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 /*      $DragonFly: src/sys/netproto/ipsec/ipsec_input.c,v 1.13 2008/05/27 01:10:44 dillon Exp $        */
   3 /*      $OpenBSD: ipsec_input.c,v 1.63 2003/02/20 18:35:43 deraadt Exp $        */
   4 /*
   5  * The authors of this code are John Ioannidis (ji@tla.org),
   6  * Angelos D. Keromytis (kermit@csd.uch.gr) and
   7  * Niels Provos (provos@physnet.uni-hamburg.de).
   8  *
   9  * This code was written by John Ioannidis for BSD/OS in Athens, Greece,
  10  * in November 1995.
  11  *
  12  * Ported to OpenBSD and NetBSD, with additional transforms, in December 1996,
  13  * by Angelos D. Keromytis.
  14  *
  15  * Additional transforms and features in 1997 and 1998 by Angelos D. Keromytis
  16  * and Niels Provos.
  17  *
  18  * Additional features in 1999 by Angelos D. Keromytis.
  19  *
  20  * Copyright (C) 1995, 1996, 1997, 1998, 1999 by John Ioannidis,
  21  * Angelos D. Keromytis and Niels Provos.
  22  * Copyright (c) 2001, Angelos D. Keromytis.
  23  *
  24  * Permission to use, copy, and modify this software with or without fee
  25  * is hereby granted, provided that this entire notice is included in
  26  * all copies of any software which is or includes a copy or
  27  * modification of this software.
  28  * You may use this code under the GNU public license if you so wish. Please
  29  * contribute changes back to the authors under this freer than GPL license
  30  * so that we may further the use of strong encryption without limitations to
  31  * all.
  32  *
  33  * THIS SOFTWARE IS BEING PROVIDED "AS IS", WITHOUT ANY EXPRESS OR
  34  * IMPLIED WARRANTY. IN PARTICULAR, NONE OF THE AUTHORS MAKES ANY
  35  * REPRESENTATION OR WARRANTY OF ANY KIND CONCERNING THE
  36  * MERCHANTABILITY OF THIS SOFTWARE OR ITS FITNESS FOR ANY PARTICULAR
  37  * PURPOSE.
  38  */
  39
  40 /*
  41  * IPsec input processing.
  42  */
  43
  44 #include "opt_inet.h"
  45 #include "opt_inet6.h"
  46 #include "opt_ipsec.h"
  47
  48 #include <sys/param.h>
  49 #include <sys/systm.h>
  50 #include <sys/malloc.h>
  51 #include <sys/mbuf.h>
  52 #include <sys/domain.h>
  53 #include <sys/protosw.h>
  54 #include <sys/socket.h>
  55 #include <sys/errno.h>
  56 #include <sys/syslog.h>
  57 #include <sys/in_cksum.h>
  58
  59 #include <net/if.h>
  60 #include <net/route.h>
  61 #include <net/netisr.h>
  62
  63 #include <netinet/in.h>
  64 #include <netinet/in_systm.h>
  65 #include <netinet/ip.h>
  66 #include <netinet/ip_var.h>
  67 #include <netinet/in_var.h>
  68
  69 #include <netinet/ip6.h>
  70 #ifdef INET6
  71 #include <netinet6/ip6_var.h>
  72 #endif
  73 #include <netinet/in_pcb.h>
  74 #ifdef INET6
  75 #include <netinet/icmp6.h>
  76 #endif
  77
  78 #include <netproto/ipsec/ipsec.h>
  79 #ifdef INET6
  80 #include <netproto/ipsec/ipsec6.h>
  81 #endif
  82 #include <netproto/ipsec/ah_var.h>
  83 #include <netproto/ipsec/esp.h>
  84 #include <netproto/ipsec/esp_var.h>
  85 #include <netproto/ipsec/ipcomp_var.h>
  86
  87 #include <netproto/ipsec/key.h>
  88 #include <netproto/ipsec/keydb.h>
  89
  90 #include <netproto/ipsec/xform.h>
  91 #include <netinet6/ip6protosw.h>
  92
  93 #include <machine/stdarg.h>
  94
  95 #include <net/net_osdep.h>
  96
  97 #define IPSEC_ISTAT(p,x,y,z) ((p) == IPPROTO_ESP ? (x)++ : \
  98                             (p) == IPPROTO_AH ? (y)++ : (z)++)
  99
 100 /*
 101  * ipsec_common_input gets called when an IPsec-protected packet
 102  * is received by IPv4 or IPv6.  It's job is to find the right SA
 103  # and call the appropriate transform.  The transform callback
 104  * takes care of further processing (like ingress filtering).
