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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 <linux/filter.h>
25 #include <linux/skbuff.h>
26 #include <linux/vmalloc.h>
27 #include <linux/random.h>
28 #include <linux/moduleloader.h>
29 #include <linux/bpf.h>
30 #include <linux/frame.h>
31 #include <linux/rbtree_latch.h>
32 #include <linux/kallsyms.h>
33 #include <linux/rcupdate.h>
34 #include <linux/perf_event.h>
35
36 #include <asm/unaligned.h>
37
38 /* Registers */
39 #define BPF_R0 regs[BPF_REG_0]
40 #define BPF_R1 regs[BPF_REG_1]
41 #define BPF_R2 regs[BPF_REG_2]
42 #define BPF_R3 regs[BPF_REG_3]
43 #define BPF_R4 regs[BPF_REG_4]
44 #define BPF_R5 regs[BPF_REG_5]
45 #define BPF_R6 regs[BPF_REG_6]
46 #define BPF_R7 regs[BPF_REG_7]
47 #define BPF_R8 regs[BPF_REG_8]
48 #define BPF_R9 regs[BPF_REG_9]
49 #define BPF_R10 regs[BPF_REG_10]
50
51 /* Named registers */
52 #define DST regs[insn->dst_reg]
53 #define SRC regs[insn->src_reg]
54 #define FP regs[BPF_REG_FP]
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(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, PAGE_KERNEL);
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 EXPORT_SYMBOL_GPL(bpf_prog_alloc);
105
106 struct bpf_prog *bpf_prog_realloc(struct bpf_prog *fp_old, unsigned int size,
107 gfp_t gfp_extra_flags)
108 {
109 gfp_t gfp_flags = GFP_KERNEL | __GFP_ZERO | gfp_extra_flags;
110 struct bpf_prog *fp;
111 u32 pages, delta;
112 int ret;
113
114 BUG_ON(fp_old == NULL);
115
116 size = round_up(size, PAGE_SIZE);
117 pages = size / PAGE_SIZE;
118 if (pages <= fp_old->pages)
119 return fp_old;
120
121 delta = pages - fp_old->pages;
122 ret = __bpf_prog_charge(fp_old->aux->user, delta);
123 if (ret)
124 return NULL;
125
126 fp = __vmalloc(size, gfp_flags, PAGE_KERNEL);
127 if (fp == NULL) {
128 __bpf_prog_uncharge(fp_old->aux->user, delta);
129 } else {
130 memcpy(fp, fp_old, fp_old->pages * PAGE_SIZE);
131 fp->pages = pages;
132 fp->aux->prog = fp;
133
134 /* We keep fp->aux from fp_old around in the new
135 * reallocated structure.
136 */
137 fp_old->aux = NULL;
138 __bpf_prog_free(fp_old);
139 }
140
141 return fp;
142 }
143
144 void __bpf_prog_free(struct bpf_prog *fp)
145 {
146 kfree(fp->aux);
147 vfree(fp);
148 }
149
150 int bpf_prog_calc_tag(struct bpf_prog *fp)
151 {
152 const u32 bits_offset = SHA_MESSAGE_BYTES - sizeof(__be64);
153 u32 raw_size = bpf_prog_tag_scratch_size(fp);
154 u32 digest[SHA_DIGEST_WORDS];
155 u32 ws[SHA_WORKSPACE_WORDS];
156 u32 i, bsize, psize, blocks;
157 struct bpf_insn *dst;
158 bool was_ld_map;
159 u8 *raw, *todo;
160 __be32 *result;
161 __be64 *bits;
162
163 raw = vmalloc(raw_size);
164 if (!raw)
165 return -ENOMEM;
166
167 sha_init(digest);
168 memset(ws, 0, sizeof(ws));
169
170 /* We need to take out the map fd for the digest calculation
171 * since they are unstable from user space side.
172 */
173 dst = (void *)raw;
174 for (i = 0, was_ld_map = false; i < fp->len; i++) {
175 dst[i] = fp->insnsi[i];
176 if (!was_ld_map &&
177 dst[i].code == (BPF_LD | BPF_IMM | BPF_DW) &&
178 dst[i].src_reg == BPF_PSEUDO_MAP_FD) {
179 was_ld_map = true;
180 dst[i].imm = 0;
181 } else if (was_ld_map &&
182 dst[i].code == 0 &&
183 dst[i].dst_reg == 0 &&
184 dst[i].src_reg == 0 &&
185 dst[i].off == 0) {
186 was_ld_map = false;
187 dst[i].imm = 0;
188 } else {
189 was_ld_map = false;
190 }
191 }
192
193 psize = bpf_prog_insn_size(fp);
194 memset(&raw[psize], 0, raw_size - psize);
195 raw[psize++] = 0x80;
196
197 bsize = round_up(psize, SHA_MESSAGE_BYTES);
198 blocks = bsize / SHA_MESSAGE_BYTES;
199 todo = raw;
200 if (bsize - psize >= sizeof(__be64)) {
201 bits = (__be64 *)(todo + bsize - sizeof(__be64));
202 } else {
203 bits = (__be64 *)(todo + bsize + bits_offset);
204 blocks++;
205 }
206 *bits = cpu_to_be64((psize - 1) << 3);
207
208 while (blocks--) {
209 sha_transform(digest, todo, ws);
210 todo += SHA_MESSAGE_BYTES;
211 }
212
213 result = (__force __be32 *)digest;
214 for (i = 0; i < SHA_DIGEST_WORDS; i++)
215 result[i] = cpu_to_be32(digest[i]);
216 memcpy(fp->tag, result, sizeof(fp->tag));
217
218 vfree(raw);
219 return 0;
220 }
221
222 static void bpf_adj_branches(struct bpf_prog *prog, u32 pos, u32 delta)
223 {
224 struct bpf_insn *insn = prog->insnsi;
225 u32 i, insn_cnt = prog->len;
226 bool pseudo_call;
227 u8 code;
228 int off;
229
230 for (i = 0; i < insn_cnt; i++, insn++) {
231 code = insn->code;
232 if (BPF_CLASS(code) != BPF_JMP)
233 continue;
234 if (BPF_OP(code) == BPF_EXIT)
235 continue;
236 if (BPF_OP(code) == BPF_CALL) {
237 if (insn->src_reg == BPF_PSEUDO_CALL)
238 pseudo_call = true;
239 else
240 continue;
241 } else {
242 pseudo_call = false;
243 }
244 off = pseudo_call ? insn->imm : insn->off;
245
246 /* Adjust offset of jmps if we cross boundaries. */
247 if (i < pos && i + off + 1 > pos)
248 off += delta;
249 else if (i > pos + delta && i + off + 1 <= pos + delta)
250 off -= delta;
251
252 if (pseudo_call)
253 insn->imm = off;
254 else
255 insn->off = off;
256 }
257 }
258
259 struct bpf_prog *bpf_patch_insn_single(struct bpf_prog *prog, u32 off,
260 const struct bpf_insn *patch, u32 len)
261 {
262 u32 insn_adj_cnt, insn_rest, insn_delta = len - 1;
263 struct bpf_prog *prog_adj;
264
265 /* Since our patchlet doesn't expand the image, we're done. */
266 if (insn_delta == 0) {
267 memcpy(prog->insnsi + off, patch, sizeof(*patch));
268 return prog;
269 }
270
271 insn_adj_cnt = prog->len + insn_delta;
272
273 /* Several new instructions need to be inserted. Make room
274 * for them. Likely, there's no need for a new allocation as
275 * last page could have large enough tailroom.
276 */
277 prog_adj = bpf_prog_realloc(prog, bpf_prog_size(insn_adj_cnt),
278 GFP_USER);
279 if (!prog_adj)
280 return NULL;
281
282 prog_adj->len = insn_adj_cnt;
283
284 /* Patching happens in 3 steps:
285 *
286 * 1) Move over tail of insnsi from next instruction onwards,
287 * so we can patch the single target insn with one or more
288 * new ones (patching is always from 1 to n insns, n > 0).
289 * 2) Inject new instructions at the target location.
290 * 3) Adjust branch offsets if necessary.
