xref: /openbmc/linux/include/linux/bpf_verifier.h (revision c6fbb759)
1 /* SPDX-License-Identifier: GPL-2.0-only */
2 /* Copyright (c) 2011-2014 PLUMgrid, http://plumgrid.com
3  */
4 #ifndef _LINUX_BPF_VERIFIER_H
5 #define _LINUX_BPF_VERIFIER_H 1
6 
7 #include <linux/bpf.h> /* for enum bpf_reg_type */
8 #include <linux/btf.h> /* for struct btf and btf_id() */
9 #include <linux/filter.h> /* for MAX_BPF_STACK */
10 #include <linux/tnum.h>
11 
12 /* Maximum variable offset umax_value permitted when resolving memory accesses.
13  * In practice this is far bigger than any realistic pointer offset; this limit
14  * ensures that umax_value + (int)off + (int)size cannot overflow a u64.
15  */
16 #define BPF_MAX_VAR_OFF	(1 << 29)
17 /* Maximum variable size permitted for ARG_CONST_SIZE[_OR_ZERO].  This ensures
18  * that converting umax_value to int cannot overflow.
19  */
20 #define BPF_MAX_VAR_SIZ	(1 << 29)
21 /* size of type_str_buf in bpf_verifier. */
22 #define TYPE_STR_BUF_LEN 64
23 
24 /* Liveness marks, used for registers and spilled-regs (in stack slots).
25  * Read marks propagate upwards until they find a write mark; they record that
26  * "one of this state's descendants read this reg" (and therefore the reg is
27  * relevant for states_equal() checks).
28  * Write marks collect downwards and do not propagate; they record that "the
29  * straight-line code that reached this state (from its parent) wrote this reg"
30  * (and therefore that reads propagated from this state or its descendants
31  * should not propagate to its parent).
32  * A state with a write mark can receive read marks; it just won't propagate
33  * them to its parent, since the write mark is a property, not of the state,
34  * but of the link between it and its parent.  See mark_reg_read() and
35  * mark_stack_slot_read() in kernel/bpf/verifier.c.
36  */
37 enum bpf_reg_liveness {
38 	REG_LIVE_NONE = 0, /* reg hasn't been read or written this branch */
39 	REG_LIVE_READ32 = 0x1, /* reg was read, so we're sensitive to initial value */
40 	REG_LIVE_READ64 = 0x2, /* likewise, but full 64-bit content matters */
41 	REG_LIVE_READ = REG_LIVE_READ32 | REG_LIVE_READ64,
42 	REG_LIVE_WRITTEN = 0x4, /* reg was written first, screening off later reads */
43 	REG_LIVE_DONE = 0x8, /* liveness won't be updating this register anymore */
44 };
45 
46 struct bpf_reg_state {
47 	/* Ordering of fields matters.  See states_equal() */
48 	enum bpf_reg_type type;
49 	/* Fixed part of pointer offset, pointer types only */
50 	s32 off;
51 	union {
52 		/* valid when type == PTR_TO_PACKET */
53 		int range;
54 
55 		/* valid when type == CONST_PTR_TO_MAP | PTR_TO_MAP_VALUE |
56 		 *   PTR_TO_MAP_VALUE_OR_NULL
57 		 */
58 		struct {
59 			struct bpf_map *map_ptr;
60 			/* To distinguish map lookups from outer map
61 			 * the map_uid is non-zero for registers
62 			 * pointing to inner maps.
63 			 */
64 			u32 map_uid;
65 		};
66 
67 		/* for PTR_TO_BTF_ID */
68 		struct {
69 			struct btf *btf;
70 			u32 btf_id;
71 		};
72 
73 		u32 mem_size; /* for PTR_TO_MEM | PTR_TO_MEM_OR_NULL */
74 
75 		/* For dynptr stack slots */
76 		struct {
77 			enum bpf_dynptr_type type;
78 			/* A dynptr is 16 bytes so it takes up 2 stack slots.
79 			 * We need to track which slot is the first slot
80 			 * to protect against cases where the user may try to
81 			 * pass in an address starting at the second slot of the
82 			 * dynptr.
83 			 */
84 			bool first_slot;
85 		} dynptr;
86 
87 		/* Max size from any of the above. */
88 		struct {
89 			unsigned long raw1;
90 			unsigned long raw2;
91 		} raw;
92 
93 		u32 subprogno; /* for PTR_TO_FUNC */
94 	};
95 	/* For PTR_TO_PACKET, used to find other pointers with the same variable
96 	 * offset, so they can share range knowledge.
