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 42 #include <sys/param.h> 43 #include <sys/systm.h> 44 #include <sys/mbuf.h> 45 #include <sys/socket.h> 46 #include <sys/syslog.h> 47 #include <sys/kernel.h> 48 #include <sys/lock.h> 49 #include <sys/mutex.h> 50 #include <sys/sysctl.h> 51 52 #include <net/if.h> 53 #include <net/vnet.h> 54 55 #include <netinet/in.h> 56 #include <netinet/in_systm.h> 57 #include <netinet/ip.h> 58 #include <netinet/ip_ecn.h> 59 #include <netinet/ip6.h> 60 61 #include <netipsec/ipsec.h> 62 #include <netipsec/ah.h> 63 #include <netipsec/ah_var.h> 64 #include <netipsec/xform.h> 65 66 #ifdef INET6 67 #include <netinet6/ip6_var.h> 68 #include <netipsec/ipsec6.h> 69 #include <netinet6/ip6_ecn.h> 70 #endif 71 72 #include <netipsec/key.h> 73 #include <netipsec/key_debug.h> 74 75 #include <opencrypto/cryptodev.h> 76 77 /* 78 * Return header size in bytes. The old protocol did not support 79 * the replay counter; the new protocol always includes the counter. 80 */ 81 #define HDRSIZE(sav) \ 82 (((sav)->flags & SADB_X_EXT_OLD) ? \ 83 sizeof (struct ah) : sizeof (struct ah) + sizeof (u_int32_t)) 84 /* 85 * Return authenticator size in bytes, based on a field in the 86 * algorithm descriptor. 87 */ 88 #define AUTHSIZE(sav) ((sav->flags & SADB_X_EXT_OLD) ? 16 : \ 89 xform_ah_authsize((sav)->tdb_authalgxform)) 90 91 VNET_DEFINE(int, ah_enable) = 1; /* control flow of packets with AH */ 92 VNET_DEFINE(int, ah_cleartos) = 1; /* clear ip_tos when doing AH calc */ 93 VNET_PCPUSTAT_DEFINE(struct ahstat, ahstat); 94 VNET_PCPUSTAT_SYSINIT(ahstat); 95 96 #ifdef VIMAGE 97 VNET_PCPUSTAT_SYSUNINIT(ahstat); 98 #endif /* VIMAGE */ 99 100 #ifdef INET 101 SYSCTL_DECL(_net_inet_ah); 102 SYSCTL_INT(_net_inet_ah, OID_AUTO, ah_enable, 103 CTLFLAG_VNET | CTLFLAG_RW, &VNET_NAME(ah_enable), 0, ""); 104 SYSCTL_INT(_net_inet_ah, OID_AUTO, ah_cleartos, 105 CTLFLAG_VNET | CTLFLAG_RW, &VNET_NAME(ah_cleartos), 0, ""); 106 SYSCTL_VNET_PCPUSTAT(_net_inet_ah, IPSECCTL_STATS, stats, struct ahstat, 107 ahstat, "AH statistics (struct ahstat, netipsec/ah_var.h)"); 108 #endif 109 110 static unsigned char ipseczeroes[256]; /* larger than an ip6 extension hdr */ 111 112 static int ah_input_cb(struct cryptop*); 113 static int ah_output_cb(struct cryptop*); 114 115 int 116 xform_ah_authsize(const struct auth_hash *esph) 117 { 118 int alen; 119 120 if (esph == NULL) 121 return 0; 122 123 switch (esph->type) { 124 case CRYPTO_SHA2_256_HMAC: 125 case CRYPTO_SHA2_384_HMAC: 126 case CRYPTO_SHA2_512_HMAC: 127 alen = esph->hashsize / 2; /* RFC4868 2.3 */ 128 break; 129 130 case CRYPTO_AES_128_NIST_GMAC: 131 case CRYPTO_AES_192_NIST_GMAC: 132 case CRYPTO_AES_256_NIST_GMAC: 133 alen = esph->hashsize; 134 break; 135 136 default: 137 alen = AH_HMAC_HASHLEN; 138 break; 139 } 140 141 return alen; 142 } 143 144 size_t 145 ah_hdrsiz(struct secasvar *sav) 146 { 147 size_t size; 148 149 if (sav != NULL) { 150 int authsize, rplen, align; 151 152 IPSEC_ASSERT(sav->tdb_authalgxform != NULL, ("null xform")); 153 /*XXX not right for null algorithm--does it matter??*/ 154 155 /* RFC4302: use the correct alignment. */ 156 align = sizeof(uint32_t); 157 #ifdef INET6 158 if (sav->sah->saidx.dst.sa.sa_family == AF_INET6) { 159 align = sizeof(uint64_t); 160 } 161 #endif 162 rplen = HDRSIZE(sav); 163 authsize = AUTHSIZE(sav); 164 size = roundup(rplen + authsize, align); 165 } else { 166 /* default guess */ 167 size = sizeof (struct ah) + sizeof (u_int32_t) + 16; 168 } 169 return size; 170 } 171 172 /* 173 * NB: public for use by esp_init. 174 */ 175 int 176 ah_init0(struct secasvar *sav, struct xformsw *xsp, struct cryptoini *cria) 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 * Verify the replay state block allocation is consistent with 189 * the protocol type. We check here so we can make assumptions 190 * later during protocol processing. 