1 // SPDX-License-Identifier: GPL-2.0-or-later 2 /* 3 * Linux Socket Filter - Kernel level socket filtering 4 * 5 * Based on the design of the Berkeley Packet Filter. The new 6 * internal format has been designed by PLUMgrid: 7 * 8 * Copyright (c) 2011 - 2014 PLUMgrid, http://plumgrid.com 9 * 10 * Authors: 11 * 12 * Jay Schulist <jschlst@samba.org> 13 * Alexei Starovoitov <ast@plumgrid.com> 14 * Daniel Borkmann <dborkman@redhat.com> 15 * 16 * Andi Kleen - Fix a few bad bugs and races. 17 * Kris Katterjohn - Added many additional checks in bpf_check_classic() 18 */ 19 20 #include <uapi/linux/btf.h> 21 #include <linux/filter.h> 22 #include <linux/skbuff.h> 23 #include <linux/vmalloc.h> 24 #include <linux/random.h> 25 #include <linux/moduleloader.h> 26 #include <linux/bpf.h> 27 #include <linux/btf.h> 28 #include <linux/frame.h> 29 #include <linux/rbtree_latch.h> 30 #include <linux/kallsyms.h> 31 #include <linux/rcupdate.h> 32 #include <linux/perf_event.h> 33 #include <linux/extable.h> 34 #include <linux/log2.h> 35 #include <asm/unaligned.h> 36 37 /* Registers */ 38 #define BPF_R0 regs[BPF_REG_0] 39 #define BPF_R1 regs[BPF_REG_1] 40 #define BPF_R2 regs[BPF_REG_2] 41 #define BPF_R3 regs[BPF_REG_3] 42 #define BPF_R4 regs[BPF_REG_4] 43 #define BPF_R5 regs[BPF_REG_5] 44 #define BPF_R6 regs[BPF_REG_6] 45 #define BPF_R7 regs[BPF_REG_7] 46 #define BPF_R8 regs[BPF_REG_8] 47 #define BPF_R9 regs[BPF_REG_9] 48 #define BPF_R10 regs[BPF_REG_10] 49 50 /* Named registers */ 51 #define DST regs[insn->dst_reg] 52 #define SRC regs[insn->src_reg] 53 #define FP regs[BPF_REG_FP] 54 #define AX regs[BPF_REG_AX] 55 #define ARG1 regs[BPF_REG_ARG1] 56 #define CTX regs[BPF_REG_CTX] 57 #define IMM insn->imm 58 59 /* No hurry in this branch 60 * 61 * Exported for the bpf jit load helper. 62 */ 63 void *bpf_internal_load_pointer_neg_helper(const struct sk_buff *skb, int k, unsigned int size) 64 { 65 u8 *ptr = NULL; 66 67 if (k >= SKF_NET_OFF) 68 ptr = skb_network_header(skb) + k - SKF_NET_OFF; 69 else if (k >= SKF_LL_OFF) 70 ptr = skb_mac_header(skb) + k - SKF_LL_OFF; 71 72 if (ptr >= skb->head && ptr + size <= skb_tail_pointer(skb)) 73 return ptr; 74 75 return NULL; 76 } 77 78 struct bpf_prog *bpf_prog_alloc_no_stats(unsigned int size, gfp_t gfp_extra_flags) 79 { 80 gfp_t gfp_flags = GFP_KERNEL | __GFP_ZERO | gfp_extra_flags; 81 struct bpf_prog_aux *aux; 82 struct bpf_prog *fp; 83 84 size = round_up(size, PAGE_SIZE); 85 fp = __vmalloc(size, gfp_flags); 86 if (fp == NULL) 87 return NULL; 88 89 aux = kzalloc(sizeof(*aux), GFP_KERNEL | gfp_extra_flags); 90 if (aux == NULL) { 91 vfree(fp); 92 return NULL; 93 } 94 95 fp->pages = size / PAGE_SIZE; 96 fp->aux = aux; 97 fp->aux->prog = fp; 98 fp->jit_requested = ebpf_jit_enabled(); 99 100 INIT_LIST_HEAD_RCU(&fp->aux->ksym.lnode); 101 102 return fp; 103 } 104 105 struct bpf_prog *bpf_prog_alloc(unsigned int size, gfp_t gfp_extra_flags) 106 { 107 gfp_t gfp_flags = GFP_KERNEL | __GFP_ZERO | gfp_extra_flags; 108 struct bpf_prog *prog; 109 int cpu; 110 111 prog = bpf_prog_alloc_no_stats(size, gfp_extra_flags); 112 if (!prog) 113 return NULL; 114 115 prog->aux->stats = alloc_percpu_gfp(struct bpf_prog_stats, gfp_flags); 116 if (!prog->aux->stats) { 117 kfree(prog->aux); 118 vfree(prog); 119 return NULL; 120 } 121 122 for_each_possible_cpu(cpu) { 123 struct bpf_prog_stats *pstats; 124 125 pstats = per_cpu_ptr(prog->aux->stats, cpu); 126 u64_stats_init(&pstats->syncp); 127 } 128 return prog; 129 } 130 EXPORT_SYMBOL_GPL(bpf_prog_alloc); 131 132 int bpf_prog_alloc_jited_linfo(struct bpf_prog *prog) 133 { 134 if (!prog->aux->nr_linfo || !prog->jit_requested) 135 return 0; 136 137 prog->aux->jited_linfo = kcalloc(prog->aux->nr_linfo, 138 sizeof(*prog->aux->jited_linfo), 139 GFP_KERNEL | __GFP_NOWARN); 140 if (!prog->aux->jited_linfo) 141 return -ENOMEM; 142 143 return 0; 144 } 145 146 void bpf_prog_free_jited_linfo(struct bpf_prog *prog) 147 { 148 kfree(prog->aux->jited_linfo); 149 prog->aux->jited_linfo = NULL; 150 } 151 152 void bpf_prog_free_unused_jited_linfo(struct bpf_prog *prog) 153 { 154 if (prog->aux->jited_linfo && !prog->aux->jited_linfo[0]) 155 bpf_prog_free_jited_linfo(prog); 156 } 157 158 /* The jit engine is responsible to provide an array 159 * for insn_off to the jited_off mapping (insn_to_jit_off). 160 * 161 * The idx to this array is the insn_off. Hence, the insn_off 162 * here is relative to the prog itself instead of the main prog. 163 * This array has one entry for each xlated bpf insn. 164 * 165 * jited_off is the byte off to the last byte of the jited insn. 166 * 167 * Hence, with 168 * insn_start: 169 * The first bpf insn off of the prog. The insn off 170 * here is relative to the main prog. 171 * e.g. if prog is a subprog, insn_start > 0 172 * linfo_idx: 173 * The prog's idx to prog->aux->linfo and jited_linfo 174 * 175 * jited_linfo[linfo_idx] = prog->bpf_func 176 * 177 * For i > linfo_idx, 178 * 179 * jited_linfo[i] = prog->bpf_func + 180 * insn_to_jit_off[linfo[i].insn_off - insn_start - 1] 181 */ 182 void bpf_prog_fill_jited_linfo(struct bpf_prog *prog, 183 const u32 *insn_to_jit_off) 184 { 185 u32 linfo_idx, insn_start, insn_end, nr_linfo, i; 186 const struct bpf_line_info *linfo; 187 void **jited_linfo; 188 189 if (!prog->aux->jited_linfo) 190 /* Userspace did not provide linfo */ 191 return; 192 193 linfo_idx = prog->aux->linfo_idx; 194 linfo = &prog->aux->linfo[linfo_idx]; 195 insn_start = linfo[0].insn_off; 196 insn_end = insn_start + prog->len; 197 198 jited_linfo = &prog->aux->jited_linfo[linfo_idx]; 199 jited_linfo[0] = prog->bpf_func; 200 201 nr_linfo = prog->aux->nr_linfo - linfo_idx; 202 203 for (i = 1; i < nr_linfo && linfo[i].insn_off < insn_end; i++) 204 /* The verifier ensures that linfo[i].insn_off is 205 * strictly increasing 206 */ 207 jited_linfo[i] = prog->bpf_func + 208 insn_to_jit_off[linfo[i].insn_off - insn_start - 1]; 209 } 210 211 void bpf_prog_free_linfo(struct bpf_prog *prog) 212 { 213 bpf_prog_free_jited_linfo(prog); 214 kvfree(prog->aux->linfo); 215 } 216 217 struct bpf_prog *bpf_prog_realloc(struct bpf_prog *fp_old, unsigned int size, 218 gfp_t gfp_extra_flags) 219 { 220 gfp_t gfp_flags = GFP_KERNEL | __GFP_ZERO | gfp_extra_flags; 221 struct bpf_prog *fp; 222 u32 pages, delta; 223 int ret; 224 225 size = round_up(size, PAGE_SIZE); 226 pages = size / PAGE_SIZE; 227 if (pages <= fp_old->pages) 228 return fp_old; 229 230 delta = pages - fp_old->pages; 231 ret = __bpf_prog_charge(fp_old->aux->user, delta); 232 if (ret) 233 return NULL; 234 235 fp = __vmalloc(size, gfp_flags); 236 if (fp == NULL) { 237 __bpf_prog_uncharge(fp_old->aux->user, delta); 238 } else { 239 memcpy(fp, fp_old, fp_old->pages * PAGE_SIZE); 240 fp->pages = pages; 241 fp->aux->prog = fp; 242 243 /* We keep fp->aux from fp_old around in the new 244 * reallocated structure. 245 */ 246 fp_old->aux = NULL; 247 __bpf_prog_free(fp_old); 248 } 249 250 return fp; 251 } 252 253 void __bpf_prog_free(struct bpf_prog *fp) 254 { 255 if (fp->aux) { 256 free_percpu(fp->aux->stats); 257 kfree(fp->aux->poke_tab); 258 kfree(fp->aux); 259 } 260 vfree(fp); 261 } 262 263 int bpf_prog_calc_tag(struct bpf_prog *fp) 264 { 265 const u32 bits_offset = SHA1_BLOCK_SIZE - sizeof(__be64); 266 u32 raw_size = bpf_prog_tag_scratch_size(fp); 267 u32 digest[SHA1_DIGEST_WORDS]; 268 u32 ws[SHA1_WORKSPACE_WORDS]; 269 u32 i, bsize, psize, blocks; 270 struct bpf_insn *dst; 271 bool was_ld_map; 272 u8 *raw, *todo; 273 __be32 *result; 274 __be64 *bits; 275 276 raw = vmalloc(raw_size); 277 if (!raw) 278 return -ENOMEM; 279 280 sha1_init(digest); 281 memset(ws, 0, sizeof(ws)); 282 283 /* We need to take out the map fd for the digest calculation 284 * since they are unstable from user space side. 285 */ 286 dst = (void *)raw; 287 for (i = 0, was_ld_map = false; i < fp->len; i++) { 288 dst[i] = fp->insnsi[i]; 289 if (!was_ld_map && 290 dst[i].code == (BPF_LD | BPF_IMM | BPF_DW) && 291 (dst[i].src_reg == BPF_PSEUDO_MAP_FD || 292 dst[i].src_reg == BPF_PSEUDO_MAP_VALUE)) { 293 was_ld_map = true; 294 dst[i].imm = 0; 295 } else if (was_ld_map && 296 dst[i].code == 0 && 297 dst[i].dst_reg == 0 && 298 dst[i].src_reg == 0 && 299 dst[i].off == 0) { 300 was_ld_map = false; 301 dst[i].imm = 0; 302 } else { 303 was_ld_map = false; 304 } 305 } 306 307 psize = bpf_prog_insn_size(fp); 308 memset(&raw[psize], 0, raw_size - psize); 309 raw[psize++] = 0x80; 310 311 bsize = round_up(psize, SHA1_BLOCK_SIZE); 312 blocks = bsize / SHA1_BLOCK_SIZE; 313 todo = raw; 314 if (bsize - psize >= sizeof(__be64)) { 315 bits = (__be64 *)(todo + bsize - sizeof(__be64)); 316 } else { 317 bits = (__be64 *)(todo + bsize + bits_offset); 318 blocks++; 319 } 320 *bits = cpu_to_be64((psize - 1) << 3); 321 322 while (blocks--) { 323 sha1_transform(digest, todo, ws); 324 todo += SHA1_BLOCK_SIZE; 325 } 326 327 result = (__force __be32 *)digest; 328 for (i = 0; i < SHA1_DIGEST_WORDS; i++) 329 result[i] = cpu_to_be32(digest[i]); 330 memcpy(fp->tag, result, sizeof(fp->tag)); 331 332 vfree(raw); 333 return 0; 334 } 335 336 static int bpf_adj_delta_to_imm(struct bpf_insn *insn, u32 pos, s32 end_old, 337 s32 end_new, s32 curr, const bool probe_pass) 338 { 339 const s64 imm_min = S32_MIN, imm_max = S32_MAX; 340 s32 delta = end_new - end_old; 341 s64 imm = insn->imm; 342 343 if (curr < pos && curr + imm + 1 >= end_old) 344 imm += delta; 345 else if (curr >= end_new && curr + imm + 1 < end_new) 346 imm -= delta; 347 if (imm < imm_min || imm > imm_max) 348 return -ERANGE; 349 if (!probe_pass) 350 insn->imm = imm; 351 return 0; 352 } 353 354 static int bpf_adj_delta_to_off(struct bpf_insn *insn, u32 pos, s32 end_old, 355 s32 end_new, s32 curr, const bool probe_pass) 356 { 357 const s32 off_min = S16_MIN, off_max = S16_MAX; 358 s32 delta = end_new - end_old; 359 s32 off = insn->off; 360 361 if (curr < pos && curr + off + 1 >= end_old) 362 off += delta; 363 else if (curr >= end_new && curr + off + 1 < end_new) 364 off -= delta; 365 if (off < off_min || off > off_max) 366 return -ERANGE; 367 if (!probe_pass) 368 insn->off = off; 369 return 0; 370 } 371 372 static int bpf_adj_branches(struct bpf_prog *prog, u32 pos, s32 end_old, 373 s32 end_new, const bool probe_pass) 374 { 375 u32 i, insn_cnt = prog->len + (probe_pass ? end_new - end_old : 0); 376 struct bpf_insn *insn = prog->insnsi; 377 int ret = 0; 378 379 for (i = 0; i < insn_cnt; i++, insn++) { 380 u8 code; 381 382 /* In the probing pass we still operate on the original, 383 * unpatched image in order to check overflows before we 384 * do any other adjustments. Therefore skip the patchlet. 385 */ 386 if (probe_pass && i == pos) { 387 i = end_new; 388 insn = prog->insnsi + end_old; 389 } 390 code = insn->code; 391 if ((BPF_CLASS(code) != BPF_JMP && 392 BPF_CLASS(code) != BPF_JMP32) || 393 BPF_OP(code) == BPF_EXIT) 394 continue; 395 /* Adjust offset of jmps if we cross patch boundaries. */ 396 if (BPF_OP(code) == BPF_CALL) { 397 if (insn->src_reg != BPF_PSEUDO_CALL) 398 continue; 399 ret = bpf_adj_delta_to_imm(insn, pos, end_old, 400 end_new, i, probe_pass); 401 } else { 402 ret = bpf_adj_delta_to_off(insn, pos, end_old, 403 end_new, i, probe_pass); 404 } 405 if (ret) 406 break; 407 } 408 409 return ret; 410 } 411 412 static void bpf_adj_linfo(struct bpf_prog *prog, u32 off, u32 delta) 413 { 414 struct bpf_line_info *linfo; 415 u32 i, nr_linfo; 416 417 nr_linfo = prog->aux->nr_linfo; 418 if (!nr_linfo || !delta) 419 return; 420 421 linfo = prog->aux->linfo; 422 423 for (i = 0; i < nr_linfo; i++) 424 if (off < linfo[i].insn_off) 425 break; 426 427 /* Push all off < linfo[i].insn_off by delta */ 428 for (; i < nr_linfo; i++) 429 linfo[i].insn_off += delta; 430 } 431 432 struct bpf_prog *bpf_patch_insn_single(struct bpf_prog *prog, u32 off, 433 const struct bpf_insn *patch, u32 len) 434 { 435 u32 insn_adj_cnt, insn_rest, insn_delta = len - 1; 436 const u32 cnt_max = S16_MAX; 437 struct bpf_prog *prog_adj; 438 int err; 439 440 /* Since our patchlet doesn't expand the image, we're done. */ 441 if (insn_delta == 0) { 442 memcpy(prog->insnsi + off, patch, sizeof(*patch)); 443 return prog; 444 } 445 446 insn_adj_cnt = prog->len + insn_delta; 447 448 /* Reject anything that would potentially let the insn->off 449 * target overflow when we have excessive program expansions. 450 * We need to probe here before we do any reallocation where 451 * we afterwards may not fail anymore. 452 */ 453 if (insn_adj_cnt > cnt_max && 454 (err = bpf_adj_branches(prog, off, off + 1, off + len, true))) 455 return ERR_PTR(err); 456 457 /* Several new instructions need to be inserted. Make room 458 * for them. Likely, there's no need for a new allocation as 459 * last page could have large enough tailroom. 460 */ 461 prog_adj = bpf_prog_realloc(prog, bpf_prog_size(insn_adj_cnt), 462 GFP_USER); 463 if (!prog_adj) 464 return ERR_PTR(-ENOMEM); 465 466 prog_adj->len = insn_adj_cnt; 467 468 /* Patching happens in 3 steps: 469 * 470 * 1) Move over tail of insnsi from next instruction onwards, 471 * so we can patch the single target insn with one or more 472 * new ones (patching is always from 1 to n insns, n > 0). 473 * 2) Inject new instructions at the target location. 474 * 3) Adjust branch offsets if necessary. 475 */ 476 insn_rest = insn_adj_cnt - off - len; 477 478 memmove(prog_adj->insnsi + off + len, prog_adj->insnsi + off + 1, 479 sizeof(*patch) * insn_rest); 480 memcpy(prog_adj->insnsi + off, patch, sizeof(*patch) * len); 481 482 /* We are guaranteed to not fail at this point, otherwise 483 * the ship has sailed to reverse to the original state. An 484 * overflow cannot happen at this point. 485 */ 486 BUG_ON(bpf_adj_branches(prog_adj, off, off + 1, off + len, false)); 487 488 bpf_adj_linfo(prog_adj, off, insn_delta); 489 490 return prog_adj; 491 } 492 493 int bpf_remove_insns(struct bpf_prog *prog, u32 off, u32 cnt) 494 { 495 /* Branch offsets can't overflow when program is shrinking, no need 496 * to call bpf_adj_branches(..., true) here 497 */ 498 memmove(prog->insnsi + off, prog->insnsi + off + cnt, 499 sizeof(struct bpf_insn) * (prog->len - off - cnt)); 500 prog->len -= cnt; 501 502 return WARN_ON_ONCE(bpf_adj_branches(prog, off, off + cnt, off, false)); 503 } 504 505 static void bpf_prog_kallsyms_del_subprogs(struct bpf_prog *fp) 506 { 507 int i; 508 509 for (i = 0; i < fp->aux->func_cnt; i++) 510 bpf_prog_kallsyms_del(fp->aux->func[i]); 511 } 512 513 void bpf_prog_kallsyms_del_all(struct bpf_prog *fp) 514 { 515 bpf_prog_kallsyms_del_subprogs(fp); 516 bpf_prog_kallsyms_del(fp); 517 } 518 519 #ifdef CONFIG_BPF_JIT 520 /* All BPF JIT sysctl knobs here. */ 521 int bpf_jit_enable __read_mostly = IS_BUILTIN(CONFIG_BPF_JIT_DEFAULT_ON); 522 int bpf_jit_kallsyms __read_mostly = IS_BUILTIN(CONFIG_BPF_JIT_DEFAULT_ON); 523 int bpf_jit_harden __read_mostly; 524 long bpf_jit_limit __read_mostly; 525 526 static void 527 bpf_prog_ksym_set_addr(struct bpf_prog *prog) 528 { 529 const struct bpf_binary_header *hdr = bpf_jit_binary_hdr(prog); 530 unsigned long addr = (unsigned long)hdr; 531 532 WARN_ON_ONCE(!bpf_prog_ebpf_jited(prog)); 533 534 prog->aux->ksym.start = (unsigned long) prog->bpf_func; 535 prog->aux->ksym.end = addr + hdr->pages * PAGE_SIZE; 536 } 537 538 static void 539 bpf_prog_ksym_set_name(struct bpf_prog *prog) 540 { 541 char *sym = prog->aux->ksym.name; 542 const char *end = sym + KSYM_NAME_LEN; 543 const struct btf_type *type; 544 const char *func_name; 545 546 BUILD_BUG_ON(sizeof("bpf_prog_") + 547 sizeof(prog->tag) * 2 + 548 /* name has been null terminated. 