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leds: wm831x-status: fix use-after-free on unbind
[linux/fpc-iii.git] / kernel / bpf / core.c
blob9df4cc9a29073ec5e1f9e0f0ec1494d67a2d3a27
1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3 * Linux Socket Filter - Kernel level socket filtering
4 *
5 * Based on the design of the Berkeley Packet Filter. The new
6 * internal format has been designed by PLUMgrid:
7 *
8 * Copyright (c) 2011 - 2014 PLUMgrid, http://plumgrid.com
9 *
10 * Authors:
11 *
12 * Jay Schulist <jschlst@samba.org>
13 * Alexei Starovoitov <ast@plumgrid.com>
14 * Daniel Borkmann <dborkman@redhat.com>
15 *
16 * Andi Kleen - Fix a few bad bugs and races.
17 * Kris Katterjohn - Added many additional checks in bpf_check_classic()
18 */
19
20 #include <uapi/linux/btf.h>
21 #include <linux/filter.h>
22 #include <linux/skbuff.h>
23 #include <linux/vmalloc.h>
24 #include <linux/random.h>
25 #include <linux/moduleloader.h>
26 #include <linux/bpf.h>
27 #include <linux/btf.h>
28 #include <linux/frame.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 <asm/unaligned.h>
36
37 /* Registers */
38 #define BPF_R0 regs[BPF_REG_0]
39 #define BPF_R1 regs[BPF_REG_1]
40 #define BPF_R2 regs[BPF_REG_2]
41 #define BPF_R3 regs[BPF_REG_3]
42 #define BPF_R4 regs[BPF_REG_4]
43 #define BPF_R5 regs[BPF_REG_5]
44 #define BPF_R6 regs[BPF_REG_6]
45 #define BPF_R7 regs[BPF_REG_7]
46 #define BPF_R8 regs[BPF_REG_8]
47 #define BPF_R9 regs[BPF_REG_9]
48 #define BPF_R10 regs[BPF_REG_10]
49
50 /* Named registers */
51 #define DST regs[insn->dst_reg]
52 #define SRC regs[insn->src_reg]
53 #define FP regs[BPF_REG_FP]
54 #define AX regs[BPF_REG_AX]
55 #define ARG1 regs[BPF_REG_ARG1]
56 #define CTX regs[BPF_REG_CTX]
57 #define IMM insn->imm
58
59 /* No hurry in this branch
60 *
61 * Exported for the bpf jit load helper.
62 */
63 void *bpf_internal_load_pointer_neg_helper(const struct sk_buff *skb, int k, unsigned int size)
64 {
65 u8 *ptr = NULL;
66
67 if (k >= SKF_NET_OFF)
68 ptr = skb_network_header(skb) + k - SKF_NET_OFF;
69 else if (k >= SKF_LL_OFF)
70 ptr = skb_mac_header(skb) + k - SKF_LL_OFF;
71
72 if (ptr >= skb->head && ptr + size <= skb_tail_pointer(skb))
73 return ptr;
74
75 return NULL;
76 }
77
78 struct bpf_prog *bpf_prog_alloc_no_stats(unsigned int size, gfp_t gfp_extra_flags)
79 {
80 gfp_t gfp_flags = GFP_KERNEL | __GFP_ZERO | gfp_extra_flags;
81 struct bpf_prog_aux *aux;
82 struct bpf_prog *fp;
83
84 size = round_up(size, PAGE_SIZE);
85 fp = __vmalloc(size, gfp_flags);
86 if (fp == NULL)
87 return NULL;
88
89 aux = kzalloc(sizeof(*aux), GFP_KERNEL | gfp_extra_flags);
90 if (aux == NULL) {
91 vfree(fp);
92 return NULL;
93 }
94
95 fp->pages = size / PAGE_SIZE;
96 fp->aux = aux;
97 fp->aux->prog = fp;
98 fp->jit_requested = ebpf_jit_enabled();
99
100 INIT_LIST_HEAD_RCU(&fp->aux->ksym.lnode);
101
102 return fp;
103 }
104
105 struct bpf_prog *bpf_prog_alloc(unsigned int size, gfp_t gfp_extra_flags)
106 {
107 gfp_t gfp_flags = GFP_KERNEL | __GFP_ZERO | gfp_extra_flags;
108 struct bpf_prog *prog;
109 int cpu;
110
111 prog = bpf_prog_alloc_no_stats(size, gfp_extra_flags);
112 if (!prog)
113 return NULL;
114
115 prog->aux->stats = alloc_percpu_gfp(struct bpf_prog_stats, gfp_flags);
116 if (!prog->aux->stats) {
117 kfree(prog->aux);
118 vfree(prog);
119 return NULL;
120 }
121
122 for_each_possible_cpu(cpu) {
123 struct bpf_prog_stats *pstats;
124
125 pstats = per_cpu_ptr(prog->aux->stats, cpu);
126 u64_stats_init(&pstats->syncp);
127 }
128 return prog;
129 }
130 EXPORT_SYMBOL_GPL(bpf_prog_alloc);
131
132 int bpf_prog_alloc_jited_linfo(struct bpf_prog *prog)
133 {
134 if (!prog->aux->nr_linfo || !prog->jit_requested)
135 return 0;
136
137 prog->aux->jited_linfo = kcalloc(prog->aux->nr_linfo,
138 sizeof(*prog->aux->jited_linfo),
139 GFP_KERNEL | __GFP_NOWARN);
140 if (!prog->aux->jited_linfo)
141 return -ENOMEM;
142
143 return 0;
144 }
145
146 void bpf_prog_free_jited_linfo(struct bpf_prog *prog)
147 {
148 kfree(prog->aux->jited_linfo);
149 prog->aux->jited_linfo = NULL;
150 }
151
152 void bpf_prog_free_unused_jited_linfo(struct bpf_prog *prog)
153 {
154 if (prog->aux->jited_linfo && !prog->aux->jited_linfo[0])
155 bpf_prog_free_jited_linfo(prog);
156 }
157
158 /* The jit engine is responsible to provide an array
159 * for insn_off to the jited_off mapping (insn_to_jit_off).
160 *
161 * The idx to this array is the insn_off. Hence, the insn_off
162 * here is relative to the prog itself instead of the main prog.
163 * This array has one entry for each xlated bpf insn.
164 *
165 * jited_off is the byte off to the last byte of the jited insn.
166 *
167 * Hence, with
168 * insn_start:
169 * The first bpf insn off of the prog. The insn off
170 * here is relative to the main prog.
171 * e.g. if prog is a subprog, insn_start > 0
172 * linfo_idx:
173 * The prog's idx to prog->aux->linfo and jited_linfo
174 *
175 * jited_linfo[linfo_idx] = prog->bpf_func
176 *
177 * For i > linfo_idx,
178 *
179 * jited_linfo[i] = prog->bpf_func +
180 * insn_to_jit_off[linfo[i].insn_off - insn_start - 1]
181 */
182 void bpf_prog_fill_jited_linfo(struct bpf_prog *prog,
183 const u32 *insn_to_jit_off)
184 {
185 u32 linfo_idx, insn_start, insn_end, nr_linfo, i;
186 const struct bpf_line_info *linfo;
187 void **jited_linfo;
188
189 if (!prog->aux->jited_linfo)
190 /* Userspace did not provide linfo */
191 return;
192
193 linfo_idx = prog->aux->linfo_idx;
194 linfo = &prog->aux->linfo[linfo_idx];
195 insn_start = linfo[0].insn_off;
196 insn_end = insn_start + prog->len;
197
198 jited_linfo = &prog->aux->jited_linfo[linfo_idx];
199 jited_linfo[0] = prog->bpf_func;
200
201 nr_linfo = prog->aux->nr_linfo - linfo_idx;
202
203 for (i = 1; i < nr_linfo && linfo[i].insn_off < insn_end; i++)
204 /* The verifier ensures that linfo[i].insn_off is
205 * strictly increasing
206 */
207 jited_linfo[i] = prog->bpf_func +
208 insn_to_jit_off[linfo[i].insn_off - insn_start - 1];
209 }
210
211 void bpf_prog_free_linfo(struct bpf_prog *prog)
212 {
213 bpf_prog_free_jited_linfo(prog);
214 kvfree(prog->aux->linfo);
215 }
216
217 struct bpf_prog *bpf_prog_realloc(struct bpf_prog *fp_old, unsigned int size,
218 gfp_t gfp_extra_flags)
219 {
220 gfp_t gfp_flags = GFP_KERNEL | __GFP_ZERO | gfp_extra_flags;
221 struct bpf_prog *fp;
222 u32 pages, delta;
223 int ret;
224
225 size = round_up(size, PAGE_SIZE);
226 pages = size / PAGE_SIZE;
227 if (pages <= fp_old->pages)
228 return fp_old;
229
230 delta = pages - fp_old->pages;
231 ret = __bpf_prog_charge(fp_old->aux->user, delta);
232 if (ret)
233 return NULL;
234
235 fp = __vmalloc(size, gfp_flags);
236 if (fp == NULL) {
237 __bpf_prog_uncharge(fp_old->aux->user, delta);
238 } else {
239 memcpy(fp, fp_old, fp_old->pages * PAGE_SIZE);
240 fp->pages = pages;
241 fp->aux->prog = fp;
242
243 /* We keep fp->aux from fp_old around in the new
244 * reallocated structure.
245 */
246 fp_old->aux = NULL;
247 __bpf_prog_free(fp_old);
248 }
249
250 return fp;
251 }
252
253 void __bpf_prog_free(struct bpf_prog *fp)
254 {
255 if (fp->aux) {
256 free_percpu(fp->aux->stats);
257 kfree(fp->aux->poke_tab);
258 kfree(fp->aux);
259 }
260 vfree(fp);
261 }
262
263 int bpf_prog_calc_tag(struct bpf_prog *fp)
264 {
265 const u32 bits_offset = SHA1_BLOCK_SIZE - sizeof(__be64);
266 u32 raw_size = bpf_prog_tag_scratch_size(fp);
267 u32 digest[SHA1_DIGEST_WORDS];
268 u32 ws[SHA1_WORKSPACE_WORDS];
269 u32 i, bsize, psize, blocks;
270 struct bpf_insn *dst;
271 bool was_ld_map;
272 u8 *raw, *todo;
273 __be32 *result;
274 __be64 *bits;
275
276 raw = vmalloc(raw_size);
277 if (!raw)
278 return -ENOMEM;
279
280 sha1_init(digest);
281 memset(ws, 0, sizeof(ws));
282
283 /* We need to take out the map fd for the digest calculation
284 * since they are unstable from user space side.
