1 /* $NetBSD: xform_ah.c,v 1.115 2024/07/05 04:31:54 rin 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 (at) tla.org), 6 * Angelos D. Keromytis (kermit (at) csd.uch.gr) and 7 * Niels Provos (provos (at) 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 1.115 2024/07/05 04:31:54 rin 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 void ah_input_cb(struct cryptop *); 112 static void 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("unsupported authentication algorithm %u\n", 205 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("replay state block inconsistency, " 216 "%s algorithm %s replay state\n", 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("no authentication key for %s algorithm\n", 223 thash->name); 224 return EINVAL; 225 } 226 keylen = _KEYLEN(sav->key_auth); 227 if (keylen != thash->keysize && thash->keysize != 0) { 228 DPRINTF("invalid keylength %d, algorithm %s requires " 229 "keysize %d\n", 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 void 268 ah_zeroize(struct secasvar *sav) 269 { 270 271 if (sav->key_auth) { 272 explicit_memset(_KEYBUF(sav->key_auth), 0, 273 _KEYLEN(sav->key_auth)); 274 } 275 276 crypto_freesession(sav->tdb_cryptoid); 277 sav->tdb_cryptoid = 0; 278 sav->tdb_authalgxform = NULL; 279 sav->tdb_xform = NULL; 280 } 281 282 /* 283 * Massage IPv4/IPv6 headers for AH processing. 284 */ 285 static int 286 ah_massage_headers(struct mbuf **m0, int proto, int skip, int alg, int out) 287 { 288 struct mbuf *m = *m0; 289 unsigned char *ptr; 290 int off, optlen; 291 #ifdef INET 292 struct ip *ip; 293 #endif 294 #ifdef INET6 295 int count, ip6optlen; 296 struct ip6_ext *ip6e; 297 struct ip6_hdr ip6; 298 int alloc, nxt; 299 #endif 300 301 switch (proto) { 302 #ifdef INET 303 case AF_INET: 304 /* 305 * This is the least painful way of dealing with IPv4 header 306 * and option processing -- just make sure they're in 307 * contiguous memory. 308 */ 309 *m0 = m = m_pullup(m, skip); 310 if (m == NULL) { 311 DPRINTF("m_pullup failed\n"); 312 return ENOBUFS; 313 } 314 315 /* Fix the IP header */ 316 ip = mtod(m, struct ip *); 317 if (ip4_ah_cleartos) 318 ip->ip_tos = 0; 319 ip->ip_ttl = 0; 320 ip->ip_sum = 0; 321 ip->ip_off = htons(ntohs(ip->ip_off) & ip4_ah_offsetmask); 322 323 if (alg == CRYPTO_MD5_KPDK || alg == CRYPTO_SHA1_KPDK) 324 ip->ip_off &= htons(IP_DF); 325 else 326 ip->ip_off = 0; 327 328 ptr = mtod(m, unsigned char *); 329 330 /* IPv4 option processing */ 331 for (off = sizeof(struct ip); off < skip;) { 332 if (ptr[off] == IPOPT_EOL) { 333 break; 334 } else if (ptr[off] == IPOPT_NOP) { 335 optlen = 1; 336 } else if (off + 1 < skip) { 337 optlen = ptr[off + 1]; 338 if (optlen < 2 || off + optlen > skip) { 339 m_freem(m); 340 return EINVAL; 341 } 342 } else { 343 m_freem(m); 344 return EINVAL; 345 } 346 347 switch (ptr[off]) { 348 case IPOPT_NOP: 349 case IPOPT_SECURITY: 350 case 0x85: /* Extended security. */ 351 case 0x86: /* Commercial security. */ 352 case 0x94: /* Router alert */ 353 case 0x95: /* RFC1770 */ 354 break; 355 356 case IPOPT_LSRR: 357 case IPOPT_SSRR: 358 /* 359 * On output, if we have either of the 360 * source routing options, we should 361 * swap the destination address of the 362 * IP header with the last address 363 * specified in the option, as that is 364 * what the destination's IP header 365 * will look like. 366 */ 367 