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: releng/8.3/sys/netipsec/ipsec_input.c 209691 2010-07-04 12:22:17Z 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 #include <net/vnet.h>
   63 
   64 #include <netinet/in.h>
   65 #include <netinet/in_systm.h>
   66 #include <netinet/ip.h>
   67 #include <netinet/ip_var.h>
   68 #include <netinet/in_var.h>
   69 
   70 #include <netinet/ip6.h>
   71 #ifdef INET6
   72 #include <netinet6/ip6_var.h>
   73 #endif
   74 #include <netinet/in_pcb.h>
   75 #ifdef INET6
   76 #include <netinet/icmp6.h>
   77 #endif
   78 
   79 #include <netipsec/ipsec.h>
   80 #ifdef INET6
   81 #include <netipsec/ipsec6.h>
   82 #endif
   83 #include <netipsec/ah_var.h>
   84 #include <netipsec/esp.h>
   85 #include <netipsec/esp_var.h>
   86 #include <netipsec/ipcomp_var.h>
   87 
   88 #include <netipsec/key.h>
   89 #include <netipsec/keydb.h>
   90 
   91 #include <netipsec/xform.h>
   92 #include <netinet6/ip6protosw.h>
   93 
   94 #include <machine/in_cksum.h>
   95 #include <machine/stdarg.h>
   96 
   97 #ifdef DEV_ENC
   98 #include <net/if_enc.h>
   99 #endif
  100 
  101 
  102 #define IPSEC_ISTAT(p,x,y,z) ((p) == IPPROTO_ESP ? (x)++ : \
  103                             (p) == IPPROTO_AH ? (y)++ : (z)++)
  104 
  105 #ifdef INET
  106 static void ipsec4_common_ctlinput(int, struct sockaddr *, void *, int);
  107 #endif
  108 
  109 /*
  110  * ipsec_common_input gets called when an IPsec-protected packet
  111  * is received by IPv4 or IPv6.  It's job is to find the right SA
  112  * and call the appropriate transform.  The transform callback
  113  * takes care of further processing (like ingress filtering).
  114  */
  115 static int
  116 ipsec_common_input(struct mbuf *m, int skip, int protoff, int af, int sproto)
  117 {
  118         union sockaddr_union dst_address;
  119         struct secasvar *sav;
  120         u_int32_t spi;
  121         int error;
  122 #ifdef IPSEC_NAT_T
  123         struct m_tag *tag;
  124 #endif
  125 
  126         IPSEC_ISTAT(sproto, V_espstat.esps_input, V_ahstat.ahs_input,
  127                 V_ipcompstat.ipcomps_input);
  128 
  129         IPSEC_ASSERT(m != NULL, ("null packet"));
  130 
  131         IPSEC_ASSERT(sproto == IPPROTO_ESP || sproto == IPPROTO_AH ||
  132                 sproto == IPPROTO_IPCOMP,
  133                 ("unexpected security protocol %u", sproto));
  134 
  135         if ((sproto == IPPROTO_ESP && !V_esp_enable) ||
  136             (sproto == IPPROTO_AH && !V_ah_enable) ||
  137             (sproto == IPPROTO_IPCOMP && !V_ipcomp_enable)) {
  138                 m_freem(m);
  139                 IPSEC_ISTAT(sproto, V_espstat.esps_pdrops, V_ahstat.ahs_pdrops,
  140                     V_ipcompstat.ipcomps_pdrops);
  141                 return EOPNOTSUPP;
  142         }
  143 
  144         if (m->m_pkthdr.len - skip < 2 * sizeof (u_int32_t)) {
  145                 m_freem(m);
  146                 IPSEC_ISTAT(sproto, V_espstat.esps_hdrops, V_ahstat.ahs_hdrops,
  147                     V_ipcompstat.ipcomps_hdrops);
  148                 DPRINTF(("%s: packet too small\n", __func__));
  149                 return EINVAL;
  150         }
  151 
  152         /* Retrieve the SPI from the relevant IPsec header */
  153         if (sproto == IPPROTO_ESP)
  154                 m_copydata(m, skip, sizeof(u_int32_t), (caddr_t) &spi);
  155         else if (sproto == IPPROTO_AH)
  156                 m_copydata(m, skip + sizeof(u_int32_t), sizeof(u_int32_t),
  157                     (caddr_t) &spi);
  158         else if (sproto == IPPROTO_IPCOMP) {
  159                 u_int16_t cpi;
  160                 m_copydata(m, skip + sizeof(u_int16_t), sizeof(u_int16_t),
  161                     (caddr_t) &cpi);
  162                 spi = ntohl(htons(cpi));
  163         }
  164 
  165         /*
  166          * Find the SA and (indirectly) call the appropriate
  167          * kernel crypto routine. The resulting mbuf chain is a valid
  168          * IP packet ready to go through input processing.
