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/malloc.h> 46 #include <sys/mbuf.h> 47 #include <sys/socket.h> 48 #include <sys/syslog.h> 49 #include <sys/kernel.h> 50 #include <sys/lock.h> 51 #include <sys/mutex.h> 52 #include <sys/sysctl.h> 53 54 #include <net/if.h> 55 #include <net/vnet.h> 56 57 #include <netinet/in.h> 58 #include <netinet/in_systm.h> 59 #include <netinet/ip.h> 60 #include <netinet/ip_ecn.h> 61 #include <netinet/ip6.h> 62 63 #include <netipsec/ipsec.h> 64 #include <netipsec/ah.h> 65 #include <netipsec/ah_var.h> 66 #include <netipsec/xform.h> 67 68 #ifdef INET6 69 #include <netinet6/ip6_var.h> 70 #include <netipsec/ipsec6.h> 71 #include <netinet6/ip6_ecn.h> 72 #endif 73 74 #include <netipsec/key.h> 75 #include <netipsec/key_debug.h> 76 77 #include <opencrypto/cryptodev.h> 78 79 /* 80 * Return header size in bytes. The old protocol did not support 81 * the replay counter; the new protocol always includes the counter. 82 */ 83 #define HDRSIZE(sav) \ 84 (((sav)->flags & SADB_X_EXT_OLD) ? \ 85 sizeof (struct ah) : sizeof (struct ah) + sizeof (u_int32_t)) 86 /* 87 * Return authenticator size in bytes, based on a field in the 88 * algorithm descriptor. 89 */ 90 #define AUTHSIZE(sav) ((sav->flags & SADB_X_EXT_OLD) ? 16 : \ 91 xform_ah_authsize((sav)->tdb_authalgxform)) 92 93 VNET_DEFINE(int, ah_enable) = 1; /* control flow of packets with AH */ 94 VNET_DEFINE(int, ah_cleartos) = 1; /* clear ip_tos when doing AH calc */ 95 VNET_PCPUSTAT_DEFINE(struct ahstat, ahstat); 96 VNET_PCPUSTAT_SYSINIT(ahstat); 97 98 #ifdef VIMAGE 99 VNET_PCPUSTAT_SYSUNINIT(ahstat); 100 #endif /* VIMAGE */ 101 102 #ifdef INET 103 SYSCTL_DECL(_net_inet_ah); 104 SYSCTL_INT(_net_inet_ah, OID_AUTO, ah_enable, 105 CTLFLAG_VNET | CTLFLAG_RW, &VNET_NAME(ah_enable), 0, ""); 106 SYSCTL_INT(_net_inet_ah, OID_AUTO, ah_cleartos, 107 CTLFLAG_VNET | CTLFLAG_RW, &VNET_NAME(ah_cleartos), 0, ""); 108 SYSCTL_VNET_PCPUSTAT(_net_inet_ah, IPSECCTL_STATS, stats, struct ahstat, 109 ahstat, "AH statistics (struct ahstat, netipsec/ah_var.h)"); 110 #endif 111 112 static MALLOC_DEFINE(M_AH, "ah", "IPsec AH"); 113 114 static unsigned char ipseczeroes[256]; /* larger than an ip6 extension hdr */ 115 116 static int ah_input_cb(struct cryptop*); 117 static int ah_output_cb(struct cryptop*); 118 119 int 120 xform_ah_authsize(const struct auth_hash *esph) 121 { 122 int alen; 123 124 if (esph == NULL) 125 return 0; 126 127 switch (esph->type) { 128 case CRYPTO_SHA2_256_HMAC: 129 case CRYPTO_SHA2_384_HMAC: 130 case CRYPTO_SHA2_512_HMAC: 131 alen = esph->hashsize / 2; /* RFC4868 2.3 */ 132 break; 133 134 case CRYPTO_POLY1305: 135 case CRYPTO_AES_NIST_GMAC: 136 alen = esph->hashsize; 137 break; 138 139 default: 140 alen = AH_HMAC_HASHLEN; 141 break; 142 } 143 144 return alen; 145 } 146 147 size_t 148 ah_hdrsiz(struct secasvar *sav) 149 { 150 size_t size; 151 152 if (sav != NULL) { 153 int authsize, rplen, align; 154 155 IPSEC_ASSERT(sav->tdb_authalgxform != NULL, ("null xform")); 156 /*XXX not right for null algorithm--does it matter??*/ 157 158 /* RFC4302: use the correct alignment. */ 159 align = sizeof(uint32_t); 160 #ifdef INET6 161 if (sav->sah->saidx.dst.sa.sa_family == AF_INET6) { 162 align = sizeof(uint64_t); 163 } 164 #endif 165 rplen = HDRSIZE(sav); 166 authsize = AUTHSIZE(sav); 167 size = roundup(rplen + authsize, align); 168 } else { 169 /* default guess */ 170 size = sizeof (struct ah) + sizeof (u_int32_t) + 16; 171 } 172 return size; 173 } 174 175 /* 176 * NB: public for use by esp_init. 177 */ 178 int 179 ah_init0(struct secasvar *sav, struct xformsw *xsp, 180 struct crypto_session_params *csp) 181 { 182 const struct auth_hash *thash; 183 int keylen; 184 185 thash = auth_algorithm_lookup(sav->alg_auth); 186 if (thash == NULL) { 187 DPRINTF(("%s: unsupported authentication algorithm %u\n", 188 __func__, sav->alg_auth)); 189 return EINVAL; 190 } 191 192 /* 193 * Verify the replay state block allocation is consistent with 194 * the protocol type. We check here so we can make assumptions 195 * later during protocol processing. 