 105  */
 106 static int
 107 ipsec_common_input(struct mbuf *m, int skip, int protoff, int af, int sproto)
 108 {
 109         union sockaddr_union dst_address;
 110         struct secasvar *sav;
 111         u_int32_t spi;
 112         int error;
 113
 114         IPSEC_ISTAT(sproto, espstat.esps_input, ahstat.ahs_input,
 115                 ipcompstat.ipcomps_input);
 116
 117         KASSERT(m != NULL, ("ipsec_common_input: null packet"));
 118
 119         if ((sproto == IPPROTO_ESP && !esp_enable) ||
 120             (sproto == IPPROTO_AH && !ah_enable) ||
 121             (sproto == IPPROTO_IPCOMP && !ipcomp_enable)) {
 122                 m_freem(m);
 123                 IPSEC_ISTAT(sproto, espstat.esps_pdrops, ahstat.ahs_pdrops,
 124                     ipcompstat.ipcomps_pdrops);
 125                 return EOPNOTSUPP;
 126         }
 127
 128         if (m->m_pkthdr.len - skip < 2 * sizeof (u_int32_t)) {
 129                 m_freem(m);
 130                 IPSEC_ISTAT(sproto, espstat.esps_hdrops, ahstat.ahs_hdrops,
 131                     ipcompstat.ipcomps_hdrops);
 132                 DPRINTF(("ipsec_common_input: packet too small\n"));
 133                 return EINVAL;
 134         }
 135
 136         /* Retrieve the SPI from the relevant IPsec header */
 137         if (sproto == IPPROTO_ESP)
 138                 m_copydata(m, skip, sizeof(u_int32_t), (caddr_t) &spi);
 139         else if (sproto == IPPROTO_AH)
 140                 m_copydata(m, skip + sizeof(u_int32_t), sizeof(u_int32_t),
 141                     (caddr_t) &spi);
 142         else if (sproto == IPPROTO_IPCOMP) {
 143                 u_int16_t cpi;
 144                 m_copydata(m, skip + sizeof(u_int16_t), sizeof(u_int16_t),
 145                     (caddr_t) &cpi);
 146                 spi = ntohl(htons(cpi));
 147         }
 148
 149         /*
 150          * Find the SA and (indirectly) call the appropriate
 151          * kernel crypto routine. The resulting mbuf chain is a valid
 152          * IP packet ready to go through input processing.
 153          */
 154         bzero(&dst_address, sizeof (dst_address));
 155         dst_address.sa.sa_family = af;
 156         switch (af) {
 157 #ifdef INET
 158         case AF_INET:
 159                 dst_address.sin.sin_len = sizeof(struct sockaddr_in);
 160                 m_copydata(m, offsetof(struct ip, ip_dst),
 161                     sizeof(struct in_addr),
 162                     (caddr_t) &dst_address.sin.sin_addr);
 163                 break;
 164 #endif /* INET */
 165 #ifdef INET6
 166         case AF_INET6:
 167                 dst_address.sin6.sin6_len = sizeof(struct sockaddr_in6);
 168                 m_copydata(m, offsetof(struct ip6_hdr, ip6_dst),
 169                     sizeof(struct in6_addr),
 170                     (caddr_t) &dst_address.sin6.sin6_addr);
 171                 break;
 172 #endif /* INET6 */
 173         default:
 174                 DPRINTF(("ipsec_common_input: unsupported protocol "
 175                         "family %u\n", af));
 176                 m_freem(m);
 177                 IPSEC_ISTAT(sproto, espstat.esps_nopf, ahstat.ahs_nopf,
 178                     ipcompstat.ipcomps_nopf);
 179                 return EPFNOSUPPORT;
 180         }
 181
 182         crit_enter();
 183
 184         /* NB: only pass dst since key_allocsa follows RFC2401 */
 185         sav = KEY_ALLOCSA(&dst_address, sproto, spi);
 186         if (sav == NULL) {
 187                 DPRINTF(("ipsec_common_input: no key association found for"
 188                           " SA %s/%08lx/%u\n",
 189                           ipsec_address(&dst_address),
 190                           (u_long) ntohl(spi), sproto));
 191                 IPSEC_ISTAT(sproto, espstat.esps_notdb, ahstat.ahs_notdb,
 192                     ipcompstat.ipcomps_notdb);
 193                 crit_exit();
 194                 m_freem(m);
 195                 return ENOENT;
 196         }
 197
 198         if (sav->tdb_xform == NULL) {
 199                 DPRINTF(("ipsec_common_input: attempted to use uninitialized"
 200                          " SA %s/%08lx/%u\n",
 201                          ipsec_address(&dst_address),
 202                          (u_long) ntohl(spi), sproto));
 203                 IPSEC_ISTAT(sproto, espstat.esps_noxform, ahstat.ahs_noxform,
 204                     ipcompstat.ipcomps_noxform);
 205                 KEY_FREESAV(&sav);
 206                 crit_exit();
 207                 m_freem(m);
 208                 return ENXIO;
 209         }
 210
 211         /*
 212          * Call appropriate transform and return -- callback takes care of
 213          * everything else.
