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/bpf.h>
26 #include <linux/btf.h>
27 #include <linux/objtool.h>
28 #include <linux/overflow.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 #include <linux/execmem.h>
41
42 #include <asm/barrier.h>
43 #include <asm/unaligned.h>
44
45 /* Registers */
46 #define BPF_R0 regs[BPF_REG_0]
47 #define BPF_R1 regs[BPF_REG_1]
48 #define BPF_R2 regs[BPF_REG_2]
49 #define BPF_R3 regs[BPF_REG_3]
50 #define BPF_R4 regs[BPF_REG_4]
51 #define BPF_R5 regs[BPF_REG_5]
52 #define BPF_R6 regs[BPF_REG_6]
53 #define BPF_R7 regs[BPF_REG_7]
54 #define BPF_R8 regs[BPF_REG_8]
55 #define BPF_R9 regs[BPF_REG_9]
56 #define BPF_R10 regs[BPF_REG_10]
57
58 /* Named registers */
59 #define DST regs[insn->dst_reg]
60 #define SRC regs[insn->src_reg]
61 #define FP regs[BPF_REG_FP]
62 #define AX regs[BPF_REG_AX]
63 #define ARG1 regs[BPF_REG_ARG1]
64 #define CTX regs[BPF_REG_CTX]
65 #define OFF insn->off
66 #define IMM insn->imm
67
68 struct bpf_mem_alloc bpf_global_ma;
69 bool bpf_global_ma_set;
70
71 /* No hurry in this branch
72 *
73 * Exported for the bpf jit load helper.
74 */
bpf_internal_load_pointer_neg_helper(const struct sk_buff * skb,int k,unsigned int size)75 void *bpf_internal_load_pointer_neg_helper(const struct sk_buff *skb, int k, unsigned int size)
76 {
77 u8 *ptr = NULL;
78
79 if (k >= SKF_NET_OFF) {
80 ptr = skb_network_header(skb) + k - SKF_NET_OFF;
81 } else if (k >= SKF_LL_OFF) {
82 if (unlikely(!skb_mac_header_was_set(skb)))
83 return NULL;
84 ptr = skb_mac_header(skb) + k - SKF_LL_OFF;
85 }
86 if (ptr >= skb->head && ptr + size <= skb_tail_pointer(skb))
87 return ptr;
88
89 return NULL;
90 }
91
92 /* tell bpf programs that include vmlinux.h kernel's PAGE_SIZE */
93 enum page_size_enum {
94 __PAGE_SIZE = PAGE_SIZE
95 };
96
bpf_prog_alloc_no_stats(unsigned int size,gfp_t gfp_extra_flags)97 struct bpf_prog *bpf_prog_alloc_no_stats(unsigned int size, gfp_t gfp_extra_flags)
98 {
99 gfp_t gfp_flags = bpf_memcg_flags(GFP_KERNEL | __GFP_ZERO | gfp_extra_flags);
100 struct bpf_prog_aux *aux;
101 struct bpf_prog *fp;
102
103 size = round_up(size, __PAGE_SIZE);
104 fp = __vmalloc(size, gfp_flags);
105 if (fp == NULL)
106 return NULL;
107
108 aux = kzalloc(sizeof(*aux), bpf_memcg_flags(GFP_KERNEL | gfp_extra_flags));
109 if (aux == NULL) {
110 vfree(fp);
111 return NULL;
112 }
113 fp->active = alloc_percpu_gfp(int, bpf_memcg_flags(GFP_KERNEL | gfp_extra_flags));
114 if (!fp->active) {
115 vfree(fp);
116 kfree(aux);
117 return NULL;
118 }
119
120 fp->pages = size / PAGE_SIZE;
121 fp->aux = aux;
122 fp->aux->prog = fp;
123 fp->jit_requested = ebpf_jit_enabled();
124 fp->blinding_requested = bpf_jit_blinding_enabled(fp);
125 #ifdef CONFIG_CGROUP_BPF
126 aux->cgroup_atype = CGROUP_BPF_ATTACH_TYPE_INVALID;
127 #endif
128
129 INIT_LIST_HEAD_RCU(&fp->aux->ksym.lnode);
130 #ifdef CONFIG_FINEIBT
131 INIT_LIST_HEAD_RCU(&fp->aux->ksym_prefix.lnode);
132 #endif
133 mutex_init(&fp->aux->used_maps_mutex);
134 mutex_init(&fp->aux->dst_mutex);
135
136 return fp;
137 }
138
bpf_prog_alloc(unsigned int size,gfp_t gfp_extra_flags)139 struct bpf_prog *bpf_prog_alloc(unsigned int size, gfp_t gfp_extra_flags)
140 {
141 gfp_t gfp_flags = bpf_memcg_flags(GFP_KERNEL | __GFP_ZERO | gfp_extra_flags);
142 struct bpf_prog *prog;
143 int cpu;
144
145 prog = bpf_prog_alloc_no_stats(size, gfp_extra_flags);
146 if (!prog)
147 return NULL;
148
149 prog->stats = alloc_percpu_gfp(struct bpf_prog_stats, gfp_flags);
150 if (!prog->stats) {
151 free_percpu(prog->active);
152 kfree(prog->aux);
153 vfree(prog);
154 return NULL;
155 }
156
157 for_each_possible_cpu(cpu) {
158 struct bpf_prog_stats *pstats;
159
160 pstats = per_cpu_ptr(prog->stats, cpu);
161 u64_stats_init(&pstats->syncp);
162 }
163 return prog;
164 }
165 EXPORT_SYMBOL_GPL(bpf_prog_alloc);
166
bpf_prog_alloc_jited_linfo(struct bpf_prog * prog)167 int bpf_prog_alloc_jited_linfo(struct bpf_prog *prog)
168 {
169 if (!prog->aux->nr_linfo || !prog->jit_requested)
170 return 0;
171
172 prog->aux->jited_linfo = kvcalloc(prog->aux->nr_linfo,
173 sizeof(*prog->aux->jited_linfo),
174 bpf_memcg_flags(GFP_KERNEL | __GFP_NOWARN));
175 if (!prog->aux->jited_linfo)
176 return -ENOMEM;
177
178 return 0;
179 }
180
bpf_prog_jit_attempt_done(struct bpf_prog * prog)181 void bpf_prog_jit_attempt_done(struct bpf_prog *prog)
182 {
183 if (prog->aux->jited_linfo &&
184 (!prog->jited || !prog->aux->jited_linfo[0])) {
185 kvfree(prog->aux->jited_linfo);
186 prog->aux->jited_linfo = NULL;
187 }
188
189 kfree(prog->aux->kfunc_tab);
190 prog->aux->kfunc_tab = NULL;
191 }
192
193 /* The jit engine is responsible to provide an array
194 * for insn_off to the jited_off mapping (insn_to_jit_off).
195 *
196 * The idx to this array is the insn_off. Hence, the insn_off
197 * here is relative to the prog itself instead of the main prog.
198 * This array has one entry for each xlated bpf insn.
199 *
200 * jited_off is the byte off to the end of the jited insn.
201 *
202 * Hence, with
203 * insn_start:
204 * The first bpf insn off of the prog. The insn off
205 * here is relative to the main prog.
206 * e.g. if prog is a subprog, insn_start > 0
207 * linfo_idx:
208 * The prog's idx to prog->aux->linfo and jited_linfo
209 *
210 * jited_linfo[linfo_idx] = prog->bpf_func
211 *
212 * For i > linfo_idx,
213 *
214 * jited_linfo[i] = prog->bpf_func +
215 * insn_to_jit_off[linfo[i].insn_off - insn_start - 1]
216 */
bpf_prog_fill_jited_linfo(struct bpf_prog * prog,const u32 * insn_to_jit_off)217 void bpf_prog_fill_jited_linfo(struct bpf_prog *prog,
218 const u32 *insn_to_jit_off)
219 {
220 u32 linfo_idx, insn_start, insn_end, nr_linfo, i;
221 const struct bpf_line_info *linfo;
222 void **jited_linfo;
223
224 if (!prog->aux->jited_linfo || prog->aux->func_idx > prog->aux->func_cnt)
225 /* Userspace did not provide linfo */
226 return;
227
228 linfo_idx = prog->aux->linfo_idx;
229 linfo = &prog->aux->linfo[linfo_idx];
230 insn_start = linfo[0].insn_off;
231 insn_end = insn_start + prog->len;
232
233 jited_linfo = &prog->aux->jited_linfo[linfo_idx];
234 jited_linfo[0] = prog->bpf_func;
235
236 nr_linfo = prog->aux->nr_linfo - linfo_idx;
237
238 for (i = 1; i < nr_linfo && linfo[i].insn_off < insn_end; i++)
239 /* The verifier ensures that linfo[i].insn_off is
240 * strictly increasing
241 */
242 jited_linfo[i] = prog->bpf_func +
243 insn_to_jit_off[linfo[i].insn_off - insn_start - 1];
244 }
245
bpf_prog_realloc(struct bpf_prog * fp_old,unsigned int size,gfp_t gfp_extra_flags)246 struct bpf_prog *bpf_prog_realloc(struct bpf_prog *fp_old, unsigned int size,
247 gfp_t gfp_extra_flags)
248 {
249 gfp_t gfp_flags = bpf_memcg_flags(GFP_KERNEL | __GFP_ZERO | gfp_extra_flags);
250 struct bpf_prog *fp;
251 u32 pages;
252
253 size = round_up(size, PAGE_SIZE);
254 pages = size / PAGE_SIZE;
255 if (pages <= fp_old->pages)
256 return fp_old;
257
258 fp = __vmalloc(size, gfp_flags);
259 if (fp) {
260 memcpy(fp, fp_old, fp_old->pages * PAGE_SIZE);
261 fp->pages = pages;
262 fp->aux->prog = fp;
263
264 /* We keep fp->aux from fp_old around in the new
265 * reallocated structure.
266 */
267 fp_old->aux = NULL;
268 fp_old->stats = NULL;
269 fp_old->active = NULL;
270 __bpf_prog_free(fp_old);
271 }
272
273 return fp;
274 }
275
__bpf_prog_free(struct bpf_prog * fp)276 void __bpf_prog_free(struct bpf_prog *fp)
277 {
278 if (fp->aux) {
279 mutex_destroy(&fp->aux->used_maps_mutex);
280 mutex_destroy(&fp->aux->dst_mutex);
281 kfree(fp->aux->poke_tab);
282 kfree(fp->aux);
283 }
284 free_percpu(fp->stats);
285 free_percpu(fp->active);
286 vfree(fp);
287 }
288
bpf_prog_calc_tag(struct bpf_prog * fp)289 int bpf_prog_calc_tag(struct bpf_prog *fp)
290 {
291 const u32 bits_offset = SHA1_BLOCK_SIZE - sizeof(__be64);
292 u32 raw_size = bpf_prog_tag_scratch_size(fp);
293 u32 digest[SHA1_DIGEST_WORDS];
294 u32 ws[SHA1_WORKSPACE_WORDS];
295 u32 i, bsize, psize, blocks;
296 struct bpf_insn *dst;
297 bool was_ld_map;
298 u8 *raw, *todo;
299 __be32 *result;
300 __be64 *bits;
301
302 raw = vmalloc(raw_size);
303 if (!raw)
304 return -ENOMEM;
305
306 sha1_init(digest);
307 memset(ws, 0, sizeof(ws));
308
309 /* We need to take out the map fd for the digest calculation
310 * since they are unstable from user space side.
311 */
312 dst = (void *)raw;
313 for (i = 0, was_ld_map = false; i < fp->len; i++) {
314 dst[i] = fp->insnsi[i];
315 if (!was_ld_map &&
316 dst[i].code == (BPF_LD | BPF_IMM | BPF_DW) &&
317 (dst[i].src_reg == BPF_PSEUDO_MAP_FD ||
318 dst[i].src_reg == BPF_PSEUDO_MAP_VALUE)) {
319 was_ld_map = true;
320 dst[i].imm = 0;
321 } else if (was_ld_map &&
322 dst[i].code == 0 &&
323 dst[i].dst_reg == 0 &&
324 dst[i].src_reg == 0 &&
325 dst[i].off == 0) {
326 was_ld_map = false;
327 dst[i].imm = 0;
328 } else {
329 was_ld_map = false;
330 }
331 }
332
333 psize = bpf_prog_insn_size(fp);
334 memset(&raw[psize], 0, raw_size - psize);
335 raw[psize++] = 0x80;
336
337 bsize = round_up(psize, SHA1_BLOCK_SIZE);
338 blocks = bsize / SHA1_BLOCK_SIZE;
339 todo = raw;
340 if (bsize - psize >= sizeof(__be64)) {
341 bits = (__be64 *)(todo + bsize - sizeof(__be64));
342 } else {
343 bits = (__be64 *)(todo + bsize + bits_offset);
344 blocks++;
345 }
346 *bits = cpu_to_be64((psize - 1) << 3);
347
348 while (blocks--) {
349 sha1_transform(digest, todo, ws);
350 todo += SHA1_BLOCK_SIZE;
351 }
352
353 result = (__force __be32 *)digest;
354 for (i = 0; i < SHA1_DIGEST_WORDS; i++)
355 result[i] = cpu_to_be32(digest[i]);
356 memcpy(fp->tag, result, sizeof(fp->tag));
357
358 vfree(raw);
359 return 0;
360 }
361
bpf_adj_delta_to_imm(struct bpf_insn * insn,u32 pos,s32 end_old,s32 end_new,s32 curr,const bool probe_pass)362 static int bpf_adj_delta_to_imm(struct bpf_insn *insn, u32 pos, s32 end_old,
363 s32 end_new, s32 curr, const bool probe_pass)
364 {
365 const s64 imm_min = S32_MIN, imm_max = S32_MAX;
366 s32 delta = end_new - end_old;
367 s64 imm = insn->imm;
368
369 if (curr < pos && curr + imm + 1 >= end_old)
370 imm += delta;
371 else if (curr >= end_new && curr + imm + 1 < end_new)
372 imm -= delta;
373 if (imm < imm_min || imm > imm_max)
374 return -ERANGE;
375 if (!probe_pass)
376 insn->imm = imm;
377 return 0;
378 }
379
bpf_adj_delta_to_off(struct bpf_insn * insn,u32 pos,s32 end_old,s32 end_new,s32 curr,const bool probe_pass)380 static int bpf_adj_delta_to_off(struct bpf_insn *insn, u32 pos, s32 end_old,
381 s32 end_new, s32 curr, const bool probe_pass)
382 {
383 s64 off_min, off_max, off;
384 s32 delta = end_new - end_old;
385
386 if (insn->code == (BPF_JMP32 | BPF_JA)) {
387 off = insn->imm;
388 off_min = S32_MIN;
389 off_max = S32_MAX;
390 } else {
391 off = insn->off;
392 off_min = S16_MIN;
393 off_max = S16_MAX;
394 }
395
396 if (curr < pos && curr + off + 1 >= end_old)
397 off += delta;
398 else if (curr >= end_new && curr + off + 1 < end_new)
399 off -= delta;
400 if (off < off_min || off > off_max)
401 return -ERANGE;
402 if (!probe_pass) {
403 if (insn->code == (BPF_JMP32 | BPF_JA))
404 insn->imm = off;
405 else
406 insn->off = off;
407 }
408 return 0;
409 }
410
bpf_adj_branches(struct bpf_prog * prog,u32 pos,s32 end_old,s32 end_new,const bool probe_pass)411 static int bpf_adj_branches(struct bpf_prog *prog, u32 pos, s32 end_old,
412 s32 end_new, const bool probe_pass)
413 {
414 u32 i, insn_cnt = prog->len + (probe_pass ? end_new - end_old : 0);
415 struct bpf_insn *insn = prog->insnsi;
416 int ret = 0;
417
418 for (i = 0; i < insn_cnt; i++, insn++) {
419 u8 code;
420
421 /* In the probing pass we still operate on the original,
422 * unpatched image in order to check overflows before we
423 * do any other adjustments. Therefore skip the patchlet.
