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sys/netipsec/xform_ah.c
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1 /* $FreeBSD: releng/10.0/sys/netipsec/xform_ah.c 253088 2013-07-09 10:08:13Z ae $ */ 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/sysctl.h> 49 50 #include <net/if.h> 51 #include <net/vnet.h> 52 53 #include <netinet/in.h> 54 #include <netinet/in_systm.h> 55 #include <netinet/ip.h> 56 #include <netinet/ip_ecn.h> 57 #include <netinet/ip6.h> 58 59 #include <net/route.h> 60 #include <netipsec/ipsec.h> 61 #include <netipsec/ah.h> 62 #include <netipsec/ah_var.h> 63 #include <netipsec/xform.h> 64 65 #ifdef INET6 66 #include <netinet6/ip6_var.h> 67 #include <netipsec/ipsec6.h> 68 #include <netinet6/ip6_ecn.h> 69 #endif 70 71 #include <netipsec/key.h> 72 #include <netipsec/key_debug.h> 73 74 #include <opencrypto/cryptodev.h> 75 76 /* 77 * Return header size in bytes. The old protocol did not support 78 * the replay counter; the new protocol always includes the counter. 79 */ 80 #define HDRSIZE(sav) \ 81 (((sav)->flags & SADB_X_EXT_OLD) ? \ 82 sizeof (struct ah) : sizeof (struct ah) + sizeof (u_int32_t)) 83 /* 84 * Return authenticator size in bytes. The old protocol is known 85 * to use a fixed 16-byte authenticator. The new algorithm use 12-byte 86 * authenticator. 87 */ 88 #define AUTHSIZE(sav) ah_authsize(sav) 89 90 VNET_DEFINE(int, ah_enable) = 1; /* control flow of packets with AH */ 91 VNET_DEFINE(int, ah_cleartos) = 1; /* clear ip_tos when doing AH calc */ 92 VNET_PCPUSTAT_DEFINE(struct ahstat, ahstat); 93 VNET_PCPUSTAT_SYSINIT(ahstat); 94 95 #ifdef VIMAGE 96 VNET_PCPUSTAT_SYSUNINIT(ahstat); 97 #endif /* VIMAGE */ 98 99 #ifdef INET 100 SYSCTL_DECL(_net_inet_ah); 101 SYSCTL_VNET_INT(_net_inet_ah, OID_AUTO, 102 ah_enable, CTLFLAG_RW, &VNET_NAME(ah_enable), 0, ""); 103 SYSCTL_VNET_INT(_net_inet_ah, OID_AUTO, 104 ah_cleartos, CTLFLAG_RW, &VNET_NAME(ah_cleartos), 0, ""); 105 SYSCTL_VNET_PCPUSTAT(_net_inet_ah, IPSECCTL_STATS, stats, struct ahstat, 106 ahstat, "AH statistics (struct ahstat, netipsec/ah_var.h)"); 107 #endif 108 109 static unsigned char ipseczeroes[256]; /* larger than an ip6 extension hdr */ 110 111 static int ah_input_cb(struct cryptop*); 112 static int ah_output_cb(struct cryptop*); 113 114 static int 115 ah_authsize(struct secasvar *sav) 116 { 117 118 IPSEC_ASSERT(sav != NULL, ("%s: sav == NULL", __func__)); 119 120 if (sav->flags & SADB_X_EXT_OLD) 121 return 16; 122 123 switch (sav->alg_auth) { 124 case SADB_X_AALG_SHA2_256: 125 return 16; 126 case SADB_X_AALG_SHA2_384: 127 return 24; 128 case SADB_X_AALG_SHA2_512: 129 return 32; 130 default: 131 return AH_HMAC_HASHLEN; 132 } 133 /* NOTREACHED */ 134 } 135 /* 136 * NB: this is public for use by the PF_KEY support. 137 */ 138 struct auth_hash * 139 ah_algorithm_lookup(int alg) 140 { 141 if (alg > SADB_AALG_MAX) 142 return NULL; 143 switch (alg) { 144 case SADB_X_AALG_NULL: 145 return &auth_hash_null; 146 case SADB_AALG_MD5HMAC: 147 return &auth_hash_hmac_md5; 148 case SADB_AALG_SHA1HMAC: 149 return &auth_hash_hmac_sha1; 150 case SADB_X_AALG_RIPEMD160HMAC: 151 return &auth_hash_hmac_ripemd_160; 152 case SADB_X_AALG_MD5: 153 return &auth_hash_key_md5; 154 case SADB_X_AALG_SHA: 155 return &auth_hash_key_sha1; 156 case SADB_X_AALG_SHA2_256: 157 return &auth_hash_hmac_sha2_256; 158 case SADB_X_AALG_SHA2_384: 159 return &auth_hash_hmac_sha2_384; 160 case SADB_X_AALG_SHA2_512: 161 return &auth_hash_hmac_sha2_512; 162 } 163 return NULL; 164 } 165 166 size_t 167 ah_hdrsiz(struct secasvar *sav) 168 { 169 size_t size; 170 171 if (sav != NULL) { 172 int authsize; 173 IPSEC_ASSERT(sav->tdb_authalgxform != NULL, ("null xform")); 174 /*XXX not right for null algorithm--does it matter??