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/mbuf.h> 46 #include <sys/socket.h> 47 #include <sys/syslog.h> 48 #include <sys/kernel.h> 49 #include <sys/lock.h> 50 #include <sys/mutex.h> 51 #include <sys/sysctl.h> 52 53 #include <net/if.h> 54 #include <net/vnet.h> 55 56 #include <netinet/in.h> 57 #include <netinet/in_systm.h> 58 #include <netinet/ip.h> 59 #include <netinet/ip_ecn.h> 60 #include <netinet/ip6.h> 61 62 #include <netipsec/ipsec.h> 63 #include <netipsec/ah.h> 64 #include <netipsec/ah_var.h> 65 #include <netipsec/xform.h> 66 67 #ifdef INET6 68 #include <netinet6/ip6_var.h> 69 #include <netipsec/ipsec6.h> 70 #include <netinet6/ip6_ecn.h> 71 #endif 72 73 #include <netipsec/key.h> 74 #include <netipsec/key_debug.h> 75 76 #include <opencrypto/cryptodev.h> 77 78 /* 79 * Return header size in bytes. The old protocol did not support 80 * the replay counter; the new protocol always includes the counter. 81 */ 82 #define HDRSIZE(sav) \ 83 (((sav)->flags & SADB_X_EXT_OLD) ? \ 84 sizeof (struct ah) : sizeof (struct ah) + sizeof (u_int32_t)) 85 /* 86 * Return authenticator size in bytes, based on a field in the 87 * algorithm descriptor. 88 */ 89 #define AUTHSIZE(sav) ((sav->flags & SADB_X_EXT_OLD) ? 16 : \ 90 xform_ah_authsize((sav)->tdb_authalgxform)) 91 92 VNET_DEFINE(int, ah_enable) = 1; /* control flow of packets with AH */ 93 VNET_DEFINE(int, ah_cleartos) = 1; /* clear ip_tos when doing AH calc */ 94 VNET_PCPUSTAT_DEFINE(struct ahstat, ahstat); 95 VNET_PCPUSTAT_SYSINIT(ahstat); 96 97 #ifdef VIMAGE 98 VNET_PCPUSTAT_SYSUNINIT(ahstat); 99 #endif /* VIMAGE */ 100 101 #ifdef INET 102 SYSCTL_DECL(_net_inet_ah); 103 SYSCTL_INT(_net_inet_ah, OID_AUTO, ah_enable, 104 CTLFLAG_VNET | CTLFLAG_RW, &VNET_NAME(ah_enable), 0, ""); 105 SYSCTL_INT(_net_inet_ah, OID_AUTO, ah_cleartos, 106 CTLFLAG_VNET | CTLFLAG_RW, &VNET_NAME(ah_cleartos), 0, ""); 107 SYSCTL_VNET_PCPUSTAT(_net_inet_ah, IPSECCTL_STATS, stats, struct ahstat, 108 ahstat, "AH statistics (struct ahstat, netipsec/ah_var.h)"); 109 #endif 110 111 static unsigned char ipseczeroes[256]; /* larger than an ip6 extension hdr */ 112 113 static int ah_input_cb(struct cryptop*); 114 static int ah_output_cb(struct cryptop*); 115 116 int 117 xform_ah_authsize(const struct auth_hash *esph) 118 { 119 int alen; 120 121 if (esph == NULL) 122 return 0; 123 124 switch (esph->type) { 125 case CRYPTO_SHA2_256_HMAC: 126 case CRYPTO_SHA2_384_HMAC: 127 case CRYPTO_SHA2_512_HMAC: 128 alen = esph->hashsize / 2; /* RFC4868 2.3 */ 129 break; 130 131 case CRYPTO_AES_NIST_GMAC: 132 alen = esph->hashsize; 133 break; 134 135 default: 136 alen = AH_HMAC_HASHLEN; 137 break; 138 } 139 140 return alen; 141 } 142 143 size_t 144 ah_hdrsiz(struct secasvar *sav) 145 { 146 size_t size; 147 148 if (sav != NULL) { 149 int authsize, rplen, align; 150 151 IPSEC_ASSERT(sav->tdb_authalgxform != NULL, ("null xform")); 152 /*XXX not right for null algorithm--does it matter??*/ 153 154 /* RFC4302: use the correct alignment. */ 155 align = sizeof(uint32_t); 156 #ifdef INET6 157 if (sav->sah->saidx.dst.sa.sa_family == AF_INET6) { 158 align = sizeof(uint64_t); 159 } 160 #endif 161 rplen = HDRSIZE(sav); 162 authsize = AUTHSIZE(sav); 163 size = roundup(rplen + authsize, align); 164 } else { 165 /* default guess */ 166 size = sizeof (struct ah) + sizeof (u_int32_t) + 16; 167 } 168 return size; 169 } 170 171 /* 172 * NB: public for use by esp_init. 173 */ 174 int 175 ah_init0(struct secasvar *sav, struct xformsw *xsp, 176 struct crypto_session_params *csp) 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 /* 189 * Verify the replay state block allocation is consistent with 190 * the protocol type. We check here so we can make assumptions 191 * later during protocol processing. 