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 EXPORT_SYMBOL_GPL(__bpf_call_base); 181 182 /** 183 * __bpf_prog_run - run eBPF program on a given context 184 * @ctx: is the data we are operating on 185 * @insn: is the array of eBPF instructions 186 * 187 * Decode and execute eBPF instructions. 188 */ 189 static unsigned int __bpf_prog_run(void *ctx, const struct bpf_insn *insn) 190 { 191 u64 stack[MAX_BPF_STACK / sizeof(u64)]; 192 u64 regs[MAX_BPF_REG], tmp; 193 static const void *jumptable[256] = { 194 [0 ... 255] = &&default_label, 195 /* Now overwrite non-defaults ... */ 196 /* 32 bit ALU operations */ 197 [BPF_ALU | BPF_ADD | BPF_X] = &&ALU_ADD_X, 198 [BPF_ALU | BPF_ADD | BPF_K] = &&ALU_ADD_K, 199 [BPF_ALU | BPF_SUB | BPF_X] = &&ALU_SUB_X, 200 [BPF_ALU | BPF_SUB | BPF_K] = &&ALU_SUB_K, 201 [BPF_ALU | BPF_AND | BPF_X] = &&ALU_AND_X, 202 [BPF_ALU | BPF_AND | BPF_K] = &&ALU_AND_K, 203 [BPF_ALU | BPF_OR | BPF_X] = &&ALU_OR_X, 204 [BPF_ALU | BPF_OR | BPF_K] = &&ALU_OR_K, 205 [BPF_ALU | BPF_LSH | BPF_X] = &&ALU_LSH_X, 206 [BPF_ALU | BPF_LSH | BPF_K] = &&ALU_LSH_K, 207 [BPF_ALU | BPF_RSH | BPF_X] = &&ALU_RSH_X, 208 [BPF_ALU | BPF_RSH | BPF_K] = &&ALU_RSH_K, 209 [BPF_ALU | BPF_XOR | BPF_X] = &&ALU_XOR_X, 210 [BPF_ALU | BPF_XOR | BPF_K] = &&ALU_XOR_K, 211 [BPF_ALU | BPF_MUL | BPF_X] = &&ALU_MUL_X, 212 [BPF_ALU | BPF_MUL | BPF_K] = &&ALU_MUL_K, 213 [BPF_ALU | BPF_MOV | BPF_X] = &&ALU_MOV_X, 214 [BPF_ALU | BPF_MOV | BPF_K] = &&ALU_MOV_K, 215 [BPF_ALU | BPF_DIV | BPF_X] = &&ALU_DIV_X, 216 [BPF_ALU | BPF_DIV | BPF_K] = &&ALU_DIV_K, 217 [BPF_ALU | BPF_MOD | BPF_X] = &&ALU_MOD_X, 218 [BPF_ALU | BPF_MOD | BPF_K] = &&ALU_MOD_K, 219 [BPF_ALU | BPF_NEG] = &&ALU_NEG, 220 [BPF_ALU | BPF_END | BPF_TO_BE] = &&ALU_END_TO_BE, 221 [BPF_ALU | BPF_END | BPF_TO_LE] = &&ALU_END_TO_LE, 222 /* 64 bit ALU operations */ 223 [BPF_ALU64 | BPF_ADD | BPF_X] = &&ALU64_ADD_X, 224 [BPF_ALU64 | BPF_ADD | BPF_K] = &&ALU64_ADD_K, 225 [BPF_ALU64 | BPF_SUB | BPF_X] = &&ALU64_SUB_X, 226 [BPF_ALU64 | BPF_SUB | BPF_K] = &&ALU64_SUB_K, 227 [BPF_ALU64 | BPF_AND | BPF_X] = &&ALU64_AND_X, 228 [BPF_ALU64 | BPF_AND | BPF_K] = &&ALU64_AND_K, 229 [BPF_ALU64 | BPF_OR | BPF_X] = &&ALU64_OR_X, 230 [BPF_ALU64 | BPF_OR | BPF_K] = &&ALU64_OR_K, 231 [BPF_ALU64 | BPF_LSH | BPF_X] = &&ALU64_LSH_X, 232 [BPF_ALU64 | BPF_LSH | BPF_K] = &&ALU64_LSH_K, 233 [BPF_ALU64 | BPF_RSH | BPF_X] = &&ALU64_RSH_X, 234 [BPF_ALU64 | BPF_RSH | BPF_K] = &&ALU64_RSH_K, 235 [BPF_ALU64 | BPF_XOR | BPF_X] = &&ALU64_XOR_X, 236 [BPF_ALU64 | BPF_XOR | BPF_K] = &&ALU64_XOR_K, 237 [BPF_ALU64 | BPF_MUL | BPF_X] = &&ALU64_MUL_X, 238 [BPF_ALU64 | BPF_MUL | BPF_K] = &&ALU64_MUL_K, 239 [BPF_ALU64 | BPF_MOV | BPF_X] = &&ALU64_MOV_X, 240 [BPF_ALU64 | BPF_MOV | BPF_K] = &&ALU64_MOV_K, 241 [BPF_ALU64 | BPF_ARSH | BPF_X] = &&ALU64_ARSH_X, 242 [BPF_ALU64 | BPF_ARSH | BPF_K] = &&ALU64_ARSH_K, 243 [BPF_ALU64 | BPF_DIV | BPF_X] = &&ALU64_DIV_X, 244 [BPF_ALU64 | BPF_DIV | BPF_K] = &&ALU64_DIV_K, 245 [BPF_ALU64 | BPF_MOD | BPF_X] = &&ALU64_MOD_X, 246 [BPF_ALU64 | BPF_MOD | BPF_K] = &&ALU64_MOD_K, 247 [BPF_ALU64 | BPF_NEG] = &&ALU64_NEG, 248 /* Call instruction */ 249 [BPF_JMP | BPF_CALL] = &&JMP_CALL, 250 [BPF_JMP | BPF_CALL | BPF_X] = &&JMP_TAIL_CALL, 251 /* Jumps */ 252 [BPF_JMP | BPF_JA] = &&JMP_JA, 253 [BPF_JMP | BPF_JEQ | BPF_X] = &&JMP_JEQ_X, 254 [BPF_JMP | BPF_JEQ | BPF_K] = &&JMP_JEQ_K, 255 [BPF_JMP | BPF_JNE | BPF_X] = &&JMP_JNE_X, 256 [BPF_JMP | BPF_JNE | BPF_K] = &&JMP_JNE_K, 257 [BPF_JMP | BPF_JGT | BPF_X] = &&JMP_JGT_X, 258 [BPF_JMP | BPF_JGT | BPF_K] = &&JMP_JGT_K, 259 [BPF_JMP | BPF_JGE | BPF_X] = &&JMP_JGE_X, 260 [BPF_JMP | BPF_JGE | BPF_K] = &&JMP_JGE_K, 261 [BPF_JMP | BPF_JSGT | BPF_X] = &&JMP_JSGT_X, 262 [BPF_JMP | BPF_JSGT | BPF_K] = &&JMP_JSGT_K, 263 [BPF_JMP | BPF_JSGE | BPF_X] = &&JMP_JSGE_X, 264 [BPF_JMP | BPF_JSGE | BPF_K] = &&JMP_JSGE_K, 265 [BPF_JMP | BPF_JSET | BPF_X] = &&JMP_JSET_X, 266 [BPF_JMP | BPF_JSET | BPF_K] = &&JMP_JSET_K, 267 /* Program return */ 268 [BPF_JMP | BPF_EXIT] = &&JMP_EXIT, 269 /* Store instructions */ 270 [BPF_STX | BPF_MEM | BPF_B] = &&STX_MEM_B, 271 [BPF_STX | BPF_MEM | BPF_H] = &&STX_MEM_H, 272 [BPF_STX | BPF_MEM | BPF_W] = &&STX_MEM_W, 273 [BPF_STX | BPF_MEM | BPF_DW] = &&STX_MEM_DW, 274 [BPF_STX | BPF_XADD | BPF_W] = &&STX_XADD_W, 275 [BPF_STX | BPF_XADD | BPF_DW] = &&STX_XADD_DW, 276 [BPF_ST | BPF_MEM | BPF_B] = &&ST_MEM_B, 277 [BPF_ST | BPF_MEM | BPF_H] = &&ST_MEM_H, 278 [BPF_ST | BPF_MEM | BPF_W] = &&ST_MEM_W, 279 [BPF_ST | BPF_MEM | BPF_DW] = &&ST_MEM_DW, 280 /* Load instructions */ 281 [BPF_LDX | BPF_MEM | BPF_B] = &&LDX_MEM_B, 282 [BPF_LDX | BPF_MEM | BPF_H] = &&LDX_MEM_H, 283 [BPF_LDX | BPF_MEM | BPF_W] = &&LDX_MEM_W, 284 [BPF_LDX | BPF_MEM | BPF_DW] = &&LDX_MEM_DW, 285 [BPF_LD | BPF_ABS | BPF_W] = &&LD_ABS_W, 286 [BPF_LD | BPF_ABS | BPF_H] = &&LD_ABS_H, 287 [BPF_LD | BPF_ABS | BPF_B] = &&LD_ABS_B, 288 [BPF_LD | BPF_IND | BPF_W] = &&LD_IND_W, 289 [BPF_LD | BPF_IND | BPF_H] = &&LD_IND_H, 290 [BPF_LD | BPF_IND | BPF_B] = &&LD_IND_B, 291 [BPF_LD | BPF_IMM | BPF_DW] = &&LD_IMM_DW, 292 }; 293 u32 tail_call_cnt = 0; 294 void *ptr; 295 int off; 296 297 #define CONT ({ insn++; goto select_insn; }) 298 #define CONT_JMP ({ insn++; goto select_insn; }) 299 300 FP = (u64) (unsigned long) &stack[ARRAY_SIZE(stack)]; 301 ARG1 = (u64) (unsigned long) ctx; 302 303 /* Registers used in classic BPF programs need to be reset first. */ 304 regs[BPF_REG_A] = 0; 305 regs[BPF_REG_X] = 0; 306 307 select_insn: 308 goto *jumptable[insn->code]; 309 310 /* ALU */ 311 #define ALU(OPCODE, OP) \ 312 