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clk: samsung: dt-bindings: Add ADC clock ID to Exynos5410
[linux/fpc-iii.git] / kernel / bpf / core.c
blobff09d32a8a1be210e88a0e6f7f14596ee6b89f06
1 /*
2 * Linux Socket Filter - Kernel level socket filtering
3 *
4 * Based on the design of the Berkeley Packet Filter. The new
5 * internal format has been designed by PLUMgrid:
6 *
7 * Copyright (c) 2011 - 2014 PLUMgrid, http://plumgrid.com
8 *
9 * Authors:
10 *
11 * Jay Schulist <jschlst@samba.org>
12 * Alexei Starovoitov <ast@plumgrid.com>
13 * Daniel Borkmann <dborkman@redhat.com>
14 *
15 * This program is free software; you can redistribute it and/or
16 * modify it under the terms of the GNU General Public License
17 * as published by the Free Software Foundation; either version
18 * 2 of the License, or (at your option) any later version.
19 *
20 * Andi Kleen - Fix a few bad bugs and races.
21 * Kris Katterjohn - Added many additional checks in bpf_check_classic()
22 */
23
24 #include <uapi/linux/btf.h>
25 #include <linux/filter.h>
26 #include <linux/skbuff.h>
27 #include <linux/vmalloc.h>
28 #include <linux/random.h>
29 #include <linux/moduleloader.h>
30 #include <linux/bpf.h>
31 #include <linux/btf.h>
32 #include <linux/frame.h>
33 #include <linux/rbtree_latch.h>
34 #include <linux/kallsyms.h>
35 #include <linux/rcupdate.h>
36 #include <linux/perf_event.h>
37
38 #include <asm/unaligned.h>
39
40 /* Registers */
41 #define BPF_R0 regs[BPF_REG_0]
42 #define BPF_R1 regs[BPF_REG_1]
43 #define BPF_R2 regs[BPF_REG_2]
44 #define BPF_R3 regs[BPF_REG_3]
45 #define BPF_R4 regs[BPF_REG_4]
46 #define BPF_R5 regs[BPF_REG_5]
47 #define BPF_R6 regs[BPF_REG_6]
48 #define BPF_R7 regs[BPF_REG_7]
49 #define BPF_R8 regs[BPF_REG_8]
50 #define BPF_R9 regs[BPF_REG_9]
51 #define BPF_R10 regs[BPF_REG_10]
52
53 /* Named registers */
54 #define DST regs[insn->dst_reg]
55 #define SRC regs[insn->src_reg]
56 #define FP regs[BPF_REG_FP]
57 #define AX regs[BPF_REG_AX]
58 #define ARG1 regs[BPF_REG_ARG1]
59 #define CTX regs[BPF_REG_CTX]
60 #define IMM insn->imm
61
62 /* No hurry in this branch
63 *
64 * Exported for the bpf jit load helper.
65 */
66 void *bpf_internal_load_pointer_neg_helper(const struct sk_buff *skb, int k, unsigned int size)
67 {
68 u8 *ptr = NULL;
69
70 if (k >= SKF_NET_OFF)
71 ptr = skb_network_header(skb) + k - SKF_NET_OFF;
72 else if (k >= SKF_LL_OFF)
73 ptr = skb_mac_header(skb) + k - SKF_LL_OFF;
74
75 if (ptr >= skb->head && ptr + size <= skb_tail_pointer(skb))
76 return ptr;
77
78 return NULL;
79 }
80
81 struct bpf_prog *bpf_prog_alloc_no_stats(unsigned int size, gfp_t gfp_extra_flags)
82 {
83 gfp_t gfp_flags = GFP_KERNEL | __GFP_ZERO | gfp_extra_flags;
84 struct bpf_prog_aux *aux;
85 struct bpf_prog *fp;
86
87 size = round_up(size, PAGE_SIZE);
88 fp = __vmalloc(size, gfp_flags, PAGE_KERNEL);
89 if (fp == NULL)
90 return NULL;
91
92 aux = kzalloc(sizeof(*aux), GFP_KERNEL | gfp_extra_flags);
93 if (aux == NULL) {
94 vfree(fp);
95 return NULL;
96 }
97
98 fp->pages = size / PAGE_SIZE;
99 fp->aux = aux;
100 fp->aux->prog = fp;
101 fp->jit_requested = ebpf_jit_enabled();
102
103 INIT_LIST_HEAD_RCU(&fp->aux->ksym_lnode);
104
105 return fp;
106 }
107
108 struct bpf_prog *bpf_prog_alloc(unsigned int size, gfp_t gfp_extra_flags)
109 {
110 gfp_t gfp_flags = GFP_KERNEL | __GFP_ZERO | gfp_extra_flags;
111 struct bpf_prog *prog;
112 int cpu;
113
114 prog = bpf_prog_alloc_no_stats(size, gfp_extra_flags);
115 if (!prog)
116 return NULL;
117
118 prog->aux->stats = alloc_percpu_gfp(struct bpf_prog_stats, gfp_flags);
119 if (!prog->aux->stats) {
120 kfree(prog->aux);
121 vfree(prog);
122 return NULL;
123 }
124
125 for_each_possible_cpu(cpu) {
126 struct bpf_prog_stats *pstats;
127
128 pstats = per_cpu_ptr(prog->aux->stats, cpu);
129 u64_stats_init(&pstats->syncp);
130 }
131 return prog;
132 }
133 EXPORT_SYMBOL_GPL(bpf_prog_alloc);
134
135 int bpf_prog_alloc_jited_linfo(struct bpf_prog *prog)
136 {
137 if (!prog->aux->nr_linfo || !prog->jit_requested)
138 return 0;
139
140 prog->aux->jited_linfo = kcalloc(prog->aux->nr_linfo,
141 sizeof(*prog->aux->jited_linfo),
142 GFP_KERNEL | __GFP_NOWARN);
143 if (!prog->aux->jited_linfo)
144 return -ENOMEM;
145
146 return 0;
147 }
148
149 void bpf_prog_free_jited_linfo(struct bpf_prog *prog)
150 {
151 kfree(prog->aux->jited_linfo);
152 prog->aux->jited_linfo = NULL;
153 }
154
155 void bpf_prog_free_unused_jited_linfo(struct bpf_prog *prog)
156 {
157 if (prog->aux->jited_linfo && !prog->aux->jited_linfo[0])
158 bpf_prog_free_jited_linfo(prog);
159 }
160
161 /* The jit engine is responsible to provide an array
162 * for insn_off to the jited_off mapping (insn_to_jit_off).
163 *
164 * The idx to this array is the insn_off. Hence, the insn_off
165 * here is relative to the prog itself instead of the main prog.
166 * This array has one entry for each xlated bpf insn.
167 *
168 * jited_off is the byte off to the last byte of the jited insn.
169 *
170 * Hence, with
171 * insn_start:
172 * The first bpf insn off of the prog. The insn off
173 * here is relative to the main prog.
174 * e.g. if prog is a subprog, insn_start > 0
175 * linfo_idx:
176 * The prog's idx to prog->aux->linfo and jited_linfo
177 *
178 * jited_linfo[linfo_idx] = prog->bpf_func
179 *
180 * For i > linfo_idx,
181 *
182 * jited_linfo[i] = prog->bpf_func +
183 * insn_to_jit_off[linfo[i].insn_off - insn_start - 1]
184 */
185 void bpf_prog_fill_jited_linfo(struct bpf_prog *prog,
186 const u32 *insn_to_jit_off)
187 {
188 u32 linfo_idx, insn_start, insn_end, nr_linfo, i;
189 const struct bpf_line_info *linfo;
190 void **jited_linfo;
191
192 if (!prog->aux->jited_linfo)
193 /* Userspace did not provide linfo */
194 return;
195
196 linfo_idx = prog->aux->linfo_idx;
197 linfo = &prog->aux->linfo[linfo_idx];
198 insn_start = linfo[0].insn_off;
199 insn_end = insn_start + prog->len;
200
201 jited_linfo = &prog->aux->jited_linfo[linfo_idx];
202 jited_linfo[0] = prog->bpf_func;
203
204 nr_linfo = prog->aux->nr_linfo - linfo_idx;
205
206 for (i = 1; i < nr_linfo && linfo[i].insn_off < insn_end; i++)
207 /* The verifier ensures that linfo[i].insn_off is
208 * strictly increasing
209 */
210 jited_linfo[i] = prog->bpf_func +
211 insn_to_jit_off[linfo[i].insn_off - insn_start - 1];
212 }
213
214 void bpf_prog_free_linfo(struct bpf_prog *prog)
215 {
216 bpf_prog_free_jited_linfo(prog);
217 kvfree(prog->aux->linfo);
218 }
219
220 struct bpf_prog *bpf_prog_realloc(struct bpf_prog *fp_old, unsigned int size,
221 gfp_t gfp_extra_flags)
222 {
223 gfp_t gfp_flags = GFP_KERNEL | __GFP_ZERO | gfp_extra_flags;
224 struct bpf_prog *fp;
225 u32 pages, delta;
226 int ret;
227
228 BUG_ON(fp_old == NULL);
229
230 size = round_up(size, PAGE_SIZE);
231 pages = size / PAGE_SIZE;
232 if (pages <= fp_old->pages)
233 return fp_old;
234
235 delta = pages - fp_old->pages;
236 ret = __bpf_prog_charge(fp_old->aux->user, delta);
237 if (ret)
238 return NULL;
239
240 fp = __vmalloc(size, gfp_flags, PAGE_KERNEL);
241 if (fp == NULL) {
242 __bpf_prog_uncharge(fp_old->aux->user, delta);
243 } else {
244 memcpy(fp, fp_old, fp_old->pages * PAGE_SIZE);
245 fp->pages = pages;
246 fp->aux->prog = fp;
247
248 /* We keep fp->aux from fp_old around in the new
249 * reallocated structure.
250 */
251 fp_old->aux = NULL;
252 __bpf_prog_free(fp_old);
253 }
254
255 return fp;
256 }
257
258 void __bpf_prog_free(struct bpf_prog *fp)
259 {
260 if (fp->aux) {
261 free_percpu(fp->aux->stats);
262 kfree(fp->aux);
263 }
264 vfree(fp);
265 }
266
267 int bpf_prog_calc_tag(struct bpf_prog *fp)
268 {
269 const u32 bits_offset = SHA_MESSAGE_BYTES - sizeof(__be64);
270 u32 raw_size = bpf_prog_tag_scratch_size(fp);
271 u32 digest[SHA_DIGEST_WORDS];
272 u32 ws[SHA_WORKSPACE_WORDS];
273 u32 i, bsize, psize, blocks;
274 struct bpf_insn *dst;
275 bool was_ld_map;
276 u8 *raw, *todo;
277 __be32 *result;
278 __be64 *bits;
279
280 raw = vmalloc(raw_size);
281 if (!raw)
282 return -ENOMEM;
283
284 sha_init(digest);
285 memset(ws, 0, sizeof(ws));
286
287 /* We need to take out the map fd for the digest calculation
288 * since they are unstable from user space side.
