xform_ah.c revision 330566
1/* $FreeBSD: releng/10.3/sys/netipsec/xform_ah.c 330566 2018-03-07 05:53:35Z gordon $ */ 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 <netipsec/ipsec.h> 60#include <netipsec/ah.h> 61#include <netipsec/ah_var.h> 62#include <netipsec/xform.h> 63 64#ifdef INET6 65#include <netinet6/ip6_var.h> 66#include <netipsec/ipsec6.h> 67#include <netinet6/ip6_ecn.h> 68#endif 69 70#include <netipsec/key.h> 71#include <netipsec/key_debug.h> 72 73#include <opencrypto/cryptodev.h> 74 75/* 76 * Return header size in bytes. The old protocol did not support 77 * the replay counter; the new protocol always includes the counter. 78 */ 79#define HDRSIZE(sav) \ 80 (((sav)->flags & SADB_X_EXT_OLD) ? \ 81 sizeof (struct ah) : sizeof (struct ah) + sizeof (u_int32_t)) 82/* 83 * Return authenticator size in bytes. The old protocol is known 84 * to use a fixed 16-byte authenticator. The new algorithm use 12-byte 85 * authenticator. 86 */ 87#define AUTHSIZE(sav) ah_authsize(sav) 88 89VNET_DEFINE(int, ah_enable) = 1; /* control flow of packets with AH */ 90VNET_DEFINE(int, ah_cleartos) = 1; /* clear ip_tos when doing AH calc */ 91VNET_PCPUSTAT_DEFINE(struct ahstat, ahstat); 92VNET_PCPUSTAT_SYSINIT(ahstat); 93 94#ifdef VIMAGE 95VNET_PCPUSTAT_SYSUNINIT(ahstat); 96#endif /* VIMAGE */ 97 98#ifdef INET 99SYSCTL_DECL(_net_inet_ah); 100SYSCTL_VNET_INT(_net_inet_ah, OID_AUTO, 101 ah_enable, CTLFLAG_RW, &VNET_NAME(ah_enable), 0, ""); 102SYSCTL_VNET_INT(_net_inet_ah, OID_AUTO, 103 ah_cleartos, CTLFLAG_RW, &VNET_NAME(ah_cleartos), 0, ""); 104SYSCTL_VNET_PCPUSTAT(_net_inet_ah, IPSECCTL_STATS, stats, struct ahstat, 105 ahstat, "AH statistics (struct ahstat, netipsec/ah_var.h)"); 106#endif 107 108static unsigned char ipseczeroes[256]; /* larger than an ip6 extension hdr */ 109 110static int ah_input_cb(struct cryptop*); 111static int ah_output_cb(struct cryptop*); 112 113static int 114ah_authsize(struct secasvar *sav) 115{ 116 117 IPSEC_ASSERT(sav != NULL, ("%s: sav == NULL", __func__)); 118 119 if (sav->flags & SADB_X_EXT_OLD) 120 return 16; 121 122 switch (sav->alg_auth) { 123 case SADB_X_AALG_SHA2_256: 124 return 16; 125 case SADB_X_AALG_SHA2_384: 126 return 24; 127 case SADB_X_AALG_SHA2_512: 128 return 32; 129 default: 130 return AH_HMAC_HASHLEN; 131 } 132 /* NOTREACHED */ 133} 134/* 135 * NB: this is public for use by the PF_KEY support. 136 */ 137struct auth_hash * 138ah_algorithm_lookup(int alg) 139{ 140 if (alg > SADB_AALG_MAX) 141 return NULL; 142 switch (alg) { 143 case SADB_X_AALG_NULL: 144 return &auth_hash_null; 145 case SADB_AALG_MD5HMAC: 146 return &auth_hash_hmac_md5; 147 case SADB_AALG_SHA1HMAC: 148 return &auth_hash_hmac_sha1; 149 case SADB_X_AALG_RIPEMD160HMAC: 150 return &auth_hash_hmac_ripemd_160; 151 case SADB_X_AALG_MD5: 152 return &auth_hash_key_md5; 153 case SADB_X_AALG_SHA: 154 return &auth_hash_key_sha1; 155 case SADB_X_AALG_SHA2_256: 156 return &auth_hash_hmac_sha2_256; 157 case SADB_X_AALG_SHA2_384: 158 return &auth_hash_hmac_sha2_384; 159 case SADB_X_AALG_SHA2_512: 160 return &auth_hash_hmac_sha2_512; 161 } 162 return NULL; 163} 164 165size_t 166ah_hdrsiz(struct secasvar *sav) 167{ 168 size_t size; 169 170 if (sav != NULL) { 171 int authsize; 172 IPSEC_ASSERT(sav->tdb_authalgxform != NULL, ("null xform")); 173 /*XXX not right for null algorithm--does it matter??*/ 174 authsize = AUTHSIZE(sav); 175 size = roundup(authsize, sizeof (u_int32_t)) + HDRSIZE(sav); 176 } else { 177 /* default guess */ 178 size = sizeof (struct ah) + sizeof (u_int32_t) + 16; 179 } 180 return size; 181} 182 183/* 184 * NB: public for use by esp_init. 185 */ 186int 187ah_init0(struct secasvar *sav, struct xformsw *xsp, struct cryptoini *cria) 188{ 189 struct auth_hash *thash; 190 int keylen; 191 192 thash = ah_algorithm_lookup(sav->alg_auth); 193 if (thash == NULL) { 194 DPRINTF(("%s: unsupported authentication algorithm %u\n", 195 __func__, sav->alg_auth)); 196 return EINVAL; 197 } 198 /* 199 * Verify the replay state block allocation is consistent with 200 * the protocol type. We check here so we can make assumptions 201 * later during protocol processing. 