include/linux/filter.h

   1 /*
   2  * Linux Socket Filter Data Structures
   3  */
   4 #ifndef __LINUX_FILTER_H__
   5 #define __LINUX_FILTER_H__
   6
   7 #include <stdarg.h>
   8
   9 #include <linux/atomic.h>
  10 #include <linux/compat.h>
  11 #include <linux/skbuff.h>
  12 #include <linux/linkage.h>
  13 #include <linux/printk.h>
  14 #include <linux/workqueue.h>
  15
  16 #include <asm/cacheflush.h>
  17
  18 #include <uapi/linux/filter.h>
  19 #include <uapi/linux/bpf.h>
  20
  21 struct sk_buff;
  22 struct sock;
  23 struct seccomp_data;
  24 struct bpf_prog_aux;
  25
  26 /* ArgX, context and stack frame pointer register positions. Note,
  27  * Arg1, Arg2, Arg3, etc are used as argument mappings of function
  28  * calls in BPF_CALL instruction.
  29  */
  30 #define BPF_REG_ARG1    BPF_REG_1
  31 #define BPF_REG_ARG2    BPF_REG_2
  32 #define BPF_REG_ARG3    BPF_REG_3
  33 #define BPF_REG_ARG4    BPF_REG_4
  34 #define BPF_REG_ARG5    BPF_REG_5
  35 #define BPF_REG_CTX     BPF_REG_6
  36 #define BPF_REG_FP      BPF_REG_10
  37
  38 /* Additional register mappings for converted user programs. */
  39 #define BPF_REG_A       BPF_REG_0
  40 #define BPF_REG_X       BPF_REG_7
  41 #define BPF_REG_TMP     BPF_REG_8
  42
  43 /* BPF program can access up to 512 bytes of stack space. */
  44 #define MAX_BPF_STACK   512
  45
  46 /* Helper macros for filter block array initializers. */
  47
  48 /* ALU ops on registers, bpf_add|sub|...: dst_reg += src_reg */
  49
  50 #define BPF_ALU64_REG(OP, DST, SRC)                             \
  51         ((struct bpf_insn) {                                    \
  52                 .code  = BPF_ALU64 | BPF_OP(OP) | BPF_X,        \
  53                 .dst_reg = DST,                                 \
  54                 .src_reg = SRC,                                 \
  55                 .off   = 0,                                     \
  56                 .imm   = 0 })
  57
  58 #define BPF_ALU32_REG(OP, DST, SRC)                             \
  59         ((struct bpf_insn) {                                    \
  60                 .code  = BPF_ALU | BPF_OP(OP) | BPF_X,          \
  61                 .dst_reg = DST,                                 \
  62                 .src_reg = SRC,                                 \
  63                 .off   = 0,                                     \
  64                 .imm   = 0 })
  65
  66 /* ALU ops on immediates, bpf_add|sub|...: dst_reg += imm32 */
  67
  68 #define BPF_ALU64_IMM(OP, DST, IMM)                             \
  69         ((struct bpf_insn) {                                    \
  70                 .code  = BPF_ALU64 | BPF_OP(OP) | BPF_K,        \
  71                 .dst_reg = DST,                                 \
  72                 .src_reg = 0,                                   \
  73                 .off   = 0,                                     \
  74                 .imm   = IMM })
  75
  76 #define BPF_ALU32_IMM(OP, DST, IMM)                             \
  77         ((struct bpf_insn) {                                    \
  78                 .code  = BPF_ALU | BPF_OP(OP) | BPF_K,          \
  79                 .dst_reg = DST,                                 \
  80                 .src_reg = 0,                                   \
  81                 .off   = 0,                                     \
  82                 .imm   = IMM })
  83
  84 /* Endianess conversion, cpu_to_{l,b}e(), {l,b}e_to_cpu() */
  85
  86 #define BPF_ENDIAN(TYPE, DST, LEN)                              \
  87         ((struct bpf_insn) {                                    \
  88                 .code  = BPF_ALU | BPF_END | BPF_SRC(TYPE),     \
  89                 .dst_reg = DST,                                 \
