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 1.9 2004/10/20 05:00:36 hsu 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 #include <machine/stdarg.h>
  57
  58 #include <netinet/in.h>
  59 #include <netinet/in_systm.h>
  60 #include <netinet/in_var.h>
  61 #include <netinet/ip.h>
  62 #include <netinet/ip_var.h>
  63 #include <netinet/ip_ecn.h>
  64 #ifdef INET6
  65 #include <netinet6/ip6_ecn.h>
  66 #endif
  67
  68 #ifdef INET6
  69 #include <netinet/ip6.h>
  70 #include <netinet6/ip6_var.h>
  71 #include <netinet6/in6_pcb.h>
  72 #include <netinet/icmp6.h>
  73 #include <netinet6/ip6protosw.h>
  74 #endif
  75
  76 #include <netinet6/ipsec.h>
  77 #ifdef INET6
  78 #include <netinet6/ipsec6.h>
  79 #endif
  80 #include <netinet6/ah.h>
  81 #ifdef INET6
  82 #include <netinet6/ah6.h>
  83 #endif
  84 #include <netproto/key/key.h>
  85 #include <netproto/key/keydb.h>
  86 #ifdef IPSEC_DEBUG
  87 #include <netproto/key/key_debug.h>
  88 #else
  89 #define KEYDEBUG(lev,arg)
  90 #endif
  91
  92 #include <machine/stdarg.h>
  93
  94 #include <net/net_osdep.h>
  95
  96 #define IPLEN_FLIPPED
  97
  98 #ifdef INET
  99 #include <netinet/ipprotosw.h>
 100 extern struct ipprotosw inetsw[];
 101
 102 void
 103 ah4_input(struct mbuf *m, ...)
 104 {
 105         int off, proto;
 106         struct ip *ip;
 107         struct ah *ah;
 108         u_int32_t spi;
 109         const struct ah_algorithm *algo;
 110         size_t siz;
 111         size_t siz1;
 112         u_char *cksum;
 113         struct secasvar *sav = NULL;
 114         u_int16_t nxt;
 115         size_t hlen;
 116         size_t stripsiz = 0;
 117         __va_list ap;
 118
 119         __va_start(ap, m);
 120         off = __va_arg(ap, int);
 121         proto = __va_arg(ap, int);
 122         __va_end(ap);
 123
 124 #ifndef PULLDOWN_TEST
 125         if (m->m_len < off + sizeof(struct newah)) {
 126                 m = m_pullup(m, off + sizeof(struct newah));
 127                 if (!m) {
 128                         ipseclog((LOG_DEBUG, "IPv4 AH input: can't pullup;"
 129                                 "dropping the packet for simplicity\n"));
 130                         ipsecstat.in_inval++;
 131                         goto fail;
 132                 }
 133         }
 134
 135         ip = mtod(m, struct ip *);
 136         ah = (struct ah *)(((caddr_t)ip) + off);
 137 #else
 138         ip = mtod(m, struct ip *);
 139         IP6_EXTHDR_GET(ah, struct ah *, m, off, sizeof(struct newah));
 140         if (ah == NULL) {
 141                 ipseclog((LOG_DEBUG, "IPv4 AH input: can't pullup;"
 142                         "dropping the packet for simplicity\n"));
 143                 ipsecstat.in_inval++;
 144                 goto fail;
 145         }
 146 #endif
 147         nxt = ah->ah_nxt;
 148 #ifdef _IP_VHL
 149         hlen = IP_VHL_HL(ip->ip_vhl) << 2;
 150 #else
 151         hlen = ip->ip_hl << 2;
 152 #endif
 153
 154         /* find the sassoc. */
 155         spi = ah->ah_spi;
 156
 157         if ((sav = key_allocsa(AF_INET,
 158                               (caddr_t)&ip->ip_src, (caddr_t)&ip->ip_dst,
 159                               IPPROTO_AH, spi)) == 0) {
 160                 ipseclog((LOG_WARNING,
 161                     "IPv4 AH input: no key association found for spi %u\n",
 162                     (u_int32_t)ntohl(spi)));
 163                 ipsecstat.in_nosa++;
 164                 goto fail;
 165         }
 166         KEYDEBUG(KEYDEBUG_IPSEC_STAMP,
 167                 printf("DP ah4_input called to allocate SA:%p\n", sav));
 168         if (sav->state != SADB_SASTATE_MATURE
 169          && sav->state != SADB_SASTATE_DYING) {
 170                 ipseclog((LOG_DEBUG,
 171                     "IPv4 AH input: non-mature/dying SA found for spi %u\n",
 172                     (u_int32_t)ntohl(spi)));
 173                 ipsecstat.in_badspi++;
 174                 goto fail;
 175         }
 176
 177         algo = ah_algorithm_lookup(sav->alg_auth);
 178         if (!algo) {
 179                 ipseclog((LOG_DEBUG, "IPv4 AH input: "
 180                     "unsupported authentication algorithm for spi %u\n",
 181                     (u_int32_t)ntohl(spi)));
 182                 ipsecstat.in_badspi++;
 183                 goto fail;
 184         }
 185
 186         siz = (*algo->sumsiz)(sav);
 187         siz1 = ((siz + 3) & ~(4 - 1));
 188
 189         /*
 190          * sanity checks for header, 1.
