| 1 | /* |
| 2 | * Copyright (c) 1990, 1991, 1993 |
| 3 | * The Regents of the University of California. All rights reserved. |
| 4 | * |
| 5 | * This code is derived from the Stanford/CMU enet packet filter, |
| 6 | * (net/enet.c) distributed as part of 4.3BSD, and code contributed |
| 7 | * to Berkeley by Steven McCanne and Van Jacobson both of Lawrence |
| 8 | * Berkeley Laboratory. |
| 9 | * |
| 10 | * Redistribution and use in source and binary forms, with or without |
| 11 | * modification, are permitted provided that the following conditions |
| 12 | * are met: |
| 13 | * 1. Redistributions of source code must retain the above copyright |
| 14 | * notice, this list of conditions and the following disclaimer. |
| 15 | * 2. Redistributions in binary form must reproduce the above copyright |
| 16 | * notice, this list of conditions and the following disclaimer in the |
| 17 | * documentation and/or other materials provided with the distribution. |
| 18 | * 3. All advertising materials mentioning features or use of this software |
| 19 | * must display the following acknowledgement: |
| 20 | * This product includes software developed by the University of |
| 21 | * California, Berkeley and its contributors. |
| 22 | * 4. Neither the name of the University nor the names of its contributors |
| 23 | * may be used to endorse or promote products derived from this software |
| 24 | * without specific prior written permission. |
| 25 | * |
| 26 | * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND |
| 27 | * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE |
| 28 | * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE |
| 29 | * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE |
| 30 | * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL |
| 31 | * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS |
| 32 | * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) |
| 33 | * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT |
| 34 | * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY |
| 35 | * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF |
| 36 | * SUCH DAMAGE. |
| 37 | * |
| 38 | * @(#)bpf_filter.c 8.1 (Berkeley) 6/10/93 |
| 39 | * |
| 40 | * $FreeBSD: src/sys/net/bpf_filter.c,v 1.17 1999/12/29 04:38:31 peter Exp $ |
| 41 | */ |
| 42 | |
| 43 | #include <sys/systm.h> |
| 44 | #include <sys/param.h> |
| 45 | |
| 46 | #if defined(sparc) || defined(mips) || defined(ibm032) |
| 47 | #define BPF_ALIGN |
| 48 | #endif |
| 49 | |
| 50 | #ifndef BPF_ALIGN |
| 51 | #define EXTRACT_SHORT(p) ((u_int16_t)ntohs(*(u_int16_t *)p)) |
| 52 | #define EXTRACT_LONG(p) (ntohl(*(u_int32_t *)p)) |
| 53 | #else |
| 54 | #define EXTRACT_SHORT(p)\ |
| 55 | ((u_int16_t)\ |
| 56 | ((u_int16_t)*((u_char *)p+0)<<8|\ |
| 57 | (u_int16_t)*((u_char *)p+1)<<0)) |
| 58 | #define EXTRACT_LONG(p)\ |
| 59 | ((u_int32_t)*((u_char *)p+0)<<24|\ |