192 */ 193 /* NB: replay state is setup elsewhere (sigh) */ 194 if (((sav->flags&SADB_X_EXT_OLD) == 0) ^ (sav->replay != NULL)) { 195 DPRINTF(("%s: replay state block inconsistency, " 196 "%s algorithm %s replay state\n", __func__, 197 (sav->flags & SADB_X_EXT_OLD) ? "old" : "new", 198 sav->replay == NULL ? "without" : "with")); 199 return EINVAL; 200 } 201 if (sav->key_auth == NULL) { 202 DPRINTF(("%s: no authentication key for %s algorithm\n", 203 __func__, thash->name)); 204 return EINVAL; 205 } 206 keylen = _KEYLEN(sav->key_auth); 207 if (keylen > thash->keysize && thash->keysize != 0) { 208 DPRINTF(("%s: invalid keylength %d, algorithm %s requires " 209 "keysize less than %d\n", __func__, 210 keylen, thash->name, thash->keysize)); 211 return EINVAL; 212 } 213 214 sav->tdb_xform = xsp; 215 sav->tdb_authalgxform = thash; 216 217 /* Initialize crypto session. */ 218 csp->csp_auth_alg = sav->tdb_authalgxform->type; 219 if (csp->csp_auth_alg != CRYPTO_NULL_HMAC) { 220 csp->csp_auth_klen = _KEYBITS(sav->key_auth) / 8; 221 csp->csp_auth_key = sav->key_auth->key_data; 222 }; 223 csp->csp_auth_mlen = AUTHSIZE(sav); 224 225 return 0; 226 } 227 228 /* 229 * ah_init() is called when an SPI is being set up. 230 */ 231 static int 232 ah_init(struct secasvar *sav, struct xformsw *xsp) 233 { 234 struct crypto_session_params csp; 235 int error; 236 237 memset(&csp, 0, sizeof(csp)); 238 csp.csp_mode = CSP_MODE_DIGEST; 239 240 if (sav->flags & SADB_X_SAFLAGS_ESN) 241 csp.csp_flags |= CSP_F_ESN; 242 243 error = ah_init0(sav, xsp, &csp); 244 return error ? error : 245 crypto_newsession(&sav->tdb_cryptoid, &csp, V_crypto_support); 246 } 247 248 static void 249 ah_cleanup(struct secasvar *sav) 250 { 251 252 crypto_freesession(sav->tdb_cryptoid); 253 sav->tdb_cryptoid = NULL; 254 sav->tdb_authalgxform = NULL; 255 } 256 257 /* 258 * Massage IPv4/IPv6 headers for AH processing. 259 */ 260 static int 261 ah_massage_headers(struct mbuf **m0, int proto, int skip, int alg, int out) 262 { 263 struct mbuf *m = *m0; 264 unsigned char *ptr; 265 int off, count; 266 267 #ifdef INET 268 struct ip *ip; 269 #endif /* INET */ 270 271 #ifdef INET6 272 struct ip6_ext *ip6e; 273 struct ip6_hdr ip6; 274 int ad, alloc, nxt, noff; 275 #endif /* INET6 */ 276 277 switch (proto) { 278 #ifdef INET 279 case AF_INET: 280 /* 281 * This is the least painful way of dealing with IPv4 header 282 * and option processing -- just make sure they're in 283 * contiguous memory. 284 */ 285 *m0 = m = m_pullup(m, skip); 286 if (m == NULL) { 287 DPRINTF(("%s: m_pullup failed\n", __func__)); 288 return ENOBUFS; 289 } 290 291 /* Fix the IP header */ 292 ip = mtod(m, struct ip *); 293 if (V_ah_cleartos) 294 ip->ip_tos = 0; 295 ip->ip_ttl = 0; 296 ip->ip_sum = 0; 297 ip->ip_off = htons(0); 298 299 ptr = mtod(m, unsigned char *); 300 301 /* IPv4 option processing */ 302 for (off = sizeof(struct ip); off < skip;) { 303 if (ptr[off] == IPOPT_EOL || ptr[off] == IPOPT_NOP || 304 off + 1 < skip) 305 ; 306 else { 307 DPRINTF(("%s: illegal IPv4 option length for " 308 "option %d\n", __func__, ptr[off])); 309 310 m_freem(m); 311 return EINVAL; 312 } 313 314 switch (ptr[off]) { 315 case IPOPT_EOL: 316 off = skip; /* End the loop. */ 317 break; 318 319 case IPOPT_NOP: 320 off++; 321 break; 322 323 case IPOPT_SECURITY: /* 0x82 */ 324 case 0x85: /* Extended security. */ 325 case 0x86: /* Commercial security. */ 326 case 0x94: /* Router alert */ 327 case 0x95: /* RFC1770 */ 328 /* Sanity check for option length. */ 329 if (ptr[off + 1] < 2) { 330 DPRINTF(("%s: illegal IPv4 option " 331 "length for option %d\n", 332 __func__, ptr[off])); 333 334 m_freem(m); 335 return