1 /* $FreeBSD$ */ 2 /* $OpenBSD: ip_ah.c,v 1.63 2001/06/26 06:18:58 angelos Exp $ */ 3 /*- 4 * The authors of this code are John Ioannidis (ji@tla.org), 5 * Angelos D. Keromytis (kermit@csd.uch.gr) and 6 * Niels Provos (provos@physnet.uni-hamburg.de). 7 * 8 * The original version of this code was written by John Ioannidis 9 * for BSD/OS in Athens, Greece, in November 1995. 10 * 11 * Ported to OpenBSD and NetBSD, with additional transforms, in December 1996, 12 * by Angelos D. Keromytis. 13 * 14 * Additional transforms and features in 1997 and 1998 by Angelos D. Keromytis 15 * and Niels Provos. 16 * 17 * Additional features in 1999 by Angelos D. Keromytis and Niklas Hallqvist. 18 * 19 * Copyright (c) 1995, 1996, 1997, 1998, 1999 by John Ioannidis, 20 * Angelos D. Keromytis and Niels Provos. 21 * Copyright (c) 1999 Niklas Hallqvist. 22 * Copyright (c) 2001 Angelos D. Keromytis. 23 * 24 * Permission to use, copy, and modify this software with or without fee 25 * is hereby granted, provided that this entire notice is included in 26 * all copies of any software which is or includes a copy or 27 * modification of this software. 28 * You may use this code under the GNU public license if you so wish. Please 29 * contribute changes back to the authors under this freer than GPL license 30 * so that we may further the use of strong encryption without limitations to 31 * all. 32 * 33 * THIS SOFTWARE IS BEING PROVIDED "AS IS", WITHOUT ANY EXPRESS OR 34 * IMPLIED WARRANTY. IN PARTICULAR, NONE OF THE AUTHORS MAKES ANY 35 * REPRESENTATION OR WARRANTY OF ANY KIND CONCERNING THE 36 * MERCHANTABILITY OF THIS SOFTWARE OR ITS FITNESS FOR ANY PARTICULAR 37 * PURPOSE. 38 */ 39 #include "opt_inet.h" 40 #include "opt_inet6.h" 41 #include "opt_ipsec.h" 42 43 #include <sys/param.h> 44 #include <sys/systm.h> 45 #include <sys/mbuf.h> 46 #include <sys/socket.h> 47 #include <sys/syslog.h> 48 #include <sys/kernel.h> 49 #include <sys/lock.h> 50 #include <sys/mutex.h> 51 #include <sys/sysctl.h> 52 53 #include <net/if.h> 54 #include <net/vnet.h> 55 56 #include <netinet/in.h> 57 #include <netinet/in_systm.h> 58 #include <netinet/ip.h> 59 #include <netinet/ip_ecn.h> 60 #include <netinet/ip6.h> 61 62 #include <netipsec/ipsec.h> 63 #include <netipsec/ah.h> 64 #include <netipsec/ah_var.h> 65 #include <netipsec/xform.h> 66 67 #ifdef INET6 68 #include <netinet6/ip6_var.h> 69 #include <netipsec/ipsec6.h> 70 #include <netinet6/ip6_ecn.h> 71 #endif 72 73 #include <netipsec/key.h> 74 #include <netipsec/key_debug.h> 75 76 #include <opencrypto/cryptodev.h> 77 78 /* 79 * Return header size in bytes. The old protocol did not support 80 * the replay counter; the new protocol always includes the counter. 81 */ 82 #define HDRSIZE(sav) \ 83 (((sav)->flags & SADB_X_EXT_OLD) ? \ 84 sizeof (struct ah) : sizeof (struct ah) + sizeof (u_int32_t)) 85 /* 86 * Return authenticator size in bytes, based on a field in the 87 * algorithm descriptor. 88 */ 89 #define AUTHSIZE(sav) ((sav->flags & SADB_X_EXT_OLD) ? 16 : \ 90 xform_ah_authsize((sav)->tdb_authalgxform)) 91 92 VNET_DEFINE(int, ah_enable) = 1; /* control flow of packets with AH */ 93 VNET_DEFINE(int, ah_cleartos) = 1; /* clear ip_tos when doing AH calc */ 94 VNET_PCPUSTAT_DEFINE(struct ahstat, ahstat); 95 VNET_PCPUSTAT_SYSINIT(ahstat); 96 97 #ifdef VIMAGE 98 VNET_PCPUSTAT_SYSUNINIT(ahstat); 99 #endif /* VIMAGE */ 100 101 #ifdef INET 102 SYSCTL_DECL(_net_inet_ah); 103 SYSCTL_INT(_net_inet_ah, OID_AUTO, ah_enable, 104 CTLFLAG_VNET | CTLFLAG_RW, &VNET_NAME(ah_enable), 0, ""); 105 SYSCTL_INT(_net_inet_ah, OID_AUTO, ah_cleartos, 106 CTLFLAG_VNET | CTLFLAG_RW, &VNET_NAME(ah_cleartos), 0, ""); 107 SYSCTL_VNET_PCPUSTAT(_net_inet_ah, IPSECCTL_STATS, stats, struct ahstat, 108 ahstat, "AH statistics (struct