1 /* 2 * Linux Socket Filter - Kernel level socket filtering 3 * 4 * Based on the design of the Berkeley Packet Filter. The new 5 * internal format has been designed by PLUMgrid: 6 * 7 * Copyright (c) 2011 - 2014 PLUMgrid, http://plumgrid.com 8 * 9 * Authors: 10 * 11 * Jay Schulist <jschlst@samba.org> 12 * Alexei Starovoitov <ast@plumgrid.com> 13 * Daniel Borkmann <dborkman@redhat.com> 14 * 15 * This program is free software; you can redistribute it and/or 16 * modify it under the terms of the GNU General Public License 17 * as published by the Free Software Foundation; either version 18 * 2 of the License, or (at your option) any later version. 19 * 20 * Andi Kleen - Fix a few bad bugs and races. 21 * Kris Katterjohn - Added many additional checks in bpf_check_classic() 22 */ 23 24 #include <linux/filter.h> 25 #include <linux/skbuff.h> 26 #include <linux/vmalloc.h> 27 #include <linux/random.h> 28 #include <linux/moduleloader.h> 29 #include <linux/bpf.h> 30 31 #include <asm/unaligned.h> 32 33 /* Registers */ 34 #define BPF_R0 regs[BPF_REG_0] 35 #define BPF_R1 regs[BPF_REG_1] 36 #define BPF_R2 regs[BPF_REG_2] 37 #define BPF_R3 regs[BPF_REG_3] 38 #define BPF_R4 regs[BPF_REG_4] 39 #define BPF_R5 regs[BPF_REG_5] 40 #define BPF_R6 regs[BPF_REG_6] 41 #define BPF_R7 regs[BPF_REG_7] 42 #define BPF_R8 regs[BPF_REG_8] 43 #define BPF_R9 regs[BPF_REG_9] 44 #define BPF_R10 regs[BPF_REG_10] 45 46 /* Named registers */ 47 #define DST regs[insn->dst_reg] 48 #define SRC regs[insn->src_reg] 49 #define FP regs[BPF_REG_FP] 50 #define ARG1 regs[BPF_REG_ARG1] 51 #define CTX regs[BPF_REG_CTX] 52 #define IMM insn->imm 53 54 /* No hurry in this branch 55 * 56 * Exported for the bpf jit load helper. 57 */ 58 void *bpf_internal_load_pointer_neg_helper(const struct sk_buff *skb, int k, unsigned int size) 59 { 60 u8 *ptr = NULL; 61 62 if (k >= SKF_NET_OFF) 63 ptr = skb_network_header(skb) + k - SKF_NET_OFF; 64 else if (k >= SKF_LL_OFF) 65 ptr = skb_mac_header(skb) + k - SKF_LL_OFF; 66 67 if (ptr >= skb->head && ptr + size <= skb_tail_pointer(skb)) 68 return ptr; 69 70 return NULL; 71 } 72 73 struct bpf_prog *bpf_prog_alloc(unsigned int size, gfp_t gfp_extra_flags) 74 { 75 gfp_t gfp_flags = GFP_KERNEL | __GFP_HIGHMEM | __GFP_ZERO | 76 gfp_extra_flags; 77 struct bpf_prog_aux *aux; 78 struct bpf_prog *fp; 79 80 size = round_up(size, PAGE_SIZE); 81 fp = __vmalloc(size, gfp_flags, PAGE_KERNEL); 82 if (fp == NULL) 83 return NULL; 84 85 aux = kzalloc(sizeof(*aux), GFP_KERNEL | gfp_extra_flags); 86 if (aux == NULL) { 87 vfree(fp); 88 return NULL; 89 } 90 91 fp->pages = size / PAGE_SIZE; 92 fp->aux = aux; 93 94 return fp; 95 } 96 EXPORT_SYMBOL_GPL(bpf_prog_alloc); 