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, rplen, align; 151 152 IPSEC_ASSERT(sav->tdb_authalgxform != NULL, ("null xform")); 153 /*XXX not right for null algorithm--does it matter??*/ 154 155 /* RFC4302: use the correct alignment. */ 156 align = sizeof(uint32_t); 157 #ifdef INET6 158 if (sav->sah->saidx.dst.sa.sa_family == AF_INET6) { 159 align = sizeof(uint64_t); 160 } 161 #endif 162 rplen = HDRSIZE(sav); 163 authsize = AUTHSIZE(sav); 164 size = roundup(rplen + authsize, align); 165 } else { 166 /* default guess */ 167 size = sizeof (struct ah) + sizeof (u_int32_t) + 16; 168 } 169 return size; 170 } 171 172 /* 173 * NB: public for use by esp_init. 174 */ 175 int 176 ah_init0(struct secasvar *sav, struct xformsw *xsp, struct cryptoini *cria) 177 { 178 const struct auth_hash *thash; 179 int keylen; 180 181 thash = auth_algorithm_lookup(sav->alg_auth); 182 if (thash == NULL) { 183 DPRINTF(("%s: unsupported authentication algorithm %u\n", 184 __func__, sav->alg_auth)); 185 return EINVAL; 186 } 187 /* 188 * Verify the replay state block allocation is consistent with 189 * the protocol type. We check here so we can make assumptions 190 * later during protocol processing. 191 */ 192 /* NB: replay state is setup elsewhere (sigh) */ 193 if (((sav->flags&SADB_X_EXT_OLD) == 0) ^ (sav->replay != NULL)) { 194 DPRINTF(("%s: replay state block inconsistency, " 195 "%s algorithm %s replay state\n", __func__, 196 (sav->flags & SADB_X_EXT_OLD) ? "old" : "new", 197 sav->replay == NULL ? "without" : "with")); 198 return EINVAL; 199 } 200 if (sav->key_auth == NULL) { 201 DPRINTF(("%s: no authentication key for %s algorithm\n", 202 __func__, thash->name)); 203 return EINVAL; 204 } 205 keylen = _KEYLEN(sav->key_auth); 206 if (keylen > thash->keysize && thash->keysize != 0) { 207 DPRINTF(("%s: invalid keylength %d, algorithm %s requires " 208 "keysize less than %d\n", __func__, 209 keylen, thash->name, thash->keysize)); 210 return EINVAL; 211 } 212 213 sav->tdb_xform = xsp; 214 sav->tdb_authalgxform = thash; 215 216 /* Initialize crypto session. */ 217 bzero(cria, sizeof (*cria)); 218 cria->cri_alg = sav->tdb_authalgxform->type; 219 cria->cri_klen = _KEYBITS(sav->key_auth); 220 cria->cri_key = sav->key_auth->key_data; 221 cria->cri_mlen = AUTHSIZE(sav); 222 223 return 0; 224 } 225 226 /* 227 * ah_init() is called when an SPI is being set up. 228 */ 229 static int 230 ah_init(struct secasvar *sav, struct xformsw *xsp) 231 { 232 struct cryptoini cria; 233 int error; 234 235 error = ah_init0(sav, xsp, &cria); 236 return error ? error : 237 crypto_newsession(&sav->tdb_cryptoid, &cria, V_crypto_support); 238 } 239 240 /* 241 * Paranoia. 242 * 243 * NB: public for use by esp_zeroize (XXX). 244 */ 245 int 246 ah_zeroize(struct secasvar *sav) 247 { 248 249 if (sav->key_auth) 250 bzero(sav->key_auth->key_data, _KEYLEN(sav->key_auth)); 251 252 crypto_freesession(sav->tdb_cryptoid); 253 sav->tdb_cryptoid = NULL; 254 sav->tdb_authalgxform = NULL; 255 sav->tdb_xform = NULL; 256 return 0; 257 } 258 259 /* 260 * Massage IPv4/IPv6 headers for AH processing. 261 */ 262 static int 263 ah_massage_headers(struct mbuf **m0, int proto, int skip, int alg, int out) 264 { 265 struct mbuf *m = *m0; 266 unsigned char *ptr; 267 int off, count; 268 269 #ifdef INET 270 struct ip *ip; 271 #endif /* INET */ 272 273 #ifdef INET6 274 struct ip6_ext *ip6e; 275 struct ip6_hdr ip6; 276 int ad, alloc, nxt, noff; 277 #endif /* INET6 */ 278 279 switch (proto) { 280 #ifdef INET 281 case AF_INET: 282 /* 283 * This is the least painful way of dealing with IPv4 header 284 * and option processing -- just make sure they're in 285 * contiguous memory. 