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 if (alg == CRYPTO_MD5_KPDK || alg == CRYPTO_SHA1_KPDK) 309 ip->ip_off &= htons(IP_DF); 310 else 311 ip->ip_off = htons(0); 312 313 ptr = mtod(m, unsigned char *) + sizeof(struct ip); 314 315 /* IPv4 option processing */ 316 for (off = sizeof(struct ip); off < skip;) { 317 if (ptr[off] == IPOPT_EOL || ptr[off] == IPOPT_NOP || 318 off + 1 < skip) 319 ; 320 else { 321 DPRINTF(("%s: illegal IPv4 option length for " 322 "option %d\n", __func__, ptr[off])); 323 324 m_freem(m); 325 return EINVAL; 326 } 327 328 switch (ptr[off]) { 329 case IPOPT_EOL: 330 off = skip; /* End the loop. */ 331 break; 332 333 case IPOPT_NOP: 334 off++; 335 break; 336 337 case IPOPT_SECURITY: /* 0x82 */ 338 case 0x85: /* Extended security. */ 339 case 0x86: /* Commercial security. */ 340 case 0x94: /* Router alert */ 341 case 0x95: /* RFC1770 */ 342 /* Sanity check for option length. */ 343 if (ptr[off + 1] < 2) { 344 DPRINTF(("%s: illegal IPv4 option " 345 "length for option %d\n", 346 __func__, ptr[off])); 347 348 m_freem(m); 349 return EINVAL; 350 } 351 352 off += ptr[off + 1]; 353 break; 354 355 case IPOPT_LSRR: 356 case IPOPT_SSRR: 357 /* Sanity check for option length. */ 358 if (ptr[off + 1] < 2) { 359 DPRINTF(("%s: illegal IPv4 option " 360 "length for option %d\n", 361 __func__, ptr[off])); 362 363 m_freem(m); 364 return EINVAL; 365 } 366 367 /* 368 * On output, if we have either of the 369 * source routing options, we should 370 * swap the destination address of the 371 * IP header with the last address 372 * specified in the option, as that is 373 * what the destination's IP header 374 * will look like. 375 */ 376 if (out) 377 bcopy(ptr + off + ptr[off + 1] - 378 sizeof(struct in_addr), 379 &(ip->ip_dst), sizeof(struct in_addr)); 380 381 /* Fall through */ 382 default: 383 /* Sanity check for option length. */ 384 if (ptr[off + 1] < 2) { 385 DPRINTF(("%s: illegal IPv4 option " 386 "length for option %d\n", 387 __func__, ptr[off])); 388 m_freem(m); 389 return EINVAL; 390 } 391 392 /* Zeroize all other options. */ 393 count = ptr[off + 1]; 394 bcopy(ipseczeroes, ptr, count); 395 off += count; 396 break; 397 } 398 399 /* Sanity check. */ 400 if (off > skip) { 401 DPRINTF(("%s: malformed IPv4 options header\n", 402 __func__)); 403 404 m_freem(m); 405 return EINVAL; 406 } 407 } 408 409 break; 410 #endif /* INET */ 411 412 #ifdef INET6 413 case AF_INET6: /* Ugly... */ 414 /* Copy and "cook" the IPv6 header. */ 415 m_copydata(m, 0, sizeof(ip6), (caddr_t) &ip6); 416 417 /* We don't do IPv6 Jumbograms. */ 418 if (ip6.ip6_plen == 0) { 419 DPRINTF(("%s: unsupported IPv6 jumbogram\n", __func__)); 420 m_freem(m); 421 return EMSGSIZE; 422 } 423 424 ip6.ip6_flow = 0; 425 ip6.ip6_hlim = 0; 426 ip6.ip6_vfc &= ~IPV6_VERSION_MASK; 427 ip6.ip6_vfc |= IPV6_VERSION; 428 429 /* Scoped address handling. */ 430 if (IN6_IS_SCOPE_LINKLOCAL(&ip6.ip6_src)) 431 ip6.ip6_src.s6_addr16[1] = 0; 432 if (IN6_IS_SCOPE_LINKLOCAL(&ip6.ip6_dst)) 433 ip6.ip6_dst.s6_addr16[1] = 0; 434 435 /* Done with IPv6 header. */ 436 m_copyback(m, 0, sizeof(struct ip6_hdr), (caddr_t) &ip6); 437 438 /* Let's deal with the remaining headers (if any). */ 439 if (skip - sizeof(struct ip6_hdr) > 0) { 440 if (m->m_len <= skip) { 441 ptr = (unsigned char *) malloc( 442 skip - sizeof(struct ip6_hdr), 443 M_XDATA, M_NOWAIT); 444 if (ptr == NULL) { 445 DPRINTF(("%s: failed to allocate memory" 446 "for IPv6 headers\n",__func__)); 447 m_freem(m); 448 return ENOBUFS; 449 } 450 451 /* 452 * Copy all the protocol headers after 453 * the IPv6 header. 454 */ 455 m_copydata(m, sizeof(struct ip6_hdr), 456 skip - sizeof(struct ip6_hdr), ptr); 457 alloc = 1; 458 } else { 459 /* No need to allocate memory. */ 460 ptr = mtod(m, unsigned char *) + 461 sizeof(struct ip6_hdr); 462 alloc = 0; 463 } 464 } else 465 break; 466 467 off = ip6.ip6_nxt & 0xff; /* Next header type. */ 468 469 for (len = 0; len < skip - sizeof(struct ip6_hdr);) 470 switch (off) { 471 case IPPROTO_HOPOPTS: 472 case IPPROTO_DSTOPTS: 473 ip6e = (struct ip6_ext *) (ptr + len); 474 475 /* 476 * Process the mutable/immutable 477 * options -- borrows heavily from the 478 * KAME code. 479 */ 480 for (count = len + sizeof(struct ip6_ext); 481 count < len + ((ip6e->ip6e_len + 1) << 3);) { 482 if (ptr[count] == IP6OPT_PAD1) { 483 count++; 484 continue; /* Skip padding. */ 485 } 486 487 /* Sanity check. */ 488 if (count > len + 489 ((ip6e->ip6e_len + 1) << 3)) { 490 m_freem(m); 491 492 /* Free, if we allocated. */ 493 if (alloc) 494 free(ptr, M_XDATA); 495 return EINVAL; 496 } 497 498 ad = ptr[count + 1]; 499 500 /* If mutable option, zeroize. */ 501 if (ptr[count] & IP6OPT_MUTABLE) 502 bcopy(ipseczeroes, ptr + count, 503 ptr[count + 1]); 504 505 count += ad; 506 507 /* Sanity check. */ 508 if (count > 509 skip - sizeof(struct ip6_hdr)) { 510 m_freem(m); 511 512 /* Free, if we allocated. */ 513 if (alloc) 514 free(ptr, M_XDATA); 515 return EINVAL; 516 } 517 } 518 519 /* Advance. */ 520 len += ((ip6e->ip6e_len + 1) << 3); 521 off = ip6e->ip6e_nxt; 522 break; 523 524 case IPPROTO_ROUTING: 525 /* 526 * Always include routing headers in 527 * computation. 528 */ 529 ip6e = (struct ip6_ext *) (ptr + len); 530 len += ((ip6e->ip6e_len + 1) << 3); 531 off = ip6e->ip6e_nxt; 532 break; 533 534 default: 535 DPRINTF(("%s: unexpected IPv6 header type %d", 536 __func__, off)); 537 if (alloc) 538 free(ptr, M_XDATA); 539 m_freem(m); 540 return EINVAL; 541 } 542 543 /* Copyback and free, if we allocated. */ 544 if (alloc) { 545 m_copyback(m, sizeof(struct ip6_hdr), 546 skip - sizeof(struct ip6_hdr), ptr); 547 free(ptr, M_XDATA); 548 } 549 550 break; 551 #endif /* INET6 */ 552 } 553 554 return 0; 555 } 556 557 /* 558 * ah_input() gets called to verify that an input packet 559 * passes authentication. 