 214          */
 215         error = (*sav->tdb_xform->xf_input)(m, sav, skip, protoff);
 216         KEY_FREESAV(&sav);
 217         crit_exit();
 218         return error;
 219 }
 220
 221 #ifdef INET
 222 /*
 223  * Common input handler for IPv4 AH, ESP, and IPCOMP.
 224  */
 225 int
 226 ipsec4_common_input(struct mbuf *m, ...)
 227 {
 228         __va_list ap;
 229         int off, nxt;
 230
 231         __va_start(ap, m);
 232         off = __va_arg(ap, int);
 233         nxt = __va_arg(ap, int);
 234         __va_end(ap);
 235
 236         return ipsec_common_input(m, off, offsetof(struct ip, ip_p),
 237                                   AF_INET, nxt);
 238 }
 239
 240 /*
 241  * IPsec input callback for INET protocols.
 242  * This routine is called as the transform callback.
 243  * Takes care of filtering and other sanity checks on
 244  * the processed packet.
 245  */
 246 int
 247 ipsec4_common_input_cb(struct mbuf *m, struct secasvar *sav,
 248                         int skip, int protoff, struct m_tag *mt)
 249 {
 250         int prot, af, sproto;
 251         struct ip *ip;
 252         struct m_tag *mtag;
 253         struct tdb_ident *tdbi;
 254         struct secasindex *saidx;
 255         int error;
 256
 257         KASSERT(m != NULL, ("ipsec4_common_input_cb: null mbuf"));
 258         KASSERT(sav != NULL, ("ipsec4_common_input_cb: null SA"));
 259         KASSERT(sav->sah != NULL, ("ipsec4_common_input_cb: null SAH"));
 260         saidx = &sav->sah->saidx;
 261         af = saidx->dst.sa.sa_family;
 262         KASSERT(af == AF_INET, ("ipsec4_common_input_cb: unexpected af %u",af));
 263         sproto = saidx->proto;
 264         KASSERT(sproto == IPPROTO_ESP || sproto == IPPROTO_AH ||
 265                 sproto == IPPROTO_IPCOMP,
 266                 ("ipsec4_common_input_cb: unexpected security protocol %u",
 267                 sproto));
 268
 269         /* Sanity check */
 270         if (m == NULL) {
 271                 DPRINTF(("ipsec4_common_input_cb: null mbuf"));
 272                 IPSEC_ISTAT(sproto, espstat.esps_badkcr, ahstat.ahs_badkcr,
 273                     ipcompstat.ipcomps_badkcr);
 274                 KEY_FREESAV(&sav);
 275                 return EINVAL;
 276         }
 277
 278         if (skip != 0) {
 279                 /* Fix IPv4 header */
 280                 if (m->m_len < skip && (m = m_pullup(m, skip)) == NULL) {
 281                         DPRINTF(("ipsec4_common_input_cb: processing failed "
 282                             "for SA %s/%08lx\n",
 283                             ipsec_address(&sav->sah->saidx.dst),
 284                             (u_long) ntohl(sav->spi)));
 285                         IPSEC_ISTAT(sproto, espstat.esps_hdrops, ahstat.ahs_hdrops,
 286                             ipcompstat.ipcomps_hdrops);
 287                         error = ENOBUFS;
 288                         goto bad;
 289                 }
 290
 291                 ip = mtod(m, struct ip *);
 292                 ip->ip_len = htons(m->m_pkthdr.len);
 293                 ip->ip_off = htons(ip->ip_off);
 294                 ip->ip_sum = 0;
 295                 ip->ip_sum = in_cksum(m, ip->ip_hl << 2);
 296         } else {
 297                 ip = mtod(m, struct ip *);
 298         }
 299         prot = ip->ip_p;
 300
 301         /* IP-in-IP encapsulation */
 302         if (prot == IPPROTO_IPIP) {
 303                 struct ip ipn;
 304
 305                 if (m->m_pkthdr.len - skip < sizeof(struct ip)) {
 306                         IPSEC_ISTAT(sproto, espstat.esps_hdrops,
 307                             ahstat.ahs_hdrops, ipcompstat.ipcomps_hdrops);
 308                         error = EINVAL;
 309                         goto bad;
 310                 }
 311
 312                 /* ipn will now contain the inner IPv4 header */
 313                 m_copydata(m, skip, sizeof(struct ip), (caddr_t) &ipn);
 314
 315 #ifdef notyet
 316                 /* XXX PROXY address isn't recorded in SAH */
 317                 /*
 318                  * Check that the inner source address is the same as
 319                  * the proxy address, if available.