196 */ 197 /* NB: replay state is setup elsewhere (sigh) */ 198 if (((sav->flags&SADB_X_EXT_OLD) == 0) ^ (sav->replay != NULL)) { 199 DPRINTF(("%s: replay state block inconsistency, " 200 "%s algorithm %s replay state\n", __func__, 201 (sav->flags & SADB_X_EXT_OLD) ? "old" : "new", 202 sav->replay == NULL ? "without" : "with")); 203 return EINVAL; 204 } 205 if (sav->key_auth == NULL) { 206 DPRINTF(("%s: no authentication key for %s algorithm\n", 207 __func__, thash->name)); 208 return EINVAL; 209 } 210 keylen = _KEYLEN(sav->key_auth); 211 if (keylen > thash->keysize && thash->keysize != 0) { 212 DPRINTF(("%s: invalid keylength %d, algorithm %s requires " 213 "keysize less than %d\n", __func__, 214 keylen, thash->name, thash->keysize)); 215 return EINVAL; 216 } 217 218 sav->tdb_xform = xsp; 219 sav->tdb_authalgxform = thash; 220 221 /* Initialize crypto session. */ 222 csp->csp_auth_alg = sav->tdb_authalgxform->type; 223 if (csp->csp_auth_alg != CRYPTO_NULL_HMAC) { 224 csp->csp_auth_klen = _KEYBITS(sav->key_auth) / 8; 225 csp->csp_auth_key = sav->key_auth->key_data; 226 }; 227 csp->csp_auth_mlen = AUTHSIZE(sav); 228 229 return 0; 230 } 231 232 /* 233 * ah_init() is called when an SPI is being set up. 234 */ 235 static int 236 ah_init(struct secasvar *sav, struct xformsw *xsp) 237 { 238 struct crypto_session_params csp; 239 int error; 240 241 memset(&csp, 0, sizeof(csp)); 242 csp.csp_mode = CSP_MODE_DIGEST; 243 244 if (sav->flags & SADB_X_SAFLAGS_ESN) 245 csp.csp_flags |= CSP_F_ESN; 246 247 error = ah_init0(sav, xsp, &csp); 248 return error ? error : 249 crypto_newsession(&sav->tdb_cryptoid, &csp, V_crypto_support); 250 } 251 252 static void 253 ah_cleanup(struct secasvar *sav) 254 { 255 256 crypto_freesession(sav->tdb_cryptoid); 257 sav->tdb_cryptoid = NULL; 258 sav->tdb_authalgxform = NULL; 259 } 260 261 /* 262 * Massage IPv4/IPv6 headers for AH processing. 263 */ 264 static int 265 ah_massage_headers(struct mbuf **m0, int proto, int skip, int alg, int out) 266 { 267 struct mbuf *m = *m0; 268 unsigned char *ptr; 269 int off, count; 270 271 #ifdef INET 272 struct ip *ip; 273 #endif /* INET */ 274 275 #ifdef INET6 276 struct ip6_ext *ip6e; 277 struct ip6_hdr ip6; 278 int ad, alloc, nxt, noff; 279 #endif /* INET6 */ 280 281 switch (proto) { 282 #ifdef INET 283 case AF_INET: 284 /* 285 * This is the least painful way of dealing with IPv4 header 286 * and option processing -- just make sure they're in 287 * contiguous memory. 288 */ 289 *m0 = m = m_pullup(m, skip); 290 if (m == NULL) { 291 DPRINTF(("%s: m_pullup failed\n", __func__)); 292 return ENOBUFS; 293 } 294 295 /* Fix the IP header */ 296 ip = mtod(m, struct ip *); 297 if (V_ah_cleartos) 298 ip->ip_tos = 0; 299 ip->ip_ttl = 0; 300 ip->ip_sum = 0; 301 ip->ip_off = htons(0); 302 303 ptr = mtod(m, unsigned char *); 304 305 /* IPv4 option processing */ 306 for (off = sizeof(struct ip); off < skip;) { 307 if (ptr[off] == IPOPT_EOL || ptr[off] == IPOPT_NOP || 308 off + 1 < skip) 309 ; 310 else { 311 DPRINTF(("%s: illegal IPv4 option length for " 312 "option %d\n", __func__, ptr[off])); 313 314 m_freem(m); 315 return EINVAL; 316 } 317 318 switch (ptr[off]) { 319 case IPOPT_EOL: 320 off = skip; /* End the loop. */ 321 break; 322 323 case IPOPT_NOP: 324 off++; 325 break; 326 327 case IPOPT_SECURITY: /* 0x82 */ 328 case 0x85: /* Extended security. */ 329 case 0x86: /* Commercial security. */ 330 case 0x94: /* Router alert */ 331 case 0x95: /* RFC1770 */ 332 /* Sanity check for option length. */ 333 if (ptr[off + 1] < 2) { 334 DPRINTF(("%s: illegal IPv4 option " 335 "length for option %d\n", 336 __func__, ptr[off])); 337 338 m_freem(m); 339 return EINVAL; 340 } 341 342 off += ptr[off + 1]; 343 break; 344 345 case IPOPT_LSRR: 346 case IPOPT_SSRR: 347 /* Sanity check for option length. */ 348 if (ptr[off + 1] < 2) { 349 DPRINTF(("%s: illegal IPv4 option " 350 "length for option %d\n", 351 __func__, ptr[off])); 352 353 m_freem(m); 354 return EINVAL; 355 } 356 357 /* 358 * On output, if we have either of the 359 * source routing options, we should 360 * swap the destination address of the 361 * IP header with the last address 362 * specified in the option, as that is 363 * what the destination's IP header 364 * will look like. 365 */ 366 if (out) 367 bcopy(ptr + off + ptr[off + 1] - 368 sizeof(struct in_addr), 369 &(ip->ip_dst), sizeof(struct in_addr)); 370 371 /* Fall through */ 372 default: 373 /* Sanity check for option length. */ 374 if (ptr[off + 1] < 2) { 375 DPRINTF(("%s: illegal IPv4 option " 376 "length for option %d\n", 377 __func__, ptr[off])); 378 m_freem(m); 379 return EINVAL; 380 } 381 382 /* Zeroize all other options. */ 383 count = ptr[off + 1]; 384 bcopy(ipseczeroes, ptr + off, count); 385 off += count; 386 break; 387 } 388 389 /* Sanity check. */ 390 if (off > skip) { 391 DPRINTF(("%s: malformed IPv4 options header\n", 392 __func__)); 393 394 m_freem(m); 395 return EINVAL; 396 } 397 } 398 399 break; 400 #endif /* INET */ 401 402 #ifdef INET6 403 case AF_INET6: /* Ugly... */ 404 /* Copy and "cook" the IPv6 header. */ 405 m_copydata(m, 0, sizeof(ip6), (caddr_t) &ip6); 406 407 /* We don't do IPv6 Jumbograms. */ 408 if (ip6.ip6_plen == 0) { 409 DPRINTF(("%s: unsupported IPv6 jumbogram\n", __func__)); 410 m_freem(m); 411 return EMSGSIZE; 412 } 413 414 ip6.ip6_flow = 0; 415 ip6.ip6_hlim = 0; 416 ip6.ip6_vfc &= ~IPV6_VERSION_MASK; 417 ip6.ip6_vfc |= IPV6_VERSION; 418 419 /* Scoped address handling. */ 420 if (IN6_IS_SCOPE_LINKLOCAL(&ip6.ip6_src)) 421 ip6.ip6_src.s6_addr16[1] = 0; 422 if (IN6_IS_SCOPE_LINKLOCAL(&ip6.ip6_dst)) 423 ip6.ip6_dst.s6_addr16[1] = 0; 424 425 /* Done with IPv6 header. */ 426 m_copyback(m, 0, sizeof(struct ip6_hdr), (caddr_t) &ip6); 427 428 /* Let's deal with the remaining headers (if any). */ 429 if (skip - sizeof(struct ip6_hdr) > 0) { 430 if (m->m_len <= skip) { 431 ptr = (unsigned char *) malloc( 432 skip - sizeof(struct ip6_hdr), 433 M_AH, M_NOWAIT); 434 if (ptr == NULL) { 435 DPRINTF(("%s: failed to allocate memory" 436 "for IPv6 headers\n",__func__)); 437 m_freem(m); 438 return ENOBUFS; 439 } 440 441 /* 442 * Copy all the protocol headers after 443 * the IPv6 header. 444 */ 445 m_copydata(m, sizeof(struct ip6_hdr), 446 skip - sizeof(struct ip6_hdr), ptr); 447 alloc = 1; 448 } else { 449 /* No need to allocate memory. */ 450 ptr = mtod(m, unsigned char *) + 451 sizeof(struct ip6_hdr); 452 alloc = 0; 453 } 454 } else 455 break; 456 457 nxt = ip6.ip6_nxt & 0xff; /* Next header type. */ 458 459 for (off = 0; off < skip - sizeof(struct ip6_hdr);) 460 switch (nxt) { 461 case IPPROTO_HOPOPTS: 462 case IPPROTO_DSTOPTS: 463 ip6e = (struct ip6_ext *)(ptr + off); 464 noff = off + ((ip6e->ip6e_len + 1) << 3); 465 466 /* Sanity check. */ 467 if (noff > skip - sizeof(struct ip6_hdr)) 468 goto error6; 469 470 /* 471 * Zero out mutable options. 472 */ 473 for (count = off + sizeof(struct ip6_ext); 474 count < noff;) { 475 if (ptr[count] == IP6OPT_PAD1) { 476 count++; 477 continue; /* Skip padding. */ 478 } 479 480 ad = ptr[count + 1] + 2; 481 if (count + ad > noff) 482 goto error6; 483 484 if (ptr[count] & IP6OPT_MUTABLE) 485 memset(ptr + count, 0, ad); 486 count += ad; 487 } 488 489 if (count != noff) 490 goto error6; 491 492 /* Advance. */ 493 off += ((ip6e->ip6e_len + 1) << 3); 494 nxt = ip6e->ip6e_nxt; 495 break; 496 497 case IPPROTO_ROUTING: 498 /* 499 * Always include routing headers in 500 * computation. 