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/10.3/sys/netipsec/ipsec_input.c 283901 2015-06-02 03:14:42Z ae $       */
    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/netisr.h>
   61 #include <net/vnet.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 #ifdef DEV_ENC
   97 #include <net/if_enc.h>
   98 #endif
   99 
  100 
  101 #define IPSEC_ISTAT(proto, name)        do {    \
  102         if ((proto) == IPPROTO_ESP)             \
  103                 ESPSTAT_INC(esps_##name);       \
  104         else if ((proto) == IPPROTO_AH)         \
  105                 AHSTAT_INC(ahs_##name);         \
  106         else                                    \
  107                 IPCOMPSTAT_INC(ipcomps_##name); \
  108 } while (0)
  109 
  110 #ifdef INET
  111 static void ipsec4_common_ctlinput(int, struct sockaddr *, void *, int);
  112 #endif
  113 
  114 /*
  115  * ipsec_common_input gets called when an IPsec-protected packet
  116  * is received by IPv4 or IPv6.  Its job is to find the right SA
  117  * and call the appropriate transform.  The transform callback
  118  * takes care of further processing (like ingress filtering).
  119  */
  120 static int
  121 ipsec_common_input(struct mbuf *m, int skip, int protoff, int af, int sproto)
  122 {
  123         union sockaddr_union dst_address;
  124         struct secasvar *sav;
  125         u_int32_t spi;
  126         int error;
  127 #ifdef INET
  128 #ifdef IPSEC_NAT_T
  129         struct m_tag *tag;
  130 #endif
  131 #endif
  132 
  133         IPSEC_ISTAT(sproto, input);
  134 
  135         IPSEC_ASSERT(m != NULL, ("null packet"));
  136 
  137         IPSEC_ASSERT(sproto == IPPROTO_ESP || sproto == IPPROTO_AH ||
  138                 sproto == IPPROTO_IPCOMP,
  139                 ("unexpected security protocol %u", sproto));
  140 
  141         if ((sproto == IPPROTO_ESP && !V_esp_enable) ||
  142             (sproto == IPPROTO_AH && !V_ah_enable) ||
  143             (sproto == IPPROTO_IPCOMP && !V_ipcomp_enable)) {
  144                 m_freem(m);
  145                 IPSEC_ISTAT(sproto, pdrops);
  146                 return EOPNOTSUPP;
  147         }
  148 
  149         if (m->m_pkthdr.len - skip < 2 * sizeof (u_int32_t)) {
  150                 m_freem(m);
  151                 IPSEC_ISTAT(sproto, hdrops);
  152                 DPRINTF(("%s: packet too small\n", __func__));
  153                 return EINVAL;
  154         }
  155 
  156         /* Retrieve the SPI from the relevant IPsec header */
  157         if (sproto == IPPROTO_ESP)
  158                 m_copydata(m, skip, sizeof(u_int32_t), (caddr_t) &spi);
  159         else if (sproto == IPPROTO_AH)
  160                 m_copydata(m, skip + sizeof(u_int32_t), sizeof(u_int32_t),
  161                     (caddr_t) &spi);
  162         else if (sproto == IPPROTO_IPCOMP) {
  163                 u_int16_t cpi;
  164                 m_copydata(m, skip + sizeof(u_int16_t), sizeof(u_int16_t),
  165                     (caddr_t) &cpi);
  166                 spi = ntohl(htons(cpi));
  167         }
  168 
  169         /*
  170          * Find the SA and (indirectly) call the appropriate
  171          * kernel crypto routine. The resulting mbuf chain is a valid
  172          * IP packet ready to go through input processing.
