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 SYSCTL_DECL(_net_inet_ah); 95 SYSCTL_VNET_INT(_net_inet_ah, OID_AUTO, 96 ah_enable, CTLFLAG_RW, &VNET_NAME(ah_enable), 0, ""); 97 SYSCTL_VNET_INT(_net_inet_ah, OID_AUTO, 98 ah_cleartos, CTLFLAG_RW, &VNET_NAME(ah_cleartos), 0, ""); 99 SYSCTL_VNET_STRUCT(_net_inet_ah, IPSECCTL_STATS, 100 stats, CTLFLAG_RD, &VNET_NAME(ahstat), ahstat, ""); 101 102 static unsigned char ipseczeroes[256]; /* larger than an ip6 extension hdr */ 103 104 static int ah_input_cb(struct cryptop*); 105 static int ah_output_cb(struct cryptop*); 106 107 static int 108 ah_authsize(struct secasvar *sav) 109 { 110 111 IPSEC_ASSERT(sav != NULL, ("%s: sav == NULL", __func__)); 112 113 if (sav->flags & SADB_X_EXT_OLD) 114 return 16; 115 116 switch (sav->alg_auth) { 117 case SADB_X_AALG_SHA2_256: 118 return 16; 119 case SADB_X_AALG_SHA2_384: 120 return 24; 121 case SADB_X_AALG_SHA2_512: 122 return 32; 123 default: 124 return AH_HMAC_HASHLEN; 125 } 126 /* NOTREACHED */ 127 } 128 /* 129 * NB: this is public for use by the PF_KEY support. 130 */ 131 struct auth_hash * 132 ah_algorithm_lookup(int alg) 133 { 134 if (alg > SADB_AALG_MAX) 135 return NULL; 136 switch (alg) { 137 case SADB_X_AALG_NULL: 138 return &auth_hash_null; 139 case SADB_AALG_MD5HMAC: 140 return &auth_hash_hmac_md5; 141 case SADB_AALG_SHA1HMAC: 142 return &auth_hash_hmac_sha1; 143 case SADB_X_AALG_RIPEMD160HMAC: 144 return &auth_hash_hmac_ripemd_160; 145 case SADB_X_AALG_MD5: 146 return &auth_hash_key_md5; 147 case SADB_X_AALG_SHA: 148 return &auth_hash_key_sha1; 149 case SADB_X_AALG_SHA2_256: 150 return &auth_hash_hmac_sha2_256; 151 case SADB_X_AALG_SHA2_384: 152 return &auth_hash_hmac_sha2_384; 153 case SADB_X_AALG_SHA2_512: 154 return &auth_hash_hmac_sha2_512; 155 } 156 return NULL; 157 } 158 159 size_t 160 ah_hdrsiz(struct secasvar *sav) 161 { 162 size_t size; 163 164 if (sav != NULL) { 165 int authsize; 166 IPSEC_ASSERT(sav->tdb_authalgxform != NULL, ("null xform")); 167 /*XXX not right for null algorithm--does it matter??*/ 168 authsize = AUTHSIZE(sav); 169 size = roundup(authsize, sizeof (u_int32_t)) + HDRSIZE(sav); 170 } else { 171 /* default guess */ 172 size = sizeof (struct ah) + sizeof (u_int32_t) + 16; 173 } 174 return size; 175 } 176 177 /* 178 * NB: public for use by esp_init. 179 */ 180 int 181 ah_init0(struct secasvar *sav, struct xformsw *xsp, struct cryptoini *cria) 182 { 183 struct auth_hash *thash; 184 int keylen; 185 186 thash = ah_algorithm_lookup(sav->alg_auth); 187 if (thash == NULL) { 188 DPRINTF(("%s: unsupported authentication algorithm %u\n", 189 __func__, sav->alg_auth)); 190 return EINVAL; 191 } 192 /* 193 * Verify the replay state block allocation is consistent with 194 * the protocol type. We check here so we can make assumptions 195 * later during protocol processing. 196 */ 197 /* NB: replay state is setup elsewhere (sigh) */ 198 if (((sav->flags&SADB_X_EXT_OLD) == 0) ^ (sav->replay != NULL)) { 199 DPRINTF(("%s: replay state block inconsistency, " 200 "%s algorithm %s replay state\n", __func__, 201 (sav->flags & SADB_X_EXT_OLD) ? "old" : "new", 202 sav->replay == NULL ? "without" : "with")); 203 return EINVAL; 204 } 205 if (sav->key_auth == NULL) { 206 DPRINTF(("%s: no authentication key for %s algorithm\n", 207 __func__, thash->name)); 208 return EINVAL; 209 } 210 keylen = _KEYLEN(sav->key_auth); 211 if (keylen != thash->keysize && thash->keysize != 0) { 212 DPRINTF(("%s: invalid keylength %d, algorithm %s requires " 213 "keysize %d\n", __func__, 214 keylen, thash->name, thash->keysize)); 215 return EINVAL; 216 } 217 218 sav->tdb_xform = xsp; 219 sav->tdb_authalgxform = thash; 220 221 /* Initialize crypto session. */ 222 bzero(cria, sizeof (*cria)); 223 cria->cri_alg = sav->tdb_authalgxform->type; 224 cria->cri_klen = _KEYBITS(sav->key_auth); 225 cria->cri_key = sav->key_auth->key_data; 226 cria->cri_mlen = AUTHSIZE(sav); 227 228 return 0; 229 } 230 231 /* 232 * ah_init() is called when an SPI is being set up. 233 */ 234 static int 235 ah_init(struct secasvar *sav, struct xformsw *xsp) 236 { 237 struct cryptoini cria; 238 int error; 239 240 error = ah_init0(sav, xsp, &cria); 241 return error ? error : 242 crypto_newsession(&sav->tdb_cryptoid, &cria, V_crypto_support); 243 } 244 245 /* 246 * Paranoia. 