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 static struct timeval md5warn, ripewarn, kpdkmd5warn, kpdksha1warn; 112 static struct timeval warninterval = { .tv_sec = 1, .tv_usec = 0 }; 113 114 static int ah_input_cb(struct cryptop*); 115 static int ah_output_cb(struct cryptop*); 116 117 int 118 xform_ah_authsize(const struct auth_hash *esph) 119 { 120 int alen; 121 122 if (esph == NULL) 123 return 0; 124 125 switch (esph->type) { 126 case CRYPTO_SHA2_256_HMAC: 127 case CRYPTO_SHA2_384_HMAC: 128 case CRYPTO_SHA2_512_HMAC: 129 alen = esph->hashsize / 2; /* RFC4868 2.3 */ 130 break; 131 132 case CRYPTO_AES_128_NIST_GMAC: 133 case CRYPTO_AES_192_NIST_GMAC: 134 case CRYPTO_AES_256_NIST_GMAC: 135 alen = esph->hashsize; 136 break; 137 138 default: 139 alen = AH_HMAC_HASHLEN; 140 break; 141 } 142 143 return alen; 144 } 145 146 size_t 147 ah_hdrsiz(struct secasvar *sav) 148 { 149 size_t size; 150 151 if (sav != NULL) { 152 int authsize, rplen, align; 153 154 IPSEC_ASSERT(sav->tdb_authalgxform != NULL, ("null xform")); 155 /*XXX not right for null algorithm--does it matter??*/ 156 157 /* RFC4302: use the correct alignment. */ 158 align = sizeof(uint32_t); 159 #ifdef INET6 160 if (sav->sah->saidx.dst.sa.sa_family == AF_INET6) { 161 align = sizeof(uint64_t); 162 } 163 #endif 164 rplen = HDRSIZE(sav); 165 authsize = AUTHSIZE(sav); 166 size = roundup(rplen + authsize, align); 167 } else { 168 /* default guess */ 169 size = sizeof (struct ah) + sizeof (u_int32_t) + 16; 170 } 171 return size; 172 } 173 174 /* 175 * NB: public for use by esp_init. 176 */ 177 int 178 ah_init0(struct secasvar *sav, struct xformsw *xsp, struct cryptoini *cria) 179 { 180 const struct auth_hash *thash; 181 int keylen; 182 183 thash = auth_algorithm_lookup(sav->alg_auth); 184 if (thash == NULL) { 185 DPRINTF(("%s: unsupported authentication algorithm %u\n", 186 __func__, sav->alg_auth)); 187 return EINVAL; 188 } 189 190 switch (sav->alg_auth) { 191 case SADB_AALG_MD5HMAC: 192 if (ratecheck(&md5warn, &warninterval)) 193 gone_in(13, "MD5-HMAC authenticator for IPsec"); 194 break; 195 case SADB_X_AALG_RIPEMD160HMAC: 196 if (ratecheck(&ripewarn, &warninterval)) 197 gone_in(13, "RIPEMD160-HMAC authenticator for IPsec"); 198 break; 199 case SADB_X_AALG_MD5: 200 if (ratecheck(&kpdkmd5warn, &warninterval)) 201 gone_in(13, "Keyed-MD5 authenticator for IPsec"); 202 break; 203 case SADB_X_AALG_SHA: 204 if (ratecheck(&kpdksha1warn, &warninterval)) 205 gone_in(13, "Keyed-SHA1 authenticator for IPsec"); 206 break; 207 } 208 209 /* 210 * Verify the replay state block allocation is consistent with 211 * the protocol type. We check here so we can make assumptions 212 * later during protocol processing. 213 */ 214 /* NB: replay state is setup elsewhere (sigh) */ 215 if (((sav->flags&SADB_X_EXT_OLD) == 0) ^ (sav->replay != NULL)) { 216 DPRINTF(("%s: replay state block inconsistency, " 217 "%s algorithm %s replay state\n", __func__, 218 (sav->flags & SADB_X_EXT_OLD) ? "old" : "new", 219 sav->replay == NULL ? "without" : "with")); 220 return EINVAL; 221 } 222 if (sav->key_auth == NULL) { 223 DPRINTF(("%s: no authentication key for %s algorithm\n", 224 __func__, thash->name)); 225 return EINVAL; 226 } 227 keylen = _KEYLEN(sav->key_auth); 228 if (keylen > thash->keysize && thash->keysize != 0) { 229 DPRINTF(("%s: invalid keylength %d, algorithm %s requires " 230 "keysize less than %d\n", __func__, 231 keylen, thash->name, thash->keysize)); 232 return EINVAL; 233 } 234 235 sav->tdb_xform = xsp; 236 sav->tdb_authalgxform = thash; 237 238 /* Initialize crypto session. */ 239 bzero(cria, sizeof (*cria)); 