97 98 struct bpf_prog *bpf_prog_realloc(struct bpf_prog *fp_old, unsigned int size, 99 gfp_t gfp_extra_flags) 100 { 101 gfp_t gfp_flags = GFP_KERNEL | __GFP_HIGHMEM | __GFP_ZERO | 102 gfp_extra_flags; 103 struct bpf_prog *fp; 104 105 BUG_ON(fp_old == NULL); 106 107 size = round_up(size, PAGE_SIZE); 108 if (size <= fp_old->pages * PAGE_SIZE) 109 return fp_old; 110 111 fp = __vmalloc(size, gfp_flags, PAGE_KERNEL); 112 if (fp != NULL) { 113 memcpy(fp, fp_old, fp_old->pages * PAGE_SIZE); 114 fp->pages = size / PAGE_SIZE; 115 116 /* We keep fp->aux from fp_old around in the new 117 * reallocated structure. 118 */ 119 fp_old->aux = NULL; 120 __bpf_prog_free(fp_old); 121 } 122 123 return fp; 124 } 125 EXPORT_SYMBOL_GPL(bpf_prog_realloc); 126 127 void __bpf_prog_free(struct bpf_prog *fp) 128 { 129 kfree(fp->aux); 130 vfree(fp); 131 } 132 EXPORT_SYMBOL_GPL(__bpf_prog_free); 133 134 #ifdef CONFIG_BPF_JIT 135 struct bpf_binary_header * 136 bpf_jit_binary_alloc(unsigned int proglen, u8 **image_ptr, 137 unsigned int alignment, 138 bpf_jit_fill_hole_t bpf_fill_ill_insns) 139 { 140 struct bpf_binary_header *hdr; 141 unsigned int size, hole, start; 142 143 /* Most of BPF filters are really small, but if some of them 144 * fill a page, allow at least 128 extra bytes to insert a 145 * random section of illegal instructions. 146 */ 147 size = round_up(proglen + sizeof(*hdr) + 128, PAGE_SIZE); 148 hdr = module_alloc(size); 149 if (hdr == NULL) 150 return NULL; 151 152 /* Fill space with illegal/arch-dep instructions. */ 153 bpf_fill_ill_insns(hdr, size); 154 155 hdr->pages = size / PAGE_SIZE; 156 hole = min_t(unsigned int, size - (proglen + sizeof(*hdr)), 157 PAGE_SIZE - sizeof(*hdr)); 158 start = (prandom_u32() % hole) & ~(alignment - 1); 159 160 /* Leave a random number of instructions before BPF code. */ 161 *image_ptr = &hdr->image[start]; 162 163 return hdr; 164 } 165 166 void bpf_jit_binary_free(struct bpf_binary_header *hdr) 167 { 168 module_memfree(hdr); 169 } 170 #endif /* CONFIG_BPF_JIT */ 171 172 /* Base function for offset calculation. Needs to go into .text section, 173 * therefore keeping it non-static as well; will also be used by JITs 174 * anyway later on, so do not let the compiler omit it. 175 */ 176 noinline u64 __bpf_call_base(u64 r1, u64 r2, u64 r3, u64 r4, u64 r5) 177 { 178 return 0; 179 } 180 181 /** 182 * __bpf_prog_run - run eBPF program on a given context 183 * @ctx: is the data we are operating on 184 * @insn: is the array of eBPF instructions 185 * 186 * Decode and execute eBPF instructions. 