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 #include "opt_ipsec.h" 42 43 #include <sys/param.h> 44 #include <sys/systm.h> 45 #include <sys/malloc.h> 46 #include <sys/mbuf.h> 47 #include <sys/socket.h> 48 #include <sys/syslog.h> 49 #include <sys/kernel.h> 50 #include <sys/lock.h> 51 #include <sys/mutex.h> 52 #include <sys/sysctl.h> 53 54 #include <net/if.h> 55 #include <net/vnet.h> 56 57 #include <netinet/in.h> 58 #include <netinet/in_systm.h> 59 #include <netinet/ip.h> 60 #include <netinet/ip_ecn.h> 61 #include <netinet/ip6.h> 62 63 #include <netipsec/ipsec.h> 64 #include <netipsec/ah.h> 65 #include <netipsec/ah_var.h> 66 #include <netipsec/xform.h> 67 68 #ifdef INET6 69 #include <netinet6/ip6_var.h> 70 #include <netipsec/ipsec6.h> 71 #include <netinet6/ip6_ecn.h> 72 #endif 73 74 #include <netipsec/key.h> 75 #include <netipsec/key_debug.h> 76 77 #include <opencrypto/cryptodev.h> 78 79 /* 80 * Return header size in bytes. The old protocol did not support 81 * the replay counter; the new protocol always includes the counter. 82 */ 83 #define HDRSIZE(sav) \ 84 (((sav)->flags & SADB_X_EXT_OLD) ? \ 85 sizeof (struct ah) : sizeof (struct ah) + sizeof (u_int32_t)) 86 /* 87 * Return authenticator size in bytes, based on a field in the 88 * algorithm descriptor. 89 */ 90 #define AUTHSIZE(sav) ((sav->flags & SADB_X_EXT_OLD) ? 16 : \ 91 xform_ah_authsize((sav)->tdb_authalgxform)) 92 93 VNET_DEFINE(int, ah_enable) = 1; /* control flow of packets with AH */ 94 VNET_DEFINE(int, ah_cleartos) = 1; /* clear ip_tos when doing AH calc */ 95 VNET_PCPUSTAT_DEFINE(struct ahstat, ahstat); 96 VNET_PCPUSTAT_SYSINIT(ahstat); 97 98 #ifdef VIMAGE 99 VNET_PCPUSTAT_SYSUNINIT(ahstat); 100 #endif /* VIMAGE */ 101 102 #ifdef INET 103 SYSCTL_DECL(_net_inet_ah); 104 SYSCTL_INT(_net_inet_ah, OID_AUTO, ah_enable, 105 CTLFLAG_VNET | CTLFLAG_RW, &VNET_NAME(ah_enable), 0, ""); 106 SYSCTL_INT(_net_inet_ah, OID_AUTO, ah_cleartos, 107 CTLFLAG_VNET | CTLFLAG_RW, &VNET_NAME(ah_cleartos), 0, ""); 108 SYSCTL_VNET_PCPUSTAT(_net_inet_ah, IPSECCTL_STATS, stats, struct ahstat, 109 ahstat, "AH statistics (struct ahstat, netipsec/ah_var.h)"); 110 #endif 111 112 static MALLOC_DEFINE(M_AH, "ah", "IPsec AH"); 113 114 static unsigned char ipseczeroes[256]; /* larger than an ip6 extension hdr */ 115 116 static int ah_input_cb(struct cryptop*); 117 static int ah_output_cb(struct cryptop*); 118 119 int 120 xform_ah_authsize(const struct auth_hash *esph) 121 { 122 int alen; 123 124 if (esph == NULL) 125 return 0; 126 127 switch (esph->type) { 128 case CRYPTO_SHA2_256_HMAC: 129 case CRYPTO_SHA2_384_HMAC: 130 case CRYPTO_SHA2_512_HMAC: 131 alen = esph->hashsize / 2; /* RFC4868 2.3 */ 132 break; 133 134 case CRYPTO_AES_NIST_GMAC: 135 alen = esph->hashsize; 136 break; 137 138 default: 139 alen = AH_HMAC_HASHLEN; 140 break; 141 } 142 143 return alen; 144 } 145 146 size_t 147 ah_hdrsiz(struct secasvar *sav) 148 { 149 size_t size; 150 151 if (sav != NULL) { 152 int authsize, rplen, align; 153 154 IPSEC_ASSERT(sav->tdb_authalgxform != NULL, ("null xform")); 155 /*XXX not right for null algorithm--does it matter??*/ 156 157 /* RFC4302: use the correct alignment. */ 158 align = sizeof(uint32_t); 159 #ifdef INET6 160 if (sav->sah->saidx.dst.sa.sa_family == AF_INET6) { 161 align = sizeof(uint64_t); 162 } 163 #endif 164 rplen = HDRSIZE(sav); 165 authsize = AUTHSIZE(sav); 166 size = roundup(rplen + authsize, align); 167 } else { 168 /* default guess */ 169 size = sizeof (struct ah) + sizeof (u_int32_t) + 16; 170 } 171 return size; 172 } 173 174 /* 175 * NB: public for use by esp_init. 176 */ 177 int 178 ah_init0(struct secasvar *sav, struct xformsw *xsp, 179 struct crypto_session_params *csp) 180 { 181 const struct auth_hash *thash; 182 int keylen; 183 184 thash = auth_algorithm_lookup(sav->alg_auth); 185 if (thash == NULL) { 186 DPRINTF(("%s: unsupported authentication algorithm %u\n", 187 __func__, sav->alg_auth)); 188 return EINVAL; 189 } 190 191 /* 192 * Verify the replay state block allocation is consistent with 193 * the protocol type. We check here so we can make assumptions 194 * later during protocol processing. 