The Design and Implementation of the FreeBSD Operating System, Second Edition
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sys/netipsec/xform_esp.c

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    1 /*      $FreeBSD: releng/5.4/sys/netipsec/xform_esp.c 157000 2006-03-22 16:03:25Z cperciva $    */
    2 /*      $OpenBSD: ip_esp.c,v 1.69 2001/06/26 06:18:59 angelos 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  * The original version of this code was written by John Ioannidis
    9  * for BSD/OS in Athens, Greece, 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 #include "opt_inet.h"
   39 #include "opt_inet6.h"
   40 
   41 #include <sys/param.h>
   42 #include <sys/systm.h>
   43 #include <sys/mbuf.h>
   44 #include <sys/socket.h>
   45 #include <sys/syslog.h>
   46 #include <sys/kernel.h>
   47 #include <sys/random.h>
   48 #include <sys/sysctl.h>
   49 
   50 #include <net/if.h>
   51 
   52 #include <netinet/in.h>
   53 #include <netinet/in_systm.h>
   54 #include <netinet/ip.h>
   55 #include <netinet/ip_ecn.h>
   56 #include <netinet/ip6.h>
   57 
   58 #include <net/route.h>
   59 #include <netipsec/ipsec.h>
   60 #include <netipsec/ah.h>
   61 #include <netipsec/ah_var.h>
   62 #include <netipsec/esp.h>
   63 #include <netipsec/esp_var.h>
   64 #include <netipsec/xform.h>
   65 
   66 #ifdef INET6
   67 #include <netinet6/ip6_var.h>
   68 #include <netipsec/ipsec6.h>
   69 #include <netinet6/ip6_ecn.h>
   70 #endif
   71 
   72 #include <netipsec/key.h>
   73 #include <netipsec/key_debug.h>
   74 
   75 #include <opencrypto/cryptodev.h>
   76 #include <opencrypto/xform.h>
   77 
   78 int     esp_enable = 1;
   79 struct  espstat espstat;
   80 
   81 SYSCTL_DECL(_net_inet_esp);
   82 SYSCTL_INT(_net_inet_esp, OID_AUTO,
   83         esp_enable,     CTLFLAG_RW,     &esp_enable,    0, "");
   84 SYSCTL_STRUCT(_net_inet_esp, IPSECCTL_STATS,
   85         stats,          CTLFLAG_RD,     &espstat,       espstat, "");
   86 
   87 static  int esp_max_ivlen;              /* max iv length over all algorithms */
   88 
   89 static int esp_input_cb(struct cryptop *op);
   90 static int esp_output_cb(struct cryptop *crp);
   91 
   92 /*
   93  * NB: this is public for use by the PF_KEY support.
   94  * NB: if you add support here; be sure to add code to esp_attach below!
   95  */
   96 struct enc_xform *
   97 esp_algorithm_lookup(int alg)
   98 {
   99         if (alg >= ESP_ALG_MAX)
  100                 return NULL;
  101         switch (alg) {
  102         case SADB_EALG_DESCBC:
  103                 return &enc_xform_des;
  104         case SADB_EALG_3DESCBC:
  105                 return &enc_xform_3des;
  106         case SADB_X_EALG_AES:
  107                 return &enc_xform_rijndael128;
  108         case SADB_X_EALG_BLOWFISHCBC:
  109                 return &enc_xform_blf;
  110         case SADB_X_EALG_CAST128CBC:
  111                 return &enc_xform_cast5;
  112         case SADB_X_EALG_SKIPJACK:
  113                 return &enc_xform_skipjack;
  114         case SADB_EALG_NULL:
  115                 return &enc_xform_null;
  116         }
  117         return NULL;
  118 }
  119 
  120 size_t
  121 esp_hdrsiz(struct secasvar *sav)
  122 {
  123         size_t size;
  124 
  125         if (sav != NULL) {
  126                 /*XXX not right for null algorithm--does it matter??*/
  127                 IPSEC_ASSERT(sav->tdb_encalgxform != NULL,
  128                         ("SA with null xform"));
  129                 if (sav->flags & SADB_X_EXT_OLD)
  130                         size = sizeof (struct esp);
  131                 else
  132                         size = sizeof (struct newesp);
  133                 size += sav->tdb_encalgxform->blocksize + 9;
  134                 /*XXX need alg check???*/
  135                 if (sav->tdb_authalgxform != NULL && sav->replay)
  136                         size += ah_hdrsiz(sav);
  137         } else {
  138                 /*
  139                  *   base header size
  140                  * + max iv length for CBC mode
  141                  * + max pad length
  142                  * + sizeof (pad length field)
  143                  * + sizeof (next header field)
  144                  * + max icv supported.