187 */ 188 static unsigned int __bpf_prog_run(void *ctx, const struct bpf_insn *insn) 189 { 190 u64 stack[MAX_BPF_STACK / sizeof(u64)]; 191 u64 regs[MAX_BPF_REG], tmp; 192 static const void *jumptable[256] = { 193 [0 ... 255] = &&default_label, 194 /* Now overwrite non-defaults ... */ 195 /* 32 bit ALU operations */ 196 [BPF_ALU | BPF_ADD | BPF_X] = &&ALU_ADD_X, 197 [BPF_ALU | BPF_ADD | BPF_K] = &&ALU_ADD_K, 198 [BPF_ALU | BPF_SUB | BPF_X] = &&ALU_SUB_X, 199 [BPF_ALU | BPF_SUB | BPF_K] = &&ALU_SUB_K, 200 [BPF_ALU | BPF_AND | BPF_X] = &&ALU_AND_X, 201 [BPF_ALU | BPF_AND | BPF_K] = &&ALU_AND_K, 202 [BPF_ALU | BPF_OR | BPF_X] = &&ALU_OR_X, 203 [BPF_ALU | BPF_OR | BPF_K] = &&ALU_OR_K, 204 [BPF_ALU | BPF_LSH | BPF_X] = &&ALU_LSH_X, 205 [BPF_ALU | BPF_LSH | BPF_K] = &&ALU_LSH_K, 206 [BPF_ALU | BPF_RSH | BPF_X] = &&ALU_RSH_X, 207 [BPF_ALU | BPF_RSH | BPF_K] = &&ALU_RSH_K, 208 [BPF_ALU | BPF_XOR | BPF_X] = &&ALU_XOR_X, 209 [BPF_ALU | BPF_XOR | BPF_K] = &&ALU_XOR_K, 210 [BPF_ALU | BPF_MUL | BPF_X] = &&ALU_MUL_X, 211 [BPF_ALU | BPF_MUL | BPF_K] = &&ALU_MUL_K, 212 [BPF_ALU | BPF_MOV | BPF_X] = &&ALU_MOV_X, 213 [BPF_ALU | BPF_MOV | BPF_K] = &&ALU_MOV_K, 214 [BPF_ALU | BPF_DIV | BPF_X] = &&ALU_DIV_X, 215 [BPF_ALU | BPF_DIV | BPF_K] = &&ALU_DIV_K, 216 [BPF_ALU | BPF_MOD | BPF_X] = &&ALU_MOD_X, 217 [BPF_ALU | BPF_MOD | BPF_K] = &&ALU_MOD_K, 218 [BPF_ALU | BPF_NEG] = &&ALU_NEG, 219 [BPF_ALU | BPF_END | BPF_TO_BE] = &&ALU_END_TO_BE, 220 [BPF_ALU | BPF_END | BPF_TO_LE] = &&ALU_END_TO_LE, 221 /* 64 bit ALU operations */ 222 [BPF_ALU64 | BPF_ADD | BPF_X] = &&ALU64_ADD_X, 223 [BPF_ALU64 | BPF_ADD | BPF_K] = &&ALU64_ADD_K, 224 [BPF_ALU64 | BPF_SUB | BPF_X] = &&ALU64_SUB_X, 225 [BPF_ALU64 | BPF_SUB | BPF_K] = &&ALU64_SUB_K, 226 [BPF_ALU64 | BPF_AND | BPF_X] = &&ALU64_AND_X, 227 [BPF_ALU64 | BPF_AND | BPF_K] = &&ALU64_AND_K, 228 [BPF_ALU64 | BPF_OR | BPF_X] = &&ALU64_OR_X, 229 [BPF_ALU64 | BPF_OR | BPF_K] = &&ALU64_OR_K, 230 [BPF_ALU64 | BPF_LSH | BPF_X] = &&ALU64_LSH_X, 231 [BPF_ALU64 | BPF_LSH | BPF_K] = &&ALU64_LSH_K, 232 [BPF_ALU64 | BPF_RSH | BPF_X] = &&ALU64_RSH_X, 233 [BPF_ALU64 | BPF_RSH | BPF_K] = &&ALU64_RSH_K, 234 [BPF_ALU64 | BPF_XOR | BPF_X] = &&ALU64_XOR_X, 235 [BPF_ALU64 | BPF_XOR | BPF_K] = &&ALU64_XOR_K, 236 [BPF_ALU64 | BPF_MUL | BPF_X] = &&ALU64_MUL_X, 237 [BPF_ALU64 | BPF_MUL | BPF_K] = &&ALU64_MUL_K, 238 [BPF_ALU64 | BPF_MOV | BPF_X] = &&ALU64_MOV_X, 239 [BPF_ALU64 | BPF_MOV | BPF_K] = &&ALU64_MOV_K, 240 [BPF_ALU64 | BPF_ARSH | BPF_X] = &&ALU64_ARSH_X, 241 [BPF_ALU64 | BPF_ARSH | BPF_K] = &&ALU64_ARSH_K, 242 [BPF_ALU64 | BPF_DIV | BPF_X] = &&ALU64_DIV_X, 243 [BPF_ALU64 | BPF_DIV | BPF_K] = &&ALU64_DIV_K, 244 [BPF_ALU64 | BPF_MOD | BPF_X] = &&ALU64_MOD_X, 245 [BPF_ALU64 | BPF_MOD | BPF_K] = &&ALU64_MOD_K, 246 [BPF_ALU64 | BPF_NEG] = &&ALU64_NEG, 247 /* Call instruction */ 248 [BPF_JMP | BPF_CALL] = &&JMP_CALL, 249 [BPF_JMP | BPF_CALL | BPF_X] = &&JMP_TAIL_CALL, 250 /* Jumps */ 251 [BPF_JMP | BPF_JA] = &&JMP_JA, 252 [BPF_JMP | BPF_JEQ | BPF_X] = &&JMP_JEQ_X, 253 [BPF_JMP | BPF_JEQ | BPF_K] = &&JMP_JEQ_K, 254 [BPF_JMP | BPF_JNE | BPF_X] = &&JMP_JNE_X, 255 [BPF_JMP | BPF_JNE | BPF_K] = &&JMP_JNE_K, 256 [BPF_JMP | BPF_JGT | BPF_X] = &&JMP_JGT_X, 257 [BPF_JMP | BPF_JGT | BPF_K] = &&JMP_JGT_K, 258 [BPF_JMP | BPF_JGE | BPF_X] = &&JMP_JGE_X, 259 [BPF_JMP | BPF_JGE | BPF_K] = &&JMP_JGE_K, 260 [BPF_JMP | BPF_JSGT | BPF_X] = &&JMP_JSGT_X, 261 [BPF_JMP | BPF_JSGT | BPF_K] = &&JMP_JSGT_K, 262 [BPF_JMP | BPF_JSGE | BPF_X] = &&JMP_JSGE_X, 263 [BPF_JMP | BPF_JSGE | BPF_K] = &&JMP_JSGE_K, 264 [BPF_JMP | BPF_JSET | BPF_X] = &&JMP_JSET_X, 265 [BPF_JMP | BPF_JSET | BPF_K] = &&JMP_JSET_K, 266 /* Program return */ 267 [BPF_JMP | BPF_EXIT] = &&JMP_EXIT, 268 /* Store instructions */ 269 [BPF_STX | BPF_MEM | BPF_B] = &&STX_MEM_B, 270 [BPF_STX | BPF_MEM | BPF_H] = &&STX_MEM_H, 271 [BPF_STX | BPF_MEM | BPF_W] = &&STX_MEM_W, 272 [BPF_STX | BPF_MEM | BPF_DW] = &&STX_MEM_DW, 273 [BPF_STX | BPF_XADD | BPF_W] = &&STX_XADD_W, 274 [BPF_STX | BPF_XADD | BPF_DW] = &&STX_XADD_DW, 275 [BPF_ST | BPF_MEM | BPF_B] = &&ST_MEM_B, 276 [BPF_ST | BPF_MEM | BPF_H] = &&ST_MEM_H, 277 [BPF_ST | BPF_MEM | BPF_W] = &&ST_MEM_W, 278 [BPF_ST | BPF_MEM | BPF_DW] = &&ST_MEM_DW, 279 /* Load instructions */ 280 [BPF_LDX | BPF_MEM | BPF_B] = &&LDX_MEM_B, 281 [BPF_LDX | BPF_MEM | BPF_H] = &&LDX_MEM_H, 282 [BPF_LDX | BPF_MEM | BPF_W] = &&LDX_MEM_W, 283 [BPF_LDX | BPF_MEM | BPF_DW] = &&LDX_MEM_DW, 284 [BPF_LD | BPF_ABS | BPF_W] = &&LD_ABS_W, 285 [BPF_LD | BPF_ABS | BPF_H] = &&LD_ABS_H, 286 [BPF_LD | BPF_ABS | BPF_B] = &&LD_ABS_B, 287 [BPF_LD | BPF_IND | BPF_W] = &&LD_IND_W, 288 [BPF_LD | BPF_IND | BPF_H] = &&LD_IND_H, 289 [BPF_LD | BPF_IND | BPF_B] = &&LD_IND_B, 290 [BPF_LD | BPF_IMM | BPF_DW] = &&LD_IMM_DW, 291 }; 292 u32 tail_call_cnt = 0; 293 void *ptr; 294 int off; 295 296 #define CONT ({ insn++; goto select_insn; }) 297 #define CONT_JMP ({ insn++; goto select_insn; }) 298 299 FP = (u64) (unsigned long) &stack[ARRAY_SIZE(stack)]; 300 ARG1 = (u64) (unsigned long) ctx; 301 302 /* Registers used in classic BPF programs need to be reset first. */ 303 regs[BPF_REG_A] = 0; 304 regs[BPF_REG_X] = 0; 305 306 select_insn: 307 goto *jumptable[insn->code]; 308 309 /* ALU */ 310 #define ALU(OPCODE, OP) \ 311 ALU64_##OPCODE##_X: \ 312 DST = DST OP SRC; \ 313 CONT; \ 314 ALU_##OPCODE##_X: \ 315 DST = (u32) DST OP (u32) SRC; \ 316 CONT; \ 317 ALU64_##OPCODE##_K: \ 318 DST = DST OP IMM; \ 319 CONT; \ 320 ALU_##OPCODE##_K: \ 321 DST = (u32) DST OP (u32) IMM; \ 322 CONT; 323 324 ALU(ADD, +) 325 ALU(SUB, -) 326 ALU(AND, &) 327 ALU(OR, |) 328 ALU(LSH, <<) 329 ALU(RSH, >>) 330 ALU(XOR, ^) 331 ALU(MUL, *) 332 #undef ALU 333 ALU_NEG: 334 DST = (u32) -DST; 335 CONT; 336 ALU64_NEG: 337 DST = -DST; 338 CONT; 339 ALU_MOV_X: 340 DST = (u32) SRC; 341 CONT; 342 ALU_MOV_K: 343 DST = (u32) IMM; 344 CONT; 345 ALU64_MOV_X: 346 DST = SRC; 347 CONT; 348 ALU64_MOV_K: 349 DST = IMM; 350 CONT; 351 LD_IMM_DW: 352 DST = (u64) (u32) insn[0].imm | ((u64) (u32) insn[1].imm) << 32; 353 insn++; 354 CONT; 355 ALU64_ARSH_X: 356 (*(s64 *) &DST) >>= SRC; 357 CONT; 358 ALU64_ARSH_K: 359 (*(s64 *) &DST) >>= IMM; 360 CONT; 361 ALU64_MOD_X: 362 if (unlikely(SRC == 0)) 363 return 0; 364 div64_u64_rem(DST, SRC, &tmp); 365 DST = tmp; 366 CONT; 367 ALU_MOD_X: 368 if (unlikely(SRC == 0)) 369 return 0; 370 tmp = (u32) DST; 371 DST = do_div(tmp, (u32) SRC); 372 CONT; 373 ALU64_MOD_K: 374 div64_u64_rem(DST, IMM, &tmp); 375 DST = tmp; 376 CONT; 377 ALU_MOD_K: 378 tmp = (u32) DST; 379 DST = do_div(tmp, (u32) IMM); 380 CONT; 381 ALU64_DIV_X: 382 if (unlikely(SRC == 0)) 383 return 0; 384 DST = div64_u64(DST, SRC); 385 CONT; 386 ALU_DIV_X: 387 if (unlikely(SRC == 0)) 388 return 0; 389 tmp = (u32) DST; 390 do_div(tmp, (u32) SRC); 391 DST = (u32) tmp; 392 CONT; 393 ALU64_DIV_K: 394 DST = div64_u64(DST, IMM); 395 CONT; 396 ALU_DIV_K: 397 tmp = (u32) DST; 398 do_div(tmp, (u32) IMM); 399 DST = (u32) tmp; 400 CONT; 401 ALU_END_TO_BE: 402 switch (IMM) { 403 case 16: 404 DST = (__force u16) cpu_to_be16(DST); 405 break; 406 case 32: 407 DST = (__force u32) cpu_to_be32(DST); 408 break; 409 case 64: 410 DST = (__force u64) cpu_to_be64(DST); 411 break; 412 } 413 CONT; 414 ALU_END_TO_LE: 415 switch (IMM) { 416 case 16: 417 DST = (__force u16) cpu_to_le16(DST); 418 break; 419 case 32: 420 DST = (__force u32) cpu_to_le32(DST); 421 break; 422 case 64: 423 DST = (__force u64) cpu_to_le64(DST); 424 break; 425 } 426 CONT; 427 428 /* CALL */ 429 JMP_CALL: 430 /* Function call scratches BPF_R1-BPF_R5 registers, 431 * preserves BPF_R6-BPF_R9, and stores return value 432 * into BPF_R0. 433 */ 434 BPF_R0 = (__bpf_call_base + insn->imm)(BPF_R1, BPF_R2, BPF_R3, 435 BPF_R4, BPF_R5); 436 CONT; 437 438 JMP_TAIL_CALL: { 439 struct bpf_map *map = (struct bpf_map *) (unsigned long) BPF_R2; 440 struct bpf_array *array = container_of(map, struct bpf_array, map); 441 struct bpf_prog *prog; 442 u64 index = BPF_R3; 443 444 if (unlikely(index >= array->map.max_entries)) 445 goto out; 446 447 if (unlikely(tail_call_cnt > MAX_TAIL_CALL_CNT)) 448 goto out; 449 450 tail_call_cnt++; 451 452 prog = READ_ONCE(array->prog[index]); 