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 #define BPF_PSEUDO_MAP_FD       1
 149
 150 /* pseudo BPF_LD_IMM64 insn used to refer to process-local map_fd */
 151 #define BPF_LD_MAP_FD(DST, MAP_FD)                              \
 152         BPF_LD_IMM64_RAW(DST, BPF_PSEUDO_MAP_FD, MAP_FD)
 153
 154 /* Short form of mov based on type, BPF_X: dst_reg = src_reg, BPF_K: dst_reg = imm32 */
 155
 156 #define BPF_MOV64_RAW(TYPE, DST, SRC, IMM)                      \
 157         ((struct bpf_insn) {                                    \
 158                 .code  = BPF_ALU64 | BPF_MOV | BPF_SRC(TYPE),   \
 159                 .dst_reg = DST,                                 \
 160                 .src_reg = SRC,                                 \
 161                 .off   = 0,                                     \
 162                 .imm   = IMM })
 163
 164 #define BPF_MOV32_RAW(TYPE, DST, SRC, IMM)                      \
 165         ((struct bpf_insn) {                                    \
 166                 .code  = BPF_ALU | BPF_MOV | BPF_SRC(TYPE),     \
 167                 .dst_reg = DST,                                 \
 168                 .src_reg = SRC,                                 \
 169                 .off   = 0,                                     \
 170                 .imm   = IMM })
 171
 172 /* Direct packet access, R0 = *(uint *) (skb->data + imm32) */
 173
 174 #define BPF_LD_ABS(SIZE, IMM)                                   \
 175         ((struct bpf_insn) {                                    \
 176                 .code  = BPF_LD | BPF_SIZE(SIZE) | BPF_ABS,     \
 177                 .dst_reg = 0,                                   \
 178                 .src_reg = 0,                                   \
 179                 .off   = 0,                                     \
 180                 .imm   = IMM })
 181
 182 /* Indirect packet access, R0 = *(uint *) (skb->data + src_reg + imm32) */
 183
 184 #define BPF_LD_IND(SIZE, SRC, IMM)                              \
 185         ((struct bpf_insn) {                                    \
 186                 .code  = BPF_LD | BPF_SIZE(SIZE) | BPF_IND,     \
 187                 .dst_reg = 0,                                   \
 188                 .src_reg = SRC,                                 \
 189                 .off   = 0,                                     \
 190                 .imm   = IMM })
 191
 192 /* Memory load, dst_reg = *(uint *) (src_reg + off16) */
 193
 194 #define BPF_LDX_MEM(SIZE, DST, SRC, OFF)                        \
 195         ((struct bpf_insn) {                                    \
 196                 .code  = BPF_LDX | BPF_SIZE(SIZE) | BPF_MEM,    \
 197                 .dst_reg = DST,                                 \
 198                 .src_reg = SRC,                                 \
 199                 .off   = OFF,                                   \
 200                 .imm   = 0 })
 201
 202 /* Memory store, *(uint *) (dst_reg + off16) = src_reg */
 203
 204 #define BPF_STX_MEM(SIZE, DST, SRC, OFF)                        \
 205         ((struct bpf_insn) {                                    \
 206                 .code  = BPF_STX | BPF_SIZE(SIZE) | BPF_MEM,    \
 207                 .dst_reg = DST,                                 \
 208                 .src_reg = SRC,                                 \
 209                 .off   = OFF,                                   \
 210                 .imm   = 0 })
 211
 212 /* Memory store, *(uint *) (dst_reg + off16) = imm32 */
 213
 214 #define BPF_ST_MEM(SIZE, DST, OFF, IMM)                         \
 215         ((struct bpf_insn) {                                    \
