1 /* 2 * Linux Socket Filter - Kernel level socket filtering 3 * 4 * Based on the design of the Berkeley Packet Filter. The new 5 * internal format has been designed by PLUMgrid: 6 * 7 * Copyright (c) 2011 - 2014 PLUMgrid, http://plumgrid.com 8 * 9 * Authors: 10 * 11 * Jay Schulist <jschlst@samba.org> 12 * Alexei Starovoitov <ast@plumgrid.com> 13 * Daniel Borkmann <dborkman@redhat.com> 14 * 15 * This program is free software; you can redistribute it and/or 16 * modify it under the terms of the GNU General Public License 17 * as published by the Free Software Foundation; either version 18 * 2 of the License, or (at your option) any later version. 19 * 20 * Andi Kleen - Fix a few bad bugs and races. 21 * Kris Katterjohn - Added many additional checks in bpf_check_classic() 22 */ 23 24 #include <uapi/linux/btf.h> 25 #include <linux/filter.h> 26 #include <linux/skbuff.h> 27 #include <linux/vmalloc.h> 28 #include <linux/random.h> 29 #include <linux/moduleloader.h> 30 #include <linux/bpf.h> 31 #include <linux/btf.h> 32 #include <linux/frame.h> 33 #include <linux/rbtree_latch.h> 34 #include <linux/kallsyms.h> 35 #include <linux/rcupdate.h> 36 #include <linux/perf_event.h> 37 38 #include <asm/unaligned.h> 39 40 /* Registers */ 41 #define BPF_R0 regs[BPF_REG_0] 42 #define BPF_R1 regs[BPF_REG_1] 43 #define BPF_R2 regs[BPF_REG_2] 44 #define BPF_R3 regs[BPF_REG_3] 45 #define BPF_R4 regs[BPF_REG_4] 46 #define BPF_R5 regs[BPF_REG_5] 47 #define BPF_R6 regs[BPF_REG_6] 48 #define BPF_R7 regs[BPF_REG_7] 49 #define BPF_R8 regs[BPF_REG_8] 50 #define BPF_R9 regs[BPF_REG_9] 51 #define BPF_R10 regs[BPF_REG_10] 52 53 /* Named registers */ 54 #define DST regs[insn->dst_reg] 55 #define SRC regs[insn->src_reg] 56 #define FP regs[BPF_REG_FP] 57 #define ARG1 regs[BPF_REG_ARG1] 58 #define CTX regs[BPF_REG_CTX] 59 #define IMM insn->imm 60 61 /* No hurry in this branch 62 * 63 * Exported for the bpf jit load helper. 64 */ 65 void *bpf_internal_load_pointer_neg_helper(const struct sk_buff *skb, int k, unsigned int size) 66 { 67 u8 *ptr = NULL; 68 69 if (k >= SKF_NET_OFF) 70 ptr = skb_network_header(skb) + k - SKF_NET_OFF; 71 else if (k >= SKF_LL_OFF) 72 ptr = skb_mac_header(skb) + k - SKF_LL_OFF; 73 74 if (ptr >= skb->head && ptr + size <= skb_tail_pointer(skb)) 75 return ptr; 76 77 return NULL; 78 } 79 80 struct bpf_prog *bpf_prog_alloc(unsigned int size, gfp_t gfp_extra_flags) 81 { 82 gfp_t gfp_flags = GFP_KERNEL | __GFP_ZERO | gfp_extra_flags; 83 struct bpf_prog_aux *aux; 84 struct bpf_prog *fp; 85 86 size = round_up(size, PAGE_SIZE); 87 fp = __vmalloc(size, gfp_flags, PAGE_KERNEL); 88 if (fp == NULL) 89 return NULL; 90 91 aux = kzalloc(sizeof(*aux), GFP_KERNEL | gfp_extra_flags); 92 if (aux == NULL) { 93 vfree(fp); 94 return NULL; 95 } 96 97 fp->pages = size / PAGE_SIZE; 98 fp->aux = aux; 99 fp->aux->prog = fp; 100 fp->jit_requested = ebpf_jit_enabled(); 101 102 INIT_LIST_HEAD_RCU(&fp->aux->ksym_lnode); 103 104 return fp; 105 } 106 EXPORT_SYMBOL_GPL(bpf_prog_alloc); 107 108 int bpf_prog_alloc_jited_linfo(struct bpf_prog *prog) 109 { 110 if (!prog->aux->nr_linfo || !prog->jit_requested) 111 return 0; 112 113 prog->aux->jited_linfo = kcalloc(prog->aux->nr_linfo, 114 sizeof(*prog->aux->jited_linfo), 115 GFP_KERNEL | __GFP_NOWARN); 116 if (!prog->aux->jited_linfo) 117 return -ENOMEM; 118 119 return 0; 120 } 121 122 void bpf_prog_free_jited_linfo(struct bpf_prog *prog) 123 { 124 kfree(prog->aux->jited_linfo); 125 prog->aux->jited_linfo = NULL; 126 } 127 128 void bpf_prog_free_unused_jited_linfo(struct bpf_prog *prog) 129 { 130 if (prog->aux->jited_linfo && !prog->aux->jited_linfo[0]) 131 bpf_prog_free_jited_linfo(prog); 132 } 133 134 /* The jit engine is responsible to provide an array 135 * for insn_off to the jited_off mapping (insn_to_jit_off). 136 * 137 * The idx to this array is the insn_off. Hence, the insn_off 138 * here is relative to the prog itself instead of the main prog. 139 * This array has one entry for each xlated bpf insn. 140 * 141 * jited_off is the byte off to the last byte of the jited insn. 142 * 143 * Hence, with 144 * insn_start: 145 * The first bpf insn off of the prog. The insn off 146 * here is relative to the main prog. 147 * e.g. if prog is a subprog, insn_start > 0 148 * linfo_idx: 149 * The prog's idx to prog->aux->linfo and jited_linfo 150 * 151 * jited_linfo[linfo_idx] = prog->bpf_func 152 * 153 * For i > linfo_idx, 154 * 155 * jited_linfo[i] = prog->bpf_func + 156 * insn_to_jit_off[linfo[i].insn_off - insn_start - 1] 157 */ 158 void bpf_prog_fill_jited_linfo(struct bpf_prog *prog, 159 const u32 *insn_to_jit_off) 160 { 161 u32 linfo_idx, insn_start, insn_end, nr_linfo, i; 162 const struct bpf_line_info *linfo; 163 void **jited_linfo; 164 165 if (!prog->aux->jited_linfo) 166 /* Userspace did not provide linfo */ 167 return; 168 169 linfo_idx = prog->aux->linfo_idx; 170 linfo = &prog->aux->linfo[linfo_idx]; 171 insn_start = linfo[0].insn_off; 172 insn_end = insn_start + prog->len; 173 174 jited_linfo = &prog->aux->jited_linfo[linfo_idx]; 175 jited_linfo[0] = prog->bpf_func; 176 177 nr_linfo = prog->aux->nr_linfo - linfo_idx; 178 179 for (i = 1; i < nr_linfo && linfo[i].insn_off < insn_end; i++) 180 /* The verifier ensures that linfo[i].insn_off is 181 * strictly increasing 182 */ 183 jited_linfo[i] = prog->bpf_func + 184 insn_to_jit_off[linfo[i].insn_off - insn_start - 1]; 185 } 186 187 void bpf_prog_free_linfo(struct bpf_prog *prog) 188 { 189 bpf_prog_free_jited_linfo(prog); 190 kvfree(prog->aux->linfo); 191 } 192 193 struct bpf_prog *bpf_prog_realloc(struct bpf_prog *fp_old, unsigned int size, 194 gfp_t gfp_extra_flags) 195 { 196 gfp_t gfp_flags = GFP_KERNEL | __GFP_ZERO | gfp_extra_flags; 197 struct bpf_prog *fp; 198 u32 pages, delta; 199 int ret; 200 201 BUG_ON(fp_old == NULL); 202 203 size = round_up(size, PAGE_SIZE); 204 pages = size / PAGE_SIZE; 205 if (pages <= fp_old->pages) 206 return fp_old; 207 208 delta = pages - fp_old->pages; 209 ret = __bpf_prog_charge(fp_old->aux->user, delta); 210 if (ret) 211 return NULL; 212 213 fp = __vmalloc(size, gfp_flags, PAGE_KERNEL); 214 if (fp == NULL) { 215 __bpf_prog_uncharge(fp_old->aux->user, delta); 216 } else { 217 memcpy(fp, fp_old, fp_old->pages * PAGE_SIZE); 218 fp->pages = pages; 219 fp->aux->prog = fp; 220 221 /* We keep fp->aux from fp_old around in the new 222 * reallocated structure. 