  90                 .src_reg = 0,                                   \
  91                 .off   = 0,                                     \
  92                 .imm   = LEN })
  93
  94 /* Short form of mov, dst_reg = src_reg */
  95
  96 #define BPF_MOV64_REG(DST, SRC)                                 \
  97         ((struct bpf_insn) {                                    \
  98                 .code  = BPF_ALU64 | BPF_MOV | BPF_X,           \
  99                 .dst_reg = DST,                                 \
 100                 .src_reg = SRC,                                 \
 101                 .off   = 0,                                     \
 102                 .imm   = 0 })
 103
 104 #define BPF_MOV32_REG(DST, SRC)                                 \
 105         ((struct bpf_insn) {                                    \
 106                 .code  = BPF_ALU | BPF_MOV | BPF_X,             \
 107                 .dst_reg = DST,                                 \
 108                 .src_reg = SRC,                                 \
 109                 .off   = 0,                                     \
 110                 .imm   = 0 })
 111
 112 /* Short form of mov, dst_reg = imm32 */
 113
 114 #define BPF_MOV64_IMM(DST, IMM)                                 \
 115         ((struct bpf_insn) {                                    \
 116                 .code  = BPF_ALU64 | BPF_MOV | BPF_K,           \
 117                 .dst_reg = DST,                                 \
 118                 .src_reg = 0,                                   \
 119                 .off   = 0,                                     \
 120                 .imm   = IMM })
 121
 122 #define BPF_MOV32_IMM(DST, IMM)                                 \
 123         ((struct bpf_insn) {                                    \
 124                 .code  = BPF_ALU | BPF_MOV | BPF_K,             \
 125                 .dst_reg = DST,                                 \
 126                 .src_reg = 0,                                   \
 127                 .off   = 0,                                     \
 128                 .imm   = IMM })
 129
 130 /* BPF_LD_IMM64 macro encodes single 'load 64-bit immediate' insn */
 131 #define BPF_LD_IMM64(DST, IMM)                                  \
 132         BPF_LD_IMM64_RAW(DST, 0, IMM)
 133
 134 #define BPF_LD_IMM64_RAW(DST, SRC, IMM)                         \
 135         ((struct bpf_insn) {                                    \
 136                 .code  = BPF_LD | BPF_DW | BPF_IMM,             \
 137                 .dst_reg = DST,                                 \
 138                 .src_reg = SRC,                                 \
 139                 .off   = 0,                                     \
 140                 .imm   = (__u32) (IMM) }),                      \
 141         ((struct bpf_insn) {                                    \
 142                 .code  = 0, /* zero is reserved opcode */       \
 143                 .dst_reg = 0,                                   \
 144                 .src_reg = 0,                                   \
 145                 .off   = 0,                                     \
 146                 .imm   = ((__u64) (IMM)) >> 32 })
 147
 148 /* pseudo BPF_LD_IMM64 insn used to refer to process-local map_fd */
 149 #define BPF_LD_MAP_FD(DST, MAP_FD)                              \
 150         BPF_LD_IMM64_RAW(DST, BPF_PSEUDO_MAP_FD, MAP_FD)
 151
 152 /* Short form of mov based on type, BPF_X: dst_reg = src_reg, BPF_K: dst_reg = imm32 */
 153
 154 #define BPF_MOV64_RAW(TYPE, DST, SRC, IMM)                      \
 155         ((struct bpf_insn) {                                    \
 156                 .code  = BPF_ALU64 | BPF_MOV | BPF_SRC(TYPE),   \
 157                 .dst_reg = DST,                                 \