285 */
286 dst = (void *)raw;
287 for (i = 0, was_ld_map = false; i < fp->len; i++) {
288 dst[i] = fp->insnsi[i];
289 if (!was_ld_map &&
290 dst[i].code == (BPF_LD | BPF_IMM | BPF_DW) &&
291 (dst[i].src_reg == BPF_PSEUDO_MAP_FD ||
292 dst[i].src_reg == BPF_PSEUDO_MAP_VALUE)) {
293 was_ld_map = true;
294 dst[i].imm = 0;
295 } else if (was_ld_map &&
296 dst[i].code == 0 &&
297 dst[i].dst_reg == 0 &&
298 dst[i].src_reg == 0 &&
299 dst[i].off == 0) {
300 was_ld_map = false;
301 dst[i].imm = 0;
302 } else {
303 was_ld_map = false;
304 }
305 }
306
307 psize = bpf_prog_insn_size(fp);
308 memset(&raw[psize], 0, raw_size - psize);
309 raw[psize++] = 0x80;
310
311 bsize = round_up(psize, SHA1_BLOCK_SIZE);
312 blocks = bsize / SHA1_BLOCK_SIZE;
313 todo = raw;
314 if (bsize - psize >= sizeof(__be64)) {
315 bits = (__be64 *)(todo + bsize - sizeof(__be64));
316 } else {
317 bits = (__be64 *)(todo + bsize + bits_offset);
318 blocks++;
319 }
320 *bits = cpu_to_be64((psize - 1) << 3);
321
322 while (blocks--) {
323 sha1_transform(digest, todo, ws);
324 todo += SHA1_BLOCK_SIZE;
325 }
326
327 result = (__force __be32 *)digest;
328 for (i = 0; i < SHA1_DIGEST_WORDS; i++)
329 result[i] = cpu_to_be32(digest[i]);
330 memcpy(fp->tag, result, sizeof(fp->tag));
331
332 vfree(raw);
333 return 0;
334 }
335
336 static int bpf_adj_delta_to_imm(struct bpf_insn *insn, u32 pos, s32 end_old,
337 s32 end_new, s32 curr, const bool probe_pass)
338 {
339 const s64 imm_min = S32_MIN, imm_max = S32_MAX;
340 s32 delta = end_new - end_old;
341 s64 imm = insn->imm;
342
343 if (curr < pos && curr + imm + 1 >= end_old)
344 imm += delta;
345 else if (curr >= end_new && curr + imm + 1 < end_new)
346 imm -= delta;
347 if (imm < imm_min || imm > imm_max)
348 return -ERANGE;
349 if (!probe_pass)
350 insn->imm = imm;
351 return 0;
352 }
353
354 static int bpf_adj_delta_to_off(struct bpf_insn *insn, u32 pos, s32 end_old,
355 s32 end_new, s32 curr, const bool probe_pass)
356 {
357 const s32 off_min = S16_MIN, off_max = S16_MAX;
358 s32 delta = end_new - end_old;
359 s32 off = insn->off;
360
361 if (curr < pos && curr + off + 1 >= end_old)
362 off += delta;
363 else if (curr >= end_new && curr + off + 1 < end_new)
364 off -= delta;
365 if (off < off_min || off > off_max)
366 return -ERANGE;
367 if (!probe_pass)
368 insn->off = off;
369 return 0;
370 }
371
372 static int bpf_adj_branches(struct bpf_prog *prog, u32 pos, s32 end_old,
373 s32 end_new, const bool probe_pass)
374 {
375 u32 i, insn_cnt = prog->len + (probe_pass ? end_new - end_old : 0);
376 struct bpf_insn *insn = prog->insnsi;
377 int ret = 0;
378
379 for (i = 0; i < insn_cnt; i++, insn++) {
380 u8 code;
381
382 /* In the probing pass we still operate on the original,
383 * unpatched image in order to check overflows before we
384 * do any other adjustments. Therefore skip the patchlet.
385 */
386 if (probe_pass && i == pos) {
387 i = end_new;
388 insn = prog->insnsi + end_old;
389 }
390 code = insn->code;
391 if ((BPF_CLASS(code) != BPF_JMP &&
392 BPF_CLASS(code) != BPF_JMP32) ||
393 BPF_OP(code) == BPF_EXIT)
394 continue;
395 /* Adjust offset of jmps if we cross patch boundaries. */
396 if (BPF_OP(code) == BPF_CALL) {
397 if (insn->src_reg != BPF_PSEUDO_CALL)
398 continue;
399 ret = bpf_adj_delta_to_imm(insn, pos, end_old,
400 end_new, i, probe_pass);
401 } else {
402 ret = bpf_adj_delta_to_off(insn, pos, end_old,
403 end_new, i, probe_pass);
404 }
405 if (ret)
406 break;
407 }
408
409 return ret;
410 }
411
412 static void bpf_adj_linfo(struct bpf_prog *prog, u32 off, u32 delta)
413 {
414 struct bpf_line_info *linfo;
415 u32 i, nr_linfo;
416
417 nr_linfo = prog->aux->nr_linfo;
418 if (!nr_linfo || !delta)
419 return;
420
421 linfo = prog->aux->linfo;
422
423 for (i = 0; i < nr_linfo; i++)
424 if (off < linfo[i].insn_off)
425 break;
426
427 /* Push all off < linfo[i].insn_off by delta */
428 for (; i < nr_linfo; i++)
429 linfo[i].insn_off += delta;
430 }
431
432 struct bpf_prog *bpf_patch_insn_single(struct bpf_prog *prog, u32 off,
433 const struct bpf_insn *patch, u32 len)
434 {
435 u32 insn_adj_cnt, insn_rest, insn_delta = len - 1;
436 const u32 cnt_max = S16_MAX;
437 struct bpf_prog *prog_adj;
438 int err;
439
440 /* Since our patchlet doesn't expand the image, we're done. */
441 if (insn_delta == 0) {
442 memcpy(prog->insnsi + off, patch, sizeof(*patch));
443 return prog;
444 }
445
446 insn_adj_cnt = prog->len + insn_delta;
447
448 /* Reject anything that would potentially let the insn->off
449 * target overflow when we have excessive program expansions.
450 * We need to probe here before we do any reallocation where
451 * we afterwards may not fail anymore.
452 */
453 if (insn_adj_cnt > cnt_max &&
454 (err = bpf_adj_branches(prog, off, off + 1, off + len, true)))
455 return ERR_PTR(err);
456
457 /* Several new instructions need to be inserted. Make room
458 * for them. Likely, there's no need for a new allocation as
459 * last page could have large enough tailroom.
460 */
461 prog_adj = bpf_prog_realloc(prog, bpf_prog_size(insn_adj_cnt),
462 GFP_USER);
463 if (!prog_adj)
464 return ERR_PTR(-ENOMEM);
465
466 prog_adj->len = insn_adj_cnt;
467
468 /* Patching happens in 3 steps:
469 *
470 * 1) Move over tail of insnsi from next instruction onwards,
471 * so we can patch the single target insn with one or more
472 * new ones (patching is always from 1 to n insns, n > 0).
473 * 2) Inject new instructions at the target location.
474 * 3) Adjust branch offsets if necessary.
475 */
476 insn_rest = insn_adj_cnt - off - len;
477
478 memmove(prog_adj->insnsi + off + len, prog_adj->insnsi + off + 1,
479 sizeof(*patch) * insn_rest);
480 memcpy(prog_adj->insnsi + off, patch, sizeof(*patch) * len);
481
482 /* We are guaranteed to not fail at this point, otherwise
483 * the ship has sailed to reverse to the original state. An
484 * overflow cannot happen at this point.
485 */
486 BUG_ON(bpf_adj_branches(prog_adj, off, off + 1, off + len, false));
487
488 bpf_adj_linfo(prog_adj, off, insn_delta);
489
490 return prog_adj;
491 }
492
493 int bpf_remove_insns(struct bpf_prog *prog, u32 off, u32 cnt)
494 {
495 /* Branch offsets can't overflow when program is shrinking, no need
496 * to call bpf_adj_branches(..., true) here
497 */
498 memmove(prog->insnsi + off, prog->insnsi + off + cnt,
499 sizeof(struct bpf_insn) * (prog->len - off - cnt));
500 prog->len -= cnt;
501
502 return WARN_ON_ONCE(bpf_adj_branches(prog, off, off + cnt, off, false));
503 }
504
505 static void bpf_prog_kallsyms_del_subprogs(struct bpf_prog *fp)
506 {
507 int i;
508
509 for (i = 0; i < fp->aux->func_cnt; i++)
510 bpf_prog_kallsyms_del(fp->aux->func[i]);
511 }
512
513 void bpf_prog_kallsyms_del_all(struct bpf_prog *fp)
514 {
515 bpf_prog_kallsyms_del_subprogs(fp);
516 bpf_prog_kallsyms_del(fp);
517 }
518
519 #ifdef CONFIG_BPF_JIT
520 /* All BPF JIT sysctl knobs here. */
521 int bpf_jit_enable __read_mostly = IS_BUILTIN(CONFIG_BPF_JIT_DEFAULT_ON);
522 int bpf_jit_kallsyms __read_mostly = IS_BUILTIN(CONFIG_BPF_JIT_DEFAULT_ON);
523 int bpf_jit_harden __read_mostly;
524 long bpf_jit_limit __read_mostly;
525
526 static void
527 bpf_prog_ksym_set_addr(struct bpf_prog *prog)
528 {
529 const struct bpf_binary_header *hdr = bpf_jit_binary_hdr(prog);
530 unsigned long addr = (unsigned long)hdr;
531
532 WARN_ON_ONCE(!bpf_prog_ebpf_jited(prog));
533
534 prog->aux->ksym.start = (unsigned long) prog->bpf_func;
535 prog->aux->ksym.end = addr + hdr->pages * PAGE_SIZE;
536 }
537
538 static void
539 bpf_prog_ksym_set_name(struct bpf_prog *prog)
540 {
541 char *sym = prog->aux->ksym.name;
542 const char *end = sym + KSYM_NAME_LEN;
543 const struct btf_type *type;
544 const char *func_name;
545
546 BUILD_BUG_ON(sizeof("bpf_prog_") +
547 sizeof(prog->tag) * 2 +
548 /* name has been null terminated.
549 * We should need +1 for the '_' preceding
550 * the name. However, the null character
551 * is double counted between the name and the
552 * sizeof("bpf_prog_") above, so we omit
553 * the +1 here.