289 */
290 dst = (void *)raw;
291 for (i = 0, was_ld_map = false; i < fp->len; i++) {
292 dst[i] = fp->insnsi[i];
293 if (!was_ld_map &&
294 dst[i].code == (BPF_LD | BPF_IMM | BPF_DW) &&
295 dst[i].src_reg == BPF_PSEUDO_MAP_FD) {
296 was_ld_map = true;
297 dst[i].imm = 0;
298 } else if (was_ld_map &&
299 dst[i].code == 0 &&
300 dst[i].dst_reg == 0 &&
301 dst[i].src_reg == 0 &&
302 dst[i].off == 0) {
303 was_ld_map = false;
304 dst[i].imm = 0;
305 } else {
306 was_ld_map = false;
307 }
308 }
309
310 psize = bpf_prog_insn_size(fp);
311 memset(&raw[psize], 0, raw_size - psize);
312 raw[psize++] = 0x80;
313
314 bsize = round_up(psize, SHA_MESSAGE_BYTES);
315 blocks = bsize / SHA_MESSAGE_BYTES;
316 todo = raw;
317 if (bsize - psize >= sizeof(__be64)) {
318 bits = (__be64 *)(todo + bsize - sizeof(__be64));
319 } else {
320 bits = (__be64 *)(todo + bsize + bits_offset);
321 blocks++;
322 }
323 *bits = cpu_to_be64((psize - 1) << 3);
324
325 while (blocks--) {
326 sha_transform(digest, todo, ws);
327 todo += SHA_MESSAGE_BYTES;
328 }
329
330 result = (__force __be32 *)digest;
331 for (i = 0; i < SHA_DIGEST_WORDS; i++)
332 result[i] = cpu_to_be32(digest[i]);
333 memcpy(fp->tag, result, sizeof(fp->tag));
334
335 vfree(raw);
336 return 0;
337 }
338
339 static int bpf_adj_delta_to_imm(struct bpf_insn *insn, u32 pos, s32 end_old,
340 s32 end_new, u32 curr, const bool probe_pass)
341 {
342 const s64 imm_min = S32_MIN, imm_max = S32_MAX;
343 s32 delta = end_new - end_old;
344 s64 imm = insn->imm;
345
346 if (curr < pos && curr + imm + 1 >= end_old)
347 imm += delta;
348 else if (curr >= end_new && curr + imm + 1 < end_new)
349 imm -= delta;
350 if (imm < imm_min || imm > imm_max)
351 return -ERANGE;
352 if (!probe_pass)
353 insn->imm = imm;
354 return 0;
355 }
356
357 static int bpf_adj_delta_to_off(struct bpf_insn *insn, u32 pos, s32 end_old,
358 s32 end_new, u32 curr, const bool probe_pass)
359 {
360 const s32 off_min = S16_MIN, off_max = S16_MAX;
361 s32 delta = end_new - end_old;
362 s32 off = insn->off;
363
364 if (curr < pos && curr + off + 1 >= end_old)
365 off += delta;
366 else if (curr >= end_new && curr + off + 1 < end_new)
367 off -= delta;
368 if (off < off_min || off > off_max)
369 return -ERANGE;
370 if (!probe_pass)
371 insn->off = off;
372 return 0;
373 }
374
375 static int bpf_adj_branches(struct bpf_prog *prog, u32 pos, s32 end_old,
376 s32 end_new, const bool probe_pass)
377 {
378 u32 i, insn_cnt = prog->len + (probe_pass ? end_new - end_old : 0);
379 struct bpf_insn *insn = prog->insnsi;
380 int ret = 0;
381
382 for (i = 0; i < insn_cnt; i++, insn++) {
383 u8 code;
384
385 /* In the probing pass we still operate on the original,
386 * unpatched image in order to check overflows before we
387 * do any other adjustments. Therefore skip the patchlet.
388 */
389 if (probe_pass && i == pos) {
390 i = end_new;
391 insn = prog->insnsi + end_old;
392 }
393 code = insn->code;
394 if ((BPF_CLASS(code) != BPF_JMP &&
395 BPF_CLASS(code) != BPF_JMP32) ||
396 BPF_OP(code) == BPF_EXIT)
397 continue;
398 /* Adjust offset of jmps if we cross patch boundaries. */
399 if (BPF_OP(code) == BPF_CALL) {
400 if (insn->src_reg != BPF_PSEUDO_CALL)
401 continue;
402 ret = bpf_adj_delta_to_imm(insn, pos, end_old,
403 end_new, i, probe_pass);
404 } else {
405 ret = bpf_adj_delta_to_off(insn, pos, end_old,
406 end_new, i, probe_pass);
407 }
408 if (ret)
409 break;
410 }
411
412 return ret;
413 }
414
415 static void bpf_adj_linfo(struct bpf_prog *prog, u32 off, u32 delta)
416 {
417 struct bpf_line_info *linfo;
418 u32 i, nr_linfo;
419
420 nr_linfo = prog->aux->nr_linfo;
421 if (!nr_linfo || !delta)
422 return;
423
424 linfo = prog->aux->linfo;
425
426 for (i = 0; i < nr_linfo; i++)
427 if (off < linfo[i].insn_off)
428 break;
429
430 /* Push all off < linfo[i].insn_off by delta */
431 for (; i < nr_linfo; i++)
432 linfo[i].insn_off += delta;
433 }
434
435 struct bpf_prog *bpf_patch_insn_single(struct bpf_prog *prog, u32 off,
436 const struct bpf_insn *patch, u32 len)
437 {
438 u32 insn_adj_cnt, insn_rest, insn_delta = len - 1;
439 const u32 cnt_max = S16_MAX;
440 struct bpf_prog *prog_adj;
441
442 /* Since our patchlet doesn't expand the image, we're done. */
443 if (insn_delta == 0) {
444 memcpy(prog->insnsi + off, patch, sizeof(*patch));
445 return prog;
446 }
447
448 insn_adj_cnt = prog->len + insn_delta;
449
450 /* Reject anything that would potentially let the insn->off
451 * target overflow when we have excessive program expansions.
452 * We need to probe here before we do any reallocation where
453 * we afterwards may not fail anymore.
454 */
455 if (insn_adj_cnt > cnt_max &&
456 bpf_adj_branches(prog, off, off + 1, off + len, true))
457 return NULL;
458
459 /* Several new instructions need to be inserted. Make room
460 * for them. Likely, there's no need for a new allocation as
461 * last page could have large enough tailroom.
462 */
463 prog_adj = bpf_prog_realloc(prog, bpf_prog_size(insn_adj_cnt),
464 GFP_USER);
465 if (!prog_adj)
466 return NULL;
467
468 prog_adj->len = insn_adj_cnt;
469
470 /* Patching happens in 3 steps:
471 *
472 * 1) Move over tail of insnsi from next instruction onwards,
473 * so we can patch the single target insn with one or more
474 * new ones (patching is always from 1 to n insns, n > 0).
475 * 2) Inject new instructions at the target location.
476 * 3) Adjust branch offsets if necessary.
477 */
478 insn_rest = insn_adj_cnt - off - len;
479
480 memmove(prog_adj->insnsi + off + len, prog_adj->insnsi + off + 1,
481 sizeof(*patch) * insn_rest);
482 memcpy(prog_adj->insnsi + off, patch, sizeof(*patch) * len);
483
484 /* We are guaranteed to not fail at this point, otherwise
485 * the ship has sailed to reverse to the original state. An
486 * overflow cannot happen at this point.
487 */
488 BUG_ON(bpf_adj_branches(prog_adj, off, off + 1, off + len, false));
489
490 bpf_adj_linfo(prog_adj, off, insn_delta);
491
492 return prog_adj;
493 }
494
495 int bpf_remove_insns(struct bpf_prog *prog, u32 off, u32 cnt)
496 {
497 /* Branch offsets can't overflow when program is shrinking, no need
498 * to call bpf_adj_branches(..., true) here
499 */
500 memmove(prog->insnsi + off, prog->insnsi + off + cnt,
501 sizeof(struct bpf_insn) * (prog->len - off - cnt));
502 prog->len -= cnt;
503
504 return WARN_ON_ONCE(bpf_adj_branches(prog, off, off + cnt, off, false));
505 }
506
507 void bpf_prog_kallsyms_del_subprogs(struct bpf_prog *fp)
508 {
509 int i;
510
511 for (i = 0; i < fp->aux->func_cnt; i++)
512 bpf_prog_kallsyms_del(fp->aux->func[i]);
513 }
514
515 void bpf_prog_kallsyms_del_all(struct bpf_prog *fp)
516 {
517 bpf_prog_kallsyms_del_subprogs(fp);
518 bpf_prog_kallsyms_del(fp);
519 }
520
521 #ifdef CONFIG_BPF_JIT
522 /* All BPF JIT sysctl knobs here. */
523 int bpf_jit_enable __read_mostly = IS_BUILTIN(CONFIG_BPF_JIT_ALWAYS_ON);
524 int bpf_jit_harden __read_mostly;
525 int bpf_jit_kallsyms __read_mostly;
526 long bpf_jit_limit __read_mostly;
527
528 static __always_inline void
529 bpf_get_prog_addr_region(const struct bpf_prog *prog,
530 unsigned long *symbol_start,
531 unsigned long *symbol_end)
532 {
533 const struct bpf_binary_header *hdr = bpf_jit_binary_hdr(prog);
534 unsigned long addr = (unsigned long)hdr;
535
536 WARN_ON_ONCE(!bpf_prog_ebpf_jited(prog));
537
538 *symbol_start = addr;
539 *symbol_end = addr + hdr->pages * PAGE_SIZE;
540 }
541
542 void bpf_get_prog_name(const struct bpf_prog *prog, char *sym)
543 {
544 const char *end = sym + KSYM_NAME_LEN;
545 const struct btf_type *type;
546 const char *func_name;
547
548 BUILD_BUG_ON(sizeof("bpf_prog_") +
549 sizeof(prog->tag) * 2 +
550 /* name has been null terminated.
551 * We should need +1 for the '_' preceding
552 * the name. However, the null character
553 * is double counted between the name and the
554 * sizeof("bpf_prog_") above, so we omit
555 * the +1 here.
