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 int bpf_adj_delta_to_imm(struct bpf_insn *insn, u32 pos, u32 delta, 223 u32 curr, const bool probe_pass) 224 { 225 const s64 imm_min = S32_MIN, imm_max = S32_MAX; 226 s64 imm = insn->imm; 227 228 if (curr < pos && curr + imm + 1 > pos) 229 imm += delta; 230 else if (curr > pos + delta && curr + imm + 1 <= pos + delta) 231 imm -= delta; 232 if (imm < imm_min || imm > imm_max) 233 return -ERANGE; 234 if (!probe_pass) 235 insn->imm = imm; 236 return 0; 237 } 238 239 static int bpf_adj_delta_to_off(struct bpf_insn *insn, u32 pos, u32 delta, 240 u32 curr, const bool probe_pass) 241 { 242 const s32 off_min = S16_MIN, off_max = S16_MAX; 243 s32 off = insn->off; 244 245 if (curr < pos && curr + off + 1 > pos) 246 off += delta; 247 else if (curr > pos + delta && curr + off + 1 <= pos + delta) 248 off -= delta; 249 if (off < off_min || off > off_max) 250 return -ERANGE; 251 if (!probe_pass) 252 insn->off = off; 253 return 0; 254 } 255 256 static int bpf_adj_branches(struct bpf_prog *prog, u32 pos, u32 delta, 257 const bool probe_pass) 258 { 259 u32 i, insn_cnt = prog->len + (probe_pass ? delta : 0); 260 struct bpf_insn *insn = prog->insnsi; 261 int ret = 0; 262 263 for (i = 0; i < insn_cnt; i++, insn++) { 264 u8 code; 265 266 /* In the probing pass we still operate on the original, 267 * unpatched image in order to check overflows before we 268 * do any other adjustments. Therefore skip the patchlet. 269 */ 270 if (probe_pass && i == pos) { 271 i += delta + 1; 272 insn++; 273 } 274 code = insn->code; 275 if (BPF_CLASS(code) != BPF_JMP || 276 BPF_OP(code) == BPF_EXIT) 277 continue; 278 /* Adjust offset of jmps if we cross patch boundaries. */ 279 if (BPF_OP(code) == BPF_CALL) { 280 if (insn->src_reg != BPF_PSEUDO_CALL) 281 continue; 282 ret = bpf_adj_delta_to_imm(insn, pos, delta, i, 283 probe_pass); 284 } else { 285 ret = bpf_adj_delta_to_off(insn, pos, delta, i, 286 probe_pass); 287 } 288 if (ret) 289 break; 290 } 291 292 return ret; 293 } 294 295 struct bpf_prog *bpf_patch_insn_single(struct bpf_prog *prog, u32 off, 296 const struct bpf_insn *patch, u32 len) 297 { 298 u32 insn_adj_cnt, insn_rest, insn_delta = len - 1; 299 const u32 cnt_max = S16_MAX; 300 struct bpf_prog *prog_adj; 301 302 /* Since our patchlet doesn't expand the image, we're done. */ 303 if (insn_delta == 0) { 304 memcpy(prog->insnsi + off, patch, sizeof(*patch)); 305 return prog; 306 } 307 308 insn_adj_cnt = prog->len + insn_delta; 309 310 /* Reject anything that would potentially let the insn->off 311 * target overflow when we have excessive program expansions. 312 * We need to probe here before we do any reallocation where 313 * we afterwards may not fail anymore. 314 */ 315 if (insn_adj_cnt > cnt_max && 316 bpf_adj_branches(prog, off, insn_delta, true)) 317 return NULL; 318 319 /* Several new instructions need to be inserted. Make room 320 * for them. Likely, there's no need for a new allocation as 321 * last page could have large enough tailroom. 322 */ 323 prog_adj = bpf_prog_realloc(prog, bpf_prog_size(insn_adj_cnt), 324 GFP_USER); 325 if (!prog_adj) 326 return NULL; 327 328 prog_adj->len = insn_adj_cnt; 329 330 /* Patching happens in 3 steps: 331 * 332 * 1) Move over tail of insnsi from next instruction onwards, 333 * so we can patch the single target insn with one or more 334 * new ones (patching is always from 1 to n insns, n > 0). 335 * 2) Inject new instructions at the target location. 336 * 3) Adjust branch offsets if necessary. 337 */ 338 insn_rest = insn_adj_cnt - off - len; 339 340 memmove(prog_adj->insnsi + off + len, prog_adj->insnsi + off + 1, 341 sizeof(*patch) * insn_rest); 342 memcpy(prog_adj->insnsi + off, patch, sizeof(*patch) * len); 343 344 /* We are guaranteed to not fail at this point, otherwise 345 * the ship has sailed to reverse to the original state. An 346 * overflow cannot happen at this point. 347 */ 348 BUG_ON(bpf_adj_branches(prog_adj, off, insn_delta, false)); 349 350 return prog_adj; 351 } 352 353 void bpf_prog_kallsyms_del_subprogs(struct bpf_prog *fp) 354 { 355 int i; 356 357 for (i = 0; i < fp->aux->func_cnt; i++) 358 bpf_prog_kallsyms_del(fp->aux->func[i]); 359 } 360 361 void bpf_prog_kallsyms_del_all(struct bpf_prog *fp) 362 { 363 bpf_prog_kallsyms_del_subprogs(fp); 364 bpf_prog_kallsyms_del(fp); 365 } 366 367 #ifdef CONFIG_BPF_JIT 368 # define BPF_JIT_LIMIT_DEFAULT (PAGE_SIZE * 40000) 369 370 /* All BPF JIT sysctl knobs here. */ 371 int bpf_jit_enable __read_mostly = IS_BUILTIN(CONFIG_BPF_JIT_ALWAYS_ON); 372 int bpf_jit_harden __read_mostly; 373 int bpf_jit_kallsyms __read_mostly; 374 int bpf_jit_limit __read_mostly = BPF_JIT_LIMIT_DEFAULT; 375 376 static __always_inline void 377 bpf_get_prog_addr_region(const struct bpf_prog *prog, 378 unsigned long *symbol_start, 379 unsigned long *symbol_end) 380 { 381 const struct bpf_binary_header *hdr = bpf_jit_binary_hdr(prog); 382 unsigned long addr = (unsigned long)hdr; 383 384 WARN_ON_ONCE(!bpf_prog_ebpf_jited(prog)); 385 386 *symbol_start = addr; 387 *symbol_end = addr + hdr->pages * PAGE_SIZE; 388 } 389 390 static void bpf_get_prog_name(const struct bpf_prog *prog, char *sym) 391 { 392 const char *end = sym + KSYM_NAME_LEN; 393 394 BUILD_BUG_ON(sizeof("bpf_prog_") + 395 sizeof(prog->tag) * 2 + 396 /* name has been null terminated. 