 191          */
 192     {
 193         int sizoff;
 194
 195         sizoff = (sav->flags & SADB_X_EXT_OLD) ? 0 : 4;
 196
 197         /*
 198          * Here, we do not do "siz1 == siz".  This is because the way
 199          * RFC240[34] section 2 is written.  They do not require truncation
 200          * to 96 bits.
 201          * For example, Microsoft IPsec stack attaches 160 bits of
 202          * authentication data for both hmac-md5 and hmac-sha1.  For hmac-sha1,
 203          * 32 bits of padding is attached.
 204          *
 205          * There are two downsides to this specification.
 206          * They have no real harm, however, they leave us fuzzy feeling.
 207          * - if we attach more than 96 bits of authentication data onto AH,
 208          *   we will never notice about possible modification by rogue
 209          *   intermediate nodes.
 210          *   Since extra bits in AH checksum is never used, this constitutes
 211          *   no real issue, however, it is wacky.
 212          * - even if the peer attaches big authentication data, we will never
 213          *   notice the difference, since longer authentication data will just
 214          *   work.
 215          *
 216          * We may need some clarification in the spec.
 217          */
 218         if (siz1 < siz) {
 219                 ipseclog((LOG_NOTICE, "sum length too short in IPv4 AH input "
 220                     "(%lu, should be at least %lu): %s\n",
 221                     (u_long)siz1, (u_long)siz,
 222                     ipsec4_logpacketstr(ip, spi)));
 223                 ipsecstat.in_inval++;
 224                 goto fail;
 225         }
 226         if ((ah->ah_len << 2) - sizoff != siz1) {
 227                 ipseclog((LOG_NOTICE, "sum length mismatch in IPv4 AH input "
 228                     "(%d should be %lu): %s\n",
 229                     (ah->ah_len << 2) - sizoff, (u_long)siz1,
 230                     ipsec4_logpacketstr(ip, spi)));
 231                 ipsecstat.in_inval++;
 232                 goto fail;
 233         }
 234
 235 #ifndef PULLDOWN_TEST
 236         if (m->m_len < off + sizeof(struct ah) + sizoff + siz1) {
 237                 m = m_pullup(m, off + sizeof(struct ah) + sizoff + siz1);
 238                 if (!m) {
 239                         ipseclog((LOG_DEBUG, "IPv4 AH input: can't pullup\n"));
 240                         ipsecstat.in_inval++;
 241                         goto fail;
 242                 }
 243
 244                 ip = mtod(m, struct ip *);
 245                 ah = (struct ah *)(((caddr_t)ip) + off);
 246         }
 247 #else
 248         IP6_EXTHDR_GET(ah, struct ah *, m, off,
 249                 sizeof(struct ah) + sizoff + siz1);
 250         if (ah == NULL) {
 251                 ipseclog((LOG_DEBUG, "IPv4 AH input: can't pullup\n"));
 252                 ipsecstat.in_inval++;
 253                 goto fail;
 254         }
 255 #endif
 256     }
 257
 258         /*
 259          * check for sequence number.
 260          */
 261         if ((sav->flags & SADB_X_EXT_OLD) == 0 && sav->replay) {
 262                 if (ipsec_chkreplay(ntohl(((struct newah *)ah)->ah_seq), sav))
 263                         ; /* okey */
 264                 else {
 265                         ipsecstat.in_ahreplay++;
 266                         ipseclog((LOG_WARNING,
 267                             "replay packet in IPv4 AH input: %s %s\n",
 268                             ipsec4_logpacketstr(ip, spi), ipsec_logsastr(sav)));
 269                         goto fail;
 270                 }
 271         }
 272
 273         /*
 274          * alright, it seems sane.  now we are going to check the
 275          * cryptographic checksum.
 276          */
 277         cksum = malloc(siz1, M_TEMP, M_NOWAIT);
 278         if (!cksum) {
 279                 ipseclog((LOG_DEBUG, "IPv4 AH input: "
 280                     "couldn't alloc temporary region for cksum\n"));
 281                 ipsecstat.in_inval++;
 282                 goto fail;
 283         }
 284
 285         /*
 286          * some of IP header fields are flipped to the host endian.