291 */
292 insn_rest = insn_adj_cnt - off - len;
293
294 memmove(prog_adj->insnsi + off + len, prog_adj->insnsi + off + 1,
295 sizeof(*patch) * insn_rest);
296 memcpy(prog_adj->insnsi + off, patch, sizeof(*patch) * len);
297
298 bpf_adj_branches(prog_adj, off, insn_delta);
299
300 return prog_adj;
301 }
302
303 #ifdef CONFIG_BPF_JIT
304 /* All BPF JIT sysctl knobs here. */
305 int bpf_jit_enable __read_mostly = IS_BUILTIN(CONFIG_BPF_JIT_ALWAYS_ON);
306 int bpf_jit_harden __read_mostly;
307 int bpf_jit_kallsyms __read_mostly;
308
309 static __always_inline void
310 bpf_get_prog_addr_region(const struct bpf_prog *prog,
311 unsigned long *symbol_start,
312 unsigned long *symbol_end)
313 {
314 const struct bpf_binary_header *hdr = bpf_jit_binary_hdr(prog);
315 unsigned long addr = (unsigned long)hdr;
316
317 WARN_ON_ONCE(!bpf_prog_ebpf_jited(prog));
318
319 *symbol_start = addr;
320 *symbol_end = addr + hdr->pages * PAGE_SIZE;
321 }
322
323 static void bpf_get_prog_name(const struct bpf_prog *prog, char *sym)
324 {
325 const char *end = sym + KSYM_NAME_LEN;
326
327 BUILD_BUG_ON(sizeof("bpf_prog_") +
328 sizeof(prog->tag) * 2 +
329 /* name has been null terminated.
330 * We should need +1 for the '_' preceding
331 * the name. However, the null character
332 * is double counted between the name and the
333 * sizeof("bpf_prog_") above, so we omit
334 * the +1 here.
335 */
336 sizeof(prog->aux->name) > KSYM_NAME_LEN);
337
338 sym += snprintf(sym, KSYM_NAME_LEN, "bpf_prog_");
339 sym = bin2hex(sym, prog->tag, sizeof(prog->tag));
340 if (prog->aux->name[0])
341 snprintf(sym, (size_t)(end - sym), "_%s", prog->aux->name);
342 else
343 *sym = 0;
344 }
345
346 static __always_inline unsigned long
347 bpf_get_prog_addr_start(struct latch_tree_node *n)
348 {
349 unsigned long symbol_start, symbol_end;
350 const struct bpf_prog_aux *aux;
351
352 aux = container_of(n, struct bpf_prog_aux, ksym_tnode);
353 bpf_get_prog_addr_region(aux->prog, &symbol_start, &symbol_end);
354
355 return symbol_start;
356 }
357
358 static __always_inline bool bpf_tree_less(struct latch_tree_node *a,
359 struct latch_tree_node *b)
360 {
361 return bpf_get_prog_addr_start(a) < bpf_get_prog_addr_start(b);
362 }
363
364 static __always_inline int bpf_tree_comp(void *key, struct latch_tree_node *n)
365 {
366 unsigned long val = (unsigned long)key;
367 unsigned long symbol_start, symbol_end;
368 const struct bpf_prog_aux *aux;
369
370 aux = container_of(n, struct bpf_prog_aux, ksym_tnode);
371 bpf_get_prog_addr_region(aux->prog, &symbol_start, &symbol_end);
372
373 if (val < symbol_start)
374 return -1;
375 if (val >= symbol_end)
376 return 1;
377
378 return 0;
379 }
380
381 static const struct latch_tree_ops bpf_tree_ops = {
382 .less = bpf_tree_less,
383 .comp = bpf_tree_comp,
384 };
385
386 static DEFINE_SPINLOCK(bpf_lock);
387 static LIST_HEAD(bpf_kallsyms);
388 static struct latch_tree_root bpf_tree __cacheline_aligned;
389
390 static void bpf_prog_ksym_node_add(struct bpf_prog_aux *aux)
391 {
392 WARN_ON_ONCE(!list_empty(&aux->ksym_lnode));
393 list_add_tail_rcu(&aux->ksym_lnode, &bpf_kallsyms);
394 latch_tree_insert(&aux->ksym_tnode, &bpf_tree, &bpf_tree_ops);
395 }
396
397 static void bpf_prog_ksym_node_del(struct bpf_prog_aux *aux)
398 {
399 if (list_empty(&aux->ksym_lnode))
400 return;
401
402 latch_tree_erase(&aux->ksym_tnode, &bpf_tree, &bpf_tree_ops);
403 list_del_rcu(&aux->ksym_lnode);
404 }
405
406 static bool bpf_prog_kallsyms_candidate(const struct bpf_prog *fp)
407 {
408 return fp->jited && !bpf_prog_was_classic(fp);
409 }
410
411 static bool bpf_prog_kallsyms_verify_off(const struct bpf_prog *fp)
412 {
413 return list_empty(&fp->aux->ksym_lnode) ||
414 fp->aux->ksym_lnode.prev == LIST_POISON2;
415 }
416
417 void bpf_prog_kallsyms_add(struct bpf_prog *fp)
418 {
419 if (!bpf_prog_kallsyms_candidate(fp) ||
420 !capable(CAP_SYS_ADMIN))
421 return;
422
423 spin_lock_bh(&bpf_lock);
424 bpf_prog_ksym_node_add(fp->aux);
425 spin_unlock_bh(&bpf_lock);
426 }
427
428 void bpf_prog_kallsyms_del(struct bpf_prog *fp)
429 {
430 if (!bpf_prog_kallsyms_candidate(fp))
431 return;
432
433 spin_lock_bh(&bpf_lock);
434 bpf_prog_ksym_node_del(fp->aux);
435 spin_unlock_bh(&bpf_lock);
436 }
437
438 static struct bpf_prog *bpf_prog_kallsyms_find(unsigned long addr)
439 {
440 struct latch_tree_node *n;
441
442 if (!bpf_jit_kallsyms_enabled())
443 return NULL;
444
445 n = latch_tree_find((void *)addr, &bpf_tree, &bpf_tree_ops);
446 return n ?
447 container_of(n, struct bpf_prog_aux, ksym_tnode)->prog :
448 NULL;
449 }
450
451 const char *__bpf_address_lookup(unsigned long addr, unsigned long *size,
452 unsigned long *off, char *sym)
453 {
454 unsigned long symbol_start, symbol_end;
455 struct bpf_prog *prog;
456 char *ret = NULL;
457
458 rcu_read_lock();
459 prog = bpf_prog_kallsyms_find(addr);
460 if (prog) {
461 bpf_get_prog_addr_region(prog, &symbol_start, &symbol_end);
462 bpf_get_prog_name(prog, sym);
463
464 ret = sym;
465 if (size)
466 *size = symbol_end - symbol_start;
467 if (off)
468 *off = addr - symbol_start;
469 }
470 rcu_read_unlock();
471
472 return ret;
473 }
474
475 bool is_bpf_text_address(unsigned long addr)
476 {
477 bool ret;
478
479 rcu_read_lock();
480 ret = bpf_prog_kallsyms_find(addr) != NULL;
481 rcu_read_unlock();
482
483 return ret;
484 }
485
486 int bpf_get_kallsym(unsigned int symnum, unsigned long *value, char *type,
487 char *sym)
488 {
489 unsigned long symbol_start, symbol_end;
490 struct bpf_prog_aux *aux;
491 unsigned int it = 0;
492 int ret = -ERANGE;
493
494 if (!bpf_jit_kallsyms_enabled())
495 return ret;
496
497 rcu_read_lock();
498 list_for_each_entry_rcu(aux, &bpf_kallsyms, ksym_lnode) {
499 if (it++ != symnum)
500 continue;
501
502 bpf_get_prog_addr_region(aux->prog, &symbol_start, &symbol_end);
503 bpf_get_prog_name(aux->prog, sym);
504
505 *value = symbol_start;
506 *type = BPF_SYM_ELF_TYPE;
507
508 ret = 0;
509 break;
510 }
511 rcu_read_unlock();
512
513 return ret;
514 }
515
516 struct bpf_binary_header *
517 bpf_jit_binary_alloc(unsigned int proglen, u8 **image_ptr,
518 unsigned int alignment,
519 bpf_jit_fill_hole_t bpf_fill_ill_insns)
520 {
521 struct bpf_binary_header *hdr;
522 unsigned int size, hole, start;
523
524 /* Most of BPF filters are really small, but if some of them
525 * fill a page, allow at least 128 extra bytes to insert a
526 * random section of illegal instructions.