97 	 * For PTR_TO_MAP_VALUE_OR_NULL this is used to share which map value we
98 	 * came from, when one is tested for != NULL.
99 	 * For PTR_TO_MEM_OR_NULL this is used to identify memory allocation
100 	 * for the purpose of tracking that it's freed.
101 	 * For PTR_TO_SOCKET this is used to share which pointers retain the
102 	 * same reference to the socket, to determine proper reference freeing.
103 	 * For stack slots that are dynptrs, this is used to track references to
104 	 * the dynptr to determine proper reference freeing.
105 	 */
106 	u32 id;
107 	/* PTR_TO_SOCKET and PTR_TO_TCP_SOCK could be a ptr returned
108 	 * from a pointer-cast helper, bpf_sk_fullsock() and
109 	 * bpf_tcp_sock().
110 	 *
111 	 * Consider the following where "sk" is a reference counted
112 	 * pointer returned from "sk = bpf_sk_lookup_tcp();":
113 	 *
114 	 * 1: sk = bpf_sk_lookup_tcp();
115 	 * 2: if (!sk) { return 0; }
116 	 * 3: fullsock = bpf_sk_fullsock(sk);
117 	 * 4: if (!fullsock) { bpf_sk_release(sk); return 0; }
118 	 * 5: tp = bpf_tcp_sock(fullsock);
119 	 * 6: if (!tp) { bpf_sk_release(sk); return 0; }
120 	 * 7: bpf_sk_release(sk);
121 	 * 8: snd_cwnd = tp->snd_cwnd;  // verifier will complain
122 	 *
123 	 * After bpf_sk_release(sk) at line 7, both "fullsock" ptr and
124 	 * "tp" ptr should be invalidated also.  In order to do that,
125 	 * the reg holding "fullsock" and "sk" need to remember
126 	 * the original refcounted ptr id (i.e. sk_reg->id) in ref_obj_id
127 	 * such that the verifier can reset all regs which have
128 	 * ref_obj_id matching the sk_reg->id.
129 	 *
130 	 * sk_reg->ref_obj_id is set to sk_reg->id at line 1.
131 	 * sk_reg->id will stay as NULL-marking purpose only.
132 	 * After NULL-marking is done, sk_reg->id can be reset to 0.
133 	 *
134 	 * After "fullsock = bpf_sk_fullsock(sk);" at line 3,
135 	 * fullsock_reg->ref_obj_id is set to sk_reg->ref_obj_id.
136 	 *
137 	 * After "tp = bpf_tcp_sock(fullsock);" at line 5,
138 	 * tp_reg->ref_obj_id is set to fullsock_reg->ref_obj_id
139 	 * which is the same as sk_reg->ref_obj_id.
140 	 *
141 	 * From the verifier perspective, if sk, fullsock and tp
142 	 * are not NULL, they are the same ptr with different
143 	 * reg->type.  In particular, bpf_sk_release(tp) is also
144 	 * allowed and has the same effect as bpf_sk_release(sk).
145 	 */
146 	u32 ref_obj_id;
147 	/* For scalar types (SCALAR_VALUE), this represents our knowledge of
148 	 * the actual value.
149 	 * For pointer types, this represents the variable part of the offset
150 	 * from the pointed-to object, and is shared with all bpf_reg_states
151 	 * with the same id as us.
152 	 */
153 	struct tnum var_off;
154 	/* Used to determine if any memory access using this register will
155 	 * result in a bad access.
156 	 * These refer to the same value as var_off, not necessarily the actual
157 	 * contents of the register.
158 	 */
159 	s64 smin_value; /* minimum possible (s64)value */
160 	s64 smax_value; /* maximum possible (s64)value */
161 	u64 umin_value; /* minimum possible (u64)value */
162 	u64 umax_value; /* maximum possible (u64)value */
163 	s32 s32_min_value; /* minimum possible (s32)value */
164 	s32 s32_max_value; /* maximum possible (s32)value */
165 	u32 u32_min_value; /* minimum possible (u32)value */
166 	u32 u32_max_value; /* maximum possible (u32)value */
167 	/* parentage chain for liveness checking */
168 	struct bpf_reg_state *parent;
169 	/* Inside the callee two registers can be both PTR_TO_STACK like
170 	 * R1=fp-8 and R2=fp-8, but one of them points to this function stack
171 	 * while another to the caller's stack. To differentiate them 'frameno'
172 	 * is used which is an index in bpf_verifier_state->frame[] array
173 	 * pointing to bpf_func_state.