560 */ 561 static int 562 ah_input(struct mbuf *m, struct secasvar *sav, int skip, int protoff) 563 { 564 struct auth_hash *ahx; 565 struct tdb_ident *tdbi; 566 struct tdb_crypto *tc; 567 struct m_tag *mtag; 568 struct newah *ah; 569 int hl, rplen, authsize; 570 571 struct cryptodesc *crda; 572 struct cryptop *crp; 573 574 IPSEC_ASSERT(sav != NULL, ("null SA")); 575 IPSEC_ASSERT(sav->key_auth != NULL, ("null authentication key")); 576 IPSEC_ASSERT(sav->tdb_authalgxform != NULL, 577 ("null authentication xform")); 578 579 /* Figure out header size. */ 580 rplen = HDRSIZE(sav); 581 582 /* XXX don't pullup, just copy header */ 583 IP6_EXTHDR_GET(ah, struct newah *, m, skip, rplen); 584 if (ah == NULL) { 585 DPRINTF(("ah_input: cannot pullup header\n")); 586 V_ahstat.ahs_hdrops++; /*XXX*/ 587 m_freem(m); 588 return ENOBUFS; 589 } 590 591 /* Check replay window, if applicable. */ 592 if (sav->replay && !ipsec_chkreplay(ntohl(ah->ah_seq), sav)) { 593 V_ahstat.ahs_replay++; 594 DPRINTF(("%s: packet replay failure: %s\n", __func__, 595 ipsec_logsastr(sav))); 596 m_freem(m); 597 return ENOBUFS; 598 } 599 600 /* Verify AH header length. */ 601 hl = ah->ah_len * sizeof (u_int32_t); 602 ahx = sav->tdb_authalgxform; 603 authsize = AUTHSIZE(sav); 604 if (hl != authsize + rplen - sizeof (struct ah)) { 605 DPRINTF(("%s: bad authenticator length %u (expecting %lu)" 606 " for packet in SA %s/%08lx\n", __func__, 607 hl, (u_long) (authsize + rplen - sizeof (struct ah)), 608 ipsec_address(&sav->sah->saidx.dst), 609 (u_long) ntohl(sav->spi))); 610 V_ahstat.ahs_badauthl++; 611 m_freem(m); 612 return EACCES; 613 } 614 V_ahstat.ahs_ibytes += m->m_pkthdr.len - skip - hl; 615 616 /* Get crypto descriptors. */ 617 crp = crypto_getreq(1); 618 if (crp == NULL) { 619 DPRINTF(("%s: failed to acquire crypto descriptor\n",__func__)); 620 V_ahstat.ahs_crypto++; 621 m_freem(m); 622 return ENOBUFS; 623 } 624 625 crda = crp->crp_desc; 626 IPSEC_ASSERT(crda != NULL, ("null crypto descriptor")); 627 628 crda->crd_skip = 0; 629 crda->crd_len = m->m_pkthdr.len; 630 crda->crd_inject = skip + rplen; 631 632 /* Authentication operation. */ 633 crda->crd_alg = ahx->type; 634 crda->crd_klen = _KEYBITS(sav->key_auth); 635 crda->crd_key = sav->key_auth->key_data; 636 637 /* Find out if we've already done crypto. */ 638 for (mtag = m_tag_find(m, PACKET_TAG_IPSEC_IN_CRYPTO_DONE, NULL); 639 mtag != NULL; 640 mtag = m_tag_find(m, PACKET_TAG_IPSEC_IN_CRYPTO_DONE, mtag)) { 641 tdbi = (struct tdb_ident *) (mtag + 1); 642 if (tdbi->proto == sav->sah->saidx.proto && 643 tdbi->spi == sav->spi && 644 !bcmp(&tdbi->dst, &sav->sah->saidx.dst, 645 sizeof (union sockaddr_union))) 646 break; 647 } 648 649 /* Allocate IPsec-specific opaque crypto info. */ 650 if (mtag == NULL) { 651 tc = (struct tdb_crypto *) malloc(sizeof (struct tdb_crypto) + 652 skip + rplen + authsize, M_XDATA, M_NOWAIT|M_ZERO); 653 } else { 654 /* Hash verification has already been done successfully. */ 655 tc = (struct tdb_crypto *) malloc(sizeof (struct tdb_crypto), 656 M_XDATA, M_NOWAIT|M_ZERO); 657 } 658 if (tc == NULL) { 659 DPRINTF(("%s: failed to allocate tdb_crypto\n", __func__)); 660 V_ahstat.ahs_crypto++; 661 crypto_freereq(crp); 662 m_freem(m); 663 return ENOBUFS; 664 } 665 666 /* Only save information if crypto processing is needed. */ 667 if (mtag == NULL) { 668 int error; 669 670 /* 671 * Save the authenticator, the skipped portion of the packet, 672 * and the AH header. 