 287          * convert them back to network endian.  VERY stupid.
 288          */
 289         ip->ip_len = htons(ip->ip_len + hlen);
 290         ip->ip_off = htons(ip->ip_off);
 291         if (ah4_calccksum(m, (caddr_t)cksum, siz1, algo, sav)) {
 292                 free(cksum, M_TEMP);
 293                 ipsecstat.in_inval++;
 294                 goto fail;
 295         }
 296         ipsecstat.in_ahhist[sav->alg_auth]++;
 297         /*
 298          * flip them back.
 299          */
 300         ip->ip_len = ntohs(ip->ip_len) - hlen;
 301         ip->ip_off = ntohs(ip->ip_off);
 302
 303     {
 304         caddr_t sumpos = NULL;
 305
 306         if (sav->flags & SADB_X_EXT_OLD) {
 307                 /* RFC 1826 */
 308                 sumpos = (caddr_t)(ah + 1);
 309         } else {
 310                 /* RFC 2402 */
 311                 sumpos = (caddr_t)(((struct newah *)ah) + 1);
 312         }
 313
 314         if (bcmp(sumpos, cksum, siz) != 0) {
 315                 ipseclog((LOG_WARNING,
 316                     "checksum mismatch in IPv4 AH input: %s %s\n",
 317                     ipsec4_logpacketstr(ip, spi), ipsec_logsastr(sav)));
 318                 free(cksum, M_TEMP);
 319                 ipsecstat.in_ahauthfail++;
 320                 goto fail;
 321         }
 322     }
 323
 324         free(cksum, M_TEMP);
 325
 326         m->m_flags |= M_AUTHIPHDR;
 327         m->m_flags |= M_AUTHIPDGM;
 328
 329 #if 0
 330         /*
 331          * looks okey, but we need more sanity check.
 332          * XXX should elaborate.
 333          */
 334         if (ah->ah_nxt == IPPROTO_IPIP || ah->ah_nxt == IPPROTO_IP) {
 335                 struct ip *nip;
 336                 size_t sizoff;
 337
 338                 sizoff = (sav->flags & SADB_X_EXT_OLD) ? 0 : 4;
 339
 340                 if (m->m_len < off + sizeof(struct ah) + sizoff + siz1 + hlen) {
 341                         m = m_pullup(m, off + sizeof(struct ah)
 342                                         + sizoff + siz1 + hlen);
 343                         if (!m) {
 344                                 ipseclog((LOG_DEBUG,
 345                                     "IPv4 AH input: can't pullup\n"));
 346                                 ipsecstat.in_inval++;
 347                                 goto fail;
 348                         }
 349                 }
 350
 351                 nip = (struct ip *)((u_char *)(ah + 1) + sizoff + siz1);
 352                 if (nip->ip_src.s_addr != ip->ip_src.s_addr
 353                  || nip->ip_dst.s_addr != ip->ip_dst.s_addr) {
 354                         m->m_flags &= ~M_AUTHIPHDR;
 355                         m->m_flags &= ~M_AUTHIPDGM;
 356                 }
 357         }
 358 #ifdef INET6
 359         else if (ah->ah_nxt == IPPROTO_IPV6) {
 360                 m->m_flags &= ~M_AUTHIPHDR;
 361                 m->m_flags &= ~M_AUTHIPDGM;
 362         }
 363 #endif /* INET6 */
 364 #endif /* 0 */
 365
 366         if (m->m_flags & M_AUTHIPHDR
 367          && m->m_flags & M_AUTHIPDGM) {
 368 #if 0
 369                 ipseclog((LOG_DEBUG,
 370                     "IPv4 AH input: authentication succeess\n"));
 371 #endif
 372                 ipsecstat.in_ahauthsucc++;
 373         } else {
 374                 ipseclog((LOG_WARNING,
 375                     "authentication failed in IPv4 AH input: %s %s\n",
 376                     ipsec4_logpacketstr(ip, spi), ipsec_logsastr(sav)));
 377                 ipsecstat.in_ahauthfail++;
 378                 goto fail;
 379         }
 380
 381         /*
 382          * update sequence number.
 383          */
 384         if ((sav->flags & SADB_X_EXT_OLD) == 0 && sav->replay) {
 385                 if (ipsec_updatereplay(ntohl(((struct newah *)ah)->ah_seq), sav)) {
 386                         ipsecstat.in_ahreplay++;
 387                         goto fail;
 388                 }
 389         }
 390
 391         /* was it transmitted over the IPsec tunnel SA? */
 392         if (sav->flags & SADB_X_EXT_OLD) {
 393                 /* RFC 1826 */
 394                 stripsiz = sizeof(struct ah) + siz1;
 395         } else {
 396                 /* RFC 2402 */
 397                 stripsiz = sizeof(struct newah) + siz1;
 398         }
 399         if (ipsec4_tunnel_validate(m, off + stripsiz, nxt, sav)) {
 400                 /*
 401                  * strip off all the headers that precedes AH.
