The Design and Implementation of the FreeBSD Operating System, Second Edition
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FreeBSD/Linux Kernel Cross Reference
sys/netipsec/ipsec_input.c

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    1 /*      $FreeBSD$       */
    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 #ifdef INET6
  286 #ifdef notyet
  287         char ip6buf[INET6_ADDRSTRLEN];
  288 #endif
  289 #endif
  290 
  291         IPSEC_SPLASSERT_SOFTNET(__func__);
  292 
  293         IPSEC_ASSERT(m != NULL, ("null mbuf"));
  294         IPSEC_ASSERT(sav != NULL, ("null SA"));
  295         IPSEC_ASSERT(sav->sah != NULL, ("null SAH"));
  296         saidx = &sav->sah->saidx;
  297         af = saidx->dst.sa.sa_family;
  298         IPSEC_ASSERT(af == AF_INET, ("unexpected af %u", af));
  299         sproto = saidx->proto;
  300         IPSEC_ASSERT(sproto == IPPROTO_ESP || sproto == IPPROTO_AH ||
  301                 sproto == IPPROTO_IPCOMP,
  302                 ("unexpected security protocol %u", sproto));
  303 
  304         /* Sanity check */
  305         if (m == NULL) {
  306                 DPRINTF(("%s: null mbuf", __func__));
  307                 IPSEC_ISTAT(sproto, espstat.esps_badkcr, ahstat.ahs_badkcr,
  308                     ipcompstat.ipcomps_badkcr);
  309                 KEY_FREESAV(&sav);
  310                 return EINVAL;
  311         }
  312 
  313         if (skip != 0) {
  314                 /* Fix IPv4 header */
  315                 if (m->m_len < skip && (m = m_pullup(m, skip)) == NULL) {
  316                         DPRINTF(("%s: processing failed for SA %s/%08lx\n",
  317                             __func__, ipsec_address(&sav->sah->saidx.dst),
  318                             (u_long) ntohl(sav->spi)));
  319                         IPSEC_ISTAT(sproto, espstat.esps_hdrops, ahstat.ahs_hdrops,
  320                             ipcompstat.ipcomps_hdrops);
  321                         error = ENOBUFS;
  322                         goto bad;
  323                 }
  324 
  325                 ip = mtod(m, struct ip *);
  326                 ip->ip_len = htons(m->m_pkthdr.len);
  327                 ip->ip_off = htons(ip->ip_off);
  328                 ip->ip_sum = 0;
  329                 ip->ip_sum = in_cksum(m, ip->ip_hl << 2);
  330         } else {
  331                 ip = mtod(m, struct ip *);
  332         }
  333         prot = ip->ip_p;
  334 
  335 #ifdef notyet
  336         /* IP-in-IP encapsulation */
  337         if (prot == IPPROTO_IPIP) {
  338                 struct ip ipn;
  339 
  340                 if (m->m_pkthdr.len - skip < sizeof(struct ip)) {
  341                         IPSEC_ISTAT(sproto, espstat.esps_hdrops,
  342                             ahstat.ahs_hdrops,
  343                             ipcompstat.ipcomps_hdrops);
  344                         error = EINVAL;
  345                         goto bad;
  346                 }
  347                 /* ipn will now contain the inner IPv4 header */
  348                 m_copydata(m, ip->ip_hl << 2, sizeof(struct ip),
  349                     (caddr_t) &ipn);
  350 
  351                 /* XXX PROXY address isn't recorded in SAH */
  352                 /*
  353                  * Check that the inner source address is the same as
  354                  * the proxy address, if available.
