1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3 * Linux Socket Filter - Kernel level socket filtering
4 *
5 * Based on the design of the Berkeley Packet Filter. The new
6 * internal format has been designed by PLUMgrid:
7 *
8 * Copyright (c) 2011 - 2014 PLUMgrid, http://plumgrid.com
9 *
10 * Authors:
11 *
12 * Jay Schulist <jschlst@samba.org>
13 * Alexei Starovoitov <ast@plumgrid.com>
14 * Daniel Borkmann <dborkman@redhat.com>
15 *
16 * Andi Kleen - Fix a few bad bugs and races.
17 * Kris Katterjohn - Added many additional checks in bpf_check_classic()
18 */
19
20 #include <uapi/linux/btf.h>
21 #include <linux/filter.h>
22 #include <linux/skbuff.h>
23 #include <linux/vmalloc.h>
24 #include <linux/random.h>
25 #include <linux/moduleloader.h>
26 #include <linux/bpf.h>
27 #include <linux/btf.h>
28 #include <linux/objtool.h>
29 #include <linux/rbtree_latch.h>
30 #include <linux/kallsyms.h>
31 #include <linux/rcupdate.h>
32 #include <linux/perf_event.h>
33 #include <linux/extable.h>
34 #include <linux/log2.h>
35 #include <linux/bpf_verifier.h>
36 #include <linux/nodemask.h>
37 #include <linux/nospec.h>
38 #include <linux/bpf_mem_alloc.h>
39 #include <linux/memcontrol.h>
40
41 #include <asm/barrier.h>
42 #include <asm/unaligned.h>
43
44 /* Registers */
45 #define BPF_R0 regs[BPF_REG_0]
46 #define BPF_R1 regs[BPF_REG_1]
47 #define BPF_R2 regs[BPF_REG_2]
48 #define BPF_R3 regs[BPF_REG_3]
49 #define BPF_R4 regs[BPF_REG_4]
50 #define BPF_R5 regs[BPF_REG_5]
51 #define BPF_R6 regs[BPF_REG_6]
52 #define BPF_R7 regs[BPF_REG_7]
53 #define BPF_R8 regs[BPF_REG_8]
54 #define BPF_R9 regs[BPF_REG_9]
55 #define BPF_R10 regs[BPF_REG_10]
56
57 /* Named registers */
58 #define DST regs[insn->dst_reg]
59 #define SRC regs[insn->src_reg]
60 #define FP regs[BPF_REG_FP]
61 #define AX regs[BPF_REG_AX]
62 #define ARG1 regs[BPF_REG_ARG1]
63 #define CTX regs[BPF_REG_CTX]
64 #define OFF insn->off
65 #define IMM insn->imm
66
67 struct bpf_mem_alloc bpf_global_ma;
68 bool bpf_global_ma_set;
69
70 /* No hurry in this branch
71 *
72 * Exported for the bpf jit load helper.
73 */
bpf_internal_load_pointer_neg_helper(const struct sk_buff * skb,int k,unsigned int size)74 void *bpf_internal_load_pointer_neg_helper(const struct sk_buff *skb, int k, unsigned int size)
75 {
76 u8 *ptr = NULL;
77
78 if (k >= SKF_NET_OFF) {
79 ptr = skb_network_header(skb) + k - SKF_NET_OFF;
80 } else if (k >= SKF_LL_OFF) {
81 if (unlikely(!skb_mac_header_was_set(skb)))
82 return NULL;
83 ptr = skb_mac_header(skb) + k - SKF_LL_OFF;
84 }
85 if (ptr >= skb->head && ptr + size <= skb_tail_pointer(skb))
86 return ptr;
87
88 return NULL;
89 }
90
bpf_prog_alloc_no_stats(unsigned int size,gfp_t gfp_extra_flags)91 struct bpf_prog *bpf_prog_alloc_no_stats(unsigned int size, gfp_t gfp_extra_flags)
92 {
93 gfp_t gfp_flags = bpf_memcg_flags(GFP_KERNEL | __GFP_ZERO | gfp_extra_flags);
94 struct bpf_prog_aux *aux;
95 struct bpf_prog *fp;
96
97 size = round_up(size, PAGE_SIZE);
98 fp = __vmalloc(size, gfp_flags);
99 if (fp == NULL)
100 return NULL;
101
102 aux = kzalloc(sizeof(*aux), bpf_memcg_flags(GFP_KERNEL | gfp_extra_flags));
103 if (aux == NULL) {
104 vfree(fp);
105 return NULL;
106 }
107 fp->active = alloc_percpu_gfp(int, bpf_memcg_flags(GFP_KERNEL | gfp_extra_flags));
108 if (!fp->active) {
109 vfree(fp);
110 kfree(aux);
111 return NULL;
112 }
113
114 fp->pages = size / PAGE_SIZE;
115 fp->aux = aux;
116 fp->aux->prog = fp;
117 fp->jit_requested = ebpf_jit_enabled();
118 fp->blinding_requested = bpf_jit_blinding_enabled(fp);
119 #ifdef CONFIG_CGROUP_BPF
120 aux->cgroup_atype = CGROUP_BPF_ATTACH_TYPE_INVALID;
121 #endif
122
123 INIT_LIST_HEAD_RCU(&fp->aux->ksym.lnode);
124 mutex_init(&fp->aux->used_maps_mutex);
125 mutex_init(&fp->aux->dst_mutex);
126
127 return fp;
128 }
129
bpf_prog_alloc(unsigned int size,gfp_t gfp_extra_flags)130 struct bpf_prog *bpf_prog_alloc(unsigned int size, gfp_t gfp_extra_flags)
131 {
132 gfp_t gfp_flags = bpf_memcg_flags(GFP_KERNEL | __GFP_ZERO | gfp_extra_flags);
133 struct bpf_prog *prog;
134 int cpu;
135
136 prog = bpf_prog_alloc_no_stats(size, gfp_extra_flags);
137 if (!prog)
138 return NULL;
139
140 prog->stats = alloc_percpu_gfp(struct bpf_prog_stats, gfp_flags);
141 if (!prog->stats) {
142 free_percpu(prog->active);
143 kfree(prog->aux);
144 vfree(prog);
145 return NULL;
146 }
147
148 for_each_possible_cpu(cpu) {
149 struct bpf_prog_stats *pstats;
150
151 pstats = per_cpu_ptr(prog->stats, cpu);
152 u64_stats_init(&pstats->syncp);
153 }
154 return prog;
155 }
156 EXPORT_SYMBOL_GPL(bpf_prog_alloc);
157
bpf_prog_alloc_jited_linfo(struct bpf_prog * prog)158 int bpf_prog_alloc_jited_linfo(struct bpf_prog *prog)
159 {
160 if (!prog->aux->nr_linfo || !prog->jit_requested)
161 return 0;
162
163 prog->aux->jited_linfo = kvcalloc(prog->aux->nr_linfo,
164 sizeof(*prog->aux->jited_linfo),
165 bpf_memcg_flags(GFP_KERNEL | __GFP_NOWARN));
166 if (!prog->aux->jited_linfo)
167 return -ENOMEM;
168
169 return 0;
170 }
171
bpf_prog_jit_attempt_done(struct bpf_prog * prog)172 void bpf_prog_jit_attempt_done(struct bpf_prog *prog)
173 {
174 if (prog->aux->jited_linfo &&
175 (!prog->jited || !prog->aux->jited_linfo[0])) {
176 kvfree(prog->aux->jited_linfo);
177 prog->aux->jited_linfo = NULL;
178 }
179
180 kfree(prog->aux->kfunc_tab);
181 prog->aux->kfunc_tab = NULL;
182 }
183
184 /* The jit engine is responsible to provide an array
185 * for insn_off to the jited_off mapping (insn_to_jit_off).
186 *
187 * The idx to this array is the insn_off. Hence, the insn_off
188 * here is relative to the prog itself instead of the main prog.
189 * This array has one entry for each xlated bpf insn.
190 *
191 * jited_off is the byte off to the end of the jited insn.
192 *
193 * Hence, with
194 * insn_start:
195 * The first bpf insn off of the prog. The insn off
196 * here is relative to the main prog.
197 * e.g. if prog is a subprog, insn_start > 0
198 * linfo_idx:
199 * The prog's idx to prog->aux->linfo and jited_linfo
200 *
201 * jited_linfo[linfo_idx] = prog->bpf_func
202 *
203 * For i > linfo_idx,
204 *
205 * jited_linfo[i] = prog->bpf_func +
206 * insn_to_jit_off[linfo[i].insn_off - insn_start - 1]
207 */
bpf_prog_fill_jited_linfo(struct bpf_prog * prog,const u32 * insn_to_jit_off)208 void bpf_prog_fill_jited_linfo(struct bpf_prog *prog,
209 const u32 *insn_to_jit_off)
210 {
211 u32 linfo_idx, insn_start, insn_end, nr_linfo, i;
212 const struct bpf_line_info *linfo;
213 void **jited_linfo;
214
215 if (!prog->aux->jited_linfo)
216 /* Userspace did not provide linfo */
217 return;
218
219 linfo_idx = prog->aux->linfo_idx;
220 linfo = &prog->aux->linfo[linfo_idx];
221 insn_start = linfo[0].insn_off;
222 insn_end = insn_start + prog->len;
223
224 jited_linfo = &prog->aux->jited_linfo[linfo_idx];
225 jited_linfo[0] = prog->bpf_func;
226
227 nr_linfo = prog->aux->nr_linfo - linfo_idx;
228
229 for (i = 1; i < nr_linfo && linfo[i].insn_off < insn_end; i++)
230 /* The verifier ensures that linfo[i].insn_off is
231 * strictly increasing
232 */
233 jited_linfo[i] = prog->bpf_func +
234 insn_to_jit_off[linfo[i].insn_off - insn_start - 1];
235 }
236
bpf_prog_realloc(struct bpf_prog * fp_old,unsigned int size,gfp_t gfp_extra_flags)237 struct bpf_prog *bpf_prog_realloc(struct bpf_prog *fp_old, unsigned int size,
238 gfp_t gfp_extra_flags)
239 {
240 gfp_t gfp_flags = bpf_memcg_flags(GFP_KERNEL | __GFP_ZERO | gfp_extra_flags);
241 struct bpf_prog *fp;
242 u32 pages;
243
244 size = round_up(size, PAGE_SIZE);
245 pages = size / PAGE_SIZE;
246 if (pages <= fp_old->pages)
247 return fp_old;
248
249 fp = __vmalloc(size, gfp_flags);
250 if (fp) {
251 memcpy(fp, fp_old, fp_old->pages * PAGE_SIZE);
252 fp->pages = pages;
253 fp->aux->prog = fp;
254
255 /* We keep fp->aux from fp_old around in the new
256 * reallocated structure.
257 */
258 fp_old->aux = NULL;
259 fp_old->stats = NULL;
260 fp_old->active = NULL;
261 __bpf_prog_free(fp_old);
262 }
263
264 return fp;
265 }
266
__bpf_prog_free(struct bpf_prog * fp)267 void __bpf_prog_free(struct bpf_prog *fp)
268 {
269 if (fp->aux) {
270 mutex_destroy(&fp->aux->used_maps_mutex);
271 mutex_destroy(&fp->aux->dst_mutex);
272 kfree(fp->aux->poke_tab);
273 kfree(fp->aux);
274 }
275 free_percpu(fp->stats);
276 free_percpu(fp->active);
277 vfree(fp);
278 }
279
bpf_prog_calc_tag(struct bpf_prog * fp)280 int bpf_prog_calc_tag(struct bpf_prog *fp)
281 {
282 const u32 bits_offset = SHA1_BLOCK_SIZE - sizeof(__be64);
283 u32 raw_size = bpf_prog_tag_scratch_size(fp);
284 u32 digest[SHA1_DIGEST_WORDS];
285 u32 ws[SHA1_WORKSPACE_WORDS];
286 u32 i, bsize, psize, blocks;
287 struct bpf_insn *dst;
288 bool was_ld_map;
289 u8 *raw, *todo;
290 __be32 *result;
291 __be64 *bits;
292
293 raw = vmalloc(raw_size);
294 if (!raw)
295 return -ENOMEM;
296
297 sha1_init(digest);
298 memset(ws, 0, sizeof(ws));
299
300 /* We need to take out the map fd for the digest calculation
301 * since they are unstable from user space side.
302 */
303 dst = (void *)raw;
304 for (i = 0, was_ld_map = false; i < fp->len; i++) {
305 dst[i] = fp->insnsi[i];
306 if (!was_ld_map &&
307 dst[i].code == (BPF_LD | BPF_IMM | BPF_DW) &&
308 (dst[i].src_reg == BPF_PSEUDO_MAP_FD ||
309 dst[i].src_reg == BPF_PSEUDO_MAP_VALUE)) {
310 was_ld_map = true;
311 dst[i].imm = 0;
312 } else if (was_ld_map &&
313 dst[i].code == 0 &&
314 dst[i].dst_reg == 0 &&
315 dst[i].src_reg == 0 &&
316 dst[i].off == 0) {
317 was_ld_map = false;
318 dst[i].imm = 0;
319 } else {
320 was_ld_map = false;
321 }
322 }
323
324 psize = bpf_prog_insn_size(fp);
325 memset(&raw[psize], 0, raw_size - psize);
326 raw[psize++] = 0x80;
327
328 bsize = round_up(psize, SHA1_BLOCK_SIZE);
329 blocks = bsize / SHA1_BLOCK_SIZE;
330 todo = raw;
331 if (bsize - psize >= sizeof(__be64)) {
332 bits = (__be64 *)(todo + bsize - sizeof(__be64));
333 } else {
334 bits = (__be64 *)(todo + bsize + bits_offset);
335 blocks++;
336 }
337 *bits = cpu_to_be64((psize - 1) << 3);
338
339 while (blocks--) {
340 sha1_transform(digest, todo, ws);
341 todo += SHA1_BLOCK_SIZE;
342 }
343
344 result = (__force __be32 *)digest;
345 for (i = 0; i < SHA1_DIGEST_WORDS; i++)
346 result[i] = cpu_to_be32(digest[i]);
347 memcpy(fp->tag, result, sizeof(fp->tag));
348
349 vfree(raw);
350 return 0;
351 }
352
bpf_adj_delta_to_imm(struct bpf_insn * insn,u32 pos,s32 end_old,s32 end_new,s32 curr,const bool probe_pass)353 static int bpf_adj_delta_to_imm(struct bpf_insn *insn, u32 pos, s32 end_old,
354 s32 end_new, s32 curr, const bool probe_pass)
355 {
356 const s64 imm_min = S32_MIN, imm_max = S32_MAX;
357 s32 delta = end_new - end_old;
358 s64 imm = insn->imm;
359
360 if (curr < pos && curr + imm + 1 >= end_old)
361 imm += delta;
362 else if (curr >= end_new && curr + imm + 1 < end_new)
363 imm -= delta;
364 if (imm < imm_min || imm > imm_max)
365 return -ERANGE;
366 if (!probe_pass)
367 insn->imm = imm;
368 return 0;
369 }
370
bpf_adj_delta_to_off(struct bpf_insn * insn,u32 pos,s32 end_old,s32 end_new,s32 curr,const bool probe_pass)371 static int bpf_adj_delta_to_off(struct bpf_insn *insn, u32 pos, s32 end_old,
372 s32 end_new, s32 curr, const bool probe_pass)
373 {
374 s64 off_min, off_max, off;
375 s32 delta = end_new - end_old;
376
377 if (insn->code == (BPF_JMP32 | BPF_JA)) {
378 off = insn->imm;
379 off_min = S32_MIN;
380 off_max = S32_MAX;
381 } else {
382 off = insn->off;
383 off_min = S16_MIN;
384 off_max = S16_MAX;
385 }
386
387 if (curr < pos && curr + off + 1 >= end_old)
388 off += delta;
389 else if (curr >= end_new && curr + off + 1 < end_new)
390 off -= delta;
391 if (off < off_min || off > off_max)
392 return -ERANGE;
393 if (!probe_pass) {
394 if (insn->code == (BPF_JMP32 | BPF_JA))
395 insn->imm = off;
396 else
397 insn->off = off;
398 }
399 return 0;
400 }
401
bpf_adj_branches(struct bpf_prog * prog,u32 pos,s32 end_old,s32 end_new,const bool probe_pass)402 static int bpf_adj_branches(struct bpf_prog *prog, u32 pos, s32 end_old,
403 s32 end_new, const bool probe_pass)
404 {
405 u32 i, insn_cnt = prog->len + (probe_pass ? end_new - end_old : 0);
406 struct bpf_insn *insn = prog->insnsi;
407 int ret = 0;
408
409 for (i = 0; i < insn_cnt; i++, insn++) {
410 u8 code;
411
412 /* In the probing pass we still operate on the original,
413 * unpatched image in order to check overflows before we
414 * do any other adjustments. Therefore skip the patchlet.