673 */ 674 m_copydata(m, 0, skip + rplen + authsize, (caddr_t)(tc+1)); 675 676 /* Zeroize the authenticator on the packet. */ 677 m_copyback(m, skip + rplen, authsize, ipseczeroes); 678 679 /* "Massage" the packet headers for crypto processing. */ 680 error = ah_massage_headers(&m, sav->sah->saidx.dst.sa.sa_family, 681 skip, ahx->type, 0); 682 if (error != 0) { 683 /* NB: mbuf is free'd by ah_massage_headers */ 684 V_ahstat.ahs_hdrops++; 685 free(tc, M_XDATA); 686 crypto_freereq(crp); 687 return error; 688 } 689 } 690 691 /* Crypto operation descriptor. */ 692 crp->crp_ilen = m->m_pkthdr.len; /* Total input length. */ 693 crp->crp_flags = CRYPTO_F_IMBUF | CRYPTO_F_CBIFSYNC; 694 crp->crp_buf = (caddr_t) m; 695 crp->crp_callback = ah_input_cb; 696 crp->crp_sid = sav->tdb_cryptoid; 697 crp->crp_opaque = (caddr_t) tc; 698 699 /* These are passed as-is to the callback. */ 700 tc->tc_spi = sav->spi; 701 tc->tc_dst = sav->sah->saidx.dst; 702 tc->tc_proto = sav->sah->saidx.proto; 703 tc->tc_nxt = ah->ah_nxt; 704 tc->tc_protoff = protoff; 705 tc->tc_skip = skip; 706 tc->tc_ptr = (caddr_t) mtag; /* Save the mtag we've identified. */ 707 KEY_ADDREFSA(sav); 708 tc->tc_sav = sav; 709 710 if (mtag == NULL) 711 return crypto_dispatch(crp); 712 else 713 return ah_input_cb(crp); 714 } 715 716 /* 717 * AH input callback from the crypto driver. 718 */ 719 static int 720 ah_input_cb(struct cryptop *crp) 721 { 722 int rplen, error, skip, protoff; 723 unsigned char calc[AH_ALEN_MAX]; 724 struct mbuf *m; 725 struct cryptodesc *crd; 726 struct auth_hash *ahx; 727 struct tdb_crypto *tc; 728 struct m_tag *mtag; 729 struct secasvar *sav; 730 struct secasindex *saidx; 731 u_int8_t nxt; 732 caddr_t ptr; 733 int authsize; 734 735 crd = crp->crp_desc; 736 737 tc = (struct tdb_crypto *) crp->crp_opaque; 738 IPSEC_ASSERT(tc != NULL, ("null opaque crypto data area!")); 739 skip = tc->tc_skip; 740 nxt = tc->tc_nxt; 741 protoff = tc->tc_protoff; 742 mtag = (struct m_tag *) tc->tc_ptr; 743 m = (struct mbuf *) crp->crp_buf; 744 745 sav = tc->tc_sav; 746 IPSEC_ASSERT(sav != NULL, ("null SA!")); 747 748 saidx = &sav->sah->saidx; 749 IPSEC_ASSERT(saidx->dst.sa.sa_family == AF_INET || 750 saidx->dst.sa.sa_family == AF_INET6, 751 ("unexpected protocol family %u", saidx->dst.sa.sa_family)); 752 753 ahx = (struct auth_hash *) sav->tdb_authalgxform; 754 755 /* Check for crypto errors. */ 756 if (crp->crp_etype) { 757 if (sav->tdb_cryptoid != 0) 758 sav->tdb_cryptoid = crp->crp_sid; 759 760 if (crp->crp_etype == EAGAIN) 761 return (crypto_dispatch(crp)); 762 763 V_ahstat.ahs_noxform++; 764 DPRINTF(("%s: crypto error %d\n", __func__, crp->crp_etype)); 765 error = crp->crp_etype; 766 goto bad; 767 } else { 768 V_ahstat.ahs_hist[sav->alg_auth]++; 769 crypto_freereq(crp); /* No longer needed. */ 770 crp = NULL; 771 } 772 773 /* Shouldn't happen... */ 774 if (m == NULL) { 775 V_ahstat.ahs_crypto++; 776 DPRINTF(("%s: bogus returned buffer from crypto\n", __func__)); 777 error = EINVAL; 778 goto bad; 779 } 780 781 /* Figure out header size. */ 782 rplen = HDRSIZE(sav); 783 authsize = AUTHSIZE(sav); 784 785 /* Copy authenticator off the packet. */ 786 m_copydata(m, skip + rplen, authsize, calc); 787 788 /* 789 * If we have an mtag, we don't need to verify the authenticator -- 790 * it has been verified by an IPsec-aware NIC. 791 */ 792 if (mtag == NULL) { 793 ptr = (caddr_t) (tc + 1); 794 795 /* Verify authenticator. */ 796 if (bcmp(ptr + skip + rplen, calc, authsize)) { 797 DPRINTF(("%s: authentication hash mismatch for packet " 798 "in SA %s/%08lx\n", __func__, 799 ipsec_address(&saidx->dst), 800 (u_long) ntohl(sav->spi))); 801 V_ahstat.ahs_badauth++; 802 error = EACCES; 803 goto bad; 804 } 805 806 /* Fix the Next Protocol field. */ 807 ((u_int8_t *) ptr)[protoff] = nxt; 808 809 /* Copyback the saved (uncooked) network headers. */ 810 m_copyback(m, 0, skip, ptr); 811 } else { 812 /* Fix the Next Protocol field. */ 813 m_copyback(m, protoff, sizeof(u_int8_t), &nxt); 814 } 815 816 free(tc, M_XDATA), tc = NULL; /* No longer needed */ 817 818 /* 819 * Header is now authenticated. 820 */ 821 m->m_flags |= M_AUTHIPHDR|M_AUTHIPDGM; 822 823 /* 824 * Update replay sequence number, if appropriate. 825 */ 826 if (sav->replay) { 827 u_int32_t seq; 828 829 m_copydata(m, skip + offsetof(struct newah, ah_seq), 830 sizeof (seq), (caddr_t) &seq); 831 if (ipsec_updatereplay(ntohl(seq), sav)) { 832 V_ahstat.ahs_replay++; 833 error = ENOBUFS; /*XXX as above*/ 834 goto bad; 835 } 836 } 837 838 /* 839 * Remove the AH header and authenticator from the mbuf. 840 */ 841 error = m_striphdr(m, skip, rplen + authsize); 842 if (error) { 843 DPRINTF(("%s: mangled mbuf chain for SA %s/%08lx\n", __func__, 844 ipsec_address(&saidx->dst), (u_long) ntohl(sav->spi))); 845 846 V_ahstat.ahs_hdrops++; 847 goto bad; 848 } 849 850 switch (saidx->dst.sa.sa_family) { 851 #ifdef INET6 852 case AF_INET6: 853 error = ipsec6_common_input_cb(m, sav, skip, protoff, mtag); 854 break; 855 #endif 856 #ifdef INET 857 case AF_INET: 858 error = ipsec4_common_input_cb(m, sav, skip, protoff, mtag); 859 break; 860 #endif 861 default: 862 panic("%s: Unexpected address family: %d saidx=%p", __func__, 863 saidx->dst.sa.sa_family, saidx); 864 } 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 struct secasvar *sav; 892 struct auth_hash *ahx; 893 struct cryptodesc *crda; 894 struct tdb_crypto *tc; 895 struct mbuf *mi; 896 struct cryptop *crp; 897 u_int16_t iplen; 898 int error, rplen, authsize, maxpacketsize, roff; 899 u_int8_t prot; 900 struct newah *ah; 901 902 sav = isr->sav; 903 IPSEC_ASSERT(sav != NULL, ("null SA")); 904 ahx = sav->tdb_authalgxform; 905 IPSEC_ASSERT(ahx != NULL, ("null authentication xform")); 906 907 V_ahstat.ahs_output++; 908 909 /* Figure out header size. */ 910 rplen = HDRSIZE(sav); 911 912 /* Check for maximum packet size violations. */ 913 switch (sav->sah->saidx.dst.sa.sa_family) { 914 #ifdef INET 915 case AF_INET: 916 maxpacketsize = IP_MAXPACKET; 917 break; 918 #endif /* INET */ 919 #ifdef INET6 920 case AF_INET6: 921 maxpacketsize = IPV6_MAXPACKET; 922 break; 923 #endif /* INET6 */ 924 default: 925 DPRINTF(("%s: unknown/unsupported protocol family %u, " 926 "SA %s/%08lx\n", __func__, 927 sav->sah->saidx.dst.sa.sa_family, 928 ipsec_address(&sav->sah->saidx.dst), 929 (u_long) ntohl(sav->spi))); 930 V_ahstat.ahs_nopf++; 931 error = EPFNOSUPPORT; 932 goto bad; 933 } 934 authsize = AUTHSIZE(sav); 935 if (rplen + authsize + m->m_pkthdr.len > maxpacketsize) { 936 DPRINTF(("%s: packet in SA %s/%08lx got too big " 937 "(len %u, max len %u)\n", __func__, 938 ipsec_address(&sav->sah->saidx.dst), 939 (u_long) ntohl(sav->spi), 940 rplen + authsize + m->m_pkthdr.len, maxpacketsize)); 941 V_ahstat.ahs_toobig++; 942 error = EMSGSIZE; 943 goto bad; 944 } 945 946 /* Update the counters. */ 947 V_ahstat.ahs_obytes += m->m_pkthdr.len - skip; 948 949 m = m_unshare(m, M_NOWAIT); 950 if (m == NULL) { 951 DPRINTF(("%s: cannot clone mbuf chain, SA %s/%08lx\n", __func__, 952 ipsec_address(&sav->sah->saidx.dst), 953 (u_long) ntohl(sav->spi))); 954 V_ahstat.ahs_hdrops++; 955 error = ENOBUFS; 956 goto bad; 957 } 958 959 /* Inject AH header. */ 960 mi = m_makespace(m, skip, rplen + authsize, &roff); 961 if (mi == NULL) { 962 DPRINTF(("%s: failed to inject %u byte AH header for SA " 963 "%s/%08lx\n", __func__, 964 rplen + authsize, 965 ipsec_address(&sav->sah->saidx.dst), 966 (u_long) ntohl(sav->spi))); 967 V_ahstat.ahs_hdrops++; /*XXX differs from openbsd */ 968 error = ENOBUFS; 969 goto bad; 970 } 971 972 /* 973 * The AH header is guaranteed by m_makespace() to be in 974 * contiguous memory, at roff bytes offset into the returned mbuf. 975 */ 976 ah = (struct newah *)(mtod(mi, caddr_t) + roff); 977 978 /* Initialize the AH header. */ 979 m_copydata(m, protoff, sizeof(u_int8_t), (caddr_t) &ah->ah_nxt); 980 ah->ah_len = (rplen + authsize - sizeof(struct ah)) / sizeof(u_int32_t); 981 ah->ah_reserve = 0; 982 ah->ah_spi = sav->spi; 983 984 /* Zeroize authenticator. */ 985 m_copyback(m, skip + rplen, authsize, ipseczeroes); 986 987 /* Insert packet replay counter, as requested. */ 988 if (sav->replay) { 989 if (sav->replay->count == ~0 && 990 (sav->flags & SADB_X_EXT_CYCSEQ) == 0) { 991 DPRINTF(("%s: replay counter wrapped for SA %s/%08lx\n", 992 __func__, 993 ipsec_address(&sav->sah->saidx.dst), 994 (u_long) ntohl(sav->spi))); 995 V_ahstat.ahs_wrap++; 996 error = EINVAL; 997 goto bad; 998 } 999 #ifdef REGRESSION 1000 /* Emulate replay attack when ipsec_replay is TRUE. */ 1001 if (!V_ipsec_replay) 1002 #endif 