1 /* $OpenBSD: ip_ah.c,v 1.63 2001/06/26 06:18:58 angelos Exp $ */ 2 /*- 3 * The authors of this code are John Ioannidis (ji@tla.org), 4 * Angelos D. Keromytis (kermit@csd.uch.gr) and 5 * Niels Provos (provos@physnet.uni-hamburg.de). 6 * 7 * The original version of this code was written by John Ioannidis 8 * for BSD/OS in Athens, Greece, in November 1995. 9 * 10 * Ported to OpenBSD and NetBSD, with additional transforms, in December 1996, 11 * by Angelos D. Keromytis. 12 * 13 * Additional transforms and features in 1997 and 1998 by Angelos D. Keromytis 14 * and Niels Provos. 15 * 16 * Additional features in 1999 by Angelos D. Keromytis and Niklas Hallqvist. 17 * 18 * Copyright (c) 1995, 1996, 1997, 1998, 1999 by John Ioannidis, 19 * Angelos D. Keromytis and Niels Provos. 20 * Copyright (c) 1999 Niklas Hallqvist. 21 * Copyright (c) 2001 Angelos D. Keromytis. 22 * 23 * Permission to use, copy, and modify this software with or without fee 24 * is hereby granted, provided that this entire notice is included in 25 * all copies of any software which is or includes a copy or 26 * modification of this software. 27 * You may use this code under the GNU public license if you so wish. Please 28 * contribute changes back to the authors under this freer than GPL license 29 * so that we may further the use of strong encryption without limitations to 30 * all. 31 * 32 * THIS SOFTWARE IS BEING PROVIDED "AS IS", WITHOUT ANY EXPRESS OR 33 * IMPLIED WARRANTY. IN PARTICULAR, NONE OF THE AUTHORS MAKES ANY 34 * REPRESENTATION OR WARRANTY OF ANY KIND CONCERNING THE 35 * MERCHANTABILITY OF THIS SOFTWARE OR ITS FITNESS FOR ANY PARTICULAR 36 * PURPOSE. 37 */ 38 #include "opt_inet.h" 39 #include "opt_inet6.h" 40 #include "opt_ipsec.h" 41 42 #include <sys/param.h> 43 #include <sys/systm.h> 44 #include <sys/malloc.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 MALLOC_DEFINE(M_AH, "ah", "IPsec AH"); 112 113 static unsigned char ipseczeroes[256]; /* larger than an ip6 extension hdr */ 114 115 static int ah_input_cb(struct cryptop*); 116 static int ah_output_cb(struct cryptop*); 117 118 int 119 xform_ah_authsize(const struct auth_hash *esph) 120 { 121 int alen; 122 123 if (esph == NULL) 124 return 0; 125 126 switch (esph->type) { 127 case CRYPTO_SHA2_256_HMAC: 128 case CRYPTO_SHA2_384_HMAC: 129 case CRYPTO_SHA2_512_HMAC: 130 alen = esph->hashsize / 2; /* RFC4868 2.3 */ 131 break; 132 133 case CRYPTO_POLY1305: 134 case CRYPTO_AES_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, 179 struct crypto_session_params *csp) 180 { 181 const struct auth_hash *thash; 182 int keylen; 183 184 thash = auth_algorithm_lookup(sav->alg_auth); 185 if (thash == NULL) { 186 DPRINTF(("%s: unsupported authentication algorithm %u\n", 187 __func__, sav->alg_auth)); 188 return EINVAL; 189 } 190 191 /* 192 * Verify the replay state block allocation is consistent with 193 * the protocol type. We check here so we can make assumptions 194 * later during protocol processing. 