1553 static int grow_stack_state(struct bpf_func_state *state, int size)
1554 {
1555 	size_t old_n = state->allocated_stack / BPF_REG_SIZE, n = size / BPF_REG_SIZE;
1556 
1557 	if (old_n >= n)
1558 		return 0;
1559 
1560 	state->stack = realloc_array(state->stack, old_n, n, sizeof(struct bpf_stack_state));
1561 	if (!state->stack)
1562 		return -ENOMEM;
1563 
1564 	state->allocated_stack = size;
1565 	return 0;
1566 }
1567 
1568 /* Acquire a pointer id from the env and update the state->refs to include
1569  * this new pointer reference.
1570  * On success, returns a valid pointer id to associate with the register
1571  * On failure, returns a negative errno.
1572  */
1573 static int acquire_reference_state(struct bpf_verifier_env *env, int insn_idx)
1574 {
1575 	struct bpf_func_state *state = cur_func(env);
1576 	int new_ofs = state->acquired_refs;
1577 	int id, err;
1578 
1579 	err = resize_reference_state(state, state->acquired_refs + 1);
1580 	if (err)
1581 		return err;
1582 	id = ++env->id_gen;
1583 	state->refs[new_ofs].id = id;
1584 	state->refs[new_ofs].insn_idx = insn_idx;
1585 	state->refs[new_ofs].callback_ref = state->in_callback_fn ? state->frameno : 0;
1586 
1587 	return id;
1588 }
1589 
1590 /* release function corresponding to acquire_reference_state(). Idempotent. */
1591 static int release_reference_state(struct bpf_func_state *state, int ptr_id)
1592 {
1593 	int i, last_idx;
1594 
1595 	last_idx = state->acquired_refs - 1;
1596 	for (i = 0; i < state->acquired_refs; i++) {
1597 		if (state->refs[i].id == ptr_id) {
1598 			/* Cannot release caller references in callbacks */
1599 			if (state->in_callback_fn && state->refs[i].callback_ref != state->frameno)
1600 				return -EINVAL;
1601 			if (last_idx && i != last_idx)
1602 				memcpy(&state->refs[i], &state->refs[last_idx],
1603 				       sizeof(*state->refs));
1604 			memset(&state->refs[last_idx], 0, sizeof(*state->refs));
1605 			state->acquired_refs--;
1606 			return 0;
1607 		}
1608 	}
1609 	return -EINVAL;
1610 }
1611 
1612 static void free_func_state(struct bpf_func_state *state)
1613 {
1614 	if (!state)
1615 		return;
1616 	kfree(state->refs);
1617 	kfree(state->stack);
1618 	kfree(state);
1619 }
1620 
1621 static void clear_jmp_history(struct bpf_verifier_state *state)
1622 {
1623 	kfree(state->jmp_history);
1624 	state->jmp_history = NULL;
1625 	state->jmp_history_cnt = 0;
1626 }
1627 
1628 static void free_verifier_state(struct bpf_verifier_state *state,
1629 				bool free_self)
1630 {
1631 	int i;
1632 
1633 	for (i = 0; i <= state->curframe; i++) {
1634 		free_func_state(state->frame[i]);
1635 		state->frame[i] = NULL;
1636 	}
1637 	clear_jmp_history(state);
1638 	if (free_self)
1639 		kfree(state);
1640 }
1641 
1642 /* copy verifier state from src to dst growing dst stack space
1643  * when necessary to accommodate larger src stack
1644  */
1645 static int copy_func_state(struct bpf_func_state *dst,
1646 			   const struct bpf_func_state *src)
1647 {
1648 	int err;
1649 
1650 	memcpy(dst, src, offsetof(struct bpf_func_state, acquired_refs));
1651 	err = copy_reference_state(dst, src);
1652 	if (err)
1653 		return err;
1654 	return copy_stack_state(dst, src);
1655 }
1656 
1657 static int copy_verifier_state(struct bpf_verifier_state *dst_state,
1658 			       const struct bpf_verifier_state *src)
1659 {
1660 	struct bpf_func_state *dst;
1661 	int i, err;
1662 
1663 	dst_state->jmp_history = copy_array(dst_state->jmp_history, src->jmp_history,
1664 					    src->jmp_history_cnt, sizeof(struct bpf_idx_pair),
1665 					    GFP_USER);
1666 	if (!dst_state->jmp_history)
1667 		return -ENOMEM;
1668 	dst_state->jmp_history_cnt = src->jmp_history_cnt;
1669 
1670 	/* if dst has more stack frames then src frame, free them */
1671 	for (i = src->curframe + 1; i <= dst_state->curframe; i++) {
1672 		free_func_state(dst_state->frame[i]);
1673 		dst_state->frame[i] = NULL;
1674 	}
1675 	dst_state->speculative = src->speculative;
1676 	dst_state->active_rcu_lock = src->active_rcu_lock;
1677 	dst_state->curframe = src->curframe;
1678 	dst_state->active_lock.ptr = src->active_lock.ptr;
1679 	dst_state->active_lock.id = src->active_lock.id;
1680 	dst_state->branches = src->branches;
1681 	dst_state->parent = src->parent;
1682 	dst_state->first_insn_idx = src->first_insn_idx;
1683 	dst_state->last_insn_idx = src->last_insn_idx;
1684 	for (i = 0; i <= src->curframe; i++) {
1685 		dst = dst_state->frame[i];
1686 		if (!dst) {
1687 			dst = kzalloc(sizeof(*dst), GFP_KERNEL);
1688 			if (!dst)
1689 				return -ENOMEM;
1690 			dst_state->frame[i] = dst;
1691 		}
1692 		err = copy_func_state(dst, src->frame[i]);
1693 		if (err)
1694 			return err;
1695 	}
1696 	return 0;
1697 }
1698 
1699 static void update_branch_counts(struct bpf_verifier_env *env, struct bpf_verifier_state *st)
1700 {
1701 	while (st) {
1702 		u32 br = --st->branches;
1703 
1704 		/* WARN_ON(br > 1) technically makes sense here,
1705 		 * but see comment in push_stack(), hence:
1706 		 */
1707 		WARN_ONCE((int)br < 0,
1708 			  "BUG update_branch_counts:branches_to_explore=%d\n",
1709 			  br);
1710 		if (br)
1711 			break;
1712 		st = st->parent;
1713 	}
1714 }
1715 
1716 static int pop_stack(struct bpf_verifier_env *env, int *prev_insn_idx,
1717 		     int *insn_idx, bool pop_log)
1718 {
1719 	struct bpf_verifier_state *cur = env->cur_state;
1720 	struct bpf_verifier_stack_elem *elem, *head = env->head;
1721 	int err;
1722 
1723 	if (env->head == NULL)
1724 		return -ENOENT;
1725 
1726 	if (cur) {
1727 		err = copy_verifier_state(cur, &head->st);
1728 		if (err)
1729 			return err;
1730 	}
1731 	if (pop_log)
1732 		bpf_vlog_reset(&env->log, head->log_pos);
1733 	if (insn_idx)
1734 		*insn_idx = head->insn_idx;
1735 	if (prev_insn_idx)
1736 		*prev_insn_idx = head->prev_insn_idx;
1737 	elem = head->next;
1738 	free_verifier_state(&head->st, false);
1739 	kfree(head);
1740 	env->head = elem;
1741 	env->stack_size--;
1742 	return 0;
1743 }
1744 
1745 static struct bpf_verifier_state *push_stack(struct bpf_verifier_env *env,
1746 					     int insn_idx, int prev_insn_idx,
1747 					     bool speculative)
1748 {
1749 	struct bpf_verifier_state *cur = env->cur_state;
1750 	struct bpf_verifier_stack_elem *elem;
1751 	int err;
1752 
1753 	elem = kzalloc(sizeof(struct bpf_verifier_stack_elem), GFP_KERNEL);
1754 	if (!elem)
1755 		goto err;
1756 
1757 	elem->insn_idx = insn_idx;
1758 	elem->prev_insn_idx = prev_insn_idx;
1759 	elem->next = env->head;
1760 	elem->log_pos = env->log.end_pos;
1761 	env->head = elem;
1762 	env->stack_size++;
1763 	err = copy_verifier_state(&elem->st, cur);
1764 	if (err)
1765 		goto err;
1766 	elem->st.speculative |= speculative;
1767 	if (env->stack_size > BPF_COMPLEXITY_LIMIT_JMP_SEQ) {
1768 		verbose(env, "The sequence of %d jumps is too complex.\n",
1769 			env->stack_size);
1770 		goto err;
1771 	}
1772 	if (elem->st.parent) {
1773 		++elem->st.parent->branches;
1774 		/* WARN_ON(branches > 2) technically makes sense here,
1775 		 * but
1776 		 * 1. speculative states will bump 'branches' for non-branch
1777 		 * instructions
1778 		 * 2. is_state_visited() heuristics may decide not to create
1779 		 * a new state for a sequence of branches and all such current
1780 		 * and cloned states will be pointing to a single parent state
1781 		 * which might have large 'branches' count.
1782 		 */
1783 	}
1784 	return &elem->st;
1785 err:
1786 	free_verifier_state(env->cur_state, true);
1787 	env->cur_state = NULL;
1788 	/* pop all elements and return */
1789 	while (!pop_stack(env, NULL, NULL, false));
1790 	return NULL;
1791 }
1792 
1793 #define CALLER_SAVED_REGS 6
1794 static const int caller_saved[CALLER_SAVED_REGS] = {
1795 	BPF_REG_0, BPF_REG_1, BPF_REG_2, BPF_REG_3, BPF_REG_4, BPF_REG_5
1796 };
1797 
1798 /* This helper doesn't clear reg->id */
1799 static void ___mark_reg_known(struct bpf_reg_state *reg, u64 imm)
1800 {
1801 	reg->var_off = tnum_const(imm);
1802 	reg->smin_value = (s64)imm;
1803 	reg->smax_value = (s64)imm;
1804 	reg->umin_value = imm;
1805 	reg->umax_value = imm;
1806 
1807 	reg->s32_min_value = (s32)imm;
1808 	reg->s32_max_value = (s32)imm;
1809 	reg->u32_min_value = (u32)imm;
1810 	reg->u32_max_value = (u32)imm;
1811 }
1812 
1813 /* Mark the unknown part of a register (variable offset or scalar value) as
1814  * known to have the value @imm.
1815  */
1816 static void __mark_reg_known(struct bpf_reg_state *reg, u64 imm)
1817 {
1818 	/* Clear off and union(map_ptr, range) */
1819 	memset(((u8 *)reg) + sizeof(reg->type), 0,
1820 	       offsetof(struct bpf_reg_state, var_off) - sizeof(reg->type));
1821 	reg->id = 0;
1822 	reg->ref_obj_id = 0;
1823 	___mark_reg_known(reg, imm);
1824 }
1825 
1826 static void __mark_reg32_known(struct bpf_reg_state *reg, u64 imm)
1827 {
1828 	reg->var_off = tnum_const_subreg(reg->var_off, imm);
1829 	reg->s32_min_value = (s32)imm;
1830 	reg->s32_max_value = (s32)imm;
1831 	reg->u32_min_value = (u32)imm;
1832 	reg->u32_max_value = (u32)imm;
1833 }
1834 
1835 /* Mark the 'variable offset' part of a register as zero.  This should be
1836  * used only on registers holding a pointer type.
1837  */
1838 static void __mark_reg_known_zero(struct bpf_reg_state *reg)
1839 {
1840 	__mark_reg_known(reg, 0);
1841 }
1842 
1843 static void __mark_reg_const_zero(struct bpf_reg_state *reg)
1844 {
1845 	__mark_reg_known(reg, 0);
1846 	reg->type = SCALAR_VALUE;
1847 }
1848 
1849 static void mark_reg_known_zero(struct bpf_verifier_env *env,
1850 				struct bpf_reg_state *regs, u32 regno)
1851 {
1852 	if (WARN_ON(regno >= MAX_BPF_REG)) {
1853 		verbose(env, "mark_reg_known_zero(regs, %u)\n", regno);
1854 		/* Something bad happened, let's kill all regs */
1855 		for (regno = 0; regno < MAX_BPF_REG; regno++)
1856 			__mark_reg_not_init(env, regs + regno);
1857 		return;
1858 	}
1859 	__mark_reg_known_zero(regs + regno);
1860 }
1861 
1862 static void __mark_dynptr_reg(struct bpf_reg_state *reg, enum bpf_dynptr_type type,
1863 			      bool first_slot, int dynptr_id)
1864 {
1865 	/* reg->type has no meaning for STACK_DYNPTR, but when we set reg for
1866 	 * callback arguments, it does need to be CONST_PTR_TO_DYNPTR, so simply
1867 	 * set it unconditionally as it is ignored for STACK_DYNPTR anyway.
1868 	 */
1869 	__mark_reg_known_zero(reg);
1870 	reg->type = CONST_PTR_TO_DYNPTR;
1871 	/* Give each dynptr a unique id to uniquely associate slices to it. */
1872 	reg->id = dynptr_id;
1873 	reg->dynptr.type = type;
1874 	reg->dynptr.first_slot = first_slot;
1875 }
1876 
1877 static void mark_ptr_not_null_reg(struct bpf_reg_state *reg)
1878 {
1879 	if (base_type(reg->type) == PTR_TO_MAP_VALUE) {
1880 		const struct bpf_map *map = reg->map_ptr;
1881 
1882 		if (map->inner_map_meta) {
1883 			reg->type = CONST_PTR_TO_MAP;
1884 			reg->map_ptr = map->inner_map_meta;
1885 			/* transfer reg's id which is unique for every map_lookup_elem
1886 			 * as UID of the inner map.
1887 			 */
1888 			if (btf_record_has_field(map->inner_map_meta->record, BPF_TIMER))
1889 				reg->map_uid = reg->id;
1890 		} else if (map->map_type == BPF_MAP_TYPE_XSKMAP) {
1891 			reg->type = PTR_TO_XDP_SOCK;
1892 		} else if (map->map_type == BPF_MAP_TYPE_SOCKMAP ||
1893 			   map->map_type == BPF_MAP_TYPE_SOCKHASH) {
1894 			reg->type = PTR_TO_SOCKET;
1895 		} else {
1896 			reg->type = PTR_TO_MAP_VALUE;
1897 		}
1898 		return;
1899 	}
1900 
1901 	reg->type &= ~PTR_MAYBE_NULL;
1902 }
1903 
1904 static void mark_reg_graph_node(struct bpf_reg_state *regs, u32 regno,
1905 				struct btf_field_graph_root *ds_head)
1906 {
1907 	__mark_reg_known_zero(&regs[regno]);
1908 	regs[regno].type = PTR_TO_BTF_ID | MEM_ALLOC;
1909 	regs[regno].btf = ds_head->btf;
1910 	regs[regno].btf_id = ds_head->value_btf_id;
1911 	regs[regno].off = ds_head->node_offset;
1912 }
1913 
1914 static bool reg_is_pkt_pointer(const struct bpf_reg_state *reg)
1915 {
1916 	return type_is_pkt_pointer(reg->type);
1917 }
1918 
1919 static bool reg_is_pkt_pointer_any(const struct bpf_reg_state *reg)
1920 {
1921 	return reg_is_pkt_pointer(reg) ||
1922 	       reg->type == PTR_TO_PACKET_END;
1923 }
1924 
1925 static bool reg_is_dynptr_slice_pkt(const struct bpf_reg_state *reg)
1926 {
1927 	return base_type(reg->type) == PTR_TO_MEM &&
1928 		(reg->type & DYNPTR_TYPE_SKB || reg->type & DYNPTR_TYPE_XDP);
1929 }
1930 
1931 /* Unmodified PTR_TO_PACKET[_META,_END] register from ctx access. */
1932 static bool reg_is_init_pkt_pointer(const struct bpf_reg_state *reg,
1933 				    enum bpf_reg_type which)
1934 {
1935 	/* The register can already have a range from prior markings.
1936 	 * This is fine as long as it hasn't been advanced from its
1937 	 * origin.
1938 	 */
1939 	return reg->type == which &&
1940 	       reg->id == 0 &&
1941 	       reg->off == 0 &&
1942 	       tnum_equals_const(reg->var_off, 0);
1943 }
1944 
1945 /* Reset the min/max bounds of a register */
1946 static void __mark_reg_unbounded(struct bpf_reg_state *reg)
1947 {
1948 	reg->smin_value = S64_MIN;
1949 	reg->smax_value = S64_MAX;
1950 	reg->umin_value = 0;
1951 	reg->umax_value = U64_MAX;
1952 
1953 	reg->s32_min_value = S32_MIN;
1954 	reg->s32_max_value = S32_MAX;
1955 	reg->u32_min_value = 0;
1956 	reg->u32_max_value = U32_MAX;
1957 }
1958 
1959 static void __mark_reg64_unbounded(struct bpf_reg_state *reg)
1960 {
1961 	reg->smin_value = S64_MIN;
1962 	reg->smax_value = S64_MAX;
1963 	reg->umin_value = 0;
1964 	reg->umax_value = U64_MAX;
1965 }
1966 
1967 static void __mark_reg32_unbounded(struct bpf_reg_state *reg)
1968 {
1969 	reg->s32_min_value = S32_MIN;
1970 	reg->s32_max_value = S32_MAX;
1971 	reg->u32_min_value = 0;
1972 	reg->u32_max_value = U32_MAX;
1973 }
1974 
1975 static void __update_reg32_bounds(struct bpf_reg_state *reg)
1976 {
1977 	struct tnum var32_off = tnum_subreg(reg->var_off);
1978 
1979 	/* min signed is max(sign bit) | min(other bits) */
1980 	reg->s32_min_value = max_t(s32, reg->s32_min_value,
1981 			var32_off.value | (var32_off.mask & S32_MIN));
1982 	/* max signed is min(sign bit) | max(other bits) */
1983 	reg->s32_max_value = min_t(s32, reg->s32_max_value,
1984 			var32_off.value | (var32_off.mask & S32_MAX));
1985 	reg->u32_min_value = max_t(u32, reg->u32_min_value, (u32)var32_off.value);
1986 	reg->u32_max_value = min(reg->u32_max_value,
1987 				 (u32)(var32_off.value | var32_off.mask));
1988 }
1989 
1990 static void __update_reg64_bounds(struct bpf_reg_state *reg)
1991 {
1992 	/* min signed is max(sign bit) | min(other bits) */
1993 	reg->smin_value = max_t(s64, reg->smin_value,
1994 				reg->var_off.value | (reg->var_off.mask & S64_MIN));
1995 	/* max signed is min(sign bit) | max(other bits) */
1996 	reg->smax_value = min_t(s64, reg->smax_value,
1997 				reg->var_off.value | (reg->var_off.mask & S64_MAX));
1998 	reg->umin_value = max(reg->umin_value, reg->var_off.value);
1999 	reg->umax_value = min(reg->umax_value,
2000 			      reg->var_off.value | reg->var_off.mask);
2001 }
2002 
2003 static void __update_reg_bounds(struct bpf_reg_state *reg)
2004 {
2005 	__update_reg32_bounds(reg);
2006 	__update_reg64_bounds(reg);
2007 }
2008 
2009 /* Uses signed min/max values to inform unsigned, and vice-versa */
2010 static void __reg32_deduce_bounds(struct bpf_reg_state *reg)
2011 {
2012 	/* Learn sign from signed bounds.
2013 	 * If we cannot cross the sign boundary, then signed and unsigned bounds
2014 	 * are the same, so combine.  This works even in the negative case, e.g.
2015 	 * -3 s<= x s<= -1 implies 0xf...fd u<= x u<= 0xf...ff.
2016 	 */
2017 	if (reg->s32_min_value >= 0 || reg->s32_max_value < 0) {
2018 		reg->s32_min_value = reg->u32_min_value =
2019 			max_t(u32, reg->s32_min_value, reg->u32_min_value);
2020 		reg->s32_max_value = reg->u32_max_value =
2021 			min_t(u32, reg->s32_max_value, reg->u32_max_value);
2022 		return;
2023 	}
2024 	/* Learn sign from unsigned bounds.  Signed bounds cross the sign
2025 	 * boundary, so we must be careful.
2026 	 */
2027 	if ((s32)reg->u32_max_value >= 0) {
2028 		/* Positive.  We can't learn anything from the smin, but smax
2029 		 * is positive, hence safe.
2030 		 */
2031 		reg->s32_min_value = reg->u32_min_value;
2032 		reg->s32_max_value = reg->u32_max_value =
2033 			min_t(u32, reg->s32_max_value, reg->u32_max_value);
2034 	} else if ((s32)reg->u32_min_value < 0) {
2035 		/* Negative.  We can't learn anything from the smax, but smin
2036 		 * is negative, hence safe.
2037 		 */
2038 		reg->s32_min_value = reg->u32_min_value =
2039 			max_t(u32, reg->s32_min_value, reg->u32_min_value);
2040 		reg->s32_max_value = reg->u32_max_value;
2041 	}
2042 }
2043 
2044 static void __reg64_deduce_bounds(struct bpf_reg_state *reg)
2045 {
2046 	/* Learn sign from signed bounds.
2047 	 * If we cannot cross the sign boundary, then signed and unsigned bounds
2048 	 * are the same, so combine.  This works even in the negative case, e.g.
2049 	 * -3 s<= x s<= -1 implies 0xf...fd u<= x u<= 0xf...ff.
2050 	 */
2051 	if (reg->smin_value >= 0 || reg->smax_value < 0) {
2052 		reg->smin_value = reg->umin_value = max_t(u64, reg->smin_value,
2053 							  reg->umin_value);
2054 		reg->smax_value = reg->umax_value = min_t(u64, reg->smax_value,
2055 							  reg->umax_value);
2056 		return;
2057 	}
2058 	/* Learn sign from unsigned bounds.  Signed bounds cross the sign
2059 	 * boundary, so we must be careful.
2060 	 */
2061 	if ((s64)reg->umax_value >= 0) {
2062 		/* Positive.  We can't learn anything from the smin, but smax
2063 		 * is positive, hence safe.
2064 		 */
2065 		reg->smin_value = reg->umin_value;
2066 		reg->smax_value = reg->umax_value = min_t(u64, reg->smax_value,
2067 							  reg->umax_value);
2068 	} else if ((s64)reg->umin_value < 0) {
2069 		/* Negative.  We can't learn anything from the smax, but smin
2070 		 * is negative, hence safe.
2071 		 */
2072 		reg->smin_value = reg->umin_value = max_t(u64, reg->smin_value,
2073 							  reg->umin_value);
2074 		reg->smax_value = reg->umax_value;
2075 	}
2076 }
2077 
2078 static void __reg_deduce_bounds(struct bpf_reg_state *reg)
2079 {
2080 	__reg32_deduce_bounds(reg);
2081 	__reg64_deduce_bounds(reg);
2082 }
2083 
2084 /* Attempts to improve var_off based on unsigned min/max information */
2085 static void __reg_bound_offset(struct bpf_reg_state *reg)
2086 {
2087 	struct tnum var64_off = tnum_intersect(reg->var_off,
2088 					       tnum_range(reg->umin_value,
2089 							  reg->umax_value));
2090 	struct tnum var32_off = tnum_intersect(tnum_subreg(var64_off),
2091 					       tnum_range(reg->u32_min_value,
2092 							  reg->u32_max_value));
2093 
2094 	reg->var_off = tnum_or(tnum_clear_subreg(var64_off), var32_off);
2095 }
2096 
2097 static void reg_bounds_sync(struct bpf_reg_state *reg)
2098 {
2099 	/* We might have learned new bounds from the var_off. */
2100 	__update_reg_bounds(reg);
2101 	/* We might have learned something about the sign bit. */
2102 	__reg_deduce_bounds(reg);
2103 	/* We might have learned some bits from the bounds. */
2104 	__reg_bound_offset(reg);
2105 	/* Intersecting with the old var_off might have improved our bounds
2106 	 * slightly, e.g. if umax was 0x7f...f and var_off was (0; 0xf...fc),
2107 	 * then new var_off is (0; 0x7f...fc) which improves our umax.
2108 	 */
2109 	__update_reg_bounds(reg);
2110 }
2111 
2112 static bool __reg32_bound_s64(s32 a)
2113 {
2114 	return a >= 0 && a <= S32_MAX;
2115 }
2116 
2117 static void __reg_assign_32_into_64(struct bpf_reg_state *reg)
2118 {
2119 	reg->umin_value = reg->u32_min_value;
2120 	reg->umax_value = reg->u32_max_value;
2121 
2122 	/* Attempt to pull 32-bit signed bounds into 64-bit bounds but must
2123 	 * be positive otherwise set to worse case bounds and refine later
2124 	 * from tnum.
2125 	 */
2126 	if (__reg32_bound_s64(reg->s32_min_value) &&
2127 	    __reg32_bound_s64(reg->s32_max_value)) {
2128 		reg->smin_value = reg->s32_min_value;
2129 		reg->smax_value = reg->s32_max_value;
2130 	} else {
2131 		reg->smin_value = 0;
2132 		reg->smax_value = U32_MAX;
2133 	}
2134 }
2135 
2136 static void __reg_combine_32_into_64(struct bpf_reg_state *reg)
2137 {
2138 	/* special case when 64-bit register has upper 32-bit register
2139 	 * zeroed. Typically happens after zext or <<32, >>32 sequence
2140 	 * allowing us to use 32-bit bounds directly,
2141 	 */
2142 	if (tnum_equals_const(tnum_clear_subreg(reg->var_off), 0)) {
2143 		__reg_assign_32_into_64(reg);
2144 	} else {
2145 		/* Otherwise the best we can do is push lower 32bit known and
2146 		 * unknown bits into register (var_off set from jmp logic)
2147 		 * then learn as much as possible from the 64-bit tnum
2148 		 * known and unknown bits. The previous smin/smax bounds are
2149 		 * invalid here because of jmp32 compare so mark them unknown
2150 		 * so they do not impact tnum bounds calculation.
2151 		 */
2152 		__mark_reg64_unbounded(reg);
2153 	}
2154 	reg_bounds_sync(reg);
2155 }
2156 
2157 static bool __reg64_bound_s32(s64 a)
2158 {
2159 	return a >= S32_MIN && a <= S32_MAX;
2160 }
2161 
2162 static bool __reg64_bound_u32(u64 a)
2163 {
2164 	return a >= U32_MIN && a <= U32_MAX;
2165 }
2166 
2167 static void __reg_combine_64_into_32(struct bpf_reg_state *reg)
2168 {
2169 	__mark_reg32_unbounded(reg);
2170 	if (__reg64_bound_s32(reg->smin_value) && __reg64_bound_s32(reg->smax_value)) {
2171 		reg->s32_min_value = (s32)reg->smin_value;
2172 		reg->s32_max_value = (s32)reg->smax_value;
2173 	}
2174 	if (__reg64_bound_u32(reg->umin_value) && __reg64_bound_u32(reg->umax_value)) {
2175 		reg->u32_min_value = (u32)reg->umin_value;
2176 		reg->u32_max_value = (u32)reg->umax_value;
2177 	}
2178 	reg_bounds_sync(reg);
2179 }
2180 
2181 /* Mark a register as having a completely unknown (scalar) value. */
2182 static void __mark_reg_unknown(const struct bpf_verifier_env *env,
2183 			       struct bpf_reg_state *reg)
2184 {
2185 	/*
2186 	 * Clear type, off, and union(map_ptr, range) and
2187 	 * padding between 'type' and union
2188 	 */
2189 	memset(reg, 0, offsetof(struct bpf_reg_state, var_off));
2190 	reg->type = SCALAR_VALUE;
2191 	reg->id = 0;
2192 	reg->ref_obj_id = 0;
2193 	reg->var_off = tnum_unknown;
2194 	reg->frameno = 0;
2195 	reg->precise = !env->bpf_capable;
2196 	__mark_reg_unbounded(reg);
2197 }
2198 
2199 static void mark_reg_unknown(struct bpf_verifier_env *env,
2200 			     struct bpf_reg_state *regs, u32 regno)
2201 {
2202 	if (WARN_ON(regno >= MAX_BPF_REG)) {
2203 		verbose(env, "mark_reg_unknown(regs, %u)\n", regno);
2204 		/* Something bad happened, let's kill all regs except FP */
2205 		for (regno = 0; regno < BPF_REG_FP; regno++)
2206 			__mark_reg_not_init(env, regs + regno);
2207 		return;
2208 	}
2209 	__mark_reg_unknown(env, regs + regno);
2210 }
2211 
2212 static void __mark_reg_not_init(const struct bpf_verifier_env *env,
2213 				struct bpf_reg_state *reg)
2214 {
2215 	__mark_reg_unknown(env, reg);
2216 	reg->type = NOT_INIT;
2217 }
2218 
2219 static void mark_reg_not_init(struct bpf_verifier_env *env,
2220 			      struct bpf_reg_state *regs, u32 regno)
2221 {
2222 	if (WARN_ON(regno >= MAX_BPF_REG)) {
2223 		verbose(env, "mark_reg_not_init(regs, %u)\n", regno);
2224 		/* Something bad happened, let's kill all regs except FP */
2225 		for (regno = 0; regno < BPF_REG_FP; regno++)
2226 			__mark_reg_not_init(env, regs + regno);
2227 		return;
2228 	}
2229 	__mark_reg_not_init(env, regs + regno);
2230 }
2231 
2232 static void mark_btf_ld_reg(struct bpf_verifier_env *env,
2233 			    struct bpf_reg_state *regs, u32 regno,
2234 			    enum bpf_reg_type reg_type,
2235 			    struct btf *btf, u32 btf_id,
2236 			    enum bpf_type_flag flag)
2237 {
2238 	if (reg_type == SCALAR_VALUE) {
2239 		mark_reg_unknown(env, regs, regno);
2240 		return;
2241 	}
2242 	mark_reg_known_zero(env, regs, regno);
2243 	regs[regno].type = PTR_TO_BTF_ID | flag;
2244 	regs[regno].btf = btf;
2245 	regs[regno].btf_id = btf_id;
2246 }
2247 
2248 #define DEF_NOT_SUBREG	(0)
2249 static void init_reg_state(struct bpf_verifier_env *env,
2250 			   struct bpf_func_state *state)
2251 {
2252 	struct bpf_reg_state *regs = state->regs;
2253 	int i;
2254 
2255 	for (i = 0; i < MAX_BPF_REG; i++) {
2256 		mark_reg_not_init(env, regs, i);
2257 		regs[i].live = REG_LIVE_NONE;
2258 		regs[i].parent = NULL;
2259 		regs[i].subreg_def = DEF_NOT_SUBREG;
2260 	}
2261 
2262 	/* frame pointer */
2263 	regs[BPF_REG_FP].type = PTR_TO_STACK;
2264 	mark_reg_known_zero(env, regs, BPF_REG_FP);
2265 	regs[BPF_REG_FP].frameno = state->frameno;
2266 }
2267 
2268 #define BPF_MAIN_FUNC (-1)
2269 static void init_func_state(struct bpf_verifier_env *env,
2270 			    struct bpf_func_state *state,
2271 			    int callsite, int frameno, int subprogno)
2272 {
2273 	state->callsite = callsite;
2274 	state->frameno = frameno;
2275 	state->subprogno = subprogno;
2276 	state->callback_ret_range = tnum_range(0, 0);
2277 	init_reg_state(env, state);
2278 	mark_verifier_state_scratched(env);
2279 }
2280 
2281 /* Similar to push_stack(), but for async callbacks */
2282 static struct bpf_verifier_state *push_async_cb(struct bpf_verifier_env *env,
2283 						int insn_idx, int prev_insn_idx,
2284 						int subprog)
2285 {
2286 	struct bpf_verifier_stack_elem *elem;
2287 	struct bpf_func_state *frame;
2288 
2289 	elem = kzalloc(sizeof(struct bpf_verifier_stack_elem), GFP_KERNEL);
2290 	if (!elem)
2291 		goto err;
2292 
2293 	elem->insn_idx = insn_idx;
2294 	elem->prev_insn_idx = prev_insn_idx;
2295 	elem->next = env->head;
2296 	elem->log_pos = env->log.end_pos;
2297 	env->head = elem;
2298 	env->stack_size++;
2299 	if (env->stack_size > BPF_COMPLEXITY_LIMIT_JMP_SEQ) {
2300 		verbose(env,
2301 			"The sequence of %d jumps is too complex for async cb.\n",
2302 			env->stack_size);
2303 		goto err;
2304 	}
2305 	/* Unlike push_stack() do not copy_verifier_state().
2306 	 * The caller state doesn't matter.
2307 	 * This is async callback. It starts in a fresh stack.
2308 	 * Initialize it similar to do_check_common().
2309 	 */
2310 	elem->st.branches = 1;
2311 	frame = kzalloc(sizeof(*frame), GFP_KERNEL);
2312 	if (!frame)
2313 		goto err;
2314 	init_func_state(env, frame,
2315 			BPF_MAIN_FUNC /* callsite */,
2316 			0 /* frameno within this callchain */,
2317 			subprog /* subprog number within this prog */);
2318 	elem->st.frame[0] = frame;
2319 	return &elem->st;
2320 err:
2321 	free_verifier_state(env->cur_state, true);
2322 	env->cur_state = NULL;
2323 	/* pop all elements and return */
2324 	while (!pop_stack(env, NULL, NULL, false));
2325 	return NULL;
2326 }
2327 
2328 
2329 enum reg_arg_type {
2330 	SRC_OP,		/* register is used as source operand */
2331 	DST_OP,		/* register is used as destination operand */
2332 	DST_OP_NO_MARK	/* same as above, check only, don't mark */
2333 };
2334 
2335 static int cmp_subprogs(const void *a, const void *b)
2336 {
2337 	return ((struct bpf_subprog_info *)a)->start -
2338 	       ((struct bpf_subprog_info *)b)->start;
2339 }
2340 
2341 static int find_subprog(struct bpf_verifier_env *env, int off)
2342 {
2343 	struct bpf_subprog_info *p;
2344 
2345 	p = bsearch(&off, env->subprog_info, env->subprog_cnt,
2346 		    sizeof(env->subprog_info[0]), cmp_subprogs);
2347 	if (!p)
2348 		return -ENOENT;
2349 	return p - env->subprog_info;
2350 
2351 }
2352 
2353 static int add_subprog(struct bpf_verifier_env *env, int off)
2354 {
2355 	int insn_cnt = env->prog->len;
2356 	int ret;
2357 
2358 	if (off >= insn_cnt || off < 0) {
2359 		verbose(env, "call to invalid destination\n");
2360 		return -EINVAL;
2361 	}
2362 	ret = find_subprog(env, off);
2363 	if (ret >= 0)
2364 		return ret;
2365 	if (env->subprog_cnt >= BPF_MAX_SUBPROGS) {
2366 		verbose(env, "too many subprograms\n");
2367 		return -E2BIG;
2368 	}
2369 	/* determine subprog starts. The end is one before the next starts */
2370 	env->subprog_info[env->subprog_cnt++].start = off;
2371 	sort(env->subprog_info, env->subprog_cnt,
2372 	     sizeof(env->subprog_info[0]), cmp_subprogs, NULL);
2373 	return env->subprog_cnt - 1;
2374 }
2375 
2376 #define MAX_KFUNC_DESCS 256
2377 #define MAX_KFUNC_BTFS	256
2378 
2379 struct bpf_kfunc_desc {
2380 	struct btf_func_model func_model;
2381 	u32 func_id;
2382 	s32 imm;
2383 	u16 offset;
2384 	unsigned long addr;
2385 };
2386 
2387 struct bpf_kfunc_btf {
2388 	struct btf *btf;
2389 	struct module *module;
2390 	u16 offset;
2391 };
2392 
2393 struct bpf_kfunc_desc_tab {
2394 	/* Sorted by func_id (BTF ID) and offset (fd_array offset) during
2395 	 * verification. JITs do lookups by bpf_insn, where func_id may not be
2396 	 * available, therefore at the end of verification do_misc_fixups()
2397 	 * sorts this by imm and offset.
2398 	 */
2399 	struct bpf_kfunc_desc descs[MAX_KFUNC_DESCS];
2400 	u32 nr_descs;
2401 };
2402 
2403 struct bpf_kfunc_btf_tab {
2404 	struct bpf_kfunc_btf descs[MAX_KFUNC_BTFS];
2405 	u32 nr_descs;
2406 };
2407 
2408 static int kfunc_desc_cmp_by_id_off(const void *a, const void *b)
2409 {
2410 	const struct bpf_kfunc_desc *d0 = a;
2411 	const struct bpf_kfunc_desc *d1 = b;
2412 
2413 	/* func_id is not greater than BTF_MAX_TYPE */
2414 	return d0->func_id - d1->func_id ?: d0->offset - d1->offset;
2415 }
2416 
2417 static int kfunc_btf_cmp_by_off(const void *a, const void *b)
2418 {
2419 	const struct bpf_kfunc_btf *d0 = a;
2420 	const struct bpf_kfunc_btf *d1 = b;
2421 
2422 	return d0->offset - d1->offset;
2423 }
2424 
2425 static const struct bpf_kfunc_desc *
2426 find_kfunc_desc(const struct bpf_prog *prog, u32 func_id, u16 offset)
2427 {
2428 	struct bpf_kfunc_desc desc = {
2429 		.func_id = func_id,
2430 		.offset = offset,
2431 	};
2432 	struct bpf_kfunc_desc_tab *tab;
2433 
2434 	tab = prog->aux->kfunc_tab;
2435 	return bsearch(&desc, tab->descs, tab->nr_descs,
2436 		       sizeof(tab->descs[0]), kfunc_desc_cmp_by_id_off);
2437 }
2438 
2439 int bpf_get_kfunc_addr(const struct bpf_prog *prog, u32 func_id,
2440 		       u16 btf_fd_idx, u8 **func_addr)
2441 {
2442 	const struct bpf_kfunc_desc *desc;
2443 
2444 	desc = find_kfunc_desc(prog, func_id, btf_fd_idx);
2445 	if (!desc)
2446 		return -EFAULT;
2447 
2448 	*func_addr = (u8 *)desc->addr;
2449 	return 0;
2450 }
2451 
2452 static struct btf *__find_kfunc_desc_btf(struct bpf_verifier_env *env,
2453 					 s16 offset)
2454 {
2455 	struct bpf_kfunc_btf kf_btf = { .offset = offset };
2456 	struct bpf_kfunc_btf_tab *tab;
2457 	struct bpf_kfunc_btf *b;
2458 	struct module *mod;
2459 	struct btf *btf;
2460 	int btf_fd;
2461 
2462 	tab = env->prog->aux->kfunc_btf_tab;
2463 	b = bsearch(&kf_btf, tab->descs, tab->nr_descs,
2464 		    sizeof(tab->descs[0]), kfunc_btf_cmp_by_off);
2465 	if (!b) {
2466 		if (tab->nr_descs == MAX_KFUNC_BTFS) {
2467 			verbose(env, "too many different module BTFs\n");
2468 			return ERR_PTR(-E2BIG);
2469 		}
2470 
2471 		if (bpfptr_is_null(env->fd_array)) {
2472 			verbose(env, "kfunc offset > 0 without fd_array is invalid\n");
2473 			return ERR_PTR(-EPROTO);
2474 		}
2475 
2476 		if (copy_from_bpfptr_offset(&btf_fd, env->fd_array,
2477 					    offset * sizeof(btf_fd),
2478 					    sizeof(btf_fd)))
2479 			return ERR_PTR(-EFAULT);
2480 
2481 		btf = btf_get_by_fd(btf_fd);
2482 		if (IS_ERR(btf)) {
2483 			verbose(env, "invalid module BTF fd specified\n");
2484 			return btf;
2485 		}
2486 
2487 		if (!btf_is_module(btf)) {
2488 			verbose(env, "BTF fd for kfunc is not a module BTF\n");
2489 			btf_put(btf);
2490 			return ERR_PTR(-EINVAL);
2491 		}
2492 
2493 		mod = btf_try_get_module(btf);
2494 		if (!mod) {
2495 			btf_put(btf);
2496 			return ERR_PTR(-ENXIO);
2497 		}
2498 
2499 		b = &tab->descs[tab->nr_descs++];
2500 		b->btf = btf;
2501 		b->module = mod;
2502 		b->offset = offset;
2503 
2504 		sort(tab->descs, tab->nr_descs, sizeof(tab->descs[0]),
2505 		     kfunc_btf_cmp_by_off, NULL);
2506 	}
2507 	return b->btf;
2508 }
2509 
2510 void bpf_free_kfunc_btf_tab(struct bpf_kfunc_btf_tab *tab)
2511 {
2512 	if (!tab)
2513 		return;
2514 
2515 	while (tab->nr_descs--) {
2516 		module_put(tab->descs[tab->nr_descs].module);
2517 		btf_put(tab->descs[tab->nr_descs].btf);
2518 	}
2519 	kfree(tab);
2520 }
2521 
2522 static struct btf *find_kfunc_desc_btf(struct bpf_verifier_env *env, s16 offset)
2523 {
2524 	if (offset) {
2525 		if (offset < 0) {
2526 			/* In the future, this can be allowed to increase limit
2527 			 * of fd index into fd_array, interpreted as u16.
2528 			 */
2529 			verbose(env, "negative offset disallowed for kernel module function call\n");
2530 			return ERR_PTR(-EINVAL);
2531 		}
2532 
2533 		return __find_kfunc_desc_btf(env, offset);
2534 	}
2535 	return btf_vmlinux ?: ERR_PTR(-ENOENT);
2536 }
2537 
2538 static int add_kfunc_call(struct bpf_verifier_env *env, u32 func_id, s16 offset)
2539 {
2540 	const struct btf_type *func, *func_proto;
2541 	struct bpf_kfunc_btf_tab *btf_tab;
2542 	struct bpf_kfunc_desc_tab *tab;
2543 	struct bpf_prog_aux *prog_aux;
2544 	struct bpf_kfunc_desc *desc;
2545 	const char *func_name;
2546 	struct btf *desc_btf;
2547 	unsigned long call_imm;
2548 	unsigned long addr;
2549 	int err;
2550 
2551 	prog_aux = env->prog->aux;
2552 	tab = prog_aux->kfunc_tab;
2553 	btf_tab = prog_aux->kfunc_btf_tab;
2554 	if (!tab) {
2555 		if (!btf_vmlinux) {
2556 			verbose(env, "calling kernel function is not supported without CONFIG_DEBUG_INFO_BTF\n");
2557 			return -ENOTSUPP;
2558 		}
2559 
2560 		if (!env->prog->jit_requested) {
2561 			verbose(env, "JIT is required for calling kernel function\n");
2562 			return -ENOTSUPP;
2563 		}
2564 
2565 		if (!bpf_jit_supports_kfunc_call()) {
2566 			verbose(env, "JIT does not support calling kernel function\n");
2567 			return -ENOTSUPP;
2568 		}
2569 
2570 		if (!env->prog->gpl_compatible) {
2571 			verbose(env, "cannot call kernel function from non-GPL compatible program\n");
2572 			return -EINVAL;
2573 		}
2574 
2575 		tab = kzalloc(sizeof(*tab), GFP_KERNEL);
2576 		if (!tab)
2577 			return -ENOMEM;
2578 		prog_aux->kfunc_tab = tab;
2579 	}
2580 
2581 	/* func_id == 0 is always invalid, but instead of returning an error, be
2582 	 * conservative and wait until the code elimination pass before returning
2583 	 * error, so that invalid calls that get pruned out can be in BPF programs
2584 	 * loaded from userspace.  It is also required that offset be untouched
2585 	 * for such calls.
2586 	 */
2587 	if (!func_id && !offset)
2588 		return 0;
2589 
2590 	if (!btf_tab && offset) {
2591 		btf_tab = kzalloc(sizeof(*btf_tab), GFP_KERNEL);
2592 		if (!btf_tab)
2593 			return -ENOMEM;
2594 		prog_aux->kfunc_btf_tab = btf_tab;
2595 	}
2596 
2597 	desc_btf = find_kfunc_desc_btf(env, offset);
2598 	if (IS_ERR(desc_btf)) {
2599 		verbose(env, "failed to find BTF for kernel function\n");
2600 		return PTR_ERR(desc_btf);
2601 	}
2602 
2603 	if (find_kfunc_desc(env->prog, func_id, offset))
2604 		return 0;
2605 
2606 	if (tab->nr_descs == MAX_KFUNC_DESCS) {
2607 		verbose(env, "too many different kernel function calls\n");
2608 		return -E2BIG;
2609 	}
2610 
2611 	func = btf_type_by_id(desc_btf, func_id);
2612 	if (!func || !btf_type_is_func(func)) {
2613 		verbose(env, "kernel btf_id %u is not a function\n",
2614 			func_id);
2615 		return -EINVAL;
2616 	}
2617 	func_proto = btf_type_by_id(desc_btf, func->type);
2618 	if (!func_proto || !btf_type_is_func_proto(func_proto)) {
2619 		verbose(env, "kernel function btf_id %u does not have a valid func_proto\n",
2620 			func_id);
2621 		return -EINVAL;
2622 	}
2623 
2624 	func_name = btf_name_by_offset(desc_btf, func->name_off);
2625 	addr = kallsyms_lookup_name(func_name);
2626 	if (!addr) {
2627 		verbose(env, "cannot find address for kernel function %s\n",
2628 			func_name);
2629 		return -EINVAL;
2630 	}
2631 	specialize_kfunc(env, func_id, offset, &addr);
2632 
2633 	if (bpf_jit_supports_far_kfunc_call()) {
2634 		call_imm = func_id;
2635 	} else {
2636 		call_imm = BPF_CALL_IMM(addr);
2637 		/* Check whether the relative offset overflows desc->imm */
2638 		if ((unsigned long)(s32)call_imm != call_imm) {
2639 			verbose(env, "address of kernel function %s is out of range\n",
2640 				func_name);
2641 			return -EINVAL;
2642 		}
2643 	}
2644 
2645 	if (bpf_dev_bound_kfunc_id(func_id)) {
2646 		err = bpf_dev_bound_kfunc_check(&env->log, prog_aux);
2647 		if (err)
2648 			return err;
2649 	}
2650 
2651 	desc = &tab->descs[tab->nr_descs++];
2652 	desc->func_id = func_id;
2653 	desc->imm = call_imm;
2654 	desc->offset = offset;
2655 	desc->addr = addr;
2656 	err = btf_distill_func_proto(&env->log, desc_btf,
2657 				     func_proto, func_name,
2658 				     &desc->func_model);
2659 	if (!err)
2660 		sort(tab->descs, tab->nr_descs, sizeof(tab->descs[0]),
2661 		     kfunc_desc_cmp_by_id_off, NULL);
2662 	return err;
2663 }
2664 
2665 static int kfunc_desc_cmp_by_imm_off(const void *a, const void *b)
2666 {
2667 	const struct bpf_kfunc_desc *d0 = a;
2668 	const struct bpf_kfunc_desc *d1 = b;
2669 
2670 	if (d0->imm != d1->imm)
2671 		return d0->imm < d1->imm ? -1 : 1;
2672 	if (d0->offset != d1->offset)
2673 		return d0->offset < d1->offset ? -1 : 1;
2674 	return 0;
2675 }
2676 
2677 static void sort_kfunc_descs_by_imm_off(struct bpf_prog *prog)
2678 {
2679 	struct bpf_kfunc_desc_tab *tab;
2680 
2681 	tab = prog->aux->kfunc_tab;
2682 	if (!tab)
2683 		return;
2684 
2685 	sort(tab->descs, tab->nr_descs, sizeof(tab->descs[0]),
2686 	     kfunc_desc_cmp_by_imm_off, NULL);
2687 }
2688 
2689 bool bpf_prog_has_kfunc_call(const struct bpf_prog *prog)
2690 {
2691 	return !!prog->aux->kfunc_tab;
2692 }
2693 
2694 const struct btf_func_model *
2695 bpf_jit_find_kfunc_model(const struct bpf_prog *prog,
2696 			 const struct bpf_insn *insn)
2697 {
2698 	const struct bpf_kfunc_desc desc = {
2699 		.imm = insn->imm,
2700 		.offset = insn->off,
2701 	};
2702 	const struct bpf_kfunc_desc *res;
2703 	struct bpf_kfunc_desc_tab *tab;
2704 
2705 	tab = prog->aux->kfunc_tab;
2706 	res = bsearch(&desc, tab->descs, tab->nr_descs,
2707 		      sizeof(tab->descs[0]), kfunc_desc_cmp_by_imm_off);
2708 
2709 	return res ? &res->func_model : NULL;
2710 }
2711 
2712 static int add_subprog_and_kfunc(struct bpf_verifier_env *env)
2713 {
2714 	struct bpf_subprog_info *subprog = env->subprog_info;
2715 	struct bpf_insn *insn = env->prog->insnsi;
2716 	int i, ret, insn_cnt = env->prog->len;
2717 
2718 	/* Add entry function. */
2719 	ret = add_subprog(env, 0);
2720 	if (ret)
2721 		return ret;
2722 
2723 	for (i = 0; i < insn_cnt; i++, insn++) {
2724 		if (!bpf_pseudo_func(insn) && !bpf_pseudo_call(insn) &&
2725 		    !bpf_pseudo_kfunc_call(insn))
2726 			continue;
2727 
2728 		if (!env->bpf_capable) {
2729 			verbose(env, "loading/calling other bpf or kernel functions are allowed for CAP_BPF and CAP_SYS_ADMIN\n");
2730 			return -EPERM;
2731 		}
2732 
2733 		if (bpf_pseudo_func(insn) || bpf_pseudo_call(insn))
2734 			ret = add_subprog(env, i + insn->imm + 1);
2735 		else
2736 			ret = add_kfunc_call(env, insn->imm, insn->off);
2737 
2738 		if (ret < 0)
2739 			return ret;
2740 	}
2741 
2742 	/* Add a fake 'exit' subprog which could simplify subprog iteration
2743 	 * logic. 'subprog_cnt' should not be increased.
2744 	 */
2745 	subprog[env->subprog_cnt].start = insn_cnt;
2746 
2747 	if (env->log.level & BPF_LOG_LEVEL2)
2748 		for (i = 0; i < env->subprog_cnt; i++)
2749 			verbose(env, "func#%d @%d\n", i, subprog[i].start);
2750 
2751 	return 0;
2752 }
2753 
2754 static int check_subprogs(struct bpf_verifier_env *env)
2755 {
2756 	int i, subprog_start, subprog_end, off, cur_subprog = 0;
2757 	struct bpf_subprog_info *subprog = env->subprog_info;
2758 	struct bpf_insn *insn = env->prog->insnsi;
2759 	int insn_cnt = env->prog->len;
2760 
2761 	/* now check that all jumps are within the same subprog */
2762 	subprog_start = subprog[cur_subprog].start;
2763 	subprog_end = subprog[cur_subprog + 1].start;
2764 	for (i = 0; i < insn_cnt; i++) {
2765 		u8 code = insn[i].code;
2766 
2767 		if (code == (BPF_JMP | BPF_CALL) &&
2768 		    insn[i].src_reg == 0 &&
2769 		    insn[i].imm == BPF_FUNC_tail_call)
2770 			subprog[cur_subprog].has_tail_call = true;
2771 		if (BPF_CLASS(code) == BPF_LD &&
2772 		    (BPF_MODE(code) == BPF_ABS || BPF_MODE(code) == BPF_IND))
2773 			subprog[cur_subprog].has_ld_abs = true;
2774 		if (BPF_CLASS(code) != BPF_JMP && BPF_CLASS(code) != BPF_JMP32)
2775 			goto next;
2776 		if (BPF_OP(code) == BPF_EXIT || BPF_OP(code) == BPF_CALL)
2777 			goto next;
2778 		off = i + insn[i].off + 1;
2779 		if (off < subprog_start || off >= subprog_end) {
2780 			verbose(env, "jump out of range from insn %d to %d\n", i, off);
2781 			return -EINVAL;
2782 		}
2783 next:
2784 		if (i == subprog_end - 1) {
2785 			/* to avoid fall-through from one subprog into another
2786 			 * the last insn of the subprog should be either exit
2787 			 * or unconditional jump back
2788 			 */
2789 			if (code != (BPF_JMP | BPF_EXIT) &&
2790 			    code != (BPF_JMP | BPF_JA)) {
2791 				verbose(env, "last insn is not an exit or jmp\n");
2792 				return -EINVAL;
2793 			}
2794 			subprog_start = subprog_end;
2795 			cur_subprog++;
2796 			if (cur_subprog < env->subprog_cnt)
2797 				subprog_end = subprog[cur_subprog + 1].start;
2798 		}
2799 	}
2800 	return 0;
2801 }
2802 
2803 /* Parentage chain of this register (or stack slot) should take care of all
2804  * issues like callee-saved registers, stack slot allocation time, etc.
2805  */
2806 static int mark_reg_read(struct bpf_verifier_env *env,
2807 			 const struct bpf_reg_state *state,
2808 			 struct bpf_reg_state *parent, u8 flag)
2809 {
2810 	bool writes = parent == state->parent; /* Observe write marks */
2811 	int cnt = 0;
2812 
2813 	while (parent) {
2814 		/* if read wasn't screened by an earlier write ... */
2815 		if (writes && state->live & REG_LIVE_WRITTEN)
2816 			break;
2817 		if (parent->live & REG_LIVE_DONE) {
2818 			verbose(env, "verifier BUG type %s var_off %lld off %d\n",
2819 				reg_type_str(env, parent->type),
2820 				parent->var_off.value, parent->off);
2821 			return -EFAULT;
2822 		}
2823 		/* The first condition is more likely to be true than the
2824 		 * second, checked it first.
2825 		 */
2826 		if ((parent->live & REG_LIVE_READ) == flag ||
2827 		    parent->live & REG_LIVE_READ64)
2828 			/* The parentage chain never changes and
2829 			 * this parent was already marked as LIVE_READ.
2830 			 * There is no need to keep walking the chain again and
2831 			 * keep re-marking all parents as LIVE_READ.
2832 			 * This case happens when the same register is read
2833 			 * multiple times without writes into it in-between.
2834 			 * Also, if parent has the stronger REG_LIVE_READ64 set,
2835 			 * then no need to set the weak REG_LIVE_READ32.
2836 			 */
2837 			break;
2838 		/* ... then we depend on parent's value */
2839 		parent->live |= flag;
2840 		/* REG_LIVE_READ64 overrides REG_LIVE_READ32. */
2841 		if (flag == REG_LIVE_READ64)
2842 			parent->live &= ~REG_LIVE_READ32;
2843 		state = parent;
2844 		parent = state->parent;
2845 		writes = true;
2846 		cnt++;
2847 	}
2848 
2849 	if (env->longest_mark_read_walk < cnt)
2850 		env->longest_mark_read_walk = cnt;
2851 	return 0;
2852 }
2853 
2854 static int mark_dynptr_read(struct bpf_verifier_env *env, struct bpf_reg_state *reg)
2855 {
2856 	struct bpf_func_state *state = func(env, reg);
2857 	int spi, ret;
2858 
2859 	/* For CONST_PTR_TO_DYNPTR, it must have already been done by
2860 	 * check_reg_arg in check_helper_call and mark_btf_func_reg_size in
2861 	 * check_kfunc_call.
2862 	 */
2863 	if (reg->type == CONST_PTR_TO_DYNPTR)
2864 		return 0;
2865 	spi = dynptr_get_spi(env, reg);
2866 	if (spi < 0)
2867 		return spi;
2868 	/* Caller ensures dynptr is valid and initialized, which means spi is in
2869 	 * bounds and spi is the first dynptr slot. Simply mark stack slot as
2870 	 * read.
2871 	 */
2872 	ret = mark_reg_read(env, &state->stack[spi].spilled_ptr,
2873 			    state->stack[spi].spilled_ptr.parent, REG_LIVE_READ64);
2874 	if (ret)
2875 		return ret;
2876 	return mark_reg_read(env, &state->stack[spi - 1].spilled_ptr,
2877 			     state->stack[spi - 1].spilled_ptr.parent, REG_LIVE_READ64);
2878 }
2879 
2880 static int mark_iter_read(struct bpf_verifier_env *env, struct bpf_reg_state *reg,
2881 			  int spi, int nr_slots)
2882 {
2883 	struct bpf_func_state *state = func(env, reg);
2884 	int err, i;
2885 
2886 	for (i = 0; i < nr_slots; i++) {
2887 		struct bpf_reg_state *st = &state->stack[spi - i].spilled_ptr;
2888 
2889 		err = mark_reg_read(env, st, st->parent, REG_LIVE_READ64);
2890 		if (err)
2891 			return err;
2892 
2893 		mark_stack_slot_scratched(env, spi - i);
2894 	}
2895 
2896 	return 0;
2897 }
2898 
2899 /* This function is supposed to be used by the following 32-bit optimization
2900  * code only. It returns TRUE if the source or destination register operates
2901  * on 64-bit, otherwise return FALSE.
2902  */
2903 static bool is_reg64(struct bpf_verifier_env *env, struct bpf_insn *insn,
2904 		     u32 regno, struct bpf_reg_state *reg, enum reg_arg_type t)
2905 {
2906 	u8 code, class, op;
2907 
2908 	code = insn->code;
2909 	class = BPF_CLASS(code);
2910 	op = BPF_OP(code);
2911 	if (class == BPF_JMP) {
2912 		/* BPF_EXIT for "main" will reach here. Return TRUE
2913 		 * conservatively.
2914 		 */
2915 		if (op == BPF_EXIT)
2916 			return true;
2917 		if (op == BPF_CALL) {
2918 			/* BPF to BPF call will reach here because of marking
2919 			 * caller saved clobber with DST_OP_NO_MARK for which we
2920 			 * don't care the register def because they are anyway
2921 			 * marked as NOT_INIT already.
2922 			 */
2923 			if (insn->src_reg == BPF_PSEUDO_CALL)
2924 				return false;
2925 			/* Helper call will reach here because of arg type
2926 			 * check, conservatively return TRUE.
2927 			 */
2928 			if (t == SRC_OP)
2929 				return true;
2930 
2931 			return false;
2932 		}
2933 	}
2934 
2935 	if (class == BPF_ALU64 || class == BPF_JMP ||
2936 	    /* BPF_END always use BPF_ALU class. */
2937 	    (class == BPF_ALU && op == BPF_END && insn->imm == 64))
2938 		return true;
2939 
2940 	if (class == BPF_ALU || class == BPF_JMP32)
2941 		return false;
2942 
2943 	if (class == BPF_LDX) {
2944 		if (t != SRC_OP)
2945 			return BPF_SIZE(code) == BPF_DW;
2946 		/* LDX source must be ptr. */
2947 		return true;
2948 	}
2949 
2950 	if (class == BPF_STX) {
2951 		/* BPF_STX (including atomic variants) has multiple source
2952 		 * operands, one of which is a ptr. Check whether the caller is
2953 		 * asking about it.
2954 		 */
2955 		if (t == SRC_OP && reg->type != SCALAR_VALUE)
2956 			return true;
2957 		return BPF_SIZE(code) == BPF_DW;
2958 	}
2959 
2960 	if (class == BPF_LD) {
2961 		u8 mode = BPF_MODE(code);
2962 
2963 		/* LD_IMM64 */
2964 		if (mode == BPF_IMM)
2965 			return true;
2966 
2967 		/* Both LD_IND and LD_ABS return 32-bit data. */
2968 		if (t != SRC_OP)
2969 			return  false;
2970 
2971 		/* Implicit ctx ptr. */
2972 		if (regno == BPF_REG_6)
2973 			return true;
2974 
2975 		/* Explicit source could be any width. */
2976 		return true;
2977 	}
2978 
2979 	if (class == BPF_ST)
2980 		/* The only source register for BPF_ST is a ptr. */
2981 		return true;
2982 
2983 	/* Conservatively return true at default. */
2984 	return true;
2985 }
2986 
2987 /* Return the regno defined by the insn, or -1. */
2988 static int insn_def_regno(const struct bpf_insn *insn)
2989 {
2990 	switch (BPF_CLASS(insn->code)) {
2991 	case BPF_JMP:
2992 	case BPF_JMP32:
2993 	case BPF_ST:
2994 		return -1;
2995 	case BPF_STX:
2996 		if (BPF_MODE(insn->code) == BPF_ATOMIC &&
2997 		    (insn->imm & BPF_FETCH)) {
2998 			if (insn->imm == BPF_CMPXCHG)
2999 				return BPF_REG_0;
3000 			else
3001 				return insn->src_reg;
3002 		} else {
3003 			return -1;
3004 		}
3005 	default:
3006 		return insn->dst_reg;
3007 	}
3008 }
3009 
3010 /* Return TRUE if INSN has defined any 32-bit value explicitly. */
3011 static bool insn_has_def32(struct bpf_verifier_env *env, struct bpf_insn *insn)
3012 {
3013 	int dst_reg = insn_def_regno(insn);
3014 
3015 	if (dst_reg == -1)
3016 		return false;
3017 
3018 	return !is_reg64(env, insn, dst_reg, NULL, DST_OP);
3019 }
3020 
3021 static void mark_insn_zext(struct bpf_verifier_env *env,
3022 			   struct bpf_reg_state *reg)
3023 {
3024 	s32 def_idx = reg->subreg_def;
3025 
3026 	if (def_idx == DEF_NOT_SUBREG)
3027 		return;
3028 
3029 	env->insn_aux_data[def_idx - 1].zext_dst = true;
3030 	/* The dst will be zero extended, so won't be sub-register anymore. */
3031 	reg->subreg_def = DEF_NOT_SUBREG;
3032 }
3033 
3034 static int check_reg_arg(struct bpf_verifier_env *env, u32 regno,
3035 			 enum reg_arg_type t)
3036 {
3037 	struct bpf_verifier_state *vstate = env->cur_state;
3038 	struct bpf_func_state *state = vstate->frame[vstate->curframe];
3039 	struct bpf_insn *insn = env->prog->insnsi + env->insn_idx;
3040 	struct bpf_reg_state *reg, *regs = state->regs;
3041 	bool rw64;
3042 
3043 	if (regno >= MAX_BPF_REG) {
3044 		verbose(env, "R%d is invalid\n", regno);
3045 		return -EINVAL;
3046 	}
3047 
3048 	mark_reg_scratched(env, regno);
3049 
3050 	reg = &regs[regno];
3051 	rw64 = is_reg64(env, insn, regno, reg, t);
3052 	if (t == SRC_OP) {
3053 		/* check whether register used as source operand can be read */
3054 		if (reg->type == NOT_INIT) {
3055 			verbose(env, "R%d !read_ok\n", regno);
3056 			return -EACCES;
3057 		}
3058 		/* We don't need to worry about FP liveness because it's read-only */
3059 		if (regno == BPF_REG_FP)
3060 			return 0;
3061 
3062 		if (rw64)
3063 			mark_insn_zext(env, reg);
3064 
3065 		return mark_reg_read(env, reg, reg->parent,
3066 				     rw64 ? REG_LIVE_READ64 : REG_LIVE_READ32);
3067 	} else {
3068 		/* check whether register used as dest operand can be written to */
3069 		if (regno == BPF_REG_FP) {
3070 			verbose(env, "frame pointer is read only\n");
3071 			return -EACCES;
3072 		}
3073 		reg->live |= REG_LIVE_WRITTEN;
3074 		reg->subreg_def = rw64 ? DEF_NOT_SUBREG : env->insn_idx + 1;
3075 		if (t == DST_OP)
3076 			mark_reg_unknown(env, regs, regno);
3077 	}
3078 	return 0;
3079 }
3080 
3081 static void mark_jmp_point(struct bpf_verifier_env *env, int idx)
3082 {
3083 	env->insn_aux_data[idx].jmp_point = true;
3084 }
3085 
3086 static bool is_jmp_point(struct bpf_verifier_env *env, int insn_idx)
3087 {
3088 	return env->insn_aux_data[insn_idx].jmp_point;
3089 }
3090 
3091 /* for any branch, call, exit record the history of jmps in the given state */
3092 static int push_jmp_history(struct bpf_verifier_env *env,
3093 			    struct bpf_verifier_state *cur)
3094 {
3095 	u32 cnt = cur->jmp_history_cnt;
3096 	struct bpf_idx_pair *p;
3097 	size_t alloc_size;
3098 
3099 	if (!is_jmp_point(env, env->insn_idx))
3100 		return 0;
3101 
3102 	cnt++;
3103 	alloc_size = kmalloc_size_roundup(size_mul(cnt, sizeof(*p)));
3104 	p = krealloc(cur->jmp_history, alloc_size, GFP_USER);
3105 	if (!p)
3106 		return -ENOMEM;
3107 	p[cnt - 1].idx = env->insn_idx;
3108 	p[cnt - 1].prev_idx = env->prev_insn_idx;
3109 	cur->jmp_history = p;
3110 	cur->jmp_history_cnt = cnt;
3111 	return 0;
3112 }
3113 
3114 /* Backtrack one insn at a time. If idx is not at the top of recorded
3115  * history then previous instruction came from straight line execution.
3116  */
3117 static int get_prev_insn_idx(struct bpf_verifier_state *st, int i,
3118 			     u32 *history)
3119 {
3120 	u32 cnt = *history;
3121 
3122 	if (cnt && st->jmp_history[cnt - 1].idx == i) {
3123 		i = st->jmp_history[cnt - 1].prev_idx;
3124 		(*history)--;
3125 	} else {
3126 		i--;
3127 	}
3128 	return i;
3129 }
3130 
3131 static const char *disasm_kfunc_name(void *data, const struct bpf_insn *insn)
3132 {
3133 	const struct btf_type *func;
3134 	struct btf *desc_btf;
3135 
3136 	if (insn->src_reg != BPF_PSEUDO_KFUNC_CALL)
3137 		return NULL;
3138 
3139 	desc_btf = find_kfunc_desc_btf(data, insn->off);
3140 	if (IS_ERR(desc_btf))
3141 		return "<error>";
3142 
3143 	func = btf_type_by_id(desc_btf, insn->imm);
3144 	return btf_name_by_offset(desc_btf, func->name_off);
3145 }
3146 
3147 /* For given verifier state backtrack_insn() is called from the last insn to
3148  * the first insn. Its purpose is to compute a bitmask of registers and
3149  * stack slots that needs precision in the parent verifier state.
3150  */
3151 static int backtrack_insn(struct bpf_verifier_env *env, int idx,
3152 			  u32 *reg_mask, u64 *stack_mask)
3153 {
3154 	const struct bpf_insn_cbs cbs = {
3155 		.cb_call	= disasm_kfunc_name,
3156 		.cb_print	= verbose,
3157 		.private_data	= env,
3158 	};
3159 	struct bpf_insn *insn = env->prog->insnsi + idx;
3160 	u8 class = BPF_CLASS(insn->code);
3161 	u8 opcode = BPF_OP(insn->code);
3162 	u8 mode = BPF_MODE(insn->code);
3163 	u32 dreg = 1u << insn->dst_reg;
3164 	u32 sreg = 1u << insn->src_reg;
3165 	u32 spi;
3166 
3167 	if (insn->code == 0)
3168 		return 0;
3169 	if (env->log.level & BPF_LOG_LEVEL2) {
3170 		verbose(env, "regs=%x stack=%llx before ", *reg_mask, *stack_mask);
3171 		verbose(env, "%d: ", idx);
3172 		print_bpf_insn(&cbs, insn, env->allow_ptr_leaks);
3173 	}
3174 
3175 	if (class == BPF_ALU || class == BPF_ALU64) {
3176 		if (!(*reg_mask & dreg))
3177 			return 0;
3178 		if (opcode == BPF_MOV) {
3179 			if (BPF_SRC(insn->code) == BPF_X) {
3180 				/* dreg = sreg
3181 				 * dreg needs precision after this insn
3182 				 * sreg needs precision before this insn
3183 				 */
3184 				*reg_mask &= ~dreg;
3185 				*reg_mask |= sreg;
3186 			} else {
3187 				/* dreg = K
3188 				 * dreg needs precision after this insn.
3189 				 * Corresponding register is already marked
3190 				 * as precise=true in this verifier state.
3191 				 * No further markings in parent are necessary
3192 				 */
3193 				*reg_mask &= ~dreg;
3194 			}
3195 		} else {
3196 			if (BPF_SRC(insn->code) == BPF_X) {
3197 				/* dreg += sreg
3198 				 * both dreg and sreg need precision
3199 				 * before this insn
3200 				 */
3201 				*reg_mask |= sreg;
3202 			} /* else dreg += K
3203 			   * dreg still needs precision before this insn
3204 			   */
3205 		}
3206 	} else if (class == BPF_LDX) {
3207 		if (!(*reg_mask & dreg))
3208 			return 0;
3209 		*reg_mask &= ~dreg;
3210 
3211 		/* scalars can only be spilled into stack w/o losing precision.
3212 		 * Load from any other memory can be zero extended.
3213 		 * The desire to keep that precision is already indicated
3214 		 * by 'precise' mark in corresponding register of this state.
3215 		 * No further tracking necessary.
3216 		 */
3217 		if (insn->src_reg != BPF_REG_FP)
3218 			return 0;
3219 
3220 		/* dreg = *(u64 *)[fp - off] was a fill from the stack.
3221 		 * that [fp - off] slot contains scalar that needs to be
3222 		 * tracked with precision
3223 		 */
3224 		spi = (-insn->off - 1) / BPF_REG_SIZE;
3225 		if (spi >= 64) {
3226 			verbose(env, "BUG spi %d\n", spi);
3227 			WARN_ONCE(1, "verifier backtracking bug");
3228 			return -EFAULT;
3229 		}
3230 		*stack_mask |= 1ull << spi;
3231 	} else if (class == BPF_STX || class == BPF_ST) {
3232 		if (*reg_mask & dreg)
3233 			/* stx & st shouldn't be using _scalar_ dst_reg
3234 			 * to access memory. It means backtracking
3235 			 * encountered a case of pointer subtraction.
3236 			 */
3237 			return -ENOTSUPP;
3238 		/* scalars can only be spilled into stack */
3239 		if (insn->dst_reg != BPF_REG_FP)
3240 			return 0;
3241 		spi = (-insn->off - 1) / BPF_REG_SIZE;
3242 		if (spi >= 64) {
3243 			verbose(env, "BUG spi %d\n", spi);
3244 			WARN_ONCE(1, "verifier backtracking bug");
3245 			return -EFAULT;
3246 		}
3247 		if (!(*stack_mask & (1ull << spi)))
3248 			return 0;
3249 		*stack_mask &= ~(1ull << spi);
3250 		if (class == BPF_STX)
3251 			*reg_mask |= sreg;
3252 	} else if (class == BPF_JMP || class == BPF_JMP32) {
3253 		if (opcode == BPF_CALL) {
3254 			if (insn->src_reg == BPF_PSEUDO_CALL)
3255 				return -ENOTSUPP;
3256 			/* BPF helpers that invoke callback subprogs are
3257 			 * equivalent to BPF_PSEUDO_CALL above
3258 			 */
3259 			if (insn->src_reg == 0 && is_callback_calling_function(insn->imm))
3260 				return -ENOTSUPP;
3261 			/* kfunc with imm==0 is invalid and fixup_kfunc_call will
3262 			 * catch this error later. Make backtracking conservative
3263 			 * with ENOTSUPP.
3264 			 */
3265 			if (insn->src_reg == BPF_PSEUDO_KFUNC_CALL && insn->imm == 0)
3266 				return -ENOTSUPP;
3267 			/* regular helper call sets R0 */
3268 			*reg_mask &= ~1;
3269 			if (*reg_mask & 0x3f) {
3270 				/* if backtracing was looking for registers R1-R5
3271 				 * they should have been found already.
3272 				 */
3273 				verbose(env, "BUG regs %x\n", *reg_mask);
3274 				WARN_ONCE(1, "verifier backtracking bug");
3275 				return -EFAULT;
3276 			}
3277 		} else if (opcode == BPF_EXIT) {
3278 			return -ENOTSUPP;
3279 		} else if (BPF_SRC(insn->code) == BPF_X) {
3280 			if (!(*reg_mask & (dreg | sreg)))
3281 				return 0;
3282 			/* dreg <cond> sreg
3283 			 * Both dreg and sreg need precision before
3284 			 * this insn. If only sreg was marked precise
3285 			 * before it would be equally necessary to
3286 			 * propagate it to dreg.
3287 			 */
3288 			*reg_mask |= (sreg | dreg);
3289 			 /* else dreg <cond> K
3290 			  * Only dreg still needs precision before
3291 			  * this insn, so for the K-based conditional
3292 			  * there is nothing new to be marked.
3293 			  */
3294 		}
3295 	} else if (class == BPF_LD) {
3296 		if (!(*reg_mask & dreg))
3297 			return 0;
3298 		*reg_mask &= ~dreg;
3299 		/* It's ld_imm64 or ld_abs or ld_ind.
3300 		 * For ld_imm64 no further tracking of precision
3301 		 * into parent is necessary
3302 		 */
3303 		if (mode == BPF_IND || mode == BPF_ABS)
3304 			/* to be analyzed */
3305 			return -ENOTSUPP;
3306 	}
3307 	return 0;
3308 }
3309 
3310 /* the scalar precision tracking algorithm:
3311  * . at the start all registers have precise=false.
3312  * . scalar ranges are tracked as normal through alu and jmp insns.
3313  * . once precise value of the scalar register is used in:
3314  *   .  ptr + scalar alu
3315  *   . if (scalar cond K|scalar)
3316  *   .  helper_call(.., scalar, ...) where ARG_CONST is expected
3317  *   backtrack through the verifier states and mark all registers and
3318  *   stack slots with spilled constants that these scalar regisers
3319  *   should be precise.
3320  * . during state pruning two registers (or spilled stack slots)
3321  *   are equivalent if both are not precise.
3322  *
3323  * Note the verifier cannot simply walk register parentage chain,
3324  * since many different registers and stack slots could have been
3325  * used to compute single precise scalar.
3326  *
3327  * The approach of starting with precise=true for all registers and then
3328  * backtrack to mark a register as not precise when the verifier detects
3329  * that program doesn't care about specific value (e.g., when helper
3330  * takes register as ARG_ANYTHING parameter) is not safe.
3331  *
3332  * It's ok to walk single parentage chain of the verifier states.
3333  * It's possible that this backtracking will go all the way till 1st insn.
3334  * All other branches will be explored for needing precision later.
3335  *
3336  * The backtracking needs to deal with cases like:
3337  *   R8=map_value(id=0,off=0,ks=4,vs=1952,imm=0) R9_w=map_value(id=0,off=40,ks=4,vs=1952,imm=0)
3338  * r9 -= r8
3339  * r5 = r9
3340  * if r5 > 0x79f goto pc+7
3341  *    R5_w=inv(id=0,umax_value=1951,var_off=(0x0; 0x7ff))
3342  * r5 += 1
3343  * ...
3344  * call bpf_perf_event_output#25
3345  *   where .arg5_type = ARG_CONST_SIZE_OR_ZERO
3346  *
3347  * and this case:
3348  * r6 = 1
3349  * call foo // uses callee's r6 inside to compute r0
3350  * r0 += r6
3351  * if r0 == 0 goto
3352  *
3353  * to track above reg_mask/stack_mask needs to be independent for each frame.
3354  *
3355  * Also if parent's curframe > frame where backtracking started,
3356  * the verifier need to mark registers in both frames, otherwise callees
3357  * may incorrectly prune callers. This is similar to
3358  * commit 7640ead93924 ("bpf: verifier: make sure callees don't prune with caller differences")
3359  *
3360  * For now backtracking falls back into conservative marking.
3361  */
3362 static void mark_all_scalars_precise(struct bpf_verifier_env *env,
3363 				     struct bpf_verifier_state *st)
3364 {
3365 	struct bpf_func_state *func;
3366 	struct bpf_reg_state *reg;
3367 	int i, j;
3368 
3369 	/* big hammer: mark all scalars precise in this path.
3370 	 * pop_stack may still get !precise scalars.
3371 	 * We also skip current state and go straight to first parent state,
3372 	 * because precision markings in current non-checkpointed state are
3373 	 * not needed. See why in the comment in __mark_chain_precision below.
3374 	 */
3375 	for (st = st->parent; st; st = st->parent) {
3376 		for (i = 0; i <= st->curframe; i++) {
3377 			func = st->frame[i];
3378 			for (j = 0; j < BPF_REG_FP; j++) {
3379 				reg = &func->regs[j];
3380 				if (reg->type != SCALAR_VALUE)
3381 					continue;
3382 				reg->precise = true;
3383 			}
3384 			for (j = 0; j < func->allocated_stack / BPF_REG_SIZE; j++) {
3385 				if (!is_spilled_reg(&func->stack[j]))
3386 					continue;
3387 				reg = &func->stack[j].spilled_ptr;
3388 				if (reg->type != SCALAR_VALUE)
3389 					continue;
3390 				reg->precise = true;
3391 			}
3392 		}
3393 	}
3394 }
3395 
3396 static void mark_all_scalars_imprecise(struct bpf_verifier_env *env, struct bpf_verifier_state *st)
3397 {
3398 	struct bpf_func_state *func;
3399 	struct bpf_reg_state *reg;
3400 	int i, j;
3401 
3402 	for (i = 0; i <= st->curframe; i++) {
3403 		func = st->frame[i];
3404 		for (j = 0; j < BPF_REG_FP; j++) {
3405 			reg = &func->regs[j];
3406 			if (reg->type != SCALAR_VALUE)
3407 				continue;
3408 			reg->precise = false;
3409 		}
3410 		for (j = 0; j < func->allocated_stack / BPF_REG_SIZE; j++) {
3411 			if (!is_spilled_reg(&func->stack[j]))
3412 				continue;
3413 			reg = &func->stack[j].spilled_ptr;
3414 			if (reg->type != SCALAR_VALUE)
3415 				continue;
3416 			reg->precise = false;
3417 		}
3418 	}
3419 }
3420 
3421 /*
3422  * __mark_chain_precision() backtracks BPF program instruction sequence and
3423  * chain of verifier states making sure that register *regno* (if regno >= 0)
3424  * and/or stack slot *spi* (if spi >= 0) are marked as precisely tracked
3425  * SCALARS, as well as any other registers and slots that contribute to
3426  * a tracked state of given registers/stack slots, depending on specific BPF
3427  * assembly instructions (see backtrack_insns() for exact instruction handling
3428  * logic). This backtracking relies on recorded jmp_history and is able to
3429  * traverse entire chain of parent states. This process ends only when all the
3430  * necessary registers/slots and their transitive dependencies are marked as
3431  * precise.
3432  *
3433  * One important and subtle aspect is that precise marks *do not matter* in
3434  * the currently verified state (current state). It is important to understand
3435  * why this is the case.
3436  *
3437  * First, note that current state is the state that is not yet "checkpointed",
3438  * i.e., it is not yet put into env->explored_states, and it has no children
3439  * states as well. It's ephemeral, and can end up either a) being discarded if
3440  * compatible explored state is found at some point or BPF_EXIT instruction is
3441  * reached or b) checkpointed and put into env->explored_states, branching out
3442  * into one or more children states.
3443  *
3444  * In the former case, precise markings in current state are completely
3445  * ignored by state comparison code (see regsafe() for details). Only
3446  * checkpointed ("old") state precise markings are important, and if old
3447  * state's register/slot is precise, regsafe() assumes current state's
3448  * register/slot as precise and checks value ranges exactly and precisely. If
3449  * states turn out to be compatible, current state's necessary precise
3450  * markings and any required parent states' precise markings are enforced
3451  * after the fact with propagate_precision() logic, after the fact. But it's
3452  * important to realize that in this case, even after marking current state
3453  * registers/slots as precise, we immediately discard current state. So what
3454  * actually matters is any of the precise markings propagated into current
3455  * state's parent states, which are always checkpointed (due to b) case above).
3456  * As such, for scenario a) it doesn't matter if current state has precise
3457  * markings set or not.
3458  *
3459  * Now, for the scenario b), checkpointing and forking into child(ren)
3460  * state(s). Note that before current state gets to checkpointing step, any
3461  * processed instruction always assumes precise SCALAR register/slot
3462  * knowledge: if precise value or range is useful to prune jump branch, BPF
3463  * verifier takes this opportunity enthusiastically. Similarly, when
3464  * register's value is used to calculate offset or memory address, exact
3465  * knowledge of SCALAR range is assumed, checked, and enforced. So, similar to
3466  * what we mentioned above about state comparison ignoring precise markings
3467  * during state comparison, BPF verifier ignores and also assumes precise
3468  * markings *at will* during instruction verification process. But as verifier
3469  * assumes precision, it also propagates any precision dependencies across
3470  * parent states, which are not yet finalized, so can be further restricted
3471  * based on new knowledge gained from restrictions enforced by their children
3472  * states. This is so that once those parent states are finalized, i.e., when
3473  * they have no more active children state, state comparison logic in
3474  * is_state_visited() would enforce strict and precise SCALAR ranges, if
3475  * required for correctness.
3476  *
3477  * To build a bit more intuition, note also that once a state is checkpointed,
3478  * the path we took to get to that state is not important. This is crucial
3479  * property for state pruning. When state is checkpointed and finalized at
3480  * some instruction index, it can be correctly and safely used to "short
3481  * circuit" any *compatible* state that reaches exactly the same instruction
3482  * index. I.e., if we jumped to that instruction from a completely different
3483  * code path than original finalized state was derived from, it doesn't
3484  * matter, current state can be discarded because from that instruction
3485  * forward having a compatible state will ensure we will safely reach the
3486  * exit. States describe preconditions for further exploration, but completely
3487  * forget the history of how we got here.
3488  *
3489  * This also means that even if we needed precise SCALAR range to get to
3490  * finalized state, but from that point forward *that same* SCALAR register is
3491  * never used in a precise context (i.e., it's precise value is not needed for
3492  * correctness), it's correct and safe to mark such register as "imprecise"
3493  * (i.e., precise marking set to false). This is what we rely on when we do
3494  * not set precise marking in current state. If no child state requires
3495  * precision for any given SCALAR register, it's safe to dictate that it can
3496  * be imprecise. If any child state does require this register to be precise,
3497  * we'll mark it precise later retroactively during precise markings
3498  * propagation from child state to parent states.
3499  *
3500  * Skipping precise marking setting in current state is a mild version of
3501  * relying on the above observation. But we can utilize this property even
3502  * more aggressively by proactively forgetting any precise marking in the
3503  * current state (which we inherited from the parent state), right before we
3504  * checkpoint it and branch off into new child state. This is done by
3505  * mark_all_scalars_imprecise() to hopefully get more permissive and generic
3506  * finalized states which help in short circuiting more future states.
3507  */
3508 static int __mark_chain_precision(struct bpf_verifier_env *env, int frame, int regno,
3509 				  int spi)
3510 {
3511 	struct bpf_verifier_state *st = env->cur_state;
3512 	int first_idx = st->first_insn_idx;
3513 	int last_idx = env->insn_idx;
3514 	struct bpf_func_state *func;
3515 	struct bpf_reg_state *reg;
3516 	u32 reg_mask = regno >= 0 ? 1u << regno : 0;
3517 	u64 stack_mask = spi >= 0 ? 1ull << spi : 0;
3518 	bool skip_first = true;
3519 	bool new_marks = false;
3520 	int i, err;
3521 
3522 	if (!env->bpf_capable)
3523 		return 0;
3524 
3525 	/* Do sanity checks against current state of register and/or stack
3526 	 * slot, but don't set precise flag in current state, as precision
3527 	 * tracking in the current state is unnecessary.
3528 	 */
3529 	func = st->frame[frame];
3530 	if (regno >= 0) {
3531 		reg = &func->regs[regno];
3532 		if (reg->type != SCALAR_VALUE) {
3533 			WARN_ONCE(1, "backtracing misuse");
3534 			return -EFAULT;
3535 		}
3536 		new_marks = true;
3537 	}
3538 
3539 	while (spi >= 0) {
3540 		if (!is_spilled_reg(&func->stack[spi])) {
3541 			stack_mask = 0;
3542 			break;
3543 		}
3544 		reg = &func->stack[spi].spilled_ptr;
3545 		if (reg->type != SCALAR_VALUE) {
3546 			stack_mask = 0;
3547 			break;
3548 		}
3549 		new_marks = true;
3550 		break;
3551 	}
3552 
3553 	if (!new_marks)
3554 		return 0;
3555 	if (!reg_mask && !stack_mask)
3556 		return 0;
3557 
3558 	for (;;) {
3559 		DECLARE_BITMAP(mask, 64);
3560 		u32 history = st->jmp_history_cnt;
3561 
3562 		if (env->log.level & BPF_LOG_LEVEL2)
3563 			verbose(env, "last_idx %d first_idx %d\n", last_idx, first_idx);
3564 
3565 		if (last_idx < 0) {
3566 			/* we are at the entry into subprog, which
3567 			 * is expected for global funcs, but only if
3568 			 * requested precise registers are R1-R5
3569 			 * (which are global func's input arguments)
3570 			 */
3571 			if (st->curframe == 0 &&
3572 			    st->frame[0]->subprogno > 0 &&
3573 			    st->frame[0]->callsite == BPF_MAIN_FUNC &&
3574 			    stack_mask == 0 && (reg_mask & ~0x3e) == 0) {
3575 				bitmap_from_u64(mask, reg_mask);
3576 				for_each_set_bit(i, mask, 32) {
3577 					reg = &st->frame[0]->regs[i];
3578 					if (reg->type != SCALAR_VALUE) {
3579 						reg_mask &= ~(1u << i);
3580 						continue;
3581 					}
3582 					reg->precise = true;
3583 				}
3584 				return 0;
3585 			}
3586 
3587 			verbose(env, "BUG backtracing func entry subprog %d reg_mask %x stack_mask %llx\n",
3588 				st->frame[0]->subprogno, reg_mask, stack_mask);
3589 			WARN_ONCE(1, "verifier backtracking bug");
3590 			return -EFAULT;
3591 		}
3592 
3593 		for (i = last_idx;;) {
3594 			if (skip_first) {
3595 				err = 0;
3596 				skip_first = false;
3597 			} else {
3598 				err = backtrack_insn(env, i, &reg_mask, &stack_mask);
3599 			}
3600 			if (err == -ENOTSUPP) {
3601 				mark_all_scalars_precise(env, st);
3602 				return 0;
3603 			} else if (err) {
3604 				return err;
3605 			}
3606 			if (!reg_mask && !stack_mask)
3607 				/* Found assignment(s) into tracked register in this state.
3608 				 * Since this state is already marked, just return.
3609 				 * Nothing to be tracked further in the parent state.
3610 				 */
3611 				return 0;
3612 			if (i == first_idx)
3613 				break;
3614 			i = get_prev_insn_idx(st, i, &history);
3615 			if (i >= env->prog->len) {
3616 				/* This can happen if backtracking reached insn 0
3617 				 * and there are still reg_mask or stack_mask
3618 				 * to backtrack.
3619 				 * It means the backtracking missed the spot where
3620 				 * particular register was initialized with a constant.
3621 				 */
3622 				verbose(env, "BUG backtracking idx %d\n", i);
3623 				WARN_ONCE(1, "verifier backtracking bug");
3624 				return -EFAULT;
3625 			}
3626 		}
3627 		st = st->parent;
3628 		if (!st)
3629 			break;
3630 
3631 		new_marks = false;
3632 		func = st->frame[frame];
3633 		bitmap_from_u64(mask, reg_mask);
3634 		for_each_set_bit(i, mask, 32) {
3635 			reg = &func->regs[i];
3636 			if (reg->type != SCALAR_VALUE) {
3637 				reg_mask &= ~(1u << i);
3638 				continue;
3639 			}
3640 			if (!reg->precise)
3641 				new_marks = true;
3642 			reg->precise = true;
3643 		}
3644 
3645 		bitmap_from_u64(mask, stack_mask);
3646 		for_each_set_bit(i, mask, 64) {
3647 			if (i >= func->allocated_stack / BPF_REG_SIZE) {
3648 				/* the sequence of instructions:
3649 				 * 2: (bf) r3 = r10
3650 				 * 3: (7b) *(u64 *)(r3 -8) = r0
3651 				 * 4: (79) r4 = *(u64 *)(r10 -8)
3652 				 * doesn't contain jmps. It's backtracked
3653 				 * as a single block.
3654 				 * During backtracking insn 3 is not recognized as
3655 				 * stack access, so at the end of backtracking
3656 				 * stack slot fp-8 is still marked in stack_mask.
3657 				 * However the parent state may not have accessed
3658 				 * fp-8 and it's "unallocated" stack space.
3659 				 * In such case fallback to conservative.
3660 				 */
3661 				mark_all_scalars_precise(env, st);
3662 				return 0;
3663 			}
3664 
3665 			if (!is_spilled_reg(&func->stack[i])) {
3666 				stack_mask &= ~(1ull << i);
3667 				continue;
3668 			}
3669 			reg = &func->stack[i].spilled_ptr;
3670 			if (reg->type != SCALAR_VALUE) {
3671 				stack_mask &= ~(1ull << i);
3672 				continue;
3673 			}
3674 			if (!reg->precise)
3675 				new_marks = true;
3676 			reg->precise = true;
3677 		}
3678 		if (env->log.level & BPF_LOG_LEVEL2) {
3679 			verbose(env, "parent %s regs=%x stack=%llx marks:",
3680 				new_marks ? "didn't have" : "already had",
3681 				reg_mask, stack_mask);
3682 			print_verifier_state(env, func, true);
3683 		}
3684 
3685 		if (!reg_mask && !stack_mask)
3686 			break;
3687 		if (!new_marks)
3688 			break;
3689 
3690 		last_idx = st->last_insn_idx;
3691 		first_idx = st->first_insn_idx;
3692 	}
3693 	return 0;
3694 }
3695 
3696 int mark_chain_precision(struct bpf_verifier_env *env, int regno)
3697 {
3698 	return __mark_chain_precision(env, env->cur_state->curframe, regno, -1);
3699 }
3700 
3701 static int mark_chain_precision_frame(struct bpf_verifier_env *env, int frame, int regno)
3702 {
3703 	return __mark_chain_precision(env, frame, regno, -1);
3704 }
3705 
3706 static int mark_chain_precision_stack_frame(struct bpf_verifier_env *env, int frame, int spi)
3707 {
3708 	return __mark_chain_precision(env, frame, -1, spi);
3709 }
3710 
3711 static bool is_spillable_regtype(enum bpf_reg_type type)
3712 {
3713 	switch (base_type(type)) {
3714 	case PTR_TO_MAP_VALUE:
3715 	case PTR_TO_STACK:
3716 	case PTR_TO_CTX:
3717 	case PTR_TO_PACKET:
3718 	case PTR_TO_PACKET_META:
3719 	case PTR_TO_PACKET_END:
3720 	case PTR_TO_FLOW_KEYS:
3721 	case CONST_PTR_TO_MAP:
3722 	case PTR_TO_SOCKET:
3723 	case PTR_TO_SOCK_COMMON:
3724 	case PTR_TO_TCP_SOCK:
3725 	case PTR_TO_XDP_SOCK:
3726 	case PTR_TO_BTF_ID:
3727 	case PTR_TO_BUF:
3728 	case PTR_TO_MEM:
3729 	case PTR_TO_FUNC:
3730 	case PTR_TO_MAP_KEY:
3731 		return true;
3732 	default:
3733 		return false;
3734 	}
3735 }
3736 
3737 /* Does this register contain a constant zero? */
3738 static bool register_is_null(struct bpf_reg_state *reg)
3739 {
3740 	return reg->type == SCALAR_VALUE && tnum_equals_const(reg->var_off, 0);
3741 }
3742 
3743 static bool register_is_const(struct bpf_reg_state *reg)
3744 {
3745 	return reg->type == SCALAR_VALUE && tnum_is_const(reg->var_off);
3746 }
3747 
3748 static bool __is_scalar_unbounded(struct bpf_reg_state *reg)
3749 {
3750 	return tnum_is_unknown(reg->var_off) &&
3751 	       reg->smin_value == S64_MIN && reg->smax_value == S64_MAX &&
3752 	       reg->umin_value == 0 && reg->umax_value == U64_MAX &&
3753 	       reg->s32_min_value == S32_MIN && reg->s32_max_value == S32_MAX &&
3754 	       reg->u32_min_value == 0 && reg->u32_max_value == U32_MAX;
3755 }
3756 
3757 static bool register_is_bounded(struct bpf_reg_state *reg)
3758 {
3759 	return reg->type == SCALAR_VALUE && !__is_scalar_unbounded(reg);
3760 }
3761 
3762 static bool __is_pointer_value(bool allow_ptr_leaks,
3763 			       const struct bpf_reg_state *reg)
3764 {
3765 	if (allow_ptr_leaks)
3766 		return false;
3767 
3768 	return reg->type != SCALAR_VALUE;
3769 }
3770 
3771 /* Copy src state preserving dst->parent and dst->live fields */
3772 static void copy_register_state(struct bpf_reg_state *dst, const struct bpf_reg_state *src)
3773 {
3774 	struct bpf_reg_state *parent = dst->parent;
3775 	enum bpf_reg_liveness live = dst->live;
3776 
3777 	*dst = *src;
3778 	dst->parent = parent;
3779 	dst->live = live;
3780 }
3781 
3782 static void save_register_state(struct bpf_func_state *state,
3783 				int spi, struct bpf_reg_state *reg,
3784 				int size)
3785 {
3786 	int i;
3787 
3788 	copy_register_state(&state->stack[spi].spilled_ptr, reg);
3789 	if (size == BPF_REG_SIZE)
3790 		state->stack[spi].spilled_ptr.live |= REG_LIVE_WRITTEN;
3791 
3792 	for (i = BPF_REG_SIZE; i > BPF_REG_SIZE - size; i--)
3793 		state->stack[spi].slot_type[i - 1] = STACK_SPILL;
3794 
3795 	/* size < 8 bytes spill */
3796 	for (; i; i--)
3797 		scrub_spilled_slot(&state->stack[spi].slot_type[i - 1]);
3798 }
3799 
3800 static bool is_bpf_st_mem(struct bpf_insn *insn)
3801 {
3802 	return BPF_CLASS(insn->code) == BPF_ST && BPF_MODE(insn->code) == BPF_MEM;
3803 }
3804 
3805 /* check_stack_{read,write}_fixed_off functions track spill/fill of registers,
3806  * stack boundary and alignment are checked in check_mem_access()
3807  */
3808 static int check_stack_write_fixed_off(struct bpf_verifier_env *env,
3809 				       /* stack frame we're writing to */
3810 				       struct bpf_func_state *state,
3811 				       int off, int size, int value_regno,
3812 				       int insn_idx)
3813 {
3814 	struct bpf_func_state *cur; /* state of the current function */
3815 	int i, slot = -off - 1, spi = slot / BPF_REG_SIZE, err;
3816 	struct bpf_insn *insn = &env->prog->insnsi[insn_idx];
3817 	struct bpf_reg_state *reg = NULL;
3818 	u32 dst_reg = insn->dst_reg;
3819 
3820 	err = grow_stack_state(state, round_up(slot + 1, BPF_REG_SIZE));
3821 	if (err)
3822 		return err;
3823 	/* caller checked that off % size == 0 and -MAX_BPF_STACK <= off < 0,
3824 	 * so it's aligned access and [off, off + size) are within stack limits
3825 	 */
3826 	if (!env->allow_ptr_leaks &&
3827 	    state->stack[spi].slot_type[0] == STACK_SPILL &&
3828 	    size != BPF_REG_SIZE) {
3829 		verbose(env, "attempt to corrupt spilled pointer on stack\n");
3830 		return -EACCES;
3831 	}
3832 
3833 	cur = env->cur_state->frame[env->cur_state->curframe];
3834 	if (value_regno >= 0)
3835 		reg = &cur->regs[value_regno];
3836 	if (!env->bypass_spec_v4) {
3837 		bool sanitize = reg && is_spillable_regtype(reg->type);
3838 
3839 		for (i = 0; i < size; i++) {
3840 			u8 type = state->stack[spi].slot_type[i];
3841 
3842 			if (type != STACK_MISC && type != STACK_ZERO) {
3843 				sanitize = true;
3844 				break;
3845 			}
3846 		}
3847 
3848 		if (sanitize)
3849 			env->insn_aux_data[insn_idx].sanitize_stack_spill = true;
3850 	}
3851 
3852 	err = destroy_if_dynptr_stack_slot(env, state, spi);
3853 	if (err)
3854 		return err;
3855 
3856 	mark_stack_slot_scratched(env, spi);
3857 	if (reg && !(off % BPF_REG_SIZE) && register_is_bounded(reg) &&
3858 	    !register_is_null(reg) && env->bpf_capable) {
3859 		if (dst_reg != BPF_REG_FP) {
3860 			/* The backtracking logic can only recognize explicit
3861 			 * stack slot address like [fp - 8]. Other spill of
3862 			 * scalar via different register has to be conservative.
