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