ahstat, netipsec/ah_var.h)"); 109 #endif 110 111 static unsigned char ipseczeroes[256]; /* larger than an ip6 extension hdr */ 112 113 static int ah_input_cb(struct cryptop*); 114 static int ah_output_cb(struct cryptop*); 115 116 int 117 xform_ah_authsize(const struct auth_hash *esph) 118 { 119 int alen; 120 121 if (esph == NULL) 122 return 0; 123 124 switch (esph->type) { 125 case CRYPTO_SHA2_256_HMAC: 126 case CRYPTO_SHA2_384_HMAC: 127 case CRYPTO_SHA2_512_HMAC: 128 alen = esph->hashsize / 2; /* RFC4868 2.3 */ 129 break; 130 131 case CRYPTO_AES_NIST_GMAC: 132 alen = esph->hashsize; 133 break; 134 135 default: 136 alen = AH_HMAC_HASHLEN; 137 break; 138 } 139 140 return alen; 141 } 142 143 size_t 144 ah_hdrsiz(struct secasvar *sav) 145 { 146 size_t size; 147 148 if (sav != NULL) { 149 int authsize, rplen, align; 150 151 IPSEC_ASSERT(sav->tdb_authalgxform != NULL, ("null xform")); 152 /*XXX not right for null algorithm--does it matter??*/ 153 154 /* RFC4302: use the correct alignment. */ 155 align = sizeof(uint32_t); 156 #ifdef INET6 157 if (sav->sah->saidx.dst.sa.sa_family == AF_INET6) { 158 align = sizeof(uint64_t); 159 } 160 #endif 161 rplen = HDRSIZE(sav); 162 authsize = AUTHSIZE(sav); 163 size = roundup(rplen + authsize, align); 164 } else { 165 /* default guess */ 166 size = sizeof (struct ah) + sizeof (u_int32_t) + 16; 167 } 168 return size; 169 } 170 171 /* 172 * NB: public for use by esp_init. 173 */ 174 int 175 ah_init0(struct secasvar *sav, struct xformsw *xsp, 176 struct crypto_session_params *csp) 177 { 178 const struct auth_hash *thash; 179 int keylen; 180 181 thash = auth_algorithm_lookup(sav->alg_auth); 182 if (thash == NULL) { 183 DPRINTF(("%s: unsupported authentication algorithm %u\n", 184 __func__, sav->alg_auth)); 185 return EINVAL; 186 } 187 188 /* 189 * Verify the replay state block allocation is consistent with 190 * the protocol type. We check here so we can make assumptions 191 * later during protocol processing. 192 */ 193 /* NB: replay state is setup elsewhere (sigh) */ 194 if (((sav->flags&SADB_X_EXT_OLD) == 0) ^ (sav->replay != NULL)) { 195 DPRINTF(("%s: replay state block inconsistency, " 196 "%s algorithm %s replay state\n", __func__, 197 (sav->flags & SADB_X_EXT_OLD) ? "old" : "new", 198 sav->replay == NULL ? "without" : "with")); 199 return EINVAL; 200 } 201 if (sav->key_auth == NULL) { 202 DPRINTF(("%s: no authentication key for %s algorithm\n", 203 __func__, thash->name)); 204 return EINVAL; 205 } 206 keylen = _KEYLEN(sav->key_auth); 207 if (keylen > thash->keysize && thash->keysize != 0) { 208 DPRINTF(("%s: invalid keylength %d, algorithm %s requires " 209 "keysize less than %d\n", __func__, 210 keylen, thash->name, thash->keysize)); 211 return EINVAL; 212 } 213 214 sav->tdb_xform = xsp; 215 sav->tdb_authalgxform = thash; 216 217 /* Initialize crypto session. */ 218 csp->csp_auth_alg = sav->tdb_authalgxform->type; 219 if (csp->csp_auth_alg != CRYPTO_NULL_HMAC) { 220 csp->csp_auth_klen = _KEYBITS(sav->key_auth) / 8; 221 csp->csp_auth_key = sav->key_auth->key_data; 222 }; 223 csp->csp_auth_mlen = AUTHSIZE(sav); 224 225 return 0; 226 } 227 228 /* 229 * ah_init() is called when an SPI is being set up. 230 */ 231 static int 232 ah_init(struct secasvar *sav, struct xformsw *xsp) 233 { 234 struct crypto_session_params csp; 235 int error; 236 237 memset(&csp, 0, sizeof(csp)); 238 csp.csp_mode = CSP_MODE_DIGEST; 239 error = ah_init0(sav, xsp, &csp); 240 return error ? error : 241 crypto_newsession(&sav->tdb_cryptoid, &csp, V_crypto_support); 242 } 243 244 /* 245 * Paranoia. 246 * 247 * NB: public for use by esp_zeroize (XXX). 