  355                  */
  356                 if ((saidx->proxy.sa.sa_family == AF_INET &&
  357                     saidx->proxy.sin.sin_addr.s_addr !=
  358                     INADDR_ANY &&
  359                     ipn.ip_src.s_addr !=
  360                     saidx->proxy.sin.sin_addr.s_addr) ||
  361                     (saidx->proxy.sa.sa_family != AF_INET &&
  362                         saidx->proxy.sa.sa_family != 0)) {
  363 
  364                         DPRINTF(("%s: inner source address %s doesn't "
  365                             "correspond to expected proxy source %s, "
  366                             "SA %s/%08lx\n", __func__,
  367                             inet_ntoa4(ipn.ip_src),
  368                             ipsp_address(saidx->proxy),
  369                             ipsp_address(saidx->dst),
  370                             (u_long) ntohl(sav->spi)));
  371 
  372                         IPSEC_ISTAT(sproto, espstat.esps_pdrops,
  373                             ahstat.ahs_pdrops,
  374                             ipcompstat.ipcomps_pdrops);
  375                         error = EACCES;
  376                         goto bad;
  377                 }
  378         }
  379 #ifdef INET6
  380         /* IPv6-in-IP encapsulation. */
  381         if (prot == IPPROTO_IPV6) {
  382                 struct ip6_hdr ip6n;
  383 
  384                 if (m->m_pkthdr.len - skip < sizeof(struct ip6_hdr)) {
  385                         IPSEC_ISTAT(sproto, espstat.esps_hdrops,
  386                             ahstat.ahs_hdrops,
  387                             ipcompstat.ipcomps_hdrops);
  388                         error = EINVAL;
  389                         goto bad;
  390                 }
  391                 /* ip6n will now contain the inner IPv6 header. */
  392                 m_copydata(m, ip->ip_hl << 2, sizeof(struct ip6_hdr),
  393                     (caddr_t) &ip6n);
  394 
  395                 /*
  396                  * Check that the inner source address is the same as
  397                  * the proxy address, if available.
  398                  */
  399                 if ((saidx->proxy.sa.sa_family == AF_INET6 &&
  400                     !IN6_IS_ADDR_UNSPECIFIED(&saidx->proxy.sin6.sin6_addr) &&
  401                     !IN6_ARE_ADDR_EQUAL(&ip6n.ip6_src,
  402                         &saidx->proxy.sin6.sin6_addr)) ||
  403                     (saidx->proxy.sa.sa_family != AF_INET6 &&
  404                         saidx->proxy.sa.sa_family != 0)) {
  405 
  406                         DPRINTF(("%s: inner source address %s doesn't "
  407                             "correspond to expected proxy source %s, "
  408                             "SA %s/%08lx\n", __func__,
  409                             ip6_sprintf(ip6buf, &ip6n.ip6_src),
  410                             ipsec_address(&saidx->proxy),
  411                             ipsec_address(&saidx->dst),
  412                             (u_long) ntohl(sav->spi)));
  413 
  414                         IPSEC_ISTAT(sproto, espstat.esps_pdrops,
  415                             ahstat.ahs_pdrops,
  416                             ipcompstat.ipcomps_pdrops);
  417                         error = EACCES;
  418                         goto bad;
  419                 }
  420         }
  421 #endif /* INET6 */
  422 #endif /*XXX*/
  423 
  424         /*
  425          * Record what we've done to the packet (under what SA it was
  426          * processed). If we've been passed an mtag, it means the packet
  427          * was already processed by an ethernet/crypto combo card and
  428          * thus has a tag attached with all the right information, but
  429          * with a PACKET_TAG_IPSEC_IN_CRYPTO_DONE as opposed to
  430          * PACKET_TAG_IPSEC_IN_DONE type; in that case, just change the type.
  431          */
  432         if (mt == NULL && sproto != IPPROTO_IPCOMP) {
  433                 mtag = m_tag_get(PACKET_TAG_IPSEC_IN_DONE,
  434                     sizeof(struct tdb_ident), M_NOWAIT);
  435                 if (mtag == NULL) {
  436                         DPRINTF(("%s: failed to get tag\n", __func__));
  437                         IPSEC_ISTAT(sproto, espstat.esps_hdrops,
  438                             ahstat.ahs_hdrops, ipcompstat.ipcomps_hdrops);
  439                         error = ENOMEM;
  440                         goto bad;
  441                 }
  442 
  443                 tdbi = (struct tdb_ident *)(mtag + 1);
  444                 bcopy(&saidx->dst, &tdbi->dst, saidx->dst.sa.sa_len);
  445                 tdbi->proto = sproto;
  446                 tdbi->spi = sav->spi;
  447 
  448                 m_tag_prepend(m, mtag);
  449         } else if (mt != NULL) {
  450                 mt->m_tag_id = PACKET_TAG_IPSEC_IN_DONE;
  451                 /* XXX do we need to mark m_flags??? */
  452         }
  453 
  454         key_sa_recordxfer(sav, m);              /* record data transfer */
  455 
  456 #ifdef DEV_ENC
  457         /*
  458          * Pass the mbuf to enc0 for bpf and pfil. We will filter the IPIP
  459          * packet later after it has been decapsulated.