424 */
425 if (probe_pass && i == pos) {
426 i = end_new;
427 insn = prog->insnsi + end_old;
428 }
429 if (bpf_pseudo_func(insn)) {
430 ret = bpf_adj_delta_to_imm(insn, pos, end_old,
431 end_new, i, probe_pass);
432 if (ret)
433 return ret;
434 continue;
435 }
436 code = insn->code;
437 if ((BPF_CLASS(code) != BPF_JMP &&
438 BPF_CLASS(code) != BPF_JMP32) ||
439 BPF_OP(code) == BPF_EXIT)
440 continue;
441 /* Adjust offset of jmps if we cross patch boundaries. */
442 if (BPF_OP(code) == BPF_CALL) {
443 if (insn->src_reg != BPF_PSEUDO_CALL)
444 continue;
445 ret = bpf_adj_delta_to_imm(insn, pos, end_old,
446 end_new, i, probe_pass);
447 } else {
448 ret = bpf_adj_delta_to_off(insn, pos, end_old,
449 end_new, i, probe_pass);
450 }
451 if (ret)
452 break;
453 }
454
455 return ret;
456 }
457
bpf_adj_linfo(struct bpf_prog * prog,u32 off,u32 delta)458 static void bpf_adj_linfo(struct bpf_prog *prog, u32 off, u32 delta)
459 {
460 struct bpf_line_info *linfo;
461 u32 i, nr_linfo;
462
463 nr_linfo = prog->aux->nr_linfo;
464 if (!nr_linfo || !delta)
465 return;
466
467 linfo = prog->aux->linfo;
468
469 for (i = 0; i < nr_linfo; i++)
470 if (off < linfo[i].insn_off)
471 break;
472
473 /* Push all off < linfo[i].insn_off by delta */
474 for (; i < nr_linfo; i++)
475 linfo[i].insn_off += delta;
476 }
477
bpf_patch_insn_single(struct bpf_prog * prog,u32 off,const struct bpf_insn * patch,u32 len)478 struct bpf_prog *bpf_patch_insn_single(struct bpf_prog *prog, u32 off,
479 const struct bpf_insn *patch, u32 len)
480 {
481 u32 insn_adj_cnt, insn_rest, insn_delta = len - 1;
482 const u32 cnt_max = S16_MAX;
483 struct bpf_prog *prog_adj;
484 int err;
485
486 /* Since our patchlet doesn't expand the image, we're done. */
487 if (insn_delta == 0) {
488 memcpy(prog->insnsi + off, patch, sizeof(*patch));
489 return prog;
490 }
491
492 insn_adj_cnt = prog->len + insn_delta;
493
494 /* Reject anything that would potentially let the insn->off
495 * target overflow when we have excessive program expansions.
496 * We need to probe here before we do any reallocation where
497 * we afterwards may not fail anymore.
498 */
499 if (insn_adj_cnt > cnt_max &&
500 (err = bpf_adj_branches(prog, off, off + 1, off + len, true)))
501 return ERR_PTR(err);
502
503 /* Several new instructions need to be inserted. Make room
504 * for them. Likely, there's no need for a new allocation as
505 * last page could have large enough tailroom.
506 */
507 prog_adj = bpf_prog_realloc(prog, bpf_prog_size(insn_adj_cnt),
508 GFP_USER);
509 if (!prog_adj)
510 return ERR_PTR(-ENOMEM);
511
512 prog_adj->len = insn_adj_cnt;
513
514 /* Patching happens in 3 steps:
515 *
516 * 1) Move over tail of insnsi from next instruction onwards,
517 * so we can patch the single target insn with one or more
518 * new ones (patching is always from 1 to n insns, n > 0).
519 * 2) Inject new instructions at the target location.
520 * 3) Adjust branch offsets if necessary.
521 */
522 insn_rest = insn_adj_cnt - off - len;
523
524 memmove(prog_adj->insnsi + off + len, prog_adj->insnsi + off + 1,
525 sizeof(*patch) * insn_rest);
526 memcpy(prog_adj->insnsi + off, patch, sizeof(*patch) * len);
527
528 /* We are guaranteed to not fail at this point, otherwise
529 * the ship has sailed to reverse to the original state. An
530 * overflow cannot happen at this point.
531 */
532 BUG_ON(bpf_adj_branches(prog_adj, off, off + 1, off + len, false));
533
534 bpf_adj_linfo(prog_adj, off, insn_delta);
535
536 return prog_adj;
537 }
538
bpf_remove_insns(struct bpf_prog * prog,u32 off,u32 cnt)539 int bpf_remove_insns(struct bpf_prog *prog, u32 off, u32 cnt)
540 {
541 /* Branch offsets can't overflow when program is shrinking, no need
542 * to call bpf_adj_branches(..., true) here
543 */
544 memmove(prog->insnsi + off, prog->insnsi + off + cnt,
545 sizeof(struct bpf_insn) * (prog->len - off - cnt));
546 prog->len -= cnt;
547
548 return WARN_ON_ONCE(bpf_adj_branches(prog, off, off + cnt, off, false));
549 }
550
bpf_prog_kallsyms_del_subprogs(struct bpf_prog * fp)551 static void bpf_prog_kallsyms_del_subprogs(struct bpf_prog *fp)
552 {
553 int i;
554
555 for (i = 0; i < fp->aux->real_func_cnt; i++)
556 bpf_prog_kallsyms_del(fp->aux->func[i]);
557 }
558
bpf_prog_kallsyms_del_all(struct bpf_prog * fp)559 void bpf_prog_kallsyms_del_all(struct bpf_prog *fp)
560 {
561 bpf_prog_kallsyms_del_subprogs(fp);
562 bpf_prog_kallsyms_del(fp);
563 }
564
565 #ifdef CONFIG_BPF_JIT
566 /* All BPF JIT sysctl knobs here. */
567 int bpf_jit_enable __read_mostly = IS_BUILTIN(CONFIG_BPF_JIT_DEFAULT_ON);
568 int bpf_jit_kallsyms __read_mostly = IS_BUILTIN(CONFIG_BPF_JIT_DEFAULT_ON);
569 int bpf_jit_harden __read_mostly;
570 long bpf_jit_limit __read_mostly;
571 long bpf_jit_limit_max __read_mostly;
572
573 static void
bpf_prog_ksym_set_addr(struct bpf_prog * prog)574 bpf_prog_ksym_set_addr(struct bpf_prog *prog)
575 {
576 WARN_ON_ONCE(!bpf_prog_ebpf_jited(prog));
577
578 prog->aux->ksym.start = (unsigned long) prog->bpf_func;
579 prog->aux->ksym.end = prog->aux->ksym.start + prog->jited_len;
580 }
581
582 static void
bpf_prog_ksym_set_name(struct bpf_prog * prog)583 bpf_prog_ksym_set_name(struct bpf_prog *prog)
584 {
585 char *sym = prog->aux->ksym.name;
586 const char *end = sym + KSYM_NAME_LEN;
587 const struct btf_type *type;
588 const char *func_name;
589
590 BUILD_BUG_ON(sizeof("bpf_prog_") +
591 sizeof(prog->tag) * 2 +
592 /* name has been null terminated.
593 * We should need +1 for the '_' preceding
594 * the name. However, the null character
595 * is double counted between the name and the
596 * sizeof("bpf_prog_") above, so we omit
597 * the +1 here.
598 */
599 sizeof(prog->aux->name) > KSYM_NAME_LEN);
600
601 sym += snprintf(sym, KSYM_NAME_LEN, "bpf_prog_");
602 sym = bin2hex(sym, prog->tag, sizeof(prog->tag));
603
604 /* prog->aux->name will be ignored if full btf name is available */
605 if (prog->aux->func_info_cnt && prog->aux->func_idx < prog->aux->func_info_cnt) {
606 type = btf_type_by_id(prog->aux->btf,
607 prog->aux->func_info[prog->aux->func_idx].type_id);
608 func_name = btf_name_by_offset(prog->aux->btf, type->name_off);
609 snprintf(sym, (size_t)(end - sym), "_%s", func_name);
610 return;
611 }
612
613 if (prog->aux->name[0])
614 snprintf(sym, (size_t)(end - sym), "_%s", prog->aux->name);
615 else
616 *sym = 0;
617 }
618
bpf_get_ksym_start(struct latch_tree_node * n)619 static unsigned long bpf_get_ksym_start(struct latch_tree_node *n)
620 {
621 return container_of(n, struct bpf_ksym, tnode)->start;
622 }
623
bpf_tree_less(struct latch_tree_node * a,struct latch_tree_node * b)624 static __always_inline bool bpf_tree_less(struct latch_tree_node *a,
625 struct latch_tree_node *b)
626 {
627 return bpf_get_ksym_start(a) < bpf_get_ksym_start(b);
628 }
629
bpf_tree_comp(void * key,struct latch_tree_node * n)630 static __always_inline int bpf_tree_comp(void *key, struct latch_tree_node *n)
631 {
632 unsigned long val = (unsigned long)key;
633 const struct bpf_ksym *ksym;
634
635 ksym = container_of(n, struct bpf_ksym, tnode);
636
637 if (val < ksym->start)
638 return -1;
639 /* Ensure that we detect return addresses as part of the program, when
640 * the final instruction is a call for a program part of the stack
641 * trace. Therefore, do val > ksym->end instead of val >= ksym->end.
642 */
643 if (val > ksym->end)
644 return 1;
645
646 return 0;
647 }
648
649 static const struct latch_tree_ops bpf_tree_ops = {
650 .less = bpf_tree_less,
651 .comp = bpf_tree_comp,
652 };
653
654 static DEFINE_SPINLOCK(bpf_lock);
655 static LIST_HEAD(bpf_kallsyms);
656 static struct latch_tree_root bpf_tree __cacheline_aligned;
657
bpf_ksym_add(struct bpf_ksym * ksym)658 void bpf_ksym_add(struct bpf_ksym *ksym)
659 {
660 spin_lock_bh(&bpf_lock);
661 WARN_ON_ONCE(!list_empty(&ksym->lnode));
662 list_add_tail_rcu(&ksym->lnode, &bpf_kallsyms);
663 latch_tree_insert(&ksym->tnode, &bpf_tree, &bpf_tree_ops);
664 spin_unlock_bh(&bpf_lock);
665 }
666
__bpf_ksym_del(struct bpf_ksym * ksym)667 static void __bpf_ksym_del(struct bpf_ksym *ksym)
668 {
669 if (list_empty(&ksym->lnode))
670 return;
671
672 latch_tree_erase(&ksym->tnode, &bpf_tree, &bpf_tree_ops);
673 list_del_rcu(&ksym->lnode);
674 }
675
bpf_ksym_del(struct bpf_ksym * ksym)676 void bpf_ksym_del(struct bpf_ksym *ksym)
677 {
678 spin_lock_bh(&bpf_lock);
679 __bpf_ksym_del(ksym);
680 spin_unlock_bh(&bpf_lock);
681 }
682
bpf_prog_kallsyms_candidate(const struct bpf_prog * fp)683 static bool bpf_prog_kallsyms_candidate(const struct bpf_prog *fp)
684 {
685 return fp->jited && !bpf_prog_was_classic(fp);
686 }
687
bpf_prog_kallsyms_add(struct bpf_prog * fp)688 void bpf_prog_kallsyms_add(struct bpf_prog *fp)
689 {
690 if (!bpf_prog_kallsyms_candidate(fp) ||
691 !bpf_token_capable(fp->aux->token, CAP_BPF))
692 return;
693
694 bpf_prog_ksym_set_addr(fp);
695 bpf_prog_ksym_set_name(fp);
696 fp->aux->ksym.prog = true;
697
698 bpf_ksym_add(&fp->aux->ksym);
699
700 #ifdef CONFIG_FINEIBT
701 /*
702 * When FineIBT, code in the __cfi_foo() symbols can get executed
703 * and hence unwinder needs help.
704 */
705 if (cfi_mode != CFI_FINEIBT)
706 return;
707
708 snprintf(fp->aux->ksym_prefix.name, KSYM_NAME_LEN,
709 "__cfi_%s", fp->aux->ksym.name);
710
711 fp->aux->ksym_prefix.start = (unsigned long) fp->bpf_func - 16;
712 fp->aux->ksym_prefix.end = (unsigned long) fp->bpf_func;
713
714 bpf_ksym_add(&fp->aux->ksym_prefix);
715 #endif
716 }
717
bpf_prog_kallsyms_del(struct bpf_prog * fp)718 void bpf_prog_kallsyms_del(struct bpf_prog *fp)
719 {
720 if (!bpf_prog_kallsyms_candidate(fp))
721 return;
722
723 bpf_ksym_del(&fp->aux->ksym);
724 #ifdef CONFIG_FINEIBT
725 if (cfi_mode != CFI_FINEIBT)
726 return;
727 bpf_ksym_del(&fp->aux->ksym_prefix);
728 #endif
729 }
730
bpf_ksym_find(unsigned long addr)731 static struct bpf_ksym *bpf_ksym_find(unsigned long addr)
732 {
733 struct latch_tree_node *n;
734
735 n = latch_tree_find((void *)addr, &bpf_tree, &bpf_tree_ops);
736 return n ? container_of(n, struct bpf_ksym, tnode) : NULL;
737 }
738
__bpf_address_lookup(unsigned long addr,unsigned long * size,unsigned long * off,char * sym)739 const char *__bpf_address_lookup(unsigned long addr, unsigned long *size,
740 unsigned long *off, char *sym)
741 {
742 struct bpf_ksym *ksym;
743 char *ret = NULL;
744
745 rcu_read_lock();
746 ksym = bpf_ksym_find(addr);
747 if (ksym) {
748 unsigned long symbol_start = ksym->start;
749 unsigned long symbol_end = ksym->end;
750
751 strscpy(sym, ksym->name, KSYM_NAME_LEN);
752
753 ret = sym;
754 if (size)
755 *size = symbol_end - symbol_start;
756 if (off)
757 *off = addr - symbol_start;
758 }
759 rcu_read_unlock();
760
761 return ret;
762 }
763
is_bpf_text_address(unsigned long addr)764 bool is_bpf_text_address(unsigned long addr)
765 {
766 bool ret;
767
768 rcu_read_lock();
769 ret = bpf_ksym_find(addr) != NULL;
770 rcu_read_unlock();
771
772 return ret;
773 }
774
bpf_prog_ksym_find(unsigned long addr)775 struct bpf_prog *bpf_prog_ksym_find(unsigned long addr)
776 {
777 struct bpf_ksym *ksym = bpf_ksym_find(addr);
778
779 return ksym && ksym->prog ?
780 container_of(ksym, struct bpf_prog_aux, ksym)->prog :
781 NULL;
782 }
783
search_bpf_extables(unsigned long addr)784 const struct exception_table_entry *search_bpf_extables(unsigned long addr)
785 {
786 const struct exception_table_entry *e = NULL;
787 struct bpf_prog *prog;
788
789 rcu_read_lock();
790 prog = bpf_prog_ksym_find(addr);
791 if (!prog)
792 goto out;
793 if (!prog->aux->num_exentries)
794 goto out;
795
796 e = search_extable(prog->aux->extable, prog->aux->num_exentries, addr);
797 out:
798 rcu_read_unlock();
799 return e;
800 }
801
bpf_get_kallsym(unsigned int symnum,unsigned long * value,char * type,char * sym)802 int bpf_get_kallsym(unsigned int symnum, unsigned long *value, char *type,
803 char *sym)
804 {
805 struct bpf_ksym *ksym;
806 unsigned int it = 0;
807 int ret = -ERANGE;
808
809 if (!bpf_jit_kallsyms_enabled())
810 return ret;
811
812 rcu_read_lock();
813 list_for_each_entry_rcu(ksym, &bpf_kallsyms, lnode) {
814 if (it++ != symnum)
815 continue;
816
817 strscpy(sym, ksym->name, KSYM_NAME_LEN);
818
819 *value = ksym->start;
820 *type = BPF_SYM_ELF_TYPE;
821
822 ret = 0;
823 break;
824 }
825 rcu_read_unlock();
826
827 return ret;
828 }
829
bpf_jit_add_poke_descriptor(struct bpf_prog * prog,struct bpf_jit_poke_descriptor * poke)830 int bpf_jit_add_poke_descriptor(struct bpf_prog *prog,
831 struct bpf_jit_poke_descriptor *poke)
832 {
833 struct bpf_jit_poke_descriptor *tab = prog->aux->poke_tab;
834 static const u32 poke_tab_max = 1024;
835 u32 slot = prog->aux->size_poke_tab;
836 u32 size = slot + 1;
837
838 if (size > poke_tab_max)
839 return -ENOSPC;
840 if (poke->tailcall_target || poke->tailcall_target_stable ||
841 poke->tailcall_bypass || poke->adj_off || poke->bypass_addr)
842 return -EINVAL;
843
844 switch (poke->reason) {
845 case BPF_POKE_REASON_TAIL_CALL:
846 if (!poke->tail_call.map)
847 return -EINVAL;
848 break;
849 default:
850 return -EINVAL;
851 }
852
853 tab = krealloc_array(tab, size, sizeof(*poke), GFP_KERNEL);
854 if (!tab)
855 return -ENOMEM;
856
857 memcpy(&tab[slot], poke, sizeof(*poke));
858 prog->aux->size_poke_tab = size;
859 prog->aux->poke_tab = tab;
860
861 return slot;
862 }
863
864 /*
865 * BPF program pack allocator.