248 */ 249 int 250 ah_zeroize(struct secasvar *sav) 251 { 252 253 if (sav->key_auth) 254 bzero(sav->key_auth->key_data, _KEYLEN(sav->key_auth)); 255 256 crypto_freesession(sav->tdb_cryptoid); 257 sav->tdb_cryptoid = NULL; 258 sav->tdb_authalgxform = NULL; 259 sav->tdb_xform = NULL; 260 return 0; 261 } 262 263 /* 264 * Massage IPv4/IPv6 headers for AH processing. 265 */ 266 static int 267 ah_massage_headers(struct mbuf **m0, int proto, int skip, int alg, int out) 268 { 269 struct mbuf *m = *m0; 270 unsigned char *ptr; 271 int off, count; 272 273 #ifdef INET 274 struct ip *ip; 275 #endif /* INET */ 276 277 #ifdef INET6 278 struct ip6_ext *ip6e; 279 struct ip6_hdr ip6; 280 int ad, alloc, nxt, noff; 281 #endif /* INET6 */ 282 283 switch (proto) { 284 #ifdef INET 285 case AF_INET: 286 /* 287 * This is the least painful way of dealing with IPv4 header 288 * and option processing -- just make sure they're in 289 * contiguous memory. 290 */ 291 *m0 = m = m_pullup(m, skip); 292 if (m == NULL) { 293 DPRINTF(("%s: m_pullup failed\n", __func__)); 294 return ENOBUFS; 295 } 296 297 /* Fix the IP header */ 298 ip = mtod(m, struct ip *); 299 if (V_ah_cleartos) 300 ip->ip_tos = 0; 301 ip->ip_ttl = 0; 302 ip->ip_sum = 0; 303 ip->ip_off = htons(0); 304 305 ptr = mtod(m, unsigned char *); 306 307 /* IPv4 option processing */ 308 for (off = sizeof(struct ip); off < skip;) { 309 if (ptr[off] == IPOPT_EOL || ptr[off] == IPOPT_NOP || 310 off + 1 < skip) 311 ; 312 else { 313 DPRINTF(("%s: illegal IPv4 option length for " 314 "option %d\n", __func__, ptr[off])); 315 316 m_freem(m); 317 return EINVAL; 318 } 319 320 switch (ptr[off]) { 321 case IPOPT_EOL: 322 off = skip; /* End the loop. */ 323 break; 324 325 case IPOPT_NOP: 326 off++; 327 break; 328 329 case IPOPT_SECURITY: /* 0x82 */ 330 case 0x85: /* Extended security. */ 331 case 0x86: /* Commercial security. */ 332 case 0x94: /* Router alert */ 333 case 0x95: /* RFC1770 */ 334 /* Sanity check for option length. */ 335 if (ptr[off + 1] < 2) { 336 DPRINTF(("%s: illegal IPv4 option " 337 "length for option %d\n", 338 __func__, ptr[off])); 339 340 m_freem(m); 341 return EINVAL; 342 } 343 344 off += ptr[off + 1]; 345 break; 346 347 case IPOPT_LSRR: 348 case IPOPT_SSRR: 349 /* Sanity check for option length. */ 350 if (ptr[off + 1] < 2) { 351 DPRINTF(("%s: illegal IPv4 option " 352 "length for option %d\n", 353 __func__, ptr[off])); 354 355 m_freem(m); 356 return EINVAL; 357 } 358 359 /* 360 * On output, if we have either of the 361 * source routing options, we should 362 * swap the destination address of the 363 * IP header with the last address 364 * specified in the option, as that is 365 * what the destination's IP header 366 * will look like. 367 */ 368 if (out) 369 bcopy(ptr + off + ptr[off + 1] - 370 sizeof(struct in_addr), 371 &(ip->ip_dst), sizeof(struct in_addr)); 372 373 /* Fall through */ 374 default: 375 /* Sanity check for option length. */ 376 if (ptr[off + 1] < 2) { 377 DPRINTF(("%s: illegal IPv4 option " 378 "length for option %d\n", 379 __func__, ptr[off])); 380 m_freem(m); 381 return EINVAL; 382 } 383 384 /* Zeroize all other options. */ 385 count = ptr[off + 1]; 386 bcopy(ipseczeroes, ptr + off, count); 387 off += count; 388 break; 389 } 390 391 /* Sanity check. */ 392 if (off > skip) { 393 DPRINTF(("%s: malformed IPv4 options header\n", 394 __func__)); 395 396 m_freem(m); 397 return EINVAL; 398 } 399 } 400 401 break; 402 #endif /* INET */ 403 404 #ifdef INET6 405 case AF_INET6: /* Ugly... */ 406 /* Copy and "cook" the IPv6 header. */ 407 m_copydata(m, 0, sizeof(ip6), (caddr_t) &ip6); 408 409 /* We don't do IPv6 Jumbograms. */ 410 if (ip6.ip6_plen == 0) { 411 DPRINTF(("%s: unsupported IPv6 jumbogram\n", __func__)); 412 m_freem(m); 413 return EMSGSIZE; 414 } 415 416 ip6.ip6_flow = 0; 417 ip6.ip6_hlim = 0; 418 ip6.ip6_vfc &= ~IPV6_VERSION_MASK; 419 ip6.ip6_vfc |= IPV6_VERSION; 420 421 /* Scoped address handling. */ 422 if (IN6_IS_SCOPE_LINKLOCAL(&ip6.ip6_src)) 423 ip6.ip6_src.s6_addr16[1] = 0; 424 if (IN6_IS_SCOPE_LINKLOCAL(&ip6.ip6_dst)) 425 ip6.ip6_dst.s6_addr16[1] = 0; 426 427 /* Done with IPv6 header. */ 428 m_copyback(m, 0, sizeof(struct ip6_hdr), (caddr_t) &ip6); 429 430 /* Let's deal with the remaining headers (if any). */ 431 if (skip - sizeof(struct ip6_hdr) > 0) { 432 if (m->m_len <= skip) { 433 ptr = (unsigned char *) malloc( 434 skip - sizeof(struct ip6_hdr), 435 M_XDATA, M_NOWAIT); 436 if (ptr == NULL) { 437 DPRINTF(("%s: failed to allocate memory" 438 "for IPv6 headers\n",__func__)); 439 m_freem(m); 440 return ENOBUFS; 441 } 442 443 /* 444 * Copy all the protocol headers after 445 * the IPv6 header. 446 */ 447 m_copydata(m, sizeof(struct ip6_hdr), 448 skip - sizeof(struct ip6_hdr), ptr); 449 alloc = 1; 450 } else { 451 /* No need to allocate memory. */ 452 ptr = mtod(m, unsigned char *) + 453 sizeof(struct ip6_hdr); 454 alloc = 0; 455 } 456 } else 457 break; 458 459 nxt = ip6.ip6_nxt & 0xff; /* Next header type. */ 460 461 for (off = 0; off < skip - sizeof(struct ip6_hdr);) 462 switch (nxt) { 463 case IPPROTO_HOPOPTS: 464 case IPPROTO_DSTOPTS: 465 ip6e = (struct ip6_ext *)(ptr + off); 466 noff = off + ((ip6e->ip6e_len + 1) << 3); 467 468 /* Sanity check. */ 469 if (noff > skip - sizeof(struct ip6_hdr)) 470 goto error6; 471 472 /* 473 * Zero out mutable options. 474 */ 475 for (count = off + sizeof(struct ip6_ext); 476 count < noff;) { 477 if (ptr[count] == IP6OPT_PAD1) { 478 count++; 479 continue; /* Skip padding. */ 480 } 481 482 ad = ptr[count + 1] + 2; 483 if (count + ad > noff) 484 goto error6; 485 486 if (ptr[count] & IP6OPT_MUTABLE) 487 memset(ptr + count, 0, ad); 488 count += ad; 489 } 490 491 if (count != noff) 492 goto error6; 493 494 /* Advance. */ 495 off += ((ip6e->ip6e_len + 1) << 3); 496 nxt = ip6e->ip6e_nxt; 497 break; 498 499 case IPPROTO_ROUTING: 500 /* 501 * Always include routing headers in 502 * computation. 503 */ 504 ip6e = (struct ip6_ext *) (ptr + off); 505 off += ((ip6e->ip6e_len + 1) << 3); 506 nxt = ip6e->ip6e_nxt; 507 break; 508 509 default: 510 DPRINTF(("%s: unexpected IPv6 header type %d", 511 __func__, off)); 512 error6: 513 if (alloc) 514 free(ptr, M_XDATA); 515 m_freem(m); 516 return EINVAL; 517 } 518 519 /* Copyback and free, if we allocated. */ 520 if (alloc) { 521 m_copyback(m, sizeof(struct ip6_hdr), 522 skip - sizeof(struct ip6_hdr), ptr); 523 free(ptr, M_XDATA); 524 } 525 526 break; 527 #endif /* INET6 */ 528 } 529 530 return 0; 531 } 532 533 /* 534 * ah_input() gets called to verify that an input packet 535 * passes authentication. 536 */ 537 static int 538 ah_input(struct mbuf *m, struct secasvar *sav, int skip, int protoff) 539 { 540 IPSEC_DEBUG_DECLARE(char buf[128]); 541 const struct auth_hash *ahx; 542 struct cryptop *crp; 543 struct xform_data *xd; 544 struct newah *ah; 545 crypto_session_t cryptoid; 546 int hl, rplen, authsize, ahsize, error; 547 548 IPSEC_ASSERT(sav != NULL, ("null SA")); 549 IPSEC_ASSERT(sav->key_auth != NULL, ("null authentication key")); 550 IPSEC_ASSERT(sav->tdb_authalgxform != NULL, 551 ("null authentication xform")); 552 553 /* Figure out header size. */ 554 rplen = HDRSIZE(sav); 555 556 if (m->m_len < skip + rplen) { 557 m = m_pullup(m, skip + rplen); 558 if (m == NULL) { 559 DPRINTF(("ah_input: cannot pullup header\n")); 560 AHSTAT_INC(ahs_hdrops); /*XXX*/ 561 error = ENOBUFS; 562 goto bad; 563 } 564 } 565 ah = (struct newah *)(mtod(m, caddr_t) + skip); 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(cryptoid, M_NOWAIT); 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 crp->crp_payload_start = 0; 619 crp->crp_payload_length = m->m_pkthdr.len; 620 crp->crp_digest_start = skip + rplen; 621 622 /* Allocate IPsec-specific opaque crypto info. */ 623 xd = malloc(sizeof(*xd) + skip + rplen + authsize, M_XDATA, 624 M_NOWAIT | M_ZERO); 625 if (xd == NULL) { 626 DPRINTF(("%s: failed to allocate xform_data\n", __func__)); 627 AHSTAT_INC(ahs_crypto); 628 crypto_freereq(crp); 629 error = ENOBUFS; 630 goto bad; 631 } 632 633 /* 634 * Save the authenticator, the skipped portion of the packet, 635 * and the AH header. 