ip6_ipsec.c

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    1 /*-
    2  * Copyright (c) 1982, 1986, 1988, 1993
    3  *      The Regents of the University of California.  All rights reserved.
    4  *
    5  * Redistribution and use in source and binary forms, with or without
    6  * modification, are permitted provided that the following conditions
    7  * are met:
    8  * 1. Redistributions of source code must retain the above copyright
    9  *    notice, this list of conditions and the following disclaimer.
   10  * 2. Redistributions in binary form must reproduce the above copyright
   11  *    notice, this list of conditions and the following disclaimer in the
   12  *    documentation and/or other materials provided with the distribution.
   13  * 4. Neither the name of the University nor the names of its contributors
   14  *    may be used to endorse or promote products derived from this software
   15  *    without specific prior written permission.
   16  *
   17  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
   18  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
   19  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
   20  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
   21  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
   22  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
   23  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
   24  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
   25  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
   26  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
   27  * SUCH DAMAGE.
   28  */
   29 
   30 #include <sys/cdefs.h>
   31 __FBSDID("$FreeBSD: releng/7.4/sys/netinet6/ip6_ipsec.c 214891 2010-11-06 15:56:44Z bz $");
   32 
   33 #include "opt_ipsec.h"
   34 
   35 #include <sys/param.h>
   36 #include <sys/systm.h>
   37 #include <sys/kernel.h>
   38 #include <sys/mac.h>
   39 #include <sys/malloc.h>
   40 #include <sys/mbuf.h>
   41 #include <sys/protosw.h>
   42 #include <sys/socket.h>
   43 #include <sys/socketvar.h>
   44 #include <sys/sysctl.h>
   45 
   46 #include <net/if.h>
   47 #include <net/route.h>
   48 
   49 #include <netinet/in.h>
   50 #include <netinet/in_systm.h>
   51 #include <netinet/in_var.h>
   52 #include <netinet/ip.h>
   53 #include <netinet/in_pcb.h>
   54 #include <netinet/ip_var.h>
   55 #include <netinet/ip_options.h>
   56 
   57 #include <machine/in_cksum.h>
   58 
   59 #ifdef IPSEC
   60 #include <netipsec/ipsec.h>
   61 #include <netipsec/ipsec6.h>
   62 #include <netipsec/xform.h>
   63 #include <netipsec/key.h>
   64 #ifdef IPSEC_DEBUG
   65 #include <netipsec/key_debug.h>
   66 #else
   67 #define KEYDEBUG(lev,arg)
   68 #endif
   69 #endif /*IPSEC*/
   70 
   71 #include <netinet6/ip6_ipsec.h>
   72 #include <netinet6/ip6_var.h>
   73 
   74 extern  struct protosw inet6sw[];
   75 
   76 /*
   77  * Check if we have to jump over firewall processing for this packet.
   78  * Called from ip_input().
   79  * 1 = jump over firewall, 0 = packet goes through firewall.
   80  */
   81 int
   82 ip6_ipsec_filtertunnel(struct mbuf *m)
   83 {
   84 #if defined(IPSEC) && !defined(IPSEC_FILTERTUNNEL)
   85         /*
   86          * Bypass packet filtering for packets from a tunnel.
   87          */
   88         if (m_tag_find(m, PACKET_TAG_IPSEC_IN_DONE, NULL) != NULL)
   89                 return 1;
   90 #endif
   91         return 0;
   92 }
   93 
   94 /*
   95  * Check if this packet has an active SA and needs to be dropped instead
   96  * of forwarded.
   97  * Called from ip_input().
   98  * 1 = drop packet, 0 = forward packet.
   99  */
  100 int
  101 ip6_ipsec_fwd(struct mbuf *m)
  102 {
  103 #ifdef IPSEC
  104         struct m_tag *mtag;
  105         struct tdb_ident *tdbi;
  106         struct secpolicy *sp;
  107         int s, error;
  108         mtag = m_tag_find(m, PACKET_TAG_IPSEC_IN_DONE, NULL);
  109         s = splnet();
  110         if (mtag != NULL) {
  111                 tdbi = (struct tdb_ident *)(mtag + 1);
  112                 sp = ipsec_getpolicy(tdbi, IPSEC_DIR_INBOUND);
  113         } else {
  114                 sp = ipsec_getpolicybyaddr(m, IPSEC_DIR_INBOUND,
  115                                            IP_FORWARDING, &error);
  116         }
  117         if (sp == NULL) {       /* NB: can happen if error */
  118                 splx(s);
  119                 /*XXX error stat???*/
  120                 DPRINTF(("ip_input: no SP for forwarding\n"));  /*XXX*/
  121                 return 1;
  122         }
  123 
  124         /*
  125          * Check security policy against packet attributes.
