1 /* $FreeBSD$ */ 2 /* $OpenBSD: ip_ah.c,v 1.63 2001/06/26 06:18:58 angelos Exp $ */ 3 /*- 4 * The authors of this code are John Ioannidis (ji@tla.org), 5 * Angelos D. Keromytis (kermit@csd.uch.gr) and 6 * Niels Provos (provos@physnet.uni-hamburg.de). 7 * 8 * The original version of this code was written by John Ioannidis 9 * for BSD/OS in Athens, Greece, in November 1995. 10 * 11 * Ported to OpenBSD and NetBSD, with additional transforms, in December 1996, 12 * by Angelos D. Keromytis. 13 * 14 * Additional transforms and features in 1997 and 1998 by Angelos D. Keromytis 15 * and Niels Provos. 16 * 17 * Additional features in 1999 by Angelos D. Keromytis and Niklas Hallqvist. 18 * 19 * Copyright (c) 1995, 1996, 1997, 1998, 1999 by John Ioannidis, 20 * Angelos D. Keromytis and Niels Provos. 21 * Copyright (c) 1999 Niklas Hallqvist. 22 * Copyright (c) 2001 Angelos D. Keromytis. 23 * 24 * Permission to use, copy, and modify this software with or without fee 25 * is hereby granted, provided that this entire notice is included in 26 * all copies of any software which is or includes a copy or 27 * modification of this software. 28 * You may use this code under the GNU public license if you so wish. Please 29 * contribute changes back to the authors under this freer than GPL license 30 * so that we may further the use of strong encryption without limitations to 31 * all. 32 * 33 * THIS SOFTWARE IS BEING PROVIDED "AS IS", WITHOUT ANY EXPRESS OR 34 * IMPLIED WARRANTY. IN PARTICULAR, NONE OF THE AUTHORS MAKES ANY 35 * REPRESENTATION OR WARRANTY OF ANY KIND CONCERNING THE 36 * MERCHANTABILITY OF THIS SOFTWARE OR ITS FITNESS FOR ANY PARTICULAR 37 * PURPOSE. 38 */ 39 #include "opt_inet.h" 40 #include "opt_inet6.h" 41 42 #include <sys/param.h> 43 #include <sys/systm.h> 44 #include <sys/mbuf.h> 45 #include <sys/socket.h> 46 #include <sys/syslog.h> 47 #include <sys/kernel.h> 48 #include <sys/sysctl.h> 49 #include <sys/vimage.h> 50 51 #include <net/if.h> 52 53 #include <netinet/in.h> 54 #include <netinet/in_systm.h> 55 #include <netinet/ip.h> 56 #include <netinet/ip_ecn.h> 57 #include <netinet/ip6.h> 58 59 #include <net/route.h> 60 #include <netipsec/ipsec.h> 61 #include <netipsec/ah.h> 62 #include <netipsec/ah_var.h> 63 #include <netipsec/xform.h> 64 65 #ifdef INET6 66 #include <netinet6/ip6_var.h> 67 #include <netipsec/ipsec6.h> 68 #include <netinet6/ip6_ecn.h> 69 #endif 70 71 #include <netipsec/key.h> 72 #include <netipsec/key_debug.h> 73 74 #include <opencrypto/cryptodev.h> 75 76 /* 77 * Return header size in bytes. The old protocol did not support 78 * the replay counter; the new protocol always includes the counter. 79 */ 80 #define HDRSIZE(sav) \ 81 (((sav)->flags & SADB_X_EXT_OLD) ? \ 82 sizeof (struct ah) : sizeof (struct ah) + sizeof (u_int32_t)) 83 /* 84 * Return authenticator size in bytes. The old protocol is known 85 * to use a fixed 16-byte authenticator. The new algorithm use 12-byte 86 * authenticator. 87 */ 88 #define AUTHSIZE(sav) \ 89 ((sav->flags & SADB_X_EXT_OLD) ? 16 : AH_HMAC_HASHLEN) 90 91 int ah_enable = 1; /* control flow of packets with AH */ 92 int ah_cleartos = 1; /* clear ip_tos when doing AH calc */ 93 struct ahstat ahstat; 94 95 SYSCTL_DECL(_net_inet_ah); 96 SYSCTL_V_INT(V_NET, vnet_ipsec, _net_inet_ah, OID_AUTO, 97 ah_enable, CTLFLAG_RW, ah_enable, 0, ""); 98 SYSCTL_V_INT(V_NET, vnet_ipsec, _net_inet_ah, OID_AUTO, 99 ah_cleartos, CTLFLAG_RW, ah_cleartos, 0, ""); 100 SYSCTL_V_STRUCT(V_NET, vnet_ipsec, _net_inet_ah, IPSECCTL_STATS, 101 stats, CTLFLAG_RD, ahstat, ahstat, ""); 102 103 static unsigned char ipseczeroes[256]; /* larger than an ip6 extension hdr */ 104 105 static int ah_input_cb(struct cryptop*); 106 static int ah_output_cb(struct cryptop*); 107 108 /* 109 * NB: this is public for use by the PF_KEY support. 