195 */ 196 /* NB: replay state is setup elsewhere (sigh) */ 197 if (((sav->flags&SADB_X_EXT_OLD) == 0) ^ (sav->replay != NULL)) { 198 DPRINTF(("%s: replay state block inconsistency, " 199 "%s algorithm %s replay state\n", __func__, 200 (sav->flags & SADB_X_EXT_OLD) ? "old" : "new", 201 sav->replay == NULL ? "without" : "with")); 202 return EINVAL; 203 } 204 if (sav->key_auth == NULL) { 205 DPRINTF(("%s: no authentication key for %s algorithm\n", 206 __func__, thash->name)); 207 return EINVAL; 208 } 209 keylen = _KEYLEN(sav->key_auth); 210 if (keylen > thash->keysize && thash->keysize != 0) { 211 DPRINTF(("%s: invalid keylength %d, algorithm %s requires " 212 "keysize less than %d\n", __func__, 213 keylen, thash->name, thash->keysize)); 214 return EINVAL; 215 } 216 217 sav->tdb_xform = xsp; 218 sav->tdb_authalgxform = thash; 219 220 /* Initialize crypto session. */ 221 csp->csp_auth_alg = sav->tdb_authalgxform->type; 222 if (csp->csp_auth_alg != CRYPTO_NULL_HMAC) { 223 csp->csp_auth_klen = _KEYBITS(sav->key_auth) / 8; 224 csp->csp_auth_key = sav->key_auth->key_data; 225 }; 226 csp->csp_auth_mlen = AUTHSIZE(sav); 227 228 return 0; 229 } 230 231 /* 232 * ah_init() is called when an SPI is being set up. 233 */ 234 static int 235 ah_init(struct secasvar *sav, struct xformsw *xsp) 236 { 237 struct crypto_session_params csp; 238 int error; 239 240 memset(&csp, 0, sizeof(csp)); 241 csp.csp_mode = CSP_MODE_DIGEST; 242 243 if (sav->flags & SADB_X_SAFLAGS_ESN) 244 csp.csp_flags |= CSP_F_ESN; 245 246 error = ah_init0(sav, xsp, &csp); 247 return error ? error : 248 crypto_newsession(&sav->tdb_cryptoid, &csp, V_crypto_support); 249 } 250 251 static void 252 ah_cleanup(struct secasvar *sav) 253 { 254 255 crypto_freesession(sav->tdb_cryptoid); 256 sav->tdb_cryptoid = NULL; 257 sav->tdb_authalgxform = NULL; 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 ip->ip_off = htons(0); 301 302 ptr = mtod(m, unsigned char *); 303 304 /* IPv4 option processing */ 305 for (off = sizeof(struct ip); off < skip;) { 306 if (ptr[off] == IPOPT_EOL || ptr[off] == IPOPT_NOP || 307 off + 1 < skip) 308 ; 309 else { 310 DPRINTF(("%s: illegal IPv4 option length for " 311 "option %d\n", __func__, ptr[off])); 312 313 m_freem(m); 314 return EINVAL; 315 } 316 317 switch (ptr[off]) { 318 case IPOPT_EOL: 319 off = skip; /* End the loop. */ 320 break; 321 322 case IPOPT_NOP: 323 off++; 324 break; 325 326 case IPOPT_SECURITY: /* 0x82 */ 327 case 0x85: /* Extended security. */ 328 case 0x86: /* Commercial security. */ 329 case 0x94: /* Router alert */ 330 case 0x95: /* RFC1770 */ 331 /* Sanity check for option length. */ 332 if (ptr[off + 1] < 2) { 333 DPRINTF(("%s: illegal IPv4 option " 334 "length for option %d\n", 335 __func__, ptr[off])); 336 337 m_freem(m); 338 return EINVAL; 339 } 340 341 off += ptr[off + 1]; 342 break; 343 344 case IPOPT_LSRR: 345 case IPOPT_SSRR: 346 /* Sanity check for option length. */ 347 if (ptr[off + 1] < 2) { 348 DPRINTF(("%s: illegal IPv4 option " 349 "length for option %d\n", 350 __func__, ptr[off])); 351 352 m_freem(m); 353 return EINVAL; 354 } 355 356 /* 357 * On output, if we have either of the 358 * source routing options, we should 359 * swap the destination address of the 360 * IP header with the last address 361 * specified in the option, as that is 362 * what the destination's IP header 363 * will look like. 364 */ 365 if (out) 366 bcopy(ptr + off + ptr[off + 1] - 367 sizeof(struct in_addr), 368 &(ip->ip_dst), sizeof(struct in_addr)); 369 370 /* Fall through */ 371 default: 372 /* Sanity check for option length. */ 373 if (ptr[off + 1] < 2) { 374 DPRINTF(("%s: illegal IPv4 option " 375 "length for option %d\n", 376 __func__, ptr[off])); 377 m_freem(m); 378 return EINVAL; 379 } 380 381 /* Zeroize all other options. */ 382 count = ptr[off + 1]; 383 bcopy(ipseczeroes, ptr + off, count); 384 off += count; 385 break; 386 } 387 388 /* Sanity check. */ 389 if (off > skip) { 390 DPRINTF(("%s: malformed IPv4 options header\n", 391 __func__)); 392 393 m_freem(m); 394 return EINVAL; 395 } 396 } 397 398 break; 399 #endif /* INET */ 400 401 #ifdef INET6 402 case AF_INET6: /* Ugly... */ 403 /* Copy and "cook" the IPv6 header. */ 404 m_copydata(m, 0, sizeof(ip6), (caddr_t) &ip6); 405 406 /* We don't do IPv6 Jumbograms. */ 407 if (ip6.ip6_plen == 0) { 408 DPRINTF(("%s: unsupported IPv6 jumbogram\n", __func__)); 409 m_freem(m); 410 return EMSGSIZE; 411 } 412 413 ip6.ip6_flow = 0; 414 ip6.ip6_hlim = 0; 415 ip6.ip6_vfc &= ~IPV6_VERSION_MASK; 416 ip6.ip6_vfc |= IPV6_VERSION; 417 418 /* Scoped address handling. */ 419 if (IN6_IS_SCOPE_LINKLOCAL(&ip6.ip6_src)) 420 ip6.ip6_src.s6_addr16[1] = 0; 421 if (IN6_IS_SCOPE_LINKLOCAL(&ip6.ip6_dst)) 422 ip6.ip6_dst.s6_addr16[1] = 0; 423 424 /* Done with IPv6 header. */ 425 m_copyback(m, 0, sizeof(struct ip6_hdr), (caddr_t) &ip6); 426 427 /* Let's deal with the remaining headers (if any). */ 428 if (skip - sizeof(struct ip6_hdr) > 0) { 429 if (m->m_len <= skip) { 430 ptr = (unsigned char *) malloc( 431 skip - sizeof(struct ip6_hdr), 432 M_AH, M_NOWAIT); 433 if (ptr == NULL) { 434 DPRINTF(("%s: failed to allocate memory" 435 "for IPv6 headers\n",__func__)); 436 m_freem(m); 437 return ENOBUFS; 438 } 439 440 /* 441 * Copy all the protocol headers after 442 * the IPv6 header. 443 */ 444 m_copydata(m, sizeof(struct ip6_hdr), 445 skip - sizeof(struct ip6_hdr), ptr); 446 alloc = 1; 447 } else { 448 /* No need to allocate memory. */ 449 ptr = mtod(m, unsigned char *) + 450 sizeof(struct ip6_hdr); 451 alloc = 0; 452 } 453 } else 454 break; 455 456 nxt = ip6.ip6_nxt & 0xff; /* Next header type. */ 457 458 for (off = 0; off < skip - sizeof(struct ip6_hdr);) 459 switch (nxt) { 460 case IPPROTO_HOPOPTS: 461 case IPPROTO_DSTOPTS: 462 ip6e = (struct ip6_ext *)(ptr + off); 463 noff = off + ((ip6e->ip6e_len + 1) << 3); 464 465 /* Sanity check. */ 466 if (noff > skip - sizeof(struct ip6_hdr)) 467 goto error6; 468 469 /* 470 * Zero out mutable options. 471 */ 472 for (count = off + sizeof(struct ip6_ext); 473 count < noff;) { 474 if (ptr[count] == IP6OPT_PAD1) { 475 count++; 476 continue; /* Skip padding. */ 477 } 478 479 ad = ptr[count + 1] + 2; 480 if (count + ad > noff) 481 goto error6; 482 483 if (ptr[count] & IP6OPT_MUTABLE) 484 memset(ptr + count, 0, ad); 485 count += ad; 486 } 487 488 if (count != noff) 489 goto error6; 490 491 /* Advance. */ 492 off += ((ip6e->ip6e_len + 1) << 3); 493 nxt = ip6e->ip6e_nxt; 494 break; 495 496 case IPPROTO_ROUTING: 497 /* 498 * Always include routing headers in 499 * computation. 