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 #include <linux/sched.h> 16 17 #include <asm/cacheflush.h> 18 19 #include <uapi/linux/filter.h> 20 #include <uapi/linux/bpf.h> 21 22 struct sk_buff; 23 struct sock; 24 struct seccomp_data; 25 struct bpf_prog_aux; 26 27 /* ArgX, context and stack frame pointer register positions. Note, 28 * Arg1, Arg2, Arg3, etc are used as argument mappings of function 29 * calls in BPF_CALL instruction. 30 */ 31 #define BPF_REG_ARG1 BPF_REG_1 32 #define BPF_REG_ARG2 BPF_REG_2 33 #define BPF_REG_ARG3 BPF_REG_3 34 #define BPF_REG_ARG4 BPF_REG_4 35 #define BPF_REG_ARG5 BPF_REG_5 36 #define BPF_REG_CTX BPF_REG_6 37 #define BPF_REG_FP BPF_REG_10 38 39 /* Additional register mappings for converted user programs. */ 40 #define BPF_REG_A BPF_REG_0 41 #define BPF_REG_X BPF_REG_7 42 #define BPF_REG_TMP BPF_REG_8 43 44 /* BPF program can access up to 512 bytes of stack space. */ 45 #define MAX_BPF_STACK 512 46 47 /* Helper macros for filter block array initializers. */ 48 49 /* ALU ops on registers, bpf_add|sub|...: dst_reg += src_reg */ 50 51 #define BPF_ALU64_REG(OP, DST, SRC) \ 52 ((struct bpf_insn) { \ 53 .code = BPF_ALU64 | BPF_OP(OP) | BPF_X, \ 54 .dst_reg = DST, \ 55 .src_reg = SRC, \ 56 .off = 0, \ 57 .imm = 0 }) 58 59 #define BPF_ALU32_REG(OP, DST, SRC) \ 60 ((struct bpf_insn) { \ 61 .code = BPF_ALU | BPF_OP(OP) | BPF_X, \ 62 .dst_reg = DST, \ 63 .src_reg = SRC, \ 64 .off = 0, \ 65 .imm = 0 }) 66 67 /* ALU ops on immediates, bpf_add|sub|...: dst_reg += imm32 */ 68 69 #define BPF_ALU64_IMM(OP, DST, IMM) \ 70 ((struct bpf_insn) { \ 71 .code = BPF_ALU64 | BPF_OP(OP) | BPF_K, \ 72 .dst_reg = DST, \ 73 .src_reg = 0, \ 74 .off = 0, \ 75 .imm = IMM }) 76 77 #define BPF_ALU32_IMM(OP, DST, IMM) \ 78 ((struct bpf_insn) { \ 79 .code = BPF_ALU | BPF_OP(OP) | BPF_K, \ 80 .dst_reg = DST, \ 81 .src_reg = 0, \ 82 .off = 0, \ 83 .imm = IMM }) 84 85 /* Endianess conversion, cpu_to_{l,b}e(), {l,b}e_to_cpu() */ 86 87 #define BPF_ENDIAN(TYPE, DST, LEN) \ 88 ((struct bpf_insn) { \ 89 .code = BPF_ALU | BPF_END | BPF_SRC(TYPE), \ 90 .dst_reg = DST, \ 91 .src_reg = 0, \ 92 .off = 0, \ 93 .imm = LEN }) 94 95 /* Short form of mov, dst_reg = src_reg */ 96 97 #define BPF_MOV64_REG(DST, SRC) \ 98 ((struct bpf_insn) { \ 99 .code = BPF_ALU64 | BPF_MOV | BPF_X, \ 100 .dst_reg = DST, \ 101 .src_reg = SRC, \ 102 .off = 0, \ 103 .imm = 0 }) 104 105 #define BPF_MOV32_REG(DST, SRC) \ 106 ((struct bpf_insn) { \ 107 .code = BPF_ALU | BPF_MOV | BPF_X, \ 108 .dst_reg = DST, \ 109 .src_reg = SRC, \ 110 .off = 0, \ 111 .imm = 0 }) 112 113 /* Short form of mov, dst_reg = imm32 */ 114 115 #define BPF_MOV64_IMM(DST, IMM) \ 116 ((struct bpf_insn) { \ 117 .code = BPF_ALU64 | BPF_MOV | BPF_K, \ 118 .dst_reg = DST, \ 119 .src_reg = 0, \ 120 .off = 0, \ 121 .imm = IMM }) 122 123 #define BPF_MOV32_IMM(DST, IMM) \ 124 ((struct bpf_insn) { \ 125 .code = BPF_ALU | BPF_MOV | BPF_K, \ 126 .dst_reg = DST, \ 127 .src_reg = 0, \ 128 .off = 0, \ 129 .imm = IMM }) 130 131 /* BPF_LD_IMM64 macro encodes single 'load 64-bit immediate' insn */ 132 #define BPF_LD_IMM64(DST, IMM) \ 133 BPF_LD_IMM64_RAW(DST, 0, IMM) 134 135 #define BPF_LD_IMM64_RAW(DST, SRC, IMM) \ 136 ((struct bpf_insn) { \ 137 .code = BPF_LD | BPF_DW | BPF_IMM, \ 138 .dst_reg = DST, \ 139 .src_reg = SRC, \ 140 .off = 0, \ 141 .imm = (__u32) (IMM) }), \ 142 ((struct bpf_insn) { \ 143 .code = 0, /* zero is reserved opcode */ \ 144 .dst_reg = 0, \ 145 .src_reg = 0, \ 146 .off = 0, \ 147 .imm = ((__u64) (IMM)) >> 32 }) 148 149 /* pseudo BPF_LD_IMM64 insn used to refer to process-local map_fd */ 150 #define BPF_LD_MAP_FD(DST, MAP_FD) \ 151 BPF_LD_IMM64_RAW(DST, BPF_PSEUDO_MAP_FD, MAP_FD) 152 153 /* Short form of mov based on type, BPF_X: dst_reg = src_reg, BPF_K: dst_reg = imm32 */ 154 155 #define BPF_MOV64_RAW(TYPE, DST, SRC, IMM) \ 156 ((struct bpf_insn) { \ 157 .code = BPF_ALU64 | BPF_MOV | BPF_SRC(TYPE), \ 158 .dst_reg = DST, \ 159 .src_reg = SRC, \ 160 .off = 0, \ 161 .imm = IMM }) 162 163 #define BPF_MOV32_RAW(TYPE, DST, SRC, IMM) \ 164 ((struct bpf_insn) { \ 165 .code = BPF_ALU | BPF_MOV | BPF_SRC(TYPE), \ 166 .dst_reg = DST, \ 167 .src_reg = SRC, \ 168 .off = 0, \ 169 .imm = IMM }) 170 171 /* Direct packet access, R0 = *(uint *) (skb->data + imm32) */ 172 173 #define BPF_LD_ABS(SIZE, IMM) \ 174 ((struct bpf_insn) { \ 175 .code = BPF_LD | BPF_SIZE(SIZE) | BPF_ABS, \ 176 .dst_reg = 0, \ 177 .src_reg = 0, \ 178 .off = 0, \ 179 .imm = IMM }) 180 181 /* Indirect packet access, R0 = *(uint *) (skb->data + src_reg + imm32) */ 182 183 #define BPF_LD_IND(SIZE, SRC, IMM) \ 184 ((struct bpf_insn) { \ 185 .code = BPF_LD | BPF_SIZE(SIZE) | BPF_IND, \ 186 .dst_reg = 0, \ 187 .src_reg = SRC, \ 188 .off = 0, \ 189 .imm = IMM }) 190 191 /* Memory load, dst_reg = *(uint *) (src_reg + off16) */ 192 193 #define BPF_LDX_MEM(SIZE, DST, SRC, OFF) \ 194 ((struct bpf_insn) { \ 195 .code = BPF_LDX | BPF_SIZE(SIZE) | BPF_MEM, \ 196 .dst_reg = DST, \ 197 .src_reg = SRC, \ 198 .off = OFF, \ 199 .imm = 0 }) 200 201 /* Memory store, *(uint *) (dst_reg + off16) = src_reg */ 202 203 #define BPF_STX_MEM(SIZE, DST, SRC, OFF) \ 204 ((struct bpf_insn) { \ 205 .code = BPF_STX | BPF_SIZE(SIZE) | BPF_MEM, \ 206 .dst_reg = DST, \ 207 .src_reg = SRC, \ 208 .off = OFF, \ 209 .imm = 0 }) 210 211 /* Atomic memory add, *(uint *)(dst_reg + off16) += src_reg */ 212 213 #define BPF_STX_XADD(SIZE, DST, SRC, OFF) \ 214 ((struct bpf_insn) { \ 215 .code = BPF_STX | BPF_SIZE(SIZE) | BPF_XADD, \ 216 .dst_reg = DST, \ 217 .src_reg = SRC, \ 218 .off = OFF, \ 219 .imm = 0 }) 220 221 /* Memory store, *(uint *) (dst_reg + off16) = imm32 */ 222 223 #define BPF_ST_MEM(SIZE, DST, OFF, IMM) \ 224 ((struct bpf_insn) { \ 225 .code = BPF_ST | BPF_SIZE(SIZE) | BPF_MEM, \ 226 .dst_reg = DST, \ 227 .src_reg = 0, \ 228 .off = OFF, \ 229 .imm = IMM }) 230 231 /* Conditional jumps against registers, if (dst_reg 'op' src_reg) goto pc + off16 */ 232 233 #define BPF_JMP_REG(OP, DST, SRC, OFF) \ 234 ((struct bpf_insn) { \ 235 .code = BPF_JMP | BPF_OP(OP) | BPF_X, \ 236 .dst_reg = DST, \ 237 .src_reg = SRC, \ 238 .off = OFF, \ 239 .imm = 0 }) 240 241 /* Conditional jumps against immediates, if (dst_reg 'op' imm32) goto pc + off16 */ 242 243 #define BPF_JMP_IMM(OP, DST, IMM, OFF) \ 244 ((struct bpf_insn) { \ 245 .code = BPF_JMP | BPF_OP(OP) | BPF_K, \ 246 .dst_reg = DST, \ 247 .src_reg = 0, \ 248 .off = OFF, \ 249 .imm = IMM }) 250 251 /* Function call */ 252 253 #define BPF_EMIT_CALL(FUNC) \ 254 ((struct bpf_insn) { \ 255 .code = BPF_JMP | BPF_CALL, \ 256 .dst_reg = 0, \ 257 .src_reg = 0, \ 258 .off = 0, \ 259 .imm = ((FUNC) - __bpf_call_base) }) 260 261 /* Raw code statement block */ 262 263 #define BPF_RAW_INSN(CODE, DST, SRC, OFF, IMM) \ 264 ((struct bpf_insn) { \ 265 .code = CODE, \ 266 .dst_reg = DST, \ 267 .src_reg = SRC, \ 268 .off = OFF, \ 269 .imm = IMM }) 270 271 /* Program exit */ 272 273 #define BPF_EXIT_INSN() \ 274 ((struct bpf_insn) { \ 275 .code = BPF_JMP | BPF_EXIT, \ 276 .dst_reg = 0, \ 277 .src_reg = 0, \ 278 .off = 0, \ 279 .imm = 0 }) 280 281 /* Internal classic blocks for direct assignment */ 282 283 #define __BPF_STMT(CODE, K) \ 284 ((struct sock_filter) BPF_STMT(CODE, K)) 285 286 #define __BPF_JUMP(CODE, K, JT, JF) \ 287 ((struct sock_filter) BPF_JUMP(CODE, K, JT, JF)) 288 289 #define bytes_to_bpf_size(bytes) \ 290 ({ \ 291 int bpf_size = -EINVAL; \ 292 \ 293 if (bytes == sizeof(u8)) \ 294 bpf_size = BPF_B; \ 295 else if (bytes == sizeof(u16)) \ 296 bpf_size = BPF_H; \ 297 else if (bytes == sizeof(u32)) \ 298 bpf_size = BPF_W; \ 299 else if (bytes == sizeof(u64)) \ 300 bpf_size = BPF_DW; \ 301 \ 302 bpf_size; \ 303 }) 304 305 /* Macro to invoke filter function. */ 306 #define SK_RUN_FILTER(filter, ctx) \ 307 (*filter->prog->bpf_func)(ctx, filter->prog->insnsi) 308 309 #ifdef CONFIG_COMPAT 310 /* A struct sock_filter is architecture independent. */ 311 struct compat_sock_fprog { 312 u16 len; 313 compat_uptr_t filter; /* struct sock_filter * */ 314 }; 315 #endif 316 317 struct sock_fprog_kern { 318 u16 len; 319 struct sock_filter *filter; 320 }; 321 322 struct bpf_binary_header { 323 unsigned int pages; 324 u8 image[]; 325 }; 326 327 struct bpf_prog { 328 u16 pages; /* Number of allocated pages */ 329 bool jited; /* Is our filter JIT'ed? */ 330 bool gpl_compatible; /* Is our filter GPL compatible? */ 331 u32 len; /* Number of filter blocks */ 332 enum bpf_prog_type