110 */ 111 struct auth_hash * 112 ah_algorithm_lookup(int alg) 113 { 114 if (alg > SADB_AALG_MAX) 115 return NULL; 116 switch (alg) { 117 case SADB_X_AALG_NULL: 118 return &auth_hash_null; 119 case SADB_AALG_MD5HMAC: 120 return &auth_hash_hmac_md5; 121 case SADB_AALG_SHA1HMAC: 122 return &auth_hash_hmac_sha1; 123 case SADB_X_AALG_RIPEMD160HMAC: 124 return &auth_hash_hmac_ripemd_160; 125 case SADB_X_AALG_MD5: 126 return &auth_hash_key_md5; 127 case SADB_X_AALG_SHA: 128 return &auth_hash_key_sha1; 129 case SADB_X_AALG_SHA2_256: 130 return &auth_hash_hmac_sha2_256; 131 case SADB_X_AALG_SHA2_384: 132 return &auth_hash_hmac_sha2_384; 133 case SADB_X_AALG_SHA2_512: 134 return &auth_hash_hmac_sha2_512; 135 } 136 return NULL; 137 } 138 139 size_t 140 ah_hdrsiz(struct secasvar *sav) 141 { 142 size_t size; 143 144 if (sav != NULL) { 145 int authsize; 146 IPSEC_ASSERT(sav->tdb_authalgxform != NULL, ("null xform")); 147 /*XXX not right for null algorithm--does it matter??*/ 148 authsize = AUTHSIZE(sav); 149 size = roundup(authsize, sizeof (u_int32_t)) + HDRSIZE(sav); 150 } else { 151 /* default guess */ 152 size = sizeof (struct ah) + sizeof (u_int32_t) + 16; 153 } 154 return size; 155 } 156 157 /* 158 * NB: public for use by esp_init. 159 */ 160 int 161 ah_init0(struct secasvar *sav, struct xformsw *xsp, struct cryptoini *cria) 162 { 163 INIT_VNET_IPSEC(curvnet); 164 struct auth_hash *thash; 165 int keylen; 166 167 thash = ah_algorithm_lookup(sav->alg_auth); 168 if (thash == NULL) { 169 DPRINTF(("%s: unsupported authentication algorithm %u\n", 170 __func__, sav->alg_auth)); 171 return EINVAL; 172 } 173 /* 174 * Verify the replay state block allocation is consistent with 175 * the protocol type. We check here so we can make assumptions 176 * later during protocol processing. 177 */ 178 /* NB: replay state is setup elsewhere (sigh) */ 179 if (((sav->flags&SADB_X_EXT_OLD) == 0) ^ (sav->replay != NULL)) { 180 DPRINTF(("%s: replay state block inconsistency, " 181 "%s algorithm %s replay state\n", __func__, 182 (sav->flags & SADB_X_EXT_OLD) ? "old" : "new", 183 sav->replay == NULL ? "without" : "with")); 184 return EINVAL; 185 } 186 if (sav->key_auth == NULL) { 187 DPRINTF(("%s: no authentication key for %s algorithm\n", 188 __func__, thash->name)); 189 return EINVAL; 190 } 191 keylen = _KEYLEN(sav->key_auth); 192 if (keylen != thash->keysize && thash->keysize != 0) { 193 DPRINTF(("%s: invalid keylength %d, algorithm %s requires " 194 "keysize %d\n", __func__, 195 keylen, thash->name, thash->keysize)); 196 return EINVAL; 197 } 198 199 sav->tdb_xform = xsp; 200 sav->tdb_authalgxform = thash; 201 202 /* Initialize crypto session. */ 203 bzero(cria, sizeof (*cria)); 204 cria->cri_alg = sav->tdb_authalgxform->type; 205 cria->cri_klen = _KEYBITS(sav->key_auth); 206 cria->cri_key = sav->key_auth->key_data; 207 cria->cri_mlen = AUTHSIZE(sav); 208 209 return 0; 210 } 211 212 /* 213 * ah_init() is called when an SPI is being set up. 214 */ 215 static int 216 ah_init(struct secasvar *sav, struct xformsw *xsp) 217 { 218 INIT_VNET_IPSEC(curvnet); 219 struct cryptoini cria; 220 int error; 221 222 error = ah_init0(sav, xsp, &cria); 223 return error ? error : 224 crypto_newsession(&sav->tdb_cryptoid, &cria, V_crypto_support); 225 } 226 227 /* 228 * Paranoia. 229 * 230 * NB: public for use by esp_zeroize (XXX). 231 */ 232 int 233 ah_zeroize(struct secasvar *sav) 234 { 235 int err; 236 237 if (sav->key_auth) 238 bzero(sav->key_auth->key_data, _KEYLEN(sav->key_auth)); 239 240 err = crypto_freesession(sav->tdb_cryptoid); 241 sav->tdb_cryptoid = 0; 242 sav->tdb_authalgxform = NULL; 243 sav->tdb_xform = NULL; 244 return err; 245 } 246 247 /* 248 * Massage IPv4/IPv6 headers for AH processing. 249 */ 250 static int 251 ah_massage_headers(struct mbuf **m0, int proto, int skip, int alg, int out) 252 { 253 INIT_VNET_IPSEC(curvnet); 254 struct mbuf *m = *m0; 255 unsigned char *ptr; 256 int off, count; 257 258 #ifdef INET 259 struct ip *ip; 260 #endif /* INET */ 261 262 #ifdef INET6 263 struct ip6_ext *ip6e; 264 struct ip6_hdr ip6; 265 int alloc, len, ad; 266 #endif /* INET6 */ 267 268 switch (proto) { 269 #ifdef INET 270 case AF_INET: 271 /* 272 * This is the least painful way of dealing with IPv4 header 273 * and option processing -- just make sure they're in 274 * contiguous memory. 275 */ 276 *m0 = m = m_pullup(m, skip); 277 if (m == NULL) { 278 DPRINTF(("%s: m_pullup failed\n", __func__)); 279 return ENOBUFS; 280 } 281 282 /* Fix the IP header */ 283 ip = mtod(m, struct ip *); 284 if (V_ah_cleartos) 285 ip->ip_tos = 0; 286 ip->ip_ttl = 0; 287 ip->ip_sum = 0; 288 289 /* 290 * On input, fix ip_len which has been byte-swapped 291 * at ip_input(). 