sys/netproto/ipsec/ipsec_input.c

   1 /*      $FreeBSD: src/sys/netipsec/ipsec_input.c,v 1.2.4.2 2003/03/28 20:32:53 sam Exp $        */
   2 /*      $OpenBSD: ipsec_input.c,v 1.63 2003/02/20 18:35:43 deraadt 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  * This code was written by John Ioannidis for BSD/OS in Athens, Greece,
   9  * 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.
  18  *
  19  * Copyright (C) 1995, 1996, 1997, 1998, 1999 by John Ioannidis,
  20  * Angelos D. Keromytis and Niels Provos.
  21  * Copyright (c) 2001, Angelos D. Keromytis.
  22  *
  23  * Permission to use, copy, and modify this software with or without fee
  24  * is hereby granted, provided that this entire notice is included in
  25  * all copies of any software which is or includes a copy or
  26  * modification of this software.
  27  * You may use this code under the GNU public license if you so wish. Please
  28  * contribute changes back to the authors under this freer than GPL license
  29  * so that we may further the use of strong encryption without limitations to
  30  * all.
  31  *
  32  * THIS SOFTWARE IS BEING PROVIDED "AS IS", WITHOUT ANY EXPRESS OR
  33  * IMPLIED WARRANTY. IN PARTICULAR, NONE OF THE AUTHORS MAKES ANY
  34  * REPRESENTATION OR WARRANTY OF ANY KIND CONCERNING THE
  35  * MERCHANTABILITY OF THIS SOFTWARE OR ITS FITNESS FOR ANY PARTICULAR
  36  * PURPOSE.
  37  */
  38
  39 /*
  40  * IPsec input processing.
  41  */
  42
  43 #include "opt_inet.h"
  44 #include "opt_inet6.h"
  45 #include "opt_ipsec.h"
  46
  47 #include <sys/param.h>
  48 #include <sys/systm.h>
  49 #include <sys/malloc.h>
  50 #include <sys/mbuf.h>
  51 #include <sys/domain.h>
  52 #include <sys/protosw.h>
  53 #include <sys/socket.h>
  54 #include <sys/errno.h>
  55 #include <sys/syslog.h>
  56 #include <sys/in_cksum.h>
  57
  58 #include <net/if.h>
  59 #include <net/route.h>
  60 #include <net/netisr.h>
  61
  62 #include <netinet/in.h>
  63 #include <netinet/in_systm.h>
  64 #include <netinet/ip.h>
  65 #include <netinet/ip_var.h>
  66 #include <netinet/in_var.h>
  67
  68 #include <netinet/ip6.h>
  69 #ifdef INET6
  70 #include <netinet6/ip6_var.h>
  71 #endif
  72 #include <netinet/in_pcb.h>
  73 #ifdef INET6
  74 #include <netinet/icmp6.h>
  75 #endif
  76
  77 #include <netproto/ipsec/ipsec.h>
  78 #ifdef INET6
  79 #include <netproto/ipsec/ipsec6.h>
  80 #endif
  81 #include <netproto/ipsec/ah_var.h>
  82 #include <netproto/ipsec/esp.h>
  83 #include <netproto/ipsec/esp_var.h>
  84 #include <netproto/ipsec/ipcomp_var.h>
  85
  86 #include <netproto/ipsec/key.h>
  87 #include <netproto/ipsec/keydb.h>
  88
  89 #include <netproto/ipsec/xform.h>
  90 #include <netinet6/ip6protosw.h>
  91
  92 #include <machine/stdarg.h>
  93
  94 #include <net/net_osdep.h>
  95
  96 #define IPSEC_ISTAT(p,x,y,z) ((p) == IPPROTO_ESP ? (x)++ : \
  97                             (p) == IPPROTO_AH ? (y)++ : (z)++)
  98
  99 /*
 100  * ipsec_common_input gets called when an IPsec-protected packet
 101  * is received by IPv4 or IPv6.  It's job is to find the right SA
 102  # and call the appropriate transform.  The transform callback
 103  * takes care of further processing (like ingress filtering).