500 */ 501 ip6e = (struct ip6_ext *) (ptr + off); 502 off += ((ip6e->ip6e_len + 1) << 3); 503 nxt = ip6e->ip6e_nxt; 504 break; 505 506 default: 507 DPRINTF(("%s: unexpected IPv6 header type %d", 508 __func__, off)); 509 error6: 510 if (alloc) 511 free(ptr, M_AH); 512 m_freem(m); 513 return EINVAL; 514 } 515 516 /* Copyback and free, if we allocated. */ 517 if (alloc) { 518 m_copyback(m, sizeof(struct ip6_hdr), 519 skip - sizeof(struct ip6_hdr), ptr); 520 free(ptr, M_AH); 521 } 522 523 break; 524 #endif /* INET6 */ 525 } 526 527 return 0; 528 } 529 530 /* 531 * ah_input() gets called to verify that an input packet 532 * passes authentication. 533 */ 534 static int 535 ah_input(struct mbuf *m, struct secasvar *sav, int skip, int protoff) 536 { 537 IPSEC_DEBUG_DECLARE(char buf[128]); 538 const struct auth_hash *ahx; 539 struct cryptop *crp; 540 struct xform_data *xd; 541 struct newah *ah; 542 crypto_session_t cryptoid; 543 int hl, rplen, authsize, ahsize, error; 544 uint32_t seqh; 545 546 SECASVAR_RLOCK_TRACKER; 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_RLOCK(sav); 569 if (sav->replay != NULL && sav->replay->wsize != 0 && 570 ipsec_chkreplay(ntohl(ah->ah_seq), &seqh, sav) == 0) { 571 SECASVAR_RUNLOCK(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_RUNLOCK(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_AH, 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_AH); 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 crypto_use_mbuf(crp, m); 661 crp->crp_callback = ah_input_cb; 662 crp->crp_opaque = xd; 663 664 if (sav->flags & SADB_X_SAFLAGS_ESN && 665 sav->replay != NULL && sav->replay->wsize != 0) { 666 seqh = htonl(seqh); 667 memcpy(crp->crp_esn, &seqh, sizeof(seqh)); 668 } 669 670 /* These are passed as-is to the callback. */ 671 xd->sav = sav; 672 xd->nxt = hl; 673 xd->protoff = protoff; 674 xd->skip = skip; 675 xd->cryptoid = cryptoid; 676 xd->vnet = curvnet; 677 if (V_async_crypto) 678 return (crypto_dispatch_async(crp, CRYPTO_ASYNC_ORDERED)); 679 else 680 return (crypto_dispatch(crp)); 681 bad: 682 m_freem(m); 683 key_freesav(&sav); 684 return (error); 685 } 686 687 /* 688 * AH input callback from the crypto driver. 689 */ 690 static int 691 ah_input_cb(struct cryptop *crp) 692 { 693 IPSEC_DEBUG_DECLARE(char buf[IPSEC_ADDRSTRLEN]); 694 unsigned char calc[AH_ALEN_MAX]; 695 struct mbuf *m; 696 struct xform_data *xd; 697 struct secasvar *sav; 698 struct secasindex *saidx; 699 caddr_t ptr; 700 crypto_session_t cryptoid; 701 int authsize, rplen, ahsize, error, skip, protoff; 702 uint8_t nxt; 703 704 SECASVAR_RLOCK_TRACKER; 705 706 m = crp->crp_buf.cb_mbuf; 707 xd = 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_session, &cryptoid) != 0) 724 crypto_freesession(cryptoid); 725 xd->cryptoid = crp->crp_session; 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_AH), 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_RLOCK(sav); 787 if (ipsec_updatereplay(ntohl(seq), sav)) { 788 SECASVAR_RUNLOCK(sav); 789 AHSTAT_INC(ahs_replay); 790 error = EACCES; 791 goto bad; 792 } 793 SECASVAR_RUNLOCK(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_AH); 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 xform_data *xd; 848 struct mbuf *mi; 849 struct cryptop *crp; 850 