866 *
867 * Most BPF programs are pretty small. Allocating a hole page for each
868 * program is sometime a waste. Many small bpf program also adds pressure
869 * to instruction TLB. To solve this issue, we introduce a BPF program pack
870 * allocator. The prog_pack allocator uses HPAGE_PMD_SIZE page (2MB on x86)
871 * to host BPF programs.
872 */
873 #define BPF_PROG_CHUNK_SHIFT 6
874 #define BPF_PROG_CHUNK_SIZE (1 << BPF_PROG_CHUNK_SHIFT)
875 #define BPF_PROG_CHUNK_MASK (~(BPF_PROG_CHUNK_SIZE - 1))
876
877 struct bpf_prog_pack {
878 struct list_head list;
879 void *ptr;
880 unsigned long bitmap[];
881 };
882
bpf_jit_fill_hole_with_zero(void * area,unsigned int size)883 void bpf_jit_fill_hole_with_zero(void *area, unsigned int size)
884 {
885 memset(area, 0, size);
886 }
887
888 #define BPF_PROG_SIZE_TO_NBITS(size) (round_up(size, BPF_PROG_CHUNK_SIZE) / BPF_PROG_CHUNK_SIZE)
889
890 static DEFINE_MUTEX(pack_mutex);
891 static LIST_HEAD(pack_list);
892
893 /* PMD_SIZE is not available in some special config, e.g. ARCH=arm with
894 * CONFIG_MMU=n. Use PAGE_SIZE in these cases.
895 */
896 #ifdef PMD_SIZE
897 /* PMD_SIZE is really big for some archs. It doesn't make sense to
898 * reserve too much memory in one allocation. Hardcode BPF_PROG_PACK_SIZE to
899 * 2MiB * num_possible_nodes(). On most architectures PMD_SIZE will be
900 * greater than or equal to 2MB.
901 */
902 #define BPF_PROG_PACK_SIZE (SZ_2M * num_possible_nodes())
903 #else
904 #define BPF_PROG_PACK_SIZE PAGE_SIZE
905 #endif
906
907 #define BPF_PROG_CHUNK_COUNT (BPF_PROG_PACK_SIZE / BPF_PROG_CHUNK_SIZE)
908
alloc_new_pack(bpf_jit_fill_hole_t bpf_fill_ill_insns)909 static struct bpf_prog_pack *alloc_new_pack(bpf_jit_fill_hole_t bpf_fill_ill_insns)
910 {
911 struct bpf_prog_pack *pack;
912 int err;
913
914 pack = kzalloc(struct_size(pack, bitmap, BITS_TO_LONGS(BPF_PROG_CHUNK_COUNT)),
915 GFP_KERNEL);
916 if (!pack)
917 return NULL;
918 pack->ptr = bpf_jit_alloc_exec(BPF_PROG_PACK_SIZE);
919 if (!pack->ptr)
920 goto out;
921 bpf_fill_ill_insns(pack->ptr, BPF_PROG_PACK_SIZE);
922 bitmap_zero(pack->bitmap, BPF_PROG_PACK_SIZE / BPF_PROG_CHUNK_SIZE);
923
924 set_vm_flush_reset_perms(pack->ptr);
925 err = set_memory_rox((unsigned long)pack->ptr,
926 BPF_PROG_PACK_SIZE / PAGE_SIZE);
927 if (err)
928 goto out;
929 list_add_tail(&pack->list, &pack_list);
930 return pack;
931
932 out:
933 bpf_jit_free_exec(pack->ptr);
934 kfree(pack);
935 return NULL;
936 }
937
bpf_prog_pack_alloc(u32 size,bpf_jit_fill_hole_t bpf_fill_ill_insns)938 void *bpf_prog_pack_alloc(u32 size, bpf_jit_fill_hole_t bpf_fill_ill_insns)
939 {
940 unsigned int nbits = BPF_PROG_SIZE_TO_NBITS(size);
941 struct bpf_prog_pack *pack;
942 unsigned long pos;
943 void *ptr = NULL;
944
945 mutex_lock(&pack_mutex);
946 if (size > BPF_PROG_PACK_SIZE) {
947 size = round_up(size, PAGE_SIZE);
948 ptr = bpf_jit_alloc_exec(size);
949 if (ptr) {
950 int err;
951
952 bpf_fill_ill_insns(ptr, size);
953 set_vm_flush_reset_perms(ptr);
954 err = set_memory_rox((unsigned long)ptr,
955 size / PAGE_SIZE);
956 if (err) {
957 bpf_jit_free_exec(ptr);
958 ptr = NULL;
959 }
960 }
961 goto out;
962 }
963 list_for_each_entry(pack, &pack_list, list) {
964 pos = bitmap_find_next_zero_area(pack->bitmap, BPF_PROG_CHUNK_COUNT, 0,
965 nbits, 0);
966 if (pos < BPF_PROG_CHUNK_COUNT)
967 goto found_free_area;
968 }
969
970 pack = alloc_new_pack(bpf_fill_ill_insns);
971 if (!pack)
972 goto out;
973
974 pos = 0;
975
976 found_free_area:
977 bitmap_set(pack->bitmap, pos, nbits);
978 ptr = (void *)(pack->ptr) + (pos << BPF_PROG_CHUNK_SHIFT);
979
980 out:
981 mutex_unlock(&pack_mutex);
982 return ptr;
983 }
984
bpf_prog_pack_free(void * ptr,u32 size)985 void bpf_prog_pack_free(void *ptr, u32 size)
986 {
987 struct bpf_prog_pack *pack = NULL, *tmp;
988 unsigned int nbits;
989 unsigned long pos;
990
991 mutex_lock(&pack_mutex);
992 if (size > BPF_PROG_PACK_SIZE) {
993 bpf_jit_free_exec(ptr);
994 goto out;
995 }
996
997 list_for_each_entry(tmp, &pack_list, list) {
998 if (ptr >= tmp->ptr && (tmp->ptr + BPF_PROG_PACK_SIZE) > ptr) {
999 pack = tmp;
1000 break;
1001 }
1002 }
1003
1004 if (WARN_ONCE(!pack, "bpf_prog_pack bug\n"))
1005 goto out;
1006
1007 nbits = BPF_PROG_SIZE_TO_NBITS(size);
1008 pos = ((unsigned long)ptr - (unsigned long)pack->ptr) >> BPF_PROG_CHUNK_SHIFT;
1009
1010 WARN_ONCE(bpf_arch_text_invalidate(ptr, size),
1011 "bpf_prog_pack bug: missing bpf_arch_text_invalidate?\n");
1012
1013 bitmap_clear(pack->bitmap, pos, nbits);
1014 if (bitmap_find_next_zero_area(pack->bitmap, BPF_PROG_CHUNK_COUNT, 0,
1015 BPF_PROG_CHUNK_COUNT, 0) == 0) {
1016 list_del(&pack->list);
1017 bpf_jit_free_exec(pack->ptr);
1018 kfree(pack);
1019 }
1020 out:
1021 mutex_unlock(&pack_mutex);
1022 }
1023
1024 static atomic_long_t bpf_jit_current;
1025
1026 /* Can be overridden by an arch's JIT compiler if it has a custom,
1027 * dedicated BPF backend memory area, or if neither of the two
1028 * below apply.
1029 */
bpf_jit_alloc_exec_limit(void)1030 u64 __weak bpf_jit_alloc_exec_limit(void)
1031 {
1032 #if defined(MODULES_VADDR)
1033 return MODULES_END - MODULES_VADDR;
1034 #else
1035 return VMALLOC_END - VMALLOC_START;
1036 #endif
1037 }
1038
bpf_jit_charge_init(void)1039 static int __init bpf_jit_charge_init(void)
1040 {
1041 /* Only used as heuristic here to derive limit. */
1042 bpf_jit_limit_max = bpf_jit_alloc_exec_limit();
1043 bpf_jit_limit = min_t(u64, round_up(bpf_jit_limit_max >> 1,
1044 PAGE_SIZE), LONG_MAX);
1045 return 0;
1046 }
1047 pure_initcall(bpf_jit_charge_init);
1048
bpf_jit_charge_modmem(u32 size)1049 int bpf_jit_charge_modmem(u32 size)
1050 {
1051 if (atomic_long_add_return(size, &bpf_jit_current) > READ_ONCE(bpf_jit_limit)) {
1052 if (!bpf_capable()) {
1053 atomic_long_sub(size, &bpf_jit_current);
1054 return -EPERM;
1055 }
1056 }
1057
1058 return 0;
1059 }
1060
bpf_jit_uncharge_modmem(u32 size)1061 void bpf_jit_uncharge_modmem(u32 size)
1062 {
1063 atomic_long_sub(size, &bpf_jit_current);
1064 }
1065
bpf_jit_alloc_exec(unsigned long size)1066 void *__weak bpf_jit_alloc_exec(unsigned long size)
1067 {
1068 return execmem_alloc(EXECMEM_BPF, size);
1069 }
1070
bpf_jit_free_exec(void * addr)1071 void __weak bpf_jit_free_exec(void *addr)
1072 {
1073 execmem_free(addr);
1074 }
1075
1076 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)1077 bpf_jit_binary_alloc(unsigned int proglen, u8 **image_ptr,
1078 unsigned int alignment,
1079 bpf_jit_fill_hole_t bpf_fill_ill_insns)
1080 {
1081 struct bpf_binary_header *hdr;
1082 u32 size, hole, start;
1083
1084 WARN_ON_ONCE(!is_power_of_2(alignment) ||
1085 alignment > BPF_IMAGE_ALIGNMENT);
1086
1087 /* Most of BPF filters are really small, but if some of them
1088 * fill a page, allow at least 128 extra bytes to insert a
1089 * random section of illegal instructions.
1090 */
1091 size = round_up(proglen + sizeof(*hdr) + 128, PAGE_SIZE);
1092
1093 if (bpf_jit_charge_modmem(size))
1094 return NULL;
1095 hdr = bpf_jit_alloc_exec(size);
1096 if (!hdr) {
1097 bpf_jit_uncharge_modmem(size);
1098 return NULL;
1099 }
1100
1101 /* Fill space with illegal/arch-dep instructions. */
1102 bpf_fill_ill_insns(hdr, size);
1103
1104 hdr->size = size;
1105 hole = min_t(unsigned int, size - (proglen + sizeof(*hdr)),
1106 PAGE_SIZE - sizeof(*hdr));
1107 start = get_random_u32_below(hole) & ~(alignment - 1);
1108
1109 /* Leave a random number of instructions before BPF code. */
1110 *image_ptr = &hdr->image[start];
1111
1112 return hdr;
1113 }
1114
bpf_jit_binary_free(struct bpf_binary_header * hdr)1115 void bpf_jit_binary_free(struct bpf_binary_header *hdr)
1116 {
1117 u32 size = hdr->size;
1118
1119 bpf_jit_free_exec(hdr);
1120 bpf_jit_uncharge_modmem(size);
1121 }
1122
1123 /* Allocate jit binary from bpf_prog_pack allocator.
1124 * Since the allocated memory is RO+X, the JIT engine cannot write directly
1125 * to the memory. To solve this problem, a RW buffer is also allocated at
1126 * as the same time. The JIT engine should calculate offsets based on the
1127 * RO memory address, but write JITed program to the RW buffer. Once the
1128 * JIT engine finishes, it calls bpf_jit_binary_pack_finalize, which copies
1129 * the JITed program to the RO memory.
1130 */
1131 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)1132 bpf_jit_binary_pack_alloc(unsigned int proglen, u8 **image_ptr,
1133 unsigned int alignment,
1134 struct bpf_binary_header **rw_header,
1135 u8 **rw_image,
1136 bpf_jit_fill_hole_t bpf_fill_ill_insns)
1137 {
1138 struct bpf_binary_header *ro_header;
1139 u32 size, hole, start;
1140
1141 WARN_ON_ONCE(!is_power_of_2(alignment) ||
1142 alignment > BPF_IMAGE_ALIGNMENT);
1143
1144 /* add 16 bytes for a random section of illegal instructions */
1145 size = round_up(proglen + sizeof(*ro_header) + 16, BPF_PROG_CHUNK_SIZE);
1146
1147 if (bpf_jit_charge_modmem(size))
1148 return NULL;
1149 ro_header = bpf_prog_pack_alloc(size, bpf_fill_ill_insns);
1150 if (!ro_header) {
1151 bpf_jit_uncharge_modmem(size);
1152 return NULL;
1153 }
1154
1155 *rw_header = kvmalloc(size, GFP_KERNEL);
1156 if (!*rw_header) {
1157 bpf_prog_pack_free(ro_header, size);
1158 bpf_jit_uncharge_modmem(size);
1159 return NULL;
1160 }
1161
1162 /* Fill space with illegal/arch-dep instructions. */
1163 bpf_fill_ill_insns(*rw_header, size);
1164 (*rw_header)->size = size;
1165
1166 hole = min_t(unsigned int, size - (proglen + sizeof(*ro_header)),
1167 BPF_PROG_CHUNK_SIZE - sizeof(*ro_header));
1168 start = get_random_u32_below(hole) & ~(alignment - 1);
1169
1170 *image_ptr = &ro_header->image[start];
1171 *rw_image = &(*rw_header)->image[start];
1172
1173 return ro_header;
1174 }
1175
1176 /* 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)1177 int bpf_jit_binary_pack_finalize(struct bpf_prog *prog,
1178 struct bpf_binary_header *ro_header,
1179 struct bpf_binary_header *rw_header)
1180 {
1181 void *ptr;
1182
1183 ptr = bpf_arch_text_copy(ro_header, rw_header, rw_header->size);
1184
1185 kvfree(rw_header);
1186
1187 if (IS_ERR(ptr)) {
1188 bpf_prog_pack_free(ro_header, ro_header->size);
1189 return PTR_ERR(ptr);
1190 }
1191 return 0;
1192 }
1193
1194 /* bpf_jit_binary_pack_free is called in two different scenarios:
1195 * 1) when the program is freed after;
1196 * 2) when the JIT engine fails (before bpf_jit_binary_pack_finalize).
1197 * For case 2), we need to free both the RO memory and the RW buffer.
1198 *
1199 * bpf_jit_binary_pack_free requires proper ro_header->size. However,
1200 * bpf_jit_binary_pack_alloc does not set it. Therefore, ro_header->size
1201 * must be set with either bpf_jit_binary_pack_finalize (normal path) or
1202 * bpf_arch_text_copy (when jit fails).
1203 */
bpf_jit_binary_pack_free(struct bpf_binary_header * ro_header,struct bpf_binary_header * rw_header)1204 void bpf_jit_binary_pack_free(struct bpf_binary_header *ro_header,
1205 struct bpf_binary_header *rw_header)
1206 {
1207 u32 size = ro_header->size;
1208
1209 bpf_prog_pack_free(ro_header, size);
1210 kvfree(rw_header);
1211 bpf_jit_uncharge_modmem(size);
1212 }
1213
1214 struct bpf_binary_header *
bpf_jit_binary_pack_hdr(const struct bpf_prog * fp)1215 bpf_jit_binary_pack_hdr(const struct bpf_prog *fp)
1216 {
1217 unsigned long real_start = (unsigned long)fp->bpf_func;
1218 unsigned long addr;
1219
1220 addr = real_start & BPF_PROG_CHUNK_MASK;
1221 return (void *)addr;
1222 }
1223
1224 static inline struct bpf_binary_header *
bpf_jit_binary_hdr(const struct bpf_prog * fp)1225 bpf_jit_binary_hdr(const struct bpf_prog *fp)
1226 {
1227 unsigned long real_start = (unsigned long)fp->bpf_func;
1228 unsigned long addr;
1229
1230 addr = real_start & PAGE_MASK;
1231 return (void *)addr;
1232 }
1233
1234 /* This symbol is only overridden by archs that have different
1235 * requirements than the usual eBPF JITs, f.e. when they only
1236 * implement cBPF JIT, do not set images read-only, etc.
