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 <asm/unaligned.h>
  30 #include <linux/bpf.h>
  31
  32 /* Registers */
  33 #define BPF_R0  regs[BPF_REG_0]
  34 #define BPF_R1  regs[BPF_REG_1]
  35 #define BPF_R2  regs[BPF_REG_2]
  36 #define BPF_R3  regs[BPF_REG_3]
  37 #define BPF_R4  regs[BPF_REG_4]
  38 #define BPF_R5  regs[BPF_REG_5]
  39 #define BPF_R6  regs[BPF_REG_6]
  40 #define BPF_R7  regs[BPF_REG_7]
  41 #define BPF_R8  regs[BPF_REG_8]
  42 #define BPF_R9  regs[BPF_REG_9]
  43 #define BPF_R10 regs[BPF_REG_10]
  44
  45 /* Named registers */
  46 #define DST     regs[insn->dst_reg]
  47 #define SRC     regs[insn->src_reg]
  48 #define FP      regs[BPF_REG_FP]
  49 #define ARG1    regs[BPF_REG_ARG1]
  50 #define CTX     regs[BPF_REG_CTX]
  51 #define IMM     insn->imm
  52
  53 /* No hurry in this branch
  54  *
  55  * Exported for the bpf jit load helper.
  56  */
  57 void *bpf_internal_load_pointer_neg_helper(const struct sk_buff *skb, int k, unsigned int size)
  58 {
  59         u8 *ptr = NULL;
  60
  61         if (k >= SKF_NET_OFF)
  62                 ptr = skb_network_header(skb) + k - SKF_NET_OFF;
  63         else if (k >= SKF_LL_OFF)
  64                 ptr = skb_mac_header(skb) + k - SKF_LL_OFF;
  65         if (ptr >= skb->head && ptr + size <= skb_tail_pointer(skb))
  66                 return ptr;
  67
  68         return NULL;
  69 }
  70
  71 struct bpf_prog *bpf_prog_alloc(unsigned int size, gfp_t gfp_extra_flags)
  72 {
  73         gfp_t gfp_flags = GFP_KERNEL | __GFP_HIGHMEM | __GFP_ZERO |
  74                           gfp_extra_flags;
  75         struct bpf_prog_aux *aux;
  76         struct bpf_prog *fp;
  77
  78         size = round_up(size, PAGE_SIZE);
  79         fp = __vmalloc(size, gfp_flags, PAGE_KERNEL);
  80         if (fp == NULL)
  81                 return NULL;
  82
  83         aux = kzalloc(sizeof(*aux), GFP_KERNEL | gfp_extra_flags);
  84         if (aux == NULL) {
  85                 vfree(fp);
  86                 return NULL;
  87         }
  88
  89         fp->pages = size / PAGE_SIZE;
  90         fp->aux = aux;
  91
  92         return fp;
  93 }
  94 EXPORT_SYMBOL_GPL(bpf_prog_alloc);
  95
  96 struct bpf_prog *bpf_prog_realloc(struct bpf_prog *fp_old, unsigned int size,
  97                                   gfp_t gfp_extra_flags)
  98 {
  99         gfp_t gfp_flags = GFP_KERNEL | __GFP_HIGHMEM | __GFP_ZERO |
 100                           gfp_extra_flags;
 101         struct bpf_prog *fp;
 102
 103         BUG_ON(fp_old == NULL);
 104
 105         size = round_up(size, PAGE_SIZE);
 106         if (size <= fp_old->pages * PAGE_SIZE)
 107                 return fp_old;
 108
 109         fp = __vmalloc(size, gfp_flags, PAGE_KERNEL);
 110         if (fp != NULL) {
 111                 memcpy(fp, fp_old, fp_old->pages * PAGE_SIZE);
 112                 fp->pages = size / PAGE_SIZE;
 113
 114                 /* We keep fp->aux from fp_old around in the new
 115                  * reallocated structure.
