kernel/bpf/core.c

   1 /*
   2  * Linux Socket Filter - Kernel level socket filtering
   3  *
   4  * Based on the design of the Berkeley Packet Filter. The new
   5  * internal format has been designed by PLUMgrid:
   6  *
   7  *      Copyright (c) 2011 - 2014 PLUMgrid, http://plumgrid.com
   8  *
   9  * Authors:
  10  *
  11  *      Jay Schulist <jschlst@samba.org>
  12  *      Alexei Starovoitov <ast@plumgrid.com>
  13  *      Daniel Borkmann <dborkman@redhat.com>
  14  *
  15  * This program is free software; you can redistribute it and/or
  16  * modify it under the terms of the GNU General Public License
  17  * as published by the Free Software Foundation; either version
  18  * 2 of the License, or (at your option) any later version.
  19  *
  20  * Andi Kleen - Fix a few bad bugs and races.
  21  * Kris Katterjohn - Added many additional checks in bpf_check_classic()
  22  */
  23
  24 #include <linux/filter.h>
  25 #include <linux/skbuff.h>
  26 #include <linux/vmalloc.h>
  27 #include <linux/random.h>
  28 #include <linux/moduleloader.h>
  29 #include <linux/bpf.h>
  30 #include <linux/frame.h>
  31 #include <linux/rbtree_latch.h>
  32 #include <linux/kallsyms.h>
  33 #include <linux/rcupdate.h>
  34
  35 #include <asm/unaligned.h>
  36
  37 /* Registers */
  38 #define BPF_R0  regs[BPF_REG_0]
  39 #define BPF_R1  regs[BPF_REG_1]
  40 #define BPF_R2  regs[BPF_REG_2]
  41 #define BPF_R3  regs[BPF_REG_3]
  42 #define BPF_R4  regs[BPF_REG_4]
  43 #define BPF_R5  regs[BPF_REG_5]
  44 #define BPF_R6  regs[BPF_REG_6]
  45 #define BPF_R7  regs[BPF_REG_7]
  46 #define BPF_R8  regs[BPF_REG_8]
  47 #define BPF_R9  regs[BPF_REG_9]
  48 #define BPF_R10 regs[BPF_REG_10]
  49
  50 /* Named registers */
  51 #define DST     regs[insn->dst_reg]
  52 #define SRC     regs[insn->src_reg]
  53 #define FP      regs[BPF_REG_FP]
  54 #define ARG1    regs[BPF_REG_ARG1]
  55 #define CTX     regs[BPF_REG_CTX]
  56 #define IMM     insn->imm
  57
  58 /* No hurry in this branch
  59  *
  60  * Exported for the bpf jit load helper.
  61  */
  62 void *bpf_internal_load_pointer_neg_helper(const struct sk_buff *skb, int k, unsigned int size)
  63 {
  64         u8 *ptr = NULL;
  65
  66         if (k >= SKF_NET_OFF)
  67                 ptr = skb_network_header(skb) + k - SKF_NET_OFF;
  68         else if (k >= SKF_LL_OFF)
  69                 ptr = skb_mac_header(skb) + k - SKF_LL_OFF;
  70
  71         if (ptr >= skb->head && ptr + size <= skb_tail_pointer(skb))
  72                 return ptr;
  73
  74         return NULL;
  75 }
  76
  77 struct bpf_prog *bpf_prog_alloc(unsigned int size, gfp_t gfp_extra_flags)
  78 {
  79         gfp_t gfp_flags = GFP_KERNEL | __GFP_HIGHMEM | __GFP_ZERO |
  80                           gfp_extra_flags;
  81         struct bpf_prog_aux *aux;
  82         struct bpf_prog *fp;
  83
  84         size = round_up(size, PAGE_SIZE);
  85         fp = __vmalloc(size, gfp_flags, PAGE_KERNEL);
  86         if (fp == NULL)
  87                 return NULL;
  88
  89         kmemcheck_annotate_bitfield(fp, meta);
  90
  91         aux = kzalloc(sizeof(*aux), GFP_KERNEL | gfp_extra_flags);
  92         if (aux == NULL) {
  93                 vfree(fp);
  94                 return NULL;
  95         }
  96
  97         fp->pages = size / PAGE_SIZE;
  98         fp->aux = aux;
  99         fp->aux->prog = fp;
 100
 101         INIT_LIST_HEAD_RCU(&fp->aux->ksym_lnode);
 102
 103         return fp;
 104 }
 105 EXPORT_SYMBOL_GPL(bpf_prog_alloc);
 106
 107 struct bpf_prog *bpf_prog_realloc(struct bpf_prog *fp_old, unsigned int size,
 108                                   gfp_t gfp_extra_flags)
 109 {
 110         gfp_t gfp_flags = GFP_KERNEL | __GFP_HIGHMEM | __GFP_ZERO |
 111                           gfp_extra_flags;
 112         struct bpf_prog *fp;
 113         u32 pages, delta;
 114         int ret;
 115
 116         BUG_ON(fp_old == NULL);
 117
 118         size = round_up(size, PAGE_SIZE);
 119         pages = size / PAGE_SIZE;
 120         if (pages <= fp_old->pages)
 121                 return fp_old;
 122
 123         delta = pages - fp_old->pages;
 124         ret = __bpf_prog_charge(fp_old->aux->user, delta);
 125         if (ret)
 126                 return NULL;
 127
 128         fp = __vmalloc(size, gfp_flags, PAGE_KERNEL);
 129         if (fp == NULL) {
 130                 __bpf_prog_uncharge(fp_old->aux->user, delta);
 131         } else {
 132                 kmemcheck_annotate_bitfield(fp, meta);
 133
 134                 memcpy(fp, fp_old, fp_old->pages * PAGE_SIZE);
 135                 fp->pages = pages;
 136                 fp->aux->prog = fp;
 137
 138                 /* We keep fp->aux from fp_old around in the new
 139                  * reallocated structure.
 140                  */
 141                 fp_old->aux = NULL;
 142                 __bpf_prog_free(fp_old);
 143         }
 144
 145         return fp;
 146 }
 147
 148 void __bpf_prog_free(struct bpf_prog *fp)
 149 {
 150         kfree(fp->aux);
 151         vfree(fp);
 152 }
 153
 154 int bpf_prog_calc_tag(struct bpf_prog *fp)
 155 {
 156         const u32 bits_offset = SHA_MESSAGE_BYTES - sizeof(__be64);
 157         u32 raw_size = bpf_prog_tag_scratch_size(fp);
 158         u32 digest[SHA_DIGEST_WORDS];
 159         u32 ws[SHA_WORKSPACE_WORDS];
 160         u32 i, bsize, psize, blocks;
 161         struct bpf_insn *dst;
 162         bool was_ld_map;
 163         u8 *raw, *todo;
 164         __be32 *result;
 165         __be64 *bits;
 166
 167         raw = vmalloc(raw_size);
 168         if (!raw)
 169                 return -ENOMEM;
 170
 171         sha_init(digest);
 172         memset(ws, 0, sizeof(ws));
 173
 174         /* We need to take out the map fd for the digest calculation
 175          * since they are unstable from user space side.
