sys/netinet6/ah_input.c

   1 /*      $FreeBSD: src/sys/netinet6/ah_input.c,v 1.1.2.6 2002/04/28 05:40:26 suz Exp $   */
   2 /*      $DragonFly: src/sys/netinet6/ah_input.c,v 1.3 2003/07/23 02:30:22 dillon Exp $  */
   3 /*      $KAME: ah_input.c,v 1.67 2002/01/07 11:39:56 kjc Exp $  */
   4
   5 /*
   6  * Copyright (C) 1995, 1996, 1997, and 1998 WIDE Project.
   7  * All rights reserved.
   8  *
   9  * Redistribution and use in source and binary forms, with or without
  10  * modification, are permitted provided that the following conditions
  11  * are met:
  12  * 1. Redistributions of source code must retain the above copyright
  13  *    notice, this list of conditions and the following disclaimer.
  14  * 2. Redistributions in binary form must reproduce the above copyright
  15  *    notice, this list of conditions and the following disclaimer in the
  16  *    documentation and/or other materials provided with the distribution.
  17  * 3. Neither the name of the project nor the names of its contributors
  18  *    may be used to endorse or promote products derived from this software
  19  *    without specific prior written permission.
  20  *
  21  * THIS SOFTWARE IS PROVIDED BY THE PROJECT AND CONTRIBUTORS ``AS IS'' AND
  22  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  23  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  24  * ARE DISCLAIMED.  IN NO EVENT SHALL THE PROJECT OR CONTRIBUTORS BE LIABLE
  25  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  26  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  27  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  28  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  29  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  30  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  31  * SUCH DAMAGE.
  32  */
  33
  34 /*
  35  * RFC1826/2402 authentication header.
  36  */
  37
  38 #include "opt_inet.h"
  39 #include "opt_inet6.h"
  40
  41 #include <sys/param.h>
  42 #include <sys/systm.h>
  43 #include <sys/malloc.h>
  44 #include <sys/mbuf.h>
  45 #include <sys/domain.h>
  46 #include <sys/protosw.h>
  47 #include <sys/socket.h>
  48 #include <sys/errno.h>
  49 #include <sys/time.h>
  50 #include <sys/syslog.h>
  51
  52 #include <net/if.h>
  53 #include <net/route.h>
  54 #include <net/netisr.h>
  55 #include <machine/cpu.h>
  56
  57 #include <netinet/in.h>
  58 #include <netinet/in_systm.h>
  59 #include <netinet/in_var.h>
  60 #include <netinet/ip.h>
  61 #include <netinet/ip_var.h>
  62 #include <netinet/ip_ecn.h>
  63 #ifdef INET6
  64 #include <netinet6/ip6_ecn.h>
  65 #endif
  66
  67 #ifdef INET6
  68 #include <netinet/ip6.h>
  69 #include <netinet6/ip6_var.h>
  70 #include <netinet6/in6_pcb.h>
  71 #include <netinet/icmp6.h>
  72 #include <netinet6/ip6protosw.h>
  73 #endif
  74
  75 #include <netinet6/ipsec.h>
  76 #ifdef INET6
  77 #include <netinet6/ipsec6.h>
  78 #endif
  79 #include <netinet6/ah.h>
  80 #ifdef INET6
  81 #include <netinet6/ah6.h>
  82 #endif
  83 #include <netkey/key.h>
  84 #include <netkey/keydb.h>
  85 #ifdef IPSEC_DEBUG
  86 #include <netkey/key_debug.h>
  87 #else
  88 #define KEYDEBUG(lev,arg)
  89 #endif
  90
  91 #include <machine/stdarg.h>
  92
  93 #include <net/net_osdep.h>
  94
  95 #define IPLEN_FLIPPED
  96
  97 #ifdef INET
  98 #include <netinet/ipprotosw.h>
  99 extern struct ipprotosw inetsw[];
 100
 101 void
 102 ah4_input(struct mbuf *m, int off, int proto)
 103 {
 104         struct ip *ip;
 105         struct ah *ah;
 106         u_int32_t spi;
 107         const struct ah_algorithm *algo;
 108         size_t siz;
 109         size_t siz1;
 110         u_char *cksum;
 111         struct secasvar *sav = NULL;
 112         u_int16_t nxt;
 113         size_t hlen;
 114         int s;
 115         size_t stripsiz = 0;
 116
 117 #ifndef PULLDOWN_TEST
 118         if (m->m_len < off + sizeof(struct newah)) {
 119                 m = m_pullup(m, off + sizeof(struct newah));
 120                 if (!m) {
 121                         ipseclog((LOG_DEBUG, "IPv4 AH input: can't pullup;"
 122                                 "dropping the packet for simplicity\n"));
 123                         ipsecstat.in_inval++;
 124                         goto fail;
 125                 }
 126         }
 127
 128         ip = mtod(m, struct ip *);
 129         ah = (struct ah *)(((caddr_t)ip) + off);
 130 #else
 131         ip = mtod(m, struct ip *);
 132         IP6_EXTHDR_GET(ah, struct ah *, m, off, sizeof(struct newah));
 133         if (ah == NULL) {
 134                 ipseclog((LOG_DEBUG, "IPv4 AH input: can't pullup;"
 135                         "dropping the packet for simplicity\n"));
 136                 ipsecstat.in_inval++;
 137                 goto fail;
 138         }
 139 #endif
 140         nxt = ah->ah_nxt;
 141 #ifdef _IP_VHL
 142         hlen = IP_VHL_HL(ip->ip_vhl) << 2;
 143 #else
 144         hlen = ip->ip_hl << 2;
 145 #endif
 146
 147         /* find the sassoc. */
 148         spi = ah->ah_spi;
 149
 150         if ((sav = key_allocsa(AF_INET,