EINVAL; 336 } 337 338 off += ptr[off + 1]; 339 break; 340 341 case IPOPT_LSRR: 342 case IPOPT_SSRR: 343 /* Sanity check for option length. */ 344 if (ptr[off + 1] < 2) { 345 DPRINTF(("%s: illegal IPv4 option " 346 "length for option %d\n", 347 __func__, ptr[off])); 348 349 m_freem(m); 350 return EINVAL; 351 } 352 353 /* 354 * On output, if we have either of the 355 * source routing options, we should 356 * swap the destination address of the 357 * IP header with the last address 358 * specified in the option, as that is 359 * what the destination's IP header 360 * will look like. 361 */ 362 if (out) 363 bcopy(ptr + off + ptr[off + 1] - 364 sizeof(struct in_addr), 365 &(ip->ip_dst), sizeof(struct in_addr)); 366 367 /* Fall through */ 368 default: 369 /* Sanity check for option length. */ 370 if (ptr[off + 1] < 2) { 371 DPRINTF(("%s: illegal IPv4 option " 372 "length for option %d\n", 373 __func__, ptr[off])); 374 m_freem(m); 375 return EINVAL; 376 } 377 378 /* Zeroize all other options. */ 379 count = ptr[off + 1]; 380 bcopy(ipseczeroes, ptr + off, count); 381 off += count; 382 break; 383 } 384 385 /* Sanity check. */ 386 if (off > skip) { 387 DPRINTF(("%s: malformed IPv4 options header\n", 388 __func__)); 389 390 m_freem(m); 391 return EINVAL; 392 } 393 } 394 395 break; 396 #endif /* INET */ 397 398 #ifdef INET6 399 case AF_INET6: /* Ugly... */ 400 /* Copy and "cook" the IPv6 header. */ 401 m_copydata(m, 0, sizeof(ip6), (caddr_t) &ip6); 402 403 /* We don't do IPv6 Jumbograms. */ 404 if (ip6.ip6_plen == 0) { 405 DPRINTF(("%s: unsupported IPv6 jumbogram\n", __func__)); 406 m_freem(m); 407 return EMSGSIZE; 408 } 409 410 ip6.ip6_flow = 0; 411 ip6.ip6_hlim = 0; 412 ip6.ip6_vfc &= ~IPV6_VERSION_MASK; 413 ip6.ip6_vfc |= IPV6_VERSION; 414 415 /* Scoped address handling. */ 416 if (IN6_IS_SCOPE_LINKLOCAL(&ip6.ip6_src)) 417 ip6.ip6_src.s6_addr16[1] = 0; 418 if (IN6_IS_SCOPE_LINKLOCAL(&ip6.ip6_dst)) 419 ip6.ip6_dst.s6_addr16[1] = 0; 420 421 /* Done with IPv6 header. */ 422 m_copyback(m, 0, sizeof(struct ip6_hdr), (caddr_t) &ip6); 423 424 /* Let's deal with the remaining headers (if any). */ 425 if (skip - sizeof(struct ip6_hdr) > 0) { 426 if (m->m_len <= skip) { 427 ptr = (unsigned char *) malloc( 428 skip - sizeof(struct ip6_hdr), 429 M_XDATA, M_NOWAIT); 430 if (ptr == NULL) { 431 DPRINTF(("%s: failed to allocate memory" 432 "for IPv6 headers\n",__func__)); 433 m_freem(m); 434 return ENOBUFS; 435 } 436 437 /* 438 * Copy all the protocol headers after 439 * the IPv6 header. 440 */ 441 m_copydata(m, sizeof(struct ip6_hdr), 442 skip - sizeof(struct ip6_hdr), ptr); 443 alloc = 1; 444 } else { 445 /* No need to allocate memory. */ 446 ptr = mtod(m, unsigned char *) + 447 sizeof(struct ip6_hdr); 448 alloc = 0; 449 } 450 } else 451 break; 452 453 nxt = ip6.ip6_nxt & 0xff; /* Next header type. */ 454 455 for (off = 0; off < skip - sizeof(struct ip6_hdr);) 456 switch (nxt) { 457 case IPPROTO_HOPOPTS: 458 case IPPROTO_DSTOPTS: 459 ip6e = (struct ip6_ext *)(ptr + off); 460 noff = off + ((ip6e->ip6e_len + 1) << 3); 461 462 /* Sanity check. */ 463 if (noff > skip - sizeof(struct ip6_hdr)) 464 goto error6; 465 466 /* 467 * Zero out mutable options. 468 */ 469 for (count = off + sizeof(struct ip6_ext); 470 count < noff;) { 471 if (ptr[count] == IP6OPT_PAD1) { 472 count++; 473 continue; /* Skip padding. */ 474 } 475 476 ad = ptr[count + 1] + 2; 477 if (count + ad > noff) 478 goto error6; 479 480 if (ptr[count] & IP6OPT_MUTABLE) 481 memset(ptr + count, 0, ad); 482 count += ad; 483 } 484 485 if (count != noff) 486 goto error6; 487 488 /* Advance. */ 489 off += ((ip6e->ip6e_len + 1) << 3); 490 nxt = ip6e->ip6e_nxt; 491 break; 492 493 case IPPROTO_ROUTING: 494 /* 495 * Always include routing headers in 496 * computation. 