1 /* $NetBSD: xform_ah.c,v 1.107 2019/01/27 02:08:48 pgoyette Exp $ */ 2 /* $FreeBSD: xform_ah.c,v 1.1.4.1 2003/01/24 05:11:36 sam Exp $ */ 3 /* $OpenBSD: ip_ah.c,v 1.63 2001/06/26 06:18:58 angelos Exp $ */ 4 /* 5 * The authors of this code are John Ioannidis (ji@tla.org), 6 * Angelos D. Keromytis (kermit@csd.uch.gr) and 7 * Niels Provos (provos@physnet.uni-hamburg.de). 8 * 9 * The original version of this code was written by John Ioannidis 10 * for BSD/OS in Athens, Greece, in November 1995. 11 * 12 * Ported to OpenBSD and NetBSD, with additional transforms, in December 1996, 13 * by Angelos D. Keromytis. 14 * 15 * Additional transforms and features in 1997 and 1998 by Angelos D. Keromytis 16 * and Niels Provos. 17 * 18 * Additional features in 1999 by Angelos D. Keromytis and Niklas Hallqvist. 19 * 20 * Copyright (c) 1995, 1996, 1997, 1998, 1999 by John Ioannidis, 21 * Angelos D. Keromytis and Niels Provos. 22 * Copyright (c) 1999 Niklas Hallqvist. 23 * Copyright (c) 2001 Angelos D. Keromytis. 24 * 25 * Permission to use, copy, and modify this software with or without fee 26 * is hereby granted, provided that this entire notice is included in 27 * all copies of any software which is or includes a copy or 28 * modification of this software. 29 * You may use this code under the GNU public license if you so wish. Please 30 * contribute changes back to the authors under this freer than GPL license 31 * so that we may further the use of strong encryption without limitations to 32 * all. 33 * 34 * THIS SOFTWARE IS BEING PROVIDED "AS IS", WITHOUT ANY EXPRESS OR 35 * IMPLIED WARRANTY. IN PARTICULAR, NONE OF THE AUTHORS MAKES ANY 36 * REPRESENTATION OR WARRANTY OF ANY KIND CONCERNING THE 37 * MERCHANTABILITY OF THIS SOFTWARE OR ITS FITNESS FOR ANY PARTICULAR 38 * PURPOSE. 39 */ 40 41 #include <sys/cdefs.h> 42 __KERNEL_RCSID(0, "$NetBSD: xform_ah.c,v 1.107 2019/01/27 02:08:48 pgoyette Exp $"); 43 44 #if defined(_KERNEL_OPT) 45 #include "opt_inet.h" 46 #include "opt_ipsec.h" 47 #endif 48 49 #include <sys/param.h> 50 #include <sys/systm.h> 51 #include <sys/mbuf.h> 52 #include <sys/socket.h> 53 #include <sys/syslog.h> 54 #include <sys/kernel.h> 55 #include <sys/sysctl.h> 56 #include <sys/pool.h> 57 #include <sys/pserialize.h> 58 #include <sys/kmem.h> 59 60 #include <net/if.h> 61 62 #include <netinet/in.h> 63 #include <netinet/in_systm.h> 64 #include <netinet/ip.h> 65 #include <netinet/ip_ecn.h> 66 #include <netinet/ip_var.h> 67 #include <netinet/ip6.h> 68 69 #include <net/route.h> 70 #include <netipsec/ipsec.h> 71 #include <netipsec/ipsec_private.h> 72 #include <netipsec/ah.h> 73 #include <netipsec/ah_var.h> 74 #include <netipsec/xform.h> 75 76 #ifdef INET6 77 #include <netinet6/ip6_var.h> 78 #include <netinet6/scope6_var.h> 79 #include <netipsec/ipsec6.h> 80 #endif 81 82 #include <netipsec/key.h> 83 #include <netipsec/key_debug.h> 84 85 #include <opencrypto/cryptodev.h> 86 87 /* 88 * Return header size in bytes. The old protocol did not support 89 * the replay counter; the new protocol always includes the counter. 90 */ 91 #define HDRSIZE(sav) \ 92 (((sav)->flags & SADB_X_EXT_OLD) ? \ 93 sizeof(struct ah) : sizeof(struct ah) + sizeof(uint32_t)) 94 /* 95 * Return authenticator size in bytes. The old protocol is known 96 * to use a fixed 16-byte authenticator. The new algorithm gets 97 * this size from the xform but is (currently) always 12. 98 */ 99 #define AUTHSIZE(sav) \ 100 ((sav->flags & SADB_X_EXT_OLD) ? 16 : (sav)->tdb_authalgxform->authsize) 101 102 percpu_t *ahstat_percpu; 103 104 int ah_enable = 1; /* control flow of packets with AH */ 105 int ip4_ah_cleartos = 1; /* clear ip_tos when doing AH calc */ 106 107 static const char ipseczeroes[256]; 108 109 int ah_max_authsize; /* max authsize over all algorithms */ 110 111 static int ah_input_cb(struct cryptop *); 112 static int ah_output_cb(struct cryptop *); 113 114 const uint8_t ah_stats[256] = { SADB_AALG_STATS_INIT }; 115 116 static pool_cache_t ah_tdb_crypto_pool_cache; 117 static size_t ah_pool_item_size; 118 119 /* 120 * NB: this is public for use by the PF_KEY support. 