527 */
528 size = round_up(proglen + sizeof(*hdr) + 128, PAGE_SIZE);
529 hdr = module_alloc(size);
530 if (hdr == NULL)
531 return NULL;
532
533 /* Fill space with illegal/arch-dep instructions. */
534 bpf_fill_ill_insns(hdr, size);
535
536 hdr->pages = size / PAGE_SIZE;
537 hole = min_t(unsigned int, size - (proglen + sizeof(*hdr)),
538 PAGE_SIZE - sizeof(*hdr));
539 start = (get_random_int() % hole) & ~(alignment - 1);
540
541 /* Leave a random number of instructions before BPF code. */
542 *image_ptr = &hdr->image[start];
543
544 return hdr;
545 }
546
547 void bpf_jit_binary_free(struct bpf_binary_header *hdr)
548 {
549 module_memfree(hdr);
550 }
551
552 /* This symbol is only overridden by archs that have different
553 * requirements than the usual eBPF JITs, f.e. when they only
554 * implement cBPF JIT, do not set images read-only, etc.
555 */
556 void __weak bpf_jit_free(struct bpf_prog *fp)
557 {
558 if (fp->jited) {
559 struct bpf_binary_header *hdr = bpf_jit_binary_hdr(fp);
560
561 bpf_jit_binary_unlock_ro(hdr);
562 bpf_jit_binary_free(hdr);
563
564 WARN_ON_ONCE(!bpf_prog_kallsyms_verify_off(fp));
565 }
566
567 bpf_prog_unlock_free(fp);
568 }
569
570 static int bpf_jit_blind_insn(const struct bpf_insn *from,
571 const struct bpf_insn *aux,
572 struct bpf_insn *to_buff)
573 {
574 struct bpf_insn *to = to_buff;
575 u32 imm_rnd = get_random_int();
576 s16 off;
577
578 BUILD_BUG_ON(BPF_REG_AX + 1 != MAX_BPF_JIT_REG);
579 BUILD_BUG_ON(MAX_BPF_REG + 1 != MAX_BPF_JIT_REG);
580
581 if (from->imm == 0 &&
582 (from->code == (BPF_ALU | BPF_MOV | BPF_K) ||
583 from->code == (BPF_ALU64 | BPF_MOV | BPF_K))) {
584 *to++ = BPF_ALU64_REG(BPF_XOR, from->dst_reg, from->dst_reg);
585 goto out;
586 }
587
588 switch (from->code) {
589 case BPF_ALU | BPF_ADD | BPF_K:
590 case BPF_ALU | BPF_SUB | BPF_K:
591 case BPF_ALU | BPF_AND | BPF_K:
592 case BPF_ALU | BPF_OR | BPF_K:
593 case BPF_ALU | BPF_XOR | BPF_K:
594 case BPF_ALU | BPF_MUL | BPF_K:
595 case BPF_ALU | BPF_MOV | BPF_K:
596 case BPF_ALU | BPF_DIV | BPF_K:
597 case BPF_ALU | BPF_MOD | BPF_K:
598 *to++ = BPF_ALU32_IMM(BPF_MOV, BPF_REG_AX, imm_rnd ^ from->imm);
599 *to++ = BPF_ALU32_IMM(BPF_XOR, BPF_REG_AX, imm_rnd);
600 *to++ = BPF_ALU32_REG(from->code, from->dst_reg, BPF_REG_AX);
601 break;
602
603 case BPF_ALU64 | BPF_ADD | BPF_K:
604 case BPF_ALU64 | BPF_SUB | BPF_K:
605 case BPF_ALU64 | BPF_AND | BPF_K:
606 case BPF_ALU64 | BPF_OR | BPF_K:
607 case BPF_ALU64 | BPF_XOR | BPF_K:
608 case BPF_ALU64 | BPF_MUL | BPF_K:
609 case BPF_ALU64 | BPF_MOV | BPF_K:
610 case BPF_ALU64 | BPF_DIV | BPF_K:
611 case BPF_ALU64 | BPF_MOD | BPF_K:
612 *to++ = BPF_ALU64_IMM(BPF_MOV, BPF_REG_AX, imm_rnd ^ from->imm);
613 *to++ = BPF_ALU64_IMM(BPF_XOR, BPF_REG_AX, imm_rnd);
614 *to++ = BPF_ALU64_REG(from->code, from->dst_reg, BPF_REG_AX);
615 break;
616
617 case BPF_JMP | BPF_JEQ | BPF_K:
618 case BPF_JMP | BPF_JNE | BPF_K:
619 case BPF_JMP | BPF_JGT | BPF_K:
620 case BPF_JMP | BPF_JLT | BPF_K:
621 case BPF_JMP | BPF_JGE | BPF_K:
622 case BPF_JMP | BPF_JLE | BPF_K:
623 case BPF_JMP | BPF_JSGT | BPF_K:
624 case BPF_JMP | BPF_JSLT | BPF_K:
625 case BPF_JMP | BPF_JSGE | BPF_K:
626 case BPF_JMP | BPF_JSLE | BPF_K:
627 case BPF_JMP | BPF_JSET | BPF_K:
628 /* Accommodate for extra offset in case of a backjump. */
629 off = from->off;
630 if (off < 0)
631 off -= 2;
632 *to++ = BPF_ALU64_IMM(BPF_MOV, BPF_REG_AX, imm_rnd ^ from->imm);
633 *to++ = BPF_ALU64_IMM(BPF_XOR, BPF_REG_AX, imm_rnd);
634 *to++ = BPF_JMP_REG(from->code, from->dst_reg, BPF_REG_AX, off);
635 break;
636
637 case BPF_LD | BPF_IMM | BPF_DW:
638 *to++ = BPF_ALU64_IMM(BPF_MOV, BPF_REG_AX, imm_rnd ^ aux[1].imm);
639 *to++ = BPF_ALU64_IMM(BPF_XOR, BPF_REG_AX, imm_rnd);
640 *to++ = BPF_ALU64_IMM(BPF_LSH, BPF_REG_AX, 32);
641 *to++ = BPF_ALU64_REG(BPF_MOV, aux[0].dst_reg, BPF_REG_AX);
642 break;
643 case 0: /* Part 2 of BPF_LD | BPF_IMM | BPF_DW. */
644 *to++ = BPF_ALU32_IMM(BPF_MOV, BPF_REG_AX, imm_rnd ^ aux[0].imm);
645 *to++ = BPF_ALU32_IMM(BPF_XOR, BPF_REG_AX, imm_rnd);
646 *to++ = BPF_ALU64_REG(BPF_OR, aux[0].dst_reg, BPF_REG_AX);
647 break;
648
649 case BPF_ST | BPF_MEM | BPF_DW:
650 case BPF_ST | BPF_MEM | BPF_W:
651 case BPF_ST | BPF_MEM | BPF_H:
652 case BPF_ST | BPF_MEM | BPF_B:
653 *to++ = BPF_ALU64_IMM(BPF_MOV, BPF_REG_AX, imm_rnd ^ from->imm);
654 *to++ = BPF_ALU64_IMM(BPF_XOR, BPF_REG_AX, imm_rnd);
655 *to++ = BPF_STX_MEM(from->code, from->dst_reg, BPF_REG_AX, from->off);
656 break;
657 }
658 out:
659 return to - to_buff;
660 }
661
662 static struct bpf_prog *bpf_prog_clone_create(struct bpf_prog *fp_other,
663 gfp_t gfp_extra_flags)
664 {
665 gfp_t gfp_flags = GFP_KERNEL | __GFP_ZERO | gfp_extra_flags;
666 struct bpf_prog *fp;
667
668 fp = __vmalloc(fp_other->pages * PAGE_SIZE, gfp_flags, PAGE_KERNEL);
669 if (fp != NULL) {
670 /* aux->prog still points to the fp_other one, so
671 * when promoting the clone to the real program,
672 * this still needs to be adapted.
673 */
674 memcpy(fp, fp_other, fp_other->pages * PAGE_SIZE);
675 }
676
677 return fp;
678 }
679
680 static void bpf_prog_clone_free(struct bpf_prog *fp)
681 {
682 /* aux was stolen by the other clone, so we cannot free
683 * it from this path! It will be freed eventually by the
684 * other program on release.
685 *
686 * At this point, we don't need a deferred release since
687 * clone is guaranteed to not be locked.
688 */
689 fp->aux = NULL;
690 __bpf_prog_free(fp);
691 }
692
693 void bpf_jit_prog_release_other(struct bpf_prog *fp, struct bpf_prog *fp_other)
694 {
695 /* We have to repoint aux->prog to self, as we don't
696 * know whether fp here is the clone or the original.