 116                  */
 117                 fp_old->aux = NULL;
 118                 __bpf_prog_free(fp_old);
 119         }
 120
 121         return fp;
 122 }
 123 EXPORT_SYMBOL_GPL(bpf_prog_realloc);
 124
 125 void __bpf_prog_free(struct bpf_prog *fp)
 126 {
 127         kfree(fp->aux);
 128         vfree(fp);
 129 }
 130 EXPORT_SYMBOL_GPL(__bpf_prog_free);
 131
 132 #ifdef CONFIG_BPF_JIT
 133 struct bpf_binary_header *
 134 bpf_jit_binary_alloc(unsigned int proglen, u8 **image_ptr,
 135                      unsigned int alignment,
 136                      bpf_jit_fill_hole_t bpf_fill_ill_insns)
 137 {
 138         struct bpf_binary_header *hdr;
 139         unsigned int size, hole, start;
 140
 141         /* Most of BPF filters are really small, but if some of them
 142          * fill a page, allow at least 128 extra bytes to insert a
 143          * random section of illegal instructions.
 144          */
 145         size = round_up(proglen + sizeof(*hdr) + 128, PAGE_SIZE);
 146         hdr = module_alloc(size);
 147         if (hdr == NULL)
 148                 return NULL;
 149
 150         /* Fill space with illegal/arch-dep instructions. */
 151         bpf_fill_ill_insns(hdr, size);
 152
 153         hdr->pages = size / PAGE_SIZE;
 154         hole = min_t(unsigned int, size - (proglen + sizeof(*hdr)),
 155                      PAGE_SIZE - sizeof(*hdr));
 156         start = (prandom_u32() % hole) & ~(alignment - 1);
 157
 158         /* Leave a random number of instructions before BPF code. */
 159         *image_ptr = &hdr->image[start];
 160
 161         return hdr;
 162 }
 163
 164 void bpf_jit_binary_free(struct bpf_binary_header *hdr)
 165 {
 166         module_memfree(hdr);
 167 }
 168 #endif /* CONFIG_BPF_JIT */
 169
 170 /* Base function for offset calculation. Needs to go into .text section,
 171  * therefore keeping it non-static as well; will also be used by JITs
 172  * anyway later on, so do not let the compiler omit it.
 173  */
 174 noinline u64 __bpf_call_base(u64 r1, u64 r2, u64 r3, u64 r4, u64 r5)
 175 {
 176         return 0;
 177 }
 178
 179 /**
 180  *      __bpf_prog_run - run eBPF program on a given context
 181  *      @ctx: is the data we are operating on
 182  *      @insn: is the array of eBPF instructions
 183  *
 184  * Decode and execute eBPF instructions.
 185  */
 186 static unsigned int __bpf_prog_run(void *ctx, const struct bpf_insn *insn)
 187 {
 188         u64 stack[MAX_BPF_STACK / sizeof(u64)];
 189         u64 regs[MAX_BPF_REG], tmp;
 190         static const void *jumptable[256] = {
 191                 [0 ... 255] = &&default_label,
 192                 /* Now overwrite non-defaults ... */
 193                 /* 32 bit ALU operations */
 194                 [BPF_ALU | BPF_ADD | BPF_X] = &&ALU_ADD_X,
 195                 [BPF_ALU | BPF_ADD | BPF_K] = &&ALU_ADD_K,
 196                 [BPF_ALU | BPF_SUB | BPF_X] = &&ALU_SUB_X,
 197                 [BPF_ALU | BPF_SUB | BPF_K] = &&ALU_SUB_K,
 198                 [BPF_ALU | BPF_AND | BPF_X] = &&ALU_AND_X,
 199                 [BPF_ALU | BPF_AND | BPF_K] = &&ALU_AND_K,
 200                 [BPF_ALU | BPF_OR | BPF_X]  = &&ALU_OR_X,