 104  */
 105 static int
 106 ipsec_common_input(struct mbuf *m, int skip, int protoff, int af, int sproto)
 107 {
 108         union sockaddr_union dst_address;
 109         struct secasvar *sav;
 110         u_int32_t spi;
 111         int error;
 112
 113         IPSEC_ISTAT(sproto, espstat.esps_input, ahstat.ahs_input,
 114                 ipcompstat.ipcomps_input);
 115
 116         KASSERT(m != NULL, ("ipsec_common_input: null packet"));
 117
 118         if ((sproto == IPPROTO_ESP && !esp_enable) ||
 119             (sproto == IPPROTO_AH && !ah_enable) ||
 120             (sproto == IPPROTO_IPCOMP && !ipcomp_enable)) {
 121                 m_freem(m);
 122                 IPSEC_ISTAT(sproto, espstat.esps_pdrops, ahstat.ahs_pdrops,
 123                     ipcompstat.ipcomps_pdrops);
 124                 return EOPNOTSUPP;
 125         }
 126
 127         if (m->m_pkthdr.len - skip < 2 * sizeof (u_int32_t)) {
 128                 m_freem(m);
 129                 IPSEC_ISTAT(sproto, espstat.esps_hdrops, ahstat.ahs_hdrops,
 130                     ipcompstat.ipcomps_hdrops);
 131                 DPRINTF(("ipsec_common_input: packet too small\n"));
 132                 return EINVAL;
 133         }
 134
 135         /* Retrieve the SPI from the relevant IPsec header */
 136         if (sproto == IPPROTO_ESP)
 137                 m_copydata(m, skip, sizeof(u_int32_t), (caddr_t) &spi);
 138         else if (sproto == IPPROTO_AH)
 139                 m_copydata(m, skip + sizeof(u_int32_t), sizeof(u_int32_t),
 140                     (caddr_t) &spi);
 141         else if (sproto == IPPROTO_IPCOMP) {
 142                 u_int16_t cpi;
 143                 m_copydata(m, skip + sizeof(u_int16_t), sizeof(u_int16_t),
 144                     (caddr_t) &cpi);
 145                 spi = ntohl(htons(cpi));
 146         }
 147
 148         /*
 149          * Find the SA and (indirectly) call the appropriate
 150          * kernel crypto routine. The resulting mbuf chain is a valid
 151          * IP packet ready to go through input processing.
 152          */
 153         bzero(&dst_address, sizeof (dst_address));
 154         dst_address.sa.sa_family = af;
 155         switch (af) {
 156 #ifdef INET
 157         case AF_INET:
 158                 dst_address.sin.sin_len = sizeof(struct sockaddr_in);
 159                 m_copydata(m, offsetof(struct ip, ip_dst),
 160                     sizeof(struct in_addr),
 161                     (caddr_t) &dst_address.sin.sin_addr);
 162                 break;
 163 #endif /* INET */
 164 #ifdef INET6
 165         case AF_INET6:
 166                 dst_address.sin6.sin6_len = sizeof(struct sockaddr_in6);
 167                 m_copydata(m, offsetof(struct ip6_hdr, ip6_dst),
 168                     sizeof(struct in6_addr),
 169                     (caddr_t) &dst_address.sin6.sin6_addr);
 170                 break;
 171 #endif /* INET6 */
 172         default:
 173                 DPRINTF(("ipsec_common_input: unsupported protocol "
 174                         "family %u\n", af));
 175                 m_freem(m);
 176                 IPSEC_ISTAT(sproto, espstat.esps_nopf, ahstat.ahs_nopf,
 177                     ipcompstat.ipcomps_nopf);
 178                 return EPFNOSUPPORT;
 179         }
 180
 181         crit_enter();
 182
 183         /* NB: only pass dst since key_allocsa follows RFC2401 */
 184         sav = KEY_ALLOCSA(&dst_address, sproto, spi);
 185         if (sav == NULL) {
 186                 DPRINTF(("ipsec_common_input: no key association found for"
 187                           " SA %s/%08lx/%u\n",
 188                           ipsec_address(&dst_address),
 189                           (u_long) ntohl(spi), sproto));
 190                 IPSEC_ISTAT(sproto, espstat.esps_notdb, ahstat.ahs_notdb,
 191                     ipcompstat.ipcomps_notdb);
 192                 crit_exit();
 193                 m_freem(m);
 194                 return ENOENT;
 195         }
 196
 197         if (sav->tdb_xform == NULL) {
 198                 DPRINTF(("ipsec_common_input: attempted to use uninitialized"
 199                          " SA %s/%08lx/%u\n",
 200                          ipsec_address(&dst_address),
 201                          (u_long) ntohl(spi), sproto));
 202                 IPSEC_ISTAT(sproto, espstat.esps_noxform, ahstat.ahs_noxform,
 203                     ipcompstat.ipcomps_noxform);
 204                 KEY_FREESAV(&sav);
 205                 crit_exit();
 206                 m_freem(m);
 207                 return ENXIO;
 208         }
 209
 210         /*
 211          * Call appropriate transform and return -- callback takes care of
 212          * everything else.