*/ 175 authsize = AUTHSIZE(sav); 176 size = roundup(authsize, sizeof (u_int32_t)) + HDRSIZE(sav); 177 } else { 178 /* default guess */ 179 size = sizeof (struct ah) + sizeof (u_int32_t) + 16; 180 } 181 return size; 182 } 183 184 /* 185 * NB: public for use by esp_init. 186 */ 187 int 188 ah_init0(struct secasvar *sav, struct xformsw *xsp, struct cryptoini *cria) 189 { 190 struct auth_hash *thash; 191 int keylen; 192 193 thash = ah_algorithm_lookup(sav->alg_auth); 194 if (thash == NULL) { 195 DPRINTF(("%s: unsupported authentication algorithm %u\n", 196 __func__, sav->alg_auth)); 197 return EINVAL; 198 } 199 /* 200 * Verify the replay state block allocation is consistent with 201 * the protocol type. We check here so we can make assumptions 202 * later during protocol processing. 203 */ 204 /* NB: replay state is setup elsewhere (sigh) */ 205 if (((sav->flags&SADB_X_EXT_OLD) == 0) ^ (sav->replay != NULL)) { 206 DPRINTF(("%s: replay state block inconsistency, " 207 "%s algorithm %s replay state\n", __func__, 208 (sav->flags & SADB_X_EXT_OLD) ? "old" : "new", 209 sav->replay == NULL ? "without" : "with")); 210 return EINVAL; 211 } 212 if (sav->key_auth == NULL) { 213 DPRINTF(("%s: no authentication key for %s algorithm\n", 214 __func__, thash->name)); 215 return EINVAL; 216 } 217 keylen = _KEYLEN(sav->key_auth); 218 if (keylen != thash->keysize && thash->keysize != 0) { 219 DPRINTF(("%s: invalid keylength %d, algorithm %s requires " 220 "keysize %d\n", __func__, 221 keylen, thash->name, thash->keysize)); 222 return EINVAL; 223 } 224 225 sav->tdb_xform = xsp; 226 sav->tdb_authalgxform = thash; 227 228 /* Initialize crypto session. */ 229 bzero(cria, sizeof (*cria)); 230 cria->cri_alg = sav->tdb_authalgxform->type; 231 cria->cri_klen = _KEYBITS(sav->key_auth); 232 cria->cri_key = sav->key_auth->key_data; 233 cria->cri_mlen = AUTHSIZE(sav); 234 235 return 0; 236 } 237 238 /* 239 * ah_init() is called when an SPI is being set up. 240 */ 241 static int 242 ah_init(struct secasvar *sav, struct xformsw *xsp) 243 { 244 struct cryptoini cria; 245 int error; 246 247 error = ah_init0(sav, xsp, &cria); 248 return error ? error : 249 crypto_newsession(&sav->tdb_cryptoid, &cria, V_crypto_support); 250 } 251 252 /* 253 * Paranoia. 254 * 255 * NB: public for use by esp_zeroize (XXX). 256 */ 257 int 258 ah_zeroize(struct secasvar *sav) 259 { 260 int err; 261 262 if (sav->key_auth) 263 bzero(sav->key_auth->key_data, _KEYLEN(sav->key_auth)); 264 265 err = crypto_freesession(sav->tdb_cryptoid); 266 sav->tdb_cryptoid = 0; 267 sav->tdb_authalgxform = NULL; 268 sav->tdb_xform = NULL; 269 return err; 270 } 271 272 /* 273 * Massage IPv4/IPv6 headers for AH processing. 274 */ 275 static int 276 ah_massage_headers(struct mbuf **m0, int proto, int skip, int alg, int out) 277 { 278 struct mbuf *m = *m0; 279 unsigned char *ptr; 280 int off, count; 281 282 #ifdef INET 283 struct ip *ip; 284 #endif /* INET */ 285 286 #ifdef INET6 287 struct ip6_ext *ip6e; 288 struct ip6_hdr ip6; 289 int alloc, len, ad; 290 #endif /* INET6 */ 291 292 switch (proto) { 293 #ifdef INET 294 case AF_INET: 295 /* 296 * This is the least painful way of dealing with IPv4 header 297 * and option processing -- just make sure they're in 298 * contiguous memory. 299 */ 300 *m0 = m = m_pullup(m, skip); 301 if (m == NULL) { 302 DPRINTF(("%s: m_pullup failed\n", __func__)); 303 return ENOBUFS; 304 } 305 306 /* Fix the IP header */ 307 ip = mtod(m, struct ip *); 308 if (V_ah_cleartos) 309 ip->ip_tos = 0; 310 ip->ip_ttl = 0; 311 ip->ip_sum = 0; 312 313 if (alg == CRYPTO_MD5_KPDK || alg == CRYPTO_SHA1_KPDK) 314 ip->ip_off &= htons(IP_DF); 315 else 316 ip->ip_off = htons(0); 317 318 ptr = mtod(m, unsigned char *) + sizeof(struct ip); 319 320 /* IPv4 option processing */ 321 for (off = sizeof(struct ip); off < skip;) { 322 if (ptr[off] == IPOPT_EOL || ptr[off] == IPOPT_NOP || 323 off + 1 < skip) 324 ; 325 else { 326 DPRINTF(("%s: illegal IPv4 option length for " 327 "option %d\n", __func__, ptr[off])); 328 329 m_freem(m); 330 return EINVAL; 331 } 332 333 switch (ptr[off]) { 334 case IPOPT_EOL: 335 off = skip; /* End the loop. */ 