415 */
416 if (probe_pass && i == pos) {
417 i = end_new;
418 insn = prog->insnsi + end_old;
419 }
420 if (bpf_pseudo_func(insn)) {
421 ret = bpf_adj_delta_to_imm(insn, pos, end_old,
422 end_new, i, probe_pass);
423 if (ret)
424 return ret;
425 continue;
426 }
427 code = insn->code;
428 if ((BPF_CLASS(code) != BPF_JMP &&
429 BPF_CLASS(code) != BPF_JMP32) ||
430 BPF_OP(code) == BPF_EXIT)
431 continue;
432 /* Adjust offset of jmps if we cross patch boundaries. */
433 if (BPF_OP(code) == BPF_CALL) {
434 if (insn->src_reg != BPF_PSEUDO_CALL)
435 continue;
436 ret = bpf_adj_delta_to_imm(insn, pos, end_old,
437 end_new, i, probe_pass);
438 } else {
439 ret = bpf_adj_delta_to_off(insn, pos, end_old,
440 end_new, i, probe_pass);
441 }
442 if (ret)
443 break;
444 }
445
446 return ret;
447 }
448
bpf_adj_linfo(struct bpf_prog * prog,u32 off,u32 delta)449 static void bpf_adj_linfo(struct bpf_prog *prog, u32 off, u32 delta)
450 {
451 struct bpf_line_info *linfo;
452 u32 i, nr_linfo;
453
454 nr_linfo = prog->aux->nr_linfo;
455 if (!nr_linfo || !delta)
456 return;
457
458 linfo = prog->aux->linfo;
459
460 for (i = 0; i < nr_linfo; i++)
461 if (off < linfo[i].insn_off)
462 break;
463
464 /* Push all off < linfo[i].insn_off by delta */
465 for (; i < nr_linfo; i++)
466 linfo[i].insn_off += delta;
467 }
468
bpf_patch_insn_single(struct bpf_prog * prog,u32 off,const struct bpf_insn * patch,u32 len)469 struct bpf_prog *bpf_patch_insn_single(struct bpf_prog *prog, u32 off,
470 const struct bpf_insn *patch, u32 len)
471 {
472 u32 insn_adj_cnt, insn_rest, insn_delta = len - 1;
473 const u32 cnt_max = S16_MAX;
474 struct bpf_prog *prog_adj;
475 int err;
476
477 /* Since our patchlet doesn't expand the image, we're done. */
478 if (insn_delta == 0) {
479 memcpy(prog->insnsi + off, patch, sizeof(*patch));
480 return prog;
481 }
482
483 insn_adj_cnt = prog->len + insn_delta;
484
485 /* Reject anything that would potentially let the insn->off
486 * target overflow when we have excessive program expansions.
487 * We need to probe here before we do any reallocation where
488 * we afterwards may not fail anymore.
489 */
490 if (insn_adj_cnt > cnt_max &&
491 (err = bpf_adj_branches(prog, off, off + 1, off + len, true)))
492 return ERR_PTR(err);
493
494 /* Several new instructions need to be inserted. Make room
495 * for them. Likely, there's no need for a new allocation as
496 * last page could have large enough tailroom.
497 */
498 prog_adj = bpf_prog_realloc(prog, bpf_prog_size(insn_adj_cnt),
499 GFP_USER);
500 if (!prog_adj)
501 return ERR_PTR(-ENOMEM);
502
503 prog_adj->len = insn_adj_cnt;
504
505 /* Patching happens in 3 steps:
506 *
507 * 1) Move over tail of insnsi from next instruction onwards,
508 * so we can patch the single target insn with one or more
509 * new ones (patching is always from 1 to n insns, n > 0).
510 * 2) Inject new instructions at the target location.
511 * 3) Adjust branch offsets if necessary.
512 */
513 insn_rest = insn_adj_cnt - off - len;
514
515 memmove(prog_adj->insnsi + off + len, prog_adj->insnsi + off + 1,
516 sizeof(*patch) * insn_rest);
517 memcpy(prog_adj->insnsi + off, patch, sizeof(*patch) * len);
518
519 /* We are guaranteed to not fail at this point, otherwise
520 * the ship has sailed to reverse to the original state. An
521 * overflow cannot happen at this point.
522 */
523 BUG_ON(bpf_adj_branches(prog_adj, off, off + 1, off + len, false));
524
525 bpf_adj_linfo(prog_adj, off, insn_delta);
526
527 return prog_adj;
528 }
529
bpf_remove_insns(struct bpf_prog * prog,u32 off,u32 cnt)530 int bpf_remove_insns(struct bpf_prog *prog, u32 off, u32 cnt)
531 {
532 /* Branch offsets can't overflow when program is shrinking, no need
533 * to call bpf_adj_branches(..., true) here
534 */
535 memmove(prog->insnsi + off, prog->insnsi + off + cnt,
536 sizeof(struct bpf_insn) * (prog->len - off - cnt));
537 prog->len -= cnt;
538
539 return WARN_ON_ONCE(bpf_adj_branches(prog, off, off + cnt, off, false));
540 }
541
bpf_prog_kallsyms_del_subprogs(struct bpf_prog * fp)542 static void bpf_prog_kallsyms_del_subprogs(struct bpf_prog *fp)
543 {
544 int i;
545
546 for (i = 0; i < fp->aux->func_cnt; i++)
547 bpf_prog_kallsyms_del(fp->aux->func[i]);
548 }
549
bpf_prog_kallsyms_del_all(struct bpf_prog * fp)550 void bpf_prog_kallsyms_del_all(struct bpf_prog *fp)
551 {
552 bpf_prog_kallsyms_del_subprogs(fp);
553 bpf_prog_kallsyms_del(fp);
554 }
555
556 #ifdef CONFIG_BPF_JIT
557 /* All BPF JIT sysctl knobs here. */
558 int bpf_jit_enable __read_mostly = IS_BUILTIN(CONFIG_BPF_JIT_DEFAULT_ON);
559 int bpf_jit_kallsyms __read_mostly = IS_BUILTIN(CONFIG_BPF_JIT_DEFAULT_ON);
560 int bpf_jit_harden __read_mostly;
561 long bpf_jit_limit __read_mostly;
562 long bpf_jit_limit_max __read_mostly;
563
564 static void
bpf_prog_ksym_set_addr(struct bpf_prog * prog)565 bpf_prog_ksym_set_addr(struct bpf_prog *prog)
566 {
567 WARN_ON_ONCE(!bpf_prog_ebpf_jited(prog));
568
569 prog->aux->ksym.start = (unsigned long) prog->bpf_func;
570 prog->aux->ksym.end = prog->aux->ksym.start + prog->jited_len;
571 }
572
573 static void
bpf_prog_ksym_set_name(struct bpf_prog * prog)574 bpf_prog_ksym_set_name(struct bpf_prog *prog)
575 {
576 char *sym = prog->aux->ksym.name;
577 const char *end = sym + KSYM_NAME_LEN;
578 const struct btf_type *type;
579 const char *func_name;
580
581 BUILD_BUG_ON(sizeof("bpf_prog_") +
582 sizeof(prog->tag) * 2 +
583 /* name has been null terminated.
584 * We should need +1 for the '_' preceding
585 * the name. However, the null character
586 * is double counted between the name and the
587 * sizeof("bpf_prog_") above, so we omit
588 * the +1 here.
589 */
590 sizeof(prog->aux->name) > KSYM_NAME_LEN);
591
592 sym += snprintf(sym, KSYM_NAME_LEN, "bpf_prog_");
593 sym = bin2hex(sym, prog->tag, sizeof(prog->tag));
594
595 /* prog->aux->name will be ignored if full btf name is available */
596 if (prog->aux->func_info_cnt) {
597 type = btf_type_by_id(prog->aux->btf,
598 prog->aux->func_info[prog->aux->func_idx].type_id);
599 func_name = btf_name_by_offset(prog->aux->btf, type->name_off);
600 snprintf(sym, (size_t)(end - sym), "_%s", func_name);
601 return;
602 }
603
604 if (prog->aux->name[0])
605 snprintf(sym, (size_t)(end - sym), "_%s", prog->aux->name);
606 else
607 *sym = 0;
608 }
609
bpf_get_ksym_start(struct latch_tree_node * n)610 static unsigned long bpf_get_ksym_start(struct latch_tree_node *n)
611 {
612 return container_of(n, struct bpf_ksym, tnode)->start;
613 }
614
bpf_tree_less(struct latch_tree_node * a,struct latch_tree_node * b)615 static __always_inline bool bpf_tree_less(struct latch_tree_node *a,
616 struct latch_tree_node *b)
617 {
618 return bpf_get_ksym_start(a) < bpf_get_ksym_start(b);
619 }
620
bpf_tree_comp(void * key,struct latch_tree_node * n)621 static __always_inline int bpf_tree_comp(void *key, struct latch_tree_node *n)
622 {
623 unsigned long val = (unsigned long)key;
624 const struct bpf_ksym *ksym;
625
626 ksym = container_of(n, struct bpf_ksym, tnode);
627
628 if (val < ksym->start)
629 return -1;
630 /* Ensure that we detect return addresses as part of the program, when
631 * the final instruction is a call for a program part of the stack
632 * trace. Therefore, do val > ksym->end instead of val >= ksym->end.
633 */
634 if (val > ksym->end)
635 return 1;
636
637 return 0;
638 }
639
640 static const struct latch_tree_ops bpf_tree_ops = {
641 .less = bpf_tree_less,
642 .comp = bpf_tree_comp,
643 };
644
645 static DEFINE_SPINLOCK(bpf_lock);
646 static LIST_HEAD(bpf_kallsyms);
647 static struct latch_tree_root bpf_tree __cacheline_aligned;
648
bpf_ksym_add(struct bpf_ksym * ksym)649 void bpf_ksym_add(struct bpf_ksym *ksym)
650 {
651 spin_lock_bh(&bpf_lock);
652 WARN_ON_ONCE(!list_empty(&ksym->lnode));
653 list_add_tail_rcu(&ksym->lnode, &bpf_kallsyms);
654 latch_tree_insert(&ksym->tnode, &bpf_tree, &bpf_tree_ops);
655 spin_unlock_bh(&bpf_lock);
656 }
657
__bpf_ksym_del(struct bpf_ksym * ksym)658 static void __bpf_ksym_del(struct bpf_ksym *ksym)
659 {
660 if (list_empty(&ksym->lnode))
661 return;
662
663 latch_tree_erase(&ksym->tnode, &bpf_tree, &bpf_tree_ops);
664 list_del_rcu(&ksym->lnode);
665 }
666
bpf_ksym_del(struct bpf_ksym * ksym)667 void bpf_ksym_del(struct bpf_ksym *ksym)
668 {
669 spin_lock_bh(&bpf_lock);
670 __bpf_ksym_del(ksym);
671 spin_unlock_bh(&bpf_lock);
672 }
673
bpf_prog_kallsyms_candidate(const struct bpf_prog * fp)674 static bool bpf_prog_kallsyms_candidate(const struct bpf_prog *fp)
675 {
676 return fp->jited && !bpf_prog_was_classic(fp);
677 }
678
bpf_prog_kallsyms_add(struct bpf_prog * fp)679 void bpf_prog_kallsyms_add(struct bpf_prog *fp)
680 {
681 if (!bpf_prog_kallsyms_candidate(fp) ||
682 !bpf_capable())
683 return;
684
685 bpf_prog_ksym_set_addr(fp);
686 bpf_prog_ksym_set_name(fp);
687 fp->aux->ksym.prog = true;
688
689 bpf_ksym_add(&fp->aux->ksym);
690 }
691
bpf_prog_kallsyms_del(struct bpf_prog * fp)692 void bpf_prog_kallsyms_del(struct bpf_prog *fp)
693 {
694 if (!bpf_prog_kallsyms_candidate(fp))
695 return;
696
697 bpf_ksym_del(&fp->aux->ksym);
698 }
699
bpf_ksym_find(unsigned long addr)700 static struct bpf_ksym *bpf_ksym_find(unsigned long addr)
701 {
702 struct latch_tree_node *n;
703
704 n = latch_tree_find((void *)addr, &bpf_tree, &bpf_tree_ops);
705 return n ? container_of(n, struct bpf_ksym, tnode) : NULL;
706 }
707
__bpf_address_lookup(unsigned long addr,unsigned long * size,unsigned long * off,char * sym)708 const char *__bpf_address_lookup(unsigned long addr, unsigned long *size,
709 unsigned long *off, char *sym)
710 {
711 struct bpf_ksym *ksym;
712 char *ret = NULL;
713
714 rcu_read_lock();
715 ksym = bpf_ksym_find(addr);
716 if (ksym) {
717 unsigned long symbol_start = ksym->start;
718 unsigned long symbol_end = ksym->end;
719
720 strncpy(sym, ksym->name, KSYM_NAME_LEN);
721
722 ret = sym;
723 if (size)
724 *size = symbol_end - symbol_start;
725 if (off)
726 *off = addr - symbol_start;
727 }
728 rcu_read_unlock();
729
730 return ret;
731 }
732
is_bpf_text_address(unsigned long addr)733 bool is_bpf_text_address(unsigned long addr)
734 {
735 bool ret;
736
737 rcu_read_lock();
738 ret = bpf_ksym_find(addr) != NULL;
739 rcu_read_unlock();
740
741 return ret;
742 }
743
bpf_prog_ksym_find(unsigned long addr)744 static struct bpf_prog *bpf_prog_ksym_find(unsigned long addr)
745 {
746 struct bpf_ksym *ksym = bpf_ksym_find(addr);
747
748 return ksym && ksym->prog ?
749 container_of(ksym, struct bpf_prog_aux, ksym)->prog :
750 NULL;
751 }
752
search_bpf_extables(unsigned long addr)753 const struct exception_table_entry *search_bpf_extables(unsigned long addr)
754 {
755 const struct exception_table_entry *e = NULL;
756 struct bpf_prog *prog;
757
758 rcu_read_lock();
759 prog = bpf_prog_ksym_find(addr);
760 if (!prog)
761 goto out;
762 if (!prog->aux->num_exentries)
763 goto out;
764
765 e = search_extable(prog->aux->extable, prog->aux->num_exentries, addr);
766 out:
767 rcu_read_unlock();
768 return e;
769 }
770
bpf_get_kallsym(unsigned int symnum,unsigned long * value,char * type,char * sym)771 int bpf_get_kallsym(unsigned int symnum, unsigned long *value, char *type,
772 char *sym)
773 {
774 struct bpf_ksym *ksym;
775 unsigned int it = 0;
776 int ret = -ERANGE;
777
778 if (!bpf_jit_kallsyms_enabled())
779 return ret;
780
781 rcu_read_lock();
782 list_for_each_entry_rcu(ksym, &bpf_kallsyms, lnode) {
783 if (it++ != symnum)
784 continue;
785
786 strncpy(sym, ksym->name, KSYM_NAME_LEN);
787
788 *value = ksym->start;
789 *type = BPF_SYM_ELF_TYPE;
790
791 ret = 0;
792 break;
793 }
794 rcu_read_unlock();
795
796 return ret;
797 }
798
bpf_jit_add_poke_descriptor(struct bpf_prog * prog,struct bpf_jit_poke_descriptor * poke)799 int bpf_jit_add_poke_descriptor(struct bpf_prog *prog,
800 struct bpf_jit_poke_descriptor *poke)
801 {
802 struct bpf_jit_poke_descriptor *tab = prog->aux->poke_tab;
803 static const u32 poke_tab_max = 1024;
804 u32 slot = prog->aux->size_poke_tab;
805 u32 size = slot + 1;
806
807 if (size > poke_tab_max)
808 return -ENOSPC;
809 if (poke->tailcall_target || poke->tailcall_target_stable ||
810 poke->tailcall_bypass || poke->adj_off || poke->bypass_addr)
811 return -EINVAL;
812
813 switch (poke->reason) {
814 case BPF_POKE_REASON_TAIL_CALL:
815 if (!poke->tail_call.map)
816 return -EINVAL;
817 break;
818 default:
819 return -EINVAL;
820 }
821
822 tab = krealloc(tab, size * sizeof(*poke), GFP_KERNEL);
823 if (!tab)
824 return -ENOMEM;
825
826 memcpy(&tab[slot], poke, sizeof(*poke));
827 prog->aux->size_poke_tab = size;
828 prog->aux->poke_tab = tab;
829
830 return slot;
831 }
832
833 /*
834 * BPF program pack allocator.