240 cria->cri_alg = sav->tdb_authalgxform->type; 241 cria->cri_klen = _KEYBITS(sav->key_auth); 242 cria->cri_key = sav->key_auth->key_data; 243 cria->cri_mlen = AUTHSIZE(sav); 244 245 return 0; 246 } 247 248 /* 249 * ah_init() is called when an SPI is being set up. 250 */ 251 static int 252 ah_init(struct secasvar *sav, struct xformsw *xsp) 253 { 254 struct cryptoini cria; 255 int error; 256 257 error = ah_init0(sav, xsp, &cria); 258 return error ? error : 259 crypto_newsession(&sav->tdb_cryptoid, &cria, V_crypto_support); 260 } 261 262 /* 263 * Paranoia. 264 * 265 * NB: public for use by esp_zeroize (XXX). 266 */ 267 int 268 ah_zeroize(struct secasvar *sav) 269 { 270 271 if (sav->key_auth) 272 bzero(sav->key_auth->key_data, _KEYLEN(sav->key_auth)); 273 274 crypto_freesession(sav->tdb_cryptoid); 275 sav->tdb_cryptoid = NULL; 276 sav->tdb_authalgxform = NULL; 277 sav->tdb_xform = NULL; 278 return 0; 279 } 280 281 /* 282 * Massage IPv4/IPv6 headers for AH processing. 283 */ 284 static int 285 ah_massage_headers(struct mbuf **m0, int proto, int skip, int alg, int out) 286 { 287 struct mbuf *m = *m0; 288 unsigned char *ptr; 289 int off, count; 290 291 #ifdef INET 292 struct ip *ip; 293 #endif /* INET */ 294 295 #ifdef INET6 296 struct ip6_ext *ip6e; 297 struct ip6_hdr ip6; 298 int ad, alloc, nxt, noff; 299 #endif /* INET6 */ 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(("%s: m_pullup failed\n", __func__)); 312 return ENOBUFS; 313 } 314 315 /* Fix the IP header */ 316 ip = mtod(m, struct ip *); 317 if (V_ah_cleartos) 318 ip->ip_tos = 0; 319 ip->ip_ttl = 0; 320 ip->ip_sum = 0; 321 322 if (alg == CRYPTO_MD5_KPDK || alg == CRYPTO_SHA1_KPDK) 323 ip->ip_off &= htons(IP_DF); 324 else 325 ip->ip_off = htons(0); 326 327 ptr = mtod(m, unsigned char *); 328 329 /* IPv4 option processing */ 330 for (off = sizeof(struct ip); off < skip;) { 331 if (ptr[off] == IPOPT_EOL || ptr[off] == IPOPT_NOP || 332 off + 1 < skip) 333 ; 334 else { 335 DPRINTF(("%s: illegal IPv4 option length for " 336 "option %d\n", __func__, ptr[off])); 337 338 m_freem(m); 339 return EINVAL; 340 } 341 342 switch (ptr[off]) { 343 case IPOPT_EOL: 344 off = skip; /* End the loop. */ 345 break; 346 347 case IPOPT_NOP: 348 off++; 349 break; 350 351 case IPOPT_SECURITY: /* 0x82 */ 352 case 0x85: /* Extended security. */ 353 case 0x86: /* Commercial security. */ 354 case 0x94: /* Router alert */ 355 case 0x95: /* RFC1770 */ 356 /* Sanity check for option length. */ 357 if (ptr[off + 1] < 2) { 358 DPRINTF(("%s: illegal IPv4 option " 359 "length for option %d\n", 360 __func__, ptr[off])); 361 362 m_freem(m); 363 return EINVAL; 364 } 365 366 off += ptr[off + 1]; 367 break; 368 369 case IPOPT_LSRR: 370 case IPOPT_SSRR: 371 /* Sanity check for option length. */ 372 if (ptr[off + 1] < 2) { 373 DPRINTF(("%s: illegal IPv4 option " 374 "length for option %d\n", 375 __func__, ptr[off])); 376 377 m_freem(m); 378 return EINVAL; 379 } 380 381 /* 382 * On output, if we have either of the 383 * source routing options, we should 384 * swap the destination address of the 385 * IP header with the last address 386 * specified in the option, as that is 387 * what the destination's IP header 388 * will look like. 389 */ 390 if (out) 391 bcopy(ptr + off + ptr[off + 1] - 392 sizeof(struct in_addr), 393 &(ip->ip_dst), sizeof(struct in_addr)); 394 395 /* Fall through */ 396 default: 397 /* Sanity check for option length. */ 398 if (ptr[off + 1] < 2) { 399 DPRINTF(("%s: illegal IPv4 option " 400 "length for option %d\n", 401 __func__, ptr[off])); 402 m_freem(m); 403 return EINVAL; 404 } 405 406 /* Zeroize all other