191 */ 192 /* NB: replay state is setup elsewhere (sigh) */ 193 if (((sav->flags&SADB_X_EXT_OLD) == 0) ^ (sav->replay != NULL)) { 194 DPRINTF(("%s: replay state block inconsistency, " 195 "%s algorithm %s replay state\n", __func__, 196 (sav->flags & SADB_X_EXT_OLD) ? "old" : "new", 197 sav->replay == NULL ? "without" : "with")); 198 return EINVAL; 199 } 200 if (sav->key_auth == NULL) { 201 DPRINTF(("%s: no authentication key for %s algorithm\n", 202 __func__, thash->name)); 203 return EINVAL; 204 } 205 keylen = _KEYLEN(sav->key_auth); 206 if (keylen > thash->keysize && thash->keysize != 0) { 207 DPRINTF(("%s: invalid keylength %d, algorithm %s requires " 208 "keysize less than %d\n", __func__, 209 keylen, thash->name, thash->keysize)); 210 return EINVAL; 211 } 212 213 sav->tdb_xform = xsp; 214 sav->tdb_authalgxform = thash; 215 216 /* Initialize crypto session. */ 217 bzero(cria, sizeof (*cria)); 218 cria->cri_alg = sav->tdb_authalgxform->type; 219 cria->cri_klen = _KEYBITS(sav->key_auth); 220 cria->cri_key = sav->key_auth->key_data; 221 cria->cri_mlen = AUTHSIZE(sav); 222 223 return 0; 224 } 225 226 /* 227 * ah_init() is called when an SPI is being set up. 228 */ 229 static int 230 ah_init(struct secasvar *sav, struct xformsw *xsp) 231 { 232 struct cryptoini cria; 233 int error; 234 235 error = ah_init0(sav, xsp, &cria); 236 return error ? error : 237 crypto_newsession(&sav->tdb_cryptoid, &cria, V_crypto_support); 238 } 239 240 /* 241 * Paranoia. 242 * 243 * NB: public for use by esp_zeroize (XXX). 244 */ 245 int 246 ah_zeroize(struct secasvar *sav) 247 { 248 int err; 249 250 if (sav->key_auth) 251 bzero(sav->key_auth->key_data, _KEYLEN(sav->key_auth)); 252 253 err = crypto_freesession(sav->tdb_cryptoid); 254 sav->tdb_cryptoid = 0; 255 sav->tdb_authalgxform = NULL; 256 sav->tdb_xform = NULL; 257 return err; 258 } 259 260 /* 261 * Massage IPv4/IPv6 headers for AH processing. 262 */ 263 static int 264 ah_massage_headers(struct mbuf **m0, int proto, int skip, int alg, int out) 265 { 266 struct mbuf *m = *m0; 267 unsigned char *ptr; 268 int off, count; 269 270 #ifdef INET 271 struct ip *ip; 272 #endif /* INET */ 273 274 #ifdef INET6 275 struct ip6_ext *ip6e; 276 struct ip6_hdr ip6; 277 int ad, alloc, nxt, noff; 278 #endif /* INET6 */ 279 280 switch (proto) { 281 #ifdef INET 282 case AF_INET: 283 /* 284 * This is the least painful way of dealing with IPv4 header 285 * and option processing -- just make sure they're in 286 * contiguous memory. 287 */ 288 *m0 = m = m_pullup(m, skip); 289 if (m == NULL) { 290 DPRINTF(("%s: m_pullup failed\n", __func__)); 291 return ENOBUFS; 292 } 293 294 /* Fix the IP header */ 295 ip = mtod(m, struct ip *); 296 if (V_ah_cleartos) 297 ip->ip_tos = 0; 298 ip->ip_ttl = 0; 299 ip->ip_sum = 0; 300 301 if (alg == CRYPTO_MD5_KPDK || alg == CRYPTO_SHA1_KPDK) 302 ip->ip_off &= htons(IP_DF); 303 else 304 ip->ip_off = htons(0); 305 306 ptr = mtod(m, unsigned char *); 307 308 /* IPv4 option processing */ 309 for (off = sizeof(struct ip); off < skip;) { 310 if (ptr[off] == IPOPT_EOL || ptr[off] == IPOPT_NOP || 311 off + 1 < skip) 312 ; 313 else { 314 DPRINTF(("%s: illegal IPv4 option length for " 315 "option %d\n", __func__, ptr[off])); 316 317 m_freem(m); 318 return EINVAL; 319 } 320 321 switch (ptr[off]) { 322 case IPOPT_EOL: 323 off = skip; /* End the loop. */ 324 break; 325 326 case IPOPT_NOP: 327 off++; 328 break; 329 330 case IPOPT_SECURITY: /* 0x82 */ 331 case 0x85: /* Extended security. */ 332 case 0x86: /* Commercial security. */ 333 case 0x94: /* Router alert */ 334 case 0x95: /* RFC1770 */ 335 /* Sanity check for