697 */
698 fp->aux->prog = fp;
699 bpf_prog_clone_free(fp_other);
700 }
701
702 struct bpf_prog *bpf_jit_blind_constants(struct bpf_prog *prog)
703 {
704 struct bpf_insn insn_buff[16], aux[2];
705 struct bpf_prog *clone, *tmp;
706 int insn_delta, insn_cnt;
707 struct bpf_insn *insn;
708 int i, rewritten;
709
710 if (!bpf_jit_blinding_enabled(prog) || prog->blinded)
711 return prog;
712
713 clone = bpf_prog_clone_create(prog, GFP_USER);
714 if (!clone)
715 return ERR_PTR(-ENOMEM);
716
717 insn_cnt = clone->len;
718 insn = clone->insnsi;
719
720 for (i = 0; i < insn_cnt; i++, insn++) {
721 /* We temporarily need to hold the original ld64 insn
722 * so that we can still access the first part in the
723 * second blinding run.
724 */
725 if (insn[0].code == (BPF_LD | BPF_IMM | BPF_DW) &&
726 insn[1].code == 0)
727 memcpy(aux, insn, sizeof(aux));
728
729 rewritten = bpf_jit_blind_insn(insn, aux, insn_buff);
730 if (!rewritten)
731 continue;
732
733 tmp = bpf_patch_insn_single(clone, i, insn_buff, rewritten);
734 if (!tmp) {
735 /* Patching may have repointed aux->prog during
736 * realloc from the original one, so we need to
737 * fix it up here on error.
738 */
739 bpf_jit_prog_release_other(prog, clone);
740 return ERR_PTR(-ENOMEM);
741 }
742
743 clone = tmp;
744 insn_delta = rewritten - 1;
745
746 /* Walk new program and skip insns we just inserted. */
747 insn = clone->insnsi + i + insn_delta;
748 insn_cnt += insn_delta;
749 i += insn_delta;
750 }
751
752 clone->blinded = 1;
753 return clone;
754 }
755 #endif /* CONFIG_BPF_JIT */
756
757 /* Base function for offset calculation. Needs to go into .text section,
758 * therefore keeping it non-static as well; will also be used by JITs
759 * anyway later on, so do not let the compiler omit it. This also needs
760 * to go into kallsyms for correlation from e.g. bpftool, so naming
761 * must not change.
762 */
763 noinline u64 __bpf_call_base(u64 r1, u64 r2, u64 r3, u64 r4, u64 r5)
764 {
765 return 0;
766 }
767 EXPORT_SYMBOL_GPL(__bpf_call_base);
768
769 /* All UAPI available opcodes. */
770 #define BPF_INSN_MAP(INSN_2, INSN_3) \
771 /* 32 bit ALU operations. */ \
772 /* Register based. */ \
773 INSN_3(ALU, ADD, X), \
774 INSN_3(ALU, SUB, X), \
775 INSN_3(ALU, AND, X), \
776 INSN_3(ALU, OR, X), \
777 INSN_3(ALU, LSH, X), \
778 INSN_3(ALU, RSH, X), \
779 INSN_3(ALU, XOR, X), \
780 INSN_3(ALU, MUL, X), \
781 INSN_3(ALU, MOV, X), \
782 INSN_3(ALU, DIV, X), \
783 INSN_3(ALU, MOD, X), \
784 INSN_2(ALU, NEG), \
785 INSN_3(ALU, END, TO_BE), \
786 INSN_3(ALU, END, TO_LE), \
787 /* Immediate based. */ \
788 INSN_3(ALU, ADD, K), \
789 INSN_3(ALU, SUB, K), \
790 INSN_3(ALU, AND, K), \
791 INSN_3(ALU, OR, K), \
792 INSN_3(ALU, LSH, K), \
793 INSN_3(ALU, RSH, K), \
794 INSN_3(ALU, XOR, K), \
795 INSN_3(ALU, MUL, K), \
796 INSN_3(ALU, MOV, K), \
797 INSN_3(ALU, DIV, K), \
798 INSN_3(ALU, MOD, K), \
799 /* 64 bit ALU operations. */ \
800 /* Register based. */ \
801 INSN_3(ALU64, ADD, X), \
802 INSN_3(ALU64, SUB, X), \
803 INSN_3(ALU64, AND, X), \
804 INSN_3(ALU64, OR, X), \
805 INSN_3(ALU64, LSH, X), \
806 INSN_3(ALU64, RSH, X), \
807 INSN_3(ALU64, XOR, X), \
808 INSN_3(ALU64, MUL, X), \
809 INSN_3(ALU64, MOV, X), \
810 INSN_3(ALU64, ARSH, X), \
811 INSN_3(ALU64, DIV, X), \
812 INSN_3(ALU64, MOD, X), \
813 INSN_2(ALU64, NEG), \
814 /* Immediate based. */ \
815 INSN_3(ALU64, ADD, K), \
816 INSN_3(ALU64, SUB, K), \
817 INSN_3(ALU64, AND, K), \
818 INSN_3(ALU64, OR, K), \
819 INSN_3(ALU64, LSH, K), \
820 INSN_3(ALU64, RSH, K), \
821 INSN_3(ALU64, XOR, K), \
822 INSN_3(ALU64, MUL, K), \
823 INSN_3(ALU64, MOV, K), \
824 INSN_3(ALU64, ARSH, K), \
825 INSN_3(ALU64, DIV, K), \
826 INSN_3(ALU64, MOD, K), \
827 /* Call instruction. */ \
828 INSN_2(JMP, CALL), \
829 /* Exit instruction. */ \
830 INSN_2(JMP, EXIT), \
831 /* Jump instructions. */ \
832 /* Register based. */ \
833 INSN_3(JMP, JEQ, X), \
834 INSN_3(JMP, JNE, X), \
835 INSN_3(JMP, JGT, X), \
836 INSN_3(JMP, JLT, X), \
837 INSN_3(JMP, JGE, X), \
838 INSN_3(JMP, JLE, X), \
839 INSN_3(JMP, JSGT, X), \
840 INSN_3(JMP, JSLT, X), \
841 INSN_3(JMP, JSGE, X), \
842 INSN_3(JMP, JSLE, X), \
843 INSN_3(JMP, JSET, X), \
844 /* Immediate based. */ \
845 INSN_3(JMP, JEQ, K), \
846 INSN_3(JMP, JNE, K), \
847 INSN_3(JMP, JGT, K), \
848 INSN_3(JMP, JLT, K), \
849 INSN_3(JMP, JGE, K), \
850 INSN_3(JMP, JLE, K), \
851 INSN_3(JMP, JSGT, K), \
852 INSN_3(JMP, JSLT, K), \
853 INSN_3(JMP, JSGE, K), \
854 INSN_3(JMP, JSLE, K), \
855 INSN_3(JMP, JSET, K), \
856 INSN_2(JMP, JA), \
857 /* Store instructions. */ \
858 /* Register based. */ \
859 INSN_3(STX, MEM, B), \
860 INSN_3(STX, MEM, H), \
861 INSN_3(STX, MEM, W), \
862 INSN_3(STX, MEM, DW), \
863 INSN_3(STX, XADD, W), \
864 INSN_3(STX, XADD, DW), \
865 /* Immediate based. */ \
866 INSN_3(ST, MEM, B), \
867 INSN_3(ST, MEM, H), \
868 INSN_3(ST, MEM, W), \
869 INSN_3(ST, MEM, DW), \
870 /* Load instructions. */ \
871 /* Register based. */ \
872 INSN_3(LDX, MEM, B), \
873 INSN_3(LDX, MEM, H), \
874 INSN_3(LDX, MEM, W), \
875 INSN_3(LDX, MEM, DW), \
876 /* Immediate based. */ \
877 INSN_3(LD, IMM, DW)
878
879 bool bpf_opcode_in_insntable(u8 code)
880 {
881 #define BPF_INSN_2_TBL(x, y) [BPF_##x | BPF_##y] = true
882 #define BPF_INSN_3_TBL(x, y, z) [BPF_##x | BPF_##y | BPF_##z] = true
883 static const bool public_insntable[256] = {
884 [0 ... 255] = false,
885 /* Now overwrite non-defaults ... */
886 BPF_INSN_MAP(BPF_INSN_2_TBL, BPF_INSN_3_TBL),
887 /* UAPI exposed, but rewritten opcodes. cBPF carry-over. */
888 [BPF_LD | BPF_ABS | BPF_B] = true,
889 [BPF_LD | BPF_ABS | BPF_H] = true,
890 [BPF_LD | BPF_ABS | BPF_W] = true,
891 [BPF_LD | BPF_IND | BPF_B] = true,
892 [BPF_LD | BPF_IND | BPF_H] = true,
893 [BPF_LD | BPF_IND | BPF_W] = true,
894 };
895 #undef BPF_INSN_3_TBL
896 #undef BPF_INSN_2_TBL
897 return public_insntable[code];
898 }
899
900 #ifndef CONFIG_BPF_JIT_ALWAYS_ON
901 /**
902 * __bpf_prog_run - run eBPF program on a given context
903 * @ctx: is the data we are operating on
904 * @insn: is the array of eBPF instructions
905 *
906 * Decode and execute eBPF instructions.