3863 			 * Backtrack from here and mark all registers as precise
3864 			 * that contributed into 'reg' being a constant.
3865 			 */
3866 			err = mark_chain_precision(env, value_regno);
3867 			if (err)
3868 				return err;
3869 		}
3870 		save_register_state(state, spi, reg, size);
3871 	} else if (!reg && !(off % BPF_REG_SIZE) && is_bpf_st_mem(insn) &&
3872 		   insn->imm != 0 && env->bpf_capable) {
3873 		struct bpf_reg_state fake_reg = {};
3874 
3875 		__mark_reg_known(&fake_reg, (u32)insn->imm);
3876 		fake_reg.type = SCALAR_VALUE;
3877 		save_register_state(state, spi, &fake_reg, size);
3878 	} else if (reg && is_spillable_regtype(reg->type)) {
3879 		/* register containing pointer is being spilled into stack */
3880 		if (size != BPF_REG_SIZE) {
3881 			verbose_linfo(env, insn_idx, "; ");
3882 			verbose(env, "invalid size of register spill\n");
3883 			return -EACCES;
3884 		}
3885 		if (state != cur && reg->type == PTR_TO_STACK) {
3886 			verbose(env, "cannot spill pointers to stack into stack frame of the caller\n");
3887 			return -EINVAL;
3888 		}
3889 		save_register_state(state, spi, reg, size);
3890 	} else {
3891 		u8 type = STACK_MISC;
3892 
3893 		/* regular write of data into stack destroys any spilled ptr */
3894 		state->stack[spi].spilled_ptr.type = NOT_INIT;
3895 		/* Mark slots as STACK_MISC if they belonged to spilled ptr/dynptr/iter. */
3896 		if (is_stack_slot_special(&state->stack[spi]))
3897 			for (i = 0; i < BPF_REG_SIZE; i++)
3898 				scrub_spilled_slot(&state->stack[spi].slot_type[i]);
3899 
3900 		/* only mark the slot as written if all 8 bytes were written
3901 		 * otherwise read propagation may incorrectly stop too soon
3902 		 * when stack slots are partially written.
3903 		 * This heuristic means that read propagation will be
3904 		 * conservative, since it will add reg_live_read marks
3905 		 * to stack slots all the way to first state when programs
3906 		 * writes+reads less than 8 bytes
3907 		 */
3908 		if (size == BPF_REG_SIZE)
3909 			state->stack[spi].spilled_ptr.live |= REG_LIVE_WRITTEN;
3910 
3911 		/* when we zero initialize stack slots mark them as such */
3912 		if ((reg && register_is_null(reg)) ||
3913 		    (!reg && is_bpf_st_mem(insn) && insn->imm == 0)) {
3914 			/* backtracking doesn't work for STACK_ZERO yet. */
3915 			err = mark_chain_precision(env, value_regno);
3916 			if (err)
3917 				return err;
3918 			type = STACK_ZERO;
3919 		}
3920 
3921 		/* Mark slots affected by this stack write. */
3922 		for (i = 0; i < size; i++)
3923 			state->stack[spi].slot_type[(slot - i) % BPF_REG_SIZE] =
3924 				type;
3925 	}
3926 	return 0;
3927 }
3928 
3929 /* Write the stack: 'stack[ptr_regno + off] = value_regno'. 'ptr_regno' is
3930  * known to contain a variable offset.
3931  * This function checks whether the write is permitted and conservatively
3932  * tracks the effects of the write, considering that each stack slot in the
3933  * dynamic range is potentially written to.
3934  *
3935  * 'off' includes 'regno->off'.
3936  * 'value_regno' can be -1, meaning that an unknown value is being written to
3937  * the stack.
3938  *
3939  * Spilled pointers in range are not marked as written because we don't know
3940  * what's going to be actually written. This means that read propagation for
3941  * future reads cannot be terminated by this write.
3942  *
3943  * For privileged programs, uninitialized stack slots are considered
3944  * initialized by this write (even though we don't know exactly what offsets
3945  * are going to be written to). The idea is that we don't want the verifier to
3946  * reject future reads that access slots written to through variable offsets.
3947  */
3948 static int check_stack_write_var_off(struct bpf_verifier_env *env,
3949 				     /* func where register points to */
3950 				     struct bpf_func_state *state,
3951 				     int ptr_regno, int off, int size,
3952 				     int value_regno, int insn_idx)
3953 {
3954 	struct bpf_func_state *cur; /* state of the current function */
3955 	int min_off, max_off;
3956 	int i, err;
3957 	struct bpf_reg_state *ptr_reg = NULL, *value_reg = NULL;
3958 	struct bpf_insn *insn = &env->prog->insnsi[insn_idx];
3959 	bool writing_zero = false;
3960 	/* set if the fact that we're writing a zero is used to let any
3961 	 * stack slots remain STACK_ZERO
3962 	 */
3963 	bool zero_used = false;
3964 
3965 	cur = env->cur_state->frame[env->cur_state->curframe];
3966 	ptr_reg = &cur->regs[ptr_regno];
3967 	min_off = ptr_reg->smin_value + off;
3968 	max_off = ptr_reg->smax_value + off + size;
3969 	if (value_regno >= 0)
3970 		value_reg = &cur->regs[value_regno];
3971 	if ((value_reg && register_is_null(value_reg)) ||
3972 	    (!value_reg && is_bpf_st_mem(insn) && insn->imm == 0))
3973 		writing_zero = true;
3974 
3975 	err = grow_stack_state(state, round_up(-min_off, BPF_REG_SIZE));
3976 	if (err)
3977 		return err;
3978 
3979 	for (i = min_off; i < max_off; i++) {
3980 		int spi;
3981 
3982 		spi = __get_spi(i);
3983 		err = destroy_if_dynptr_stack_slot(env, state, spi);
3984 		if (err)
3985 			return err;
3986 	}
3987 
3988 	/* Variable offset writes destroy any spilled pointers in range. */
3989 	for (i = min_off; i < max_off; i++) {
3990 		u8 new_type, *stype;
3991 		int slot, spi;
3992 
3993 		slot = -i - 1;
3994 		spi = slot / BPF_REG_SIZE;
3995 		stype = &state->stack[spi].slot_type[slot % BPF_REG_SIZE];
3996 		mark_stack_slot_scratched(env, spi);
3997 
3998 		if (!env->allow_ptr_leaks && *stype != STACK_MISC && *stype != STACK_ZERO) {
3999 			/* Reject the write if range we may write to has not
4000 			 * been initialized beforehand. If we didn't reject
4001 			 * here, the ptr status would be erased below (even
4002 			 * though not all slots are actually overwritten),
4003 			 * possibly opening the door to leaks.
4004 			 *
4005 			 * We do however catch STACK_INVALID case below, and
4006 			 * only allow reading possibly uninitialized memory
4007 			 * later for CAP_PERFMON, as the write may not happen to
4008 			 * that slot.
4009 			 */
4010 			verbose(env, "spilled ptr in range of var-offset stack write; insn %d, ptr off: %d",
4011 				insn_idx, i);
4012 			return -EINVAL;
4013 		}
4014 
4015 		/* Erase all spilled pointers. */
4016 		state->stack[spi].spilled_ptr.type = NOT_INIT;
4017 
4018 		/* Update the slot type. */
4019 		new_type = STACK_MISC;
4020 		if (writing_zero && *stype == STACK_ZERO) {
4021 			new_type = STACK_ZERO;
4022 			zero_used = true;
4023 		}
4024 		/* If the slot is STACK_INVALID, we check whether it's OK to
4025 		 * pretend that it will be initialized by this write. The slot
4026 		 * might not actually be written to, and so if we mark it as
4027 		 * initialized future reads might leak uninitialized memory.
4028 		 * For privileged programs, we will accept such reads to slots
4029 		 * that may or may not be written because, if we're reject
4030 		 * them, the error would be too confusing.
4031 		 */
4032 		if (*stype == STACK_INVALID && !env->allow_uninit_stack) {
4033 			verbose(env, "uninit stack in range of var-offset write prohibited for !root; insn %d, off: %d",
4034 					insn_idx, i);
4035 			return -EINVAL;
4036 		}
4037 		*stype = new_type;
4038 	}
4039 	if (zero_used) {
4040 		/* backtracking doesn't work for STACK_ZERO yet. */
4041 		err = mark_chain_precision(env, value_regno);
4042 		if (err)
4043 			return err;
4044 	}
4045 	return 0;
4046 }
4047 
4048 /* When register 'dst_regno' is assigned some values from stack[min_off,
4049  * max_off), we set the register's type according to the types of the
4050  * respective stack slots. If all the stack values are known to be zeros, then
4051  * so is the destination reg. Otherwise, the register is considered to be
4052  * SCALAR. This function does not deal with register filling; the caller must
4053  * ensure that all spilled registers in the stack range have been marked as
4054  * read.
4055  */
4056 static void mark_reg_stack_read(struct bpf_verifier_env *env,
4057 				/* func where src register points to */
4058 				struct bpf_func_state *ptr_state,
4059 				int min_off, int max_off, int dst_regno)
4060 {
4061 	struct bpf_verifier_state *vstate = env->cur_state;
4062 	struct bpf_func_state *state = vstate->frame[vstate->curframe];
4063 	int i, slot, spi;
4064 	u8 *stype;
4065 	int zeros = 0;
4066 
4067 	for (i = min_off; i < max_off; i++) {
4068 		slot = -i - 1;
4069 		spi = slot / BPF_REG_SIZE;
4070 		stype = ptr_state->stack[spi].slot_type;
4071 		if (stype[slot % BPF_REG_SIZE] != STACK_ZERO)
4072 			break;
4073 		zeros++;
4074 	}
4075 	if (zeros == max_off - min_off) {
4076 		/* any access_size read into register is zero extended,
4077 		 * so the whole register == const_zero
4078 		 */
4079 		__mark_reg_const_zero(&state->regs[dst_regno]);
4080 		/* backtracking doesn't support STACK_ZERO yet,
4081 		 * so mark it precise here, so that later
4082 		 * backtracking can stop here.
4083 		 * Backtracking may not need this if this register
4084 		 * doesn't participate in pointer adjustment.
4085 		 * Forward propagation of precise flag is not
4086 		 * necessary either. This mark is only to stop
4087 		 * backtracking. Any register that contributed
4088 		 * to const 0 was marked precise before spill.
4089 		 */
4090 		state->regs[dst_regno].precise = true;
4091 	} else {
4092 		/* have read misc data from the stack */
4093 		mark_reg_unknown(env, state->regs, dst_regno);
4094 	}
4095 	state->regs[dst_regno].live |= REG_LIVE_WRITTEN;
4096 }
4097 
4098 /* Read the stack at 'off' and put the results into the register indicated by
4099  * 'dst_regno'. It handles reg filling if the addressed stack slot is a
4100  * spilled reg.
4101  *
4102  * 'dst_regno' can be -1, meaning that the read value is not going to a
4103  * register.
4104  *
4105  * The access is assumed to be within the current stack bounds.
4106  */
4107 static int check_stack_read_fixed_off(struct bpf_verifier_env *env,
4108 				      /* func where src register points to */
4109 				      struct bpf_func_state *reg_state,
4110 				      int off, int size, int dst_regno)
4111 {
4112 	struct bpf_verifier_state *vstate = env->cur_state;
4113 	struct bpf_func_state *state = vstate->frame[vstate->curframe];
4114 	int i, slot = -off - 1, spi = slot / BPF_REG_SIZE;
4115 	struct bpf_reg_state *reg;
4116 	u8 *stype, type;
4117 
4118 	stype = reg_state->stack[spi].slot_type;
4119 	reg = &reg_state->stack[spi].spilled_ptr;
4120 
4121 	if (is_spilled_reg(&reg_state->stack[spi])) {
4122 		u8 spill_size = 1;
4123 
4124 		for (i = BPF_REG_SIZE - 1; i > 0 && stype[i - 1] == STACK_SPILL; i--)
4125 			spill_size++;
4126 
4127 		if (size != BPF_REG_SIZE || spill_size != BPF_REG_SIZE) {
4128 			if (reg->type != SCALAR_VALUE) {
4129 				verbose_linfo(env, env->insn_idx, "; ");
4130 				verbose(env, "invalid size of register fill\n");
4131 				return -EACCES;
4132 			}
4133 
4134 			mark_reg_read(env, reg, reg->parent, REG_LIVE_READ64);
4135 			if (dst_regno < 0)
4136 				return 0;
4137 
4138 			if (!(off % BPF_REG_SIZE) && size == spill_size) {
4139 				/* The earlier check_reg_arg() has decided the
4140 				 * subreg_def for this insn.  Save it first.
4141 				 */
4142 				s32 subreg_def = state->regs[dst_regno].subreg_def;
4143 
4144 				copy_register_state(&state->regs[dst_regno], reg);
4145 				state->regs[dst_regno].subreg_def = subreg_def;
4146 			} else {
4147 				for (i = 0; i < size; i++) {
4148 					type = stype[(slot - i) % BPF_REG_SIZE];
4149 					if (type == STACK_SPILL)
4150 						continue;
4151 					if (type == STACK_MISC)
4152 						continue;
4153 					if (type == STACK_INVALID && env->allow_uninit_stack)
4154 						continue;
4155 					verbose(env, "invalid read from stack off %d+%d size %d\n",
4156 						off, i, size);
4157 					return -EACCES;
4158 				}
4159 				mark_reg_unknown(env, state->regs, dst_regno);
4160 			}
4161 			state->regs[dst_regno].live |= REG_LIVE_WRITTEN;
4162 			return 0;
4163 		}
4164 
4165 		if (dst_regno >= 0) {
4166 			/* restore register state from stack */
4167 			copy_register_state(&state->regs[dst_regno], reg);
4168 			/* mark reg as written since spilled pointer state likely
4169 			 * has its liveness marks cleared by is_state_visited()
4170 			 * which resets stack/reg liveness for state transitions
4171 			 */
4172 			state->regs[dst_regno].live |= REG_LIVE_WRITTEN;
4173 		} else if (__is_pointer_value(env->allow_ptr_leaks, reg)) {
4174 			/* If dst_regno==-1, the caller is asking us whether
4175 			 * it is acceptable to use this value as a SCALAR_VALUE
4176 			 * (e.g. for XADD).
4177 			 * We must not allow unprivileged callers to do that
4178 			 * with spilled pointers.
4179 			 */
4180 			verbose(env, "leaking pointer from stack off %d\n",
4181 				off);
4182 			return -EACCES;
4183 		}
4184 		mark_reg_read(env, reg, reg->parent, REG_LIVE_READ64);
4185 	} else {
4186 		for (i = 0; i < size; i++) {
4187 			type = stype[(slot - i) % BPF_REG_SIZE];
4188 			if (type == STACK_MISC)
4189 				continue;
4190 			if (type == STACK_ZERO)
4191 				continue;
4192 			if (type == STACK_INVALID && env->allow_uninit_stack)
4193 				continue;
4194 			verbose(env, "invalid read from stack off %d+%d size %d\n",
4195 				off, i, size);
4196 			return -EACCES;
4197 		}
4198 		mark_reg_read(env, reg, reg->parent, REG_LIVE_READ64);
4199 		if (dst_regno >= 0)
4200 			mark_reg_stack_read(env, reg_state, off, off + size, dst_regno);
4201 	}
4202 	return 0;
4203 }
4204 
4205 enum bpf_access_src {
4206 	ACCESS_DIRECT = 1,  /* the access is performed by an instruction */
4207 	ACCESS_HELPER = 2,  /* the access is performed by a helper */
4208 };
4209 
4210 static int check_stack_range_initialized(struct bpf_verifier_env *env,
4211 					 int regno, int off, int access_size,
4212 					 bool zero_size_allowed,
4213 					 enum bpf_access_src type,
4214 					 struct bpf_call_arg_meta *meta);
4215 
4216 static struct bpf_reg_state *reg_state(struct bpf_verifier_env *env, int regno)
4217 {
4218 	return cur_regs(env) + regno;
4219 }
4220 
4221 /* Read the stack at 'ptr_regno + off' and put the result into the register
4222  * 'dst_regno'.
4223  * 'off' includes the pointer register's fixed offset(i.e. 'ptr_regno.off'),
4224  * but not its variable offset.
4225  * 'size' is assumed to be <= reg size and the access is assumed to be aligned.
4226  *
4227  * As opposed to check_stack_read_fixed_off, this function doesn't deal with
4228  * filling registers (i.e. reads of spilled register cannot be detected when
4229  * the offset is not fixed). We conservatively mark 'dst_regno' as containing
4230  * SCALAR_VALUE. That's why we assert that the 'ptr_regno' has a variable
4231  * offset; for a fixed offset check_stack_read_fixed_off should be used
4232  * instead.
4233  */
4234 static int check_stack_read_var_off(struct bpf_verifier_env *env,
4235 				    int ptr_regno, int off, int size, int dst_regno)
4236 {
4237 	/* The state of the source register. */
4238 	struct bpf_reg_state *reg = reg_state(env, ptr_regno);
4239 	struct bpf_func_state *ptr_state = func(env, reg);
4240 	int err;
4241 	int min_off, max_off;
4242 
4243 	/* Note that we pass a NULL meta, so raw access will not be permitted.
4244 	 */
4245 	err = check_stack_range_initialized(env, ptr_regno, off, size,
4246 					    false, ACCESS_DIRECT, NULL);
4247 	if (err)
4248 		return err;
4249 
4250 	min_off = reg->smin_value + off;
4251 	max_off = reg->smax_value + off;
4252 	mark_reg_stack_read(env, ptr_state, min_off, max_off + size, dst_regno);
4253 	return 0;
4254 }
4255 
4256 /* check_stack_read dispatches to check_stack_read_fixed_off or
4257  * check_stack_read_var_off.
4258  *
4259  * The caller must ensure that the offset falls within the allocated stack
4260  * bounds.
4261  *
4262  * 'dst_regno' is a register which will receive the value from the stack. It
4263  * can be -1, meaning that the read value is not going to a register.
4264  */
4265 static int check_stack_read(struct bpf_verifier_env *env,
4266 			    int ptr_regno, int off, int size,
4267 			    int dst_regno)
4268 {
4269 	struct bpf_reg_state *reg = reg_state(env, ptr_regno);
4270 	struct bpf_func_state *state = func(env, reg);
4271 	int err;
4272 	/* Some accesses are only permitted with a static offset. */
4273 	bool var_off = !tnum_is_const(reg->var_off);
4274 
4275 	/* The offset is required to be static when reads don't go to a
4276 	 * register, in order to not leak pointers (see
4277 	 * check_stack_read_fixed_off).
4278 	 */
4279 	if (dst_regno < 0 && var_off) {
4280 		char tn_buf[48];
4281 
4282 		tnum_strn(tn_buf, sizeof(tn_buf), reg->var_off);
4283 		verbose(env, "variable offset stack pointer cannot be passed into helper function; var_off=%s off=%d size=%d\n",
4284 			tn_buf, off, size);
4285 		return -EACCES;
4286 	}
4287 	/* Variable offset is prohibited for unprivileged mode for simplicity
4288 	 * since it requires corresponding support in Spectre masking for stack
4289 	 * ALU. See also retrieve_ptr_limit(). The check in
4290 	 * check_stack_access_for_ptr_arithmetic() called by
4291 	 * adjust_ptr_min_max_vals() prevents users from creating stack pointers
4292 	 * with variable offsets, therefore no check is required here. Further,
4293 	 * just checking it here would be insufficient as speculative stack
4294 	 * writes could still lead to unsafe speculative behaviour.
4295 	 */
4296 	if (!var_off) {
4297 		off += reg->var_off.value;
4298 		err = check_stack_read_fixed_off(env, state, off, size,
4299 						 dst_regno);
4300 	} else {
4301 		/* Variable offset stack reads need more conservative handling
4302 		 * than fixed offset ones. Note that dst_regno >= 0 on this
4303 		 * branch.
4304 		 */
4305 		err = check_stack_read_var_off(env, ptr_regno, off, size,
4306 					       dst_regno);
4307 	}
4308 	return err;
4309 }
4310 
4311 
4312 /* check_stack_write dispatches to check_stack_write_fixed_off or
4313  * check_stack_write_var_off.
4314  *
4315  * 'ptr_regno' is the register used as a pointer into the stack.
4316  * 'off' includes 'ptr_regno->off', but not its variable offset (if any).
4317  * 'value_regno' is the register whose value we're writing to the stack. It can
4318  * be -1, meaning that we're not writing from a register.
4319  *
4320  * The caller must ensure that the offset falls within the maximum stack size.
4321  */
4322 static int check_stack_write(struct bpf_verifier_env *env,
4323 			     int ptr_regno, int off, int size,
4324 			     int value_regno, int insn_idx)
4325 {
4326 	struct bpf_reg_state *reg = reg_state(env, ptr_regno);
4327 	struct bpf_func_state *state = func(env, reg);
4328 	int err;
4329 
4330 	if (tnum_is_const(reg->var_off)) {
4331 		off += reg->var_off.value;
4332 		err = check_stack_write_fixed_off(env, state, off, size,
4333 						  value_regno, insn_idx);
4334 	} else {
4335 		/* Variable offset stack reads need more conservative handling
4336 		 * than fixed offset ones.
4337 		 */
4338 		err = check_stack_write_var_off(env, state,
4339 						ptr_regno, off, size,
4340 						value_regno, insn_idx);
4341 	}
4342 	return err;
4343 }
4344 
4345 static int check_map_access_type(struct bpf_verifier_env *env, u32 regno,
4346 				 int off, int size, enum bpf_access_type type)
4347 {
4348 	struct bpf_reg_state *regs = cur_regs(env);
4349 	struct bpf_map *map = regs[regno].map_ptr;
4350 	u32 cap = bpf_map_flags_to_cap(map);
4351 
4352 	if (type == BPF_WRITE && !(cap & BPF_MAP_CAN_WRITE)) {
4353 		verbose(env, "write into map forbidden, value_size=%d off=%d size=%d\n",
4354 			map->value_size, off, size);
4355 		return -EACCES;
4356 	}
4357 
4358 	if (type == BPF_READ && !(cap & BPF_MAP_CAN_READ)) {
4359 		verbose(env, "read from map forbidden, value_size=%d off=%d size=%d\n",
4360 			map->value_size, off, size);
4361 		return -EACCES;
4362 	}
4363 
4364 	return 0;
4365 }
4366 
4367 /* check read/write into memory region (e.g., map value, ringbuf sample, etc) */
4368 static int __check_mem_access(struct bpf_verifier_env *env, int regno,
4369 			      int off, int size, u32 mem_size,
4370 			      bool zero_size_allowed)
4371 {
4372 	bool size_ok = size > 0 || (size == 0 && zero_size_allowed);
4373 	struct bpf_reg_state *reg;
4374 
4375 	if (off >= 0 && size_ok && (u64)off + size <= mem_size)
4376 		return 0;
4377 
4378 	reg = &cur_regs(env)[regno];
4379 	switch (reg->type) {
4380 	case PTR_TO_MAP_KEY:
4381 		verbose(env, "invalid access to map key, key_size=%d off=%d size=%d\n",
4382 			mem_size, off, size);
4383 		break;
4384 	case PTR_TO_MAP_VALUE:
4385 		verbose(env, "invalid access to map value, value_size=%d off=%d size=%d\n",
4386 			mem_size, off, size);
4387 		break;
4388 	case PTR_TO_PACKET:
4389 	case PTR_TO_PACKET_META:
4390 	case PTR_TO_PACKET_END:
4391 		verbose(env, "invalid access to packet, off=%d size=%d, R%d(id=%d,off=%d,r=%d)\n",
4392 			off, size, regno, reg->id, off, mem_size);
4393 		break;
4394 	case PTR_TO_MEM:
4395 	default:
4396 		verbose(env, "invalid access to memory, mem_size=%u off=%d size=%d\n",
4397 			mem_size, off, size);
4398 	}
4399 
4400 	return -EACCES;
4401 }
4402 
4403 /* check read/write into a memory region with possible variable offset */
4404 static int check_mem_region_access(struct bpf_verifier_env *env, u32 regno,
4405 				   int off, int size, u32 mem_size,
4406 				   bool zero_size_allowed)
4407 {
4408 	struct bpf_verifier_state *vstate = env->cur_state;
4409 	struct bpf_func_state *state = vstate->frame[vstate->curframe];
4410 	struct bpf_reg_state *reg = &state->regs[regno];
4411 	int err;
4412 
4413 	/* We may have adjusted the register pointing to memory region, so we
4414 	 * need to try adding each of min_value and max_value to off
4415 	 * to make sure our theoretical access will be safe.
4416 	 *
4417 	 * The minimum value is only important with signed
4418 	 * comparisons where we can't assume the floor of a
4419 	 * value is 0.  If we are using signed variables for our
4420 	 * index'es we need to make sure that whatever we use
4421 	 * will have a set floor within our range.
4422 	 */
4423 	if (reg->smin_value < 0 &&
4424 	    (reg->smin_value == S64_MIN ||
4425 	     (off + reg->smin_value != (s64)(s32)(off + reg->smin_value)) ||
4426 	      reg->smin_value + off < 0)) {
4427 		verbose(env, "R%d min value is negative, either use unsigned index or do a if (index >=0) check.\n",
4428 			regno);
4429 		return -EACCES;
4430 	}
4431 	err = __check_mem_access(env, regno, reg->smin_value + off, size,
4432 				 mem_size, zero_size_allowed);
4433 	if (err) {
4434 		verbose(env, "R%d min value is outside of the allowed memory range\n",
4435 			regno);
4436 		return err;
4437 	}
4438 
4439 	/* If we haven't set a max value then we need to bail since we can't be
4440 	 * sure we won't do bad things.
4441 	 * If reg->umax_value + off could overflow, treat that as unbounded too.
4442 	 */
4443 	if (reg->umax_value >= BPF_MAX_VAR_OFF) {
4444 		verbose(env, "R%d unbounded memory access, make sure to bounds check any such access\n",
4445 			regno);
4446 		return -EACCES;
4447 	}
4448 	err = __check_mem_access(env, regno, reg->umax_value + off, size,
4449 				 mem_size, zero_size_allowed);
4450 	if (err) {
4451 		verbose(env, "R%d max value is outside of the allowed memory range\n",
4452 			regno);
4453 		return err;
4454 	}
4455 
4456 	return 0;
4457 }
4458 
4459 static int __check_ptr_off_reg(struct bpf_verifier_env *env,
4460 			       const struct bpf_reg_state *reg, int regno,
4461 			       bool fixed_off_ok)
4462 {
4463 	/* Access to this pointer-typed register or passing it to a helper
4464 	 * is only allowed in its original, unmodified form.
4465 	 */
4466 
4467 	if (reg->off < 0) {
4468 		verbose(env, "negative offset %s ptr R%d off=%d disallowed\n",
4469 			reg_type_str(env, reg->type), regno, reg->off);
4470 		return -EACCES;
4471 	}
4472 
4473 	if (!fixed_off_ok && reg->off) {
4474 		verbose(env, "dereference of modified %s ptr R%d off=%d disallowed\n",
4475 			reg_type_str(env, reg->type), regno, reg->off);
4476 		return -EACCES;
4477 	}
4478 
4479 	if (!tnum_is_const(reg->var_off) || reg->var_off.value) {
4480 		char tn_buf[48];
4481 
4482 		tnum_strn(tn_buf, sizeof(tn_buf), reg->var_off);
4483 		verbose(env, "variable %s access var_off=%s disallowed\n",
4484 			reg_type_str(env, reg->type), tn_buf);
4485 		return -EACCES;
4486 	}
4487 
4488 	return 0;
4489 }
4490 
4491 int check_ptr_off_reg(struct bpf_verifier_env *env,
4492 		      const struct bpf_reg_state *reg, int regno)
4493 {
4494 	return __check_ptr_off_reg(env, reg, regno, false);
4495 }
4496 
4497 static int map_kptr_match_type(struct bpf_verifier_env *env,
4498 			       struct btf_field *kptr_field,
4499 			       struct bpf_reg_state *reg, u32 regno)
4500 {
4501 	const char *targ_name = btf_type_name(kptr_field->kptr.btf, kptr_field->kptr.btf_id);
4502 	int perm_flags = PTR_MAYBE_NULL | PTR_TRUSTED | MEM_RCU;
4503 	const char *reg_name = "";
4504 
4505 	/* Only unreferenced case accepts untrusted pointers */
4506 	if (kptr_field->type == BPF_KPTR_UNREF)
4507 		perm_flags |= PTR_UNTRUSTED;
4508 
4509 	if (base_type(reg->type) != PTR_TO_BTF_ID || (type_flag(reg->type) & ~perm_flags))
4510 		goto bad_type;
4511 
4512 	if (!btf_is_kernel(reg->btf)) {
4513 		verbose(env, "R%d must point to kernel BTF\n", regno);
4514 		return -EINVAL;
4515 	}
4516 	/* We need to verify reg->type and reg->btf, before accessing reg->btf */
4517 	reg_name = btf_type_name(reg->btf, reg->btf_id);
4518 
4519 	/* For ref_ptr case, release function check should ensure we get one
4520 	 * referenced PTR_TO_BTF_ID, and that its fixed offset is 0. For the
4521 	 * normal store of unreferenced kptr, we must ensure var_off is zero.
4522 	 * Since ref_ptr cannot be accessed directly by BPF insns, checks for
4523 	 * reg->off and reg->ref_obj_id are not needed here.
4524 	 */
4525 	if (__check_ptr_off_reg(env, reg, regno, true))
4526 		return -EACCES;
4527 
4528 	/* A full type match is needed, as BTF can be vmlinux or module BTF, and
4529 	 * we also need to take into account the reg->off.
4530 	 *
4531 	 * We want to support cases like:
4532 	 *
4533 	 * struct foo {
4534 	 *         struct bar br;
4535 	 *         struct baz bz;
4536 	 * };
4537 	 *
4538 	 * struct foo *v;
4539 	 * v = func();	      // PTR_TO_BTF_ID
4540 	 * val->foo = v;      // reg->off is zero, btf and btf_id match type
4541 	 * val->bar = &v->br; // reg->off is still zero, but we need to retry with
4542 	 *                    // first member type of struct after comparison fails
4543 	 * val->baz = &v->bz; // reg->off is non-zero, so struct needs to be walked
4544 	 *                    // to match type
4545 	 *
4546 	 * In the kptr_ref case, check_func_arg_reg_off already ensures reg->off
4547 	 * is zero. We must also ensure that btf_struct_ids_match does not walk
4548 	 * the struct to match type against first member of struct, i.e. reject
4549 	 * second case from above. Hence, when type is BPF_KPTR_REF, we set
4550 	 * strict mode to true for type match.
4551 	 */
4552 	if (!btf_struct_ids_match(&env->log, reg->btf, reg->btf_id, reg->off,
4553 				  kptr_field->kptr.btf, kptr_field->kptr.btf_id,
4554 				  kptr_field->type == BPF_KPTR_REF))
4555 		goto bad_type;
4556 	return 0;
4557 bad_type:
4558 	verbose(env, "invalid kptr access, R%d type=%s%s ", regno,
4559 		reg_type_str(env, reg->type), reg_name);
4560 	verbose(env, "expected=%s%s", reg_type_str(env, PTR_TO_BTF_ID), targ_name);
4561 	if (kptr_field->type == BPF_KPTR_UNREF)
4562 		verbose(env, " or %s%s\n", reg_type_str(env, PTR_TO_BTF_ID | PTR_UNTRUSTED),
4563 			targ_name);
4564 	else
4565 		verbose(env, "\n");
4566 	return -EINVAL;
4567 }
4568 
4569 /* The non-sleepable programs and sleepable programs with explicit bpf_rcu_read_lock()
4570  * can dereference RCU protected pointers and result is PTR_TRUSTED.
4571  */
4572 static bool in_rcu_cs(struct bpf_verifier_env *env)
4573 {
4574 	return env->cur_state->active_rcu_lock || !env->prog->aux->sleepable;
4575 }
4576 
4577 /* Once GCC supports btf_type_tag the following mechanism will be replaced with tag check */
4578 BTF_SET_START(rcu_protected_types)
4579 BTF_ID(struct, prog_test_ref_kfunc)
4580 BTF_ID(struct, cgroup)
4581 BTF_ID(struct, bpf_cpumask)
4582 BTF_ID(struct, task_struct)
4583 BTF_SET_END(rcu_protected_types)
4584 
4585 static bool rcu_protected_object(const struct btf *btf, u32 btf_id)
4586 {
4587 	if (!btf_is_kernel(btf))
4588 		return false;
4589 	return btf_id_set_contains(&rcu_protected_types, btf_id);
4590 }
4591 
4592 static bool rcu_safe_kptr(const struct btf_field *field)
4593 {
4594 	const struct btf_field_kptr *kptr = &field->kptr;
4595 
4596 	return field->type == BPF_KPTR_REF && rcu_protected_object(kptr->btf, kptr->btf_id);
4597 }
4598 
4599 static int check_map_kptr_access(struct bpf_verifier_env *env, u32 regno,
4600 				 int value_regno, int insn_idx,
4601 				 struct btf_field *kptr_field)
4602 {
4603 	struct bpf_insn *insn = &env->prog->insnsi[insn_idx];
4604 	int class = BPF_CLASS(insn->code);
4605 	struct bpf_reg_state *val_reg;
4606 
4607 	/* Things we already checked for in check_map_access and caller:
4608 	 *  - Reject cases where variable offset may touch kptr
4609 	 *  - size of access (must be BPF_DW)
4610 	 *  - tnum_is_const(reg->var_off)
4611 	 *  - kptr_field->offset == off + reg->var_off.value
4612 	 */
4613 	/* Only BPF_[LDX,STX,ST] | BPF_MEM | BPF_DW is supported */
4614 	if (BPF_MODE(insn->code) != BPF_MEM) {
4615 		verbose(env, "kptr in map can only be accessed using BPF_MEM instruction mode\n");
4616 		return -EACCES;
4617 	}
4618 
4619 	/* We only allow loading referenced kptr, since it will be marked as
4620 	 * untrusted, similar to unreferenced kptr.
4621 	 */
4622 	if (class != BPF_LDX && kptr_field->type == BPF_KPTR_REF) {
4623 		verbose(env, "store to referenced kptr disallowed\n");
4624 		return -EACCES;
4625 	}
4626 
4627 	if (class == BPF_LDX) {
4628 		val_reg = reg_state(env, value_regno);
4629 		/* We can simply mark the value_regno receiving the pointer
4630 		 * value from map as PTR_TO_BTF_ID, with the correct type.
4631 		 */
4632 		mark_btf_ld_reg(env, cur_regs(env), value_regno, PTR_TO_BTF_ID, kptr_field->kptr.btf,
4633 				kptr_field->kptr.btf_id,
4634 				rcu_safe_kptr(kptr_field) && in_rcu_cs(env) ?
4635 				PTR_MAYBE_NULL | MEM_RCU :
4636 				PTR_MAYBE_NULL | PTR_UNTRUSTED);
4637 		/* For mark_ptr_or_null_reg */
4638 		val_reg->id = ++env->id_gen;
4639 	} else if (class == BPF_STX) {
4640 		val_reg = reg_state(env, value_regno);
4641 		if (!register_is_null(val_reg) &&
4642 		    map_kptr_match_type(env, kptr_field, val_reg, value_regno))
4643 			return -EACCES;
4644 	} else if (class == BPF_ST) {
4645 		if (insn->imm) {
4646 			verbose(env, "BPF_ST imm must be 0 when storing to kptr at off=%u\n",
4647 				kptr_field->offset);
4648 			return -EACCES;
4649 		}
4650 	} else {
4651 		verbose(env, "kptr in map can only be accessed using BPF_LDX/BPF_STX/BPF_ST\n");
4652 		return -EACCES;
4653 	}
4654 	return 0;
4655 }
4656 
4657 /* check read/write into a map element with possible variable offset */
4658 static int check_map_access(struct bpf_verifier_env *env, u32 regno,
4659 			    int off, int size, bool zero_size_allowed,
4660 			    enum bpf_access_src src)
4661 {
4662 	struct bpf_verifier_state *vstate = env->cur_state;
4663 	struct bpf_func_state *state = vstate->frame[vstate->curframe];
4664 	struct bpf_reg_state *reg = &state->regs[regno];
4665 	struct bpf_map *map = reg->map_ptr;
4666 	struct btf_record *rec;
4667 	int err, i;
4668 
4669 	err = check_mem_region_access(env, regno, off, size, map->value_size,
4670 				      zero_size_allowed);
4671 	if (err)
4672 		return err;
4673 
4674 	if (IS_ERR_OR_NULL(map->record))
4675 		return 0;
4676 	rec = map->record;
4677 	for (i = 0; i < rec->cnt; i++) {
4678 		struct btf_field *field = &rec->fields[i];
4679 		u32 p = field->offset;
4680 
4681 		/* If any part of a field  can be touched by load/store, reject
4682 		 * this program. To check that [x1, x2) overlaps with [y1, y2),
4683 		 * it is sufficient to check x1 < y2 && y1 < x2.
4684 		 */
4685 		if (reg->smin_value + off < p + btf_field_type_size(field->type) &&
4686 		    p < reg->umax_value + off + size) {
4687 			switch (field->type) {
4688 			case BPF_KPTR_UNREF:
4689 			case BPF_KPTR_REF:
4690 				if (src != ACCESS_DIRECT) {
4691 					verbose(env, "kptr cannot be accessed indirectly by helper\n");
4692 					return -EACCES;
4693 				}
4694 				if (!tnum_is_const(reg->var_off)) {
4695 					verbose(env, "kptr access cannot have variable offset\n");
4696 					return -EACCES;
4697 				}
4698 				if (p != off + reg->var_off.value) {
4699 					verbose(env, "kptr access misaligned expected=%u off=%llu\n",
4700 						p, off + reg->var_off.value);
4701 					return -EACCES;
4702 				}
4703 				if (size != bpf_size_to_bytes(BPF_DW)) {
4704 					verbose(env, "kptr access size must be BPF_DW\n");
4705 					return -EACCES;
4706 				}
4707 				break;
4708 			default:
4709 				verbose(env, "%s cannot be accessed directly by load/store\n",
4710 					btf_field_type_name(field->type));
4711 				return -EACCES;
4712 			}
4713 		}
4714 	}
4715 	return 0;
4716 }
4717 
4718 #define MAX_PACKET_OFF 0xffff
4719 
4720 static bool may_access_direct_pkt_data(struct bpf_verifier_env *env,
4721 				       const struct bpf_call_arg_meta *meta,
4722 				       enum bpf_access_type t)
4723 {
4724 	enum bpf_prog_type prog_type = resolve_prog_type(env->prog);
4725 
4726 	switch (prog_type) {
4727 	/* Program types only with direct read access go here! */
4728 	case BPF_PROG_TYPE_LWT_IN:
4729 	case BPF_PROG_TYPE_LWT_OUT:
4730 	case BPF_PROG_TYPE_LWT_SEG6LOCAL:
4731 	case BPF_PROG_TYPE_SK_REUSEPORT:
4732 	case BPF_PROG_TYPE_FLOW_DISSECTOR:
4733 	case BPF_PROG_TYPE_CGROUP_SKB:
4734 		if (t == BPF_WRITE)
4735 			return false;
4736 		fallthrough;
4737 
4738 	/* Program types with direct read + write access go here! */
4739 	case BPF_PROG_TYPE_SCHED_CLS:
4740 	case BPF_PROG_TYPE_SCHED_ACT:
4741 	case BPF_PROG_TYPE_XDP:
4742 	case BPF_PROG_TYPE_LWT_XMIT:
4743 	case BPF_PROG_TYPE_SK_SKB:
4744 	case BPF_PROG_TYPE_SK_MSG:
4745 		if (meta)
4746 			return meta->pkt_access;
4747 
4748 		env->seen_direct_write = true;
4749 		return true;
4750 
4751 	case BPF_PROG_TYPE_CGROUP_SOCKOPT:
4752 		if (t == BPF_WRITE)
4753 			env->seen_direct_write = true;
4754 
4755 		return true;
4756 
4757 	default:
4758 		return false;
4759 	}
4760 }
4761 
4762 static int check_packet_access(struct bpf_verifier_env *env, u32 regno, int off,
4763 			       int size, bool zero_size_allowed)
4764 {
4765 	struct bpf_reg_state *regs = cur_regs(env);
4766 	struct bpf_reg_state *reg = &regs[regno];
4767 	int err;
4768 
4769 	/* We may have added a variable offset to the packet pointer; but any
4770 	 * reg->range we have comes after that.  We are only checking the fixed
4771 	 * offset.
4772 	 */
4773 
4774 	/* We don't allow negative numbers, because we aren't tracking enough
4775 	 * detail to prove they're safe.
4776 	 */
4777 	if (reg->smin_value < 0) {
4778 		verbose(env, "R%d min value is negative, either use unsigned index or do a if (index >=0) check.\n",
4779 			regno);
4780 		return -EACCES;
4781 	}
4782 
4783 	err = reg->range < 0 ? -EINVAL :
4784 	      __check_mem_access(env, regno, off, size, reg->range,
4785 				 zero_size_allowed);
4786 	if (err) {
4787 		verbose(env, "R%d offset is outside of the packet\n", regno);
4788 		return err;
4789 	}
4790 
4791 	/* __check_mem_access has made sure "off + size - 1" is within u16.
4792 	 * reg->umax_value can't be bigger than MAX_PACKET_OFF which is 0xffff,
4793 	 * otherwise find_good_pkt_pointers would have refused to set range info
4794 	 * that __check_mem_access would have rejected this pkt access.
4795 	 * Therefore, "off + reg->umax_value + size - 1" won't overflow u32.
4796 	 */
4797 	env->prog->aux->max_pkt_offset =
4798 		max_t(u32, env->prog->aux->max_pkt_offset,
4799 		      off + reg->umax_value + size - 1);
4800 
4801 	return err;
4802 }
4803 
4804 /* check access to 'struct bpf_context' fields.  Supports fixed offsets only */
4805 static int check_ctx_access(struct bpf_verifier_env *env, int insn_idx, int off, int size,
4806 			    enum bpf_access_type t, enum bpf_reg_type *reg_type,
4807 			    struct btf **btf, u32 *btf_id)
4808 {
4809 	struct bpf_insn_access_aux info = {
4810 		.reg_type = *reg_type,
4811 		.log = &env->log,
4812 	};
4813 
4814 	if (env->ops->is_valid_access &&
4815 	    env->ops->is_valid_access(off, size, t, env->prog, &info)) {
4816 		/* A non zero info.ctx_field_size indicates that this field is a
4817 		 * candidate for later verifier transformation to load the whole
4818 		 * field and then apply a mask when accessed with a narrower
4819 		 * access than actual ctx access size. A zero info.ctx_field_size
4820 		 * will only allow for whole field access and rejects any other
4821 		 * type of narrower access.
4822 		 */
4823 		*reg_type = info.reg_type;
4824 
4825 		if (base_type(*reg_type) == PTR_TO_BTF_ID) {
4826 			*btf = info.btf;
4827 			*btf_id = info.btf_id;
4828 		} else {
4829 			env->insn_aux_data[insn_idx].ctx_field_size = info.ctx_field_size;
4830 		}
4831 		/* remember the offset of last byte accessed in ctx */
4832 		if (env->prog->aux->max_ctx_offset < off + size)
4833 			env->prog->aux->max_ctx_offset = off + size;
4834 		return 0;
4835 	}
4836 
4837 	verbose(env, "invalid bpf_context access off=%d size=%d\n", off, size);
4838 	return -EACCES;
4839 }
4840 
4841 static int check_flow_keys_access(struct bpf_verifier_env *env, int off,
4842 				  int size)
4843 {
4844 	if (size < 0 || off < 0 ||
4845 	    (u64)off + size > sizeof(struct bpf_flow_keys)) {
4846 		verbose(env, "invalid access to flow keys off=%d size=%d\n",
4847 			off, size);
4848 		return -EACCES;
4849 	}
4850 	return 0;
4851 }
4852 
4853 static int check_sock_access(struct bpf_verifier_env *env, int insn_idx,
4854 			     u32 regno, int off, int size,
4855 			     enum bpf_access_type t)
4856 {
4857 	struct bpf_reg_state *regs = cur_regs(env);
4858 	struct bpf_reg_state *reg = &regs[regno];
4859 	struct bpf_insn_access_aux info = {};
4860 	bool valid;
4861 
4862 	if (reg->smin_value < 0) {
4863 		verbose(env, "R%d min value is negative, either use unsigned index or do a if (index >=0) check.\n",
4864 			regno);
4865 		return -EACCES;
4866 	}
4867 
4868 	switch (reg->type) {
4869 	case PTR_TO_SOCK_COMMON:
4870 		valid = bpf_sock_common_is_valid_access(off, size, t, &info);
4871 		break;
4872 	case PTR_TO_SOCKET:
4873 		valid = bpf_sock_is_valid_access(off, size, t, &info);
4874 		break;
4875 	case PTR_TO_TCP_SOCK:
4876 		valid = bpf_tcp_sock_is_valid_access(off, size, t, &info);
4877 		break;
4878 	case PTR_TO_XDP_SOCK:
4879 		valid = bpf_xdp_sock_is_valid_access(off, size, t, &info);
4880 		break;
4881 	default:
4882 		valid = false;
4883 	}
4884 
4885 
4886 	if (valid) {
4887 		env->insn_aux_data[insn_idx].ctx_field_size =
4888 			info.ctx_field_size;
4889 		return 0;
4890 	}
4891 
4892 	verbose(env, "R%d invalid %s access off=%d size=%d\n",
4893 		regno, reg_type_str(env, reg->type), off, size);
4894 
4895 	return -EACCES;
4896 }
4897 
4898 static bool is_pointer_value(struct bpf_verifier_env *env, int regno)
4899 {
4900 	return __is_pointer_value(env->allow_ptr_leaks, reg_state(env, regno));
4901 }
4902 
4903 static bool is_ctx_reg(struct bpf_verifier_env *env, int regno)
4904 {
4905 	const struct bpf_reg_state *reg = reg_state(env, regno);
4906 
4907 	return reg->type == PTR_TO_CTX;
4908 }
4909 
4910 static bool is_sk_reg(struct bpf_verifier_env *env, int regno)
4911 {
4912 	const struct bpf_reg_state *reg = reg_state(env, regno);
4913 
4914 	return type_is_sk_pointer(reg->type);
4915 }
4916 
4917 static bool is_pkt_reg(struct bpf_verifier_env *env, int regno)
4918 {
4919 	const struct bpf_reg_state *reg = reg_state(env, regno);
4920 
4921 	return type_is_pkt_pointer(reg->type);
4922 }
4923 
4924 static bool is_flow_key_reg(struct bpf_verifier_env *env, int regno)
4925 {
4926 	const struct bpf_reg_state *reg = reg_state(env, regno);
4927 
4928 	/* Separate to is_ctx_reg() since we still want to allow BPF_ST here. */
4929 	return reg->type == PTR_TO_FLOW_KEYS;
4930 }
4931 
4932 static bool is_trusted_reg(const struct bpf_reg_state *reg)
4933 {
4934 	/* A referenced register is always trusted. */
4935 	if (reg->ref_obj_id)
4936 		return true;
4937 
4938 	/* If a register is not referenced, it is trusted if it has the
4939 	 * MEM_ALLOC or PTR_TRUSTED type modifiers, and no others. Some of the
4940 	 * other type modifiers may be safe, but we elect to take an opt-in
4941 	 * approach here as some (e.g. PTR_UNTRUSTED and PTR_MAYBE_NULL) are
4942 	 * not.
4943 	 *
4944 	 * Eventually, we should make PTR_TRUSTED the single source of truth
4945 	 * for whether a register is trusted.
4946 	 */
4947 	return type_flag(reg->type) & BPF_REG_TRUSTED_MODIFIERS &&
4948 	       !bpf_type_has_unsafe_modifiers(reg->type);
4949 }
4950 
4951 static bool is_rcu_reg(const struct bpf_reg_state *reg)
4952 {
4953 	return reg->type & MEM_RCU;
4954 }
4955 
4956 static void clear_trusted_flags(enum bpf_type_flag *flag)
4957 {
4958 	*flag &= ~(BPF_REG_TRUSTED_MODIFIERS | MEM_RCU);
4959 }
4960 
4961 static int check_pkt_ptr_alignment(struct bpf_verifier_env *env,
4962 				   const struct bpf_reg_state *reg,
4963 				   int off, int size, bool strict)
4964 {
4965 	struct tnum reg_off;
4966 	int ip_align;
4967 
4968 	/* Byte size accesses are always allowed. */
4969 	if (!strict || size == 1)
4970 		return 0;
4971 
4972 	/* For platforms that do not have a Kconfig enabling
4973 	 * CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS the value of
4974 	 * NET_IP_ALIGN is universally set to '2'.  And on platforms
4975 	 * that do set CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS, we get
4976 	 * to this code only in strict mode where we want to emulate
4977 	 * the NET_IP_ALIGN==2 checking.  Therefore use an
4978 	 * unconditional IP align value of '2'.
4979 	 */
4980 	ip_align = 2;
4981 
4982 	reg_off = tnum_add(reg->var_off, tnum_const(ip_align + reg->off + off));
4983 	if (!tnum_is_aligned(reg_off, size)) {
4984 		char tn_buf[48];
4985 
4986 		tnum_strn(tn_buf, sizeof(tn_buf), reg->var_off);
4987 		verbose(env,
4988 			"misaligned packet access off %d+%s+%d+%d size %d\n",
4989 			ip_align, tn_buf, reg->off, off, size);
4990 		return -EACCES;
4991 	}
4992 
4993 	return 0;
4994 }
4995 
4996 static int check_generic_ptr_alignment(struct bpf_verifier_env *env,
4997 				       const struct bpf_reg_state *reg,
4998 				       const char *pointer_desc,
4999 				       int off, int size, bool strict)
5000 {
5001 	struct tnum reg_off;
5002 
5003 	/* Byte size accesses are always allowed. */
5004 	if (!strict || size == 1)
5005 		return 0;
5006 
5007 	reg_off = tnum_add(reg->var_off, tnum_const(reg->off + off));
5008 	if (!tnum_is_aligned(reg_off, size)) {
5009 		char tn_buf[48];
5010 
5011 		tnum_strn(tn_buf, sizeof(tn_buf), reg->var_off);
5012 		verbose(env, "misaligned %saccess off %s+%d+%d size %d\n",
5013 			pointer_desc, tn_buf, reg->off, off, size);
5014 		return -EACCES;
5015 	}
5016 
5017 	return 0;
5018 }
5019 
5020 static int check_ptr_alignment(struct bpf_verifier_env *env,
5021 			       const struct bpf_reg_state *reg, int off,
5022 			       int size, bool strict_alignment_once)
5023 {
5024 	bool strict = env->strict_alignment || strict_alignment_once;
5025 	const char *pointer_desc = "";
5026 
5027 	switch (reg->type) {
5028 	case PTR_TO_PACKET:
5029 	case PTR_TO_PACKET_META:
5030 		/* Special case, because of NET_IP_ALIGN. Given metadata sits
5031 		 * right in front, treat it the very same way.
5032 		 */
5033 		return check_pkt_ptr_alignment(env, reg, off, size, strict);
5034 	case PTR_TO_FLOW_KEYS:
5035 		pointer_desc = "flow keys ";
5036 		break;
5037 	case PTR_TO_MAP_KEY:
5038 		pointer_desc = "key ";
5039 		break;
5040 	case PTR_TO_MAP_VALUE:
5041 		pointer_desc = "value ";
5042 		break;
5043 	case PTR_TO_CTX:
5044 		pointer_desc = "context ";
5045 		break;
5046 	case PTR_TO_STACK:
5047 		pointer_desc = "stack ";
5048 		/* The stack spill tracking logic in check_stack_write_fixed_off()
5049 		 * and check_stack_read_fixed_off() relies on stack accesses being
5050 		 * aligned.
5051 		 */
5052 		strict = true;
5053 		break;
5054 	case PTR_TO_SOCKET:
5055 		pointer_desc = "sock ";
5056 		break;
5057 	case PTR_TO_SOCK_COMMON:
5058 		pointer_desc = "sock_common ";
5059 		break;
5060 	case PTR_TO_TCP_SOCK:
5061 		pointer_desc = "tcp_sock ";
5062 		break;
5063 	case PTR_TO_XDP_SOCK:
5064 		pointer_desc = "xdp_sock ";
5065 		break;
5066 	default:
5067 		break;
5068 	}
5069 	return check_generic_ptr_alignment(env, reg, pointer_desc, off, size,
5070 					   strict);
5071 }
5072 
5073 static int update_stack_depth(struct bpf_verifier_env *env,
5074 			      const struct bpf_func_state *func,
5075 			      int off)
5076 {
5077 	u16 stack = env->subprog_info[func->subprogno].stack_depth;
5078 
5079 	if (stack >= -off)
5080 		return 0;
5081 
5082 	/* update known max for given subprogram */
5083 	env->subprog_info[func->subprogno].stack_depth = -off;
5084 	return 0;
5085 }
5086 
5087 /* starting from main bpf function walk all instructions of the function
5088  * and recursively walk all callees that given function can call.
5089  * Ignore jump and exit insns.
5090  * Since recursion is prevented by check_cfg() this algorithm
5091  * only needs a local stack of MAX_CALL_FRAMES to remember callsites
5092  */
5093 static int check_max_stack_depth(struct bpf_verifier_env *env)
5094 {
5095 	int depth = 0, frame = 0, idx = 0, i = 0, subprog_end;
5096 	struct bpf_subprog_info *subprog = env->subprog_info;
5097 	struct bpf_insn *insn = env->prog->insnsi;
5098 	bool tail_call_reachable = false;
5099 	int ret_insn[MAX_CALL_FRAMES];
5100 	int ret_prog[MAX_CALL_FRAMES];
5101 	int j;
5102 
5103 process_func:
5104 	/* protect against potential stack overflow that might happen when
5105 	 * bpf2bpf calls get combined with tailcalls. Limit the caller's stack
5106 	 * depth for such case down to 256 so that the worst case scenario
5107 	 * would result in 8k stack size (32 which is tailcall limit * 256 =
5108 	 * 8k).
5109 	 *
5110 	 * To get the idea what might happen, see an example:
5111 	 * func1 -> sub rsp, 128
5112 	 *  subfunc1 -> sub rsp, 256
5113 	 *  tailcall1 -> add rsp, 256
5114 	 *   func2 -> sub rsp, 192 (total stack size = 128 + 192 = 320)
5115 	 *   subfunc2 -> sub rsp, 64
5116 	 *   subfunc22 -> sub rsp, 128
5117 	 *   tailcall2 -> add rsp, 128
5118 	 *    func3 -> sub rsp, 32 (total stack size 128 + 192 + 64 + 32 = 416)
5119 	 *
5120 	 * tailcall will unwind the current stack frame but it will not get rid
5121 	 * of caller's stack as shown on the example above.
5122 	 */
5123 	if (idx && subprog[idx].has_tail_call && depth >= 256) {
5124 		verbose(env,
5125 			"tail_calls are not allowed when call stack of previous frames is %d bytes. Too large\n",
5126 			depth);
5127 		return -EACCES;
5128 	}
5129 	/* round up to 32-bytes, since this is granularity
5130 	 * of interpreter stack size
5131 	 */
5132 	depth += round_up(max_t(u32, subprog[idx].stack_depth, 1), 32);
5133 	if (depth > MAX_BPF_STACK) {
5134 		verbose(env, "combined stack size of %d calls is %d. Too large\n",
5135 			frame + 1, depth);
5136 		return -EACCES;
5137 	}
5138 continue_func:
5139 	subprog_end = subprog[idx + 1].start;
5140 	for (; i < subprog_end; i++) {
5141 		int next_insn;
5142 
5143 		if (!bpf_pseudo_call(insn + i) && !bpf_pseudo_func(insn + i))
5144 			continue;
5145 		/* remember insn and function to return to */
5146 		ret_insn[frame] = i + 1;
5147 		ret_prog[frame] = idx;
5148 
5149 		/* find the callee */
5150 		next_insn = i + insn[i].imm + 1;
5151 		idx = find_subprog(env, next_insn);
5152 		if (idx < 0) {
5153 			WARN_ONCE(1, "verifier bug. No program starts at insn %d\n",
5154 				  next_insn);
5155 			return -EFAULT;
5156 		}
5157 		if (subprog[idx].is_async_cb) {
5158 			if (subprog[idx].has_tail_call) {
5159 				verbose(env, "verifier bug. subprog has tail_call and async cb\n");
5160 				return -EFAULT;
5161 			}
5162 			 /* async callbacks don't increase bpf prog stack size */
5163 			continue;
5164 		}
5165 		i = next_insn;
5166 
5167 		if (subprog[idx].has_tail_call)
5168 			tail_call_reachable = true;
5169 
5170 		frame++;
5171 		if (frame >= MAX_CALL_FRAMES) {
5172 			verbose(env, "the call stack of %d frames is too deep !\n",
5173 				frame);
5174 			return -E2BIG;
5175 		}
5176 		goto process_func;
5177 	}
5178 	/* if tail call got detected across bpf2bpf calls then mark each of the
5179 	 * currently present subprog frames as tail call reachable subprogs;
5180 	 * this info will be utilized by JIT so that we will be preserving the
5181 	 * tail call counter throughout bpf2bpf calls combined with tailcalls
5182 	 */
5183 	if (tail_call_reachable)
5184 		for (j = 0; j < frame; j++)
5185 			subprog[ret_prog[j]].tail_call_reachable = true;
5186 	if (subprog[0].tail_call_reachable)
5187 		env->prog->aux->tail_call_reachable = true;
5188 
5189 	/* end of for() loop means the last insn of the 'subprog'
5190 	 * was reached. Doesn't matter whether it was JA or EXIT
5191 	 */
5192 	if (frame == 0)
5193 		return 0;
5194 	depth -= round_up(max_t(u32, subprog[idx].stack_depth, 1), 32);
5195 	frame--;
5196 	i = ret_insn[frame];
5197 	idx = ret_prog[frame];
5198 	goto continue_func;
5199 }
5200 
5201 #ifndef CONFIG_BPF_JIT_ALWAYS_ON
5202 static int get_callee_stack_depth(struct bpf_verifier_env *env,
5203 				  const struct bpf_insn *insn, int idx)
5204 {
5205 	int start = idx + insn->imm + 1, subprog;
5206 
5207 	subprog = find_subprog(env, start);
5208 	if (subprog < 0) {
5209 		WARN_ONCE(1, "verifier bug. No program starts at insn %d\n",
5210 			  start);
5211 		return -EFAULT;
5212 	}
5213 	return env->subprog_info[subprog].stack_depth;
5214 }
5215 #endif
5216 
5217 static int __check_buffer_access(struct bpf_verifier_env *env,
5218 				 const char *buf_info,
5219 				 const struct bpf_reg_state *reg,
5220 				 int regno, int off, int size)
5221 {
5222 	if (off < 0) {
5223 		verbose(env,
5224 			"R%d invalid %s buffer access: off=%d, size=%d\n",
5225 			regno, buf_info, off, size);
5226 		return -EACCES;
5227 	}
5228 	if (!tnum_is_const(reg->var_off) || reg->var_off.value) {
5229 		char tn_buf[48];
5230 
5231 		tnum_strn(tn_buf, sizeof(tn_buf), reg->var_off);
5232 		verbose(env,
5233 			"R%d invalid variable buffer offset: off=%d, var_off=%s\n",
5234 			regno, off, tn_buf);
5235 		return -EACCES;
5236 	}
5237 
5238 	return 0;
5239 }
5240 
5241 static int check_tp_buffer_access(struct bpf_verifier_env *env,
5242 				  const struct bpf_reg_state *reg,
5243 				  int regno, int off, int size)
5244 {
5245 	int err;
5246 
5247 	err = __check_buffer_access(env, "tracepoint", reg, regno, off, size);
5248 	if (err)
5249 		return err;
5250 
5251 	if (off + size > env->prog->aux->max_tp_access)
5252 		env->prog->aux->max_tp_access = off + size;
5253 
5254 	return 0;
5255 }
5256 
5257 static int check_buffer_access(struct bpf_verifier_env *env,
5258 			       const struct bpf_reg_state *reg,
5259 			       int regno, int off, int size,
5260 			       bool zero_size_allowed,
5261 			       u32 *max_access)
5262 {
5263 	const char *buf_info = type_is_rdonly_mem(reg->type) ? "rdonly" : "rdwr";
5264 	int err;
5265 
5266 	err = __check_buffer_access(env, buf_info, reg, regno, off, size);
5267 	if (err)
5268 		return err;
5269 
5270 	if (off + size > *max_access)
5271 		*max_access = off + size;
5272 
5273 	return 0;
5274 }
5275 
5276 /* BPF architecture zero extends alu32 ops into 64-bit registesr */
5277 static void zext_32_to_64(struct bpf_reg_state *reg)
5278 {
5279 	reg->var_off = tnum_subreg(reg->var_off);
5280 	__reg_assign_32_into_64(reg);
5281 }
5282 
5283 /* truncate register to smaller size (in bytes)
5284  * must be called with size < BPF_REG_SIZE
5285  */
5286 static void coerce_reg_to_size(struct bpf_reg_state *reg, int size)
5287 {
5288 	u64 mask;
5289 
5290 	/* clear high bits in bit representation */
5291 	reg->var_off = tnum_cast(reg->var_off, size);
5292 
5293 	/* fix arithmetic bounds */
5294 	mask = ((u64)1 << (size * 8)) - 1;
5295 	if ((reg->umin_value & ~mask) == (reg->umax_value & ~mask)) {
5296 		reg->umin_value &= mask;
5297 		reg->umax_value &= mask;
5298 	} else {
5299 		reg->umin_value = 0;
5300 		reg->umax_value = mask;
5301 	}
5302 	reg->smin_value = reg->umin_value;
5303 	reg->smax_value = reg->umax_value;
5304 
5305 	/* If size is smaller than 32bit register the 32bit register
5306 	 * values are also truncated so we push 64-bit bounds into
5307 	 * 32-bit bounds. Above were truncated < 32-bits already.
5308 	 */
5309 	if (size >= 4)
5310 		return;
5311 	__reg_combine_64_into_32(reg);
5312 }
5313 
5314 static bool bpf_map_is_rdonly(const struct bpf_map *map)
5315 {
5316 	/* A map is considered read-only if the following condition are true:
5317 	 *
5318 	 * 1) BPF program side cannot change any of the map content. The
5319 	 *    BPF_F_RDONLY_PROG flag is throughout the lifetime of a map
5320 	 *    and was set at map creation time.
5321 	 * 2) The map value(s) have been initialized from user space by a
5322 	 *    loader and then "frozen", such that no new map update/delete
5323 	 *    operations from syscall side are possible for the rest of
5324 	 *    the map's lifetime from that point onwards.
5325 	 * 3) Any parallel/pending map update/delete operations from syscall
5326 	 *    side have been completed. Only after that point, it's safe to
5327 	 *    assume that map value(s) are immutable.
5328 	 */
5329 	return (map->map_flags & BPF_F_RDONLY_PROG) &&
5330 	       READ_ONCE(map->frozen) &&
5331 	       !bpf_map_write_active(map);
5332 }
5333 
5334 static int bpf_map_direct_read(struct bpf_map *map, int off, int size, u64 *val)
5335 {
5336 	void *ptr;
5337 	u64 addr;
5338 	int err;
5339 
5340 	err = map->ops->map_direct_value_addr(map, &addr, off);
5341 	if (err)
5342 		return err;
5343 	ptr = (void *)(long)addr + off;
5344 
5345 	switch (size) {
5346 	case sizeof(u8):
5347 		*val = (u64)*(u8 *)ptr;
5348 		break;
5349 	case sizeof(u16):
5350 		*val = (u64)*(u16 *)ptr;
5351 		break;
5352 	case sizeof(u32):
5353 		*val = (u64)*(u32 *)ptr;
5354 		break;
5355 	case sizeof(u64):
5356 		*val = *(u64 *)ptr;
5357 		break;
5358 	default:
5359 		return -EINVAL;
5360 	}
5361 	return 0;
5362 }
5363 
5364 #define BTF_TYPE_SAFE_RCU(__type)  __PASTE(__type, __safe_rcu)
5365 #define BTF_TYPE_SAFE_RCU_OR_NULL(__type)  __PASTE(__type, __safe_rcu_or_null)
5366 #define BTF_TYPE_SAFE_TRUSTED(__type)  __PASTE(__type, __safe_trusted)
5367 
5368 /*
5369  * Allow list few fields as RCU trusted or full trusted.
5370  * This logic doesn't allow mix tagging and will be removed once GCC supports
5371  * btf_type_tag.
5372  */
5373 
5374 /* RCU trusted: these fields are trusted in RCU CS and never NULL */
5375 BTF_TYPE_SAFE_RCU(struct task_struct) {
5376 	const cpumask_t *cpus_ptr;
5377 	struct css_set __rcu *cgroups;
5378 	struct task_struct __rcu *real_parent;
5379 	struct task_struct *group_leader;
5380 };
5381 
5382 BTF_TYPE_SAFE_RCU(struct cgroup) {
5383 	/* cgrp->kn is always accessible as documented in kernel/cgroup/cgroup.c */
5384 	struct kernfs_node *kn;
5385 };
5386 
5387 BTF_TYPE_SAFE_RCU(struct css_set) {
5388 	struct cgroup *dfl_cgrp;
5389 };
5390 
5391 /* RCU trusted: these fields are trusted in RCU CS and can be NULL */
5392 BTF_TYPE_SAFE_RCU_OR_NULL(struct mm_struct) {
5393 	struct file __rcu *exe_file;
5394 };
5395 
5396 /* skb->sk, req->sk are not RCU protected, but we mark them as such
5397  * because bpf prog accessible sockets are SOCK_RCU_FREE.
5398  */
5399 BTF_TYPE_SAFE_RCU_OR_NULL(struct sk_buff) {
5400 	struct sock *sk;
5401 };
5402 
5403 BTF_TYPE_SAFE_RCU_OR_NULL(struct request_sock) {
5404 	struct sock *sk;
5405 };
5406 
5407 /* full trusted: these fields are trusted even outside of RCU CS and never NULL */
5408 BTF_TYPE_SAFE_TRUSTED(struct bpf_iter_meta) {
5409 	struct seq_file *seq;
5410 };
5411 
5412 BTF_TYPE_SAFE_TRUSTED(struct bpf_iter__task) {
5413 	struct bpf_iter_meta *meta;
5414 	struct task_struct *task;
5415 };
5416 
5417 BTF_TYPE_SAFE_TRUSTED(struct linux_binprm) {
5418 	struct file *file;
5419 };
5420 
5421 BTF_TYPE_SAFE_TRUSTED(struct file) {
5422 	struct inode *f_inode;
5423 };
5424 
5425 BTF_TYPE_SAFE_TRUSTED(struct dentry) {
5426 	/* no negative dentry-s in places where bpf can see it */
5427 	struct inode *d_inode;
5428 };
5429 
5430 BTF_TYPE_SAFE_TRUSTED(struct socket) {
5431 	struct sock *sk;
5432 };
5433 
5434 static bool type_is_rcu(struct bpf_verifier_env *env,
5435 			struct bpf_reg_state *reg,
5436 			const char *field_name, u32 btf_id)
5437 {
5438 	BTF_TYPE_EMIT(BTF_TYPE_SAFE_RCU(struct task_struct));
5439 	BTF_TYPE_EMIT(BTF_TYPE_SAFE_RCU(struct cgroup));
5440 	BTF_TYPE_EMIT(BTF_TYPE_SAFE_RCU(struct css_set));
5441 
5442 	return btf_nested_type_is_trusted(&env->log, reg, field_name, btf_id, "__safe_rcu");
5443 }
5444 
5445 static bool type_is_rcu_or_null(struct bpf_verifier_env *env,
5446 				struct bpf_reg_state *reg,
5447 				const char *field_name, u32 btf_id)
5448 {
5449 	BTF_TYPE_EMIT(BTF_TYPE_SAFE_RCU_OR_NULL(struct mm_struct));
5450 	BTF_TYPE_EMIT(BTF_TYPE_SAFE_RCU_OR_NULL(struct sk_buff));
5451 	BTF_TYPE_EMIT(BTF_TYPE_SAFE_RCU_OR_NULL(struct request_sock));
5452 
5453 	return btf_nested_type_is_trusted(&env->log, reg, field_name, btf_id, "__safe_rcu_or_null");
5454 }
5455 
5456 static bool type_is_trusted(struct bpf_verifier_env *env,
5457 			    struct bpf_reg_state *reg,
5458 			    const char *field_name, u32 btf_id)
5459 {
5460 	BTF_TYPE_EMIT(BTF_TYPE_SAFE_TRUSTED(struct bpf_iter_meta));
5461 	BTF_TYPE_EMIT(BTF_TYPE_SAFE_TRUSTED(struct bpf_iter__task));
5462 	BTF_TYPE_EMIT(BTF_TYPE_SAFE_TRUSTED(struct linux_binprm));
5463 	BTF_TYPE_EMIT(BTF_TYPE_SAFE_TRUSTED(struct file));
5464 	BTF_TYPE_EMIT(BTF_TYPE_SAFE_TRUSTED(struct dentry));
5465 	BTF_TYPE_EMIT(BTF_TYPE_SAFE_TRUSTED(struct socket));
5466 
5467 	return btf_nested_type_is_trusted(&env->log, reg, field_name, btf_id, "__safe_trusted");
5468 }
5469 
5470 static int check_ptr_to_btf_access(struct bpf_verifier_env *env,
5471 				   struct bpf_reg_state *regs,
5472 				   int regno, int off, int size,
5473 				   enum bpf_access_type atype,
5474 				   int value_regno)
5475 {
5476 	struct bpf_reg_state *reg = regs + regno;
5477 	const struct btf_type *t = btf_type_by_id(reg->btf, reg->btf_id);
5478 	const char *tname = btf_name_by_offset(reg->btf, t->name_off);
5479 	const char *field_name = NULL;
5480 	enum bpf_type_flag flag = 0;
5481 	u32 btf_id = 0;
5482 	int ret;
5483 
5484 	if (!env->allow_ptr_leaks) {
5485 		verbose(env,
5486 			"'struct %s' access is allowed only to CAP_PERFMON and CAP_SYS_ADMIN\n",
5487 			tname);
5488 		return -EPERM;
5489 	}
5490 	if (!env->prog->gpl_compatible && btf_is_kernel(reg->btf)) {
5491 		verbose(env,
5492 			"Cannot access kernel 'struct %s' from non-GPL compatible program\n",
5493 			tname);
5494 		return -EINVAL;
5495 	}
5496 	if (off < 0) {
5497 		verbose(env,
5498 			"R%d is ptr_%s invalid negative access: off=%d\n",
5499 			regno, tname, off);
5500 		return -EACCES;
5501 	}
5502 	if (!tnum_is_const(reg->var_off) || reg->var_off.value) {
5503 		char tn_buf[48];
5504 
5505 		tnum_strn(tn_buf, sizeof(tn_buf), reg->var_off);
5506 		verbose(env,
5507 			"R%d is ptr_%s invalid variable offset: off=%d, var_off=%s\n",
5508 			regno, tname, off, tn_buf);
5509 		return -EACCES;
5510 	}
5511 
5512 	if (reg->type & MEM_USER) {
5513 		verbose(env,
5514 			"R%d is ptr_%s access user memory: off=%d\n",
5515 			regno, tname, off);
5516 		return -EACCES;
5517 	}
5518 
5519 	if (reg->type & MEM_PERCPU) {
5520 		verbose(env,
5521 			"R%d is ptr_%s access percpu memory: off=%d\n",
5522 			regno, tname, off);
5523 		return -EACCES;
5524 	}
5525 
5526 	if (env->ops->btf_struct_access && !type_is_alloc(reg->type) && atype == BPF_WRITE) {
5527 		if (!btf_is_kernel(reg->btf)) {
5528 			verbose(env, "verifier internal error: reg->btf must be kernel btf\n");
5529 			return -EFAULT;
5530 		}
5531 		ret = env->ops->btf_struct_access(&env->log, reg, off, size);
5532 	} else {
5533 		/* Writes are permitted with default btf_struct_access for
5534 		 * program allocated objects (which always have ref_obj_id > 0),
5535 		 * but not for untrusted PTR_TO_BTF_ID | MEM_ALLOC.
5536 		 */
5537 		if (atype != BPF_READ && reg->type != (PTR_TO_BTF_ID | MEM_ALLOC)) {
5538 			verbose(env, "only read is supported\n");
5539 			return -EACCES;
5540 		}
5541 
5542 		if (type_is_alloc(reg->type) && !type_is_non_owning_ref(reg->type) &&
5543 		    !reg->ref_obj_id) {
5544 			verbose(env, "verifier internal error: ref_obj_id for allocated object must be non-zero\n");
5545 			return -EFAULT;
5546 		}
5547 
5548 		ret = btf_struct_access(&env->log, reg, off, size, atype, &btf_id, &flag, &field_name);
5549 	}
5550 
5551 	if (ret < 0)
5552 		return ret;
5553 
5554 	if (ret != PTR_TO_BTF_ID) {
5555 		/* just mark; */
5556 
5557 	} else if (type_flag(reg->type) & PTR_UNTRUSTED) {
5558 		/* If this is an untrusted pointer, all pointers formed by walking it
5559 		 * also inherit the untrusted flag.
5560 		 */
5561 		flag = PTR_UNTRUSTED;
5562 
5563 	} else if (is_trusted_reg(reg) || is_rcu_reg(reg)) {
5564 		/* By default any pointer obtained from walking a trusted pointer is no
5565 		 * longer trusted, unless the field being accessed has explicitly been
5566 		 * marked as inheriting its parent's state of trust (either full or RCU).
5567 		 * For example:
5568 		 * 'cgroups' pointer is untrusted if task->cgroups dereference
5569 		 * happened in a sleepable program outside of bpf_rcu_read_lock()
5570 		 * section. In a non-sleepable program it's trusted while in RCU CS (aka MEM_RCU).
5571 		 * Note bpf_rcu_read_unlock() converts MEM_RCU pointers to PTR_UNTRUSTED.
5572 		 *
5573 		 * A regular RCU-protected pointer with __rcu tag can also be deemed
5574 		 * trusted if we are in an RCU CS. Such pointer can be NULL.
5575 		 */
5576 		if (type_is_trusted(env, reg, field_name, btf_id)) {
5577 			flag |= PTR_TRUSTED;
5578 		} else if (in_rcu_cs(env) && !type_may_be_null(reg->type)) {
5579 			if (type_is_rcu(env, reg, field_name, btf_id)) {
5580 				/* ignore __rcu tag and mark it MEM_RCU */
5581 				flag |= MEM_RCU;
5582 			} else if (flag & MEM_RCU ||
5583 				   type_is_rcu_or_null(env, reg, field_name, btf_id)) {
5584 				/* __rcu tagged pointers can be NULL */
5585 				flag |= MEM_RCU | PTR_MAYBE_NULL;
5586 			} else if (flag & (MEM_PERCPU | MEM_USER)) {
5587 				/* keep as-is */
5588 			} else {
5589 				/* walking unknown pointers yields old deprecated PTR_TO_BTF_ID */
5590 				clear_trusted_flags(&flag);
5591 			}
5592 		} else {
5593 			/*
5594 			 * If not in RCU CS or MEM_RCU pointer can be NULL then
5595 			 * aggressively mark as untrusted otherwise such
5596 			 * pointers will be plain PTR_TO_BTF_ID without flags
5597 			 * and will be allowed to be passed into helpers for
5598 			 * compat reasons.
5599 			 */
5600 			flag = PTR_UNTRUSTED;
5601 		}
5602 	} else {
5603 		/* Old compat. Deprecated */
5604 		clear_trusted_flags(&flag);
5605 	}
5606 
5607 	if (atype == BPF_READ && value_regno >= 0)
5608 		mark_btf_ld_reg(env, regs, value_regno, ret, reg->btf, btf_id, flag);
5609 
5610 	return 0;
5611 }
5612 
5613 static int check_ptr_to_map_access(struct bpf_verifier_env *env,
5614 				   struct bpf_reg_state *regs,
5615 				   int regno, int off, int size,
5616 				   enum bpf_access_type atype,
5617 				   int value_regno)
5618 {
5619 	struct bpf_reg_state *reg = regs + regno;
5620 	struct bpf_map *map = reg->map_ptr;
5621 	struct bpf_reg_state map_reg;
5622 	enum bpf_type_flag flag = 0;
5623 	const struct btf_type *t;
5624 	const char *tname;
5625 	u32 btf_id;
5626 	int ret;
5627 
5628 	if (!btf_vmlinux) {
5629 		verbose(env, "map_ptr access not supported without CONFIG_DEBUG_INFO_BTF\n");
5630 		return -ENOTSUPP;
5631 	}
5632 
5633 	if (!map->ops->map_btf_id || !*map->ops->map_btf_id) {
5634 		verbose(env, "map_ptr access not supported for map type %d\n",
5635 			map->map_type);
5636 		return -ENOTSUPP;
5637 	}
5638 
5639 	t = btf_type_by_id(btf_vmlinux, *map->ops->map_btf_id);
5640 	tname = btf_name_by_offset(btf_vmlinux, t->name_off);
5641 
5642 	if (!env->allow_ptr_leaks) {
5643 		verbose(env,
5644 			"'struct %s' access is allowed only to CAP_PERFMON and CAP_SYS_ADMIN\n",
5645 			tname);
5646 		return -EPERM;
5647 	}
5648 
5649 	if (off < 0) {
5650 		verbose(env, "R%d is %s invalid negative access: off=%d\n",
5651 			regno, tname, off);
5652 		return -EACCES;
5653 	}
5654 
5655 	if (atype != BPF_READ) {
5656 		verbose(env, "only read from %s is supported\n", tname);
5657 		return -EACCES;
5658 	}
5659 
5660 	/* Simulate access to a PTR_TO_BTF_ID */
5661 	memset(&map_reg, 0, sizeof(map_reg));
5662 	mark_btf_ld_reg(env, &map_reg, 0, PTR_TO_BTF_ID, btf_vmlinux, *map->ops->map_btf_id, 0);
5663 	ret = btf_struct_access(&env->log, &map_reg, off, size, atype, &btf_id, &flag, NULL);
5664 	if (ret < 0)
5665 		return ret;
5666 
5667 	if (value_regno >= 0)
5668 		mark_btf_ld_reg(env, regs, value_regno, ret, btf_vmlinux, btf_id, flag);
5669 
5670 	return 0;
5671 }
5672 
5673 /* Check that the stack access at the given offset is within bounds. The
5674  * maximum valid offset is -1.
5675  *
5676  * The minimum valid offset is -MAX_BPF_STACK for writes, and
5677  * -state->allocated_stack for reads.
5678  */
5679 static int check_stack_slot_within_bounds(int off,
5680 					  struct bpf_func_state *state,
5681 					  enum bpf_access_type t)
5682 {
5683 	int min_valid_off;
5684 
5685 	if (t == BPF_WRITE)
5686 		min_valid_off = -MAX_BPF_STACK;
5687 	else
5688 		min_valid_off = -state->allocated_stack;
5689 
5690 	if (off < min_valid_off || off > -1)
5691 		return -EACCES;
5692 	return 0;
5693 }
5694 
5695 /* Check that the stack access at 'regno + off' falls within the maximum stack
5696  * bounds.
5697  *
5698  * 'off' includes `regno->offset`, but not its dynamic part (if any).
5699  */
5700 static int check_stack_access_within_bounds(
5701 		struct bpf_verifier_env *env,
5702 		int regno, int off, int access_size,
5703 		enum bpf_access_src src, enum bpf_access_type type)
5704 {
5705 	struct bpf_reg_state *regs = cur_regs(env);
5706 	struct bpf_reg_state *reg = regs + regno;
5707 	struct bpf_func_state *state = func(env, reg);
5708 	int min_off, max_off;
5709 	int err;
5710 	char *err_extra;
5711 
5712 	if (src == ACCESS_HELPER)
5713 		/* We don't know if helpers are reading or writing (or both). */
5714 		err_extra = " indirect access to";
5715 	else if (type == BPF_READ)
5716 		err_extra = " read from";
5717 	else
5718 		err_extra = " write to";
5719 
5720 	if (tnum_is_const(reg->var_off)) {
5721 		min_off = reg->var_off.value + off;
5722 		if (access_size > 0)
5723 			max_off = min_off + access_size - 1;
5724 		else
5725 			max_off = min_off;
5726 	} else {
5727 		if (reg->smax_value >= BPF_MAX_VAR_OFF ||
5728 		    reg->smin_value <= -BPF_MAX_VAR_OFF) {
5729 			verbose(env, "invalid unbounded variable-offset%s stack R%d\n",
5730 				err_extra, regno);
5731 			return -EACCES;
5732 		}
5733 		min_off = reg->smin_value + off;
5734 		if (access_size > 0)
5735 			max_off = reg->smax_value + off + access_size - 1;
5736 		else
5737 			max_off = min_off;
5738 	}
5739 
5740 	err = check_stack_slot_within_bounds(min_off, state, type);
5741 	if (!err)
5742 		err = check_stack_slot_within_bounds(max_off, state, type);
5743 
5744 	if (err) {
5745 		if (tnum_is_const(reg->var_off)) {
5746 			verbose(env, "invalid%s stack R%d off=%d size=%d\n",
5747 				err_extra, regno, off, access_size);
5748 		} else {
5749 			char tn_buf[48];
5750 
5751 			tnum_strn(tn_buf, sizeof(tn_buf), reg->var_off);
5752 			verbose(env, "invalid variable-offset%s stack R%d var_off=%s size=%d\n",
5753 				err_extra, regno, tn_buf, access_size);
5754 		}
5755 	}
5756 	return err;
5757 }
5758 
5759 /* check whether memory at (regno + off) is accessible for t = (read | write)
5760  * if t==write, value_regno is a register which value is stored into memory
5761  * if t==read, value_regno is a register which will receive the value from memory
5762  * if t==write && value_regno==-1, some unknown value is stored into memory
5763  * if t==read && value_regno==-1, don't care what we read from memory
5764  */
5765 static int check_mem_access(struct bpf_verifier_env *env, int insn_idx, u32 regno,
5766 			    int off, int bpf_size, enum bpf_access_type t,
5767 			    int value_regno, bool strict_alignment_once)
5768 {
5769 	struct bpf_reg_state *regs = cur_regs(env);
5770 	struct bpf_reg_state *reg = regs + regno;
5771 	struct bpf_func_state *state;
5772 	int size, err = 0;
5773 
5774 	size = bpf_size_to_bytes(bpf_size);
5775 	if (size < 0)
5776 		return size;
5777 
5778 	/* alignment checks will add in reg->off themselves */
5779 	err = check_ptr_alignment(env, reg, off, size, strict_alignment_once);
5780 	if (err)
5781 		return err;
5782 
5783 	/* for access checks, reg->off is just part of off */
5784 	off += reg->off;
5785 
5786 	if (reg->type == PTR_TO_MAP_KEY) {
5787 		if (t == BPF_WRITE) {
5788 			verbose(env, "write to change key R%d not allowed\n", regno);
5789 			return -EACCES;
5790 		}
5791 
5792 		err = check_mem_region_access(env, regno, off, size,
5793 					      reg->map_ptr->key_size, false);
5794 		if (err)
5795 			return err;
5796 		if (value_regno >= 0)
5797 			mark_reg_unknown(env, regs, value_regno);
5798 	} else if (reg->type == PTR_TO_MAP_VALUE) {
5799 		struct btf_field *kptr_field = NULL;
5800 
5801 		if (t == BPF_WRITE && value_regno >= 0 &&
5802 		    is_pointer_value(env, value_regno)) {
5803 			verbose(env, "R%d leaks addr into map\n", value_regno);
5804 			return -EACCES;
5805 		}
5806 		err = check_map_access_type(env, regno, off, size, t);
5807 		if (err)
5808 			return err;
5809 		err = check_map_access(env, regno, off, size, false, ACCESS_DIRECT);
5810 		if (err)
5811 			return err;
5812 		if (tnum_is_const(reg->var_off))
5813 			kptr_field = btf_record_find(reg->map_ptr->record,
5814 						     off + reg->var_off.value, BPF_KPTR);
5815 		if (kptr_field) {
5816 			err = check_map_kptr_access(env, regno, value_regno, insn_idx, kptr_field);
5817 		} else if (t == BPF_READ && value_regno >= 0) {
5818 			struct bpf_map *map = reg->map_ptr;
5819 
5820 			/* if map is read-only, track its contents as scalars */
5821 			if (tnum_is_const(reg->var_off) &&
5822 			    bpf_map_is_rdonly(map) &&
5823 			    map->ops->map_direct_value_addr) {
5824 				int map_off = off + reg->var_off.value;
5825 				u64 val = 0;
5826 
5827 				err = bpf_map_direct_read(map, map_off, size,
5828 							  &val);
5829 				if (err)
5830 					return err;
5831 
5832 				regs[value_regno].type = SCALAR_VALUE;
5833 				__mark_reg_known(&regs[value_regno], val);
5834 			} else {
5835 				mark_reg_unknown(env, regs, value_regno);
5836 			}
5837 		}
5838 	} else if (base_type(reg->type) == PTR_TO_MEM) {
5839 		bool rdonly_mem = type_is_rdonly_mem(reg->type);
5840 
5841 		if (type_may_be_null(reg->type)) {
5842 			verbose(env, "R%d invalid mem access '%s'\n", regno,
5843 				reg_type_str(env, reg->type));
5844 			return -EACCES;
5845 		}
5846 
5847 		if (t == BPF_WRITE && rdonly_mem) {
5848 			verbose(env, "R%d cannot write into %s\n",
5849 				regno, reg_type_str(env, reg->type));
5850 			return -EACCES;
5851 		}
5852 
5853 		if (t == BPF_WRITE && value_regno >= 0 &&
5854 		    is_pointer_value(env, value_regno)) {
5855 			verbose(env, "R%d leaks addr into mem\n", value_regno);
5856 			return -EACCES;
5857 		}
5858 
5859 		err = check_mem_region_access(env, regno, off, size,
5860 					      reg->mem_size, false);
5861 		if (!err && value_regno >= 0 && (t == BPF_READ || rdonly_mem))
5862 			mark_reg_unknown(env, regs, value_regno);
5863 	} else if (reg->type == PTR_TO_CTX) {
5864 		enum bpf_reg_type reg_type = SCALAR_VALUE;
5865 		struct btf *btf = NULL;
5866 		u32 btf_id = 0;
5867 
5868 		if (t == BPF_WRITE && value_regno >= 0 &&
5869 		    is_pointer_value(env, value_regno)) {
5870 			verbose(env, "R%d leaks addr into ctx\n", value_regno);
5871 			return -EACCES;
5872 		}
5873 
5874 		err = check_ptr_off_reg(env, reg, regno);
5875 		if (err < 0)
5876 			return err;
5877 
5878 		err = check_ctx_access(env, insn_idx, off, size, t, &reg_type, &btf,
5879 				       &btf_id);
5880 		if (err)
5881 			verbose_linfo(env, insn_idx, "; ");
5882 		if (!err && t == BPF_READ && value_regno >= 0) {
5883 			/* ctx access returns either a scalar, or a
5884 			 * PTR_TO_PACKET[_META,_END]. In the latter
5885 			 * case, we know the offset is zero.
5886 			 */
5887 			if (reg_type == SCALAR_VALUE) {
5888 				mark_reg_unknown(env, regs, value_regno);
5889 			} else {
5890 				mark_reg_known_zero(env, regs,
5891 						    value_regno);
5892 				if (type_may_be_null(reg_type))
5893 					regs[value_regno].id = ++env->id_gen;
5894 				/* A load of ctx field could have different
5895 				 * actual load size with the one encoded in the
5896 				 * insn. When the dst is PTR, it is for sure not
5897 				 * a sub-register.
5898 				 */
5899 				regs[value_regno].subreg_def = DEF_NOT_SUBREG;
5900 				if (base_type(reg_type) == PTR_TO_BTF_ID) {
5901 					regs[value_regno].btf = btf;
5902 					regs[value_regno].btf_id = btf_id;
5903 				}
5904 			}
5905 			regs[value_regno].type = reg_type;
5906 		}
5907 
5908 	} else if (reg->type == PTR_TO_STACK) {
5909 		/* Basic bounds checks. */
5910 		err = check_stack_access_within_bounds(env, regno, off, size, ACCESS_DIRECT, t);
5911 		if (err)
5912 			return err;
5913 
5914 		state = func(env, reg);
5915 		err = update_stack_depth(env, state, off);
5916 		if (err)
5917 			return err;
5918 
5919 		if (t == BPF_READ)
5920 			err = check_stack_read(env, regno, off, size,
5921 					       value_regno);
5922 		else
5923 			err = check_stack_write(env, regno, off, size,
5924 						value_regno, insn_idx);
5925 	} else if (reg_is_pkt_pointer(reg)) {
5926 		if (t == BPF_WRITE && !may_access_direct_pkt_data(env, NULL, t)) {
5927 			verbose(env, "cannot write into packet\n");
5928 			return -EACCES;
5929 		}
5930 		if (t == BPF_WRITE && value_regno >= 0 &&
5931 		    is_pointer_value(env, value_regno)) {
5932 			verbose(env, "R%d leaks addr into packet\n",
5933 				value_regno);
5934 			return -EACCES;
5935 		}
5936 		err = check_packet_access(env, regno, off, size, false);
5937 		if (!err && t == BPF_READ && value_regno >= 0)
5938 			mark_reg_unknown(env, regs, value_regno);
5939 	} else if (reg->type == PTR_TO_FLOW_KEYS) {
5940 		if (t == BPF_WRITE && value_regno >= 0 &&
5941 		    is_pointer_value(env, value_regno)) {
5942 			verbose(env, "R%d leaks addr into flow keys\n",
5943 				value_regno);
5944 			return -EACCES;
5945 		}
5946 
5947 		err = check_flow_keys_access(env, off, size);
5948 		if (!err && t == BPF_READ && value_regno >= 0)
5949 			mark_reg_unknown(env, regs, value_regno);
5950 	} else if (type_is_sk_pointer(reg->type)) {
5951 		if (t == BPF_WRITE) {
5952 			verbose(env, "R%d cannot write into %s\n",
5953 				regno, reg_type_str(env, reg->type));
5954 			return -EACCES;
5955 		}
5956 		err = check_sock_access(env, insn_idx, regno, off, size, t);
5957 		if (!err && value_regno >= 0)
5958 			mark_reg_unknown(env, regs, value_regno);
5959 	} else if (reg->type == PTR_TO_TP_BUFFER) {
5960 		err = check_tp_buffer_access(env, reg, regno, off, size);
5961 		if (!err && t == BPF_READ && value_regno >= 0)
5962 			mark_reg_unknown(env, regs, value_regno);
5963 	} else if (base_type(reg->type) == PTR_TO_BTF_ID &&
5964 		   !type_may_be_null(reg->type)) {
5965 		err = check_ptr_to_btf_access(env, regs, regno, off, size, t,
5966 					      value_regno);
5967 	} else if (reg->type == CONST_PTR_TO_MAP) {
5968 		err = check_ptr_to_map_access(env, regs, regno, off, size, t,
5969 					      value_regno);
5970 	} else if (base_type(reg->type) == PTR_TO_BUF) {
5971 		bool rdonly_mem = type_is_rdonly_mem(reg->type);
5972 		u32 *max_access;
5973 
5974 		if (rdonly_mem) {
5975 			if (t == BPF_WRITE) {
5976 				verbose(env, "R%d cannot write into %s\n",
5977 					regno, reg_type_str(env, reg->type));
5978 				return -EACCES;
5979 			}
5980 			max_access = &env->prog->aux->max_rdonly_access;
5981 		} else {
5982 			max_access = &env->prog->aux->max_rdwr_access;
5983 		}
5984 
5985 		err = check_buffer_access(env, reg, regno, off, size, false,
5986 					  max_access);
5987 
5988 		if (!err && value_regno >= 0 && (rdonly_mem || t == BPF_READ))
5989 			mark_reg_unknown(env, regs, value_regno);
5990 	} else {
5991 		verbose(env, "R%d invalid mem access '%s'\n", regno,
5992 			reg_type_str(env, reg->type));
5993 		return -EACCES;
5994 	}
5995 
5996 	if (!err && size < BPF_REG_SIZE && value_regno >= 0 && t == BPF_READ &&
5997 	    regs[value_regno].type == SCALAR_VALUE) {
5998 		/* b/h/w load zero-extends, mark upper bits as known 0 */
5999 		coerce_reg_to_size(&regs[value_regno], size);
6000 	}
6001 	return err;
6002 }
6003 
6004 static int check_atomic(struct bpf_verifier_env *env, int insn_idx, struct bpf_insn *insn)
6005 {
6006 	int load_reg;
6007 	int err;
6008 
6009 	switch (insn->imm) {
6010 	case BPF_ADD:
6011 	case BPF_ADD | BPF_FETCH:
6012 	case BPF_AND:
6013 	case BPF_AND | BPF_FETCH:
6014 	case BPF_OR:
6015 	case BPF_OR | BPF_FETCH:
6016 	case BPF_XOR:
6017 	case BPF_XOR | BPF_FETCH:
6018 	case BPF_XCHG:
6019 	case BPF_CMPXCHG:
6020 		break;
6021 	default:
6022 		verbose(env, "BPF_ATOMIC uses invalid atomic opcode %02x\n", insn->imm);
6023 		return -EINVAL;
6024 	}
6025 
6026 	if (BPF_SIZE(insn->code) != BPF_W && BPF_SIZE(insn->code) != BPF_DW) {
6027 		verbose(env, "invalid atomic operand size\n");
6028 		return -EINVAL;
6029 	}
6030 
6031 	/* check src1 operand */
6032 	err = check_reg_arg(env, insn->src_reg, SRC_OP);
6033 	if (err)
6034 		return err;
6035 
6036 	/* check src2 operand */
6037 	err = check_reg_arg(env, insn->dst_reg, SRC_OP);
6038 	if (err)
6039 		return err;
6040 
6041 	if (insn->imm == BPF_CMPXCHG) {
6042 		/* Check comparison of R0 with memory location */
6043 		const u32 aux_reg = BPF_REG_0;
6044 
6045 		err = check_reg_arg(env, aux_reg, SRC_OP);
6046 		if (err)
6047 			return err;
6048 
6049 		if (is_pointer_value(env, aux_reg)) {
6050 			verbose(env, "R%d leaks addr into mem\n", aux_reg);
6051 			return -EACCES;
6052 		}
6053 	}
6054 
6055 	if (is_pointer_value(env, insn->src_reg)) {
6056 		verbose(env, "R%d leaks addr into mem\n", insn->src_reg);
6057 		return -EACCES;
6058 	}
6059 
6060 	if (is_ctx_reg(env, insn->dst_reg) ||
6061 	    is_pkt_reg(env, insn->dst_reg) ||
6062 	    is_flow_key_reg(env, insn->dst_reg) ||
6063 	    is_sk_reg(env, insn->dst_reg)) {
6064 		verbose(env, "BPF_ATOMIC stores into R%d %s is not allowed\n",
6065 			insn->dst_reg,
6066 			reg_type_str(env, reg_state(env, insn->dst_reg)->type));
6067 		return -EACCES;
6068 	}
6069 
6070 	if (insn->imm & BPF_FETCH) {
6071 		if (insn->imm == BPF_CMPXCHG)
6072 			load_reg = BPF_REG_0;
6073 		else
6074 			load_reg = insn->src_reg;
6075 
6076 		/* check and record load of old value */
6077 		err = check_reg_arg(env, load_reg, DST_OP);
6078 		if (err)
6079 			return err;
6080 	} else {
6081 		/* This instruction accesses a memory location but doesn't
6082 		 * actually load it into a register.