option length. */ 336 if (ptr[off + 1] < 2) { 337 DPRINTF(("%s: illegal IPv4 option " 338 "length for option %d\n", 339 __func__, ptr[off])); 340 341 m_freem(m); 342 return EINVAL; 343 } 344 345 off += ptr[off + 1]; 346 break; 347 348 case IPOPT_LSRR: 349 case IPOPT_SSRR: 350 /* Sanity check for option length. */ 351 if (ptr[off + 1] < 2) { 352 DPRINTF(("%s: illegal IPv4 option " 353 "length for option %d\n", 354 __func__, ptr[off])); 355 356 m_freem(m); 357 return EINVAL; 358 } 359 360 /* 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 bcopy(ptr + off + ptr[off + 1] - 371 sizeof(struct in_addr), 372 &(ip->ip_dst), sizeof(struct in_addr)); 373 374 /* Fall through */ 375 default: 376 /* Sanity check for option length. */ 377 if (ptr[off + 1] < 2) { 378 DPRINTF(("%s: illegal IPv4 option " 379 "length for option %d\n", 380 __func__, ptr[off])); 381 m_freem(m); 382 return EINVAL; 383 } 384 385 /* Zeroize all other options. */ 386 count = ptr[off + 1]; 387 bcopy(ipseczeroes, ptr + off, count); 388 off += count; 389 break; 390 } 391 392 /* Sanity check. */ 393 if (off > skip) { 394 DPRINTF(("%s: malformed IPv4 options header\n", 395 __func__)); 396 397 m_freem(m); 398 return EINVAL; 399 } 400 } 401 402 break; 403 #endif /* INET */ 404 405 #ifdef INET6 406 case AF_INET6: /* Ugly... */ 407 /* Copy and "cook" the IPv6 header. */ 408 m_copydata(m, 0, sizeof(ip6), (caddr_t) &ip6); 409 410 /* We don't do IPv6 Jumbograms. */ 411 if (ip6.ip6_plen == 0) { 412 DPRINTF(("%s: unsupported IPv6 jumbogram\n", __func__)); 413 m_freem(m); 414 return EMSGSIZE; 415 } 416 417 ip6.ip6_flow = 0; 418 ip6.ip6_hlim = 0; 419 ip6.ip6_vfc &= ~IPV6_VERSION_MASK; 420 ip6.ip6_vfc |= IPV6_VERSION; 421 422 /* Scoped address handling. */ 423 if (IN6_IS_SCOPE_LINKLOCAL(&ip6.ip6_src)) 424 ip6.ip6_src.s6_addr16[1] = 0; 425 if (IN6_IS_SCOPE_LINKLOCAL(&ip6.ip6_dst)) 426 ip6.ip6_dst.s6_addr16[1] = 0; 427 428 /* Done with IPv6 header. */ 429 m_copyback(m, 0, sizeof(struct ip6_hdr), (caddr_t) &ip6); 430 431 /* Let's deal with the remaining headers (if any). */ 432 if (skip - sizeof(struct ip6_hdr) > 0) { 433 if (m->m_len <= skip) { 434 ptr = (unsigned char *) malloc( 435 skip - sizeof(struct ip6_hdr), 436 M_XDATA, M_NOWAIT); 437 if (ptr == NULL) { 438 DPRINTF(("%s: failed to allocate memory" 439 "for IPv6 headers\n",__func__)); 440 m_freem(m); 441 return ENOBUFS; 442 } 443 444 /* 445 * Copy all the protocol headers after 446 * the IPv6 header. 447 */ 448 m_copydata(m, sizeof(struct ip6_hdr), 449 skip - sizeof(struct ip6_hdr), ptr); 450 alloc = 1; 451 } else { 452 /* No need to allocate memory. */ 453 ptr = mtod(m, unsigned char *) + 454 sizeof(struct ip6_hdr); 455 alloc = 0; 456 } 457 } else 458 break; 459 460 nxt = ip6.ip6_nxt & 0xff; /* Next header type. */ 461 462 for (off = 0; off < skip - sizeof(struct ip6_hdr);) 463 switch (nxt) { 464 case IPPROTO_HOPOPTS: 465 case IPPROTO_DSTOPTS: 466 ip6e = (struct ip6_ext *)(ptr + off); 467 noff = off + ((ip6e->ip6e_len + 1) << 3); 468 469 /* Sanity check. */ 470 if (noff > skip - sizeof(struct ip6_hdr)) 471 goto error6; 472 473 /* 474 * Zero out mutable options. 475 */ 476 for (count = off + sizeof(struct ip6_ext); 477 count < noff;) { 478 if (ptr[count] == IP6OPT_PAD1) { 479 count++; 480 continue; /* Skip padding. */ 481 } 482 483 ad = ptr[count + 1] + 2; 484 if (count + ad > noff) 485 goto error6; 486 487 if (ptr[count] & IP6OPT_MUTABLE) 488 memset(ptr + count, 0, ad); 489 count += ad; 490 } 491 492 if (count != noff) 493 goto error6; 494 495 /* Advance. */ 496 off += ((ip6e->ip6e_len + 1) << 3); 497 nxt = ip6e->ip6e_nxt; 498 break; 499 500 case IPPROTO_ROUTING: 501 /* 502 * Always include routing headers in 503 * computation. 