 402                  *      IP xx AH IP' payload -> IP' payload
 403                  *
 404                  * XXX more sanity checks
 405                  * XXX relationship with gif?
 406                  */
 407                 u_int8_t tos;
 408
 409                 tos = ip->ip_tos;
 410                 m_adj(m, off + stripsiz);
 411                 if (m->m_len < sizeof(*ip)) {
 412                         m = m_pullup(m, sizeof(*ip));
 413                         if (!m) {
 414                                 ipsecstat.in_inval++;
 415                                 goto fail;
 416                         }
 417                 }
 418                 ip = mtod(m, struct ip *);
 419                 /* ECN consideration. */
 420                 ip_ecn_egress(ip4_ipsec_ecn, &tos, &ip->ip_tos);
 421                 if (!key_checktunnelsanity(sav, AF_INET,
 422                             (caddr_t)&ip->ip_src, (caddr_t)&ip->ip_dst)) {
 423                         ipseclog((LOG_NOTICE, "ipsec tunnel address mismatch "
 424                             "in IPv4 AH input: %s %s\n",
 425                             ipsec4_logpacketstr(ip, spi), ipsec_logsastr(sav)));
 426                         ipsecstat.in_inval++;
 427                         goto fail;
 428                 }
 429
 430 #if 1
 431                 /*
 432                  * Should the inner packet be considered authentic?
 433                  * My current answer is: NO.
 434                  *
 435                  * host1 -- gw1 === gw2 -- host2
 436                  *      In this case, gw2 can trust the authenticity of the
 437                  *      outer packet, but NOT inner.  Packet may be altered
 438                  *      between host1 and gw1.
 439                  *
 440                  * host1 -- gw1 === host2
 441                  *      This case falls into the same scenario as above.
 442                  *
 443                  * host1 === host2
 444                  *      This case is the only case when we may be able to leave
 445                  *      M_AUTHIPHDR and M_AUTHIPDGM set.
 446                  *      However, if host1 is wrongly configured, and allows
 447                  *      attacker to inject some packet with src=host1 and
 448                  *      dst=host2, you are in risk.
 449                  */
 450                 m->m_flags &= ~M_AUTHIPHDR;
 451                 m->m_flags &= ~M_AUTHIPDGM;
 452 #endif
 453
 454                 key_sa_recordxfer(sav, m);
 455                 if (ipsec_addhist(m, IPPROTO_AH, spi) != 0 ||
 456                     ipsec_addhist(m, IPPROTO_IPV4, 0) != 0) {
 457                         ipsecstat.in_nomem++;
 458                         goto fail;
 459                 }
 460
 461                 if (netisr_queue(NETISR_IP, m)) {
 462                         ipsecstat.in_inval++;
 463                         m = NULL;
 464                         goto fail;
 465                 }
 466
 467                 nxt = IPPROTO_DONE;
 468         } else {
 469                 /*
 470                  * strip off AH.
 471                  */
 472
 473                 ip = mtod(m, struct ip *);
 474 #ifndef PULLDOWN_TEST
 475                 /*
 476                  * We do deep-copy since KAME requires that
 477                  * the packet is placed in a single external mbuf.
 478                  */
 479                 ovbcopy((caddr_t)ip, (caddr_t)(((u_char *)ip) + stripsiz), off);
 480                 m->m_data += stripsiz;
 481                 m->m_len -= stripsiz;
 482                 m->m_pkthdr.len -= stripsiz;
 483 #else
 484                 /*
 485                  * even in m_pulldown case, we need to strip off AH so that
 486                  * we can compute checksum for multiple AH correctly.