options. */ 407 count = ptr[off + 1]; 408 bcopy(ipseczeroes, ptr + off, count); 409 off += count; 410 break; 411 } 412 413 /* Sanity check. */ 414 if (off > skip) { 415 DPRINTF(("%s: malformed IPv4 options header\n", 416 __func__)); 417 418 m_freem(m); 419 return EINVAL; 420 } 421 } 422 423 break; 424 #endif /* INET */ 425 426 #ifdef INET6 427 case AF_INET6: /* Ugly... */ 428 /* Copy and "cook" the IPv6 header. */ 429 m_copydata(m, 0, sizeof(ip6), (caddr_t) &ip6); 430 431 /* We don't do IPv6 Jumbograms. */ 432 if (ip6.ip6_plen == 0) { 433 DPRINTF(("%s: unsupported IPv6 jumbogram\n", __func__)); 434 m_freem(m); 435 return EMSGSIZE; 436 } 437 438 ip6.ip6_flow = 0; 439 ip6.ip6_hlim = 0; 440 ip6.ip6_vfc &= ~IPV6_VERSION_MASK; 441 ip6.ip6_vfc |= IPV6_VERSION; 442 443 /* Scoped address handling. */ 444 if (IN6_IS_SCOPE_LINKLOCAL(&ip6.ip6_src)) 445 ip6.ip6_src.s6_addr16[1] = 0; 446 if (IN6_IS_SCOPE_LINKLOCAL(&ip6.ip6_dst)) 447 ip6.ip6_dst.s6_addr16[1] = 0; 448 449 /* Done with IPv6 header. */ 450 m_copyback(m, 0, sizeof(struct ip6_hdr), (caddr_t) &ip6); 451 452 /* Let's deal with the remaining headers (if any). */ 453 if (skip - sizeof(struct ip6_hdr) > 0) { 454 if (m->m_len <= skip) { 455 ptr = (unsigned char *) malloc( 456 skip - sizeof(struct ip6_hdr), 457 M_XDATA, M_NOWAIT); 458 if (ptr == NULL) { 459 DPRINTF(("%s: failed to allocate memory" 460 "for IPv6 headers\n",__func__)); 461 m_freem(m); 462 return ENOBUFS; 463 } 464 465 /* 466 * Copy all the protocol headers after 467 * the IPv6 header. 468 */ 469 m_copydata(m, sizeof(struct ip6_hdr), 470 skip - sizeof(struct ip6_hdr), ptr); 471 alloc = 1; 472 } else { 473 /* No need to allocate memory. */ 474 ptr = mtod(m, unsigned char *) + 475 sizeof(struct ip6_hdr); 476 alloc = 0; 477 } 478 } else 479 break; 480 481 nxt = ip6.ip6_nxt & 0xff; /* Next header type. */ 482 483 for (off = 0; off < skip - sizeof(struct ip6_hdr);) 484 switch (nxt) { 485 case IPPROTO_HOPOPTS: 486 case IPPROTO_DSTOPTS: 487 ip6e = (struct ip6_ext *)(ptr + off); 488 noff = off + ((ip6e->ip6e_len + 1) << 3); 489 490 /* Sanity check. */ 491 if (noff > skip - sizeof(struct ip6_hdr)) 492 goto error6; 493 494 /* 495 * Zero out mutable options. 496 */ 497 for (count = off + sizeof(struct ip6_ext); 498 count < noff;) { 499 if (ptr[count] == IP6OPT_PAD1) { 500 count++; 501 continue; /* Skip padding. */ 502 } 503 504 ad = ptr[count + 1] + 2; 505 if (count + ad > noff) 506 goto error6; 507 508 if (ptr[count] & IP6OPT_MUTABLE) 509 memset(ptr + count, 0, ad); 510 count += ad; 511 } 512 513 if (count != noff) 514 goto error6; 515 516 /* Advance. */ 517 off += ((ip6e->ip6e_len + 1) << 3); 518 nxt = ip6e->ip6e_nxt; 519 break; 520 521 case IPPROTO_ROUTING: 522 /* 523 * Always include routing headers in 524 * computation. 525 */ 526 ip6e = (struct ip6_ext *) (ptr + off); 527 off += ((ip6e->ip6e_len + 1) << 3); 528 nxt = ip6e->ip6e_nxt; 529 break; 530 531 default: 532 DPRINTF(("%s: unexpected IPv6 header type %d", 533 __func__, off)); 534 error6: 535 if (alloc) 536 free(ptr, M_XDATA); 537 m_freem(m); 538 return EINVAL; 539 } 540 541 /* Copyback and free, if we allocated. */ 542 if (alloc) { 543 m_copyback(m, sizeof(struct ip6_hdr), 544 skip - sizeof(struct ip6_hdr), ptr); 545 free(ptr, M_XDATA); 546 } 547 548 break; 549 #endif /* INET6 */ 550 } 551 552 return 0; 553 } 554 555 /* 556 * ah_input() gets called to verify that an input packet 557 * passes authentication. 