 201                 [BPF_ALU | BPF_OR | BPF_K]  = &&ALU_OR_K,
 202                 [BPF_ALU | BPF_LSH | BPF_X] = &&ALU_LSH_X,
 203                 [BPF_ALU | BPF_LSH | BPF_K] = &&ALU_LSH_K,
 204                 [BPF_ALU | BPF_RSH | BPF_X] = &&ALU_RSH_X,
 205                 [BPF_ALU | BPF_RSH | BPF_K] = &&ALU_RSH_K,
 206                 [BPF_ALU | BPF_XOR | BPF_X] = &&ALU_XOR_X,
 207                 [BPF_ALU | BPF_XOR | BPF_K] = &&ALU_XOR_K,
 208                 [BPF_ALU | BPF_MUL | BPF_X] = &&ALU_MUL_X,
 209                 [BPF_ALU | BPF_MUL | BPF_K] = &&ALU_MUL_K,
 210                 [BPF_ALU | BPF_MOV | BPF_X] = &&ALU_MOV_X,
 211                 [BPF_ALU | BPF_MOV | BPF_K] = &&ALU_MOV_K,
 212                 [BPF_ALU | BPF_DIV | BPF_X] = &&ALU_DIV_X,
 213                 [BPF_ALU | BPF_DIV | BPF_K] = &&ALU_DIV_K,
 214                 [BPF_ALU | BPF_MOD | BPF_X] = &&ALU_MOD_X,
 215                 [BPF_ALU | BPF_MOD | BPF_K] = &&ALU_MOD_K,
 216                 [BPF_ALU | BPF_NEG] = &&ALU_NEG,
 217                 [BPF_ALU | BPF_END | BPF_TO_BE] = &&ALU_END_TO_BE,
 218                 [BPF_ALU | BPF_END | BPF_TO_LE] = &&ALU_END_TO_LE,
 219                 /* 64 bit ALU operations */
 220                 [BPF_ALU64 | BPF_ADD | BPF_X] = &&ALU64_ADD_X,
 221                 [BPF_ALU64 | BPF_ADD | BPF_K] = &&ALU64_ADD_K,
 222                 [BPF_ALU64 | BPF_SUB | BPF_X] = &&ALU64_SUB_X,
 223                 [BPF_ALU64 | BPF_SUB | BPF_K] = &&ALU64_SUB_K,
 224                 [BPF_ALU64 | BPF_AND | BPF_X] = &&ALU64_AND_X,
 225                 [BPF_ALU64 | BPF_AND | BPF_K] = &&ALU64_AND_K,
 226                 [BPF_ALU64 | BPF_OR | BPF_X] = &&ALU64_OR_X,
 227                 [BPF_ALU64 | BPF_OR | BPF_K] = &&ALU64_OR_K,
 228                 [BPF_ALU64 | BPF_LSH | BPF_X] = &&ALU64_LSH_X,
 229                 [BPF_ALU64 | BPF_LSH | BPF_K] = &&ALU64_LSH_K,
 230                 [BPF_ALU64 | BPF_RSH | BPF_X] = &&ALU64_RSH_X,
 231                 [BPF_ALU64 | BPF_RSH | BPF_K] = &&ALU64_RSH_K,
 232                 [BPF_ALU64 | BPF_XOR | BPF_X] = &&ALU64_XOR_X,
 233                 [BPF_ALU64 | BPF_XOR | BPF_K] = &&ALU64_XOR_K,
 234                 [BPF_ALU64 | BPF_MUL | BPF_X] = &&ALU64_MUL_X,
 235                 [BPF_ALU64 | BPF_MUL | BPF_K] = &&ALU64_MUL_K,
 236                 [BPF_ALU64 | BPF_MOV | BPF_X] = &&ALU64_MOV_X,
 237                 [BPF_ALU64 | BPF_MOV | BPF_K] = &&ALU64_MOV_K,
 238                 [BPF_ALU64 | BPF_ARSH | BPF_X] = &&ALU64_ARSH_X,
 239                 [BPF_ALU64 | BPF_ARSH | BPF_K] = &&ALU64_ARSH_K,
 240                 [BPF_ALU64 | BPF_DIV | BPF_X] = &&ALU64_DIV_X,
 241                 [BPF_ALU64 | BPF_DIV | BPF_K] = &&ALU64_DIV_K,
 242                 [BPF_ALU64 | BPF_MOD | BPF_X] = &&ALU64_MOD_X,
 243                 [BPF_ALU64 | BPF_MOD | BPF_K] = &&ALU64_MOD_K,
 244                 [BPF_ALU64 | BPF_NEG] = &&ALU64_NEG,
 245                 /* Call instruction */
 246                 [BPF_JMP | BPF_CALL] = &&JMP_CALL,
 247                 /* Jumps */
 248                 [BPF_JMP | BPF_JA] = &&JMP_JA,
 249                 [BPF_JMP | BPF_JEQ | BPF_X] = &&JMP_JEQ_X,
