include/linux/filter.h

   1 /* SPDX-License-Identifier: GPL-2.0 */
   2 /*
   3  * Linux Socket Filter Data Structures
   4  */
   5 #ifndef __LINUX_FILTER_H__
   6 #define __LINUX_FILTER_H__
   7
   8 #include <stdarg.h>
   9
  10 #include <linux/atomic.h>
  11 #include <linux/refcount.h>
  12 #include <linux/compat.h>
  13 #include <linux/skbuff.h>
  14 #include <linux/linkage.h>
  15 #include <linux/printk.h>
  16 #include <linux/workqueue.h>
  17 #include <linux/sched.h>
  18 #include <linux/capability.h>
  19 #include <linux/cryptohash.h>
  20 #include <linux/set_memory.h>
  21 #include <linux/kallsyms.h>
  22
  23 #include <net/sch_generic.h>
  24
  25 #include <uapi/linux/filter.h>
  26 #include <uapi/linux/bpf.h>
  27
  28 struct sk_buff;
  29 struct sock;
  30 struct seccomp_data;
  31 struct bpf_prog_aux;
  32 struct xdp_rxq_info;
  33 struct xdp_buff;
  34
  35 /* ArgX, context and stack frame pointer register positions. Note,
  36  * Arg1, Arg2, Arg3, etc are used as argument mappings of function
  37  * calls in BPF_CALL instruction.
  38  */
  39 #define BPF_REG_ARG1    BPF_REG_1
  40 #define BPF_REG_ARG2    BPF_REG_2
  41 #define BPF_REG_ARG3    BPF_REG_3
  42 #define BPF_REG_ARG4    BPF_REG_4
  43 #define BPF_REG_ARG5    BPF_REG_5
  44 #define BPF_REG_CTX     BPF_REG_6
  45 #define BPF_REG_FP      BPF_REG_10
  46
  47 /* Additional register mappings for converted user programs. */
  48 #define BPF_REG_A       BPF_REG_0
  49 #define BPF_REG_X       BPF_REG_7
  50 #define BPF_REG_TMP     BPF_REG_2       /* scratch reg */
  51 #define BPF_REG_D       BPF_REG_8       /* data, callee-saved */
  52 #define BPF_REG_H       BPF_REG_9       /* hlen, callee-saved */
  53
  54 /* Kernel hidden auxiliary/helper register for hardening step.
  55  * Only used by eBPF JITs. It's nothing more than a temporary
  56  * register that JITs use internally, only that here it's part
  57  * of eBPF instructions that have been rewritten for blinding
  58  * constants. See JIT pre-step in bpf_jit_blind_constants().
  59  */
  60 #define BPF_REG_AX              MAX_BPF_REG
  61 #define MAX_BPF_JIT_REG         (MAX_BPF_REG + 1)
  62
  63 /* unused opcode to mark special call to bpf_tail_call() helper */
  64 #define BPF_TAIL_CALL   0xf0
  65
  66 /* unused opcode to mark call to interpreter with arguments */
  67 #define BPF_CALL_ARGS   0xe0
  68
  69 /* As per nm, we expose JITed images as text (code) section for
  70  * kallsyms. That way, tools like perf can find it to match
  71  * addresses.
  72  */
  73 #define BPF_SYM_ELF_TYPE        't'
  74
  75 /* BPF program can access up to 512 bytes of stack space. */
  76 #define MAX_BPF_STACK   512
  77
  78 /* Helper macros for filter block array initializers. */
  79
  80 /* ALU ops on registers, bpf_add|sub|...: dst_reg += src_reg */
  81
  82 #define BPF_ALU64_REG(OP, DST, SRC)                             \
  83         ((struct bpf_insn) {                                    \
  84                 .code  = BPF_ALU64 | BPF_OP(OP) | BPF_X,        \
  85                 .dst_reg = DST,                                 \
  86                 .src_reg = SRC,                                 \
  87                 .off   = 0,                                     \
  88                 .imm   = 0 })
  89
  90 #define BPF_ALU32_REG(OP, DST, SRC)                             \
  91         ((struct bpf_insn) {                                    \
  92                 .code  = BPF_ALU | BPF_OP(OP) | BPF_X,          \
  93                 .dst_reg = DST,                                 \
  94                 .src_reg = SRC,                                 \
  95                 .off   = 0,                                     \
  96                 .imm   = 0 })
  97
  98 /* ALU ops on immediates, bpf_add|sub|...: dst_reg += imm32 */
  99
 100 #define BPF_ALU64_IMM(OP, DST, IMM)                             \
 101         ((struct bpf_insn) {                                    \
 102                 .code  = BPF_ALU64 | BPF_OP(OP) | BPF_K,        \
 103                 .dst_reg = DST,                                 \
 104                 .src_reg = 0,                                   \
 105                 .off   = 0,                                     \
 106                 .imm   = IMM })
 107
 108 #define BPF_ALU32_IMM(OP, DST, IMM)                             \
 109         ((struct bpf_insn) {                                    \
 110                 .code  = BPF_ALU | BPF_OP(OP) | BPF_K,          \
 111                 .dst_reg = DST,                                 \
 112                 .src_reg = 0,                                   \
 113                 .off   = 0,                                     \
 114                 .imm   = IMM })
 115
 116 /* Endianess conversion, cpu_to_{l,b}e(), {l,b}e_to_cpu() */
 117
 118 #define BPF_ENDIAN(TYPE, DST, LEN)                              \
 119         ((struct bpf_insn) {                                    \
 120                 .code  = BPF_ALU | BPF_END | BPF_SRC(TYPE),     \
 121                 .dst_reg = DST,                                 \
 122                 .src_reg = 0,                                   \
 123                 .off   = 0,                                     \
 124                 .imm   = LEN })
 125
 126 /* Short form of mov, dst_reg = src_reg */
 127
 128 #define BPF_MOV64_REG(DST, SRC)                                 \
 129         ((struct bpf_insn) {                                    \
 130                 .code  = BPF_ALU64 | BPF_MOV | BPF_X,           \
 131                 .dst_reg = DST,                                 \
 132                 .src_reg = SRC,                                 \
 133                 .off   = 0,                                     \
 134                 .imm   = 0 })
 135
 136 #define BPF_MOV32_REG(DST, SRC)                                 \
 137         ((struct bpf_insn) {                                    \
 138                 .code  = BPF_ALU | BPF_MOV | BPF_X,             \
 139                 .dst_reg = DST,                                 \