247 * 248 * NB: public for use by esp_zeroize (XXX). 249 */ 250 int 251 ah_zeroize(struct secasvar *sav) 252 { 253 int err; 254 255 if (sav->key_auth) 256 bzero(sav->key_auth->key_data, _KEYLEN(sav->key_auth)); 257 258 err = crypto_freesession(sav->tdb_cryptoid); 259 sav->tdb_cryptoid = 0; 260 sav->tdb_authalgxform = NULL; 261 sav->tdb_xform = NULL; 262 return err; 263 } 264 265 /* 266 * Massage IPv4/IPv6 headers for AH processing. 267 */ 268 static int 269 ah_massage_headers(struct mbuf **m0, int proto, int skip, int alg, int out) 270 { 271 struct mbuf *m = *m0; 272 unsigned char *ptr; 273 int off, count; 274 275 #ifdef INET 276 struct ip *ip; 277 #endif /* INET */ 278 279 #ifdef INET6 280 struct ip6_ext *ip6e; 281 struct ip6_hdr ip6; 282 int alloc, len, ad; 283 #endif /* INET6 */ 284 285 switch (proto) { 286 #ifdef INET 287 case AF_INET: 288 /* 289 * This is the least painful way of dealing with IPv4 header 290 * and option processing -- just make sure they're in 291 * contiguous memory. 292 */ 293 *m0 = m = m_pullup(m, skip); 294 if (m == NULL) { 295 DPRINTF(("%s: m_pullup failed\n", __func__)); 296 return ENOBUFS; 297 } 298 299 /* Fix the IP header */ 300 ip = mtod(m, struct ip *); 301 if (V_ah_cleartos) 302 ip->ip_tos = 0; 303 ip->ip_ttl = 0; 304 ip->ip_sum = 0; 305 306 /* 307 * On input, fix ip_len which has been byte-swapped 308 * at ip_input(). 309 */ 310 if (!out) { 311 ip->ip_len = htons(ip->ip_len + skip); 312 313 if (alg == CRYPTO_MD5_KPDK || alg == CRYPTO_SHA1_KPDK) 314 ip->ip_off = htons(ip->ip_off & IP_DF); 315 else 316 ip->ip_off = 0; 317 } else { 318 if (alg == CRYPTO_MD5_KPDK || alg == CRYPTO_SHA1_KPDK) 319 ip->ip_off = htons(ntohs(ip->ip_off) & IP_DF); 320 else 321 ip->ip_off = 0; 322 } 323 324 ptr = mtod(m, unsigned char *) + sizeof(struct ip); 325 326 /* IPv4 option processing */ 327 for (off = sizeof(struct ip); off < skip;) { 328 if (ptr[off] == IPOPT_EOL || ptr[off] == IPOPT_NOP || 329 off + 1 < skip) 330 ; 331 else { 332 DPRINTF(("%s: illegal IPv4 option length for " 333 "option %d\n", __func__, ptr[off])); 334 335 m_freem(m); 336 return EINVAL; 337 } 338 339 switch (ptr[off]) { 340 case IPOPT_EOL: 341 off = skip; /* End the loop. */ 342 break; 343 344 case IPOPT_NOP: 345 off++; 346 break; 347 348 case IPOPT_SECURITY: /* 0x82 */ 349 case 0x85: /* Extended security. */ 350 case 0x86: /* Commercial security. */ 351 case 0x94: /* Router alert */ 352 case 0x95: /* RFC1770 */ 353 /* Sanity check for option length. */ 354 if (ptr[off + 1] < 2) { 355 DPRINTF(("%s: illegal IPv4 option " 356 "length for option %d\n", 357 __func__, ptr[off])); 358 359 m_freem(m); 360 return EINVAL; 361 } 362 363 off += ptr[off + 1]; 364 break; 365 366 case IPOPT_LSRR: 367 case IPOPT_SSRR: 368 /* Sanity check for option length. */ 369 if (ptr[off + 1] < 2) { 370 DPRINTF(("%s: illegal IPv4 option " 371 "length for option %d\n", 372 __func__, ptr[off])); 373 374 m_freem(m); 375 return EINVAL; 376 } 377 378 /* 379 * On output, if we have either of the 380 * source routing options, we should 381 * swap the destination address of the 382 * IP header with the last address 383 * specified in the option, as that is 384 * what the destination's