554 */
555 sizeof(prog->aux->name) > KSYM_NAME_LEN);
556
557 sym += snprintf(sym, KSYM_NAME_LEN, "bpf_prog_");
558 sym = bin2hex(sym, prog->tag, sizeof(prog->tag));
559
560 /* prog->aux->name will be ignored if full btf name is available */
561 if (prog->aux->func_info_cnt) {
562 type = btf_type_by_id(prog->aux->btf,
563 prog->aux->func_info[prog->aux->func_idx].type_id);
564 func_name = btf_name_by_offset(prog->aux->btf, type->name_off);
565 snprintf(sym, (size_t)(end - sym), "_%s", func_name);
566 return;
567 }
568
569 if (prog->aux->name[0])
570 snprintf(sym, (size_t)(end - sym), "_%s", prog->aux->name);
571 else
572 *sym = 0;
573 }
574
575 static unsigned long bpf_get_ksym_start(struct latch_tree_node *n)
576 {
577 return container_of(n, struct bpf_ksym, tnode)->start;
578 }
579
580 static __always_inline bool bpf_tree_less(struct latch_tree_node *a,
581 struct latch_tree_node *b)
582 {
583 return bpf_get_ksym_start(a) < bpf_get_ksym_start(b);
584 }
585
586 static __always_inline int bpf_tree_comp(void *key, struct latch_tree_node *n)
587 {
588 unsigned long val = (unsigned long)key;
589 const struct bpf_ksym *ksym;
590
591 ksym = container_of(n, struct bpf_ksym, tnode);
592
593 if (val < ksym->start)
594 return -1;
595 if (val >= ksym->end)
596 return 1;
597
598 return 0;
599 }
600
601 static const struct latch_tree_ops bpf_tree_ops = {
602 .less = bpf_tree_less,
603 .comp = bpf_tree_comp,
604 };
605
606 static DEFINE_SPINLOCK(bpf_lock);
607 static LIST_HEAD(bpf_kallsyms);
608 static struct latch_tree_root bpf_tree __cacheline_aligned;
609
610 void bpf_ksym_add(struct bpf_ksym *ksym)
611 {
612 spin_lock_bh(&bpf_lock);
613 WARN_ON_ONCE(!list_empty(&ksym->lnode));
614 list_add_tail_rcu(&ksym->lnode, &bpf_kallsyms);
615 latch_tree_insert(&ksym->tnode, &bpf_tree, &bpf_tree_ops);
616 spin_unlock_bh(&bpf_lock);
617 }
618
619 static void __bpf_ksym_del(struct bpf_ksym *ksym)
620 {
621 if (list_empty(&ksym->lnode))
622 return;
623
624 latch_tree_erase(&ksym->tnode, &bpf_tree, &bpf_tree_ops);
625 list_del_rcu(&ksym->lnode);
626 }
627
628 void bpf_ksym_del(struct bpf_ksym *ksym)
629 {
630 spin_lock_bh(&bpf_lock);
631 __bpf_ksym_del(ksym);
632 spin_unlock_bh(&bpf_lock);
633 }
634
635 static bool bpf_prog_kallsyms_candidate(const struct bpf_prog *fp)
636 {
637 return fp->jited && !bpf_prog_was_classic(fp);
638 }
639
640 static bool bpf_prog_kallsyms_verify_off(const struct bpf_prog *fp)
641 {
642 return list_empty(&fp->aux->ksym.lnode) ||
643 fp->aux->ksym.lnode.prev == LIST_POISON2;
644 }
645
646 void bpf_prog_kallsyms_add(struct bpf_prog *fp)
647 {
648 if (!bpf_prog_kallsyms_candidate(fp) ||
649 !bpf_capable())
650 return;
651
652 bpf_prog_ksym_set_addr(fp);
653 bpf_prog_ksym_set_name(fp);
654 fp->aux->ksym.prog = true;
655
656 bpf_ksym_add(&fp->aux->ksym);
657 }
658
659 void bpf_prog_kallsyms_del(struct bpf_prog *fp)
660 {
661 if (!bpf_prog_kallsyms_candidate(fp))
662 return;
663
664 bpf_ksym_del(&fp->aux->ksym);
665 }
666
667 static struct bpf_ksym *bpf_ksym_find(unsigned long addr)
668 {
669 struct latch_tree_node *n;
670
671 n = latch_tree_find((void *)addr, &bpf_tree, &bpf_tree_ops);
672 return n ? container_of(n, struct bpf_ksym, tnode) : NULL;
673 }
674
675 const char *__bpf_address_lookup(unsigned long addr, unsigned long *size,
676 unsigned long *off, char *sym)
677 {
678 struct bpf_ksym *ksym;
679 char *ret = NULL;
680
681 rcu_read_lock();
682 ksym = bpf_ksym_find(addr);
683 if (ksym) {
684 unsigned long symbol_start = ksym->start;
685 unsigned long symbol_end = ksym->end;
686
687 strncpy(sym, ksym->name, KSYM_NAME_LEN);
688
689 ret = sym;
690 if (size)
691 *size = symbol_end - symbol_start;
692 if (off)
693 *off = addr - symbol_start;
694 }
695 rcu_read_unlock();
696
697 return ret;
698 }
699
700 bool is_bpf_text_address(unsigned long addr)
701 {
702 bool ret;
703
704 rcu_read_lock();
705 ret = bpf_ksym_find(addr) != NULL;
706 rcu_read_unlock();
707
708 return ret;
709 }
710
711 static struct bpf_prog *bpf_prog_ksym_find(unsigned long addr)
712 {
713 struct bpf_ksym *ksym = bpf_ksym_find(addr);
714
715 return ksym && ksym->prog ?
716 container_of(ksym, struct bpf_prog_aux, ksym)->prog :
717 NULL;
718 }
719
720 const struct exception_table_entry *search_bpf_extables(unsigned long addr)
721 {
722 const struct exception_table_entry *e = NULL;
723 struct bpf_prog *prog;
724
725 rcu_read_lock();
726 prog = bpf_prog_ksym_find(addr);
727 if (!prog)
728 goto out;
729 if (!prog->aux->num_exentries)
730 goto out;
731
732 e = search_extable(prog->aux->extable, prog->aux->num_exentries, addr);
733 out:
734 rcu_read_unlock();
735 return e;
736 }
737
738 int bpf_get_kallsym(unsigned int symnum, unsigned long *value, char *type,
739 char *sym)
740 {
741 struct bpf_ksym *ksym;
742 unsigned int it = 0;
743 int ret = -ERANGE;
744
745 if (!bpf_jit_kallsyms_enabled())
746 return ret;
747
748 rcu_read_lock();
749 list_for_each_entry_rcu(ksym, &bpf_kallsyms, lnode) {
750 if (it++ != symnum)
751 continue;
752
753 strncpy(sym, ksym->name, KSYM_NAME_LEN);
754
755 *value = ksym->start;
756 *type = BPF_SYM_ELF_TYPE;
757
758 ret = 0;
759 break;
760 }
761 rcu_read_unlock();
762
763 return ret;
764 }
765
766 int bpf_jit_add_poke_descriptor(struct bpf_prog *prog,
767 struct bpf_jit_poke_descriptor *poke)
768 {
769 struct bpf_jit_poke_descriptor *tab = prog->aux->poke_tab;
770 static const u32 poke_tab_max = 1024;
771 u32 slot = prog->aux->size_poke_tab;
772 u32 size = slot + 1;
773
774 if (size > poke_tab_max)
775 return -ENOSPC;
776 if (poke->ip || poke->ip_stable || poke->adj_off)
777 return -EINVAL;
778
779 switch (poke->reason) {
780 case BPF_POKE_REASON_TAIL_CALL:
781 if (!poke->tail_call.map)
782 return -EINVAL;
783 break;
784 default:
785 return -EINVAL;
786 }
787
788 tab = krealloc(tab, size * sizeof(*poke), GFP_KERNEL);
789 if (!tab)
790 return -ENOMEM;
791
792 memcpy(&tab[slot], poke, sizeof(*poke));
793 prog->aux->size_poke_tab = size;
794 prog->aux->poke_tab = tab;
795
796 return slot;
797 }
798
799 static atomic_long_t bpf_jit_current;
800
801 /* Can be overridden by an arch's JIT compiler if it has a custom,
802 * dedicated BPF backend memory area, or if neither of the two
803 * below apply.
804 */
805 u64 __weak bpf_jit_alloc_exec_limit(void)
806 {
807 #if defined(MODULES_VADDR)
808 return MODULES_END - MODULES_VADDR;
809 #else
810 return VMALLOC_END - VMALLOC_START;
811 #endif
812 }
813
814 static int __init bpf_jit_charge_init(void)
815 {
816 /* Only used as heuristic here to derive limit. */
817 bpf_jit_limit = min_t(u64, round_up(bpf_jit_alloc_exec_limit() >> 2,
818 PAGE_SIZE), LONG_MAX);
819 return 0;
820 }
821 pure_initcall(bpf_jit_charge_init);
822
823 static int bpf_jit_charge_modmem(u32 pages)
824 {
825 if (atomic_long_add_return(pages, &bpf_jit_current) >
826 (bpf_jit_limit >> PAGE_SHIFT)) {
827 if (!capable(CAP_SYS_ADMIN)) {
828 atomic_long_sub(pages, &bpf_jit_current);
829 return -EPERM;
830 }
831 }
832
833 return 0;
834 }
835
836 static void bpf_jit_uncharge_modmem(u32 pages)
837 {
838 atomic_long_sub(pages, &bpf_jit_current);
839 }
840
841 void *__weak bpf_jit_alloc_exec(unsigned long size)
842 {
843 return module_alloc(size);
844 }
845
846 void __weak bpf_jit_free_exec(void *addr)
847 {
848 module_memfree(addr);
849 }
850
851 struct bpf_binary_header *
852 bpf_jit_binary_alloc(unsigned int proglen, u8 **image_ptr,
853 unsigned int alignment,
854 bpf_jit_fill_hole_t bpf_fill_ill_insns)
855 {
856 struct bpf_binary_header *hdr;
857 u32 size, hole, start, pages;
858
859 WARN_ON_ONCE(!is_power_of_2(alignment) ||
860 alignment > BPF_IMAGE_ALIGNMENT);
861
862 /* Most of BPF filters are really small, but if some of them
863 * fill a page, allow at least 128 extra bytes to insert a
864 * random section of illegal instructions.
865 */
866 size = round_up(proglen + sizeof(*hdr) + 128, PAGE_SIZE);
867 pages = size / PAGE_SIZE;
868
869 if (bpf_jit_charge_modmem(pages))
870 return NULL;
871 hdr = bpf_jit_alloc_exec(size);
872 if (!hdr) {
873 bpf_jit_uncharge_modmem(pages);
874 return NULL;
875 }
876
877 /* Fill space with illegal/arch-dep instructions. */
878 bpf_fill_ill_insns(hdr, size);
879
880 hdr->pages = pages;
881 hole = min_t(unsigned int, size - (proglen + sizeof(*hdr)),
882 PAGE_SIZE - sizeof(*hdr));
883 start = (get_random_int() % hole) & ~(alignment - 1);
884
885 /* Leave a random number of instructions before BPF code. */
886 *image_ptr = &hdr->image[start];
887
888 return hdr;
889 }
890
891 void bpf_jit_binary_free(struct bpf_binary_header *hdr)
892 {
893 u32 pages = hdr->pages;
894
895 bpf_jit_free_exec(hdr);
896 bpf_jit_uncharge_modmem(pages);
897 }
898
899 /* This symbol is only overridden by archs that have different
900 * requirements than the usual eBPF JITs, f.e. when they only
901 * implement cBPF JIT, do not set images read-only, etc.
902 */
903 void __weak bpf_jit_free(struct bpf_prog *fp)
904 {
905 if (fp->jited) {
906 struct bpf_binary_header *hdr = bpf_jit_binary_hdr(fp);
907
908 bpf_jit_binary_free(hdr);
909
910 WARN_ON_ONCE(!bpf_prog_kallsyms_verify_off(fp));
911 }
912
913 bpf_prog_unlock_free(fp);
914 }
915
916 int bpf_jit_get_func_addr(const struct bpf_prog *prog,
917 const struct bpf_insn *insn, bool extra_pass,
918 u64 *func_addr, bool *func_addr_fixed)
919 {
920 s16 off = insn->off;
921 s32 imm = insn->imm;
922 u8 *addr;
923
924 *func_addr_fixed = insn->src_reg != BPF_PSEUDO_CALL;
925 if (!*func_addr_fixed) {
926 /* Place-holder address till the last pass has collected
927 * all addresses for JITed subprograms in which case we
928 * can pick them up from prog->aux.
929 */
930 if (!extra_pass)
931 addr = NULL;
932 else if (prog->aux->func &&
933 off >= 0 && off < prog->aux->func_cnt)
934 addr = (u8 *)prog->aux->func[off]->bpf_func;
935 else
936 return -EINVAL;
937 } else {
938 /* Address of a BPF helper call. Since part of the core
939 * kernel, it's always at a fixed location. __bpf_call_base
940 * and the helper with imm relative to it are both in core
941 * kernel.
