1 // SPDX-License-Identifier: GPL-2.0-or-later 2 /* 3 * Linux Socket Filter - Kernel level socket filtering 4 * 5 * Based on the design of the Berkeley Packet Filter. The new 6 * internal format has been designed by PLUMgrid: 7 * 8 * Copyright (c) 2011 - 2014 PLUMgrid, http://plumgrid.com 9 * 10 * Authors: 11 * 12 * Jay Schulist <jschlst@samba.org> 13 * Alexei Starovoitov <ast@plumgrid.com> 14 * Daniel Borkmann <dborkman@redhat.com> 15 * 16 * Andi Kleen - Fix a few bad bugs and races. 17 * Kris Katterjohn - Added many additional checks in bpf_check_classic() 18 */ 19 20 #include <uapi/linux/btf.h> 21 #include <crypto/sha1.h> 22 #include <linux/filter.h> 23 #include <linux/skbuff.h> 24 #include <linux/vmalloc.h> 25 #include <linux/prandom.h> 26 #include <linux/bpf.h> 27 #include <linux/btf.h> 28 #include <linux/hex.h> 29 #include <linux/objtool.h> 30 #include <linux/overflow.h> 31 #include <linux/rbtree_latch.h> 32 #include <linux/kallsyms.h> 33 #include <linux/rcupdate.h> 34 #include <linux/perf_event.h> 35 #include <linux/extable.h> 36 #include <linux/log2.h> 37 #include <linux/bpf_verifier.h> 38 #include <linux/nodemask.h> 39 #include <linux/nospec.h> 40 #include <linux/bpf_mem_alloc.h> 41 #include <linux/memcontrol.h> 42 #include <linux/execmem.h> 43 #include <crypto/sha2.h> 44 45 #include <asm/barrier.h> 46 #include <linux/unaligned.h> 47 48 /* Registers */ 49 #define BPF_R0 regs[BPF_REG_0] 50 #define BPF_R1 regs[BPF_REG_1] 51 #define BPF_R2 regs[BPF_REG_2] 52 #define BPF_R3 regs[BPF_REG_3] 53 #define BPF_R4 regs[BPF_REG_4] 54 #define BPF_R5 regs[BPF_REG_5] 55 #define BPF_R6 regs[BPF_REG_6] 56 #define BPF_R7 regs[BPF_REG_7] 57 #define BPF_R8 regs[BPF_REG_8] 58 #define BPF_R9 regs[BPF_REG_9] 59 #define BPF_R10 regs[BPF_REG_10] 60 61 /* Named registers */ 62 #define DST regs[insn->dst_reg] 63 #define SRC regs[insn->src_reg] 64 #define FP regs[BPF_REG_FP] 65 #define AX regs[BPF_REG_AX] 66 #define ARG1 regs[BPF_REG_ARG1] 67 #define CTX regs[BPF_REG_CTX] 68 #define OFF insn->off 69 #define IMM insn->imm 70 71 struct bpf_mem_alloc bpf_global_ma; 72 bool bpf_global_ma_set; 73 74 /* No hurry in this branch 75 * 76 * Exported for the bpf jit load helper. 77 */ 78 void *bpf_internal_load_pointer_neg_helper(const struct sk_buff *skb, int k, unsigned int size) 79 { 80 u8 *ptr = NULL; 81 82 if (k >= SKF_NET_OFF) { 83 ptr = skb_network_header(skb) + k - SKF_NET_OFF; 84 } else if (k >= SKF_LL_OFF) { 85 if (unlikely(!skb_mac_header_was_set(skb))) 86 return NULL; 87 ptr = skb_mac_header(skb) + k - SKF_LL_OFF; 88 } 89 if (ptr >= skb->head && ptr + size <= skb_tail_pointer(skb)) 90 return ptr; 91 92 return NULL; 93 } 94 95 /* tell bpf programs that include vmlinux.h kernel's PAGE_SIZE */ 96 enum page_size_enum { 97 __PAGE_SIZE = PAGE_SIZE 98 }; 99 100 struct bpf_prog *bpf_prog_alloc_no_stats(unsigned int size, gfp_t gfp_extra_flags) 101 { 102 gfp_t gfp_flags = bpf_memcg_flags(GFP_KERNEL | __GFP_ZERO | gfp_extra_flags); 103 struct bpf_prog_aux *aux; 104 struct bpf_prog *fp; 105 106 size = round_up(size, __PAGE_SIZE); 107 fp = __vmalloc(size, gfp_flags); 108 if (fp == NULL) 109 return NULL; 110 111 aux = kzalloc_obj(*aux, bpf_memcg_flags(GFP_KERNEL | gfp_extra_flags)); 112 if (aux == NULL) { 113 vfree(fp); 114 return NULL; 115 } 116 fp->active = __alloc_percpu_gfp(sizeof(u8[BPF_NR_CONTEXTS]), 4, 117 bpf_memcg_flags(GFP_KERNEL | gfp_extra_flags)); 118 if (!fp->active) { 119 vfree(fp); 120 kfree(aux); 121 return NULL; 122 } 123 124 fp->pages = size / PAGE_SIZE; 125 fp->aux = aux; 126 fp->aux->main_prog_aux = aux; 127 fp->aux->prog = fp; 128 fp->jit_requested = ebpf_jit_enabled(); 129 fp->blinding_requested = bpf_jit_blinding_enabled(fp); 130 #ifdef CONFIG_CGROUP_BPF 131 aux->cgroup_atype = CGROUP_BPF_ATTACH_TYPE_INVALID; 132 #endif 133 134 INIT_LIST_HEAD_RCU(&fp->aux->ksym.lnode); 135 #ifdef CONFIG_FINEIBT 136 INIT_LIST_HEAD_RCU(&fp->aux->ksym_prefix.lnode); 137 #endif 138 mutex_init(&fp->aux->used_maps_mutex); 139 mutex_init(&fp->aux->ext_mutex); 140 mutex_init(&fp->aux->dst_mutex); 141 mutex_init(&fp->aux->st_ops_assoc_mutex); 142 143 #ifdef CONFIG_BPF_SYSCALL 144 bpf_prog_stream_init(fp); 145 #endif 146 147 return fp; 148 } 149 150 struct bpf_prog *bpf_prog_alloc(unsigned int size, gfp_t gfp_extra_flags) 151 { 152 gfp_t gfp_flags = bpf_memcg_flags(GFP_KERNEL | __GFP_ZERO | gfp_extra_flags); 153 struct bpf_prog *prog; 154 int cpu; 155 156 prog = bpf_prog_alloc_no_stats(size, gfp_extra_flags); 157 if (!prog) 158 return NULL; 159 160 prog->stats = alloc_percpu_gfp(struct bpf_prog_stats, gfp_flags); 161 if (!prog->stats) { 162 free_percpu(prog->active); 163 kfree(prog->aux); 164 vfree(prog); 165 return NULL; 166 } 167 168 for_each_possible_cpu(cpu) { 169 struct bpf_prog_stats *pstats; 170 171 pstats = per_cpu_ptr(prog->stats, cpu); 172 u64_stats_init(&pstats->syncp); 173 } 174 return prog; 175 } 176 EXPORT_SYMBOL_GPL(bpf_prog_alloc); 177 178 int bpf_prog_alloc_jited_linfo(struct bpf_prog *prog) 179 { 180 if (!prog->aux->nr_linfo || !prog->jit_requested) 181 return 0; 182 183 prog->aux->jited_linfo = kvzalloc_objs(*prog->aux->jited_linfo, 184 prog->aux->nr_linfo, 185 bpf_memcg_flags(GFP_KERNEL | __GFP_NOWARN)); 186 if (!prog->aux->jited_linfo) 187 return -ENOMEM; 188 189 return 0; 190 } 191 192 void bpf_prog_jit_attempt_done(struct bpf_prog *prog) 193 { 194 if (prog->aux->jited_linfo && 195 (!prog->jited || !prog->aux->jited_linfo[0])) { 196 kvfree(prog->aux->jited_linfo); 197 prog->aux->jited_linfo = NULL; 198 } 199 200 kfree(prog->aux->kfunc_tab); 201 prog->aux->kfunc_tab = NULL; 202 } 203 204 /* The jit engine is responsible to provide an array 205 * for insn_off to the jited_off mapping (insn_to_jit_off). 206 * 207 * The idx to this array is the insn_off. Hence, the insn_off 208 * here is relative to the prog itself instead of the main prog. 209 * This array has one entry for each xlated bpf insn. 210 * 211 * jited_off is the byte off to the end of the jited insn. 212 * 213 * Hence, with 214 * insn_start: 215 * The first bpf insn off of the prog. The insn off 216 * here is relative to the main prog. 217 * e.g. if prog is a subprog, insn_start > 0 218 * linfo_idx: 219 * The prog's idx to prog->aux->linfo and jited_linfo 220 * 221 * jited_linfo[linfo_idx] = prog->bpf_func 222 * 223 * For i > linfo_idx, 224 * 225 * jited_linfo[i] = prog->bpf_func + 226 * insn_to_jit_off[linfo[i].insn_off - insn_start - 1] 227 */ 228 void bpf_prog_fill_jited_linfo(struct bpf_prog *prog, 229 const u32 *insn_to_jit_off) 230 { 231 u32 linfo_idx, insn_start, insn_end, nr_linfo, i; 232 const struct bpf_line_info *linfo; 233 void **jited_linfo; 234 235 if (!prog->aux->jited_linfo || prog->aux->func_idx > prog->aux->func_cnt) 236 /* Userspace did not provide linfo */ 237 return; 238 239 linfo_idx = prog->aux->linfo_idx; 240 linfo = &prog->aux->linfo[linfo_idx]; 241 insn_start = linfo[0].insn_off; 242 insn_end = insn_start + prog->len; 243 244 jited_linfo = &prog->aux->jited_linfo[linfo_idx]; 245 jited_linfo[0] = prog->bpf_func; 246 247 nr_linfo = prog->aux->nr_linfo - linfo_idx; 248 249 for (i = 1; i < nr_linfo && linfo[i].insn_off < insn_end; i++) 250 /* The verifier ensures that linfo[i].insn_off is 251 * strictly increasing 252 */ 253 jited_linfo[i] = prog->bpf_func + 254 insn_to_jit_off[linfo[i].insn_off - insn_start - 1]; 255 } 256 257 struct bpf_prog *bpf_prog_realloc(struct bpf_prog *fp_old, unsigned int size, 258 gfp_t gfp_extra_flags) 259 { 260 gfp_t gfp_flags = bpf_memcg_flags(GFP_KERNEL | __GFP_ZERO | gfp_extra_flags); 261 struct bpf_prog *fp; 262 u32 pages; 263 264 size = round_up(size, PAGE_SIZE); 265 pages = size / PAGE_SIZE; 266 if (pages <= fp_old->pages) 267 return fp_old; 268 269 fp = __vmalloc(size, gfp_flags); 270 if (fp) { 271 memcpy(fp, fp_old, fp_old->pages * PAGE_SIZE); 272 fp->pages = pages; 273 fp->aux->prog = fp; 274 275 /* We keep fp->aux from fp_old around in the new 276 * reallocated structure. 277 */ 278 fp_old->aux = NULL; 279 fp_old->stats = NULL; 280 fp_old->active = NULL; 281 __bpf_prog_free(fp_old); 282 } 283 284 return fp; 285 } 286 287 void __bpf_prog_free(struct bpf_prog *fp) 288 { 289 if (fp->aux) { 290 mutex_destroy(&fp->aux->used_maps_mutex); 291 mutex_destroy(&fp->aux->dst_mutex); 292 mutex_destroy(&fp->aux->st_ops_assoc_mutex); 293 kfree(fp->aux->poke_tab); 294 kfree(fp->aux); 295 } 296 free_percpu(fp->stats); 297 free_percpu(fp->active); 298 vfree(fp); 299 } 300 301 int bpf_prog_calc_tag(struct bpf_prog *fp) 302 { 303 size_t size = bpf_prog_insn_size(fp); 304 struct bpf_insn *dst; 305 bool was_ld_map; 306 u32 i; 307 308 dst = vmalloc(size); 309 if (!dst) 310 return -ENOMEM; 311 312 /* We need to take out the map fd for the digest calculation 313 * since they are unstable from user space side. 314 */ 315 for (i = 0, was_ld_map = false; i < fp->len; i++) { 316 dst[i] = fp->insnsi[i]; 317 if (!was_ld_map && 318 dst[i].code == (BPF_LD | BPF_IMM | BPF_DW) && 319 (dst[i].src_reg == BPF_PSEUDO_MAP_FD || 320 dst[i].src_reg == BPF_PSEUDO_MAP_VALUE)) { 321 was_ld_map = true; 322 dst[i].imm = 0; 323 } else if (was_ld_map && 324 dst[i].code == 0 && 325 dst[i].dst_reg == 0 && 326 dst[i].src_reg == 0 && 327 dst[i].off == 0) { 328 was_ld_map = false; 329 dst[i].imm = 0; 330 } else { 331 was_ld_map = false; 332 } 333 } 334 sha256((u8 *)dst, size, fp->digest); 335 vfree(dst); 336 return 0; 337 } 338 339 static int bpf_adj_delta_to_imm(struct bpf_insn *insn, u32 pos, s32 end_old, 340 s32 end_new, s32 curr, const bool probe_pass) 341 { 342 const s64 imm_min = S32_MIN, imm_max = S32_MAX; 343 s32 delta = end_new - end_old; 344 s64 imm = insn->imm; 345 346 if (curr < pos && curr + imm + 1 >= end_old) 347 imm += delta; 348 else if (curr >= end_new && curr + imm + 1 < end_new) 349 imm -= delta; 350 if (imm < imm_min || imm > imm_max) 351 return -ERANGE; 352 if (!probe_pass) 353 insn->imm = imm; 354 return 0; 355 } 356 357 static int bpf_adj_delta_to_off(struct bpf_insn *insn, u32 pos, s32 end_old, 358 s32 end_new, s32 curr, const bool probe_pass) 359 { 360 s64 off_min, off_max, off; 361 s32 delta = end_new - end_old; 362 363 if (insn->code == (BPF_JMP32 | BPF_JA)) { 364 off = insn->imm; 365 off_min = S32_MIN; 366 off_max = S32_MAX; 367 } else { 368 off = insn->off; 369 off_min = S16_MIN; 370 off_max = S16_MAX; 371 } 372 373 if (curr < pos && curr + off + 1 >= end_old) 374 off += delta; 375 else if (curr >= end_new && curr + off + 1 < end_new) 376 off -= delta; 377 if (off < off_min || off > off_max) 378 return -ERANGE; 379 if (!probe_pass) { 380 if (insn->code == (BPF_JMP32 | BPF_JA)) 381 insn->imm = off; 382 else 383 insn->off = off; 384 } 385 return 0; 386 } 387 388 static int bpf_adj_branches(struct bpf_prog *prog, u32 pos, s32 end_old, 389 s32 end_new, const bool probe_pass) 390 { 391 u32 i, insn_cnt = prog->len + (probe_pass ? end_new - end_old : 0); 392 struct bpf_insn *insn = prog->insnsi; 393 int ret = 0; 394 395 for (i = 0; i < insn_cnt; i++, insn++) { 396 u8 code; 397 398 /* In the probing pass we still operate on the original, 399 * unpatched image in order to check overflows before we 400 * do any other adjustments. Therefore skip the patchlet. 401 */ 402 if (probe_pass && i == pos) { 403 i = end_new; 404 insn = prog->insnsi + end_old; 405 } 406 if (bpf_pseudo_func(insn)) { 407 ret = bpf_adj_delta_to_imm(insn, pos, end_old, 408 end_new, i, probe_pass); 409 if (ret) 410 return ret; 411 continue; 412 } 413 code = insn->code; 414 if ((BPF_CLASS(code) != BPF_JMP && 415 BPF_CLASS(code) != BPF_JMP32) || 416 BPF_OP(code) == BPF_EXIT) 417 continue; 418 /* Adjust offset of jmps if we cross patch boundaries. */ 419 if (BPF_OP(code) == BPF_CALL) { 420 if (insn->src_reg != BPF_PSEUDO_CALL) 421 continue; 422 ret = bpf_adj_delta_to_imm(insn, pos, end_old, 423 end_new, i, probe_pass); 424 } else { 425 ret = bpf_adj_delta_to_off(insn, pos, end_old, 426 end_new, i, probe_pass); 427 } 428 if (ret) 429 break; 430 } 431 432 return ret; 433 } 434 435 static void bpf_adj_linfo(struct bpf_prog *prog, u32 off, u32 delta) 436 { 437 struct bpf_line_info *linfo; 438 u32 i, nr_linfo; 439 440 nr_linfo = prog->aux->nr_linfo; 441 if (!nr_linfo || !delta) 442 return; 443 444 linfo = prog->aux->linfo; 445 446 for (i = 0; i < nr_linfo; i++) 447 if (off < linfo[i].insn_off) 448 break; 449 450 /* Push all off < linfo[i].insn_off by delta */ 451 for (; i < nr_linfo; i++) 452 linfo[i].insn_off += delta; 453 } 454 455 struct bpf_prog *bpf_patch_insn_single(struct bpf_prog *prog, u32 off, 456 const struct bpf_insn *patch, u32 len) 457 { 458 u32 insn_adj_cnt, insn_rest, insn_delta = len - 1; 459 const u32 cnt_max = S16_MAX; 460 struct bpf_prog *prog_adj; 461 int err; 462 463 /* Since our patchlet doesn't expand the image, we're done. */ 464 if (insn_delta == 0) { 465 memcpy(prog->insnsi + off, patch, sizeof(*patch)); 466 return prog; 467 } 468 469 insn_adj_cnt = prog->len + insn_delta; 470 471 /* Reject anything that would potentially let the insn->off 472 * target overflow when we have excessive program expansions. 