 250                 [BPF_JMP | BPF_JEQ | BPF_K] = &&JMP_JEQ_K,
 251                 [BPF_JMP | BPF_JNE | BPF_X] = &&JMP_JNE_X,
 252                 [BPF_JMP | BPF_JNE | BPF_K] = &&JMP_JNE_K,
 253                 [BPF_JMP | BPF_JGT | BPF_X] = &&JMP_JGT_X,
 254                 [BPF_JMP | BPF_JGT | BPF_K] = &&JMP_JGT_K,
 255                 [BPF_JMP | BPF_JGE | BPF_X] = &&JMP_JGE_X,
 256                 [BPF_JMP | BPF_JGE | BPF_K] = &&JMP_JGE_K,
 257                 [BPF_JMP | BPF_JSGT | BPF_X] = &&JMP_JSGT_X,
 258                 [BPF_JMP | BPF_JSGT | BPF_K] = &&JMP_JSGT_K,
 259                 [BPF_JMP | BPF_JSGE | BPF_X] = &&JMP_JSGE_X,
 260                 [BPF_JMP | BPF_JSGE | BPF_K] = &&JMP_JSGE_K,
 261                 [BPF_JMP | BPF_JSET | BPF_X] = &&JMP_JSET_X,
 262                 [BPF_JMP | BPF_JSET | BPF_K] = &&JMP_JSET_K,
 263                 /* Program return */
 264                 [BPF_JMP | BPF_EXIT] = &&JMP_EXIT,
 265                 /* Store instructions */
 266                 [BPF_STX | BPF_MEM | BPF_B] = &&STX_MEM_B,
 267                 [BPF_STX | BPF_MEM | BPF_H] = &&STX_MEM_H,
 268                 [BPF_STX | BPF_MEM | BPF_W] = &&STX_MEM_W,
 269                 [BPF_STX | BPF_MEM | BPF_DW] = &&STX_MEM_DW,
 270                 [BPF_STX | BPF_XADD | BPF_W] = &&STX_XADD_W,
 271                 [BPF_STX | BPF_XADD | BPF_DW] = &&STX_XADD_DW,
 272                 [BPF_ST | BPF_MEM | BPF_B] = &&ST_MEM_B,
 273                 [BPF_ST | BPF_MEM | BPF_H] = &&ST_MEM_H,
 274                 [BPF_ST | BPF_MEM | BPF_W] = &&ST_MEM_W,
 275                 [BPF_ST | BPF_MEM | BPF_DW] = &&ST_MEM_DW,
 276                 /* Load instructions */
 277                 [BPF_LDX | BPF_MEM | BPF_B] = &&LDX_MEM_B,
 278                 [BPF_LDX | BPF_MEM | BPF_H] = &&LDX_MEM_H,
 279                 [BPF_LDX | BPF_MEM | BPF_W] = &&LDX_MEM_W,
 280                 [BPF_LDX | BPF_MEM | BPF_DW] = &&LDX_MEM_DW,
 281                 [BPF_LD | BPF_ABS | BPF_W] = &&LD_ABS_W,
 282                 [BPF_LD | BPF_ABS | BPF_H] = &&LD_ABS_H,
 283                 [BPF_LD | BPF_ABS | BPF_B] = &&LD_ABS_B,
 284                 [BPF_LD | BPF_IND | BPF_W] = &&LD_IND_W,
 285                 [BPF_LD | BPF_IND | BPF_H] = &&LD_IND_H,
 286                 [BPF_LD | BPF_IND | BPF_B] = &&LD_IND_B,
 287                 [BPF_LD | BPF_IMM | BPF_DW] = &&LD_IMM_DW,
 288         };
 289         void *ptr;
 290         int off;
 291
 292 #define CONT     ({ insn++; goto select_insn; })
 293 #define CONT_JMP ({ insn++; goto select_insn; })
 294
 295         FP = (u64) (unsigned long) &stack[ARRAY_SIZE(stack)];
 296         ARG1 = (u64) (unsigned long) ctx;
 297
 298         /* Registers used in classic BPF programs need to be reset first. */
 299         regs[BPF_REG_A] = 0;
 300         regs[BPF_REG_X] = 0;
 301
 302 select_insn:
 303         goto *jumptable[insn->code];
 304
 305         /* ALU */
 306 #define ALU(OPCODE, OP)                 \
 307         ALU64_##OPCODE##_X:             \
 308                 DST = DST OP SRC;       \
 309                 CONT;                   \
 310         ALU_##OPCODE##_X:               \
 311                 DST = (u32) DST OP (u32) SRC;   \