195 */ 196 /* NB: replay state is setup elsewhere (sigh) */ 197 if (((sav->flags&SADB_X_EXT_OLD) == 0) ^ (sav->replay != NULL)) { 198 DPRINTF(("%s: replay state block inconsistency, " 199 "%s algorithm %s replay state\n", __func__, 200 (sav->flags & SADB_X_EXT_OLD) ? "old" : "new", 201 sav->replay == NULL ? "without" : "with")); 202 return EINVAL; 203 } 204 if (sav->key_auth == NULL) { 205 DPRINTF(("%s: no authentication key for %s algorithm\n", 206 __func__, thash->name)); 207 return EINVAL; 208 } 209 keylen = _KEYLEN(sav->key_auth); 210 if (keylen > thash->keysize && thash->keysize != 0) { 211 DPRINTF(("%s: invalid keylength %d, algorithm %s requires " 212 "keysize less than %d\n", __func__, 213 keylen, thash->name, thash->keysize)); 214 return EINVAL; 215 } 216 217 sav->tdb_xform = xsp; 218 sav->tdb_authalgxform = thash; 219 220 /* Initialize crypto session. */ 221 csp->csp_auth_alg = sav->tdb_authalgxform->type; 222 if (csp->csp_auth_alg != CRYPTO_NULL_HMAC) { 223 csp->csp_auth_klen = _KEYBITS(sav->key_auth) / 8; 224 csp->csp_auth_key = sav->key_auth->key_data; 225 }; 226 csp->csp_auth_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 crypto_session_params csp; 238 int error; 239 240 memset(&csp, 0, sizeof(csp)); 241 csp.csp_mode = CSP_MODE_DIGEST; 242 243 if (sav->flags & SADB_X_SAFLAGS_ESN) 244 csp.csp_flags |= CSP_F_ESN; 245 246 error = ah_init0(sav, xsp, &csp); 247 return error ? error : 248 crypto_newsession(&sav->tdb_cryptoid, &csp, V_crypto_support); 249 } 250 251 static void 252 ah_cleanup(struct secasvar *sav) 253 { 254 255 crypto_freesession(sav->tdb_cryptoid); 256 sav->tdb_cryptoid = NULL; 257 sav->tdb_authalgxform = NULL; 258 } 259 260 /* 261 * Massage IPv4/IPv6 headers for AH processing. 262 */ 263 static int 264 ah_massage_headers(struct mbuf **m0, int proto, int skip, int alg, int out) 265 { 266 struct mbuf *m = *m0; 267 unsigned char *ptr; 268 int off, count; 269 270 #ifdef INET 271 struct ip *ip; 272 #endif /* INET */ 273 274 #ifdef INET6 275 struct ip6_ext *ip6e; 276 struct ip6_hdr ip6; 277 int ad, alloc, nxt, noff; 278 #endif /* INET6 */ 279 280 switch (proto) { 281 #ifdef INET 282 case AF_INET: 283 /* 284 * This is the least painful way of dealing with IPv4 header 285 * and option processing -- just make sure they're in 286 * contiguous memory. 287 */ 288 *m0 = m = m_pullup(m, skip); 289 if (m == NULL) { 290 DPRINTF(("%s: m_pullup failed\n", __func__)); 291 return ENOBUFS; 292 } 293 294 /* Fix the IP header */ 295 ip = mtod(m, struct ip *); 296 if (V_ah_cleartos) 297 ip->ip_tos = 0; 298 ip->ip_ttl = 0; 299 ip->ip_sum = 0; 300 ip->ip_off = htons(0); 301 302 ptr = mtod(m, unsigned char *); 303 304 /* IPv4 option processing */ 305 for (off = sizeof(struct ip); off < skip;) { 306 if (ptr[off] == IPOPT_EOL || ptr[off] == IPOPT_NOP || 307 off + 1 < skip) 308 ; 309 else { 310 DPRINTF(("%s: illegal IPv4 option length for " 311 "option %d\n", __func__, ptr[off])); 312 313 m_freem(m); 314 return EINVAL; 315 } 316 317 switch (ptr[off]) { 318 case IPOPT_EOL: 319 off = skip; /* End the loop. */ 320 break; 321 322 case IPOPT_NOP: 323 off++; 324 break; 325 326 case IPOPT_SECURITY: /* 0x82 */ 327 case 0x85: /* Extended security. */ 328 case 0x86: /* Commercial security. */ 329 case 0x94: /* Router alert */ 330 case 0x95: /* RFC1770 */ 331 /* Sanity check for option length. */ 332 if (ptr[off + 1] < 2) { 333 DPRINTF(("%s: illegal IPv4 option " 334 "length for option %d\n", 335 __func__, ptr[off])); 336 337 m_freem(m); 338 return EINVAL; 339 } 340 341 off += ptr[off + 1]; 342 break; 343 344 case IPOPT_LSRR: 345 case IPOPT_SSRR: 346 /* Sanity check for option length. */ 347 if (ptr[off + 1] < 2) { 348 DPRINTF(("%s: illegal IPv4 option " 349 "length for option %d\n", 350 __func__, ptr[off])); 351 352 m_freem(m); 353 return EINVAL; 354 } 355 356 /* 357 * On output, if we have either of the 358 * source routing options, we should 359 * swap the destination address of the 360 * IP header with the last address 361 * specified in the option, as that is 362 * what the destination's IP header 363 * will look like. 364 */ 365 if (out) 366 bcopy(ptr + off + ptr[off + 1] - 367 sizeof(struct in_addr), 368 &(ip->ip_dst), sizeof(struct in_addr)); 369 370 /* Fall through */ 371 default: 372 /* Sanity check for option length. */ 373 if (ptr[off + 1] < 2) { 374 DPRINTF(("%s: illegal IPv4 option " 375 "length for option %d\n", 376 __func__, ptr[off])); 377 m_freem(m); 378 return EINVAL; 379 } 380 381 /* Zeroize all other options. */ 382 count = ptr[off + 1]; 383 bcopy(ipseczeroes, ptr + off, count); 384 off += count; 385 break; 386 } 387 388 /* Sanity check. */ 389 if (off > skip) { 390 DPRINTF(("%s: malformed IPv4 options header\n", 391 __func__)); 392 393 m_freem(m); 394 return EINVAL; 395 } 396 } 397 398 break; 399 #endif /* INET */ 400 401 #ifdef INET6 402 case AF_INET6: /* Ugly... */ 403 /* Copy and "cook" the IPv6 header. */ 404 m_copydata(m, 0, sizeof(ip6), (caddr_t) &ip6); 405 406 /* We don't do IPv6 Jumbograms. */ 407 if (ip6.ip6_plen == 0) { 408 DPRINTF(("%s: unsupported IPv6 jumbogram\n", __func__)); 409 m_freem(m); 410 return EMSGSIZE; 411 } 412 413 ip6.ip6_flow = 0; 414 ip6.ip6_hlim = 0; 415 ip6.ip6_vfc &= ~IPV6_VERSION_MASK; 416 ip6.ip6_vfc |= IPV6_VERSION; 417 418 /* Scoped address handling. */ 419 if (IN6_IS_SCOPE_LINKLOCAL(&ip6.ip6_src)) 420 ip6.ip6_src.s6_addr16[1] = 0; 421 if (IN6_IS_SCOPE_LINKLOCAL(&ip6.ip6_dst)) 422 ip6.ip6_dst.s6_addr16[1] = 0; 423 424 /* Done with IPv6 header. */ 425 m_copyback(m, 0, sizeof(struct ip6_hdr), (caddr_t) &ip6); 426 427 /* Let's deal with the remaining headers (if any). */ 428 if (skip - sizeof(struct ip6_hdr) > 0) { 429 if (m->m_len <= skip) { 430 ptr = (unsigned char *) malloc( 431 skip - sizeof(struct ip6_hdr), 432 M_AH, M_NOWAIT); 433 if (ptr == NULL) { 434 DPRINTF(("%s: failed to allocate memory" 435 "for IPv6 headers\n",__func__)); 436 m_freem(m); 437 return ENOBUFS; 438 } 439 440 /* 441 * Copy all the protocol headers after 442 * the IPv6 header. 443 */ 444 m_copydata(m, sizeof(struct ip6_hdr), 445 skip - sizeof(struct ip6_hdr), ptr); 446 alloc = 1; 447 } else { 448 /* No need to allocate memory. */ 449 ptr = mtod(m, unsigned char *) + 450 sizeof(struct ip6_hdr); 451 alloc = 0; 452 } 453 } else 454 break; 455 456 nxt = ip6.ip6_nxt & 0xff; /* Next header type. */ 457 458 for (off = 0; off < skip - sizeof(struct ip6_hdr);) 459 switch (nxt) { 460 case IPPROTO_HOPOPTS: 461 case IPPROTO_DSTOPTS: 462 ip6e = (struct ip6_ext *)(ptr + off); 463 noff = off + ((ip6e->ip6e_len + 1) << 3); 464 465 /* Sanity check. */ 466 if (noff > skip - sizeof(struct ip6_hdr)) 467 goto error6; 468 469 /* 470 * Zero out mutable options. 471 */ 472 for (count = off + sizeof(struct ip6_ext); 473 count < noff;) { 474 if (ptr[count] == IP6OPT_PAD1) { 475 count++; 476 continue; /* Skip padding. */ 477 } 478 479 ad = ptr[count + 1] + 2; 480 if (count + ad > noff) 481 goto error6; 482 483 if (ptr[count] & IP6OPT_MUTABLE) 484 memset(ptr + count, 0, ad); 485 count += ad; 486 } 487 488 if (count != noff) 489 goto error6; 490 491 /* Advance. */ 492 off += ((ip6e->ip6e_len + 1) << 3); 493 nxt = ip6e->ip6e_nxt; 494 break; 495 496 case IPPROTO_ROUTING: 497 /* 498 * Always include routing headers in 499 * computation. 