549 * We should need +1 for the '_' preceding 550 * the name. However, the null character 551 * is double counted between the name and the 552 * sizeof("bpf_prog_") above, so we omit 553 * the +1 here. 554 */ 555 sizeof(prog->aux->name) > KSYM_NAME_LEN); 556 557 sym += snprintf(sym, KSYM_NAME_LEN, "bpf_prog_"); 558 sym = bin2hex(sym, prog->tag, sizeof(prog->tag)); 559 560 /* prog->aux->name will be ignored if full btf name is available */ 561 if (prog->aux->func_info_cnt) { 562 type = btf_type_by_id(prog->aux->btf, 563 prog->aux->func_info[prog->aux->func_idx].type_id); 564 func_name = btf_name_by_offset(prog->aux->btf, type->name_off); 565 snprintf(sym, (size_t)(end - sym), "_%s", func_name); 566 return; 567 } 568 569 if (prog->aux->name[0]) 570 snprintf(sym, (size_t)(end - sym), "_%s", prog->aux->name); 571 else 572 *sym = 0; 573 } 574 575 static unsigned long bpf_get_ksym_start(struct latch_tree_node *n) 576 { 577 return container_of(n, struct bpf_ksym, tnode)->start; 578 } 579 580 static __always_inline bool bpf_tree_less(struct latch_tree_node *a, 581 struct latch_tree_node *b) 582 { 583 return bpf_get_ksym_start(a) < bpf_get_ksym_start(b); 584 } 585 586 static __always_inline int bpf_tree_comp(void *key, struct latch_tree_node *n) 587 { 588 unsigned long val = (unsigned long)key; 589 const struct bpf_ksym *ksym; 590 591 ksym = container_of(n, struct bpf_ksym, tnode); 592 593 if (val < ksym->start) 594 return -1; 595 if (val >= ksym->end) 596 return 1; 597 598 return 0; 599 } 600 601 static const struct latch_tree_ops bpf_tree_ops = { 602 .less = bpf_tree_less, 603 .comp = bpf_tree_comp, 604 }; 605 606 static DEFINE_SPINLOCK(bpf_lock); 607 static LIST_HEAD(bpf_kallsyms); 608 static struct latch_tree_root bpf_tree __cacheline_aligned; 609 610 void bpf_ksym_add(struct bpf_ksym *ksym) 611 { 612 spin_lock_bh(&bpf_lock); 613 WARN_ON_ONCE(!list_empty(&ksym->lnode)); 614 list_add_tail_rcu(&ksym->lnode, &bpf_kallsyms); 615 latch_tree_insert(&ksym->tnode, &bpf_tree, &bpf_tree_ops); 616 spin_unlock_bh(&bpf_lock); 617 } 618 619 static void __bpf_ksym_del(struct bpf_ksym *ksym) 620 { 621 if (list_empty(&ksym->lnode)) 622 return; 623 624 latch_tree_erase(&ksym->tnode, &bpf_tree, &bpf_tree_ops); 625 list_del_rcu(&ksym->lnode); 626 } 627 628 void bpf_ksym_del(struct bpf_ksym *ksym) 629 { 630 spin_lock_bh(&bpf_lock); 631 __bpf_ksym_del(ksym); 632 spin_unlock_bh(&bpf_lock); 633 } 634 635 static bool bpf_prog_kallsyms_candidate(const struct bpf_prog *fp) 636 { 637 return fp->jited && !bpf_prog_was_classic(fp); 638 } 639 640 static bool bpf_prog_kallsyms_verify_off(const struct bpf_prog *fp) 641 { 642 return list_empty(&fp->aux->ksym.lnode) || 643 fp->aux->ksym.lnode.prev == LIST_POISON2; 644 } 645 646 void bpf_prog_kallsyms_add(struct bpf_prog *fp) 647 { 648 if (!bpf_prog_kallsyms_candidate(fp) || 649 !bpf_capable()) 650 return; 651 652 bpf_prog_ksym_set_addr(fp); 653 bpf_prog_ksym_set_name(fp); 654 fp->aux->ksym.prog = true; 655 656 bpf_ksym_add(&fp->aux->ksym); 657 } 658 659 void bpf_prog_kallsyms_del(struct bpf_prog *fp) 660 { 661 if (!bpf_prog_kallsyms_candidate(fp)) 662 return; 663 664 bpf_ksym_del(&fp->aux->ksym); 665 } 666 667 static struct bpf_ksym *bpf_ksym_find(unsigned long addr) 668 { 669 struct latch_tree_node *n; 670 671 n = latch_tree_find((void *)addr, &bpf_tree, &bpf_tree_ops); 672 return n ? container_of(n, struct bpf_ksym, tnode) : NULL; 673 } 674 675 const char *__bpf_address_lookup(unsigned long addr, unsigned long *size, 676 unsigned long *off, char *sym) 677 { 678 struct bpf_ksym *ksym; 679 char *ret = NULL; 680 681 rcu_read_lock(); 682 ksym = bpf_ksym_find(addr); 683 if (ksym) { 684 unsigned long symbol_start = ksym->start; 685 unsigned long symbol_end = ksym->end; 686 687 strncpy(sym, ksym->name, KSYM_NAME_LEN); 688 689 ret = sym; 690 if (size) 691 *size = symbol_end - symbol_start; 692 if (off) 693 *off = addr - symbol_start; 694 } 695 rcu_read_unlock(); 696 697 return ret; 698 } 699 700 bool is_bpf_text_address(unsigned long addr) 701 { 702 bool ret; 703 704 rcu_read_lock(); 705 ret = bpf_ksym_find(addr) != NULL; 706 rcu_read_unlock(); 707 708 return ret; 709 } 710 711 static struct bpf_prog *bpf_prog_ksym_find(unsigned long addr) 712 { 713 struct bpf_ksym *ksym = bpf_ksym_find(addr); 714 715 return ksym && ksym->prog ? 716 container_of(ksym, struct bpf_prog_aux, ksym)->prog : 717 NULL; 718 } 719 720 const struct exception_table_entry *search_bpf_extables(unsigned long addr) 721 { 722 const struct exception_table_entry *e = NULL; 723 struct bpf_prog *prog; 724 725 rcu_read_lock(); 726 prog = bpf_prog_ksym_find(addr); 727 if (!prog) 728 goto out; 729 if (!prog->aux->num_exentries) 730 goto out; 731 732 e = search_extable(prog->aux->extable, prog->aux->num_exentries, addr); 733 out: 734 rcu_read_unlock(); 735 return e; 736 } 737 738 int bpf_get_kallsym(unsigned int symnum, unsigned long *value, char *type, 739 char *sym) 740 { 741 struct bpf_ksym *ksym; 742 unsigned int it = 0; 743 int ret = -ERANGE; 744 745 if (!bpf_jit_kallsyms_enabled()) 746 return ret; 747 748 rcu_read_lock(); 749 list_for_each_entry_rcu(ksym, &bpf_kallsyms, lnode) { 750 if (it++ != symnum) 751 continue; 752 753 strncpy(sym, ksym->name, KSYM_NAME_LEN); 754 755 *value = ksym->start; 756 *type = BPF_SYM_ELF_TYPE; 757 758 ret = 0; 759 break; 760 } 761 rcu_read_unlock(); 762 763 return ret; 764 } 765 766 int bpf_jit_add_poke_descriptor(struct bpf_prog *prog, 767 struct bpf_jit_poke_descriptor *poke) 768 { 769 struct bpf_jit_poke_descriptor *tab = prog->aux->poke_tab; 770 static const u32 poke_tab_max = 1024; 771 u32 slot = prog->aux->size_poke_tab; 772 u32 size = slot + 1; 773 774 if (size > poke_tab_max) 775 return -ENOSPC; 776 if (poke->ip || poke->ip_stable || poke->adj_off) 777 return -EINVAL; 778 779 switch (poke->reason) { 780 case BPF_POKE_REASON_TAIL_CALL: 781 if (!poke->tail_call.map) 782 return -EINVAL; 783 break; 784 default: 785 return -EINVAL; 786 } 787 788 tab = krealloc(tab, size * sizeof(*poke), GFP_KERNEL); 789 if (!tab) 790 return -ENOMEM; 791 792 memcpy(&tab[slot], poke, sizeof(*poke)); 793 prog->aux->size_poke_tab = size; 794 prog->aux->poke_tab = tab; 795 796 return slot; 797 } 798 799 static atomic_long_t bpf_jit_current; 800 801 /* Can be overridden by an arch's JIT compiler if it has a custom, 802 * dedicated BPF backend memory area, or if neither of the two 803 * below apply. 804 */ 805 u64 __weak bpf_jit_alloc_exec_limit(void) 806 { 807 #if defined(MODULES_VADDR) 808 return MODULES_END - MODULES_VADDR; 809 #else 810 return VMALLOC_END - VMALLOC_START; 811 #endif 812 } 813 814 static int __init bpf_jit_charge_init(void) 815 { 816 /* Only used as heuristic here to derive limit. */ 817 bpf_jit_limit = min_t(u64, round_up(bpf_jit_alloc_exec_limit() >> 2, 818 PAGE_SIZE), LONG_MAX); 819 return 0; 820 } 821 pure_initcall(bpf_jit_charge_init); 822 823 static int bpf_jit_charge_modmem(u32 pages) 824 { 825 if (atomic_long_add_return(pages, &bpf_jit_current) > 826 (bpf_jit_limit >> PAGE_SHIFT)) { 827 if (!capable(CAP_SYS_ADMIN)) { 828 atomic_long_sub(pages, &bpf_jit_current); 829 return -EPERM; 830 } 831 } 832 833 return 0; 834 } 835 836 static void bpf_jit_uncharge_modmem(u32 pages) 837 { 838 atomic_long_sub(pages, &bpf_jit_current); 839 } 840 841 void *__weak bpf_jit_alloc_exec(unsigned long size) 842 { 843 return module_alloc(size); 844 } 845 846 void __weak bpf_jit_free_exec(void *addr) 847 { 848 module_memfree(addr); 849 } 850 851 struct bpf_binary_header * 852 bpf_jit_binary_alloc(unsigned int proglen, u8 **image_ptr, 853 unsigned int alignment, 854 bpf_jit_fill_hole_t bpf_fill_ill_insns) 855 { 856 struct bpf_binary_header *hdr; 857 u32 size, hole, start, pages; 858 859 WARN_ON_ONCE(!is_power_of_2(alignment) || 860 alignment > BPF_IMAGE_ALIGNMENT); 861 862 /* Most of BPF filters are really small, but if some of them 863 * fill a page, allow at least 128 extra bytes to insert a 864 * random section of illegal instructions. 865 */ 866 size = round_up(proglen + sizeof(*hdr) + 128, PAGE_SIZE); 867 pages = size / PAGE_SIZE; 868 869 if (bpf_jit_charge_modmem(pages)) 870 return NULL; 871 hdr = bpf_jit_alloc_exec(size); 872 if (!hdr) { 873 bpf_jit_uncharge_modmem(pages); 874 return NULL; 875 } 876 877 /* Fill space with illegal/arch-dep instructions. */ 878 bpf_fill_ill_insns(hdr, size); 879 880 hdr->pages = pages; 881 hole = min_t(unsigned int, size - (proglen + sizeof(*hdr)), 882 PAGE_SIZE - sizeof(*hdr)); 883 start = (get_random_int() % hole) & ~(alignment - 1); 884 885 /* Leave a random number of instructions before BPF code. */ 886 *image_ptr = &hdr->image[start]; 887 888 return hdr; 889 } 890 891 void bpf_jit_binary_free(struct bpf_binary_header *hdr) 892 { 893 u32 pages = hdr->pages; 894 895 bpf_jit_free_exec(hdr); 896 bpf_jit_uncharge_modmem(pages); 897 } 898 899 /* This symbol is only overridden by archs that have different 900 * requirements than the usual eBPF JITs, f.e. when they only 901 * implement cBPF JIT, do not set images read-only, etc. 902 */ 903 void __weak bpf_jit_free(struct bpf_prog *fp) 904 { 905 if (fp->jited) { 906 struct bpf_binary_header *hdr = bpf_jit_binary_hdr(fp); 907 908 bpf_jit_binary_free(hdr); 909 910 WARN_ON_ONCE(!bpf_prog_kallsyms_verify_off(fp)); 911 } 912 913 bpf_prog_unlock_free(fp); 914 } 915 916 int bpf_jit_get_func_addr(const struct bpf_prog *prog, 917 const struct bpf_insn *insn, bool extra_pass, 918 u64 *func_addr, bool *func_addr_fixed) 919 { 920 s16 off = insn->off; 921 s32 imm = insn->imm; 922 u8 *addr; 923 924 *func_addr_fixed = insn->src_reg != BPF_PSEUDO_CALL; 925 if (!