453 if (unlikely(!prog)) 454 goto out; 455 456 ARG1 = BPF_R1; 457 insn = prog->insnsi; 458 goto select_insn; 459 out: 460 CONT; 461 } 462 /* JMP */ 463 JMP_JA: 464 insn += insn->off; 465 CONT; 466 JMP_JEQ_X: 467 if (DST == SRC) { 468 insn += insn->off; 469 CONT_JMP; 470 } 471 CONT; 472 JMP_JEQ_K: 473 if (DST == IMM) { 474 insn += insn->off; 475 CONT_JMP; 476 } 477 CONT; 478 JMP_JNE_X: 479 if (DST != SRC) { 480 insn += insn->off; 481 CONT_JMP; 482 } 483 CONT; 484 JMP_JNE_K: 485 if (DST != IMM) { 486 insn += insn->off; 487 CONT_JMP; 488 } 489 CONT; 490 JMP_JGT_X: 491 if (DST > SRC) { 492 insn += insn->off; 493 CONT_JMP; 494 } 495 CONT; 496 JMP_JGT_K: 497 if (DST > IMM) { 498 insn += insn->off; 499 CONT_JMP; 500 } 501 CONT; 502 JMP_JGE_X: 503 if (DST >= SRC) { 504 insn += insn->off; 505 CONT_JMP; 506 } 507 CONT; 508 JMP_JGE_K: 509 if (DST >= IMM) { 510 insn += insn->off; 511 CONT_JMP; 512 } 513 CONT; 514 JMP_JSGT_X: 515 if (((s64) DST) > ((s64) SRC)) { 516 insn += insn->off; 517 CONT_JMP; 518 } 519 CONT; 520 JMP_JSGT_K: 521 if (((s64) DST) > ((s64) IMM)) { 522 insn += insn->off; 523 CONT_JMP; 524 } 525 CONT; 526 JMP_JSGE_X: 527 if (((s64) DST) >= ((s64) SRC)) { 528 insn += insn->off; 529 CONT_JMP; 530 } 531 CONT; 532 JMP_JSGE_K: 533 if (((s64) DST) >= ((s64) IMM)) { 534 insn += insn->off; 535 CONT_JMP; 536 } 537 CONT; 538 JMP_JSET_X: 539 if (DST & SRC) { 540 insn += insn->off; 541 CONT_JMP; 542 } 543 CONT; 544 JMP_JSET_K: 545 if (DST & IMM) { 546 insn += insn->off; 547 CONT_JMP; 548 } 549 CONT; 550 JMP_EXIT: 551 return BPF_R0; 552 553 /* STX and ST and LDX*/ 554 #define LDST(SIZEOP, SIZE) \ 555 STX_MEM_##SIZEOP: \ 556 *(SIZE *)(unsigned long) (DST + insn->off) = SRC; \ 557 CONT; \ 558 ST_MEM_##SIZEOP: \ 559 *(SIZE *)(unsigned long) (DST + insn->off) = IMM; \ 560 CONT; \ 561 LDX_MEM_##SIZEOP: \ 562 DST = *(SIZE *)(unsigned long) (SRC + insn->off); \ 563 CONT; 564 565 LDST(B, u8) 566 LDST(H, u16) 567 LDST(W, u32) 568 LDST(DW, u64) 569 #undef LDST 570 STX_XADD_W: /* lock xadd *(u32 *)(dst_reg + off16) += src_reg */ 571 atomic_add((u32) SRC, (atomic_t *)(unsigned long) 572 (DST + insn->off)); 573 CONT; 574 STX_XADD_DW: /* lock xadd *(u64 *)(dst_reg + off16) += src_reg */ 575 atomic64_add((u64) SRC, (atomic64_t *)(unsigned long) 576 (DST + insn->off)); 577 CONT; 578 LD_ABS_W: /* BPF_R0 = ntohl(*(u32 *) (skb->data + imm32)) */ 579 off = IMM; 580 load_word: 581 /* BPF_LD + BPD_ABS and BPF_LD + BPF_IND insns are 582 * only appearing in the programs where ctx == 583 * skb. All programs keep 'ctx' in regs[BPF_REG_CTX] 584 * == BPF_R6, bpf_convert_filter() saves it in BPF_R6, 585 * internal BPF verifier will check that BPF_R6 == 586 * ctx. 587 * 588 * BPF_ABS and BPF_IND are wrappers of function calls, 589 * so they scratch BPF_R1-BPF_R5 registers, preserve 590 * BPF_R6-BPF_R9, and store return value into BPF_R0. 