501 */ 502 ip6e = (struct ip6_ext *) (ptr + off); 503 off += ((ip6e->ip6e_len + 1) << 3); 504 nxt = ip6e->ip6e_nxt; 505 break; 506 507 default: 508 DPRINTF(("%s: unexpected IPv6 header type %d", 509 __func__, off)); 510 error6: 511 if (alloc) 512 free(ptr, M_AH); 513 m_freem(m); 514 return EINVAL; 515 } 516 517 /* Copyback and free, if we allocated. */ 518 if (alloc) { 519 m_copyback(m, sizeof(struct ip6_hdr), 520 skip - sizeof(struct ip6_hdr), ptr); 521 free(ptr, M_AH); 522 } 523 524 break; 525 #endif /* INET6 */ 526 } 527 528 return 0; 529 } 530 531 /* 532 * ah_input() gets called to verify that an input packet 533 * passes authentication. 534 */ 535 static int 536 ah_input(struct mbuf *m, struct secasvar *sav, int skip, int protoff) 537 { 538 IPSEC_DEBUG_DECLARE(char buf[128]); 539 const struct auth_hash *ahx; 540 struct cryptop *crp; 541 struct xform_data *xd; 542 struct newah *ah; 543 crypto_session_t cryptoid; 544 int hl, rplen, authsize, ahsize, error; 545 uint32_t seqh; 546 547 SECASVAR_RLOCK_TRACKER; 548 549 IPSEC_ASSERT(sav != NULL, ("null SA")); 550 IPSEC_ASSERT(sav->key_auth != NULL, ("null authentication key")); 551 IPSEC_ASSERT(sav->tdb_authalgxform != NULL, 552 ("null authentication xform")); 553 554 /* Figure out header size. */ 555 rplen = HDRSIZE(sav); 556 557 if (m->m_len < skip + rplen) { 558 m = m_pullup(m, skip + rplen); 559 if (m == NULL) { 560 DPRINTF(("ah_input: cannot pullup header\n")); 561 AHSTAT_INC(ahs_hdrops); /*XXX*/ 562 error = ENOBUFS; 563 goto bad; 564 } 565 } 566 ah = (struct newah *)(mtod(m, caddr_t) + skip); 567 568 /* Check replay window, if applicable. */ 569 SECASVAR_RLOCK(sav); 570 if (sav->replay != NULL && sav->replay->wsize != 0 && 571 ipsec_chkreplay(ntohl(ah->ah_seq), &seqh, sav) == 0) { 572 SECASVAR_RUNLOCK(sav); 573 AHSTAT_INC(ahs_replay); 574 DPRINTF(("%s: packet replay failure: %s\n", __func__, 575 ipsec_sa2str(sav, buf, sizeof(buf)))); 576 error = EACCES; 577 goto bad; 578 } 579 cryptoid = sav->tdb_cryptoid; 580 SECASVAR_RUNLOCK(sav); 581 582 /* Verify AH header length. */ 583 hl = sizeof(struct ah) + (ah->ah_len * sizeof (u_int32_t)); 584 ahx = sav->tdb_authalgxform; 585 authsize = AUTHSIZE(sav); 586 ahsize = ah_hdrsiz(sav); 587 if (hl != ahsize) { 588 DPRINTF(("%s: bad authenticator length %u (expecting %lu)" 589 " for packet in SA %s/%08lx\n", __func__, hl, 590 (u_long)ahsize, 591 ipsec_address(&sav->sah->saidx.dst, buf, sizeof(buf)), 592 (u_long) ntohl(sav->spi))); 593 AHSTAT_INC(ahs_badauthl); 594 error = EACCES; 595 goto bad; 596 } 597 if (skip + ahsize > m->m_pkthdr.len) { 598 DPRINTF(("%s: bad mbuf length %u (expecting %lu)" 599 " for packet in SA %s/%08lx\n", __func__, 600 m->m_pkthdr.len, (u_long)(skip + ahsize), 601 ipsec_address(&sav->sah->saidx.dst, buf, sizeof(buf)), 602 (u_long) ntohl(sav->spi))); 603 AHSTAT_INC(ahs_badauthl); 604 error = EACCES; 605 goto bad; 606 } 607 AHSTAT_ADD(ahs_ibytes, m->m_pkthdr.len - skip - hl); 608 609 /* Get crypto descriptors. */ 610 crp = crypto_getreq(cryptoid, M_NOWAIT); 611 if (crp == NULL) { 612 DPRINTF(("%s: failed to acquire crypto descriptor\n", 613 __func__)); 614 AHSTAT_INC(ahs_crypto); 615 error = ENOBUFS; 616 goto bad; 617 } 618 619 crp->crp_payload_start = 0; 620 crp->crp_payload_length = m->m_pkthdr.len; 621 crp->crp_digest_start = skip + rplen; 622 623 /* Allocate IPsec-specific opaque crypto info. */ 624 xd = malloc(sizeof(*xd) + skip + rplen + authsize, M_AH, 625 M_NOWAIT | M_ZERO); 626 if (xd == NULL) { 627 DPRINTF(("%s: failed to allocate xform_data\n", __func__)); 628 AHSTAT_INC(ahs_crypto); 629 crypto_freereq(crp); 630 error = ENOBUFS; 631 goto bad; 632 } 633 634 /* 635 * Save the authenticator, the skipped portion of the packet, 636 * and the AH header. 