 213          */
 214         error = (*sav->tdb_xform->xf_input)(m, sav, skip, protoff);
 215         KEY_FREESAV(&sav);
 216         crit_exit();
 217         return error;
 218 }
 219
 220 #ifdef INET
 221 /*
 222  * Common input handler for IPv4 AH, ESP, and IPCOMP.
 223  */
 224 int
 225 ipsec4_common_input(struct mbuf **m, int *offp, int proto)
 226 {
 227         return ipsec_common_input(*m, *offp, offsetof(struct ip, ip_p),
 228                                   AF_INET, proto);
 229 }
 230
 231 /*
 232  * IPsec input callback for INET protocols.
 233  * This routine is called as the transform callback.
 234  * Takes care of filtering and other sanity checks on
 235  * the processed packet.
 236  */
 237 int
 238 ipsec4_common_input_cb(struct mbuf *m, struct secasvar *sav,
 239                         int skip, int protoff, struct m_tag *mt)
 240 {
 241         int prot, af, sproto;
 242         struct ip *ip;
 243         struct m_tag *mtag;
 244         struct tdb_ident *tdbi;
 245         struct secasindex *saidx;
 246         int error;
 247
 248         KASSERT(m != NULL, ("ipsec4_common_input_cb: null mbuf"));
 249         KASSERT(sav != NULL, ("ipsec4_common_input_cb: null SA"));
 250         KASSERT(sav->sah != NULL, ("ipsec4_common_input_cb: null SAH"));
 251         saidx = &sav->sah->saidx;
 252         af = saidx->dst.sa.sa_family;
 253         KASSERT(af == AF_INET, ("ipsec4_common_input_cb: unexpected af %u",af));
 254         sproto = saidx->proto;
 255         KASSERT(sproto == IPPROTO_ESP || sproto == IPPROTO_AH ||
 256                 sproto == IPPROTO_IPCOMP,
 257                 ("ipsec4_common_input_cb: unexpected security protocol %u",
 258                 sproto));
 259
 260         /* Sanity check */
 261         if (m == NULL) {
 262                 DPRINTF(("ipsec4_common_input_cb: null mbuf"));
 263                 IPSEC_ISTAT(sproto, espstat.esps_badkcr, ahstat.ahs_badkcr,
 264                     ipcompstat.ipcomps_badkcr);
 265                 KEY_FREESAV(&sav);
 266                 return EINVAL;
 267         }
 268
 269         if (skip != 0) {
 270                 /* Fix IPv4 header */
 271                 if (m->m_len < skip && (m = m_pullup(m, skip)) == NULL) {
 272                         DPRINTF(("ipsec4_common_input_cb: processing failed "
 273                             "for SA %s/%08lx\n",
 274                             ipsec_address(&sav->sah->saidx.dst),
 275                             (u_long) ntohl(sav->spi)));
 276                         IPSEC_ISTAT(sproto, espstat.esps_hdrops, ahstat.ahs_hdrops,
 277                             ipcompstat.ipcomps_hdrops);
 278                         error = ENOBUFS;
 279                         goto bad;
 280                 }
 281
 282                 ip = mtod(m, struct ip *);
 283                 ip->ip_len = htons(m->m_pkthdr.len);
 284                 ip->ip_off = htons(ip->ip_off);
 285                 ip->ip_sum = 0;
 286                 ip->ip_sum = in_cksum(m, ip->ip_hl << 2);
 287         } else {
 288                 ip = mtod(m, struct ip *);
 289         }
 290         prot = ip->ip_p;
 291
 292         /* IP-in-IP encapsulation */
 293         if (prot == IPPROTO_IPIP) {
 294                 struct ip ipn;
 295
 296                 if (m->m_pkthdr.len - skip < sizeof(struct ip)) {
 297                         IPSEC_ISTAT(sproto, espstat.esps_hdrops,
 298                             ahstat.ahs_hdrops, ipcompstat.ipcomps_hdrops);
 299                         error = EINVAL;
 300                         goto bad;
 301                 }
 302
 303                 /* ipn will now contain the inner IPv4 header */
 304                 m_copydata(m, skip, sizeof(struct ip), (caddr_t) &ipn);
 305
 306 #ifdef notyet
 307                 /* XXX PROXY address isn't recorded in SAH */
 308                 /*
 309                  * Check that the inner source address is the same as
 310                  * the proxy address, if available.