*func_addr_fixed) { 926 /* Place-holder address till the last pass has collected 927 * all addresses for JITed subprograms in which case we 928 * can pick them up from prog->aux. 929 */ 930 if (!extra_pass) 931 addr = NULL; 932 else if (prog->aux->func && 933 off >= 0 && off < prog->aux->func_cnt) 934 addr = (u8 *)prog->aux->func[off]->bpf_func; 935 else 936 return -EINVAL; 937 } else { 938 /* Address of a BPF helper call. Since part of the core 939 * kernel, it's always at a fixed location. __bpf_call_base 940 * and the helper with imm relative to it are both in core 941 * kernel. 942 */ 943 addr = (u8 *)__bpf_call_base + imm; 944 } 945 946 *func_addr = (unsigned long)addr; 947 return 0; 948 } 949 950 static int bpf_jit_blind_insn(const struct bpf_insn *from, 951 const struct bpf_insn *aux, 952 struct bpf_insn *to_buff, 953 bool emit_zext) 954 { 955 struct bpf_insn *to = to_buff; 956 u32 imm_rnd = get_random_int(); 957 s16 off; 958 959 BUILD_BUG_ON(BPF_REG_AX + 1 != MAX_BPF_JIT_REG); 960 BUILD_BUG_ON(MAX_BPF_REG + 1 != MAX_BPF_JIT_REG); 961 962 /* Constraints on AX register: 963 * 964 * AX register is inaccessible from user space. It is mapped in 965 * all JITs, and used here for constant blinding rewrites. It is 966 * typically "stateless" meaning its contents are only valid within 967 * the executed instruction, but not across several instructions. 968 * There are a few exceptions however which are further detailed 969 * below. 970 * 971 * Constant blinding is only used by JITs, not in the interpreter. 972 * The interpreter uses AX in some occasions as a local temporary 973 * register e.g. in DIV or MOD instructions. 974 * 975 * In restricted circumstances, the verifier can also use the AX 976 * register for rewrites as long as they do not interfere with 977 * the above cases! 978 */ 979 if (from->dst_reg == BPF_REG_AX || from->src_reg == BPF_REG_AX) 980 goto out; 981 982 if (from->imm == 0 && 983 (from->code == (BPF_ALU | BPF_MOV | BPF_K) || 984 from->code == (BPF_ALU64 | BPF_MOV | BPF_K))) { 985 *to++ = BPF_ALU64_REG(BPF_XOR, from->dst_reg, from->dst_reg); 986 goto out; 987 } 988 989 switch (from->code) { 990 case BPF_ALU | BPF_ADD | BPF_K: 991 case BPF_ALU | BPF_SUB | BPF_K: 992 case BPF_ALU | BPF_AND | BPF_K: 993 case BPF_ALU | BPF_OR | BPF_K: 994 case BPF_ALU | BPF_XOR | BPF_K: 995 case BPF_ALU | BPF_MUL | BPF_K: 996 case BPF_ALU | BPF_MOV | BPF_K: 997 case BPF_ALU | BPF_DIV | BPF_K: 998 case BPF_ALU | BPF_MOD | BPF_K: 999 *to++ = BPF_ALU32_IMM(BPF_MOV, BPF_REG_AX, imm_rnd ^ from->imm); 1000 *to++ = BPF_ALU32_IMM(BPF_XOR, BPF_REG_AX, imm_rnd); 1001 *to++ = BPF_ALU32_REG(from->code, from->dst_reg, BPF_REG_AX); 1002 break; 1003 1004 case BPF_ALU64 | BPF_ADD | BPF_K: 1005 case BPF_ALU64 | BPF_SUB | BPF_K: 1006 case BPF_ALU64 | BPF_AND | BPF_K: 1007 case BPF_ALU64 | BPF_OR | BPF_K: 1008 case BPF_ALU64 | BPF_XOR | BPF_K: 1009 case BPF_ALU64 | BPF_MUL | BPF_K: 1010 case BPF_ALU64 | BPF_MOV | BPF_K: 1011 case BPF_ALU64 | BPF_DIV | BPF_K: 1012 case BPF_ALU64 | BPF_MOD | BPF_K: 1013 *to++ = BPF_ALU64_IMM(BPF_MOV, BPF_REG_AX, imm_rnd ^ from->imm); 1014 *to++ = BPF_ALU64_IMM(BPF_XOR, BPF_REG_AX, imm_rnd); 1015 *to++ = BPF_ALU64_REG(from->code, from->dst_reg, BPF_REG_AX); 1016 break; 1017 1018 case BPF_JMP | BPF_JEQ | BPF_K: 1019 case BPF_JMP | BPF_JNE | BPF_K: 1020 case BPF_JMP | BPF_JGT | BPF_K: 1021 case BPF_JMP | BPF_JLT | BPF_K: 1022 case BPF_JMP | BPF_JGE | BPF_K: 1023 case BPF_JMP | BPF_JLE | BPF_K: 1024 case BPF_JMP | BPF_JSGT | BPF_K: 1025 case BPF_JMP | BPF_JSLT | BPF_K: 1026 case BPF_JMP | BPF_JSGE | BPF_K: 1027 case BPF_JMP | BPF_JSLE | BPF_K: 1028 case BPF_JMP | BPF_JSET | BPF_K: 1029 /* Accommodate for extra offset in case of a backjump. */ 1030 off = from->off; 1031 if (off < 0) 1032 off -= 2; 1033 *to++ = BPF_ALU64_IMM(BPF_MOV, BPF_REG_AX, imm_rnd ^ from->imm); 1034 *to++ = BPF_ALU64_IMM(BPF_XOR, BPF_REG_AX, imm_rnd); 1035 *to++ = BPF_JMP_REG(from->code, from->dst_reg, BPF_REG_AX, off); 1036 break; 1037 1038 case BPF_JMP32 | BPF_JEQ | BPF_K: 1039 case BPF_JMP32 | BPF_JNE | BPF_K: 1040 case BPF_JMP32 | BPF_JGT | BPF_K: 1041 case BPF_JMP32 | BPF_JLT | BPF_K: 1042 case BPF_JMP32 | BPF_JGE | BPF_K: 1043 case BPF_JMP32 | BPF_JLE | BPF_K: 1044 case BPF_JMP32 | BPF_JSGT | BPF_K: 1045 case BPF_JMP32 | BPF_JSLT | BPF_K: 1046 case BPF_JMP32 | BPF_JSGE | BPF_K: 1047 case BPF_JMP32 | BPF_JSLE | BPF_K: 1048 case BPF_JMP32 | BPF_JSET | BPF_K: 1049 /* Accommodate for extra offset in case of a backjump. */ 1050 off = from->off; 1051 if (off < 0) 1052 off -= 2; 1053 *to++ = BPF_ALU32_IMM(BPF_MOV, BPF_REG_AX, imm_rnd ^ from->imm); 1054 *to++ = BPF_ALU32_IMM(BPF_XOR, BPF_REG_AX, imm_rnd); 1055 *to++ = BPF_JMP32_REG(from->code, from->dst_reg, BPF_REG_AX, 1056 off); 1057 break; 1058 1059 case BPF_LD | BPF_IMM | BPF_DW: 1060 *to++ = BPF_ALU64_IMM(BPF_MOV, BPF_REG_AX, imm_rnd ^ aux[1].imm); 1061 *to++ = BPF_ALU64_IMM(BPF_XOR, BPF_REG_AX, imm_rnd); 1062 *to++ = BPF_ALU64_IMM(BPF_LSH, BPF_REG_AX, 32); 1063 *to++ = BPF_ALU64_REG(BPF_MOV, aux[0].dst_reg, BPF_REG_AX); 1064 break; 1065 case 0: /* Part 2 of BPF_LD | BPF_IMM | BPF_DW. */ 1066 *to++ = BPF_ALU32_IMM(BPF_MOV, BPF_REG_AX, imm_rnd ^ aux[0].imm); 1067 *to++ = BPF_ALU32_IMM(BPF_XOR, BPF_REG_AX, imm_rnd); 1068 if (emit_zext) 1069 *to++ = BPF_ZEXT_REG(BPF_REG_AX); 1070 *to++ = BPF_ALU64_REG(BPF_OR, aux[0].dst_reg, BPF_REG_AX); 1071 break; 1072 1073 case BPF_ST | BPF_MEM | BPF_DW: 1074 case BPF_ST | BPF_MEM | BPF_W: 1075 case BPF_ST | BPF_MEM | BPF_H: 1076 case BPF_ST | BPF_MEM | BPF_B: 1077 *to++ = BPF_ALU64_IMM(BPF_MOV, BPF_REG_AX, imm_rnd ^ from->imm); 1078 *to++ = BPF_ALU64_IMM(BPF_XOR, BPF_REG_AX, imm_rnd); 1079 *to++ = BPF_STX_MEM(from->code, from->dst_reg, BPF_REG_AX, from->off); 1080 break; 1081 } 1082 out: 1083 return to - to_buff; 1084 } 1085 1086 static struct bpf_prog *bpf_prog_clone_create(struct bpf_prog *fp_other, 1087 gfp_t gfp_extra_flags) 1088 { 1089 gfp_t gfp_flags = GFP_KERNEL | __GFP_ZERO | gfp_extra_flags; 1090 struct bpf_prog *fp; 1091 1092 fp = __vmalloc(fp_other->pages * PAGE_SIZE, gfp_flags); 1093 if (fp != NULL) { 1094 /* aux->prog still points to the fp_other one, so 1095 * when promoting the clone to the real program, 1096 * this still needs to be adapted. 1097 */ 1098 memcpy(fp, fp_other, fp_other->pages * PAGE_SIZE); 1099 } 1100 1101 return fp; 1102 } 1103 1104 static void bpf_prog_clone_free(struct bpf_prog *fp) 1105 { 1106 /* aux was stolen by the other clone, so we cannot free 1107 * it from this path! It will be freed eventually by the 1108 * other program on release. 1109 * 1110 * At this point, we don't need a deferred release since 1111 * clone is guaranteed to not be locked. 1112 */ 1113 fp->aux = NULL; 1114 __bpf_prog_free(fp); 1115 } 1116 1117 void bpf_jit_prog_release_other(struct bpf_prog *fp, struct bpf_prog *fp_other) 1118 { 1119 /* We have to repoint aux->prog to self, as we don't 1120 * know whether fp here is the clone or the original. 