121 */ 122 const struct auth_hash * 123 ah_algorithm_lookup(int alg) 124 { 125 126 switch (alg) { 127 case SADB_X_AALG_NULL: 128 return &auth_hash_null; 129 case SADB_AALG_MD5HMAC: 130 return &auth_hash_hmac_md5_96; 131 case SADB_AALG_SHA1HMAC: 132 return &auth_hash_hmac_sha1_96; 133 case SADB_X_AALG_RIPEMD160HMAC: 134 return &auth_hash_hmac_ripemd_160_96; 135 case SADB_X_AALG_MD5: 136 return &auth_hash_key_md5; 137 case SADB_X_AALG_SHA: 138 return &auth_hash_key_sha1; 139 case SADB_X_AALG_SHA2_256: 140 return &auth_hash_hmac_sha2_256; 141 case SADB_X_AALG_SHA2_384: 142 return &auth_hash_hmac_sha2_384; 143 case SADB_X_AALG_SHA2_512: 144 return &auth_hash_hmac_sha2_512; 145 case SADB_X_AALG_AES_XCBC_MAC: 146 return &auth_hash_aes_xcbc_mac_96; 147 } 148 return NULL; 149 } 150 151 size_t 152 ah_authsiz(const struct secasvar *sav) 153 { 154 size_t size; 155 156 if (sav == NULL) { 157 return ah_max_authsize; 158 } 159 160 size = AUTHSIZE(sav); 161 return roundup(size, sizeof(uint32_t)); 162 } 163 164 size_t 165 ah_hdrsiz(const struct secasvar *sav) 166 { 167 size_t size; 168 169 if (sav != NULL) { 170 int authsize, rplen, align; 171 172 KASSERT(sav->tdb_authalgxform != NULL); 173 /*XXX not right for null algorithm--does it matter??*/ 174 175 /* RFC4302: use the correct alignment. */ 176 align = sizeof(uint32_t); 177 #ifdef INET6 178 if (sav->sah->saidx.dst.sa.sa_family == AF_INET6) { 179 align = sizeof(uint64_t); 180 } 181 #endif 182 rplen = HDRSIZE(sav); 183 authsize = AUTHSIZE(sav); 184 size = roundup(rplen + authsize, align); 185 } else { 186 /* default guess */ 187 size = sizeof(struct ah) + sizeof(uint32_t) + ah_max_authsize; 188 } 189 return size; 190 } 191 192 /* 193 * NB: public for use by esp_init. 194 */ 195 int 196 ah_init0(struct secasvar *sav, const struct xformsw *xsp, 197 struct cryptoini *cria) 198 { 199 const struct auth_hash *thash; 200 int keylen; 201 202 thash = ah_algorithm_lookup(sav->alg_auth); 203 if (thash == NULL) { 204 DPRINTF(("%s: unsupported authentication algorithm %u\n", 205 __func__, sav->alg_auth)); 206 return EINVAL; 207 } 208 /* 209 * Verify the replay state block allocation is consistent with 210 * the protocol type. We check here so we can make assumptions 211 * later during protocol processing. 212 */ 213 /* NB: replay state is setup elsewhere (sigh) */ 214 if (((sav->flags&SADB_X_EXT_OLD) == 0) ^ (sav->replay != NULL)) { 215 DPRINTF(("%s: replay state block inconsistency, " 216 "%s algorithm %s replay state\n", __func__, 217 (sav->flags & SADB_X_EXT_OLD) ? "old" : "new", 218 sav->replay == NULL ? "without" : "with")); 219 return EINVAL; 220 } 221 if (sav->key_auth == NULL) { 222 DPRINTF(("%s: no authentication key for %s algorithm\n", 223 __func__, thash->name)); 224 return EINVAL; 225 } 226 keylen = _KEYLEN(sav->key_auth); 227 if (keylen != thash->keysize && thash->keysize != 0) { 228 DPRINTF(("%s: invalid keylength %d, algorithm %s requires " 229 "keysize %d\n", __func__, 230 keylen, thash->name, thash->keysize)); 231 return EINVAL; 232 } 233 234 sav->tdb_xform = xsp; 235 sav->tdb_authalgxform = thash; 236 237 /* Initialize crypto session. */ 238 memset(cria, 0, sizeof(*cria)); 239 cria->cri_alg = sav->tdb_authalgxform->type; 240 cria->cri_klen = _KEYBITS(sav->key_auth); 241 cria->cri_key = _KEYBUF(sav->key_auth); 242 243 return 0; 244 } 245 246 /* 247 * ah_init() is called when an SPI is being set up. 248 */ 249 static int 250 ah_init(struct secasvar *sav, const struct xformsw *xsp) 251 { 252 struct cryptoini cria; 253 int error; 254 255 error = ah_init0(sav, xsp, &cria); 256 if (!error) 257 error = crypto_newsession(&sav->tdb_cryptoid, 258 &cria, crypto_support); 259 return error; 260 } 261 262 /* 263 * Paranoia. 264 * 265 * NB: public for use by esp_zeroize (XXX). 266 */ 267 int 268 ah_zeroize(struct secasvar *sav) 269 { 270 int err; 271 272 if (sav->key_auth) { 273 explicit_memset(_KEYBUF(sav->key_auth), 0, 274 _KEYLEN(sav->key_auth)); 275 } 276 277 err = crypto_freesession(sav->tdb_cryptoid); 278 sav->tdb_cryptoid = 0; 279 sav->tdb_authalgxform = NULL; 280 sav->tdb_xform = NULL; 281 return err; 282 } 283 284 /* 285 * Massage IPv4/IPv6 headers for AH processing. 