336 break; 337 338 case IPOPT_NOP: 339 off++; 340 break; 341 342 case IPOPT_SECURITY: /* 0x82 */ 343 case 0x85: /* Extended security. */ 344 case 0x86: /* Commercial security. */ 345 case 0x94: /* Router alert */ 346 case 0x95: /* RFC1770 */ 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 off += ptr[off + 1]; 358 break; 359 360 case IPOPT_LSRR: 361 case IPOPT_SSRR: 362 /* Sanity check for option length. */ 363 if (ptr[off + 1] < 2) { 364 DPRINTF(("%s: illegal IPv4 option " 365 "length for option %d\n", 366 __func__, ptr[off])); 367 368 m_freem(m); 369 return EINVAL; 370 } 371 372 /* 373 * On output, if we have either of the 374 * source routing options, we should 375 * swap the destination address of the 376 * IP header with the last address 377 * specified in the option, as that is 378 * what the destination's IP header 379 * will look like. 380 */ 381 if (out) 382 bcopy(ptr + off + ptr[off + 1] - 383 sizeof(struct in_addr), 384 &(ip->ip_dst), sizeof(struct in_addr)); 385 386 /* Fall through */ 387 default: 388 /* Sanity check for option length. */ 389 if (ptr[off + 1] < 2) { 390 DPRINTF(("%s: illegal IPv4 option " 391 "length for option %d\n", 392 __func__, ptr[off])); 393 m_freem(m); 394 return EINVAL; 395 } 396 397 /* Zeroize all other options. */ 398 count = ptr[off + 1]; 399 bcopy(ipseczeroes, ptr, count); 400 off += count; 401 break; 402 } 403 404 /* Sanity check. */ 405 if (off > skip) { 406 DPRINTF(("%s: malformed IPv4 options header\n", 407 __func__)); 408 409 m_freem(m); 410 return EINVAL; 411 } 412 } 413 414 break; 415 #endif /* INET */ 416 417 #ifdef INET6 418 case AF_INET6: /* Ugly... */ 419 /* Copy and "cook" the IPv6 header. */ 420 m_copydata(m, 0, sizeof(ip6), (caddr_t) &ip6); 421 422 /* We don't do IPv6 Jumbograms. */ 423 if (ip6.ip6_plen == 0) { 424 DPRINTF(("%s: unsupported IPv6 jumbogram\n", __func__)); 425 m_freem(m); 426 return EMSGSIZE; 427 } 428 429 ip6.ip6_flow = 0; 430 ip6.ip6_hlim = 0; 431 ip6.ip6_vfc &= ~IPV6_VERSION_MASK; 432 ip6.ip6_vfc |= IPV6_VERSION; 433 434 /* Scoped address handling. */ 435 if (IN6_IS_SCOPE_LINKLOCAL(&ip6.ip6_src)) 436 ip6.ip6_src.s6_addr16[1] = 0; 437 if (IN6_IS_SCOPE_LINKLOCAL(&ip6.ip6_dst)) 438 ip6.ip6_dst.s6_addr16[1] = 0; 439 440 /* Done with IPv6 header. */ 441 m_copyback(m, 0, sizeof(struct ip6_hdr), (caddr_t) &ip6); 442 443 /* Let's deal with the remaining headers (if any). */ 444 if (skip - sizeof(struct ip6_hdr) > 0) { 445 if (m->m_len <= skip) { 446 ptr = (unsigned char *) malloc( 447 skip - sizeof(struct ip6_hdr), 448 M_XDATA, M_NOWAIT); 449 if (ptr == NULL) { 450 DPRINTF(("%s: failed to allocate memory" 451 "for IPv6 headers\n",__func__)); 452 m_freem(m); 453 return ENOBUFS; 454 } 455 456 /* 457 * Copy all the protocol headers after 458 * the IPv6 header. 459 */ 460 m_copydata(m, sizeof(struct ip6_hdr), 461 skip - sizeof(struct ip6_hdr), ptr); 462 alloc = 1; 463 } else { 464 /* No need to allocate memory. */ 465 ptr = mtod(m, unsigned char *) + 466 sizeof(struct ip6_hdr); 467 alloc = 0; 468 } 469 } else 470 break; 471 472 off = ip6.ip6_nxt & 0xff; /* Next header type. */ 473 474 for (len = 0; len < skip - sizeof(struct ip6_hdr);) 475 switch (off) { 476 case IPPROTO_HOPOPTS: 477 case IPPROTO_DSTOPTS: 478 ip6e = (struct ip6_ext *) (ptr + len); 479 480 /* 481 * Process the mutable/immutable 482 * options -- borrows heavily from the 483 * KAME code. 484 */ 485 for (count = len + sizeof(struct ip6_ext); 486 count < len + ((ip6e->ip6e_len + 1) << 3);) { 487 if (ptr[count] == IP6OPT_PAD1) { 488 count++; 489 continue; /* Skip padding. */ 490 } 491 492 /* Sanity check. */ 493 if (count > len + 494 ((ip6e->ip6e_len + 1) << 3)) { 495 m_freem(m); 496 497 /* Free, if we allocated. */ 498 if (alloc) 499 free(ptr, M_XDATA); 500 return EINVAL; 501 } 502 503 ad = ptr[count + 1]; 504 505 /* If mutable option, zeroize. */ 506 if (ptr[count] & IP6OPT_MUTABLE) 507 bcopy(ipseczeroes, ptr + count, 508 ptr[count + 1]); 509 510 count += ad; 511 512 /* Sanity check. */ 513 if (count > 514 skip - sizeof(struct ip6_hdr)) { 515 m_freem(m); 516 517 /* Free, if we allocated. */ 518 if (alloc) 519 free(ptr, M_XDATA); 520 return EINVAL; 521 } 522 } 523 524 /* Advance. */ 525 len += ((ip6e->ip6e_len + 1) << 3); 526 off = ip6e->ip6e_nxt; 527 break; 528 529 case IPPROTO_ROUTING: 530 /* 531 * Always include routing headers in 532 * computation. 