struct newah *ah; 851 crypto_session_t cryptoid; 852 uint16_t iplen; 853 int error, rplen, authsize, ahsize, maxpacketsize, roff; 854 uint8_t prot; 855 uint32_t seqh; 856 857 SECASVAR_RLOCK_TRACKER; 858 859 IPSEC_ASSERT(sav != NULL, ("null SA")); 860 ahx = sav->tdb_authalgxform; 861 IPSEC_ASSERT(ahx != NULL, ("null authentication xform")); 862 863 AHSTAT_INC(ahs_output); 864 865 /* Figure out header size. */ 866 rplen = HDRSIZE(sav); 867 authsize = AUTHSIZE(sav); 868 ahsize = ah_hdrsiz(sav); 869 870 /* Check for maximum packet size violations. */ 871 switch (sav->sah->saidx.dst.sa.sa_family) { 872 #ifdef INET 873 case AF_INET: 874 maxpacketsize = IP_MAXPACKET; 875 break; 876 #endif /* INET */ 877 #ifdef INET6 878 case AF_INET6: 879 maxpacketsize = IPV6_MAXPACKET; 880 break; 881 #endif /* INET6 */ 882 default: 883 DPRINTF(("%s: unknown/unsupported protocol family %u, " 884 "SA %s/%08lx\n", __func__, 885 sav->sah->saidx.dst.sa.sa_family, 886 ipsec_address(&sav->sah->saidx.dst, buf, sizeof(buf)), 887 (u_long) ntohl(sav->spi))); 888 AHSTAT_INC(ahs_nopf); 889 error = EPFNOSUPPORT; 890 goto bad; 891 } 892 if (ahsize + m->m_pkthdr.len > maxpacketsize) { 893 DPRINTF(("%s: packet in SA %s/%08lx got too big " 894 "(len %u, max len %u)\n", __func__, 895 ipsec_address(&sav->sah->saidx.dst, buf, sizeof(buf)), 896 (u_long) ntohl(sav->spi), 897 ahsize + m->m_pkthdr.len, maxpacketsize)); 898 AHSTAT_INC(ahs_toobig); 899 error = EMSGSIZE; 900 goto bad; 901 } 902 903 /* Update the counters. */ 904 AHSTAT_ADD(ahs_obytes, m->m_pkthdr.len - skip); 905 906 m = m_unshare(m, M_NOWAIT); 907 if (m == NULL) { 908 DPRINTF(("%s: cannot clone mbuf chain, SA %s/%08lx\n", __func__, 909 ipsec_address(&sav->sah->saidx.dst, buf, sizeof(buf)), 910 (u_long) ntohl(sav->spi))); 911 AHSTAT_INC(ahs_hdrops); 912 error = ENOBUFS; 913 goto bad; 914 } 915 916 /* Inject AH header. */ 917 mi = m_makespace(m, skip, ahsize, &roff); 918 if (mi == NULL) { 919 DPRINTF(("%s: failed to inject %u byte AH header for SA " 920 "%s/%08lx\n", __func__, ahsize, 921 ipsec_address(&sav->sah->saidx.dst, buf, sizeof(buf)), 922 (u_long) ntohl(sav->spi))); 923 AHSTAT_INC(ahs_hdrops); /*XXX differs from openbsd */ 924 error = ENOBUFS; 925 goto bad; 926 } 927 928 /* 929 * The AH header is guaranteed by m_makespace() to be in 930 * contiguous memory, at roff bytes offset into the returned mbuf. 931 */ 932 ah = (struct newah *)(mtod(mi, caddr_t) + roff); 933 934 /* Initialize the AH header. */ 935 m_copydata(m, protoff, sizeof(u_int8_t), (caddr_t) &ah->ah_nxt); 936 ah->ah_len = (ahsize - sizeof(struct ah)) / sizeof(u_int32_t); 937 ah->ah_reserve = 0; 938 ah->ah_spi = sav->spi; 939 940 /* Zeroize authenticator. */ 941 m_copyback(m, skip + rplen, authsize, ipseczeroes); 942 943 /* Zeroize padding */ 944 m_copyback(m, skip + rplen + authsize, ahsize - (rplen + authsize), 945 ipseczeroes); 946 947 /* Insert packet replay counter, as requested. */ 948 SECASVAR_RLOCK(sav); 949 if (sav->replay) { 950 SECREPLAY_LOCK(sav->replay); 951 if ((sav->replay->count == ~0 || 952 (!