  126          */
  127         error = ipsec_in_reject(sp, m);
  128         KEY_FREESP(&sp);
  129         splx(s);
  130         if (error) {
  131                 ip6stat.ip6s_cantforward++;
  132                 return 1;
  133         }
  134 #endif /* IPSEC */
  135         return 0;
  136 }
  137 
  138 /*
  139  * Check if protocol type doesn't have a further header and do IPSEC
  140  * decryption or reject right now.  Protocols with further headers get
  141  * their IPSEC treatment within the protocol specific processing.
  142  * Called from ip_input().
  143  * 1 = drop packet, 0 = continue processing packet.
  144  */
  145 int
  146 ip6_ipsec_input(struct mbuf *m, int nxt)
  147 {
  148 #ifdef IPSEC
  149         struct m_tag *mtag;
  150         struct tdb_ident *tdbi;
  151         struct secpolicy *sp;
  152         int s, error;
  153         /*
  154          * enforce IPsec policy checking if we are seeing last header.
  155          * note that we do not visit this with protocols with pcb layer
  156          * code - like udp/tcp/raw ip.
  157          */
  158         if ((inet6sw[ip6_protox[nxt]].pr_flags & PR_LASTHDR) != 0 &&
  159             ipsec6_in_reject(m, NULL)) {
  160 
  161                 /*
  162                  * Check if the packet has already had IPsec processing
  163                  * done.  If so, then just pass it along.  This tag gets
  164                  * set during AH, ESP, etc. input handling, before the
  165                  * packet is returned to the ip input queue for delivery.
  166                  */
  167                 mtag = m_tag_find(m, PACKET_TAG_IPSEC_IN_DONE, NULL);
  168                 s = splnet();
  169                 if (mtag != NULL) {
  170                         tdbi = (struct tdb_ident *)(mtag + 1);
  171                         sp = ipsec_getpolicy(tdbi, IPSEC_DIR_INBOUND);
  172                 } else {
  173                         sp = ipsec_getpolicybyaddr(m, IPSEC_DIR_INBOUND,
  174                                                    IP_FORWARDING, &error);
  175                 }
  176                 if (sp != NULL) {
  177                         /*
  178                          * Check security policy against packet attributes.
  179                          */
  180                         error = ipsec_in_reject(sp, m);
  181                         KEY_FREESP(&sp);
  182                 } else {
  183                         /* XXX error stat??? */
  184                         error = EINVAL;
  185                         DPRINTF(("ip_input: no SP, packet discarded\n"));/*XXX*/
  186                         return 1;
  187                 }
  188                 splx(s);
  189                 if (error)
  190                         return 1;
  191         }
  192 #endif /* IPSEC */
  193         return 0;
  194 }
  195 
  196 /*
  197  * Called from ip6_output().
  198  * 1 = drop packet, 0 = continue processing packet,
  199  * -1 = packet was reinjected and stop processing packet
  200  */
  201 
  202 int
  203 ip6_ipsec_output(struct mbuf **m, struct inpcb *inp, int *flags, int *error,
  204     struct ifnet **ifp, struct secpolicy **sp)
  205 {
  206 #ifdef IPSEC
  207         struct tdb_ident *tdbi;
  208         struct m_tag *mtag;
  209         /* XXX int s; */
  210         if (sp == NULL)
  211                 return 1;
  212         mtag = m_tag_find(*m, PACKET_TAG_IPSEC_PENDING_TDB, NULL);
  213         if (mtag != NULL) {
  214                 tdbi = (struct tdb_ident *)(mtag + 1);
  215                 *sp = ipsec_getpolicy(tdbi, IPSEC_DIR_OUTBOUND);
  216                 if (*sp == NULL)
  217                         *error = -EINVAL;       /* force silent drop */
  218                 m_tag_delete(*m, mtag);
  219         } else {
  220                 *sp = ipsec4_checkpolicy(*m, IPSEC_DIR_OUTBOUND, *flags,
  221                                         error, inp);
  222         }
  223 
  224         /*
  225          * There are four return cases:
  226          *    sp != NULL                    apply IPsec policy
  227          *    sp == NULL, error == 0        no IPsec handling needed
  228          *    sp == NULL, error == -EINVAL  discard packet w/o error
  229          *    sp == NULL, error != 0        discard packet, report error
  230          */
  231         if (*sp != NULL) {
  232                 /* Loop detection, check if ipsec processing already done */
  233                 KASSERT((*sp)->req != NULL, ("ip_output: no ipsec request"));
  234                 for (mtag = m_tag_first(*m); mtag != NULL;
  235                      mtag = m_tag_next(*m, mtag)) {
  236                         if (mtag->m_tag_cookie != MTAG_ABI_COMPAT)
  237                                 continue;
  238                         if (mtag->m_tag_id != PACKET_TAG_IPSEC_OUT_DONE &&
  239                             mtag->m_tag_id != PACKET_TAG_IPSEC_OUT_CRYPTO_NEEDED)
  240                                 continue;
  241                         /*
  242                          * Check if policy has an SA associated with it.
