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 50 #include <net/if.h> 51 #include <net/vnet.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) ah_authsize(sav) 89 90 VNET_DEFINE(int, ah_enable) = 1; /* control flow of packets with AH */ 91 VNET_DEFINE(int, ah_cleartos) = 1; /* clear ip_tos when doing AH calc */ 92 VNET_DEFINE(struct ahstat, ahstat); 93 94 #ifdef INET 95 SYSCTL_DECL(_net_inet_ah); 96 SYSCTL_VNET_INT(_net_inet_ah, OID_AUTO, 97 ah_enable, CTLFLAG_RW, &VNET_NAME(ah_enable), 0, ""); 98 SYSCTL_VNET_INT(_net_inet_ah, OID_AUTO, 99 ah_cleartos, CTLFLAG_RW, &VNET_NAME(ah_cleartos), 0, ""); 100 SYSCTL_VNET_STRUCT(_net_inet_ah, IPSECCTL_STATS, 101 stats, CTLFLAG_RD, &VNET_NAME(ahstat), ahstat, ""); 102 #endif 103 104 static unsigned char ipseczeroes[256]; /* larger than an ip6 extension hdr */ 105 106 static int ah_input_cb(struct cryptop*); 107 static int ah_output_cb(struct cryptop*); 108 109 static int 110 ah_authsize(struct secasvar *sav) 111 { 112 113 IPSEC_ASSERT(sav != NULL, ("%s: sav == NULL", __func__)); 114 115 if (sav->flags & SADB_X_EXT_OLD) 116 return 16; 117 118 switch (sav->alg_auth) { 119 case SADB_X_AALG_SHA2_256: 120 return 16; 121 case SADB_X_AALG_SHA2_384: 122 return 24; 123 case SADB_X_AALG_SHA2_512: 124 return 32; 125 default: 126 return AH_HMAC_HASHLEN; 127 } 128 /* NOTREACHED */ 129 } 130 /* 131 * NB: this is public for use by the PF_KEY support. 132 */ 133 struct auth_hash * 134 ah_algorithm_lookup(int alg) 135 { 136 if (alg > SADB_AALG_MAX) 137 return NULL; 138 switch (alg) { 139 case SADB_X_AALG_NULL: 140 return &auth_hash_null; 141 case SADB_AALG_MD5HMAC: 142 return &auth_hash_hmac_md5; 143 case SADB_AALG_SHA1HMAC: 144 return &auth_hash_hmac_sha1; 145 case SADB_X_AALG_RIPEMD160HMAC: 146 return &auth_hash_hmac_ripemd_160; 147 case SADB_X_AALG_MD5: 148 return &auth_hash_key_md5; 149 case SADB_X_AALG_SHA: 150 return &auth_hash_key_sha1; 151 case SADB_X_AALG_SHA2_256: 152 return &auth_hash_hmac_sha2_256; 153 case SADB_X_AALG_SHA2_384: 154 return &auth_hash_hmac_sha2_384; 155 case SADB_X_AALG_SHA2_512: 156 return &auth_hash_hmac_sha2_512; 157 } 158 return NULL; 159 } 160 161 size_t 162 ah_hdrsiz(struct secasvar *sav) 163 { 164 size_t size; 165 166 if (sav != NULL) { 167 int authsize; 168 IPSEC_ASSERT(sav->tdb_authalgxform != NULL, ("null xform")); 169 /*XXX not right for null algorithm--does it matter??*/ 170 authsize = AUTHSIZE(sav); 171 size = roundup(authsize, sizeof (u_int32_t)) + HDRSIZE(sav); 172 } else { 173 /* default guess */ 174 size = sizeof (struct ah) + sizeof (u_int32_t) + 16; 175 } 176 return size; 177 } 178 179 /* 180 * NB: public for use by esp_init. 181 */ 182 int 183 ah_init0(struct secasvar *sav, struct xformsw *xsp, struct cryptoini *cria) 184 { 185 struct auth_hash *thash; 186 int keylen; 187 188 thash = ah_algorithm_lookup(sav->alg_auth); 189 if (thash == NULL) { 190 DPRINTF(("%s: unsupported authentication algorithm %u\n", 191 __func__, sav->alg_auth)); 192 return EINVAL; 193 } 194 /* 195 * Verify the replay state block allocation is consistent with 196 * the protocol type. We check here so we can make assumptions 197 * later during protocol processing. 198 */ 199 /* NB: replay state is setup elsewhere (sigh) */ 200 if (((sav->flags&SADB_X_EXT_OLD) == 0) ^ (sav->replay != NULL)) { 201 DPRINTF(("%s: replay state block inconsistency, " 202 "%s algorithm %s replay state\n", __func__, 203 (sav->flags & SADB_X_EXT_OLD) ? "old" : "new", 204 sav->replay == NULL ? "without" : "with")); 205 return EINVAL; 206 } 207 if (sav->key_auth == NULL) { 208 DPRINTF(("%s: no authentication key for %s algorithm\n", 209 __func__, thash->name)); 210 return EINVAL; 211 } 212 keylen = _KEYLEN(sav->key_auth); 213 if (keylen != thash->keysize && thash->keysize != 0) { 214 DPRINTF(("%s: invalid keylength %d, algorithm %s requires " 215 "keysize %d\n", __func__, 216 keylen, thash->name, thash->keysize)); 217 return EINVAL; 218 } 219 220 sav->tdb_xform = xsp; 221 sav->tdb_authalgxform = thash; 222 223 /* Initialize crypto session. */ 224 bzero(cria, sizeof (*cria)); 225 cria->cri_alg = sav->tdb_authalgxform->type; 226 cria->cri_klen = _KEYBITS(sav->key_auth); 227 cria->cri_key = sav->key_auth->key_data; 228 cria->cri_mlen = AUTHSIZE(sav); 229 230 return 0; 231 } 232 233 /* 234 * ah_init() is called when an SPI is being set up. 235 */ 236 static int 237 ah_init(struct secasvar *sav, struct xformsw *xsp) 238 { 239 struct cryptoini cria; 240 int error; 241 242 error = ah_init0(sav, xsp, &cria); 243 return error ? error : 244 crypto_newsession(&sav->tdb_cryptoid, &cria, V_crypto_support); 245 } 246 247 /* 248 * Paranoia. 249 * 250 * NB: public for use by esp_zeroize (XXX). 251 */ 252 int 253 ah_zeroize(struct secasvar *sav) 254 { 255 int err; 256 257 if (sav->key_auth) 258 bzero(sav->key_auth->key_data, _KEYLEN(sav->key_auth)); 259 260 err = crypto_freesession(sav->tdb_cryptoid); 261 sav->tdb_cryptoid = 0; 262 sav->tdb_authalgxform = NULL; 263 sav->tdb_xform = NULL; 264 return err; 265 } 266 267 /* 268 * Massage IPv4/IPv6 headers for AH processing. 269 */ 270 static int 271 ah_massage_headers(struct mbuf **m0, int proto, int skip, int alg, int out) 272 { 273 struct mbuf *m = *m0; 274 unsigned char *ptr; 275 int off, count; 276 277 #ifdef INET 278 struct ip *ip; 279 #endif /* INET */ 280 281 #ifdef INET6 282 struct ip6_ext *ip6e; 283 struct ip6_hdr ip6; 284 int alloc, len, ad; 285 #endif /* INET6 */ 286 287 switch (proto) { 288 #ifdef INET 289 case AF_INET: 290 /* 291 * This is the least painful way of dealing with IPv4 header 292 * and option processing -- just make sure they're in 293 * contiguous memory. 294 */ 295 *m0 = m = m_pullup(m, skip); 296 if (m == NULL) { 297 DPRINTF(("%s: m_pullup failed\n", __func__)); 298 return ENOBUFS; 299 } 300 301 /* Fix the IP header */ 302 ip = mtod(m, struct ip *); 303 if (V_ah_cleartos) 304 ip->ip_tos = 0; 305 ip->ip_ttl = 0; 306 ip->ip_sum = 0; 307 308 /* 309 * On input, fix ip_len which has been byte-swapped 310 * at ip_input(). 311 */ 312 if (!out) { 313 ip->ip_len = htons(ip->ip_len + skip); 314 315 if (alg == CRYPTO_MD5_KPDK || alg == CRYPTO_SHA1_KPDK) 316 ip->ip_off = htons(ip->ip_off & IP_DF); 317 else 318 ip->ip_off = 0; 319 } else { 320 if (alg == CRYPTO_MD5_KPDK || alg == CRYPTO_SHA1_KPDK) 321 ip->ip_off = htons(ntohs(ip->ip_off) & IP_DF); 322 else 323 ip->ip_off = 0; 324 } 325 326 ptr = mtod(m, unsigned char *) + sizeof(struct ip); 327 328 /* IPv4 option processing */ 329 for (off = sizeof(struct ip); off < skip;) { 330 if (ptr[off] == IPOPT_EOL || ptr[off] == IPOPT_NOP || 331 off + 1 < skip) 332 ; 333 else { 334 DPRINTF(("%s: illegal IPv4 option length for " 335 "option %d\n", __func__, ptr[off])); 336 337 m_freem(m); 338 return EINVAL; 339 } 340 341 switch (ptr[off]) { 342 case IPOPT_EOL: 343 off = skip; /* End the loop. */ 344 break; 345 346 case IPOPT_NOP: 347 off++; 348 break; 349 350 case IPOPT_SECURITY: /* 0x82 */ 351 case 0x85: /* Extended security. */ 352 case 0x86: /* Commercial security. */ 353 case 0x94: /* Router alert */ 354 case 0x95: /* RFC1770 */ 355 /* Sanity check for option length. */ 356 if (ptr[off + 1] < 2) { 357 DPRINTF(("%s: illegal IPv4 option " 358 "length for option %d\n", 359 __func__, ptr[off])); 360 361 m_freem(m); 362 return EINVAL; 363 } 364 365 off += ptr[off + 1]; 366 break; 367 368 case IPOPT_LSRR: 369 case IPOPT_SSRR: 370 /* Sanity check for option length. */ 371 if (ptr[off + 1] < 2) { 372 DPRINTF(("%s: illegal IPv4 option " 373 "length for option %d\n", 374 __func__, ptr[off])); 375 376 m_freem(m); 377 return EINVAL; 378 } 379 380 /* 381 * On output, if we have