if (out) 368 memcpy(&ip->ip_dst, 369 ptr + off + optlen - 370 sizeof(struct in_addr), 371 sizeof(struct in_addr)); 372 /* FALLTHROUGH */ 373 374 default: 375 /* Zeroize all other options. */ 376 memset(ptr + off, 0, optlen); 377 break; 378 } 379 380 off += optlen; 381 382 /* Sanity check. */ 383 if (off > skip) { 384 m_freem(m); 385 return EINVAL; 386 } 387 } 388 389 break; 390 #endif /* INET */ 391 392 #ifdef INET6 393 case AF_INET6: /* Ugly... */ 394 /* Copy and "cook" the IPv6 header. */ 395 m_copydata(m, 0, sizeof(ip6), &ip6); 396 397 /* We don't do IPv6 Jumbograms. */ 398 if (ip6.ip6_plen == 0) { 399 DPRINTF("unsupported IPv6 jumbogram\n"); 400 m_freem(m); 401 return EMSGSIZE; 402 } 403 404 ip6.ip6_flow = 0; 405 ip6.ip6_hlim = 0; 406 ip6.ip6_vfc &= ~IPV6_VERSION_MASK; 407 ip6.ip6_vfc |= IPV6_VERSION; 408 409 /* Scoped address handling. */ 410 if (IN6_IS_SCOPE_LINKLOCAL(&ip6.ip6_src)) 411 ip6.ip6_src.s6_addr16[1] = 0; 412 if (IN6_IS_SCOPE_LINKLOCAL(&ip6.ip6_dst)) 413 ip6.ip6_dst.s6_addr16[1] = 0; 414 415 /* Done with IPv6 header. */ 416 m_copyback(m, 0, sizeof(struct ip6_hdr), &ip6); 417 418 ip6optlen = skip - sizeof(struct ip6_hdr); 419 420 /* Let's deal with the remaining headers (if any). */ 421 if (ip6optlen > 0) { 422 if (m->m_len <= skip) { 423 ptr = malloc(ip6optlen, M_XDATA, M_NOWAIT); 424 if (ptr == NULL) { 425 DPRINTF("failed to allocate " 426 "memory for IPv6 headers\n"); 427 m_freem(m); 428 return ENOBUFS; 429 } 430 431 /* 432 * Copy all the protocol headers after 433 * the IPv6 header. 434 */ 435 m_copydata(m, sizeof(struct ip6_hdr), 436 ip6optlen, ptr); 437 alloc = 1; 438 } else { 439 /* No need to allocate memory. */ 440 ptr = mtod(m, unsigned char *) + 441 sizeof(struct ip6_hdr); 442 alloc = 0; 443 } 444 } else 445 break; 446 447 nxt = ip6.ip6_nxt & 0xff; /* Next header type. */ 448 449 for (off = 0; off < ip6optlen;) { 450 int noff; 451 452 if (off + sizeof(*ip6e) > ip6optlen) { 453 goto error6; 454 } 455 ip6e = (struct ip6_ext *)(ptr + off); 456 noff = off + ((ip6e->ip6e_len + 1) << 3); 457 if (noff > ip6optlen) { 458 goto error6; 459 } 460 461 switch (nxt) { 462 case IPPROTO_HOPOPTS: 463 case IPPROTO_DSTOPTS: 464 /* Zero out mutable options. */ 465 for (count = off + sizeof(struct ip6_ext); 466 count < noff;) { 467 if (ptr[count] == IP6OPT_PAD1) { 468 count++; 469 continue; 470 } 471 472 if (count + 1 >= noff) { 473 goto error6; 474 } 475 optlen = ptr[count + 1] + 2; 476 477 if (count + optlen > noff) { 478 goto error6; 479 } 480 481 if (ptr[count] & IP6OPT_MUTABLE) { 482 memset(ptr + count, 0, optlen); 483 } 484 485 count += optlen; 486 } 487 if (count != noff) { 488 goto error6; 489 } 490 /* FALLTHROUGH */ 491 492 case IPPROTO_ROUTING: 493 /* Advance. */ 494 off = noff; 495 nxt = ip6e->ip6e_nxt; 496 break; 497 498 default: 499 error6: 500 if (alloc) 501 free(ptr, M_XDATA); 502 m_freem(m); 503 return EINVAL; 504 } 505 } 506 507 /* Copyback and free, if we allocated. */ 508 if (alloc) { 509 m_copyback(m, sizeof(struct ip6_hdr), ip6optlen, ptr); 510 free(ptr, M_XDATA); 511 } 512 513 break; 514 #endif /* INET6 */ 515 } 516 517 return 0; 518 } 519 520 /* 521 * ah_input() gets called to verify that an input packet 522 * passes authentication. 