286 */ 287 *m0 = m = m_pullup(m, skip); 288 if (m == NULL) { 289 DPRINTF(("%s: m_pullup failed\n", __func__)); 290 return ENOBUFS; 291 } 292 293 /* Fix the IP header */ 294 ip = mtod(m, struct ip *); 295 if (V_ah_cleartos) 296 ip->ip_tos = 0; 297 ip->ip_ttl = 0; 298 ip->ip_sum = 0; 299 300 if (alg == CRYPTO_MD5_KPDK || alg == CRYPTO_SHA1_KPDK) 301 ip->ip_off &= htons(IP_DF); 302 else 303 ip->ip_off = htons(0); 304 305 ptr = mtod(m, unsigned char *); 306 307 /* IPv4 option processing */ 308 for (off = sizeof(struct ip); off < skip;) { 309 if (ptr[off] == IPOPT_EOL || ptr[off] == IPOPT_NOP || 310 off + 1 < skip) 311 ; 312 else { 313 DPRINTF(("%s: illegal IPv4 option length for " 314 "option %d\n", __func__, ptr[off])); 315 316 m_freem(m); 317 return EINVAL; 318 } 319 320 switch (ptr[off]) { 321 case IPOPT_EOL: 322 off = skip; /* End the loop. */ 323 break; 324 325 case IPOPT_NOP: 326 off++; 327 break; 328 329 case IPOPT_SECURITY: /* 0x82 */ 330 case 0x85: /* Extended security. */ 331 case 0x86: /* Commercial security. */ 332 case 0x94: /* Router alert */ 333 case 0x95: /* RFC1770 */ 334 /* Sanity check for option length. */ 335 if (ptr[off + 1] < 2) { 336 DPRINTF(("%s: illegal IPv4 option " 337 "length for option %d\n", 338 __func__, ptr[off])); 339 340 m_freem(m); 341 return EINVAL; 342 } 343 344 off += ptr[off + 1]; 345 break; 346 347 case IPOPT_LSRR: 348 case IPOPT_SSRR: 349 /* Sanity check for option length. */ 350 if (ptr[off + 1] < 2) { 351 DPRINTF(("%s: illegal IPv4 option " 352 "length for option %d\n", 353 __func__, ptr[off])); 354 355 m_freem(m); 356 return EINVAL; 357 } 358 359 /* 360 * On output, if we have either of the 361 * source routing options, we should 362 * swap the destination address of the 363 * IP header with the last address 364 * specified in the option, as that is 365 * what the destination's IP header 366 * will look like. 367 */ 368 if (out) 369 bcopy(ptr + off + ptr[off + 1] - 370 sizeof(struct in_addr), 371 &(ip->ip_dst), sizeof(struct in_addr)); 372 373 /* Fall through */ 374 default: 375 /* Sanity check for option length. */ 376 if (ptr[off + 1] < 2) { 377 DPRINTF(("%s: illegal IPv4 option " 378 "length for option %d\n", 379 __func__, ptr[off])); 380 m_freem(m); 381 return EINVAL; 382 } 383 384 /* Zeroize all other options. */ 385 count = ptr[off + 1]; 386 bcopy(ipseczeroes, ptr + off, count); 387 off += count; 388 break; 389 } 390 391 /* Sanity check. */ 392 if (off > skip) { 393 DPRINTF(("%s: malformed IPv4 options header\n", 394 __func__)); 395 396 m_freem(m); 397 return EINVAL; 398 } 399 } 400 401 break; 402 #endif /* INET */ 403 404 #ifdef INET6 405 case AF_INET6: /* Ugly... */ 406 /* Copy and "cook" the IPv6 header. */ 407 m_copydata(m, 0, sizeof(ip6), (caddr_t) &ip6); 408 409 /* We don't do IPv6 Jumbograms. */ 410 if (ip6.ip6_plen == 0) { 411 DPRINTF(("%s: unsupported IPv6 jumbogram\n", __func__)); 412 m_freem(m); 413 return EMSGSIZE; 414 } 415 416 ip6.ip6_flow = 0; 417 ip6.ip6_hlim = 0; 418 ip6.ip6_vfc &= ~IPV6_VERSION_MASK; 419 ip6.ip6_vfc |= IPV6_VERSION; 420 421 /* Scoped address handling. */ 422 if (IN6_IS_SCOPE_LINKLOCAL(&ip6.ip6_src)) 423 ip6.ip6_src.s6_addr16[1] = 0; 424 if (IN6_IS_SCOPE_LINKLOCAL(&ip6.ip6_dst)) 425 ip6.ip6_dst.s6_addr16[1] = 