558 */ 559 static int 560 ah_input(struct mbuf *m, struct secasvar *sav, int skip, int protoff) 561 { 562 IPSEC_DEBUG_DECLARE(char buf[128]); 563 const struct auth_hash *ahx; 564 struct cryptodesc *crda; 565 struct cryptop *crp; 566 struct xform_data *xd; 567 struct newah *ah; 568 crypto_session_t cryptoid; 569 int hl, rplen, authsize, ahsize, error; 570 571 IPSEC_ASSERT(sav != NULL, ("null SA")); 572 IPSEC_ASSERT(sav->key_auth != NULL, ("null authentication key")); 573 IPSEC_ASSERT(sav->tdb_authalgxform != NULL, 574 ("null authentication xform")); 575 576 /* Figure out header size. */ 577 rplen = HDRSIZE(sav); 578 579 /* XXX don't pullup, just copy header */ 580 IP6_EXTHDR_GET(ah, struct newah *, m, skip, rplen); 581 if (ah == NULL) { 582 DPRINTF(("ah_input: cannot pullup header\n")); 583 AHSTAT_INC(ahs_hdrops); /*XXX*/ 584 error = ENOBUFS; 585 goto bad; 586 } 587 588 /* Check replay window, if applicable. */ 589 SECASVAR_LOCK(sav); 590 if (sav->replay != NULL && sav->replay->wsize != 0 && 591 ipsec_chkreplay(ntohl(ah->ah_seq), sav) == 0) { 592 SECASVAR_UNLOCK(sav); 593 AHSTAT_INC(ahs_replay); 594 DPRINTF(("%s: packet replay failure: %s\n", __func__, 595 ipsec_sa2str(sav, buf, sizeof(buf)))); 596 error = EACCES; 597 goto bad; 598 } 599 cryptoid = sav->tdb_cryptoid; 600 SECASVAR_UNLOCK(sav); 601 602 /* Verify AH header length. */ 603 hl = sizeof(struct ah) + (ah->ah_len * sizeof (u_int32_t)); 604 ahx = sav->tdb_authalgxform; 605 authsize = AUTHSIZE(sav); 606 ahsize = ah_hdrsiz(sav); 607 if (hl != ahsize) { 608 DPRINTF(("%s: bad authenticator length %u (expecting %lu)" 609 " for packet in SA %s/%08lx\n", __func__, hl, 610 (u_long)ahsize, 611 ipsec_address(&sav->sah->saidx.dst, buf, sizeof(buf)), 612 (u_long) ntohl(sav->spi))); 613 AHSTAT_INC(ahs_badauthl); 614 error = EACCES; 615 goto bad; 616 } 617 if (skip + ahsize > m->m_pkthdr.len) { 618 DPRINTF(("%s: bad mbuf length %u (expecting %lu)" 619 " for packet in SA %s/%08lx\n", __func__, 620 m->m_pkthdr.len, (u_long)(skip + ahsize), 621 ipsec_address(&sav->sah->saidx.dst, buf, sizeof(buf)), 622 (u_long) ntohl(sav->spi))); 623 AHSTAT_INC(ahs_badauthl); 624 error = EACCES; 625 goto bad; 626 } 627 AHSTAT_ADD(ahs_ibytes, m->m_pkthdr.len - skip - hl); 628 629 /* Get crypto descriptors. */ 630 crp = crypto_getreq(1); 631 if (crp == NULL) { 632 DPRINTF(("%s: failed to acquire crypto descriptor\n", 633 __func__)); 634 AHSTAT_INC(ahs_crypto); 635 error = ENOBUFS; 636 goto bad; 637 } 638 639 crda = crp->crp_desc; 640 IPSEC_ASSERT(crda != NULL, ("null crypto descriptor")); 641 642 crda->crd_skip = 0; 643 crda->crd_len = m->m_pkthdr.len; 644 crda->crd_inject = skip + rplen; 645 646 /* Authentication operation. */ 647 crda->crd_alg = ahx->type; 648 crda->crd_klen = _KEYBITS(sav->key_auth); 649 crda->crd_key = sav->key_auth->key_data; 650 651 /* Allocate IPsec-specific opaque crypto info. */ 652 xd = malloc(sizeof(*xd) + skip + rplen + authsize, M_XDATA, 653 M_NOWAIT | M_ZERO); 654 if (xd == NULL) { 655 DPRINTF(("%s: failed to allocate xform_data\n", __func__)); 656 AHSTAT_INC(ahs_crypto); 657 crypto_freereq(crp); 658 error = ENOBUFS; 659 goto bad; 660 } 661 662 /* 663 * Save the authenticator, the skipped portion of the packet, 664 * and the AH header. 665 */ 666 m_copydata(m, 0, skip + rplen + authsize, (caddr_t)(xd + 1)); 667 668 /* Zeroize the authenticator on the packet. */ 669 m_copyback(m, skip + rplen, authsize, ipseczeroes); 670 671 /* Save ah_nxt, since ah pointer can become invalid after "massage" */ 672 hl = ah->ah_nxt; 673 674 /* "Massage" the packet headers for crypto processing. */ 675 error = ah_massage_headers(&m, sav->sah->saidx.dst.sa.sa_family, 676 skip, ahx->type, 0); 677 if (error != 0) { 678 /* NB: mbuf is free'd by ah_massage_headers */ 679 AHSTAT_INC(ahs_hdrops); 680 