523 */ 524 static int 525 ah_input(struct mbuf *m, struct secasvar *sav, int skip, int protoff) 526 { 527 const struct auth_hash *ahx; 528 struct tdb_crypto *tc = NULL; 529 struct newah *ah; 530 int hl, rplen, authsize, ahsize, error, stat = AH_STAT_HDROPS; 531 struct cryptodesc *crda; 532 struct cryptop *crp = NULL; 533 bool pool_used; 534 uint8_t nxt; 535 536 KASSERT(sav != NULL); 537 KASSERT(sav->key_auth != NULL); 538 KASSERT(sav->tdb_authalgxform != NULL); 539 540 /* Figure out header size. */ 541 rplen = HDRSIZE(sav); 542 543 /* XXX don't pullup, just copy header */ 544 M_REGION_GET(ah, struct newah *, m, skip, rplen); 545 if (ah == NULL) { 546 /* m already freed */ 547 return ENOBUFS; 548 } 549 550 nxt = ah->ah_nxt; 551 552 /* Check replay window, if applicable. */ 553 if (sav->replay && !ipsec_chkreplay(ntohl(ah->ah_seq), sav)) { 554 char buf[IPSEC_LOGSASTRLEN]; 555 DPRINTF("packet replay failure: %s\n", 556 ipsec_logsastr(sav, buf, sizeof(buf))); 557 stat = AH_STAT_REPLAY; 558 error = EACCES; 559 goto bad; 560 } 561 562 /* Verify AH header length. */ 563 hl = sizeof(struct ah) + (ah->ah_len * sizeof(uint32_t)); 564 ahx = sav->tdb_authalgxform; 565 authsize = AUTHSIZE(sav); 566 ahsize = ah_hdrsiz(sav); 567 if (hl != ahsize) { 568 char buf[IPSEC_ADDRSTRLEN]; 569 DPRINTF("bad authenticator length %u (expecting %lu)" 570 " for packet in SA %s/%08lx\n", 571 hl, (u_long)ahsize, 572 ipsec_address(&sav->sah->saidx.dst, buf, sizeof(buf)), 573 (u_long) ntohl(sav->spi)); 574 stat = AH_STAT_BADAUTHL; 575 error = EACCES; 576 goto bad; 577 } 578 if (skip + ahsize > m->m_pkthdr.len) { 579 char buf[IPSEC_ADDRSTRLEN]; 580 DPRINTF("bad mbuf length %u (expecting >= %lu)" 581 " for packet in SA %s/%08lx\n", 582 m->m_pkthdr.len, (u_long)(skip + ahsize), 583 ipsec_address(&sav->sah->saidx.dst, buf, sizeof(buf)), 584 (u_long) ntohl(sav->spi)); 585 stat = AH_STAT_BADAUTHL; 586 error = EACCES; 587 goto bad; 588 } 589 590 AH_STATADD(AH_STAT_IBYTES, m->m_pkthdr.len - skip - hl); 591 592 /* Get crypto descriptors. */ 593 crp = crypto_getreq(1); 594 if (crp == NULL) { 595 DPRINTF("failed to acquire crypto descriptor\n"); 596 stat = AH_STAT_CRYPTO; 597 error = ENOBUFS; 598 goto bad; 599 } 600 601 crda = crp->crp_desc; 602 KASSERT(crda != NULL); 603 604 crda->crd_skip = 0; 605 crda->crd_len = m->m_pkthdr.len; 606 crda->crd_inject = skip + rplen; 607 608 /* Authentication operation. */ 609 crda->crd_alg = ahx->type; 610 crda->crd_key = _KEYBUF(sav->key_auth); 611 crda->crd_klen = _KEYBITS(sav->key_auth); 612 613 /* Allocate IPsec-specific opaque crypto info. */ 614 size_t size = sizeof(*tc); 615 size_t extra = skip + rplen + authsize; 616 size += extra; 617 618 if (__predict_true(size <= ah_pool_item_size)) { 619 tc = pool_cache_get(ah_tdb_crypto_pool_cache, PR_NOWAIT); 620 pool_used = true; 621 } else { 622 /* size can exceed on IPv6 packets with large options. */ 623 tc = kmem_intr_zalloc(size, KM_NOSLEEP); 624 pool_used = false; 625 } 626 if (tc == NULL) { 627 DPRINTF("failed to allocate tdb_crypto\n"); 628 stat = AH_STAT_CRYPTO; 629 error = ENOBUFS; 630 goto bad; 631 } 632 633 error = m_makewritable(&m, 0, extra, M_NOWAIT); 634 if (error) { 635 DPRINTF("failed to m_makewritable\n"); 636 goto bad; 637 } 638 639 /* 640 * Save the authenticator, the skipped portion of the packet, 641 * and the AH header. 