292 */ 293 if (!out) { 294 ip->ip_len = htons(ip->ip_len + skip); 295 296 if (alg == CRYPTO_MD5_KPDK || alg == CRYPTO_SHA1_KPDK) 297 ip->ip_off = htons(ip->ip_off & IP_DF); 298 else 299 ip->ip_off = 0; 300 } else { 301 if (alg == CRYPTO_MD5_KPDK || alg == CRYPTO_SHA1_KPDK) 302 ip->ip_off = htons(ntohs(ip->ip_off) & IP_DF); 303 else 304 ip->ip_off = 0; 305 } 306 307 ptr = mtod(m, unsigned char *) + sizeof(struct ip); 308 309 /* IPv4 option processing */ 310 for (off = sizeof(struct ip); off < skip;) { 311 if (ptr[off] == IPOPT_EOL || ptr[off] == IPOPT_NOP || 312 off + 1 < skip) 313 ; 314 else { 315 DPRINTF(("%s: illegal IPv4 option length for " 316 "option %d\n", __func__, ptr[off])); 317 318 m_freem(m); 319 return EINVAL; 320 } 321 322 switch (ptr[off]) { 323 case IPOPT_EOL: 324 off = skip; /* End the loop. */ 325 break; 326 327 case IPOPT_NOP: 328 off++; 329 break; 330 331 case IPOPT_SECURITY: /* 0x82 */ 332 case 0x85: /* Extended security. */ 333 case 0x86: /* Commercial security. */ 334 case 0x94: /* Router alert */ 335 case 0x95: /* RFC1770 */ 336 /* Sanity check for option length. */ 337 if (ptr[off + 1] < 2) { 338 DPRINTF(("%s: illegal IPv4 option " 339 "length for option %d\n", 340 __func__, ptr[off])); 341 342 m_freem(m); 343 return EINVAL; 344 } 345 346 off += ptr[off + 1]; 347 break; 348 349 case IPOPT_LSRR: 350 case IPOPT_SSRR: 351 /* Sanity check for option length. */ 352 if (ptr[off + 1] < 2) { 353 DPRINTF(("%s: illegal IPv4 option " 354 "length for option %d\n", 355 __func__, ptr[off])); 356 357 m_freem(m); 358 return EINVAL; 359 } 360 361 /* 362 * On output, if we have either of the 363 * source routing options, we should 364 * swap the destination address of the 365 * IP header with the last address 366 * specified in the option, as that is 367 * what the destination's IP header 368 * will look like. 369 */ 370 if (out) 371 bcopy(ptr + off + ptr[off + 1] - 372 sizeof(struct in_addr), 373 &(ip->ip_dst), sizeof(struct in_addr)); 374 375 /* Fall through */ 376 default: 377 /* Sanity check for option length. */ 378 if (ptr[off + 1] < 2) { 379 DPRINTF(("%s: illegal IPv4 option " 380 "length for option %d\n", 381 __func__, ptr[off])); 382 m_freem(m); 383 return EINVAL; 384 } 385 386 /* Zeroize all other options. */ 387 count = ptr[off + 1]; 388 bcopy(ipseczeroes, ptr, count); 389 off += count; 390 break; 391 } 392 393 /* Sanity check. */ 394 if (off > skip) { 395 DPRINTF(("%s: malformed IPv4 options header\n", 396 __func__)); 397 398 m_freem(m); 399 return EINVAL; 400 } 401 } 402 403 break; 404 #endif /* INET */ 405 406 #ifdef INET6 407 case AF_INET6: /* Ugly... */ 408 /* Copy and "cook" the IPv6 header. */ 409 m_copydata(m, 0, sizeof(ip6), (caddr_t) &ip6); 410 411 /* We don't do IPv6 Jumbograms. */ 412 if (ip6.ip6_plen == 0) { 413 DPRINTF(("%s: unsupported IPv6 jumbogram\n", __func__)); 414 m_freem(m); 415 return EMSGSIZE; 416 } 417 418 ip6.ip6_flow = 0; 419 ip6.ip6_hlim = 0; 420 ip6.ip6_vfc &= ~IPV6_VERSION_MASK; 421 ip6.ip6_vfc |= IPV6_VERSION; 422 423 /* Scoped address handling. */ 424 if (IN6_IS_SCOPE_LINKLOCAL(&ip6.ip6_src)) 425 ip6.ip6_src.s6_addr16[1] = 0; 426 if (IN6_IS_SCOPE_LINKLOCAL(&ip6.ip6_dst)) 427 ip6.ip6_dst.s6_addr16[1] = 0; 428 429 /* Done with IPv6 header. */ 430 m_copyback(m, 0, sizeof(struct ip6_hdr), (caddr_t) &ip6); 431 432 /* Let's deal with the remaining headers (if any). */ 433 if (skip - sizeof(struct ip6_hdr) > 0) { 434 if (m->m_len <= skip) { 435 ptr = (unsigned char *) malloc( 436 skip - sizeof(struct ip6_hdr), 437 M_XDATA, M_NOWAIT); 438 if (ptr == NULL) { 439 DPRINTF(("%s: failed to allocate memory" 440 "for IPv6 headers\n",__func__)); 441 m_freem(m); 442 return ENOBUFS; 443 } 444 445 /* 446 * Copy all the protocol headers after 447 * the IPv6 header. 