 151                               (caddr_t)&ip->ip_src, (caddr_t)&ip->ip_dst,
 152                               IPPROTO_AH, spi)) == 0) {
 153                 ipseclog((LOG_WARNING,
 154                     "IPv4 AH input: no key association found for spi %u\n",
 155                     (u_int32_t)ntohl(spi)));
 156                 ipsecstat.in_nosa++;
 157                 goto fail;
 158         }
 159         KEYDEBUG(KEYDEBUG_IPSEC_STAMP,
 160                 printf("DP ah4_input called to allocate SA:%p\n", sav));
 161         if (sav->state != SADB_SASTATE_MATURE
 162          && sav->state != SADB_SASTATE_DYING) {
 163                 ipseclog((LOG_DEBUG,
 164                     "IPv4 AH input: non-mature/dying SA found for spi %u\n",
 165                     (u_int32_t)ntohl(spi)));
 166                 ipsecstat.in_badspi++;
 167                 goto fail;
 168         }
 169
 170         algo = ah_algorithm_lookup(sav->alg_auth);
 171         if (!algo) {
 172                 ipseclog((LOG_DEBUG, "IPv4 AH input: "
 173                     "unsupported authentication algorithm for spi %u\n",
 174                     (u_int32_t)ntohl(spi)));
 175                 ipsecstat.in_badspi++;
 176                 goto fail;
 177         }
 178
 179         siz = (*algo->sumsiz)(sav);
 180         siz1 = ((siz + 3) & ~(4 - 1));
 181
 182         /*
 183          * sanity checks for header, 1.
 184          */
 185     {
 186         int sizoff;
 187
 188         sizoff = (sav->flags & SADB_X_EXT_OLD) ? 0 : 4;
 189
 190         /*
 191          * Here, we do not do "siz1 == siz".  This is because the way
 192          * RFC240[34] section 2 is written.  They do not require truncation
 193          * to 96 bits.
 194          * For example, Microsoft IPsec stack attaches 160 bits of
 195          * authentication data for both hmac-md5 and hmac-sha1.  For hmac-sha1,
 196          * 32 bits of padding is attached.
 197          *
 198          * There are two downsides to this specification.
 199          * They have no real harm, however, they leave us fuzzy feeling.
 200          * - if we attach more than 96 bits of authentication data onto AH,
 201          *   we will never notice about possible modification by rogue
 202          *   intermediate nodes.
 203          *   Since extra bits in AH checksum is never used, this constitutes
 204          *   no real issue, however, it is wacky.
 205          * - even if the peer attaches big authentication data, we will never
 206          *   notice the difference, since longer authentication data will just
 207          *   work.
 208          *
 209          * We may need some clarification in the spec.
 210          */
 211         if (siz1 < siz) {
 212                 ipseclog((LOG_NOTICE, "sum length too short in IPv4 AH input "
 213                     "(%lu, should be at least %lu): %s\n",
 214                     (u_long)siz1, (u_long)siz,
 215                     ipsec4_logpacketstr(ip, spi)));
 216                 ipsecstat.in_inval++;
 217                 goto fail;
 218         }
 219         if ((ah->ah_len << 2) - sizoff != siz1) {
 220                 ipseclog((LOG_NOTICE, "sum length mismatch in IPv4 AH input "
 221                     "(%d should be %lu): %s\n",
 222                     (ah->ah_len << 2) - sizoff, (u_long)siz1,
 223                     ipsec4_logpacketstr(ip, spi)));
 224                 ipsecstat.in_inval++;
 225                 goto fail;
 226         }
 227
 228 #ifndef PULLDOWN_TEST
 229         if (m->m_len < off + sizeof(struct ah) + sizoff + siz1) {
 230                 m = m_pullup(m, off + sizeof(struct ah) + sizoff + siz1);
 231                 if (!m) {
 232                         ipseclog((LOG_DEBUG, "IPv4 AH input: can't pullup\n"));
 233                         ipsecstat.in_inval++;
 234                         goto fail;
 235                 }
 236
 237                 ip = mtod(m, struct ip *);
 238                 ah = (struct ah *)(((caddr_t)ip) + off);
 239         }
 240 #else
 241         IP6_EXTHDR_GET(ah, struct ah *, m, off,
 242                 sizeof(struct ah) + sizoff + siz1);
 243         if (ah == NULL) {
 244                 ipseclog((LOG_DEBUG, "IPv4 AH input: can't pullup\n"));
 245                 ipsecstat.in_inval++;
 246                 goto fail;
 247         }
 248 #endif
 249     }
 250
 251         /*
 252          * check for sequence number.
 253          */
 254         if ((sav->flags & SADB_X_EXT_OLD) == 0 && sav->replay) {
 255                 if (ipsec_chkreplay(ntohl(((struct newah *)ah)->ah_seq), sav))
 256                         ; /* okey */
 257                 else {
 258                         ipsecstat.in_ahreplay++;
 259                         ipseclog((LOG_WARNING,
 260                             "replay packet in IPv4 AH input: %s %s\n",
 261                             ipsec4_logpacketstr(ip, spi), ipsec_logsastr(sav)));
 262                         goto fail;
 263                 }
 264         }
 265
 266         /*
 267          * alright, it seems sane.  now we are going to check the
 268          * cryptographic checksum.