556 */
557 sizeof(prog->aux->name) > KSYM_NAME_LEN);
558
559 sym += snprintf(sym, KSYM_NAME_LEN, "bpf_prog_");
560 sym = bin2hex(sym, prog->tag, sizeof(prog->tag));
561
562 /* prog->aux->name will be ignored if full btf name is available */
563 if (prog->aux->func_info_cnt) {
564 type = btf_type_by_id(prog->aux->btf,
565 prog->aux->func_info[prog->aux->func_idx].type_id);
566 func_name = btf_name_by_offset(prog->aux->btf, type->name_off);
567 snprintf(sym, (size_t)(end - sym), "_%s", func_name);
568 return;
569 }
570
571 if (prog->aux->name[0])
572 snprintf(sym, (size_t)(end - sym), "_%s", prog->aux->name);
573 else
574 *sym = 0;
575 }
576
577 static __always_inline unsigned long
578 bpf_get_prog_addr_start(struct latch_tree_node *n)
579 {
580 unsigned long symbol_start, symbol_end;
581 const struct bpf_prog_aux *aux;
582
583 aux = container_of(n, struct bpf_prog_aux, ksym_tnode);
584 bpf_get_prog_addr_region(aux->prog, &symbol_start, &symbol_end);
585
586 return symbol_start;
587 }
588
589 static __always_inline bool bpf_tree_less(struct latch_tree_node *a,
590 struct latch_tree_node *b)
591 {
592 return bpf_get_prog_addr_start(a) < bpf_get_prog_addr_start(b);
593 }
594
595 static __always_inline int bpf_tree_comp(void *key, struct latch_tree_node *n)
596 {
597 unsigned long val = (unsigned long)key;
598 unsigned long symbol_start, symbol_end;
599 const struct bpf_prog_aux *aux;
600
601 aux = container_of(n, struct bpf_prog_aux, ksym_tnode);
602 bpf_get_prog_addr_region(aux->prog, &symbol_start, &symbol_end);
603
604 if (val < symbol_start)
605 return -1;
606 if (val >= symbol_end)
607 return 1;
608
609 return 0;
610 }
611
612 static const struct latch_tree_ops bpf_tree_ops = {
613 .less = bpf_tree_less,
614 .comp = bpf_tree_comp,
615 };
616
617 static DEFINE_SPINLOCK(bpf_lock);
618 static LIST_HEAD(bpf_kallsyms);
619 static struct latch_tree_root bpf_tree __cacheline_aligned;
620
621 static void bpf_prog_ksym_node_add(struct bpf_prog_aux *aux)
622 {
623 WARN_ON_ONCE(!list_empty(&aux->ksym_lnode));
624 list_add_tail_rcu(&aux->ksym_lnode, &bpf_kallsyms);
625 latch_tree_insert(&aux->ksym_tnode, &bpf_tree, &bpf_tree_ops);
626 }
627
628 static void bpf_prog_ksym_node_del(struct bpf_prog_aux *aux)
629 {
630 if (list_empty(&aux->ksym_lnode))
631 return;
632
633 latch_tree_erase(&aux->ksym_tnode, &bpf_tree, &bpf_tree_ops);
634 list_del_rcu(&aux->ksym_lnode);
635 }
636
637 static bool bpf_prog_kallsyms_candidate(const struct bpf_prog *fp)
638 {
639 return fp->jited && !bpf_prog_was_classic(fp);
640 }
641
642 static bool bpf_prog_kallsyms_verify_off(const struct bpf_prog *fp)
643 {
644 return list_empty(&fp->aux->ksym_lnode) ||
645 fp->aux->ksym_lnode.prev == LIST_POISON2;
646 }
647
648 void bpf_prog_kallsyms_add(struct bpf_prog *fp)
649 {
650 if (!bpf_prog_kallsyms_candidate(fp) ||
651 !capable(CAP_SYS_ADMIN))
652 return;
653
654 spin_lock_bh(&bpf_lock);
655 bpf_prog_ksym_node_add(fp->aux);
656 spin_unlock_bh(&bpf_lock);
657 }
658
659 void bpf_prog_kallsyms_del(struct bpf_prog *fp)
660 {
661 if (!bpf_prog_kallsyms_candidate(fp))
662 return;
663
664 spin_lock_bh(&bpf_lock);
665 bpf_prog_ksym_node_del(fp->aux);
666 spin_unlock_bh(&bpf_lock);
667 }
668
669 static struct bpf_prog *bpf_prog_kallsyms_find(unsigned long addr)
670 {
671 struct latch_tree_node *n;
672
673 if (!bpf_jit_kallsyms_enabled())
674 return NULL;
675
676 n = latch_tree_find((void *)addr, &bpf_tree, &bpf_tree_ops);
677 return n ?
678 container_of(n, struct bpf_prog_aux, ksym_tnode)->prog :
679 NULL;
680 }
681
682 const char *__bpf_address_lookup(unsigned long addr, unsigned long *size,
683 unsigned long *off, char *sym)
684 {
685 unsigned long symbol_start, symbol_end;
686 struct bpf_prog *prog;
687 char *ret = NULL;
688
689 rcu_read_lock();
690 prog = bpf_prog_kallsyms_find(addr);
691 if (prog) {
692 bpf_get_prog_addr_region(prog, &symbol_start, &symbol_end);
693 bpf_get_prog_name(prog, sym);
694
695 ret = sym;
696 if (size)
697 *size = symbol_end - symbol_start;
698 if (off)
699 *off = addr - symbol_start;
700 }
701 rcu_read_unlock();
702
703 return ret;
704 }
705
706 bool is_bpf_text_address(unsigned long addr)
707 {
708 bool ret;
709
710 rcu_read_lock();
711 ret = bpf_prog_kallsyms_find(addr) != NULL;
712 rcu_read_unlock();
713
714 return ret;
715 }
716
717 int bpf_get_kallsym(unsigned int symnum, unsigned long *value, char *type,
718 char *sym)
719 {
720 struct bpf_prog_aux *aux;
721 unsigned int it = 0;
722 int ret = -ERANGE;
723
724 if (!bpf_jit_kallsyms_enabled())
725 return ret;
726
727 rcu_read_lock();
728 list_for_each_entry_rcu(aux, &bpf_kallsyms, ksym_lnode) {
729 if (it++ != symnum)
730 continue;
731
732 bpf_get_prog_name(aux->prog, sym);
733
734 *value = (unsigned long)aux->prog->bpf_func;
735 *type = BPF_SYM_ELF_TYPE;
736
737 ret = 0;
738 break;
739 }
740 rcu_read_unlock();
741
742 return ret;
743 }
744
745 static atomic_long_t bpf_jit_current;
746
747 /* Can be overridden by an arch's JIT compiler if it has a custom,
748 * dedicated BPF backend memory area, or if neither of the two
749 * below apply.
750 */
751 u64 __weak bpf_jit_alloc_exec_limit(void)
752 {
753 #if defined(MODULES_VADDR)
754 return MODULES_END - MODULES_VADDR;
755 #else
756 return VMALLOC_END - VMALLOC_START;
757 #endif
758 }
759
760 static int __init bpf_jit_charge_init(void)
761 {
762 /* Only used as heuristic here to derive limit. */
763 bpf_jit_limit = min_t(u64, round_up(bpf_jit_alloc_exec_limit() >> 2,
764 PAGE_SIZE), LONG_MAX);
765 return 0;
766 }
767 pure_initcall(bpf_jit_charge_init);
768
769 static int bpf_jit_charge_modmem(u32 pages)
770 {
771 if (atomic_long_add_return(pages, &bpf_jit_current) >
772 (bpf_jit_limit >> PAGE_SHIFT)) {
773 if (!capable(CAP_SYS_ADMIN)) {
774 atomic_long_sub(pages, &bpf_jit_current);
775 return -EPERM;
776 }
777 }
778
779 return 0;
780 }
781
782 static void bpf_jit_uncharge_modmem(u32 pages)
783 {
784 atomic_long_sub(pages, &bpf_jit_current);
785 }
786
787 void *__weak bpf_jit_alloc_exec(unsigned long size)
788 {
789 return module_alloc(size);
790 }
791
792 void __weak bpf_jit_free_exec(void *addr)
793 {
794 module_memfree(addr);
795 }
796
797 struct bpf_binary_header *
798 bpf_jit_binary_alloc(unsigned int proglen, u8 **image_ptr,
799 unsigned int alignment,
800 bpf_jit_fill_hole_t bpf_fill_ill_insns)
801 {
802 struct bpf_binary_header *hdr;
803 u32 size, hole, start, pages;
804
805 /* Most of BPF filters are really small, but if some of them
806 * fill a page, allow at least 128 extra bytes to insert a
807 * random section of illegal instructions.
808 */
809 size = round_up(proglen + sizeof(*hdr) + 128, PAGE_SIZE);
810 pages = size / PAGE_SIZE;
811
812 if (bpf_jit_charge_modmem(pages))
813 return NULL;
814 hdr = bpf_jit_alloc_exec(size);
815 if (!hdr) {
816 bpf_jit_uncharge_modmem(pages);
817 return NULL;
818 }
819
820 /* Fill space with illegal/arch-dep instructions. */
821 bpf_fill_ill_insns(hdr, size);
822
823 hdr->pages = pages;
824 hole = min_t(unsigned int, size - (proglen + sizeof(*hdr)),
825 PAGE_SIZE - sizeof(*hdr));
826 start = (get_random_int() % hole) & ~(alignment - 1);
827
828 /* Leave a random number of instructions before BPF code. */
829 *image_ptr = &hdr->image[start];
830
831 return hdr;
832 }
833
834 void bpf_jit_binary_free(struct bpf_binary_header *hdr)
835 {
836 u32 pages = hdr->pages;
837
838 bpf_jit_free_exec(hdr);
839 bpf_jit_uncharge_modmem(pages);
840 }
841
842 /* This symbol is only overridden by archs that have different
843 * requirements than the usual eBPF JITs, f.e. when they only
844 * implement cBPF JIT, do not set images read-only, etc.
845 */
846 void __weak bpf_jit_free(struct bpf_prog *fp)
847 {
848 if (fp->jited) {
849 struct bpf_binary_header *hdr = bpf_jit_binary_hdr(fp);
850
851 bpf_jit_binary_unlock_ro(hdr);
852 bpf_jit_binary_free(hdr);
853
854 WARN_ON_ONCE(!bpf_prog_kallsyms_verify_off(fp));
855 }
856
857 bpf_prog_unlock_free(fp);
858 }
859
860 int bpf_jit_get_func_addr(const struct bpf_prog *prog,
861 const struct bpf_insn *insn, bool extra_pass,
862 u64 *func_addr, bool *func_addr_fixed)
863 {
864 s16 off = insn->off;
865 s32 imm = insn->imm;
866 u8 *addr;
867
868 *func_addr_fixed = insn->src_reg != BPF_PSEUDO_CALL;
869 if (!*func_addr_fixed) {
870 /* Place-holder address till the last pass has collected
871 * all addresses for JITed subprograms in which case we
872 * can pick them up from prog->aux.