504 */ 505 ip6e = (struct ip6_ext *) (ptr + off); 506 off += ((ip6e->ip6e_len + 1) << 3); 507 nxt = ip6e->ip6e_nxt; 508 break; 509 510 default: 511 DPRINTF(("%s: unexpected IPv6 header type %d", 512 __func__, off)); 513 error6: 514 if (alloc) 515 free(ptr, M_XDATA); 516 m_freem(m); 517 return EINVAL; 518 } 519 520 /* Copyback and free, if we allocated. */ 521 if (alloc) { 522 m_copyback(m, sizeof(struct ip6_hdr), 523 skip - sizeof(struct ip6_hdr), ptr); 524 free(ptr, M_XDATA); 525 } 526 527 break; 528 #endif /* INET6 */ 529 } 530 531 return 0; 532 } 533 534 /* 535 * ah_input() gets called to verify that an input packet 536 * passes authentication. 537 */ 538 static int 539 ah_input(struct mbuf *m, struct secasvar *sav, int skip, int protoff) 540 { 541 IPSEC_DEBUG_DECLARE(char buf[128]); 542 const struct auth_hash *ahx; 543 struct cryptodesc *crda; 544 struct cryptop *crp; 545 struct xform_data *xd; 546 struct newah *ah; 547 uint64_t cryptoid; 548 int hl, rplen, authsize, ahsize, error; 549 550 IPSEC_ASSERT(sav != NULL, ("null SA")); 551 IPSEC_ASSERT(sav->key_auth != NULL, ("null authentication key")); 552 IPSEC_ASSERT(sav->tdb_authalgxform != NULL, 553 ("null authentication xform")); 554 555 /* Figure out header size. */ 556 rplen = HDRSIZE(sav); 557 558 /* XXX don't pullup, just copy header */ 559 IP6_EXTHDR_GET(ah, struct newah *, m, skip, rplen); 560 if (ah == NULL) { 561 DPRINTF(("ah_input: cannot pullup header\n")); 562 AHSTAT_INC(ahs_hdrops); /*XXX*/ 563 error = ENOBUFS; 564 goto bad; 565 } 566 567 /* Check replay window, if applicable. */ 568 SECASVAR_LOCK(sav); 569 if (sav->replay != NULL && sav->replay->wsize != 0 && 570 ipsec_chkreplay(ntohl(ah->ah_seq), sav) == 0) { 571 SECASVAR_UNLOCK(sav); 572 AHSTAT_INC(ahs_replay); 573 DPRINTF(("%s: packet replay failure: %s\n", __func__, 574 ipsec_sa2str(sav, buf, sizeof(buf)))); 575 error = EACCES; 576 goto bad; 577 } 578 cryptoid = sav->tdb_cryptoid; 579 SECASVAR_UNLOCK(sav); 580 581 /* Verify AH header length. */ 582 hl = sizeof(struct ah) + (ah->ah_len * sizeof (u_int32_t)); 583 ahx = sav->tdb_authalgxform; 584 authsize = AUTHSIZE(sav); 585 ahsize = ah_hdrsiz(sav); 586 if (hl != ahsize) { 587 DPRINTF(("%s: bad authenticator length %u (expecting %lu)" 588 " for packet in SA %s/%08lx\n", __func__, hl, 589 (u_long)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 if (skip + ahsize > m->m_pkthdr.len) { 597 DPRINTF(("%s: bad mbuf length %u (expecting %lu)" 598 " for packet in SA %s/%08lx\n", __func__, 599 m->m_pkthdr.len, (u_long)(skip + ahsize), 600 ipsec_address(&sav->sah->saidx.dst, buf, sizeof(buf)), 601 (u_long) ntohl(sav->spi))); 602 AHSTAT_INC(ahs_badauthl); 603 error = EACCES; 604 goto bad; 605 } 606 AHSTAT_ADD(ahs_ibytes, m->m_pkthdr.len - skip - hl); 607 608 /* Get crypto descriptors. */ 609 crp = crypto_getreq(1); 610 if (crp == NULL) { 611 DPRINTF(("%s: failed to acquire crypto descriptor\n", 612 __func__)); 613 AHSTAT_INC(ahs_crypto); 614 error = ENOBUFS; 615 goto bad; 616 } 617 618 crda = crp->crp_desc; 619 IPSEC_ASSERT(crda != NULL, ("null crypto descriptor")); 620 621 crda->crd_skip = 0; 622 crda->crd_len = m->m_pkthdr.len; 623 crda->crd_inject = skip + rplen; 624 625 /* Authentication operation. */ 626 crda->crd_alg = ahx->type; 627 crda->crd_klen = _KEYBITS(sav->key_auth); 628 crda->crd_key = sav->key_auth->key_data; 629 630 /* Allocate IPsec-specific opaque crypto info. */ 631 xd = malloc(sizeof(*xd) + skip + rplen + authsize, M_XDATA, 632 M_NOWAIT | M_ZERO); 633 if (xd == NULL) { 634 DPRINTF(("%s: failed to allocate xform_data\n", __func__)); 635 AHSTAT_INC(ahs_crypto); 636 crypto_freereq(crp); 637 error = ENOBUFS; 638 goto bad; 639 } 640 641 /* 642 * Save the authenticator, the skipped portion of the packet, 643 * and the AH header. 