835 *
836 * Most BPF programs are pretty small. Allocating a hole page for each
837 * program is sometime a waste. Many small bpf program also adds pressure
838 * to instruction TLB. To solve this issue, we introduce a BPF program pack
839 * allocator. The prog_pack allocator uses HPAGE_PMD_SIZE page (2MB on x86)
840 * to host BPF programs.
841 */
842 #define BPF_PROG_CHUNK_SHIFT 6
843 #define BPF_PROG_CHUNK_SIZE (1 << BPF_PROG_CHUNK_SHIFT)
844 #define BPF_PROG_CHUNK_MASK (~(BPF_PROG_CHUNK_SIZE - 1))
845
846 struct bpf_prog_pack {
847 struct list_head list;
848 void *ptr;
849 unsigned long bitmap[];
850 };
851
bpf_jit_fill_hole_with_zero(void * area,unsigned int size)852 void bpf_jit_fill_hole_with_zero(void *area, unsigned int size)
853 {
854 memset(area, 0, size);
855 }
856
857 #define BPF_PROG_SIZE_TO_NBITS(size) (round_up(size, BPF_PROG_CHUNK_SIZE) / BPF_PROG_CHUNK_SIZE)
858
859 static DEFINE_MUTEX(pack_mutex);
860 static LIST_HEAD(pack_list);
861
862 /* PMD_SIZE is not available in some special config, e.g. ARCH=arm with
863 * CONFIG_MMU=n. Use PAGE_SIZE in these cases.
864 */
865 #ifdef PMD_SIZE
866 /* PMD_SIZE is really big for some archs. It doesn't make sense to
867 * reserve too much memory in one allocation. Hardcode BPF_PROG_PACK_SIZE to
868 * 2MiB * num_possible_nodes(). On most architectures PMD_SIZE will be
869 * greater than or equal to 2MB.
870 */
871 #define BPF_PROG_PACK_SIZE (SZ_2M * num_possible_nodes())
872 #else
873 #define BPF_PROG_PACK_SIZE PAGE_SIZE
874 #endif
875
876 #define BPF_PROG_CHUNK_COUNT (BPF_PROG_PACK_SIZE / BPF_PROG_CHUNK_SIZE)
877
alloc_new_pack(bpf_jit_fill_hole_t bpf_fill_ill_insns)878 static struct bpf_prog_pack *alloc_new_pack(bpf_jit_fill_hole_t bpf_fill_ill_insns)
879 {
880 struct bpf_prog_pack *pack;
881
882 pack = kzalloc(struct_size(pack, bitmap, BITS_TO_LONGS(BPF_PROG_CHUNK_COUNT)),
883 GFP_KERNEL);
884 if (!pack)
885 return NULL;
886 pack->ptr = bpf_jit_alloc_exec(BPF_PROG_PACK_SIZE);
887 if (!pack->ptr) {
888 kfree(pack);
889 return NULL;
890 }
891 bpf_fill_ill_insns(pack->ptr, BPF_PROG_PACK_SIZE);
892 bitmap_zero(pack->bitmap, BPF_PROG_PACK_SIZE / BPF_PROG_CHUNK_SIZE);
893 list_add_tail(&pack->list, &pack_list);
894
895 set_vm_flush_reset_perms(pack->ptr);
896 set_memory_rox((unsigned long)pack->ptr, BPF_PROG_PACK_SIZE / PAGE_SIZE);
897 return pack;
898 }
899
bpf_prog_pack_alloc(u32 size,bpf_jit_fill_hole_t bpf_fill_ill_insns)900 void *bpf_prog_pack_alloc(u32 size, bpf_jit_fill_hole_t bpf_fill_ill_insns)
901 {
902 unsigned int nbits = BPF_PROG_SIZE_TO_NBITS(size);
903 struct bpf_prog_pack *pack;
904 unsigned long pos;
905 void *ptr = NULL;
906
907 mutex_lock(&pack_mutex);
908 if (size > BPF_PROG_PACK_SIZE) {
909 size = round_up(size, PAGE_SIZE);
910 ptr = bpf_jit_alloc_exec(size);
911 if (ptr) {
912 bpf_fill_ill_insns(ptr, size);
913 set_vm_flush_reset_perms(ptr);
914 set_memory_rox((unsigned long)ptr, size / PAGE_SIZE);
915 }
916 goto out;
917 }
918 list_for_each_entry(pack, &pack_list, list) {
919 pos = bitmap_find_next_zero_area(pack->bitmap, BPF_PROG_CHUNK_COUNT, 0,
920 nbits, 0);
921 if (pos < BPF_PROG_CHUNK_COUNT)
922 goto found_free_area;
923 }
924
925 pack = alloc_new_pack(bpf_fill_ill_insns);
926 if (!pack)
927 goto out;
928
929 pos = 0;
930
931 found_free_area:
932 bitmap_set(pack->bitmap, pos, nbits);
933 ptr = (void *)(pack->ptr) + (pos << BPF_PROG_CHUNK_SHIFT);
934
935 out:
936 mutex_unlock(&pack_mutex);
937 return ptr;
938 }
939
bpf_prog_pack_free(struct bpf_binary_header * hdr)940 void bpf_prog_pack_free(struct bpf_binary_header *hdr)
941 {
942 struct bpf_prog_pack *pack = NULL, *tmp;
943 unsigned int nbits;
944 unsigned long pos;
945
946 mutex_lock(&pack_mutex);
947 if (hdr->size > BPF_PROG_PACK_SIZE) {
948 bpf_jit_free_exec(hdr);
949 goto out;
950 }
951
952 list_for_each_entry(tmp, &pack_list, list) {
953 if ((void *)hdr >= tmp->ptr && (tmp->ptr + BPF_PROG_PACK_SIZE) > (void *)hdr) {
954 pack = tmp;
955 break;
956 }
957 }
958
959 if (WARN_ONCE(!pack, "bpf_prog_pack bug\n"))
960 goto out;
961
962 nbits = BPF_PROG_SIZE_TO_NBITS(hdr->size);
963 pos = ((unsigned long)hdr - (unsigned long)pack->ptr) >> BPF_PROG_CHUNK_SHIFT;
964
965 WARN_ONCE(bpf_arch_text_invalidate(hdr, hdr->size),
966 "bpf_prog_pack bug: missing bpf_arch_text_invalidate?\n");
967
968 bitmap_clear(pack->bitmap, pos, nbits);
969 if (bitmap_find_next_zero_area(pack->bitmap, BPF_PROG_CHUNK_COUNT, 0,
970 BPF_PROG_CHUNK_COUNT, 0) == 0) {
971 list_del(&pack->list);
972 bpf_jit_free_exec(pack->ptr);
973 kfree(pack);
974 }
975 out:
976 mutex_unlock(&pack_mutex);
977 }
978
979 static atomic_long_t bpf_jit_current;
980
981 /* Can be overridden by an arch's JIT compiler if it has a custom,
982 * dedicated BPF backend memory area, or if neither of the two
983 * below apply.
984 */
bpf_jit_alloc_exec_limit(void)985 u64 __weak bpf_jit_alloc_exec_limit(void)
986 {
987 #if defined(MODULES_VADDR)
988 return MODULES_END - MODULES_VADDR;
989 #else
990 return VMALLOC_END - VMALLOC_START;
991 #endif
992 }
993
bpf_jit_charge_init(void)994 static int __init bpf_jit_charge_init(void)
995 {
996 /* Only used as heuristic here to derive limit. */
997 bpf_jit_limit_max = bpf_jit_alloc_exec_limit();
998 bpf_jit_limit = min_t(u64, round_up(bpf_jit_limit_max >> 1,
999 PAGE_SIZE), LONG_MAX);
1000 return 0;
1001 }
1002 pure_initcall(bpf_jit_charge_init);
1003
bpf_jit_charge_modmem(u32 size)1004 int bpf_jit_charge_modmem(u32 size)
1005 {
1006 if (atomic_long_add_return(size, &bpf_jit_current) > READ_ONCE(bpf_jit_limit)) {
1007 if (!bpf_capable()) {
1008 atomic_long_sub(size, &bpf_jit_current);
1009 return -EPERM;
1010 }
1011 }
1012
1013 return 0;
1014 }
1015
bpf_jit_uncharge_modmem(u32 size)1016 void bpf_jit_uncharge_modmem(u32 size)
1017 {
1018 atomic_long_sub(size, &bpf_jit_current);
1019 }
1020
bpf_jit_alloc_exec(unsigned long size)1021 void *__weak bpf_jit_alloc_exec(unsigned long size)
1022 {
1023 return module_alloc(size);
1024 }
1025
bpf_jit_free_exec(void * addr)1026 void __weak bpf_jit_free_exec(void *addr)
1027 {
1028 module_memfree(addr);
1029 }
1030
1031 struct bpf_binary_header *
bpf_jit_binary_alloc(unsigned int proglen,u8 ** image_ptr,unsigned int alignment,bpf_jit_fill_hole_t bpf_fill_ill_insns)1032 bpf_jit_binary_alloc(unsigned int proglen, u8 **image_ptr,
1033 unsigned int alignment,
1034 bpf_jit_fill_hole_t bpf_fill_ill_insns)
1035 {
1036 struct bpf_binary_header *hdr;
1037 u32 size, hole, start;
1038
1039 WARN_ON_ONCE(!is_power_of_2(alignment) ||
1040 alignment > BPF_IMAGE_ALIGNMENT);
1041
1042 /* Most of BPF filters are really small, but if some of them
1043 * fill a page, allow at least 128 extra bytes to insert a
1044 * random section of illegal instructions.
1045 */
1046 size = round_up(proglen + sizeof(*hdr) + 128, PAGE_SIZE);
1047
1048 if (bpf_jit_charge_modmem(size))
1049 return NULL;
1050 hdr = bpf_jit_alloc_exec(size);
1051 if (!hdr) {
1052 bpf_jit_uncharge_modmem(size);
1053 return NULL;
1054 }
1055
1056 /* Fill space with illegal/arch-dep instructions. */
1057 bpf_fill_ill_insns(hdr, size);
1058
1059 hdr->size = size;
1060 hole = min_t(unsigned int, size - (proglen + sizeof(*hdr)),
1061 PAGE_SIZE - sizeof(*hdr));
1062 start = get_random_u32_below(hole) & ~(alignment - 1);
1063
1064 /* Leave a random number of instructions before BPF code. */
1065 *image_ptr = &hdr->image[start];
1066
1067 return hdr;
1068 }
1069
bpf_jit_binary_free(struct bpf_binary_header * hdr)1070 void bpf_jit_binary_free(struct bpf_binary_header *hdr)
1071 {
1072 u32 size = hdr->size;
1073
1074 bpf_jit_free_exec(hdr);
1075 bpf_jit_uncharge_modmem(size);
1076 }
1077
1078 /* Allocate jit binary from bpf_prog_pack allocator.
1079 * Since the allocated memory is RO+X, the JIT engine cannot write directly
1080 * to the memory. To solve this problem, a RW buffer is also allocated at
1081 * as the same time. The JIT engine should calculate offsets based on the
1082 * RO memory address, but write JITed program to the RW buffer. Once the
1083 * JIT engine finishes, it calls bpf_jit_binary_pack_finalize, which copies
1084 * the JITed program to the RO memory.
1085 */
1086 struct bpf_binary_header *
bpf_jit_binary_pack_alloc(unsigned int proglen,u8 ** image_ptr,unsigned int alignment,struct bpf_binary_header ** rw_header,u8 ** rw_image,bpf_jit_fill_hole_t bpf_fill_ill_insns)1087 bpf_jit_binary_pack_alloc(unsigned int proglen, u8 **image_ptr,
1088 unsigned int alignment,
1089 struct bpf_binary_header **rw_header,
1090 u8 **rw_image,
1091 bpf_jit_fill_hole_t bpf_fill_ill_insns)
1092 {
1093 struct bpf_binary_header *ro_header;
1094 u32 size, hole, start;
1095
1096 WARN_ON_ONCE(!is_power_of_2(alignment) ||
1097 alignment > BPF_IMAGE_ALIGNMENT);
1098
1099 /* add 16 bytes for a random section of illegal instructions */
1100 size = round_up(proglen + sizeof(*ro_header) + 16, BPF_PROG_CHUNK_SIZE);
1101
1102 if (bpf_jit_charge_modmem(size))
1103 return NULL;
1104 ro_header = bpf_prog_pack_alloc(size, bpf_fill_ill_insns);
1105 if (!ro_header) {
1106 bpf_jit_uncharge_modmem(size);
1107 return NULL;
1108 }
1109
1110 *rw_header = kvmalloc(size, GFP_KERNEL);
1111 if (!*rw_header) {
1112 bpf_arch_text_copy(&ro_header->size, &size, sizeof(size));
1113 bpf_prog_pack_free(ro_header);
1114 bpf_jit_uncharge_modmem(size);
1115 return NULL;
1116 }
1117
1118 /* Fill space with illegal/arch-dep instructions. */
1119 bpf_fill_ill_insns(*rw_header, size);
1120 (*rw_header)->size = size;
1121
1122 hole = min_t(unsigned int, size - (proglen + sizeof(*ro_header)),
1123 BPF_PROG_CHUNK_SIZE - sizeof(*ro_header));
1124 start = get_random_u32_below(hole) & ~(alignment - 1);
1125
1126 *image_ptr = &ro_header->image[start];
1127 *rw_image = &(*rw_header)->image[start];
1128
1129 return ro_header;
1130 }
1131
1132 /* Copy JITed text from rw_header to its final location, the ro_header. */
bpf_jit_binary_pack_finalize(struct bpf_prog * prog,struct bpf_binary_header * ro_header,struct bpf_binary_header * rw_header)1133 int bpf_jit_binary_pack_finalize(struct bpf_prog *prog,
1134 struct bpf_binary_header *ro_header,
1135 struct bpf_binary_header *rw_header)
1136 {
1137 void *ptr;
1138
1139 ptr = bpf_arch_text_copy(ro_header, rw_header, rw_header->size);
1140
1141 kvfree(rw_header);
1142
1143 if (IS_ERR(ptr)) {
1144 bpf_prog_pack_free(ro_header);
1145 return PTR_ERR(ptr);
1146 }
1147 return 0;
1148 }
1149
1150 /* bpf_jit_binary_pack_free is called in two different scenarios:
1151 * 1) when the program is freed after;
1152 * 2) when the JIT engine fails (before bpf_jit_binary_pack_finalize).
1153 * For case 2), we need to free both the RO memory and the RW buffer.
1154 *
1155 * bpf_jit_binary_pack_free requires proper ro_header->size. However,
1156 * bpf_jit_binary_pack_alloc does not set it. Therefore, ro_header->size
1157 * must be set with either bpf_jit_binary_pack_finalize (normal path) or
1158 * bpf_arch_text_copy (when jit fails).