397 * We should need +1 for the '_' preceding 398 * the name. However, the null character 399 * is double counted between the name and the 400 * sizeof("bpf_prog_") above, so we omit 401 * the +1 here. 402 */ 403 sizeof(prog->aux->name) > KSYM_NAME_LEN); 404 405 sym += snprintf(sym, KSYM_NAME_LEN, "bpf_prog_"); 406 sym = bin2hex(sym, prog->tag, sizeof(prog->tag)); 407 if (prog->aux->name[0]) 408 snprintf(sym, (size_t)(end - sym), "_%s", prog->aux->name); 409 else 410 *sym = 0; 411 } 412 413 static __always_inline unsigned long 414 bpf_get_prog_addr_start(struct latch_tree_node *n) 415 { 416 unsigned long symbol_start, symbol_end; 417 const struct bpf_prog_aux *aux; 418 419 aux = container_of(n, struct bpf_prog_aux, ksym_tnode); 420 bpf_get_prog_addr_region(aux->prog, &symbol_start, &symbol_end); 421 422 return symbol_start; 423 } 424 425 static __always_inline bool bpf_tree_less(struct latch_tree_node *a, 426 struct latch_tree_node *b) 427 { 428 return bpf_get_prog_addr_start(a) < bpf_get_prog_addr_start(b); 429 } 430 431 static __always_inline int bpf_tree_comp(void *key, struct latch_tree_node *n) 432 { 433 unsigned long val = (unsigned long)key; 434 unsigned long symbol_start, symbol_end; 435 const struct bpf_prog_aux *aux; 436 437 aux = container_of(n, struct bpf_prog_aux, ksym_tnode); 438 bpf_get_prog_addr_region(aux->prog, &symbol_start, &symbol_end); 439 440 if (val < symbol_start) 441 return -1; 442 if (val >= symbol_end) 443 return 1; 444 445 return 0; 446 } 447 448 static const struct latch_tree_ops bpf_tree_ops = { 449 .less = bpf_tree_less, 450 .comp = bpf_tree_comp, 451 }; 452 453 static DEFINE_SPINLOCK(bpf_lock); 454 static LIST_HEAD(bpf_kallsyms); 455 static struct latch_tree_root bpf_tree __cacheline_aligned; 456 457 static void bpf_prog_ksym_node_add(struct bpf_prog_aux *aux) 458 { 459 WARN_ON_ONCE(!list_empty(&aux->ksym_lnode)); 460 list_add_tail_rcu(&aux->ksym_lnode, &bpf_kallsyms); 461 latch_tree_insert(&aux->ksym_tnode, &bpf_tree, &bpf_tree_ops); 462 } 463 464 static void bpf_prog_ksym_node_del(struct bpf_prog_aux *aux) 465 { 466 if (list_empty(&aux->ksym_lnode)) 467 return; 468 469 latch_tree_erase(&aux->ksym_tnode, &bpf_tree, &bpf_tree_ops); 470 list_del_rcu(&aux->ksym_lnode); 471 } 472 473 static bool bpf_prog_kallsyms_candidate(const struct bpf_prog *fp) 474 { 475 return fp->jited && !bpf_prog_was_classic(fp); 476 } 477 478 static bool bpf_prog_kallsyms_verify_off(const struct bpf_prog *fp) 479 { 480 return list_empty(&fp->aux->ksym_lnode) || 481 fp->aux->ksym_lnode.prev == LIST_POISON2; 482 } 483 484 void bpf_prog_kallsyms_add(struct bpf_prog *fp) 485 { 486 if (!bpf_prog_kallsyms_candidate(fp) || 487 !capable(CAP_SYS_ADMIN)) 488 return; 489 490 spin_lock_bh(&bpf_lock); 491 bpf_prog_ksym_node_add(fp->aux); 492 spin_unlock_bh(&bpf_lock); 493 } 494 495 void bpf_prog_kallsyms_del(struct bpf_prog *fp) 496 { 497 if (!bpf_prog_kallsyms_candidate(fp)) 498 return; 499 500 spin_lock_bh(&bpf_lock); 501 bpf_prog_ksym_node_del(fp->aux); 502 spin_unlock_bh(&bpf_lock); 503 } 504 505 static struct bpf_prog *bpf_prog_kallsyms_find(unsigned long addr) 506 { 507 struct latch_tree_node *n; 508 509 if (!bpf_jit_kallsyms_enabled()) 510 return NULL; 511 512 n = latch_tree_find((void *)addr, &bpf_tree, &bpf_tree_ops); 513 return n ? 514 container_of(n, struct bpf_prog_aux, ksym_tnode)->prog : 515 NULL; 516 } 517 518 const char *__bpf_address_lookup(unsigned long addr, unsigned long *size, 519 unsigned long *off, char *sym) 520 { 521 unsigned long symbol_start, symbol_end; 522 struct bpf_prog *prog; 523 char *ret = NULL; 524 525 rcu_read_lock(); 526 prog = bpf_prog_kallsyms_find(addr); 527 if (prog) { 528 bpf_get_prog_addr_region(prog, &symbol_start, &symbol_end); 529 bpf_get_prog_name(prog, sym); 530 531 ret = sym; 532 if (size) 533 *size = symbol_end - symbol_start; 534 if (off) 535 *off = addr - symbol_start; 536 } 537 rcu_read_unlock(); 538 539 return ret; 540 } 541 542 bool is_bpf_text_address(unsigned long addr) 543 { 544 bool ret; 545 546 rcu_read_lock(); 547 ret = bpf_prog_kallsyms_find(addr) != NULL; 548 rcu_read_unlock(); 549 550 return ret; 551 } 552 553 int bpf_get_kallsym(unsigned int symnum, unsigned long *value, char *type, 554 char *sym) 555 { 556 struct bpf_prog_aux *aux; 557 unsigned int it = 0; 558 int ret = -ERANGE; 559 560 if (!bpf_jit_kallsyms_enabled()) 561 return ret; 562 563 rcu_read_lock(); 564 list_for_each_entry_rcu(aux, &bpf_kallsyms, ksym_lnode) { 565 if (it++ != symnum) 566 continue; 567 568 bpf_get_prog_name(aux->prog, sym); 569 570 *value = (unsigned long)aux->prog->bpf_func; 571 *type = BPF_SYM_ELF_TYPE; 572 573 ret = 0; 574 break; 575 } 576 rcu_read_unlock(); 577 578 return ret; 579 } 580 581 static atomic_long_t bpf_jit_current; 582 583 #if defined(MODULES_VADDR) 584 static int __init bpf_jit_charge_init(void) 585 { 586 /* Only used as heuristic here to derive limit. */ 587 bpf_jit_limit = min_t(u64, round_up((MODULES_END - MODULES_VADDR) >> 2, 588 PAGE_SIZE), INT_MAX); 589 return 0; 590 } 591 pure_initcall(bpf_jit_charge_init); 592 #endif 593 594 static int bpf_jit_charge_modmem(u32 pages) 595 { 596 if (atomic_long_add_return(pages, &bpf_jit_current) > 597 (bpf_jit_limit >> PAGE_SHIFT)) { 598 if (!capable(CAP_SYS_ADMIN)) { 599 atomic_long_sub(pages, &bpf_jit_current); 600 return -EPERM; 601 } 602 } 603 604 return 0; 605 } 606 607 static void bpf_jit_uncharge_modmem(u32 pages) 608 { 609 atomic_long_sub(pages, &bpf_jit_current); 610 } 611 612 struct bpf_binary_header * 613 bpf_jit_binary_alloc(unsigned int proglen, u8 **image_ptr, 614 unsigned int alignment, 615 bpf_jit_fill_hole_t bpf_fill_ill_insns) 616 { 617 struct bpf_binary_header *hdr; 618 u32 size, hole, start, pages; 619 620 /* Most of BPF filters are really small, but if some of them 621 * fill a page, allow at least 128 extra bytes to insert a 622 * random section of illegal instructions. 623 */ 624 size = round_up(proglen + sizeof(*hdr) + 128, PAGE_SIZE); 625 pages = size / PAGE_SIZE; 626 627 if (bpf_jit_charge_modmem(pages)) 628 return NULL; 629 hdr = module_alloc(size); 630 if (!hdr) { 631 bpf_jit_uncharge_modmem(pages); 632 return NULL; 633 } 634 635 /* Fill space with illegal/arch-dep instructions. */ 636 bpf_fill_ill_insns(hdr, size); 637 638 hdr->pages = pages; 639 hole = min_t(unsigned int, size - (proglen + sizeof(*hdr)), 640 PAGE_SIZE - sizeof(*hdr)); 641 start = (get_random_int() % hole) & ~(alignment - 1); 642 643 /* Leave a random number of instructions before BPF code. */ 644 *image_ptr = &hdr->image[start]; 645 646 return hdr; 647 } 648 649 void bpf_jit_binary_free(struct bpf_binary_header *hdr) 650 { 651 u32 pages = hdr->pages; 652 653 module_memfree(hdr); 654 bpf_jit_uncharge_modmem(pages); 655 } 656 657 /* This symbol is only overridden by archs that have different 658 * requirements than the usual eBPF JITs, f.e. when they only 659 * implement cBPF JIT, do not set images read-only, etc. 660 */ 661 void __weak bpf_jit_free(struct bpf_prog *fp) 662 { 663 if (fp->jited) { 664 struct bpf_binary_header *hdr = bpf_jit_binary_hdr(fp); 665 666 bpf_jit_binary_unlock_ro(hdr); 667 bpf_jit_binary_free(hdr); 668 669 WARN_ON_ONCE(!bpf_prog_kallsyms_verify_off(fp)); 670 } 671 672 bpf_prog_unlock_free(fp); 673 } 674 675 int bpf_jit_get_func_addr(const struct bpf_prog *prog, 676 const struct bpf_insn *insn, bool extra_pass, 677 u64 *func_addr, bool *func_addr_fixed) 678 { 679 s16 off = insn->off; 680 s32 imm = insn->imm; 681 u8 *addr; 682 683 *func_addr_fixed = insn->src_reg != BPF_PSEUDO_CALL; 684 if (!