  173          */
  174         bzero(&dst_address, sizeof (dst_address));
  175         dst_address.sa.sa_family = af;
  176         switch (af) {
  177 #ifdef INET
  178         case AF_INET:
  179                 dst_address.sin.sin_len = sizeof(struct sockaddr_in);
  180                 m_copydata(m, offsetof(struct ip, ip_dst),
  181                     sizeof(struct in_addr),
  182                     (caddr_t) &dst_address.sin.sin_addr);
  183 #ifdef IPSEC_NAT_T
  184                 /* Find the source port for NAT-T; see udp*_espdecap. */
  185                 tag = m_tag_find(m, PACKET_TAG_IPSEC_NAT_T_PORTS, NULL);
  186                 if (tag != NULL)
  187                         dst_address.sin.sin_port = ((u_int16_t *)(tag + 1))[1];
  188 #endif /* IPSEC_NAT_T */
  189                 break;
  190 #endif /* INET */
  191 #ifdef INET6
  192         case AF_INET6:
  193                 dst_address.sin6.sin6_len = sizeof(struct sockaddr_in6);
  194                 m_copydata(m, offsetof(struct ip6_hdr, ip6_dst),
  195                     sizeof(struct in6_addr),
  196                     (caddr_t) &dst_address.sin6.sin6_addr);
  197                 break;
  198 #endif /* INET6 */
  199         default:
  200                 DPRINTF(("%s: unsupported protocol family %u\n", __func__, af));
  201                 m_freem(m);
  202                 IPSEC_ISTAT(sproto, nopf);
  203                 return EPFNOSUPPORT;
  204         }
  205 
  206         /* NB: only pass dst since key_allocsa follows RFC2401 */
  207         sav = KEY_ALLOCSA(&dst_address, sproto, spi);
  208         if (sav == NULL) {
  209                 DPRINTF(("%s: no key association found for SA %s/%08lx/%u\n",
  210                           __func__, ipsec_address(&dst_address),
  211                           (u_long) ntohl(spi), sproto));
  212                 IPSEC_ISTAT(sproto, notdb);
  213                 m_freem(m);
  214                 return ENOENT;
  215         }
  216 
  217         if (sav->tdb_xform == NULL) {
  218                 DPRINTF(("%s: attempted to use uninitialized SA %s/%08lx/%u\n",
  219                          __func__, ipsec_address(&dst_address),
  220                          (u_long) ntohl(spi), sproto));
  221                 IPSEC_ISTAT(sproto, noxform);
  222                 KEY_FREESAV(&sav);
  223                 m_freem(m);
  224                 return ENXIO;
  225         }
  226 
  227         /*
  228          * Call appropriate transform and return -- callback takes care of
  229          * everything else.
  230          */
  231         error = (*sav->tdb_xform->xf_input)(m, sav, skip, protoff);
  232         KEY_FREESAV(&sav);
  233         return error;
  234 }
  235 
  236 #ifdef INET
  237 /*
  238  * Common input handler for IPv4 AH, ESP, and IPCOMP.
  239  */
  240 int
  241 ipsec4_common_input(struct mbuf *m, ...)
  242 {
  243         va_list ap;
  244         int off, nxt;
  245 
  246         va_start(ap, m);
  247         off = va_arg(ap, int);
  248         nxt = va_arg(ap, int);
  249         va_end(ap);
  250 
  251         return ipsec_common_input(m, off, offsetof(struct ip, ip_p),
  252                                   AF_INET, nxt);
  253 }
  254 
  255 void
  256 ah4_input(struct mbuf *m, int off)
  257 {
  258         ipsec4_common_input(m, off, IPPROTO_AH);
  259 }
  260 void
  261 ah4_ctlinput(int cmd, struct sockaddr *sa, void *v)
  262 {
  263         if (sa->sa_family == AF_INET &&
  264             sa->sa_len == sizeof(struct sockaddr_in))
  265                 ipsec4_common_ctlinput(cmd, sa, v, IPPROTO_AH);
  266 }
  267 
  268 void
  269 esp4_input(struct mbuf *m, int off)
  270 {
  271         ipsec4_common_input(m, off, IPPROTO_ESP);
  272 }
  273 void
  274 esp4_ctlinput(int cmd, struct sockaddr *sa, void *v)
  275 {
  276         if (sa->sa_family == AF_INET &&
  277             sa->sa_len == sizeof(struct sockaddr_in))
  278                 ipsec4_common_ctlinput(cmd, sa, v, IPPROTO_ESP);
  279 }
  280 
  281 void
  282 ipcomp4_input(struct mbuf *m, int off)
  283 {
  284         ipsec4_common_input(m, off, IPPROTO_IPCOMP);
  285 }
  286 
  287 /*
  288  * IPsec input callback for INET protocols.
  289  * This routine is called as the transform callback.
  290  * Takes care of filtering and other sanity checks on
  291  * the processed packet.