202 */ 203 /* NB: replay state is setup elsewhere (sigh) */ 204 if (((sav->flags&SADB_X_EXT_OLD) == 0) ^ (sav->replay != NULL)) { 205 DPRINTF(("%s: replay state block inconsistency, " 206 "%s algorithm %s replay state\n", __func__, 207 (sav->flags & SADB_X_EXT_OLD) ? "old" : "new", 208 sav->replay == NULL ? "without" : "with")); 209 return EINVAL; 210 } 211 if (sav->key_auth == NULL) { 212 DPRINTF(("%s: no authentication key for %s algorithm\n", 213 __func__, thash->name)); 214 return EINVAL; 215 } 216 keylen = _KEYLEN(sav->key_auth); 217 if (keylen != thash->keysize && thash->keysize != 0) { 218 DPRINTF(("%s: invalid keylength %d, algorithm %s requires " 219 "keysize %d\n", __func__, 220 keylen, thash->name, thash->keysize)); 221 return EINVAL; 222 } 223 224 sav->tdb_xform = xsp; 225 sav->tdb_authalgxform = thash; 226 227 /* Initialize crypto session. */ 228 bzero(cria, sizeof (*cria)); 229 cria->cri_alg = sav->tdb_authalgxform->type; 230 cria->cri_klen = _KEYBITS(sav->key_auth); 231 cria->cri_key = sav->key_auth->key_data; 232 cria->cri_mlen = AUTHSIZE(sav); 233 234 return 0; 235} 236 237/* 238 * ah_init() is called when an SPI is being set up. 239 */ 240static int 241ah_init(struct secasvar *sav, struct xformsw *xsp) 242{ 243 struct cryptoini cria; 244 int error; 245 246 error = ah_init0(sav, xsp, &cria); 247 return error ? error : 248 crypto_newsession(&sav->tdb_cryptoid, &cria, V_crypto_support); 249} 250 251/* 252 * Paranoia. 253 * 254 * NB: public for use by esp_zeroize (XXX). 255 */ 256int 257ah_zeroize(struct secasvar *sav) 258{ 259 int err; 260 261 if (sav->key_auth) 262 bzero(sav->key_auth->key_data, _KEYLEN(sav->key_auth)); 263 264 err = crypto_freesession(sav->tdb_cryptoid); 265 sav->tdb_cryptoid = 0; 266 sav->tdb_authalgxform = NULL; 267 sav->tdb_xform = NULL; 268 return err; 269} 270 271/* 272 * Massage IPv4/IPv6 headers for AH processing. 273 */ 274static int 275ah_massage_headers(struct mbuf **m0, int proto, int skip, int alg, int out) 276{ 277 struct mbuf *m = *m0; 278 unsigned char *ptr; 279 int off, count; 280 281#ifdef INET 282 struct ip *ip; 283#endif /* INET */ 284 285#ifdef INET6 286 struct ip6_ext *ip6e; 287 struct ip6_hdr ip6; 288 int alloc, len, ad; 289#endif /* INET6 */ 290 291 switch (proto) { 292#ifdef INET 293 case AF_INET: 294 /* 295 * This is the least painful way of dealing with IPv4 header 296 * and option processing -- just make sure they're in 297 * contiguous memory. 298 */ 299 *m0 = m = m_pullup(m, skip); 300 if (m == NULL) { 301 DPRINTF(("%s: m_pullup failed\n", __func__)); 302 return ENOBUFS; 303 } 304 305 /* Fix the IP header */ 306 ip = mtod(m, struct ip *); 307 if (V_ah_cleartos) 308 ip->ip_tos = 0; 309 ip->ip_ttl = 0; 310 ip->ip_sum = 0; 311 312 if (alg == CRYPTO_MD5_KPDK || alg == CRYPTO_SHA1_KPDK) 313 ip->ip_off &= htons(IP_DF); 314 else 315 ip->ip_off = htons(0); 316 317 ptr = mtod(m, unsigned char *) + sizeof(struct ip); 318 319 /* IPv4 option processing */ 320 for (off = sizeof(struct ip); off < skip;) { 321 if (ptr[off] == IPOPT_EOL || ptr[off] == IPOPT_NOP || 322 off + 1 < skip) 323 ; 324 else { 325 DPRINTF(("%s: illegal IPv4 option length for " 326 "option %d\n", __func__, ptr[off])); 327 328 m_freem(m); 329 return EINVAL; 330 } 331 332 switch (ptr[off]) { 333 case IPOPT_EOL: 334 off = skip; /* End the loop. */ 335 break; 336 337 case IPOPT_NOP: 338 off++; 339 break; 340 341 case IPOPT_SECURITY: /* 0x82 */ 342 case 0x85: /* Extended security. */ 343 case 0x86: /* Commercial security. */ 344 case 0x94: /* Router alert */ 345 case 0x95: /* RFC1770 */ 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 off += ptr[off + 1]; 357 break; 358 359 case IPOPT_LSRR: 360 case IPOPT_SSRR: 361 /* Sanity check