 176          */
 177         dst = (void *)raw;
 178         for (i = 0, was_ld_map = false; i < fp->len; i++) {
 179                 dst[i] = fp->insnsi[i];
 180                 if (!was_ld_map &&
 181                     dst[i].code == (BPF_LD | BPF_IMM | BPF_DW) &&
 182                     dst[i].src_reg == BPF_PSEUDO_MAP_FD) {
 183                         was_ld_map = true;
 184                         dst[i].imm = 0;
 185                 } else if (was_ld_map &&
 186                            dst[i].code == 0 &&
 187                            dst[i].dst_reg == 0 &&
 188                            dst[i].src_reg == 0 &&
 189                            dst[i].off == 0) {
 190                         was_ld_map = false;
 191                         dst[i].imm = 0;
 192                 } else {
 193                         was_ld_map = false;
 194                 }
 195         }
 196
 197         psize = bpf_prog_insn_size(fp);
 198         memset(&raw[psize], 0, raw_size - psize);
 199         raw[psize++] = 0x80;
 200
 201         bsize  = round_up(psize, SHA_MESSAGE_BYTES);
 202         blocks = bsize / SHA_MESSAGE_BYTES;
 203         todo   = raw;
 204         if (bsize - psize >= sizeof(__be64)) {
 205                 bits = (__be64 *)(todo + bsize - sizeof(__be64));
 206         } else {
 207                 bits = (__be64 *)(todo + bsize + bits_offset);
 208                 blocks++;
 209         }
 210         *bits = cpu_to_be64((psize - 1) << 3);
 211
 212         while (blocks--) {
 213                 sha_transform(digest, todo, ws);
 214                 todo += SHA_MESSAGE_BYTES;
 215         }
 216
 217         result = (__force __be32 *)digest;
 218         for (i = 0; i < SHA_DIGEST_WORDS; i++)
 219                 result[i] = cpu_to_be32(digest[i]);
 220         memcpy(fp->tag, result, sizeof(fp->tag));
 221
 222         vfree(raw);
 223         return 0;
 224 }
 225
 226 static bool bpf_is_jmp_and_has_target(const struct bpf_insn *insn)
 227 {
 228         return BPF_CLASS(insn->code) == BPF_JMP  &&
 229                /* Call and Exit are both special jumps with no
 230                 * target inside the BPF instruction image.
 231                 */
 232                BPF_OP(insn->code) != BPF_CALL &&
 233                BPF_OP(insn->code) != BPF_EXIT;
 234 }
 235
 236 static void bpf_adj_branches(struct bpf_prog *prog, u32 pos, u32 delta)
 237 {
 238         struct bpf_insn *insn = prog->insnsi;
 239         u32 i, insn_cnt = prog->len;
 240
 241         for (i = 0; i < insn_cnt; i++, insn++) {
 242                 if (!bpf_is_jmp_and_has_target(insn))
 243                         continue;
 244
 245                 /* Adjust offset of jmps if we cross boundaries. */
 246                 if (i < pos && i + insn->off + 1 > pos)
 247                         insn->off += delta;
 248                 else if (i > pos + delta && i + insn->off + 1 <= pos + delta)
 249                         insn->off -= delta;
 250         }
 251 }
 252
 253 struct bpf_prog *bpf_patch_insn_single(struct bpf_prog *prog, u32 off,
 254                                        const struct bpf_insn *patch, u32 len)
 255 {
 256         u32 insn_adj_cnt, insn_rest, insn_delta = len - 1;
 257         struct bpf_prog *prog_adj;
 258
 259         /* Since our patchlet doesn't expand the image, we're done. */
 260         if (insn_delta == 0) {
 261                 memcpy(prog->insnsi + off, patch, sizeof(*patch));
 262                 return prog;
 263         }
 264
 265         insn_adj_cnt = prog->len + insn_delta;
 266
 267         /* Several new instructions need to be inserted. Make room
 268          * for them. Likely, there's no need for a new allocation as
 269          * last page could have large enough tailroom.
 270          */
 271         prog_adj = bpf_prog_realloc(prog, bpf_prog_size(insn_adj_cnt),
 272                                     GFP_USER);
 273         if (!prog_adj)
 274                 return NULL;
 275
 276         prog_adj->len = insn_adj_cnt;
 277
 278         /* Patching happens in 3 steps:
 279          *
 280          * 1) Move over tail of insnsi from next instruction onwards,
 281          *    so we can patch the single target insn with one or more
 282          *    new ones (patching is always from 1 to n insns, n > 0).
 283          * 2) Inject new instructions at the target location.
 284          * 3) Adjust branch offsets if necessary.
 285          */
 286         insn_rest = insn_adj_cnt - off - len;
 287
 288         memmove(prog_adj->insnsi + off + len, prog_adj->insnsi + off + 1,
 289                 sizeof(*patch) * insn_rest);
 290         memcpy(prog_adj->insnsi + off, patch, sizeof(*patch) * len);
 291
 292         bpf_adj_branches(prog_adj, off, insn_delta);
 293
 294         return prog_adj;
 295 }
 296
 297 #ifdef CONFIG_BPF_JIT
 298 static __always_inline void
 299 bpf_get_prog_addr_region(const struct bpf_prog *prog,
 300                          unsigned long *symbol_start,
 301                          unsigned long *symbol_end)
 302 {
 303         const struct bpf_binary_header *hdr = bpf_jit_binary_hdr(prog);
 304         unsigned long addr = (unsigned long)hdr;
 305
 306         WARN_ON_ONCE(!bpf_prog_ebpf_jited(prog));
 307
 308         *symbol_start = addr;
 309         *symbol_end   = addr + hdr->pages * PAGE_SIZE;
 310 }
 311
 312 static void bpf_get_prog_name(const struct bpf_prog *prog, char *sym)
 313 {
 314         BUILD_BUG_ON(sizeof("bpf_prog_") +
 315                      sizeof(prog->tag) * 2 + 1 > KSYM_NAME_LEN);
 316
 317         sym += snprintf(sym, KSYM_NAME_LEN, "bpf_prog_");
 318         sym  = bin2hex(sym, prog->tag, sizeof(prog->tag));
 319         *sym = 0;
 320 }
 321
 322 static __always_inline unsigned long
 323 bpf_get_prog_addr_start(struct latch_tree_node *n)
 324 {
 325         unsigned long symbol_start, symbol_end;
 326         const struct bpf_prog_aux *aux;
 327
 328         aux = container_of(n, struct bpf_prog_aux, ksym_tnode);
 329         bpf_get_prog_addr_region(aux->prog, &symbol_start, &symbol_end);
 330
 331         return symbol_start;
 332 }
 333
 334 static __always_inline bool bpf_tree_less(struct latch_tree_node *a,
 335                                           struct latch_tree_node *b)
 336 {
 337         return bpf_get_prog_addr_start(a) < bpf_get_prog_addr_start(b);
 338 }
 339
 340 static __always_inline int bpf_tree_comp(void *key, struct latch_tree_node *n)
 341 {
 342         unsigned long val = (unsigned long)key;
 343         unsigned long symbol_start, symbol_end;
 344         const struct bpf_prog_aux *aux;
 345
 346         aux = container_of(n, struct bpf_prog_aux, ksym_tnode);
 347         bpf_get_prog_addr_region(aux->prog, &symbol_start, &symbol_end);
 348
 349         if (val < symbol_start)
 350                 return -1;
 351         if (val >= symbol_end)
 352                 return  1;
 353
 354         return 0;
 355 }
 356
 357 static const struct latch_tree_ops bpf_tree_ops = {
 358         .less   = bpf_tree_less,
 359         .comp   = bpf_tree_comp,
 360 };
 361
 362 static DEFINE_SPINLOCK(bpf_lock);
 363 static LIST_HEAD(bpf_kallsyms);
 364 static struct latch_tree_root bpf_tree __cacheline_aligned;
 365
 366 int bpf_jit_kallsyms __read_mostly;
 367
 368 static void bpf_prog_ksym_node_add(struct bpf_prog_aux *aux)
 369 {
 370         WARN_ON_ONCE(!list_empty(&aux->ksym_lnode));
 371         list_add_tail_rcu(&aux->ksym_lnode, &bpf_kallsyms);
 372         latch_tree_insert(&aux->ksym_tnode, &bpf_tree, &bpf_tree_ops);
 373 }
 374
 375 static void bpf_prog_ksym_node_del(struct bpf_prog_aux *aux)
 376 {
 377         if (list_empty(&aux->ksym_lnode))
 378                 return;
 379
 380         latch_tree_erase(&aux->ksym_tnode, &bpf_tree, &bpf_tree_ops);
 381         list_del_rcu(&aux->ksym_lnode);
 382 }
 383
 384 static bool bpf_prog_kallsyms_candidate(const struct bpf_prog *fp)
 385 {
 386         return fp->jited && !bpf_prog_was_classic(fp);
 387 }
 388
 389 static bool bpf_prog_kallsyms_verify_off(const struct bpf_prog *fp)
 390 {
 391         return list_empty(&fp->aux->ksym_lnode) ||
 392                fp->aux->ksym_lnode.prev == LIST_POISON2;
 393 }
 394
 395 void bpf_prog_kallsyms_add(struct bpf_prog *fp)
 396 {
 397         unsigned long flags;
 398
 399         if (!bpf_prog_kallsyms_candidate(fp) ||
 400             !capable(CAP_SYS_ADMIN))
 401                 return;
 402
 403         spin_lock_irqsave(&bpf_lock, flags);
 404         bpf_prog_ksym_node_add(fp->aux);
 405         spin_unlock_irqrestore(&bpf_lock, flags);
 406 }
 407
 408 void bpf_prog_kallsyms_del(struct bpf_prog *fp)
 409 {
 410         unsigned long flags;
 411
 412         if (!bpf_prog_kallsyms_candidate(fp))
 413                 return;
 414
 415         spin_lock_irqsave(&bpf_lock, flags);
 416         bpf_prog_ksym_node_del(fp->aux);
 417         spin_unlock_irqrestore(&bpf_lock, flags);
 418 }
 419
 420 static struct bpf_prog *bpf_prog_kallsyms_find(unsigned long addr)
 421 {
 422         struct latch_tree_node *n;
 423
 424         if (!bpf_jit_kallsyms_enabled())
 425                 return NULL;
 426
 427         n = latch_tree_find((void *)addr, &bpf_tree, &bpf_tree_ops);
 428         return n ?