 312                 CONT;                   \
 313         ALU64_##OPCODE##_K:             \
 314                 DST = DST OP IMM;               \
 315                 CONT;                   \
 316         ALU_##OPCODE##_K:               \
 317                 DST = (u32) DST OP (u32) IMM;   \
 318                 CONT;
 319
 320         ALU(ADD,  +)
 321         ALU(SUB,  -)
 322         ALU(AND,  &)
 323         ALU(OR,   |)
 324         ALU(LSH, <<)
 325         ALU(RSH, >>)
 326         ALU(XOR,  ^)
 327         ALU(MUL,  *)
 328 #undef ALU
 329         ALU_NEG:
 330                 DST = (u32) -DST;
 331                 CONT;
 332         ALU64_NEG:
 333                 DST = -DST;
 334                 CONT;
 335         ALU_MOV_X:
 336                 DST = (u32) SRC;
 337                 CONT;
 338         ALU_MOV_K:
 339                 DST = (u32) IMM;
 340                 CONT;
 341         ALU64_MOV_X:
 342                 DST = SRC;
 343                 CONT;
 344         ALU64_MOV_K:
 345                 DST = IMM;
 346                 CONT;
 347         LD_IMM_DW:
 348                 DST = (u64) (u32) insn[0].imm | ((u64) (u32) insn[1].imm) << 32;
 349                 insn++;
 350                 CONT;
 351         ALU64_ARSH_X:
 352                 (*(s64 *) &DST) >>= SRC;
 353                 CONT;
 354         ALU64_ARSH_K:
 355                 (*(s64 *) &DST) >>= IMM;
 356                 CONT;
 357         ALU64_MOD_X:
 358                 if (unlikely(SRC == 0))
 359                         return 0;
 360                 tmp = DST;
 361                 DST = do_div(tmp, SRC);
 362                 CONT;
 363         ALU_MOD_X:
 364                 if (unlikely(SRC == 0))
 365                         return 0;
 366                 tmp = (u32) DST;
 367                 DST = do_div(tmp, (u32) SRC);
 368                 CONT;
 369         ALU64_MOD_K:
 370                 tmp = DST;
 371                 DST = do_div(tmp, IMM);
 372                 CONT;
 373         ALU_MOD_K:
 374                 tmp = (u32) DST;
 375                 DST = do_div(tmp, (u32) IMM);
 376                 CONT;
 377         ALU64_DIV_X:
 378                 if (unlikely(SRC == 0))
 379                         return 0;
 380                 do_div(DST, SRC);
 381                 CONT;
 382         ALU_DIV_X:
 383                 if (unlikely(SRC == 0))
 384                         return 0;
 385                 tmp = (u32) DST;
 386                 do_div(tmp, (u32) SRC);
 387                 DST = (u32) tmp;
 388                 CONT;
 389         ALU64_DIV_K:
 390                 do_div(DST, IMM);
 391                 CONT;
 392         ALU_DIV_K:
 393                 tmp = (u32) DST;
 394                 do_div(tmp, (u32) IMM);
 395                 DST = (u32) tmp;
 396                 CONT;
 397         ALU_END_TO_BE:
 398                 switch (IMM) {
 399                 case 16:
 400                         DST = (__force u16) cpu_to_be16(DST);
 401                         break;
 402                 case 32:
 403                         DST = (__force u32) cpu_to_be32(DST);