637 */ 638 m_copydata(m, 0, skip + rplen + authsize, (caddr_t)(xd + 1)); 639 640 /* Zeroize the authenticator on the packet. */ 641 m_copyback(m, skip + rplen, authsize, ipseczeroes); 642 643 /* Save ah_nxt, since ah pointer can become invalid after "massage" */ 644 hl = ah->ah_nxt; 645 646 /* "Massage" the packet headers for crypto processing. */ 647 error = ah_massage_headers(&m, sav->sah->saidx.dst.sa.sa_family, 648 skip, ahx->type, 0); 649 if (error != 0) { 650 /* NB: mbuf is free'd by ah_massage_headers */ 651 AHSTAT_INC(ahs_hdrops); 652 free(xd, M_AH); 653 crypto_freereq(crp); 654 key_freesav(&sav); 655 return (error); 656 } 657 658 /* Crypto operation descriptor. */ 659 crp->crp_op = CRYPTO_OP_COMPUTE_DIGEST; 660 crp->crp_flags = CRYPTO_F_CBIFSYNC; 661 crypto_use_mbuf(crp, m); 662 crp->crp_callback = ah_input_cb; 663 crp->crp_opaque = xd; 664 665 if (sav->flags & SADB_X_SAFLAGS_ESN && 666 sav->replay != NULL && sav->replay->wsize != 0) { 667 seqh = htonl(seqh); 668 memcpy(crp->crp_esn, &seqh, sizeof(seqh)); 669 } 670 671 /* These are passed as-is to the callback. */ 672 xd->sav = sav; 673 xd->nxt = hl; 674 xd->protoff = protoff; 675 xd->skip = skip; 676 xd->cryptoid = cryptoid; 677 xd->vnet = curvnet; 678 if (V_async_crypto) 679 return (crypto_dispatch_async(crp, CRYPTO_ASYNC_ORDERED)); 680 else 681 return (crypto_dispatch(crp)); 682 bad: 683 m_freem(m); 684 key_freesav(&sav); 685 return (error); 686 } 687 688 /* 689 * AH input callback from the crypto driver. 690 */ 691 static int 692 ah_input_cb(struct cryptop *crp) 693 { 694 IPSEC_DEBUG_DECLARE(char buf[IPSEC_ADDRSTRLEN]); 695 unsigned char calc[AH_ALEN_MAX]; 696 struct mbuf *m; 697 struct xform_data *xd; 698 struct secasvar *sav; 699 struct secasindex *saidx; 700 caddr_t ptr; 701 crypto_session_t cryptoid; 702 int authsize, rplen, ahsize, error, skip, protoff; 703 uint8_t nxt; 704 705 SECASVAR_RLOCK_TRACKER; 706 707 m = crp->crp_buf.cb_mbuf; 708 xd = crp->crp_opaque; 709 CURVNET_SET(xd->vnet); 710 sav = xd->sav; 711 skip = xd->skip; 712 nxt = xd->nxt; 713 protoff = xd->protoff; 714 cryptoid = xd->cryptoid; 715 saidx = &sav->sah->saidx; 716 IPSEC_ASSERT(saidx->dst.sa.sa_family == AF_INET || 717 saidx->dst.sa.sa_family == AF_INET6, 718 ("unexpected protocol family %u", saidx->dst.sa.sa_family)); 719 720 /* Check for crypto errors. */ 721 if (crp->crp_etype) { 722 if (crp->crp_etype == EAGAIN) { 723 /* Reset the session ID */ 724 if (ipsec_updateid(sav, &crp->crp_session, &cryptoid) != 0) 725 crypto_freesession(cryptoid); 726 xd->cryptoid = crp->crp_session; 727 CURVNET_RESTORE(); 728 return (crypto_dispatch(crp)); 729 } 730 AHSTAT_INC(ahs_noxform); 731 DPRINTF(("%s: crypto error %d\n", __func__, crp->crp_etype)); 732 error = crp->crp_etype; 733 goto bad; 734 } else { 735 AHSTAT_INC(ahs_hist[sav->alg_auth]); 736 crypto_freereq(crp); /* No longer needed. */ 737 crp = NULL; 738 } 739 740 /* Shouldn't happen... */ 741 if (m == NULL) { 742 AHSTAT_INC(ahs_crypto); 743 DPRINTF(("%s: bogus returned buffer from crypto\n", __func__)); 744 error = EINVAL; 745 goto bad; 746 } 747 748 /* Figure out header size. */ 749 rplen = HDRSIZE(sav); 750 authsize = AUTHSIZE(sav); 751 ahsize = ah_hdrsiz(sav); 752 753 /* Copy authenticator off the packet. */ 754 m_copydata(m, skip + rplen, authsize, calc); 755 756 /* Verify authenticator. */ 757 ptr = (caddr_t) (xd + 1); 758 if (timingsafe_bcmp(ptr + skip + rplen, calc, authsize)) { 759 DPRINTF(("%s: authentication hash mismatch for packet " 760 "in SA %s/%08lx\n", __func__, 761 ipsec_address(&saidx->dst, buf, sizeof(buf)), 762 (u_long) ntohl(sav->spi))); 763 AHSTAT_INC(ahs_badauth); 764 error = EACCES; 765 goto bad; 766 } 767 /* Fix the Next Protocol field. */ 768 ((uint8_t *) ptr)[protoff] = nxt; 769 770 /* Copyback the saved (uncooked) network headers. */ 771 m_copyback(m, 0, skip, ptr); 772 free(xd, M_AH), xd = NULL; /* No longer needed */ 773 774 /* 775 * Header is now authenticated. 