free(xd, M_XDATA); 681 crypto_freereq(crp); 682 key_freesav(&sav); 683 return (error); 684 } 685 686 /* Crypto operation descriptor. */ 687 crp->crp_ilen = m->m_pkthdr.len; /* Total input length. */ 688 crp->crp_flags = CRYPTO_F_IMBUF | CRYPTO_F_CBIFSYNC; 689 if (V_async_crypto) 690 crp->crp_flags |= CRYPTO_F_ASYNC | CRYPTO_F_ASYNC_KEEPORDER; 691 crp->crp_buf = (caddr_t) m; 692 crp->crp_callback = ah_input_cb; 693 crp->crp_session = cryptoid; 694 crp->crp_opaque = (caddr_t) xd; 695 696 /* These are passed as-is to the callback. */ 697 xd->sav = sav; 698 xd->nxt = hl; 699 xd->protoff = protoff; 700 xd->skip = skip; 701 xd->cryptoid = cryptoid; 702 xd->vnet = curvnet; 703 return (crypto_dispatch(crp)); 704 bad: 705 m_freem(m); 706 key_freesav(&sav); 707 return (error); 708 } 709 710 /* 711 * AH input callback from the crypto driver. 712 */ 713 static int 714 ah_input_cb(struct cryptop *crp) 715 { 716 IPSEC_DEBUG_DECLARE(char buf[IPSEC_ADDRSTRLEN]); 717 unsigned char calc[AH_ALEN_MAX]; 718 struct mbuf *m; 719 struct xform_data *xd; 720 struct secasvar *sav; 721 struct secasindex *saidx; 722 caddr_t ptr; 723 crypto_session_t cryptoid; 724 int authsize, rplen, ahsize, error, skip, protoff; 725 uint8_t nxt; 726 727 m = (struct mbuf *) crp->crp_buf; 728 xd = (struct xform_data *) crp->crp_opaque; 729 CURVNET_SET(xd->vnet); 730 sav = xd->sav; 731 skip = xd->skip; 732 nxt = xd->nxt; 733 protoff = xd->protoff; 734 cryptoid = xd->cryptoid; 735 saidx = &sav->sah->saidx; 736 IPSEC_ASSERT(saidx->dst.sa.sa_family == AF_INET || 737 saidx->dst.sa.sa_family == AF_INET6, 738 ("unexpected protocol family %u", saidx->dst.sa.sa_family)); 739 740 /* Check for crypto errors. */ 741 if (crp->crp_etype) { 742 if (crp->crp_etype == EAGAIN) { 743 /* Reset the session ID */ 744 if (ipsec_updateid(sav, &crp->crp_session, &cryptoid) != 0) 745 crypto_freesession(cryptoid); 746 xd->cryptoid = crp->crp_session; 747 CURVNET_RESTORE(); 748 return (crypto_dispatch(crp)); 749 } 750 AHSTAT_INC(ahs_noxform); 751 DPRINTF(("%s: crypto error %d\n", __func__, crp->crp_etype)); 752 error = crp->crp_etype; 753 goto bad; 754 } else { 755 AHSTAT_INC(ahs_hist[sav->alg_auth]); 756 crypto_freereq(crp); /* No longer needed. */ 757 crp = NULL; 758 } 759 760 /* Shouldn't happen... */ 761 if (m == NULL) { 762 AHSTAT_INC(ahs_crypto); 763 DPRINTF(("%s: bogus returned buffer from crypto\n", __func__)); 764 error = EINVAL; 765 goto bad; 766 } 767 768 /* Figure out header size. */ 769 rplen = HDRSIZE(sav); 770 authsize = AUTHSIZE(sav); 771 ahsize = ah_hdrsiz(sav); 772 773 /* Copy authenticator off the packet. */ 774 m_copydata(m, skip + rplen, authsize, calc); 775 776 /* Verify authenticator. */ 777 ptr = (caddr_t) (xd + 1); 778 if (timingsafe_bcmp(ptr + skip + rplen, calc, authsize)) { 779 DPRINTF(("%s: authentication hash mismatch for packet " 780 "in SA %s/%08lx\n", __func__, 781 ipsec_address(&saidx->dst, buf, sizeof(buf)), 782 (u_long) ntohl(sav->spi))); 783 AHSTAT_INC(ahs_badauth); 784 error = EACCES; 785 goto bad; 786 } 787 /* Fix the Next Protocol field. */ 788 ((uint8_t *) ptr)[protoff] = nxt; 789 790 /* Copyback the saved (uncooked) network headers. */ 791 m_copyback(m, 0, skip, ptr); 792 free(xd, M_XDATA), xd = NULL; /* No longer needed */ 793 794 /* 795 * Header is now authenticated. 796 */ 797 m->m_flags |= M_AUTHIPHDR|M_AUTHIPDGM; 798 799 /* 800 * Update replay sequence number, if appropriate. 