1237 */
bpf_jit_free(struct bpf_prog * fp)1238 void __weak bpf_jit_free(struct bpf_prog *fp)
1239 {
1240 if (fp->jited) {
1241 struct bpf_binary_header *hdr = bpf_jit_binary_hdr(fp);
1242
1243 bpf_jit_binary_free(hdr);
1244 WARN_ON_ONCE(!bpf_prog_kallsyms_verify_off(fp));
1245 }
1246
1247 bpf_prog_unlock_free(fp);
1248 }
1249
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)1250 int bpf_jit_get_func_addr(const struct bpf_prog *prog,
1251 const struct bpf_insn *insn, bool extra_pass,
1252 u64 *func_addr, bool *func_addr_fixed)
1253 {
1254 s16 off = insn->off;
1255 s32 imm = insn->imm;
1256 u8 *addr;
1257 int err;
1258
1259 *func_addr_fixed = insn->src_reg != BPF_PSEUDO_CALL;
1260 if (!*func_addr_fixed) {
1261 /* Place-holder address till the last pass has collected
1262 * all addresses for JITed subprograms in which case we
1263 * can pick them up from prog->aux.
1264 */
1265 if (!extra_pass)
1266 addr = NULL;
1267 else if (prog->aux->func &&
1268 off >= 0 && off < prog->aux->real_func_cnt)
1269 addr = (u8 *)prog->aux->func[off]->bpf_func;
1270 else
1271 return -EINVAL;
1272 } else if (insn->src_reg == BPF_PSEUDO_KFUNC_CALL &&
1273 bpf_jit_supports_far_kfunc_call()) {
1274 err = bpf_get_kfunc_addr(prog, insn->imm, insn->off, &addr);
1275 if (err)
1276 return err;
1277 } else {
1278 /* Address of a BPF helper call. Since part of the core
1279 * kernel, it's always at a fixed location. __bpf_call_base
1280 * and the helper with imm relative to it are both in core
1281 * kernel.
1282 */
1283 addr = (u8 *)__bpf_call_base + imm;
1284 }
1285
1286 *func_addr = (unsigned long)addr;
1287 return 0;
1288 }
1289
bpf_jit_blind_insn(const struct bpf_insn * from,const struct bpf_insn * aux,struct bpf_insn * to_buff,bool emit_zext)1290 static int bpf_jit_blind_insn(const struct bpf_insn *from,
1291 const struct bpf_insn *aux,
1292 struct bpf_insn *to_buff,
1293 bool emit_zext)
1294 {
1295 struct bpf_insn *to = to_buff;
1296 u32 imm_rnd = get_random_u32();
1297 s16 off;
1298
1299 BUILD_BUG_ON(BPF_REG_AX + 1 != MAX_BPF_JIT_REG);
1300 BUILD_BUG_ON(MAX_BPF_REG + 1 != MAX_BPF_JIT_REG);
1301
1302 /* Constraints on AX register:
1303 *
1304 * AX register is inaccessible from user space. It is mapped in
1305 * all JITs, and used here for constant blinding rewrites. It is
1306 * typically "stateless" meaning its contents are only valid within
1307 * the executed instruction, but not across several instructions.
1308 * There are a few exceptions however which are further detailed
1309 * below.
1310 *
1311 * Constant blinding is only used by JITs, not in the interpreter.
1312 * The interpreter uses AX in some occasions as a local temporary
1313 * register e.g. in DIV or MOD instructions.
1314 *
1315 * In restricted circumstances, the verifier can also use the AX
1316 * register for rewrites as long as they do not interfere with
1317 * the above cases!
1318 */
1319 if (from->dst_reg == BPF_REG_AX || from->src_reg == BPF_REG_AX)
1320 goto out;
1321
1322 if (from->imm == 0 &&
1323 (from->code == (BPF_ALU | BPF_MOV | BPF_K) ||
1324 from->code == (BPF_ALU64 | BPF_MOV | BPF_K))) {
1325 *to++ = BPF_ALU64_REG(BPF_XOR, from->dst_reg, from->dst_reg);
1326 goto out;
1327 }
1328
1329 switch (from->code) {
1330 case BPF_ALU | BPF_ADD | BPF_K:
1331 case BPF_ALU | BPF_SUB | BPF_K:
1332 case BPF_ALU | BPF_AND | BPF_K:
1333 case BPF_ALU | BPF_OR | BPF_K:
1334 case BPF_ALU | BPF_XOR | BPF_K:
1335 case BPF_ALU | BPF_MUL | BPF_K:
1336 case BPF_ALU | BPF_MOV | BPF_K:
1337 case BPF_ALU | BPF_DIV | BPF_K:
1338 case BPF_ALU | BPF_MOD | BPF_K:
1339 *to++ = BPF_ALU32_IMM(BPF_MOV, BPF_REG_AX, imm_rnd ^ from->imm);
1340 *to++ = BPF_ALU32_IMM(BPF_XOR, BPF_REG_AX, imm_rnd);
1341 *to++ = BPF_ALU32_REG_OFF(from->code, from->dst_reg, BPF_REG_AX, from->off);
1342 break;
1343
1344 case BPF_ALU64 | BPF_ADD | BPF_K:
1345 case BPF_ALU64 | BPF_SUB | BPF_K:
1346 case BPF_ALU64 | BPF_AND | BPF_K:
1347 case BPF_ALU64 | BPF_OR | BPF_K:
1348 case BPF_ALU64 | BPF_XOR | BPF_K:
1349 case BPF_ALU64 | BPF_MUL | BPF_K:
1350 case BPF_ALU64 | BPF_MOV | BPF_K:
1351 case BPF_ALU64 | BPF_DIV | BPF_K:
1352 case BPF_ALU64 | BPF_MOD | BPF_K:
1353 *to++ = BPF_ALU64_IMM(BPF_MOV, BPF_REG_AX, imm_rnd ^ from->imm);
1354 *to++ = BPF_ALU64_IMM(BPF_XOR, BPF_REG_AX, imm_rnd);
1355 *to++ = BPF_ALU64_REG_OFF(from->code, from->dst_reg, BPF_REG_AX, from->off);
1356 break;
1357
1358 case BPF_JMP | BPF_JEQ | BPF_K:
1359 case BPF_JMP | BPF_JNE | BPF_K:
1360 case BPF_JMP | BPF_JGT | BPF_K:
1361 case BPF_JMP | BPF_JLT | BPF_K:
1362 case BPF_JMP | BPF_JGE | BPF_K:
1363 case BPF_JMP | BPF_JLE | BPF_K:
1364 case BPF_JMP | BPF_JSGT | BPF_K:
1365 case BPF_JMP | BPF_JSLT | BPF_K:
1366 case BPF_JMP | BPF_JSGE | BPF_K:
1367 case BPF_JMP | BPF_JSLE | BPF_K:
1368 case BPF_JMP | BPF_JSET | BPF_K:
1369 /* Accommodate for extra offset in case of a backjump. */
1370 off = from->off;
1371 if (off < 0)
1372 off -= 2;
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_JMP_REG(from->code, from->dst_reg, BPF_REG_AX, off);
1376 break;
1377
1378 case BPF_JMP32 | BPF_JEQ | BPF_K:
1379 case BPF_JMP32 | BPF_JNE | BPF_K:
1380 case BPF_JMP32 | BPF_JGT | BPF_K:
1381 case BPF_JMP32 | BPF_JLT | BPF_K:
1382 case BPF_JMP32 | BPF_JGE | BPF_K:
1383 case BPF_JMP32 | BPF_JLE | BPF_K:
1384 case BPF_JMP32 | BPF_JSGT | BPF_K:
1385 case BPF_JMP32 | BPF_JSLT | BPF_K:
1386 case BPF_JMP32 | BPF_JSGE | BPF_K:
1387 case BPF_JMP32 | BPF_JSLE | BPF_K:
1388 case BPF_JMP32 | BPF_JSET | BPF_K:
1389 /* Accommodate for extra offset in case of a backjump. */
1390 off = from->off;
1391 if (off < 0)
1392 off -= 2;
1393 *to++ = BPF_ALU32_IMM(BPF_MOV, BPF_REG_AX, imm_rnd ^ from->imm);
1394 *to++ = BPF_ALU32_IMM(BPF_XOR, BPF_REG_AX, imm_rnd);
1395 *to++ = BPF_JMP32_REG(from->code, from->dst_reg, BPF_REG_AX,
1396 off);
1397 break;
1398
1399 case BPF_LD | BPF_IMM | BPF_DW:
1400 *to++ = BPF_ALU64_IMM(BPF_MOV, BPF_REG_AX, imm_rnd ^ aux[1].imm);
1401 *to++ = BPF_ALU64_IMM(BPF_XOR, BPF_REG_AX, imm_rnd);
1402 *to++ = BPF_ALU64_IMM(BPF_LSH, BPF_REG_AX, 32);
1403 *to++ = BPF_ALU64_REG(BPF_MOV, aux[0].dst_reg, BPF_REG_AX);
1404 break;
1405 case 0: /* Part 2 of BPF_LD | BPF_IMM | BPF_DW. */
1406 *to++ = BPF_ALU32_IMM(BPF_MOV, BPF_REG_AX, imm_rnd ^ aux[0].imm);
1407 *to++ = BPF_ALU32_IMM(BPF_XOR, BPF_REG_AX, imm_rnd);
1408 if (emit_zext)
1409 *to++ = BPF_ZEXT_REG(BPF_REG_AX);
1410 *to++ = BPF_ALU64_REG(BPF_OR, aux[0].dst_reg, BPF_REG_AX);
1411 break;
1412
1413 case BPF_ST | BPF_MEM | BPF_DW:
1414 case BPF_ST | BPF_MEM | BPF_W:
1415 case BPF_ST | BPF_MEM | BPF_H:
1416 case BPF_ST | BPF_MEM | BPF_B:
1417 *to++ = BPF_ALU64_IMM(BPF_MOV, BPF_REG_AX, imm_rnd ^ from->imm);
1418 *to++ = BPF_ALU64_IMM(BPF_XOR, BPF_REG_AX, imm_rnd);
1419 *to++ = BPF_STX_MEM(from->code, from->dst_reg, BPF_REG_AX, from->off);
1420 break;
1421 }
1422 out:
1423 return to - to_buff;
1424 }
1425
bpf_prog_clone_create(struct bpf_prog * fp_other,gfp_t gfp_extra_flags)1426 static struct bpf_prog *bpf_prog_clone_create(struct bpf_prog *fp_other,
1427 gfp_t gfp_extra_flags)
1428 {
1429 gfp_t gfp_flags = GFP_KERNEL | __GFP_ZERO | gfp_extra_flags;
1430 struct bpf_prog *fp;
1431
1432 fp = __vmalloc(fp_other->pages * PAGE_SIZE, gfp_flags);
1433 if (fp != NULL) {
1434 /* aux->prog still points to the fp_other one, so
1435 * when promoting the clone to the real program,
1436 * this still needs to be adapted.
1437 */
1438 memcpy(fp, fp_other, fp_other->pages * PAGE_SIZE);
1439 }
1440
1441 return fp;
1442 }
1443
bpf_prog_clone_free(struct bpf_prog * fp)1444 static void bpf_prog_clone_free(struct bpf_prog *fp)
1445 {
1446 /* aux was stolen by the other clone, so we cannot free
1447 * it from this path! It will be freed eventually by the
1448 * other program on release.
1449 *
1450 * At this point, we don't need a deferred release since
1451 * clone is guaranteed to not be locked.
1452 */
1453 fp->aux = NULL;
1454 fp->stats = NULL;
1455 fp->active = NULL;
1456 __bpf_prog_free(fp);
1457 }
1458
bpf_jit_prog_release_other(struct bpf_prog * fp,struct bpf_prog * fp_other)1459 void bpf_jit_prog_release_other(struct bpf_prog *fp, struct bpf_prog *fp_other)
1460 {
1461 /* We have to repoint aux->prog to self, as we don't
1462 * know whether fp here is the clone or the original.
1463 */
1464 fp->aux->prog = fp;
1465 bpf_prog_clone_free(fp_other);
1466 }
1467
bpf_jit_blind_constants(struct bpf_prog * prog)1468 struct bpf_prog *bpf_jit_blind_constants(struct bpf_prog *prog)
1469 {
1470 struct bpf_insn insn_buff[16], aux[2];
1471 struct bpf_prog *clone, *tmp;
1472 int insn_delta, insn_cnt;
1473 struct bpf_insn *insn;
1474 int i, rewritten;
1475
1476 if (!prog->blinding_requested || prog->blinded)
1477 return prog;
1478
1479 clone = bpf_prog_clone_create(prog, GFP_USER);
1480 if (!clone)
1481 return ERR_PTR(-ENOMEM);
1482
1483 insn_cnt = clone->len;
1484 insn = clone->insnsi;
1485
1486 for (i = 0; i < insn_cnt; i++, insn++) {
1487 if (bpf_pseudo_func(insn)) {
1488 /* ld_imm64 with an address of bpf subprog is not
1489 * a user controlled constant. Don't randomize it,
1490 * since it will conflict with jit_subprogs() logic.
1491 */
1492 insn++;
1493 i++;
1494 continue;
1495 }
1496
1497 /* We temporarily need to hold the original ld64 insn
1498 * so that we can still access the first part in the
1499 * second blinding run.
1500 */
1501 if (insn[0].code == (BPF_LD | BPF_IMM | BPF_DW) &&
1502 insn[1].code == 0)
1503 memcpy(aux, insn, sizeof(aux));
1504
1505 rewritten = bpf_jit_blind_insn(insn, aux, insn_buff,
1506 clone->aux->verifier_zext);
1507 if (!rewritten)
1508 continue;
1509
1510 tmp = bpf_patch_insn_single(clone, i, insn_buff, rewritten);
1511 if (IS_ERR(tmp)) {
1512 /* Patching may have repointed aux->prog during
1513 * realloc from the original one, so we need to
1514 * fix it up here on error.
1515 */
1516 bpf_jit_prog_release_other(prog, clone);
1517 return tmp;
1518 }
1519
1520 clone = tmp;
1521 insn_delta = rewritten - 1;
1522
1523 /* Walk new program and skip insns we just inserted. */
1524 insn = clone->insnsi + i + insn_delta;
1525 insn_cnt += insn_delta;
1526 i += insn_delta;
1527 }
1528
1529 clone->blinded = 1;
1530 return clone;
1531 }
1532 #endif /* CONFIG_BPF_JIT */
1533
1534 /* Base function for offset calculation. Needs to go into .text section,
1535 * therefore keeping it non-static as well; will also be used by JITs
1536 * anyway later on, so do not let the compiler omit it. This also needs
1537 * to go into kallsyms for correlation from e.g. bpftool, so naming
1538 * must not change.