 429                container_of(n, struct bpf_prog_aux, ksym_tnode)->prog :
 430                NULL;
 431 }
 432
 433 const char *__bpf_address_lookup(unsigned long addr, unsigned long *size,
 434                                  unsigned long *off, char *sym)
 435 {
 436         unsigned long symbol_start, symbol_end;
 437         struct bpf_prog *prog;
 438         char *ret = NULL;
 439
 440         rcu_read_lock();
 441         prog = bpf_prog_kallsyms_find(addr);
 442         if (prog) {
 443                 bpf_get_prog_addr_region(prog, &symbol_start, &symbol_end);
 444                 bpf_get_prog_name(prog, sym);
 445
 446                 ret = sym;
 447                 if (size)
 448                         *size = symbol_end - symbol_start;
 449                 if (off)
 450                         *off  = addr - symbol_start;
 451         }
 452         rcu_read_unlock();
 453
 454         return ret;
 455 }
 456
 457 bool is_bpf_text_address(unsigned long addr)
 458 {
 459         bool ret;
 460
 461         rcu_read_lock();
 462         ret = bpf_prog_kallsyms_find(addr) != NULL;
 463         rcu_read_unlock();
 464
 465         return ret;
 466 }
 467
 468 int bpf_get_kallsym(unsigned int symnum, unsigned long *value, char *type,
 469                     char *sym)
 470 {
 471         unsigned long symbol_start, symbol_end;
 472         struct bpf_prog_aux *aux;
 473         unsigned int it = 0;
 474         int ret = -ERANGE;
 475
 476         if (!bpf_jit_kallsyms_enabled())
 477                 return ret;
 478
 479         rcu_read_lock();
 480         list_for_each_entry_rcu(aux, &bpf_kallsyms, ksym_lnode) {
 481                 if (it++ != symnum)
 482                         continue;
 483
 484                 bpf_get_prog_addr_region(aux->prog, &symbol_start, &symbol_end);
 485                 bpf_get_prog_name(aux->prog, sym);
 486
 487                 *value = symbol_start;
 488                 *type  = BPF_SYM_ELF_TYPE;
 489
 490                 ret = 0;
 491                 break;
 492         }
 493         rcu_read_unlock();
 494
 495         return ret;
 496 }
 497
 498 struct bpf_binary_header *
 499 bpf_jit_binary_alloc(unsigned int proglen, u8 **image_ptr,
 500                      unsigned int alignment,
 501                      bpf_jit_fill_hole_t bpf_fill_ill_insns)
 502 {
 503         struct bpf_binary_header *hdr;
 504         unsigned int size, hole, start;
 505
 506         /* Most of BPF filters are really small, but if some of them
 507          * fill a page, allow at least 128 extra bytes to insert a
 508          * random section of illegal instructions.
 509          */
 510         size = round_up(proglen + sizeof(*hdr) + 128, PAGE_SIZE);
 511         hdr = module_alloc(size);
 512         if (hdr == NULL)
 513                 return NULL;
 514
 515         /* Fill space with illegal/arch-dep instructions. */
 516         bpf_fill_ill_insns(hdr, size);
 517
 518         hdr->pages = size / PAGE_SIZE;
 519         hole = min_t(unsigned int, size - (proglen + sizeof(*hdr)),
 520                      PAGE_SIZE - sizeof(*hdr));
 521         start = (get_random_int() % hole) & ~(alignment - 1);
 522
 523         /* Leave a random number of instructions before BPF code. */
 524         *image_ptr = &hdr->image[start];
 525
 526         return hdr;
 527 }
 528
 529 void bpf_jit_binary_free(struct bpf_binary_header *hdr)
 530 {
 531         module_memfree(hdr);
 532 }
 533
 534 /* This symbol is only overridden by archs that have different
 535  * requirements than the usual eBPF JITs, f.e. when they only
 536  * implement cBPF JIT, do not set images read-only, etc.
 537  */
 538 void __weak bpf_jit_free(struct bpf_prog *fp)
 539 {
 540         if (fp->jited) {
 541                 struct bpf_binary_header *hdr = bpf_jit_binary_hdr(fp);
 542
 543                 bpf_jit_binary_unlock_ro(hdr);
 544                 bpf_jit_binary_free(hdr);
 545
 546                 WARN_ON_ONCE(!bpf_prog_kallsyms_verify_off(fp));
 547         }
 548
 549         bpf_prog_unlock_free(fp);
 550 }
 551
 552 int bpf_jit_harden __read_mostly;
 553
 554 static int bpf_jit_blind_insn(const struct bpf_insn *from,
 555                               const struct bpf_insn *aux,
 556                               struct bpf_insn *to_buff)
 557 {
 558         struct bpf_insn *to = to_buff;
 559         u32 imm_rnd = get_random_int();
 560         s16 off;
 561
 562         BUILD_BUG_ON(BPF_REG_AX  + 1 != MAX_BPF_JIT_REG);
 563         BUILD_BUG_ON(MAX_BPF_REG + 1 != MAX_BPF_JIT_REG);
 564
 565         if (from->imm == 0 &&
 566             (from->code == (BPF_ALU   | BPF_MOV | BPF_K) ||
 567              from->code == (BPF_ALU64 | BPF_MOV | BPF_K))) {
 568                 *to++ = BPF_ALU64_REG(BPF_XOR, from->dst_reg, from->dst_reg);
 569                 goto out;
 570         }
 571
 572         switch (from->code) {
 573         case BPF_ALU | BPF_ADD | BPF_K:
 574         case BPF_ALU | BPF_SUB | BPF_K:
 575         case BPF_ALU | BPF_AND | BPF_K:
 576         case BPF_ALU | BPF_OR  | BPF_K:
 577         case BPF_ALU | BPF_XOR | BPF_K:
 578         case BPF_ALU | BPF_MUL | BPF_K:
 579         case BPF_ALU | BPF_MOV | BPF_K:
 580         case BPF_ALU | BPF_DIV | BPF_K:
 581         case BPF_ALU | BPF_MOD | BPF_K:
 582                 *to++ = BPF_ALU32_IMM(BPF_MOV, BPF_REG_AX, imm_rnd ^ from->imm);
 583                 *to++ = BPF_ALU32_IMM(BPF_XOR, BPF_REG_AX, imm_rnd);
 584                 *to++ = BPF_ALU32_REG(from->code, from->dst_reg, BPF_REG_AX);
 585                 break;
 586
 587         case BPF_ALU64 | BPF_ADD | BPF_K:
 588         case BPF_ALU64 | BPF_SUB | BPF_K:
 589         case BPF_ALU64 | BPF_AND | BPF_K:
 590         case BPF_ALU64 | BPF_OR  | BPF_K:
 591         case BPF_ALU64 | BPF_XOR | BPF_K:
 592         case BPF_ALU64 | BPF_MUL | BPF_K:
 593         case BPF_ALU64 | BPF_MOV | BPF_K:
 594         case BPF_ALU64 | BPF_DIV | BPF_K:
 595         case BPF_ALU64 | BPF_MOD | BPF_K:
 596                 *to++ = BPF_ALU64_IMM(BPF_MOV, BPF_REG_AX, imm_rnd ^ from->imm);
 597                 *to++ = BPF_ALU64_IMM(BPF_XOR, BPF_REG_AX, imm_rnd);