 320                  */
 321                 if ((saidx->proxy.sa.sa_family == AF_INET &&
 322                     saidx->proxy.sin.sin_addr.s_addr !=
 323                     INADDR_ANY &&
 324                     ipn.ip_src.s_addr !=
 325                     saidx->proxy.sin.sin_addr.s_addr) ||
 326                     (saidx->proxy.sa.sa_family != AF_INET &&
 327                         saidx->proxy.sa.sa_family != 0)) {
 328
 329                         DPRINTF(("ipsec4_common_input_cb: inner "
 330                             "source address %s doesn't correspond to "
 331                             "expected proxy source %s, SA %s/%08lx\n",
 332                             inet_ntoa4(ipn.ip_src),
 333                             ipsp_address(saidx->proxy),
 334                             ipsp_address(saidx->dst),
 335                             (u_long) ntohl(sav->spi)));
 336
 337                         IPSEC_ISTAT(sproto, espstat.esps_pdrops,
 338                             ahstat.ahs_pdrops,
 339                             ipcompstat.ipcomps_pdrops);
 340                         error = EACCES;
 341                         goto bad;
 342                 }
 343 #endif /*XXX*/
 344         }
 345 #if INET6
 346         /* IPv6-in-IP encapsulation. */
 347         if (prot == IPPROTO_IPV6) {
 348                 struct ip6_hdr ip6n;
 349
 350                 if (m->m_pkthdr.len - skip < sizeof(struct ip6_hdr)) {
 351                         IPSEC_ISTAT(sproto, espstat.esps_hdrops,
 352                             ahstat.ahs_hdrops, ipcompstat.ipcomps_hdrops);
 353                         error = EINVAL;
 354                         goto bad;
 355                 }
 356
 357                 /* ip6n will now contain the inner IPv6 header. */
 358                 m_copydata(m, skip, sizeof(struct ip6_hdr), (caddr_t) &ip6n);
 359
 360 #ifdef notyet
 361                 /*
 362                  * Check that the inner source address is the same as
 363                  * the proxy address, if available.
 364                  */
 365                 if ((saidx->proxy.sa.sa_family == AF_INET6 &&
 366                     !IN6_IS_ADDR_UNSPECIFIED(&saidx->proxy.sin6.sin6_addr) &&
 367                     !IN6_ARE_ADDR_EQUAL(&ip6n.ip6_src,
 368                         &saidx->proxy.sin6.sin6_addr)) ||
 369                     (saidx->proxy.sa.sa_family != AF_INET6 &&
 370                         saidx->proxy.sa.sa_family != 0)) {
 371
 372                         DPRINTF(("ipsec4_common_input_cb: inner "
 373                             "source address %s doesn't correspond to "
 374                             "expected proxy source %s, SA %s/%08lx\n",
 375                             ip6_sprintf(&ip6n.ip6_src),
 376                             ipsec_address(&saidx->proxy),
 377                             ipsec_address(&saidx->dst),
 378                             (u_long) ntohl(sav->spi)));
 379
 380                         IPSEC_ISTAT(sproto, espstat.esps_pdrops,
 381                             ahstat.ahs_pdrops,
 382                             ipcompstat.ipcomps_pdrops);
 383                         error = EACCES;
 384                         goto bad;
 385                 }
 386 #endif /*XXX*/
 387         }
 388 #endif /* INET6 */
 389
 390         /*
 391          * Record what we've done to the packet (under what SA it was
 392          * processed). If we've been passed an mtag, it means the packet
 393          * was already processed by an ethernet/crypto combo card and
 394          * thus has a tag attached with all the right information, but
 395          * with a PACKET_TAG_IPSEC_IN_CRYPTO_DONE as opposed to
 396          * PACKET_TAG_IPSEC_IN_DONE type; in that case, just change the type.