873 */
874 if (!extra_pass)
875 addr = NULL;
876 else if (prog->aux->func &&
877 off >= 0 && off < prog->aux->func_cnt)
878 addr = (u8 *)prog->aux->func[off]->bpf_func;
879 else
880 return -EINVAL;
881 } else {
882 /* Address of a BPF helper call. Since part of the core
883 * kernel, it's always at a fixed location. __bpf_call_base
884 * and the helper with imm relative to it are both in core
885 * kernel.
886 */
887 addr = (u8 *)__bpf_call_base + imm;
888 }
889
890 *func_addr = (unsigned long)addr;
891 return 0;
892 }
893
894 static int bpf_jit_blind_insn(const struct bpf_insn *from,
895 const struct bpf_insn *aux,
896 struct bpf_insn *to_buff)
897 {
898 struct bpf_insn *to = to_buff;
899 u32 imm_rnd = get_random_int();
900 s16 off;
901
902 BUILD_BUG_ON(BPF_REG_AX + 1 != MAX_BPF_JIT_REG);
903 BUILD_BUG_ON(MAX_BPF_REG + 1 != MAX_BPF_JIT_REG);
904
905 /* Constraints on AX register:
906 *
907 * AX register is inaccessible from user space. It is mapped in
908 * all JITs, and used here for constant blinding rewrites. It is
909 * typically "stateless" meaning its contents are only valid within
910 * the executed instruction, but not across several instructions.
911 * There are a few exceptions however which are further detailed
912 * below.
913 *
914 * Constant blinding is only used by JITs, not in the interpreter.
915 * The interpreter uses AX in some occasions as a local temporary
916 * register e.g. in DIV or MOD instructions.
917 *
918 * In restricted circumstances, the verifier can also use the AX
919 * register for rewrites as long as they do not interfere with
920 * the above cases!
921 */
922 if (from->dst_reg == BPF_REG_AX || from->src_reg == BPF_REG_AX)
923 goto out;
924
925 if (from->imm == 0 &&
926 (from->code == (BPF_ALU | BPF_MOV | BPF_K) ||
927 from->code == (BPF_ALU64 | BPF_MOV | BPF_K))) {
928 *to++ = BPF_ALU64_REG(BPF_XOR, from->dst_reg, from->dst_reg);
929 goto out;
930 }
931
932 switch (from->code) {
933 case BPF_ALU | BPF_ADD | BPF_K:
934 case BPF_ALU | BPF_SUB | BPF_K:
935 case BPF_ALU | BPF_AND | BPF_K:
936 case BPF_ALU | BPF_OR | BPF_K:
937 case BPF_ALU | BPF_XOR | BPF_K:
938 case BPF_ALU | BPF_MUL | BPF_K:
939 case BPF_ALU | BPF_MOV | BPF_K:
940 case BPF_ALU | BPF_DIV | BPF_K:
941 case BPF_ALU | BPF_MOD | BPF_K:
942 *to++ = BPF_ALU32_IMM(BPF_MOV, BPF_REG_AX, imm_rnd ^ from->imm);
943 *to++ = BPF_ALU32_IMM(BPF_XOR, BPF_REG_AX, imm_rnd);
944 *to++ = BPF_ALU32_REG(from->code, from->dst_reg, BPF_REG_AX);
945 break;
946
947 case BPF_ALU64 | BPF_ADD | BPF_K:
948 case BPF_ALU64 | BPF_SUB | BPF_K:
949 case BPF_ALU64 | BPF_AND | BPF_K:
950 case BPF_ALU64 | BPF_OR | BPF_K:
951 case BPF_ALU64 | BPF_XOR | BPF_K:
952 case BPF_ALU64 | BPF_MUL | BPF_K:
953 case BPF_ALU64 | BPF_MOV | BPF_K:
954 case BPF_ALU64 | BPF_DIV | BPF_K:
955 case BPF_ALU64 | BPF_MOD | BPF_K:
956 *to++ = BPF_ALU64_IMM(BPF_MOV, BPF_REG_AX, imm_rnd ^ from->imm);
957 *to++ = BPF_ALU64_IMM(BPF_XOR, BPF_REG_AX, imm_rnd);
958 *to++ = BPF_ALU64_REG(from->code, from->dst_reg, BPF_REG_AX);
959 break;
960
961 case BPF_JMP | BPF_JEQ | BPF_K:
962 case BPF_JMP | BPF_JNE | BPF_K:
963 case BPF_JMP | BPF_JGT | BPF_K:
964 case BPF_JMP | BPF_JLT | BPF_K:
965 case BPF_JMP | BPF_JGE | BPF_K:
966 case BPF_JMP | BPF_JLE | BPF_K:
967 case BPF_JMP | BPF_JSGT | BPF_K:
968 case BPF_JMP | BPF_JSLT | BPF_K:
969 case BPF_JMP | BPF_JSGE | BPF_K:
970 case BPF_JMP | BPF_JSLE | BPF_K:
971 case BPF_JMP | BPF_JSET | BPF_K:
972 /* Accommodate for extra offset in case of a backjump. */
973 off = from->off;
974 if (off < 0)
975 off -= 2;
976 *to++ = BPF_ALU64_IMM(BPF_MOV, BPF_REG_AX, imm_rnd ^ from->imm);
977 *to++ = BPF_ALU64_IMM(BPF_XOR, BPF_REG_AX, imm_rnd);
978 *to++ = BPF_JMP_REG(from->code, from->dst_reg, BPF_REG_AX, off);
979 break;
980
981 case BPF_JMP32 | BPF_JEQ | BPF_K:
982 case BPF_JMP32 | BPF_JNE | BPF_K:
983 case BPF_JMP32 | BPF_JGT | BPF_K:
984 case BPF_JMP32 | BPF_JLT | BPF_K:
985 case BPF_JMP32 | BPF_JGE | BPF_K:
986 case BPF_JMP32 | BPF_JLE | BPF_K:
987 case BPF_JMP32 | BPF_JSGT | BPF_K:
988 case BPF_JMP32 | BPF_JSLT | BPF_K:
989 case BPF_JMP32 | BPF_JSGE | BPF_K:
990 case BPF_JMP32 | BPF_JSLE | BPF_K:
991 case BPF_JMP32 | BPF_JSET | BPF_K:
992 /* Accommodate for extra offset in case of a backjump. */
993 off = from->off;
994 if (off < 0)
995 off -= 2;
996 *to++ = BPF_ALU32_IMM(BPF_MOV, BPF_REG_AX, imm_rnd ^ from->imm);
997 *to++ = BPF_ALU32_IMM(BPF_XOR, BPF_REG_AX, imm_rnd);
998 *to++ = BPF_JMP32_REG(from->code, from->dst_reg, BPF_REG_AX,
999 off);
1000 break;
1001
1002 case BPF_LD | BPF_IMM | BPF_DW:
1003 *to++ = BPF_ALU64_IMM(BPF_MOV, BPF_REG_AX, imm_rnd ^ aux[1].imm);
1004 *to++ = BPF_ALU64_IMM(BPF_XOR, BPF_REG_AX, imm_rnd);
1005 *to++ = BPF_ALU64_IMM(BPF_LSH, BPF_REG_AX, 32);
1006 *to++ = BPF_ALU64_REG(BPF_MOV, aux[0].dst_reg, BPF_REG_AX);
1007 break;
1008 case 0: /* Part 2 of BPF_LD | BPF_IMM | BPF_DW. */
1009 *to++ = BPF_ALU32_IMM(BPF_MOV, BPF_REG_AX, imm_rnd ^ aux[0].imm);
1010 *to++ = BPF_ALU32_IMM(BPF_XOR, BPF_REG_AX, imm_rnd);
1011 *to++ = BPF_ALU64_REG(BPF_OR, aux[0].dst_reg, BPF_REG_AX);
1012 break;
1013
1014 case BPF_ST | BPF_MEM | BPF_DW:
1015 case BPF_ST | BPF_MEM | BPF_W:
1016 case BPF_ST | BPF_MEM | BPF_H:
1017 case BPF_ST | BPF_MEM | BPF_B:
1018 *to++ = BPF_ALU64_IMM(BPF_MOV, BPF_REG_AX, imm_rnd ^ from->imm);
1019 *to++ = BPF_ALU64_IMM(BPF_XOR, BPF_REG_AX, imm_rnd);
1020 *to++ = BPF_STX_MEM(from->code, from->dst_reg, BPF_REG_AX, from->off);
1021 break;
1022 }
1023 out:
1024 return to - to_buff;
1025 }
1026
1027 static struct bpf_prog *bpf_prog_clone_create(struct bpf_prog *fp_other,
1028 gfp_t gfp_extra_flags)
1029 {
1030 gfp_t gfp_flags = GFP_KERNEL | __GFP_ZERO | gfp_extra_flags;
1031 struct bpf_prog *fp;
1032
1033 fp = __vmalloc(fp_other->pages * PAGE_SIZE, gfp_flags, PAGE_KERNEL);
1034 if (fp != NULL) {
1035 /* aux->prog still points to the fp_other one, so
1036 * when promoting the clone to the real program,
1037 * this still needs to be adapted.
1038 */
1039 memcpy(fp, fp_other, fp_other->pages * PAGE_SIZE);
1040 }
1041
1042 return fp;
1043 }
1044
1045 static void bpf_prog_clone_free(struct bpf_prog *fp)
1046 {
1047 /* aux was stolen by the other clone, so we cannot free
1048 * it from this path! It will be freed eventually by the
1049 * other program on release.
1050 *
1051 * At this point, we don't need a deferred release since
1052 * clone is guaranteed to not be locked.
1053 */
1054 fp->aux = NULL;
1055 __bpf_prog_free(fp);
1056 }
1057
1058 void bpf_jit_prog_release_other(struct bpf_prog *fp, struct bpf_prog *fp_other)
1059 {
1060 /* We have to repoint aux->prog to self, as we don't
1061 * know whether fp here is the clone or the original.
1062 */
1063 fp->aux->prog = fp;
1064 bpf_prog_clone_free(fp_other);
1065 }
1066
1067 struct bpf_prog *bpf_jit_blind_constants(struct bpf_prog *prog)
1068 {
1069 struct bpf_insn insn_buff[16], aux[2];
1070 struct bpf_prog *clone, *tmp;
1071 int insn_delta, insn_cnt;
1072 struct bpf_insn *insn;
1073 int i, rewritten;
1074
1075 if (!bpf_jit_blinding_enabled(prog) || prog->blinded)
1076 return prog;
1077
1078 clone = bpf_prog_clone_create(prog, GFP_USER);
1079 if (!clone)
1080 return ERR_PTR(-ENOMEM);
1081
1082 insn_cnt = clone->len;
1083 insn = clone->insnsi;
1084
1085 for (i = 0; i < insn_cnt; i++, insn++) {
1086 /* We temporarily need to hold the original ld64 insn
1087 * so that we can still access the first part in the
1088 * second blinding run.