 158                 .src_reg = SRC,                                 \
 159                 .off   = 0,                                     \
 160                 .imm   = IMM })
 161
 162 #define BPF_MOV32_RAW(TYPE, DST, SRC, IMM)                      \
 163         ((struct bpf_insn) {                                    \
 164                 .code  = BPF_ALU | BPF_MOV | BPF_SRC(TYPE),     \
 165                 .dst_reg = DST,                                 \
 166                 .src_reg = SRC,                                 \
 167                 .off   = 0,                                     \
 168                 .imm   = IMM })
 169
 170 /* Direct packet access, R0 = *(uint *) (skb->data + imm32) */
 171
 172 #define BPF_LD_ABS(SIZE, IMM)                                   \
 173         ((struct bpf_insn) {                                    \
 174                 .code  = BPF_LD | BPF_SIZE(SIZE) | BPF_ABS,     \
 175                 .dst_reg = 0,                                   \
 176                 .src_reg = 0,                                   \
 177                 .off   = 0,                                     \
 178                 .imm   = IMM })
 179
 180 /* Indirect packet access, R0 = *(uint *) (skb->data + src_reg + imm32) */
 181
 182 #define BPF_LD_IND(SIZE, SRC, IMM)                              \
 183         ((struct bpf_insn) {                                    \
 184                 .code  = BPF_LD | BPF_SIZE(SIZE) | BPF_IND,     \
 185                 .dst_reg = 0,                                   \
 186                 .src_reg = SRC,                                 \
 187                 .off   = 0,                                     \
 188                 .imm   = IMM })
 189
 190 /* Memory load, dst_reg = *(uint *) (src_reg + off16) */
 191
 192 #define BPF_LDX_MEM(SIZE, DST, SRC, OFF)                        \
 193         ((struct bpf_insn) {                                    \
 194                 .code  = BPF_LDX | BPF_SIZE(SIZE) | BPF_MEM,    \
 195                 .dst_reg = DST,                                 \
 196                 .src_reg = SRC,                                 \
 197                 .off   = OFF,                                   \
 198                 .imm   = 0 })
 199
 200 /* Memory store, *(uint *) (dst_reg + off16) = src_reg */
 201
 202 #define BPF_STX_MEM(SIZE, DST, SRC, OFF)                        \
 203         ((struct bpf_insn) {                                    \
 204                 .code  = BPF_STX | BPF_SIZE(SIZE) | BPF_MEM,    \
 205                 .dst_reg = DST,                                 \
 206                 .src_reg = SRC,                                 \
 207                 .off   = OFF,                                   \
 208                 .imm   = 0 })
 209
 210 /* Atomic memory add, *(uint *)(dst_reg + off16) += src_reg */
 211
 212 #define BPF_STX_XADD(SIZE, DST, SRC, OFF)                       \
 213         ((struct bpf_insn) {                                    \
 214                 .code  = BPF_STX | BPF_SIZE(SIZE) | BPF_XADD,   \
 215                 .dst_reg = DST,                                 \
 216                 .src_reg = SRC,                                 \
 217                 .off   = OFF,                                   \
 218                 .imm   = 0 })
 219
 220 /* Memory store, *(uint *) (dst_reg + off16) = imm32 */
 221
 222 #define BPF_ST_MEM(SIZE, DST, OFF, IMM)                         \
 223         ((struct bpf_insn) {                                    \
 224                 .code  = BPF_ST | BPF_SIZE(SIZE) | BPF_MEM,     \
 225                 .dst_reg = DST,                                 \
 226                 .src_reg = 0,                                   \
 227                 .off   = OFF,                                   \