1003 sav->replay->count++; 1004 ah->ah_seq = htonl(sav->replay->count); 1005 } 1006 1007 /* Get crypto descriptors. */ 1008 crp = crypto_getreq(1); 1009 if (crp == NULL) { 1010 DPRINTF(("%s: failed to acquire crypto descriptors\n", 1011 __func__)); 1012 V_ahstat.ahs_crypto++; 1013 error = ENOBUFS; 1014 goto bad; 1015 } 1016 1017 crda = crp->crp_desc; 1018 1019 crda->crd_skip = 0; 1020 crda->crd_inject = skip + rplen; 1021 crda->crd_len = m->m_pkthdr.len; 1022 1023 /* Authentication operation. */ 1024 crda->crd_alg = ahx->type; 1025 crda->crd_key = sav->key_auth->key_data; 1026 crda->crd_klen = _KEYBITS(sav->key_auth); 1027 1028 /* Allocate IPsec-specific opaque crypto info. */ 1029 tc = (struct tdb_crypto *) malloc( 1030 sizeof(struct tdb_crypto) + skip, M_XDATA, M_NOWAIT|M_ZERO); 1031 if (tc == NULL) { 1032 crypto_freereq(crp); 1033 DPRINTF(("%s: failed to allocate tdb_crypto\n", __func__)); 1034 V_ahstat.ahs_crypto++; 1035 error = ENOBUFS; 1036 goto bad; 1037 } 1038 1039 /* Save the skipped portion of the packet. */ 1040 m_copydata(m, 0, skip, (caddr_t) (tc + 1)); 1041 1042 /* 1043 * Fix IP header length on the header used for 1044 * authentication. We don't need to fix the original 1045 * header length as it will be fixed by our caller. 1046 */ 1047 switch (sav->sah->saidx.dst.sa.sa_family) { 1048 #ifdef INET 1049 case AF_INET: 1050 bcopy(((caddr_t)(tc + 1)) + 1051 offsetof(struct ip, ip_len), 1052 (caddr_t) &iplen, sizeof(u_int16_t)); 1053 iplen = htons(ntohs(iplen) + rplen + authsize); 1054 m_copyback(m, offsetof(struct ip, ip_len), 1055 sizeof(u_int16_t), (caddr_t) &iplen); 1056 break; 1057 #endif /* INET */ 1058 1059 #ifdef INET6 1060 case AF_INET6: 1061 bcopy(((caddr_t)(tc + 1)) + 1062 offsetof(struct ip6_hdr, ip6_plen), 1063 (caddr_t) &iplen, sizeof(u_int16_t)); 1064 iplen = htons(ntohs(iplen) + rplen + authsize); 1065 m_copyback(m, offsetof(struct ip6_hdr, ip6_plen), 1066 sizeof(u_int16_t), (caddr_t) &iplen); 1067 break; 1068 #endif /* INET6 */ 1069 } 1070 1071 /* Fix the Next Header field in saved header. */ 1072 ((u_int8_t *) (tc + 1))[protoff] = IPPROTO_AH; 1073 1074 /* Update the Next Protocol field in the IP header. */ 1075 prot = IPPROTO_AH; 1076 m_copyback(m, protoff, sizeof(u_int8_t), (caddr_t) &prot); 1077 1078 /* "Massage" the packet headers for crypto processing. */ 1079 error = ah_massage_headers(&m, sav->sah->saidx.dst.sa.sa_family, 1080 skip, ahx->type, 1); 1081 if (error != 0) { 1082 m = NULL; /* mbuf was free'd by ah_massage_headers. */ 1083 free(tc, M_XDATA); 1084 crypto_freereq(crp); 1085 goto bad; 1086 } 1087 1088 /* Crypto operation descriptor. */ 1089 crp->crp_ilen = m->m_pkthdr.len; /* Total input length. */ 1090 crp->crp_flags = CRYPTO_F_IMBUF | CRYPTO_F_CBIFSYNC; 1091 crp->crp_buf = (caddr_t) m; 1092 crp->crp_callback = ah_output_cb; 1093 crp->crp_sid = sav->tdb_cryptoid; 1094 crp->crp_opaque = (caddr_t) tc; 1095 1096 /* These are passed as-is to the callback. */ 1097 tc->tc_isr = isr; 1098 KEY_ADDREFSA(sav); 1099 tc->tc_sav = sav; 1100 tc->tc_spi = sav->spi; 1101 tc->tc_dst = sav->sah->saidx.dst; 1102 tc->tc_proto = sav->sah->saidx.proto; 1103 tc->tc_skip = skip; 1104 tc->tc_protoff = protoff; 1105 1106 return crypto_dispatch(crp); 1107 bad: 1108 if (m) 1109 m_freem(m); 1110 return (error); 1111 } 1112 1113 /* 1114 * AH output callback from the crypto driver. 