The Design and Implementation of the FreeBSD Operating System, Second Edition
Now available: The Design and Implementation of the FreeBSD Operating System (Second Edition)


[ source navigation ] [ diff markup ] [ identifier search ] [ freetext search ] [ file search ] [ list types ] [ track identifier ]

FreeBSD/Linux Kernel Cross Reference
sys/netinet/ip_ipsec.c

Version: -  FREEBSD  -  FREEBSD-13-STABLE  -  FREEBSD-13-0  -  FREEBSD-12-STABLE  -  FREEBSD-12-0  -  FREEBSD-11-STABLE  -  FREEBSD-11-0  -  FREEBSD-10-STABLE  -  FREEBSD-10-0  -  FREEBSD-9-STABLE  -  FREEBSD-9-0  -  FREEBSD-8-STABLE  -  FREEBSD-8-0  -  FREEBSD-7-STABLE  -  FREEBSD-7-0  -  FREEBSD-6-STABLE  -  FREEBSD-6-0  -  FREEBSD-5-STABLE  -  FREEBSD-5-0  -  FREEBSD-4-STABLE  -  FREEBSD-3-STABLE  -  FREEBSD22  -  l41  -  OPENBSD  -  linux-2.6  -  MK84  -  PLAN9  -  xnu-8792 
SearchContext: -  none  -  3  -  10 