  460          */
  461         ipsec_bpf(m, sav, AF_INET);
  462 
  463         if (prot != IPPROTO_IPIP)
  464                 if ((error = ipsec_filter(&m, PFIL_IN)) != 0)
  465                         return (error);
  466 #endif
  467 
  468         /*
  469          * Re-dispatch via software interrupt.
  470          */
  471         if ((error = netisr_queue(NETISR_IP, m))) {
  472                 IPSEC_ISTAT(sproto, espstat.esps_qfull, ahstat.ahs_qfull,
  473                             ipcompstat.ipcomps_qfull);
  474 
  475                 DPRINTF(("%s: queue full; proto %u packet dropped\n",
  476                         __func__, sproto));
  477                 return error;
  478         }
  479         return 0;
  480 bad:
  481         m_freem(m);
  482         return error;
  483 }
  484 
  485 void
  486 ipsec4_common_ctlinput(int cmd, struct sockaddr *sa, void *v, int proto)
  487 {
  488         /* XXX nothing just yet */
  489 }
  490 #endif /* INET */
  491 
  492 #ifdef INET6
  493 /* IPv6 AH wrapper. */
  494 int
  495 ipsec6_common_input(struct mbuf **mp, int *offp, int proto)
  496 {
  497         int l = 0;
  498         int protoff;
  499         struct ip6_ext ip6e;
  500 
  501         if (*offp < sizeof(struct ip6_hdr)) {
  502                 DPRINTF(("%s: bad offset %u\n", __func__, *offp));
  503                 return IPPROTO_DONE;
  504         } else if (*offp == sizeof(struct ip6_hdr)) {
  505                 protoff = offsetof(struct ip6_hdr, ip6_nxt);
  506         } else {
  507                 /* Chase down the header chain... */
  508                 protoff = sizeof(struct ip6_hdr);
  509 
  510                 do {
  511                         protoff += l;
  512                         m_copydata(*mp, protoff, sizeof(ip6e),
  513                             (caddr_t) &ip6e);
  514 
  515                         if (ip6e.ip6e_nxt == IPPROTO_AH)
  516                                 l = (ip6e.ip6e_len + 2) << 2;
  517                         else
  518                                 l = (ip6e.ip6e_len + 1) << 3;
  519                         IPSEC_ASSERT(l > 0, ("l went zero or negative"));
  520                 } while (protoff + l < *offp);
  521 
  522                 /* Malformed packet check */
  523                 if (protoff + l != *offp) {
  524                         DPRINTF(("%s: bad packet header chain, protoff %u, "
  525                                 "l %u, off %u\n", __func__, protoff, l, *offp));
  526                         IPSEC_ISTAT(proto, espstat.esps_hdrops,
  527                                     ahstat.ahs_hdrops,
  528                                     ipcompstat.ipcomps_hdrops);
  529                         m_freem(*mp);
  530                         *mp = NULL;
  531                         return IPPROTO_DONE;
  532                 }
  533                 protoff += offsetof(struct ip6_ext, ip6e_nxt);
  534         }
  535         (void) ipsec_common_input(*mp, *offp, protoff, AF_INET6, proto);
  536         return IPPROTO_DONE;
  537 }
  538 
  539 /*
  540  * IPsec input callback, called by the transform callback. Takes care of
  541  * filtering and other sanity checks on the processed packet.
