The Design and Implementation of the FreeBSD Operating System, Second Edition
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sys/netinet6/esp_input.c

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    1 /*      $FreeBSD: releng/6.1/sys/netinet6/esp_input.c 158179 2006-04-30 16:44:43Z cvs2svn $     */
    2 /*      $KAME: esp_input.c,v 1.62 2002/01/07 11:39:57 kjc Exp $ */
    3 
    4 /*-
    5  * Copyright (C) 1995, 1996, 1997, and 1998 WIDE Project.
    6  * All rights reserved.
    7  *
    8  * Redistribution and use in source and binary forms, with or without
    9  * modification, are permitted provided that the following conditions
   10  * are met:
   11  * 1. Redistributions of source code must retain the above copyright
   12  *    notice, this list of conditions and the following disclaimer.
   13  * 2. Redistributions in binary form must reproduce the above copyright
   14  *    notice, this list of conditions and the following disclaimer in the
   15  *    documentation and/or other materials provided with the distribution.
   16  * 3. Neither the name of the project nor the names of its contributors
   17  *    may be used to endorse or promote products derived from this software
   18  *    without specific prior written permission.
   19  *
   20  * THIS SOFTWARE IS PROVIDED BY THE PROJECT AND CONTRIBUTORS ``AS IS'' AND
   21  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
   22  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
   23  * ARE DISCLAIMED.  IN NO EVENT SHALL THE PROJECT OR CONTRIBUTORS BE LIABLE
   24  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
   25  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
   26  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
   27  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
   28  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
   29  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
   30  * SUCH DAMAGE.
   31  */
   32 
   33 /*
   34  * RFC1827/2406 Encapsulated Security Payload.
   35  */
   36 
   37 #include "opt_inet.h"
   38 #include "opt_inet6.h"
   39 
   40 #include <sys/param.h>
   41 #include <sys/systm.h>
   42 #include <sys/mbuf.h>
   43 #include <sys/domain.h>
   44 #include <sys/protosw.h>
   45 #include <sys/socket.h>
   46 #include <sys/errno.h>
   47 #include <sys/time.h>
   48 #include <sys/syslog.h>
   49 
   50 #include <net/if.h>
   51 #include <net/route.h>
   52 #include <net/netisr.h>
   53 #include <machine/cpu.h>
   54 
   55 #include <netinet/in.h>
   56 #include <netinet/in_systm.h>
   57 #include <netinet/ip.h>
   58 #include <netinet/ip_var.h>
   59 #include <netinet/in_var.h>
   60 #include <netinet/ip_ecn.h>
   61 #ifdef INET6
   62 #include <netinet6/ip6_ecn.h>
   63 #endif
   64 
   65 #ifdef INET6
   66 #include <netinet/ip6.h>
   67 #include <netinet/in_pcb.h>
   68 #include <netinet6/in6_pcb.h>
   69 #include <netinet6/ip6_var.h>
   70 #include <netinet/icmp6.h>
   71 #include <netinet6/ip6protosw.h>
   72 #endif
   73 
   74 #include <netinet6/ipsec.h>
   75 #ifdef INET6
   76 #include <netinet6/ipsec6.h>
   77 #endif
   78 #include <netinet6/ah.h>
   79 #ifdef INET6
   80 #include <netinet6/ah6.h>
   81 #endif
   82 #include <netinet6/esp.h>
   83 #ifdef INET6
   84 #include <netinet6/esp6.h>
   85 #endif
   86 #include <netkey/key.h>
   87 #include <netkey/keydb.h>
   88 #include <netkey/key_debug.h>
   89 
   90 #include <machine/stdarg.h>
   91 
   92 #include <net/net_osdep.h>
   93 
   94 #define IPLEN_FLIPPED
   95 
   96 #define ESPMAXLEN \
   97         (sizeof(struct esp) < sizeof(struct newesp) \
   98                 ? sizeof(struct newesp) : sizeof(struct esp))
   99 
  100 #ifdef INET
  101 extern struct protosw inetsw[];
  102 
  103 void
  104 esp4_input(m, off)
  105         struct mbuf *m;
  106         int off;
  107 {
  108         struct ip *ip;
  109         struct esp *esp;
  110         struct esptail esptail;
  111         u_int32_t spi;
  112         struct secasvar *sav = NULL;
  113         size_t taillen;
  114         u_int16_t nxt;
  115         const struct esp_algorithm *algo;
  116         int ivlen;
  117         size_t hlen;
  118         size_t esplen;
  119 
  120         /* sanity check for alignment. */
  121         if (off % 4 != 0 || m->m_pkthdr.len % 4 != 0) {
  122                 ipseclog((LOG_ERR, "IPv4 ESP input: packet alignment problem "
  123                         "(off=%d, pktlen=%d)\n", off, m->m_pkthdr.len));
  124                 ipsecstat.in_inval++;
  125                 goto bad;
  126         }
  127 
  128         if (m->m_len < off + ESPMAXLEN) {
  129                 m = m_pullup(m, off + ESPMAXLEN);
  130                 if (!m) {
  131                         ipseclog((LOG_DEBUG,
  132                             "IPv4 ESP input: can't pullup in esp4_input\n"));
  133                         ipsecstat.in_inval++;
  134                         goto bad;