  292  */
  293 int
  294 ipsec4_common_input_cb(struct mbuf *m, struct secasvar *sav,
  295                         int skip, int protoff, struct m_tag *mt)
  296 {
  297         int prot, af, sproto, isr_prot;
  298         struct ip *ip;
  299         struct m_tag *mtag;
  300         struct tdb_ident *tdbi;
  301         struct secasindex *saidx;
  302         int error;
  303 #ifdef INET6
  304 #ifdef notyet
  305         char ip6buf[INET6_ADDRSTRLEN];
  306 #endif
  307 #endif
  308 
  309         IPSEC_ASSERT(m != NULL, ("null mbuf"));
  310         IPSEC_ASSERT(sav != NULL, ("null SA"));
  311         IPSEC_ASSERT(sav->sah != NULL, ("null SAH"));
  312         saidx = &sav->sah->saidx;
  313         af = saidx->dst.sa.sa_family;
  314         IPSEC_ASSERT(af == AF_INET, ("unexpected af %u", af));
  315         sproto = saidx->proto;
  316         IPSEC_ASSERT(sproto == IPPROTO_ESP || sproto == IPPROTO_AH ||
  317                 sproto == IPPROTO_IPCOMP,
  318                 ("unexpected security protocol %u", sproto));
  319 
  320         /* Sanity check */
  321         if (m == NULL) {
  322                 DPRINTF(("%s: null mbuf", __func__));
  323                 IPSEC_ISTAT(sproto, badkcr);
  324                 KEY_FREESAV(&sav);
  325                 return EINVAL;
  326         }
  327 
  328         if (skip != 0) {
  329                 /*
  330                  * Fix IPv4 header
  331                  * XXXGL: do we need this entire block?
  332                  */
  333                 if (m->m_len < skip && (m = m_pullup(m, skip)) == NULL) {
  334                         DPRINTF(("%s: processing failed for SA %s/%08lx\n",
  335                             __func__, ipsec_address(&sav->sah->saidx.dst),
  336                             (u_long) ntohl(sav->spi)));
  337                         IPSEC_ISTAT(sproto, hdrops);
  338                         error = ENOBUFS;
  339                         goto bad;
  340                 }
  341 
  342                 ip = mtod(m, struct ip *);
  343                 ip->ip_len = htons(m->m_pkthdr.len);
  344                 ip->ip_sum = 0;
  345                 ip->ip_sum = in_cksum(m, ip->ip_hl << 2);
  346         } else {
  347                 ip = mtod(m, struct ip *);
  348         }
  349         prot = ip->ip_p;
  350 
  351 #ifdef DEV_ENC
  352         encif->if_ipackets++;
  353         encif->if_ibytes += m->m_pkthdr.len;
  354 
  355         /* Pass the mbuf to enc0 for bpf and pfil. */
  356         ipsec_bpf(m, sav, AF_INET, ENC_IN|ENC_BEFORE);
  357         if ((error = ipsec_filter(&m, PFIL_IN, ENC_IN|ENC_BEFORE)) != 0)
  358                 return (error);
  359 #endif /* DEV_ENC */
  360 
  361         /* IP-in-IP encapsulation */
  362         if (prot == IPPROTO_IPIP &&
  363             saidx->mode != IPSEC_MODE_TRANSPORT) {
  364 
  365                 if (m->m_pkthdr.len - skip < sizeof(struct ip)) {
  366                         IPSEC_ISTAT(sproto, hdrops);
  367                         error = EINVAL;
  368                         goto bad;
  369                 }
  370                 /* enc0: strip outer IPv4 header */
  371                 m_striphdr(m, 0, ip->ip_hl << 2);
  372 
  373 #ifdef notyet
  374                 /* XXX PROXY address isn't recorded in SAH */
  375                 /*
  376                  * Check that the inner source address is the same as
  377                  * the proxy address, if available.
  378                  */
  379                 if ((saidx->proxy.sa.sa_family == AF_INET &&
  380                     saidx->proxy.sin.sin_addr.s_addr !=
  381                     INADDR_ANY &&
  382                     ipn.ip_src.s_addr !=
  383                     saidx->proxy.sin.sin_addr.s_addr) ||
  384                     (saidx->proxy.sa.sa_family != AF_INET &&
  385                         saidx->proxy.sa.sa_family != 0)) {
  386 
  387                         DPRINTF(("%s: inner source address %s doesn't "
  388                             "correspond to expected proxy source %s, "
  389                             "SA %s/%08lx\n", __func__,
  390                             inet_ntoa4(ipn.ip_src),
  391                             ipsp_address(saidx->proxy),
  392                             ipsp_address(saidx->dst),
  393                             (u_long) ntohl(sav->spi)));
  394 
  395                         IPSEC_ISTAT(sproto, pdrops);
  396                         error = EACCES;
  397                         goto bad;
  398                 }
  399 #endif /* notyet */
  400         }
  401 #ifdef INET6
  402         /* IPv6-in-IP encapsulation. */
  403         else if (prot == IPPROTO_IPV6 &&
  404             saidx->mode != IPSEC_MODE_TRANSPORT) {
  405 
  406                 if (m->m_pkthdr.len - skip < sizeof(struct ip6_hdr)) {
  407                         IPSEC_ISTAT(sproto, hdrops);
  408                         error = EINVAL;
  409                         goto bad;
  410                 }
  411                 /* enc0: strip IPv4 header, keep IPv6 header only */
  412                 m_striphdr(m, 0, ip->ip_hl << 2);
  413 #ifdef notyet 
  414                 /*
  415                  * Check that the inner source address is the same as
  416                  * the proxy address, if available.