6083 		 */
6084 		load_reg = -1;
6085 	}
6086 
6087 	/* Check whether we can read the memory, with second call for fetch
6088 	 * case to simulate the register fill.
6089 	 */
6090 	err = check_mem_access(env, insn_idx, insn->dst_reg, insn->off,
6091 			       BPF_SIZE(insn->code), BPF_READ, -1, true);
6092 	if (!err && load_reg >= 0)
6093 		err = check_mem_access(env, insn_idx, insn->dst_reg, insn->off,
6094 				       BPF_SIZE(insn->code), BPF_READ, load_reg,
6095 				       true);
6096 	if (err)
6097 		return err;
6098 
6099 	/* Check whether we can write into the same memory. */
6100 	err = check_mem_access(env, insn_idx, insn->dst_reg, insn->off,
6101 			       BPF_SIZE(insn->code), BPF_WRITE, -1, true);
6102 	if (err)
6103 		return err;
6104 
6105 	return 0;
6106 }
6107 
6108 /* When register 'regno' is used to read the stack (either directly or through
6109  * a helper function) make sure that it's within stack boundary and, depending
6110  * on the access type, that all elements of the stack are initialized.
6111  *
6112  * 'off' includes 'regno->off', but not its dynamic part (if any).
6113  *
6114  * All registers that have been spilled on the stack in the slots within the
6115  * read offsets are marked as read.
6116  */
6117 static int check_stack_range_initialized(
6118 		struct bpf_verifier_env *env, int regno, int off,
6119 		int access_size, bool zero_size_allowed,
6120 		enum bpf_access_src type, struct bpf_call_arg_meta *meta)
6121 {
6122 	struct bpf_reg_state *reg = reg_state(env, regno);
6123 	struct bpf_func_state *state = func(env, reg);
6124 	int err, min_off, max_off, i, j, slot, spi;
6125 	char *err_extra = type == ACCESS_HELPER ? " indirect" : "";
6126 	enum bpf_access_type bounds_check_type;
6127 	/* Some accesses can write anything into the stack, others are
6128 	 * read-only.
6129 	 */
6130 	bool clobber = false;
6131 
6132 	if (access_size == 0 && !zero_size_allowed) {
6133 		verbose(env, "invalid zero-sized read\n");
6134 		return -EACCES;
6135 	}
6136 
6137 	if (type == ACCESS_HELPER) {
6138 		/* The bounds checks for writes are more permissive than for
6139 		 * reads. However, if raw_mode is not set, we'll do extra
6140 		 * checks below.
6141 		 */
6142 		bounds_check_type = BPF_WRITE;
6143 		clobber = true;
6144 	} else {
6145 		bounds_check_type = BPF_READ;
6146 	}
6147 	err = check_stack_access_within_bounds(env, regno, off, access_size,
6148 					       type, bounds_check_type);
6149 	if (err)
6150 		return err;
6151 
6152 
6153 	if (tnum_is_const(reg->var_off)) {
6154 		min_off = max_off = reg->var_off.value + off;
6155 	} else {
6156 		/* Variable offset is prohibited for unprivileged mode for
6157 		 * simplicity since it requires corresponding support in
6158 		 * Spectre masking for stack ALU.
6159 		 * See also retrieve_ptr_limit().
6160 		 */
6161 		if (!env->bypass_spec_v1) {
6162 			char tn_buf[48];
6163 
6164 			tnum_strn(tn_buf, sizeof(tn_buf), reg->var_off);
6165 			verbose(env, "R%d%s variable offset stack access prohibited for !root, var_off=%s\n",
6166 				regno, err_extra, tn_buf);
6167 			return -EACCES;
6168 		}
6169 		/* Only initialized buffer on stack is allowed to be accessed
6170 		 * with variable offset. With uninitialized buffer it's hard to
6171 		 * guarantee that whole memory is marked as initialized on
6172 		 * helper return since specific bounds are unknown what may
6173 		 * cause uninitialized stack leaking.
6174 		 */
6175 		if (meta && meta->raw_mode)
6176 			meta = NULL;
6177 
6178 		min_off = reg->smin_value + off;
6179 		max_off = reg->smax_value + off;
6180 	}
6181 
6182 	if (meta && meta->raw_mode) {
6183 		/* Ensure we won't be overwriting dynptrs when simulating byte
6184 		 * by byte access in check_helper_call using meta.access_size.
6185 		 * This would be a problem if we have a helper in the future
6186 		 * which takes:
6187 		 *
6188 		 *	helper(uninit_mem, len, dynptr)
6189 		 *
6190 		 * Now, uninint_mem may overlap with dynptr pointer. Hence, it
6191 		 * may end up writing to dynptr itself when touching memory from
6192 		 * arg 1. This can be relaxed on a case by case basis for known
6193 		 * safe cases, but reject due to the possibilitiy of aliasing by
6194 		 * default.
6195 		 */
6196 		for (i = min_off; i < max_off + access_size; i++) {
6197 			int stack_off = -i - 1;
6198 
6199 			spi = __get_spi(i);
6200 			/* raw_mode may write past allocated_stack */
6201 			if (state->allocated_stack <= stack_off)
6202 				continue;
6203 			if (state->stack[spi].slot_type[stack_off % BPF_REG_SIZE] == STACK_DYNPTR) {
6204 				verbose(env, "potential write to dynptr at off=%d disallowed\n", i);
6205 				return -EACCES;
6206 			}
6207 		}
6208 		meta->access_size = access_size;
6209 		meta->regno = regno;
6210 		return 0;
6211 	}
6212 
6213 	for (i = min_off; i < max_off + access_size; i++) {
6214 		u8 *stype;
6215 
6216 		slot = -i - 1;
6217 		spi = slot / BPF_REG_SIZE;
6218 		if (state->allocated_stack <= slot)
6219 			goto err;
6220 		stype = &state->stack[spi].slot_type[slot % BPF_REG_SIZE];
6221 		if (*stype == STACK_MISC)
6222 			goto mark;
6223 		if ((*stype == STACK_ZERO) ||
6224 		    (*stype == STACK_INVALID && env->allow_uninit_stack)) {
6225 			if (clobber) {
6226 				/* helper can write anything into the stack */
6227 				*stype = STACK_MISC;
6228 			}
6229 			goto mark;
6230 		}
6231 
6232 		if (is_spilled_reg(&state->stack[spi]) &&
6233 		    (state->stack[spi].spilled_ptr.type == SCALAR_VALUE ||
6234 		     env->allow_ptr_leaks)) {
6235 			if (clobber) {
6236 				__mark_reg_unknown(env, &state->stack[spi].spilled_ptr);
6237 				for (j = 0; j < BPF_REG_SIZE; j++)
6238 					scrub_spilled_slot(&state->stack[spi].slot_type[j]);
6239 			}
6240 			goto mark;
6241 		}
6242 
6243 err:
6244 		if (tnum_is_const(reg->var_off)) {
6245 			verbose(env, "invalid%s read from stack R%d off %d+%d size %d\n",
6246 				err_extra, regno, min_off, i - min_off, access_size);
6247 		} else {
6248 			char tn_buf[48];
6249 
6250 			tnum_strn(tn_buf, sizeof(tn_buf), reg->var_off);
6251 			verbose(env, "invalid%s read from stack R%d var_off %s+%d size %d\n",
6252 				err_extra, regno, tn_buf, i - min_off, access_size);
6253 		}
6254 		return -EACCES;
6255 mark:
6256 		/* reading any byte out of 8-byte 'spill_slot' will cause
6257 		 * the whole slot to be marked as 'read'
6258 		 */
6259 		mark_reg_read(env, &state->stack[spi].spilled_ptr,
6260 			      state->stack[spi].spilled_ptr.parent,
6261 			      REG_LIVE_READ64);
6262 		/* We do not set REG_LIVE_WRITTEN for stack slot, as we can not
6263 		 * be sure that whether stack slot is written to or not. Hence,
6264 		 * we must still conservatively propagate reads upwards even if
6265 		 * helper may write to the entire memory range.
6266 		 */
6267 	}
6268 	return update_stack_depth(env, state, min_off);
6269 }
6270 
6271 static int check_helper_mem_access(struct bpf_verifier_env *env, int regno,
6272 				   int access_size, bool zero_size_allowed,
6273 				   struct bpf_call_arg_meta *meta)
6274 {
6275 	struct bpf_reg_state *regs = cur_regs(env), *reg = &regs[regno];
6276 	u32 *max_access;
6277 
6278 	switch (base_type(reg->type)) {
6279 	case PTR_TO_PACKET:
6280 	case PTR_TO_PACKET_META:
6281 		return check_packet_access(env, regno, reg->off, access_size,
6282 					   zero_size_allowed);
6283 	case PTR_TO_MAP_KEY:
6284 		if (meta && meta->raw_mode) {
6285 			verbose(env, "R%d cannot write into %s\n", regno,
6286 				reg_type_str(env, reg->type));
6287 			return -EACCES;
6288 		}
6289 		return check_mem_region_access(env, regno, reg->off, access_size,
6290 					       reg->map_ptr->key_size, false);
6291 	case PTR_TO_MAP_VALUE:
6292 		if (check_map_access_type(env, regno, reg->off, access_size,
6293 					  meta && meta->raw_mode ? BPF_WRITE :
6294 					  BPF_READ))
6295 			return -EACCES;
6296 		return check_map_access(env, regno, reg->off, access_size,
6297 					zero_size_allowed, ACCESS_HELPER);
6298 	case PTR_TO_MEM:
6299 		if (type_is_rdonly_mem(reg->type)) {
6300 			if (meta && meta->raw_mode) {
6301 				verbose(env, "R%d cannot write into %s\n", regno,
6302 					reg_type_str(env, reg->type));
6303 				return -EACCES;
6304 			}
6305 		}
6306 		return check_mem_region_access(env, regno, reg->off,
6307 					       access_size, reg->mem_size,
6308 					       zero_size_allowed);
6309 	case PTR_TO_BUF:
6310 		if (type_is_rdonly_mem(reg->type)) {
6311 			if (meta && meta->raw_mode) {
6312 				verbose(env, "R%d cannot write into %s\n", regno,
6313 					reg_type_str(env, reg->type));
6314 				return -EACCES;
6315 			}
6316 
6317 			max_access = &env->prog->aux->max_rdonly_access;
6318 		} else {
6319 			max_access = &env->prog->aux->max_rdwr_access;
6320 		}
6321 		return check_buffer_access(env, reg, regno, reg->off,
6322 					   access_size, zero_size_allowed,
6323 					   max_access);
6324 	case PTR_TO_STACK:
6325 		return check_stack_range_initialized(
6326 				env,
6327 				regno, reg->off, access_size,
6328 				zero_size_allowed, ACCESS_HELPER, meta);
6329 	case PTR_TO_BTF_ID:
6330 		return check_ptr_to_btf_access(env, regs, regno, reg->off,
6331 					       access_size, BPF_READ, -1);
6332 	case PTR_TO_CTX:
6333 		/* in case the function doesn't know how to access the context,
6334 		 * (because we are in a program of type SYSCALL for example), we
6335 		 * can not statically check its size.
6336 		 * Dynamically check it now.
6337 		 */
6338 		if (!env->ops->convert_ctx_access) {
6339 			enum bpf_access_type atype = meta && meta->raw_mode ? BPF_WRITE : BPF_READ;
6340 			int offset = access_size - 1;
6341 
6342 			/* Allow zero-byte read from PTR_TO_CTX */
6343 			if (access_size == 0)
6344 				return zero_size_allowed ? 0 : -EACCES;
6345 
6346 			return check_mem_access(env, env->insn_idx, regno, offset, BPF_B,
6347 						atype, -1, false);
6348 		}
6349 
6350 		fallthrough;
6351 	default: /* scalar_value or invalid ptr */
6352 		/* Allow zero-byte read from NULL, regardless of pointer type */
6353 		if (zero_size_allowed && access_size == 0 &&
6354 		    register_is_null(reg))
6355 			return 0;
6356 
6357 		verbose(env, "R%d type=%s ", regno,
6358 			reg_type_str(env, reg->type));
6359 		verbose(env, "expected=%s\n", reg_type_str(env, PTR_TO_STACK));
6360 		return -EACCES;
6361 	}
6362 }
6363 
6364 static int check_mem_size_reg(struct bpf_verifier_env *env,
6365 			      struct bpf_reg_state *reg, u32 regno,
6366 			      bool zero_size_allowed,
6367 			      struct bpf_call_arg_meta *meta)
6368 {
6369 	int err;
6370 
6371 	/* This is used to refine r0 return value bounds for helpers
6372 	 * that enforce this value as an upper bound on return values.
6373 	 * See do_refine_retval_range() for helpers that can refine
6374 	 * the return value. C type of helper is u32 so we pull register
6375 	 * bound from umax_value however, if negative verifier errors
6376 	 * out. Only upper bounds can be learned because retval is an
6377 	 * int type and negative retvals are allowed.
6378 	 */
6379 	meta->msize_max_value = reg->umax_value;
6380 
6381 	/* The register is SCALAR_VALUE; the access check
6382 	 * happens using its boundaries.
6383 	 */
6384 	if (!tnum_is_const(reg->var_off))
6385 		/* For unprivileged variable accesses, disable raw
6386 		 * mode so that the program is required to
6387 		 * initialize all the memory that the helper could
6388 		 * just partially fill up.
6389 		 */
6390 		meta = NULL;
6391 
6392 	if (reg->smin_value < 0) {
6393 		verbose(env, "R%d min value is negative, either use unsigned or 'var &= const'\n",
6394 			regno);
6395 		return -EACCES;
6396 	}
6397 
6398 	if (reg->umin_value == 0) {
6399 		err = check_helper_mem_access(env, regno - 1, 0,
6400 					      zero_size_allowed,
6401 					      meta);
6402 		if (err)
6403 			return err;
6404 	}
6405 
6406 	if (reg->umax_value >= BPF_MAX_VAR_SIZ) {
6407 		verbose(env, "R%d unbounded memory access, use 'var &= const' or 'if (var < const)'\n",
6408 			regno);
6409 		return -EACCES;
6410 	}
6411 	err = check_helper_mem_access(env, regno - 1,
6412 				      reg->umax_value,
6413 				      zero_size_allowed, meta);
6414 	if (!err)
6415 		err = mark_chain_precision(env, regno);
6416 	return err;
6417 }
6418 
6419 int check_mem_reg(struct bpf_verifier_env *env, struct bpf_reg_state *reg,
6420 		   u32 regno, u32 mem_size)
6421 {
6422 	bool may_be_null = type_may_be_null(reg->type);
6423 	struct bpf_reg_state saved_reg;
6424 	struct bpf_call_arg_meta meta;
6425 	int err;
6426 
6427 	if (register_is_null(reg))
6428 		return 0;
6429 
6430 	memset(&meta, 0, sizeof(meta));
6431 	/* Assuming that the register contains a value check if the memory
6432 	 * access is safe. Temporarily save and restore the register's state as
6433 	 * the conversion shouldn't be visible to a caller.
6434 	 */
6435 	if (may_be_null) {
6436 		saved_reg = *reg;
6437 		mark_ptr_not_null_reg(reg);
6438 	}
6439 
6440 	err = check_helper_mem_access(env, regno, mem_size, true, &meta);
6441 	/* Check access for BPF_WRITE */
6442 	meta.raw_mode = true;
6443 	err = err ?: check_helper_mem_access(env, regno, mem_size, true, &meta);
6444 
6445 	if (may_be_null)
6446 		*reg = saved_reg;
6447 
6448 	return err;
6449 }
6450 
6451 static int check_kfunc_mem_size_reg(struct bpf_verifier_env *env, struct bpf_reg_state *reg,
6452 				    u32 regno)
6453 {
6454 	struct bpf_reg_state *mem_reg = &cur_regs(env)[regno - 1];
6455 	bool may_be_null = type_may_be_null(mem_reg->type);
6456 	struct bpf_reg_state saved_reg;
6457 	struct bpf_call_arg_meta meta;
6458 	int err;
6459 
6460 	WARN_ON_ONCE(regno < BPF_REG_2 || regno > BPF_REG_5);
6461 
6462 	memset(&meta, 0, sizeof(meta));
6463 
6464 	if (may_be_null) {
6465 		saved_reg = *mem_reg;
6466 		mark_ptr_not_null_reg(mem_reg);
6467 	}
6468 
6469 	err = check_mem_size_reg(env, reg, regno, true, &meta);
6470 	/* Check access for BPF_WRITE */
6471 	meta.raw_mode = true;
6472 	err = err ?: check_mem_size_reg(env, reg, regno, true, &meta);
6473 
6474 	if (may_be_null)
6475 		*mem_reg = saved_reg;
6476 	return err;
6477 }
6478 
6479 /* Implementation details:
6480  * bpf_map_lookup returns PTR_TO_MAP_VALUE_OR_NULL.
6481  * bpf_obj_new returns PTR_TO_BTF_ID | MEM_ALLOC | PTR_MAYBE_NULL.
6482  * Two bpf_map_lookups (even with the same key) will have different reg->id.
6483  * Two separate bpf_obj_new will also have different reg->id.
6484  * For traditional PTR_TO_MAP_VALUE or PTR_TO_BTF_ID | MEM_ALLOC, the verifier
6485  * clears reg->id after value_or_null->value transition, since the verifier only
6486  * cares about the range of access to valid map value pointer and doesn't care
6487  * about actual address of the map element.
6488  * For maps with 'struct bpf_spin_lock' inside map value the verifier keeps
6489  * reg->id > 0 after value_or_null->value transition. By doing so
6490  * two bpf_map_lookups will be considered two different pointers that
6491  * point to different bpf_spin_locks. Likewise for pointers to allocated objects
6492  * returned from bpf_obj_new.
6493  * The verifier allows taking only one bpf_spin_lock at a time to avoid
6494  * dead-locks.
6495  * Since only one bpf_spin_lock is allowed the checks are simpler than
6496  * reg_is_refcounted() logic. The verifier needs to remember only
6497  * one spin_lock instead of array of acquired_refs.
6498  * cur_state->active_lock remembers which map value element or allocated
6499  * object got locked and clears it after bpf_spin_unlock.
6500  */
6501 static int process_spin_lock(struct bpf_verifier_env *env, int regno,
6502 			     bool is_lock)
6503 {
6504 	struct bpf_reg_state *regs = cur_regs(env), *reg = &regs[regno];
6505 	struct bpf_verifier_state *cur = env->cur_state;
6506 	bool is_const = tnum_is_const(reg->var_off);
6507 	u64 val = reg->var_off.value;
6508 	struct bpf_map *map = NULL;
6509 	struct btf *btf = NULL;
6510 	struct btf_record *rec;
6511 
6512 	if (!is_const) {
6513 		verbose(env,
6514 			"R%d doesn't have constant offset. bpf_spin_lock has to be at the constant offset\n",
6515 			regno);
6516 		return -EINVAL;
6517 	}
6518 	if (reg->type == PTR_TO_MAP_VALUE) {
6519 		map = reg->map_ptr;
6520 		if (!map->btf) {
6521 			verbose(env,
6522 				"map '%s' has to have BTF in order to use bpf_spin_lock\n",
6523 				map->name);
6524 			return -EINVAL;
6525 		}
6526 	} else {
6527 		btf = reg->btf;
6528 	}
6529 
6530 	rec = reg_btf_record(reg);
6531 	if (!btf_record_has_field(rec, BPF_SPIN_LOCK)) {
6532 		verbose(env, "%s '%s' has no valid bpf_spin_lock\n", map ? "map" : "local",
6533 			map ? map->name : "kptr");
6534 		return -EINVAL;
6535 	}
6536 	if (rec->spin_lock_off != val + reg->off) {
6537 		verbose(env, "off %lld doesn't point to 'struct bpf_spin_lock' that is at %d\n",
6538 			val + reg->off, rec->spin_lock_off);
6539 		return -EINVAL;
6540 	}
6541 	if (is_lock) {
6542 		if (cur->active_lock.ptr) {
6543 			verbose(env,
6544 				"Locking two bpf_spin_locks are not allowed\n");
6545 			return -EINVAL;
6546 		}
6547 		if (map)
6548 			cur->active_lock.ptr = map;
6549 		else
6550 			cur->active_lock.ptr = btf;
6551 		cur->active_lock.id = reg->id;
6552 	} else {
6553 		void *ptr;
6554 
6555 		if (map)
6556 			ptr = map;
6557 		else
6558 			ptr = btf;
6559 
6560 		if (!cur->active_lock.ptr) {
6561 			verbose(env, "bpf_spin_unlock without taking a lock\n");
6562 			return -EINVAL;
6563 		}
6564 		if (cur->active_lock.ptr != ptr ||
6565 		    cur->active_lock.id != reg->id) {
6566 			verbose(env, "bpf_spin_unlock of different lock\n");
6567 			return -EINVAL;
6568 		}
6569 
6570 		invalidate_non_owning_refs(env);
6571 
6572 		cur->active_lock.ptr = NULL;
6573 		cur->active_lock.id = 0;
6574 	}
6575 	return 0;
6576 }
6577 
6578 static int process_timer_func(struct bpf_verifier_env *env, int regno,
6579 			      struct bpf_call_arg_meta *meta)
6580 {
6581 	struct bpf_reg_state *regs = cur_regs(env), *reg = &regs[regno];
6582 	bool is_const = tnum_is_const(reg->var_off);
6583 	struct bpf_map *map = reg->map_ptr;
6584 	u64 val = reg->var_off.value;
6585 
6586 	if (!is_const) {
6587 		verbose(env,
6588 			"R%d doesn't have constant offset. bpf_timer has to be at the constant offset\n",
6589 			regno);
6590 		return -EINVAL;
6591 	}
6592 	if (!map->btf) {
6593 		verbose(env, "map '%s' has to have BTF in order to use bpf_timer\n",
6594 			map->name);
6595 		return -EINVAL;
6596 	}
6597 	if (!btf_record_has_field(map->record, BPF_TIMER)) {
6598 		verbose(env, "map '%s' has no valid bpf_timer\n", map->name);
6599 		return -EINVAL;
6600 	}
6601 	if (map->record->timer_off != val + reg->off) {
6602 		verbose(env, "off %lld doesn't point to 'struct bpf_timer' that is at %d\n",
6603 			val + reg->off, map->record->timer_off);
6604 		return -EINVAL;
6605 	}
6606 	if (meta->map_ptr) {
6607 		verbose(env, "verifier bug. Two map pointers in a timer helper\n");
6608 		return -EFAULT;
6609 	}
6610 	meta->map_uid = reg->map_uid;
6611 	meta->map_ptr = map;
6612 	return 0;
6613 }
6614 
6615 static int process_kptr_func(struct bpf_verifier_env *env, int regno,
6616 			     struct bpf_call_arg_meta *meta)
6617 {
6618 	struct bpf_reg_state *regs = cur_regs(env), *reg = &regs[regno];
6619 	struct bpf_map *map_ptr = reg->map_ptr;
6620 	struct btf_field *kptr_field;
6621 	u32 kptr_off;
6622 
6623 	if (!tnum_is_const(reg->var_off)) {
6624 		verbose(env,
6625 			"R%d doesn't have constant offset. kptr has to be at the constant offset\n",
6626 			regno);
6627 		return -EINVAL;
6628 	}
6629 	if (!map_ptr->btf) {
6630 		verbose(env, "map '%s' has to have BTF in order to use bpf_kptr_xchg\n",
6631 			map_ptr->name);
6632 		return -EINVAL;
6633 	}
6634 	if (!btf_record_has_field(map_ptr->record, BPF_KPTR)) {
6635 		verbose(env, "map '%s' has no valid kptr\n", map_ptr->name);
6636 		return -EINVAL;
6637 	}
6638 
6639 	meta->map_ptr = map_ptr;
6640 	kptr_off = reg->off + reg->var_off.value;
6641 	kptr_field = btf_record_find(map_ptr->record, kptr_off, BPF_KPTR);
6642 	if (!kptr_field) {
6643 		verbose(env, "off=%d doesn't point to kptr\n", kptr_off);
6644 		return -EACCES;
6645 	}
6646 	if (kptr_field->type != BPF_KPTR_REF) {
6647 		verbose(env, "off=%d kptr isn't referenced kptr\n", kptr_off);
6648 		return -EACCES;
6649 	}
6650 	meta->kptr_field = kptr_field;
6651 	return 0;
6652 }
6653 
6654 /* There are two register types representing a bpf_dynptr, one is PTR_TO_STACK
6655  * which points to a stack slot, and the other is CONST_PTR_TO_DYNPTR.
6656  *
6657  * In both cases we deal with the first 8 bytes, but need to mark the next 8
6658  * bytes as STACK_DYNPTR in case of PTR_TO_STACK. In case of
6659  * CONST_PTR_TO_DYNPTR, we are guaranteed to get the beginning of the object.
6660  *
6661  * Mutability of bpf_dynptr is at two levels, one is at the level of struct
6662  * bpf_dynptr itself, i.e. whether the helper is receiving a pointer to struct
6663  * bpf_dynptr or pointer to const struct bpf_dynptr. In the former case, it can
6664  * mutate the view of the dynptr and also possibly destroy it. In the latter
6665  * case, it cannot mutate the bpf_dynptr itself but it can still mutate the
6666  * memory that dynptr points to.
6667  *
6668  * The verifier will keep track both levels of mutation (bpf_dynptr's in
6669  * reg->type and the memory's in reg->dynptr.type), but there is no support for
6670  * readonly dynptr view yet, hence only the first case is tracked and checked.
6671  *
6672  * This is consistent with how C applies the const modifier to a struct object,
6673  * where the pointer itself inside bpf_dynptr becomes const but not what it
6674  * points to.
6675  *
6676  * Helpers which do not mutate the bpf_dynptr set MEM_RDONLY in their argument
6677  * type, and declare it as 'const struct bpf_dynptr *' in their prototype.
6678  */
6679 static int process_dynptr_func(struct bpf_verifier_env *env, int regno, int insn_idx,
6680 			       enum bpf_arg_type arg_type)
6681 {
6682 	struct bpf_reg_state *regs = cur_regs(env), *reg = &regs[regno];
6683 	int err;
6684 
6685 	/* MEM_UNINIT and MEM_RDONLY are exclusive, when applied to an
6686 	 * ARG_PTR_TO_DYNPTR (or ARG_PTR_TO_DYNPTR | DYNPTR_TYPE_*):
6687 	 */
6688 	if ((arg_type & (MEM_UNINIT | MEM_RDONLY)) == (MEM_UNINIT | MEM_RDONLY)) {
6689 		verbose(env, "verifier internal error: misconfigured dynptr helper type flags\n");
6690 		return -EFAULT;
6691 	}
6692 
6693 	/*  MEM_UNINIT - Points to memory that is an appropriate candidate for
6694 	 *		 constructing a mutable bpf_dynptr object.
6695 	 *
6696 	 *		 Currently, this is only possible with PTR_TO_STACK
6697 	 *		 pointing to a region of at least 16 bytes which doesn't
6698 	 *		 contain an existing bpf_dynptr.
6699 	 *
6700 	 *  MEM_RDONLY - Points to a initialized bpf_dynptr that will not be
6701 	 *		 mutated or destroyed. However, the memory it points to
6702 	 *		 may be mutated.
6703 	 *
6704 	 *  None       - Points to a initialized dynptr that can be mutated and
6705 	 *		 destroyed, including mutation of the memory it points
6706 	 *		 to.
6707 	 */
6708 	if (arg_type & MEM_UNINIT) {
6709 		int i;
6710 
6711 		if (!is_dynptr_reg_valid_uninit(env, reg)) {
6712 			verbose(env, "Dynptr has to be an uninitialized dynptr\n");
6713 			return -EINVAL;
6714 		}
6715 
6716 		/* we write BPF_DW bits (8 bytes) at a time */
6717 		for (i = 0; i < BPF_DYNPTR_SIZE; i += 8) {
6718 			err = check_mem_access(env, insn_idx, regno,
6719 					       i, BPF_DW, BPF_WRITE, -1, false);
6720 			if (err)
6721 				return err;
6722 		}
6723 
6724 		err = mark_stack_slots_dynptr(env, reg, arg_type, insn_idx);
6725 	} else /* MEM_RDONLY and None case from above */ {
6726 		/* For the reg->type == PTR_TO_STACK case, bpf_dynptr is never const */
6727 		if (reg->type == CONST_PTR_TO_DYNPTR && !(arg_type & MEM_RDONLY)) {
6728 			verbose(env, "cannot pass pointer to const bpf_dynptr, the helper mutates it\n");
6729 			return -EINVAL;
6730 		}
6731 
6732 		if (!is_dynptr_reg_valid_init(env, reg)) {
6733 			verbose(env,
6734 				"Expected an initialized dynptr as arg #%d\n",
6735 				regno);
6736 			return -EINVAL;
6737 		}
6738 
6739 		/* Fold modifiers (in this case, MEM_RDONLY) when checking expected type */
6740 		if (!is_dynptr_type_expected(env, reg, arg_type & ~MEM_RDONLY)) {
6741 			verbose(env,
6742 				"Expected a dynptr of type %s as arg #%d\n",
6743 				dynptr_type_str(arg_to_dynptr_type(arg_type)), regno);
6744 			return -EINVAL;
6745 		}
6746 
6747 		err = mark_dynptr_read(env, reg);
6748 	}
6749 	return err;
6750 }
6751 
6752 static u32 iter_ref_obj_id(struct bpf_verifier_env *env, struct bpf_reg_state *reg, int spi)
6753 {
6754 	struct bpf_func_state *state = func(env, reg);
6755 
6756 	return state->stack[spi].spilled_ptr.ref_obj_id;
6757 }
6758 
6759 static bool is_iter_kfunc(struct bpf_kfunc_call_arg_meta *meta)
6760 {
6761 	return meta->kfunc_flags & (KF_ITER_NEW | KF_ITER_NEXT | KF_ITER_DESTROY);
6762 }
6763 
6764 static bool is_iter_new_kfunc(struct bpf_kfunc_call_arg_meta *meta)
6765 {
6766 	return meta->kfunc_flags & KF_ITER_NEW;
6767 }
6768 
6769 static bool is_iter_next_kfunc(struct bpf_kfunc_call_arg_meta *meta)
6770 {
6771 	return meta->kfunc_flags & KF_ITER_NEXT;
6772 }
6773 
6774 static bool is_iter_destroy_kfunc(struct bpf_kfunc_call_arg_meta *meta)
6775 {
6776 	return meta->kfunc_flags & KF_ITER_DESTROY;
6777 }
6778 
6779 static bool is_kfunc_arg_iter(struct bpf_kfunc_call_arg_meta *meta, int arg)
6780 {
6781 	/* btf_check_iter_kfuncs() guarantees that first argument of any iter
6782 	 * kfunc is iter state pointer
6783 	 */
6784 	return arg == 0 && is_iter_kfunc(meta);
6785 }
6786 
6787 static int process_iter_arg(struct bpf_verifier_env *env, int regno, int insn_idx,
6788 			    struct bpf_kfunc_call_arg_meta *meta)
6789 {
6790 	struct bpf_reg_state *regs = cur_regs(env), *reg = &regs[regno];
6791 	const struct btf_type *t;
6792 	const struct btf_param *arg;
6793 	int spi, err, i, nr_slots;
6794 	u32 btf_id;
6795 
6796 	/* btf_check_iter_kfuncs() ensures we don't need to validate anything here */
6797 	arg = &btf_params(meta->func_proto)[0];
6798 	t = btf_type_skip_modifiers(meta->btf, arg->type, NULL);	/* PTR */
6799 	t = btf_type_skip_modifiers(meta->btf, t->type, &btf_id);	/* STRUCT */
6800 	nr_slots = t->size / BPF_REG_SIZE;
6801 
6802 	if (is_iter_new_kfunc(meta)) {
6803 		/* bpf_iter_<type>_new() expects pointer to uninit iter state */
6804 		if (!is_iter_reg_valid_uninit(env, reg, nr_slots)) {
6805 			verbose(env, "expected uninitialized iter_%s as arg #%d\n",
6806 				iter_type_str(meta->btf, btf_id), regno);
6807 			return -EINVAL;
6808 		}
6809 
6810 		for (i = 0; i < nr_slots * 8; i += BPF_REG_SIZE) {
6811 			err = check_mem_access(env, insn_idx, regno,
6812 					       i, BPF_DW, BPF_WRITE, -1, false);
6813 			if (err)
6814 				return err;
6815 		}
6816 
6817 		err = mark_stack_slots_iter(env, reg, insn_idx, meta->btf, btf_id, nr_slots);
6818 		if (err)
6819 			return err;
6820 	} else {
6821 		/* iter_next() or iter_destroy() expect initialized iter state*/
6822 		if (!is_iter_reg_valid_init(env, reg, meta->btf, btf_id, nr_slots)) {
6823 			verbose(env, "expected an initialized iter_%s as arg #%d\n",
6824 				iter_type_str(meta->btf, btf_id), regno);
6825 			return -EINVAL;
6826 		}
6827 
6828 		spi = iter_get_spi(env, reg, nr_slots);
6829 		if (spi < 0)
6830 			return spi;
6831 
6832 		err = mark_iter_read(env, reg, spi, nr_slots);
6833 		if (err)
6834 			return err;
6835 
6836 		/* remember meta->iter info for process_iter_next_call() */
6837 		meta->iter.spi = spi;
6838 		meta->iter.frameno = reg->frameno;
6839 		meta->ref_obj_id = iter_ref_obj_id(env, reg, spi);
6840 
6841 		if (is_iter_destroy_kfunc(meta)) {
6842 			err = unmark_stack_slots_iter(env, reg, nr_slots);
6843 			if (err)
6844 				return err;
6845 		}
6846 	}
6847 
6848 	return 0;
6849 }
6850 
6851 /* process_iter_next_call() is called when verifier gets to iterator's next
6852  * "method" (e.g., bpf_iter_num_next() for numbers iterator) call. We'll refer
6853  * to it as just "iter_next()" in comments below.
6854  *
6855  * BPF verifier relies on a crucial contract for any iter_next()
6856  * implementation: it should *eventually* return NULL, and once that happens
6857  * it should keep returning NULL. That is, once iterator exhausts elements to
6858  * iterate, it should never reset or spuriously return new elements.
6859  *
6860  * With the assumption of such contract, process_iter_next_call() simulates
6861  * a fork in the verifier state to validate loop logic correctness and safety
6862  * without having to simulate infinite amount of iterations.
6863  *
6864  * In current state, we first assume that iter_next() returned NULL and
6865  * iterator state is set to DRAINED (BPF_ITER_STATE_DRAINED). In such
6866  * conditions we should not form an infinite loop and should eventually reach
6867  * exit.
6868  *
6869  * Besides that, we also fork current state and enqueue it for later
6870  * verification. In a forked state we keep iterator state as ACTIVE
6871  * (BPF_ITER_STATE_ACTIVE) and assume non-NULL return from iter_next(). We
6872  * also bump iteration depth to prevent erroneous infinite loop detection
6873  * later on (see iter_active_depths_differ() comment for details). In this
6874  * state we assume that we'll eventually loop back to another iter_next()
6875  * calls (it could be in exactly same location or in some other instruction,
6876  * it doesn't matter, we don't make any unnecessary assumptions about this,
6877  * everything revolves around iterator state in a stack slot, not which
6878  * instruction is calling iter_next()). When that happens, we either will come
6879  * to iter_next() with equivalent state and can conclude that next iteration
6880  * will proceed in exactly the same way as we just verified, so it's safe to
6881  * assume that loop converges. If not, we'll go on another iteration
6882  * simulation with a different input state, until all possible starting states
6883  * are validated or we reach maximum number of instructions limit.
6884  *
6885  * This way, we will either exhaustively discover all possible input states
6886  * that iterator loop can start with and eventually will converge, or we'll
6887  * effectively regress into bounded loop simulation logic and either reach
6888  * maximum number of instructions if loop is not provably convergent, or there
6889  * is some statically known limit on number of iterations (e.g., if there is
6890  * an explicit `if n > 100 then break;` statement somewhere in the loop).
6891  *
6892  * One very subtle but very important aspect is that we *always* simulate NULL
6893  * condition first (as the current state) before we simulate non-NULL case.
6894  * This has to do with intricacies of scalar precision tracking. By simulating
6895  * "exit condition" of iter_next() returning NULL first, we make sure all the
6896  * relevant precision marks *that will be set **after** we exit iterator loop*
6897  * are propagated backwards to common parent state of NULL and non-NULL
6898  * branches. Thanks to that, state equivalence checks done later in forked
6899  * state, when reaching iter_next() for ACTIVE iterator, can assume that
6900  * precision marks are finalized and won't change. Because simulating another
6901  * ACTIVE iterator iteration won't change them (because given same input
6902  * states we'll end up with exactly same output states which we are currently
6903  * comparing; and verification after the loop already propagated back what
6904  * needs to be **additionally** tracked as precise). It's subtle, grok
6905  * precision tracking for more intuitive understanding.
6906  */
6907 static int process_iter_next_call(struct bpf_verifier_env *env, int insn_idx,
6908 				  struct bpf_kfunc_call_arg_meta *meta)
6909 {
6910 	struct bpf_verifier_state *cur_st = env->cur_state, *queued_st;
6911 	struct bpf_func_state *cur_fr = cur_st->frame[cur_st->curframe], *queued_fr;
6912 	struct bpf_reg_state *cur_iter, *queued_iter;
6913 	int iter_frameno = meta->iter.frameno;
6914 	int iter_spi = meta->iter.spi;
6915 
6916 	BTF_TYPE_EMIT(struct bpf_iter);
6917 
6918 	cur_iter = &env->cur_state->frame[iter_frameno]->stack[iter_spi].spilled_ptr;
6919 
6920 	if (cur_iter->iter.state != BPF_ITER_STATE_ACTIVE &&
6921 	    cur_iter->iter.state != BPF_ITER_STATE_DRAINED) {
6922 		verbose(env, "verifier internal error: unexpected iterator state %d (%s)\n",
6923 			cur_iter->iter.state, iter_state_str(cur_iter->iter.state));
6924 		return -EFAULT;
6925 	}
6926 
6927 	if (cur_iter->iter.state == BPF_ITER_STATE_ACTIVE) {
6928 		/* branch out active iter state */
6929 		queued_st = push_stack(env, insn_idx + 1, insn_idx, false);
6930 		if (!queued_st)
6931 			return -ENOMEM;
6932 
6933 		queued_iter = &queued_st->frame[iter_frameno]->stack[iter_spi].spilled_ptr;
6934 		queued_iter->iter.state = BPF_ITER_STATE_ACTIVE;
6935 		queued_iter->iter.depth++;
6936 
6937 		queued_fr = queued_st->frame[queued_st->curframe];
6938 		mark_ptr_not_null_reg(&queued_fr->regs[BPF_REG_0]);
6939 	}
6940 
6941 	/* switch to DRAINED state, but keep the depth unchanged */
6942 	/* mark current iter state as drained and assume returned NULL */
6943 	cur_iter->iter.state = BPF_ITER_STATE_DRAINED;
6944 	__mark_reg_const_zero(&cur_fr->regs[BPF_REG_0]);
6945 
6946 	return 0;
6947 }
6948 
6949 static bool arg_type_is_mem_size(enum bpf_arg_type type)
6950 {
6951 	return type == ARG_CONST_SIZE ||
6952 	       type == ARG_CONST_SIZE_OR_ZERO;
6953 }
6954 
6955 static bool arg_type_is_release(enum bpf_arg_type type)
6956 {
6957 	return type & OBJ_RELEASE;
6958 }
6959 
6960 static bool arg_type_is_dynptr(enum bpf_arg_type type)
6961 {
6962 	return base_type(type) == ARG_PTR_TO_DYNPTR;
6963 }
6964 
6965 static int int_ptr_type_to_size(enum bpf_arg_type type)
6966 {
6967 	if (type == ARG_PTR_TO_INT)
6968 		return sizeof(u32);
6969 	else if (type == ARG_PTR_TO_LONG)
6970 		return sizeof(u64);
6971 
6972 	return -EINVAL;
6973 }
6974 
6975 static int resolve_map_arg_type(struct bpf_verifier_env *env,
6976 				 const struct bpf_call_arg_meta *meta,
6977 				 enum bpf_arg_type *arg_type)
6978 {
6979 	if (!meta->map_ptr) {
6980 		/* kernel subsystem misconfigured verifier */
6981 		verbose(env, "invalid map_ptr to access map->type\n");
6982 		return -EACCES;
6983 	}
6984 
6985 	switch (meta->map_ptr->map_type) {
6986 	case BPF_MAP_TYPE_SOCKMAP:
6987 	case BPF_MAP_TYPE_SOCKHASH:
6988 		if (*arg_type == ARG_PTR_TO_MAP_VALUE) {
6989 			*arg_type = ARG_PTR_TO_BTF_ID_SOCK_COMMON;
6990 		} else {
6991 			verbose(env, "invalid arg_type for sockmap/sockhash\n");
6992 			return -EINVAL;
6993 		}
6994 		break;
6995 	case BPF_MAP_TYPE_BLOOM_FILTER:
6996 		if (meta->func_id == BPF_FUNC_map_peek_elem)
6997 			*arg_type = ARG_PTR_TO_MAP_VALUE;
6998 		break;
6999 	default:
7000 		break;
7001 	}
7002 	return 0;
7003 }
7004 
7005 struct bpf_reg_types {
7006 	const enum bpf_reg_type types[10];
7007 	u32 *btf_id;
7008 };
7009 
7010 static const struct bpf_reg_types sock_types = {
7011 	.types = {
7012 		PTR_TO_SOCK_COMMON,
7013 		PTR_TO_SOCKET,
7014 		PTR_TO_TCP_SOCK,
7015 		PTR_TO_XDP_SOCK,
7016 	},
7017 };
7018 
7019 #ifdef CONFIG_NET
7020 static const struct bpf_reg_types btf_id_sock_common_types = {
7021 	.types = {
7022 		PTR_TO_SOCK_COMMON,
7023 		PTR_TO_SOCKET,
7024 		PTR_TO_TCP_SOCK,
7025 		PTR_TO_XDP_SOCK,
7026 		PTR_TO_BTF_ID,
7027 		PTR_TO_BTF_ID | PTR_TRUSTED,
7028 	},
7029 	.btf_id = &btf_sock_ids[BTF_SOCK_TYPE_SOCK_COMMON],
7030 };
7031 #endif
7032 
7033 static const struct bpf_reg_types mem_types = {
7034 	.types = {
7035 		PTR_TO_STACK,
7036 		PTR_TO_PACKET,
7037 		PTR_TO_PACKET_META,
7038 		PTR_TO_MAP_KEY,
7039 		PTR_TO_MAP_VALUE,
7040 		PTR_TO_MEM,
7041 		PTR_TO_MEM | MEM_RINGBUF,
7042 		PTR_TO_BUF,
7043 		PTR_TO_BTF_ID | PTR_TRUSTED,
7044 	},
7045 };
7046 
7047 static const struct bpf_reg_types int_ptr_types = {
7048 	.types = {
7049 		PTR_TO_STACK,
7050 		PTR_TO_PACKET,
7051 		PTR_TO_PACKET_META,
7052 		PTR_TO_MAP_KEY,
7053 		PTR_TO_MAP_VALUE,
7054 	},
7055 };
7056 
7057 static const struct bpf_reg_types spin_lock_types = {
7058 	.types = {
7059 		PTR_TO_MAP_VALUE,
7060 		PTR_TO_BTF_ID | MEM_ALLOC,
7061 	}
7062 };
7063 
7064 static const struct bpf_reg_types fullsock_types = { .types = { PTR_TO_SOCKET } };
7065 static const struct bpf_reg_types scalar_types = { .types = { SCALAR_VALUE } };
7066 static const struct bpf_reg_types context_types = { .types = { PTR_TO_CTX } };
7067 static const struct bpf_reg_types ringbuf_mem_types = { .types = { PTR_TO_MEM | MEM_RINGBUF } };
7068 static const struct bpf_reg_types const_map_ptr_types = { .types = { CONST_PTR_TO_MAP } };
7069 static const struct bpf_reg_types btf_ptr_types = {
7070 	.types = {
7071 		PTR_TO_BTF_ID,
7072 		PTR_TO_BTF_ID | PTR_TRUSTED,
7073 		PTR_TO_BTF_ID | MEM_RCU,
7074 	},
7075 };
7076 static const struct bpf_reg_types percpu_btf_ptr_types = {
7077 	.types = {
7078 		PTR_TO_BTF_ID | MEM_PERCPU,
7079 		PTR_TO_BTF_ID | MEM_PERCPU | PTR_TRUSTED,
7080 	}
7081 };
7082 static const struct bpf_reg_types func_ptr_types = { .types = { PTR_TO_FUNC } };
7083 static const struct bpf_reg_types stack_ptr_types = { .types = { PTR_TO_STACK } };
7084 static const struct bpf_reg_types const_str_ptr_types = { .types = { PTR_TO_MAP_VALUE } };
7085 static const struct bpf_reg_types timer_types = { .types = { PTR_TO_MAP_VALUE } };
7086 static const struct bpf_reg_types kptr_types = { .types = { PTR_TO_MAP_VALUE } };
7087 static const struct bpf_reg_types dynptr_types = {
7088 	.types = {
7089 		PTR_TO_STACK,
7090 		CONST_PTR_TO_DYNPTR,
7091 	}
7092 };
7093 
7094 static const struct bpf_reg_types *compatible_reg_types[__BPF_ARG_TYPE_MAX] = {
7095 	[ARG_PTR_TO_MAP_KEY]		= &mem_types,
7096 	[ARG_PTR_TO_MAP_VALUE]		= &mem_types,
7097 	[ARG_CONST_SIZE]		= &scalar_types,
7098 	[ARG_CONST_SIZE_OR_ZERO]	= &scalar_types,
7099 	[ARG_CONST_ALLOC_SIZE_OR_ZERO]	= &scalar_types,
7100 	[ARG_CONST_MAP_PTR]		= &const_map_ptr_types,
7101 	[ARG_PTR_TO_CTX]		= &context_types,
7102 	[ARG_PTR_TO_SOCK_COMMON]	= &sock_types,
7103 #ifdef CONFIG_NET
7104 	[ARG_PTR_TO_BTF_ID_SOCK_COMMON]	= &btf_id_sock_common_types,
7105 #endif
7106 	[ARG_PTR_TO_SOCKET]		= &fullsock_types,
7107 	[ARG_PTR_TO_BTF_ID]		= &btf_ptr_types,
7108 	[ARG_PTR_TO_SPIN_LOCK]		= &spin_lock_types,
7109 	[ARG_PTR_TO_MEM]		= &mem_types,
7110 	[ARG_PTR_TO_RINGBUF_MEM]	= &ringbuf_mem_types,
7111 	[ARG_PTR_TO_INT]		= &int_ptr_types,
7112 	[ARG_PTR_TO_LONG]		= &int_ptr_types,
7113 	[ARG_PTR_TO_PERCPU_BTF_ID]	= &percpu_btf_ptr_types,
7114 	[ARG_PTR_TO_FUNC]		= &func_ptr_types,
7115 	[ARG_PTR_TO_STACK]		= &stack_ptr_types,
7116 	[ARG_PTR_TO_CONST_STR]		= &const_str_ptr_types,
7117 	[ARG_PTR_TO_TIMER]		= &timer_types,
7118 	[ARG_PTR_TO_KPTR]		= &kptr_types,
7119 	[ARG_PTR_TO_DYNPTR]		= &dynptr_types,
7120 };
7121 
7122 static int check_reg_type(struct bpf_verifier_env *env, u32 regno,
7123 			  enum bpf_arg_type arg_type,
7124 			  const u32 *arg_btf_id,
7125 			  struct bpf_call_arg_meta *meta)
7126 {
7127 	struct bpf_reg_state *regs = cur_regs(env), *reg = &regs[regno];
7128 	enum bpf_reg_type expected, type = reg->type;
7129 	const struct bpf_reg_types *compatible;
7130 	int i, j;
7131 
7132 	compatible = compatible_reg_types[base_type(arg_type)];
7133 	if (!compatible) {
7134 		verbose(env, "verifier internal error: unsupported arg type %d\n", arg_type);
7135 		return -EFAULT;
7136 	}
7137 
7138 	/* ARG_PTR_TO_MEM + RDONLY is compatible with PTR_TO_MEM and PTR_TO_MEM + RDONLY,
7139 	 * but ARG_PTR_TO_MEM is compatible only with PTR_TO_MEM and NOT with PTR_TO_MEM + RDONLY
7140 	 *
7141 	 * Same for MAYBE_NULL:
7142 	 *
7143 	 * ARG_PTR_TO_MEM + MAYBE_NULL is compatible with PTR_TO_MEM and PTR_TO_MEM + MAYBE_NULL,
7144 	 * but ARG_PTR_TO_MEM is compatible only with PTR_TO_MEM but NOT with PTR_TO_MEM + MAYBE_NULL
7145 	 *
7146 	 * Therefore we fold these flags depending on the arg_type before comparison.
7147 	 */
7148 	if (arg_type & MEM_RDONLY)
7149 		type &= ~MEM_RDONLY;
7150 	if (arg_type & PTR_MAYBE_NULL)
7151 		type &= ~PTR_MAYBE_NULL;
7152 
7153 	if (meta->func_id == BPF_FUNC_kptr_xchg && type & MEM_ALLOC)
7154 		type &= ~MEM_ALLOC;
7155 
7156 	for (i = 0; i < ARRAY_SIZE(compatible->types); i++) {
7157 		expected = compatible->types[i];
7158 		if (expected == NOT_INIT)
7159 			break;
7160 
7161 		if (type == expected)
7162 			goto found;
7163 	}
7164 
7165 	verbose(env, "R%d type=%s expected=", regno, reg_type_str(env, reg->type));
7166 	for (j = 0; j + 1 < i; j++)
7167 		verbose(env, "%s, ", reg_type_str(env, compatible->types[j]));
7168 	verbose(env, "%s\n", reg_type_str(env, compatible->types[j]));
7169 	return -EACCES;
7170 
7171 found:
7172 	if (base_type(reg->type) != PTR_TO_BTF_ID)
7173 		return 0;
7174 
7175 	if (compatible == &mem_types) {
7176 		if (!(arg_type & MEM_RDONLY)) {
7177 			verbose(env,
7178 				"%s() may write into memory pointed by R%d type=%s\n",
7179 				func_id_name(meta->func_id),
7180 				regno, reg_type_str(env, reg->type));
7181 			return -EACCES;
7182 		}
7183 		return 0;
7184 	}
7185 
7186 	switch ((int)reg->type) {
7187 	case PTR_TO_BTF_ID:
7188 	case PTR_TO_BTF_ID | PTR_TRUSTED:
7189 	case PTR_TO_BTF_ID | MEM_RCU:
7190 	case PTR_TO_BTF_ID | PTR_MAYBE_NULL:
7191 	case PTR_TO_BTF_ID | PTR_MAYBE_NULL | MEM_RCU:
7192 	{
7193 		/* For bpf_sk_release, it needs to match against first member
7194 		 * 'struct sock_common', hence make an exception for it. This
7195 		 * allows bpf_sk_release to work for multiple socket types.
7196 		 */
7197 		bool strict_type_match = arg_type_is_release(arg_type) &&
7198 					 meta->func_id != BPF_FUNC_sk_release;
7199 
7200 		if (type_may_be_null(reg->type) &&
7201 		    (!type_may_be_null(arg_type) || arg_type_is_release(arg_type))) {
7202 			verbose(env, "Possibly NULL pointer passed to helper arg%d\n", regno);
7203 			return -EACCES;
7204 		}
7205 
7206 		if (!arg_btf_id) {
7207 			if (!compatible->btf_id) {
7208 				verbose(env, "verifier internal error: missing arg compatible BTF ID\n");
7209 				return -EFAULT;
7210 			}
7211 			arg_btf_id = compatible->btf_id;
7212 		}
7213 
7214 		if (meta->func_id == BPF_FUNC_kptr_xchg) {
7215 			if (map_kptr_match_type(env, meta->kptr_field, reg, regno))
7216 				return -EACCES;
7217 		} else {
7218 			if (arg_btf_id == BPF_PTR_POISON) {
7219 				verbose(env, "verifier internal error:");
7220 				verbose(env, "R%d has non-overwritten BPF_PTR_POISON type\n",
7221 					regno);
7222 				return -EACCES;
7223 			}
7224 
7225 			if (!btf_struct_ids_match(&env->log, reg->btf, reg->btf_id, reg->off,
7226 						  btf_vmlinux, *arg_btf_id,
7227 						  strict_type_match)) {
7228 				verbose(env, "R%d is of type %s but %s is expected\n",
7229 					regno, btf_type_name(reg->btf, reg->btf_id),
7230 					btf_type_name(btf_vmlinux, *arg_btf_id));
7231 				return -EACCES;
7232 			}
7233 		}
7234 		break;
7235 	}
7236 	case PTR_TO_BTF_ID | MEM_ALLOC:
7237 		if (meta->func_id != BPF_FUNC_spin_lock && meta->func_id != BPF_FUNC_spin_unlock &&
7238 		    meta->func_id != BPF_FUNC_kptr_xchg) {
7239 			verbose(env, "verifier internal error: unimplemented handling of MEM_ALLOC\n");
7240 			return -EFAULT;
7241 		}
7242 		/* Handled by helper specific checks */
7243 		break;
7244 	case PTR_TO_BTF_ID | MEM_PERCPU:
7245 	case PTR_TO_BTF_ID | MEM_PERCPU | PTR_TRUSTED:
7246 		/* Handled by helper specific checks */
7247 		break;
7248 	default:
7249 		verbose(env, "verifier internal error: invalid PTR_TO_BTF_ID register for type match\n");
7250 		return -EFAULT;
7251 	}
7252 	return 0;
7253 }
7254 
7255 static struct btf_field *
7256 reg_find_field_offset(const struct bpf_reg_state *reg, s32 off, u32 fields)
7257 {
7258 	struct btf_field *field;
7259 	struct btf_record *rec;
7260 
7261 	rec = reg_btf_record(reg);
7262 	if (!rec)
7263 		return NULL;
7264 
7265 	field = btf_record_find(rec, off, fields);
7266 	if (!field)
7267 		return NULL;
7268 
7269 	return field;
7270 }
7271 
7272 int check_func_arg_reg_off(struct bpf_verifier_env *env,
7273 			   const struct bpf_reg_state *reg, int regno,
7274 			   enum bpf_arg_type arg_type)
7275 {
7276 	u32 type = reg->type;
7277 
7278 	/* When referenced register is passed to release function, its fixed
7279 	 * offset must be 0.
7280 	 *
7281 	 * We will check arg_type_is_release reg has ref_obj_id when storing
7282 	 * meta->release_regno.
7283 	 */
7284 	if (arg_type_is_release(arg_type)) {
7285 		/* ARG_PTR_TO_DYNPTR with OBJ_RELEASE is a bit special, as it
7286 		 * may not directly point to the object being released, but to
7287 		 * dynptr pointing to such object, which might be at some offset
7288 		 * on the stack. In that case, we simply to fallback to the
7289 		 * default handling.
7290 		 */
7291 		if (arg_type_is_dynptr(arg_type) && type == PTR_TO_STACK)
7292 			return 0;
7293 
7294 		if ((type_is_ptr_alloc_obj(type) || type_is_non_owning_ref(type)) && reg->off) {
7295 			if (reg_find_field_offset(reg, reg->off, BPF_GRAPH_NODE_OR_ROOT))
7296 				return __check_ptr_off_reg(env, reg, regno, true);
7297 
7298 			verbose(env, "R%d must have zero offset when passed to release func\n",
7299 				regno);
7300 			verbose(env, "No graph node or root found at R%d type:%s off:%d\n", regno,
7301 				btf_type_name(reg->btf, reg->btf_id), reg->off);
7302 			return -EINVAL;
7303 		}
7304 
7305 		/* Doing check_ptr_off_reg check for the offset will catch this
7306 		 * because fixed_off_ok is false, but checking here allows us
7307 		 * to give the user a better error message.
7308 		 */
7309 		if (reg->off) {
7310 			verbose(env, "R%d must have zero offset when passed to release func or trusted arg to kfunc\n",
7311 				regno);
7312 			return -EINVAL;
7313 		}
7314 		return __check_ptr_off_reg(env, reg, regno, false);
7315 	}
7316 
7317 	switch (type) {
7318 	/* Pointer types where both fixed and variable offset is explicitly allowed: */
7319 	case PTR_TO_STACK:
7320 	case PTR_TO_PACKET:
7321 	case PTR_TO_PACKET_META:
7322 	case PTR_TO_MAP_KEY:
7323 	case PTR_TO_MAP_VALUE:
7324 	case PTR_TO_MEM:
7325 	case PTR_TO_MEM | MEM_RDONLY:
7326 	case PTR_TO_MEM | MEM_RINGBUF:
7327 	case PTR_TO_BUF:
7328 	case PTR_TO_BUF | MEM_RDONLY:
7329 	case SCALAR_VALUE:
7330 		return 0;
7331 	/* All the rest must be rejected, except PTR_TO_BTF_ID which allows
7332 	 * fixed offset.
7333 	 */
7334 	case PTR_TO_BTF_ID:
7335 	case PTR_TO_BTF_ID | MEM_ALLOC:
7336 	case PTR_TO_BTF_ID | PTR_TRUSTED:
7337 	case PTR_TO_BTF_ID | MEM_RCU:
7338 	case PTR_TO_BTF_ID | MEM_ALLOC | NON_OWN_REF:
7339 		/* When referenced PTR_TO_BTF_ID is passed to release function,
7340 		 * its fixed offset must be 0. In the other cases, fixed offset
7341 		 * can be non-zero. This was already checked above. So pass
7342 		 * fixed_off_ok as true to allow fixed offset for all other
7343 		 * cases. var_off always must be 0 for PTR_TO_BTF_ID, hence we
7344 		 * still need to do checks instead of returning.
7345 		 */
7346 		return __check_ptr_off_reg(env, reg, regno, true);
7347 	default:
7348 		return __check_ptr_off_reg(env, reg, regno, false);
7349 	}
7350 }
7351 
7352 static struct bpf_reg_state *get_dynptr_arg_reg(struct bpf_verifier_env *env,
7353 						const struct bpf_func_proto *fn,
7354 						struct bpf_reg_state *regs)
7355 {
7356 	struct bpf_reg_state *state = NULL;
7357 	int i;
7358 
7359 	for (i = 0; i < MAX_BPF_FUNC_REG_ARGS; i++)
7360 		if (arg_type_is_dynptr(fn->arg_type[i])) {
7361 			if (state) {
7362 				verbose(env, "verifier internal error: multiple dynptr args\n");
7363 				return NULL;
7364 			}
7365 			state = &regs[BPF_REG_1 + i];
7366 		}
7367 
7368 	if (!state)
7369 		verbose(env, "verifier internal error: no dynptr arg found\n");
7370 
7371 	return state;
7372 }
7373 
7374 static int dynptr_id(struct bpf_verifier_env *env, struct bpf_reg_state *reg)
7375 {
7376 	struct bpf_func_state *state = func(env, reg);
7377 	int spi;
7378 
7379 	if (reg->type == CONST_PTR_TO_DYNPTR)
7380 		return reg->id;
7381 	spi = dynptr_get_spi(env, reg);
7382 	if (spi < 0)
7383 		return spi;
7384 	return state->stack[spi].spilled_ptr.id;
7385 }
7386 
7387 static int dynptr_ref_obj_id(struct bpf_verifier_env *env, struct bpf_reg_state *reg)
7388 {
7389 	struct bpf_func_state *state = func(env, reg);
7390 	int spi;
7391 
7392 	if (reg->type == CONST_PTR_TO_DYNPTR)
7393 		return reg->ref_obj_id;
7394 	spi = dynptr_get_spi(env, reg);
7395 	if (spi < 0)
7396 		return spi;
7397 	return state->stack[spi].spilled_ptr.ref_obj_id;
7398 }
7399 
7400 static enum bpf_dynptr_type dynptr_get_type(struct bpf_verifier_env *env,
7401 					    struct bpf_reg_state *reg)
7402 {
7403 	struct bpf_func_state *state = func(env, reg);
7404 	int spi;
7405 
7406 	if (reg->type == CONST_PTR_TO_DYNPTR)
7407 		return reg->dynptr.type;
7408 
7409 	spi = __get_spi(reg->off);
7410 	if (spi < 0) {
7411 		verbose(env, "verifier internal error: invalid spi when querying dynptr type\n");
7412 		return BPF_DYNPTR_TYPE_INVALID;
7413 	}
7414 
7415 	return state->stack[spi].spilled_ptr.dynptr.type;
7416 }
7417 
7418 static int check_func_arg(struct bpf_verifier_env *env, u32 arg,
7419 			  struct bpf_call_arg_meta *meta,
7420 			  const struct bpf_func_proto *fn,
7421 			  int insn_idx)
7422 {
7423 	u32 regno = BPF_REG_1 + arg;
7424 	struct bpf_reg_state *regs = cur_regs(env), *reg = &regs[regno];
7425 	enum bpf_arg_type arg_type = fn->arg_type[arg];
7426 	enum bpf_reg_type type = reg->type;
7427 	u32 *arg_btf_id = NULL;
7428 	int err = 0;
7429 
7430 	if (arg_type == ARG_DONTCARE)
7431 		return 0;
7432 
7433 	err = check_reg_arg(env, regno, SRC_OP);
7434 	if (err)
7435 		return err;
7436 
7437 	if (arg_type == ARG_ANYTHING) {
7438 		if (is_pointer_value(env, regno)) {
7439 			verbose(env, "R%d leaks addr into helper function\n",
7440 				regno);
7441 			return -EACCES;
7442 		}
7443 		return 0;
7444 	}
7445 
7446 	if (type_is_pkt_pointer(type) &&
7447 	    !may_access_direct_pkt_data(env, meta, BPF_READ)) {
7448 		verbose(env, "helper access to the packet is not allowed\n");
7449 		return -EACCES;
7450 	}
7451 
7452 	if (base_type(arg_type) == ARG_PTR_TO_MAP_VALUE) {
7453 		err = resolve_map_arg_type(env, meta, &arg_type);
7454 		if (err)
7455 			return err;
7456 	}
7457 
7458 	if (register_is_null(reg) && type_may_be_null(arg_type))
7459 		/* A NULL register has a SCALAR_VALUE type, so skip
7460 		 * type checking.
7461 		 */
7462 		goto skip_type_check;
7463 
7464 	/* arg_btf_id and arg_size are in a union. */
7465 	if (base_type(arg_type) == ARG_PTR_TO_BTF_ID ||
7466 	    base_type(arg_type) == ARG_PTR_TO_SPIN_LOCK)
7467 		arg_btf_id = fn->arg_btf_id[arg];
7468 
7469 	err = check_reg_type(env, regno, arg_type, arg_btf_id, meta);
7470 	if (err)
7471 		return err;
7472 
7473 	err = check_func_arg_reg_off(env, reg, regno, arg_type);
7474 	if (err)
7475 		return err;
7476 
7477 skip_type_check:
7478 	if (arg_type_is_release(arg_type)) {
7479 		if (arg_type_is_dynptr(arg_type)) {
7480 			struct bpf_func_state *state = func(env, reg);
7481 			int spi;
7482 
7483 			/* Only dynptr created on stack can be released, thus
7484 			 * the get_spi and stack state checks for spilled_ptr
7485 			 * should only be done before process_dynptr_func for
7486 			 * PTR_TO_STACK.
7487 			 */
7488 			if (reg->type == PTR_TO_STACK) {
7489 				spi = dynptr_get_spi(env, reg);
7490 				if (spi < 0 || !state->stack[spi].spilled_ptr.ref_obj_id) {
7491 					verbose(env, "arg %d is an unacquired reference\n", regno);
7492 					return -EINVAL;
7493 				}
7494 			} else {
7495 				verbose(env, "cannot release unowned const bpf_dynptr\n");
7496 				return -EINVAL;
7497 			}
7498 		} else if (!reg->ref_obj_id && !register_is_null(reg)) {
7499 			verbose(env, "R%d must be referenced when passed to release function\n",
7500 				regno);
7501 			return -EINVAL;
7502 		}
7503 		if (meta->release_regno) {
7504 			verbose(env, "verifier internal error: more than one release argument\n");
7505 			return -EFAULT;
7506 		}
7507 		meta->release_regno = regno;
7508 	}
7509 
7510 	if (reg->ref_obj_id) {
7511 		if (meta->ref_obj_id) {
7512 			verbose(env, "verifier internal error: more than one arg with ref_obj_id R%d %u %u\n",
7513 				regno, reg->ref_obj_id,
7514 				meta->ref_obj_id);
7515 			return -EFAULT;
7516 		}
7517 		meta->ref_obj_id = reg->ref_obj_id;
7518 	}
7519 
7520 	switch (base_type(arg_type)) {
7521 	case ARG_CONST_MAP_PTR:
7522 		/* bpf_map_xxx(map_ptr) call: remember that map_ptr */
7523 		if (meta->map_ptr) {
7524 			/* Use map_uid (which is unique id of inner map) to reject:
7525 			 * inner_map1 = bpf_map_lookup_elem(outer_map, key1)
7526 			 * inner_map2 = bpf_map_lookup_elem(outer_map, key2)
7527 			 * if (inner_map1 && inner_map2) {
7528 			 *     timer = bpf_map_lookup_elem(inner_map1);
7529 			 *     if (timer)
7530 			 *         // mismatch would have been allowed
7531 			 *         bpf_timer_init(timer, inner_map2);
7532 			 * }
7533 			 *
7534 			 * Comparing map_ptr is enough to distinguish normal and outer maps.
7535 			 */
7536 			if (meta->map_ptr != reg->map_ptr ||
7537 			    meta->map_uid != reg->map_uid) {
7538 				verbose(env,
7539 					"timer pointer in R1 map_uid=%d doesn't match map pointer in R2 map_uid=%d\n",
7540 					meta->map_uid, reg->map_uid);
7541 				return -EINVAL;
7542 			}
7543 		}
7544 		meta->map_ptr = reg->map_ptr;
7545 		meta->map_uid = reg->map_uid;
7546 		break;
7547 	case ARG_PTR_TO_MAP_KEY:
7548 		/* bpf_map_xxx(..., map_ptr, ..., key) call:
7549 		 * check that [key, key + map->key_size) are within
7550 		 * stack limits and initialized
7551 		 */
7552 		if (!meta->map_ptr) {
7553 			/* in function declaration map_ptr must come before
7554 			 * map_key, so that it's verified and known before
7555 			 * we have to check map_key here. Otherwise it means
7556 			 * that kernel subsystem misconfigured verifier
7557 			 */
7558 			verbose(env, "invalid map_ptr to access map->key\n");
7559 			return -EACCES;
7560 		}
7561 		err = check_helper_mem_access(env, regno,
7562 					      meta->map_ptr->key_size, false,
7563 					      NULL);
7564 		break;
7565 	case ARG_PTR_TO_MAP_VALUE:
7566 		if (type_may_be_null(arg_type) && register_is_null(reg))
7567 			return 0;
7568 
7569 		/* bpf_map_xxx(..., map_ptr, ..., value) call:
7570 		 * check [value, value + map->value_size) validity
7571 		 */
7572 		if (!meta->map_ptr) {
7573 			/* kernel subsystem misconfigured verifier */
7574 			verbose(env, "invalid map_ptr to access map->value\n");
7575 			return -EACCES;
7576 		}
7577 		meta->raw_mode = arg_type & MEM_UNINIT;
7578 		err = check_helper_mem_access(env, regno,
7579 					      meta->map_ptr->value_size, false,
7580 					      meta);
7581 		break;
7582 	case ARG_PTR_TO_PERCPU_BTF_ID:
7583 		if (!reg->btf_id) {
7584 			verbose(env, "Helper has invalid btf_id in R%d\n", regno);
7585 			return -EACCES;
7586 		}
7587 		meta->ret_btf = reg->btf;
7588 		meta->ret_btf_id = reg->btf_id;
7589 		break;
7590 	case ARG_PTR_TO_SPIN_LOCK:
7591 		if (in_rbtree_lock_required_cb(env)) {
7592 			verbose(env, "can't spin_{lock,unlock} in rbtree cb\n");
7593 			return -EACCES;
7594 		}
7595 		if (meta->func_id == BPF_FUNC_spin_lock) {
7596 			err = process_spin_lock(env, regno, true);
7597 			if (err)
7598 				return err;
7599 		} else if (meta->func_id == BPF_FUNC_spin_unlock) {
7600 			err = process_spin_lock(env, regno, false);
7601 			if (err)
7602 				return err;
7603 		} else {
7604 			verbose(env, "verifier internal error\n");
7605 			return -EFAULT;
7606 		}
7607 		break;
7608 	case ARG_PTR_TO_TIMER:
7609 		err = process_timer_func(env, regno, meta);
7610 		if (err)
7611 			return err;
7612 		break;
7613 	case ARG_PTR_TO_FUNC:
7614 		meta->subprogno = reg->subprogno;
7615 		break;
7616 	case ARG_PTR_TO_MEM:
7617 		/* The access to this pointer is only checked when we hit the
7618 		 * next is_mem_size argument below.
7619 		 */
7620 		meta->raw_mode = arg_type & MEM_UNINIT;
7621 		if (arg_type & MEM_FIXED_SIZE) {
7622 			err = check_helper_mem_access(env, regno,
7623 						      fn->arg_size[arg], false,
7624 						      meta);
7625 		}
7626 		break;
7627 	case ARG_CONST_SIZE:
7628 		err = check_mem_size_reg(env, reg, regno, false, meta);
7629 		break;
7630 	case ARG_CONST_SIZE_OR_ZERO:
7631 		err = check_mem_size_reg(env, reg, regno, true, meta);
7632 		break;
7633 	case ARG_PTR_TO_DYNPTR:
7634 		err = process_dynptr_func(env, regno, insn_idx, arg_type);
7635 		if (err)
7636 			return err;
7637 		break;
7638 	case ARG_CONST_ALLOC_SIZE_OR_ZERO:
7639 		if (!tnum_is_const(reg->var_off)) {
7640 			verbose(env, "R%d is not a known constant'\n",
7641 				regno);
7642 			return -EACCES;
7643 		}
7644 		meta->mem_size = reg->var_off.value;
7645 		err = mark_chain_precision(env, regno);
7646 		if (err)
7647 			return err;
7648 		break;
7649 	case ARG_PTR_TO_INT:
7650 	case ARG_PTR_TO_LONG:
7651 	{
7652 		int size = int_ptr_type_to_size(arg_type);
7653 
7654 		err = check_helper_mem_access(env, regno, size, false, meta);
7655 		if (err)
7656 			return err;
7657 		err = check_ptr_alignment(env, reg, 0, size, true);
7658 		break;
7659 	}
7660 	case ARG_PTR_TO_CONST_STR:
7661 	{
7662 		struct bpf_map *map = reg->map_ptr;
7663 		int map_off;
7664 		u64 map_addr;
7665 		char *str_ptr;
7666 
7667 		if (!bpf_map_is_rdonly(map)) {
7668 			verbose(env, "R%d does not point to a readonly map'\n", regno);
7669 			return -EACCES;
7670 		}
7671 
7672 		if (!tnum_is_const(reg->var_off)) {
7673 			verbose(env, "R%d is not a constant address'\n", regno);
7674 			return -EACCES;
7675 		}
7676 
7677 		if (!map->ops->map_direct_value_addr) {
7678 			verbose(env, "no direct value access support for this map type\n");
7679 			return -EACCES;
7680 		}
7681 
7682 		err = check_map_access(env, regno, reg->off,
7683 				       map->value_size - reg->off, false,
7684 				       ACCESS_HELPER);
7685 		if (err)
7686 			return err;
7687 
7688 		map_off = reg->off + reg->var_off.value;
7689 		err = map->ops->map_direct_value_addr(map, &map_addr, map_off);
7690 		if (err) {
7691 			verbose(env, "direct value access on string failed\n");
7692 			return err;
7693 		}
7694 
7695 		str_ptr = (char *)(long)(map_addr);
7696 		if (!strnchr(str_ptr + map_off, map->value_size - map_off, 0)) {
7697 			verbose(env, "string is not zero-terminated\n");
7698 			return -EINVAL;
7699 		}
7700 		break;
7701 	}
7702 	case ARG_PTR_TO_KPTR:
7703 		err = process_kptr_func(env, regno, meta);
7704 		if (err)
7705 			return err;
7706 		break;
7707 	}
7708 
7709 	return err;
7710 }
7711 
7712 static bool may_update_sockmap(struct bpf_verifier_env *env, int func_id)
7713 {
7714 	enum bpf_attach_type eatype = env->prog->expected_attach_type;
7715 	enum bpf_prog_type type = resolve_prog_type(env->prog);
7716 
7717 	if (func_id != BPF_FUNC_map_update_elem)
7718 		return false;
7719 
7720 	/* It's not possible to get access to a locked struct sock in these
7721 	 * contexts, so updating is safe.
7722 	 */
7723 	switch (type) {
7724 	case BPF_PROG_TYPE_TRACING:
7725 		if (eatype == BPF_TRACE_ITER)
7726 			return true;
7727 		break;
7728 	case BPF_PROG_TYPE_SOCKET_FILTER:
7729 	case BPF_PROG_TYPE_SCHED_CLS:
7730 	case BPF_PROG_TYPE_SCHED_ACT:
7731 	case BPF_PROG_TYPE_XDP:
7732 	case BPF_PROG_TYPE_SK_REUSEPORT:
7733 	case BPF_PROG_TYPE_FLOW_DISSECTOR:
7734 	case BPF_PROG_TYPE_SK_LOOKUP:
7735 		return true;
7736 	default:
7737 		break;
7738 	}
7739 
7740 	verbose(env, "cannot update sockmap in this context\n");
7741 	return false;
7742 }
7743 
7744 static bool allow_tail_call_in_subprogs(struct bpf_verifier_env *env)
7745 {
7746 	return env->prog->jit_requested &&
7747 	       bpf_jit_supports_subprog_tailcalls();
7748 }
7749 
7750 static int check_map_func_compatibility(struct bpf_verifier_env *env,
7751 					struct bpf_map *map, int func_id)
7752 {
7753 	if (!map)
7754 		return 0;
7755 
7756 	/* We need a two way check, first is from map perspective ... */
7757 	switch (map->map_type) {
7758 	case BPF_MAP_TYPE_PROG_ARRAY:
7759 		if (func_id != BPF_FUNC_tail_call)
7760 			goto error;
7761 		break;
7762 	case BPF_MAP_TYPE_PERF_EVENT_ARRAY:
7763 		if (func_id != BPF_FUNC_perf_event_read &&
7764 		    func_id != BPF_FUNC_perf_event_output &&
7765 		    func_id != BPF_FUNC_skb_output &&
7766 		    func_id != BPF_FUNC_perf_event_read_value &&
7767 		    func_id != BPF_FUNC_xdp_output)
7768 			goto error;
7769 		break;
7770 	case BPF_MAP_TYPE_RINGBUF:
7771 		if (func_id != BPF_FUNC_ringbuf_output &&
7772 		    func_id != BPF_FUNC_ringbuf_reserve &&
7773 		    func_id != BPF_FUNC_ringbuf_query &&
7774 		    func_id != BPF_FUNC_ringbuf_reserve_dynptr &&
7775 		    func_id != BPF_FUNC_ringbuf_submit_dynptr &&
7776 		    func_id != BPF_FUNC_ringbuf_discard_dynptr)
7777 			goto error;
7778 		break;
7779 	case BPF_MAP_TYPE_USER_RINGBUF:
7780 		if (func_id != BPF_FUNC_user_ringbuf_drain)
7781 			goto error;
7782 		break;
7783 	case BPF_MAP_TYPE_STACK_TRACE:
7784 		if (func_id != BPF_FUNC_get_stackid)
7785 			goto error;
7786 		break;
7787 	case BPF_MAP_TYPE_CGROUP_ARRAY:
7788 		if (func_id != BPF_FUNC_skb_under_cgroup &&
7789 		    func_id != BPF_FUNC_current_task_under_cgroup)
7790 			goto error;
7791 		break;
7792 	case BPF_MAP_TYPE_CGROUP_STORAGE:
7793 	case BPF_MAP_TYPE_PERCPU_CGROUP_STORAGE:
7794 		if (func_id != BPF_FUNC_get_local_storage)
7795 			goto error;
7796 		break;
7797 	case BPF_MAP_TYPE_DEVMAP:
7798 	case BPF_MAP_TYPE_DEVMAP_HASH:
7799 		if (func_id != BPF_FUNC_redirect_map &&
7800 		    func_id != BPF_FUNC_map_lookup_elem)
7801 			goto error;
7802 		break;
7803 	/* Restrict bpf side of cpumap and xskmap, open when use-cases
7804 	 * appear.
7805 	 */
7806 	case BPF_MAP_TYPE_CPUMAP:
7807 		if (func_id != BPF_FUNC_redirect_map)
7808 			goto error;
7809 		break;
7810 	case BPF_MAP_TYPE_XSKMAP:
7811 		if (func_id != BPF_FUNC_redirect_map &&
7812 		    func_id != BPF_FUNC_map_lookup_elem)
7813 			goto error;
7814 		break;
7815 	case BPF_MAP_TYPE_ARRAY_OF_MAPS:
7816 	case BPF_MAP_TYPE_HASH_OF_MAPS:
7817 		if (func_id != BPF_FUNC_map_lookup_elem)
7818 			goto error;
7819 		break;
7820 	case BPF_MAP_TYPE_SOCKMAP:
7821 		if (func_id != BPF_FUNC_sk_redirect_map &&
7822 		    func_id != BPF_FUNC_sock_map_update &&
7823 		    func_id != BPF_FUNC_map_delete_elem &&
7824 		    func_id != BPF_FUNC_msg_redirect_map &&
7825 		    func_id != BPF_FUNC_sk_select_reuseport &&
7826 		    func_id != BPF_FUNC_map_lookup_elem &&
7827 		    !may_update_sockmap(env, func_id))
7828 			goto error;
7829 		break;
7830 	case BPF_MAP_TYPE_SOCKHASH:
7831 		if (func_id != BPF_FUNC_sk_redirect_hash &&
7832 		    func_id != BPF_FUNC_sock_hash_update &&
7833 		    func_id != BPF_FUNC_map_delete_elem &&
7834 		    func_id != BPF_FUNC_msg_redirect_hash &&
7835 		    func_id != BPF_FUNC_sk_select_reuseport &&
7836 		    func_id != BPF_FUNC_map_lookup_elem &&
7837 		    !may_update_sockmap(env, func_id))
7838 			goto error;
7839 		break;
7840 	case BPF_MAP_TYPE_REUSEPORT_SOCKARRAY:
7841 		if (func_id != BPF_FUNC_sk_select_reuseport)
7842 			goto error;
7843 		break;
7844 	case BPF_MAP_TYPE_QUEUE:
7845 	case BPF_MAP_TYPE_STACK:
7846 		if (func_id != BPF_FUNC_map_peek_elem &&
7847 		    func_id != BPF_FUNC_map_pop_elem &&
7848 		    func_id != BPF_FUNC_map_push_elem)
7849 			goto error;
7850 		break;
7851 	case BPF_MAP_TYPE_SK_STORAGE:
7852 		if (func_id != BPF_FUNC_sk_storage_get &&
7853 		    func_id != BPF_FUNC_sk_storage_delete &&
7854 		    func_id != BPF_FUNC_kptr_xchg)
7855 			goto error;
7856 		break;
7857 	case BPF_MAP_TYPE_INODE_STORAGE:
7858 		if (func_id != BPF_FUNC_inode_storage_get &&
7859 		    func_id != BPF_FUNC_inode_storage_delete &&
7860 		    func_id != BPF_FUNC_kptr_xchg)
7861 			goto error;
7862 		break;
7863 	case BPF_MAP_TYPE_TASK_STORAGE:
7864 		if (func_id != BPF_FUNC_task_storage_get &&
7865 		    func_id != BPF_FUNC_task_storage_delete &&
7866 		    func_id != BPF_FUNC_kptr_xchg)
7867 			goto error;
7868 		break;
7869 	case BPF_MAP_TYPE_CGRP_STORAGE:
7870 		if (func_id != BPF_FUNC_cgrp_storage_get &&
7871 		    func_id != BPF_FUNC_cgrp_storage_delete &&
7872 		    func_id != BPF_FUNC_kptr_xchg)
7873 			goto error;
7874 		break;
7875 	case BPF_MAP_TYPE_BLOOM_FILTER:
7876 		if (func_id != BPF_FUNC_map_peek_elem &&
7877 		    func_id != BPF_FUNC_map_push_elem)
7878 			goto error;
7879 		break;
7880 	default:
7881 		break;
7882 	}
7883 
7884 	/* ... and second from the function itself. */
7885 	switch (func_id) {
7886 	case BPF_FUNC_tail_call:
7887 		if (map->map_type != BPF_MAP_TYPE_PROG_ARRAY)
7888 			goto error;
7889 		if (env->subprog_cnt > 1 && !allow_tail_call_in_subprogs(env)) {
7890 			verbose(env, "tail_calls are not allowed in non-JITed programs with bpf-to-bpf calls\n");
7891 			return -EINVAL;
7892 		}
7893 		break;
7894 	case BPF_FUNC_perf_event_read:
7895 	case BPF_FUNC_perf_event_output:
7896 	case BPF_FUNC_perf_event_read_value:
7897 	case BPF_FUNC_skb_output:
7898 	case BPF_FUNC_xdp_output:
7899 		if (map->map_type != BPF_MAP_TYPE_PERF_EVENT_ARRAY)
7900 			goto error;
7901 		break;
7902 	case BPF_FUNC_ringbuf_output:
7903 	case BPF_FUNC_ringbuf_reserve:
7904 	case BPF_FUNC_ringbuf_query:
7905 	case BPF_FUNC_ringbuf_reserve_dynptr:
7906 	case BPF_FUNC_ringbuf_submit_dynptr:
7907 	case BPF_FUNC_ringbuf_discard_dynptr:
7908 		if (map->map_type != BPF_MAP_TYPE_RINGBUF)
7909 			goto error;
7910 		break;
7911 	case BPF_FUNC_user_ringbuf_drain:
7912 		if (map->map_type != BPF_MAP_TYPE_USER_RINGBUF)
7913 			goto error;
7914 		break;
7915 	case BPF_FUNC_get_stackid:
7916 		if (map->map_type != BPF_MAP_TYPE_STACK_TRACE)
7917 			goto error;
7918 		break;
7919 	case BPF_FUNC_current_task_under_cgroup:
7920 	case BPF_FUNC_skb_under_cgroup:
7921 		if (map->map_type != BPF_MAP_TYPE_CGROUP_ARRAY)
7922 			goto error;
7923 		break;
7924 	case BPF_FUNC_redirect_map:
7925 		if (map->map_type != BPF_MAP_TYPE_DEVMAP &&
7926 		    map->map_type != BPF_MAP_TYPE_DEVMAP_HASH &&
7927 		    map->map_type != BPF_MAP_TYPE_CPUMAP &&
7928 		    map->map_type != BPF_MAP_TYPE_XSKMAP)
7929 			goto error;
7930 		break;
7931 	case BPF_FUNC_sk_redirect_map:
7932 	case BPF_FUNC_msg_redirect_map:
7933 	case BPF_FUNC_sock_map_update:
7934 		if (map->map_type != BPF_MAP_TYPE_SOCKMAP)
7935 			goto error;
7936 		break;
7937 	case BPF_FUNC_sk_redirect_hash:
7938 	case BPF_FUNC_msg_redirect_hash:
7939 	case BPF_FUNC_sock_hash_update:
7940 		if (map->map_type != BPF_MAP_TYPE_SOCKHASH)
7941 			goto error;
7942 		break;
7943 	case BPF_FUNC_get_local_storage:
7944 		if (map->map_type != BPF_MAP_TYPE_CGROUP_STORAGE &&
7945 		    map->map_type != BPF_MAP_TYPE_PERCPU_CGROUP_STORAGE)
7946 			goto error;
7947 		break;
7948 	case BPF_FUNC_sk_select_reuseport:
7949 		if (map->map_type != BPF_MAP_TYPE_REUSEPORT_SOCKARRAY &&
7950 		    map->map_type != BPF_MAP_TYPE_SOCKMAP &&
7951 		    map->map_type != BPF_MAP_TYPE_SOCKHASH)
7952 			goto error;
7953 		break;
7954 	case BPF_FUNC_map_pop_elem:
7955 		if (map->map_type != BPF_MAP_TYPE_QUEUE &&
7956 		    map->map_type != BPF_MAP_TYPE_STACK)
7957 			goto error;
7958 		break;
7959 	case BPF_FUNC_map_peek_elem:
7960 	case BPF_FUNC_map_push_elem:
7961 		if (map->map_type != BPF_MAP_TYPE_QUEUE &&
7962 		    map->map_type != BPF_MAP_TYPE_STACK &&
7963 		    map->map_type != BPF_MAP_TYPE_BLOOM_FILTER)
7964 			goto error;
7965 		break;
7966 	case BPF_FUNC_map_lookup_percpu_elem:
7967 		if (map->map_type != BPF_MAP_TYPE_PERCPU_ARRAY &&
7968 		    map->map_type != BPF_MAP_TYPE_PERCPU_HASH &&
7969 		    map->map_type != BPF_MAP_TYPE_LRU_PERCPU_HASH)
7970 			goto error;
7971 		break;
7972 	case BPF_FUNC_sk_storage_get:
7973 	case BPF_FUNC_sk_storage_delete:
7974 		if (map->map_type != BPF_MAP_TYPE_SK_STORAGE)
7975 			goto error;
7976 		break;
7977 	case BPF_FUNC_inode_storage_get:
7978 	case BPF_FUNC_inode_storage_delete:
7979 		if (map->map_type != BPF_MAP_TYPE_INODE_STORAGE)
7980 			goto error;
7981 		break;
7982 	case BPF_FUNC_task_storage_get:
7983 	case BPF_FUNC_task_storage_delete:
7984 		if (map->map_type != BPF_MAP_TYPE_TASK_STORAGE)
7985 			goto error;
7986 		break;
7987 	case BPF_FUNC_cgrp_storage_get:
7988 	case BPF_FUNC_cgrp_storage_delete:
7989 		if (map->map_type != BPF_MAP_TYPE_CGRP_STORAGE)
7990 			goto error;
7991 		break;
7992 	default:
7993 		break;
7994 	}
7995 
7996 	return 0;
7997 error:
7998 	verbose(env, "cannot pass map_type %d into func %s#%d\n",
7999 		map->map_type, func_id_name(func_id), func_id);
8000 	return -EINVAL;
8001 }
8002 
8003 static bool check_raw_mode_ok(const struct bpf_func_proto *fn)
8004 {
8005 	int count = 0;
8006 
8007 	if (fn->arg1_type == ARG_PTR_TO_UNINIT_MEM)
8008 		count++;
8009 	if (fn->arg2_type == ARG_PTR_TO_UNINIT_MEM)
8010 		count++;
8011 	if (fn->arg3_type == ARG_PTR_TO_UNINIT_MEM)
8012 		count++;
8013 	if (fn->arg4_type == ARG_PTR_TO_UNINIT_MEM)
8014 		count++;
8015 	if (fn->arg5_type == ARG_PTR_TO_UNINIT_MEM)
8016 		count++;
8017 
8018 	/* We only support one arg being in raw mode at the moment,
8019 	 * which is sufficient for the helper functions we have
8020 	 * right now.
8021 	 */
8022 	return count <= 1;
8023 }
8024 
8025 static bool check_args_pair_invalid(const struct bpf_func_proto *fn, int arg)
8026 {
8027 	bool is_fixed = fn->arg_type[arg] & MEM_FIXED_SIZE;
8028 	bool has_size = fn->arg_size[arg] != 0;
8029 	bool is_next_size = false;
8030 
8031 	if (arg + 1 < ARRAY_SIZE(fn->arg_type))
8032 		is_next_size = arg_type_is_mem_size(fn->arg_type[arg + 1]);
8033 
8034 	if (base_type(fn->arg_type[arg]) != ARG_PTR_TO_MEM)
8035 		return is_next_size;
8036 
8037 	return has_size == is_next_size || is_next_size == is_fixed;
8038 }
8039 
8040 static bool check_arg_pair_ok(const struct bpf_func_proto *fn)
8041 {
8042 	/* bpf_xxx(..., buf, len) call will access 'len'
8043 	 * bytes from memory 'buf'. Both arg types need
8044 	 * to be paired, so make sure there's no buggy
8045 	 * helper function specification.
8046 	 */
8047 	if (arg_type_is_mem_size(fn->arg1_type) ||
8048 	    check_args_pair_invalid(fn, 0) ||
8049 	    check_args_pair_invalid(fn, 1) ||
8050 	    check_args_pair_invalid(fn, 2) ||
8051 	    check_args_pair_invalid(fn, 3) ||
8052 	    check_args_pair_invalid(fn, 4))
8053 		return false;
8054 
8055 	return true;
8056 }
8057 
8058 static bool check_btf_id_ok(const struct bpf_func_proto *fn)
8059 {
8060 	int i;
8061 
8062 	for (i = 0; i < ARRAY_SIZE(fn->arg_type); i++) {
8063 		if (base_type(fn->arg_type[i]) == ARG_PTR_TO_BTF_ID)
8064 			return !!fn->arg_btf_id[i];
8065 		if (base_type(fn->arg_type[i]) == ARG_PTR_TO_SPIN_LOCK)
8066 			return fn->arg_btf_id[i] == BPF_PTR_POISON;
8067 		if (base_type(fn->arg_type[i]) != ARG_PTR_TO_BTF_ID && fn->arg_btf_id[i] &&
8068 		    /* arg_btf_id and arg_size are in a union. */
8069 		    (base_type(fn->arg_type[i]) != ARG_PTR_TO_MEM ||
8070 		     !(fn->arg_type[i] & MEM_FIXED_SIZE)))
8071 			return false;
8072 	}
8073 
8074 	return true;
8075 }
8076 
8077 static int check_func_proto(const struct bpf_func_proto *fn, int func_id)
8078 {
8079 	return check_raw_mode_ok(fn) &&
8080 	       check_arg_pair_ok(fn) &&
8081 	       check_btf_id_ok(fn) ? 0 : -EINVAL;
8082 }
8083 
8084 /* Packet data might have moved, any old PTR_TO_PACKET[_META,_END]
8085  * are now invalid, so turn them into unknown SCALAR_VALUE.
8086  *
8087  * This also applies to dynptr slices belonging to skb and xdp dynptrs,
8088  * since these slices point to packet data.
8089  */
8090 static void clear_all_pkt_pointers(struct bpf_verifier_env *env)
8091 {
8092 	struct bpf_func_state *state;
8093 	struct bpf_reg_state *reg;
8094 
8095 	bpf_for_each_reg_in_vstate(env->cur_state, state, reg, ({
8096 		if (reg_is_pkt_pointer_any(reg) || reg_is_dynptr_slice_pkt(reg))
8097 			mark_reg_invalid(env, reg);
8098 	}));
8099 }
8100 
8101 enum {
8102 	AT_PKT_END = -1,
8103 	BEYOND_PKT_END = -2,
8104 };
8105 
8106 static void mark_pkt_end(struct bpf_verifier_state *vstate, int regn, bool range_open)
8107 {
8108 	struct bpf_func_state *state = vstate->frame[vstate->curframe];
8109 	struct bpf_reg_state *reg = &state->regs[regn];
8110 
8111 	if (reg->type != PTR_TO_PACKET)
8112 		/* PTR_TO_PACKET_META is not supported yet */
8113 		return;
8114 
8115 	/* The 'reg' is pkt > pkt_end or pkt >= pkt_end.
8116 	 * How far beyond pkt_end it goes is unknown.
8117 	 * if (!range_open) it's the case of pkt >= pkt_end
8118 	 * if (range_open) it's the case of pkt > pkt_end
8119 	 * hence this pointer is at least 1 byte bigger than pkt_end
8120 	 */
8121 	if (range_open)
8122 		reg->range = BEYOND_PKT_END;
8123 	else
8124 		reg->range = AT_PKT_END;
8125 }
8126 
8127 /* The pointer with the specified id has released its reference to kernel
8128  * resources. Identify all copies of the same pointer and clear the reference.