942 */
943 addr = (u8 *)__bpf_call_base + imm;
944 }
945
946 *func_addr = (unsigned long)addr;
947 return 0;
948 }
949
950 static int bpf_jit_blind_insn(const struct bpf_insn *from,
951 const struct bpf_insn *aux,
952 struct bpf_insn *to_buff,
953 bool emit_zext)
954 {
955 struct bpf_insn *to = to_buff;
956 u32 imm_rnd = get_random_int();
957 s16 off;
958
959 BUILD_BUG_ON(BPF_REG_AX + 1 != MAX_BPF_JIT_REG);
960 BUILD_BUG_ON(MAX_BPF_REG + 1 != MAX_BPF_JIT_REG);
961
962 /* Constraints on AX register:
963 *
964 * AX register is inaccessible from user space. It is mapped in
965 * all JITs, and used here for constant blinding rewrites. It is
966 * typically "stateless" meaning its contents are only valid within
967 * the executed instruction, but not across several instructions.
968 * There are a few exceptions however which are further detailed
969 * below.
970 *
971 * Constant blinding is only used by JITs, not in the interpreter.
972 * The interpreter uses AX in some occasions as a local temporary
973 * register e.g. in DIV or MOD instructions.
974 *
975 * In restricted circumstances, the verifier can also use the AX
976 * register for rewrites as long as they do not interfere with
977 * the above cases!
978 */
979 if (from->dst_reg == BPF_REG_AX || from->src_reg == BPF_REG_AX)
980 goto out;
981
982 if (from->imm == 0 &&
983 (from->code == (BPF_ALU | BPF_MOV | BPF_K) ||
984 from->code == (BPF_ALU64 | BPF_MOV | BPF_K))) {
985 *to++ = BPF_ALU64_REG(BPF_XOR, from->dst_reg, from->dst_reg);
986 goto out;
987 }
988
989 switch (from->code) {
990 case BPF_ALU | BPF_ADD | BPF_K:
991 case BPF_ALU | BPF_SUB | BPF_K:
992 case BPF_ALU | BPF_AND | BPF_K:
993 case BPF_ALU | BPF_OR | BPF_K:
994 case BPF_ALU | BPF_XOR | BPF_K:
995 case BPF_ALU | BPF_MUL | BPF_K:
996 case BPF_ALU | BPF_MOV | BPF_K:
997 case BPF_ALU | BPF_DIV | BPF_K:
998 case BPF_ALU | BPF_MOD | BPF_K:
999 *to++ = BPF_ALU32_IMM(BPF_MOV, BPF_REG_AX, imm_rnd ^ from->imm);
1000 *to++ = BPF_ALU32_IMM(BPF_XOR, BPF_REG_AX, imm_rnd);
1001 *to++ = BPF_ALU32_REG(from->code, from->dst_reg, BPF_REG_AX);
1002 break;
1003
1004 case BPF_ALU64 | BPF_ADD | BPF_K:
1005 case BPF_ALU64 | BPF_SUB | BPF_K:
1006 case BPF_ALU64 | BPF_AND | BPF_K:
1007 case BPF_ALU64 | BPF_OR | BPF_K:
1008 case BPF_ALU64 | BPF_XOR | BPF_K:
1009 case BPF_ALU64 | BPF_MUL | BPF_K:
1010 case BPF_ALU64 | BPF_MOV | BPF_K:
1011 case BPF_ALU64 | BPF_DIV | BPF_K:
1012 case BPF_ALU64 | BPF_MOD | BPF_K:
1013 *to++ = BPF_ALU64_IMM(BPF_MOV, BPF_REG_AX, imm_rnd ^ from->imm);
1014 *to++ = BPF_ALU64_IMM(BPF_XOR, BPF_REG_AX, imm_rnd);
1015 *to++ = BPF_ALU64_REG(from->code, from->dst_reg, BPF_REG_AX);
1016 break;
1017
1018 case BPF_JMP | BPF_JEQ | BPF_K:
1019 case BPF_JMP | BPF_JNE | BPF_K:
1020 case BPF_JMP | BPF_JGT | BPF_K:
1021 case BPF_JMP | BPF_JLT | BPF_K:
1022 case BPF_JMP | BPF_JGE | BPF_K:
1023 case BPF_JMP | BPF_JLE | BPF_K:
1024 case BPF_JMP | BPF_JSGT | BPF_K:
1025 case BPF_JMP | BPF_JSLT | BPF_K:
1026 case BPF_JMP | BPF_JSGE | BPF_K:
1027 case BPF_JMP | BPF_JSLE | BPF_K:
1028 case BPF_JMP | BPF_JSET | BPF_K:
1029 /* Accommodate for extra offset in case of a backjump. */
1030 off = from->off;
1031 if (off < 0)
1032 off -= 2;
1033 *to++ = BPF_ALU64_IMM(BPF_MOV, BPF_REG_AX, imm_rnd ^ from->imm);
1034 *to++ = BPF_ALU64_IMM(BPF_XOR, BPF_REG_AX, imm_rnd);
1035 *to++ = BPF_JMP_REG(from->code, from->dst_reg, BPF_REG_AX, off);
1036 break;
1037
1038 case BPF_JMP32 | BPF_JEQ | BPF_K:
1039 case BPF_JMP32 | BPF_JNE | BPF_K:
1040 case BPF_JMP32 | BPF_JGT | BPF_K:
1041 case BPF_JMP32 | BPF_JLT | BPF_K:
1042 case BPF_JMP32 | BPF_JGE | BPF_K:
1043 case BPF_JMP32 | BPF_JLE | BPF_K:
1044 case BPF_JMP32 | BPF_JSGT | BPF_K:
1045 case BPF_JMP32 | BPF_JSLT | BPF_K:
1046 case BPF_JMP32 | BPF_JSGE | BPF_K:
1047 case BPF_JMP32 | BPF_JSLE | BPF_K:
1048 case BPF_JMP32 | BPF_JSET | BPF_K:
1049 /* Accommodate for extra offset in case of a backjump. */
1050 off = from->off;
1051 if (off < 0)
1052 off -= 2;
1053 *to++ = BPF_ALU32_IMM(BPF_MOV, BPF_REG_AX, imm_rnd ^ from->imm);
1054 *to++ = BPF_ALU32_IMM(BPF_XOR, BPF_REG_AX, imm_rnd);
1055 *to++ = BPF_JMP32_REG(from->code, from->dst_reg, BPF_REG_AX,
1056 off);
1057 break;
1058
1059 case BPF_LD | BPF_IMM | BPF_DW:
1060 *to++ = BPF_ALU64_IMM(BPF_MOV, BPF_REG_AX, imm_rnd ^ aux[1].imm);
1061 *to++ = BPF_ALU64_IMM(BPF_XOR, BPF_REG_AX, imm_rnd);
1062 *to++ = BPF_ALU64_IMM(BPF_LSH, BPF_REG_AX, 32);
1063 *to++ = BPF_ALU64_REG(BPF_MOV, aux[0].dst_reg, BPF_REG_AX);
1064 break;
1065 case 0: /* Part 2 of BPF_LD | BPF_IMM | BPF_DW. */
1066 *to++ = BPF_ALU32_IMM(BPF_MOV, BPF_REG_AX, imm_rnd ^ aux[0].imm);
1067 *to++ = BPF_ALU32_IMM(BPF_XOR, BPF_REG_AX, imm_rnd);
1068 if (emit_zext)
1069 *to++ = BPF_ZEXT_REG(BPF_REG_AX);
1070 *to++ = BPF_ALU64_REG(BPF_OR, aux[0].dst_reg, BPF_REG_AX);
1071 break;
1072
1073 case BPF_ST | BPF_MEM | BPF_DW:
1074 case BPF_ST | BPF_MEM | BPF_W:
1075 case BPF_ST | BPF_MEM | BPF_H:
1076 case BPF_ST | BPF_MEM | BPF_B:
1077 *to++ = BPF_ALU64_IMM(BPF_MOV, BPF_REG_AX, imm_rnd ^ from->imm);
1078 *to++ = BPF_ALU64_IMM(BPF_XOR, BPF_REG_AX, imm_rnd);
1079 *to++ = BPF_STX_MEM(from->code, from->dst_reg, BPF_REG_AX, from->off);
1080 break;
1081 }
1082 out:
1083 return to - to_buff;
1084 }
1085
1086 static struct bpf_prog *bpf_prog_clone_create(struct bpf_prog *fp_other,
1087 gfp_t gfp_extra_flags)
1088 {
1089 gfp_t gfp_flags = GFP_KERNEL | __GFP_ZERO | gfp_extra_flags;
1090 struct bpf_prog *fp;
1091
1092 fp = __vmalloc(fp_other->pages * PAGE_SIZE, gfp_flags);
1093 if (fp != NULL) {
1094 /* aux->prog still points to the fp_other one, so
1095 * when promoting the clone to the real program,
1096 * this still needs to be adapted.
1097 */
1098 memcpy(fp, fp_other, fp_other->pages * PAGE_SIZE);
1099 }
1100
1101 return fp;
1102 }
1103
1104 static void bpf_prog_clone_free(struct bpf_prog *fp)
1105 {
1106 /* aux was stolen by the other clone, so we cannot free
1107 * it from this path! It will be freed eventually by the
1108 * other program on release.
1109 *
1110 * At this point, we don't need a deferred release since
1111 * clone is guaranteed to not be locked.
1112 */
1113 fp->aux = NULL;
1114 __bpf_prog_free(fp);
1115 }
1116
1117 void bpf_jit_prog_release_other(struct bpf_prog *fp, struct bpf_prog *fp_other)
1118 {
1119 /* We have to repoint aux->prog to self, as we don't
1120 * know whether fp here is the clone or the original.
1121 */
1122 fp->aux->prog = fp;
1123 bpf_prog_clone_free(fp_other);
1124 }
1125
1126 struct bpf_prog *bpf_jit_blind_constants(struct bpf_prog *prog)
1127 {
1128 struct bpf_insn insn_buff[16], aux[2];
1129 struct bpf_prog *clone, *tmp;
1130 int insn_delta, insn_cnt;
1131 struct bpf_insn *insn;
1132 int i, rewritten;
1133
1134 if (!bpf_jit_blinding_enabled(prog) || prog->blinded)
1135 return prog;
1136
1137 clone = bpf_prog_clone_create(prog, GFP_USER);
1138 if (!clone)
1139 return ERR_PTR(-ENOMEM);
1140
1141 insn_cnt = clone->len;
1142 insn = clone->insnsi;
1143
1144 for (i = 0; i < insn_cnt; i++, insn++) {
1145 /* We temporarily need to hold the original ld64 insn
1146 * so that we can still access the first part in the
1147 * second blinding run.
1148 */
1149 if (insn[0].code == (BPF_LD | BPF_IMM | BPF_DW) &&
1150 insn[1].code == 0)
1151 memcpy(aux, insn, sizeof(aux));
1152
1153 rewritten = bpf_jit_blind_insn(insn, aux, insn_buff,
1154 clone->aux->verifier_zext);
1155 if (!rewritten)
1156 continue;
1157
1158 tmp = bpf_patch_insn_single(clone, i, insn_buff, rewritten);
1159 if (IS_ERR(tmp)) {
1160 /* Patching may have repointed aux->prog during
1161 * realloc from the original one, so we need to
1162 * fix it up here on error.