  169          */
  170         bzero(&dst_address, sizeof (dst_address));
  171         dst_address.sa.sa_family = af;
  172         switch (af) {
  173 #ifdef INET
  174         case AF_INET:
  175                 dst_address.sin.sin_len = sizeof(struct sockaddr_in);
  176                 m_copydata(m, offsetof(struct ip, ip_dst),
  177                     sizeof(struct in_addr),
  178                     (caddr_t) &dst_address.sin.sin_addr);
  179 #ifdef IPSEC_NAT_T
  180                 /* Find the source port for NAT-T; see udp*_espdecap. */
  181                 tag = m_tag_find(m, PACKET_TAG_IPSEC_NAT_T_PORTS, NULL);
  182                 if (tag != NULL)
  183                         dst_address.sin.sin_port = ((u_int16_t *)(tag + 1))[1];
  184 #endif /* IPSEC_NAT_T */
  185                 break;
  186 #endif /* INET */
  187 #ifdef INET6
  188         case AF_INET6:
  189                 dst_address.sin6.sin6_len = sizeof(struct sockaddr_in6);
  190                 m_copydata(m, offsetof(struct ip6_hdr, ip6_dst),
  191                     sizeof(struct in6_addr),
  192                     (caddr_t) &dst_address.sin6.sin6_addr);
  193                 break;
  194 #endif /* INET6 */
  195         default:
  196                 DPRINTF(("%s: unsupported protocol family %u\n", __func__, af));
  197                 m_freem(m);
  198                 IPSEC_ISTAT(sproto, V_espstat.esps_nopf, V_ahstat.ahs_nopf,
  199                     V_ipcompstat.ipcomps_nopf);
  200                 return EPFNOSUPPORT;
  201         }
  202 
  203         /* NB: only pass dst since key_allocsa follows RFC2401 */
  204         sav = KEY_ALLOCSA(&dst_address, sproto, spi);
  205         if (sav == NULL) {
  206                 DPRINTF(("%s: no key association found for SA %s/%08lx/%u\n",
  207                           __func__, ipsec_address(&dst_address),
  208                           (u_long) ntohl(spi), sproto));
  209                 IPSEC_ISTAT(sproto, V_espstat.esps_notdb, V_ahstat.ahs_notdb,
  210                     V_ipcompstat.ipcomps_notdb);
  211                 m_freem(m);
  212                 return ENOENT;
  213         }
  214 
  215         if (sav->tdb_xform == NULL) {
  216                 DPRINTF(("%s: attempted to use uninitialized SA %s/%08lx/%u\n",
  217                          __func__, ipsec_address(&dst_address),
  218                          (u_long) ntohl(spi), sproto));
  219                 IPSEC_ISTAT(sproto, V_espstat.esps_noxform, V_ahstat.ahs_noxform,
  220                     V_ipcompstat.ipcomps_noxform);
  221                 KEY_FREESAV(&sav);
  222                 m_freem(m);
  223                 return ENXIO;
  224         }
  225 
  226         /*
  227          * Call appropriate transform and return -- callback takes care of
  228          * everything else.
  229          */
  230         error = (*sav->tdb_xform->xf_input)(m, sav, skip, protoff);
  231         KEY_FREESAV(&sav);
  232         return error;
  233 }
  234 
  235 #ifdef INET
  236 /*
  237  * Common input handler for IPv4 AH, ESP, and IPCOMP.
  238  */
  239 int
  240 ipsec4_common_input(struct mbuf *m, ...)
  241 {
  242         va_list ap;
  243         int off, nxt;
  244 
  245         va_start(ap, m);
  246         off = va_arg(ap, int);
  247         nxt = va_arg(ap, int);
  248         va_end(ap);
  249 
  250         return ipsec_common_input(m, off, offsetof(struct ip, ip_p),
  251                                   AF_INET, nxt);
  252 }
  253 
  254 void
  255 ah4_input(struct mbuf *m, int off)
  256 {
  257         ipsec4_common_input(m, off, IPPROTO_AH);
  258 }
  259 void
  260 ah4_ctlinput(int cmd, struct sockaddr *sa, void *v)
  261 {
  262         if (sa->sa_family == AF_INET &&
  263             sa->sa_len == sizeof(struct sockaddr_in))
  264                 ipsec4_common_ctlinput(cmd, sa, v, IPPROTO_AH);
  265 }
  266 
  267 void
  268 esp4_input(struct mbuf *m, int off)
  269 {
  270         ipsec4_common_input(m, off, IPPROTO_ESP);
  271 }
  272 void
  273 esp4_ctlinput(int cmd, struct sockaddr *sa, void *v)
  274 {
  275         if (sa->sa_family == AF_INET &&
  276             sa->sa_len == sizeof(struct sockaddr_in))
  277                 ipsec4_common_ctlinput(cmd, sa, v, IPPROTO_ESP);
  278 }
  279 
  280 void
  281 ipcomp4_input(struct mbuf *m, int off)
  282 {
  283         ipsec4_common_input(m, off, IPPROTO_IPCOMP);
  284 }
  285 
  286 /*
  287  * IPsec input callback for INET protocols.