473 * We need to probe here before we do any reallocation where 474 * we afterwards may not fail anymore. 475 */ 476 if (insn_adj_cnt > cnt_max && 477 (err = bpf_adj_branches(prog, off, off + 1, off + len, true))) 478 return ERR_PTR(err); 479 480 /* Several new instructions need to be inserted. Make room 481 * for them. Likely, there's no need for a new allocation as 482 * last page could have large enough tailroom. 483 */ 484 prog_adj = bpf_prog_realloc(prog, bpf_prog_size(insn_adj_cnt), 485 GFP_USER); 486 if (!prog_adj) 487 return ERR_PTR(-ENOMEM); 488 489 prog_adj->len = insn_adj_cnt; 490 491 /* Patching happens in 3 steps: 492 * 493 * 1) Move over tail of insnsi from next instruction onwards, 494 * so we can patch the single target insn with one or more 495 * new ones (patching is always from 1 to n insns, n > 0). 496 * 2) Inject new instructions at the target location. 497 * 3) Adjust branch offsets if necessary. 498 */ 499 insn_rest = insn_adj_cnt - off - len; 500 501 memmove(prog_adj->insnsi + off + len, prog_adj->insnsi + off + 1, 502 sizeof(*patch) * insn_rest); 503 memcpy(prog_adj->insnsi + off, patch, sizeof(*patch) * len); 504 505 /* We are guaranteed to not fail at this point, otherwise 506 * the ship has sailed to reverse to the original state. An 507 * overflow cannot happen at this point. 508 */ 509 BUG_ON(bpf_adj_branches(prog_adj, off, off + 1, off + len, false)); 510 511 bpf_adj_linfo(prog_adj, off, insn_delta); 512 513 return prog_adj; 514 } 515 516 int bpf_remove_insns(struct bpf_prog *prog, u32 off, u32 cnt) 517 { 518 int err; 519 520 /* Branch offsets can't overflow when program is shrinking, no need 521 * to call bpf_adj_branches(..., true) here 522 */ 523 memmove(prog->insnsi + off, prog->insnsi + off + cnt, 524 sizeof(struct bpf_insn) * (prog->len - off - cnt)); 525 prog->len -= cnt; 526 527 err = bpf_adj_branches(prog, off, off + cnt, off, false); 528 WARN_ON_ONCE(err); 529 return err; 530 } 531 532 static void bpf_prog_kallsyms_del_subprogs(struct bpf_prog *fp) 533 { 534 int i; 535 536 for (i = 0; i < fp->aux->real_func_cnt; i++) 537 bpf_prog_kallsyms_del(fp->aux->func[i]); 538 } 539 540 void bpf_prog_kallsyms_del_all(struct bpf_prog *fp) 541 { 542 bpf_prog_kallsyms_del_subprogs(fp); 543 bpf_prog_kallsyms_del(fp); 544 } 545 546 #ifdef CONFIG_BPF_JIT 547 /* All BPF JIT sysctl knobs here. */ 548 int bpf_jit_enable __read_mostly = IS_BUILTIN(CONFIG_BPF_JIT_DEFAULT_ON); 549 int bpf_jit_kallsyms __read_mostly = IS_BUILTIN(CONFIG_BPF_JIT_DEFAULT_ON); 550 int bpf_jit_harden __read_mostly; 551 long bpf_jit_limit __read_mostly; 552 long bpf_jit_limit_max __read_mostly; 553 554 static void 555 bpf_prog_ksym_set_addr(struct bpf_prog *prog) 556 { 557 WARN_ON_ONCE(!bpf_prog_ebpf_jited(prog)); 558 559 prog->aux->ksym.start = (unsigned long) prog->bpf_func; 560 prog->aux->ksym.end = prog->aux->ksym.start + prog->jited_len; 561 } 562 563 static void 564 bpf_prog_ksym_set_name(struct bpf_prog *prog) 565 { 566 char *sym = prog->aux->ksym.name; 567 const char *end = sym + KSYM_NAME_LEN; 568 const struct btf_type *type; 569 const char *func_name; 570 571 BUILD_BUG_ON(sizeof("bpf_prog_") + 572 sizeof(prog->tag) * 2 + 573 /* name has been null terminated. 574 * We should need +1 for the '_' preceding 575 * the name. However, the null character 576 * is double counted between the name and the 577 * sizeof("bpf_prog_") above, so we omit 578 * the +1 here. 579 */ 580 sizeof(prog->aux->name) > KSYM_NAME_LEN); 581 582 sym += snprintf(sym, KSYM_NAME_LEN, "bpf_prog_"); 583 sym = bin2hex(sym, prog->tag, sizeof(prog->tag)); 584 585 /* prog->aux->name will be ignored if full btf name is available */ 586 if (prog->aux->func_info_cnt && prog->aux->func_idx < prog->aux->func_info_cnt) { 587 type = btf_type_by_id(prog->aux->btf, 588 prog->aux->func_info[prog->aux->func_idx].type_id); 589 func_name = btf_name_by_offset(prog->aux->btf, type->name_off); 590 snprintf(sym, (size_t)(end - sym), "_%s", func_name); 591 return; 592 } 593 594 if (prog->aux->name[0]) 595 snprintf(sym, (size_t)(end - sym), "_%s", prog->aux->name); 596 else 597 *sym = 0; 598 } 599 600 static unsigned long bpf_get_ksym_start(struct latch_tree_node *n) 601 { 602 return container_of(n, struct bpf_ksym, tnode)->start; 603 } 604 605 static __always_inline bool bpf_tree_less(struct latch_tree_node *a, 606 struct latch_tree_node *b) 607 { 608 return bpf_get_ksym_start(a) < bpf_get_ksym_start(b); 609 } 610 611 static __always_inline int bpf_tree_comp(void *key, struct latch_tree_node *n) 612 { 613 unsigned long val = (unsigned long)key; 614 const struct bpf_ksym *ksym; 615 616 ksym = container_of(n, struct bpf_ksym, tnode); 617 618 if (val < ksym->start) 619 return -1; 620 /* Ensure that we detect return addresses as part of the program, when 621 * the final instruction is a call for a program part of the stack 622 * trace. Therefore, do val > ksym->end instead of val >= ksym->end. 623 */ 624 if (val > ksym->end) 625 return 1; 626 627 return 0; 628 } 629 630 static const struct latch_tree_ops bpf_tree_ops = { 631 .less = bpf_tree_less, 632 .comp = bpf_tree_comp, 633 }; 634 635 static DEFINE_SPINLOCK(bpf_lock); 636 static LIST_HEAD(bpf_kallsyms); 637 static struct latch_tree_root bpf_tree __cacheline_aligned; 638 639 void bpf_ksym_add(struct bpf_ksym *ksym) 640 { 641 spin_lock_bh(&bpf_lock); 642 WARN_ON_ONCE(!list_empty(&ksym->lnode)); 643 list_add_tail_rcu(&ksym->lnode, &bpf_kallsyms); 644 latch_tree_insert(&ksym->tnode, &bpf_tree, &bpf_tree_ops); 645 spin_unlock_bh(&bpf_lock); 646 } 647 648 static void __bpf_ksym_del(struct bpf_ksym *ksym) 649 { 650 if (list_empty(&ksym->lnode)) 651 return; 652 653 latch_tree_erase(&ksym->tnode, &bpf_tree, &bpf_tree_ops); 654 list_del_rcu(&ksym->lnode); 655 } 656 657 void bpf_ksym_del(struct bpf_ksym *ksym) 658 { 659 spin_lock_bh(&bpf_lock); 660 __bpf_ksym_del(ksym); 661 spin_unlock_bh(&bpf_lock); 662 } 663 664 static bool bpf_prog_kallsyms_candidate(const struct bpf_prog *fp) 665 { 666 return fp->jited && !bpf_prog_was_classic(fp); 667 } 668 669 void bpf_prog_kallsyms_add(struct bpf_prog *fp) 670 { 671 if (!bpf_prog_kallsyms_candidate(fp) || 672 !bpf_token_capable(fp->aux->token, CAP_BPF)) 673 return; 674 675 bpf_prog_ksym_set_addr(fp); 676 bpf_prog_ksym_set_name(fp); 677 fp->aux->ksym.prog = true; 678 679 bpf_ksym_add(&fp->aux->ksym); 680 681 #ifdef CONFIG_FINEIBT 682 /* 683 * When FineIBT, code in the __cfi_foo() symbols can get executed 684 * and hence unwinder needs help. 685 */ 686 if (cfi_mode != CFI_FINEIBT) 687 return; 688 689 snprintf(fp->aux->ksym_prefix.name, KSYM_NAME_LEN, 690 "__cfi_%s", fp->aux->ksym.name); 691 692 fp->aux->ksym_prefix.start = (unsigned long) fp->bpf_func - 16; 693 fp->aux->ksym_prefix.end = (unsigned long) fp->bpf_func; 694 695 bpf_ksym_add(&fp->aux->ksym_prefix); 696 #endif 697 } 698 699 void bpf_prog_kallsyms_del(struct bpf_prog *fp) 700 { 701 if (!bpf_prog_kallsyms_candidate(fp)) 702 return; 703 704 bpf_ksym_del(&fp->aux->ksym); 705 #ifdef CONFIG_FINEIBT 706 if (cfi_mode != CFI_FINEIBT) 707 return; 708 bpf_ksym_del(&fp->aux->ksym_prefix); 709 #endif 710 } 711 712 static struct bpf_ksym *bpf_ksym_find(unsigned long addr) 713 { 714 struct latch_tree_node *n; 715 716 n = latch_tree_find((void *)addr, &bpf_tree, &bpf_tree_ops); 717 return n ? container_of(n, struct bpf_ksym, tnode) : NULL; 718 } 719 720 int bpf_address_lookup(unsigned long addr, unsigned long *size, 721 unsigned long *off, char *sym) 722 { 723 struct bpf_ksym *ksym; 724 int ret = 0; 725 726 rcu_read_lock(); 727 ksym = bpf_ksym_find(addr); 728 if (ksym) { 729 unsigned long symbol_start = ksym->start; 730 unsigned long symbol_end = ksym->end; 731 732 ret = strscpy(sym, ksym->name, KSYM_NAME_LEN); 733 734 if (size) 735 *size = symbol_end - symbol_start; 736 if (off) 737 *off = addr - symbol_start; 738 } 739 rcu_read_unlock(); 740 741 return ret; 742 } 743 744 bool is_bpf_text_address(unsigned long addr) 745 { 746 bool ret; 747 748 rcu_read_lock(); 749 ret = bpf_ksym_find(addr) != NULL; 750 rcu_read_unlock(); 751 752 return ret; 753 } 754 755 struct bpf_prog *bpf_prog_ksym_find(unsigned long addr) 756 { 757 struct bpf_ksym *ksym; 758 759 WARN_ON_ONCE(!rcu_read_lock_held()); 760 ksym = bpf_ksym_find(addr); 761 762 return ksym && ksym->prog ? 763 container_of(ksym, struct bpf_prog_aux, ksym)->prog : 764 NULL; 765 } 766 767 bool bpf_has_frame_pointer(unsigned long ip) 768 { 769 struct bpf_ksym *ksym; 770 unsigned long offset; 771 772 guard(rcu)(); 773 774 ksym = bpf_ksym_find(ip); 775 if (!ksym || !ksym->fp_start || !ksym->fp_end) 776 return false; 777 778 offset = ip - ksym->start; 779 780 return offset >= ksym->fp_start && offset < ksym->fp_end; 781 } 782 783 const struct exception_table_entry *search_bpf_extables(unsigned long addr) 784 { 785 const struct exception_table_entry *e = NULL; 786 struct bpf_prog *prog; 787 788 rcu_read_lock(); 789 prog = bpf_prog_ksym_find(addr); 790 if (!prog) 791 goto out; 792 if (!prog->aux->num_exentries) 793 goto out; 794 795 e = search_extable(prog->aux->extable, prog->aux->num_exentries, addr); 796 out: 797 rcu_read_unlock(); 798 return e; 799 } 800 801 int bpf_get_kallsym(unsigned int symnum, unsigned long *value, char *type, 802 char *sym) 803 { 804 struct bpf_ksym *ksym; 805 unsigned int it = 0; 806 int ret = -ERANGE; 807 808 if (!bpf_jit_kallsyms_enabled()) 809 return ret; 810 811 rcu_read_lock(); 812 list_for_each_entry_rcu(ksym, &bpf_kallsyms, lnode) { 813 if (it++ != symnum) 814 continue; 815 816 strscpy(sym, ksym->name, KSYM_NAME_LEN); 817 818 *value = ksym->start; 819 *type = BPF_SYM_ELF_TYPE; 820 821 ret = 0; 822 break; 823 } 824 rcu_read_unlock(); 825 826 return ret; 827 } 828 829 int bpf_jit_add_poke_descriptor(struct bpf_prog *prog, 830 struct bpf_jit_poke_descriptor *poke) 831 { 832 struct bpf_jit_poke_descriptor *tab = prog->aux->poke_tab; 833 static const u32 poke_tab_max = 1024; 834 u32 slot = prog->aux->size_poke_tab; 835 u32 size = slot + 1; 836 837 if (size > poke_tab_max) 838 return -ENOSPC; 839 if (poke->tailcall_target || poke->tailcall_target_stable || 840 poke->tailcall_bypass || poke->adj_off || poke->bypass_addr) 841 return -EINVAL; 842 843 switch (poke->reason) { 844 case BPF_POKE_REASON_TAIL_CALL: 845 if (!poke->tail_call.map) 846 return -EINVAL; 847 break; 848 default: 849 return -EINVAL; 850 } 851 852 tab = krealloc_array(tab, size, sizeof(*poke), GFP_KERNEL); 853 if (!tab) 854 return -ENOMEM; 855 856 memcpy(&tab[slot], poke, sizeof(*poke)); 857 prog->aux->size_poke_tab = size; 858 prog->aux->poke_tab = tab; 859 860 return slot; 861 } 862 863 /* 864 * BPF program pack allocator. 865 * 866 * Most BPF programs are pretty small. Allocating a hole page for each 867 * program is sometime a waste. Many small bpf program also adds pressure 868 * to instruction TLB. To solve this issue, we introduce a BPF program pack 869 * allocator. The prog_pack allocator uses HPAGE_PMD_SIZE page (2MB on x86) 870 * to host BPF programs. 871 */ 872 #define BPF_PROG_CHUNK_SHIFT 6 873 #define BPF_PROG_CHUNK_SIZE (1 << BPF_PROG_CHUNK_SHIFT) 874 #define BPF_PROG_CHUNK_MASK (~(BPF_PROG_CHUNK_SIZE - 1)) 875 876 struct bpf_prog_pack { 877 struct list_head list; 878 void *ptr; 879 unsigned long bitmap[]; 880 }; 881 882 void bpf_jit_fill_hole_with_zero(void *area, unsigned int size) 883 { 884 memset(area, 0, size); 885 } 886 887 #define BPF_PROG_SIZE_TO_NBITS(size) (round_up(size, BPF_PROG_CHUNK_SIZE) / BPF_PROG_CHUNK_SIZE) 888 889 static DEFINE_MUTEX(pack_mutex); 890 static LIST_HEAD(pack_list); 891 892 /* PMD_SIZE is not available in some special config, e.g. ARCH=arm with 893 * CONFIG_MMU=n. Use PAGE_SIZE in these cases. 