1163 */
1164 bpf_jit_prog_release_other(prog, clone);
1165 return tmp;
1166 }
1167
1168 clone = tmp;
1169 insn_delta = rewritten - 1;
1170
1171 /* Walk new program and skip insns we just inserted. */
1172 insn = clone->insnsi + i + insn_delta;
1173 insn_cnt += insn_delta;
1174 i += insn_delta;
1175 }
1176
1177 clone->blinded = 1;
1178 return clone;
1179 }
1180 #endif /* CONFIG_BPF_JIT */
1181
1182 /* Base function for offset calculation. Needs to go into .text section,
1183 * therefore keeping it non-static as well; will also be used by JITs
1184 * anyway later on, so do not let the compiler omit it. This also needs
1185 * to go into kallsyms for correlation from e.g. bpftool, so naming
1186 * must not change.
1187 */
1188 noinline u64 __bpf_call_base(u64 r1, u64 r2, u64 r3, u64 r4, u64 r5)
1189 {
1190 return 0;
1191 }
1192 EXPORT_SYMBOL_GPL(__bpf_call_base);
1193
1194 /* All UAPI available opcodes. */
1195 #define BPF_INSN_MAP(INSN_2, INSN_3) \
1196 /* 32 bit ALU operations. */ \
1197 /* Register based. */ \
1198 INSN_3(ALU, ADD, X), \
1199 INSN_3(ALU, SUB, X), \
1200 INSN_3(ALU, AND, X), \
1201 INSN_3(ALU, OR, X), \
1202 INSN_3(ALU, LSH, X), \
1203 INSN_3(ALU, RSH, X), \
1204 INSN_3(ALU, XOR, X), \
1205 INSN_3(ALU, MUL, X), \
1206 INSN_3(ALU, MOV, X), \
1207 INSN_3(ALU, ARSH, X), \
1208 INSN_3(ALU, DIV, X), \
1209 INSN_3(ALU, MOD, X), \
1210 INSN_2(ALU, NEG), \
1211 INSN_3(ALU, END, TO_BE), \
1212 INSN_3(ALU, END, TO_LE), \
1213 /* Immediate based. */ \
1214 INSN_3(ALU, ADD, K), \
1215 INSN_3(ALU, SUB, K), \
1216 INSN_3(ALU, AND, K), \
1217 INSN_3(ALU, OR, K), \
1218 INSN_3(ALU, LSH, K), \
1219 INSN_3(ALU, RSH, K), \
1220 INSN_3(ALU, XOR, K), \
1221 INSN_3(ALU, MUL, K), \
1222 INSN_3(ALU, MOV, K), \
1223 INSN_3(ALU, ARSH, K), \
1224 INSN_3(ALU, DIV, K), \
1225 INSN_3(ALU, MOD, K), \
1226 /* 64 bit ALU operations. */ \
1227 /* Register based. */ \
1228 INSN_3(ALU64, ADD, X), \
1229 INSN_3(ALU64, SUB, X), \
1230 INSN_3(ALU64, AND, X), \
1231 INSN_3(ALU64, OR, X), \
1232 INSN_3(ALU64, LSH, X), \
1233 INSN_3(ALU64, RSH, X), \
1234 INSN_3(ALU64, XOR, X), \
1235 INSN_3(ALU64, MUL, X), \
1236 INSN_3(ALU64, MOV, X), \
1237 INSN_3(ALU64, ARSH, X), \
1238 INSN_3(ALU64, DIV, X), \
1239 INSN_3(ALU64, MOD, X), \
1240 INSN_2(ALU64, NEG), \
1241 /* Immediate based. */ \
1242 INSN_3(ALU64, ADD, K), \
1243 INSN_3(ALU64, SUB, K), \
1244 INSN_3(ALU64, AND, K), \
1245 INSN_3(ALU64, OR, K), \
1246 INSN_3(ALU64, LSH, K), \
1247 INSN_3(ALU64, RSH, K), \
1248 INSN_3(ALU64, XOR, K), \
1249 INSN_3(ALU64, MUL, K), \
1250 INSN_3(ALU64, MOV, K), \
1251 INSN_3(ALU64, ARSH, K), \
1252 INSN_3(ALU64, DIV, K), \
1253 INSN_3(ALU64, MOD, K), \
1254 /* Call instruction. */ \
1255 INSN_2(JMP, CALL), \
1256 /* Exit instruction. */ \
1257 INSN_2(JMP, EXIT), \
1258 /* 32-bit Jump instructions. */ \
1259 /* Register based. */ \
1260 INSN_3(JMP32, JEQ, X), \
1261 INSN_3(JMP32, JNE, X), \
1262 INSN_3(JMP32, JGT, X), \
1263 INSN_3(JMP32, JLT, X), \
1264 INSN_3(JMP32, JGE, X), \
1265 INSN_3(JMP32, JLE, X), \
1266 INSN_3(JMP32, JSGT, X), \
1267 INSN_3(JMP32, JSLT, X), \
1268 INSN_3(JMP32, JSGE, X), \
1269 INSN_3(JMP32, JSLE, X), \
1270 INSN_3(JMP32, JSET, X), \
1271 /* Immediate based. */ \
1272 INSN_3(JMP32, JEQ, K), \
1273 INSN_3(JMP32, JNE, K), \
1274 INSN_3(JMP32, JGT, K), \
1275 INSN_3(JMP32, JLT, K), \
1276 INSN_3(JMP32, JGE, K), \
1277 INSN_3(JMP32, JLE, K), \
1278 INSN_3(JMP32, JSGT, K), \
1279 INSN_3(JMP32, JSLT, K), \
1280 INSN_3(JMP32, JSGE, K), \
1281 INSN_3(JMP32, JSLE, K), \
1282 INSN_3(JMP32, JSET, K), \
1283 /* Jump instructions. */ \
1284 /* Register based. */ \
1285 INSN_3(JMP, JEQ, X), \
1286 INSN_3(JMP, JNE, X), \
1287 INSN_3(JMP, JGT, X), \
1288 INSN_3(JMP, JLT, X), \
1289 INSN_3(JMP, JGE, X), \
1290 INSN_3(JMP, JLE, X), \
1291 INSN_3(JMP, JSGT, X), \
1292 INSN_3(JMP, JSLT, X), \
1293 INSN_3(JMP, JSGE, X), \
1294 INSN_3(JMP, JSLE, X), \
1295 INSN_3(JMP, JSET, X), \
1296 /* Immediate based. */ \
1297 INSN_3(JMP, JEQ, K), \
1298 INSN_3(JMP, JNE, K), \
1299 INSN_3(JMP, JGT, K), \
1300 INSN_3(JMP, JLT, K), \
1301 INSN_3(JMP, JGE, K), \
1302 INSN_3(JMP, JLE, K), \
1303 INSN_3(JMP, JSGT, K), \
1304 INSN_3(JMP, JSLT, K), \
1305 INSN_3(JMP, JSGE, K), \
1306 INSN_3(JMP, JSLE, K), \
1307 INSN_3(JMP, JSET, K), \
1308 INSN_2(JMP, JA), \
1309 /* Store instructions. */ \
1310 /* Register based. */ \
1311 INSN_3(STX, MEM, B), \
1312 INSN_3(STX, MEM, H), \
1313 INSN_3(STX, MEM, W), \
1314 INSN_3(STX, MEM, DW), \
1315 INSN_3(STX, XADD, W), \
1316 INSN_3(STX, XADD, DW), \
1317 /* Immediate based. */ \
1318 INSN_3(ST, MEM, B), \
1319 INSN_3(ST, MEM, H), \
1320 INSN_3(ST, MEM, W), \
1321 INSN_3(ST, MEM, DW), \
1322 /* Load instructions. */ \
1323 /* Register based. */ \
1324 INSN_3(LDX, MEM, B), \
1325 INSN_3(LDX, MEM, H), \
1326 INSN_3(LDX, MEM, W), \
1327 INSN_3(LDX, MEM, DW), \
1328 /* Immediate based. */ \
1329 INSN_3(LD, IMM, DW)
1330
1331 bool bpf_opcode_in_insntable(u8 code)
1332 {
1333 #define BPF_INSN_2_TBL(x, y) [BPF_##x | BPF_##y] = true
1334 #define BPF_INSN_3_TBL(x, y, z) [BPF_##x | BPF_##y | BPF_##z] = true
1335 static const bool public_insntable[256] = {
1336 [0 ... 255] = false,
1337 /* Now overwrite non-defaults ... */
1338 BPF_INSN_MAP(BPF_INSN_2_TBL, BPF_INSN_3_TBL),
1339 /* UAPI exposed, but rewritten opcodes. cBPF carry-over. */
1340 [BPF_LD | BPF_ABS | BPF_B] = true,
1341 [BPF_LD | BPF_ABS | BPF_H] = true,
1342 [BPF_LD | BPF_ABS | BPF_W] = true,
1343 [BPF_LD | BPF_IND | BPF_B] = true,
1344 [BPF_LD | BPF_IND | BPF_H] = true,
1345 [BPF_LD | BPF_IND | BPF_W] = true,
1346 };
1347 #undef BPF_INSN_3_TBL
1348 #undef BPF_INSN_2_TBL
1349 return public_insntable[code];
1350 }
1351
1352 #ifndef CONFIG_BPF_JIT_ALWAYS_ON
1353 u64 __weak bpf_probe_read_kernel(void *dst, u32 size, const void *unsafe_ptr)
1354 {
1355 memset(dst, 0, size);
1356 return -EFAULT;
1357 }
1358
1359 /**
1360 * __bpf_prog_run - run eBPF program on a given context
1361 * @regs: is the array of MAX_BPF_EXT_REG eBPF pseudo-registers
1362 * @insn: is the array of eBPF instructions
1363 * @stack: is the eBPF storage stack
1364 *
1365 * Decode and execute eBPF instructions.
