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