1115 */ 1116 static int 1117 ah_output_cb(struct cryptop *crp) 1118 { 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 1126 tc = (struct tdb_crypto *) crp->crp_opaque; 1127 IPSEC_ASSERT(tc != NULL, ("null opaque data area!")); 1128 skip = tc->tc_skip; 1129 protoff = tc->tc_protoff; 1130 ptr = (caddr_t) (tc + 1); 1131 m = (struct mbuf *) crp->crp_buf; 1132 1133 isr = tc->tc_isr; 1134 IPSECREQUEST_LOCK(isr); 1135 sav = tc->tc_sav; 1136 /* With the isr lock released SA pointer can be updated. */ 1137 if (sav != isr->sav) { 1138 V_ahstat.ahs_notdb++; 1139 DPRINTF(("%s: SA expired while in crypto\n", __func__)); 1140 error = ENOBUFS; /*XXX*/ 1141 goto bad; 1142 } 1143 1144 /* Check for crypto errors. */ 1145 if (crp->crp_etype) { 1146 if (sav->tdb_cryptoid != 0) 1147 sav->tdb_cryptoid = crp->crp_sid; 1148 1149 if (crp->crp_etype == EAGAIN) { 1150 IPSECREQUEST_UNLOCK(isr); 1151 return (crypto_dispatch(crp)); 1152 } 1153 1154 V_ahstat.ahs_noxform++; 1155 DPRINTF(("%s: crypto error %d\n", __func__, crp->crp_etype)); 1156 error = crp->crp_etype; 1157 goto bad; 1158 } 1159 1160 /* Shouldn't happen... */ 1161 if (m == NULL) { 1162 V_ahstat.ahs_crypto++; 1163 DPRINTF(("%s: bogus returned buffer from crypto\n", __func__)); 1164 error = EINVAL; 1165 goto bad; 1166 } 1167 V_ahstat.ahs_hist[sav->alg_auth]++; 1168 1169 /* 1170 * Copy original headers (with the new protocol number) back 1171 * in place. 1172 */ 1173 m_copyback(m, 0, skip, ptr); 1174 1175 /* No longer needed. */ 1176 free(tc, M_XDATA); 1177 crypto_freereq(crp); 1178 1179 #ifdef REGRESSION 1180 /* Emulate man-in-the-middle attack when ipsec_integrity is TRUE. */ 1181 if (V_ipsec_integrity) { 1182 int alen; 1183 1184 /* 1185 * Corrupt HMAC if we want to test integrity verification of 1186 * the other side. 1187 */ 1188 alen = AUTHSIZE(sav); 1189 m_copyback(m, m->m_pkthdr.len - alen, alen, ipseczeroes); 1190 } 1191 #endif 1192 1193 /* NB: m is reclaimed by ipsec_process_done. */ 1194 error = ipsec_process_done(m, isr); 1195 KEY_FREESAV(&sav); 1196 IPSECREQUEST_UNLOCK(isr); 1197 return error; 1198 bad: 1199 if (sav) 1200 KEY_FREESAV(&sav); 1201 IPSECREQUEST_UNLOCK(isr); 1202 if (m) 1203 m_freem(m); 1204 free(tc, M_XDATA); 1205 crypto_freereq(crp); 1206 return error; 1207 } 1208 1209 static struct xformsw ah_xformsw = { 1210 XF_AH, XFT_AUTH, "IPsec AH", 1211 ah_init, ah_zeroize, ah_input, ah_output, 1212 }; 1213 1214 static void 1215 ah_attach(void) 1216 { 1217 1218 xform_register(&ah_xformsw); 1219 } 1220 1221 SYSINIT(ah_xform_init, SI_SUB_PROTO_DOMAIN, SI_ORDER_MIDDLE, ah_attach, NULL); 1222