533 */ 534 ip6e = (struct ip6_ext *) (ptr + len); 535 len += ((ip6e->ip6e_len + 1) << 3); 536 off = ip6e->ip6e_nxt; 537 break; 538 539 default: 540 DPRINTF(("%s: unexpected IPv6 header type %d", 541 __func__, off)); 542 if (alloc) 543 free(ptr, M_XDATA); 544 m_freem(m); 545 return EINVAL; 546 } 547 548 /* Copyback and free, if we allocated. */ 549 if (alloc) { 550 m_copyback(m, sizeof(struct ip6_hdr), 551 skip - sizeof(struct ip6_hdr), ptr); 552 free(ptr, M_XDATA); 553 } 554 555 break; 556 #endif /* INET6 */ 557 } 558 559 return 0; 560 } 561 562 /* 563 * ah_input() gets called to verify that an input packet 564 * passes authentication. 565 */ 566 static int 567 ah_input(struct mbuf *m, struct secasvar *sav, int skip, int protoff) 568 { 569 struct auth_hash *ahx; 570 struct tdb_ident *tdbi; 571 struct tdb_crypto *tc; 572 struct m_tag *mtag; 573 struct newah *ah; 574 int hl, rplen, authsize; 575 576 struct cryptodesc *crda; 577 struct cryptop *crp; 578 579 IPSEC_ASSERT(sav != NULL, ("null SA")); 580 IPSEC_ASSERT(sav->key_auth != NULL, ("null authentication key")); 581 IPSEC_ASSERT(sav->tdb_authalgxform != NULL, 582 ("null authentication xform")); 583 584 /* Figure out header size. */ 585 rplen = HDRSIZE(sav); 586 587 /* XXX don't pullup, just copy header */ 588 IP6_EXTHDR_GET(ah, struct newah *, m, skip, rplen); 589 if (ah == NULL) { 590 DPRINTF(("ah_input: cannot pullup header\n")); 591 AHSTAT_INC(ahs_hdrops); /*XXX*/ 592 m_freem(m); 593 return ENOBUFS; 594 } 595 596 /* Check replay window, if applicable. */ 597 if (sav->replay && !ipsec_chkreplay(ntohl(ah->ah_seq), sav)) { 598 AHSTAT_INC(ahs_replay); 599 DPRINTF(("%s: packet replay failure: %s\n", __func__, 600 ipsec_logsastr(sav))); 601 m_freem(m); 602 return ENOBUFS; 603 } 604 605 /* Verify AH header length. */ 606 hl = ah->ah_len * sizeof (u_int32_t); 607 ahx = sav->tdb_authalgxform; 608 authsize = AUTHSIZE(sav); 609 if (hl != authsize + rplen - sizeof (struct ah)) { 610 DPRINTF(("%s: bad authenticator length %u (expecting %lu)" 611 " for packet in SA %s/%08lx\n", __func__, 612 hl, (u_long) (authsize + rplen - sizeof (struct ah)), 613 ipsec_address(&sav->sah->saidx.dst), 614 (u_long) ntohl(sav->spi))); 615 AHSTAT_INC(ahs_badauthl); 616 m_freem(m); 617 return EACCES; 618 } 619 AHSTAT_ADD(ahs_ibytes, m->m_pkthdr.len - skip - hl); 620 621 /* Get crypto descriptors. */ 622 crp = crypto_getreq(1); 623 if (crp == NULL) { 624 DPRINTF(("%s: failed to acquire crypto descriptor\n",__func__)); 625 AHSTAT_INC(ahs_crypto); 626 m_freem(m); 627 return ENOBUFS; 628 } 629 630 crda = crp->crp_desc; 631 IPSEC_ASSERT(crda != NULL, ("null crypto descriptor")); 632 633 crda->crd_skip = 0; 634 crda->crd_len = m->m_pkthdr.len; 635 crda->crd_inject = skip + rplen; 636 637 /* Authentication operation. */ 638 crda->crd_alg = ahx->type; 639 crda->crd_klen = _KEYBITS(sav->key_auth); 640 crda->crd_key = sav->key_auth->key_data; 641 642 /* Find out if we've already done crypto. */ 643 for (mtag = m_tag_find(m, PACKET_TAG_IPSEC_IN_CRYPTO_DONE, NULL); 644 mtag != NULL; 645 mtag = m_tag_find(m, PACKET_TAG_IPSEC_IN_CRYPTO_DONE, mtag)) { 646 tdbi = (struct tdb_ident *) (mtag + 1); 647 if (tdbi->proto == sav->sah->saidx.proto && 648 tdbi->spi == sav->spi && 649 !bcmp(&tdbi->dst, &sav->sah->saidx.dst, 650 sizeof (union sockaddr_union))) 651 break; 652 } 653 654 /* Allocate IPsec-specific opaque crypto info. */ 655 if (mtag == NULL) { 656 tc = (struct tdb_crypto *) malloc(sizeof (struct tdb_crypto) + 657 skip + rplen + authsize, M_XDATA, M_NOWAIT|M_ZERO); 658 } else { 659 /* Hash verification has already been done successfully. */ 660 tc = (struct tdb_crypto *) malloc(sizeof (struct tdb_crypto), 661 M_XDATA, M_NOWAIT|M_ZERO); 662 } 663 if (tc == NULL) { 664 DPRINTF(("%s: failed to allocate tdb_crypto\n", __func__)); 665 AHSTAT_INC(ahs_crypto); 666 crypto_freereq(crp); 667 m_freem(m); 668 return ENOBUFS; 669 } 670 671 /* Only save information if crypto processing is needed. */ 672 if (mtag == NULL) { 673 int error; 674 675 /* 676 * Save the authenticator, the skipped portion of the packet, 677 * and the AH header. 678 */ 679 m_copydata(m, 0, skip + rplen + authsize, (caddr_t)(tc+1)); 680 681 /* Zeroize the authenticator on the packet. */ 682 m_copyback(m, skip + rplen, authsize, ipseczeroes); 683 684 /* "Massage" the packet headers for crypto processing. */ 685 error = ah_massage_headers(&m, sav->sah->saidx.dst.sa.sa_family, 686 skip, ahx->type, 0); 687 if (error != 0) { 688 /* NB: mbuf is free'd by ah_massage_headers */ 689 AHSTAT_INC(ahs_hdrops); 690 free(tc, M_XDATA); 691 crypto_freereq(crp); 692 return error; 693 } 694 } 695 696 /* Crypto operation descriptor. */ 697 crp->crp_ilen = m->m_pkthdr.len; /* Total input length. */ 698 crp->crp_flags = CRYPTO_F_IMBUF | CRYPTO_F_CBIFSYNC; 699 crp->crp_buf = (caddr_t) m; 700 crp->crp_callback = ah_input_cb; 701 crp->crp_sid = sav->tdb_cryptoid; 702 crp->crp_opaque = (caddr_t) tc; 703 704 /* These are passed as-is to the callback. */ 705 tc->tc_spi = sav->spi; 706 tc->tc_dst = sav->sah->saidx.dst; 707 tc->tc_proto = sav->sah->saidx.proto; 708 tc->tc_nxt = ah->ah_nxt; 709 tc->tc_protoff = protoff; 710 tc->tc_skip = skip; 711 tc->tc_ptr = (caddr_t) mtag; /* Save the mtag we've identified. */ 712 KEY_ADDREFSA(sav); 713 tc->tc_sav = sav; 714 715 if (mtag == NULL) 716 return crypto_dispatch(crp); 717 else 718 return ah_input_cb(crp); 719 } 720 721 /* 722 * AH input callback from the crypto driver. 723 */ 724 static int 725 ah_input_cb(struct cryptop *crp) 726 { 727 int rplen, error, skip, protoff; 728 unsigned char calc[AH_ALEN_MAX]; 729 struct mbuf *m; 730 struct cryptodesc *crd; 731 struct auth_hash *ahx; 732 struct tdb_crypto *tc; 733 struct m_tag *mtag; 734 struct secasvar *sav; 735 struct secasindex *saidx; 736 u_int8_t nxt; 737 caddr_t ptr; 738 int authsize; 739 740 crd = crp->crp_desc; 741 742 tc = (struct tdb_crypto *) crp->crp_opaque; 743 IPSEC_ASSERT(tc != NULL, ("null opaque crypto data area!")); 744 skip = tc->tc_skip; 745 nxt = tc->tc_nxt; 746 protoff = tc->tc_protoff; 747 mtag = (struct m_tag *) tc->tc_ptr; 748 m = (struct mbuf *) crp->crp_buf; 749 750 sav = tc->tc_sav; 751 IPSEC_ASSERT(sav != NULL, ("null SA!")); 752 753 saidx = &sav->sah->saidx; 754 IPSEC_ASSERT(saidx->dst.sa.sa_family == AF_INET || 755 saidx->dst.sa.sa_family == AF_INET6, 756 ("unexpected protocol family %u", saidx->dst.sa.sa_family)); 757 758 ahx = (struct auth_hash *) sav->tdb_authalgxform; 759 760 /* Check for crypto errors. */ 761 if (crp->crp_etype) { 762 if (sav->tdb_cryptoid != 0) 763 sav->tdb_cryptoid = crp->crp_sid; 764 765 if (crp->crp_etype == EAGAIN) 766 return (crypto_dispatch(crp)); 767 768 AHSTAT_INC(ahs_noxform); 769 DPRINTF(("%s: crypto error %d\n", __func__, crp->crp_etype)); 770 error = crp->crp_etype; 771 goto bad; 772 } else { 773 AHSTAT_INC(ahs_hist[sav->alg_auth]); 774 crypto_freereq(crp); /* No longer needed. */ 775 crp = NULL; 776 } 777 778 /* Shouldn't happen... */ 779 if (m == NULL) { 780 AHSTAT_INC(ahs_crypto); 781 DPRINTF(("%s: bogus returned buffer from crypto\n", __func__)); 782 error = EINVAL; 783 goto bad; 784 } 785 786 /* Figure out header size. */ 787 rplen = HDRSIZE(sav); 788 authsize = AUTHSIZE(sav); 789 790 /* Copy authenticator off the packet. */ 791 m_copydata(m, skip + rplen, authsize, calc); 792 793 /* 794 * If we have an mtag, we don't need to verify the authenticator -- 795 * it has been verified by an IPsec-aware NIC. 