either of the 382 * source routing options, we should 383 * swap the destination address of the 384 * IP header with the last address 385 * specified in the option, as that is 386 * what the destination's IP header 387 * will look like. 388 */ 389 if (out) 390 bcopy(ptr + off + ptr[off + 1] - 391 sizeof(struct in_addr), 392 &(ip->ip_dst), sizeof(struct in_addr)); 393 394 /* Fall through */ 395 default: 396 /* Sanity check for option length. */ 397 if (ptr[off + 1] < 2) { 398 DPRINTF(("%s: illegal IPv4 option " 399 "length for option %d\n", 400 __func__, ptr[off])); 401 m_freem(m); 402 return EINVAL; 403 } 404 405 /* Zeroize all other options. */ 406 count = ptr[off + 1]; 407 bcopy(ipseczeroes, ptr, count); 408 off += count; 409 break; 410 } 411 412 /* Sanity check. */ 413 if (off > skip) { 414 DPRINTF(("%s: malformed IPv4 options header\n", 415 __func__)); 416 417 m_freem(m); 418 return EINVAL; 419 } 420 } 421 422 break; 423 #endif /* INET */ 424 425 #ifdef INET6 426 case AF_INET6: /* Ugly... */ 427 /* Copy and "cook" the IPv6 header. */ 428 m_copydata(m, 0, sizeof(ip6), (caddr_t) &ip6); 429 430 /* We don't do IPv6 Jumbograms. */ 431 if (ip6.ip6_plen == 0) { 432 DPRINTF(("%s: unsupported IPv6 jumbogram\n", __func__)); 433 m_freem(m); 434 return EMSGSIZE; 435 } 436 437 ip6.ip6_flow = 0; 438 ip6.ip6_hlim = 0; 439 ip6.ip6_vfc &= ~IPV6_VERSION_MASK; 440 ip6.ip6_vfc |= IPV6_VERSION; 441 442 /* Scoped address handling. */ 443 if (IN6_IS_SCOPE_LINKLOCAL(&ip6.ip6_src)) 444 ip6.ip6_src.s6_addr16[1] = 0; 445 if (IN6_IS_SCOPE_LINKLOCAL(&ip6.ip6_dst)) 446 ip6.ip6_dst.s6_addr16[1] = 0; 447 448 /* Done with IPv6 header. */ 449 m_copyback(m, 0, sizeof(struct ip6_hdr), (caddr_t) &ip6); 450 451 /* Let's deal with the remaining headers (if any). */ 452 if (skip - sizeof(struct ip6_hdr) > 0) { 453 if (m->m_len <= skip) { 454 ptr = (unsigned char *) malloc( 455 skip - sizeof(struct ip6_hdr), 456 M_XDATA, M_NOWAIT); 457 if (ptr == NULL) { 458 DPRINTF(("%s: failed to allocate memory" 459 "for IPv6 headers\n",__func__)); 460 m_freem(m); 461 return ENOBUFS; 462 } 463 464 /* 465 * Copy all the protocol headers after 466 * the IPv6 header. 467 */ 468 m_copydata(m, sizeof(struct ip6_hdr), 469 skip - sizeof(struct ip6_hdr), ptr); 470 alloc = 1; 471 } else { 472 /* No need to allocate memory. */ 473 ptr = mtod(m, unsigned char *) + 474 sizeof(struct ip6_hdr); 475 alloc = 0; 476 } 477 } else 478 break; 479 480 off = ip6.ip6_nxt & 0xff; /* Next header type. */ 481 482 for (len = 0; len < skip - sizeof(struct ip6_hdr);) 483 switch (off) { 484 case IPPROTO_HOPOPTS: 485 case IPPROTO_DSTOPTS: 486 ip6e = (struct ip6_ext *) (ptr + len); 487 488 /* 489 * Process the mutable/immutable 490 * options -- borrows heavily from the 491 * KAME code. 492 */ 493 for (count = len + sizeof(struct ip6_ext); 494 count < len + ((ip6e->ip6e_len + 1) << 3);) { 495 if (ptr[count] == IP6OPT_PAD1) { 496 count++; 497 continue; /* Skip padding. */ 498 } 499 500 /* Sanity check. */ 501 if (count > len + 502 ((ip6e->ip6e_len + 1) << 3)) { 503 m_freem(m); 504 505 /* Free, if we allocated. */ 506 if (alloc) 507 free(ptr, M_XDATA); 508 return EINVAL; 509 } 510 511 ad = ptr[count + 1]; 512 513 /* If mutable option, zeroize. */ 514 if (ptr[count] & IP6OPT_MUTABLE) 515 bcopy(ipseczeroes, ptr + count, 516 ptr[count + 1]); 517 518 count += ad; 519 520 /* Sanity check. */ 521 if (count > 522 skip - sizeof(struct ip6_hdr)) { 523 m_freem(m); 524 525 /* Free, if we allocated. */ 526 if (alloc) 527 free(ptr, M_XDATA); 528 return EINVAL; 529 } 530 } 531 532 /* Advance. */ 533 len += ((ip6e->ip6e_len + 1) << 3); 534 off = ip6e->ip6e_nxt; 535 break; 536 537 case IPPROTO_ROUTING: 538 /* 539 * Always include routing headers in 540 * computation. 