894 */ 895 #ifdef PMD_SIZE 896 /* PMD_SIZE is really big for some archs. It doesn't make sense to 897 * reserve too much memory in one allocation. Hardcode BPF_PROG_PACK_SIZE to 898 * 2MiB * num_possible_nodes(). On most architectures PMD_SIZE will be 899 * greater than or equal to 2MB. 900 */ 901 #define BPF_PROG_PACK_SIZE (SZ_2M * num_possible_nodes()) 902 #else 903 #define BPF_PROG_PACK_SIZE PAGE_SIZE 904 #endif 905 906 #define BPF_PROG_CHUNK_COUNT (BPF_PROG_PACK_SIZE / BPF_PROG_CHUNK_SIZE) 907 908 static struct bpf_prog_pack *alloc_new_pack(bpf_jit_fill_hole_t bpf_fill_ill_insns) 909 { 910 struct bpf_prog_pack *pack; 911 int err; 912 913 pack = kzalloc_flex(*pack, bitmap, BITS_TO_LONGS(BPF_PROG_CHUNK_COUNT)); 914 if (!pack) 915 return NULL; 916 pack->ptr = bpf_jit_alloc_exec(BPF_PROG_PACK_SIZE); 917 if (!pack->ptr) 918 goto out; 919 bpf_fill_ill_insns(pack->ptr, BPF_PROG_PACK_SIZE); 920 bitmap_zero(pack->bitmap, BPF_PROG_PACK_SIZE / BPF_PROG_CHUNK_SIZE); 921 922 set_vm_flush_reset_perms(pack->ptr); 923 err = set_memory_rox((unsigned long)pack->ptr, 924 BPF_PROG_PACK_SIZE / PAGE_SIZE); 925 if (err) 926 goto out; 927 list_add_tail(&pack->list, &pack_list); 928 return pack; 929 930 out: 931 bpf_jit_free_exec(pack->ptr); 932 kfree(pack); 933 return NULL; 934 } 935 936 void *bpf_prog_pack_alloc(u32 size, bpf_jit_fill_hole_t bpf_fill_ill_insns) 937 { 938 unsigned int nbits = BPF_PROG_SIZE_TO_NBITS(size); 939 struct bpf_prog_pack *pack; 940 unsigned long pos; 941 void *ptr = NULL; 942 943 mutex_lock(&pack_mutex); 944 if (size > BPF_PROG_PACK_SIZE) { 945 size = round_up(size, PAGE_SIZE); 946 ptr = bpf_jit_alloc_exec(size); 947 if (ptr) { 948 int err; 949 950 bpf_fill_ill_insns(ptr, size); 951 set_vm_flush_reset_perms(ptr); 952 err = set_memory_rox((unsigned long)ptr, 953 size / PAGE_SIZE); 954 if (err) { 955 bpf_jit_free_exec(ptr); 956 ptr = NULL; 957 } 958 } 959 goto out; 960 } 961 list_for_each_entry(pack, &pack_list, list) { 962 pos = bitmap_find_next_zero_area(pack->bitmap, BPF_PROG_CHUNK_COUNT, 0, 963 nbits, 0); 964 if (pos < BPF_PROG_CHUNK_COUNT) 965 goto found_free_area; 966 } 967 968 pack = alloc_new_pack(bpf_fill_ill_insns); 969 if (!pack) 970 goto out; 971 972 pos = 0; 973 974 found_free_area: 975 bitmap_set(pack->bitmap, pos, nbits); 976 ptr = (void *)(pack->ptr) + (pos << BPF_PROG_CHUNK_SHIFT); 977 978 out: 979 mutex_unlock(&pack_mutex); 980 return ptr; 981 } 982 983 void bpf_prog_pack_free(void *ptr, u32 size) 984 { 985 struct bpf_prog_pack *pack = NULL, *tmp; 986 unsigned int nbits; 987 unsigned long pos; 988 989 mutex_lock(&pack_mutex); 990 if (size > BPF_PROG_PACK_SIZE) { 991 bpf_jit_free_exec(ptr); 992 goto out; 993 } 994 995 list_for_each_entry(tmp, &pack_list, list) { 996 if (ptr >= tmp->ptr && (tmp->ptr + BPF_PROG_PACK_SIZE) > ptr) { 997 pack = tmp; 998 break; 999 } 1000 } 1001 1002 if (WARN_ONCE(!pack, "bpf_prog_pack bug\n")) 1003 goto out; 1004 1005 nbits = BPF_PROG_SIZE_TO_NBITS(size); 1006 pos = ((unsigned long)ptr - (unsigned long)pack->ptr) >> BPF_PROG_CHUNK_SHIFT; 1007 1008 WARN_ONCE(bpf_arch_text_invalidate(ptr, size), 1009 "bpf_prog_pack bug: missing bpf_arch_text_invalidate?\n"); 1010 1011 bitmap_clear(pack->bitmap, pos, nbits); 1012 if (bitmap_find_next_zero_area(pack->bitmap, BPF_PROG_CHUNK_COUNT, 0, 1013 BPF_PROG_CHUNK_COUNT, 0) == 0) { 1014 list_del(&pack->list); 1015 bpf_jit_free_exec(pack->ptr); 1016 kfree(pack); 1017 } 1018 out: 1019 mutex_unlock(&pack_mutex); 1020 } 1021 1022 static atomic_long_t bpf_jit_current; 1023 1024 /* Can be overridden by an arch's JIT compiler if it has a custom, 1025 * dedicated BPF backend memory area, or if neither of the two 1026 * below apply. 1027 */ 1028 u64 __weak bpf_jit_alloc_exec_limit(void) 1029 { 1030 #if defined(MODULES_VADDR) 1031 return MODULES_END - MODULES_VADDR; 1032 #else 1033 return VMALLOC_END - VMALLOC_START; 1034 #endif 1035 } 1036 1037 static int __init bpf_jit_charge_init(void) 1038 { 1039 /* Only used as heuristic here to derive limit. */ 1040 bpf_jit_limit_max = bpf_jit_alloc_exec_limit(); 1041 bpf_jit_limit = min_t(u64, round_up(bpf_jit_limit_max >> 1, 1042 PAGE_SIZE), LONG_MAX); 1043 return 0; 1044 } 1045 pure_initcall(bpf_jit_charge_init); 1046 1047 int bpf_jit_charge_modmem(u32 size) 1048 { 1049 if (atomic_long_add_return(size, &bpf_jit_current) > READ_ONCE(bpf_jit_limit)) { 1050 if (!bpf_capable()) { 1051 atomic_long_sub(size, &bpf_jit_current); 1052 return -EPERM; 1053 } 1054 } 1055 1056 return 0; 1057 } 1058 1059 void bpf_jit_uncharge_modmem(u32 size) 1060 { 1061 atomic_long_sub(size, &bpf_jit_current); 1062 } 1063 1064 void *__weak bpf_jit_alloc_exec(unsigned long size) 1065 { 1066 return execmem_alloc(EXECMEM_BPF, size); 1067 } 1068 1069 void __weak bpf_jit_free_exec(void *addr) 1070 { 1071 execmem_free(addr); 1072 } 1073 1074 struct bpf_binary_header * 1075 bpf_jit_binary_alloc(unsigned int proglen, u8 **image_ptr, 1076 unsigned int alignment, 1077 bpf_jit_fill_hole_t bpf_fill_ill_insns) 1078 { 1079 struct bpf_binary_header *hdr; 1080 u32 size, hole, start; 1081 1082 WARN_ON_ONCE(!is_power_of_2(alignment) || 1083 alignment > BPF_IMAGE_ALIGNMENT); 1084 1085 /* Most of BPF filters are really small, but if some of them 1086 * fill a page, allow at least 128 extra bytes to insert a 1087 * random section of illegal instructions. 1088 */ 1089 size = round_up(proglen + sizeof(*hdr) + 128, PAGE_SIZE); 1090 1091 if (bpf_jit_charge_modmem(size)) 1092 return NULL; 1093 hdr = bpf_jit_alloc_exec(size); 1094 if (!hdr) { 1095 bpf_jit_uncharge_modmem(size); 1096 return NULL; 1097 } 1098 1099 /* Fill space with illegal/arch-dep instructions. */ 1100 bpf_fill_ill_insns(hdr, size); 1101 1102 hdr->size = size; 1103 hole = min_t(unsigned int, size - (proglen + sizeof(*hdr)), 1104 PAGE_SIZE - sizeof(*hdr)); 1105 start = get_random_u32_below(hole) & ~(alignment - 1); 1106 1107 /* Leave a random number of instructions before BPF code. */ 1108 *image_ptr = &hdr->image[start]; 1109 1110 return hdr; 1111 } 1112 1113 void bpf_jit_binary_free(struct bpf_binary_header *hdr) 1114 { 1115 u32 size = hdr->size; 1116 1117 bpf_jit_free_exec(hdr); 1118 bpf_jit_uncharge_modmem(size); 1119 } 1120 1121 /* Allocate jit binary from bpf_prog_pack allocator. 1122 * Since the allocated memory is RO+X, the JIT engine cannot write directly 1123 * to the memory. To solve this problem, a RW buffer is also allocated at 1124 * as the same time. The JIT engine should calculate offsets based on the 1125 * RO memory address, but write JITed program to the RW buffer. Once the 1126 * JIT engine finishes, it calls bpf_jit_binary_pack_finalize, which copies 1127 * the JITed program to the RO memory. 1128 */ 1129 struct bpf_binary_header * 1130 bpf_jit_binary_pack_alloc(unsigned int proglen, u8 **image_ptr, 1131 unsigned int alignment, 1132 struct bpf_binary_header **rw_header, 1133 u8 **rw_image, 1134 bpf_jit_fill_hole_t bpf_fill_ill_insns) 1135 { 1136 struct bpf_binary_header *ro_header; 1137 u32 size, hole, start; 1138 1139 WARN_ON_ONCE(!is_power_of_2(alignment) || 1140 alignment > BPF_IMAGE_ALIGNMENT); 1141 1142 /* add 16 bytes for a random section of illegal instructions */ 1143 size = round_up(proglen + sizeof(*ro_header) + 16, BPF_PROG_CHUNK_SIZE); 1144 1145 if (bpf_jit_charge_modmem(size)) 1146 return NULL; 1147 ro_header = bpf_prog_pack_alloc(size, bpf_fill_ill_insns); 1148 if (!ro_header) { 1149 bpf_jit_uncharge_modmem(size); 1150 return NULL; 1151 } 1152 1153 *rw_header = kvmalloc(size, GFP_KERNEL); 1154 if (!*rw_header) { 1155 bpf_prog_pack_free(ro_header, size); 1156 bpf_jit_uncharge_modmem(size); 1157 return NULL; 1158 } 1159 1160 /* Fill space with illegal/arch-dep instructions. */ 1161 bpf_fill_ill_insns(*rw_header, size); 1162 (*rw_header)->size = size; 1163 1164 hole = min_t(unsigned int, size - (proglen + sizeof(*ro_header)), 1165 BPF_PROG_CHUNK_SIZE - sizeof(*ro_header)); 1166 start = get_random_u32_below(hole) & ~(alignment - 1); 1167 1168 *image_ptr = &ro_header->image[start]; 1169 *rw_image = &(*rw_header)->image[start]; 1170 1171 return ro_header; 1172 } 1173 1174 /* Copy JITed text from rw_header to its final location, the ro_header. */ 1175 int bpf_jit_binary_pack_finalize(struct bpf_binary_header *ro_header, 1176 struct bpf_binary_header *rw_header) 1177 { 1178 void *ptr; 1179 1180 ptr = bpf_arch_text_copy(ro_header, rw_header, rw_header->size); 1181 1182 kvfree(rw_header); 1183 1184 if (IS_ERR(ptr)) { 1185 bpf_prog_pack_free(ro_header, ro_header->size); 1186 return PTR_ERR(ptr); 1187 } 1188 return 0; 1189 } 1190 1191 /* bpf_jit_binary_pack_free is called in two different scenarios: 1192 * 1) when the program is freed after; 1193 * 2) when the JIT engine fails (before bpf_jit_binary_pack_finalize). 1194 * For case 2), we need to free both the RO memory and the RW buffer. 1195 * 1196 * bpf_jit_binary_pack_free requires proper ro_header->size. However, 1197 * bpf_jit_binary_pack_alloc does not set it. Therefore, ro_header->size 1198 * must be set with either bpf_jit_binary_pack_finalize (normal path) or 1199 * bpf_arch_text_copy (when jit fails). 1200 */ 1201 void bpf_jit_binary_pack_free(struct bpf_binary_header *ro_header, 1202 struct bpf_binary_header *rw_header) 1203 { 1204 u32 size = ro_header->size; 1205 1206 bpf_prog_pack_free(ro_header, size); 1207 kvfree(rw_header); 1208 bpf_jit_uncharge_modmem(size); 1209 } 1210 1211 struct bpf_binary_header * 1212 bpf_jit_binary_pack_hdr(const struct bpf_prog *fp) 1213 { 1214 unsigned long real_start = (unsigned long)fp->bpf_func; 1215 unsigned long addr; 1216 1217 addr = real_start & BPF_PROG_CHUNK_MASK; 1218 return (void *)addr; 1219 } 1220 1221 static inline struct bpf_binary_header * 1222 bpf_jit_binary_hdr(const struct bpf_prog *fp) 1223 { 1224 unsigned long real_start = (unsigned long)fp->bpf_func; 1225 unsigned long addr; 1226 1227 addr = real_start & PAGE_MASK; 1228 return (void *)addr; 1229 } 1230 1231 /* This symbol is only overridden by archs that have different 1232 * requirements than the usual eBPF JITs, f.e. when they only 1233 * implement cBPF JIT, do not set images read-only, etc. 1234 */ 1235 void __weak bpf_jit_free(struct bpf_prog *fp) 1236 { 1237 if (fp->jited) { 1238 struct bpf_binary_header *hdr = bpf_jit_binary_hdr(fp); 1239 1240 bpf_jit_binary_free(hdr); 1241 WARN_ON_ONCE(!bpf_prog_kallsyms_verify_off(fp)); 1242 } 1243 1244 bpf_prog_unlock_free(fp); 1245 } 1246 1247 int bpf_jit_get_func_addr(const struct bpf_prog *prog, 1248 const struct bpf_insn *insn, bool extra_pass, 1249 u64 *func_addr, bool *func_addr_fixed) 1250 { 1251 s16 off = insn->off; 1252 s32 imm = insn->imm; 1253 u8 *addr; 1254 int err; 1255 1256 *func_addr_fixed = insn->src_reg != BPF_PSEUDO_CALL; 1257 if (!*func_addr_fixed) { 1258 /* Place-holder address till the last pass has collected 1259 * all addresses for JITed subprograms in which case we 1260 * can pick them up from prog->aux. 1261 */ 1262 if (!extra_pass) 1263 addr = NULL; 1264 else if (prog->aux->func && 1265 off >= 0 && off < prog->aux->real_func_cnt) 1266 addr = (u8 *)prog->aux->func[off]->bpf_func; 1267 else 1268 return -EINVAL; 1269 } else if (insn->src_reg == BPF_PSEUDO_KFUNC_CALL && 1270 bpf_jit_supports_far_kfunc_call()) { 1271 err = bpf_get_kfunc_addr(prog, insn->imm, insn->off, &addr); 1272 if (err) 1273 return err; 1274 } else { 1275 /* Address of a BPF helper call. Since part of the core 1276 * kernel, it's always at a fixed location. __bpf_call_base 1277 * and the helper with imm relative to it are both in core 1278 * kernel. 1279 */ 1280 addr = (u8 *)__bpf_call_base + imm; 1281 } 1282 1283 *func_addr = (unsigned long)addr; 1284 return 0; 1285 } 1286 1287 const char *bpf_jit_get_prog_name(struct bpf_prog *prog) 1288 { 1289 if (prog->aux->ksym.prog) 1290 return prog->aux->ksym.name; 1291 return prog->aux->name; 1292 } 1293 1294 static int bpf_jit_blind_insn(const struct bpf_insn *from, 1295 const struct bpf_insn *aux, 1296 struct bpf_insn *to_buff, 1297 bool emit_zext) 1298 { 1299 struct bpf_insn *to = to_buff; 1300 u32 imm_rnd = get_random_u32(); 1301 s16 off; 1302 1303 BUILD_BUG_ON(BPF_REG_AX + 1 != MAX_BPF_JIT_REG); 1304 BUILD_BUG_ON(MAX_BPF_REG + 1 != MAX_BPF_JIT_REG); 1305 1306 /* Constraints on AX register: 1307 * 1308 * AX register is inaccessible from user space. It is mapped in 1309 * all JITs, and used here for constant blinding rewrites. It is 1310 * typically "stateless" meaning its contents are only valid within 1311 * the executed instruction, but not across several instructions. 