ipsec_input.c

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    1 /*      $FreeBSD: releng/6.4/sys/netipsec/ipsec_input.c 176951 2008-03-08 18:56:22Z bz $        */
    2 /*      $OpenBSD: ipsec_input.c,v 1.63 2003/02/20 18:35:43 deraadt Exp $        */
    3 /*-
    4  * The authors of this code are John Ioannidis (ji@tla.org),
    5  * Angelos D. Keromytis (kermit@csd.uch.gr) and
    6  * Niels Provos (provos@physnet.uni-hamburg.de).
    7  *
    8  * This code was written by John Ioannidis for BSD/OS in Athens, Greece,
    9  * in November 1995.
   10  *
   11  * Ported to OpenBSD and NetBSD, with additional transforms, in December 1996,
   12  * by Angelos D. Keromytis.
   13  *
   14  * Additional transforms and features in 1997 and 1998 by Angelos D. Keromytis
   15  * and Niels Provos.
   16  *
   17  * Additional features in 1999 by Angelos D. Keromytis.
   18  *
   19  * Copyright (C) 1995, 1996, 1997, 1998, 1999 by John Ioannidis,
   20  * Angelos D. Keromytis and Niels Provos.
   21  * Copyright (c) 2001, Angelos D. Keromytis.
   22  *
   23  * Permission to use, copy, and modify this software with or without fee
   24  * is hereby granted, provided that this entire notice is included in
   25  * all copies of any software which is or includes a copy or
   26  * modification of this software.
   27  * You may use this code under the GNU public license if you so wish. Please
   28  * contribute changes back to the authors under this freer than GPL license
   29  * so that we may further the use of strong encryption without limitations to
   30  * all.
   31  *
   32  * THIS SOFTWARE IS BEING PROVIDED "AS IS", WITHOUT ANY EXPRESS OR
   33  * IMPLIED WARRANTY. IN PARTICULAR, NONE OF THE AUTHORS MAKES ANY
   34  * REPRESENTATION OR WARRANTY OF ANY KIND CONCERNING THE
   35  * MERCHANTABILITY OF THIS SOFTWARE OR ITS FITNESS FOR ANY PARTICULAR
   36  * PURPOSE.
   37  */
   38 
   39 /*
   40  * IPsec input processing.
   41  */
   42 
   43 #include "opt_inet.h"
   44 #include "opt_inet6.h"
   45 #include "opt_ipsec.h"
   46 #include "opt_enc.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 
   58 #include <net/if.h>
   59 #include <net/pfil.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 <netipsec/ipsec.h>
   79 #ifdef INET6
   80 #include <netipsec/ipsec6.h>
   81 #endif
   82 #include <netipsec/ah_var.h>
   83 #include <netipsec/esp.h>
   84 #include <netipsec/esp_var.h>
   85 #include <netipsec/ipcomp_var.h>
   86 
   87 #include <netipsec/key.h>
   88 #include <netipsec/keydb.h>
   89 
   90 #include <netipsec/xform.h>
   91 #include <netinet6/ip6protosw.h>
   92 
   93 #include <machine/in_cksum.h>
   94 #include <machine/stdarg.h>
   95 
   96 #define IPSEC_ISTAT(p,x,y,z) ((p) == IPPROTO_ESP ? (x)++ : \
   97                             (p) == IPPROTO_AH ? (y)++ : (z)++)
   98 
   99 static void ipsec4_common_ctlinput(int, struct sockaddr *, void *, int);
  100 
  101 /*
  102  * ipsec_common_input gets called when an IPsec-protected packet
  103  * is received by IPv4 or IPv6.  It's job is to find the right SA
  104  * and call the appropriate transform.  The transform callback
  105  * takes care of further processing (like ingress filtering).