  135                 }
  136         }
  137 
  138         ip = mtod(m, struct ip *);
  139         esp = (struct esp *)(((u_int8_t *)ip) + off);
  140 #ifdef _IP_VHL
  141         hlen = IP_VHL_HL(ip->ip_vhl) << 2;
  142 #else
  143         hlen = ip->ip_hl << 2;
  144 #endif
  145 
  146         /* find the sassoc. */
  147         spi = esp->esp_spi;
  148 
  149         if ((sav = key_allocsa(AF_INET,
  150                               (caddr_t)&ip->ip_src, (caddr_t)&ip->ip_dst,
  151                               IPPROTO_ESP, spi)) == 0) {
  152                 ipseclog((LOG_WARNING,
  153                     "IPv4 ESP input: no key association found for spi %u\n",
  154                     (u_int32_t)ntohl(spi)));
  155                 ipsecstat.in_nosa++;
  156                 goto bad;
  157         }
  158         KEYDEBUG(KEYDEBUG_IPSEC_STAMP,
  159                 printf("DP esp4_input called to allocate SA:%p\n", sav));
  160         if (sav->state != SADB_SASTATE_MATURE
  161          && sav->state != SADB_SASTATE_DYING) {
  162                 ipseclog((LOG_DEBUG,
  163                     "IPv4 ESP input: non-mature/dying SA found for spi %u\n",
  164                     (u_int32_t)ntohl(spi)));
  165                 ipsecstat.in_badspi++;
  166                 goto bad;
  167         }
  168         algo = esp_algorithm_lookup(sav->alg_enc);
  169         if (!algo) {
  170                 ipseclog((LOG_DEBUG, "IPv4 ESP input: "
  171                     "unsupported encryption algorithm for spi %u\n",
  172                     (u_int32_t)ntohl(spi)));
  173                 ipsecstat.in_badspi++;
  174                 goto bad;
  175         }
  176 
  177         /* check if we have proper ivlen information */
  178         ivlen = sav->ivlen;
  179         if (ivlen < 0) {
  180                 ipseclog((LOG_ERR, "inproper ivlen in IPv4 ESP input: %s %s\n",
  181                     ipsec4_logpacketstr(ip, spi), ipsec_logsastr(sav)));
  182                 ipsecstat.in_inval++;
  183                 goto bad;
  184         }
  185 
  186         if (!((sav->flags & SADB_X_EXT_OLD) == 0 && sav->replay
  187          && (sav->alg_auth && sav->key_auth)))
  188                 goto noreplaycheck;
  189 
  190         if (sav->alg_auth == SADB_X_AALG_NULL ||
  191             sav->alg_auth == SADB_AALG_NONE)
  192                 goto noreplaycheck;
  193 
  194         /*
  195          * check for sequence number.
  196          */
  197         if (ipsec_chkreplay(ntohl(((struct newesp *)esp)->esp_seq), sav))
  198                 ; /* okey */
  199         else {
  200                 ipsecstat.in_espreplay++;
  201                 ipseclog((LOG_WARNING,
  202                     "replay packet in IPv4 ESP input: %s %s\n",
  203                     ipsec4_logpacketstr(ip, spi), ipsec_logsastr(sav)));
  204                 goto bad;
  205         }
  206 
  207         /* check ICV */
  208     {
  209         u_int8_t sum0[AH_MAXSUMSIZE];
  210         u_int8_t sum[AH_MAXSUMSIZE];
  211         const struct ah_algorithm *sumalgo;
  212         size_t siz;
  213 
  214         sumalgo = ah_algorithm_lookup(sav->alg_auth);
  215         if (!sumalgo)
  216                 goto noreplaycheck;
  217         siz = (((*sumalgo->sumsiz)(sav) + 3) & ~(4 - 1));
  218         if (m->m_pkthdr.len < off + ESPMAXLEN + siz) {
  219                 ipsecstat.in_inval++;
  220                 goto bad;
  221         }
  222         if (AH_MAXSUMSIZE < siz) {
  223                 ipseclog((LOG_DEBUG,
  224                     "internal error: AH_MAXSUMSIZE must be larger than %lu\n",
  225                     (u_long)siz));
  226                 ipsecstat.in_inval++;
  227                 goto bad;
  228         }
  229 
  230         m_copydata(m, m->m_pkthdr.len - siz, siz, (caddr_t)&sum0[0]);
  231 
  232         if (esp_auth(m, off, m->m_pkthdr.len - off - siz, sav, sum)) {
  233                 ipseclog((LOG_WARNING, "auth fail in IPv4 ESP input: %s %s\n",
  234                     ipsec4_logpacketstr(ip, spi), ipsec_logsastr(sav)));
  235                 ipsecstat.in_espauthfail++;
  236                 goto bad;
  237         }
  238 
  239         if (bcmp(sum0, sum, siz) != 0) {
  240                 ipseclog((LOG_WARNING, "auth fail in IPv4 ESP input: %s %s\n",
  241                     ipsec4_logpacketstr(ip, spi), ipsec_logsastr(sav)));
  242                 ipsecstat.in_espauthfail++;
  243                 goto bad;
  244         }
  245 
  246         /* strip off the authentication data */
  247         m_adj(m, -siz);
  248         ip = mtod(m, struct ip *);
  249 #ifdef IPLEN_FLIPPED
  250         ip->ip_len = ip->ip_len - siz;
  251 #else
  252         ip->ip_len = htons(ntohs(ip->ip_len) - siz);
  253 #endif
  254         m->m_flags |= M_AUTHIPDGM;
  255         ipsecstat.in_espauthsucc++;
  256     }
  257 
  258         /*
  259          * update sequence number.