801 */ 802 if (sav->replay) { 803 u_int32_t seq; 804 805 m_copydata(m, skip + offsetof(struct newah, ah_seq), 806 sizeof (seq), (caddr_t) &seq); 807 SECASVAR_LOCK(sav); 808 if (ipsec_updatereplay(ntohl(seq), sav)) { 809 SECASVAR_UNLOCK(sav); 810 AHSTAT_INC(ahs_replay); 811 error = EACCES; 812 goto bad; 813 } 814 SECASVAR_UNLOCK(sav); 815 } 816 817 /* 818 * Remove the AH header and authenticator from the mbuf. 819 */ 820 error = m_striphdr(m, skip, ahsize); 821 if (error) { 822 DPRINTF(("%s: mangled mbuf chain for SA %s/%08lx\n", __func__, 823 ipsec_address(&saidx->dst, buf, sizeof(buf)), 824 (u_long) ntohl(sav->spi))); 825 AHSTAT_INC(ahs_hdrops); 826 goto bad; 827 } 828 829 switch (saidx->dst.sa.sa_family) { 830 #ifdef INET6 831 case AF_INET6: 832 error = ipsec6_common_input_cb(m, sav, skip, protoff); 833 break; 834 #endif 835 #ifdef INET 836 case AF_INET: 837 error = ipsec4_common_input_cb(m, sav, skip, protoff); 838 break; 839 #endif 840 default: 841 panic("%s: Unexpected address family: %d saidx=%p", __func__, 842 saidx->dst.sa.sa_family, saidx); 843 } 844 CURVNET_RESTORE(); 845 return error; 846 bad: 847 CURVNET_RESTORE(); 848 if (sav) 849 key_freesav(&sav); 850 if (m != NULL) 851 m_freem(m); 852 if (xd != NULL) 853 free(xd, M_XDATA); 854 if (crp != NULL) 855 crypto_freereq(crp); 856 return error; 857 } 858 859 /* 860 * AH output routine, called by ipsec[46]_perform_request(). 861 */ 862 static int 863 ah_output(struct mbuf *m, struct secpolicy *sp, struct secasvar *sav, 864 u_int idx, int skip, int protoff) 865 { 866 IPSEC_DEBUG_DECLARE(char buf[IPSEC_ADDRSTRLEN]); 867 const struct auth_hash *ahx; 868 struct cryptodesc *crda; 869 struct xform_data *xd; 870 struct mbuf *mi; 871 struct cryptop *crp; 872 struct newah *ah; 873 crypto_session_t cryptoid; 874 uint16_t iplen; 875 int error, rplen, authsize, ahsize, maxpacketsize, roff; 876 uint8_t prot; 877 878 IPSEC_ASSERT(sav != NULL, ("null SA")); 879 ahx = sav->tdb_authalgxform; 880 IPSEC_ASSERT(ahx != NULL, ("null authentication xform")); 881 882 AHSTAT_INC(ahs_output); 883 884 /* Figure out header size. */ 885 rplen = HDRSIZE(sav); 886 authsize = AUTHSIZE(sav); 887 ahsize = ah_hdrsiz(sav); 888 889 /* Check for maximum packet size violations. */ 890 switch (sav->sah->saidx.dst.sa.sa_family) { 891 #ifdef INET 892 case AF_INET: 893 maxpacketsize = IP_MAXPACKET; 894 break; 895 #endif /* INET */ 896 #ifdef INET6 897 case AF_INET6: 898 maxpacketsize = IPV6_MAXPACKET; 899 break; 900 #endif /* INET6 */ 901 default: 902 DPRINTF(("%s: unknown/unsupported protocol family %u, " 903 "SA %s/%08lx\n", __func__, 904 sav->sah->saidx.dst.sa.sa_family, 905 ipsec_address(&sav->sah->saidx.dst, buf, sizeof(buf)), 906 (u_long) ntohl(sav->spi))); 907 AHSTAT_INC(ahs_nopf); 908 error = EPFNOSUPPORT; 909 goto bad; 910 } 911 if (ahsize + m->m_pkthdr.len > maxpacketsize) { 912 DPRINTF(("%s: packet in SA %s/%08lx got too big " 913 "(len %u, max len %u)\n", __func__, 914 ipsec_address(&sav->sah->saidx.dst, buf, sizeof(buf)), 915 (u_long) ntohl(sav->spi), 916 ahsize + m->m_pkthdr.len, maxpacketsize)); 917 AHSTAT_INC(ahs_toobig); 918 error = EMSGSIZE; 919 goto bad; 920 } 921 922 /* Update the counters. */ 923 AHSTAT_ADD(ahs_obytes, m->m_pkthdr.len - skip); 924 925 m = m_unshare(m, M_NOWAIT); 926 if (m == NULL) { 927 DPRINTF(("%s: cannot clone mbuf chain, SA %s/%08lx\n", __func__, 928 ipsec_address(&sav->sah->saidx.dst, buf, sizeof(buf)), 929 (u_long) ntohl(sav->spi))); 930 AHSTAT_INC(ahs_hdrops); 931 error = ENOBUFS; 932 goto bad; 933 } 934 935 /* Inject AH header. */ 936 mi = m_makespace(m, skip, ahsize, &roff); 937 if (mi == NULL) { 938 DPRINTF(("%s: failed to inject %u byte AH header for SA " 939 "%s/%08lx\n", __func__, ahsize, 940 ipsec_address(&sav->sah->saidx.dst, buf, sizeof(buf)), 941 (u_long) ntohl(sav->spi))); 942 