286 */ 287 static int 288 ah_massage_headers(struct mbuf **m0, int proto, int skip, int alg, int out) 289 { 290 struct mbuf *m = *m0; 291 unsigned char *ptr; 292 int off, optlen; 293 #ifdef INET 294 struct ip *ip; 295 #endif 296 #ifdef INET6 297 int count, ip6optlen; 298 struct ip6_ext *ip6e; 299 struct ip6_hdr ip6; 300 int alloc, nxt; 301 #endif 302 303 switch (proto) { 304 #ifdef INET 305 case AF_INET: 306 /* 307 * This is the least painful way of dealing with IPv4 header 308 * and option processing -- just make sure they're in 309 * contiguous memory. 310 */ 311 *m0 = m = m_pullup(m, skip); 312 if (m == NULL) { 313 DPRINTF(("%s: m_pullup failed\n", __func__)); 314 return ENOBUFS; 315 } 316 317 /* Fix the IP header */ 318 ip = mtod(m, struct ip *); 319 if (ip4_ah_cleartos) 320 ip->ip_tos = 0; 321 ip->ip_ttl = 0; 322 ip->ip_sum = 0; 323 ip->ip_off = htons(ntohs(ip->ip_off) & ip4_ah_offsetmask); 324 325 if (alg == CRYPTO_MD5_KPDK || alg == CRYPTO_SHA1_KPDK) 326 ip->ip_off &= htons(IP_DF); 327 else 328 ip->ip_off = 0; 329 330 ptr = mtod(m, unsigned char *); 331 332 /* IPv4 option processing */ 333 for (off = sizeof(struct ip); off < skip;) { 334 if (ptr[off] == IPOPT_EOL) { 335 break; 336 } else if (ptr[off] == IPOPT_NOP) { 337 optlen = 1; 338 } else if (off + 1 < skip) { 339 optlen = ptr[off + 1]; 340 if (optlen < 2 || off + optlen > skip) { 341 m_freem(m); 342 return EINVAL; 343 } 344 } else { 345 m_freem(m); 346 return EINVAL; 347 } 348 349 switch (ptr[off]) { 350 case IPOPT_NOP: 351 case IPOPT_SECURITY: 352 case 0x85: /* Extended security. */ 353 case 0x86: /* Commercial security. */ 354 case 0x94: /* Router alert */ 355 case 0x95: /* RFC1770 */ 356 break; 357 358 case IPOPT_LSRR: 359 case IPOPT_SSRR: 360 /* 361 * On output, if we have either of the 362 * source routing options, we should 363 * swap the destination address of the 364 * IP header with the last address 365 * specified in the option, as that is 366 * what the destination's IP header 367 * will look like. 368 */ 369 if (out) 370 memcpy(&ip->ip_dst, 371 ptr + off + optlen - 372 sizeof(struct in_addr), 373 sizeof(struct in_addr)); 374 /* FALLTHROUGH */ 375 376 default: 377 /* Zeroize all other options. */ 378 memset(ptr + off, 0, optlen); 379 break; 380 } 381 382 off += optlen; 383 384 /* Sanity check. */ 385 if (off > skip) { 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), &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), &ip6); 419 420 ip6optlen = skip - sizeof(struct ip6_hdr); 421 422 /* Let's deal with the remaining headers (if any). */ 423 if (ip6optlen > 0) { 424 if (m->m_len <= skip) { 425 ptr = malloc(ip6optlen, M_XDATA, M_NOWAIT); 426 if (ptr == NULL) { 427 DPRINTF(("%s: failed to allocate " 428 "memory for IPv6 headers\n", 429 __func__)); 430 m_freem(m); 431 return ENOBUFS; 432 } 433 434 /* 435 * Copy all the protocol headers after 436 * the IPv6 header. 437 */ 438 m_copydata(m, sizeof(struct ip6_hdr), 439 ip6optlen, ptr); 440 alloc = 1; 441 } else { 442 /* No need to allocate memory. */ 443 ptr = mtod(m, unsigned char *) + 444 sizeof(struct ip6_hdr); 445 alloc = 0; 446 } 447 } else 448 break; 449 450 nxt = ip6.ip6_nxt & 0xff; /* Next header type. */ 451 452 for (off = 0; off < ip6optlen;) { 453 int noff; 454 455 if (off + sizeof(*ip6e) > ip6optlen) { 456 goto error6; 457 } 458 ip6e = (struct ip6_ext *)(ptr + off); 459 noff = off + ((ip6e->ip6e_len + 1) << 3); 460 if (noff > ip6optlen) { 461 goto error6; 462 } 463 464 switch (nxt) { 465 case IPPROTO_HOPOPTS: 466 case IPPROTO_DSTOPTS: 467 /* Zero out mutable options. */ 468 for (count = off + sizeof(struct ip6_ext); 469 count < noff;) { 470 if (ptr[count] == IP6OPT_PAD1) { 471 count++; 472 continue; 473 } 474 475 if (count + 1 >= noff) { 476 goto error6; 477 } 478 optlen = ptr[count + 1] + 2; 479 480 if (count + optlen > noff) { 481 goto error6; 482 } 483 484 if (ptr[count] & IP6OPT_MUTABLE) { 485 memset(ptr + count, 0, optlen); 486 } 487 488 count += optlen; 489 } 490 if (count != noff) { 491 goto error6; 492 } 493 /* FALLTHROUGH */ 494 495 case IPPROTO_ROUTING: 496 /* Advance. */ 497 off = noff; 498 nxt = ip6e->ip6e_nxt; 499 break; 500 501 default: 502 error6: 503 if (alloc) 504 free(ptr, M_XDATA); 505 m_freem(m); 506 return EINVAL; 507 } 508 } 509 510 /* Copyback and free, if we allocated. */ 511 if (alloc) { 512 m_copyback(m, sizeof(struct ip6_hdr), ip6optlen, 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 const struct auth_hash *ahx; 531 struct tdb_crypto *tc = NULL; 532 struct newah *ah; 533 int hl, rplen, authsize, ahsize, error, stat = AH_STAT_HDROPS; 534 struct cryptodesc *crda; 535 struct cryptop *crp = NULL; 536 bool pool_used; 537 uint8_t nxt; 538 539 KASSERT(sav != NULL); 540 KASSERT(sav->key_auth != NULL); 541 KASSERT(sav->tdb_authalgxform != NULL); 542 543 /* Figure out header size. */ 544 rplen = HDRSIZE(sav); 545 546 /* XXX don't pullup, just copy header */ 547 M_REGION_GET(ah, struct newah *, m, skip, rplen); 548 if (ah == NULL) { 549 /* m already freed */ 550 return ENOBUFS; 551 } 552 553 nxt = ah->ah_nxt; 554 555 /* Check replay window, if applicable. */ 556 if (sav->replay && !ipsec_chkreplay(ntohl(ah->ah_seq), sav)) { 557 char buf[IPSEC_LOGSASTRLEN]; 558 DPRINTF(("%s: packet replay failure: %s\n", __func__, 559 ipsec_logsastr(sav, buf, sizeof(buf)))); 560 stat = AH_STAT_REPLAY; 561 error = EACCES; 562 goto bad; 563 } 564 565 /* Verify AH header length. */ 566 hl = sizeof(struct ah) + (ah->ah_len * sizeof(uint32_t)); 567 ahx = sav->tdb_authalgxform; 568 authsize = AUTHSIZE(sav); 569 ahsize = ah_hdrsiz(sav); 570 if (hl != ahsize) { 571 char buf[IPSEC_ADDRSTRLEN]; 572 DPRINTF(("%s: bad authenticator length %u (expecting %lu)" 573 " for packet in SA %s/%08lx\n", __func__, 574 hl, (u_long)ahsize, 575 ipsec_address(&sav->sah->saidx.dst, buf, sizeof(buf)), 576 (u_long) ntohl(sav->spi))); 577 stat = AH_STAT_BADAUTHL; 578 error = EACCES; 579 goto bad; 580 } 581 if (skip + ahsize > m->m_pkthdr.len) { 582 char buf[IPSEC_ADDRSTRLEN]; 583 DPRINTF(("%s: bad mbuf length %u (expecting >= %lu)" 584 " for packet in SA %s/%08lx\n", __func__, 585 m->m_pkthdr.len, (u_long)(skip + ahsize), 586 ipsec_address(&sav->sah->saidx.dst, buf, sizeof(buf)), 587 (u_long) ntohl(sav->spi))); 588 stat = AH_STAT_BADAUTHL; 589 error = EACCES; 590 goto bad; 591 } 592 593 AH_STATADD(AH_STAT_IBYTES, m->m_pkthdr.len - skip - hl); 594 595 /* Get crypto descriptors. */ 596 crp = crypto_getreq(1); 597 if (crp == NULL) { 598 DPRINTF(("%s: failed to acquire crypto descriptor\n", __func__)); 599 stat = AH_STAT_CRYPTO; 600 error = ENOBUFS; 601 goto bad; 602 } 603 604 crda = crp->crp_desc; 605 KASSERT(crda != NULL); 606 607 crda->crd_skip = 0; 608 crda->crd_len = m->m_pkthdr.len; 609 crda->crd_inject = skip + rplen; 610 611 /* Authentication operation. */ 612 crda->crd_alg = ahx->type; 613 crda->crd_key = _KEYBUF(sav->key_auth); 614 crda->crd_klen = _KEYBITS(sav->key_auth); 615 616 /* Allocate IPsec-specific opaque crypto info. */ 617 size_t size = sizeof(*tc); 618 size_t extra = skip + rplen + authsize; 619 size += extra; 620 621 if (__predict_true(size <= ah_pool_item_size)) { 622 tc = pool_cache_get(ah_tdb_crypto_pool_cache, PR_NOWAIT); 623 pool_used = true; 624 } else { 625 /* size can exceed on IPv6 packets with large options. */ 626 tc = kmem_intr_zalloc(size, KM_NOSLEEP); 627 pool_used = false; 628 } 629 if (tc == NULL) { 630 DPRINTF(("%s: failed to allocate tdb_crypto\n", __func__)); 631 stat = AH_STAT_CRYPTO; 632 error = ENOBUFS; 633 goto bad; 634 } 635 636 error = m_makewritable(&m, 0, extra, M_NOWAIT); 637 if (error) { 638 DPRINTF(("%s: failed to m_makewritable\n", __func__)); 639 goto bad; 640 } 641 642 /* 643 * Save the authenticator, the skipped portion of the packet, 644 * and the AH header. 645 */ 646 m_copydata(m, 0, extra, (tc + 1)); 647 /* Zeroize the authenticator on the packet. */ 648 m_copyback(m, skip + rplen, authsize, ipseczeroes); 649 650 /* "Massage" the packet headers for crypto processing. */ 651 error = ah_massage_headers(&m, sav->sah->saidx.dst.sa.sa_family, 652 skip, ahx->type, 0); 653 if (error != 0) { 654 /* NB: mbuf is free'd by ah_massage_headers */ 655 m = NULL; 656 goto bad; 657 } 658 659 { 660 int s = pserialize_read_enter(); 661 662 /* 663 * Take another reference to the SA for opencrypto callback. 