 269          */
 270         cksum = malloc(siz1, M_TEMP, M_NOWAIT);
 271         if (!cksum) {
 272                 ipseclog((LOG_DEBUG, "IPv4 AH input: "
 273                     "couldn't alloc temporary region for cksum\n"));
 274                 ipsecstat.in_inval++;
 275                 goto fail;
 276         }
 277
 278         /*
 279          * some of IP header fields are flipped to the host endian.
 280          * convert them back to network endian.  VERY stupid.
 281          */
 282         ip->ip_len = htons(ip->ip_len + hlen);
 283         ip->ip_off = htons(ip->ip_off);
 284         if (ah4_calccksum(m, (caddr_t)cksum, siz1, algo, sav)) {
 285                 free(cksum, M_TEMP);
 286                 ipsecstat.in_inval++;
 287                 goto fail;
 288         }
 289         ipsecstat.in_ahhist[sav->alg_auth]++;
 290         /*
 291          * flip them back.
 292          */
 293         ip->ip_len = ntohs(ip->ip_len) - hlen;
 294         ip->ip_off = ntohs(ip->ip_off);
 295
 296     {
 297         caddr_t sumpos = NULL;
 298
 299         if (sav->flags & SADB_X_EXT_OLD) {
 300                 /* RFC 1826 */
 301                 sumpos = (caddr_t)(ah + 1);
 302         } else {
 303                 /* RFC 2402 */
 304                 sumpos = (caddr_t)(((struct newah *)ah) + 1);
 305         }
 306
 307         if (bcmp(sumpos, cksum, siz) != 0) {
 308                 ipseclog((LOG_WARNING,
 309                     "checksum mismatch in IPv4 AH input: %s %s\n",
 310                     ipsec4_logpacketstr(ip, spi), ipsec_logsastr(sav)));
 311                 free(cksum, M_TEMP);
 312                 ipsecstat.in_ahauthfail++;
 313                 goto fail;
 314         }
 315     }
 316
 317         free(cksum, M_TEMP);
 318
 319         m->m_flags |= M_AUTHIPHDR;
 320         m->m_flags |= M_AUTHIPDGM;
 321
 322 #if 0
 323         /*
 324          * looks okey, but we need more sanity check.
 325          * XXX should elaborate.
 326          */
 327         if (ah->ah_nxt == IPPROTO_IPIP || ah->ah_nxt == IPPROTO_IP) {
 328                 struct ip *nip;
 329                 size_t sizoff;
 330
 331                 sizoff = (sav->flags & SADB_X_EXT_OLD) ? 0 : 4;
 332
 333                 if (m->m_len < off + sizeof(struct ah) + sizoff + siz1 + hlen) {
 334                         m = m_pullup(m, off + sizeof(struct ah)
 335                                         + sizoff + siz1 + hlen);
 336                         if (!m) {
 337                                 ipseclog((LOG_DEBUG,
 338                                     "IPv4 AH input: can't pullup\n"));
 339                                 ipsecstat.in_inval++;
 340                                 goto fail;
 341                         }
 342                 }
 343
 344                 nip = (struct ip *)((u_char *)(ah + 1) + sizoff + siz1);
 345                 if (nip->ip_src.s_addr != ip->ip_src.s_addr
 346                  || nip->ip_dst.s_addr != ip->ip_dst.s_addr) {
 347                         m->m_flags &= ~M_AUTHIPHDR;
 348                         m->m_flags &= ~M_AUTHIPDGM;
 349                 }
 350         }
 351 #ifdef INET6
 352         else if (ah->ah_nxt == IPPROTO_IPV6) {
 353                 m->m_flags &= ~M_AUTHIPHDR;
 354                 m->m_flags &= ~M_AUTHIPDGM;
 355         }
 356 #endif /* INET6 */
 357 #endif /* 0 */
 358
 359         if (m->m_flags & M_AUTHIPHDR
 360          && m->m_flags & M_AUTHIPDGM) {
 361 #if 0
 362                 ipseclog((LOG_DEBUG,
 363                     "IPv4 AH input: authentication succeess\n"));
 364 #endif
 365                 ipsecstat.in_ahauthsucc++;
 366         } else {
 367                 ipseclog((LOG_WARNING,
 368                     "authentication failed in IPv4 AH input: %s %s\n",
 369                     ipsec4_logpacketstr(ip, spi), ipsec_logsastr(sav)));
 370                 ipsecstat.in_ahauthfail++;
 371                 goto fail;
 372         }
 373
 374         /*
 375          * update sequence number.
 376          */
 377         if ((sav->flags & SADB_X_EXT_OLD) == 0 && sav->replay) {
 378                 if (ipsec_updatereplay(ntohl(((struct newah *)ah)->ah_seq), sav)) {
 379                         ipsecstat.in_ahreplay++;
 380                         goto fail;
 381                 }
 382         }
 383
 384         /* was it transmitted over the IPsec tunnel SA? */
 385         if (sav->flags & SADB_X_EXT_OLD) {
 386                 /* RFC 1826 */
 387                 stripsiz = sizeof(struct ah) + siz1;
 388         } else {
 389                 /* RFC 2402 */
 390                 stripsiz = sizeof(struct newah) + siz1;
 391         }
 392         if (ipsec4_tunnel_validate(m, off + stripsiz, nxt, sav)) {
 393                 /*
 394                  * strip off all the headers that precedes AH.