 140                 .src_reg = SRC,                                 \
 141                 .off   = 0,                                     \
 142                 .imm   = 0 })
 143
 144 /* Short form of mov, dst_reg = imm32 */
 145
 146 #define BPF_MOV64_IMM(DST, IMM)                                 \
 147         ((struct bpf_insn) {                                    \
 148                 .code  = BPF_ALU64 | BPF_MOV | BPF_K,           \
 149                 .dst_reg = DST,                                 \
 150                 .src_reg = 0,                                   \
 151                 .off   = 0,                                     \
 152                 .imm   = IMM })
 153
 154 #define BPF_MOV32_IMM(DST, IMM)                                 \
 155         ((struct bpf_insn) {                                    \
 156                 .code  = BPF_ALU | BPF_MOV | BPF_K,             \
 157                 .dst_reg = DST,                                 \
 158                 .src_reg = 0,                                   \
 159                 .off   = 0,                                     \
 160                 .imm   = IMM })
 161
 162 /* BPF_LD_IMM64 macro encodes single 'load 64-bit immediate' insn */
 163 #define BPF_LD_IMM64(DST, IMM)                                  \
 164         BPF_LD_IMM64_RAW(DST, 0, IMM)
 165
 166 #define BPF_LD_IMM64_RAW(DST, SRC, IMM)                         \
 167         ((struct bpf_insn) {                                    \
 168                 .code  = BPF_LD | BPF_DW | BPF_IMM,             \
 169                 .dst_reg = DST,                                 \
 170                 .src_reg = SRC,                                 \
 171                 .off   = 0,                                     \
 172                 .imm   = (__u32) (IMM) }),                      \
 173         ((struct bpf_insn) {                                    \
 174                 .code  = 0, /* zero is reserved opcode */       \
 175                 .dst_reg = 0,                                   \
 176                 .src_reg = 0,                                   \
 177                 .off   = 0,                                     \
 178                 .imm   = ((__u64) (IMM)) >> 32 })
 179
 180 /* pseudo BPF_LD_IMM64 insn used to refer to process-local map_fd */
 181 #define BPF_LD_MAP_FD(DST, MAP_FD)                              \
 182         BPF_LD_IMM64_RAW(DST, BPF_PSEUDO_MAP_FD, MAP_FD)
 183
 184 /* Short form of mov based on type, BPF_X: dst_reg = src_reg, BPF_K: dst_reg = imm32 */
 185
 186 #define BPF_MOV64_RAW(TYPE, DST, SRC, IMM)                      \
 187         ((struct bpf_insn) {                                    \
 188                 .code  = BPF_ALU64 | BPF_MOV | BPF_SRC(TYPE),   \
 189                 .dst_reg = DST,                                 \
 190                 .src_reg = SRC,                                 \
 191                 .off   = 0,                                     \
 192                 .imm   = IMM })
 193
 194 #define BPF_MOV32_RAW(TYPE, DST, SRC, IMM)                      \
 195         ((struct bpf_insn) {                                    \
 196                 .code  = BPF_ALU | BPF_MOV | BPF_SRC(TYPE),     \
 197                 .dst_reg = DST,                                 \
 198                 .src_reg = SRC,                                 \
 199                 .off   = 0,                                     \
 200                 .imm   = IMM })
 201
 202 /* Direct packet access, R0 = *(uint *) (skb->data + imm32) */
 203
 204 #define BPF_LD_ABS(SIZE, IMM)                                   \
 205         ((struct bpf_insn) {                                    \
 206                 .code  = BPF_LD | BPF_SIZE(SIZE) | BPF_ABS,     \
 207                 .dst_reg = 0,                                   \
 208                 .src_reg = 0,                                   \
 209                 .off   = 0,                                     \
 210                 .imm   = IMM })
 211
 212 /* Indirect packet access, R0 = *(uint *) (skb->data + src_reg + imm32) */
 213
 214 #define BPF_LD_IND(SIZE, SRC, IMM)                              \
 215         ((struct bpf_insn) {                                    \
 216                 .code  = BPF_LD | BPF_SIZE(SIZE) | BPF_IND,     \
 217                 .dst_reg = 0,                                   \
 218                 .src_reg = SRC,                                 \
 219                 .off   = 0,                                     \
 220                 .imm   = IMM })
 221
 222 /* Memory load, dst_reg = *(uint *) (src_reg + off16) */
 223
 224 #define BPF_LDX_MEM(SIZE, DST, SRC, OFF)                        \
 225         ((struct bpf_insn) {                                    \
 226                 .code  = BPF_LDX | BPF_SIZE(SIZE) | BPF_MEM,    \
 227                 .dst_reg = DST,                                 \
 228                 .src_reg = SRC,                                 \
 229                 .off   = OFF,                                   \
 230                 .imm   = 0 })
 231
 232 /* Memory store, *(uint *) (dst_reg + off16) = src_reg */
 233
 234 #define BPF_STX_MEM(SIZE, DST, SRC, OFF)                        \
 235         ((struct bpf_insn) {                                    \
 236                 .code  = BPF_STX | BPF_SIZE(SIZE) | BPF_MEM,    \
 237                 .dst_reg = DST,                                 \
 238                 .src_reg = SRC,                                 \
 239                 .off   = OFF,                                   \
 240                 .imm   = 0 })
 241
 242 /* Atomic memory add, *(uint *)(dst_reg + off16) += src_reg */
 243
 244 #define BPF_STX_XADD(SIZE, DST, SRC, OFF)                       \
 245         ((struct bpf_insn) {                                    \
 246                 .code  = BPF_STX | BPF_SIZE(SIZE) | BPF_XADD,   \
 247                 .dst_reg = DST,                                 \