0; 426 427 /* Done with IPv6 header. */ 428 m_copyback(m, 0, sizeof(struct ip6_hdr), (caddr_t) &ip6); 429 430 /* Let's deal with the remaining headers (if any). */ 431 if (skip - sizeof(struct ip6_hdr) > 0) { 432 if (m->m_len <= skip) { 433 ptr = (unsigned char *) malloc( 434 skip - sizeof(struct ip6_hdr), 435 M_XDATA, M_NOWAIT); 436 if (ptr == NULL) { 437 DPRINTF(("%s: failed to allocate memory" 438 "for IPv6 headers\n",__func__)); 439 m_freem(m); 440 return ENOBUFS; 441 } 442 443 /* 444 * Copy all the protocol headers after 445 * the IPv6 header. 446 */ 447 m_copydata(m, sizeof(struct ip6_hdr), 448 skip - sizeof(struct ip6_hdr), ptr); 449 alloc = 1; 450 } else { 451 /* No need to allocate memory. */ 452 ptr = mtod(m, unsigned char *) + 453 sizeof(struct ip6_hdr); 454 alloc = 0; 455 } 456 } else 457 break; 458 459 nxt = ip6.ip6_nxt & 0xff; /* Next header type. */ 460 461 for (off = 0; off < skip - sizeof(struct ip6_hdr);) 462 switch (nxt) { 463 case IPPROTO_HOPOPTS: 464 case IPPROTO_DSTOPTS: 465 ip6e = (struct ip6_ext *)(ptr + off); 466 noff = off + ((ip6e->ip6e_len + 1) << 3); 467 468 /* Sanity check. */ 469 if (noff > skip - sizeof(struct ip6_hdr)) 470 goto error6; 471 472 /* 473 * Zero out mutable options. 474 */ 475 for (count = off + sizeof(struct ip6_ext); 476 count < noff;) { 477 if (ptr[count] == IP6OPT_PAD1) { 478 count++; 479 continue; /* Skip padding. */ 480 } 481 482 ad = ptr[count + 1] + 2; 483 if (count + ad > noff) 484 goto error6; 485 486 if (ptr[count] & IP6OPT_MUTABLE) 487 memset(ptr + count, 0, ad); 488 count += ad; 489 } 490 491 if (count != noff) 492 goto error6; 493 494 /* Advance. */ 495 off += ((ip6e->ip6e_len + 1) << 3); 496 nxt = ip6e->ip6e_nxt; 497 break; 498 499 case IPPROTO_ROUTING: 500 /* 501 * Always include routing headers in 502 * computation. 503 */ 504 ip6e = (struct ip6_ext *) (ptr + off); 505 off += ((ip6e->ip6e_len + 1) << 3); 506 nxt = ip6e->ip6e_nxt; 507 break; 508 509 default: 510 DPRINTF(("%s: unexpected IPv6 header type %d", 511 __func__, off)); 512 error6: 513 if (alloc) 514 free(ptr, M_XDATA); 515 m_freem(m); 516 return EINVAL; 517 } 518 519 /* Copyback and free, if we allocated. */ 520 if (alloc) { 521 m_copyback(m, sizeof(struct ip6_hdr), 522 skip - sizeof(struct ip6_hdr), ptr); 523 free(ptr, M_XDATA); 524 } 525 526 break; 527 #endif /* INET6 */ 528 } 529 530 return 0; 531 } 532 533 /* 534 * ah_input() gets called to verify that an input packet 535 * passes authentication. 536 */ 537 static int 538 ah_input(struct mbuf *m, struct secasvar *sav, int skip, int protoff) 539 { 540 IPSEC_DEBUG_DECLARE(char buf[128]); 541 const struct auth_hash *ahx; 542 struct cryptodesc *crda; 543 struct cryptop *crp; 544 struct xform_data *xd; 545 struct newah *ah; 546 crypto_session_t cryptoid; 547 int hl, rplen, authsize, ahsize, error; 548 549 IPSEC_ASSERT(sav != NULL, ("null SA")); 550 IPSEC_ASSERT(sav->key_auth != NULL, ("null authentication key")); 551 IPSEC_ASSERT(sav->tdb_authalgxform != NULL, 552 ("null authentication xform")); 553 554 /* Figure out header size. */ 555 rplen = HDRSIZE(sav); 556 557 /* XXX don't pullup, just copy header */ 558 IP6_EXTHDR_GET(ah, struct newah *, m, skip, rplen); 559 if (ah == NULL) { 560 DPRINTF(("ah_input: cannot pullup header\n")); 561 AHSTAT_INC(ahs_hdrops); /*XXX*/ 562 error = ENOBUFS; 563 goto bad; 564 } 565 566 /* Check replay window, if applicable. */ 567 SECASVAR_LOCK(sav); 568 if (sav->replay != NULL && sav->replay->wsize != 0 && 569 ipsec_chkreplay(ntohl(ah->ah_seq), sav) == 0) { 570 SECASVAR_UNLOCK(sav); 571 AHSTAT_INC(ahs_replay); 572 DPRINTF(("%s: packet replay failure: %s\n", __func__, 573 ipsec_sa2str(sav, buf, sizeof(buf)))); 574 error = EACCES; 575 goto bad; 576 } 577 cryptoid = sav->tdb_cryptoid; 578 SECASVAR_UNLOCK(sav); 579 580 /* Verify AH header length. */ 581 hl = sizeof(struct ah) + (ah->ah_len * sizeof (u_int32_t)); 582 ahx = sav->tdb_authalgxform; 583 authsize = AUTHSIZE(sav); 584 ahsize = ah_hdrsiz(sav); 585 if (hl != ahsize) { 586 DPRINTF(("%s: bad authenticator length %u (expecting %lu)" 587 " for packet in SA %s/%08lx\n", __func__, hl, 588 (u_long)ahsize, 589 ipsec_address(&sav->sah->saidx.dst, buf, sizeof(buf)), 590 (u_long) ntohl(sav->spi))); 591 AHSTAT_INC(ahs_badauthl); 592 error = EACCES; 593 goto bad; 594 } 595 if (skip + ahsize > m->m_pkthdr.len) { 596 DPRINTF(("%s: bad mbuf length %u (expecting %lu)" 597 " for packet in SA %s/%08lx\n", __func__, 598 m->m_pkthdr.len, (u_long)(skip + ahsize), 599 ipsec_address(&sav->sah->saidx.dst, buf, sizeof(buf)), 600 (u_long) ntohl(sav->spi))); 601 AHSTAT_INC(ahs_badauthl); 602 error = EACCES; 603 goto bad; 604 } 605 AHSTAT_ADD(ahs_ibytes, m->m_pkthdr.len - skip - hl); 606 607 /* Get crypto descriptors. */ 608 crp = crypto_getreq(1); 609 if (crp == NULL) { 610 DPRINTF(("%s: failed to acquire crypto descriptor\n", 611 __func__)); 612 AHSTAT_INC(ahs_crypto); 613 error = ENOBUFS; 614 goto bad; 615 } 616 617 crda = crp->crp_desc; 618 IPSEC_ASSERT(crda != NULL, ("null crypto descriptor")); 619 620 crda->crd_skip = 0; 621 crda->crd_len = m->m_pkthdr.len; 622 crda->crd_inject = skip + rplen; 623 624 /* Authentication operation. */ 625 crda->crd_alg = ahx->type; 626 crda->crd_klen = _KEYBITS(sav->key_auth); 627 crda->crd_key = sav->key_auth->key_data; 628 629 /* Allocate IPsec-specific opaque crypto info. */ 630 xd = malloc(sizeof(*xd) + skip + rplen + authsize, M_XDATA, 631 M_NOWAIT | M_ZERO); 632 if (xd == NULL) { 633 DPRINTF(("%s: failed to allocate xform_data\n", __func__)); 634 AHSTAT_INC(ahs_crypto); 635 crypto_freereq(crp); 636 error = ENOBUFS; 637 goto bad; 638 } 639 640 /* 641 * Save the authenticator, the skipped portion of the packet, 642 * and the AH header. 643 */ 644 m_copydata(m, 0, skip + rplen + authsize, (caddr_t)(xd + 1)); 645 646 /* Zeroize the authenticator on the packet. */ 647 m_copyback(m, skip + rplen, authsize, ipseczeroes); 648 649 /* Save ah_nxt, since ah pointer can become invalid after "massage" */ 650 hl = ah->ah_nxt; 651 652 /* "Massage" the packet headers for crypto processing. */ 653 error = ah_massage_headers(&m, sav->sah->saidx.dst.sa.sa_family, 654 skip, ahx->type, 0); 655 if (error != 0) { 656 /* NB: mbuf is free'd by ah_massage_headers */ 657 AHSTAT_INC(ahs_hdrops); 658 free(xd, M_XDATA); 659 crypto_freereq(crp); 660 key_freesav(&sav); 661 return (error); 662 } 663 664 /* Crypto operation descriptor. */ 665 crp->crp_ilen = m->m_pkthdr.len; /* Total input length. */ 666 crp->crp_flags = CRYPTO_F_IMBUF | CRYPTO_F_CBIFSYNC; 667 if (V_async_crypto) 668 crp->crp_flags |= CRYPTO_F_ASYNC | CRYPTO_F_ASYNC_KEEPORDER; 669 crp->crp_buf = (caddr_t) m; 670 crp->crp_callback = ah_input_cb; 671 crp->crp_session = cryptoid; 672 crp->crp_opaque = (caddr_t) xd; 673 674 /* These are passed as-is to the callback. */ 675 xd->sav = sav; 676 xd->nxt = hl; 677 xd->protoff = protoff; 678 xd->skip = skip; 679 xd->cryptoid = cryptoid; 680 xd->vnet = curvnet; 681 return (crypto_dispatch(crp)); 682 bad: 683 m_freem(m); 684 key_freesav(&sav); 685 return (error); 686 } 687 688 /* 689 * AH input callback from the crypto driver. 