223 */ 224 fp_old->aux = NULL; 225 __bpf_prog_free(fp_old); 226 } 227 228 return fp; 229 } 230 231 void __bpf_prog_free(struct bpf_prog *fp) 232 { 233 kfree(fp->aux); 234 vfree(fp); 235 } 236 237 int bpf_prog_calc_tag(struct bpf_prog *fp) 238 { 239 const u32 bits_offset = SHA_MESSAGE_BYTES - sizeof(__be64); 240 u32 raw_size = bpf_prog_tag_scratch_size(fp); 241 u32 digest[SHA_DIGEST_WORDS]; 242 u32 ws[SHA_WORKSPACE_WORDS]; 243 u32 i, bsize, psize, blocks; 244 struct bpf_insn *dst; 245 bool was_ld_map; 246 u8 *raw, *todo; 247 __be32 *result; 248 __be64 *bits; 249 250 raw = vmalloc(raw_size); 251 if (!raw) 252 return -ENOMEM; 253 254 sha_init(digest); 255 memset(ws, 0, sizeof(ws)); 256 257 /* We need to take out the map fd for the digest calculation 258 * since they are unstable from user space side. 259 */ 260 dst = (void *)raw; 261 for (i = 0, was_ld_map = false; i < fp->len; i++) { 262 dst[i] = fp->insnsi[i]; 263 if (!was_ld_map && 264 dst[i].code == (BPF_LD | BPF_IMM | BPF_DW) && 265 dst[i].src_reg == BPF_PSEUDO_MAP_FD) { 266 was_ld_map = true; 267 dst[i].imm = 0; 268 } else if (was_ld_map && 269 dst[i].code == 0 && 270 dst[i].dst_reg == 0 && 271 dst[i].src_reg == 0 && 272 dst[i].off == 0) { 273 was_ld_map = false; 274 dst[i].imm = 0; 275 } else { 276 was_ld_map = false; 277 } 278 } 279 280 psize = bpf_prog_insn_size(fp); 281 memset(&raw[psize], 0, raw_size - psize); 282 raw[psize++] = 0x80; 283 284 bsize = round_up(psize, SHA_MESSAGE_BYTES); 285 blocks = bsize / SHA_MESSAGE_BYTES; 286 todo = raw; 287 if (bsize - psize >= sizeof(__be64)) { 288 bits = (__be64 *)(todo + bsize - sizeof(__be64)); 289 } else { 290 bits = (__be64 *)(todo + bsize + bits_offset); 291 blocks++; 292 } 293 *bits = cpu_to_be64((psize - 1) << 3); 294 295 while (blocks--) { 296 sha_transform(digest, todo, ws); 297 todo += SHA_MESSAGE_BYTES; 298 } 299 300 result = (__force __be32 *)digest; 301 for (i = 0; i < SHA_DIGEST_WORDS; i++) 302 result[i] = cpu_to_be32(digest[i]); 303 memcpy(fp->tag, result, sizeof(fp->tag)); 304 305 vfree(raw); 306 return 0; 307 } 308 309 static int bpf_adj_delta_to_imm(struct bpf_insn *insn, u32 pos, u32 delta, 310 u32 curr, const bool probe_pass) 311 { 312 const s64 imm_min = S32_MIN, imm_max = S32_MAX; 313 s64 imm = insn->imm; 314 315 if (curr < pos && curr + imm + 1 > pos) 316 imm += delta; 317 else if (curr > pos + delta && curr + imm + 1 <= pos + delta) 318 imm -= delta; 319 if (imm < imm_min || imm > imm_max) 320 return -ERANGE; 321 if (!probe_pass) 322 insn->imm = imm; 323 return 0; 324 } 325 326 static int bpf_adj_delta_to_off(struct bpf_insn *insn, u32 pos, u32 delta, 327 u32 curr, const bool probe_pass) 328 { 329 const s32 off_min = S16_MIN, off_max = S16_MAX; 330 s32 off = insn->off; 331 332 if (curr < pos && curr + off + 1 > pos) 333 off += delta; 334 else if (curr > pos + delta && curr + off + 1 <= pos + delta) 335 off -= delta; 336 if (off < off_min || off > off_max) 337 return -ERANGE; 338 if (!probe_pass) 339 insn->off = off; 340 return 0; 341 } 342 343 static int bpf_adj_branches(struct bpf_prog *prog, u32 pos, u32 delta, 344 const bool probe_pass) 345 { 346 u32 i, insn_cnt = prog->len + (probe_pass ? delta : 0); 347 struct bpf_insn *insn = prog->insnsi; 348 int ret = 0; 349 350 for (i = 0; i < insn_cnt; i++, insn++) { 351 u8 code; 352 353 /* In the probing pass we still operate on the original, 354 * unpatched image in order to check overflows before we 355 * do any other adjustments. Therefore skip the patchlet. 356 */ 357 if (probe_pass && i == pos) { 358 i += delta + 1; 359 insn++; 360 } 361 code = insn->code; 362 if (BPF_CLASS(code) != BPF_JMP || 363 BPF_OP(code) == BPF_EXIT) 364 continue; 365 /* Adjust offset of jmps if we cross patch boundaries. */ 366 if (BPF_OP(code) == BPF_CALL) { 367 if (insn->src_reg != BPF_PSEUDO_CALL) 368 continue; 369 ret = bpf_adj_delta_to_imm(insn, pos, delta, i, 370 probe_pass); 371 } else { 372 ret = bpf_adj_delta_to_off(insn, pos, delta, i, 373 probe_pass); 374 } 375 if (ret) 376 break; 377 } 378 379 return ret; 380 } 381 382 static void bpf_adj_linfo(struct bpf_prog *prog, u32 off, u32 delta) 383 { 384 struct bpf_line_info *linfo; 385 u32 i, nr_linfo; 386 387 nr_linfo = prog->aux->nr_linfo; 388 if (!nr_linfo || !delta) 389 return; 390 391 linfo = prog->aux->linfo; 392 393 for (i = 0; i < nr_linfo; i++) 394 if (off < linfo[i].insn_off) 395 break; 396 397 /* Push all off < linfo[i].insn_off by delta */ 398 for (; i < nr_linfo; i++) 399 linfo[i].insn_off += delta; 400 } 401 402 struct bpf_prog *bpf_patch_insn_single(struct bpf_prog *prog, u32 off, 403 const struct bpf_insn *patch, u32 len) 404 { 405 u32 insn_adj_cnt, insn_rest, insn_delta = len - 1; 406 const u32 cnt_max = S16_MAX; 407 struct bpf_prog *prog_adj; 408 409 /* Since our patchlet doesn't expand the image, we're done. */ 410 if (insn_delta == 0) { 411 memcpy(prog->insnsi + off, patch, sizeof(*patch)); 412 return prog; 413 } 414 415 insn_adj_cnt = prog->len + insn_delta; 416 417 /* Reject anything that would potentially let the insn->off 418 * target overflow when we have excessive program expansions. 419 * We need to probe here before we do any reallocation where 420 * we afterwards may not fail anymore. 421 */ 422 if (insn_adj_cnt > cnt_max && 423 bpf_adj_branches(prog, off, insn_delta, true)) 424 return NULL; 425 426 /* Several new instructions need to be inserted. Make room 427 * for them. Likely, there's no need for a new allocation as 428 * last page could have large enough tailroom. 429 */ 430 prog_adj = bpf_prog_realloc(prog, bpf_prog_size(insn_adj_cnt), 431 GFP_USER); 432 if (!prog_adj) 433 return NULL; 434 435 prog_adj->len = insn_adj_cnt; 436 437 /* Patching happens in 3 steps: 438 * 439 * 1) Move over tail of insnsi from next instruction onwards, 440 * so we can patch the single target insn with one or more 441 * new ones (patching is always from 1 to n insns, n > 0). 442 * 2) Inject new instructions at the target location. 443 * 3) Adjust branch offsets if necessary. 444 */ 445 insn_rest = insn_adj_cnt - off - len; 446 447 memmove(prog_adj->insnsi + off + len, prog_adj->insnsi + off + 1, 448 sizeof(*patch) * insn_rest); 449 memcpy(prog_adj->insnsi + off, patch, sizeof(*patch) * len); 450 451 /* We are guaranteed to not fail at this point, otherwise 452 * the ship has sailed to reverse to the original state. An 453 * overflow cannot happen at this point. 454 */ 455 BUG_ON(bpf_adj_branches(prog_adj, off, insn_delta, false)); 456 457 bpf_adj_linfo(prog_adj, off, insn_delta); 458 459 return prog_adj; 460 } 461 462 void bpf_prog_kallsyms_del_subprogs(struct bpf_prog *fp) 463 { 464 int i; 465 466 for (i = 0; i < fp->aux->func_cnt; i++) 467 bpf_prog_kallsyms_del(fp->aux->func[i]); 468 } 469 470 void bpf_prog_kallsyms_del_all(struct bpf_prog *fp) 471 { 472 bpf_prog_kallsyms_del_subprogs(fp); 473 bpf_prog_kallsyms_del(fp); 474 } 475 476 #ifdef CONFIG_BPF_JIT 477 # define BPF_JIT_LIMIT_DEFAULT (PAGE_SIZE * 40000) 478 479 /* All BPF JIT sysctl knobs here. */ 480 int bpf_jit_enable __read_mostly = IS_BUILTIN(CONFIG_BPF_JIT_ALWAYS_ON); 481 int bpf_jit_harden __read_mostly; 482 int bpf_jit_kallsyms __read_mostly; 483 int bpf_jit_limit __read_mostly = BPF_JIT_LIMIT_DEFAULT; 484 485 static __always_inline void 486 bpf_get_prog_addr_region(const struct bpf_prog *prog, 487 unsigned long *symbol_start, 488 unsigned long *symbol_end) 489 { 490 const struct bpf_binary_header *hdr = bpf_jit_binary_hdr(prog); 491 unsigned long addr = (unsigned long)hdr; 492 493 WARN_ON_ONCE(!bpf_prog_ebpf_jited(prog)); 494 495 *symbol_start = addr; 496 *symbol_end = addr + hdr->pages * PAGE_SIZE; 497 } 498 499 static void bpf_get_prog_name(const struct bpf_prog *prog, char *sym) 500 { 501 const char *end = sym + KSYM_NAME_LEN; 502 const struct btf_type *type; 503 const char *func_name; 504 505 BUILD_BUG_ON(sizeof("bpf_prog_") + 506 sizeof(prog->tag) * 2 + 507 /* name has been null terminated. 