776 */ 777 m->m_flags |= M_AUTHIPHDR|M_AUTHIPDGM; 778 779 /* 780 * Update replay sequence number, if appropriate. 781 */ 782 if (sav->replay) { 783 u_int32_t seq; 784 785 m_copydata(m, skip + offsetof(struct newah, ah_seq), 786 sizeof (seq), (caddr_t) &seq); 787 SECASVAR_RLOCK(sav); 788 if (ipsec_updatereplay(ntohl(seq), sav)) { 789 SECASVAR_RUNLOCK(sav); 790 AHSTAT_INC(ahs_replay); 791 error = EACCES; 792 goto bad; 793 } 794 SECASVAR_RUNLOCK(sav); 795 } 796 797 /* 798 * Remove the AH header and authenticator from the mbuf. 799 */ 800 error = m_striphdr(m, skip, ahsize); 801 if (error) { 802 DPRINTF(("%s: mangled mbuf chain for SA %s/%08lx\n", __func__, 803 ipsec_address(&saidx->dst, buf, sizeof(buf)), 804 (u_long) ntohl(sav->spi))); 805 AHSTAT_INC(ahs_hdrops); 806 goto bad; 807 } 808 809 switch (saidx->dst.sa.sa_family) { 810 #ifdef INET6 811 case AF_INET6: 812 error = ipsec6_common_input_cb(m, sav, skip, protoff); 813 break; 814 #endif 815 #ifdef INET 816 case AF_INET: 817 error = ipsec4_common_input_cb(m, sav, skip, protoff); 818 break; 819 #endif 820 default: 821 panic("%s: Unexpected address family: %d saidx=%p", __func__, 822 saidx->dst.sa.sa_family, saidx); 823 } 824 CURVNET_RESTORE(); 825 return error; 826 bad: 827 CURVNET_RESTORE(); 828 if (sav) 829 key_freesav(&sav); 830 if (m != NULL) 831 m_freem(m); 832 if (xd != NULL) 833 free(xd, M_AH); 834 if (crp != NULL) 835 crypto_freereq(crp); 836 return error; 837 } 838 839 /* 840 * AH output routine, called by ipsec[46]_perform_request(). 841 */ 842 static int 843 ah_output(struct mbuf *m, struct secpolicy *sp, struct secasvar *sav, 844 u_int idx, int skip, int protoff) 845 { 846 IPSEC_DEBUG_DECLARE(char buf[IPSEC_ADDRSTRLEN]); 847 const struct auth_hash *ahx; 848 struct xform_data *xd; 849 struct mbuf *mi; 850 struct cryptop *crp; 851 struct newah *ah; 852 crypto_session_t cryptoid; 853 uint16_t iplen; 854 int error, rplen, authsize, ahsize, maxpacketsize, roff; 855 uint8_t prot; 856 uint32_t seqh; 857 858 SECASVAR_RLOCK_TRACKER; 859 860 IPSEC_ASSERT(sav != NULL, ("null SA")); 861 ahx = sav->tdb_authalgxform; 862 IPSEC_ASSERT(ahx != NULL, ("null authentication xform")); 863 864 AHSTAT_INC(ahs_output); 865 866 /* Figure out header size. */ 867 rplen = HDRSIZE(sav); 868 authsize = AUTHSIZE(sav); 869 ahsize = ah_hdrsiz(sav); 870 871 /* Check for maximum packet size violations. */ 872 switch (sav->sah->saidx.dst.sa.sa_family) { 873 #ifdef INET 874 case AF_INET: 875 maxpacketsize = IP_MAXPACKET; 876 break; 877 #endif /* INET */ 878 #ifdef INET6 879 case AF_INET6: 880 maxpacketsize = IPV6_MAXPACKET; 881 break; 882 #endif /* INET6 */ 883 default: 884 DPRINTF(("%s: unknown/unsupported protocol family %u, " 885 "SA %s/%08lx\n", __func__, 886 sav->sah->saidx.dst.sa.sa_family, 887 ipsec_address(&sav->sah->saidx.dst, buf, sizeof(buf)), 888 (u_long) ntohl(sav->spi))); 889 AHSTAT_INC(ahs_nopf); 890 error = EPFNOSUPPORT; 891 goto bad; 892 } 893 if (ahsize + m->m_pkthdr.len > maxpacketsize) { 894 DPRINTF(("%s: packet in SA %s/%08lx got too big " 895 "(len %u, max len %u)\n", __func__, 896 ipsec_address(&sav->sah->saidx.dst, buf, sizeof(buf)), 897 (u_long) ntohl(sav->spi), 898 ahsize + m->m_pkthdr.len, maxpacketsize)); 899 AHSTAT_INC(ahs_toobig); 900 error = EMSGSIZE; 901 goto bad; 902 } 903 904 /* Update the counters. */ 905 AHSTAT_ADD(ahs_obytes, m->m_pkthdr.len - skip); 906 907 m = m_unshare(m, M_NOWAIT); 908 if (m == NULL) { 909 DPRINTF(("%s: cannot clone mbuf chain, SA %s/%08lx\n", __func__, 910 ipsec_address(&sav->sah->saidx.dst, buf, sizeof(buf)), 911 (u_long) ntohl(sav->spi))); 912 AHSTAT_INC(ahs_hdrops); 913 error = ENOBUFS; 914 goto bad; 915 } 916 917 /* Inject AH header. */ 918 mi = m_makespace(m, skip, ahsize, &roff); 919 if (mi == NULL) { 