644 */ 645 m_copydata(m, 0, skip + rplen + authsize, (caddr_t)(xd + 1)); 646 647 /* Zeroize the authenticator on the packet. */ 648 m_copyback(m, skip + rplen, authsize, ipseczeroes); 649 650 /* Save ah_nxt, since ah pointer can become invalid after "massage" */ 651 hl = ah->ah_nxt; 652 653 /* "Massage" the packet headers for crypto processing. */ 654 error = ah_massage_headers(&m, sav->sah->saidx.dst.sa.sa_family, 655 skip, ahx->type, 0); 656 if (error != 0) { 657 /* NB: mbuf is free'd by ah_massage_headers */ 658 AHSTAT_INC(ahs_hdrops); 659 free(xd, M_XDATA); 660 crypto_freereq(crp); 661 key_freesav(&sav); 662 return (error); 663 } 664 665 /* Crypto operation descriptor. */ 666 crp->crp_ilen = m->m_pkthdr.len; /* Total input length. */ 667 crp->crp_flags = CRYPTO_F_IMBUF | CRYPTO_F_CBIFSYNC; 668 if (V_async_crypto) 669 crp->crp_flags |= CRYPTO_F_ASYNC | CRYPTO_F_ASYNC_KEEPORDER; 670 crp->crp_buf = (caddr_t) m; 671 crp->crp_callback = ah_input_cb; 672 crp->crp_sid = cryptoid; 673 crp->crp_opaque = (caddr_t) xd; 674 675 /* These are passed as-is to the callback. */ 676 xd->sav = sav; 677 xd->nxt = hl; 678 xd->protoff = protoff; 679 xd->skip = skip; 680 xd->cryptoid = cryptoid; 681 xd->vnet = curvnet; 682 return (crypto_dispatch(crp)); 683 bad: 684 m_freem(m); 685 key_freesav(&sav); 686 return (error); 687 } 688 689 /* 690 * AH input callback from the crypto driver. 691 */ 692 static int 693 ah_input_cb(struct cryptop *crp) 694 { 695 IPSEC_DEBUG_DECLARE(char buf[IPSEC_ADDRSTRLEN]); 696 unsigned char calc[AH_ALEN_MAX]; 697 struct mbuf *m; 698 struct xform_data *xd; 699 struct secasvar *sav; 700 struct secasindex *saidx; 701 caddr_t ptr; 702 uint64_t cryptoid; 703 int authsize, rplen, ahsize, error, skip, protoff; 704 uint8_t nxt; 705 706 m = (struct mbuf *) crp->crp_buf; 707 xd = (struct xform_data *) crp->crp_opaque; 708 CURVNET_SET(xd->vnet); 709 sav = xd->sav; 710 skip = xd->skip; 711 nxt = xd->nxt; 712 protoff = xd->protoff; 713 cryptoid = xd->cryptoid; 714 saidx = &sav->sah->saidx; 715 IPSEC_ASSERT(saidx->dst.sa.sa_family == AF_INET || 716 saidx->dst.sa.sa_family == AF_INET6, 717 ("unexpected protocol family %u", saidx->dst.sa.sa_family)); 718 719 /* Check for crypto errors. */ 720 if (crp->crp_etype) { 721 if (crp->crp_etype == EAGAIN) { 722 /* Reset the session ID */ 723 if (ipsec_updateid(sav, &crp->crp_sid, &cryptoid) != 0) 724 crypto_freesession(cryptoid); 725 xd->cryptoid = crp->crp_sid; 726 CURVNET_RESTORE(); 727 return (crypto_dispatch(crp)); 728 } 729 AHSTAT_INC(ahs_noxform); 730 DPRINTF(("%s: crypto error %d\n", __func__, crp->crp_etype)); 731 error = crp->crp_etype; 732 goto bad; 733 } else { 734 AHSTAT_INC(ahs_hist[sav->alg_auth]); 735 crypto_freereq(crp); /* No longer needed. */ 736 crp = NULL; 737 } 738 739 /* Shouldn't happen... */ 740 if (m == NULL) { 741 AHSTAT_INC(ahs_crypto); 742 DPRINTF(("%s: bogus returned buffer from crypto\n", __func__)); 743 error = EINVAL; 744 goto bad; 745 } 746 747 /* Figure out header size. */ 748 rplen = HDRSIZE(sav); 749 authsize = AUTHSIZE(sav); 750 ahsize = ah_hdrsiz(sav); 751 752 /* Copy authenticator off the packet. */ 753 m_copydata(m, skip + rplen, authsize, calc); 754 755 /* Verify authenticator. */ 756 ptr = (caddr_t) (xd + 1); 757 if (timingsafe_bcmp(ptr + skip + rplen, calc, authsize)) { 758 DPRINTF(("%s: authentication hash mismatch for packet " 759 "in SA %s/%08lx\n", __func__, 760 ipsec_address(&saidx->dst, buf, sizeof(buf)), 761 (u_long) ntohl(sav->spi))); 762 AHSTAT_INC(ahs_badauth); 763 error = EACCES; 764 goto bad; 765 } 766 /* Fix the Next Protocol field. */ 767 ((uint8_t *) ptr)[protoff] = nxt; 768 769 /* Copyback the saved (uncooked) network headers. */ 770 m_copyback(m, 0, skip, ptr); 771 free(xd, M_XDATA), xd = NULL; /* No longer needed */ 772 773 /* 774 * Header is now authenticated. 