 395                  *      IP xx AH IP' payload -> IP' payload
 396                  *
 397                  * XXX more sanity checks
 398                  * XXX relationship with gif?
 399                  */
 400                 u_int8_t tos;
 401
 402                 tos = ip->ip_tos;
 403                 m_adj(m, off + stripsiz);
 404                 if (m->m_len < sizeof(*ip)) {
 405                         m = m_pullup(m, sizeof(*ip));
 406                         if (!m) {
 407                                 ipsecstat.in_inval++;
 408                                 goto fail;
 409                         }
 410                 }
 411                 ip = mtod(m, struct ip *);
 412                 /* ECN consideration. */
 413                 ip_ecn_egress(ip4_ipsec_ecn, &tos, &ip->ip_tos);
 414                 if (!key_checktunnelsanity(sav, AF_INET,
 415                             (caddr_t)&ip->ip_src, (caddr_t)&ip->ip_dst)) {
 416                         ipseclog((LOG_NOTICE, "ipsec tunnel address mismatch "
 417                             "in IPv4 AH input: %s %s\n",
 418                             ipsec4_logpacketstr(ip, spi), ipsec_logsastr(sav)));
 419                         ipsecstat.in_inval++;
 420                         goto fail;
 421                 }
 422
 423 #if 1
 424                 /*
 425                  * Should the inner packet be considered authentic?
 426                  * My current answer is: NO.
 427                  *
 428                  * host1 -- gw1 === gw2 -- host2
 429                  *      In this case, gw2 can trust the authenticity of the
 430                  *      outer packet, but NOT inner.  Packet may be altered
 431                  *      between host1 and gw1.
 432                  *
 433                  * host1 -- gw1 === host2
 434                  *      This case falls into the same scenario as above.
 435                  *
 436                  * host1 === host2
 437                  *      This case is the only case when we may be able to leave
 438                  *      M_AUTHIPHDR and M_AUTHIPDGM set.
 439                  *      However, if host1 is wrongly configured, and allows
 440                  *      attacker to inject some packet with src=host1 and
 441                  *      dst=host2, you are in risk.
 442                  */
 443                 m->m_flags &= ~M_AUTHIPHDR;
 444                 m->m_flags &= ~M_AUTHIPDGM;
 445 #endif
 446
 447                 key_sa_recordxfer(sav, m);
 448                 if (ipsec_addhist(m, IPPROTO_AH, spi) != 0 ||
 449                     ipsec_addhist(m, IPPROTO_IPV4, 0) != 0) {
 450                         ipsecstat.in_nomem++;
 451                         goto fail;
 452                 }
 453
 454                 s = splimp();
 455                 if (IF_QFULL(&ipintrq)) {
 456                         ipsecstat.in_inval++;
 457                         splx(s);
 458                         goto fail;
 459                 }
 460                 IF_ENQUEUE(&ipintrq, m);
 461                 m = NULL;
 462                 schednetisr(NETISR_IP); /* can be skipped but to make sure */
 463                 splx(s);
 464                 nxt = IPPROTO_DONE;
 465         } else {
 466                 /*
 467                  * strip off AH.
 468                  */
 469
 470                 ip = mtod(m, struct ip *);
 471 #ifndef PULLDOWN_TEST
 472                 /*
 473                  * We do deep-copy since KAME requires that
 474                  * the packet is placed in a single external mbuf.
 475                  */
 476                 ovbcopy((caddr_t)ip, (caddr_t)(((u_char *)ip) + stripsiz), off);
 477                 m->m_data += stripsiz;
 478                 m->m_len -= stripsiz;
 479                 m->m_pkthdr.len -= stripsiz;
 480 #else
 481                 /*
 482                  * even in m_pulldown case, we need to strip off AH so that
 483                  * we can compute checksum for multiple AH correctly.