 598                 *to++ = BPF_ALU64_REG(from->code, from->dst_reg, BPF_REG_AX);
 599                 break;
 600
 601         case BPF_JMP | BPF_JEQ  | BPF_K:
 602         case BPF_JMP | BPF_JNE  | BPF_K:
 603         case BPF_JMP | BPF_JGT  | BPF_K:
 604         case BPF_JMP | BPF_JGE  | BPF_K:
 605         case BPF_JMP | BPF_JSGT | BPF_K:
 606         case BPF_JMP | BPF_JSGE | BPF_K:
 607         case BPF_JMP | BPF_JSET | BPF_K:
 608                 /* Accommodate for extra offset in case of a backjump. */
 609                 off = from->off;
 610                 if (off < 0)
 611                         off -= 2;
 612                 *to++ = BPF_ALU64_IMM(BPF_MOV, BPF_REG_AX, imm_rnd ^ from->imm);
 613                 *to++ = BPF_ALU64_IMM(BPF_XOR, BPF_REG_AX, imm_rnd);
 614                 *to++ = BPF_JMP_REG(from->code, from->dst_reg, BPF_REG_AX, off);
 615                 break;
 616
 617         case BPF_LD | BPF_ABS | BPF_W:
 618         case BPF_LD | BPF_ABS | BPF_H:
 619         case BPF_LD | BPF_ABS | BPF_B:
 620                 *to++ = BPF_ALU64_IMM(BPF_MOV, BPF_REG_AX, imm_rnd ^ from->imm);
 621                 *to++ = BPF_ALU64_IMM(BPF_XOR, BPF_REG_AX, imm_rnd);
 622                 *to++ = BPF_LD_IND(from->code, BPF_REG_AX, 0);
 623                 break;
 624
 625         case BPF_LD | BPF_IND | BPF_W:
 626         case BPF_LD | BPF_IND | BPF_H:
 627         case BPF_LD | BPF_IND | BPF_B:
 628                 *to++ = BPF_ALU64_IMM(BPF_MOV, BPF_REG_AX, imm_rnd ^ from->imm);
 629                 *to++ = BPF_ALU64_IMM(BPF_XOR, BPF_REG_AX, imm_rnd);
 630                 *to++ = BPF_ALU32_REG(BPF_ADD, BPF_REG_AX, from->src_reg);
 631                 *to++ = BPF_LD_IND(from->code, BPF_REG_AX, 0);
 632                 break;
 633
 634         case BPF_LD | BPF_IMM | BPF_DW:
 635                 *to++ = BPF_ALU64_IMM(BPF_MOV, BPF_REG_AX, imm_rnd ^ aux[1].imm);
 636                 *to++ = BPF_ALU64_IMM(BPF_XOR, BPF_REG_AX, imm_rnd);
 637                 *to++ = BPF_ALU64_IMM(BPF_LSH, BPF_REG_AX, 32);
 638                 *to++ = BPF_ALU64_REG(BPF_MOV, aux[0].dst_reg, BPF_REG_AX);
 639                 break;
 640         case 0: /* Part 2 of BPF_LD | BPF_IMM | BPF_DW. */
 641                 *to++ = BPF_ALU32_IMM(BPF_MOV, BPF_REG_AX, imm_rnd ^ aux[0].imm);
 642                 *to++ = BPF_ALU32_IMM(BPF_XOR, BPF_REG_AX, imm_rnd);
 643                 *to++ = BPF_ALU64_REG(BPF_OR,  aux[0].dst_reg, BPF_REG_AX);
 644                 break;
 645
 646         case BPF_ST | BPF_MEM | BPF_DW:
 647         case BPF_ST | BPF_MEM | BPF_W:
 648         case BPF_ST | BPF_MEM | BPF_H:
 649         case BPF_ST | BPF_MEM | BPF_B:
 650                 *to++ = BPF_ALU64_IMM(BPF_MOV, BPF_REG_AX, imm_rnd ^ from->imm);
 651                 *to++ = BPF_ALU64_IMM(BPF_XOR, BPF_REG_AX, imm_rnd);
 652                 *to++ = BPF_STX_MEM(from->code, from->dst_reg, BPF_REG_AX, from->off);
 653                 break;
 654         }
 655 out:
 656         return to - to_buff;
 657 }
 658
 659 static struct bpf_prog *bpf_prog_clone_create(struct bpf_prog *fp_other,
 660                                               gfp_t gfp_extra_flags)
 661 {
 662         gfp_t gfp_flags = GFP_KERNEL | __GFP_HIGHMEM | __GFP_ZERO |
 663                           gfp_extra_flags;
 664         struct bpf_prog *fp;
 665
 666         fp = __vmalloc(fp_other->pages * PAGE_SIZE, gfp_flags, PAGE_KERNEL);
 667         if (fp != NULL) {
 668                 kmemcheck_annotate_bitfield(fp, meta);
 669
 670                 /* aux->prog still points to the fp_other one, so
 671                  * when promoting the clone to the real program,
 672                  * this still needs to be adapted.
 673                  */
 674                 memcpy(fp, fp_other, fp_other->pages * PAGE_SIZE);
 675         }
 676
 677         return fp;
 678 }
 679
 680 static void bpf_prog_clone_free(struct bpf_prog *fp)
 681 {
 682         /* aux was stolen by the other clone, so we cannot free
 683          * it from this path! It will be freed eventually by the
 684          * other program on release.
 685          *
 686          * At this point, we don't need a deferred release since
 687          * clone is guaranteed to not be locked.
 688          */
 689         fp->aux = NULL;
 690         __bpf_prog_free(fp);
 691 }
 692
 693 void bpf_jit_prog_release_other(struct bpf_prog *fp, struct bpf_prog *fp_other)
 694 {
 695         /* We have to repoint aux->prog to self, as we don't
 696          * know whether fp here is the clone or the original.
 697          */
 698         fp->aux->prog = fp;
 699         bpf_prog_clone_free(fp_other);
 700 }
 701
 702 struct bpf_prog *bpf_jit_blind_constants(struct bpf_prog *prog)
 703 {
 704         struct bpf_insn insn_buff[16], aux[2];
 705         struct bpf_prog *clone, *tmp;
 706         int insn_delta, insn_cnt;
 707         struct bpf_insn *insn;
 708         int i, rewritten;
 709
 710         if (!bpf_jit_blinding_enabled())
 711                 return prog;
 712
 713         clone = bpf_prog_clone_create(prog, GFP_USER);
 714         if (!clone)
 715                 return ERR_PTR(-ENOMEM);
 716
 717         insn_cnt = clone->len;
 718         insn = clone->insnsi;
 719
 720         for (i = 0; i < insn_cnt; i++, insn++) {
 721                 /* We temporarily need to hold the original ld64 insn
 722                  * so that we can still access the first part in the
 723                  * second blinding run.
 724                  */
 725                 if (insn[0].code == (BPF_LD | BPF_IMM | BPF_DW) &&
 726                     insn[1].code == 0)
 727                         memcpy(aux, insn, sizeof(aux));
 728
 729                 rewritten = bpf_jit_blind_insn(insn, aux, insn_buff);
 730                 if (!rewritten)
 731                         continue;
 732
 733                 tmp = bpf_patch_insn_single(clone, i, insn_buff, rewritten);
 734                 if (!tmp) {
 735                         /* Patching may have repointed aux->prog during
 736                          * realloc from the original one, so we need to
 737                          * fix it up here on error.