ALU64_##OPCODE##_X: \ 313 DST = DST OP SRC; \ 314 CONT; \ 315 ALU_##OPCODE##_X: \ 316 DST = (u32) DST OP (u32) SRC; \ 317 CONT; \ 318 ALU64_##OPCODE##_K: \ 319 DST = DST OP IMM; \ 320 CONT; \ 321 ALU_##OPCODE##_K: \ 322 DST = (u32) DST OP (u32) IMM; \ 323 CONT; 324 325 ALU(ADD, +) 326 ALU(SUB, -) 327 ALU(AND, &) 328 ALU(OR, |) 329 ALU(LSH, <<) 330 ALU(RSH, >>) 331 ALU(XOR, ^) 332 ALU(MUL, *) 333 #undef ALU 334 ALU_NEG: 335 DST = (u32) -DST; 336 CONT; 337 ALU64_NEG: 338 DST = -DST; 339 CONT; 340 ALU_MOV_X: 341 DST = (u32) SRC; 342 CONT; 343 ALU_MOV_K: 344 DST = (u32) IMM; 345 CONT; 346 ALU64_MOV_X: 347 DST = SRC; 348 CONT; 349 ALU64_MOV_K: 350 DST = IMM; 351 CONT; 352 LD_IMM_DW: 353 DST = (u64) (u32) insn[0].imm | ((u64) (u32) insn[1].imm) << 32; 354 insn++; 355 CONT; 356 ALU64_ARSH_X: 357 (*(s64 *) &DST) >>= SRC; 358 CONT; 359 ALU64_ARSH_K: 360 (*(s64 *) &DST) >>= IMM; 361 CONT; 362 ALU64_MOD_X: 363 if (unlikely(SRC == 0)) 364 return 0; 365 div64_u64_rem(DST, SRC, &tmp); 366 DST = tmp; 367 CONT; 368 ALU_MOD_X: 369 if (unlikely(SRC == 0)) 370 return 0; 371 tmp = (u32) DST; 372 DST = do_div(tmp, (u32) SRC); 373 CONT; 374 ALU64_MOD_K: 375 div64_u64_rem(DST, IMM, &tmp); 376 DST = tmp; 377 CONT; 378 ALU_MOD_K: 379 tmp = (u32) DST; 380 DST = do_div(tmp, (u32) IMM); 381 CONT; 382 ALU64_DIV_X: 383 if (unlikely(SRC == 0)) 384 return 0; 385 DST = div64_u64(DST, SRC); 386 CONT; 387 ALU_DIV_X: 388 if (unlikely(SRC == 0)) 389 return 0; 390 tmp = (u32) DST; 391 do_div(tmp, (u32) SRC); 392 DST = (u32) tmp; 393 CONT; 394 ALU64_DIV_K: 395 DST = div64_u64(DST, IMM); 396 CONT; 397 ALU_DIV_K: 398 tmp = (u32) DST; 399 do_div(tmp, (u32) IMM); 400 DST = (u32) tmp; 401 CONT; 402 ALU_END_TO_BE: 403 switch (IMM) { 404 case 16: 405 DST = (__force u16) cpu_to_be16(DST); 406 break; 407 case 32: 408 DST = (__force u32) cpu_to_be32(DST); 409 break; 410 case 64: 411 DST = (__force u64) cpu_to_be64(DST); 412 break; 413 } 414 CONT; 415 ALU_END_TO_LE: 416 switch (IMM) { 417 case 16: 418 DST = (__force u16) cpu_to_le16(DST); 419 break; 420 case 32: 421 DST = (__force u32) cpu_to_le32(DST); 422 break; 423 case 64: 424 DST = (__force u64) cpu_to_le64(DST); 425 break; 426 } 427 CONT; 428 429 /* CALL */ 430 JMP_CALL: 431 /* Function call scratches BPF_R1-BPF_R5 registers, 432 * preserves BPF_R6-BPF_R9, and stores return value 433 * into BPF_R0. 434 */ 435 BPF_R0 = (__bpf_call_base + insn->imm)(BPF_R1, BPF_R2, BPF_R3, 436 BPF_R4, BPF_R5); 437 CONT; 438 439 JMP_TAIL_CALL: { 440 struct bpf_map *map = (struct bpf_map *) (unsigned long) BPF_R2; 441 struct bpf_array *array = container_of(map, struct bpf_array, map); 442 struct bpf_prog *prog; 443 u64 index = BPF_R3; 444 445 if (unlikely(index >= array->map.max_entries)) 446 goto out; 447 448 if (unlikely(tail_call_cnt > MAX_TAIL_CALL_CNT)) 449 goto out; 450 451 tail_call_cnt++; 452 453 prog = READ_ONCE(array->ptrs[index]); 454 if (unlikely(!prog)) 455 goto out; 456 457 /* ARG1 at this point is guaranteed to point to CTX from 458 * the verifier side due to the fact that the tail call is 459 * handeled like a helper, that is, bpf_tail_call_proto, 460 * where arg1_type is ARG_PTR_TO_CTX. 461 */ 462 insn = prog->insnsi; 463 goto select_insn; 464 out: 465 CONT; 466 } 467 /* JMP */ 468 JMP_JA: 469 insn += insn->off; 470 CONT; 471 JMP_JEQ_X: 472 if (DST == SRC) { 473 insn += insn->off; 474 CONT_JMP; 475 } 476 CONT; 477 JMP_JEQ_K: 478 if (DST == IMM) { 479 insn += insn->off; 480 CONT_JMP; 481 } 482 CONT; 483 JMP_JNE_X: 484 if (DST != SRC) { 485 insn += insn->off; 486 CONT_JMP; 487 } 488 CONT; 489 JMP_JNE_K: 490 if (DST != IMM) { 491 insn += insn->off; 492 CONT_JMP; 493 } 494 CONT; 495 JMP_JGT_X: 496 if (DST > SRC) { 497 insn += insn->off; 498 CONT_JMP; 499 } 500 CONT; 501 JMP_JGT_K: 502 if (DST > IMM) { 503 insn += insn->off; 504 CONT_JMP; 505 } 506 CONT; 507 JMP_JGE_X: 508 if (DST >= SRC) { 509 insn += insn->off; 510 CONT_JMP; 511 } 512 CONT; 513 JMP_JGE_K: 514 if (DST >= IMM) { 515 insn += insn->off; 516 CONT_JMP; 517 } 518 CONT; 519 JMP_JSGT_X: 520 if (((s64) DST) > ((s64) SRC)) { 521 insn += insn->off; 522 CONT_JMP; 523 } 524 CONT; 525 JMP_JSGT_K: 526 if (((s64) DST) > ((s64) IMM)) { 527 insn += insn->off; 528 CONT_JMP; 529 } 530 CONT; 531 JMP_JSGE_X: 532 if (((s64) DST) >= ((s64) SRC)) { 533 insn += insn->off; 534 CONT_JMP; 535 } 536 CONT; 537 JMP_JSGE_K: 538 if (((s64) DST) >= ((s64) IMM)) { 539 insn += insn->off; 540 CONT_JMP; 541 } 542 CONT; 543 JMP_JSET_X: 544 if (DST & SRC) { 545 insn += insn->off; 546 CONT_JMP; 547 } 548 CONT; 549 JMP_JSET_K: 550 if (DST & IMM) { 551 insn += insn->off; 552 CONT_JMP; 553 } 554 CONT; 555 JMP_EXIT: 556 return BPF_R0; 557 558 /* STX and ST and LDX*/ 559 #define LDST(SIZEOP, SIZE) \ 560 STX_MEM_##SIZEOP: \ 561 *(SIZE *)(unsigned long) (DST + insn->off) = SRC; \ 562 CONT; \ 563 ST_MEM_##SIZEOP: \ 564 *(SIZE *)(unsigned long) (DST + insn->off) = IMM; \ 565 CONT; \ 566 LDX_MEM_##SIZEOP: \ 567 DST = *(SIZE *)(unsigned long) (SRC + insn->off); \ 568 CONT; 569 570 LDST(B, u8) 571 LDST(H, u16) 572 LDST(W, u32) 573 LDST(DW, u64) 574 #undef LDST 575 STX_XADD_W: /* lock xadd *(u32 *)(dst_reg + off16) += src_reg */ 576 atomic_add((u32) SRC, (atomic_t *)(unsigned long) 577 (DST + insn->off)); 578 CONT; 579 STX_XADD_DW: /* lock xadd *(u64 *)(dst_reg + off16) += src_reg */ 580 atomic64_add((u64) SRC, (atomic64_t *)(unsigned long) 581 (DST + insn->off)); 582 CONT; 583 LD_ABS_W: /* BPF_R0 = ntohl(*(u32 *) (skb->data + imm32)) */ 584 off = IMM; 585 load_word: 586 /* BPF_LD + BPD_ABS and BPF_LD + BPF_IND insns are 587 * only appearing in the programs where ctx == 588 * skb. All programs keep 'ctx' in regs[BPF_REG_CTX] 589 * == BPF_R6, bpf_convert_filter() saves it in BPF_R6, 590 * internal BPF verifier will check that BPF_R6 == 591 * ctx. 592 * 593 * BPF_ABS and BPF_IND are wrappers of function calls, 594 * so they scratch BPF_R1-BPF_R5 registers, preserve 595 * BPF_R6-BPF_R9, and store return value into BPF_R0. 