1159 */
bpf_jit_binary_pack_free(struct bpf_binary_header * ro_header,struct bpf_binary_header * rw_header)1160 void bpf_jit_binary_pack_free(struct bpf_binary_header *ro_header,
1161 struct bpf_binary_header *rw_header)
1162 {
1163 u32 size = ro_header->size;
1164
1165 bpf_prog_pack_free(ro_header);
1166 kvfree(rw_header);
1167 bpf_jit_uncharge_modmem(size);
1168 }
1169
1170 struct bpf_binary_header *
bpf_jit_binary_pack_hdr(const struct bpf_prog * fp)1171 bpf_jit_binary_pack_hdr(const struct bpf_prog *fp)
1172 {
1173 unsigned long real_start = (unsigned long)fp->bpf_func;
1174 unsigned long addr;
1175
1176 addr = real_start & BPF_PROG_CHUNK_MASK;
1177 return (void *)addr;
1178 }
1179
1180 static inline struct bpf_binary_header *
bpf_jit_binary_hdr(const struct bpf_prog * fp)1181 bpf_jit_binary_hdr(const struct bpf_prog *fp)
1182 {
1183 unsigned long real_start = (unsigned long)fp->bpf_func;
1184 unsigned long addr;
1185
1186 addr = real_start & PAGE_MASK;
1187 return (void *)addr;
1188 }
1189
1190 /* This symbol is only overridden by archs that have different
1191 * requirements than the usual eBPF JITs, f.e. when they only
1192 * implement cBPF JIT, do not set images read-only, etc.
1193 */
bpf_jit_free(struct bpf_prog * fp)1194 void __weak bpf_jit_free(struct bpf_prog *fp)
1195 {
1196 if (fp->jited) {
1197 struct bpf_binary_header *hdr = bpf_jit_binary_hdr(fp);
1198
1199 bpf_jit_binary_free(hdr);
1200 WARN_ON_ONCE(!bpf_prog_kallsyms_verify_off(fp));
1201 }
1202
1203 bpf_prog_unlock_free(fp);
1204 }
1205
bpf_jit_get_func_addr(const struct bpf_prog * prog,const struct bpf_insn * insn,bool extra_pass,u64 * func_addr,bool * func_addr_fixed)1206 int bpf_jit_get_func_addr(const struct bpf_prog *prog,
1207 const struct bpf_insn *insn, bool extra_pass,
1208 u64 *func_addr, bool *func_addr_fixed)
1209 {
1210 s16 off = insn->off;
1211 s32 imm = insn->imm;
1212 u8 *addr;
1213 int err;
1214
1215 *func_addr_fixed = insn->src_reg != BPF_PSEUDO_CALL;
1216 if (!*func_addr_fixed) {
1217 /* Place-holder address till the last pass has collected
1218 * all addresses for JITed subprograms in which case we
1219 * can pick them up from prog->aux.
1220 */
1221 if (!extra_pass)
1222 addr = NULL;
1223 else if (prog->aux->func &&
1224 off >= 0 && off < prog->aux->func_cnt)
1225 addr = (u8 *)prog->aux->func[off]->bpf_func;
1226 else
1227 return -EINVAL;
1228 } else if (insn->src_reg == BPF_PSEUDO_KFUNC_CALL &&
1229 bpf_jit_supports_far_kfunc_call()) {
1230 err = bpf_get_kfunc_addr(prog, insn->imm, insn->off, &addr);
1231 if (err)
1232 return err;
1233 } else {
1234 /* Address of a BPF helper call. Since part of the core
1235 * kernel, it's always at a fixed location. __bpf_call_base
1236 * and the helper with imm relative to it are both in core
1237 * kernel.
1238 */
1239 addr = (u8 *)__bpf_call_base + imm;
1240 }
1241
1242 *func_addr = (unsigned long)addr;
1243 return 0;
1244 }
1245
bpf_jit_blind_insn(const struct bpf_insn * from,const struct bpf_insn * aux,struct bpf_insn * to_buff,bool emit_zext)1246 static int bpf_jit_blind_insn(const struct bpf_insn *from,
1247 const struct bpf_insn *aux,
1248 struct bpf_insn *to_buff,
1249 bool emit_zext)
1250 {
1251 struct bpf_insn *to = to_buff;
1252 u32 imm_rnd = get_random_u32();
1253 s16 off;
1254
1255 BUILD_BUG_ON(BPF_REG_AX + 1 != MAX_BPF_JIT_REG);
1256 BUILD_BUG_ON(MAX_BPF_REG + 1 != MAX_BPF_JIT_REG);
1257
1258 /* Constraints on AX register:
1259 *
1260 * AX register is inaccessible from user space. It is mapped in
1261 * all JITs, and used here for constant blinding rewrites. It is
1262 * typically "stateless" meaning its contents are only valid within
1263 * the executed instruction, but not across several instructions.
1264 * There are a few exceptions however which are further detailed
1265 * below.
1266 *
1267 * Constant blinding is only used by JITs, not in the interpreter.
1268 * The interpreter uses AX in some occasions as a local temporary
1269 * register e.g. in DIV or MOD instructions.
1270 *
1271 * In restricted circumstances, the verifier can also use the AX
1272 * register for rewrites as long as they do not interfere with
1273 * the above cases!
1274 */
1275 if (from->dst_reg == BPF_REG_AX || from->src_reg == BPF_REG_AX)
1276 goto out;
1277
1278 if (from->imm == 0 &&
1279 (from->code == (BPF_ALU | BPF_MOV | BPF_K) ||
1280 from->code == (BPF_ALU64 | BPF_MOV | BPF_K))) {
1281 *to++ = BPF_ALU64_REG(BPF_XOR, from->dst_reg, from->dst_reg);
1282 goto out;
1283 }
1284
1285 switch (from->code) {
1286 case BPF_ALU | BPF_ADD | BPF_K:
1287 case BPF_ALU | BPF_SUB | BPF_K:
1288 case BPF_ALU | BPF_AND | BPF_K:
1289 case BPF_ALU | BPF_OR | BPF_K:
1290 case BPF_ALU | BPF_XOR | BPF_K:
1291 case BPF_ALU | BPF_MUL | BPF_K:
1292 case BPF_ALU | BPF_MOV | BPF_K:
1293 case BPF_ALU | BPF_DIV | BPF_K:
1294 case BPF_ALU | BPF_MOD | BPF_K:
1295 *to++ = BPF_ALU32_IMM(BPF_MOV, BPF_REG_AX, imm_rnd ^ from->imm);
1296 *to++ = BPF_ALU32_IMM(BPF_XOR, BPF_REG_AX, imm_rnd);
1297 *to++ = BPF_ALU32_REG_OFF(from->code, from->dst_reg, BPF_REG_AX, from->off);
1298 break;
1299
1300 case BPF_ALU64 | BPF_ADD | BPF_K:
1301 case BPF_ALU64 | BPF_SUB | BPF_K:
1302 case BPF_ALU64 | BPF_AND | BPF_K:
1303 case BPF_ALU64 | BPF_OR | BPF_K:
1304 case BPF_ALU64 | BPF_XOR | BPF_K:
1305 case BPF_ALU64 | BPF_MUL | BPF_K:
1306 case BPF_ALU64 | BPF_MOV | BPF_K:
1307 case BPF_ALU64 | BPF_DIV | BPF_K:
1308 case BPF_ALU64 | BPF_MOD | BPF_K:
1309 *to++ = BPF_ALU64_IMM(BPF_MOV, BPF_REG_AX, imm_rnd ^ from->imm);
1310 *to++ = BPF_ALU64_IMM(BPF_XOR, BPF_REG_AX, imm_rnd);
1311 *to++ = BPF_ALU64_REG_OFF(from->code, from->dst_reg, BPF_REG_AX, from->off);
1312 break;
1313
1314 case BPF_JMP | BPF_JEQ | BPF_K:
1315 case BPF_JMP | BPF_JNE | BPF_K:
1316 case BPF_JMP | BPF_JGT | BPF_K:
1317 case BPF_JMP | BPF_JLT | BPF_K:
1318 case BPF_JMP | BPF_JGE | BPF_K:
1319 case BPF_JMP | BPF_JLE | BPF_K:
1320 case BPF_JMP | BPF_JSGT | BPF_K:
1321 case BPF_JMP | BPF_JSLT | BPF_K:
1322 case BPF_JMP | BPF_JSGE | BPF_K:
1323 case BPF_JMP | BPF_JSLE | BPF_K:
1324 case BPF_JMP | BPF_JSET | BPF_K:
1325 /* Accommodate for extra offset in case of a backjump. */
1326 off = from->off;
1327 if (off < 0)
1328 off -= 2;
1329 *to++ = BPF_ALU64_IMM(BPF_MOV, BPF_REG_AX, imm_rnd ^ from->imm);
1330 *to++ = BPF_ALU64_IMM(BPF_XOR, BPF_REG_AX, imm_rnd);
1331 *to++ = BPF_JMP_REG(from->code, from->dst_reg, BPF_REG_AX, off);
1332 break;
1333
1334 case BPF_JMP32 | BPF_JEQ | BPF_K:
1335 case BPF_JMP32 | BPF_JNE | BPF_K:
1336 case BPF_JMP32 | BPF_JGT | BPF_K:
1337 case BPF_JMP32 | BPF_JLT | BPF_K:
1338 case BPF_JMP32 | BPF_JGE | BPF_K:
1339 case BPF_JMP32 | BPF_JLE | BPF_K:
1340 case BPF_JMP32 | BPF_JSGT | BPF_K:
1341 case BPF_JMP32 | BPF_JSLT | BPF_K:
1342 case BPF_JMP32 | BPF_JSGE | BPF_K:
1343 case BPF_JMP32 | BPF_JSLE | BPF_K:
1344 case BPF_JMP32 | BPF_JSET | BPF_K:
1345 /* Accommodate for extra offset in case of a backjump. */
1346 off = from->off;
1347 if (off < 0)
1348 off -= 2;
1349 *to++ = BPF_ALU32_IMM(BPF_MOV, BPF_REG_AX, imm_rnd ^ from->imm);
1350 *to++ = BPF_ALU32_IMM(BPF_XOR, BPF_REG_AX, imm_rnd);
1351 *to++ = BPF_JMP32_REG(from->code, from->dst_reg, BPF_REG_AX,
1352 off);
1353 break;
1354
1355 case BPF_LD | BPF_IMM | BPF_DW:
1356 *to++ = BPF_ALU64_IMM(BPF_MOV, BPF_REG_AX, imm_rnd ^ aux[1].imm);
1357 *to++ = BPF_ALU64_IMM(BPF_XOR, BPF_REG_AX, imm_rnd);
1358 *to++ = BPF_ALU64_IMM(BPF_LSH, BPF_REG_AX, 32);
1359 *to++ = BPF_ALU64_REG(BPF_MOV, aux[0].dst_reg, BPF_REG_AX);
1360 break;
1361 case 0: /* Part 2 of BPF_LD | BPF_IMM | BPF_DW. */
1362 *to++ = BPF_ALU32_IMM(BPF_MOV, BPF_REG_AX, imm_rnd ^ aux[0].imm);
1363 *to++ = BPF_ALU32_IMM(BPF_XOR, BPF_REG_AX, imm_rnd);
1364 if (emit_zext)
1365 *to++ = BPF_ZEXT_REG(BPF_REG_AX);
1366 *to++ = BPF_ALU64_REG(BPF_OR, aux[0].dst_reg, BPF_REG_AX);
1367 break;
1368
1369 case BPF_ST | BPF_MEM | BPF_DW:
1370 case BPF_ST | BPF_MEM | BPF_W:
1371 case BPF_ST | BPF_MEM | BPF_H:
1372 case BPF_ST | BPF_MEM | BPF_B:
1373 *to++ = BPF_ALU64_IMM(BPF_MOV, BPF_REG_AX, imm_rnd ^ from->imm);
1374 *to++ = BPF_ALU64_IMM(BPF_XOR, BPF_REG_AX, imm_rnd);
1375 *to++ = BPF_STX_MEM(from->code, from->dst_reg, BPF_REG_AX, from->off);
1376 break;
1377 }
1378 out:
1379 return to - to_buff;
1380 }
1381
bpf_prog_clone_create(struct bpf_prog * fp_other,gfp_t gfp_extra_flags)1382 static struct bpf_prog *bpf_prog_clone_create(struct bpf_prog *fp_other,
1383 gfp_t gfp_extra_flags)
1384 {
1385 gfp_t gfp_flags = GFP_KERNEL | __GFP_ZERO | gfp_extra_flags;
1386 struct bpf_prog *fp;
1387
1388 fp = __vmalloc(fp_other->pages * PAGE_SIZE, gfp_flags);
1389 if (fp != NULL) {
1390 /* aux->prog still points to the fp_other one, so
1391 * when promoting the clone to the real program,
1392 * this still needs to be adapted.
1393 */
1394 memcpy(fp, fp_other, fp_other->pages * PAGE_SIZE);
1395 }
1396
1397 return fp;
1398 }
1399
bpf_prog_clone_free(struct bpf_prog * fp)1400 static void bpf_prog_clone_free(struct bpf_prog *fp)
1401 {
1402 /* aux was stolen by the other clone, so we cannot free
1403 * it from this path! It will be freed eventually by the
1404 * other program on release.
1405 *
1406 * At this point, we don't need a deferred release since
1407 * clone is guaranteed to not be locked.
1408 */
1409 fp->aux = NULL;
1410 fp->stats = NULL;
1411 fp->active = NULL;
1412 __bpf_prog_free(fp);
1413 }
1414
bpf_jit_prog_release_other(struct bpf_prog * fp,struct bpf_prog * fp_other)1415 void bpf_jit_prog_release_other(struct bpf_prog *fp, struct bpf_prog *fp_other)
1416 {
1417 /* We have to repoint aux->prog to self, as we don't
1418 * know whether fp here is the clone or the original.
1419 */
1420 fp->aux->prog = fp;
1421 bpf_prog_clone_free(fp_other);
1422 }
1423
bpf_jit_blind_constants(struct bpf_prog * prog)1424 struct bpf_prog *bpf_jit_blind_constants(struct bpf_prog *prog)
1425 {
1426 struct bpf_insn insn_buff[16], aux[2];
1427 struct bpf_prog *clone, *tmp;
1428 int insn_delta, insn_cnt;
1429 struct bpf_insn *insn;
1430 int i, rewritten;
1431
1432 if (!prog->blinding_requested || prog->blinded)
1433 return prog;
1434
1435 clone = bpf_prog_clone_create(prog, GFP_USER);
1436 if (!clone)
1437 return ERR_PTR(-ENOMEM);
1438
1439 insn_cnt = clone->len;
1440 insn = clone->insnsi;
1441
1442 for (i = 0; i < insn_cnt; i++, insn++) {
1443 if (bpf_pseudo_func(insn)) {
1444 /* ld_imm64 with an address of bpf subprog is not
1445 * a user controlled constant. Don't randomize it,
1446 * since it will conflict with jit_subprogs() logic.
1447 */
1448 insn++;
1449 i++;
1450 continue;
1451 }
1452
1453 /* We temporarily need to hold the original ld64 insn
1454 * so that we can still access the first part in the
1455 * second blinding run.
1456 */
1457 if (insn[0].code == (BPF_LD | BPF_IMM | BPF_DW) &&
1458 insn[1].code == 0)
1459 memcpy(aux, insn, sizeof(aux));
1460
1461 rewritten = bpf_jit_blind_insn(insn, aux, insn_buff,
1462 clone->aux->verifier_zext);
1463 if (!rewritten)
1464 continue;
1465
1466 tmp = bpf_patch_insn_single(clone, i, insn_buff, rewritten);
1467 if (IS_ERR(tmp)) {
1468 /* Patching may have repointed aux->prog during
1469 * realloc from the original one, so we need to
1470 * fix it up here on error.