    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/netinet/ip_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/errno.h>
   38 #include <sys/kernel.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 #include <netinet/ip_ipsec.h>
   57 
   58 #include <machine/in_cksum.h>
   59 
   60 #ifdef IPSEC
   61 #include <netipsec/ipsec.h>
   62 #include <netipsec/xform.h>
   63 #include <netipsec/key.h>
   64 #endif /*IPSEC*/
   65 
   66 extern  struct protosw inetsw[];
   67 
   68 /*
   69  * Check if we have to jump over firewall processing for this packet.
   70  * Called from ip_input().
   71  * 1 = jump over firewall, 0 = packet goes through firewall.
   72  */
   73 int
   74 ip_ipsec_filtertunnel(struct mbuf *m)
   75 {
   76 #if defined(IPSEC) && !defined(IPSEC_FILTERTUNNEL)
   77         /*
   78          * Bypass packet filtering for packets from a tunnel.
   79          */
   80         if (m_tag_find(m, PACKET_TAG_IPSEC_IN_DONE, NULL) != NULL)
   81                 return 1;
   82 #endif
   83         return 0;
   84 }
   85 
   86 /*
   87  * Check if this packet has an active SA and needs to be dropped instead
   88  * of forwarded.
   89  * Called from ip_input().
   90  * 1 = drop packet, 0 = forward packet.
   91  */
   92 int
   93 ip_ipsec_fwd(struct mbuf *m)
   94 {
   95 #ifdef IPSEC
   96         struct m_tag *mtag;
   97         struct tdb_ident *tdbi;
   98         struct secpolicy *sp;
   99         int s, error;
  100 
  101         mtag = m_tag_find(m, PACKET_TAG_IPSEC_IN_DONE, NULL);
  102         s = splnet();
  103         if (mtag != NULL) {
  104                 tdbi = (struct tdb_ident *)(mtag + 1);
  105                 sp = ipsec_getpolicy(tdbi, IPSEC_DIR_INBOUND);
  106         } else {
  107                 sp = ipsec_getpolicybyaddr(m, IPSEC_DIR_INBOUND,
  108                                            IP_FORWARDING, &error);   
  109         }
  110         if (sp == NULL) {       /* NB: can happen if error */
  111                 splx(s);
  112                 /*XXX error stat???*/
  113                 DPRINTF(("ip_input: no SP for forwarding\n"));  /*XXX*/
  114                 return 1;
  115         }
  116 
  117         /*
  118          * Check security policy against packet attributes.
  119          */
  120         error = ipsec_in_reject(sp, m);
  121         KEY_FREESP(&sp);
  122         splx(s);
  123         if (error) {
  124                 ipstat.ips_cantforward++;
  125                 return 1;
  126         }
  127 #endif /* IPSEC */
  128         return 0;
  129 }
  130 
  131 /*
  132  * Check if protocol type doesn't have a further header and do IPSEC
  133  * decryption or reject right now.  Protocols with further headers get
  134  * their IPSEC treatment within the protocol specific processing.
  135  * Called from ip_input().
  136  * 1 = drop packet, 0 = continue processing packet.
  137  */
  138 int
  139 ip_ipsec_input(struct mbuf *m)
  140 {
  141         struct ip *ip = mtod(m, struct ip *);
  142 #ifdef IPSEC
  143         struct m_tag *mtag;
  144         struct tdb_ident *tdbi;
  145         struct secpolicy *sp;
  146         int s, error;
  147         /*
  148          * enforce IPsec policy checking if we are seeing last header.
  149          * note that we do not visit this with protocols with pcb layer
  150          * code - like udp/tcp/raw ip.
  151          */
  152         if ((inetsw[ip_protox[ip->ip_p]].pr_flags & PR_LASTHDR) != 0) {
  153                 /*
  154                  * Check if the packet has already had IPsec processing
  155                  * done.  If so, then just pass it along.  This tag gets
  156                  * set during AH, ESP, etc. input handling, before the
  157                  * packet is returned to the ip input queue for delivery.
  158                  */ 
  159                 mtag = m_tag_find(m, PACKET_TAG_IPSEC_IN_DONE, NULL);
  160                 s = splnet();
  161                 if (mtag != NULL) {
  162                         tdbi = (struct tdb_ident *)(mtag + 1);
  163                         sp = ipsec_getpolicy(tdbi, IPSEC_DIR_INBOUND);
  164                 } else {
  165                         sp = ipsec_getpolicybyaddr(m, IPSEC_DIR_INBOUND,
  166                                                    IP_FORWARDING, &error);   
  167                 }
  168                 if (sp != NULL) {
  169                         /*
  170                          * Check security policy against packet attributes.
  171                          */
  172                         error = ipsec_in_reject(sp, m);
  173                         KEY_FREESP(&sp);
  174                 } else {
  175                         /* XXX error stat??? */
  176                         error = EINVAL;
  177                         DPRINTF(("ip_input: no SP, packet discarded\n"));/*XXX*/
  178                         return 1;
  179                 }
  180                 splx(s);
  181                 if (error)
  182                         return 1;
  183         }
  184 #endif /* IPSEC */
  185         return 0;