1121 */ 1122 fp->aux->prog = fp; 1123 bpf_prog_clone_free(fp_other); 1124 } 1125 1126 struct bpf_prog *bpf_jit_blind_constants(struct bpf_prog *prog) 1127 { 1128 struct bpf_insn insn_buff[16], aux[2]; 1129 struct bpf_prog *clone, *tmp; 1130 int insn_delta, insn_cnt; 1131 struct bpf_insn *insn; 1132 int i, rewritten; 1133 1134 if (!bpf_jit_blinding_enabled(prog) || prog->blinded) 1135 return prog; 1136 1137 clone = bpf_prog_clone_create(prog, GFP_USER); 1138 if (!clone) 1139 return ERR_PTR(-ENOMEM); 1140 1141 insn_cnt = clone->len; 1142 insn = clone->insnsi; 1143 1144 for (i = 0; i < insn_cnt; i++, insn++) { 1145 /* We temporarily need to hold the original ld64 insn 1146 * so that we can still access the first part in the 1147 * second blinding run. 1148 */ 1149 if (insn[0].code == (BPF_LD | BPF_IMM | BPF_DW) && 1150 insn[1].code == 0) 1151 memcpy(aux, insn, sizeof(aux)); 1152 1153 rewritten = bpf_jit_blind_insn(insn, aux, insn_buff, 1154 clone->aux->verifier_zext); 1155 if (!rewritten) 1156 continue; 1157 1158 tmp = bpf_patch_insn_single(clone, i, insn_buff, rewritten); 1159 if (IS_ERR(tmp)) { 1160 /* Patching may have repointed aux->prog during 1161 * realloc from the original one, so we need to 1162 * fix it up here on error. 1163 */ 1164 bpf_jit_prog_release_other(prog, clone); 1165 return tmp; 1166 } 1167 1168 clone = tmp; 1169 insn_delta = rewritten - 1; 1170 1171 /* Walk new program and skip insns we just inserted. */ 1172 insn = clone->insnsi + i + insn_delta; 1173 insn_cnt += insn_delta; 1174 i += insn_delta; 1175 } 1176 1177 clone->blinded = 1; 1178 return clone; 1179 } 1180 #endif /* CONFIG_BPF_JIT */ 1181 1182 /* Base function for offset calculation. Needs to go into .text section, 1183 * therefore keeping it non-static as well; will also be used by JITs 1184 * anyway later on, so do not let the compiler omit it. This also needs 1185 * to go into kallsyms for correlation from e.g. bpftool, so naming 1186 * must not change. 1187 */ 1188 noinline u64 __bpf_call_base(u64 r1, u64 r2, u64 r3, u64 r4, u64 r5) 1189 { 1190 return 0; 1191 } 1192 EXPORT_SYMBOL_GPL(__bpf_call_base); 1193 1194 /* All UAPI available opcodes. */ 1195 #define BPF_INSN_MAP(INSN_2, INSN_3) \ 1196 /* 32 bit ALU operations. */ \ 1197 /* Register based. */ \ 1198 INSN_3(ALU, ADD, X), \ 1199 INSN_3(ALU, SUB, X), \ 1200 INSN_3(ALU, AND, X), \ 1201 INSN_3(ALU, OR, X), \ 1202 INSN_3(ALU, LSH, X), \ 1203 INSN_3(ALU, RSH, X), \ 1204 INSN_3(ALU, XOR, X), \ 1205 INSN_3(ALU, MUL, X), \ 1206 INSN_3(ALU, MOV, X), \ 1207 INSN_3(ALU, ARSH, X), \ 1208 INSN_3(ALU, DIV, X), \ 1209 INSN_3(ALU, MOD, X), \ 1210 INSN_2(ALU, NEG), \ 1211 INSN_3(ALU, END, TO_BE), \ 1212 INSN_3(ALU, END, TO_LE), \ 1213 /* Immediate based. */ \ 1214 INSN_3(ALU, ADD, K), \ 1215 INSN_3(ALU, SUB, K), \ 1216 INSN_3(ALU, AND, K), \ 1217 INSN_3(ALU, OR, K), \ 1218 INSN_3(ALU, LSH, K), \ 1219 INSN_3(ALU, RSH, K), \ 1220 INSN_3(ALU, XOR, K), \ 1221 INSN_3(ALU, MUL, K), \ 1222 INSN_3(ALU, MOV, K), \ 1223 INSN_3(ALU, ARSH, K), \ 1224 INSN_3(ALU, DIV, K), \ 1225 INSN_3(ALU, MOD, K), \ 1226 /* 64 bit ALU operations. */ \ 1227 /* Register based. */ \ 1228 INSN_3(ALU64, ADD, X), \ 1229 INSN_3(ALU64, SUB, X), \ 1230 INSN_3(ALU64, AND, X), \ 1231 INSN_3(ALU64, OR, X), \ 1232 INSN_3(ALU64, LSH, X), \ 1233 INSN_3(ALU64, RSH, X), \ 1234 INSN_3(ALU64, XOR, X), \ 1235 INSN_3(ALU64, MUL, X), \ 1236 INSN_3(ALU64, MOV, X), \ 1237 INSN_3(ALU64, ARSH, X), \ 1238 INSN_3(ALU64, DIV, X), \ 1239 INSN_3(ALU64, MOD, X), \ 1240 INSN_2(ALU64, NEG), \ 1241 /* Immediate based. */ \ 1242 INSN_3(ALU64, ADD, K), \ 1243 INSN_3(ALU64, SUB, K), \ 1244 INSN_3(ALU64, AND, K), \ 1245 INSN_3(ALU64, OR, K), \ 1246 INSN_3(ALU64, LSH, K), \ 1247 INSN_3(ALU64, RSH, K), \ 1248 INSN_3(ALU64, XOR, K), \ 1249 INSN_3(ALU64, MUL, K), \ 1250 INSN_3(ALU64, MOV, K), \ 1251 INSN_3(ALU64, ARSH, K), \ 1252 INSN_3(ALU64, DIV, K), \ 1253 INSN_3(ALU64, MOD, K), \ 1254 /* Call instruction. */ \ 1255 INSN_2(JMP, CALL), \ 1256 /* Exit instruction. */ \ 1257 INSN_2(JMP, EXIT), \ 1258 /* 32-bit Jump instructions. */ \ 1259 /* Register based. */ \ 1260 INSN_3(JMP32, JEQ, X), \ 1261 INSN_3(JMP32, JNE, X), \ 1262 INSN_3(JMP32, JGT, X), \ 1263 INSN_3(JMP32, JLT, X), \ 1264 INSN_3(JMP32, JGE, X), \ 1265 INSN_3(JMP32, JLE, X), \ 1266 INSN_3(JMP32, JSGT, X), \ 1267 INSN_3(JMP32, JSLT, X), \ 1268 INSN_3(JMP32, JSGE, X), \ 1269 INSN_3(JMP32, JSLE, X), \ 1270 INSN_3(JMP32, JSET, X), \ 1271 /* Immediate based. */ \ 1272 INSN_3(JMP32, JEQ, K), \ 1273 INSN_3(JMP32, JNE, K), \ 1274 INSN_3(JMP32, JGT, K), \ 1275 INSN_3(JMP32, JLT, K), \ 1276 INSN_3(JMP32, JGE, K), \ 1277 INSN_3(JMP32, JLE, K), \ 1278 INSN_3(JMP32, JSGT, K), \ 1279 INSN_3(JMP32, JSLT, K), \ 1280 INSN_3(JMP32, JSGE, K), \ 1281 INSN_3(JMP32, JSLE, K), \ 1282 INSN_3(JMP32, JSET, K), \ 1283 /* Jump instructions. */ \ 1284 /* Register based. */ \ 1285 INSN_3(JMP, JEQ, X), \ 1286 INSN_3(JMP, JNE, X), \ 1287 INSN_3(JMP, JGT, X), \ 1288 INSN_3(JMP, JLT, X), \ 1289 INSN_3(JMP, JGE, X), \ 1290 INSN_3(JMP, JLE, X), \ 1291 INSN_3(JMP, JSGT, X), \ 1292 INSN_3(JMP, JSLT, X), \ 1293 INSN_3(JMP, JSGE, X), \ 1294 INSN_3(JMP, JSLE, X), \ 1295 INSN_3(JMP, JSET, X), \ 1296 /* Immediate based. */ \ 1297 INSN_3(JMP, JEQ, K), \ 1298 INSN_3(JMP, JNE, K), \ 1299 INSN_3(JMP, JGT, K), \ 1300 INSN_3(JMP, JLT, K), \ 1301 INSN_3(JMP, JGE, K), \ 1302 INSN_3(JMP, JLE, K), \ 1303 INSN_3(JMP, JSGT, K), \ 1304 INSN_3(JMP, JSLT, K), \ 1305 INSN_3(JMP, JSGE, K), \ 1306 INSN_3(JMP, JSLE, K), \ 1307 INSN_3(JMP, JSET, K), \ 1308 INSN_2(JMP, JA), \ 1309 /* Store instructions. */ \ 1310 /* Register based. */ \ 1311 INSN_3(STX, MEM, B), \ 1312 INSN_3(STX, MEM, H), \ 1313 INSN_3(STX, MEM, W), \ 1314 INSN_3(STX, MEM, DW), \ 1315 INSN_3(STX, XADD, W), \ 1316 INSN_3(STX, XADD, DW), \ 1317 /* Immediate based. */ \ 1318 INSN_3(ST, MEM, B), \ 1319 INSN_3(ST, MEM, H), \ 1320 INSN_3(ST, MEM, W), \ 1321 INSN_3(ST, MEM, DW), \ 1322 /* Load instructions. */ \ 1323 /* Register based. */ \ 1324 INSN_3(LDX, MEM, B), \ 1325 INSN_3(LDX, MEM, H), \ 1326 INSN_3(LDX, MEM, W), \ 1327 INSN_3(LDX, MEM, DW), \ 1328 /* Immediate based. */ \ 1329 INSN_3(LD, IMM, DW) 1330 1331 bool bpf_opcode_in_insntable(u8 code) 1332 { 1333 #define BPF_INSN_2_TBL(x, y) [BPF_##x | BPF_##y] = true 1334 #define BPF_INSN_3_TBL(x, y, z) [BPF_##x | BPF_##y | BPF_##z] = true 1335 static const bool public_insntable[256] = { 1336 [0 ... 255] = false, 1337 /* Now overwrite non-defaults ... */ 1338 BPF_INSN_MAP(BPF_INSN_2_TBL, BPF_INSN_3_TBL), 1339 /* UAPI exposed, but rewritten opcodes. cBPF carry-over. */ 1340 [BPF_LD | BPF_ABS | BPF_B] = true, 1341 [BPF_LD | BPF_ABS | BPF_H] = true, 1342 [BPF_LD | BPF_ABS | BPF_W] = true, 1343 [BPF_LD | BPF_IND | BPF_B] = true, 1344 [BPF_LD | BPF_IND | BPF_H] = true, 1345 [BPF_LD | BPF_IND | BPF_W] = true, 1346 }; 1347 #undef BPF_INSN_3_TBL 1348 #undef BPF_INSN_2_TBL 1349 return public_insntable[code]; 1350 } 1351 1352 #ifndef CONFIG_BPF_JIT_ALWAYS_ON 1353 u64 __weak bpf_probe_read_kernel(void *dst, u32 size, const void *unsafe_ptr) 1354 { 1355 memset(dst, 0, size); 1356 return -EFAULT; 1357 } 1358 1359 /** 1360 * __bpf_prog_run - run eBPF program on a given context 1361 * @regs: is the array of MAX_BPF_EXT_REG eBPF pseudo-registers 1362 * @insn: is the array of eBPF instructions 1363 * @stack: is the eBPF storage stack 1364 * 1365 * Decode and execute eBPF instructions. 1366 */ 1367 static u64 __no_fgcse ___bpf_prog_run(u64 *regs, const struct bpf_insn *insn, u64 *stack) 1368 { 1369 #define BPF_INSN_2_LBL(x, y) [BPF_##x | BPF_##y] = &&x##_##y 1370 #define BPF_INSN_3_LBL(x, y, z) [BPF_##x | BPF_##y | BPF_##z] = &&x##_##y##_##z 1371 static const void * const jumptable[256] __annotate_jump_table = { 1372 [0 ... 