  288  * This routine is called as the transform callback.
  289  * Takes care of filtering and other sanity checks on
  290  * the processed packet.
  291  */
  292 int
  293 ipsec4_common_input_cb(struct mbuf *m, struct secasvar *sav,
  294                         int skip, int protoff, struct m_tag *mt)
  295 {
  296         int prot, af, sproto;
  297         struct ip *ip;
  298         struct m_tag *mtag;
  299         struct tdb_ident *tdbi;
  300         struct secasindex *saidx;
  301         int error;
  302 #ifdef INET6
  303 #ifdef notyet
  304         char ip6buf[INET6_ADDRSTRLEN];
  305 #endif
  306 #endif
  307 
  308         IPSEC_ASSERT(m != NULL, ("null mbuf"));
  309         IPSEC_ASSERT(sav != NULL, ("null SA"));
  310         IPSEC_ASSERT(sav->sah != NULL, ("null SAH"));
  311         saidx = &sav->sah->saidx;
  312         af = saidx->dst.sa.sa_family;
  313         IPSEC_ASSERT(af == AF_INET, ("unexpected af %u", af));
  314         sproto = saidx->proto;
  315         IPSEC_ASSERT(sproto == IPPROTO_ESP || sproto == IPPROTO_AH ||
  316                 sproto == IPPROTO_IPCOMP,
  317                 ("unexpected security protocol %u", sproto));
  318 
  319         /* Sanity check */
  320         if (m == NULL) {
  321                 DPRINTF(("%s: null mbuf", __func__));
  322                 IPSEC_ISTAT(sproto, V_espstat.esps_badkcr, V_ahstat.ahs_badkcr,
  323                     V_ipcompstat.ipcomps_badkcr);
  324                 KEY_FREESAV(&sav);
  325                 return EINVAL;
  326         }
  327 
  328         if (skip != 0) {
  329                 /* Fix IPv4 header */
  330                 if (m->m_len < skip && (m = m_pullup(m, skip)) == NULL) {
  331                         DPRINTF(("%s: processing failed for SA %s/%08lx\n",
  332                             __func__, ipsec_address(&sav->sah->saidx.dst),
  333                             (u_long) ntohl(sav->spi)));
  334                         IPSEC_ISTAT(sproto, V_espstat.esps_hdrops, V_ahstat.ahs_hdrops,
  335                             V_ipcompstat.ipcomps_hdrops);
  336                         error = ENOBUFS;
  337                         goto bad;
  338                 }
  339 
  340                 ip = mtod(m, struct ip *);
  341                 ip->ip_len = htons(m->m_pkthdr.len);
  342                 ip->ip_off = htons(ip->ip_off);
  343                 ip->ip_sum = 0;
  344                 ip->ip_sum = in_cksum(m, ip->ip_hl << 2);
  345         } else {
  346                 ip = mtod(m, struct ip *);
  347         }
  348         prot = ip->ip_p;
  349 
  350 #ifdef notyet
  351         /* IP-in-IP encapsulation */
  352         if (prot == IPPROTO_IPIP) {
  353                 struct ip ipn;
  354 
  355                 if (m->m_pkthdr.len - skip < sizeof(struct ip)) {
  356                         IPSEC_ISTAT(sproto, V_espstat.esps_hdrops,
  357                             V_ahstat.ahs_hdrops,
  358                             V_ipcompstat.ipcomps_hdrops);
  359                         error = EINVAL;
  360                         goto bad;
  361                 }
  362                 /* ipn will now contain the inner IPv4 header */
  363                 m_copydata(m, ip->ip_hl << 2, sizeof(struct ip),
  364                     (caddr_t) &ipn);
  365 
  366                 /* XXX PROXY address isn't recorded in SAH */
  367                 /*
  368                  * Check that the inner source address is the same as
  369                  * the proxy address, if available.