*func_addr_fixed) { 685 /* Place-holder address till the last pass has collected 686 * all addresses for JITed subprograms in which case we 687 * can pick them up from prog->aux. 688 */ 689 if (!extra_pass) 690 addr = NULL; 691 else if (prog->aux->func && 692 off >= 0 && off < prog->aux->func_cnt) 693 addr = (u8 *)prog->aux->func[off]->bpf_func; 694 else 695 return -EINVAL; 696 } else { 697 /* Address of a BPF helper call. Since part of the core 698 * kernel, it's always at a fixed location. __bpf_call_base 699 * and the helper with imm relative to it are both in core 700 * kernel. 701 */ 702 addr = (u8 *)__bpf_call_base + imm; 703 } 704 705 *func_addr = (unsigned long)addr; 706 return 0; 707 } 708 709 static int bpf_jit_blind_insn(const struct bpf_insn *from, 710 const struct bpf_insn *aux, 711 struct bpf_insn *to_buff) 712 { 713 struct bpf_insn *to = to_buff; 714 u32 imm_rnd = get_random_int(); 715 s16 off; 716 717 BUILD_BUG_ON(BPF_REG_AX + 1 != MAX_BPF_JIT_REG); 718 BUILD_BUG_ON(MAX_BPF_REG + 1 != MAX_BPF_JIT_REG); 719 720 if (from->imm == 0 && 721 (from->code == (BPF_ALU | BPF_MOV | BPF_K) || 722 from->code == (BPF_ALU64 | BPF_MOV | BPF_K))) { 723 *to++ = BPF_ALU64_REG(BPF_XOR, from->dst_reg, from->dst_reg); 724 goto out; 725 } 726 727 switch (from->code) { 728 case BPF_ALU | BPF_ADD | BPF_K: 729 case BPF_ALU | BPF_SUB | BPF_K: 730 case BPF_ALU | BPF_AND | BPF_K: 731 case BPF_ALU | BPF_OR | BPF_K: 732 case BPF_ALU | BPF_XOR | BPF_K: 733 case BPF_ALU | BPF_MUL | BPF_K: 734 case BPF_ALU | BPF_MOV | BPF_K: 735 case BPF_ALU | BPF_DIV | BPF_K: 736 case BPF_ALU | BPF_MOD | BPF_K: 737 *to++ = BPF_ALU32_IMM(BPF_MOV, BPF_REG_AX, imm_rnd ^ from->imm); 738 *to++ = BPF_ALU32_IMM(BPF_XOR, BPF_REG_AX, imm_rnd); 739 *to++ = BPF_ALU32_REG(from->code, from->dst_reg, BPF_REG_AX); 740 break; 741 742 case BPF_ALU64 | BPF_ADD | BPF_K: 743 case BPF_ALU64 | BPF_SUB | BPF_K: 744 case BPF_ALU64 | BPF_AND | BPF_K: 745 case BPF_ALU64 | BPF_OR | BPF_K: 746 case BPF_ALU64 | BPF_XOR | BPF_K: 747 case BPF_ALU64 | BPF_MUL | BPF_K: 748 case BPF_ALU64 | BPF_MOV | BPF_K: 749 case BPF_ALU64 | BPF_DIV | BPF_K: 750 case BPF_ALU64 | BPF_MOD | BPF_K: 751 *to++ = BPF_ALU64_IMM(BPF_MOV, BPF_REG_AX, imm_rnd ^ from->imm); 752 *to++ = BPF_ALU64_IMM(BPF_XOR, BPF_REG_AX, imm_rnd); 753 *to++ = BPF_ALU64_REG(from->code, from->dst_reg, BPF_REG_AX); 754 break; 755 756 case BPF_JMP | BPF_JEQ | BPF_K: 757 case BPF_JMP | BPF_JNE | BPF_K: 758 case BPF_JMP | BPF_JGT | BPF_K: 759 case BPF_JMP | BPF_JLT | BPF_K: 760 case BPF_JMP | BPF_JGE | BPF_K: 761 case BPF_JMP | BPF_JLE | BPF_K: 762 case BPF_JMP | BPF_JSGT | BPF_K: 763 case BPF_JMP | BPF_JSLT | BPF_K: 764 case BPF_JMP | BPF_JSGE | BPF_K: 765 case BPF_JMP | BPF_JSLE | BPF_K: 766 case BPF_JMP | BPF_JSET | BPF_K: 767 /* Accommodate for extra offset in case of a backjump. */ 768 off = from->off; 769 if (off < 0) 770 off -= 2; 771 *to++ = BPF_ALU64_IMM(BPF_MOV, BPF_REG_AX, imm_rnd ^ from->imm); 772 *to++ = BPF_ALU64_IMM(BPF_XOR, BPF_REG_AX, imm_rnd); 773 *to++ = BPF_JMP_REG(from->code, from->dst_reg, BPF_REG_AX, off); 774 break; 775 776 case BPF_LD | BPF_IMM | BPF_DW: 777 *to++ = BPF_ALU64_IMM(BPF_MOV, BPF_REG_AX, imm_rnd ^ aux[1].imm); 778 *to++ = BPF_ALU64_IMM(BPF_XOR, BPF_REG_AX, imm_rnd); 779 *to++ = BPF_ALU64_IMM(BPF_LSH, BPF_REG_AX, 32); 780 *to++ = BPF_ALU64_REG(BPF_MOV, aux[0].dst_reg, BPF_REG_AX); 781 break; 782 case 0: /* Part 2 of BPF_LD | BPF_IMM | BPF_DW. */ 783 *to++ = BPF_ALU32_IMM(BPF_MOV, BPF_REG_AX, imm_rnd ^ aux[0].imm); 784 *to++ = BPF_ALU32_IMM(BPF_XOR, BPF_REG_AX, imm_rnd); 785 *to++ = BPF_ALU64_REG(BPF_OR, aux[0].dst_reg, BPF_REG_AX); 786 break; 787 788 case BPF_ST | BPF_MEM | BPF_DW: 789 case BPF_ST | BPF_MEM | BPF_W: 790 case BPF_ST | BPF_MEM | BPF_H: 791 case BPF_ST | BPF_MEM | BPF_B: 792 *to++ = BPF_ALU64_IMM(BPF_MOV, BPF_REG_AX, imm_rnd ^ from->imm); 793 *to++ = BPF_ALU64_IMM(BPF_XOR, BPF_REG_AX, imm_rnd); 794 *to++ = BPF_STX_MEM(from->code, from->dst_reg, BPF_REG_AX, from->off); 795 break; 796 } 797 out: 798 return to - to_buff; 799 } 800 801 static struct bpf_prog *bpf_prog_clone_create(struct bpf_prog *fp_other, 802 gfp_t gfp_extra_flags) 803 { 804 gfp_t gfp_flags = GFP_KERNEL | __GFP_ZERO | gfp_extra_flags; 805 struct bpf_prog *fp; 806 807 fp = __vmalloc(fp_other->pages * PAGE_SIZE, gfp_flags, PAGE_KERNEL); 808 if (fp != NULL) { 809 /* aux->prog still points to the fp_other one, so 810 * when promoting the clone to the real program, 811 * this still needs to be adapted. 812 */ 813 memcpy(fp, fp_other, fp_other->pages * PAGE_SIZE); 814 } 815 816 return fp; 817 } 818 819 static void bpf_prog_clone_free(struct bpf_prog *fp) 820 { 821 /* aux was stolen by the other clone, so we cannot free 822 * it from this path! It will be freed eventually by the 823 * other program on release. 824 * 825 * At this point, we don't need a deferred release since 826 * clone is guaranteed to not be locked. 827 */ 828 fp->aux = NULL; 829 __bpf_prog_free(fp); 830 } 831 832 void bpf_jit_prog_release_other(struct bpf_prog *fp, struct bpf_prog *fp_other) 833 { 834 /* We have to repoint aux->prog to self, as we don't 835 * know whether fp here is the clone or the original. 