591 * 592 * Implicit input: 593 * ctx == skb == BPF_R6 == CTX 594 * 595 * Explicit input: 596 * SRC == any register 597 * IMM == 32-bit immediate 598 * 599 * Output: 600 * BPF_R0 - 8/16/32-bit skb data converted to cpu endianness 601 */ 602 603 ptr = bpf_load_pointer((struct sk_buff *) (unsigned long) CTX, off, 4, &tmp); 604 if (likely(ptr != NULL)) { 605 BPF_R0 = get_unaligned_be32(ptr); 606 CONT; 607 } 608 609 return 0; 610 LD_ABS_H: /* BPF_R0 = ntohs(*(u16 *) (skb->data + imm32)) */ 611 off = IMM; 612 load_half: 613 ptr = bpf_load_pointer((struct sk_buff *) (unsigned long) CTX, off, 2, &tmp); 614 if (likely(ptr != NULL)) { 615 BPF_R0 = get_unaligned_be16(ptr); 616 CONT; 617 } 618 619 return 0; 620 LD_ABS_B: /* BPF_R0 = *(u8 *) (skb->data + imm32) */ 621 off = IMM; 622 load_byte: 623 ptr = bpf_load_pointer((struct sk_buff *) (unsigned long) CTX, off, 1, &tmp); 624 if (likely(ptr != NULL)) { 625 BPF_R0 = *(u8 *)ptr; 626 CONT; 627 } 628 629 return 0; 630 LD_IND_W: /* BPF_R0 = ntohl(*(u32 *) (skb->data + src_reg + imm32)) */ 631 off = IMM + SRC; 632 goto load_word; 633 LD_IND_H: /* BPF_R0 = ntohs(*(u16 *) (skb->data + src_reg + imm32)) */ 634 off = IMM + SRC; 635 goto load_half; 636 LD_IND_B: /* BPF_R0 = *(u8 *) (skb->data + src_reg + imm32) */ 637 off = IMM + SRC; 638 goto load_byte; 639 640 default_label: 641 /* If we ever reach this, we have a bug somewhere. */ 642 WARN_RATELIMIT(1, "unknown opcode %02x\n", insn->code); 643 return 0; 644 } 645 646 bool bpf_prog_array_compatible(struct bpf_array *array, 647 const struct bpf_prog *fp) 648 { 649 if (!array->owner_prog_type) { 650 /* There's no owner yet where we could check for 651 * compatibility. 652 */ 653 array->owner_prog_type = fp->type; 654 array->owner_jited = fp->jited; 655 656 return true; 657 } 658 659 return array->owner_prog_type == fp->type && 660 array->owner_jited == fp->jited; 661 } 662 663 static int bpf_check_tail_call(const struct bpf_prog *fp) 664 { 665 struct bpf_prog_aux *aux = fp->aux; 666 int i; 667 668 for (i = 0; i < aux->used_map_cnt; i++) { 669 struct bpf_map *map = aux->used_maps[i]; 670 struct bpf_array *array; 671 672 if (map->map_type != BPF_MAP_TYPE_PROG_ARRAY) 673 continue; 674 675 array = container_of(map, struct bpf_array, map); 676 if (!bpf_prog_array_compatible(array, fp)) 677 return -EINVAL; 678 } 679 680 return 0; 681 } 682 683 /** 684 * bpf_prog_select_runtime - select exec runtime for BPF program 685 * @fp: bpf_prog populated with internal BPF program 686 * 687 * Try to JIT eBPF program, if JIT is not available, use interpreter. 