8129  */
8130 static int release_reference(struct bpf_verifier_env *env,
8131 			     int ref_obj_id)
8132 {
8133 	struct bpf_func_state *state;
8134 	struct bpf_reg_state *reg;
8135 	int err;
8136 
8137 	err = release_reference_state(cur_func(env), ref_obj_id);
8138 	if (err)
8139 		return err;
8140 
8141 	bpf_for_each_reg_in_vstate(env->cur_state, state, reg, ({
8142 		if (reg->ref_obj_id == ref_obj_id)
8143 			mark_reg_invalid(env, reg);
8144 	}));
8145 
8146 	return 0;
8147 }
8148 
8149 static void invalidate_non_owning_refs(struct bpf_verifier_env *env)
8150 {
8151 	struct bpf_func_state *unused;
8152 	struct bpf_reg_state *reg;
8153 
8154 	bpf_for_each_reg_in_vstate(env->cur_state, unused, reg, ({
8155 		if (type_is_non_owning_ref(reg->type))
8156 			mark_reg_invalid(env, reg);
8157 	}));
8158 }
8159 
8160 static void clear_caller_saved_regs(struct bpf_verifier_env *env,
8161 				    struct bpf_reg_state *regs)
8162 {
8163 	int i;
8164 
8165 	/* after the call registers r0 - r5 were scratched */
8166 	for (i = 0; i < CALLER_SAVED_REGS; i++) {
8167 		mark_reg_not_init(env, regs, caller_saved[i]);
8168 		check_reg_arg(env, caller_saved[i], DST_OP_NO_MARK);
8169 	}
8170 }
8171 
8172 typedef int (*set_callee_state_fn)(struct bpf_verifier_env *env,
8173 				   struct bpf_func_state *caller,
8174 				   struct bpf_func_state *callee,
8175 				   int insn_idx);
8176 
8177 static int set_callee_state(struct bpf_verifier_env *env,
8178 			    struct bpf_func_state *caller,
8179 			    struct bpf_func_state *callee, int insn_idx);
8180 
8181 static bool is_callback_calling_kfunc(u32 btf_id);
8182 
8183 static int __check_func_call(struct bpf_verifier_env *env, struct bpf_insn *insn,
8184 			     int *insn_idx, int subprog,
8185 			     set_callee_state_fn set_callee_state_cb)
8186 {
8187 	struct bpf_verifier_state *state = env->cur_state;
8188 	struct bpf_func_info_aux *func_info_aux;
8189 	struct bpf_func_state *caller, *callee;
8190 	int err;
8191 	bool is_global = false;
8192 
8193 	if (state->curframe + 1 >= MAX_CALL_FRAMES) {
8194 		verbose(env, "the call stack of %d frames is too deep\n",
8195 			state->curframe + 2);
8196 		return -E2BIG;
8197 	}
8198 
8199 	caller = state->frame[state->curframe];
8200 	if (state->frame[state->curframe + 1]) {
8201 		verbose(env, "verifier bug. Frame %d already allocated\n",
8202 			state->curframe + 1);
8203 		return -EFAULT;
8204 	}
8205 
8206 	func_info_aux = env->prog->aux->func_info_aux;
8207 	if (func_info_aux)
8208 		is_global = func_info_aux[subprog].linkage == BTF_FUNC_GLOBAL;
8209 	err = btf_check_subprog_call(env, subprog, caller->regs);
8210 	if (err == -EFAULT)
8211 		return err;
8212 	if (is_global) {
8213 		if (err) {
8214 			verbose(env, "Caller passes invalid args into func#%d\n",
8215 				subprog);
8216 			return err;
8217 		} else {
8218 			if (env->log.level & BPF_LOG_LEVEL)
8219 				verbose(env,
8220 					"Func#%d is global and valid. Skipping.\n",
8221 					subprog);
8222 			clear_caller_saved_regs(env, caller->regs);
8223 
8224 			/* All global functions return a 64-bit SCALAR_VALUE */
8225 			mark_reg_unknown(env, caller->regs, BPF_REG_0);
8226 			caller->regs[BPF_REG_0].subreg_def = DEF_NOT_SUBREG;
8227 
8228 			/* continue with next insn after call */
8229 			return 0;
8230 		}
8231 	}
8232 
8233 	/* set_callee_state is used for direct subprog calls, but we are
8234 	 * interested in validating only BPF helpers that can call subprogs as
8235 	 * callbacks
8236 	 */
8237 	if (set_callee_state_cb != set_callee_state) {
8238 		if (bpf_pseudo_kfunc_call(insn) &&
8239 		    !is_callback_calling_kfunc(insn->imm)) {
8240 			verbose(env, "verifier bug: kfunc %s#%d not marked as callback-calling\n",
8241 				func_id_name(insn->imm), insn->imm);
8242 			return -EFAULT;
8243 		} else if (!bpf_pseudo_kfunc_call(insn) &&
8244 			   !is_callback_calling_function(insn->imm)) { /* helper */
8245 			verbose(env, "verifier bug: helper %s#%d not marked as callback-calling\n",
8246 				func_id_name(insn->imm), insn->imm);
8247 			return -EFAULT;
8248 		}
8249 	}
8250 
8251 	if (insn->code == (BPF_JMP | BPF_CALL) &&
8252 	    insn->src_reg == 0 &&
8253 	    insn->imm == BPF_FUNC_timer_set_callback) {
8254 		struct bpf_verifier_state *async_cb;
8255 
8256 		/* there is no real recursion here. timer callbacks are async */
8257 		env->subprog_info[subprog].is_async_cb = true;
8258 		async_cb = push_async_cb(env, env->subprog_info[subprog].start,
8259 					 *insn_idx, subprog);
8260 		if (!async_cb)
8261 			return -EFAULT;
8262 		callee = async_cb->frame[0];
8263 		callee->async_entry_cnt = caller->async_entry_cnt + 1;
8264 
8265 		/* Convert bpf_timer_set_callback() args into timer callback args */
8266 		err = set_callee_state_cb(env, caller, callee, *insn_idx);
8267 		if (err)
8268 			return err;
8269 
8270 		clear_caller_saved_regs(env, caller->regs);
8271 		mark_reg_unknown(env, caller->regs, BPF_REG_0);
8272 		caller->regs[BPF_REG_0].subreg_def = DEF_NOT_SUBREG;
8273 		/* continue with next insn after call */
8274 		return 0;
8275 	}
8276 
8277 	callee = kzalloc(sizeof(*callee), GFP_KERNEL);
8278 	if (!callee)
8279 		return -ENOMEM;
8280 	state->frame[state->curframe + 1] = callee;
8281 
8282 	/* callee cannot access r0, r6 - r9 for reading and has to write
8283 	 * into its own stack before reading from it.
8284 	 * callee can read/write into caller's stack
8285 	 */
8286 	init_func_state(env, callee,
8287 			/* remember the callsite, it will be used by bpf_exit */
8288 			*insn_idx /* callsite */,
8289 			state->curframe + 1 /* frameno within this callchain */,
8290 			subprog /* subprog number within this prog */);
8291 
8292 	/* Transfer references to the callee */
8293 	err = copy_reference_state(callee, caller);
8294 	if (err)
8295 		goto err_out;
8296 
8297 	err = set_callee_state_cb(env, caller, callee, *insn_idx);
8298 	if (err)
8299 		goto err_out;
8300 
8301 	clear_caller_saved_regs(env, caller->regs);
8302 
8303 	/* only increment it after check_reg_arg() finished */
8304 	state->curframe++;
8305 
8306 	/* and go analyze first insn of the callee */
8307 	*insn_idx = env->subprog_info[subprog].start - 1;
8308 
8309 	if (env->log.level & BPF_LOG_LEVEL) {
8310 		verbose(env, "caller:\n");
8311 		print_verifier_state(env, caller, true);
8312 		verbose(env, "callee:\n");
8313 		print_verifier_state(env, callee, true);
8314 	}
8315 	return 0;
8316 
8317 err_out:
8318 	free_func_state(callee);
8319 	state->frame[state->curframe + 1] = NULL;
8320 	return err;
8321 }
8322 
8323 int map_set_for_each_callback_args(struct bpf_verifier_env *env,
8324 				   struct bpf_func_state *caller,
8325 				   struct bpf_func_state *callee)
8326 {
8327 	/* bpf_for_each_map_elem(struct bpf_map *map, void *callback_fn,
8328 	 *      void *callback_ctx, u64 flags);
8329 	 * callback_fn(struct bpf_map *map, void *key, void *value,
8330 	 *      void *callback_ctx);
8331 	 */
8332 	callee->regs[BPF_REG_1] = caller->regs[BPF_REG_1];
8333 
8334 	callee->regs[BPF_REG_2].type = PTR_TO_MAP_KEY;
8335 	__mark_reg_known_zero(&callee->regs[BPF_REG_2]);
8336 	callee->regs[BPF_REG_2].map_ptr = caller->regs[BPF_REG_1].map_ptr;
8337 
8338 	callee->regs[BPF_REG_3].type = PTR_TO_MAP_VALUE;
8339 	__mark_reg_known_zero(&callee->regs[BPF_REG_3]);
8340 	callee->regs[BPF_REG_3].map_ptr = caller->regs[BPF_REG_1].map_ptr;
8341 
8342 	/* pointer to stack or null */
8343 	callee->regs[BPF_REG_4] = caller->regs[BPF_REG_3];
8344 
8345 	/* unused */
8346 	__mark_reg_not_init(env, &callee->regs[BPF_REG_5]);
8347 	return 0;
8348 }
8349 
8350 static int set_callee_state(struct bpf_verifier_env *env,
8351 			    struct bpf_func_state *caller,
8352 			    struct bpf_func_state *callee, int insn_idx)
8353 {
8354 	int i;
8355 
8356 	/* copy r1 - r5 args that callee can access.  The copy includes parent
8357 	 * pointers, which connects us up to the liveness chain
8358 	 */
8359 	for (i = BPF_REG_1; i <= BPF_REG_5; i++)
8360 		callee->regs[i] = caller->regs[i];
8361 	return 0;
8362 }
8363 
8364 static int check_func_call(struct bpf_verifier_env *env, struct bpf_insn *insn,
8365 			   int *insn_idx)
8366 {
8367 	int subprog, target_insn;
8368 
8369 	target_insn = *insn_idx + insn->imm + 1;
8370 	subprog = find_subprog(env, target_insn);
8371 	if (subprog < 0) {
8372 		verbose(env, "verifier bug. No program starts at insn %d\n",
8373 			target_insn);
8374 		return -EFAULT;
8375 	}
8376 
8377 	return __check_func_call(env, insn, insn_idx, subprog, set_callee_state);
8378 }
8379 
8380 static int set_map_elem_callback_state(struct bpf_verifier_env *env,
8381 				       struct bpf_func_state *caller,
8382 				       struct bpf_func_state *callee,
8383 				       int insn_idx)
8384 {
8385 	struct bpf_insn_aux_data *insn_aux = &env->insn_aux_data[insn_idx];
8386 	struct bpf_map *map;
8387 	int err;
8388 
8389 	if (bpf_map_ptr_poisoned(insn_aux)) {
8390 		verbose(env, "tail_call abusing map_ptr\n");
8391 		return -EINVAL;
8392 	}
8393 
8394 	map = BPF_MAP_PTR(insn_aux->map_ptr_state);
8395 	if (!map->ops->map_set_for_each_callback_args ||
8396 	    !map->ops->map_for_each_callback) {
8397 		verbose(env, "callback function not allowed for map\n");
8398 		return -ENOTSUPP;
8399 	}
8400 
8401 	err = map->ops->map_set_for_each_callback_args(env, caller, callee);
8402 	if (err)
8403 		return err;
8404 
8405 	callee->in_callback_fn = true;
8406 	callee->callback_ret_range = tnum_range(0, 1);
8407 	return 0;
8408 }
8409 
8410 static int set_loop_callback_state(struct bpf_verifier_env *env,
8411 				   struct bpf_func_state *caller,
8412 				   struct bpf_func_state *callee,
8413 				   int insn_idx)
8414 {
8415 	/* bpf_loop(u32 nr_loops, void *callback_fn, void *callback_ctx,
8416 	 *	    u64 flags);
8417 	 * callback_fn(u32 index, void *callback_ctx);
8418 	 */
8419 	callee->regs[BPF_REG_1].type = SCALAR_VALUE;
8420 	callee->regs[BPF_REG_2] = caller->regs[BPF_REG_3];
8421 
8422 	/* unused */
8423 	__mark_reg_not_init(env, &callee->regs[BPF_REG_3]);
8424 	__mark_reg_not_init(env, &callee->regs[BPF_REG_4]);
8425 	__mark_reg_not_init(env, &callee->regs[BPF_REG_5]);
8426 
8427 	callee->in_callback_fn = true;
8428 	callee->callback_ret_range = tnum_range(0, 1);
8429 	return 0;
8430 }
8431 
8432 static int set_timer_callback_state(struct bpf_verifier_env *env,
8433 				    struct bpf_func_state *caller,
8434 				    struct bpf_func_state *callee,
8435 				    int insn_idx)
8436 {
8437 	struct bpf_map *map_ptr = caller->regs[BPF_REG_1].map_ptr;
8438 
8439 	/* bpf_timer_set_callback(struct bpf_timer *timer, void *callback_fn);
8440 	 * callback_fn(struct bpf_map *map, void *key, void *value);
8441 	 */
8442 	callee->regs[BPF_REG_1].type = CONST_PTR_TO_MAP;
8443 	__mark_reg_known_zero(&callee->regs[BPF_REG_1]);
8444 	callee->regs[BPF_REG_1].map_ptr = map_ptr;
8445 
8446 	callee->regs[BPF_REG_2].type = PTR_TO_MAP_KEY;
8447 	__mark_reg_known_zero(&callee->regs[BPF_REG_2]);
8448 	callee->regs[BPF_REG_2].map_ptr = map_ptr;
8449 
8450 	callee->regs[BPF_REG_3].type = PTR_TO_MAP_VALUE;
8451 	__mark_reg_known_zero(&callee->regs[BPF_REG_3]);
8452 	callee->regs[BPF_REG_3].map_ptr = map_ptr;
8453 
8454 	/* unused */
8455 	__mark_reg_not_init(env, &callee->regs[BPF_REG_4]);
8456 	__mark_reg_not_init(env, &callee->regs[BPF_REG_5]);
8457 	callee->in_async_callback_fn = true;
8458 	callee->callback_ret_range = tnum_range(0, 1);
8459 	return 0;
8460 }
8461 
8462 static int set_find_vma_callback_state(struct bpf_verifier_env *env,
8463 				       struct bpf_func_state *caller,
8464 				       struct bpf_func_state *callee,
8465 				       int insn_idx)
8466 {
8467 	/* bpf_find_vma(struct task_struct *task, u64 addr,
8468 	 *               void *callback_fn, void *callback_ctx, u64 flags)
8469 	 * (callback_fn)(struct task_struct *task,
8470 	 *               struct vm_area_struct *vma, void *callback_ctx);
8471 	 */
8472 	callee->regs[BPF_REG_1] = caller->regs[BPF_REG_1];
8473 
8474 	callee->regs[BPF_REG_2].type = PTR_TO_BTF_ID;
8475 	__mark_reg_known_zero(&callee->regs[BPF_REG_2]);
8476 	callee->regs[BPF_REG_2].btf =  btf_vmlinux;
8477 	callee->regs[BPF_REG_2].btf_id = btf_tracing_ids[BTF_TRACING_TYPE_VMA],
8478 
8479 	/* pointer to stack or null */
8480 	callee->regs[BPF_REG_3] = caller->regs[BPF_REG_4];
8481 
8482 	/* unused */
8483 	__mark_reg_not_init(env, &callee->regs[BPF_REG_4]);
8484 	__mark_reg_not_init(env, &callee->regs[BPF_REG_5]);
8485 	callee->in_callback_fn = true;
8486 	callee->callback_ret_range = tnum_range(0, 1);
8487 	return 0;
8488 }
8489 
8490 static int set_user_ringbuf_callback_state(struct bpf_verifier_env *env,
8491 					   struct bpf_func_state *caller,
8492 					   struct bpf_func_state *callee,
8493 					   int insn_idx)
8494 {
8495 	/* bpf_user_ringbuf_drain(struct bpf_map *map, void *callback_fn, void
8496 	 *			  callback_ctx, u64 flags);
8497 	 * callback_fn(const struct bpf_dynptr_t* dynptr, void *callback_ctx);
8498 	 */
8499 	__mark_reg_not_init(env, &callee->regs[BPF_REG_0]);
8500 	mark_dynptr_cb_reg(env, &callee->regs[BPF_REG_1], BPF_DYNPTR_TYPE_LOCAL);
8501 	callee->regs[BPF_REG_2] = caller->regs[BPF_REG_3];
8502 
8503 	/* unused */
8504 	__mark_reg_not_init(env, &callee->regs[BPF_REG_3]);
8505 	__mark_reg_not_init(env, &callee->regs[BPF_REG_4]);
8506 	__mark_reg_not_init(env, &callee->regs[BPF_REG_5]);
8507 
8508 	callee->in_callback_fn = true;
8509 	callee->callback_ret_range = tnum_range(0, 1);
8510 	return 0;
8511 }
8512 
8513 static int set_rbtree_add_callback_state(struct bpf_verifier_env *env,
8514 					 struct bpf_func_state *caller,
8515 					 struct bpf_func_state *callee,
8516 					 int insn_idx)
8517 {
8518 	/* void bpf_rbtree_add_impl(struct bpf_rb_root *root, struct bpf_rb_node *node,
8519 	 *                     bool (less)(struct bpf_rb_node *a, const struct bpf_rb_node *b));
8520 	 *
8521 	 * 'struct bpf_rb_node *node' arg to bpf_rbtree_add_impl is the same PTR_TO_BTF_ID w/ offset
8522 	 * that 'less' callback args will be receiving. However, 'node' arg was release_reference'd
8523 	 * by this point, so look at 'root'
8524 	 */
8525 	struct btf_field *field;
8526 
8527 	field = reg_find_field_offset(&caller->regs[BPF_REG_1], caller->regs[BPF_REG_1].off,
8528 				      BPF_RB_ROOT);
8529 	if (!field || !field->graph_root.value_btf_id)
8530 		return -EFAULT;
8531 
8532 	mark_reg_graph_node(callee->regs, BPF_REG_1, &field->graph_root);
8533 	ref_set_non_owning(env, &callee->regs[BPF_REG_1]);
8534 	mark_reg_graph_node(callee->regs, BPF_REG_2, &field->graph_root);
8535 	ref_set_non_owning(env, &callee->regs[BPF_REG_2]);
8536 
8537 	__mark_reg_not_init(env, &callee->regs[BPF_REG_3]);
8538 	__mark_reg_not_init(env, &callee->regs[BPF_REG_4]);
8539 	__mark_reg_not_init(env, &callee->regs[BPF_REG_5]);
8540 	callee->in_callback_fn = true;
8541 	callee->callback_ret_range = tnum_range(0, 1);
8542 	return 0;
8543 }
8544 
8545 static bool is_rbtree_lock_required_kfunc(u32 btf_id);
8546 
8547 /* Are we currently verifying the callback for a rbtree helper that must
8548  * be called with lock held? If so, no need to complain about unreleased
8549  * lock
8550  */
8551 static bool in_rbtree_lock_required_cb(struct bpf_verifier_env *env)
8552 {
8553 	struct bpf_verifier_state *state = env->cur_state;
8554 	struct bpf_insn *insn = env->prog->insnsi;
8555 	struct bpf_func_state *callee;
8556 	int kfunc_btf_id;
8557 
8558 	if (!state->curframe)
8559 		return false;
8560 
8561 	callee = state->frame[state->curframe];
8562 
8563 	if (!callee->in_callback_fn)
8564 		return false;
8565 
8566 	kfunc_btf_id = insn[callee->callsite].imm;
8567 	return is_rbtree_lock_required_kfunc(kfunc_btf_id);
8568 }
8569 
8570 static int prepare_func_exit(struct bpf_verifier_env *env, int *insn_idx)
8571 {
8572 	struct bpf_verifier_state *state = env->cur_state;
8573 	struct bpf_func_state *caller, *callee;
8574 	struct bpf_reg_state *r0;
8575 	int err;
8576 
8577 	callee = state->frame[state->curframe];
8578 	r0 = &callee->regs[BPF_REG_0];
8579 	if (r0->type == PTR_TO_STACK) {
8580 		/* technically it's ok to return caller's stack pointer
8581 		 * (or caller's caller's pointer) back to the caller,
8582 		 * since these pointers are valid. Only current stack
8583 		 * pointer will be invalid as soon as function exits,
8584 		 * but let's be conservative
8585 		 */
8586 		verbose(env, "cannot return stack pointer to the caller\n");
8587 		return -EINVAL;
8588 	}
8589 
8590 	caller = state->frame[state->curframe - 1];
8591 	if (callee->in_callback_fn) {
8592 		/* enforce R0 return value range [0, 1]. */
8593 		struct tnum range = callee->callback_ret_range;
8594 
8595 		if (r0->type != SCALAR_VALUE) {
8596 			verbose(env, "R0 not a scalar value\n");
8597 			return -EACCES;
8598 		}
8599 		if (!tnum_in(range, r0->var_off)) {
8600 			verbose_invalid_scalar(env, r0, &range, "callback return", "R0");
8601 			return -EINVAL;
8602 		}
8603 	} else {
8604 		/* return to the caller whatever r0 had in the callee */
8605 		caller->regs[BPF_REG_0] = *r0;
8606 	}
8607 
8608 	/* callback_fn frame should have released its own additions to parent's
8609 	 * reference state at this point, or check_reference_leak would
8610 	 * complain, hence it must be the same as the caller. There is no need
8611 	 * to copy it back.
8612 	 */
8613 	if (!callee->in_callback_fn) {
8614 		/* Transfer references to the caller */
8615 		err = copy_reference_state(caller, callee);
8616 		if (err)
8617 			return err;
8618 	}
8619 
8620 	*insn_idx = callee->callsite + 1;
8621 	if (env->log.level & BPF_LOG_LEVEL) {
8622 		verbose(env, "returning from callee:\n");
8623 		print_verifier_state(env, callee, true);
8624 		verbose(env, "to caller at %d:\n", *insn_idx);
8625 		print_verifier_state(env, caller, true);
8626 	}
8627 	/* clear everything in the callee */
8628 	free_func_state(callee);
8629 	state->frame[state->curframe--] = NULL;
8630 	return 0;
8631 }
8632 
8633 static void do_refine_retval_range(struct bpf_reg_state *regs, int ret_type,
8634 				   int func_id,
8635 				   struct bpf_call_arg_meta *meta)
8636 {
8637 	struct bpf_reg_state *ret_reg = &regs[BPF_REG_0];
8638 
8639 	if (ret_type != RET_INTEGER ||
8640 	    (func_id != BPF_FUNC_get_stack &&
8641 	     func_id != BPF_FUNC_get_task_stack &&
8642 	     func_id != BPF_FUNC_probe_read_str &&
8643 	     func_id != BPF_FUNC_probe_read_kernel_str &&
8644 	     func_id != BPF_FUNC_probe_read_user_str))
8645 		return;
8646 
8647 	ret_reg->smax_value = meta->msize_max_value;
8648 	ret_reg->s32_max_value = meta->msize_max_value;
8649 	ret_reg->smin_value = -MAX_ERRNO;
8650 	ret_reg->s32_min_value = -MAX_ERRNO;
8651 	reg_bounds_sync(ret_reg);
8652 }
8653 
8654 static int
8655 record_func_map(struct bpf_verifier_env *env, struct bpf_call_arg_meta *meta,
8656 		int func_id, int insn_idx)
8657 {
8658 	struct bpf_insn_aux_data *aux = &env->insn_aux_data[insn_idx];
8659 	struct bpf_map *map = meta->map_ptr;
8660 
8661 	if (func_id != BPF_FUNC_tail_call &&
8662 	    func_id != BPF_FUNC_map_lookup_elem &&
8663 	    func_id != BPF_FUNC_map_update_elem &&
8664 	    func_id != BPF_FUNC_map_delete_elem &&
8665 	    func_id != BPF_FUNC_map_push_elem &&
8666 	    func_id != BPF_FUNC_map_pop_elem &&
8667 	    func_id != BPF_FUNC_map_peek_elem &&
8668 	    func_id != BPF_FUNC_for_each_map_elem &&
8669 	    func_id != BPF_FUNC_redirect_map &&
8670 	    func_id != BPF_FUNC_map_lookup_percpu_elem)
8671 		return 0;
8672 
8673 	if (map == NULL) {
8674 		verbose(env, "kernel subsystem misconfigured verifier\n");
8675 		return -EINVAL;
8676 	}
8677 
8678 	/* In case of read-only, some additional restrictions
8679 	 * need to be applied in order to prevent altering the
8680 	 * state of the map from program side.
8681 	 */
8682 	if ((map->map_flags & BPF_F_RDONLY_PROG) &&
8683 	    (func_id == BPF_FUNC_map_delete_elem ||
8684 	     func_id == BPF_FUNC_map_update_elem ||
8685 	     func_id == BPF_FUNC_map_push_elem ||
8686 	     func_id == BPF_FUNC_map_pop_elem)) {
8687 		verbose(env, "write into map forbidden\n");
8688 		return -EACCES;
8689 	}
8690 
8691 	if (!BPF_MAP_PTR(aux->map_ptr_state))
8692 		bpf_map_ptr_store(aux, meta->map_ptr,
8693 				  !meta->map_ptr->bypass_spec_v1);
8694 	else if (BPF_MAP_PTR(aux->map_ptr_state) != meta->map_ptr)
8695 		bpf_map_ptr_store(aux, BPF_MAP_PTR_POISON,
8696 				  !meta->map_ptr->bypass_spec_v1);
8697 	return 0;
8698 }
8699 
8700 static int
8701 record_func_key(struct bpf_verifier_env *env, struct bpf_call_arg_meta *meta,
8702 		int func_id, int insn_idx)
8703 {
8704 	struct bpf_insn_aux_data *aux = &env->insn_aux_data[insn_idx];
8705 	struct bpf_reg_state *regs = cur_regs(env), *reg;
8706 	struct bpf_map *map = meta->map_ptr;
8707 	u64 val, max;
8708 	int err;
8709 
8710 	if (func_id != BPF_FUNC_tail_call)
8711 		return 0;
8712 	if (!map || map->map_type != BPF_MAP_TYPE_PROG_ARRAY) {
8713 		verbose(env, "kernel subsystem misconfigured verifier\n");
8714 		return -EINVAL;
8715 	}
8716 
8717 	reg = &regs[BPF_REG_3];
8718 	val = reg->var_off.value;
8719 	max = map->max_entries;
8720 
8721 	if (!(register_is_const(reg) && val < max)) {
8722 		bpf_map_key_store(aux, BPF_MAP_KEY_POISON);
8723 		return 0;
8724 	}
8725 
8726 	err = mark_chain_precision(env, BPF_REG_3);
8727 	if (err)
8728 		return err;
8729 	if (bpf_map_key_unseen(aux))
8730 		bpf_map_key_store(aux, val);
8731 	else if (!bpf_map_key_poisoned(aux) &&
8732 		  bpf_map_key_immediate(aux) != val)
8733 		bpf_map_key_store(aux, BPF_MAP_KEY_POISON);
8734 	return 0;
8735 }
8736 
8737 static int check_reference_leak(struct bpf_verifier_env *env)
8738 {
8739 	struct bpf_func_state *state = cur_func(env);
8740 	bool refs_lingering = false;
8741 	int i;
8742 
8743 	if (state->frameno && !state->in_callback_fn)
8744 		return 0;
8745 
8746 	for (i = 0; i < state->acquired_refs; i++) {
8747 		if (state->in_callback_fn && state->refs[i].callback_ref != state->frameno)
8748 			continue;
8749 		verbose(env, "Unreleased reference id=%d alloc_insn=%d\n",
8750 			state->refs[i].id, state->refs[i].insn_idx);
8751 		refs_lingering = true;
8752 	}
8753 	return refs_lingering ? -EINVAL : 0;
8754 }
8755 
8756 static int check_bpf_snprintf_call(struct bpf_verifier_env *env,
8757 				   struct bpf_reg_state *regs)
8758 {
8759 	struct bpf_reg_state *fmt_reg = &regs[BPF_REG_3];
8760 	struct bpf_reg_state *data_len_reg = &regs[BPF_REG_5];
8761 	struct bpf_map *fmt_map = fmt_reg->map_ptr;
8762 	struct bpf_bprintf_data data = {};
8763 	int err, fmt_map_off, num_args;
8764 	u64 fmt_addr;
8765 	char *fmt;
8766 
8767 	/* data must be an array of u64 */
8768 	if (data_len_reg->var_off.value % 8)
8769 		return -EINVAL;
8770 	num_args = data_len_reg->var_off.value / 8;
8771 
8772 	/* fmt being ARG_PTR_TO_CONST_STR guarantees that var_off is const
8773 	 * and map_direct_value_addr is set.
8774 	 */
8775 	fmt_map_off = fmt_reg->off + fmt_reg->var_off.value;
8776 	err = fmt_map->ops->map_direct_value_addr(fmt_map, &fmt_addr,
8777 						  fmt_map_off);
8778 	if (err) {
8779 		verbose(env, "verifier bug\n");
8780 		return -EFAULT;
8781 	}
8782 	fmt = (char *)(long)fmt_addr + fmt_map_off;
8783 
8784 	/* We are also guaranteed that fmt+fmt_map_off is NULL terminated, we
8785 	 * can focus on validating the format specifiers.
8786 	 */
8787 	err = bpf_bprintf_prepare(fmt, UINT_MAX, NULL, num_args, &data);
8788 	if (err < 0)
8789 		verbose(env, "Invalid format string\n");
8790 
8791 	return err;
8792 }
8793 
8794 static int check_get_func_ip(struct bpf_verifier_env *env)
8795 {
8796 	enum bpf_prog_type type = resolve_prog_type(env->prog);
8797 	int func_id = BPF_FUNC_get_func_ip;
8798 
8799 	if (type == BPF_PROG_TYPE_TRACING) {
8800 		if (!bpf_prog_has_trampoline(env->prog)) {
8801 			verbose(env, "func %s#%d supported only for fentry/fexit/fmod_ret programs\n",
8802 				func_id_name(func_id), func_id);
8803 			return -ENOTSUPP;
8804 		}
8805 		return 0;
8806 	} else if (type == BPF_PROG_TYPE_KPROBE) {
8807 		return 0;
8808 	}
8809 
8810 	verbose(env, "func %s#%d not supported for program type %d\n",
8811 		func_id_name(func_id), func_id, type);
8812 	return -ENOTSUPP;
8813 }
8814 
8815 static struct bpf_insn_aux_data *cur_aux(struct bpf_verifier_env *env)
8816 {
8817 	return &env->insn_aux_data[env->insn_idx];
8818 }
8819 
8820 static bool loop_flag_is_zero(struct bpf_verifier_env *env)
8821 {
8822 	struct bpf_reg_state *regs = cur_regs(env);
8823 	struct bpf_reg_state *reg = &regs[BPF_REG_4];
8824 	bool reg_is_null = register_is_null(reg);
8825 
8826 	if (reg_is_null)
8827 		mark_chain_precision(env, BPF_REG_4);
8828 
8829 	return reg_is_null;
8830 }
8831 
8832 static void update_loop_inline_state(struct bpf_verifier_env *env, u32 subprogno)
8833 {
8834 	struct bpf_loop_inline_state *state = &cur_aux(env)->loop_inline_state;
8835 
8836 	if (!state->initialized) {
8837 		state->initialized = 1;
8838 		state->fit_for_inline = loop_flag_is_zero(env);
8839 		state->callback_subprogno = subprogno;
8840 		return;
8841 	}
8842 
8843 	if (!state->fit_for_inline)
8844 		return;
8845 
8846 	state->fit_for_inline = (loop_flag_is_zero(env) &&
8847 				 state->callback_subprogno == subprogno);
8848 }
8849 
8850 static int check_helper_call(struct bpf_verifier_env *env, struct bpf_insn *insn,
8851 			     int *insn_idx_p)
8852 {
8853 	enum bpf_prog_type prog_type = resolve_prog_type(env->prog);
8854 	const struct bpf_func_proto *fn = NULL;
8855 	enum bpf_return_type ret_type;
8856 	enum bpf_type_flag ret_flag;
8857 	struct bpf_reg_state *regs;
8858 	struct bpf_call_arg_meta meta;
8859 	int insn_idx = *insn_idx_p;
8860 	bool changes_data;
8861 	int i, err, func_id;
8862 
8863 	/* find function prototype */
8864 	func_id = insn->imm;
8865 	if (func_id < 0 || func_id >= __BPF_FUNC_MAX_ID) {
8866 		verbose(env, "invalid func %s#%d\n", func_id_name(func_id),
8867 			func_id);
8868 		return -EINVAL;
8869 	}
8870 
8871 	if (env->ops->get_func_proto)
8872 		fn = env->ops->get_func_proto(func_id, env->prog);
8873 	if (!fn) {
8874 		verbose(env, "unknown func %s#%d\n", func_id_name(func_id),
8875 			func_id);
8876 		return -EINVAL;
8877 	}
8878 
8879 	/* eBPF programs must be GPL compatible to use GPL-ed functions */
8880 	if (!env->prog->gpl_compatible && fn->gpl_only) {
8881 		verbose(env, "cannot call GPL-restricted function from non-GPL compatible program\n");
8882 		return -EINVAL;
8883 	}
8884 
8885 	if (fn->allowed && !fn->allowed(env->prog)) {
8886 		verbose(env, "helper call is not allowed in probe\n");
8887 		return -EINVAL;
8888 	}
8889 
8890 	if (!env->prog->aux->sleepable && fn->might_sleep) {
8891 		verbose(env, "helper call might sleep in a non-sleepable prog\n");
8892 		return -EINVAL;
8893 	}
8894 
8895 	/* With LD_ABS/IND some JITs save/restore skb from r1. */
8896 	changes_data = bpf_helper_changes_pkt_data(fn->func);
8897 	if (changes_data && fn->arg1_type != ARG_PTR_TO_CTX) {
8898 		verbose(env, "kernel subsystem misconfigured func %s#%d: r1 != ctx\n",
8899 			func_id_name(func_id), func_id);
8900 		return -EINVAL;
8901 	}
8902 
8903 	memset(&meta, 0, sizeof(meta));
8904 	meta.pkt_access = fn->pkt_access;
8905 
8906 	err = check_func_proto(fn, func_id);
8907 	if (err) {
8908 		verbose(env, "kernel subsystem misconfigured func %s#%d\n",
8909 			func_id_name(func_id), func_id);
8910 		return err;
8911 	}
8912 
8913 	if (env->cur_state->active_rcu_lock) {
8914 		if (fn->might_sleep) {
8915 			verbose(env, "sleepable helper %s#%d in rcu_read_lock region\n",
8916 				func_id_name(func_id), func_id);
8917 			return -EINVAL;
8918 		}
8919 
8920 		if (env->prog->aux->sleepable && is_storage_get_function(func_id))
8921 			env->insn_aux_data[insn_idx].storage_get_func_atomic = true;
8922 	}
8923 
8924 	meta.func_id = func_id;
8925 	/* check args */
8926 	for (i = 0; i < MAX_BPF_FUNC_REG_ARGS; i++) {
8927 		err = check_func_arg(env, i, &meta, fn, insn_idx);
8928 		if (err)
8929 			return err;
8930 	}
8931 
8932 	err = record_func_map(env, &meta, func_id, insn_idx);
8933 	if (err)
8934 		return err;
8935 
8936 	err = record_func_key(env, &meta, func_id, insn_idx);
8937 	if (err)
8938 		return err;
8939 
8940 	/* Mark slots with STACK_MISC in case of raw mode, stack offset
8941 	 * is inferred from register state.
8942 	 */
8943 	for (i = 0; i < meta.access_size; i++) {
8944 		err = check_mem_access(env, insn_idx, meta.regno, i, BPF_B,
8945 				       BPF_WRITE, -1, false);
8946 		if (err)
8947 			return err;
8948 	}
8949 
8950 	regs = cur_regs(env);
8951 
8952 	if (meta.release_regno) {
8953 		err = -EINVAL;
8954 		/* This can only be set for PTR_TO_STACK, as CONST_PTR_TO_DYNPTR cannot
8955 		 * be released by any dynptr helper. Hence, unmark_stack_slots_dynptr
8956 		 * is safe to do directly.
8957 		 */
8958 		if (arg_type_is_dynptr(fn->arg_type[meta.release_regno - BPF_REG_1])) {
8959 			if (regs[meta.release_regno].type == CONST_PTR_TO_DYNPTR) {
8960 				verbose(env, "verifier internal error: CONST_PTR_TO_DYNPTR cannot be released\n");
8961 				return -EFAULT;
8962 			}
8963 			err = unmark_stack_slots_dynptr(env, &regs[meta.release_regno]);
8964 		} else if (meta.ref_obj_id) {
8965 			err = release_reference(env, meta.ref_obj_id);
8966 		} else if (register_is_null(&regs[meta.release_regno])) {
8967 			/* meta.ref_obj_id can only be 0 if register that is meant to be
8968 			 * released is NULL, which must be > R0.
8969 			 */
8970 			err = 0;
8971 		}
8972 		if (err) {
8973 			verbose(env, "func %s#%d reference has not been acquired before\n",
8974 				func_id_name(func_id), func_id);
8975 			return err;
8976 		}
8977 	}
8978 
8979 	switch (func_id) {
8980 	case BPF_FUNC_tail_call:
8981 		err = check_reference_leak(env);
8982 		if (err) {
8983 			verbose(env, "tail_call would lead to reference leak\n");
8984 			return err;
8985 		}
8986 		break;
8987 	case BPF_FUNC_get_local_storage:
8988 		/* check that flags argument in get_local_storage(map, flags) is 0,
8989 		 * this is required because get_local_storage() can't return an error.
8990 		 */
8991 		if (!register_is_null(&regs[BPF_REG_2])) {
8992 			verbose(env, "get_local_storage() doesn't support non-zero flags\n");
8993 			return -EINVAL;
8994 		}
8995 		break;
8996 	case BPF_FUNC_for_each_map_elem:
8997 		err = __check_func_call(env, insn, insn_idx_p, meta.subprogno,
8998 					set_map_elem_callback_state);
8999 		break;
9000 	case BPF_FUNC_timer_set_callback:
9001 		err = __check_func_call(env, insn, insn_idx_p, meta.subprogno,
9002 					set_timer_callback_state);
9003 		break;
9004 	case BPF_FUNC_find_vma:
9005 		err = __check_func_call(env, insn, insn_idx_p, meta.subprogno,
9006 					set_find_vma_callback_state);
9007 		break;
9008 	case BPF_FUNC_snprintf:
9009 		err = check_bpf_snprintf_call(env, regs);
9010 		break;
9011 	case BPF_FUNC_loop:
9012 		update_loop_inline_state(env, meta.subprogno);
9013 		err = __check_func_call(env, insn, insn_idx_p, meta.subprogno,
9014 					set_loop_callback_state);
9015 		break;
9016 	case BPF_FUNC_dynptr_from_mem:
9017 		if (regs[BPF_REG_1].type != PTR_TO_MAP_VALUE) {
9018 			verbose(env, "Unsupported reg type %s for bpf_dynptr_from_mem data\n",
9019 				reg_type_str(env, regs[BPF_REG_1].type));
9020 			return -EACCES;
9021 		}
9022 		break;
9023 	case BPF_FUNC_set_retval:
9024 		if (prog_type == BPF_PROG_TYPE_LSM &&
9025 		    env->prog->expected_attach_type == BPF_LSM_CGROUP) {
9026 			if (!env->prog->aux->attach_func_proto->type) {
9027 				/* Make sure programs that attach to void
9028 				 * hooks don't try to modify return value.
9029 				 */
9030 				verbose(env, "BPF_LSM_CGROUP that attach to void LSM hooks can't modify return value!\n");
9031 				return -EINVAL;
9032 			}
9033 		}
9034 		break;
9035 	case BPF_FUNC_dynptr_data:
9036 	{
9037 		struct bpf_reg_state *reg;
9038 		int id, ref_obj_id;
9039 
9040 		reg = get_dynptr_arg_reg(env, fn, regs);
9041 		if (!reg)
9042 			return -EFAULT;
9043 
9044 
9045 		if (meta.dynptr_id) {
9046 			verbose(env, "verifier internal error: meta.dynptr_id already set\n");
9047 			return -EFAULT;
9048 		}
9049 		if (meta.ref_obj_id) {
9050 			verbose(env, "verifier internal error: meta.ref_obj_id already set\n");
9051 			return -EFAULT;
9052 		}
9053 
9054 		id = dynptr_id(env, reg);
9055 		if (id < 0) {
9056 			verbose(env, "verifier internal error: failed to obtain dynptr id\n");
9057 			return id;
9058 		}
9059 
9060 		ref_obj_id = dynptr_ref_obj_id(env, reg);
9061 		if (ref_obj_id < 0) {
9062 			verbose(env, "verifier internal error: failed to obtain dynptr ref_obj_id\n");
9063 			return ref_obj_id;
9064 		}
9065 
9066 		meta.dynptr_id = id;
9067 		meta.ref_obj_id = ref_obj_id;
9068 
9069 		break;
9070 	}
9071 	case BPF_FUNC_dynptr_write:
9072 	{
9073 		enum bpf_dynptr_type dynptr_type;
9074 		struct bpf_reg_state *reg;
9075 
9076 		reg = get_dynptr_arg_reg(env, fn, regs);
9077 		if (!reg)
9078 			return -EFAULT;
9079 
9080 		dynptr_type = dynptr_get_type(env, reg);
9081 		if (dynptr_type == BPF_DYNPTR_TYPE_INVALID)
9082 			return -EFAULT;
9083 
9084 		if (dynptr_type == BPF_DYNPTR_TYPE_SKB)
9085 			/* this will trigger clear_all_pkt_pointers(), which will
9086 			 * invalidate all dynptr slices associated with the skb
9087 			 */
9088 			changes_data = true;
9089 
9090 		break;
9091 	}
9092 	case BPF_FUNC_user_ringbuf_drain:
9093 		err = __check_func_call(env, insn, insn_idx_p, meta.subprogno,
9094 					set_user_ringbuf_callback_state);
9095 		break;
9096 	}
9097 
9098 	if (err)
9099 		return err;
9100 
9101 	/* reset caller saved regs */
9102 	for (i = 0; i < CALLER_SAVED_REGS; i++) {
9103 		mark_reg_not_init(env, regs, caller_saved[i]);
9104 		check_reg_arg(env, caller_saved[i], DST_OP_NO_MARK);
9105 	}
9106 
9107 	/* helper call returns 64-bit value. */
9108 	regs[BPF_REG_0].subreg_def = DEF_NOT_SUBREG;
9109 
9110 	/* update return register (already marked as written above) */
9111 	ret_type = fn->ret_type;
9112 	ret_flag = type_flag(ret_type);
9113 
9114 	switch (base_type(ret_type)) {
9115 	case RET_INTEGER:
9116 		/* sets type to SCALAR_VALUE */
9117 		mark_reg_unknown(env, regs, BPF_REG_0);
9118 		break;
9119 	case RET_VOID:
9120 		regs[BPF_REG_0].type = NOT_INIT;
9121 		break;
9122 	case RET_PTR_TO_MAP_VALUE:
9123 		/* There is no offset yet applied, variable or fixed */
9124 		mark_reg_known_zero(env, regs, BPF_REG_0);
9125 		/* remember map_ptr, so that check_map_access()
9126 		 * can check 'value_size' boundary of memory access
9127 		 * to map element returned from bpf_map_lookup_elem()
9128 		 */
9129 		if (meta.map_ptr == NULL) {
9130 			verbose(env,
9131 				"kernel subsystem misconfigured verifier\n");
9132 			return -EINVAL;
9133 		}
9134 		regs[BPF_REG_0].map_ptr = meta.map_ptr;
9135 		regs[BPF_REG_0].map_uid = meta.map_uid;
9136 		regs[BPF_REG_0].type = PTR_TO_MAP_VALUE | ret_flag;
9137 		if (!type_may_be_null(ret_type) &&
9138 		    btf_record_has_field(meta.map_ptr->record, BPF_SPIN_LOCK)) {
9139 			regs[BPF_REG_0].id = ++env->id_gen;
9140 		}
9141 		break;
9142 	case RET_PTR_TO_SOCKET:
9143 		mark_reg_known_zero(env, regs, BPF_REG_0);
9144 		regs[BPF_REG_0].type = PTR_TO_SOCKET | ret_flag;
9145 		break;
9146 	case RET_PTR_TO_SOCK_COMMON:
9147 		mark_reg_known_zero(env, regs, BPF_REG_0);
9148 		regs[BPF_REG_0].type = PTR_TO_SOCK_COMMON | ret_flag;
9149 		break;
9150 	case RET_PTR_TO_TCP_SOCK:
9151 		mark_reg_known_zero(env, regs, BPF_REG_0);
9152 		regs[BPF_REG_0].type = PTR_TO_TCP_SOCK | ret_flag;
9153 		break;
9154 	case RET_PTR_TO_MEM:
9155 		mark_reg_known_zero(env, regs, BPF_REG_0);
9156 		regs[BPF_REG_0].type = PTR_TO_MEM | ret_flag;
9157 		regs[BPF_REG_0].mem_size = meta.mem_size;
9158 		break;
9159 	case RET_PTR_TO_MEM_OR_BTF_ID:
9160 	{
9161 		const struct btf_type *t;
9162 
9163 		mark_reg_known_zero(env, regs, BPF_REG_0);
9164 		t = btf_type_skip_modifiers(meta.ret_btf, meta.ret_btf_id, NULL);
9165 		if (!btf_type_is_struct(t)) {
9166 			u32 tsize;
9167 			const struct btf_type *ret;
9168 			const char *tname;
9169 
9170 			/* resolve the type size of ksym. */
9171 			ret = btf_resolve_size(meta.ret_btf, t, &tsize);
9172 			if (IS_ERR(ret)) {
9173 				tname = btf_name_by_offset(meta.ret_btf, t->name_off);
9174 				verbose(env, "unable to resolve the size of type '%s': %ld\n",
9175 					tname, PTR_ERR(ret));
9176 				return -EINVAL;
9177 			}
9178 			regs[BPF_REG_0].type = PTR_TO_MEM | ret_flag;
9179 			regs[BPF_REG_0].mem_size = tsize;
9180 		} else {
9181 			/* MEM_RDONLY may be carried from ret_flag, but it
9182 			 * doesn't apply on PTR_TO_BTF_ID. Fold it, otherwise
9183 			 * it will confuse the check of PTR_TO_BTF_ID in
9184 			 * check_mem_access().
9185 			 */
9186 			ret_flag &= ~MEM_RDONLY;
9187 
9188 			regs[BPF_REG_0].type = PTR_TO_BTF_ID | ret_flag;
9189 			regs[BPF_REG_0].btf = meta.ret_btf;
9190 			regs[BPF_REG_0].btf_id = meta.ret_btf_id;
9191 		}
9192 		break;
9193 	}
9194 	case RET_PTR_TO_BTF_ID:
9195 	{
9196 		struct btf *ret_btf;
9197 		int ret_btf_id;
9198 
9199 		mark_reg_known_zero(env, regs, BPF_REG_0);
9200 		regs[BPF_REG_0].type = PTR_TO_BTF_ID | ret_flag;
9201 		if (func_id == BPF_FUNC_kptr_xchg) {
9202 			ret_btf = meta.kptr_field->kptr.btf;
9203 			ret_btf_id = meta.kptr_field->kptr.btf_id;
9204 			if (!btf_is_kernel(ret_btf))
9205 				regs[BPF_REG_0].type |= MEM_ALLOC;
9206 		} else {
9207 			if (fn->ret_btf_id == BPF_PTR_POISON) {
9208 				verbose(env, "verifier internal error:");
9209 				verbose(env, "func %s has non-overwritten BPF_PTR_POISON return type\n",
9210 					func_id_name(func_id));
9211 				return -EINVAL;
9212 			}
9213 			ret_btf = btf_vmlinux;
9214 			ret_btf_id = *fn->ret_btf_id;
9215 		}
9216 		if (ret_btf_id == 0) {
9217 			verbose(env, "invalid return type %u of func %s#%d\n",
9218 				base_type(ret_type), func_id_name(func_id),
9219 				func_id);
9220 			return -EINVAL;
9221 		}
9222 		regs[BPF_REG_0].btf = ret_btf;
9223 		regs[BPF_REG_0].btf_id = ret_btf_id;
9224 		break;
9225 	}
9226 	default:
9227 		verbose(env, "unknown return type %u of func %s#%d\n",
9228 			base_type(ret_type), func_id_name(func_id), func_id);
9229 		return -EINVAL;
9230 	}
9231 
9232 	if (type_may_be_null(regs[BPF_REG_0].type))
9233 		regs[BPF_REG_0].id = ++env->id_gen;
9234 
9235 	if (helper_multiple_ref_obj_use(func_id, meta.map_ptr)) {
9236 		verbose(env, "verifier internal error: func %s#%d sets ref_obj_id more than once\n",
9237 			func_id_name(func_id), func_id);
9238 		return -EFAULT;
9239 	}
9240 
9241 	if (is_dynptr_ref_function(func_id))
9242 		regs[BPF_REG_0].dynptr_id = meta.dynptr_id;
9243 
9244 	if (is_ptr_cast_function(func_id) || is_dynptr_ref_function(func_id)) {
9245 		/* For release_reference() */
9246 		regs[BPF_REG_0].ref_obj_id = meta.ref_obj_id;
9247 	} else if (is_acquire_function(func_id, meta.map_ptr)) {
9248 		int id = acquire_reference_state(env, insn_idx);
9249 
9250 		if (id < 0)
9251 			return id;
9252 		/* For mark_ptr_or_null_reg() */
9253 		regs[BPF_REG_0].id = id;
9254 		/* For release_reference() */
9255 		regs[BPF_REG_0].ref_obj_id = id;
9256 	}
9257 
9258 	do_refine_retval_range(regs, fn->ret_type, func_id, &meta);
9259 
9260 	err = check_map_func_compatibility(env, meta.map_ptr, func_id);
9261 	if (err)
9262 		return err;
9263 
9264 	if ((func_id == BPF_FUNC_get_stack ||
9265 	     func_id == BPF_FUNC_get_task_stack) &&
9266 	    !env->prog->has_callchain_buf) {
9267 		const char *err_str;
9268 
9269 #ifdef CONFIG_PERF_EVENTS
9270 		err = get_callchain_buffers(sysctl_perf_event_max_stack);
9271 		err_str = "cannot get callchain buffer for func %s#%d\n";
9272 #else
9273 		err = -ENOTSUPP;
9274 		err_str = "func %s#%d not supported without CONFIG_PERF_EVENTS\n";
9275 #endif
9276 		if (err) {
9277 			verbose(env, err_str, func_id_name(func_id), func_id);
9278 			return err;
9279 		}
9280 
9281 		env->prog->has_callchain_buf = true;
9282 	}
9283 
9284 	if (func_id == BPF_FUNC_get_stackid || func_id == BPF_FUNC_get_stack)
9285 		env->prog->call_get_stack = true;
9286 
9287 	if (func_id == BPF_FUNC_get_func_ip) {
9288 		if (check_get_func_ip(env))
9289 			return -ENOTSUPP;
9290 		env->prog->call_get_func_ip = true;
9291 	}
9292 
9293 	if (changes_data)
9294 		clear_all_pkt_pointers(env);
9295 	return 0;
9296 }
9297 
9298 /* mark_btf_func_reg_size() is used when the reg size is determined by
9299  * the BTF func_proto's return value size and argument.
9300  */
9301 static void mark_btf_func_reg_size(struct bpf_verifier_env *env, u32 regno,
9302 				   size_t reg_size)
9303 {
9304 	struct bpf_reg_state *reg = &cur_regs(env)[regno];
9305 
9306 	if (regno == BPF_REG_0) {
9307 		/* Function return value */
9308 		reg->live |= REG_LIVE_WRITTEN;
9309 		reg->subreg_def = reg_size == sizeof(u64) ?
9310 			DEF_NOT_SUBREG : env->insn_idx + 1;
9311 	} else {
9312 		/* Function argument */
9313 		if (reg_size == sizeof(u64)) {
9314 			mark_insn_zext(env, reg);
9315 			mark_reg_read(env, reg, reg->parent, REG_LIVE_READ64);
9316 		} else {
9317 			mark_reg_read(env, reg, reg->parent, REG_LIVE_READ32);
9318 		}
9319 	}
9320 }
9321 
9322 static bool is_kfunc_acquire(struct bpf_kfunc_call_arg_meta *meta)
9323 {
9324 	return meta->kfunc_flags & KF_ACQUIRE;
9325 }
9326 
9327 static bool is_kfunc_ret_null(struct bpf_kfunc_call_arg_meta *meta)
9328 {
9329 	return meta->kfunc_flags & KF_RET_NULL;
9330 }
9331 
9332 static bool is_kfunc_release(struct bpf_kfunc_call_arg_meta *meta)
9333 {
9334 	return meta->kfunc_flags & KF_RELEASE;
9335 }
9336 
9337 static bool is_kfunc_trusted_args(struct bpf_kfunc_call_arg_meta *meta)
9338 {
9339 	return (meta->kfunc_flags & KF_TRUSTED_ARGS) || is_kfunc_release(meta);
9340 }
9341 
9342 static bool is_kfunc_sleepable(struct bpf_kfunc_call_arg_meta *meta)
9343 {
9344 	return meta->kfunc_flags & KF_SLEEPABLE;
9345 }
9346 
9347 static bool is_kfunc_destructive(struct bpf_kfunc_call_arg_meta *meta)
9348 {
9349 	return meta->kfunc_flags & KF_DESTRUCTIVE;
9350 }
9351 
9352 static bool is_kfunc_rcu(struct bpf_kfunc_call_arg_meta *meta)
9353 {
9354 	return meta->kfunc_flags & KF_RCU;
9355 }
9356 
9357 static bool __kfunc_param_match_suffix(const struct btf *btf,
9358 				       const struct btf_param *arg,
9359 				       const char *suffix)
9360 {
9361 	int suffix_len = strlen(suffix), len;
9362 	const char *param_name;
9363 
9364 	/* In the future, this can be ported to use BTF tagging */
9365 	param_name = btf_name_by_offset(btf, arg->name_off);
9366 	if (str_is_empty(param_name))
9367 		return false;
9368 	len = strlen(param_name);
9369 	if (len < suffix_len)
9370 		return false;
9371 	param_name += len - suffix_len;
9372 	return !strncmp(param_name, suffix, suffix_len);
9373 }
9374 
9375 static bool is_kfunc_arg_mem_size(const struct btf *btf,
9376 				  const struct btf_param *arg,
9377 				  const struct bpf_reg_state *reg)
9378 {
9379 	const struct btf_type *t;
9380 
9381 	t = btf_type_skip_modifiers(btf, arg->type, NULL);
9382 	if (!btf_type_is_scalar(t) || reg->type != SCALAR_VALUE)
9383 		return false;
9384 
9385 	return __kfunc_param_match_suffix(btf, arg, "__sz");
9386 }
9387 
9388 static bool is_kfunc_arg_const_mem_size(const struct btf *btf,
9389 					const struct btf_param *arg,
9390 					const struct bpf_reg_state *reg)
9391 {
9392 	const struct btf_type *t;
9393 
9394 	t = btf_type_skip_modifiers(btf, arg->type, NULL);
9395 	if (!btf_type_is_scalar(t) || reg->type != SCALAR_VALUE)
9396 		return false;
9397 
9398 	return __kfunc_param_match_suffix(btf, arg, "__szk");
9399 }
9400 
9401 static bool is_kfunc_arg_constant(const struct btf *btf, const struct btf_param *arg)
9402 {
9403 	return __kfunc_param_match_suffix(btf, arg, "__k");
9404 }
9405 
9406 static bool is_kfunc_arg_ignore(const struct btf *btf, const struct btf_param *arg)
9407 {
9408 	return __kfunc_param_match_suffix(btf, arg, "__ign");
9409 }
9410 
9411 static bool is_kfunc_arg_alloc_obj(const struct btf *btf, const struct btf_param *arg)
9412 {
9413 	return __kfunc_param_match_suffix(btf, arg, "__alloc");
9414 }
9415 
9416 static bool is_kfunc_arg_uninit(const struct btf *btf, const struct btf_param *arg)
9417 {
9418 	return __kfunc_param_match_suffix(btf, arg, "__uninit");
9419 }
9420 
9421 static bool is_kfunc_arg_refcounted_kptr(const struct btf *btf, const struct btf_param *arg)
9422 {
9423 	return __kfunc_param_match_suffix(btf, arg, "__refcounted_kptr");
9424 }
9425 
9426 static bool is_kfunc_arg_scalar_with_name(const struct btf *btf,
9427 					  const struct btf_param *arg,
9428 					  const char *name)
9429 {
9430 	int len, target_len = strlen(name);
9431 	const char *param_name;
9432 
9433 	param_name = btf_name_by_offset(btf, arg->name_off);
9434 	if (str_is_empty(param_name))
9435 		return false;
9436 	len = strlen(param_name);
9437 	if (len != target_len)
9438 		return false;
9439 	if (strcmp(param_name, name))
9440 		return false;
9441 
9442 	return true;
9443 }
9444 
9445 enum {
9446 	KF_ARG_DYNPTR_ID,
9447 	KF_ARG_LIST_HEAD_ID,
9448 	KF_ARG_LIST_NODE_ID,
9449 	KF_ARG_RB_ROOT_ID,
9450 	KF_ARG_RB_NODE_ID,
9451 };
9452 
9453 BTF_ID_LIST(kf_arg_btf_ids)
9454 BTF_ID(struct, bpf_dynptr_kern)
9455 BTF_ID(struct, bpf_list_head)
9456 BTF_ID(struct, bpf_list_node)
9457 BTF_ID(struct, bpf_rb_root)
9458 BTF_ID(struct, bpf_rb_node)
9459 
9460 static bool __is_kfunc_ptr_arg_type(const struct btf *btf,
9461 				    const struct btf_param *arg, int type)
9462 {
9463 	const struct btf_type *t;
9464 	u32 res_id;
9465 
9466 	t = btf_type_skip_modifiers(btf, arg->type, NULL);
9467 	if (!t)
9468 		return false;
9469 	if (!btf_type_is_ptr(t))
9470 		return false;
9471 	t = btf_type_skip_modifiers(btf, t->type, &res_id);
9472 	if (!t)
9473 		return false;
9474 	return btf_types_are_same(btf, res_id, btf_vmlinux, kf_arg_btf_ids[type]);
9475 }
9476 
9477 static bool is_kfunc_arg_dynptr(const struct btf *btf, const struct btf_param *arg)
9478 {
9479 	return __is_kfunc_ptr_arg_type(btf, arg, KF_ARG_DYNPTR_ID);
9480 }
9481 
9482 static bool is_kfunc_arg_list_head(const struct btf *btf, const struct btf_param *arg)
9483 {
9484 	return __is_kfunc_ptr_arg_type(btf, arg, KF_ARG_LIST_HEAD_ID);
9485 }
9486 
9487 static bool is_kfunc_arg_list_node(const struct btf *btf, const struct btf_param *arg)
9488 {
9489 	return __is_kfunc_ptr_arg_type(btf, arg, KF_ARG_LIST_NODE_ID);
9490 }
9491 
9492 static bool is_kfunc_arg_rbtree_root(const struct btf *btf, const struct btf_param *arg)
9493 {
9494 	return __is_kfunc_ptr_arg_type(btf, arg, KF_ARG_RB_ROOT_ID);
9495 }
9496 
9497 static bool is_kfunc_arg_rbtree_node(const struct btf *btf, const struct btf_param *arg)
9498 {
9499 	return __is_kfunc_ptr_arg_type(btf, arg, KF_ARG_RB_NODE_ID);
9500 }
9501 
9502 static bool is_kfunc_arg_callback(struct bpf_verifier_env *env, const struct btf *btf,
9503 				  const struct btf_param *arg)
9504 {
9505 	const struct btf_type *t;
9506 
9507 	t = btf_type_resolve_func_ptr(btf, arg->type, NULL);
9508 	if (!t)
9509 		return false;
9510 
9511 	return true;
9512 }
9513 
9514 /* Returns true if struct is composed of scalars, 4 levels of nesting allowed */
9515 static bool __btf_type_is_scalar_struct(struct bpf_verifier_env *env,
9516 					const struct btf *btf,
9517 					const struct btf_type *t, int rec)
9518 {
9519 	const struct btf_type *member_type;
9520 	const struct btf_member *member;
9521 	u32 i;
9522 
9523 	if (!btf_type_is_struct(t))
9524 		return false;
9525 
9526 	for_each_member(i, t, member) {
9527 		const struct btf_array *array;
9528 
9529 		member_type = btf_type_skip_modifiers(btf, member->type, NULL);
9530 		if (btf_type_is_struct(member_type)) {
9531 			if (rec >= 3) {
9532 				verbose(env, "max struct nesting depth exceeded\n");
9533 				return false;
9534 			}
9535 			if (!__btf_type_is_scalar_struct(env, btf, member_type, rec + 1))
9536 				return false;
9537 			continue;
9538 		}
9539 		if (btf_type_is_array(member_type)) {
9540 			array = btf_array(member_type);
9541 			if (!array->nelems)
9542 				return false;
9543 			member_type = btf_type_skip_modifiers(btf, array->type, NULL);
9544 			if (!btf_type_is_scalar(member_type))
9545 				return false;
9546 			continue;
9547 		}
9548 		if (!btf_type_is_scalar(member_type))
9549 			return false;
9550 	}
9551 	return true;
9552 }
9553 
9554 
9555 static u32 *reg2btf_ids[__BPF_REG_TYPE_MAX] = {
9556 #ifdef CONFIG_NET
9557 	[PTR_TO_SOCKET] = &btf_sock_ids[BTF_SOCK_TYPE_SOCK],
9558 	[PTR_TO_SOCK_COMMON] = &btf_sock_ids[BTF_SOCK_TYPE_SOCK_COMMON],
9559 	[PTR_TO_TCP_SOCK] = &btf_sock_ids[BTF_SOCK_TYPE_TCP],
9560 #endif
9561 };
9562 
9563 enum kfunc_ptr_arg_type {
9564 	KF_ARG_PTR_TO_CTX,
9565 	KF_ARG_PTR_TO_ALLOC_BTF_ID,    /* Allocated object */
9566 	KF_ARG_PTR_TO_REFCOUNTED_KPTR, /* Refcounted local kptr */
9567 	KF_ARG_PTR_TO_DYNPTR,
9568 	KF_ARG_PTR_TO_ITER,
9569 	KF_ARG_PTR_TO_LIST_HEAD,
9570 	KF_ARG_PTR_TO_LIST_NODE,
9571 	KF_ARG_PTR_TO_BTF_ID,	       /* Also covers reg2btf_ids conversions */
9572 	KF_ARG_PTR_TO_MEM,
9573 	KF_ARG_PTR_TO_MEM_SIZE,	       /* Size derived from next argument, skip it */
9574 	KF_ARG_PTR_TO_CALLBACK,
9575 	KF_ARG_PTR_TO_RB_ROOT,
9576 	KF_ARG_PTR_TO_RB_NODE,
9577 };
9578 
9579 enum special_kfunc_type {
9580 	KF_bpf_obj_new_impl,
9581 	KF_bpf_obj_drop_impl,
9582 	KF_bpf_refcount_acquire_impl,
9583 	KF_bpf_list_push_front_impl,
9584 	KF_bpf_list_push_back_impl,
9585 	KF_bpf_list_pop_front,
9586 	KF_bpf_list_pop_back,
9587 	KF_bpf_cast_to_kern_ctx,
9588 	KF_bpf_rdonly_cast,
9589 	KF_bpf_rcu_read_lock,
9590 	KF_bpf_rcu_read_unlock,
9591 	KF_bpf_rbtree_remove,
9592 	KF_bpf_rbtree_add_impl,
9593 	KF_bpf_rbtree_first,
9594 	KF_bpf_dynptr_from_skb,
9595 	KF_bpf_dynptr_from_xdp,
9596 	KF_bpf_dynptr_slice,
9597 	KF_bpf_dynptr_slice_rdwr,
9598 };
9599 
9600 BTF_SET_START(special_kfunc_set)
9601 BTF_ID(func, bpf_obj_new_impl)
9602 BTF_ID(func, bpf_obj_drop_impl)
9603 BTF_ID(func, bpf_refcount_acquire_impl)
9604 BTF_ID(func, bpf_list_push_front_impl)
9605 BTF_ID(func, bpf_list_push_back_impl)
9606 BTF_ID(func, bpf_list_pop_front)
9607 BTF_ID(func, bpf_list_pop_back)
9608 BTF_ID(func, bpf_cast_to_kern_ctx)
9609 BTF_ID(func, bpf_rdonly_cast)
9610 BTF_ID(func, bpf_rbtree_remove)
9611 BTF_ID(func, bpf_rbtree_add_impl)
9612 BTF_ID(func, bpf_rbtree_first)
9613 BTF_ID(func, bpf_dynptr_from_skb)
9614 BTF_ID(func, bpf_dynptr_from_xdp)
9615 BTF_ID(func, bpf_dynptr_slice)
9616 BTF_ID(func, bpf_dynptr_slice_rdwr)
9617 BTF_SET_END(special_kfunc_set)
9618 
9619 BTF_ID_LIST(special_kfunc_list)
9620 BTF_ID(func, bpf_obj_new_impl)
9621 BTF_ID(func, bpf_obj_drop_impl)
9622 BTF_ID(func, bpf_refcount_acquire_impl)
9623 BTF_ID(func, bpf_list_push_front_impl)
9624 BTF_ID(func, bpf_list_push_back_impl)
9625 BTF_ID(func, bpf_list_pop_front)
9626 BTF_ID(func, bpf_list_pop_back)
9627 BTF_ID(func, bpf_cast_to_kern_ctx)
9628 BTF_ID(func, bpf_rdonly_cast)
9629 BTF_ID(func, bpf_rcu_read_lock)
9630 BTF_ID(func, bpf_rcu_read_unlock)
9631 BTF_ID(func, bpf_rbtree_remove)
9632 BTF_ID(func, bpf_rbtree_add_impl)
9633 BTF_ID(func, bpf_rbtree_first)
9634 BTF_ID(func, bpf_dynptr_from_skb)
9635 BTF_ID(func, bpf_dynptr_from_xdp)
9636 BTF_ID(func, bpf_dynptr_slice)
9637 BTF_ID(func, bpf_dynptr_slice_rdwr)
9638 
9639 static bool is_kfunc_bpf_rcu_read_lock(struct bpf_kfunc_call_arg_meta *meta)
9640 {
9641 	return meta->func_id == special_kfunc_list[KF_bpf_rcu_read_lock];
9642 }
9643 
9644 static bool is_kfunc_bpf_rcu_read_unlock(struct bpf_kfunc_call_arg_meta *meta)
9645 {
9646 	return meta->func_id == special_kfunc_list[KF_bpf_rcu_read_unlock];
9647 }
9648 
9649 static enum kfunc_ptr_arg_type
9650 get_kfunc_ptr_arg_type(struct bpf_verifier_env *env,
9651 		       struct bpf_kfunc_call_arg_meta *meta,
9652 		       const struct btf_type *t, const struct btf_type *ref_t,
9653 		       const char *ref_tname, const struct btf_param *args,
9654 		       int argno, int nargs)
9655 {
9656 	u32 regno = argno + 1;
9657 	struct bpf_reg_state *regs = cur_regs(env);
9658 	struct bpf_reg_state *reg = &regs[regno];
9659 	bool arg_mem_size = false;
9660 
9661 	if (meta->func_id == special_kfunc_list[KF_bpf_cast_to_kern_ctx])
9662 		return KF_ARG_PTR_TO_CTX;
9663 
9664 	/* In this function, we verify the kfunc's BTF as per the argument type,
9665 	 * leaving the rest of the verification with respect to the register
9666 	 * type to our caller. When a set of conditions hold in the BTF type of
9667 	 * arguments, we resolve it to a known kfunc_ptr_arg_type.
9668 	 */
9669 	if (btf_get_prog_ctx_type(&env->log, meta->btf, t, resolve_prog_type(env->prog), argno))
9670 		return KF_ARG_PTR_TO_CTX;
9671 
9672 	if (is_kfunc_arg_alloc_obj(meta->btf, &args[argno]))
9673 		return KF_ARG_PTR_TO_ALLOC_BTF_ID;
9674 
9675 	if (is_kfunc_arg_refcounted_kptr(meta->btf, &args[argno]))
9676 		return KF_ARG_PTR_TO_REFCOUNTED_KPTR;
9677 
9678 	if (is_kfunc_arg_dynptr(meta->btf, &args[argno]))
9679 		return KF_ARG_PTR_TO_DYNPTR;
9680 
9681 	if (is_kfunc_arg_iter(meta, argno))
9682 		return KF_ARG_PTR_TO_ITER;
9683 
9684 	if (is_kfunc_arg_list_head(meta->btf, &args[argno]))
9685 		return KF_ARG_PTR_TO_LIST_HEAD;
9686 
9687 	if (is_kfunc_arg_list_node(meta->btf, &args[argno]))
9688 		return KF_ARG_PTR_TO_LIST_NODE;
9689 
9690 	if (is_kfunc_arg_rbtree_root(meta->btf, &args[argno]))
9691 		return KF_ARG_PTR_TO_RB_ROOT;
9692 
9693 	if (is_kfunc_arg_rbtree_node(meta->btf, &args[argno]))
9694 		return KF_ARG_PTR_TO_RB_NODE;
9695 
9696 	if ((base_type(reg->type) == PTR_TO_BTF_ID || reg2btf_ids[base_type(reg->type)])) {
9697 		if (!btf_type_is_struct(ref_t)) {
9698 			verbose(env, "kernel function %s args#%d pointer type %s %s is not supported\n",
9699 				meta->func_name, argno, btf_type_str(ref_t), ref_tname);
9700 			return -EINVAL;
9701 		}
9702 		return KF_ARG_PTR_TO_BTF_ID;
9703 	}
9704 
9705 	if (is_kfunc_arg_callback(env, meta->btf, &args[argno]))
9706 		return KF_ARG_PTR_TO_CALLBACK;
9707 
9708 
9709 	if (argno + 1 < nargs &&
9710 	    (is_kfunc_arg_mem_size(meta->btf, &args[argno + 1], &regs[regno + 1]) ||
9711 	     is_kfunc_arg_const_mem_size(meta->btf, &args[argno + 1], &regs[regno + 1])))
9712 		arg_mem_size = true;
9713 
9714 	/* This is the catch all argument type of register types supported by
9715 	 * check_helper_mem_access. However, we only allow when argument type is
9716 	 * pointer to scalar, or struct composed (recursively) of scalars. When
9717 	 * arg_mem_size is true, the pointer can be void *.
9718 	 */
9719 	if (!btf_type_is_scalar(ref_t) && !__btf_type_is_scalar_struct(env, meta->btf, ref_t, 0) &&
9720 	    (arg_mem_size ? !btf_type_is_void(ref_t) : 1)) {
9721 		verbose(env, "arg#%d pointer type %s %s must point to %sscalar, or struct with scalar\n",
9722 			argno, btf_type_str(ref_t), ref_tname, arg_mem_size ? "void, " : "");
9723 		return -EINVAL;
9724 	}
9725 	return arg_mem_size ? KF_ARG_PTR_TO_MEM_SIZE : KF_ARG_PTR_TO_MEM;
9726 }
9727 
9728 static int process_kf_arg_ptr_to_btf_id(struct bpf_verifier_env *env,
9729 					struct bpf_reg_state *reg,
9730 					const struct btf_type *ref_t,
9731 					const char *ref_tname, u32 ref_id,
9732 					struct bpf_kfunc_call_arg_meta *meta,
9733 					int argno)
9734 {
9735 	const struct btf_type *reg_ref_t;
9736 	bool strict_type_match = false;
9737 	const struct btf *reg_btf;
9738 	const char *reg_ref_tname;
9739 	u32 reg_ref_id;
9740 
9741 	if (base_type(reg->type) == PTR_TO_BTF_ID) {
9742 		reg_btf = reg->btf;
9743 		reg_ref_id = reg->btf_id;
9744 	} else {
9745 		reg_btf = btf_vmlinux;
9746 		reg_ref_id = *reg2btf_ids[base_type(reg->type)];
9747 	}
9748 
9749 	/* Enforce strict type matching for calls to kfuncs that are acquiring
9750 	 * or releasing a reference, or are no-cast aliases. We do _not_
9751 	 * enforce strict matching for plain KF_TRUSTED_ARGS kfuncs by default,
9752 	 * as we want to enable BPF programs to pass types that are bitwise
9753 	 * equivalent without forcing them to explicitly cast with something
9754 	 * like bpf_cast_to_kern_ctx().
9755 	 *
9756 	 * For example, say we had a type like the following:
9757 	 *
9758 	 * struct bpf_cpumask {
9759 	 *	cpumask_t cpumask;
9760 	 *	refcount_t usage;
9761 	 * };
9762 	 *
9763 	 * Note that as specified in <linux/cpumask.h>, cpumask_t is typedef'ed
9764 	 * to a struct cpumask, so it would be safe to pass a struct
9765 	 * bpf_cpumask * to a kfunc expecting a struct cpumask *.
9766 	 *
9767 	 * The philosophy here is similar to how we allow scalars of different
9768 	 * types to be passed to kfuncs as long as the size is the same. The
9769 	 * only difference here is that we're simply allowing
9770 	 * btf_struct_ids_match() to walk the struct at the 0th offset, and
9771 	 * resolve types.
9772 	 */
9773 	if (is_kfunc_acquire(meta) ||
9774 	    (is_kfunc_release(meta) && reg->ref_obj_id) ||
9775 	    btf_type_ids_nocast_alias(&env->log, reg_btf, reg_ref_id, meta->btf, ref_id))
9776 		strict_type_match = true;
9777 
9778 	WARN_ON_ONCE(is_kfunc_trusted_args(meta) && reg->off);
9779 
9780 	reg_ref_t = btf_type_skip_modifiers(reg_btf, reg_ref_id, &reg_ref_id);
9781 	reg_ref_tname = btf_name_by_offset(reg_btf, reg_ref_t->name_off);
9782 	if (!btf_struct_ids_match(&env->log, reg_btf, reg_ref_id, reg->off, meta->btf, ref_id, strict_type_match)) {
9783 		verbose(env, "kernel function %s args#%d expected pointer to %s %s but R%d has a pointer to %s %s\n",
9784 			meta->func_name, argno, btf_type_str(ref_t), ref_tname, argno + 1,
9785 			btf_type_str(reg_ref_t), reg_ref_tname);
9786 		return -EINVAL;
9787 	}
9788 	return 0;
9789 }
9790 
9791 static int ref_set_non_owning(struct bpf_verifier_env *env, struct bpf_reg_state *reg)
9792 {
9793 	struct bpf_verifier_state *state = env->cur_state;
9794 
9795 	if (!state->active_lock.ptr) {
9796 		verbose(env, "verifier internal error: ref_set_non_owning w/o active lock\n");
9797 		return -EFAULT;
9798 	}
9799 
9800 	if (type_flag(reg->type) & NON_OWN_REF) {
9801 		verbose(env, "verifier internal error: NON_OWN_REF already set\n");
9802 		return -EFAULT;
9803 	}
9804 
9805 	reg->type |= NON_OWN_REF;
9806 	return 0;
9807 }
9808 
9809 static int ref_convert_owning_non_owning(struct bpf_verifier_env *env, u32 ref_obj_id)
9810 {
9811 	struct bpf_func_state *state, *unused;
9812 	struct bpf_reg_state *reg;
9813 	int i;
9814 
9815 	state = cur_func(env);
9816 
9817 	if (!ref_obj_id) {
9818 		verbose(env, "verifier internal error: ref_obj_id is zero for "
9819 			     "owning -> non-owning conversion\n");
9820 		return -EFAULT;
9821 	}
9822 
9823 	for (i = 0; i < state->acquired_refs; i++) {
9824 		if (state->refs[i].id != ref_obj_id)
9825 			continue;
9826 
9827 		/* Clear ref_obj_id here so release_reference doesn't clobber
9828 		 * the whole reg
9829 		 */
9830 		bpf_for_each_reg_in_vstate(env->cur_state, unused, reg, ({
9831 			if (reg->ref_obj_id == ref_obj_id) {
9832 				reg->ref_obj_id = 0;
9833 				ref_set_non_owning(env, reg);
9834 			}
9835 		}));
9836 		return 0;
9837 	}
9838 
9839 	verbose(env, "verifier internal error: ref state missing for ref_obj_id\n");
9840 	return -EFAULT;
9841 }
9842 
9843 /* Implementation details:
9844  *
9845  * Each register points to some region of memory, which we define as an
9846  * allocation. Each allocation may embed a bpf_spin_lock which protects any
9847  * special BPF objects (bpf_list_head, bpf_rb_root, etc.) part of the same
9848  * allocation. The lock and the data it protects are colocated in the same
9849  * memory region.
9850  *
9851  * Hence, everytime a register holds a pointer value pointing to such
9852  * allocation, the verifier preserves a unique reg->id for it.
9853  *
9854  * The verifier remembers the lock 'ptr' and the lock 'id' whenever
9855  * bpf_spin_lock is called.
9856  *
9857  * To enable this, lock state in the verifier captures two values:
9858  *	active_lock.ptr = Register's type specific pointer
9859  *	active_lock.id  = A unique ID for each register pointer value
9860  *
9861  * Currently, PTR_TO_MAP_VALUE and PTR_TO_BTF_ID | MEM_ALLOC are the two
9862  * supported register types.
9863  *
9864  * The active_lock.ptr in case of map values is the reg->map_ptr, and in case of
9865  * allocated objects is the reg->btf pointer.
9866  *
9867  * The active_lock.id is non-unique for maps supporting direct_value_addr, as we
9868  * can establish the provenance of the map value statically for each distinct
9869  * lookup into such maps. They always contain a single map value hence unique
9870  * IDs for each pseudo load pessimizes the algorithm and rejects valid programs.
9871  *
9872  * So, in case of global variables, they use array maps with max_entries = 1,
9873  * hence their active_lock.ptr becomes map_ptr and id = 0 (since they all point
9874  * into the same map value as max_entries is 1, as described above).
9875  *
9876  * In case of inner map lookups, the inner map pointer has same map_ptr as the
9877  * outer map pointer (in verifier context), but each lookup into an inner map
9878  * assigns a fresh reg->id to the lookup, so while lookups into distinct inner
9879  * maps from the same outer map share the same map_ptr as active_lock.ptr, they
9880  * will get different reg->id assigned to each lookup, hence different
9881  * active_lock.id.
9882  *
9883  * In case of allocated objects, active_lock.ptr is the reg->btf, and the
9884  * reg->id is a unique ID preserved after the NULL pointer check on the pointer
9885  * returned from bpf_obj_new. Each allocation receives a new reg->id.
9886  */
9887 static int check_reg_allocation_locked(struct bpf_verifier_env *env, struct bpf_reg_state *reg)
9888 {
9889 	void *ptr;
9890 	u32 id;
9891 
9892 	switch ((int)reg->type) {
9893 	case PTR_TO_MAP_VALUE:
9894 		ptr = reg->map_ptr;
9895 		break;
9896 	case PTR_TO_BTF_ID | MEM_ALLOC:
9897 		ptr = reg->btf;
9898 		break;
9899 	default:
9900 		verbose(env, "verifier internal error: unknown reg type for lock check\n");
9901 		return -EFAULT;
9902 	}
9903 	id = reg->id;
9904 
9905 	if (!env->cur_state->active_lock.ptr)
9906 		return -EINVAL;
9907 	if (env->cur_state->active_lock.ptr != ptr ||
9908 	    env->cur_state->active_lock.id != id) {
9909 		verbose(env, "held lock and object are not in the same allocation\n");
9910 		return -EINVAL;
9911 	}
9912 	return 0;
9913 }
9914 
9915 static bool is_bpf_list_api_kfunc(u32 btf_id)
9916 {
9917 	return btf_id == special_kfunc_list[KF_bpf_list_push_front_impl] ||
9918 	       btf_id == special_kfunc_list[KF_bpf_list_push_back_impl] ||
9919 	       btf_id == special_kfunc_list[KF_bpf_list_pop_front] ||
9920 	       btf_id == special_kfunc_list[KF_bpf_list_pop_back];
9921 }
9922 
9923 static bool is_bpf_rbtree_api_kfunc(u32 btf_id)
9924 {
9925 	return btf_id == special_kfunc_list[KF_bpf_rbtree_add_impl] ||
9926 	       btf_id == special_kfunc_list[KF_bpf_rbtree_remove] ||
9927 	       btf_id == special_kfunc_list[KF_bpf_rbtree_first];
9928 }
9929 
9930 static bool is_bpf_graph_api_kfunc(u32 btf_id)
9931 {
9932 	return is_bpf_list_api_kfunc(btf_id) || is_bpf_rbtree_api_kfunc(btf_id) ||
9933 	       btf_id == special_kfunc_list[KF_bpf_refcount_acquire_impl];
9934 }
9935 
9936 static bool is_callback_calling_kfunc(u32 btf_id)
9937 {
9938 	return btf_id == special_kfunc_list[KF_bpf_rbtree_add_impl];
9939 }
9940 
9941 static bool is_rbtree_lock_required_kfunc(u32 btf_id)
9942 {
9943 	return is_bpf_rbtree_api_kfunc(btf_id);
9944 }
9945 
9946 static bool check_kfunc_is_graph_root_api(struct bpf_verifier_env *env,
9947 					  enum btf_field_type head_field_type,
9948 					  u32 kfunc_btf_id)
9949 {
9950 	bool ret;
9951 
9952 	switch (head_field_type) {
9953 	case BPF_LIST_HEAD:
9954 		ret = is_bpf_list_api_kfunc(kfunc_btf_id);
9955 		break;
9956 	case BPF_RB_ROOT:
9957 		ret = is_bpf_rbtree_api_kfunc(kfunc_btf_id);
9958 		break;
9959 	default:
9960 		verbose(env, "verifier internal error: unexpected graph root argument type %s\n",
9961 			btf_field_type_name(head_field_type));
9962 		return false;
9963 	}
9964 
9965 	if (!ret)
9966 		verbose(env, "verifier internal error: %s head arg for unknown kfunc\n",
9967 			btf_field_type_name(head_field_type));
9968 	return ret;
9969 }
9970 
9971 static bool check_kfunc_is_graph_node_api(struct bpf_verifier_env *env,
9972 					  enum btf_field_type node_field_type,
9973 					  u32 kfunc_btf_id)
9974 {
9975 	bool ret;
9976 
9977 	switch (node_field_type) {
9978 	case BPF_LIST_NODE:
9979 		ret = (kfunc_btf_id == special_kfunc_list[KF_bpf_list_push_front_impl] ||
9980 		       kfunc_btf_id == special_kfunc_list[KF_bpf_list_push_back_impl]);
9981 		break;
9982 	case BPF_RB_NODE:
9983 		ret = (kfunc_btf_id == special_kfunc_list[KF_bpf_rbtree_remove] ||
9984 		       kfunc_btf_id == special_kfunc_list[KF_bpf_rbtree_add_impl]);
9985 		break;
9986 	default:
9987 		verbose(env, "verifier internal error: unexpected graph node argument type %s\n",
9988 			btf_field_type_name(node_field_type));
9989 		return false;
9990 	}
9991 
9992 	if (!ret)
9993 		verbose(env, "verifier internal error: %s node arg for unknown kfunc\n",
9994 			btf_field_type_name(node_field_type));
9995 	return ret;
9996 }
9997 
9998 static int
9999 __process_kf_arg_ptr_to_graph_root(struct bpf_verifier_env *env,
10000 				   struct bpf_reg_state *reg, u32 regno,
10001 				   struct bpf_kfunc_call_arg_meta *meta,
10002 				   enum btf_field_type head_field_type,
10003 				   struct btf_field **head_field)
10004 {
10005 	const char *head_type_name;
10006 	struct btf_field *field;
10007 	struct btf_record *rec;
10008 	u32 head_off;
10009 
10010 	if (meta->btf != btf_vmlinux) {
10011 		verbose(env, "verifier internal error: unexpected btf mismatch in kfunc call\n");
10012 		return -EFAULT;
10013 	}
10014 
10015 	if (!check_kfunc_is_graph_root_api(env, head_field_type, meta->func_id))
10016 		return -EFAULT;
10017 
10018 	head_type_name = btf_field_type_name(head_field_type);
10019 	if (!tnum_is_const(reg->var_off)) {
10020 		verbose(env,
10021 			"R%d doesn't have constant offset. %s has to be at the constant offset\n",
10022 			regno, head_type_name);
10023 		return -EINVAL;
10024 	}
10025 
10026 	rec = reg_btf_record(reg);
10027 	head_off = reg->off + reg->var_off.value;
10028 	field = btf_record_find(rec, head_off, head_field_type);
10029 	if (!field) {
10030 		verbose(env, "%s not found at offset=%u\n", head_type_name, head_off);
10031 		return -EINVAL;
10032 	}
10033 
10034 	/* All functions require bpf_list_head to be protected using a bpf_spin_lock */
10035 	if (check_reg_allocation_locked(env, reg)) {
10036 		verbose(env, "bpf_spin_lock at off=%d must be held for %s\n",
10037 			rec->spin_lock_off, head_type_name);
10038 		return -EINVAL;
10039 	}
10040 
10041 	if (*head_field) {
10042 		verbose(env, "verifier internal error: repeating %s arg\n", head_type_name);
10043 		return -EFAULT;
10044 	}
10045 	*head_field = field;
10046 	return 0;
10047 }
10048 
10049 static int process_kf_arg_ptr_to_list_head(struct bpf_verifier_env *env,
10050 					   struct bpf_reg_state *reg, u32 regno,
10051 					   struct bpf_kfunc_call_arg_meta *meta)
10052 {
10053 	return __process_kf_arg_ptr_to_graph_root(env, reg, regno, meta, BPF_LIST_HEAD,
10054 							  &meta->arg_list_head.field);
10055 }
10056 
10057 static int process_kf_arg_ptr_to_rbtree_root(struct bpf_verifier_env *env,
10058 					     struct bpf_reg_state *reg, u32 regno,
10059 					     struct bpf_kfunc_call_arg_meta *meta)
10060 {
10061 	return __process_kf_arg_ptr_to_graph_root(env, reg, regno, meta, BPF_RB_ROOT,
10062 							  &meta->arg_rbtree_root.field);
10063 }
10064 
10065 static int
10066 __process_kf_arg_ptr_to_graph_node(struct bpf_verifier_env *env,
10067 				   struct bpf_reg_state *reg, u32 regno,
10068 				   struct bpf_kfunc_call_arg_meta *meta,
10069 				   enum btf_field_type head_field_type,
10070 				   enum btf_field_type node_field_type,
10071 				   struct btf_field **node_field)
10072 {
10073 	const char *node_type_name;
10074 	const struct btf_type *et, *t;
10075 	struct btf_field *field;
10076 	u32 node_off;
10077 
10078 	if (meta->btf != btf_vmlinux) {
10079 		verbose(env, "verifier internal error: unexpected btf mismatch in kfunc call\n");
10080 		return -EFAULT;
10081 	}
10082 
10083 	if (!check_kfunc_is_graph_node_api(env, node_field_type, meta->func_id))
10084 		return -EFAULT;
10085 
10086 	node_type_name = btf_field_type_name(node_field_type);
10087 	if (!tnum_is_const(reg->var_off)) {
10088 		verbose(env,
10089 			"R%d doesn't have constant offset. %s has to be at the constant offset\n",
10090 			regno, node_type_name);
10091 		return -EINVAL;
10092 	}
10093 
10094 	node_off = reg->off + reg->var_off.value;
10095 	field = reg_find_field_offset(reg, node_off, node_field_type);
10096 	if (!field || field->offset != node_off) {
10097 		verbose(env, "%s not found at offset=%u\n", node_type_name, node_off);
10098 		return -EINVAL;
10099 	}
10100 
10101 	field = *node_field;
10102 
10103 	et = btf_type_by_id(field->graph_root.btf, field->graph_root.value_btf_id);
10104 	t = btf_type_by_id(reg->btf, reg->btf_id);
10105 	if (!btf_struct_ids_match(&env->log, reg->btf, reg->btf_id, 0, field->graph_root.btf,
10106 				  field->graph_root.value_btf_id, true)) {
10107 		verbose(env, "operation on %s expects arg#1 %s at offset=%d "
10108 			"in struct %s, but arg is at offset=%d in struct %s\n",
10109 			btf_field_type_name(head_field_type),
10110 			btf_field_type_name(node_field_type),
10111 			field->graph_root.node_offset,
10112 			btf_name_by_offset(field->graph_root.btf, et->name_off),
10113 			node_off, btf_name_by_offset(reg->btf, t->name_off));
10114 		return -EINVAL;
10115 	}
10116 
10117 	if (node_off != field->graph_root.node_offset) {
10118 		verbose(env, "arg#1 offset=%d, but expected %s at offset=%d in struct %s\n",
10119 			node_off, btf_field_type_name(node_field_type),
10120 			field->graph_root.node_offset,
10121 			btf_name_by_offset(field->graph_root.btf, et->name_off));
10122 		return -EINVAL;
10123 	}
10124 
10125 	return 0;
10126 }
10127 
10128 static int process_kf_arg_ptr_to_list_node(struct bpf_verifier_env *env,
10129 					   struct bpf_reg_state *reg, u32 regno,
10130 					   struct bpf_kfunc_call_arg_meta *meta)
10131 {
10132 	return __process_kf_arg_ptr_to_graph_node(env, reg, regno, meta,
10133 						  BPF_LIST_HEAD, BPF_LIST_NODE,
10134 						  &meta->arg_list_head.field);
10135 }
10136 
10137 static int process_kf_arg_ptr_to_rbtree_node(struct bpf_verifier_env *env,
10138 					     struct bpf_reg_state *reg, u32 regno,
10139 					     struct bpf_kfunc_call_arg_meta *meta)
10140 {
10141 	return __process_kf_arg_ptr_to_graph_node(env, reg, regno, meta,
10142 						  BPF_RB_ROOT, BPF_RB_NODE,
10143 						  &meta->arg_rbtree_root.field);
10144 }
10145 
10146 static int check_kfunc_args(struct bpf_verifier_env *env, struct bpf_kfunc_call_arg_meta *meta,
10147 			    int insn_idx)
10148 {
10149 	const char *func_name = meta->func_name, *ref_tname;
10150 	const struct btf *btf = meta->btf;
10151 	const struct btf_param *args;
10152 	struct btf_record *rec;
10153 	u32 i, nargs;
10154 	int ret;
10155 
10156 	args = (const struct btf_param *)(meta->func_proto + 1);
10157 	nargs = btf_type_vlen(meta->func_proto);
10158 	if (nargs > MAX_BPF_FUNC_REG_ARGS) {
10159 		verbose(env, "Function %s has %d > %d args\n", func_name, nargs,
10160 			MAX_BPF_FUNC_REG_ARGS);
10161 		return -EINVAL;
10162 	}
10163 
10164 	/* Check that BTF function arguments match actual types that the
10165 	 * verifier sees.