596 * 597 * Implicit input: 598 * ctx == skb == BPF_R6 == CTX 599 * 600 * Explicit input: 601 * SRC == any register 602 * IMM == 32-bit immediate 603 * 604 * Output: 605 * BPF_R0 - 8/16/32-bit skb data converted to cpu endianness 606 */ 607 608 ptr = bpf_load_pointer((struct sk_buff *) (unsigned long) CTX, off, 4, &tmp); 609 if (likely(ptr != NULL)) { 610 BPF_R0 = get_unaligned_be32(ptr); 611 CONT; 612 } 613 614 return 0; 615 LD_ABS_H: /* BPF_R0 = ntohs(*(u16 *) (skb->data + imm32)) */ 616 off = IMM; 617 load_half: 618 ptr = bpf_load_pointer((struct sk_buff *) (unsigned long) CTX, off, 2, &tmp); 619 if (likely(ptr != NULL)) { 620 BPF_R0 = get_unaligned_be16(ptr); 621 CONT; 622 } 623 624 return 0; 625 LD_ABS_B: /* BPF_R0 = *(u8 *) (skb->data + imm32) */ 626 off = IMM; 627 load_byte: 628 ptr = bpf_load_pointer((struct sk_buff *) (unsigned long) CTX, off, 1, &tmp); 629 if (likely(ptr != NULL)) { 630 BPF_R0 = *(u8 *)ptr; 631 CONT; 632 } 633 634 return 0; 635 LD_IND_W: /* BPF_R0 = ntohl(*(u32 *) (skb->data + src_reg + imm32)) */ 636 off = IMM + SRC; 637 goto load_word; 638 LD_IND_H: /* BPF_R0 = ntohs(*(u16 *) (skb->data + src_reg + imm32)) */ 639 off = IMM + SRC; 640 goto load_half; 641 LD_IND_B: /* BPF_R0 = *(u8 *) (skb->data + src_reg + imm32) */ 642 off = IMM + SRC; 643 goto load_byte; 644 645 default_label: 646 /* If we ever reach this, we have a bug somewhere. */ 647 WARN_RATELIMIT(1, "unknown opcode %02x\n", insn->code); 648 return 0; 649 } 650 651 bool bpf_prog_array_compatible(struct bpf_array *array, 652 const struct bpf_prog *fp) 653 { 654 if (!array->owner_prog_type) { 655 /* There's no owner yet where we could check for 656 * compatibility. 657 */ 658 array->owner_prog_type = fp->type; 659 array->owner_jited = fp->jited; 660 661 return true; 662 } 663 664 return array->owner_prog_type == fp->type && 665 array->owner_jited == fp->jited; 666 } 667 668 static int bpf_check_tail_call(const struct bpf_prog *fp) 669 { 670 struct bpf_prog_aux *aux = fp->aux; 671 int i; 672 673 for (i = 0; i < aux->used_map_cnt; i++) { 674 struct bpf_map *map = aux->used_maps[i]; 675 struct bpf_array *array; 676 677 if (map->map_type != BPF_MAP_TYPE_PROG_ARRAY) 678 continue; 679 680 array = container_of(map, struct bpf_array, map); 681 if (!bpf_prog_array_compatible(array, fp)) 682 return -EINVAL; 683 } 684 685 return 0; 686 } 687 688 /** 689 * bpf_prog_select_runtime - select exec runtime for BPF program 690 * @fp: bpf_prog populated with internal BPF program 691 * 692 * Try to JIT eBPF program, if JIT is not available, use interpreter. 