1539 */
__bpf_call_base(u64 r1,u64 r2,u64 r3,u64 r4,u64 r5)1540 noinline u64 __bpf_call_base(u64 r1, u64 r2, u64 r3, u64 r4, u64 r5)
1541 {
1542 return 0;
1543 }
1544 EXPORT_SYMBOL_GPL(__bpf_call_base);
1545
1546 /* All UAPI available opcodes. */
1547 #define BPF_INSN_MAP(INSN_2, INSN_3) \
1548 /* 32 bit ALU operations. */ \
1549 /* Register based. */ \
1550 INSN_3(ALU, ADD, X), \
1551 INSN_3(ALU, SUB, X), \
1552 INSN_3(ALU, AND, X), \
1553 INSN_3(ALU, OR, X), \
1554 INSN_3(ALU, LSH, X), \
1555 INSN_3(ALU, RSH, X), \
1556 INSN_3(ALU, XOR, X), \
1557 INSN_3(ALU, MUL, X), \
1558 INSN_3(ALU, MOV, X), \
1559 INSN_3(ALU, ARSH, X), \
1560 INSN_3(ALU, DIV, X), \
1561 INSN_3(ALU, MOD, X), \
1562 INSN_2(ALU, NEG), \
1563 INSN_3(ALU, END, TO_BE), \
1564 INSN_3(ALU, END, TO_LE), \
1565 /* Immediate based. */ \
1566 INSN_3(ALU, ADD, K), \
1567 INSN_3(ALU, SUB, K), \
1568 INSN_3(ALU, AND, K), \
1569 INSN_3(ALU, OR, K), \
1570 INSN_3(ALU, LSH, K), \
1571 INSN_3(ALU, RSH, K), \
1572 INSN_3(ALU, XOR, K), \
1573 INSN_3(ALU, MUL, K), \
1574 INSN_3(ALU, MOV, K), \
1575 INSN_3(ALU, ARSH, K), \
1576 INSN_3(ALU, DIV, K), \
1577 INSN_3(ALU, MOD, K), \
1578 /* 64 bit ALU operations. */ \
1579 /* Register based. */ \
1580 INSN_3(ALU64, ADD, X), \
1581 INSN_3(ALU64, SUB, X), \
1582 INSN_3(ALU64, AND, X), \
1583 INSN_3(ALU64, OR, X), \
1584 INSN_3(ALU64, LSH, X), \
1585 INSN_3(ALU64, RSH, X), \
1586 INSN_3(ALU64, XOR, X), \
1587 INSN_3(ALU64, MUL, X), \
1588 INSN_3(ALU64, MOV, X), \
1589 INSN_3(ALU64, ARSH, X), \
1590 INSN_3(ALU64, DIV, X), \
1591 INSN_3(ALU64, MOD, X), \
1592 INSN_2(ALU64, NEG), \
1593 INSN_3(ALU64, END, TO_LE), \
1594 /* Immediate based. */ \
1595 INSN_3(ALU64, ADD, K), \
1596 INSN_3(ALU64, SUB, K), \
1597 INSN_3(ALU64, AND, K), \
1598 INSN_3(ALU64, OR, K), \
1599 INSN_3(ALU64, LSH, K), \
1600 INSN_3(ALU64, RSH, K), \
1601 INSN_3(ALU64, XOR, K), \
1602 INSN_3(ALU64, MUL, K), \
1603 INSN_3(ALU64, MOV, K), \
1604 INSN_3(ALU64, ARSH, K), \
1605 INSN_3(ALU64, DIV, K), \
1606 INSN_3(ALU64, MOD, K), \
1607 /* Call instruction. */ \
1608 INSN_2(JMP, CALL), \
1609 /* Exit instruction. */ \
1610 INSN_2(JMP, EXIT), \
1611 /* 32-bit Jump instructions. */ \
1612 /* Register based. */ \
1613 INSN_3(JMP32, JEQ, X), \
1614 INSN_3(JMP32, JNE, X), \
1615 INSN_3(JMP32, JGT, X), \
1616 INSN_3(JMP32, JLT, X), \
1617 INSN_3(JMP32, JGE, X), \
1618 INSN_3(JMP32, JLE, X), \
1619 INSN_3(JMP32, JSGT, X), \
1620 INSN_3(JMP32, JSLT, X), \
1621 INSN_3(JMP32, JSGE, X), \
1622 INSN_3(JMP32, JSLE, X), \
1623 INSN_3(JMP32, JSET, X), \
1624 /* Immediate based. */ \
1625 INSN_3(JMP32, JEQ, K), \
1626 INSN_3(JMP32, JNE, K), \
1627 INSN_3(JMP32, JGT, K), \
1628 INSN_3(JMP32, JLT, K), \
1629 INSN_3(JMP32, JGE, K), \
1630 INSN_3(JMP32, JLE, K), \
1631 INSN_3(JMP32, JSGT, K), \
1632 INSN_3(JMP32, JSLT, K), \
1633 INSN_3(JMP32, JSGE, K), \
1634 INSN_3(JMP32, JSLE, K), \
1635 INSN_3(JMP32, JSET, K), \
1636 /* Jump instructions. */ \
1637 /* Register based. */ \
1638 INSN_3(JMP, JEQ, X), \
1639 INSN_3(JMP, JNE, X), \
1640 INSN_3(JMP, JGT, X), \
1641 INSN_3(JMP, JLT, X), \
1642 INSN_3(JMP, JGE, X), \
1643 INSN_3(JMP, JLE, X), \
1644 INSN_3(JMP, JSGT, X), \
1645 INSN_3(JMP, JSLT, X), \
1646 INSN_3(JMP, JSGE, X), \
1647 INSN_3(JMP, JSLE, X), \
1648 INSN_3(JMP, JSET, X), \
1649 /* Immediate based. */ \
1650 INSN_3(JMP, JEQ, K), \
1651 INSN_3(JMP, JNE, K), \
1652 INSN_3(JMP, JGT, K), \
1653 INSN_3(JMP, JLT, K), \
1654 INSN_3(JMP, JGE, K), \
1655 INSN_3(JMP, JLE, K), \
1656 INSN_3(JMP, JSGT, K), \
1657 INSN_3(JMP, JSLT, K), \
1658 INSN_3(JMP, JSGE, K), \
1659 INSN_3(JMP, JSLE, K), \
1660 INSN_3(JMP, JSET, K), \
1661 INSN_2(JMP, JA), \
1662 INSN_2(JMP32, JA), \
1663 /* Store instructions. */ \
1664 /* Register based. */ \
1665 INSN_3(STX, MEM, B), \
1666 INSN_3(STX, MEM, H), \
1667 INSN_3(STX, MEM, W), \
1668 INSN_3(STX, MEM, DW), \
1669 INSN_3(STX, ATOMIC, W), \
1670 INSN_3(STX, ATOMIC, DW), \
1671 /* Immediate based. */ \
1672 INSN_3(ST, MEM, B), \
1673 INSN_3(ST, MEM, H), \
1674 INSN_3(ST, MEM, W), \
1675 INSN_3(ST, MEM, DW), \
1676 /* Load instructions. */ \
1677 /* Register based. */ \
1678 INSN_3(LDX, MEM, B), \
1679 INSN_3(LDX, MEM, H), \
1680 INSN_3(LDX, MEM, W), \
1681 INSN_3(LDX, MEM, DW), \
1682 INSN_3(LDX, MEMSX, B), \
1683 INSN_3(LDX, MEMSX, H), \
1684 INSN_3(LDX, MEMSX, W), \
1685 /* Immediate based. */ \
1686 INSN_3(LD, IMM, DW)
1687
bpf_opcode_in_insntable(u8 code)1688 bool bpf_opcode_in_insntable(u8 code)
1689 {
1690 #define BPF_INSN_2_TBL(x, y) [BPF_##x | BPF_##y] = true
1691 #define BPF_INSN_3_TBL(x, y, z) [BPF_##x | BPF_##y | BPF_##z] = true
1692 static const bool public_insntable[256] = {
1693 [0 ... 255] = false,
1694 /* Now overwrite non-defaults ... */
1695 BPF_INSN_MAP(BPF_INSN_2_TBL, BPF_INSN_3_TBL),
1696 /* UAPI exposed, but rewritten opcodes. cBPF carry-over. */
1697 [BPF_LD | BPF_ABS | BPF_B] = true,
1698 [BPF_LD | BPF_ABS | BPF_H] = true,
1699 [BPF_LD | BPF_ABS | BPF_W] = true,
1700 [BPF_LD | BPF_IND | BPF_B] = true,
1701 [BPF_LD | BPF_IND | BPF_H] = true,
1702 [BPF_LD | BPF_IND | BPF_W] = true,
1703 [BPF_JMP | BPF_JCOND] = true,
1704 };
1705 #undef BPF_INSN_3_TBL
1706 #undef BPF_INSN_2_TBL
1707 return public_insntable[code];
1708 }
1709
1710 #ifndef CONFIG_BPF_JIT_ALWAYS_ON
1711 /**
1712 * ___bpf_prog_run - run eBPF program on a given context
1713 * @regs: is the array of MAX_BPF_EXT_REG eBPF pseudo-registers
1714 * @insn: is the array of eBPF instructions
1715 *
1716 * Decode and execute eBPF instructions.
1717 *
1718 * Return: whatever value is in %BPF_R0 at program exit
1719 */
___bpf_prog_run(u64 * regs,const struct bpf_insn * insn)1720 static u64 ___bpf_prog_run(u64 *regs, const struct bpf_insn *insn)
1721 {
1722 #define BPF_INSN_2_LBL(x, y) [BPF_##x | BPF_##y] = &&x##_##y
1723 #define BPF_INSN_3_LBL(x, y, z) [BPF_##x | BPF_##y | BPF_##z] = &&x##_##y##_##z
1724 static const void * const jumptable[256] __annotate_jump_table = {
1725 [0 ... 255] = &&default_label,
1726 /* Now overwrite non-defaults ... */
1727 BPF_INSN_MAP(BPF_INSN_2_LBL, BPF_INSN_3_LBL),
1728 /* Non-UAPI available opcodes. */
1729 [BPF_JMP | BPF_CALL_ARGS] = &&JMP_CALL_ARGS,
1730 [BPF_JMP | BPF_TAIL_CALL] = &&JMP_TAIL_CALL,
1731 [BPF_ST | BPF_NOSPEC] = &&ST_NOSPEC,
1732 [BPF_LDX | BPF_PROBE_MEM | BPF_B] = &&LDX_PROBE_MEM_B,
1733 [BPF_LDX | BPF_PROBE_MEM | BPF_H] = &&LDX_PROBE_MEM_H,
1734 [BPF_LDX | BPF_PROBE_MEM | BPF_W] = &&LDX_PROBE_MEM_W,
1735 [BPF_LDX | BPF_PROBE_MEM | BPF_DW] = &&LDX_PROBE_MEM_DW,
1736 [BPF_LDX | BPF_PROBE_MEMSX | BPF_B] = &&LDX_PROBE_MEMSX_B,
1737 [BPF_LDX | BPF_PROBE_MEMSX | BPF_H] = &&LDX_PROBE_MEMSX_H,
1738 [BPF_LDX | BPF_PROBE_MEMSX | BPF_W] = &&LDX_PROBE_MEMSX_W,
1739 };
1740 #undef BPF_INSN_3_LBL
1741 #undef BPF_INSN_2_LBL
1742 u32 tail_call_cnt = 0;
1743
1744 #define CONT ({ insn++; goto select_insn; })
1745 #define CONT_JMP ({ insn++; goto select_insn; })
1746
1747 select_insn:
1748 goto *jumptable[insn->code];
1749
1750 /* Explicitly mask the register-based shift amounts with 63 or 31
1751 * to avoid undefined behavior. Normally this won't affect the
1752 * generated code, for example, in case of native 64 bit archs such
1753 * as x86-64 or arm64, the compiler is optimizing the AND away for
1754 * the interpreter. In case of JITs, each of the JIT backends compiles
1755 * the BPF shift operations to machine instructions which produce
1756 * implementation-defined results in such a case; the resulting
1757 * contents of the register may be arbitrary, but program behaviour
1758 * as a whole remains defined. In other words, in case of JIT backends,
1759 * the AND must /not/ be added to the emitted LSH/RSH/ARSH translation.
1760 */
1761 /* ALU (shifts) */
1762 #define SHT(OPCODE, OP) \
1763 ALU64_##OPCODE##_X: \
1764 DST = DST OP (SRC & 63); \
1765 CONT; \
1766 ALU_##OPCODE##_X: \
1767 DST = (u32) DST OP ((u32) SRC & 31); \
1768 CONT; \
1769 ALU64_##OPCODE##_K: \
1770 DST = DST OP IMM; \
1771 CONT; \
1772 ALU_##OPCODE##_K: \
1773 DST = (u32) DST OP (u32) IMM; \
1774 CONT;
1775 /* ALU (rest) */
1776 #define ALU(OPCODE, OP) \
1777 ALU64_##OPCODE##_X: \
1778 DST = DST OP SRC; \
1779 CONT; \
1780 ALU_##OPCODE##_X: \
1781 DST = (u32) DST OP (u32) SRC; \
1782 CONT; \
1783 ALU64_##OPCODE##_K: \
1784 DST = DST OP IMM; \
1785 CONT; \
1786 ALU_##OPCODE##_K: \
1787 DST = (u32) DST OP (u32) IMM; \
1788 CONT;
1789 ALU(ADD, +)
1790 ALU(SUB, -)
1791 ALU(AND, &)
1792 ALU(OR, |)
1793 ALU(XOR, ^)
1794 ALU(MUL, *)
1795 SHT(LSH, <<)
1796 SHT(RSH, >>)
1797 #undef SHT
1798 #undef ALU
1799 ALU_NEG:
1800 DST = (u32) -DST;
1801 CONT;
1802 ALU64_NEG:
1803 DST = -DST;
1804 CONT;
1805 ALU_MOV_X:
1806 switch (OFF) {
1807 case 0:
1808 DST = (u32) SRC;
1809 break;
1810 case 8:
1811 DST = (u32)(s8) SRC;
1812 break;
1813 case 16:
1814 DST = (u32)(s16) SRC;
1815 break;
1816 }
1817 CONT;
1818 ALU_MOV_K:
1819 DST = (u32) IMM;
1820 CONT;
1821 ALU64_MOV_X:
1822 switch (OFF) {
1823 case 0:
1824 DST = SRC;
1825 break;
1826 case 8:
1827 DST = (s8) SRC;
1828 break;
1829 case 16:
1830 DST = (s16) SRC;
1831 break;
1832 case 32:
1833 DST = (s32) SRC;
1834 break;
1835 }
1836 CONT;
1837 ALU64_MOV_K:
1838 DST = IMM;
1839 CONT;
1840 LD_IMM_DW:
1841 DST = (u64) (u32) insn[0].imm | ((u64) (u32) insn[1].imm) << 32;
1842 insn++;
1843 CONT;
1844 ALU_ARSH_X:
1845 DST = (u64) (u32) (((s32) DST) >> (SRC & 31));
1846 CONT;
1847 ALU_ARSH_K:
1848 DST = (u64) (u32) (((s32) DST) >> IMM);
1849 CONT;
1850 ALU64_ARSH_X:
1851 (*(s64 *) &DST) >>= (SRC & 63);
1852 CONT;
1853 ALU64_ARSH_K:
1854 (*(s64 *) &DST) >>= IMM;
1855 CONT;
1856 ALU64_MOD_X:
1857 switch (OFF) {
1858 case 0:
1859 div64_u64_rem(DST, SRC, &AX);
1860 DST = AX;
1861 break;
1862 case 1:
1863 AX = div64_s64(DST, SRC);
1864 DST = DST - AX * SRC;
1865 break;
1866 }
1867 CONT;
1868 ALU_MOD_X:
1869 switch (OFF) {
1870 case 0:
1871 AX = (u32) DST;
1872 DST = do_div(AX, (u32) SRC);
1873 break;
1874 case 1:
1875 AX = abs((s32)DST);
1876 AX = do_div(AX, abs((s32)SRC));
1877 if ((s32)DST < 0)
1878 DST = (u32)-AX;
1879 else
1880 DST = (u32)AX;
1881 break;
1882 }
1883 CONT;
1884 ALU64_MOD_K:
1885 switch (OFF) {
1886 case 0:
1887 div64_u64_rem(DST, IMM, &AX);
1888 DST = AX;
1889 break;
1890 case 1:
1891 AX = div64_s64(DST, IMM);
1892 DST = DST - AX * IMM;
1893 break;
1894 }
1895 CONT;
1896 ALU_MOD_K:
1897 switch (OFF) {
1898 case 0:
1899 AX = (u32) DST;
1900 DST = do_div(AX, (u32) IMM);
1901 break;
1902 case 1:
1903 AX = abs((s32)DST);
1904 AX = do_div(AX, abs((s32)IMM));
1905 if ((s32)DST < 0)
1906 DST = (u32)-AX;
1907 else
1908 DST = (u32)AX;
1909 break;
1910 }
1911 CONT;
1912 ALU64_DIV_X:
1913 switch (OFF) {
1914 case 0:
1915 DST = div64_u64(DST, SRC);
1916 break;
1917 case 1:
1918 DST = div64_s64(DST, SRC);
1919 break;
1920 }
1921 CONT;
1922 ALU_DIV_X:
1923 switch (OFF) {
1924 case 0:
1925 AX = (u32) DST;
1926 do_div(AX, (u32) SRC);
1927 DST = (u32) AX;
1928 break;
1929 case 1:
1930 AX = abs((s32)DST);
1931 do_div(AX, abs((s32)SRC));
1932 if (((s32)DST < 0) == ((s32)SRC < 0))
1933 DST = (u32)AX;
1934 else
1935 DST = (u32)-AX;
1936 break;
1937 }
1938 CONT;
1939 ALU64_DIV_K:
1940 switch (OFF) {
1941 case 0:
1942 DST = div64_u64(DST, IMM);
1943 break;
1944 case 1:
1945 DST = div64_s64(DST, IMM);
1946 break;
1947 }
1948 CONT;
1949 ALU_DIV_K:
1950 switch (OFF) {
1951 case 0:
1952 AX = (u32) DST;
1953 do_div(AX, (u32) IMM);
1954 DST = (u32) AX;
1955 break;
1956 case 1:
1957 AX = abs((s32)DST);
1958 do_div(AX, abs((s32)IMM));
1959 if (((s32)DST < 0) == ((s32)IMM < 0))
1960 DST = (u32)AX;
1961 else
1962 DST = (u32)-AX;
1963 break;
1964 }
1965 CONT;
1966 ALU_END_TO_BE:
1967 switch (IMM) {
1968 case 16:
1969 DST = (__force u16) cpu_to_be16(DST);
1970 break;
1971 case 32:
1972 DST = (__force u32) cpu_to_be32(DST);
1973 break;
1974 case 64:
1975 DST = (__force u64) cpu_to_be64(DST);
1976 break;
1977 }
1978 CONT;
1979 ALU_END_TO_LE:
1980 switch (IMM) {
1981 case 16:
1982 DST = (__force u16) cpu_to_le16(DST);
1983 break;
1984 case 32:
1985 DST = (__force u32) cpu_to_le32(DST);
1986 break;
1987 case 64:
1988 DST = (__force u64) cpu_to_le64(DST);
1989 break;
1990 }
1991 CONT;
1992 ALU64_END_TO_LE:
1993 switch (IMM) {
1994 case 16:
1995 DST = (__force u16) __swab16(DST);
1996 break;
1997 case 32:
1998 DST = (__force u32) __swab32(DST);
1999 break;
2000 case 64:
2001 DST = (__force u64) __swab64(DST);
2002 break;
2003 }
2004 CONT;
2005
2006 /* CALL */
2007 JMP_CALL:
2008 /* Function call scratches BPF_R1-BPF_R5 registers,
2009 * preserves BPF_R6-BPF_R9, and stores return value
2010 * into BPF_R0.