497 */ 498 ip6e = (struct ip6_ext *) (ptr + off); 499 off += ((ip6e->ip6e_len + 1) << 3); 500 nxt = ip6e->ip6e_nxt; 501 break; 502 503 default: 504 DPRINTF(("%s: unexpected IPv6 header type %d", 505 __func__, off)); 506 error6: 507 if (alloc) 508 free(ptr, M_XDATA); 509 m_freem(m); 510 return EINVAL; 511 } 512 513 /* Copyback and free, if we allocated. */ 514 if (alloc) { 515 m_copyback(m, sizeof(struct ip6_hdr), 516 skip - sizeof(struct ip6_hdr), ptr); 517 free(ptr, M_XDATA); 518 } 519 520 break; 521 #endif /* INET6 */ 522 } 523 524 return 0; 525 } 526 527 /* 528 * ah_input() gets called to verify that an input packet 529 * passes authentication. 530 */ 531 static int 532 ah_input(struct mbuf *m, struct secasvar *sav, int skip, int protoff) 533 { 534 IPSEC_DEBUG_DECLARE(char buf[128]); 535 const struct auth_hash *ahx; 536 struct cryptop *crp; 537 struct xform_data *xd; 538 struct newah *ah; 539 crypto_session_t cryptoid; 540 int hl, rplen, authsize, ahsize, error; 541 uint32_t seqh; 542 543 IPSEC_ASSERT(sav != NULL, ("null SA")); 544 IPSEC_ASSERT(sav->key_auth != NULL, ("null authentication key")); 545 IPSEC_ASSERT(sav->tdb_authalgxform != NULL, 546 ("null authentication xform")); 547 548 /* Figure out header size. */ 549 rplen = HDRSIZE(sav); 550 551 if (m->m_len < skip + rplen) { 552 m = m_pullup(m, skip + rplen); 553 if (m == NULL) { 554 DPRINTF(("ah_input: cannot pullup header\n")); 555 AHSTAT_INC(ahs_hdrops); /*XXX*/ 556 error = ENOBUFS; 557 goto bad; 558 } 559 } 560 ah = (struct newah *)(mtod(m, caddr_t) + skip); 561 562 /* Check replay window, if applicable. */ 563 SECASVAR_LOCK(sav); 564 if (sav->replay != NULL && sav->replay->wsize != 0 && 565 ipsec_chkreplay(ntohl(ah->ah_seq), &seqh, sav) == 0) { 566 SECASVAR_UNLOCK(sav); 567 AHSTAT_INC(ahs_replay); 568 DPRINTF(("%s: packet replay failure: %s\n", __func__, 569 ipsec_sa2str(sav, buf, sizeof(buf)))); 570 error = EACCES; 571 goto bad; 572 } 573 cryptoid = sav->tdb_cryptoid; 574 SECASVAR_UNLOCK(sav); 575 576 /* Verify AH header length. */ 577 hl = sizeof(struct ah) + (ah->ah_len * sizeof (u_int32_t)); 578 ahx = sav->tdb_authalgxform; 579 authsize = AUTHSIZE(sav); 580 ahsize = ah_hdrsiz(sav); 581 if (hl != ahsize) { 582 DPRINTF(("%s: bad authenticator length %u (expecting %lu)" 583 " for packet in SA %s/%08lx\n", __func__, hl, 584 (u_long)ahsize, 585 ipsec_address(&sav->sah->saidx.dst, buf, sizeof(buf)), 586 (u_long) ntohl(sav->spi))); 587 AHSTAT_INC(ahs_badauthl); 588 error = EACCES; 589 goto bad; 590 } 591 if (skip + ahsize > m->m_pkthdr.len) { 592 DPRINTF(("%s: bad mbuf length %u (expecting %lu)" 593 " for packet in SA %s/%08lx\n", __func__, 594 m->m_pkthdr.len, (u_long)(skip + ahsize), 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(cryptoid, M_NOWAIT); 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 crp->crp_payload_start = 0; 614 crp->crp_payload_length = m->m_pkthdr.len; 615 crp->crp_digest_start = skip + rplen; 616 617 /* Allocate IPsec-specific opaque crypto info. */ 618 xd = malloc(sizeof(*xd) + skip + rplen + authsize, M_XDATA, 619 M_NOWAIT | M_ZERO); 620 if (xd == NULL) { 621 DPRINTF(("%s: failed to allocate xform_data\n", __func__)); 622 AHSTAT_INC(ahs_crypto); 623 crypto_freereq(crp); 624 error = ENOBUFS; 625 goto bad; 626 } 627 628 /* 629 * Save the authenticator, the skipped portion of the packet, 630 * and the AH header. 