775 */ 776 m->m_flags |= M_AUTHIPHDR|M_AUTHIPDGM; 777 778 /* 779 * Update replay sequence number, if appropriate. 780 */ 781 if (sav->replay) { 782 u_int32_t seq; 783 784 m_copydata(m, skip + offsetof(struct newah, ah_seq), 785 sizeof (seq), (caddr_t) &seq); 786 SECASVAR_LOCK(sav); 787 if (ipsec_updatereplay(ntohl(seq), sav)) { 788 SECASVAR_UNLOCK(sav); 789 AHSTAT_INC(ahs_replay); 790 error = EACCES; 791 goto bad; 792 } 793 SECASVAR_UNLOCK(sav); 794 } 795 796 /* 797 * Remove the AH header and authenticator from the mbuf. 798 */ 799 error = m_striphdr(m, skip, ahsize); 800 if (error) { 801 DPRINTF(("%s: mangled mbuf chain for SA %s/%08lx\n", __func__, 802 ipsec_address(&saidx->dst, buf, sizeof(buf)), 803 (u_long) ntohl(sav->spi))); 804 AHSTAT_INC(ahs_hdrops); 805 goto bad; 806 } 807 808 switch (saidx->dst.sa.sa_family) { 809 #ifdef INET6 810 case AF_INET6: 811 error = ipsec6_common_input_cb(m, sav, skip, protoff); 812 break; 813 #endif 814 #ifdef INET 815 case AF_INET: 816 error = ipsec4_common_input_cb(m, sav, skip, protoff); 817 break; 818 #endif 819 default: 820 panic("%s: Unexpected address family: %d saidx=%p", __func__, 821 saidx->dst.sa.sa_family, saidx); 822 } 823 CURVNET_RESTORE(); 824 return error; 825 bad: 826 CURVNET_RESTORE(); 827 if (sav) 828 key_freesav(&sav); 829 if (m != NULL) 830 m_freem(m); 831 if (xd != NULL) 832 free(xd, M_XDATA); 833 if (crp != NULL) 834 crypto_freereq(crp); 835 return error; 836 } 837 838 /* 839 * AH output routine, called by ipsec[46]_perform_request(). 840 */ 841 static int 842 ah_output(struct mbuf *m, struct secpolicy *sp, struct secasvar *sav, 843 u_int idx, int skip, int protoff) 844 { 845 IPSEC_DEBUG_DECLARE(char buf[IPSEC_ADDRSTRLEN]); 846 const struct auth_hash *ahx; 847 struct cryptodesc *crda; 848 struct xform_data *xd; 849 struct mbuf *mi; 850 struct cryptop *crp; 851 struct newah *ah; 852 uint64_t cryptoid; 853 uint16_t iplen; 854 int error, rplen, authsize, ahsize, maxpacketsize, roff; 855 uint8_t prot; 856 857 IPSEC_ASSERT(sav != NULL, ("null SA")); 858 ahx = sav->tdb_authalgxform; 859 IPSEC_ASSERT(ahx != NULL, ("null authentication xform")); 860 861 AHSTAT_INC(ahs_output); 862 863 /* Figure out header size. */ 864 rplen = HDRSIZE(sav); 865 authsize = AUTHSIZE(sav); 866 ahsize = ah_hdrsiz(sav); 867 868 /* Check for maximum packet size violations. */ 869 switch (sav->sah->saidx.dst.sa.sa_family) { 870 #ifdef INET 871 case AF_INET: 872 maxpacketsize = IP_MAXPACKET; 873 break; 874 #endif /* INET */ 875 #ifdef INET6 876 case AF_INET6: 877 maxpacketsize = IPV6_MAXPACKET; 878 break; 879 #endif /* INET6 */ 880 default: 881 DPRINTF(("%s: unknown/unsupported protocol family %u, " 882 "SA %s/%08lx\n", __func__, 883 sav->sah->saidx.dst.sa.sa_family, 884 ipsec_address(&sav->sah->saidx.dst, buf, sizeof(buf)), 885 (u_long) ntohl(sav->spi))); 886 AHSTAT_INC(ahs_nopf); 887 error = EPFNOSUPPORT; 888 goto bad; 889 } 890 if (ahsize + m->m_pkthdr.len > maxpacketsize) { 891 DPRINTF(("%s: packet in SA %s/%08lx got too big " 892 "(len %u, max len %u)\n", __func__, 893 ipsec_address(&sav->sah->saidx.dst, buf, sizeof(buf)), 894 (u_long) ntohl(sav->spi), 895 ahsize + m->m_pkthdr.len, maxpacketsize)); 896 AHSTAT_INC(ahs_toobig); 897 error = EMSGSIZE; 898 goto bad; 899 } 900 901 /* Update the counters. */ 902 AHSTAT_ADD(ahs_obytes, m->m_pkthdr.len - skip); 903 904 m = m_unshare(m, M_NOWAIT); 905 if (m == NULL) { 906 DPRINTF(("%s: cannot clone mbuf chain, SA %s/%08lx\n", __func__, 907 ipsec_address(&sav->sah->saidx.dst, buf, sizeof(buf)), 908 (u_long) ntohl(sav->spi))); 909 AHSTAT_INC(ahs_hdrops); 910 error = ENOBUFS; 911 goto bad; 912 } 913 914 /* Inject