2011 */
2012 BPF_R0 = (__bpf_call_base + insn->imm)(BPF_R1, BPF_R2, BPF_R3,
2013 BPF_R4, BPF_R5);
2014 CONT;
2015
2016 JMP_CALL_ARGS:
2017 BPF_R0 = (__bpf_call_base_args + insn->imm)(BPF_R1, BPF_R2,
2018 BPF_R3, BPF_R4,
2019 BPF_R5,
2020 insn + insn->off + 1);
2021 CONT;
2022
2023 JMP_TAIL_CALL: {
2024 struct bpf_map *map = (struct bpf_map *) (unsigned long) BPF_R2;
2025 struct bpf_array *array = container_of(map, struct bpf_array, map);
2026 struct bpf_prog *prog;
2027 u32 index = BPF_R3;
2028
2029 if (unlikely(index >= array->map.max_entries))
2030 goto out;
2031
2032 if (unlikely(tail_call_cnt >= MAX_TAIL_CALL_CNT))
2033 goto out;
2034
2035 tail_call_cnt++;
2036
2037 prog = READ_ONCE(array->ptrs[index]);
2038 if (!prog)
2039 goto out;
2040
2041 /* ARG1 at this point is guaranteed to point to CTX from
2042 * the verifier side due to the fact that the tail call is
2043 * handled like a helper, that is, bpf_tail_call_proto,
2044 * where arg1_type is ARG_PTR_TO_CTX.
2045 */
2046 insn = prog->insnsi;
2047 goto select_insn;
2048 out:
2049 CONT;
2050 }
2051 JMP_JA:
2052 insn += insn->off;
2053 CONT;
2054 JMP32_JA:
2055 insn += insn->imm;
2056 CONT;
2057 JMP_EXIT:
2058 return BPF_R0;
2059 /* JMP */
2060 #define COND_JMP(SIGN, OPCODE, CMP_OP) \
2061 JMP_##OPCODE##_X: \
2062 if ((SIGN##64) DST CMP_OP (SIGN##64) SRC) { \
2063 insn += insn->off; \
2064 CONT_JMP; \
2065 } \
2066 CONT; \
2067 JMP32_##OPCODE##_X: \
2068 if ((SIGN##32) DST CMP_OP (SIGN##32) SRC) { \
2069 insn += insn->off; \
2070 CONT_JMP; \
2071 } \
2072 CONT; \
2073 JMP_##OPCODE##_K: \
2074 if ((SIGN##64) DST CMP_OP (SIGN##64) IMM) { \
2075 insn += insn->off; \
2076 CONT_JMP; \
2077 } \
2078 CONT; \
2079 JMP32_##OPCODE##_K: \
2080 if ((SIGN##32) DST CMP_OP (SIGN##32) IMM) { \
2081 insn += insn->off; \
2082 CONT_JMP; \
2083 } \
2084 CONT;
2085 COND_JMP(u, JEQ, ==)
2086 COND_JMP(u, JNE, !=)
2087 COND_JMP(u, JGT, >)
2088 COND_JMP(u, JLT, <)
2089 COND_JMP(u, JGE, >=)
2090 COND_JMP(u, JLE, <=)
2091 COND_JMP(u, JSET, &)
2092 COND_JMP(s, JSGT, >)
2093 COND_JMP(s, JSLT, <)
2094 COND_JMP(s, JSGE, >=)
2095 COND_JMP(s, JSLE, <=)
2096 #undef COND_JMP
2097 /* ST, STX and LDX*/
2098 ST_NOSPEC:
2099 /* Speculation barrier for mitigating Speculative Store Bypass.
2100 * In case of arm64, we rely on the firmware mitigation as
2101 * controlled via the ssbd kernel parameter. Whenever the
2102 * mitigation is enabled, it works for all of the kernel code
2103 * with no need to provide any additional instructions here.
2104 * In case of x86, we use 'lfence' insn for mitigation. We
2105 * reuse preexisting logic from Spectre v1 mitigation that
2106 * happens to produce the required code on x86 for v4 as well.
2107 */
2108 barrier_nospec();
2109 CONT;
2110 #define LDST(SIZEOP, SIZE) \
2111 STX_MEM_##SIZEOP: \
2112 *(SIZE *)(unsigned long) (DST + insn->off) = SRC; \
2113 CONT; \
2114 ST_MEM_##SIZEOP: \
2115 *(SIZE *)(unsigned long) (DST + insn->off) = IMM; \
2116 CONT; \
2117 LDX_MEM_##SIZEOP: \
2118 DST = *(SIZE *)(unsigned long) (SRC + insn->off); \
2119 CONT; \
2120 LDX_PROBE_MEM_##SIZEOP: \
2121 bpf_probe_read_kernel_common(&DST, sizeof(SIZE), \
2122 (const void *)(long) (SRC + insn->off)); \
2123 DST = *((SIZE *)&DST); \
2124 CONT;
2125
2126 LDST(B, u8)
2127 LDST(H, u16)
2128 LDST(W, u32)
2129 LDST(DW, u64)
2130 #undef LDST
2131
2132 #define LDSX(SIZEOP, SIZE) \
2133 LDX_MEMSX_##SIZEOP: \
2134 DST = *(SIZE *)(unsigned long) (SRC + insn->off); \
2135 CONT; \
2136 LDX_PROBE_MEMSX_##SIZEOP: \
2137 bpf_probe_read_kernel_common(&DST, sizeof(SIZE), \
2138 (const void *)(long) (SRC + insn->off)); \
2139 DST = *((SIZE *)&DST); \
2140 CONT;
2141
2142 LDSX(B, s8)
2143 LDSX(H, s16)
2144 LDSX(W, s32)
2145 #undef LDSX
2146
2147 #define ATOMIC_ALU_OP(BOP, KOP) \
2148 case BOP: \
2149 if (BPF_SIZE(insn->code) == BPF_W) \
2150 atomic_##KOP((u32) SRC, (atomic_t *)(unsigned long) \
2151 (DST + insn->off)); \
2152 else \
2153 atomic64_##KOP((u64) SRC, (atomic64_t *)(unsigned long) \
2154 (DST + insn->off)); \
2155 break; \
2156 case BOP | BPF_FETCH: \
2157 if (BPF_SIZE(insn->code) == BPF_W) \
2158 SRC = (u32) atomic_fetch_##KOP( \
2159 (u32) SRC, \
2160 (atomic_t *)(unsigned long) (DST + insn->off)); \
2161 else \
2162 SRC = (u64) atomic64_fetch_##KOP( \
2163 (u64) SRC, \
2164 (atomic64_t *)(unsigned long) (DST + insn->off)); \
2165 break;
2166
2167 STX_ATOMIC_DW:
2168 STX_ATOMIC_W:
2169 switch (IMM) {
2170 ATOMIC_ALU_OP(BPF_ADD, add)
2171 ATOMIC_ALU_OP(BPF_AND, and)
2172 ATOMIC_ALU_OP(BPF_OR, or)
2173 ATOMIC_ALU_OP(BPF_XOR, xor)
2174 #undef ATOMIC_ALU_OP
2175
2176 case BPF_XCHG:
2177 if (BPF_SIZE(insn->code) == BPF_W)
2178 SRC = (u32) atomic_xchg(
2179 (atomic_t *)(unsigned long) (DST + insn->off),
2180 (u32) SRC);
2181 else
2182 SRC = (u64) atomic64_xchg(
2183 (atomic64_t *)(unsigned long) (DST + insn->off),
2184 (u64) SRC);
2185 break;
2186 case BPF_CMPXCHG:
2187 if (BPF_SIZE(insn->code) == BPF_W)
2188 BPF_R0 = (u32) atomic_cmpxchg(
2189 (atomic_t *)(unsigned long) (DST + insn->off),
2190 (u32) BPF_R0, (u32) SRC);
2191 else
2192 BPF_R0 = (u64) atomic64_cmpxchg(
2193 (atomic64_t *)(unsigned long) (DST + insn->off),
2194 (u64) BPF_R0, (u64) SRC);
2195 break;
2196
2197 default:
2198 goto default_label;
2199 }
2200 CONT;
2201
2202 default_label:
2203 /* If we ever reach this, we have a bug somewhere. Die hard here
2204 * instead of just returning 0; we could be somewhere in a subprog,
2205 * so execution could continue otherwise which we do /not/ want.
2206 *
2207 * Note, verifier whitelists all opcodes in bpf_opcode_in_insntable().
2208 */
2209 pr_warn("BPF interpreter: unknown opcode %02x (imm: 0x%x)\n",
2210 insn->code, insn->imm);
2211 BUG_ON(1);
2212 return 0;
2213 }
2214
2215 #define PROG_NAME(stack_size) __bpf_prog_run##stack_size
2216 #define DEFINE_BPF_PROG_RUN(stack_size) \
2217 static unsigned int PROG_NAME(stack_size)(const void *ctx, const struct bpf_insn *insn) \
2218 { \
2219 u64 stack[stack_size / sizeof(u64)]; \
2220 u64 regs[MAX_BPF_EXT_REG] = {}; \
2221 \
2222 kmsan_unpoison_memory(stack, sizeof(stack)); \
2223 FP = (u64) (unsigned long) &stack[ARRAY_SIZE(stack)]; \
2224 ARG1 = (u64) (unsigned long) ctx; \
2225 return ___bpf_prog_run(regs, insn); \
2226 }
2227
2228 #define PROG_NAME_ARGS(stack_size) __bpf_prog_run_args##stack_size
2229 #define DEFINE_BPF_PROG_RUN_ARGS(stack_size) \
2230 static u64 PROG_NAME_ARGS(stack_size)(u64 r1, u64 r2, u64 r3, u64 r4, u64 r5, \
2231 const struct bpf_insn *insn) \
2232 { \
2233 u64 stack[stack_size / sizeof(u64)]; \
2234 u64 regs[MAX_BPF_EXT_REG]; \
2235 \
2236 kmsan_unpoison_memory(stack, sizeof(stack)); \
2237 FP = (u64) (unsigned long) &stack[ARRAY_SIZE(stack)]; \
2238 BPF_R1 = r1; \
2239 BPF_R2 = r2; \
2240 BPF_R3 = r3; \
2241 BPF_R4 = r4; \
2242 BPF_R5 = r5; \
2243 return ___bpf_prog_run(regs, insn); \
2244 }
2245
2246 #define EVAL1(FN, X) FN(X)
2247 #define EVAL2(FN, X, Y...) FN(X) EVAL1(FN, Y)
2248 #define EVAL3(FN, X, Y...) FN(X) EVAL2(FN, Y)
2249 #define EVAL4(FN, X, Y...) FN(X) EVAL3(FN, Y)
2250 #define EVAL5(FN, X, Y...) FN(X) EVAL4(FN, Y)
2251 #define EVAL6(FN, X, Y...) FN(X) EVAL5(FN, Y)
2252
2253 EVAL6(DEFINE_BPF_PROG_RUN, 32, 64, 96, 128, 160, 192);
2254 EVAL6(DEFINE_BPF_PROG_RUN, 224, 256, 288, 320, 352, 384);
2255 EVAL4(DEFINE_BPF_PROG_RUN, 416, 448, 480, 512);
2256
2257 EVAL6(DEFINE_BPF_PROG_RUN_ARGS, 32, 64, 96, 128, 160, 192);
2258 EVAL6(DEFINE_BPF_PROG_RUN_ARGS, 224, 256, 288, 320, 352, 384);
2259 EVAL4(DEFINE_BPF_PROG_RUN_ARGS, 416, 448, 480, 512);
2260
2261 #define PROG_NAME_LIST(stack_size) PROG_NAME(stack_size),
2262
2263 static unsigned int (*interpreters[])(const void *ctx,
2264 const struct bpf_insn *insn) = {
2265 EVAL6(PROG_NAME_LIST, 32, 64, 96, 128, 160, 192)
2266 EVAL6(PROG_NAME_LIST, 224, 256, 288, 320, 352, 384)
2267 EVAL4(PROG_NAME_LIST, 416, 448, 480, 512)
2268 };
2269 #undef PROG_NAME_LIST
2270 #define PROG_NAME_LIST(stack_size) PROG_NAME_ARGS(stack_size),
2271 static __maybe_unused
2272 u64 (*interpreters_args[])(u64 r1, u64 r2, u64 r3, u64 r4, u64 r5,
2273 const struct bpf_insn *insn) = {
2274 EVAL6(PROG_NAME_LIST, 32, 64, 96, 128, 160, 192)
2275 EVAL6(PROG_NAME_LIST, 224, 256, 288, 320, 352, 384)
2276 EVAL4(PROG_NAME_LIST, 416, 448, 480, 512)
2277 };
2278 #undef PROG_NAME_LIST
2279
2280 #ifdef CONFIG_BPF_SYSCALL
bpf_patch_call_args(struct bpf_insn * insn,u32 stack_depth)2281 void bpf_patch_call_args(struct bpf_insn *insn, u32 stack_depth)
2282 {
2283 stack_depth = max_t(u32, stack_depth, 1);
2284 insn->off = (s16) insn->imm;
2285 insn->imm = interpreters_args[(round_up(stack_depth, 32) / 32) - 1] -
2286 __bpf_call_base_args;
2287 insn->code = BPF_JMP | BPF_CALL_ARGS;
2288 }
2289 #endif
2290 #else
__bpf_prog_ret0_warn(const void * ctx,const struct bpf_insn * insn)2291 static unsigned int __bpf_prog_ret0_warn(const void *ctx,
2292 const struct bpf_insn *insn)
2293 {
2294 /* If this handler ever gets executed, then BPF_JIT_ALWAYS_ON
2295 * is not working properly, so warn about it!