1089 */
1090 if (insn[0].code == (BPF_LD | BPF_IMM | BPF_DW) &&
1091 insn[1].code == 0)
1092 memcpy(aux, insn, sizeof(aux));
1093
1094 rewritten = bpf_jit_blind_insn(insn, aux, insn_buff);
1095 if (!rewritten)
1096 continue;
1097
1098 tmp = bpf_patch_insn_single(clone, i, insn_buff, rewritten);
1099 if (!tmp) {
1100 /* Patching may have repointed aux->prog during
1101 * realloc from the original one, so we need to
1102 * fix it up here on error.
1103 */
1104 bpf_jit_prog_release_other(prog, clone);
1105 return ERR_PTR(-ENOMEM);
1106 }
1107
1108 clone = tmp;
1109 insn_delta = rewritten - 1;
1110
1111 /* Walk new program and skip insns we just inserted. */
1112 insn = clone->insnsi + i + insn_delta;
1113 insn_cnt += insn_delta;
1114 i += insn_delta;
1115 }
1116
1117 clone->blinded = 1;
1118 return clone;
1119 }
1120 #endif /* CONFIG_BPF_JIT */
1121
1122 /* Base function for offset calculation. Needs to go into .text section,
1123 * therefore keeping it non-static as well; will also be used by JITs
1124 * anyway later on, so do not let the compiler omit it. This also needs
1125 * to go into kallsyms for correlation from e.g. bpftool, so naming
1126 * must not change.
1127 */
1128 noinline u64 __bpf_call_base(u64 r1, u64 r2, u64 r3, u64 r4, u64 r5)
1129 {
1130 return 0;
1131 }
1132 EXPORT_SYMBOL_GPL(__bpf_call_base);
1133
1134 /* All UAPI available opcodes. */
1135 #define BPF_INSN_MAP(INSN_2, INSN_3) \
1136 /* 32 bit ALU operations. */ \
1137 /* Register based. */ \
1138 INSN_3(ALU, ADD, X), \
1139 INSN_3(ALU, SUB, X), \
1140 INSN_3(ALU, AND, X), \
1141 INSN_3(ALU, OR, X), \
1142 INSN_3(ALU, LSH, X), \
1143 INSN_3(ALU, RSH, X), \
1144 INSN_3(ALU, XOR, X), \
1145 INSN_3(ALU, MUL, X), \
1146 INSN_3(ALU, MOV, X), \
1147 INSN_3(ALU, ARSH, X), \
1148 INSN_3(ALU, DIV, X), \
1149 INSN_3(ALU, MOD, X), \
1150 INSN_2(ALU, NEG), \
1151 INSN_3(ALU, END, TO_BE), \
1152 INSN_3(ALU, END, TO_LE), \
1153 /* Immediate based. */ \
1154 INSN_3(ALU, ADD, K), \
1155 INSN_3(ALU, SUB, K), \
1156 INSN_3(ALU, AND, K), \
1157 INSN_3(ALU, OR, K), \
1158 INSN_3(ALU, LSH, K), \
1159 INSN_3(ALU, RSH, K), \
1160 INSN_3(ALU, XOR, K), \
1161 INSN_3(ALU, MUL, K), \
1162 INSN_3(ALU, MOV, K), \
1163 INSN_3(ALU, ARSH, K), \
1164 INSN_3(ALU, DIV, K), \
1165 INSN_3(ALU, MOD, K), \
1166 /* 64 bit ALU operations. */ \
1167 /* Register based. */ \
1168 INSN_3(ALU64, ADD, X), \
1169 INSN_3(ALU64, SUB, X), \
1170 INSN_3(ALU64, AND, X), \
1171 INSN_3(ALU64, OR, X), \
1172 INSN_3(ALU64, LSH, X), \
1173 INSN_3(ALU64, RSH, X), \
1174 INSN_3(ALU64, XOR, X), \
1175 INSN_3(ALU64, MUL, X), \
1176 INSN_3(ALU64, MOV, X), \
1177 INSN_3(ALU64, ARSH, X), \
1178 INSN_3(ALU64, DIV, X), \
1179 INSN_3(ALU64, MOD, X), \
1180 INSN_2(ALU64, NEG), \
1181 /* Immediate based. */ \
1182 INSN_3(ALU64, ADD, K), \
1183 INSN_3(ALU64, SUB, K), \
1184 INSN_3(ALU64, AND, K), \
1185 INSN_3(ALU64, OR, K), \
1186 INSN_3(ALU64, LSH, K), \
1187 INSN_3(ALU64, RSH, K), \
1188 INSN_3(ALU64, XOR, K), \
1189 INSN_3(ALU64, MUL, K), \
1190 INSN_3(ALU64, MOV, K), \
1191 INSN_3(ALU64, ARSH, K), \
1192 INSN_3(ALU64, DIV, K), \
1193 INSN_3(ALU64, MOD, K), \
1194 /* Call instruction. */ \
1195 INSN_2(JMP, CALL), \
1196 /* Exit instruction. */ \
1197 INSN_2(JMP, EXIT), \
1198 /* 32-bit Jump instructions. */ \
1199 /* Register based. */ \
1200 INSN_3(JMP32, JEQ, X), \
1201 INSN_3(JMP32, JNE, X), \
1202 INSN_3(JMP32, JGT, X), \
1203 INSN_3(JMP32, JLT, X), \
1204 INSN_3(JMP32, JGE, X), \
1205 INSN_3(JMP32, JLE, X), \
1206 INSN_3(JMP32, JSGT, X), \
1207 INSN_3(JMP32, JSLT, X), \
1208 INSN_3(JMP32, JSGE, X), \
1209 INSN_3(JMP32, JSLE, X), \
1210 INSN_3(JMP32, JSET, X), \
1211 /* Immediate based. */ \
1212 INSN_3(JMP32, JEQ, K), \
1213 INSN_3(JMP32, JNE, K), \
1214 INSN_3(JMP32, JGT, K), \
1215 INSN_3(JMP32, JLT, K), \
1216 INSN_3(JMP32, JGE, K), \
1217 INSN_3(JMP32, JLE, K), \
1218 INSN_3(JMP32, JSGT, K), \
1219 INSN_3(JMP32, JSLT, K), \
1220 INSN_3(JMP32, JSGE, K), \
1221 INSN_3(JMP32, JSLE, K), \
1222 INSN_3(JMP32, JSET, K), \
1223 /* Jump instructions. */ \
1224 /* Register based. */ \
1225 INSN_3(JMP, JEQ, X), \
1226 INSN_3(JMP, JNE, X), \
1227 INSN_3(JMP, JGT, X), \
1228 INSN_3(JMP, JLT, X), \
1229 INSN_3(JMP, JGE, X), \
1230 INSN_3(JMP, JLE, X), \
1231 INSN_3(JMP, JSGT, X), \
1232 INSN_3(JMP, JSLT, X), \
1233 INSN_3(JMP, JSGE, X), \
1234 INSN_3(JMP, JSLE, X), \
1235 INSN_3(JMP, JSET, X), \
1236 /* Immediate based. */ \
1237 INSN_3(JMP, JEQ, K), \
1238 INSN_3(JMP, JNE, K), \
1239 INSN_3(JMP, JGT, K), \
1240 INSN_3(JMP, JLT, K), \
1241 INSN_3(JMP, JGE, K), \
1242 INSN_3(JMP, JLE, K), \
1243 INSN_3(JMP, JSGT, K), \
1244 INSN_3(JMP, JSLT, K), \
1245 INSN_3(JMP, JSGE, K), \
1246 INSN_3(JMP, JSLE, K), \
1247 INSN_3(JMP, JSET, K), \
1248 INSN_2(JMP, JA), \
1249 /* Store instructions. */ \
1250 /* Register based. */ \
1251 INSN_3(STX, MEM, B), \
1252 INSN_3(STX, MEM, H), \
1253 INSN_3(STX, MEM, W), \
1254 INSN_3(STX, MEM, DW), \
1255 INSN_3(STX, XADD, W), \
1256 INSN_3(STX, XADD, DW), \
1257 /* Immediate based. */ \
1258 INSN_3(ST, MEM, B), \
1259 INSN_3(ST, MEM, H), \
1260 INSN_3(ST, MEM, W), \
1261 INSN_3(ST, MEM, DW), \
1262 /* Load instructions. */ \
1263 /* Register based. */ \
1264 INSN_3(LDX, MEM, B), \
1265 INSN_3(LDX, MEM, H), \
1266 INSN_3(LDX, MEM, W), \
1267 INSN_3(LDX, MEM, DW), \
1268 /* Immediate based. */ \
1269 INSN_3(LD, IMM, DW)
1270
1271 bool bpf_opcode_in_insntable(u8 code)
1272 {
1273 #define BPF_INSN_2_TBL(x, y) [BPF_##x | BPF_##y] = true
1274 #define BPF_INSN_3_TBL(x, y, z) [BPF_##x | BPF_##y | BPF_##z] = true
1275 static const bool public_insntable[256] = {
1276 [0 ... 255] = false,
1277 /* Now overwrite non-defaults ... */
1278 BPF_INSN_MAP(BPF_INSN_2_TBL, BPF_INSN_3_TBL),
1279 /* UAPI exposed, but rewritten opcodes. cBPF carry-over. */
1280 [BPF_LD | BPF_ABS | BPF_B] = true,
1281 [BPF_LD | BPF_ABS | BPF_H] = true,
1282 [BPF_LD | BPF_ABS | BPF_W] = true,
1283 [BPF_LD | BPF_IND | BPF_B] = true,
1284 [BPF_LD | BPF_IND | BPF_H] = true,
1285 [BPF_LD | BPF_IND | BPF_W] = true,
1286 };
1287 #undef BPF_INSN_3_TBL
1288 #undef BPF_INSN_2_TBL
1289 return public_insntable[code];
1290 }
1291
1292 #ifndef CONFIG_BPF_JIT_ALWAYS_ON
1293 /**
1294 * __bpf_prog_run - run eBPF program on a given context
1295 * @regs: is the array of MAX_BPF_EXT_REG eBPF pseudo-registers
1296 * @insn: is the array of eBPF instructions
1297 * @stack: is the eBPF storage stack
1298 *
1299 * Decode and execute eBPF instructions.