508 * We should need +1 for the '_' preceding 509 * the name. However, the null character 510 * is double counted between the name and the 511 * sizeof("bpf_prog_") above, so we omit 512 * the +1 here. 513 */ 514 sizeof(prog->aux->name) > KSYM_NAME_LEN); 515 516 sym += snprintf(sym, KSYM_NAME_LEN, "bpf_prog_"); 517 sym = bin2hex(sym, prog->tag, sizeof(prog->tag)); 518 519 /* prog->aux->name will be ignored if full btf name is available */ 520 if (prog->aux->func_info_cnt) { 521 type = btf_type_by_id(prog->aux->btf, 522 prog->aux->func_info[prog->aux->func_idx].type_id); 523 func_name = btf_name_by_offset(prog->aux->btf, type->name_off); 524 snprintf(sym, (size_t)(end - sym), "_%s", func_name); 525 return; 526 } 527 528 if (prog->aux->name[0]) 529 snprintf(sym, (size_t)(end - sym), "_%s", prog->aux->name); 530 else 531 *sym = 0; 532 } 533 534 static __always_inline unsigned long 535 bpf_get_prog_addr_start(struct latch_tree_node *n) 536 { 537 unsigned long symbol_start, symbol_end; 538 const struct bpf_prog_aux *aux; 539 540 aux = container_of(n, struct bpf_prog_aux, ksym_tnode); 541 bpf_get_prog_addr_region(aux->prog, &symbol_start, &symbol_end); 542 543 return symbol_start; 544 } 545 546 static __always_inline bool bpf_tree_less(struct latch_tree_node *a, 547 struct latch_tree_node *b) 548 { 549 return bpf_get_prog_addr_start(a) < bpf_get_prog_addr_start(b); 550 } 551 552 static __always_inline int bpf_tree_comp(void *key, struct latch_tree_node *n) 553 { 554 unsigned long val = (unsigned long)key; 555 unsigned long symbol_start, symbol_end; 556 const struct bpf_prog_aux *aux; 557 558 aux = container_of(n, struct bpf_prog_aux, ksym_tnode); 559 bpf_get_prog_addr_region(aux->prog, &symbol_start, &symbol_end); 560 561 if (val < symbol_start) 562 return -1; 563 if (val >= symbol_end) 564 return 1; 565 566 return 0; 567 } 568 569 static const struct latch_tree_ops bpf_tree_ops = { 570 .less = bpf_tree_less, 571 .comp = bpf_tree_comp, 572 }; 573 574 static DEFINE_SPINLOCK(bpf_lock); 575 static LIST_HEAD(bpf_kallsyms); 576 static struct latch_tree_root bpf_tree __cacheline_aligned; 577 578 static void bpf_prog_ksym_node_add(struct bpf_prog_aux *aux) 579 { 580 WARN_ON_ONCE(!list_empty(&aux->ksym_lnode)); 581 list_add_tail_rcu(&aux->ksym_lnode, &bpf_kallsyms); 582 latch_tree_insert(&aux->ksym_tnode, &bpf_tree, &bpf_tree_ops); 583 } 584 585 static void bpf_prog_ksym_node_del(struct bpf_prog_aux *aux) 586 { 587 if (list_empty(&aux->ksym_lnode)) 588 return; 589 590 latch_tree_erase(&aux->ksym_tnode, &bpf_tree, &bpf_tree_ops); 591 list_del_rcu(&aux->ksym_lnode); 592 } 593 594 static bool bpf_prog_kallsyms_candidate(const struct bpf_prog *fp) 595 { 596 return fp->jited && !bpf_prog_was_classic(fp); 597 } 598 599 static bool bpf_prog_kallsyms_verify_off(const struct bpf_prog *fp) 600 { 601 return list_empty(&fp->aux->ksym_lnode) || 602 fp->aux->ksym_lnode.prev == LIST_POISON2; 603 } 604 605 void bpf_prog_kallsyms_add(struct bpf_prog *fp) 606 { 607 if (!bpf_prog_kallsyms_candidate(fp) || 608 !capable(CAP_SYS_ADMIN)) 609 return; 610 611 spin_lock_bh(&bpf_lock); 612 bpf_prog_ksym_node_add(fp->aux); 613 spin_unlock_bh(&bpf_lock); 614 } 615 616 void bpf_prog_kallsyms_del(struct bpf_prog *fp) 617 { 618 if (!bpf_prog_kallsyms_candidate(fp)) 619 return; 620 621 spin_lock_bh(&bpf_lock); 622 bpf_prog_ksym_node_del(fp->aux); 623 spin_unlock_bh(&bpf_lock); 624 } 625 626 static struct bpf_prog *bpf_prog_kallsyms_find(unsigned long addr) 627 { 628 struct latch_tree_node *n; 629 630 if (!bpf_jit_kallsyms_enabled()) 631 return NULL; 632 633 n = latch_tree_find((void *)addr, &bpf_tree, &bpf_tree_ops); 634 return n ? 635 container_of(n, struct bpf_prog_aux, ksym_tnode)->prog : 636 NULL; 637 } 638 639 const char *__bpf_address_lookup(unsigned long addr, unsigned long *size, 640 unsigned long *off, char *sym) 641 { 642 unsigned long symbol_start, symbol_end; 643 struct bpf_prog *prog; 644 char *ret = NULL; 645 646 rcu_read_lock(); 647 prog = bpf_prog_kallsyms_find(addr); 648 if (prog) { 649 bpf_get_prog_addr_region(prog, &symbol_start, &symbol_end); 650 bpf_get_prog_name(prog, sym); 651 652 ret = sym; 653 if (size) 654 *size = symbol_end - symbol_start; 655 if (off) 656 *off = addr - symbol_start; 657 } 658 rcu_read_unlock(); 659 660 return ret; 661 } 662 663 bool is_bpf_text_address(unsigned long addr) 664 { 665 bool ret; 666 667 rcu_read_lock(); 668 ret = bpf_prog_kallsyms_find(addr) != NULL; 669 rcu_read_unlock(); 670 671 return ret; 672 } 673 674 int bpf_get_kallsym(unsigned int symnum, unsigned long *value, char *type, 675 char *sym) 676 { 677 struct bpf_prog_aux *aux; 678 unsigned int it = 0; 679 int ret = -ERANGE; 680 681 if (!bpf_jit_kallsyms_enabled()) 682 return ret; 683 684 rcu_read_lock(); 685 list_for_each_entry_rcu(aux, &bpf_kallsyms, ksym_lnode) { 686 if (it++ != symnum) 687 continue; 688 689 bpf_get_prog_name(aux->prog, sym); 690 691 *value = (unsigned long)aux->prog->bpf_func; 692 *type = BPF_SYM_ELF_TYPE; 693 694 ret = 0; 695 break; 696 } 697 rcu_read_unlock(); 698 699 return ret; 700 } 701 702 static atomic_long_t bpf_jit_current; 703 704 #if defined(MODULES_VADDR) 705 static int __init bpf_jit_charge_init(void) 706 { 707 /* Only used as heuristic here to derive limit. */ 708 bpf_jit_limit = min_t(u64, round_up((MODULES_END - MODULES_VADDR) >> 2, 709 PAGE_SIZE), INT_MAX); 710 return 0; 711 } 712 pure_initcall(bpf_jit_charge_init); 713 #endif 714 715 static int bpf_jit_charge_modmem(u32 pages) 716 { 717 if (atomic_long_add_return(pages, &bpf_jit_current) > 718 (bpf_jit_limit >> PAGE_SHIFT)) { 719 if (!capable(CAP_SYS_ADMIN)) { 720 atomic_long_sub(pages, &bpf_jit_current); 721 return -EPERM; 722 } 723 } 724 725 return 0; 726 } 727 728 static void bpf_jit_uncharge_modmem(u32 pages) 729 { 730 atomic_long_sub(pages, &bpf_jit_current); 731 } 732 733 void *__weak bpf_jit_alloc_exec(unsigned long size) 734 { 735 return module_alloc(size); 736 } 737 738 void __weak bpf_jit_free_exec(void *addr) 739 { 740 module_memfree(addr); 741 } 742 743 struct bpf_binary_header * 744 bpf_jit_binary_alloc(unsigned int proglen, u8 **image_ptr, 745 unsigned int alignment, 746 bpf_jit_fill_hole_t bpf_fill_ill_insns) 747 { 748 struct bpf_binary_header *hdr; 749 u32 size, hole, start, pages; 750 751 /* Most of BPF filters are really small, but if some of them 752 * fill a page, allow at least 128 extra bytes to insert a 753 * random section of illegal instructions. 754 */ 755 size = round_up(proglen + sizeof(*hdr) + 128, PAGE_SIZE); 756 pages = size / PAGE_SIZE; 757 758 if (bpf_jit_charge_modmem(pages)) 759 return NULL; 760 hdr = bpf_jit_alloc_exec(size); 761 if (!hdr) { 762 bpf_jit_uncharge_modmem(pages); 763 return NULL; 764 } 765 766 /* Fill space with illegal/arch-dep instructions. */ 767 bpf_fill_ill_insns(hdr, size); 768 769 hdr->pages = pages; 770 hole = min_t(unsigned int, size - (proglen + sizeof(*hdr)), 771 PAGE_SIZE - sizeof(*hdr)); 772 start = (get_random_int() % hole) & ~(alignment - 1); 773 774 /* Leave a random number of instructions before BPF code. */ 775 *image_ptr = &hdr->image[start]; 776 777 return hdr; 778 } 779 780 void bpf_jit_binary_free(struct bpf_binary_header *hdr) 781 { 782 u32 pages = hdr->pages; 783 784 bpf_jit_free_exec(hdr); 785 bpf_jit_uncharge_modmem(pages); 786 } 787 788 /* This symbol is only overridden by archs that have different 789 * requirements than the usual eBPF JITs, f.e. when they only 790 * implement cBPF JIT, do not set images read-only, etc. 791 */ 792 void __weak bpf_jit_free(struct bpf_prog *fp) 793 { 794 if (fp->jited) { 795 struct bpf_binary_header *hdr = bpf_jit_binary_hdr(fp); 796 797 bpf_jit_binary_unlock_ro(hdr); 798 bpf_jit_binary_free(hdr); 799 800 WARN_ON_ONCE(!bpf_prog_kallsyms_verify_off(fp)); 801 } 802 803 bpf_prog_unlock_free(fp); 804 } 805 806 int bpf_jit_get_func_addr(const struct bpf_prog *prog, 807 const struct bpf_insn *insn, bool extra_pass, 808 u64 *func_addr, bool *func_addr_fixed) 809 { 810 s16 off = insn->off; 811 s32 imm = insn->imm; 812 u8 *addr; 813 814 *func_addr_fixed = insn->src_reg != BPF_PSEUDO_CALL; 815 if (!