2296 */
2297 WARN_ON_ONCE(1);
2298 return 0;
2299 }
2300 #endif
2301
bpf_prog_map_compatible(struct bpf_map * map,const struct bpf_prog * fp)2302 bool bpf_prog_map_compatible(struct bpf_map *map,
2303 const struct bpf_prog *fp)
2304 {
2305 enum bpf_prog_type prog_type = resolve_prog_type(fp);
2306 bool ret;
2307
2308 if (fp->kprobe_override)
2309 return false;
2310
2311 /* XDP programs inserted into maps are not guaranteed to run on
2312 * a particular netdev (and can run outside driver context entirely
2313 * in the case of devmap and cpumap). Until device checks
2314 * are implemented, prohibit adding dev-bound programs to program maps.
2315 */
2316 if (bpf_prog_is_dev_bound(fp->aux))
2317 return false;
2318
2319 spin_lock(&map->owner.lock);
2320 if (!map->owner.type) {
2321 /* There's no owner yet where we could check for
2322 * compatibility.
2323 */
2324 map->owner.type = prog_type;
2325 map->owner.jited = fp->jited;
2326 map->owner.xdp_has_frags = fp->aux->xdp_has_frags;
2327 ret = true;
2328 } else {
2329 ret = map->owner.type == prog_type &&
2330 map->owner.jited == fp->jited &&
2331 map->owner.xdp_has_frags == fp->aux->xdp_has_frags;
2332 }
2333 spin_unlock(&map->owner.lock);
2334
2335 return ret;
2336 }
2337
bpf_check_tail_call(const struct bpf_prog * fp)2338 static int bpf_check_tail_call(const struct bpf_prog *fp)
2339 {
2340 struct bpf_prog_aux *aux = fp->aux;
2341 int i, ret = 0;
2342
2343 mutex_lock(&aux->used_maps_mutex);
2344 for (i = 0; i < aux->used_map_cnt; i++) {
2345 struct bpf_map *map = aux->used_maps[i];
2346
2347 if (!map_type_contains_progs(map))
2348 continue;
2349
2350 if (!bpf_prog_map_compatible(map, fp)) {
2351 ret = -EINVAL;
2352 goto out;
2353 }
2354 }
2355
2356 out:
2357 mutex_unlock(&aux->used_maps_mutex);
2358 return ret;
2359 }
2360
bpf_prog_select_func(struct bpf_prog * fp)2361 static void bpf_prog_select_func(struct bpf_prog *fp)
2362 {
2363 #ifndef CONFIG_BPF_JIT_ALWAYS_ON
2364 u32 stack_depth = max_t(u32, fp->aux->stack_depth, 1);
2365
2366 fp->bpf_func = interpreters[(round_up(stack_depth, 32) / 32) - 1];
2367 #else
2368 fp->bpf_func = __bpf_prog_ret0_warn;
2369 #endif
2370 }
2371
2372 /**
2373 * bpf_prog_select_runtime - select exec runtime for BPF program
2374 * @fp: bpf_prog populated with BPF program
2375 * @err: pointer to error variable
2376 *
2377 * Try to JIT eBPF program, if JIT is not available, use interpreter.
2378 * The BPF program will be executed via bpf_prog_run() function.
2379 *
2380 * Return: the &fp argument along with &err set to 0 for success or
2381 * a negative errno code on failure
2382 */
bpf_prog_select_runtime(struct bpf_prog * fp,int * err)2383 struct bpf_prog *bpf_prog_select_runtime(struct bpf_prog *fp, int *err)
2384 {
2385 /* In case of BPF to BPF calls, verifier did all the prep
2386 * work with regards to JITing, etc.
2387 */
2388 bool jit_needed = false;
2389
2390 if (fp->bpf_func)
2391 goto finalize;
2392
2393 if (IS_ENABLED(CONFIG_BPF_JIT_ALWAYS_ON) ||
2394 bpf_prog_has_kfunc_call(fp))
2395 jit_needed = true;
2396
2397 bpf_prog_select_func(fp);
2398
2399 /* eBPF JITs can rewrite the program in case constant
2400 * blinding is active. However, in case of error during
2401 * blinding, bpf_int_jit_compile() must always return a
2402 * valid program, which in this case would simply not
2403 * be JITed, but falls back to the interpreter.
2404 */
2405 if (!bpf_prog_is_offloaded(fp->aux)) {
2406 *err = bpf_prog_alloc_jited_linfo(fp);
2407 if (*err)
2408 return fp;
2409
2410 fp = bpf_int_jit_compile(fp);
2411 bpf_prog_jit_attempt_done(fp);
2412 if (!fp->jited && jit_needed) {
2413 *err = -ENOTSUPP;
2414 return fp;
2415 }
2416 } else {
2417 *err = bpf_prog_offload_compile(fp);
2418 if (*err)
2419 return fp;
2420 }
2421
2422 finalize:
2423 *err = bpf_prog_lock_ro(fp);
2424 if (*err)
2425 return fp;
2426
2427 /* The tail call compatibility check can only be done at
2428 * this late stage as we need to determine, if we deal
2429 * with JITed or non JITed program concatenations and not
2430 * all eBPF JITs might immediately support all features.
2431 */
2432 *err = bpf_check_tail_call(fp);
2433
2434 return fp;
2435 }
2436 EXPORT_SYMBOL_GPL(bpf_prog_select_runtime);
2437
__bpf_prog_ret1(const void * ctx,const struct bpf_insn * insn)2438 static unsigned int __bpf_prog_ret1(const void *ctx,
2439 const struct bpf_insn *insn)
2440 {
2441 return 1;
2442 }
2443
2444 static struct bpf_prog_dummy {
2445 struct bpf_prog prog;
2446 } dummy_bpf_prog = {
2447 .prog = {
2448 .bpf_func = __bpf_prog_ret1,
2449 },
2450 };
2451
2452 struct bpf_empty_prog_array bpf_empty_prog_array = {
2453 .null_prog = NULL,
2454 };
2455 EXPORT_SYMBOL(bpf_empty_prog_array);
2456
bpf_prog_array_alloc(u32 prog_cnt,gfp_t flags)2457 struct bpf_prog_array *bpf_prog_array_alloc(u32 prog_cnt, gfp_t flags)
2458 {
2459 struct bpf_prog_array *p;
2460
2461 if (prog_cnt)
2462 p = kzalloc(struct_size(p, items, prog_cnt + 1), flags);
2463 else
2464 p = &bpf_empty_prog_array.hdr;
2465
2466 return p;
2467 }
2468
bpf_prog_array_free(struct bpf_prog_array * progs)2469 void bpf_prog_array_free(struct bpf_prog_array *progs)
2470 {
2471 if (!progs || progs == &bpf_empty_prog_array.hdr)
2472 return;
2473 kfree_rcu(progs, rcu);
2474 }
2475
__bpf_prog_array_free_sleepable_cb(struct rcu_head * rcu)2476 static void __bpf_prog_array_free_sleepable_cb(struct rcu_head *rcu)
2477 {
2478 struct bpf_prog_array *progs;
2479
2480 /* If RCU Tasks Trace grace period implies RCU grace period, there is
2481 * no need to call kfree_rcu(), just call kfree() directly.
2482 */
2483 progs = container_of(rcu, struct bpf_prog_array, rcu);
2484 if (rcu_trace_implies_rcu_gp())
2485 kfree(progs);
2486 else
2487 kfree_rcu(progs, rcu);
2488 }
2489
bpf_prog_array_free_sleepable(struct bpf_prog_array * progs)2490 void bpf_prog_array_free_sleepable(struct bpf_prog_array *progs)
2491 {
2492 if (!progs || progs == &bpf_empty_prog_array.hdr)
2493 return;
2494 call_rcu_tasks_trace(&progs->rcu, __bpf_prog_array_free_sleepable_cb);
2495 }
2496
bpf_prog_array_length(struct bpf_prog_array * array)2497 int bpf_prog_array_length(struct bpf_prog_array *array)
2498 {
2499 struct bpf_prog_array_item *item;
2500 u32 cnt = 0;
2501
2502 for (item = array->items; item->prog; item++)
2503 if (item->prog != &dummy_bpf_prog.prog)
2504 cnt++;
2505 return cnt;
2506 }
2507
bpf_prog_array_is_empty(struct bpf_prog_array * array)2508 bool bpf_prog_array_is_empty(struct bpf_prog_array *array)
2509 {
2510 struct bpf_prog_array_item *item;
2511
2512 for (item = array->items; item->prog; item++)
2513 if (item->prog != &dummy_bpf_prog.prog)
2514 return false;
2515 return true;
2516 }
2517
bpf_prog_array_copy_core(struct bpf_prog_array * array,u32 * prog_ids,u32 request_cnt)2518 static bool bpf_prog_array_copy_core(struct bpf_prog_array *array,
2519 u32 *prog_ids,
2520 u32 request_cnt)
2521 {
2522 struct bpf_prog_array_item *item;
2523 int i = 0;
2524
2525 for (item = array->items; item->prog; item++) {
2526 if (item->prog == &dummy_bpf_prog.prog)
2527 continue;
2528 prog_ids[i] = item->prog->aux->id;
2529 if (++i == request_cnt) {
2530 item++;
2531 break;
2532 }
2533 }
2534
2535 return !!(item->prog);
2536 }
2537
bpf_prog_array_copy_to_user(struct bpf_prog_array * array,__u32 __user * prog_ids,u32 cnt)2538 int bpf_prog_array_copy_to_user(struct bpf_prog_array *array,
2539 __u32 __user *prog_ids, u32 cnt)
2540 {
2541 unsigned long err = 0;
2542 bool nospc;
2543 u32 *ids;
2544
2545 /* users of this function are doing:
2546 * cnt = bpf_prog_array_length();
2547 * if (cnt > 0)
2548 * bpf_prog_array_copy_to_user(..., cnt);
2549 * so below kcalloc doesn't need extra cnt > 0 check.
2550 */
2551 ids = kcalloc(cnt, sizeof(u32), GFP_USER | __GFP_NOWARN);
2552 if (!ids)
2553 return -ENOMEM;
2554 nospc = bpf_prog_array_copy_core(array, ids, cnt);
2555 err = copy_to_user(prog_ids, ids, cnt * sizeof(u32));
2556 kfree(ids);
2557 if (err)
2558 return -EFAULT;
2559 if (nospc)
2560 return -ENOSPC;
2561 return 0;
2562 }
2563
bpf_prog_array_delete_safe(struct bpf_prog_array * array,struct bpf_prog * old_prog)2564 void bpf_prog_array_delete_safe(struct bpf_prog_array *array,
2565 struct bpf_prog *old_prog)
2566 {
2567 struct bpf_prog_array_item *item;
2568
2569 for (item = array->items; item->prog; item++)
2570 if (item->prog == old_prog) {
2571 WRITE_ONCE(item->prog, &dummy_bpf_prog.prog);
2572 break;
2573 }
2574 }
2575
2576 /**
2577 * bpf_prog_array_delete_safe_at() - Replaces the program at the given
2578 * index into the program array with
2579 * a dummy no-op program.
2580 * @array: a bpf_prog_array
2581 * @index: the index of the program to replace
2582 *
2583 * Skips over dummy programs, by not counting them, when calculating
2584 * the position of the program to replace.
2585 *
2586 * Return:
2587 * * 0 - Success
2588 * * -EINVAL - Invalid index value. Must be a non-negative integer.
2589 * * -ENOENT - Index out of range
2590 */
bpf_prog_array_delete_safe_at(struct bpf_prog_array * array,int index)2591 int bpf_prog_array_delete_safe_at(struct bpf_prog_array *array, int index)
2592 {
2593 return bpf_prog_array_update_at(array, index, &dummy_bpf_prog.prog);
2594 }
2595
2596 /**
2597 * bpf_prog_array_update_at() - Updates the program at the given index
2598 * into the program array.
2599 * @array: a bpf_prog_array
2600 * @index: the index of the program to update
2601 * @prog: the program to insert into the array
2602 *
2603 * Skips over dummy programs, by not counting them, when calculating
2604 * the position of the program to update.
2605 *
2606 * Return:
2607 * * 0 - Success
2608 * * -EINVAL - Invalid index value. Must be a non-negative integer.
2609 * * -ENOENT - Index out of range
2610 */
bpf_prog_array_update_at(struct bpf_prog_array * array,int index,struct bpf_prog * prog)2611 int bpf_prog_array_update_at(struct bpf_prog_array *array, int index,
2612 struct bpf_prog *prog)
2613 {
2614 struct bpf_prog_array_item *item;
2615
2616 if (unlikely(index < 0))
2617 return -EINVAL;
2618
2619 for (item = array->items; item->prog; item++) {
2620 if (item->prog == &dummy_bpf_prog.prog)
2621 continue;
2622 if (!index) {
2623 WRITE_ONCE(item->prog, prog);
2624 return 0;
2625 }
2626 index--;
2627 }
2628 return -ENOENT;
2629 }
2630
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)2631 int bpf_prog_array_copy(struct bpf_prog_array *old_array,
2632 struct bpf_prog *exclude_prog,
2633 struct bpf_prog *include_prog,
2634 u64 bpf_cookie,
2635 struct bpf_prog_array **new_array)
2636 {
2637 int new_prog_cnt, carry_prog_cnt = 0;
2638 struct bpf_prog_array_item *existing, *new;
2639 struct bpf_prog_array *array;
2640 bool found_exclude = false;
2641
2642 /* Figure out how many existing progs we need to carry over to
2643 * the new array.