 484                  */
 485                 if (m->m_len >= stripsiz + off) {
 486                         ovbcopy((caddr_t)ip, ((caddr_t)ip) + stripsiz, off);
 487                         m->m_data += stripsiz;
 488                         m->m_len -= stripsiz;
 489                         m->m_pkthdr.len -= stripsiz;
 490                 } else {
 491                         /*
 492                          * this comes with no copy if the boundary is on
 493                          * cluster
 494                          */
 495                         struct mbuf *n;
 496
 497                         n = m_split(m, off, M_DONTWAIT);
 498                         if (n == NULL) {
 499                                 /* m is retained by m_split */
 500                                 goto fail;
 501                         }
 502                         m_adj(n, stripsiz);
 503                         m_cat(m, n);
 504                         /* m_cat does not update m_pkthdr.len */
 505                         m->m_pkthdr.len += n->m_pkthdr.len;
 506                 }
 507 #endif
 508
 509                 if (m->m_len < sizeof(*ip)) {
 510                         m = m_pullup(m, sizeof(*ip));
 511                         if (m == NULL) {
 512                                 ipsecstat.in_inval++;
 513                                 goto fail;
 514                         }
 515                 }
 516                 ip = mtod(m, struct ip *);
 517 #ifdef IPLEN_FLIPPED
 518                 ip->ip_len = ip->ip_len - stripsiz;
 519 #else
 520                 ip->ip_len = htons(ntohs(ip->ip_len) - stripsiz);
 521 #endif
 522                 ip->ip_p = nxt;
 523                 /* forget about IP hdr checksum, the check has already been passed */
 524
 525                 key_sa_recordxfer(sav, m);
 526                 if (ipsec_addhist(m, IPPROTO_AH, spi) != 0) {
 527                         ipsecstat.in_nomem++;
 528                         goto fail;
 529                 }
 530
 531                 if (nxt != IPPROTO_DONE) {
 532                         if ((inetsw[ip_protox[nxt]].pr_flags & PR_LASTHDR) != 0 &&
 533                             ipsec4_in_reject(m, NULL)) {
 534                                 ipsecstat.in_polvio++;
 535                                 goto fail;
 536                         }
 537                         (*inetsw[ip_protox[nxt]].pr_input)(m, off, nxt);
 538                 } else
 539                         m_freem(m);
 540                 m = NULL;
 541         }
 542
 543         if (sav) {
 544                 KEYDEBUG(KEYDEBUG_IPSEC_STAMP,
 545                         printf("DP ah4_input call free SA:%p\n", sav));
 546                 key_freesav(sav);
 547         }
 548         ipsecstat.in_success++;
 549         return;
 550
 551 fail:
 552         if (sav) {
 553                 KEYDEBUG(KEYDEBUG_IPSEC_STAMP,
 554                         printf("DP ah4_input call free SA:%p\n", sav));
 555                 key_freesav(sav);
 556         }
 557         if (m)
 558                 m_freem(m);
 559         return;
 560 }
 561 #endif /* INET */
 562
 563 #ifdef INET6
 564 int
 565 ah6_input(mp, offp, proto)
 566         struct mbuf **mp;
 567         int *offp, proto;
 568 {
 569         struct mbuf *m = *mp;
 570         int off = *offp;
 571         struct ip6_hdr *ip6;
 572         struct ah *ah;
 573         u_int32_t spi;
 574         const struct ah_algorithm *algo;
 575         size_t siz;
 576         size_t siz1;
 577         u_char *cksum;
 578         struct secasvar *sav = NULL;
 579         u_int16_t nxt;
 580         int s;
 581         size_t stripsiz = 0;
 582
 583 #ifndef PULLDOWN_TEST
 584         IP6_EXTHDR_CHECK(m, off, sizeof(struct ah), IPPROTO_DONE);
 585         ah = (struct ah *)(mtod(m, caddr_t) + off);
 586 #else
 587         IP6_EXTHDR_GET(ah, struct ah *, m, off, sizeof(struct newah));
 588         if (ah == NULL) {
 589                 ipseclog((LOG_DEBUG, "IPv6 AH input: can't pullup\n"));
 590                 ipsec6stat.in_inval++;
 591                 return IPPROTO_DONE;
 592         }
 593 #endif
 594         ip6 = mtod(m, struct ip6_hdr *);
 595         nxt = ah->ah_nxt;
 596
 597         /* find the sassoc. */
 598         spi = ah->ah_spi;
 599
 600         if (ntohs(ip6->ip6_plen) == 0) {
 601                 ipseclog((LOG_ERR, "IPv6 AH input: "
 602                     "AH with IPv6 jumbogram is not supported.\n"));
 603                 ipsec6stat.in_inval++;
 604                 goto fail;
 605         }
 606
 607         if ((sav = key_allocsa(AF_INET6,
 608                               (caddr_t)&ip6->ip6_src, (caddr_t)&ip6->ip6_dst,
 609                               IPPROTO_AH, spi)) == 0) {
 610                 ipseclog((LOG_WARNING,
 611                     "IPv6 AH input: no key association found for spi %u\n",
 612                     (u_int32_t)ntohl(spi)));
 613                 ipsec6stat.in_nosa++;
 614                 goto fail;
 615         }
 616         KEYDEBUG(KEYDEBUG_IPSEC_STAMP,
 617                 printf("DP ah6_input called to allocate SA:%p\n", sav));
 618         if (sav->state != SADB_SASTATE_MATURE
 619          && sav->state != SADB_SASTATE_DYING) {
 620                 ipseclog((LOG_DEBUG,
 621                     "IPv6 AH input: non-mature/dying SA found for spi %u; ",
 622                     (u_int32_t)ntohl(spi)));
 623                 ipsec6stat.in_badspi++;
 624                 goto fail;
 625         }
 626
 627         algo = ah_algorithm_lookup(sav->alg_auth);
 628         if (!algo) {
 629                 ipseclog((LOG_DEBUG, "IPv6 AH input: "
 630                     "unsupported authentication algorithm for spi %u\n",
 631                     (u_int32_t)ntohl(spi)));
 632                 ipsec6stat.in_badspi++;
 633                 goto fail;
 634         }
 635
 636         siz = (*algo->sumsiz)(sav);
 637         siz1 = ((siz + 3) & ~(4 - 1));
 638
 639         /*
 640          * sanity checks for header, 1.
 641          */
 642     {
 643         int sizoff;
 644
 645         sizoff = (sav->flags & SADB_X_EXT_OLD) ? 0 : 4;
 646
 647         /*
 648          * Here, we do not do "siz1 == siz".  See ah4_input() for complete
 649          * description.