 216                 .code  = BPF_ST | BPF_SIZE(SIZE) | BPF_MEM,     \
 217                 .dst_reg = DST,                                 \
 218                 .src_reg = 0,                                   \
 219                 .off   = OFF,                                   \
 220                 .imm   = IMM })
 221
 222 /* Conditional jumps against registers, if (dst_reg 'op' src_reg) goto pc + off16 */
 223
 224 #define BPF_JMP_REG(OP, DST, SRC, OFF)                          \
 225         ((struct bpf_insn) {                                    \
 226                 .code  = BPF_JMP | BPF_OP(OP) | BPF_X,          \
 227                 .dst_reg = DST,                                 \
 228                 .src_reg = SRC,                                 \
 229                 .off   = OFF,                                   \
 230                 .imm   = 0 })
 231
 232 /* Conditional jumps against immediates, if (dst_reg 'op' imm32) goto pc + off16 */
 233
 234 #define BPF_JMP_IMM(OP, DST, IMM, OFF)                          \
 235         ((struct bpf_insn) {                                    \
 236                 .code  = BPF_JMP | BPF_OP(OP) | BPF_K,          \
 237                 .dst_reg = DST,                                 \
 238                 .src_reg = 0,                                   \
 239                 .off   = OFF,                                   \
 240                 .imm   = IMM })
 241
 242 /* Function call */
 243
 244 #define BPF_EMIT_CALL(FUNC)                                     \
 245         ((struct bpf_insn) {                                    \
 246                 .code  = BPF_JMP | BPF_CALL,                    \
 247                 .dst_reg = 0,                                   \
 248                 .src_reg = 0,                                   \
 249                 .off   = 0,                                     \
 250                 .imm   = ((FUNC) - __bpf_call_base) })
 251
 252 /* Raw code statement block */
 253
 254 #define BPF_RAW_INSN(CODE, DST, SRC, OFF, IMM)                  \
 255         ((struct bpf_insn) {                                    \
 256                 .code  = CODE,                                  \
 257                 .dst_reg = DST,                                 \
 258                 .src_reg = SRC,                                 \
 259                 .off   = OFF,                                   \
 260                 .imm   = IMM })
 261
 262 /* Program exit */
 263
 264 #define BPF_EXIT_INSN()                                         \
 265         ((struct bpf_insn) {                                    \
 266                 .code  = BPF_JMP | BPF_EXIT,                    \
 267                 .dst_reg = 0,                                   \
 268                 .src_reg = 0,                                   \
 269                 .off   = 0,                                     \
 270                 .imm   = 0 })
 271
 272 #define bytes_to_bpf_size(bytes)                                \
 273 ({                                                              \
 274         int bpf_size = -EINVAL;                                 \
 275                                                                 \
 276         if (bytes == sizeof(u8))                                \
 277                 bpf_size = BPF_B;                               \
 278         else if (bytes == sizeof(u16))                          \
 279                 bpf_size = BPF_H;                               \
 280         else if (bytes == sizeof(u32))                          \
 281                 bpf_size = BPF_W;                               \