500 */ 501 ip6e = (struct ip6_ext *) (ptr + off); 502 off += ((ip6e->ip6e_len + 1) << 3); 503 nxt = ip6e->ip6e_nxt; 504 break; 505 506 default: 507 DPRINTF(("%s: unexpected IPv6 header type %d", 508 __func__, off)); 509 error6: 510 if (alloc) 511 free(ptr, M_AH); 512 m_freem(m); 513 return EINVAL; 514 } 515 516 /* Copyback and free, if we allocated. */ 517 if (alloc) { 518 m_copyback(m, sizeof(struct ip6_hdr), 519 skip - sizeof(struct ip6_hdr), ptr); 520 free(ptr, M_AH); 521 } 522 523 break; 524 #endif /* INET6 */ 525 } 526 527 return 0; 528 } 529 530 /* 531 * ah_input() gets called to verify that an input packet 532 * passes authentication. 533 */ 534 static int 535 ah_input(struct mbuf *m, struct secasvar *sav, int skip, int protoff) 536 { 537 IPSEC_DEBUG_DECLARE(char buf[128]); 538 const struct auth_hash *ahx; 539 struct cryptop *crp; 540 struct xform_data *xd; 541 struct newah *ah; 542 crypto_session_t cryptoid; 543 int hl, rplen, authsize, ahsize, error; 544 uint32_t seqh; 545 546 IPSEC_ASSERT(sav != NULL, ("null SA")); 547 IPSEC_ASSERT(sav->key_auth != NULL, ("null authentication key")); 548 IPSEC_ASSERT(sav->tdb_authalgxform != NULL, 549 ("null authentication xform")); 550 551 /* Figure out header size. */ 552 rplen = HDRSIZE(sav); 553 554 if (m->m_len < skip + rplen) { 555 m = m_pullup(m, skip + rplen); 556 if (m == NULL) { 557 DPRINTF(("ah_input: cannot pullup header\n")); 558 AHSTAT_INC(ahs_hdrops); /*XXX*/ 559 error = ENOBUFS; 560 goto bad; 561 } 562 } 563 ah = (struct newah *)(mtod(m, caddr_t) + skip); 564 565 /* Check replay window, if applicable. */ 566 SECASVAR_LOCK(sav); 567 if (sav->replay != NULL && sav->replay->wsize != 0 && 568 ipsec_chkreplay(ntohl(ah->ah_seq), &seqh, sav) == 0) { 569 SECASVAR_UNLOCK(sav); 570 AHSTAT_INC(ahs_replay); 571 DPRINTF(("%s: packet replay failure: %s\n", __func__, 572 ipsec_sa2str(sav, buf, sizeof(buf)))); 573 error = EACCES; 574 goto bad; 575 } 576 cryptoid = sav->tdb_cryptoid; 577 SECASVAR_UNLOCK(sav); 578 579 /* Verify AH header length. */ 580 hl = sizeof(struct ah) + (ah->ah_len * sizeof (u_int32_t)); 581 ahx = sav->tdb_authalgxform; 582 authsize = AUTHSIZE(sav); 583 ahsize = ah_hdrsiz(sav); 584 if (hl != ahsize) { 585 DPRINTF(("%s: bad authenticator length %u (expecting %lu)" 586 " for packet in SA %s/%08lx\n", __func__, hl, 587 (u_long)ahsize, 588 ipsec_address(&sav->sah->saidx.dst, buf, sizeof(buf)), 589 (u_long) ntohl(sav->spi))); 590 AHSTAT_INC(ahs_badauthl); 591 error = EACCES; 592 goto bad; 593 } 594 if (skip + ahsize > m->m_pkthdr.len) { 595 DPRINTF(("%s: bad mbuf length %u (expecting %lu)" 596 " for packet in SA %s/%08lx\n", __func__, 597 m->m_pkthdr.len, (u_long)(skip + ahsize), 598 ipsec_address(&sav->sah->saidx.dst, buf, sizeof(buf)), 599 (u_long) ntohl(sav->spi))); 600 AHSTAT_INC(ahs_badauthl); 601 error = EACCES; 602 goto bad; 603 } 604 AHSTAT_ADD(ahs_ibytes, m->m_pkthdr.len - skip - hl); 605 606 /* Get crypto descriptors. */ 607 crp = crypto_getreq(cryptoid, M_NOWAIT); 608 if (crp == NULL) { 609 DPRINTF(("%s: failed to acquire crypto descriptor\n", 610 __func__)); 611 AHSTAT_INC(ahs_crypto); 612 error = ENOBUFS; 613 goto bad; 614 } 615 616 crp->crp_payload_start = 0; 617 crp->crp_payload_length = m->m_pkthdr.len; 618 crp->crp_digest_start = skip + rplen; 619 620 /* Allocate IPsec-specific opaque crypto info. */ 621 xd = malloc(sizeof(*xd) + skip + rplen + authsize, M_AH, 622 M_NOWAIT | M_ZERO); 623 if (xd == NULL) { 624 DPRINTF(("%s: failed to allocate xform_data\n", __func__)); 625 AHSTAT_INC(ahs_crypto); 626 crypto_freereq(crp); 627 error = ENOBUFS; 628 goto bad; 629 } 630 631 /* 632 * Save the authenticator, the skipped portion of the packet, 633 * and the AH header. 