690 */ 691 static int 692 ah_input_cb(struct cryptop *crp) 693 { 694 IPSEC_DEBUG_DECLARE(char buf[IPSEC_ADDRSTRLEN]); 695 unsigned char calc[AH_ALEN_MAX]; 696 struct mbuf *m; 697 struct xform_data *xd; 698 struct secasvar *sav; 699 struct secasindex *saidx; 700 caddr_t ptr; 701 crypto_session_t cryptoid; 702 int authsize, rplen, ahsize, error, skip, protoff; 703 uint8_t nxt; 704 705 m = (struct mbuf *) crp->crp_buf; 706 xd = (struct xform_data *) crp->crp_opaque; 707 CURVNET_SET(xd->vnet); 708 sav = xd->sav; 709 skip = xd->skip; 710 nxt = xd->nxt; 711 protoff = xd->protoff; 712 cryptoid = xd->cryptoid; 713 saidx = &sav->sah->saidx; 714 IPSEC_ASSERT(saidx->dst.sa.sa_family == AF_INET || 715 saidx->dst.sa.sa_family == AF_INET6, 716 ("unexpected protocol family %u", saidx->dst.sa.sa_family)); 717 718 /* Check for crypto errors. */ 719 if (crp->crp_etype) { 720 if (crp->crp_etype == EAGAIN) { 721 /* Reset the session ID */ 722 if (ipsec_updateid(sav, &crp->crp_session, &cryptoid) != 0) 723 crypto_freesession(cryptoid); 724 xd->cryptoid = crp->crp_session; 725 CURVNET_RESTORE(); 726 return (crypto_dispatch(crp)); 727 } 728 AHSTAT_INC(ahs_noxform); 729 DPRINTF(("%s: crypto error %d\n", __func__, crp->crp_etype)); 730 error = crp->crp_etype; 731 goto bad; 732 } else { 733 AHSTAT_INC(ahs_hist[sav->alg_auth]); 734 crypto_freereq(crp); /* No longer needed. */ 735 crp = NULL; 736 } 737 738 /* Shouldn't happen... */ 739 if (m == NULL) { 740 AHSTAT_INC(ahs_crypto); 741 DPRINTF(("%s: bogus returned buffer from crypto\n", __func__)); 742 error = EINVAL; 743 goto bad; 744 } 745 746 /* Figure out header size. */ 747 rplen = HDRSIZE(sav); 748 authsize = AUTHSIZE(sav); 749 ahsize = ah_hdrsiz(sav); 750 751 /* Copy authenticator off the packet. */ 752 m_copydata(m, skip + rplen, authsize, calc); 753 754 /* Verify authenticator. */ 755 ptr = (caddr_t) (xd + 1); 756 if (timingsafe_bcmp(ptr + skip + rplen, calc, authsize)) { 757 DPRINTF(("%s: authentication hash mismatch for packet " 758 "in SA %s/%08lx\n", __func__, 759 ipsec_address(&saidx->dst, buf, sizeof(buf)), 760 (u_long) ntohl(sav->spi))); 761 AHSTAT_INC(ahs_badauth); 762 error = EACCES; 763 goto bad; 764 } 765 /* Fix the Next Protocol field. */ 766 ((uint8_t *) ptr)[protoff] = nxt; 767 768 /* Copyback the saved (uncooked) network headers. */ 769 m_copyback(m, 0, skip, ptr); 770 free(xd, M_XDATA), xd = NULL; /* No longer needed */ 771 772 /* 773 * Header is now authenticated. 774 */ 775 m->m_flags |= M_AUTHIPHDR|M_AUTHIPDGM; 776 777 /* 778 * Update replay sequence number, if appropriate. 779 */ 780 if (sav->replay) { 781 u_int32_t seq; 782 783 m_copydata(m, skip + offsetof(struct newah, ah_seq), 784 sizeof (seq), (caddr_t) &seq); 785 SECASVAR_LOCK(sav); 786 if (ipsec_updatereplay(ntohl(seq), sav)) { 787 SECASVAR_UNLOCK(sav); 788 AHSTAT_INC(ahs_replay); 789 error = EACCES; 790 goto bad; 791 } 792 SECASVAR_UNLOCK(sav); 793 } 794 795 /* 796 * Remove the AH header and authenticator from the mbuf. 797 */ 798 error = m_striphdr(m, skip, ahsize); 799 if (error) { 800 DPRINTF(("%s: mangled mbuf chain for SA %s/%08lx\n", __func__, 801 ipsec_address(&saidx->dst, buf, sizeof(buf)), 802 (u_long) ntohl(sav->spi))); 803 AHSTAT_INC(ahs_hdrops); 804 goto bad; 805 } 