448 */ 449 m_copydata(m, sizeof(struct ip6_hdr), 450 skip - sizeof(struct ip6_hdr), ptr); 451 alloc = 1; 452 } else { 453 /* No need to allocate memory. */ 454 ptr = mtod(m, unsigned char *) + 455 sizeof(struct ip6_hdr); 456 alloc = 0; 457 } 458 } else 459 break; 460 461 off = ip6.ip6_nxt & 0xff; /* Next header type. */ 462 463 for (len = 0; len < skip - sizeof(struct ip6_hdr);) 464 switch (off) { 465 case IPPROTO_HOPOPTS: 466 case IPPROTO_DSTOPTS: 467 ip6e = (struct ip6_ext *) (ptr + len); 468 469 /* 470 * Process the mutable/immutable 471 * options -- borrows heavily from the 472 * KAME code. 473 */ 474 for (count = len + sizeof(struct ip6_ext); 475 count < len + ((ip6e->ip6e_len + 1) << 3);) { 476 if (ptr[count] == IP6OPT_PAD1) { 477 count++; 478 continue; /* Skip padding. */ 479 } 480 481 /* Sanity check. */ 482 if (count > len + 483 ((ip6e->ip6e_len + 1) << 3)) { 484 m_freem(m); 485 486 /* Free, if we allocated. */ 487 if (alloc) 488 free(ptr, M_XDATA); 489 return EINVAL; 490 } 491 492 ad = ptr[count + 1]; 493 494 /* If mutable option, zeroize. */ 495 if (ptr[count] & IP6OPT_MUTABLE) 496 bcopy(ipseczeroes, ptr + count, 497 ptr[count + 1]); 498 499 count += ad; 500 501 /* Sanity check. */ 502 if (count > 503 skip - sizeof(struct ip6_hdr)) { 504 m_freem(m); 505 506 /* Free, if we allocated. */ 507 if (alloc) 508 free(ptr, M_XDATA); 509 return EINVAL; 510 } 511 } 512 513 /* Advance. */ 514 len += ((ip6e->ip6e_len + 1) << 3); 515 off = ip6e->ip6e_nxt; 516 break; 517 518 case IPPROTO_ROUTING: 519 /* 520 * Always include routing headers in 521 * computation. 522 */ 523 ip6e = (struct ip6_ext *) (ptr + len); 524 len += ((ip6e->ip6e_len + 1) << 3); 525 off = ip6e->ip6e_nxt; 526 break; 527 528 default: 529 DPRINTF(("%s: unexpected IPv6 header type %d", 530 __func__, off)); 531 if (alloc) 532 free(ptr, M_XDATA); 533 m_freem(m); 534 return EINVAL; 535 } 536 537 /* Copyback and free, if we allocated. */ 538 if (alloc) { 539 m_copyback(m, sizeof(struct ip6_hdr), 540 skip - sizeof(struct ip6_hdr), ptr); 541 free(ptr, M_XDATA); 542 } 543 544 break; 545 #endif /* INET6 */ 546 } 547 548 return 0; 549 } 550 551 /* 552 * ah_input() gets called to verify that an input packet 553 * passes authentication. 554 */ 555 static int 556 ah_input(struct mbuf *m, struct secasvar *sav, int skip, int protoff) 557 { 558 INIT_VNET_IPSEC(curvnet); 559 struct auth_hash *ahx; 560 struct tdb_ident *tdbi; 561 struct tdb_crypto *tc; 562 struct m_tag *mtag; 563 struct newah *ah; 564 int hl, rplen, authsize; 565 566 struct cryptodesc *crda; 567 struct cryptop *crp; 568 569 IPSEC_ASSERT(sav != NULL, ("null SA")); 570 IPSEC_ASSERT(sav->key_auth != NULL, ("null authentication key")); 571 IPSEC_ASSERT(sav->tdb_authalgxform != NULL, 572 ("null authentication xform")); 573 574 /* Figure out header size. */ 575 rplen = HDRSIZE(sav); 576 577 /* XXX don't pullup, just copy header */ 578 IP6_EXTHDR_GET(ah, struct newah *, m, skip, rplen); 579 if (ah == NULL) { 580 DPRINTF(("ah_input: cannot pullup header\n")); 581 V_ahstat.ahs_hdrops++; /*XXX*/ 582 m_freem(m); 583 return ENOBUFS; 584 } 585 586 /* Check replay window, if applicable. */ 587 if (sav->replay && !ipsec_chkreplay(ntohl(ah->ah_seq), sav)) { 588 V_ahstat.ahs_replay++; 589 DPRINTF(("%s: packet replay failure: %s\n", __func__, 590 ipsec_logsastr(sav))); 591 m_freem(m); 592 return ENOBUFS; 593 } 594 595 /* Verify AH header length. */ 596 hl = ah->ah_len * sizeof (u_int32_t); 597 ahx = sav->tdb_authalgxform; 598 authsize = AUTHSIZE(sav); 599 if (hl != authsize + rplen - sizeof (struct ah)) { 600 DPRINTF(("%s: bad authenticator length %u (expecting %lu)" 601 " for packet in SA %s/%08lx\n", __func__, 602 hl, (u_long) (authsize + rplen - sizeof (struct ah)), 603 ipsec_address(&sav->sah->saidx.dst), 604 (u_long) ntohl(sav->spi))); 605 V_ahstat.ahs_badauthl++; 606 m_freem(m); 607 return EACCES; 608 } 609 V_ahstat.ahs_ibytes += m->m_pkthdr.len - skip - hl; 610 611 /* Get crypto descriptors. */ 612 crp = crypto_getreq(1); 613 if (crp == NULL) { 614 DPRINTF(("%s: failed to acquire crypto descriptor\n",__func__)); 615 V_ahstat.ahs_crypto++; 616 m_freem(m); 617 return ENOBUFS; 618 } 619 620 crda = crp->crp_desc; 621 IPSEC_ASSERT(crda != NULL, ("null crypto descriptor")); 622 623 crda->crd_skip = 0; 624 crda->crd_len = m->m_pkthdr.len; 625 crda->crd_inject = skip + rplen; 626 627 /* Authentication operation. */ 628 crda->crd_alg = ahx->type; 