  260          */
  261         if ((sav->flags & SADB_X_EXT_OLD) == 0 && sav->replay) {
  262                 if (ipsec_updatereplay(ntohl(((struct newesp *)esp)->esp_seq), sav)) {
  263                         ipsecstat.in_espreplay++;
  264                         goto bad;
  265                 }
  266         }
  267 
  268 noreplaycheck:
  269 
  270         /* process main esp header. */
  271         if (sav->flags & SADB_X_EXT_OLD) {
  272                 /* RFC 1827 */
  273                 esplen = sizeof(struct esp);
  274         } else {
  275                 /* RFC 2406 */
  276                 if (sav->flags & SADB_X_EXT_DERIV)
  277                         esplen = sizeof(struct esp);
  278                 else
  279                         esplen = sizeof(struct newesp);
  280         }
  281 
  282         if (m->m_pkthdr.len < off + esplen + ivlen + sizeof(esptail)) {
  283                 ipseclog((LOG_WARNING,
  284                     "IPv4 ESP input: packet too short\n"));
  285                 ipsecstat.in_inval++;
  286                 goto bad;
  287         }
  288 
  289         if (m->m_len < off + esplen + ivlen) {
  290                 m = m_pullup(m, off + esplen + ivlen);
  291                 if (!m) {
  292                         ipseclog((LOG_DEBUG,
  293                             "IPv4 ESP input: can't pullup in esp4_input\n"));
  294                         ipsecstat.in_inval++;
  295                         goto bad;
  296                 }
  297         }
  298 
  299         /*
  300          * pre-compute and cache intermediate key
  301          */
  302         if (esp_schedule(algo, sav) != 0) {
  303                 ipsecstat.in_inval++;
  304                 goto bad;
  305         }
  306 
  307         /*
  308          * decrypt the packet.
  309          */
  310         if (!algo->decrypt)
  311                 panic("internal error: no decrypt function");
  312         if ((*algo->decrypt)(m, off, sav, algo, ivlen)) {
  313                 /* m is already freed */
  314                 m = NULL;
  315                 ipseclog((LOG_ERR, "decrypt fail in IPv4 ESP input: %s\n",
  316                     ipsec_logsastr(sav)));
  317                 ipsecstat.in_inval++;
  318                 goto bad;
  319         }
  320         ipsecstat.in_esphist[sav->alg_enc]++;
  321 
  322         m->m_flags |= M_DECRYPTED;
  323 
  324         /*
  325          * find the trailer of the ESP.
  326          */
  327         m_copydata(m, m->m_pkthdr.len - sizeof(esptail), sizeof(esptail),
  328              (caddr_t)&esptail);
  329         nxt = esptail.esp_nxt;
  330         taillen = esptail.esp_padlen + sizeof(esptail);
  331 
  332         if (m->m_pkthdr.len < taillen ||
  333             m->m_pkthdr.len - taillen < off + esplen + ivlen + sizeof(esptail)) {
  334                 ipseclog((LOG_WARNING,
  335                     "bad pad length in IPv4 ESP input: %s %s\n",
  336                     ipsec4_logpacketstr(ip, spi), ipsec_logsastr(sav)));
  337                 ipsecstat.in_inval++;
  338                 goto bad;
  339         }
  340 
  341         /* strip off the trailing pad area. */
  342         m_adj(m, -taillen);
  343 
  344 #ifdef IPLEN_FLIPPED
  345         ip->ip_len = ip->ip_len - taillen;
  346 #else
  347         ip->ip_len = htons(ntohs(ip->ip_len) - taillen);
  348 #endif
  349 
  350         /* was it transmitted over the IPsec tunnel SA? */
  351         if (ipsec4_tunnel_validate(m, off + esplen + ivlen, nxt, sav)) {
  352                 /*
  353                  * strip off all the headers that precedes ESP header.
  354                  *      IP4 xx ESP IP4' payload -> IP4' payload
  355                  *
  356                  * XXX more sanity checks
  357                  * XXX relationship with gif?