836 */ 837 fp->aux->prog = fp; 838 bpf_prog_clone_free(fp_other); 839 } 840 841 struct bpf_prog *bpf_jit_blind_constants(struct bpf_prog *prog) 842 { 843 struct bpf_insn insn_buff[16], aux[2]; 844 struct bpf_prog *clone, *tmp; 845 int insn_delta, insn_cnt; 846 struct bpf_insn *insn; 847 int i, rewritten; 848 849 if (!bpf_jit_blinding_enabled(prog) || prog->blinded) 850 return prog; 851 852 clone = bpf_prog_clone_create(prog, GFP_USER); 853 if (!clone) 854 return ERR_PTR(-ENOMEM); 855 856 insn_cnt = clone->len; 857 insn = clone->insnsi; 858 859 for (i = 0; i < insn_cnt; i++, insn++) { 860 /* We temporarily need to hold the original ld64 insn 861 * so that we can still access the first part in the 862 * second blinding run. 863 */ 864 if (insn[0].code == (BPF_LD | BPF_IMM | BPF_DW) && 865 insn[1].code == 0) 866 memcpy(aux, insn, sizeof(aux)); 867 868 rewritten = bpf_jit_blind_insn(insn, aux, insn_buff); 869 if (!rewritten) 870 continue; 871 872 tmp = bpf_patch_insn_single(clone, i, insn_buff, rewritten); 873 if (!tmp) { 874 /* Patching may have repointed aux->prog during 875 * realloc from the original one, so we need to 876 * fix it up here on error. 877 */ 878 bpf_jit_prog_release_other(prog, clone); 879 return ERR_PTR(-ENOMEM); 880 } 881 882 clone = tmp; 883 insn_delta = rewritten - 1; 884 885 /* Walk new program and skip insns we just inserted. */ 886 insn = clone->insnsi + i + insn_delta; 887 insn_cnt += insn_delta; 888 i += insn_delta; 889 } 890 891 clone->blinded = 1; 892 return clone; 893 } 894 #endif /* CONFIG_BPF_JIT */ 895 896 /* Base function for offset calculation. Needs to go into .text section, 897 * therefore keeping it non-static as well; will also be used by JITs 898 * anyway later on, so do not let the compiler omit it. This also needs 899 * to go into kallsyms for correlation from e.g. bpftool, so naming 900 * must not change. 901 */ 902 noinline u64 __bpf_call_base(u64 r1, u64 r2, u64 r3, u64 r4, u64 r5) 903 { 904 return 0; 905 } 906 EXPORT_SYMBOL_GPL(__bpf_call_base); 907 908 /* All UAPI available opcodes. */ 909 #define BPF_INSN_MAP(INSN_2, INSN_3) \ 910 /* 32 bit ALU operations. */ \ 911 /* Register based. */ \ 912 INSN_3(ALU, ADD, X), \ 913 INSN_3(ALU, SUB, X), \ 914 INSN_3(ALU, AND, X), \ 915 INSN_3(ALU, OR, X), \ 916 INSN_3(ALU, LSH, X), \ 917 INSN_3(ALU, RSH, X), \ 918 INSN_3(ALU, XOR, X), \ 919 INSN_3(ALU, MUL, X), \ 920 INSN_3(ALU, MOV, X), \ 921 INSN_3(ALU, DIV, X), \ 922 INSN_3(ALU, MOD, X), \ 923 INSN_2(ALU, NEG), \ 924 INSN_3(ALU, END, TO_BE), \ 925 INSN_3(ALU, END, TO_LE), \ 926 /* Immediate based. */ \ 927 INSN_3(ALU, ADD, K), \ 928 INSN_3(ALU, SUB, K), \ 929 INSN_3(ALU, AND, K), \ 930 INSN_3(ALU, OR, K), \ 931 INSN_3(ALU, LSH, K), \ 932 INSN_3(ALU, RSH, K), \ 933 INSN_3(ALU, XOR, K), \ 934 INSN_3(ALU, MUL, K), \ 935 INSN_3(ALU, MOV, K), \ 936 INSN_3(ALU, DIV, K), \ 937 INSN_3(ALU, MOD, K), \ 938 /* 64 bit ALU operations. */ \ 939 /* Register based. */ \ 940 INSN_3(ALU64, ADD, X), \ 941 INSN_3(ALU64, SUB, X), \ 942 INSN_3(ALU64, AND, X), \ 943 INSN_3(ALU64, OR, X), \ 944 INSN_3(ALU64, LSH, X), \ 945 INSN_3(ALU64, RSH, X), \ 946 INSN_3(ALU64, XOR, X), \ 947 INSN_3(ALU64, MUL, X), \ 948 INSN_3(ALU64, MOV, X), \ 949 INSN_3(ALU64, ARSH, X), \ 950 INSN_3(ALU64, DIV, X), \ 951 INSN_3(ALU64, MOD, X), \ 952 INSN_2(ALU64, NEG), \ 953 /* Immediate based. */ \ 954 INSN_3(ALU64, ADD, K), \ 955 INSN_3(ALU64, SUB, K), \ 956 INSN_3(ALU64, AND, K), \ 957 INSN_3(ALU64, OR, K), \ 958 INSN_3(ALU64, LSH, K), \ 959 INSN_3(ALU64, RSH, K), \ 960 INSN_3(ALU64, XOR, K), \ 961 INSN_3(ALU64, MUL, K), \ 962 INSN_3(ALU64, MOV, K), \ 963 INSN_3(ALU64, ARSH, K), \ 964 INSN_3(ALU64, DIV, K), \ 965 INSN_3(ALU64, MOD, K), \ 966 /* Call instruction. */ \ 967 INSN_2(JMP, CALL), \ 968 /* Exit instruction. */ \ 969 INSN_2(JMP, EXIT), \ 970 /* Jump instructions. */ \ 971 /* Register based. */ \ 972 INSN_3(JMP, JEQ, X), \ 973 INSN_3(JMP, JNE, X), \ 974 INSN_3(JMP, JGT, X), \ 975 INSN_3(JMP, JLT, X), \ 976 INSN_3(JMP, JGE, X), \ 977 INSN_3(JMP, JLE, X), \ 978 INSN_3(JMP, JSGT, X), \ 979 INSN_3(JMP, JSLT, X), \ 980 INSN_3(JMP, JSGE, X), \ 981 INSN_3(JMP, JSLE, X), \ 982 INSN_3(JMP, JSET, X), \ 983 /* Immediate based. */ \ 984 INSN_3(JMP, JEQ, K), \ 985 INSN_3(JMP, JNE, K), \ 986 INSN_3(JMP, JGT, K), \ 987 INSN_3(JMP, JLT, K), \ 988 INSN_3(JMP, JGE, K), \ 989 INSN_3(JMP, JLE, K), \ 990 INSN_3(JMP, JSGT, K), \ 991 INSN_3(JMP, JSLT, K), \ 992 INSN_3(JMP, JSGE, K), \ 993 INSN_3(JMP, JSLE, K), \ 994 INSN_3(JMP, JSET, K), \ 995 INSN_2(JMP, JA), \ 996 /* Store instructions. */ \ 997 /* Register based. */ \ 998 INSN_3(STX, MEM, B), \ 999 INSN_3(STX, MEM, H), \ 1000 INSN_3(STX, MEM, W), \ 1001 INSN_3(STX, MEM, DW), \ 1002 INSN_3(STX, XADD, W), \ 1003 INSN_3(STX, XADD, DW), \ 1004 /* Immediate based. */ \ 1005 INSN_3(ST, MEM, B), \ 1006 INSN_3(ST, MEM, H), \ 1007 INSN_3(ST, MEM, W), \ 1008 INSN_3(ST, MEM, DW), \ 1009 /* Load instructions. */ \ 1010 /* Register based. */ \ 1011 INSN_3(LDX, MEM, B), \ 1012 INSN_3(LDX, MEM, H), \ 1013 INSN_3(LDX, MEM, W), \ 1014 INSN_3(LDX, MEM, DW), \ 1015 /* Immediate based. */ \ 1016 INSN_3(LD, IMM, DW) 1017 1018 bool bpf_opcode_in_insntable(u8 code) 1019 { 1020 #define BPF_INSN_2_TBL(x, y) [BPF_##x | BPF_##y] = true 1021 #define BPF_INSN_3_TBL(x, y, z) [BPF_##x | BPF_##y | BPF_##z] = true 1022 static const bool public_insntable[256] = { 1023 [0 ... 255] = false, 1024 /* Now overwrite non-defaults ... */ 1025 BPF_INSN_MAP(BPF_INSN_2_TBL, BPF_INSN_3_TBL), 1026 /* UAPI exposed, but rewritten opcodes. cBPF carry-over. */ 1027 [BPF_LD | BPF_ABS | BPF_B] = true, 1028 [BPF_LD | BPF_ABS | BPF_H] = true, 1029 [BPF_LD | BPF_ABS | BPF_W] = true, 1030 [BPF_LD | BPF_IND | BPF_B] = true, 1031 [BPF_LD | BPF_IND | BPF_H] = true, 1032 [BPF_LD | BPF_IND | BPF_W] = true, 1033 }; 1034 #undef BPF_INSN_3_TBL 1035 #undef BPF_INSN_2_TBL 1036 return public_insntable[code]; 1037 } 1038 1039 #ifndef CONFIG_BPF_JIT_ALWAYS_ON 1040 /** 1041 * __bpf_prog_run - run eBPF program on a given context 1042 * @ctx: is the data we are operating on 1043 * @insn: is the array of eBPF instructions 1044 * 1045 * Decode and execute eBPF instructions. 