907 */
908 static u64 ___bpf_prog_run(u64 *regs, const struct bpf_insn *insn, u64 *stack)
909 {
910 u64 tmp;
911 #define BPF_INSN_2_LBL(x, y) [BPF_##x | BPF_##y] = &&x##_##y
912 #define BPF_INSN_3_LBL(x, y, z) [BPF_##x | BPF_##y | BPF_##z] = &&x##_##y##_##z
913 static const void *jumptable[256] = {
914 [0 ... 255] = &&default_label,
915 /* Now overwrite non-defaults ... */
916 BPF_INSN_MAP(BPF_INSN_2_LBL, BPF_INSN_3_LBL),
917 /* Non-UAPI available opcodes. */
918 [BPF_JMP | BPF_CALL_ARGS] = &&JMP_CALL_ARGS,
919 [BPF_JMP | BPF_TAIL_CALL] = &&JMP_TAIL_CALL,
920 };
921 #undef BPF_INSN_3_LBL
922 #undef BPF_INSN_2_LBL
923 u32 tail_call_cnt = 0;
924
925 #define CONT ({ insn++; goto select_insn; })
926 #define CONT_JMP ({ insn++; goto select_insn; })
927
928 select_insn:
929 goto *jumptable[insn->code];
930
931 /* ALU */
932 #define ALU(OPCODE, OP) \
933 ALU64_##OPCODE##_X: \
934 DST = DST OP SRC; \
935 CONT; \
936 ALU_##OPCODE##_X: \
937 DST = (u32) DST OP (u32) SRC; \
938 CONT; \
939 ALU64_##OPCODE##_K: \
940 DST = DST OP IMM; \
941 CONT; \
942 ALU_##OPCODE##_K: \
943 DST = (u32) DST OP (u32) IMM; \
944 CONT;
945
946 ALU(ADD, +)
947 ALU(SUB, -)
948 ALU(AND, &)
949 ALU(OR, |)
950 ALU(LSH, <<)
951 ALU(RSH, >>)
952 ALU(XOR, ^)
953 ALU(MUL, *)
954 #undef ALU
955 ALU_NEG:
956 DST = (u32) -DST;
957 CONT;
958 ALU64_NEG:
959 DST = -DST;
960 CONT;
961 ALU_MOV_X:
962 DST = (u32) SRC;
963 CONT;
964 ALU_MOV_K:
965 DST = (u32) IMM;
966 CONT;
967 ALU64_MOV_X:
968 DST = SRC;
969 CONT;
970 ALU64_MOV_K:
971 DST = IMM;
972 CONT;
973 LD_IMM_DW:
974 DST = (u64) (u32) insn[0].imm | ((u64) (u32) insn[1].imm) << 32;
975 insn++;
976 CONT;
977 ALU64_ARSH_X:
978 (*(s64 *) &DST) >>= SRC;
979 CONT;
980 ALU64_ARSH_K:
981 (*(s64 *) &DST) >>= IMM;
982 CONT;
983 ALU64_MOD_X:
984 div64_u64_rem(DST, SRC, &tmp);
985 DST = tmp;
986 CONT;
987 ALU_MOD_X:
988 tmp = (u32) DST;
989 DST = do_div(tmp, (u32) SRC);
990 CONT;
991 ALU64_MOD_K:
992 div64_u64_rem(DST, IMM, &tmp);
993 DST = tmp;
994 CONT;
995 ALU_MOD_K:
996 tmp = (u32) DST;
997 DST = do_div(tmp, (u32) IMM);
998 CONT;
999 ALU64_DIV_X:
1000 DST = div64_u64(DST, SRC);
1001 CONT;
1002 ALU_DIV_X:
1003 tmp = (u32) DST;
1004 do_div(tmp, (u32) SRC);
1005 DST = (u32) tmp;
1006 CONT;
1007 ALU64_DIV_K:
1008 DST = div64_u64(DST, IMM);
1009 CONT;
1010 ALU_DIV_K:
1011 tmp = (u32) DST;
1012 do_div(tmp, (u32) IMM);
1013 DST = (u32) tmp;
1014 CONT;
1015 ALU_END_TO_BE:
1016 switch (IMM) {
1017 case 16:
1018 DST = (__force u16) cpu_to_be16(DST);
1019 break;
1020 case 32:
1021 DST = (__force u32) cpu_to_be32(DST);
1022 break;
1023 case 64:
1024 DST = (__force u64) cpu_to_be64(DST);
1025 break;
1026 }
1027 CONT;
1028 ALU_END_TO_LE:
1029 switch (IMM) {
1030 case 16:
1031 DST = (__force u16) cpu_to_le16(DST);
1032 break;
1033 case 32:
1034 DST = (__force u32) cpu_to_le32(DST);
1035 break;
1036 case 64:
1037 DST = (__force u64) cpu_to_le64(DST);
1038 break;
1039 }
1040 CONT;
1041
1042 /* CALL */
1043 JMP_CALL:
1044 /* Function call scratches BPF_R1-BPF_R5 registers,
1045 * preserves BPF_R6-BPF_R9, and stores return value
1046 * into BPF_R0.
1047 */
1048 BPF_R0 = (__bpf_call_base + insn->imm)(BPF_R1, BPF_R2, BPF_R3,
1049 BPF_R4, BPF_R5);
1050 CONT;
1051
1052 JMP_CALL_ARGS:
1053 BPF_R0 = (__bpf_call_base_args + insn->imm)(BPF_R1, BPF_R2,
1054 BPF_R3, BPF_R4,
1055 BPF_R5,
1056 insn + insn->off + 1);
1057 CONT;
1058
1059 JMP_TAIL_CALL: {
1060 struct bpf_map *map = (struct bpf_map *) (unsigned long) BPF_R2;
1061 struct bpf_array *array = container_of(map, struct bpf_array, map);
1062 struct bpf_prog *prog;
1063 u32 index = BPF_R3;
1064
1065 if (unlikely(index >= array->map.max_entries))
1066 goto out;
1067 if (unlikely(tail_call_cnt > MAX_TAIL_CALL_CNT))
1068 goto out;
1069
1070 tail_call_cnt++;
1071
1072 prog = READ_ONCE(array->ptrs[index]);
1073 if (!prog)
1074 goto out;
1075
1076 /* ARG1 at this point is guaranteed to point to CTX from
1077 * the verifier side due to the fact that the tail call is
1078 * handeled like a helper, that is, bpf_tail_call_proto,
1079 * where arg1_type is ARG_PTR_TO_CTX.