for option length. */ 362 if (ptr[off + 1] < 2) { 363 DPRINTF(("%s: illegal IPv4 option " 364 "length for option %d\n", 365 __func__, ptr[off])); 366 367 m_freem(m); 368 return EINVAL; 369 } 370 371 /* 372 * On output, if we have either of the 373 * source routing options, we should 374 * swap the destination address of the 375 * IP header with the last address 376 * specified in the option, as that is 377 * what the destination's IP header 378 * will look like. 379 */ 380 if (out) 381 bcopy(ptr + off + ptr[off + 1] - 382 sizeof(struct in_addr), 383 &(ip->ip_dst), sizeof(struct in_addr)); 384 385 /* Fall through */ 386 default: 387 /* Sanity check for option length. */ 388 if (ptr[off + 1] < 2) { 389 DPRINTF(("%s: illegal IPv4 option " 390 "length for option %d\n", 391 __func__, ptr[off])); 392 m_freem(m); 393 return EINVAL; 394 } 395 396 /* Zeroize all other options. */ 397 count = ptr[off + 1]; 398 bcopy(ipseczeroes, ptr, count); 399 off += count; 400 break; 401 } 402 403 /* Sanity check. */ 404 if (off > skip) { 405 DPRINTF(("%s: malformed IPv4 options header\n", 406 __func__)); 407 408 m_freem(m); 409 return EINVAL; 410 } 411 } 412 413 break; 414#endif /* INET */ 415 416#ifdef INET6 417 case AF_INET6: /* Ugly... */ 418 /* Copy and "cook" the IPv6 header. */ 419 m_copydata(m, 0, sizeof(ip6), (caddr_t) &ip6); 420 421 /* We don't do IPv6 Jumbograms. */ 422 if (ip6.ip6_plen == 0) { 423 DPRINTF(("%s: unsupported IPv6 jumbogram\n", __func__)); 424 m_freem(m); 425 return EMSGSIZE; 426 } 427 428 ip6.ip6_flow = 0; 429 ip6.ip6_hlim = 0; 430 ip6.ip6_vfc &= ~IPV6_VERSION_MASK; 431 ip6.ip6_vfc |= IPV6_VERSION; 432 433 /* Scoped address handling. */ 434 if (IN6_IS_SCOPE_LINKLOCAL(&ip6.ip6_src)) 435 ip6.ip6_src.s6_addr16[1] = 0; 436 if (IN6_IS_SCOPE_LINKLOCAL(&ip6.ip6_dst)) 437 ip6.ip6_dst.s6_addr16[1] = 0; 438 439 /* Done with IPv6 header. */ 440 m_copyback(m, 0, sizeof(struct ip6_hdr), (caddr_t) &ip6); 441 442 /* Let's deal with the remaining headers (if any). */ 443 if (skip - sizeof(struct ip6_hdr) > 0) { 444 if (m->m_len <= skip) { 445 ptr = (unsigned char *) malloc( 446 skip - sizeof(struct ip6_hdr), 447 M_XDATA, M_NOWAIT); 448 if (ptr == NULL) { 449 DPRINTF(("%s: failed to allocate memory" 450 "for IPv6 headers\n",__func__)); 451 m_freem(m); 452 return ENOBUFS; 453 } 454 455 /* 456 * Copy all the protocol headers after 457 * the IPv6 header. 458 */ 459 m_copydata(m, sizeof(struct ip6_hdr), 460 skip - sizeof(struct ip6_hdr), ptr); 461 alloc = 1; 462 } else { 463 /* No need to allocate memory. */ 464 ptr = mtod(m, unsigned char *) + 465 sizeof(struct ip6_hdr); 466 alloc = 0; 467 } 468 } else 469 break; 470 471 off = ip6.ip6_nxt & 0xff; /* Next header type. */ 472 473 for (len = 0; len < skip - sizeof(struct ip6_hdr);) 474 switch (off) { 475 case IPPROTO_HOPOPTS: 476 case IPPROTO_DSTOPTS: 477 ip6e = (struct ip6_ext *) (ptr + len); 478 479 /* 480 * Process the mutable/immutable 481 * options -- borrows heavily from the 482 * KAME code. 483 */ 484 for (count = len + sizeof(struct ip6_ext); 485 count < len + ((ip6e->ip6e_len + 1) << 3);) { 486 if (ptr[count] == IP6OPT_PAD1) { 487 count++; 488 continue; /* Skip padding. */ 489 } 490 491 /* Sanity check. */ 492 if (count > len + 493 ((ip6e->ip6e_len + 1) << 3)) { 494 m_freem(m); 495 496 /* Free, if we allocated. */ 497 if (alloc) 498 free(ptr, M_XDATA); 499 return EINVAL; 500 } 501 502 ad = ptr[count + 1]; 503 504 /* If mutable option, zeroize. */ 505 if (ptr[count] & IP6OPT_MUTABLE) 506 bcopy(ipseczeroes, ptr + count, 507 ptr[count + 1]); 508 509 count += ad; 510 511 /* Sanity check. */ 512 if (count > 513 skip - sizeof(struct ip6_hdr)) { 514 m_freem(m); 515 516 /* Free, if we allocated. */ 517 if (alloc) 518 free(ptr, M_XDATA); 519 return EINVAL; 520 } 521 } 522 523 /* Advance. */ 524 len += ((ip6e->ip6e_len + 1) << 3); 525 off = ip6e->ip6e_nxt; 526 break; 527 528 case IPPROTO_ROUTING: 529 /* 530 * Always include routing headers in 531 * computation. 