 397          */
 398         if (mt == NULL && sproto != IPPROTO_IPCOMP) {
 399                 mtag = m_tag_get(PACKET_TAG_IPSEC_IN_DONE,
 400                                  sizeof(struct tdb_ident), MB_DONTWAIT);
 401                 if (mtag == NULL) {
 402                         DPRINTF(("ipsec4_common_input_cb: failed to get tag\n"));
 403                         IPSEC_ISTAT(sproto, espstat.esps_hdrops,
 404                             ahstat.ahs_hdrops, ipcompstat.ipcomps_hdrops);
 405                         error = ENOMEM;
 406                         goto bad;
 407                 }
 408
 409                 tdbi = (struct tdb_ident *)m_tag_data(mtag);
 410                 bcopy(&saidx->dst, &tdbi->dst, saidx->dst.sa.sa_len);
 411                 tdbi->proto = sproto;
 412                 tdbi->spi = sav->spi;
 413
 414                 m_tag_prepend(m, mtag);
 415         } else {
 416                 mt->m_tag_id = PACKET_TAG_IPSEC_IN_DONE;
 417                 /* XXX do we need to mark m_flags??? */
 418         }
 419
 420         key_sa_recordxfer(sav, m);              /* record data transfer */
 421
 422         /*
 423          * Re-dispatch via software interrupt.
 424          */
 425         if (netisr_queue(NETISR_IP, m)) {
 426                 IPSEC_ISTAT(sproto, espstat.esps_qfull, ahstat.ahs_qfull,
 427                             ipcompstat.ipcomps_qfull);
 428
 429                 DPRINTF(("ipsec4_common_input_cb: queue full; "
 430                         "proto %u packet dropped\n", sproto));
 431                 return ENOBUFS;
 432         }
 433         return 0;
 434 bad:
 435         m_freem(m);
 436         return error;
 437 }
 438 #endif /* INET */
 439
 440 #ifdef INET6
 441 /* IPv6 AH wrapper. */
 442 int
 443 ipsec6_common_input(struct mbuf **mp, int *offp, int proto)
 444 {
 445         int l = 0;
 446         int protoff;
 447         struct ip6_ext ip6e;
 448
 449         if (*offp < sizeof(struct ip6_hdr)) {
 450                 DPRINTF(("ipsec6_common_input: bad offset %u\n", *offp));
 451                 return IPPROTO_DONE;
 452         } else if (*offp == sizeof(struct ip6_hdr)) {
 453                 protoff = offsetof(struct ip6_hdr, ip6_nxt);
 454         } else {
 455                 /* Chase down the header chain... */
 456                 protoff = sizeof(struct ip6_hdr);
 457
 458                 do {
 459                         protoff += l;
 460                         m_copydata(*mp, protoff, sizeof(ip6e),
 461                             (caddr_t) &ip6e);
 462
 463                         if (ip6e.ip6e_nxt == IPPROTO_AH)
 464                                 l = (ip6e.ip6e_len + 2) << 2;
 465                         else
 466                                 l = (ip6e.ip6e_len + 1) << 3;
 467                         KASSERT(l > 0, ("ah6_input: l went zero or negative"));
 468                 } while (protoff + l < *offp);
 469
 470                 /* Malformed packet check */
 471                 if (protoff + l != *offp) {
 472                         DPRINTF(("ipsec6_common_input: bad packet header chain, "
 473                                 "protoff %u, l %u, off %u\n", protoff, l, *offp));
 474                         IPSEC_ISTAT(proto, espstat.esps_hdrops,
 475                                     ahstat.ahs_hdrops,
 476                                     ipcompstat.ipcomps_hdrops);
 477                         m_freem(*mp);
 478                         *mp = NULL;
 479                         return IPPROTO_DONE;
 480                 }
 481                 protoff += offsetof(struct ip6_ext, ip6e_nxt);
 482         }
 483         ipsec_common_input(*mp, *offp, protoff, AF_INET6, proto);
 484         return IPPROTO_DONE;
 485 }
 486
 487 void
 488 esp6_ctlinput(int cmd, struct sockaddr *sa, void *d)
 489 {
 490         if (sa->sa_family != AF_INET6 ||
 491             sa->sa_len != sizeof(struct sockaddr_in6))
 492                 return;
 493         if ((unsigned)cmd >= PRC_NCMDS)
 494                 return;
 495
 496         /* if the parameter is from icmp6, decode it. */
 497         if (d !=  NULL) {
 498                 struct ip6ctlparam *ip6cp = (struct ip6ctlparam *)d;
 499                 struct mbuf *m = ip6cp->ip6c_m;
 500                 int off = ip6cp->ip6c_off;
 501
 502                 struct ip6ctlparam ip6cp1;
 503
 504                 /*
 505                  * Notify the error to all possible sockets via kpfctlinput2.