631 */ 632 m_copydata(m, 0, skip + rplen + authsize, (caddr_t)(xd + 1)); 633 634 /* Zeroize the authenticator on the packet. */ 635 m_copyback(m, skip + rplen, authsize, ipseczeroes); 636 637 /* Save ah_nxt, since ah pointer can become invalid after "massage" */ 638 hl = ah->ah_nxt; 639 640 /* "Massage" the packet headers for crypto processing. */ 641 error = ah_massage_headers(&m, sav->sah->saidx.dst.sa.sa_family, 642 skip, ahx->type, 0); 643 if (error != 0) { 644 /* NB: mbuf is free'd by ah_massage_headers */ 645 AHSTAT_INC(ahs_hdrops); 646 free(xd, M_XDATA); 647 crypto_freereq(crp); 648 key_freesav(&sav); 649 return (error); 650 } 651 652 /* Crypto operation descriptor. */ 653 crp->crp_op = CRYPTO_OP_COMPUTE_DIGEST; 654 crp->crp_flags = CRYPTO_F_CBIFSYNC; 655 if (V_async_crypto) 656 crp->crp_flags |= CRYPTO_F_ASYNC | CRYPTO_F_ASYNC_KEEPORDER; 657 crypto_use_mbuf(crp, m); 658 crp->crp_callback = ah_input_cb; 659 crp->crp_opaque = xd; 660 661 if (sav->flags & SADB_X_SAFLAGS_ESN && 662 sav->replay != NULL && sav->replay->wsize != 0) { 663 seqh = htonl(seqh); 664 memcpy(crp->crp_esn, &seqh, sizeof(seqh)); 665 } 666 667 /* These are passed as-is to the callback. */ 668 xd->sav = sav; 669 xd->nxt = hl; 670 xd->protoff = protoff; 671 xd->skip = skip; 672 xd->cryptoid = cryptoid; 673 xd->vnet = curvnet; 674 return (crypto_dispatch(crp)); 675 bad: 676 m_freem(m); 677 key_freesav(&sav); 678 return (error); 679 } 680 681 /* 682 * AH input callback from the crypto driver. 683 */ 684 static int 685 ah_input_cb(struct cryptop *crp) 686 { 687 IPSEC_DEBUG_DECLARE(char buf[IPSEC_ADDRSTRLEN]); 688 unsigned char calc[AH_ALEN_MAX]; 689 struct mbuf *m; 690 struct xform_data *xd; 691 struct secasvar *sav; 692 struct secasindex *saidx; 693 caddr_t ptr; 694 crypto_session_t cryptoid; 695 int authsize, rplen, ahsize, error, skip, protoff; 696 uint8_t nxt; 697 698 m = crp->crp_buf.cb_mbuf; 699 xd = crp->crp_opaque; 700 CURVNET_SET(xd->vnet); 701 sav = xd->sav; 702 skip = xd->skip; 703 nxt = xd->nxt; 704 protoff = xd->protoff; 705 cryptoid = xd->cryptoid; 706 saidx = &sav->sah->saidx; 707 IPSEC_ASSERT(saidx->dst.sa.sa_family == AF_INET || 708 saidx->dst.sa.sa_family == AF_INET6, 709 ("unexpected protocol family %u", saidx->dst.sa.sa_family)); 710 711 /* Check for crypto errors. */ 712 if (crp->crp_etype) { 713 if (crp->crp_etype == EAGAIN) { 714 /* Reset the session ID */ 715 if (ipsec_updateid(sav, &crp->crp_session, &cryptoid) != 0) 716 crypto_freesession(cryptoid); 717 xd->cryptoid = crp->crp_session; 718 CURVNET_RESTORE(); 719 return (crypto_dispatch(crp)); 720 } 721 AHSTAT_INC(ahs_noxform); 722 DPRINTF(("%s: crypto error %d\n", __func__, crp->crp_etype)); 723 error = crp->crp_etype; 724 goto bad; 725 } else { 726 AHSTAT_INC(ahs_hist[sav->alg_auth]); 727 crypto_freereq(crp); /* No longer needed. */ 728 crp = NULL; 729 } 730 731 /* Shouldn't happen... */ 732 if (m == NULL) { 733 AHSTAT_INC(ahs_crypto); 734 DPRINTF(("%s: bogus returned buffer from crypto\n", __func__)); 735 error = EINVAL; 736 goto bad; 737 } 738 739 /* Figure out header size. */ 740 rplen = HDRSIZE(sav); 741 authsize = AUTHSIZE(sav); 742 ahsize = ah_hdrsiz(sav); 743 744 /* Copy authenticator off the packet. */ 745 m_copydata(m, skip + rplen, authsize, calc); 746 747 /* Verify authenticator. */ 748 ptr = (caddr_t) (xd + 1); 749 if (timingsafe_bcmp(ptr + skip + rplen, calc, authsize)) { 750 DPRINTF(("%s: authentication hash mismatch for packet " 751 "in SA %s/%08lx\n", __func__, 752 ipsec_address(&saidx->dst, buf, sizeof(buf)), 753 (u_long) ntohl(sav->spi))); 754 AHSTAT_INC(ahs_badauth); 755 error = EACCES; 756 goto bad; 757 } 758 /* Fix the Next Protocol field. */ 759 ((uint8_t *) ptr)[protoff] = nxt; 760 761 /* Copyback the saved (uncooked) network headers. */ 762 m_copyback(m, 0, skip, ptr); 763 free(xd, M_XDATA), xd = NULL; /* No longer needed */ 764 765 /* 766 * Header is now authenticated. 767 */ 768 m->m_flags |= M_AUTHIPHDR|M_AUTHIPDGM; 769 770 /* 771 * Update replay sequence number, if appropriate. 