*func_addr_fixed) { 816 /* Place-holder address till the last pass has collected 817 * all addresses for JITed subprograms in which case we 818 * can pick them up from prog->aux. 819 */ 820 if (!extra_pass) 821 addr = NULL; 822 else if (prog->aux->func && 823 off >= 0 && off < prog->aux->func_cnt) 824 addr = (u8 *)prog->aux->func[off]->bpf_func; 825 else 826 return -EINVAL; 827 } else { 828 /* Address of a BPF helper call. Since part of the core 829 * kernel, it's always at a fixed location. __bpf_call_base 830 * and the helper with imm relative to it are both in core 831 * kernel. 832 */ 833 addr = (u8 *)__bpf_call_base + imm; 834 } 835 836 *func_addr = (unsigned long)addr; 837 return 0; 838 } 839 840 static int bpf_jit_blind_insn(const struct bpf_insn *from, 841 const struct bpf_insn *aux, 842 struct bpf_insn *to_buff) 843 { 844 struct bpf_insn *to = to_buff; 845 u32 imm_rnd = get_random_int(); 846 s16 off; 847 848 BUILD_BUG_ON(BPF_REG_AX + 1 != MAX_BPF_JIT_REG); 849 BUILD_BUG_ON(MAX_BPF_REG + 1 != MAX_BPF_JIT_REG); 850 851 if (from->imm == 0 && 852 (from->code == (BPF_ALU | BPF_MOV | BPF_K) || 853 from->code == (BPF_ALU64 | BPF_MOV | BPF_K))) { 854 *to++ = BPF_ALU64_REG(BPF_XOR, from->dst_reg, from->dst_reg); 855 goto out; 856 } 857 858 switch (from->code) { 859 case BPF_ALU | BPF_ADD | BPF_K: 860 case BPF_ALU | BPF_SUB | BPF_K: 861 case BPF_ALU | BPF_AND | BPF_K: 862 case BPF_ALU | BPF_OR | BPF_K: 863 case BPF_ALU | BPF_XOR | BPF_K: 864 case BPF_ALU | BPF_MUL | BPF_K: 865 case BPF_ALU | BPF_MOV | BPF_K: 866 case BPF_ALU | BPF_DIV | BPF_K: 867 case BPF_ALU | BPF_MOD | BPF_K: 868 *to++ = BPF_ALU32_IMM(BPF_MOV, BPF_REG_AX, imm_rnd ^ from->imm); 869 *to++ = BPF_ALU32_IMM(BPF_XOR, BPF_REG_AX, imm_rnd); 870 *to++ = BPF_ALU32_REG(from->code, from->dst_reg, BPF_REG_AX); 871 break; 872 873 case BPF_ALU64 | BPF_ADD | BPF_K: 874 case BPF_ALU64 | BPF_SUB | BPF_K: 875 case BPF_ALU64 | BPF_AND | BPF_K: 876 case BPF_ALU64 | BPF_OR | BPF_K: 877 case BPF_ALU64 | BPF_XOR | BPF_K: 878 case BPF_ALU64 | BPF_MUL | BPF_K: 879 case BPF_ALU64 | BPF_MOV | BPF_K: 880 case BPF_ALU64 | BPF_DIV | BPF_K: 881 case BPF_ALU64 | BPF_MOD | BPF_K: 882 *to++ = BPF_ALU64_IMM(BPF_MOV, BPF_REG_AX, imm_rnd ^ from->imm); 883 *to++ = BPF_ALU64_IMM(BPF_XOR, BPF_REG_AX, imm_rnd); 884 *to++ = BPF_ALU64_REG(from->code, from->dst_reg, BPF_REG_AX); 885 break; 886 887 case BPF_JMP | BPF_JEQ | BPF_K: 888 case BPF_JMP | BPF_JNE | BPF_K: 889 case BPF_JMP | BPF_JGT | BPF_K: 890 case BPF_JMP | BPF_JLT | BPF_K: 891 case BPF_JMP | BPF_JGE | BPF_K: 892 case BPF_JMP | BPF_JLE | BPF_K: 893 case BPF_JMP | BPF_JSGT | BPF_K: 894 case BPF_JMP | BPF_JSLT | BPF_K: 895 case BPF_JMP | BPF_JSGE | BPF_K: 896 case BPF_JMP | BPF_JSLE | BPF_K: 897 case BPF_JMP | BPF_JSET | BPF_K: 898 /* Accommodate for extra offset in case of a backjump. */ 899 off = from->off; 900 if (off < 0) 901 off -= 2; 902 *to++ = BPF_ALU64_IMM(BPF_MOV, BPF_REG_AX, imm_rnd ^ from->imm); 903 *to++ = BPF_ALU64_IMM(BPF_XOR, BPF_REG_AX, imm_rnd); 904 *to++ = BPF_JMP_REG(from->code, from->dst_reg, BPF_REG_AX, off); 905 break; 906 907 case BPF_LD | BPF_IMM | BPF_DW: 908 *to++ = BPF_ALU64_IMM(BPF_MOV, BPF_REG_AX, imm_rnd ^ aux[1].imm); 909 *to++ = BPF_ALU64_IMM(BPF_XOR, BPF_REG_AX, imm_rnd); 910 *to++ = BPF_ALU64_IMM(BPF_LSH, BPF_REG_AX, 32); 911 *to++ = BPF_ALU64_REG(BPF_MOV, aux[0].dst_reg, BPF_REG_AX); 912 break; 913 case 0: /* Part 2 of BPF_LD | BPF_IMM | BPF_DW. */ 914 *to++ = BPF_ALU32_IMM(BPF_MOV, BPF_REG_AX, imm_rnd ^ aux[0].imm); 915 *to++ = BPF_ALU32_IMM(BPF_XOR, BPF_REG_AX, imm_rnd); 916 *to++ = BPF_ALU64_REG(BPF_OR, aux[0].dst_reg, BPF_REG_AX); 917 break; 918 919 case BPF_ST | BPF_MEM | BPF_DW: 920 case BPF_ST | BPF_MEM | BPF_W: 921 case BPF_ST | BPF_MEM | BPF_H: 922 case BPF_ST | BPF_MEM | BPF_B: 923 *to++ = BPF_ALU64_IMM(BPF_MOV, BPF_REG_AX, imm_rnd ^ from->imm); 924 *to++ = BPF_ALU64_IMM(BPF_XOR, BPF_REG_AX, imm_rnd); 925 *to++ = BPF_STX_MEM(from->code, from->dst_reg, BPF_REG_AX, from->off); 926 break; 927 } 928 out: 929 return to - to_buff; 930 } 931 932 static struct bpf_prog *bpf_prog_clone_create(struct bpf_prog *fp_other, 933 gfp_t gfp_extra_flags) 934 { 935 gfp_t gfp_flags = GFP_KERNEL | __GFP_ZERO | gfp_extra_flags; 936 struct bpf_prog *fp; 937 938 fp = __vmalloc(fp_other->pages * PAGE_SIZE, gfp_flags, PAGE_KERNEL); 939 if (fp != NULL) { 940 /* aux->prog still points to the fp_other one, so 941 * when promoting the clone to the real program, 942 * this still needs to be adapted. 943 */ 944 memcpy(fp, fp_other, fp_other->pages * PAGE_SIZE); 945 } 946 947 return fp; 948 } 949 950 static void bpf_prog_clone_free(struct bpf_prog *fp) 951 { 952 /* aux was stolen by the other clone, so we cannot free 953 * it from this path! It will be freed eventually by the 954 * other program on release. 955 * 956 * At this point, we don't need a deferred release since 957 * clone is guaranteed to not be locked. 958 */ 959 fp->aux = NULL; 960 __bpf_prog_free(fp); 961 } 962 963 void bpf_jit_prog_release_other(struct bpf_prog *fp, struct bpf_prog *fp_other) 964 { 965 /* We have to repoint aux->prog to self, as we don't 966 * know whether fp here is the clone or the original. 967 */ 968 fp->aux->prog = fp; 969 bpf_prog_clone_free(fp_other); 970 } 971 972 struct bpf_prog *bpf_jit_blind_constants(struct bpf_prog *prog) 973 { 974 struct bpf_insn insn_buff[16], aux[2]; 975 struct bpf_prog *clone, *tmp; 976 int insn_delta, insn_cnt; 977 struct bpf_insn *insn; 978 int i, rewritten; 979 980 if (!bpf_jit_blinding_enabled(prog) || prog->blinded) 981 return prog; 982 983 clone = bpf_prog_clone_create(prog, GFP_USER); 984 if (!clone) 985 return ERR_PTR(-ENOMEM); 986 987 insn_cnt = clone->len; 988 insn = clone->insnsi; 989 990 for (i = 0; i < insn_cnt; i++, insn++) { 991 /* We temporarily need to hold the original ld64 insn 992 * so that we can still access the first part in the 993 * second blinding run. 994 */ 995 if (insn[0].code == (BPF_LD | BPF_IMM | BPF_DW) && 996 insn[1].code == 0) 997 memcpy(aux, insn, sizeof(aux)); 998 999 rewritten = bpf_jit_blind_insn(insn, aux, insn_buff); 1000 if (!rewritten) 1001 continue; 1002 1003 tmp = bpf_patch_insn_single(clone, i, insn_buff, rewritten); 1004 if (!tmp) { 1005 /* Patching may have repointed aux->prog during 1006 * realloc from the original one, so we need to 1007 * fix it up here on error. 1008 */ 1009 bpf_jit_prog_release_other(prog, clone); 1010 return ERR_PTR(-ENOMEM); 1011 } 1012 1013 clone = tmp; 1014 insn_delta = rewritten - 1; 1015 1016 /* Walk new program and skip insns we just inserted. */ 1017 insn = clone->insnsi + i + insn_delta; 1018 insn_cnt += insn_delta; 1019 i += insn_delta; 1020 } 1021 1022 clone->blinded = 1; 1023 return clone; 1024 } 1025 #endif /* CONFIG_BPF_JIT */ 1026 1027 /* Base function for offset calculation. Needs to go into .text section, 1028 * therefore keeping it non-static as well; will also be used by JITs 1029 * anyway later on, so do not let the compiler omit it. This also needs 1030 * to go into kallsyms for correlation from e.g. bpftool, so naming 1031 * must not change. 