 282         else if (bytes == sizeof(u64))                          \
 283                 bpf_size = BPF_DW;                              \
 284                                                                 \
 285         bpf_size;                                               \
 286 })
 287
 288 /* Macro to invoke filter function. */
 289 #define SK_RUN_FILTER(filter, ctx) \
 290         (*filter->prog->bpf_func)(ctx, filter->prog->insnsi)
 291
 292 #ifdef CONFIG_COMPAT
 293 /* A struct sock_filter is architecture independent. */
 294 struct compat_sock_fprog {
 295         u16             len;
 296         compat_uptr_t   filter; /* struct sock_filter * */
 297 };
 298 #endif
 299
 300 struct sock_fprog_kern {
 301         u16                     len;
 302         struct sock_filter      *filter;
 303 };
 304
 305 struct bpf_binary_header {
 306         unsigned int pages;
 307         u8 image[];
 308 };
 309
 310 struct bpf_prog {
 311         u16                     pages;          /* Number of allocated pages */
 312         bool                    jited;          /* Is our filter JIT'ed? */
 313         u32                     len;            /* Number of filter blocks */
 314         struct sock_fprog_kern  *orig_prog;     /* Original BPF program */
 315         struct bpf_prog_aux     *aux;           /* Auxiliary fields */
 316         unsigned int            (*bpf_func)(const struct sk_buff *skb,
 317                                             const struct bpf_insn *filter);
 318         /* Instructions for interpreter */
 319         union {
 320                 struct sock_filter      insns[0];
 321                 struct bpf_insn         insnsi[0];
 322         };
 323 };
 324
 325 struct sk_filter {
 326         atomic_t        refcnt;
 327         struct rcu_head rcu;
 328         struct bpf_prog *prog;
 329 };
 330
 331 #define BPF_PROG_RUN(filter, ctx)  (*filter->bpf_func)(ctx, filter->insnsi)
 332
 333 static inline unsigned int bpf_prog_size(unsigned int proglen)
 334 {
 335         return max(sizeof(struct bpf_prog),
 336                    offsetof(struct bpf_prog, insns[proglen]));
 337 }
 338
 339 #define bpf_classic_proglen(fprog) (fprog->len * sizeof(fprog->filter[0]))
 340
 341 #ifdef CONFIG_DEBUG_SET_MODULE_RONX
 342 static inline void bpf_prog_lock_ro(struct bpf_prog *fp)
 343 {
 344         set_memory_ro((unsigned long)fp, fp->pages);
 345 }
 346
 347 static inline void bpf_prog_unlock_ro(struct bpf_prog *fp)
 348 {
 349         set_memory_rw((unsigned long)fp, fp->pages);
 350 }
 351 #else
 352 static inline void bpf_prog_lock_ro(struct bpf_prog *fp)
 353 {
 354 }
 355
 356 static inline void bpf_prog_unlock_ro(struct bpf_prog *fp)
 357 {
 358 }
 359 #endif /* CONFIG_DEBUG_SET_MODULE_RONX */
 360
 361 int sk_filter(struct sock *sk, struct sk_buff *skb);
 362
 363 void bpf_prog_select_runtime(struct bpf_prog *fp);
 364 void bpf_prog_free(struct bpf_prog *fp);
 365
 366 int bpf_convert_filter(struct sock_filter *prog, int len,
 367                        struct bpf_insn *new_prog, int *new_len);
 368
 369 struct bpf_prog *bpf_prog_alloc(unsigned int size, gfp_t gfp_extra_flags);
 370 struct bpf_prog *bpf_prog_realloc(struct bpf_prog *fp_old, unsigned int size,
 371                                   gfp_t gfp_extra_flags);
 372 void __bpf_prog_free(struct bpf_prog *fp);
 373
 374 static inline void bpf_prog_unlock_free(struct bpf_prog *fp)
 375 {
 376         bpf_prog_unlock_ro(fp);
 377         __bpf_prog_free(fp);
 378 }
 379
 380 int bpf_prog_create(struct bpf_prog **pfp, struct sock_fprog_kern *fprog);
 381 void bpf_prog_destroy(struct bpf_prog *fp);
 382
 383 int sk_attach_filter(struct sock_fprog *fprog, struct sock *sk);