532 */ 533 ip6e = (struct ip6_ext *) (ptr + len); 534 len += ((ip6e->ip6e_len + 1) << 3); 535 off = ip6e->ip6e_nxt; 536 break; 537 538 default: 539 DPRINTF(("%s: unexpected IPv6 header type %d", 540 __func__, off)); 541 if (alloc) 542 free(ptr, M_XDATA); 543 m_freem(m); 544 return EINVAL; 545 } 546 547 /* Copyback and free, if we allocated. */ 548 if (alloc) { 549 m_copyback(m, sizeof(struct ip6_hdr), 550 skip - sizeof(struct ip6_hdr), ptr); 551 free(ptr, M_XDATA); 552 } 553 554 break; 555#endif /* INET6 */ 556 } 557 558 return 0; 559} 560 561/* 562 * ah_input() gets called to verify that an input packet 563 * passes authentication. 564 */ 565static int 566ah_input(struct mbuf *m, struct secasvar *sav, int skip, int protoff) 567{ 568 struct auth_hash *ahx; 569 struct tdb_ident *tdbi; 570 struct tdb_crypto *tc; 571 struct m_tag *mtag; 572 struct newah *ah; 573 int hl, rplen, authsize; 574 575 struct cryptodesc *crda; 576 struct cryptop *crp; 577 578 IPSEC_ASSERT(sav != NULL, ("null SA")); 579 IPSEC_ASSERT(sav->key_auth != NULL, ("null authentication key")); 580 IPSEC_ASSERT(sav->tdb_authalgxform != NULL, 581 ("null authentication xform")); 582 583 /* Figure out header size. */ 584 rplen = HDRSIZE(sav); 585 586 /* XXX don't pullup, just copy header */ 587 IP6_EXTHDR_GET(ah, struct newah *, m, skip, rplen); 588 if (ah == NULL) { 589 DPRINTF(("ah_input: cannot pullup header\n")); 590 AHSTAT_INC(ahs_hdrops); /*XXX*/ 591 m_freem(m); 592 return ENOBUFS; 593 } 594 595 /* Check replay window, if applicable. */ 596 if (sav->replay && !ipsec_chkreplay(ntohl(ah->ah_seq), sav)) { 597 AHSTAT_INC(ahs_replay); 598 DPRINTF(("%s: packet replay failure: %s\n", __func__, 599 ipsec_logsastr(sav))); 600 m_freem(m); 601 return ENOBUFS; 602 } 603 604 /* Verify AH header length. */ 605 hl = ah->ah_len * sizeof (u_int32_t); 606 ahx = sav->tdb_authalgxform; 607 authsize = AUTHSIZE(sav); 608 if (hl != authsize + rplen - sizeof (struct ah)) { 609 DPRINTF(("%s: bad authenticator length %u (expecting %lu)" 610 " for packet in SA %s/%08lx\n", __func__, 611 hl, (u_long) (authsize + rplen - sizeof (struct ah)), 612 ipsec_address(&sav->sah->saidx.dst), 613 (u_long) ntohl(sav->spi))); 614 AHSTAT_INC(ahs_badauthl); 615 m_freem(m); 616 return EACCES; 617 } 618 if (skip + authsize + rplen > m->m_pkthdr.len) { 619 DPRINTF(("%s: bad mbuf length %u (expecting %lu)" 620 " for packet in SA %s/%08lx\n", __func__, 621 m->m_pkthdr.len, (u_long) (skip + authsize + rplen), 622 ipsec_address(&sav->sah->saidx.dst, buf, sizeof(buf)), 623 (u_long) ntohl(sav->spi))); 624 AHSTAT_INC(ahs_badauthl); 625 error = EACCES; 626 goto bad; 627 } 628 AHSTAT_ADD(ahs_ibytes, m->m_pkthdr.len - skip - hl); 629 630 /* Get crypto descriptors. */ 631 crp = crypto_getreq(1); 632 if (crp == NULL) { 633 DPRINTF(("%s: failed to acquire crypto descriptor\n",__func__)); 634 AHSTAT_INC(ahs_crypto); 635 m_freem(m); 636 return ENOBUFS; 637 } 638 639 crda = crp->crp_desc; 640 IPSEC_ASSERT(crda != NULL, ("null crypto descriptor")); 641 642 crda->crd_skip = 0; 643 crda->crd_len = m->m_pkthdr.len; 644 crda->crd_inject = skip + rplen; 645 646 /* Authentication operation. */ 647 crda->crd_alg = ahx->type; 648 crda->crd_klen = _KEYBITS(sav->key_auth); 649 crda->crd_key = sav->key_auth->key_data; 650 651 /* Find out if we've already done crypto. */ 652 for (mtag = m_tag_find(m, PACKET_TAG_IPSEC_IN_CRYPTO_DONE, NULL); 653 mtag != NULL; 654 mtag = m_tag_find(m, PACKET_TAG_IPSEC_IN_CRYPTO_DONE, mtag)) { 655 tdbi = (struct tdb_ident *) (mtag + 1); 656 if (tdbi->proto == sav->sah->saidx.proto && 657 tdbi->spi == sav->spi && 658 !bcmp(&tdbi->dst, &sav->sah->saidx.dst, 659 sizeof (union sockaddr_union))) 660 break; 661 } 662 663 /* Allocate IPsec-specific opaque crypto info. */ 664 if (mtag == NULL) { 665 tc = (struct tdb_crypto *) malloc(sizeof (struct tdb_crypto) + 666 skip + rplen + authsize, M_XDATA, M_NOWAIT|M_ZERO); 667 } else { 668 /* Hash verification has already been done successfully. */ 669 tc = (struct tdb_crypto *) malloc(sizeof (struct tdb_crypto), 670 M_XDATA, M_NOWAIT|M_ZERO); 671 } 672 if (tc == NULL) { 673 DPRINTF(("%s: failed to allocate tdb_crypto\n", __func__)); 674 AHSTAT_INC(ahs_crypto); 675 crypto_freereq(crp); 676 m_freem(m); 677 return ENOBUFS; 678 } 679 680 /* Only save information if crypto processing is needed. */ 681 if (mtag == NULL) { 682 int error; 683 684 /* 685 * Save the authenticator, the skipped portion of the packet, 686 * and the AH header. 