 738                          */
 739                         bpf_jit_prog_release_other(prog, clone);
 740                         return ERR_PTR(-ENOMEM);
 741                 }
 742
 743                 clone = tmp;
 744                 insn_delta = rewritten - 1;
 745
 746                 /* Walk new program and skip insns we just inserted. */
 747                 insn = clone->insnsi + i + insn_delta;
 748                 insn_cnt += insn_delta;
 749                 i        += insn_delta;
 750         }
 751
 752         return clone;
 753 }
 754 #endif /* CONFIG_BPF_JIT */
 755
 756 /* Base function for offset calculation. Needs to go into .text section,
 757  * therefore keeping it non-static as well; will also be used by JITs
 758  * anyway later on, so do not let the compiler omit it.
 759  */
 760 noinline u64 __bpf_call_base(u64 r1, u64 r2, u64 r3, u64 r4, u64 r5)
 761 {
 762         return 0;
 763 }
 764 EXPORT_SYMBOL_GPL(__bpf_call_base);
 765
 766 /**
 767  *      __bpf_prog_run - run eBPF program on a given context
 768  *      @ctx: is the data we are operating on
 769  *      @insn: is the array of eBPF instructions
 770  *
 771  * Decode and execute eBPF instructions.
 772  */
 773 static unsigned int __bpf_prog_run(void *ctx, const struct bpf_insn *insn)
 774 {
 775         u64 stack[MAX_BPF_STACK / sizeof(u64)];
 776         u64 regs[MAX_BPF_REG], tmp;
 777         static const void *jumptable[256] = {
 778                 [0 ... 255] = &&default_label,
 779                 /* Now overwrite non-defaults ... */
 780                 /* 32 bit ALU operations */
 781                 [BPF_ALU | BPF_ADD | BPF_X] = &&ALU_ADD_X,
 782                 [BPF_ALU | BPF_ADD | BPF_K] = &&ALU_ADD_K,
 783                 [BPF_ALU | BPF_SUB | BPF_X] = &&ALU_SUB_X,
 784                 [BPF_ALU | BPF_SUB | BPF_K] = &&ALU_SUB_K,
 785                 [BPF_ALU | BPF_AND | BPF_X] = &&ALU_AND_X,
 786                 [BPF_ALU | BPF_AND | BPF_K] = &&ALU_AND_K,
 787                 [BPF_ALU | BPF_OR | BPF_X]  = &&ALU_OR_X,
 788                 [BPF_ALU | BPF_OR | BPF_K]  = &&ALU_OR_K,
 789                 [BPF_ALU | BPF_LSH | BPF_X] = &&ALU_LSH_X,
 790                 [BPF_ALU | BPF_LSH | BPF_K] = &&ALU_LSH_K,
 791                 [BPF_ALU | BPF_RSH | BPF_X] = &&ALU_RSH_X,
 792                 [BPF_ALU | BPF_RSH | BPF_K] = &&ALU_RSH_K,
 793                 [BPF_ALU | BPF_XOR | BPF_X] = &&ALU_XOR_X,
 794                 [BPF_ALU | BPF_XOR | BPF_K] = &&ALU_XOR_K,
 795                 [BPF_ALU | BPF_MUL | BPF_X] = &&ALU_MUL_X,
 796                 [BPF_ALU | BPF_MUL | BPF_K] = &&ALU_MUL_K,
 797                 [BPF_ALU | BPF_MOV | BPF_X] = &&ALU_MOV_X,
 798                 [BPF_ALU | BPF_MOV | BPF_K] = &&ALU_MOV_K,
 799                 [BPF_ALU | BPF_DIV | BPF_X] = &&ALU_DIV_X,
 800                 [BPF_ALU | BPF_DIV | BPF_K] = &&ALU_DIV_K,
 801                 [BPF_ALU | BPF_MOD | BPF_X] = &&ALU_MOD_X,
 802                 [BPF_ALU | BPF_MOD | BPF_K] = &&ALU_MOD_K,
 803                 [BPF_ALU | BPF_NEG] = &&ALU_NEG,
 804                 [BPF_ALU | BPF_END | BPF_TO_BE] = &&ALU_END_TO_BE,
 805                 [BPF_ALU | BPF_END | BPF_TO_LE] = &&ALU_END_TO_LE,
 806                 /* 64 bit ALU operations */
 807                 [BPF_ALU64 | BPF_ADD | BPF_X] = &&ALU64_ADD_X,
 808                 [BPF_ALU64 | BPF_ADD | BPF_K] = &&ALU64_ADD_K,
 809                 [BPF_ALU64 | BPF_SUB | BPF_X] = &&ALU64_SUB_X,
 810                 [BPF_ALU64 | BPF_SUB | BPF_K] = &&ALU64_SUB_K,
 811                 [BPF_ALU64 | BPF_AND | BPF_X] = &&ALU64_AND_X,
 812                 [BPF_ALU64 | BPF_AND | BPF_K] = &&ALU64_AND_K,
 813                 [BPF_ALU64 | BPF_OR | BPF_X] = &&ALU64_OR_X,
 814                 [BPF_ALU64 | BPF_OR | BPF_K] = &&ALU64_OR_K,
 815                 [BPF_ALU64 | BPF_LSH | BPF_X] = &&ALU64_LSH_X,
 816                 [BPF_ALU64 | BPF_LSH | BPF_K] = &&ALU64_LSH_K,
 817                 [BPF_ALU64 | BPF_RSH | BPF_X] = &&ALU64_RSH_X,
 818                 [BPF_ALU64 | BPF_RSH | BPF_K] = &&ALU64_RSH_K,
 819                 [BPF_ALU64 | BPF_XOR | BPF_X] = &&ALU64_XOR_X,
 820                 [BPF_ALU64 | BPF_XOR | BPF_K] = &&ALU64_XOR_K,
 821                 [BPF_ALU64 | BPF_MUL | BPF_X] = &&ALU64_MUL_X,
 822                 [BPF_ALU64 | BPF_MUL | BPF_K] = &&ALU64_MUL_K,
 823                 [BPF_ALU64 | BPF_MOV | BPF_X] = &&ALU64_MOV_X,
 824                 [BPF_ALU64 | BPF_MOV | BPF_K] = &&ALU64_MOV_K,
 825                 [BPF_ALU64 | BPF_ARSH | BPF_X] = &&ALU64_ARSH_X,
 826                 [BPF_ALU64 | BPF_ARSH | BPF_K] = &&ALU64_ARSH_K,
 827                 [BPF_ALU64 | BPF_DIV | BPF_X] = &&ALU64_DIV_X,
 828                 [BPF_ALU64 | BPF_DIV | BPF_K] = &&ALU64_DIV_K,
 829                 [BPF_ALU64 | BPF_MOD | BPF_X] = &&ALU64_MOD_X,
 830                 [BPF_ALU64 | BPF_MOD | BPF_K] = &&ALU64_MOD_K,
 831                 [BPF_ALU64 | BPF_NEG] = &&ALU64_NEG,
 832                 /* Call instruction */
 833                 [BPF_JMP | BPF_CALL] = &&JMP_CALL,
 834                 [BPF_JMP | BPF_CALL | BPF_X] = &&JMP_TAIL_CALL,
 835                 /* Jumps */
 836                 [BPF_JMP | BPF_JA] = &&JMP_JA,
 837                 [BPF_JMP | BPF_JEQ | BPF_X] = &&JMP_JEQ_X,
 838                 [BPF_JMP | BPF_JEQ | BPF_K] = &&JMP_JEQ_K,
 839                 [BPF_JMP | BPF_JNE | BPF_X] = &&JMP_JNE_X,
 840                 [BPF_JMP | BPF_JNE | BPF_K] = &&JMP_JNE_K,
 841                 [BPF_JMP | BPF_JGT | BPF_X] = &&JMP_JGT_X,
 842                 [BPF_JMP | BPF_JGT | BPF_K] = &&JMP_JGT_K,
 843                 [BPF_JMP | BPF_JGE | BPF_X] = &&JMP_JGE_X,
 844                 [BPF_JMP | BPF_JGE | BPF_K] = &&JMP_JGE_K,
 845                 [BPF_JMP | BPF_JSGT | BPF_X] = &&JMP_JSGT_X,
 846                 [BPF_JMP | BPF_JSGT | BPF_K] = &&JMP_JSGT_K,
 847                 [BPF_JMP | BPF_JSGE | BPF_X] = &&JMP_JSGE_X,
 848                 [BPF_JMP | BPF_JSGE | BPF_K] = &&JMP_JSGE_K,
 849                 [BPF_JMP | BPF_JSET | BPF_X] = &&JMP_JSET_X,
 850                 [BPF_JMP | BPF_JSET | BPF_K] = &&JMP_JSET_K,
 851                 /* Program return */
 852                 [BPF_JMP | BPF_EXIT] = &&JMP_EXIT,
 853                 /* Store instructions */