174 	 */
175 	u32 frameno;
176 	/* Tracks subreg definition. The stored value is the insn_idx of the
177 	 * writing insn. This is safe because subreg_def is used before any insn
178 	 * patching which only happens after main verification finished.
179 	 */
180 	s32 subreg_def;
181 	enum bpf_reg_liveness live;
182 	/* if (!precise && SCALAR_VALUE) min/max/tnum don't affect safety */
183 	bool precise;
184 };
185 
186 enum bpf_stack_slot_type {
187 	STACK_INVALID,    /* nothing was stored in this stack slot */
188 	STACK_SPILL,      /* register spilled into stack */
189 	STACK_MISC,	  /* BPF program wrote some data into this slot */
190 	STACK_ZERO,	  /* BPF program wrote constant zero */
191 	/* A dynptr is stored in this stack slot. The type of dynptr
192 	 * is stored in bpf_stack_state->spilled_ptr.dynptr.type
193 	 */
194 	STACK_DYNPTR,
195 };
196 
197 #define BPF_REG_SIZE 8	/* size of eBPF register in bytes */
198 #define BPF_DYNPTR_SIZE		sizeof(struct bpf_dynptr_kern)
199 #define BPF_DYNPTR_NR_SLOTS		(BPF_DYNPTR_SIZE / BPF_REG_SIZE)
200 
201 struct bpf_stack_state {
202 	struct bpf_reg_state spilled_ptr;
203 	u8 slot_type[BPF_REG_SIZE];
204 };
205 
206 struct bpf_reference_state {
207 	/* Track each reference created with a unique id, even if the same
208 	 * instruction creates the reference multiple times (eg, via CALL).
209 	 */
210 	int id;
211 	/* Instruction where the allocation of this reference occurred. This
212 	 * is used purely to inform the user of a reference leak.
213 	 */
214 	int insn_idx;
215 	/* There can be a case like:
216 	 * main (frame 0)
217 	 *  cb (frame 1)
218 	 *   func (frame 3)
219 	 *    cb (frame 4)
220 	 * Hence for frame 4, if callback_ref just stored boolean, it would be
221 	 * impossible to distinguish nested callback refs. Hence store the
222 	 * frameno and compare that to callback_ref in check_reference_leak when
223 	 * exiting a callback function.
224 	 */
225 	int callback_ref;
226 };
227 
228 /* state of the program:
229  * type of all registers and stack info
230  */
231 struct bpf_func_state {
232 	struct bpf_reg_state regs[MAX_BPF_REG];
233 	/* index of call instruction that called into this func */
234 	int callsite;
235 	/* stack frame number of this function state from pov of
236 	 * enclosing bpf_verifier_state.
237 	 * 0 = main function, 1 = first callee.
238 	 */
239 	u32 frameno;
240 	/* subprog number == index within subprog_info
241 	 * zero == main subprog
242 	 */
243 	u32 subprogno;
244 	/* Every bpf_timer_start will increment async_entry_cnt.
245 	 * It's used to distinguish:
246 	 * void foo(void) { for(;;); }
247 	 * void foo(void) { bpf_timer_set_callback(,foo); }
248 	 */
249 	u32 async_entry_cnt;
250 	bool in_callback_fn;
251 	struct tnum callback_ret_range;
252 	bool in_async_callback_fn;
253 
254 	/* The following fields should be last. See copy_func_state() */
255 	int acquired_refs;
256 	struct bpf_reference_state *refs;
257 	int allocated_stack;
258 	struct bpf_stack_state *stack;
259 };
260 
261 struct bpf_idx_pair {
262 	u32 prev_idx;
263 	u32 idx;
264 };
265 
266 struct bpf_id_pair {
267 	u32 old;
268 	u32 cur;
269 };
270 
271 /* Maximum number of register states that can exist at once */
272 #define BPF_ID_MAP_SIZE (MAX_BPF_REG + MAX_BPF_STACK / BPF_REG_SIZE)
273 #define MAX_CALL_FRAMES 8
274 struct bpf_verifier_state {
275 	/* call stack tracking */
276 	struct bpf_func_state *frame[MAX_CALL_FRAMES];
277 	struct bpf_verifier_state *parent;
278 	/*
279 	 * 'branches' field is the number of branches left to explore:
280 	 * 0 - all possible paths from this state reached bpf_exit or
281 	 * were safely pruned
282 	 * 1 - at least one path is being explored.