1080 */
1081 insn = prog->insnsi;
1082 goto select_insn;
1083 out:
1084 CONT;
1085 }
1086 /* JMP */
1087 JMP_JA:
1088 insn += insn->off;
1089 CONT;
1090 JMP_JEQ_X:
1091 if (DST == SRC) {
1092 insn += insn->off;
1093 CONT_JMP;
1094 }
1095 CONT;
1096 JMP_JEQ_K:
1097 if (DST == IMM) {
1098 insn += insn->off;
1099 CONT_JMP;
1100 }
1101 CONT;
1102 JMP_JNE_X:
1103 if (DST != SRC) {
1104 insn += insn->off;
1105 CONT_JMP;
1106 }
1107 CONT;
1108 JMP_JNE_K:
1109 if (DST != IMM) {
1110 insn += insn->off;
1111 CONT_JMP;
1112 }
1113 CONT;
1114 JMP_JGT_X:
1115 if (DST > SRC) {
1116 insn += insn->off;
1117 CONT_JMP;
1118 }
1119 CONT;
1120 JMP_JGT_K:
1121 if (DST > IMM) {
1122 insn += insn->off;
1123 CONT_JMP;
1124 }
1125 CONT;
1126 JMP_JLT_X:
1127 if (DST < SRC) {
1128 insn += insn->off;
1129 CONT_JMP;
1130 }
1131 CONT;
1132 JMP_JLT_K:
1133 if (DST < IMM) {
1134 insn += insn->off;
1135 CONT_JMP;
1136 }
1137 CONT;
1138 JMP_JGE_X:
1139 if (DST >= SRC) {
1140 insn += insn->off;
1141 CONT_JMP;
1142 }
1143 CONT;
1144 JMP_JGE_K:
1145 if (DST >= IMM) {
1146 insn += insn->off;
1147 CONT_JMP;
1148 }
1149 CONT;
1150 JMP_JLE_X:
1151 if (DST <= SRC) {
1152 insn += insn->off;
1153 CONT_JMP;
1154 }
1155 CONT;
1156 JMP_JLE_K:
1157 if (DST <= IMM) {
1158 insn += insn->off;
1159 CONT_JMP;
1160 }
1161 CONT;
1162 JMP_JSGT_X:
1163 if (((s64) DST) > ((s64) SRC)) {
1164 insn += insn->off;
1165 CONT_JMP;
1166 }
1167 CONT;
1168 JMP_JSGT_K:
1169 if (((s64) DST) > ((s64) IMM)) {
1170 insn += insn->off;
1171 CONT_JMP;
1172 }
1173 CONT;
1174 JMP_JSLT_X:
1175 if (((s64) DST) < ((s64) SRC)) {
1176 insn += insn->off;
1177 CONT_JMP;
1178 }
1179 CONT;
1180 JMP_JSLT_K:
1181 if (((s64) DST) < ((s64) IMM)) {
1182 insn += insn->off;
1183 CONT_JMP;
1184 }
1185 CONT;
1186 JMP_JSGE_X:
1187 if (((s64) DST) >= ((s64) SRC)) {
1188 insn += insn->off;
1189 CONT_JMP;
1190 }
1191 CONT;
1192 JMP_JSGE_K:
1193 if (((s64) DST) >= ((s64) IMM)) {
1194 insn += insn->off;
1195 CONT_JMP;
1196 }
1197 CONT;
1198 JMP_JSLE_X:
1199 if (((s64) DST) <= ((s64) SRC)) {
1200 insn += insn->off;
1201 CONT_JMP;
1202 }
1203 CONT;
1204 JMP_JSLE_K:
1205 if (((s64) DST) <= ((s64) IMM)) {
1206 insn += insn->off;
1207 CONT_JMP;
1208 }
1209 CONT;
1210 JMP_JSET_X:
1211 if (DST & SRC) {
1212 insn += insn->off;
1213 CONT_JMP;
1214 }
1215 CONT;
1216 JMP_JSET_K:
1217 if (DST & IMM) {
1218 insn += insn->off;
1219 CONT_JMP;
1220 }
1221 CONT;
1222 JMP_EXIT:
1223 return BPF_R0;
1224
1225 /* STX and ST and LDX*/
1226 #define LDST(SIZEOP, SIZE) \
1227 STX_MEM_##SIZEOP: \
1228 *(SIZE *)(unsigned long) (DST + insn->off) = SRC; \
1229 CONT; \
1230 ST_MEM_##SIZEOP: \
1231 *(SIZE *)(unsigned long) (DST + insn->off) = IMM; \
1232 CONT; \
1233 LDX_MEM_##SIZEOP: \
1234 DST = *(SIZE *)(unsigned long) (SRC + insn->off); \
1235 CONT;
1236
1237 LDST(B, u8)
1238 LDST(H, u16)
1239 LDST(W, u32)
1240 LDST(DW, u64)
1241 #undef LDST
1242 STX_XADD_W: /* lock xadd *(u32 *)(dst_reg + off16) += src_reg */
1243 atomic_add((u32) SRC, (atomic_t *)(unsigned long)
1244 (DST + insn->off));
1245 CONT;
1246 STX_XADD_DW: /* lock xadd *(u64 *)(dst_reg + off16) += src_reg */
1247 atomic64_add((u64) SRC, (atomic64_t *)(unsigned long)
1248 (DST + insn->off));
1249 CONT;
1250
1251 default_label:
1252 /* If we ever reach this, we have a bug somewhere. Die hard here
1253 * instead of just returning 0; we could be somewhere in a subprog,
1254 * so execution could continue otherwise which we do /not/ want.
1255 *
1256 * Note, verifier whitelists all opcodes in bpf_opcode_in_insntable().
1257 */
1258 pr_warn("BPF interpreter: unknown opcode %02x\n", insn->code);
1259 BUG_ON(1);
1260 return 0;
1261 }
1262 STACK_FRAME_NON_STANDARD(___bpf_prog_run); /* jump table */
1263
1264 #define PROG_NAME(stack_size) __bpf_prog_run##stack_size
1265 #define DEFINE_BPF_PROG_RUN(stack_size) \
1266 static unsigned int PROG_NAME(stack_size)(const void *ctx, const struct bpf_insn *insn) \
1267 { \
1268 u64 stack[stack_size / sizeof(u64)]; \
1269 u64 regs[MAX_BPF_REG]; \
1270 \
1271 FP = (u64) (unsigned long) &stack[ARRAY_SIZE(stack)]; \
1272 ARG1 = (u64) (unsigned long) ctx; \
1273 return ___bpf_prog_run(regs, insn, stack); \
1274 }
1275
1276 #define PROG_NAME_ARGS(stack_size) __bpf_prog_run_args##stack_size
1277 #define DEFINE_BPF_PROG_RUN_ARGS(stack_size) \
1278 static u64 PROG_NAME_ARGS(stack_size)(u64 r1, u64 r2, u64 r3, u64 r4, u64 r5, \
1279 const struct bpf_insn *insn) \
1280 { \
1281 u64 stack[stack_size / sizeof(u64)]; \
1282 u64 regs[MAX_BPF_REG]; \
1283 \
1284 FP = (u64) (unsigned long) &stack[ARRAY_SIZE(stack)]; \
1285 BPF_R1 = r1; \
1286 BPF_R2 = r2; \
1287 BPF_R3 = r3; \
1288 BPF_R4 = r4; \
1289 BPF_R5 = r5; \
1290 return ___bpf_prog_run(regs, insn, stack); \
1291 }
1292
1293 #define EVAL1(FN, X) FN(X)
1294 #define EVAL2(FN, X, Y...) FN(X) EVAL1(FN, Y)
1295 #define EVAL3(FN, X, Y...) FN(X) EVAL2(FN, Y)
1296 #define EVAL4(FN, X, Y...) FN(X) EVAL3(FN, Y)
1297 #define EVAL5(FN, X, Y...) FN(X) EVAL4(FN, Y)
1298 #define EVAL6(FN, X, Y...) FN(X) EVAL5(FN, Y)
1299
1300 EVAL6(DEFINE_BPF_PROG_RUN, 32, 64, 96, 128, 160, 192);
1301 EVAL6(DEFINE_BPF_PROG_RUN, 224, 256, 288, 320, 352, 384);
1302 EVAL4(DEFINE_BPF_PROG_RUN, 416, 448, 480, 512);
1303
1304 EVAL6(DEFINE_BPF_PROG_RUN_ARGS, 32, 64, 96, 128, 160, 192);
1305 EVAL6(DEFINE_BPF_PROG_RUN_ARGS, 224, 256, 288, 320, 352, 384);
1306 EVAL4(DEFINE_BPF_PROG_RUN_ARGS, 416, 448, 480, 512);
1307
1308 #define PROG_NAME_LIST(stack_size) PROG_NAME(stack_size),
1309
1310 static unsigned int (*interpreters[])(const void *ctx,
1311 const struct bpf_insn *insn) = {
1312 EVAL6(PROG_NAME_LIST, 32, 64, 96, 128, 160, 192)
1313 EVAL6(PROG_NAME_LIST, 224, 256, 288, 320, 352, 384)
1314 EVAL4(PROG_NAME_LIST, 416, 448, 480, 512)
1315 };
1316 #undef PROG_NAME_LIST
1317 #define PROG_NAME_LIST(stack_size) PROG_NAME_ARGS(stack_size),
1318 static u64 (*interpreters_args[])(u64 r1, u64 r2, u64 r3, u64 r4, u64 r5,
1319 const struct bpf_insn *insn) = {
1320 EVAL6(PROG_NAME_LIST, 32, 64, 96, 128, 160, 192)
1321 EVAL6(PROG_NAME_LIST, 224, 256, 288, 320, 352, 384)
1322 EVAL4(PROG_NAME_LIST, 416, 448, 480, 512)
1323 };
1324 #undef PROG_NAME_LIST
1325
1326 void bpf_patch_call_args(struct bpf_insn *insn, u32 stack_depth)
1327 {
1328 stack_depth = max_t(u32, stack_depth, 1);
1329 insn->off = (s16) insn->imm;
1330 insn->imm = interpreters_args[(round_up(stack_depth, 32) / 32) - 1] -
1331 __bpf_call_base_args;
1332 insn->code = BPF_JMP | BPF_CALL_ARGS;
1333 }
1334
1335 #else
1336 static unsigned int __bpf_prog_ret0_warn(const void *ctx,
1337 const struct bpf_insn *insn)
1338 {
1339 /* If this handler ever gets executed, then BPF_JIT_ALWAYS_ON
1340 * is not working properly, so warn about it!