  106  */
  107 static int
  108 ipsec_common_input(struct mbuf *m, int skip, int protoff, int af, int sproto)
  109 {
  110         union sockaddr_union dst_address;
  111         struct secasvar *sav;
  112         u_int32_t spi;
  113         int error;
  114 
  115         IPSEC_ISTAT(sproto, espstat.esps_input, ahstat.ahs_input,
  116                 ipcompstat.ipcomps_input);
  117 
  118         IPSEC_ASSERT(m != NULL, ("null packet"));
  119 
  120         IPSEC_ASSERT(sproto == IPPROTO_ESP || sproto == IPPROTO_AH ||
  121                 sproto == IPPROTO_IPCOMP,
  122                 ("unexpected security protocol %u", sproto));
  123 
  124         if ((sproto == IPPROTO_ESP && !esp_enable) ||
  125             (sproto == IPPROTO_AH && !ah_enable) ||
  126             (sproto == IPPROTO_IPCOMP && !ipcomp_enable)) {
  127                 m_freem(m);
  128                 IPSEC_ISTAT(sproto, espstat.esps_pdrops, ahstat.ahs_pdrops,
  129                     ipcompstat.ipcomps_pdrops);
  130                 return EOPNOTSUPP;
  131         }
  132 
  133         if (m->m_pkthdr.len - skip < 2 * sizeof (u_int32_t)) {
  134                 m_freem(m);
  135                 IPSEC_ISTAT(sproto, espstat.esps_hdrops, ahstat.ahs_hdrops,
  136                     ipcompstat.ipcomps_hdrops);
  137                 DPRINTF(("%s: packet too small\n", __func__));
  138                 return EINVAL;
  139         }
  140 
  141         /* Retrieve the SPI from the relevant IPsec header */
  142         if (sproto == IPPROTO_ESP)
  143                 m_copydata(m, skip, sizeof(u_int32_t), (caddr_t) &spi);
  144         else if (sproto == IPPROTO_AH)
  145                 m_copydata(m, skip + sizeof(u_int32_t), sizeof(u_int32_t),
  146                     (caddr_t) &spi);
  147         else if (sproto == IPPROTO_IPCOMP) {
  148                 u_int16_t cpi;
  149                 m_copydata(m, skip + sizeof(u_int16_t), sizeof(u_int16_t),
  150                     (caddr_t) &cpi);
  151                 spi = ntohl(htons(cpi));
  152         }
  153 
  154         /*
  155          * Find the SA and (indirectly) call the appropriate
  156          * kernel crypto routine. The resulting mbuf chain is a valid
  157          * IP packet ready to go through input processing.
  158          */
  159         bzero(&dst_address, sizeof (dst_address));
  160         dst_address.sa.sa_family = af;
  161         switch (af) {
  162 #ifdef INET
  163         case AF_INET:
  164                 dst_address.sin.sin_len = sizeof(struct sockaddr_in);
  165                 m_copydata(m, offsetof(struct ip, ip_dst),
  166                     sizeof(struct in_addr),
  167                     (caddr_t) &dst_address.sin.sin_addr);
  168                 break;
  169 #endif /* INET */
  170 #ifdef INET6
  171         case AF_INET6:
  172                 dst_address.sin6.sin6_len = sizeof(struct sockaddr_in6);
  173                 m_copydata(m, offsetof(struct ip6_hdr, ip6_dst),
  174                     sizeof(struct in6_addr),
  175                     (caddr_t) &dst_address.sin6.sin6_addr);
  176                 break;
  177 #endif /* INET6 */
  178         default:
  179                 DPRINTF(("%s: unsupported protocol family %u\n", __func__, af));
  180                 m_freem(m);
  181                 IPSEC_ISTAT(sproto, espstat.esps_nopf, ahstat.ahs_nopf,
  182                     ipcompstat.ipcomps_nopf);
  183                 return EPFNOSUPPORT;
  184         }
  185 
  186         /* NB: only pass dst since key_allocsa follows RFC2401 */
  187         sav = KEY_ALLOCSA(&dst_address, sproto, spi);
  188         if (sav == NULL) {
  189                 DPRINTF(("%s: no key association found for SA %s/%08lx/%u\n",
  190                           __func__, ipsec_address(&dst_address),
  191                           (u_long) ntohl(spi), sproto));
  192                 IPSEC_ISTAT(sproto, espstat.esps_notdb, ahstat.ahs_notdb,
  193                     ipcompstat.ipcomps_notdb);
  194                 m_freem(m);
  195                 return ENOENT;
  196         }
  197 
  198         if (sav->tdb_xform == NULL) {
  199                 DPRINTF(("%s: attempted to use uninitialized SA %s/%08lx/%u\n",
  200                          __func__, ipsec_address(&dst_address),
  201                          (u_long) ntohl(spi), sproto));
  202                 IPSEC_ISTAT(sproto, espstat.esps_noxform, ahstat.ahs_noxform,
  203                     ipcompstat.ipcomps_noxform);
  204                 KEY_FREESAV(&sav);
  205                 m_freem(m);
  206                 return ENXIO;
  207         }
  208 
  209         /*
  210          * Call appropriate transform and return -- callback takes care of
  211          * everything else.
  212          */
  213         error = (*sav->tdb_xform->xf_input)(m, sav, skip, protoff);
  214         KEY_FREESAV(&sav);
  215         return error;
  216 }
  217 
  218 #ifdef INET
  219 /*
  220  * Common input handler for IPv4 AH, ESP, and IPCOMP.