636 */ 637 m_copydata(m, 0, skip + rplen + authsize, (caddr_t)(xd + 1)); 638 639 /* Zeroize the authenticator on the packet. */ 640 m_copyback(m, skip + rplen, authsize, ipseczeroes); 641 642 /* Save ah_nxt, since ah pointer can become invalid after "massage" */ 643 hl = ah->ah_nxt; 644 645 /* "Massage" the packet headers for crypto processing. */ 646 error = ah_massage_headers(&m, sav->sah->saidx.dst.sa.sa_family, 647 skip, ahx->type, 0); 648 if (error != 0) { 649 /* NB: mbuf is free'd by ah_massage_headers */ 650 AHSTAT_INC(ahs_hdrops); 651 free(xd, M_XDATA); 652 crypto_freereq(crp); 653 key_freesav(&sav); 654 return (error); 655 } 656 657 /* Crypto operation descriptor. */ 658 crp->crp_op = CRYPTO_OP_COMPUTE_DIGEST; 659 crp->crp_flags = CRYPTO_F_CBIFSYNC; 660 if (V_async_crypto) 661 crp->crp_flags |= CRYPTO_F_ASYNC | CRYPTO_F_ASYNC_KEEPORDER; 662 crypto_use_mbuf(crp, m); 663 crp->crp_callback = ah_input_cb; 664 crp->crp_opaque = xd; 665 666 /* These are passed as-is to the callback. */ 667 xd->sav = sav; 668 xd->nxt = hl; 669 xd->protoff = protoff; 670 xd->skip = skip; 671 xd->cryptoid = cryptoid; 672 xd->vnet = curvnet; 673 return (crypto_dispatch(crp)); 674 bad: 675 m_freem(m); 676 key_freesav(&sav); 677 return (error); 678 } 679 680 /* 681 * AH input callback from the crypto driver. 682 */ 683 static int 684 ah_input_cb(struct cryptop *crp) 685 { 686 IPSEC_DEBUG_DECLARE(char buf[IPSEC_ADDRSTRLEN]); 687 unsigned char calc[AH_ALEN_MAX]; 688 struct mbuf *m; 689 struct xform_data *xd; 690 struct secasvar *sav; 691 struct secasindex *saidx; 692 caddr_t ptr; 693 crypto_session_t cryptoid; 694 int authsize, rplen, ahsize, error, skip, protoff; 695 uint8_t nxt; 696 697 m = crp->crp_buf.cb_mbuf; 698 xd = crp->crp_opaque; 699 CURVNET_SET(xd->vnet); 700 sav = xd->sav; 701 skip = xd->skip; 702 nxt = xd->nxt; 703 protoff = xd->protoff; 704 cryptoid = xd->cryptoid; 705 saidx = &sav->sah->saidx; 706 IPSEC_ASSERT(saidx->dst.sa.sa_family == AF_INET || 707 saidx->dst.sa.sa_family == AF_INET6, 708 ("unexpected protocol family %u", saidx->dst.sa.sa_family)); 709 710 /* Check for crypto errors. */ 711 if (crp->crp_etype) { 712 if (crp->crp_etype == EAGAIN) { 713 /* Reset the session ID */ 714 if (ipsec_updateid(sav, &crp->crp_session, &cryptoid) != 0) 715 crypto_freesession(cryptoid); 716 xd->cryptoid = crp->crp_session; 717 CURVNET_RESTORE(); 718 return (crypto_dispatch(crp)); 719 } 720 AHSTAT_INC(ahs_noxform); 721 DPRINTF(("%s: crypto error %d\n", __func__, crp->crp_etype)); 722 error = crp->crp_etype; 723 goto bad; 724 } else { 725 AHSTAT_INC(ahs_hist[sav->alg_auth]); 726 crypto_freereq(crp); /* No longer needed. */ 727 crp = NULL; 728 } 729 730 /* Shouldn't happen... */ 731 if (m == NULL) { 732 AHSTAT_INC(ahs_crypto); 733 DPRINTF(("%s: bogus returned buffer from crypto\n", __func__)); 734 error = EINVAL; 735 goto bad; 736 } 737 738 /* Figure out header size. */ 739 rplen = HDRSIZE(sav); 740 authsize = AUTHSIZE(sav); 741 ahsize = ah_hdrsiz(sav); 742 743 /* Copy authenticator off the packet. */ 744 m_copydata(m, skip + rplen, authsize, calc); 745 746 /* Verify authenticator. */ 747 ptr = (caddr_t) (xd + 1); 748 if (timingsafe_bcmp(ptr + skip + rplen, calc, authsize)) { 749 DPRINTF(("%s: authentication hash mismatch for packet " 750 "in SA %s/%08lx\n", __func__, 751 ipsec_address(&saidx->dst, buf, sizeof(buf)), 752 (u_long) ntohl(sav->spi))); 753 AHSTAT_INC(ahs_badauth); 754 error = EACCES; 755 goto bad; 756 } 757 /* Fix the Next Protocol field. */ 758 ((uint8_t *) ptr)[protoff] = nxt; 759 760 /* Copyback the saved (uncooked) network headers. */ 761 m_copyback(m, 0, skip, ptr); 762 free(xd, M_XDATA), xd = NULL; /* No longer needed */ 763 764 /* 765 * Header is now authenticated. 