541 */ 542 ip6e = (struct ip6_ext *) (ptr + len); 543 len += ((ip6e->ip6e_len + 1) << 3); 544 off = ip6e->ip6e_nxt; 545 break; 546 547 default: 548 DPRINTF(("%s: unexpected IPv6 header type %d", 549 __func__, off)); 550 if (alloc) 551 free(ptr, M_XDATA); 552 m_freem(m); 553 return EINVAL; 554 } 555 556 /* Copyback and free, if we allocated. */ 557 if (alloc) { 558 m_copyback(m, sizeof(struct ip6_hdr), 559 skip - sizeof(struct ip6_hdr), ptr); 560 free(ptr, M_XDATA); 561 } 562 563 break; 564 #endif /* INET6 */ 565 } 566 567 return 0; 568 } 569 570 /* 571 * ah_input() gets called to verify that an input packet 572 * passes authentication. 573 */ 574 static int 575 ah_input(struct mbuf *m, struct secasvar *sav, int skip, int protoff) 576 { 577 struct auth_hash *ahx; 578 struct tdb_ident *tdbi; 579 struct tdb_crypto *tc; 580 struct m_tag *mtag; 581 struct newah *ah; 582 int hl, rplen, authsize; 583 584 struct cryptodesc *crda; 585 struct cryptop *crp; 586 587 IPSEC_ASSERT(sav != NULL, ("null SA")); 588 IPSEC_ASSERT(sav->key_auth != NULL, ("null authentication key")); 589 IPSEC_ASSERT(sav->tdb_authalgxform != NULL, 590 ("null authentication xform")); 591 592 /* Figure out header size. */ 593 rplen = HDRSIZE(sav); 594 595 /* XXX don't pullup, just copy header */ 596 IP6_EXTHDR_GET(ah, struct newah *, m, skip, rplen); 597 if (ah == NULL) { 598 DPRINTF(("ah_input: cannot pullup header\n")); 599 V_ahstat.ahs_hdrops++; /*XXX*/ 600 m_freem(m); 601 return ENOBUFS; 602 } 603 604 /* Check replay window, if applicable. */ 605 if (sav->replay && !ipsec_chkreplay(ntohl(ah->ah_seq), sav)) { 606 V_ahstat.ahs_replay++; 607 DPRINTF(("%s: packet replay failure: %s\n", __func__, 608 ipsec_logsastr(sav))); 609 m_freem(m); 610 return ENOBUFS; 611 } 612 613 /* Verify AH header length. */ 614 hl = ah->ah_len * sizeof (u_int32_t); 615 ahx = sav->tdb_authalgxform; 616 authsize = AUTHSIZE(sav); 617 if (hl != authsize + rplen - sizeof (struct ah)) { 618 DPRINTF(("%s: bad authenticator length %u (expecting %lu)" 619 " for packet in SA %s/%08lx\n", __func__, 620 hl, (u_long) (authsize + rplen - sizeof (struct ah)), 621 ipsec_address(&sav->sah->saidx.dst), 622 (u_long) ntohl(sav->spi))); 623 V_ahstat.ahs_badauthl++; 624 m_freem(m); 625 return EACCES; 626 } 627 V_ahstat.ahs_ibytes += m->m_pkthdr.len - skip - hl; 628 629 /* Get crypto descriptors. */ 630 crp = crypto_getreq(1); 631 if (crp == NULL) { 632 DPRINTF(("%s: failed to acquire crypto descriptor\n",__func__)); 633 V_ahstat.ahs_crypto++; 634 m_freem(m); 635 return ENOBUFS; 636 } 637 638 crda = crp->crp_desc; 639 IPSEC_ASSERT(crda != NULL, ("null crypto descriptor")); 640 641 crda->crd_skip = 0; 642 crda->crd_len = m->m_pkthdr.len; 643 crda->crd_inject = skip + rplen; 644 645 /* Authentication operation. */ 646 crda->crd_alg = ahx->type; 647 crda->crd_klen = _KEYBITS(sav->key_auth); 648 crda->crd_key = sav->key_auth->key_data; 649 650 /* Find out if we've already done crypto. */ 651 for (mtag = m_tag_find(m, PACKET_TAG_IPSEC_IN_CRYPTO_DONE, NULL); 652 mtag != NULL; 653 mtag = m_tag_find(m, PACKET_TAG_IPSEC_IN_CRYPTO_DONE, mtag)) { 654 tdbi = (struct tdb_ident *) (mtag + 1); 655 if (tdbi->proto == sav->sah->saidx.proto && 656 tdbi->spi == sav->spi && 657 !bcmp(&tdbi->dst, &sav->sah->saidx.dst, 658 sizeof (union sockaddr_union))) 659 break; 660 } 661 662 /* Allocate IPsec-specific opaque crypto info. */ 663 if (mtag == NULL) { 664 tc = (struct tdb_crypto *) malloc(sizeof (struct tdb_crypto) + 665 skip + rplen + authsize, M_XDATA, M_NOWAIT|M_ZERO); 666 } else { 667 /* Hash verification has already been done successfully. */ 668 tc = (struct tdb_crypto *) malloc(sizeof (struct tdb_crypto), 669 M_XDATA, M_NOWAIT|M_ZERO); 670 } 671 if (tc == NULL) { 672 DPRINTF(("%s: failed to allocate tdb_crypto\n", __func__)); 673 V_ahstat.ahs_crypto++; 674 crypto_freereq(crp); 675 m_freem(m); 676 return ENOBUFS; 677 } 678 679 /* Only save information if crypto processing is needed. */ 680 if (mtag == NULL) { 681 int error; 682 683 /* 684 * Save the authenticator, the skipped portion of the packet, 685 * and the AH header. 