  221  */
  222 int
  223 ipsec4_common_input(struct mbuf *m, ...)
  224 {
  225         va_list ap;
  226         int off, nxt;
  227 
  228         va_start(ap, m);
  229         off = va_arg(ap, int);
  230         nxt = va_arg(ap, int);
  231         va_end(ap);
  232 
  233         return ipsec_common_input(m, off, offsetof(struct ip, ip_p),
  234                                   AF_INET, nxt);
  235 }
  236 
  237 void
  238 ah4_input(struct mbuf *m, int off)
  239 {
  240         ipsec4_common_input(m, off, IPPROTO_AH);
  241 }
  242 void
  243 ah4_ctlinput(int cmd, struct sockaddr *sa, void *v)
  244 {
  245         if (sa->sa_family == AF_INET &&
  246             sa->sa_len == sizeof(struct sockaddr_in))
  247                 ipsec4_common_ctlinput(cmd, sa, v, IPPROTO_AH);
  248 }
  249 
  250 void
  251 esp4_input(struct mbuf *m, int off)
  252 {
  253         ipsec4_common_input(m, off, IPPROTO_ESP);
  254 }
  255 void
  256 esp4_ctlinput(int cmd, struct sockaddr *sa, void *v)
  257 {
  258         if (sa->sa_family == AF_INET &&
  259             sa->sa_len == sizeof(struct sockaddr_in))
  260                 ipsec4_common_ctlinput(cmd, sa, v, IPPROTO_ESP);
  261 }
  262 
  263 void
  264 ipcomp4_input(struct mbuf *m, int off)
  265 {
  266         ipsec4_common_input(m, off, IPPROTO_IPCOMP);
  267 }
  268 
  269 /*
  270  * IPsec input callback for INET protocols.
  271  * This routine is called as the transform callback.
  272  * Takes care of filtering and other sanity checks on
  273  * the processed packet.
  274  */
  275 int
  276 ipsec4_common_input_cb(struct mbuf *m, struct secasvar *sav,
  277                         int skip, int protoff, struct m_tag *mt)
  278 {
  279         int prot, af, sproto;
  280         struct ip *ip;
  281         struct m_tag *mtag;
  282         struct tdb_ident *tdbi;
  283         struct secasindex *saidx;
  284         int error;
  285 
  286         IPSEC_SPLASSERT_SOFTNET(__func__);
  287 
  288         IPSEC_ASSERT(m != NULL, ("null mbuf"));
  289         IPSEC_ASSERT(sav != NULL, ("null SA"));
  290         IPSEC_ASSERT(sav->sah != NULL, ("null SAH"));
  291         saidx = &sav->sah->saidx;
  292         af = saidx->dst.sa.sa_family;
  293         IPSEC_ASSERT(af == AF_INET, ("unexpected af %u", af));
  294         sproto = saidx->proto;
  295         IPSEC_ASSERT(sproto == IPPROTO_ESP || sproto == IPPROTO_AH ||
  296                 sproto == IPPROTO_IPCOMP,
  297                 ("unexpected security protocol %u", sproto));
  298 
  299         /* Sanity check */
  300         if (m == NULL) {
  301                 DPRINTF(("%s: null mbuf", __func__));
  302                 IPSEC_ISTAT(sproto, espstat.esps_badkcr, ahstat.ahs_badkcr,
  303                     ipcompstat.ipcomps_badkcr);
  304                 KEY_FREESAV(&sav);
  305                 return EINVAL;
  306         }
  307 
  308         if (skip != 0) {
  309                 /* Fix IPv4 header */
  310                 if (m->m_len < skip && (m = m_pullup(m, skip)) == NULL) {
  311                         DPRINTF(("%s: processing failed for SA %s/%08lx\n",
  312                             __func__, ipsec_address(&sav->sah->saidx.dst),
  313                             (u_long) ntohl(sav->spi)));
  314                         IPSEC_ISTAT(sproto, espstat.esps_hdrops, ahstat.ahs_hdrops,
  315                             ipcompstat.ipcomps_hdrops);
  316                         error = ENOBUFS;
  317                         goto bad;
  318                 }
  319 
  320                 ip = mtod(m, struct ip *);
  321                 ip->ip_len = htons(m->m_pkthdr.len);
  322                 ip->ip_off = htons(ip->ip_off);
  323                 ip->ip_sum = 0;
  324                 ip->ip_sum = in_cksum(m, ip->ip_hl << 2);
  325         } else {
  326                 ip = mtod(m, struct ip *);
  327         }
  328         prot = ip->ip_p;
  329 
  330 #ifdef notyet
  331         /* IP-in-IP encapsulation */
  332         if (prot == IPPROTO_IPIP) {
  333                 struct ip ipn;
  334 
  335                 if (m->m_pkthdr.len - skip < sizeof(struct ip)) {
  336                         IPSEC_ISTAT(sproto, espstat.esps_hdrops,
  337                             ahstat.ahs_hdrops,
  338                             ipcompstat.ipcomps_hdrops);
  339                         error = EINVAL;
  340                         goto bad;
  341                 }
  342                 /* ipn will now contain the inner IPv4 header */
  343                 m_copydata(m, ip->ip_hl << 2, sizeof(struct ip),
  344                     (caddr_t) &ipn);
  345 
  346                 /* XXX PROXY address isn't recorded in SAH */
  347                 /*
  348                  * Check that the inner source address is the same as
  349                  * the proxy address, if available.
