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/lock.h> 49 #include <sys/mutex.h> 50 #include <sys/sysctl.h> 51 52 #include <net/if.h> 53 #include <net/vnet.h> 54 55 #include <netinet/in.h> 56 #include <netinet/in_systm.h> 57 #include <netinet/ip.h> 58 #include <netinet/ip_ecn.h> 59 #include <netinet/ip6.h> 60 61 #include <netipsec/ipsec.h> 62 #include <netipsec/ah.h> 63 #include <netipsec/ah_var.h> 64 #include <netipsec/xform.h> 65 66 #ifdef INET6 67 #include <netinet6/ip6_var.h> 68 #include <netipsec/ipsec6.h> 69 #include <netinet6/ip6_ecn.h> 70 #endif 71 72 #include <netipsec/key.h> 73 #include <netipsec/key_debug.h> 74 75 #include <opencrypto/cryptodev.h> 76 77 /* 78 * Return header size in bytes. The old protocol did not support 79 * the replay counter; the new protocol always includes the counter. 80 */ 81 #define HDRSIZE(sav) \ 82 (((sav)->flags & SADB_X_EXT_OLD) ? \ 83 sizeof (struct ah) : sizeof (struct ah) + sizeof (u_int32_t)) 84 /* 85 * Return authenticator size in bytes, based on a field in the 86 * algorithm descriptor. 87 */ 88 #define AUTHSIZE(sav) ((sav->flags & SADB_X_EXT_OLD) ? 16 : \ 89 xform_ah_authsize((sav)->tdb_authalgxform)) 90 91 VNET_DEFINE(int, ah_enable) = 1; /* control flow of packets with AH */ 92 VNET_DEFINE(int, ah_cleartos) = 1; /* clear ip_tos when doing AH calc */ 93 VNET_PCPUSTAT_DEFINE(struct ahstat, ahstat); 94 VNET_PCPUSTAT_SYSINIT(ahstat); 95 96 #ifdef VIMAGE 97 VNET_PCPUSTAT_SYSUNINIT(ahstat); 98 #endif /* VIMAGE */ 99 100 #ifdef INET 101 SYSCTL_DECL(_net_inet_ah); 102 SYSCTL_INT(_net_inet_ah, OID_AUTO, ah_enable, 103 CTLFLAG_VNET | CTLFLAG_RW, &VNET_NAME(ah_enable), 0, ""); 104 SYSCTL_INT(_net_inet_ah, OID_AUTO, ah_cleartos, 105 CTLFLAG_VNET | CTLFLAG_RW, &VNET_NAME(ah_cleartos), 0, ""); 106 SYSCTL_VNET_PCPUSTAT(_net_inet_ah, IPSECCTL_STATS, stats, struct ahstat, 107 ahstat, "AH statistics (struct ahstat, netipsec/ah_var.h)"); 108 #endif 109 110 static unsigned char ipseczeroes[256]; /* larger than an ip6 extension hdr */ 111 112 static int ah_input_cb(struct cryptop*); 113 static int ah_output_cb(struct cryptop*); 114 115 int 116 xform_ah_authsize(const struct auth_hash *esph) 117 { 118 int alen; 119 120 if (esph == NULL) 121 return 0; 122 123 switch (esph->type) { 124 case CRYPTO_SHA2_256_HMAC: 125 case CRYPTO_SHA2_384_HMAC: 126 case CRYPTO_SHA2_512_HMAC: 127 alen = esph->hashsize / 2; /* RFC4868 2.3 */ 128 break; 129 130 case CRYPTO_AES_128_NIST_GMAC: 131 case CRYPTO_AES_192_NIST_GMAC: 132 case CRYPTO_AES_256_NIST_GMAC: 133 alen = esph->hashsize; 134 break; 135 136 default: 137 alen = AH_HMAC_HASHLEN; 138 break; 139 } 140 141 return alen; 142 } 143 144 size_t 145 ah_hdrsiz(struct secasvar *sav) 146 { 147 size_t size; 148 149 if (sav != NULL) { 150 int authsize; 151 IPSEC_ASSERT(sav->tdb_authalgxform != NULL, ("null xform")); 152 /*XXX not right for null algorithm--does it matter??*/ 153 authsize = AUTHSIZE(sav); 154 size = roundup(authsize, sizeof (u_int32_t)) + HDRSIZE(sav); 155 } else { 156 /* default guess */ 157 size = sizeof (struct ah) + sizeof (u_int32_t) + 16; 158 } 159 return size; 160 } 161 162 /* 163 * NB: public for use by esp_init. 164 */ 165 int 166 ah_init0(struct secasvar *sav, struct xformsw *xsp, struct cryptoini *cria) 167 { 168 const struct auth_hash *thash; 169 int keylen; 170 171 thash = auth_algorithm_lookup(sav->alg_auth); 172 if (thash == NULL) { 173 DPRINTF(("%s: unsupported authentication algorithm %u\n", 174 __func__, sav->alg_auth)); 175 return EINVAL; 176 } 177 /* 178 * Verify the replay state block allocation is consistent with 179 * the protocol type. We check here so we can make assumptions 180 * later during protocol processing. 