 506                  * Since the upper layer information (such as protocol type,
 507                  * source and destination ports) is embedded in the encrypted
 508                  * data and might have been cut, we can't directly call
 509                  * an upper layer ctlinput function. However, the pcbnotify
 510                  * function will consider source and destination addresses
 511                  * as well as the flow info value, and may be able to find
 512                  * some PCB that should be notified.
 513                  * Although kpfctlinput2 will call esp6_ctlinput(), there is
 514                  * no possibility of an infinite loop of function calls,
 515                  * because we don't pass the inner IPv6 header.
 516                  */
 517                 bzero(&ip6cp1, sizeof(ip6cp1));
 518                 ip6cp1.ip6c_src = ip6cp->ip6c_src;
 519                 kpfctlinput2(cmd, sa, (void *)&ip6cp1);
 520
 521                 /*
 522                  * Then go to special cases that need ESP header information.
 523                  * XXX: We assume that when ip6 is non NULL,
 524                  * M and OFF are valid.
 525                  */
 526
 527                 if (cmd == PRC_MSGSIZE) {
 528                         struct secasvar *sav;
 529                         u_int32_t spi;
 530                         int valid;
 531
 532                         /* check header length before using m_copydata */
 533                         if (m->m_pkthdr.len < off + sizeof (struct esp))
 534                                 return;
 535                         m_copydata(m, off + offsetof(struct esp, esp_spi),
 536                                 sizeof(u_int32_t), (caddr_t) &spi);
 537                         /*
 538                          * Check to see if we have a valid SA corresponding to
 539                          * the address in the ICMP message payload.
 540                          */
 541                         sav = KEY_ALLOCSA((union sockaddr_union *)sa,
 542                                         IPPROTO_ESP, spi);
 543                         valid = (sav != NULL);
 544                         if (sav)
 545                                 KEY_FREESAV(&sav);
 546
 547                         /* XXX Further validation? */
 548
 549                         /*
 550                          * Depending on whether the SA is "valid" and
 551                          * routing table size (mtudisc_{hi,lo}wat), we will:
 552                          * - recalcurate the new MTU and create the
 553                          *   corresponding routing entry, or
 554                          * - ignore the MTU change notification.
 555                          */
 556                         icmp6_mtudisc_update(ip6cp, valid);
 557                 }
 558         } else {
 559                 /* we normally notify any pcb here */
 560         }
 561 }
 562
 563 extern  struct ip6protosw inet6sw[];
 564 extern  u_char ip6_protox[];
 565
 566 /*
 567  * IPsec input callback, called by the transform callback. Takes care of
 568  * filtering and other sanity checks on the processed packet.