 487                  */
 488                 if (m->m_len >= stripsiz + off) {
 489                         ovbcopy((caddr_t)ip, ((caddr_t)ip) + stripsiz, off);
 490                         m->m_data += stripsiz;
 491                         m->m_len -= stripsiz;
 492                         m->m_pkthdr.len -= stripsiz;
 493                 } else {
 494                         /*
 495                          * this comes with no copy if the boundary is on
 496                          * cluster
 497                          */
 498                         struct mbuf *n;
 499
 500                         n = m_split(m, off, MB_DONTWAIT);
 501                         if (n == NULL) {
 502                                 /* m is retained by m_split */
 503                                 goto fail;
 504                         }
 505                         m_adj(n, stripsiz);
 506                         m_cat(m, n);
 507                         /* m_cat does not update m_pkthdr.len */
 508                         m->m_pkthdr.len += n->m_pkthdr.len;
 509                 }
 510 #endif
 511
 512                 if (m->m_len < sizeof(*ip)) {
 513                         m = m_pullup(m, sizeof(*ip));
 514                         if (m == NULL) {
 515                                 ipsecstat.in_inval++;
 516                                 goto fail;
 517                         }
 518                 }
 519                 ip = mtod(m, struct ip *);
 520 #ifdef IPLEN_FLIPPED
 521                 ip->ip_len = ip->ip_len - stripsiz;
 522 #else
 523                 ip->ip_len = htons(ntohs(ip->ip_len) - stripsiz);
 524 #endif
 525                 ip->ip_p = nxt;
 526                 /* forget about IP hdr checksum, the check has already been passed */
 527
 528                 key_sa_recordxfer(sav, m);
 529                 if (ipsec_addhist(m, IPPROTO_AH, spi) != 0) {
 530                         ipsecstat.in_nomem++;
 531                         goto fail;
 532                 }
 533
 534                 if (nxt != IPPROTO_DONE) {
 535                         if ((inetsw[ip_protox[nxt]].pr_flags & PR_LASTHDR) &&
 536                             ipsec4_in_reject(m, NULL)) {
 537                                 ipsecstat.in_polvio++;
 538                                 goto fail;
 539                         }
 540                         if (!ip_lengthcheck(&m)) {
 541                                 m = NULL;       /* freed in ip_lengthcheck() */
 542                                 goto fail;
 543                         }
 544                         (*inetsw[ip_protox[nxt]].pr_input)(m, off, nxt);
 545                 } else
 546                         m_freem(m);
 547                 m = NULL;
 548         }
 549
 550         if (sav) {
 551                 KEYDEBUG(KEYDEBUG_IPSEC_STAMP,
 552                         printf("DP ah4_input call free SA:%p\n", sav));
 553                 key_freesav(sav);
 554         }
 555         ipsecstat.in_success++;
 556         return;
 557
 558 fail:
 559         if (sav) {
 560                 KEYDEBUG(KEYDEBUG_IPSEC_STAMP,
 561                         printf("DP ah4_input call free SA:%p\n", sav));
 562                 key_freesav(sav);
 563         }
 564         if (m)
 565                 m_freem(m);
 566         return;
 567 }
 568 #endif /* INET */
 569
 570 #ifdef INET6
 571 int
 572 ah6_input(struct mbuf **mp, int *offp, int proto)
 573 {
 574         struct mbuf *m = *mp;
 575         int off = *offp;
 576         struct ip6_hdr *ip6;
 577         struct ah *ah;
 578         u_int32_t spi;
 579         const struct ah_algorithm *algo;
 580         size_t siz;
 581         size_t siz1;
 582         u_char *cksum;
 583         struct secasvar *sav = NULL;
 584         u_int16_t nxt;
 585         size_t stripsiz = 0;
 586
 587 #ifndef PULLDOWN_TEST
 588         IP6_EXTHDR_CHECK(m, off, sizeof(struct ah), IPPROTO_DONE);
 589         ah = (struct ah *)(mtod(m, caddr_t) + off);
 590 #else
 591         IP6_EXTHDR_GET(ah, struct ah *, m, off, sizeof(struct newah));
 592         if (ah == NULL) {
 593                 ipseclog((LOG_DEBUG, "IPv6 AH input: can't pullup\n"));
 594                 ipsec6stat.in_inval++;
 595                 return IPPROTO_DONE;
 596         }
 597 #endif
 598         ip6 = mtod(m, struct ip6_hdr *);
 599         nxt = ah->ah_nxt;
 600
 601         /* find the sassoc. */
 602         spi = ah->ah_spi;
 603
 604         if (ntohs(ip6->ip6_plen) == 0) {
 605                 ipseclog((LOG_ERR, "IPv6 AH input: "
 606                     "AH with IPv6 jumbogram is not supported.\n"));
 607                 ipsec6stat.in_inval++;
 608                 goto fail;
 609         }
 610
 611         if ((sav = key_allocsa(AF_INET6,
 612                               (caddr_t)&ip6->ip6_src, (caddr_t)&ip6->ip6_dst,
 613                               IPPROTO_AH, spi)) == 0) {
 614                 ipseclog((LOG_WARNING,
 615                     "IPv6 AH input: no key association found for spi %u\n",
 616                     (u_int32_t)ntohl(spi)));
 617                 ipsec6stat.in_nosa++;
 618                 goto fail;
 619         }
 620         KEYDEBUG(KEYDEBUG_IPSEC_STAMP,
 621                 printf("DP ah6_input called to allocate SA:%p\n", sav));
 622         if (sav->state != SADB_SASTATE_MATURE
 623          && sav->state != SADB_SASTATE_DYING) {
 624                 ipseclog((LOG_DEBUG,
 625                     "IPv6 AH input: non-mature/dying SA found for spi %u; ",
 626                     (u_int32_t)ntohl(spi)));
 627                 ipsec6stat.in_badspi++;
 628                 goto fail;
 629         }
 630
 631         algo = ah_algorithm_lookup(sav->alg_auth);
 632         if (!algo) {
 633                 ipseclog((LOG_DEBUG, "IPv6 AH input: "
 634                     "unsupported authentication algorithm for spi %u\n",
 635                     (u_int32_t)ntohl(spi)));
 636                 ipsec6stat.in_badspi++;
 637                 goto fail;
 638         }
 639
 640         siz = (*algo->sumsiz)(sav);
 641         siz1 = ((siz + 3) & ~(4 - 1));
 642
 643         /*
 644          * sanity checks for header, 1.
