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