 248                 .src_reg = SRC,                                 \
 249                 .off   = OFF,                                   \
 250                 .imm   = 0 })
 251
 252 /* Memory store, *(uint *) (dst_reg + off16) = imm32 */
 253
 254 #define BPF_ST_MEM(SIZE, DST, OFF, IMM)                         \
 255         ((struct bpf_insn) {                                    \
 256                 .code  = BPF_ST | BPF_SIZE(SIZE) | BPF_MEM,     \
 257                 .dst_reg = DST,                                 \
 258                 .src_reg = 0,                                   \
 259                 .off   = OFF,                                   \
 260                 .imm   = IMM })
 261
 262 /* Conditional jumps against registers, if (dst_reg 'op' src_reg) goto pc + off16 */
 263
 264 #define BPF_JMP_REG(OP, DST, SRC, OFF)                          \
 265         ((struct bpf_insn) {                                    \
 266                 .code  = BPF_JMP | BPF_OP(OP) | BPF_X,          \
 267                 .dst_reg = DST,                                 \
 268                 .src_reg = SRC,                                 \
 269                 .off   = OFF,                                   \
 270                 .imm   = 0 })
 271
 272 /* Conditional jumps against immediates, if (dst_reg 'op' imm32) goto pc + off16 */
 273
 274 #define BPF_JMP_IMM(OP, DST, IMM, OFF)                          \
 275         ((struct bpf_insn) {                                    \
 276                 .code  = BPF_JMP | BPF_OP(OP) | BPF_K,          \
 277                 .dst_reg = DST,                                 \
 278                 .src_reg = 0,                                   \
 279                 .off   = OFF,                                   \
 280                 .imm   = IMM })
 281
 282 /* Unconditional jumps, goto pc + off16 */
 283
 284 #define BPF_JMP_A(OFF)                                          \
 285         ((struct bpf_insn) {                                    \
 286                 .code  = BPF_JMP | BPF_JA,                      \
 287                 .dst_reg = 0,                                   \
 288                 .src_reg = 0,                                   \
 289                 .off   = OFF,                                   \
 290                 .imm   = 0 })
 291
 292 /* Relative call */
 293
 294 #define BPF_CALL_REL(TGT)                                       \
 295         ((struct bpf_insn) {                                    \
 296                 .code  = BPF_JMP | BPF_CALL,                    \
 297                 .dst_reg = 0,                                   \
 298                 .src_reg = BPF_PSEUDO_CALL,                     \
 299                 .off   = 0,                                     \
 300                 .imm   = TGT })
 301
 302 /* Function call */
 303
 304 #define BPF_CAST_CALL(x)                                        \
 305                 ((u64 (*)(u64, u64, u64, u64, u64))(x))
 306
 307 #define BPF_EMIT_CALL(FUNC)                                     \
 308         ((struct bpf_insn) {                                    \
 309                 .code  = BPF_JMP | BPF_CALL,                    \
 310                 .dst_reg = 0,                                   \
 311                 .src_reg = 0,                                   \
 312                 .off   = 0,                                     \
 313                 .imm   = ((FUNC) - __bpf_call_base) })
 314
 315 /* Raw code statement block */
 316
 317 #define BPF_RAW_INSN(CODE, DST, SRC, OFF, IMM)                  \
 318         ((struct bpf_insn) {                                    \
 319                 .code  = CODE,                                  \
 320                 .dst_reg = DST,                                 \
 321                 .src_reg = SRC,                                 \
 322                 .off   = OFF,                                   \
 323                 .imm   = IMM })
 324
 325 /* Program exit */
 326
 327 #define BPF_EXIT_INSN()                                         \
 328         ((struct bpf_insn) {                                    \
 329                 .code  = BPF_JMP | BPF_EXIT,                    \
 330                 .dst_reg = 0,                                   \
 331                 .src_reg = 0,                                   \
 332                 .off   = 0,                                     \
 333                 .imm   = 0 })
 334
 335 /* Internal classic blocks for direct assignment */
 336
 337 #define __BPF_STMT(CODE, K)                                     \
 338         ((struct sock_filter) BPF_STMT(CODE, K))
 339
 340 #define __BPF_JUMP(CODE, K, JT, JF)                             \
 341         ((struct sock_filter) BPF_JUMP(CODE, K, JT, JF))
 342
 343 #define bytes_to_bpf_size(bytes)                                \
 344 ({                                                              \
 345         int bpf_size = -EINVAL;                                 \
 346                                                                 \
 347         if (bytes == sizeof(u8))                                \
 348                 bpf_size = BPF_B;                               \
 349         else if (bytes == sizeof(u16))                          \
 350                 bpf_size = BPF_H;                               \
 351         else if (bytes == sizeof(u32))                          \
 352                 bpf_size = BPF_W;                               \
 353         else if (bytes == sizeof(u64))                          \
 354                 bpf_size = BPF_DW;                              \
 355                                                                 \
 356         bpf_size;                                               \
 357 })
 358
 359 #define bpf_size_to_bytes(bpf_size)                             \
 360 ({                                                              \
 361         int bytes = -EINVAL;                                    \
 362                                                                 \