IP header 385 * will look like. 386 */ 387 if (out) 388 bcopy(ptr + off + ptr[off + 1] - 389 sizeof(struct in_addr), 390 &(ip->ip_dst), sizeof(struct in_addr)); 391 392 /* Fall through */ 393 default: 394 /* Sanity check for option length. */ 395 if (ptr[off + 1] < 2) { 396 DPRINTF(("%s: illegal IPv4 option " 397 "length for option %d\n", 398 __func__, ptr[off])); 399 m_freem(m); 400 return EINVAL; 401 } 402 403 /* Zeroize all other options. */ 404 count = ptr[off + 1]; 405 bcopy(ipseczeroes, ptr, count); 406 off += count; 407 break; 408 } 409 410 /* Sanity check. */ 411 if (off > skip) { 412 DPRINTF(("%s: malformed IPv4 options header\n", 413 __func__)); 414 415 m_freem(m); 416 return EINVAL; 417 } 418 } 419 420 break; 421 #endif /* INET */ 422 423 #ifdef INET6 424 case AF_INET6: /* Ugly... */ 425 /* Copy and "cook" the IPv6 header. */ 426 m_copydata(m, 0, sizeof(ip6), (caddr_t) &ip6); 427 428 /* We don't do IPv6 Jumbograms. */ 429 if (ip6.ip6_plen == 0) { 430 DPRINTF(("%s: unsupported IPv6 jumbogram\n", __func__)); 431 m_freem(m); 432 return EMSGSIZE; 433 } 434 435 ip6.ip6_flow = 0; 436 ip6.ip6_hlim = 0; 437 ip6.ip6_vfc &= ~IPV6_VERSION_MASK; 438 ip6.ip6_vfc |= IPV6_VERSION; 439 440 /* Scoped address handling. */ 441 if (IN6_IS_SCOPE_LINKLOCAL(&ip6.ip6_src)) 442 ip6.ip6_src.s6_addr16[1] = 0; 443 if (IN6_IS_SCOPE_LINKLOCAL(&ip6.ip6_dst)) 444 ip6.ip6_dst.s6_addr16[1] = 0; 445 446 /* Done with IPv6 header. */ 447 m_copyback(m, 0, sizeof(struct ip6_hdr), (caddr_t) &ip6); 448 449 /* Let's deal with the remaining headers (if any). */ 450 if (skip - sizeof(struct ip6_hdr) > 0) { 451 if (m->m_len <= skip) { 452 ptr = (unsigned char *) malloc( 453 skip - sizeof(struct ip6_hdr), 454 M_XDATA, M_NOWAIT); 455 if (ptr == NULL) { 456 DPRINTF(("%s: failed to allocate memory" 457 "for IPv6 headers\n",__func__)); 458 m_freem(m); 459 return ENOBUFS; 460 } 461 462 /* 463 * Copy all the protocol headers after 464 * the IPv6 header. 465 */ 466 m_copydata(m, sizeof(struct ip6_hdr), 467 skip - sizeof(struct ip6_hdr), ptr); 468 alloc = 1; 469 } else { 470 /* No need to allocate memory. */ 471 ptr = mtod(m, unsigned char *) + 472 sizeof(struct ip6_hdr); 473 alloc = 0; 474 } 475 } else 476 break; 477 478 off = ip6.ip6_nxt & 0xff; /* Next header type. */ 479 480 for (len = 0; len < skip - sizeof(struct ip6_hdr);) 481 switch (off) { 482 case IPPROTO_HOPOPTS: 483 case IPPROTO_DSTOPTS: 484 ip6e = (struct ip6_ext *) (ptr + len); 485 486 /* 487 * Process the mutable/immutable 488 * options -- borrows heavily from the 489 * KAME code. 490 */ 491 for (count = len + sizeof(struct ip6_ext); 492 count < len + ((ip6e->ip6e_len + 1) << 3);) { 493 if (ptr[count] == IP6OPT_PAD1) { 494 count++; 495 continue; /* Skip padding. */ 496 } 497 498 /* Sanity check. */ 499 if (count > len + 500 ((ip6e->ip6e_len + 1) << 3)) { 501 m_freem(m); 502 503 /* Free, if we allocated. */ 504 if (alloc) 505 free(ptr, M_XDATA); 506 return EINVAL; 507 } 508 509 ad = ptr[count + 1]; 510 511 /* If mutable option, zeroize. */ 512 if (ptr[count] & IP6OPT_MUTABLE) 513 bcopy(ipseczeroes, ptr + count, 514 ptr[count + 1]); 515 516 count += ad; 517 518 /* Sanity check. */ 519 if (count > 520 skip - sizeof(struct ip6_hdr)) { 521 m_freem(m); 522 523 /* Free, if we allocated. */ 524 if (alloc) 525 free(ptr, M_XDATA); 526 return EINVAL; 527 } 528 } 529 530 /* Advance. */ 531 len += ((ip6e->ip6e_len + 1) << 3); 532 off = ip6e->ip6e_nxt; 533 break; 534 535 case IPPROTO_ROUTING: 536 /* 537 * Always include routing headers in 538 * computation. 