181 */ 182 /* NB: replay state is setup elsewhere (sigh) */ 183 if (((sav->flags&SADB_X_EXT_OLD) == 0) ^ (sav->replay != NULL)) { 184 DPRINTF(("%s: replay state block inconsistency, " 185 "%s algorithm %s replay state\n", __func__, 186 (sav->flags & SADB_X_EXT_OLD) ? "old" : "new", 187 sav->replay == NULL ? "without" : "with")); 188 return EINVAL; 189 } 190 if (sav->key_auth == NULL) { 191 DPRINTF(("%s: no authentication key for %s algorithm\n", 192 __func__, thash->name)); 193 return EINVAL; 194 } 195 keylen = _KEYLEN(sav->key_auth); 196 if (keylen > thash->keysize && thash->keysize != 0) { 197 DPRINTF(("%s: invalid keylength %d, algorithm %s requires " 198 "keysize less than %d\n", __func__, 199 keylen, thash->name, thash->keysize)); 200 return EINVAL; 201 } 202 203 sav->tdb_xform = xsp; 204 sav->tdb_authalgxform = thash; 205 206 /* Initialize crypto session. */ 207 bzero(cria, sizeof (*cria)); 208 cria->cri_alg = sav->tdb_authalgxform->type; 209 cria->cri_klen = _KEYBITS(sav->key_auth); 210 cria->cri_key = sav->key_auth->key_data; 211 cria->cri_mlen = AUTHSIZE(sav); 212 213 return 0; 214 } 215 216 /* 217 * ah_init() is called when an SPI is being set up. 218 */ 219 static int 220 ah_init(struct secasvar *sav, struct xformsw *xsp) 221 { 222 struct cryptoini cria; 223 int error; 224 225 error = ah_init0(sav, xsp, &cria); 226 return error ? error : 227 crypto_newsession(&sav->tdb_cryptoid, &cria, V_crypto_support); 228 } 229 230 /* 231 * Paranoia. 232 * 233 * NB: public for use by esp_zeroize (XXX). 234 */ 235 int 236 ah_zeroize(struct secasvar *sav) 237 { 238 int err; 239 240 if (sav->key_auth) 241 bzero(sav->key_auth->key_data, _KEYLEN(sav->key_auth)); 242 243 err = crypto_freesession(sav->tdb_cryptoid); 244 sav->tdb_cryptoid = 0; 245 sav->tdb_authalgxform = NULL; 246 sav->tdb_xform = NULL; 247 return err; 248 } 249 250 /* 251 * Massage IPv4/IPv6 headers for AH processing. 252 */ 253 static int 254 ah_massage_headers(struct mbuf **m0, int proto, int skip, int alg, int out) 255 { 256 struct mbuf *m = *m0; 257 unsigned char *ptr; 258 int off, count; 259 260 #ifdef INET 261 struct ip *ip; 262 #endif /* INET */ 263 264 #ifdef INET6 265 struct ip6_ext *ip6e; 266 struct ip6_hdr ip6; 267 int alloc, len, ad; 268 #endif /* INET6 */ 269 270 switch (proto) { 271 #ifdef INET 272 case AF_INET: 273 /* 274 * This is the least painful way of dealing with IPv4 header 275 * and option processing -- just make sure they're in 276 * contiguous memory. 277 */ 278 *m0 = m = m_pullup(m, skip); 279 if (m == NULL) { 280 DPRINTF(("%s: m_pullup failed\n", __func__)); 281 return ENOBUFS; 282 } 283 284 /* Fix the IP header */ 285 ip = mtod(m, struct ip *); 286 if (V_ah_cleartos) 287 ip->ip_tos = 0; 288 ip->ip_ttl = 0; 289 ip->ip_sum = 0; 290 291 if (alg == CRYPTO_MD5_KPDK || alg == CRYPTO_SHA1_KPDK) 292 ip->ip_off &= htons(IP_DF); 293 else 294 ip->ip_off = htons(0); 295 296 ptr = mtod(m, unsigned char *) + sizeof(struct ip); 297 298 /* IPv4 option processing */ 299 for (off = sizeof(struct ip); off < skip;) { 300 if (ptr[off] == IPOPT_EOL || ptr[off] == IPOPT_NOP || 301 off + 1 < skip) 302 ; 303 else { 304 DPRINTF(("%s: illegal IPv4 option length for " 305 "option %d\n", __func__, ptr[off])); 306 307 m_freem(m); 308 return EINVAL; 309 } 310 311 switch (ptr[off]) { 312 case IPOPT_EOL: 313 off = skip; /* End the loop. */ 314 break; 315 316 case IPOPT_NOP: 317 off++; 318 break; 319 320 case IPOPT_SECURITY: /* 0x82 */ 321 case 0x85: /* Extended security. */ 322 case 0x86: /* Commercial security. */ 323 case 0x94: /* Router alert */ 324 case 0x95: /* RFC1770 */ 325 /* Sanity check for option length. */ 326 if (ptr[off + 1] < 2) { 327 DPRINTF(("%s: illegal IPv4 option " 328 "length for option %d\n", 329 __func__, ptr[off])); 330 331 m_freem(m); 332 return EINVAL; 333 } 334 335 off += ptr[off + 1]; 336 break; 337 338 case IPOPT_LSRR: 339 case IPOPT_SSRR: 340 /* Sanity check for option length. */ 341 if (ptr[off + 1] < 2) { 342 DPRINTF(("%s: illegal IPv4 option " 343 "length for option %d\n", 344 __func__, ptr[off])); 345 346 m_freem(m); 347 return EINVAL; 348 } 349 350 /* 351 * On output, if we have either of the 352 * source routing options, we should 353 * swap the destination address of the 354 * IP header with the last address 355 * specified in the option, as that is 356 * what the destination's IP header 357 * will look like. 358 */ 359 if (out) 360 bcopy(ptr + off + ptr[off + 1] - 361 sizeof(struct in_addr), 362 &(ip->ip_dst), sizeof(struct in_addr)); 363 364 /* Fall through */ 365 default: 366 /* Sanity check for option length. */ 367 if (ptr[off + 1] < 2) { 368 DPRINTF(("%s: illegal IPv4 option " 369 "length for option %d\n", 370 __func__, ptr[off])); 371 m_freem(m); 372 return EINVAL; 373 } 374 375 /* Zeroize all other options. */ 376 count = ptr[off + 1]; 377 bcopy(ipseczeroes, ptr, count); 378 off += count; 379 break; 380 } 381 382 /* Sanity check. */ 383 if (off > skip) { 384 DPRINTF(("%s: malformed IPv4 options header\n", 385 __func__)); 386 387 m_freem(m); 388 return EINVAL; 389 } 390 } 391 392 break; 393 #endif /* INET */ 394 395 #ifdef INET6 396 case AF_INET6: /* Ugly... */ 397 /* Copy and "cook" the IPv6 header. */ 398 m_copydata(m, 0, sizeof(ip6), (caddr_t) &ip6); 399 400 /* We don't do IPv6 Jumbograms. */ 401 if (ip6.ip6_plen == 0) { 402 DPRINTF(("%s: unsupported IPv6 jumbogram\n", __func__)); 403 m_freem(m); 404 return EMSGSIZE; 405 } 406 407 ip6.ip6_flow = 0; 408 ip6.ip6_hlim = 0; 409 ip6.ip6_vfc &= ~IPV6_VERSION_MASK; 410 ip6.ip6_vfc |= IPV6_VERSION; 411 412 /* Scoped address handling. */ 413 if (IN6_IS_SCOPE_LINKLOCAL(&ip6.ip6_src)) 414 ip6.ip6_src.s6_addr16[1] = 0; 415 if (IN6_IS_SCOPE_LINKLOCAL(&ip6.ip6_dst)) 416 ip6.ip6_dst.s6_addr16[1] = 0; 417 418 /* Done with IPv6 header. */ 419 m_copyback(m, 0, sizeof(struct ip6_hdr), (caddr_t) &ip6); 420 421 /* Let's deal with the remaining headers (if any). */ 422 if (skip - sizeof(struct ip6_hdr) > 0) { 423 if (m->m_len <= skip) { 424 ptr = (unsigned char *) malloc( 425 skip - sizeof(struct ip6_hdr), 426 M_XDATA, M_NOWAIT); 427 if (ptr == NULL) { 428 DPRINTF(("%s: failed to allocate memory" 429 "for IPv6 headers\n",__func__)); 430 m_freem(m); 431 return ENOBUFS; 432 } 433 434 /* 435 * Copy all the protocol headers after 436 * the IPv6 header. 437 */ 438 m_copydata(m, sizeof(struct ip6_hdr), 439 skip - sizeof(struct ip6_hdr), ptr); 440 alloc = 1; 441 } else { 442 /* No need to allocate memory. */ 443 ptr = mtod(m, unsigned char *) + 444 sizeof(struct ip6_hdr); 445 alloc = 0; 446 } 447 } else 448 break; 449 450 off = ip6.ip6_nxt & 0xff; /* Next header type. */ 451 452 for (len = 0; len < skip - sizeof(struct ip6_hdr);) 453 switch (off) { 454 case IPPROTO_HOPOPTS: 455 case IPPROTO_DSTOPTS: 456 ip6e = (struct ip6_ext *) (ptr + len); 457 458 /* 459 * Process the mutable/immutable 460 * options -- borrows heavily from the 461 * KAME code. 462 */ 463 for (count = len + sizeof(struct ip6_ext); 464 count < len + ((ip6e->ip6e_len + 1) << 3);) { 465 if (ptr[count] == IP6OPT_PAD1) { 466 count++; 467 continue; /* Skip padding. */ 468 } 469 470 /* Sanity check. */ 471 if (count > len + 472 ((ip6e->ip6e_len + 1) << 3)) { 473 m_freem(m); 474 475 /* Free, if we allocated. */ 476 if (alloc) 477 free(ptr, M_XDATA); 478 return EINVAL; 479 } 480 481 ad = ptr[count + 1]; 482 483 /* If mutable option, zeroize. */ 484 if (ptr[count] & IP6OPT_MUTABLE) 485 bcopy(ipseczeroes, ptr + count, 486 ptr[count + 1]); 487 488 count += ad; 489 490 /* Sanity check. */ 491 if (count > 492 skip - sizeof(struct ip6_hdr)) { 493 m_freem(m); 494 495 /* Free, if we allocated. */ 496 if (alloc) 497 free(ptr, M_XDATA); 498 return EINVAL; 499 } 500 } 501 502 /* Advance. */ 503 len += ((ip6e->ip6e_len + 1) << 3); 504 off = ip6e->ip6e_nxt; 505 break; 506 507 case IPPROTO_ROUTING: 508 /* 509 * Always include routing headers in 510 * computation. 