766 */ 767 m->m_flags |= M_AUTHIPHDR|M_AUTHIPDGM; 768 769 /* 770 * Update replay sequence number, if appropriate. 771 */ 772 if (sav->replay) { 773 u_int32_t seq; 774 775 m_copydata(m, skip + offsetof(struct newah, ah_seq), 776 sizeof (seq), (caddr_t) &seq); 777 SECASVAR_LOCK(sav); 778 if (ipsec_updatereplay(ntohl(seq), sav)) { 779 SECASVAR_UNLOCK(sav); 780 AHSTAT_INC(ahs_replay); 781 error = EACCES; 782 goto bad; 783 } 784 SECASVAR_UNLOCK(sav); 785 } 786 787 /* 788 * Remove the AH header and authenticator from the mbuf. 789 */ 790 error = m_striphdr(m, skip, ahsize); 791 if (error) { 792 DPRINTF(("%s: mangled mbuf chain for SA %s/%08lx\n", __func__, 793 ipsec_address(&saidx->dst, buf, sizeof(buf)), 794 (u_long) ntohl(sav->spi))); 795 AHSTAT_INC(ahs_hdrops); 796 goto bad; 797 } 798 799 switch (saidx->dst.sa.sa_family) { 800 #ifdef INET6 801 case AF_INET6: 802 error = ipsec6_common_input_cb(m, sav, skip, protoff); 803 break; 804 #endif 805 #ifdef INET 806 case AF_INET: 807 error = ipsec4_common_input_cb(m, sav, skip, protoff); 808 break; 809 #endif 810 default: 811 panic("%s: Unexpected address family: %d saidx=%p", __func__, 812 saidx->dst.sa.sa_family, saidx); 813 } 814 CURVNET_RESTORE(); 815 return error; 816 bad: 817 CURVNET_RESTORE(); 818 if (sav) 819 key_freesav(&sav); 820 if (m != NULL) 821 m_freem(m); 822 if (xd != NULL) 823 free(xd, M_XDATA); 824 if (crp != NULL) 825 crypto_freereq(crp); 826 return error; 827 } 828 829 /* 830 * AH output routine, called by ipsec[46]_perform_request(). 831 */ 832 static int 833 ah_output(struct mbuf *m, struct secpolicy *sp, struct secasvar *sav, 834 u_int idx, int skip, int protoff) 835 { 836 IPSEC_DEBUG_DECLARE(char buf[IPSEC_ADDRSTRLEN]); 837 const struct auth_hash *ahx; 838 struct xform_data *xd; 839 struct mbuf *mi; 840 struct cryptop *crp; 841 struct newah *ah; 842 crypto_session_t cryptoid; 843 uint16_t iplen; 844 int error, rplen, authsize, ahsize, maxpacketsize, roff; 845 uint8_t prot; 846 847 IPSEC_ASSERT(sav != NULL, ("null SA")); 848 ahx = sav->tdb_authalgxform; 849 IPSEC_ASSERT(ahx != NULL, ("null authentication xform")); 850 851 AHSTAT_INC(ahs_output); 852 853 /* Figure out header size. */ 854 rplen = HDRSIZE(sav); 855 authsize = AUTHSIZE(sav); 856 ahsize = ah_hdrsiz(sav); 857 858 /* Check for maximum packet size violations. */ 859 switch (sav->sah->saidx.dst.sa.sa_family) { 860 #ifdef INET 861 case AF_INET: 862 maxpacketsize = IP_MAXPACKET; 863 break; 864 #endif /* INET */ 865 #ifdef INET6 866 case AF_INET6: 867 maxpacketsize = IPV6_MAXPACKET; 868 break; 869 #endif /* INET6 */ 870 default: 871 DPRINTF(("%s: unknown/unsupported protocol family %u, " 872 "SA %s/%08lx\n", __func__, 873 sav->sah->saidx.dst.sa.sa_family, 874 ipsec_address(&sav->sah->saidx.dst, buf, sizeof(buf)), 875 (u_long) ntohl(sav->spi))); 876 AHSTAT_INC(ahs_nopf); 877 error = EPFNOSUPPORT; 878 goto bad; 879 } 880 if (ahsize + m->m_pkthdr.len > maxpacketsize) { 881 DPRINTF(("%s: packet in SA %s/%08lx got too big " 882 "(len %u, max len %u)\n", __func__, 883 ipsec_address(&sav->sah->saidx.dst, buf, sizeof(buf)), 884 (u_long) ntohl(sav->spi), 885 ahsize + m->m_pkthdr.len, maxpacketsize)); 886 AHSTAT_INC(ahs_toobig); 887 error = EMSGSIZE; 888 goto bad; 889 } 890 891 /* Update the counters. */ 892 AHSTAT_ADD(ahs_obytes, m->m_pkthdr.len - skip); 893 894 m = m_unshare(m, M_NOWAIT); 895 if (m == NULL) { 896 DPRINTF(("%s: cannot clone mbuf chain, SA %s/%08lx\n", __func__, 897 ipsec_address(&sav->sah->saidx.dst, buf, sizeof(buf)), 898 (u_long) ntohl(sav->spi))); 899 AHSTAT_INC(ahs_hdrops); 900 error = ENOBUFS; 901 goto bad; 902 } 903 904 /* Inject AH header. */ 905 mi = m_makespace(m, skip, ahsize, &roff); 906 if (mi == NULL) { 907 DPRINTF(("%s: failed to inject %u byte AH header for SA " 908 "%s/%08lx\n", __func__, ahsize, 909 ipsec_address(&sav->sah->saidx.dst, buf, sizeof(buf)), 910 (u_long) ntohl(sav->spi))); 911 AHSTAT_INC(ahs_hdrops); /*XXX differs from openbsd */ 912 error = ENOBUFS; 913 goto bad; 914 } 915 916 /* 917 * The AH header is guaranteed by m_makespace() to be in 918 * contiguous memory, at roff bytes offset into the returned mbuf. 919 */ 920 ah = (struct newah *)(mtod(mi, caddr_t) + roff); 921 922 /* Initialize the AH header. */ 923 m_copydata(m, protoff, sizeof(u_int8_t), (caddr_t) &ah->ah_nxt); 924 ah->ah_len = (ahsize - sizeof(struct ah)) / sizeof(u_int32_t); 925 ah->ah_reserve = 0; 926 ah->ah_spi = sav->spi; 927 928 /* Zeroize authenticator. */ 929 m_copyback(m, skip + rplen, authsize, ipseczeroes); 930 931 /* Zeroize padding */ 932 m_copyback(m, skip + rplen + authsize, ahsize - (rplen + authsize), 933 ipseczeroes); 934 935 /* Insert packet replay counter, as requested. */ 936 SECASVAR_LOCK(sav); 937 if (sav->replay) { 938 if (sav->replay->count == ~0 && 939 (sav->flags & SADB_X_EXT_CYCSEQ) == 0) { 940 SECASVAR_UNLOCK(sav); 941 DPRINTF(("%s: replay counter wrapped for SA %s/%08lx\n", 942 __func__, ipsec_address(&sav->sah->saidx.dst, buf, 943 sizeof(buf)), (u_long) ntohl(sav->spi))); 944 AHSTAT_INC(ahs_wrap); 945 error = EACCES; 946 goto bad; 947 } 948 #ifdef REGRESSION 949 /* Emulate replay attack when ipsec_replay is TRUE. */ 950 if (!V_ipsec_replay) 951 #endif 952 sav->replay->count++; 953 ah->ah_seq = htonl(sav->replay->count); 954 } 955 cryptoid = sav->tdb_cryptoid; 956 SECASVAR_UNLOCK(sav); 957 958 /* Get crypto descriptors. */ 959 crp = crypto_getreq(cryptoid, M_NOWAIT); 960 if (crp == NULL) { 961 DPRINTF(("%s: failed to acquire crypto descriptors\n", 962 __func__)); 963 AHSTAT_INC(ahs_crypto); 964 error = ENOBUFS; 965 goto bad; 966 } 967 968 crp->crp_payload_start = 0; 969 crp->crp_payload_length = m->m_pkthdr.len; 970 crp->crp_digest_start = skip + rplen; 971 972 /* Allocate IPsec-specific opaque crypto info. */ 973 xd = malloc(sizeof(struct xform_data) + skip, M_XDATA, 974 M_NOWAIT | M_ZERO); 975 if (xd == NULL) { 976 crypto_freereq(crp); 977 DPRINTF(("%s: failed to allocate xform_data\n", __func__)); 978 AHSTAT_INC(ahs_crypto); 979 error = ENOBUFS; 980 goto bad; 981 } 982 983 /* Save the skipped portion of the packet. */ 984 m_copydata(m, 0, skip, (caddr_t) (xd + 1)); 985 986 /* 987 * Fix IP header length on the header used for 988 * authentication. We don't need to fix the original 989 * header length as it will be fixed by our caller. 990 */ 991 switch (sav->sah->saidx.dst.sa.sa_family) { 992 #ifdef INET 993 case AF_INET: 994 bcopy(((caddr_t)(xd + 1)) + 995 offsetof(struct ip, ip_len), 996 (caddr_t) &iplen, sizeof(u_int16_t)); 997 iplen = htons(ntohs(iplen) + ahsize); 998 m_copyback(m, offsetof(struct ip, ip_len), 999 sizeof(u_int16_t), (caddr_t) &iplen); 1000 break; 1001 #endif /* INET */ 1002 1003 #ifdef INET6 1004 case AF_INET6: 1005 bcopy(((caddr_t)(xd + 1)) + 1006 offsetof(struct ip6_hdr, ip6_plen), 1007 (caddr_t) &iplen, sizeof(uint16_t)); 1008 iplen = htons(ntohs(iplen) + ahsize); 1009 m_copyback(m, offsetof(struct ip6_hdr, ip6_plen), 1010 sizeof(uint16_t), (caddr_t) &iplen); 1011 break; 1012 #endif /* INET6 */ 1013 } 1014 1015 /* Fix the Next Header field in saved header. */ 1016 ((uint8_t *) (xd + 1))[protoff] = IPPROTO_AH; 