664 */ 665 if (__predict_false(sav->state == SADB_SASTATE_DEAD)) { 666 pserialize_read_exit(s); 667 stat = AH_STAT_NOTDB; 668 error = ENOENT; 669 goto bad; 670 } 671 KEY_SA_REF(sav); 672 pserialize_read_exit(s); 673 } 674 675 /* Crypto operation descriptor. */ 676 crp->crp_ilen = m->m_pkthdr.len; /* Total input length. */ 677 crp->crp_flags = CRYPTO_F_IMBUF; 678 crp->crp_buf = m; 679 crp->crp_callback = ah_input_cb; 680 crp->crp_sid = sav->tdb_cryptoid; 681 crp->crp_opaque = tc; 682 683 /* These are passed as-is to the callback. */ 684 tc->tc_spi = sav->spi; 685 tc->tc_dst = sav->sah->saidx.dst; 686 tc->tc_proto = sav->sah->saidx.proto; 687 tc->tc_nxt = nxt; 688 tc->tc_protoff = protoff; 689 tc->tc_skip = skip; 690 tc->tc_sav = sav; 691 692 DPRINTF(("%s: hash over %d bytes, skip %d: " 693 "crda len %d skip %d inject %d\n", __func__, 694 crp->crp_ilen, tc->tc_skip, 695 crda->crd_len, crda->crd_skip, crda->crd_inject)); 696 697 return crypto_dispatch(crp); 698 699 bad: 700 if (tc != NULL) { 701 if (__predict_true(pool_used)) 702 pool_cache_put(ah_tdb_crypto_pool_cache, tc); 703 else 704 kmem_intr_free(tc, size); 705 } 706 if (crp != NULL) 707 crypto_freereq(crp); 708 if (m != NULL) 709 m_freem(m); 710 AH_STATINC(stat); 711 return error; 712 } 713 714 #ifdef INET6 715 #define IPSEC_COMMON_INPUT_CB(m, sav, skip, protoff) do { \ 716 if (saidx->dst.sa.sa_family == AF_INET6) { \ 717 error = ipsec6_common_input_cb(m, sav, skip, protoff); \ 718 } else { \ 719 error = ipsec4_common_input_cb(m, sav, skip, protoff); \ 720 } \ 721 } while (0) 722 #else 723 #define IPSEC_COMMON_INPUT_CB(m, sav, skip, protoff) \ 724 (error = ipsec4_common_input_cb(m, sav, skip, protoff)) 725 #endif 726 727 /* 728 * AH input callback from the crypto driver. 729 */ 730 static int 731 ah_input_cb(struct cryptop *crp) 732 { 733 char buf[IPSEC_ADDRSTRLEN]; 734 int rplen, ahsize, error, skip, protoff; 735 unsigned char calc[AH_ALEN_MAX]; 736 struct mbuf *m; 737 struct tdb_crypto *tc; 738 struct secasvar *sav; 739 struct secasindex *saidx; 740 uint8_t nxt; 741 char *ptr; 742 int authsize; 743 bool pool_used; 744 size_t size; 745 IPSEC_DECLARE_LOCK_VARIABLE; 746 747 KASSERT(crp->crp_opaque != NULL); 748 tc = crp->crp_opaque; 749 skip = tc->tc_skip; 750 nxt = tc->tc_nxt; 751 protoff = tc->tc_protoff; 752 m = crp->crp_buf; 753 754 IPSEC_ACQUIRE_GLOBAL_LOCKS(); 755 756 sav = tc->tc_sav; 757 saidx = &sav->sah->saidx; 758 KASSERTMSG(saidx->dst.sa.sa_family == AF_INET || 759 saidx->dst.sa.sa_family == AF_INET6, 760 "unexpected protocol family %u", saidx->dst.sa.sa_family); 761 762 /* Figure out header size. */ 763 rplen = HDRSIZE(sav); 764 authsize = AUTHSIZE(sav); 765 ahsize = ah_hdrsiz(sav); 766 767 size = sizeof(*tc) + skip + rplen + authsize; 768 if (__predict_true(size <= ah_pool_item_size)) 769 pool_used = true; 770 else 771 pool_used = false; 772 773 /* Check for crypto errors. */ 774 if (crp->crp_etype) { 775 if (sav->tdb_cryptoid != 0) 776 sav->tdb_cryptoid = crp->crp_sid; 777 778 if (crp->crp_etype == EAGAIN) { 779 IPSEC_RELEASE_GLOBAL_LOCKS(); 780 return crypto_dispatch(crp); 781 } 782 783 AH_STATINC(AH_STAT_NOXFORM); 784 DPRINTF(("%s: crypto error %d\n", __func__, crp->crp_etype)); 785 error = crp->crp_etype; 786 goto bad; 787 } else { 788 AH_STATINC(AH_STAT_HIST + ah_stats[sav->alg_auth]); 789 crypto_freereq(crp); /* No longer needed. */ 790 crp = NULL; 791 } 792 793 if (ipsec_debug) 794 memset(calc, 0, sizeof(calc)); 795 796 /* Copy authenticator off the packet. */ 797 m_copydata(m, skip + rplen, authsize, calc); 798 799 ptr = (char *)(tc + 1); 800 const uint8_t *pppp = ptr + skip + rplen; 801 802 /* Verify authenticator. */ 803 if (!consttime_memequal(pppp, calc, authsize)) { 804 DPRINTF(("%s: authentication hash mismatch " \ 805 "over %d bytes " \ 806 "for packet in SA %s/%08lx:\n" \ 807 "%02x%02x:%02x%02x:%02x%02x:%02x%02x:%02x%02x:%02x%02x, " \ 808 "%02x%02x:%02x%02x:%02x%02x:%02x%02x:%02x%02x:%02x%02x\n", 809 __func__, authsize, 810 ipsec_address(&saidx->dst, buf, sizeof(buf)), 811 (u_long) ntohl(sav->spi), 812 calc[0], calc[1], calc[2], calc[3], 813 calc[4], calc[5], calc[6], calc[7], 814 calc[8], calc[9], calc[10], calc[11], 815 pppp[0], pppp[1], pppp[2], pppp[3], 816 pppp[4], pppp[5], pppp[6], pppp[7], 817 pppp[8], pppp[9], pppp[10], pppp[11] 818 )); 819 AH_STATINC(AH_STAT_BADAUTH); 820 error = EACCES; 821 goto bad; 822 } 823 824 /* Fix the Next Protocol field. */ 825 ptr[protoff] = nxt; 826 827 /* Copyback the saved (uncooked) network headers. */ 828 m_copyback(m, 0, skip, ptr); 829 830 if (__predict_true(pool_used)) 831 pool_cache_put(ah_tdb_crypto_pool_cache, tc); 832 else 833 kmem_intr_free(tc, size); 834 tc = NULL; 835 836 /* 837 * Header is now authenticated. 