  350                  */
  351                 if ((saidx->proxy.sa.sa_family == AF_INET &&
  352                     saidx->proxy.sin.sin_addr.s_addr !=
  353                     INADDR_ANY &&
  354                     ipn.ip_src.s_addr !=
  355                     saidx->proxy.sin.sin_addr.s_addr) ||
  356                     (saidx->proxy.sa.sa_family != AF_INET &&
  357                         saidx->proxy.sa.sa_family != 0)) {
  358 
  359                         DPRINTF(("%s: inner source address %s doesn't "
  360                             "correspond to expected proxy source %s, "
  361                             "SA %s/%08lx\n", __func__,
  362                             inet_ntoa4(ipn.ip_src),
  363                             ipsp_address(saidx->proxy),
  364                             ipsp_address(saidx->dst),
  365                             (u_long) ntohl(sav->spi)));
  366 
  367                         IPSEC_ISTAT(sproto, espstat.esps_pdrops,
  368                             ahstat.ahs_pdrops,
  369                             ipcompstat.ipcomps_pdrops);
  370                         error = EACCES;
  371                         goto bad;
  372                 }
  373         }
  374 #ifdef INET6
  375         /* IPv6-in-IP encapsulation. */
  376         if (prot == IPPROTO_IPV6) {
  377                 struct ip6_hdr ip6n;
  378 
  379                 if (m->m_pkthdr.len - skip < sizeof(struct ip6_hdr)) {
  380                         IPSEC_ISTAT(sproto, espstat.esps_hdrops,
  381                             ahstat.ahs_hdrops,
  382                             ipcompstat.ipcomps_hdrops);
  383                         error = EINVAL;
  384                         goto bad;
  385                 }
  386                 /* ip6n will now contain the inner IPv6 header. */
  387                 m_copydata(m, ip->ip_hl << 2, sizeof(struct ip6_hdr),
  388                     (caddr_t) &ip6n);
  389 
  390                 /*
  391                  * Check that the inner source address is the same as
  392                  * the proxy address, if available.
  393                  */
  394                 if ((saidx->proxy.sa.sa_family == AF_INET6 &&
  395                     !IN6_IS_ADDR_UNSPECIFIED(&saidx->proxy.sin6.sin6_addr) &&
  396                     !IN6_ARE_ADDR_EQUAL(&ip6n.ip6_src,
  397                         &saidx->proxy.sin6.sin6_addr)) ||
  398                     (saidx->proxy.sa.sa_family != AF_INET6 &&
  399                         saidx->proxy.sa.sa_family != 0)) {
  400 
  401                         DPRINTF(("%s: inner source address %s doesn't "
  402                             "correspond to expected proxy source %s, "
  403                             "SA %s/%08lx\n", __func__,
  404                             ip6_sprintf(&ip6n.ip6_src),
  405                             ipsec_address(&saidx->proxy),
  406                             ipsec_address(&saidx->dst),
  407                             (u_long) ntohl(sav->spi)));
  408 
  409                         IPSEC_ISTAT(sproto, espstat.esps_pdrops,
  410                             ahstat.ahs_pdrops,
  411                             ipcompstat.ipcomps_pdrops);
  412                         error = EACCES;
  413                         goto bad;
  414                 }
  415         }
  416 #endif /* INET6 */
  417 #endif /*XXX*/
  418 
  419         /*
  420          * Record what we've done to the packet (under what SA it was
  421          * processed). If we've been passed an mtag, it means the packet
  422          * was already processed by an ethernet/crypto combo card and
  423          * thus has a tag attached with all the right information, but
  424          * with a PACKET_TAG_IPSEC_IN_CRYPTO_DONE as opposed to
  425          * PACKET_TAG_IPSEC_IN_DONE type; in that case, just change the type.