  542  */
  543 int
  544 ipsec6_common_input_cb(struct mbuf *m, struct secasvar *sav, int skip, int protoff,
  545     struct m_tag *mt)
  546 {
  547         int prot, af, sproto;
  548         struct ip6_hdr *ip6;
  549         struct m_tag *mtag;
  550         struct tdb_ident *tdbi;
  551         struct secasindex *saidx;
  552         int nxt;
  553         u_int8_t nxt8;
  554         int error, nest;
  555 #ifdef notyet
  556         char ip6buf[INET6_ADDRSTRLEN];
  557 #endif
  558 
  559         IPSEC_ASSERT(m != NULL, ("null mbuf"));
  560         IPSEC_ASSERT(sav != NULL, ("null SA"));
  561         IPSEC_ASSERT(sav->sah != NULL, ("null SAH"));
  562         saidx = &sav->sah->saidx;
  563         af = saidx->dst.sa.sa_family;
  564         IPSEC_ASSERT(af == AF_INET6, ("unexpected af %u", af));
  565         sproto = saidx->proto;
  566         IPSEC_ASSERT(sproto == IPPROTO_ESP || sproto == IPPROTO_AH ||
  567                 sproto == IPPROTO_IPCOMP,
  568                 ("unexpected security protocol %u", sproto));
  569 
  570         /* Sanity check */
  571         if (m == NULL) {
  572                 DPRINTF(("%s: null mbuf", __func__));
  573                 IPSEC_ISTAT(sproto, espstat.esps_badkcr, ahstat.ahs_badkcr,
  574                     ipcompstat.ipcomps_badkcr);
  575                 error = EINVAL;
  576                 goto bad;
  577         }
  578 
  579         /* Fix IPv6 header */
  580         if (m->m_len < sizeof(struct ip6_hdr) &&
  581             (m = m_pullup(m, sizeof(struct ip6_hdr))) == NULL) {
  582 
  583                 DPRINTF(("%s: processing failed for SA %s/%08lx\n",
  584                     __func__, ipsec_address(&sav->sah->saidx.dst),
  585                     (u_long) ntohl(sav->spi)));
  586 
  587                 IPSEC_ISTAT(sproto, espstat.esps_hdrops, ahstat.ahs_hdrops,
  588                     ipcompstat.ipcomps_hdrops);
  589                 error = EACCES;
  590                 goto bad;
  591         }
  592 
  593         ip6 = mtod(m, struct ip6_hdr *);
  594         ip6->ip6_plen = htons(m->m_pkthdr.len - sizeof(struct ip6_hdr));
  595 
  596         /* Save protocol */
  597         m_copydata(m, protoff, 1, (unsigned char *) &prot);
  598 
  599 #ifdef notyet
  600 #ifdef INET
  601         /* IP-in-IP encapsulation */
  602         if (prot == IPPROTO_IPIP) {
  603                 struct ip ipn;
  604 
  605                 if (m->m_pkthdr.len - skip < sizeof(struct ip)) {
  606                         IPSEC_ISTAT(sproto, espstat.esps_hdrops,
  607                             ahstat.ahs_hdrops,
  608                             ipcompstat.ipcomps_hdrops);
  609                         error = EINVAL;
  610                         goto bad;
  611                 }
  612                 /* ipn will now contain the inner IPv4 header */
  613                 m_copydata(m, skip, sizeof(struct ip), (caddr_t) &ipn);
  614 
  615                 /*
  616                  * Check that the inner source address is the same as
  617                  * the proxy address, if available.
  618                  */
  619                 if ((saidx->proxy.sa.sa_family == AF_INET &&
  620                     saidx->proxy.sin.sin_addr.s_addr != INADDR_ANY &&
  621                     ipn.ip_src.s_addr != saidx->proxy.sin.sin_addr.s_addr) ||
  622                     (saidx->proxy.sa.sa_family != AF_INET &&
  623                         saidx->proxy.sa.sa_family != 0)) {
  624 
  625                         DPRINTF(("%s: inner source address %s doesn't "
  626                             "correspond to expected proxy source %s, "
  627                             "SA %s/%08lx\n", __func__,
  628                             inet_ntoa4(ipn.ip_src),
  629                             ipsec_address(&saidx->proxy),
  630                             ipsec_address(&saidx->dst),
  631                             (u_long) ntohl(sav->spi)));
  632 
  633                         IPSEC_ISTATsproto, (espstat.esps_pdrops,
  634                             ahstat.ahs_pdrops, ipcompstat.ipcomps_pdrops);
  635                         error = EACCES;
  636                         goto bad;
  637                 }
  638         }
  639 #endif /* INET */
  640 
  641         /* IPv6-in-IP encapsulation */
  642         if (prot == IPPROTO_IPV6) {
  643                 struct ip6_hdr ip6n;
  644 
  645                 if (m->m_pkthdr.len - skip < sizeof(struct ip6_hdr)) {
  646                         IPSEC_ISTAT(sproto, espstat.esps_hdrops,
  647                             ahstat.ahs_hdrops,
  648                             ipcompstat.ipcomps_hdrops);
  649                         error = EINVAL;
  650                         goto bad;
  651                 }
  652                 /* ip6n will now contain the inner IPv6 header. */
  653                 m_copydata(m, skip, sizeof(struct ip6_hdr),
  654                     (caddr_t) &ip6n);
  655 
  656                 /*
  657                  * Check that the inner source address is the same as
  658                  * the proxy address, if available.