687 */ 688 m_copydata(m, 0, skip + rplen + authsize, (caddr_t)(tc+1)); 689 690 /* Zeroize the authenticator on the packet. */ 691 m_copyback(m, skip + rplen, authsize, ipseczeroes); 692 693 /* Save ah_nxt, since ah pointer can become invalid after "massage" */ 694 hl = ah->ah_nxt; 695 696 /* "Massage" the packet headers for crypto processing. */ 697 error = ah_massage_headers(&m, sav->sah->saidx.dst.sa.sa_family, 698 skip, ahx->type, 0); 699 if (error != 0) { 700 /* NB: mbuf is free'd by ah_massage_headers */ 701 AHSTAT_INC(ahs_hdrops); 702 free(tc, M_XDATA); 703 crypto_freereq(crp); 704 return error; 705 } 706 } 707 708 /* Crypto operation descriptor. */ 709 crp->crp_ilen = m->m_pkthdr.len; /* Total input length. */ 710 crp->crp_flags = CRYPTO_F_IMBUF | CRYPTO_F_CBIFSYNC; 711 crp->crp_buf = (caddr_t) m; 712 crp->crp_callback = ah_input_cb; 713 crp->crp_sid = sav->tdb_cryptoid; 714 crp->crp_opaque = (caddr_t) tc; 715 716 /* These are passed as-is to the callback. */ 717 tc->tc_spi = sav->spi; 718 tc->tc_dst = sav->sah->saidx.dst; 719 tc->tc_proto = sav->sah->saidx.proto; 720 tc->tc_nxt = hl; 721 tc->tc_protoff = protoff; 722 tc->tc_skip = skip; 723 tc->tc_ptr = (caddr_t) mtag; /* Save the mtag we've identified. */ 724 KEY_ADDREFSA(sav); 725 tc->tc_sav = sav; 726 727 if (mtag == NULL) 728 return crypto_dispatch(crp); 729 else 730 return ah_input_cb(crp); 731} 732 733/* 734 * AH input callback from the crypto driver. 735 */ 736static int 737ah_input_cb(struct cryptop *crp) 738{ 739 int rplen, error, skip, protoff; 740 unsigned char calc[AH_ALEN_MAX]; 741 struct mbuf *m; 742 struct cryptodesc *crd; 743 struct auth_hash *ahx; 744 struct tdb_crypto *tc; 745 struct m_tag *mtag; 746 struct secasvar *sav; 747 struct secasindex *saidx; 748 u_int8_t nxt; 749 caddr_t ptr; 750 int authsize; 751 752 crd = crp->crp_desc; 753 754 tc = (struct tdb_crypto *) crp->crp_opaque; 755 IPSEC_ASSERT(tc != NULL, ("null opaque crypto data area!")); 756 skip = tc->tc_skip; 757 nxt = tc->tc_nxt; 758 protoff = tc->tc_protoff; 759 mtag = (struct m_tag *) tc->tc_ptr; 760 m = (struct mbuf *) crp->crp_buf; 761 762 sav = tc->tc_sav; 763 IPSEC_ASSERT(sav != NULL, ("null SA!")); 764 765 saidx = &sav->sah->saidx; 766 IPSEC_ASSERT(saidx->dst.sa.sa_family == AF_INET || 767 saidx->dst.sa.sa_family == AF_INET6, 768 ("unexpected protocol family %u", saidx->dst.sa.sa_family)); 769 770 ahx = (struct auth_hash *) sav->tdb_authalgxform; 771 772 /* Check for crypto errors. */ 773 if (crp->crp_etype) { 774 if (sav->tdb_cryptoid != 0) 775 sav->tdb_cryptoid = crp->crp_sid; 776 777 if (crp->crp_etype == EAGAIN) 778 return (crypto_dispatch(crp)); 779 780 AHSTAT_INC(ahs_noxform); 781 DPRINTF(("%s: crypto error %d\n", __func__, crp->crp_etype)); 782 error = crp->crp_etype; 783 goto bad; 784 } else { 785 AHSTAT_INC(ahs_hist[sav->alg_auth]); 786 crypto_freereq(crp); /* No longer needed. */ 787 crp = NULL; 788 } 789 790 /* Shouldn't happen... */ 791 if (m == NULL) { 792 AHSTAT_INC(ahs_crypto); 793 DPRINTF(("%s: bogus returned buffer from crypto\n", __func__)); 794 error = EINVAL; 795 goto bad; 796 } 797 798 /* Figure out header size. */ 799 rplen = HDRSIZE(sav); 800 authsize = AUTHSIZE(sav); 801 802 /* Copy authenticator off the packet. */ 803 m_copydata(m, skip + rplen, authsize, calc); 804 805 /* 806 * If we have an mtag, we don't