  426          */
  427         if (mt == NULL && sproto != IPPROTO_IPCOMP) {
  428                 mtag = m_tag_get(PACKET_TAG_IPSEC_IN_DONE,
  429                     sizeof(struct tdb_ident), M_NOWAIT);
  430                 if (mtag == NULL) {
  431                         DPRINTF(("%s: failed to get tag\n", __func__));
  432                         IPSEC_ISTAT(sproto, espstat.esps_hdrops,
  433                             ahstat.ahs_hdrops, ipcompstat.ipcomps_hdrops);
  434                         error = ENOMEM;
  435                         goto bad;
  436                 }
  437 
  438                 tdbi = (struct tdb_ident *)(mtag + 1);
  439                 bcopy(&saidx->dst, &tdbi->dst, saidx->dst.sa.sa_len);
  440                 tdbi->proto = sproto;
  441                 tdbi->spi = sav->spi;
  442 
  443                 m_tag_prepend(m, mtag);
  444         } else if (mt != NULL) {
  445                 mt->m_tag_id = PACKET_TAG_IPSEC_IN_DONE;
  446                 /* XXX do we need to mark m_flags??? */
  447         }
  448 
  449         key_sa_recordxfer(sav, m);              /* record data transfer */
  450 
  451 #ifdef DEV_ENC
  452         /*
  453          * Pass the mbuf to enc0 for bpf and pfil. We will filter the IPIP
  454          * packet later after it has been decapsulated.
  455          */
  456         ipsec_bpf(m, sav, AF_INET);
  457 
  458         if (prot != IPPROTO_IPIP)
  459                 if ((error = ipsec_filter(&m, PFIL_IN)) != 0)
  460                         return (error);
  461 #endif
  462 
  463         /*
  464          * Re-dispatch via software interrupt.
  465          */
  466         if ((error = netisr_queue(NETISR_IP, m))) {
  467                 IPSEC_ISTAT(sproto, espstat.esps_qfull, ahstat.ahs_qfull,
  468                             ipcompstat.ipcomps_qfull);
  469 
  470                 DPRINTF(("%s: queue full; proto %u packet dropped\n",
  471                         __func__, sproto));
  472                 return error;
  473         }
  474         return 0;
  475 bad:
  476         m_freem(m);
  477         return error;
  478 }
  479 
  480 void
  481 ipsec4_common_ctlinput(int cmd, struct sockaddr *sa, void *v, int proto)
  482 {
  483         /* XXX nothing just yet */
  484 }
  485 #endif /* INET */
  486 
  487 #ifdef INET6
  488 /* IPv6 AH wrapper. */
  489 int
  490 ipsec6_common_input(struct mbuf **mp, int *offp, int proto)
  491 {
  492         int l = 0;
  493         int protoff;
  494         struct ip6_ext ip6e;
  495 
  496         if (*offp < sizeof(struct ip6_hdr)) {
  497                 DPRINTF(("%s: bad offset %u\n", __func__, *offp));
  498                 return IPPROTO_DONE;
  499         } else if (*offp == sizeof(struct ip6_hdr)) {
  500                 protoff = offsetof(struct ip6_hdr, ip6_nxt);
  501         } else {
  502                 /* Chase down the header chain... */
  503                 protoff = sizeof(struct ip6_hdr);
  504 
  505                 do {
  506                         protoff += l;
  507                         m_copydata(*mp, protoff, sizeof(ip6e),
  508                             (caddr_t) &ip6e);
  509 
  510                         if (ip6e.ip6e_nxt == IPPROTO_AH)
  511                                 l = (ip6e.ip6e_len + 2) << 2;
  512                         else
  513                                 l = (ip6e.ip6e_len + 1) << 3;
  514                         IPSEC_ASSERT(l > 0, ("l went zero or negative"));
  515                 } while (protoff + l < *offp);
  516 
  517                 /* Malformed packet check */
  518                 if (protoff + l != *offp) {
  519                         DPRINTF(("%s: bad packet header chain, protoff %u, "
  520                                 "l %u, off %u\n", __func__, protoff, l, *offp));
  521                         IPSEC_ISTAT(proto, espstat.esps_hdrops,
  522                                     ahstat.ahs_hdrops,
  523                                     ipcompstat.ipcomps_hdrops);
  524                         m_freem(*mp);
  525                         *mp = NULL;
  526                         return IPPROTO_DONE;
  527                 }
  528                 protoff += offsetof(struct ip6_ext, ip6e_nxt);
  529         }
  530         (void) ipsec_common_input(*mp, *offp, protoff, AF_INET6, proto);
  531         return IPPROTO_DONE;
  532 }
  533 
  534 /*
  535  * IPsec input callback, called by the transform callback. Takes care of
  536  * filtering and other sanity checks on the processed packet.