511 */ 512 ip6e = (struct ip6_ext *) (ptr + len); 513 len += ((ip6e->ip6e_len + 1) << 3); 514 off = ip6e->ip6e_nxt; 515 break; 516 517 default: 518 DPRINTF(("%s: unexpected IPv6 header type %d", 519 __func__, off)); 520 if (alloc) 521 free(ptr, M_XDATA); 522 m_freem(m); 523 return EINVAL; 524 } 525 526 /* Copyback and free, if we allocated. */ 527 if (alloc) { 528 m_copyback(m, sizeof(struct ip6_hdr), 529 skip - sizeof(struct ip6_hdr), ptr); 530 free(ptr, M_XDATA); 531 } 532 533 break; 534 #endif /* INET6 */ 535 } 536 537 return 0; 538 } 539 540 /* 541 * ah_input() gets called to verify that an input packet 542 * passes authentication. 543 */ 544 static int 545 ah_input(struct mbuf *m, struct secasvar *sav, int skip, int protoff) 546 { 547 IPSEC_DEBUG_DECLARE(char buf[128]); 548 const struct auth_hash *ahx; 549 struct cryptodesc *crda; 550 struct cryptop *crp; 551 struct xform_data *xd; 552 struct newah *ah; 553 uint64_t cryptoid; 554 int hl, rplen, authsize, error; 555 556 IPSEC_ASSERT(sav != NULL, ("null SA")); 557 IPSEC_ASSERT(sav->key_auth != NULL, ("null authentication key")); 558 IPSEC_ASSERT(sav->tdb_authalgxform != NULL, 559 ("null authentication xform")); 560 561 /* Figure out header size. */ 562 rplen = HDRSIZE(sav); 563 564 /* XXX don't pullup, just copy header */ 565 IP6_EXTHDR_GET(ah, struct newah *, m, skip, rplen); 566 if (ah == NULL) { 567 DPRINTF(("ah_input: cannot pullup header\n")); 568 AHSTAT_INC(ahs_hdrops); /*XXX*/ 569 error = ENOBUFS; 570 goto bad; 571 } 572 573 /* Check replay window, if applicable. */ 574 SECASVAR_LOCK(sav); 575 if (sav->replay != NULL && sav->replay->wsize != 0 && 576 ipsec_chkreplay(ntohl(ah->ah_seq), sav) == 0) { 577 SECASVAR_UNLOCK(sav); 578 AHSTAT_INC(ahs_replay); 579 DPRINTF(("%s: packet replay failure: %s\n", __func__, 580 ipsec_sa2str(sav, buf, sizeof(buf)))); 581 error = EACCES; 582 goto bad; 583 } 584 cryptoid = sav->tdb_cryptoid; 585 SECASVAR_UNLOCK(sav); 586 587 /* Verify AH header length. */ 588 hl = ah->ah_len * sizeof (u_int32_t); 589 ahx = sav->tdb_authalgxform; 590 authsize = AUTHSIZE(sav); 591 if (hl != authsize + rplen - sizeof (struct ah)) { 592 DPRINTF(("%s: bad authenticator length %u (expecting %lu)" 593 " for packet in SA %s/%08lx\n", __func__, hl, 594 (u_long) (authsize + rplen - sizeof (struct ah)), 595 ipsec_address(&sav->sah->saidx.dst, buf, sizeof(buf)), 596 (u_long) ntohl(sav->spi))); 597 AHSTAT_INC(ahs_badauthl); 598 error = EACCES; 599 goto bad; 600 } 601 AHSTAT_ADD(ahs_ibytes, m->m_pkthdr.len - skip - hl); 602 603 /* Get crypto descriptors. */ 604 crp = crypto_getreq(1); 605 if (crp == NULL) { 606 DPRINTF(("%s: failed to acquire crypto descriptor\n", 607 __func__)); 608 AHSTAT_INC(ahs_crypto); 609 error = ENOBUFS; 610 goto bad; 611 } 612 613 crda = crp->crp_desc; 614 IPSEC_ASSERT(crda != NULL, ("null crypto descriptor")); 615 616 crda->crd_skip = 0; 617 crda->crd_len = m->m_pkthdr.len; 618 crda->crd_inject = skip + rplen; 619 620 /* Authentication operation. */ 621 crda->crd_alg = ahx->type; 622 crda->crd_klen = _KEYBITS(sav->key_auth); 623 crda->crd_key = sav->key_auth->key_data; 624 625 /* Allocate IPsec-specific opaque crypto info. */ 626 xd = malloc(sizeof(*xd) + skip + rplen + authsize, M_XDATA, 627 M_NOWAIT | M_ZERO); 628 if (xd == NULL) { 629 DPRINTF(("%s: failed to allocate xform_data\n", __func__)); 630 AHSTAT_INC(ahs_crypto); 631 crypto_freereq(crp); 632 error = ENOBUFS; 633 goto bad; 634 } 635 636 /* 637 * Save the authenticator, the skipped portion of the packet, 638 * and the AH header. 