  370                  */
  371                 if ((saidx->proxy.sa.sa_family == AF_INET &&
  372                     saidx->proxy.sin.sin_addr.s_addr !=
  373                     INADDR_ANY &&
  374                     ipn.ip_src.s_addr !=
  375                     saidx->proxy.sin.sin_addr.s_addr) ||
  376                     (saidx->proxy.sa.sa_family != AF_INET &&
  377                         saidx->proxy.sa.sa_family != 0)) {
  378 
  379                         DPRINTF(("%s: inner source address %s doesn't "
  380                             "correspond to expected proxy source %s, "
  381                             "SA %s/%08lx\n", __func__,
  382                             inet_ntoa4(ipn.ip_src),
  383                             ipsp_address(saidx->proxy),
  384                             ipsp_address(saidx->dst),
  385                             (u_long) ntohl(sav->spi)));
  386 
  387                         IPSEC_ISTAT(sproto, V_espstat.esps_pdrops,
  388                             V_ahstat.ahs_pdrops,
  389                             V_ipcompstat.ipcomps_pdrops);
  390                         error = EACCES;
  391                         goto bad;
  392                 }
  393         }
  394 #ifdef INET6
  395         /* IPv6-in-IP encapsulation. */
  396         if (prot == IPPROTO_IPV6) {
  397                 struct ip6_hdr ip6n;
  398 
  399                 if (m->m_pkthdr.len - skip < sizeof(struct ip6_hdr)) {
  400                         IPSEC_ISTAT(sproto, V_espstat.esps_hdrops,
  401                             V_ahstat.ahs_hdrops,
  402                             V_ipcompstat.ipcomps_hdrops);
  403                         error = EINVAL;
  404                         goto bad;
  405                 }
  406                 /* ip6n will now contain the inner IPv6 header. */
  407                 m_copydata(m, ip->ip_hl << 2, sizeof(struct ip6_hdr),
  408                     (caddr_t) &ip6n);
  409 
  410                 /*
  411                  * Check that the inner source address is the same as
  412                  * the proxy address, if available.
  413                  */
  414                 if ((saidx->proxy.sa.sa_family == AF_INET6 &&
  415                     !IN6_IS_ADDR_UNSPECIFIED(&saidx->proxy.sin6.sin6_addr) &&
  416                     !IN6_ARE_ADDR_EQUAL(&ip6n.ip6_src,
  417                         &saidx->proxy.sin6.sin6_addr)) ||
  418                     (saidx->proxy.sa.sa_family != AF_INET6 &&
  419                         saidx->proxy.sa.sa_family != 0)) {
  420 
  421                         DPRINTF(("%s: inner source address %s doesn't "
  422                             "correspond to expected proxy source %s, "
  423                             "SA %s/%08lx\n", __func__,
  424                             ip6_sprintf(ip6buf, &ip6n.ip6_src),
  425                             ipsec_address(&saidx->proxy),
  426                             ipsec_address(&saidx->dst),
  427                             (u_long) ntohl(sav->spi)));
  428 
  429                         IPSEC_ISTAT(sproto, V_espstat.esps_pdrops,
  430                             V_ahstat.ahs_pdrops,
  431                             V_ipcompstat.ipcomps_pdrops);
  432                         error = EACCES;
  433                         goto bad;
  434                 }
  435         }
  436 #endif /* INET6 */
  437 #endif /*XXX*/
  438 
  439         /*
  440          * Record what we've done to the packet (under what SA it was
  441          * processed). If we've been passed an mtag, it means the packet
  442          * was already processed by an ethernet/crypto combo card and
  443          * thus has a tag attached with all the right information, but
  444          * with a PACKET_TAG_IPSEC_IN_CRYPTO_DONE as opposed to
  445          * PACKET_TAG_IPSEC_IN_DONE type; in that case, just change the type.
  446          */
  447         if (mt == NULL && sproto != IPPROTO_IPCOMP) {
  448                 mtag = m_tag_get(PACKET_TAG_IPSEC_IN_DONE,
  449                     sizeof(struct tdb_ident), M_NOWAIT);
  450                 if (mtag == NULL) {
  451                         DPRINTF(("%s: failed to get tag\n", __func__));
  452                         IPSEC_ISTAT(sproto, V_espstat.esps_hdrops,
  453                             V_ahstat.ahs_hdrops, V_ipcompstat.ipcomps_hdrops);
  454                         error = ENOMEM;
  455                         goto bad;
  456                 }
  457 
  458                 tdbi = (struct tdb_ident *)(mtag + 1);
  459                 bcopy(&saidx->dst, &tdbi->dst, saidx->dst.sa.sa_len);
  460                 tdbi->proto = sproto;
  461                 tdbi->spi = sav->spi;
  462                 /* Cache those two for enc(4) in xform_ipip. */
  463                 tdbi->alg_auth = sav->alg_auth;
  464                 tdbi->alg_enc = sav->alg_enc;
  465 
  466                 m_tag_prepend(m, mtag);
  467         } else if (mt != NULL) {
  468                 mt->m_tag_id = PACKET_TAG_IPSEC_IN_DONE;
  469                 /* XXX do we need to mark m_flags??? */
  470         }
  471 
  472         key_sa_recordxfer(sav, m);              /* record data transfer */
  473 
  474 #ifdef DEV_ENC
  475         encif->if_ipackets++;
  476         encif->if_ibytes += m->m_pkthdr.len;
  477 
  478         /*
  479          * Pass the mbuf to enc0 for bpf and pfil. We will filter the IPIP
  480          * packet later after it has been decapsulated.