1312 * There are a few exceptions however which are further detailed 1313 * below. 1314 * 1315 * Constant blinding is only used by JITs, not in the interpreter. 1316 * The interpreter uses AX in some occasions as a local temporary 1317 * register e.g. in DIV or MOD instructions. 1318 * 1319 * In restricted circumstances, the verifier can also use the AX 1320 * register for rewrites as long as they do not interfere with 1321 * the above cases! 1322 */ 1323 if (from->dst_reg == BPF_REG_AX || from->src_reg == BPF_REG_AX) 1324 goto out; 1325 1326 if (from->imm == 0 && 1327 (from->code == (BPF_ALU | BPF_MOV | BPF_K) || 1328 from->code == (BPF_ALU64 | BPF_MOV | BPF_K))) { 1329 *to++ = BPF_ALU64_REG(BPF_XOR, from->dst_reg, from->dst_reg); 1330 goto out; 1331 } 1332 1333 switch (from->code) { 1334 case BPF_ALU | BPF_ADD | BPF_K: 1335 case BPF_ALU | BPF_SUB | BPF_K: 1336 case BPF_ALU | BPF_AND | BPF_K: 1337 case BPF_ALU | BPF_OR | BPF_K: 1338 case BPF_ALU | BPF_XOR | BPF_K: 1339 case BPF_ALU | BPF_MUL | BPF_K: 1340 case BPF_ALU | BPF_MOV | BPF_K: 1341 case BPF_ALU | BPF_DIV | BPF_K: 1342 case BPF_ALU | BPF_MOD | BPF_K: 1343 *to++ = BPF_ALU32_IMM(BPF_MOV, BPF_REG_AX, imm_rnd ^ from->imm); 1344 *to++ = BPF_ALU32_IMM(BPF_XOR, BPF_REG_AX, imm_rnd); 1345 *to++ = BPF_ALU32_REG_OFF(from->code, from->dst_reg, BPF_REG_AX, from->off); 1346 break; 1347 1348 case BPF_ALU64 | BPF_ADD | BPF_K: 1349 case BPF_ALU64 | BPF_SUB | BPF_K: 1350 case BPF_ALU64 | BPF_AND | BPF_K: 1351 case BPF_ALU64 | BPF_OR | BPF_K: 1352 case BPF_ALU64 | BPF_XOR | BPF_K: 1353 case BPF_ALU64 | BPF_MUL | BPF_K: 1354 case BPF_ALU64 | BPF_MOV | BPF_K: 1355 case BPF_ALU64 | BPF_DIV | BPF_K: 1356 case BPF_ALU64 | BPF_MOD | BPF_K: 1357 *to++ = BPF_ALU64_IMM(BPF_MOV, BPF_REG_AX, imm_rnd ^ from->imm); 1358 *to++ = BPF_ALU64_IMM(BPF_XOR, BPF_REG_AX, imm_rnd); 1359 *to++ = BPF_ALU64_REG_OFF(from->code, from->dst_reg, BPF_REG_AX, from->off); 1360 break; 1361 1362 case BPF_JMP | BPF_JEQ | BPF_K: 1363 case BPF_JMP | BPF_JNE | BPF_K: 1364 case BPF_JMP | BPF_JGT | BPF_K: 1365 case BPF_JMP | BPF_JLT | BPF_K: 1366 case BPF_JMP | BPF_JGE | BPF_K: 1367 case BPF_JMP | BPF_JLE | BPF_K: 1368 case BPF_JMP | BPF_JSGT | BPF_K: 1369 case BPF_JMP | BPF_JSLT | BPF_K: 1370 case BPF_JMP | BPF_JSGE | BPF_K: 1371 case BPF_JMP | BPF_JSLE | BPF_K: 1372 case BPF_JMP | BPF_JSET | BPF_K: 1373 /* Accommodate for extra offset in case of a backjump. */ 1374 off = from->off; 1375 if (off < 0) 1376 off -= 2; 1377 *to++ = BPF_ALU64_IMM(BPF_MOV, BPF_REG_AX, imm_rnd ^ from->imm); 1378 *to++ = BPF_ALU64_IMM(BPF_XOR, BPF_REG_AX, imm_rnd); 1379 *to++ = BPF_JMP_REG(from->code, from->dst_reg, BPF_REG_AX, off); 1380 break; 1381 1382 case BPF_JMP32 | BPF_JEQ | BPF_K: 1383 case BPF_JMP32 | BPF_JNE | BPF_K: 1384 case BPF_JMP32 | BPF_JGT | BPF_K: 1385 case BPF_JMP32 | BPF_JLT | BPF_K: 1386 case BPF_JMP32 | BPF_JGE | BPF_K: 1387 case BPF_JMP32 | BPF_JLE | BPF_K: 1388 case BPF_JMP32 | BPF_JSGT | BPF_K: 1389 case BPF_JMP32 | BPF_JSLT | BPF_K: 1390 case BPF_JMP32 | BPF_JSGE | BPF_K: 1391 case BPF_JMP32 | BPF_JSLE | BPF_K: 1392 case BPF_JMP32 | BPF_JSET | BPF_K: 1393 /* Accommodate for extra offset in case of a backjump. */ 1394 off = from->off; 1395 if (off < 0) 1396 off -= 2; 1397 *to++ = BPF_ALU32_IMM(BPF_MOV, BPF_REG_AX, imm_rnd ^ from->imm); 1398 *to++ = BPF_ALU32_IMM(BPF_XOR, BPF_REG_AX, imm_rnd); 1399 *to++ = BPF_JMP32_REG(from->code, from->dst_reg, BPF_REG_AX, 1400 off); 1401 break; 1402 1403 case BPF_LD | BPF_IMM | BPF_DW: 1404 *to++ = BPF_ALU64_IMM(BPF_MOV, BPF_REG_AX, imm_rnd ^ aux[1].imm); 1405 *to++ = BPF_ALU64_IMM(BPF_XOR, BPF_REG_AX, imm_rnd); 1406 *to++ = BPF_ALU64_IMM(BPF_LSH, BPF_REG_AX, 32); 1407 *to++ = BPF_ALU64_REG(BPF_MOV, aux[0].dst_reg, BPF_REG_AX); 1408 break; 1409 case 0: /* Part 2 of BPF_LD | BPF_IMM | BPF_DW. */ 1410 *to++ = BPF_ALU32_IMM(BPF_MOV, BPF_REG_AX, imm_rnd ^ aux[0].imm); 1411 *to++ = BPF_ALU32_IMM(BPF_XOR, BPF_REG_AX, imm_rnd); 1412 if (emit_zext) 1413 *to++ = BPF_ZEXT_REG(BPF_REG_AX); 1414 *to++ = BPF_ALU64_REG(BPF_OR, aux[0].dst_reg, BPF_REG_AX); 1415 break; 1416 1417 case BPF_ST | BPF_MEM | BPF_DW: 1418 case BPF_ST | BPF_MEM | BPF_W: 1419 case BPF_ST | BPF_MEM | BPF_H: 1420 case BPF_ST | BPF_MEM | BPF_B: 1421 *to++ = BPF_ALU64_IMM(BPF_MOV, BPF_REG_AX, imm_rnd ^ from->imm); 1422 *to++ = BPF_ALU64_IMM(BPF_XOR, BPF_REG_AX, imm_rnd); 1423 *to++ = BPF_STX_MEM(from->code, from->dst_reg, BPF_REG_AX, from->off); 1424 break; 1425 1426 case BPF_ST | BPF_PROBE_MEM32 | BPF_DW: 1427 case BPF_ST | BPF_PROBE_MEM32 | BPF_W: 1428 case BPF_ST | BPF_PROBE_MEM32 | BPF_H: 1429 case BPF_ST | BPF_PROBE_MEM32 | BPF_B: 1430 *to++ = BPF_ALU64_IMM(BPF_MOV, BPF_REG_AX, imm_rnd ^ 1431 from->imm); 1432 *to++ = BPF_ALU64_IMM(BPF_XOR, BPF_REG_AX, imm_rnd); 1433 /* 1434 * Cannot use BPF_STX_MEM() macro here as it 1435 * hardcodes BPF_MEM mode, losing PROBE_MEM32 1436 * and breaking arena addressing in the JIT. 1437 */ 1438 *to++ = (struct bpf_insn) { 1439 .code = BPF_STX | BPF_PROBE_MEM32 | 1440 BPF_SIZE(from->code), 1441 .dst_reg = from->dst_reg, 1442 .src_reg = BPF_REG_AX, 1443 .off = from->off, 1444 }; 1445 break; 1446 } 1447 out: 1448 return to - to_buff; 1449 } 1450 1451 static struct bpf_prog *bpf_prog_clone_create(struct bpf_prog *fp_other, 1452 gfp_t gfp_extra_flags) 1453 { 1454 gfp_t gfp_flags = GFP_KERNEL | __GFP_ZERO | gfp_extra_flags; 1455 struct bpf_prog *fp; 1456 1457 fp = __vmalloc(fp_other->pages * PAGE_SIZE, gfp_flags); 1458 if (fp != NULL) { 1459 /* aux->prog still points to the fp_other one, so 1460 * when promoting the clone to the real program, 1461 * this still needs to be adapted. 1462 */ 1463 memcpy(fp, fp_other, fp_other->pages * PAGE_SIZE); 1464 } 1465 1466 return fp; 1467 } 1468 1469 static void bpf_prog_clone_free(struct bpf_prog *fp) 1470 { 1471 /* aux was stolen by the other clone, so we cannot free 1472 * it from this path! It will be freed eventually by the 1473 * other program on release. 1474 * 1475 * At this point, we don't need a deferred release since 1476 * clone is guaranteed to not be locked. 1477 */ 1478 fp->aux = NULL; 1479 fp->stats = NULL; 1480 fp->active = NULL; 1481 __bpf_prog_free(fp); 1482 } 1483 1484 void bpf_jit_prog_release_other(struct bpf_prog *fp, struct bpf_prog *fp_other) 1485 { 1486 /* We have to repoint aux->prog to self, as we don't 1487 * know whether fp here is the clone or the original. 1488 */ 1489 fp->aux->prog = fp; 1490 bpf_prog_clone_free(fp_other); 1491 } 1492 1493 static void adjust_insn_arrays(struct bpf_prog *prog, u32 off, u32 len) 1494 { 1495 #ifdef CONFIG_BPF_SYSCALL 1496 struct bpf_map *map; 1497 int i; 1498 1499 if (len <= 1) 1500 return; 1501 1502 for (i = 0; i < prog->aux->used_map_cnt; i++) { 1503 map = prog->aux->used_maps[i]; 1504 if (map->map_type == BPF_MAP_TYPE_INSN_ARRAY) 1505 bpf_insn_array_adjust(map, off, len); 1506 } 1507 #endif 1508 } 1509 1510 struct bpf_prog *bpf_jit_blind_constants(struct bpf_prog *prog) 1511 { 1512 struct bpf_insn insn_buff[16], aux[2]; 1513 struct bpf_prog *clone, *tmp; 1514 int insn_delta, insn_cnt; 1515 struct bpf_insn *insn; 1516 int i, rewritten; 1517 1518 if (!prog->blinding_requested || prog->blinded) 1519 return prog; 1520 1521 clone = bpf_prog_clone_create(prog, GFP_USER); 1522 if (!clone) 1523 return ERR_PTR(-ENOMEM); 1524 1525 insn_cnt = clone->len; 1526 insn = clone->insnsi; 1527 1528 for (i = 0; i < insn_cnt; i++, insn++) { 1529 if (bpf_pseudo_func(insn)) { 1530 /* ld_imm64 with an address of bpf subprog is not 1531 * a user controlled constant. Don't randomize it, 1532 * since it will conflict with jit_subprogs() logic. 1533 */ 1534 insn++; 1535 i++; 1536 continue; 1537 } 1538 1539 /* We temporarily need to hold the original ld64 insn 1540 * so that we can still access the first part in the 1541 * second blinding run. 1542 */ 1543 if (insn[0].code == (BPF_LD | BPF_IMM | BPF_DW) && 1544 insn[1].code == 0) 1545 memcpy(aux, insn, sizeof(aux)); 1546 1547 rewritten = bpf_jit_blind_insn(insn, aux, insn_buff, 1548 clone->aux->verifier_zext); 1549 if (!rewritten) 1550 continue; 1551 1552 tmp = bpf_patch_insn_single(clone, i, insn_buff, rewritten); 1553 if (IS_ERR(tmp)) { 1554 /* Patching may have repointed aux->prog during 1555 * realloc from the original one, so we need to 1556 * fix it up here on error. 1557 */ 1558 bpf_jit_prog_release_other(prog, clone); 1559 return tmp; 1560 } 1561 1562 clone = tmp; 1563 insn_delta = rewritten - 1; 1564 1565 /* Instructions arrays must be updated using absolute xlated offsets */ 1566 adjust_insn_arrays(clone, prog->aux->subprog_start + i, rewritten); 1567 1568 /* Walk new program and skip insns we just inserted. */ 1569 insn = clone->insnsi + i + insn_delta; 1570 insn_cnt += insn_delta; 1571 i += insn_delta; 1572 } 1573 1574 clone->blinded = 1; 1575 return clone; 1576 } 1577 #endif /* CONFIG_BPF_JIT */ 1578 1579 /* Base function for offset calculation. Needs to go into .text section, 1580 * therefore keeping it non-static as well; will also be used by JITs 1581 * anyway later on, so do not let the compiler omit it. This also needs 1582 * to go into kallsyms for correlation from e.g. bpftool, so naming 1583 * must not change. 1584 */ 1585 noinline u64 __bpf_call_base(u64 r1, u64 r2, u64 r3, u64 r4, u64 r5) 1586 { 1587 return 0; 1588 } 1589 EXPORT_SYMBOL_GPL(__bpf_call_base); 1590 1591 /* All UAPI available opcodes. */ 1592 #define BPF_INSN_MAP(INSN_2, INSN_3) \ 1593 /* 32 bit ALU operations. */ \ 1594 /* Register based. */ \ 1595 INSN_3(ALU, ADD, X), \ 1596 INSN_3(ALU, SUB, X), \ 1597 INSN_3(ALU, AND, X), \ 1598 INSN_3(ALU, OR, X), \ 1599 INSN_3(ALU, LSH, X), \ 1600 INSN_3(ALU, RSH, X), \ 1601 INSN_3(ALU, XOR, X), \ 1602 INSN_3(ALU, MUL, X), \ 1603 INSN_3(ALU, MOV, X), \ 1604 INSN_3(ALU, ARSH, X), \ 1605 INSN_3(ALU, DIV, X), \ 1606 INSN_3(ALU, MOD, X), \ 1607 INSN_2(ALU, NEG), \ 1608 INSN_3(ALU, END, TO_BE), \ 1609 INSN_3(ALU, END, TO_LE), \ 1610 /* Immediate based. */ \ 1611 INSN_3(ALU, ADD, K), \ 1612 INSN_3(ALU, SUB, K), \ 1613 INSN_3(ALU, AND, K), \ 1614 INSN_3(ALU, OR, K), \ 1615 INSN_3(ALU, LSH, K), \ 1616 INSN_3(ALU, RSH, K), \ 1617 INSN_3(ALU, XOR, K), \ 1618 INSN_3(ALU, MUL, K), \ 1619 INSN_3(ALU, MOV, K), \ 1620 INSN_3(ALU, ARSH, K), \ 1621 INSN_3(ALU, DIV, K), \ 1622 INSN_3(ALU, MOD, K), \ 1623 /* 64 bit ALU operations. */ \ 1624 /* Register based. */ \ 1625 INSN_3(ALU64, ADD, X), \ 1626 INSN_3(ALU64, SUB, X), \ 1627 INSN_3(ALU64, AND, X), \ 1628 INSN_3(ALU64, OR, X), \ 1629 INSN_3(ALU64, LSH, X), \ 1630 INSN_3(ALU64, RSH, X), \ 1631 INSN_3(ALU64, XOR, X), \ 1632 INSN_3(ALU64, MUL, X), \ 1633 INSN_3(ALU64, MOV, X), \ 1634 INSN_3(ALU64, ARSH, X), \ 1635 INSN_3(ALU64, DIV, X), \ 1636 INSN_3(ALU64, MOD, X), \ 1637 INSN_2(ALU64, NEG), \ 1638 INSN_3(ALU64, END, TO_LE), \ 1639 /* Immediate based. */ \ 1640 INSN_3(ALU64, ADD, K), \ 1641 INSN_3(ALU64, SUB, K), \ 1642 INSN_3(ALU64, AND, K), \ 1643 INSN_3(ALU64, OR, K), \ 1644 INSN_3(ALU64, LSH, K), \ 1645 INSN_3(ALU64, RSH, K), \ 1646 INSN_3(ALU64, XOR, K), \ 1647 INSN_3(ALU64, MUL, K), \ 1648 INSN_3(ALU64, MOV, K), \ 1649 INSN_3(ALU64, ARSH, K), \ 1650 INSN_3(ALU64, DIV, K), \ 1651 INSN_3(ALU64, MOD, K), \ 1652 /* Call instruction. */ \ 1653 INSN_2(JMP, CALL), \ 1654 /* Exit instruction. */ \ 1655 INSN_2(JMP, EXIT), \ 1656 /* 32-bit Jump instructions. */ \ 1657 /* Register based. */ \ 1658 INSN_3(JMP32, JEQ, X), \ 1659 INSN_3(JMP32, JNE, X), \ 1660 INSN_3(JMP32, JGT, X), \ 1661 INSN_3(JMP32, JLT, X), \ 1662 INSN_3(JMP32, JGE, X), \ 1663 INSN_3(JMP32, JLE, X), \ 1664 INSN_3(JMP32, JSGT, X), \ 1665 INSN_3(JMP32, JSLT, X), \ 1666 INSN_3(JMP32, JSGE, X), \ 1667 INSN_3(JMP32, JSLE, X), \ 1668 INSN_3(JMP32, JSET, X), \ 1669 /* Immediate based. */ \ 1670 INSN_3(JMP32, JEQ, K), \ 1671 INSN_3(JMP32, JNE, K), \ 1672 INSN_3(JMP32, JGT, K), \ 1673 INSN_3(JMP32, JLT, K), \ 1674 INSN_3(JMP32, JGE, K), \ 1675 INSN_3(JMP32, JLE, K), \ 1676 INSN_3(JMP32, JSGT, K), \ 1677 INSN_3(JMP32, JSLT, K), \ 