 569  */
 570 int
 571 ipsec6_common_input_cb(struct mbuf *m, struct secasvar *sav, int skip, int protoff,
 572     struct m_tag *mt)
 573 {
 574         int prot, af, sproto;
 575         struct ip6_hdr *ip6;
 576         struct m_tag *mtag;
 577         struct tdb_ident *tdbi;
 578         struct secasindex *saidx;
 579         int nxt;
 580         u_int8_t nxt8;
 581         int error, nest;
 582
 583         KASSERT(m != NULL, ("ipsec6_common_input_cb: null mbuf"));
 584         KASSERT(sav != NULL, ("ipsec6_common_input_cb: null SA"));
 585         KASSERT(sav->sah != NULL, ("ipsec6_common_input_cb: null SAH"));
 586         saidx = &sav->sah->saidx;
 587         af = saidx->dst.sa.sa_family;
 588         KASSERT(af == AF_INET6,
 589                 ("ipsec6_common_input_cb: unexpected af %u", af));
 590         sproto = saidx->proto;
 591         KASSERT(sproto == IPPROTO_ESP || sproto == IPPROTO_AH ||
 592                 sproto == IPPROTO_IPCOMP,
 593                 ("ipsec6_common_input_cb: unexpected security protocol %u",
 594                 sproto));
 595
 596         /* Sanity check */
 597         if (m == NULL) {
 598                 DPRINTF(("ipsec4_common_input_cb: null mbuf"));
 599                 IPSEC_ISTAT(sproto, espstat.esps_badkcr, ahstat.ahs_badkcr,
 600                     ipcompstat.ipcomps_badkcr);
 601                 error = EINVAL;
 602                 goto bad;
 603         }
 604
 605         /* Fix IPv6 header */
 606         if (m->m_len < sizeof(struct ip6_hdr) &&
 607             (m = m_pullup(m, sizeof(struct ip6_hdr))) == NULL) {
 608
 609                 DPRINTF(("ipsec_common_input_cb: processing failed "
 610                     "for SA %s/%08lx\n", ipsec_address(&sav->sah->saidx.dst),
 611                     (u_long) ntohl(sav->spi)));
 612
 613                 IPSEC_ISTAT(sproto, espstat.esps_hdrops, ahstat.ahs_hdrops,
 614                     ipcompstat.ipcomps_hdrops);
 615                 error = EACCES;
 616                 goto bad;
 617         }
 618
 619         ip6 = mtod(m, struct ip6_hdr *);
 620         ip6->ip6_plen = htons(m->m_pkthdr.len - sizeof(struct ip6_hdr));
 621
 622         /* Save protocol */
 623         m_copydata(m, protoff, 1, (unsigned char *) &prot);
 624
 625 #ifdef INET
 626         /* IP-in-IP encapsulation */
 627         if (prot == IPPROTO_IPIP) {
 628                 struct ip ipn;
 629
 630                 if (m->m_pkthdr.len - skip < sizeof(struct ip)) {
 631                         IPSEC_ISTAT(sproto, espstat.esps_hdrops,
 632                             ahstat.ahs_hdrops, ipcompstat.ipcomps_hdrops);
 633                         error = EINVAL;
 634                         goto bad;
 635                 }
 636
 637                 /* ipn will now contain the inner IPv4 header */
 638                 m_copydata(m, skip, sizeof(struct ip), (caddr_t) &ipn);
 639
 640 #ifdef notyet
 641                 /*
 642                  * Check that the inner source address is the same as
 643                  * the proxy address, if available.
 644                  */
 645                 if ((saidx->proxy.sa.sa_family == AF_INET &&
 646                     saidx->proxy.sin.sin_addr.s_addr != INADDR_ANY &&
 647                     ipn.ip_src.s_addr != saidx->proxy.sin.sin_addr.s_addr) ||
 648                     (saidx->proxy.sa.sa_family != AF_INET &&
 649                         saidx->proxy.sa.sa_family != 0)) {
 650
 651                         DPRINTF(("ipsec_common_input_cb: inner "
 652                             "source address %s doesn't correspond to "
 653                             "expected proxy source %s, SA %s/%08lx\n",
 654                             inet_ntoa4(ipn.ip_src),
 655                             ipsec_address(&saidx->proxy),
 656                             ipsec_address(&saidx->dst),
 657                             (u_long) ntohl(sav->spi)));
 658
 659                         IPSEC_ISTATsproto, (espstat.esps_pdrops,
 660                             ahstat.ahs_pdrops, ipcompstat.ipcomps_pdrops);
 661                         error = EACCES;
 662                         goto bad;
 663                 }
 664 #endif /*XXX*/
 665         }
 666 #endif /* INET */
 667
 668         /* IPv6-in-IP encapsulation */
 669         if (prot == IPPROTO_IPV6) {
 670                 struct ip6_hdr ip6n;
 671
 672                 if (m->m_pkthdr.len - skip < sizeof(struct ip6_hdr)) {
 673                         IPSEC_ISTAT(sproto, espstat.esps_hdrops,
 674                             ahstat.ahs_hdrops, ipcompstat.ipcomps_hdrops);
 675                         error = EINVAL;
 676                         goto bad;
 677                 }
 678
 679                 /* ip6n will now contain the inner IPv6 header. */
 680                 m_copydata(m, skip, sizeof(struct ip6_hdr), (caddr_t) &ip6n);
 681
 682 #ifdef notyet
 683                 /*
 684                  * Check that the inner source address is the same as
 685                  * the proxy address, if available.