1341 */
1342 WARN_ON_ONCE(1);
1343 return 0;
1344 }
1345 #endif
1346
1347 bool bpf_prog_array_compatible(struct bpf_array *array,
1348 const struct bpf_prog *fp)
1349 {
1350 if (fp->kprobe_override)
1351 return false;
1352
1353 if (!array->owner_prog_type) {
1354 /* There's no owner yet where we could check for
1355 * compatibility.
1356 */
1357 array->owner_prog_type = fp->type;
1358 array->owner_jited = fp->jited;
1359
1360 return true;
1361 }
1362
1363 return array->owner_prog_type == fp->type &&
1364 array->owner_jited == fp->jited;
1365 }
1366
1367 static int bpf_check_tail_call(const struct bpf_prog *fp)
1368 {
1369 struct bpf_prog_aux *aux = fp->aux;
1370 int i;
1371
1372 for (i = 0; i < aux->used_map_cnt; i++) {
1373 struct bpf_map *map = aux->used_maps[i];
1374 struct bpf_array *array;
1375
1376 if (map->map_type != BPF_MAP_TYPE_PROG_ARRAY)
1377 continue;
1378
1379 array = container_of(map, struct bpf_array, map);
1380 if (!bpf_prog_array_compatible(array, fp))
1381 return -EINVAL;
1382 }
1383
1384 return 0;
1385 }
1386
1387 /**
1388 * bpf_prog_select_runtime - select exec runtime for BPF program
1389 * @fp: bpf_prog populated with internal BPF program
1390 * @err: pointer to error variable
1391 *
1392 * Try to JIT eBPF program, if JIT is not available, use interpreter.
1393 * The BPF program will be executed via BPF_PROG_RUN() macro.
1394 */
1395 struct bpf_prog *bpf_prog_select_runtime(struct bpf_prog *fp, int *err)
1396 {
1397 #ifndef CONFIG_BPF_JIT_ALWAYS_ON
1398 u32 stack_depth = max_t(u32, fp->aux->stack_depth, 1);
1399
1400 fp->bpf_func = interpreters[(round_up(stack_depth, 32) / 32) - 1];
1401 #else
1402 fp->bpf_func = __bpf_prog_ret0_warn;
1403 #endif
1404
1405 /* eBPF JITs can rewrite the program in case constant
1406 * blinding is active. However, in case of error during
1407 * blinding, bpf_int_jit_compile() must always return a
1408 * valid program, which in this case would simply not
1409 * be JITed, but falls back to the interpreter.
1410 */
1411 if (!bpf_prog_is_dev_bound(fp->aux)) {
1412 fp = bpf_int_jit_compile(fp);
1413 #ifdef CONFIG_BPF_JIT_ALWAYS_ON
1414 if (!fp->jited) {
1415 *err = -ENOTSUPP;
1416 return fp;
1417 }
1418 #endif
1419 } else {
1420 *err = bpf_prog_offload_compile(fp);
1421 if (*err)
1422 return fp;
1423 }
1424 bpf_prog_lock_ro(fp);
1425
1426 /* The tail call compatibility check can only be done at
1427 * this late stage as we need to determine, if we deal
1428 * with JITed or non JITed program concatenations and not
1429 * all eBPF JITs might immediately support all features.
1430 */
1431 *err = bpf_check_tail_call(fp);
1432
1433 return fp;
1434 }
1435 EXPORT_SYMBOL_GPL(bpf_prog_select_runtime);
1436
1437 static unsigned int __bpf_prog_ret1(const void *ctx,
1438 const struct bpf_insn *insn)
1439 {
1440 return 1;
1441 }
1442
1443 static struct bpf_prog_dummy {
1444 struct bpf_prog prog;
1445 } dummy_bpf_prog = {
1446 .prog = {
1447 .bpf_func = __bpf_prog_ret1,
1448 },
1449 };
1450
1451 /* to avoid allocating empty bpf_prog_array for cgroups that
1452 * don't have bpf program attached use one global 'empty_prog_array'
1453 * It will not be modified the caller of bpf_prog_array_alloc()
1454 * (since caller requested prog_cnt == 0)
1455 * that pointer should be 'freed' by bpf_prog_array_free()
1456 */
1457 static struct {
1458 struct bpf_prog_array hdr;
1459 struct bpf_prog *null_prog;
1460 } empty_prog_array = {
1461 .null_prog = NULL,
1462 };
1463
1464 struct bpf_prog_array __rcu *bpf_prog_array_alloc(u32 prog_cnt, gfp_t flags)
1465 {
1466 if (prog_cnt)
1467 return kzalloc(sizeof(struct bpf_prog_array) +
1468 sizeof(struct bpf_prog *) * (prog_cnt + 1),
1469 flags);
1470
1471 return &empty_prog_array.hdr;
1472 }
1473
1474 void bpf_prog_array_free(struct bpf_prog_array __rcu *progs)
1475 {
1476 if (!progs ||
1477 progs == (struct bpf_prog_array __rcu *)&empty_prog_array.hdr)
1478 return;
1479 kfree_rcu(progs, rcu);
1480 }
1481
1482 int bpf_prog_array_length(struct bpf_prog_array __rcu *progs)
1483 {
1484 struct bpf_prog **prog;
1485 u32 cnt = 0;
1486
1487 rcu_read_lock();
1488 prog = rcu_dereference(progs)->progs;
1489 for (; *prog; prog++)
1490 if (*prog != &dummy_bpf_prog.prog)
1491 cnt++;
1492 rcu_read_unlock();
1493 return cnt;
1494 }
1495
1496 static bool bpf_prog_array_copy_core(struct bpf_prog **prog,
1497 u32 *prog_ids,
1498 u32 request_cnt)
1499 {
1500 int i = 0;
1501
1502 for (; *prog; prog++) {
1503 if (*prog == &dummy_bpf_prog.prog)
1504 continue;
1505 prog_ids[i] = (*prog)->aux->id;
1506 if (++i == request_cnt) {
1507 prog++;
1508 break;
1509 }
1510 }
1511
1512 return !!(*prog);
1513 }
1514
1515 int bpf_prog_array_copy_to_user(struct bpf_prog_array __rcu *progs,
1516 __u32 __user *prog_ids, u32 cnt)
1517 {
1518 struct bpf_prog **prog;
1519 unsigned long err = 0;
1520 bool nospc;
1521 u32 *ids;
1522
1523 /* users of this function are doing:
1524 * cnt = bpf_prog_array_length();
1525 * if (cnt > 0)
1526 * bpf_prog_array_copy_to_user(..., cnt);
1527 * so below kcalloc doesn't need extra cnt > 0 check, but
1528 * bpf_prog_array_length() releases rcu lock and
1529 * prog array could have been swapped with empty or larger array,
1530 * so always copy 'cnt' prog_ids to the user.
1531 * In a rare race the user will see zero prog_ids
1532 */
1533 ids = kcalloc(cnt, sizeof(u32), GFP_USER | __GFP_NOWARN);
1534 if (!ids)
1535 return -ENOMEM;
1536 rcu_read_lock();
1537 prog = rcu_dereference(progs)->progs;
1538 nospc = bpf_prog_array_copy_core(prog, ids, cnt);
1539 rcu_read_unlock();
1540 err = copy_to_user(prog_ids, ids, cnt * sizeof(u32));
1541 kfree(ids);
1542 if (err)
1543 return -EFAULT;
1544 if (nospc)
1545 return -ENOSPC;
1546 return 0;
1547 }
1548
1549 void bpf_prog_array_delete_safe(struct bpf_prog_array __rcu *progs,
1550 struct bpf_prog *old_prog)
1551 {
1552 struct bpf_prog **prog = progs->progs;
1553
1554 for (; *prog; prog++)
1555 if (*prog == old_prog) {
1556 WRITE_ONCE(*prog, &dummy_bpf_prog.prog);
1557 break;
1558 }
1559 }
1560
1561 int bpf_prog_array_copy(struct bpf_prog_array __rcu *old_array,
1562 struct bpf_prog *exclude_prog,
1563 struct bpf_prog *include_prog,
1564 struct bpf_prog_array **new_array)
1565 {
1566 int new_prog_cnt, carry_prog_cnt = 0;
1567 struct bpf_prog **existing_prog;
1568 struct bpf_prog_array *array;
1569 int new_prog_idx = 0;
1570
1571 /* Figure out how many existing progs we need to carry over to
1572 * the new array.