283 	 * This state hasn't reached bpf_exit
284 	 * 2 - at least two paths are being explored.
285 	 * This state is an immediate parent of two children.
286 	 * One is fallthrough branch with branches==1 and another
287 	 * state is pushed into stack (to be explored later) also with
288 	 * branches==1. The parent of this state has branches==1.
289 	 * The verifier state tree connected via 'parent' pointer looks like:
290 	 * 1
291 	 * 1
292 	 * 2 -> 1 (first 'if' pushed into stack)
293 	 * 1
294 	 * 2 -> 1 (second 'if' pushed into stack)
295 	 * 1
296 	 * 1
297 	 * 1 bpf_exit.
298 	 *
299 	 * Once do_check() reaches bpf_exit, it calls update_branch_counts()
300 	 * and the verifier state tree will look:
301 	 * 1
302 	 * 1
303 	 * 2 -> 1 (first 'if' pushed into stack)
304 	 * 1
305 	 * 1 -> 1 (second 'if' pushed into stack)
306 	 * 0
307 	 * 0
308 	 * 0 bpf_exit.
309 	 * After pop_stack() the do_check() will resume at second 'if'.
310 	 *
311 	 * If is_state_visited() sees a state with branches > 0 it means
312 	 * there is a loop. If such state is exactly equal to the current state
313 	 * it's an infinite loop. Note states_equal() checks for states
314 	 * equivalency, so two states being 'states_equal' does not mean
315 	 * infinite loop. The exact comparison is provided by
316 	 * states_maybe_looping() function. It's a stronger pre-check and
317 	 * much faster than states_equal().
318 	 *
319 	 * This algorithm may not find all possible infinite loops or
320 	 * loop iteration count may be too high.
321 	 * In such cases BPF_COMPLEXITY_LIMIT_INSNS limit kicks in.
322 	 */
323 	u32 branches;
324 	u32 insn_idx;
325 	u32 curframe;
326 	u32 active_spin_lock;
327 	bool speculative;
328 
329 	/* first and last insn idx of this verifier state */
330 	u32 first_insn_idx;
331 	u32 last_insn_idx;
332 	/* jmp history recorded from first to last.
333 	 * backtracking is using it to go from last to first.
334 	 * For most states jmp_history_cnt is [0-3].
335 	 * For loops can go up to ~40.
336 	 */
337 	struct bpf_idx_pair *jmp_history;
338 	u32 jmp_history_cnt;
339 };
340 
341 #define bpf_get_spilled_reg(slot, frame)				\
342 	(((slot < frame->allocated_stack / BPF_REG_SIZE) &&		\
343 	  (frame->stack[slot].slot_type[0] == STACK_SPILL))		\
344 	 ? &frame->stack[slot].spilled_ptr : NULL)
345 
346 /* Iterate over 'frame', setting 'reg' to either NULL or a spilled register. */
347 #define bpf_for_each_spilled_reg(iter, frame, reg)			\
348 	for (iter = 0, reg = bpf_get_spilled_reg(iter, frame);		\
349 	     iter < frame->allocated_stack / BPF_REG_SIZE;		\
350 	     iter++, reg = bpf_get_spilled_reg(iter, frame))
351 
352 /* Invoke __expr over regsiters in __vst, setting __state and __reg */
353 #define bpf_for_each_reg_in_vstate(__vst, __state, __reg, __expr)   \
354 	({                                                               \
355 		struct bpf_verifier_state *___vstate = __vst;            \
356 		int ___i, ___j;                                          \
357 		for (___i = 0; ___i <= ___vstate->curframe; ___i++) {    \
358 			struct bpf_reg_state *___regs;                   \
359 			__state = ___vstate->frame[___i];                \
360 			___regs = __state->regs;                         \
361 			for (___j = 0; ___j < MAX_BPF_REG; ___j++) {     \
362 				__reg = &___regs[___j];                  \
363 				(void)(__expr);                          \
364 			}                                                \