| 60 | (u_int32_t)*((u_char *)p+1)<<16|\ |
| 61 | (u_int32_t)*((u_char *)p+2)<<8|\ |
| 62 | (u_int32_t)*((u_char *)p+3)<<0) |
| 63 | #endif |
| 64 | |
| 65 | #ifdef _KERNEL |
| 66 | #include <sys/mbuf.h> |
| 67 | #endif |
| 68 | #include <net/bpf.h> |
| 69 | #ifdef _KERNEL |
| 70 | #define MINDEX(m, k) \ |
| 71 | { \ |
| 72 | int len = m->m_len; \ |
| 73 | \ |
| 74 | while (k >= len) { \ |
| 75 | k -= len; \ |
| 76 | m = m->m_next; \ |
| 77 | if (m == 0) \ |
| 78 | return 0; \ |
| 79 | len = m->m_len; \ |
| 80 | } \ |
| 81 | } |
| 82 | |
| 83 | extern int bpf_maxbufsize; |
| 84 | |
| 85 | static u_int16_t m_xhalf (struct mbuf *m, bpf_u_int32 k, int *err); |
| 86 | static u_int32_t m_xword (struct mbuf *m, bpf_u_int32 k, int *err); |
| 87 | |
| 88 | static u_int32_t |
| 89 | m_xword(struct mbuf *m, bpf_u_int32 k, int *err) |
| 90 | { |
| 91 | size_t len; |
| 92 | u_char *cp, *np; |
| 93 | struct mbuf *m0; |
| 94 | |
| 95 | len = m->m_len; |
| 96 | while (k >= len) { |
| 97 | k -= len; |
| 98 | m = m->m_next; |
| 99 | if (m == NULL) |
| 100 | goto bad; |
| 101 | len = m->m_len; |
| 102 | } |
| 103 | cp = mtod(m, u_char *) + k; |
| 104 | if (len - k >= 4) { |
| 105 | *err = 0; |
| 106 | return EXTRACT_LONG(cp); |
| 107 | } |
| 108 | m0 = m->m_next; |
| 109 | if (m0 == NULL || m0->m_len + len - k < 4) |
| 110 | goto bad; |
| 111 | *err = 0; |
| 112 | np = mtod(m0, u_char *); |
| 113 | switch (len - k) { |
| 114 | |
| 115 | case 1: |
| 116 | return |
| 117 | ((u_int32_t)cp[0] << 24) | |
| 118 | ((u_int32_t)np[0] << 16) | |
| 119 | ((u_int32_t)np[1] << 8) | |
| 120 | (u_int32_t)np[2]; |
| 121 | |
| 122 | case 2: |
| 123 | return |
| 124 | ((u_int32_t)cp[0] << 24) | |
| 125 | ((u_int32_t)cp[1] << 16) | |
| 126 | ((u_int32_t)np[0] << 8) | |
| 127 | (u_int32_t)np[1]; |
| 128 | |
| 129 | default: |
| 130 | return |
| 131 | ((u_int32_t)cp[0] << 24) | |
| 132 | ((u_int32_t)cp[1] << 16) | |
| 133 | ((u_int32_t)cp[2] << 8) | |
| 134 | (u_int32_t)np[0]; |
| 135 | } |
| 136 | bad: |
| 137 | *err = 1; |
| 138 | return 0; |
| 139 | } |
| 140 | |
| 141 | static u_int16_t |
| 142 | m_xhalf(struct mbuf *m, bpf_u_int32 k, int *err) |
| 143 | { |
| 144 | size_t len; |
| 145 | u_char *cp; |
| 146 | struct mbuf *m0; |
| 147 | |
| 148 | len = m->m_len; |
| 149 | while (k >= len) { |
| 150 | k -= len; |
| 151 | m = m->m_next; |
| 152 | if (m == NULL) |
| 153 | goto bad; |
| 154 | len = m->m_len; |
| 155 | } |
| 156 | cp = mtod(m, u_char *) + k; |
| 157 | if (len - k >= 2) { |
| 158 | *err = 0; |
| 159 | return EXTRACT_SHORT(cp); |
| 160 | } |
| 161 | m0 = m->m_next; |
| 162 | if (m0 == NULL) |
| 163 | goto bad; |
| 164 | *err = 0; |
| 165 | return (cp[0] << 8) | mtod(m0, u_char *)[0]; |
| 166 | bad: |
| 167 | *err = 1; |
| 168 | return 0; |
| 169 | } |
| 170 | #endif |
| 171 | |
| 172 | /* |
| 173 | * Execute the filter program starting at pc on the packet p |