642 */ 643 m_copydata(m, 0, extra, (tc + 1)); 644 /* Zeroize the authenticator on the packet. */ 645 m_copyback(m, skip + rplen, authsize, ipseczeroes); 646 647 /* "Massage" the packet headers for crypto processing. */ 648 error = ah_massage_headers(&m, sav->sah->saidx.dst.sa.sa_family, 649 skip, ahx->type, 0); 650 if (error != 0) { 651 /* NB: mbuf is free'd by ah_massage_headers */ 652 m = NULL; 653 goto bad; 654 } 655 656 { 657 int s = pserialize_read_enter(); 658 659 /* 660 * Take another reference to the SA for opencrypto callback. 661 */ 662 if (__predict_false(sav->state == SADB_SASTATE_DEAD)) { 663 pserialize_read_exit(s); 664 stat = AH_STAT_NOTDB; 665 error = ENOENT; 666 goto bad; 667 } 668 KEY_SA_REF(sav); 669 pserialize_read_exit(s); 670 } 671 672 /* Crypto operation descriptor. */ 673 crp->crp_ilen = m->m_pkthdr.len; /* Total input length. */ 674 crp->crp_flags = CRYPTO_F_IMBUF; 675 crp->crp_buf = m; 676 crp->crp_callback = ah_input_cb; 677 crp->crp_sid = sav->tdb_cryptoid; 678 crp->crp_opaque = tc; 679 680 /* These are passed as-is to the callback. */ 681 tc->tc_spi = sav->spi; 682 tc->tc_dst = sav->sah->saidx.dst; 683 tc->tc_proto = sav->sah->saidx.proto; 684 tc->tc_nxt = nxt; 685 tc->tc_protoff = protoff; 686 tc->tc_skip = skip; 687 tc->tc_sav = sav; 688 689 DPRINTF("hash over %d bytes, skip %d: " 690 "crda len %d skip %d inject %d\n", 691 crp->crp_ilen, tc->tc_skip, 692 crda->crd_len, crda->crd_skip, crda->crd_inject); 693 694 crypto_dispatch(crp); 695 return 0; 696 697 bad: 698 if (tc != NULL) { 699 if (__predict_true(pool_used)) 700 pool_cache_put(ah_tdb_crypto_pool_cache, tc); 701 else 702 kmem_intr_free(tc, size); 703 } 704 if (crp != NULL) 705 crypto_freereq(crp); 706 m_freem(m); 707 AH_STATINC(stat); 708 return error; 709 } 710 711 #ifdef INET6 712 #define IPSEC_COMMON_INPUT_CB(m, sav, skip, protoff) do { \ 713 if (saidx->dst.sa.sa_family == AF_INET6) { \ 714 (void)ipsec6_common_input_cb(m, sav, skip, protoff); \ 715 } else { \ 716 (void)ipsec4_common_input_cb(m, sav, skip, protoff); \ 717 } \ 718 } while (0) 719 #else 720 #define IPSEC_COMMON_INPUT_CB(m, sav, skip, protoff) \ 721 ((void)ipsec4_common_input_cb(m, sav, skip, protoff)) 722 #endif 723 724 /* 725 * AH input callback from the crypto driver. 726 */ 727 static void 728 ah_input_cb(struct cryptop *crp) 729 { 730 char buf[IPSEC_ADDRSTRLEN]; 731 int rplen, ahsize, skip, protoff; 732 unsigned char calc[AH_ALEN_MAX]; 733 struct mbuf *m; 734 struct tdb_crypto *tc; 735 struct secasvar *sav; 736 struct secasindex *saidx; 737 uint8_t nxt; 738 char *ptr; 739 int authsize; 740 bool pool_used; 741 size_t size; 742 IPSEC_DECLARE_LOCK_VARIABLE; 743 744 KASSERT(crp->crp_opaque != NULL); 745 tc = crp->crp_opaque; 746 skip = tc->tc_skip; 747 nxt = tc->tc_nxt; 748 protoff = tc->tc_protoff; 749 m = crp->crp_buf; 750 751 IPSEC_ACQUIRE_GLOBAL_LOCKS(); 752 753 sav = tc->tc_sav; 754 saidx = &sav->sah->saidx; 755 KASSERTMSG(saidx->dst.sa.sa_family == AF_INET || 756 saidx->dst.sa.sa_family == AF_INET6, 757 "unexpected protocol family %u", saidx->dst.sa.sa_family); 758 759 /* Figure out header size. */ 760 rplen = HDRSIZE(sav); 761 authsize = AUTHSIZE(sav); 762 ahsize = ah_hdrsiz(sav); 763 764 size = sizeof(*tc) + skip + rplen + authsize; 765 if (__predict_true(size <= ah_pool_item_size)) 766 pool_used = true; 767 else 768 pool_used = false; 769 770 /* Check for crypto errors. */ 771 if (crp->crp_etype) { 772 if (sav->tdb_cryptoid != 0) 773 sav->tdb_cryptoid = crp->crp_sid; 774 775 AH_STATINC(AH_STAT_NOXFORM); 776 