10166 	 */
10167 	for (i = 0; i < nargs; i++) {
10168 		struct bpf_reg_state *regs = cur_regs(env), *reg = &regs[i + 1];
10169 		const struct btf_type *t, *ref_t, *resolve_ret;
10170 		enum bpf_arg_type arg_type = ARG_DONTCARE;
10171 		u32 regno = i + 1, ref_id, type_size;
10172 		bool is_ret_buf_sz = false;
10173 		int kf_arg_type;
10174 
10175 		t = btf_type_skip_modifiers(btf, args[i].type, NULL);
10176 
10177 		if (is_kfunc_arg_ignore(btf, &args[i]))
10178 			continue;
10179 
10180 		if (btf_type_is_scalar(t)) {
10181 			if (reg->type != SCALAR_VALUE) {
10182 				verbose(env, "R%d is not a scalar\n", regno);
10183 				return -EINVAL;
10184 			}
10185 
10186 			if (is_kfunc_arg_constant(meta->btf, &args[i])) {
10187 				if (meta->arg_constant.found) {
10188 					verbose(env, "verifier internal error: only one constant argument permitted\n");
10189 					return -EFAULT;
10190 				}
10191 				if (!tnum_is_const(reg->var_off)) {
10192 					verbose(env, "R%d must be a known constant\n", regno);
10193 					return -EINVAL;
10194 				}
10195 				ret = mark_chain_precision(env, regno);
10196 				if (ret < 0)
10197 					return ret;
10198 				meta->arg_constant.found = true;
10199 				meta->arg_constant.value = reg->var_off.value;
10200 			} else if (is_kfunc_arg_scalar_with_name(btf, &args[i], "rdonly_buf_size")) {
10201 				meta->r0_rdonly = true;
10202 				is_ret_buf_sz = true;
10203 			} else if (is_kfunc_arg_scalar_with_name(btf, &args[i], "rdwr_buf_size")) {
10204 				is_ret_buf_sz = true;
10205 			}
10206 
10207 			if (is_ret_buf_sz) {
10208 				if (meta->r0_size) {
10209 					verbose(env, "2 or more rdonly/rdwr_buf_size parameters for kfunc");
10210 					return -EINVAL;
10211 				}
10212 
10213 				if (!tnum_is_const(reg->var_off)) {
10214 					verbose(env, "R%d is not a const\n", regno);
10215 					return -EINVAL;
10216 				}
10217 
10218 				meta->r0_size = reg->var_off.value;
10219 				ret = mark_chain_precision(env, regno);
10220 				if (ret)
10221 					return ret;
10222 			}
10223 			continue;
10224 		}
10225 
10226 		if (!btf_type_is_ptr(t)) {
10227 			verbose(env, "Unrecognized arg#%d type %s\n", i, btf_type_str(t));
10228 			return -EINVAL;
10229 		}
10230 
10231 		if ((is_kfunc_trusted_args(meta) || is_kfunc_rcu(meta)) &&
10232 		    (register_is_null(reg) || type_may_be_null(reg->type))) {
10233 			verbose(env, "Possibly NULL pointer passed to trusted arg%d\n", i);
10234 			return -EACCES;
10235 		}
10236 
10237 		if (reg->ref_obj_id) {
10238 			if (is_kfunc_release(meta) && meta->ref_obj_id) {
10239 				verbose(env, "verifier internal error: more than one arg with ref_obj_id R%d %u %u\n",
10240 					regno, reg->ref_obj_id,
10241 					meta->ref_obj_id);
10242 				return -EFAULT;
10243 			}
10244 			meta->ref_obj_id = reg->ref_obj_id;
10245 			if (is_kfunc_release(meta))
10246 				meta->release_regno = regno;
10247 		}
10248 
10249 		ref_t = btf_type_skip_modifiers(btf, t->type, &ref_id);
10250 		ref_tname = btf_name_by_offset(btf, ref_t->name_off);
10251 
10252 		kf_arg_type = get_kfunc_ptr_arg_type(env, meta, t, ref_t, ref_tname, args, i, nargs);
10253 		if (kf_arg_type < 0)
10254 			return kf_arg_type;
10255 
10256 		switch (kf_arg_type) {
10257 		case KF_ARG_PTR_TO_ALLOC_BTF_ID:
10258 		case KF_ARG_PTR_TO_BTF_ID:
10259 			if (!is_kfunc_trusted_args(meta) && !is_kfunc_rcu(meta))
10260 				break;
10261 
10262 			if (!is_trusted_reg(reg)) {
10263 				if (!is_kfunc_rcu(meta)) {
10264 					verbose(env, "R%d must be referenced or trusted\n", regno);
10265 					return -EINVAL;
10266 				}
10267 				if (!is_rcu_reg(reg)) {
10268 					verbose(env, "R%d must be a rcu pointer\n", regno);
10269 					return -EINVAL;
10270 				}
10271 			}
10272 
10273 			fallthrough;
10274 		case KF_ARG_PTR_TO_CTX:
10275 			/* Trusted arguments have the same offset checks as release arguments */
10276 			arg_type |= OBJ_RELEASE;
10277 			break;
10278 		case KF_ARG_PTR_TO_DYNPTR:
10279 		case KF_ARG_PTR_TO_ITER:
10280 		case KF_ARG_PTR_TO_LIST_HEAD:
10281 		case KF_ARG_PTR_TO_LIST_NODE:
10282 		case KF_ARG_PTR_TO_RB_ROOT:
10283 		case KF_ARG_PTR_TO_RB_NODE:
10284 		case KF_ARG_PTR_TO_MEM:
10285 		case KF_ARG_PTR_TO_MEM_SIZE:
10286 		case KF_ARG_PTR_TO_CALLBACK:
10287 		case KF_ARG_PTR_TO_REFCOUNTED_KPTR:
10288 			/* Trusted by default */
10289 			break;
10290 		default:
10291 			WARN_ON_ONCE(1);
10292 			return -EFAULT;
10293 		}
10294 
10295 		if (is_kfunc_release(meta) && reg->ref_obj_id)
10296 			arg_type |= OBJ_RELEASE;
10297 		ret = check_func_arg_reg_off(env, reg, regno, arg_type);
10298 		if (ret < 0)
10299 			return ret;
10300 
10301 		switch (kf_arg_type) {
10302 		case KF_ARG_PTR_TO_CTX:
10303 			if (reg->type != PTR_TO_CTX) {
10304 				verbose(env, "arg#%d expected pointer to ctx, but got %s\n", i, btf_type_str(t));
10305 				return -EINVAL;
10306 			}
10307 
10308 			if (meta->func_id == special_kfunc_list[KF_bpf_cast_to_kern_ctx]) {
10309 				ret = get_kern_ctx_btf_id(&env->log, resolve_prog_type(env->prog));
10310 				if (ret < 0)
10311 					return -EINVAL;
10312 				meta->ret_btf_id  = ret;
10313 			}
10314 			break;
10315 		case KF_ARG_PTR_TO_ALLOC_BTF_ID:
10316 			if (reg->type != (PTR_TO_BTF_ID | MEM_ALLOC)) {
10317 				verbose(env, "arg#%d expected pointer to allocated object\n", i);
10318 				return -EINVAL;
10319 			}
10320 			if (!reg->ref_obj_id) {
10321 				verbose(env, "allocated object must be referenced\n");
10322 				return -EINVAL;
10323 			}
10324 			if (meta->btf == btf_vmlinux &&
10325 			    meta->func_id == special_kfunc_list[KF_bpf_obj_drop_impl]) {
10326 				meta->arg_obj_drop.btf = reg->btf;
10327 				meta->arg_obj_drop.btf_id = reg->btf_id;
10328 			}
10329 			break;
10330 		case KF_ARG_PTR_TO_DYNPTR:
10331 		{
10332 			enum bpf_arg_type dynptr_arg_type = ARG_PTR_TO_DYNPTR;
10333 
10334 			if (reg->type != PTR_TO_STACK &&
10335 			    reg->type != CONST_PTR_TO_DYNPTR) {
10336 				verbose(env, "arg#%d expected pointer to stack or dynptr_ptr\n", i);
10337 				return -EINVAL;
10338 			}
10339 
10340 			if (reg->type == CONST_PTR_TO_DYNPTR)
10341 				dynptr_arg_type |= MEM_RDONLY;
10342 
10343 			if (is_kfunc_arg_uninit(btf, &args[i]))
10344 				dynptr_arg_type |= MEM_UNINIT;
10345 
10346 			if (meta->func_id == special_kfunc_list[KF_bpf_dynptr_from_skb])
10347 				dynptr_arg_type |= DYNPTR_TYPE_SKB;
10348 			else if (meta->func_id == special_kfunc_list[KF_bpf_dynptr_from_xdp])
10349 				dynptr_arg_type |= DYNPTR_TYPE_XDP;
10350 
10351 			ret = process_dynptr_func(env, regno, insn_idx, dynptr_arg_type);
10352 			if (ret < 0)
10353 				return ret;
10354 
10355 			if (!(dynptr_arg_type & MEM_UNINIT)) {
10356 				int id = dynptr_id(env, reg);
10357 
10358 				if (id < 0) {
10359 					verbose(env, "verifier internal error: failed to obtain dynptr id\n");
10360 					return id;
10361 				}
10362 				meta->initialized_dynptr.id = id;
10363 				meta->initialized_dynptr.type = dynptr_get_type(env, reg);
10364 			}
10365 
10366 			break;
10367 		}
10368 		case KF_ARG_PTR_TO_ITER:
10369 			ret = process_iter_arg(env, regno, insn_idx, meta);
10370 			if (ret < 0)
10371 				return ret;
10372 			break;
10373 		case KF_ARG_PTR_TO_LIST_HEAD:
10374 			if (reg->type != PTR_TO_MAP_VALUE &&
10375 			    reg->type != (PTR_TO_BTF_ID | MEM_ALLOC)) {
10376 				verbose(env, "arg#%d expected pointer to map value or allocated object\n", i);
10377 				return -EINVAL;
10378 			}
10379 			if (reg->type == (PTR_TO_BTF_ID | MEM_ALLOC) && !reg->ref_obj_id) {
10380 				verbose(env, "allocated object must be referenced\n");
10381 				return -EINVAL;
10382 			}
10383 			ret = process_kf_arg_ptr_to_list_head(env, reg, regno, meta);
10384 			if (ret < 0)
10385 				return ret;
10386 			break;
10387 		case KF_ARG_PTR_TO_RB_ROOT:
10388 			if (reg->type != PTR_TO_MAP_VALUE &&
10389 			    reg->type != (PTR_TO_BTF_ID | MEM_ALLOC)) {
10390 				verbose(env, "arg#%d expected pointer to map value or allocated object\n", i);
10391 				return -EINVAL;
10392 			}
10393 			if (reg->type == (PTR_TO_BTF_ID | MEM_ALLOC) && !reg->ref_obj_id) {
10394 				verbose(env, "allocated object must be referenced\n");
10395 				return -EINVAL;
10396 			}
10397 			ret = process_kf_arg_ptr_to_rbtree_root(env, reg, regno, meta);
10398 			if (ret < 0)
10399 				return ret;
10400 			break;
10401 		case KF_ARG_PTR_TO_LIST_NODE:
10402 			if (reg->type != (PTR_TO_BTF_ID | MEM_ALLOC)) {
10403 				verbose(env, "arg#%d expected pointer to allocated object\n", i);
10404 				return -EINVAL;
10405 			}
10406 			if (!reg->ref_obj_id) {
10407 				verbose(env, "allocated object must be referenced\n");
10408 				return -EINVAL;
10409 			}
10410 			ret = process_kf_arg_ptr_to_list_node(env, reg, regno, meta);
10411 			if (ret < 0)
10412 				return ret;
10413 			break;
10414 		case KF_ARG_PTR_TO_RB_NODE:
10415 			if (meta->func_id == special_kfunc_list[KF_bpf_rbtree_remove]) {
10416 				if (!type_is_non_owning_ref(reg->type) || reg->ref_obj_id) {
10417 					verbose(env, "rbtree_remove node input must be non-owning ref\n");
10418 					return -EINVAL;
10419 				}
10420 				if (in_rbtree_lock_required_cb(env)) {
10421 					verbose(env, "rbtree_remove not allowed in rbtree cb\n");
10422 					return -EINVAL;
10423 				}
10424 			} else {
10425 				if (reg->type != (PTR_TO_BTF_ID | MEM_ALLOC)) {
10426 					verbose(env, "arg#%d expected pointer to allocated object\n", i);
10427 					return -EINVAL;
10428 				}
10429 				if (!reg->ref_obj_id) {
10430 					verbose(env, "allocated object must be referenced\n");
10431 					return -EINVAL;
10432 				}
10433 			}
10434 
10435 			ret = process_kf_arg_ptr_to_rbtree_node(env, reg, regno, meta);
10436 			if (ret < 0)
10437 				return ret;
10438 			break;
10439 		case KF_ARG_PTR_TO_BTF_ID:
10440 			/* Only base_type is checked, further checks are done here */
10441 			if ((base_type(reg->type) != PTR_TO_BTF_ID ||
10442 			     (bpf_type_has_unsafe_modifiers(reg->type) && !is_rcu_reg(reg))) &&
10443 			    !reg2btf_ids[base_type(reg->type)]) {
10444 				verbose(env, "arg#%d is %s ", i, reg_type_str(env, reg->type));
10445 				verbose(env, "expected %s or socket\n",
10446 					reg_type_str(env, base_type(reg->type) |
10447 							  (type_flag(reg->type) & BPF_REG_TRUSTED_MODIFIERS)));
10448 				return -EINVAL;
10449 			}
10450 			ret = process_kf_arg_ptr_to_btf_id(env, reg, ref_t, ref_tname, ref_id, meta, i);
10451 			if (ret < 0)
10452 				return ret;
10453 			break;
10454 		case KF_ARG_PTR_TO_MEM:
10455 			resolve_ret = btf_resolve_size(btf, ref_t, &type_size);
10456 			if (IS_ERR(resolve_ret)) {
10457 				verbose(env, "arg#%d reference type('%s %s') size cannot be determined: %ld\n",
10458 					i, btf_type_str(ref_t), ref_tname, PTR_ERR(resolve_ret));
10459 				return -EINVAL;
10460 			}
10461 			ret = check_mem_reg(env, reg, regno, type_size);
10462 			if (ret < 0)
10463 				return ret;
10464 			break;
10465 		case KF_ARG_PTR_TO_MEM_SIZE:
10466 		{
10467 			struct bpf_reg_state *size_reg = &regs[regno + 1];
10468 			const struct btf_param *size_arg = &args[i + 1];
10469 
10470 			ret = check_kfunc_mem_size_reg(env, size_reg, regno + 1);
10471 			if (ret < 0) {
10472 				verbose(env, "arg#%d arg#%d memory, len pair leads to invalid memory access\n", i, i + 1);
10473 				return ret;
10474 			}
10475 
10476 			if (is_kfunc_arg_const_mem_size(meta->btf, size_arg, size_reg)) {
10477 				if (meta->arg_constant.found) {
10478 					verbose(env, "verifier internal error: only one constant argument permitted\n");
10479 					return -EFAULT;
10480 				}
10481 				if (!tnum_is_const(size_reg->var_off)) {
10482 					verbose(env, "R%d must be a known constant\n", regno + 1);
10483 					return -EINVAL;
10484 				}
10485 				meta->arg_constant.found = true;
10486 				meta->arg_constant.value = size_reg->var_off.value;
10487 			}
10488 
10489 			/* Skip next '__sz' or '__szk' argument */
10490 			i++;
10491 			break;
10492 		}
10493 		case KF_ARG_PTR_TO_CALLBACK:
10494 			meta->subprogno = reg->subprogno;
10495 			break;
10496 		case KF_ARG_PTR_TO_REFCOUNTED_KPTR:
10497 			if (!type_is_ptr_alloc_obj(reg->type) && !type_is_non_owning_ref(reg->type)) {
10498 				verbose(env, "arg#%d is neither owning or non-owning ref\n", i);
10499 				return -EINVAL;
10500 			}
10501 
10502 			rec = reg_btf_record(reg);
10503 			if (!rec) {
10504 				verbose(env, "verifier internal error: Couldn't find btf_record\n");
10505 				return -EFAULT;
10506 			}
10507 
10508 			if (rec->refcount_off < 0) {
10509 				verbose(env, "arg#%d doesn't point to a type with bpf_refcount field\n", i);
10510 				return -EINVAL;
10511 			}
10512 
10513 			meta->arg_refcount_acquire.btf = reg->btf;
10514 			meta->arg_refcount_acquire.btf_id = reg->btf_id;
10515 			break;
10516 		}
10517 	}
10518 
10519 	if (is_kfunc_release(meta) && !meta->release_regno) {
10520 		verbose(env, "release kernel function %s expects refcounted PTR_TO_BTF_ID\n",
10521 			func_name);
10522 		return -EINVAL;
10523 	}
10524 
10525 	return 0;
10526 }
10527 
10528 static int fetch_kfunc_meta(struct bpf_verifier_env *env,
10529 			    struct bpf_insn *insn,
10530 			    struct bpf_kfunc_call_arg_meta *meta,
10531 			    const char **kfunc_name)
10532 {
10533 	const struct btf_type *func, *func_proto;
10534 	u32 func_id, *kfunc_flags;
10535 	const char *func_name;
10536 	struct btf *desc_btf;
10537 
10538 	if (kfunc_name)
10539 		*kfunc_name = NULL;
10540 
10541 	if (!insn->imm)
10542 		return -EINVAL;
10543 
10544 	desc_btf = find_kfunc_desc_btf(env, insn->off);
10545 	if (IS_ERR(desc_btf))
10546 		return PTR_ERR(desc_btf);
10547 
10548 	func_id = insn->imm;
10549 	func = btf_type_by_id(desc_btf, func_id);
10550 	func_name = btf_name_by_offset(desc_btf, func->name_off);
10551 	if (kfunc_name)
10552 		*kfunc_name = func_name;
10553 	func_proto = btf_type_by_id(desc_btf, func->type);
10554 
10555 	kfunc_flags = btf_kfunc_id_set_contains(desc_btf, resolve_prog_type(env->prog), func_id);
10556 	if (!kfunc_flags) {
10557 		return -EACCES;
10558 	}
10559 
10560 	memset(meta, 0, sizeof(*meta));
10561 	meta->btf = desc_btf;
10562 	meta->func_id = func_id;
10563 	meta->kfunc_flags = *kfunc_flags;
10564 	meta->func_proto = func_proto;
10565 	meta->func_name = func_name;
10566 
10567 	return 0;
10568 }
10569 
10570 static int check_kfunc_call(struct bpf_verifier_env *env, struct bpf_insn *insn,
10571 			    int *insn_idx_p)
10572 {
10573 	const struct btf_type *t, *ptr_type;
10574 	u32 i, nargs, ptr_type_id, release_ref_obj_id;
10575 	struct bpf_reg_state *regs = cur_regs(env);
10576 	const char *func_name, *ptr_type_name;
10577 	bool sleepable, rcu_lock, rcu_unlock;
10578 	struct bpf_kfunc_call_arg_meta meta;
10579 	struct bpf_insn_aux_data *insn_aux;
10580 	int err, insn_idx = *insn_idx_p;
10581 	const struct btf_param *args;
10582 	const struct btf_type *ret_t;
10583 	struct btf *desc_btf;
10584 
10585 	/* skip for now, but return error when we find this in fixup_kfunc_call */
10586 	if (!insn->imm)
10587 		return 0;
10588 
10589 	err = fetch_kfunc_meta(env, insn, &meta, &func_name);
10590 	if (err == -EACCES && func_name)
10591 		verbose(env, "calling kernel function %s is not allowed\n", func_name);
10592 	if (err)
10593 		return err;
10594 	desc_btf = meta.btf;
10595 	insn_aux = &env->insn_aux_data[insn_idx];
10596 
10597 	insn_aux->is_iter_next = is_iter_next_kfunc(&meta);
10598 
10599 	if (is_kfunc_destructive(&meta) && !capable(CAP_SYS_BOOT)) {
10600 		verbose(env, "destructive kfunc calls require CAP_SYS_BOOT capability\n");
10601 		return -EACCES;
10602 	}
10603 
10604 	sleepable = is_kfunc_sleepable(&meta);
10605 	if (sleepable && !env->prog->aux->sleepable) {
10606 		verbose(env, "program must be sleepable to call sleepable kfunc %s\n", func_name);
10607 		return -EACCES;
10608 	}
10609 
10610 	rcu_lock = is_kfunc_bpf_rcu_read_lock(&meta);
10611 	rcu_unlock = is_kfunc_bpf_rcu_read_unlock(&meta);
10612 
10613 	if (env->cur_state->active_rcu_lock) {
10614 		struct bpf_func_state *state;
10615 		struct bpf_reg_state *reg;
10616 
10617 		if (rcu_lock) {
10618 			verbose(env, "nested rcu read lock (kernel function %s)\n", func_name);
10619 			return -EINVAL;
10620 		} else if (rcu_unlock) {
10621 			bpf_for_each_reg_in_vstate(env->cur_state, state, reg, ({
10622 				if (reg->type & MEM_RCU) {
10623 					reg->type &= ~(MEM_RCU | PTR_MAYBE_NULL);
10624 					reg->type |= PTR_UNTRUSTED;
10625 				}
10626 			}));
10627 			env->cur_state->active_rcu_lock = false;
10628 		} else if (sleepable) {
10629 			verbose(env, "kernel func %s is sleepable within rcu_read_lock region\n", func_name);
10630 			return -EACCES;
10631 		}
10632 	} else if (rcu_lock) {
10633 		env->cur_state->active_rcu_lock = true;
10634 	} else if (rcu_unlock) {
10635 		verbose(env, "unmatched rcu read unlock (kernel function %s)\n", func_name);
10636 		return -EINVAL;
10637 	}
10638 
10639 	/* Check the arguments */
10640 	err = check_kfunc_args(env, &meta, insn_idx);
10641 	if (err < 0)
10642 		return err;
10643 	/* In case of release function, we get register number of refcounted
10644 	 * PTR_TO_BTF_ID in bpf_kfunc_arg_meta, do the release now.
10645 	 */
10646 	if (meta.release_regno) {
10647 		err = release_reference(env, regs[meta.release_regno].ref_obj_id);
10648 		if (err) {
10649 			verbose(env, "kfunc %s#%d reference has not been acquired before\n",
10650 				func_name, meta.func_id);
10651 			return err;
10652 		}
10653 	}
10654 
10655 	if (meta.func_id == special_kfunc_list[KF_bpf_list_push_front_impl] ||
10656 	    meta.func_id == special_kfunc_list[KF_bpf_list_push_back_impl] ||
10657 	    meta.func_id == special_kfunc_list[KF_bpf_rbtree_add_impl]) {
10658 		release_ref_obj_id = regs[BPF_REG_2].ref_obj_id;
10659 		insn_aux->insert_off = regs[BPF_REG_2].off;
10660 		err = ref_convert_owning_non_owning(env, release_ref_obj_id);
10661 		if (err) {
10662 			verbose(env, "kfunc %s#%d conversion of owning ref to non-owning failed\n",
10663 				func_name, meta.func_id);
10664 			return err;
10665 		}
10666 
10667 		err = release_reference(env, release_ref_obj_id);
10668 		if (err) {
10669 			verbose(env, "kfunc %s#%d reference has not been acquired before\n",
10670 				func_name, meta.func_id);
10671 			return err;
10672 		}
10673 	}
10674 
10675 	if (meta.func_id == special_kfunc_list[KF_bpf_rbtree_add_impl]) {
10676 		err = __check_func_call(env, insn, insn_idx_p, meta.subprogno,
10677 					set_rbtree_add_callback_state);
10678 		if (err) {
10679 			verbose(env, "kfunc %s#%d failed callback verification\n",
10680 				func_name, meta.func_id);
10681 			return err;
10682 		}
10683 	}
10684 
10685 	for (i = 0; i < CALLER_SAVED_REGS; i++)
10686 		mark_reg_not_init(env, regs, caller_saved[i]);
10687 
10688 	/* Check return type */
10689 	t = btf_type_skip_modifiers(desc_btf, meta.func_proto->type, NULL);
10690 
10691 	if (is_kfunc_acquire(&meta) && !btf_type_is_struct_ptr(meta.btf, t)) {
10692 		/* Only exception is bpf_obj_new_impl */
10693 		if (meta.btf != btf_vmlinux ||
10694 		    (meta.func_id != special_kfunc_list[KF_bpf_obj_new_impl] &&
10695 		     meta.func_id != special_kfunc_list[KF_bpf_refcount_acquire_impl])) {
10696 			verbose(env, "acquire kernel function does not return PTR_TO_BTF_ID\n");
10697 			return -EINVAL;
10698 		}
10699 	}
10700 
10701 	if (btf_type_is_scalar(t)) {
10702 		mark_reg_unknown(env, regs, BPF_REG_0);
10703 		mark_btf_func_reg_size(env, BPF_REG_0, t->size);
10704 	} else if (btf_type_is_ptr(t)) {
10705 		ptr_type = btf_type_skip_modifiers(desc_btf, t->type, &ptr_type_id);
10706 
10707 		if (meta.btf == btf_vmlinux && btf_id_set_contains(&special_kfunc_set, meta.func_id)) {
10708 			if (meta.func_id == special_kfunc_list[KF_bpf_obj_new_impl]) {
10709 				struct btf *ret_btf;
10710 				u32 ret_btf_id;
10711 
10712 				if (unlikely(!bpf_global_ma_set))
10713 					return -ENOMEM;
10714 
10715 				if (((u64)(u32)meta.arg_constant.value) != meta.arg_constant.value) {
10716 					verbose(env, "local type ID argument must be in range [0, U32_MAX]\n");
10717 					return -EINVAL;
10718 				}
10719 
10720 				ret_btf = env->prog->aux->btf;
10721 				ret_btf_id = meta.arg_constant.value;
10722 
10723 				/* This may be NULL due to user not supplying a BTF */
10724 				if (!ret_btf) {
10725 					verbose(env, "bpf_obj_new requires prog BTF\n");
10726 					return -EINVAL;
10727 				}
10728 
10729 				ret_t = btf_type_by_id(ret_btf, ret_btf_id);
10730 				if (!ret_t || !__btf_type_is_struct(ret_t)) {
10731 					verbose(env, "bpf_obj_new type ID argument must be of a struct\n");
10732 					return -EINVAL;
10733 				}
10734 
10735 				mark_reg_known_zero(env, regs, BPF_REG_0);
10736 				regs[BPF_REG_0].type = PTR_TO_BTF_ID | MEM_ALLOC;
10737 				regs[BPF_REG_0].btf = ret_btf;
10738 				regs[BPF_REG_0].btf_id = ret_btf_id;
10739 
10740 				insn_aux->obj_new_size = ret_t->size;
10741 				insn_aux->kptr_struct_meta =
10742 					btf_find_struct_meta(ret_btf, ret_btf_id);
10743 			} else if (meta.func_id == special_kfunc_list[KF_bpf_refcount_acquire_impl]) {
10744 				mark_reg_known_zero(env, regs, BPF_REG_0);
10745 				regs[BPF_REG_0].type = PTR_TO_BTF_ID | MEM_ALLOC;
10746 				regs[BPF_REG_0].btf = meta.arg_refcount_acquire.btf;
10747 				regs[BPF_REG_0].btf_id = meta.arg_refcount_acquire.btf_id;
10748 
10749 				insn_aux->kptr_struct_meta =
10750 					btf_find_struct_meta(meta.arg_refcount_acquire.btf,
10751 							     meta.arg_refcount_acquire.btf_id);
10752 			} else if (meta.func_id == special_kfunc_list[KF_bpf_list_pop_front] ||
10753 				   meta.func_id == special_kfunc_list[KF_bpf_list_pop_back]) {
10754 				struct btf_field *field = meta.arg_list_head.field;
10755 
10756 				mark_reg_graph_node(regs, BPF_REG_0, &field->graph_root);
10757 			} else if (meta.func_id == special_kfunc_list[KF_bpf_rbtree_remove] ||
10758 				   meta.func_id == special_kfunc_list[KF_bpf_rbtree_first]) {
10759 				struct btf_field *field = meta.arg_rbtree_root.field;
10760 
10761 				mark_reg_graph_node(regs, BPF_REG_0, &field->graph_root);
10762 			} else if (meta.func_id == special_kfunc_list[KF_bpf_cast_to_kern_ctx]) {
10763 				mark_reg_known_zero(env, regs, BPF_REG_0);
10764 				regs[BPF_REG_0].type = PTR_TO_BTF_ID | PTR_TRUSTED;
10765 				regs[BPF_REG_0].btf = desc_btf;
10766 				regs[BPF_REG_0].btf_id = meta.ret_btf_id;
10767 			} else if (meta.func_id == special_kfunc_list[KF_bpf_rdonly_cast]) {
10768 				ret_t = btf_type_by_id(desc_btf, meta.arg_constant.value);
10769 				if (!ret_t || !btf_type_is_struct(ret_t)) {
10770 					verbose(env,
10771 						"kfunc bpf_rdonly_cast type ID argument must be of a struct\n");
10772 					return -EINVAL;
10773 				}
10774 
10775 				mark_reg_known_zero(env, regs, BPF_REG_0);
10776 				regs[BPF_REG_0].type = PTR_TO_BTF_ID | PTR_UNTRUSTED;
10777 				regs[BPF_REG_0].btf = desc_btf;
10778 				regs[BPF_REG_0].btf_id = meta.arg_constant.value;
10779 			} else if (meta.func_id == special_kfunc_list[KF_bpf_dynptr_slice] ||
10780 				   meta.func_id == special_kfunc_list[KF_bpf_dynptr_slice_rdwr]) {
10781 				enum bpf_type_flag type_flag = get_dynptr_type_flag(meta.initialized_dynptr.type);
10782 
10783 				mark_reg_known_zero(env, regs, BPF_REG_0);
10784 
10785 				if (!meta.arg_constant.found) {
10786 					verbose(env, "verifier internal error: bpf_dynptr_slice(_rdwr) no constant size\n");
10787 					return -EFAULT;
10788 				}
10789 
10790 				regs[BPF_REG_0].mem_size = meta.arg_constant.value;
10791 
10792 				/* PTR_MAYBE_NULL will be added when is_kfunc_ret_null is checked */
10793 				regs[BPF_REG_0].type = PTR_TO_MEM | type_flag;
10794 
10795 				if (meta.func_id == special_kfunc_list[KF_bpf_dynptr_slice]) {
10796 					regs[BPF_REG_0].type |= MEM_RDONLY;
10797 				} else {
10798 					/* this will set env->seen_direct_write to true */
10799 					if (!may_access_direct_pkt_data(env, NULL, BPF_WRITE)) {
10800 						verbose(env, "the prog does not allow writes to packet data\n");
10801 						return -EINVAL;
10802 					}
10803 				}
10804 
10805 				if (!meta.initialized_dynptr.id) {
10806 					verbose(env, "verifier internal error: no dynptr id\n");
10807 					return -EFAULT;
10808 				}
10809 				regs[BPF_REG_0].dynptr_id = meta.initialized_dynptr.id;
10810 
10811 				/* we don't need to set BPF_REG_0's ref obj id
10812 				 * because packet slices are not refcounted (see
10813 				 * dynptr_type_refcounted)
10814 				 */
10815 			} else {
10816 				verbose(env, "kernel function %s unhandled dynamic return type\n",
10817 					meta.func_name);
10818 				return -EFAULT;
10819 			}
10820 		} else if (!__btf_type_is_struct(ptr_type)) {
10821 			if (!meta.r0_size) {
10822 				__u32 sz;
10823 
10824 				if (!IS_ERR(btf_resolve_size(desc_btf, ptr_type, &sz))) {
10825 					meta.r0_size = sz;
10826 					meta.r0_rdonly = true;
10827 				}
10828 			}
10829 			if (!meta.r0_size) {
10830 				ptr_type_name = btf_name_by_offset(desc_btf,
10831 								   ptr_type->name_off);
10832 				verbose(env,
10833 					"kernel function %s returns pointer type %s %s is not supported\n",
10834 					func_name,
10835 					btf_type_str(ptr_type),
10836 					ptr_type_name);
10837 				return -EINVAL;
10838 			}
10839 
10840 			mark_reg_known_zero(env, regs, BPF_REG_0);
10841 			regs[BPF_REG_0].type = PTR_TO_MEM;
10842 			regs[BPF_REG_0].mem_size = meta.r0_size;
10843 
10844 			if (meta.r0_rdonly)
10845 				regs[BPF_REG_0].type |= MEM_RDONLY;
10846 
10847 			/* Ensures we don't access the memory after a release_reference() */
10848 			if (meta.ref_obj_id)
10849 				regs[BPF_REG_0].ref_obj_id = meta.ref_obj_id;
10850 		} else {
10851 			mark_reg_known_zero(env, regs, BPF_REG_0);
10852 			regs[BPF_REG_0].btf = desc_btf;
10853 			regs[BPF_REG_0].type = PTR_TO_BTF_ID;
10854 			regs[BPF_REG_0].btf_id = ptr_type_id;
10855 		}
10856 
10857 		if (is_kfunc_ret_null(&meta)) {
10858 			regs[BPF_REG_0].type |= PTR_MAYBE_NULL;
10859 			/* For mark_ptr_or_null_reg, see 93c230e3f5bd6 */
10860 			regs[BPF_REG_0].id = ++env->id_gen;
10861 		}
10862 		mark_btf_func_reg_size(env, BPF_REG_0, sizeof(void *));
10863 		if (is_kfunc_acquire(&meta)) {
10864 			int id = acquire_reference_state(env, insn_idx);
10865 
10866 			if (id < 0)
10867 				return id;
10868 			if (is_kfunc_ret_null(&meta))
10869 				regs[BPF_REG_0].id = id;
10870 			regs[BPF_REG_0].ref_obj_id = id;
10871 		} else if (meta.func_id == special_kfunc_list[KF_bpf_rbtree_first]) {
10872 			ref_set_non_owning(env, &regs[BPF_REG_0]);
10873 		}
10874 
10875 		if (reg_may_point_to_spin_lock(&regs[BPF_REG_0]) && !regs[BPF_REG_0].id)
10876 			regs[BPF_REG_0].id = ++env->id_gen;
10877 	} else if (btf_type_is_void(t)) {
10878 		if (meta.btf == btf_vmlinux && btf_id_set_contains(&special_kfunc_set, meta.func_id)) {
10879 			if (meta.func_id == special_kfunc_list[KF_bpf_obj_drop_impl]) {
10880 				insn_aux->kptr_struct_meta =
10881 					btf_find_struct_meta(meta.arg_obj_drop.btf,
10882 							     meta.arg_obj_drop.btf_id);
10883 			}
10884 		}
10885 	}
10886 
10887 	nargs = btf_type_vlen(meta.func_proto);
10888 	args = (const struct btf_param *)(meta.func_proto + 1);
10889 	for (i = 0; i < nargs; i++) {
10890 		u32 regno = i + 1;
10891 
10892 		t = btf_type_skip_modifiers(desc_btf, args[i].type, NULL);
10893 		if (btf_type_is_ptr(t))
10894 			mark_btf_func_reg_size(env, regno, sizeof(void *));
10895 		else
10896 			/* scalar. ensured by btf_check_kfunc_arg_match() */
10897 			mark_btf_func_reg_size(env, regno, t->size);
10898 	}
10899 
10900 	if (is_iter_next_kfunc(&meta)) {
10901 		err = process_iter_next_call(env, insn_idx, &meta);
10902 		if (err)
10903 			return err;
10904 	}
10905 
10906 	return 0;
10907 }
10908 
10909 static bool signed_add_overflows(s64 a, s64 b)
10910 {
10911 	/* Do the add in u64, where overflow is well-defined */
10912 	s64 res = (s64)((u64)a + (u64)b);
10913 
10914 	if (b < 0)
10915 		return res > a;
10916 	return res < a;
10917 }
10918 
10919 static bool signed_add32_overflows(s32 a, s32 b)
10920 {
10921 	/* Do the add in u32, where overflow is well-defined */
10922 	s32 res = (s32)((u32)a + (u32)b);
10923 
10924 	if (b < 0)
10925 		return res > a;
10926 	return res < a;
10927 }
10928 
10929 static bool signed_sub_overflows(s64 a, s64 b)
10930 {
10931 	/* Do the sub in u64, where overflow is well-defined */
10932 	s64 res = (s64)((u64)a - (u64)b);
10933 
10934 	if (b < 0)
10935 		return res < a;
10936 	return res > a;
10937 }
10938 
10939 static bool signed_sub32_overflows(s32 a, s32 b)
10940 {
10941 	/* Do the sub in u32, where overflow is well-defined */
10942 	s32 res = (s32)((u32)a - (u32)b);
10943 
10944 	if (b < 0)
10945 		return res < a;
10946 	return res > a;
10947 }
10948 
10949 static bool check_reg_sane_offset(struct bpf_verifier_env *env,
10950 				  const struct bpf_reg_state *reg,
10951 				  enum bpf_reg_type type)
10952 {
10953 	bool known = tnum_is_const(reg->var_off);
10954 	s64 val = reg->var_off.value;
10955 	s64 smin = reg->smin_value;
10956 
10957 	if (known && (val >= BPF_MAX_VAR_OFF || val <= -BPF_MAX_VAR_OFF)) {
10958 		verbose(env, "math between %s pointer and %lld is not allowed\n",
10959 			reg_type_str(env, type), val);
10960 		return false;
10961 	}
10962 
10963 	if (reg->off >= BPF_MAX_VAR_OFF || reg->off <= -BPF_MAX_VAR_OFF) {
10964 		verbose(env, "%s pointer offset %d is not allowed\n",
10965 			reg_type_str(env, type), reg->off);
10966 		return false;
10967 	}
10968 
10969 	if (smin == S64_MIN) {
10970 		verbose(env, "math between %s pointer and register with unbounded min value is not allowed\n",
10971 			reg_type_str(env, type));
10972 		return false;
10973 	}
10974 
10975 	if (smin >= BPF_MAX_VAR_OFF || smin <= -BPF_MAX_VAR_OFF) {
10976 		verbose(env, "value %lld makes %s pointer be out of bounds\n",
10977 			smin, reg_type_str(env, type));
10978 		return false;
10979 	}
10980 
10981 	return true;
10982 }
10983 
10984 enum {
10985 	REASON_BOUNDS	= -1,
10986 	REASON_TYPE	= -2,
10987 	REASON_PATHS	= -3,
10988 	REASON_LIMIT	= -4,
10989 	REASON_STACK	= -5,
10990 };
10991 
10992 static int retrieve_ptr_limit(const struct bpf_reg_state *ptr_reg,
10993 			      u32 *alu_limit, bool mask_to_left)
10994 {
10995 	u32 max = 0, ptr_limit = 0;
10996 
10997 	switch (ptr_reg->type) {
10998 	case PTR_TO_STACK:
10999 		/* Offset 0 is out-of-bounds, but acceptable start for the
11000 		 * left direction, see BPF_REG_FP. Also, unknown scalar
11001 		 * offset where we would need to deal with min/max bounds is
11002 		 * currently prohibited for unprivileged.
11003 		 */
11004 		max = MAX_BPF_STACK + mask_to_left;
11005 		ptr_limit = -(ptr_reg->var_off.value + ptr_reg->off);
11006 		break;
11007 	case PTR_TO_MAP_VALUE:
11008 		max = ptr_reg->map_ptr->value_size;
11009 		ptr_limit = (mask_to_left ?
11010 			     ptr_reg->smin_value :
11011 			     ptr_reg->umax_value) + ptr_reg->off;
11012 		break;
11013 	default:
11014 		return REASON_TYPE;
11015 	}
11016 
11017 	if (ptr_limit >= max)
11018 		return REASON_LIMIT;
11019 	*alu_limit = ptr_limit;
11020 	return 0;
11021 }
11022 
11023 static bool can_skip_alu_sanitation(const struct bpf_verifier_env *env,
11024 				    const struct bpf_insn *insn)
11025 {
11026 	return env->bypass_spec_v1 || BPF_SRC(insn->code) == BPF_K;
11027 }
11028 
11029 static int update_alu_sanitation_state(struct bpf_insn_aux_data *aux,
11030 				       u32 alu_state, u32 alu_limit)
11031 {
11032 	/* If we arrived here from different branches with different
11033 	 * state or limits to sanitize, then this won't work.
11034 	 */
11035 	if (aux->alu_state &&
11036 	    (aux->alu_state != alu_state ||
11037 	     aux->alu_limit != alu_limit))
11038 		return REASON_PATHS;
11039 
11040 	/* Corresponding fixup done in do_misc_fixups(). */
11041 	aux->alu_state = alu_state;
11042 	aux->alu_limit = alu_limit;
11043 	return 0;
11044 }
11045 
11046 static int sanitize_val_alu(struct bpf_verifier_env *env,
11047 			    struct bpf_insn *insn)
11048 {
11049 	struct bpf_insn_aux_data *aux = cur_aux(env);
11050 
11051 	if (can_skip_alu_sanitation(env, insn))
11052 		return 0;
11053 
11054 	return update_alu_sanitation_state(aux, BPF_ALU_NON_POINTER, 0);
11055 }
11056 
11057 static bool sanitize_needed(u8 opcode)
11058 {
11059 	return opcode == BPF_ADD || opcode == BPF_SUB;
11060 }
11061 
11062 struct bpf_sanitize_info {
11063 	struct bpf_insn_aux_data aux;
11064 	bool mask_to_left;
11065 };
11066 
11067 static struct bpf_verifier_state *
11068 sanitize_speculative_path(struct bpf_verifier_env *env,
11069 			  const struct bpf_insn *insn,
11070 			  u32 next_idx, u32 curr_idx)
11071 {
11072 	struct bpf_verifier_state *branch;
11073 	struct bpf_reg_state *regs;
11074 
11075 	branch = push_stack(env, next_idx, curr_idx, true);
11076 	if (branch && insn) {
11077 		regs = branch->frame[branch->curframe]->regs;
11078 		if (BPF_SRC(insn->code) == BPF_K) {
11079 			mark_reg_unknown(env, regs, insn->dst_reg);
11080 		} else if (BPF_SRC(insn->code) == BPF_X) {
11081 			mark_reg_unknown(env, regs, insn->dst_reg);
11082 			mark_reg_unknown(env, regs, insn->src_reg);
11083 		}
11084 	}
11085 	return branch;
11086 }
11087 
11088 static int sanitize_ptr_alu(struct bpf_verifier_env *env,
11089 			    struct bpf_insn *insn,
11090 			    const struct bpf_reg_state *ptr_reg,
11091 			    const struct bpf_reg_state *off_reg,
11092 			    struct bpf_reg_state *dst_reg,
11093 			    struct bpf_sanitize_info *info,
11094 			    const bool commit_window)
11095 {
11096 	struct bpf_insn_aux_data *aux = commit_window ? cur_aux(env) : &info->aux;
11097 	struct bpf_verifier_state *vstate = env->cur_state;
11098 	bool off_is_imm = tnum_is_const(off_reg->var_off);
11099 	bool off_is_neg = off_reg->smin_value < 0;
11100 	bool ptr_is_dst_reg = ptr_reg == dst_reg;
11101 	u8 opcode = BPF_OP(insn->code);
11102 	u32 alu_state, alu_limit;
11103 	struct bpf_reg_state tmp;
11104 	bool ret;
11105 	int err;
11106 
11107 	if (can_skip_alu_sanitation(env, insn))
11108 		return 0;
11109 
11110 	/* We already marked aux for masking from non-speculative
11111 	 * paths, thus we got here in the first place. We only care
11112 	 * to explore bad access from here.
11113 	 */
11114 	if (vstate->speculative)
11115 		goto do_sim;
11116 
11117 	if (!commit_window) {
11118 		if (!tnum_is_const(off_reg->var_off) &&
11119 		    (off_reg->smin_value < 0) != (off_reg->smax_value < 0))
11120 			return REASON_BOUNDS;
11121 
11122 		info->mask_to_left = (opcode == BPF_ADD &&  off_is_neg) ||
11123 				     (opcode == BPF_SUB && !off_is_neg);
11124 	}
11125 
11126 	err = retrieve_ptr_limit(ptr_reg, &alu_limit, info->mask_to_left);
11127 	if (err < 0)
11128 		return err;
11129 
11130 	if (commit_window) {
11131 		/* In commit phase we narrow the masking window based on
11132 		 * the observed pointer move after the simulated operation.
11133 		 */
11134 		alu_state = info->aux.alu_state;
11135 		alu_limit = abs(info->aux.alu_limit - alu_limit);
11136 	} else {
11137 		alu_state  = off_is_neg ? BPF_ALU_NEG_VALUE : 0;
11138 		alu_state |= off_is_imm ? BPF_ALU_IMMEDIATE : 0;
11139 		alu_state |= ptr_is_dst_reg ?
11140 			     BPF_ALU_SANITIZE_SRC : BPF_ALU_SANITIZE_DST;
11141 
11142 		/* Limit pruning on unknown scalars to enable deep search for
11143 		 * potential masking differences from other program paths.
11144 		 */
11145 		if (!off_is_imm)
11146 			env->explore_alu_limits = true;
11147 	}
11148 
11149 	err = update_alu_sanitation_state(aux, alu_state, alu_limit);
11150 	if (err < 0)
11151 		return err;
11152 do_sim:
11153 	/* If we're in commit phase, we're done here given we already
11154 	 * pushed the truncated dst_reg into the speculative verification
11155 	 * stack.
11156 	 *
11157 	 * Also, when register is a known constant, we rewrite register-based
11158 	 * operation to immediate-based, and thus do not need masking (and as
11159 	 * a consequence, do not need to simulate the zero-truncation either).
11160 	 */
11161 	if (commit_window || off_is_imm)
11162 		return 0;
11163 
11164 	/* Simulate and find potential out-of-bounds access under
11165 	 * speculative execution from truncation as a result of
11166 	 * masking when off was not within expected range. If off
11167 	 * sits in dst, then we temporarily need to move ptr there
11168 	 * to simulate dst (== 0) +/-= ptr. Needed, for example,
11169 	 * for cases where we use K-based arithmetic in one direction
11170 	 * and truncated reg-based in the other in order to explore
11171 	 * bad access.
11172 	 */
11173 	if (!ptr_is_dst_reg) {
11174 		tmp = *dst_reg;
11175 		copy_register_state(dst_reg, ptr_reg);
11176 	}
11177 	ret = sanitize_speculative_path(env, NULL, env->insn_idx + 1,
11178 					env->insn_idx);
11179 	if (!ptr_is_dst_reg && ret)
11180 		*dst_reg = tmp;
11181 	return !ret ? REASON_STACK : 0;
11182 }
11183 
11184 static void sanitize_mark_insn_seen(struct bpf_verifier_env *env)
11185 {
11186 	struct bpf_verifier_state *vstate = env->cur_state;
11187 
11188 	/* If we simulate paths under speculation, we don't update the
11189 	 * insn as 'seen' such that when we verify unreachable paths in
11190 	 * the non-speculative domain, sanitize_dead_code() can still
11191 	 * rewrite/sanitize them.
11192 	 */
11193 	if (!vstate->speculative)
11194 		env->insn_aux_data[env->insn_idx].seen = env->pass_cnt;
11195 }
11196 
11197 static int sanitize_err(struct bpf_verifier_env *env,
11198 			const struct bpf_insn *insn, int reason,
11199 			const struct bpf_reg_state *off_reg,
11200 			const struct bpf_reg_state *dst_reg)
11201 {
11202 	static const char *err = "pointer arithmetic with it prohibited for !root";
11203 	const char *op = BPF_OP(insn->code) == BPF_ADD ? "add" : "sub";
11204 	u32 dst = insn->dst_reg, src = insn->src_reg;
11205 
11206 	switch (reason) {
11207 	case REASON_BOUNDS:
11208 		verbose(env, "R%d has unknown scalar with mixed signed bounds, %s\n",
11209 			off_reg == dst_reg ? dst : src, err);
11210 		break;
11211 	case REASON_TYPE:
11212 		verbose(env, "R%d has pointer with unsupported alu operation, %s\n",
11213 			off_reg == dst_reg ? src : dst, err);
11214 		break;
11215 	case REASON_PATHS:
11216 		verbose(env, "R%d tried to %s from different maps, paths or scalars, %s\n",
11217 			dst, op, err);
11218 		break;
11219 	case REASON_LIMIT:
11220 		verbose(env, "R%d tried to %s beyond pointer bounds, %s\n",
11221 			dst, op, err);
11222 		break;
11223 	case REASON_STACK:
11224 		verbose(env, "R%d could not be pushed for speculative verification, %s\n",
11225 			dst, err);
11226 		break;
11227 	default:
11228 		verbose(env, "verifier internal error: unknown reason (%d)\n",
11229 			reason);
11230 		break;
11231 	}
11232 
11233 	return -EACCES;
11234 }
11235 
11236 /* check that stack access falls within stack limits and that 'reg' doesn't
11237  * have a variable offset.
11238  *
11239  * Variable offset is prohibited for unprivileged mode for simplicity since it
11240  * requires corresponding support in Spectre masking for stack ALU.  See also
11241  * retrieve_ptr_limit().
11242  *
11243  *
11244  * 'off' includes 'reg->off'.
11245  */
11246 static int check_stack_access_for_ptr_arithmetic(
11247 				struct bpf_verifier_env *env,
11248 				int regno,
11249 				const struct bpf_reg_state *reg,
11250 				int off)
11251 {
11252 	if (!tnum_is_const(reg->var_off)) {
11253 		char tn_buf[48];
11254 
11255 		tnum_strn(tn_buf, sizeof(tn_buf), reg->var_off);
11256 		verbose(env, "R%d variable stack access prohibited for !root, var_off=%s off=%d\n",
11257 			regno, tn_buf, off);
11258 		return -EACCES;
11259 	}
11260 
11261 	if (off >= 0 || off < -MAX_BPF_STACK) {
11262 		verbose(env, "R%d stack pointer arithmetic goes out of range, "
11263 			"prohibited for !root; off=%d\n", regno, off);
11264 		return -EACCES;
11265 	}
11266 
11267 	return 0;
11268 }
11269 
11270 static int sanitize_check_bounds(struct bpf_verifier_env *env,
11271 				 const struct bpf_insn *insn,
11272 				 const struct bpf_reg_state *dst_reg)
11273 {
11274 	u32 dst = insn->dst_reg;
11275 
11276 	/* For unprivileged we require that resulting offset must be in bounds
11277 	 * in order to be able to sanitize access later on.
11278 	 */
11279 	if (env->bypass_spec_v1)
11280 		return 0;
11281 
11282 	switch (dst_reg->type) {
11283 	case PTR_TO_STACK:
11284 		if (check_stack_access_for_ptr_arithmetic(env, dst, dst_reg,
11285 					dst_reg->off + dst_reg->var_off.value))
11286 			return -EACCES;
11287 		break;
11288 	case PTR_TO_MAP_VALUE:
11289 		if (check_map_access(env, dst, dst_reg->off, 1, false, ACCESS_HELPER)) {
11290 			verbose(env, "R%d pointer arithmetic of map value goes out of range, "
11291 				"prohibited for !root\n", dst);
11292 			return -EACCES;
11293 		}
11294 		break;
11295 	default:
11296 		break;
11297 	}
11298 
11299 	return 0;
11300 }
11301 
11302 /* Handles arithmetic on a pointer and a scalar: computes new min/max and var_off.
11303  * Caller should also handle BPF_MOV case separately.
11304  * If we return -EACCES, caller may want to try again treating pointer as a
11305  * scalar.  So we only emit a diagnostic if !env->allow_ptr_leaks.
11306  */
11307 static int adjust_ptr_min_max_vals(struct bpf_verifier_env *env,
11308 				   struct bpf_insn *insn,
11309 				   const struct bpf_reg_state *ptr_reg,
11310 				   const struct bpf_reg_state *off_reg)
11311 {
11312 	struct bpf_verifier_state *vstate = env->cur_state;
11313 	struct bpf_func_state *state = vstate->frame[vstate->curframe];
11314 	struct bpf_reg_state *regs = state->regs, *dst_reg;
11315 	bool known = tnum_is_const(off_reg->var_off);
11316 	s64 smin_val = off_reg->smin_value, smax_val = off_reg->smax_value,
11317 	    smin_ptr = ptr_reg->smin_value, smax_ptr = ptr_reg->smax_value;
11318 	u64 umin_val = off_reg->umin_value, umax_val = off_reg->umax_value,
11319 	    umin_ptr = ptr_reg->umin_value, umax_ptr = ptr_reg->umax_value;
11320 	struct bpf_sanitize_info info = {};
11321 	u8 opcode = BPF_OP(insn->code);
11322 	u32 dst = insn->dst_reg;
11323 	int ret;
11324 
11325 	dst_reg = &regs[dst];
11326 
11327 	if ((known && (smin_val != smax_val || umin_val != umax_val)) ||
11328 	    smin_val > smax_val || umin_val > umax_val) {
11329 		/* Taint dst register if offset had invalid bounds derived from
11330 		 * e.g. dead branches.
11331 		 */
11332 		__mark_reg_unknown(env, dst_reg);
11333 		return 0;
11334 	}
11335 
11336 	if (BPF_CLASS(insn->code) != BPF_ALU64) {
11337 		/* 32-bit ALU ops on pointers produce (meaningless) scalars */
11338 		if (opcode == BPF_SUB && env->allow_ptr_leaks) {
11339 			__mark_reg_unknown(env, dst_reg);
11340 			return 0;
11341 		}
11342 
11343 		verbose(env,
11344 			"R%d 32-bit pointer arithmetic prohibited\n",
11345 			dst);
11346 		return -EACCES;
11347 	}
11348 
11349 	if (ptr_reg->type & PTR_MAYBE_NULL) {
11350 		verbose(env, "R%d pointer arithmetic on %s prohibited, null-check it first\n",
11351 			dst, reg_type_str(env, ptr_reg->type));
11352 		return -EACCES;
11353 	}
11354 
11355 	switch (base_type(ptr_reg->type)) {
11356 	case CONST_PTR_TO_MAP:
11357 		/* smin_val represents the known value */
11358 		if (known && smin_val == 0 && opcode == BPF_ADD)
11359 			break;
11360 		fallthrough;
11361 	case PTR_TO_PACKET_END:
11362 	case PTR_TO_SOCKET:
11363 	case PTR_TO_SOCK_COMMON:
11364 	case PTR_TO_TCP_SOCK:
11365 	case PTR_TO_XDP_SOCK:
11366 		verbose(env, "R%d pointer arithmetic on %s prohibited\n",
11367 			dst, reg_type_str(env, ptr_reg->type));
11368 		return -EACCES;
11369 	default:
11370 		break;
11371 	}
11372 
11373 	/* In case of 'scalar += pointer', dst_reg inherits pointer type and id.
11374 	 * The id may be overwritten later if we create a new variable offset.
11375 	 */
11376 	dst_reg->type = ptr_reg->type;
11377 	dst_reg->id = ptr_reg->id;
11378 
11379 	if (!check_reg_sane_offset(env, off_reg, ptr_reg->type) ||
11380 	    !check_reg_sane_offset(env, ptr_reg, ptr_reg->type))
11381 		return -EINVAL;
11382 
11383 	/* pointer types do not carry 32-bit bounds at the moment. */
11384 	__mark_reg32_unbounded(dst_reg);
11385 
11386 	if (sanitize_needed(opcode)) {
11387 		ret = sanitize_ptr_alu(env, insn, ptr_reg, off_reg, dst_reg,
11388 				       &info, false);
11389 		if (ret < 0)
11390 			return sanitize_err(env, insn, ret, off_reg, dst_reg);
11391 	}
11392 
11393 	switch (opcode) {
11394 	case BPF_ADD:
11395 		/* We can take a fixed offset as long as it doesn't overflow
11396 		 * the s32 'off' field
11397 		 */
11398 		if (known && (ptr_reg->off + smin_val ==
11399 			      (s64)(s32)(ptr_reg->off + smin_val))) {
11400 			/* pointer += K.  Accumulate it into fixed offset */
11401 			dst_reg->smin_value = smin_ptr;
11402 			dst_reg->smax_value = smax_ptr;
11403 			dst_reg->umin_value = umin_ptr;
11404 			dst_reg->umax_value = umax_ptr;
11405 			dst_reg->var_off = ptr_reg->var_off;
11406 			dst_reg->off = ptr_reg->off + smin_val;
11407 			dst_reg->raw = ptr_reg->raw;
11408 			break;
11409 		}
11410 		/* A new variable offset is created.  Note that off_reg->off
11411 		 * == 0, since it's a scalar.
11412 		 * dst_reg gets the pointer type and since some positive
11413 		 * integer value was added to the pointer, give it a new 'id'
11414 		 * if it's a PTR_TO_PACKET.
11415 		 * this creates a new 'base' pointer, off_reg (variable) gets
11416 		 * added into the variable offset, and we copy the fixed offset
11417 		 * from ptr_reg.
11418 		 */
11419 		if (signed_add_overflows(smin_ptr, smin_val) ||
11420 		    signed_add_overflows(smax_ptr, smax_val)) {
11421 			dst_reg->smin_value = S64_MIN;
11422 			dst_reg->smax_value = S64_MAX;
11423 		} else {
11424 			dst_reg->smin_value = smin_ptr + smin_val;
11425 			dst_reg->smax_value = smax_ptr + smax_val;
11426 		}
11427 		if (umin_ptr + umin_val < umin_ptr ||
11428 		    umax_ptr + umax_val < umax_ptr) {
11429 			dst_reg->umin_value = 0;
11430 			dst_reg->umax_value = U64_MAX;
11431 		} else {
11432 			dst_reg->umin_value = umin_ptr + umin_val;
11433 			dst_reg->umax_value = umax_ptr + umax_val;
11434 		}
11435 		dst_reg->var_off = tnum_add(ptr_reg->var_off, off_reg->var_off);
11436 		dst_reg->off = ptr_reg->off;
11437 		dst_reg->raw = ptr_reg->raw;
11438 		if (reg_is_pkt_pointer(ptr_reg)) {
11439 			dst_reg->id = ++env->id_gen;
11440 			/* something was added to pkt_ptr, set range to zero */
11441 			memset(&dst_reg->raw, 0, sizeof(dst_reg->raw));
11442 		}
11443 		break;
11444 	case BPF_SUB:
11445 		if (dst_reg == off_reg) {
11446 			/* scalar -= pointer.  Creates an unknown scalar */
11447 			verbose(env, "R%d tried to subtract pointer from scalar\n",
11448 				dst);
11449 			return -EACCES;
11450 		}
11451 		/* We don't allow subtraction from FP, because (according to
11452 		 * test_verifier.c test "invalid fp arithmetic", JITs might not
11453 		 * be able to deal with it.
11454 		 */
11455 		if (ptr_reg->type == PTR_TO_STACK) {
11456 			verbose(env, "R%d subtraction from stack pointer prohibited\n",
11457 				dst);
11458 			return -EACCES;
11459 		}
11460 		if (known && (ptr_reg->off - smin_val ==
11461 			      (s64)(s32)(ptr_reg->off - smin_val))) {
11462 			/* pointer -= K.  Subtract it from fixed offset */
11463 			dst_reg->smin_value = smin_ptr;
11464 			dst_reg->smax_value = smax_ptr;
11465 			dst_reg->umin_value = umin_ptr;
11466 			dst_reg->umax_value = umax_ptr;
11467 			dst_reg->var_off = ptr_reg->var_off;
11468 			dst_reg->id = ptr_reg->id;
11469 			dst_reg->off = ptr_reg->off - smin_val;
11470 			dst_reg->raw = ptr_reg->raw;
11471 			break;
11472 		}
11473 		/* A new variable offset is created.  If the subtrahend is known
11474 		 * nonnegative, then any reg->range we had before is still good.
11475 		 */
11476 		if (signed_sub_overflows(smin_ptr, smax_val) ||
11477 		    signed_sub_overflows(smax_ptr, smin_val)) {
11478 			/* Overflow possible, we know nothing */
11479 			dst_reg->smin_value = S64_MIN;
11480 			dst_reg->smax_value = S64_MAX;
11481 		} else {
11482 			dst_reg->smin_value = smin_ptr - smax_val;
11483 			dst_reg->smax_value = smax_ptr - smin_val;
11484 		}
11485 		if (umin_ptr < umax_val) {
11486 			/* Overflow possible, we know nothing */
11487 			dst_reg->umin_value = 0;
11488 			dst_reg->umax_value = U64_MAX;
11489 		} else {
11490 			/* Cannot overflow (as long as bounds are consistent) */
11491 			dst_reg->umin_value = umin_ptr - umax_val;
11492 			dst_reg->umax_value = umax_ptr - umin_val;
11493 		}
11494 		dst_reg->var_off = tnum_sub(ptr_reg->var_off, off_reg->var_off);
11495 		dst_reg->off = ptr_reg->off;
11496 		dst_reg->raw = ptr_reg->raw;
11497 		if (reg_is_pkt_pointer(ptr_reg)) {
11498 			dst_reg->id = ++env->id_gen;
11499 			/* something was added to pkt_ptr, set range to zero */
11500 			if (smin_val < 0)
11501 				memset(&dst_reg->raw, 0, sizeof(dst_reg->raw));
11502 		}
11503 		break;
11504 	case BPF_AND:
11505 	case BPF_OR:
11506 	case BPF_XOR:
11507 		/* bitwise ops on pointers are troublesome, prohibit. */
11508 		verbose(env, "R%d bitwise operator %s on pointer prohibited\n",
11509 			dst, bpf_alu_string[opcode >> 4]);
11510 		return -EACCES;
11511 	default:
11512 		/* other operators (e.g. MUL,LSH) produce non-pointer results */
11513 		verbose(env, "R%d pointer arithmetic with %s operator prohibited\n",
11514 			dst, bpf_alu_string[opcode >> 4]);
11515 		return -EACCES;
11516 	}
11517 
11518 	if (!check_reg_sane_offset(env, dst_reg, ptr_reg->type))
11519 		return -EINVAL;
11520 	reg_bounds_sync(dst_reg);
11521 	if (sanitize_check_bounds(env, insn, dst_reg) < 0)
11522 		return -EACCES;
11523 	if (sanitize_needed(opcode)) {
11524 		ret = sanitize_ptr_alu(env, insn, dst_reg, off_reg, dst_reg,
11525 				       &info, true);
11526 		if (ret < 0)
11527 			return sanitize_err(env, insn, ret, off_reg, dst_reg);
11528 	}
11529 
11530 	return 0;
11531 }
11532 
11533 static void scalar32_min_max_add(struct bpf_reg_state *dst_reg,
11534 				 struct bpf_reg_state *src_reg)
11535 {
11536 	s32 smin_val = src_reg->s32_min_value;
11537 	s32 smax_val = src_reg->s32_max_value;
11538 	u32 umin_val = src_reg->u32_min_value;
11539 	u32 umax_val = src_reg->u32_max_value;
11540 
11541 	if (signed_add32_overflows(dst_reg->s32_min_value, smin_val) ||
11542 	    signed_add32_overflows(dst_reg->s32_max_value, smax_val)) {
11543 		dst_reg->s32_min_value = S32_MIN;
11544 		dst_reg->s32_max_value = S32_MAX;
11545 	} else {
11546 		dst_reg->s32_min_value += smin_val;
11547 		dst_reg->s32_max_value += smax_val;
11548 	}
11549 	if (dst_reg->u32_min_value + umin_val < umin_val ||
11550 	    dst_reg->u32_max_value + umax_val < umax_val) {
11551 		dst_reg->u32_min_value = 0;
11552 		dst_reg->u32_max_value = U32_MAX;
11553 	} else {
11554 		dst_reg->u32_min_value += umin_val;
11555 		dst_reg->u32_max_value += umax_val;
11556 	}
11557 }
11558 
11559 static void scalar_min_max_add(struct bpf_reg_state *dst_reg,
11560 			       struct bpf_reg_state *src_reg)
11561 {
11562 	s64 smin_val = src_reg->smin_value;
11563 	s64 smax_val = src_reg->smax_value;
11564 	u64 umin_val = src_reg->umin_value;
11565 	u64 umax_val = src_reg->umax_value;
11566 
11567 	if (signed_add_overflows(dst_reg->smin_value, smin_val) ||
11568 	    signed_add_overflows(dst_reg->smax_value, smax_val)) {
11569 		dst_reg->smin_value = S64_MIN;
11570 		dst_reg->smax_value = S64_MAX;
11571 	} else {
11572 		dst_reg->smin_value += smin_val;
11573 		dst_reg->smax_value += smax_val;
11574 	}
11575 	if (dst_reg->umin_value + umin_val < umin_val ||
11576 	    dst_reg->umax_value + umax_val < umax_val) {
11577 		dst_reg->umin_value = 0;
11578 		dst_reg->umax_value = U64_MAX;
11579 	} else {
11580 		dst_reg->umin_value += umin_val;
11581 		dst_reg->umax_value += umax_val;
11582 	}
11583 }
11584 
11585 static void scalar32_min_max_sub(struct bpf_reg_state *dst_reg,
11586 				 struct bpf_reg_state *src_reg)
11587 {
11588 	s32 smin_val = src_reg->s32_min_value;
11589 	s32 smax_val = src_reg->s32_max_value;
11590 	u32 umin_val = src_reg->u32_min_value;
11591 	u32 umax_val = src_reg->u32_max_value;
11592 
11593 	if (signed_sub32_overflows(dst_reg->s32_min_value, smax_val) ||
11594 	    signed_sub32_overflows(dst_reg->s32_max_value, smin_val)) {
11595 		/* Overflow possible, we know nothing */
11596 		dst_reg->s32_min_value = S32_MIN;
11597 		dst_reg->s32_max_value = S32_MAX;
11598 	} else {
11599 		dst_reg->s32_min_value -= smax_val;
11600 		dst_reg->s32_max_value -= smin_val;
11601 	}
11602 	if (dst_reg->u32_min_value < umax_val) {
11603 		/* Overflow possible, we know nothing */
11604 		dst_reg->u32_min_value = 0;
11605 		dst_reg->u32_max_value = U32_MAX;
11606 	} else {
11607 		/* Cannot overflow (as long as bounds are consistent) */
11608 		dst_reg->u32_min_value -= umax_val;
11609 		dst_reg->u32_max_value -= umin_val;
11610 	}
11611 }
11612 
11613 static void scalar_min_max_sub(struct bpf_reg_state *dst_reg,
11614 			       struct bpf_reg_state *src_reg)
11615 {
11616 	s64 smin_val = src_reg->smin_value;
11617 	s64 smax_val = src_reg->smax_value;
11618 	u64 umin_val = src_reg->umin_value;
11619 	u64 umax_val = src_reg->umax_value;
11620 
11621 	if (signed_sub_overflows(dst_reg->smin_value, smax_val) ||
11622 	    signed_sub_overflows(dst_reg->smax_value, smin_val)) {
11623 		/* Overflow possible, we know nothing */
11624 		dst_reg->smin_value = S64_MIN;
11625 		dst_reg->smax_value = S64_MAX;
11626 	} else {
11627 		dst_reg->smin_value -= smax_val;
11628 		dst_reg->smax_value -= smin_val;
11629 	}
11630 	if (dst_reg->umin_value < umax_val) {
11631 		/* Overflow possible, we know nothing */
11632 		dst_reg->umin_value = 0;
11633 		dst_reg->umax_value = U64_MAX;
11634 	} else {
11635 		/* Cannot overflow (as long as bounds are consistent) */
11636 		dst_reg->umin_value -= umax_val;
11637 		dst_reg->umax_value -= umin_val;
11638 	}
11639 }
11640 
11641 static void scalar32_min_max_mul(struct bpf_reg_state *dst_reg,
11642 				 struct bpf_reg_state *src_reg)
11643 {
11644 	s32 smin_val = src_reg->s32_min_value;
11645 	u32 umin_val = src_reg->u32_min_value;
11646 	u32 umax_val = src_reg->u32_max_value;
11647 
11648 	if (smin_val < 0 || dst_reg->s32_min_value < 0) {
11649 		/* Ain't nobody got time to multiply that sign */
11650 		__mark_reg32_unbounded(dst_reg);
11651 		return;
11652 	}
11653 	/* Both values are positive, so we can work with unsigned and
11654 	 * copy the result to signed (unless it exceeds S32_MAX).
11655 	 */
11656 	if (umax_val > U16_MAX || dst_reg->u32_max_value > U16_MAX) {
11657 		/* Potential overflow, we know nothing */
11658 		__mark_reg32_unbounded(dst_reg);
11659 		return;
11660 	}
11661 	dst_reg->u32_min_value *= umin_val;
11662 	dst_reg->u32_max_value *= umax_val;
11663 	if (dst_reg->u32_max_value > S32_MAX) {
11664 		/* Overflow possible, we know nothing */
11665 		dst_reg->s32_min_value = S32_MIN;
11666 		dst_reg->s32_max_value = S32_MAX;
11667 	} else {
11668 		dst_reg->s32_min_value = dst_reg->u32_min_value;
11669 		dst_reg->s32_max_value = dst_reg->u32_max_value;
11670 	}
11671 }
11672 
11673 static void scalar_min_max_mul(struct bpf_reg_state *dst_reg,
11674 			       struct bpf_reg_state *src_reg)
11675 {
11676 	s64 smin_val = src_reg->smin_value;
11677 	u64 umin_val = src_reg->umin_value;
11678 	u64 umax_val = src_reg->umax_value;
11679 
11680 	if (smin_val < 0 || dst_reg->smin_value < 0) {
11681 		/* Ain't nobody got time to multiply that sign */
11682 		__mark_reg64_unbounded(dst_reg);
11683 		return;
11684 	}
11685 	/* Both values are positive, so we can work with unsigned and
11686 	 * copy the result to signed (unless it exceeds S64_MAX).
11687 	 */
11688 	if (umax_val > U32_MAX || dst_reg->umax_value > U32_MAX) {
11689 		/* Potential overflow, we know nothing */
11690 		__mark_reg64_unbounded(dst_reg);
11691 		return;
11692 	}
11693 	dst_reg->umin_value *= umin_val;
11694 	dst_reg->umax_value *= umax_val;
11695 	if (dst_reg->umax_value > S64_MAX) {
11696 		/* Overflow possible, we know nothing */
11697 		dst_reg->smin_value = S64_MIN;
11698 		dst_reg->smax_value = S64_MAX;
11699 	} else {
11700 		dst_reg->smin_value = dst_reg->umin_value;
11701 		dst_reg->smax_value = dst_reg->umax_value;
11702 	}
11703 }
11704 
11705 static void scalar32_min_max_and(struct bpf_reg_state *dst_reg,
11706 				 struct bpf_reg_state *src_reg)
11707 {
11708 	bool src_known = tnum_subreg_is_const(src_reg->var_off);
11709 	bool dst_known = tnum_subreg_is_const(dst_reg->var_off);
11710 	struct tnum var32_off = tnum_subreg(dst_reg->var_off);
11711 	s32 smin_val = src_reg->s32_min_value;
11712 	u32 umax_val = src_reg->u32_max_value;
11713 
11714 	if (src_known && dst_known) {
11715 		__mark_reg32_known(dst_reg, var32_off.value);
11716 		return;
11717 	}
11718 
11719 	/* We get our minimum from the var_off, since that's inherently
11720 	 * bitwise.  Our maximum is the minimum of the operands' maxima.
11721 	 */
11722 	dst_reg->u32_min_value = var32_off.value;
11723 	dst_reg->u32_max_value = min(dst_reg->u32_max_value, umax_val);
11724 	if (dst_reg->s32_min_value < 0 || smin_val < 0) {
11725 		/* Lose signed bounds when ANDing negative numbers,
11726 		 * ain't nobody got time for that.
11727 		 */
11728 		dst_reg->s32_min_value = S32_MIN;
11729 		dst_reg->s32_max_value = S32_MAX;
11730 	} else {
11731 		/* ANDing two positives gives a positive, so safe to
11732 		 * cast result into s64.
11733 		 */
11734 		dst_reg->s32_min_value = dst_reg->u32_min_value;
11735 		dst_reg->s32_max_value = dst_reg->u32_max_value;
11736 	}
11737 }
11738 
11739 static void scalar_min_max_and(struct bpf_reg_state *dst_reg,
11740 			       struct bpf_reg_state *src_reg)
11741 {
11742 	bool src_known = tnum_is_const(src_reg->var_off);
11743 	bool dst_known = tnum_is_const(dst_reg->var_off);
11744 	s64 smin_val = src_reg->smin_value;
11745 	u64 umax_val = src_reg->umax_value;
11746 
11747 	if (src_known && dst_known) {
11748 		__mark_reg_known(dst_reg, dst_reg->var_off.value);
11749 		return;
11750 	}
11751 
11752 	/* We get our minimum from the var_off, since that's inherently
11753 	 * bitwise.  Our maximum is the minimum of the operands' maxima.
11754 	 */
11755 	dst_reg->umin_value = dst_reg->var_off.value;
11756 	dst_reg->umax_value = min(dst_reg->umax_value, umax_val);
11757 	if (dst_reg->smin_value < 0 || smin_val < 0) {
11758 		/* Lose signed bounds when ANDing negative numbers,
11759 		 * ain't nobody got time for that.
11760 		 */
11761 		dst_reg->smin_value = S64_MIN;
11762 		dst_reg->smax_value = S64_MAX;
11763 	} else {
11764 		/* ANDing two positives gives a positive, so safe to
11765 		 * cast result into s64.
11766 		 */
11767 		dst_reg->smin_value = dst_reg->umin_value;
11768 		dst_reg->smax_value = dst_reg->umax_value;
11769 	}
11770 	/* We may learn something more from the var_off */
11771 	__update_reg_bounds(dst_reg);
11772 }
11773 
11774 static void scalar32_min_max_or(struct bpf_reg_state *dst_reg,
11775 				struct bpf_reg_state *src_reg)
11776 {
11777 	bool src_known = tnum_subreg_is_const(src_reg->var_off);
11778 	bool dst_known = tnum_subreg_is_const(dst_reg->var_off);
11779 	struct tnum var32_off = tnum_subreg(dst_reg->var_off);
11780 	s32 smin_val = src_reg->s32_min_value;
11781 	u32 umin_val = src_reg->u32_min_value;
11782 
11783 	if (src_known && dst_known) {
11784 		__mark_reg32_known(dst_reg, var32_off.value);
11785 		return;
11786 	}
11787 
11788 	/* We get our maximum from the var_off, and our minimum is the
11789 	 * maximum of the operands' minima
11790 	 */
11791 	dst_reg->u32_min_value = max(dst_reg->u32_min_value, umin_val);
11792 	dst_reg->u32_max_value = var32_off.value | var32_off.mask;
11793 	if (dst_reg->s32_min_value < 0 || smin_val < 0) {
11794 		/* Lose signed bounds when ORing negative numbers,
11795 		 * ain't nobody got time for that.
11796 		 */
11797 		dst_reg->s32_min_value = S32_MIN;
11798 		dst_reg->s32_max_value = S32_MAX;
11799 	} else {
11800 		/* ORing two positives gives a positive, so safe to
11801 		 * cast result into s64.
11802 		 */
11803 		dst_reg->s32_min_value = dst_reg->u32_min_value;
11804 		dst_reg->s32_max_value = dst_reg->u32_max_value;
11805 	}
11806 }
11807 
11808 static void scalar_min_max_or(struct bpf_reg_state *dst_reg,
11809 			      struct bpf_reg_state *src_reg)
11810 {
11811 	bool src_known = tnum_is_const(src_reg->var_off);
11812 	bool dst_known = tnum_is_const(dst_reg->var_off);
11813 	s64 smin_val = src_reg->smin_value;
11814 	u64 umin_val = src_reg->umin_value;
11815 
11816 	if (src_known && dst_known) {
11817 		__mark_reg_known(dst_reg, dst_reg->var_off.value);
11818 		return;
11819 	}
11820 
11821 	/* We get our maximum from the var_off, and our minimum is the
11822 	 * maximum of the operands' minima
11823 	 */
11824 	dst_reg->umin_value = max(dst_reg->umin_value, umin_val);
11825 	dst_reg->umax_value = dst_reg->var_off.value | dst_reg->var_off.mask;
11826 	if (dst_reg->smin_value < 0 || smin_val < 0) {
11827 		/* Lose signed bounds when ORing negative numbers,
11828 		 * ain't nobody got time for that.
11829 		 */
11830 		dst_reg->smin_value = S64_MIN;
11831 		dst_reg->smax_value = S64_MAX;
11832 	} else {
11833 		/* ORing two positives gives a positive, so safe to
11834 		 * cast result into s64.
11835 		 */
11836 		dst_reg->smin_value = dst_reg->umin_value;
11837 		dst_reg->smax_value = dst_reg->umax_value;
11838 	}
11839 	/* We may learn something more from the var_off */
11840 	__update_reg_bounds(dst_reg);
11841 }
11842 
11843 static void scalar32_min_max_xor(struct bpf_reg_state *dst_reg,
11844 				 struct bpf_reg_state *src_reg)
11845 {
11846 	bool src_known = tnum_subreg_is_const(src_reg->var_off);
11847 	bool dst_known = tnum_subreg_is_const(dst_reg->var_off);
11848 	struct tnum var32_off = tnum_subreg(dst_reg->var_off);
11849 	s32 smin_val = src_reg->s32_min_value;
11850 
11851 	if (src_known && dst_known) {
11852 		__mark_reg32_known(dst_reg, var32_off.value);
11853 		return;
11854 	}
11855 
11856 	/* We get both minimum and maximum from the var32_off. */
11857 	dst_reg->u32_min_value = var32_off.value;
11858 	dst_reg->u32_max_value = var32_off.value | var32_off.mask;
11859 
11860 	if (dst_reg->s32_min_value >= 0 && smin_val >= 0) {
11861 		/* XORing two positive sign numbers gives a positive,
11862 		 * so safe to cast u32 result into s32.
11863 		 */
11864 		dst_reg->s32_min_value = dst_reg->u32_min_value;
11865 		dst_reg->s32_max_value = dst_reg->u32_max_value;
11866 	} else {
11867 		dst_reg->s32_min_value = S32_MIN;
11868 		dst_reg->s32_max_value = S32_MAX;
11869 	}
11870 }
11871 
11872 static void scalar_min_max_xor(struct bpf_reg_state *dst_reg,
11873 			       struct bpf_reg_state *src_reg)
11874 {
11875 	bool src_known = tnum_is_const(src_reg->var_off);
11876 	bool dst_known = tnum_is_const(dst_reg->var_off);
11877 	s64 smin_val = src_reg->smin_value;
11878 
11879 	if (src_known && dst_known) {
11880 		/* dst_reg->var_off.value has been updated earlier */
11881 		__mark_reg_known(dst_reg, dst_reg->var_off.value);
11882 		return;
11883 	}
11884 
11885 	/* We get both minimum and maximum from the var_off. */
11886 	dst_reg->umin_value = dst_reg->var_off.value;
11887 	dst_reg->umax_value = dst_reg->var_off.value | dst_reg->var_off.mask;
11888 
11889 	if (dst_reg->smin_value >= 0 && smin_val >= 0) {
11890 		/* XORing two positive sign numbers gives a positive,
11891 		 * so safe to cast u64 result into s64.
11892 		 */
11893 		dst_reg->smin_value = dst_reg->umin_value;
11894 		dst_reg->smax_value = dst_reg->umax_value;
11895 	} else {
11896 		dst_reg->smin_value = S64_MIN;
11897 		dst_reg->smax_value = S64_MAX;
11898 	}
11899 
11900 	__update_reg_bounds(dst_reg);
11901 }
11902 
11903 static void __scalar32_min_max_lsh(struct bpf_reg_state *dst_reg,
11904 				   u64 umin_val, u64 umax_val)
11905 {
11906 	/* We lose all sign bit information (except what we can pick
11907 	 * up from var_off)
11908 	 */
11909 	dst_reg->s32_min_value = S32_MIN;
11910 	dst_reg->s32_max_value = S32_MAX;
11911 	/* If we might shift our top bit out, then we know nothing */
11912 	if (umax_val > 31 || dst_reg->u32_max_value > 1ULL << (31 - umax_val)) {
11913 		dst_reg->u32_min_value = 0;
11914 		dst_reg->u32_max_value = U32_MAX;
11915 	} else {
11916 		dst_reg->u32_min_value <<= umin_val;
11917 		dst_reg->u32_max_value <<= umax_val;
11918 	}
11919 }
11920 
11921 static void scalar32_min_max_lsh(struct bpf_reg_state *dst_reg,
11922 				 struct bpf_reg_state *src_reg)
11923 {
11924 	u32 umax_val = src_reg->u32_max_value;
11925 	u32 umin_val = src_reg->u32_min_value;
11926 	/* u32 alu operation will zext upper bits */
11927 	struct tnum subreg = tnum_subreg(dst_reg->var_off);
11928 
11929 	__scalar32_min_max_lsh(dst_reg, umin_val, umax_val);
11930 	dst_reg->var_off = tnum_subreg(tnum_lshift(subreg, umin_val));
11931 	/* Not required but being careful mark reg64 bounds as unknown so
11932 	 * that we are forced to pick them up from tnum and zext later and
11933 	 * if some path skips this step we are still safe.
11934 	 */
11935 	__mark_reg64_unbounded(dst_reg);
11936 	__update_reg32_bounds(dst_reg);
11937 }
11938 
11939 static void __scalar64_min_max_lsh(struct bpf_reg_state *dst_reg,
11940 				   u64 umin_val, u64 umax_val)
11941 {
11942 	/* Special case <<32 because it is a common compiler pattern to sign
11943 	 * extend subreg by doing <<32 s>>32. In this case if 32bit bounds are
11944 	 * positive we know this shift will also be positive so we can track
11945 	 * bounds correctly. Otherwise we lose all sign bit information except
11946 	 * what we can pick up from var_off. Perhaps we can generalize this
11947 	 * later to shifts of any length.
11948 	 */
11949 	if (umin_val == 32 && umax_val == 32 && dst_reg->s32_max_value >= 0)
11950 		dst_reg->smax_value = (s64)dst_reg->s32_max_value << 32;
11951 	else
11952 		dst_reg->smax_value = S64_MAX;
11953 
11954 	if (umin_val == 32 && umax_val == 32 && dst_reg->s32_min_value >= 0)
11955 		dst_reg->smin_value = (s64)dst_reg->s32_min_value << 32;
11956 	else
11957 		dst_reg->smin_value = S64_MIN;
11958 
11959 	/* If we might shift our top bit out, then we know nothing */
11960 	if (dst_reg->umax_value > 1ULL << (63 - umax_val)) {
11961 		dst_reg->umin_value = 0;
11962 		dst_reg->umax_value = U64_MAX;
11963 	} else {
11964 		dst_reg->umin_value <<= umin_val;
11965 		dst_reg->umax_value <<= umax_val;
11966 	}
11967 }
11968 
11969 static void scalar_min_max_lsh(struct bpf_reg_state *dst_reg,
11970 			       struct bpf_reg_state *src_reg)
11971 {
11972 	u64 umax_val = src_reg->umax_value;
11973 	u64 umin_val = src_reg->umin_value;
11974 
11975 	/* scalar64 calc uses 32bit unshifted bounds so must be called first */
11976 	__scalar64_min_max_lsh(dst_reg, umin_val, umax_val);
11977 	__scalar32_min_max_lsh(dst_reg, umin_val, umax_val);
11978 
11979 	dst_reg->var_off = tnum_lshift(dst_reg->var_off, umin_val);
11980 	/* We may learn something more from the var_off */
11981 	__update_reg_bounds(dst_reg);
11982 }
11983 
11984 static void scalar32_min_max_rsh(struct bpf_reg_state *dst_reg,
11985 				 struct bpf_reg_state *src_reg)
11986 {
11987 	struct tnum subreg = tnum_subreg(dst_reg->var_off);
11988 	u32 umax_val = src_reg->u32_max_value;
11989 	u32 umin_val = src_reg->u32_min_value;
11990 
11991 	/* BPF_RSH is an unsigned shift.  If the value in dst_reg might
11992 	 * be negative, then either:
11993 	 * 1) src_reg might be zero, so the sign bit of the result is
11994 	 *    unknown, so we lose our signed bounds
11995 	 * 2) it's known negative, thus the unsigned bounds capture the
11996 	 *    signed bounds
11997 	 * 3) the signed bounds cross zero, so they tell us nothing
11998 	 *    about the result
11999 	 * If the value in dst_reg is known nonnegative, then again the
12000 	 * unsigned bounds capture the signed bounds.
12001 	 * Thus, in all cases it suffices to blow away our signed bounds
12002 	 * and rely on inferring new ones from the unsigned bounds and
12003 	 * var_off of the result.
12004 	 */
12005 	dst_reg->s32_min_value = S32_MIN;
12006 	dst_reg->s32_max_value = S32_MAX;
12007 
12008 	dst_reg->var_off = tnum_rshift(subreg, umin_val);
12009 	dst_reg->u32_min_value >>= umax_val;
12010 	dst_reg->u32_max_value >>= umin_val;
12011 
12012 	__mark_reg64_unbounded(dst_reg);
12013 	__update_reg32_bounds(dst_reg);
12014 }
12015 
12016 static void scalar_min_max_rsh(struct bpf_reg_state *dst_reg,
12017 			       struct bpf_reg_state *src_reg)
12018 {
12019 	u64 umax_val = src_reg->umax_value;
12020 	u64 umin_val = src_reg->umin_value;
12021 
12022 	/* BPF_RSH is an unsigned shift.  If the value in dst_reg might
12023 	 * be negative, then either:
12024 	 * 1) src_reg might be zero, so the sign bit of the result is
12025 	 *    unknown, so we lose our signed bounds
12026 	 * 2) it's known negative, thus the unsigned bounds capture the
12027 	 *    signed bounds
12028 	 * 3) the signed bounds cross zero, so they tell us nothing
12029 	 *    about the result
12030 	 * If the value in dst_reg is known nonnegative, then again the
12031 	 * unsigned bounds capture the signed bounds.
12032 	 * Thus, in all cases it suffices to blow away our signed bounds
12033 	 * and rely on inferring new ones from the unsigned bounds and
12034 	 * var_off of the result.
12035 	 */
12036 	dst_reg->smin_value = S64_MIN;
12037 	dst_reg->smax_value = S64_MAX;
12038 	dst_reg->var_off = tnum_rshift(dst_reg->var_off, umin_val);
12039 	dst_reg->umin_value >>= umax_val;
12040 	dst_reg->umax_value >>= umin_val;
12041 
12042 	/* Its not easy to operate on alu32 bounds here because it depends
12043 	 * on bits being shifted in. Take easy way out and mark unbounded
12044 	 * so we can recalculate later from tnum.
12045 	 */
12046 	__mark_reg32_unbounded(dst_reg);
12047 	__update_reg_bounds(dst_reg);
12048 }
12049 
12050 static void scalar32_min_max_arsh(struct bpf_reg_state *dst_reg,
12051 				  struct bpf_reg_state *src_reg)
12052 {
12053 	u64 umin_val = src_reg->u32_min_value;
12054 
12055 	/* Upon reaching here, src_known is true and
12056 	 * umax_val is equal to umin_val.
12057 	 */
12058 	dst_reg->s32_min_value = (u32)(((s32)dst_reg->s32_min_value) >> umin_val);
12059 	dst_reg->s32_max_value = (u32)(((s32)dst_reg->s32_max_value) >> umin_val);
12060 
12061 	dst_reg->var_off = tnum_arshift(tnum_subreg(dst_reg->var_off), umin_val, 32);
12062 
12063 	/* blow away the dst_reg umin_value/umax_value and rely on
12064 	 * dst_reg var_off to refine the result.
12065 	 */
12066 	dst_reg->u32_min_value = 0;
12067 	dst_reg->u32_max_value = U32_MAX;
12068 
12069 	__mark_reg64_unbounded(dst_reg);
12070 	__update_reg32_bounds(dst_reg);
12071 }
12072 
12073 static void scalar_min_max_arsh(struct bpf_reg_state *dst_reg,
12074 				struct bpf_reg_state *src_reg)
12075 {
12076 	u64 umin_val = src_reg->umin_value;
12077 
12078 	/* Upon reaching here, src_known is true and umax_val is equal
12079 	 * to umin_val.
12080 	 */
12081 	dst_reg->smin_value >>= umin_val;
12082 	dst_reg->smax_value >>= umin_val;
12083 
12084 	dst_reg->var_off = tnum_arshift(dst_reg->var_off, umin_val, 64);
12085 
12086 	/* blow away the dst_reg umin_value/umax_value and rely on
12087 	 * dst_reg var_off to refine the result.
12088 	 */
12089 	dst_reg->umin_value = 0;
12090 	dst_reg->umax_value = U64_MAX;
12091 
12092 	/* Its not easy to operate on alu32 bounds here because it depends
12093 	 * on bits being shifted in from upper 32-bits. Take easy way out
12094 	 * and mark unbounded so we can recalculate later from tnum.
12095 	 */
12096 	__mark_reg32_unbounded(dst_reg);
12097 	__update_reg_bounds(dst_reg);
12098 }
12099 
12100 /* WARNING: This function does calculations on 64-bit values, but the actual
12101  * execution may occur on 32-bit values. Therefore, things like bitshifts
12102  * need extra checks in the 32-bit case.
12103  */
12104 static int adjust_scalar_min_max_vals(struct bpf_verifier_env *env,
12105 				      struct bpf_insn *insn,
12106 				      struct bpf_reg_state *dst_reg,
12107 				      struct bpf_reg_state src_reg)
12108 {
12109 	struct bpf_reg_state *regs = cur_regs(env);
12110 	u8 opcode = BPF_OP(insn->code);
12111 	bool src_known;
12112 	s64 smin_val, smax_val;
12113 	u64 umin_val, umax_val;
12114 	s32 s32_min_val, s32_max_val;
12115 	u32 u32_min_val, u32_max_val;
12116 	u64 insn_bitness = (BPF_CLASS(insn->code) == BPF_ALU64) ? 64 : 32;
12117 	bool alu32 = (BPF_CLASS(insn->code) != BPF_ALU64);
12118 	int ret;
12119 
12120 	smin_val = src_reg.smin_value;
12121 	smax_val = src_reg.smax_value;
12122 	umin_val = src_reg.umin_value;
12123 	umax_val = src_reg.umax_value;
12124 
12125 	s32_min_val = src_reg.s32_min_value;
12126 	s32_max_val = src_reg.s32_max_value;
12127 	u32_min_val = src_reg.u32_min_value;
12128 	u32_max_val = src_reg.u32_max_value;
12129 
12130 	if (alu32) {
12131 		src_known = tnum_subreg_is_const(src_reg.var_off);
12132 		if ((src_known &&
12133 		     (s32_min_val != s32_max_val || u32_min_val != u32_max_val)) ||
12134 		    s32_min_val > s32_max_val || u32_min_val > u32_max_val) {
12135 			/* Taint dst register if offset had invalid bounds
12136 			 * derived from e.g. dead branches.
12137 			 */
12138 			__mark_reg_unknown(env, dst_reg);
12139 			return 0;
12140 		}
12141 	} else {
12142 		src_known = tnum_is_const(src_reg.var_off);
12143 		if ((src_known &&
12144 		     (smin_val != smax_val || umin_val != umax_val)) ||
12145 		    smin_val > smax_val || umin_val > umax_val) {
12146 			/* Taint dst register if offset had invalid bounds
12147 			 * derived from e.g. dead branches.
12148 			 */
12149 			__mark_reg_unknown(env, dst_reg);
12150 			return 0;
12151 		}
12152 	}
12153 
12154 	if (!src_known &&
12155 	    opcode != BPF_ADD && opcode != BPF_SUB && opcode != BPF_AND) {
12156 		__mark_reg_unknown(env, dst_reg);
12157 		return 0;
12158 	}
12159 
12160 	if (sanitize_needed(opcode)) {
12161 		ret = sanitize_val_alu(env, insn);
12162 		if (ret < 0)
12163 			return sanitize_err(env, insn, ret, NULL, NULL);
12164 	}
12165 
12166 	/* Calculate sign/unsigned bounds and tnum for alu32 and alu64 bit ops.
12167 	 * There are two classes of instructions: The first class we track both
12168 	 * alu32 and alu64 sign/unsigned bounds independently this provides the
12169 	 * greatest amount of precision when alu operations are mixed with jmp32
12170 	 * operations. These operations are BPF_ADD, BPF_SUB, BPF_MUL, BPF_ADD,
12171 	 * and BPF_OR. This is possible because these ops have fairly easy to
12172 	 * understand and calculate behavior in both 32-bit and 64-bit alu ops.
12173 	 * See alu32 verifier tests for examples. The second class of
12174 	 * operations, BPF_LSH, BPF_RSH, and BPF_ARSH, however are not so easy
12175 	 * with regards to tracking sign/unsigned bounds because the bits may
12176 	 * cross subreg boundaries in the alu64 case. When this happens we mark
12177 	 * the reg unbounded in the subreg bound space and use the resulting
12178 	 * tnum to calculate an approximation of the sign/unsigned bounds.
12179 	 */
12180 	switch (opcode) {
12181 	case BPF_ADD:
12182 		scalar32_min_max_add(dst_reg, &src_reg);
12183 		scalar_min_max_add(dst_reg, &src_reg);
12184 		dst_reg->var_off = tnum_add(dst_reg->var_off, src_reg.var_off);
12185 		break;
12186 	case BPF_SUB:
12187 		scalar32_min_max_sub(dst_reg, &src_reg);
12188 		scalar_min_max_sub(dst_reg, &src_reg);
12189 		dst_reg->var_off = tnum_sub(dst_reg->var_off, src_reg.var_off);
12190 		break;
12191 	case BPF_MUL:
12192 		dst_reg->var_off = tnum_mul(dst_reg->var_off, src_reg.var_off);
12193 		scalar32_min_max_mul(dst_reg, &src_reg);
12194 		scalar_min_max_mul(dst_reg, &src_reg);
12195 		break;
12196 	case BPF_AND:
12197 		dst_reg->var_off = tnum_and(dst_reg->var_off, src_reg.var_off);
12198 		scalar32_min_max_and(dst_reg, &src_reg);
12199 		scalar_min_max_and(dst_reg, &src_reg);
12200 		break;
12201 	case BPF_OR:
12202 		dst_reg->var_off = tnum_or(dst_reg->var_off, src_reg.var_off);
12203 		scalar32_min_max_or(dst_reg, &src_reg);
12204 		scalar_min_max_or(dst_reg, &src_reg);
12205 		break;
12206 	case BPF_XOR:
12207 		dst_reg->var_off = tnum_xor(dst_reg->var_off, src_reg.var_off);
12208 		scalar32_min_max_xor(dst_reg, &src_reg);
12209 		scalar_min_max_xor(dst_reg, &src_reg);
12210 		break;
12211 	case BPF_LSH:
12212 		if (umax_val >= insn_bitness) {
12213 			/* Shifts greater than 31 or 63 are undefined.
12214 			 * This includes shifts by a negative number.
12215 			 */
12216 			mark_reg_unknown(env, regs, insn->dst_reg);
12217 			break;
12218 		}
12219 		if (alu32)
12220 			scalar32_min_max_lsh(dst_reg, &src_reg);
12221 		else
12222 			scalar_min_max_lsh(dst_reg, &src_reg);
12223 		break;
12224 	case BPF_RSH:
12225 		if (umax_val >= insn_bitness) {
12226 			/* Shifts greater than 31 or 63 are undefined.
12227 			 * This includes shifts by a negative number.
12228 			 */
12229 			mark_reg_unknown(env, regs, insn->dst_reg);
12230 			break;
12231 		}
12232 		if (alu32)
12233 			scalar32_min_max_rsh(dst_reg, &src_reg);
12234 		else
12235 			scalar_min_max_rsh(dst_reg, &src_reg);
12236 		break;
12237 	case BPF_ARSH:
12238 		if (umax_val >= insn_bitness) {
12239 			/* Shifts greater than 31 or 63 are undefined.
12240 			 * This includes shifts by a negative number.
12241 			 */
12242 			mark_reg_unknown(env, regs, insn->dst_reg);
12243 			break;
12244 		}
12245 		if (alu32)
12246 			scalar32_min_max_arsh(dst_reg, &src_reg);
12247 		else
12248 			scalar_min_max_arsh(dst_reg, &src_reg);
12249 		break;
12250 	default:
12251 		mark_reg_unknown(env, regs, insn->dst_reg);
12252 		break;
12253 	}
12254 
12255 	/* ALU32 ops are zero extended into 64bit register */
12256 	if (alu32)
12257 		zext_32_to_64(dst_reg);
12258 	reg_bounds_sync(dst_reg);
12259 	return 0;
12260 }
12261 
12262 /* Handles ALU ops other than BPF_END, BPF_NEG and BPF_MOV: computes new min/max
12263  * and var_off.
12264  */
12265 static int adjust_reg_min_max_vals(struct bpf_verifier_env *env,
12266 				   struct bpf_insn *insn)
12267 {
12268 	struct bpf_verifier_state *vstate = env->cur_state;
12269 	struct bpf_func_state *state = vstate->frame[vstate->curframe];
12270 	struct bpf_reg_state *regs = state->regs, *dst_reg, *src_reg;
12271 	struct bpf_reg_state *ptr_reg = NULL, off_reg = {0};
12272 	u8 opcode = BPF_OP(insn->code);
12273 	int err;
12274 
12275 	dst_reg = &regs[insn->dst_reg];
12276 	src_reg = NULL;
12277 	if (dst_reg->type != SCALAR_VALUE)
12278 		ptr_reg = dst_reg;
12279 	else
12280 		/* Make sure ID is cleared otherwise dst_reg min/max could be
12281 		 * incorrectly propagated into other registers by find_equal_scalars()
12282 		 */
12283 		dst_reg->id = 0;
12284 	if (BPF_SRC(insn->code) == BPF_X) {
12285 		src_reg = &regs[insn->src_reg];
12286 		if (src_reg->type != SCALAR_VALUE) {
12287 			if (dst_reg->type != SCALAR_VALUE) {
12288 				/* Combining two pointers by any ALU op yields
12289 				 * an arbitrary scalar. Disallow all math except
12290 				 * pointer subtraction
12291 				 */
12292 				if (opcode == BPF_SUB && env->allow_ptr_leaks) {
12293 					mark_reg_unknown(env, regs, insn->dst_reg);
12294 					return 0;
12295 				}
12296 				verbose(env, "R%d pointer %s pointer prohibited\n",
12297 					insn->dst_reg,
12298 					bpf_alu_string[opcode >> 4]);
12299 				return -EACCES;
12300 			} else {
12301 				/* scalar += pointer
12302 				 * This is legal, but we have to reverse our
12303 				 * src/dest handling in computing the range
12304 				 */
12305 				err = mark_chain_precision(env, insn->dst_reg);
12306 				if (err)
12307 					return err;
12308 				return adjust_ptr_min_max_vals(env, insn,
12309 							       src_reg, dst_reg);
12310 			}
12311 		} else if (ptr_reg) {
12312 			/* pointer += scalar */
12313 			err = mark_chain_precision(env, insn->src_reg);
12314 			if (err)
12315 				return err;
12316 			return adjust_ptr_min_max_vals(env, insn,
12317 						       dst_reg, src_reg);
12318 		} else if (dst_reg->precise) {
12319 			/* if dst_reg is precise, src_reg should be precise as well */
12320 			err = mark_chain_precision(env, insn->src_reg);
12321 			if (err)
12322 				return err;
12323 		}
12324 	} else {
12325 		/* Pretend the src is a reg with a known value, since we only
12326 		 * need to be able to read from this state.