 404                         break;
 405                 case 64:
 406                         DST = (__force u64) cpu_to_be64(DST);
 407                         break;
 408                 }
 409                 CONT;
 410         ALU_END_TO_LE:
 411                 switch (IMM) {
 412                 case 16:
 413                         DST = (__force u16) cpu_to_le16(DST);
 414                         break;
 415                 case 32:
 416                         DST = (__force u32) cpu_to_le32(DST);
 417                         break;
 418                 case 64:
 419                         DST = (__force u64) cpu_to_le64(DST);
 420                         break;
 421                 }
 422                 CONT;
 423
 424         /* CALL */
 425         JMP_CALL:
 426                 /* Function call scratches BPF_R1-BPF_R5 registers,
 427                  * preserves BPF_R6-BPF_R9, and stores return value
 428                  * into BPF_R0.
 429                  */
 430                 BPF_R0 = (__bpf_call_base + insn->imm)(BPF_R1, BPF_R2, BPF_R3,
 431                                                        BPF_R4, BPF_R5);
 432                 CONT;
 433
 434         /* JMP */
 435         JMP_JA:
 436                 insn += insn->off;
 437                 CONT;
 438         JMP_JEQ_X:
 439                 if (DST == SRC) {
 440                         insn += insn->off;
 441                         CONT_JMP;
 442                 }
 443                 CONT;
 444         JMP_JEQ_K:
 445                 if (DST == IMM) {
 446                         insn += insn->off;
 447                         CONT_JMP;
 448                 }
 449                 CONT;
 450         JMP_JNE_X:
 451                 if (DST != SRC) {
 452                         insn += insn->off;
 453                         CONT_JMP;
 454                 }
 455                 CONT;
 456         JMP_JNE_K:
 457                 if (DST != IMM) {
 458                         insn += insn->off;
 459                         CONT_JMP;
 460                 }
 461                 CONT;
 462         JMP_JGT_X:
 463                 if (DST > SRC) {
 464                         insn += insn->off;
 465                         CONT_JMP;
 466                 }
 467                 CONT;
 468         JMP_JGT_K:
 469                 if (DST > IMM) {
 470                         insn += insn->off;
 471                         CONT_JMP;
 472                 }
 473                 CONT;
 474         JMP_JGE_X:
 475                 if (DST >= SRC) {
 476                         insn += insn->off;
 477                         CONT_JMP;
 478                 }
 479                 CONT;
 480         JMP_JGE_K:
 481                 if (DST >= IMM) {
 482                         insn += insn->off;
 483                         CONT_JMP;
 484                 }
 485                 CONT;
 486         JMP_JSGT_X:
 487                 if (((s64) DST) > ((s64) SRC)) {
 488                         insn += insn->off;
 489                         CONT_JMP;
 490                 }
 491                 CONT;
 492         JMP_JSGT_K:
 493                 if (((s64) DST) > ((s64) IMM)) {