1678 INSN_3(JMP32, JSGE, K), \ 1679 INSN_3(JMP32, JSLE, K), \ 1680 INSN_3(JMP32, JSET, K), \ 1681 /* Jump instructions. */ \ 1682 /* Register based. */ \ 1683 INSN_3(JMP, JEQ, X), \ 1684 INSN_3(JMP, JNE, X), \ 1685 INSN_3(JMP, JGT, X), \ 1686 INSN_3(JMP, JLT, X), \ 1687 INSN_3(JMP, JGE, X), \ 1688 INSN_3(JMP, JLE, X), \ 1689 INSN_3(JMP, JSGT, X), \ 1690 INSN_3(JMP, JSLT, X), \ 1691 INSN_3(JMP, JSGE, X), \ 1692 INSN_3(JMP, JSLE, X), \ 1693 INSN_3(JMP, JSET, X), \ 1694 /* Immediate based. */ \ 1695 INSN_3(JMP, JEQ, K), \ 1696 INSN_3(JMP, JNE, K), \ 1697 INSN_3(JMP, JGT, K), \ 1698 INSN_3(JMP, JLT, K), \ 1699 INSN_3(JMP, JGE, K), \ 1700 INSN_3(JMP, JLE, K), \ 1701 INSN_3(JMP, JSGT, K), \ 1702 INSN_3(JMP, JSLT, K), \ 1703 INSN_3(JMP, JSGE, K), \ 1704 INSN_3(JMP, JSLE, K), \ 1705 INSN_3(JMP, JSET, K), \ 1706 INSN_2(JMP, JA), \ 1707 INSN_2(JMP32, JA), \ 1708 /* Atomic operations. */ \ 1709 INSN_3(STX, ATOMIC, B), \ 1710 INSN_3(STX, ATOMIC, H), \ 1711 INSN_3(STX, ATOMIC, W), \ 1712 INSN_3(STX, ATOMIC, DW), \ 1713 /* Store instructions. */ \ 1714 /* Register based. */ \ 1715 INSN_3(STX, MEM, B), \ 1716 INSN_3(STX, MEM, H), \ 1717 INSN_3(STX, MEM, W), \ 1718 INSN_3(STX, MEM, DW), \ 1719 /* Immediate based. */ \ 1720 INSN_3(ST, MEM, B), \ 1721 INSN_3(ST, MEM, H), \ 1722 INSN_3(ST, MEM, W), \ 1723 INSN_3(ST, MEM, DW), \ 1724 /* Load instructions. */ \ 1725 /* Register based. */ \ 1726 INSN_3(LDX, MEM, B), \ 1727 INSN_3(LDX, MEM, H), \ 1728 INSN_3(LDX, MEM, W), \ 1729 INSN_3(LDX, MEM, DW), \ 1730 INSN_3(LDX, MEMSX, B), \ 1731 INSN_3(LDX, MEMSX, H), \ 1732 INSN_3(LDX, MEMSX, W), \ 1733 /* Immediate based. */ \ 1734 INSN_3(LD, IMM, DW) 1735 1736 bool bpf_opcode_in_insntable(u8 code) 1737 { 1738 #define BPF_INSN_2_TBL(x, y) [BPF_##x | BPF_##y] = true 1739 #define BPF_INSN_3_TBL(x, y, z) [BPF_##x | BPF_##y | BPF_##z] = true 1740 static const bool public_insntable[256] = { 1741 [0 ... 255] = false, 1742 /* Now overwrite non-defaults ... */ 1743 BPF_INSN_MAP(BPF_INSN_2_TBL, BPF_INSN_3_TBL), 1744 /* UAPI exposed, but rewritten opcodes. cBPF carry-over. */ 1745 [BPF_LD | BPF_ABS | BPF_B] = true, 1746 [BPF_LD | BPF_ABS | BPF_H] = true, 1747 [BPF_LD | BPF_ABS | BPF_W] = true, 1748 [BPF_LD | BPF_IND | BPF_B] = true, 1749 [BPF_LD | BPF_IND | BPF_H] = true, 1750 [BPF_LD | BPF_IND | BPF_W] = true, 1751 [BPF_JMP | BPF_JA | BPF_X] = true, 1752 [BPF_JMP | BPF_JCOND] = true, 1753 }; 1754 #undef BPF_INSN_3_TBL 1755 #undef BPF_INSN_2_TBL 1756 return public_insntable[code]; 1757 } 1758 1759 #ifndef CONFIG_BPF_JIT_ALWAYS_ON 1760 /* Absolute value of s32 without undefined behavior for S32_MIN */ 1761 static u32 abs_s32(s32 x) 1762 { 1763 return x >= 0 ? (u32)x : -(u32)x; 1764 } 1765 1766 /** 1767 * ___bpf_prog_run - run eBPF program on a given context 1768 * @regs: is the array of MAX_BPF_EXT_REG eBPF pseudo-registers 1769 * @insn: is the array of eBPF instructions 1770 * 1771 * Decode and execute eBPF instructions. 1772 * 1773 * Return: whatever value is in %BPF_R0 at program exit 1774 */ 1775 static u64 ___bpf_prog_run(u64 *regs, const struct bpf_insn *insn) 1776 { 1777 #define BPF_INSN_2_LBL(x, y) [BPF_##x | BPF_##y] = &&x##_##y 1778 #define BPF_INSN_3_LBL(x, y, z) [BPF_##x | BPF_##y | BPF_##z] = &&x##_##y##_##z 1779 static const void * const jumptable[256] __annotate_jump_table = { 1780 [0 ... 255] = &&default_label, 1781 /* Now overwrite non-defaults ... */ 1782 BPF_INSN_MAP(BPF_INSN_2_LBL, BPF_INSN_3_LBL), 1783 /* Non-UAPI available opcodes. */ 1784 [BPF_JMP | BPF_CALL_ARGS] = &&JMP_CALL_ARGS, 1785 [BPF_JMP | BPF_TAIL_CALL] = &&JMP_TAIL_CALL, 1786 [BPF_ST | BPF_NOSPEC] = &&ST_NOSPEC, 1787 [BPF_LDX | BPF_PROBE_MEM | BPF_B] = &&LDX_PROBE_MEM_B, 1788 [BPF_LDX | BPF_PROBE_MEM | BPF_H] = &&LDX_PROBE_MEM_H, 1789 [BPF_LDX | BPF_PROBE_MEM | BPF_W] = &&LDX_PROBE_MEM_W, 1790 [BPF_LDX | BPF_PROBE_MEM | BPF_DW] = &&LDX_PROBE_MEM_DW, 1791 [BPF_LDX | BPF_PROBE_MEMSX | BPF_B] = &&LDX_PROBE_MEMSX_B, 1792 [BPF_LDX | BPF_PROBE_MEMSX | BPF_H] = &&LDX_PROBE_MEMSX_H, 1793 [BPF_LDX | BPF_PROBE_MEMSX | BPF_W] = &&LDX_PROBE_MEMSX_W, 1794 }; 1795 #undef BPF_INSN_3_LBL 1796 #undef BPF_INSN_2_LBL 1797 u32 tail_call_cnt = 0; 1798 1799 #define CONT ({ insn++; goto select_insn; }) 1800 #define CONT_JMP ({ insn++; goto select_insn; }) 1801 1802 select_insn: 1803 goto *jumptable[insn->code]; 1804 1805 /* Explicitly mask the register-based shift amounts with 63 or 31 1806 * to avoid undefined behavior. Normally this won't affect the 1807 * generated code, for example, in case of native 64 bit archs such 1808 * as x86-64 or arm64, the compiler is optimizing the AND away for 1809 * the interpreter. In case of JITs, each of the JIT backends compiles 1810 * the BPF shift operations to machine instructions which produce 1811 * implementation-defined results in such a case; the resulting 1812 * contents of the register may be arbitrary, but program behaviour 1813 * as a whole remains defined. In other words, in case of JIT backends, 1814 * the AND must /not/ be added to the emitted LSH/RSH/ARSH translation. 1815 */ 1816 /* ALU (shifts) */ 1817 #define SHT(OPCODE, OP) \ 1818 ALU64_##OPCODE##_X: \ 1819 DST = DST OP (SRC & 63); \ 1820 CONT; \ 1821 ALU_##OPCODE##_X: \ 1822 DST = (u32) DST OP ((u32) SRC & 31); \ 1823 CONT; \ 1824 ALU64_##OPCODE##_K: \ 1825 DST = DST OP IMM; \ 1826 CONT; \ 1827 ALU_##OPCODE##_K: \ 1828 DST = (u32) DST OP (u32) IMM; \ 1829 CONT; 1830 /* ALU (rest) */ 1831 #define ALU(OPCODE, OP) \ 1832 ALU64_##OPCODE##_X: \ 1833 DST = DST OP SRC; \ 1834 CONT; \ 1835 ALU_##OPCODE##_X: \ 1836 DST = (u32) DST OP (u32) SRC; \ 1837 CONT; \ 1838 ALU64_##OPCODE##_K: \ 1839 DST = DST OP IMM; \ 1840 CONT; \ 1841 ALU_##OPCODE##_K: \ 1842 DST = (u32) DST OP (u32) IMM; \ 1843 CONT; 1844 ALU(ADD, +) 1845 ALU(SUB, -) 1846 ALU(AND, &) 1847 ALU(OR, |) 1848 ALU(XOR, ^) 1849 ALU(MUL, *) 1850 SHT(LSH, <<) 1851 SHT(RSH, >>) 1852 #undef SHT 1853 #undef ALU 1854 ALU_NEG: 1855 DST = (u32) -DST; 1856 CONT; 1857 ALU64_NEG: 1858 DST = -DST; 1859 CONT; 1860 ALU_MOV_X: 1861 switch (OFF) { 1862 case 0: 1863 DST = (u32) SRC; 1864 break; 1865 case 8: 1866 DST = (u32)(s8) SRC; 1867 break; 1868 case 16: 1869 DST = (u32)(s16) SRC; 1870 break; 1871 } 1872 CONT; 1873 ALU_MOV_K: 1874 DST = (u32) IMM; 1875 CONT; 1876 ALU64_MOV_X: 1877 switch (OFF) { 1878 case 0: 1879 DST = SRC; 1880 break; 1881 case 8: 1882 DST = (s8) SRC; 1883 break; 1884 case 16: 1885 DST = (s16) SRC; 1886 break; 1887 case 32: 1888 DST = (s32) SRC; 1889 break; 1890 } 1891 CONT; 1892 ALU64_MOV_K: 1893 DST = IMM; 1894 CONT; 1895 LD_IMM_DW: 1896 DST = (u64) (u32) insn[0].imm | ((u64) (u32) insn[1].imm) << 32; 1897 insn++; 1898 CONT; 1899 ALU_ARSH_X: 1900 DST = (u64) (u32) (((s32) DST) >> (SRC & 31)); 1901 CONT; 1902 ALU_ARSH_K: 1903 DST = (u64) (u32) (((s32) DST) >> IMM); 1904 CONT; 1905 ALU64_ARSH_X: 1906 (*(s64 *) &DST) >>= (SRC & 63); 1907 CONT; 1908 ALU64_ARSH_K: 1909 (*(s64 *) &DST) >>= IMM; 1910 CONT; 1911 ALU64_MOD_X: 1912 switch (OFF) { 1913 case 0: 1914 div64_u64_rem(DST, SRC, &AX); 1915 DST = AX; 1916 break; 1917 case 1: 1918 AX = div64_s64(DST, SRC); 1919 DST = DST - AX * SRC; 1920 break; 1921 } 1922 CONT; 1923 ALU_MOD_X: 1924 switch (OFF) { 1925 case 0: 1926 AX = (u32) DST; 1927 DST = do_div(AX, (u32) SRC); 1928 break; 1929 case 1: 1930 AX = abs_s32((s32)DST); 1931 AX = do_div(AX, abs_s32((s32)SRC)); 1932 if ((s32)DST < 0) 1933 DST = (u32)-AX; 1934 else 1935 DST = (u32)AX; 1936 break; 1937 } 1938 CONT; 1939 ALU64_MOD_K: 1940 switch (OFF) { 1941 case 0: 1942 div64_u64_rem(DST, IMM, &AX); 1943 DST = AX; 1944 break; 1945 case 1: 1946 AX = div64_s64(DST, IMM); 1947 DST = DST - AX * IMM; 1948 break; 1949 } 1950 CONT; 1951 ALU_MOD_K: 1952 switch (OFF) { 1953 case 0: 1954 AX = (u32) DST; 1955 DST = do_div(AX, (u32) IMM); 1956 break; 1957 case 1: 1958 AX = abs_s32((s32)DST); 1959 AX = do_div(AX, abs_s32((s32)IMM)); 1960 if ((s32)DST < 0) 1961 DST = (u32)-AX; 1962 else 1963 DST = (u32)AX; 1964 break; 1965 } 1966 CONT; 1967 ALU64_DIV_X: 1968 switch (OFF) { 1969 case 0: 1970 DST = div64_u64(DST, SRC); 1971 break; 1972 case 1: 1973 DST = div64_s64(DST, SRC); 1974 break; 1975 } 1976 CONT; 1977 ALU_DIV_X: 1978 switch (OFF) { 1979 case 0: 1980 AX = (u32) DST; 1981 do_div(AX, (u32) SRC); 1982 DST = (u32) AX; 1983 break; 1984 case 1: 1985 AX = abs_s32((s32)DST); 1986 do_div(AX, abs_s32((s32)SRC)); 1987 if (((s32)DST < 0) == ((s32)SRC < 0)) 1988 DST = (u32)AX; 1989 else 1990 DST = (u32)-AX; 1991 break; 1992 } 1993 CONT; 1994 ALU64_DIV_K: 1995 switch (OFF) { 1996 case 0: 1997 DST = div64_u64(DST, IMM); 1998 break; 1999 case 1: 2000 DST = div64_s64(DST, IMM); 2001 break; 2002 } 2003 CONT; 2004 ALU_DIV_K: 2005 switch (OFF) { 2006 case 0: 2007 AX = (u32) DST; 2008 do_div(AX, (u32) IMM); 2009 DST = (u32) AX; 2010 break; 2011 case 1: 2012 AX = abs_s32((s32)DST); 2013 do_div(AX, abs_s32((s32)IMM)); 2014 if (((s32)DST < 0) == ((s32)IMM < 0)) 2015 DST = (u32)AX; 2016 else 2017 DST = (u32)-AX; 2018 break; 2019 } 2020 CONT; 2021 ALU_END_TO_BE: 2022 switch (IMM) { 2023 case 16: 2024 DST = (__force u16) cpu_to_be16(DST); 2025 break; 2026 case 32: 2027 DST = (__force u32) cpu_to_be32(DST); 2028 break; 2029 case 64: 2030 DST = (__force u64) cpu_to_be64(DST); 2031 break; 2032 } 2033 CONT; 2034 ALU_END_TO_LE: 2035 switch (IMM) { 2036 case 16: 2037 DST = (__force u16) cpu_to_le16(DST); 2038 break; 2039 case 32: 2040 DST = (__force u32) cpu_to_le32(DST); 2041 break; 2042 case 64: 2043 DST = (__force u64) cpu_to_le64(DST); 2044 break; 2045 } 2046 CONT; 2047 ALU64_END_TO_LE: 2048 switch (IMM) { 2049 case 16: 2050 DST = (__force u16) __swab16(DST); 2051 break; 2052 case 32: 2053 DST = (__force u32) __swab32(DST); 2054 break; 2055 case 64: 2056 DST = (__force u64) __swab64(DST); 2057 break; 2058 } 2059 CONT; 2060 2061 /* CALL */ 2062 JMP_CALL: 2063 /* Function call scratches BPF_R1-BPF_R5 registers, 2064 * preserves BPF_R6-BPF_R9, and stores return value 2065 * into BPF_R0. 2066 */ 2067 BPF_R0 = (__bpf_call_base + insn->imm)(BPF_R1, BPF_R2, BPF_R3, 2068 BPF_R4, BPF_R5); 2069 CONT; 2070 2071 JMP_CALL_ARGS: 2072 BPF_R0 = (__bpf_call_base_args + insn->imm)(BPF_R1, BPF_R2, 2073 BPF_R3, BPF_R4, 2074 BPF_R5, 2075 insn + insn->off + 1); 2076 CONT; 2077 2078 JMP_TAIL_CALL: { 2079 struct bpf_map *map = (struct bpf_map *) (unsigned long) BPF_R2; 2080 struct bpf_array *array = container_of(map, struct bpf_array, map); 2081 struct bpf_prog *prog; 2082 u32 index = BPF_R3; 2083 2084 if (unlikely(index >= array->map.max_entries)) 2085 goto out; 2086 2087 if (unlikely(tail_call_cnt >= MAX_TAIL_CALL_CNT)) 2088 goto out; 2089 2090 tail_call_cnt++; 2091 2092 prog = READ_ONCE(array->ptrs[index]); 2093 if (!prog) 2094 goto out; 2095 2096 /* ARG1 at this point is guaranteed to point to CTX from 2097 * the verifier side due to the fact that the tail call is 2098 * handled like a helper, that is, bpf_tail_call_proto, 2099 * where arg1_type is ARG_PTR_TO_CTX. 2100 */ 2101 insn = prog->insnsi; 2102 goto select_insn; 2103 out: 2104 CONT; 2105 } 2106 JMP_JA: 2107 insn += insn->off; 2108 CONT; 2109 JMP32_JA: 2110 insn += insn->imm; 2111 CONT; 2112 JMP_EXIT: 2113 return BPF_R0; 2114 /* JMP */ 2115 #define COND_JMP(SIGN, OPCODE, CMP_OP) \ 2116 JMP_##OPCODE##_X: \ 2117 if ((SIGN##64) DST CMP_OP (SIGN##64) SRC) { \ 2118 insn += insn->off; \ 2119 CONT_JMP; \ 2120 } \ 2121 CONT; \ 2122 JMP32_##OPCODE##_X: \ 2123 if ((SIGN##32) DST CMP_OP (SIGN##32) SRC) { \ 2124 insn += insn->off; \ 2125 CONT_JMP; \ 2126 } \ 2127 CONT; \ 2128 JMP_##OPCODE##_K: \ 2129 if ((SIGN##64) DST CMP_OP (SIGN##64) IMM) { \ 2130 insn += insn->off; \ 2131 CONT_JMP; \ 2132 } \ 2133 CONT; \ 2134 JMP32_##OPCODE##_K: \ 2135 if ((SIGN##32) DST CMP_OP (SIGN##32) IMM) { \ 2136 insn += insn->off; \ 2137 CONT_JMP; \ 2138 } \ 2139 CONT; 2140 COND_JMP(u, JEQ, ==) 2141 COND_JMP(u, JNE, !