796 */ 797 if (mtag == NULL) { 798 ptr = (caddr_t) (tc + 1); 799 800 /* Verify authenticator. */ 801 if (bcmp(ptr + skip + rplen, calc, authsize)) { 802 DPRINTF(("%s: authentication hash mismatch for packet " 803 "in SA %s/%08lx\n", __func__, 804 ipsec_address(&saidx->dst), 805 (u_long) ntohl(sav->spi))); 806 AHSTAT_INC(ahs_badauth); 807 error = EACCES; 808 goto bad; 809 } 810 811 /* Fix the Next Protocol field. */ 812 ((u_int8_t *) ptr)[protoff] = nxt; 813 814 /* Copyback the saved (uncooked) network headers. */ 815 m_copyback(m, 0, skip, ptr); 816 } else { 817 /* Fix the Next Protocol field. */ 818 m_copyback(m, protoff, sizeof(u_int8_t), &nxt); 819 } 820 821 free(tc, M_XDATA), tc = NULL; /* No longer needed */ 822 823 /* 824 * Header is now authenticated. 825 */ 826 m->m_flags |= M_AUTHIPHDR|M_AUTHIPDGM; 827 828 /* 829 * Update replay sequence number, if appropriate. 830 */ 831 if (sav->replay) { 832 u_int32_t seq; 833 834 m_copydata(m, skip + offsetof(struct newah, ah_seq), 835 sizeof (seq), (caddr_t) &seq); 836 if (ipsec_updatereplay(ntohl(seq), sav)) { 837 AHSTAT_INC(ahs_replay); 838 error = ENOBUFS; /*XXX as above*/ 839 goto bad; 840 } 841 } 842 843 /* 844 * Remove the AH header and authenticator from the mbuf. 845 */ 846 error = m_striphdr(m, skip, rplen + authsize); 847 if (error) { 848 DPRINTF(("%s: mangled mbuf chain for SA %s/%08lx\n", __func__, 849 ipsec_address(&saidx->dst), (u_long) ntohl(sav->spi))); 850 851 AHSTAT_INC(ahs_hdrops); 852 goto bad; 853 } 854 855 switch (saidx->dst.sa.sa_family) { 856 #ifdef INET6 857 case AF_INET6: 858 error = ipsec6_common_input_cb(m, sav, skip, protoff, mtag); 859 break; 860 #endif 861 #ifdef INET 862 case AF_INET: 863 error = ipsec4_common_input_cb(m, sav, skip, protoff, mtag); 864 break; 865 #endif 866 default: 867 panic("%s: Unexpected address family: %d saidx=%p", __func__, 868 saidx->dst.sa.sa_family, saidx); 869 } 870 871 KEY_FREESAV(&sav); 872 return error; 873 bad: 874 if (sav) 875 KEY_FREESAV(&sav); 876 if (m != NULL) 877 m_freem(m); 878 if (tc != NULL) 879 free(tc, M_XDATA); 880 if (crp != NULL) 881 crypto_freereq(crp); 882 return error; 883 } 884 885 /* 886 * AH output routine, called by ipsec[46]_process_packet(). 887 */ 888 static int 889 ah_output( 890 struct mbuf *m, 891 struct ipsecrequest *isr, 892 struct mbuf **mp, 893 int skip, 894 int protoff) 895 { 896 struct secasvar *sav; 897 struct auth_hash *ahx; 898 struct cryptodesc *crda; 899 struct tdb_crypto *tc; 900 struct mbuf *mi; 901 struct cryptop *crp; 902 u_int16_t iplen; 903 int error, rplen, authsize, maxpacketsize, roff; 904 u_int8_t prot; 905 struct newah *ah; 906 907 sav = isr->sav; 908 IPSEC_ASSERT(sav != NULL, ("null SA")); 909 ahx = sav->tdb_authalgxform; 910 IPSEC_ASSERT(ahx != NULL, ("null authentication xform")); 911 912 AHSTAT_INC(ahs_output); 913 914 /* Figure out header size. */ 915 rplen = HDRSIZE(sav); 916 917 /* Check for maximum packet size violations. */ 918 switch (sav->sah->saidx.dst.sa.sa_family) { 919 #ifdef INET 920 case AF_INET: 921 maxpacketsize = IP_MAXPACKET; 922 break; 923 #endif /* INET */ 924 #ifdef INET6 925 case AF_INET6: 926 maxpacketsize = IPV6_MAXPACKET; 927 break; 928 #endif /* INET6 */ 929 default: 930 DPRINTF(("%s: unknown/unsupported protocol family %u, " 931 "SA %s/%08lx\n", __func__, 932 sav->sah->saidx.dst.sa.sa_family, 933 ipsec_address(&sav->sah->saidx.dst), 934 (u_long) ntohl(sav->spi))); 935 AHSTAT_INC(ahs_nopf); 936 error = EPFNOSUPPORT; 937 goto bad; 938 } 939 authsize = AUTHSIZE(sav); 940 if (rplen + authsize + m->m_pkthdr.len > maxpacketsize) { 941 DPRINTF(("%s: packet in SA %s/%08lx got too big " 942 "(len %u, max len %u)\n", __func__, 943 ipsec_address(&sav->sah->saidx.dst), 944 (u_long) ntohl(sav->spi), 945 rplen + authsize + m->m_pkthdr.len, maxpacketsize)); 946 AHSTAT_INC(ahs_toobig); 947 error = EMSGSIZE; 948 goto bad; 949 } 950 951 /* Update the counters. */ 952 AHSTAT_ADD(ahs_obytes, m->m_pkthdr.len - skip); 953 954 m = m_unshare(m, M_NOWAIT); 955 if (m == NULL) { 956 DPRINTF(("%s: cannot clone mbuf chain, SA %s/%08lx\n", __func__, 957 ipsec_address(&sav->sah->saidx.dst), 958 (u_long) ntohl(sav->spi))); 959 AHSTAT_INC(ahs_hdrops); 960 error = ENOBUFS; 961 goto bad; 962 } 963 964 /* Inject AH header. */ 965 mi = m_makespace(m, skip, rplen + authsize, &roff); 966 if (mi == NULL) { 967 DPRINTF(("%s: failed to inject %u byte AH header for SA " 968 "%s/%08lx\n", __func__, 969 rplen + authsize, 970 ipsec_address(&sav->sah->saidx.dst), 971 (u_long) ntohl(sav->spi))); 972 AHSTAT_INC(ahs_hdrops); /*XXX differs from openbsd */ 973 error = ENOBUFS; 974 goto bad; 975 } 976 977 /* 978 * The AH header is guaranteed by m_makespace() to be in 979 * contiguous memory, at roff bytes offset into the returned mbuf. 980 */ 981 ah = (struct newah *)(mtod(mi, caddr_t) + roff); 982 983 /* Initialize the AH header. */ 984 m_copydata(m, protoff, sizeof(u_int8_t), (caddr_t) &ah->ah_nxt); 985 ah->ah_len = (rplen + authsize - sizeof(struct ah)) / sizeof(u_int32_t); 986 ah->ah_reserve = 0; 987 ah->ah_spi = sav->spi; 988 989 /* Zeroize authenticator. */ 990 m_copyback(m, skip + rplen, authsize, ipseczeroes); 991 992 /* Insert packet replay counter, as requested. */ 993 if (sav->replay) { 994 if (sav->replay->count == ~0 && 995 (sav->flags & SADB_X_EXT_CYCSEQ) == 0) { 996 DPRINTF(("%s: replay counter wrapped for SA %s/%08lx\n", 997 __func__, 998 ipsec_address(&sav->sah->saidx.dst), 999 (u_long) ntohl(sav->spi))); 1000 AHSTAT_INC(ahs_wrap); 1001 error = EINVAL; 1002 goto bad; 1003 } 1004 #ifdef REGRESSION 1005 /* Emulate replay attack when ipsec_replay is TRUE. */ 1006 if (!V_ipsec_replay) 1007 #endif 1008 sav->replay->count++; 1009 ah->ah_seq = htonl(sav->replay->count); 1010 } 1011 1012 /* Get crypto descriptors. */ 1013 crp = crypto_getreq(1); 1014 if (crp == NULL) { 1015 DPRINTF(("%s: failed to acquire crypto descriptors\n", 1016 __func__)); 1017 AHSTAT_INC(ahs_crypto); 1018 error = ENOBUFS; 1019 goto bad; 1020 } 1021 1022 crda = crp->crp_desc; 1023 1024 crda->crd_skip = 0; 1025 crda->crd_inject = skip + rplen; 1026 crda->crd_len = m->m_pkthdr.len; 1027 1028 /* Authentication operation. */ 1029 crda->crd_alg = ahx->type; 1030 crda->crd_key = sav->key_auth->key_data; 1031 crda->crd_klen = _KEYBITS(sav->key_auth); 1032 1033 /* Allocate IPsec-specific opaque crypto info. */ 1034 tc = (struct tdb_crypto *) malloc( 1035 sizeof(struct tdb_crypto) + skip, M_XDATA, M_NOWAIT|M_ZERO); 1036 if (tc == NULL) { 1037 crypto_freereq(crp); 1038 DPRINTF(("%s: failed to allocate tdb_crypto\n", __func__)); 1039 AHSTAT_INC(ahs_crypto); 1040 error = ENOBUFS; 1041 goto bad; 1042 } 1043 1044 /* Save the skipped portion of the packet. */ 1045 m_copydata(m, 0, skip, (caddr_t) (tc + 1)); 1046 1047 /* 1048 * Fix IP header length on the header used for 1049 * authentication. We don't need to fix the original 1050 * header length as it will be fixed by our caller. 1051 */ 1052 switch (sav->sah->saidx.dst.sa.sa_family) { 1053 #ifdef INET 1054 case AF_INET: 1055 bcopy(((caddr_t)(tc + 1)) + 1056 offsetof(struct ip, ip_len), 1057 (caddr_t) &iplen, sizeof(u_int16_t)); 1058 iplen = htons(ntohs(iplen) + rplen + authsize); 1059 m_copyback(m, offsetof(struct ip, ip_len), 1060 sizeof(u_int16_t), (caddr_t) &iplen); 1061 break; 1062 #endif /* INET */ 1063 1064 #ifdef INET6 1065 case AF_INET6: 1066 bcopy(((caddr_t)(tc + 1)) + 1067 offsetof(struct ip6_hdr, ip6_plen), 1068 (caddr_t) &iplen, sizeof(u_int16_t)); 1069 iplen = htons(ntohs(iplen) + rplen + authsize); 1070 m_copyback(m, offsetof(struct ip6_hdr, ip6_plen), 1071 sizeof(u_int16_t), (caddr_t) &iplen); 1072 break; 1073 #endif /* INET6 */ 1074 } 1075 1076 /* Fix the Next Header field in saved header. */ 1077 ((u_int8_t *) (tc + 1))[protoff] = IPPROTO_AH; 1078 1079 /* Update the Next Protocol field in the IP header. */ 1080 prot = IPPROTO_AH; 1081 