AHSTAT_INC(ahs_hdrops); /*XXX differs from openbsd */ 943 error = ENOBUFS; 944 goto bad; 945 } 946 947 /* 948 * The AH header is guaranteed by m_makespace() to be in 949 * contiguous memory, at roff bytes offset into the returned mbuf. 950 */ 951 ah = (struct newah *)(mtod(mi, caddr_t) + roff); 952 953 /* Initialize the AH header. */ 954 m_copydata(m, protoff, sizeof(u_int8_t), (caddr_t) &ah->ah_nxt); 955 ah->ah_len = (ahsize - sizeof(struct ah)) / sizeof(u_int32_t); 956 ah->ah_reserve = 0; 957 ah->ah_spi = sav->spi; 958 959 /* Zeroize authenticator. */ 960 m_copyback(m, skip + rplen, authsize, ipseczeroes); 961 962 /* Zeroize padding */ 963 m_copyback(m, skip + rplen + authsize, ahsize - (rplen + authsize), 964 ipseczeroes); 965 966 /* Insert packet replay counter, as requested. */ 967 SECASVAR_LOCK(sav); 968 if (sav->replay) { 969 if (sav->replay->count == ~0 && 970 (sav->flags & SADB_X_EXT_CYCSEQ) == 0) { 971 SECASVAR_UNLOCK(sav); 972 DPRINTF(("%s: replay counter wrapped for SA %s/%08lx\n", 973 __func__, ipsec_address(&sav->sah->saidx.dst, buf, 974 sizeof(buf)), (u_long) ntohl(sav->spi))); 975 AHSTAT_INC(ahs_wrap); 976 error = EACCES; 977 goto bad; 978 } 979 #ifdef REGRESSION 980 /* Emulate replay attack when ipsec_replay is TRUE. */ 981 if (!V_ipsec_replay) 982 #endif 983 sav->replay->count++; 984 ah->ah_seq = htonl(sav->replay->count); 985 } 986 cryptoid = sav->tdb_cryptoid; 987 SECASVAR_UNLOCK(sav); 988 989 /* Get crypto descriptors. */ 990 crp = crypto_getreq(1); 991 if (crp == NULL) { 992 DPRINTF(("%s: failed to acquire crypto descriptors\n", 993 __func__)); 994 AHSTAT_INC(ahs_crypto); 995 error = ENOBUFS; 996 goto bad; 997 } 998 999 crda = crp->crp_desc; 1000 crda->crd_skip = 0; 1001 crda->crd_inject = skip + rplen; 1002 crda->crd_len = m->m_pkthdr.len; 1003 1004 /* Authentication operation. */ 1005 crda->crd_alg = ahx->type; 1006 crda->crd_key = sav->key_auth->key_data; 1007 crda->crd_klen = _KEYBITS(sav->key_auth); 1008 1009 /* Allocate IPsec-specific opaque crypto info. */ 1010 xd = malloc(sizeof(struct xform_data) + skip, M_XDATA, 1011 M_NOWAIT | M_ZERO); 1012 if (xd == NULL) { 1013 crypto_freereq(crp); 1014 DPRINTF(("%s: failed to allocate xform_data\n", __func__)); 1015 AHSTAT_INC(ahs_crypto); 1016 error = ENOBUFS; 1017 goto bad; 1018 } 1019 1020 /* Save the skipped portion of the packet. */ 1021 m_copydata(m, 0, skip, (caddr_t) (xd + 1)); 1022 1023 /* 1024 * Fix IP header length on the header used for 1025 * authentication. We don't need to fix the original 1026 * header length as it will be fixed by our caller. 1027 */ 1028 switch (sav->sah->saidx.dst.sa.sa_family) { 1029 #ifdef INET 1030 case AF_INET: 1031 bcopy(((caddr_t)(xd + 1)) + 1032 offsetof(struct ip, ip_len), 1033 (caddr_t) &iplen, sizeof(u_int16_t)); 1034 iplen = htons(ntohs(iplen) + ahsize); 1035 m_copyback(m, offsetof(struct ip, ip_len), 1036 sizeof(u_int16_t), (caddr_t) &iplen); 1037 break; 1038 #endif /* INET */ 1039 1040 #ifdef INET6 1041 case AF_INET6: 1042 bcopy(((caddr_t)(xd + 1)) + 1043 offsetof(struct ip6_hdr, ip6_plen), 1044 (caddr_t) &iplen, sizeof(uint16_t)); 1045 iplen = htons(ntohs(iplen) + ahsize); 1046 m_copyback(m, offsetof(struct ip6_hdr, ip6_plen), 1047 sizeof(uint16_t), (caddr_t) &iplen); 1048 break; 1049 #endif /* INET6 */ 1050 } 1051 1052 /* Fix the Next Header field in saved header. */ 1053 ((uint8_t *) (xd + 1))[protoff] = IPPROTO_AH; 1054 1055 /* Update the Next Protocol field in the IP header. */ 1056 prot = IPPROTO_AH; 1057 m_copyback(m, protoff, sizeof(uint8_t), (caddr_t) &prot); 1058 1059 /* "Massage" the packet headers for crypto processing. */ 1060 