629 crda->crd_klen = _KEYBITS(sav->key_auth); 630 crda->crd_key = sav->key_auth->key_data; 631 632 /* Find out if we've already done crypto. */ 633 for (mtag = m_tag_find(m, PACKET_TAG_IPSEC_IN_CRYPTO_DONE, NULL); 634 mtag != NULL; 635 mtag = m_tag_find(m, PACKET_TAG_IPSEC_IN_CRYPTO_DONE, mtag)) { 636 tdbi = (struct tdb_ident *) (mtag + 1); 637 if (tdbi->proto == sav->sah->saidx.proto && 638 tdbi->spi == sav->spi && 639 !bcmp(&tdbi->dst, &sav->sah->saidx.dst, 640 sizeof (union sockaddr_union))) 641 break; 642 } 643 644 /* Allocate IPsec-specific opaque crypto info. */ 645 if (mtag == NULL) { 646 tc = (struct tdb_crypto *) malloc(sizeof (struct tdb_crypto) + 647 skip + rplen + authsize, M_XDATA, M_NOWAIT|M_ZERO); 648 } else { 649 /* Hash verification has already been done successfully. */ 650 tc = (struct tdb_crypto *) malloc(sizeof (struct tdb_crypto), 651 M_XDATA, M_NOWAIT|M_ZERO); 652 } 653 if (tc == NULL) { 654 DPRINTF(("%s: failed to allocate tdb_crypto\n", __func__)); 655 V_ahstat.ahs_crypto++; 656 crypto_freereq(crp); 657 m_freem(m); 658 return ENOBUFS; 659 } 660 661 /* Only save information if crypto processing is needed. */ 662 if (mtag == NULL) { 663 int error; 664 665 /* 666 * Save the authenticator, the skipped portion of the packet, 667 * and the AH header. 668 */ 669 m_copydata(m, 0, skip + rplen + authsize, (caddr_t)(tc+1)); 670 671 /* Zeroize the authenticator on the packet. */ 672 m_copyback(m, skip + rplen, authsize, ipseczeroes); 673 674 /* "Massage" the packet headers for crypto processing. */ 675 error = ah_massage_headers(&m, sav->sah->saidx.dst.sa.sa_family, 676 skip, ahx->type, 0); 677 if (error != 0) { 678 /* NB: mbuf is free'd by ah_massage_headers */ 679 V_ahstat.ahs_hdrops++; 680 free(tc, M_XDATA); 681 crypto_freereq(crp); 682 return error; 683 } 684 } 685 686 /* Crypto operation descriptor. */ 687 crp->crp_ilen = m->m_pkthdr.len; /* Total input length. */ 688 crp->crp_flags = CRYPTO_F_IMBUF | CRYPTO_F_CBIFSYNC; 689 crp->crp_buf = (caddr_t) m; 690 crp->crp_callback = ah_input_cb; 691 crp->crp_sid = sav->tdb_cryptoid; 692 crp->crp_opaque = (caddr_t) tc; 693 694 /* These are passed as-is to the callback. */ 695 tc->tc_spi = sav->spi; 696 tc->tc_dst = sav->sah->saidx.dst; 697 tc->tc_proto = sav->sah->saidx.proto; 698 tc->tc_nxt = ah->ah_nxt; 699 tc->tc_protoff = protoff; 700 tc->tc_skip = skip; 701 tc->tc_ptr = (caddr_t) mtag; /* Save the mtag we've identified. */ 702 703 if (mtag == NULL) 704 return crypto_dispatch(crp); 705 else 706 return ah_input_cb(crp); 707 } 708 709 #ifdef INET6 710 #define IPSEC_COMMON_INPUT_CB(m, sav, skip, protoff, mtag) do { \ 711 if (saidx->dst.sa.sa_family == AF_INET6) { \ 712 error = ipsec6_common_input_cb(m, sav, skip, protoff, mtag); \ 713 } else { \ 714 error = ipsec4_common_input_cb(m, sav, skip, protoff, mtag); \ 715 } \ 716 } while (0) 717 #else 718 #define IPSEC_COMMON_INPUT_CB(m, sav, skip, protoff, mtag) \ 719 (error = ipsec4_common_input_cb(m, sav, skip, protoff, mtag)) 720 #endif 721 722 /* 723 * AH input callback from the crypto driver. 724 */ 725 static int 726 ah_input_cb(struct cryptop *crp) 727 { 728 INIT_VNET_IPSEC(curvnet); 729 int rplen, error, skip, protoff; 730 unsigned char calc[AH_ALEN_MAX]; 731 struct mbuf *m; 732 struct cryptodesc *crd; 733 struct auth_hash *ahx; 734 struct tdb_crypto *tc; 735 struct m_tag *mtag; 736 struct secasvar *sav; 737 struct secasindex *saidx; 738 u_int8_t nxt; 739 caddr_t ptr; 740 int authsize; 741 742 crd = crp->crp_desc; 743 744 tc = (struct tdb_crypto *) crp->crp_opaque; 745 IPSEC_ASSERT(tc != NULL, ("null opaque crypto data area!")); 746 skip = tc->tc_skip; 747 nxt = tc->tc_nxt; 748 protoff = tc->tc_protoff; 749 mtag = (struct m_tag *) tc->tc_ptr; 750 m = (struct mbuf *) crp->crp_buf; 751 752 sav = KEY_ALLOCSA(&tc->tc_dst, tc->tc_proto, tc->tc_spi); 753 if (sav == NULL) { 754 V_ahstat.ahs_notdb++; 755 DPRINTF(("%s: SA expired while in crypto\n", __func__)); 756 error = ENOBUFS; /*XXX*/ 757 goto bad; 758 } 759 760 saidx = &sav->sah->saidx; 761 IPSEC_ASSERT(saidx->dst.sa.sa_family == AF_INET || 762 saidx->dst.sa.sa_family == AF_INET6, 763 ("unexpected protocol family %u", saidx->dst.sa.sa_family)); 764 765 ahx = (struct auth_hash *) sav->tdb_authalgxform; 766 767 /* Check for crypto errors. */ 768 if (crp->crp_etype) { 769 if (sav->tdb_cryptoid != 0) 770 sav->tdb_cryptoid = crp->crp_sid; 771 772 if (crp->crp_etype == EAGAIN) { 773 error = crypto_dispatch(crp); 774 return error; 775 } 776 777 V_ahstat.ahs_noxform++; 778 DPRINTF(("%s: crypto error %d\n", __func__, crp->crp_etype)); 779 error = crp->crp_etype; 780 goto bad; 781 } else { 782 V_ahstat.ahs_hist[sav->alg_auth]++; 783 crypto_freereq(crp); /* No longer needed. */ 784 crp = NULL; 785 } 786 787 /* Shouldn't happen... */ 788 if (m == NULL) { 789 V_ahstat.ahs_crypto++; 790 DPRINTF(("%s: bogus returned buffer from crypto\n", __func__)); 791 error = EINVAL; 792 goto bad; 793 } 794 795 /* Figure out header size. */ 796 rplen = HDRSIZE(sav); 797 authsize = AUTHSIZE(sav); 798 799 /* Copy authenticator off the packet. */ 800 m_copydata(m, skip + rplen, authsize, calc); 801 802 /* 803 * If we have an mtag, we don't need to verify the authenticator -- 804 * it has been verified by an IPsec-aware NIC. 805 */ 806 if (mtag == NULL) { 807 ptr = (caddr_t) (tc + 1); 808 809 /* Verify authenticator. */ 810 if (bcmp(ptr + skip + rplen, calc, authsize)) { 811 DPRINTF(("%s: authentication hash mismatch for packet " 812 "in SA %s/%08lx\n", __func__, 813 ipsec_address(&saidx->dst), 814 (u_long) ntohl(sav->spi))); 815 V_ahstat.ahs_badauth++; 816 error = EACCES; 817 goto bad; 818 } 819 820 /* Fix the Next Protocol field. */ 821 ((u_int8_t *) ptr)[protoff] = nxt; 822 823 /* Copyback the saved (uncooked) network headers. */ 824 m_copyback(m, 0, skip, ptr); 825 } else { 826 /* Fix the Next Protocol field. */ 827 m_copyback(m, protoff, sizeof(u_int8_t), &nxt); 828 } 829 830 free(tc, M_XDATA), tc = NULL; /* No longer needed */ 831 832 /* 833 * Header is now authenticated. 834 */ 835 m->m_flags |= M_AUTHIPHDR|M_AUTHIPDGM; 836 837 /* 838 * Update replay sequence number, if appropriate. 839 */ 840 if (sav->replay) { 841 u_int32_t seq; 842 843 m_copydata(m, skip + offsetof(struct newah, ah_seq), 844 sizeof (seq), (caddr_t) &seq); 845 if (ipsec_updatereplay(ntohl(seq), sav)) { 846 V_ahstat.ahs_replay++; 847 error = ENOBUFS; /*XXX as above*/ 848 goto bad; 849 } 850 } 851 852 /* 853 * Remove the AH header and authenticator from the mbuf. 854 */ 855 error = m_striphdr(m, skip, rplen + authsize); 856 if (error) { 857 DPRINTF(("%s: mangled mbuf chain for SA %s/%08lx\n", __func__, 858 ipsec_address(&saidx->dst), (u_long) ntohl(sav->spi))); 859 860 V_ahstat.ahs_hdrops++; 861 goto bad; 862 } 863 864 IPSEC_COMMON_INPUT_CB(m, sav, skip, protoff, mtag); 865 866 KEY_FREESAV(&sav); 867 return error; 868 bad: 869 if (sav) 870 KEY_FREESAV(&sav); 871 if (m != NULL) 872 m_freem(m); 873 if (tc != NULL) 874 free(tc, M_XDATA); 875 if (crp != NULL) 876 crypto_freereq(crp); 877 return error; 878 } 879 880 /* 881 * AH output routine, called by ipsec[46]_process_packet(). 882 */ 883 static int 884 ah_output( 885 struct mbuf *m, 886 struct ipsecrequest *isr, 887 struct mbuf **mp, 888 int skip, 889 int protoff) 890 { 891 INIT_VNET_IPSEC(curvnet); 892 struct secasvar *sav; 893 struct auth_hash *ahx; 894 struct cryptodesc *crda; 895 struct tdb_crypto *tc; 896 struct mbuf *mi; 897 struct cryptop *crp; 898 u_int16_t iplen; 899 int error, rplen, authsize, maxpacketsize, roff; 900 u_int8_t prot; 901 struct newah *ah; 902 903 sav = isr->sav; 904 IPSEC_ASSERT(sav != NULL, ("null SA")); 905 ahx = sav->tdb_authalgxform; 906 IPSEC_ASSERT(ahx != NULL, ("null authentication xform")); 907 908 V_ahstat.ahs_output++; 909 910 /* Figure out header size. */ 911 rplen = HDRSIZE(sav); 912 913 /* Check for maximum packet size violations. */ 914 switch (sav->sah->saidx.dst.sa.sa_family) { 915 #ifdef INET 916 case AF_INET: 917 maxpacketsize = IP_MAXPACKET; 918 break; 919 #endif /* INET */ 920 #ifdef INET6 921 case AF_INET6: 922 maxpacketsize = IPV6_MAXPACKET; 923 break; 924 #endif /* INET6 */ 925 default: 926 DPRINTF(("%s: unknown/unsupported protocol family %u, " 927 "SA %s/%08lx\n", __func__, 928 sav->sah->saidx.dst.sa.sa_family, 929 ipsec_address(&sav->sah->saidx.dst), 930 (u_long) ntohl(sav->spi))); 