686 */ 687 m_copydata(m, 0, skip + rplen + authsize, (caddr_t)(tc+1)); 688 689 /* Zeroize the authenticator on the packet. */ 690 m_copyback(m, skip + rplen, authsize, ipseczeroes); 691 692 /* "Massage" the packet headers for crypto processing. */ 693 error = ah_massage_headers(&m, sav->sah->saidx.dst.sa.sa_family, 694 skip, ahx->type, 0); 695 if (error != 0) { 696 /* NB: mbuf is free'd by ah_massage_headers */ 697 V_ahstat.ahs_hdrops++; 698 free(tc, M_XDATA); 699 crypto_freereq(crp); 700 return error; 701 } 702 } 703 704 /* Crypto operation descriptor. */ 705 crp->crp_ilen = m->m_pkthdr.len; /* Total input length. */ 706 crp->crp_flags = CRYPTO_F_IMBUF | CRYPTO_F_CBIFSYNC; 707 crp->crp_buf = (caddr_t) m; 708 crp->crp_callback = ah_input_cb; 709 crp->crp_sid = sav->tdb_cryptoid; 710 crp->crp_opaque = (caddr_t) tc; 711 712 /* These are passed as-is to the callback. */ 713 tc->tc_spi = sav->spi; 714 tc->tc_dst = sav->sah->saidx.dst; 715 tc->tc_proto = sav->sah->saidx.proto; 716 tc->tc_nxt = ah->ah_nxt; 717 tc->tc_protoff = protoff; 718 tc->tc_skip = skip; 719 tc->tc_ptr = (caddr_t) mtag; /* Save the mtag we've identified. */ 720 KEY_ADDREFSA(sav); 721 tc->tc_sav = sav; 722 723 if (mtag == NULL) 724 return crypto_dispatch(crp); 725 else 726 return ah_input_cb(crp); 727 } 728 729 /* 730 * AH input callback from the crypto driver. 731 */ 732 static int 733 ah_input_cb(struct cryptop *crp) 734 { 735 int rplen, error, skip, protoff; 736 unsigned char calc[AH_ALEN_MAX]; 737 struct mbuf *m; 738 struct cryptodesc *crd; 739 struct auth_hash *ahx; 740 struct tdb_crypto *tc; 741 struct m_tag *mtag; 742 struct secasvar *sav; 743 struct secasindex *saidx; 744 u_int8_t nxt; 745 caddr_t ptr; 746 int authsize; 747 748 crd = crp->crp_desc; 749 750 tc = (struct tdb_crypto *) crp->crp_opaque; 751 IPSEC_ASSERT(tc != NULL, ("null opaque crypto data area!")); 752 skip = tc->tc_skip; 753 nxt = tc->tc_nxt; 754 protoff = tc->tc_protoff; 755 mtag = (struct m_tag *) tc->tc_ptr; 756 m = (struct mbuf *) crp->crp_buf; 757 758 sav = tc->tc_sav; 759 IPSEC_ASSERT(sav != NULL, ("null SA!")); 760 761 saidx = &sav->sah->saidx; 762 IPSEC_ASSERT(saidx->dst.sa.sa_family == AF_INET || 763 saidx->dst.sa.sa_family == AF_INET6, 764 ("unexpected protocol family %u", saidx->dst.sa.sa_family)); 765 766 ahx = (struct auth_hash *) sav->tdb_authalgxform; 767 768 /* Check for crypto errors. */ 769 if (crp->crp_etype) { 770 if (sav->tdb_cryptoid != 0) 771 sav->tdb_cryptoid = crp->crp_sid; 772 773 if (crp->crp_etype == EAGAIN) 774 return (crypto_dispatch(crp)); 775 776 V_ahstat.ahs_noxform++; 777 DPRINTF(("%s: crypto error %d\n", __func__, crp->crp_etype)); 778 error = crp->crp_etype; 779 goto bad; 780 } else { 781 V_ahstat.ahs_hist[sav->alg_auth]++; 782 crypto_freereq(crp); /* No longer needed. */ 783 crp = NULL; 784 } 785 786 /* Shouldn't happen... */ 787 if (m == NULL) { 788 V_ahstat.ahs_crypto++; 789 DPRINTF(("%s: bogus returned buffer from crypto\n", __func__)); 790 error = EINVAL; 791 goto bad; 792 } 793 794 /* Figure out header size. */ 795 rplen = HDRSIZE(sav); 796 authsize = AUTHSIZE(sav); 797 798 /* Copy authenticator off the packet. */ 799 m_copydata(m, skip + rplen, authsize, calc); 800 801 /* 802 * If we have an mtag, we don't need to verify the authenticator -- 803 * it has been verified by an IPsec-aware NIC. 804 */ 805 if (mtag == NULL) { 806 ptr = (caddr_t) (tc + 1); 807 808 /* Verify authenticator. */ 809 if (bcmp(ptr + skip + rplen, calc, authsize)) { 810 DPRINTF(("%s: authentication hash mismatch for packet " 811 "in SA %s/%08lx\n", __func__, 812 ipsec_address(&saidx->dst), 813 (u_long) ntohl(sav->spi))); 814 V_ahstat.ahs_badauth++; 815 error = EACCES; 816 goto bad; 817 } 818 819 /* Fix the Next Protocol field. */ 820 ((u_int8_t *) ptr)[protoff] = nxt; 821 822 /* Copyback the saved (uncooked) network headers. */ 823 m_copyback(m, 0, skip, ptr); 824 } else { 825 /* Fix the Next Protocol field. */ 826 m_copyback(m, protoff, sizeof(u_int8_t), &nxt); 827 } 828 829 free(tc, M_XDATA), tc = NULL; /* No longer needed */ 830 831 /* 832 * Header is now authenticated. 