639 */ 640 m_copydata(m, 0, skip + rplen + authsize, (caddr_t)(xd + 1)); 641 642 /* Zeroize the authenticator on the packet. */ 643 m_copyback(m, skip + rplen, authsize, ipseczeroes); 644 645 /* "Massage" the packet headers for crypto processing. */ 646 error = ah_massage_headers(&m, sav->sah->saidx.dst.sa.sa_family, 647 skip, ahx->type, 0); 648 if (error != 0) { 649 /* NB: mbuf is free'd by ah_massage_headers */ 650 AHSTAT_INC(ahs_hdrops); 651 free(xd, M_XDATA); 652 crypto_freereq(crp); 653 key_freesav(&sav); 654 return (error); 655 } 656 657 /* Crypto operation descriptor. */ 658 crp->crp_ilen = m->m_pkthdr.len; /* Total input length. */ 659 crp->crp_flags = CRYPTO_F_IMBUF | CRYPTO_F_CBIFSYNC; 660 if (V_async_crypto) 661 crp->crp_flags |= CRYPTO_F_ASYNC | CRYPTO_F_ASYNC_KEEPORDER; 662 crp->crp_buf = (caddr_t) m; 663 crp->crp_callback = ah_input_cb; 664 crp->crp_sid = cryptoid; 665 crp->crp_opaque = (caddr_t) xd; 666 667 /* These are passed as-is to the callback. */ 668 xd->sav = sav; 669 xd->nxt = ah->ah_nxt; 670 xd->protoff = protoff; 671 xd->skip = skip; 672 xd->cryptoid = cryptoid; 673 return (crypto_dispatch(crp)); 674 bad: 675 m_freem(m); 676 key_freesav(&sav); 677 return (error); 678 } 679 680 /* 681 * AH input callback from the crypto driver. 682 */ 683 static int 684 ah_input_cb(struct cryptop *crp) 685 { 686 IPSEC_DEBUG_DECLARE(char buf[IPSEC_ADDRSTRLEN]); 687 unsigned char calc[AH_ALEN_MAX]; 688 const struct auth_hash *ahx; 689 struct mbuf *m; 690 struct cryptodesc *crd; 691 struct xform_data *xd; 692 struct secasvar *sav; 693 struct secasindex *saidx; 694 caddr_t ptr; 695 uint64_t cryptoid; 696 int authsize, rplen, error, skip, protoff; 697 uint8_t nxt; 698 699 crd = crp->crp_desc; 700 m = (struct mbuf *) crp->crp_buf; 701 xd = (struct xform_data *) crp->crp_opaque; 702 sav = xd->sav; 703 skip = xd->skip; 704 nxt = xd->nxt; 705 protoff = xd->protoff; 706 cryptoid = xd->cryptoid; 707 saidx = &sav->sah->saidx; 708 IPSEC_ASSERT(saidx->dst.sa.sa_family == AF_INET || 709 saidx->dst.sa.sa_family == AF_INET6, 710 ("unexpected protocol family %u", saidx->dst.sa.sa_family)); 711 712 ahx = sav->tdb_authalgxform; 713 714 /* Check for crypto errors. */ 715 if (crp->crp_etype) { 716 if (crp->crp_etype == EAGAIN) { 717 /* Reset the session ID */ 718 if (ipsec_updateid(sav, &crp->crp_sid, &cryptoid) != 0) 719 crypto_freesession(cryptoid); 720 xd->cryptoid = crp->crp_sid; 721 return (crypto_dispatch(crp)); 722 } 723 AHSTAT_INC(ahs_noxform); 724 DPRINTF(("%s: crypto error %d\n", __func__, crp->crp_etype)); 725 error = crp->crp_etype; 726 goto bad; 727 } else { 728 AHSTAT_INC(ahs_hist[sav->alg_auth]); 729 crypto_freereq(crp); /* No longer needed. */ 730 crp = NULL; 731 } 732 733 /* Shouldn't happen... */ 734 if (m == NULL) { 735 AHSTAT_INC(ahs_crypto); 736 DPRINTF(("%s: bogus returned buffer from crypto\n", __func__)); 737 error = EINVAL; 738 goto bad; 739 } 740 741 /* Figure out header size. */ 742 rplen = HDRSIZE(sav); 743 authsize = AUTHSIZE(sav); 744 745 /* Copy authenticator off the packet. */ 746 m_copydata(m, skip + rplen, authsize, calc); 747 748 /* Verify authenticator. */ 749 ptr = (caddr_t) (xd + 1); 750 if (timingsafe_bcmp(ptr + skip + rplen, calc, authsize)) { 751 DPRINTF(("%s: authentication hash mismatch for packet " 752 "in SA %s/%08lx\n", __func__, 753 ipsec_address(&saidx->dst, buf, sizeof(buf)), 754 (u_long) ntohl(sav->spi))); 755 AHSTAT_INC(ahs_badauth); 756 error = EACCES; 757 goto bad; 758 } 759 /* Fix the Next Protocol field. */ 760 ((uint8_t *) ptr)[protoff] = nxt; 761 762 /* Copyback the saved (uncooked) network headers. */ 763 m_copyback(m, 0, skip, ptr); 764 free(xd, M_XDATA), xd = NULL; /* No longer needed */ 765 766 /* 767 * Header is now authenticated. 