| 174 | * wirelen is the length of the original packet |
| 175 | * buflen is the amount of data present |
| 176 | */ |
| 177 | u_int |
| 178 | bpf_filter(const struct bpf_insn *pc, u_char *p, u_int wirelen, u_int buflen) |
| 179 | { |
| 180 | u_int32_t A = 0, X = 0; |
| 181 | bpf_u_int32 k; |
| 182 | int32_t mem[BPF_MEMWORDS]; |
| 183 | |
| 184 | bzero(mem, sizeof(mem)); |
| 185 | |
| 186 | if (pc == NULL) { |
| 187 | /* |
| 188 | * No filter means accept all. |
| 189 | */ |
| 190 | return (u_int)-1; |
| 191 | } |
| 192 | |
| 193 | --pc; |
| 194 | while (1) { |
| 195 | ++pc; |
| 196 | switch (pc->code) { |
| 197 | |
| 198 | default: |
| 199 | #ifdef _KERNEL |
| 200 | return 0; |
| 201 | #else |
| 202 | abort(); |
| 203 | #endif |
| 204 | case BPF_RET|BPF_K: |
| 205 | return (u_int)pc->k; |
| 206 | |
| 207 | case BPF_RET|BPF_A: |
| 208 | return (u_int)A; |
| 209 | |
| 210 | case BPF_LD|BPF_W|BPF_ABS: |
| 211 | k = pc->k; |
| 212 | if (k > buflen || sizeof(int32_t) > buflen - k) { |
| 213 | #ifdef _KERNEL |
| 214 | int merr; |
| 215 | |
| 216 | if (buflen != 0) |
| 217 | return 0; |
| 218 | A = m_xword((struct mbuf *)p, k, &merr); |
| 219 | if (merr != 0) |
| 220 | return 0; |
| 221 | continue; |
| 222 | #else |
| 223 | return 0; |
| 224 | #endif |
| 225 | } |
| 226 | #ifdef BPF_ALIGN |
| 227 | if (((intptr_t)(p + k) & 3) != 0) |
| 228 | A = EXTRACT_LONG(&p[k]); |
| 229 | else |
| 230 | #endif |
| 231 | A = ntohl(*(int32_t *)(p + k)); |
| 232 | continue; |
| 233 | |
| 234 | case BPF_LD|BPF_H|BPF_ABS: |
| 235 | k = pc->k; |
| 236 | if (k > buflen || sizeof(int16_t) > buflen - k) { |
| 237 | #ifdef _KERNEL |
| 238 | int merr; |
| 239 | |
| 240 | if (buflen != 0) |
| 241 | return 0; |
| 242 | A = m_xhalf((struct mbuf *)p, k, &merr); |
| 243 | continue; |
| 244 | #else |
| 245 | return 0; |
| 246 | #endif |
| 247 | } |
| 248 | A = EXTRACT_SHORT(&p[k]); |
| 249 | continue; |
| 250 | |
| 251 | case BPF_LD|BPF_B|BPF_ABS: |
| 252 | k = pc->k; |
| 253 | if (k >= buflen) { |
| 254 | #ifdef _KERNEL |
| 255 | struct mbuf *m; |
| 256 | |
| 257 | if (buflen != 0) |
| 258 | return 0; |
| 259 | m = (struct mbuf *)p; |
| 260 | MINDEX(m, k); |
| 261 | A = mtod(m, u_char *)[k]; |
| 262 | continue; |
| 263 | #else |
| 264 | return 0; |
| 265 | #endif |
| 266 | } |
| 267 | A = p[k]; |
| 268 | continue; |
| 269 | |
| 270 | case BPF_LD|BPF_W|BPF_LEN: |
| 271 | A = wirelen; |
| 272 | continue; |
| 273 | |
| 274 | case BPF_LDX|BPF_W|BPF_LEN: |
| 275 | X = wirelen; |
| 276 | continue; |
| 277 | |
| 278 | case BPF_LD|BPF_W|BPF_IND: |
| 279 | k = X + pc->k; |
| 280 | if (pc->k > buflen || X > buflen - pc->k || |
| 281 | sizeof(int32_t) > buflen - k) { |
| 282 | #ifdef _KERNEL |
| 283 | int merr; |
| 284 | |
| 285 | if (buflen != 0) |
| 286 | return 0; |
| 287 | A = m_xword((struct mbuf *)p, k, &merr); |
| 288 | if (merr != 0) |