  417                  */
  418                 if ((saidx->proxy.sa.sa_family == AF_INET6 &&
  419                     !IN6_IS_ADDR_UNSPECIFIED(&saidx->proxy.sin6.sin6_addr) &&
  420                     !IN6_ARE_ADDR_EQUAL(&ip6n.ip6_src,
  421                         &saidx->proxy.sin6.sin6_addr)) ||
  422                     (saidx->proxy.sa.sa_family != AF_INET6 &&
  423                         saidx->proxy.sa.sa_family != 0)) {
  424 
  425                         DPRINTF(("%s: inner source address %s doesn't "
  426                             "correspond to expected proxy source %s, "
  427                             "SA %s/%08lx\n", __func__,
  428                             ip6_sprintf(ip6buf, &ip6n.ip6_src),
  429                             ipsec_address(&saidx->proxy),
  430                             ipsec_address(&saidx->dst),
  431                             (u_long) ntohl(sav->spi)));
  432 
  433                         IPSEC_ISTAT(sproto, pdrops);
  434                         error = EACCES;
  435                         goto bad;
  436                 }
  437 #endif /* notyet */
  438         }
  439 #endif /* INET6 */
  440         else if (prot != IPPROTO_IPV6 && saidx->mode == IPSEC_MODE_ANY) {
  441                 /*
  442                  * When mode is wildcard, inner protocol is IPv6 and
  443                  * we have no INET6 support - drop this packet a bit later.
  444                  * In other cases we assume transport mode and outer
  445                  * header was already stripped in xform_xxx_cb.
  446                  */
  447                 prot = IPPROTO_IPIP;
  448         }
  449 
  450         /*
  451          * Record what we've done to the packet (under what SA it was
  452          * processed). If we've been passed an mtag, it means the packet
  453          * was already processed by an ethernet/crypto combo card and
  454          * thus has a tag attached with all the right information, but
  455          * with a PACKET_TAG_IPSEC_IN_CRYPTO_DONE as opposed to
  456          * PACKET_TAG_IPSEC_IN_DONE type; in that case, just change the type.
  457          */
  458         if (mt == NULL && sproto != IPPROTO_IPCOMP) {
  459                 mtag = m_tag_get(PACKET_TAG_IPSEC_IN_DONE,
  460                     sizeof(struct tdb_ident), M_NOWAIT);
  461                 if (mtag == NULL) {
  462                         DPRINTF(("%s: failed to get tag\n", __func__));
  463                         IPSEC_ISTAT(sproto, hdrops);
  464                         error = ENOMEM;
  465                         goto bad;
  466                 }
  467 
  468                 tdbi = (struct tdb_ident *)(mtag + 1);
  469                 bcopy(&saidx->dst, &tdbi->dst, saidx->dst.sa.sa_len);
  470                 tdbi->proto = sproto;
  471                 tdbi->spi = sav->spi;
  472                 /* Cache those two for enc(4) in xform_ipip. */
  473                 tdbi->alg_auth = sav->alg_auth;
  474                 tdbi->alg_enc = sav->alg_enc;
  475 
  476                 m_tag_prepend(m, mtag);
  477         } else if (mt != NULL) {
  478                 mt->m_tag_id = PACKET_TAG_IPSEC_IN_DONE;
  479                 /* XXX do we need to mark m_flags??? */
  480         }
  481 
  482         key_sa_recordxfer(sav, m);              /* record data transfer */
  483 
  484         /*
  485          * In transport mode requeue decrypted mbuf back to IPv4 protocol
  486          * handler. This is necessary to correctly expose rcvif.
  487          */
  488         if (saidx->mode == IPSEC_MODE_TRANSPORT)
  489                 prot = IPPROTO_IPIP;
  490 #ifdef DEV_ENC
  491         /*
  492          * Pass the mbuf to enc0 for bpf and pfil.