539 */ 540 ip6e = (struct ip6_ext *) (ptr + len); 541 len += ((ip6e->ip6e_len + 1) << 3); 542 off = ip6e->ip6e_nxt; 543 break; 544 545 default: 546 DPRINTF(("%s: unexpected IPv6 header type %d", 547 __func__, off)); 548 if (alloc) 549 free(ptr, M_XDATA); 550 m_freem(m); 551 return EINVAL; 552 } 553 554 /* Copyback and free, if we allocated. */ 555 if (alloc) { 556 m_copyback(m, sizeof(struct ip6_hdr), 557 skip - sizeof(struct ip6_hdr), ptr); 558 free(ptr, M_XDATA); 559 } 560 561 break; 562 #endif /* INET6 */ 563 } 564 565 return 0; 566 } 567 568 /* 569 * ah_input() gets called to verify that an input packet 570 * passes authentication. 571 */ 572 static int 573 ah_input(struct mbuf *m, struct secasvar *sav, int skip, int protoff) 574 { 575 struct auth_hash *ahx; 576 struct tdb_ident *tdbi; 577 struct tdb_crypto *tc; 578 struct m_tag *mtag; 579 struct newah *ah; 580 int hl, rplen, authsize; 581 582 struct cryptodesc *crda; 583 struct cryptop *crp; 584 585 IPSEC_ASSERT(sav != NULL, ("null SA")); 586 IPSEC_ASSERT(sav->key_auth != NULL, ("null authentication key")); 587 IPSEC_ASSERT(sav->tdb_authalgxform != NULL, 588 ("null authentication xform")); 589 590 /* Figure out header size. */ 591 rplen = HDRSIZE(sav); 592 593 /* XXX don't pullup, just copy header */ 594 IP6_EXTHDR_GET(ah, struct newah *, m, skip, rplen); 595 if (ah == NULL) { 596 DPRINTF(("ah_input: cannot pullup header\n")); 597 V_ahstat.ahs_hdrops++; /*XXX*/ 598 m_freem(m); 599 return ENOBUFS; 600 } 601 602 /* Check replay window, if applicable. */ 603 if (sav->replay && !ipsec_chkreplay(ntohl(ah->ah_seq), sav)) { 604 V_ahstat.ahs_replay++; 605 DPRINTF(("%s: packet replay failure: %s\n", __func__, 606 ipsec_logsastr(sav))); 607 m_freem(m); 608 return ENOBUFS; 609 } 610 611 /* Verify AH header length. */ 612 hl = ah->ah_len * sizeof (u_int32_t); 613 ahx = sav->tdb_authalgxform; 614 authsize = AUTHSIZE(sav); 615 if (hl != authsize + rplen - sizeof (struct ah)) { 616 DPRINTF(("%s: bad authenticator length %u (expecting %lu)" 617 " for packet in SA %s/%08lx\n", __func__, 618 hl, (u_long) (authsize + rplen - sizeof (struct ah)), 619 ipsec_address(&sav->sah->saidx.dst), 620 (u_long) ntohl(sav->spi))); 621 V_ahstat.ahs_badauthl++; 622 m_freem(m); 623 return EACCES; 624 } 625 V_ahstat.ahs_ibytes += m->m_pkthdr.len - skip - hl; 626 627 /* Get crypto descriptors. */ 628 crp = crypto_getreq(1); 629 if (crp == NULL) { 630 DPRINTF(("%s: failed to acquire crypto descriptor\n",__func__)); 631 V_ahstat.ahs_crypto++; 632 m_freem(m); 633 return ENOBUFS; 634 } 635 636 crda = crp->crp_desc; 637 IPSEC_ASSERT(crda != NULL, ("null crypto descriptor")); 638 639 crda->crd_skip = 0; 640 crda->crd_len = m->m_pkthdr.len; 641 crda->crd_inject = skip + rplen; 642 643 /* Authentication operation. */ 644 crda->crd_alg = ahx->type; 645 crda->crd_klen = _KEYBITS(sav->key_auth); 646 crda->crd_key = sav->key_auth->key_data; 647 648 /* Find out if we've already done crypto. */ 649 for (mtag = m_tag_find(m, PACKET_TAG_IPSEC_IN_CRYPTO_DONE, NULL); 650 mtag != NULL; 651 mtag = m_tag_find(m, PACKET_TAG_IPSEC_IN_CRYPTO_DONE, mtag)) { 652 tdbi = (struct tdb_ident *) (mtag + 1); 653 if (tdbi->proto == sav->sah->saidx.proto && 654 tdbi->spi == sav->spi && 655 !bcmp(&tdbi->dst, &sav->sah->saidx.dst, 656 sizeof (union sockaddr_union))) 657 break; 658 } 659 660 /* Allocate IPsec-specific opaque crypto info. */ 661 if (mtag == NULL) { 662 tc = (struct tdb_crypto *) malloc(sizeof (struct tdb_crypto) + 663 skip + rplen + authsize, M_XDATA, M_NOWAIT|M_ZERO); 664 } else { 665 /* Hash verification has already been done successfully. */ 666 tc = (struct tdb_crypto *) malloc(sizeof (struct tdb_crypto), 667 M_XDATA, M_NOWAIT|M_ZERO); 668 } 669 if (tc == NULL) { 670 DPRINTF(("%s: failed to allocate tdb_crypto\n", __func__)); 671 V_ahstat.ahs_crypto++; 672 crypto_freereq(crp); 673 m_freem(m); 674 return ENOBUFS; 675 } 676 677 /* Only save information if crypto processing is needed. */ 678 if (mtag == NULL) { 679 int error; 680 681 /* 682 * Save the authenticator, the skipped portion of the packet, 683 * and the AH header. 