| 289 | return 0; |
| 290 | continue; |
| 291 | #else |
| 292 | return 0; |
| 293 | #endif |
| 294 | } |
| 295 | #ifdef BPF_ALIGN |
| 296 | if (((intptr_t)(p + k) & 3) != 0) |
| 297 | A = EXTRACT_LONG(&p[k]); |
| 298 | else |
| 299 | #endif |
| 300 | A = ntohl(*(int32_t *)(p + k)); |
| 301 | continue; |
| 302 | |
| 303 | case BPF_LD|BPF_H|BPF_IND: |
| 304 | k = X + pc->k; |
| 305 | if (X > buflen || pc->k > buflen - X || |
| 306 | sizeof(int16_t) > buflen - k) { |
| 307 | #ifdef _KERNEL |
| 308 | int merr; |
| 309 | |
| 310 | if (buflen != 0) |
| 311 | return 0; |
| 312 | A = m_xhalf((struct mbuf *)p, k, &merr); |
| 313 | if (merr != 0) |
| 314 | return 0; |
| 315 | continue; |
| 316 | #else |
| 317 | return 0; |
| 318 | #endif |
| 319 | } |
| 320 | A = EXTRACT_SHORT(&p[k]); |
| 321 | continue; |
| 322 | |
| 323 | case BPF_LD|BPF_B|BPF_IND: |
| 324 | k = X + pc->k; |
| 325 | if (pc->k >= buflen || X >= buflen - pc->k) { |
| 326 | #ifdef _KERNEL |
| 327 | struct mbuf *m; |
| 328 | |
| 329 | if (buflen != 0) |
| 330 | return 0; |
| 331 | m = (struct mbuf *)p; |
| 332 | MINDEX(m, k); |
| 333 | A = mtod(m, u_char *)[k]; |
| 334 | continue; |
| 335 | #else |
| 336 | return 0; |
| 337 | #endif |
| 338 | } |
| 339 | A = p[k]; |
| 340 | continue; |
| 341 | |
| 342 | case BPF_LDX|BPF_MSH|BPF_B: |
| 343 | k = pc->k; |
| 344 | if (k >= buflen) { |
| 345 | #ifdef _KERNEL |
| 346 | struct mbuf *m; |
| 347 | |
| 348 | if (buflen != 0) |
| 349 | return 0; |
| 350 | m = (struct mbuf *)p; |
| 351 | MINDEX(m, k); |
| 352 | X = (mtod(m, char *)[k] & 0xf) << 2; |
| 353 | continue; |
| 354 | #else |
| 355 | return 0; |
| 356 | #endif |
| 357 | } |
| 358 | X = (p[pc->k] & 0xf) << 2; |
| 359 | continue; |
| 360 | |
| 361 | case BPF_LD|BPF_IMM: |
| 362 | A = pc->k; |
| 363 | continue; |
| 364 | |
| 365 | case BPF_LDX|BPF_IMM: |
| 366 | X = pc->k; |
| 367 | continue; |
| 368 | |
| 369 | case BPF_LD|BPF_MEM: |
| 370 | A = mem[pc->k]; |
| 371 | continue; |
| 372 | |
| 373 | case BPF_LDX|BPF_MEM: |
| 374 | X = mem[pc->k]; |
| 375 | continue; |
| 376 | |
| 377 | case BPF_ST: |
| 378 | mem[pc->k] = A; |
| 379 | continue; |
| 380 | |
| 381 | case BPF_STX: |
| 382 | mem[pc->k] = X; |
| 383 | continue; |
| 384 | |
| 385 | case BPF_JMP|BPF_JA: |
| 386 | pc += pc->k; |
| 387 | continue; |
| 388 | |
| 389 | case BPF_JMP|BPF_JGT|BPF_K: |
| 390 | pc += (A > pc->k) ? pc->jt : pc->jf; |
| 391 | continue; |
| 392 | |
| 393 | case BPF_JMP|BPF_JGE|BPF_K: |
| 394 | pc += (A >= pc->k) ? pc->jt : pc->jf; |
| 395 | continue; |
| 396 | |
| 397 | case BPF_JMP|BPF_JEQ|BPF_K: |
| 398 | pc += (A == pc->k) ? pc->jt : pc->jf; |
| 399 | continue; |
| 400 | |
| 401 | case BPF_JMP|BPF_JSET|BPF_K: |
| 402 | pc += (A & pc->k) ? pc->jt : pc->jf; |
| 403 | continue; |
| 404 | |
| 405 | case BPF_JMP|BPF_JGT|BPF_X: |
| 406 | pc += (A > X) ? pc->jt : pc->jf; |
| 407 | continue; |
| 408 | |