1046 */ 1047 static u64 ___bpf_prog_run(u64 *regs, const struct bpf_insn *insn, u64 *stack) 1048 { 1049 u64 tmp; 1050 #define BPF_INSN_2_LBL(x, y) [BPF_##x | BPF_##y] = &&x##_##y 1051 #define BPF_INSN_3_LBL(x, y, z) [BPF_##x | BPF_##y | BPF_##z] = &&x##_##y##_##z 1052 static const void *jumptable[256] = { 1053 [0 ... 255] = &&default_label, 1054 /* Now overwrite non-defaults ... */ 1055 BPF_INSN_MAP(BPF_INSN_2_LBL, BPF_INSN_3_LBL), 1056 /* Non-UAPI available opcodes. */ 1057 [BPF_JMP | BPF_CALL_ARGS] = &&JMP_CALL_ARGS, 1058 [BPF_JMP | BPF_TAIL_CALL] = &&JMP_TAIL_CALL, 1059 }; 1060 #undef BPF_INSN_3_LBL 1061 #undef BPF_INSN_2_LBL 1062 u32 tail_call_cnt = 0; 1063 1064 #define CONT ({ insn++; goto select_insn; }) 1065 #define CONT_JMP ({ insn++; goto select_insn; }) 1066 1067 select_insn: 1068 goto *jumptable[insn->code]; 1069 1070 /* ALU */ 1071 #define ALU(OPCODE, OP) \ 1072 ALU64_##OPCODE##_X: \ 1073 DST = DST OP SRC; \ 1074 CONT; \ 1075 ALU_##OPCODE##_X: \ 1076 DST = (u32) DST OP (u32) SRC; \ 1077 CONT; \ 1078 ALU64_##OPCODE##_K: \ 1079 DST = DST OP IMM; \ 1080 CONT; \ 1081 ALU_##OPCODE##_K: \ 1082 DST = (u32) DST OP (u32) IMM; \ 1083 CONT; 1084 1085 ALU(ADD, +) 1086 ALU(SUB, -) 1087 ALU(AND, &) 1088 ALU(OR, |) 1089 ALU(LSH, <<) 1090 ALU(RSH, >>) 1091 ALU(XOR, ^) 1092 ALU(MUL, *) 1093 #undef ALU 1094 ALU_NEG: 1095 DST = (u32) -DST; 1096 CONT; 1097 ALU64_NEG: 1098 DST = -DST; 1099 CONT; 1100 ALU_MOV_X: 1101 DST = (u32) SRC; 1102 CONT; 1103 ALU_MOV_K: 1104 DST = (u32) IMM; 1105 CONT; 1106 ALU64_MOV_X: 1107 DST = SRC; 1108 CONT; 1109 ALU64_MOV_K: 1110 DST = IMM; 1111 CONT; 1112 LD_IMM_DW: 1113 DST = (u64) (u32) insn[0].imm | ((u64) (u32) insn[1].imm) << 32; 1114 insn++; 1115 CONT; 1116 ALU64_ARSH_X: 1117 (*(s64 *) &DST) >>= SRC; 1118 CONT; 1119 ALU64_ARSH_K: 1120 (*(s64 *) &DST) >>= IMM; 1121 CONT; 1122 ALU64_MOD_X: 1123 div64_u64_rem(DST, SRC, &tmp); 1124 DST = tmp; 1125 CONT; 1126 ALU_MOD_X: 1127 tmp = (u32) DST; 1128 DST = do_div(tmp, (u32) SRC); 1129 CONT; 1130 ALU64_MOD_K: 1131 div64_u64_rem(DST, IMM, &tmp); 1132 DST = tmp; 1133 CONT; 1134 ALU_MOD_K: 1135 tmp = (u32) DST; 1136 DST = do_div(tmp, (u32) IMM); 1137 CONT; 1138 ALU64_DIV_X: 1139 DST = div64_u64(DST, SRC); 1140 CONT; 1141 ALU_DIV_X: 1142 tmp = (u32) DST; 1143 do_div(tmp, (u32) SRC); 1144 DST = (u32) tmp; 1145 CONT; 1146 ALU64_DIV_K: 1147 DST = div64_u64(DST, IMM); 1148 CONT; 1149 ALU_DIV_K: 1150 tmp = (u32) DST; 1151 do_div(tmp, (u32) IMM); 1152 DST = (u32) tmp; 1153 CONT; 1154 ALU_END_TO_BE: 1155 switch (IMM) { 1156 case 16: 1157 DST = (__force u16) cpu_to_be16(DST); 1158 break; 1159 case 32: 1160 DST = (__force u32) cpu_to_be32(DST); 1161 break; 1162 case 64: 1163 DST = (__force u64) cpu_to_be64(DST); 1164 break; 1165 } 1166 CONT; 1167 ALU_END_TO_LE: 1168 switch (IMM) { 1169 case 16: 1170 DST = (__force u16) cpu_to_le16(DST); 1171 break; 1172 case 32: 1173 DST = (__force u32) cpu_to_le32(DST); 1174 break; 1175 case 64: 1176 DST = (__force u64) cpu_to_le64(DST); 1177 break; 1178 } 1179 CONT; 1180 1181 /* CALL */ 1182 JMP_CALL: 1183 /* Function call scratches BPF_R1-BPF_R5 registers, 1184 * preserves BPF_R6-BPF_R9, and stores return value 1185 * into BPF_R0. 1186 */ 1187 BPF_R0 = (__bpf_call_base + insn->imm)(BPF_R1, BPF_R2, BPF_R3, 1188 BPF_R4, BPF_R5); 1189 CONT; 1190 1191 JMP_CALL_ARGS: 1192 BPF_R0 = (__bpf_call_base_args + insn->imm)(BPF_R1, BPF_R2, 1193 BPF_R3, BPF_R4, 1194 BPF_R5, 1195 insn + insn->off + 1); 1196 CONT; 1197 1198 JMP_TAIL_CALL: { 1199 struct bpf_map *map = (struct bpf_map *) (unsigned long) BPF_R2; 1200 struct bpf_array *array = container_of(map, struct bpf_array, map); 1201 struct bpf_prog *prog; 1202 u32 index = BPF_R3; 1203 1204 if (unlikely(index >= array->map.max_entries)) 1205 goto out; 1206 if (unlikely(tail_call_cnt > MAX_TAIL_CALL_CNT)) 1207 goto out; 1208 1209 tail_call_cnt++; 1210 1211 prog = READ_ONCE(array->ptrs[index]); 1212 if (!prog) 1213 goto out; 1214 1215 /* ARG1 at this point is guaranteed to point to CTX from 1216 * the verifier side due to the fact that the tail call is 1217 * handeled like a helper, that is, bpf_tail_call_proto, 1218 * where arg1_type is ARG_PTR_TO_CTX. 1219 */ 1220 insn = prog->insnsi; 1221 goto select_insn; 1222 out: 1223 CONT; 1224 } 1225 /* JMP */ 1226 JMP_JA: 1227 insn += insn->off; 1228 CONT; 1229 JMP_JEQ_X: 1230 if (DST == SRC) { 1231 insn += insn->off; 1232 CONT_JMP; 1233 } 1234 CONT; 1235 JMP_JEQ_K: 1236 if (DST == IMM) { 1237 insn += insn->off; 1238 CONT_JMP; 1239 } 1240 CONT; 1241 JMP_JNE_X: 1242 if (DST != SRC) { 1243 insn += insn->off; 1244 CONT_JMP; 1245 } 1246 CONT; 1247 JMP_JNE_K: 1248 if (DST != IMM) { 1249 insn += insn->off; 1250 CONT_JMP; 1251 } 1252 CONT; 1253 JMP_JGT_X: 1254 if (DST > SRC) { 1255 insn += insn->off; 1256 CONT_JMP; 1257 } 1258 CONT; 1259 JMP_JGT_K: 1260 if (DST > IMM) { 1261 insn += insn->off; 1262 CONT_JMP; 1263 } 1264 CONT; 1265 JMP_JLT_X: 1266 if (DST < SRC) { 1267 insn += insn->off; 1268 CONT_JMP; 1269 } 1270 CONT; 1271 JMP_JLT_K: 1272 if (DST < IMM) { 1273 insn += insn->off; 1274 CONT_JMP; 1275 } 1276 CONT; 1277 JMP_JGE_X: 1278 if (DST >= SRC) { 1279 insn += insn->off; 1280 CONT_JMP; 1281 } 1282 CONT; 1283 JMP_JGE_K: 1284 if (DST >= IMM) { 1285 insn += insn->off; 1286 CONT_JMP; 1287 } 1288 CONT; 1289 JMP_JLE_X: 1290 if (DST <= SRC) { 1291 insn += insn->off; 1292 CONT_JMP; 1293 } 1294 CONT; 1295 JMP_JLE_K: 1296 if (DST <= IMM) { 1297 insn += insn->off; 1298 CONT_JMP; 1299 } 1300 CONT; 1301 JMP_JSGT_X: 1302 if (((s64) DST) > ((s64) SRC)) { 1303 insn += insn->off; 1304 CONT_JMP; 1305 } 1306 CONT; 1307 JMP_JSGT_K: 1308 if (((s64) DST) > ((s64) IMM)) { 1309 insn += insn->off; 1310 CONT_JMP; 1311 } 1312 CONT; 1313 JMP_JSLT_X: 1314 if (((s64) DST) < ((s64) SRC)) { 1315 insn += insn->off; 1316 CONT_JMP; 1317 } 1318 CONT; 1319 JMP_JSLT_K: 1320 if (((s64) DST) < ((s64) IMM)) { 1321 insn += insn->off; 1322 CONT_JMP; 1323 } 1324 CONT; 1325 JMP_JSGE_X: 1326 if (((s64) DST) >= ((s64) SRC)) { 1327 insn += insn->off; 1328 CONT_JMP; 1329 } 1330 CONT; 1331 JMP_JSGE_K: 1332 if (((s64) DST) >= ((s64) IMM)) { 1333 insn += insn->off; 1334 CONT_JMP; 1335 } 1336 CONT; 1337 JMP_JSLE_X: 1338 if (((s64) DST) <= ((s64) SRC)) { 1339 insn += insn->off; 1340 CONT_JMP; 1341 } 1342 CONT; 1343 JMP_JSLE_K: 1344 if (((s64) DST) <= ((s64) IMM)) { 1345 insn += insn->off; 1346 CONT_JMP; 1347 } 1348 CONT; 1349 JMP_JSET_X: 1350 if (DST & SRC) { 1351 insn += insn->off; 1352 CONT_JMP; 1353 } 1354 CONT; 1355 JMP_JSET_K: 1356 if (DST & IMM) { 1357 insn += insn->off; 1358 CONT_JMP; 1359 } 1360 CONT; 1361 JMP_EXIT: 1362 return BPF_R0; 1363 1364 /* STX and ST and LDX*/ 1365 #define LDST(SIZEOP, SIZE) \ 1366 STX_MEM_##SIZEOP: \ 1367 *(SIZE *)(unsigned long) (DST + insn->off) = SRC; \ 1368 CONT; \ 1369 ST_MEM_##SIZEOP: \ 1370 *(SIZE *)(unsigned long) (DST + insn->off) = IMM; \ 1371 CONT; \ 1372 LDX_MEM_##SIZEOP: \ 1373 DST = *(SIZE *)(unsigned long) (SRC + insn->off); \ 1374 CONT; 1375 1376 LDST(B, u8) 1377 LDST(H, u16) 1378 LDST(W, u32) 1379 LDST(DW, u64) 1380 #undef LDST 1381 STX_XADD_W: /* lock xadd *(u32 *)(dst_reg + off16) += src_reg */ 1382 atomic_add((u32) SRC, (atomic_t *)(unsigned long) 1383 (DST + insn->off)); 1384 CONT; 1385 STX_XADD_DW: /* lock xadd *(u64 *)(dst_reg + off16) += src_reg */ 1386 atomic64_add((u64) SRC, (atomic64_t *)(unsigned long) 1387 (DST + insn->off)); 1388 CONT; 1389 1390 default_label: 1391 /* If we ever reach this, we have a bug somewhere. Die hard here 1392 * instead of just returning 0; we could be somewhere in a subprog, 1393 * so execution could continue otherwise which we do /not/ want. 1394 * 1395 * Note, verifier whitelists all opcodes in bpf_opcode_in_insntable(). 1396 */ 1397 pr_warn("BPF interpreter: unknown opcode %02x\n", insn->code); 1398 BUG_ON(1); 1399 return 0; 1400 } 1401 STACK_FRAME_NON_STANDARD(___bpf_prog_run); /* jump table */ 1402 1403 #define PROG_NAME(stack_size) __bpf_prog_run##stack_size 1404 #define DEFINE_BPF_PROG_RUN(stack_size) \ 1405 static unsigned int PROG_NAME(stack_size)(const void *ctx, const struct bpf_insn *insn) \ 1406 { \ 1407 u64 stack[stack_size / sizeof(u64)]; \ 1408 u64 regs[MAX_BPF_REG]; \ 1409 \ 1410 FP = (u64) (unsigned long) &stack[ARRAY_SIZE(stack)]; \ 1411 ARG1 = (u64) (unsigned long) ctx; \ 1412 return ___bpf_prog_run(regs, insn, stack); \ 1413 } 1414 1415 #define PROG_NAME_ARGS(stack_size) __bpf_prog_run_args##stack_size 1416 #define DEFINE_BPF_PROG_RUN_ARGS(stack_size) \ 1417 static u64 PROG_NAME_ARGS(stack_size)(u64 r1, u64 r2, u64 r3, u64 r4, u64 r5, \ 1418 const struct bpf_insn *insn) \ 1419 { \ 1420 u64 stack[stack_size / sizeof(u64)]; \ 1421 u64 regs[MAX_BPF_REG]; \ 1422 \ 1423 FP = (u64) (unsigned long) &stack[ARRAY_SIZE(stack)]; \ 1424 BPF_R1 = r1; \ 1425 BPF_R2 = r2; \ 1426 BPF_R3 = r3; \ 1427 BPF_R4 = r4; \ 1428 BPF_R5 = r5; \ 1429 return ___bpf_prog_run(regs, insn, stack); \ 1430 } 1431 1432 #define EVAL1(FN, X) FN(X) 1433 #define EVAL2(FN, X, Y...) FN(X) EVAL1(FN, Y) 1434 #define EVAL3(FN, X, Y...) FN(X) EVAL2(FN, Y) 1435 #define EVAL4(FN, X, Y...) FN(X) EVAL3(FN, Y) 1436 #define EVAL5(FN, X, Y...) FN(X) EVAL4(FN, Y) 1437 #define EVAL6(FN, X, Y...) FN(X) EVAL5(FN, Y) 1438 1439 EVAL6(DEFINE_BPF_PROG_RUN, 32, 64, 96, 128, 160, 192); 1440 EVAL6(DEFINE_BPF_PROG_RUN, 224, 256, 288, 320, 352, 384); 1441 EVAL4(DEFINE_BPF_PROG_RUN, 416, 448, 480, 512); 1442 1443 EVAL6(DEFINE_BPF_PROG_RUN_ARGS, 32, 64, 96, 128, 160, 192); 1444 EVAL6(DEFINE_BPF_PROG_RUN_ARGS, 224, 256, 288, 320, 352, 384); 1445 EVAL4(DEFINE_BPF_PROG_RUN_ARGS, 416, 448, 480, 512); 1446 1447 #define PROG_NAME_LIST(stack_size) PROG_NAME(stack_size), 1448 1449 static unsigned int (*interpreters[])(const void *ctx, 1450 const struct bpf_insn *insn) = { 1451 EVAL6(PROG_NAME_LIST, 32, 64, 96, 128, 160, 192) 1452 EVAL6(PROG_NAME_LIST, 224, 256, 288, 320, 352, 384) 1453 EVAL4(PROG_NAME_LIST, 416, 448, 480, 512) 1454 }; 1455 #undef PROG_NAME_LIST 1456 #define PROG_NAME_LIST(stack_size) PROG_NAME_ARGS(stack_size), 1457 static u64 (*interpreters_args[])(u64 r1, u64 r2, u64 r3, u64 r4, u64 r5, 1458 const struct bpf_insn *insn) = { 1459 EVAL6(PROG_NAME_LIST, 32, 64, 96, 128, 160, 192) 1460 EVAL6(PROG_NAME_LIST, 224, 256, 288, 320, 352, 384) 1461 EVAL4(PROG_NAME_LIST, 416, 448, 480, 512) 1462 }; 1463 #undef PROG_NAME_LIST 1464 1465 void bpf_patch_call_args(struct bpf_insn *insn, u32 stack_depth) 1466 { 1467 stack_depth = max_t(u32, stack_depth, 1); 1468 insn->off = (s16) insn->imm; 1469 insn->imm = interpreters_args[(round_up(stack_depth, 32) / 32) - 1] - 1470 __bpf_call_base_args; 1471 insn->code = BPF_JMP | BPF_CALL_ARGS; 1472 } 1473 1474 #else 1475 static unsigned int __bpf_prog_ret0_warn(const void *ctx, 1476 const struct bpf_insn *insn) 1477 { 1478 /* If this handler ever gets executed, then BPF_JIT_ALWAYS_ON 1479 * is not working properly, so warn about it! 1480 */ 1481 WARN_ON_ONCE(1); 1482 return 0; 1483 } 1484 #endif 1485 1486 bool bpf_prog_array_compatible(struct bpf_array *array, 1487 const struct bpf_prog *fp) 1488 { 1489 if (fp->kprobe_override) 1490 return false; 1491 1492 if (!array->owner_prog_type) { 1493 /* There's no owner yet where we could check for 1494 * compatibility. 1495 */ 1496 array->owner_prog_type = fp->type; 1497 array->owner_jited = fp->jited; 1498 1499 return true; 1500 } 1501 1502 return array->owner_prog_type == fp->type && 1503 array->owner_jited == fp->jited; 1504 } 1505 1506 static int bpf_check_tail_call(const struct bpf_prog *fp) 1507 { 1508 struct bpf_prog_aux *aux = fp->aux; 1509 int i; 1510 1511 for (i = 0; i < aux->used_map_cnt; i++) { 1512 struct bpf_map *map = aux->used_maps[i]; 1513 struct bpf_array *array; 1514 1515 if (map->map_type != BPF_MAP_TYPE_PROG_ARRAY) 1516 continue; 1517 1518 array = container_of(map, struct bpf_array, map); 1519 if (!bpf_prog_array_compatible(array, fp)) 1520 return -EINVAL; 1521 } 1522 1523 return 0; 1524 } 1525 1526 static void bpf_prog_select_func(struct bpf_prog *fp) 1527 { 1528 #ifndef CONFIG_BPF_JIT_ALWAYS_ON 1529 u32 stack_depth = max_t(u32, fp->aux->stack_depth, 1); 1530 1531 fp->bpf_func = interpreters[(round_up(stack_depth, 32) / 32) - 1]; 1532 #else 1533 fp->bpf_func = __bpf_prog_ret0_warn; 1534 #endif 1535 } 1536 1537 /** 1538 * bpf_prog_select_runtime - select exec runtime for BPF program 1539 * @fp: bpf_prog populated with internal BPF program 1540 * @err: pointer to error variable 1541 * 1542 * Try to JIT eBPF program, if JIT is not available, use interpreter. 