1032 */ 1033 noinline u64 __bpf_call_base(u64 r1, u64 r2, u64 r3, u64 r4, u64 r5) 1034 { 1035 return 0; 1036 } 1037 EXPORT_SYMBOL_GPL(__bpf_call_base); 1038 1039 /* All UAPI available opcodes. */ 1040 #define BPF_INSN_MAP(INSN_2, INSN_3) \ 1041 /* 32 bit ALU operations. */ \ 1042 /* Register based. */ \ 1043 INSN_3(ALU, ADD, X), \ 1044 INSN_3(ALU, SUB, X), \ 1045 INSN_3(ALU, AND, X), \ 1046 INSN_3(ALU, OR, X), \ 1047 INSN_3(ALU, LSH, X), \ 1048 INSN_3(ALU, RSH, X), \ 1049 INSN_3(ALU, XOR, X), \ 1050 INSN_3(ALU, MUL, X), \ 1051 INSN_3(ALU, MOV, X), \ 1052 INSN_3(ALU, ARSH, X), \ 1053 INSN_3(ALU, DIV, X), \ 1054 INSN_3(ALU, MOD, X), \ 1055 INSN_2(ALU, NEG), \ 1056 INSN_3(ALU, END, TO_BE), \ 1057 INSN_3(ALU, END, TO_LE), \ 1058 /* Immediate based. */ \ 1059 INSN_3(ALU, ADD, K), \ 1060 INSN_3(ALU, SUB, K), \ 1061 INSN_3(ALU, AND, K), \ 1062 INSN_3(ALU, OR, K), \ 1063 INSN_3(ALU, LSH, K), \ 1064 INSN_3(ALU, RSH, K), \ 1065 INSN_3(ALU, XOR, K), \ 1066 INSN_3(ALU, MUL, K), \ 1067 INSN_3(ALU, MOV, K), \ 1068 INSN_3(ALU, ARSH, K), \ 1069 INSN_3(ALU, DIV, K), \ 1070 INSN_3(ALU, MOD, K), \ 1071 /* 64 bit ALU operations. */ \ 1072 /* Register based. */ \ 1073 INSN_3(ALU64, ADD, X), \ 1074 INSN_3(ALU64, SUB, X), \ 1075 INSN_3(ALU64, AND, X), \ 1076 INSN_3(ALU64, OR, X), \ 1077 INSN_3(ALU64, LSH, X), \ 1078 INSN_3(ALU64, RSH, X), \ 1079 INSN_3(ALU64, XOR, X), \ 1080 INSN_3(ALU64, MUL, X), \ 1081 INSN_3(ALU64, MOV, X), \ 1082 INSN_3(ALU64, ARSH, X), \ 1083 INSN_3(ALU64, DIV, X), \ 1084 INSN_3(ALU64, MOD, X), \ 1085 INSN_2(ALU64, NEG), \ 1086 /* Immediate based. */ \ 1087 INSN_3(ALU64, ADD, K), \ 1088 INSN_3(ALU64, SUB, K), \ 1089 INSN_3(ALU64, AND, K), \ 1090 INSN_3(ALU64, OR, K), \ 1091 INSN_3(ALU64, LSH, K), \ 1092 INSN_3(ALU64, RSH, K), \ 1093 INSN_3(ALU64, XOR, K), \ 1094 INSN_3(ALU64, MUL, K), \ 1095 INSN_3(ALU64, MOV, K), \ 1096 INSN_3(ALU64, ARSH, K), \ 1097 INSN_3(ALU64, DIV, K), \ 1098 INSN_3(ALU64, MOD, K), \ 1099 /* Call instruction. */ \ 1100 INSN_2(JMP, CALL), \ 1101 /* Exit instruction. */ \ 1102 INSN_2(JMP, EXIT), \ 1103 /* Jump instructions. */ \ 1104 /* Register based. */ \ 1105 INSN_3(JMP, JEQ, X), \ 1106 INSN_3(JMP, JNE, X), \ 1107 INSN_3(JMP, JGT, X), \ 1108 INSN_3(JMP, JLT, X), \ 1109 INSN_3(JMP, JGE, X), \ 1110 INSN_3(JMP, JLE, X), \ 1111 INSN_3(JMP, JSGT, X), \ 1112 INSN_3(JMP, JSLT, X), \ 1113 INSN_3(JMP, JSGE, X), \ 1114 INSN_3(JMP, JSLE, X), \ 1115 INSN_3(JMP, JSET, X), \ 1116 /* Immediate based. */ \ 1117 INSN_3(JMP, JEQ, K), \ 1118 INSN_3(JMP, JNE, K), \ 1119 INSN_3(JMP, JGT, K), \ 1120 INSN_3(JMP, JLT, K), \ 1121 INSN_3(JMP, JGE, K), \ 1122 INSN_3(JMP, JLE, K), \ 1123 INSN_3(JMP, JSGT, K), \ 1124 INSN_3(JMP, JSLT, K), \ 1125 INSN_3(JMP, JSGE, K), \ 1126 INSN_3(JMP, JSLE, K), \ 1127 INSN_3(JMP, JSET, K), \ 1128 INSN_2(JMP, JA), \ 1129 /* Store instructions. */ \ 1130 /* Register based. */ \ 1131 INSN_3(STX, MEM, B), \ 1132 INSN_3(STX, MEM, H), \ 1133 INSN_3(STX, MEM, W), \ 1134 INSN_3(STX, MEM, DW), \ 1135 INSN_3(STX, XADD, W), \ 1136 INSN_3(STX, XADD, DW), \ 1137 /* Immediate based. */ \ 1138 INSN_3(ST, MEM, B), \ 1139 INSN_3(ST, MEM, H), \ 1140 INSN_3(ST, MEM, W), \ 1141 INSN_3(ST, MEM, DW), \ 1142 /* Load instructions. */ \ 1143 /* Register based. */ \ 1144 INSN_3(LDX, MEM, B), \ 1145 INSN_3(LDX, MEM, H), \ 1146 INSN_3(LDX, MEM, W), \ 1147 INSN_3(LDX, MEM, DW), \ 1148 /* Immediate based. */ \ 1149 INSN_3(LD, IMM, DW) 1150 1151 bool bpf_opcode_in_insntable(u8 code) 1152 { 1153 #define BPF_INSN_2_TBL(x, y) [BPF_##x | BPF_##y] = true 1154 #define BPF_INSN_3_TBL(x, y, z) [BPF_##x | BPF_##y | BPF_##z] = true 1155 static const bool public_insntable[256] = { 1156 [0 ... 255] = false, 1157 /* Now overwrite non-defaults ... */ 1158 BPF_INSN_MAP(BPF_INSN_2_TBL, BPF_INSN_3_TBL), 1159 /* UAPI exposed, but rewritten opcodes. cBPF carry-over. */ 1160 [BPF_LD | BPF_ABS | BPF_B] = true, 1161 [BPF_LD | BPF_ABS | BPF_H] = true, 1162 [BPF_LD | BPF_ABS | BPF_W] = true, 1163 [BPF_LD | BPF_IND | BPF_B] = true, 1164 [BPF_LD | BPF_IND | BPF_H] = true, 1165 [BPF_LD | BPF_IND | BPF_W] = true, 1166 }; 1167 #undef BPF_INSN_3_TBL 1168 #undef BPF_INSN_2_TBL 1169 return public_insntable[code]; 1170 } 1171 1172 #ifndef CONFIG_BPF_JIT_ALWAYS_ON 1173 /** 1174 * __bpf_prog_run - run eBPF program on a given context 1175 * @ctx: is the data we are operating on 1176 * @insn: is the array of eBPF instructions 1177 * 1178 * Decode and execute eBPF instructions. 1179 */ 1180 static u64 ___bpf_prog_run(u64 *regs, const struct bpf_insn *insn, u64 *stack) 1181 { 1182 u64 tmp; 1183 #define BPF_INSN_2_LBL(x, y) [BPF_##x | BPF_##y] = &&x##_##y 1184 #define BPF_INSN_3_LBL(x, y, z) [BPF_##x | BPF_##y | BPF_##z] = &&x##_##y##_##z 1185 static const void *jumptable[256] = { 1186 [0 ... 255] = &&default_label, 1187 /* Now overwrite non-defaults ... */ 1188 BPF_INSN_MAP(BPF_INSN_2_LBL, BPF_INSN_3_LBL), 1189 /* Non-UAPI available opcodes. */ 1190 [BPF_JMP | BPF_CALL_ARGS] = &&JMP_CALL_ARGS, 1191 [BPF_JMP | BPF_TAIL_CALL] = &&JMP_TAIL_CALL, 1192 }; 1193 #undef BPF_INSN_3_LBL 1194 #undef BPF_INSN_2_LBL 1195 u32 tail_call_cnt = 0; 1196 1197 #define CONT ({ insn++; goto select_insn; }) 1198 #define CONT_JMP ({ insn++; goto select_insn; }) 1199 1200 select_insn: 1201 goto *jumptable[insn->code]; 1202 1203 /* ALU */ 1204 #define ALU(OPCODE, OP) \ 1205 ALU64_##OPCODE##_X: \ 1206 DST = DST OP SRC; \ 1207 CONT; \ 1208 ALU_##OPCODE##_X: \ 1209 DST = (u32) DST OP (u32) SRC; \ 1210 CONT; \ 1211 ALU64_##OPCODE##_K: \ 1212 DST = DST OP IMM; \ 1213 CONT; \ 1214 ALU_##OPCODE##_K: \ 1215 DST = (u32) DST OP (u32) IMM; \ 1216 CONT; 1217 1218 ALU(ADD, +) 1219 ALU(SUB, -) 1220 ALU(AND, &) 1221 ALU(OR, |) 1222 ALU(LSH, <<) 1223 ALU(RSH, >>) 1224 ALU(XOR, ^) 1225 ALU(MUL, *) 1226 #undef ALU 1227 ALU_NEG: 1228 DST = (u32) -DST; 1229 CONT; 1230 ALU64_NEG: 1231 DST = -DST; 1232 CONT; 1233 ALU_MOV_X: 1234 DST = (u32) SRC; 1235 CONT; 1236 ALU_MOV_K: 1237 DST = (u32) IMM; 1238 CONT; 1239 ALU64_MOV_X: 1240 DST = SRC; 1241 CONT; 1242 ALU64_MOV_K: 1243 DST = IMM; 1244 CONT; 1245 LD_IMM_DW: 1246 DST = (u64) (u32) insn[0].imm | ((u64) (u32) insn[1].imm) << 32; 1247 insn++; 1248 CONT; 1249 ALU_ARSH_X: 1250 DST = (u64) (u32) ((*(s32 *) &DST) >> SRC); 1251 CONT; 1252 ALU_ARSH_K: 1253 DST = (u64) (u32) ((*(s32 *) &DST) >> IMM); 1254 CONT; 1255 ALU64_ARSH_X: 1256 (*(s64 *) &DST) >>= SRC; 1257 CONT; 1258 ALU64_ARSH_K: 1259 (*(s64 *) &DST) >>= IMM; 1260 CONT; 1261 ALU64_MOD_X: 1262 div64_u64_rem(DST, SRC, &tmp); 1263 DST = tmp; 1264 CONT; 1265 ALU_MOD_X: 1266 tmp = (u32) DST; 1267 DST = do_div(tmp, (u32) SRC); 1268 CONT; 1269 ALU64_MOD_K: 1270 div64_u64_rem(DST, IMM, &tmp); 1271 DST = tmp; 1272 CONT; 1273 ALU_MOD_K: 1274 tmp = (u32) DST; 1275 DST = do_div(tmp, (u32) IMM); 1276 CONT; 1277 ALU64_DIV_X: 1278 DST = div64_u64(DST, SRC); 1279 CONT; 1280 ALU_DIV_X: 1281 tmp = (u32) DST; 1282 do_div(tmp, (u32) SRC); 1283 DST = (u32) tmp; 1284 CONT; 1285 ALU64_DIV_K: 1286 DST = div64_u64(DST, IMM); 1287 CONT; 1288 ALU_DIV_K: 1289 tmp = (u32) DST; 1290 do_div(tmp, (u32) IMM); 1291 DST = (u32) tmp; 1292 CONT; 1293 ALU_END_TO_BE: 1294 switch (IMM) { 1295 case 16: 1296 DST = (__force u16) cpu_to_be16(DST); 1297 break; 1298 case 32: 1299 DST = (__force u32) cpu_to_be32(DST); 1300 break; 1301 case 64: 1302 DST = (__force u64) cpu_to_be64(DST); 1303 break; 1304 } 1305 CONT; 1306 ALU_END_TO_LE: 1307 switch (IMM) { 1308 case 16: 1309 DST = (__force u16) cpu_to_le16(DST); 1310 break; 1311 case 32: 1312 DST = (__force u32) cpu_to_le32(DST); 1313 break; 1314 case 64: 1315 DST = (__force u64) cpu_to_le64(DST); 1316 break; 1317 } 1318 CONT; 1319 1320 /* CALL */ 1321 JMP_CALL: 1322 /* Function call scratches BPF_R1-BPF_R5 registers, 1323 * preserves BPF_R6-BPF_R9, and stores return value 1324 * into BPF_R0. 