  481          */
  482         ipsec_bpf(m, sav, AF_INET, ENC_IN|ENC_BEFORE);
  483 
  484         if (prot != IPPROTO_IPIP)
  485                 if ((error = ipsec_filter(&m, PFIL_IN, ENC_IN|ENC_BEFORE)) != 0)
  486                         return (error);
  487 #endif
  488 
  489         /*
  490          * Re-dispatch via software interrupt.
  491          */
  492         if ((error = netisr_queue_src(NETISR_IP, (uintptr_t)sav->spi, m))) {
  493                 IPSEC_ISTAT(sproto, V_espstat.esps_qfull, V_ahstat.ahs_qfull,
  494                             V_ipcompstat.ipcomps_qfull);
  495 
  496                 DPRINTF(("%s: queue full; proto %u packet dropped\n",
  497                         __func__, sproto));
  498                 return error;
  499         }
  500         return 0;
  501 bad:
  502         m_freem(m);
  503         return error;
  504 }
  505 
  506 void
  507 ipsec4_common_ctlinput(int cmd, struct sockaddr *sa, void *v, int proto)
  508 {
  509         /* XXX nothing just yet */
  510 }
  511 #endif /* INET */
  512 
  513 #ifdef INET6
  514 /* IPv6 AH wrapper. */
  515 int
  516 ipsec6_common_input(struct mbuf **mp, int *offp, int proto)
  517 {
  518         int l = 0;
  519         int protoff;
  520         struct ip6_ext ip6e;
  521 
  522         if (*offp < sizeof(struct ip6_hdr)) {
  523                 DPRINTF(("%s: bad offset %u\n", __func__, *offp));
  524                 return IPPROTO_DONE;
  525         } else if (*offp == sizeof(struct ip6_hdr)) {
  526                 protoff = offsetof(struct ip6_hdr, ip6_nxt);
  527         } else {
  528                 /* Chase down the header chain... */
  529                 protoff = sizeof(struct ip6_hdr);
  530 
  531                 do {
  532                         protoff += l;
  533                         m_copydata(*mp, protoff, sizeof(ip6e),
  534                             (caddr_t) &ip6e);
  535 
  536                         if (ip6e.ip6e_nxt == IPPROTO_AH)
  537                                 l = (ip6e.ip6e_len + 2) << 2;
  538                         else
  539                                 l = (ip6e.ip6e_len + 1) << 3;
  540                         IPSEC_ASSERT(l > 0, ("l went zero or negative"));
  541                 } while (protoff + l < *offp);
  542 
  543                 /* Malformed packet check */
  544                 if (protoff + l != *offp) {
  545                         DPRINTF(("%s: bad packet header chain, protoff %u, "
  546                                 "l %u, off %u\n", __func__, protoff, l, *offp));
  547                         IPSEC_ISTAT(proto, V_espstat.esps_hdrops,
  548                                     V_ahstat.ahs_hdrops,
  549                                     V_ipcompstat.ipcomps_hdrops);
  550                         m_freem(*mp);
  551                         *mp = NULL;
  552                         return IPPROTO_DONE;
  553                 }
  554                 protoff += offsetof(struct ip6_ext, ip6e_nxt);
  555         }
  556         (void) ipsec_common_input(*mp, *offp, protoff, AF_INET6, proto);
  557         return IPPROTO_DONE;
  558 }
  559 
  560 /*
  561  * IPsec input callback, called by the transform callback. Takes care of
  562  * filtering and other sanity checks on the processed packet.