920 DPRINTF(("%s: failed to inject %u byte AH header for SA " 921 "%s/%08lx\n", __func__, ahsize, 922 ipsec_address(&sav->sah->saidx.dst, buf, sizeof(buf)), 923 (u_long) ntohl(sav->spi))); 924 AHSTAT_INC(ahs_hdrops); /*XXX differs from openbsd */ 925 error = ENOBUFS; 926 goto bad; 927 } 928 929 /* 930 * The AH header is guaranteed by m_makespace() to be in 931 * contiguous memory, at roff bytes offset into the returned mbuf. 932 */ 933 ah = (struct newah *)(mtod(mi, caddr_t) + roff); 934 935 /* Initialize the AH header. */ 936 m_copydata(m, protoff, sizeof(u_int8_t), (caddr_t) &ah->ah_nxt); 937 ah->ah_len = (ahsize - sizeof(struct ah)) / sizeof(u_int32_t); 938 ah->ah_reserve = 0; 939 ah->ah_spi = sav->spi; 940 941 /* Zeroize authenticator. */ 942 m_copyback(m, skip + rplen, authsize, ipseczeroes); 943 944 /* Zeroize padding */ 945 m_copyback(m, skip + rplen + authsize, ahsize - (rplen + authsize), 946 ipseczeroes); 947 948 /* Insert packet replay counter, as requested. */ 949 SECASVAR_RLOCK(sav); 950 if (sav->replay) { 951 SECREPLAY_LOCK(sav->replay); 952 if ((sav->replay->count == ~0 || 953 (!(sav->flags & SADB_X_SAFLAGS_ESN) && 954 ((uint32_t)sav->replay->count) == ~0)) && 955 (sav->flags & SADB_X_EXT_CYCSEQ) == 0) { 956 SECREPLAY_UNLOCK(sav->replay); 957 SECASVAR_RUNLOCK(sav); 958 DPRINTF(("%s: replay counter wrapped for SA %s/%08lx\n", 959 __func__, ipsec_address(&sav->sah->saidx.dst, buf, 960 sizeof(buf)), (u_long) ntohl(sav->spi))); 961 AHSTAT_INC(ahs_wrap); 962 error = EACCES; 963 goto bad; 964 } 965 #ifdef REGRESSION 966 /* Emulate replay attack when ipsec_replay is TRUE. */ 967 if (!V_ipsec_replay) 968 #endif 969 sav->replay->count++; 970 ah->ah_seq = htonl((uint32_t)sav->replay->count); 971 SECREPLAY_UNLOCK(sav->replay); 972 } 973 cryptoid = sav->tdb_cryptoid; 974 SECASVAR_RUNLOCK(sav); 975 976 /* Get crypto descriptors. */ 977 crp = crypto_getreq(cryptoid, M_NOWAIT); 978 if (crp == NULL) { 979 DPRINTF(("%s: failed to acquire crypto descriptors\n", 980 __func__)); 981 AHSTAT_INC(ahs_crypto); 982 error = ENOBUFS; 983 goto bad; 984 } 985 986 crp->crp_payload_start = 0; 987 crp->crp_payload_length = m->m_pkthdr.len; 988 crp->crp_digest_start = skip + rplen; 989 990 /* Allocate IPsec-specific opaque crypto info. */ 991 xd = malloc(sizeof(struct xform_data) + skip, M_AH, 992 M_NOWAIT | M_ZERO); 993 if (xd == NULL) { 994 crypto_freereq(crp); 995 DPRINTF(("%s: failed to allocate xform_data\n", __func__)); 996 AHSTAT_INC(ahs_crypto); 997 error = ENOBUFS; 998 goto bad; 999 } 1000 1001 /* Save the skipped portion of the packet. */ 1002 m_copydata(m, 0, skip, (caddr_t) (xd + 1)); 1003 1004 /* 1005 * Fix IP header length on the header used for 1006 * authentication. We don't need to fix the original 1007 * header length as it will be fixed by our caller. 1008 */ 1009 switch (sav->sah->saidx.dst.sa.sa_family) { 1010 #ifdef INET 1011 case AF_INET: 1012 bcopy(((caddr_t)(xd + 1)) + 1013 offsetof(struct ip, ip_len), 1014 (caddr_t) &iplen, sizeof(u_int16_t)); 1015 iplen = htons(ntohs(iplen) + ahsize); 1016 m_copyback(m, offsetof(struct ip, ip_len), 1017 sizeof(u_int16_t), (caddr_t) &iplen); 1018 break; 1019 #endif /* INET */ 1020 1021 #ifdef INET6 1022 case AF_INET6: 1023 bcopy(((caddr_t)(xd + 1)) + 1024 offsetof(struct ip6_hdr, ip6_plen), 1025 (caddr_t) &iplen, sizeof(uint16_t)); 1026 iplen = htons(ntohs(iplen) + ahsize); 1027 m_copyback(m, offsetof(struct ip6_hdr, ip6_plen), 1028 sizeof(uint16_t), (caddr_t) &iplen); 1029 break; 1030 #endif /* INET6 */ 1031 } 1032 1033 /* Fix the Next Header field in saved header. */ 1034 ((uint8_t *) (xd + 1))[protoff] = IPPROTO_AH; 1035 1036 /* Update the Next Protocol field in the IP header. */ 1037 prot = IPPROTO_AH; 1038 m_copyback(m, protoff, sizeof(uint8_t), (caddr_t) &prot); 1039 1040 /* "Massage" the packet headers