1325 */ 1326 BPF_R0 = (__bpf_call_base + insn->imm)(BPF_R1, BPF_R2, BPF_R3, 1327 BPF_R4, BPF_R5); 1328 CONT; 1329 1330 JMP_CALL_ARGS: 1331 BPF_R0 = (__bpf_call_base_args + insn->imm)(BPF_R1, BPF_R2, 1332 BPF_R3, BPF_R4, 1333 BPF_R5, 1334 insn + insn->off + 1); 1335 CONT; 1336 1337 JMP_TAIL_CALL: { 1338 struct bpf_map *map = (struct bpf_map *) (unsigned long) BPF_R2; 1339 struct bpf_array *array = container_of(map, struct bpf_array, map); 1340 struct bpf_prog *prog; 1341 u32 index = BPF_R3; 1342 1343 if (unlikely(index >= array->map.max_entries)) 1344 goto out; 1345 if (unlikely(tail_call_cnt > MAX_TAIL_CALL_CNT)) 1346 goto out; 1347 1348 tail_call_cnt++; 1349 1350 prog = READ_ONCE(array->ptrs[index]); 1351 if (!prog) 1352 goto out; 1353 1354 /* ARG1 at this point is guaranteed to point to CTX from 1355 * the verifier side due to the fact that the tail call is 1356 * handeled like a helper, that is, bpf_tail_call_proto, 1357 * where arg1_type is ARG_PTR_TO_CTX. 1358 */ 1359 insn = prog->insnsi; 1360 goto select_insn; 1361 out: 1362 CONT; 1363 } 1364 /* JMP */ 1365 JMP_JA: 1366 insn += insn->off; 1367 CONT; 1368 JMP_JEQ_X: 1369 if (DST == SRC) { 1370 insn += insn->off; 1371 CONT_JMP; 1372 } 1373 CONT; 1374 JMP_JEQ_K: 1375 if (DST == IMM) { 1376 insn += insn->off; 1377 CONT_JMP; 1378 } 1379 CONT; 1380 JMP_JNE_X: 1381 if (DST != SRC) { 1382 insn += insn->off; 1383 CONT_JMP; 1384 } 1385 CONT; 1386 JMP_JNE_K: 1387 if (DST != IMM) { 1388 insn += insn->off; 1389 CONT_JMP; 1390 } 1391 CONT; 1392 JMP_JGT_X: 1393 if (DST > SRC) { 1394 insn += insn->off; 1395 CONT_JMP; 1396 } 1397 CONT; 1398 JMP_JGT_K: 1399 if (DST > IMM) { 1400 insn += insn->off; 1401 CONT_JMP; 1402 } 1403 CONT; 1404 JMP_JLT_X: 1405 if (DST < SRC) { 1406 insn += insn->off; 1407 CONT_JMP; 1408 } 1409 CONT; 1410 JMP_JLT_K: 1411 if (DST < IMM) { 1412 insn += insn->off; 1413 CONT_JMP; 1414 } 1415 CONT; 1416 JMP_JGE_X: 1417 if (DST >= SRC) { 1418 insn += insn->off; 1419 CONT_JMP; 1420 } 1421 CONT; 1422 JMP_JGE_K: 1423 if (DST >= IMM) { 1424 insn += insn->off; 1425 CONT_JMP; 1426 } 1427 CONT; 1428 JMP_JLE_X: 1429 if (DST <= SRC) { 1430 insn += insn->off; 1431 CONT_JMP; 1432 } 1433 CONT; 1434 JMP_JLE_K: 1435 if (DST <= IMM) { 1436 insn += insn->off; 1437 CONT_JMP; 1438 } 1439 CONT; 1440 JMP_JSGT_X: 1441 if (((s64) DST) > ((s64) SRC)) { 1442 insn += insn->off; 1443 CONT_JMP; 1444 } 1445 CONT; 1446 JMP_JSGT_K: 1447 if (((s64) DST) > ((s64) IMM)) { 1448 insn += insn->off; 1449 CONT_JMP; 1450 } 1451 CONT; 1452 JMP_JSLT_X: 1453 if (((s64) DST) < ((s64) SRC)) { 1454 insn += insn->off; 1455 CONT_JMP; 1456 } 1457 CONT; 1458 JMP_JSLT_K: 1459 if (((s64) DST) < ((s64) IMM)) { 1460 insn += insn->off; 1461 CONT_JMP; 1462 } 1463 CONT; 1464 JMP_JSGE_X: 1465 if (((s64) DST) >= ((s64) SRC)) { 1466 insn += insn->off; 1467 CONT_JMP; 1468 } 1469 CONT; 1470 JMP_JSGE_K: 1471 if (((s64) DST) >= ((s64) IMM)) { 1472 insn += insn->off; 1473 CONT_JMP; 1474 } 1475 CONT; 1476 JMP_JSLE_X: 1477 if (((s64) DST) <= ((s64) SRC)) { 1478 insn += insn->off; 1479 CONT_JMP; 1480 } 1481 CONT; 1482 JMP_JSLE_K: 1483 if (((s64) DST) <= ((s64) IMM)) { 1484 insn += insn->off; 1485 CONT_JMP; 1486 } 1487 CONT; 1488 JMP_JSET_X: 1489 if (DST & SRC) { 1490 insn += insn->off; 1491 CONT_JMP; 1492 } 1493 CONT; 1494 JMP_JSET_K: 1495 if (DST & IMM) { 1496 insn += insn->off; 1497 CONT_JMP; 1498 } 1499 CONT; 1500 JMP_EXIT: 1501 return BPF_R0; 1502 1503 /* STX and ST and LDX*/ 1504 #define LDST(SIZEOP, SIZE) \ 1505 STX_MEM_##SIZEOP: \ 1506 *(SIZE *)(unsigned long) (DST + insn->off) = SRC; \ 1507 CONT; \ 1508 ST_MEM_##SIZEOP: \ 1509 *(SIZE *)(unsigned long) (DST + insn->off) = IMM; \ 1510 CONT; \ 1511 LDX_MEM_##SIZEOP: \ 1512 DST = *(SIZE *)(unsigned long) (SRC + insn->off); \ 1513 CONT; 1514 1515 LDST(B, u8) 1516 LDST(H, u16) 1517 LDST(W, u32) 1518 LDST(DW, u64) 1519 #undef LDST 1520 STX_XADD_W: /* lock xadd *(u32 *)(dst_reg + off16) += src_reg */ 1521 atomic_add((u32) SRC, (atomic_t *)(unsigned long) 1522 (DST + insn->off)); 1523 CONT; 1524 STX_XADD_DW: /* lock xadd *(u64 *)(dst_reg + off16) += src_reg */ 1525 atomic64_add((u64) SRC, (atomic64_t *)(unsigned long) 1526 (DST + insn->off)); 1527 CONT; 1528 1529 default_label: 1530 /* If we ever reach this, we have a bug somewhere. Die hard here 1531 * instead of just returning 0; we could be somewhere in a subprog, 1532 * so execution could continue otherwise which we do /not/ want. 1533 * 1534 * Note, verifier whitelists all opcodes in bpf_opcode_in_insntable(). 1535 */ 1536 pr_warn("BPF interpreter: unknown opcode %02x\n", insn->code); 1537 BUG_ON(1); 1538 return 0; 1539 } 1540 STACK_FRAME_NON_STANDARD(___bpf_prog_run); /* jump table */ 1541 1542 #define PROG_NAME(stack_size) __bpf_prog_run##stack_size 1543 #define DEFINE_BPF_PROG_RUN(stack_size) \ 1544 static unsigned int PROG_NAME(stack_size)(const void *ctx, const struct bpf_insn *insn) \ 1545 { \ 1546 u64 stack[stack_size / sizeof(u64)]; \ 1547 u64 regs[MAX_BPF_REG]; \ 1548 \ 1549 FP = (u64) (unsigned long) &stack[ARRAY_SIZE(stack)]; \ 1550 ARG1 = (u64) (unsigned long) ctx; \ 1551 return ___bpf_prog_run(regs, insn, stack); \ 1552 } 1553 1554 #define PROG_NAME_ARGS(stack_size) __bpf_prog_run_args##stack_size 1555 #define DEFINE_BPF_PROG_RUN_ARGS(stack_size) \ 1556 static u64 PROG_NAME_ARGS(stack_size)(u64 r1, u64 r2, u64 r3, u64 r4, u64 r5, \ 1557 const struct bpf_insn *insn) \ 1558 { \ 1559 u64 stack[stack_size / sizeof(u64)]; \ 1560 u64 regs[MAX_BPF_REG]; \ 1561 \ 1562 FP = (u64) (unsigned long) &stack[ARRAY_SIZE(stack)]; \ 1563 BPF_R1 = r1; \ 1564 BPF_R2 = r2; \ 1565 BPF_R3 = r3; \ 1566 BPF_R4 = r4; \ 1567 BPF_R5 = r5; \ 1568 return ___bpf_prog_run(regs, insn, stack); \ 1569 } 1570 1571 #define EVAL1(FN, X) FN(X) 1572 #define EVAL2(FN, X, Y...) FN(X) EVAL1(FN, Y) 1573 #define EVAL3(FN, X, Y...) FN(X) EVAL2(FN, Y) 1574 #define EVAL4(FN, X, Y...) FN(X) EVAL3(FN, Y) 1575 #define EVAL5(FN, X, Y...) FN(X) EVAL4(FN, Y) 1576 #define EVAL6(FN, X, Y...) FN(X) EVAL5(FN, Y) 1577 1578 EVAL6(DEFINE_BPF_PROG_RUN, 32, 64, 96, 128, 160, 192); 1579 EVAL6(DEFINE_BPF_PROG_RUN, 224, 256, 288, 320, 352, 384); 1580 EVAL4(DEFINE_BPF_PROG_RUN, 416, 448, 480, 512); 1581 1582 EVAL6(DEFINE_BPF_PROG_RUN_ARGS, 32, 64, 96, 128, 160, 192); 1583 EVAL6(DEFINE_BPF_PROG_RUN_ARGS, 224, 256, 288, 320, 352, 384); 1584 EVAL4(DEFINE_BPF_PROG_RUN_ARGS, 416, 448, 480, 512); 1585 1586 #define PROG_NAME_LIST(stack_size) PROG_NAME(stack_size), 1587 1588 static unsigned int (*interpreters[])(const void *ctx, 1589 const struct bpf_insn *insn) = { 1590 EVAL6(PROG_NAME_LIST, 32, 64, 96, 128, 160, 192) 