m_copyback(m, protoff, sizeof(u_int8_t), (caddr_t) &prot); 1082 1083 /* "Massage" the packet headers for crypto processing. */ 1084 error = ah_massage_headers(&m, sav->sah->saidx.dst.sa.sa_family, 1085 skip, ahx->type, 1); 1086 if (error != 0) { 1087 m = NULL; /* mbuf was free'd by ah_massage_headers. */ 1088 free(tc, M_XDATA); 1089 crypto_freereq(crp); 1090 goto bad; 1091 } 1092 1093 /* Crypto operation descriptor. */ 1094 crp->crp_ilen = m->m_pkthdr.len; /* Total input length. */ 1095 crp->crp_flags = CRYPTO_F_IMBUF | CRYPTO_F_CBIFSYNC; 1096 crp->crp_buf = (caddr_t) m; 1097 crp->crp_callback = ah_output_cb; 1098 crp->crp_sid = sav->tdb_cryptoid; 1099 crp->crp_opaque = (caddr_t) tc; 1100 1101 /* These are passed as-is to the callback. */ 1102 tc->tc_isr = isr; 1103 KEY_ADDREFSA(sav); 1104 tc->tc_sav = sav; 1105 tc->tc_spi = sav->spi; 1106 tc->tc_dst = sav->sah->saidx.dst; 1107 tc->tc_proto = sav->sah->saidx.proto; 1108 tc->tc_skip = skip; 1109 tc->tc_protoff = protoff; 1110 1111 return crypto_dispatch(crp); 1112 bad: 1113 if (m) 1114 m_freem(m); 1115 return (error); 1116 } 1117 1118 /* 1119 * AH output callback from the crypto driver. 1120 */ 1121 static int 1122 ah_output_cb(struct cryptop *crp) 1123 { 1124 int skip, protoff, error; 1125 struct tdb_crypto *tc; 1126 struct ipsecrequest *isr; 1127 struct secasvar *sav; 1128 struct mbuf *m; 1129 caddr_t ptr; 1130 1131 tc = (struct tdb_crypto *) crp->crp_opaque; 1132 IPSEC_ASSERT(tc != NULL, ("null opaque data area!")); 1133 skip = tc->tc_skip; 1134 protoff = tc->tc_protoff; 1135 ptr = (caddr_t) (tc + 1); 1136 m = (struct mbuf *) crp->crp_buf; 1137 1138 isr = tc->tc_isr; 1139 IPSECREQUEST_LOCK(isr); 1140 sav = tc->tc_sav; 1141 /* With the isr lock released SA pointer can be updated. */ 1142 if (sav != isr->sav) { 1143 AHSTAT_INC(ahs_notdb); 1144 DPRINTF(("%s: SA expired while in crypto\n", __func__)); 1145 error = ENOBUFS; /*XXX*/ 1146 goto bad; 1147 } 1148 1149 /* Check for crypto errors. */ 1150 if (crp->crp_etype) { 1151 if (sav->tdb_cryptoid != 0) 1152 sav->tdb_cryptoid = crp->crp_sid; 1153 1154 if (crp->crp_etype == EAGAIN) { 1155 IPSECREQUEST_UNLOCK(isr); 1156 return (crypto_dispatch(crp)); 1157 } 1158 1159 AHSTAT_INC(ahs_noxform); 1160 DPRINTF(("%s: crypto error %d\n", __func__, crp->crp_etype)); 1161 error = crp->crp_etype; 1162 goto bad; 1163 } 1164 1165 /* Shouldn't happen... */ 1166 if (m == NULL) { 1167 AHSTAT_INC(ahs_crypto); 1168 DPRINTF(("%s: bogus returned buffer from crypto\n", __func__)); 1169 error = EINVAL; 1170 goto bad; 1171 } 1172 AHSTAT_INC(ahs_hist[sav->alg_auth]); 1173 1174 /* 1175 * Copy original headers (with the new protocol number) back 1176 * in place. 1177 */ 1178 m_copyback(m, 0, skip, ptr); 1179 1180 /* No longer needed. */ 1181 free(tc, M_XDATA); 1182 crypto_freereq(crp); 1183 1184 #ifdef REGRESSION 1185 /* Emulate man-in-the-middle attack when ipsec_integrity is TRUE. */ 1186 if (V_ipsec_integrity) { 1187 int alen; 1188 1189 /* 1190 * Corrupt HMAC if we want to test integrity verification of 1191 * the other side. 1192 */ 1193 alen = AUTHSIZE(sav); 1194 m_copyback(m, m->m_pkthdr.len - alen, alen, ipseczeroes); 1195 } 1196 #endif 1197 1198 /* NB: m is reclaimed by ipsec_process_done. */ 1199 error = ipsec_process_done(m, isr); 1200 KEY_FREESAV(&sav); 1201 IPSECREQUEST_UNLOCK(isr); 1202 return error; 1203 bad: 1204 if (sav) 1205 KEY_FREESAV(&sav); 1206 IPSECREQUEST_UNLOCK(isr); 1207 if (m) 1208 m_freem(m); 1209 free(tc, M_XDATA); 1210 crypto_freereq(crp); 1211 return error; 1212 } 1213 1214 static struct xformsw ah_xformsw = { 1215 XF_AH, XFT_AUTH, "IPsec AH", 1216 ah_init, ah_zeroize, ah_input, ah_output, 1217 }; 1218 1219 static void 1220 ah_attach(void) 1221 { 1222 1223 xform_register(&ah_xformsw); 1224 } 1225 1226 SYSINIT(ah_xform_init, SI_SUB_PROTO_DOMAIN, SI_ORDER_MIDDLE, ah_attach, NULL);
Cache object: d4def4c2274698d9f5bf6a04d5f8f5bd
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