12327 		 */
12328 		off_reg.type = SCALAR_VALUE;
12329 		__mark_reg_known(&off_reg, insn->imm);
12330 		src_reg = &off_reg;
12331 		if (ptr_reg) /* pointer += K */
12332 			return adjust_ptr_min_max_vals(env, insn,
12333 						       ptr_reg, src_reg);
12334 	}
12335 
12336 	/* Got here implies adding two SCALAR_VALUEs */
12337 	if (WARN_ON_ONCE(ptr_reg)) {
12338 		print_verifier_state(env, state, true);
12339 		verbose(env, "verifier internal error: unexpected ptr_reg\n");
12340 		return -EINVAL;
12341 	}
12342 	if (WARN_ON(!src_reg)) {
12343 		print_verifier_state(env, state, true);
12344 		verbose(env, "verifier internal error: no src_reg\n");
12345 		return -EINVAL;
12346 	}
12347 	return adjust_scalar_min_max_vals(env, insn, dst_reg, *src_reg);
12348 }
12349 
12350 /* check validity of 32-bit and 64-bit arithmetic operations */
12351 static int check_alu_op(struct bpf_verifier_env *env, struct bpf_insn *insn)
12352 {
12353 	struct bpf_reg_state *regs = cur_regs(env);
12354 	u8 opcode = BPF_OP(insn->code);
12355 	int err;
12356 
12357 	if (opcode == BPF_END || opcode == BPF_NEG) {
12358 		if (opcode == BPF_NEG) {
12359 			if (BPF_SRC(insn->code) != BPF_K ||
12360 			    insn->src_reg != BPF_REG_0 ||
12361 			    insn->off != 0 || insn->imm != 0) {
12362 				verbose(env, "BPF_NEG uses reserved fields\n");
12363 				return -EINVAL;
12364 			}
12365 		} else {
12366 			if (insn->src_reg != BPF_REG_0 || insn->off != 0 ||
12367 			    (insn->imm != 16 && insn->imm != 32 && insn->imm != 64) ||
12368 			    BPF_CLASS(insn->code) == BPF_ALU64) {
12369 				verbose(env, "BPF_END uses reserved fields\n");
12370 				return -EINVAL;
12371 			}
12372 		}
12373 
12374 		/* check src operand */
12375 		err = check_reg_arg(env, insn->dst_reg, SRC_OP);
12376 		if (err)
12377 			return err;
12378 
12379 		if (is_pointer_value(env, insn->dst_reg)) {
12380 			verbose(env, "R%d pointer arithmetic prohibited\n",
12381 				insn->dst_reg);
12382 			return -EACCES;
12383 		}
12384 
12385 		/* check dest operand */
12386 		err = check_reg_arg(env, insn->dst_reg, DST_OP);
12387 		if (err)
12388 			return err;
12389 
12390 	} else if (opcode == BPF_MOV) {
12391 
12392 		if (BPF_SRC(insn->code) == BPF_X) {
12393 			if (insn->imm != 0 || insn->off != 0) {
12394 				verbose(env, "BPF_MOV uses reserved fields\n");
12395 				return -EINVAL;
12396 			}
12397 
12398 			/* check src operand */
12399 			err = check_reg_arg(env, insn->src_reg, SRC_OP);
12400 			if (err)
12401 				return err;
12402 		} else {
12403 			if (insn->src_reg != BPF_REG_0 || insn->off != 0) {
12404 				verbose(env, "BPF_MOV uses reserved fields\n");
12405 				return -EINVAL;
12406 			}
12407 		}
12408 
12409 		/* check dest operand, mark as required later */
12410 		err = check_reg_arg(env, insn->dst_reg, DST_OP_NO_MARK);
12411 		if (err)
12412 			return err;
12413 
12414 		if (BPF_SRC(insn->code) == BPF_X) {
12415 			struct bpf_reg_state *src_reg = regs + insn->src_reg;
12416 			struct bpf_reg_state *dst_reg = regs + insn->dst_reg;
12417 
12418 			if (BPF_CLASS(insn->code) == BPF_ALU64) {
12419 				/* case: R1 = R2
12420 				 * copy register state to dest reg
12421 				 */
12422 				if (src_reg->type == SCALAR_VALUE && !src_reg->id)
12423 					/* Assign src and dst registers the same ID
12424 					 * that will be used by find_equal_scalars()
12425 					 * to propagate min/max range.
12426 					 */
12427 					src_reg->id = ++env->id_gen;
12428 				copy_register_state(dst_reg, src_reg);
12429 				dst_reg->live |= REG_LIVE_WRITTEN;
12430 				dst_reg->subreg_def = DEF_NOT_SUBREG;
12431 			} else {
12432 				/* R1 = (u32) R2 */
12433 				if (is_pointer_value(env, insn->src_reg)) {
12434 					verbose(env,
12435 						"R%d partial copy of pointer\n",
12436 						insn->src_reg);
12437 					return -EACCES;
12438 				} else if (src_reg->type == SCALAR_VALUE) {
12439 					bool is_src_reg_u32 = src_reg->umax_value <= U32_MAX;
12440 
12441 					if (is_src_reg_u32 && !src_reg->id)
12442 						src_reg->id = ++env->id_gen;
12443 					copy_register_state(dst_reg, src_reg);
12444 					/* Make sure ID is cleared if src_reg is not in u32 range otherwise
12445 					 * dst_reg min/max could be incorrectly
12446 					 * propagated into src_reg by find_equal_scalars()
12447 					 */
12448 					if (!is_src_reg_u32)
12449 						dst_reg->id = 0;
12450 					dst_reg->live |= REG_LIVE_WRITTEN;
12451 					dst_reg->subreg_def = env->insn_idx + 1;
12452 				} else {
12453 					mark_reg_unknown(env, regs,
12454 							 insn->dst_reg);
12455 				}
12456 				zext_32_to_64(dst_reg);
12457 				reg_bounds_sync(dst_reg);
12458 			}
12459 		} else {
12460 			/* case: R = imm
12461 			 * remember the value we stored into this reg
12462 			 */
12463 			/* clear any state __mark_reg_known doesn't set */
12464 			mark_reg_unknown(env, regs, insn->dst_reg);
12465 			regs[insn->dst_reg].type = SCALAR_VALUE;
12466 			if (BPF_CLASS(insn->code) == BPF_ALU64) {
12467 				__mark_reg_known(regs + insn->dst_reg,
12468 						 insn->imm);
12469 			} else {
12470 				__mark_reg_known(regs + insn->dst_reg,
12471 						 (u32)insn->imm);
12472 			}
12473 		}
12474 
12475 	} else if (opcode > BPF_END) {
12476 		verbose(env, "invalid BPF_ALU opcode %x\n", opcode);
12477 		return -EINVAL;
12478 
12479 	} else {	/* all other ALU ops: and, sub, xor, add, ... */
12480 
12481 		if (BPF_SRC(insn->code) == BPF_X) {
12482 			if (insn->imm != 0 || insn->off != 0) {
12483 				verbose(env, "BPF_ALU uses reserved fields\n");
12484 				return -EINVAL;
12485 			}
12486 			/* check src1 operand */
12487 			err = check_reg_arg(env, insn->src_reg, SRC_OP);
12488 			if (err)
12489 				return err;
12490 		} else {
12491 			if (insn->src_reg != BPF_REG_0 || insn->off != 0) {
12492 				verbose(env, "BPF_ALU uses reserved fields\n");
12493 				return -EINVAL;
12494 			}
12495 		}
12496 
12497 		/* check src2 operand */
12498 		err = check_reg_arg(env, insn->dst_reg, SRC_OP);
12499 		if (err)
12500 			return err;
12501 
12502 		if ((opcode == BPF_MOD || opcode == BPF_DIV) &&
12503 		    BPF_SRC(insn->code) == BPF_K && insn->imm == 0) {
12504 			verbose(env, "div by zero\n");
12505 			return -EINVAL;
12506 		}
12507 
12508 		if ((opcode == BPF_LSH || opcode == BPF_RSH ||
12509 		     opcode == BPF_ARSH) && BPF_SRC(insn->code) == BPF_K) {
12510 			int size = BPF_CLASS(insn->code) == BPF_ALU64 ? 64 : 32;
12511 
12512 			if (insn->imm < 0 || insn->imm >= size) {
12513 				verbose(env, "invalid shift %d\n", insn->imm);
12514 				return -EINVAL;
12515 			}
12516 		}
12517 
12518 		/* check dest operand */
12519 		err = check_reg_arg(env, insn->dst_reg, DST_OP_NO_MARK);
12520 		if (err)
12521 			return err;
12522 
12523 		return adjust_reg_min_max_vals(env, insn);
12524 	}
12525 
12526 	return 0;
12527 }
12528 
12529 static void find_good_pkt_pointers(struct bpf_verifier_state *vstate,
12530 				   struct bpf_reg_state *dst_reg,
12531 				   enum bpf_reg_type type,
12532 				   bool range_right_open)
12533 {
12534 	struct bpf_func_state *state;
12535 	struct bpf_reg_state *reg;
12536 	int new_range;
12537 
12538 	if (dst_reg->off < 0 ||
12539 	    (dst_reg->off == 0 && range_right_open))
12540 		/* This doesn't give us any range */
12541 		return;
12542 
12543 	if (dst_reg->umax_value > MAX_PACKET_OFF ||
12544 	    dst_reg->umax_value + dst_reg->off > MAX_PACKET_OFF)
12545 		/* Risk of overflow.  For instance, ptr + (1<<63) may be less
12546 		 * than pkt_end, but that's because it's also less than pkt.
12547 		 */
12548 		return;
12549 
12550 	new_range = dst_reg->off;
12551 	if (range_right_open)
12552 		new_range++;
12553 
12554 	/* Examples for register markings:
12555 	 *
12556 	 * pkt_data in dst register:
12557 	 *
12558 	 *   r2 = r3;
12559 	 *   r2 += 8;
12560 	 *   if (r2 > pkt_end) goto <handle exception>
12561 	 *   <access okay>
12562 	 *
12563 	 *   r2 = r3;
12564 	 *   r2 += 8;
12565 	 *   if (r2 < pkt_end) goto <access okay>
12566 	 *   <handle exception>
12567 	 *
12568 	 *   Where:
12569 	 *     r2 == dst_reg, pkt_end == src_reg
12570 	 *     r2=pkt(id=n,off=8,r=0)
12571 	 *     r3=pkt(id=n,off=0,r=0)
12572 	 *
12573 	 * pkt_data in src register:
12574 	 *
12575 	 *   r2 = r3;
12576 	 *   r2 += 8;
12577 	 *   if (pkt_end >= r2) goto <access okay>
12578 	 *   <handle exception>
12579 	 *
12580 	 *   r2 = r3;
12581 	 *   r2 += 8;
12582 	 *   if (pkt_end <= r2) goto <handle exception>
12583 	 *   <access okay>
12584 	 *
12585 	 *   Where:
12586 	 *     pkt_end == dst_reg, r2 == src_reg
12587 	 *     r2=pkt(id=n,off=8,r=0)
12588 	 *     r3=pkt(id=n,off=0,r=0)
12589 	 *
12590 	 * Find register r3 and mark its range as r3=pkt(id=n,off=0,r=8)
12591 	 * or r3=pkt(id=n,off=0,r=8-1), so that range of bytes [r3, r3 + 8)
12592 	 * and [r3, r3 + 8-1) respectively is safe to access depending on
12593 	 * the check.
12594 	 */
12595 
12596 	/* If our ids match, then we must have the same max_value.  And we
12597 	 * don't care about the other reg's fixed offset, since if it's too big
12598 	 * the range won't allow anything.
12599 	 * dst_reg->off is known < MAX_PACKET_OFF, therefore it fits in a u16.
12600 	 */
12601 	bpf_for_each_reg_in_vstate(vstate, state, reg, ({
12602 		if (reg->type == type && reg->id == dst_reg->id)
12603 			/* keep the maximum range already checked */
12604 			reg->range = max(reg->range, new_range);
12605 	}));
12606 }
12607 
12608 static int is_branch32_taken(struct bpf_reg_state *reg, u32 val, u8 opcode)
12609 {
12610 	struct tnum subreg = tnum_subreg(reg->var_off);
12611 	s32 sval = (s32)val;
12612 
12613 	switch (opcode) {
12614 	case BPF_JEQ:
12615 		if (tnum_is_const(subreg))
12616 			return !!tnum_equals_const(subreg, val);
12617 		else if (val < reg->u32_min_value || val > reg->u32_max_value)
12618 			return 0;
12619 		break;
12620 	case BPF_JNE:
12621 		if (tnum_is_const(subreg))
12622 			return !tnum_equals_const(subreg, val);
12623 		else if (val < reg->u32_min_value || val > reg->u32_max_value)
12624 			return 1;
12625 		break;
12626 	case BPF_JSET:
12627 		if ((~subreg.mask & subreg.value) & val)
12628 			return 1;
12629 		if (!((subreg.mask | subreg.value) & val))
12630 			return 0;
12631 		break;
12632 	case BPF_JGT:
12633 		if (reg->u32_min_value > val)
12634 			return 1;
12635 		else if (reg->u32_max_value <= val)
12636 			return 0;
12637 		break;
12638 	case BPF_JSGT:
12639 		if (reg->s32_min_value > sval)
12640 			return 1;
12641 		else if (reg->s32_max_value <= sval)
12642 			return 0;
12643 		break;
12644 	case BPF_JLT:
12645 		if (reg->u32_max_value < val)
12646 			return 1;
12647 		else if (reg->u32_min_value >= val)
12648 			return 0;
12649 		break;
12650 	case BPF_JSLT:
12651 		if (reg->s32_max_value < sval)
12652 			return 1;
12653 		else if (reg->s32_min_value >= sval)
12654 			return 0;
12655 		break;
12656 	case BPF_JGE:
12657 		if (reg->u32_min_value >= val)
12658 			return 1;
12659 		else if (reg->u32_max_value < val)
12660 			return 0;
12661 		break;
12662 	case BPF_JSGE:
12663 		if (reg->s32_min_value >= sval)
12664 			return 1;
12665 		else if (reg->s32_max_value < sval)
12666 			return 0;
12667 		break;
12668 	case BPF_JLE:
12669 		if (reg->u32_max_value <= val)
12670 			return 1;
12671 		else if (reg->u32_min_value > val)
12672 			return 0;
12673 		break;
12674 	case BPF_JSLE:
12675 		if (reg->s32_max_value <= sval)
12676 			return 1;
12677 		else if (reg->s32_min_value > sval)
12678 			return 0;
12679 		break;
12680 	}
12681 
12682 	return -1;
12683 }
12684 
12685 
12686 static int is_branch64_taken(struct bpf_reg_state *reg, u64 val, u8 opcode)
12687 {
12688 	s64 sval = (s64)val;
12689 
12690 	switch (opcode) {
12691 	case BPF_JEQ:
12692 		if (tnum_is_const(reg->var_off))
12693 			return !!tnum_equals_const(reg->var_off, val);
12694 		else if (val < reg->umin_value || val > reg->umax_value)
12695 			return 0;
12696 		break;
12697 	case BPF_JNE:
12698 		if (tnum_is_const(reg->var_off))
12699 			return !tnum_equals_const(reg->var_off, val);
12700 		else if (val < reg->umin_value || val > reg->umax_value)
12701 			return 1;
12702 		break;
12703 	case BPF_JSET:
12704 		if ((~reg->var_off.mask & reg->var_off.value) & val)
12705 			return 1;
12706 		if (!((reg->var_off.mask | reg->var_off.value) & val))
12707 			return 0;
12708 		break;
12709 	case BPF_JGT:
12710 		if (reg->umin_value > val)
12711 			return 1;
12712 		else if (reg->umax_value <= val)
12713 			return 0;
12714 		break;
12715 	case BPF_JSGT:
12716 		if (reg->smin_value > sval)
12717 			return 1;
12718 		else if (reg->smax_value <= sval)
12719 			return 0;
12720 		break;
12721 	case BPF_JLT:
12722 		if (reg->umax_value < val)
12723 			return 1;
12724 		else if (reg->umin_value >= val)
12725 			return 0;
12726 		break;
12727 	case BPF_JSLT:
12728 		if (reg->smax_value < sval)
12729 			return 1;
12730 		else if (reg->smin_value >= sval)
12731 			return 0;
12732 		break;
12733 	case BPF_JGE:
12734 		if (reg->umin_value >= val)
12735 			return 1;
12736 		else if (reg->umax_value < val)
12737 			return 0;
12738 		break;
12739 	case BPF_JSGE:
12740 		if (reg->smin_value >= sval)
12741 			return 1;
12742 		else if (reg->smax_value < sval)
12743 			return 0;
12744 		break;
12745 	case BPF_JLE:
12746 		if (reg->umax_value <= val)
12747 			return 1;
12748 		else if (reg->umin_value > val)
12749 			return 0;
12750 		break;
12751 	case BPF_JSLE:
12752 		if (reg->smax_value <= sval)
12753 			return 1;
12754 		else if (reg->smin_value > sval)
12755 			return 0;
12756 		break;
12757 	}
12758 
12759 	return -1;
12760 }
12761 
12762 /* compute branch direction of the expression "if (reg opcode val) goto target;"
12763  * and return:
12764  *  1 - branch will be taken and "goto target" will be executed
12765  *  0 - branch will not be taken and fall-through to next insn
12766  * -1 - unknown. Example: "if (reg < 5)" is unknown when register value
12767  *      range [0,10]
12768  */
12769 static int is_branch_taken(struct bpf_reg_state *reg, u64 val, u8 opcode,
12770 			   bool is_jmp32)
12771 {
12772 	if (__is_pointer_value(false, reg)) {
12773 		if (!reg_type_not_null(reg->type))
12774 			return -1;
12775 
12776 		/* If pointer is valid tests against zero will fail so we can
12777 		 * use this to direct branch taken.
12778 		 */
12779 		if (val != 0)
12780 			return -1;
12781 
12782 		switch (opcode) {
12783 		case BPF_JEQ:
12784 			return 0;
12785 		case BPF_JNE:
12786 			return 1;
12787 		default:
12788 			return -1;
12789 		}
12790 	}
12791 
12792 	if (is_jmp32)
12793 		return is_branch32_taken(reg, val, opcode);
12794 	return is_branch64_taken(reg, val, opcode);
12795 }
12796 
12797 static int flip_opcode(u32 opcode)
12798 {
12799 	/* How can we transform "a <op> b" into "b <op> a"? */
12800 	static const u8 opcode_flip[16] = {
12801 		/* these stay the same */
12802 		[BPF_JEQ  >> 4] = BPF_JEQ,
12803 		[BPF_JNE  >> 4] = BPF_JNE,
12804 		[BPF_JSET >> 4] = BPF_JSET,
12805 		/* these swap "lesser" and "greater" (L and G in the opcodes) */
12806 		[BPF_JGE  >> 4] = BPF_JLE,
12807 		[BPF_JGT  >> 4] = BPF_JLT,
12808 		[BPF_JLE  >> 4] = BPF_JGE,
12809 		[BPF_JLT  >> 4] = BPF_JGT,
12810 		[BPF_JSGE >> 4] = BPF_JSLE,
12811 		[BPF_JSGT >> 4] = BPF_JSLT,
12812 		[BPF_JSLE >> 4] = BPF_JSGE,
12813 		[BPF_JSLT >> 4] = BPF_JSGT
12814 	};
12815 	return opcode_flip[opcode >> 4];
12816 }
12817 
12818 static int is_pkt_ptr_branch_taken(struct bpf_reg_state *dst_reg,
12819 				   struct bpf_reg_state *src_reg,
12820 				   u8 opcode)
12821 {
12822 	struct bpf_reg_state *pkt;
12823 
12824 	if (src_reg->type == PTR_TO_PACKET_END) {
12825 		pkt = dst_reg;
12826 	} else if (dst_reg->type == PTR_TO_PACKET_END) {
12827 		pkt = src_reg;
12828 		opcode = flip_opcode(opcode);
12829 	} else {
12830 		return -1;
12831 	}
12832 
12833 	if (pkt->range >= 0)
12834 		return -1;
12835 
12836 	switch (opcode) {
12837 	case BPF_JLE:
12838 		/* pkt <= pkt_end */
12839 		fallthrough;
12840 	case BPF_JGT:
12841 		/* pkt > pkt_end */
12842 		if (pkt->range == BEYOND_PKT_END)
12843 			/* pkt has at last one extra byte beyond pkt_end */
12844 			return opcode == BPF_JGT;
12845 		break;
12846 	case BPF_JLT:
12847 		/* pkt < pkt_end */
12848 		fallthrough;
12849 	case BPF_JGE:
12850 		/* pkt >= pkt_end */
12851 		if (pkt->range == BEYOND_PKT_END || pkt->range == AT_PKT_END)
12852 			return opcode == BPF_JGE;
12853 		break;
12854 	}
12855 	return -1;
12856 }
12857 
12858 /* Adjusts the register min/max values in the case that the dst_reg is the
12859  * variable register that we are working on, and src_reg is a constant or we're
12860  * simply doing a BPF_K check.
12861  * In JEQ/JNE cases we also adjust the var_off values.
12862  */
12863 static void reg_set_min_max(struct bpf_reg_state *true_reg,
12864 			    struct bpf_reg_state *false_reg,
12865 			    u64 val, u32 val32,
12866 			    u8 opcode, bool is_jmp32)
12867 {
12868 	struct tnum false_32off = tnum_subreg(false_reg->var_off);
12869 	struct tnum false_64off = false_reg->var_off;
12870 	struct tnum true_32off = tnum_subreg(true_reg->var_off);
12871 	struct tnum true_64off = true_reg->var_off;
12872 	s64 sval = (s64)val;
12873 	s32 sval32 = (s32)val32;
12874 
12875 	/* If the dst_reg is a pointer, we can't learn anything about its
12876 	 * variable offset from the compare (unless src_reg were a pointer into
12877 	 * the same object, but we don't bother with that.
12878 	 * Since false_reg and true_reg have the same type by construction, we
12879 	 * only need to check one of them for pointerness.
12880 	 */
12881 	if (__is_pointer_value(false, false_reg))
12882 		return;
12883 
12884 	switch (opcode) {
12885 	/* JEQ/JNE comparison doesn't change the register equivalence.
12886 	 *
12887 	 * r1 = r2;
12888 	 * if (r1 == 42) goto label;
12889 	 * ...
12890 	 * label: // here both r1 and r2 are known to be 42.
12891 	 *
12892 	 * Hence when marking register as known preserve it's ID.
12893 	 */
12894 	case BPF_JEQ:
12895 		if (is_jmp32) {
12896 			__mark_reg32_known(true_reg, val32);
12897 			true_32off = tnum_subreg(true_reg->var_off);
12898 		} else {
12899 			___mark_reg_known(true_reg, val);
12900 			true_64off = true_reg->var_off;
12901 		}
12902 		break;
12903 	case BPF_JNE:
12904 		if (is_jmp32) {
12905 			__mark_reg32_known(false_reg, val32);
12906 			false_32off = tnum_subreg(false_reg->var_off);
12907 		} else {
12908 			___mark_reg_known(false_reg, val);
12909 			false_64off = false_reg->var_off;
12910 		}
12911 		break;
12912 	case BPF_JSET:
12913 		if (is_jmp32) {
12914 			false_32off = tnum_and(false_32off, tnum_const(~val32));
12915 			if (is_power_of_2(val32))
12916 				true_32off = tnum_or(true_32off,
12917 						     tnum_const(val32));
12918 		} else {
12919 			false_64off = tnum_and(false_64off, tnum_const(~val));
12920 			if (is_power_of_2(val))
12921 				true_64off = tnum_or(true_64off,
12922 						     tnum_const(val));
12923 		}
12924 		break;
12925 	case BPF_JGE:
12926 	case BPF_JGT:
12927 	{
12928 		if (is_jmp32) {
12929 			u32 false_umax = opcode == BPF_JGT ? val32  : val32 - 1;
12930 			u32 true_umin = opcode == BPF_JGT ? val32 + 1 : val32;
12931 
12932 			false_reg->u32_max_value = min(false_reg->u32_max_value,
12933 						       false_umax);
12934 			true_reg->u32_min_value = max(true_reg->u32_min_value,
12935 						      true_umin);
12936 		} else {
12937 			u64 false_umax = opcode == BPF_JGT ? val    : val - 1;
12938 			u64 true_umin = opcode == BPF_JGT ? val + 1 : val;
12939 
12940 			false_reg->umax_value = min(false_reg->umax_value, false_umax);
12941 			true_reg->umin_value = max(true_reg->umin_value, true_umin);
12942 		}
12943 		break;
12944 	}
12945 	case BPF_JSGE:
12946 	case BPF_JSGT:
12947 	{
12948 		if (is_jmp32) {
12949 			s32 false_smax = opcode == BPF_JSGT ? sval32    : sval32 - 1;
12950 			s32 true_smin = opcode == BPF_JSGT ? sval32 + 1 : sval32;
12951 
12952 			false_reg->s32_max_value = min(false_reg->s32_max_value, false_smax);
12953 			true_reg->s32_min_value = max(true_reg->s32_min_value, true_smin);
12954 		} else {
12955 			s64 false_smax = opcode == BPF_JSGT ? sval    : sval - 1;
12956 			s64 true_smin = opcode == BPF_JSGT ? sval + 1 : sval;
12957 
12958 			false_reg->smax_value = min(false_reg->smax_value, false_smax);
12959 			true_reg->smin_value = max(true_reg->smin_value, true_smin);
12960 		}
12961 		break;
12962 	}
12963 	case BPF_JLE:
12964 	case BPF_JLT:
12965 	{
12966 		if (is_jmp32) {
12967 			u32 false_umin = opcode == BPF_JLT ? val32  : val32 + 1;
12968 			u32 true_umax = opcode == BPF_JLT ? val32 - 1 : val32;
12969 
12970 			false_reg->u32_min_value = max(false_reg->u32_min_value,
12971 						       false_umin);
12972 			true_reg->u32_max_value = min(true_reg->u32_max_value,
12973 						      true_umax);
12974 		} else {
12975 			u64 false_umin = opcode == BPF_JLT ? val    : val + 1;
12976 			u64 true_umax = opcode == BPF_JLT ? val - 1 : val;
12977 
12978 			false_reg->umin_value = max(false_reg->umin_value, false_umin);
12979 			true_reg->umax_value = min(true_reg->umax_value, true_umax);
12980 		}
12981 		break;
12982 	}
12983 	case BPF_JSLE:
12984 	case BPF_JSLT:
12985 	{
12986 		if (is_jmp32) {
12987 			s32 false_smin = opcode == BPF_JSLT ? sval32    : sval32 + 1;
12988 			s32 true_smax = opcode == BPF_JSLT ? sval32 - 1 : sval32;
12989 
12990 			false_reg->s32_min_value = max(false_reg->s32_min_value, false_smin);
12991 			true_reg->s32_max_value = min(true_reg->s32_max_value, true_smax);
12992 		} else {
12993 			s64 false_smin = opcode == BPF_JSLT ? sval    : sval + 1;
12994 			s64 true_smax = opcode == BPF_JSLT ? sval - 1 : sval;
12995 
12996 			false_reg->smin_value = max(false_reg->smin_value, false_smin);
12997 			true_reg->smax_value = min(true_reg->smax_value, true_smax);
12998 		}
12999 		break;
13000 	}
13001 	default:
13002 		return;
13003 	}
13004 
13005 	if (is_jmp32) {
13006 		false_reg->var_off = tnum_or(tnum_clear_subreg(false_64off),
13007 					     tnum_subreg(false_32off));
13008 		true_reg->var_off = tnum_or(tnum_clear_subreg(true_64off),
13009 					    tnum_subreg(true_32off));
13010 		__reg_combine_32_into_64(false_reg);
13011 		__reg_combine_32_into_64(true_reg);
13012 	} else {
13013 		false_reg->var_off = false_64off;
13014 		true_reg->var_off = true_64off;
13015 		__reg_combine_64_into_32(false_reg);
13016 		__reg_combine_64_into_32(true_reg);
13017 	}
13018 }
13019 
13020 /* Same as above, but for the case that dst_reg holds a constant and src_reg is
13021  * the variable reg.
13022  */
13023 static void reg_set_min_max_inv(struct bpf_reg_state *true_reg,
13024 				struct bpf_reg_state *false_reg,
13025 				u64 val, u32 val32,
13026 				u8 opcode, bool is_jmp32)
13027 {
13028 	opcode = flip_opcode(opcode);
13029 	/* This uses zero as "not present in table"; luckily the zero opcode,
13030 	 * BPF_JA, can't get here.
13031 	 */
13032 	if (opcode)
13033 		reg_set_min_max(true_reg, false_reg, val, val32, opcode, is_jmp32);
13034 }
13035 
13036 /* Regs are known to be equal, so intersect their min/max/var_off */
13037 static void __reg_combine_min_max(struct bpf_reg_state *src_reg,
13038 				  struct bpf_reg_state *dst_reg)
13039 {
13040 	src_reg->umin_value = dst_reg->umin_value = max(src_reg->umin_value,
13041 							dst_reg->umin_value);
13042 	src_reg->umax_value = dst_reg->umax_value = min(src_reg->umax_value,
13043 							dst_reg->umax_value);
13044 	src_reg->smin_value = dst_reg->smin_value = max(src_reg->smin_value,
13045 							dst_reg->smin_value);
13046 	src_reg->smax_value = dst_reg->smax_value = min(src_reg->smax_value,
13047 							dst_reg->smax_value);
13048 	src_reg->var_off = dst_reg->var_off = tnum_intersect(src_reg->var_off,
13049 							     dst_reg->var_off);
13050 	reg_bounds_sync(src_reg);
13051 	reg_bounds_sync(dst_reg);
13052 }
13053 
13054 static void reg_combine_min_max(struct bpf_reg_state *true_src,
13055 				struct bpf_reg_state *true_dst,
13056 				struct bpf_reg_state *false_src,
13057 				struct bpf_reg_state *false_dst,
13058 				u8 opcode)
13059 {
13060 	switch (opcode) {
13061 	case BPF_JEQ:
13062 		__reg_combine_min_max(true_src, true_dst);
13063 		break;
13064 	case BPF_JNE:
13065 		__reg_combine_min_max(false_src, false_dst);
13066 		break;
13067 	}
13068 }
13069 
13070 static void mark_ptr_or_null_reg(struct bpf_func_state *state,
13071 				 struct bpf_reg_state *reg, u32 id,
13072 				 bool is_null)
13073 {
13074 	if (type_may_be_null(reg->type) && reg->id == id &&
13075 	    (is_rcu_reg(reg) || !WARN_ON_ONCE(!reg->id))) {
13076 		/* Old offset (both fixed and variable parts) should have been
13077 		 * known-zero, because we don't allow pointer arithmetic on
13078 		 * pointers that might be NULL. If we see this happening, don't
13079 		 * convert the register.
13080 		 *
13081 		 * But in some cases, some helpers that return local kptrs
13082 		 * advance offset for the returned pointer. In those cases, it
13083 		 * is fine to expect to see reg->off.
13084 		 */
13085 		if (WARN_ON_ONCE(reg->smin_value || reg->smax_value || !tnum_equals_const(reg->var_off, 0)))
13086 			return;
13087 		if (!(type_is_ptr_alloc_obj(reg->type) || type_is_non_owning_ref(reg->type)) &&
13088 		    WARN_ON_ONCE(reg->off))
13089 			return;
13090 
13091 		if (is_null) {
13092 			reg->type = SCALAR_VALUE;
13093 			/* We don't need id and ref_obj_id from this point
13094 			 * onwards anymore, thus we should better reset it,
13095 			 * so that state pruning has chances to take effect.
13096 			 */
13097 			reg->id = 0;
13098 			reg->ref_obj_id = 0;
13099 
13100 			return;
13101 		}
13102 
13103 		mark_ptr_not_null_reg(reg);
13104 
13105 		if (!reg_may_point_to_spin_lock(reg)) {
13106 			/* For not-NULL ptr, reg->ref_obj_id will be reset
13107 			 * in release_reference().
13108 			 *
13109 			 * reg->id is still used by spin_lock ptr. Other
13110 			 * than spin_lock ptr type, reg->id can be reset.
13111 			 */
13112 			reg->id = 0;
13113 		}
13114 	}
13115 }
13116 
13117 /* The logic is similar to find_good_pkt_pointers(), both could eventually
13118  * be folded together at some point.
13119  */
13120 static void mark_ptr_or_null_regs(struct bpf_verifier_state *vstate, u32 regno,
13121 				  bool is_null)
13122 {
13123 	struct bpf_func_state *state = vstate->frame[vstate->curframe];
13124 	struct bpf_reg_state *regs = state->regs, *reg;
13125 	u32 ref_obj_id = regs[regno].ref_obj_id;
13126 	u32 id = regs[regno].id;
13127 
13128 	if (ref_obj_id && ref_obj_id == id && is_null)
13129 		/* regs[regno] is in the " == NULL" branch.
13130 		 * No one could have freed the reference state before
13131 		 * doing the NULL check.
13132 		 */
13133 		WARN_ON_ONCE(release_reference_state(state, id));
13134 
13135 	bpf_for_each_reg_in_vstate(vstate, state, reg, ({
13136 		mark_ptr_or_null_reg(state, reg, id, is_null);
13137 	}));
13138 }
13139 
13140 static bool try_match_pkt_pointers(const struct bpf_insn *insn,
13141 				   struct bpf_reg_state *dst_reg,
13142 				   struct bpf_reg_state *src_reg,
13143 				   struct bpf_verifier_state *this_branch,
13144 				   struct bpf_verifier_state *other_branch)
13145 {
13146 	if (BPF_SRC(insn->code) != BPF_X)
13147 		return false;
13148 
13149 	/* Pointers are always 64-bit. */
13150 	if (BPF_CLASS(insn->code) == BPF_JMP32)
13151 		return false;
13152 
13153 	switch (BPF_OP(insn->code)) {
13154 	case BPF_JGT:
13155 		if ((dst_reg->type == PTR_TO_PACKET &&
13156 		     src_reg->type == PTR_TO_PACKET_END) ||
13157 		    (dst_reg->type == PTR_TO_PACKET_META &&
13158 		     reg_is_init_pkt_pointer(src_reg, PTR_TO_PACKET))) {
13159 			/* pkt_data' > pkt_end, pkt_meta' > pkt_data */
13160 			find_good_pkt_pointers(this_branch, dst_reg,
13161 					       dst_reg->type, false);
13162 			mark_pkt_end(other_branch, insn->dst_reg, true);
13163 		} else if ((dst_reg->type == PTR_TO_PACKET_END &&
13164 			    src_reg->type == PTR_TO_PACKET) ||
13165 			   (reg_is_init_pkt_pointer(dst_reg, PTR_TO_PACKET) &&
13166 			    src_reg->type == PTR_TO_PACKET_META)) {
13167 			/* pkt_end > pkt_data', pkt_data > pkt_meta' */
13168 			find_good_pkt_pointers(other_branch, src_reg,
13169 					       src_reg->type, true);
13170 			mark_pkt_end(this_branch, insn->src_reg, false);
13171 		} else {
13172 			return false;
13173 		}
13174 		break;
13175 	case BPF_JLT:
13176 		if ((dst_reg->type == PTR_TO_PACKET &&
13177 		     src_reg->type == PTR_TO_PACKET_END) ||
13178 		    (dst_reg->type == PTR_TO_PACKET_META &&
13179 		     reg_is_init_pkt_pointer(src_reg, PTR_TO_PACKET))) {
13180 			/* pkt_data' < pkt_end, pkt_meta' < pkt_data */
13181 			find_good_pkt_pointers(other_branch, dst_reg,
13182 					       dst_reg->type, true);
13183 			mark_pkt_end(this_branch, insn->dst_reg, false);
13184 		} else if ((dst_reg->type == PTR_TO_PACKET_END &&
13185 			    src_reg->type == PTR_TO_PACKET) ||
13186 			   (reg_is_init_pkt_pointer(dst_reg, PTR_TO_PACKET) &&
13187 			    src_reg->type == PTR_TO_PACKET_META)) {
13188 			/* pkt_end < pkt_data', pkt_data > pkt_meta' */
13189 			find_good_pkt_pointers(this_branch, src_reg,
13190 					       src_reg->type, false);
13191 			mark_pkt_end(other_branch, insn->src_reg, true);
13192 		} else {
13193 			return false;
13194 		}
13195 		break;
13196 	case BPF_JGE:
13197 		if ((dst_reg->type == PTR_TO_PACKET &&
13198 		     src_reg->type == PTR_TO_PACKET_END) ||
13199 		    (dst_reg->type == PTR_TO_PACKET_META &&
13200 		     reg_is_init_pkt_pointer(src_reg, PTR_TO_PACKET))) {
13201 			/* pkt_data' >= pkt_end, pkt_meta' >= pkt_data */
13202 			find_good_pkt_pointers(this_branch, dst_reg,
13203 					       dst_reg->type, true);
13204 			mark_pkt_end(other_branch, insn->dst_reg, false);
13205 		} else if ((dst_reg->type == PTR_TO_PACKET_END &&
13206 			    src_reg->type == PTR_TO_PACKET) ||
13207 			   (reg_is_init_pkt_pointer(dst_reg, PTR_TO_PACKET) &&
13208 			    src_reg->type == PTR_TO_PACKET_META)) {
13209 			/* pkt_end >= pkt_data', pkt_data >= pkt_meta' */
13210 			find_good_pkt_pointers(other_branch, src_reg,
13211 					       src_reg->type, false);
13212 			mark_pkt_end(this_branch, insn->src_reg, true);
13213 		} else {
13214 			return false;
13215 		}
13216 		break;
13217 	case BPF_JLE:
13218 		if ((dst_reg->type == PTR_TO_PACKET &&
13219 		     src_reg->type == PTR_TO_PACKET_END) ||
13220 		    (dst_reg->type == PTR_TO_PACKET_META &&
13221 		     reg_is_init_pkt_pointer(src_reg, PTR_TO_PACKET))) {
13222 			/* pkt_data' <= pkt_end, pkt_meta' <= pkt_data */
13223 			find_good_pkt_pointers(other_branch, dst_reg,
13224 					       dst_reg->type, false);
13225 			mark_pkt_end(this_branch, insn->dst_reg, true);
13226 		} else if ((dst_reg->type == PTR_TO_PACKET_END &&
13227 			    src_reg->type == PTR_TO_PACKET) ||
13228 			   (reg_is_init_pkt_pointer(dst_reg, PTR_TO_PACKET) &&
13229 			    src_reg->type == PTR_TO_PACKET_META)) {
13230 			/* pkt_end <= pkt_data', pkt_data <= pkt_meta' */
13231 			find_good_pkt_pointers(this_branch, src_reg,
13232 					       src_reg->type, true);
13233 			mark_pkt_end(other_branch, insn->src_reg, false);
13234 		} else {
13235 			return false;
13236 		}
13237 		break;
13238 	default:
13239 		return false;
13240 	}
13241 
13242 	return true;
13243 }
13244 
13245 static void find_equal_scalars(struct bpf_verifier_state *vstate,
13246 			       struct bpf_reg_state *known_reg)
13247 {
13248 	struct bpf_func_state *state;
13249 	struct bpf_reg_state *reg;
13250 
13251 	bpf_for_each_reg_in_vstate(vstate, state, reg, ({
13252 		if (reg->type == SCALAR_VALUE && reg->id == known_reg->id)
13253 			copy_register_state(reg, known_reg);
13254 	}));
13255 }
13256 
13257 static int check_cond_jmp_op(struct bpf_verifier_env *env,
13258 			     struct bpf_insn *insn, int *insn_idx)
13259 {
13260 	struct bpf_verifier_state *this_branch = env->cur_state;
13261 	struct bpf_verifier_state *other_branch;
13262 	struct bpf_reg_state *regs = this_branch->frame[this_branch->curframe]->regs;
13263 	struct bpf_reg_state *dst_reg, *other_branch_regs, *src_reg = NULL;
13264 	struct bpf_reg_state *eq_branch_regs;
13265 	u8 opcode = BPF_OP(insn->code);
13266 	bool is_jmp32;
13267 	int pred = -1;
13268 	int err;
13269 
13270 	/* Only conditional jumps are expected to reach here. */
13271 	if (opcode == BPF_JA || opcode > BPF_JSLE) {
13272 		verbose(env, "invalid BPF_JMP/JMP32 opcode %x\n", opcode);
13273 		return -EINVAL;
13274 	}
13275 
13276 	if (BPF_SRC(insn->code) == BPF_X) {
13277 		if (insn->imm != 0) {
13278 			verbose(env, "BPF_JMP/JMP32 uses reserved fields\n");
13279 			return -EINVAL;
13280 		}
13281 
13282 		/* check src1 operand */
13283 		err = check_reg_arg(env, insn->src_reg, SRC_OP);
13284 		if (err)
13285 			return err;
13286 
13287 		if (is_pointer_value(env, insn->src_reg)) {
13288 			verbose(env, "R%d pointer comparison prohibited\n",
13289 				insn->src_reg);
13290 			return -EACCES;
13291 		}
13292 		src_reg = &regs[insn->src_reg];
13293 	} else {
13294 		if (insn->src_reg != BPF_REG_0) {
13295 			verbose(env, "BPF_JMP/JMP32 uses reserved fields\n");
13296 			return -EINVAL;
13297 		}
13298 	}
13299 
13300 	/* check src2 operand */
13301 	err = check_reg_arg(env, insn->dst_reg, SRC_OP);
13302 	if (err)
13303 		return err;
13304 
13305 	dst_reg = &regs[insn->dst_reg];
13306 	is_jmp32 = BPF_CLASS(insn->code) == BPF_JMP32;
13307 
13308 	if (BPF_SRC(insn->code) == BPF_K) {
13309 		pred = is_branch_taken(dst_reg, insn->imm, opcode, is_jmp32);
13310 	} else if (src_reg->type == SCALAR_VALUE &&
13311 		   is_jmp32 && tnum_is_const(tnum_subreg(src_reg->var_off))) {
13312 		pred = is_branch_taken(dst_reg,
13313 				       tnum_subreg(src_reg->var_off).value,
13314 				       opcode,
13315 				       is_jmp32);
13316 	} else if (src_reg->type == SCALAR_VALUE &&
13317 		   !is_jmp32 && tnum_is_const(src_reg->var_off)) {
13318 		pred = is_branch_taken(dst_reg,
13319 				       src_reg->var_off.value,
13320 				       opcode,
13321 				       is_jmp32);
13322 	} else if (dst_reg->type == SCALAR_VALUE &&
13323 		   is_jmp32 && tnum_is_const(tnum_subreg(dst_reg->var_off))) {
13324 		pred = is_branch_taken(src_reg,
13325 				       tnum_subreg(dst_reg->var_off).value,
13326 				       flip_opcode(opcode),
13327 				       is_jmp32);
13328 	} else if (dst_reg->type == SCALAR_VALUE &&
13329 		   !is_jmp32 && tnum_is_const(dst_reg->var_off)) {
13330 		pred = is_branch_taken(src_reg,
13331 				       dst_reg->var_off.value,
13332 				       flip_opcode(opcode),
13333 				       is_jmp32);
13334 	} else if (reg_is_pkt_pointer_any(dst_reg) &&
13335 		   reg_is_pkt_pointer_any(src_reg) &&
13336 		   !is_jmp32) {
13337 		pred = is_pkt_ptr_branch_taken(dst_reg, src_reg, opcode);
13338 	}
13339 
13340 	if (pred >= 0) {
13341 		/* If we get here with a dst_reg pointer type it is because
13342 		 * above is_branch_taken() special cased the 0 comparison.
13343 		 */
13344 		if (!__is_pointer_value(false, dst_reg))
13345 			err = mark_chain_precision(env, insn->dst_reg);
13346 		if (BPF_SRC(insn->code) == BPF_X && !err &&
13347 		    !__is_pointer_value(false, src_reg))
13348 			err = mark_chain_precision(env, insn->src_reg);
13349 		if (err)
13350 			return err;
13351 	}
13352 
13353 	if (pred == 1) {
13354 		/* Only follow the goto, ignore fall-through. If needed, push
13355 		 * the fall-through branch for simulation under speculative
13356 		 * execution.
13357 		 */
13358 		if (!env->bypass_spec_v1 &&
13359 		    !sanitize_speculative_path(env, insn, *insn_idx + 1,
13360 					       *insn_idx))
13361 			return -EFAULT;
13362 		*insn_idx += insn->off;
13363 		return 0;
13364 	} else if (pred == 0) {
13365 		/* Only follow the fall-through branch, since that's where the
13366 		 * program will go. If needed, push the goto branch for
13367 		 * simulation under speculative execution.
13368 		 */
13369 		if (!env->bypass_spec_v1 &&
13370 		    !sanitize_speculative_path(env, insn,
13371 					       *insn_idx + insn->off + 1,
13372 					       *insn_idx))
13373 			return -EFAULT;
13374 		return 0;
13375 	}
13376 
13377 	other_branch = push_stack(env, *insn_idx + insn->off + 1, *insn_idx,
13378 				  false);
13379 	if (!other_branch)
13380 		return -EFAULT;
13381 	other_branch_regs = other_branch->frame[other_branch->curframe]->regs;
13382 
13383 	/* detect if we are comparing against a constant value so we can adjust
13384 	 * our min/max values for our dst register.
13385 	 * this is only legit if both are scalars (or pointers to the same
13386 	 * object, I suppose, see the PTR_MAYBE_NULL related if block below),
13387 	 * because otherwise the different base pointers mean the offsets aren't
13388 	 * comparable.
13389 	 */
13390 	if (BPF_SRC(insn->code) == BPF_X) {
13391 		struct bpf_reg_state *src_reg = &regs[insn->src_reg];
13392 
13393 		if (dst_reg->type == SCALAR_VALUE &&
13394 		    src_reg->type == SCALAR_VALUE) {
13395 			if (tnum_is_const(src_reg->var_off) ||
13396 			    (is_jmp32 &&
13397 			     tnum_is_const(tnum_subreg(src_reg->var_off))))
13398 				reg_set_min_max(&other_branch_regs[insn->dst_reg],
13399 						dst_reg,
13400 						src_reg->var_off.value,
13401 						tnum_subreg(src_reg->var_off).value,
13402 						opcode, is_jmp32);
13403 			else if (tnum_is_const(dst_reg->var_off) ||
13404 				 (is_jmp32 &&
13405 				  tnum_is_const(tnum_subreg(dst_reg->var_off))))
13406 				reg_set_min_max_inv(&other_branch_regs[insn->src_reg],
13407 						    src_reg,
13408 						    dst_reg->var_off.value,
13409 						    tnum_subreg(dst_reg->var_off).value,
13410 						    opcode, is_jmp32);
13411 			else if (!is_jmp32 &&
13412 				 (opcode == BPF_JEQ || opcode == BPF_JNE))
13413 				/* Comparing for equality, we can combine knowledge */
13414 				reg_combine_min_max(&other_branch_regs[insn->src_reg],
13415 						    &other_branch_regs[insn->dst_reg],
13416 						    src_reg, dst_reg, opcode);
13417 			if (src_reg->id &&
13418 			    !WARN_ON_ONCE(src_reg->id != other_branch_regs[insn->src_reg].id)) {
13419 				find_equal_scalars(this_branch, src_reg);
13420 				find_equal_scalars(other_branch, &other_branch_regs[insn->src_reg]);
13421 			}
13422 
13423 		}
13424 	} else if (dst_reg->type == SCALAR_VALUE) {
13425 		reg_set_min_max(&other_branch_regs[insn->dst_reg],
13426 					dst_reg, insn->imm, (u32)insn->imm,
13427 					opcode, is_jmp32);
13428 	}
13429 
13430 	if (dst_reg->type == SCALAR_VALUE && dst_reg->id &&
13431 	    !WARN_ON_ONCE(dst_reg->id != other_branch_regs[insn->dst_reg].id)) {
13432 		find_equal_scalars(this_branch, dst_reg);
13433 		find_equal_scalars(other_branch, &other_branch_regs[insn->dst_reg]);
13434 	}
13435 
13436 	/* if one pointer register is compared to another pointer
13437 	 * register check if PTR_MAYBE_NULL could be lifted.
13438 	 * E.g. register A - maybe null
13439 	 *      register B - not null
13440 	 * for JNE A, B, ... - A is not null in the false branch;
13441 	 * for JEQ A, B, ... - A is not null in the true branch.
13442 	 *
13443 	 * Since PTR_TO_BTF_ID points to a kernel struct that does
13444 	 * not need to be null checked by the BPF program, i.e.,
13445 	 * could be null even without PTR_MAYBE_NULL marking, so
13446 	 * only propagate nullness when neither reg is that type.
13447 	 */
13448 	if (!is_jmp32 && BPF_SRC(insn->code) == BPF_X &&
13449 	    __is_pointer_value(false, src_reg) && __is_pointer_value(false, dst_reg) &&
13450 	    type_may_be_null(src_reg->type) != type_may_be_null(dst_reg->type) &&
13451 	    base_type(src_reg->type) != PTR_TO_BTF_ID &&
13452 	    base_type(dst_reg->type) != PTR_TO_BTF_ID) {
13453 		eq_branch_regs = NULL;
13454 		switch (opcode) {
13455 		case BPF_JEQ:
13456 			eq_branch_regs = other_branch_regs;
13457 			break;
13458 		case BPF_JNE:
13459 			eq_branch_regs = regs;
13460 			break;
13461 		default:
13462 			/* do nothing */
13463 			break;
13464 		}
13465 		if (eq_branch_regs) {
13466 			if (type_may_be_null(src_reg->type))
13467 				mark_ptr_not_null_reg(&eq_branch_regs[insn->src_reg]);
13468 			else
13469 				mark_ptr_not_null_reg(&eq_branch_regs[insn->dst_reg]);
13470 		}
13471 	}
13472 
13473 	/* detect if R == 0 where R is returned from bpf_map_lookup_elem().
13474 	 * NOTE: these optimizations below are related with pointer comparison
13475 	 *       which will never be JMP32.
13476 	 */
13477 	if (!is_jmp32 && BPF_SRC(insn->code) == BPF_K &&
13478 	    insn->imm == 0 && (opcode == BPF_JEQ || opcode == BPF_JNE) &&
13479 	    type_may_be_null(dst_reg->type)) {
13480 		/* Mark all identical registers in each branch as either
13481 		 * safe or unknown depending R == 0 or R != 0 conditional.
13482 		 */
13483 		mark_ptr_or_null_regs(this_branch, insn->dst_reg,
13484 				      opcode == BPF_JNE);
13485 		mark_ptr_or_null_regs(other_branch, insn->dst_reg,
13486 				      opcode == BPF_JEQ);
13487 	} else if (!try_match_pkt_pointers(insn, dst_reg, &regs[insn->src_reg],
13488 					   this_branch, other_branch) &&
13489 		   is_pointer_value(env, insn->dst_reg)) {
13490 		verbose(env, "R%d pointer comparison prohibited\n",
13491 			insn->dst_reg);
13492 		return -EACCES;
13493 	}
13494 	if (env->log.level & BPF_LOG_LEVEL)
13495 		print_insn_state(env, this_branch->frame[this_branch->curframe]);
13496 	return 0;
13497 }
13498 
13499 /* verify BPF_LD_IMM64 instruction */
13500 static int check_ld_imm(struct bpf_verifier_env *env, struct bpf_insn *insn)
13501 {
13502 	struct bpf_insn_aux_data *aux = cur_aux(env);
13503 	struct bpf_reg_state *regs = cur_regs(env);
13504 	struct bpf_reg_state *dst_reg;
13505 	struct bpf_map *map;
13506 	int err;
13507 
13508 	if (BPF_SIZE(insn->code) != BPF_DW) {
13509 		verbose(env, "invalid BPF_LD_IMM insn\n");
13510 		return -EINVAL;
13511 	}
13512 	if (insn->off != 0) {
13513 		verbose(env, "BPF_LD_IMM64 uses reserved fields\n");
13514 		return -EINVAL;
13515 	}
13516 
13517 	err = check_reg_arg(env, insn->dst_reg, DST_OP);
13518 	if (err)
13519 		return err;
13520 
13521 	dst_reg = &regs[insn->dst_reg];
13522 	if (insn->src_reg == 0) {
13523 		u64 imm = ((u64)(insn + 1)->imm << 32) | (u32)insn->imm;
13524 
13525 		dst_reg->type = SCALAR_VALUE;
13526 		__mark_reg_known(&regs[insn->dst_reg], imm);
13527 		return 0;
13528 	}
13529 
13530 	/* All special src_reg cases are listed below. From this point onwards
13531 	 * we either succeed and assign a corresponding dst_reg->type after
13532 	 * zeroing the offset, or fail and reject the program.
13533 	 */
13534 	mark_reg_known_zero(env, regs, insn->dst_reg);
13535 
13536 	if (insn->src_reg == BPF_PSEUDO_BTF_ID) {
13537 		dst_reg->type = aux->btf_var.reg_type;
13538 		switch (base_type(dst_reg->type)) {
13539 		case PTR_TO_MEM:
13540 			dst_reg->mem_size = aux->btf_var.mem_size;
13541 			break;
13542 		case PTR_TO_BTF_ID:
13543 			dst_reg->btf = aux->btf_var.btf;
13544 			dst_reg->btf_id = aux->btf_var.btf_id;
13545 			break;
13546 		default:
13547 			verbose(env, "bpf verifier is misconfigured\n");
13548 			return -EFAULT;
13549 		}
13550 		return 0;
13551 	}
13552 
13553 	if (insn->src_reg == BPF_PSEUDO_FUNC) {
13554 		struct bpf_prog_aux *aux = env->prog->aux;
13555 		u32 subprogno = find_subprog(env,
13556 					     env->insn_idx + insn->imm + 1);
13557 
13558 		if (!aux->func_info) {
13559 			verbose(env, "missing btf func_info\n");
13560 			return -EINVAL;
13561 		}
13562 		if (aux->func_info_aux[subprogno].linkage != BTF_FUNC_STATIC) {
13563 			verbose(env, "callback function not static\n");
13564 			return -EINVAL;
13565 		}
13566 
13567 		dst_reg->type = PTR_TO_FUNC;
13568 		dst_reg->subprogno = subprogno;
13569 		return 0;
13570 	}
13571 
13572 	map = env->used_maps[aux->map_index];
13573 	dst_reg->map_ptr = map;
13574 
13575 	if (insn->src_reg == BPF_PSEUDO_MAP_VALUE ||
13576 	    insn->src_reg == BPF_PSEUDO_MAP_IDX_VALUE) {
13577 		dst_reg->type = PTR_TO_MAP_VALUE;
13578 		dst_reg->off = aux->map_off;
13579 		WARN_ON_ONCE(map->max_entries != 1);
13580 		/* We want reg->id to be same (0) as map_value is not distinct */
13581 	} else if (insn->src_reg == BPF_PSEUDO_MAP_FD ||
13582 		   insn->src_reg == BPF_PSEUDO_MAP_IDX) {
13583 		dst_reg->type = CONST_PTR_TO_MAP;
13584 	} else {
13585 		verbose(env, "bpf verifier is misconfigured\n");
13586 		return -EINVAL;
13587 	}
13588 
13589 	return 0;
13590 }
13591 
13592 static bool may_access_skb(enum bpf_prog_type type)
13593 {
13594 	switch (type) {
13595 	case BPF_PROG_TYPE_SOCKET_FILTER:
13596 	case BPF_PROG_TYPE_SCHED_CLS:
13597 	case BPF_PROG_TYPE_SCHED_ACT:
13598 		return true;
13599 	default:
13600 		return false;
13601 	}
13602 }
13603 
13604 /* verify safety of LD_ABS|LD_IND instructions:
13605  * - they can only appear in the programs where ctx == skb
13606  * - since they are wrappers of function calls, they scratch R1-R5 registers,
13607  *   preserve R6-R9, and store return value into R0
13608  *
13609  * Implicit input:
13610  *   ctx == skb == R6 == CTX
13611  *
13612  * Explicit input:
13613  *   SRC == any register
13614  *   IMM == 32-bit immediate
13615  *
13616  * Output:
13617  *   R0 - 8/16/32-bit skb data converted to cpu endianness
13618  */
13619 static int check_ld_abs(struct bpf_verifier_env *env, struct bpf_insn *insn)
13620 {
13621 	struct bpf_reg_state *regs = cur_regs(env);
13622 	static const int ctx_reg = BPF_REG_6;
13623 	u8 mode = BPF_MODE(insn->code);
13624 	int i, err;
13625 
13626 	if (!may_access_skb(resolve_prog_type(env->prog))) {
13627 		verbose(env, "BPF_LD_[ABS|IND] instructions not allowed for this program type\n");
13628 		return -EINVAL;
13629 	}
13630 
13631 	if (!env->ops->gen_ld_abs) {
13632 		verbose(env, "bpf verifier is misconfigured\n");
13633 		return -EINVAL;
13634 	}
13635 
13636 	if (insn->dst_reg != BPF_REG_0 || insn->off != 0 ||
13637 	    BPF_SIZE(insn->code) == BPF_DW ||
13638 	    (mode == BPF_ABS && insn->src_reg != BPF_REG_0)) {
13639 		verbose(env, "BPF_LD_[ABS|IND] uses reserved fields\n");
13640 		return -EINVAL;
13641 	}
13642 
13643 	/* check whether implicit source operand (register R6) is readable */
13644 	err = check_reg_arg(env, ctx_reg, SRC_OP);
13645 	if (err)
13646 		return err;
13647 
13648 	/* Disallow usage of BPF_LD_[ABS|IND] with reference tracking, as
13649 	 * gen_ld_abs() may terminate the program at runtime, leading to
13650 	 * reference leak.
13651 	 */
13652 	err = check_reference_leak(env);
13653 	if (err) {
13654 		verbose(env, "BPF_LD_[ABS|IND] cannot be mixed with socket references\n");
13655 		return err;
13656 	}
13657 
13658 	if (env->cur_state->active_lock.ptr) {
13659 		verbose(env, "BPF_LD_[ABS|IND] cannot be used inside bpf_spin_lock-ed region\n");
13660 		return -EINVAL;
13661 	}
13662 
13663 	if (env->cur_state->active_rcu_lock) {
13664 		verbose(env, "BPF_LD_[ABS|IND] cannot be used inside bpf_rcu_read_lock-ed region\n");
13665 		return -EINVAL;
13666 	}
13667 
13668 	if (regs[ctx_reg].type != PTR_TO_CTX) {
13669 		verbose(env,
13670 			"at the time of BPF_LD_ABS|IND R6 != pointer to skb\n");
13671 		return -EINVAL;
13672 	}
13673 
13674 	if (mode == BPF_IND) {
13675 		/* check explicit source operand */
13676 		err = check_reg_arg(env, insn->src_reg, SRC_OP);
13677 		if (err)
13678 			return err;
13679 	}
13680 
13681 	err = check_ptr_off_reg(env, &regs[ctx_reg], ctx_reg);
13682 	if (err < 0)
13683 		return err;
13684 
13685 	/* reset caller saved regs to unreadable */
13686 	for (i = 0; i < CALLER_SAVED_REGS; i++) {
13687 		mark_reg_not_init(env, regs, caller_saved[i]);
13688 		check_reg_arg(env, caller_saved[i], DST_OP_NO_MARK);
13689 	}
13690 
13691 	/* mark destination R0 register as readable, since it contains
13692 	 * the value fetched from the packet.
13693 	 * Already marked as written above.
13694 	 */
13695 	mark_reg_unknown(env, regs, BPF_REG_0);
13696 	/* ld_abs load up to 32-bit skb data. */
13697 	regs[BPF_REG_0].subreg_def = env->insn_idx + 1;
13698 	return 0;
13699 }
13700 
13701 static int check_return_code(struct bpf_verifier_env *env)
13702 {
13703 	struct tnum enforce_attach_type_range = tnum_unknown;
13704 	const struct bpf_prog *prog = env->prog;
13705 	struct bpf_reg_state *reg;
13706 	struct tnum range = tnum_range(0, 1);
13707 	enum bpf_prog_type prog_type = resolve_prog_type(env->prog);
13708 	int err;
13709 	struct bpf_func_state *frame = env->cur_state->frame[0];
13710 	const bool is_subprog = frame->subprogno;
13711 
13712 	/* LSM and struct_ops func-ptr's return type could be "void" */
13713 	if (!is_subprog) {
13714 		switch (prog_type) {
13715 		case BPF_PROG_TYPE_LSM:
13716 			if (prog->expected_attach_type == BPF_LSM_CGROUP)
13717 				/* See below, can be 0 or 0-1 depending on hook. */
13718 				break;
13719 			fallthrough;
13720 		case BPF_PROG_TYPE_STRUCT_OPS:
13721 			if (!prog->aux->attach_func_proto->type)
13722 				return 0;
13723 			break;
13724 		default:
13725 			break;
13726 		}
13727 	}
13728 
13729 	/* eBPF calling convention is such that R0 is used
13730 	 * to return the value from eBPF program.
13731 	 * Make sure that it's readable at this time
13732 	 * of bpf_exit, which means that program wrote
13733 	 * something into it earlier
13734 	 */
13735 	err = check_reg_arg(env, BPF_REG_0, SRC_OP);
13736 	if (err)
13737 		return err;
13738 
13739 	if (is_pointer_value(env, BPF_REG_0)) {
13740 		verbose(env, "R0 leaks addr as return value\n");
13741 		return -EACCES;
13742 	}
13743 
13744 	reg = cur_regs(env) + BPF_REG_0;
13745 
13746 	if (frame->in_async_callback_fn) {
13747 		/* enforce return zero from async callbacks like timer */
13748 		if (reg->type != SCALAR_VALUE) {
13749 			verbose(env, "In async callback the register R0 is not a known value (%s)\n",
13750 				reg_type_str(env, reg->type));
13751 			return -EINVAL;
13752 		}
13753 
13754 		if (!tnum_in(tnum_const(0), reg->var_off)) {
13755 			verbose_invalid_scalar(env, reg, &range, "async callback", "R0");
13756 			return -EINVAL;
13757 		}
13758 		return 0;
13759 	}
13760 
13761 	if (is_subprog) {
13762 		if (reg->type != SCALAR_VALUE) {
13763 			verbose(env, "At subprogram exit the register R0 is not a scalar value (%s)\n",
13764 				reg_type_str(env, reg->type));
13765 			return -EINVAL;
13766 		}
13767 		return 0;
13768 	}
13769 
13770 	switch (prog_type) {
13771 	case BPF_PROG_TYPE_CGROUP_SOCK_ADDR:
13772 		if (env->prog->expected_attach_type == BPF_CGROUP_UDP4_RECVMSG ||
13773 		    env->prog->expected_attach_type == BPF_CGROUP_UDP6_RECVMSG ||
13774 		    env->prog->expected_attach_type == BPF_CGROUP_INET4_GETPEERNAME ||
13775 		    env->prog->expected_attach_type == BPF_CGROUP_INET6_GETPEERNAME ||
13776 		    env->prog->expected_attach_type == BPF_CGROUP_INET4_GETSOCKNAME ||
13777 		    env->prog->expected_attach_type == BPF_CGROUP_INET6_GETSOCKNAME)
13778 			range = tnum_range(1, 1);
13779 		if (env->prog->expected_attach_type == BPF_CGROUP_INET4_BIND ||
13780 		    env->prog->expected_attach_type == BPF_CGROUP_INET6_BIND)
13781 			range = tnum_range(0, 3);
13782 		break;
13783 	case BPF_PROG_TYPE_CGROUP_SKB:
13784 		if (env->prog->expected_attach_type == BPF_CGROUP_INET_EGRESS) {
13785 			range = tnum_range(0, 3);
13786 			enforce_attach_type_range = tnum_range(2, 3);
13787 		}
13788 		break;
13789 	case BPF_PROG_TYPE_CGROUP_SOCK:
13790 	case BPF_PROG_TYPE_SOCK_OPS:
13791 	case BPF_PROG_TYPE_CGROUP_DEVICE:
13792 	case BPF_PROG_TYPE_CGROUP_SYSCTL:
13793 	case BPF_PROG_TYPE_CGROUP_SOCKOPT:
13794 		break;
13795 	case BPF_PROG_TYPE_RAW_TRACEPOINT:
13796 		if (!env->prog->aux->attach_btf_id)
13797 			return 0;
13798 		range = tnum_const(0);
13799 		break;
13800 	case BPF_PROG_TYPE_TRACING:
13801 		switch (env->prog->expected_attach_type) {
13802 		case BPF_TRACE_FENTRY:
13803 		case BPF_TRACE_FEXIT:
13804 			range = tnum_const(0);
13805 			break;
13806 		case BPF_TRACE_RAW_TP:
13807 		case BPF_MODIFY_RETURN:
13808 			return 0;
13809 		case BPF_TRACE_ITER:
13810 			break;
13811 		default:
13812 			return -ENOTSUPP;
13813 		}
13814 		break;
13815 	case BPF_PROG_TYPE_SK_LOOKUP:
13816 		range = tnum_range(SK_DROP, SK_PASS);
13817 		break;
13818 
13819 	case BPF_PROG_TYPE_LSM:
13820 		if (env->prog->expected_attach_type != BPF_LSM_CGROUP) {
13821 			/* Regular BPF_PROG_TYPE_LSM programs can return
13822 			 * any value.
13823 			 */
13824 			return 0;
13825 		}
13826 		if (!env->prog->aux->attach_func_proto->type) {
13827 			/* Make sure programs that attach to void
13828 			 * hooks don't try to modify return value.
13829 			 */
13830 			range = tnum_range(1, 1);
13831 		}
13832 		break;
13833 
13834 	case BPF_PROG_TYPE_NETFILTER:
13835 		range = tnum_range(NF_DROP, NF_ACCEPT);
13836 		break;
13837 	case BPF_PROG_TYPE_EXT:
13838 		/* freplace program can return anything as its return value
13839 		 * depends on the to-be-replaced kernel func or bpf program.
13840 		 */
13841 	default:
13842 		return 0;
13843 	}
13844 
13845 	if (reg->type != SCALAR_VALUE) {
13846 		verbose(env, "At program exit the register R0 is not a known value (%s)\n",
13847 			reg_type_str(env, reg->type));
13848 		return -EINVAL;
13849 	}
13850 
13851 	if (!tnum_in(range, reg->var_off)) {
13852 		verbose_invalid_scalar(env, reg, &range, "program exit", "R0");
13853 		if (prog->expected_attach_type == BPF_LSM_CGROUP &&
13854 		    prog_type == BPF_PROG_TYPE_LSM &&
13855 		    !prog->aux->attach_func_proto->type)
13856 			verbose(env, "Note, BPF_LSM_CGROUP that attach to void LSM hooks can't modify return value!\n");
13857 		return -EINVAL;
13858 	}
13859 
13860 	if (!tnum_is_unknown(enforce_attach_type_range) &&
13861 	    tnum_in(enforce_attach_type_range, reg->var_off))
13862 		env->prog->enforce_expected_attach_type = 1;
13863 	return 0;
13864 }
13865 
13866 /* non-recursive DFS pseudo code
13867  * 1  procedure DFS-iterative(G,v):
13868  * 2      label v as discovered
13869  * 3      let S be a stack
13870  * 4      S.push(v)
13871  * 5      while S is not empty
13872  * 6            t <- S.peek()
13873  * 7            if t is what we're looking for:
13874  * 8                return t
13875  * 9            for all edges e in G.adjacentEdges(t) do
13876  * 10               if edge e is already labelled
13877  * 11                   continue with the next edge
13878  * 12               w <- G.adjacentVertex(t,e)
13879  * 13               if vertex w is not discovered and not explored
13880  * 14                   label e as tree-edge
13881  * 15                   label w as discovered
13882  * 16                   S.push(w)
13883  * 17                   continue at 5
13884  * 18               else if vertex w is discovered
13885  * 19                   label e as back-edge
13886  * 20               else
13887  * 21                   // vertex w is explored
13888  * 22                   label e as forward- or cross-edge
13889  * 23           label t as explored
13890  * 24           S.pop()
13891  *
13892  * convention:
13893  * 0x10 - discovered
13894  * 0x11 - discovered and fall-through edge labelled
13895  * 0x12 - discovered and fall-through and branch edges labelled
13896  * 0x20 - explored
13897  */
13898 
13899 enum {
13900 	DISCOVERED = 0x10,
13901 	EXPLORED = 0x20,
13902 	FALLTHROUGH = 1,
13903 	BRANCH = 2,
13904 };
13905 
13906 static u32 state_htab_size(struct bpf_verifier_env *env)
13907 {
13908 	return env->prog->len;
13909 }
13910 
13911 static struct bpf_verifier_state_list **explored_state(
13912 					struct bpf_verifier_env *env,
13913 					int idx)
13914 {
13915 	struct bpf_verifier_state *cur = env->cur_state;
13916 	struct bpf_func_state *state = cur->frame[cur->curframe];
13917 
13918 	return &env->explored_states[(idx ^ state->callsite) % state_htab_size(env)];
13919 }
13920 
13921 static void mark_prune_point(struct bpf_verifier_env *env, int idx)
13922 {
13923 	env->insn_aux_data[idx].prune_point = true;
13924 }
13925 
13926 static bool is_prune_point(struct bpf_verifier_env *env, int insn_idx)
13927 {
13928 	return env->insn_aux_data[insn_idx].prune_point;
13929 }
13930 
13931 static void mark_force_checkpoint(struct bpf_verifier_env *env, int idx)
13932 {
13933 	env->insn_aux_data[idx].force_checkpoint = true;
13934 }
13935 
13936 static bool is_force_checkpoint(struct bpf_verifier_env *env, int insn_idx)
13937 {
13938 	return env->insn_aux_data[insn_idx].force_checkpoint;
13939 }
13940 
13941 
13942 enum {
13943 	DONE_EXPLORING = 0,
13944 	KEEP_EXPLORING = 1,
13945 };
13946 
13947 /* t, w, e - match pseudo-code above:
13948  * t - index of current instruction
13949  * w - next instruction
13950  * e - edge
13951  */
13952 static int push_insn(int t, int w, int e, struct bpf_verifier_env *env,
13953 		     bool loop_ok)
13954 {
13955 	int *insn_stack = env->cfg.insn_stack;
13956 	int *insn_state = env->cfg.insn_state;
13957 
13958 	if (e == FALLTHROUGH && insn_state[t] >= (DISCOVERED | FALLTHROUGH))
13959 		return DONE_EXPLORING;
13960 
13961 	if (e == BRANCH && insn_state[t] >= (DISCOVERED | BRANCH))
13962 		return DONE_EXPLORING;
13963 
13964 	if (w < 0 || w >= env->prog->len) {
13965 		verbose_linfo(env, t, "%d: ", t);
13966 		verbose(env, "jump out of range from insn %d to %d\n", t, w);
13967 		return -EINVAL;
13968 	}
13969 
13970 	if (e == BRANCH) {
13971 		/* mark branch target for state pruning */
13972 		mark_prune_point(env, w);
13973 		mark_jmp_point(env, w);
13974 	}
13975 
13976 	if (insn_state[w] == 0) {
13977 		/* tree-edge */
13978 		insn_state[t] = DISCOVERED | e;
13979 		insn_state[w] = DISCOVERED;
13980 		if (env->cfg.cur_stack >= env->prog->len)
13981 			return -E2BIG;
13982 		insn_stack[env->cfg.cur_stack++] = w;
13983 		return KEEP_EXPLORING;
13984 	} else if ((insn_state[w] & 0xF0) == DISCOVERED) {
13985 		if (loop_ok && env->bpf_capable)
13986 			return DONE_EXPLORING;
13987 		verbose_linfo(env, t, "%d: ", t);
13988 		verbose_linfo(env, w, "%d: ", w);
13989 		verbose(env, "back-edge from insn %d to %d\n", t, w);
13990 		return -EINVAL;
13991 	} else if (insn_state[w] == EXPLORED) {
13992 		/* forward- or cross-edge */
13993 		insn_state[t] = DISCOVERED | e;
13994 	} else {
13995 		verbose(env, "insn state internal bug\n");
13996 		return -EFAULT;
13997 	}
13998 	return DONE_EXPLORING;
13999 }
14000 
14001 static int visit_func_call_insn(int t, struct bpf_insn *insns,
14002 				struct bpf_verifier_env *env,
14003 				bool visit_callee)
14004 {
14005 	int ret;
14006 
14007 	ret = push_insn(t, t + 1, FALLTHROUGH, env, false);
14008 	if (ret)
14009 		return ret;
14010 
14011 	mark_prune_point(env, t + 1);
14012 	/* when we exit from subprog, we need to record non-linear history */
14013 	mark_jmp_point(env, t + 1);
14014 
14015 	if (visit_callee) {
14016 		mark_prune_point(env, t);
14017 		ret = push_insn(t, t + insns[t].imm + 1, BRANCH, env,
14018 				/* It's ok to allow recursion from CFG point of
14019 				 * view. __check_func_call() will do the actual
14020 				 * check.
14021 				 */
14022 				bpf_pseudo_func(insns + t));
14023 	}
14024 	return ret;
14025 }
14026 
14027 /* Visits the instruction at index t and returns one of the following:
14028  *  < 0 - an error occurred
14029  *  DONE_EXPLORING - the instruction was fully explored
14030  *  KEEP_EXPLORING - there is still work to be done before it is fully explored
14031  */
14032 static int visit_insn(int t, struct bpf_verifier_env *env)
14033 {
14034 	struct bpf_insn *insns = env->prog->insnsi, *insn = &insns[t];
14035 	int ret;
14036 
14037 	if (bpf_pseudo_func(insn))
14038 		return visit_func_call_insn(t, insns, env, true);
14039 
14040 	/* All non-branch instructions have a single fall-through edge. */
14041 	if (BPF_CLASS(insn->code) != BPF_JMP &&
14042 	    BPF_CLASS(insn->code) != BPF_JMP32)
14043 		return push_insn(t, t + 1, FALLTHROUGH, env, false);
14044 
14045 	switch (BPF_OP(insn->code)) {
14046 	case BPF_EXIT:
14047 		return DONE_EXPLORING;
14048 
14049 	case BPF_CALL:
14050 		if (insn->src_reg == 0 && insn->imm == BPF_FUNC_timer_set_callback)
14051 			/* Mark this call insn as a prune point to trigger
14052 			 * is_state_visited() check before call itself is
14053 			 * processed by __check_func_call(). Otherwise new
14054 			 * async state will be pushed for further exploration.
14055 			 */
14056 			mark_prune_point(env, t);
14057 		if (insn->src_reg == BPF_PSEUDO_KFUNC_CALL) {
14058 			struct bpf_kfunc_call_arg_meta meta;
14059 
14060 			ret = fetch_kfunc_meta(env, insn, &meta, NULL);
14061 			if (ret == 0 && is_iter_next_kfunc(&meta)) {
14062 				mark_prune_point(env, t);
14063 				/* Checking and saving state checkpoints at iter_next() call
14064 				 * is crucial for fast convergence of open-coded iterator loop
14065 				 * logic, so we need to force it. If we don't do that,
14066 				 * is_state_visited() might skip saving a checkpoint, causing
14067 				 * unnecessarily long sequence of not checkpointed
14068 				 * instructions and jumps, leading to exhaustion of jump
14069 				 * history buffer, and potentially other undesired outcomes.
14070 				 * It is expected that with correct open-coded iterators
14071 				 * convergence will happen quickly, so we don't run a risk of
14072 				 * exhausting memory.
14073 				 */
14074 				mark_force_checkpoint(env, t);
14075 			}
14076 		}
14077 		return visit_func_call_insn(t, insns, env, insn->src_reg == BPF_PSEUDO_CALL);
14078 
14079 	case BPF_JA:
14080 		if (BPF_SRC(insn->code) != BPF_K)
14081 			return -EINVAL;
14082 
14083 		/* unconditional jump with single edge */
14084 		ret = push_insn(t, t + insn->off + 1, FALLTHROUGH, env,
14085 				true);
14086 		if (ret)
14087 			return ret;
14088 
14089 		mark_prune_point(env, t + insn->off + 1);
14090 		mark_jmp_point(env, t + insn->off + 1);
14091 
14092 		return ret;
14093 
14094 	default:
14095 		/* conditional jump with two edges */
14096 		mark_prune_point(env, t);
14097 
14098 		ret = push_insn(t, t + 1, FALLTHROUGH, env, true);
14099 		if (ret)
14100 			return ret;
14101 
14102 		return push_insn(t, t + insn->off + 1, BRANCH, env, true);
14103 	}
14104 }
14105 
14106 /* non-recursive depth-first-search to detect loops in BPF program
14107  * loop == back-edge in directed graph
14108  */
14109 static int check_cfg(struct bpf_verifier_env *env)
14110 {
14111 	int insn_cnt = env->prog->len;
14112 	int *insn_stack, *insn_state;
14113 	int ret = 0;
14114 	int i;
14115 
14116 	insn_state = env->cfg.insn_state = kvcalloc(insn_cnt, sizeof(int), GFP_KERNEL);
14117 	if (!insn_state)
14118 		return -ENOMEM;
14119 
14120 	insn_stack = env->cfg.insn_stack = kvcalloc(insn_cnt, sizeof(int), GFP_KERNEL);
14121 	if (!insn_stack) {
14122 		kvfree(insn_state);
14123 		return -ENOMEM;
14124 	}
14125 
14126 	insn_state[0] = DISCOVERED; /* mark 1st insn as discovered */
14127 	insn_stack[0] = 0; /* 0 is the first instruction */
14128 	env->cfg.cur_stack = 1;
14129 
14130 	while (env->cfg.cur_stack > 0) {
14131 		int t = insn_stack[env->cfg.cur_stack - 1];
14132 
14133 		ret = visit_insn(t, env);
14134 		switch (ret) {
14135 		case DONE_EXPLORING:
14136 			insn_state[t] = EXPLORED;
14137 			env->cfg.cur_stack--;
14138 			break;
14139 		case KEEP_EXPLORING:
14140 			break;
14141 		default:
14142 			if (ret > 0) {
14143 				verbose(env, "visit_insn internal bug\n");
14144 				ret = -EFAULT;
14145 			}
14146 			goto err_free;
14147 		}
14148 	}
14149 
14150 	if (env->cfg.cur_stack < 0) {
14151 		verbose(env, "pop stack internal bug\n");
14152 		ret = -EFAULT;
14153 		goto err_free;
14154 	}
14155 
14156 	for (i = 0; i < insn_cnt; i++) {
14157 		if (insn_state[i] != EXPLORED) {
14158 			verbose(env, "unreachable insn %d\n", i);
14159 			ret = -EINVAL;
14160 			goto err_free;
14161 		}
14162 	}
14163 	ret = 0; /* cfg looks good */
14164 
14165 err_free:
14166 	kvfree(insn_state);
14167 	kvfree(insn_stack);
14168 	env->cfg.insn_state = env->cfg.insn_stack = NULL;
14169 	return ret;
14170 }
14171 
14172 static int check_abnormal_return(struct bpf_verifier_env *env)
14173 {
14174 	int i;
14175 
14176 	for (i = 1; i < env->subprog_cnt; i++) {
14177 		if (env->subprog_info[i].has_ld_abs) {
14178 			verbose(env, "LD_ABS is not allowed in subprogs without BTF\n");
14179 			return -EINVAL;
14180 		}
14181 		if (env->subprog_info[i].has_tail_call) {
14182 			verbose(env, "tail_call is not allowed in subprogs without BTF\n");
14183 			return -EINVAL;
14184 		}
14185 	}
14186 	return 0;
14187 }
14188 
14189 /* The minimum supported BTF func info size */
14190 #define MIN_BPF_FUNCINFO_SIZE	8
14191 #define MAX_FUNCINFO_REC_SIZE	252
14192 
14193 static int check_btf_func(struct bpf_verifier_env *env,
14194 			  const union bpf_attr *attr,
14195 			  bpfptr_t uattr)
14196 {
14197 	const struct btf_type *type, *func_proto, *ret_type;
14198 	u32 i, nfuncs, urec_size, min_size;
14199 	u32 krec_size = sizeof(struct bpf_func_info);
14200 	struct bpf_func_info *krecord;
14201 	struct bpf_func_info_aux *info_aux = NULL;
14202 	struct bpf_prog *prog;
14203 	const struct btf *btf;
14204 	bpfptr_t urecord;
14205 	u32 prev_offset = 0;
14206 	bool scalar_return;
14207 	int ret = -ENOMEM;
14208 
14209 	nfuncs = attr->func_info_cnt;
14210 	if (!nfuncs) {
14211 		if (check_abnormal_return(env))
14212 			return -EINVAL;
14213 		return 0;
14214 	}
14215 
14216 	if (nfuncs != env->subprog_cnt) {
14217 		verbose(env, "number of funcs in func_info doesn't match number of subprogs\n");
14218 		return -EINVAL;
14219 	}
14220 
14221 	urec_size = attr->func_info_rec_size;
14222 	if (urec_size < MIN_BPF_FUNCINFO_SIZE ||
14223 	    urec_size > MAX_FUNCINFO_REC_SIZE ||
14224 	    urec_size % sizeof(u32)) {
14225 		verbose(env, "invalid func info rec size %u\n", urec_size);
14226 		return -EINVAL;
14227 	}
14228 
14229 	prog = env->prog;
14230 	btf = prog->aux->btf;
14231 
14232 	urecord = make_bpfptr(attr->func_info, uattr.is_kernel);
14233 	min_size = min_t(u32, krec_size, urec_size);
14234 
14235 	krecord = kvcalloc(nfuncs, krec_size, GFP_KERNEL | __GFP_NOWARN);
14236 	if (!krecord)
14237 		return -ENOMEM;
14238 	info_aux = kcalloc(nfuncs, sizeof(*info_aux), GFP_KERNEL | __GFP_NOWARN);
14239 	if (!info_aux)
14240 		goto err_free;
14241 
14242 	for (i = 0; i < nfuncs; i++) {
14243 		ret = bpf_check_uarg_tail_zero(urecord, krec_size, urec_size);
14244 		if (ret) {
14245 			if (ret == -E2BIG) {
14246 				verbose(env, "nonzero tailing record in func info");
14247 				/* set the size kernel expects so loader can zero
14248 				 * out the rest of the record.
14249 				 */
14250 				if (copy_to_bpfptr_offset(uattr,
14251 							  offsetof(union bpf_attr, func_info_rec_size),
14252 							  &min_size, sizeof(min_size)))
14253 					ret = -EFAULT;
14254 			}
14255 			goto err_free;
14256 		}
14257 
14258 		if (copy_from_bpfptr(&krecord[i], urecord, min_size)) {
14259 			ret = -EFAULT;
14260 			goto err_free;
14261 		}
14262 
14263 		/* check insn_off */
14264 		ret = -EINVAL;
14265 		if (i == 0) {
14266 			if (krecord[i].insn_off) {
14267 				verbose(env,
14268 					"nonzero insn_off %u for the first func info record",
14269 					krecord[i].insn_off);
14270 				goto err_free;
14271 			}
14272 		} else if (krecord[i].insn_off <= prev_offset) {
14273 			verbose(env,
14274 				"same or smaller insn offset (%u) than previous func info record (%u)",
14275 				krecord[i].insn_off, prev_offset);
14276 			goto err_free;
14277 		}
14278 
14279 		if (env->subprog_info[i].start != krecord[i].insn_off) {
14280 			verbose(env, "func_info BTF section doesn't match subprog layout in BPF program\n");
14281 			goto err_free;
14282 		}
14283 
14284 		/* check type_id */
14285 		type = btf_type_by_id(btf, krecord[i].type_id);
14286 		if (!type || !btf_type_is_func(type)) {
14287 			verbose(env, "invalid type id %d in func info",
14288 				krecord[i].type_id);
14289 			goto err_free;
14290 		}
14291 		info_aux[i].linkage = BTF_INFO_VLEN(type->info);
14292 
14293 		func_proto = btf_type_by_id(btf, type->type);
14294 		if (unlikely(!func_proto || !btf_type_is_func_proto(func_proto)))
14295 			/* btf_func_check() already verified it during BTF load */
14296 			goto err_free;
14297 		ret_type = btf_type_skip_modifiers(btf, func_proto->type, NULL);
14298 		scalar_return =
14299 			btf_type_is_small_int(ret_type) || btf_is_any_enum(ret_type);
14300 		if (i && !scalar_return && env->subprog_info[i].has_ld_abs) {
14301 			verbose(env, "LD_ABS is only allowed in functions that return 'int'.\n");
14302 			goto err_free;
14303 		}
14304 		if (i && !scalar_return && env->subprog_info[i].has_tail_call) {
14305 			verbose(env, "tail_call is only allowed in functions that return 'int'.\n");
14306 			goto err_free;
14307 		}
14308 
14309 		prev_offset = krecord[i].insn_off;
14310 		bpfptr_add(&urecord, urec_size);
14311 	}
14312 
14313 	prog->aux->func_info = krecord;
14314 	prog->aux->func_info_cnt = nfuncs;
14315 	prog->aux->func_info_aux = info_aux;
14316 	return 0;
14317 
14318 err_free:
14319 	kvfree(krecord);
14320 	kfree(info_aux);
14321 	return ret;
14322 }
14323 
14324 static void adjust_btf_func(struct bpf_verifier_env *env)
14325 {
14326 	struct bpf_prog_aux *aux = env->prog->aux;
14327 	int i;
14328 
14329 	if (!aux->func_info)
14330 		return;
14331 
14332 	for (i = 0; i < env->subprog_cnt; i++)
14333 		aux->func_info[i].insn_off = env->subprog_info[i].start;
14334 }
14335 
14336 #define MIN_BPF_LINEINFO_SIZE	offsetofend(struct bpf_line_info, line_col)
14337 #define MAX_LINEINFO_REC_SIZE	MAX_FUNCINFO_REC_SIZE
14338 
14339 static int check_btf_line(struct bpf_verifier_env *env,
14340 			  const union bpf_attr *attr,
14341 			  bpfptr_t uattr)
14342 {
14343 	u32 i, s, nr_linfo, ncopy, expected_size, rec_size, prev_offset = 0;
14344 	struct bpf_subprog_info *sub;
14345 	struct bpf_line_info *linfo;
14346 	struct bpf_prog *prog;
14347 	const struct btf *btf;
14348 	bpfptr_t ulinfo;
14349 	int err;
14350 
14351 	nr_linfo = attr->line_info_cnt;
14352 	if (!nr_linfo)
14353 		return 0;
14354 	if (nr_linfo > INT_MAX / sizeof(struct bpf_line_info))
14355 		return -EINVAL;
14356 
14357 	rec_size = attr->line_info_rec_size;
14358 	if (rec_size < MIN_BPF_LINEINFO_SIZE ||
14359 	    rec_size > MAX_LINEINFO_REC_SIZE ||
14360 	    rec_size & (sizeof(u32) - 1))
14361 		return -EINVAL;
14362 
14363 	/* Need to zero it in case the userspace may
14364 	 * pass in a smaller bpf_line_info object.
14365 	 */
14366 	linfo = kvcalloc(nr_linfo, sizeof(struct bpf_line_info),
14367 			 GFP_KERNEL | __GFP_NOWARN);
14368 	if (!linfo)
14369 		return -ENOMEM;
14370 
14371 	prog = env->prog;
14372 	btf = prog->aux->btf;
14373 
14374 	s = 0;
14375 	sub = env->subprog_info;
14376 	ulinfo = make_bpfptr(attr->line_info, uattr.is_kernel);
14377 	expected_size = sizeof(struct bpf_line_info);
14378 	ncopy = min_t(u32, expected_size, rec_size);
14379 	for (i = 0; i < nr_linfo; i++) {
14380 		err = bpf_check_uarg_tail_zero(ulinfo, expected_size, rec_size);
14381 		if (err) {
14382 			if (err == -E2BIG) {
14383 				verbose(env, "nonzero tailing record in line_info");
14384 				if (copy_to_bpfptr_offset(uattr,
14385 							  offsetof(union bpf_attr, line_info_rec_size),
14386 							  &expected_size, sizeof(expected_size)))
14387 					err = -EFAULT;
14388 			}
14389 			goto err_free;
14390 		}
14391 
14392 		if (copy_from_bpfptr(&linfo[i], ulinfo, ncopy)) {
14393 			err = -EFAULT;
14394 			goto err_free;
14395 		}
14396 
14397 		/*
14398 		 * Check insn_off to ensure
14399 		 * 1) strictly increasing AND
14400 		 * 2) bounded by prog->len
14401 		 *
14402 		 * The linfo[0].insn_off == 0 check logically falls into
14403 		 * the later "missing bpf_line_info for func..." case
14404 		 * because the first linfo[0].insn_off must be the
14405 		 * first sub also and the first sub must have
14406 		 * subprog_info[0].start == 0.
14407 		 */
14408 		if ((i && linfo[i].insn_off <= prev_offset) ||
14409 		    linfo[i].insn_off >= prog->len) {
14410 			verbose(env, "Invalid line_info[%u].insn_off:%u (prev_offset:%u prog->len:%u)\n",
14411 				i, linfo[i].insn_off, prev_offset,
14412 				prog->len);
14413 			err = -EINVAL;
14414 			goto err_free;
14415 		}
14416 
14417 		if (!prog->insnsi[linfo[i].insn_off].code) {
14418 			verbose(env,
14419 				"Invalid insn code at line_info[%u].insn_off\n",
14420 				i);
14421 			err = -EINVAL;
14422 			goto err_free;
14423 		}
14424 
14425 		if (!btf_name_by_offset(btf, linfo[i].line_off) ||
14426 		    !btf_name_by_offset(btf, linfo[i].file_name_off)) {
14427 			verbose(env, "Invalid line_info[%u].line_off or .file_name_off\n", i);
14428 			err = -EINVAL;
14429 			goto err_free;
14430 		}
14431 
14432 		if (s != env->subprog_cnt) {
14433 			if (linfo[i].insn_off == sub[s].start) {
14434 				sub[s].linfo_idx = i;
14435 				s++;
14436 			} else if (sub[s].start < linfo[i].insn_off) {
14437 				verbose(env, "missing bpf_line_info for func#%u\n", s);
14438 				err = -EINVAL;
14439 				goto err_free;
14440 			}
14441 		}
14442 
14443 		prev_offset = linfo[i].insn_off;
14444 		bpfptr_add(&ulinfo, rec_size);
14445 	}
14446 
14447 	if (s != env->subprog_cnt) {
14448 		verbose(env, "missing bpf_line_info for %u funcs starting from func#%u\n",
14449 			env->subprog_cnt - s, s);
14450 		err = -EINVAL;
14451 		goto err_free;
14452 	}
14453 
14454 	prog->aux->linfo = linfo;
14455 	prog->aux->nr_linfo = nr_linfo;
14456 
14457 	return 0;
14458 
14459 err_free:
14460 	kvfree(linfo);
14461 	return err;
14462 }
14463 
14464 #define MIN_CORE_RELO_SIZE	sizeof(struct bpf_core_relo)
14465 #define MAX_CORE_RELO_SIZE	MAX_FUNCINFO_REC_SIZE
14466 
14467 static int check_core_relo(struct bpf_verifier_env *env,
14468 			   const union bpf_attr *attr,
14469 			   bpfptr_t uattr)
14470 {
14471 	u32 i, nr_core_relo, ncopy, expected_size, rec_size;
14472 	struct bpf_core_relo core_relo = {};
14473 	struct bpf_prog *prog = env->prog;
14474 	const struct btf *btf = prog->aux->btf;
14475 	struct bpf_core_ctx ctx = {
14476 		.log = &env->log,
14477 		.btf = btf,
14478 	};
14479 	bpfptr_t u_core_relo;
14480 	int err;
14481 
14482 	nr_core_relo = attr->core_relo_cnt;
14483 	if (!nr_core_relo)
14484 		return 0;
14485 	if (nr_core_relo > INT_MAX / sizeof(struct bpf_core_relo))
14486 		return -EINVAL;
14487 
14488 	rec_size = attr->core_relo_rec_size;
14489 	if (rec_size < MIN_CORE_RELO_SIZE ||
14490 	    rec_size > MAX_CORE_RELO_SIZE ||
14491 	    rec_size % sizeof(u32))
14492 		return -EINVAL;
14493 
14494 	u_core_relo = make_bpfptr(attr->core_relos, uattr.is_kernel);
14495 	expected_size = sizeof(struct bpf_core_relo);
14496 	ncopy = min_t(u32, expected_size, rec_size);
14497 
14498 	/* Unlike func_info and line_info, copy and apply each CO-RE
14499 	 * relocation record one at a time.
14500 	 */
14501 	for (i = 0; i < nr_core_relo; i++) {
14502 		/* future proofing when sizeof(bpf_core_relo) changes */
14503 		err = bpf_check_uarg_tail_zero(u_core_relo, expected_size, rec_size);
14504 		if (err) {
14505 			if (err == -E2BIG) {
14506 				verbose(env, "nonzero tailing record in core_relo");
14507 				if (copy_to_bpfptr_offset(uattr,
14508 							  offsetof(union bpf_attr, core_relo_rec_size),
14509 							  &expected_size, sizeof(expected_size)))
14510 					err = -EFAULT;
14511 			}
14512 			break;
14513 		}
14514 
14515 		if (copy_from_bpfptr(&core_relo, u_core_relo, ncopy)) {
14516 			err = -EFAULT;
14517 			break;
14518 		}
14519 
14520 		if (core_relo.insn_off % 8 || core_relo.insn_off / 8 >= prog->len) {
14521 			verbose(env, "Invalid core_relo[%u].insn_off:%u prog->len:%u\n",
14522 				i, core_relo.insn_off, prog->len);
14523 			err = -EINVAL;
14524 			break;
14525 		}
14526 
14527 		err = bpf_core_apply(&ctx, &core_relo, i,
14528 				     &prog->insnsi[core_relo.insn_off / 8]);
14529 		if (err)
14530 			break;
14531 		bpfptr_add(&u_core_relo, rec_size);
14532 	}
14533 	return err;
14534 }
14535 
14536 static int check_btf_info(struct bpf_verifier_env *env,
14537 			  const union bpf_attr *attr,
14538 			  bpfptr_t uattr)
14539 {
14540 	struct btf *btf;
14541 	int err;
14542 
14543 	if (!attr->func_info_cnt && !attr->line_info_cnt) {
14544 		if (check_abnormal_return(env))
14545 			return -EINVAL;
14546 		return 0;
14547 	}
14548 
14549 	btf = btf_get_by_fd(attr->prog_btf_fd);
14550 	if (IS_ERR(btf))
14551 		return PTR_ERR(btf);
14552 	if (btf_is_kernel(btf)) {
14553 		btf_put(btf);
14554 		return -EACCES;
14555 	}
14556 	env->prog->aux->btf = btf;
14557 
14558 	err = check_btf_func(env, attr, uattr);
14559 	if (err)
14560 		return err;
14561 
14562 	err = check_btf_line(env, attr, uattr);
14563 	if (err)
14564 		return err;
14565 
14566 	err = check_core_relo(env, attr, uattr);
14567 	if (err)
14568 		return err;
14569 
14570 	return 0;
14571 }
14572 
14573 /* check %cur's range satisfies %old's */
14574 static bool range_within(struct bpf_reg_state *old,
14575 			 struct bpf_reg_state *cur)
14576 {
14577 	return old->umin_value <= cur->umin_value &&
14578 	       old->umax_value >= cur->umax_value &&
14579 	       old->smin_value <= cur->smin_value &&
14580 	       old->smax_value >= cur->smax_value &&
14581 	       old->u32_min_value <= cur->u32_min_value &&
14582 	       old->u32_max_value >= cur->u32_max_value &&
14583 	       old->s32_min_value <= cur->s32_min_value &&
14584 	       old->s32_max_value >= cur->s32_max_value;
14585 }
14586 
14587 /* If in the old state two registers had the same id, then they need to have
14588  * the same id in the new state as well.  But that id could be different from
14589  * the old state, so we need to track the mapping from old to new ids.
14590  * Once we have seen that, say, a reg with old id 5 had new id 9, any subsequent
14591  * regs with old id 5 must also have new id 9 for the new state to be safe.  But
14592  * regs with a different old id could still have new id 9, we don't care about
14593  * that.
14594  * So we look through our idmap to see if this old id has been seen before.  If
14595  * so, we require the new id to match; otherwise, we add the id pair to the map.