1591 EVAL6(PROG_NAME_LIST, 224, 256, 288, 320, 352, 384) 1592 EVAL4(PROG_NAME_LIST, 416, 448, 480, 512) 1593 }; 1594 #undef PROG_NAME_LIST 1595 #define PROG_NAME_LIST(stack_size) PROG_NAME_ARGS(stack_size), 1596 static u64 (*interpreters_args[])(u64 r1, u64 r2, u64 r3, u64 r4, u64 r5, 1597 const struct bpf_insn *insn) = { 1598 EVAL6(PROG_NAME_LIST, 32, 64, 96, 128, 160, 192) 1599 EVAL6(PROG_NAME_LIST, 224, 256, 288, 320, 352, 384) 1600 EVAL4(PROG_NAME_LIST, 416, 448, 480, 512) 1601 }; 1602 #undef PROG_NAME_LIST 1603 1604 void bpf_patch_call_args(struct bpf_insn *insn, u32 stack_depth) 1605 { 1606 stack_depth = max_t(u32, stack_depth, 1); 1607 insn->off = (s16) insn->imm; 1608 insn->imm = interpreters_args[(round_up(stack_depth, 32) / 32) - 1] - 1609 __bpf_call_base_args; 1610 insn->code = BPF_JMP | BPF_CALL_ARGS; 1611 } 1612 1613 #else 1614 static unsigned int __bpf_prog_ret0_warn(const void *ctx, 1615 const struct bpf_insn *insn) 1616 { 1617 /* If this handler ever gets executed, then BPF_JIT_ALWAYS_ON 1618 * is not working properly, so warn about it! 1619 */ 1620 WARN_ON_ONCE(1); 1621 return 0; 1622 } 1623 #endif 1624 1625 bool bpf_prog_array_compatible(struct bpf_array *array, 1626 const struct bpf_prog *fp) 1627 { 1628 if (fp->kprobe_override) 1629 return false; 1630 1631 if (!array->owner_prog_type) { 1632 /* There's no owner yet where we could check for 1633 * compatibility. 1634 */ 1635 array->owner_prog_type = fp->type; 1636 array->owner_jited = fp->jited; 1637 1638 return true; 1639 } 1640 1641 return array->owner_prog_type == fp->type && 1642 array->owner_jited == fp->jited; 1643 } 1644 1645 static int bpf_check_tail_call(const struct bpf_prog *fp) 1646 { 1647 struct bpf_prog_aux *aux = fp->aux; 1648 int i; 1649 1650 for (i = 0; i < aux->used_map_cnt; i++) { 1651 struct bpf_map *map = aux->used_maps[i]; 1652 struct bpf_array *array; 1653 1654 if (map->map_type != BPF_MAP_TYPE_PROG_ARRAY) 1655 continue; 1656 1657 array = container_of(map, struct bpf_array, map); 1658 if (!bpf_prog_array_compatible(array, fp)) 1659 return -EINVAL; 1660 } 1661 1662 return 0; 1663 } 1664 1665 static void bpf_prog_select_func(struct bpf_prog *fp) 1666 { 1667 #ifndef CONFIG_BPF_JIT_ALWAYS_ON 1668 u32 stack_depth = max_t(u32, fp->aux->stack_depth, 1); 1669 1670 fp->bpf_func = interpreters[(round_up(stack_depth, 32) / 32) - 1]; 1671 #else 1672 fp->bpf_func = __bpf_prog_ret0_warn; 1673 #endif 1674 } 1675 1676 /** 1677 * bpf_prog_select_runtime - select exec runtime for BPF program 1678 * @fp: bpf_prog populated with internal BPF program 1679 * @err: pointer to error variable 1680 * 1681 * Try to JIT eBPF program, if JIT is not available, use interpreter. 1682 * The BPF program will be executed via BPF_PROG_RUN() macro. 1683 */ 1684 struct bpf_prog *bpf_prog_select_runtime(struct bpf_prog *fp, int *err) 1685 { 1686 /* In case of BPF to BPF calls, verifier did all the prep 1687 * work with regards to JITing, etc. 1688 */ 1689 if (fp->bpf_func) 1690 goto finalize; 1691 1692 bpf_prog_select_func(fp); 1693 1694 /* eBPF JITs can rewrite the program in case constant 1695 * blinding is active. However, in case of error during 1696 * blinding, bpf_int_jit_compile() must always return a 1697 * valid program, which in this case would simply not 1698 * be JITed, but falls back to the interpreter. 1699 */ 1700 if (!bpf_prog_is_dev_bound(fp->aux)) { 1701 *err = bpf_prog_alloc_jited_linfo(fp); 1702 if (*err) 1703 return fp; 1704 1705 fp = bpf_int_jit_compile(fp); 1706 if (!fp->jited) { 1707 bpf_prog_free_jited_linfo(fp); 1708 #ifdef CONFIG_BPF_JIT_ALWAYS_ON 1709 *err = -ENOTSUPP; 1710 return fp; 1711 #endif 1712 } else { 1713 bpf_prog_free_unused_jited_linfo(fp); 1714 } 1715 } else { 1716 *err = bpf_prog_offload_compile(fp); 1717 if (*err) 1718 return fp; 1719 } 1720 1721 finalize: 1722 bpf_prog_lock_ro(fp); 1723 1724 /* The tail call compatibility check can only be done at 1725 * this late stage as we need to determine, if we deal 1726 * with JITed or non JITed program concatenations and not 1727 * all eBPF JITs might immediately support all features. 1728 */ 1729 *err = bpf_check_tail_call(fp); 1730 1731 return fp; 1732 } 1733 EXPORT_SYMBOL_GPL(bpf_prog_select_runtime); 1734 1735 static unsigned int __bpf_prog_ret1(const void *ctx, 1736 const struct bpf_insn *insn) 1737 { 1738 return 1; 1739 } 1740 1741 static struct bpf_prog_dummy { 1742 struct bpf_prog prog; 1743 } dummy_bpf_prog = { 1744 .prog = { 1745 .bpf_func = __bpf_prog_ret1, 1746 }, 1747 }; 1748 1749 /* to avoid allocating empty bpf_prog_array for cgroups that 1750 * don't have bpf program attached use one global 'empty_prog_array' 1751 * It will not be modified the caller of bpf_prog_array_alloc() 1752 * (since caller requested prog_cnt == 0) 1753 * that pointer should be 'freed' by bpf_prog_array_free() 1754 */ 1755 static struct { 1756 struct bpf_prog_array hdr; 1757 struct bpf_prog *null_prog; 1758 } empty_prog_array = { 1759 .null_prog = NULL, 1760 }; 1761 1762 struct bpf_prog_array *bpf_prog_array_alloc(u32 prog_cnt, gfp_t flags) 1763 { 1764 if (prog_cnt) 1765 return kzalloc(sizeof(struct bpf_prog_array) + 1766 sizeof(struct bpf_prog_array_item) * 1767 (prog_cnt + 1), 1768 flags); 1769 1770 return &empty_prog_array.hdr; 1771 } 1772 1773 void bpf_prog_array_free(struct bpf_prog_array __rcu *progs) 1774 { 1775 if (!progs || 1776 progs == (struct bpf_prog_array __rcu *)&empty_prog_array.hdr) 1777 return; 1778 kfree_rcu(progs, rcu); 1779 } 1780 1781 int bpf_prog_array_length(struct bpf_prog_array __rcu *array) 1782 { 1783 struct bpf_prog_array_item *item; 1784 u32 cnt = 0; 1785 1786 rcu_read_lock(); 1787 item = rcu_dereference(array)->items; 1788 for (; item->prog; item++) 1789 if (item->prog != &dummy_bpf_prog.prog) 1790 cnt++; 1791 rcu_read_unlock(); 1792 return cnt; 1793 } 1794 1795 1796 static bool bpf_prog_array_copy_core(struct bpf_prog_array __rcu *array, 1797 u32 *prog_ids, 1798 u32 request_cnt) 1799 { 1800 struct bpf_prog_array_item *item; 1801 int i = 0; 1802 1803 item = rcu_dereference_check(array, 1)->items; 1804 for (; item->prog; item++) { 1805 if (item->prog == &dummy_bpf_prog.prog) 1806 continue; 1807 prog_ids[i] = item->prog->aux->id; 1808 if (++i == request_cnt) { 1809 item++; 1810 break; 1811 } 1812 } 1813 1814 return !!(item->prog); 1815 } 1816 1817 int bpf_prog_array_copy_to_user(struct bpf_prog_array __rcu *array, 1818 __u32 __user *prog_ids, u32 cnt) 1819 { 1820 unsigned long err = 0; 1821 bool nospc; 1822 u32 *ids; 1823 1824 /* users of this function are doing: 1825 * cnt = bpf_prog_array_length(); 1826 * if (cnt > 0) 1827 * bpf_prog_array_copy_to_user(..., cnt); 1828 * so below kcalloc doesn't need extra cnt > 0 check, but 1829 * bpf_prog_array_length() releases rcu lock and 1830 * prog array could have been swapped with empty or larger array, 1831 * so always copy 'cnt' prog_ids to the user. 1832 * In a rare race the user will see zero prog_ids 1833 */ 1834 ids = kcalloc(cnt, sizeof(u32), GFP_USER | __GFP_NOWARN); 1835 if (!ids) 1836 return -ENOMEM; 1837 rcu_read_lock(); 1838 nospc = bpf_prog_array_copy_core(array, ids, cnt); 1839 rcu_read_unlock(); 1840 err = copy_to_user(prog_ids, ids, cnt * sizeof(u32)); 1841 kfree(ids); 1842 if (err) 1843 return -EFAULT; 1844 if (nospc) 1845 return -ENOSPC; 1846 return 0; 1847 } 1848 1849 void bpf_prog_array_delete_safe(struct bpf_prog_array __rcu *array, 1850 struct bpf_prog *old_prog) 1851 { 1852 struct bpf_prog_array_item *item = array->items; 1853 1854 for (; item->prog; item++) 1855 if (item->prog == old_prog) { 1856 WRITE_ONCE(item->prog, &dummy_bpf_prog.prog); 1857 break; 1858 } 1859 } 1860 1861 int bpf_prog_array_copy(struct bpf_prog_array __rcu *old_array, 1862 struct bpf_prog *exclude_prog, 1863 struct bpf_prog *include_prog, 1864 struct bpf_prog_array **new_array) 1865 { 1866 int new_prog_cnt, carry_prog_cnt = 0; 1867 struct bpf_prog_array_item *existing; 1868 struct bpf_prog_array *array; 1869 bool found_exclude = false; 1870 int new_prog_idx = 0; 1871 1872 /* Figure out how many existing progs we need to carry over to 1873 * the new array. 