1300 */
1301 static u64 ___bpf_prog_run(u64 *regs, const struct bpf_insn *insn, u64 *stack)
1302 {
1303 #define BPF_INSN_2_LBL(x, y) [BPF_##x | BPF_##y] = &&x##_##y
1304 #define BPF_INSN_3_LBL(x, y, z) [BPF_##x | BPF_##y | BPF_##z] = &&x##_##y##_##z
1305 static const void *jumptable[256] = {
1306 [0 ... 255] = &&default_label,
1307 /* Now overwrite non-defaults ... */
1308 BPF_INSN_MAP(BPF_INSN_2_LBL, BPF_INSN_3_LBL),
1309 /* Non-UAPI available opcodes. */
1310 [BPF_JMP | BPF_CALL_ARGS] = &&JMP_CALL_ARGS,
1311 [BPF_JMP | BPF_TAIL_CALL] = &&JMP_TAIL_CALL,
1312 };
1313 #undef BPF_INSN_3_LBL
1314 #undef BPF_INSN_2_LBL
1315 u32 tail_call_cnt = 0;
1316
1317 #define CONT ({ insn++; goto select_insn; })
1318 #define CONT_JMP ({ insn++; goto select_insn; })
1319
1320 select_insn:
1321 goto *jumptable[insn->code];
1322
1323 /* ALU */
1324 #define ALU(OPCODE, OP) \
1325 ALU64_##OPCODE##_X: \
1326 DST = DST OP SRC; \
1327 CONT; \
1328 ALU_##OPCODE##_X: \
1329 DST = (u32) DST OP (u32) SRC; \
1330 CONT; \
1331 ALU64_##OPCODE##_K: \
1332 DST = DST OP IMM; \
1333 CONT; \
1334 ALU_##OPCODE##_K: \
1335 DST = (u32) DST OP (u32) IMM; \
1336 CONT;
1337
1338 ALU(ADD, +)
1339 ALU(SUB, -)
1340 ALU(AND, &)
1341 ALU(OR, |)
1342 ALU(LSH, <<)
1343 ALU(RSH, >>)
1344 ALU(XOR, ^)
1345 ALU(MUL, *)
1346 #undef ALU
1347 ALU_NEG:
1348 DST = (u32) -DST;
1349 CONT;
1350 ALU64_NEG:
1351 DST = -DST;
1352 CONT;
1353 ALU_MOV_X:
1354 DST = (u32) SRC;
1355 CONT;
1356 ALU_MOV_K:
1357 DST = (u32) IMM;
1358 CONT;
1359 ALU64_MOV_X:
1360 DST = SRC;
1361 CONT;
1362 ALU64_MOV_K:
1363 DST = IMM;
1364 CONT;
1365 LD_IMM_DW:
1366 DST = (u64) (u32) insn[0].imm | ((u64) (u32) insn[1].imm) << 32;
1367 insn++;
1368 CONT;
1369 ALU_ARSH_X:
1370 DST = (u64) (u32) ((*(s32 *) &DST) >> SRC);
1371 CONT;
1372 ALU_ARSH_K:
1373 DST = (u64) (u32) ((*(s32 *) &DST) >> IMM);
1374 CONT;
1375 ALU64_ARSH_X:
1376 (*(s64 *) &DST) >>= SRC;
1377 CONT;
1378 ALU64_ARSH_K:
1379 (*(s64 *) &DST) >>= IMM;
1380 CONT;
1381 ALU64_MOD_X:
1382 div64_u64_rem(DST, SRC, &AX);
1383 DST = AX;
1384 CONT;
1385 ALU_MOD_X:
1386 AX = (u32) DST;
1387 DST = do_div(AX, (u32) SRC);
1388 CONT;
1389 ALU64_MOD_K:
1390 div64_u64_rem(DST, IMM, &AX);
1391 DST = AX;
1392 CONT;
1393 ALU_MOD_K:
1394 AX = (u32) DST;
1395 DST = do_div(AX, (u32) IMM);
1396 CONT;
1397 ALU64_DIV_X:
1398 DST = div64_u64(DST, SRC);
1399 CONT;
1400 ALU_DIV_X:
1401 AX = (u32) DST;
1402 do_div(AX, (u32) SRC);
1403 DST = (u32) AX;
1404 CONT;
1405 ALU64_DIV_K:
1406 DST = div64_u64(DST, IMM);
1407 CONT;
1408 ALU_DIV_K:
1409 AX = (u32) DST;
1410 do_div(AX, (u32) IMM);
1411 DST = (u32) AX;
1412 CONT;
1413 ALU_END_TO_BE:
1414 switch (IMM) {
1415 case 16:
1416 DST = (__force u16) cpu_to_be16(DST);
1417 break;
1418 case 32:
1419 DST = (__force u32) cpu_to_be32(DST);
1420 break;
1421 case 64:
1422 DST = (__force u64) cpu_to_be64(DST);
1423 break;
1424 }
1425 CONT;
1426 ALU_END_TO_LE:
1427 switch (IMM) {
1428 case 16:
1429 DST = (__force u16) cpu_to_le16(DST);
1430 break;
1431 case 32:
1432 DST = (__force u32) cpu_to_le32(DST);
1433 break;
1434 case 64:
1435 DST = (__force u64) cpu_to_le64(DST);
1436 break;
1437 }
1438 CONT;
1439
1440 /* CALL */
1441 JMP_CALL:
1442 /* Function call scratches BPF_R1-BPF_R5 registers,
1443 * preserves BPF_R6-BPF_R9, and stores return value
1444 * into BPF_R0.
1445 */
1446 BPF_R0 = (__bpf_call_base + insn->imm)(BPF_R1, BPF_R2, BPF_R3,
1447 BPF_R4, BPF_R5);
1448 CONT;
1449
1450 JMP_CALL_ARGS:
1451 BPF_R0 = (__bpf_call_base_args + insn->imm)(BPF_R1, BPF_R2,
1452 BPF_R3, BPF_R4,
1453 BPF_R5,
1454 insn + insn->off + 1);
1455 CONT;
1456
1457 JMP_TAIL_CALL: {
1458 struct bpf_map *map = (struct bpf_map *) (unsigned long) BPF_R2;
1459 struct bpf_array *array = container_of(map, struct bpf_array, map);
1460 struct bpf_prog *prog;
1461 u32 index = BPF_R3;
1462
1463 if (unlikely(index >= array->map.max_entries))
1464 goto out;
1465 if (unlikely(tail_call_cnt > MAX_TAIL_CALL_CNT))
1466 goto out;
1467
1468 tail_call_cnt++;
1469
1470 prog = READ_ONCE(array->ptrs[index]);
1471 if (!prog)
1472 goto out;
1473
1474 /* ARG1 at this point is guaranteed to point to CTX from
1475 * the verifier side due to the fact that the tail call is
1476 * handeled like a helper, that is, bpf_tail_call_proto,
1477 * where arg1_type is ARG_PTR_TO_CTX.
1478 */
1479 insn = prog->insnsi;
1480 goto select_insn;
1481 out:
1482 CONT;
1483 }
1484 JMP_JA:
1485 insn += insn->off;
1486 CONT;
1487 JMP_EXIT:
1488 return BPF_R0;
1489 /* JMP */
1490 #define COND_JMP(SIGN, OPCODE, CMP_OP) \
1491 JMP_##OPCODE##_X: \
1492 if ((SIGN##64) DST CMP_OP (SIGN##64) SRC) { \
1493 insn += insn->off; \
1494 CONT_JMP; \
1495 } \
1496 CONT; \
1497 JMP32_##OPCODE##_X: \
1498 if ((SIGN##32) DST CMP_OP (SIGN##32) SRC) { \
1499 insn += insn->off; \
1500 CONT_JMP; \
1501 } \
1502 CONT; \
1503 JMP_##OPCODE##_K: \
1504 if ((SIGN##64) DST CMP_OP (SIGN##64) IMM) { \
1505 insn += insn->off; \
1506 CONT_JMP; \
1507 } \
1508 CONT; \
1509 JMP32_##OPCODE##_K: \
1510 if ((SIGN##32) DST CMP_OP (SIGN##32) IMM) { \
1511 insn += insn->off; \
1512 CONT_JMP; \
1513 } \
1514 CONT;
1515 COND_JMP(u, JEQ, ==)
1516 COND_JMP(u, JNE, !=)
1517 COND_JMP(u, JGT, >)
1518 COND_JMP(u, JLT, <)
1519 COND_JMP(u, JGE, >=)
1520 COND_JMP(u, JLE, <=)
1521 COND_JMP(u, JSET, &)
1522 COND_JMP(s, JSGT, >)
1523 COND_JMP(s, JSLT, <)
1524 COND_JMP(s, JSGE, >=)
1525 COND_JMP(s, JSLE, <=)
1526 #undef COND_JMP
1527 /* STX and ST and LDX*/
1528 #define LDST(SIZEOP, SIZE) \
1529 STX_MEM_##SIZEOP: \
1530 *(SIZE *)(unsigned long) (DST + insn->off) = SRC; \
1531 CONT; \
1532 ST_MEM_##SIZEOP: \
1533 *(SIZE *)(unsigned long) (DST + insn->off) = IMM; \
1534 CONT; \
1535 LDX_MEM_##SIZEOP: \
1536 DST = *(SIZE *)(unsigned long) (SRC + insn->off); \
1537 CONT;
1538
1539 LDST(B, u8)
1540 LDST(H, u16)
1541 LDST(W, u32)
1542 LDST(DW, u64)
1543 #undef LDST
1544 STX_XADD_W: /* lock xadd *(u32 *)(dst_reg + off16) += src_reg */
1545 atomic_add((u32) SRC, (atomic_t *)(unsigned long)
1546 (DST + insn->off));
1547 CONT;
1548 STX_XADD_DW: /* lock xadd *(u64 *)(dst_reg + off16) += src_reg */
1549 atomic64_add((u64) SRC, (atomic64_t *)(unsigned long)
1550 (DST + insn->off));
1551 CONT;
1552
1553 default_label:
1554 /* If we ever reach this, we have a bug somewhere. Die hard here
1555 * instead of just returning 0; we could be somewhere in a subprog,
1556 * so execution could continue otherwise which we do /not/ want.
1557 *
1558 * Note, verifier whitelists all opcodes in bpf_opcode_in_insntable().