 363         if (bpf_size == BPF_B)                                  \
 364                 bytes = sizeof(u8);                             \
 365         else if (bpf_size == BPF_H)                             \
 366                 bytes = sizeof(u16);                            \
 367         else if (bpf_size == BPF_W)                             \
 368                 bytes = sizeof(u32);                            \
 369         else if (bpf_size == BPF_DW)                            \
 370                 bytes = sizeof(u64);                            \
 371                                                                 \
 372         bytes;                                                  \
 373 })
 374
 375 #define BPF_SIZEOF(type)                                        \
 376         ({                                                      \
 377                 const int __size = bytes_to_bpf_size(sizeof(type)); \
 378                 BUILD_BUG_ON(__size < 0);                       \
 379                 __size;                                         \
 380         })
 381
 382 #define BPF_FIELD_SIZEOF(type, field)                           \
 383         ({                                                      \
 384                 const int __size = bytes_to_bpf_size(FIELD_SIZEOF(type, field)); \
 385                 BUILD_BUG_ON(__size < 0);                       \
 386                 __size;                                         \
 387         })
 388
 389 #define BPF_LDST_BYTES(insn)                                    \
 390         ({                                                      \
 391                 const int __size = bpf_size_to_bytes(BPF_SIZE((insn)->code)); \
 392                 WARN_ON(__size < 0);                            \
 393                 __size;                                         \
 394         })
 395
 396 #define __BPF_MAP_0(m, v, ...) v
 397 #define __BPF_MAP_1(m, v, t, a, ...) m(t, a)
 398 #define __BPF_MAP_2(m, v, t, a, ...) m(t, a), __BPF_MAP_1(m, v, __VA_ARGS__)
 399 #define __BPF_MAP_3(m, v, t, a, ...) m(t, a), __BPF_MAP_2(m, v, __VA_ARGS__)
 400 #define __BPF_MAP_4(m, v, t, a, ...) m(t, a), __BPF_MAP_3(m, v, __VA_ARGS__)
 401 #define __BPF_MAP_5(m, v, t, a, ...) m(t, a), __BPF_MAP_4(m, v, __VA_ARGS__)
 402
 403 #define __BPF_REG_0(...) __BPF_PAD(5)
 404 #define __BPF_REG_1(...) __BPF_MAP(1, __VA_ARGS__), __BPF_PAD(4)
 405 #define __BPF_REG_2(...) __BPF_MAP(2, __VA_ARGS__), __BPF_PAD(3)
 406 #define __BPF_REG_3(...) __BPF_MAP(3, __VA_ARGS__), __BPF_PAD(2)
 407 #define __BPF_REG_4(...) __BPF_MAP(4, __VA_ARGS__), __BPF_PAD(1)
 408 #define __BPF_REG_5(...) __BPF_MAP(5, __VA_ARGS__)
 409
 410 #define __BPF_MAP(n, ...) __BPF_MAP_##n(__VA_ARGS__)
 411 #define __BPF_REG(n, ...) __BPF_REG_##n(__VA_ARGS__)
 412
 413 #define __BPF_CAST(t, a)                                                       \
 414         (__force t)                                                            \
 415         (__force                                                               \
 416          typeof(__builtin_choose_expr(sizeof(t) == sizeof(unsigned long),      \
 417                                       (unsigned long)0, (t)0))) a
 418 #define __BPF_V void
 419 #define __BPF_N
 420
 421 #define __BPF_DECL_ARGS(t, a) t   a
 422 #define __BPF_DECL_REGS(t, a) u64 a
 423
 424 #define __BPF_PAD(n)                                                           \
 425         __BPF_MAP(n, __BPF_DECL_ARGS, __BPF_N, u64, __ur_1, u64, __ur_2,       \
 426                   u64, __ur_3, u64, __ur_4, u64, __ur_5)
 427
 428 #define BPF_CALL_x(x, name, ...)                                               \
 429         static __always_inline                                                 \
 430         u64 ____##name(__BPF_MAP(x, __BPF_DECL_ARGS, __BPF_V, __VA_ARGS__));   \
 431         u64 name(__BPF_REG(x, __BPF_DECL_REGS, __BPF_N, __VA_ARGS__));         \
 432         u64 name(__BPF_REG(x, __BPF_DECL_REGS, __BPF_N, __VA_ARGS__))          \
 433         {                                                                      \
 434                 return ____##name(__BPF_MAP(x,__BPF_CAST,__BPF_N,__VA_ARGS__));\
 435         }                                                                      \
 436         static __always_inline                                                 \
 437         u64 ____##name(__BPF_MAP(x, __BPF_DECL_ARGS, __BPF_V, __VA_ARGS__))
 438
 439 #define BPF_CALL_0(name, ...)   BPF_CALL_x(0, name, __VA_ARGS__)
 440 #define BPF_CALL_1(name, ...)   BPF_CALL_x(1, name, __VA_ARGS__)
 441 #define BPF_CALL_2(name, ...)   BPF_CALL_x(2, name, __VA_ARGS__)
 442 #define BPF_CALL_3(name, ...)   BPF_CALL_x(3, name, __VA_ARGS__)
 443 #define BPF_CALL_4(name, ...)   BPF_CALL_x(4, name, __VA_ARGS__)
 444 #define BPF_CALL_5(name, ...)   BPF_CALL_x(5, name, __VA_ARGS__)
 445
 446 #define bpf_ctx_range(TYPE, MEMBER)                                             \
 447         offsetof(TYPE, MEMBER) ... offsetofend(TYPE, MEMBER) - 1
 448 #define bpf_ctx_range_till(TYPE, MEMBER1, MEMBER2)                              \
 449         offsetof(TYPE, MEMBER1) ... offsetofend(TYPE, MEMBER2) - 1
 450
 451 #define bpf_target_off(TYPE, MEMBER, SIZE, PTR_SIZE)                            \
 452         ({                                                                      \
 453                 BUILD_BUG_ON(FIELD_SIZEOF(TYPE, MEMBER) != (SIZE));             \
 454                 *(PTR_SIZE) = (SIZE);                                           \
 455                 offsetof(TYPE, MEMBER);                                         \
 456         })
 457
 458 #ifdef CONFIG_COMPAT
 459 /* A struct sock_filter is architecture independent. */
 460 struct compat_sock_fprog {
 461         u16             len;
 462         compat_uptr_t   filter; /* struct sock_filter * */
 463 };
 464 #endif
 465
 466 struct sock_fprog_kern {
 467         u16                     len;
 468         struct sock_filter      *filter;
 469 };
 470
 471 struct bpf_binary_header {