1874 */ 1875 if (old_array) { 1876 existing = old_array->items; 1877 for (; existing->prog; existing++) { 1878 if (existing->prog == exclude_prog) { 1879 found_exclude = true; 1880 continue; 1881 } 1882 if (existing->prog != &dummy_bpf_prog.prog) 1883 carry_prog_cnt++; 1884 if (existing->prog == include_prog) 1885 return -EEXIST; 1886 } 1887 } 1888 1889 if (exclude_prog && !found_exclude) 1890 return -ENOENT; 1891 1892 /* How many progs (not NULL) will be in the new array? */ 1893 new_prog_cnt = carry_prog_cnt; 1894 if (include_prog) 1895 new_prog_cnt += 1; 1896 1897 /* Do we have any prog (not NULL) in the new array? */ 1898 if (!new_prog_cnt) { 1899 *new_array = NULL; 1900 return 0; 1901 } 1902 1903 /* +1 as the end of prog_array is marked with NULL */ 1904 array = bpf_prog_array_alloc(new_prog_cnt + 1, GFP_KERNEL); 1905 if (!array) 1906 return -ENOMEM; 1907 1908 /* Fill in the new prog array */ 1909 if (carry_prog_cnt) { 1910 existing = old_array->items; 1911 for (; existing->prog; existing++) 1912 if (existing->prog != exclude_prog && 1913 existing->prog != &dummy_bpf_prog.prog) { 1914 array->items[new_prog_idx++].prog = 1915 existing->prog; 1916 } 1917 } 1918 if (include_prog) 1919 array->items[new_prog_idx++].prog = include_prog; 1920 array->items[new_prog_idx].prog = NULL; 1921 *new_array = array; 1922 return 0; 1923 } 1924 1925 int bpf_prog_array_copy_info(struct bpf_prog_array __rcu *array, 1926 u32 *prog_ids, u32 request_cnt, 1927 u32 *prog_cnt) 1928 { 1929 u32 cnt = 0; 1930 1931 if (array) 1932 cnt = bpf_prog_array_length(array); 1933 1934 *prog_cnt = cnt; 1935 1936 /* return early if user requested only program count or nothing to copy */ 1937 if (!request_cnt || !cnt) 1938 return 0; 1939 1940 /* this function is called under trace/bpf_trace.c: bpf_event_mutex */ 1941 return bpf_prog_array_copy_core(array, prog_ids, request_cnt) ? -ENOSPC 1942 : 0; 1943 } 1944 1945 static void bpf_prog_free_deferred(struct work_struct *work) 1946 { 1947 struct bpf_prog_aux *aux; 1948 int i; 1949 1950 aux = container_of(work, struct bpf_prog_aux, work); 1951 if (bpf_prog_is_dev_bound(aux)) 1952 bpf_prog_offload_destroy(aux->prog); 1953 #ifdef CONFIG_PERF_EVENTS 1954 if (aux->prog->has_callchain_buf) 1955 put_callchain_buffers(); 1956 #endif 1957 for (i = 0; i < aux->func_cnt; i++) 1958 bpf_jit_free(aux->func[i]); 1959 if (aux->func_cnt) { 1960 kfree(aux->func); 1961 bpf_prog_unlock_free(aux->prog); 1962 } else { 1963 bpf_jit_free(aux->prog); 1964 } 1965 } 1966 1967 /* Free internal BPF program */ 1968 void bpf_prog_free(struct bpf_prog *fp) 1969 { 1970 struct bpf_prog_aux *aux = fp->aux; 1971 1972 INIT_WORK(&aux->work, bpf_prog_free_deferred); 1973 schedule_work(&aux->work); 1974 } 1975 EXPORT_SYMBOL_GPL(bpf_prog_free); 1976 1977 /* RNG for unpriviledged user space with separated state from prandom_u32(). */ 1978 static DEFINE_PER_CPU(struct rnd_state, bpf_user_rnd_state); 1979 1980 void bpf_user_rnd_init_once(void) 1981 { 1982 prandom_init_once(&bpf_user_rnd_state); 1983 } 1984 1985 BPF_CALL_0(bpf_user_rnd_u32) 1986 { 1987 /* Should someone ever have the rather unwise idea to use some 1988 * of the registers passed into this function, then note that 1989 * this function is called from native eBPF and classic-to-eBPF 1990 * transformations. Register assignments from both sides are 1991 * different, f.e. classic always sets fn(ctx, A, X) here. 1992 */ 1993 struct rnd_state *state; 1994 u32 res; 1995 1996 state = &get_cpu_var(bpf_user_rnd_state); 1997 res = prandom_u32_state(state); 1998 put_cpu_var(bpf_user_rnd_state); 1999 2000 return res; 2001 } 2002 2003 /* Weak definitions of helper functions in case we don't have bpf syscall. */ 2004 const struct bpf_func_proto bpf_map_lookup_elem_proto __weak; 2005 const struct bpf_func_proto bpf_map_update_elem_proto __weak; 2006 const struct bpf_func_proto bpf_map_delete_elem_proto __weak; 2007 const struct bpf_func_proto bpf_map_push_elem_proto __weak; 2008 const struct bpf_func_proto bpf_map_pop_elem_proto __weak; 2009 const struct bpf_func_proto bpf_map_peek_elem_proto __weak; 2010 2011 const struct bpf_func_proto bpf_get_prandom_u32_proto __weak; 2012 const struct bpf_func_proto bpf_get_smp_processor_id_proto __weak; 2013 const struct bpf_func_proto bpf_get_numa_node_id_proto __weak; 2014 const struct bpf_func_proto bpf_ktime_get_ns_proto __weak; 2015 2016 const struct bpf_func_proto bpf_get_current_pid_tgid_proto __weak; 2017 const struct bpf_func_proto bpf_get_current_uid_gid_proto __weak; 2018 const struct bpf_func_proto bpf_get_current_comm_proto __weak; 2019 const struct bpf_func_proto bpf_get_current_cgroup_id_proto __weak; 2020 const struct bpf_func_proto bpf_get_local_storage_proto __weak; 2021 2022 const struct bpf_func_proto * __weak bpf_get_trace_printk_proto(void) 2023 { 2024 return NULL; 2025 } 2026 2027 u64 __weak 2028 bpf_event_output(struct bpf_map *map, u64 flags, void *meta, u64 meta_size, 2029 void *ctx, u64 ctx_size, bpf_ctx_copy_t ctx_copy) 2030 { 2031 return -ENOTSUPP; 2032 } 2033 EXPORT_SYMBOL_GPL(bpf_event_output); 2034 2035 /* Always built-in helper functions. */ 2036 const struct bpf_func_proto bpf_tail_call_proto = { 2037 .func = NULL, 2038 .gpl_only = false, 2039 .ret_type = RET_VOID, 2040 .arg1_type = ARG_PTR_TO_CTX, 2041 .arg2_type = ARG_CONST_MAP_PTR, 2042 .arg3_type = ARG_ANYTHING, 2043 }; 2044 2045 /* Stub for JITs that only support cBPF. eBPF programs are interpreted. 2046 * It is encouraged to implement bpf_int_jit_compile() instead, so that 2047 * eBPF and implicitly also cBPF can get JITed! 2048 */ 2049 struct bpf_prog * __weak bpf_int_jit_compile(struct bpf_prog *prog) 2050 { 2051 return prog; 2052 } 2053 2054 /* Stub for JITs that support eBPF. All cBPF code gets transformed into 2055 * eBPF by the kernel and is later compiled by bpf_int_jit_compile(). 2056 */ 2057 void __weak bpf_jit_compile(struct bpf_prog *prog) 2058 { 2059 } 2060 2061 bool __weak bpf_helper_changes_pkt_data(void *func) 2062 { 2063 return false; 2064 } 2065 2066 /* To execute LD_ABS/LD_IND instructions __bpf_prog_run() may call 2067 * skb_copy_bits(), so provide a weak definition of it for NET-less config. 2068 */ 2069 int __weak skb_copy_bits(const struct sk_buff *skb, int offset, void *to, 2070 int len) 2071 { 2072 return -EFAULT; 2073 } 2074 2075 /* All definitions of tracepoints related to BPF. */ 2076 #define CREATE_TRACE_POINTS 2077 #include <linux/bpf_trace.h> 2078 2079 EXPORT_TRACEPOINT_SYMBOL_GPL(xdp_exception); 2080