=) 2142 COND_JMP(u, JGT, >) 2143 COND_JMP(u, JLT, <) 2144 COND_JMP(u, JGE, >=) 2145 COND_JMP(u, JLE, <=) 2146 COND_JMP(u, JSET, &) 2147 COND_JMP(s, JSGT, >) 2148 COND_JMP(s, JSLT, <) 2149 COND_JMP(s, JSGE, >=) 2150 COND_JMP(s, JSLE, <=) 2151 #undef COND_JMP 2152 /* ST, STX and LDX*/ 2153 ST_NOSPEC: 2154 /* Speculation barrier for mitigating Speculative Store Bypass, 2155 * Bounds-Check Bypass and Type Confusion. In case of arm64, we 2156 * rely on the firmware mitigation as controlled via the ssbd 2157 * kernel parameter. Whenever the mitigation is enabled, it 2158 * works for all of the kernel code with no need to provide any 2159 * additional instructions here. In case of x86, we use 'lfence' 2160 * insn for mitigation. We reuse preexisting logic from Spectre 2161 * v1 mitigation that happens to produce the required code on 2162 * x86 for v4 as well. 2163 */ 2164 barrier_nospec(); 2165 CONT; 2166 #define LDST(SIZEOP, SIZE) \ 2167 STX_MEM_##SIZEOP: \ 2168 *(SIZE *)(unsigned long) (DST + insn->off) = SRC; \ 2169 CONT; \ 2170 ST_MEM_##SIZEOP: \ 2171 *(SIZE *)(unsigned long) (DST + insn->off) = IMM; \ 2172 CONT; \ 2173 LDX_MEM_##SIZEOP: \ 2174 DST = *(SIZE *)(unsigned long) (SRC + insn->off); \ 2175 CONT; \ 2176 LDX_PROBE_MEM_##SIZEOP: \ 2177 bpf_probe_read_kernel_common(&DST, sizeof(SIZE), \ 2178 (const void *)(long) (SRC + insn->off)); \ 2179 DST = *((SIZE *)&DST); \ 2180 CONT; 2181 2182 LDST(B, u8) 2183 LDST(H, u16) 2184 LDST(W, u32) 2185 LDST(DW, u64) 2186 #undef LDST 2187 2188 #define LDSX(SIZEOP, SIZE) \ 2189 LDX_MEMSX_##SIZEOP: \ 2190 DST = *(SIZE *)(unsigned long) (SRC + insn->off); \ 2191 CONT; \ 2192 LDX_PROBE_MEMSX_##SIZEOP: \ 2193 bpf_probe_read_kernel_common(&DST, sizeof(SIZE), \ 2194 (const void *)(long) (SRC + insn->off)); \ 2195 DST = *((SIZE *)&DST); \ 2196 CONT; 2197 2198 LDSX(B, s8) 2199 LDSX(H, s16) 2200 LDSX(W, s32) 2201 #undef LDSX 2202 2203 #define ATOMIC_ALU_OP(BOP, KOP) \ 2204 case BOP: \ 2205 if (BPF_SIZE(insn->code) == BPF_W) \ 2206 atomic_##KOP((u32) SRC, (atomic_t *)(unsigned long) \ 2207 (DST + insn->off)); \ 2208 else if (BPF_SIZE(insn->code) == BPF_DW) \ 2209 atomic64_##KOP((u64) SRC, (atomic64_t *)(unsigned long) \ 2210 (DST + insn->off)); \ 2211 else \ 2212 goto default_label; \ 2213 break; \ 2214 case BOP | BPF_FETCH: \ 2215 if (BPF_SIZE(insn->code) == BPF_W) \ 2216 SRC = (u32) atomic_fetch_##KOP( \ 2217 (u32) SRC, \ 2218 (atomic_t *)(unsigned long) (DST + insn->off)); \ 2219 else if (BPF_SIZE(insn->code) == BPF_DW) \ 2220 SRC = (u64) atomic64_fetch_##KOP( \ 2221 (u64) SRC, \ 2222 (atomic64_t *)(unsigned long) (DST + insn->off)); \ 2223 else \ 2224 goto default_label; \ 2225 break; 2226 2227 STX_ATOMIC_DW: 2228 STX_ATOMIC_W: 2229 STX_ATOMIC_H: 2230 STX_ATOMIC_B: 2231 switch (IMM) { 2232 /* Atomic read-modify-write instructions support only W and DW 2233 * size modifiers. 2234 */ 2235 ATOMIC_ALU_OP(BPF_ADD, add) 2236 ATOMIC_ALU_OP(BPF_AND, and) 2237 ATOMIC_ALU_OP(BPF_OR, or) 2238 ATOMIC_ALU_OP(BPF_XOR, xor) 2239 #undef ATOMIC_ALU_OP 2240 2241 case BPF_XCHG: 2242 if (BPF_SIZE(insn->code) == BPF_W) 2243 SRC = (u32) atomic_xchg( 2244 (atomic_t *)(unsigned long) (DST + insn->off), 2245 (u32) SRC); 2246 else if (BPF_SIZE(insn->code) == BPF_DW) 2247 SRC = (u64) atomic64_xchg( 2248 (atomic64_t *)(unsigned long) (DST + insn->off), 2249 (u64) SRC); 2250 else 2251 goto default_label; 2252 break; 2253 case BPF_CMPXCHG: 2254 if (BPF_SIZE(insn->code) == BPF_W) 2255 BPF_R0 = (u32) atomic_cmpxchg( 2256 (atomic_t *)(unsigned long) (DST + insn->off), 2257 (u32) BPF_R0, (u32) SRC); 2258 else if (BPF_SIZE(insn->code) == BPF_DW) 2259 BPF_R0 = (u64) atomic64_cmpxchg( 2260 (atomic64_t *)(unsigned long) (DST + insn->off), 2261 (u64) BPF_R0, (u64) SRC); 2262 else 2263 goto default_label; 2264 break; 2265 /* Atomic load and store instructions support all size 2266 * modifiers. 2267 */ 2268 case BPF_LOAD_ACQ: 2269 switch (BPF_SIZE(insn->code)) { 2270 #define LOAD_ACQUIRE(SIZEOP, SIZE) \ 2271 case BPF_##SIZEOP: \ 2272 DST = (SIZE)smp_load_acquire( \ 2273 (SIZE *)(unsigned long)(SRC + insn->off)); \ 2274 break; 2275 LOAD_ACQUIRE(B, u8) 2276 LOAD_ACQUIRE(H, u16) 2277 LOAD_ACQUIRE(W, u32) 2278 #ifdef CONFIG_64BIT 2279 LOAD_ACQUIRE(DW, u64) 2280 #endif 2281 #undef LOAD_ACQUIRE 2282 default: 2283 goto default_label; 2284 } 2285 break; 2286 case BPF_STORE_REL: 2287 switch (BPF_SIZE(insn->code)) { 2288 #define STORE_RELEASE(SIZEOP, SIZE) \ 2289 case BPF_##SIZEOP: \ 2290 smp_store_release( \ 2291 (SIZE *)(unsigned long)(DST + insn->off), (SIZE)SRC); \ 2292 break; 2293 STORE_RELEASE(B, u8) 2294 STORE_RELEASE(H, u16) 2295 STORE_RELEASE(W, u32) 2296 #ifdef CONFIG_64BIT 2297 STORE_RELEASE(DW, u64) 2298 #endif 2299 #undef STORE_RELEASE 2300 default: 2301 goto default_label; 2302 } 2303 break; 2304 2305 default: 2306 goto default_label; 2307 } 2308 CONT; 2309 2310 default_label: 2311 /* If we ever reach this, we have a bug somewhere. Die hard here 2312 * instead of just returning 0; we could be somewhere in a subprog, 2313 * so execution could continue otherwise which we do /not/ want. 2314 * 2315 * Note, verifier whitelists all opcodes in bpf_opcode_in_insntable(). 2316 */ 2317 pr_warn("BPF interpreter: unknown opcode %02x (imm: 0x%x)\n", 2318 insn->code, insn->imm); 2319 BUG_ON(1); 2320 return 0; 2321 } 2322 2323 #define PROG_NAME(stack_size) __bpf_prog_run##stack_size 2324 #define DEFINE_BPF_PROG_RUN(stack_size) \ 2325 static unsigned int PROG_NAME(stack_size)(const void *ctx, const struct bpf_insn *insn) \ 2326 { \ 2327 u64 stack[stack_size / sizeof(u64)]; \ 2328 u64 regs[MAX_BPF_EXT_REG] = {}; \ 2329 \ 2330 kmsan_unpoison_memory(stack, sizeof(stack)); \ 2331 FP = (u64) (unsigned long) &stack[ARRAY_SIZE(stack)]; \ 2332 ARG1 = (u64) (unsigned long) ctx; \ 2333 return ___bpf_prog_run(regs, insn); \ 2334 } 2335 2336 #define PROG_NAME_ARGS(stack_size) __bpf_prog_run_args##stack_size 2337 #define DEFINE_BPF_PROG_RUN_ARGS(stack_size) \ 2338 static u64 PROG_NAME_ARGS(stack_size)(u64 r1, u64 r2, u64 r3, u64 r4, u64 r5, \ 2339 const struct bpf_insn *insn) \ 2340 { \ 2341 u64 stack[stack_size / sizeof(u64)]; \ 2342 u64 regs[MAX_BPF_EXT_REG]; \ 2343 \ 2344 kmsan_unpoison_memory(stack, sizeof(stack)); \ 2345 FP = (u64) (unsigned long) &stack[ARRAY_SIZE(stack)]; \ 2346 BPF_R1 = r1; \ 2347 BPF_R2 = r2; \ 2348 BPF_R3 = r3; \ 2349 BPF_R4 = r4; \ 2350 BPF_R5 = r5; \ 2351 return ___bpf_prog_run(regs, insn); \ 2352 } 2353 2354 #define EVAL1(FN, X) FN(X) 2355 #define EVAL2(FN, X, Y...) FN(X) EVAL1(FN, Y) 2356 #define EVAL3(FN, X, Y...) FN(X) EVAL2(FN, Y) 2357 #define EVAL4(FN, X, Y...) FN(X) EVAL3(FN, Y) 2358 #define EVAL5(FN, X, Y...) FN(X) EVAL4(FN, Y) 2359 #define EVAL6(FN, X, Y...) FN(X) EVAL5(FN, Y) 2360 2361 EVAL6(DEFINE_BPF_PROG_RUN, 32, 64, 96, 128, 160, 192); 2362 EVAL6(DEFINE_BPF_PROG_RUN, 224, 256, 288, 320, 352, 384); 2363 EVAL4(DEFINE_BPF_PROG_RUN, 416, 448, 480, 512); 2364 2365 EVAL6(DEFINE_BPF_PROG_RUN_ARGS, 32, 64, 96, 128, 160, 192); 2366 EVAL6(DEFINE_BPF_PROG_RUN_ARGS, 224, 256, 288, 320, 352, 384); 2367 EVAL4(DEFINE_BPF_PROG_RUN_ARGS, 416, 448, 480, 512); 2368 2369 #define PROG_NAME_LIST(stack_size) PROG_NAME(stack_size), 2370 2371 static unsigned int (*interpreters[])(const void *ctx, 2372 const struct bpf_insn *insn) = { 2373 EVAL6(PROG_NAME_LIST, 32, 64, 96, 128, 160, 192) 2374 EVAL6(PROG_NAME_LIST, 224, 256, 288, 320, 352, 384) 2375 EVAL4(PROG_NAME_LIST, 416, 448, 480, 512) 2376 }; 2377 #undef PROG_NAME_LIST 2378 #define PROG_NAME_LIST(stack_size) PROG_NAME_ARGS(stack_size), 2379 static __maybe_unused 2380 u64 (*interpreters_args[])(u64 r1, u64 r2, u64 r3, u64 r4, u64 r5, 2381 const struct bpf_insn *insn) = { 2382 EVAL6(PROG_NAME_LIST, 32, 64, 96, 128, 160, 192) 2383 EVAL6(PROG_NAME_LIST, 224, 256, 288, 320, 352, 384) 2384 EVAL4(PROG_NAME_LIST, 416, 448, 480, 512) 2385 }; 2386 #undef PROG_NAME_LIST 2387 2388 #ifdef CONFIG_BPF_SYSCALL 2389 void bpf_patch_call_args(struct bpf_insn *insn, u32 stack_depth) 2390 { 2391 stack_depth = max_t(u32, stack_depth, 1); 2392 insn->off = (s16) insn->imm; 2393 insn->imm = interpreters_args[(round_up(stack_depth, 32) / 32) - 1] - 2394 __bpf_call_base_args; 2395 insn->code = BPF_JMP | BPF_CALL_ARGS; 2396 } 2397 #endif 2398 #endif 2399 2400 static unsigned int __bpf_prog_ret0_warn(const void *ctx, 2401 const struct bpf_insn *insn) 2402 { 2403 /* If this handler ever gets executed, then BPF_JIT_ALWAYS_ON 2404 * is not working properly, so warn about it! 2405 */ 2406 WARN_ON_ONCE(1); 2407 return 0; 2408 } 2409 2410 static bool __bpf_prog_map_compatible(struct bpf_map *map, 2411 const struct bpf_prog *fp) 2412 { 2413 enum bpf_prog_type prog_type = resolve_prog_type(fp); 2414 struct bpf_prog_aux *aux = fp->aux; 2415 enum bpf_cgroup_storage_type i; 2416 bool ret = false; 2417 u64 cookie; 2418 2419 if (fp->kprobe_override) 2420 return ret; 2421 2422 spin_lock(&map->owner_lock); 2423 /* There's no owner yet where we could check for compatibility. */ 2424 if (!map->owner) { 2425 map->owner = bpf_map_owner_alloc(map); 2426 if (!map->owner) 2427 goto err; 2428 map->owner->type = prog_type; 2429 map->owner->jited = fp->jited; 2430 map->owner->xdp_has_frags = aux->xdp_has_frags; 2431 map->owner->sleepable = fp->sleepable; 2432 map->owner->expected_attach_type = fp->expected_attach_type; 2433 map->owner->attach_func_proto = aux->attach_func_proto; 2434 for_each_cgroup_storage_type(i) { 2435 map->owner->storage_cookie[i] = 2436 aux->cgroup_storage[i] ? 2437 aux->cgroup_storage[i]->cookie : 0; 2438 } 2439 ret = true; 2440 } else { 2441 ret = map->owner->type == prog_type && 2442 map->owner->jited == fp->jited && 2443 map->owner->xdp_has_frags == aux->xdp_has_frags && 2444 map->owner->sleepable == fp->sleepable; 2445 if (ret && 2446 map->map_type == BPF_MAP_TYPE_PROG_ARRAY && 2447 map->owner->expected_attach_type != fp->expected_attach_type) 2448 ret = false; 2449 for_each_cgroup_storage_type(i) { 2450 if (!ret) 2451 break; 2452 cookie = aux->cgroup_storage[i] ? 2453 aux->cgroup_storage[i]->cookie : 0; 2454 ret = map->owner->storage_cookie[i] == cookie || 2455 !cookie; 2456 } 2457 if (ret && 2458 map->owner->attach_func_proto != aux->attach_func_proto) { 2459 switch (prog_type) { 2460 case BPF_PROG_TYPE_TRACING: 2461 case BPF_PROG_TYPE_LSM: 2462 case BPF_PROG_TYPE_EXT: 2463 case BPF_PROG_TYPE_STRUCT_OPS: 2464 ret = false; 2465 break; 2466 default: 2467 break; 2468 } 2469 } 2470 } 2471 err: 2472 spin_unlock(&map->owner_lock); 2473 return ret; 2474 } 2475 2476 bool bpf_prog_map_compatible(struct bpf_map *map, const struct bpf_prog *fp) 2477 { 2478 /* XDP programs inserted into maps are not guaranteed to run on 2479 * a particular netdev (and can run outside driver context entirely 2480 * in the case of devmap and cpumap). Until device checks 2481 * are implemented, prohibit adding dev-bound programs to program maps. 2482 */ 2483 if (bpf_prog_is_dev_bound(fp->aux)) 2484 return false; 2485 2486 return __bpf_prog_map_compatible(map, fp); 2487 } 2488 2489 static int bpf_check_tail_call(const struct bpf_prog *fp) 2490 { 2491 struct bpf_prog_aux *aux = fp->aux; 2492 int i, ret = 0; 2493 2494 mutex_lock(&aux->used_maps_mutex); 2495 for (i = 0; i < aux->used_map_cnt; i++) { 2496 struct bpf_map *map = aux->used_maps[i]; 2497 2498 if (!map_type_contains_progs(map)) 2499 continue; 2500 2501 if (!__bpf_prog_map_compatible(map, fp)) { 2502 ret = -EINVAL; 2503 goto out; 2504 } 2505 } 2506 2507 out: 2508 mutex_unlock(&aux->used_maps_mutex); 2509 return ret; 2510 } 2511 2512 static bool bpf_prog_select_interpreter(struct bpf_prog *fp) 2513 { 2514 bool select_interpreter = false; 2515 #ifndef CONFIG_BPF_JIT_ALWAYS_ON 2516 u32 stack_depth = max_t(u32, fp->aux->stack_depth, 1); 2517 u32 idx = (round_up(stack_depth, 32) / 32) - 1; 2518 2519 /* may_goto may cause stack size > 512, leading to idx out-of-bounds. 2520 * But for non-JITed programs, we don't need bpf_func, so no bounds 2521 * check needed. 2522 */ 2523 if (idx < ARRAY_SIZE(interpreters)) { 2524 fp->bpf_func = interpreters[idx]; 2525 select_interpreter = true; 2526 } else { 2527 fp->bpf_func = __bpf_prog_ret0_warn; 2528 } 2529 #else 2530 fp->bpf_func = __bpf_prog_ret0_warn; 2531 #endif 2532 return select_interpreter; 2533 } 2534 2535 /** 2536 * bpf_prog_select_runtime - select exec runtime for BPF program 2537 * @fp: bpf_prog populated with BPF program 2538 * @err: pointer to error variable 2539 * 2540 * Try to JIT eBPF program, if JIT is not available, use interpreter. 2541 * The BPF program will be executed via bpf_prog_run() function. 