 311                  */
 312                 if ((saidx->proxy.sa.sa_family == AF_INET &&
 313                     saidx->proxy.sin.sin_addr.s_addr !=
 314                     INADDR_ANY &&
 315                     ipn.ip_src.s_addr !=
 316                     saidx->proxy.sin.sin_addr.s_addr) ||
 317                     (saidx->proxy.sa.sa_family != AF_INET &&
 318                         saidx->proxy.sa.sa_family != 0)) {
 319
 320                         DPRINTF(("ipsec4_common_input_cb: inner "
 321                             "source address %s doesn't correspond to "
 322                             "expected proxy source %s, SA %s/%08lx\n",
 323                             inet_ntoa4(ipn.ip_src),
 324                             ipsp_address(saidx->proxy),
 325                             ipsp_address(saidx->dst),
 326                             (u_long) ntohl(sav->spi)));
 327
 328                         IPSEC_ISTAT(sproto, espstat.esps_pdrops,
 329                             ahstat.ahs_pdrops,
 330                             ipcompstat.ipcomps_pdrops);
 331                         error = EACCES;
 332                         goto bad;
 333                 }
 334 #endif /*XXX*/
 335         }
 336 #if INET6
 337         /* IPv6-in-IP encapsulation. */
 338         if (prot == IPPROTO_IPV6) {
 339                 struct ip6_hdr ip6n;
 340
 341                 if (m->m_pkthdr.len - skip < sizeof(struct ip6_hdr)) {
 342                         IPSEC_ISTAT(sproto, espstat.esps_hdrops,
 343                             ahstat.ahs_hdrops, ipcompstat.ipcomps_hdrops);
 344                         error = EINVAL;
 345                         goto bad;
 346                 }
 347
 348                 /* ip6n will now contain the inner IPv6 header. */
 349                 m_copydata(m, skip, sizeof(struct ip6_hdr), (caddr_t) &ip6n);
 350
 351 #ifdef notyet
 352                 /*
 353                  * Check that the inner source address is the same as
 354                  * the proxy address, if available.
 355                  */
 356                 if ((saidx->proxy.sa.sa_family == AF_INET6 &&
 357                     !IN6_IS_ADDR_UNSPECIFIED(&saidx->proxy.sin6.sin6_addr) &&
 358                     !IN6_ARE_ADDR_EQUAL(&ip6n.ip6_src,
 359                         &saidx->proxy.sin6.sin6_addr)) ||
 360                     (saidx->proxy.sa.sa_family != AF_INET6 &&
 361                         saidx->proxy.sa.sa_family != 0)) {
 362
 363                         DPRINTF(("ipsec4_common_input_cb: inner "
 364                             "source address %s doesn't correspond to "
 365                             "expected proxy source %s, SA %s/%08lx\n",
 366                             ip6_sprintf(&ip6n.ip6_src),
 367                             ipsec_address(&saidx->proxy),
 368                             ipsec_address(&saidx->dst),
 369                             (u_long) ntohl(sav->spi)));
 370
 371                         IPSEC_ISTAT(sproto, espstat.esps_pdrops,
 372                             ahstat.ahs_pdrops,
 373                             ipcompstat.ipcomps_pdrops);
 374                         error = EACCES;
 375                         goto bad;
 376                 }
 377 #endif /*XXX*/
 378         }
 379 #endif /* INET6 */
 380
 381         /*
 382          * Record what we've done to the packet (under what SA it was
 383          * processed). If we've been passed an mtag, it means the packet
 384          * was already processed by an ethernet/crypto combo card and
 385          * thus has a tag attached with all the right information, but
 386          * with a PACKET_TAG_IPSEC_IN_CRYPTO_DONE as opposed to
 387          * PACKET_TAG_IPSEC_IN_DONE type; in that case, just change the type.