 228                 .imm   = IMM })
 229
 230 /* Conditional jumps against registers, if (dst_reg 'op' src_reg) goto pc + off16 */
 231
 232 #define BPF_JMP_REG(OP, DST, SRC, OFF)                          \
 233         ((struct bpf_insn) {                                    \
 234                 .code  = BPF_JMP | BPF_OP(OP) | BPF_X,          \
 235                 .dst_reg = DST,                                 \
 236                 .src_reg = SRC,                                 \
 237                 .off   = OFF,                                   \
 238                 .imm   = 0 })
 239
 240 /* Conditional jumps against immediates, if (dst_reg 'op' imm32) goto pc + off16 */
 241
 242 #define BPF_JMP_IMM(OP, DST, IMM, OFF)                          \
 243         ((struct bpf_insn) {                                    \
 244                 .code  = BPF_JMP | BPF_OP(OP) | BPF_K,          \
 245                 .dst_reg = DST,                                 \
 246                 .src_reg = 0,                                   \
 247                 .off   = OFF,                                   \
 248                 .imm   = IMM })
 249
 250 /* Function call */
 251
 252 #define BPF_EMIT_CALL(FUNC)                                     \
 253         ((struct bpf_insn) {                                    \
 254                 .code  = BPF_JMP | BPF_CALL,                    \
 255                 .dst_reg = 0,                                   \
 256                 .src_reg = 0,                                   \
 257                 .off   = 0,                                     \
 258                 .imm   = ((FUNC) - __bpf_call_base) })
 259
 260 /* Raw code statement block */
 261
 262 #define BPF_RAW_INSN(CODE, DST, SRC, OFF, IMM)                  \
 263         ((struct bpf_insn) {                                    \
 264                 .code  = CODE,                                  \
 265                 .dst_reg = DST,                                 \
 266                 .src_reg = SRC,                                 \
 267                 .off   = OFF,                                   \
 268                 .imm   = IMM })
 269
 270 /* Program exit */
 271
 272 #define BPF_EXIT_INSN()                                         \
 273         ((struct bpf_insn) {                                    \
 274                 .code  = BPF_JMP | BPF_EXIT,                    \
 275                 .dst_reg = 0,                                   \
 276                 .src_reg = 0,                                   \
 277                 .off   = 0,                                     \
 278                 .imm   = 0 })
 279
 280 /* Internal classic blocks for direct assignment */
 281
 282 #define __BPF_STMT(CODE, K)                                     \
 283         ((struct sock_filter) BPF_STMT(CODE, K))
 284
 285 #define __BPF_JUMP(CODE, K, JT, JF)                             \
 286         ((struct sock_filter) BPF_JUMP(CODE, K, JT, JF))
 287
 288 #define bytes_to_bpf_size(bytes)                                \
 289 ({                                                              \
 290         int bpf_size = -EINVAL;                                 \
 291                                                                 \
 292         if (bytes == sizeof(u8))                                \
 293                 bpf_size = BPF_B;                               \
 294         else if (bytes == sizeof(u16))                          \
 295                 bpf_size = BPF_H;                               \
 296         else if (bytes == sizeof(u32))                          \
 297                 bpf_size = BPF_W;                               \
 298         else if (bytes == sizeof(u64))                          \