 384 int sk_attach_bpf(u32 ufd, struct sock *sk);
 385 int sk_detach_filter(struct sock *sk);
 386
 387 int bpf_check_classic(const struct sock_filter *filter, unsigned int flen);
 388 int sk_get_filter(struct sock *sk, struct sock_filter __user *filter,
 389                   unsigned int len);
 390
 391 bool sk_filter_charge(struct sock *sk, struct sk_filter *fp);
 392 void sk_filter_uncharge(struct sock *sk, struct sk_filter *fp);
 393
 394 u64 __bpf_call_base(u64 r1, u64 r2, u64 r3, u64 r4, u64 r5);
 395 void bpf_int_jit_compile(struct bpf_prog *fp);
 396
 397 #ifdef CONFIG_BPF_JIT
 398 typedef void (*bpf_jit_fill_hole_t)(void *area, unsigned int size);
 399
 400 struct bpf_binary_header *
 401 bpf_jit_binary_alloc(unsigned int proglen, u8 **image_ptr,
 402                      unsigned int alignment,
 403                      bpf_jit_fill_hole_t bpf_fill_ill_insns);
 404 void bpf_jit_binary_free(struct bpf_binary_header *hdr);
 405
 406 void bpf_jit_compile(struct bpf_prog *fp);
 407 void bpf_jit_free(struct bpf_prog *fp);
 408
 409 static inline void bpf_jit_dump(unsigned int flen, unsigned int proglen,
 410                                 u32 pass, void *image)
 411 {
 412         pr_err("flen=%u proglen=%u pass=%u image=%pK\n",
 413                flen, proglen, pass, image);
 414         if (image)
 415                 print_hex_dump(KERN_ERR, "JIT code: ", DUMP_PREFIX_OFFSET,
 416                                16, 1, image, proglen, false);
 417 }
 418 #else
 419 static inline void bpf_jit_compile(struct bpf_prog *fp)
 420 {
 421 }
 422
 423 static inline void bpf_jit_free(struct bpf_prog *fp)
 424 {
 425         bpf_prog_unlock_free(fp);
 426 }
 427 #endif /* CONFIG_BPF_JIT */
 428
 429 #define BPF_ANC         BIT(15)
 430
 431 static inline u16 bpf_anc_helper(const struct sock_filter *ftest)
 432 {
 433         BUG_ON(ftest->code & BPF_ANC);
 434
 435         switch (ftest->code) {
 436         case BPF_LD | BPF_W | BPF_ABS:
 437         case BPF_LD | BPF_H | BPF_ABS:
 438         case BPF_LD | BPF_B | BPF_ABS:
 439 #define BPF_ANCILLARY(CODE)     case SKF_AD_OFF + SKF_AD_##CODE:        \
 440                                 return BPF_ANC | SKF_AD_##CODE
 441                 switch (ftest->k) {
 442                 BPF_ANCILLARY(PROTOCOL);
 443                 BPF_ANCILLARY(PKTTYPE);
 444                 BPF_ANCILLARY(IFINDEX);
 445                 BPF_ANCILLARY(NLATTR);
 446                 BPF_ANCILLARY(NLATTR_NEST);
 447                 BPF_ANCILLARY(MARK);
 448                 BPF_ANCILLARY(QUEUE);
 449                 BPF_ANCILLARY(HATYPE);
 450                 BPF_ANCILLARY(RXHASH);
 451                 BPF_ANCILLARY(CPU);
 452                 BPF_ANCILLARY(ALU_XOR_X);
 453                 BPF_ANCILLARY(VLAN_TAG);
 454                 BPF_ANCILLARY(VLAN_TAG_PRESENT);
 455                 BPF_ANCILLARY(PAY_OFFSET);
 456                 BPF_ANCILLARY(RANDOM);
 457                 }
 458                 /* Fallthrough. */
 459         default:
 460                 return ftest->code;
 461         }
 462 }
 463
 464 void *bpf_internal_load_pointer_neg_helper(const struct sk_buff *skb,
 465                                            int k, unsigned int size);
 466
 467 static inline void *bpf_load_pointer(const struct sk_buff *skb, int k,
 468                                      unsigned int size, void *buffer)
 469 {
 470         if (k >= 0)
 471                 return skb_header_pointer(skb, k, size, buffer);
 472
 473         return bpf_internal_load_pointer_neg_helper(skb, k, size);
 474 }
 475
 476 static inline int bpf_tell_extensions(void)
 477 {
 478         return SKF_AD_MAX;
 479 }
 480
 481 #endif /* __LINUX_FILTER_H__ */