  243                          * This can happen when an SP has yet to acquire
  244                          * an SA; e.g. on first reference.  If it occurs,
  245                          * then we let ipsec4_process_packet do its thing.
  246                          */
  247                         if ((*sp)->req->sav == NULL)
  248                                 break;
  249                         tdbi = (struct tdb_ident *)(mtag + 1);
  250                         if (tdbi->spi == (*sp)->req->sav->spi &&
  251                             tdbi->proto == (*sp)->req->sav->sah->saidx.proto &&
  252                             bcmp(&tdbi->dst, &(*sp)->req->sav->sah->saidx.dst,
  253                                  sizeof (union sockaddr_union)) == 0) {
  254                                 /*
  255                                  * No IPsec processing is needed, free
  256                                  * reference to SP.
  257                                  *
  258                                  * NB: null pointer to avoid free at
  259                                  *     done: below.
  260                                  */
  261                                 KEY_FREESP(sp), *sp = NULL;
  262                                 /* XXX splx(s); */
  263                                 goto done;
  264                         }
  265                 }
  266 
  267                 /*
  268                  * Do delayed checksums now because we send before
  269                  * this is done in the normal processing path.
  270                  */
  271                 if ((*m)->m_pkthdr.csum_flags & CSUM_DELAY_DATA) {
  272                         in_delayed_cksum(*m);
  273                         (*m)->m_pkthdr.csum_flags &= ~CSUM_DELAY_DATA;
  274                 }
  275 
  276                 /*
  277                  * Preserve KAME behaviour: ENOENT can be returned
  278                  * when an SA acquire is in progress.  Don't propagate
  279                  * this to user-level; it confuses applications.
  280                  *
  281                  * XXX this will go away when the SADB is redone.
  282                  */
  283                 if (*error == ENOENT)
  284                         *error = 0;
  285                 goto do_ipsec;
  286         } else {        /* sp == NULL */
  287                 if (*error != 0) {
  288                         /*
  289                          * Hack: -EINVAL is used to signal that a packet
  290                          * should be silently discarded.  This is typically
  291                          * because we asked key management for an SA and
  292                          * it was delayed (e.g. kicked up to IKE).
  293                          */
  294                         if (*error == -EINVAL)
  295                                 *error = 0;
  296                         goto bad;
  297                 } else {
  298                         /* No IPsec processing for this packet. */
  299                 }
  300         }
  301 done:
  302         return 0;
  303 do_ipsec:
  304         return -1;
  305 bad:
  306         return 1;
  307 #endif /* IPSEC */
  308         return 0;
  309 }
  310 
  311 #if 0
  312 /*
  313  * Compute the MTU for a forwarded packet that gets IPSEC encapsulated.
  314  * Called from ip_forward().
  315  * Returns MTU suggestion for ICMP needfrag reply.
  316  */
  317 int
  318 ip6_ipsec_mtu(struct mbuf *m)
  319 {
  320         int mtu = 0;
  321         /*
  322          * If the packet is routed over IPsec tunnel, tell the
  323          * originator the tunnel MTU.
  324          *      tunnel MTU = if MTU - sizeof(IP) - ESP/AH hdrsiz
  325          * XXX quickhack!!!
  326          */
  327 #ifdef IPSEC
  328         struct secpolicy *sp = NULL;
  329         int ipsecerror;
  330         int ipsechdr;
  331         struct route *ro;
  332         sp = ipsec_getpolicybyaddr(m,
  333                                    IPSEC_DIR_OUTBOUND,
  334                                    IP_FORWARDING,
  335                                    &ipsecerror);
  336         if (sp != NULL) {
  337                 /* count IPsec header size */
  338                 ipsechdr = ipsec4_hdrsiz(m,
  339                                          IPSEC_DIR_OUTBOUND,
  340                                          NULL);
  341 
  342                 /*
  343                  * find the correct route for outer IPv4
  344                  * header, compute tunnel MTU.
  345                  */
  346                 if (sp->req != NULL &&
  347                     sp->req->sav != NULL &&
  348                     sp->req->sav->sah != NULL) {
  349                         ro = &sp->req->sav->sah->route_cache.sa_route;
  350                         if (ro->ro_rt && ro->ro_rt->rt_ifp) {
  351                                 mtu =
  352                                     ro->ro_rt->rt_rmx.rmx_mtu ?
  353                                     ro->ro_rt->rt_rmx.rmx_mtu :
  354                                     ro->ro_rt->rt_ifp->if_mtu;
  355                                 mtu -= ipsechdr;
  356                         }
  357                 }
  358                 KEY_FREESP(&sp);
  359         }
  360 #endif /* IPSEC */
  361         /* XXX else case missing. */
  362         return mtu;
  363 }
  364 #endif
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FreeBSD/Linux Kernel Cross Reference sys/netinet6/ip6_ipsec.c

FreeBSD/Linux Kernel Cross Reference
sys/netinet6/ip6_ipsec.c