931 V_ahstat.ahs_nopf++; 932 error = EPFNOSUPPORT; 933 goto bad; 934 } 935 authsize = AUTHSIZE(sav); 936 if (rplen + authsize + m->m_pkthdr.len > maxpacketsize) { 937 DPRINTF(("%s: packet in SA %s/%08lx got too big " 938 "(len %u, max len %u)\n", __func__, 939 ipsec_address(&sav->sah->saidx.dst), 940 (u_long) ntohl(sav->spi), 941 rplen + authsize + m->m_pkthdr.len, maxpacketsize)); 942 V_ahstat.ahs_toobig++; 943 error = EMSGSIZE; 944 goto bad; 945 } 946 947 /* Update the counters. */ 948 V_ahstat.ahs_obytes += m->m_pkthdr.len - skip; 949 950 m = m_unshare(m, M_NOWAIT); 951 if (m == NULL) { 952 DPRINTF(("%s: cannot clone mbuf chain, SA %s/%08lx\n", __func__, 953 ipsec_address(&sav->sah->saidx.dst), 954 (u_long) ntohl(sav->spi))); 955 V_ahstat.ahs_hdrops++; 956 error = ENOBUFS; 957 goto bad; 958 } 959 960 /* Inject AH header. */ 961 mi = m_makespace(m, skip, rplen + authsize, &roff); 962 if (mi == NULL) { 963 DPRINTF(("%s: failed to inject %u byte AH header for SA " 964 "%s/%08lx\n", __func__, 965 rplen + authsize, 966 ipsec_address(&sav->sah->saidx.dst), 967 (u_long) ntohl(sav->spi))); 968 V_ahstat.ahs_hdrops++; /*XXX differs from openbsd */ 969 error = ENOBUFS; 970 goto bad; 971 } 972 973 /* 974 * The AH header is guaranteed by m_makespace() to be in 975 * contiguous memory, at roff bytes offset into the returned mbuf. 976 */ 977 ah = (struct newah *)(mtod(mi, caddr_t) + roff); 978 979 /* Initialize the AH header. */ 980 m_copydata(m, protoff, sizeof(u_int8_t), (caddr_t) &ah->ah_nxt); 981 ah->ah_len = (rplen + authsize - sizeof(struct ah)) / sizeof(u_int32_t); 982 ah->ah_reserve = 0; 983 ah->ah_spi = sav->spi; 984 985 /* Zeroize authenticator. */ 986 m_copyback(m, skip + rplen, authsize, ipseczeroes); 987 988 /* Insert packet replay counter, as requested. */ 989 if (sav->replay) { 990 if (sav->replay->count == ~0 && 991 (sav->flags & SADB_X_EXT_CYCSEQ) == 0) { 992 DPRINTF(("%s: replay counter wrapped for SA %s/%08lx\n", 993 __func__, 994 ipsec_address(&sav->sah->saidx.dst), 995 (u_long) ntohl(sav->spi))); 996 V_ahstat.ahs_wrap++; 997 error = EINVAL; 998 goto bad; 999 } 1000 #ifdef REGRESSION 1001 /* Emulate replay attack when ipsec_replay is TRUE. */ 1002 if (!V_ipsec_replay) 1003 #endif 1004 sav->replay->count++; 1005 ah->ah_seq = htonl(sav->replay->count); 1006 } 1007 1008 /* Get crypto descriptors. */ 1009 crp = crypto_getreq(1); 1010 if (crp == NULL) { 1011 DPRINTF(("%s: failed to acquire crypto descriptors\n", 1012 __func__)); 1013 V_ahstat.ahs_crypto++; 1014 error = ENOBUFS; 1015 goto bad; 1016 } 1017 1018 crda = crp->crp_desc; 1019 1020 crda->crd_skip = 0; 1021 crda->crd_inject = skip + rplen; 1022 crda->crd_len = m->m_pkthdr.len; 1023 1024 /* Authentication operation. */ 1025 crda->crd_alg = ahx->type; 1026 crda->crd_key = sav->key_auth->key_data; 1027 crda->crd_klen = _KEYBITS(sav->key_auth); 1028 1029 /* Allocate IPsec-specific opaque crypto info. */ 1030 tc = (struct tdb_crypto *) malloc( 1031 sizeof(struct tdb_crypto) + skip, M_XDATA, M_NOWAIT|M_ZERO); 1032 if (tc == NULL) { 1033 crypto_freereq(crp); 1034 DPRINTF(("%s: failed to allocate tdb_crypto\n", __func__)); 1035 V_ahstat.ahs_crypto++; 1036 error = ENOBUFS; 1037 goto bad; 1038 } 1039 1040 /* Save the skipped portion of the packet. */ 1041 m_copydata(m, 0, skip, (caddr_t) (tc + 1)); 1042 1043 /* 1044 * Fix IP header length on the header used for 1045 * authentication. We don't need to fix the original 1046 * header length as it will be fixed by our caller. 1047 */ 1048 switch (sav->sah->saidx.dst.sa.sa_family) { 1049 #ifdef INET 1050 case AF_INET: 1051 bcopy(((caddr_t)(tc + 1)) + 1052 offsetof(struct ip, ip_len), 1053 (caddr_t) &iplen, sizeof(u_int16_t)); 1054 iplen = htons(ntohs(iplen) + rplen + authsize); 1055 m_copyback(m, offsetof(struct ip, ip_len), 1056 sizeof(u_int16_t), (caddr_t) &iplen); 1057 break; 1058 #endif /* INET */ 1059 1060 #ifdef INET6 1061 case AF_INET6: 1062 bcopy(((caddr_t)(tc + 1)) + 1063 offsetof(struct ip6_hdr, ip6_plen), 1064 (caddr_t) &iplen, sizeof(u_int16_t)); 1065 iplen = htons(ntohs(iplen) + rplen + authsize); 1066 m_copyback(m, offsetof(struct ip6_hdr, ip6_plen), 1067 