AH header. */ 915 mi = m_makespace(m, skip, ahsize, &roff); 916 if (mi == NULL) { 917 DPRINTF(("%s: failed to inject %u byte AH header for SA " 918 "%s/%08lx\n", __func__, ahsize, 919 ipsec_address(&sav->sah->saidx.dst, buf, sizeof(buf)), 920 (u_long) ntohl(sav->spi))); 921 AHSTAT_INC(ahs_hdrops); /*XXX differs from openbsd */ 922 error = ENOBUFS; 923 goto bad; 924 } 925 926 /* 927 * The AH header is guaranteed by m_makespace() to be in 928 * contiguous memory, at roff bytes offset into the returned mbuf. 929 */ 930 ah = (struct newah *)(mtod(mi, caddr_t) + roff); 931 932 /* Initialize the AH header. */ 933 m_copydata(m, protoff, sizeof(u_int8_t), (caddr_t) &ah->ah_nxt); 934 ah->ah_len = (ahsize - sizeof(struct ah)) / sizeof(u_int32_t); 935 ah->ah_reserve = 0; 936 ah->ah_spi = sav->spi; 937 938 /* Zeroize authenticator. */ 939 m_copyback(m, skip + rplen, authsize, ipseczeroes); 940 941 /* Zeroize padding */ 942 m_copyback(m, skip + rplen + authsize, ahsize - (rplen + authsize), 943 ipseczeroes); 944 945 /* Insert packet replay counter, as requested. */ 946 SECASVAR_LOCK(sav); 947 if (sav->replay) { 948 if (sav->replay->count == ~0 && 949 (sav->flags & SADB_X_EXT_CYCSEQ) == 0) { 950 SECASVAR_UNLOCK(sav); 951 DPRINTF(("%s: replay counter wrapped for SA %s/%08lx\n", 952 __func__, ipsec_address(&sav->sah->saidx.dst, buf, 953 sizeof(buf)), (u_long) ntohl(sav->spi))); 954 AHSTAT_INC(ahs_wrap); 955 error = EACCES; 956 goto bad; 957 } 958 #ifdef REGRESSION 959 /* Emulate replay attack when ipsec_replay is TRUE. */ 960 if (!V_ipsec_replay) 961 #endif 962 sav->replay->count++; 963 ah->ah_seq = htonl(sav->replay->count); 964 } 965 cryptoid = sav->tdb_cryptoid; 966 SECASVAR_UNLOCK(sav); 967 968 /* Get crypto descriptors. */ 969 crp = crypto_getreq(1); 970 if (crp == NULL) { 971 DPRINTF(("%s: failed to acquire crypto descriptors\n", 972 __func__)); 973 AHSTAT_INC(ahs_crypto); 974 error = ENOBUFS; 975 goto bad; 976 } 977 978 crda = crp->crp_desc; 979 crda->crd_skip = 0; 980 crda->crd_inject = skip + rplen; 981 crda->crd_len = m->m_pkthdr.len; 982 983 /* Authentication operation. */ 984 crda->crd_alg = ahx->type; 985 crda->crd_key = sav->key_auth->key_data; 986 crda->crd_klen = _KEYBITS(sav->key_auth); 987 988 /* Allocate IPsec-specific opaque crypto info. */ 989 xd = malloc(sizeof(struct xform_data) + skip, M_XDATA, 990 M_NOWAIT | M_ZERO); 991 if (xd == NULL) { 992 crypto_freereq(crp); 993 DPRINTF(("%s: failed to allocate xform_data\n", __func__)); 994 AHSTAT_INC(ahs_crypto); 995 error = ENOBUFS; 996 goto bad; 997 } 998 999 /* Save the skipped portion of the packet. */ 1000 m_copydata(m, 0, skip, (caddr_t) (xd + 1)); 1001 1002 /* 1003 * Fix IP header length on the header used for 1004 * authentication. We don't need to fix the original 1005 * header length as it will be fixed by our caller. 1006 */ 1007 switch (sav->sah->saidx.dst.sa.sa_family) { 1008 #ifdef INET 1009 case AF_INET: 1010 bcopy(((caddr_t)(xd + 1)) + 1011 offsetof(struct ip, ip_len), 1012 (caddr_t) &iplen, sizeof(u_int16_t)); 1013 iplen = htons(ntohs(iplen) + ahsize); 1014 m_copyback(m, offsetof(struct ip, ip_len), 1015 sizeof(u_int16_t), (caddr_t) &iplen); 1016 break; 1017 #endif /* INET */ 1018 1019 #ifdef INET6 1020 case AF_INET6: 1021 bcopy(((caddr_t)(xd + 1)) + 1022 offsetof(struct ip6_hdr, ip6_plen), 1023 (caddr_t) &iplen, sizeof(uint16_t)); 1024 iplen = htons(ntohs(iplen) + ahsize); 1025 m_copyback(m, offsetof(struct ip6_hdr, ip6_plen), 1026 sizeof(uint16_t), (caddr_t) &iplen); 1027 break; 1028 #endif /* INET6 */ 1029 } 1030 1031 /* Fix the Next Header field in saved header. */ 1032 ((uint8_t *) (xd + 1))[protoff] = IPPROTO_AH; 1033 1034 /* Update the Next Protocol field in the IP header. */ 1035 prot = IPPROTO_AH; 1036 m_copyback(m, protoff, sizeof(uint8_t), (caddr_t) &prot); 1037 1038 /* "Massage" the packet headers for crypto processing. */ 1039 error = ah_massage_headers(&m, sav->sah->saidx.dst.sa.sa_family, 1040 skip, ahx->type, 1); 1041 if (error != 0) { 1042 m = NULL; /* mbuf was free'd by ah_massage_headers. */ 1043 free(xd, M_XDATA); 1044 crypto_freereq(crp); 1045 goto bad; 1046 } 1047 1048 /* Crypto operation descriptor. */ 1049 crp->crp_ilen = m->m_pkthdr.len; /* Total input length. */ 1050 crp->crp_flags = CRYPTO_F_IMBUF | CRYPTO_F_CBIFSYNC; 1051 if (V_async_crypto) 1052 crp->crp_flags |= CRYPTO_F_ASYNC | CRYPTO_F_ASYNC_KEEPORDER; 1053 crp->crp_buf = (caddr_t) m; 1054 crp->crp_callback = ah_output_cb; 1055 crp->crp_sid = cryptoid; 1056 crp->crp_opaque = (caddr_t) xd; 1057 1058 /* These are passed as-is to the callback. */ 1059 xd->sp = sp; 1060 xd->sav = sav; 1061 xd->skip = skip; 1062 xd->idx = idx; 1063 xd->cryptoid = cryptoid; 1064 xd->vnet = curvnet; 1065 1066 return crypto_dispatch(crp); 1067 bad: 1068 if (m) 1069 m_freem(m); 1070 key_freesav(&sav); 1071 key_freesp(&sp); 1072 return (error); 1073 } 1074 1075 /* 1076 * AH output callback from the crypto driver. 1077 */ 1078 static int 1079 ah_output_cb(struct cryptop *crp) 1080 { 1081 struct xform_data *xd; 1082 struct secpolicy *sp; 1083 struct secasvar *sav; 1084 struct mbuf *m; 1085 uint64_t cryptoid; 1086 caddr_t ptr; 1087 u_int idx; 1088 int skip, error; 1089 1090 m = (struct mbuf *) crp->crp_buf; 1091 xd = (struct xform_data *) crp->crp_opaque; 1092 CURVNET_SET(xd->vnet); 1093 sp = xd->sp; 1094 sav = xd->sav; 1095 skip = xd->skip; 1096 idx = xd->idx; 1097 cryptoid = xd->cryptoid; 1098 ptr = (caddr_t) (xd + 1); 1099 1100 /* Check for crypto errors. */ 1101 if (crp->crp_etype) { 1102 if (crp->crp_etype == EAGAIN) { 1103 /* Reset the session ID */ 1104 if (ipsec_updateid(sav, &crp->crp_sid, &cryptoid) != 0) 1105 crypto_freesession(cryptoid); 1106 xd->cryptoid = crp->crp_sid; 1107 CURVNET_RESTORE(); 1108 return (crypto_dispatch(crp)); 1109 } 1110 AHSTAT_INC(ahs_noxform); 1111 DPRINTF(("%s: crypto error %d\n", __func__, crp->crp_etype)); 1112 error = crp->crp_etype; 1113 m_freem(m); 1114 goto bad; 1115 } 1116 1117 /* Shouldn't happen... */ 1118 if (m == NULL) { 1119 AHSTAT_INC(ahs_crypto); 1120 DPRINTF(("%s: bogus returned buffer from crypto\n", __func__)); 1121 error = EINVAL; 1122 goto bad; 1123 } 1124 /* 1125 * Copy original headers (with the new protocol number) back 1126 * in place. 1127 */ 1128 m_copyback(m, 0, skip, ptr); 1129 1130 free(xd, M_XDATA); 1131 crypto_freereq(crp); 1132 AHSTAT_INC(ahs_hist[sav->alg_auth]); 1133 #ifdef REGRESSION 1134 /* Emulate man-in-the-middle attack when ipsec_integrity is TRUE. */ 1135 if (V_ipsec_integrity) { 1136 int alen; 1137 1138 /* 1139 * Corrupt HMAC if we want to test integrity verification of 1140 * the other side. 1141 */ 1142 alen = AUTHSIZE(sav); 1143 m_copyback(m, m->m_pkthdr.len - alen, alen, ipseczeroes); 1144 } 1145 #endif 1146 1147 /* NB: m is reclaimed by ipsec_process_done. */ 1148 error = ipsec_process_done(m, sp, sav, idx); 1149 CURVNET_RESTORE(); 1150 return (error); 1151 bad: 1152 CURVNET_RESTORE(); 1153 free(xd, M_XDATA); 1154 crypto_freereq(crp); 1155 key_freesav(&sav); 1156 key_freesp(&sp); 1157 return (error); 1158 } 1159 1160 static struct xformsw ah_xformsw = { 1161 .xf_type = XF_AH, 1162 .xf_name = "IPsec AH", 1163 .xf_init = ah_init, 1164 .xf_zeroize = ah_zeroize, 1165 .xf_input = ah_input, 1166 .xf_output = ah_output, 1167 }; 1168 1169 SYSINIT(ah_xform_init, SI_SUB_PROTO_DOMAIN, SI_ORDER_MIDDLE, 1170 xform_attach, &ah_xformsw); 1171 SYSUNINIT(ah_xform_uninit, SI_SUB_PROTO_DOMAIN, SI_ORDER_MIDDLE, 1172 xform_detach, &ah_xformsw); 1173