DPRINTF("crypto error %d\n", crp->crp_etype); 777 goto bad; 778 } else { 779 AH_STATINC(AH_STAT_HIST + ah_stats[sav->alg_auth]); 780 crypto_freereq(crp); /* No longer needed. */ 781 crp = NULL; 782 } 783 784 if (ipsec_debug) 785 memset(calc, 0, sizeof(calc)); 786 787 /* Copy authenticator off the packet. */ 788 m_copydata(m, skip + rplen, authsize, calc); 789 790 ptr = (char *)(tc + 1); 791 const uint8_t *pppp = ptr + skip + rplen; 792 793 /* Verify authenticator. */ 794 if (!consttime_memequal(pppp, calc, authsize)) { 795 DPRINTF("authentication hash mismatch " \ 796 "over %d bytes " \ 797 "for packet in SA %s/%08lx:\n" \ 798 "%02x%02x:%02x%02x:%02x%02x:%02x%02x:%02x%02x:%02x%02x, " \ 799 "%02x%02x:%02x%02x:%02x%02x:%02x%02x:%02x%02x:%02x%02x\n", 800 authsize, ipsec_address(&saidx->dst, buf, sizeof(buf)), 801 (u_long) ntohl(sav->spi), 802 calc[0], calc[1], calc[2], calc[3], 803 calc[4], calc[5], calc[6], calc[7], 804 calc[8], calc[9], calc[10], calc[11], 805 pppp[0], pppp[1], pppp[2], pppp[3], 806 pppp[4], pppp[5], pppp[6], pppp[7], 807 pppp[8], pppp[9], pppp[10], pppp[11]); 808 AH_STATINC(AH_STAT_BADAUTH); 809 goto bad; 810 } 811 812 /* Fix the Next Protocol field. */ 813 ptr[protoff] = nxt; 814 815 /* Copyback the saved (uncooked) network headers. */ 816 m_copyback(m, 0, skip, ptr); 817 818 if (__predict_true(pool_used)) 819 pool_cache_put(ah_tdb_crypto_pool_cache, tc); 820 else 821 kmem_intr_free(tc, size); 822 tc = NULL; 823 824 /* 825 * Header is now authenticated. 826 */ 827 m->m_flags |= M_AUTHIPHDR; 828 829 /* 830 * Update replay sequence number, if appropriate. 831 */ 832 if (sav->replay) { 833 uint32_t seq; 834 835 m_copydata(m, skip + offsetof(struct newah, ah_seq), 836 sizeof(seq), &seq); 837 if (ipsec_updatereplay(ntohl(seq), sav)) { 838 AH_STATINC(AH_STAT_REPLAY); 839 goto bad; 840 } 841 } 842 843 /* 844 * Remove the AH header and authenticator from the mbuf. 845 */ 846 if (m_striphdr(m, skip, ahsize) != 0) { 847 DPRINTF("mangled mbuf chain for SA %s/%08lx\n", 848 ipsec_address(&saidx->dst, buf, sizeof(buf)), 849 (u_long) ntohl(sav->spi)); 850 851 AH_STATINC(AH_STAT_HDROPS); 852 goto bad; 853 } 854 855 IPSEC_COMMON_INPUT_CB(m, sav, skip, protoff); 856 857 KEY_SA_UNREF(&sav); 858 IPSEC_RELEASE_GLOBAL_LOCKS(); 859 return; 860 861 bad: 862 if (sav) 863 KEY_SA_UNREF(&sav); 864 IPSEC_RELEASE_GLOBAL_LOCKS(); 865 m_freem(m); 866 if (tc != NULL) { 867 if (pool_used) 868 pool_cache_put(ah_tdb_crypto_pool_cache, tc); 869 else 870 kmem_intr_free(tc, size); 871 } 872 if (crp != NULL) 873 crypto_freereq(crp); 874 return; 875 } 876 877 /* 878 * AH output routine, called by ipsec[46]_process_packet(). 879 */ 880 static int 881 ah_output(struct mbuf *m, const struct ipsecrequest *isr, struct secasvar *sav, 882 int skip, int protoff, int flags) 883 { 884 char buf[IPSEC_ADDRSTRLEN]; 885 const struct auth_hash *ahx; 886 struct cryptodesc *crda; 887 struct tdb_crypto *tc; 888 struct mbuf *mi; 889 struct cryptop *crp; 890 uint16_t iplen; 891 int error, rplen, authsize, ahsize, maxpacketsize, roff; 892 uint8_t prot; 893 struct newah *ah; 894 size_t ipoffs; 895 bool pool_used; 896 897 KASSERT(sav != NULL); 898 KASSERT(sav->tdb_authalgxform != NULL); 899 ahx = sav->tdb_authalgxform; 900 901 AH_STATINC(AH_STAT_OUTPUT); 902 903 /* Figure out header size. */ 904 rplen = HDRSIZE(sav); 905 authsize = AUTHSIZE(sav); 906 