1366 */
1367 static u64 __no_fgcse ___bpf_prog_run(u64 *regs, const struct bpf_insn *insn, u64 *stack)
1368 {
1369 #define BPF_INSN_2_LBL(x, y) [BPF_##x | BPF_##y] = &&x##_##y
1370 #define BPF_INSN_3_LBL(x, y, z) [BPF_##x | BPF_##y | BPF_##z] = &&x##_##y##_##z
1371 static const void * const jumptable[256] __annotate_jump_table = {
1372 [0 ... 255] = &&default_label,
1373 /* Now overwrite non-defaults ... */
1374 BPF_INSN_MAP(BPF_INSN_2_LBL, BPF_INSN_3_LBL),
1375 /* Non-UAPI available opcodes. */
1376 [BPF_JMP | BPF_CALL_ARGS] = &&JMP_CALL_ARGS,
1377 [BPF_JMP | BPF_TAIL_CALL] = &&JMP_TAIL_CALL,
1378 [BPF_LDX | BPF_PROBE_MEM | BPF_B] = &&LDX_PROBE_MEM_B,
1379 [BPF_LDX | BPF_PROBE_MEM | BPF_H] = &&LDX_PROBE_MEM_H,
1380 [BPF_LDX | BPF_PROBE_MEM | BPF_W] = &&LDX_PROBE_MEM_W,
1381 [BPF_LDX | BPF_PROBE_MEM | BPF_DW] = &&LDX_PROBE_MEM_DW,
1382 };
1383 #undef BPF_INSN_3_LBL
1384 #undef BPF_INSN_2_LBL
1385 u32 tail_call_cnt = 0;
1386
1387 #define CONT ({ insn++; goto select_insn; })
1388 #define CONT_JMP ({ insn++; goto select_insn; })
1389
1390 select_insn:
1391 goto *jumptable[insn->code];
1392
1393 /* ALU */
1394 #define ALU(OPCODE, OP) \
1395 ALU64_##OPCODE##_X: \
1396 DST = DST OP SRC; \
1397 CONT; \
1398 ALU_##OPCODE##_X: \
1399 DST = (u32) DST OP (u32) SRC; \
1400 CONT; \
1401 ALU64_##OPCODE##_K: \
1402 DST = DST OP IMM; \
1403 CONT; \
1404 ALU_##OPCODE##_K: \
1405 DST = (u32) DST OP (u32) IMM; \
1406 CONT;
1407
1408 ALU(ADD, +)
1409 ALU(SUB, -)
1410 ALU(AND, &)
1411 ALU(OR, |)
1412 ALU(LSH, <<)
1413 ALU(RSH, >>)
1414 ALU(XOR, ^)
1415 ALU(MUL, *)
1416 #undef ALU
1417 ALU_NEG:
1418 DST = (u32) -DST;
1419 CONT;
1420 ALU64_NEG:
1421 DST = -DST;
1422 CONT;
1423 ALU_MOV_X:
1424 DST = (u32) SRC;
1425 CONT;
1426 ALU_MOV_K:
1427 DST = (u32) IMM;
1428 CONT;
1429 ALU64_MOV_X:
1430 DST = SRC;
1431 CONT;
1432 ALU64_MOV_K:
1433 DST = IMM;
1434 CONT;
1435 LD_IMM_DW:
1436 DST = (u64) (u32) insn[0].imm | ((u64) (u32) insn[1].imm) << 32;
1437 insn++;
1438 CONT;
1439 ALU_ARSH_X:
1440 DST = (u64) (u32) (((s32) DST) >> SRC);
1441 CONT;
1442 ALU_ARSH_K:
1443 DST = (u64) (u32) (((s32) DST) >> IMM);
1444 CONT;
1445 ALU64_ARSH_X:
1446 (*(s64 *) &DST) >>= SRC;
1447 CONT;
1448 ALU64_ARSH_K:
1449 (*(s64 *) &DST) >>= IMM;
1450 CONT;
1451 ALU64_MOD_X:
1452 div64_u64_rem(DST, SRC, &AX);
1453 DST = AX;
1454 CONT;
1455 ALU_MOD_X:
1456 AX = (u32) DST;
1457 DST = do_div(AX, (u32) SRC);
1458 CONT;
1459 ALU64_MOD_K:
1460 div64_u64_rem(DST, IMM, &AX);
1461 DST = AX;
1462 CONT;
1463 ALU_MOD_K:
1464 AX = (u32) DST;
1465 DST = do_div(AX, (u32) IMM);
1466 CONT;
1467 ALU64_DIV_X:
1468 DST = div64_u64(DST, SRC);
1469 CONT;
1470 ALU_DIV_X:
1471 AX = (u32) DST;
1472 do_div(AX, (u32) SRC);
1473 DST = (u32) AX;
1474 CONT;
1475 ALU64_DIV_K:
1476 DST = div64_u64(DST, IMM);
1477 CONT;
1478 ALU_DIV_K:
1479 AX = (u32) DST;
1480 do_div(AX, (u32) IMM);
1481 DST = (u32) AX;
1482 CONT;
1483 ALU_END_TO_BE:
1484 switch (IMM) {
1485 case 16:
1486 DST = (__force u16) cpu_to_be16(DST);
1487 break;
1488 case 32:
1489 DST = (__force u32) cpu_to_be32(DST);
1490 break;
1491 case 64:
1492 DST = (__force u64) cpu_to_be64(DST);
1493 break;
1494 }
1495 CONT;
1496 ALU_END_TO_LE:
1497 switch (IMM) {
1498 case 16:
1499 DST = (__force u16) cpu_to_le16(DST);
1500 break;
1501 case 32:
1502 DST = (__force u32) cpu_to_le32(DST);
1503 break;
1504 case 64:
1505 DST = (__force u64) cpu_to_le64(DST);
1506 break;
1507 }
1508 CONT;
1509
1510 /* CALL */
1511 JMP_CALL:
1512 /* Function call scratches BPF_R1-BPF_R5 registers,
1513 * preserves BPF_R6-BPF_R9, and stores return value
1514 * into BPF_R0.
1515 */
1516 BPF_R0 = (__bpf_call_base + insn->imm)(BPF_R1, BPF_R2, BPF_R3,
1517 BPF_R4, BPF_R5);
1518 CONT;
1519
1520 JMP_CALL_ARGS:
1521 BPF_R0 = (__bpf_call_base_args + insn->imm)(BPF_R1, BPF_R2,
1522 BPF_R3, BPF_R4,
1523 BPF_R5,
1524 insn + insn->off + 1);
1525 CONT;
1526
1527 JMP_TAIL_CALL: {
1528 struct bpf_map *map = (struct bpf_map *) (unsigned long) BPF_R2;
1529 struct bpf_array *array = container_of(map, struct bpf_array, map);
1530 struct bpf_prog *prog;
1531 u32 index = BPF_R3;
1532
1533 if (unlikely(index >= array->map.max_entries))
1534 goto out;
1535 if (unlikely(tail_call_cnt > MAX_TAIL_CALL_CNT))
1536 goto out;
1537
1538 tail_call_cnt++;
1539
1540 prog = READ_ONCE(array->ptrs[index]);
1541 if (!prog)
1542 goto out;
1543
1544 /* ARG1 at this point is guaranteed to point to CTX from
1545 * the verifier side due to the fact that the tail call is
1546 * handled like a helper, that is, bpf_tail_call_proto,
1547 * where arg1_type is ARG_PTR_TO_CTX.
1548 */
1549 insn = prog->insnsi;
1550 goto select_insn;
1551 out:
1552 CONT;
1553 }
1554 JMP_JA:
1555 insn += insn->off;
1556 CONT;
1557 JMP_EXIT:
1558 return BPF_R0;
1559 /* JMP */
1560 #define COND_JMP(SIGN, OPCODE, CMP_OP) \
1561 JMP_##OPCODE##_X: \
1562 if ((SIGN##64) DST CMP_OP (SIGN##64) SRC) { \
1563 insn += insn->off; \
1564 CONT_JMP; \
1565 } \
1566 CONT; \
1567 JMP32_##OPCODE##_X: \
1568 if ((SIGN##32) DST CMP_OP (SIGN##32) SRC) { \
1569 insn += insn->off; \
1570 CONT_JMP; \
1571 } \
1572 CONT; \
1573 JMP_##OPCODE##_K: \
1574 if ((SIGN##64) DST CMP_OP (SIGN##64) IMM) { \
1575 insn += insn->off; \
1576 CONT_JMP; \
1577 } \
1578 CONT; \
1579 JMP32_##OPCODE##_K: \
1580 if ((SIGN##32) DST CMP_OP (SIGN##32) IMM) { \
1581 insn += insn->off; \
1582 CONT_JMP; \
1583 } \
1584 CONT;
1585 COND_JMP(u, JEQ, ==)
1586 COND_JMP(u, JNE, !=)
1587 COND_JMP(u, JGT, >)
1588 COND_JMP(u, JLT, <)
1589 COND_JMP(u, JGE, >=)
1590 COND_JMP(u, JLE, <=)
1591 COND_JMP(u, JSET, &)
1592 COND_JMP(s, JSGT, >)
1593 COND_JMP(s, JSLT, <)
1594 COND_JMP(s, JSGE, >=)
1595 COND_JMP(s, JSLE, <=)
1596 #undef COND_JMP
1597 /* STX and ST and LDX*/
1598 #define LDST(SIZEOP, SIZE) \
1599 STX_MEM_##SIZEOP: \
1600 *(SIZE *)(unsigned long) (DST + insn->off) = SRC; \
1601 CONT; \
1602 ST_MEM_##SIZEOP: \
1603 *(SIZE *)(unsigned long) (DST + insn->off) = IMM; \
1604 CONT; \
1605 LDX_MEM_##SIZEOP: \
1606 DST = *(SIZE *)(unsigned long) (SRC + insn->off); \
1607 CONT;
1608
1609 LDST(B, u8)
1610 LDST(H, u16)
1611 LDST(W, u32)
1612 LDST(DW, u64)
1613 #undef LDST
1614 #define LDX_PROBE(SIZEOP, SIZE) \
1615 LDX_PROBE_MEM_##SIZEOP: \
1616 bpf_probe_read_kernel(&DST, SIZE, (const void *)(long) (SRC + insn->off)); \
1617 CONT;
1618 LDX_PROBE(B, 1)
1619 LDX_PROBE(H, 2)
1620 LDX_PROBE(W, 4)
1621 LDX_PROBE(DW, 8)
1622 #undef LDX_PROBE
1623
1624 STX_XADD_W: /* lock xadd *(u32 *)(dst_reg + off16) += src_reg */
1625 atomic_add((u32) SRC, (atomic_t *)(unsigned long)
1626 (DST + insn->off));
1627 CONT;
1628 STX_XADD_DW: /* lock xadd *(u64 *)(dst_reg + off16) += src_reg */
1629 atomic64_add((u64) SRC, (atomic64_t *)(unsigned long)
1630 (DST + insn->off));
1631 CONT;
1632
1633 default_label:
1634 /* If we ever reach this, we have a bug somewhere. Die hard here
1635 * instead of just returning 0; we could be somewhere in a subprog,
1636 * so execution could continue otherwise which we do /not/ want.
1637 *
1638 * Note, verifier whitelists all opcodes in bpf_opcode_in_insntable().