1543 * The BPF program will be executed via BPF_PROG_RUN() macro. 1544 */ 1545 struct bpf_prog *bpf_prog_select_runtime(struct bpf_prog *fp, int *err) 1546 { 1547 /* In case of BPF to BPF calls, verifier did all the prep 1548 * work with regards to JITing, etc. 1549 */ 1550 if (fp->bpf_func) 1551 goto finalize; 1552 1553 bpf_prog_select_func(fp); 1554 1555 /* eBPF JITs can rewrite the program in case constant 1556 * blinding is active. However, in case of error during 1557 * blinding, bpf_int_jit_compile() must always return a 1558 * valid program, which in this case would simply not 1559 * be JITed, but falls back to the interpreter. 1560 */ 1561 if (!bpf_prog_is_dev_bound(fp->aux)) { 1562 fp = bpf_int_jit_compile(fp); 1563 #ifdef CONFIG_BPF_JIT_ALWAYS_ON 1564 if (!fp->jited) { 1565 *err = -ENOTSUPP; 1566 return fp; 1567 } 1568 #endif 1569 } else { 1570 *err = bpf_prog_offload_compile(fp); 1571 if (*err) 1572 return fp; 1573 } 1574 1575 finalize: 1576 bpf_prog_lock_ro(fp); 1577 1578 /* The tail call compatibility check can only be done at 1579 * this late stage as we need to determine, if we deal 1580 * with JITed or non JITed program concatenations and not 1581 * all eBPF JITs might immediately support all features. 1582 */ 1583 *err = bpf_check_tail_call(fp); 1584 1585 return fp; 1586 } 1587 EXPORT_SYMBOL_GPL(bpf_prog_select_runtime); 1588 1589 static unsigned int __bpf_prog_ret1(const void *ctx, 1590 const struct bpf_insn *insn) 1591 { 1592 return 1; 1593 } 1594 1595 static struct bpf_prog_dummy { 1596 struct bpf_prog prog; 1597 } dummy_bpf_prog = { 1598 .prog = { 1599 .bpf_func = __bpf_prog_ret1, 1600 }, 1601 }; 1602 1603 /* to avoid allocating empty bpf_prog_array for cgroups that 1604 * don't have bpf program attached use one global 'empty_prog_array' 1605 * It will not be modified the caller of bpf_prog_array_alloc() 1606 * (since caller requested prog_cnt == 0) 1607 * that pointer should be 'freed' by bpf_prog_array_free() 1608 */ 1609 static struct { 1610 struct bpf_prog_array hdr; 1611 struct bpf_prog *null_prog; 1612 } empty_prog_array = { 1613 .null_prog = NULL, 1614 }; 1615 1616 struct bpf_prog_array *bpf_prog_array_alloc(u32 prog_cnt, gfp_t flags) 1617 { 1618 if (prog_cnt) 1619 return kzalloc(sizeof(struct bpf_prog_array) + 1620 sizeof(struct bpf_prog_array_item) * 1621 (prog_cnt + 1), 1622 flags); 1623 1624 return &empty_prog_array.hdr; 1625 } 1626 1627 void bpf_prog_array_free(struct bpf_prog_array __rcu *progs) 1628 { 1629 if (!progs || 1630 progs == (struct bpf_prog_array __rcu *)&empty_prog_array.hdr) 1631 return; 1632 kfree_rcu(progs, rcu); 1633 } 1634 1635 int bpf_prog_array_length(struct bpf_prog_array __rcu *array) 1636 { 1637 struct bpf_prog_array_item *item; 1638 u32 cnt = 0; 1639 1640 rcu_read_lock(); 1641 item = rcu_dereference(array)->items; 1642 for (; item->prog; item++) 1643 if (item->prog != &dummy_bpf_prog.prog) 1644 cnt++; 1645 rcu_read_unlock(); 1646 return cnt; 1647 } 1648 1649 1650 static bool bpf_prog_array_copy_core(struct bpf_prog_array __rcu *array, 1651 u32 *prog_ids, 1652 u32 request_cnt) 1653 { 1654 struct bpf_prog_array_item *item; 1655 int i = 0; 1656 1657 item = rcu_dereference_check(array, 1)->items; 1658 for (; item->prog; item++) { 1659 if (item->prog == &dummy_bpf_prog.prog) 1660 continue; 1661 prog_ids[i] = item->prog->aux->id; 1662 if (++i == request_cnt) { 1663 item++; 1664 break; 1665 } 1666 } 1667 1668 return !!(item->prog); 1669 } 1670 1671 int bpf_prog_array_copy_to_user(struct bpf_prog_array __rcu *array, 1672 __u32 __user *prog_ids, u32 cnt) 1673 { 1674 unsigned long err = 0; 1675 bool nospc; 1676 u32 *ids; 1677 1678 /* users of this function are doing: 1679 * cnt = bpf_prog_array_length(); 1680 * if (cnt > 0) 1681 * bpf_prog_array_copy_to_user(..., cnt); 1682 * so below kcalloc doesn't need extra cnt > 0 check, but 1683 * bpf_prog_array_length() releases rcu lock and 1684 * prog array could have been swapped with empty or larger array, 1685 * so always copy 'cnt' prog_ids to the user. 1686 * In a rare race the user will see zero prog_ids 1687 */ 1688 ids = kcalloc(cnt, sizeof(u32), GFP_USER | __GFP_NOWARN); 1689 if (!ids) 1690 return -ENOMEM; 1691 rcu_read_lock(); 1692 nospc = bpf_prog_array_copy_core(array, ids, cnt); 1693 rcu_read_unlock(); 1694 err = copy_to_user(prog_ids, ids, cnt * sizeof(u32)); 1695 kfree(ids); 1696 if (err) 1697 return -EFAULT; 1698 if (nospc) 1699 return -ENOSPC; 1700 return 0; 1701 } 1702 1703 void bpf_prog_array_delete_safe(struct bpf_prog_array __rcu *array, 1704 struct bpf_prog *old_prog) 1705 { 1706 struct bpf_prog_array_item *item = array->items; 1707 1708 for (; item->prog; item++) 1709 if (item->prog == old_prog) { 1710 WRITE_ONCE(item->prog, &dummy_bpf_prog.prog); 1711 break; 1712 } 1713 } 1714 1715 int bpf_prog_array_copy(struct bpf_prog_array __rcu *old_array, 1716 struct bpf_prog *exclude_prog, 1717 struct bpf_prog *include_prog, 1718 struct bpf_prog_array **new_array) 1719 { 1720 int new_prog_cnt, carry_prog_cnt = 0; 1721 struct bpf_prog_array_item *existing; 1722 struct bpf_prog_array *array; 1723 bool found_exclude = false; 1724 int new_prog_idx = 0; 1725 1726 /* Figure out how many existing progs we need to carry over to 1727 * the new array. 