365 			bpf_for_each_spilled_reg(___j, __state, __reg) { \
366 				if (!__reg)                              \
367 					continue;                        \
368 				(void)(__expr);                          \
369 			}                                                \
370 		}                                                        \
371 	})
372 
373 /* linked list of verifier states used to prune search */
374 struct bpf_verifier_state_list {
375 	struct bpf_verifier_state state;
376 	struct bpf_verifier_state_list *next;
377 	int miss_cnt, hit_cnt;
378 };
379 
380 struct bpf_loop_inline_state {
381 	unsigned int initialized:1; /* set to true upon first entry */
382 	unsigned int fit_for_inline:1; /* true if callback function is the same
383 					* at each call and flags are always zero
384 					*/
385 	u32 callback_subprogno; /* valid when fit_for_inline is true */
386 };
387 
388 /* Possible states for alu_state member. */
389 #define BPF_ALU_SANITIZE_SRC		(1U << 0)
390 #define BPF_ALU_SANITIZE_DST		(1U << 1)
391 #define BPF_ALU_NEG_VALUE		(1U << 2)
392 #define BPF_ALU_NON_POINTER		(1U << 3)
393 #define BPF_ALU_IMMEDIATE		(1U << 4)
394 #define BPF_ALU_SANITIZE		(BPF_ALU_SANITIZE_SRC | \
395 					 BPF_ALU_SANITIZE_DST)
396 
397 struct bpf_insn_aux_data {
398 	union {
399 		enum bpf_reg_type ptr_type;	/* pointer type for load/store insns */
400 		unsigned long map_ptr_state;	/* pointer/poison value for maps */
401 		s32 call_imm;			/* saved imm field of call insn */
402 		u32 alu_limit;			/* limit for add/sub register with pointer */
403 		struct {
404 			u32 map_index;		/* index into used_maps[] */
405 			u32 map_off;		/* offset from value base address */
406 		};
407 		struct {
408 			enum bpf_reg_type reg_type;	/* type of pseudo_btf_id */
409 			union {
410 				struct {
411 					struct btf *btf;
412 					u32 btf_id;	/* btf_id for struct typed var */
413 				};
414 				u32 mem_size;	/* mem_size for non-struct typed var */
415 			};
416 		} btf_var;
417 		/* if instruction is a call to bpf_loop this field tracks
418 		 * the state of the relevant registers to make decision about inlining
419 		 */
420 		struct bpf_loop_inline_state loop_inline_state;
421 	};
422 	u64 map_key_state; /* constant (32 bit) key tracking for maps */
423 	int ctx_field_size; /* the ctx field size for load insn, maybe 0 */
424 	u32 seen; /* this insn was processed by the verifier at env->pass_cnt */
425 	bool sanitize_stack_spill; /* subject to Spectre v4 sanitation */
426 	bool zext_dst; /* this insn zero extends dst reg */
427 	u8 alu_state; /* used in combination with alu_limit */
428 
429 	/* below fields are initialized once */
430 	unsigned int orig_idx; /* original instruction index */
431 	bool prune_point;
432 };
433 
434 #define MAX_USED_MAPS 64 /* max number of maps accessed by one eBPF program */
435 #define MAX_USED_BTFS 64 /* max number of BTFs accessed by one BPF program */
436 
437 #define BPF_VERIFIER_TMP_LOG_SIZE	1024
438 
439 struct bpf_verifier_log {
440 	u32 level;
441 	char kbuf[BPF_VERIFIER_TMP_LOG_SIZE];
442 	char __user *ubuf;
443 	u32 len_used;
444 	u32 len_total;
445 };
446 
447 static inline bool bpf_verifier_log_full(const struct bpf_verifier_log *log)
448 {
449 	return log->len_used >= log->len_total - 1;
450 }
451 
452 #define BPF_LOG_LEVEL1	1
453 #define BPF_LOG_LEVEL2	2
454 #define BPF_LOG_STATS	4
455 #define BPF_LOG_LEVEL	(BPF_LOG_LEVEL1 | BPF_LOG_LEVEL2)