  659                  */
  660                 if ((saidx->proxy.sa.sa_family == AF_INET6 &&
  661                     !IN6_IS_ADDR_UNSPECIFIED(&saidx->proxy.sin6.sin6_addr) &&
  662                     !IN6_ARE_ADDR_EQUAL(&ip6n.ip6_src,
  663                         &saidx->proxy.sin6.sin6_addr)) ||
  664                     (saidx->proxy.sa.sa_family != AF_INET6 &&
  665                         saidx->proxy.sa.sa_family != 0)) {
  666 
  667                         DPRINTF(("%s: inner source address %s doesn't "
  668                             "correspond to expected proxy source %s, "
  669                             "SA %s/%08lx\n", __func__,
  670                             ip6_sprintf(ip6buf, &ip6n.ip6_src),
  671                             ipsec_address(&saidx->proxy),
  672                             ipsec_address(&saidx->dst),
  673                             (u_long) ntohl(sav->spi)));
  674 
  675                         IPSEC_ISTAT(sproto, espstat.esps_pdrops,
  676                             ahstat.ahs_pdrops, ipcompstat.ipcomps_pdrops);
  677                         error = EACCES;
  678                         goto bad;
  679                 }
  680         }
  681 #endif /*XXX*/
  682 
  683         /*
  684          * Record what we've done to the packet (under what SA it was
  685          * processed). If we've been passed an mtag, it means the packet
  686          * was already processed by an ethernet/crypto combo card and
  687          * thus has a tag attached with all the right information, but
  688          * with a PACKET_TAG_IPSEC_IN_CRYPTO_DONE as opposed to
  689          * PACKET_TAG_IPSEC_IN_DONE type; in that case, just change the type.
  690          */
  691         if (mt == NULL && sproto != IPPROTO_IPCOMP) {
  692                 mtag = m_tag_get(PACKET_TAG_IPSEC_IN_DONE,
  693                     sizeof(struct tdb_ident), M_NOWAIT);
  694                 if (mtag == NULL) {
  695                         DPRINTF(("%s: failed to get tag\n", __func__));
  696                         IPSEC_ISTAT(sproto, espstat.esps_hdrops,
  697                             ahstat.ahs_hdrops, ipcompstat.ipcomps_hdrops);
  698                         error = ENOMEM;
  699                         goto bad;
  700                 }
  701 
  702                 tdbi = (struct tdb_ident *)(mtag + 1);
  703                 bcopy(&saidx->dst, &tdbi->dst, sizeof(union sockaddr_union));
  704                 tdbi->proto = sproto;
  705                 tdbi->spi = sav->spi;
  706 
  707                 m_tag_prepend(m, mtag);
  708         } else {
  709                 if (mt != NULL)
  710                         mt->m_tag_id = PACKET_TAG_IPSEC_IN_DONE;
  711                 /* XXX do we need to mark m_flags??? */
  712         }
  713 
  714         key_sa_recordxfer(sav, m);
  715 
  716         /* Retrieve new protocol */
  717         m_copydata(m, protoff, sizeof(u_int8_t), (caddr_t) &nxt8);
  718 
  719         /*
  720          * See the end of ip6_input for this logic.
  721          * IPPROTO_IPV[46] case will be processed just like other ones
  722          */
  723         nest = 0;
  724         nxt = nxt8;
  725         while (nxt != IPPROTO_DONE) {
  726                 if (ip6_hdrnestlimit && (++nest > ip6_hdrnestlimit)) {
  727                         ip6stat.ip6s_toomanyhdr++;
  728                         error = EINVAL;
  729                         goto bad;
  730                 }
  731 
  732                 /*
  733                  * Protection against faulty packet - there should be
  734                  * more sanity checks in header chain processing.
  735                  */
  736                 if (m->m_pkthdr.len < skip) {
  737                         ip6stat.ip6s_tooshort++;
  738                         in6_ifstat_inc(m->m_pkthdr.rcvif, ifs6_in_truncated);
  739                         error = EINVAL;
  740                         goto bad;
  741                 }
  742                 /*
  743                  * Enforce IPsec policy checking if we are seeing last header.