 472         unsigned int pages;
 473         u8 image[];
 474 };
 475
 476 struct bpf_prog {
 477         u16                     pages;          /* Number of allocated pages */
 478         u16                     jited:1,        /* Is our filter JIT'ed? */
 479                                 jit_requested:1,/* archs need to JIT the prog */
 480                                 locked:1,       /* Program image locked? */
 481                                 gpl_compatible:1, /* Is filter GPL compatible? */
 482                                 cb_access:1,    /* Is control block accessed? */
 483                                 dst_needed:1,   /* Do we need dst entry? */
 484                                 blinded:1,      /* Was blinded */
 485                                 is_func:1,      /* program is a bpf function */
 486                                 kprobe_override:1, /* Do we override a kprobe? */
 487                                 has_callchain_buf:1; /* callchain buffer allocated? */
 488         enum bpf_prog_type      type;           /* Type of BPF program */
 489         enum bpf_attach_type    expected_attach_type; /* For some prog types */
 490         u32                     len;            /* Number of filter blocks */
 491         u32                     jited_len;      /* Size of jited insns in bytes */
 492         u8                      tag[BPF_TAG_SIZE];
 493         struct bpf_prog_aux     *aux;           /* Auxiliary fields */
 494         struct sock_fprog_kern  *orig_prog;     /* Original BPF program */
 495         unsigned int            (*bpf_func)(const void *ctx,
 496                                             const struct bpf_insn *insn);
 497         /* Instructions for interpreter */
 498         union {
 499                 struct sock_filter      insns[0];
 500                 struct bpf_insn         insnsi[0];
 501         };
 502 };
 503
 504 struct sk_filter {
 505         refcount_t      refcnt;
 506         struct rcu_head rcu;
 507         struct bpf_prog *prog;
 508 };
 509
 510 #define BPF_PROG_RUN(filter, ctx)  (*(filter)->bpf_func)(ctx, (filter)->insnsi)
 511
 512 #define BPF_SKB_CB_LEN QDISC_CB_PRIV_LEN
 513
 514 struct bpf_skb_data_end {
 515         struct qdisc_skb_cb qdisc_cb;
 516         void *data_meta;
 517         void *data_end;
 518 };
 519
 520 struct sk_msg_buff {
 521         void *data;
 522         void *data_end;
 523         __u32 apply_bytes;
 524         __u32 cork_bytes;
 525         int sg_copybreak;
 526         int sg_start;
 527         int sg_curr;
 528         int sg_end;
 529         struct scatterlist sg_data[MAX_SKB_FRAGS];
 530         bool sg_copy[MAX_SKB_FRAGS];
 531         __u32 flags;
 532         struct sock *sk_redir;
 533         struct sock *sk;
 534         struct sk_buff *skb;
 535         struct list_head list;
 536 };
 537
 538 /* Compute the linear packet data range [data, data_end) which
 539  * will be accessed by various program types (cls_bpf, act_bpf,
 540  * lwt, ...). Subsystems allowing direct data access must (!)
 541  * ensure that cb[] area can be written to when BPF program is
 542  * invoked (otherwise cb[] save/restore is necessary).
 543  */
 544 static inline void bpf_compute_data_pointers(struct sk_buff *skb)
 545 {
 546         struct bpf_skb_data_end *cb = (struct bpf_skb_data_end *)skb->cb;
 547
 548         BUILD_BUG_ON(sizeof(*cb) > FIELD_SIZEOF(struct sk_buff, cb));
 549         cb->data_meta = skb->data - skb_metadata_len(skb);
 550         cb->data_end  = skb->data + skb_headlen(skb);
 551 }
 552
 553 static inline u8 *bpf_skb_cb(struct sk_buff *skb)
 554 {
 555         /* eBPF programs may read/write skb->cb[] area to transfer meta
 556          * data between tail calls. Since this also needs to work with
 557          * tc, that scratch memory is mapped to qdisc_skb_cb's data area.
 558          *
 559          * In some socket filter cases, the cb unfortunately needs to be
 560          * saved/restored so that protocol specific skb->cb[] data won't
 561          * be lost. In any case, due to unpriviledged eBPF programs
 562          * attached to sockets, we need to clear the bpf_skb_cb() area
 563          * to not leak previous contents to user space.
 564          */
 565         BUILD_BUG_ON(FIELD_SIZEOF(struct __sk_buff, cb) != BPF_SKB_CB_LEN);
 566         BUILD_BUG_ON(FIELD_SIZEOF(struct __sk_buff, cb) !=
 567                      FIELD_SIZEOF(struct qdisc_skb_cb, data));
 568
 569         return qdisc_skb_cb(skb)->data;
 570 }
 571
 572 static inline u32 bpf_prog_run_save_cb(const struct bpf_prog *prog,
 573                                        struct sk_buff *skb)
 574 {
 575         u8 *cb_data = bpf_skb_cb(skb);
 576         u8 cb_saved[BPF_SKB_CB_LEN];
 577         u32 res;
 578
 579         if (unlikely(prog->cb_access)) {
 580                 memcpy(cb_saved, cb_data, sizeof(cb_saved));
 581                 memset(cb_data, 0, sizeof(cb_saved));
 582         }
 583
 584         res = BPF_PROG_RUN(prog, skb);
 585
 586         if (unlikely(prog->cb_access))
 587                 memcpy(cb_data, cb_saved, sizeof(cb_saved));
 588
 589         return res;
 590 }
 591
 592 static inline u32 bpf_prog_run_clear_cb(const struct bpf_prog *prog,
 593                                         struct sk_buff *skb)
 594 {
 595         u8 *cb_data = bpf_skb_cb(skb);
 596
 597         if (unlikely(prog->cb_access))
 598                 memset(cb_data, 0, BPF_SKB_CB_LEN);
 599
 600         return BPF_PROG_RUN(prog, skb);
 601 }
 602
 603 static __always_inline u32 bpf_prog_run_xdp(const struct bpf_prog *prog,
 604                                             struct xdp_buff *xdp)
 605 {
 606         /* Caller needs to hold rcu_read_lock() (!), otherwise program
 607          * can be released while still running, or map elements could be
 608          * freed early while still having concurrent users. XDP fastpath
 609          * already takes rcu_read_lock() when fetching the program, so
 610          * it's not necessary here anymore.