634 */ 635 m_copydata(m, 0, skip + rplen + authsize, (caddr_t)(xd + 1)); 636 637 /* Zeroize the authenticator on the packet. */ 638 m_copyback(m, skip + rplen, authsize, ipseczeroes); 639 640 /* Save ah_nxt, since ah pointer can become invalid after "massage" */ 641 hl = ah->ah_nxt; 642 643 /* "Massage" the packet headers for crypto processing. */ 644 error = ah_massage_headers(&m, sav->sah->saidx.dst.sa.sa_family, 645 skip, ahx->type, 0); 646 if (error != 0) { 647 /* NB: mbuf is free'd by ah_massage_headers */ 648 AHSTAT_INC(ahs_hdrops); 649 free(xd, M_AH); 650 crypto_freereq(crp); 651 key_freesav(&sav); 652 return (error); 653 } 654 655 /* Crypto operation descriptor. */ 656 crp->crp_op = CRYPTO_OP_COMPUTE_DIGEST; 657 crp->crp_flags = CRYPTO_F_CBIFSYNC; 658 crypto_use_mbuf(crp, m); 659 crp->crp_callback = ah_input_cb; 660 crp->crp_opaque = xd; 661 662 if (sav->flags & SADB_X_SAFLAGS_ESN && 663 sav->replay != NULL && sav->replay->wsize != 0) { 664 seqh = htonl(seqh); 665 memcpy(crp->crp_esn, &seqh, sizeof(seqh)); 666 } 667 668 /* These are passed as-is to the callback. */ 669 xd->sav = sav; 670 xd->nxt = hl; 671 xd->protoff = protoff; 672 xd->skip = skip; 673 xd->cryptoid = cryptoid; 674 xd->vnet = curvnet; 675 if (V_async_crypto) 676 return (crypto_dispatch_async(crp, CRYPTO_ASYNC_ORDERED)); 677 else 678 return (crypto_dispatch(crp)); 679 bad: 680 m_freem(m); 681 key_freesav(&sav); 682 return (error); 683 } 684 685 /* 686 * AH input callback from the crypto driver. 687 */ 688 static int 689 ah_input_cb(struct cryptop *crp) 690 { 691 IPSEC_DEBUG_DECLARE(char buf[IPSEC_ADDRSTRLEN]); 692 unsigned char calc[AH_ALEN_MAX]; 693 struct mbuf *m; 694 struct xform_data *xd; 695 struct secasvar *sav; 696 struct secasindex *saidx; 697 caddr_t ptr; 698 crypto_session_t cryptoid; 699 int authsize, rplen, ahsize, error, skip, protoff; 700 uint8_t nxt; 701 702 m = crp->crp_buf.cb_mbuf; 703 xd = crp->crp_opaque; 704 CURVNET_SET(xd->vnet); 705 sav = xd->sav; 706 skip = xd->skip; 707 nxt = xd->nxt; 708 protoff = xd->protoff; 709 cryptoid = xd->cryptoid; 710 saidx = &sav->sah->saidx; 711 IPSEC_ASSERT(saidx->dst.sa.sa_family == AF_INET || 712 saidx->dst.sa.sa_family == AF_INET6, 713 ("unexpected protocol family %u", saidx->dst.sa.sa_family)); 714 715 /* Check for crypto errors. */ 716 if (crp->crp_etype) { 717 if (crp->crp_etype == EAGAIN) { 718 /* Reset the session ID */ 719 if (ipsec_updateid(sav, &crp->crp_session, &cryptoid) != 0) 720 crypto_freesession(cryptoid); 721 xd->cryptoid = crp->crp_session; 722 CURVNET_RESTORE(); 723 return (crypto_dispatch(crp)); 724 } 725 AHSTAT_INC(ahs_noxform); 726 DPRINTF(("%s: crypto error %d\n", __func__, crp->crp_etype)); 727 error = crp->crp_etype; 728 goto bad; 729 } else { 730 AHSTAT_INC(ahs_hist[sav->alg_auth]); 731 crypto_freereq(crp); /* No longer needed. */ 732 crp = NULL; 733 } 734 735 /* Shouldn't happen... */ 736 if (m == NULL) { 737 AHSTAT_INC(ahs_crypto); 738 DPRINTF(("%s: bogus returned buffer from crypto\n", __func__)); 739 error = EINVAL; 740 goto bad; 741 } 742 743 /* Figure out header size. */ 744 rplen = HDRSIZE(sav); 745 authsize = AUTHSIZE(sav); 746 ahsize = ah_hdrsiz(sav); 747 748 /* Copy authenticator off the packet. */ 749 m_copydata(m, skip + rplen, authsize, calc); 750 751 /* Verify authenticator. */ 752 ptr = (caddr_t) (xd + 1); 753 if (timingsafe_bcmp(ptr + skip + rplen, calc, authsize)) { 754 DPRINTF(("%s: authentication hash mismatch for packet " 755 "in SA %s/%08lx\n", __func__, 756 ipsec_address(&saidx->dst, buf, sizeof(buf)), 757 (u_long) ntohl(sav->spi))); 758 AHSTAT_INC(ahs_badauth); 759 error = EACCES; 760 goto bad; 761 } 762 /* Fix the Next Protocol field. */ 763 ((uint8_t *) ptr)[protoff] = nxt; 764 765 /* Copyback the saved (uncooked) network headers. */ 766 m_copyback(m, 0, skip, ptr); 767 free(xd, M_AH), xd = NULL; /* No longer needed */ 768 769 /* 770 * Header is now authenticated. 