 854                 [BPF_STX | BPF_MEM | BPF_B] = &&STX_MEM_B,
 855                 [BPF_STX | BPF_MEM | BPF_H] = &&STX_MEM_H,
 856                 [BPF_STX | BPF_MEM | BPF_W] = &&STX_MEM_W,
 857                 [BPF_STX | BPF_MEM | BPF_DW] = &&STX_MEM_DW,
 858                 [BPF_STX | BPF_XADD | BPF_W] = &&STX_XADD_W,
 859                 [BPF_STX | BPF_XADD | BPF_DW] = &&STX_XADD_DW,
 860                 [BPF_ST | BPF_MEM | BPF_B] = &&ST_MEM_B,
 861                 [BPF_ST | BPF_MEM | BPF_H] = &&ST_MEM_H,
 862                 [BPF_ST | BPF_MEM | BPF_W] = &&ST_MEM_W,
 863                 [BPF_ST | BPF_MEM | BPF_DW] = &&ST_MEM_DW,
 864                 /* Load instructions */
 865                 [BPF_LDX | BPF_MEM | BPF_B] = &&LDX_MEM_B,
 866                 [BPF_LDX | BPF_MEM | BPF_H] = &&LDX_MEM_H,
 867                 [BPF_LDX | BPF_MEM | BPF_W] = &&LDX_MEM_W,
 868                 [BPF_LDX | BPF_MEM | BPF_DW] = &&LDX_MEM_DW,
 869                 [BPF_LD | BPF_ABS | BPF_W] = &&LD_ABS_W,
 870                 [BPF_LD | BPF_ABS | BPF_H] = &&LD_ABS_H,
 871                 [BPF_LD | BPF_ABS | BPF_B] = &&LD_ABS_B,
 872                 [BPF_LD | BPF_IND | BPF_W] = &&LD_IND_W,
 873                 [BPF_LD | BPF_IND | BPF_H] = &&LD_IND_H,
 874                 [BPF_LD | BPF_IND | BPF_B] = &&LD_IND_B,
 875                 [BPF_LD | BPF_IMM | BPF_DW] = &&LD_IMM_DW,
 876         };
 877         u32 tail_call_cnt = 0;
 878         void *ptr;
 879         int off;
 880
 881 #define CONT     ({ insn++; goto select_insn; })
 882 #define CONT_JMP ({ insn++; goto select_insn; })
 883
 884         FP = (u64) (unsigned long) &stack[ARRAY_SIZE(stack)];
 885         ARG1 = (u64) (unsigned long) ctx;
 886
 887 select_insn:
 888         goto *jumptable[insn->code];
 889
 890         /* ALU */
 891 #define ALU(OPCODE, OP)                 \
 892         ALU64_##OPCODE##_X:             \
 893                 DST = DST OP SRC;       \
 894                 CONT;                   \
 895         ALU_##OPCODE##_X:               \
 896                 DST = (u32) DST OP (u32) SRC;   \
 897                 CONT;                   \
 898         ALU64_##OPCODE##_K:             \
 899                 DST = DST OP IMM;               \
 900                 CONT;                   \
 901         ALU_##OPCODE##_K:               \
 902                 DST = (u32) DST OP (u32) IMM;   \
 903                 CONT;
 904
 905         ALU(ADD,  +)
 906         ALU(SUB,  -)
 907         ALU(AND,  &)
 908         ALU(OR,   |)
 909         ALU(LSH, <<)
 910         ALU(RSH, >>)
 911         ALU(XOR,  ^)
 912         ALU(MUL,  *)
 913 #undef ALU
 914         ALU_NEG:
 915                 DST = (u32) -DST;
 916                 CONT;
 917         ALU64_NEG:
 918                 DST = -DST;
 919                 CONT;
 920         ALU_MOV_X:
 921                 DST = (u32) SRC;
 922                 CONT;
 923         ALU_MOV_K:
 924                 DST = (u32) IMM;
 925                 CONT;
 926         ALU64_MOV_X:
 927                 DST = SRC;
 928                 CONT;
 929         ALU64_MOV_K:
 930                 DST = IMM;
 931                 CONT;
 932         LD_IMM_DW:
 933                 DST = (u64) (u32) insn[0].imm | ((u64) (u32) insn[1].imm) << 32;
 934                 insn++;
 935                 CONT;
 936         ALU64_ARSH_X:
 937                 (*(s64 *) &DST) >>= SRC;
 938                 CONT;
 939         ALU64_ARSH_K:
 940                 (*(s64 *) &DST) >>= IMM;
 941                 CONT;
 942         ALU64_MOD_X:
 943                 if (unlikely(SRC == 0))
 944                         return 0;
 945                 div64_u64_rem(DST, SRC, &tmp);
 946                 DST = tmp;
 947                 CONT;
 948         ALU_MOD_X:
 949                 if (unlikely(SRC == 0))
 950                         return 0;
 951                 tmp = (u32) DST;
 952                 DST = do_div(tmp, (u32) SRC);
 953                 CONT;
 954         ALU64_MOD_K:
 955                 div64_u64_rem(DST, IMM, &tmp);
 956                 DST = tmp;
 957                 CONT;
 958         ALU_MOD_K:
 959                 tmp = (u32) DST;
 960                 DST = do_div(tmp, (u32) IMM);
 961                 CONT;
 962         ALU64_DIV_X:
 963                 if (unlikely(SRC == 0))
 964                         return 0;
 965                 DST = div64_u64(DST, SRC);
 966                 CONT;
 967         ALU_DIV_X:
 968                 if (unlikely(SRC == 0))
 969                         return 0;
 970                 tmp = (u32) DST;
 971                 do_div(tmp, (u32) SRC);
 972                 DST = (u32) tmp;
 973                 CONT;
 974         ALU64_DIV_K:
 975                 DST = div64_u64(DST, IMM);
 976                 CONT;
 977         ALU_DIV_K:
 978                 tmp = (u32) DST;
 979                 do_div(tmp, (u32) IMM);
 980                 DST = (u32) tmp;
 981                 CONT;
 982         ALU_END_TO_BE:
 983                 switch (IMM) {
 984                 case 16:
 985                         DST = (__force u16) cpu_to_be16(DST);
 986                         break;
 987                 case 32:
 988                         DST = (__force u32) cpu_to_be32(DST);
 989                         break;
 990                 case 64:
 991                         DST = (__force u64) cpu_to_be64(DST);
 992                         break;
 993                 }
 994                 CONT;
 995         ALU_END_TO_LE:
 996                 switch (IMM) {
 997                 case 16:
 998                         DST = (__force u16) cpu_to_le16(DST);
 999                         break;
1000                 case 32:
1001                         DST = (__force u32) cpu_to_le32(DST);
1002                         break;
1003                 case 64:
1004                         DST = (__force u64) cpu_to_le64(DST);
1005                         break;
1006                 }
1007                 CONT;
1008
1009         /* CALL */
1010         JMP_CALL:
1011                 /* Function call scratches BPF_R1-BPF_R5 registers,
1012                  * preserves BPF_R6-BPF_R9, and stores return value
1013                  * into BPF_R0.