  186 }
  187 
  188 /*
  189  * Compute the MTU for a forwarded packet that gets IPSEC encapsulated.
  190  * Called from ip_forward().
  191  * Returns MTU suggestion for ICMP needfrag reply.
  192  */
  193 int
  194 ip_ipsec_mtu(struct mbuf *m, int mtu)
  195 {
  196         /*
  197          * If the packet is routed over IPsec tunnel, tell the
  198          * originator the tunnel MTU.
  199          *      tunnel MTU = if MTU - sizeof(IP) - ESP/AH hdrsiz
  200          * XXX quickhack!!!
  201          */
  202         struct secpolicy *sp = NULL;
  203         int ipsecerror;
  204         int ipsechdr;
  205         struct route *ro;
  206         sp = ipsec_getpolicybyaddr(m,
  207                                    IPSEC_DIR_OUTBOUND,
  208                                    IP_FORWARDING,
  209                                    &ipsecerror);
  210         if (sp != NULL) {
  211                 /* count IPsec header size */
  212                 ipsechdr = ipsec4_hdrsiz(m,
  213                                          IPSEC_DIR_OUTBOUND,
  214                                          NULL);
  215 
  216                 /*
  217                  * find the correct route for outer IPv4
  218                  * header, compute tunnel MTU.
  219                  */
  220                 if (sp->req != NULL &&
  221                     sp->req->sav != NULL &&
  222                     sp->req->sav->sah != NULL) {
  223                         ro = &sp->req->sav->sah->route_cache.sa_route;
  224                         if (ro->ro_rt && ro->ro_rt->rt_ifp) {
  225                                 mtu =
  226                                     ro->ro_rt->rt_rmx.rmx_mtu ?
  227                                     ro->ro_rt->rt_rmx.rmx_mtu :
  228                                     ro->ro_rt->rt_ifp->if_mtu;
  229                                 mtu -= ipsechdr;
  230                         }
  231                 }
  232                 KEY_FREESP(&sp);
  233         }
  234         return mtu;
  235 }
  236 
  237 /*
  238  * 
  239  * Called from ip_output().
  240  * 1 = drop packet, 0 = continue processing packet,
  241  * -1 = packet was reinjected and stop processing packet
  242  */
  243 int
  244 ip_ipsec_output(struct mbuf **m, struct inpcb *inp, int *flags, int *error,
  245     struct route **ro, struct route *iproute, struct sockaddr_in **dst,
  246     struct in_ifaddr **ia, struct ifnet **ifp)
  247 {
  248 #ifdef IPSEC
  249         struct secpolicy *sp = NULL;
  250         struct ip *ip = mtod(*m, struct ip *);
  251         struct tdb_ident *tdbi;
  252         struct m_tag *mtag;
  253         int s;
  254         /*
  255          * Check the security policy (SP) for the packet and, if
  256          * required, do IPsec-related processing.  There are two
  257          * cases here; the first time a packet is sent through
  258          * it will be untagged and handled by ipsec4_checkpolicy.
  259          * If the packet is resubmitted to ip_output (e.g. after
  260          * AH, ESP, etc. processing), there will be a tag to bypass
  261          * the lookup and related policy checking.
  262          */
  263         mtag = m_tag_find(*m, PACKET_TAG_IPSEC_PENDING_TDB, NULL);
  264         s = splnet();
  265         if (mtag != NULL) {
  266                 tdbi = (struct tdb_ident *)(mtag + 1);
  267                 sp = ipsec_getpolicy(tdbi, IPSEC_DIR_OUTBOUND);
  268                 if (sp == NULL)
  269                         *error = -EINVAL;       /* force silent drop */
  270                 m_tag_delete(*m, mtag);
  271         } else {
  272                 sp = ipsec4_checkpolicy(*m, IPSEC_DIR_OUTBOUND, *flags,
  273                                         error, inp);
  274         }
  275         /*
  276          * There are four return cases:
  277          *    sp != NULL                    apply IPsec policy
  278          *    sp == NULL, error == 0        no IPsec handling needed
  279          *    sp == NULL, error == -EINVAL  discard packet w/o error
  280          *    sp == NULL, error != 0        discard packet, report error
  281          */
  282         if (sp != NULL) {
  283                 /* Loop detection, check if ipsec processing already done */
  284                 KASSERT(sp->req != NULL, ("ip_output: no ipsec request"));
  285                 for (mtag = m_tag_first(*m); mtag != NULL;
  286                      mtag = m_tag_next(*m, mtag)) {
  287                         if (mtag->m_tag_cookie != MTAG_ABI_COMPAT)
  288                                 continue;
  289                         if (mtag->m_tag_id != PACKET_TAG_IPSEC_OUT_DONE &&
  290                             mtag->m_tag_id != PACKET_TAG_IPSEC_OUT_CRYPTO_NEEDED)
  291                                 continue;
  292                         /*
  293                          * Check if policy has an SA associated with it.
  294                          * This can happen when an SP has yet to acquire
  295                          * an SA; e.g. on first reference.  If it occurs,