2542 * 2543 * Return: the &fp argument along with &err set to 0 for success or 2544 * a negative errno code on failure 2545 */ 2546 struct bpf_prog *bpf_prog_select_runtime(struct bpf_prog *fp, int *err) 2547 { 2548 /* In case of BPF to BPF calls, verifier did all the prep 2549 * work with regards to JITing, etc. 2550 */ 2551 bool jit_needed = false; 2552 2553 if (fp->bpf_func) 2554 goto finalize; 2555 2556 if (IS_ENABLED(CONFIG_BPF_JIT_ALWAYS_ON) || 2557 bpf_prog_has_kfunc_call(fp)) 2558 jit_needed = true; 2559 2560 if (!bpf_prog_select_interpreter(fp)) 2561 jit_needed = true; 2562 2563 /* eBPF JITs can rewrite the program in case constant 2564 * blinding is active. However, in case of error during 2565 * blinding, bpf_int_jit_compile() must always return a 2566 * valid program, which in this case would simply not 2567 * be JITed, but falls back to the interpreter. 2568 */ 2569 if (!bpf_prog_is_offloaded(fp->aux)) { 2570 *err = bpf_prog_alloc_jited_linfo(fp); 2571 if (*err) 2572 return fp; 2573 2574 fp = bpf_int_jit_compile(fp); 2575 bpf_prog_jit_attempt_done(fp); 2576 if (!fp->jited && jit_needed) { 2577 *err = -ENOTSUPP; 2578 return fp; 2579 } 2580 } else { 2581 *err = bpf_prog_offload_compile(fp); 2582 if (*err) 2583 return fp; 2584 } 2585 2586 finalize: 2587 *err = bpf_prog_lock_ro(fp); 2588 if (*err) 2589 return fp; 2590 2591 /* The tail call compatibility check can only be done at 2592 * this late stage as we need to determine, if we deal 2593 * with JITed or non JITed program concatenations and not 2594 * all eBPF JITs might immediately support all features. 2595 */ 2596 *err = bpf_check_tail_call(fp); 2597 2598 return fp; 2599 } 2600 EXPORT_SYMBOL_GPL(bpf_prog_select_runtime); 2601 2602 static unsigned int __bpf_prog_ret1(const void *ctx, 2603 const struct bpf_insn *insn) 2604 { 2605 return 1; 2606 } 2607 2608 static struct bpf_prog_dummy { 2609 struct bpf_prog prog; 2610 } dummy_bpf_prog = { 2611 .prog = { 2612 .bpf_func = __bpf_prog_ret1, 2613 }, 2614 }; 2615 2616 struct bpf_empty_prog_array bpf_empty_prog_array = { 2617 .null_prog = NULL, 2618 }; 2619 EXPORT_SYMBOL(bpf_empty_prog_array); 2620 2621 struct bpf_prog_array *bpf_prog_array_alloc(u32 prog_cnt, gfp_t flags) 2622 { 2623 struct bpf_prog_array *p; 2624 2625 if (prog_cnt) 2626 p = kzalloc_flex(*p, items, prog_cnt + 1, flags); 2627 else 2628 p = &bpf_empty_prog_array.hdr; 2629 2630 return p; 2631 } 2632 2633 void bpf_prog_array_free(struct bpf_prog_array *progs) 2634 { 2635 if (!progs || progs == &bpf_empty_prog_array.hdr) 2636 return; 2637 kfree_rcu(progs, rcu); 2638 } 2639 2640 static void __bpf_prog_array_free_sleepable_cb(struct rcu_head *rcu) 2641 { 2642 struct bpf_prog_array *progs; 2643 2644 /* If RCU Tasks Trace grace period implies RCU grace period, there is 2645 * no need to call kfree_rcu(), just call kfree() directly. 2646 */ 2647 progs = container_of(rcu, struct bpf_prog_array, rcu); 2648 if (rcu_trace_implies_rcu_gp()) 2649 kfree(progs); 2650 else 2651 kfree_rcu(progs, rcu); 2652 } 2653 2654 void bpf_prog_array_free_sleepable(struct bpf_prog_array *progs) 2655 { 2656 if (!progs || progs == &bpf_empty_prog_array.hdr) 2657 return; 2658 call_rcu_tasks_trace(&progs->rcu, __bpf_prog_array_free_sleepable_cb); 2659 } 2660 2661 int bpf_prog_array_length(struct bpf_prog_array *array) 2662 { 2663 struct bpf_prog_array_item *item; 2664 u32 cnt = 0; 2665 2666 for (item = array->items; item->prog; item++) 2667 if (item->prog != &dummy_bpf_prog.prog) 2668 cnt++; 2669 return cnt; 2670 } 2671 2672 bool bpf_prog_array_is_empty(struct bpf_prog_array *array) 2673 { 2674 struct bpf_prog_array_item *item; 2675 2676 for (item = array->items; item->prog; item++) 2677 if (item->prog != &dummy_bpf_prog.prog) 2678 return false; 2679 return true; 2680 } 2681 2682 static bool bpf_prog_array_copy_core(struct bpf_prog_array *array, 2683 u32 *prog_ids, 2684 u32 request_cnt) 2685 { 2686 struct bpf_prog_array_item *item; 2687 int i = 0; 2688 2689 for (item = array->items; item->prog; item++) { 2690 if (item->prog == &dummy_bpf_prog.prog) 2691 continue; 2692 prog_ids[i] = item->prog->aux->id; 2693 if (++i == request_cnt) { 2694 item++; 2695 break; 2696 } 2697 } 2698 2699 return !!(item->prog); 2700 } 2701 2702 int bpf_prog_array_copy_to_user(struct bpf_prog_array *array, 2703 __u32 __user *prog_ids, u32 cnt) 2704 { 2705 unsigned long err = 0; 2706 bool nospc; 2707 u32 *ids; 2708 2709 /* users of this function are doing: 2710 * cnt = bpf_prog_array_length(); 2711 * if (cnt > 0) 2712 * bpf_prog_array_copy_to_user(..., cnt); 2713 * so below kcalloc doesn't need extra cnt > 0 check. 2714 */ 2715 ids = kcalloc(cnt, sizeof(u32), GFP_USER | __GFP_NOWARN); 2716 if (!ids) 2717 return -ENOMEM; 2718 nospc = bpf_prog_array_copy_core(array, ids, cnt); 2719 err = copy_to_user(prog_ids, ids, cnt * sizeof(u32)); 2720 kfree(ids); 2721 if (err) 2722 return -EFAULT; 2723 if (nospc) 2724 return -ENOSPC; 2725 return 0; 2726 } 2727 2728 void bpf_prog_array_delete_safe(struct bpf_prog_array *array, 2729 struct bpf_prog *old_prog) 2730 { 2731 struct bpf_prog_array_item *item; 2732 2733 for (item = array->items; item->prog; item++) 2734 if (item->prog == old_prog) { 2735 WRITE_ONCE(item->prog, &dummy_bpf_prog.prog); 2736 break; 2737 } 2738 } 2739 2740 /** 2741 * bpf_prog_array_delete_safe_at() - Replaces the program at the given 2742 * index into the program array with 2743 * a dummy no-op program. 2744 * @array: a bpf_prog_array 2745 * @index: the index of the program to replace 2746 * 2747 * Skips over dummy programs, by not counting them, when calculating 2748 * the position of the program to replace. 2749 * 2750 * Return: 2751 * * 0 - Success 2752 * * -EINVAL - Invalid index value. Must be a non-negative integer. 2753 * * -ENOENT - Index out of range 2754 */ 2755 int bpf_prog_array_delete_safe_at(struct bpf_prog_array *array, int index) 2756 { 2757 return bpf_prog_array_update_at(array, index, &dummy_bpf_prog.prog); 2758 } 2759 2760 /** 2761 * bpf_prog_array_update_at() - Updates the program at the given index 2762 * into the program array. 2763 * @array: a bpf_prog_array 2764 * @index: the index of the program to update 2765 * @prog: the program to insert into the array 2766 * 2767 * Skips over dummy programs, by not counting them, when calculating 2768 * the position of the program to update. 2769 * 2770 * Return: 2771 * * 0 - Success 2772 * * -EINVAL - Invalid index value. Must be a non-negative integer. 2773 * * -ENOENT - Index out of range 2774 */ 2775 int bpf_prog_array_update_at(struct bpf_prog_array *array, int index, 2776 struct bpf_prog *prog) 2777 { 2778 struct bpf_prog_array_item *item; 2779 2780 if (unlikely(index < 0)) 2781 return -EINVAL; 2782 2783 for (item = array->items; item->prog; item++) { 2784 if (item->prog == &dummy_bpf_prog.prog) 2785 continue; 2786 if (!index) { 2787 WRITE_ONCE(item->prog, prog); 2788 return 0; 2789 } 2790 index--; 2791 } 2792 return -ENOENT; 2793 } 2794 2795 int bpf_prog_array_copy(struct bpf_prog_array *old_array, 2796 struct bpf_prog *exclude_prog, 2797 struct bpf_prog *include_prog, 2798 u64 bpf_cookie, 2799 struct bpf_prog_array **new_array) 2800 { 2801 int new_prog_cnt, carry_prog_cnt = 0; 2802 struct bpf_prog_array_item *existing, *new; 2803 struct bpf_prog_array *array; 2804 bool found_exclude = false; 2805 2806 /* Figure out how many existing progs we need to carry over to 2807 * the new array. 2808 */ 2809 if (old_array) { 2810 existing = old_array->items; 2811 for (; existing->prog; existing++) { 2812 if (existing->prog == exclude_prog) { 2813 found_exclude = true; 2814 continue; 2815 } 2816 if (existing->prog != &dummy_bpf_prog.prog) 2817 carry_prog_cnt++; 2818 if (existing->prog == include_prog) 2819 return -EEXIST; 2820 } 2821 } 2822 2823 if (exclude_prog && !found_exclude) 2824 return -ENOENT; 2825 2826 /* How many progs (not NULL) will be in the new array? */ 2827 new_prog_cnt = carry_prog_cnt; 2828 if (include_prog) 2829 new_prog_cnt += 1; 2830 2831 /* Do we have any prog (not NULL) in the new array? */ 2832 if (!new_prog_cnt) { 2833 *new_array = NULL; 2834 return 0; 2835 } 2836 2837 /* +1 as the end of prog_array is marked with NULL */ 2838 array = bpf_prog_array_alloc(new_prog_cnt + 1, GFP_KERNEL); 2839 if (!array) 2840 return -ENOMEM; 2841 new = array->items; 2842 2843 /* Fill in the new prog array */ 2844 if (carry_prog_cnt) { 2845 existing = old_array->items; 2846 for (; existing->prog; existing++) { 2847 if (existing->prog == exclude_prog || 2848 existing->prog == &dummy_bpf_prog.prog) 2849 continue; 2850 2851 new->prog = existing->prog; 2852 new->bpf_cookie = existing->bpf_cookie; 2853 new++; 2854 } 2855 } 2856 if (include_prog) { 2857 new->prog = include_prog; 2858 new->bpf_cookie = bpf_cookie; 2859 new++; 2860 } 2861 new->prog = NULL; 2862 *new_array = array; 2863 return 0; 2864 } 2865 2866 int bpf_prog_array_copy_info(struct bpf_prog_array *array, 2867 u32 *prog_ids, u32 request_cnt, 2868 u32 *prog_cnt) 2869 { 2870 u32 cnt = 0; 2871 2872 if (array) 2873 cnt = bpf_prog_array_length(array); 2874 2875 *prog_cnt = cnt; 2876 2877 /* return early if user requested only program count or nothing to copy */ 2878 if (!request_cnt || !cnt) 2879 return 0; 2880 2881 /* this function is called under trace/bpf_trace.c: bpf_event_mutex */ 2882 return bpf_prog_array_copy_core(array, prog_ids, request_cnt) ? -ENOSPC 2883 : 0; 2884 } 2885 2886 void __bpf_free_used_maps(struct bpf_prog_aux *aux, 2887 struct bpf_map **used_maps, u32 len) 2888 { 2889 struct bpf_map *map; 2890 bool sleepable; 2891 u32 i; 2892 2893 sleepable = aux->prog->sleepable; 2894 for (i = 0; i < len; i++) { 2895 map = used_maps[i]; 2896 if (map->ops->map_poke_untrack) 2897 map->ops->map_poke_untrack(map, aux); 2898 if (sleepable) 2899 atomic64_dec(&map->sleepable_refcnt); 2900 bpf_map_put(map); 2901 } 2902 } 2903 2904 static void bpf_free_used_maps(struct bpf_prog_aux *aux) 2905 { 2906 __bpf_free_used_maps(aux, aux->used_maps, aux->used_map_cnt); 2907 kfree(aux->used_maps); 2908 } 2909 2910 void __bpf_free_used_btfs(struct btf_mod_pair *used_btfs, u32 len) 2911 { 2912 #ifdef CONFIG_BPF_SYSCALL 2913 struct btf_mod_pair *btf_mod; 2914 u32 i; 2915 2916 for (i = 0; i < len; i++) { 2917 btf_mod = &used_btfs[i]; 2918 if (btf_mod->module) 2919 module_put(btf_mod->module); 2920 btf_put(btf_mod->btf); 2921 } 2922 #endif 2923 } 2924 2925 static void bpf_free_used_btfs(struct bpf_prog_aux *aux) 2926 { 2927 __bpf_free_used_btfs(aux->used_btfs, aux->used_btf_cnt); 2928 kfree(aux->used_btfs); 2929 } 2930 2931 static void bpf_prog_free_deferred(struct work_struct *work) 2932 { 2933 struct bpf_prog_aux *aux; 2934 int i; 2935 2936 aux = container_of(work, struct bpf_prog_aux, work); 2937 #ifdef CONFIG_BPF_SYSCALL 2938 bpf_free_kfunc_btf_tab(aux->kfunc_btf_tab); 2939 bpf_prog_stream_free(aux->prog); 2940 #endif 2941 #ifdef CONFIG_CGROUP_BPF 2942 if (aux->cgroup_atype != CGROUP_BPF_ATTACH_TYPE_INVALID) 2943 bpf_cgroup_atype_put(aux->cgroup_atype); 2944 #endif 2945 bpf_free_used_maps(aux); 2946 bpf_free_used_btfs(aux); 2947 bpf_prog_disassoc_struct_ops(aux->prog); 2948 if (bpf_prog_is_dev_bound(aux)) 2949 bpf_prog_dev_bound_destroy(aux->prog); 2950 #ifdef CONFIG_PERF_EVENTS 2951 if (aux->prog->has_callchain_buf) 2952 put_callchain_buffers(); 2953 #endif 2954 if (aux->dst_trampoline) 2955 bpf_trampoline_put(aux->dst_trampoline); 2956 for (i = 0; i < aux->real_func_cnt; i++) { 2957 /* We can just unlink the subprog poke descriptor table as 2958 * it was originally linked to the main program and is also 2959 * released along with it. 2960 */ 2961 aux->func[i]->aux->poke_tab = NULL; 2962 bpf_jit_free(aux->func[i]); 2963 } 2964 if (aux->real_func_cnt) { 2965 kfree(aux->func); 2966 bpf_prog_unlock_free(aux->prog); 2967 } else { 2968 bpf_jit_free(aux->prog); 2969 } 2970 } 2971 2972 void bpf_prog_free(struct bpf_prog *fp) 2973 { 2974 struct bpf_prog_aux *aux = fp->aux; 2975 2976 if (aux->dst_prog) 2977 bpf_prog_put(aux->dst_prog); 2978 bpf_token_put(aux->token); 2979 INIT_WORK(&aux->work, bpf_prog_free_deferred); 2980 schedule_work(&aux->work); 2981 } 2982 EXPORT_SYMBOL_GPL(bpf_prog_free); 2983 2984 /* RNG for unprivileged user space with separated state from prandom_u32(). */ 2985 static DEFINE_PER_CPU(struct rnd_state, bpf_user_rnd_state); 2986 2987 void bpf_user_rnd_init_once(void) 2988 { 2989 prandom_init_once(&bpf_user_rnd_state); 2990 } 2991 2992 BPF_CALL_0(bpf_user_rnd_u32) 2993 { 2994 /* Should someone ever have the rather unwise idea to use some 