for crypto processing. */ 1041 error = ah_massage_headers(&m, sav->sah->saidx.dst.sa.sa_family, 1042 skip, ahx->type, 1); 1043 if (error != 0) { 1044 m = NULL; /* mbuf was free'd by ah_massage_headers. */ 1045 free(xd, M_AH); 1046 crypto_freereq(crp); 1047 goto bad; 1048 } 1049 1050 /* Crypto operation descriptor. */ 1051 crp->crp_op = CRYPTO_OP_COMPUTE_DIGEST; 1052 crp->crp_flags = CRYPTO_F_CBIFSYNC; 1053 crypto_use_mbuf(crp, m); 1054 crp->crp_callback = ah_output_cb; 1055 crp->crp_opaque = xd; 1056 1057 if (sav->flags & SADB_X_SAFLAGS_ESN && sav->replay != NULL) { 1058 SECREPLAY_LOCK(sav->replay); 1059 seqh = htonl((uint32_t)(sav->replay->count >> IPSEC_SEQH_SHIFT)); 1060 memcpy(crp->crp_esn, &seqh, sizeof(seqh)); 1061 SECREPLAY_UNLOCK(sav->replay); 1062 } 1063 1064 /* These are passed as-is to the callback. */ 1065 xd->sp = sp; 1066 xd->sav = sav; 1067 xd->skip = skip; 1068 xd->idx = idx; 1069 xd->cryptoid = cryptoid; 1070 xd->vnet = curvnet; 1071 1072 if (V_async_crypto) 1073 return (crypto_dispatch_async(crp, CRYPTO_ASYNC_ORDERED)); 1074 else 1075 return (crypto_dispatch(crp)); 1076 bad: 1077 if (m) 1078 m_freem(m); 1079 key_freesav(&sav); 1080 key_freesp(&sp); 1081 return (error); 1082 } 1083 1084 /* 1085 * AH output callback from the crypto driver. 1086 */ 1087 static int 1088 ah_output_cb(struct cryptop *crp) 1089 { 1090 struct xform_data *xd; 1091 struct secpolicy *sp; 1092 struct secasvar *sav; 1093 struct mbuf *m; 1094 crypto_session_t cryptoid; 1095 caddr_t ptr; 1096 u_int idx; 1097 int skip, error; 1098 1099 m = crp->crp_buf.cb_mbuf; 1100 xd = (struct xform_data *) crp->crp_opaque; 1101 CURVNET_SET(xd->vnet); 1102 sp = xd->sp; 1103 sav = xd->sav; 1104 skip = xd->skip; 1105 idx = xd->idx; 1106 cryptoid = xd->cryptoid; 1107 ptr = (caddr_t) (xd + 1); 1108 1109 /* Check for crypto errors. */ 1110 if (crp->crp_etype) { 1111 if (crp->crp_etype == EAGAIN) { 1112 /* Reset the session ID */ 1113 if (ipsec_updateid(sav, &crp->crp_session, &cryptoid) != 0) 1114 crypto_freesession(cryptoid); 1115 xd->cryptoid = crp->crp_session; 1116 CURVNET_RESTORE(); 1117 return (crypto_dispatch(crp)); 1118 } 1119 AHSTAT_INC(ahs_noxform); 1120 DPRINTF(("%s: crypto error %d\n", __func__, crp->crp_etype)); 1121 error = crp->crp_etype; 1122 m_freem(m); 1123 goto bad; 1124 } 1125 1126 /* Shouldn't happen... */ 1127 if (m == NULL) { 1128 AHSTAT_INC(ahs_crypto); 1129 DPRINTF(("%s: bogus returned buffer from crypto\n", __func__)); 1130 error = EINVAL; 1131 goto bad; 1132 } 1133 /* 1134 * Copy original headers (with the new protocol number) back 1135 * in place. 1136 */ 1137 m_copyback(m, 0, skip, ptr); 1138 1139 free(xd, M_AH); 1140 crypto_freereq(crp); 1141 AHSTAT_INC(ahs_hist[sav->alg_auth]); 1142 #ifdef REGRESSION 1143 /* Emulate man-in-the-middle attack when ipsec_integrity is TRUE. */ 1144 if (V_ipsec_integrity) { 1145 int alen; 1146 1147 /* 1148 * Corrupt HMAC if we want to test integrity verification of 1149 * the other side. 1150 */ 1151 alen = AUTHSIZE(sav); 1152 m_copyback(m, m->m_pkthdr.len - alen, alen, ipseczeroes); 1153 } 1154 #endif 1155 1156 /* NB: m is reclaimed by ipsec_process_done. */ 1157 error = ipsec_process_done(m, sp, sav, idx); 1158 CURVNET_RESTORE(); 1159 return (error); 1160 bad: 1161 CURVNET_RESTORE(); 1162 free(xd, M_AH); 1163 crypto_freereq(crp); 1164 key_freesav(&sav); 1165 key_freesp(&sp); 1166 return (error); 1167 } 1168 1169 static struct xformsw ah_xformsw = { 1170 .xf_type = XF_AH, 1171 .xf_name = "IPsec AH", 1172 .xf_init = ah_init, 1173 .xf_cleanup = ah_cleanup, 1174 .xf_input = ah_input, 1175 .xf_output = ah_output, 1176 }; 1177 1178 SYSINIT(ah_xform_init, SI_SUB_PROTO_DOMAIN, SI_ORDER_MIDDLE, 1179 xform_attach, &ah_xformsw); 1180 SYSUNINIT(ah_xform_uninit, SI_SUB_PROTO_DOMAIN, SI_ORDER_MIDDLE, 1181 xform_detach, &ah_xformsw); 1182