  563  */
  564 int
  565 ipsec6_common_input_cb(struct mbuf *m, struct secasvar *sav, int skip, int protoff,
  566     struct m_tag *mt)
  567 {
  568         int prot, af, sproto;
  569         struct ip6_hdr *ip6;
  570         struct m_tag *mtag;
  571         struct tdb_ident *tdbi;
  572         struct secasindex *saidx;
  573         int nxt;
  574         u_int8_t nxt8;
  575         int error, nest;
  576 #ifdef notyet
  577         char ip6buf[INET6_ADDRSTRLEN];
  578 #endif
  579 
  580         IPSEC_ASSERT(m != NULL, ("null mbuf"));
  581         IPSEC_ASSERT(sav != NULL, ("null SA"));
  582         IPSEC_ASSERT(sav->sah != NULL, ("null SAH"));
  583         saidx = &sav->sah->saidx;
  584         af = saidx->dst.sa.sa_family;
  585         IPSEC_ASSERT(af == AF_INET6, ("unexpected af %u", af));
  586         sproto = saidx->proto;
  587         IPSEC_ASSERT(sproto == IPPROTO_ESP || sproto == IPPROTO_AH ||
  588                 sproto == IPPROTO_IPCOMP,
  589                 ("unexpected security protocol %u", sproto));
  590 
  591         /* Sanity check */
  592         if (m == NULL) {
  593                 DPRINTF(("%s: null mbuf", __func__));
  594                 IPSEC_ISTAT(sproto, V_espstat.esps_badkcr, V_ahstat.ahs_badkcr,
  595                     V_ipcompstat.ipcomps_badkcr);
  596                 error = EINVAL;
  597                 goto bad;
  598         }
  599 
  600         /* Fix IPv6 header */
  601         if (m->m_len < sizeof(struct ip6_hdr) &&
  602             (m = m_pullup(m, sizeof(struct ip6_hdr))) == NULL) {
  603 
  604                 DPRINTF(("%s: processing failed for SA %s/%08lx\n",
  605                     __func__, ipsec_address(&sav->sah->saidx.dst),
  606                     (u_long) ntohl(sav->spi)));
  607 
  608                 IPSEC_ISTAT(sproto, V_espstat.esps_hdrops, V_ahstat.ahs_hdrops,
  609                     V_ipcompstat.ipcomps_hdrops);
  610                 error = EACCES;
  611                 goto bad;
  612         }
  613 
  614         ip6 = mtod(m, struct ip6_hdr *);
  615         ip6->ip6_plen = htons(m->m_pkthdr.len - sizeof(struct ip6_hdr));
  616 
  617         /* Save protocol */
  618         m_copydata(m, protoff, 1, (unsigned char *) &prot);
  619 
  620 #ifdef notyet
  621 #ifdef INET
  622         /* IP-in-IP encapsulation */
  623         if (prot == IPPROTO_IPIP) {
  624                 struct ip ipn;
  625 
  626                 if (m->m_pkthdr.len - skip < sizeof(struct ip)) {
  627                         IPSEC_ISTAT(sproto, V_espstat.esps_hdrops,
  628                             V_ahstat.ahs_hdrops,
  629                             V_ipcompstat.ipcomps_hdrops);
  630                         error = EINVAL;
  631                         goto bad;
  632                 }
  633                 /* ipn will now contain the inner IPv4 header */
  634                 m_copydata(m, skip, sizeof(struct ip), (caddr_t) &ipn);
  635 
  636                 /*
  637                  * Check that the inner source address is the same as
  638                  * the proxy address, if available.
  639                  */
  640                 if ((saidx->proxy.sa.sa_family == AF_INET &&
  641                     saidx->proxy.sin.sin_addr.s_addr != INADDR_ANY &&
  642                     ipn.ip_src.s_addr != saidx->proxy.sin.sin_addr.s_addr) ||
  643                     (saidx->proxy.sa.sa_family != AF_INET &&
  644                         saidx->proxy.sa.sa_family != 0)) {
  645 
  646                         DPRINTF(("%s: inner source address %s doesn't "
  647                             "correspond to expected proxy source %s, "
  648                             "SA %s/%08lx\n", __func__,
  649                             inet_ntoa4(ipn.ip_src),
  650                             ipsec_address(&saidx->proxy),
  651                             ipsec_address(&saidx->dst),
  652                             (u_long) ntohl(sav->spi)));
  653 
  654                         IPSEC_ISTATsproto, (V_espstat.esps_pdrops,
  655                             V_ahstat.ahs_pdrops, V_ipcompstat.ipcomps_pdrops);
  656                         error = EACCES;
  657                         goto bad;
  658                 }
  659         }
  660 #endif /* INET */
  661 
  662         /* IPv6-in-IP encapsulation */
  663         if (prot == IPPROTO_IPV6) {
  664                 struct ip6_hdr ip6n;
  665 
  666                 if (m->m_pkthdr.len - skip < sizeof(struct ip6_hdr)) {
  667                         IPSEC_ISTAT(sproto, V_espstat.esps_hdrops,
  668                             V_ahstat.ahs_hdrops,
  669                             V_ipcompstat.ipcomps_hdrops);
  670                         error = EINVAL;
  671                         goto bad;
  672                 }
  673                 /* ip6n will now contain the inner IPv6 header. */
  674                 m_copydata(m, skip, sizeof(struct ip6_hdr),
  675                     (caddr_t) &ip6n);
  676 
  677                 /*
  678                  * Check that the inner source address is the same as
  679                  * the proxy address, if available.