14596  */
14597 static bool check_ids(u32 old_id, u32 cur_id, struct bpf_id_pair *idmap)
14598 {
14599 	unsigned int i;
14600 
14601 	/* either both IDs should be set or both should be zero */
14602 	if (!!old_id != !!cur_id)
14603 		return false;
14604 
14605 	if (old_id == 0) /* cur_id == 0 as well */
14606 		return true;
14607 
14608 	for (i = 0; i < BPF_ID_MAP_SIZE; i++) {
14609 		if (!idmap[i].old) {
14610 			/* Reached an empty slot; haven't seen this id before */
14611 			idmap[i].old = old_id;
14612 			idmap[i].cur = cur_id;
14613 			return true;
14614 		}
14615 		if (idmap[i].old == old_id)
14616 			return idmap[i].cur == cur_id;
14617 	}
14618 	/* We ran out of idmap slots, which should be impossible */
14619 	WARN_ON_ONCE(1);
14620 	return false;
14621 }
14622 
14623 static void clean_func_state(struct bpf_verifier_env *env,
14624 			     struct bpf_func_state *st)
14625 {
14626 	enum bpf_reg_liveness live;
14627 	int i, j;
14628 
14629 	for (i = 0; i < BPF_REG_FP; i++) {
14630 		live = st->regs[i].live;
14631 		/* liveness must not touch this register anymore */
14632 		st->regs[i].live |= REG_LIVE_DONE;
14633 		if (!(live & REG_LIVE_READ))
14634 			/* since the register is unused, clear its state
14635 			 * to make further comparison simpler
14636 			 */
14637 			__mark_reg_not_init(env, &st->regs[i]);
14638 	}
14639 
14640 	for (i = 0; i < st->allocated_stack / BPF_REG_SIZE; i++) {
14641 		live = st->stack[i].spilled_ptr.live;
14642 		/* liveness must not touch this stack slot anymore */
14643 		st->stack[i].spilled_ptr.live |= REG_LIVE_DONE;
14644 		if (!(live & REG_LIVE_READ)) {
14645 			__mark_reg_not_init(env, &st->stack[i].spilled_ptr);
14646 			for (j = 0; j < BPF_REG_SIZE; j++)
14647 				st->stack[i].slot_type[j] = STACK_INVALID;
14648 		}
14649 	}
14650 }
14651 
14652 static void clean_verifier_state(struct bpf_verifier_env *env,
14653 				 struct bpf_verifier_state *st)
14654 {
14655 	int i;
14656 
14657 	if (st->frame[0]->regs[0].live & REG_LIVE_DONE)
14658 		/* all regs in this state in all frames were already marked */
14659 		return;
14660 
14661 	for (i = 0; i <= st->curframe; i++)
14662 		clean_func_state(env, st->frame[i]);
14663 }
14664 
14665 /* the parentage chains form a tree.
14666  * the verifier states are added to state lists at given insn and
14667  * pushed into state stack for future exploration.
14668  * when the verifier reaches bpf_exit insn some of the verifer states
14669  * stored in the state lists have their final liveness state already,
14670  * but a lot of states will get revised from liveness point of view when
14671  * the verifier explores other branches.
14672  * Example:
14673  * 1: r0 = 1
14674  * 2: if r1 == 100 goto pc+1
14675  * 3: r0 = 2
14676  * 4: exit
14677  * when the verifier reaches exit insn the register r0 in the state list of
14678  * insn 2 will be seen as !REG_LIVE_READ. Then the verifier pops the other_branch
14679  * of insn 2 and goes exploring further. At the insn 4 it will walk the
14680  * parentage chain from insn 4 into insn 2 and will mark r0 as REG_LIVE_READ.
14681  *
14682  * Since the verifier pushes the branch states as it sees them while exploring
14683  * the program the condition of walking the branch instruction for the second
14684  * time means that all states below this branch were already explored and
14685  * their final liveness marks are already propagated.
14686  * Hence when the verifier completes the search of state list in is_state_visited()
14687  * we can call this clean_live_states() function to mark all liveness states
14688  * as REG_LIVE_DONE to indicate that 'parent' pointers of 'struct bpf_reg_state'
14689  * will not be used.
14690  * This function also clears the registers and stack for states that !READ
14691  * to simplify state merging.
14692  *
14693  * Important note here that walking the same branch instruction in the callee
14694  * doesn't meant that the states are DONE. The verifier has to compare
14695  * the callsites
14696  */
14697 static void clean_live_states(struct bpf_verifier_env *env, int insn,
14698 			      struct bpf_verifier_state *cur)
14699 {
14700 	struct bpf_verifier_state_list *sl;
14701 	int i;
14702 
14703 	sl = *explored_state(env, insn);
14704 	while (sl) {
14705 		if (sl->state.branches)
14706 			goto next;
14707 		if (sl->state.insn_idx != insn ||
14708 		    sl->state.curframe != cur->curframe)
14709 			goto next;
14710 		for (i = 0; i <= cur->curframe; i++)
14711 			if (sl->state.frame[i]->callsite != cur->frame[i]->callsite)
14712 				goto next;
14713 		clean_verifier_state(env, &sl->state);
14714 next:
14715 		sl = sl->next;
14716 	}
14717 }
14718 
14719 static bool regs_exact(const struct bpf_reg_state *rold,
14720 		       const struct bpf_reg_state *rcur,
14721 		       struct bpf_id_pair *idmap)
14722 {
14723 	return memcmp(rold, rcur, offsetof(struct bpf_reg_state, id)) == 0 &&
14724 	       check_ids(rold->id, rcur->id, idmap) &&
14725 	       check_ids(rold->ref_obj_id, rcur->ref_obj_id, idmap);
14726 }
14727 
14728 /* Returns true if (rold safe implies rcur safe) */
14729 static bool regsafe(struct bpf_verifier_env *env, struct bpf_reg_state *rold,
14730 		    struct bpf_reg_state *rcur, struct bpf_id_pair *idmap)
14731 {
14732 	if (!(rold->live & REG_LIVE_READ))
14733 		/* explored state didn't use this */
14734 		return true;
14735 	if (rold->type == NOT_INIT)
14736 		/* explored state can't have used this */
14737 		return true;
14738 	if (rcur->type == NOT_INIT)
14739 		return false;
14740 
14741 	/* Enforce that register types have to match exactly, including their
14742 	 * modifiers (like PTR_MAYBE_NULL, MEM_RDONLY, etc), as a general
14743 	 * rule.
14744 	 *
14745 	 * One can make a point that using a pointer register as unbounded
14746 	 * SCALAR would be technically acceptable, but this could lead to
14747 	 * pointer leaks because scalars are allowed to leak while pointers
14748 	 * are not. We could make this safe in special cases if root is
14749 	 * calling us, but it's probably not worth the hassle.
14750 	 *
14751 	 * Also, register types that are *not* MAYBE_NULL could technically be
14752 	 * safe to use as their MAYBE_NULL variants (e.g., PTR_TO_MAP_VALUE
14753 	 * is safe to be used as PTR_TO_MAP_VALUE_OR_NULL, provided both point
14754 	 * to the same map).
14755 	 * However, if the old MAYBE_NULL register then got NULL checked,
14756 	 * doing so could have affected others with the same id, and we can't
14757 	 * check for that because we lost the id when we converted to
14758 	 * a non-MAYBE_NULL variant.
14759 	 * So, as a general rule we don't allow mixing MAYBE_NULL and
14760 	 * non-MAYBE_NULL registers as well.
14761 	 */
14762 	if (rold->type != rcur->type)
14763 		return false;
14764 
14765 	switch (base_type(rold->type)) {
14766 	case SCALAR_VALUE:
14767 		if (regs_exact(rold, rcur, idmap))
14768 			return true;
14769 		if (env->explore_alu_limits)
14770 			return false;
14771 		if (!rold->precise)
14772 			return true;
14773 		/* new val must satisfy old val knowledge */
14774 		return range_within(rold, rcur) &&
14775 		       tnum_in(rold->var_off, rcur->var_off);
14776 	case PTR_TO_MAP_KEY:
14777 	case PTR_TO_MAP_VALUE:
14778 	case PTR_TO_MEM:
14779 	case PTR_TO_BUF:
14780 	case PTR_TO_TP_BUFFER:
14781 		/* If the new min/max/var_off satisfy the old ones and
14782 		 * everything else matches, we are OK.
14783 		 */
14784 		return memcmp(rold, rcur, offsetof(struct bpf_reg_state, var_off)) == 0 &&
14785 		       range_within(rold, rcur) &&
14786 		       tnum_in(rold->var_off, rcur->var_off) &&
14787 		       check_ids(rold->id, rcur->id, idmap) &&
14788 		       check_ids(rold->ref_obj_id, rcur->ref_obj_id, idmap);
14789 	case PTR_TO_PACKET_META:
14790 	case PTR_TO_PACKET:
14791 		/* We must have at least as much range as the old ptr
14792 		 * did, so that any accesses which were safe before are
14793 		 * still safe.  This is true even if old range < old off,
14794 		 * since someone could have accessed through (ptr - k), or
14795 		 * even done ptr -= k in a register, to get a safe access.
14796 		 */
14797 		if (rold->range > rcur->range)
14798 			return false;
14799 		/* If the offsets don't match, we can't trust our alignment;
14800 		 * nor can we be sure that we won't fall out of range.
14801 		 */
14802 		if (rold->off != rcur->off)
14803 			return false;
14804 		/* id relations must be preserved */
14805 		if (!check_ids(rold->id, rcur->id, idmap))
14806 			return false;
14807 		/* new val must satisfy old val knowledge */
14808 		return range_within(rold, rcur) &&
14809 		       tnum_in(rold->var_off, rcur->var_off);
14810 	case PTR_TO_STACK:
14811 		/* two stack pointers are equal only if they're pointing to
14812 		 * the same stack frame, since fp-8 in foo != fp-8 in bar
14813 		 */
14814 		return regs_exact(rold, rcur, idmap) && rold->frameno == rcur->frameno;
14815 	default:
14816 		return regs_exact(rold, rcur, idmap);
14817 	}
14818 }
14819 
14820 static bool stacksafe(struct bpf_verifier_env *env, struct bpf_func_state *old,
14821 		      struct bpf_func_state *cur, struct bpf_id_pair *idmap)
14822 {
14823 	int i, spi;
14824 
14825 	/* walk slots of the explored stack and ignore any additional
14826 	 * slots in the current stack, since explored(safe) state
14827 	 * didn't use them
14828 	 */
14829 	for (i = 0; i < old->allocated_stack; i++) {
14830 		struct bpf_reg_state *old_reg, *cur_reg;
14831 
14832 		spi = i / BPF_REG_SIZE;
14833 
14834 		if (!(old->stack[spi].spilled_ptr.live & REG_LIVE_READ)) {
14835 			i += BPF_REG_SIZE - 1;
14836 			/* explored state didn't use this */
14837 			continue;
14838 		}
14839 
14840 		if (old->stack[spi].slot_type[i % BPF_REG_SIZE] == STACK_INVALID)
14841 			continue;
14842 
14843 		if (env->allow_uninit_stack &&
14844 		    old->stack[spi].slot_type[i % BPF_REG_SIZE] == STACK_MISC)
14845 			continue;
14846 
14847 		/* explored stack has more populated slots than current stack
14848 		 * and these slots were used
14849 		 */
14850 		if (i >= cur->allocated_stack)
14851 			return false;
14852 
14853 		/* if old state was safe with misc data in the stack
14854 		 * it will be safe with zero-initialized stack.
14855 		 * The opposite is not true
14856 		 */
14857 		if (old->stack[spi].slot_type[i % BPF_REG_SIZE] == STACK_MISC &&
14858 		    cur->stack[spi].slot_type[i % BPF_REG_SIZE] == STACK_ZERO)
14859 			continue;
14860 		if (old->stack[spi].slot_type[i % BPF_REG_SIZE] !=
14861 		    cur->stack[spi].slot_type[i % BPF_REG_SIZE])
14862 			/* Ex: old explored (safe) state has STACK_SPILL in
14863 			 * this stack slot, but current has STACK_MISC ->
14864 			 * this verifier states are not equivalent,
14865 			 * return false to continue verification of this path
14866 			 */
14867 			return false;
14868 		if (i % BPF_REG_SIZE != BPF_REG_SIZE - 1)
14869 			continue;
14870 		/* Both old and cur are having same slot_type */
14871 		switch (old->stack[spi].slot_type[BPF_REG_SIZE - 1]) {
14872 		case STACK_SPILL:
14873 			/* when explored and current stack slot are both storing
14874 			 * spilled registers, check that stored pointers types
14875 			 * are the same as well.
14876 			 * Ex: explored safe path could have stored
14877 			 * (bpf_reg_state) {.type = PTR_TO_STACK, .off = -8}
14878 			 * but current path has stored:
14879 			 * (bpf_reg_state) {.type = PTR_TO_STACK, .off = -16}
14880 			 * such verifier states are not equivalent.
14881 			 * return false to continue verification of this path
14882 			 */
14883 			if (!regsafe(env, &old->stack[spi].spilled_ptr,
14884 				     &cur->stack[spi].spilled_ptr, idmap))
14885 				return false;
14886 			break;
14887 		case STACK_DYNPTR:
14888 			old_reg = &old->stack[spi].spilled_ptr;
14889 			cur_reg = &cur->stack[spi].spilled_ptr;
14890 			if (old_reg->dynptr.type != cur_reg->dynptr.type ||
14891 			    old_reg->dynptr.first_slot != cur_reg->dynptr.first_slot ||
14892 			    !check_ids(old_reg->ref_obj_id, cur_reg->ref_obj_id, idmap))
14893 				return false;
14894 			break;
14895 		case STACK_ITER:
14896 			old_reg = &old->stack[spi].spilled_ptr;
14897 			cur_reg = &cur->stack[spi].spilled_ptr;
14898 			/* iter.depth is not compared between states as it
14899 			 * doesn't matter for correctness and would otherwise
14900 			 * prevent convergence; we maintain it only to prevent
14901 			 * infinite loop check triggering, see
14902 			 * iter_active_depths_differ()
14903 			 */
14904 			if (old_reg->iter.btf != cur_reg->iter.btf ||
14905 			    old_reg->iter.btf_id != cur_reg->iter.btf_id ||
14906 			    old_reg->iter.state != cur_reg->iter.state ||
14907 			    /* ignore {old_reg,cur_reg}->iter.depth, see above */
14908 			    !check_ids(old_reg->ref_obj_id, cur_reg->ref_obj_id, idmap))
14909 				return false;
14910 			break;
14911 		case STACK_MISC:
14912 		case STACK_ZERO:
14913 		case STACK_INVALID:
14914 			continue;
14915 		/* Ensure that new unhandled slot types return false by default */
14916 		default:
14917 			return false;
14918 		}
14919 	}
14920 	return true;
14921 }
14922 
14923 static bool refsafe(struct bpf_func_state *old, struct bpf_func_state *cur,
14924 		    struct bpf_id_pair *idmap)
14925 {
14926 	int i;
14927 
14928 	if (old->acquired_refs != cur->acquired_refs)
14929 		return false;
14930 
14931 	for (i = 0; i < old->acquired_refs; i++) {
14932 		if (!check_ids(old->refs[i].id, cur->refs[i].id, idmap))
14933 			return false;
14934 	}
14935 
14936 	return true;
14937 }
14938 
14939 /* compare two verifier states
14940  *
14941  * all states stored in state_list are known to be valid, since
14942  * verifier reached 'bpf_exit' instruction through them
14943  *
14944  * this function is called when verifier exploring different branches of
14945  * execution popped from the state stack. If it sees an old state that has
14946  * more strict register state and more strict stack state then this execution
14947  * branch doesn't need to be explored further, since verifier already
14948  * concluded that more strict state leads to valid finish.
14949  *
14950  * Therefore two states are equivalent if register state is more conservative
14951  * and explored stack state is more conservative than the current one.
14952  * Example:
14953  *       explored                   current
14954  * (slot1=INV slot2=MISC) == (slot1=MISC slot2=MISC)
14955  * (slot1=MISC slot2=MISC) != (slot1=INV slot2=MISC)
14956  *
14957  * In other words if current stack state (one being explored) has more
14958  * valid slots than old one that already passed validation, it means
14959  * the verifier can stop exploring and conclude that current state is valid too
14960  *
14961  * Similarly with registers. If explored state has register type as invalid
14962  * whereas register type in current state is meaningful, it means that
14963  * the current state will reach 'bpf_exit' instruction safely
14964  */
14965 static bool func_states_equal(struct bpf_verifier_env *env, struct bpf_func_state *old,
14966 			      struct bpf_func_state *cur)
14967 {
14968 	int i;
14969 
14970 	for (i = 0; i < MAX_BPF_REG; i++)
14971 		if (!regsafe(env, &old->regs[i], &cur->regs[i],
14972 			     env->idmap_scratch))
14973 			return false;
14974 
14975 	if (!stacksafe(env, old, cur, env->idmap_scratch))
14976 		return false;
14977 
14978 	if (!refsafe(old, cur, env->idmap_scratch))
14979 		return false;
14980 
14981 	return true;
14982 }
14983 
14984 static bool states_equal(struct bpf_verifier_env *env,
14985 			 struct bpf_verifier_state *old,
14986 			 struct bpf_verifier_state *cur)
14987 {
14988 	int i;
14989 
14990 	if (old->curframe != cur->curframe)
14991 		return false;
14992 
14993 	memset(env->idmap_scratch, 0, sizeof(env->idmap_scratch));
14994 
14995 	/* Verification state from speculative execution simulation
14996 	 * must never prune a non-speculative execution one.
14997 	 */
14998 	if (old->speculative && !cur->speculative)
14999 		return false;
15000 
15001 	if (old->active_lock.ptr != cur->active_lock.ptr)
15002 		return false;
15003 
15004 	/* Old and cur active_lock's have to be either both present
15005 	 * or both absent.
15006 	 */
15007 	if (!!old->active_lock.id != !!cur->active_lock.id)
15008 		return false;
15009 
15010 	if (old->active_lock.id &&
15011 	    !check_ids(old->active_lock.id, cur->active_lock.id, env->idmap_scratch))
15012 		return false;
15013 
15014 	if (old->active_rcu_lock != cur->active_rcu_lock)
15015 		return false;
15016 
15017 	/* for states to be equal callsites have to be the same
15018 	 * and all frame states need to be equivalent
15019 	 */
15020 	for (i = 0; i <= old->curframe; i++) {
15021 		if (old->frame[i]->callsite != cur->frame[i]->callsite)
15022 			return false;
15023 		if (!func_states_equal(env, old->frame[i], cur->frame[i]))
15024 			return false;
15025 	}
15026 	return true;
15027 }
15028 
15029 /* Return 0 if no propagation happened. Return negative error code if error
15030  * happened. Otherwise, return the propagated bit.
15031  */
15032 static int propagate_liveness_reg(struct bpf_verifier_env *env,
15033 				  struct bpf_reg_state *reg,
15034 				  struct bpf_reg_state *parent_reg)
15035 {
15036 	u8 parent_flag = parent_reg->live & REG_LIVE_READ;
15037 	u8 flag = reg->live & REG_LIVE_READ;
15038 	int err;
15039 
15040 	/* When comes here, read flags of PARENT_REG or REG could be any of
15041 	 * REG_LIVE_READ64, REG_LIVE_READ32, REG_LIVE_NONE. There is no need
15042 	 * of propagation if PARENT_REG has strongest REG_LIVE_READ64.
15043 	 */
15044 	if (parent_flag == REG_LIVE_READ64 ||
15045 	    /* Or if there is no read flag from REG. */
15046 	    !flag ||
15047 	    /* Or if the read flag from REG is the same as PARENT_REG. */
15048 	    parent_flag == flag)
15049 		return 0;
15050 
15051 	err = mark_reg_read(env, reg, parent_reg, flag);
15052 	if (err)
15053 		return err;
15054 
15055 	return flag;
15056 }
15057 
15058 /* A write screens off any subsequent reads; but write marks come from the
15059  * straight-line code between a state and its parent.  When we arrive at an
15060  * equivalent state (jump target or such) we didn't arrive by the straight-line
15061  * code, so read marks in the state must propagate to the parent regardless
15062  * of the state's write marks. That's what 'parent == state->parent' comparison
15063  * in mark_reg_read() is for.
15064  */
15065 static int propagate_liveness(struct bpf_verifier_env *env,
15066 			      const struct bpf_verifier_state *vstate,
15067 			      struct bpf_verifier_state *vparent)
15068 {
15069 	struct bpf_reg_state *state_reg, *parent_reg;
15070 	struct bpf_func_state *state, *parent;
15071 	int i, frame, err = 0;
15072 
15073 	if (vparent->curframe != vstate->curframe) {
15074 		WARN(1, "propagate_live: parent frame %d current frame %d\n",
15075 		     vparent->curframe, vstate->curframe);
15076 		return -EFAULT;
15077 	}
15078 	/* Propagate read liveness of registers... */
15079 	BUILD_BUG_ON(BPF_REG_FP + 1 != MAX_BPF_REG);
15080 	for (frame = 0; frame <= vstate->curframe; frame++) {
15081 		parent = vparent->frame[frame];
15082 		state = vstate->frame[frame];
15083 		parent_reg = parent->regs;
15084 		state_reg = state->regs;
15085 		/* We don't need to worry about FP liveness, it's read-only */
15086 		for (i = frame < vstate->curframe ? BPF_REG_6 : 0; i < BPF_REG_FP; i++) {
15087 			err = propagate_liveness_reg(env, &state_reg[i],
15088 						     &parent_reg[i]);
15089 			if (err < 0)
15090 				return err;
15091 			if (err == REG_LIVE_READ64)
15092 				mark_insn_zext(env, &parent_reg[i]);
15093 		}
15094 
15095 		/* Propagate stack slots. */
15096 		for (i = 0; i < state->allocated_stack / BPF_REG_SIZE &&
15097 			    i < parent->allocated_stack / BPF_REG_SIZE; i++) {
15098 			parent_reg = &parent->stack[i].spilled_ptr;
15099 			state_reg = &state->stack[i].spilled_ptr;
15100 			err = propagate_liveness_reg(env, state_reg,
15101 						     parent_reg);
15102 			if (err < 0)
15103 				return err;
15104 		}
15105 	}
15106 	return 0;
15107 }
15108 
15109 /* find precise scalars in the previous equivalent state and
15110  * propagate them into the current state
15111  */
15112 static int propagate_precision(struct bpf_verifier_env *env,
15113 			       const struct bpf_verifier_state *old)
15114 {
15115 	struct bpf_reg_state *state_reg;
15116 	struct bpf_func_state *state;
15117 	int i, err = 0, fr;
15118 
15119 	for (fr = old->curframe; fr >= 0; fr--) {
15120 		state = old->frame[fr];
15121 		state_reg = state->regs;
15122 		for (i = 0; i < BPF_REG_FP; i++, state_reg++) {
15123 			if (state_reg->type != SCALAR_VALUE ||
15124 			    !state_reg->precise ||
15125 			    !(state_reg->live & REG_LIVE_READ))
15126 				continue;
15127 			if (env->log.level & BPF_LOG_LEVEL2)
15128 				verbose(env, "frame %d: propagating r%d\n", fr, i);
15129 			err = mark_chain_precision_frame(env, fr, i);
15130 			if (err < 0)
15131 				return err;
15132 		}
15133 
15134 		for (i = 0; i < state->allocated_stack / BPF_REG_SIZE; i++) {
15135 			if (!is_spilled_reg(&state->stack[i]))
15136 				continue;
15137 			state_reg = &state->stack[i].spilled_ptr;
15138 			if (state_reg->type != SCALAR_VALUE ||
15139 			    !state_reg->precise ||
15140 			    !(state_reg->live & REG_LIVE_READ))
15141 				continue;
15142 			if (env->log.level & BPF_LOG_LEVEL2)
15143 				verbose(env, "frame %d: propagating fp%d\n",
15144 					fr, (-i - 1) * BPF_REG_SIZE);
15145 			err = mark_chain_precision_stack_frame(env, fr, i);
15146 			if (err < 0)
15147 				return err;
15148 		}
15149 	}
15150 	return 0;
15151 }
15152 
15153 static bool states_maybe_looping(struct bpf_verifier_state *old,
15154 				 struct bpf_verifier_state *cur)
15155 {
15156 	struct bpf_func_state *fold, *fcur;
15157 	int i, fr = cur->curframe;
15158 
15159 	if (old->curframe != fr)
15160 		return false;
15161 
15162 	fold = old->frame[fr];
15163 	fcur = cur->frame[fr];
15164 	for (i = 0; i < MAX_BPF_REG; i++)
15165 		if (memcmp(&fold->regs[i], &fcur->regs[i],
15166 			   offsetof(struct bpf_reg_state, parent)))
15167 			return false;
15168 	return true;
15169 }
15170 
15171 static bool is_iter_next_insn(struct bpf_verifier_env *env, int insn_idx)
15172 {
15173 	return env->insn_aux_data[insn_idx].is_iter_next;
15174 }
15175 
15176 /* is_state_visited() handles iter_next() (see process_iter_next_call() for
15177  * terminology) calls specially: as opposed to bounded BPF loops, it *expects*
15178  * states to match, which otherwise would look like an infinite loop. So while
15179  * iter_next() calls are taken care of, we still need to be careful and
15180  * prevent erroneous and too eager declaration of "ininite loop", when
15181  * iterators are involved.
15182  *
15183  * Here's a situation in pseudo-BPF assembly form:
15184  *
15185  *   0: again:                          ; set up iter_next() call args
15186  *   1:   r1 = &it                      ; <CHECKPOINT HERE>
15187  *   2:   call bpf_iter_num_next        ; this is iter_next() call
15188  *   3:   if r0 == 0 goto done
15189  *   4:   ... something useful here ...
15190  *   5:   goto again                    ; another iteration
15191  *   6: done:
15192  *   7:   r1 = &it
15193  *   8:   call bpf_iter_num_destroy     ; clean up iter state
15194  *   9:   exit
15195  *
15196  * This is a typical loop. Let's assume that we have a prune point at 1:,
15197  * before we get to `call bpf_iter_num_next` (e.g., because of that `goto
15198  * again`, assuming other heuristics don't get in a way).
15199  *
15200  * When we first time come to 1:, let's say we have some state X. We proceed
15201  * to 2:, fork states, enqueue ACTIVE, validate NULL case successfully, exit.
15202  * Now we come back to validate that forked ACTIVE state. We proceed through
15203  * 3-5, come to goto, jump to 1:. Let's assume our state didn't change, so we
15204  * are converging. But the problem is that we don't know that yet, as this
15205  * convergence has to happen at iter_next() call site only. So if nothing is
15206  * done, at 1: verifier will use bounded loop logic and declare infinite
15207  * looping (and would be *technically* correct, if not for iterator's
15208  * "eventual sticky NULL" contract, see process_iter_next_call()). But we
15209  * don't want that. So what we do in process_iter_next_call() when we go on
15210  * another ACTIVE iteration, we bump slot->iter.depth, to mark that it's
15211  * a different iteration. So when we suspect an infinite loop, we additionally
15212  * check if any of the *ACTIVE* iterator states depths differ. If yes, we
15213  * pretend we are not looping and wait for next iter_next() call.
15214  *
15215  * This only applies to ACTIVE state. In DRAINED state we don't expect to
15216  * loop, because that would actually mean infinite loop, as DRAINED state is
15217  * "sticky", and so we'll keep returning into the same instruction with the
15218  * same state (at least in one of possible code paths).
15219  *
15220  * This approach allows to keep infinite loop heuristic even in the face of
15221  * active iterator. E.g., C snippet below is and will be detected as
15222  * inifintely looping:
15223  *
15224  *   struct bpf_iter_num it;
15225  *   int *p, x;
15226  *
15227  *   bpf_iter_num_new(&it, 0, 10);
15228  *   while ((p = bpf_iter_num_next(&t))) {
15229  *       x = p;
15230  *       while (x--) {} // <<-- infinite loop here
15231  *   }
15232  *
15233  */
15234 static bool iter_active_depths_differ(struct bpf_verifier_state *old, struct bpf_verifier_state *cur)
15235 {
15236 	struct bpf_reg_state *slot, *cur_slot;
15237 	struct bpf_func_state *state;
15238 	int i, fr;
15239 
15240 	for (fr = old->curframe; fr >= 0; fr--) {
15241 		state = old->frame[fr];
15242 		for (i = 0; i < state->allocated_stack / BPF_REG_SIZE; i++) {
15243 			if (state->stack[i].slot_type[0] != STACK_ITER)
15244 				continue;
15245 
15246 			slot = &state->stack[i].spilled_ptr;
15247 			if (slot->iter.state != BPF_ITER_STATE_ACTIVE)
15248 				continue;
15249 
15250 			cur_slot = &cur->frame[fr]->stack[i].spilled_ptr;
15251 			if (cur_slot->iter.depth != slot->iter.depth)
15252 				return true;
15253 		}
15254 	}
15255 	return false;
15256 }
15257 
15258 static int is_state_visited(struct bpf_verifier_env *env, int insn_idx)
15259 {
15260 	struct bpf_verifier_state_list *new_sl;
15261 	struct bpf_verifier_state_list *sl, **pprev;
15262 	struct bpf_verifier_state *cur = env->cur_state, *new;
15263 	int i, j, err, states_cnt = 0;
15264 	bool force_new_state = env->test_state_freq || is_force_checkpoint(env, insn_idx);
15265 	bool add_new_state = force_new_state;
15266 
15267 	/* bpf progs typically have pruning point every 4 instructions
15268 	 * http://vger.kernel.org/bpfconf2019.html#session-1
15269 	 * Do not add new state for future pruning if the verifier hasn't seen
15270 	 * at least 2 jumps and at least 8 instructions.
15271 	 * This heuristics helps decrease 'total_states' and 'peak_states' metric.
15272 	 * In tests that amounts to up to 50% reduction into total verifier
15273 	 * memory consumption and 20% verifier time speedup.
15274 	 */
15275 	if (env->jmps_processed - env->prev_jmps_processed >= 2 &&
15276 	    env->insn_processed - env->prev_insn_processed >= 8)
15277 		add_new_state = true;
15278 
15279 	pprev = explored_state(env, insn_idx);
15280 	sl = *pprev;
15281 
15282 	clean_live_states(env, insn_idx, cur);
15283 
15284 	while (sl) {
15285 		states_cnt++;
15286 		if (sl->state.insn_idx != insn_idx)
15287 			goto next;
15288 
15289 		if (sl->state.branches) {
15290 			struct bpf_func_state *frame = sl->state.frame[sl->state.curframe];
15291 
15292 			if (frame->in_async_callback_fn &&
15293 			    frame->async_entry_cnt != cur->frame[cur->curframe]->async_entry_cnt) {
15294 				/* Different async_entry_cnt means that the verifier is
15295 				 * processing another entry into async callback.
15296 				 * Seeing the same state is not an indication of infinite
15297 				 * loop or infinite recursion.
15298 				 * But finding the same state doesn't mean that it's safe
15299 				 * to stop processing the current state. The previous state
15300 				 * hasn't yet reached bpf_exit, since state.branches > 0.
15301 				 * Checking in_async_callback_fn alone is not enough either.
15302 				 * Since the verifier still needs to catch infinite loops
15303 				 * inside async callbacks.
15304 				 */
15305 				goto skip_inf_loop_check;
15306 			}
15307 			/* BPF open-coded iterators loop detection is special.
15308 			 * states_maybe_looping() logic is too simplistic in detecting
15309 			 * states that *might* be equivalent, because it doesn't know
15310 			 * about ID remapping, so don't even perform it.
15311 			 * See process_iter_next_call() and iter_active_depths_differ()
15312 			 * for overview of the logic. When current and one of parent
15313 			 * states are detected as equivalent, it's a good thing: we prove
15314 			 * convergence and can stop simulating further iterations.
15315 			 * It's safe to assume that iterator loop will finish, taking into
15316 			 * account iter_next() contract of eventually returning
15317 			 * sticky NULL result.
15318 			 */
15319 			if (is_iter_next_insn(env, insn_idx)) {
15320 				if (states_equal(env, &sl->state, cur)) {
15321 					struct bpf_func_state *cur_frame;
15322 					struct bpf_reg_state *iter_state, *iter_reg;
15323 					int spi;
15324 
15325 					cur_frame = cur->frame[cur->curframe];
15326 					/* btf_check_iter_kfuncs() enforces that
15327 					 * iter state pointer is always the first arg
15328 					 */
15329 					iter_reg = &cur_frame->regs[BPF_REG_1];
15330 					/* current state is valid due to states_equal(),
15331 					 * so we can assume valid iter and reg state,
15332 					 * no need for extra (re-)validations
15333 					 */
15334 					spi = __get_spi(iter_reg->off + iter_reg->var_off.value);
15335 					iter_state = &func(env, iter_reg)->stack[spi].spilled_ptr;
15336 					if (iter_state->iter.state == BPF_ITER_STATE_ACTIVE)
15337 						goto hit;
15338 				}
15339 				goto skip_inf_loop_check;
15340 			}
15341 			/* attempt to detect infinite loop to avoid unnecessary doomed work */
15342 			if (states_maybe_looping(&sl->state, cur) &&
15343 			    states_equal(env, &sl->state, cur) &&
15344 			    !iter_active_depths_differ(&sl->state, cur)) {
15345 				verbose_linfo(env, insn_idx, "; ");
15346 				verbose(env, "infinite loop detected at insn %d\n", insn_idx);
15347 				return -EINVAL;
15348 			}
15349 			/* if the verifier is processing a loop, avoid adding new state
15350 			 * too often, since different loop iterations have distinct
15351 			 * states and may not help future pruning.
15352 			 * This threshold shouldn't be too low to make sure that
15353 			 * a loop with large bound will be rejected quickly.
15354 			 * The most abusive loop will be:
15355 			 * r1 += 1
15356 			 * if r1 < 1000000 goto pc-2
15357 			 * 1M insn_procssed limit / 100 == 10k peak states.
15358 			 * This threshold shouldn't be too high either, since states
15359 			 * at the end of the loop are likely to be useful in pruning.
15360 			 */
15361 skip_inf_loop_check:
15362 			if (!force_new_state &&
15363 			    env->jmps_processed - env->prev_jmps_processed < 20 &&
15364 			    env->insn_processed - env->prev_insn_processed < 100)
15365 				add_new_state = false;
15366 			goto miss;
15367 		}
15368 		if (states_equal(env, &sl->state, cur)) {
15369 hit:
15370 			sl->hit_cnt++;
15371 			/* reached equivalent register/stack state,
15372 			 * prune the search.
15373 			 * Registers read by the continuation are read by us.
15374 			 * If we have any write marks in env->cur_state, they
15375 			 * will prevent corresponding reads in the continuation
15376 			 * from reaching our parent (an explored_state).  Our
15377 			 * own state will get the read marks recorded, but
15378 			 * they'll be immediately forgotten as we're pruning
15379 			 * this state and will pop a new one.
15380 			 */
15381 			err = propagate_liveness(env, &sl->state, cur);
15382 
15383 			/* if previous state reached the exit with precision and
15384 			 * current state is equivalent to it (except precsion marks)
15385 			 * the precision needs to be propagated back in
15386 			 * the current state.
15387 			 */
15388 			err = err ? : push_jmp_history(env, cur);
15389 			err = err ? : propagate_precision(env, &sl->state);
15390 			if (err)
15391 				return err;
15392 			return 1;
15393 		}
15394 miss:
15395 		/* when new state is not going to be added do not increase miss count.
15396 		 * Otherwise several loop iterations will remove the state
15397 		 * recorded earlier. The goal of these heuristics is to have
15398 		 * states from some iterations of the loop (some in the beginning
15399 		 * and some at the end) to help pruning.
15400 		 */
15401 		if (add_new_state)
15402 			sl->miss_cnt++;
15403 		/* heuristic to determine whether this state is beneficial
15404 		 * to keep checking from state equivalence point of view.
15405 		 * Higher numbers increase max_states_per_insn and verification time,
15406 		 * but do not meaningfully decrease insn_processed.
15407 		 */
15408 		if (sl->miss_cnt > sl->hit_cnt * 3 + 3) {
15409 			/* the state is unlikely to be useful. Remove it to
15410 			 * speed up verification
15411 			 */
15412 			*pprev = sl->next;
15413 			if (sl->state.frame[0]->regs[0].live & REG_LIVE_DONE) {
15414 				u32 br = sl->state.branches;
15415 
15416 				WARN_ONCE(br,
15417 					  "BUG live_done but branches_to_explore %d\n",
15418 					  br);
15419 				free_verifier_state(&sl->state, false);
15420 				kfree(sl);
15421 				env->peak_states--;
15422 			} else {
15423 				/* cannot free this state, since parentage chain may
15424 				 * walk it later. Add it for free_list instead to
15425 				 * be freed at the end of verification
15426 				 */
15427 				sl->next = env->free_list;
15428 				env->free_list = sl;
15429 			}
15430 			sl = *pprev;
15431 			continue;
15432 		}
15433 next:
15434 		pprev = &sl->next;
15435 		sl = *pprev;
15436 	}
15437 
15438 	if (env->max_states_per_insn < states_cnt)
15439 		env->max_states_per_insn = states_cnt;
15440 
15441 	if (!env->bpf_capable && states_cnt > BPF_COMPLEXITY_LIMIT_STATES)
15442 		return 0;
15443 
15444 	if (!add_new_state)
15445 		return 0;
15446 
15447 	/* There were no equivalent states, remember the current one.
15448 	 * Technically the current state is not proven to be safe yet,
15449 	 * but it will either reach outer most bpf_exit (which means it's safe)
15450 	 * or it will be rejected. When there are no loops the verifier won't be
15451 	 * seeing this tuple (frame[0].callsite, frame[1].callsite, .. insn_idx)
15452 	 * again on the way to bpf_exit.
15453 	 * When looping the sl->state.branches will be > 0 and this state
15454 	 * will not be considered for equivalence until branches == 0.
15455 	 */
15456 	new_sl = kzalloc(sizeof(struct bpf_verifier_state_list), GFP_KERNEL);
15457 	if (!new_sl)
15458 		return -ENOMEM;
15459 	env->total_states++;
15460 	env->peak_states++;
15461 	env->prev_jmps_processed = env->jmps_processed;
15462 	env->prev_insn_processed = env->insn_processed;
15463 
15464 	/* forget precise markings we inherited, see __mark_chain_precision */
15465 	if (env->bpf_capable)
15466 		mark_all_scalars_imprecise(env, cur);
15467 
15468 	/* add new state to the head of linked list */
15469 	new = &new_sl->state;
15470 	err = copy_verifier_state(new, cur);
15471 	if (err) {
15472 		free_verifier_state(new, false);
15473 		kfree(new_sl);
15474 		return err;
15475 	}
15476 	new->insn_idx = insn_idx;
15477 	WARN_ONCE(new->branches != 1,
15478 		  "BUG is_state_visited:branches_to_explore=%d insn %d\n", new->branches, insn_idx);
15479 
15480 	cur->parent = new;
15481 	cur->first_insn_idx = insn_idx;
15482 	clear_jmp_history(cur);
15483 	new_sl->next = *explored_state(env, insn_idx);
15484 	*explored_state(env, insn_idx) = new_sl;
15485 	/* connect new state to parentage chain. Current frame needs all
15486 	 * registers connected. Only r6 - r9 of the callers are alive (pushed
15487 	 * to the stack implicitly by JITs) so in callers' frames connect just
15488 	 * r6 - r9 as an optimization. Callers will have r1 - r5 connected to
15489 	 * the state of the call instruction (with WRITTEN set), and r0 comes
15490 	 * from callee with its full parentage chain, anyway.
15491 	 */
15492 	/* clear write marks in current state: the writes we did are not writes
15493 	 * our child did, so they don't screen off its reads from us.
15494 	 * (There are no read marks in current state, because reads always mark
15495 	 * their parent and current state never has children yet.  Only
15496 	 * explored_states can get read marks.)
15497 	 */
15498 	for (j = 0; j <= cur->curframe; j++) {
15499 		for (i = j < cur->curframe ? BPF_REG_6 : 0; i < BPF_REG_FP; i++)
15500 			cur->frame[j]->regs[i].parent = &new->frame[j]->regs[i];
15501 		for (i = 0; i < BPF_REG_FP; i++)
15502 			cur->frame[j]->regs[i].live = REG_LIVE_NONE;
15503 	}
15504 
15505 	/* all stack frames are accessible from callee, clear them all */
15506 	for (j = 0; j <= cur->curframe; j++) {
15507 		struct bpf_func_state *frame = cur->frame[j];
15508 		struct bpf_func_state *newframe = new->frame[j];
15509 
15510 		for (i = 0; i < frame->allocated_stack / BPF_REG_SIZE; i++) {
15511 			frame->stack[i].spilled_ptr.live = REG_LIVE_NONE;
15512 			frame->stack[i].spilled_ptr.parent =
15513 						&newframe->stack[i].spilled_ptr;
15514 		}
15515 	}
15516 	return 0;
15517 }
15518 
15519 /* Return true if it's OK to have the same insn return a different type. */
15520 static bool reg_type_mismatch_ok(enum bpf_reg_type type)
15521 {
15522 	switch (base_type(type)) {
15523 	case PTR_TO_CTX:
15524 	case PTR_TO_SOCKET:
15525 	case PTR_TO_SOCK_COMMON:
15526 	case PTR_TO_TCP_SOCK:
15527 	case PTR_TO_XDP_SOCK:
15528 	case PTR_TO_BTF_ID:
15529 		return false;
15530 	default:
15531 		return true;
15532 	}
15533 }
15534 
15535 /* If an instruction was previously used with particular pointer types, then we
15536  * need to be careful to avoid cases such as the below, where it may be ok
15537  * for one branch accessing the pointer, but not ok for the other branch:
15538  *
15539  * R1 = sock_ptr
15540  * goto X;
15541  * ...
15542  * R1 = some_other_valid_ptr;
15543  * goto X;
15544  * ...
15545  * R2 = *(u32 *)(R1 + 0);
15546  */
15547 static bool reg_type_mismatch(enum bpf_reg_type src, enum bpf_reg_type prev)
15548 {
15549 	return src != prev && (!reg_type_mismatch_ok(src) ||
15550 			       !reg_type_mismatch_ok(prev));
15551 }
15552 
15553 static int save_aux_ptr_type(struct bpf_verifier_env *env, enum bpf_reg_type type,
15554 			     bool allow_trust_missmatch)
15555 {
15556 	enum bpf_reg_type *prev_type = &env->insn_aux_data[env->insn_idx].ptr_type;
15557 
15558 	if (*prev_type == NOT_INIT) {
15559 		/* Saw a valid insn
15560 		 * dst_reg = *(u32 *)(src_reg + off)
15561 		 * save type to validate intersecting paths
15562 		 */
15563 		*prev_type = type;
15564 	} else if (reg_type_mismatch(type, *prev_type)) {
15565 		/* Abuser program is trying to use the same insn
15566 		 * dst_reg = *(u32*) (src_reg + off)
15567 		 * with different pointer types:
15568 		 * src_reg == ctx in one branch and
15569 		 * src_reg == stack|map in some other branch.
15570 		 * Reject it.
15571 		 */
15572 		if (allow_trust_missmatch &&
15573 		    base_type(type) == PTR_TO_BTF_ID &&
15574 		    base_type(*prev_type) == PTR_TO_BTF_ID) {
15575 			/*
15576 			 * Have to support a use case when one path through
15577 			 * the program yields TRUSTED pointer while another
15578 			 * is UNTRUSTED. Fallback to UNTRUSTED to generate
15579 			 * BPF_PROBE_MEM.
15580 			 */
15581 			*prev_type = PTR_TO_BTF_ID | PTR_UNTRUSTED;
15582 		} else {
15583 			verbose(env, "same insn cannot be used with different pointers\n");
15584 			return -EINVAL;
15585 		}
15586 	}
15587 
15588 	return 0;
15589 }
15590 
15591 static int do_check(struct bpf_verifier_env *env)
15592 {
15593 	bool pop_log = !(env->log.level & BPF_LOG_LEVEL2);
15594 	struct bpf_verifier_state *state = env->cur_state;
15595 	struct bpf_insn *insns = env->prog->insnsi;
15596 	struct bpf_reg_state *regs;
15597 	int insn_cnt = env->prog->len;
15598 	bool do_print_state = false;
15599 	int prev_insn_idx = -1;
15600 
15601 	for (;;) {
15602 		struct bpf_insn *insn;
15603 		u8 class;
15604 		int err;
15605 
15606 		env->prev_insn_idx = prev_insn_idx;
15607 		if (env->insn_idx >= insn_cnt) {
15608 			verbose(env, "invalid insn idx %d insn_cnt %d\n",
15609 				env->insn_idx, insn_cnt);
15610 			return -EFAULT;
15611 		}
15612 
15613 		insn = &insns[env->insn_idx];
15614 		class = BPF_CLASS(insn->code);
15615 
15616 		if (++env->insn_processed > BPF_COMPLEXITY_LIMIT_INSNS) {
15617 			verbose(env,
15618 				"BPF program is too large. Processed %d insn\n",
15619 				env->insn_processed);
15620 			return -E2BIG;
15621 		}
15622 
15623 		state->last_insn_idx = env->prev_insn_idx;
15624 
15625 		if (is_prune_point(env, env->insn_idx)) {
15626 			err = is_state_visited(env, env->insn_idx);
15627 			if (err < 0)
15628 				return err;
15629 			if (err == 1) {
15630 				/* found equivalent state, can prune the search */
15631 				if (env->log.level & BPF_LOG_LEVEL) {
15632 					if (do_print_state)
15633 						verbose(env, "\nfrom %d to %d%s: safe\n",
15634 							env->prev_insn_idx, env->insn_idx,
15635 							env->cur_state->speculative ?
15636 							" (speculative execution)" : "");
15637 					else
15638 						verbose(env, "%d: safe\n", env->insn_idx);
15639 				}
15640 				goto process_bpf_exit;
15641 			}
15642 		}
15643 
15644 		if (is_jmp_point(env, env->insn_idx)) {
15645 			err = push_jmp_history(env, state);
15646 			if (err)
15647 				return err;
15648 		}
15649 
15650 		if (signal_pending(current))
15651 			return -EAGAIN;
15652 
15653 		if (need_resched())
15654 			cond_resched();
15655 
15656 		if (env->log.level & BPF_LOG_LEVEL2 && do_print_state) {
15657 			verbose(env, "\nfrom %d to %d%s:",
15658 				env->prev_insn_idx, env->insn_idx,
15659 				env->cur_state->speculative ?
15660 				" (speculative execution)" : "");
15661 			print_verifier_state(env, state->frame[state->curframe], true);
15662 			do_print_state = false;
15663 		}
15664 
15665 		if (env->log.level & BPF_LOG_LEVEL) {
15666 			const struct bpf_insn_cbs cbs = {
15667 				.cb_call	= disasm_kfunc_name,
15668 				.cb_print	= verbose,
15669 				.private_data	= env,
15670 			};
15671 
15672 			if (verifier_state_scratched(env))
15673 				print_insn_state(env, state->frame[state->curframe]);
15674 
15675 			verbose_linfo(env, env->insn_idx, "; ");
15676 			env->prev_log_pos = env->log.end_pos;
15677 			verbose(env, "%d: ", env->insn_idx);
15678 			print_bpf_insn(&cbs, insn, env->allow_ptr_leaks);
15679 			env->prev_insn_print_pos = env->log.end_pos - env->prev_log_pos;
15680 			env->prev_log_pos = env->log.end_pos;
15681 		}
15682 
15683 		if (bpf_prog_is_offloaded(env->prog->aux)) {
15684 			err = bpf_prog_offload_verify_insn(env, env->insn_idx,
15685 							   env->prev_insn_idx);
15686 			if (err)
15687 				return err;
15688 		}
15689 
15690 		regs = cur_regs(env);
15691 		sanitize_mark_insn_seen(env);
15692 		prev_insn_idx = env->insn_idx;
15693 
15694 		if (class == BPF_ALU || class == BPF_ALU64) {
15695 			err = check_alu_op(env, insn);
15696 			if (err)
15697 				return err;
15698 
15699 		} else if (class == BPF_LDX) {
15700 			enum bpf_reg_type src_reg_type;
15701 
15702 			/* check for reserved fields is already done */
15703 
15704 			/* check src operand */
15705 			err = check_reg_arg(env, insn->src_reg, SRC_OP);
15706 			if (err)
15707 				return err;
15708 
15709 			err = check_reg_arg(env, insn->dst_reg, DST_OP_NO_MARK);
15710 			if (err)
15711 				return err;
15712 
15713 			src_reg_type = regs[insn->src_reg].type;
15714 
15715 			/* check that memory (src_reg + off) is readable,
15716 			 * the state of dst_reg will be updated by this func
15717 			 */
15718 			err = check_mem_access(env, env->insn_idx, insn->src_reg,
15719 					       insn->off, BPF_SIZE(insn->code),
15720 					       BPF_READ, insn->dst_reg, false);
15721 			if (err)
15722 				return err;
15723 
15724 			err = save_aux_ptr_type(env, src_reg_type, true);
15725 			if (err)
15726 				return err;
15727 		} else if (class == BPF_STX) {
15728 			enum bpf_reg_type dst_reg_type;
15729 
15730 			if (BPF_MODE(insn->code) == BPF_ATOMIC) {
15731 				err = check_atomic(env, env->insn_idx, insn);
15732 				if (err)
15733 					return err;
15734 				env->insn_idx++;
15735 				continue;
15736 			}
15737 
15738 			if (BPF_MODE(insn->code) != BPF_MEM || insn->imm != 0) {
15739 				verbose(env, "BPF_STX uses reserved fields\n");
15740 				return -EINVAL;
15741 			}
15742 
15743 			/* check src1 operand */
15744 			err = check_reg_arg(env, insn->src_reg, SRC_OP);
15745 			if (err)
15746 				return err;
15747 			/* check src2 operand */
15748 			err = check_reg_arg(env, insn->dst_reg, SRC_OP);
15749 			if (err)
15750 				return err;
15751 
15752 			dst_reg_type = regs[insn->dst_reg].type;
15753 
15754 			/* check that memory (dst_reg + off) is writeable */
15755 			err = check_mem_access(env, env->insn_idx, insn->dst_reg,
15756 					       insn->off, BPF_SIZE(insn->code),
15757 					       BPF_WRITE, insn->src_reg, false);
15758 			if (err)
15759 				return err;
15760 
15761 			err = save_aux_ptr_type(env, dst_reg_type, false);
15762 			if (err)
15763 				return err;
15764 		} else if (class == BPF_ST) {
15765 			enum bpf_reg_type dst_reg_type;
15766 
15767 			if (BPF_MODE(insn->code) != BPF_MEM ||
15768 			    insn->src_reg != BPF_REG_0) {
15769 				verbose(env, "BPF_ST uses reserved fields\n");
15770 				return -EINVAL;
15771 			}
15772 			/* check src operand */
15773 			err = check_reg_arg(env, insn->dst_reg, SRC_OP);
15774 			if (err)
15775 				return err;
15776 
15777 			dst_reg_type = regs[insn->dst_reg].type;
15778 
15779 			/* check that memory (dst_reg + off) is writeable */
15780 			err = check_mem_access(env, env->insn_idx, insn->dst_reg,
15781 					       insn->off, BPF_SIZE(insn->code),
15782 					       BPF_WRITE, -1, false);
15783 			if (err)
15784 				return err;
15785 
15786 			err = save_aux_ptr_type(env, dst_reg_type, false);
15787 			if (err)
15788 				return err;
15789 		} else if (class == BPF_JMP || class == BPF_JMP32) {
15790 			u8 opcode = BPF_OP(insn->code);
15791 
15792 			env->jmps_processed++;
15793 			if (opcode == BPF_CALL) {
15794 				if (BPF_SRC(insn->code) != BPF_K ||
15795 				    (insn->src_reg != BPF_PSEUDO_KFUNC_CALL
15796 				     && insn->off != 0) ||
15797 				    (insn->src_reg != BPF_REG_0 &&
15798 				     insn->src_reg != BPF_PSEUDO_CALL &&
15799 				     insn->src_reg != BPF_PSEUDO_KFUNC_CALL) ||
15800 				    insn->dst_reg != BPF_REG_0 ||
15801 				    class == BPF_JMP32) {
15802 					verbose(env, "BPF_CALL uses reserved fields\n");
15803 					return -EINVAL;
15804 				}
15805 
15806 				if (env->cur_state->active_lock.ptr) {
15807 					if ((insn->src_reg == BPF_REG_0 && insn->imm != BPF_FUNC_spin_unlock) ||
15808 					    (insn->src_reg == BPF_PSEUDO_CALL) ||
15809 					    (insn->src_reg == BPF_PSEUDO_KFUNC_CALL &&
15810 					     (insn->off != 0 || !is_bpf_graph_api_kfunc(insn->imm)))) {
15811 						verbose(env, "function calls are not allowed while holding a lock\n");
15812 						return -EINVAL;
15813 					}
15814 				}
15815 				if (insn->src_reg == BPF_PSEUDO_CALL)
15816 					err = check_func_call(env, insn, &env->insn_idx);
15817 				else if (insn->src_reg == BPF_PSEUDO_KFUNC_CALL)
15818 					err = check_kfunc_call(env, insn, &env->insn_idx);
15819 				else
15820 					err = check_helper_call(env, insn, &env->insn_idx);
15821 				if (err)
15822 					return err;
15823 
15824 				mark_reg_scratched(env, BPF_REG_0);
15825 			} else if (opcode == BPF_JA) {
15826 				if (BPF_SRC(insn->code) != BPF_K ||
15827 				    insn->imm != 0 ||
15828 				    insn->src_reg != BPF_REG_0 ||
15829 				    insn->dst_reg != BPF_REG_0 ||
15830 				    class == BPF_JMP32) {
15831 					verbose(env, "BPF_JA uses reserved fields\n");
15832 					return -EINVAL;
15833 				}
15834 
15835 				env->insn_idx += insn->off + 1;
15836 				continue;
15837 
15838 			} else if (opcode == BPF_EXIT) {
15839 				if (BPF_SRC(insn->code) != BPF_K ||
15840 				    insn->imm != 0 ||
15841 				    insn->src_reg != BPF_REG_0 ||
15842 				    insn->dst_reg != BPF_REG_0 ||
15843 				    class == BPF_JMP32) {
15844 					verbose(env, "BPF_EXIT uses reserved fields\n");
15845 					return -EINVAL;
15846 				}
15847 
15848 				if (env->cur_state->active_lock.ptr &&
15849 				    !in_rbtree_lock_required_cb(env)) {
15850 					verbose(env, "bpf_spin_unlock is missing\n");
15851 					return -EINVAL;
15852 				}
15853 
15854 				if (env->cur_state->active_rcu_lock) {
15855 					verbose(env, "bpf_rcu_read_unlock is missing\n");
15856 					return -EINVAL;
15857 				}
15858 
15859 				/* We must do check_reference_leak here before
15860 				 * prepare_func_exit to handle the case when
15861 				 * state->curframe > 0, it may be a callback
15862 				 * function, for which reference_state must
15863 				 * match caller reference state when it exits.
15864 				 */
15865 				err = check_reference_leak(env);
15866 				if (err)
15867 					return err;
15868 
15869 				if (state->curframe) {
15870 					/* exit from nested function */
15871 					err = prepare_func_exit(env, &env->insn_idx);
15872 					if (err)
15873 						return err;
15874 					do_print_state = true;
15875 					continue;
15876 				}
15877 
15878 				err = check_return_code(env);
15879 				if (err)
15880 					return err;
15881 process_bpf_exit:
15882 				mark_verifier_state_scratched(env);
15883 				update_branch_counts(env, env->cur_state);
15884 				err = pop_stack(env, &prev_insn_idx,
15885 						&env->insn_idx, pop_log);
15886 				if (err < 0) {
15887 					if (err != -ENOENT)
15888 						return err;
15889 					break;
15890 				} else {
15891 					do_print_state = true;
15892 					continue;
15893 				}
15894 			} else {
15895 				err = check_cond_jmp_op(env, insn, &env->insn_idx);
15896 				if (err)
15897 					return err;
15898 			}
15899 		} else if (class == BPF_LD) {
15900 			u8 mode = BPF_MODE(insn->code);
15901 
15902 			if (mode == BPF_ABS || mode == BPF_IND) {
15903 				err = check_ld_abs(env, insn);
15904 				if (err)
15905 					return err;
15906 
15907 			} else if (mode == BPF_IMM) {
15908 				err = check_ld_imm(env, insn);
15909 				if (err)
15910 					return err;
15911 
15912 				env->insn_idx++;
15913 				sanitize_mark_insn_seen(env);
15914 			} else {
15915 				verbose(env, "invalid BPF_LD mode\n");
15916 				return -EINVAL;
15917 			}
15918 		} else {
15919 			verbose(env, "unknown insn class %d\n", class);
15920 			return -EINVAL;
15921 		}
15922 
15923 		env->insn_idx++;
15924 	}
15925 
15926 	return 0;
15927 }
15928 
15929 static int find_btf_percpu_datasec(struct btf *btf)
15930 {
15931 	const struct btf_type *t;
15932 	const char *tname;
15933 	int i, n;
15934 
15935 	/*
15936 	 * Both vmlinux and module each have their own ".data..percpu"
15937 	 * DATASECs in BTF. So for module's case, we need to skip vmlinux BTF
15938 	 * types to look at only module's own BTF types.
15939 	 */
15940 	n = btf_nr_types(btf);
15941 	if (btf_is_module(btf))
15942 		i = btf_nr_types(btf_vmlinux);
15943 	else
15944 		i = 1;
15945 
15946 	for(; i < n; i++) {
15947 		t = btf_type_by_id(btf, i);
15948 		if (BTF_INFO_KIND(t->info) != BTF_KIND_DATASEC)
15949 			continue;
15950 
15951 		tname = btf_name_by_offset(btf, t->name_off);
15952 		if (!strcmp(tname, ".data..percpu"))
15953 			return i;
15954 	}
15955 
15956 	return -ENOENT;
15957 }
15958 
15959 /* replace pseudo btf_id with kernel symbol address */
15960 static int check_pseudo_btf_id(struct bpf_verifier_env *env,
15961 			       struct bpf_insn *insn,
15962 			       struct bpf_insn_aux_data *aux)
15963 {
15964 	const struct btf_var_secinfo *vsi;
15965 	const struct btf_type *datasec;
15966 	struct btf_mod_pair *btf_mod;
15967 	const struct btf_type *t;
15968 	const char *sym_name;
15969 	bool percpu = false;
15970 	u32 type, id = insn->imm;
15971 	struct btf *btf;
15972 	s32 datasec_id;
15973 	u64 addr;
15974 	int i, btf_fd, err;
15975 
15976 	btf_fd = insn[1].imm;
15977 	if (btf_fd) {
15978 		btf = btf_get_by_fd(btf_fd);
15979 		if (IS_ERR(btf)) {
15980 			verbose(env, "invalid module BTF object FD specified.\n");
15981 			return -EINVAL;
15982 		}
15983 	} else {
15984 		if (!btf_vmlinux) {
15985 			verbose(env, "kernel is missing BTF, make sure CONFIG_DEBUG_INFO_BTF=y is specified in Kconfig.\n");
15986 			return -EINVAL;
15987 		}
15988 		btf = btf_vmlinux;
15989 		btf_get(btf);
15990 	}
15991 
15992 	t = btf_type_by_id(btf, id);
15993 	if (!t) {
15994 		verbose(env, "ldimm64 insn specifies invalid btf_id %d.\n", id);
15995 		err = -ENOENT;
15996 		goto err_put;
15997 	}
15998 
15999 	if (!btf_type_is_var(t) && !btf_type_is_func(t)) {
16000 		verbose(env, "pseudo btf_id %d in ldimm64 isn't KIND_VAR or KIND_FUNC\n", id);
16001 		err = -EINVAL;
16002 		goto err_put;
16003 	}
16004 
16005 	sym_name = btf_name_by_offset(btf, t->name_off);
16006 	addr = kallsyms_lookup_name(sym_name);
16007 	if (!addr) {
16008 		verbose(env, "ldimm64 failed to find the address for kernel symbol '%s'.\n",
16009 			sym_name);
16010 		err = -ENOENT;
16011 		goto err_put;
16012 	}
16013 	insn[0].imm = (u32)addr;
16014 	insn[1].imm = addr >> 32;
16015 
16016 	if (btf_type_is_func(t)) {
16017 		aux->btf_var.reg_type = PTR_TO_MEM | MEM_RDONLY;
16018 		aux->btf_var.mem_size = 0;
16019 		goto check_btf;
16020 	}
16021 
16022 	datasec_id = find_btf_percpu_datasec(btf);
16023 	if (datasec_id > 0) {
16024 		datasec = btf_type_by_id(btf, datasec_id);
16025 		for_each_vsi(i, datasec, vsi) {
16026 			if (vsi->type == id) {
16027 				percpu = true;
16028 				break;
16029 			}
16030 		}
16031 	}
16032 
16033 	type = t->type;
16034 	t = btf_type_skip_modifiers(btf, type, NULL);
16035 	if (percpu) {
16036 		aux->btf_var.reg_type = PTR_TO_BTF_ID | MEM_PERCPU;
16037 		aux->btf_var.btf = btf;
16038 		aux->btf_var.btf_id = type;
16039 	} else if (!btf_type_is_struct(t)) {
16040 		const struct btf_type *ret;
16041 		const char *tname;
16042 		u32 tsize;
16043 
16044 		/* resolve the type size of ksym. */
16045 		ret = btf_resolve_size(btf, t, &tsize);
16046 		if (IS_ERR(ret)) {
16047 			tname = btf_name_by_offset(btf, t->name_off);
16048 			verbose(env, "ldimm64 unable to resolve the size of type '%s': %ld\n",
16049 				tname, PTR_ERR(ret));
16050 			err = -EINVAL;
16051 			goto err_put;
16052 		}
16053 		aux->btf_var.reg_type = PTR_TO_MEM | MEM_RDONLY;
16054 		aux->btf_var.mem_size = tsize;
16055 	} else {
16056 		aux->btf_var.reg_type = PTR_TO_BTF_ID;
16057 		aux->btf_var.btf = btf;
16058 		aux->btf_var.btf_id = type;
16059 	}
16060 check_btf:
16061 	/* check whether we recorded this BTF (and maybe module) already */
16062 	for (i = 0; i < env->used_btf_cnt; i++) {
16063 		if (env->used_btfs[i].btf == btf) {
16064 			btf_put(btf);
16065 			return 0;
16066 		}
16067 	}
16068 
16069 	if (env->used_btf_cnt >= MAX_USED_BTFS) {
16070 		err = -E2BIG;
16071 		goto err_put;
16072 	}
16073 
16074 	btf_mod = &env->used_btfs[env->used_btf_cnt];
16075 	btf_mod->btf = btf;
16076 	btf_mod->module = NULL;
16077 
16078 	/* if we reference variables from kernel module, bump its refcount */
16079 	if (btf_is_module(btf)) {
16080 		btf_mod->module = btf_try_get_module(btf);
16081 		if (!btf_mod->module) {
16082 			err = -ENXIO;
16083 			goto err_put;
16084 		}
16085 	}
16086 
16087 	env->used_btf_cnt++;
16088 
16089 	return 0;
16090 err_put:
16091 	btf_put(btf);
16092 	return err;
16093 }
16094 
16095 static bool is_tracing_prog_type(enum bpf_prog_type type)
16096 {
16097 	switch (type) {
16098 	case BPF_PROG_TYPE_KPROBE:
16099 	case BPF_PROG_TYPE_TRACEPOINT:
16100 	case BPF_PROG_TYPE_PERF_EVENT:
16101 	case BPF_PROG_TYPE_RAW_TRACEPOINT:
16102 	case BPF_PROG_TYPE_RAW_TRACEPOINT_WRITABLE:
16103 		return true;
16104 	default:
16105 		return false;
16106 	}
16107 }
16108 
16109 static int check_map_prog_compatibility(struct bpf_verifier_env *env,
16110 					struct bpf_map *map,
16111 					struct bpf_prog *prog)
16112 
16113 {
16114 	enum bpf_prog_type prog_type = resolve_prog_type(prog);
16115 
16116 	if (btf_record_has_field(map->record, BPF_LIST_HEAD) ||
16117 	    btf_record_has_field(map->record, BPF_RB_ROOT)) {
16118 		if (is_tracing_prog_type(prog_type)) {
16119 			verbose(env, "tracing progs cannot use bpf_{list_head,rb_root} yet\n");
16120 			return -EINVAL;
16121 		}
16122 	}
16123 
16124 	if (btf_record_has_field(map->record, BPF_SPIN_LOCK)) {
16125 		if (prog_type == BPF_PROG_TYPE_SOCKET_FILTER) {
16126 			verbose(env, "socket filter progs cannot use bpf_spin_lock yet\n");
16127 			return -EINVAL;
16128 		}
16129 
16130 		if (is_tracing_prog_type(prog_type)) {
16131 			verbose(env, "tracing progs cannot use bpf_spin_lock yet\n");
16132 			return -EINVAL;
16133 		}
16134 
16135 		if (prog->aux->sleepable) {
16136 			verbose(env, "sleepable progs cannot use bpf_spin_lock yet\n");
16137 			return -EINVAL;
16138 		}
16139 	}
16140 
16141 	if (btf_record_has_field(map->record, BPF_TIMER)) {
16142 		if (is_tracing_prog_type(prog_type)) {
16143 			verbose(env, "tracing progs cannot use bpf_timer yet\n");
16144 			return -EINVAL;
16145 		}
16146 	}
16147 
16148 	if ((bpf_prog_is_offloaded(prog->aux) || bpf_map_is_offloaded(map)) &&
16149 	    !bpf_offload_prog_map_match(prog, map)) {
16150 		verbose(env, "offload device mismatch between prog and map\n");
16151 		return -EINVAL;
16152 	}
16153 
16154 	if (map->map_type == BPF_MAP_TYPE_STRUCT_OPS) {
16155 		verbose(env, "bpf_struct_ops map cannot be used in prog\n");
16156 		return -EINVAL;
16157 	}
16158 
16159 	if (prog->aux->sleepable)
16160 		switch (map->map_type) {
16161 		case BPF_MAP_TYPE_HASH:
16162 		case BPF_MAP_TYPE_LRU_HASH:
16163 		case BPF_MAP_TYPE_ARRAY:
16164 		case BPF_MAP_TYPE_PERCPU_HASH:
16165 		case BPF_MAP_TYPE_PERCPU_ARRAY:
16166 		case BPF_MAP_TYPE_LRU_PERCPU_HASH:
16167 		case BPF_MAP_TYPE_ARRAY_OF_MAPS:
16168 		case BPF_MAP_TYPE_HASH_OF_MAPS:
16169 		case BPF_MAP_TYPE_RINGBUF:
16170 		case BPF_MAP_TYPE_USER_RINGBUF:
16171 		case BPF_MAP_TYPE_INODE_STORAGE:
16172 		case BPF_MAP_TYPE_SK_STORAGE:
16173 		case BPF_MAP_TYPE_TASK_STORAGE:
16174 		case BPF_MAP_TYPE_CGRP_STORAGE:
16175 			break;
16176 		default:
16177 			verbose(env,
16178 				"Sleepable programs can only use array, hash, ringbuf and local storage maps\n");
16179 			return -EINVAL;
16180 		}
16181 
16182 	return 0;
16183 }
16184 
16185 static bool bpf_map_is_cgroup_storage(struct bpf_map *map)
16186 {
16187 	return (map->map_type == BPF_MAP_TYPE_CGROUP_STORAGE ||
16188 		map->map_type == BPF_MAP_TYPE_PERCPU_CGROUP_STORAGE);
16189 }
16190 
16191 /* find and rewrite pseudo imm in ld_imm64 instructions:
16192  *
16193  * 1. if it accesses map FD, replace it with actual map pointer.
16194  * 2. if it accesses btf_id of a VAR, replace it with pointer to the var.
16195  *
16196  * NOTE: btf_vmlinux is required for converting pseudo btf_id.
16197  */
16198 static int resolve_pseudo_ldimm64(struct bpf_verifier_env *env)
16199 {
16200 	struct bpf_insn *insn = env->prog->insnsi;
16201 	int insn_cnt = env->prog->len;
16202 	int i, j, err;
16203 
16204 	err = bpf_prog_calc_tag(env->prog);
16205 	if (err)
16206 		return err;
16207 
16208 	for (i = 0; i < insn_cnt; i++, insn++) {
16209 		if (BPF_CLASS(insn->code) == BPF_LDX &&
16210 		    (BPF_MODE(insn->code) != BPF_MEM || insn->imm != 0)) {
16211 			verbose(env, "BPF_LDX uses reserved fields\n");
16212 			return -EINVAL;
16213 		}
16214 
16215 		if (insn[0].code == (BPF_LD | BPF_IMM | BPF_DW)) {
16216 			struct bpf_insn_aux_data *aux;
16217 			struct bpf_map *map;
16218 			struct fd f;
16219 			u64 addr;
16220 			u32 fd;
16221 
16222 			if (i == insn_cnt - 1 || insn[1].code != 0 ||
16223 			    insn[1].dst_reg != 0 || insn[1].src_reg != 0 ||
16224 			    insn[1].off != 0) {
16225 				verbose(env, "invalid bpf_ld_imm64 insn\n");
16226 				return -EINVAL;
16227 			}
16228 
16229 			if (insn[0].src_reg == 0)
16230 				/* valid generic load 64-bit imm */
16231 				goto next_insn;
16232 
16233 			if (insn[0].src_reg == BPF_PSEUDO_BTF_ID) {
16234 				aux = &env->insn_aux_data[i];
16235 				err = check_pseudo_btf_id(env, insn, aux);
16236 				if (err)
16237 					return err;
16238 				goto next_insn;
16239 			}
16240 
16241 			if (insn[0].src_reg == BPF_PSEUDO_FUNC) {
16242 				aux = &env->insn_aux_data[i];
16243 				aux->ptr_type = PTR_TO_FUNC;
16244 				goto next_insn;
16245 			}
16246 
16247 			/* In final convert_pseudo_ld_imm64() step, this is
16248 			 * converted into regular 64-bit imm load insn.
16249 			 */
16250 			switch (insn[0].src_reg) {
16251 			case BPF_PSEUDO_MAP_VALUE:
16252 			case BPF_PSEUDO_MAP_IDX_VALUE:
16253 				break;
16254 			case BPF_PSEUDO_MAP_FD:
16255 			case BPF_PSEUDO_MAP_IDX:
16256 				if (insn[1].imm == 0)
16257 					break;
16258 				fallthrough;
16259 			default:
16260 				verbose(env, "unrecognized bpf_ld_imm64 insn\n");
16261 				return -EINVAL;
16262 			}
16263 
16264 			switch (insn[0].src_reg) {
16265 			case BPF_PSEUDO_MAP_IDX_VALUE:
16266 			case BPF_PSEUDO_MAP_IDX:
16267 				if (bpfptr_is_null(env->fd_array)) {
16268 					verbose(env, "fd_idx without fd_array is invalid\n");
16269 					return -EPROTO;
16270 				}
16271 				if (copy_from_bpfptr_offset(&fd, env->fd_array,
16272 							    insn[0].imm * sizeof(fd),
16273 							    sizeof(fd)))
16274 					return -EFAULT;
16275 				break;
16276 			default:
16277 				fd = insn[0].imm;
16278 				break;
16279 			}
16280 
16281 			f = fdget(fd);
16282 			map = __bpf_map_get(f);
16283 			if (IS_ERR(map)) {
16284 				verbose(env, "fd %d is not pointing to valid bpf_map\n",
16285 					insn[0].imm);
16286 				return PTR_ERR(map);
16287 			}
16288 
16289 			err = check_map_prog_compatibility(env, map, env->prog);
16290 			if (err) {
16291 				fdput(f);
16292 				return err;
16293 			}
16294 
16295 			aux = &env->insn_aux_data[i];
16296 			if (insn[0].src_reg == BPF_PSEUDO_MAP_FD ||
16297 			    insn[0].src_reg == BPF_PSEUDO_MAP_IDX) {
16298 				addr = (unsigned long)map;
16299 			} else {
16300 				u32 off = insn[1].imm;
16301 
16302 				if (off >= BPF_MAX_VAR_OFF) {
16303 					verbose(env, "direct value offset of %u is not allowed\n", off);
16304 					fdput(f);
16305 					return -EINVAL;
16306 				}
16307 
16308 				if (!map->ops->map_direct_value_addr) {
16309 					verbose(env, "no direct value access support for this map type\n");
16310 					fdput(f);
16311 					return -EINVAL;
16312 				}
16313 
16314 				err = map->ops->map_direct_value_addr(map, &addr, off);
16315 				if (err) {
16316 					verbose(env, "invalid access to map value pointer, value_size=%u off=%u\n",
16317 						map->value_size, off);
16318 					fdput(f);
16319 					return err;
16320 				}
16321 
16322 				aux->map_off = off;
16323 				addr += off;
16324 			}
16325 
16326 			insn[0].imm = (u32)addr;
16327 			insn[1].imm = addr >> 32;
16328 
16329 			/* check whether we recorded this map already */
16330 			for (j = 0; j < env->used_map_cnt; j++) {
16331 				if (env->used_maps[j] == map) {
16332 					aux->map_index = j;
16333 					fdput(f);
16334 					goto next_insn;
16335 				}
16336 			}
16337 
16338 			if (env->used_map_cnt >= MAX_USED_MAPS) {
16339 				fdput(f);
16340 				return -E2BIG;
16341 			}
16342 
16343 			/* hold the map. If the program is rejected by verifier,
16344 			 * the map will be released by release_maps() or it
16345 			 * will be used by the valid program until it's unloaded
16346 			 * and all maps are released in free_used_maps()
16347 			 */
16348 			bpf_map_inc(map);
16349 
16350 			aux->map_index = env->used_map_cnt;
16351 			env->used_maps[env->used_map_cnt++] = map;
16352 
16353 			if (bpf_map_is_cgroup_storage(map) &&
16354 			    bpf_cgroup_storage_assign(env->prog->aux, map)) {
16355 				verbose(env, "only one cgroup storage of each type is allowed\n");
16356 				fdput(f);
16357 				return -EBUSY;
16358 			}
16359 
16360 			fdput(f);
16361 next_insn:
16362 			insn++;
16363 			i++;
16364 			continue;
16365 		}
16366 
16367 		/* Basic sanity check before we invest more work here. */
16368 		if (!bpf_opcode_in_insntable(insn->code)) {
16369 			verbose(env, "unknown opcode %02x\n", insn->code);
16370 			return -EINVAL;
16371 		}
16372 	}
16373 
16374 	/* now all pseudo BPF_LD_IMM64 instructions load valid
16375 	 * 'struct bpf_map *' into a register instead of user map_fd.
16376 	 * These pointers will be used later by verifier to validate map access.
16377 	 */
16378 	return 0;
16379 }
16380 
16381 /* drop refcnt of maps used by the rejected program */
16382 static void release_maps(struct bpf_verifier_env *env)
16383 {
16384 	__bpf_free_used_maps(env->prog->aux, env->used_maps,
16385 			     env->used_map_cnt);
16386 }
16387 
16388 /* drop refcnt of maps used by the rejected program */
16389 static void release_btfs(struct bpf_verifier_env *env)
16390 {
16391 	__bpf_free_used_btfs(env->prog->aux, env->used_btfs,
16392 			     env->used_btf_cnt);
16393 }
16394 
16395 /* convert pseudo BPF_LD_IMM64 into generic BPF_LD_IMM64 */
16396 static void convert_pseudo_ld_imm64(struct bpf_verifier_env *env)
16397 {
16398 	struct bpf_insn *insn = env->prog->insnsi;
16399 	int insn_cnt = env->prog->len;
16400 	int i;
16401 
16402 	for (i = 0; i < insn_cnt; i++, insn++) {
16403 		if (insn->code != (BPF_LD | BPF_IMM | BPF_DW))
16404 			continue;
16405 		if (insn->src_reg == BPF_PSEUDO_FUNC)
16406 			continue;
16407 		insn->src_reg = 0;
16408 	}
16409 }
16410 
16411 /* single env->prog->insni[off] instruction was replaced with the range
16412  * insni[off, off + cnt).  Adjust corresponding insn_aux_data by copying
16413  * [0, off) and [off, end) to new locations, so the patched range stays zero
16414  */
16415 static void adjust_insn_aux_data(struct bpf_verifier_env *env,
16416 				 struct bpf_insn_aux_data *new_data,
16417 				 struct bpf_prog *new_prog, u32 off, u32 cnt)
16418 {
16419 	struct bpf_insn_aux_data *old_data = env->insn_aux_data;
16420 	struct bpf_insn *insn = new_prog->insnsi;
16421 	u32 old_seen = old_data[off].seen;
16422 	u32 prog_len;
16423 	int i;
16424 
16425 	/* aux info at OFF always needs adjustment, no matter fast path
16426 	 * (cnt == 1) is taken or not. There is no guarantee INSN at OFF is the
16427 	 * original insn at old prog.
16428 	 */
16429 	old_data[off].zext_dst = insn_has_def32(env, insn + off + cnt - 1);
16430 
16431 	if (cnt == 1)
16432 		return;
16433 	prog_len = new_prog->len;
16434 
16435 	memcpy(new_data, old_data, sizeof(struct bpf_insn_aux_data) * off);
16436 	memcpy(new_data + off + cnt - 1, old_data + off,
16437 	       sizeof(struct bpf_insn_aux_data) * (prog_len - off - cnt + 1));
16438 	for (i = off; i < off + cnt - 1; i++) {
16439 		/* Expand insni[off]'s seen count to the patched range. */
16440 		new_data[i].seen = old_seen;
16441 		new_data[i].zext_dst = insn_has_def32(env, insn + i);
16442 	}
16443 	env->insn_aux_data = new_data;
16444 	vfree(old_data);
16445 }
16446 
16447 static void adjust_subprog_starts(struct bpf_verifier_env *env, u32 off, u32 len)
16448 {
16449 	int i;
16450 
16451 	if (len == 1)
16452 		return;
16453 	/* NOTE: fake 'exit' subprog should be updated as well. */
16454 	for (i = 0; i <= env->subprog_cnt; i++) {
16455 		if (env->subprog_info[i].start <= off)
16456 			continue;
16457 		env->subprog_info[i].start += len - 1;
16458 	}
16459 }
16460 
16461 static void adjust_poke_descs(struct bpf_prog *prog, u32 off, u32 len)
16462 {
16463 	struct bpf_jit_poke_descriptor *tab = prog->aux->poke_tab;
16464 	int i, sz = prog->aux->size_poke_tab;
16465 	struct bpf_jit_poke_descriptor *desc;
16466 
16467 	for (i = 0; i < sz; i++) {
16468 		desc = &tab[i];
16469 		if (desc->insn_idx <= off)
16470 			continue;
16471 		desc->insn_idx += len - 1;
16472 	}
16473 }
16474 
16475 static struct bpf_prog *bpf_patch_insn_data(struct bpf_verifier_env *env, u32 off,
16476 					    const struct bpf_insn *patch, u32 len)
16477 {
16478 	struct bpf_prog *new_prog;
16479 	struct bpf_insn_aux_data *new_data = NULL;
16480 
16481 	if (len > 1) {
16482 		new_data = vzalloc(array_size(env->prog->len + len - 1,
16483 					      sizeof(struct bpf_insn_aux_data)));
16484 		if (!new_data)
16485 			return NULL;
16486 	}
16487 
16488 	new_prog = bpf_patch_insn_single(env->prog, off, patch, len);
16489 	if (IS_ERR(new_prog)) {
16490 		if (PTR_ERR(new_prog) == -ERANGE)
16491 			verbose(env,
16492 				"insn %d cannot be patched due to 16-bit range\n",
16493 				env->insn_aux_data[off].orig_idx);
16494 		vfree(new_data);
16495 		return NULL;
16496 	}
16497 	adjust_insn_aux_data(env, new_data, new_prog, off, len);
16498 	adjust_subprog_starts(env, off, len);
16499 	adjust_poke_descs(new_prog, off, len);
16500 	return new_prog;
16501 }
16502 
16503 static int adjust_subprog_starts_after_remove(struct bpf_verifier_env *env,
16504 					      u32 off, u32 cnt)
16505 {
16506 	int i, j;
16507 
16508 	/* find first prog starting at or after off (first to remove) */
16509 	for (i = 0; i < env->subprog_cnt; i++)
16510 		if (env->subprog_info[i].start >= off)
16511 			break;
16512 	/* find first prog starting at or after off + cnt (first to stay) */
16513 	for (j = i; j < env->subprog_cnt; j++)
16514 		if (env->subprog_info[j].start >= off + cnt)
16515 			break;
16516 	/* if j doesn't start exactly at off + cnt, we are just removing
16517 	 * the front of previous prog
16518 	 */
16519 	if (env->subprog_info[j].start != off + cnt)
16520 		j--;
16521 
16522 	if (j > i) {
16523 		struct bpf_prog_aux *aux = env->prog->aux;
16524 		int move;
16525 
16526 		/* move fake 'exit' subprog as well */
16527 		move = env->subprog_cnt + 1 - j;
16528 
16529 		memmove(env->subprog_info + i,
16530 			env->subprog_info + j,
16531 			sizeof(*env->subprog_info) * move);
16532 		env->subprog_cnt -= j - i;
16533 
16534 		/* remove func_info */
16535 		if (aux->func_info) {
16536 			move = aux->func_info_cnt - j;
16537 
16538 			memmove(aux->func_info + i,
16539 				aux->func_info + j,
16540 				sizeof(*aux->func_info) * move);
16541 			aux->func_info_cnt -= j - i;
16542 			/* func_info->insn_off is set after all code rewrites,
16543 			 * in adjust_btf_func() - no need to adjust
16544 			 */
16545 		}
16546 	} else {
16547 		/* convert i from "first prog to remove" to "first to adjust" */
16548 		if (env->subprog_info[i].start == off)
16549 			i++;
16550 	}
16551 
16552 	/* update fake 'exit' subprog as well */
16553 	for (; i <= env->subprog_cnt; i++)
16554 		env->subprog_info[i].start -= cnt;
16555 
16556 	return 0;
16557 }
16558 
16559 static int bpf_adj_linfo_after_remove(struct bpf_verifier_env *env, u32 off,
16560 				      u32 cnt)
16561 {
16562 	struct bpf_prog *prog = env->prog;
16563 	u32 i, l_off, l_cnt, nr_linfo;
16564 	struct bpf_line_info *linfo;
16565 
16566 	nr_linfo = prog->aux->nr_linfo;
16567 	if (!nr_linfo)
16568 		return 0;
16569 
16570 	linfo = prog->aux->linfo;
16571 
16572 	/* find first line info to remove, count lines to be removed */
16573 	for (i = 0; i < nr_linfo; i++)
16574 		if (linfo[i].insn_off >= off)
16575 			break;
16576 
16577 	l_off = i;
16578 	l_cnt = 0;
16579 	for (; i < nr_linfo; i++)
16580 		if (linfo[i].insn_off < off + cnt)
16581 			l_cnt++;
16582 		else
16583 			break;
16584 
16585 	/* First live insn doesn't match first live linfo, it needs to "inherit"
16586 	 * last removed linfo.  prog is already modified, so prog->len == off
16587 	 * means no live instructions after (tail of the program was removed).
16588 	 */
16589 	if (prog->len != off && l_cnt &&
16590 	    (i == nr_linfo || linfo[i].insn_off != off + cnt)) {
16591 		l_cnt--;
16592 		linfo[--i].insn_off = off + cnt;
16593 	}
16594 
16595 	/* remove the line info which refer to the removed instructions */
16596 	if (l_cnt) {
16597 		memmove(linfo + l_off, linfo + i,
16598 			sizeof(*linfo) * (nr_linfo - i));
16599 
16600 		prog->aux->nr_linfo -= l_cnt;
16601 		nr_linfo = prog->aux->nr_linfo;
16602 	}
16603 
16604 	/* pull all linfo[i].insn_off >= off + cnt in by cnt */
16605 	for (i = l_off; i < nr_linfo; i++)
16606 		linfo[i].insn_off -= cnt;
16607 
16608 	/* fix up all subprogs (incl. 'exit') which start >= off */
16609 	for (i = 0; i <= env->subprog_cnt; i++)
16610 		if (env->subprog_info[i].linfo_idx > l_off) {
16611 			/* program may have started in the removed region but
16612 			 * may not be fully removed
16613 			 */
16614 			if (env->subprog_info[i].linfo_idx >= l_off + l_cnt)
16615 				env->subprog_info[i].linfo_idx -= l_cnt;
16616 			else
16617 				env->subprog_info[i].linfo_idx = l_off;
16618 		}
16619 
16620 	return 0;
16621 }
16622 
16623 static int verifier_remove_insns(struct bpf_verifier_env *env, u32 off, u32 cnt)
16624 {
16625 	struct bpf_insn_aux_data *aux_data = env->insn_aux_data;
16626 	unsigned int orig_prog_len = env->prog->len;
16627 	int err;
16628 
16629 	if (bpf_prog_is_offloaded(env->prog->aux))
16630 		bpf_prog_offload_remove_insns(env, off, cnt);
16631 
16632 	err = bpf_remove_insns(env->prog, off, cnt);
16633 	if (err)
16634 		return err;
16635 
16636 	err = adjust_subprog_starts_after_remove(env, off, cnt);
16637 	if (err)
16638 		return err;
16639 
16640 	err = bpf_adj_linfo_after_remove(env, off, cnt);
16641 	if (err)
16642 		return err;
16643 
16644 	memmove(aux_data + off,	aux_data + off + cnt,
16645 		sizeof(*aux_data) * (orig_prog_len - off - cnt));
16646 
16647 	return 0;
16648 }
16649 
16650 /* The verifier does more data flow analysis than llvm and will not
16651  * explore branches that are dead at run time. Malicious programs can
16652  * have dead code too. Therefore replace all dead at-run-time code
16653  * with 'ja -1'.
16654  *
16655  * Just nops are not optimal, e.g. if they would sit at the end of the
16656  * program and through another bug we would manage to jump there, then
16657  * we'd execute beyond program memory otherwise. Returning exception
16658  * code also wouldn't work since we can have subprogs where the dead
16659  * code could be located.
16660  */
16661 static void sanitize_dead_code(struct bpf_verifier_env *env)
16662 {
16663 	struct bpf_insn_aux_data *aux_data = env->insn_aux_data;
16664 	struct bpf_insn trap = BPF_JMP_IMM(BPF_JA, 0, 0, -1);
16665 	struct bpf_insn *insn = env->prog->insnsi;
16666 	const int insn_cnt = env->prog->len;
16667 	int i;
16668 
16669 	for (i = 0; i < insn_cnt; i++) {
16670 		if (aux_data[i].seen)
16671 			continue;
16672 		memcpy(insn + i, &trap, sizeof(trap));
16673 		aux_data[i].zext_dst = false;
16674 	}
16675 }
16676 
16677 static bool insn_is_cond_jump(u8 code)
16678 {
16679 	u8 op;
16680 
16681 	if (BPF_CLASS(code) == BPF_JMP32)
16682 		return true;
16683 
16684 	if (BPF_CLASS(code) != BPF_JMP)
16685 		return false;
16686 
16687 	op = BPF_OP(code);
16688 	return op != BPF_JA && op != BPF_EXIT && op != BPF_CALL;
16689 }
16690 
16691 static void opt_hard_wire_dead_code_branches(struct bpf_verifier_env *env)
16692 {
16693 	struct bpf_insn_aux_data *aux_data = env->insn_aux_data;
16694 	struct bpf_insn ja = BPF_JMP_IMM(BPF_JA, 0, 0, 0);
16695 	struct bpf_insn *insn = env->prog->insnsi;
16696 	const int insn_cnt = env->prog->len;
16697 	int i;
16698 
16699 	for (i = 0; i < insn_cnt; i++, insn++) {
16700 		if (!insn_is_cond_jump(insn->code))
16701 			continue;
16702 
16703 		if (!aux_data[i + 1].seen)
16704 			ja.off = insn->off;
16705 		else if (!aux_data[i + 1 + insn->off].seen)
16706 			ja.off = 0;
16707 		else
16708 			continue;
16709 
16710 		if (bpf_prog_is_offloaded(env->prog->aux))
16711 			bpf_prog_offload_replace_insn(env, i, &ja);
16712 
16713 		memcpy(insn, &ja, sizeof(ja));
16714 	}
16715 }
16716 
16717 static int opt_remove_dead_code(struct bpf_verifier_env *env)
16718 {
16719 	struct bpf_insn_aux_data *aux_data = env->insn_aux_data;
16720 	int insn_cnt = env->prog->len;
16721 	int i, err;
16722 
16723 	for (i = 0; i < insn_cnt; i++) {
16724 		int j;
16725 
16726 		j = 0;
16727 		while (i + j < insn_cnt && !aux_data[i + j].seen)
16728 			j++;
16729 		if (!j)
16730 			continue;
16731 
16732 		err = verifier_remove_insns(env, i, j);
16733 		if (err)
16734 			return err;
16735 		insn_cnt = env->prog->len;
16736 	}
16737 
16738 	return 0;
16739 }
16740 
16741 static int opt_remove_nops(struct bpf_verifier_env *env)
16742 {
16743 	const struct bpf_insn ja = BPF_JMP_IMM(BPF_JA, 0, 0, 0);
16744 	struct bpf_insn *insn = env->prog->insnsi;
16745 	int insn_cnt = env->prog->len;
16746 	int i, err;
16747 
16748 	for (i = 0; i < insn_cnt; i++) {
16749 		if (memcmp(&insn[i], &ja, sizeof(ja)))
16750 			continue;
16751 
16752 		err = verifier_remove_insns(env, i, 1);
16753 		if (err)
16754 			return err;
16755 		insn_cnt--;
16756 		i--;
16757 	}
16758 
16759 	return 0;
16760 }
16761 
16762 static int opt_subreg_zext_lo32_rnd_hi32(struct bpf_verifier_env *env,
16763 					 const union bpf_attr *attr)
16764 {
16765 	struct bpf_insn *patch, zext_patch[2], rnd_hi32_patch[4];
16766 	struct bpf_insn_aux_data *aux = env->insn_aux_data;
16767 	int i, patch_len, delta = 0, len = env->prog->len;
16768 	struct bpf_insn *insns = env->prog->insnsi;
16769 	struct bpf_prog *new_prog;
16770 	bool rnd_hi32;
16771 
16772 	rnd_hi32 = attr->prog_flags & BPF_F_TEST_RND_HI32;
16773 	zext_patch[1] = BPF_ZEXT_REG(0);
16774 	rnd_hi32_patch[1] = BPF_ALU64_IMM(BPF_MOV, BPF_REG_AX, 0);
16775 	rnd_hi32_patch[2] = BPF_ALU64_IMM(BPF_LSH, BPF_REG_AX, 32);
16776 	rnd_hi32_patch[3] = BPF_ALU64_REG(BPF_OR, 0, BPF_REG_AX);
16777 	for (i = 0; i < len; i++) {
16778 		int adj_idx = i + delta;
16779 		struct bpf_insn insn;
16780 		int load_reg;
16781 
16782 		insn = insns[adj_idx];
16783 		load_reg = insn_def_regno(&insn);
16784 		if (!aux[adj_idx].zext_dst) {
16785 			u8 code, class;
16786 			u32 imm_rnd;
16787 
16788 			if (!rnd_hi32)
16789 				continue;
16790 
16791 			code = insn.code;
16792 			class = BPF_CLASS(code);
16793 			if (load_reg == -1)
16794 				continue;
16795 
16796 			/* NOTE: arg "reg" (the fourth one) is only used for
16797 			 *       BPF_STX + SRC_OP, so it is safe to pass NULL
16798 			 *       here.
16799 			 */
16800 			if (is_reg64(env, &insn, load_reg, NULL, DST_OP)) {
16801 				if (class == BPF_LD &&
16802 				    BPF_MODE(code) == BPF_IMM)
16803 					i++;
16804 				continue;
16805 			}
16806 
16807 			/* ctx load could be transformed into wider load. */
16808 			if (class == BPF_LDX &&
16809 			    aux[adj_idx].ptr_type == PTR_TO_CTX)
16810 				continue;
16811 
16812 			imm_rnd = get_random_u32();
16813 			rnd_hi32_patch[0] = insn;
16814 			rnd_hi32_patch[1].imm = imm_rnd;
16815 			rnd_hi32_patch[3].dst_reg = load_reg;
16816 			patch = rnd_hi32_patch;
16817 			patch_len = 4;
16818 			goto apply_patch_buffer;
16819 		}
16820 
16821 		/* Add in an zero-extend instruction if a) the JIT has requested
16822 		 * it or b) it's a CMPXCHG.
16823 		 *
16824 		 * The latter is because: BPF_CMPXCHG always loads a value into
16825 		 * R0, therefore always zero-extends. However some archs'
16826 		 * equivalent instruction only does this load when the
16827 		 * comparison is successful. This detail of CMPXCHG is
16828 		 * orthogonal to the general zero-extension behaviour of the
16829 		 * CPU, so it's treated independently of bpf_jit_needs_zext.
16830 		 */
16831 		if (!bpf_jit_needs_zext() && !is_cmpxchg_insn(&insn))
16832 			continue;
16833 
16834 		/* Zero-extension is done by the caller. */
16835 		if (bpf_pseudo_kfunc_call(&insn))
16836 			continue;
16837 
16838 		if (WARN_ON(load_reg == -1)) {
16839 			verbose(env, "verifier bug. zext_dst is set, but no reg is defined\n");
16840 			return -EFAULT;
16841 		}
16842 
16843 		zext_patch[0] = insn;
16844 		zext_patch[1].dst_reg = load_reg;
16845 		zext_patch[1].src_reg = load_reg;
16846 		patch = zext_patch;
16847 		patch_len = 2;
16848 apply_patch_buffer:
16849 		new_prog = bpf_patch_insn_data(env, adj_idx, patch, patch_len);
16850 		if (!new_prog)
16851 			return -ENOMEM;
16852 		env->prog = new_prog;
16853 		insns = new_prog->insnsi;
16854 		aux = env->insn_aux_data;
16855 		delta += patch_len - 1;
16856 	}
16857 
16858 	return 0;
16859 }
16860 
16861 /* convert load instructions that access fields of a context type into a
16862  * sequence of instructions that access fields of the underlying structure:
16863  *     struct __sk_buff    -> struct sk_buff
16864  *     struct bpf_sock_ops -> struct sock
16865  */
16866 static int convert_ctx_accesses(struct bpf_verifier_env *env)
16867 {
16868 	const struct bpf_verifier_ops *ops = env->ops;
16869 	int i, cnt, size, ctx_field_size, delta = 0;
16870 	const int insn_cnt = env->prog->len;
16871 	struct bpf_insn insn_buf[16], *insn;
16872 	u32 target_size, size_default, off;
16873 	struct bpf_prog *new_prog;
16874 	enum bpf_access_type type;
16875 	bool is_narrower_load;
16876 
16877 	if (ops->gen_prologue || env->seen_direct_write) {
16878 		if (!ops->gen_prologue) {
16879 			verbose(env, "bpf verifier is misconfigured\n");
16880 			return -EINVAL;
16881 		}
16882 		cnt = ops->gen_prologue(insn_buf, env->seen_direct_write,
16883 					env->prog);
16884 		if (cnt >= ARRAY_SIZE(insn_buf)) {
16885 			verbose(env, "bpf verifier is misconfigured\n");
16886 			return -EINVAL;
16887 		} else if (cnt) {
16888 			new_prog = bpf_patch_insn_data(env, 0, insn_buf, cnt);
16889 			if (!new_prog)
16890 				return -ENOMEM;
16891 
16892 			env->prog = new_prog;
16893 			delta += cnt - 1;
16894 		}
16895 	}
16896 
16897 	if (bpf_prog_is_offloaded(env->prog->aux))
16898 		return 0;
16899 
16900 	insn = env->prog->insnsi + delta;
16901 
16902 	for (i = 0; i < insn_cnt; i++, insn++) {
16903 		bpf_convert_ctx_access_t convert_ctx_access;
16904 
16905 		if (insn->code == (BPF_LDX | BPF_MEM | BPF_B) ||
16906 		    insn->code == (BPF_LDX | BPF_MEM | BPF_H) ||
16907 		    insn->code == (BPF_LDX | BPF_MEM | BPF_W) ||
16908 		    insn->code == (BPF_LDX | BPF_MEM | BPF_DW)) {
16909 			type = BPF_READ;
16910 		} else if (insn->code == (BPF_STX | BPF_MEM | BPF_B) ||
16911 			   insn->code == (BPF_STX | BPF_MEM | BPF_H) ||
16912 			   insn->code == (BPF_STX | BPF_MEM | BPF_W) ||
16913 			   insn->code == (BPF_STX | BPF_MEM | BPF_DW) ||
16914 			   insn->code == (BPF_ST | BPF_MEM | BPF_B) ||
16915 			   insn->code == (BPF_ST | BPF_MEM | BPF_H) ||
16916 			   insn->code == (BPF_ST | BPF_MEM | BPF_W) ||
16917 			   insn->code == (BPF_ST | BPF_MEM | BPF_DW)) {
16918 			type = BPF_WRITE;
16919 		} else {
16920 			continue;
16921 		}
16922 
16923 		if (type == BPF_WRITE &&
16924 		    env->insn_aux_data[i + delta].sanitize_stack_spill) {
16925 			struct bpf_insn patch[] = {
16926 				*insn,
16927 				BPF_ST_NOSPEC(),
16928 			};
16929 
16930 			cnt = ARRAY_SIZE(patch);
16931 			new_prog = bpf_patch_insn_data(env, i + delta, patch, cnt);
16932 			if (!new_prog)
16933 				return -ENOMEM;
16934 
16935 			delta    += cnt - 1;
16936 			env->prog = new_prog;
16937 			insn      = new_prog->insnsi + i + delta;
16938 			continue;
16939 		}
16940 
16941 		switch ((int)env->insn_aux_data[i + delta].ptr_type) {
16942 		case PTR_TO_CTX:
16943 			if (!ops->convert_ctx_access)
16944 				continue;
16945 			convert_ctx_access = ops->convert_ctx_access;
16946 			break;
16947 		case PTR_TO_SOCKET:
16948 		case PTR_TO_SOCK_COMMON:
16949 			convert_ctx_access = bpf_sock_convert_ctx_access;
16950 			break;
16951 		case PTR_TO_TCP_SOCK:
16952 			convert_ctx_access = bpf_tcp_sock_convert_ctx_access;
16953 			break;
16954 		case PTR_TO_XDP_SOCK:
16955 			convert_ctx_access = bpf_xdp_sock_convert_ctx_access;
16956 			break;
16957 		case PTR_TO_BTF_ID:
16958 		case PTR_TO_BTF_ID | PTR_UNTRUSTED:
16959 		/* PTR_TO_BTF_ID | MEM_ALLOC always has a valid lifetime, unlike
16960 		 * PTR_TO_BTF_ID, and an active ref_obj_id, but the same cannot
16961 		 * be said once it is marked PTR_UNTRUSTED, hence we must handle
16962 		 * any faults for loads into such types. BPF_WRITE is disallowed
16963 		 * for this case.