(sav->flags & SADB_X_SAFLAGS_ESN) && 953 ((uint32_t)sav->replay->count) == ~0)) && 954 (sav->flags & SADB_X_EXT_CYCSEQ) == 0) { 955 SECREPLAY_UNLOCK(sav->replay); 956 SECASVAR_RUNLOCK(sav); 957 DPRINTF(("%s: replay counter wrapped for SA %s/%08lx\n", 958 __func__, ipsec_address(&sav->sah->saidx.dst, buf, 959 sizeof(buf)), (u_long) ntohl(sav->spi))); 960 AHSTAT_INC(ahs_wrap); 961 error = EACCES; 962 goto bad; 963 } 964 #ifdef REGRESSION 965 /* Emulate replay attack when ipsec_replay is TRUE. */ 966 if (!V_ipsec_replay) 967 #endif 968 sav->replay->count++; 969 ah->ah_seq = htonl((uint32_t)sav->replay->count); 970 SECREPLAY_UNLOCK(sav->replay); 971 } 972 cryptoid = sav->tdb_cryptoid; 973 SECASVAR_RUNLOCK(sav); 974 975 /* Get crypto descriptors. */ 976 crp = crypto_getreq(cryptoid, M_NOWAIT); 977 if (crp == NULL) { 978 DPRINTF(("%s: failed to acquire crypto descriptors\n", 979 __func__)); 980 AHSTAT_INC(ahs_crypto); 981 error = ENOBUFS; 982 goto bad; 983 } 984 985 crp->crp_payload_start = 0; 986 crp->crp_payload_length = m->m_pkthdr.len; 987 crp->crp_digest_start = skip + rplen; 988 989 /* Allocate IPsec-specific opaque crypto info. */ 990 xd = malloc(sizeof(struct xform_data) + skip, M_AH, 991 M_NOWAIT | M_ZERO); 992 if (xd == NULL) { 993 crypto_freereq(crp); 994 DPRINTF(("%s: failed to allocate xform_data\n", __func__)); 995 AHSTAT_INC(ahs_crypto); 996 error = ENOBUFS; 997 goto bad; 998 } 999 1000 /* Save the skipped portion of the packet. */ 1001 m_copydata(m, 0, skip, (caddr_t) (xd + 1)); 1002 1003 /* 1004 * Fix IP header length on the header used for 1005 * authentication. We don't need to fix the original 1006 * header length as it will be fixed by our caller. 1007 */ 1008 switch (sav->sah->saidx.dst.sa.sa_family) { 1009 #ifdef INET 1010 case AF_INET: 1011 bcopy(((caddr_t)(xd + 1)) + 1012 offsetof(struct ip, ip_len), 1013 (caddr_t) &iplen, sizeof(u_int16_t)); 1014 iplen = htons(ntohs(iplen) + ahsize); 1015 m_copyback(m, offsetof(struct ip, ip_len), 1016 sizeof(u_int16_t), (caddr_t) &iplen); 1017 break; 1018 #endif /* INET */ 1019 1020 #ifdef INET6 1021 case AF_INET6: 1022 bcopy(((caddr_t)(xd + 1)) + 1023 offsetof(struct ip6_hdr, ip6_plen), 1024 (caddr_t) &iplen, sizeof(uint16_t)); 1025 iplen = htons(ntohs(iplen) + ahsize); 1026 m_copyback(m, offsetof(struct ip6_hdr, ip6_plen), 1027 sizeof(uint16_t), (caddr_t) &iplen); 1028 break; 1029 #endif /* INET6 */ 1030 } 1031 1032 /* Fix the Next Header field in saved header. */ 1033 ((uint8_t *) (xd + 1))[protoff] = IPPROTO_AH; 1034 1035 /* Update the Next Protocol field in the IP header. */ 1036 prot = IPPROTO_AH; 1037 m_copyback(m, protoff, sizeof(uint8_t), (caddr_t) &prot); 1038 1039 /* "Massage" the packet headers for crypto processing. */ 1040 error = ah_massage_headers(&m, sav->sah->saidx.dst.sa.sa_family, 1041 skip, ahx->type, 1); 1042 if (error != 0) { 1043 m = NULL; /* mbuf was free'd by ah_massage_headers. */ 1044 free(xd, M_AH); 1045 crypto_freereq(crp); 1046 goto bad; 1047 } 1048 1049 /* Crypto operation descriptor. */ 1050 crp->crp_op = CRYPTO_OP_COMPUTE_DIGEST; 1051 crp->crp_flags = CRYPTO_F_CBIFSYNC; 1052 crypto_use_mbuf(crp, m); 1053 crp->crp_callback = ah_output_cb; 1054 crp->crp_opaque = xd; 1055 1056 if (sav->flags & SADB_X_SAFLAGS_ESN && sav->replay != NULL) { 1057 SECREPLAY_LOCK(sav->replay); 1058 seqh = htonl((uint32_t)(sav->replay->count >> IPSEC_SEQH_SHIFT)); 1059 memcpy(crp->crp_esn, &seqh, sizeof(seqh)); 1060 SECREPLAY_UNLOCK(sav->replay); 1061 } 1062 1063 /* These are passed as-is to the callback. */ 1064 xd->sp = sp; 1065 xd->sav = sav; 1066 xd->skip = skip; 1067 xd->idx = idx; 1068 xd->cryptoid = cryptoid; 1069 xd->vnet = curvnet; 1070 1071 if (V_async_crypto) 1072 return (crypto_dispatch_async(crp, CRYPTO_ASYNC_ORDERED)); 1073 else 1074 return (crypto_dispatch(crp)); 1075 bad: 1076 if (m) 1077 m_freem(m); 1078 key_freesav(&sav); 1079 key_freesp(&sp); 1080 return (error); 1081 } 1082 1083 /* 1084 * AH output callback from the crypto driver. 1085 */ 1086 static int 1087 ah_output_cb(struct cryptop *crp) 1088 { 1089 struct xform_data *xd; 1090 struct secpolicy *sp; 1091 struct secasvar *sav; 1092 struct mbuf *m; 1093 crypto_session_t cryptoid; 1094 caddr_t ptr; 1095 u_int idx; 1096 int skip, error; 1097 1098 m = crp->crp_buf.cb_mbuf; 1099 xd = (struct xform_data *) crp->crp_opaque; 1100 CURVNET_SET(xd->vnet); 1101 sp = xd->sp; 1102 sav = xd->sav; 1103 skip = xd->skip; 1104 idx = xd->idx; 1105 cryptoid = xd->cryptoid; 1106 ptr = (caddr_t) (xd + 1); 1107 1108 /* Check for crypto errors. */ 1109 if (crp->crp_etype) { 1110 if (crp->crp_etype == EAGAIN) { 1111 /* Reset the session ID */ 1112 if (ipsec_updateid(sav, &crp->crp_session, &cryptoid) != 0) 1113 crypto_freesession(cryptoid); 1114 xd->cryptoid = crp->crp_session; 1115 CURVNET_RESTORE(); 1116 return (crypto_dispatch(crp)); 1117 } 1118 AHSTAT_INC(ahs_noxform); 1119 DPRINTF(("%s: crypto error %d\n", __func__, crp->crp_etype)); 1120 error = crp->crp_etype; 1121 m_freem(m); 1122 goto bad; 1123 } 1124 1125 /* Shouldn't happen... */ 1126 if (m == NULL) { 1127 AHSTAT_INC(ahs_crypto); 1128 DPRINTF(("%s: bogus returned buffer from crypto\n", __func__)); 1129 error = EINVAL; 1130 goto bad; 1131 } 1132 /* 1133 * Copy original headers (with the new protocol number) back 1134 * in place. 1135 */ 1136 m_copyback(m, 0, skip, ptr); 1137 1138 free(xd, M_AH); 1139 crypto_freereq(crp); 1140 AHSTAT_INC(ahs_hist[sav->alg_auth]); 1141 #ifdef REGRESSION 1142 /* Emulate man-in-the-middle attack when ipsec_integrity is TRUE. */ 1143 if (V_ipsec_integrity) { 1144 int alen; 1145 1146 /* 1147 * Corrupt HMAC if we want to test integrity verification of 1148 * the other side. 1149 */ 1150 alen = AUTHSIZE(sav); 1151 m_copyback(m, m->m_pkthdr.len - alen, alen, ipseczeroes); 1152 } 1153 #endif 1154 1155 /* NB: m is reclaimed by ipsec_process_done. */ 1156 error = ipsec_process_done(m, sp, sav, idx); 1157 CURVNET_RESTORE(); 1158 return (error); 1159 bad: 1160 CURVNET_RESTORE(); 1161 free(xd, M_AH); 1162 crypto_freereq(crp); 1163 key_freesav(&sav); 1164 key_freesp(&sp); 1165 return (error); 1166 } 1167 1168 static struct xformsw ah_xformsw = { 1169 .xf_type = XF_AH, 1170 .xf_name = "IPsec AH", 1171 .xf_init = ah_init, 1172 .xf_cleanup = ah_cleanup, 1173 .xf_input = ah_input, 1174 .xf_output = ah_output, 1175 }; 1176 1177 SYSINIT(ah_xform_init, SI_SUB_PROTO_DOMAIN, SI_ORDER_MIDDLE, 1178 xform_attach, &ah_xformsw); 1179 SYSUNINIT(ah_xform_uninit, SI_SUB_PROTO_DOMAIN, SI_ORDER_MIDDLE, 1180 xform_detach, &ah_xformsw); 1181