  493          */
  494         if (prot == IPPROTO_IPIP)
  495                 ipsec_bpf(m, sav, AF_INET, ENC_IN|ENC_AFTER);
  496 #ifdef INET6
  497         if (prot == IPPROTO_IPV6)
  498                 ipsec_bpf(m, sav, AF_INET6, ENC_IN|ENC_AFTER);
  499 #endif
  500 
  501         if ((error = ipsec_filter(&m, PFIL_IN, ENC_IN|ENC_AFTER)) != 0)
  502                 return (error);
  503 #endif /* DEV_ENC */
  504 
  505         /*
  506          * Re-dispatch via software interrupt.
  507          */
  508 
  509         switch (prot) {
  510         case IPPROTO_IPIP:
  511                 isr_prot = NETISR_IP;
  512                 break;
  513 #ifdef INET6
  514         case IPPROTO_IPV6:
  515                 isr_prot = NETISR_IPV6;
  516                 break;
  517 #endif
  518         default:
  519                 DPRINTF(("%s: cannot handle inner ip proto %d\n",
  520                             __func__, prot));
  521                 IPSEC_ISTAT(sproto, nopf);
  522                 error = EPFNOSUPPORT;
  523                 goto bad;
  524         }
  525 
  526         error = netisr_queue_src(isr_prot, (uintptr_t)sav->spi, m);
  527         if (error) {
  528                 IPSEC_ISTAT(sproto, qfull);
  529                 DPRINTF(("%s: queue full; proto %u packet dropped\n",
  530                         __func__, sproto));
  531                 return error;
  532         }
  533         return 0;
  534 bad:
  535         m_freem(m);
  536         return error;
  537 }
  538 
  539 void
  540 ipsec4_common_ctlinput(int cmd, struct sockaddr *sa, void *v, int proto)
  541 {
  542         /* XXX nothing just yet */
  543 }
  544 #endif /* INET */
  545 
  546 #ifdef INET6
  547 /* IPv6 AH wrapper. */
  548 int
  549 ipsec6_common_input(struct mbuf **mp, int *offp, int proto)
  550 {
  551         int l = 0;
  552         int protoff;
  553         struct ip6_ext ip6e;
  554 
  555         if (*offp < sizeof(struct ip6_hdr)) {
  556                 DPRINTF(("%s: bad offset %u\n", __func__, *offp));
  557                 return IPPROTO_DONE;
  558         } else if (*offp == sizeof(struct ip6_hdr)) {
  559                 protoff = offsetof(struct ip6_hdr, ip6_nxt);
  560         } else {
  561                 /* Chase down the header chain... */
  562                 protoff = sizeof(struct ip6_hdr);
  563 
  564                 do {
  565                         protoff += l;
  566                         m_copydata(*mp, protoff, sizeof(ip6e),
  567                             (caddr_t) &ip6e);
  568 
  569                         if (ip6e.ip6e_nxt == IPPROTO_AH)
  570                                 l = (ip6e.ip6e_len + 2) << 2;
  571                         else
  572                                 l = (ip6e.ip6e_len + 1) << 3;
  573                         IPSEC_ASSERT(l > 0, ("l went zero or negative"));
  574                 } while (protoff + l < *offp);
  575 
  576                 /* Malformed packet check */
  577                 if (protoff + l != *offp) {
  578                         DPRINTF(("%s: bad packet header chain, protoff %u, "
  579                                 "l %u, off %u\n", __func__, protoff, l, *offp));
  580                         IPSEC_ISTAT(proto, hdrops);
  581                         m_freem(*mp);
  582                         *mp = NULL;
  583                         return IPPROTO_DONE;
  584                 }
  585                 protoff += offsetof(struct ip6_ext, ip6e_nxt);
  586         }
  587         (void) ipsec_common_input(*mp, *offp, protoff, AF_INET6, proto);
  588         return IPPROTO_DONE;
  589 }
  590 
  591 /*
  592  * IPsec input callback, called by the transform callback. Takes care of
  593  * filtering and other sanity checks on the processed packet.