1728 */ 1729 if (old_array) { 1730 existing = old_array->items; 1731 for (; existing->prog; existing++) { 1732 if (existing->prog == exclude_prog) { 1733 found_exclude = true; 1734 continue; 1735 } 1736 if (existing->prog != &dummy_bpf_prog.prog) 1737 carry_prog_cnt++; 1738 if (existing->prog == include_prog) 1739 return -EEXIST; 1740 } 1741 } 1742 1743 if (exclude_prog && !found_exclude) 1744 return -ENOENT; 1745 1746 /* How many progs (not NULL) will be in the new array? */ 1747 new_prog_cnt = carry_prog_cnt; 1748 if (include_prog) 1749 new_prog_cnt += 1; 1750 1751 /* Do we have any prog (not NULL) in the new array? */ 1752 if (!new_prog_cnt) { 1753 *new_array = NULL; 1754 return 0; 1755 } 1756 1757 /* +1 as the end of prog_array is marked with NULL */ 1758 array = bpf_prog_array_alloc(new_prog_cnt + 1, GFP_KERNEL); 1759 if (!array) 1760 return -ENOMEM; 1761 1762 /* Fill in the new prog array */ 1763 if (carry_prog_cnt) { 1764 existing = old_array->items; 1765 for (; existing->prog; existing++) 1766 if (existing->prog != exclude_prog && 1767 existing->prog != &dummy_bpf_prog.prog) { 1768 array->items[new_prog_idx++].prog = 1769 existing->prog; 1770 } 1771 } 1772 if (include_prog) 1773 array->items[new_prog_idx++].prog = include_prog; 1774 array->items[new_prog_idx].prog = NULL; 1775 *new_array = array; 1776 return 0; 1777 } 1778 1779 int bpf_prog_array_copy_info(struct bpf_prog_array __rcu *array, 1780 u32 *prog_ids, u32 request_cnt, 1781 u32 *prog_cnt) 1782 { 1783 u32 cnt = 0; 1784 1785 if (array) 1786 cnt = bpf_prog_array_length(array); 1787 1788 *prog_cnt = cnt; 1789 1790 /* return early if user requested only program count or nothing to copy */ 1791 if (!request_cnt || !cnt) 1792 return 0; 1793 1794 /* this function is called under trace/bpf_trace.c: bpf_event_mutex */ 1795 return bpf_prog_array_copy_core(array, prog_ids, request_cnt) ? -ENOSPC 1796 : 0; 1797 } 1798 1799 static void bpf_prog_free_deferred(struct work_struct *work) 1800 { 1801 struct bpf_prog_aux *aux; 1802 int i; 1803 1804 aux = container_of(work, struct bpf_prog_aux, work); 1805 if (bpf_prog_is_dev_bound(aux)) 1806 bpf_prog_offload_destroy(aux->prog); 1807 #ifdef CONFIG_PERF_EVENTS 1808 if (aux->prog->has_callchain_buf) 1809 put_callchain_buffers(); 1810 #endif 1811 for (i = 0; i < aux->func_cnt; i++) 1812 bpf_jit_free(aux->func[i]); 1813 if (aux->func_cnt) { 1814 kfree(aux->func); 1815 bpf_prog_unlock_free(aux->prog); 1816 } else { 1817 bpf_jit_free(aux->prog); 1818 } 1819 } 1820 1821 /* Free internal BPF program */ 1822 void bpf_prog_free(struct bpf_prog *fp) 1823 { 1824 struct bpf_prog_aux *aux = fp->aux; 1825 1826 INIT_WORK(&aux->work, bpf_prog_free_deferred); 1827 schedule_work(&aux->work); 1828 } 1829 EXPORT_SYMBOL_GPL(bpf_prog_free); 1830 1831 /* RNG for unpriviledged user space with separated state from prandom_u32(). */ 1832 static DEFINE_PER_CPU(struct rnd_state, bpf_user_rnd_state); 1833 1834 void bpf_user_rnd_init_once(void) 1835 { 1836 prandom_init_once(&bpf_user_rnd_state); 1837 } 1838 1839 BPF_CALL_0(bpf_user_rnd_u32) 1840 { 1841 /* Should someone ever have the rather unwise idea to use some 1842 * of the registers passed into this function, then note that 1843 * this function is called from native eBPF and classic-to-eBPF 1844 * transformations. Register assignments from both sides are 1845 * different, f.e. classic always sets fn(ctx, A, X) here. 1846 */ 1847 struct rnd_state *state; 1848 u32 res; 1849 1850 state = &get_cpu_var(bpf_user_rnd_state); 1851 res = prandom_u32_state(state); 1852 put_cpu_var(bpf_user_rnd_state); 1853 1854 return res; 1855 } 1856 1857 /* Weak definitions of helper functions in case we don't have bpf syscall. */ 1858 const struct bpf_func_proto bpf_map_lookup_elem_proto __weak; 1859 const struct bpf_func_proto bpf_map_update_elem_proto __weak; 1860 const struct bpf_func_proto bpf_map_delete_elem_proto __weak; 1861 const struct bpf_func_proto bpf_map_push_elem_proto __weak; 1862 const struct bpf_func_proto bpf_map_pop_elem_proto __weak; 1863 const struct bpf_func_proto bpf_map_peek_elem_proto __weak; 1864 1865 const struct bpf_func_proto bpf_get_prandom_u32_proto __weak; 1866 const struct bpf_func_proto bpf_get_smp_processor_id_proto __weak; 1867 const struct bpf_func_proto bpf_get_numa_node_id_proto __weak; 1868 const struct bpf_func_proto bpf_ktime_get_ns_proto __weak; 1869 1870 const struct bpf_func_proto bpf_get_current_pid_tgid_proto __weak; 1871 const struct bpf_func_proto bpf_get_current_uid_gid_proto __weak; 1872 const struct bpf_func_proto bpf_get_current_comm_proto __weak; 1873 const struct bpf_func_proto bpf_get_current_cgroup_id_proto __weak; 1874 const struct bpf_func_proto bpf_get_local_storage_proto __weak; 1875 1876 const struct bpf_func_proto * __weak bpf_get_trace_printk_proto(void) 1877 { 1878 return NULL; 1879 } 1880 1881 u64 __weak 1882 bpf_event_output(struct bpf_map *map, u64 flags, void *meta, u64 meta_size, 1883 void *ctx, u64 ctx_size, bpf_ctx_copy_t ctx_copy) 1884 { 1885 return -ENOTSUPP; 1886 } 1887 EXPORT_SYMBOL_GPL(bpf_event_output); 1888 1889 /* Always built-in helper functions. */ 1890 const struct bpf_func_proto bpf_tail_call_proto = { 1891 .func = NULL, 1892 .gpl_only = false, 1893 .ret_type = RET_VOID, 1894 .arg1_type = ARG_PTR_TO_CTX, 1895 .arg2_type = ARG_CONST_MAP_PTR, 1896 .arg3_type = ARG_ANYTHING, 1897 }; 1898 1899 /* Stub for JITs that only support cBPF. eBPF programs are interpreted. 1900 * It is encouraged to implement bpf_int_jit_compile() instead, so that 1901 * eBPF and implicitly also cBPF can get JITed! 1902 */ 1903 struct bpf_prog * __weak bpf_int_jit_compile(struct bpf_prog *prog) 1904 { 1905 return prog; 1906 } 1907 1908 /* Stub for JITs that support eBPF. All cBPF code gets transformed into 1909 * eBPF by the kernel and is later compiled by bpf_int_jit_compile(). 1910 */ 1911 void __weak bpf_jit_compile(struct bpf_prog *prog) 1912 { 1913 } 1914 1915 bool __weak bpf_helper_changes_pkt_data(void *func) 1916 { 1917 return false; 1918 } 1919 1920 /* To execute LD_ABS/LD_IND instructions __bpf_prog_run() may call 1921 * skb_copy_bits(), so provide a weak definition of it for NET-less config. 1922 */ 1923 int __weak skb_copy_bits(const struct sk_buff *skb, int offset, void *to, 1924 int len) 1925 { 1926 return -EFAULT; 1927 } 1928 1929 /* All definitions of tracepoints related to BPF. */ 1930 #define CREATE_TRACE_POINTS 1931 #include <linux/bpf_trace.h> 1932 1933 EXPORT_TRACEPOINT_SYMBOL_GPL(xdp_exception); 1934