  358                  */
  359                 u_int8_t tos;
  360 
  361                 tos = ip->ip_tos;
  362                 m_adj(m, off + esplen + ivlen);
  363                 if (m->m_len < sizeof(*ip)) {
  364                         m = m_pullup(m, sizeof(*ip));
  365                         if (!m) {
  366                                 ipsecstat.in_inval++;
  367                                 goto bad;
  368                         }
  369                 }
  370                 ip = mtod(m, struct ip *);
  371                 /* ECN consideration. */
  372                 if (!ip_ecn_egress(ip4_ipsec_ecn, &tos, &ip->ip_tos)) {
  373                         ipsecstat.in_inval++;
  374                         goto bad;
  375                 }
  376                 if (!key_checktunnelsanity(sav, AF_INET,
  377                             (caddr_t)&ip->ip_src, (caddr_t)&ip->ip_dst)) {
  378                         ipseclog((LOG_ERR, "ipsec tunnel address mismatch "
  379                             "in IPv4 ESP input: %s %s\n",
  380                             ipsec4_logpacketstr(ip, spi), ipsec_logsastr(sav)));
  381                         ipsecstat.in_inval++;
  382                         goto bad;
  383                 }
  384 
  385                 key_sa_recordxfer(sav, m);
  386                 if (ipsec_addhist(m, IPPROTO_ESP, spi) != 0 ||
  387                     ipsec_addhist(m, IPPROTO_IPV4, 0) != 0) {
  388                         ipsecstat.in_nomem++;
  389                         goto bad;
  390                 }
  391 
  392                 if (netisr_queue(NETISR_IP, m)) {       /* (0) on success. */
  393                         ipsecstat.in_inval++;
  394                         m = NULL;
  395                         goto bad;
  396                 }
  397                 m = NULL;
  398                 nxt = IPPROTO_DONE;
  399         } else {
  400                 /*
  401                  * strip off ESP header and IV.
  402                  * even in m_pulldown case, we need to strip off ESP so that
  403                  * we can always compute checksum for AH correctly.
  404                  */
  405                 size_t stripsiz;
  406 
  407                 stripsiz = esplen + ivlen;
  408 
  409                 ip = mtod(m, struct ip *);
  410                 ovbcopy((caddr_t)ip, (caddr_t)(((u_char *)ip) + stripsiz), off);
  411                 m->m_data += stripsiz;
  412                 m->m_len -= stripsiz;
  413                 m->m_pkthdr.len -= stripsiz;
  414 
  415                 ip = mtod(m, struct ip *);
  416 #ifdef IPLEN_FLIPPED
  417                 ip->ip_len = ip->ip_len - stripsiz;
  418 #else
  419                 ip->ip_len = htons(ntohs(ip->ip_len) - stripsiz);
  420 #endif
  421                 ip->ip_p = nxt;
  422 
  423                 key_sa_recordxfer(sav, m);
  424                 if (ipsec_addhist(m, IPPROTO_ESP, spi) != 0) {
  425                         ipsecstat.in_nomem++;
  426                         goto bad;
  427                 }
  428 
  429                 if (nxt != IPPROTO_DONE) {
  430                         if ((inetsw[ip_protox[nxt]].pr_flags & PR_LASTHDR) != 0 &&
  431                             ipsec4_in_reject(m, NULL)) {
  432                                 ipsecstat.in_polvio++;
  433                                 goto bad;
  434                         }
  435                         (*inetsw[ip_protox[nxt]].pr_input)(m, off);
  436                 } else
  437                         m_freem(m);
  438                 m = NULL;
  439         }
  440 
  441         if (sav) {
  442                 KEYDEBUG(KEYDEBUG_IPSEC_STAMP,
  443                         printf("DP esp4_input call free SA:%p\n", sav));
  444                 key_freesav(sav);
  445         }
  446         ipsecstat.in_success++;
  447         return;
  448 
  449 bad:
  450         if (sav) {
  451                 KEYDEBUG(KEYDEBUG_IPSEC_STAMP,
  452                         printf("DP esp4_input call free SA:%p\n", sav));
  453                 key_freesav(sav);
  454         }
  455         if (m)
  456                 m_freem(m);
  457         return;
  458 }
  459 #endif /* INET */
  460 
  461 #ifdef INET6
  462 int
  463 esp6_input(mp, offp, proto)
  464         struct mbuf **mp;
  465         int *offp, proto;
  466 {
  467         struct mbuf *m = *mp;
  468         int off = *offp;
  469         struct ip6_hdr *ip6;
  470         struct esp *esp;
  471         struct esptail esptail;
  472         u_int32_t spi;
  473         struct secasvar *sav = NULL;
  474         size_t taillen;
  475         u_int16_t nxt;
  476         const struct esp_algorithm *algo;
  477         int ivlen;
  478         size_t esplen;
  479 
  480         /* sanity check for alignment. */
  481         if (off % 4 != 0 || m->m_pkthdr.len % 4 != 0) {
  482                 ipseclog((LOG_ERR, "IPv6 ESP input: packet alignment problem "
  483                         "(off=%d, pktlen=%d)\n", off, m->m_pkthdr.len));
  484                 ipsec6stat.in_inval++;
  485                 goto bad;
  486         }
  487 
  488 #ifndef PULLDOWN_TEST
  489         IP6_EXTHDR_CHECK(m, off, ESPMAXLEN, IPPROTO_DONE);