838 */ 839 m->m_flags |= M_AUTHIPHDR; 840 841 /* 842 * Update replay sequence number, if appropriate. 843 */ 844 if (sav->replay) { 845 uint32_t seq; 846 847 m_copydata(m, skip + offsetof(struct newah, ah_seq), 848 sizeof(seq), &seq); 849 if (ipsec_updatereplay(ntohl(seq), sav)) { 850 AH_STATINC(AH_STAT_REPLAY); 851 error = EACCES; 852 goto bad; 853 } 854 } 855 856 /* 857 * Remove the AH header and authenticator from the mbuf. 858 */ 859 error = m_striphdr(m, skip, ahsize); 860 if (error) { 861 DPRINTF(("%s: mangled mbuf chain for SA %s/%08lx\n", __func__, 862 ipsec_address(&saidx->dst, buf, sizeof(buf)), 863 (u_long) ntohl(sav->spi))); 864 865 AH_STATINC(AH_STAT_HDROPS); 866 goto bad; 867 } 868 869 IPSEC_COMMON_INPUT_CB(m, sav, skip, protoff); 870 871 KEY_SA_UNREF(&sav); 872 IPSEC_RELEASE_GLOBAL_LOCKS(); 873 return error; 874 875 bad: 876 if (sav) 877 KEY_SA_UNREF(&sav); 878 IPSEC_RELEASE_GLOBAL_LOCKS(); 879 if (m != NULL) 880 m_freem(m); 881 if (tc != NULL) { 882 if (pool_used) 883 pool_cache_put(ah_tdb_crypto_pool_cache, tc); 884 else 885 kmem_intr_free(tc, size); 886 } 887 if (crp != NULL) 888 crypto_freereq(crp); 889 return error; 890 } 891 892 /* 893 * AH output routine, called by ipsec[46]_process_packet(). 894 */ 895 static int 896 ah_output(struct mbuf *m, const struct ipsecrequest *isr, struct secasvar *sav, 897 int skip, int protoff) 898 { 899 char buf[IPSEC_ADDRSTRLEN]; 900 const struct auth_hash *ahx; 901 struct cryptodesc *crda; 902 struct tdb_crypto *tc; 903 struct mbuf *mi; 904 struct cryptop *crp; 905 uint16_t iplen; 906 int error, rplen, authsize, ahsize, maxpacketsize, roff; 907 uint8_t prot; 908 struct newah *ah; 909 size_t ipoffs; 910 bool pool_used; 911 912 KASSERT(sav != NULL); 913 KASSERT(sav->tdb_authalgxform != NULL); 914 ahx = sav->tdb_authalgxform; 915 916 AH_STATINC(AH_STAT_OUTPUT); 917 918 /* Figure out header size. */ 919 rplen = HDRSIZE(sav); 920 authsize = AUTHSIZE(sav); 921 ahsize = ah_hdrsiz(sav); 922 923 /* Check for maximum packet size violations. */ 924 switch (sav->sah->saidx.dst.sa.sa_family) { 925 #ifdef INET 926 case AF_INET: 927 maxpacketsize = IP_MAXPACKET; 928 ipoffs = offsetof(struct ip, ip_len); 929 break; 930 #endif 931 #ifdef INET6 932 case AF_INET6: 933 maxpacketsize = IPV6_MAXPACKET; 934 ipoffs = offsetof(struct ip6_hdr, ip6_plen); 935 break; 936 #endif 937 default: 938 DPRINTF(("%s: unknown/unsupported protocol " 939 "family %u, SA %s/%08lx\n", __func__, 940 sav->sah->saidx.dst.sa.sa_family, 941 ipsec_address(&sav->sah->saidx.dst, buf, sizeof(buf)), 942 (u_long) ntohl(sav->spi))); 943 AH_STATINC(AH_STAT_NOPF); 944 error = EPFNOSUPPORT; 945 goto bad; 946 } 947 if (ahsize + m->m_pkthdr.len > maxpacketsize) { 948 DPRINTF(("%s: packet in SA %s/%08lx got too big " 949 "(len %u, max len %u)\n", __func__, 950 ipsec_address(&sav->sah->saidx.dst, buf, sizeof(buf)), 951 (u_long) ntohl(sav->spi), 952 ahsize + m->m_pkthdr.len, maxpacketsize)); 953 AH_STATINC(AH_STAT_TOOBIG); 954 error = EMSGSIZE; 955 goto bad; 956 } 957 958 /* Update the counters. */ 959 AH_STATADD(AH_STAT_OBYTES, m->m_pkthdr.len - skip); 960 961 m = m_clone(m); 962 if (m == NULL) { 963 DPRINTF(("%s: cannot clone mbuf chain, SA %s/%08lx\n", __func__, 964 ipsec_address(&sav->sah->saidx.dst, buf, sizeof(buf)), 965 (u_long) ntohl(sav->spi))); 966 AH_STATINC(AH_STAT_HDROPS); 967 error = ENOBUFS; 968 goto bad; 969 } 970 971 /* Inject AH header. */ 972 mi = m_makespace(m, skip, ahsize, &roff); 973 if (mi == NULL) { 974 DPRINTF(("%s: failed to inject %u byte AH header for SA " 975 "%s/%08lx\n", __func__, ahsize, 976 ipsec_address(&sav->sah->saidx.dst, buf, sizeof(buf)), 977 (u_long) ntohl(sav->spi))); 978 AH_STATINC(AH_STAT_HDROPS); 979 error = ENOBUFS; 980 goto bad; 981 } 982 983 /* 984 * The AH header is guaranteed by m_makespace() to be in 985 * contiguous memory, at roff bytes offset into the returned