  594  */
  595 int
  596 ipsec6_common_input_cb(struct mbuf *m, struct secasvar *sav, int skip, int protoff,
  597     struct m_tag *mt)
  598 {
  599         int prot, af, sproto;
  600         struct ip6_hdr *ip6;
  601         struct m_tag *mtag;
  602         struct tdb_ident *tdbi;
  603         struct secasindex *saidx;
  604         int nxt;
  605         u_int8_t nxt8;
  606         int error, nest;
  607 #ifdef notyet
  608         char ip6buf[INET6_ADDRSTRLEN];
  609 #endif
  610 
  611         IPSEC_ASSERT(m != NULL, ("null mbuf"));
  612         IPSEC_ASSERT(sav != NULL, ("null SA"));
  613         IPSEC_ASSERT(sav->sah != NULL, ("null SAH"));
  614         saidx = &sav->sah->saidx;
  615         af = saidx->dst.sa.sa_family;
  616         IPSEC_ASSERT(af == AF_INET6, ("unexpected af %u", af));
  617         sproto = saidx->proto;
  618         IPSEC_ASSERT(sproto == IPPROTO_ESP || sproto == IPPROTO_AH ||
  619                 sproto == IPPROTO_IPCOMP,
  620                 ("unexpected security protocol %u", sproto));
  621 
  622         /* Sanity check */
  623         if (m == NULL) {
  624                 DPRINTF(("%s: null mbuf", __func__));
  625                 IPSEC_ISTAT(sproto, badkcr);
  626                 error = EINVAL;
  627                 goto bad;
  628         }
  629 
  630         /* Fix IPv6 header */
  631         if (m->m_len < sizeof(struct ip6_hdr) &&
  632             (m = m_pullup(m, sizeof(struct ip6_hdr))) == NULL) {
  633 
  634                 DPRINTF(("%s: processing failed for SA %s/%08lx\n",
  635                     __func__, ipsec_address(&sav->sah->saidx.dst),
  636                     (u_long) ntohl(sav->spi)));
  637 
  638                 IPSEC_ISTAT(sproto, hdrops);
  639                 error = EACCES;
  640                 goto bad;
  641         }
  642 
  643         ip6 = mtod(m, struct ip6_hdr *);
  644         ip6->ip6_plen = htons(m->m_pkthdr.len - sizeof(struct ip6_hdr));
  645 
  646         /* Save protocol */
  647         m_copydata(m, protoff, 1, &nxt8);
  648         prot = nxt8;
  649 
  650 #ifdef DEV_ENC
  651         encif->if_ipackets++;
  652         encif->if_ibytes += m->m_pkthdr.len;
  653 
  654         /* Pass the mbuf to enc0 for bpf and pfil. */
  655         ipsec_bpf(m, sav, AF_INET6, ENC_IN|ENC_BEFORE);
  656         if ((error = ipsec_filter(&m, PFIL_IN, ENC_IN|ENC_BEFORE)) != 0)
  657                 return (error);
  658 #endif /* DEV_ENC */
  659 
  660         /* IPv6-in-IP encapsulation */
  661         if (prot == IPPROTO_IPV6 &&
  662             saidx->mode != IPSEC_MODE_TRANSPORT) {
  663                 if (m->m_pkthdr.len - skip < sizeof(struct ip6_hdr)) {
  664                         IPSEC_ISTAT(sproto, hdrops);
  665                         error = EINVAL;
  666                         goto bad;
  667                 }
  668                 /* ip6n will now contain the inner IPv6 header. */
  669                 m_striphdr(m, 0, skip);
  670                 skip = 0;
  671 #ifdef notyet
  672                 /*
  673                  * Check that the inner source address is the same as
  674                  * the proxy address, if available.
  675                  */
  676                 if ((saidx->proxy.sa.sa_family == AF_INET6 &&
  677                     !IN6_IS_ADDR_UNSPECIFIED(&saidx->proxy.sin6.sin6_addr) &&
  678                     !IN6_ARE_ADDR_EQUAL(&ip6n.ip6_src,
  679                         &saidx->proxy.sin6.sin6_addr)) ||
  680                     (saidx->proxy.sa.sa_family != AF_INET6 &&
  681                         saidx->proxy.sa.sa_family != 0)) {
  682 
  683                         DPRINTF(("%s: inner source address %s doesn't "
  684                             "correspond to expected proxy source %s, "
  685                             "SA %s/%08lx\n", __func__,
  686                             ip6_sprintf(ip6buf, &ip6n.ip6_src),
  687                             ipsec_address(&saidx->proxy),
  688                             ipsec_address(&saidx->dst),
  689                             (u_long) ntohl(sav->spi)));
  690 
  691                         IPSEC_ISTAT(sproto, pdrops);
  692                         error = EACCES;
  693                         goto bad;
  694                 }
  695 #endif /* notyet */
  696         }
  697 #ifdef INET
  698         /* IP-in-IP encapsulation */
  699         else if (prot == IPPROTO_IPIP &&
  700             saidx->mode != IPSEC_MODE_TRANSPORT) {
  701                 if (m->m_pkthdr.len - skip < sizeof(struct ip)) {
  702                         IPSEC_ISTAT(sproto, hdrops);
  703                         error = EINVAL;
  704                         goto bad;
  705                 }
  706                 /* ipn will now contain the inner IPv4 header */
  707                 m_striphdr(m, 0, skip);
  708                 skip = 0;
  709 #ifdef notyet
  710                 /*
  711                  * Check that the inner source address is the same as
  712                  * the proxy address, if available.