ahsize = ah_hdrsiz(sav); 907 908 /* Check for maximum packet size violations. */ 909 switch (sav->sah->saidx.dst.sa.sa_family) { 910 #ifdef INET 911 case AF_INET: 912 maxpacketsize = IP_MAXPACKET; 913 ipoffs = offsetof(struct ip, ip_len); 914 break; 915 #endif 916 #ifdef INET6 917 case AF_INET6: 918 maxpacketsize = IPV6_MAXPACKET; 919 ipoffs = offsetof(struct ip6_hdr, ip6_plen); 920 break; 921 #endif 922 default: 923 DPRINTF("unknown/unsupported protocol " 924 "family %u, SA %s/%08lx\n", 925 sav->sah->saidx.dst.sa.sa_family, 926 ipsec_address(&sav->sah->saidx.dst, buf, sizeof(buf)), 927 (u_long) ntohl(sav->spi)); 928 AH_STATINC(AH_STAT_NOPF); 929 error = EPFNOSUPPORT; 930 goto bad; 931 } 932 if (ahsize + m->m_pkthdr.len > maxpacketsize) { 933 DPRINTF("packet in SA %s/%08lx got too big " 934 "(len %u, max len %u)\n", 935 ipsec_address(&sav->sah->saidx.dst, buf, sizeof(buf)), 936 (u_long) ntohl(sav->spi), 937 ahsize + m->m_pkthdr.len, maxpacketsize); 938 AH_STATINC(AH_STAT_TOOBIG); 939 error = EMSGSIZE; 940 goto bad; 941 } 942 943 /* Update the counters. */ 944 AH_STATADD(AH_STAT_OBYTES, m->m_pkthdr.len - skip); 945 946 m = m_clone(m); 947 if (m == NULL) { 948 DPRINTF("cannot clone mbuf chain, SA %s/%08lx\n", 949 ipsec_address(&sav->sah->saidx.dst, buf, sizeof(buf)), 950 (u_long) ntohl(sav->spi)); 951 AH_STATINC(AH_STAT_HDROPS); 952 error = ENOBUFS; 953 goto bad; 954 } 955 956 /* Inject AH header. */ 957 mi = m_makespace(m, skip, ahsize, &roff); 958 if (mi == NULL) { 959 DPRINTF("failed to inject %u byte AH header for SA " 960 "%s/%08lx\n", ahsize, 961 ipsec_address(&sav->sah->saidx.dst, buf, sizeof(buf)), 962 (u_long) ntohl(sav->spi)); 963 AH_STATINC(AH_STAT_HDROPS); 964 error = ENOBUFS; 965 goto bad; 966 } 967 968 /* 969 * The AH header is guaranteed by m_makespace() to be in 970 * contiguous memory, at roff bytes offset into the returned mbuf. 971 */ 972 ah = (struct newah *)(mtod(mi, char *) + roff); 973 974 /* Initialize the AH header. */ 975 m_copydata(m, protoff, sizeof(uint8_t), &ah->ah_nxt); 976 ah->ah_len = (ahsize - sizeof(struct ah)) / sizeof(uint32_t); 977 ah->ah_reserve = 0; 978 ah->ah_spi = sav->spi; 979 980 /* Zeroize authenticator. */ 981 m_copyback(m, skip + rplen, authsize, ipseczeroes); 982 983 /* Zeroize padding. */ 984 m_copyback(m, skip + rplen + authsize, ahsize - (rplen + authsize), 985 ipseczeroes); 986 987 /* Insert packet replay counter, as requested. */ 988 if (sav->replay) { 989 if (sav->replay->count == ~0 && 990 (sav->flags & SADB_X_EXT_CYCSEQ) == 0) { 991 DPRINTF("replay counter wrapped for SA %s/%08lx\n", 992 ipsec_address(&sav->sah->saidx.dst, buf, 993 sizeof(buf)), (u_long) ntohl(sav->spi)); 994 AH_STATINC(AH_STAT_WRAP); 995 error = EINVAL; 996 goto bad; 997 } 998 #ifdef IPSEC_DEBUG 999 /* Emulate replay attack when ipsec_replay is TRUE. */ 1000 if (!ipsec_replay) 1001 #endif 1002 sav->replay->count++; 1003 ah->ah_seq = htonl(sav->replay->count); 1004 } 1005 1006 /* Get crypto descriptors. */ 1007 crp = crypto_getreq(1); 1008 if (crp == NULL) { 1009 DPRINTF("failed to acquire crypto descriptors\n"); 1010 AH_STATINC(AH_STAT_CRYPTO); 1011 error = ENOBUFS; 1012 goto bad; 1013 } 1014 1015 crda = crp->crp_desc; 1016 1017 crda->crd_skip = 0; 1018 crda->crd_inject = skip + rplen; 1019 crda->crd_len = m->m_pkthdr.len; 1020 1021 /* Authentication operation. */ 1022 crda->crd_alg = ahx->type; 1023 crda->crd_key = _KEYBUF(sav->key_auth); 1024 crda->crd_klen = _KEYBITS(sav->key_auth); 1025 1026 /* Allocate IPsec-specific opaque crypto info. */ 1027 size_t size = sizeof(*tc) + skip; 1028 1029 if (__predict_true(size <= ah_pool_item_size)) { 1030 tc = pool_cache_get(ah_tdb_crypto_pool_cache, PR_NOWAIT); 1031 pool_used = true; 1032 } else { 1033 /* size can exceed on IPv6 packets with large options. */ 1034 tc = kmem_intr_zalloc(size, KM_NOSLEEP); 1035 pool_used = false; 1036 } 1037 if (tc == NULL) { 1038 DPRINTF("failed to allocate tdb_crypto\n"); 1039 AH_STATINC(AH_STAT_CRYPTO); 1040 error = ENOBUFS; 1041 goto bad_crp; 1042 } 1043 1044 uint8_t *pext = (char *)(tc + 1); 1045 /* Save the skipped portion of the packet. */ 1046 m_copydata(m, 0, skip, pext); 1047 1048 /* 1049 * Fix IP header length on the header used for 1050 * authentication. We don't need to fix the original 1051 * header length as it will be fixed by our caller. 1052 */ 1053 memcpy(&iplen, pext + ipoffs, sizeof(iplen)); 1054 iplen = htons(ntohs(iplen) + ahsize); 1055 m_copyback(m, ipoffs, sizeof(iplen), &iplen); 1056 1057 /* Fix the Next Header field in saved header. */ 1058 pext[protoff] = IPPROTO_AH; 1059 1060 /* Update the Next Protocol field in the IP header. */ 1061 prot = IPPROTO_AH; 1062 m_copyback(m, protoff, sizeof(prot), &prot); 1063 1064 /* "Massage" the packet headers for crypto processing. */ 1065 error = ah_massage_headers(&m, sav->sah->saidx.dst.sa.sa_family, 1066 skip, ahx->type, 1); 1067 if (error != 0) { 1068 m = NULL; /* mbuf was free'd by ah_massage_headers. */ 1069 goto bad_tc; 1070 } 1071 1072 { 1073 int s = pserialize_read_enter(); 1074 1075 /* 1076 * Take another reference to the SP and the SA for opencrypto callback. 1077 */ 1078 if (__predict_false(isr->sp->state == IPSEC_SPSTATE_DEAD || 1079 sav->state == SADB_SASTATE_DEAD)) { 1080 pserialize_read_exit(s); 1081 AH_STATINC(AH_STAT_NOTDB); 1082 error = ENOENT; 1083 goto bad_tc; 1084 } 1085 KEY_SP_REF(isr->sp); 1086 KEY_SA_REF(sav); 1087 pserialize_read_exit(s); 1088 } 1089 1090 /* Crypto operation descriptor. */ 1091 crp->crp_ilen = m->m_pkthdr.len; /* Total input length. */ 1092 crp->crp_flags = CRYPTO_F_IMBUF; 1093 crp->crp_buf = m; 1094 crp->crp_callback = ah_output_cb; 1095 crp->crp_sid = sav->tdb_cryptoid; 1096 crp->crp_opaque = tc; 1097 1098 /* These are passed as-is to the callback. */ 1099 tc->tc_isr = isr; 1100 tc->tc_spi = sav->spi; 1101 tc->tc_dst = sav->sah->saidx.dst; 1102 tc->tc_proto = sav->sah->saidx.proto; 1103 tc->tc_skip = skip; 1104 tc->tc_protoff = protoff; 1105 tc->tc_flags = flags; 1106 tc->tc_sav = sav; 1107 1108 crypto_dispatch(crp); 1109 return 0; 1110 1111 bad_tc: 1112 if (__predict_true(pool_used)) 1113 pool_cache_put(ah_tdb_crypto_pool_cache, tc); 1114 else 1115 kmem_intr_free(tc, size); 1116 bad_crp: 1117 crypto_freereq(crp); 1118 bad: 1119 m_freem(m); 1120 return error; 1121 } 1122 1123 /* 1124 * AH output callback from the crypto driver. 