771 */ 772 m->m_flags |= M_AUTHIPHDR|M_AUTHIPDGM; 773 774 /* 775 * Update replay sequence number, if appropriate. 776 */ 777 if (sav->replay) { 778 u_int32_t seq; 779 780 m_copydata(m, skip + offsetof(struct newah, ah_seq), 781 sizeof (seq), (caddr_t) &seq); 782 SECASVAR_LOCK(sav); 783 if (ipsec_updatereplay(ntohl(seq), sav)) { 784 SECASVAR_UNLOCK(sav); 785 AHSTAT_INC(ahs_replay); 786 error = EACCES; 787 goto bad; 788 } 789 SECASVAR_UNLOCK(sav); 790 } 791 792 /* 793 * Remove the AH header and authenticator from the mbuf. 794 */ 795 error = m_striphdr(m, skip, ahsize); 796 if (error) { 797 DPRINTF(("%s: mangled mbuf chain for SA %s/%08lx\n", __func__, 798 ipsec_address(&saidx->dst, buf, sizeof(buf)), 799 (u_long) ntohl(sav->spi))); 800 AHSTAT_INC(ahs_hdrops); 801 goto bad; 802 } 803 804 switch (saidx->dst.sa.sa_family) { 805 #ifdef INET6 806 case AF_INET6: 807 error = ipsec6_common_input_cb(m, sav, skip, protoff); 808 break; 809 #endif 810 #ifdef INET 811 case AF_INET: 812 error = ipsec4_common_input_cb(m, sav, skip, protoff); 813 break; 814 #endif 815 default: 816 panic("%s: Unexpected address family: %d saidx=%p", __func__, 817 saidx->dst.sa.sa_family, saidx); 818 } 819 CURVNET_RESTORE(); 820 return error; 821 bad: 822 CURVNET_RESTORE(); 823 if (sav) 824 key_freesav(&sav); 825 if (m != NULL) 826 m_freem(m); 827 if (xd != NULL) 828 free(xd, M_AH); 829 if (crp != NULL) 830 crypto_freereq(crp); 831 return error; 832 } 833 834 /* 835 * AH output routine, called by ipsec[46]_perform_request(). 836 */ 837 static int 838 ah_output(struct mbuf *m, struct secpolicy *sp, struct secasvar *sav, 839 u_int idx, int skip, int protoff) 840 { 841 IPSEC_DEBUG_DECLARE(char buf[IPSEC_ADDRSTRLEN]); 842 const struct auth_hash *ahx; 843 struct xform_data *xd; 844 struct mbuf *mi; 845 struct cryptop *crp; 846 struct newah *ah; 847 crypto_session_t cryptoid; 848 uint16_t iplen; 849 int error, rplen, authsize, ahsize, maxpacketsize, roff; 850 uint8_t prot; 851 uint32_t seqh; 852 853 IPSEC_ASSERT(sav != NULL, ("null SA")); 854 ahx = sav->tdb_authalgxform; 855 IPSEC_ASSERT(ahx != NULL, ("null authentication xform")); 856 857 AHSTAT_INC(ahs_output); 858 859 /* Figure out header size. */ 860 rplen = HDRSIZE(sav); 861 authsize = AUTHSIZE(sav); 862 ahsize = ah_hdrsiz(sav); 863 864 /* Check for maximum packet size violations. */ 865 switch (sav->sah->saidx.dst.sa.sa_family) { 866 #ifdef INET 867 case AF_INET: 868 maxpacketsize = IP_MAXPACKET; 869 break; 870 #endif /* INET */ 871 #ifdef INET6 872 case AF_INET6: 873 maxpacketsize = IPV6_MAXPACKET; 874 break; 875 #endif /* INET6 */ 876 default: 877 DPRINTF(("%s: unknown/unsupported protocol family %u, " 878 "SA %s/%08lx\n", __func__, 879 sav->sah->saidx.dst.sa.sa_family, 880 ipsec_address(&sav->sah->saidx.dst, buf, sizeof(buf)), 881 (u_long) ntohl(sav->spi))); 882 AHSTAT_INC(ahs_nopf); 883 error = EPFNOSUPPORT; 884 goto bad; 885 } 886 if (ahsize + m->m_pkthdr.len > maxpacketsize) { 887 DPRINTF(("%s: packet in SA %s/%08lx got too big " 888 "(len %u, max len %u)\n", __func__, 889 ipsec_address(&sav->sah->saidx.dst, buf, sizeof(buf)), 890 (u_long) ntohl(sav->spi), 891 ahsize + m->m_pkthdr.len, maxpacketsize)); 892 AHSTAT_INC(ahs_toobig); 893 error = EMSGSIZE; 894 goto bad; 895 } 896 897 /* Update the counters. */ 898 AHSTAT_ADD(ahs_obytes, m->m_pkthdr.len - skip); 899 900 m = m_unshare(m, M_NOWAIT); 901 if (m == NULL) { 902 DPRINTF(("%s: cannot clone mbuf chain, SA %s/%08lx\n", __func__, 903 ipsec_address(&sav->sah->saidx.dst, buf, sizeof(buf)), 904 (u_long) ntohl(sav->spi))); 905 AHSTAT_INC(ahs_hdrops); 906 error = ENOBUFS; 907 goto bad; 908 } 909 910 /* Inject AH header. */ 911 mi = m_makespace(m, skip, ahsize, &roff); 912 if (mi == NULL) { 913 DPRINTF(("%s: failed to inject %u byte AH header for SA " 914 "%s/%08lx\n", __func__, ahsize, 915 ipsec_address(&sav->sah->saidx.dst, buf, sizeof(buf)), 916 (u_long) ntohl(sav->spi))); 917 AHSTAT_INC(ahs_hdrops); /*XXX differs from openbsd */ 918 error = ENOBUFS; 919 goto bad; 920 } 921 922 /* 923 * The AH header is guaranteed by m_makespace() to be in 924 * contiguous memory, at roff bytes offset into the returned mbuf. 925 */ 926 ah = (struct newah *)(mtod(mi, caddr_t) + roff); 927 928 /* Initialize the AH header. */ 929 m_copydata(m, protoff, sizeof(u_int8_t), (caddr_t) &ah->ah_nxt); 930 ah->ah_len = (ahsize - sizeof(struct ah)) / sizeof(u_int32_t); 931 ah->ah_reserve = 0; 932 ah->ah_spi = sav->spi; 933 934 /* Zeroize authenticator. */ 935 m_copyback(m, skip + rplen, authsize, ipseczeroes); 936 937 /* Zeroize padding */ 938 m_copyback(m, skip + rplen + authsize, ahsize - (rplen + authsize), 939 ipseczeroes); 940 941 /* Insert packet replay counter, as requested. */ 942 SECASVAR_LOCK(sav); 943 if (sav->replay) { 944 if ((sav->replay->count == ~0 || 945 (!(sav->flags & SADB_X_SAFLAGS_ESN) && 946 ((uint32_t)sav->replay->count) == ~0)) && 947 (sav->flags & SADB_X_EXT_CYCSEQ) == 0) { 948 SECASVAR_UNLOCK(sav); 949 DPRINTF(("%s: replay counter wrapped for SA %s/%08lx\n", 950 __func__, ipsec_address(&sav->sah->saidx.dst, buf, 951 sizeof(buf)), (u_long) ntohl(sav->spi))); 952 AHSTAT_INC(ahs_wrap); 953 error = EACCES; 954 goto bad; 955 } 956 #ifdef REGRESSION 957 /* Emulate replay attack when ipsec_replay is TRUE. */ 958 if (!V_ipsec_replay) 959 #endif 960 sav->replay->count++; 961 ah->ah_seq = htonl((uint32_t)sav->replay->count); 962 } 963 cryptoid = sav->tdb_cryptoid; 964 SECASVAR_UNLOCK(sav); 965 966 /* Get crypto descriptors. */ 967 crp = crypto_getreq(cryptoid, M_NOWAIT); 968 if (crp == NULL) { 969 DPRINTF(("%s: failed to acquire crypto descriptors\n", 970 __func__)); 971 AHSTAT_INC(ahs_crypto); 972 error = ENOBUFS; 973 goto bad; 974 } 975 976 crp->crp_payload_start = 0; 977 crp->crp_payload_length = m->m_pkthdr.len; 978 crp->crp_digest_start = skip + rplen; 979 980 /* Allocate IPsec-specific opaque crypto info. */ 981 xd = malloc(sizeof(struct xform_data) + skip, M_AH, 982 M_NOWAIT | M_ZERO); 983 if (xd == NULL) { 984 crypto_freereq(crp); 985 DPRINTF(("%s: failed to allocate xform_data\n", __func__)); 986 AHSTAT_INC(ahs_crypto); 987 error = ENOBUFS; 988 goto bad; 989 } 990 991 /* Save the skipped portion of the packet. */ 992 m_copydata(m, 0, skip, (caddr_t) (xd + 1)); 993 994 /* 995 * Fix IP header length on the header used for 996 * authentication. We don't need to fix the original 997 * header length as it will be fixed by our caller. 998 */ 999 switch (sav->sah->saidx.dst.sa.sa_family) { 1000 #ifdef INET 1001 case AF_INET: 1002 bcopy(((caddr_t)(xd + 1)) + 1003 offsetof(struct ip, ip_len), 1004 (caddr_t) &iplen, sizeof(u_int16_t)); 1005 iplen = htons(ntohs(iplen) + ahsize); 1006 m_copyback(m, offsetof(struct ip, ip_len), 1007 sizeof(u_int16_t), (caddr_t) &iplen); 1008 break; 1009 #endif /* INET */ 1010 1011 #ifdef INET6 1012 case AF_INET6: 1013 bcopy(((caddr_t)(xd + 1)) + 1014 offsetof(struct ip6_hdr, ip6_plen), 1015 (caddr_t) &iplen, sizeof(uint16_t)); 1016 iplen = htons(ntohs(iplen) + ahsize); 1017 m_copyback(m, offsetof(struct ip6_hdr, ip6_plen), 1018 sizeof(uint16_t), (caddr_t) &iplen); 1019 break; 1020 #endif /* INET6 */ 1021 } 1022 1023 /* Fix the Next Header field in saved header. */ 1024 ((uint8_t *) (xd + 1))[protoff] = IPPROTO_AH; 1025 1026 /* Update the Next Protocol field in the IP header. */ 1027 prot = IPPROTO_AH; 1028 m_copyback(m, protoff, sizeof(uint8_t), (caddr_t) &prot); 1029 1030 /* "Massage" the packet headers for crypto processing. */ 1031 error = ah_massage_headers(&m, sav->sah->saidx.dst.sa.sa_family, 1032 skip, ahx->type, 1); 1033 if (error != 0) { 1034 m = NULL; /* mbuf was free'd by ah_massage_headers. */ 1035 free(xd, M_AH); 1036 crypto_freereq(crp); 1037 goto bad; 1038 } 1039 1040 /* Crypto operation descriptor. */ 1041 crp->crp_op = CRYPTO_OP_COMPUTE_DIGEST; 1042 crp->crp_flags = CRYPTO_F_CBIFSYNC; 1043 crypto_use_mbuf(crp, m); 1044 crp->crp_callback = ah_output_cb; 1045 crp->crp_opaque = xd; 1046 1047 if (sav->flags & SADB_X_SAFLAGS_ESN && sav->replay != NULL) { 1048 seqh = htonl((uint32_t)(sav->replay->count >> IPSEC_SEQH_SHIFT)); 1049 memcpy(crp->crp_esn, &seqh, sizeof(seqh)); 1050 } 1051 1052 /* These are passed as-is to the callback. */ 1053 xd->sp = sp; 1054 xd->sav = sav; 1055 xd->skip = skip; 1056 xd->idx = idx; 1057 xd->cryptoid = cryptoid; 1058 xd->vnet = curvnet; 1059 1060 if (V_async_crypto) 1061 return (crypto_dispatch_async(crp, CRYPTO_ASYNC_ORDERED)); 1062 else 1063 return (crypto_dispatch(crp)); 1064 bad: 1065 if (m) 1066 m_freem(m); 1067 key_freesav(&sav); 1068 key_freesp(&sp); 1069 return (error); 1070 } 1071 1072 /* 1073 * AH output callback from the crypto driver. 1074 */ 1075 static int 1076 ah_output_cb(struct cryptop *crp) 1077 { 1078 struct xform_data *xd; 1079 struct secpolicy *sp; 1080 struct secasvar *sav; 1081 struct mbuf *m; 1082 crypto_session_t cryptoid; 1083 caddr_t ptr; 1084 u_int idx; 1085 int skip, error; 1086 1087 m = crp->crp_buf.cb_mbuf; 1088 xd = (struct xform_data *) crp->crp_opaque; 1089 CURVNET_SET(xd->vnet); 1090 sp = xd->sp; 1091 sav = xd->sav; 1092 skip = xd->skip; 1093 idx = xd->idx; 1094 cryptoid = xd->cryptoid; 1095 ptr = (caddr_t) (xd + 1); 1096 1097 /* Check for crypto errors. */ 1098 if (crp->crp_etype) { 1099 if (crp->crp_etype == EAGAIN) { 1100 /* Reset the session ID */ 1101 if (ipsec_updateid(sav, &crp->crp_session, &cryptoid) != 0) 1102 crypto_freesession(cryptoid); 1103 xd->cryptoid = crp->crp_session; 1104 CURVNET_RESTORE(); 1105 return (crypto_dispatch(crp)); 1106 } 1107 AHSTAT_INC(ahs_noxform); 1108 DPRINTF(("%s: crypto error %d\n", __func__, crp->crp_etype)); 1109 error = crp->crp_etype; 1110 m_freem(m); 1111 goto bad; 1112 } 1113 1114 /* Shouldn't happen... */ 1115 if (m == NULL) { 1116 AHSTAT_INC(ahs_crypto); 1117 DPRINTF(("%s: bogus returned buffer from crypto\n", __func__)); 1118 error = EINVAL; 1119 goto bad; 1120 } 1121 /* 1122 * Copy original headers (with the new protocol number) back 1123 * in place. 1124 */ 1125 m_copyback(m, 0, skip, ptr); 1126 1127 free(xd, M_AH); 1128 crypto_freereq(crp); 1129 AHSTAT_INC(ahs_hist[sav->alg_auth]); 1130 #ifdef REGRESSION 1131 /* Emulate man-in-the-middle attack when ipsec_integrity is TRUE. */ 1132 if (V_ipsec_integrity) { 1133 int alen; 1134 1135 /* 1136 * Corrupt HMAC if we want to test integrity verification of 1137 * the other side. 1138 */ 1139 alen = AUTHSIZE(sav); 1140 m_copyback(m, m->m_pkthdr.len - alen, alen, ipseczeroes); 1141 } 1142 #endif 1143 1144 /* NB: m is reclaimed by ipsec_process_done. */ 1145 error = ipsec_process_done(m, sp, sav, idx); 1146 CURVNET_RESTORE(); 1147 return (error); 1148 bad: 1149 CURVNET_RESTORE(); 1150 free(xd, M_AH); 1151 crypto_freereq(crp); 1152 key_freesav(&sav); 1153 key_freesp(&sp); 1154 return (error); 1155 } 1156 1157 static struct xformsw ah_xformsw = { 1158 .xf_type = XF_AH, 1159 .xf_name = "IPsec AH", 1160 .xf_init = ah_init, 1161 .xf_cleanup = ah_cleanup, 1162 .xf_input = ah_input, 1163 .xf_output = ah_output, 1164 }; 1165 1166 SYSINIT(ah_xform_init, SI_SUB_PROTO_DOMAIN, SI_ORDER_MIDDLE, 1167 xform_attach, &ah_xformsw); 1168 SYSUNINIT(ah_xform_uninit, SI_SUB_PROTO_DOMAIN, SI_ORDER_MIDDLE, 1169 xform_detach, &ah_xformsw); 1170