  744                  * note that we do not visit this with protocols with pcb layer
  745                  * code - like udp/tcp/raw ip.
  746                  */
  747                 if ((inet6sw[ip6_protox[nxt]].pr_flags & PR_LASTHDR) != 0 &&
  748                     ipsec6_in_reject(m, NULL)) {
  749                         error = EINVAL;
  750                         goto bad;
  751                 }
  752                 nxt = (*inet6sw[ip6_protox[nxt]].pr_input)(&m, &skip, nxt);
  753         }
  754         return 0;
  755 bad:
  756         if (m)
  757                 m_freem(m);
  758         return error;
  759 }
  760 
  761 void
  762 esp6_ctlinput(int cmd, struct sockaddr *sa, void *d)
  763 {
  764         struct ip6ctlparam *ip6cp = NULL;
  765         struct mbuf *m = NULL;
  766         struct ip6_hdr *ip6;
  767         int off;
  768 
  769         if (sa->sa_family != AF_INET6 ||
  770             sa->sa_len != sizeof(struct sockaddr_in6))
  771                 return;
  772         if ((unsigned)cmd >= PRC_NCMDS)
  773                 return;
  774 
  775         /* if the parameter is from icmp6, decode it. */
  776         if (d != NULL) {
  777                 ip6cp = (struct ip6ctlparam *)d;
  778                 m = ip6cp->ip6c_m;
  779                 ip6 = ip6cp->ip6c_ip6;
  780                 off = ip6cp->ip6c_off;
  781         } else {
  782                 m = NULL;
  783                 ip6 = NULL;
  784                 off = 0;        /* calm gcc */
  785         }
  786 
  787         if (ip6 != NULL) {
  788 
  789                 struct ip6ctlparam ip6cp1;
  790 
  791                 /*
  792                  * Notify the error to all possible sockets via pfctlinput2.
  793                  * Since the upper layer information (such as protocol type,
  794                  * source and destination ports) is embedded in the encrypted
  795                  * data and might have been cut, we can't directly call
  796                  * an upper layer ctlinput function. However, the pcbnotify
  797                  * function will consider source and destination addresses
  798                  * as well as the flow info value, and may be able to find
  799                  * some PCB that should be notified.
  800                  * Although pfctlinput2 will call esp6_ctlinput(), there is
  801                  * no possibility of an infinite loop of function calls,
  802                  * because we don't pass the inner IPv6 header.
  803                  */
  804                 bzero(&ip6cp1, sizeof(ip6cp1));
  805                 ip6cp1.ip6c_src = ip6cp->ip6c_src;
  806                 pfctlinput2(cmd, sa, (void *)&ip6cp1);
  807 
  808                 /*
  809                  * Then go to special cases that need ESP header information.
  810                  * XXX: We assume that when ip6 is non NULL,
  811                  * M and OFF are valid.
  812                  */
  813 
  814                 if (cmd == PRC_MSGSIZE) {
  815                         struct secasvar *sav;
  816                         u_int32_t spi;
  817                         int valid;
  818 
  819                         /* check header length before using m_copydata */
  820                         if (m->m_pkthdr.len < off + sizeof (struct esp))
  821                                 return;
  822                         m_copydata(m, off + offsetof(struct esp, esp_spi),
  823                                 sizeof(u_int32_t), (caddr_t) &spi);
  824                         /*
  825                          * Check to see if we have a valid SA corresponding to
  826                          * the address in the ICMP message payload.
  827                          */
  828                         sav = KEY_ALLOCSA((union sockaddr_union *)sa,
  829                                         IPPROTO_ESP, spi);
  830                         valid = (sav != NULL);
  831                         if (sav)
  832                                 KEY_FREESAV(&sav);
  833 
  834                         /* XXX Further validation? */
  835 
  836                         /*
  837                          * Depending on whether the SA is "valid" and
  838                          * routing table size (mtudisc_{hi,lo}wat), we will:
  839                          * - recalcurate the new MTU and create the
  840                          *   corresponding routing entry, or
  841                          * - ignore the MTU change notification.
  842                          */
  843                         icmp6_mtudisc_update(ip6cp, valid);
  844                 }
  845         } else {
  846                 /* we normally notify any pcb here */
  847         }
  848 }
  849 #endif /* INET6 */

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