2644 */
2645 if (old_array) {
2646 existing = old_array->items;
2647 for (; existing->prog; existing++) {
2648 if (existing->prog == exclude_prog) {
2649 found_exclude = true;
2650 continue;
2651 }
2652 if (existing->prog != &dummy_bpf_prog.prog)
2653 carry_prog_cnt++;
2654 if (existing->prog == include_prog)
2655 return -EEXIST;
2656 }
2657 }
2658
2659 if (exclude_prog && !found_exclude)
2660 return -ENOENT;
2661
2662 /* How many progs (not NULL) will be in the new array? */
2663 new_prog_cnt = carry_prog_cnt;
2664 if (include_prog)
2665 new_prog_cnt += 1;
2666
2667 /* Do we have any prog (not NULL) in the new array? */
2668 if (!new_prog_cnt) {
2669 *new_array = NULL;
2670 return 0;
2671 }
2672
2673 /* +1 as the end of prog_array is marked with NULL */
2674 array = bpf_prog_array_alloc(new_prog_cnt + 1, GFP_KERNEL);
2675 if (!array)
2676 return -ENOMEM;
2677 new = array->items;
2678
2679 /* Fill in the new prog array */
2680 if (carry_prog_cnt) {
2681 existing = old_array->items;
2682 for (; existing->prog; existing++) {
2683 if (existing->prog == exclude_prog ||
2684 existing->prog == &dummy_bpf_prog.prog)
2685 continue;
2686
2687 new->prog = existing->prog;
2688 new->bpf_cookie = existing->bpf_cookie;
2689 new++;
2690 }
2691 }
2692 if (include_prog) {
2693 new->prog = include_prog;
2694 new->bpf_cookie = bpf_cookie;
2695 new++;
2696 }
2697 new->prog = NULL;
2698 *new_array = array;
2699 return 0;
2700 }
2701
bpf_prog_array_copy_info(struct bpf_prog_array * array,u32 * prog_ids,u32 request_cnt,u32 * prog_cnt)2702 int bpf_prog_array_copy_info(struct bpf_prog_array *array,
2703 u32 *prog_ids, u32 request_cnt,
2704 u32 *prog_cnt)
2705 {
2706 u32 cnt = 0;
2707
2708 if (array)
2709 cnt = bpf_prog_array_length(array);
2710
2711 *prog_cnt = cnt;
2712
2713 /* return early if user requested only program count or nothing to copy */
2714 if (!request_cnt || !cnt)
2715 return 0;
2716
2717 /* this function is called under trace/bpf_trace.c: bpf_event_mutex */
2718 return bpf_prog_array_copy_core(array, prog_ids, request_cnt) ? -ENOSPC
2719 : 0;
2720 }
2721
__bpf_free_used_maps(struct bpf_prog_aux * aux,struct bpf_map ** used_maps,u32 len)2722 void __bpf_free_used_maps(struct bpf_prog_aux *aux,
2723 struct bpf_map **used_maps, u32 len)
2724 {
2725 struct bpf_map *map;
2726 bool sleepable;
2727 u32 i;
2728
2729 sleepable = aux->prog->sleepable;
2730 for (i = 0; i < len; i++) {
2731 map = used_maps[i];
2732 if (map->ops->map_poke_untrack)
2733 map->ops->map_poke_untrack(map, aux);
2734 if (sleepable)
2735 atomic64_dec(&map->sleepable_refcnt);
2736 bpf_map_put(map);
2737 }
2738 }
2739
bpf_free_used_maps(struct bpf_prog_aux * aux)2740 static void bpf_free_used_maps(struct bpf_prog_aux *aux)
2741 {
2742 __bpf_free_used_maps(aux, aux->used_maps, aux->used_map_cnt);
2743 kfree(aux->used_maps);
2744 }
2745
__bpf_free_used_btfs(struct bpf_prog_aux * aux,struct btf_mod_pair * used_btfs,u32 len)2746 void __bpf_free_used_btfs(struct bpf_prog_aux *aux,
2747 struct btf_mod_pair *used_btfs, u32 len)
2748 {
2749 #ifdef CONFIG_BPF_SYSCALL
2750 struct btf_mod_pair *btf_mod;
2751 u32 i;
2752
2753 for (i = 0; i < len; i++) {
2754 btf_mod = &used_btfs[i];
2755 if (btf_mod->module)
2756 module_put(btf_mod->module);
2757 btf_put(btf_mod->btf);
2758 }
2759 #endif
2760 }
2761
bpf_free_used_btfs(struct bpf_prog_aux * aux)2762 static void bpf_free_used_btfs(struct bpf_prog_aux *aux)
2763 {
2764 __bpf_free_used_btfs(aux, aux->used_btfs, aux->used_btf_cnt);
2765 kfree(aux->used_btfs);
2766 }
2767
bpf_prog_free_deferred(struct work_struct * work)2768 static void bpf_prog_free_deferred(struct work_struct *work)
2769 {
2770 struct bpf_prog_aux *aux;
2771 int i;
2772
2773 aux = container_of(work, struct bpf_prog_aux, work);
2774 #ifdef CONFIG_BPF_SYSCALL
2775 bpf_free_kfunc_btf_tab(aux->kfunc_btf_tab);
2776 #endif
2777 #ifdef CONFIG_CGROUP_BPF
2778 if (aux->cgroup_atype != CGROUP_BPF_ATTACH_TYPE_INVALID)
2779 bpf_cgroup_atype_put(aux->cgroup_atype);
2780 #endif
2781 bpf_free_used_maps(aux);
2782 bpf_free_used_btfs(aux);
2783 if (bpf_prog_is_dev_bound(aux))
2784 bpf_prog_dev_bound_destroy(aux->prog);
2785 #ifdef CONFIG_PERF_EVENTS
2786 if (aux->prog->has_callchain_buf)
2787 put_callchain_buffers();
2788 #endif
2789 if (aux->dst_trampoline)
2790 bpf_trampoline_put(aux->dst_trampoline);
2791 for (i = 0; i < aux->real_func_cnt; i++) {
2792 /* We can just unlink the subprog poke descriptor table as
2793 * it was originally linked to the main program and is also
2794 * released along with it.
2795 */
2796 aux->func[i]->aux->poke_tab = NULL;
2797 bpf_jit_free(aux->func[i]);
2798 }
2799 if (aux->real_func_cnt) {
2800 kfree(aux->func);
2801 bpf_prog_unlock_free(aux->prog);
2802 } else {
2803 bpf_jit_free(aux->prog);
2804 }
2805 }
2806
bpf_prog_free(struct bpf_prog * fp)2807 void bpf_prog_free(struct bpf_prog *fp)
2808 {
2809 struct bpf_prog_aux *aux = fp->aux;
2810
2811 if (aux->dst_prog)
2812 bpf_prog_put(aux->dst_prog);
2813 bpf_token_put(aux->token);
2814 INIT_WORK(&aux->work, bpf_prog_free_deferred);
2815 schedule_work(&aux->work);
2816 }
2817 EXPORT_SYMBOL_GPL(bpf_prog_free);
2818
2819 /* RNG for unprivileged user space with separated state from prandom_u32(). */
2820 static DEFINE_PER_CPU(struct rnd_state, bpf_user_rnd_state);
2821
bpf_user_rnd_init_once(void)2822 void bpf_user_rnd_init_once(void)
2823 {
2824 prandom_init_once(&bpf_user_rnd_state);
2825 }
2826
BPF_CALL_0(bpf_user_rnd_u32)2827 BPF_CALL_0(bpf_user_rnd_u32)
2828 {
2829 /* Should someone ever have the rather unwise idea to use some
2830 * of the registers passed into this function, then note that
2831 * this function is called from native eBPF and classic-to-eBPF
2832 * transformations. Register assignments from both sides are
2833 * different, f.e. classic always sets fn(ctx, A, X) here.
2834 */
2835 struct rnd_state *state;
2836 u32 res;
2837
2838 state = &get_cpu_var(bpf_user_rnd_state);
2839 res = prandom_u32_state(state);
2840 put_cpu_var(bpf_user_rnd_state);
2841
2842 return res;
2843 }
2844
BPF_CALL_0(bpf_get_raw_cpu_id)2845 BPF_CALL_0(bpf_get_raw_cpu_id)
2846 {
2847 return raw_smp_processor_id();
2848 }
2849
2850 /* Weak definitions of helper functions in case we don't have bpf syscall. */
2851 const struct bpf_func_proto bpf_map_lookup_elem_proto __weak;
2852 const struct bpf_func_proto bpf_map_update_elem_proto __weak;
2853 const struct bpf_func_proto bpf_map_delete_elem_proto __weak;
2854 const struct bpf_func_proto bpf_map_push_elem_proto __weak;
2855 const struct bpf_func_proto bpf_map_pop_elem_proto __weak;
2856 const struct bpf_func_proto bpf_map_peek_elem_proto __weak;
2857 const struct bpf_func_proto bpf_map_lookup_percpu_elem_proto __weak;
2858 const struct bpf_func_proto bpf_spin_lock_proto __weak;
2859 const struct bpf_func_proto bpf_spin_unlock_proto __weak;
2860 const struct bpf_func_proto bpf_jiffies64_proto __weak;
2861
2862 const struct bpf_func_proto bpf_get_prandom_u32_proto __weak;
2863 const struct bpf_func_proto bpf_get_smp_processor_id_proto __weak;
2864 const struct bpf_func_proto bpf_get_numa_node_id_proto __weak;
2865 const struct bpf_func_proto bpf_ktime_get_ns_proto __weak;
2866 const struct bpf_func_proto bpf_ktime_get_boot_ns_proto __weak;
2867 const struct bpf_func_proto bpf_ktime_get_coarse_ns_proto __weak;
2868 const struct bpf_func_proto bpf_ktime_get_tai_ns_proto __weak;
2869
2870 const struct bpf_func_proto bpf_get_current_pid_tgid_proto __weak;
2871 const struct bpf_func_proto bpf_get_current_uid_gid_proto __weak;
2872 const struct bpf_func_proto bpf_get_current_comm_proto __weak;
2873 const struct bpf_func_proto bpf_get_current_cgroup_id_proto __weak;
2874 const struct bpf_func_proto bpf_get_current_ancestor_cgroup_id_proto __weak;
2875 const struct bpf_func_proto bpf_get_local_storage_proto __weak;
2876 const struct bpf_func_proto bpf_get_ns_current_pid_tgid_proto __weak;
2877 const struct bpf_func_proto bpf_snprintf_btf_proto __weak;
2878 const struct bpf_func_proto bpf_seq_printf_btf_proto __weak;
2879 const struct bpf_func_proto bpf_set_retval_proto __weak;
2880 const struct bpf_func_proto bpf_get_retval_proto __weak;
2881
bpf_get_trace_printk_proto(void)2882 const struct bpf_func_proto * __weak bpf_get_trace_printk_proto(void)
2883 {
2884 return NULL;
2885 }
2886
bpf_get_trace_vprintk_proto(void)2887 const struct bpf_func_proto * __weak bpf_get_trace_vprintk_proto(void)
2888 {
2889 return NULL;
2890 }
2891
2892 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)2893 bpf_event_output(struct bpf_map *map, u64 flags, void *meta, u64 meta_size,
2894 void *ctx, u64 ctx_size, bpf_ctx_copy_t ctx_copy)
2895 {
2896 return -ENOTSUPP;
2897 }
2898 EXPORT_SYMBOL_GPL(bpf_event_output);
2899
2900 /* Always built-in helper functions. */
2901 const struct bpf_func_proto bpf_tail_call_proto = {
2902 .func = NULL,
2903 .gpl_only = false,
2904 .ret_type = RET_VOID,
2905 .arg1_type = ARG_PTR_TO_CTX,
2906 .arg2_type = ARG_CONST_MAP_PTR,
2907 .arg3_type = ARG_ANYTHING,
2908 };
2909
2910 /* Stub for JITs that only support cBPF. eBPF programs are interpreted.
2911 * It is encouraged to implement bpf_int_jit_compile() instead, so that
2912 * eBPF and implicitly also cBPF can get JITed!
2913 */
bpf_int_jit_compile(struct bpf_prog * prog)2914 struct bpf_prog * __weak bpf_int_jit_compile(struct bpf_prog *prog)
2915 {
2916 return prog;
2917 }
2918
2919 /* Stub for JITs that support eBPF. All cBPF code gets transformed into
2920 * eBPF by the kernel and is later compiled by bpf_int_jit_compile().
2921 */
bpf_jit_compile(struct bpf_prog * prog)2922 void __weak bpf_jit_compile(struct bpf_prog *prog)
2923 {
2924 }
2925
bpf_helper_changes_pkt_data(void * func)2926 bool __weak bpf_helper_changes_pkt_data(void *func)
2927 {
2928 return false;
2929 }
2930
2931 /* Return TRUE if the JIT backend wants verifier to enable sub-register usage
2932 * analysis code and wants explicit zero extension inserted by verifier.
2933 * Otherwise, return FALSE.
2934 *
2935 * The verifier inserts an explicit zero extension after BPF_CMPXCHGs even if
2936 * you don't override this. JITs that don't want these extra insns can detect
2937 * them using insn_is_zext.
2938 */
bpf_jit_needs_zext(void)2939 bool __weak bpf_jit_needs_zext(void)
2940 {
2941 return false;
2942 }
2943
2944 /* Return true if the JIT inlines the call to the helper corresponding to
2945 * the imm.
2946 *
2947 * The verifier will not patch the insn->imm for the call to the helper if
2948 * this returns true.
2949 */
bpf_jit_inlines_helper_call(s32 imm)2950 bool __weak bpf_jit_inlines_helper_call(s32 imm)
2951 {
2952 return false;
2953 }
2954
2955 /* Return TRUE if the JIT backend supports mixing bpf2bpf and tailcalls. */
bpf_jit_supports_subprog_tailcalls(void)2956 bool __weak bpf_jit_supports_subprog_tailcalls(void)
2957 {
2958 return false;
2959 }
2960
bpf_jit_supports_percpu_insn(void)2961 bool __weak bpf_jit_supports_percpu_insn(void)
2962 {
2963 return false;
2964 }
2965
bpf_jit_supports_kfunc_call(void)2966 bool __weak bpf_jit_supports_kfunc_call(void)
2967 {
2968 return false;
2969 }
2970
bpf_jit_supports_far_kfunc_call(void)2971 bool __weak bpf_jit_supports_far_kfunc_call(void)
2972 {
2973 return false;
2974 }
2975
bpf_jit_supports_arena(void)2976 bool __weak bpf_jit_supports_arena(void)
2977 {
2978 return false;
2979 }
2980
bpf_jit_supports_insn(struct bpf_insn * insn,bool in_arena)2981 bool __weak bpf_jit_supports_insn(struct bpf_insn *insn, bool in_arena)
2982 {
2983 return false;
2984 }
2985
bpf_arch_uaddress_limit(void)2986 u64 __weak bpf_arch_uaddress_limit(void)
2987 {
2988 #if defined(CONFIG_64BIT) && defined(CONFIG_ARCH_HAS_NON_OVERLAPPING_ADDRESS_SPACE)
2989 return TASK_SIZE;
2990 #else
2991 return 0;
2992 #endif
2993 }
2994
2995 /* Return TRUE if the JIT backend satisfies the following two conditions:
2996 * 1) JIT backend supports atomic_xchg() on pointer-sized words.
2997 * 2) Under the specific arch, the implementation of xchg() is the same
2998 * as atomic_xchg() on pointer-sized words.
2999 */
bpf_jit_supports_ptr_xchg(void)3000 bool __weak bpf_jit_supports_ptr_xchg(void)
3001 {
3002 return false;
3003 }
3004
3005 /* To execute LD_ABS/LD_IND instructions __bpf_prog_run() may call
3006 * skb_copy_bits(), so provide a weak definition of it for NET-less config.
3007 */
skb_copy_bits(const struct sk_buff * skb,int offset,void * to,int len)3008 int __weak skb_copy_bits(const struct sk_buff *skb, int offset, void *to,
3009 int len)
3010 {
3011 return -EFAULT;
3012 }
3013
bpf_arch_text_poke(void * ip,enum bpf_text_poke_type t,void * addr1,void * addr2)3014 int __weak bpf_arch_text_poke(void *ip, enum bpf_text_poke_type t,
3015 void *addr1, void *addr2)
3016 {
3017 return -ENOTSUPP;
3018 }
3019
bpf_arch_text_copy(void * dst,void * src,size_t len)3020 void * __weak bpf_arch_text_copy(void *dst, void *src, size_t len)
3021 {
3022 return ERR_PTR(-ENOTSUPP);
3023 }
3024
bpf_arch_text_invalidate(void * dst,size_t len)3025 int __weak bpf_arch_text_invalidate(void *dst, size_t len)
3026 {
3027 return -ENOTSUPP;
3028 }
3029
bpf_jit_supports_exceptions(void)3030 bool __weak bpf_jit_supports_exceptions(void)
3031 {
3032 return false;
3033 }
3034
arch_bpf_stack_walk(bool (* consume_fn)(void * cookie,u64 ip,u64 sp,u64 bp),void * cookie)3035 void __weak arch_bpf_stack_walk(bool (*consume_fn)(void *cookie, u64 ip, u64 sp, u64 bp), void *cookie)
3036 {
3037 }
3038
3039 /* for configs without MMU or 32-bit */
3040 __weak const struct bpf_map_ops arena_map_ops;
bpf_arena_get_user_vm_start(struct bpf_arena * arena)3041 __weak u64 bpf_arena_get_user_vm_start(struct bpf_arena *arena)
3042 {
3043 return 0;
3044 }
bpf_arena_get_kern_vm_start(struct bpf_arena * arena)3045 __weak u64 bpf_arena_get_kern_vm_start(struct bpf_arena *arena)
3046 {
3047 return 0;
3048 }
3049
3050 #ifdef CONFIG_BPF_SYSCALL
bpf_global_ma_init(void)3051 static int __init bpf_global_ma_init(void)
3052 {
3053 int ret;
3054
3055 ret = bpf_mem_alloc_init(&bpf_global_ma, 0, false);
3056 bpf_global_ma_set = !ret;
3057 return ret;
3058 }
3059 late_initcall(bpf_global_ma_init);
3060 #endif
3061
3062 DEFINE_STATIC_KEY_FALSE(bpf_stats_enabled_key);
3063 EXPORT_SYMBOL(bpf_stats_enabled_key);
3064
3065 /* All definitions of tracepoints related to BPF. */
3066 #define CREATE_TRACE_POINTS
3067 #include <linux/bpf_trace.h>
3068
3069 EXPORT_TRACEPOINT_SYMBOL_GPL(xdp_exception);
3070 EXPORT_TRACEPOINT_SYMBOL_GPL(xdp_bulk_tx);
3071