772 */ 773 if (sav->replay) { 774 u_int32_t seq; 775 776 m_copydata(m, skip + offsetof(struct newah, ah_seq), 777 sizeof (seq), (caddr_t) &seq); 778 SECASVAR_LOCK(sav); 779 if (ipsec_updatereplay(ntohl(seq), sav)) { 780 SECASVAR_UNLOCK(sav); 781 AHSTAT_INC(ahs_replay); 782 error = EACCES; 783 goto bad; 784 } 785 SECASVAR_UNLOCK(sav); 786 } 787 788 /* 789 * Remove the AH header and authenticator from the mbuf. 790 */ 791 error = m_striphdr(m, skip, ahsize); 792 if (error) { 793 DPRINTF(("%s: mangled mbuf chain for SA %s/%08lx\n", __func__, 794 ipsec_address(&saidx->dst, buf, sizeof(buf)), 795 (u_long) ntohl(sav->spi))); 796 AHSTAT_INC(ahs_hdrops); 797 goto bad; 798 } 799 800 switch (saidx->dst.sa.sa_family) { 801 #ifdef INET6 802 case AF_INET6: 803 error = ipsec6_common_input_cb(m, sav, skip, protoff); 804 break; 805 #endif 806 #ifdef INET 807 case AF_INET: 808 error = ipsec4_common_input_cb(m, sav, skip, protoff); 809 break; 810 #endif 811 default: 812 panic("%s: Unexpected address family: %d saidx=%p", __func__, 813 saidx->dst.sa.sa_family, saidx); 814 } 815 CURVNET_RESTORE(); 816 return error; 817 bad: 818 CURVNET_RESTORE(); 819 if (sav) 820 key_freesav(&sav); 821 if (m != NULL) 822 m_freem(m); 823 if (xd != NULL) 824 free(xd, M_XDATA); 825 if (crp != NULL) 826 crypto_freereq(crp); 827 return error; 828 } 829 830 /* 831 * AH output routine, called by ipsec[46]_perform_request(). 832 */ 833 static int 834 ah_output(struct mbuf *m, struct secpolicy *sp, struct secasvar *sav, 835 u_int idx, int skip, int protoff) 836 { 837 IPSEC_DEBUG_DECLARE(char buf[IPSEC_ADDRSTRLEN]); 838 const struct auth_hash *ahx; 839 struct xform_data *xd; 840 struct mbuf *mi; 841 struct cryptop *crp; 842 struct newah *ah; 843 crypto_session_t cryptoid; 844 uint16_t iplen; 845 int error, rplen, authsize, ahsize, maxpacketsize, roff; 846 uint8_t prot; 847 uint32_t seqh; 848 849 IPSEC_ASSERT(sav != NULL, ("null SA")); 850 ahx = sav->tdb_authalgxform; 851 IPSEC_ASSERT(ahx != NULL, ("null authentication xform")); 852 853 AHSTAT_INC(ahs_output); 854 855 /* Figure out header size. */ 856 rplen = HDRSIZE(sav); 857 authsize = AUTHSIZE(sav); 858 ahsize = ah_hdrsiz(sav); 859 860 /* Check for maximum packet size violations. */ 861 switch (sav->sah->saidx.dst.sa.sa_family) { 862 #ifdef INET 863 case AF_INET: 864 maxpacketsize = IP_MAXPACKET; 865 break; 866 #endif /* INET */ 867 #ifdef INET6 868 case AF_INET6: 869 maxpacketsize = IPV6_MAXPACKET; 870 break; 871 #endif /* INET6 */ 872 default: 873 DPRINTF(("%s: unknown/unsupported protocol family %u, " 874 "SA %s/%08lx\n", __func__, 875 sav->sah->saidx.dst.sa.sa_family, 876 ipsec_address(&sav->sah->saidx.dst, buf, sizeof(buf)), 877 (u_long) ntohl(sav->spi))); 878 AHSTAT_INC(ahs_nopf); 879 error = EPFNOSUPPORT; 880 goto bad; 881 } 882 if (ahsize + m->m_pkthdr.len > maxpacketsize) { 883 DPRINTF(("%s: packet in SA %s/%08lx got too big " 884 "(len %u, max len %u)\n", __func__, 885 ipsec_address(&sav->sah->saidx.dst, buf, sizeof(buf)), 886 (u_long) ntohl(sav->spi), 887 ahsize + m->m_pkthdr.len, maxpacketsize)); 888 AHSTAT_INC(ahs_toobig); 889 error = EMSGSIZE; 890 goto bad; 891 } 892 893 /* Update the counters. */ 894 AHSTAT_ADD(ahs_obytes, m->m_pkthdr.len - skip); 895 896 m = m_unshare(m, M_NOWAIT); 897 if (m == NULL) { 898 DPRINTF(("%s: cannot clone mbuf chain, SA %s/%08lx\n", __func__, 899 ipsec_address(&sav->sah->saidx.dst, buf, sizeof(buf)), 900 (u_long) ntohl(sav->spi))); 901 AHSTAT_INC(ahs_hdrops); 902 error = ENOBUFS; 903 goto bad; 904 } 905 906 /* Inject AH header. */ 907 mi = m_makespace(m, skip, ahsize, &roff); 908 if (mi == NULL) { 909 DPRINTF(("%s: failed to inject %u byte AH