688 * The BPF program will be executed via BPF_PROG_RUN() macro. 689 */ 690 int bpf_prog_select_runtime(struct bpf_prog *fp) 691 { 692 fp->bpf_func = (void *) __bpf_prog_run; 693 694 bpf_int_jit_compile(fp); 695 bpf_prog_lock_ro(fp); 696 697 /* The tail call compatibility check can only be done at 698 * this late stage as we need to determine, if we deal 699 * with JITed or non JITed program concatenations and not 700 * all eBPF JITs might immediately support all features. 701 */ 702 return bpf_check_tail_call(fp); 703 } 704 EXPORT_SYMBOL_GPL(bpf_prog_select_runtime); 705 706 static void bpf_prog_free_deferred(struct work_struct *work) 707 { 708 struct bpf_prog_aux *aux; 709 710 aux = container_of(work, struct bpf_prog_aux, work); 711 bpf_jit_free(aux->prog); 712 } 713 714 /* Free internal BPF program */ 715 void bpf_prog_free(struct bpf_prog *fp) 716 { 717 struct bpf_prog_aux *aux = fp->aux; 718 719 INIT_WORK(&aux->work, bpf_prog_free_deferred); 720 aux->prog = fp; 721 schedule_work(&aux->work); 722 } 723 EXPORT_SYMBOL_GPL(bpf_prog_free); 724 725 /* Weak definitions of helper functions in case we don't have bpf syscall. */ 726 const struct bpf_func_proto bpf_map_lookup_elem_proto __weak; 727 const struct bpf_func_proto bpf_map_update_elem_proto __weak; 728 const struct bpf_func_proto bpf_map_delete_elem_proto __weak; 729 730 const struct bpf_func_proto bpf_get_prandom_u32_proto __weak; 731 const struct bpf_func_proto bpf_get_smp_processor_id_proto __weak; 732 const struct bpf_func_proto bpf_ktime_get_ns_proto __weak; 733 const struct bpf_func_proto bpf_get_current_pid_tgid_proto __weak; 734 const struct bpf_func_proto bpf_get_current_uid_gid_proto __weak; 735 const struct bpf_func_proto bpf_get_current_comm_proto __weak; 736 const struct bpf_func_proto * __weak bpf_get_trace_printk_proto(void) 737 { 738 return NULL; 739 } 740 741 /* Always built-in helper functions. */ 742 const struct bpf_func_proto bpf_tail_call_proto = { 743 .func = NULL, 744 .gpl_only = false, 745 .ret_type = RET_VOID, 746 .arg1_type = ARG_PTR_TO_CTX, 747 .arg2_type = ARG_CONST_MAP_PTR, 748 .arg3_type = ARG_ANYTHING, 749 }; 750 751 /* For classic BPF JITs that don't implement bpf_int_jit_compile(). */ 752 void __weak bpf_int_jit_compile(struct bpf_prog *prog) 753 { 754 } 755 756 /* To execute LD_ABS/LD_IND instructions __bpf_prog_run() may call 757 * skb_copy_bits(), so provide a weak definition of it for NET-less config. 758 */ 759 int __weak skb_copy_bits(const struct sk_buff *skb, int offset, void *to, 760 int len) 761 { 762 return -EFAULT; 763 } 764