need to verify the authenticator -- 807 * it has been verified by an IPsec-aware NIC. 808 */ 809 if (mtag == NULL) { 810 ptr = (caddr_t) (tc + 1); 811 812 /* Verify authenticator. */ 813 if (bcmp(ptr + skip + rplen, calc, authsize)) { 814 DPRINTF(("%s: authentication hash mismatch for packet " 815 "in SA %s/%08lx\n", __func__, 816 ipsec_address(&saidx->dst), 817 (u_long) ntohl(sav->spi))); 818 AHSTAT_INC(ahs_badauth); 819 error = EACCES; 820 goto bad; 821 } 822 823 /* Fix the Next Protocol field. */ 824 ((u_int8_t *) ptr)[protoff] = nxt; 825 826 /* Copyback the saved (uncooked) network headers. */ 827 m_copyback(m, 0, skip, ptr); 828 } else { 829 /* Fix the Next Protocol field. */ 830 m_copyback(m, protoff, sizeof(u_int8_t), &nxt); 831 } 832 833 free(tc, M_XDATA), tc = NULL; /* No longer needed */ 834 835 /* 836 * Header is now authenticated. 837 */ 838 m->m_flags |= M_AUTHIPHDR|M_AUTHIPDGM; 839 840 /* 841 * Update replay sequence number, if appropriate. 842 */ 843 if (sav->replay) { 844 u_int32_t seq; 845 846 m_copydata(m, skip + offsetof(struct newah, ah_seq), 847 sizeof (seq), (caddr_t) &seq); 848 if (ipsec_updatereplay(ntohl(seq), sav)) { 849 AHSTAT_INC(ahs_replay); 850 error = ENOBUFS; /*XXX as above*/ 851 goto bad; 852 } 853 } 854 855 /* 856 * Remove the AH header and authenticator from the mbuf. 857 */ 858 error = m_striphdr(m, skip, rplen + authsize); 859 if (error) { 860 DPRINTF(("%s: mangled mbuf chain for SA %s/%08lx\n", __func__, 861 ipsec_address(&saidx->dst), (u_long) ntohl(sav->spi))); 862 863 AHSTAT_INC(ahs_hdrops); 864 goto bad; 865 } 866 867 switch (saidx->dst.sa.sa_family) { 868#ifdef INET6 869 case AF_INET6: 870 error = ipsec6_common_input_cb(m, sav, skip, protoff, mtag); 871 break; 872#endif 873#ifdef INET 874 case AF_INET: 875 error = ipsec4_common_input_cb(m, sav, skip, protoff, mtag); 876 break; 877#endif 878 default: 879 panic("%s: Unexpected address family: %d saidx=%p", __func__, 880 saidx->dst.sa.sa_family, saidx); 881 } 882 883 KEY_FREESAV(&sav); 884 return error; 885bad: 886 if (sav) 887 KEY_FREESAV(&sav); 888 if (m != NULL) 889 m_freem(m); 890 if (tc != NULL) 891 free(tc, M_XDATA); 892 if (crp != NULL) 893 crypto_freereq(crp); 894 return error; 895} 896 897/* 898 * AH output routine, called by ipsec[46]_process_packet(). 899 */ 900static int 901ah_output( 902 struct mbuf *m, 903 struct ipsecrequest *isr, 904 struct mbuf **mp, 905 int skip, 906 int protoff) 907{ 908 struct secasvar *sav; 909 struct auth_hash *ahx; 910 struct cryptodesc *crda; 911 struct tdb_crypto *tc; 912 struct mbuf *mi; 913 struct cryptop *crp; 914 u_int16_t iplen; 915 int error, rplen, authsize, maxpacketsize, roff; 916 u_int8_t prot; 917 struct newah *ah; 918 919 sav = isr->sav; 920 IPSEC_ASSERT(sav != NULL, ("null SA")); 921 ahx = sav->tdb_authalgxform; 922 IPSEC_ASSERT(ahx != NULL, ("null authentication xform")); 923 924 AHSTAT_INC(ahs_output); 925 926 /* Figure out header size. */ 927 rplen = HDRSIZE(sav); 928 929 /* Check for maximum packet size violations. */ 930 switch (sav->sah->saidx.dst.sa.sa_family) { 931#ifdef INET 932 case AF_INET: 933 maxpacketsize = IP_MAXPACKET; 934 break; 935#endif /* INET */ 936#ifdef INET6 937 case AF_INET6: 938 maxpacketsize = IPV6_MAXPACKET; 939 break; 940#endif /* INET6 */ 941 default: 942 DPRINTF(("%s: unknown/unsupported protocol family %u, " 943 "SA %s/%08lx\n", __func__, 944 sav->sah->saidx.dst.sa.sa_family, 945 ipsec_address(&sav->sah->saidx.dst), 946 (u_long) ntohl(sav->spi))); 947 AHSTAT_INC(ahs_nopf); 948 error = EPFNOSUPPORT; 949 goto bad; 950 } 951 authsize = AUTHSIZE(sav); 952 if (rplen + authsize + m->m_pkthdr.len > maxpacketsize) { 953 DPRINTF(("%s: packet in SA %s/%08lx got too big " 954 "(len %u, max len %u)\n", __func__, 955 ipsec_address(&sav->sah->saidx.dst), 956 (u_long) ntohl(sav->spi), 957 rplen + authsize + m->m_pkthdr.len, maxpacketsize)); 958 AHSTAT_INC(ahs_toobig); 959 error = EMSGSIZE; 