  296                          * then we let ipsec4_process_packet do its thing.
  297                          */
  298                         if (sp->req->sav == NULL)
  299                                 break;
  300                         tdbi = (struct tdb_ident *)(mtag + 1);
  301                         if (tdbi->spi == sp->req->sav->spi &&
  302                             tdbi->proto == sp->req->sav->sah->saidx.proto &&
  303                             bcmp(&tdbi->dst, &sp->req->sav->sah->saidx.dst,
  304                                  sizeof (union sockaddr_union)) == 0) {
  305                                 /*
  306                                  * No IPsec processing is needed, free
  307                                  * reference to SP.
  308                                  *
  309                                  * NB: null pointer to avoid free at
  310                                  *     done: below.
  311                                  */
  312                                 KEY_FREESP(&sp), sp = NULL;
  313                                 splx(s);
  314                                 goto done;
  315                         }
  316                 }
  317 
  318                 /*
  319                  * Do delayed checksums now because we send before
  320                  * this is done in the normal processing path.
  321                  */
  322                 if ((*m)->m_pkthdr.csum_flags & CSUM_DELAY_DATA) {
  323                         in_delayed_cksum(*m);
  324                         (*m)->m_pkthdr.csum_flags &= ~CSUM_DELAY_DATA;
  325                 }
  326 
  327                 ip->ip_len = htons(ip->ip_len);
  328                 ip->ip_off = htons(ip->ip_off);
  329 
  330                 /* NB: callee frees mbuf */
  331                 *error = ipsec4_process_packet(*m, sp->req, *flags, 0);
  332                 if (*error == EJUSTRETURN) {
  333                         /*
  334                          * We had a SP with a level of 'use' and no SA. We
  335                          * will just continue to process the packet without
  336                          * IPsec processing and return without error.
  337                          */
  338                         *error = 0;
  339                         ip->ip_len = ntohs(ip->ip_len);
  340                         ip->ip_off = ntohs(ip->ip_off);
  341                         goto done;
  342                 }
  343                 /*
  344                  * Preserve KAME behaviour: ENOENT can be returned
  345                  * when an SA acquire is in progress.  Don't propagate
  346                  * this to user-level; it confuses applications.
  347                  *
  348                  * XXX this will go away when the SADB is redone.
  349                  */
  350                 if (*error == ENOENT)
  351                         *error = 0;
  352                 splx(s);
  353                 goto reinjected;
  354         } else {        /* sp == NULL */
  355                 splx(s);
  356 
  357                 if (*error != 0) {
  358                         /*
  359                          * Hack: -EINVAL is used to signal that a packet
  360                          * should be silently discarded.  This is typically
  361                          * because we asked key management for an SA and
  362                          * it was delayed (e.g. kicked up to IKE).
  363                          */
  364                         if (*error == -EINVAL)
  365                                 *error = 0;
  366                         goto bad;
  367                 } else {
  368                         /* No IPsec processing for this packet. */
  369                 }
  370 #ifdef notyet
  371                 /*
  372                  * If deferred crypto processing is needed, check that
  373                  * the interface supports it.
  374                  */ 
  375                 mtag = m_tag_find(*m, PACKET_TAG_IPSEC_OUT_CRYPTO_NEEDED, NULL);
  376                 if (mtag != NULL && ((*ifp)->if_capenable & IFCAP_IPSEC) == 0) {
  377                         /* notify IPsec to do its own crypto */
  378                         ipsp_skipcrypto_unmark((struct tdb_ident *)(mtag + 1));
  379                         *error = EHOSTUNREACH;
  380                         goto bad;
  381                 }
  382 #endif
  383         }
  384 done:
  385         if (sp != NULL)
  386                 KEY_FREESP(&sp);
  387         return 0;
  388 reinjected:
  389         if (sp != NULL)
  390                 KEY_FREESP(&sp);
  391         return -1;
  392 bad:
  393         if (sp != NULL)
  394                 KEY_FREESP(&sp);
  395         return 1;
  396 #endif /* IPSEC */
  397         return 0;
  398 }

Cache object: 580e14c85d566fe715241657f1b7234a


[ source navigation ] [ diff markup ] [ identifier search ] [ freetext search ] [ file search ] [ list types ] [ track identifier ]


This page is part of the FreeBSD/Linux Linux Kernel Cross-Reference, and was automatically generated using a modified version of the LXR engine.