1559 */
1560 pr_warn("BPF interpreter: unknown opcode %02x\n", insn->code);
1561 BUG_ON(1);
1562 return 0;
1563 }
1564 STACK_FRAME_NON_STANDARD(___bpf_prog_run); /* jump table */
1565
1566 #define PROG_NAME(stack_size) __bpf_prog_run##stack_size
1567 #define DEFINE_BPF_PROG_RUN(stack_size) \
1568 static unsigned int PROG_NAME(stack_size)(const void *ctx, const struct bpf_insn *insn) \
1569 { \
1570 u64 stack[stack_size / sizeof(u64)]; \
1571 u64 regs[MAX_BPF_EXT_REG]; \
1572 \
1573 FP = (u64) (unsigned long) &stack[ARRAY_SIZE(stack)]; \
1574 ARG1 = (u64) (unsigned long) ctx; \
1575 return ___bpf_prog_run(regs, insn, stack); \
1576 }
1577
1578 #define PROG_NAME_ARGS(stack_size) __bpf_prog_run_args##stack_size
1579 #define DEFINE_BPF_PROG_RUN_ARGS(stack_size) \
1580 static u64 PROG_NAME_ARGS(stack_size)(u64 r1, u64 r2, u64 r3, u64 r4, u64 r5, \
1581 const struct bpf_insn *insn) \
1582 { \
1583 u64 stack[stack_size / sizeof(u64)]; \
1584 u64 regs[MAX_BPF_EXT_REG]; \
1585 \
1586 FP = (u64) (unsigned long) &stack[ARRAY_SIZE(stack)]; \
1587 BPF_R1 = r1; \
1588 BPF_R2 = r2; \
1589 BPF_R3 = r3; \
1590 BPF_R4 = r4; \
1591 BPF_R5 = r5; \
1592 return ___bpf_prog_run(regs, insn, stack); \
1593 }
1594
1595 #define EVAL1(FN, X) FN(X)
1596 #define EVAL2(FN, X, Y...) FN(X) EVAL1(FN, Y)
1597 #define EVAL3(FN, X, Y...) FN(X) EVAL2(FN, Y)
1598 #define EVAL4(FN, X, Y...) FN(X) EVAL3(FN, Y)
1599 #define EVAL5(FN, X, Y...) FN(X) EVAL4(FN, Y)
1600 #define EVAL6(FN, X, Y...) FN(X) EVAL5(FN, Y)
1601
1602 EVAL6(DEFINE_BPF_PROG_RUN, 32, 64, 96, 128, 160, 192);
1603 EVAL6(DEFINE_BPF_PROG_RUN, 224, 256, 288, 320, 352, 384);
1604 EVAL4(DEFINE_BPF_PROG_RUN, 416, 448, 480, 512);
1605
1606 EVAL6(DEFINE_BPF_PROG_RUN_ARGS, 32, 64, 96, 128, 160, 192);
1607 EVAL6(DEFINE_BPF_PROG_RUN_ARGS, 224, 256, 288, 320, 352, 384);
1608 EVAL4(DEFINE_BPF_PROG_RUN_ARGS, 416, 448, 480, 512);
1609
1610 #define PROG_NAME_LIST(stack_size) PROG_NAME(stack_size),
1611
1612 static unsigned int (*interpreters[])(const void *ctx,
1613 const struct bpf_insn *insn) = {
1614 EVAL6(PROG_NAME_LIST, 32, 64, 96, 128, 160, 192)
1615 EVAL6(PROG_NAME_LIST, 224, 256, 288, 320, 352, 384)
1616 EVAL4(PROG_NAME_LIST, 416, 448, 480, 512)
1617 };
1618 #undef PROG_NAME_LIST
1619 #define PROG_NAME_LIST(stack_size) PROG_NAME_ARGS(stack_size),
1620 static u64 (*interpreters_args[])(u64 r1, u64 r2, u64 r3, u64 r4, u64 r5,
1621 const struct bpf_insn *insn) = {
1622 EVAL6(PROG_NAME_LIST, 32, 64, 96, 128, 160, 192)
1623 EVAL6(PROG_NAME_LIST, 224, 256, 288, 320, 352, 384)
1624 EVAL4(PROG_NAME_LIST, 416, 448, 480, 512)
1625 };
1626 #undef PROG_NAME_LIST
1627
1628 void bpf_patch_call_args(struct bpf_insn *insn, u32 stack_depth)
1629 {
1630 stack_depth = max_t(u32, stack_depth, 1);
1631 insn->off = (s16) insn->imm;
1632 insn->imm = interpreters_args[(round_up(stack_depth, 32) / 32) - 1] -
1633 __bpf_call_base_args;
1634 insn->code = BPF_JMP | BPF_CALL_ARGS;
1635 }
1636
1637 #else
1638 static unsigned int __bpf_prog_ret0_warn(const void *ctx,
1639 const struct bpf_insn *insn)
1640 {
1641 /* If this handler ever gets executed, then BPF_JIT_ALWAYS_ON
1642 * is not working properly, so warn about it!
1643 */
1644 WARN_ON_ONCE(1);
1645 return 0;
1646 }
1647 #endif
1648
1649 bool bpf_prog_array_compatible(struct bpf_array *array,
1650 const struct bpf_prog *fp)
1651 {
1652 if (fp->kprobe_override)
1653 return false;
1654
1655 if (!array->owner_prog_type) {
1656 /* There's no owner yet where we could check for
1657 * compatibility.
1658 */
1659 array->owner_prog_type = fp->type;
1660 array->owner_jited = fp->jited;
1661
1662 return true;
1663 }
1664
1665 return array->owner_prog_type == fp->type &&
1666 array->owner_jited == fp->jited;
1667 }
1668
1669 static int bpf_check_tail_call(const struct bpf_prog *fp)
1670 {
1671 struct bpf_prog_aux *aux = fp->aux;
1672 int i;
1673
1674 for (i = 0; i < aux->used_map_cnt; i++) {
1675 struct bpf_map *map = aux->used_maps[i];
1676 struct bpf_array *array;
1677
1678 if (map->map_type != BPF_MAP_TYPE_PROG_ARRAY)
1679 continue;
1680
1681 array = container_of(map, struct bpf_array, map);
1682 if (!bpf_prog_array_compatible(array, fp))
1683 return -EINVAL;
1684 }
1685
1686 return 0;
1687 }
1688
1689 static void bpf_prog_select_func(struct bpf_prog *fp)
1690 {
1691 #ifndef CONFIG_BPF_JIT_ALWAYS_ON
1692 u32 stack_depth = max_t(u32, fp->aux->stack_depth, 1);
1693
1694 fp->bpf_func = interpreters[(round_up(stack_depth, 32) / 32) - 1];
1695 #else
1696 fp->bpf_func = __bpf_prog_ret0_warn;
1697 #endif
1698 }
1699
1700 /**
1701 * bpf_prog_select_runtime - select exec runtime for BPF program
1702 * @fp: bpf_prog populated with internal BPF program
1703 * @err: pointer to error variable
1704 *
1705 * Try to JIT eBPF program, if JIT is not available, use interpreter.
1706 * The BPF program will be executed via BPF_PROG_RUN() macro.
1707 */
1708 struct bpf_prog *bpf_prog_select_runtime(struct bpf_prog *fp, int *err)
1709 {
1710 /* In case of BPF to BPF calls, verifier did all the prep
1711 * work with regards to JITing, etc.
1712 */
1713 if (fp->bpf_func)
1714 goto finalize;
1715
1716 bpf_prog_select_func(fp);
1717
1718 /* eBPF JITs can rewrite the program in case constant
1719 * blinding is active. However, in case of error during
1720 * blinding, bpf_int_jit_compile() must always return a
1721 * valid program, which in this case would simply not
1722 * be JITed, but falls back to the interpreter.
1723 */
1724 if (!bpf_prog_is_dev_bound(fp->aux)) {
1725 *err = bpf_prog_alloc_jited_linfo(fp);
1726 if (*err)
1727 return fp;
1728
1729 fp = bpf_int_jit_compile(fp);
1730 if (!fp->jited) {
1731 bpf_prog_free_jited_linfo(fp);
1732 #ifdef CONFIG_BPF_JIT_ALWAYS_ON
1733 *err = -ENOTSUPP;
1734 return fp;
1735 #endif
1736 } else {
1737 bpf_prog_free_unused_jited_linfo(fp);
1738 }
1739 } else {
1740 *err = bpf_prog_offload_compile(fp);
1741 if (*err)
1742 return fp;
1743 }
1744
1745 finalize:
1746 bpf_prog_lock_ro(fp);
1747
1748 /* The tail call compatibility check can only be done at
1749 * this late stage as we need to determine, if we deal
1750 * with JITed or non JITed program concatenations and not
1751 * all eBPF JITs might immediately support all features.
1752 */
1753 *err = bpf_check_tail_call(fp);
1754
1755 return fp;
1756 }
1757 EXPORT_SYMBOL_GPL(bpf_prog_select_runtime);
1758
1759 static unsigned int __bpf_prog_ret1(const void *ctx,
1760 const struct bpf_insn *insn)
1761 {
1762 return 1;
1763 }
1764
1765 static struct bpf_prog_dummy {
1766 struct bpf_prog prog;
1767 } dummy_bpf_prog = {
1768 .prog = {
1769 .bpf_func = __bpf_prog_ret1,
1770 },
1771 };
1772
1773 /* to avoid allocating empty bpf_prog_array for cgroups that
1774 * don't have bpf program attached use one global 'empty_prog_array'
1775 * It will not be modified the caller of bpf_prog_array_alloc()
1776 * (since caller requested prog_cnt == 0)
1777 * that pointer should be 'freed' by bpf_prog_array_free()
1778 */
1779 static struct {
1780 struct bpf_prog_array hdr;
1781 struct bpf_prog *null_prog;
1782 } empty_prog_array = {
1783 .null_prog = NULL,
1784 };
1785
1786 struct bpf_prog_array *bpf_prog_array_alloc(u32 prog_cnt, gfp_t flags)
1787 {
1788 if (prog_cnt)
1789 return kzalloc(sizeof(struct bpf_prog_array) +
1790 sizeof(struct bpf_prog_array_item) *
1791 (prog_cnt + 1),
1792 flags);
1793
1794 return &empty_prog_array.hdr;
1795 }
1796
1797 void bpf_prog_array_free(struct bpf_prog_array __rcu *progs)
1798 {
1799 if (!progs ||
1800 progs == (struct bpf_prog_array __rcu *)&empty_prog_array.hdr)
1801 return;
1802 kfree_rcu(progs, rcu);
1803 }
1804
1805 int bpf_prog_array_length(struct bpf_prog_array __rcu *array)
1806 {
1807 struct bpf_prog_array_item *item;
1808 u32 cnt = 0;
1809
1810 rcu_read_lock();
1811 item = rcu_dereference(array)->items;
1812 for (; item->prog; item++)
1813 if (item->prog != &dummy_bpf_prog.prog)
1814 cnt++;
1815 rcu_read_unlock();
1816 return cnt;
1817 }
1818
1819
1820 static bool bpf_prog_array_copy_core(struct bpf_prog_array __rcu *array,
1821 u32 *prog_ids,
1822 u32 request_cnt)
1823 {
1824 struct bpf_prog_array_item *item;
1825 int i = 0;
1826
1827 item = rcu_dereference_check(array, 1)->items;
1828 for (; item->prog; item++) {
1829 if (item->prog == &dummy_bpf_prog.prog)
1830 continue;
1831 prog_ids[i] = item->prog->aux->id;
1832 if (++i == request_cnt) {
1833 item++;
1834 break;
1835 }
1836 }
1837
1838 return !!(item->prog);
1839 }
1840
1841 int bpf_prog_array_copy_to_user(struct bpf_prog_array __rcu *array,
1842 __u32 __user *prog_ids, u32 cnt)
1843 {
1844 unsigned long err = 0;
1845 bool nospc;
1846 u32 *ids;
1847
1848 /* users of this function are doing:
1849 * cnt = bpf_prog_array_length();
1850 * if (cnt > 0)
1851 * bpf_prog_array_copy_to_user(..., cnt);
1852 * so below kcalloc doesn't need extra cnt > 0 check, but
1853 * bpf_prog_array_length() releases rcu lock and
1854 * prog array could have been swapped with empty or larger array,
1855 * so always copy 'cnt' prog_ids to the user.