684 */ 685 m_copydata(m, 0, skip + rplen + authsize, (caddr_t)(tc+1)); 686 687 /* Zeroize the authenticator on the packet. */ 688 m_copyback(m, skip + rplen, authsize, ipseczeroes); 689 690 /* "Massage" the packet headers for crypto processing. */ 691 error = ah_massage_headers(&m, sav->sah->saidx.dst.sa.sa_family, 692 skip, ahx->type, 0); 693 if (error != 0) { 694 /* NB: mbuf is free'd by ah_massage_headers */ 695 V_ahstat.ahs_hdrops++; 696 free(tc, M_XDATA); 697 crypto_freereq(crp); 698 return error; 699 } 700 } 701 702 /* Crypto operation descriptor. */ 703 crp->crp_ilen = m->m_pkthdr.len; /* Total input length. */ 704 crp->crp_flags = CRYPTO_F_IMBUF | CRYPTO_F_CBIFSYNC; 705 crp->crp_buf = (caddr_t) m; 706 crp->crp_callback = ah_input_cb; 707 crp->crp_sid = sav->tdb_cryptoid; 708 crp->crp_opaque = (caddr_t) tc; 709 710 /* These are passed as-is to the callback. */ 711 tc->tc_spi = sav->spi; 712 tc->tc_dst = sav->sah->saidx.dst; 713 tc->tc_proto = sav->sah->saidx.proto; 714 tc->tc_nxt = ah->ah_nxt; 715 tc->tc_protoff = protoff; 716 tc->tc_skip = skip; 717 tc->tc_ptr = (caddr_t) mtag; /* Save the mtag we've identified. */ 718 719 if (mtag == NULL) 720 return crypto_dispatch(crp); 721 else 722 return ah_input_cb(crp); 723 } 724 725 #ifdef INET6 726 #define IPSEC_COMMON_INPUT_CB(m, sav, skip, protoff, mtag) do { \ 727 if (saidx->dst.sa.sa_family == AF_INET6) { \ 728 error = ipsec6_common_input_cb(m, sav, skip, protoff, mtag); \ 729 } else { \ 730 error = ipsec4_common_input_cb(m, sav, skip, protoff, mtag); \ 731 } \ 732 } while (0) 733 #else 734 #define IPSEC_COMMON_INPUT_CB(m, sav, skip, protoff, mtag) \ 735 (error = ipsec4_common_input_cb(m, sav, skip, protoff, mtag)) 736 #endif 737 738 /* 739 * AH input callback from the crypto driver. 740 */ 741 static int 742 ah_input_cb(struct cryptop *crp) 743 { 744 int rplen, error, skip, protoff; 745 unsigned char calc[AH_ALEN_MAX]; 746 struct mbuf *m; 747 struct cryptodesc *crd; 748 struct auth_hash *ahx; 749 struct tdb_crypto *tc; 750 struct m_tag *mtag; 751 struct secasvar *sav; 752 struct secasindex *saidx; 753 u_int8_t nxt; 754 caddr_t ptr; 755 int authsize; 756 757 crd = crp->crp_desc; 758 759 tc = (struct tdb_crypto *) crp->crp_opaque; 760 IPSEC_ASSERT(tc != NULL, ("null opaque crypto data area!")); 761 skip = tc->tc_skip; 762 nxt = tc->tc_nxt; 763 protoff = tc->tc_protoff; 764 mtag = (struct m_tag *) tc->tc_ptr; 765 m = (struct mbuf *) crp->crp_buf; 766 767 sav = KEY_ALLOCSA(&tc->tc_dst, tc->tc_proto, tc->tc_spi); 768 if (sav == NULL) { 769 V_ahstat.ahs_notdb++; 770 DPRINTF(("%s: SA expired while in crypto\n", __func__)); 771 error = ENOBUFS; /*XXX*/ 772 goto bad; 773 } 774 775 saidx = &sav->sah->saidx; 776 IPSEC_ASSERT(saidx->dst.sa.sa_family == AF_INET || 777 saidx->dst.sa.sa_family == AF_INET6, 778 ("unexpected protocol family %u", saidx->dst.sa.sa_family)); 779 780 ahx = (struct auth_hash *) sav->tdb_authalgxform; 781 782 /* Check for crypto errors. */ 783 if (crp->crp_etype) { 784 if (sav->tdb_cryptoid != 0) 785 sav->tdb_cryptoid = crp->crp_sid; 786 787 if (crp->crp_etype == EAGAIN) { 788 error = crypto_dispatch(crp); 789 return error; 790 } 791 792 V_ahstat.ahs_noxform++; 793 DPRINTF(("%s: crypto error %d\n", __func__, crp->crp_etype)); 794 error = crp->crp_etype; 795 goto bad; 796 } else { 797 V_ahstat.ahs_hist[sav->alg_auth]++; 798 crypto_freereq(crp); /* No longer needed. */ 799 crp = NULL; 800 } 801 802 /* Shouldn't happen... */ 803 if (m == NULL) { 804 V_ahstat.ahs_crypto++; 805 DPRINTF(("%s: bogus returned buffer from crypto\n", __func__)); 806 error = EINVAL; 