  490         esp = (struct esp *)(mtod(m, caddr_t) + off);
  491 #else
  492         IP6_EXTHDR_GET(esp, struct esp *, m, off, ESPMAXLEN);
  493         if (esp == NULL) {
  494                 ipsec6stat.in_inval++;
  495                 return IPPROTO_DONE;
  496         }
  497 #endif
  498         ip6 = mtod(m, struct ip6_hdr *);
  499 
  500         if (ntohs(ip6->ip6_plen) == 0) {
  501                 ipseclog((LOG_ERR, "IPv6 ESP input: "
  502                     "ESP with IPv6 jumbogram is not supported.\n"));
  503                 ipsec6stat.in_inval++;
  504                 goto bad;
  505         }
  506 
  507         /* find the sassoc. */
  508         spi = esp->esp_spi;
  509 
  510         if ((sav = key_allocsa(AF_INET6,
  511                               (caddr_t)&ip6->ip6_src, (caddr_t)&ip6->ip6_dst,
  512                               IPPROTO_ESP, spi)) == 0) {
  513                 ipseclog((LOG_WARNING,
  514                     "IPv6 ESP input: no key association found for spi %u\n",
  515                     (u_int32_t)ntohl(spi)));
  516                 ipsec6stat.in_nosa++;
  517                 goto bad;
  518         }
  519         KEYDEBUG(KEYDEBUG_IPSEC_STAMP,
  520                 printf("DP esp6_input called to allocate SA:%p\n", sav));
  521         if (sav->state != SADB_SASTATE_MATURE
  522          && sav->state != SADB_SASTATE_DYING) {
  523                 ipseclog((LOG_DEBUG,
  524                     "IPv6 ESP input: non-mature/dying SA found for spi %u\n",
  525                     (u_int32_t)ntohl(spi)));
  526                 ipsec6stat.in_badspi++;
  527                 goto bad;
  528         }
  529         algo = esp_algorithm_lookup(sav->alg_enc);
  530         if (!algo) {
  531                 ipseclog((LOG_DEBUG, "IPv6 ESP input: "
  532                     "unsupported encryption algorithm for spi %u\n",
  533                     (u_int32_t)ntohl(spi)));
  534                 ipsec6stat.in_badspi++;
  535                 goto bad;
  536         }
  537 
  538         /* check if we have proper ivlen information */
  539         ivlen = sav->ivlen;
  540         if (ivlen < 0) {
  541                 ipseclog((LOG_ERR, "inproper ivlen in IPv6 ESP input: %s %s\n",
  542                     ipsec6_logpacketstr(ip6, spi), ipsec_logsastr(sav)));
  543                 ipsec6stat.in_badspi++;
  544                 goto bad;
  545         }
  546 
  547         if (!((sav->flags & SADB_X_EXT_OLD) == 0 && sav->replay
  548          && (sav->alg_auth && sav->key_auth)))
  549                 goto noreplaycheck;
  550 
  551         if (sav->alg_auth == SADB_X_AALG_NULL ||
  552             sav->alg_auth == SADB_AALG_NONE)
  553                 goto noreplaycheck;
  554 
  555         /*
  556          * check for sequence number.
  557          */
  558         if (ipsec_chkreplay(ntohl(((struct newesp *)esp)->esp_seq), sav))
  559                 ; /* okey */
  560         else {
  561                 ipsec6stat.in_espreplay++;
  562                 ipseclog((LOG_WARNING,
  563                     "replay packet in IPv6 ESP input: %s %s\n",
  564                     ipsec6_logpacketstr(ip6, spi), ipsec_logsastr(sav)));
  565                 goto bad;
  566         }
  567 
  568         /* check ICV */
  569     {
  570         u_char sum0[AH_MAXSUMSIZE];
  571         u_char sum[AH_MAXSUMSIZE];
  572         const struct ah_algorithm *sumalgo;
  573         size_t siz;
  574 
  575         sumalgo = ah_algorithm_lookup(sav->alg_auth);
  576         if (!sumalgo)
  577                 goto noreplaycheck;
  578         siz = (((*sumalgo->sumsiz)(sav) + 3) & ~(4 - 1));
  579         if (m->m_pkthdr.len < off + ESPMAXLEN + siz) {
  580                 ipsec6stat.in_inval++;
  581                 goto bad;
  582         }
  583         if (AH_MAXSUMSIZE < siz) {
  584                 ipseclog((LOG_DEBUG,
  585                     "internal error: AH_MAXSUMSIZE must be larger than %lu\n",
  586                     (u_long)siz));
  587                 ipsec6stat.in_inval++;
  588                 goto bad;
  589         }
  590 
  591         m_copydata(m, m->m_pkthdr.len - siz, siz, (caddr_t)&sum0[0]);
  592 
  593         if (esp_auth(m, off, m->m_pkthdr.len - off - siz, sav, sum)) {
  594                 ipseclog((LOG_WARNING, "auth fail in IPv6 ESP input: %s %s\n",
  595                     ipsec6_logpacketstr(ip6, spi), ipsec_logsastr(sav)));
  596                 ipsec6stat.in_espauthfail++;
  597                 goto bad;
  598         }
  599 
  600         if (bcmp(sum0, sum, siz) != 0) {
  601                 ipseclog((LOG_WARNING, "auth fail in IPv6 ESP input: %s %s\n",
  602                     ipsec6_logpacketstr(ip6, spi), ipsec_logsastr(sav)));
  603                 ipsec6stat.in_espauthfail++;
  604                 goto bad;
  605         }
  606 
  607         /* strip off the authentication data */
  608         m_adj(m, -siz);
  609         ip6 = mtod(m, struct ip6_hdr *);
  610         ip6->ip6_plen = htons(ntohs(ip6->ip6_plen) - siz);
  611 
  612         m->m_flags |= M_AUTHIPDGM;
  613         ipsec6stat.in_espauthsucc++;
  614     }
  615 
  616         /*
  617          * update sequence number.