 686                  */
 687                 if ((saidx->proxy.sa.sa_family == AF_INET6 &&
 688                     !IN6_IS_ADDR_UNSPECIFIED(&saidx->proxy.sin6.sin6_addr) &&
 689                     !IN6_ARE_ADDR_EQUAL(&ip6n.ip6_src,
 690                         &saidx->proxy.sin6.sin6_addr)) ||
 691                     (saidx->proxy.sa.sa_family != AF_INET6 &&
 692                         saidx->proxy.sa.sa_family != 0)) {
 693
 694                         DPRINTF(("ipsec_common_input_cb: inner "
 695                             "source address %s doesn't correspond to "
 696                             "expected proxy source %s, SA %s/%08lx\n",
 697                             ip6_sprintf(&ip6n.ip6_src),
 698                             ipsec_address(&saidx->proxy),
 699                             ipsec_address(&saidx->dst),
 700                             (u_long) ntohl(sav->spi)));
 701
 702                         IPSEC_ISTAT(sproto, espstat.esps_pdrops,
 703                             ahstat.ahs_pdrops, ipcompstat.ipcomps_pdrops);
 704                         error = EACCES;
 705                         goto bad;
 706                 }
 707 #endif /*XXX*/
 708         }
 709
 710         /*
 711          * Record what we've done to the packet (under what SA it was
 712          * processed). If we've been passed an mtag, it means the packet
 713          * was already processed by an ethernet/crypto combo card and
 714          * thus has a tag attached with all the right information, but
 715          * with a PACKET_TAG_IPSEC_IN_CRYPTO_DONE as opposed to
 716          * PACKET_TAG_IPSEC_IN_DONE type; in that case, just change the type.
 717          */
 718         if (mt == NULL && sproto != IPPROTO_IPCOMP) {
 719                 mtag = m_tag_get(PACKET_TAG_IPSEC_IN_DONE,
 720                                  sizeof(struct tdb_ident), MB_DONTWAIT);
 721                 if (mtag == NULL) {
 722                         DPRINTF(("ipsec_common_input_cb: failed to "
 723                             "get tag\n"));
 724                         IPSEC_ISTAT(sproto, espstat.esps_hdrops,
 725                             ahstat.ahs_hdrops, ipcompstat.ipcomps_hdrops);
 726                         error = ENOMEM;
 727                         goto bad;
 728                 }
 729
 730                 tdbi = (struct tdb_ident *)m_tag_data(mtag);
 731                 bcopy(&saidx->dst, &tdbi->dst, sizeof(union sockaddr_union));
 732                 tdbi->proto = sproto;
 733                 tdbi->spi = sav->spi;
 734
 735                 m_tag_prepend(m, mtag);
 736         } else {
 737                 mt->m_tag_id = PACKET_TAG_IPSEC_IN_DONE;
 738                 /* XXX do we need to mark m_flags??? */
 739         }
 740
 741         key_sa_recordxfer(sav, m);
 742
 743         /* Retrieve new protocol */
 744         m_copydata(m, protoff, sizeof(u_int8_t), (caddr_t) &nxt8);
 745
 746         /*
 747          * See the end of ip6_input for this logic.
 748          * IPPROTO_IPV[46] case will be processed just like other ones
 749          */
 750         nest = 0;
 751         nxt = nxt8;
 752         while (nxt != IPPROTO_DONE) {
 753                 if (ip6_hdrnestlimit && (++nest > ip6_hdrnestlimit)) {
 754                         ip6stat.ip6s_toomanyhdr++;
 755                         error = EINVAL;
 756                         goto bad;
 757                 }
 758
 759                 /*
 760                  * Protection against faulty packet - there should be
 761                  * more sanity checks in header chain processing.
 762                  */
 763                 if (m->m_pkthdr.len < skip) {
 764                         ip6stat.ip6s_tooshort++;
 765                         in6_ifstat_inc(m->m_pkthdr.rcvif, ifs6_in_truncated);
 766                         error = EINVAL;
 767                         goto bad;
 768                 }
 769                 /*
 770                  * Enforce IPsec policy checking if we are seeing last header.
 771                  * note that we do not visit this with protocols with pcb layer
 772                  * code - like udp/tcp/raw ip.
 773                  */
 774                 if ((inet6sw[ip6_protox[nxt]].pr_flags & PR_LASTHDR) != 0 &&
 775                     ipsec6_in_reject(m, NULL)) {
 776                         error = EINVAL;
 777                         goto bad;
 778                 }
 779                 nxt = (*inet6sw[ip6_protox[nxt]].pr_input)(&m, &skip, nxt);
 780         }
 781         return 0;
 782 bad:
 783         if (m)
 784                 m_freem(m);
 785         return error;
 786 }
 787 #endif /* INET6 */