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/11.0/sys/netinet6/ip6_ipsec.c 288418 2015-09-30 08:16:33Z ae $");
   32 
   33 #include "opt_inet.h"
   34 #include "opt_sctp.h"
   35 #include "opt_ipsec.h"
   36 
   37 #include <sys/param.h>
   38 #include <sys/systm.h>
   39 #include <sys/kernel.h>
   40 #include <sys/mac.h>
   41 #include <sys/malloc.h>
   42 #include <sys/mbuf.h>
   43 #include <sys/protosw.h>
   44 #include <sys/socket.h>
   45 #include <sys/socketvar.h>
   46 #include <sys/sysctl.h>
   47 #include <sys/syslog.h>
   48 
   49 #include <net/if.h>
   50 #include <net/if_var.h>
   51 #include <net/vnet.h>
   52 
   53 #include <netinet/in.h>
   54 #include <netinet/in_systm.h>
   55 #include <netinet/in_var.h>
   56 #include <netinet/ip.h>
   57 #include <netinet/ip6.h>
   58 #include <netinet/in_pcb.h>
   59 #include <netinet/ip_var.h>
   60 #include <netinet/ip_options.h>
   61 #ifdef SCTP
   62 #include <netinet/sctp_crc32.h>
   63 #endif
   64 
   65 #include <machine/in_cksum.h>
   66 
   67 #include <netipsec/ipsec.h>
   68 #include <netipsec/ipsec6.h>
   69 #include <netipsec/xform.h>
   70 #include <netipsec/key.h>
   71 #ifdef IPSEC_DEBUG
   72 #include <netipsec/key_debug.h>
   73 #else
   74 #define KEYDEBUG(lev,arg)
   75 #endif
   76 
   77 #include <netinet6/ip6_ipsec.h>
   78 #include <netinet6/ip6_var.h>
   79 
   80 extern  struct protosw inet6sw[];
   81 
   82 #ifdef IPSEC_FILTERTUNNEL
   83 static VNET_DEFINE(int, ip6_ipsec6_filtertunnel) = 1;
   84 #else
   85 static VNET_DEFINE(int, ip6_ipsec6_filtertunnel) = 0;
   86 #endif
   87 #define V_ip6_ipsec6_filtertunnel       VNET(ip6_ipsec6_filtertunnel)
   88 
   89 SYSCTL_DECL(_net_inet6_ipsec6);
   90 SYSCTL_INT(_net_inet6_ipsec6, OID_AUTO, filtertunnel,
   91         CTLFLAG_VNET | CTLFLAG_RW, &VNET_NAME(ip6_ipsec6_filtertunnel),  0,
   92         "If set filter packets from an IPsec tunnel.");
   93 
   94 /*
   95  * Check if we have to jump over firewall processing for this packet.
   96  * Called from ip6_input().
   97  * 1 = jump over firewall, 0 = packet goes through firewall.
   98  */
   99 int
  100 ip6_ipsec_filtertunnel(struct mbuf *m)
  101 {
  102 
  103         /*
  104          * Bypass packet filtering for packets previously handled by IPsec.
  105          */
  106         if (!V_ip6_ipsec6_filtertunnel &&
  107             m_tag_find(m, PACKET_TAG_IPSEC_IN_DONE, NULL) != NULL)
  108                 return (1);
  109         return (0);
  110 }
  111 
  112 /*
  113  * Check if this packet has an active SA and needs to be dropped instead
  114  * of forwarded.
  115  * Called from ip6_forward().
  116  * 1 = drop packet, 0 = forward packet.
  117  */
  118 int
  119 ip6_ipsec_fwd(struct mbuf *m)
  120 {
  121 
  122         return (ipsec6_in_reject(m, NULL));
  123 }
  124 
  125 /*
  126  * Check if protocol type doesn't have a further header and do IPSEC
  127  * decryption or reject right now.  Protocols with further headers get
  128  * their IPSEC treatment within the protocol specific processing.
  129  * Called from ip6_input().
  130  * 1 = drop packet, 0 = continue processing packet.
  131  */
  132 int
  133 ip6_ipsec_input(struct mbuf *m, int nxt)
  134 {
  135 
  136         /*
  137          * enforce IPsec policy checking if we are seeing last header.
  138          * note that we do not visit this with protocols with pcb layer
  139          * code - like udp/tcp/raw ip.
  140          */
  141         if ((inet6sw[ip6_protox[nxt]].pr_flags & PR_LASTHDR) != 0)
  142                 return (ipsec6_in_reject(m, NULL));
  143         return (0);
  144 }
  145 
  146 /*
  147  * Called from ip6_output().
  148  * 1 = drop packet, 0 = continue processing packet,
  149  * -1 = packet was reinjected and stop processing packet
  150  */
  151 
  152 int
  153 ip6_ipsec_output(struct mbuf **m, struct inpcb *inp, int *error)
  154 {
  155         struct secpolicy *sp;
  156 
  157         /*
  158          * Check the security policy (SP) for the packet and, if
  159          * required, do IPsec-related processing.  There are two
  160          * cases here; the first time a packet is sent through
  161          * it will be untagged and handled by ipsec4_checkpolicy.
  162          * If the packet is resubmitted to ip6_output (e.g. after
  163          * AH, ESP, etc. processing), there will be a tag to bypass
  164          * the lookup and related policy checking.