960 goto bad; 961 } 962 963 /* Update the counters. */ 964 AHSTAT_ADD(ahs_obytes, m->m_pkthdr.len - skip); 965 966 m = m_unshare(m, M_NOWAIT); 967 if (m == NULL) { 968 DPRINTF(("%s: cannot clone mbuf chain, SA %s/%08lx\n", __func__, 969 ipsec_address(&sav->sah->saidx.dst), 970 (u_long) ntohl(sav->spi))); 971 AHSTAT_INC(ahs_hdrops); 972 error = ENOBUFS; 973 goto bad; 974 } 975 976 /* Inject AH header. */ 977 mi = m_makespace(m, skip, rplen + authsize, &roff); 978 if (mi == NULL) { 979 DPRINTF(("%s: failed to inject %u byte AH header for SA " 980 "%s/%08lx\n", __func__, 981 rplen + authsize, 982 ipsec_address(&sav->sah->saidx.dst), 983 (u_long) ntohl(sav->spi))); 984 AHSTAT_INC(ahs_hdrops); /*XXX differs from openbsd */ 985 error = ENOBUFS; 986 goto bad; 987 } 988 989 /* 990 * The AH header is guaranteed by m_makespace() to be in 991 * contiguous memory, at roff bytes offset into the returned mbuf. 992 */ 993 ah = (struct newah *)(mtod(mi, caddr_t) + roff); 994 995 /* Initialize the AH header. */ 996 m_copydata(m, protoff, sizeof(u_int8_t), (caddr_t) &ah->ah_nxt); 997 ah->ah_len = (rplen + authsize - sizeof(struct ah)) / sizeof(u_int32_t); 998 ah->ah_reserve = 0; 999 ah->ah_spi = sav->spi; 1000 1001 /* Zeroize authenticator. */ 1002 m_copyback(m, skip + rplen, authsize, ipseczeroes); 1003 1004 /* Insert packet replay counter, as requested. */ 1005 if (sav->replay) { 1006 if (sav->replay->count == ~0 && 1007 (sav->flags & SADB_X_EXT_CYCSEQ) == 0) { 1008 DPRINTF(("%s: replay counter wrapped for SA %s/%08lx\n", 1009 __func__, 1010 ipsec_address(&sav->sah->saidx.dst), 1011 (u_long) ntohl(sav->spi))); 1012 AHSTAT_INC(ahs_wrap); 1013 error = EINVAL; 1014 goto bad; 1015 } 1016#ifdef REGRESSION 1017 /* Emulate replay attack when ipsec_replay is TRUE. */ 1018 if (!V_ipsec_replay) 1019#endif 1020 sav->replay->count++; 1021 ah->ah_seq = htonl(sav->replay->count); 1022 } 1023 1024 /* Get crypto descriptors. */ 1025 crp = crypto_getreq(1); 1026 if (crp == NULL) { 1027 DPRINTF(("%s: failed to acquire crypto descriptors\n", 1028 __func__)); 1029 AHSTAT_INC(ahs_crypto); 1030 error = ENOBUFS; 1031 goto bad; 1032 } 1033 1034 crda = crp->crp_desc; 1035 1036 crda->crd_skip = 0; 1037 crda->crd_inject = skip + rplen; 1038 crda->crd_len = m->m_pkthdr.len; 1039 1040 /* Authentication operation. */ 1041 crda->crd_alg = ahx->type; 1042 crda->crd_key = sav->key_auth->key_data; 1043 crda->crd_klen = _KEYBITS(sav->key_auth); 1044 1045 /* Allocate IPsec-specific opaque crypto info. */ 1046 tc = (struct tdb_crypto *) malloc( 1047 sizeof(struct tdb_crypto) + skip, M_XDATA, M_NOWAIT|M_ZERO); 1048 if (tc == NULL) { 1049 crypto_freereq(crp); 1050 DPRINTF(("%s: failed to allocate tdb_crypto\n", __func__)); 1051 AHSTAT_INC(ahs_crypto); 1052 error = ENOBUFS; 1053 goto bad; 1054 } 1055 1056 /* Save the skipped portion of the packet. */ 1057 m_copydata(m, 0, skip, (caddr_t) (tc + 1)); 1058 1059 /* 1060 * Fix IP header length on the header used for 1061 * authentication. We don't need to fix the original 1062 * header length as it will be fixed by our caller. 1063 */ 1064 switch (sav->sah->saidx.dst.sa.sa_family) { 1065#ifdef INET 1066 case AF_INET: 1067 bcopy(((caddr_t)(tc + 1)) + 1068 offsetof(struct ip, ip_len), 1069 (caddr_t) &iplen, sizeof(u_int16_t)); 1070 iplen = htons(ntohs(iplen) + rplen + authsize); 1071 m_copyback(m, offsetof(struct ip, ip_len), 1072 sizeof(u_int16_t), (caddr_t) &iplen); 1073 break; 1074#endif /* INET */ 1075 1076#ifdef INET6 1077 case AF_INET6: 1078 bcopy(((caddr_t)(tc + 1)) + 1079 offsetof(struct ip6_hdr, ip6_plen), 1080 (caddr_t) &iplen, sizeof(u_int16_t)); 1081 iplen = htons(ntohs(iplen) + rplen + authsize); 1082 m_copyback(m, offsetof(struct ip6_hdr, ip6_plen), 1083 sizeof(u_int16_t), (caddr_t) &iplen); 1084 break; 1085#endif /* INET6 */ 1086 } 1087 1088 /* Fix the Next Header field in saved header. */ 1089 ((u_int8_t *) (tc + 1))[protoff] = IPPROTO_AH; 1090 