 645          */
 646     {
 647         int sizoff;
 648
 649         sizoff = (sav->flags & SADB_X_EXT_OLD) ? 0 : 4;
 650
 651         /*
 652          * Here, we do not do "siz1 == siz".  See ah4_input() for complete
 653          * description.
 654          */
 655         if (siz1 < siz) {
 656                 ipseclog((LOG_NOTICE, "sum length too short in IPv6 AH input "
 657                     "(%lu, should be at least %lu): %s\n",
 658                     (u_long)siz1, (u_long)siz,
 659                     ipsec6_logpacketstr(ip6, spi)));
 660                 ipsec6stat.in_inval++;
 661                 goto fail;
 662         }
 663         if ((ah->ah_len << 2) - sizoff != siz1) {
 664                 ipseclog((LOG_NOTICE, "sum length mismatch in IPv6 AH input "
 665                     "(%d should be %lu): %s\n",
 666                     (ah->ah_len << 2) - sizoff, (u_long)siz1,
 667                     ipsec6_logpacketstr(ip6, spi)));
 668                 ipsec6stat.in_inval++;
 669                 goto fail;
 670         }
 671 #ifndef PULLDOWN_TEST
 672         IP6_EXTHDR_CHECK(m, off, sizeof(struct ah) + sizoff + siz1, IPPROTO_DONE);
 673 #else
 674         IP6_EXTHDR_GET(ah, struct ah *, m, off,
 675                 sizeof(struct ah) + sizoff + siz1);
 676         if (ah == NULL) {
 677                 ipseclog((LOG_NOTICE, "couldn't pullup gather IPv6 AH checksum part"));
 678                 ipsec6stat.in_inval++;
 679                 m = NULL;
 680                 goto fail;
 681         }
 682 #endif
 683     }
 684
 685         /*
 686          * check for sequence number.
 687          */
 688         if ((sav->flags & SADB_X_EXT_OLD) == 0 && sav->replay) {
 689                 if (ipsec_chkreplay(ntohl(((struct newah *)ah)->ah_seq), sav))
 690                         ; /* okey */
 691                 else {
 692                         ipsec6stat.in_ahreplay++;
 693                         ipseclog((LOG_WARNING,
 694                             "replay packet in IPv6 AH input: %s %s\n",
 695                             ipsec6_logpacketstr(ip6, spi),
 696                             ipsec_logsastr(sav)));
 697                         goto fail;
 698                 }
 699         }
 700
 701         /*
 702          * alright, it seems sane.  now we are going to check the
 703          * cryptographic checksum.
 704          */
 705         cksum = malloc(siz1, M_TEMP, M_NOWAIT);
 706         if (!cksum) {
 707                 ipseclog((LOG_DEBUG, "IPv6 AH input: "
 708                     "couldn't alloc temporary region for cksum\n"));
 709                 ipsec6stat.in_inval++;
 710                 goto fail;
 711         }
 712
 713         if (ah6_calccksum(m, (caddr_t)cksum, siz1, algo, sav)) {
 714                 free(cksum, M_TEMP);
 715                 ipsec6stat.in_inval++;
 716                 goto fail;
 717         }
 718         ipsec6stat.in_ahhist[sav->alg_auth]++;
 719
 720     {
 721         caddr_t sumpos = NULL;
 722
 723         if (sav->flags & SADB_X_EXT_OLD) {
 724                 /* RFC 1826 */
 725                 sumpos = (caddr_t)(ah + 1);
 726         } else {
 727                 /* RFC 2402 */
 728                 sumpos = (caddr_t)(((struct newah *)ah) + 1);
 729         }
 730
 731         if (bcmp(sumpos, cksum, siz) != 0) {
 732                 ipseclog((LOG_WARNING,
 733                     "checksum mismatch in IPv6 AH input: %s %s\n",
 734                     ipsec6_logpacketstr(ip6, spi), ipsec_logsastr(sav)));
 735                 free(cksum, M_TEMP);
 736                 ipsec6stat.in_ahauthfail++;
 737                 goto fail;
 738         }
 739     }
 740
 741         free(cksum, M_TEMP);
 742
 743         m->m_flags |= M_AUTHIPHDR;
 744         m->m_flags |= M_AUTHIPDGM;
 745
 746 #if 0
 747         /*
 748          * looks okey, but we need more sanity check.