 611          */
 612         return BPF_PROG_RUN(prog, xdp);
 613 }
 614
 615 static inline u32 bpf_prog_insn_size(const struct bpf_prog *prog)
 616 {
 617         return prog->len * sizeof(struct bpf_insn);
 618 }
 619
 620 static inline u32 bpf_prog_tag_scratch_size(const struct bpf_prog *prog)
 621 {
 622         return round_up(bpf_prog_insn_size(prog) +
 623                         sizeof(__be64) + 1, SHA_MESSAGE_BYTES);
 624 }
 625
 626 static inline unsigned int bpf_prog_size(unsigned int proglen)
 627 {
 628         return max(sizeof(struct bpf_prog),
 629                    offsetof(struct bpf_prog, insns[proglen]));
 630 }
 631
 632 static inline bool bpf_prog_was_classic(const struct bpf_prog *prog)
 633 {
 634         /* When classic BPF programs have been loaded and the arch
 635          * does not have a classic BPF JIT (anymore), they have been
 636          * converted via bpf_migrate_filter() to eBPF and thus always
 637          * have an unspec program type.
 638          */
 639         return prog->type == BPF_PROG_TYPE_UNSPEC;
 640 }
 641
 642 static inline u32 bpf_ctx_off_adjust_machine(u32 size)
 643 {
 644         const u32 size_machine = sizeof(unsigned long);
 645
 646         if (size > size_machine && size % size_machine == 0)
 647                 size = size_machine;
 648
 649         return size;
 650 }
 651
 652 static inline bool bpf_ctx_narrow_align_ok(u32 off, u32 size_access,
 653                                            u32 size_default)
 654 {
 655         size_default = bpf_ctx_off_adjust_machine(size_default);
 656         size_access  = bpf_ctx_off_adjust_machine(size_access);
 657
 658 #ifdef __LITTLE_ENDIAN
 659         return (off & (size_default - 1)) == 0;
 660 #else
 661         return (off & (size_default - 1)) + size_access == size_default;
 662 #endif
 663 }
 664
 665 static inline bool
 666 bpf_ctx_narrow_access_ok(u32 off, u32 size, u32 size_default)
 667 {
 668         return bpf_ctx_narrow_align_ok(off, size, size_default) &&
 669                size <= size_default && (size & (size - 1)) == 0;
 670 }
 671
 672 #define bpf_classic_proglen(fprog) (fprog->len * sizeof(fprog->filter[0]))
 673
 674 #ifdef CONFIG_ARCH_HAS_SET_MEMORY
 675 static inline void bpf_prog_lock_ro(struct bpf_prog *fp)
 676 {
 677         fp->locked = 1;
 678         WARN_ON_ONCE(set_memory_ro((unsigned long)fp, fp->pages));
 679 }
 680
 681 static inline void bpf_prog_unlock_ro(struct bpf_prog *fp)
 682 {
 683         if (fp->locked) {
 684                 WARN_ON_ONCE(set_memory_rw((unsigned long)fp, fp->pages));
 685                 /* In case set_memory_rw() fails, we want to be the first
 686                  * to crash here instead of some random place later on.
 687                  */
 688                 fp->locked = 0;
 689         }
 690 }
 691
 692 static inline void bpf_jit_binary_lock_ro(struct bpf_binary_header *hdr)
 693 {
 694         WARN_ON_ONCE(set_memory_ro((unsigned long)hdr, hdr->pages));
 695 }
 696
 697 static inline void bpf_jit_binary_unlock_ro(struct bpf_binary_header *hdr)
 698 {
 699         WARN_ON_ONCE(set_memory_rw((unsigned long)hdr, hdr->pages));
 700 }
 701 #else
 702 static inline void bpf_prog_lock_ro(struct bpf_prog *fp)
 703 {
 704 }
 705
 706 static inline void bpf_prog_unlock_ro(struct bpf_prog *fp)
 707 {
 708 }
 709
 710 static inline void bpf_jit_binary_lock_ro(struct bpf_binary_header *hdr)
 711 {
 712 }
 713
 714 static inline void bpf_jit_binary_unlock_ro(struct bpf_binary_header *hdr)
 715 {
 716 }
 717 #endif /* CONFIG_ARCH_HAS_SET_MEMORY */
 718
 719 static inline struct bpf_binary_header *
 720 bpf_jit_binary_hdr(const struct bpf_prog *fp)
 721 {
 722         unsigned long real_start = (unsigned long)fp->bpf_func;
 723         unsigned long addr = real_start & PAGE_MASK;
 724
 725         return (void *)addr;
 726 }
 727
 728 int sk_filter_trim_cap(struct sock *sk, struct sk_buff *skb, unsigned int cap);
 729 static inline int sk_filter(struct sock *sk, struct sk_buff *skb)
 730 {
 731         return sk_filter_trim_cap(sk, skb, 1);
 732 }
 733
 734 struct bpf_prog *bpf_prog_select_runtime(struct bpf_prog *fp, int *err);
 735 void bpf_prog_free(struct bpf_prog *fp);
 736
 737 bool bpf_opcode_in_insntable(u8 code);
 738
 739 struct bpf_prog *bpf_prog_alloc(unsigned int size, gfp_t gfp_extra_flags);
 740 struct bpf_prog *bpf_prog_realloc(struct bpf_prog *fp_old, unsigned int size,
 741                                   gfp_t gfp_extra_flags);
 742 void __bpf_prog_free(struct bpf_prog *fp);
 743
 744 static inline void bpf_prog_unlock_free(struct bpf_prog *fp)
 745 {
 746         bpf_prog_unlock_ro(fp);
 747         __bpf_prog_free(fp);
 748 }
 749
 750 typedef int (*bpf_aux_classic_check_t)(struct sock_filter *filter,
 751                                        unsigned int flen);
 752
 753 int bpf_prog_create(struct bpf_prog **pfp, struct sock_fprog_kern *fprog);
 754 int bpf_prog_create_from_user(struct bpf_prog **pfp, struct sock_fprog *fprog,
 755                               bpf_aux_classic_check_t trans, bool save_orig);
 756 void bpf_prog_destroy(struct bpf_prog *fp);
 757
 758 int sk_attach_filter(struct sock_fprog *fprog, struct sock *sk);
 759 int sk_attach_bpf(u32 ufd, struct sock *sk);
 760 int sk_reuseport_attach_filter(struct sock_fprog *fprog, struct sock *sk);
 761 int sk_reuseport_attach_bpf(u32 ufd, struct sock *sk);
 762 int sk_detach_filter(struct sock *sk);
 763 int sk_get_filter(struct sock *sk, struct sock_filter __user *filter,
 764                   unsigned int len);
 765
 766 bool sk_filter_charge(struct sock *sk, struct sk_filter *fp);
 767 void sk_filter_uncharge(struct sock *sk, struct sk_filter *fp);
 768
 769 u64 __bpf_call_base(u64 r1, u64 r2, u64 r3, u64 r4, u64 r5);
 770 #define __bpf_call_base_args \
 771         ((u64 (*)(u64, u64, u64, u64, u64, const struct bpf_insn *)) \
 772          __bpf_call_base)
 773
 774 struct bpf_prog *bpf_int_jit_compile(struct bpf_prog *prog);
 775 void bpf_jit_compile(struct bpf_prog *prog);
 776 bool bpf_helper_changes_pkt_data(void *func);
 777
 778 static inline bool bpf_dump_raw_ok(void)
 779 {
 780         /* Reconstruction of call-sites is dependent on kallsyms,
 781          * thus make dump the same restriction.