error = ah_massage_headers(&m, sav->sah->saidx.dst.sa.sa_family, 1061 skip, ahx->type, 1); 1062 if (error != 0) { 1063 m = NULL; /* mbuf was free'd by ah_massage_headers. */ 1064 free(xd, M_XDATA); 1065 crypto_freereq(crp); 1066 goto bad; 1067 } 1068 1069 /* Crypto operation descriptor. */ 1070 crp->crp_ilen = m->m_pkthdr.len; /* Total input length. */ 1071 crp->crp_flags = CRYPTO_F_IMBUF | CRYPTO_F_CBIFSYNC; 1072 if (V_async_crypto) 1073 crp->crp_flags |= CRYPTO_F_ASYNC | CRYPTO_F_ASYNC_KEEPORDER; 1074 crp->crp_buf = (caddr_t) m; 1075 crp->crp_callback = ah_output_cb; 1076 crp->crp_session = cryptoid; 1077 crp->crp_opaque = (caddr_t) xd; 1078 1079 /* These are passed as-is to the callback. */ 1080 xd->sp = sp; 1081 xd->sav = sav; 1082 xd->skip = skip; 1083 xd->idx = idx; 1084 xd->cryptoid = cryptoid; 1085 xd->vnet = curvnet; 1086 1087 return crypto_dispatch(crp); 1088 bad: 1089 if (m) 1090 m_freem(m); 1091 key_freesav(&sav); 1092 key_freesp(&sp); 1093 return (error); 1094 } 1095 1096 /* 1097 * AH output callback from the crypto driver. 1098 */ 1099 static int 1100 ah_output_cb(struct cryptop *crp) 1101 { 1102 struct xform_data *xd; 1103 struct secpolicy *sp; 1104 struct secasvar *sav; 1105 struct mbuf *m; 1106 crypto_session_t cryptoid; 1107 caddr_t ptr; 1108 u_int idx; 1109 int skip, error; 1110 1111 m = (struct mbuf *) crp->crp_buf; 1112 xd = (struct xform_data *) crp->crp_opaque; 1113 CURVNET_SET(xd->vnet); 1114 sp = xd->sp; 1115 sav = xd->sav; 1116 skip = xd->skip; 1117 idx = xd->idx; 1118 cryptoid = xd->cryptoid; 1119 ptr = (caddr_t) (xd + 1); 1120 1121 /* Check for crypto errors. */ 1122 if (crp->crp_etype) { 1123 if (crp->crp_etype == EAGAIN) { 1124 /* Reset the session ID */ 1125 if (ipsec_updateid(sav, &crp->crp_session, &cryptoid) != 0) 1126 crypto_freesession(cryptoid); 1127 xd->cryptoid = crp->crp_session; 1128 CURVNET_RESTORE(); 1129 return (crypto_dispatch(crp)); 1130 } 1131 AHSTAT_INC(ahs_noxform); 1132 DPRINTF(("%s: crypto error %d\n", __func__, crp->crp_etype)); 1133 error = crp->crp_etype; 1134 m_freem(m); 1135 goto bad; 1136 } 1137 1138 /* Shouldn't happen... */ 1139 if (m == NULL) { 1140 AHSTAT_INC(ahs_crypto); 1141 DPRINTF(("%s: bogus returned buffer from crypto\n", __func__)); 1142 error = EINVAL; 1143 goto bad; 1144 } 1145 /* 1146 * Copy original headers (with the new protocol number) back 1147 * in place. 1148 */ 1149 m_copyback(m, 0, skip, ptr); 1150 1151 free(xd, M_XDATA); 1152 crypto_freereq(crp); 1153 AHSTAT_INC(ahs_hist[sav->alg_auth]); 1154 #ifdef REGRESSION 1155 /* Emulate man-in-the-middle attack when ipsec_integrity is TRUE. */ 1156 if (V_ipsec_integrity) { 1157 int alen; 1158 1159 /* 1160 * Corrupt HMAC if we want to test integrity verification of 1161 * the other side. 1162 */ 1163 alen = AUTHSIZE(sav); 1164 m_copyback(m, m->m_pkthdr.len - alen, alen, ipseczeroes); 1165 } 1166 #endif 1167 1168 /* NB: m is reclaimed by ipsec_process_done. */ 1169 error = ipsec_process_done(m, sp, sav, idx); 1170 CURVNET_RESTORE(); 1171 return (error); 1172 bad: 1173 CURVNET_RESTORE(); 1174 free(xd, M_XDATA); 1175 crypto_freereq(crp); 1176 key_freesav(&sav); 1177 key_freesp(&sp); 1178 return (error); 1179 } 1180 1181 static struct xformsw ah_xformsw = { 1182 .xf_type = XF_AH, 1183 .xf_name = "IPsec AH", 1184 .xf_init = ah_init, 1185 .xf_zeroize = ah_zeroize, 1186 .xf_input = ah_input, 1187 .xf_output = ah_output, 1188 }; 1189 1190 SYSINIT(ah_xform_init, SI_SUB_PROTO_DOMAIN, SI_ORDER_MIDDLE, 1191 xform_attach, &ah_xformsw); 1192 SYSUNINIT(ah_xform_uninit, SI_SUB_PROTO_DOMAIN, SI_ORDER_MIDDLE, 1193 xform_detach, &ah_xformsw); 1194