mbuf. 986 */ 987 ah = (struct newah *)(mtod(mi, char *) + roff); 988 989 /* Initialize the AH header. */ 990 m_copydata(m, protoff, sizeof(uint8_t), &ah->ah_nxt); 991 ah->ah_len = (ahsize - sizeof(struct ah)) / sizeof(uint32_t); 992 ah->ah_reserve = 0; 993 ah->ah_spi = sav->spi; 994 995 /* Zeroize authenticator. */ 996 m_copyback(m, skip + rplen, authsize, ipseczeroes); 997 998 /* Zeroize padding. */ 999 m_copyback(m, skip + rplen + authsize, ahsize - (rplen + authsize), 1000 ipseczeroes); 1001 1002 /* Insert packet replay counter, as requested. */ 1003 if (sav->replay) { 1004 if (sav->replay->count == ~0 && 1005 (sav->flags & SADB_X_EXT_CYCSEQ) == 0) { 1006 DPRINTF(("%s: replay counter wrapped for SA %s/%08lx\n", 1007 __func__, ipsec_address(&sav->sah->saidx.dst, buf, 1008 sizeof(buf)), (u_long) ntohl(sav->spi))); 1009 AH_STATINC(AH_STAT_WRAP); 1010 error = EINVAL; 1011 goto bad; 1012 } 1013 #ifdef IPSEC_DEBUG 1014 /* Emulate replay attack when ipsec_replay is TRUE. */ 1015 if (!ipsec_replay) 1016 #endif 1017 sav->replay->count++; 1018 ah->ah_seq = htonl(sav->replay->count); 1019 } 1020 1021 /* Get crypto descriptors. */ 1022 crp = crypto_getreq(1); 1023 if (crp == NULL) { 1024 DPRINTF(("%s: failed to acquire crypto descriptors\n", 1025 __func__)); 1026 AH_STATINC(AH_STAT_CRYPTO); 1027 error = ENOBUFS; 1028 goto bad; 1029 } 1030 1031 crda = crp->crp_desc; 1032 1033 crda->crd_skip = 0; 1034 crda->crd_inject = skip + rplen; 1035 crda->crd_len = m->m_pkthdr.len; 1036 1037 /* Authentication operation. */ 1038 crda->crd_alg = ahx->type; 1039 crda->crd_key = _KEYBUF(sav->key_auth); 1040 crda->crd_klen = _KEYBITS(sav->key_auth); 1041 1042 /* Allocate IPsec-specific opaque crypto info. */ 1043 size_t size = sizeof(*tc) + skip; 1044 1045 if (__predict_true(size <= ah_pool_item_size)) { 1046 tc = pool_cache_get(ah_tdb_crypto_pool_cache, PR_NOWAIT); 1047 pool_used = true; 1048 } else { 1049 /* size can exceed on IPv6 packets with large options. */ 1050 tc = kmem_intr_zalloc(size, KM_NOSLEEP); 1051 pool_used = false; 1052 } 1053 if (tc == NULL) { 1054 DPRINTF(("%s: failed to allocate tdb_crypto\n", __func__)); 1055 AH_STATINC(AH_STAT_CRYPTO); 1056 error = ENOBUFS; 1057 goto bad_crp; 1058 } 1059 1060 uint8_t *pext = (char *)(tc + 1); 1061 /* Save the skipped portion of the packet. */ 1062 m_copydata(m, 0, skip, pext); 1063 1064 /* 1065 * Fix IP header length on the header used for 1066 * authentication. We don't need to fix the original 1067 * header length as it will be fixed by our caller. 1068 */ 1069 memcpy(&iplen, pext + ipoffs, sizeof(iplen)); 1070 iplen = htons(ntohs(iplen) + ahsize); 1071 m_copyback(m, ipoffs, sizeof(iplen), &iplen); 1072 1073 /* Fix the Next Header field in saved header. */ 1074 pext[protoff] = IPPROTO_AH; 1075 1076 /* Update the Next Protocol field in the IP header. */ 1077 prot = IPPROTO_AH; 1078 m_copyback(m, protoff, sizeof(prot), &prot); 1079 1080 /* "Massage" the packet headers for crypto processing. */ 1081 error = ah_massage_headers(&m, sav->sah->saidx.dst.sa.sa_family, 1082 skip, ahx->type, 1); 1083 if (error != 0) { 1084 m = NULL; /* mbuf was free'd by ah_massage_headers. */ 1085 goto bad_tc; 1086 } 1087 1088 { 1089 int s = pserialize_read_enter(); 1090 1091 /* 1092 * Take another reference to the SP and the SA for opencrypto callback. 1093 */ 1094 if (__predict_false(isr->sp->state == IPSEC_SPSTATE_DEAD || 1095 sav->state == SADB_SASTATE_DEAD)) { 1096 pserialize_read_exit(s); 1097 AH_STATINC(AH_STAT_NOTDB); 1098 error = ENOENT; 1099 goto bad_tc; 1100 } 1101 KEY_SP_REF(isr->sp); 1102 KEY_SA_REF(sav); 1103 pserialize_read_exit(s); 1104 } 1105 1106 /* Crypto operation descriptor. */ 1107 crp->crp_ilen = m->m_pkthdr.len; /* Total input length. */ 1108 crp->crp_flags = CRYPTO_F_IMBUF; 1109 crp->crp_buf = m; 1110 crp->crp_callback = ah_output_cb; 1111 crp->crp_sid = sav->tdb_cryptoid; 1112 crp->crp_opaque = tc; 1113 1114 /* These are passed as-is to the callback. */ 1115 tc->tc_isr = isr; 1116 tc->tc_spi = sav->spi; 1117 tc->tc_dst = sav->sah->saidx.dst; 1118 tc->tc_proto = sav->sah->saidx.proto; 1119 tc->tc_skip = skip; 1120 tc->tc_protoff = protoff; 1121 tc->tc_sav = sav; 1122 1123 return crypto_dispatch(crp); 1124 1125 bad_tc: 1126 if (__predict_true(pool_used)) 1127 pool_cache_put(ah_tdb_crypto_pool_cache, tc); 1128 else 1129 kmem_intr_free(tc, size); 1130 bad_crp: 1131 crypto_freereq(crp); 1132 bad: 1133 if (m) 1134 m_freem(m); 1135 return error; 1136 } 1137 1138 /* 1139 * AH output callback from the crypto driver. 