1014                  */
1015                 BPF_R0 = (__bpf_call_base + insn->imm)(BPF_R1, BPF_R2, BPF_R3,
1016                                                        BPF_R4, BPF_R5);
1017                 CONT;
1018
1019         JMP_TAIL_CALL: {
1020                 struct bpf_map *map = (struct bpf_map *) (unsigned long) BPF_R2;
1021                 struct bpf_array *array = container_of(map, struct bpf_array, map);
1022                 struct bpf_prog *prog;
1023                 u64 index = BPF_R3;
1024
1025                 if (unlikely(index >= array->map.max_entries))
1026                         goto out;
1027                 if (unlikely(tail_call_cnt > MAX_TAIL_CALL_CNT))
1028                         goto out;
1029
1030                 tail_call_cnt++;
1031
1032                 prog = READ_ONCE(array->ptrs[index]);
1033                 if (!prog)
1034                         goto out;
1035
1036                 /* ARG1 at this point is guaranteed to point to CTX from
1037                  * the verifier side due to the fact that the tail call is
1038                  * handeled like a helper, that is, bpf_tail_call_proto,
1039                  * where arg1_type is ARG_PTR_TO_CTX.
1040                  */
1041                 insn = prog->insnsi;
1042                 goto select_insn;
1043 out:
1044                 CONT;
1045         }
1046         /* JMP */
1047         JMP_JA:
1048                 insn += insn->off;
1049                 CONT;
1050         JMP_JEQ_X:
1051                 if (DST == SRC) {
1052                         insn += insn->off;
1053                         CONT_JMP;
1054                 }
1055                 CONT;
1056         JMP_JEQ_K:
1057                 if (DST == IMM) {
1058                         insn += insn->off;
1059                         CONT_JMP;
1060                 }
1061                 CONT;
1062         JMP_JNE_X:
1063                 if (DST != SRC) {
1064                         insn += insn->off;
1065                         CONT_JMP;
1066                 }
1067                 CONT;
1068         JMP_JNE_K:
1069                 if (DST != IMM) {
1070                         insn += insn->off;
1071                         CONT_JMP;
1072                 }
1073                 CONT;
1074         JMP_JGT_X:
1075                 if (DST > SRC) {
1076                         insn += insn->off;
1077                         CONT_JMP;
1078                 }
1079                 CONT;
1080         JMP_JGT_K:
1081                 if (DST > IMM) {
1082                         insn += insn->off;
1083                         CONT_JMP;
1084                 }
1085                 CONT;
1086         JMP_JGE_X:
1087                 if (DST >= SRC) {
1088                         insn += insn->off;
1089                         CONT_JMP;
1090                 }
1091                 CONT;
1092         JMP_JGE_K:
1093                 if (DST >= IMM) {
1094                         insn += insn->off;
1095                         CONT_JMP;
1096                 }
1097                 CONT;
1098         JMP_JSGT_X:
1099                 if (((s64) DST) > ((s64) SRC)) {
1100                         insn += insn->off;
1101                         CONT_JMP;
1102                 }
1103                 CONT;
1104         JMP_JSGT_K:
1105                 if (((s64) DST) > ((s64) IMM)) {
1106                         insn += insn->off;
1107                         CONT_JMP;
1108                 }
1109                 CONT;
1110         JMP_JSGE_X:
1111                 if (((s64) DST) >= ((s64) SRC)) {
1112                         insn += insn->off;
1113                         CONT_JMP;
1114                 }
1115                 CONT;
1116         JMP_JSGE_K:
1117                 if (((s64) DST) >= ((s64) IMM)) {
1118                         insn += insn->off;
1119                         CONT_JMP;
1120                 }
1121                 CONT;
1122         JMP_JSET_X:
1123                 if (DST & SRC) {
1124                         insn += insn->off;
1125                         CONT_JMP;
1126                 }
1127                 CONT;
1128         JMP_JSET_K:
1129                 if (DST & IMM) {
1130                         insn += insn->off;
1131                         CONT_JMP;
1132                 }
1133                 CONT;
1134         JMP_EXIT:
1135                 return BPF_R0;
1136
1137         /* STX and ST and LDX*/
1138 #define LDST(SIZEOP, SIZE)                                              \
1139         STX_MEM_##SIZEOP:                                               \
1140                 *(SIZE *)(unsigned long) (DST + insn->off) = SRC;       \
1141                 CONT;                                                   \
1142         ST_MEM_##SIZEOP:                                                \
1143                 *(SIZE *)(unsigned long) (DST + insn->off) = IMM;       \
1144                 CONT;                                                   \
1145         LDX_MEM_##SIZEOP:                                               \
1146                 DST = *(SIZE *)(unsigned long) (SRC + insn->off);       \
1147                 CONT;
1148
1149         LDST(B,   u8)
1150         LDST(H,  u16)
1151         LDST(W,  u32)
1152         LDST(DW, u64)
1153 #undef LDST
1154         STX_XADD_W: /* lock xadd *(u32 *)(dst_reg + off16) += src_reg */
1155                 atomic_add((u32) SRC, (atomic_t *)(unsigned long)
1156                            (DST + insn->off));
1157                 CONT;
1158         STX_XADD_DW: /* lock xadd *(u64 *)(dst_reg + off16) += src_reg */
1159                 atomic64_add((u64) SRC, (atomic64_t *)(unsigned long)
1160                              (DST + insn->off));
1161                 CONT;
1162         LD_ABS_W: /* BPF_R0 = ntohl(*(u32 *) (skb->data + imm32)) */
1163                 off = IMM;
1164 load_word:
1165                 /* BPF_LD + BPD_ABS and BPF_LD + BPF_IND insns are only
1166                  * appearing in the programs where ctx == skb
1167                  * (see may_access_skb() in the verifier). All programs
1168                  * keep 'ctx' in regs[BPF_REG_CTX] == BPF_R6,
1169                  * bpf_convert_filter() saves it in BPF_R6, internal BPF
1170                  * verifier will check that BPF_R6 == ctx.
1171                  *
1172                  * BPF_ABS and BPF_IND are wrappers of function calls,
1173                  * so they scratch BPF_R1-BPF_R5 registers, preserve
1174                  * BPF_R6-BPF_R9, and store return value into BPF_R0.
1175                  *
1176                  * Implicit input:
1177                  *   ctx == skb == BPF_R6 == CTX
1178                  *
1179                  * Explicit input:
1180                  *   SRC == any register
1181                  *   IMM == 32-bit immediate
1182                  *
1183                  * Output:
1184                  *   BPF_R0 - 8/16/32-bit skb data converted to cpu endianness
1185                  */
1186
1187                 ptr = bpf_load_pointer((struct sk_buff *) (unsigned long) CTX, off, 4, &tmp);
1188                 if (likely(ptr != NULL)) {
1189                         BPF_R0 = get_unaligned_be32(ptr);
1190                         CONT;
1191                 }
1192
1193                 return 0;
1194         LD_ABS_H: /* BPF_R0 = ntohs(*(u16 *) (skb->data + imm32)) */
1195                 off = IMM;
1196 load_half:
1197                 ptr = bpf_load_pointer((struct sk_buff *) (unsigned long) CTX, off, 2, &tmp);
1198                 if (likely(ptr != NULL)) {
1199                         BPF_R0 = get_unaligned_be16(ptr);
1200                         CONT;
1201                 }
1202
1203                 return 0;
1204         LD_ABS_B: /* BPF_R0 = *(u8 *) (skb->data + imm32) */
1205                 off = IMM;
1206 load_byte:
1207                 ptr = bpf_load_pointer((struct sk_buff *) (unsigned long) CTX, off, 1, &tmp);
1208                 if (likely(ptr != NULL)) {
1209                         BPF_R0 = *(u8 *)ptr;
1210                         CONT;
1211                 }
1212
1213                 return 0;
1214         LD_IND_W: /* BPF_R0 = ntohl(*(u32 *) (skb->data + src_reg + imm32)) */
1215                 off = IMM + SRC;
1216                 goto load_word;
1217         LD_IND_H: /* BPF_R0 = ntohs(*(u16 *) (skb->data + src_reg + imm32)) */
1218                 off = IMM + SRC;
1219                 goto load_half;
1220         LD_IND_B: /* BPF_R0 = *(u8 *) (skb->data + src_reg + imm32) */
1221                 off = IMM + SRC;
1222                 goto load_byte;
1223
1224         default_label:
1225                 /* If we ever reach this, we have a bug somewhere. */
1226                 WARN_RATELIMIT(1, "unknown opcode %02x\n", insn->code);
1227                 return 0;
1228 }
1229 STACK_FRAME_NON_STANDARD(__bpf_prog_run); /* jump table */
1230
1231 bool bpf_prog_array_compatible(struct bpf_array *array,
1232                                const struct bpf_prog *fp)
1233 {
1234         if (!array->owner_prog_type) {
1235                 /* There's no owner yet where we could check for
1236                  * compatibility.