| 409 | case BPF_JMP|BPF_JGE|BPF_X: |
| 410 | pc += (A >= X) ? pc->jt : pc->jf; |
| 411 | continue; |
| 412 | |
| 413 | case BPF_JMP|BPF_JEQ|BPF_X: |
| 414 | pc += (A == X) ? pc->jt : pc->jf; |
| 415 | continue; |
| 416 | |
| 417 | case BPF_JMP|BPF_JSET|BPF_X: |
| 418 | pc += (A & X) ? pc->jt : pc->jf; |
| 419 | continue; |
| 420 | |
| 421 | case BPF_ALU|BPF_ADD|BPF_X: |
| 422 | A += X; |
| 423 | continue; |
| 424 | |
| 425 | case BPF_ALU|BPF_SUB|BPF_X: |
| 426 | A -= X; |
| 427 | continue; |
| 428 | |
| 429 | case BPF_ALU|BPF_MUL|BPF_X: |
| 430 | A *= X; |
| 431 | continue; |
| 432 | |
| 433 | case BPF_ALU|BPF_DIV|BPF_X: |
| 434 | if (X == 0) |
| 435 | return 0; |
| 436 | A /= X; |
| 437 | continue; |
| 438 | |
| 439 | case BPF_ALU|BPF_AND|BPF_X: |
| 440 | A &= X; |
| 441 | continue; |
| 442 | |
| 443 | case BPF_ALU|BPF_OR|BPF_X: |
| 444 | A |= X; |
| 445 | continue; |
| 446 | |
| 447 | case BPF_ALU|BPF_LSH|BPF_X: |
| 448 | A <<= X; |
| 449 | continue; |
| 450 | |
| 451 | case BPF_ALU|BPF_RSH|BPF_X: |
| 452 | A >>= X; |
| 453 | continue; |
| 454 | |
| 455 | case BPF_ALU|BPF_ADD|BPF_K: |
| 456 | A += pc->k; |
| 457 | continue; |
| 458 | |
| 459 | case BPF_ALU|BPF_SUB|BPF_K: |
| 460 | A -= pc->k; |
| 461 | continue; |
| 462 | |
| 463 | case BPF_ALU|BPF_MUL|BPF_K: |
| 464 | A *= pc->k; |
| 465 | continue; |
| 466 | |
| 467 | case BPF_ALU|BPF_DIV|BPF_K: |
| 468 | A /= pc->k; |
| 469 | continue; |
| 470 | |
| 471 | case BPF_ALU|BPF_AND|BPF_K: |
| 472 | A &= pc->k; |
| 473 | continue; |
| 474 | |
| 475 | case BPF_ALU|BPF_OR|BPF_K: |
| 476 | A |= pc->k; |
| 477 | continue; |
| 478 | |
| 479 | case BPF_ALU|BPF_LSH|BPF_K: |
| 480 | A <<= pc->k; |
| 481 | continue; |
| 482 | |
| 483 | case BPF_ALU|BPF_RSH|BPF_K: |
| 484 | A >>= pc->k; |
| 485 | continue; |
| 486 | |
| 487 | case BPF_ALU|BPF_NEG: |
| 488 | A = -A; |
| 489 | continue; |
| 490 | |
| 491 | case BPF_MISC|BPF_TAX: |
| 492 | X = A; |
| 493 | continue; |
| 494 | |
| 495 | case BPF_MISC|BPF_TXA: |
| 496 | A = X; |
| 497 | continue; |
| 498 | } |
| 499 | } |
| 500 | } |
| 501 | |
| 502 | #ifdef _KERNEL |
| 503 | /* |
| 504 | * Return true if the 'fcode' is a valid filter program. |
| 505 | * The constraints are that each jump be forward and to a valid |
| 506 | * code, that memory accesses are within valid ranges (to the |
| 507 | * extent that this can be checked statically; loads of packet |
| 508 | * data have to be, and are, also checked at run time), and that |
| 509 | * the code terminates with either an accept or reject. |
| 510 | * |
| 511 | * The kernel needs to be able to verify an application's filter code. |
| 512 | * Otherwise, a bogus program could easily crash the system. |
| 513 | */ |
| 514 | int |
| 515 | bpf_validate(const struct bpf_insn *f, int len) |
| 516 | { |
| 517 | u_int i, from; |
| 518 | const struct bpf_insn *p; |
| 519 | |
| 520 | if (len < 1 || len > BPF_MAXINSNS) |