sizeof(u_int16_t), (caddr_t) &iplen); 1068 break; 1069 #endif /* INET6 */ 1070 } 1071 1072 /* Fix the Next Header field in saved header. */ 1073 ((u_int8_t *) (tc + 1))[protoff] = IPPROTO_AH; 1074 1075 /* Update the Next Protocol field in the IP header. */ 1076 prot = IPPROTO_AH; 1077 m_copyback(m, protoff, sizeof(u_int8_t), (caddr_t) &prot); 1078 1079 /* "Massage" the packet headers for crypto processing. */ 1080 error = ah_massage_headers(&m, sav->sah->saidx.dst.sa.sa_family, 1081 skip, ahx->type, 1); 1082 if (error != 0) { 1083 m = NULL; /* mbuf was free'd by ah_massage_headers. */ 1084 free(tc, M_XDATA); 1085 crypto_freereq(crp); 1086 goto bad; 1087 } 1088 1089 /* Crypto operation descriptor. */ 1090 crp->crp_ilen = m->m_pkthdr.len; /* Total input length. */ 1091 crp->crp_flags = CRYPTO_F_IMBUF | CRYPTO_F_CBIFSYNC; 1092 crp->crp_buf = (caddr_t) m; 1093 crp->crp_callback = ah_output_cb; 1094 crp->crp_sid = sav->tdb_cryptoid; 1095 crp->crp_opaque = (caddr_t) tc; 1096 1097 /* These are passed as-is to the callback. */ 1098 tc->tc_isr = isr; 1099 tc->tc_spi = sav->spi; 1100 tc->tc_dst = sav->sah->saidx.dst; 1101 tc->tc_proto = sav->sah->saidx.proto; 1102 tc->tc_skip = skip; 1103 tc->tc_protoff = protoff; 1104 1105 return crypto_dispatch(crp); 1106 bad: 1107 if (m) 1108 m_freem(m); 1109 return (error); 1110 } 1111 1112 /* 1113 * AH output callback from the crypto driver. 1114 */ 1115 static int 1116 ah_output_cb(struct cryptop *crp) 1117 { 1118 INIT_VNET_IPSEC(curvnet); 1119 int skip, protoff, error; 1120 struct tdb_crypto *tc; 1121 struct ipsecrequest *isr; 1122 struct secasvar *sav; 1123 struct mbuf *m; 1124 caddr_t ptr; 1125 int err; 1126 1127 tc = (struct tdb_crypto *) crp->crp_opaque; 1128 IPSEC_ASSERT(tc != NULL, ("null opaque data area!")); 1129 skip = tc->tc_skip; 1130 protoff = tc->tc_protoff; 1131 ptr = (caddr_t) (tc + 1); 1132 m = (struct mbuf *) crp->crp_buf; 1133 1134 isr = tc->tc_isr; 1135 IPSECREQUEST_LOCK(isr); 1136 sav = KEY_ALLOCSA(&tc->tc_dst, tc->tc_proto, tc->tc_spi); 1137 if (sav == NULL) { 1138 V_ahstat.ahs_notdb++; 1139 DPRINTF(("%s: SA expired while in crypto\n", __func__)); 1140 error = ENOBUFS; /*XXX*/ 1141 goto bad; 1142 } 1143 IPSEC_ASSERT(isr->sav == sav, ("SA changed\n")); 1144 1145 /* Check for crypto errors. */ 1146 if (crp->crp_etype) { 1147 if (sav->tdb_cryptoid != 0) 1148 sav->tdb_cryptoid = crp->crp_sid; 1149 1150 if (crp->crp_etype == EAGAIN) { 1151 KEY_FREESAV(&sav); 1152 IPSECREQUEST_UNLOCK(isr); 1153 error = crypto_dispatch(crp); 1154 return error; 1155 } 1156 1157 V_ahstat.ahs_noxform++; 1158 DPRINTF(("%s: crypto error %d\n", __func__, crp->crp_etype)); 1159 error = crp->crp_etype; 1160 goto bad; 1161 } 1162 1163 /* Shouldn't happen... */ 1164 if (m == NULL) { 1165 V_ahstat.ahs_crypto++; 1166 DPRINTF(("%s: bogus returned buffer from crypto\n", __func__)); 1167 error = EINVAL; 1168 goto bad; 1169 } 1170 V_ahstat.ahs_hist[sav->alg_auth]++; 1171 1172 /* 1173 * Copy original headers (with the new protocol number) back 1174 * in place. 1175 */ 1176 m_copyback(m, 0, skip, ptr); 1177 1178 /* No longer needed. */ 1179 free(tc, M_XDATA); 1180 crypto_freereq(crp); 1181 1182 #ifdef REGRESSION 1183 /* Emulate man-in-the-middle attack when ipsec_integrity is TRUE. */ 1184 if (V_ipsec_integrity) { 1185 int alen; 1186 1187 /* 1188 * Corrupt HMAC if we want to test integrity verification of 1189 * the other side. 1190 */ 1191 alen = AUTHSIZE(sav); 1192 m_copyback(m, m->m_pkthdr.len - alen, alen, ipseczeroes); 1193 } 1194 #endif 1195 1196 /* NB: m is reclaimed by ipsec_process_done. */ 1197 err = ipsec_process_done(m, isr); 1198 KEY_FREESAV(&sav); 1199 IPSECREQUEST_UNLOCK(isr); 1200 return err; 1201 bad: 1202 if (sav) 1203 KEY_FREESAV(&sav); 1204 IPSECREQUEST_UNLOCK(isr); 1205 if (m) 1206 m_freem(m); 1207 free(tc, M_XDATA); 1208 crypto_freereq(crp); 1209 return error; 1210 } 1211 1212 static struct xformsw ah_xformsw = { 1213 XF_AH, XFT_AUTH, "IPsec AH", 1214 ah_init, ah_zeroize, ah_input, ah_output, 1215 }; 1216 1217 static void 1218 ah_attach(void) 1219 { 1220 xform_register(&ah_xformsw); 1221 } 1222 SYSINIT(ah_xform_init, SI_SUB_PROTO_DOMAIN, SI_ORDER_MIDDLE, ah_attach, NULL); 1223