  537  */
  538 int
  539 ipsec6_common_input_cb(struct mbuf *m, struct secasvar *sav, int skip, int protoff,
  540     struct m_tag *mt)
  541 {
  542         int prot, af, sproto;
  543         struct ip6_hdr *ip6;
  544         struct m_tag *mtag;
  545         struct tdb_ident *tdbi;
  546         struct secasindex *saidx;
  547         int nxt;
  548         u_int8_t nxt8;
  549         int error, nest;
  550 
  551         IPSEC_ASSERT(m != NULL, ("null mbuf"));
  552         IPSEC_ASSERT(sav != NULL, ("null SA"));
  553         IPSEC_ASSERT(sav->sah != NULL, ("null SAH"));
  554         saidx = &sav->sah->saidx;
  555         af = saidx->dst.sa.sa_family;
  556         IPSEC_ASSERT(af == AF_INET6, ("unexpected af %u", af));
  557         sproto = saidx->proto;
  558         IPSEC_ASSERT(sproto == IPPROTO_ESP || sproto == IPPROTO_AH ||
  559                 sproto == IPPROTO_IPCOMP,
  560                 ("unexpected security protocol %u", sproto));
  561 
  562         /* Sanity check */
  563         if (m == NULL) {
  564                 DPRINTF(("%s: null mbuf", __func__));
  565                 IPSEC_ISTAT(sproto, espstat.esps_badkcr, ahstat.ahs_badkcr,
  566                     ipcompstat.ipcomps_badkcr);
  567                 error = EINVAL;
  568                 goto bad;
  569         }
  570 
  571         /* Fix IPv6 header */
  572         if (m->m_len < sizeof(struct ip6_hdr) &&
  573             (m = m_pullup(m, sizeof(struct ip6_hdr))) == NULL) {
  574 
  575                 DPRINTF(("%s: processing failed for SA %s/%08lx\n",
  576                     __func__, ipsec_address(&sav->sah->saidx.dst),
  577                     (u_long) ntohl(sav->spi)));
  578 
  579                 IPSEC_ISTAT(sproto, espstat.esps_hdrops, ahstat.ahs_hdrops,
  580                     ipcompstat.ipcomps_hdrops);
  581                 error = EACCES;
  582                 goto bad;
  583         }
  584 
  585         ip6 = mtod(m, struct ip6_hdr *);
  586         ip6->ip6_plen = htons(m->m_pkthdr.len - sizeof(struct ip6_hdr));
  587 
  588         /* Save protocol */
  589         m_copydata(m, protoff, 1, (unsigned char *) &prot);
  590 
  591 #ifdef notyet
  592 #ifdef INET
  593         /* IP-in-IP encapsulation */
  594         if (prot == IPPROTO_IPIP) {
  595                 struct ip ipn;
  596 
  597                 if (m->m_pkthdr.len - skip < sizeof(struct ip)) {
  598                         IPSEC_ISTAT(sproto, espstat.esps_hdrops,
  599                             ahstat.ahs_hdrops,
  600                             ipcompstat.ipcomps_hdrops);
  601                         error = EINVAL;
  602                         goto bad;
  603                 }
  604                 /* ipn will now contain the inner IPv4 header */
  605                 m_copydata(m, skip, sizeof(struct ip), (caddr_t) &ipn);
  606 
  607                 /*
  608                  * Check that the inner source address is the same as
  609                  * the proxy address, if available.