1471 */
1472 bpf_jit_prog_release_other(prog, clone);
1473 return tmp;
1474 }
1475
1476 clone = tmp;
1477 insn_delta = rewritten - 1;
1478
1479 /* Walk new program and skip insns we just inserted. */
1480 insn = clone->insnsi + i + insn_delta;
1481 insn_cnt += insn_delta;
1482 i += insn_delta;
1483 }
1484
1485 clone->blinded = 1;
1486 return clone;
1487 }
1488 #endif /* CONFIG_BPF_JIT */
1489
1490 /* Base function for offset calculation. Needs to go into .text section,
1491 * therefore keeping it non-static as well; will also be used by JITs
1492 * anyway later on, so do not let the compiler omit it. This also needs
1493 * to go into kallsyms for correlation from e.g. bpftool, so naming
1494 * must not change.
1495 */
__bpf_call_base(u64 r1,u64 r2,u64 r3,u64 r4,u64 r5)1496 noinline u64 __bpf_call_base(u64 r1, u64 r2, u64 r3, u64 r4, u64 r5)
1497 {
1498 return 0;
1499 }
1500 EXPORT_SYMBOL_GPL(__bpf_call_base);
1501
1502 /* All UAPI available opcodes. */
1503 #define BPF_INSN_MAP(INSN_2, INSN_3) \
1504 /* 32 bit ALU operations. */ \
1505 /* Register based. */ \
1506 INSN_3(ALU, ADD, X), \
1507 INSN_3(ALU, SUB, X), \
1508 INSN_3(ALU, AND, X), \
1509 INSN_3(ALU, OR, X), \
1510 INSN_3(ALU, LSH, X), \
1511 INSN_3(ALU, RSH, X), \
1512 INSN_3(ALU, XOR, X), \
1513 INSN_3(ALU, MUL, X), \
1514 INSN_3(ALU, MOV, X), \
1515 INSN_3(ALU, ARSH, X), \
1516 INSN_3(ALU, DIV, X), \
1517 INSN_3(ALU, MOD, X), \
1518 INSN_2(ALU, NEG), \
1519 INSN_3(ALU, END, TO_BE), \
1520 INSN_3(ALU, END, TO_LE), \
1521 /* Immediate based. */ \
1522 INSN_3(ALU, ADD, K), \
1523 INSN_3(ALU, SUB, K), \
1524 INSN_3(ALU, AND, K), \
1525 INSN_3(ALU, OR, K), \
1526 INSN_3(ALU, LSH, K), \
1527 INSN_3(ALU, RSH, K), \
1528 INSN_3(ALU, XOR, K), \
1529 INSN_3(ALU, MUL, K), \
1530 INSN_3(ALU, MOV, K), \
1531 INSN_3(ALU, ARSH, K), \
1532 INSN_3(ALU, DIV, K), \
1533 INSN_3(ALU, MOD, K), \
1534 /* 64 bit ALU operations. */ \
1535 /* Register based. */ \
1536 INSN_3(ALU64, ADD, X), \
1537 INSN_3(ALU64, SUB, X), \
1538 INSN_3(ALU64, AND, X), \
1539 INSN_3(ALU64, OR, X), \
1540 INSN_3(ALU64, LSH, X), \
1541 INSN_3(ALU64, RSH, X), \
1542 INSN_3(ALU64, XOR, X), \
1543 INSN_3(ALU64, MUL, X), \
1544 INSN_3(ALU64, MOV, X), \
1545 INSN_3(ALU64, ARSH, X), \
1546 INSN_3(ALU64, DIV, X), \
1547 INSN_3(ALU64, MOD, X), \
1548 INSN_2(ALU64, NEG), \
1549 INSN_3(ALU64, END, TO_LE), \
1550 /* Immediate based. */ \
1551 INSN_3(ALU64, ADD, K), \
1552 INSN_3(ALU64, SUB, K), \
1553 INSN_3(ALU64, AND, K), \
1554 INSN_3(ALU64, OR, K), \
1555 INSN_3(ALU64, LSH, K), \
1556 INSN_3(ALU64, RSH, K), \
1557 INSN_3(ALU64, XOR, K), \
1558 INSN_3(ALU64, MUL, K), \
1559 INSN_3(ALU64, MOV, K), \
1560 INSN_3(ALU64, ARSH, K), \
1561 INSN_3(ALU64, DIV, K), \
1562 INSN_3(ALU64, MOD, K), \
1563 /* Call instruction. */ \
1564 INSN_2(JMP, CALL), \
1565 /* Exit instruction. */ \
1566 INSN_2(JMP, EXIT), \
1567 /* 32-bit Jump instructions. */ \
1568 /* Register based. */ \
1569 INSN_3(JMP32, JEQ, X), \
1570 INSN_3(JMP32, JNE, X), \
1571 INSN_3(JMP32, JGT, X), \
1572 INSN_3(JMP32, JLT, X), \
1573 INSN_3(JMP32, JGE, X), \
1574 INSN_3(JMP32, JLE, X), \
1575 INSN_3(JMP32, JSGT, X), \
1576 INSN_3(JMP32, JSLT, X), \
1577 INSN_3(JMP32, JSGE, X), \
1578 INSN_3(JMP32, JSLE, X), \
1579 INSN_3(JMP32, JSET, X), \
1580 /* Immediate based. */ \
1581 INSN_3(JMP32, JEQ, K), \
1582 INSN_3(JMP32, JNE, K), \
1583 INSN_3(JMP32, JGT, K), \
1584 INSN_3(JMP32, JLT, K), \
1585 INSN_3(JMP32, JGE, K), \
1586 INSN_3(JMP32, JLE, K), \
1587 INSN_3(JMP32, JSGT, K), \
1588 INSN_3(JMP32, JSLT, K), \
1589 INSN_3(JMP32, JSGE, K), \
1590 INSN_3(JMP32, JSLE, K), \
1591 INSN_3(JMP32, JSET, K), \
1592 /* Jump instructions. */ \
1593 /* Register based. */ \
1594 INSN_3(JMP, JEQ, X), \
1595 INSN_3(JMP, JNE, X), \
1596 INSN_3(JMP, JGT, X), \
1597 INSN_3(JMP, JLT, X), \
1598 INSN_3(JMP, JGE, X), \
1599 INSN_3(JMP, JLE, X), \
1600 INSN_3(JMP, JSGT, X), \
1601 INSN_3(JMP, JSLT, X), \
1602 INSN_3(JMP, JSGE, X), \
1603 INSN_3(JMP, JSLE, X), \
1604 INSN_3(JMP, JSET, X), \
1605 /* Immediate based. */ \
1606 INSN_3(JMP, JEQ, K), \
1607 INSN_3(JMP, JNE, K), \
1608 INSN_3(JMP, JGT, K), \
1609 INSN_3(JMP, JLT, K), \
1610 INSN_3(JMP, JGE, K), \
1611 INSN_3(JMP, JLE, K), \
1612 INSN_3(JMP, JSGT, K), \
1613 INSN_3(JMP, JSLT, K), \
1614 INSN_3(JMP, JSGE, K), \
1615 INSN_3(JMP, JSLE, K), \
1616 INSN_3(JMP, JSET, K), \
1617 INSN_2(JMP, JA), \
1618 INSN_2(JMP32, JA), \
1619 /* Store instructions. */ \
1620 /* Register based. */ \
1621 INSN_3(STX, MEM, B), \
1622 INSN_3(STX, MEM, H), \
1623 INSN_3(STX, MEM, W), \
1624 INSN_3(STX, MEM, DW), \
1625 INSN_3(STX, ATOMIC, W), \
1626 INSN_3(STX, ATOMIC, DW), \
1627 /* Immediate based. */ \
1628 INSN_3(ST, MEM, B), \
1629 INSN_3(ST, MEM, H), \
1630 INSN_3(ST, MEM, W), \
1631 INSN_3(ST, MEM, DW), \
1632 /* Load instructions. */ \
1633 /* Register based. */ \
1634 INSN_3(LDX, MEM, B), \
1635 INSN_3(LDX, MEM, H), \
1636 INSN_3(LDX, MEM, W), \
1637 INSN_3(LDX, MEM, DW), \
1638 INSN_3(LDX, MEMSX, B), \
1639 INSN_3(LDX, MEMSX, H), \
1640 INSN_3(LDX, MEMSX, W), \
1641 /* Immediate based. */ \
1642 INSN_3(LD, IMM, DW)
1643
bpf_opcode_in_insntable(u8 code)1644 bool bpf_opcode_in_insntable(u8 code)
1645 {
1646 #define BPF_INSN_2_TBL(x, y) [BPF_##x | BPF_##y] = true
1647 #define BPF_INSN_3_TBL(x, y, z) [BPF_##x | BPF_##y | BPF_##z] = true
1648 static const bool public_insntable[256] = {
1649 [0 ... 255] = false,
1650 /* Now overwrite non-defaults ... */
1651 BPF_INSN_MAP(BPF_INSN_2_TBL, BPF_INSN_3_TBL),
1652 /* UAPI exposed, but rewritten opcodes. cBPF carry-over. */
1653 [BPF_LD | BPF_ABS | BPF_B] = true,
1654 [BPF_LD | BPF_ABS | BPF_H] = true,
1655 [BPF_LD | BPF_ABS | BPF_W] = true,
1656 [BPF_LD | BPF_IND | BPF_B] = true,
1657 [BPF_LD | BPF_IND | BPF_H] = true,
1658 [BPF_LD | BPF_IND | BPF_W] = true,
1659 };
1660 #undef BPF_INSN_3_TBL
1661 #undef BPF_INSN_2_TBL
1662 return public_insntable[code];
1663 }
1664
1665 #ifndef CONFIG_BPF_JIT_ALWAYS_ON
1666 /**
1667 * ___bpf_prog_run - run eBPF program on a given context
1668 * @regs: is the array of MAX_BPF_EXT_REG eBPF pseudo-registers
1669 * @insn: is the array of eBPF instructions
1670 *
1671 * Decode and execute eBPF instructions.
1672 *
1673 * Return: whatever value is in %BPF_R0 at program exit
1674 */
___bpf_prog_run(u64 * regs,const struct bpf_insn * insn)1675 static u64 ___bpf_prog_run(u64 *regs, const struct bpf_insn *insn)
1676 {
1677 #define BPF_INSN_2_LBL(x, y) [BPF_##x | BPF_##y] = &&x##_##y
1678 #define BPF_INSN_3_LBL(x, y, z) [BPF_##x | BPF_##y | BPF_##z] = &&x##_##y##_##z
1679 static const void * const jumptable[256] __annotate_jump_table = {
1680 [0 ... 255] = &&default_label,
1681 /* Now overwrite non-defaults ... */
1682 BPF_INSN_MAP(BPF_INSN_2_LBL, BPF_INSN_3_LBL),
1683 /* Non-UAPI available opcodes. */
1684 [BPF_JMP | BPF_CALL_ARGS] = &&JMP_CALL_ARGS,
1685 [BPF_JMP | BPF_TAIL_CALL] = &&JMP_TAIL_CALL,
1686 [BPF_ST | BPF_NOSPEC] = &&ST_NOSPEC,
1687 [BPF_LDX | BPF_PROBE_MEM | BPF_B] = &&LDX_PROBE_MEM_B,
1688 [BPF_LDX | BPF_PROBE_MEM | BPF_H] = &&LDX_PROBE_MEM_H,
1689 [BPF_LDX | BPF_PROBE_MEM | BPF_W] = &&LDX_PROBE_MEM_W,
1690 [BPF_LDX | BPF_PROBE_MEM | BPF_DW] = &&LDX_PROBE_MEM_DW,
1691 [BPF_LDX | BPF_PROBE_MEMSX | BPF_B] = &&LDX_PROBE_MEMSX_B,
1692 [BPF_LDX | BPF_PROBE_MEMSX | BPF_H] = &&LDX_PROBE_MEMSX_H,
1693 [BPF_LDX | BPF_PROBE_MEMSX | BPF_W] = &&LDX_PROBE_MEMSX_W,
1694 };
1695 #undef BPF_INSN_3_LBL
1696 #undef BPF_INSN_2_LBL
1697 u32 tail_call_cnt = 0;
1698
1699 #define CONT ({ insn++; goto select_insn; })
1700 #define CONT_JMP ({ insn++; goto select_insn; })
1701
1702 select_insn:
1703 goto *jumptable[insn->code];
1704
1705 /* Explicitly mask the register-based shift amounts with 63 or 31
1706 * to avoid undefined behavior. Normally this won't affect the
1707 * generated code, for example, in case of native 64 bit archs such
1708 * as x86-64 or arm64, the compiler is optimizing the AND away for
1709 * the interpreter. In case of JITs, each of the JIT backends compiles
1710 * the BPF shift operations to machine instructions which produce
1711 * implementation-defined results in such a case; the resulting
1712 * contents of the register may be arbitrary, but program behaviour
1713 * as a whole remains defined. In other words, in case of JIT backends,
1714 * the AND must /not/ be added to the emitted LSH/RSH/ARSH translation.