1639 */
1640 pr_warn("BPF interpreter: unknown opcode %02x\n", insn->code);
1641 BUG_ON(1);
1642 return 0;
1643 }
1644
1645 #define PROG_NAME(stack_size) __bpf_prog_run##stack_size
1646 #define DEFINE_BPF_PROG_RUN(stack_size) \
1647 static unsigned int PROG_NAME(stack_size)(const void *ctx, const struct bpf_insn *insn) \
1648 { \
1649 u64 stack[stack_size / sizeof(u64)]; \
1650 u64 regs[MAX_BPF_EXT_REG]; \
1651 \
1652 FP = (u64) (unsigned long) &stack[ARRAY_SIZE(stack)]; \
1653 ARG1 = (u64) (unsigned long) ctx; \
1654 return ___bpf_prog_run(regs, insn, stack); \
1655 }
1656
1657 #define PROG_NAME_ARGS(stack_size) __bpf_prog_run_args##stack_size
1658 #define DEFINE_BPF_PROG_RUN_ARGS(stack_size) \
1659 static u64 PROG_NAME_ARGS(stack_size)(u64 r1, u64 r2, u64 r3, u64 r4, u64 r5, \
1660 const struct bpf_insn *insn) \
1661 { \
1662 u64 stack[stack_size / sizeof(u64)]; \
1663 u64 regs[MAX_BPF_EXT_REG]; \
1664 \
1665 FP = (u64) (unsigned long) &stack[ARRAY_SIZE(stack)]; \
1666 BPF_R1 = r1; \
1667 BPF_R2 = r2; \
1668 BPF_R3 = r3; \
1669 BPF_R4 = r4; \
1670 BPF_R5 = r5; \
1671 return ___bpf_prog_run(regs, insn, stack); \
1672 }
1673
1674 #define EVAL1(FN, X) FN(X)
1675 #define EVAL2(FN, X, Y...) FN(X) EVAL1(FN, Y)
1676 #define EVAL3(FN, X, Y...) FN(X) EVAL2(FN, Y)
1677 #define EVAL4(FN, X, Y...) FN(X) EVAL3(FN, Y)
1678 #define EVAL5(FN, X, Y...) FN(X) EVAL4(FN, Y)
1679 #define EVAL6(FN, X, Y...) FN(X) EVAL5(FN, Y)
1680
1681 EVAL6(DEFINE_BPF_PROG_RUN, 32, 64, 96, 128, 160, 192);
1682 EVAL6(DEFINE_BPF_PROG_RUN, 224, 256, 288, 320, 352, 384);
1683 EVAL4(DEFINE_BPF_PROG_RUN, 416, 448, 480, 512);
1684
1685 EVAL6(DEFINE_BPF_PROG_RUN_ARGS, 32, 64, 96, 128, 160, 192);
1686 EVAL6(DEFINE_BPF_PROG_RUN_ARGS, 224, 256, 288, 320, 352, 384);
1687 EVAL4(DEFINE_BPF_PROG_RUN_ARGS, 416, 448, 480, 512);
1688
1689 #define PROG_NAME_LIST(stack_size) PROG_NAME(stack_size),
1690
1691 static unsigned int (*interpreters[])(const void *ctx,
1692 const struct bpf_insn *insn) = {
1693 EVAL6(PROG_NAME_LIST, 32, 64, 96, 128, 160, 192)
1694 EVAL6(PROG_NAME_LIST, 224, 256, 288, 320, 352, 384)
1695 EVAL4(PROG_NAME_LIST, 416, 448, 480, 512)
1696 };
1697 #undef PROG_NAME_LIST
1698 #define PROG_NAME_LIST(stack_size) PROG_NAME_ARGS(stack_size),
1699 static u64 (*interpreters_args[])(u64 r1, u64 r2, u64 r3, u64 r4, u64 r5,
1700 const struct bpf_insn *insn) = {
1701 EVAL6(PROG_NAME_LIST, 32, 64, 96, 128, 160, 192)
1702 EVAL6(PROG_NAME_LIST, 224, 256, 288, 320, 352, 384)
1703 EVAL4(PROG_NAME_LIST, 416, 448, 480, 512)
1704 };
1705 #undef PROG_NAME_LIST
1706
1707 void bpf_patch_call_args(struct bpf_insn *insn, u32 stack_depth)
1708 {
1709 stack_depth = max_t(u32, stack_depth, 1);
1710 insn->off = (s16) insn->imm;
1711 insn->imm = interpreters_args[(round_up(stack_depth, 32) / 32) - 1] -
1712 __bpf_call_base_args;
1713 insn->code = BPF_JMP | BPF_CALL_ARGS;
1714 }
1715
1716 #else
1717 static unsigned int __bpf_prog_ret0_warn(const void *ctx,
1718 const struct bpf_insn *insn)
1719 {
1720 /* If this handler ever gets executed, then BPF_JIT_ALWAYS_ON
1721 * is not working properly, so warn about it!
1722 */
1723 WARN_ON_ONCE(1);
1724 return 0;
1725 }
1726 #endif
1727
1728 bool bpf_prog_array_compatible(struct bpf_array *array,
1729 const struct bpf_prog *fp)
1730 {
1731 if (fp->kprobe_override)
1732 return false;
1733
1734 if (!array->aux->type) {
1735 /* There's no owner yet where we could check for
1736 * compatibility.
1737 */
1738 array->aux->type = fp->type;
1739 array->aux->jited = fp->jited;
1740 return true;
1741 }
1742
1743 return array->aux->type == fp->type &&
1744 array->aux->jited == fp->jited;
1745 }
1746
1747 static int bpf_check_tail_call(const struct bpf_prog *fp)
1748 {
1749 struct bpf_prog_aux *aux = fp->aux;
1750 int i;
1751
1752 for (i = 0; i < aux->used_map_cnt; i++) {
1753 struct bpf_map *map = aux->used_maps[i];
1754 struct bpf_array *array;
1755
1756 if (map->map_type != BPF_MAP_TYPE_PROG_ARRAY)
1757 continue;
1758
1759 array = container_of(map, struct bpf_array, map);
1760 if (!bpf_prog_array_compatible(array, fp))
1761 return -EINVAL;
1762 }
1763
1764 return 0;
1765 }
1766
1767 static void bpf_prog_select_func(struct bpf_prog *fp)
1768 {
1769 #ifndef CONFIG_BPF_JIT_ALWAYS_ON
1770 u32 stack_depth = max_t(u32, fp->aux->stack_depth, 1);
1771
1772 fp->bpf_func = interpreters[(round_up(stack_depth, 32) / 32) - 1];
1773 #else
1774 fp->bpf_func = __bpf_prog_ret0_warn;
1775 #endif
1776 }
1777
1778 /**
1779 * bpf_prog_select_runtime - select exec runtime for BPF program
1780 * @fp: bpf_prog populated with internal BPF program
1781 * @err: pointer to error variable
1782 *
1783 * Try to JIT eBPF program, if JIT is not available, use interpreter.
1784 * The BPF program will be executed via BPF_PROG_RUN() macro.
1785 */
1786 struct bpf_prog *bpf_prog_select_runtime(struct bpf_prog *fp, int *err)
1787 {
1788 /* In case of BPF to BPF calls, verifier did all the prep
1789 * work with regards to JITing, etc.
1790 */
1791 if (fp->bpf_func)
1792 goto finalize;
1793
1794 bpf_prog_select_func(fp);
1795
1796 /* eBPF JITs can rewrite the program in case constant
1797 * blinding is active. However, in case of error during
1798 * blinding, bpf_int_jit_compile() must always return a
1799 * valid program, which in this case would simply not
1800 * be JITed, but falls back to the interpreter.
1801 */
1802 if (!bpf_prog_is_dev_bound(fp->aux)) {
1803 *err = bpf_prog_alloc_jited_linfo(fp);
1804 if (*err)
1805 return fp;
1806
1807 fp = bpf_int_jit_compile(fp);
1808 if (!fp->jited) {
1809 bpf_prog_free_jited_linfo(fp);
1810 #ifdef CONFIG_BPF_JIT_ALWAYS_ON
1811 *err = -ENOTSUPP;
1812 return fp;
1813 #endif
1814 } else {
1815 bpf_prog_free_unused_jited_linfo(fp);
1816 }
1817 } else {
1818 *err = bpf_prog_offload_compile(fp);
1819 if (*err)
1820 return fp;
1821 }
1822
1823 finalize:
1824 bpf_prog_lock_ro(fp);
1825
1826 /* The tail call compatibility check can only be done at
1827 * this late stage as we need to determine, if we deal
1828 * with JITed or non JITed program concatenations and not
1829 * all eBPF JITs might immediately support all features.
1830 */
1831 *err = bpf_check_tail_call(fp);
1832
1833 return fp;
1834 }
1835 EXPORT_SYMBOL_GPL(bpf_prog_select_runtime);
1836
1837 static unsigned int __bpf_prog_ret1(const void *ctx,
1838 const struct bpf_insn *insn)
1839 {
1840 return 1;
1841 }
1842
1843 static struct bpf_prog_dummy {
1844 struct bpf_prog prog;
1845 } dummy_bpf_prog = {
1846 .prog = {
1847 .bpf_func = __bpf_prog_ret1,
1848 },
1849 };
1850
1851 /* to avoid allocating empty bpf_prog_array for cgroups that
1852 * don't have bpf program attached use one global 'empty_prog_array'
1853 * It will not be modified the caller of bpf_prog_array_alloc()
1854 * (since caller requested prog_cnt == 0)
1855 * that pointer should be 'freed' by bpf_prog_array_free()
1856 */
1857 static struct {
1858 struct bpf_prog_array hdr;
1859 struct bpf_prog *null_prog;
1860 } empty_prog_array = {
1861 .null_prog = NULL,
1862 };
1863
1864 struct bpf_prog_array *bpf_prog_array_alloc(u32 prog_cnt, gfp_t flags)
1865 {
1866 if (prog_cnt)
1867 return kzalloc(sizeof(struct bpf_prog_array) +
1868 sizeof(struct bpf_prog_array_item) *
1869 (prog_cnt + 1),
1870 flags);
1871
1872 return &empty_prog_array.hdr;
1873 }
1874
1875 void bpf_prog_array_free(struct bpf_prog_array *progs)
1876 {
1877 if (!progs || progs == &empty_prog_array.hdr)
1878 return;
1879 kfree_rcu(progs, rcu);
1880 }
1881
1882 int bpf_prog_array_length(struct bpf_prog_array *array)
1883 {
1884 struct bpf_prog_array_item *item;
1885 u32 cnt = 0;
1886
1887 for (item = array->items; item->prog; item++)
1888 if (item->prog != &dummy_bpf_prog.prog)
1889 cnt++;
1890 return cnt;
1891 }
1892
1893 bool bpf_prog_array_is_empty(struct bpf_prog_array *array)
1894 {
1895 struct bpf_prog_array_item *item;
1896
1897 for (item = array->items; item->prog; item++)
1898 if (item->prog != &dummy_bpf_prog.prog)
1899 return false;
1900 return true;
1901 }
1902
1903 static bool bpf_prog_array_copy_core(struct bpf_prog_array *array,
1904 u32 *prog_ids,
1905 u32 request_cnt)
1906 {
1907 struct bpf_prog_array_item *item;
1908 int i = 0;
1909
1910 for (item = array->items; item->prog; item++) {
1911 if (item->prog == &dummy_bpf_prog.prog)
1912 continue;
1913 prog_ids[i] = item->prog->aux->id;
1914 if (++i == request_cnt) {
1915 item++;
1916 break;
1917 }
1918 }
1919
1920 return !!(item->prog);
1921 }
1922
1923 int bpf_prog_array_copy_to_user(struct bpf_prog_array *array,
1924 __u32 __user *prog_ids, u32 cnt)
1925 {
1926 unsigned long err = 0;
1927 bool nospc;
1928 u32 *ids;
1929
1930 /* users of this function are doing:
1931 * cnt = bpf_prog_array_length();
1932 * if (cnt > 0)
1933 * bpf_prog_array_copy_to_user(..., cnt);
1934 * so below kcalloc doesn't need extra cnt > 0 check.
1935 */
1936 ids = kcalloc(cnt, sizeof(u32), GFP_USER | __GFP_NOWARN);
1937 if (!ids)
1938 return -ENOMEM;
1939 nospc = bpf_prog_array_copy_core(array, ids, cnt);
1940 err = copy_to_user(prog_ids, ids, cnt * sizeof(u32));
1941 kfree(ids);
1942 if (err)
1943 return -EFAULT;
1944 if (nospc)
1945 return -ENOSPC;
1946 return 0;
1947 }
1948
1949 void bpf_prog_array_delete_safe(struct bpf_prog_array *array,
1950 struct bpf_prog *old_prog)
1951 {
1952 struct bpf_prog_array_item *item;
1953
1954 for (item = array->items; item->prog; item++)
1955 if (item->prog == old_prog) {
1956 WRITE_ONCE(item->prog, &dummy_bpf_prog.prog);
1957 break;
1958 }
1959 }
1960
1961 int bpf_prog_array_copy(struct bpf_prog_array *old_array,
1962 struct bpf_prog *exclude_prog,
1963 struct bpf_prog *include_prog,
1964 struct bpf_prog_array **new_array)
1965 {
1966 int new_prog_cnt, carry_prog_cnt = 0;
1967 struct bpf_prog_array_item *existing;
1968 struct bpf_prog_array *array;
1969 bool found_exclude = false;
1970 int new_prog_idx = 0;
1971
1972 /* Figure out how many existing progs we need to carry over to
1973 * the new array.