 650          */
 651         if (siz1 < siz) {
 652                 ipseclog((LOG_NOTICE, "sum length too short in IPv6 AH input "
 653                     "(%lu, should be at least %lu): %s\n",
 654                     (u_long)siz1, (u_long)siz,
 655                     ipsec6_logpacketstr(ip6, spi)));
 656                 ipsec6stat.in_inval++;
 657                 goto fail;
 658         }
 659         if ((ah->ah_len << 2) - sizoff != siz1) {
 660                 ipseclog((LOG_NOTICE, "sum length mismatch in IPv6 AH input "
 661                     "(%d should be %lu): %s\n",
 662                     (ah->ah_len << 2) - sizoff, (u_long)siz1,
 663                     ipsec6_logpacketstr(ip6, spi)));
 664                 ipsec6stat.in_inval++;
 665                 goto fail;
 666         }
 667 #ifndef PULLDOWN_TEST
 668         IP6_EXTHDR_CHECK(m, off, sizeof(struct ah) + sizoff + siz1, IPPROTO_DONE);
 669 #else
 670         IP6_EXTHDR_GET(ah, struct ah *, m, off,
 671                 sizeof(struct ah) + sizoff + siz1);
 672         if (ah == NULL) {
 673                 ipseclog((LOG_NOTICE, "couldn't pullup gather IPv6 AH checksum part"));
 674                 ipsec6stat.in_inval++;
 675                 m = NULL;
 676                 goto fail;
 677         }
 678 #endif
 679     }
 680
 681         /*
 682          * check for sequence number.
 683          */
 684         if ((sav->flags & SADB_X_EXT_OLD) == 0 && sav->replay) {
 685                 if (ipsec_chkreplay(ntohl(((struct newah *)ah)->ah_seq), sav))
 686                         ; /* okey */
 687                 else {
 688                         ipsec6stat.in_ahreplay++;
 689                         ipseclog((LOG_WARNING,
 690                             "replay packet in IPv6 AH input: %s %s\n",
 691                             ipsec6_logpacketstr(ip6, spi),
 692                             ipsec_logsastr(sav)));
 693                         goto fail;
 694                 }
 695         }
 696
 697         /*
 698          * alright, it seems sane.  now we are going to check the
 699          * cryptographic checksum.
 700          */
 701         cksum = malloc(siz1, M_TEMP, M_NOWAIT);
 702         if (!cksum) {
 703                 ipseclog((LOG_DEBUG, "IPv6 AH input: "
 704                     "couldn't alloc temporary region for cksum\n"));
 705                 ipsec6stat.in_inval++;
 706                 goto fail;
 707         }
 708
 709         if (ah6_calccksum(m, (caddr_t)cksum, siz1, algo, sav)) {
 710                 free(cksum, M_TEMP);
 711                 ipsec6stat.in_inval++;
 712                 goto fail;
 713         }
 714         ipsec6stat.in_ahhist[sav->alg_auth]++;
 715
 716     {
 717         caddr_t sumpos = NULL;
 718
 719         if (sav->flags & SADB_X_EXT_OLD) {
 720                 /* RFC 1826 */
 721                 sumpos = (caddr_t)(ah + 1);
 722         } else {
 723                 /* RFC 2402 */
 724                 sumpos = (caddr_t)(((struct newah *)ah) + 1);
 725         }
 726
 727         if (bcmp(sumpos, cksum, siz) != 0) {
 728                 ipseclog((LOG_WARNING,
 729                     "checksum mismatch in IPv6 AH input: %s %s\n",
 730                     ipsec6_logpacketstr(ip6, spi), ipsec_logsastr(sav)));
 731                 free(cksum, M_TEMP);
 732                 ipsec6stat.in_ahauthfail++;
 733                 goto fail;
 734         }
 735     }
 736
 737         free(cksum, M_TEMP);
 738
 739         m->m_flags |= M_AUTHIPHDR;
 740         m->m_flags |= M_AUTHIPDGM;
 741
 742 #if 0
 743         /*
 744          * looks okey, but we need more sanity check.
 745          * XXX should elaborate.
 746          */
 747         if (ah->ah_nxt == IPPROTO_IPV6) {
 748                 struct ip6_hdr *nip6;
 749                 size_t sizoff;
 750
 751                 sizoff = (sav->flags & SADB_X_EXT_OLD) ? 0 : 4;
 752
 753                 IP6_EXTHDR_CHECK(m, off, sizeof(struct ah) + sizoff + siz1
 754                                 + sizeof(struct ip6_hdr), IPPROTO_DONE);
 755
 756                 nip6 = (struct ip6_hdr *)((u_char *)(ah + 1) + sizoff + siz1);
 757                 if (!IN6_ARE_ADDR_EQUAL(&nip6->ip6_src, &ip6->ip6_src)
 758                  || !IN6_ARE_ADDR_EQUAL(&nip6->ip6_dst, &ip6->ip6_dst)) {
 759                         m->m_flags &= ~M_AUTHIPHDR;
 760                         m->m_flags &= ~M_AUTHIPDGM;
 761                 }
 762         } else if (ah->ah_nxt == IPPROTO_IPIP) {
 763                 m->m_flags &= ~M_AUTHIPHDR;
 764                 m->m_flags &= ~M_AUTHIPDGM;
 765         } else if (ah->ah_nxt == IPPROTO_IP) {
 766                 m->m_flags &= ~M_AUTHIPHDR;
 767                 m->m_flags &= ~M_AUTHIPDGM;
 768         }
 769 #endif
 770
 771         if (m->m_flags & M_AUTHIPHDR
 772          && m->m_flags & M_AUTHIPDGM) {
 773 #if 0
 774                 ipseclog((LOG_DEBUG,
 775                     "IPv6 AH input: authentication succeess\n"));
 776 #endif
 777                 ipsec6stat.in_ahauthsucc++;
 778         } else {
 779                 ipseclog((LOG_WARNING,
 780                     "authentication failed in IPv6 AH input: %s %s\n",
 781                     ipsec6_logpacketstr(ip6, spi), ipsec_logsastr(sav)));
 782                 ipsec6stat.in_ahauthfail++;
 783                 goto fail;
 784         }
 785
 786         /*
 787          * update sequence number.