806 807 switch (saidx->dst.sa.sa_family) { 808 #ifdef INET6 809 case AF_INET6: 810 error = ipsec6_common_input_cb(m, sav, skip, protoff); 811 break; 812 #endif 813 #ifdef INET 814 case AF_INET: 815 error = ipsec4_common_input_cb(m, sav, skip, protoff); 816 break; 817 #endif 818 default: 819 panic("%s: Unexpected address family: %d saidx=%p", __func__, 820 saidx->dst.sa.sa_family, saidx); 821 } 822 CURVNET_RESTORE(); 823 return error; 824 bad: 825 CURVNET_RESTORE(); 826 if (sav) 827 key_freesav(&sav); 828 if (m != NULL) 829 m_freem(m); 830 if (xd != NULL) 831 free(xd, M_XDATA); 832 if (crp != NULL) 833 crypto_freereq(crp); 834 return error; 835 } 836 837 /* 838 * AH output routine, called by ipsec[46]_perform_request(). 839 */ 840 static int 841 ah_output(struct mbuf *m, struct secpolicy *sp, struct secasvar *sav, 842 u_int idx, int skip, int protoff) 843 { 844 IPSEC_DEBUG_DECLARE(char buf[IPSEC_ADDRSTRLEN]); 845 const struct auth_hash *ahx; 846 struct cryptodesc *crda; 847 struct xform_data *xd; 848 struct mbuf *mi; 849 struct cryptop *crp; 850 struct newah *ah; 851 crypto_session_t cryptoid; 852 uint16_t iplen; 853 int error, rplen, authsize, ahsize, maxpacketsize, roff; 854 uint8_t prot; 855 856 IPSEC_ASSERT(sav != NULL, ("null SA")); 857 ahx = sav->tdb_authalgxform; 858 IPSEC_ASSERT(ahx != NULL, ("null authentication xform")); 859 860 AHSTAT_INC(ahs_output); 861 862 /* Figure out header size. */ 863 rplen = HDRSIZE(sav); 864 authsize = AUTHSIZE(sav); 865 ahsize = ah_hdrsiz(sav); 866 867 /* Check for maximum packet size violations. */ 868 switch (sav->sah->saidx.dst.sa.sa_family) { 869 #ifdef INET 870 case AF_INET: 871 maxpacketsize = IP_MAXPACKET; 872 break; 873 #endif /* INET */ 874 #ifdef INET6 875 case AF_INET6: 876 maxpacketsize = IPV6_MAXPACKET; 877 break; 878 #endif /* INET6 */ 879 default: 880 DPRINTF(("%s: unknown/unsupported protocol family %u, " 881 "SA %s/%08lx\n", __func__, 882 sav->sah->saidx.dst.sa.sa_family, 883 ipsec_address(&sav->sah->saidx.dst, buf, sizeof(buf)), 884 (u_long) ntohl(sav->spi))); 885 AHSTAT_INC(ahs_nopf); 886 error = EPFNOSUPPORT; 887 goto bad; 888 } 889 if (ahsize + m->m_pkthdr.len > maxpacketsize) { 890 DPRINTF(("%s: packet in SA %s/%08lx got too big " 891 "(len %u, max len %u)\n", __func__, 892 ipsec_address(&sav->sah->saidx.dst, buf, sizeof(buf)), 893 (u_long) ntohl(sav->spi), 894 ahsize + m->m_pkthdr.len, maxpacketsize)); 895 AHSTAT_INC(ahs_toobig); 896 error = EMSGSIZE; 897 goto bad; 898 } 899 900 /* Update the counters. */ 901 AHSTAT_ADD(ahs_obytes, m->m_pkthdr.len - skip); 902 903 m = m_unshare(m, M_NOWAIT); 904 if (m == NULL) { 905 DPRINTF(("%s: cannot clone mbuf chain, SA %s/%08lx\n", __func__, 906 ipsec_address(&sav->sah->saidx.dst, buf, sizeof(buf)), 907 (u_long) ntohl(sav->spi))); 908 AHSTAT_INC(ahs_hdrops); 909 error = ENOBUFS; 910 goto bad; 911 } 912 913 /* Inject AH header. */ 914 mi = m_makespace(m, skip, ahsize, &roff); 915 if (mi == NULL) { 916 DPRINTF(("%s: failed to inject %u byte AH header for SA " 917 "%s/%08lx\n", __func__, ahsize, 918 ipsec_address(&sav->sah->saidx.dst, buf, sizeof(buf)), 919 (u_long) ntohl(sav->spi))); 920 AHSTAT_INC(ahs_hdrops); /*XXX differs from openbsd */ 921 error = ENOBUFS; 922 goto bad; 923 } 924 925 /* 926 * The AH header is guaranteed by m_makespace() to be in 927 * contiguous memory, at roff bytes offset into the returned mbuf. 928 */ 929 ah = (struct newah *)(mtod(mi, caddr_t) + roff); 930 931 /* Initialize the AH header. */ 932 m_copydata(m, protoff, sizeof(u_int8_t), (caddr_t) &ah->ah_nxt); 933 ah->ah_len = (ahsize - sizeof(struct ah)) / sizeof(u_int32_t); 934 ah->ah_reserve = 0; 935 ah->ah_spi = sav->spi; 936 937 /* Zeroize authenticator. */ 938 m_copyback(m, skip + rplen, authsize, ipseczeroes); 939 940 /* Zeroize padding */ 941 m_copyback(m, skip + rplen + authsize, ahsize - (rplen + authsize), 942 ipseczeroes); 943 944 /* Insert packet replay counter, as requested. */ 945 SECASVAR_LOCK(sav); 946 if (sav->replay) { 947 if (sav->replay->count == ~0 && 948 (sav->flags & SADB_X_EXT_CYCSEQ) == 0) { 949 SECASVAR_UNLOCK(sav); 950 DPRINTF(("%s: replay counter wrapped for SA %s/%08lx\n", 951 __func__, ipsec_address(&sav->sah->saidx.dst, buf, 952 sizeof(buf)), (u_long) ntohl(sav->spi))); 953 AHSTAT_INC(ahs_wrap); 954 error = EACCES; 955 goto bad; 956 } 957 #ifdef REGRESSION 958 /* Emulate replay attack when ipsec_replay is TRUE. */ 959 if (!V_ipsec_replay) 960 #endif 961 sav->replay->count++; 962 ah->ah_seq = htonl(sav->replay->count); 963 } 964 cryptoid = sav->tdb_cryptoid; 965 SECASVAR_UNLOCK(sav); 966 967 /* Get crypto descriptors. */ 968 crp = crypto_getreq(1); 969 if (crp == NULL) { 970 DPRINTF(("%s: failed to acquire crypto descriptors\n", 971 __func__)); 972 AHSTAT_INC(ahs_crypto); 973 error = ENOBUFS; 974 goto bad; 975 } 976 977 crda = crp->crp_desc; 978 crda->crd_skip = 0; 979 crda->crd_inject = skip + rplen; 980 crda->crd_len = m->m_pkthdr.len; 981 982 /* Authentication operation. */ 983 crda->crd_alg = ahx->type; 984 crda->crd_key = sav->key_auth->key_data; 985 crda->crd_klen = _KEYBITS(sav->key_auth); 986 987 /* Allocate IPsec-specific opaque crypto info. */ 988 xd = malloc(sizeof(struct xform_data) + skip, M_XDATA, 989 M_NOWAIT | M_ZERO); 990 if (xd == NULL) { 991 crypto_freereq(crp); 992 DPRINTF(("%s: failed to allocate xform_data\n", __func__)); 993 AHSTAT_INC(ahs_crypto); 994 error = ENOBUFS; 995 goto bad; 996 } 997 998 /* Save the skipped portion of the packet. */ 999 m_copydata(m, 0, skip, (caddr_t) (xd + 1)); 1000 1001 /* 1002 * Fix IP header length on the header used for 1003 * authentication. We don't need to fix the original 1004 * header length as it will be fixed by our caller. 1005 */ 1006 switch (sav->sah->saidx.dst.sa.sa_family) { 1007 #ifdef INET 1008 case AF_INET: 1009 bcopy(((caddr_t)(xd + 1)) + 1010 offsetof(struct ip, ip_len), 1011 (caddr_t) &iplen, sizeof(u_int16_t)); 1012 iplen = htons(ntohs(iplen) + ahsize); 1013 m_copyback(m, offsetof(struct ip, ip_len), 1014 sizeof(u_int16_t), (caddr_t) &iplen); 1015 break; 1016 #endif /* INET */ 1017 1018 #ifdef INET6 1019 case AF_INET6: 1020 bcopy(((caddr_t)(xd + 1)) + 1021 offsetof(struct ip6_hdr, ip6_plen), 1022 (caddr_t) &iplen, sizeof(uint16_t)); 1023 iplen = htons(ntohs(iplen) + ahsize); 1024 m_copyback(m, offsetof(struct ip6_hdr, ip6_plen), 1025 sizeof(uint16_t), (caddr_t) &iplen); 1026 break; 1027 #endif /* INET6 */ 1028 } 1029 1030 /* Fix the Next Header field in saved header. */ 1031 ((uint8_t *) (xd + 1))[protoff] = IPPROTO_AH; 1032 1033 /* Update the Next Protocol field in the IP header. */ 1034 prot = IPPROTO_AH; 1035 m_copyback(m, protoff, sizeof(uint8_t), (caddr_t) &prot); 1036 1037 /* "Massage" the packet headers for crypto processing. */ 1038 error = ah_massage_headers(&m, sav->sah->saidx.dst.sa.sa_family, 1039 skip, ahx->type, 1); 1040 if (error != 0) { 1041 m = NULL; /* mbuf was free'd by