  680                  */
  681                 if ((saidx->proxy.sa.sa_family == AF_INET6 &&
  682                     !IN6_IS_ADDR_UNSPECIFIED(&saidx->proxy.sin6.sin6_addr) &&
  683                     !IN6_ARE_ADDR_EQUAL(&ip6n.ip6_src,
  684                         &saidx->proxy.sin6.sin6_addr)) ||
  685                     (saidx->proxy.sa.sa_family != AF_INET6 &&
  686                         saidx->proxy.sa.sa_family != 0)) {
  687 
  688                         DPRINTF(("%s: inner source address %s doesn't "
  689                             "correspond to expected proxy source %s, "
  690                             "SA %s/%08lx\n", __func__,
  691                             ip6_sprintf(ip6buf, &ip6n.ip6_src),
  692                             ipsec_address(&saidx->proxy),
  693                             ipsec_address(&saidx->dst),
  694                             (u_long) ntohl(sav->spi)));
  695 
  696                         IPSEC_ISTAT(sproto, V_espstat.esps_pdrops,
  697                             V_ahstat.ahs_pdrops, V_ipcompstat.ipcomps_pdrops);
  698                         error = EACCES;
  699                         goto bad;
  700                 }
  701         }
  702 #endif /*XXX*/
  703 
  704         /*
  705          * Record what we've done to the packet (under what SA it was
  706          * processed). If we've been passed an mtag, it means the packet
  707          * was already processed by an ethernet/crypto combo card and
  708          * thus has a tag attached with all the right information, but
  709          * with a PACKET_TAG_IPSEC_IN_CRYPTO_DONE as opposed to
  710          * PACKET_TAG_IPSEC_IN_DONE type; in that case, just change the type.
  711          */
  712         if (mt == NULL && sproto != IPPROTO_IPCOMP) {
  713                 mtag = m_tag_get(PACKET_TAG_IPSEC_IN_DONE,
  714                     sizeof(struct tdb_ident), M_NOWAIT);
  715                 if (mtag == NULL) {
  716                         DPRINTF(("%s: failed to get tag\n", __func__));
  717                         IPSEC_ISTAT(sproto, V_espstat.esps_hdrops,
  718                             V_ahstat.ahs_hdrops, V_ipcompstat.ipcomps_hdrops);
  719                         error = ENOMEM;
  720                         goto bad;
  721                 }
  722 
  723                 tdbi = (struct tdb_ident *)(mtag + 1);
  724                 bcopy(&saidx->dst, &tdbi->dst, sizeof(union sockaddr_union));
  725                 tdbi->proto = sproto;
  726                 tdbi->spi = sav->spi;
  727                 /* Cache those two for enc(4) in xform_ipip. */
  728                 tdbi->alg_auth = sav->alg_auth;
  729                 tdbi->alg_enc = sav->alg_enc;
  730 
  731                 m_tag_prepend(m, mtag);
  732         } else {
  733                 if (mt != NULL)
  734                         mt->m_tag_id = PACKET_TAG_IPSEC_IN_DONE;
  735                 /* XXX do we need to mark m_flags??? */
  736         }
  737 
  738         key_sa_recordxfer(sav, m);
  739 
  740 #ifdef DEV_ENC
  741         encif->if_ipackets++;
  742         encif->if_ibytes += m->m_pkthdr.len;
  743 
  744         /*
  745          * Pass the mbuf to enc0 for bpf and pfil. We will filter the IPIP
  746          * packet later after it has been decapsulated.
  747          */
  748         ipsec_bpf(m, sav, AF_INET6, ENC_IN|ENC_BEFORE);
  749 
  750         /* XXX-BZ does not make sense. */
  751         if (prot != IPPROTO_IPIP)
  752                 if ((error = ipsec_filter(&m, PFIL_IN, ENC_IN|ENC_BEFORE)) != 0)
  753                         return (error);
  754 #endif
  755 
  756         /* Retrieve new protocol */
  757         m_copydata(m, protoff, sizeof(u_int8_t), (caddr_t) &nxt8);
  758 
  759         /*
  760          * See the end of ip6_input for this logic.
  761          * IPPROTO_IPV[46] case will be processed just like other ones
  762          */
  763         nest = 0;
  764         nxt = nxt8;
  765         while (nxt != IPPROTO_DONE) {
  766                 if (V_ip6_hdrnestlimit && (++nest > V_ip6_hdrnestlimit)) {
  767                         V_ip6stat.ip6s_toomanyhdr++;
  768                         error = EINVAL;
  769                         goto bad;
  770                 }
  771 
  772                 /*
  773                  * Protection against faulty packet - there should be
  774                  * more sanity checks in header chain processing.