1091 /* Update the Next Protocol field in the IP header. */ 1092 prot = IPPROTO_AH; 1093 m_copyback(m, protoff, sizeof(u_int8_t), (caddr_t) &prot); 1094 1095 /* "Massage" the packet headers for crypto processing. */ 1096 error = ah_massage_headers(&m, sav->sah->saidx.dst.sa.sa_family, 1097 skip, ahx->type, 1); 1098 if (error != 0) { 1099 m = NULL; /* mbuf was free'd by ah_massage_headers. */ 1100 free(tc, M_XDATA); 1101 crypto_freereq(crp); 1102 goto bad; 1103 } 1104 1105 /* Crypto operation descriptor. */ 1106 crp->crp_ilen = m->m_pkthdr.len; /* Total input length. */ 1107 crp->crp_flags = CRYPTO_F_IMBUF | CRYPTO_F_CBIFSYNC; 1108 crp->crp_buf = (caddr_t) m; 1109 crp->crp_callback = ah_output_cb; 1110 crp->crp_sid = sav->tdb_cryptoid; 1111 crp->crp_opaque = (caddr_t) tc; 1112 1113 /* These are passed as-is to the callback. */ 1114 tc->tc_isr = isr; 1115 KEY_ADDREFSA(sav); 1116 tc->tc_sav = sav; 1117 tc->tc_spi = sav->spi; 1118 tc->tc_dst = sav->sah->saidx.dst; 1119 tc->tc_proto = sav->sah->saidx.proto; 1120 tc->tc_skip = skip; 1121 tc->tc_protoff = protoff; 1122 1123 return crypto_dispatch(crp); 1124bad: 1125 if (m) 1126 m_freem(m); 1127 return (error); 1128} 1129 1130/* 1131 * AH output callback from the crypto driver. 1132 */ 1133static int 1134ah_output_cb(struct cryptop *crp) 1135{ 1136 int skip, protoff, error; 1137 struct tdb_crypto *tc; 1138 struct ipsecrequest *isr; 1139 struct secasvar *sav; 1140 struct mbuf *m; 1141 caddr_t ptr; 1142 1143 tc = (struct tdb_crypto *) crp->crp_opaque; 1144 IPSEC_ASSERT(tc != NULL, ("null opaque data area!")); 1145 skip = tc->tc_skip; 1146 protoff = tc->tc_protoff; 1147 ptr = (caddr_t) (tc + 1); 1148 m = (struct mbuf *) crp->crp_buf; 1149 1150 isr = tc->tc_isr; 1151 IPSECREQUEST_LOCK(isr); 1152 sav = tc->tc_sav; 1153 /* With the isr lock released SA pointer can be updated. */ 1154 if (sav != isr->sav) { 1155 AHSTAT_INC(ahs_notdb); 1156 DPRINTF(("%s: SA expired while in crypto\n", __func__)); 1157 error = ENOBUFS; /*XXX*/ 1158 goto bad; 1159 } 1160 1161 /* Check for crypto errors. */ 1162 if (crp->crp_etype) { 1163 if (sav->tdb_cryptoid != 0) 1164 sav->tdb_cryptoid = crp->crp_sid; 1165 1166 if (crp->crp_etype == EAGAIN) { 1167 IPSECREQUEST_UNLOCK(isr); 1168 return (crypto_dispatch(crp)); 1169 } 1170 1171 AHSTAT_INC(ahs_noxform); 1172 DPRINTF(("%s: crypto error %d\n", __func__, crp->crp_etype)); 1173 error = crp->crp_etype; 1174 goto bad; 1175 } 1176 1177 /* Shouldn't happen... */ 1178 if (m == NULL) { 1179 AHSTAT_INC(ahs_crypto); 1180 DPRINTF(("%s: bogus returned buffer from crypto\n", __func__)); 1181 error = EINVAL; 1182 goto bad; 1183 } 1184 AHSTAT_INC(ahs_hist[sav->alg_auth]); 1185 1186 /* 1187 * Copy original headers (with the new protocol number) back 1188 * in place. 1189 */ 1190 m_copyback(m, 0, skip, ptr); 1191 1192 /* No longer needed. */ 1193 free(tc, M_XDATA); 1194 crypto_freereq(crp); 1195 1196#ifdef REGRESSION 1197 /* Emulate man-in-the-middle attack when ipsec_integrity is TRUE. */ 1198 if (V_ipsec_integrity) { 1199 int alen; 1200 1201 /* 1202 * Corrupt HMAC if we want to test integrity verification of 1203 * the other side. 1204 */ 1205 alen = AUTHSIZE(sav); 1206 m_copyback(m, m->m_pkthdr.len - alen, alen, ipseczeroes); 1207 } 1208#endif 1209 1210 /* NB: m is reclaimed by ipsec_process_done. */ 1211 error = ipsec_process_done(m, isr); 1212 KEY_FREESAV(&sav); 1213 IPSECREQUEST_UNLOCK(isr); 1214 return error; 1215bad: 1216 if (sav) 1217 KEY_FREESAV(&sav); 1218 IPSECREQUEST_UNLOCK(isr); 1219 if (m) 1220 m_freem(m); 1221 free(tc, M_XDATA); 1222 crypto_freereq(crp); 1223 return error; 1224} 1225 1226static struct xformsw ah_xformsw = { 1227 XF_AH, XFT_AUTH, "IPsec AH", 1228 ah_init, ah_zeroize, ah_input, ah_output, 1229}; 1230 1231static void 1232ah_attach(void) 1233{ 1234 1235 xform_register(&ah_xformsw); 1236} 1237 1238SYSINIT(ah_xform_init, SI_SUB_PROTO_DOMAIN, SI_ORDER_MIDDLE, ah_attach, NULL); 1239