807 goto bad; 808 } 809 810 /* Figure out header size. */ 811 rplen = HDRSIZE(sav); 812 authsize = AUTHSIZE(sav); 813 814 /* Copy authenticator off the packet. */ 815 m_copydata(m, skip + rplen, authsize, calc); 816 817 /* 818 * If we have an mtag, we don't need to verify the authenticator -- 819 * it has been verified by an IPsec-aware NIC. 820 */ 821 if (mtag == NULL) { 822 ptr = (caddr_t) (tc + 1); 823 824 /* Verify authenticator. */ 825 if (bcmp(ptr + skip + rplen, calc, authsize)) { 826 DPRINTF(("%s: authentication hash mismatch for packet " 827 "in SA %s/%08lx\n", __func__, 828 ipsec_address(&saidx->dst), 829 (u_long) ntohl(sav->spi))); 830 V_ahstat.ahs_badauth++; 831 error = EACCES; 832 goto bad; 833 } 834 835 /* Fix the Next Protocol field. */ 836 ((u_int8_t *) ptr)[protoff] = nxt; 837 838 /* Copyback the saved (uncooked) network headers. */ 839 m_copyback(m, 0, skip, ptr); 840 } else { 841 /* Fix the Next Protocol field. */ 842 m_copyback(m, protoff, sizeof(u_int8_t), &nxt); 843 } 844 845 free(tc, M_XDATA), tc = NULL; /* No longer needed */ 846 847 /* 848 * Header is now authenticated. 849 */ 850 m->m_flags |= M_AUTHIPHDR|M_AUTHIPDGM; 851 852 /* 853 * Update replay sequence number, if appropriate. 854 */ 855 if (sav->replay) { 856 u_int32_t seq; 857 858 m_copydata(m, skip + offsetof(struct newah, ah_seq), 859 sizeof (seq), (caddr_t) &seq); 860 if (ipsec_updatereplay(ntohl(seq), sav)) { 861 V_ahstat.ahs_replay++; 862 error = ENOBUFS; /*XXX as above*/ 863 goto bad; 864 } 865 } 866 867 /* 868 * Remove the AH header and authenticator from the mbuf. 869 */ 870 error = m_striphdr(m, skip, rplen + authsize); 871 if (error) { 872 DPRINTF(("%s: mangled mbuf chain for SA %s/%08lx\n", __func__, 873 ipsec_address(&saidx->dst), (u_long) ntohl(sav->spi))); 874 875 V_ahstat.ahs_hdrops++; 876 goto bad; 877 } 878 879 IPSEC_COMMON_INPUT_CB(m, sav, skip, protoff, mtag); 880 881 KEY_FREESAV(&sav); 882 return error; 883 bad: 884 if (sav) 885 KEY_FREESAV(&sav); 886 if (m != NULL) 887 m_freem(m); 888 if (tc != NULL) 889 free(tc, M_XDATA); 890 if (crp != NULL) 891 crypto_freereq(crp); 892 return error; 893 } 894 895 /* 896 * AH output routine, called by ipsec[46]_process_packet(). 897 */ 898 static int 899 ah_output( 900 struct mbuf *m, 901 struct ipsecrequest *isr, 902 struct mbuf **mp, 903 int skip, 904 int protoff) 905 { 906 struct secasvar *sav; 907 struct auth_hash *ahx; 908 struct cryptodesc *crda; 909 struct tdb_crypto *tc; 910 struct mbuf *mi; 911 struct cryptop *crp; 912 u_int16_t iplen; 913 int error, rplen, authsize, maxpacketsize, roff; 914 u_int8_t prot; 915 struct newah *ah; 916 917 sav = isr->sav; 918 IPSEC_ASSERT(sav != NULL, ("null SA")); 919 ahx = sav->tdb_authalgxform; 920 IPSEC_ASSERT(ahx != NULL, ("null authentication xform")); 921 922 V_ahstat.ahs_output++; 923 924 /* Figure out header size. */ 925 rplen = HDRSIZE(sav); 926 927 /* Check for maximum packet size violations. */ 928 switch (sav->sah->saidx.dst.sa.sa_family) { 929 #ifdef INET 930 case AF_INET: 931 maxpacketsize = IP_MAXPACKET; 932 break; 933 #endif /* INET */ 934 #ifdef INET6 935 case AF_INET6: 936 maxpacketsize = IPV6_MAXPACKET; 937 break; 938 #endif /* INET6 */ 939 default: 940 DPRINTF(("%s: unknown/unsupported protocol family %u, " 941 "SA %s/%08lx\n", __func__, 942 sav->sah->saidx.dst.sa.sa_family, 943 ipsec_address(&sav->sah->saidx.dst), 944 (u_long) ntohl(sav->spi))); 945 V_ahstat.ahs_nopf++; 946 error = EPFNOSUPPORT; 947 goto bad; 948 } 949 authsize = AUTHSIZE(sav); 950 if (rplen + authsize + m->m_pkthdr.len > maxpacketsize) { 951 DPRINTF(("%s: packet in SA %s/%08lx got too big " 952 "(len %u, max len %u)\n", __func__, 953 ipsec_address(&sav->sah->saidx.dst), 954 (u_long) ntohl(sav->spi), 