  618          */
  619         if ((sav->flags & SADB_X_EXT_OLD) == 0 && sav->replay) {
  620                 if (ipsec_updatereplay(ntohl(((struct newesp *)esp)->esp_seq), sav)) {
  621                         ipsec6stat.in_espreplay++;
  622                         goto bad;
  623                 }
  624         }
  625 
  626 noreplaycheck:
  627 
  628         /* process main esp header. */
  629         if (sav->flags & SADB_X_EXT_OLD) {
  630                 /* RFC 1827 */
  631                 esplen = sizeof(struct esp);
  632         } else {
  633                 /* RFC 2406 */
  634                 if (sav->flags & SADB_X_EXT_DERIV)
  635                         esplen = sizeof(struct esp);
  636                 else
  637                         esplen = sizeof(struct newesp);
  638         }
  639 
  640         if (m->m_pkthdr.len < off + esplen + ivlen + sizeof(esptail)) {
  641                 ipseclog((LOG_WARNING,
  642                     "IPv6 ESP input: packet too short\n"));
  643                 ipsec6stat.in_inval++;
  644                 goto bad;
  645         }
  646 
  647 #ifndef PULLDOWN_TEST
  648         IP6_EXTHDR_CHECK(m, off, esplen + ivlen, IPPROTO_DONE); /* XXX */
  649 #else
  650         IP6_EXTHDR_GET(esp, struct esp *, m, off, esplen + ivlen);
  651         if (esp == NULL) {
  652                 ipsec6stat.in_inval++;
  653                 m = NULL;
  654                 goto bad;
  655         }
  656 #endif
  657         ip6 = mtod(m, struct ip6_hdr *);        /* set it again just in case */
  658 
  659         /*
  660          * pre-compute and cache intermediate key
  661          */
  662         if (esp_schedule(algo, sav) != 0) {
  663                 ipsec6stat.in_inval++;
  664                 goto bad;
  665         }
  666 
  667         /*
  668          * decrypt the packet.
  669          */
  670         if (!algo->decrypt)
  671                 panic("internal error: no decrypt function");
  672         if ((*algo->decrypt)(m, off, sav, algo, ivlen)) {
  673                 /* m is already freed */
  674                 m = NULL;
  675                 ipseclog((LOG_ERR, "decrypt fail in IPv6 ESP input: %s\n",
  676                     ipsec_logsastr(sav)));
  677                 ipsec6stat.in_inval++;
  678                 goto bad;
  679         }
  680         ipsec6stat.in_esphist[sav->alg_enc]++;
  681 
  682         m->m_flags |= M_DECRYPTED;
  683 
  684         /*
  685          * find the trailer of the ESP.
  686          */
  687         m_copydata(m, m->m_pkthdr.len - sizeof(esptail), sizeof(esptail),
  688              (caddr_t)&esptail);
  689         nxt = esptail.esp_nxt;
  690         taillen = esptail.esp_padlen + sizeof(esptail);
  691 
  692         if (m->m_pkthdr.len < taillen
  693          || m->m_pkthdr.len - taillen < sizeof(struct ip6_hdr)) {       /* ? */
  694                 ipseclog((LOG_WARNING,
  695                     "bad pad length in IPv6 ESP input: %s %s\n",
  696                     ipsec6_logpacketstr(ip6, spi), ipsec_logsastr(sav)));
  697                 ipsec6stat.in_inval++;
  698                 goto bad;
  699         }
  700 
  701         /* strip off the trailing pad area. */
  702         m_adj(m, -taillen);
  703 
  704         ip6->ip6_plen = htons(ntohs(ip6->ip6_plen) - taillen);
  705 
  706         /* was it transmitted over the IPsec tunnel SA? */
  707         if (ipsec6_tunnel_validate(m, off + esplen + ivlen, nxt, sav)) {
  708                 /*
  709                  * strip off all the headers that precedes ESP header.
  710                  *      IP6 xx ESP IP6' payload -> IP6' payload
  711                  *
  712                  * XXX more sanity checks
  713                  * XXX relationship with gif?