833 */ 834 m->m_flags |= M_AUTHIPHDR|M_AUTHIPDGM; 835 836 /* 837 * Update replay sequence number, if appropriate. 838 */ 839 if (sav->replay) { 840 u_int32_t seq; 841 842 m_copydata(m, skip + offsetof(struct newah, ah_seq), 843 sizeof (seq), (caddr_t) &seq); 844 if (ipsec_updatereplay(ntohl(seq), sav)) { 845 V_ahstat.ahs_replay++; 846 error = ENOBUFS; /*XXX as above*/ 847 goto bad; 848 } 849 } 850 851 /* 852 * Remove the AH header and authenticator from the mbuf. 853 */ 854 error = m_striphdr(m, skip, rplen + authsize); 855 if (error) { 856 DPRINTF(("%s: mangled mbuf chain for SA %s/%08lx\n", __func__, 857 ipsec_address(&saidx->dst), (u_long) ntohl(sav->spi))); 858 859 V_ahstat.ahs_hdrops++; 860 goto bad; 861 } 862 863 switch (saidx->dst.sa.sa_family) { 864 #ifdef INET6 865 case AF_INET6: 866 error = ipsec6_common_input_cb(m, sav, skip, protoff, mtag); 867 break; 868 #endif 869 #ifdef INET 870 case AF_INET: 871 error = ipsec4_common_input_cb(m, sav, skip, protoff, mtag); 872 break; 873 #endif 874 default: 875 panic("%s: Unexpected address family: %d saidx=%p", __func__, 876 saidx->dst.sa.sa_family, saidx); 877 } 878 879 KEY_FREESAV(&sav); 880 return error; 881 bad: 882 if (sav) 883 KEY_FREESAV(&sav); 884 if (m != NULL) 885 m_freem(m); 886 if (tc != NULL) 887 free(tc, M_XDATA); 888 if (crp != NULL) 889 crypto_freereq(crp); 890 return error; 891 } 892 893 /* 894 * AH output routine, called by ipsec[46]_process_packet(). 895 */ 896 static int 897 ah_output( 898 struct mbuf *m, 899 struct ipsecrequest *isr, 900 struct mbuf **mp, 901 int skip, 902 int protoff) 903 { 904 struct secasvar *sav; 905 struct auth_hash *ahx; 906 struct cryptodesc *crda; 907 struct tdb_crypto *tc; 908 struct mbuf *mi; 909 struct cryptop *crp; 910 u_int16_t iplen; 911 int error, rplen, authsize, maxpacketsize, roff; 912 u_int8_t prot; 913 struct newah *ah; 914 915 sav = isr->sav; 916 IPSEC_ASSERT(sav != NULL, ("null SA")); 917 ahx = sav->tdb_authalgxform; 918 IPSEC_ASSERT(ahx != NULL, ("null authentication xform")); 919 920 V_ahstat.ahs_output++; 921 922 /* Figure out header size. */ 923 rplen = HDRSIZE(sav); 924 925 /* Check for maximum packet size violations. */ 926 switch (sav->sah->saidx.dst.sa.sa_family) { 927 #ifdef INET 928 case AF_INET: 929 maxpacketsize = IP_MAXPACKET; 930 break; 931 #endif /* INET */ 932 #ifdef INET6 933 case AF_INET6: 934 maxpacketsize = IPV6_MAXPACKET; 935 break; 936 #endif /* INET6 */ 937 default: 938 DPRINTF(("%s: unknown/unsupported protocol family %u, " 939 "SA %s/%08lx\n", __func__, 940 sav->sah->saidx.dst.sa.sa_family, 941 ipsec_address(&sav->sah->saidx.dst), 942 (u_long) ntohl(sav->spi))); 943 V_ahstat.ahs_nopf++; 944 error = EPFNOSUPPORT; 945 goto bad; 946 } 947 authsize = AUTHSIZE(sav); 948 if (rplen + authsize + m->m_pkthdr.len > maxpacketsize) { 949 DPRINTF(("%s: packet in SA %s/%08lx got too big " 950 "(len %u, max len %u)\n", __func__, 951 ipsec_address(&sav->sah->saidx.dst), 952 (u_long) ntohl(sav->spi), 953 rplen + authsize + m->m_pkthdr.len, maxpacketsize)); 954 V_ahstat.ahs_toobig++; 955 error = EMSGSIZE; 956 goto bad; 957 } 958 959 /* Update the counters. */ 960 V_ahstat.ahs_obytes += m->m_pkthdr.len - skip; 961 962 m = m_unshare(m, M_NOWAIT); 963 if (m == NULL) { 964 DPRINTF(("%s: cannot clone mbuf chain, SA %s/%08lx\n", __func__, 