955 rplen + authsize + m->m_pkthdr.len, maxpacketsize)); 956 V_ahstat.ahs_toobig++; 957 error = EMSGSIZE; 958 goto bad; 959 } 960 961 /* Update the counters. */ 962 V_ahstat.ahs_obytes += m->m_pkthdr.len - skip; 963 964 m = m_unshare(m, M_NOWAIT); 965 if (m == NULL) { 966 DPRINTF(("%s: cannot clone mbuf chain, SA %s/%08lx\n", __func__, 967 ipsec_address(&sav->sah->saidx.dst), 968 (u_long) ntohl(sav->spi))); 969 V_ahstat.ahs_hdrops++; 970 error = ENOBUFS; 971 goto bad; 972 } 973 974 /* Inject AH header. */ 975 mi = m_makespace(m, skip, rplen + authsize, &roff); 976 if (mi == NULL) { 977 DPRINTF(("%s: failed to inject %u byte AH header for SA " 978 "%s/%08lx\n", __func__, 979 rplen + authsize, 980 ipsec_address(&sav->sah->saidx.dst), 981 (u_long) ntohl(sav->spi))); 982 V_ahstat.ahs_hdrops++; /*XXX differs from openbsd */ 983 error = ENOBUFS; 984 goto bad; 985 } 986 987 /* 988 * The AH header is guaranteed by m_makespace() to be in 989 * contiguous memory, at roff bytes offset into the returned mbuf. 990 */ 991 ah = (struct newah *)(mtod(mi, caddr_t) + roff); 992 993 /* Initialize the AH header. */ 994 m_copydata(m, protoff, sizeof(u_int8_t), (caddr_t) &ah->ah_nxt); 995 ah->ah_len = (rplen + authsize - sizeof(struct ah)) / sizeof(u_int32_t); 996 ah->ah_reserve = 0; 997 ah->ah_spi = sav->spi; 998 999 /* Zeroize authenticator. */ 1000 m_copyback(m, skip + rplen, authsize, ipseczeroes); 1001 1002 /* Insert packet replay counter, as requested. */ 1003 if (sav->replay) { 1004 if (sav->replay->count == ~0 && 1005 (sav->flags & SADB_X_EXT_CYCSEQ) == 0) { 1006 DPRINTF(("%s: replay counter wrapped for SA %s/%08lx\n", 1007 __func__, 1008 ipsec_address(&sav->sah->saidx.dst), 1009 (u_long) ntohl(sav->spi))); 1010 V_ahstat.ahs_wrap++; 1011 error = EINVAL; 1012 goto bad; 1013 } 1014 #ifdef REGRESSION 1015 /* Emulate replay attack when ipsec_replay is TRUE. */ 1016 if (!V_ipsec_replay) 1017 #endif 1018 sav->replay->count++; 1019 ah->ah_seq = htonl(sav->replay->count); 1020 } 1021 1022 /* Get crypto descriptors. */ 1023 crp = crypto_getreq(1); 1024 if (crp == NULL) { 1025 DPRINTF(("%s: failed to acquire crypto descriptors\n", 1026 __func__)); 1027 V_ahstat.ahs_crypto++; 1028 error = ENOBUFS; 1029 goto bad; 1030 } 1031 1032 crda = crp->crp_desc; 1033 1034 crda->crd_skip = 0; 1035 crda->crd_inject = skip + rplen; 1036 crda->crd_len = m->m_pkthdr.len; 1037 1038 /* Authentication operation. */ 1039 crda->crd_alg = ahx->type; 1040 crda->crd_key = sav->key_auth->key_data; 1041 crda->crd_klen = _KEYBITS(sav->key_auth); 1042 1043 /* Allocate IPsec-specific opaque crypto info. */ 1044 tc = (struct tdb_crypto *) malloc( 1045 sizeof(struct tdb_crypto) + skip, M_XDATA, M_NOWAIT|M_ZERO); 1046 if (tc == NULL) { 1047 crypto_freereq(crp); 1048 DPRINTF(("%s: failed to allocate tdb_crypto\n", __func__)); 1049 V_ahstat.ahs_crypto++; 1050 error = ENOBUFS; 1051 goto bad; 1052 } 1053 1054 /* Save the skipped portion of the packet. */ 1055 m_copydata(m, 0, skip, (caddr_t) (tc + 1)); 1056 1057 /* 1058 * Fix IP header length on the header used for 1059 * authentication. We don't need to fix the original 1060 * header length as it will be fixed by our caller. 1061 */ 1062 switch (sav->sah->saidx.dst.sa.sa_family) { 1063 #ifdef INET 1064 case AF_INET: 1065 bcopy(((caddr_t)(tc + 1)) + 1066 offsetof(struct ip, ip_len), 1067 (caddr_t) &iplen, sizeof(u_int16_t)); 1068 iplen = htons(ntohs(iplen) + rplen + authsize); 1069 m_copyback(m, offsetof(struct ip, ip_len), 1070 sizeof(u_int16_t), (caddr_t) &iplen); 1071 break; 1072 #endif /* INET */ 1073 1074 #ifdef INET6 1075 case AF_INET6: 1076 bcopy(((caddr_t)(tc + 1)) + 1077 offsetof(struct ip6_hdr, ip6_plen), 1078 (caddr_t) &iplen, sizeof(u_int16_t)); 1079 iplen = htons(ntohs(iplen) + rplen + authsize); 1080 m_copyback(m, offsetof(struct ip6_hdr, ip6_plen), 1081 sizeof(u_int16_t), (caddr_t) &iplen); 1082 break; 1083 #endif /* INET6 */ 1084 } 1085 1086 /* Fix the Next Header field in saved header. */ 1087 ((u_int8_t *) (tc + 1))[protoff] = IPPROTO_AH; 1088 1089 /* Update the Next Protocol field in the IP header. */ 1090 prot = IPPROTO_AH; 1091 m_copyback(m, protoff, sizeof(u_int8_t), (caddr_t) &prot); 1092 1093 /* "Massage" the packet headers for crypto processing. */ 1094 error = ah_massage_headers(&m, sav->sah->saidx.dst.sa.sa_family, 1095 skip, ahx->type, 1); 1096 if (error != 0) { 1097 m = NULL; /* mbuf was free'd by ah_massage_headers. */ 1098 free(tc, M_XDATA); 1099 crypto_freereq(crp); 1100 goto bad; 1101 } 1102 1103 /* Crypto operation descriptor. */ 1104 crp->crp_ilen = m->m_pkthdr.len; /* Total input length. */ 1105 crp->crp_flags = CRYPTO_F_IMBUF | CRYPTO_F_CBIFSYNC; 1106 crp->crp_buf = (caddr_t) m; 1107 crp->crp_callback = ah_output_cb; 1108 crp->crp_sid = sav->tdb_cryptoid; 1109 crp->crp_opaque = (caddr_t) tc; 1110 1111 /* These are passed as-is to the callback. */ 1112 tc->tc_isr = isr; 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 int err; 1139 1140 tc = (struct tdb_crypto *) crp->crp_opaque; 1141 IPSEC_ASSERT(tc != NULL, ("null opaque data area!")); 1142 skip = tc->tc_skip; 1143 protoff = tc->tc_protoff; 1144 ptr = (caddr_t) (tc + 1); 1145 m = (struct mbuf *) crp->crp_buf; 1146 1147 isr = tc->tc_isr; 1148 IPSECREQUEST_LOCK(isr); 1149 sav = KEY_ALLOCSA(&tc->tc_dst, tc->tc_proto, tc->tc_spi); 1150 if (sav == NULL) { 1151 V_ahstat.ahs_notdb++; 1152 DPRINTF(("%s: SA expired while in crypto\n", __func__)); 1153 error = ENOBUFS; /*XXX*/ 1154 goto bad; 1155 } 1156 IPSEC_ASSERT(isr->sav == sav, ("SA changed\n")); 1157 1158 /* Check for crypto errors. */ 1159 if (crp->crp_etype) { 1160 if (sav->tdb_cryptoid != 0) 1161 sav->tdb_cryptoid = crp->crp_sid; 1162 1163 if (crp->crp_etype == EAGAIN) { 1164 KEY_FREESAV(&sav); 1165 IPSECREQUEST_UNLOCK(isr); 1166 error = crypto_dispatch(crp); 1167 return error; 1168 } 1169 1170 V_ahstat.ahs_noxform++; 1171 DPRINTF(("%s: crypto error %d\n", __func__, crp->crp_etype)); 1172 error = crp->crp_etype; 1173 goto bad; 1174 } 1175 1176 /* Shouldn't happen... */ 1177 if (m == NULL) { 1178 V_ahstat.ahs_crypto++; 1179 DPRINTF(("%s: bogus returned buffer from crypto\n", __func__)); 1180 error = EINVAL; 1181 goto bad; 1182 } 1183 V_ahstat.ahs_hist[sav->alg_auth]++; 1184 1185 /* 1186 * Copy original headers (with the new protocol number) back 1187 * in place. 1188 */ 1189 m_copyback(m, 0, skip, ptr); 1190 1191 /* No longer needed. */ 1192 free(tc, M_XDATA); 1193 crypto_freereq(crp); 1194 1195 #ifdef REGRESSION 1196 /* Emulate man-in-the-middle attack when ipsec_integrity is TRUE. */ 1197 if (V_ipsec_integrity) { 1198 int alen; 1199 1200 /* 1201 * Corrupt HMAC if we want to test integrity verification of 1202 * the other side. 1203 */ 1204 alen = AUTHSIZE(sav); 1205 m_copyback(m, m->m_pkthdr.len - alen, alen, ipseczeroes); 1206 } 1207 #endif 1208 1209 /* NB: m is reclaimed by ipsec_process_done. */ 1210 err = ipsec_process_done(m, isr); 1211 KEY_FREESAV(&sav); 1212 IPSECREQUEST_UNLOCK(isr); 1213 return err; 1214 bad: 1215 if (sav) 1216 KEY_FREESAV(&sav); 1217 IPSECREQUEST_UNLOCK(isr); 1218 if (m) 1219 m_freem(m); 1220 free(tc, M_XDATA); 1221 crypto_freereq(crp); 1222 return error; 1223 } 1224 1225 static struct xformsw ah_xformsw = { 1226 XF_AH, XFT_AUTH, "IPsec AH", 1227 ah_init, ah_zeroize, ah_input, ah_output, 1228 }; 1229 1230 static void 1231 ah_attach(void) 1232 { 1233 1234 xform_register(&ah_xformsw); 1235 } 1236 1237 SYSINIT(ah_xform_init, SI_SUB_PROTO_DOMAIN, SI_ORDER_MIDDLE, ah_attach, NULL); 1238