1715 */
1716 /* ALU (shifts) */
1717 #define SHT(OPCODE, OP) \
1718 ALU64_##OPCODE##_X: \
1719 DST = DST OP (SRC & 63); \
1720 CONT; \
1721 ALU_##OPCODE##_X: \
1722 DST = (u32) DST OP ((u32) SRC & 31); \
1723 CONT; \
1724 ALU64_##OPCODE##_K: \
1725 DST = DST OP IMM; \
1726 CONT; \
1727 ALU_##OPCODE##_K: \
1728 DST = (u32) DST OP (u32) IMM; \
1729 CONT;
1730 /* ALU (rest) */
1731 #define ALU(OPCODE, OP) \
1732 ALU64_##OPCODE##_X: \
1733 DST = DST OP SRC; \
1734 CONT; \
1735 ALU_##OPCODE##_X: \
1736 DST = (u32) DST OP (u32) SRC; \
1737 CONT; \
1738 ALU64_##OPCODE##_K: \
1739 DST = DST OP IMM; \
1740 CONT; \
1741 ALU_##OPCODE##_K: \
1742 DST = (u32) DST OP (u32) IMM; \
1743 CONT;
1744 ALU(ADD, +)
1745 ALU(SUB, -)
1746 ALU(AND, &)
1747 ALU(OR, |)
1748 ALU(XOR, ^)
1749 ALU(MUL, *)
1750 SHT(LSH, <<)
1751 SHT(RSH, >>)
1752 #undef SHT
1753 #undef ALU
1754 ALU_NEG:
1755 DST = (u32) -DST;
1756 CONT;
1757 ALU64_NEG:
1758 DST = -DST;
1759 CONT;
1760 ALU_MOV_X:
1761 switch (OFF) {
1762 case 0:
1763 DST = (u32) SRC;
1764 break;
1765 case 8:
1766 DST = (u32)(s8) SRC;
1767 break;
1768 case 16:
1769 DST = (u32)(s16) SRC;
1770 break;
1771 }
1772 CONT;
1773 ALU_MOV_K:
1774 DST = (u32) IMM;
1775 CONT;
1776 ALU64_MOV_X:
1777 switch (OFF) {
1778 case 0:
1779 DST = SRC;
1780 break;
1781 case 8:
1782 DST = (s8) SRC;
1783 break;
1784 case 16:
1785 DST = (s16) SRC;
1786 break;
1787 case 32:
1788 DST = (s32) SRC;
1789 break;
1790 }
1791 CONT;
1792 ALU64_MOV_K:
1793 DST = IMM;
1794 CONT;
1795 LD_IMM_DW:
1796 DST = (u64) (u32) insn[0].imm | ((u64) (u32) insn[1].imm) << 32;
1797 insn++;
1798 CONT;
1799 ALU_ARSH_X:
1800 DST = (u64) (u32) (((s32) DST) >> (SRC & 31));
1801 CONT;
1802 ALU_ARSH_K:
1803 DST = (u64) (u32) (((s32) DST) >> IMM);
1804 CONT;
1805 ALU64_ARSH_X:
1806 (*(s64 *) &DST) >>= (SRC & 63);
1807 CONT;
1808 ALU64_ARSH_K:
1809 (*(s64 *) &DST) >>= IMM;
1810 CONT;
1811 ALU64_MOD_X:
1812 switch (OFF) {
1813 case 0:
1814 div64_u64_rem(DST, SRC, &AX);
1815 DST = AX;
1816 break;
1817 case 1:
1818 AX = div64_s64(DST, SRC);
1819 DST = DST - AX * SRC;
1820 break;
1821 }
1822 CONT;
1823 ALU_MOD_X:
1824 switch (OFF) {
1825 case 0:
1826 AX = (u32) DST;
1827 DST = do_div(AX, (u32) SRC);
1828 break;
1829 case 1:
1830 AX = abs((s32)DST);
1831 AX = do_div(AX, abs((s32)SRC));
1832 if ((s32)DST < 0)
1833 DST = (u32)-AX;
1834 else
1835 DST = (u32)AX;
1836 break;
1837 }
1838 CONT;
1839 ALU64_MOD_K:
1840 switch (OFF) {
1841 case 0:
1842 div64_u64_rem(DST, IMM, &AX);
1843 DST = AX;
1844 break;
1845 case 1:
1846 AX = div64_s64(DST, IMM);
1847 DST = DST - AX * IMM;
1848 break;
1849 }
1850 CONT;
1851 ALU_MOD_K:
1852 switch (OFF) {
1853 case 0:
1854 AX = (u32) DST;
1855 DST = do_div(AX, (u32) IMM);
1856 break;
1857 case 1:
1858 AX = abs((s32)DST);
1859 AX = do_div(AX, abs((s32)IMM));
1860 if ((s32)DST < 0)
1861 DST = (u32)-AX;
1862 else
1863 DST = (u32)AX;
1864 break;
1865 }
1866 CONT;
1867 ALU64_DIV_X:
1868 switch (OFF) {
1869 case 0:
1870 DST = div64_u64(DST, SRC);
1871 break;
1872 case 1:
1873 DST = div64_s64(DST, SRC);
1874 break;
1875 }
1876 CONT;
1877 ALU_DIV_X:
1878 switch (OFF) {
1879 case 0:
1880 AX = (u32) DST;
1881 do_div(AX, (u32) SRC);
1882 DST = (u32) AX;
1883 break;
1884 case 1:
1885 AX = abs((s32)DST);
1886 do_div(AX, abs((s32)SRC));
1887 if (((s32)DST < 0) == ((s32)SRC < 0))
1888 DST = (u32)AX;
1889 else
1890 DST = (u32)-AX;
1891 break;
1892 }
1893 CONT;
1894 ALU64_DIV_K:
1895 switch (OFF) {
1896 case 0:
1897 DST = div64_u64(DST, IMM);
1898 break;
1899 case 1:
1900 DST = div64_s64(DST, IMM);
1901 break;
1902 }
1903 CONT;
1904 ALU_DIV_K:
1905 switch (OFF) {
1906 case 0:
1907 AX = (u32) DST;
1908 do_div(AX, (u32) IMM);
1909 DST = (u32) AX;
1910 break;
1911 case 1:
1912 AX = abs((s32)DST);
1913 do_div(AX, abs((s32)IMM));
1914 if (((s32)DST < 0) == ((s32)IMM < 0))
1915 DST = (u32)AX;
1916 else
1917 DST = (u32)-AX;
1918 break;
1919 }
1920 CONT;
1921 ALU_END_TO_BE:
1922 switch (IMM) {
1923 case 16:
1924 DST = (__force u16) cpu_to_be16(DST);
1925 break;
1926 case 32:
1927 DST = (__force u32) cpu_to_be32(DST);
1928 break;
1929 case 64:
1930 DST = (__force u64) cpu_to_be64(DST);
1931 break;
1932 }
1933 CONT;
1934 ALU_END_TO_LE:
1935 switch (IMM) {
1936 case 16:
1937 DST = (__force u16) cpu_to_le16(DST);
1938 break;
1939 case 32:
1940 DST = (__force u32) cpu_to_le32(DST);
1941 break;
1942 case 64:
1943 DST = (__force u64) cpu_to_le64(DST);
1944 break;
1945 }
1946 CONT;
1947 ALU64_END_TO_LE:
1948 switch (IMM) {
1949 case 16:
1950 DST = (__force u16) __swab16(DST);
1951 break;
1952 case 32:
1953 DST = (__force u32) __swab32(DST);
1954 break;
1955 case 64:
1956 DST = (__force u64) __swab64(DST);
1957 break;
1958 }
1959 CONT;
1960
1961 /* CALL */
1962 JMP_CALL:
1963 /* Function call scratches BPF_R1-BPF_R5 registers,
1964 * preserves BPF_R6-BPF_R9, and stores return value
1965 * into BPF_R0.
1966 */
1967 BPF_R0 = (__bpf_call_base + insn->imm)(BPF_R1, BPF_R2, BPF_R3,
1968 BPF_R4, BPF_R5);
1969 CONT;
1970
1971 JMP_CALL_ARGS:
1972 BPF_R0 = (__bpf_call_base_args + insn->imm)(BPF_R1, BPF_R2,
1973 BPF_R3, BPF_R4,
1974 BPF_R5,
1975 insn + insn->off + 1);
1976 CONT;
1977
1978 JMP_TAIL_CALL: {
1979 struct bpf_map *map = (struct bpf_map *) (unsigned long) BPF_R2;
1980 struct bpf_array *array = container_of(map, struct bpf_array, map);
1981 struct bpf_prog *prog;
1982 u32 index = BPF_R3;
1983
1984 if (unlikely(index >= array->map.max_entries))
1985 goto out;
1986
1987 if (unlikely(tail_call_cnt >= MAX_TAIL_CALL_CNT))
1988 goto out;
1989
1990 tail_call_cnt++;
1991
1992 prog = READ_ONCE(array->ptrs[index]);
1993 if (!prog)
1994 goto out;
1995
1996 /* ARG1 at this point is guaranteed to point to CTX from
1997 * the verifier side due to the fact that the tail call is
1998 * handled like a helper, that is, bpf_tail_call_proto,
1999 * where arg1_type is ARG_PTR_TO_CTX.
2000 */
2001 insn = prog->insnsi;
2002 goto select_insn;
2003 out:
2004 CONT;
2005 }
2006 JMP_JA:
2007 insn += insn->off;
2008 CONT;
2009 JMP32_JA:
2010 insn += insn->imm;
2011 CONT;
2012 JMP_EXIT:
2013 return BPF_R0;
2014 /* JMP */
2015 #define COND_JMP(SIGN, OPCODE, CMP_OP) \
2016 JMP_##OPCODE##_X: \
2017 if ((SIGN##64) DST CMP_OP (SIGN##64) SRC) { \
2018 insn += insn->off; \
2019 CONT_JMP; \
2020 } \
2021 CONT; \
2022 JMP32_##OPCODE##_X: \
2023 if ((SIGN##32) DST CMP_OP (SIGN##32) SRC) { \
2024 insn += insn->off; \
2025 CONT_JMP; \
2026 } \
2027 CONT; \
2028 JMP_##OPCODE##_K: \
2029 if ((SIGN##64) DST CMP_OP (SIGN##64) IMM) { \
2030 insn += insn->off; \
2031 CONT_JMP; \
2032 } \
2033 CONT; \
2034 JMP32_##OPCODE##_K: \
2035 if ((SIGN##32) DST CMP_OP (SIGN##32) IMM) { \
2036 insn += insn->off; \
2037 CONT_JMP; \
2038 } \
2039 CONT;
2040 COND_JMP(u, JEQ, ==)
2041 COND_JMP(u, JNE, !=)
2042 COND_JMP(u, JGT, >)
2043 COND_JMP(u, JLT, <)
2044 COND_JMP(u, JGE, >=)
2045 COND_JMP(u, JLE, <=)
2046 COND_JMP(u, JSET, &)
2047 COND_JMP(s, JSGT, >)
2048 COND_JMP(s, JSLT, <)
2049 COND_JMP(s, JSGE, >=)
2050 COND_JMP(s, JSLE, <=)
2051 #undef COND_JMP
2052 /* ST, STX and LDX*/
2053 ST_NOSPEC:
2054 /* Speculation barrier for mitigating Speculative Store Bypass.
2055 * In case of arm64, we rely on the firmware mitigation as
2056 * controlled via the ssbd kernel parameter. Whenever the
2057 * mitigation is enabled, it works for all of the kernel code
2058 * with no need to provide any additional instructions here.
2059 * In case of x86, we use 'lfence' insn for mitigation. We
2060 * reuse preexisting logic from Spectre v1 mitigation that
2061 * happens to produce the required code on x86 for v4 as well.
2062 */
2063 barrier_nospec();
2064 CONT;
2065 #define LDST(SIZEOP, SIZE) \
2066 STX_MEM_##SIZEOP: \
2067 *(SIZE *)(unsigned long) (DST + insn->off) = SRC; \
2068 CONT; \
2069 ST_MEM_##SIZEOP: \
2070 *(SIZE *)(unsigned long) (DST + insn->off) = IMM; \
2071 CONT; \
2072 LDX_MEM_##SIZEOP: \
2073 DST = *(SIZE *)(unsigned long) (SRC + insn->off); \
2074 CONT; \
2075 LDX_PROBE_MEM_##SIZEOP: \
2076 bpf_probe_read_kernel_common(&DST, sizeof(SIZE), \
2077 (const void *)(long) (SRC + insn->off)); \
2078 DST = *((SIZE *)&DST); \
2079 CONT;
2080
2081 LDST(B, u8)
2082 LDST(H, u16)
2083 LDST(W, u32)
2084 LDST(DW, u64)
2085 #undef LDST
2086
2087 #define LDSX(SIZEOP, SIZE) \
2088 LDX_MEMSX_##SIZEOP: \
2089 DST = *(SIZE *)(unsigned long) (SRC + insn->off); \
2090 CONT; \
2091 LDX_PROBE_MEMSX_##SIZEOP: \
2092 bpf_probe_read_kernel_common(&DST, sizeof(SIZE), \
2093 (const void *)(long) (SRC + insn->off)); \
2094 DST = *((SIZE *)&DST); \
2095 CONT;
2096
2097 LDSX(B, s8)
2098 LDSX(H, s16)
2099 LDSX(W, s32)
2100 #undef LDSX
2101
2102 #define ATOMIC_ALU_OP(BOP, KOP) \
2103 case BOP: \
2104 if (BPF_SIZE(insn->code) == BPF_W) \
2105 atomic_##KOP((u32) SRC, (atomic_t *)(unsigned long) \
2106 (DST + insn->off)); \
2107 else \
2108 atomic64_##KOP((u64) SRC, (atomic64_t *)(unsigned long) \
2109 (DST + insn->off)); \
2110 break; \
2111 case BOP | BPF_FETCH: \
2112 if (BPF_SIZE(insn->code) == BPF_W) \
2113 SRC = (u32) atomic_fetch_##KOP( \
2114 (u32) SRC, \
2115 (atomic_t *)(unsigned long) (DST + insn->off)); \
2116 else \
2117 SRC = (u64) atomic64_fetch_##KOP( \
2118 (u64) SRC, \
2119 (atomic64_t *)(unsigned long) (DST + insn->off)); \
2120 break;
2121
2122 STX_ATOMIC_DW:
2123 STX_ATOMIC_W:
2124 switch (IMM) {
2125 ATOMIC_ALU_OP(BPF_ADD, add)
2126 ATOMIC_ALU_OP(BPF_AND, and)
2127 ATOMIC_ALU_OP(BPF_OR, or)
2128 ATOMIC_ALU_OP(BPF_XOR, xor)
2129 #undef ATOMIC_ALU_OP
2130
2131 case BPF_XCHG:
2132 if (BPF_SIZE(insn->code) == BPF_W)
2133 SRC = (u32) atomic_xchg(
2134 (atomic_t *)(unsigned long) (DST + insn->off),
2135 (u32) SRC);
2136 else
2137 SRC = (u64) atomic64_xchg(
2138 (atomic64_t *)(unsigned long) (DST + insn->off),
2139 (u64) SRC);
2140 break;
2141 case BPF_CMPXCHG:
2142 if (BPF_SIZE(insn->code) == BPF_W)
2143 BPF_R0 = (u32) atomic_cmpxchg(
2144 (atomic_t *)(unsigned long) (DST + insn->off),
2145 (u32) BPF_R0, (u32) SRC);
2146 else
2147 BPF_R0 = (u64) atomic64_cmpxchg(
2148 (atomic64_t *)(unsigned long) (DST + insn->off),
2149 (u64) BPF_R0, (u64) SRC);
2150 break;
2151
2152 default:
2153 goto default_label;
2154 }
2155 CONT;
2156
2157 default_label:
2158 /* If we ever reach this, we have a bug somewhere. Die hard here
2159 * instead of just returning 0; we could be somewhere in a subprog,
2160 * so execution could continue otherwise which we do /not/ want.
2161 *
2162 * Note, verifier whitelists all opcodes in bpf_opcode_in_insntable().
2163 */
2164 pr_warn("BPF interpreter: unknown opcode %02x (imm: 0x%x)\n",
2165 insn->code, insn->imm);
2166 BUG_ON(1);
2167 return 0;
2168 }
2169
2170 #define PROG_NAME(stack_size) __bpf_prog_run##stack_size
2171 #define DEFINE_BPF_PROG_RUN(stack_size) \
2172 static unsigned int PROG_NAME(stack_size)(const void *ctx, const struct bpf_insn *insn) \
2173 { \
2174 u64 stack[stack_size / sizeof(u64)]; \
2175 u64 regs[MAX_BPF_EXT_REG] = {}; \
2176 \
2177 kmsan_unpoison_memory(stack, sizeof(stack)); \
2178 FP = (u64) (unsigned long) &stack[ARRAY_SIZE(stack)]; \
2179 ARG1 = (u64) (unsigned long) ctx; \
2180 return ___bpf_prog_run(regs, insn); \
2181 }
2182
2183 #define PROG_NAME_ARGS(stack_size) __bpf_prog_run_args##stack_size
2184 #define DEFINE_BPF_PROG_RUN_ARGS(stack_size) \
2185 static u64 PROG_NAME_ARGS(stack_size)(u64 r1, u64 r2, u64 r3, u64 r4, u64 r5, \
2186 const struct bpf_insn *insn) \
2187 { \
2188 u64 stack[stack_size / sizeof(u64)]; \
2189 u64 regs[MAX_BPF_EXT_REG]; \
2190 \
2191 kmsan_unpoison_memory(stack, sizeof(stack)); \
2192 FP = (u64) (unsigned long) &stack[ARRAY_SIZE(stack)]; \
2193 BPF_R1 = r1; \
2194 BPF_R2 = r2; \
2195 BPF_R3 = r3; \
2196 BPF_R4 = r4; \
2197 BPF_R5 = r5; \
2198 return ___bpf_prog_run(regs, insn); \
2199 }
2200
2201 #define EVAL1(FN, X) FN(X)
2202 #define EVAL2(FN, X, Y...) FN(X) EVAL1(FN, Y)
2203 #define EVAL3(FN, X, Y...) FN(X) EVAL2(FN, Y)
2204 #define EVAL4(FN, X, Y...) FN(X) EVAL3(FN, Y)
2205 #define EVAL5(FN, X, Y...) FN(X) EVAL4(FN, Y)
2206 #define EVAL6(FN, X, Y...) FN(X) EVAL5(FN, Y)
2207
2208 EVAL6(DEFINE_BPF_PROG_RUN, 32, 64, 96, 128, 160, 192);
2209 EVAL6(DEFINE_BPF_PROG_RUN, 224, 256, 288, 320, 352, 384);
2210 EVAL4(DEFINE_BPF_PROG_RUN, 416, 448, 480, 512);
2211
2212 EVAL6(DEFINE_BPF_PROG_RUN_ARGS, 32, 64, 96, 128, 160, 192);
2213 EVAL6(DEFINE_BPF_PROG_RUN_ARGS, 224, 256, 288, 320, 352, 384);
2214 EVAL4(DEFINE_BPF_PROG_RUN_ARGS, 416, 448, 480, 512);
2215
2216 #define PROG_NAME_LIST(stack_size) PROG_NAME(stack_size),
2217
2218 static unsigned int (*interpreters[])(const void *ctx,
2219 const struct bpf_insn *insn) = {
2220 EVAL6(PROG_NAME_LIST, 32, 64, 96, 128, 160, 192)
2221 EVAL6(PROG_NAME_LIST, 224, 256, 288, 320, 352, 384)
2222 EVAL4(PROG_NAME_LIST, 416, 448, 480, 512)
2223 };
2224 #undef PROG_NAME_LIST
2225 #define PROG_NAME_LIST(stack_size) PROG_NAME_ARGS(stack_size),
2226 static __maybe_unused
2227 u64 (*interpreters_args[])(u64 r1, u64 r2, u64 r3, u64 r4, u64 r5,
2228 const struct bpf_insn *insn) = {
2229 EVAL6(PROG_NAME_LIST, 32, 64, 96, 128, 160, 192)
2230 EVAL6(PROG_NAME_LIST, 224, 256, 288, 320, 352, 384)
2231 EVAL4(PROG_NAME_LIST, 416, 448, 480, 512)
2232 };
2233 #undef PROG_NAME_LIST
2234
2235 #ifdef CONFIG_BPF_SYSCALL
bpf_patch_call_args(struct bpf_insn * insn,u32 stack_depth)2236 void bpf_patch_call_args(struct bpf_insn *insn, u32 stack_depth)
2237 {
2238 stack_depth = max_t(u32, stack_depth, 1);
2239 insn->off = (s16) insn->imm;
2240 insn->imm = interpreters_args[(round_up(stack_depth, 32) / 32) - 1] -
2241 __bpf_call_base_args;
2242 insn->code = BPF_JMP | BPF_CALL_ARGS;
2243 }
2244 #endif
2245 #else
__bpf_prog_ret0_warn(const void * ctx,const struct bpf_insn * insn)2246 static unsigned int __bpf_prog_ret0_warn(const void *ctx,
2247 const struct bpf_insn *insn)
2248 {
2249 /* If this handler ever gets executed, then BPF_JIT_ALWAYS_ON
2250 * is not working properly, so warn about it!