255] = &&default_label, 1373 /* Now overwrite non-defaults ... */ 1374 BPF_INSN_MAP(BPF_INSN_2_LBL, BPF_INSN_3_LBL), 1375 /* Non-UAPI available opcodes. */ 1376 [BPF_JMP | BPF_CALL_ARGS] = &&JMP_CALL_ARGS, 1377 [BPF_JMP | BPF_TAIL_CALL] = &&JMP_TAIL_CALL, 1378 [BPF_LDX | BPF_PROBE_MEM | BPF_B] = &&LDX_PROBE_MEM_B, 1379 [BPF_LDX | BPF_PROBE_MEM | BPF_H] = &&LDX_PROBE_MEM_H, 1380 [BPF_LDX | BPF_PROBE_MEM | BPF_W] = &&LDX_PROBE_MEM_W, 1381 [BPF_LDX | BPF_PROBE_MEM | BPF_DW] = &&LDX_PROBE_MEM_DW, 1382 }; 1383 #undef BPF_INSN_3_LBL 1384 #undef BPF_INSN_2_LBL 1385 u32 tail_call_cnt = 0; 1386 1387 #define CONT ({ insn++; goto select_insn; }) 1388 #define CONT_JMP ({ insn++; goto select_insn; }) 1389 1390 select_insn: 1391 goto *jumptable[insn->code]; 1392 1393 /* ALU */ 1394 #define ALU(OPCODE, OP) \ 1395 ALU64_##OPCODE##_X: \ 1396 DST = DST OP SRC; \ 1397 CONT; \ 1398 ALU_##OPCODE##_X: \ 1399 DST = (u32) DST OP (u32) SRC; \ 1400 CONT; \ 1401 ALU64_##OPCODE##_K: \ 1402 DST = DST OP IMM; \ 1403 CONT; \ 1404 ALU_##OPCODE##_K: \ 1405 DST = (u32) DST OP (u32) IMM; \ 1406 CONT; 1407 1408 ALU(ADD, +) 1409 ALU(SUB, -) 1410 ALU(AND, &) 1411 ALU(OR, |) 1412 ALU(LSH, <<) 1413 ALU(RSH, >>) 1414 ALU(XOR, ^) 1415 ALU(MUL, *) 1416 #undef ALU 1417 ALU_NEG: 1418 DST = (u32) -DST; 1419 CONT; 1420 ALU64_NEG: 1421 DST = -DST; 1422 CONT; 1423 ALU_MOV_X: 1424 DST = (u32) SRC; 1425 CONT; 1426 ALU_MOV_K: 1427 DST = (u32) IMM; 1428 CONT; 1429 ALU64_MOV_X: 1430 DST = SRC; 1431 CONT; 1432 ALU64_MOV_K: 1433 DST = IMM; 1434 CONT; 1435 LD_IMM_DW: 1436 DST = (u64) (u32) insn[0].imm | ((u64) (u32) insn[1].imm) << 32; 1437 insn++; 1438 CONT; 1439 ALU_ARSH_X: 1440 DST = (u64) (u32) (((s32) DST) >> SRC); 1441 CONT; 1442 ALU_ARSH_K: 1443 DST = (u64) (u32) (((s32) DST) >> IMM); 1444 CONT; 1445 ALU64_ARSH_X: 1446 (*(s64 *) &DST) >>= SRC; 1447 CONT; 1448 ALU64_ARSH_K: 1449 (*(s64 *) &DST) >>= IMM; 1450 CONT; 1451 ALU64_MOD_X: 1452 div64_u64_rem(DST, SRC, &AX); 1453 DST = AX; 1454 CONT; 1455 ALU_MOD_X: 1456 AX = (u32) DST; 1457 DST = do_div(AX, (u32) SRC); 1458 CONT; 1459 ALU64_MOD_K: 1460 div64_u64_rem(DST, IMM, &AX); 1461 DST = AX; 1462 CONT; 1463 ALU_MOD_K: 1464 AX = (u32) DST; 1465 DST = do_div(AX, (u32) IMM); 1466 CONT; 1467 ALU64_DIV_X: 1468 DST = div64_u64(DST, SRC); 1469 CONT; 1470 ALU_DIV_X: 1471 AX = (u32) DST; 1472 do_div(AX, (u32) SRC); 1473 DST = (u32) AX; 1474 CONT; 1475 ALU64_DIV_K: 1476 DST = div64_u64(DST, IMM); 1477 CONT; 1478 ALU_DIV_K: 1479 AX = (u32) DST; 1480 do_div(AX, (u32) IMM); 1481 DST = (u32) AX; 1482 CONT; 1483 ALU_END_TO_BE: 1484 switch (IMM) { 1485 case 16: 1486 DST = (__force u16) cpu_to_be16(DST); 1487 break; 1488 case 32: 1489 DST = (__force u32) cpu_to_be32(DST); 1490 break; 1491 case 64: 1492 DST = (__force u64) cpu_to_be64(DST); 1493 break; 1494 } 1495 CONT; 1496 ALU_END_TO_LE: 1497 switch (IMM) { 1498 case 16: 1499 DST = (__force u16) cpu_to_le16(DST); 1500 break; 1501 case 32: 1502 DST = (__force u32) cpu_to_le32(DST); 1503 break; 1504 case 64: 1505 DST = (__force u64) cpu_to_le64(DST); 1506 break; 1507 } 1508 CONT; 1509 1510 /* CALL */ 1511 JMP_CALL: 1512 /* Function call scratches BPF_R1-BPF_R5 registers, 1513 * preserves BPF_R6-BPF_R9, and stores return value 1514 * into BPF_R0. 1515 */ 1516 BPF_R0 = (__bpf_call_base + insn->imm)(BPF_R1, BPF_R2, BPF_R3, 1517 BPF_R4, BPF_R5); 1518 CONT; 1519 1520 JMP_CALL_ARGS: 1521 BPF_R0 = (__bpf_call_base_args + insn->imm)(BPF_R1, BPF_R2, 1522 BPF_R3, BPF_R4, 1523 BPF_R5, 1524 insn + insn->off + 1); 1525 CONT; 1526 1527 JMP_TAIL_CALL: { 1528 struct bpf_map *map = (struct bpf_map *) (unsigned long) BPF_R2; 1529 struct bpf_array *array = container_of(map, struct bpf_array, map); 1530 struct bpf_prog *prog; 1531 u32 index = BPF_R3; 1532 1533 if (unlikely(index >= array->map.max_entries)) 1534 goto out; 1535 if (unlikely(tail_call_cnt > MAX_TAIL_CALL_CNT)) 1536 goto out; 1537 1538 tail_call_cnt++; 1539 1540 prog = READ_ONCE(array->ptrs[index]); 1541 if (!prog) 1542 goto out; 1543 1544 /* ARG1 at this point is guaranteed to point to CTX from 1545 * the verifier side due to the fact that the tail call is 1546 * handled like a helper, that is, bpf_tail_call_proto, 1547 * where arg1_type is ARG_PTR_TO_CTX. 1548 */ 1549 insn = prog->insnsi; 1550 goto select_insn; 1551 out: 1552 CONT; 1553 } 1554 JMP_JA: 1555 insn += insn->off; 1556 CONT; 1557 JMP_EXIT: 1558 return BPF_R0; 1559 /* JMP */ 1560 #define COND_JMP(SIGN, OPCODE, CMP_OP) \ 1561 JMP_##OPCODE##_X: \ 1562 if ((SIGN##64) DST CMP_OP (SIGN##64) SRC) { \ 1563 insn += insn->off; \ 1564 CONT_JMP; \ 1565 } \ 1566 CONT; \ 1567 JMP32_##OPCODE##_X: \ 1568 if ((SIGN##32) DST CMP_OP (SIGN##32) SRC) { \ 1569 insn += insn->off; \ 1570 CONT_JMP; \ 1571 } \ 1572 CONT; \ 1573 JMP_##OPCODE##_K: \ 1574 if ((SIGN##64) DST CMP_OP (SIGN##64) IMM) { \ 1575 insn += insn->off; \ 1576 CONT_JMP; \ 1577 } \ 1578 CONT; \ 1579 JMP32_##OPCODE##_K: \ 1580 if ((SIGN##32) DST CMP_OP (SIGN##32) IMM) { \ 1581 insn += insn->off; \ 1582 CONT_JMP; \ 1583 } \ 1584 CONT; 1585 COND_JMP(u, JEQ, ==) 1586 COND_JMP(u, JNE, !=) 1587 COND_JMP(u, JGT, >) 1588 COND_JMP(u, JLT, <) 1589 COND_JMP(u, JGE, >=) 1590 COND_JMP(u, JLE, <=) 1591 COND_JMP(u, JSET, &) 1592 COND_JMP(s, JSGT, >) 1593 COND_JMP(s, JSLT, <) 1594 COND_JMP(s, JSGE, >=) 1595 COND_JMP(s, JSLE, <=) 1596 #undef COND_JMP 1597 /* STX and ST and LDX*/ 1598 #define LDST(SIZEOP, SIZE) \ 1599 STX_MEM_##SIZEOP: \ 1600 *(SIZE *)(unsigned long) (DST + insn->off) = SRC; \ 1601 CONT; \ 1602 ST_MEM_##SIZEOP: \ 1603 *(SIZE *)(unsigned long) (DST + insn->off) = IMM; \ 1604 CONT; \ 1605 LDX_MEM_##SIZEOP: \ 1606 DST = *(SIZE *)(unsigned long) (SRC + insn->off); \ 1607 CONT; 1608 1609 LDST(B, u8) 1610 LDST(H, u16) 1611 LDST(W, u32) 1612 LDST(DW, u64) 1613 #undef LDST 1614 #define LDX_PROBE(SIZEOP, SIZE) \ 1615 LDX_PROBE_MEM_##SIZEOP: \ 1616 bpf_probe_read_kernel(&DST, SIZE, (const void *)(long) (SRC + insn->off)); \ 1617 CONT; 1618 LDX_PROBE(B, 1) 1619 LDX_PROBE(H, 2) 1620 LDX_PROBE(W, 4) 1621 LDX_PROBE(DW, 8) 1622 #undef LDX_PROBE 1623 1624 STX_XADD_W: /* lock xadd *(u32 *)(dst_reg + off16) += src_reg */ 1625 atomic_add((u32) SRC, (atomic_t *)(unsigned long) 1626 (DST + insn->off)); 1627 CONT; 1628 STX_XADD_DW: /* lock xadd *(u64 *)(dst_reg + off16) += src_reg */ 1629 atomic64_add((u64) SRC, (atomic64_t *)(unsigned long) 1630 (DST + insn->off)); 1631 CONT; 1632 1633 default_label: 1634 /* If we ever reach this, we have a bug somewhere. Die hard here 1635 * instead of just returning 0; we could be somewhere in a subprog, 1636 * so execution could continue otherwise which we do /not/ want. 1637 * 1638 * Note, verifier whitelists all opcodes in bpf_opcode_in_insntable(). 1639 */ 1640 pr_warn("BPF interpreter: unknown opcode %02x\n", insn->code); 1641 BUG_ON(1); 1642 return 0; 1643 } 1644 1645 #define PROG_NAME(stack_size) __bpf_prog_run##stack_size 1646 #define DEFINE_BPF_PROG_RUN(stack_size) \ 1647 static unsigned int PROG_NAME(stack_size)(const void *ctx, const struct bpf_insn *insn) \ 1648 { \ 1649 u64 stack[stack_size / sizeof(u64)]; \ 1650 u64 regs[MAX_BPF_EXT_REG]; \ 1651 \ 1652 FP = (u64) (unsigned long) &stack[ARRAY_SIZE(stack)]; \ 1653 ARG1 = (u64) (unsigned long) ctx; \ 1654 return ___bpf_prog_run(regs, insn, stack); \ 1655 } 1656 1657 #define PROG_NAME_ARGS(stack_size) __bpf_prog_run_args##stack_size 1658 #define DEFINE_BPF_PROG_RUN_ARGS(stack_size) \ 1659 static u64 PROG_NAME_ARGS(stack_size)(u64 r1, u64 r2, u64 r3, u64 r4, u64 r5, \ 1660 const struct bpf_insn *insn) \ 1661 { \ 1662 u64 stack[stack_size / sizeof(u64)]; \ 1663 u64 regs[MAX_BPF_EXT_REG]; \ 1664 \ 1665 FP = (u64) (unsigned long) &stack[ARRAY_SIZE(stack)]; \ 1666 BPF_R1 = r1; \ 1667 BPF_R2 = r2; \ 1668 BPF_R3 = r3; \ 1669 BPF_R4 = r4; \ 1670 BPF_R5 = r5; \ 1671 return ___bpf_prog_run(regs, insn, stack); \ 1672 } 1673 1674 #define EVAL1(FN, X) FN(X) 1675 #define EVAL2(FN, X, Y...) FN(X) EVAL1(FN, Y) 1676 #define EVAL3(FN, X, Y...) FN(X) EVAL2(FN, Y) 1677 #define EVAL4(FN, X, Y...) FN(X) EVAL3(FN, Y) 1678 #define EVAL5(FN, X, Y...) FN(X) EVAL4(FN, Y) 1679 #define EVAL6(FN, X, Y...) FN(X) EVAL5(FN, Y) 1680 1681 EVAL6(DEFINE_BPF_PROG_RUN, 32, 64, 96, 128, 160, 192); 1682 EVAL6(DEFINE_BPF_PROG_RUN, 224, 256, 288, 320, 352, 384); 1683 EVAL4(DEFINE_BPF_PROG_RUN, 416, 448, 480, 512); 1684 1685 EVAL6(DEFINE_BPF_PROG_RUN_ARGS, 32, 64, 96, 128, 160, 192); 1686 EVAL6(DEFINE_BPF_PROG_RUN_ARGS, 224, 256, 288, 320, 352, 384); 1687 EVAL4(DEFINE_BPF_PROG_RUN_ARGS, 416, 448, 480, 512); 1688 1689 #define PROG_NAME_LIST(stack_size) PROG_NAME(stack_size), 1690 1691 static unsigned int (*interpreters[])(const void *ctx, 1692 const struct bpf_insn *insn) = { 1693 EVAL6(PROG_NAME_LIST, 32, 64, 96, 128, 160, 192) 1694 EVAL6(PROG_NAME_LIST, 224, 256, 288, 320, 352, 384) 1695 EVAL4(PROG_NAME_LIST, 416, 448, 480, 512) 1696 }; 1697 #undef PROG_NAME_LIST 1698 #define PROG_NAME_LIST(stack_size) PROG_NAME_ARGS(stack_size), 1699 static u64 (*interpreters_args[])(u64 r1, u64 r2, u64 r3, u64 r4, u64 r5, 1700 const struct bpf_insn *insn) = { 1701 EVAL6(PROG_NAME_LIST, 32, 64, 96, 128, 160, 192) 1702 EVAL6(PROG_NAME_LIST, 224, 256, 288, 320, 352, 384) 1703 EVAL4(PROG_NAME_LIST, 416, 448, 480, 512) 1704 }; 1705 #undef PROG_NAME_LIST 1706 1707 void bpf_patch_call_args(struct bpf_insn *insn, u32 stack_depth) 1708 { 1709 stack_depth = max_t(u32, stack_depth, 1); 1710 insn->off = (s16) insn->imm; 1711 insn->imm = interpreters_args[(round_up(stack_depth, 32) / 32) - 1] - 1712 __bpf_call_base_args; 1713 insn->code = BPF_JMP | BPF_CALL_ARGS; 1714 } 1715 1716 #else 1717 static unsigned int __bpf_prog_ret0_warn(const void *ctx, 1718 const struct bpf_insn *insn) 1719 { 1720 /* If this handler ever gets executed, then BPF_JIT_ALWAYS_ON 1721 * is not working properly, so warn about it! 1722 */ 1723 WARN_ON_ONCE(1); 1724 return 0; 1725 } 1726 #endif 1727 1728 bool bpf_prog_array_compatible(struct bpf_array *array, 1729 const struct bpf_prog *fp) 1730 { 1731 if (fp->kprobe_override) 1732 return false; 1733 1734 if (!array->aux->type) { 1735 /* There's no owner yet where we could check for 1736 * compatibility. 