2995 * of the registers passed into this function, then note that 2996 * this function is called from native eBPF and classic-to-eBPF 2997 * transformations. Register assignments from both sides are 2998 * different, f.e. classic always sets fn(ctx, A, X) here. 2999 */ 3000 struct rnd_state *state; 3001 u32 res; 3002 3003 state = &get_cpu_var(bpf_user_rnd_state); 3004 res = prandom_u32_state(state); 3005 put_cpu_var(bpf_user_rnd_state); 3006 3007 return res; 3008 } 3009 3010 BPF_CALL_0(bpf_get_raw_cpu_id) 3011 { 3012 return raw_smp_processor_id(); 3013 } 3014 3015 /* Weak definitions of helper functions in case we don't have bpf syscall. */ 3016 const struct bpf_func_proto bpf_map_lookup_elem_proto __weak; 3017 const struct bpf_func_proto bpf_map_update_elem_proto __weak; 3018 const struct bpf_func_proto bpf_map_delete_elem_proto __weak; 3019 const struct bpf_func_proto bpf_map_push_elem_proto __weak; 3020 const struct bpf_func_proto bpf_map_pop_elem_proto __weak; 3021 const struct bpf_func_proto bpf_map_peek_elem_proto __weak; 3022 const struct bpf_func_proto bpf_map_lookup_percpu_elem_proto __weak; 3023 const struct bpf_func_proto bpf_spin_lock_proto __weak; 3024 const struct bpf_func_proto bpf_spin_unlock_proto __weak; 3025 const struct bpf_func_proto bpf_jiffies64_proto __weak; 3026 3027 const struct bpf_func_proto bpf_get_prandom_u32_proto __weak; 3028 const struct bpf_func_proto bpf_get_smp_processor_id_proto __weak; 3029 const struct bpf_func_proto bpf_get_numa_node_id_proto __weak; 3030 const struct bpf_func_proto bpf_ktime_get_ns_proto __weak; 3031 const struct bpf_func_proto bpf_ktime_get_boot_ns_proto __weak; 3032 const struct bpf_func_proto bpf_ktime_get_coarse_ns_proto __weak; 3033 const struct bpf_func_proto bpf_ktime_get_tai_ns_proto __weak; 3034 3035 const struct bpf_func_proto bpf_get_current_pid_tgid_proto __weak; 3036 const struct bpf_func_proto bpf_get_current_uid_gid_proto __weak; 3037 const struct bpf_func_proto bpf_get_current_comm_proto __weak; 3038 const struct bpf_func_proto bpf_get_current_cgroup_id_proto __weak; 3039 const struct bpf_func_proto bpf_get_current_ancestor_cgroup_id_proto __weak; 3040 const struct bpf_func_proto bpf_get_local_storage_proto __weak; 3041 const struct bpf_func_proto bpf_get_ns_current_pid_tgid_proto __weak; 3042 const struct bpf_func_proto bpf_snprintf_btf_proto __weak; 3043 const struct bpf_func_proto bpf_seq_printf_btf_proto __weak; 3044 const struct bpf_func_proto bpf_set_retval_proto __weak; 3045 const struct bpf_func_proto bpf_get_retval_proto __weak; 3046 3047 const struct bpf_func_proto * __weak bpf_get_trace_printk_proto(void) 3048 { 3049 return NULL; 3050 } 3051 3052 const struct bpf_func_proto * __weak bpf_get_trace_vprintk_proto(void) 3053 { 3054 return NULL; 3055 } 3056 3057 const struct bpf_func_proto * __weak bpf_get_perf_event_read_value_proto(void) 3058 { 3059 return NULL; 3060 } 3061 3062 u64 __weak 3063 bpf_event_output(struct bpf_map *map, u64 flags, void *meta, u64 meta_size, 3064 void *ctx, u64 ctx_size, bpf_ctx_copy_t ctx_copy) 3065 { 3066 return -ENOTSUPP; 3067 } 3068 EXPORT_SYMBOL_GPL(bpf_event_output); 3069 3070 /* Always built-in helper functions. */ 3071 const struct bpf_func_proto bpf_tail_call_proto = { 3072 /* func is unused for tail_call, we set it to pass the 3073 * get_helper_proto check 3074 */ 3075 .func = BPF_PTR_POISON, 3076 .gpl_only = false, 3077 .ret_type = RET_VOID, 3078 .arg1_type = ARG_PTR_TO_CTX, 3079 .arg2_type = ARG_CONST_MAP_PTR, 3080 .arg3_type = ARG_ANYTHING, 3081 }; 3082 3083 /* Stub for JITs that only support cBPF. eBPF programs are interpreted. 3084 * It is encouraged to implement bpf_int_jit_compile() instead, so that 3085 * eBPF and implicitly also cBPF can get JITed! 3086 */ 3087 struct bpf_prog * __weak bpf_int_jit_compile(struct bpf_prog *prog) 3088 { 3089 return prog; 3090 } 3091 3092 /* Stub for JITs that support eBPF. All cBPF code gets transformed into 3093 * eBPF by the kernel and is later compiled by bpf_int_jit_compile(). 3094 */ 3095 void __weak bpf_jit_compile(struct bpf_prog *prog) 3096 { 3097 } 3098 3099 bool __weak bpf_helper_changes_pkt_data(enum bpf_func_id func_id) 3100 { 3101 return false; 3102 } 3103 3104 /* Return TRUE if the JIT backend wants verifier to enable sub-register usage 3105 * analysis code and wants explicit zero extension inserted by verifier. 3106 * Otherwise, return FALSE. 3107 * 3108 * The verifier inserts an explicit zero extension after BPF_CMPXCHGs even if 3109 * you don't override this. JITs that don't want these extra insns can detect 3110 * them using insn_is_zext. 3111 */ 3112 bool __weak bpf_jit_needs_zext(void) 3113 { 3114 return false; 3115 } 3116 3117 /* By default, enable the verifier's mitigations against Spectre v1 and v4 for 3118 * all archs. The value returned must not change at runtime as there is 3119 * currently no support for reloading programs that were loaded without 3120 * mitigations. 3121 */ 3122 bool __weak bpf_jit_bypass_spec_v1(void) 3123 { 3124 return false; 3125 } 3126 3127 bool __weak bpf_jit_bypass_spec_v4(void) 3128 { 3129 return false; 3130 } 3131 3132 /* Return true if the JIT inlines the call to the helper corresponding to 3133 * the imm. 3134 * 3135 * The verifier will not patch the insn->imm for the call to the helper if 3136 * this returns true. 3137 */ 3138 bool __weak bpf_jit_inlines_helper_call(s32 imm) 3139 { 3140 return false; 3141 } 3142 3143 /* Return TRUE if the JIT backend supports mixing bpf2bpf and tailcalls. */ 3144 bool __weak bpf_jit_supports_subprog_tailcalls(void) 3145 { 3146 return false; 3147 } 3148 3149 bool __weak bpf_jit_supports_percpu_insn(void) 3150 { 3151 return false; 3152 } 3153 3154 bool __weak bpf_jit_supports_kfunc_call(void) 3155 { 3156 return false; 3157 } 3158 3159 bool __weak bpf_jit_supports_far_kfunc_call(void) 3160 { 3161 return false; 3162 } 3163 3164 bool __weak bpf_jit_supports_arena(void) 3165 { 3166 return false; 3167 } 3168 3169 bool __weak bpf_jit_supports_insn(struct bpf_insn *insn, bool in_arena) 3170 { 3171 return false; 3172 } 3173 3174 bool __weak bpf_jit_supports_fsession(void) 3175 { 3176 return false; 3177 } 3178 3179 u64 __weak bpf_arch_uaddress_limit(void) 3180 { 3181 #if defined(CONFIG_64BIT) && defined(CONFIG_ARCH_HAS_NON_OVERLAPPING_ADDRESS_SPACE) 3182 return TASK_SIZE; 3183 #else 3184 return 0; 3185 #endif 3186 } 3187 3188 /* Return TRUE if the JIT backend satisfies the following two conditions: 3189 * 1) JIT backend supports atomic_xchg() on pointer-sized words. 3190 * 2) Under the specific arch, the implementation of xchg() is the same 3191 * as atomic_xchg() on pointer-sized words. 3192 */ 3193 bool __weak bpf_jit_supports_ptr_xchg(void) 3194 { 3195 return false; 3196 } 3197 3198 /* To execute LD_ABS/LD_IND instructions __bpf_prog_run() may call 3199 * skb_copy_bits(), so provide a weak definition of it for NET-less config. 3200 */ 3201 int __weak skb_copy_bits(const struct sk_buff *skb, int offset, void *to, 3202 int len) 3203 { 3204 return -EFAULT; 3205 } 3206 3207 int __weak bpf_arch_text_poke(void *ip, enum bpf_text_poke_type old_t, 3208 enum bpf_text_poke_type new_t, void *old_addr, 3209 void *new_addr) 3210 { 3211 return -ENOTSUPP; 3212 } 3213 3214 void * __weak bpf_arch_text_copy(void *dst, void *src, size_t len) 3215 { 3216 return ERR_PTR(-ENOTSUPP); 3217 } 3218 3219 int __weak bpf_arch_text_invalidate(void *dst, size_t len) 3220 { 3221 return -ENOTSUPP; 3222 } 3223 3224 bool __weak bpf_jit_supports_exceptions(void) 3225 { 3226 return false; 3227 } 3228 3229 bool __weak bpf_jit_supports_private_stack(void) 3230 { 3231 return false; 3232 } 3233 3234 void __weak arch_bpf_stack_walk(bool (*consume_fn)(void *cookie, u64 ip, u64 sp, u64 bp), void *cookie) 3235 { 3236 } 3237 3238 bool __weak bpf_jit_supports_timed_may_goto(void) 3239 { 3240 return false; 3241 } 3242 3243 u64 __weak arch_bpf_timed_may_goto(void) 3244 { 3245 return 0; 3246 } 3247 3248 static noinline void bpf_prog_report_may_goto_violation(void) 3249 { 3250 #ifdef CONFIG_BPF_SYSCALL 3251 struct bpf_stream_stage ss; 3252 struct bpf_prog *prog; 3253 3254 prog = bpf_prog_find_from_stack(); 3255 if (!prog) 3256 return; 3257 bpf_stream_stage(ss, prog, BPF_STDERR, ({ 3258 bpf_stream_printk(ss, "ERROR: Timeout detected for may_goto instruction\n"); 3259 bpf_stream_dump_stack(ss); 3260 })); 3261 #endif 3262 } 3263 3264 u64 bpf_check_timed_may_goto(struct bpf_timed_may_goto *p) 3265 { 3266 u64 time = ktime_get_mono_fast_ns(); 3267 3268 /* Populate the timestamp for this stack frame, and refresh count. */ 3269 if (!p->timestamp) { 3270 p->timestamp = time; 3271 return BPF_MAX_TIMED_LOOPS; 3272 } 3273 /* Check if we've exhausted our time slice, and zero count. */ 3274 if (unlikely(time - p->timestamp >= (NSEC_PER_SEC / 4))) { 3275 bpf_prog_report_may_goto_violation(); 3276 return 0; 3277 } 3278 /* Refresh the count for the stack frame. */ 3279 return BPF_MAX_TIMED_LOOPS; 3280 } 3281 3282 /* for configs without MMU or 32-bit */ 3283 __weak const struct bpf_map_ops arena_map_ops; 3284 __weak u64 bpf_arena_get_user_vm_start(struct bpf_arena *arena) 3285 { 3286 return 0; 3287 } 3288 __weak u64 bpf_arena_get_kern_vm_start(struct bpf_arena *arena) 3289 { 3290 return 0; 3291 } 3292 3293 #ifdef CONFIG_BPF_SYSCALL 3294 static int __init bpf_global_ma_init(void) 3295 { 3296 int ret; 3297 3298 ret = bpf_mem_alloc_init(&bpf_global_ma, 0, false); 3299 bpf_global_ma_set = !ret; 3300 return ret; 3301 } 3302 late_initcall(bpf_global_ma_init); 3303 #endif 3304 3305 DEFINE_STATIC_KEY_FALSE(bpf_stats_enabled_key); 3306 EXPORT_SYMBOL(bpf_stats_enabled_key); 3307 3308 /* All definitions of tracepoints related to BPF. */ 3309 #define CREATE_TRACE_POINTS 3310 #include <linux/bpf_trace.h> 3311 3312 EXPORT_TRACEPOINT_SYMBOL_GPL(xdp_exception); 3313 EXPORT_TRACEPOINT_SYMBOL_GPL(xdp_bulk_tx); 3314 3315 #ifdef CONFIG_BPF_SYSCALL 3316 3317 int bpf_prog_get_file_line(struct bpf_prog *prog, unsigned long ip, const char **filep, 3318 const char **linep, int *nump) 3319 { 3320 int idx = -1, insn_start, insn_end, len; 3321 struct bpf_line_info *linfo; 3322 void **jited_linfo; 3323 struct btf *btf; 3324 int nr_linfo; 3325 3326 btf = prog->aux->btf; 3327 linfo = prog->aux->linfo; 3328 jited_linfo = prog->aux->jited_linfo; 3329 3330 if (!btf || !linfo || !jited_linfo) 3331 return -EINVAL; 3332 len = prog->aux->func ? prog->aux->func[prog->aux->func_idx]->len : prog->len; 3333 3334 linfo = &prog->aux->linfo[prog->aux->linfo_idx]; 3335 jited_linfo = &prog->aux->jited_linfo[prog->aux->linfo_idx]; 3336 3337 insn_start = linfo[0].insn_off; 3338 insn_end = insn_start + len; 3339 nr_linfo = prog->aux->nr_linfo - prog->aux->linfo_idx; 3340 3341 for (int i = 0; i < nr_linfo && 3342 linfo[i].insn_off >= insn_start && linfo[i].insn_off < insn_end; i++) { 3343 if (jited_linfo[i] >= (void *)ip) 3344 break; 3345 idx = i; 3346 } 3347 3348 if (idx == -1) 3349 return -ENOENT; 3350 3351 /* Get base component of the file path. */ 3352 *filep = btf_name_by_offset(btf, linfo[idx].file_name_off); 3353 *filep = kbasename(*filep); 3354 /* Obtain the source line, and strip whitespace in prefix. */ 3355 *linep = btf_name_by_offset(btf, linfo[idx].line_off); 3356 while (isspace(**linep)) 3357 *linep += 1; 3358 *nump = BPF_LINE_INFO_LINE_NUM(linfo[idx].line_col); 3359 return 0; 3360 } 3361 3362 struct walk_stack_ctx { 3363 struct bpf_prog *prog; 3364 }; 3365 3366 static bool find_from_stack_cb(void *cookie, u64 ip, u64 sp, u64 bp) 3367 { 3368 struct walk_stack_ctx *ctxp = cookie; 3369 struct bpf_prog *prog; 3370 3371 /* 3372 * The RCU read lock is held to safely traverse the latch tree, but we 3373 * don't need its protection when accessing the prog, since it has an 3374 * active stack frame on the current stack trace, and won't disappear. 3375 */ 3376 rcu_read_lock(); 3377 prog = bpf_prog_ksym_find(ip); 3378 rcu_read_unlock(); 3379 if (!prog) 3380 return true; 3381 /* Make sure we return the main prog if we found a subprog */ 3382 ctxp->prog = prog->aux->main_prog_aux->prog; 3383 return false; 3384 } 3385 3386 struct bpf_prog *bpf_prog_find_from_stack(void) 3387 { 3388 struct walk_stack_ctx ctx = {}; 3389 3390 arch_bpf_stack_walk(find_from_stack_cb, &ctx); 3391 return ctx.prog; 3392 } 3393 3394 #endif 3395