 494                         insn += insn->off;
 495                         CONT_JMP;
 496                 }
 497                 CONT;
 498         JMP_JSGE_X:
 499                 if (((s64) DST) >= ((s64) SRC)) {
 500                         insn += insn->off;
 501                         CONT_JMP;
 502                 }
 503                 CONT;
 504         JMP_JSGE_K:
 505                 if (((s64) DST) >= ((s64) IMM)) {
 506                         insn += insn->off;
 507                         CONT_JMP;
 508                 }
 509                 CONT;
 510         JMP_JSET_X:
 511                 if (DST & SRC) {
 512                         insn += insn->off;
 513                         CONT_JMP;
 514                 }
 515                 CONT;
 516         JMP_JSET_K:
 517                 if (DST & IMM) {
 518                         insn += insn->off;
 519                         CONT_JMP;
 520                 }
 521                 CONT;
 522         JMP_EXIT:
 523                 return BPF_R0;
 524
 525         /* STX and ST and LDX*/
 526 #define LDST(SIZEOP, SIZE)                                              \
 527         STX_MEM_##SIZEOP:                                               \
 528                 *(SIZE *)(unsigned long) (DST + insn->off) = SRC;       \
 529                 CONT;                                                   \
 530         ST_MEM_##SIZEOP:                                                \
 531                 *(SIZE *)(unsigned long) (DST + insn->off) = IMM;       \
 532                 CONT;                                                   \
 533         LDX_MEM_##SIZEOP:                                               \
 534                 DST = *(SIZE *)(unsigned long) (SRC + insn->off);       \
 535                 CONT;
 536
 537         LDST(B,   u8)
 538         LDST(H,  u16)
 539         LDST(W,  u32)
 540         LDST(DW, u64)
 541 #undef LDST
 542         STX_XADD_W: /* lock xadd *(u32 *)(dst_reg + off16) += src_reg */
 543                 atomic_add((u32) SRC, (atomic_t *)(unsigned long)
 544                            (DST + insn->off));
 545                 CONT;
 546         STX_XADD_DW: /* lock xadd *(u64 *)(dst_reg + off16) += src_reg */
 547                 atomic64_add((u64) SRC, (atomic64_t *)(unsigned long)
 548                              (DST + insn->off));
 549                 CONT;
 550         LD_ABS_W: /* BPF_R0 = ntohl(*(u32 *) (skb->data + imm32)) */
 551                 off = IMM;
 552 load_word:
 553                 /* BPF_LD + BPD_ABS and BPF_LD + BPF_IND insns are
 554                  * only appearing in the programs where ctx ==
 555                  * skb. All programs keep 'ctx' in regs[BPF_REG_CTX]
 556                  * == BPF_R6, bpf_convert_filter() saves it in BPF_R6,
 557                  * internal BPF verifier will check that BPF_R6 ==
 558                  * ctx.
 559                  *
 560                  * BPF_ABS and BPF_IND are wrappers of function calls,
 561                  * so they scratch BPF_R1-BPF_R5 registers, preserve
 562                  * BPF_R6-BPF_R9, and store return value into BPF_R0.