  714                  */
  715                 u_int32_t flowinfo;     /* net endian */
  716                 flowinfo = ip6->ip6_flow;
  717                 m_adj(m, off + esplen + ivlen);
  718                 if (m->m_len < sizeof(*ip6)) {
  719                         m = m_pullup(m, sizeof(*ip6));
  720                         if (!m) {
  721                                 ipsec6stat.in_inval++;
  722                                 goto bad;
  723                         }
  724                 }
  725                 ip6 = mtod(m, struct ip6_hdr *);
  726                 /* ECN consideration. */
  727                 if (!ip6_ecn_egress(ip6_ipsec_ecn, &flowinfo, &ip6->ip6_flow)) {
  728                         ipsec6stat.in_inval++;
  729                         goto bad;
  730                 }
  731                 if (!key_checktunnelsanity(sav, AF_INET6,
  732                             (caddr_t)&ip6->ip6_src, (caddr_t)&ip6->ip6_dst)) {
  733                         ipseclog((LOG_ERR, "ipsec tunnel address mismatch "
  734                             "in IPv6 ESP input: %s %s\n",
  735                             ipsec6_logpacketstr(ip6, spi),
  736                             ipsec_logsastr(sav)));
  737                         ipsec6stat.in_inval++;
  738                         goto bad;
  739                 }
  740 
  741                 key_sa_recordxfer(sav, m);
  742                 if (ipsec_addhist(m, IPPROTO_ESP, spi) != 0 ||
  743                     ipsec_addhist(m, IPPROTO_IPV6, 0) != 0) {
  744                         ipsec6stat.in_nomem++;
  745                         goto bad;
  746                 }
  747 
  748                 if (netisr_queue(NETISR_IPV6, m)) {     /* (0) on success. */
  749                         ipsec6stat.in_inval++;
  750                         m = NULL;
  751                         goto bad;
  752                 }
  753                 m = NULL;
  754                 nxt = IPPROTO_DONE;
  755         } else {
  756                 /*
  757                  * strip off ESP header and IV.
  758                  * even in m_pulldown case, we need to strip off ESP so that
  759                  * we can always compute checksum for AH correctly.
  760                  */
  761                 size_t stripsiz;
  762                 u_int8_t *prvnxtp;
  763 
  764                 /*
  765                  * Set the next header field of the previous header correctly.
  766                  */
  767                 prvnxtp = ip6_get_prevhdr(m, off); /* XXX */
  768                 *prvnxtp = nxt;
  769 
  770                 stripsiz = esplen + ivlen;
  771 
  772                 ip6 = mtod(m, struct ip6_hdr *);
  773                 if (m->m_len >= stripsiz + off) {
  774                         ovbcopy((caddr_t)ip6, ((caddr_t)ip6) + stripsiz, off);
  775                         m->m_data += stripsiz;
  776                         m->m_len -= stripsiz;
  777                         m->m_pkthdr.len -= stripsiz;
  778                 } else {
  779                         /*
  780                          * this comes with no copy if the boundary is on
  781                          * cluster
  782                          */
  783                         struct mbuf *n;
  784 
  785                         n = m_split(m, off, M_DONTWAIT);
  786                         if (n == NULL) {
  787                                 /* m is retained by m_split */
  788                                 goto bad;
  789                         }
  790                         m_adj(n, stripsiz);
  791                         /* m_cat does not update m_pkthdr.len */
  792                         m->m_pkthdr.len += n->m_pkthdr.len;
  793                         m_cat(m, n);
  794                 }
  795 
  796 #ifndef PULLDOWN_TEST
  797                 /*
  798                  * KAME requires that the packet to be contiguous on the
  799                  * mbuf.  We need to make that sure.
  800                  * this kind of code should be avoided.
  801                  * XXX other conditions to avoid running this part?
  802                  */
  803                 if (m->m_len != m->m_pkthdr.len) {
  804                         struct mbuf *n = NULL;
  805                         int maxlen;
  806 
  807                         MGETHDR(n, M_DONTWAIT, MT_HEADER);
  808                         maxlen = MHLEN;
  809                         if (n)
  810                                 M_MOVE_PKTHDR(n, m);
  811                         if (n && n->m_pkthdr.len > maxlen) {
  812                                 MCLGET(n, M_DONTWAIT);
  813                                 maxlen = MCLBYTES;
  814                                 if ((n->m_flags & M_EXT) == 0) {
  815                                         m_free(n);
  816                                         n = NULL;
  817                                 }
  818                         }
  819                         if (!n) {
  820                                 printf("esp6_input: mbuf allocation failed\n");
  821                                 goto bad;
  822                         }
  823 
  824                         if (n->m_pkthdr.len <= maxlen) {
  825                                 m_copydata(m, 0, n->m_pkthdr.len, mtod(n, caddr_t));
  826                                 n->m_len = n->m_pkthdr.len;
  827                                 n->m_next = NULL;
  828                                 m_freem(m);
  829                         } else {
  830                                 m_copydata(m, 0, maxlen, mtod(n, caddr_t));
  831                                 n->m_len = maxlen;
  832                                 n->m_next = m;
  833                                 m_adj(m, maxlen);
  834                         }
  835                         m = n;
  836                 }
  837 #endif
  838 
  839                 ip6 = mtod(m, struct ip6_hdr *);
  840                 ip6->ip6_plen = htons(ntohs(ip6->ip6_plen) - stripsiz);