2251 */
2252 WARN_ON_ONCE(1);
2253 return 0;
2254 }
2255 #endif
2256
bpf_prog_map_compatible(struct bpf_map * map,const struct bpf_prog * fp)2257 bool bpf_prog_map_compatible(struct bpf_map *map,
2258 const struct bpf_prog *fp)
2259 {
2260 enum bpf_prog_type prog_type = resolve_prog_type(fp);
2261 bool ret;
2262 struct bpf_prog_aux *aux = fp->aux;
2263
2264 if (fp->kprobe_override)
2265 return false;
2266
2267 /* XDP programs inserted into maps are not guaranteed to run on
2268 * a particular netdev (and can run outside driver context entirely
2269 * in the case of devmap and cpumap). Until device checks
2270 * are implemented, prohibit adding dev-bound programs to program maps.
2271 */
2272 if (bpf_prog_is_dev_bound(aux))
2273 return false;
2274
2275 spin_lock(&map->owner.lock);
2276 if (!map->owner.type) {
2277 /* There's no owner yet where we could check for
2278 * compatibility.
2279 */
2280 map->owner.type = prog_type;
2281 map->owner.jited = fp->jited;
2282 map->owner.xdp_has_frags = aux->xdp_has_frags;
2283 map->owner.attach_func_proto = aux->attach_func_proto;
2284 ret = true;
2285 } else {
2286 ret = map->owner.type == prog_type &&
2287 map->owner.jited == fp->jited &&
2288 map->owner.xdp_has_frags == aux->xdp_has_frags;
2289 if (ret &&
2290 map->owner.attach_func_proto != aux->attach_func_proto) {
2291 switch (prog_type) {
2292 case BPF_PROG_TYPE_TRACING:
2293 case BPF_PROG_TYPE_LSM:
2294 case BPF_PROG_TYPE_EXT:
2295 case BPF_PROG_TYPE_STRUCT_OPS:
2296 ret = false;
2297 break;
2298 default:
2299 break;
2300 }
2301 }
2302 }
2303 spin_unlock(&map->owner.lock);
2304
2305 return ret;
2306 }
2307
bpf_check_tail_call(const struct bpf_prog * fp)2308 static int bpf_check_tail_call(const struct bpf_prog *fp)
2309 {
2310 struct bpf_prog_aux *aux = fp->aux;
2311 int i, ret = 0;
2312
2313 mutex_lock(&aux->used_maps_mutex);
2314 for (i = 0; i < aux->used_map_cnt; i++) {
2315 struct bpf_map *map = aux->used_maps[i];
2316
2317 if (!map_type_contains_progs(map))
2318 continue;
2319
2320 if (!bpf_prog_map_compatible(map, fp)) {
2321 ret = -EINVAL;
2322 goto out;
2323 }
2324 }
2325
2326 out:
2327 mutex_unlock(&aux->used_maps_mutex);
2328 return ret;
2329 }
2330
bpf_prog_select_func(struct bpf_prog * fp)2331 static void bpf_prog_select_func(struct bpf_prog *fp)
2332 {
2333 #ifndef CONFIG_BPF_JIT_ALWAYS_ON
2334 u32 stack_depth = max_t(u32, fp->aux->stack_depth, 1);
2335
2336 fp->bpf_func = interpreters[(round_up(stack_depth, 32) / 32) - 1];
2337 #else
2338 fp->bpf_func = __bpf_prog_ret0_warn;
2339 #endif
2340 }
2341
2342 /**
2343 * bpf_prog_select_runtime - select exec runtime for BPF program
2344 * @fp: bpf_prog populated with BPF program
2345 * @err: pointer to error variable
2346 *
2347 * Try to JIT eBPF program, if JIT is not available, use interpreter.
2348 * The BPF program will be executed via bpf_prog_run() function.
2349 *
2350 * Return: the &fp argument along with &err set to 0 for success or
2351 * a negative errno code on failure
2352 */
bpf_prog_select_runtime(struct bpf_prog * fp,int * err)2353 struct bpf_prog *bpf_prog_select_runtime(struct bpf_prog *fp, int *err)
2354 {
2355 /* In case of BPF to BPF calls, verifier did all the prep
2356 * work with regards to JITing, etc.
2357 */
2358 bool jit_needed = false;
2359
2360 if (fp->bpf_func)
2361 goto finalize;
2362
2363 if (IS_ENABLED(CONFIG_BPF_JIT_ALWAYS_ON) ||
2364 bpf_prog_has_kfunc_call(fp))
2365 jit_needed = true;
2366
2367 bpf_prog_select_func(fp);
2368
2369 /* eBPF JITs can rewrite the program in case constant
2370 * blinding is active. However, in case of error during
2371 * blinding, bpf_int_jit_compile() must always return a
2372 * valid program, which in this case would simply not
2373 * be JITed, but falls back to the interpreter.
2374 */
2375 if (!bpf_prog_is_offloaded(fp->aux)) {
2376 *err = bpf_prog_alloc_jited_linfo(fp);
2377 if (*err)
2378 return fp;
2379
2380 fp = bpf_int_jit_compile(fp);
2381 bpf_prog_jit_attempt_done(fp);
2382 if (!fp->jited && jit_needed) {
2383 *err = -ENOTSUPP;
2384 return fp;
2385 }
2386 } else {
2387 *err = bpf_prog_offload_compile(fp);
2388 if (*err)
2389 return fp;
2390 }
2391
2392 finalize:
2393 bpf_prog_lock_ro(fp);
2394
2395 /* The tail call compatibility check can only be done at
2396 * this late stage as we need to determine, if we deal
2397 * with JITed or non JITed program concatenations and not
2398 * all eBPF JITs might immediately support all features.
2399 */
2400 *err = bpf_check_tail_call(fp);
2401
2402 return fp;
2403 }
2404 EXPORT_SYMBOL_GPL(bpf_prog_select_runtime);
2405
__bpf_prog_ret1(const void * ctx,const struct bpf_insn * insn)2406 static unsigned int __bpf_prog_ret1(const void *ctx,
2407 const struct bpf_insn *insn)
2408 {
2409 return 1;
2410 }
2411
2412 static struct bpf_prog_dummy {
2413 struct bpf_prog prog;
2414 } dummy_bpf_prog = {
2415 .prog = {
2416 .bpf_func = __bpf_prog_ret1,
2417 },
2418 };
2419
2420 struct bpf_empty_prog_array bpf_empty_prog_array = {
2421 .null_prog = NULL,
2422 };
2423 EXPORT_SYMBOL(bpf_empty_prog_array);
2424
bpf_prog_array_alloc(u32 prog_cnt,gfp_t flags)2425 struct bpf_prog_array *bpf_prog_array_alloc(u32 prog_cnt, gfp_t flags)
2426 {
2427 if (prog_cnt)
2428 return kzalloc(sizeof(struct bpf_prog_array) +
2429 sizeof(struct bpf_prog_array_item) *
2430 (prog_cnt + 1),
2431 flags);
2432
2433 return &bpf_empty_prog_array.hdr;
2434 }
2435
bpf_prog_array_free(struct bpf_prog_array * progs)2436 void bpf_prog_array_free(struct bpf_prog_array *progs)
2437 {
2438 if (!progs || progs == &bpf_empty_prog_array.hdr)
2439 return;
2440 kfree_rcu(progs, rcu);
2441 }
2442
__bpf_prog_array_free_sleepable_cb(struct rcu_head * rcu)2443 static void __bpf_prog_array_free_sleepable_cb(struct rcu_head *rcu)
2444 {
2445 struct bpf_prog_array *progs;
2446
2447 /* If RCU Tasks Trace grace period implies RCU grace period, there is
2448 * no need to call kfree_rcu(), just call kfree() directly.
2449 */
2450 progs = container_of(rcu, struct bpf_prog_array, rcu);
2451 if (rcu_trace_implies_rcu_gp())
2452 kfree(progs);
2453 else
2454 kfree_rcu(progs, rcu);
2455 }
2456
bpf_prog_array_free_sleepable(struct bpf_prog_array * progs)2457 void bpf_prog_array_free_sleepable(struct bpf_prog_array *progs)
2458 {
2459 if (!progs || progs == &bpf_empty_prog_array.hdr)
2460 return;
2461 call_rcu_tasks_trace(&progs->rcu, __bpf_prog_array_free_sleepable_cb);
2462 }
2463
bpf_prog_array_length(struct bpf_prog_array * array)2464 int bpf_prog_array_length(struct bpf_prog_array *array)
2465 {
2466 struct bpf_prog_array_item *item;
2467 u32 cnt = 0;
2468
2469 for (item = array->items; item->prog; item++)
2470 if (item->prog != &dummy_bpf_prog.prog)
2471 cnt++;
2472 return cnt;
2473 }
2474
bpf_prog_array_is_empty(struct bpf_prog_array * array)2475 bool bpf_prog_array_is_empty(struct bpf_prog_array *array)
2476 {
2477 struct bpf_prog_array_item *item;
2478
2479 for (item = array->items; item->prog; item++)
2480 if (item->prog != &dummy_bpf_prog.prog)
2481 return false;
2482 return true;
2483 }
2484
bpf_prog_array_copy_core(struct bpf_prog_array * array,u32 * prog_ids,u32 request_cnt)2485 static bool bpf_prog_array_copy_core(struct bpf_prog_array *array,
2486 u32 *prog_ids,
2487 u32 request_cnt)
2488 {
2489 struct bpf_prog_array_item *item;
2490 int i = 0;
2491
2492 for (item = array->items; item->prog; item++) {
2493 if (item->prog == &dummy_bpf_prog.prog)
2494 continue;
2495 prog_ids[i] = item->prog->aux->id;
2496 if (++i == request_cnt) {
2497 item++;
2498 break;
2499 }
2500 }
2501
2502 return !!(item->prog);
2503 }
2504
bpf_prog_array_copy_to_user(struct bpf_prog_array * array,__u32 __user * prog_ids,u32 cnt)2505 int bpf_prog_array_copy_to_user(struct bpf_prog_array *array,
2506 __u32 __user *prog_ids, u32 cnt)
2507 {
2508 unsigned long err = 0;
2509 bool nospc;
2510 u32 *ids;
2511
2512 /* users of this function are doing:
2513 * cnt = bpf_prog_array_length();
2514 * if (cnt > 0)
2515 * bpf_prog_array_copy_to_user(..., cnt);
2516 * so below kcalloc doesn't need extra cnt > 0 check.
2517 */
2518 ids = kcalloc(cnt, sizeof(u32), GFP_USER | __GFP_NOWARN);
2519 if (!ids)
2520 return -ENOMEM;
2521 nospc = bpf_prog_array_copy_core(array, ids, cnt);
2522 err = copy_to_user(prog_ids, ids, cnt * sizeof(u32));
2523 kfree(ids);
2524 if (err)
2525 return -EFAULT;
2526 if (nospc)
2527 return -ENOSPC;
2528 return 0;
2529 }
2530
bpf_prog_array_delete_safe(struct bpf_prog_array * array,struct bpf_prog * old_prog)2531 void bpf_prog_array_delete_safe(struct bpf_prog_array *array,
2532 struct bpf_prog *old_prog)
2533 {
2534 struct bpf_prog_array_item *item;
2535
2536 for (item = array->items; item->prog; item++)
2537 if (item->prog == old_prog) {
2538 WRITE_ONCE(item->prog, &dummy_bpf_prog.prog);
2539 break;
2540 }
2541 }
2542
2543 /**
2544 * bpf_prog_array_delete_safe_at() - Replaces the program at the given
2545 * index into the program array with
2546 * a dummy no-op program.
2547 * @array: a bpf_prog_array
2548 * @index: the index of the program to replace
2549 *
2550 * Skips over dummy programs, by not counting them, when calculating
2551 * the position of the program to replace.
2552 *
2553 * Return:
2554 * * 0 - Success
2555 * * -EINVAL - Invalid index value. Must be a non-negative integer.
2556 * * -ENOENT - Index out of range
2557 */
bpf_prog_array_delete_safe_at(struct bpf_prog_array * array,int index)2558 int bpf_prog_array_delete_safe_at(struct bpf_prog_array *array, int index)
2559 {
2560 return bpf_prog_array_update_at(array, index, &dummy_bpf_prog.prog);
2561 }
2562
2563 /**
2564 * bpf_prog_array_update_at() - Updates the program at the given index
2565 * into the program array.
2566 * @array: a bpf_prog_array
2567 * @index: the index of the program to update
2568 * @prog: the program to insert into the array
2569 *
2570 * Skips over dummy programs, by not counting them, when calculating
2571 * the position of the program to update.
2572 *
2573 * Return:
2574 * * 0 - Success
2575 * * -EINVAL - Invalid index value. Must be a non-negative integer.
2576 * * -ENOENT - Index out of range
2577 */
bpf_prog_array_update_at(struct bpf_prog_array * array,int index,struct bpf_prog * prog)2578 int bpf_prog_array_update_at(struct bpf_prog_array *array, int index,
2579 struct bpf_prog *prog)
2580 {
2581 struct bpf_prog_array_item *item;
2582
2583 if (unlikely(index < 0))
2584 return -EINVAL;
2585
2586 for (item = array->items; item->prog; item++) {
2587 if (item->prog == &dummy_bpf_prog.prog)
2588 continue;
2589 if (!index) {
2590 WRITE_ONCE(item->prog, prog);
2591 return 0;
2592 }
2593 index--;
2594 }
2595 return -ENOENT;
2596 }
2597
bpf_prog_array_copy(struct bpf_prog_array * old_array,struct bpf_prog * exclude_prog,struct bpf_prog * include_prog,u64 bpf_cookie,struct bpf_prog_array ** new_array)2598 int bpf_prog_array_copy(struct bpf_prog_array *old_array,
2599 struct bpf_prog *exclude_prog,
2600 struct bpf_prog *include_prog,
2601 u64 bpf_cookie,
2602 struct bpf_prog_array **new_array)
2603 {
2604 int new_prog_cnt, carry_prog_cnt = 0;
2605 struct bpf_prog_array_item *existing, *new;
2606 struct bpf_prog_array *array;
2607 bool found_exclude = false;
2608
2609 /* Figure out how many existing progs we need to carry over to
2610 * the new array.