456 #define BPF_LOG_MASK	(BPF_LOG_LEVEL | BPF_LOG_STATS)
457 #define BPF_LOG_KERNEL	(BPF_LOG_MASK + 1) /* kernel internal flag */
458 #define BPF_LOG_MIN_ALIGNMENT 8U
459 #define BPF_LOG_ALIGNMENT 40U
460 
461 static inline bool bpf_verifier_log_needed(const struct bpf_verifier_log *log)
462 {
463 	return log &&
464 		((log->level && log->ubuf && !bpf_verifier_log_full(log)) ||
465 		 log->level == BPF_LOG_KERNEL);
466 }
467 
468 static inline bool
469 bpf_verifier_log_attr_valid(const struct bpf_verifier_log *log)
470 {
471 	return log->len_total >= 128 && log->len_total <= UINT_MAX >> 2 &&
472 	       log->level && log->ubuf && !(log->level & ~BPF_LOG_MASK);
473 }
474 
475 #define BPF_MAX_SUBPROGS 256
476 
477 struct bpf_subprog_info {
478 	/* 'start' has to be the first field otherwise find_subprog() won't work */
479 	u32 start; /* insn idx of function entry point */
480 	u32 linfo_idx; /* The idx to the main_prog->aux->linfo */
481 	u16 stack_depth; /* max. stack depth used by this function */
482 	bool has_tail_call;
483 	bool tail_call_reachable;
484 	bool has_ld_abs;
485 	bool is_async_cb;
486 };
487 
488 /* single container for all structs
489  * one verifier_env per bpf_check() call
490  */
491 struct bpf_verifier_env {
492 	u32 insn_idx;
493 	u32 prev_insn_idx;
494 	struct bpf_prog *prog;		/* eBPF program being verified */
495 	const struct bpf_verifier_ops *ops;
496 	struct bpf_verifier_stack_elem *head; /* stack of verifier states to be processed */
497 	int stack_size;			/* number of states to be processed */
498 	bool strict_alignment;		/* perform strict pointer alignment checks */
499 	bool test_state_freq;		/* test verifier with different pruning frequency */
500 	struct bpf_verifier_state *cur_state; /* current verifier state */
501 	struct bpf_verifier_state_list **explored_states; /* search pruning optimization */
502 	struct bpf_verifier_state_list *free_list;
503 	struct bpf_map *used_maps[MAX_USED_MAPS]; /* array of map's used by eBPF program */
504 	struct btf_mod_pair used_btfs[MAX_USED_BTFS]; /* array of BTF's used by BPF program */
505 	u32 used_map_cnt;		/* number of used maps */
506 	u32 used_btf_cnt;		/* number of used BTF objects */
507 	u32 id_gen;			/* used to generate unique reg IDs */
508 	bool explore_alu_limits;
509 	bool allow_ptr_leaks;
510 	bool allow_uninit_stack;
511 	bool allow_ptr_to_map_access;
512 	bool bpf_capable;
513 	bool bypass_spec_v1;
514 	bool bypass_spec_v4;
515 	bool seen_direct_write;
516 	struct bpf_insn_aux_data *insn_aux_data; /* array of per-insn state */
517 	const struct bpf_line_info *prev_linfo;
518 	struct bpf_verifier_log log;
519 	struct bpf_subprog_info subprog_info[BPF_MAX_SUBPROGS + 1];
520 	struct bpf_id_pair idmap_scratch[BPF_ID_MAP_SIZE];
521 	struct {
522 		int *insn_state;
523 		int *insn_stack;
524 		int cur_stack;
525 	} cfg;
526 	u32 pass_cnt; /* number of times do_check() was called */
527 	u32 subprog_cnt;
528 	/* number of instructions analyzed by the verifier */
529 	u32 prev_insn_processed, insn_processed;
530 	/* number of jmps, calls, exits analyzed so far */
531 	u32 prev_jmps_processed, jmps_processed;
532 	/* total verification time */
533 	u64 verification_time;
534 	/* maximum number of verifier states kept in 'branching' instructions */
535 	u32 max_states_per_insn;
536 	/* total number of allocated verifier states */
537 	u32 total_states;
538 	/* some states are freed during program analysis.