1573 */
1574 if (old_array) {
1575 existing_prog = old_array->progs;
1576 for (; *existing_prog; existing_prog++) {
1577 if (*existing_prog != exclude_prog &&
1578 *existing_prog != &dummy_bpf_prog.prog)
1579 carry_prog_cnt++;
1580 if (*existing_prog == include_prog)
1581 return -EEXIST;
1582 }
1583 }
1584
1585 /* How many progs (not NULL) will be in the new array? */
1586 new_prog_cnt = carry_prog_cnt;
1587 if (include_prog)
1588 new_prog_cnt += 1;
1589
1590 /* Do we have any prog (not NULL) in the new array? */
1591 if (!new_prog_cnt) {
1592 *new_array = NULL;
1593 return 0;
1594 }
1595
1596 /* +1 as the end of prog_array is marked with NULL */
1597 array = bpf_prog_array_alloc(new_prog_cnt + 1, GFP_KERNEL);
1598 if (!array)
1599 return -ENOMEM;
1600
1601 /* Fill in the new prog array */
1602 if (carry_prog_cnt) {
1603 existing_prog = old_array->progs;
1604 for (; *existing_prog; existing_prog++)
1605 if (*existing_prog != exclude_prog &&
1606 *existing_prog != &dummy_bpf_prog.prog)
1607 array->progs[new_prog_idx++] = *existing_prog;
1608 }
1609 if (include_prog)
1610 array->progs[new_prog_idx++] = include_prog;
1611 array->progs[new_prog_idx] = NULL;
1612 *new_array = array;
1613 return 0;
1614 }
1615
1616 int bpf_prog_array_copy_info(struct bpf_prog_array __rcu *array,
1617 u32 *prog_ids, u32 request_cnt,
1618 u32 *prog_cnt)
1619 {
1620 struct bpf_prog **prog;
1621 u32 cnt = 0;
1622
1623 if (array)
1624 cnt = bpf_prog_array_length(array);
1625
1626 *prog_cnt = cnt;
1627
1628 /* return early if user requested only program count or nothing to copy */
1629 if (!request_cnt || !cnt)
1630 return 0;
1631
1632 /* this function is called under trace/bpf_trace.c: bpf_event_mutex */
1633 prog = rcu_dereference_check(array, 1)->progs;
1634 return bpf_prog_array_copy_core(prog, prog_ids, request_cnt) ? -ENOSPC
1635 : 0;
1636 }
1637
1638 static void bpf_prog_free_deferred(struct work_struct *work)
1639 {
1640 struct bpf_prog_aux *aux;
1641 int i;
1642
1643 aux = container_of(work, struct bpf_prog_aux, work);
1644 if (bpf_prog_is_dev_bound(aux))
1645 bpf_prog_offload_destroy(aux->prog);
1646 #ifdef CONFIG_PERF_EVENTS
1647 if (aux->prog->has_callchain_buf)
1648 put_callchain_buffers();
1649 #endif
1650 for (i = 0; i < aux->func_cnt; i++)
1651 bpf_jit_free(aux->func[i]);
1652 if (aux->func_cnt) {
1653 kfree(aux->func);
1654 bpf_prog_unlock_free(aux->prog);
1655 } else {
1656 bpf_jit_free(aux->prog);
1657 }
1658 }
1659
1660 /* Free internal BPF program */
1661 void bpf_prog_free(struct bpf_prog *fp)
1662 {
1663 struct bpf_prog_aux *aux = fp->aux;
1664
1665 INIT_WORK(&aux->work, bpf_prog_free_deferred);
1666 schedule_work(&aux->work);
1667 }
1668 EXPORT_SYMBOL_GPL(bpf_prog_free);
1669
1670 /* RNG for unpriviledged user space with separated state from prandom_u32(). */
1671 static DEFINE_PER_CPU(struct rnd_state, bpf_user_rnd_state);
1672
1673 void bpf_user_rnd_init_once(void)
1674 {
1675 prandom_init_once(&bpf_user_rnd_state);
1676 }
1677
1678 BPF_CALL_0(bpf_user_rnd_u32)
1679 {
1680 /* Should someone ever have the rather unwise idea to use some
1681 * of the registers passed into this function, then note that
1682 * this function is called from native eBPF and classic-to-eBPF
1683 * transformations. Register assignments from both sides are
1684 * different, f.e. classic always sets fn(ctx, A, X) here.
1685 */
1686 struct rnd_state *state;
1687 u32 res;
1688
1689 state = &get_cpu_var(bpf_user_rnd_state);
1690 res = prandom_u32_state(state);
1691 put_cpu_var(bpf_user_rnd_state);
1692
1693 return res;
1694 }
1695
1696 /* Weak definitions of helper functions in case we don't have bpf syscall. */
1697 const struct bpf_func_proto bpf_map_lookup_elem_proto __weak;
1698 const struct bpf_func_proto bpf_map_update_elem_proto __weak;
1699 const struct bpf_func_proto bpf_map_delete_elem_proto __weak;
1700
1701 const struct bpf_func_proto bpf_get_prandom_u32_proto __weak;
1702 const struct bpf_func_proto bpf_get_smp_processor_id_proto __weak;
1703 const struct bpf_func_proto bpf_get_numa_node_id_proto __weak;
1704 const struct bpf_func_proto bpf_ktime_get_ns_proto __weak;
1705
1706 const struct bpf_func_proto bpf_get_current_pid_tgid_proto __weak;
1707 const struct bpf_func_proto bpf_get_current_uid_gid_proto __weak;
1708 const struct bpf_func_proto bpf_get_current_comm_proto __weak;
1709 const struct bpf_func_proto bpf_sock_map_update_proto __weak;
1710
1711 const struct bpf_func_proto * __weak bpf_get_trace_printk_proto(void)
1712 {
1713 return NULL;
1714 }
1715
1716 u64 __weak
1717 bpf_event_output(struct bpf_map *map, u64 flags, void *meta, u64 meta_size,
1718 void *ctx, u64 ctx_size, bpf_ctx_copy_t ctx_copy)
1719 {
1720 return -ENOTSUPP;
1721 }
1722
1723 /* Always built-in helper functions. */
1724 const struct bpf_func_proto bpf_tail_call_proto = {
1725 .func = NULL,
1726 .gpl_only = false,
1727 .ret_type = RET_VOID,
1728 .arg1_type = ARG_PTR_TO_CTX,
1729 .arg2_type = ARG_CONST_MAP_PTR,
1730 .arg3_type = ARG_ANYTHING,
1731 };
1732
1733 /* Stub for JITs that only support cBPF. eBPF programs are interpreted.
1734 * It is encouraged to implement bpf_int_jit_compile() instead, so that
1735 * eBPF and implicitly also cBPF can get JITed!
1736 */
1737 struct bpf_prog * __weak bpf_int_jit_compile(struct bpf_prog *prog)
1738 {
1739 return prog;
1740 }
1741
1742 /* Stub for JITs that support eBPF. All cBPF code gets transformed into
1743 * eBPF by the kernel and is later compiled by bpf_int_jit_compile().
1744 */
1745 void __weak bpf_jit_compile(struct bpf_prog *prog)
1746 {
1747 }
1748
1749 bool __weak bpf_helper_changes_pkt_data(void *func)
1750 {
1751 return false;
1752 }
1753
1754 /* To execute LD_ABS/LD_IND instructions __bpf_prog_run() may call
1755 * skb_copy_bits(), so provide a weak definition of it for NET-less config.
1756 */
1757 int __weak skb_copy_bits(const struct sk_buff *skb, int offset, void *to,
1758 int len)
1759 {
1760 return -EFAULT;
1761 }
1762
1763 /* All definitions of tracepoints related to BPF. */
1764 #define CREATE_TRACE_POINTS
1765 #include <linux/bpf_trace.h>
1766
1767 EXPORT_TRACEPOINT_SYMBOL_GPL(xdp_exception);
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