 388          */
 389         if (mt == NULL && sproto != IPPROTO_IPCOMP) {
 390                 mtag = m_tag_get(PACKET_TAG_IPSEC_IN_DONE,
 391                                  sizeof(struct tdb_ident), M_NOWAIT);
 392                 if (mtag == NULL) {
 393                         DPRINTF(("ipsec4_common_input_cb: failed to get tag\n"));
 394                         IPSEC_ISTAT(sproto, espstat.esps_hdrops,
 395                             ahstat.ahs_hdrops, ipcompstat.ipcomps_hdrops);
 396                         error = ENOMEM;
 397                         goto bad;
 398                 }
 399
 400                 tdbi = (struct tdb_ident *)m_tag_data(mtag);
 401                 bcopy(&saidx->dst, &tdbi->dst, saidx->dst.sa.sa_len);
 402                 tdbi->proto = sproto;
 403                 tdbi->spi = sav->spi;
 404
 405                 m_tag_prepend(m, mtag);
 406         } else {
 407                 mt->m_tag_id = PACKET_TAG_IPSEC_IN_DONE;
 408                 /* XXX do we need to mark m_flags??? */
 409         }
 410
 411         key_sa_recordxfer(sav, m);              /* record data transfer */
 412
 413         /*
 414          * Re-dispatch via software interrupt.
 415          */
 416         if (netisr_queue(NETISR_IP, m)) {
 417                 IPSEC_ISTAT(sproto, espstat.esps_qfull, ahstat.ahs_qfull,
 418                             ipcompstat.ipcomps_qfull);
 419
 420                 DPRINTF(("ipsec4_common_input_cb: queue full; "
 421                         "proto %u packet dropped\n", sproto));
 422                 return ENOBUFS;
 423         }
 424         return 0;
 425 bad:
 426         m_freem(m);
 427         return error;
 428 }
 429 #endif /* INET */
 430
 431 #ifdef INET6
 432 /* IPv6 AH wrapper. */
 433 int
 434 ipsec6_common_input(struct mbuf **mp, int *offp, int proto)
 435 {
 436         int l = 0;
 437         int protoff;
 438         struct ip6_ext ip6e;
 439
 440         if (*offp < sizeof(struct ip6_hdr)) {
 441                 DPRINTF(("ipsec6_common_input: bad offset %u\n", *offp));
 442                 return IPPROTO_DONE;
 443         } else if (*offp == sizeof(struct ip6_hdr)) {
 444                 protoff = offsetof(struct ip6_hdr, ip6_nxt);
 445         } else {
 446                 /* Chase down the header chain... */
 447                 protoff = sizeof(struct ip6_hdr);
 448
 449                 do {
 450                         protoff += l;
 451                         m_copydata(*mp, protoff, sizeof(ip6e),
 452                             (caddr_t) &ip6e);
 453
 454                         if (ip6e.ip6e_nxt == IPPROTO_AH)
 455                                 l = (ip6e.ip6e_len + 2) << 2;
 456                         else
 457                                 l = (ip6e.ip6e_len + 1) << 3;
 458                         KASSERT(l > 0, ("ah6_input: l went zero or negative"));
 459                 } while (protoff + l < *offp);
 460
 461                 /* Malformed packet check */
 462                 if (protoff + l != *offp) {
 463                         DPRINTF(("ipsec6_common_input: bad packet header chain, "
 464                                 "protoff %u, l %u, off %u\n", protoff, l, *offp));
 465                         IPSEC_ISTAT(proto, espstat.esps_hdrops,
 466                                     ahstat.ahs_hdrops,
 467                                     ipcompstat.ipcomps_hdrops);
 468                         m_freem(*mp);
 469                         *mp = NULL;
 470                         return IPPROTO_DONE;
 471                 }
 472                 protoff += offsetof(struct ip6_ext, ip6e_nxt);
 473         }
 474         ipsec_common_input(*mp, *offp, protoff, AF_INET6, proto);
 475         return IPPROTO_DONE;
 476 }
 477
 478 void
 479 esp6_ctlinput(netmsg_t msg)
 480 {
 481         int cmd = msg->ctlinput.nm_cmd;
 482         struct sockaddr *sa = msg->ctlinput.nm_arg;
 483         void *d = msg->ctlinput.nm_extra;
 484
 485         if (sa->sa_family != AF_INET6 ||
 486             sa->sa_len != sizeof(struct sockaddr_in6))
 487                 return;
 488         if ((unsigned)cmd >= PRC_NCMDS)
 489                 return;
 490
 491         /* if the parameter is from icmp6, decode it. */
 492         if (d !=  NULL) {
 493                 struct ip6ctlparam *ip6cp = (struct ip6ctlparam *)d;
 494                 struct mbuf *m = ip6cp->ip6c_m;
 495                 int off = ip6cp->ip6c_off;
 496
 497                 struct ip6ctlparam ip6cp1;
 498
 499                 /*
 500                  * Notify the error to all possible sockets via kpfctlinput2.