  775                  */
  776                 if (m->m_pkthdr.len < skip) {
  777                         V_ip6stat.ip6s_tooshort++;
  778                         in6_ifstat_inc(m->m_pkthdr.rcvif, ifs6_in_truncated);
  779                         error = EINVAL;
  780                         goto bad;
  781                 }
  782                 /*
  783                  * Enforce IPsec policy checking if we are seeing last header.
  784                  * note that we do not visit this with protocols with pcb layer
  785                  * code - like udp/tcp/raw ip.
  786                  */
  787                 if ((inet6sw[ip6_protox[nxt]].pr_flags & PR_LASTHDR) != 0 &&
  788                     ipsec6_in_reject(m, NULL)) {
  789                         error = EINVAL;
  790                         goto bad;
  791                 }
  792                 nxt = (*inet6sw[ip6_protox[nxt]].pr_input)(&m, &skip, nxt);
  793         }
  794         return 0;
  795 bad:
  796         if (m)
  797                 m_freem(m);
  798         return error;
  799 }
  800 
  801 void
  802 esp6_ctlinput(int cmd, struct sockaddr *sa, void *d)
  803 {
  804         struct ip6ctlparam *ip6cp = NULL;
  805         struct mbuf *m = NULL;
  806         struct ip6_hdr *ip6;
  807         int off;
  808 
  809         if (sa->sa_family != AF_INET6 ||
  810             sa->sa_len != sizeof(struct sockaddr_in6))
  811                 return;
  812         if ((unsigned)cmd >= PRC_NCMDS)
  813                 return;
  814 
  815         /* if the parameter is from icmp6, decode it. */
  816         if (d != NULL) {
  817                 ip6cp = (struct ip6ctlparam *)d;
  818                 m = ip6cp->ip6c_m;
  819                 ip6 = ip6cp->ip6c_ip6;
  820                 off = ip6cp->ip6c_off;
  821         } else {
  822                 m = NULL;
  823                 ip6 = NULL;
  824                 off = 0;        /* calm gcc */
  825         }
  826 
  827         if (ip6 != NULL) {
  828 
  829                 struct ip6ctlparam ip6cp1;
  830 
  831                 /*
  832                  * Notify the error to all possible sockets via pfctlinput2.
  833                  * Since the upper layer information (such as protocol type,
  834                  * source and destination ports) is embedded in the encrypted
  835                  * data and might have been cut, we can't directly call
  836                  * an upper layer ctlinput function. However, the pcbnotify
  837                  * function will consider source and destination addresses
  838                  * as well as the flow info value, and may be able to find
  839                  * some PCB that should be notified.
  840                  * Although pfctlinput2 will call esp6_ctlinput(), there is
  841                  * no possibility of an infinite loop of function calls,
  842                  * because we don't pass the inner IPv6 header.
  843                  */
  844                 bzero(&ip6cp1, sizeof(ip6cp1));
  845                 ip6cp1.ip6c_src = ip6cp->ip6c_src;
  846                 pfctlinput2(cmd, sa, (void *)&ip6cp1);
  847 
  848                 /*
  849                  * Then go to special cases that need ESP header information.
  850                  * XXX: We assume that when ip6 is non NULL,
  851                  * M and OFF are valid.
  852                  */
  853 
  854                 if (cmd == PRC_MSGSIZE) {
  855                         struct secasvar *sav;
  856                         u_int32_t spi;
  857                         int valid;
  858 
  859                         /* check header length before using m_copydata */
  860                         if (m->m_pkthdr.len < off + sizeof (struct esp))
  861                                 return;
  862                         m_copydata(m, off + offsetof(struct esp, esp_spi),
  863                                 sizeof(u_int32_t), (caddr_t) &spi);
  864                         /*
  865                          * Check to see if we have a valid SA corresponding to
  866                          * the address in the ICMP message payload.
  867                          */
  868                         sav = KEY_ALLOCSA((union sockaddr_union *)sa,
  869                                         IPPROTO_ESP, spi);
  870                         valid = (sav != NULL);
  871                         if (sav)
  872                                 KEY_FREESAV(&sav);
  873 
  874                         /* XXX Further validation? */
  875 
  876                         /*
  877                          * Depending on whether the SA is "valid" and
  878                          * routing table size (mtudisc_{hi,lo}wat), we will:
  879                          * - recalcurate the new MTU and create the
  880                          *   corresponding routing entry, or
  881                          * - ignore the MTU change notification.
  882                          */
  883                         icmp6_mtudisc_update(ip6cp, valid);
  884                 }
  885         } else {
  886                 /* we normally notify any pcb here */
  887         }
  888 }
  889 #endif /* INET6 */

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