  713                  */
  714                 if ((saidx->proxy.sa.sa_family == AF_INET &&
  715                     saidx->proxy.sin.sin_addr.s_addr != INADDR_ANY &&
  716                     ipn.ip_src.s_addr != saidx->proxy.sin.sin_addr.s_addr) ||
  717                     (saidx->proxy.sa.sa_family != AF_INET &&
  718                         saidx->proxy.sa.sa_family != 0)) {
  719 
  720                         DPRINTF(("%s: inner source address %s doesn't "
  721                             "correspond to expected proxy source %s, "
  722                             "SA %s/%08lx\n", __func__,
  723                             inet_ntoa4(ipn.ip_src),
  724                             ipsec_address(&saidx->proxy),
  725                             ipsec_address(&saidx->dst),
  726                             (u_long) ntohl(sav->spi)));
  727 
  728                         IPSEC_ISTAT(sproto, pdrops);
  729                         error = EACCES;
  730                         goto bad;
  731                 }
  732 #endif /* notyet */
  733         }
  734 #endif /* INET */
  735         else {
  736                 prot = IPPROTO_IPV6; /* for correct BPF processing */
  737         }
  738 
  739         /*
  740          * Record what we've done to the packet (under what SA it was
  741          * processed). If we've been passed an mtag, it means the packet
  742          * was already processed by an ethernet/crypto combo card and
  743          * thus has a tag attached with all the right information, but
  744          * with a PACKET_TAG_IPSEC_IN_CRYPTO_DONE as opposed to
  745          * PACKET_TAG_IPSEC_IN_DONE type; in that case, just change the type.
  746          */
  747         if (mt == NULL && sproto != IPPROTO_IPCOMP) {
  748                 mtag = m_tag_get(PACKET_TAG_IPSEC_IN_DONE,
  749                     sizeof(struct tdb_ident), M_NOWAIT);
  750                 if (mtag == NULL) {
  751                         DPRINTF(("%s: failed to get tag\n", __func__));
  752                         IPSEC_ISTAT(sproto, hdrops);
  753                         error = ENOMEM;
  754                         goto bad;
  755                 }
  756 
  757                 tdbi = (struct tdb_ident *)(mtag + 1);
  758                 bcopy(&saidx->dst, &tdbi->dst, sizeof(union sockaddr_union));
  759                 tdbi->proto = sproto;
  760                 tdbi->spi = sav->spi;
  761                 /* Cache those two for enc(4) in xform_ipip. */
  762                 tdbi->alg_auth = sav->alg_auth;
  763                 tdbi->alg_enc = sav->alg_enc;
  764 
  765                 m_tag_prepend(m, mtag);
  766         } else {
  767                 if (mt != NULL)
  768                         mt->m_tag_id = PACKET_TAG_IPSEC_IN_DONE;
  769                 /* XXX do we need to mark m_flags??? */
  770         }
  771 
  772         key_sa_recordxfer(sav, m);
  773 
  774 #ifdef DEV_ENC
  775         /*
  776          * Pass the mbuf to enc0 for bpf and pfil.
  777          */
  778 #ifdef INET
  779         if (prot == IPPROTO_IPIP)
  780                 ipsec_bpf(m, sav, AF_INET, ENC_IN|ENC_AFTER);
  781 #endif
  782         if (prot == IPPROTO_IPV6)
  783                 ipsec_bpf(m, sav, AF_INET6, ENC_IN|ENC_AFTER);
  784 
  785         if ((error = ipsec_filter(&m, PFIL_IN, ENC_IN|ENC_AFTER)) != 0)
  786                 return (error);
  787 #endif /* DEV_ENC */
  788         /*
  789          * See the end of ip6_input for this logic.
  790          * IPPROTO_IPV[46] case will be processed just like other ones
  791          */
  792         nest = 0;
  793         nxt = nxt8;
  794         while (nxt != IPPROTO_DONE) {
  795                 if (V_ip6_hdrnestlimit && (++nest > V_ip6_hdrnestlimit)) {
  796                         IP6STAT_INC(ip6s_toomanyhdr);
  797                         error = EINVAL;
  798                         goto bad;
  799                 }
  800 
  801                 /*
  802                  * Protection against faulty packet - there should be
  803                  * more sanity checks in header chain processing.