 501                  * Since the upper layer information (such as protocol type,
 502                  * source and destination ports) is embedded in the encrypted
 503                  * data and might have been cut, we can't directly call
 504                  * an upper layer ctlinput function. However, the pcbnotify
 505                  * function will consider source and destination addresses
 506                  * as well as the flow info value, and may be able to find
 507                  * some PCB that should be notified.
 508                  * Although kpfctlinput2 will call esp6_ctlinput(), there is
 509                  * no possibility of an infinite loop of function calls,
 510                  * because we don't pass the inner IPv6 header.
 511                  */
 512                 bzero(&ip6cp1, sizeof(ip6cp1));
 513                 ip6cp1.ip6c_src = ip6cp->ip6c_src;
 514                 kpfctlinput2(cmd, sa, (void *)&ip6cp1);
 515
 516                 /*
 517                  * Then go to special cases that need ESP header information.
 518                  * XXX: We assume that when ip6 is non NULL,
 519                  * M and OFF are valid.
 520                  */
 521
 522                 if (cmd == PRC_MSGSIZE) {
 523                         struct secasvar *sav;
 524                         u_int32_t spi;
 525                         int valid;
 526
 527                         /* check header length before using m_copydata */
 528                         if (m->m_pkthdr.len < off + sizeof (struct esp))
 529                                 return;
 530                         m_copydata(m, off + offsetof(struct esp, esp_spi),
 531                                 sizeof(u_int32_t), (caddr_t) &spi);
 532                         /*
 533                          * Check to see if we have a valid SA corresponding to
 534                          * the address in the ICMP message payload.
 535                          */
 536                         sav = KEY_ALLOCSA((union sockaddr_union *)sa,
 537                                         IPPROTO_ESP, spi);
 538                         valid = (sav != NULL);
 539                         if (sav)
 540                                 KEY_FREESAV(&sav);
 541
 542                         /* XXX Further validation? */
 543
 544                         /*
 545                          * Depending on whether the SA is "valid" and
 546                          * routing table size (mtudisc_{hi,lo}wat), we will:
 547                          * - recalcurate the new MTU and create the
 548                          *   corresponding routing entry, or
 549                          * - ignore the MTU change notification.
 550                          */
 551                         icmp6_mtudisc_update(ip6cp, valid);
 552                 }
 553         } else {
 554                 /* we normally notify any pcb here */
 555         }
 556 }
 557
 558 extern  struct protosw inet6sw[];
 559 extern  u_char ip6_protox[];
 560
 561 /*
 562  * IPsec input callback, called by the transform callback. Takes care of
 563  * filtering and other sanity checks on the processed packet.
 564  */
 565 int
 566 ipsec6_common_input_cb(struct mbuf *m, struct secasvar *sav, int skip, int protoff,
 567     struct m_tag *mt)
 568 {
 569         int prot, af, sproto;
 570         struct ip6_hdr *ip6;
 571         struct m_tag *mtag;
 572         struct tdb_ident *tdbi;
 573         struct secasindex *saidx;
 574         int nxt;
 575         u_int8_t nxt8;
 576         int error, nest;
 577
 578         KASSERT(m != NULL, ("ipsec6_common_input_cb: null mbuf"));
 579         KASSERT(sav != NULL, ("ipsec6_common_input_cb: null SA"));
 580         KASSERT(sav->sah != NULL, ("ipsec6_common_input_cb: null SAH"));
 581         saidx = &sav->sah->saidx;
 582         af = saidx->dst.sa.sa_family;
 583         KASSERT(af == AF_INET6,
 584                 ("ipsec6_common_input_cb: unexpected af %u", af));
 585         sproto = saidx->proto;
 586         KASSERT(sproto == IPPROTO_ESP || sproto == IPPROTO_AH ||