  610                  */
  611                 if ((saidx->proxy.sa.sa_family == AF_INET &&
  612                     saidx->proxy.sin.sin_addr.s_addr != INADDR_ANY &&
  613                     ipn.ip_src.s_addr != saidx->proxy.sin.sin_addr.s_addr) ||
  614                     (saidx->proxy.sa.sa_family != AF_INET &&
  615                         saidx->proxy.sa.sa_family != 0)) {
  616 
  617                         DPRINTF(("%s: inner source address %s doesn't "
  618                             "correspond to expected proxy source %s, "
  619                             "SA %s/%08lx\n", __func__,
  620                             inet_ntoa4(ipn.ip_src),
  621                             ipsec_address(&saidx->proxy),
  622                             ipsec_address(&saidx->dst),
  623                             (u_long) ntohl(sav->spi)));
  624 
  625                         IPSEC_ISTATsproto, (espstat.esps_pdrops,
  626                             ahstat.ahs_pdrops, ipcompstat.ipcomps_pdrops);
  627                         error = EACCES;
  628                         goto bad;
  629                 }
  630         }
  631 #endif /* INET */
  632 
  633         /* IPv6-in-IP encapsulation */
  634         if (prot == IPPROTO_IPV6) {
  635                 struct ip6_hdr ip6n;
  636 
  637                 if (m->m_pkthdr.len - skip < sizeof(struct ip6_hdr)) {
  638                         IPSEC_ISTAT(sproto, espstat.esps_hdrops,
  639                             ahstat.ahs_hdrops,
  640                             ipcompstat.ipcomps_hdrops);
  641                         error = EINVAL;
  642                         goto bad;
  643                 }
  644                 /* ip6n will now contain the inner IPv6 header. */
  645                 m_copydata(m, skip, sizeof(struct ip6_hdr),
  646                     (caddr_t) &ip6n);
  647 
  648                 /*
  649                  * Check that the inner source address is the same as
  650                  * the proxy address, if available.
  651                  */
  652                 if ((saidx->proxy.sa.sa_family == AF_INET6 &&
  653                     !IN6_IS_ADDR_UNSPECIFIED(&saidx->proxy.sin6.sin6_addr) &&
  654                     !IN6_ARE_ADDR_EQUAL(&ip6n.ip6_src,
  655                         &saidx->proxy.sin6.sin6_addr)) ||
  656                     (saidx->proxy.sa.sa_family != AF_INET6 &&
  657                         saidx->proxy.sa.sa_family != 0)) {
  658 
  659                         DPRINTF(("%s: inner source address %s doesn't "
  660                             "correspond to expected proxy source %s, "
  661                             "SA %s/%08lx\n", __func__,
  662                             ip6_sprintf(&ip6n.ip6_src),
  663                             ipsec_address(&saidx->proxy),
  664                             ipsec_address(&saidx->dst),
  665                             (u_long) ntohl(sav->spi)));
  666 
  667                         IPSEC_ISTAT(sproto, espstat.esps_pdrops,
  668                             ahstat.ahs_pdrops, ipcompstat.ipcomps_pdrops);
  669                         error = EACCES;
  670                         goto bad;
  671                 }
  672         }
  673 #endif /*XXX*/
  674 
  675         /*
  676          * Record what we've done to the packet (under what SA it was
  677          * processed). If we've been passed an mtag, it means the packet
  678          * was already processed by an ethernet/crypto combo card and
  679          * thus has a tag attached with all the right information, but
  680          * with a PACKET_TAG_IPSEC_IN_CRYPTO_DONE as opposed to
  681          * PACKET_TAG_IPSEC_IN_DONE type; in that case, just change the type.
  682          */
  683         if (mt == NULL && sproto != IPPROTO_IPCOMP) {
  684                 mtag = m_tag_get(PACKET_TAG_IPSEC_IN_DONE,
  685                     sizeof(struct tdb_ident), M_NOWAIT);
  686                 if (mtag == NULL) {
  687                         DPRINTF(("%s: failed to get tag\n", __func__));
  688                         IPSEC_ISTAT(sproto, espstat.esps_hdrops,
  689                             ahstat.ahs_hdrops, ipcompstat.ipcomps_hdrops);
  690                         error = ENOMEM;
  691                         goto bad;
  692                 }
  693 
  694                 tdbi = (struct tdb_ident *)(mtag + 1);
  695                 bcopy(&saidx->dst, &tdbi->dst, sizeof(union sockaddr_union));
  696                 tdbi->proto = sproto;
  697                 tdbi->spi = sav->spi;
  698 
  699                 m_tag_prepend(m, mtag);
  700         } else {
  701                 if (mt != NULL)
  702                         mt->m_tag_id = PACKET_TAG_IPSEC_IN_DONE;
  703                 /* XXX do we need to mark m_flags??? */
  704         }
  705 
  706         key_sa_recordxfer(sav, m);
  707 
  708         /* Retrieve new protocol */
  709         m_copydata(m, protoff, sizeof(u_int8_t), (caddr_t) &nxt8);
  710 
  711         /*
  712          * See the end of ip6_input for this logic.
  713          * IPPROTO_IPV[46] case will be processed just like other ones
  714          */
  715         nest = 0;
  716         nxt = nxt8;
  717         while (nxt != IPPROTO_DONE) {
  718                 if (ip6_hdrnestlimit && (++nest > ip6_hdrnestlimit)) {
  719                         ip6stat.ip6s_toomanyhdr++;
  720                         error = EINVAL;
  721                         goto bad;
  722                 }
  723 
  724                 /*
  725                  * Protection against faulty packet - there should be
  726                  * more sanity checks in header chain processing.