  165          */
  166         if (m_tag_find(*m, PACKET_TAG_IPSEC_OUT_DONE, NULL) != NULL) {
  167                 *error = 0;
  168                 return (0);
  169         }
  170         sp = ipsec4_checkpolicy(*m, IPSEC_DIR_OUTBOUND, error, inp);
  171         /*
  172          * There are four return cases:
  173          *    sp != NULL                    apply IPsec policy
  174          *    sp == NULL, error == 0        no IPsec handling needed
  175          *    sp == NULL, error == -EINVAL  discard packet w/o error
  176          *    sp == NULL, error != 0        discard packet, report error
  177          */
  178         if (sp != NULL) {
  179                 /*
  180                  * Do delayed checksums now because we send before
  181                  * this is done in the normal processing path.
  182                  */
  183 #ifdef INET
  184                 if ((*m)->m_pkthdr.csum_flags & CSUM_DELAY_DATA) {
  185                         in_delayed_cksum(*m);
  186                         (*m)->m_pkthdr.csum_flags &= ~CSUM_DELAY_DATA;
  187                 }
  188 #endif
  189                 if ((*m)->m_pkthdr.csum_flags & CSUM_DELAY_DATA_IPV6) {
  190                         in6_delayed_cksum(*m, (*m)->m_pkthdr.len - sizeof(struct ip6_hdr),
  191                                                         sizeof(struct ip6_hdr));
  192                         (*m)->m_pkthdr.csum_flags &= ~CSUM_DELAY_DATA_IPV6;
  193                 }
  194 #ifdef SCTP
  195                 if ((*m)->m_pkthdr.csum_flags & CSUM_SCTP_IPV6) {
  196                         sctp_delayed_cksum(*m, sizeof(struct ip6_hdr));
  197                         (*m)->m_pkthdr.csum_flags &= ~CSUM_SCTP_IPV6;
  198                 }
  199 #endif
  200 
  201                 /* NB: callee frees mbuf */
  202                 *error = ipsec6_process_packet(*m, sp->req);
  203                 KEY_FREESP(&sp);
  204                 if (*error == EJUSTRETURN) {
  205                         /*
  206                          * We had a SP with a level of 'use' and no SA. We
  207                          * will just continue to process the packet without
  208                          * IPsec processing.
  209                          */
  210                         *error = 0;
  211                         goto done;
  212                 }
  213 
  214                 /*
  215                  * Preserve KAME behaviour: ENOENT can be returned
  216                  * when an SA acquire is in progress.  Don't propagate
  217                  * this to user-level; it confuses applications.
  218                  *
  219                  * XXX this will go away when the SADB is redone.
  220                  */
  221                 if (*error == ENOENT)
  222                         *error = 0;
  223                 goto reinjected;
  224         } else {        /* sp == NULL */
  225                 if (*error != 0) {
  226                         /*
  227                          * Hack: -EINVAL is used to signal that a packet
  228                          * should be silently discarded.  This is typically
  229                          * because we asked key management for an SA and
  230                          * it was delayed (e.g. kicked up to IKE).
  231                          */
  232                         if (*error == -EINVAL)
  233                                 *error = 0;
  234                         goto bad;
  235                 }
  236                 /* No IPsec processing for this packet. */
  237         }
  238 done:
  239         return (0);
  240 reinjected:
  241         return (-1);
  242 bad:
  243         if (sp != NULL)
  244                 KEY_FREESP(&sp);
  245         return (1);
  246 }
  247 
  248 #if 0
  249 /*
  250  * Compute the MTU for a forwarded packet that gets IPSEC encapsulated.
  251  * Called from ip_forward().
  252  * Returns MTU suggestion for ICMP needfrag reply.
  253  */
  254 int
  255 ip6_ipsec_mtu(struct mbuf *m)
  256 {
  257         int mtu = 0;
  258         /*
  259          * If the packet is routed over IPsec tunnel, tell the
  260          * originator the tunnel MTU.
  261          *      tunnel MTU = if MTU - sizeof(IP) - ESP/AH hdrsiz
  262          * XXX quickhack!!!
  263          */
  264 #ifdef IPSEC
  265         struct secpolicy *sp = NULL;
  266         int ipsecerror;
  267         int ipsechdr;
  268         struct route *ro;
  269         sp = ipsec_getpolicybyaddr(m,
  270                                    IPSEC_DIR_OUTBOUND,
  271                                    IP_FORWARDING,
  272                                    &ipsecerror);
  273         if (sp != NULL) {
  274                 /* count IPsec header size */
  275                 ipsechdr = ipsec_hdrsiz(m, IPSEC_DIR_OUTBOUND, NULL);
  276 
  277                 /*
  278                  * find the correct route for outer IPv4
  279                  * header, compute tunnel MTU.
  280                  */
  281                 if (sp->req != NULL &&
  282                     sp->req->sav != NULL &&
  283                     sp->req->sav->sah != NULL) {
  284                         ro = &sp->req->sav->sah->route_cache.sa_route;
  285                         if (ro->ro_rt && ro->ro_rt->rt_ifp) {
  286                                 mtu = ro->ro_rt->rt_mtu ? ro->ro_rt->rt_mtu :
  287                                     ro->ro_rt->rt_ifp->if_mtu;
  288                                 mtu -= ipsechdr;
  289                         }
  290                 }
  291                 KEY_FREESP(&sp);
  292         }
  293 #endif /* IPSEC */
  294         /* XXX else case missing. */
  295         return mtu;
  296 }
  297 #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