1125 */ 1126 static void 1127 ah_output_cb(struct cryptop *crp) 1128 { 1129 int skip; 1130 struct tdb_crypto *tc; 1131 const struct ipsecrequest *isr; 1132 struct secasvar *sav; 1133 struct mbuf *m; 1134 void *ptr; 1135 int flags; 1136 size_t size; 1137 bool pool_used; 1138 IPSEC_DECLARE_LOCK_VARIABLE; 1139 1140 KASSERT(crp->crp_opaque != NULL); 1141 tc = crp->crp_opaque; 1142 skip = tc->tc_skip; 1143 ptr = (tc + 1); 1144 m = crp->crp_buf; 1145 size = sizeof(*tc) + skip; 1146 pool_used = size <= ah_pool_item_size; 1147 1148 IPSEC_ACQUIRE_GLOBAL_LOCKS(); 1149 1150 isr = tc->tc_isr; 1151 sav = tc->tc_sav; 1152 1153 /* Check for crypto errors. */ 1154 if (crp->crp_etype) { 1155 if (sav->tdb_cryptoid != 0) 1156 sav->tdb_cryptoid = crp->crp_sid; 1157 1158 AH_STATINC(AH_STAT_NOXFORM); 1159 DPRINTF("crypto error %d\n", crp->crp_etype); 1160 goto bad; 1161 } 1162 1163 AH_STATINC(AH_STAT_HIST + ah_stats[sav->alg_auth]); 1164 1165 /* 1166 * Copy original headers (with the new protocol number) back 1167 * in place. 1168 */ 1169 m_copyback(m, 0, skip, ptr); 1170 1171 flags = tc->tc_flags; 1172 /* No longer needed. */ 1173 if (__predict_true(pool_used)) 1174 pool_cache_put(ah_tdb_crypto_pool_cache, tc); 1175 else 1176 kmem_intr_free(tc, size); 1177 crypto_freereq(crp); 1178 1179 #ifdef IPSEC_DEBUG 1180 /* Emulate man-in-the-middle attack when ipsec_integrity is TRUE. */ 1181 if (ipsec_integrity) { 1182 int alen; 1183 1184 /* 1185 * Corrupt HMAC if we want to test integrity verification of 1186 * the other side. 1187 */ 1188 alen = AUTHSIZE(sav); 1189 m_copyback(m, m->m_pkthdr.len - alen, alen, ipseczeroes); 1190 } 1191 #endif 1192 1193 /* NB: m is reclaimed by ipsec_process_done. */ 1194 (void)ipsec_process_done(m, isr, sav, flags); 1195 KEY_SA_UNREF(&sav); 1196 KEY_SP_UNREF(&isr->sp); 1197 IPSEC_RELEASE_GLOBAL_LOCKS(); 1198 return; 1199 bad: 1200 if (sav) 1201 KEY_SA_UNREF(&sav); 1202 KEY_SP_UNREF(&isr->sp); 1203 IPSEC_RELEASE_GLOBAL_LOCKS(); 1204 m_freem(m); 1205 if (__predict_true(pool_used)) 1206 pool_cache_put(ah_tdb_crypto_pool_cache, tc); 1207 else 1208 kmem_intr_free(tc, size); 1209 crypto_freereq(crp); 1210 } 1211 1212 static struct xformsw ah_xformsw = { 1213 .xf_type = XF_AH, 1214 .xf_flags = XFT_AUTH, 1215 .xf_name = "IPsec AH", 1216 .xf_init = ah_init, 1217 .xf_zeroize = ah_zeroize, 1218 .xf_input = ah_input, 1219 .xf_output = ah_output, 1220 .xf_next = NULL, 1221 }; 1222 1223 void 1224 ah_attach(void) 1225 { 1226 ahstat_percpu = percpu_alloc(sizeof(uint64_t) * AH_NSTATS); 1227 1228 #define MAXAUTHSIZE(name) \ 1229 if ((auth_hash_ ## name).authsize > ah_max_authsize) \ 1230 ah_max_authsize = (auth_hash_ ## name).authsize 1231 1232 ah_max_authsize = 0; 1233 MAXAUTHSIZE(null); 1234 MAXAUTHSIZE(md5); 1235 MAXAUTHSIZE(sha1); 1236 MAXAUTHSIZE(key_md5); 1237 MAXAUTHSIZE(key_sha1); 1238 MAXAUTHSIZE(hmac_md5); 1239 MAXAUTHSIZE(hmac_sha1); 1240 MAXAUTHSIZE(hmac_ripemd_160); 1241 MAXAUTHSIZE(hmac_md5_96); 1242 MAXAUTHSIZE(hmac_sha1_96); 1243 MAXAUTHSIZE(hmac_ripemd_160_96); 1244 MAXAUTHSIZE(hmac_sha2_256); 1245 MAXAUTHSIZE(hmac_sha2_384); 1246 MAXAUTHSIZE(hmac_sha2_512); 1247 MAXAUTHSIZE(aes_xcbc_mac_96); 1248 MAXAUTHSIZE(gmac_aes_128); 1249 MAXAUTHSIZE(gmac_aes_192); 1250 MAXAUTHSIZE(gmac_aes_256); 1251 IPSECLOG(LOG_DEBUG, "ah_max_authsize=%d\n", ah_max_authsize); 1252 1253 #undef MAXAUTHSIZE 1254 1255 ah_pool_item_size = sizeof(struct tdb_crypto) + 1256 sizeof(struct ip) + MAX_IPOPTLEN + 1257 sizeof(struct ah) + sizeof(uint32_t) + ah_max_authsize; 1258 ah_tdb_crypto_pool_cache = pool_cache_init(ah_pool_item_size, 1259 coherency_unit, 0, 0, "ah_tdb_crypto", NULL, IPL_SOFTNET, 1260 NULL, NULL, NULL); 1261 1262 xform_register(&ah_xformsw); 1263 } 1264
Indexes created Sat Sep 20 22:09:52 GMT 2025