  727                  */
  728                 if (m->m_pkthdr.len < skip) {
  729                         ip6stat.ip6s_tooshort++;
  730                         in6_ifstat_inc(m->m_pkthdr.rcvif, ifs6_in_truncated);
  731                         error = EINVAL;
  732                         goto bad;
  733                 }
  734                 /*
  735                  * Enforce IPsec policy checking if we are seeing last header.
  736                  * note that we do not visit this with protocols with pcb layer
  737                  * code - like udp/tcp/raw ip.
  738                  */
  739                 if ((inet6sw[ip6_protox[nxt]].pr_flags & PR_LASTHDR) != 0 &&
  740                     ipsec6_in_reject(m, NULL)) {
  741                         error = EINVAL;
  742                         goto bad;
  743                 }
  744                 nxt = (*inet6sw[ip6_protox[nxt]].pr_input)(&m, &skip, nxt);
  745         }
  746         return 0;
  747 bad:
  748         if (m)
  749                 m_freem(m);
  750         return error;
  751 }
  752 
  753 void
  754 esp6_ctlinput(int cmd, struct sockaddr *sa, void *d)
  755 {
  756         if (sa->sa_family != AF_INET6 ||
  757             sa->sa_len != sizeof(struct sockaddr_in6))
  758                 return;
  759         if ((unsigned)cmd >= PRC_NCMDS)
  760                 return;
  761 
  762         /* if the parameter is from icmp6, decode it. */
  763         if (d !=  NULL) {
  764                 struct ip6ctlparam *ip6cp = (struct ip6ctlparam *)d;
  765                 struct mbuf *m = ip6cp->ip6c_m;
  766                 int off = ip6cp->ip6c_off;
  767 
  768                 struct ip6ctlparam ip6cp1;
  769 
  770                 /*
  771                  * Notify the error to all possible sockets via pfctlinput2.
  772                  * Since the upper layer information (such as protocol type,
  773                  * source and destination ports) is embedded in the encrypted
  774                  * data and might have been cut, we can't directly call
  775                  * an upper layer ctlinput function. However, the pcbnotify
  776                  * function will consider source and destination addresses
  777                  * as well as the flow info value, and may be able to find
  778                  * some PCB that should be notified.
  779                  * Although pfctlinput2 will call esp6_ctlinput(), there is
  780                  * no possibility of an infinite loop of function calls,
  781                  * because we don't pass the inner IPv6 header.
  782                  */
  783                 bzero(&ip6cp1, sizeof(ip6cp1));
  784                 ip6cp1.ip6c_src = ip6cp->ip6c_src;
  785                 pfctlinput2(cmd, sa, (void *)&ip6cp1);
  786 
  787                 /*
  788                  * Then go to special cases that need ESP header information.
  789                  * XXX: We assume that when ip6 is non NULL,
  790                  * M and OFF are valid.
  791                  */
  792 
  793                 if (cmd == PRC_MSGSIZE) {
  794                         struct secasvar *sav;
  795                         u_int32_t spi;
  796                         int valid;
  797 
  798                         /* check header length before using m_copydata */
  799                         if (m->m_pkthdr.len < off + sizeof (struct esp))
  800                                 return;
  801                         m_copydata(m, off + offsetof(struct esp, esp_spi),
  802                                 sizeof(u_int32_t), (caddr_t) &spi);
  803                         /*
  804                          * Check to see if we have a valid SA corresponding to
  805                          * the address in the ICMP message payload.
  806                          */
  807                         sav = KEY_ALLOCSA((union sockaddr_union *)sa,
  808                                         IPPROTO_ESP, spi);
  809                         valid = (sav != NULL);
  810                         if (sav)
  811                                 KEY_FREESAV(&sav);
  812 
  813                         /* XXX Further validation? */
  814 
  815                         /*
  816                          * Depending on whether the SA is "valid" and
  817                          * routing table size (mtudisc_{hi,lo}wat), we will:
  818                          * - recalcurate the new MTU and create the
  819                          *   corresponding routing entry, or
  820                          * - ignore the MTU change notification.
  821                          */
  822                         icmp6_mtudisc_update(ip6cp, valid);
  823                 }
  824         } else {
  825                 /* we normally notify any pcb here */
  826         }
  827 }
  828 #endif /* INET6 */
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FreeBSD/Linux Kernel Cross Reference sys/netipsec/ipsec_input.c

FreeBSD/Linux Kernel Cross Reference
sys/netipsec/ipsec_input.c