 782          */
 783         return kallsyms_show_value() == 1;
 784 }
 785
 786 struct bpf_prog *bpf_patch_insn_single(struct bpf_prog *prog, u32 off,
 787                                        const struct bpf_insn *patch, u32 len);
 788
 789 /* The pair of xdp_do_redirect and xdp_do_flush_map MUST be called in the
 790  * same cpu context. Further for best results no more than a single map
 791  * for the do_redirect/do_flush pair should be used. This limitation is
 792  * because we only track one map and force a flush when the map changes.
 793  * This does not appear to be a real limitation for existing software.
 794  */
 795 int xdp_do_generic_redirect(struct net_device *dev, struct sk_buff *skb,
 796                             struct xdp_buff *xdp, struct bpf_prog *prog);
 797 int xdp_do_redirect(struct net_device *dev,
 798                     struct xdp_buff *xdp,
 799                     struct bpf_prog *prog);
 800 void xdp_do_flush_map(void);
 801
 802 void bpf_warn_invalid_xdp_action(u32 act);
 803
 804 struct sock *do_sk_redirect_map(struct sk_buff *skb);
 805 struct sock *do_msg_redirect_map(struct sk_msg_buff *md);
 806
 807 #ifdef CONFIG_BPF_JIT
 808 extern int bpf_jit_enable;
 809 extern int bpf_jit_harden;
 810 extern int bpf_jit_kallsyms;
 811
 812 typedef void (*bpf_jit_fill_hole_t)(void *area, unsigned int size);
 813
 814 struct bpf_binary_header *
 815 bpf_jit_binary_alloc(unsigned int proglen, u8 **image_ptr,
 816                      unsigned int alignment,
 817                      bpf_jit_fill_hole_t bpf_fill_ill_insns);
 818 void bpf_jit_binary_free(struct bpf_binary_header *hdr);
 819
 820 void bpf_jit_free(struct bpf_prog *fp);
 821
 822 struct bpf_prog *bpf_jit_blind_constants(struct bpf_prog *fp);
 823 void bpf_jit_prog_release_other(struct bpf_prog *fp, struct bpf_prog *fp_other);
 824
 825 static inline void bpf_jit_dump(unsigned int flen, unsigned int proglen,
 826                                 u32 pass, void *image)
 827 {
 828         pr_err("flen=%u proglen=%u pass=%u image=%pK from=%s pid=%d\n", flen,
 829                proglen, pass, image, current->comm, task_pid_nr(current));
 830
 831         if (image)
 832                 print_hex_dump(KERN_ERR, "JIT code: ", DUMP_PREFIX_OFFSET,
 833                                16, 1, image, proglen, false);
 834 }
 835
 836 static inline bool bpf_jit_is_ebpf(void)
 837 {
 838 # ifdef CONFIG_HAVE_EBPF_JIT
 839         return true;
 840 # else
 841         return false;
 842 # endif
 843 }
 844
 845 static inline bool ebpf_jit_enabled(void)
 846 {
 847         return bpf_jit_enable && bpf_jit_is_ebpf();
 848 }
 849
 850 static inline bool bpf_prog_ebpf_jited(const struct bpf_prog *fp)
 851 {
 852         return fp->jited && bpf_jit_is_ebpf();
 853 }
 854
 855 static inline bool bpf_jit_blinding_enabled(struct bpf_prog *prog)
 856 {
 857         /* These are the prerequisites, should someone ever have the
 858          * idea to call blinding outside of them, we make sure to
 859          * bail out.
 860          */
 861         if (!bpf_jit_is_ebpf())
 862                 return false;
 863         if (!prog->jit_requested)
 864                 return false;
 865         if (!bpf_jit_harden)
 866                 return false;
 867         if (bpf_jit_harden == 1 && capable(CAP_SYS_ADMIN))
 868                 return false;
 869
 870         return true;
 871 }
 872
 873 static inline bool bpf_jit_kallsyms_enabled(void)
 874 {
 875         /* There are a couple of corner cases where kallsyms should
 876          * not be enabled f.e. on hardening.