 788          */
 789         if ((sav->flags & SADB_X_EXT_OLD) == 0 && sav->replay) {
 790                 if (ipsec_updatereplay(ntohl(((struct newah *)ah)->ah_seq), sav)) {
 791                         ipsec6stat.in_ahreplay++;
 792                         goto fail;
 793                 }
 794         }
 795
 796         /* was it transmitted over the IPsec tunnel SA? */
 797         if (sav->flags & SADB_X_EXT_OLD) {
 798                 /* RFC 1826 */
 799                 stripsiz = sizeof(struct ah) + siz1;
 800         } else {
 801                 /* RFC 2402 */
 802                 stripsiz = sizeof(struct newah) + siz1;
 803         }
 804         if (ipsec6_tunnel_validate(m, off + stripsiz, nxt, sav)) {
 805                 /*
 806                  * strip off all the headers that precedes AH.
 807                  *      IP6 xx AH IP6' payload -> IP6' payload
 808                  *
 809                  * XXX more sanity checks
 810                  * XXX relationship with gif?
 811                  */
 812                 u_int32_t flowinfo;     /* net endian */
 813
 814                 flowinfo = ip6->ip6_flow;
 815                 m_adj(m, off + stripsiz);
 816                 if (m->m_len < sizeof(*ip6)) {
 817                         /*
 818                          * m_pullup is prohibited in KAME IPv6 input processing
 819                          * but there's no other way!
 820                          */
 821                         m = m_pullup(m, sizeof(*ip6));
 822                         if (!m) {
 823                                 ipsec6stat.in_inval++;
 824                                 goto fail;
 825                         }
 826                 }
 827                 ip6 = mtod(m, struct ip6_hdr *);
 828                 /* ECN consideration. */
 829                 ip6_ecn_egress(ip6_ipsec_ecn, &flowinfo, &ip6->ip6_flow);
 830                 if (!key_checktunnelsanity(sav, AF_INET6,
 831                             (caddr_t)&ip6->ip6_src, (caddr_t)&ip6->ip6_dst)) {
 832                         ipseclog((LOG_NOTICE, "ipsec tunnel address mismatch "
 833                             "in IPv6 AH input: %s %s\n",
 834                             ipsec6_logpacketstr(ip6, spi),
 835                             ipsec_logsastr(sav)));
 836                         ipsec6stat.in_inval++;
 837                         goto fail;
 838                 }
 839
 840 #if 1
 841                 /*
 842                  * should the inner packet be considered authentic?
 843                  * see comment in ah4_input().
 844                  */
 845                 m->m_flags &= ~M_AUTHIPHDR;
 846                 m->m_flags &= ~M_AUTHIPDGM;
 847 #endif
 848
 849                 key_sa_recordxfer(sav, m);
 850                 if (ipsec_addhist(m, IPPROTO_AH, spi) != 0 ||
 851                     ipsec_addhist(m, IPPROTO_IPV6, 0) != 0) {
 852                         ipsec6stat.in_nomem++;
 853                         goto fail;
 854                 }
 855
 856                 s = splimp();
 857                 if (IF_QFULL(&ip6intrq)) {
 858                         ipsec6stat.in_inval++;
 859                         splx(s);
 860                         goto fail;
 861                 }
 862                 IF_ENQUEUE(&ip6intrq, m);
 863                 m = NULL;
 864                 schednetisr(NETISR_IPV6); /* can be skipped but to make sure */
 865                 splx(s);
 866                 nxt = IPPROTO_DONE;
 867         } else {
 868                 /*
 869                  * strip off AH.
 870                  */
 871                 char *prvnxtp;
 872
 873                 /*
 874                  * Copy the value of the next header field of AH to the
 875                  * next header field of the previous header.
 876                  * This is necessary because AH will be stripped off below.
 877                  */
 878                 prvnxtp = ip6_get_prevhdr(m, off); /* XXX */
 879                 *prvnxtp = nxt;
 880
 881                 ip6 = mtod(m, struct ip6_hdr *);
 882 #ifndef PULLDOWN_TEST
 883                 /*
 884                  * We do deep-copy since KAME requires that
 885                  * the packet is placed in a single mbuf.
 886                  */
 887                 ovbcopy((caddr_t)ip6, ((caddr_t)ip6) + stripsiz, off);
 888                 m->m_data += stripsiz;
 889                 m->m_len -= stripsiz;
 890                 m->m_pkthdr.len -= stripsiz;
 891 #else
 892                 /*
 893                  * even in m_pulldown case, we need to strip off AH so that
 894                  * we can compute checksum for multiple AH correctly.