768 */ 769 m->m_flags |= M_AUTHIPHDR|M_AUTHIPDGM; 770 771 /* 772 * Update replay sequence number, if appropriate. 773 */ 774 if (sav->replay) { 775 u_int32_t seq; 776 777 m_copydata(m, skip + offsetof(struct newah, ah_seq), 778 sizeof (seq), (caddr_t) &seq); 779 SECASVAR_LOCK(sav); 780 if (ipsec_updatereplay(ntohl(seq), sav)) { 781 SECASVAR_UNLOCK(sav); 782 AHSTAT_INC(ahs_replay); 783 error = EACCES; 784 goto bad; 785 } 786 SECASVAR_UNLOCK(sav); 787 } 788 789 /* 790 * Remove the AH header and authenticator from the mbuf. 791 */ 792 error = m_striphdr(m, skip, rplen + authsize); 793 if (error) { 794 DPRINTF(("%s: mangled mbuf chain for SA %s/%08lx\n", __func__, 795 ipsec_address(&saidx->dst, buf, sizeof(buf)), 796 (u_long) ntohl(sav->spi))); 797 AHSTAT_INC(ahs_hdrops); 798 goto bad; 799 } 800 801 switch (saidx->dst.sa.sa_family) { 802 #ifdef INET6 803 case AF_INET6: 804 error = ipsec6_common_input_cb(m, sav, skip, protoff); 805 break; 806 #endif 807 #ifdef INET 808 case AF_INET: 809 error = ipsec4_common_input_cb(m, sav, skip, protoff); 810 break; 811 #endif 812 default: 813 panic("%s: Unexpected address family: %d saidx=%p", __func__, 814 saidx->dst.sa.sa_family, saidx); 815 } 816 return error; 817 bad: 818 if (sav) 819 key_freesav(&sav); 820 if (m != NULL) 821 m_freem(m); 822 if (xd != NULL) 823 free(xd, M_XDATA); 824 if (crp != NULL) 825 crypto_freereq(crp); 826 return error; 827 } 828 829 /* 830 * AH output routine, called by ipsec[46]_perform_request(). 831 */ 832 static int 833 ah_output(struct mbuf *m, struct secpolicy *sp, struct secasvar *sav, 834 u_int idx, int skip, int protoff) 835 { 836 IPSEC_DEBUG_DECLARE(char buf[IPSEC_ADDRSTRLEN]); 837 const struct auth_hash *ahx; 838 struct cryptodesc *crda; 839 struct xform_data *xd; 840 struct mbuf *mi; 841 struct cryptop *crp; 842 struct newah *ah; 843 uint64_t cryptoid; 844 uint16_t iplen; 845 int error, rplen, authsize, maxpacketsize, roff; 846 uint8_t prot; 847 848 IPSEC_ASSERT(sav != NULL, ("null SA")); 849 ahx = sav->tdb_authalgxform; 850 IPSEC_ASSERT(ahx != NULL, ("null authentication xform")); 851 852 AHSTAT_INC(ahs_output); 853 854 /* Figure out header size. */ 855 rplen = HDRSIZE(sav); 856 857 /* Check for maximum packet size violations. */ 858 switch (sav->sah->saidx.dst.sa.sa_family) { 859 #ifdef INET 860 case AF_INET: 861 maxpacketsize = IP_MAXPACKET; 862 break; 863 #endif /* INET */ 864 #ifdef INET6 865 case AF_INET6: 866 maxpacketsize = IPV6_MAXPACKET; 867 break; 868 #endif /* INET6 */ 869 default: 870 DPRINTF(("%s: unknown/unsupported protocol family %u, " 871 "SA %s/%08lx\n", __func__, 872 sav->sah->saidx.dst.sa.sa_family, 873 ipsec_address(&sav->sah->saidx.dst, buf, sizeof(buf)), 874 (u_long) ntohl(sav->spi))); 875 AHSTAT_INC(ahs_nopf); 876 error = EPFNOSUPPORT; 877 goto bad; 878 } 879 authsize = AUTHSIZE(sav); 880 if (rplen + authsize + m->m_pkthdr.len > maxpacketsize) { 881 DPRINTF(("%s: packet in SA %s/%08lx got too big " 882 "(len %u, max len %u)\n", __func__, 883 ipsec_address(&sav->sah->saidx.dst, buf, sizeof(buf)), 884 (u_long) ntohl(sav->spi), 885 rplen + authsize + m->m_pkthdr.len, maxpacketsize)); 886 AHSTAT_INC(ahs_toobig); 887 error = EMSGSIZE; 888 goto bad; 889 } 890 891 /* Update the counters. */ 892 AHSTAT_ADD(ahs_obytes, m->m_pkthdr.len - skip); 893 894 m = m_unshare(m, M_NOWAIT); 895 if (m == NULL) { 896 DPRINTF(("%s: cannot clone mbuf chain, SA %s/%08lx\n", __func__, 897 