1856 * In a rare race the user will see zero prog_ids
1857 */
1858 ids = kcalloc(cnt, sizeof(u32), GFP_USER | __GFP_NOWARN);
1859 if (!ids)
1860 return -ENOMEM;
1861 rcu_read_lock();
1862 nospc = bpf_prog_array_copy_core(array, ids, cnt);
1863 rcu_read_unlock();
1864 err = copy_to_user(prog_ids, ids, cnt * sizeof(u32));
1865 kfree(ids);
1866 if (err)
1867 return -EFAULT;
1868 if (nospc)
1869 return -ENOSPC;
1870 return 0;
1871 }
1872
1873 void bpf_prog_array_delete_safe(struct bpf_prog_array __rcu *array,
1874 struct bpf_prog *old_prog)
1875 {
1876 struct bpf_prog_array_item *item = array->items;
1877
1878 for (; item->prog; item++)
1879 if (item->prog == old_prog) {
1880 WRITE_ONCE(item->prog, &dummy_bpf_prog.prog);
1881 break;
1882 }
1883 }
1884
1885 int bpf_prog_array_copy(struct bpf_prog_array __rcu *old_array,
1886 struct bpf_prog *exclude_prog,
1887 struct bpf_prog *include_prog,
1888 struct bpf_prog_array **new_array)
1889 {
1890 int new_prog_cnt, carry_prog_cnt = 0;
1891 struct bpf_prog_array_item *existing;
1892 struct bpf_prog_array *array;
1893 bool found_exclude = false;
1894 int new_prog_idx = 0;
1895
1896 /* Figure out how many existing progs we need to carry over to
1897 * the new array.
1898 */
1899 if (old_array) {
1900 existing = old_array->items;
1901 for (; existing->prog; existing++) {
1902 if (existing->prog == exclude_prog) {
1903 found_exclude = true;
1904 continue;
1905 }
1906 if (existing->prog != &dummy_bpf_prog.prog)
1907 carry_prog_cnt++;
1908 if (existing->prog == include_prog)
1909 return -EEXIST;
1910 }
1911 }
1912
1913 if (exclude_prog && !found_exclude)
1914 return -ENOENT;
1915
1916 /* How many progs (not NULL) will be in the new array? */
1917 new_prog_cnt = carry_prog_cnt;
1918 if (include_prog)
1919 new_prog_cnt += 1;
1920
1921 /* Do we have any prog (not NULL) in the new array? */
1922 if (!new_prog_cnt) {
1923 *new_array = NULL;
1924 return 0;
1925 }
1926
1927 /* +1 as the end of prog_array is marked with NULL */
1928 array = bpf_prog_array_alloc(new_prog_cnt + 1, GFP_KERNEL);
1929 if (!array)
1930 return -ENOMEM;
1931
1932 /* Fill in the new prog array */
1933 if (carry_prog_cnt) {
1934 existing = old_array->items;
1935 for (; existing->prog; existing++)
1936 if (existing->prog != exclude_prog &&
1937 existing->prog != &dummy_bpf_prog.prog) {
1938 array->items[new_prog_idx++].prog =
1939 existing->prog;
1940 }
1941 }
1942 if (include_prog)
1943 array->items[new_prog_idx++].prog = include_prog;
1944 array->items[new_prog_idx].prog = NULL;
1945 *new_array = array;
1946 return 0;
1947 }
1948
1949 int bpf_prog_array_copy_info(struct bpf_prog_array __rcu *array,
1950 u32 *prog_ids, u32 request_cnt,
1951 u32 *prog_cnt)
1952 {
1953 u32 cnt = 0;
1954
1955 if (array)
1956 cnt = bpf_prog_array_length(array);
1957
1958 *prog_cnt = cnt;
1959
1960 /* return early if user requested only program count or nothing to copy */
1961 if (!request_cnt || !cnt)
1962 return 0;
1963
1964 /* this function is called under trace/bpf_trace.c: bpf_event_mutex */
1965 return bpf_prog_array_copy_core(array, prog_ids, request_cnt) ? -ENOSPC
1966 : 0;
1967 }
1968
1969 static void bpf_prog_free_deferred(struct work_struct *work)
1970 {
1971 struct bpf_prog_aux *aux;
1972 int i;
1973
1974 aux = container_of(work, struct bpf_prog_aux, work);
1975 if (bpf_prog_is_dev_bound(aux))
1976 bpf_prog_offload_destroy(aux->prog);
1977 #ifdef CONFIG_PERF_EVENTS
1978 if (aux->prog->has_callchain_buf)
1979 put_callchain_buffers();
1980 #endif
1981 for (i = 0; i < aux->func_cnt; i++)
1982 bpf_jit_free(aux->func[i]);
1983 if (aux->func_cnt) {
1984 kfree(aux->func);
1985 bpf_prog_unlock_free(aux->prog);
1986 } else {
1987 bpf_jit_free(aux->prog);
1988 }
1989 }
1990
1991 /* Free internal BPF program */
1992 void bpf_prog_free(struct bpf_prog *fp)
1993 {
1994 struct bpf_prog_aux *aux = fp->aux;
1995
1996 INIT_WORK(&aux->work, bpf_prog_free_deferred);
1997 schedule_work(&aux->work);
1998 }
1999 EXPORT_SYMBOL_GPL(bpf_prog_free);
2000
2001 /* RNG for unpriviledged user space with separated state from prandom_u32(). */
2002 static DEFINE_PER_CPU(struct rnd_state, bpf_user_rnd_state);
2003
2004 void bpf_user_rnd_init_once(void)
2005 {
2006 prandom_init_once(&bpf_user_rnd_state);
2007 }
2008
2009 BPF_CALL_0(bpf_user_rnd_u32)
2010 {
2011 /* Should someone ever have the rather unwise idea to use some
2012 * of the registers passed into this function, then note that
2013 * this function is called from native eBPF and classic-to-eBPF
2014 * transformations. Register assignments from both sides are
2015 * different, f.e. classic always sets fn(ctx, A, X) here.
2016 */
2017 struct rnd_state *state;
2018 u32 res;
2019
2020 state = &get_cpu_var(bpf_user_rnd_state);
2021 res = prandom_u32_state(state);
2022 put_cpu_var(bpf_user_rnd_state);
2023
2024 return res;
2025 }
2026
2027 /* Weak definitions of helper functions in case we don't have bpf syscall. */
2028 const struct bpf_func_proto bpf_map_lookup_elem_proto __weak;
2029 const struct bpf_func_proto bpf_map_update_elem_proto __weak;
2030 const struct bpf_func_proto bpf_map_delete_elem_proto __weak;
2031 const struct bpf_func_proto bpf_map_push_elem_proto __weak;
2032 const struct bpf_func_proto bpf_map_pop_elem_proto __weak;
2033 const struct bpf_func_proto bpf_map_peek_elem_proto __weak;
2034 const struct bpf_func_proto bpf_spin_lock_proto __weak;
2035 const struct bpf_func_proto bpf_spin_unlock_proto __weak;
2036
2037 const struct bpf_func_proto bpf_get_prandom_u32_proto __weak;
2038 const struct bpf_func_proto bpf_get_smp_processor_id_proto __weak;
2039 const struct bpf_func_proto bpf_get_numa_node_id_proto __weak;
2040 const struct bpf_func_proto bpf_ktime_get_ns_proto __weak;
2041
2042 const struct bpf_func_proto bpf_get_current_pid_tgid_proto __weak;
2043 const struct bpf_func_proto bpf_get_current_uid_gid_proto __weak;
2044 const struct bpf_func_proto bpf_get_current_comm_proto __weak;
2045 const struct bpf_func_proto bpf_get_current_cgroup_id_proto __weak;
2046 const struct bpf_func_proto bpf_get_local_storage_proto __weak;
2047
2048 const struct bpf_func_proto * __weak bpf_get_trace_printk_proto(void)
2049 {
2050 return NULL;
2051 }
2052
2053 u64 __weak
2054 bpf_event_output(struct bpf_map *map, u64 flags, void *meta, u64 meta_size,
2055 void *ctx, u64 ctx_size, bpf_ctx_copy_t ctx_copy)
2056 {
2057 return -ENOTSUPP;
2058 }
2059 EXPORT_SYMBOL_GPL(bpf_event_output);
2060
2061 /* Always built-in helper functions. */
2062 const struct bpf_func_proto bpf_tail_call_proto = {
2063 .func = NULL,
2064 .gpl_only = false,
2065 .ret_type = RET_VOID,
2066 .arg1_type = ARG_PTR_TO_CTX,
2067 .arg2_type = ARG_CONST_MAP_PTR,
2068 .arg3_type = ARG_ANYTHING,
2069 };
2070
2071 /* Stub for JITs that only support cBPF. eBPF programs are interpreted.
2072 * It is encouraged to implement bpf_int_jit_compile() instead, so that
2073 * eBPF and implicitly also cBPF can get JITed!
2074 */
2075 struct bpf_prog * __weak bpf_int_jit_compile(struct bpf_prog *prog)
2076 {
2077 return prog;
2078 }
2079
2080 /* Stub for JITs that support eBPF. All cBPF code gets transformed into
2081 * eBPF by the kernel and is later compiled by bpf_int_jit_compile().
2082 */
2083 void __weak bpf_jit_compile(struct bpf_prog *prog)
2084 {
2085 }
2086
2087 bool __weak bpf_helper_changes_pkt_data(void *func)
2088 {
2089 return false;
2090 }
2091
2092 /* To execute LD_ABS/LD_IND instructions __bpf_prog_run() may call
2093 * skb_copy_bits(), so provide a weak definition of it for NET-less config.
2094 */
2095 int __weak skb_copy_bits(const struct sk_buff *skb, int offset, void *to,
2096 int len)
2097 {
2098 return -EFAULT;
2099 }
2100
2101 DEFINE_STATIC_KEY_FALSE(bpf_stats_enabled_key);
2102 EXPORT_SYMBOL(bpf_stats_enabled_key);
2103 int sysctl_bpf_stats_enabled __read_mostly;
2104
2105 /* All definitions of tracepoints related to BPF. */
2106 #define CREATE_TRACE_POINTS
2107 #include <linux/bpf_trace.h>
2108
2109 EXPORT_TRACEPOINT_SYMBOL_GPL(xdp_exception);
Linux with added FPC-III support