| 521 | return 0; |
| 522 | |
| 523 | for (i = 0; i < len; ++i) { |
| 524 | p = &f[i]; |
| 525 | switch (BPF_CLASS(p->code)) { |
| 526 | /* |
| 527 | * Check that memory operations use valid addresses. |
| 528 | */ |
| 529 | case BPF_LD: |
| 530 | case BPF_LDX: |
| 531 | switch (BPF_MODE(p->code)) { |
| 532 | case BPF_IMM: |
| 533 | break; |
| 534 | case BPF_ABS: |
| 535 | case BPF_IND: |
| 536 | case BPF_MSH: |
| 537 | /* |
| 538 | * More strict check with actual packet length |
| 539 | * is done runtime. |
| 540 | */ |
| 541 | if (p->k >= bpf_maxbufsize) |
| 542 | return 0; |
| 543 | break; |
| 544 | case BPF_MEM: |
| 545 | if (p->k >= BPF_MEMWORDS) |
| 546 | return 0; |
| 547 | break; |
| 548 | case BPF_LEN: |
| 549 | break; |
| 550 | default: |
| 551 | return 0; |
| 552 | } |
| 553 | break; |
| 554 | case BPF_ST: |
| 555 | case BPF_STX: |
| 556 | if (p->k >= BPF_MEMWORDS) |
| 557 | return 0; |
| 558 | break; |
| 559 | case BPF_ALU: |
| 560 | switch (BPF_OP(p->code)) { |
| 561 | case BPF_ADD: |
| 562 | case BPF_SUB: |
| 563 | case BPF_MUL: |
| 564 | case BPF_OR: |
| 565 | case BPF_AND: |
| 566 | case BPF_LSH: |
| 567 | case BPF_RSH: |
| 568 | case BPF_NEG: |
| 569 | break; |
| 570 | case BPF_DIV: |
| 571 | /* |
| 572 | * Check for constant division by 0. |
| 573 | */ |
| 574 | if (BPF_SRC(p->code) == BPF_K && p->k == 0) |
| 575 | return 0; |
| 576 | break; |
| 577 | default: |
| 578 | return 0; |
| 579 | } |
| 580 | break; |
| 581 | case BPF_JMP: |
| 582 | /* |
| 583 | * Check that jumps are within the code block, |
| 584 | * and that unconditional branches don't go |
| 585 | * backwards as a result of an overflow. |
| 586 | * Unconditional branches have a 32-bit offset, |
| 587 | * so they could overflow; we check to make |
| 588 | * sure they don't. Conditional branches have |
| 589 | * an 8-bit offset, and the from address is <= |
| 590 | * BPF_MAXINSNS, and we assume that BPF_MAXINSNS |
| 591 | * is sufficiently small that adding 255 to it |
| 592 | * won't overflow. |
| 593 | * |
| 594 | * We know that len is <= BPF_MAXINSNS, and we |
| 595 | * assume that BPF_MAXINSNS is < the maximum size |
| 596 | * of a u_int, so that i + 1 doesn't overflow. |
| 597 | */ |
| 598 | from = i + 1; |
| 599 | switch (BPF_OP(p->code)) { |
| 600 | case BPF_JA: |
| 601 | if (from + p->k < from || from + p->k >= len) |
| 602 | return 0; |
| 603 | break; |
| 604 | case BPF_JEQ: |
| 605 | case BPF_JGT: |
| 606 | case BPF_JGE: |
| 607 | case BPF_JSET: |
| 608 | if (from + p->jt >= len || from + p->jf >= len) |
| 609 | return 0; |
| 610 | break; |
| 611 | default: |
| 612 | return 0; |
| 613 | } |
| 614 | break; |
| 615 | case BPF_RET: |
| 616 | break; |
| 617 | case BPF_MISC: |
| 618 | break; |
| 619 | default: |
| 620 | return 0; |
| 621 | } |
| 622 | } |
| 623 | return BPF_CLASS(f[len - 1].code) == BPF_RET; |
| 624 | } |
| 625 | #endif |