header for SA " 910 "%s/%08lx\n", __func__, ahsize, 911 ipsec_address(&sav->sah->saidx.dst, buf, sizeof(buf)), 912 (u_long) ntohl(sav->spi))); 913 AHSTAT_INC(ahs_hdrops); /*XXX differs from openbsd */ 914 error = ENOBUFS; 915 goto bad; 916 } 917 918 /* 919 * The AH header is guaranteed by m_makespace() to be in 920 * contiguous memory, at roff bytes offset into the returned mbuf. 921 */ 922 ah = (struct newah *)(mtod(mi, caddr_t) + roff); 923 924 /* Initialize the AH header. */ 925 m_copydata(m, protoff, sizeof(u_int8_t), (caddr_t) &ah->ah_nxt); 926 ah->ah_len = (ahsize - sizeof(struct ah)) / sizeof(u_int32_t); 927 ah->ah_reserve = 0; 928 ah->ah_spi = sav->spi; 929 930 /* Zeroize authenticator. */ 931 m_copyback(m, skip + rplen, authsize, ipseczeroes); 932 933 /* Zeroize padding */ 934 m_copyback(m, skip + rplen + authsize, ahsize - (rplen + authsize), 935 ipseczeroes); 936 937 /* Insert packet replay counter, as requested. */ 938 SECASVAR_LOCK(sav); 939 if (sav->replay) { 940 if ((sav->replay->count == ~0 || 941 (!(sav->flags & SADB_X_SAFLAGS_ESN) && 942 ((uint32_t)sav->replay->count) == ~0)) && 943 (sav->flags & SADB_X_EXT_CYCSEQ) == 0) { 944 SECASVAR_UNLOCK(sav); 945 DPRINTF(("%s: replay counter wrapped for SA %s/%08lx\n", 946 __func__, ipsec_address(&sav->sah->saidx.dst, buf, 947 sizeof(buf)), (u_long) ntohl(sav->spi))); 948 AHSTAT_INC(ahs_wrap); 949 error = EACCES; 950 goto bad; 951 } 952 #ifdef REGRESSION 953 /* Emulate replay attack when ipsec_replay is TRUE. */ 954 if (!V_ipsec_replay) 955 #endif 956 sav->replay->count++; 957 ah->ah_seq = htonl((uint32_t)sav->replay->count); 958 } 959 cryptoid = sav->tdb_cryptoid; 960 SECASVAR_UNLOCK(sav); 961 962 /* Get crypto descriptors. */ 963 crp = crypto_getreq(cryptoid, M_NOWAIT); 964 if (crp == NULL) { 965 DPRINTF(("%s: failed to acquire crypto descriptors\n", 966 __func__)); 967 AHSTAT_INC(ahs_crypto); 968 error = ENOBUFS; 969 goto bad; 970 } 971 972 crp->crp_payload_start = 0; 973 crp->crp_payload_length = m->m_pkthdr.len; 974 crp->crp_digest_start = skip + rplen; 975 976 /* Allocate IPsec-specific opaque crypto info. */ 977 xd = malloc(sizeof(struct xform_data) + skip, M_XDATA, 978 M_NOWAIT | M_ZERO); 979 if (xd == NULL) { 980 crypto_freereq(crp); 981 DPRINTF(("%s: failed to allocate xform_data\n", __func__)); 982 AHSTAT_INC(ahs_crypto); 983 error = ENOBUFS; 984 goto bad; 985 } 986 987 /* Save the skipped portion of the packet. */ 988 m_copydata(m, 0, skip, (caddr_t) (xd + 1)); 989 990 /* 991 * Fix IP header length on the header used for 992 * authentication. We don't need to fix the original 993 * header length as it will be fixed by our caller. 994 */ 995 switch (sav->sah->saidx.dst.sa.sa_family) { 996 #ifdef INET 997 case AF_INET: 998 bcopy(((caddr_t)(xd + 1)) + 999 offsetof(struct ip, ip_len), 1000 (caddr_t) &iplen, sizeof(u_int16_t)); 1001 iplen = htons(ntohs(iplen) + ahsize); 1002 m_copyback(m, offsetof(struct ip, ip_len), 1003 sizeof(u_int16_t), (caddr_t) &iplen); 1004 break; 1005 #endif /* INET */ 1006 1007 #ifdef INET6 1008 case AF_INET6: 1009 bcopy(((caddr_t)(xd + 1)) + 1010 offsetof(struct ip6_hdr, ip6_plen), 1011 (caddr_t) &iplen, sizeof(uint16_t)); 1012 iplen = htons(ntohs(iplen) + ahsize); 1013 m_copyback(m, offsetof(struct ip6_hdr, ip6_plen), 1014 sizeof(uint16_t), (caddr_t) &iplen); 1015 break; 1016 #endif /* INET6 */ 1017 } 1018 1019 /* Fix the Next Header field in saved header. */ 1020 ((uint8_t *) (xd + 1))[protoff] = IPPROTO_AH; 1021 1022 /* Update the Next Protocol field in the IP header. */ 1023 prot = IPPROTO_AH; 1024 m_copyback(m, protoff, sizeof(uint8_t), (caddr_t) &prot); 1025 1026 /* "Massage" the packet headers for crypto processing. */ 1027 error = ah_massage_headers(&m, sav->sah->saidx.dst.sa.sa_family, 1028 skip, ahx->type, 1); 1029 if (error != 0) { 1030 m = NULL; /* mbuf was free'd by ah_massage_headers. */ 1031 free(xd, M_XDATA); 1032 crypto_freereq(crp); 1033 goto bad; 1034 } 1035 1036 /* Crypto operation descriptor. */ 1037 crp->crp_op = CRYPTO_OP_COMPUTE_DIGEST; 1038 crp->crp_flags = CRYPTO_F_CBIFSYNC; 1039 if (V_async_crypto) 1040 crp->crp_flags |= CRYPTO_F_ASYNC | CRYPTO_F_ASYNC_KEEPORDER; 1041 crypto_use_mbuf(crp, m); 1042 crp->crp_callback = ah_output_cb; 1043 crp->crp_opaque = xd; 1044 1045 if (sav->flags & SADB_X_SAFLAGS_ESN && sav->replay != NULL) { 1046 seqh = htonl((uint32_t)(sav->replay->count >> IPSEC_SEQH_SHIFT)); 1047 memcpy(crp->crp_esn, &seqh, sizeof(seqh)); 1048 } 1049 1050 /* These are passed as-is to the callback. */ 1051 xd->sp = sp; 1052 xd->sav = sav; 1053 xd->skip = skip; 1054 xd->idx = idx; 1055 xd->cryptoid = cryptoid; 1056 xd->vnet = curvnet; 1057 1058 return crypto_dispatch(crp); 1059 bad: 1060 if (m) 1061 m_freem(m); 1062 key_freesav(&sav); 1063 key_freesp(&sp); 1064 return (error); 1065 } 1066 1067 /* 1068 * AH output callback from the crypto driver. 1069 */ 1070 static int 1071 ah_output_cb(struct cryptop *crp) 1072 { 1073 struct xform_data *xd; 1074 struct secpolicy *sp; 1075 struct secasvar *sav; 1076 struct mbuf *m; 1077 crypto_session_t cryptoid; 1078 caddr_t ptr; 1079 u_int idx; 1080 int skip, error; 1081 1082 m = crp->crp_buf.cb_mbuf; 1083 xd = (struct xform_data *) crp->crp_opaque; 1084 CURVNET_SET(xd->vnet); 1085 sp = xd->sp; 1086 sav = xd->sav; 1087 skip = xd->skip; 1088 idx = xd->idx; 1089 cryptoid = xd->cryptoid; 1090 ptr = (caddr_t) (xd + 1); 1091 1092 /* Check for crypto errors. */ 1093 if (crp->crp_etype) { 1094 if (crp->crp_etype == EAGAIN) { 1095 /* Reset the session ID */ 1096 if (ipsec_updateid(sav, &crp->crp_session, &cryptoid) != 0) 1097 crypto_freesession(cryptoid); 1098 xd->cryptoid = crp->crp_session; 1099 CURVNET_RESTORE(); 1100 return (crypto_dispatch(crp)); 1101 } 1102 AHSTAT_INC(ahs_noxform); 1103 DPRINTF(("%s: crypto error %d\n", __func__, crp->crp_etype)); 1104 error = crp->crp_etype; 1105 m_freem(m); 1106 goto bad; 1107 } 1108 1109 /* Shouldn't happen... */ 1110 if (m == NULL) { 1111 AHSTAT_INC(ahs_crypto); 1112 DPRINTF(("%s: bogus returned buffer from crypto\n", __func__)); 1113 error = EINVAL; 1114 goto bad; 1115 } 1116 /* 1117 * Copy original headers (with the new protocol number) back 1118 * in place. 1119 */ 1120 m_copyback(m, 0, skip, ptr); 1121 1122 free(xd, M_XDATA); 1123 crypto_freereq(crp); 1124 AHSTAT_INC(ahs_hist[sav->alg_auth]); 1125 #ifdef REGRESSION 1126 /* Emulate man-in-the-middle attack when ipsec_integrity is TRUE. */ 1127 if (V_ipsec_integrity) { 1128 int alen; 1129 1130 /* 1131 * Corrupt HMAC if we want to test integrity verification of 1132 * the other side. 1133 */ 1134 alen = AUTHSIZE(sav); 1135 m_copyback(m, m->m_pkthdr.len - alen, alen, ipseczeroes); 1136 } 1137 #endif 1138 1139 /* NB: m is reclaimed by ipsec_process_done. */ 1140 error = ipsec_process_done(m, sp, sav, idx); 1141 CURVNET_RESTORE(); 1142 return (error); 1143 bad: 1144 CURVNET_RESTORE(); 1145 free(xd, M_XDATA); 1146 crypto_freereq(crp); 1147 key_freesav(&sav); 1148 key_freesp(&sp); 1149 return (error); 1150 } 1151 1152 static struct xformsw ah_xformsw = { 1153 .xf_type = XF_AH, 1154 .xf_name = "IPsec AH", 1155 .xf_init = ah_init, 1156 .xf_cleanup = ah_cleanup, 1157 .xf_input = ah_input, 1158 .xf_output = ah_output, 1159 }; 1160 1161 SYSINIT(ah_xform_init, SI_SUB_PROTO_DOMAIN, SI_ORDER_MIDDLE, 1162 xform_attach, &ah_xformsw); 1163 SYSUNINIT(ah_xform_uninit, SI_SUB_PROTO_DOMAIN, SI_ORDER_MIDDLE, 1164 xform_detach, &ah_xformsw); 1165