539 	 * this is peak number of states. this number dominates kernel
540 	 * memory consumption during verification
541 	 */
542 	u32 peak_states;
543 	/* longest register parentage chain walked for liveness marking */
544 	u32 longest_mark_read_walk;
545 	bpfptr_t fd_array;
546 
547 	/* bit mask to keep track of whether a register has been accessed
548 	 * since the last time the function state was printed
549 	 */
550 	u32 scratched_regs;
551 	/* Same as scratched_regs but for stack slots */
552 	u64 scratched_stack_slots;
553 	u32 prev_log_len, prev_insn_print_len;
554 	/* buffer used in reg_type_str() to generate reg_type string */
555 	char type_str_buf[TYPE_STR_BUF_LEN];
556 };
557 
558 __printf(2, 0) void bpf_verifier_vlog(struct bpf_verifier_log *log,
559 				      const char *fmt, va_list args);
560 __printf(2, 3) void bpf_verifier_log_write(struct bpf_verifier_env *env,
561 					   const char *fmt, ...);
562 __printf(2, 3) void bpf_log(struct bpf_verifier_log *log,
563 			    const char *fmt, ...);
564 
565 static inline struct bpf_func_state *cur_func(struct bpf_verifier_env *env)
566 {
567 	struct bpf_verifier_state *cur = env->cur_state;
568 
569 	return cur->frame[cur->curframe];
570 }
571 
572 static inline struct bpf_reg_state *cur_regs(struct bpf_verifier_env *env)
573 {
574 	return cur_func(env)->regs;
575 }
576 
577 int bpf_prog_offload_verifier_prep(struct bpf_prog *prog);
578 int bpf_prog_offload_verify_insn(struct bpf_verifier_env *env,
579 				 int insn_idx, int prev_insn_idx);
580 int bpf_prog_offload_finalize(struct bpf_verifier_env *env);
581 void
582 bpf_prog_offload_replace_insn(struct bpf_verifier_env *env, u32 off,
583 			      struct bpf_insn *insn);
584 void
585 bpf_prog_offload_remove_insns(struct bpf_verifier_env *env, u32 off, u32 cnt);
586 
587 int check_ptr_off_reg(struct bpf_verifier_env *env,
588 		      const struct bpf_reg_state *reg, int regno);
589 int check_func_arg_reg_off(struct bpf_verifier_env *env,
590 			   const struct bpf_reg_state *reg, int regno,
591 			   enum bpf_arg_type arg_type);
592 int check_kfunc_mem_size_reg(struct bpf_verifier_env *env, struct bpf_reg_state *reg,
593 			     u32 regno);
594 int check_mem_reg(struct bpf_verifier_env *env, struct bpf_reg_state *reg,
595 		   u32 regno, u32 mem_size);
596 bool is_dynptr_reg_valid_init(struct bpf_verifier_env *env,
597 			      struct bpf_reg_state *reg);
598 bool is_dynptr_type_expected(struct bpf_verifier_env *env,
599 			     struct bpf_reg_state *reg,
600 			     enum bpf_arg_type arg_type);
601 
602 /* this lives here instead of in bpf.h because it needs to dereference tgt_prog */
603 static inline u64 bpf_trampoline_compute_key(const struct bpf_prog *tgt_prog,
604 					     struct btf *btf, u32 btf_id)
605 {
606 	if (tgt_prog)
607 		return ((u64)tgt_prog->aux->id << 32) | btf_id;
608 	else
609 		return ((u64)btf_obj_id(btf) << 32) | 0x80000000 | btf_id;
610 }
611 
612 /* unpack the IDs from the key as constructed above */
613 static inline void bpf_trampoline_unpack_key(u64 key, u32 *obj_id, u32 *btf_id)
614 {
615 	if (obj_id)
616 		*obj_id = key >> 32;
617 	if (btf_id)
618 		*btf_id = key & 0x7FFFFFFF;
619 }
620 
621 int bpf_check_attach_target(struct bpf_verifier_log *log,
622 			    const struct bpf_prog *prog,
623 			    const struct bpf_prog *tgt_prog,
624 			    u32 btf_id,
625 			    struct bpf_attach_target_info *tgt_info);
626 void bpf_free_kfunc_btf_tab(struct bpf_kfunc_btf_tab *tab);
627 
628 int mark_chain_precision(struct bpf_verifier_env *env, int regno);
629 
630 #define BPF_BASE_TYPE_MASK	GENMASK(BPF_BASE_TYPE_BITS - 1, 0)
631 
632 /* extract base type from bpf_{arg, return, reg}_type. */
633 static inline u32 base_type(u32 type)
634 {
635 	return type & BPF_BASE_TYPE_MASK;
636 }
637 
638 /* extract flags from an extended type. See bpf_type_flag in bpf.h. */
639 static inline u32 type_flag(u32 type)
640 {
641 	return type & ~BPF_BASE_TYPE_MASK;
642 }
643 
644 /* only use after check_attach_btf_id() */
645 static inline enum bpf_prog_type resolve_prog_type(struct bpf_prog *prog)
646 {
647 	return prog->type == BPF_PROG_TYPE_EXT ?
648 		prog->aux->dst_prog->type : prog->type;
649 }
650 
651 #endif /* _LINUX_BPF_VERIFIER_H */
652