1017 1018 /* Update the Next Protocol field in the IP header. */ 1019 prot = IPPROTO_AH; 1020 m_copyback(m, protoff, sizeof(uint8_t), (caddr_t) &prot); 1021 1022 /* "Massage" the packet headers for crypto processing. */ 1023 error = ah_massage_headers(&m, sav->sah->saidx.dst.sa.sa_family, 1024 skip, ahx->type, 1); 1025 if (error != 0) { 1026 m = NULL; /* mbuf was free'd by ah_massage_headers. */ 1027 free(xd, M_XDATA); 1028 crypto_freereq(crp); 1029 goto bad; 1030 } 1031 1032 /* Crypto operation descriptor. */ 1033 crp->crp_op = CRYPTO_OP_COMPUTE_DIGEST; 1034 crp->crp_flags = CRYPTO_F_CBIFSYNC; 1035 if (V_async_crypto) 1036 crp->crp_flags |= CRYPTO_F_ASYNC | CRYPTO_F_ASYNC_KEEPORDER; 1037 crypto_use_mbuf(crp, m); 1038 crp->crp_callback = ah_output_cb; 1039 crp->crp_opaque = xd; 1040 1041 /* These are passed as-is to the callback. */ 1042 xd->sp = sp; 1043 xd->sav = sav; 1044 xd->skip = skip; 1045 xd->idx = idx; 1046 xd->cryptoid = cryptoid; 1047 xd->vnet = curvnet; 1048 1049 return crypto_dispatch(crp); 1050 bad: 1051 if (m) 1052 m_freem(m); 1053 key_freesav(&sav); 1054 key_freesp(&sp); 1055 return (error); 1056 } 1057 1058 /* 1059 * AH output callback from the crypto driver. 1060 */ 1061 static int 1062 ah_output_cb(struct cryptop *crp) 1063 { 1064 struct xform_data *xd; 1065 struct secpolicy *sp; 1066 struct secasvar *sav; 1067 struct mbuf *m; 1068 crypto_session_t cryptoid; 1069 caddr_t ptr; 1070 u_int idx; 1071 int skip, error; 1072 1073 m = crp->crp_buf.cb_mbuf; 1074 xd = (struct xform_data *) crp->crp_opaque; 1075 CURVNET_SET(xd->vnet); 1076 sp = xd->sp; 1077 sav = xd->sav; 1078 skip = xd->skip; 1079 idx = xd->idx; 1080 cryptoid = xd->cryptoid; 1081 ptr = (caddr_t) (xd + 1); 1082 1083 /* Check for crypto errors. */ 1084 if (crp->crp_etype) { 1085 if (crp->crp_etype == EAGAIN) { 1086 /* Reset the session ID */ 1087 if (ipsec_updateid(sav, &crp->crp_session, &cryptoid) != 0) 1088 crypto_freesession(cryptoid); 1089 xd->cryptoid = crp->crp_session; 1090 CURVNET_RESTORE(); 1091 return (crypto_dispatch(crp)); 1092 } 1093 AHSTAT_INC(ahs_noxform); 1094 DPRINTF(("%s: crypto error %d\n", __func__, crp->crp_etype)); 1095 error = crp->crp_etype; 1096 m_freem(m); 1097 goto bad; 1098 } 1099 1100 /* Shouldn't happen... */ 1101 if (m == NULL) { 1102 AHSTAT_INC(ahs_crypto); 1103 DPRINTF(("%s: bogus returned buffer from crypto\n", __func__)); 1104 error = EINVAL; 1105 goto bad; 1106 } 1107 /* 1108 * Copy original headers (with the new protocol number) back 1109 * in place. 1110 */ 1111 m_copyback(m, 0, skip, ptr); 1112 1113 free(xd, M_XDATA); 1114 crypto_freereq(crp); 1115 AHSTAT_INC(ahs_hist[sav->alg_auth]); 1116 #ifdef REGRESSION 1117 /* Emulate man-in-the-middle attack when ipsec_integrity is TRUE. */ 1118 if (V_ipsec_integrity) { 1119 int alen; 1120 1121 /* 1122 * Corrupt HMAC if we want to test integrity verification of 1123 * the other side. 1124 */ 1125 alen = AUTHSIZE(sav); 1126 m_copyback(m, m->m_pkthdr.len - alen, alen, ipseczeroes); 1127 } 1128 #endif 1129 1130 /* NB: m is reclaimed by ipsec_process_done. */ 1131 error = ipsec_process_done(m, sp, sav, idx); 1132 CURVNET_RESTORE(); 1133 return (error); 1134 bad: 1135 CURVNET_RESTORE(); 1136 free(xd, M_XDATA); 1137 crypto_freereq(crp); 1138 key_freesav(&sav); 1139 key_freesp(&sp); 1140 return (error); 1141 } 1142 1143 static struct xformsw ah_xformsw = { 1144 .xf_type = XF_AH, 1145 .xf_name = "IPsec AH", 1146 .xf_init = ah_init, 1147 .xf_zeroize = ah_zeroize, 1148 .xf_input = ah_input, 1149 .xf_output = ah_output, 1150 }; 1151 1152 SYSINIT(ah_xform_init, SI_SUB_PROTO_DOMAIN, SI_ORDER_MIDDLE, 1153 xform_attach, &ah_xformsw); 1154 SYSUNINIT(ah_xform_uninit, SI_SUB_PROTO_DOMAIN, SI_ORDER_MIDDLE, 1155 xform_detach, &ah_xformsw); 1156