 749          * XXX should elaborate.
 750          */
 751         if (ah->ah_nxt == IPPROTO_IPV6) {
 752                 struct ip6_hdr *nip6;
 753                 size_t sizoff;
 754
 755                 sizoff = (sav->flags & SADB_X_EXT_OLD) ? 0 : 4;
 756
 757                 IP6_EXTHDR_CHECK(m, off, sizeof(struct ah) + sizoff + siz1
 758                                 + sizeof(struct ip6_hdr), IPPROTO_DONE);
 759
 760                 nip6 = (struct ip6_hdr *)((u_char *)(ah + 1) + sizoff + siz1);
 761                 if (!IN6_ARE_ADDR_EQUAL(&nip6->ip6_src, &ip6->ip6_src)
 762                  || !IN6_ARE_ADDR_EQUAL(&nip6->ip6_dst, &ip6->ip6_dst)) {
 763                         m->m_flags &= ~M_AUTHIPHDR;
 764                         m->m_flags &= ~M_AUTHIPDGM;
 765                 }
 766         } else if (ah->ah_nxt == IPPROTO_IPIP) {
 767                 m->m_flags &= ~M_AUTHIPHDR;
 768                 m->m_flags &= ~M_AUTHIPDGM;
 769         } else if (ah->ah_nxt == IPPROTO_IP) {
 770                 m->m_flags &= ~M_AUTHIPHDR;
 771                 m->m_flags &= ~M_AUTHIPDGM;
 772         }
 773 #endif
 774
 775         if (m->m_flags & M_AUTHIPHDR
 776          && m->m_flags & M_AUTHIPDGM) {
 777 #if 0
 778                 ipseclog((LOG_DEBUG,
 779                     "IPv6 AH input: authentication succeess\n"));
 780 #endif
 781                 ipsec6stat.in_ahauthsucc++;
 782         } else {
 783                 ipseclog((LOG_WARNING,
 784                     "authentication failed in IPv6 AH input: %s %s\n",
 785                     ipsec6_logpacketstr(ip6, spi), ipsec_logsastr(sav)));
 786                 ipsec6stat.in_ahauthfail++;
 787                 goto fail;
 788         }
 789
 790         /*
 791          * update sequence number.
 792          */
 793         if ((sav->flags & SADB_X_EXT_OLD) == 0 && sav->replay) {
 794                 if (ipsec_updatereplay(ntohl(((struct newah *)ah)->ah_seq), sav)) {
 795                         ipsec6stat.in_ahreplay++;
 796                         goto fail;
 797                 }
 798         }
 799
 800         /* was it transmitted over the IPsec tunnel SA? */
 801         if (sav->flags & SADB_X_EXT_OLD) {
 802                 /* RFC 1826 */
 803                 stripsiz = sizeof(struct ah) + siz1;
 804         } else {
 805                 /* RFC 2402 */
 806                 stripsiz = sizeof(struct newah) + siz1;
 807         }
 808         if (ipsec6_tunnel_validate(m, off + stripsiz, nxt, sav)) {
 809                 /*
 810                  * strip off all the headers that precedes AH.
 811                  *      IP6 xx AH IP6' payload -> IP6' payload
 812                  *
 813                  * XXX more sanity checks
 814                  * XXX relationship with gif?
 815                  */
 816                 u_int32_t flowinfo;     /* net endian */
 817
 818                 flowinfo = ip6->ip6_flow;
 819                 m_adj(m, off + stripsiz);
 820                 if (m->m_len < sizeof(*ip6)) {
 821                         /*
 822                          * m_pullup is prohibited in KAME IPv6 input processing
 823                          * but there's no other way!