965 ipsec_address(&sav->sah->saidx.dst), 966 (u_long) ntohl(sav->spi))); 967 V_ahstat.ahs_hdrops++; 968 error = ENOBUFS; 969 goto bad; 970 } 971 972 /* Inject AH header. */ 973 mi = m_makespace(m, skip, rplen + authsize, &roff); 974 if (mi == NULL) { 975 DPRINTF(("%s: failed to inject %u byte AH header for SA " 976 "%s/%08lx\n", __func__, 977 rplen + authsize, 978 ipsec_address(&sav->sah->saidx.dst), 979 (u_long) ntohl(sav->spi))); 980 V_ahstat.ahs_hdrops++; /*XXX differs from openbsd */ 981 error = ENOBUFS; 982 goto bad; 983 } 984 985 /* 986 * The AH header is guaranteed by m_makespace() to be in 987 * contiguous memory, at roff bytes offset into the returned mbuf. 988 */ 989 ah = (struct newah *)(mtod(mi, caddr_t) + roff); 990 991 /* Initialize the AH header. */ 992 m_copydata(m, protoff, sizeof(u_int8_t), (caddr_t) &ah->ah_nxt); 993 ah->ah_len = (rplen + authsize - sizeof(struct ah)) / sizeof(u_int32_t); 994 ah->ah_reserve = 0; 995 ah->ah_spi = sav->spi; 996 997 /* Zeroize authenticator. */ 998 m_copyback(m, skip + rplen, authsize, ipseczeroes); 999 1000 /* Insert packet replay counter, as requested. */ 1001 if (sav->replay) { 1002 if (sav->replay->count == ~0 && 1003 (sav->flags & SADB_X_EXT_CYCSEQ) == 0) { 1004 DPRINTF(("%s: replay counter wrapped for SA %s/%08lx\n", 1005 __func__, 1006 ipsec_address(&sav->sah->saidx.dst), 1007 (u_long) ntohl(sav->spi))); 1008 V_ahstat.ahs_wrap++; 1009 error = EINVAL; 1010 goto bad; 1011 } 1012 #ifdef REGRESSION 1013 /* Emulate replay attack when ipsec_replay is TRUE. */ 1014 if (!V_ipsec_replay) 1015 #endif 1016 sav->replay->count++; 1017 ah->ah_seq = htonl(sav->replay->count); 1018 } 1019 1020 /* Get crypto descriptors. */ 1021 crp = crypto_getreq(1); 1022 if (crp == NULL) { 1023 DPRINTF(("%s: failed to acquire crypto descriptors\n", 1024 __func__)); 1025 V_ahstat.ahs_crypto++; 1026 error = ENOBUFS; 1027 goto bad; 1028 } 1029 1030 crda = crp->crp_desc; 1031 1032 crda->crd_skip = 0; 1033 crda->crd_inject = skip + rplen; 1034 crda->crd_len = m->m_pkthdr.len; 1035 1036 /* Authentication operation. */ 1037 crda->crd_alg = ahx->type; 1038 crda->crd_key = sav->key_auth->key_data; 1039 crda->crd_klen = _KEYBITS(sav->key_auth); 1040 1041 /* Allocate IPsec-specific opaque crypto info. */ 1042 tc = (struct tdb_crypto *) malloc( 1043 sizeof(struct tdb_crypto) + skip, M_XDATA, M_NOWAIT|M_ZERO); 1044 if (tc == NULL) { 1045 crypto_freereq(crp); 1046 DPRINTF(("%s: failed to allocate tdb_crypto\n", __func__)); 1047 V_ahstat.ahs_crypto++; 1048 error = ENOBUFS; 1049 goto bad; 1050 } 1051 1052 /* Save the skipped portion of the packet. */ 1053 m_copydata(m, 0, skip, (caddr_t) (tc + 1)); 1054 1055 /* 1056 * Fix IP header length on the header used for 1057 * authentication. We don't need to fix the original 1058 * header length as it will be fixed by our caller. 1059 */ 1060 switch (sav->sah->saidx.dst.sa.sa_family) { 1061 #ifdef INET 1062 case AF_INET: 1063 bcopy(((caddr_t)(tc + 1)) + 1064 offsetof(struct ip, ip_len), 1065 (caddr_t) &iplen, sizeof(u_int16_t)); 1066 iplen = htons(ntohs(iplen) + rplen + authsize); 1067 m_copyback(m, offsetof(struct ip, ip_len), 1068 sizeof(u_int16_t), (caddr_t) &iplen); 1069 break; 1070 #endif /* INET */ 1071 1072 #ifdef INET6 1073 case AF_INET6: 1074 bcopy(((caddr_t)(tc + 1)) + 1075 offsetof(struct ip6_hdr, ip6_plen), 1076 (caddr_t) &iplen, sizeof(u_int16_t)); 1077 iplen = htons(ntohs(iplen) + rplen + authsize); 1078 m_copyback(m, offsetof(struct ip6_hdr, ip6_plen), 1079 sizeof(u_int16_t), (caddr_t) &iplen); 1080 break; 1081 #endif /* INET6 */ 1082 } 1083 1084 /* Fix the Next Header field in saved header. */ 1085 ((u_int8_t *) (tc + 1))[protoff] = IPPROTO_AH; 1086 1087 /* Update the Next Protocol field in the IP header. */ 1088 prot = IPPROTO_AH; 1089 m_copyback(m, protoff, sizeof(u_int8_t), (caddr_t) &prot); 