 877          */
 878         if (bpf_jit_harden)
 879                 return false;
 880         if (!bpf_jit_kallsyms)
 881                 return false;
 882         if (bpf_jit_kallsyms == 1)
 883                 return true;
 884
 885         return false;
 886 }
 887
 888 const char *__bpf_address_lookup(unsigned long addr, unsigned long *size,
 889                                  unsigned long *off, char *sym);
 890 bool is_bpf_text_address(unsigned long addr);
 891 int bpf_get_kallsym(unsigned int symnum, unsigned long *value, char *type,
 892                     char *sym);
 893
 894 static inline const char *
 895 bpf_address_lookup(unsigned long addr, unsigned long *size,
 896                    unsigned long *off, char **modname, char *sym)
 897 {
 898         const char *ret = __bpf_address_lookup(addr, size, off, sym);
 899
 900         if (ret && modname)
 901                 *modname = NULL;
 902         return ret;
 903 }
 904
 905 void bpf_prog_kallsyms_add(struct bpf_prog *fp);
 906 void bpf_prog_kallsyms_del(struct bpf_prog *fp);
 907
 908 #else /* CONFIG_BPF_JIT */
 909
 910 static inline bool ebpf_jit_enabled(void)
 911 {
 912         return false;
 913 }
 914
 915 static inline bool bpf_prog_ebpf_jited(const struct bpf_prog *fp)
 916 {
 917         return false;
 918 }
 919
 920 static inline void bpf_jit_free(struct bpf_prog *fp)
 921 {
 922         bpf_prog_unlock_free(fp);
 923 }
 924
 925 static inline bool bpf_jit_kallsyms_enabled(void)
 926 {
 927         return false;
 928 }
 929
 930 static inline const char *
 931 __bpf_address_lookup(unsigned long addr, unsigned long *size,
 932                      unsigned long *off, char *sym)
 933 {
 934         return NULL;
 935 }
 936
 937 static inline bool is_bpf_text_address(unsigned long addr)
 938 {
 939         return false;
 940 }
 941
 942 static inline int bpf_get_kallsym(unsigned int symnum, unsigned long *value,
 943                                   char *type, char *sym)
 944 {
 945         return -ERANGE;
 946 }
 947
 948 static inline const char *
 949 bpf_address_lookup(unsigned long addr, unsigned long *size,
 950                    unsigned long *off, char **modname, char *sym)
 951 {
 952         return NULL;
 953 }
 954
 955 static inline void bpf_prog_kallsyms_add(struct bpf_prog *fp)
 956 {
 957 }
 958
 959 static inline void bpf_prog_kallsyms_del(struct bpf_prog *fp)
 960 {
 961 }
 962 #endif /* CONFIG_BPF_JIT */
 963
 964 #define BPF_ANC         BIT(15)
 965
 966 static inline bool bpf_needs_clear_a(const struct sock_filter *first)
 967 {
 968         switch (first->code) {
 969         case BPF_RET | BPF_K:
 970         case BPF_LD | BPF_W | BPF_LEN:
 971                 return false;
 972
 973         case BPF_LD | BPF_W | BPF_ABS:
 974         case BPF_LD | BPF_H | BPF_ABS:
 975         case BPF_LD | BPF_B | BPF_ABS:
 976                 if (first->k == SKF_AD_OFF + SKF_AD_ALU_XOR_X)
 977                         return true;
 978                 return false;
 979
 980         default:
 981                 return true;
 982         }
 983 }
 984
 985 static inline u16 bpf_anc_helper(const struct sock_filter *ftest)
 986 {
 987         BUG_ON(ftest->code & BPF_ANC);
 988
 989         switch (ftest->code) {
 990         case BPF_LD | BPF_W | BPF_ABS:
 991         case BPF_LD | BPF_H | BPF_ABS:
 992         case BPF_LD | BPF_B | BPF_ABS:
 993 #define BPF_ANCILLARY(CODE)     case SKF_AD_OFF + SKF_AD_##CODE:        \
 994                                 return BPF_ANC | SKF_AD_##CODE
 995                 switch (ftest->k) {
 996                 BPF_ANCILLARY(PROTOCOL);
 997                 BPF_ANCILLARY(PKTTYPE);
 998                 BPF_ANCILLARY(IFINDEX);
 999                 BPF_ANCILLARY(NLATTR);
1000                 BPF_ANCILLARY(NLATTR_NEST);
1001                 BPF_ANCILLARY(MARK);
1002                 BPF_ANCILLARY(QUEUE);
1003                 BPF_ANCILLARY(HATYPE);
1004                 BPF_ANCILLARY(RXHASH);
1005                 BPF_ANCILLARY(CPU);
1006                 BPF_ANCILLARY(ALU_XOR_X);
1007                 BPF_ANCILLARY(VLAN_TAG);
1008                 BPF_ANCILLARY(VLAN_TAG_PRESENT);
1009                 BPF_ANCILLARY(PAY_OFFSET);
1010                 BPF_ANCILLARY(RANDOM);
1011                 BPF_ANCILLARY(VLAN_TPID);
1012                 }
1013                 /* Fallthrough. */
1014         default:
1015                 return ftest->code;
1016         }
1017 }
1018
1019 void *bpf_internal_load_pointer_neg_helper(const struct sk_buff *skb,
1020                                            int k, unsigned int size);
1021
1022 static inline void *bpf_load_pointer(const struct sk_buff *skb, int k,
1023                                      unsigned int size, void *buffer)
1024 {
1025         if (k >= 0)
1026                 return skb_header_pointer(skb, k, size, buffer);
1027
1028         return bpf_internal_load_pointer_neg_helper(skb, k, size);
1029 }
1030
1031 static inline int bpf_tell_extensions(void)
1032 {
1033         return SKF_AD_MAX;
1034 }
1035
1036 struct bpf_sock_addr_kern {
1037         struct sock *sk;
1038         struct sockaddr *uaddr;
1039         /* Temporary "register" to make indirect stores to nested structures
1040          * defined above. We need three registers to make such a store, but
1041          * only two (src and dst) are available at convert_ctx_access time
1042          */
1043         u64 tmp_reg;
1044         void *t_ctx;    /* Attach type specific context. */
1045 };
1046
1047 struct bpf_sock_ops_kern {
1048         struct  sock *sk;
1049         u32     op;
1050         union {
1051                 u32 args[4];
1052                 u32 reply;
1053                 u32 replylong[4];
1054         };
1055         u32     is_fullsock;
1056         u64     temp;                   /* temp and everything after is not
1057                                          * initialized to 0 before calling
1058                                          * the BPF program. New fields that
1059                                          * should be initialized to 0 should
1060                                          * be inserted before temp.
1061                                          * temp is scratch storage used by
1062                                          * sock_ops_convert_ctx_access
1063                                          * as temporary storage of a register.
1064                                          */
1065 };
1066
1067 #endif /* __LINUX_FILTER_H__ */