 299                 bpf_size = BPF_DW;                              \
 300                                                                 \
 301         bpf_size;                                               \
 302 })
 303
 304 /* Macro to invoke filter function. */
 305 #define SK_RUN_FILTER(filter, ctx) \
 306         (*filter->prog->bpf_func)(ctx, filter->prog->insnsi)
 307
 308 #ifdef CONFIG_COMPAT
 309 /* A struct sock_filter is architecture independent. */
 310 struct compat_sock_fprog {
 311         u16             len;
 312         compat_uptr_t   filter; /* struct sock_filter * */
 313 };
 314 #endif
 315
 316 struct sock_fprog_kern {
 317         u16                     len;
 318         struct sock_filter      *filter;
 319 };
 320
 321 struct bpf_binary_header {
 322         unsigned int pages;
 323         u8 image[];
 324 };
 325
 326 struct bpf_prog {
 327         u16                     pages;          /* Number of allocated pages */
 328         bool                    jited;          /* Is our filter JIT'ed? */
 329         bool                    gpl_compatible; /* Is our filter GPL compatible? */
 330         u32                     len;            /* Number of filter blocks */
 331         enum bpf_prog_type      type;           /* Type of BPF program */
 332         struct bpf_prog_aux     *aux;           /* Auxiliary fields */
 333         struct sock_fprog_kern  *orig_prog;     /* Original BPF program */
 334         unsigned int            (*bpf_func)(const struct sk_buff *skb,
 335                                             const struct bpf_insn *filter);
 336         /* Instructions for interpreter */
 337         union {
 338                 struct sock_filter      insns[0];
 339                 struct bpf_insn         insnsi[0];
 340         };
 341 };
 342
 343 struct sk_filter {
 344         atomic_t        refcnt;
 345         struct rcu_head rcu;
 346         struct bpf_prog *prog;
 347 };
 348
 349 #define BPF_PROG_RUN(filter, ctx)  (*filter->bpf_func)(ctx, filter->insnsi)
 350
 351 static inline unsigned int bpf_prog_size(unsigned int proglen)
 352 {
 353         return max(sizeof(struct bpf_prog),
 354                    offsetof(struct bpf_prog, insns[proglen]));
 355 }
 356
 357 #define bpf_classic_proglen(fprog) (fprog->len * sizeof(fprog->filter[0]))
 358
 359 #ifdef CONFIG_DEBUG_SET_MODULE_RONX
 360 static inline void bpf_prog_lock_ro(struct bpf_prog *fp)
 361 {
 362         set_memory_ro((unsigned long)fp, fp->pages);
 363 }
 364
 365 static inline void bpf_prog_unlock_ro(struct bpf_prog *fp)
 366 {
 367         set_memory_rw((unsigned long)fp, fp->pages);
 368 }
 369 #else
 370 static inline void bpf_prog_lock_ro(struct bpf_prog *fp)
 371 {
 372 }
 373
 374 static inline void bpf_prog_unlock_ro(struct bpf_prog *fp)
 375 {
 376 }
 377 #endif /* CONFIG_DEBUG_SET_MODULE_RONX */
 378
 379 int sk_filter(struct sock *sk, struct sk_buff *skb);
 380
 381 int bpf_prog_select_runtime(struct bpf_prog *fp);
 382 void bpf_prog_free(struct bpf_prog *fp);
 383
 384 struct bpf_prog *bpf_prog_alloc(unsigned int size, gfp_t gfp_extra_flags);
 385 struct bpf_prog *bpf_prog_realloc(struct bpf_prog *fp_old, unsigned int size,
 386                                   gfp_t gfp_extra_flags);
 387 void __bpf_prog_free(struct bpf_prog *fp);
 388
 389 static inline void bpf_prog_unlock_free(struct bpf_prog *fp)
 390 {
 391         bpf_prog_unlock_ro(fp);
 392         __bpf_prog_free(fp);
 393 }
 394
 395 typedef int (*bpf_aux_classic_check_t)(struct sock_filter *filter,
 396                                        unsigned int flen);
 397
 398 int bpf_prog_create(struct bpf_prog **pfp, struct sock_fprog_kern *fprog);
 399 int bpf_prog_create_from_user(struct bpf_prog **pfp, struct sock_fprog *fprog,
 400                               bpf_aux_classic_check_t trans);