ipsec_address(&sav->sah->saidx.dst, buf, sizeof(buf)), 898 (u_long) ntohl(sav->spi))); 899 AHSTAT_INC(ahs_hdrops); 900 error = ENOBUFS; 901 goto bad; 902 } 903 904 /* Inject AH header. */ 905 mi = m_makespace(m, skip, rplen + authsize, &roff); 906 if (mi == NULL) { 907 DPRINTF(("%s: failed to inject %u byte AH header for SA " 908 "%s/%08lx\n", __func__, 909 rplen + authsize, 910 ipsec_address(&sav->sah->saidx.dst, buf, sizeof(buf)), 911 (u_long) ntohl(sav->spi))); 912 AHSTAT_INC(ahs_hdrops); /*XXX differs from openbsd */ 913 error = ENOBUFS; 914 goto bad; 915 } 916 917 /* 918 * The AH header is guaranteed by m_makespace() to be in 919 * contiguous memory, at roff bytes offset into the returned mbuf. 920 */ 921 ah = (struct newah *)(mtod(mi, caddr_t) + roff); 922 923 /* Initialize the AH header. */ 924 m_copydata(m, protoff, sizeof(u_int8_t), (caddr_t) &ah->ah_nxt); 925 ah->ah_len = (rplen + authsize - sizeof(struct ah)) / sizeof(u_int32_t); 926 ah->ah_reserve = 0; 927 ah->ah_spi = sav->spi; 928 929 /* Zeroize authenticator. */ 930 m_copyback(m, skip + rplen, authsize, ipseczeroes); 931 932 /* Insert packet replay counter, as requested. */ 933 SECASVAR_LOCK(sav); 934 if (sav->replay) { 935 if (sav->replay->count == ~0 && 936 (sav->flags & SADB_X_EXT_CYCSEQ) == 0) { 937 SECASVAR_UNLOCK(sav); 938 DPRINTF(("%s: replay counter wrapped for SA %s/%08lx\n", 939 __func__, ipsec_address(&sav->sah->saidx.dst, buf, 940 sizeof(buf)), (u_long) ntohl(sav->spi))); 941 AHSTAT_INC(ahs_wrap); 942 error = EACCES; 943 goto bad; 944 } 945 #ifdef REGRESSION 946 /* Emulate replay attack when ipsec_replay is TRUE. */ 947 if (!V_ipsec_replay) 948 #endif 949 sav->replay->count++; 950 ah->ah_seq = htonl(sav->replay->count); 951 } 952 cryptoid = sav->tdb_cryptoid; 953 SECASVAR_UNLOCK(sav); 954 955 /* Get crypto descriptors. */ 956 crp = crypto_getreq(1); 957 if (crp == NULL) { 958 DPRINTF(("%s: failed to acquire crypto descriptors\n", 959 __func__)); 960 AHSTAT_INC(ahs_crypto); 961 error = ENOBUFS; 962 goto bad; 963 } 964 965 crda = crp->crp_desc; 966 crda->crd_skip = 0; 967 crda->crd_inject = skip + rplen; 968 crda->crd_len = m->m_pkthdr.len; 969 970 /* Authentication operation. */ 971 crda->crd_alg = ahx->type; 972 crda->crd_key = sav->key_auth->key_data; 973 crda->crd_klen = _KEYBITS(sav->key_auth); 974 975 /* Allocate IPsec-specific opaque crypto info. */ 976 xd = malloc(sizeof(struct xform_data) + skip, M_XDATA, 977 M_NOWAIT | M_ZERO); 978 if (xd == NULL) { 979 crypto_freereq(crp); 980 DPRINTF(("%s: failed to allocate xform_data\n", __func__)); 981 AHSTAT_INC(ahs_crypto); 982 error = ENOBUFS; 983 goto bad; 984 } 985 986 /* Save the skipped portion of the packet. */ 987 m_copydata(m, 0, skip, (caddr_t) (xd + 1)); 988 989 /* 990 * Fix IP header length on the header used for 991 * authentication. We don't need to fix the original 992 * header length as it will be fixed by our caller. 993 */ 994 switch (sav->sah->saidx.dst.sa.sa_family) { 995 #ifdef INET 996 case AF_INET: 997 bcopy(((caddr_t)(xd + 1)) + 998 offsetof(struct ip, ip_len), 999 (caddr_t) &iplen, sizeof(u_int16_t)); 1000 iplen = htons(ntohs(iplen) + rplen + authsize); 1001 m_copyback(m, offsetof(struct ip, ip_len), 1002 sizeof(u_int16_t), (caddr_t) &iplen); 1003 break; 1004 #endif /* INET */ 1005 1006 #ifdef INET6 1007 case AF_INET6: 1008 bcopy(((caddr_t)(xd + 1)) + 1009 offsetof(struct ip6_hdr, ip6_plen), 1010 (caddr_t) &iplen, sizeof(uint16_t)); 1011 iplen = htons(ntohs(iplen) + rplen + authsize); 1012 m_copyback(m, offsetof(struct ip6_hdr, ip6_plen), 1013 sizeof(uint16_t), (caddr_t) &iplen); 1014 break; 1015 #endif /* INET6 */ 1016 } 1017 1018 /* Fix the Next Header field in saved header. */ 1019 ((uint8_t *) (xd + 