1737 */ 1738 array->aux->type = fp->type; 1739 array->aux->jited = fp->jited; 1740 return true; 1741 } 1742 1743 return array->aux->type == fp->type && 1744 array->aux->jited == fp->jited; 1745 } 1746 1747 static int bpf_check_tail_call(const struct bpf_prog *fp) 1748 { 1749 struct bpf_prog_aux *aux = fp->aux; 1750 int i; 1751 1752 for (i = 0; i < aux->used_map_cnt; i++) { 1753 struct bpf_map *map = aux->used_maps[i]; 1754 struct bpf_array *array; 1755 1756 if (map->map_type != BPF_MAP_TYPE_PROG_ARRAY) 1757 continue; 1758 1759 array = container_of(map, struct bpf_array, map); 1760 if (!bpf_prog_array_compatible(array, fp)) 1761 return -EINVAL; 1762 } 1763 1764 return 0; 1765 } 1766 1767 static void bpf_prog_select_func(struct bpf_prog *fp) 1768 { 1769 #ifndef CONFIG_BPF_JIT_ALWAYS_ON 1770 u32 stack_depth = max_t(u32, fp->aux->stack_depth, 1); 1771 1772 fp->bpf_func = interpreters[(round_up(stack_depth, 32) / 32) - 1]; 1773 #else 1774 fp->bpf_func = __bpf_prog_ret0_warn; 1775 #endif 1776 } 1777 1778 /** 1779 * bpf_prog_select_runtime - select exec runtime for BPF program 1780 * @fp: bpf_prog populated with internal BPF program 1781 * @err: pointer to error variable 1782 * 1783 * Try to JIT eBPF program, if JIT is not available, use interpreter. 1784 * The BPF program will be executed via BPF_PROG_RUN() macro. 1785 */ 1786 struct bpf_prog *bpf_prog_select_runtime(struct bpf_prog *fp, int *err) 1787 { 1788 /* In case of BPF to BPF calls, verifier did all the prep 1789 * work with regards to JITing, etc. 1790 */ 1791 if (fp->bpf_func) 1792 goto finalize; 1793 1794 bpf_prog_select_func(fp); 1795 1796 /* eBPF JITs can rewrite the program in case constant 1797 * blinding is active. However, in case of error during 1798 * blinding, bpf_int_jit_compile() must always return a 1799 * valid program, which in this case would simply not 1800 * be JITed, but falls back to the interpreter. 1801 */ 1802 if (!bpf_prog_is_dev_bound(fp->aux)) { 1803 *err = bpf_prog_alloc_jited_linfo(fp); 1804 if (*err) 1805 return fp; 1806 1807 fp = bpf_int_jit_compile(fp); 1808 if (!fp->jited) { 1809 bpf_prog_free_jited_linfo(fp); 1810 #ifdef CONFIG_BPF_JIT_ALWAYS_ON 1811 *err = -ENOTSUPP; 1812 return fp; 1813 #endif 1814 } else { 1815 bpf_prog_free_unused_jited_linfo(fp); 1816 } 1817 } else { 1818 *err = bpf_prog_offload_compile(fp); 1819 if (*err) 1820 return fp; 1821 } 1822 1823 finalize: 1824 bpf_prog_lock_ro(fp); 1825 1826 /* The tail call compatibility check can only be done at 1827 * this late stage as we need to determine, if we deal 1828 * with JITed or non JITed program concatenations and not 1829 * all eBPF JITs might immediately support all features. 1830 */ 1831 *err = bpf_check_tail_call(fp); 1832 1833 return fp; 1834 } 1835 EXPORT_SYMBOL_GPL(bpf_prog_select_runtime); 1836 1837 static unsigned int __bpf_prog_ret1(const void *ctx, 1838 const struct bpf_insn *insn) 1839 { 1840 return 1; 1841 } 1842 1843 static struct bpf_prog_dummy { 1844 struct bpf_prog prog; 1845 } dummy_bpf_prog = { 1846 .prog = { 1847 .bpf_func = __bpf_prog_ret1, 1848 }, 1849 }; 1850 1851 /* to avoid allocating empty bpf_prog_array for cgroups that 1852 * don't have bpf program attached use one global 'empty_prog_array' 1853 * It will not be modified the caller of bpf_prog_array_alloc() 1854 * (since caller requested prog_cnt == 0) 1855 * that pointer should be 'freed' by bpf_prog_array_free() 1856 */ 1857 static struct { 1858 struct bpf_prog_array hdr; 1859 struct bpf_prog *null_prog; 1860 } empty_prog_array = { 1861 .null_prog = NULL, 1862 }; 1863 1864 struct bpf_prog_array *bpf_prog_array_alloc(u32 prog_cnt, gfp_t flags) 1865 { 1866 if (prog_cnt) 1867 return kzalloc(sizeof(struct bpf_prog_array) + 1868 sizeof(struct bpf_prog_array_item) * 1869 (prog_cnt + 1), 1870 flags); 1871 1872 return &empty_prog_array.hdr; 1873 } 1874 1875 void bpf_prog_array_free(struct bpf_prog_array *progs) 1876 { 1877 if (!progs || progs == &empty_prog_array.hdr) 1878 return; 1879 kfree_rcu(progs, rcu); 1880 } 1881 1882 int bpf_prog_array_length(struct bpf_prog_array *array) 1883 { 1884 struct bpf_prog_array_item *item; 1885 u32 cnt = 0; 1886 1887 for (item = array->items; item->prog; item++) 1888 if (item->prog != &dummy_bpf_prog.prog) 1889 cnt++; 1890 return cnt; 1891 } 1892 1893 bool bpf_prog_array_is_empty(struct bpf_prog_array *array) 1894 { 1895 struct bpf_prog_array_item *item; 1896 1897 for (item = array->items; item->prog; item++) 1898 if (item->prog != &dummy_bpf_prog.prog) 1899 return false; 1900 return true; 1901 } 1902 1903 static bool bpf_prog_array_copy_core(struct bpf_prog_array *array, 1904 u32 *prog_ids, 1905 u32 request_cnt) 1906 { 1907 struct bpf_prog_array_item *item; 1908 int i = 0; 1909 1910 for (item = array->items; item->prog; item++) { 1911 if (item->prog == &dummy_bpf_prog.prog) 1912 continue; 1913 prog_ids[i] = item->prog->aux->id; 1914 if (++i == request_cnt) { 1915 item++; 1916 break; 1917 } 1918 } 1919 1920 return !!(item->prog); 1921 } 1922 1923 int bpf_prog_array_copy_to_user(struct bpf_prog_array *array, 1924 __u32 __user *prog_ids, u32 cnt) 1925 { 1926 unsigned long err = 0; 1927 bool nospc; 1928 u32 *ids; 1929 1930 /* users of this function are doing: 1931 * cnt = bpf_prog_array_length(); 1932 * if (cnt > 0) 1933 * bpf_prog_array_copy_to_user(..., cnt); 1934 * so below kcalloc doesn't need extra cnt > 0 check. 1935 */ 1936 ids = kcalloc(cnt, sizeof(u32), GFP_USER | __GFP_NOWARN); 1937 if (!ids) 1938 return -ENOMEM; 1939 nospc = bpf_prog_array_copy_core(array, ids, cnt); 1940 err = copy_to_user(prog_ids, ids, cnt * sizeof(u32)); 1941 kfree(ids); 1942 if (err) 1943 return -EFAULT; 1944 if (nospc) 1945 return -ENOSPC; 1946 return 0; 1947 } 1948 1949 void bpf_prog_array_delete_safe(struct bpf_prog_array *array, 1950 struct bpf_prog *old_prog) 1951 { 1952 struct bpf_prog_array_item *item; 1953 1954 for (item = array->items; item->prog; item++) 1955 if (item->prog == old_prog) { 1956 WRITE_ONCE(item->prog, &dummy_bpf_prog.prog); 1957 break; 1958 } 1959 } 1960 1961 int bpf_prog_array_copy(struct bpf_prog_array *old_array, 1962 struct bpf_prog *exclude_prog, 1963 struct bpf_prog *include_prog, 1964 struct bpf_prog_array **new_array) 1965 { 1966 int new_prog_cnt, carry_prog_cnt = 0; 1967 struct bpf_prog_array_item *existing; 1968 struct bpf_prog_array *array; 1969 bool found_exclude = false; 1970 int new_prog_idx = 0; 1971 1972 /* Figure out how many existing progs we need to carry over to 1973 * the new array. 