693 * The BPF program will be executed via BPF_PROG_RUN() macro. 694 */ 695 int bpf_prog_select_runtime(struct bpf_prog *fp) 696 { 697 fp->bpf_func = (void *) __bpf_prog_run; 698 699 bpf_int_jit_compile(fp); 700 bpf_prog_lock_ro(fp); 701 702 /* The tail call compatibility check can only be done at 703 * this late stage as we need to determine, if we deal 704 * with JITed or non JITed program concatenations and not 705 * all eBPF JITs might immediately support all features. 706 */ 707 return bpf_check_tail_call(fp); 708 } 709 EXPORT_SYMBOL_GPL(bpf_prog_select_runtime); 710 711 static void bpf_prog_free_deferred(struct work_struct *work) 712 { 713 struct bpf_prog_aux *aux; 714 715 aux = container_of(work, struct bpf_prog_aux, work); 716 bpf_jit_free(aux->prog); 717 } 718 719 /* Free internal BPF program */ 720 void bpf_prog_free(struct bpf_prog *fp) 721 { 722 struct bpf_prog_aux *aux = fp->aux; 723 724 INIT_WORK(&aux->work, bpf_prog_free_deferred); 725 aux->prog = fp; 726 schedule_work(&aux->work); 727 } 728 EXPORT_SYMBOL_GPL(bpf_prog_free); 729 730 /* Weak definitions of helper functions in case we don't have bpf syscall. */ 731 const struct bpf_func_proto bpf_map_lookup_elem_proto __weak; 732 const struct bpf_func_proto bpf_map_update_elem_proto __weak; 733 const struct bpf_func_proto bpf_map_delete_elem_proto __weak; 734 735 const struct bpf_func_proto bpf_get_prandom_u32_proto __weak; 736 const struct bpf_func_proto bpf_get_smp_processor_id_proto __weak; 737 const struct bpf_func_proto bpf_ktime_get_ns_proto __weak; 738 const struct bpf_func_proto bpf_get_current_pid_tgid_proto __weak; 739 const struct bpf_func_proto bpf_get_current_uid_gid_proto __weak; 740 const struct bpf_func_proto bpf_get_current_comm_proto __weak; 741 const struct bpf_func_proto * __weak bpf_get_trace_printk_proto(void) 742 { 743 return NULL; 744 } 745 746 /* Always built-in helper functions. */ 747 const struct bpf_func_proto bpf_tail_call_proto = { 748 .func = NULL, 749 .gpl_only = false, 750 .ret_type = RET_VOID, 751 .arg1_type = ARG_PTR_TO_CTX, 752 .arg2_type = ARG_CONST_MAP_PTR, 753 .arg3_type = ARG_ANYTHING, 754 }; 755 756 /* For classic BPF JITs that don't implement bpf_int_jit_compile(). */ 757 void __weak bpf_int_jit_compile(struct bpf_prog *prog) 758 { 759 } 760 761 /* To execute LD_ABS/LD_IND instructions __bpf_prog_run() may call 762 * skb_copy_bits(), so provide a weak definition of it for NET-less config. 763 */ 764 int __weak skb_copy_bits(const struct sk_buff *skb, int offset, void *to, 765 int len) 766 { 767 return -EFAULT; 768 } 769