2611 */
2612 if (old_array) {
2613 existing = old_array->items;
2614 for (; existing->prog; existing++) {
2615 if (existing->prog == exclude_prog) {
2616 found_exclude = true;
2617 continue;
2618 }
2619 if (existing->prog != &dummy_bpf_prog.prog)
2620 carry_prog_cnt++;
2621 if (existing->prog == include_prog)
2622 return -EEXIST;
2623 }
2624 }
2625
2626 if (exclude_prog && !found_exclude)
2627 return -ENOENT;
2628
2629 /* How many progs (not NULL) will be in the new array? */
2630 new_prog_cnt = carry_prog_cnt;
2631 if (include_prog)
2632 new_prog_cnt += 1;
2633
2634 /* Do we have any prog (not NULL) in the new array? */
2635 if (!new_prog_cnt) {
2636 *new_array = NULL;
2637 return 0;
2638 }
2639
2640 /* +1 as the end of prog_array is marked with NULL */
2641 array = bpf_prog_array_alloc(new_prog_cnt + 1, GFP_KERNEL);
2642 if (!array)
2643 return -ENOMEM;
2644 new = array->items;
2645
2646 /* Fill in the new prog array */
2647 if (carry_prog_cnt) {
2648 existing = old_array->items;
2649 for (; existing->prog; existing++) {
2650 if (existing->prog == exclude_prog ||
2651 existing->prog == &dummy_bpf_prog.prog)
2652 continue;
2653
2654 new->prog = existing->prog;
2655 new->bpf_cookie = existing->bpf_cookie;
2656 new++;
2657 }
2658 }
2659 if (include_prog) {
2660 new->prog = include_prog;
2661 new->bpf_cookie = bpf_cookie;
2662 new++;
2663 }
2664 new->prog = NULL;
2665 *new_array = array;
2666 return 0;
2667 }
2668
bpf_prog_array_copy_info(struct bpf_prog_array * array,u32 * prog_ids,u32 request_cnt,u32 * prog_cnt)2669 int bpf_prog_array_copy_info(struct bpf_prog_array *array,
2670 u32 *prog_ids, u32 request_cnt,
2671 u32 *prog_cnt)
2672 {
2673 u32 cnt = 0;
2674
2675 if (array)
2676 cnt = bpf_prog_array_length(array);
2677
2678 *prog_cnt = cnt;
2679
2680 /* return early if user requested only program count or nothing to copy */
2681 if (!request_cnt || !cnt)
2682 return 0;
2683
2684 /* this function is called under trace/bpf_trace.c: bpf_event_mutex */
2685 return bpf_prog_array_copy_core(array, prog_ids, request_cnt) ? -ENOSPC
2686 : 0;
2687 }
2688
__bpf_free_used_maps(struct bpf_prog_aux * aux,struct bpf_map ** used_maps,u32 len)2689 void __bpf_free_used_maps(struct bpf_prog_aux *aux,
2690 struct bpf_map **used_maps, u32 len)
2691 {
2692 struct bpf_map *map;
2693 bool sleepable;
2694 u32 i;
2695
2696 sleepable = aux->sleepable;
2697 for (i = 0; i < len; i++) {
2698 map = used_maps[i];
2699 if (map->ops->map_poke_untrack)
2700 map->ops->map_poke_untrack(map, aux);
2701 if (sleepable)
2702 atomic64_dec(&map->sleepable_refcnt);
2703 bpf_map_put(map);
2704 }
2705 }
2706
bpf_free_used_maps(struct bpf_prog_aux * aux)2707 static void bpf_free_used_maps(struct bpf_prog_aux *aux)
2708 {
2709 __bpf_free_used_maps(aux, aux->used_maps, aux->used_map_cnt);
2710 kfree(aux->used_maps);
2711 }
2712
__bpf_free_used_btfs(struct bpf_prog_aux * aux,struct btf_mod_pair * used_btfs,u32 len)2713 void __bpf_free_used_btfs(struct bpf_prog_aux *aux,
2714 struct btf_mod_pair *used_btfs, u32 len)
2715 {
2716 #ifdef CONFIG_BPF_SYSCALL
2717 struct btf_mod_pair *btf_mod;
2718 u32 i;
2719
2720 for (i = 0; i < len; i++) {
2721 btf_mod = &used_btfs[i];
2722 if (btf_mod->module)
2723 module_put(btf_mod->module);
2724 btf_put(btf_mod->btf);
2725 }
2726 #endif
2727 }
2728
bpf_free_used_btfs(struct bpf_prog_aux * aux)2729 static void bpf_free_used_btfs(struct bpf_prog_aux *aux)
2730 {
2731 __bpf_free_used_btfs(aux, aux->used_btfs, aux->used_btf_cnt);
2732 kfree(aux->used_btfs);
2733 }
2734
bpf_prog_free_deferred(struct work_struct * work)2735 static void bpf_prog_free_deferred(struct work_struct *work)
2736 {
2737 struct bpf_prog_aux *aux;
2738 int i;
2739
2740 aux = container_of(work, struct bpf_prog_aux, work);
2741 #ifdef CONFIG_BPF_SYSCALL
2742 bpf_free_kfunc_btf_tab(aux->kfunc_btf_tab);
2743 #endif
2744 #ifdef CONFIG_CGROUP_BPF
2745 if (aux->cgroup_atype != CGROUP_BPF_ATTACH_TYPE_INVALID)
2746 bpf_cgroup_atype_put(aux->cgroup_atype);
2747 #endif
2748 bpf_free_used_maps(aux);
2749 bpf_free_used_btfs(aux);
2750 if (bpf_prog_is_dev_bound(aux))
2751 bpf_prog_dev_bound_destroy(aux->prog);
2752 #ifdef CONFIG_PERF_EVENTS
2753 if (aux->prog->has_callchain_buf)
2754 put_callchain_buffers();
2755 #endif
2756 if (aux->dst_trampoline)
2757 bpf_trampoline_put(aux->dst_trampoline);
2758 for (i = 0; i < aux->func_cnt; i++) {
2759 /* We can just unlink the subprog poke descriptor table as
2760 * it was originally linked to the main program and is also
2761 * released along with it.
2762 */
2763 aux->func[i]->aux->poke_tab = NULL;
2764 bpf_jit_free(aux->func[i]);
2765 }
2766 if (aux->func_cnt) {
2767 kfree(aux->func);
2768 bpf_prog_unlock_free(aux->prog);
2769 } else {
2770 bpf_jit_free(aux->prog);
2771 }
2772 }
2773
bpf_prog_free(struct bpf_prog * fp)2774 void bpf_prog_free(struct bpf_prog *fp)
2775 {
2776 struct bpf_prog_aux *aux = fp->aux;
2777
2778 if (aux->dst_prog)
2779 bpf_prog_put(aux->dst_prog);
2780 INIT_WORK(&aux->work, bpf_prog_free_deferred);
2781 schedule_work(&aux->work);
2782 }
2783 EXPORT_SYMBOL_GPL(bpf_prog_free);
2784
2785 /* RNG for unpriviledged user space with separated state from prandom_u32(). */
2786 static DEFINE_PER_CPU(struct rnd_state, bpf_user_rnd_state);
2787
bpf_user_rnd_init_once(void)2788 void bpf_user_rnd_init_once(void)
2789 {
2790 prandom_init_once(&bpf_user_rnd_state);
2791 }
2792
BPF_CALL_0(bpf_user_rnd_u32)2793 BPF_CALL_0(bpf_user_rnd_u32)
2794 {
2795 /* Should someone ever have the rather unwise idea to use some
2796 * of the registers passed into this function, then note that
2797 * this function is called from native eBPF and classic-to-eBPF
2798 * transformations. Register assignments from both sides are
2799 * different, f.e. classic always sets fn(ctx, A, X) here.
2800 */
2801 struct rnd_state *state;
2802 u32 res;
2803
2804 state = &get_cpu_var(bpf_user_rnd_state);
2805 res = prandom_u32_state(state);
2806 put_cpu_var(bpf_user_rnd_state);
2807
2808 return res;
2809 }
2810
BPF_CALL_0(bpf_get_raw_cpu_id)2811 BPF_CALL_0(bpf_get_raw_cpu_id)
2812 {
2813 return raw_smp_processor_id();
2814 }
2815
2816 /* Weak definitions of helper functions in case we don't have bpf syscall. */
2817 const struct bpf_func_proto bpf_map_lookup_elem_proto __weak;
2818 const struct bpf_func_proto bpf_map_update_elem_proto __weak;
2819 const struct bpf_func_proto bpf_map_delete_elem_proto __weak;
2820 const struct bpf_func_proto bpf_map_push_elem_proto __weak;
2821 const struct bpf_func_proto bpf_map_pop_elem_proto __weak;
2822 const struct bpf_func_proto bpf_map_peek_elem_proto __weak;
2823 const struct bpf_func_proto bpf_map_lookup_percpu_elem_proto __weak;
2824 const struct bpf_func_proto bpf_spin_lock_proto __weak;
2825 const struct bpf_func_proto bpf_spin_unlock_proto __weak;
2826 const struct bpf_func_proto bpf_jiffies64_proto __weak;
2827
2828 const struct bpf_func_proto bpf_get_prandom_u32_proto __weak;
2829 const struct bpf_func_proto bpf_get_smp_processor_id_proto __weak;
2830 const struct bpf_func_proto bpf_get_numa_node_id_proto __weak;
2831 const struct bpf_func_proto bpf_ktime_get_ns_proto __weak;
2832 const struct bpf_func_proto bpf_ktime_get_boot_ns_proto __weak;
2833 const struct bpf_func_proto bpf_ktime_get_coarse_ns_proto __weak;
2834 const struct bpf_func_proto bpf_ktime_get_tai_ns_proto __weak;
2835
2836 const struct bpf_func_proto bpf_get_current_pid_tgid_proto __weak;
2837 const struct bpf_func_proto bpf_get_current_uid_gid_proto __weak;
2838 const struct bpf_func_proto bpf_get_current_comm_proto __weak;
2839 const struct bpf_func_proto bpf_get_current_cgroup_id_proto __weak;
2840 const struct bpf_func_proto bpf_get_current_ancestor_cgroup_id_proto __weak;
2841 const struct bpf_func_proto bpf_get_local_storage_proto __weak;
2842 const struct bpf_func_proto bpf_get_ns_current_pid_tgid_proto __weak;
2843 const struct bpf_func_proto bpf_snprintf_btf_proto __weak;
2844 const struct bpf_func_proto bpf_seq_printf_btf_proto __weak;
2845 const struct bpf_func_proto bpf_set_retval_proto __weak;
2846 const struct bpf_func_proto bpf_get_retval_proto __weak;
2847
bpf_get_trace_printk_proto(void)2848 const struct bpf_func_proto * __weak bpf_get_trace_printk_proto(void)
2849 {
2850 return NULL;
2851 }
2852
bpf_get_trace_vprintk_proto(void)2853 const struct bpf_func_proto * __weak bpf_get_trace_vprintk_proto(void)
2854 {
2855 return NULL;
2856 }
2857
2858 u64 __weak
bpf_event_output(struct bpf_map * map,u64 flags,void * meta,u64 meta_size,void * ctx,u64 ctx_size,bpf_ctx_copy_t ctx_copy)2859 bpf_event_output(struct bpf_map *map, u64 flags, void *meta, u64 meta_size,
2860 void *ctx, u64 ctx_size, bpf_ctx_copy_t ctx_copy)
2861 {
2862 return -ENOTSUPP;
2863 }
2864 EXPORT_SYMBOL_GPL(bpf_event_output);
2865
2866 /* Always built-in helper functions. */
2867 const struct bpf_func_proto bpf_tail_call_proto = {
2868 .func = NULL,
2869 .gpl_only = false,
2870 .ret_type = RET_VOID,
2871 .arg1_type = ARG_PTR_TO_CTX,
2872 .arg2_type = ARG_CONST_MAP_PTR,
2873 .arg3_type = ARG_ANYTHING,
2874 };
2875
2876 /* Stub for JITs that only support cBPF. eBPF programs are interpreted.
2877 * It is encouraged to implement bpf_int_jit_compile() instead, so that
2878 * eBPF and implicitly also cBPF can get JITed!
2879 */
bpf_int_jit_compile(struct bpf_prog * prog)2880 struct bpf_prog * __weak bpf_int_jit_compile(struct bpf_prog *prog)
2881 {
2882 return prog;
2883 }
2884
2885 /* Stub for JITs that support eBPF. All cBPF code gets transformed into
2886 * eBPF by the kernel and is later compiled by bpf_int_jit_compile().
2887 */
bpf_jit_compile(struct bpf_prog * prog)2888 void __weak bpf_jit_compile(struct bpf_prog *prog)
2889 {
2890 }
2891
bpf_helper_changes_pkt_data(void * func)2892 bool __weak bpf_helper_changes_pkt_data(void *func)
2893 {
2894 return false;
2895 }
2896
2897 /* Return TRUE if the JIT backend wants verifier to enable sub-register usage
2898 * analysis code and wants explicit zero extension inserted by verifier.
2899 * Otherwise, return FALSE.
2900 *
2901 * The verifier inserts an explicit zero extension after BPF_CMPXCHGs even if
2902 * you don't override this. JITs that don't want these extra insns can detect
2903 * them using insn_is_zext.
2904 */
bpf_jit_needs_zext(void)2905 bool __weak bpf_jit_needs_zext(void)
2906 {
2907 return false;
2908 }
2909
2910 /* Return TRUE if the JIT backend supports mixing bpf2bpf and tailcalls. */
bpf_jit_supports_subprog_tailcalls(void)2911 bool __weak bpf_jit_supports_subprog_tailcalls(void)
2912 {
2913 return false;
2914 }
2915
bpf_jit_supports_kfunc_call(void)2916 bool __weak bpf_jit_supports_kfunc_call(void)
2917 {
2918 return false;
2919 }
2920
bpf_jit_supports_far_kfunc_call(void)2921 bool __weak bpf_jit_supports_far_kfunc_call(void)
2922 {
2923 return false;
2924 }
2925
2926 /* To execute LD_ABS/LD_IND instructions __bpf_prog_run() may call
2927 * skb_copy_bits(), so provide a weak definition of it for NET-less config.
2928 */
skb_copy_bits(const struct sk_buff * skb,int offset,void * to,int len)2929 int __weak skb_copy_bits(const struct sk_buff *skb, int offset, void *to,
2930 int len)
2931 {
2932 return -EFAULT;
2933 }
2934
bpf_arch_text_poke(void * ip,enum bpf_text_poke_type t,void * addr1,void * addr2)2935 int __weak bpf_arch_text_poke(void *ip, enum bpf_text_poke_type t,
2936 void *addr1, void *addr2)
2937 {
2938 return -ENOTSUPP;
2939 }
2940
bpf_arch_text_copy(void * dst,void * src,size_t len)2941 void * __weak bpf_arch_text_copy(void *dst, void *src, size_t len)
2942 {
2943 return ERR_PTR(-ENOTSUPP);
2944 }
2945
bpf_arch_text_invalidate(void * dst,size_t len)2946 int __weak bpf_arch_text_invalidate(void *dst, size_t len)
2947 {
2948 return -ENOTSUPP;
2949 }
2950
2951 #ifdef CONFIG_BPF_SYSCALL
bpf_global_ma_init(void)2952 static int __init bpf_global_ma_init(void)
2953 {
2954 int ret;
2955
2956 ret = bpf_mem_alloc_init(&bpf_global_ma, 0, false);
2957 bpf_global_ma_set = !ret;
2958 return ret;
2959 }
2960 late_initcall(bpf_global_ma_init);
2961 #endif
2962
2963 DEFINE_STATIC_KEY_FALSE(bpf_stats_enabled_key);
2964 EXPORT_SYMBOL(bpf_stats_enabled_key);
2965
2966 /* All definitions of tracepoints related to BPF. */
2967 #define CREATE_TRACE_POINTS
2968 #include <linux/bpf_trace.h>
2969
2970 EXPORT_TRACEPOINT_SYMBOL_GPL(xdp_exception);
2971 EXPORT_TRACEPOINT_SYMBOL_GPL(xdp_bulk_tx);
2972