1237                  */
1238                 array->owner_prog_type = fp->type;
1239                 array->owner_jited = fp->jited;
1240
1241                 return true;
1242         }
1243
1244         return array->owner_prog_type == fp->type &&
1245                array->owner_jited == fp->jited;
1246 }
1247
1248 static int bpf_check_tail_call(const struct bpf_prog *fp)
1249 {
1250         struct bpf_prog_aux *aux = fp->aux;
1251         int i;
1252
1253         for (i = 0; i < aux->used_map_cnt; i++) {
1254                 struct bpf_map *map = aux->used_maps[i];
1255                 struct bpf_array *array;
1256
1257                 if (map->map_type != BPF_MAP_TYPE_PROG_ARRAY)
1258                         continue;
1259
1260                 array = container_of(map, struct bpf_array, map);
1261                 if (!bpf_prog_array_compatible(array, fp))
1262                         return -EINVAL;
1263         }
1264
1265         return 0;
1266 }
1267
1268 /**
1269  *      bpf_prog_select_runtime - select exec runtime for BPF program
1270  *      @fp: bpf_prog populated with internal BPF program
1271  *      @err: pointer to error variable
1272  *
1273  * Try to JIT eBPF program, if JIT is not available, use interpreter.
1274  * The BPF program will be executed via BPF_PROG_RUN() macro.
1275  */
1276 struct bpf_prog *bpf_prog_select_runtime(struct bpf_prog *fp, int *err)
1277 {
1278         fp->bpf_func = (void *) __bpf_prog_run;
1279
1280         /* eBPF JITs can rewrite the program in case constant
1281          * blinding is active. However, in case of error during
1282          * blinding, bpf_int_jit_compile() must always return a
1283          * valid program, which in this case would simply not
1284          * be JITed, but falls back to the interpreter.
1285          */
1286         fp = bpf_int_jit_compile(fp);
1287         bpf_prog_lock_ro(fp);
1288
1289         /* The tail call compatibility check can only be done at
1290          * this late stage as we need to determine, if we deal
1291          * with JITed or non JITed program concatenations and not
1292          * all eBPF JITs might immediately support all features.
1293          */
1294         *err = bpf_check_tail_call(fp);
1295
1296         return fp;
1297 }
1298 EXPORT_SYMBOL_GPL(bpf_prog_select_runtime);
1299
1300 static void bpf_prog_free_deferred(struct work_struct *work)
1301 {
1302         struct bpf_prog_aux *aux;
1303
1304         aux = container_of(work, struct bpf_prog_aux, work);
1305         bpf_jit_free(aux->prog);
1306 }
1307
1308 /* Free internal BPF program */
1309 void bpf_prog_free(struct bpf_prog *fp)
1310 {
1311         struct bpf_prog_aux *aux = fp->aux;
1312
1313         INIT_WORK(&aux->work, bpf_prog_free_deferred);
1314         schedule_work(&aux->work);
1315 }
1316 EXPORT_SYMBOL_GPL(bpf_prog_free);
1317
1318 /* RNG for unpriviledged user space with separated state from prandom_u32(). */
1319 static DEFINE_PER_CPU(struct rnd_state, bpf_user_rnd_state);
1320
1321 void bpf_user_rnd_init_once(void)
1322 {
1323         prandom_init_once(&bpf_user_rnd_state);
1324 }
1325
1326 BPF_CALL_0(bpf_user_rnd_u32)
1327 {
1328         /* Should someone ever have the rather unwise idea to use some
1329          * of the registers passed into this function, then note that
1330          * this function is called from native eBPF and classic-to-eBPF
1331          * transformations. Register assignments from both sides are
1332          * different, f.e. classic always sets fn(ctx, A, X) here.
1333          */
1334         struct rnd_state *state;
1335         u32 res;
1336
1337         state = &get_cpu_var(bpf_user_rnd_state);
1338         res = prandom_u32_state(state);
1339         put_cpu_var(bpf_user_rnd_state);
1340
1341         return res;
1342 }
1343
1344 /* Weak definitions of helper functions in case we don't have bpf syscall. */
1345 const struct bpf_func_proto bpf_map_lookup_elem_proto __weak;
1346 const struct bpf_func_proto bpf_map_update_elem_proto __weak;
1347 const struct bpf_func_proto bpf_map_delete_elem_proto __weak;
1348
1349 const struct bpf_func_proto bpf_get_prandom_u32_proto __weak;
1350 const struct bpf_func_proto bpf_get_smp_processor_id_proto __weak;
1351 const struct bpf_func_proto bpf_get_numa_node_id_proto __weak;
1352 const struct bpf_func_proto bpf_ktime_get_ns_proto __weak;
1353
1354 const struct bpf_func_proto bpf_get_current_pid_tgid_proto __weak;
1355 const struct bpf_func_proto bpf_get_current_uid_gid_proto __weak;
1356 const struct bpf_func_proto bpf_get_current_comm_proto __weak;
1357
1358 const struct bpf_func_proto * __weak bpf_get_trace_printk_proto(void)
1359 {
1360         return NULL;
1361 }
1362
1363 u64 __weak
1364 bpf_event_output(struct bpf_map *map, u64 flags, void *meta, u64 meta_size,
1365                  void *ctx, u64 ctx_size, bpf_ctx_copy_t ctx_copy)
1366 {
1367         return -ENOTSUPP;
1368 }
1369
1370 /* Always built-in helper functions. */
1371 const struct bpf_func_proto bpf_tail_call_proto = {
1372         .func           = NULL,
1373         .gpl_only       = false,
1374         .ret_type       = RET_VOID,
1375         .arg1_type      = ARG_PTR_TO_CTX,
1376         .arg2_type      = ARG_CONST_MAP_PTR,
1377         .arg3_type      = ARG_ANYTHING,
1378 };
1379
1380 /* Stub for JITs that only support cBPF. eBPF programs are interpreted.
1381  * It is encouraged to implement bpf_int_jit_compile() instead, so that
1382  * eBPF and implicitly also cBPF can get JITed!
1383  */
1384 struct bpf_prog * __weak bpf_int_jit_compile(struct bpf_prog *prog)
1385 {
1386         return prog;
1387 }
1388
1389 /* Stub for JITs that support eBPF. All cBPF code gets transformed into
1390  * eBPF by the kernel and is later compiled by bpf_int_jit_compile().
1391  */
1392 void __weak bpf_jit_compile(struct bpf_prog *prog)
1393 {
1394 }
1395
1396 bool __weak bpf_helper_changes_pkt_data(void *func)
1397 {
1398         return false;
1399 }
1400
1401 /* To execute LD_ABS/LD_IND instructions __bpf_prog_run() may call
1402  * skb_copy_bits(), so provide a weak definition of it for NET-less config.
1403  */
1404 int __weak skb_copy_bits(const struct sk_buff *skb, int offset, void *to,
1405                          int len)
1406 {
1407         return -EFAULT;
1408 }
1409
1410 /* All definitions of tracepoints related to BPF. */
1411 #define CREATE_TRACE_POINTS
1412 #include <linux/bpf_trace.h>
1413
1414 EXPORT_TRACEPOINT_SYMBOL_GPL(xdp_exception);
1415
1416 EXPORT_TRACEPOINT_SYMBOL_GPL(bpf_prog_get_type);
1417 EXPORT_TRACEPOINT_SYMBOL_GPL(bpf_prog_put_rcu);