 895                  */
 896                 if (m->m_len >= stripsiz + off) {
 897                         ovbcopy((caddr_t)ip6, ((caddr_t)ip6) + stripsiz, off);
 898                         m->m_data += stripsiz;
 899                         m->m_len -= stripsiz;
 900                         m->m_pkthdr.len -= stripsiz;
 901                 } else {
 902                         /*
 903                          * this comes with no copy if the boundary is on
 904                          * cluster
 905                          */
 906                         struct mbuf *n;
 907
 908                         n = m_split(m, off, M_DONTWAIT);
 909                         if (n == NULL) {
 910                                 /* m is retained by m_split */
 911                                 goto fail;
 912                         }
 913                         m_adj(n, stripsiz);
 914                         m_cat(m, n);
 915                         /* m_cat does not update m_pkthdr.len */
 916                         m->m_pkthdr.len += n->m_pkthdr.len;
 917                 }
 918 #endif
 919                 ip6 = mtod(m, struct ip6_hdr *);
 920                 /* XXX jumbogram */
 921                 ip6->ip6_plen = htons(ntohs(ip6->ip6_plen) - stripsiz);
 922
 923                 key_sa_recordxfer(sav, m);
 924                 if (ipsec_addhist(m, IPPROTO_AH, spi) != 0) {
 925                         ipsec6stat.in_nomem++;
 926                         goto fail;
 927                 }
 928         }
 929
 930         *offp = off;
 931         *mp = m;
 932
 933         if (sav) {
 934                 KEYDEBUG(KEYDEBUG_IPSEC_STAMP,
 935                         printf("DP ah6_input call free SA:%p\n", sav));
 936                 key_freesav(sav);
 937         }
 938         ipsec6stat.in_success++;
 939         return nxt;
 940
 941 fail:
 942         if (sav) {
 943                 KEYDEBUG(KEYDEBUG_IPSEC_STAMP,
 944                         printf("DP ah6_input call free SA:%p\n", sav));
 945                 key_freesav(sav);
 946         }
 947         if (m)
 948                 m_freem(m);
 949         return IPPROTO_DONE;
 950 }
 951
 952 void
 953 ah6_ctlinput(cmd, sa, d)
 954         int cmd;
 955         struct sockaddr *sa;
 956         void *d;
 957 {
 958         const struct newah *ahp;
 959         struct newah ah;
 960         struct secasvar *sav;
 961         struct ip6_hdr *ip6;
 962         struct mbuf *m;
 963         struct ip6ctlparam *ip6cp = NULL;
 964         int off;
 965         struct sockaddr_in6 *sa6_src, *sa6_dst;
 966
 967         if (sa->sa_family != AF_INET6 ||
 968             sa->sa_len != sizeof(struct sockaddr_in6))
 969                 return;
 970         if ((unsigned)cmd >= PRC_NCMDS)
 971                 return;
 972
 973         /* if the parameter is from icmp6, decode it. */
 974         if (d != NULL) {
 975                 ip6cp = (struct ip6ctlparam *)d;
 976                 m = ip6cp->ip6c_m;
 977                 ip6 = ip6cp->ip6c_ip6;
 978                 off = ip6cp->ip6c_off;
 979         } else {
 980                 m = NULL;
 981                 ip6 = NULL;
 982                 off = 0; /* fix warning */
 983         }
 984
 985         if (ip6) {
 986                 /*
 987                  * XXX: We assume that when ip6 is non NULL,
 988                  * M and OFF are valid.
 989                  */
 990
 991                 /* check if we can safely examine src and dst ports */
 992                 if (m->m_pkthdr.len < off + sizeof(ah))
 993                         return;
 994
 995                 if (m->m_len < off + sizeof(ah)) {
 996                         /*
 997                          * this should be rare case,
 998                          * so we compromise on this copy...
 999                          */
1000                         m_copydata(m, off, sizeof(ah), (caddr_t)&ah);
1001                         ahp = &ah;
1002                 } else
1003                         ahp = (struct newah *)(mtod(m, caddr_t) + off);
1004
1005                 if (cmd == PRC_MSGSIZE) {
1006                         int valid = 0;
1007
1008                         /*
1009                          * Check to see if we have a valid SA corresponding to
1010                          * the address in the ICMP message payload.
1011                          */
1012                         sa6_src = ip6cp->ip6c_src;
1013                         sa6_dst = (struct sockaddr_in6 *)sa;
1014                         sav = key_allocsa(AF_INET6,
1015                                           (caddr_t)&sa6_src->sin6_addr,
1016                                           (caddr_t)&sa6_dst->sin6_addr,
1017                                           IPPROTO_AH, ahp->ah_spi);
1018                         if (sav) {
1019                                 if (sav->state == SADB_SASTATE_MATURE ||
1020                                     sav->state == SADB_SASTATE_DYING)
1021                                         valid++;
1022                                 key_freesav(sav);
1023                         }
1024
1025                         /* XXX Further validation? */
1026
1027                         /*
1028                          * Depending on the value of "valid" and routing table
1029                          * size (mtudisc_{hi,lo}wat), we will:
1030                          * - recalcurate the new MTU and create the
1031                          *   corresponding routing entry, or
1032                          * - ignore the MTU change notification.
1033                          */
1034                         icmp6_mtudisc_update((struct ip6ctlparam *)d, valid);
1035                 }
1036
1037                 /* we normally notify single pcb here */
1038         } else {
1039                 /* we normally notify any pcb here */
1040         }
1041 }
1042 #endif /* INET6 */