type; /* Type of BPF program */ 333 struct bpf_prog_aux *aux; /* Auxiliary fields */ 334 struct sock_fprog_kern *orig_prog; /* Original BPF program */ 335 unsigned int (*bpf_func)(const struct sk_buff *skb, 336 const struct bpf_insn *filter); 337 /* Instructions for interpreter */ 338 union { 339 struct sock_filter insns[0]; 340 struct bpf_insn insnsi[0]; 341 }; 342 }; 343 344 struct sk_filter { 345 atomic_t refcnt; 346 struct rcu_head rcu; 347 struct bpf_prog *prog; 348 }; 349 350 #define BPF_PROG_RUN(filter, ctx) (*filter->bpf_func)(ctx, filter->insnsi) 351 352 static inline unsigned int bpf_prog_size(unsigned int proglen) 353 { 354 return max(sizeof(struct bpf_prog), 355 offsetof(struct bpf_prog, insns[proglen])); 356 } 357 358 static inline bool bpf_prog_was_classic(const struct bpf_prog *prog) 359 { 360 /* When classic BPF programs have been loaded and the arch 361 * does not have a classic BPF JIT (anymore), they have been 362 * converted via bpf_migrate_filter() to eBPF and thus always 363 * have an unspec program type. 364 */ 365 return prog->type == BPF_PROG_TYPE_UNSPEC; 366 } 367 368 #define bpf_classic_proglen(fprog) (fprog->len * sizeof(fprog->filter[0])) 369 370 #ifdef CONFIG_DEBUG_SET_MODULE_RONX 371 static inline void bpf_prog_lock_ro(struct bpf_prog *fp) 372 { 373 set_memory_ro((unsigned long)fp, fp->pages); 374 } 375 376 static inline void bpf_prog_unlock_ro(struct bpf_prog *fp) 377 { 378 set_memory_rw((unsigned long)fp, fp->pages); 379 } 380 #else 381 static inline void bpf_prog_lock_ro(struct bpf_prog *fp) 382 { 383 } 384 385 static inline void bpf_prog_unlock_ro(struct bpf_prog *fp) 386 { 387 } 388 #endif /* CONFIG_DEBUG_SET_MODULE_RONX */ 389 390 int sk_filter(struct sock *sk, struct sk_buff *skb); 391 392 int bpf_prog_select_runtime(struct bpf_prog *fp); 393 void bpf_prog_free(struct bpf_prog *fp); 394 395 struct bpf_prog *bpf_prog_alloc(unsigned int size, gfp_t gfp_extra_flags); 396 struct bpf_prog *bpf_prog_realloc(struct bpf_prog *fp_old, unsigned int size, 397 gfp_t gfp_extra_flags); 398 void __bpf_prog_free(struct bpf_prog *fp); 399 400 static inline void bpf_prog_unlock_free(struct bpf_prog *fp) 401 { 402 bpf_prog_unlock_ro(fp); 403 __bpf_prog_free(fp); 404 } 405 406 typedef int (*bpf_aux_classic_check_t)(struct sock_filter *filter, 407 unsigned int flen); 408 409 int bpf_prog_create(struct bpf_prog **pfp, struct sock_fprog_kern *fprog); 410 int bpf_prog_create_from_user(struct bpf_prog **pfp, struct sock_fprog *fprog, 411 bpf_aux_classic_check_t trans); 412 void bpf_prog_destroy(struct bpf_prog *fp); 413 414 int sk_attach_filter(struct sock_fprog *fprog, struct sock *sk); 415 int sk_attach_bpf(u32 ufd, struct sock *sk); 416 int sk_detach_filter(struct sock *sk); 417 int sk_get_filter(struct sock *sk, struct sock_filter __user *filter, 418 unsigned int len); 419 420 bool sk_filter_charge(struct sock *sk, struct sk_filter *fp); 421 void sk_filter_uncharge(struct sock *sk, struct sk_filter *fp); 422 423 u64 __bpf_call_base(u64 r1, u64 r2, u64 r3, u64 r4, u64 r5); 424 void bpf_int_jit_compile(struct bpf_prog *fp); 425 bool bpf_helper_changes_skb_data(void *func); 426 427 #ifdef CONFIG_BPF_JIT 428 typedef void (*bpf_jit_fill_hole_t)(void *area, unsigned int size); 429 430 struct bpf_binary_header * 431 bpf_jit_binary_alloc(unsigned int proglen, u8 **image_ptr, 432 unsigned int alignment, 433 bpf_jit_fill_hole_t bpf_fill_ill_insns); 434 void bpf_jit_binary_free(struct bpf_binary_header *hdr); 435 436 void bpf_jit_compile(struct bpf_prog *fp); 437 void bpf_jit_free(struct bpf_prog *fp); 438 439 static inline void bpf_jit_dump(unsigned int flen, unsigned int proglen, 440 u32 pass, void *image) 441 { 442 pr_err("flen=%u proglen=%u pass=%u image=%pK from=%s pid=%d\n", flen, 443 proglen, pass, image, current->comm, task_pid_nr(current)); 444 445 if (image) 446 print_hex_dump(KERN_ERR, "JIT code: ", DUMP_PREFIX_OFFSET, 447 16, 1, image, proglen, false); 448 } 449 #else 450 static inline void bpf_jit_compile(struct bpf_prog *fp) 451 { 452 } 453 454 static inline void bpf_jit_free(struct bpf_prog *fp) 455 { 456 bpf_prog_unlock_free(fp); 457 } 458 #endif /* CONFIG_BPF_JIT */ 459 460 #define BPF_ANC BIT(15) 461 462 static inline u16 bpf_anc_helper(const struct sock_filter *ftest) 463 { 464 BUG_ON(ftest->code & BPF_ANC); 465 466 switch (ftest->code) { 467 case BPF_LD | BPF_W | BPF_ABS: 468 case BPF_LD | BPF_H | BPF_ABS: 469 case BPF_LD | BPF_B | BPF_ABS: 470 #define BPF_ANCILLARY(CODE) case SKF_AD_OFF + SKF_AD_##CODE: \ 471 return BPF_ANC | SKF_AD_##CODE 472 switch (ftest->k) { 473 BPF_ANCILLARY(PROTOCOL); 474 BPF_ANCILLARY(PKTTYPE); 475 BPF_ANCILLARY(IFINDEX); 476 BPF_ANCILLARY(NLATTR); 477 BPF_ANCILLARY(NLATTR_NEST); 478 BPF_ANCILLARY(MARK); 479 BPF_ANCILLARY(QUEUE); 480 BPF_ANCILLARY(HATYPE); 481 BPF_ANCILLARY(RXHASH); 482 BPF_ANCILLARY(CPU); 483 BPF_ANCILLARY(ALU_XOR_X); 484 BPF_ANCILLARY(VLAN_TAG); 485 BPF_ANCILLARY(VLAN_TAG_PRESENT); 486 BPF_ANCILLARY(PAY_OFFSET); 487 BPF_ANCILLARY(RANDOM); 488 BPF_ANCILLARY(VLAN_TPID); 489 } 490 /* Fallthrough. */ 491 default: 492 return ftest->code; 493 } 494 } 495 496 void *bpf_internal_load_pointer_neg_helper(const struct sk_buff *skb, 497 int k, unsigned int size); 498 499 static inline void *bpf_load_pointer(const struct sk_buff *skb, int k, 500 unsigned int size, void *buffer) 501 { 502 if (k >= 0) 503 return skb_header_pointer(skb, k, size, buffer); 504 505 return bpf_internal_load_pointer_neg_helper(skb, k, size); 506 } 507 508 static inline int bpf_tell_extensions(void) 509 { 510 return SKF_AD_MAX; 511 } 512 513 #endif /* __LINUX_FILTER_H__ */ 514