 563                  *
 564                  * Implicit input:
 565                  *   ctx == skb == BPF_R6 == CTX
 566                  *
 567                  * Explicit input:
 568                  *   SRC == any register
 569                  *   IMM == 32-bit immediate
 570                  *
 571                  * Output:
 572                  *   BPF_R0 - 8/16/32-bit skb data converted to cpu endianness
 573                  */
 574
 575                 ptr = bpf_load_pointer((struct sk_buff *) (unsigned long) CTX, off, 4, &tmp);
 576                 if (likely(ptr != NULL)) {
 577                         BPF_R0 = get_unaligned_be32(ptr);
 578                         CONT;
 579                 }
 580
 581                 return 0;
 582         LD_ABS_H: /* BPF_R0 = ntohs(*(u16 *) (skb->data + imm32)) */
 583                 off = IMM;
 584 load_half:
 585                 ptr = bpf_load_pointer((struct sk_buff *) (unsigned long) CTX, off, 2, &tmp);
 586                 if (likely(ptr != NULL)) {
 587                         BPF_R0 = get_unaligned_be16(ptr);
 588                         CONT;
 589                 }
 590
 591                 return 0;
 592         LD_ABS_B: /* BPF_R0 = *(u8 *) (skb->data + imm32) */
 593                 off = IMM;
 594 load_byte:
 595                 ptr = bpf_load_pointer((struct sk_buff *) (unsigned long) CTX, off, 1, &tmp);
 596                 if (likely(ptr != NULL)) {
 597                         BPF_R0 = *(u8 *)ptr;
 598                         CONT;
 599                 }
 600
 601                 return 0;
 602         LD_IND_W: /* BPF_R0 = ntohl(*(u32 *) (skb->data + src_reg + imm32)) */
 603                 off = IMM + SRC;
 604                 goto load_word;
 605         LD_IND_H: /* BPF_R0 = ntohs(*(u16 *) (skb->data + src_reg + imm32)) */
 606                 off = IMM + SRC;
 607                 goto load_half;
 608         LD_IND_B: /* BPF_R0 = *(u8 *) (skb->data + src_reg + imm32) */
 609                 off = IMM + SRC;
 610                 goto load_byte;
 611
 612         default_label:
 613                 /* If we ever reach this, we have a bug somewhere. */
 614                 WARN_RATELIMIT(1, "unknown opcode %02x\n", insn->code);
 615                 return 0;
 616 }
 617
 618 void __weak bpf_int_jit_compile(struct bpf_prog *prog)
 619 {
 620 }
 621
 622 /**
 623  *      bpf_prog_select_runtime - select execution runtime for BPF program
 624  *      @fp: bpf_prog populated with internal BPF program
 625  *
 626  * try to JIT internal BPF program, if JIT is not available select interpreter
 627  * BPF program will be executed via BPF_PROG_RUN() macro
 628  */
 629 void bpf_prog_select_runtime(struct bpf_prog *fp)
 630 {
 631         fp->bpf_func = (void *) __bpf_prog_run;
 632
 633         /* Probe if internal BPF can be JITed */
 634         bpf_int_jit_compile(fp);
 635         /* Lock whole bpf_prog as read-only */
 636         bpf_prog_lock_ro(fp);
 637 }
 638 EXPORT_SYMBOL_GPL(bpf_prog_select_runtime);
 639
 640 static void bpf_prog_free_deferred(struct work_struct *work)
 641 {
 642         struct bpf_prog_aux *aux;
 643
 644         aux = container_of(work, struct bpf_prog_aux, work);
 645         bpf_jit_free(aux->prog);
 646 }
 647
 648 /* Free internal BPF program */
 649 void bpf_prog_free(struct bpf_prog *fp)
 650 {
 651         struct bpf_prog_aux *aux = fp->aux;
 652
 653         INIT_WORK(&aux->work, bpf_prog_free_deferred);
 654         aux->prog = fp;
 655         schedule_work(&aux->work);
 656 }
 657 EXPORT_SYMBOL_GPL(bpf_prog_free);
 658
 659 /* To execute LD_ABS/LD_IND instructions __bpf_prog_run() may call
 660  * skb_copy_bits(), so provide a weak definition of it for NET-less config.
 661  */
 662 int __weak skb_copy_bits(const struct sk_buff *skb, int offset, void *to,
 663                          int len)
 664 {
 665         return -EFAULT;
 666 }