  841 
  842                 key_sa_recordxfer(sav, m);
  843                 if (ipsec_addhist(m, IPPROTO_ESP, spi) != 0) {
  844                         ipsec6stat.in_nomem++;
  845                         goto bad;
  846                 }
  847         }
  848 
  849         *offp = off;
  850         *mp = m;
  851 
  852         if (sav) {
  853                 KEYDEBUG(KEYDEBUG_IPSEC_STAMP,
  854                         printf("DP esp6_input call free SA:%p\n", sav));
  855                 key_freesav(sav);
  856         }
  857         ipsec6stat.in_success++;
  858         return nxt;
  859 
  860 bad:
  861         if (sav) {
  862                 KEYDEBUG(KEYDEBUG_IPSEC_STAMP,
  863                         printf("DP esp6_input call free SA:%p\n", sav));
  864                 key_freesav(sav);
  865         }
  866         if (m)
  867                 m_freem(m);
  868         return IPPROTO_DONE;
  869 }
  870 
  871 void
  872 esp6_ctlinput(cmd, sa, d)
  873         int cmd;
  874         struct sockaddr *sa;
  875         void *d;
  876 {
  877         const struct newesp *espp;
  878         struct newesp esp;
  879         struct ip6ctlparam *ip6cp = NULL, ip6cp1;
  880         struct secasvar *sav;
  881         struct ip6_hdr *ip6;
  882         struct mbuf *m;
  883         int off;
  884         struct sockaddr_in6 *sa6_src, *sa6_dst;
  885 
  886         if (sa->sa_family != AF_INET6 ||
  887             sa->sa_len != sizeof(struct sockaddr_in6))
  888                 return;
  889         if ((unsigned)cmd >= PRC_NCMDS)
  890                 return;
  891 
  892         /* if the parameter is from icmp6, decode it. */
  893         if (d != NULL) {
  894                 ip6cp = (struct ip6ctlparam *)d;
  895                 m = ip6cp->ip6c_m;
  896                 ip6 = ip6cp->ip6c_ip6;
  897                 off = ip6cp->ip6c_off;
  898         } else {
  899                 m = NULL;
  900                 ip6 = NULL;
  901                 off = 0;        /* calm gcc */
  902         }
  903 
  904         if (ip6) {
  905                 /*
  906                  * Notify the error to all possible sockets via pfctlinput2.
  907                  * Since the upper layer information (such as protocol type,
  908                  * source and destination ports) is embedded in the encrypted
  909                  * data and might have been cut, we can't directly call
  910                  * an upper layer ctlinput function. However, the pcbnotify
  911                  * function will consider source and destination addresses
  912                  * as well as the flow info value, and may be able to find
  913                  * some PCB that should be notified.
  914                  * Although pfctlinput2 will call esp6_ctlinput(), there is
  915                  * no possibility of an infinite loop of function calls,
  916                  * because we don't pass the inner IPv6 header.
  917                  */
  918                 bzero(&ip6cp1, sizeof(ip6cp1));
  919                 ip6cp1.ip6c_src = ip6cp->ip6c_src;
  920                 pfctlinput2(cmd, sa, (void *)&ip6cp1);
  921 
  922                 /*
  923                  * Then go to special cases that need ESP header information.
  924                  * XXX: We assume that when ip6 is non NULL,
  925                  * M and OFF are valid.
  926                  */
  927 
  928                 /* check if we can safely examine src and dst ports */
  929                 if (m->m_pkthdr.len < off + sizeof(esp))
  930                         return;
  931 
  932                 if (m->m_len < off + sizeof(esp)) {
  933                         /*
  934                          * this should be rare case,
  935                          * so we compromise on this copy...
  936                          */
  937                         m_copydata(m, off, sizeof(esp), (caddr_t)&esp);
  938                         espp = &esp;
  939                 } else
  940                         espp = (struct newesp*)(mtod(m, caddr_t) + off);
  941 
  942                 if (cmd == PRC_MSGSIZE) {
  943                         int valid = 0;
  944 
  945                         /*
  946                          * Check to see if we have a valid SA corresponding to
  947                          * the address in the ICMP message payload.
  948                          */
  949                         sa6_src = ip6cp->ip6c_src;
  950                         sa6_dst = (struct sockaddr_in6 *)sa;
  951                         sav = key_allocsa(AF_INET6,
  952                                           (caddr_t)&sa6_src->sin6_addr,
  953                                           (caddr_t)&sa6_dst->sin6_addr,
  954                                           IPPROTO_ESP, espp->esp_spi);
  955                         if (sav) {
  956                                 if (sav->state == SADB_SASTATE_MATURE ||
  957                                     sav->state == SADB_SASTATE_DYING)
  958                                         valid++;
  959                                 key_freesav(sav);
  960                         }
  961 
  962                         /* XXX Further validation? */
  963 
  964                         /*
  965                          * Depending on the value of "valid" and routing table
  966                          * size (mtudisc_{hi,lo}wat), we will:
  967                          * - recalcurate the new MTU and create the
  968                          *   corresponding routing entry, or
  969                          * - ignore the MTU change notification.
  970                          */
  971                         icmp6_mtudisc_update((struct ip6ctlparam *)d, valid);
  972                 }
  973         } else {
  974                 /* we normally notify any pcb here */
  975         }
  976 }
  977 #endif /* INET6 */

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