16964 		 */
16965 		case PTR_TO_BTF_ID | MEM_ALLOC | PTR_UNTRUSTED:
16966 			if (type == BPF_READ) {
16967 				insn->code = BPF_LDX | BPF_PROBE_MEM |
16968 					BPF_SIZE((insn)->code);
16969 				env->prog->aux->num_exentries++;
16970 			}
16971 			continue;
16972 		default:
16973 			continue;
16974 		}
16975 
16976 		ctx_field_size = env->insn_aux_data[i + delta].ctx_field_size;
16977 		size = BPF_LDST_BYTES(insn);
16978 
16979 		/* If the read access is a narrower load of the field,
16980 		 * convert to a 4/8-byte load, to minimum program type specific
16981 		 * convert_ctx_access changes. If conversion is successful,
16982 		 * we will apply proper mask to the result.
16983 		 */
16984 		is_narrower_load = size < ctx_field_size;
16985 		size_default = bpf_ctx_off_adjust_machine(ctx_field_size);
16986 		off = insn->off;
16987 		if (is_narrower_load) {
16988 			u8 size_code;
16989 
16990 			if (type == BPF_WRITE) {
16991 				verbose(env, "bpf verifier narrow ctx access misconfigured\n");
16992 				return -EINVAL;
16993 			}
16994 
16995 			size_code = BPF_H;
16996 			if (ctx_field_size == 4)
16997 				size_code = BPF_W;
16998 			else if (ctx_field_size == 8)
16999 				size_code = BPF_DW;
17000 
17001 			insn->off = off & ~(size_default - 1);
17002 			insn->code = BPF_LDX | BPF_MEM | size_code;
17003 		}
17004 
17005 		target_size = 0;
17006 		cnt = convert_ctx_access(type, insn, insn_buf, env->prog,
17007 					 &target_size);
17008 		if (cnt == 0 || cnt >= ARRAY_SIZE(insn_buf) ||
17009 		    (ctx_field_size && !target_size)) {
17010 			verbose(env, "bpf verifier is misconfigured\n");
17011 			return -EINVAL;
17012 		}
17013 
17014 		if (is_narrower_load && size < target_size) {
17015 			u8 shift = bpf_ctx_narrow_access_offset(
17016 				off, size, size_default) * 8;
17017 			if (shift && cnt + 1 >= ARRAY_SIZE(insn_buf)) {
17018 				verbose(env, "bpf verifier narrow ctx load misconfigured\n");
17019 				return -EINVAL;
17020 			}
17021 			if (ctx_field_size <= 4) {
17022 				if (shift)
17023 					insn_buf[cnt++] = BPF_ALU32_IMM(BPF_RSH,
17024 									insn->dst_reg,
17025 									shift);
17026 				insn_buf[cnt++] = BPF_ALU32_IMM(BPF_AND, insn->dst_reg,
17027 								(1 << size * 8) - 1);
17028 			} else {
17029 				if (shift)
17030 					insn_buf[cnt++] = BPF_ALU64_IMM(BPF_RSH,
17031 									insn->dst_reg,
17032 									shift);
17033 				insn_buf[cnt++] = BPF_ALU64_IMM(BPF_AND, insn->dst_reg,
17034 								(1ULL << size * 8) - 1);
17035 			}
17036 		}
17037 
17038 		new_prog = bpf_patch_insn_data(env, i + delta, insn_buf, cnt);
17039 		if (!new_prog)
17040 			return -ENOMEM;
17041 
17042 		delta += cnt - 1;
17043 
17044 		/* keep walking new program and skip insns we just inserted */
17045 		env->prog = new_prog;
17046 		insn      = new_prog->insnsi + i + delta;
17047 	}
17048 
17049 	return 0;
17050 }
17051 
17052 static int jit_subprogs(struct bpf_verifier_env *env)
17053 {
17054 	struct bpf_prog *prog = env->prog, **func, *tmp;
17055 	int i, j, subprog_start, subprog_end = 0, len, subprog;
17056 	struct bpf_map *map_ptr;
17057 	struct bpf_insn *insn;
17058 	void *old_bpf_func;
17059 	int err, num_exentries;
17060 
17061 	if (env->subprog_cnt <= 1)
17062 		return 0;
17063 
17064 	for (i = 0, insn = prog->insnsi; i < prog->len; i++, insn++) {
17065 		if (!bpf_pseudo_func(insn) && !bpf_pseudo_call(insn))
17066 			continue;
17067 
17068 		/* Upon error here we cannot fall back to interpreter but
17069 		 * need a hard reject of the program. Thus -EFAULT is
17070 		 * propagated in any case.
17071 		 */
17072 		subprog = find_subprog(env, i + insn->imm + 1);
17073 		if (subprog < 0) {
17074 			WARN_ONCE(1, "verifier bug. No program starts at insn %d\n",
17075 				  i + insn->imm + 1);
17076 			return -EFAULT;
17077 		}
17078 		/* temporarily remember subprog id inside insn instead of
17079 		 * aux_data, since next loop will split up all insns into funcs
17080 		 */
17081 		insn->off = subprog;
17082 		/* remember original imm in case JIT fails and fallback
17083 		 * to interpreter will be needed
17084 		 */
17085 		env->insn_aux_data[i].call_imm = insn->imm;
17086 		/* point imm to __bpf_call_base+1 from JITs point of view */
17087 		insn->imm = 1;
17088 		if (bpf_pseudo_func(insn))
17089 			/* jit (e.g. x86_64) may emit fewer instructions
17090 			 * if it learns a u32 imm is the same as a u64 imm.
17091 			 * Force a non zero here.
17092 			 */
17093 			insn[1].imm = 1;
17094 	}
17095 
17096 	err = bpf_prog_alloc_jited_linfo(prog);
17097 	if (err)
17098 		goto out_undo_insn;
17099 
17100 	err = -ENOMEM;
17101 	func = kcalloc(env->subprog_cnt, sizeof(prog), GFP_KERNEL);
17102 	if (!func)
17103 		goto out_undo_insn;
17104 
17105 	for (i = 0; i < env->subprog_cnt; i++) {
17106 		subprog_start = subprog_end;
17107 		subprog_end = env->subprog_info[i + 1].start;
17108 
17109 		len = subprog_end - subprog_start;
17110 		/* bpf_prog_run() doesn't call subprogs directly,
17111 		 * hence main prog stats include the runtime of subprogs.
17112 		 * subprogs don't have IDs and not reachable via prog_get_next_id
17113 		 * func[i]->stats will never be accessed and stays NULL
17114 		 */
17115 		func[i] = bpf_prog_alloc_no_stats(bpf_prog_size(len), GFP_USER);
17116 		if (!func[i])
17117 			goto out_free;
17118 		memcpy(func[i]->insnsi, &prog->insnsi[subprog_start],
17119 		       len * sizeof(struct bpf_insn));
17120 		func[i]->type = prog->type;
17121 		func[i]->len = len;
17122 		if (bpf_prog_calc_tag(func[i]))
17123 			goto out_free;
17124 		func[i]->is_func = 1;
17125 		func[i]->aux->func_idx = i;
17126 		/* Below members will be freed only at prog->aux */
17127 		func[i]->aux->btf = prog->aux->btf;
17128 		func[i]->aux->func_info = prog->aux->func_info;
17129 		func[i]->aux->func_info_cnt = prog->aux->func_info_cnt;
17130 		func[i]->aux->poke_tab = prog->aux->poke_tab;
17131 		func[i]->aux->size_poke_tab = prog->aux->size_poke_tab;
17132 
17133 		for (j = 0; j < prog->aux->size_poke_tab; j++) {
17134 			struct bpf_jit_poke_descriptor *poke;
17135 
17136 			poke = &prog->aux->poke_tab[j];
17137 			if (poke->insn_idx < subprog_end &&
17138 			    poke->insn_idx >= subprog_start)
17139 				poke->aux = func[i]->aux;
17140 		}
17141 
17142 		func[i]->aux->name[0] = 'F';
17143 		func[i]->aux->stack_depth = env->subprog_info[i].stack_depth;
17144 		func[i]->jit_requested = 1;
17145 		func[i]->blinding_requested = prog->blinding_requested;
17146 		func[i]->aux->kfunc_tab = prog->aux->kfunc_tab;
17147 		func[i]->aux->kfunc_btf_tab = prog->aux->kfunc_btf_tab;
17148 		func[i]->aux->linfo = prog->aux->linfo;
17149 		func[i]->aux->nr_linfo = prog->aux->nr_linfo;
17150 		func[i]->aux->jited_linfo = prog->aux->jited_linfo;
17151 		func[i]->aux->linfo_idx = env->subprog_info[i].linfo_idx;
17152 		num_exentries = 0;
17153 		insn = func[i]->insnsi;
17154 		for (j = 0; j < func[i]->len; j++, insn++) {
17155 			if (BPF_CLASS(insn->code) == BPF_LDX &&
17156 			    BPF_MODE(insn->code) == BPF_PROBE_MEM)
17157 				num_exentries++;
17158 		}
17159 		func[i]->aux->num_exentries = num_exentries;
17160 		func[i]->aux->tail_call_reachable = env->subprog_info[i].tail_call_reachable;
17161 		func[i] = bpf_int_jit_compile(func[i]);
17162 		if (!func[i]->jited) {
17163 			err = -ENOTSUPP;
17164 			goto out_free;
17165 		}
17166 		cond_resched();
17167 	}
17168 
17169 	/* at this point all bpf functions were successfully JITed
17170 	 * now populate all bpf_calls with correct addresses and
17171 	 * run last pass of JIT
17172 	 */
17173 	for (i = 0; i < env->subprog_cnt; i++) {
17174 		insn = func[i]->insnsi;
17175 		for (j = 0; j < func[i]->len; j++, insn++) {
17176 			if (bpf_pseudo_func(insn)) {
17177 				subprog = insn->off;
17178 				insn[0].imm = (u32)(long)func[subprog]->bpf_func;
17179 				insn[1].imm = ((u64)(long)func[subprog]->bpf_func) >> 32;
17180 				continue;
17181 			}
17182 			if (!bpf_pseudo_call(insn))
17183 				continue;
17184 			subprog = insn->off;
17185 			insn->imm = BPF_CALL_IMM(func[subprog]->bpf_func);
17186 		}
17187 
17188 		/* we use the aux data to keep a list of the start addresses
17189 		 * of the JITed images for each function in the program
17190 		 *
17191 		 * for some architectures, such as powerpc64, the imm field
17192 		 * might not be large enough to hold the offset of the start
17193 		 * address of the callee's JITed image from __bpf_call_base
17194 		 *
17195 		 * in such cases, we can lookup the start address of a callee
17196 		 * by using its subprog id, available from the off field of
17197 		 * the call instruction, as an index for this list
17198 		 */
17199 		func[i]->aux->func = func;
17200 		func[i]->aux->func_cnt = env->subprog_cnt;
17201 	}
17202 	for (i = 0; i < env->subprog_cnt; i++) {
17203 		old_bpf_func = func[i]->bpf_func;
17204 		tmp = bpf_int_jit_compile(func[i]);
17205 		if (tmp != func[i] || func[i]->bpf_func != old_bpf_func) {
17206 			verbose(env, "JIT doesn't support bpf-to-bpf calls\n");
17207 			err = -ENOTSUPP;
17208 			goto out_free;
17209 		}
17210 		cond_resched();
17211 	}
17212 
17213 	/* finally lock prog and jit images for all functions and
17214 	 * populate kallsysm
17215 	 */
17216 	for (i = 0; i < env->subprog_cnt; i++) {
17217 		bpf_prog_lock_ro(func[i]);
17218 		bpf_prog_kallsyms_add(func[i]);
17219 	}
17220 
17221 	/* Last step: make now unused interpreter insns from main
17222 	 * prog consistent for later dump requests, so they can
17223 	 * later look the same as if they were interpreted only.
17224 	 */
17225 	for (i = 0, insn = prog->insnsi; i < prog->len; i++, insn++) {
17226 		if (bpf_pseudo_func(insn)) {
17227 			insn[0].imm = env->insn_aux_data[i].call_imm;
17228 			insn[1].imm = insn->off;
17229 			insn->off = 0;
17230 			continue;
17231 		}
17232 		if (!bpf_pseudo_call(insn))
17233 			continue;
17234 		insn->off = env->insn_aux_data[i].call_imm;
17235 		subprog = find_subprog(env, i + insn->off + 1);
17236 		insn->imm = subprog;
17237 	}
17238 
17239 	prog->jited = 1;
17240 	prog->bpf_func = func[0]->bpf_func;
17241 	prog->jited_len = func[0]->jited_len;
17242 	prog->aux->func = func;
17243 	prog->aux->func_cnt = env->subprog_cnt;
17244 	bpf_prog_jit_attempt_done(prog);
17245 	return 0;
17246 out_free:
17247 	/* We failed JIT'ing, so at this point we need to unregister poke
17248 	 * descriptors from subprogs, so that kernel is not attempting to
17249 	 * patch it anymore as we're freeing the subprog JIT memory.
17250 	 */
17251 	for (i = 0; i < prog->aux->size_poke_tab; i++) {
17252 		map_ptr = prog->aux->poke_tab[i].tail_call.map;
17253 		map_ptr->ops->map_poke_untrack(map_ptr, prog->aux);
17254 	}
17255 	/* At this point we're guaranteed that poke descriptors are not
17256 	 * live anymore. We can just unlink its descriptor table as it's
17257 	 * released with the main prog.
17258 	 */
17259 	for (i = 0; i < env->subprog_cnt; i++) {
17260 		if (!func[i])
17261 			continue;
17262 		func[i]->aux->poke_tab = NULL;
17263 		bpf_jit_free(func[i]);
17264 	}
17265 	kfree(func);
17266 out_undo_insn:
17267 	/* cleanup main prog to be interpreted */
17268 	prog->jit_requested = 0;
17269 	prog->blinding_requested = 0;
17270 	for (i = 0, insn = prog->insnsi; i < prog->len; i++, insn++) {
17271 		if (!bpf_pseudo_call(insn))
17272 			continue;
17273 		insn->off = 0;
17274 		insn->imm = env->insn_aux_data[i].call_imm;
17275 	}
17276 	bpf_prog_jit_attempt_done(prog);
17277 	return err;
17278 }
17279 
17280 static int fixup_call_args(struct bpf_verifier_env *env)
17281 {
17282 #ifndef CONFIG_BPF_JIT_ALWAYS_ON
17283 	struct bpf_prog *prog = env->prog;
17284 	struct bpf_insn *insn = prog->insnsi;
17285 	bool has_kfunc_call = bpf_prog_has_kfunc_call(prog);
17286 	int i, depth;
17287 #endif
17288 	int err = 0;
17289 
17290 	if (env->prog->jit_requested &&
17291 	    !bpf_prog_is_offloaded(env->prog->aux)) {
17292 		err = jit_subprogs(env);
17293 		if (err == 0)
17294 			return 0;
17295 		if (err == -EFAULT)
17296 			return err;
17297 	}
17298 #ifndef CONFIG_BPF_JIT_ALWAYS_ON
17299 	if (has_kfunc_call) {
17300 		verbose(env, "calling kernel functions are not allowed in non-JITed programs\n");
17301 		return -EINVAL;
17302 	}
17303 	if (env->subprog_cnt > 1 && env->prog->aux->tail_call_reachable) {
17304 		/* When JIT fails the progs with bpf2bpf calls and tail_calls
17305 		 * have to be rejected, since interpreter doesn't support them yet.
17306 		 */
17307 		verbose(env, "tail_calls are not allowed in non-JITed programs with bpf-to-bpf calls\n");
17308 		return -EINVAL;
17309 	}
17310 	for (i = 0; i < prog->len; i++, insn++) {
17311 		if (bpf_pseudo_func(insn)) {
17312 			/* When JIT fails the progs with callback calls
17313 			 * have to be rejected, since interpreter doesn't support them yet.
17314 			 */
17315 			verbose(env, "callbacks are not allowed in non-JITed programs\n");
17316 			return -EINVAL;
17317 		}
17318 
17319 		if (!bpf_pseudo_call(insn))
17320 			continue;
17321 		depth = get_callee_stack_depth(env, insn, i);
17322 		if (depth < 0)
17323 			return depth;
17324 		bpf_patch_call_args(insn, depth);
17325 	}
17326 	err = 0;
17327 #endif
17328 	return err;
17329 }
17330 
17331 /* replace a generic kfunc with a specialized version if necessary */
17332 static void specialize_kfunc(struct bpf_verifier_env *env,
17333 			     u32 func_id, u16 offset, unsigned long *addr)
17334 {
17335 	struct bpf_prog *prog = env->prog;
17336 	bool seen_direct_write;
17337 	void *xdp_kfunc;
17338 	bool is_rdonly;
17339 
17340 	if (bpf_dev_bound_kfunc_id(func_id)) {
17341 		xdp_kfunc = bpf_dev_bound_resolve_kfunc(prog, func_id);
17342 		if (xdp_kfunc) {
17343 			*addr = (unsigned long)xdp_kfunc;
17344 			return;
17345 		}
17346 		/* fallback to default kfunc when not supported by netdev */
17347 	}
17348 
17349 	if (offset)
17350 		return;
17351 
17352 	if (func_id == special_kfunc_list[KF_bpf_dynptr_from_skb]) {
17353 		seen_direct_write = env->seen_direct_write;
17354 		is_rdonly = !may_access_direct_pkt_data(env, NULL, BPF_WRITE);
17355 
17356 		if (is_rdonly)
17357 			*addr = (unsigned long)bpf_dynptr_from_skb_rdonly;
17358 
17359 		/* restore env->seen_direct_write to its original value, since
17360 		 * may_access_direct_pkt_data mutates it
17361 		 */
17362 		env->seen_direct_write = seen_direct_write;
17363 	}
17364 }
17365 
17366 static void __fixup_collection_insert_kfunc(struct bpf_insn_aux_data *insn_aux,
17367 					    u16 struct_meta_reg,
17368 					    u16 node_offset_reg,
17369 					    struct bpf_insn *insn,
17370 					    struct bpf_insn *insn_buf,
17371 					    int *cnt)
17372 {
17373 	struct btf_struct_meta *kptr_struct_meta = insn_aux->kptr_struct_meta;
17374 	struct bpf_insn addr[2] = { BPF_LD_IMM64(struct_meta_reg, (long)kptr_struct_meta) };
17375 
17376 	insn_buf[0] = addr[0];
17377 	insn_buf[1] = addr[1];
17378 	insn_buf[2] = BPF_MOV64_IMM(node_offset_reg, insn_aux->insert_off);
17379 	insn_buf[3] = *insn;
17380 	*cnt = 4;
17381 }
17382 
17383 static int fixup_kfunc_call(struct bpf_verifier_env *env, struct bpf_insn *insn,
17384 			    struct bpf_insn *insn_buf, int insn_idx, int *cnt)
17385 {
17386 	const struct bpf_kfunc_desc *desc;
17387 
17388 	if (!insn->imm) {
17389 		verbose(env, "invalid kernel function call not eliminated in verifier pass\n");
17390 		return -EINVAL;
17391 	}
17392 
17393 	*cnt = 0;
17394 
17395 	/* insn->imm has the btf func_id. Replace it with an offset relative to
17396 	 * __bpf_call_base, unless the JIT needs to call functions that are
17397 	 * further than 32 bits away (bpf_jit_supports_far_kfunc_call()).
17398 	 */
17399 	desc = find_kfunc_desc(env->prog, insn->imm, insn->off);
17400 	if (!desc) {
17401 		verbose(env, "verifier internal error: kernel function descriptor not found for func_id %u\n",
17402 			insn->imm);
17403 		return -EFAULT;
17404 	}
17405 
17406 	if (!bpf_jit_supports_far_kfunc_call())
17407 		insn->imm = BPF_CALL_IMM(desc->addr);
17408 	if (insn->off)
17409 		return 0;
17410 	if (desc->func_id == special_kfunc_list[KF_bpf_obj_new_impl]) {
17411 		struct btf_struct_meta *kptr_struct_meta = env->insn_aux_data[insn_idx].kptr_struct_meta;
17412 		struct bpf_insn addr[2] = { BPF_LD_IMM64(BPF_REG_2, (long)kptr_struct_meta) };
17413 		u64 obj_new_size = env->insn_aux_data[insn_idx].obj_new_size;
17414 
17415 		insn_buf[0] = BPF_MOV64_IMM(BPF_REG_1, obj_new_size);
17416 		insn_buf[1] = addr[0];
17417 		insn_buf[2] = addr[1];
17418 		insn_buf[3] = *insn;
17419 		*cnt = 4;
17420 	} else if (desc->func_id == special_kfunc_list[KF_bpf_obj_drop_impl] ||
17421 		   desc->func_id == special_kfunc_list[KF_bpf_refcount_acquire_impl]) {
17422 		struct btf_struct_meta *kptr_struct_meta = env->insn_aux_data[insn_idx].kptr_struct_meta;
17423 		struct bpf_insn addr[2] = { BPF_LD_IMM64(BPF_REG_2, (long)kptr_struct_meta) };
17424 
17425 		insn_buf[0] = addr[0];
17426 		insn_buf[1] = addr[1];
17427 		insn_buf[2] = *insn;
17428 		*cnt = 3;
17429 	} else if (desc->func_id == special_kfunc_list[KF_bpf_list_push_back_impl] ||
17430 		   desc->func_id == special_kfunc_list[KF_bpf_list_push_front_impl] ||
17431 		   desc->func_id == special_kfunc_list[KF_bpf_rbtree_add_impl]) {
17432 		int struct_meta_reg = BPF_REG_3;
17433 		int node_offset_reg = BPF_REG_4;
17434 
17435 		/* rbtree_add has extra 'less' arg, so args-to-fixup are in diff regs */
17436 		if (desc->func_id == special_kfunc_list[KF_bpf_rbtree_add_impl]) {
17437 			struct_meta_reg = BPF_REG_4;
17438 			node_offset_reg = BPF_REG_5;
17439 		}
17440 
17441 		__fixup_collection_insert_kfunc(&env->insn_aux_data[insn_idx], struct_meta_reg,
17442 						node_offset_reg, insn, insn_buf, cnt);
17443 	} else if (desc->func_id == special_kfunc_list[KF_bpf_cast_to_kern_ctx] ||
17444 		   desc->func_id == special_kfunc_list[KF_bpf_rdonly_cast]) {
17445 		insn_buf[0] = BPF_MOV64_REG(BPF_REG_0, BPF_REG_1);
17446 		*cnt = 1;
17447 	}
17448 	return 0;
17449 }
17450 
17451 /* Do various post-verification rewrites in a single program pass.
17452  * These rewrites simplify JIT and interpreter implementations.
17453  */
17454 static int do_misc_fixups(struct bpf_verifier_env *env)
17455 {
17456 	struct bpf_prog *prog = env->prog;
17457 	enum bpf_attach_type eatype = prog->expected_attach_type;
17458 	enum bpf_prog_type prog_type = resolve_prog_type(prog);
17459 	struct bpf_insn *insn = prog->insnsi;
17460 	const struct bpf_func_proto *fn;
17461 	const int insn_cnt = prog->len;
17462 	const struct bpf_map_ops *ops;
17463 	struct bpf_insn_aux_data *aux;
17464 	struct bpf_insn insn_buf[16];
17465 	struct bpf_prog *new_prog;
17466 	struct bpf_map *map_ptr;
17467 	int i, ret, cnt, delta = 0;
17468 
17469 	for (i = 0; i < insn_cnt; i++, insn++) {
17470 		/* Make divide-by-zero exceptions impossible. */
17471 		if (insn->code == (BPF_ALU64 | BPF_MOD | BPF_X) ||
17472 		    insn->code == (BPF_ALU64 | BPF_DIV | BPF_X) ||
17473 		    insn->code == (BPF_ALU | BPF_MOD | BPF_X) ||
17474 		    insn->code == (BPF_ALU | BPF_DIV | BPF_X)) {
17475 			bool is64 = BPF_CLASS(insn->code) == BPF_ALU64;
17476 			bool isdiv = BPF_OP(insn->code) == BPF_DIV;
17477 			struct bpf_insn *patchlet;
17478 			struct bpf_insn chk_and_div[] = {
17479 				/* [R,W]x div 0 -> 0 */
17480 				BPF_RAW_INSN((is64 ? BPF_JMP : BPF_JMP32) |
17481 					     BPF_JNE | BPF_K, insn->src_reg,
17482 					     0, 2, 0),
17483 				BPF_ALU32_REG(BPF_XOR, insn->dst_reg, insn->dst_reg),
17484 				BPF_JMP_IMM(BPF_JA, 0, 0, 1),
17485 				*insn,
17486 			};
17487 			struct bpf_insn chk_and_mod[] = {
17488 				/* [R,W]x mod 0 -> [R,W]x */
17489 				BPF_RAW_INSN((is64 ? BPF_JMP : BPF_JMP32) |
17490 					     BPF_JEQ | BPF_K, insn->src_reg,
17491 					     0, 1 + (is64 ? 0 : 1), 0),
17492 				*insn,
17493 				BPF_JMP_IMM(BPF_JA, 0, 0, 1),
17494 				BPF_MOV32_REG(insn->dst_reg, insn->dst_reg),
17495 			};
17496 
17497 			patchlet = isdiv ? chk_and_div : chk_and_mod;
17498 			cnt = isdiv ? ARRAY_SIZE(chk_and_div) :
17499 				      ARRAY_SIZE(chk_and_mod) - (is64 ? 2 : 0);
17500 
17501 			new_prog = bpf_patch_insn_data(env, i + delta, patchlet, cnt);
17502 			if (!new_prog)
17503 				return -ENOMEM;
17504 
17505 			delta    += cnt - 1;
17506 			env->prog = prog = new_prog;
17507 			insn      = new_prog->insnsi + i + delta;
17508 			continue;
17509 		}
17510 
17511 		/* Implement LD_ABS and LD_IND with a rewrite, if supported by the program type. */
17512 		if (BPF_CLASS(insn->code) == BPF_LD &&
17513 		    (BPF_MODE(insn->code) == BPF_ABS ||
17514 		     BPF_MODE(insn->code) == BPF_IND)) {
17515 			cnt = env->ops->gen_ld_abs(insn, insn_buf);
17516 			if (cnt == 0 || cnt >= ARRAY_SIZE(insn_buf)) {
17517 				verbose(env, "bpf verifier is misconfigured\n");
17518 				return -EINVAL;
17519 			}
17520 
17521 			new_prog = bpf_patch_insn_data(env, i + delta, insn_buf, cnt);
17522 			if (!new_prog)
17523 				return -ENOMEM;
17524 
17525 			delta    += cnt - 1;
17526 			env->prog = prog = new_prog;
17527 			insn      = new_prog->insnsi + i + delta;
17528 			continue;
17529 		}
17530 
17531 		/* Rewrite pointer arithmetic to mitigate speculation attacks. */
17532 		if (insn->code == (BPF_ALU64 | BPF_ADD | BPF_X) ||
17533 		    insn->code == (BPF_ALU64 | BPF_SUB | BPF_X)) {
17534 			const u8 code_add = BPF_ALU64 | BPF_ADD | BPF_X;
17535 			const u8 code_sub = BPF_ALU64 | BPF_SUB | BPF_X;
17536 			struct bpf_insn *patch = &insn_buf[0];
17537 			bool issrc, isneg, isimm;
17538 			u32 off_reg;
17539 
17540 			aux = &env->insn_aux_data[i + delta];
17541 			if (!aux->alu_state ||
17542 			    aux->alu_state == BPF_ALU_NON_POINTER)
17543 				continue;
17544 
17545 			isneg = aux->alu_state & BPF_ALU_NEG_VALUE;
17546 			issrc = (aux->alu_state & BPF_ALU_SANITIZE) ==
17547 				BPF_ALU_SANITIZE_SRC;
17548 			isimm = aux->alu_state & BPF_ALU_IMMEDIATE;
17549 
17550 			off_reg = issrc ? insn->src_reg : insn->dst_reg;
17551 			if (isimm) {
17552 				*patch++ = BPF_MOV32_IMM(BPF_REG_AX, aux->alu_limit);
17553 			} else {
17554 				if (isneg)
17555 					*patch++ = BPF_ALU64_IMM(BPF_MUL, off_reg, -1);
17556 				*patch++ = BPF_MOV32_IMM(BPF_REG_AX, aux->alu_limit);
17557 				*patch++ = BPF_ALU64_REG(BPF_SUB, BPF_REG_AX, off_reg);
17558 				*patch++ = BPF_ALU64_REG(BPF_OR, BPF_REG_AX, off_reg);
17559 				*patch++ = BPF_ALU64_IMM(BPF_NEG, BPF_REG_AX, 0);
17560 				*patch++ = BPF_ALU64_IMM(BPF_ARSH, BPF_REG_AX, 63);
17561 				*patch++ = BPF_ALU64_REG(BPF_AND, BPF_REG_AX, off_reg);
17562 			}
17563 			if (!issrc)
17564 				*patch++ = BPF_MOV64_REG(insn->dst_reg, insn->src_reg);
17565 			insn->src_reg = BPF_REG_AX;
17566 			if (isneg)
17567 				insn->code = insn->code == code_add ?
17568 					     code_sub : code_add;
17569 			*patch++ = *insn;
17570 			if (issrc && isneg && !isimm)
17571 				*patch++ = BPF_ALU64_IMM(BPF_MUL, off_reg, -1);
17572 			cnt = patch - insn_buf;
17573 
17574 			new_prog = bpf_patch_insn_data(env, i + delta, insn_buf, cnt);
17575 			if (!new_prog)
17576 				return -ENOMEM;
17577 
17578 			delta    += cnt - 1;
17579 			env->prog = prog = new_prog;
17580 			insn      = new_prog->insnsi + i + delta;
17581 			continue;
17582 		}
17583 
17584 		if (insn->code != (BPF_JMP | BPF_CALL))
17585 			continue;
17586 		if (insn->src_reg == BPF_PSEUDO_CALL)
17587 			continue;
17588 		if (insn->src_reg == BPF_PSEUDO_KFUNC_CALL) {
17589 			ret = fixup_kfunc_call(env, insn, insn_buf, i + delta, &cnt);
17590 			if (ret)
17591 				return ret;
17592 			if (cnt == 0)
17593 				continue;
17594 
17595 			new_prog = bpf_patch_insn_data(env, i + delta, insn_buf, cnt);
17596 			if (!new_prog)
17597 				return -ENOMEM;
17598 
17599 			delta	 += cnt - 1;
17600 			env->prog = prog = new_prog;
17601 			insn	  = new_prog->insnsi + i + delta;
17602 			continue;
17603 		}
17604 
17605 		if (insn->imm == BPF_FUNC_get_route_realm)
17606 			prog->dst_needed = 1;
17607 		if (insn->imm == BPF_FUNC_get_prandom_u32)
17608 			bpf_user_rnd_init_once();
17609 		if (insn->imm == BPF_FUNC_override_return)
17610 			prog->kprobe_override = 1;
17611 		if (insn->imm == BPF_FUNC_tail_call) {
17612 			/* If we tail call into other programs, we
17613 			 * cannot make any assumptions since they can
17614 			 * be replaced dynamically during runtime in
17615 			 * the program array.
17616 			 */
17617 			prog->cb_access = 1;
17618 			if (!allow_tail_call_in_subprogs(env))
17619 				prog->aux->stack_depth = MAX_BPF_STACK;
17620 			prog->aux->max_pkt_offset = MAX_PACKET_OFF;
17621 
17622 			/* mark bpf_tail_call as different opcode to avoid
17623 			 * conditional branch in the interpreter for every normal
17624 			 * call and to prevent accidental JITing by JIT compiler
17625 			 * that doesn't support bpf_tail_call yet
17626 			 */
17627 			insn->imm = 0;
17628 			insn->code = BPF_JMP | BPF_TAIL_CALL;
17629 
17630 			aux = &env->insn_aux_data[i + delta];
17631 			if (env->bpf_capable && !prog->blinding_requested &&
17632 			    prog->jit_requested &&
17633 			    !bpf_map_key_poisoned(aux) &&
17634 			    !bpf_map_ptr_poisoned(aux) &&
17635 			    !bpf_map_ptr_unpriv(aux)) {
17636 				struct bpf_jit_poke_descriptor desc = {
17637 					.reason = BPF_POKE_REASON_TAIL_CALL,
17638 					.tail_call.map = BPF_MAP_PTR(aux->map_ptr_state),
17639 					.tail_call.key = bpf_map_key_immediate(aux),
17640 					.insn_idx = i + delta,
17641 				};
17642 
17643 				ret = bpf_jit_add_poke_descriptor(prog, &desc);
17644 				if (ret < 0) {
17645 					verbose(env, "adding tail call poke descriptor failed\n");
17646 					return ret;
17647 				}
17648 
17649 				insn->imm = ret + 1;
17650 				continue;
17651 			}
17652 
17653 			if (!bpf_map_ptr_unpriv(aux))
17654 				continue;
17655 
17656 			/* instead of changing every JIT dealing with tail_call
17657 			 * emit two extra insns:
17658 			 * if (index >= max_entries) goto out;
17659 			 * index &= array->index_mask;
17660 			 * to avoid out-of-bounds cpu speculation
17661 			 */
17662 			if (bpf_map_ptr_poisoned(aux)) {
17663 				verbose(env, "tail_call abusing map_ptr\n");
17664 				return -EINVAL;
17665 			}
17666 
17667 			map_ptr = BPF_MAP_PTR(aux->map_ptr_state);
17668 			insn_buf[0] = BPF_JMP_IMM(BPF_JGE, BPF_REG_3,
17669 						  map_ptr->max_entries, 2);
17670 			insn_buf[1] = BPF_ALU32_IMM(BPF_AND, BPF_REG_3,
17671 						    container_of(map_ptr,
17672 								 struct bpf_array,
17673 								 map)->index_mask);
17674 			insn_buf[2] = *insn;
17675 			cnt = 3;
17676 			new_prog = bpf_patch_insn_data(env, i + delta, insn_buf, cnt);
17677 			if (!new_prog)
17678 				return -ENOMEM;
17679 
17680 			delta    += cnt - 1;
17681 			env->prog = prog = new_prog;
17682 			insn      = new_prog->insnsi + i + delta;
17683 			continue;
17684 		}
17685 
17686 		if (insn->imm == BPF_FUNC_timer_set_callback) {
17687 			/* The verifier will process callback_fn as many times as necessary
17688 			 * with different maps and the register states prepared by
17689 			 * set_timer_callback_state will be accurate.
17690 			 *
17691 			 * The following use case is valid:
17692 			 *   map1 is shared by prog1, prog2, prog3.
17693 			 *   prog1 calls bpf_timer_init for some map1 elements
17694 			 *   prog2 calls bpf_timer_set_callback for some map1 elements.
17695 			 *     Those that were not bpf_timer_init-ed will return -EINVAL.
17696 			 *   prog3 calls bpf_timer_start for some map1 elements.
17697 			 *     Those that were not both bpf_timer_init-ed and
17698 			 *     bpf_timer_set_callback-ed will return -EINVAL.
17699 			 */
17700 			struct bpf_insn ld_addrs[2] = {
17701 				BPF_LD_IMM64(BPF_REG_3, (long)prog->aux),
17702 			};
17703 
17704 			insn_buf[0] = ld_addrs[0];
17705 			insn_buf[1] = ld_addrs[1];
17706 			insn_buf[2] = *insn;
17707 			cnt = 3;
17708 
17709 			new_prog = bpf_patch_insn_data(env, i + delta, insn_buf, cnt);
17710 			if (!new_prog)
17711 				return -ENOMEM;
17712 
17713 			delta    += cnt - 1;
17714 			env->prog = prog = new_prog;
17715 			insn      = new_prog->insnsi + i + delta;
17716 			goto patch_call_imm;
17717 		}
17718 
17719 		if (is_storage_get_function(insn->imm)) {
17720 			if (!env->prog->aux->sleepable ||
17721 			    env->insn_aux_data[i + delta].storage_get_func_atomic)
17722 				insn_buf[0] = BPF_MOV64_IMM(BPF_REG_5, (__force __s32)GFP_ATOMIC);
17723 			else
17724 				insn_buf[0] = BPF_MOV64_IMM(BPF_REG_5, (__force __s32)GFP_KERNEL);
17725 			insn_buf[1] = *insn;
17726 			cnt = 2;
17727 
17728 			new_prog = bpf_patch_insn_data(env, i + delta, insn_buf, cnt);
17729 			if (!new_prog)
17730 				return -ENOMEM;
17731 
17732 			delta += cnt - 1;
17733 			env->prog = prog = new_prog;
17734 			insn = new_prog->insnsi + i + delta;
17735 			goto patch_call_imm;
17736 		}
17737 
17738 		/* BPF_EMIT_CALL() assumptions in some of the map_gen_lookup
17739 		 * and other inlining handlers are currently limited to 64 bit
17740 		 * only.
17741 		 */
17742 		if (prog->jit_requested && BITS_PER_LONG == 64 &&
17743 		    (insn->imm == BPF_FUNC_map_lookup_elem ||
17744 		     insn->imm == BPF_FUNC_map_update_elem ||
17745 		     insn->imm == BPF_FUNC_map_delete_elem ||
17746 		     insn->imm == BPF_FUNC_map_push_elem   ||
17747 		     insn->imm == BPF_FUNC_map_pop_elem    ||
17748 		     insn->imm == BPF_FUNC_map_peek_elem   ||
17749 		     insn->imm == BPF_FUNC_redirect_map    ||
17750 		     insn->imm == BPF_FUNC_for_each_map_elem ||
17751 		     insn->imm == BPF_FUNC_map_lookup_percpu_elem)) {
17752 			aux = &env->insn_aux_data[i + delta];
17753 			if (bpf_map_ptr_poisoned(aux))
17754 				goto patch_call_imm;
17755 
17756 			map_ptr = BPF_MAP_PTR(aux->map_ptr_state);
17757 			ops = map_ptr->ops;
17758 			if (insn->imm == BPF_FUNC_map_lookup_elem &&
17759 			    ops->map_gen_lookup) {
17760 				cnt = ops->map_gen_lookup(map_ptr, insn_buf);
17761 				if (cnt == -EOPNOTSUPP)
17762 					goto patch_map_ops_generic;
17763 				if (cnt <= 0 || cnt >= ARRAY_SIZE(insn_buf)) {
17764 					verbose(env, "bpf verifier is misconfigured\n");
17765 					return -EINVAL;
17766 				}
17767 
17768 				new_prog = bpf_patch_insn_data(env, i + delta,
17769 							       insn_buf, cnt);
17770 				if (!new_prog)
17771 					return -ENOMEM;
17772 
17773 				delta    += cnt - 1;
17774 				env->prog = prog = new_prog;
17775 				insn      = new_prog->insnsi + i + delta;
17776 				continue;
17777 			}
17778 
17779 			BUILD_BUG_ON(!__same_type(ops->map_lookup_elem,
17780 				     (void *(*)(struct bpf_map *map, void *key))NULL));
17781 			BUILD_BUG_ON(!__same_type(ops->map_delete_elem,
17782 				     (long (*)(struct bpf_map *map, void *key))NULL));
17783 			BUILD_BUG_ON(!__same_type(ops->map_update_elem,
17784 				     (long (*)(struct bpf_map *map, void *key, void *value,
17785 					      u64 flags))NULL));
17786 			BUILD_BUG_ON(!__same_type(ops->map_push_elem,
17787 				     (long (*)(struct bpf_map *map, void *value,
17788 					      u64 flags))NULL));
17789 			BUILD_BUG_ON(!__same_type(ops->map_pop_elem,
17790 				     (long (*)(struct bpf_map *map, void *value))NULL));
17791 			BUILD_BUG_ON(!__same_type(ops->map_peek_elem,
17792 				     (long (*)(struct bpf_map *map, void *value))NULL));
17793 			BUILD_BUG_ON(!__same_type(ops->map_redirect,
17794 				     (long (*)(struct bpf_map *map, u64 index, u64 flags))NULL));
17795 			BUILD_BUG_ON(!__same_type(ops->map_for_each_callback,
17796 				     (long (*)(struct bpf_map *map,
17797 					      bpf_callback_t callback_fn,
17798 					      void *callback_ctx,
17799 					      u64 flags))NULL));
17800 			BUILD_BUG_ON(!__same_type(ops->map_lookup_percpu_elem,
17801 				     (void *(*)(struct bpf_map *map, void *key, u32 cpu))NULL));
17802 
17803 patch_map_ops_generic:
17804 			switch (insn->imm) {
17805 			case BPF_FUNC_map_lookup_elem:
17806 				insn->imm = BPF_CALL_IMM(ops->map_lookup_elem);
17807 				continue;
17808 			case BPF_FUNC_map_update_elem:
17809 				insn->imm = BPF_CALL_IMM(ops->map_update_elem);
17810 				continue;
17811 			case BPF_FUNC_map_delete_elem:
17812 				insn->imm = BPF_CALL_IMM(ops->map_delete_elem);
17813 				continue;
17814 			case BPF_FUNC_map_push_elem:
17815 				insn->imm = BPF_CALL_IMM(ops->map_push_elem);
17816 				continue;
17817 			case BPF_FUNC_map_pop_elem:
17818 				insn->imm = BPF_CALL_IMM(ops->map_pop_elem);
17819 				continue;
17820 			case BPF_FUNC_map_peek_elem:
17821 				insn->imm = BPF_CALL_IMM(ops->map_peek_elem);
17822 				continue;
17823 			case BPF_FUNC_redirect_map:
17824 				insn->imm = BPF_CALL_IMM(ops->map_redirect);
17825 				continue;
17826 			case BPF_FUNC_for_each_map_elem:
17827 				insn->imm = BPF_CALL_IMM(ops->map_for_each_callback);
17828 				continue;
17829 			case BPF_FUNC_map_lookup_percpu_elem:
17830 				insn->imm = BPF_CALL_IMM(ops->map_lookup_percpu_elem);
17831 				continue;
17832 			}
17833 
17834 			goto patch_call_imm;
17835 		}
17836 
17837 		/* Implement bpf_jiffies64 inline. */
17838 		if (prog->jit_requested && BITS_PER_LONG == 64 &&
17839 		    insn->imm == BPF_FUNC_jiffies64) {
17840 			struct bpf_insn ld_jiffies_addr[2] = {
17841 				BPF_LD_IMM64(BPF_REG_0,
17842 					     (unsigned long)&jiffies),
17843 			};
17844 
17845 			insn_buf[0] = ld_jiffies_addr[0];
17846 			insn_buf[1] = ld_jiffies_addr[1];
17847 			insn_buf[2] = BPF_LDX_MEM(BPF_DW, BPF_REG_0,
17848 						  BPF_REG_0, 0);
17849 			cnt = 3;
17850 
17851 			new_prog = bpf_patch_insn_data(env, i + delta, insn_buf,
17852 						       cnt);
17853 			if (!new_prog)
17854 				return -ENOMEM;
17855 
17856 			delta    += cnt - 1;
17857 			env->prog = prog = new_prog;
17858 			insn      = new_prog->insnsi + i + delta;
17859 			continue;
17860 		}
17861 
17862 		/* Implement bpf_get_func_arg inline. */
17863 		if (prog_type == BPF_PROG_TYPE_TRACING &&
17864 		    insn->imm == BPF_FUNC_get_func_arg) {
17865 			/* Load nr_args from ctx - 8 */
17866 			insn_buf[0] = BPF_LDX_MEM(BPF_DW, BPF_REG_0, BPF_REG_1, -8);
17867 			insn_buf[1] = BPF_JMP32_REG(BPF_JGE, BPF_REG_2, BPF_REG_0, 6);
17868 			insn_buf[2] = BPF_ALU64_IMM(BPF_LSH, BPF_REG_2, 3);
17869 			insn_buf[3] = BPF_ALU64_REG(BPF_ADD, BPF_REG_2, BPF_REG_1);
17870 			insn_buf[4] = BPF_LDX_MEM(BPF_DW, BPF_REG_0, BPF_REG_2, 0);
17871 			insn_buf[5] = BPF_STX_MEM(BPF_DW, BPF_REG_3, BPF_REG_0, 0);
17872 			insn_buf[6] = BPF_MOV64_IMM(BPF_REG_0, 0);
17873 			insn_buf[7] = BPF_JMP_A(1);
17874 			insn_buf[8] = BPF_MOV64_IMM(BPF_REG_0, -EINVAL);
17875 			cnt = 9;
17876 
17877 			new_prog = bpf_patch_insn_data(env, i + delta, insn_buf, cnt);
17878 			if (!new_prog)
17879 				return -ENOMEM;
17880 
17881 			delta    += cnt - 1;
17882 			env->prog = prog = new_prog;
17883 			insn      = new_prog->insnsi + i + delta;
17884 			continue;
17885 		}
17886 
17887 		/* Implement bpf_get_func_ret inline. */
17888 		if (prog_type == BPF_PROG_TYPE_TRACING &&
17889 		    insn->imm == BPF_FUNC_get_func_ret) {
17890 			if (eatype == BPF_TRACE_FEXIT ||
17891 			    eatype == BPF_MODIFY_RETURN) {
17892 				/* Load nr_args from ctx - 8 */
17893 				insn_buf[0] = BPF_LDX_MEM(BPF_DW, BPF_REG_0, BPF_REG_1, -8);
17894 				insn_buf[1] = BPF_ALU64_IMM(BPF_LSH, BPF_REG_0, 3);
17895 				insn_buf[2] = BPF_ALU64_REG(BPF_ADD, BPF_REG_0, BPF_REG_1);
17896 				insn_buf[3] = BPF_LDX_MEM(BPF_DW, BPF_REG_3, BPF_REG_0, 0);
17897 				insn_buf[4] = BPF_STX_MEM(BPF_DW, BPF_REG_2, BPF_REG_3, 0);
17898 				insn_buf[5] = BPF_MOV64_IMM(BPF_REG_0, 0);
17899 				cnt = 6;
17900 			} else {
17901 				insn_buf[0] = BPF_MOV64_IMM(BPF_REG_0, -EOPNOTSUPP);
17902 				cnt = 1;
17903 			}
17904 
17905 			new_prog = bpf_patch_insn_data(env, i + delta, insn_buf, cnt);
17906 			if (!new_prog)
17907 				return -ENOMEM;
17908 
17909 			delta    += cnt - 1;
17910 			env->prog = prog = new_prog;
17911 			insn      = new_prog->insnsi + i + delta;
17912 			continue;
17913 		}
17914 
17915 		/* Implement get_func_arg_cnt inline. */
17916 		if (prog_type == BPF_PROG_TYPE_TRACING &&
17917 		    insn->imm == BPF_FUNC_get_func_arg_cnt) {
17918 			/* Load nr_args from ctx - 8 */
17919 			insn_buf[0] = BPF_LDX_MEM(BPF_DW, BPF_REG_0, BPF_REG_1, -8);
17920 
17921 			new_prog = bpf_patch_insn_data(env, i + delta, insn_buf, 1);
17922 			if (!new_prog)
17923 				return -ENOMEM;
17924 
17925 			env->prog = prog = new_prog;
17926 			insn      = new_prog->insnsi + i + delta;
17927 			continue;
17928 		}
17929 
17930 		/* Implement bpf_get_func_ip inline. */
17931 		if (prog_type == BPF_PROG_TYPE_TRACING &&
17932 		    insn->imm == BPF_FUNC_get_func_ip) {
17933 			/* Load IP address from ctx - 16 */
17934 			insn_buf[0] = BPF_LDX_MEM(BPF_DW, BPF_REG_0, BPF_REG_1, -16);
17935 
17936 			new_prog = bpf_patch_insn_data(env, i + delta, insn_buf, 1);
17937 			if (!new_prog)
17938 				return -ENOMEM;
17939 
17940 			env->prog = prog = new_prog;
17941 			insn      = new_prog->insnsi + i + delta;
17942 			continue;
17943 		}
17944 
17945 patch_call_imm:
17946 		fn = env->ops->get_func_proto(insn->imm, env->prog);
17947 		/* all functions that have prototype and verifier allowed
17948 		 * programs to call them, must be real in-kernel functions
17949 		 */
17950 		if (!fn->func) {
17951 			verbose(env,
17952 				"kernel subsystem misconfigured func %s#%d\n",
17953 				func_id_name(insn->imm), insn->imm);
17954 			return -EFAULT;
17955 		}
17956 		insn->imm = fn->func - __bpf_call_base;
17957 	}
17958 
17959 	/* Since poke tab is now finalized, publish aux to tracker. */
17960 	for (i = 0; i < prog->aux->size_poke_tab; i++) {
17961 		map_ptr = prog->aux->poke_tab[i].tail_call.map;
17962 		if (!map_ptr->ops->map_poke_track ||
17963 		    !map_ptr->ops->map_poke_untrack ||
17964 		    !map_ptr->ops->map_poke_run) {
17965 			verbose(env, "bpf verifier is misconfigured\n");
17966 			return -EINVAL;
17967 		}
17968 
17969 		ret = map_ptr->ops->map_poke_track(map_ptr, prog->aux);
17970 		if (ret < 0) {
17971 			verbose(env, "tracking tail call prog failed\n");
17972 			return ret;
17973 		}
17974 	}
17975 
17976 	sort_kfunc_descs_by_imm_off(env->prog);
17977 
17978 	return 0;
17979 }
17980 
17981 static struct bpf_prog *inline_bpf_loop(struct bpf_verifier_env *env,
17982 					int position,
17983 					s32 stack_base,
17984 					u32 callback_subprogno,
17985 					u32 *cnt)
17986 {
17987 	s32 r6_offset = stack_base + 0 * BPF_REG_SIZE;
17988 	s32 r7_offset = stack_base + 1 * BPF_REG_SIZE;
17989 	s32 r8_offset = stack_base + 2 * BPF_REG_SIZE;
17990 	int reg_loop_max = BPF_REG_6;
17991 	int reg_loop_cnt = BPF_REG_7;
17992 	int reg_loop_ctx = BPF_REG_8;
17993 
17994 	struct bpf_prog *new_prog;
17995 	u32 callback_start;
17996 	u32 call_insn_offset;
17997 	s32 callback_offset;
17998 
17999 	/* This represents an inlined version of bpf_iter.c:bpf_loop,
18000 	 * be careful to modify this code in sync.
18001 	 */
18002 	struct bpf_insn insn_buf[] = {
18003 		/* Return error and jump to the end of the patch if
18004 		 * expected number of iterations is too big.
18005 		 */
18006 		BPF_JMP_IMM(BPF_JLE, BPF_REG_1, BPF_MAX_LOOPS, 2),
18007 		BPF_MOV32_IMM(BPF_REG_0, -E2BIG),
18008 		BPF_JMP_IMM(BPF_JA, 0, 0, 16),
18009 		/* spill R6, R7, R8 to use these as loop vars */
18010 		BPF_STX_MEM(BPF_DW, BPF_REG_10, BPF_REG_6, r6_offset),
18011 		BPF_STX_MEM(BPF_DW, BPF_REG_10, BPF_REG_7, r7_offset),
18012 		BPF_STX_MEM(BPF_DW, BPF_REG_10, BPF_REG_8, r8_offset),
18013 		/* initialize loop vars */
18014 		BPF_MOV64_REG(reg_loop_max, BPF_REG_1),
18015 		BPF_MOV32_IMM(reg_loop_cnt, 0),
18016 		BPF_MOV64_REG(reg_loop_ctx, BPF_REG_3),
18017 		/* loop header,
18018 		 * if reg_loop_cnt >= reg_loop_max skip the loop body
18019 		 */
18020 		BPF_JMP_REG(BPF_JGE, reg_loop_cnt, reg_loop_max, 5),
18021 		/* callback call,
18022 		 * correct callback offset would be set after patching
18023 		 */
18024 		BPF_MOV64_REG(BPF_REG_1, reg_loop_cnt),
18025 		BPF_MOV64_REG(BPF_REG_2, reg_loop_ctx),
18026 		BPF_CALL_REL(0),
18027 		/* increment loop counter */
18028 		BPF_ALU64_IMM(BPF_ADD, reg_loop_cnt, 1),
18029 		/* jump to loop header if callback returned 0 */
18030 		BPF_JMP_IMM(BPF_JEQ, BPF_REG_0, 0, -6),
18031 		/* return value of bpf_loop,
18032 		 * set R0 to the number of iterations
18033 		 */
18034 		BPF_MOV64_REG(BPF_REG_0, reg_loop_cnt),
18035 		/* restore original values of R6, R7, R8 */
18036 		BPF_LDX_MEM(BPF_DW, BPF_REG_6, BPF_REG_10, r6_offset),
18037 		BPF_LDX_MEM(BPF_DW, BPF_REG_7, BPF_REG_10, r7_offset),
18038 		BPF_LDX_MEM(BPF_DW, BPF_REG_8, BPF_REG_10, r8_offset),
18039 	};
18040 
18041 	*cnt = ARRAY_SIZE(insn_buf);
18042 	new_prog = bpf_patch_insn_data(env, position, insn_buf, *cnt);
18043 	if (!new_prog)
18044 		return new_prog;
18045 
18046 	/* callback start is known only after patching */
18047 	callback_start = env->subprog_info[callback_subprogno].start;
18048 	/* Note: insn_buf[12] is an offset of BPF_CALL_REL instruction */
18049 	call_insn_offset = position + 12;
18050 	callback_offset = callback_start - call_insn_offset - 1;
18051 	new_prog->insnsi[call_insn_offset].imm = callback_offset;
18052 
18053 	return new_prog;
18054 }
18055 
18056 static bool is_bpf_loop_call(struct bpf_insn *insn)
18057 {
18058 	return insn->code == (BPF_JMP | BPF_CALL) &&
18059 		insn->src_reg == 0 &&
18060 		insn->imm == BPF_FUNC_loop;
18061 }
18062 
18063 /* For all sub-programs in the program (including main) check
18064  * insn_aux_data to see if there are bpf_loop calls that require
18065  * inlining. If such calls are found the calls are replaced with a
18066  * sequence of instructions produced by `inline_bpf_loop` function and
18067  * subprog stack_depth is increased by the size of 3 registers.
18068  * This stack space is used to spill values of the R6, R7, R8.  These
18069  * registers are used to store the loop bound, counter and context
18070  * variables.
18071  */
18072 static int optimize_bpf_loop(struct bpf_verifier_env *env)
18073 {
18074 	struct bpf_subprog_info *subprogs = env->subprog_info;
18075 	int i, cur_subprog = 0, cnt, delta = 0;
18076 	struct bpf_insn *insn = env->prog->insnsi;
18077 	int insn_cnt = env->prog->len;
18078 	u16 stack_depth = subprogs[cur_subprog].stack_depth;
18079 	u16 stack_depth_roundup = round_up(stack_depth, 8) - stack_depth;
18080 	u16 stack_depth_extra = 0;
18081 
18082 	for (i = 0; i < insn_cnt; i++, insn++) {
18083 		struct bpf_loop_inline_state *inline_state =
18084 			&env->insn_aux_data[i + delta].loop_inline_state;
18085 
18086 		if (is_bpf_loop_call(insn) && inline_state->fit_for_inline) {
18087 			struct bpf_prog *new_prog;
18088 
18089 			stack_depth_extra = BPF_REG_SIZE * 3 + stack_depth_roundup;
18090 			new_prog = inline_bpf_loop(env,
18091 						   i + delta,
18092 						   -(stack_depth + stack_depth_extra),
18093 						   inline_state->callback_subprogno,
18094 						   &cnt);
18095 			if (!new_prog)
18096 				return -ENOMEM;
18097 
18098 			delta     += cnt - 1;
18099 			env->prog  = new_prog;
18100 			insn       = new_prog->insnsi + i + delta;
18101 		}
18102 
18103 		if (subprogs[cur_subprog + 1].start == i + delta + 1) {
18104 			subprogs[cur_subprog].stack_depth += stack_depth_extra;
18105 			cur_subprog++;
18106 			stack_depth = subprogs[cur_subprog].stack_depth;
18107 			stack_depth_roundup = round_up(stack_depth, 8) - stack_depth;
18108 			stack_depth_extra = 0;
18109 		}
18110 	}
18111 
18112 	env->prog->aux->stack_depth = env->subprog_info[0].stack_depth;
18113 
18114 	return 0;
18115 }
18116 
18117 static void free_states(struct bpf_verifier_env *env)
18118 {
18119 	struct bpf_verifier_state_list *sl, *sln;
18120 	int i;
18121 
18122 	sl = env->free_list;
18123 	while (sl) {
18124 		sln = sl->next;
18125 		free_verifier_state(&sl->state, false);
18126 		kfree(sl);
18127 		sl = sln;
18128 	}
18129 	env->free_list = NULL;
18130 
18131 	if (!env->explored_states)
18132 		return;
18133 
18134 	for (i = 0; i < state_htab_size(env); i++) {
18135 		sl = env->explored_states[i];
18136 
18137 		while (sl) {
18138 			sln = sl->next;
18139 			free_verifier_state(&sl->state, false);
18140 			kfree(sl);
18141 			sl = sln;
18142 		}
18143 		env->explored_states[i] = NULL;
18144 	}
18145 }
18146 
18147 static int do_check_common(struct bpf_verifier_env *env, int subprog)
18148 {
18149 	bool pop_log = !(env->log.level & BPF_LOG_LEVEL2);
18150 	struct bpf_verifier_state *state;
18151 	struct bpf_reg_state *regs;
18152 	int ret, i;
18153 
18154 	env->prev_linfo = NULL;
18155 	env->pass_cnt++;
18156 
18157 	state = kzalloc(sizeof(struct bpf_verifier_state), GFP_KERNEL);
18158 	if (!state)
18159 		return -ENOMEM;
18160 	state->curframe = 0;
18161 	state->speculative = false;
18162 	state->branches = 1;
18163 	state->frame[0] = kzalloc(sizeof(struct bpf_func_state), GFP_KERNEL);
18164 	if (!state->frame[0]) {
18165 		kfree(state);
18166 		return -ENOMEM;
18167 	}
18168 	env->cur_state = state;
18169 	init_func_state(env, state->frame[0],
18170 			BPF_MAIN_FUNC /* callsite */,
18171 			0 /* frameno */,
18172 			subprog);
18173 	state->first_insn_idx = env->subprog_info[subprog].start;
18174 	state->last_insn_idx = -1;
18175 
18176 	regs = state->frame[state->curframe]->regs;
18177 	if (subprog || env->prog->type == BPF_PROG_TYPE_EXT) {
18178 		ret = btf_prepare_func_args(env, subprog, regs);
18179 		if (ret)
18180 			goto out;
18181 		for (i = BPF_REG_1; i <= BPF_REG_5; i++) {
18182 			if (regs[i].type == PTR_TO_CTX)
18183 				mark_reg_known_zero(env, regs, i);
18184 			else if (regs[i].type == SCALAR_VALUE)
18185 				mark_reg_unknown(env, regs, i);
18186 			else if (base_type(regs[i].type) == PTR_TO_MEM) {
18187 				const u32 mem_size = regs[i].mem_size;
18188 
18189 				mark_reg_known_zero(env, regs, i);
18190 				regs[i].mem_size = mem_size;
18191 				regs[i].id = ++env->id_gen;
18192 			}
18193 		}
18194 	} else {
18195 		/* 1st arg to a function */
18196 		regs[BPF_REG_1].type = PTR_TO_CTX;
18197 		mark_reg_known_zero(env, regs, BPF_REG_1);
18198 		ret = btf_check_subprog_arg_match(env, subprog, regs);
18199 		if (ret == -EFAULT)
18200 			/* unlikely verifier bug. abort.
18201 			 * ret == 0 and ret < 0 are sadly acceptable for
18202 			 * main() function due to backward compatibility.
18203 			 * Like socket filter program may be written as:
18204 			 * int bpf_prog(struct pt_regs *ctx)
18205 			 * and never dereference that ctx in the program.
18206 			 * 'struct pt_regs' is a type mismatch for socket
18207 			 * filter that should be using 'struct __sk_buff'.
18208 			 */
18209 			goto out;
18210 	}
18211 
18212 	ret = do_check(env);
18213 out:
18214 	/* check for NULL is necessary, since cur_state can be freed inside
18215 	 * do_check() under memory pressure.
18216 	 */
18217 	if (env->cur_state) {
18218 		free_verifier_state(env->cur_state, true);
18219 		env->cur_state = NULL;
18220 	}
18221 	while (!pop_stack(env, NULL, NULL, false));
18222 	if (!ret && pop_log)
18223 		bpf_vlog_reset(&env->log, 0);
18224 	free_states(env);
18225 	return ret;
18226 }
18227 
18228 /* Verify all global functions in a BPF program one by one based on their BTF.
18229  * All global functions must pass verification. Otherwise the whole program is rejected.
18230  * Consider:
18231  * int bar(int);
18232  * int foo(int f)
18233  * {
18234  *    return bar(f);
18235  * }
18236  * int bar(int b)
18237  * {
18238  *    ...
18239  * }
18240  * foo() will be verified first for R1=any_scalar_value. During verification it
18241  * will be assumed that bar() already verified successfully and call to bar()
18242  * from foo() will be checked for type match only. Later bar() will be verified
18243  * independently to check that it's safe for R1=any_scalar_value.
18244  */
18245 static int do_check_subprogs(struct bpf_verifier_env *env)
18246 {
18247 	struct bpf_prog_aux *aux = env->prog->aux;
18248 	int i, ret;
18249 
18250 	if (!aux->func_info)
18251 		return 0;
18252 
18253 	for (i = 1; i < env->subprog_cnt; i++) {
18254 		if (aux->func_info_aux[i].linkage != BTF_FUNC_GLOBAL)
18255 			continue;
18256 		env->insn_idx = env->subprog_info[i].start;
18257 		WARN_ON_ONCE(env->insn_idx == 0);
18258 		ret = do_check_common(env, i);
18259 		if (ret) {
18260 			return ret;
18261 		} else if (env->log.level & BPF_LOG_LEVEL) {
18262 			verbose(env,
18263 				"Func#%d is safe for any args that match its prototype\n",
18264 				i);
18265 		}
18266 	}
18267 	return 0;
18268 }
18269 
18270 static int do_check_main(struct bpf_verifier_env *env)
18271 {
18272 	int ret;
18273 
18274 	env->insn_idx = 0;
18275 	ret = do_check_common(env, 0);
18276 	if (!ret)
18277 		env->prog->aux->stack_depth = env->subprog_info[0].stack_depth;
18278 	return ret;
18279 }
18280 
18281 
18282 static void print_verification_stats(struct bpf_verifier_env *env)
18283 {
18284 	int i;
18285 
18286 	if (env->log.level & BPF_LOG_STATS) {
18287 		verbose(env, "verification time %lld usec\n",
18288 			div_u64(env->verification_time, 1000));
18289 		verbose(env, "stack depth ");
18290 		for (i = 0; i < env->subprog_cnt; i++) {
18291 			u32 depth = env->subprog_info[i].stack_depth;
18292 
18293 			verbose(env, "%d", depth);
18294 			if (i + 1 < env->subprog_cnt)
18295 				verbose(env, "+");
18296 		}
18297 		verbose(env, "\n");
18298 	}
18299 	verbose(env, "processed %d insns (limit %d) max_states_per_insn %d "
18300 		"total_states %d peak_states %d mark_read %d\n",
18301 		env->insn_processed, BPF_COMPLEXITY_LIMIT_INSNS,
18302 		env->max_states_per_insn, env->total_states,
18303 		env->peak_states, env->longest_mark_read_walk);
18304 }
18305 
18306 static int check_struct_ops_btf_id(struct bpf_verifier_env *env)
18307 {
18308 	const struct btf_type *t, *func_proto;
18309 	const struct bpf_struct_ops *st_ops;
18310 	const struct btf_member *member;
18311 	struct bpf_prog *prog = env->prog;
18312 	u32 btf_id, member_idx;
18313 	const char *mname;
18314 
18315 	if (!prog->gpl_compatible) {
18316 		verbose(env, "struct ops programs must have a GPL compatible license\n");
18317 		return -EINVAL;
18318 	}
18319 
18320 	btf_id = prog->aux->attach_btf_id;
18321 	st_ops = bpf_struct_ops_find(btf_id);
18322 	if (!st_ops) {
18323 		verbose(env, "attach_btf_id %u is not a supported struct\n",
18324 			btf_id);
18325 		return -ENOTSUPP;
18326 	}
18327 
18328 	t = st_ops->type;
18329 	member_idx = prog->expected_attach_type;
18330 	if (member_idx >= btf_type_vlen(t)) {
18331 		verbose(env, "attach to invalid member idx %u of struct %s\n",
18332 			member_idx, st_ops->name);
18333 		return -EINVAL;
18334 	}
18335 
18336 	member = &btf_type_member(t)[member_idx];
18337 	mname = btf_name_by_offset(btf_vmlinux, member->name_off);
18338 	func_proto = btf_type_resolve_func_ptr(btf_vmlinux, member->type,
18339 					       NULL);
18340 	if (!func_proto) {
18341 		verbose(env, "attach to invalid member %s(@idx %u) of struct %s\n",
18342 			mname, member_idx, st_ops->name);
18343 		return -EINVAL;
18344 	}
18345 
18346 	if (st_ops->check_member) {
18347 		int err = st_ops->check_member(t, member, prog);
18348 
18349 		if (err) {
18350 			verbose(env, "attach to unsupported member %s of struct %s\n",
18351 				mname, st_ops->name);
18352 			return err;
18353 		}
18354 	}
18355 
18356 	prog->aux->attach_func_proto = func_proto;
18357 	prog->aux->attach_func_name = mname;
18358 	env->ops = st_ops->verifier_ops;
18359 
18360 	return 0;
18361 }
18362 #define SECURITY_PREFIX "security_"
18363 
18364 static int check_attach_modify_return(unsigned long addr, const char *func_name)
18365 {
18366 	if (within_error_injection_list(addr) ||
18367 	    !strncmp(SECURITY_PREFIX, func_name, sizeof(SECURITY_PREFIX) - 1))
18368 		return 0;
18369 
18370 	return -EINVAL;
18371 }
18372 
18373 /* list of non-sleepable functions that are otherwise on
18374  * ALLOW_ERROR_INJECTION list
18375  */
18376 BTF_SET_START(btf_non_sleepable_error_inject)
18377 /* Three functions below can be called from sleepable and non-sleepable context.
18378  * Assume non-sleepable from bpf safety point of view.
18379  */
18380 BTF_ID(func, __filemap_add_folio)
18381 BTF_ID(func, should_fail_alloc_page)
18382 BTF_ID(func, should_failslab)
18383 BTF_SET_END(btf_non_sleepable_error_inject)
18384 
18385 static int check_non_sleepable_error_inject(u32 btf_id)
18386 {
18387 	return btf_id_set_contains(&btf_non_sleepable_error_inject, btf_id);
18388 }
18389 
18390 int bpf_check_attach_target(struct bpf_verifier_log *log,
18391 			    const struct bpf_prog *prog,
18392 			    const struct bpf_prog *tgt_prog,
18393 			    u32 btf_id,
18394 			    struct bpf_attach_target_info *tgt_info)
18395 {
18396 	bool prog_extension = prog->type == BPF_PROG_TYPE_EXT;
18397 	const char prefix[] = "btf_trace_";
18398 	int ret = 0, subprog = -1, i;
18399 	const struct btf_type *t;
18400 	bool conservative = true;
18401 	const char *tname;
18402 	struct btf *btf;
18403 	long addr = 0;
18404 	struct module *mod = NULL;
18405 
18406 	if (!btf_id) {
18407 		bpf_log(log, "Tracing programs must provide btf_id\n");
18408 		return -EINVAL;
18409 	}
18410 	btf = tgt_prog ? tgt_prog->aux->btf : prog->aux->attach_btf;
18411 	if (!btf) {
18412 		bpf_log(log,
18413 			"FENTRY/FEXIT program can only be attached to another program annotated with BTF\n");
18414 		return -EINVAL;
18415 	}
18416 	t = btf_type_by_id(btf, btf_id);
18417 	if (!t) {
18418 		bpf_log(log, "attach_btf_id %u is invalid\n", btf_id);
18419 		return -EINVAL;
18420 	}
18421 	tname = btf_name_by_offset(btf, t->name_off);
18422 	if (!tname) {
18423 		bpf_log(log, "attach_btf_id %u doesn't have a name\n", btf_id);
18424 		return -EINVAL;
18425 	}
18426 	if (tgt_prog) {
18427 		struct bpf_prog_aux *aux = tgt_prog->aux;
18428 
18429 		if (bpf_prog_is_dev_bound(prog->aux) &&
18430 		    !bpf_prog_dev_bound_match(prog, tgt_prog)) {
18431 			bpf_log(log, "Target program bound device mismatch");
18432 			return -EINVAL;
18433 		}
18434 
18435 		for (i = 0; i < aux->func_info_cnt; i++)
18436 			if (aux->func_info[i].type_id == btf_id) {
18437 				subprog = i;
18438 				break;
18439 			}
18440 		if (subprog == -1) {
18441 			bpf_log(log, "Subprog %s doesn't exist\n", tname);
18442 			return -EINVAL;
18443 		}
18444 		conservative = aux->func_info_aux[subprog].unreliable;
18445 		if (prog_extension) {
18446 			if (conservative) {
18447 				bpf_log(log,
18448 					"Cannot replace static functions\n");
18449 				return -EINVAL;
18450 			}
18451 			if (!prog->jit_requested) {
18452 				bpf_log(log,
18453 					"Extension programs should be JITed\n");
18454 				return -EINVAL;
18455 			}
18456 		}
18457 		if (!tgt_prog->jited) {
18458 			bpf_log(log, "Can attach to only JITed progs\n");
18459 			return -EINVAL;
18460 		}
18461 		if (tgt_prog->type == prog->type) {
18462 			/* Cannot fentry/fexit another fentry/fexit program.
18463 			 * Cannot attach program extension to another extension.
18464 			 * It's ok to attach fentry/fexit to extension program.
18465 			 */
18466 			bpf_log(log, "Cannot recursively attach\n");
18467 			return -EINVAL;
18468 		}
18469 		if (tgt_prog->type == BPF_PROG_TYPE_TRACING &&
18470 		    prog_extension &&
18471 		    (tgt_prog->expected_attach_type == BPF_TRACE_FENTRY ||
18472 		     tgt_prog->expected_attach_type == BPF_TRACE_FEXIT)) {
18473 			/* Program extensions can extend all program types
18474 			 * except fentry/fexit. The reason is the following.
18475 			 * The fentry/fexit programs are used for performance
18476 			 * analysis, stats and can be attached to any program
18477 			 * type except themselves. When extension program is
18478 			 * replacing XDP function it is necessary to allow
18479 			 * performance analysis of all functions. Both original
18480 			 * XDP program and its program extension. Hence
18481 			 * attaching fentry/fexit to BPF_PROG_TYPE_EXT is
18482 			 * allowed. If extending of fentry/fexit was allowed it
18483 			 * would be possible to create long call chain
18484 			 * fentry->extension->fentry->extension beyond
18485 			 * reasonable stack size. Hence extending fentry is not
18486 			 * allowed.
18487 			 */
18488 			bpf_log(log, "Cannot extend fentry/fexit\n");
18489 			return -EINVAL;
18490 		}
18491 	} else {
18492 		if (prog_extension) {
18493 			bpf_log(log, "Cannot replace kernel functions\n");
18494 			return -EINVAL;
18495 		}
18496 	}
18497 
18498 	switch (prog->expected_attach_type) {
18499 	case BPF_TRACE_RAW_TP:
18500 		if (tgt_prog) {
18501 			bpf_log(log,
18502 				"Only FENTRY/FEXIT progs are attachable to another BPF prog\n");
18503 			return -EINVAL;
18504 		}
18505 		if (!btf_type_is_typedef(t)) {
18506 			bpf_log(log, "attach_btf_id %u is not a typedef\n",
18507 				btf_id);
18508 			return -EINVAL;
18509 		}
18510 		if (strncmp(prefix, tname, sizeof(prefix) - 1)) {
18511 			bpf_log(log, "attach_btf_id %u points to wrong type name %s\n",
18512 				btf_id, tname);
18513 			return -EINVAL;
18514 		}
18515 		tname += sizeof(prefix) - 1;
18516 		t = btf_type_by_id(btf, t->type);
18517 		if (!btf_type_is_ptr(t))
18518 			/* should never happen in valid vmlinux build */
18519 			return -EINVAL;
18520 		t = btf_type_by_id(btf, t->type);
18521 		if (!btf_type_is_func_proto(t))
18522 			/* should never happen in valid vmlinux build */
18523 			return -EINVAL;
18524 
18525 		break;
18526 	case BPF_TRACE_ITER:
18527 		if (!btf_type_is_func(t)) {
18528 			bpf_log(log, "attach_btf_id %u is not a function\n",
18529 				btf_id);
18530 			return -EINVAL;
18531 		}
18532 		t = btf_type_by_id(btf, t->type);
18533 		if (!btf_type_is_func_proto(t))
18534 			return -EINVAL;
18535 		ret = btf_distill_func_proto(log, btf, t, tname, &tgt_info->fmodel);
18536 		if (ret)
18537 			return ret;
18538 		break;
18539 	default:
18540 		if (!prog_extension)
18541 			return -EINVAL;
18542 		fallthrough;
18543 	case BPF_MODIFY_RETURN:
18544 	case BPF_LSM_MAC:
18545 	case BPF_LSM_CGROUP:
18546 	case BPF_TRACE_FENTRY:
18547 	case BPF_TRACE_FEXIT:
18548 		if (!btf_type_is_func(t)) {
18549 			bpf_log(log, "attach_btf_id %u is not a function\n",
18550 				btf_id);
18551 			return -EINVAL;
18552 		}
18553 		if (prog_extension &&
18554 		    btf_check_type_match(log, prog, btf, t))
18555 			return -EINVAL;
18556 		t = btf_type_by_id(btf, t->type);
18557 		if (!btf_type_is_func_proto(t))
18558 			return -EINVAL;
18559 
18560 		if ((prog->aux->saved_dst_prog_type || prog->aux->saved_dst_attach_type) &&
18561 		    (!tgt_prog || prog->aux->saved_dst_prog_type != tgt_prog->type ||
18562 		     prog->aux->saved_dst_attach_type != tgt_prog->expected_attach_type))
18563 			return -EINVAL;
18564 
18565 		if (tgt_prog && conservative)
18566 			t = NULL;
18567 
18568 		ret = btf_distill_func_proto(log, btf, t, tname, &tgt_info->fmodel);
18569 		if (ret < 0)
18570 			return ret;
18571 
18572 		if (tgt_prog) {
18573 			if (subprog == 0)
18574 				addr = (long) tgt_prog->bpf_func;
18575 			else
18576 				addr = (long) tgt_prog->aux->func[subprog]->bpf_func;
18577 		} else {
18578 			if (btf_is_module(btf)) {
18579 				mod = btf_try_get_module(btf);
18580 				if (mod)
18581 					addr = find_kallsyms_symbol_value(mod, tname);
18582 				else
18583 					addr = 0;
18584 			} else {
18585 				addr = kallsyms_lookup_name(tname);
18586 			}
18587 			if (!addr) {
18588 				module_put(mod);
18589 				bpf_log(log,
18590 					"The address of function %s cannot be found\n",
18591 					tname);
18592 				return -ENOENT;
18593 			}
18594 		}
18595 
18596 		if (prog->aux->sleepable) {
18597 			ret = -EINVAL;
18598 			switch (prog->type) {
18599 			case BPF_PROG_TYPE_TRACING:
18600 
18601 				/* fentry/fexit/fmod_ret progs can be sleepable if they are
18602 				 * attached to ALLOW_ERROR_INJECTION and are not in denylist.
18603 				 */
18604 				if (!check_non_sleepable_error_inject(btf_id) &&
18605 				    within_error_injection_list(addr))
18606 					ret = 0;
18607 				/* fentry/fexit/fmod_ret progs can also be sleepable if they are
18608 				 * in the fmodret id set with the KF_SLEEPABLE flag.
18609 				 */
18610 				else {
18611 					u32 *flags = btf_kfunc_is_modify_return(btf, btf_id);
18612 
18613 					if (flags && (*flags & KF_SLEEPABLE))
18614 						ret = 0;
18615 				}
18616 				break;
18617 			case BPF_PROG_TYPE_LSM:
18618 				/* LSM progs check that they are attached to bpf_lsm_*() funcs.
18619 				 * Only some of them are sleepable.
18620 				 */
18621 				if (bpf_lsm_is_sleepable_hook(btf_id))
18622 					ret = 0;
18623 				break;
18624 			default:
18625 				break;
18626 			}
18627 			if (ret) {
18628 				module_put(mod);
18629 				bpf_log(log, "%s is not sleepable\n", tname);
18630 				return ret;
18631 			}
18632 		} else if (prog->expected_attach_type == BPF_MODIFY_RETURN) {
18633 			if (tgt_prog) {
18634 				module_put(mod);
18635 				bpf_log(log, "can't modify return codes of BPF programs\n");
18636 				return -EINVAL;
18637 			}
18638 			ret = -EINVAL;
18639 			if (btf_kfunc_is_modify_return(btf, btf_id) ||
18640 			    !check_attach_modify_return(addr, tname))
18641 				ret = 0;
18642 			if (ret) {
18643 				module_put(mod);
18644 				bpf_log(log, "%s() is not modifiable\n", tname);
18645 				return ret;
18646 			}
18647 		}
18648 
18649 		break;
18650 	}
18651 	tgt_info->tgt_addr = addr;
18652 	tgt_info->tgt_name = tname;
18653 	tgt_info->tgt_type = t;
18654 	tgt_info->tgt_mod = mod;
18655 	return 0;
18656 }
18657 
18658 BTF_SET_START(btf_id_deny)
18659 BTF_ID_UNUSED
18660 #ifdef CONFIG_SMP
18661 BTF_ID(func, migrate_disable)
18662 BTF_ID(func, migrate_enable)
18663 #endif
18664 #if !defined CONFIG_PREEMPT_RCU && !defined CONFIG_TINY_RCU
18665 BTF_ID(func, rcu_read_unlock_strict)
18666 #endif
18667 #if defined(CONFIG_DEBUG_PREEMPT) || defined(CONFIG_TRACE_PREEMPT_TOGGLE)
18668 BTF_ID(func, preempt_count_add)
18669 BTF_ID(func, preempt_count_sub)
18670 #endif
18671 BTF_SET_END(btf_id_deny)
18672 
18673 static bool can_be_sleepable(struct bpf_prog *prog)
18674 {
18675 	if (prog->type == BPF_PROG_TYPE_TRACING) {
18676 		switch (prog->expected_attach_type) {
18677 		case BPF_TRACE_FENTRY:
18678 		case BPF_TRACE_FEXIT:
18679 		case BPF_MODIFY_RETURN:
18680 		case BPF_TRACE_ITER:
18681 			return true;
18682 		default:
18683 			return false;
18684 		}
18685 	}
18686 	return prog->type == BPF_PROG_TYPE_LSM ||
18687 	       prog->type == BPF_PROG_TYPE_KPROBE /* only for uprobes */ ||
18688 	       prog->type == BPF_PROG_TYPE_STRUCT_OPS;
18689 }
18690 
18691 static int check_attach_btf_id(struct bpf_verifier_env *env)
18692 {
18693 	struct bpf_prog *prog = env->prog;
18694 	struct bpf_prog *tgt_prog = prog->aux->dst_prog;
18695 	struct bpf_attach_target_info tgt_info = {};
18696 	u32 btf_id = prog->aux->attach_btf_id;
18697 	struct bpf_trampoline *tr;
18698 	int ret;
18699 	u64 key;
18700 
18701 	if (prog->type == BPF_PROG_TYPE_SYSCALL) {
18702 		if (prog->aux->sleepable)
18703 			/* attach_btf_id checked to be zero already */
18704 			return 0;
18705 		verbose(env, "Syscall programs can only be sleepable\n");
18706 		return -EINVAL;
18707 	}
18708 
18709 	if (prog->aux->sleepable && !can_be_sleepable(prog)) {
18710 		verbose(env, "Only fentry/fexit/fmod_ret, lsm, iter, uprobe, and struct_ops programs can be sleepable\n");
18711 		return -EINVAL;
18712 	}
18713 
18714 	if (prog->type == BPF_PROG_TYPE_STRUCT_OPS)
18715 		return check_struct_ops_btf_id(env);
18716 
18717 	if (prog->type != BPF_PROG_TYPE_TRACING &&
18718 	    prog->type != BPF_PROG_TYPE_LSM &&
18719 	    prog->type != BPF_PROG_TYPE_EXT)
18720 		return 0;
18721 
18722 	ret = bpf_check_attach_target(&env->log, prog, tgt_prog, btf_id, &tgt_info);
18723 	if (ret)
18724 		return ret;
18725 
18726 	if (tgt_prog && prog->type == BPF_PROG_TYPE_EXT) {
18727 		/* to make freplace equivalent to their targets, they need to
18728 		 * inherit env->ops and expected_attach_type for the rest of the
18729 		 * verification
18730 		 */
18731 		env->ops = bpf_verifier_ops[tgt_prog->type];
18732 		prog->expected_attach_type = tgt_prog->expected_attach_type;
18733 	}
18734 
18735 	/* store info about the attachment target that will be used later */
18736 	prog->aux->attach_func_proto = tgt_info.tgt_type;
18737 	prog->aux->attach_func_name = tgt_info.tgt_name;
18738 	prog->aux->mod = tgt_info.tgt_mod;
18739 
18740 	if (tgt_prog) {
18741 		prog->aux->saved_dst_prog_type = tgt_prog->type;
18742 		prog->aux->saved_dst_attach_type = tgt_prog->expected_attach_type;
18743 	}
18744 
18745 	if (prog->expected_attach_type == BPF_TRACE_RAW_TP) {
18746 		prog->aux->attach_btf_trace = true;
18747 		return 0;
18748 	} else if (prog->expected_attach_type == BPF_TRACE_ITER) {
18749 		if (!bpf_iter_prog_supported(prog))
18750 			return -EINVAL;
18751 		return 0;
18752 	}
18753 
18754 	if (prog->type == BPF_PROG_TYPE_LSM) {
18755 		ret = bpf_lsm_verify_prog(&env->log, prog);
18756 		if (ret < 0)
18757 			return ret;
18758 	} else if (prog->type == BPF_PROG_TYPE_TRACING &&
18759 		   btf_id_set_contains(&btf_id_deny, btf_id)) {
18760 		return -EINVAL;
18761 	}
18762 
18763 	key = bpf_trampoline_compute_key(tgt_prog, prog->aux->attach_btf, btf_id);
18764 	tr = bpf_trampoline_get(key, &tgt_info);
18765 	if (!tr)
18766 		return -ENOMEM;
18767 
18768 	prog->aux->dst_trampoline = tr;
18769 	return 0;
18770 }
18771 
18772 struct btf *bpf_get_btf_vmlinux(void)
18773 {
18774 	if (!btf_vmlinux && IS_ENABLED(CONFIG_DEBUG_INFO_BTF)) {
18775 		mutex_lock(&bpf_verifier_lock);
18776 		if (!btf_vmlinux)
18777 			btf_vmlinux = btf_parse_vmlinux();
18778 		mutex_unlock(&bpf_verifier_lock);
18779 	}
18780 	return btf_vmlinux;
18781 }
18782 
18783 int bpf_check(struct bpf_prog **prog, union bpf_attr *attr, bpfptr_t uattr, __u32 uattr_size)
18784 {
18785 	u64 start_time = ktime_get_ns();
18786 	struct bpf_verifier_env *env;
18787 	int i, len, ret = -EINVAL, err;
18788 	u32 log_true_size;
18789 	bool is_priv;
18790 
18791 	/* no program is valid */
18792 	if (ARRAY_SIZE(bpf_verifier_ops) == 0)
18793 		return -EINVAL;
18794 
18795 	/* 'struct bpf_verifier_env' can be global, but since it's not small,
18796 	 * allocate/free it every time bpf_check() is called
18797 	 */
18798 	env = kzalloc(sizeof(struct bpf_verifier_env), GFP_KERNEL);
18799 	if (!env)
18800 		return -ENOMEM;
18801 
18802 	len = (*prog)->len;
18803 	env->insn_aux_data =
18804 		vzalloc(array_size(sizeof(struct bpf_insn_aux_data), len));
18805 	ret = -ENOMEM;
18806 	if (!env->insn_aux_data)
18807 		goto err_free_env;
18808 	for (i = 0; i < len; i++)
18809 		env->insn_aux_data[i].orig_idx = i;
18810 	env->prog = *prog;
18811 	env->ops = bpf_verifier_ops[env->prog->type];
18812 	env->fd_array = make_bpfptr(attr->fd_array, uattr.is_kernel);
18813 	is_priv = bpf_capable();
18814 
18815 	bpf_get_btf_vmlinux();
18816 
18817 	/* grab the mutex to protect few globals used by verifier */
18818 	if (!is_priv)
18819 		mutex_lock(&bpf_verifier_lock);
18820 
18821 	/* user could have requested verbose verifier output
18822 	 * and supplied buffer to store the verification trace
18823 	 */
18824 	ret = bpf_vlog_init(&env->log, attr->log_level,
18825 			    (char __user *) (unsigned long) attr->log_buf,
18826 			    attr->log_size);
18827 	if (ret)
18828 		goto err_unlock;
18829 
18830 	mark_verifier_state_clean(env);
18831 
18832 	if (IS_ERR(btf_vmlinux)) {
18833 		/* Either gcc or pahole or kernel are broken. */
18834 		verbose(env, "in-kernel BTF is malformed\n");
18835 		ret = PTR_ERR(btf_vmlinux);
18836 		goto skip_full_check;
18837 	}
18838 
18839 	env->strict_alignment = !!(attr->prog_flags & BPF_F_STRICT_ALIGNMENT);
18840 	if (!IS_ENABLED(CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS))
18841 		env->strict_alignment = true;
18842 	if (attr->prog_flags & BPF_F_ANY_ALIGNMENT)
18843 		env->strict_alignment = false;
18844 
18845 	env->allow_ptr_leaks = bpf_allow_ptr_leaks();
18846 	env->allow_uninit_stack = bpf_allow_uninit_stack();
18847 	env->bypass_spec_v1 = bpf_bypass_spec_v1();
18848 	env->bypass_spec_v4 = bpf_bypass_spec_v4();
18849 	env->bpf_capable = bpf_capable();
18850 
18851 	if (is_priv)
18852 		env->test_state_freq = attr->prog_flags & BPF_F_TEST_STATE_FREQ;
18853 
18854 	env->explored_states = kvcalloc(state_htab_size(env),
18855 				       sizeof(struct bpf_verifier_state_list *),
18856 				       GFP_USER);
18857 	ret = -ENOMEM;
18858 	if (!env->explored_states)
18859 		goto skip_full_check;
18860 
18861 	ret = add_subprog_and_kfunc(env);
18862 	if (ret < 0)
18863 		goto skip_full_check;
18864 
18865 	ret = check_subprogs(env);
18866 	if (ret < 0)
18867 		goto skip_full_check;
18868 
18869 	ret = check_btf_info(env, attr, uattr);
18870 	if (ret < 0)
18871 		goto skip_full_check;
18872 
18873 	ret = check_attach_btf_id(env);
18874 	if (ret)
18875 		goto skip_full_check;
18876 
18877 	ret = resolve_pseudo_ldimm64(env);
18878 	if (ret < 0)
18879 		goto skip_full_check;
18880 
18881 	if (bpf_prog_is_offloaded(env->prog->aux)) {
18882 		ret = bpf_prog_offload_verifier_prep(env->prog);
18883 		if (ret)
18884 			goto skip_full_check;
18885 	}
18886 
18887 	ret = check_cfg(env);
18888 	if (ret < 0)
18889 		goto skip_full_check;
18890 
18891 	ret = do_check_subprogs(env);
18892 	ret = ret ?: do_check_main(env);
18893 
18894 	if (ret == 0 && bpf_prog_is_offloaded(env->prog->aux))
18895 		ret = bpf_prog_offload_finalize(env);
18896 
18897 skip_full_check:
18898 	kvfree(env->explored_states);
18899 
18900 	if (ret == 0)
18901 		ret = check_max_stack_depth(env);
18902 
18903 	/* instruction rewrites happen after this point */
18904 	if (ret == 0)
18905 		ret = optimize_bpf_loop(env);
18906 
18907 	if (is_priv) {
18908 		if (ret == 0)
18909 			opt_hard_wire_dead_code_branches(env);
18910 		if (ret == 0)
18911 			ret = opt_remove_dead_code(env);
18912 		if (ret == 0)
18913 			ret = opt_remove_nops(env);
18914 	} else {
18915 		if (ret == 0)
18916 			sanitize_dead_code(env);
18917 	}
18918 
18919 	if (ret == 0)
18920 		/* program is valid, convert *(u32*)(ctx + off) accesses */
18921 		ret = convert_ctx_accesses(env);
18922 
18923 	if (ret == 0)
18924 		ret = do_misc_fixups(env);
18925 
18926 	/* do 32-bit optimization after insn patching has done so those patched
18927 	 * insns could be handled correctly.
18928 	 */
18929 	if (ret == 0 && !bpf_prog_is_offloaded(env->prog->aux)) {
18930 		ret = opt_subreg_zext_lo32_rnd_hi32(env, attr);
18931 		env->prog->aux->verifier_zext = bpf_jit_needs_zext() ? !ret
18932 								     : false;
18933 	}
18934 
18935 	if (ret == 0)
18936 		ret = fixup_call_args(env);
18937 
18938 	env->verification_time = ktime_get_ns() - start_time;
18939 	print_verification_stats(env);
18940 	env->prog->aux->verified_insns = env->insn_processed;
18941 
18942 	/* preserve original error even if log finalization is successful */
18943 	err = bpf_vlog_finalize(&env->log, &log_true_size);
18944 	if (err)
18945 		ret = err;
18946 
18947 	if (uattr_size >= offsetofend(union bpf_attr, log_true_size) &&
18948 	    copy_to_bpfptr_offset(uattr, offsetof(union bpf_attr, log_true_size),
18949 				  &log_true_size, sizeof(log_true_size))) {
18950 		ret = -EFAULT;
18951 		goto err_release_maps;
18952 	}
18953 
18954 	if (ret)
18955 		goto err_release_maps;
18956 
18957 	if (env->used_map_cnt) {
18958 		/* if program passed verifier, update used_maps in bpf_prog_info */
18959 		env->prog->aux->used_maps = kmalloc_array(env->used_map_cnt,
18960 							  sizeof(env->used_maps[0]),
18961 							  GFP_KERNEL);
18962 
18963 		if (!env->prog->aux->used_maps) {
18964 			ret = -ENOMEM;
18965 			goto err_release_maps;
18966 		}
18967 
18968 		memcpy(env->prog->aux->used_maps, env->used_maps,
18969 		       sizeof(env->used_maps[0]) * env->used_map_cnt);
18970 		env->prog->aux->used_map_cnt = env->used_map_cnt;
18971 	}
18972 	if (env->used_btf_cnt) {
18973 		/* if program passed verifier, update used_btfs in bpf_prog_aux */
18974 		env->prog->aux->used_btfs = kmalloc_array(env->used_btf_cnt,
18975 							  sizeof(env->used_btfs[0]),
18976 							  GFP_KERNEL);
18977 		if (!env->prog->aux->used_btfs) {
18978 			ret = -ENOMEM;
18979 			goto err_release_maps;
18980 		}
18981 
18982 		memcpy(env->prog->aux->used_btfs, env->used_btfs,
18983 		       sizeof(env->used_btfs[0]) * env->used_btf_cnt);
18984 		env->prog->aux->used_btf_cnt = env->used_btf_cnt;
18985 	}
18986 	if (env->used_map_cnt || env->used_btf_cnt) {
18987 		/* program is valid. Convert pseudo bpf_ld_imm64 into generic
18988 		 * bpf_ld_imm64 instructions
18989 		 */
18990 		convert_pseudo_ld_imm64(env);
18991 	}
18992 
18993 	adjust_btf_func(env);
18994 
18995 err_release_maps:
18996 	if (!env->prog->aux->used_maps)
18997 		/* if we didn't copy map pointers into bpf_prog_info, release
18998 		 * them now. Otherwise free_used_maps() will release them.
18999 		 */
19000 		release_maps(env);
19001 	if (!env->prog->aux->used_btfs)
19002 		release_btfs(env);
19003 
19004 	/* extension progs temporarily inherit the attach_type of their targets
19005 	   for verification purposes, so set it back to zero before returning
19006 	 */
19007 	if (env->prog->type == BPF_PROG_TYPE_EXT)
19008 		env->prog->expected_attach_type = 0;
19009 
19010 	*prog = env->prog;
19011 err_unlock:
19012 	if (!is_priv)
19013 		mutex_unlock(&bpf_verifier_lock);
19014 	vfree(env->insn_aux_data);
19015 err_free_env:
19016 	kfree(env);
19017 	return ret;
19018 }
19019