 401 void bpf_prog_destroy(struct bpf_prog *fp);
 402
 403 int sk_attach_filter(struct sock_fprog *fprog, struct sock *sk);
 404 int sk_attach_bpf(u32 ufd, struct sock *sk);
 405 int sk_detach_filter(struct sock *sk);
 406 int sk_get_filter(struct sock *sk, struct sock_filter __user *filter,
 407                   unsigned int len);
 408
 409 bool sk_filter_charge(struct sock *sk, struct sk_filter *fp);
 410 void sk_filter_uncharge(struct sock *sk, struct sk_filter *fp);
 411
 412 u64 __bpf_call_base(u64 r1, u64 r2, u64 r3, u64 r4, u64 r5);
 413 void bpf_int_jit_compile(struct bpf_prog *fp);
 414
 415 #ifdef CONFIG_BPF_JIT
 416 typedef void (*bpf_jit_fill_hole_t)(void *area, unsigned int size);
 417
 418 struct bpf_binary_header *
 419 bpf_jit_binary_alloc(unsigned int proglen, u8 **image_ptr,
 420                      unsigned int alignment,
 421                      bpf_jit_fill_hole_t bpf_fill_ill_insns);
 422 void bpf_jit_binary_free(struct bpf_binary_header *hdr);
 423
 424 void bpf_jit_compile(struct bpf_prog *fp);
 425 void bpf_jit_free(struct bpf_prog *fp);
 426
 427 static inline void bpf_jit_dump(unsigned int flen, unsigned int proglen,
 428                                 u32 pass, void *image)
 429 {
 430         pr_err("flen=%u proglen=%u pass=%u image=%pK\n",
 431                flen, proglen, pass, image);
 432         if (image)
 433                 print_hex_dump(KERN_ERR, "JIT code: ", DUMP_PREFIX_OFFSET,
 434                                16, 1, image, proglen, false);
 435 }
 436 #else
 437 static inline void bpf_jit_compile(struct bpf_prog *fp)
 438 {
 439 }
 440
 441 static inline void bpf_jit_free(struct bpf_prog *fp)
 442 {
 443         bpf_prog_unlock_free(fp);
 444 }
 445 #endif /* CONFIG_BPF_JIT */
 446
 447 #define BPF_ANC         BIT(15)
 448
 449 static inline u16 bpf_anc_helper(const struct sock_filter *ftest)
 450 {
 451         BUG_ON(ftest->code & BPF_ANC);
 452
 453         switch (ftest->code) {
 454         case BPF_LD | BPF_W | BPF_ABS:
 455         case BPF_LD | BPF_H | BPF_ABS:
 456         case BPF_LD | BPF_B | BPF_ABS:
 457 #define BPF_ANCILLARY(CODE)     case SKF_AD_OFF + SKF_AD_##CODE:        \
 458                                 return BPF_ANC | SKF_AD_##CODE
 459                 switch (ftest->k) {
 460                 BPF_ANCILLARY(PROTOCOL);
 461                 BPF_ANCILLARY(PKTTYPE);
 462                 BPF_ANCILLARY(IFINDEX);
 463                 BPF_ANCILLARY(NLATTR);
 464                 BPF_ANCILLARY(NLATTR_NEST);
 465                 BPF_ANCILLARY(MARK);
 466                 BPF_ANCILLARY(QUEUE);
 467                 BPF_ANCILLARY(HATYPE);
 468                 BPF_ANCILLARY(RXHASH);
 469                 BPF_ANCILLARY(CPU);
 470                 BPF_ANCILLARY(ALU_XOR_X);
 471                 BPF_ANCILLARY(VLAN_TAG);
 472                 BPF_ANCILLARY(VLAN_TAG_PRESENT);
 473                 BPF_ANCILLARY(PAY_OFFSET);
 474                 BPF_ANCILLARY(RANDOM);
 475                 BPF_ANCILLARY(VLAN_TPID);
 476                 }
 477                 /* Fallthrough. */
 478         default:
 479                 return ftest->code;
 480         }
 481 }
 482
 483 void *bpf_internal_load_pointer_neg_helper(const struct sk_buff *skb,
 484                                            int k, unsigned int size);
 485
 486 static inline void *bpf_load_pointer(const struct sk_buff *skb, int k,
 487                                      unsigned int size, void *buffer)
 488 {
 489         if (k >= 0)
 490                 return skb_header_pointer(skb, k, size, buffer);
 491
 492         return bpf_internal_load_pointer_neg_helper(skb, k, size);
 493 }
 494
 495 static inline int bpf_tell_extensions(void)
 496 {
 497         return SKF_AD_MAX;
 498 }
 499
 500 #endif /* __LINUX_FILTER_H__ */