1140 */ 1141 static int 1142 ah_output_cb(struct cryptop *crp) 1143 { 1144 int skip, error; 1145 struct tdb_crypto *tc; 1146 const struct ipsecrequest *isr; 1147 struct secasvar *sav; 1148 struct mbuf *m; 1149 void *ptr; 1150 int err; 1151 size_t size; 1152 bool pool_used; 1153 IPSEC_DECLARE_LOCK_VARIABLE; 1154 1155 KASSERT(crp->crp_opaque != NULL); 1156 tc = crp->crp_opaque; 1157 skip = tc->tc_skip; 1158 ptr = (tc + 1); 1159 m = crp->crp_buf; 1160 size = sizeof(*tc) + skip; 1161 pool_used = size <= ah_pool_item_size; 1162 1163 IPSEC_ACQUIRE_GLOBAL_LOCKS(); 1164 1165 isr = tc->tc_isr; 1166 sav = tc->tc_sav; 1167 1168 /* Check for crypto errors. */ 1169 if (crp->crp_etype) { 1170 if (sav->tdb_cryptoid != 0) 1171 sav->tdb_cryptoid = crp->crp_sid; 1172 1173 if (crp->crp_etype == EAGAIN) { 1174 IPSEC_RELEASE_GLOBAL_LOCKS(); 1175 return crypto_dispatch(crp); 1176 } 1177 1178 AH_STATINC(AH_STAT_NOXFORM); 1179 DPRINTF(("%s: crypto error %d\n", __func__, crp->crp_etype)); 1180 error = crp->crp_etype; 1181 goto bad; 1182 } 1183 1184 AH_STATINC(AH_STAT_HIST + ah_stats[sav->alg_auth]); 1185 1186 /* 1187 * Copy original headers (with the new protocol number) back 1188 * in place. 1189 */ 1190 m_copyback(m, 0, skip, ptr); 1191 1192 /* No longer needed. */ 1193 if (__predict_true(pool_used)) 1194 pool_cache_put(ah_tdb_crypto_pool_cache, tc); 1195 else 1196 kmem_intr_free(tc, size); 1197 crypto_freereq(crp); 1198 1199 #ifdef IPSEC_DEBUG 1200 /* Emulate man-in-the-middle attack when ipsec_integrity is TRUE. */ 1201 if (ipsec_integrity) { 1202 int alen; 1203 1204 /* 1205 * Corrupt HMAC if we want to test integrity verification of 1206 * the other side. 1207 */ 1208 alen = AUTHSIZE(sav); 1209 m_copyback(m, m->m_pkthdr.len - alen, alen, ipseczeroes); 1210 } 1211 #endif 1212 1213 /* NB: m is reclaimed by ipsec_process_done. */ 1214 err = ipsec_process_done(m, isr, sav); 1215 KEY_SA_UNREF(&sav); 1216 KEY_SP_UNREF(&isr->sp); 1217 IPSEC_RELEASE_GLOBAL_LOCKS(); 1218 return err; 1219 bad: 1220 if (sav) 1221 KEY_SA_UNREF(&sav); 1222 KEY_SP_UNREF(&isr->sp); 1223 IPSEC_RELEASE_GLOBAL_LOCKS(); 1224 if (m) 1225 m_freem(m); 1226 if (__predict_true(pool_used)) 1227 pool_cache_put(ah_tdb_crypto_pool_cache, tc); 1228 else 1229 kmem_intr_free(tc, size); 1230 crypto_freereq(crp); 1231 return error; 1232 } 1233 1234 static struct xformsw ah_xformsw = { 1235 .xf_type = XF_AH, 1236 .xf_flags = XFT_AUTH, 1237 .xf_name = "IPsec AH", 1238 .xf_init = ah_init, 1239 .xf_zeroize = ah_zeroize, 1240 .xf_input = ah_input, 1241 .xf_output = ah_output, 1242 .xf_next = NULL, 1243 }; 1244 1245 void 1246 ah_attach(void) 1247 { 1248 ahstat_percpu = percpu_alloc(sizeof(uint64_t) * AH_NSTATS); 1249 1250 #define MAXAUTHSIZE(name) \ 1251 if ((auth_hash_ ## name).authsize > ah_max_authsize) \ 1252 ah_max_authsize = (auth_hash_ ## name).authsize 1253 1254 ah_max_authsize = 0; 1255 MAXAUTHSIZE(null); 1256 MAXAUTHSIZE(md5); 1257 MAXAUTHSIZE(sha1); 1258 MAXAUTHSIZE(key_md5); 1259 MAXAUTHSIZE(key_sha1); 1260 MAXAUTHSIZE(hmac_md5); 1261 MAXAUTHSIZE(hmac_sha1); 1262 MAXAUTHSIZE(hmac_ripemd_160); 1263 MAXAUTHSIZE(hmac_md5_96); 1264 MAXAUTHSIZE(hmac_sha1_96); 1265 MAXAUTHSIZE(hmac_ripemd_160_96); 1266 MAXAUTHSIZE(hmac_sha2_256); 1267 MAXAUTHSIZE(hmac_sha2_384); 1268 MAXAUTHSIZE(hmac_sha2_512); 1269 MAXAUTHSIZE(aes_xcbc_mac_96); 1270 MAXAUTHSIZE(gmac_aes_128); 1271 MAXAUTHSIZE(gmac_aes_192); 1272 MAXAUTHSIZE(gmac_aes_256); 1273 IPSECLOG(LOG_DEBUG, "ah_max_authsize=%d\n", ah_max_authsize); 1274 1275 #undef MAXAUTHSIZE 1276 1277 ah_pool_item_size = sizeof(struct tdb_crypto) + 1278 sizeof(struct ip) + MAX_IPOPTLEN + 1279 sizeof(struct ah) + sizeof(uint32_t) + ah_max_authsize; 1280 ah_tdb_crypto_pool_cache = pool_cache_init(ah_pool_item_size, 1281 coherency_unit, 0, 0, "ah_tdb_crypto", NULL, IPL_SOFTNET, 1282 NULL, NULL, NULL); 1283 1284 xform_register(&ah_xformsw); 1285 } 1286