1090 1091 /* "Massage" the packet headers for crypto processing. */ 1092 error = ah_massage_headers(&m, sav->sah->saidx.dst.sa.sa_family, 1093 skip, ahx->type, 1); 1094 if (error != 0) { 1095 m = NULL; /* mbuf was free'd by ah_massage_headers. */ 1096 free(tc, M_XDATA); 1097 crypto_freereq(crp); 1098 goto bad; 1099 } 1100 1101 /* Crypto operation descriptor. */ 1102 crp->crp_ilen = m->m_pkthdr.len; /* Total input length. */ 1103 crp->crp_flags = CRYPTO_F_IMBUF | CRYPTO_F_CBIFSYNC; 1104 crp->crp_buf = (caddr_t) m; 1105 crp->crp_callback = ah_output_cb; 1106 crp->crp_sid = sav->tdb_cryptoid; 1107 crp->crp_opaque = (caddr_t) tc; 1108 1109 /* These are passed as-is to the callback. */ 1110 tc->tc_isr = isr; 1111 KEY_ADDREFSA(sav); 1112 tc->tc_sav = sav; 1113 tc->tc_spi = sav->spi; 1114 tc->tc_dst = sav->sah->saidx.dst; 1115 tc->tc_proto = sav->sah->saidx.proto; 1116 tc->tc_skip = skip; 1117 tc->tc_protoff = protoff; 1118 1119 return crypto_dispatch(crp); 1120 bad: 1121 if (m) 1122 m_freem(m); 1123 return (error); 1124 } 1125 1126 /* 1127 * AH output callback from the crypto driver. 1128 */ 1129 static int 1130 ah_output_cb(struct cryptop *crp) 1131 { 1132 int skip, protoff, error; 1133 struct tdb_crypto *tc; 1134 struct ipsecrequest *isr; 1135 struct secasvar *sav; 1136 struct mbuf *m; 1137 caddr_t ptr; 1138 1139 tc = (struct tdb_crypto *) crp->crp_opaque; 1140 IPSEC_ASSERT(tc != NULL, ("null opaque data area!")); 1141 skip = tc->tc_skip; 1142 protoff = tc->tc_protoff; 1143 ptr = (caddr_t) (tc + 1); 1144 m = (struct mbuf *) crp->crp_buf; 1145 1146 isr = tc->tc_isr; 1147 IPSECREQUEST_LOCK(isr); 1148 sav = tc->tc_sav; 1149 /* With the isr lock released SA pointer can be updated. */ 1150 if (sav != isr->sav) { 1151 V_ahstat.ahs_notdb++; 1152 DPRINTF(("%s: SA expired while in crypto\n", __func__)); 1153 error = ENOBUFS; /*XXX*/ 1154 goto bad; 1155 } 1156 1157 /* Check for crypto errors. */ 1158 if (crp->crp_etype) { 1159 if (sav->tdb_cryptoid != 0) 1160 sav->tdb_cryptoid = crp->crp_sid; 1161 1162 if (crp->crp_etype == EAGAIN) { 1163 IPSECREQUEST_UNLOCK(isr); 1164 return (crypto_dispatch(crp)); 1165 } 1166 1167 V_ahstat.ahs_noxform++; 1168 DPRINTF(("%s: crypto error %d\n", __func__, crp->crp_etype)); 1169 error = crp->crp_etype; 1170 goto bad; 1171 } 1172 1173 /* Shouldn't happen... */ 1174 if (m == NULL) { 1175 V_ahstat.ahs_crypto++; 1176 DPRINTF(("%s: bogus returned buffer from crypto\n", __func__)); 1177 error = EINVAL; 1178 goto bad; 1179 } 1180 V_ahstat.ahs_hist[sav->alg_auth]++; 1181 1182 /* 1183 * Copy original headers (with the new protocol number) back 1184 * in place. 1185 */ 1186 m_copyback(m, 0, skip, ptr); 1187 1188 /* No longer needed. */ 1189 free(tc, M_XDATA); 1190 crypto_freereq(crp); 1191 1192 #ifdef REGRESSION 1193 /* Emulate man-in-the-middle attack when ipsec_integrity is TRUE. */ 1194 if (V_ipsec_integrity) { 1195 int alen; 1196 1197 /* 1198 * Corrupt HMAC if we want to test integrity verification of 1199 * the other side. 1200 */ 1201 alen = AUTHSIZE(sav); 1202 m_copyback(m, m->m_pkthdr.len - alen, alen, ipseczeroes); 1203 } 1204 #endif 1205 1206 /* NB: m is reclaimed by ipsec_process_done. */ 1207 error = ipsec_process_done(m, isr); 1208 KEY_FREESAV(&sav); 1209 IPSECREQUEST_UNLOCK(isr); 1210 return error; 1211 bad: 1212 if (sav) 1213 KEY_FREESAV(&sav); 1214 IPSECREQUEST_UNLOCK(isr); 1215 if (m) 1216 m_freem(m); 1217 free(tc, M_XDATA); 1218 crypto_freereq(crp); 1219 return error; 1220 } 1221 1222 static struct xformsw ah_xformsw = { 1223 XF_AH, XFT_AUTH, "IPsec AH", 1224 ah_init, ah_zeroize, ah_input, ah_output, 1225 }; 1226 1227 static void 1228 ah_attach(void) 1229 { 1230 1231 xform_register(&ah_xformsw); 1232 } 1233 1234 SYSINIT(ah_xform_init, SI_SUB_PROTO_DOMAIN, SI_ORDER_MIDDLE, ah_attach, NULL); 1235