  804                  */
  805                 if (m->m_pkthdr.len < skip) {
  806                         IP6STAT_INC(ip6s_tooshort);
  807                         in6_ifstat_inc(m->m_pkthdr.rcvif, ifs6_in_truncated);
  808                         error = EINVAL;
  809                         goto bad;
  810                 }
  811                 /*
  812                  * Enforce IPsec policy checking if we are seeing last header.
  813                  * note that we do not visit this with protocols with pcb layer
  814                  * code - like udp/tcp/raw ip.
  815                  */
  816                 if ((inet6sw[ip6_protox[nxt]].pr_flags & PR_LASTHDR) != 0 &&
  817                     ipsec6_in_reject(m, NULL)) {
  818                         error = EINVAL;
  819                         goto bad;
  820                 }
  821                 nxt = (*inet6sw[ip6_protox[nxt]].pr_input)(&m, &skip, nxt);
  822         }
  823         return 0;
  824 bad:
  825         if (m)
  826                 m_freem(m);
  827         return error;
  828 }
  829 
  830 void
  831 esp6_ctlinput(int cmd, struct sockaddr *sa, void *d)
  832 {
  833         struct ip6ctlparam *ip6cp = NULL;
  834         struct mbuf *m = NULL;
  835         struct ip6_hdr *ip6;
  836         int off;
  837 
  838         if (sa->sa_family != AF_INET6 ||
  839             sa->sa_len != sizeof(struct sockaddr_in6))
  840                 return;
  841         if ((unsigned)cmd >= PRC_NCMDS)
  842                 return;
  843 
  844         /* if the parameter is from icmp6, decode it. */
  845         if (d != NULL) {
  846                 ip6cp = (struct ip6ctlparam *)d;
  847                 m = ip6cp->ip6c_m;
  848                 ip6 = ip6cp->ip6c_ip6;
  849                 off = ip6cp->ip6c_off;
  850         } else {
  851                 m = NULL;
  852                 ip6 = NULL;
  853                 off = 0;        /* calm gcc */
  854         }
  855 
  856         if (ip6 != NULL) {
  857 
  858                 struct ip6ctlparam ip6cp1;
  859 
  860                 /*
  861                  * Notify the error to all possible sockets via pfctlinput2.
  862                  * Since the upper layer information (such as protocol type,
  863                  * source and destination ports) is embedded in the encrypted
  864                  * data and might have been cut, we can't directly call
  865                  * an upper layer ctlinput function. However, the pcbnotify
  866                  * function will consider source and destination addresses
  867                  * as well as the flow info value, and may be able to find
  868                  * some PCB that should be notified.
  869                  * Although pfctlinput2 will call esp6_ctlinput(), there is
  870                  * no possibility of an infinite loop of function calls,
  871                  * because we don't pass the inner IPv6 header.
  872                  */
  873                 bzero(&ip6cp1, sizeof(ip6cp1));
  874                 ip6cp1.ip6c_src = ip6cp->ip6c_src;
  875                 pfctlinput2(cmd, sa, (void *)&ip6cp1);
  876 
  877                 /*
  878                  * Then go to special cases that need ESP header information.
  879                  * XXX: We assume that when ip6 is non NULL,
  880                  * M and OFF are valid.
  881                  */
  882 
  883                 if (cmd == PRC_MSGSIZE) {
  884                         struct secasvar *sav;
  885                         u_int32_t spi;
  886                         int valid;
  887 
  888                         /* check header length before using m_copydata */
  889                         if (m->m_pkthdr.len < off + sizeof (struct esp))
  890                                 return;
  891                         m_copydata(m, off + offsetof(struct esp, esp_spi),
  892                                 sizeof(u_int32_t), (caddr_t) &spi);
  893                         /*
  894                          * Check to see if we have a valid SA corresponding to
  895                          * the address in the ICMP message payload.
  896                          */
  897                         sav = KEY_ALLOCSA((union sockaddr_union *)sa,
  898                                         IPPROTO_ESP, spi);
  899                         valid = (sav != NULL);
  900                         if (sav)
  901                                 KEY_FREESAV(&sav);
  902 
  903                         /* XXX Further validation? */
  904 
  905                         /*
  906                          * Depending on whether the SA is "valid" and
  907                          * routing table size (mtudisc_{hi,lo}wat), we will:
  908                          * - recalcurate the new MTU and create the
  909                          *   corresponding routing entry, or
  910                          * - ignore the MTU change notification.
  911                          */
  912                         icmp6_mtudisc_update(ip6cp, valid);
  913                 }
  914         } else {
  915                 /* we normally notify any pcb here */
  916         }
  917 }
  918 #endif /* INET6 */

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