 824                          */
 825                         m = m_pullup(m, sizeof(*ip6));
 826                         if (!m) {
 827                                 ipsec6stat.in_inval++;
 828                                 goto fail;
 829                         }
 830                 }
 831                 ip6 = mtod(m, struct ip6_hdr *);
 832                 /* ECN consideration. */
 833                 ip6_ecn_egress(ip6_ipsec_ecn, &flowinfo, &ip6->ip6_flow);
 834                 if (!key_checktunnelsanity(sav, AF_INET6,
 835                             (caddr_t)&ip6->ip6_src, (caddr_t)&ip6->ip6_dst)) {
 836                         ipseclog((LOG_NOTICE, "ipsec tunnel address mismatch "
 837                             "in IPv6 AH input: %s %s\n",
 838                             ipsec6_logpacketstr(ip6, spi),
 839                             ipsec_logsastr(sav)));
 840                         ipsec6stat.in_inval++;
 841                         goto fail;
 842                 }
 843
 844 #if 1
 845                 /*
 846                  * should the inner packet be considered authentic?
 847                  * see comment in ah4_input().
 848                  */
 849                 m->m_flags &= ~M_AUTHIPHDR;
 850                 m->m_flags &= ~M_AUTHIPDGM;
 851 #endif
 852
 853                 key_sa_recordxfer(sav, m);
 854                 if (ipsec_addhist(m, IPPROTO_AH, spi) != 0 ||
 855                     ipsec_addhist(m, IPPROTO_IPV6, 0) != 0) {
 856                         ipsec6stat.in_nomem++;
 857                         goto fail;
 858                 }
 859
 860                 if (netisr_queue(NETISR_IPV6, m)) {
 861                         ipsecstat.in_inval++;
 862                         m = NULL;
 863                         goto fail;
 864                 }
 865
 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, MB_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(int cmd, struct sockaddr *sa, void *d)
 954 {
 955         const struct newah *ahp;
 956         struct newah ah;
 957         struct secasvar *sav;
 958         struct ip6_hdr *ip6;
 959         struct mbuf *m;
 960         struct ip6ctlparam *ip6cp = NULL;
 961         int off;
 962         struct sockaddr_in6 *sa6_src, *sa6_dst;
 963
 964         if (sa->sa_family != AF_INET6 ||
 965             sa->sa_len != sizeof(struct sockaddr_in6))
 966                 return;
 967         if ((unsigned)cmd >= PRC_NCMDS)
 968                 return;
 969
 970         /* if the parameter is from icmp6, decode it. */
 971         if (d != NULL) {
 972                 ip6cp = (struct ip6ctlparam *)d;
 973                 m = ip6cp->ip6c_m;
 974                 ip6 = ip6cp->ip6c_ip6;
 975                 off = ip6cp->ip6c_off;
 976         } else {
 977                 m = NULL;
 978                 ip6 = NULL;
 979                 off = 0; /* fix warning */
 980         }
 981
 982         if (ip6) {
 983                 /*
 984                  * XXX: We assume that when ip6 is non NULL,
 985                  * M and OFF are valid.
 986                  */
 987
 988                 /* check if we can safely examine src and dst ports */
 989                 if (m->m_pkthdr.len < off + sizeof(ah))
 990                         return;
 991
 992                 if (m->m_len < off + sizeof(ah)) {
 993                         /*
 994                          * this should be rare case,
 995                          * so we compromise on this copy...
 996                          */
 997                         m_copydata(m, off, sizeof(ah), (caddr_t)&ah);
 998                         ahp = &ah;
 999                 } else
1000                         ahp = (struct newah *)(mtod(m, caddr_t) + off);
1001
1002                 if (cmd == PRC_MSGSIZE) {
1003                         int valid = 0;
1004
1005                         /*
1006                          * Check to see if we have a valid SA corresponding to
1007                          * the address in the ICMP message payload.
1008                          */
1009                         sa6_src = ip6cp->ip6c_src;
1010                         sa6_dst = (struct sockaddr_in6 *)sa;
1011                         sav = key_allocsa(AF_INET6,
1012                                           (caddr_t)&sa6_src->sin6_addr,
1013                                           (caddr_t)&sa6_dst->sin6_addr,
1014                                           IPPROTO_AH, ahp->ah_spi);
1015                         if (sav) {
1016                                 if (sav->state == SADB_SASTATE_MATURE ||
1017                                     sav->state == SADB_SASTATE_DYING)
1018                                         valid++;
1019                                 key_freesav(sav);
1020                         }
1021
1022                         /* XXX Further validation? */
1023
1024                         /*
1025                          * Depending on the value of "valid" and routing table
1026                          * size (mtudisc_{hi,lo}wat), we will:
1027                          * - recalcurate the new MTU and create the
1028                          *   corresponding routing entry, or
1029                          * - ignore the MTU change notification.
1030                          */
1031                         icmp6_mtudisc_update((struct ip6ctlparam *)d, valid);
1032                 }
1033
1034                 /* we normally notify single pcb here */
1035         } else {
1036                 /* we normally notify any pcb here */
1037         }
1038 }
1039 #endif /* INET6 */