1))[protoff] = IPPROTO_AH; 1020 1021 /* Update the Next Protocol field in the IP header. */ 1022 prot = IPPROTO_AH; 1023 m_copyback(m, protoff, sizeof(uint8_t), (caddr_t) &prot); 1024 1025 /* "Massage" the packet headers for crypto processing. */ 1026 error = ah_massage_headers(&m, sav->sah->saidx.dst.sa.sa_family, 1027 skip, ahx->type, 1); 1028 if (error != 0) { 1029 m = NULL; /* mbuf was free'd by ah_massage_headers. */ 1030 free(xd, M_XDATA); 1031 crypto_freereq(crp); 1032 goto bad; 1033 } 1034 1035 /* Crypto operation descriptor. */ 1036 crp->crp_ilen = m->m_pkthdr.len; /* Total input length. */ 1037 crp->crp_flags = CRYPTO_F_IMBUF | CRYPTO_F_CBIFSYNC; 1038 if (V_async_crypto) 1039 crp->crp_flags |= CRYPTO_F_ASYNC | CRYPTO_F_ASYNC_KEEPORDER; 1040 crp->crp_buf = (caddr_t) m; 1041 crp->crp_callback = ah_output_cb; 1042 crp->crp_sid = cryptoid; 1043 crp->crp_opaque = (caddr_t) xd; 1044 1045 /* These are passed as-is to the callback. */ 1046 xd->sp = sp; 1047 xd->sav = sav; 1048 xd->skip = skip; 1049 xd->idx = idx; 1050 xd->cryptoid = cryptoid; 1051 1052 return crypto_dispatch(crp); 1053 bad: 1054 if (m) 1055 m_freem(m); 1056 key_freesav(&sav); 1057 key_freesp(&sp); 1058 return (error); 1059 } 1060 1061 /* 1062 * AH output callback from the crypto driver. 1063 */ 1064 static int 1065 ah_output_cb(struct cryptop *crp) 1066 { 1067 struct xform_data *xd; 1068 struct secpolicy *sp; 1069 struct secasvar *sav; 1070 struct mbuf *m; 1071 uint64_t cryptoid; 1072 caddr_t ptr; 1073 u_int idx; 1074 int skip, error; 1075 1076 m = (struct mbuf *) crp->crp_buf; 1077 xd = (struct xform_data *) crp->crp_opaque; 1078 sp = xd->sp; 1079 sav = xd->sav; 1080 skip = xd->skip; 1081 idx = xd->idx; 1082 cryptoid = xd->cryptoid; 1083 ptr = (caddr_t) (xd + 1); 1084 1085 /* Check for crypto errors. */ 1086 if (crp->crp_etype) { 1087 if (crp->crp_etype == EAGAIN) { 1088 /* Reset the session ID */ 1089 if (ipsec_updateid(sav, &crp->crp_sid, &cryptoid) != 0) 1090 crypto_freesession(cryptoid); 1091 xd->cryptoid = crp->crp_sid; 1092 return (crypto_dispatch(crp)); 1093 } 1094 AHSTAT_INC(ahs_noxform); 1095 DPRINTF(("%s: crypto error %d\n", __func__, crp->crp_etype)); 1096 error = crp->crp_etype; 1097 m_freem(m); 1098 goto bad; 1099 } 1100 1101 /* Shouldn't happen... */ 1102 if (m == NULL) { 1103 AHSTAT_INC(ahs_crypto); 1104 DPRINTF(("%s: bogus returned buffer from crypto\n", __func__)); 1105 error = EINVAL; 1106 goto bad; 1107 } 1108 /* 1109 * Copy original headers (with the new protocol number) back 1110 * in place. 1111 */ 1112 m_copyback(m, 0, skip, ptr); 1113 1114 free(xd, M_XDATA); 1115 crypto_freereq(crp); 1116 AHSTAT_INC(ahs_hist[sav->alg_auth]); 1117 #ifdef REGRESSION 1118 /* Emulate man-in-the-middle attack when ipsec_integrity is TRUE. */ 1119 if (V_ipsec_integrity) { 1120 int alen; 1121 1122 /* 1123 * Corrupt HMAC if we want to test integrity verification of 1124 * the other side. 1125 */ 1126 alen = AUTHSIZE(sav); 1127 m_copyback(m, m->m_pkthdr.len - alen, alen, ipseczeroes); 1128 } 1129 #endif 1130 1131 /* NB: m is reclaimed by ipsec_process_done. */ 1132 error = ipsec_process_done(m, sp, sav, idx); 1133 return (error); 1134 bad: 1135 free(xd, M_XDATA); 1136 crypto_freereq(crp); 1137 key_freesav(&sav); 1138 key_freesp(&sp); 1139 return (error); 1140 } 1141 1142 static struct xformsw ah_xformsw = { 1143 .xf_type = XF_AH, 1144 .xf_name = "IPsec AH", 1145 .xf_init = ah_init, 1146 .xf_zeroize = ah_zeroize, 1147 .xf_input = ah_input, 1148 .xf_output = ah_output, 1149 }; 1150 1151 SYSINIT(ah_xform_init, SI_SUB_PROTO_DOMAIN, SI_ORDER_MIDDLE, 1152 xform_attach, &ah_xformsw); 1153 SYSUNINIT(ah_xform_uninit, SI_SUB_PROTO_DOMAIN, SI_ORDER_MIDDLE, 1154 xform_detach, &ah_xformsw); 1155