1974 */
1975 if (old_array) {
1976 existing = old_array->items;
1977 for (; existing->prog; existing++) {
1978 if (existing->prog == exclude_prog) {
1979 found_exclude = true;
1980 continue;
1981 }
1982 if (existing->prog != &dummy_bpf_prog.prog)
1983 carry_prog_cnt++;
1984 if (existing->prog == include_prog)
1985 return -EEXIST;
1986 }
1987 }
1988
1989 if (exclude_prog && !found_exclude)
1990 return -ENOENT;
1991
1992 /* How many progs (not NULL) will be in the new array? */
1993 new_prog_cnt = carry_prog_cnt;
1994 if (include_prog)
1995 new_prog_cnt += 1;
1996
1997 /* Do we have any prog (not NULL) in the new array? */
1998 if (!new_prog_cnt) {
1999 *new_array = NULL;
2000 return 0;
2001 }
2002
2003 /* +1 as the end of prog_array is marked with NULL */
2004 array = bpf_prog_array_alloc(new_prog_cnt + 1, GFP_KERNEL);
2005 if (!array)
2006 return -ENOMEM;
2007
2008 /* Fill in the new prog array */
2009 if (carry_prog_cnt) {
2010 existing = old_array->items;
2011 for (; existing->prog; existing++)
2012 if (existing->prog != exclude_prog &&
2013 existing->prog != &dummy_bpf_prog.prog) {
2014 array->items[new_prog_idx++].prog =
2015 existing->prog;
2016 }
2017 }
2018 if (include_prog)
2019 array->items[new_prog_idx++].prog = include_prog;
2020 array->items[new_prog_idx].prog = NULL;
2021 *new_array = array;
2022 return 0;
2023 }
2024
2025 int bpf_prog_array_copy_info(struct bpf_prog_array *array,
2026 u32 *prog_ids, u32 request_cnt,
2027 u32 *prog_cnt)
2028 {
2029 u32 cnt = 0;
2030
2031 if (array)
2032 cnt = bpf_prog_array_length(array);
2033
2034 *prog_cnt = cnt;
2035
2036 /* return early if user requested only program count or nothing to copy */
2037 if (!request_cnt || !cnt)
2038 return 0;
2039
2040 /* this function is called under trace/bpf_trace.c: bpf_event_mutex */
2041 return bpf_prog_array_copy_core(array, prog_ids, request_cnt) ? -ENOSPC
2042 : 0;
2043 }
2044
2045 static void bpf_free_cgroup_storage(struct bpf_prog_aux *aux)
2046 {
2047 enum bpf_cgroup_storage_type stype;
2048
2049 for_each_cgroup_storage_type(stype) {
2050 if (!aux->cgroup_storage[stype])
2051 continue;
2052 bpf_cgroup_storage_release(aux, aux->cgroup_storage[stype]);
2053 }
2054 }
2055
2056 void __bpf_free_used_maps(struct bpf_prog_aux *aux,
2057 struct bpf_map **used_maps, u32 len)
2058 {
2059 struct bpf_map *map;
2060 u32 i;
2061
2062 bpf_free_cgroup_storage(aux);
2063 for (i = 0; i < len; i++) {
2064 map = used_maps[i];
2065 if (map->ops->map_poke_untrack)
2066 map->ops->map_poke_untrack(map, aux);
2067 bpf_map_put(map);
2068 }
2069 }
2070
2071 static void bpf_free_used_maps(struct bpf_prog_aux *aux)
2072 {
2073 __bpf_free_used_maps(aux, aux->used_maps, aux->used_map_cnt);
2074 kfree(aux->used_maps);
2075 }
2076
2077 static void bpf_prog_free_deferred(struct work_struct *work)
2078 {
2079 struct bpf_prog_aux *aux;
2080 int i;
2081
2082 aux = container_of(work, struct bpf_prog_aux, work);
2083 bpf_free_used_maps(aux);
2084 if (bpf_prog_is_dev_bound(aux))
2085 bpf_prog_offload_destroy(aux->prog);
2086 #ifdef CONFIG_PERF_EVENTS
2087 if (aux->prog->has_callchain_buf)
2088 put_callchain_buffers();
2089 #endif
2090 bpf_trampoline_put(aux->trampoline);
2091 for (i = 0; i < aux->func_cnt; i++)
2092 bpf_jit_free(aux->func[i]);
2093 if (aux->func_cnt) {
2094 kfree(aux->func);
2095 bpf_prog_unlock_free(aux->prog);
2096 } else {
2097 bpf_jit_free(aux->prog);
2098 }
2099 }
2100
2101 /* Free internal BPF program */
2102 void bpf_prog_free(struct bpf_prog *fp)
2103 {
2104 struct bpf_prog_aux *aux = fp->aux;
2105
2106 if (aux->linked_prog)
2107 bpf_prog_put(aux->linked_prog);
2108 INIT_WORK(&aux->work, bpf_prog_free_deferred);
2109 schedule_work(&aux->work);
2110 }
2111 EXPORT_SYMBOL_GPL(bpf_prog_free);
2112
2113 /* RNG for unpriviledged user space with separated state from prandom_u32(). */
2114 static DEFINE_PER_CPU(struct rnd_state, bpf_user_rnd_state);
2115
2116 void bpf_user_rnd_init_once(void)
2117 {
2118 prandom_init_once(&bpf_user_rnd_state);
2119 }
2120
2121 BPF_CALL_0(bpf_user_rnd_u32)
2122 {
2123 /* Should someone ever have the rather unwise idea to use some
2124 * of the registers passed into this function, then note that
2125 * this function is called from native eBPF and classic-to-eBPF
2126 * transformations. Register assignments from both sides are
2127 * different, f.e. classic always sets fn(ctx, A, X) here.
2128 */
2129 struct rnd_state *state;
2130 u32 res;
2131
2132 state = &get_cpu_var(bpf_user_rnd_state);
2133 res = prandom_u32_state(state);
2134 put_cpu_var(bpf_user_rnd_state);
2135
2136 return res;
2137 }
2138
2139 BPF_CALL_0(bpf_get_raw_cpu_id)
2140 {
2141 return raw_smp_processor_id();
2142 }
2143
2144 /* Weak definitions of helper functions in case we don't have bpf syscall. */
2145 const struct bpf_func_proto bpf_map_lookup_elem_proto __weak;
2146 const struct bpf_func_proto bpf_map_update_elem_proto __weak;
2147 const struct bpf_func_proto bpf_map_delete_elem_proto __weak;
2148 const struct bpf_func_proto bpf_map_push_elem_proto __weak;
2149 const struct bpf_func_proto bpf_map_pop_elem_proto __weak;
2150 const struct bpf_func_proto bpf_map_peek_elem_proto __weak;
2151 const struct bpf_func_proto bpf_spin_lock_proto __weak;
2152 const struct bpf_func_proto bpf_spin_unlock_proto __weak;
2153 const struct bpf_func_proto bpf_jiffies64_proto __weak;
2154
2155 const struct bpf_func_proto bpf_get_prandom_u32_proto __weak;
2156 const struct bpf_func_proto bpf_get_smp_processor_id_proto __weak;
2157 const struct bpf_func_proto bpf_get_numa_node_id_proto __weak;
2158 const struct bpf_func_proto bpf_ktime_get_ns_proto __weak;
2159 const struct bpf_func_proto bpf_ktime_get_boot_ns_proto __weak;
2160
2161 const struct bpf_func_proto bpf_get_current_pid_tgid_proto __weak;
2162 const struct bpf_func_proto bpf_get_current_uid_gid_proto __weak;
2163 const struct bpf_func_proto bpf_get_current_comm_proto __weak;
2164 const struct bpf_func_proto bpf_get_current_cgroup_id_proto __weak;
2165 const struct bpf_func_proto bpf_get_current_ancestor_cgroup_id_proto __weak;
2166 const struct bpf_func_proto bpf_get_local_storage_proto __weak;
2167 const struct bpf_func_proto bpf_get_ns_current_pid_tgid_proto __weak;
2168
2169 const struct bpf_func_proto * __weak bpf_get_trace_printk_proto(void)
2170 {
2171 return NULL;
2172 }
2173
2174 u64 __weak
2175 bpf_event_output(struct bpf_map *map, u64 flags, void *meta, u64 meta_size,
2176 void *ctx, u64 ctx_size, bpf_ctx_copy_t ctx_copy)
2177 {
2178 return -ENOTSUPP;
2179 }
2180 EXPORT_SYMBOL_GPL(bpf_event_output);
2181
2182 /* Always built-in helper functions. */
2183 const struct bpf_func_proto bpf_tail_call_proto = {
2184 .func = NULL,
2185 .gpl_only = false,
2186 .ret_type = RET_VOID,
2187 .arg1_type = ARG_PTR_TO_CTX,
2188 .arg2_type = ARG_CONST_MAP_PTR,
2189 .arg3_type = ARG_ANYTHING,
2190 };
2191
2192 /* Stub for JITs that only support cBPF. eBPF programs are interpreted.
2193 * It is encouraged to implement bpf_int_jit_compile() instead, so that
2194 * eBPF and implicitly also cBPF can get JITed!
2195 */
2196 struct bpf_prog * __weak bpf_int_jit_compile(struct bpf_prog *prog)
2197 {
2198 return prog;
2199 }
2200
2201 /* Stub for JITs that support eBPF. All cBPF code gets transformed into
2202 * eBPF by the kernel and is later compiled by bpf_int_jit_compile().
2203 */
2204 void __weak bpf_jit_compile(struct bpf_prog *prog)
2205 {
2206 }
2207
2208 bool __weak bpf_helper_changes_pkt_data(void *func)
2209 {
2210 return false;
2211 }
2212
2213 /* Return TRUE if the JIT backend wants verifier to enable sub-register usage
2214 * analysis code and wants explicit zero extension inserted by verifier.
2215 * Otherwise, return FALSE.
2216 */
2217 bool __weak bpf_jit_needs_zext(void)
2218 {
2219 return false;
2220 }
2221
2222 /* To execute LD_ABS/LD_IND instructions __bpf_prog_run() may call
2223 * skb_copy_bits(), so provide a weak definition of it for NET-less config.
2224 */
2225 int __weak skb_copy_bits(const struct sk_buff *skb, int offset, void *to,
2226 int len)
2227 {
2228 return -EFAULT;
2229 }
2230
2231 int __weak bpf_arch_text_poke(void *ip, enum bpf_text_poke_type t,
2232 void *addr1, void *addr2)
2233 {
2234 return -ENOTSUPP;
2235 }
2236
2237 DEFINE_STATIC_KEY_FALSE(bpf_stats_enabled_key);
2238 EXPORT_SYMBOL(bpf_stats_enabled_key);
2239
2240 /* All definitions of tracepoints related to BPF. */
2241 #define CREATE_TRACE_POINTS
2242 #include <linux/bpf_trace.h>
2243
2244 EXPORT_TRACEPOINT_SYMBOL_GPL(xdp_exception);
2245 EXPORT_TRACEPOINT_SYMBOL_GPL(xdp_bulk_tx);
Linux with added FPC-III support