1974 */ 1975 if (old_array) { 1976 existing = old_array->items; 1977 for (; existing->prog; existing++) { 1978 if (existing->prog == exclude_prog) { 1979 found_exclude = true; 1980 continue; 1981 } 1982 if (existing->prog != &dummy_bpf_prog.prog) 1983 carry_prog_cnt++; 1984 if (existing->prog == include_prog) 1985 return -EEXIST; 1986 } 1987 } 1988 1989 if (exclude_prog && !found_exclude) 1990 return -ENOENT; 1991 1992 /* How many progs (not NULL) will be in the new array? */ 1993 new_prog_cnt = carry_prog_cnt; 1994 if (include_prog) 1995 new_prog_cnt += 1; 1996 1997 /* Do we have any prog (not NULL) in the new array? */ 1998 if (!new_prog_cnt) { 1999 *new_array = NULL; 2000 return 0; 2001 } 2002 2003 /* +1 as the end of prog_array is marked with NULL */ 2004 array = bpf_prog_array_alloc(new_prog_cnt + 1, GFP_KERNEL); 2005 if (!array) 2006 return -ENOMEM; 2007 2008 /* Fill in the new prog array */ 2009 if (carry_prog_cnt) { 2010 existing = old_array->items; 2011 for (; existing->prog; existing++) 2012 if (existing->prog != exclude_prog && 2013 existing->prog != &dummy_bpf_prog.prog) { 2014 array->items[new_prog_idx++].prog = 2015 existing->prog; 2016 } 2017 } 2018 if (include_prog) 2019 array->items[new_prog_idx++].prog = include_prog; 2020 array->items[new_prog_idx].prog = NULL; 2021 *new_array = array; 2022 return 0; 2023 } 2024 2025 int bpf_prog_array_copy_info(struct bpf_prog_array *array, 2026 u32 *prog_ids, u32 request_cnt, 2027 u32 *prog_cnt) 2028 { 2029 u32 cnt = 0; 2030 2031 if (array) 2032 cnt = bpf_prog_array_length(array); 2033 2034 *prog_cnt = cnt; 2035 2036 /* return early if user requested only program count or nothing to copy */ 2037 if (!request_cnt || !cnt) 2038 return 0; 2039 2040 /* this function is called under trace/bpf_trace.c: bpf_event_mutex */ 2041 return bpf_prog_array_copy_core(array, prog_ids, request_cnt) ? -ENOSPC 2042 : 0; 2043 } 2044 2045 static void bpf_free_cgroup_storage(struct bpf_prog_aux *aux) 2046 { 2047 enum bpf_cgroup_storage_type stype; 2048 2049 for_each_cgroup_storage_type(stype) { 2050 if (!aux->cgroup_storage[stype]) 2051 continue; 2052 bpf_cgroup_storage_release(aux, aux->cgroup_storage[stype]); 2053 } 2054 } 2055 2056 void __bpf_free_used_maps(struct bpf_prog_aux *aux, 2057 struct bpf_map **used_maps, u32 len) 2058 { 2059 struct bpf_map *map; 2060 u32 i; 2061 2062 bpf_free_cgroup_storage(aux); 2063 for (i = 0; i < len; i++) { 2064 map = used_maps[i]; 2065 if (map->ops->map_poke_untrack) 2066 map->ops->map_poke_untrack(map, aux); 2067 bpf_map_put(map); 2068 } 2069 } 2070 2071 static void bpf_free_used_maps(struct bpf_prog_aux *aux) 2072 { 2073 __bpf_free_used_maps(aux, aux->used_maps, aux->used_map_cnt); 2074 kfree(aux->used_maps); 2075 } 2076 2077 static void bpf_prog_free_deferred(struct work_struct *work) 2078 { 2079 struct bpf_prog_aux *aux; 2080 int i; 2081 2082 aux = container_of(work, struct bpf_prog_aux, work); 2083 bpf_free_used_maps(aux); 2084 if (bpf_prog_is_dev_bound(aux)) 2085 bpf_prog_offload_destroy(aux->prog); 2086 #ifdef CONFIG_PERF_EVENTS 2087 if (aux->prog->has_callchain_buf) 2088 put_callchain_buffers(); 2089 #endif 2090 bpf_trampoline_put(aux->trampoline); 2091 for (i = 0; i < aux->func_cnt; i++) 2092 bpf_jit_free(aux->func[i]); 2093 if (aux->func_cnt) { 2094 kfree(aux->func); 2095 bpf_prog_unlock_free(aux->prog); 2096 } else { 2097 bpf_jit_free(aux->prog); 2098 } 2099 } 2100 2101 /* Free internal BPF program */ 2102 void bpf_prog_free(struct bpf_prog *fp) 2103 { 2104 struct bpf_prog_aux *aux = fp->aux; 2105 2106 if (aux->linked_prog) 2107 bpf_prog_put(aux->linked_prog); 2108 INIT_WORK(&aux->work, bpf_prog_free_deferred); 2109 schedule_work(&aux->work); 2110 } 2111 EXPORT_SYMBOL_GPL(bpf_prog_free); 2112 2113 /* RNG for unpriviledged user space with separated state from prandom_u32(). */ 2114 static DEFINE_PER_CPU(struct rnd_state, bpf_user_rnd_state); 2115 2116 void bpf_user_rnd_init_once(void) 2117 { 2118 prandom_init_once(&bpf_user_rnd_state); 2119 } 2120 2121 BPF_CALL_0(bpf_user_rnd_u32) 2122 { 2123 /* Should someone ever have the rather unwise idea to use some 2124 * of the registers passed into this function, then note that 2125 * this function is called from native eBPF and classic-to-eBPF 2126 * transformations. Register assignments from both sides are 2127 * different, f.e. classic always sets fn(ctx, A, X) here. 2128 */ 2129 struct rnd_state *state; 2130 u32 res; 2131 2132 state = &get_cpu_var(bpf_user_rnd_state); 2133 res = prandom_u32_state(state); 2134 put_cpu_var(bpf_user_rnd_state); 2135 2136 return res; 2137 } 2138 2139 BPF_CALL_0(bpf_get_raw_cpu_id) 2140 { 2141 return raw_smp_processor_id(); 2142 } 2143 2144 /* Weak definitions of helper functions in case we don't have bpf syscall. */ 2145 const struct bpf_func_proto bpf_map_lookup_elem_proto __weak; 2146 const struct bpf_func_proto bpf_map_update_elem_proto __weak; 2147 const struct bpf_func_proto bpf_map_delete_elem_proto __weak; 2148 const struct bpf_func_proto bpf_map_push_elem_proto __weak; 2149 const struct bpf_func_proto bpf_map_pop_elem_proto __weak; 2150 const struct bpf_func_proto bpf_map_peek_elem_proto __weak; 2151 const struct bpf_func_proto bpf_spin_lock_proto __weak; 2152 const struct bpf_func_proto bpf_spin_unlock_proto __weak; 2153 const struct bpf_func_proto bpf_jiffies64_proto __weak; 2154 2155 const struct bpf_func_proto bpf_get_prandom_u32_proto __weak; 2156 const struct bpf_func_proto bpf_get_smp_processor_id_proto __weak; 2157 const struct bpf_func_proto bpf_get_numa_node_id_proto __weak; 2158 const struct bpf_func_proto bpf_ktime_get_ns_proto __weak; 2159 const struct bpf_func_proto bpf_ktime_get_boot_ns_proto __weak; 2160 2161 const struct bpf_func_proto bpf_get_current_pid_tgid_proto __weak; 2162 const struct bpf_func_proto bpf_get_current_uid_gid_proto __weak; 2163 const struct bpf_func_proto bpf_get_current_comm_proto __weak; 2164 const struct bpf_func_proto bpf_get_current_cgroup_id_proto __weak; 2165 const struct bpf_func_proto bpf_get_current_ancestor_cgroup_id_proto __weak; 2166 const struct bpf_func_proto bpf_get_local_storage_proto __weak; 2167 const struct bpf_func_proto bpf_get_ns_current_pid_tgid_proto __weak; 2168 2169 const struct bpf_func_proto * __weak bpf_get_trace_printk_proto(void) 2170 { 2171 return NULL; 2172 } 2173 2174 u64 __weak 2175 bpf_event_output(struct bpf_map *map, u64 flags, void *meta, u64 meta_size, 2176 void *ctx, u64 ctx_size, bpf_ctx_copy_t ctx_copy) 2177 { 2178 return -ENOTSUPP; 2179 } 2180 EXPORT_SYMBOL_GPL(bpf_event_output); 2181 2182 /* Always built-in helper functions. */ 2183 const struct bpf_func_proto bpf_tail_call_proto = { 2184 .func = NULL, 2185 .gpl_only = false, 2186 .ret_type = RET_VOID, 2187 .arg1_type = ARG_PTR_TO_CTX, 2188 .arg2_type = ARG_CONST_MAP_PTR, 2189 .arg3_type = ARG_ANYTHING, 2190 }; 2191 2192 /* Stub for JITs that only support cBPF. eBPF programs are interpreted. 2193 * It is encouraged to implement bpf_int_jit_compile() instead, so that 2194 * eBPF and implicitly also cBPF can get JITed! 2195 */ 2196 struct bpf_prog * __weak bpf_int_jit_compile(struct bpf_prog *prog) 2197 { 2198 return prog; 2199 } 2200 2201 /* Stub for JITs that support eBPF. All cBPF code gets transformed into 2202 * eBPF by the kernel and is later compiled by bpf_int_jit_compile(). 2203 */ 2204 void __weak bpf_jit_compile(struct bpf_prog *prog) 2205 { 2206 } 2207 2208 bool __weak bpf_helper_changes_pkt_data(void *func) 2209 { 2210 return false; 2211 } 2212 2213 /* Return TRUE if the JIT backend wants verifier to enable sub-register usage 2214 * analysis code and wants explicit zero extension inserted by verifier. 2215 * Otherwise, return FALSE. 2216 */ 2217 bool __weak bpf_jit_needs_zext(void) 2218 { 2219 return false; 2220 } 2221 2222 /* To execute LD_ABS/LD_IND instructions __bpf_prog_run() may call 2223 * skb_copy_bits(), so provide a weak definition of it for NET-less config. 2224 */ 2225 int __weak skb_copy_bits(const struct sk_buff *skb, int offset, void *to, 2226 int len) 2227 { 2228 return -EFAULT; 2229 } 2230 2231 int __weak bpf_arch_text_poke(void *ip, enum bpf_text_poke_type t, 2232 void *addr1, void *addr2) 2233 { 2234 return -ENOTSUPP; 2235 } 2236 2237 DEFINE_STATIC_KEY_FALSE(bpf_stats_enabled_key); 2238 EXPORT_SYMBOL(bpf_stats_enabled_key); 2239 2240 /* All definitions of tracepoints related to BPF. */ 2241 #define CREATE_TRACE_POINTS 2242 #include <linux/bpf_trace.h> 2243 2244 EXPORT_TRACEPOINT_SYMBOL_GPL(xdp_exception); 2245 EXPORT_TRACEPOINT_SYMBOL_GPL(xdp_bulk_tx); 2246