 587                 sproto == IPPROTO_IPCOMP,
 588                 ("ipsec6_common_input_cb: unexpected security protocol %u",
 589                 sproto));
 590
 591         /* Sanity check */
 592         if (m == NULL) {
 593                 DPRINTF(("ipsec4_common_input_cb: null mbuf"));
 594                 IPSEC_ISTAT(sproto, espstat.esps_badkcr, ahstat.ahs_badkcr,
 595                     ipcompstat.ipcomps_badkcr);
 596                 error = EINVAL;
 597                 goto bad;
 598         }
 599
 600         /* Fix IPv6 header */
 601         if (m->m_len < sizeof(struct ip6_hdr) &&
 602             (m = m_pullup(m, sizeof(struct ip6_hdr))) == NULL) {
 603
 604                 DPRINTF(("ipsec_common_input_cb: processing failed "
 605                     "for SA %s/%08lx\n", ipsec_address(&sav->sah->saidx.dst),
 606                     (u_long) ntohl(sav->spi)));
 607
 608                 IPSEC_ISTAT(sproto, espstat.esps_hdrops, ahstat.ahs_hdrops,
 609                     ipcompstat.ipcomps_hdrops);
 610                 error = EACCES;
 611                 goto bad;
 612         }
 613
 614         ip6 = mtod(m, struct ip6_hdr *);
 615         ip6->ip6_plen = htons(m->m_pkthdr.len - sizeof(struct ip6_hdr));
 616
 617         /* Save protocol */
 618         m_copydata(m, protoff, 1, (unsigned char *) &prot);
 619
 620 #ifdef INET
 621         /* IP-in-IP encapsulation */
 622         if (prot == IPPROTO_IPIP) {
 623                 struct ip ipn;
 624
 625                 if (m->m_pkthdr.len - skip < sizeof(struct ip)) {
 626                         IPSEC_ISTAT(sproto, espstat.esps_hdrops,
 627                             ahstat.ahs_hdrops, ipcompstat.ipcomps_hdrops);
 628                         error = EINVAL;
 629                         goto bad;
 630                 }
 631
 632                 /* ipn will now contain the inner IPv4 header */
 633                 m_copydata(m, skip, sizeof(struct ip), (caddr_t) &ipn);
 634
 635 #ifdef notyet
 636                 /*
 637                  * Check that the inner source address is the same as
 638                  * the proxy address, if available.
 639                  */
 640                 if ((saidx->proxy.sa.sa_family == AF_INET &&
 641                     saidx->proxy.sin.sin_addr.s_addr != INADDR_ANY &&
 642                     ipn.ip_src.s_addr != saidx->proxy.sin.sin_addr.s_addr) ||
 643                     (saidx->proxy.sa.sa_family != AF_INET &&
 644                         saidx->proxy.sa.sa_family != 0)) {
 645
 646                         DPRINTF(("ipsec_common_input_cb: inner "
 647                             "source address %s doesn't correspond to "
 648                             "expected proxy source %s, SA %s/%08lx\n",
 649                             inet_ntoa4(ipn.ip_src),
 650                             ipsec_address(&saidx->proxy),
 651                             ipsec_address(&saidx->dst),
 652                             (u_long) ntohl(sav->spi)));
 653
 654                         IPSEC_ISTATsproto, (espstat.esps_pdrops,
 655                             ahstat.ahs_pdrops, ipcompstat.ipcomps_pdrops);
 656                         error = EACCES;
 657                         goto bad;
 658                 }
 659 #endif /*XXX*/
 660         }
 661 #endif /* INET */
 662
 663         /* IPv6-in-IP encapsulation */
 664         if (prot == IPPROTO_IPV6) {
 665                 struct ip6_hdr ip6n;
 666
 667                 if (m->m_pkthdr.len - skip < sizeof(struct ip6_hdr)) {
 668                         IPSEC_ISTAT(sproto, espstat.esps_hdrops,
 669                             ahstat.ahs_hdrops, ipcompstat.ipcomps_hdrops);
 670                         error = EINVAL;
 671                         goto bad;
 672                 }
 673
 674                 /* ip6n will now contain the inner IPv6 header. */
 675                 m_copydata(m, skip, sizeof(struct ip6_hdr), (caddr_t) &ip6n);
 676
 677 #ifdef notyet
 678                 /*
 679                  * Check that the inner source address is the same as
 680                  * the proxy address, if available.