ah_massage_headers. */ 1042 free(xd, M_XDATA); 1043 crypto_freereq(crp); 1044 goto bad; 1045 } 1046 1047 /* Crypto operation descriptor. */ 1048 crp->crp_ilen = m->m_pkthdr.len; /* Total input length. */ 1049 crp->crp_flags = CRYPTO_F_IMBUF | CRYPTO_F_CBIFSYNC; 1050 if (V_async_crypto) 1051 crp->crp_flags |= CRYPTO_F_ASYNC | CRYPTO_F_ASYNC_KEEPORDER; 1052 crp->crp_buf = (caddr_t) m; 1053 crp->crp_callback = ah_output_cb; 1054 crp->crp_session = cryptoid; 1055 crp->crp_opaque = (caddr_t) xd; 1056 1057 /* These are passed as-is to the callback. */ 1058 xd->sp = sp; 1059 xd->sav = sav; 1060 xd->skip = skip; 1061 xd->idx = idx; 1062 xd->cryptoid = cryptoid; 1063 xd->vnet = curvnet; 1064 1065 return crypto_dispatch(crp); 1066 bad: 1067 if (m) 1068 m_freem(m); 1069 key_freesav(&sav); 1070 key_freesp(&sp); 1071 return (error); 1072 } 1073 1074 /* 1075 * AH output callback from the crypto driver. 1076 */ 1077 static int 1078 ah_output_cb(struct cryptop *crp) 1079 { 1080 struct xform_data *xd; 1081 struct secpolicy *sp; 1082 struct secasvar *sav; 1083 struct mbuf *m; 1084 crypto_session_t cryptoid; 1085 caddr_t ptr; 1086 u_int idx; 1087 int skip, error; 1088 1089 m = (struct mbuf *) crp->crp_buf; 1090 xd = (struct xform_data *) crp->crp_opaque; 1091 CURVNET_SET(xd->vnet); 1092 sp = xd->sp; 1093 sav = xd->sav; 1094 skip = xd->skip; 1095 idx = xd->idx; 1096 cryptoid = xd->cryptoid; 1097 ptr = (caddr_t) (xd + 1); 1098 1099 /* Check for crypto errors. */ 1100 if (crp->crp_etype) { 1101 if (crp->crp_etype == EAGAIN) { 1102 /* Reset the session ID */ 1103 if (ipsec_updateid(sav, &crp->crp_session, &cryptoid) != 0) 1104 crypto_freesession(cryptoid); 1105 xd->cryptoid = crp->crp_session; 1106 CURVNET_RESTORE(); 1107 return (crypto_dispatch(crp)); 1108 } 1109 AHSTAT_INC(ahs_noxform); 1110 DPRINTF(("%s: crypto error %d\n", __func__, crp->crp_etype)); 1111 error = crp->crp_etype; 1112 m_freem(m); 1113 goto bad; 1114 } 1115 1116 /* Shouldn't happen... */ 1117 if (m == NULL) { 1118 AHSTAT_INC(ahs_crypto); 1119 DPRINTF(("%s: bogus returned buffer from crypto\n", __func__)); 1120 error = EINVAL; 1121 goto bad; 1122 } 1123 /* 1124 * Copy original headers (with the new protocol number) back 1125 * in place. 1126 */ 1127 m_copyback(m, 0, skip, ptr); 1128 1129 free(xd, M_XDATA); 1130 crypto_freereq(crp); 1131 AHSTAT_INC(ahs_hist[sav->alg_auth]); 1132 #ifdef REGRESSION 1133 /* Emulate man-in-the-middle attack when ipsec_integrity is TRUE. */ 1134 if (V_ipsec_integrity) { 1135 int alen; 1136 1137 /* 1138 * Corrupt HMAC if we want to test integrity verification of 1139 * the other side. 1140 */ 1141 alen = AUTHSIZE(sav); 1142 m_copyback(m, m->m_pkthdr.len - alen, alen, ipseczeroes); 1143 } 1144 #endif 1145 1146 /* NB: m is reclaimed by ipsec_process_done. */ 1147 error = ipsec_process_done(m, sp, sav, idx); 1148 CURVNET_RESTORE(); 1149 return (error); 1150 bad: 1151 CURVNET_RESTORE(); 1152 free(xd, M_XDATA); 1153 crypto_freereq(crp); 1154 key_freesav(&sav); 1155 key_freesp(&sp); 1156 return (error); 1157 } 1158 1159 static struct xformsw ah_xformsw = { 1160 .xf_type = XF_AH, 1161 .xf_name = "IPsec AH", 1162 .xf_init = ah_init, 1163 .xf_zeroize = ah_zeroize, 1164 .xf_input = ah_input, 1165 .xf_output = ah_output, 1166 }; 1167 1168 SYSINIT(ah_xform_init, SI_SUB_PROTO_DOMAIN, SI_ORDER_MIDDLE, 1169 xform_attach, &ah_xformsw); 1170 SYSUNINIT(ah_xform_uninit, SI_SUB_PROTO_DOMAIN, SI_ORDER_MIDDLE, 1171 xform_detach, &ah_xformsw); 1172