 681                  */
 682                 if ((saidx->proxy.sa.sa_family == AF_INET6 &&
 683                     !IN6_IS_ADDR_UNSPECIFIED(&saidx->proxy.sin6.sin6_addr) &&
 684                     !IN6_ARE_ADDR_EQUAL(&ip6n.ip6_src,
 685                         &saidx->proxy.sin6.sin6_addr)) ||
 686                     (saidx->proxy.sa.sa_family != AF_INET6 &&
 687                         saidx->proxy.sa.sa_family != 0)) {
 688
 689                         DPRINTF(("ipsec_common_input_cb: inner "
 690                             "source address %s doesn't correspond to "
 691                             "expected proxy source %s, SA %s/%08lx\n",
 692                             ip6_sprintf(&ip6n.ip6_src),
 693                             ipsec_address(&saidx->proxy),
 694                             ipsec_address(&saidx->dst),
 695                             (u_long) ntohl(sav->spi)));
 696
 697                         IPSEC_ISTAT(sproto, espstat.esps_pdrops,
 698                             ahstat.ahs_pdrops, ipcompstat.ipcomps_pdrops);
 699                         error = EACCES;
 700                         goto bad;
 701                 }
 702 #endif /*XXX*/
 703         }
 704
 705         /*
 706          * Record what we've done to the packet (under what SA it was
 707          * processed). If we've been passed an mtag, it means the packet
 708          * was already processed by an ethernet/crypto combo card and
 709          * thus has a tag attached with all the right information, but
 710          * with a PACKET_TAG_IPSEC_IN_CRYPTO_DONE as opposed to
 711          * PACKET_TAG_IPSEC_IN_DONE type; in that case, just change the type.
 712          */
 713         if (mt == NULL && sproto != IPPROTO_IPCOMP) {
 714                 mtag = m_tag_get(PACKET_TAG_IPSEC_IN_DONE,
 715                                  sizeof(struct tdb_ident), M_NOWAIT);
 716                 if (mtag == NULL) {
 717                         DPRINTF(("ipsec_common_input_cb: failed to "
 718                             "get tag\n"));
 719                         IPSEC_ISTAT(sproto, espstat.esps_hdrops,
 720                             ahstat.ahs_hdrops, ipcompstat.ipcomps_hdrops);
 721                         error = ENOMEM;
 722                         goto bad;
 723                 }
 724
 725                 tdbi = (struct tdb_ident *)m_tag_data(mtag);
 726                 bcopy(&saidx->dst, &tdbi->dst, sizeof(union sockaddr_union));
 727                 tdbi->proto = sproto;
 728                 tdbi->spi = sav->spi;
 729
 730                 m_tag_prepend(m, mtag);
 731         } else {
 732                 mt->m_tag_id = PACKET_TAG_IPSEC_IN_DONE;
 733                 /* XXX do we need to mark m_flags??? */
 734         }
 735
 736         key_sa_recordxfer(sav, m);
 737
 738         /* Retrieve new protocol */
 739         m_copydata(m, protoff, sizeof(u_int8_t), (caddr_t) &nxt8);
 740
 741         /*
 742          * See the end of ip6_input for this logic.
 743          * IPPROTO_IPV[46] case will be processed just like other ones
 744          */
 745         nest = 0;
 746         nxt = nxt8;
 747         while (nxt != IPPROTO_DONE) {
 748                 if (ip6_hdrnestlimit && (++nest > ip6_hdrnestlimit)) {
 749                         ip6stat.ip6s_toomanyhdr++;
 750                         error = EINVAL;
 751                         goto bad;
 752                 }
 753
 754                 /*
 755                  * Protection against faulty packet - there should be
 756                  * more sanity checks in header chain processing.
 757                  */
 758                 if (m->m_pkthdr.len < skip) {
 759                         ip6stat.ip6s_tooshort++;
 760                         in6_ifstat_inc(m->m_pkthdr.rcvif, ifs6_in_truncated);
 761                         error = EINVAL;
 762                         goto bad;
 763                 }
 764                 /*
 765                  * Enforce IPsec policy checking if we are seeing last header.
 766                  * note that we do not visit this with protocols with pcb layer
 767                  * code - like udp/tcp/raw ip.
 768                  */
 769                 if ((inet6sw[ip6_protox[nxt]].pr_flags & PR_LASTHDR) != 0 &&
 770                     ipsec6_in_reject(m, NULL)) {
 771                         error = EINVAL;
 772                         goto bad;
 773                 }
 774                 nxt = (*inet6sw[ip6_protox[nxt]].pr_input)(&m, &skip, nxt);
 775         }
 776         return 0;
 777 bad:
 778         if (m)
 779                 m_freem(m);
 780         return error;
 781 }
 782 #endif /* INET6 */