  145                  */
  146                 size = sizeof (struct newesp) + esp_max_ivlen + 9 + 16;
  147         }
  148         return size;
  149 }
  150 
  151 /*
  152  * esp_init() is called when an SPI is being set up.
  153  */
  154 static int
  155 esp_init(struct secasvar *sav, struct xformsw *xsp)
  156 {
  157         struct enc_xform *txform;
  158         struct cryptoini cria, crie;
  159         int keylen;
  160         int error;
  161 
  162         txform = esp_algorithm_lookup(sav->alg_enc);
  163         if (txform == NULL) {
  164                 DPRINTF(("%s: unsupported encryption algorithm %d\n",
  165                         __func__, sav->alg_enc));
  166                 return EINVAL;
  167         }
  168         if (sav->key_enc == NULL) {
  169                 DPRINTF(("%s: no encoding key for %s algorithm\n",
  170                          __func__, txform->name));
  171                 return EINVAL;
  172         }
  173         if ((sav->flags&(SADB_X_EXT_OLD|SADB_X_EXT_IV4B)) == SADB_X_EXT_IV4B) {
  174                 DPRINTF(("%s: 4-byte IV not supported with protocol\n",
  175                         __func__));
  176                 return EINVAL;
  177         }
  178         keylen = _KEYLEN(sav->key_enc);
  179         if (txform->minkey > keylen || keylen > txform->maxkey) {
  180                 DPRINTF(("%s: invalid key length %u, must be in the range "
  181                         "[%u..%u] for algorithm %s\n", __func__,
  182                         keylen, txform->minkey, txform->maxkey,
  183                         txform->name));
  184                 return EINVAL;
  185         }
  186 
  187         /*
  188          * NB: The null xform needs a non-zero blocksize to keep the
  189          *      crypto code happy but if we use it to set ivlen then
  190          *      the ESP header will be processed incorrectly.  The
  191          *      compromise is to force it to zero here.
  192          */
  193         sav->ivlen = (txform == &enc_xform_null ? 0 : txform->blocksize);
  194         sav->iv = (caddr_t) malloc(sav->ivlen, M_XDATA, M_WAITOK);
  195         if (sav->iv == NULL) {
  196                 DPRINTF(("%s: no memory for IV\n", __func__));
  197                 return EINVAL;
  198         }
  199         key_randomfill(sav->iv, sav->ivlen);    /*XXX*/
  200 
  201         /*
  202          * Setup AH-related state.
  203          */
  204         if (sav->alg_auth != 0) {
  205                 error = ah_init0(sav, xsp, &cria);
  206                 if (error)
  207                         return error;
  208         }
  209 
  210         /* NB: override anything set in ah_init0 */
  211         sav->tdb_xform = xsp;
  212         sav->tdb_encalgxform = txform;
  213 
  214         /* Initialize crypto session. */
  215         bzero(&crie, sizeof (crie));
  216         crie.cri_alg = sav->tdb_encalgxform->type;
  217         crie.cri_klen = _KEYBITS(sav->key_enc);
  218         crie.cri_key = _KEYBUF(sav->key_enc);
  219         /* XXX Rounds ? */
  220 
  221         if (sav->tdb_authalgxform && sav->tdb_encalgxform) {
  222                 /* init both auth & enc */
  223                 crie.cri_next = &cria;
  224                 error = crypto_newsession(&sav->tdb_cryptoid,
  225                                           &crie, crypto_support);
  226         } else if (sav->tdb_encalgxform) {
  227                 error = crypto_newsession(&sav->tdb_cryptoid,
  228                                           &crie, crypto_support);
  229         } else if (sav->tdb_authalgxform) {
  230                 error = crypto_newsession(&sav->tdb_cryptoid,
  231                                           &cria, crypto_support);
  232         } else {
  233                 /* XXX cannot happen? */
  234                 DPRINTF(("%s: no encoding OR authentication xform!\n",
  235                         __func__));
  236                 error = EINVAL;
  237         }
  238         return error;
  239 }
  240 
  241 /*
  242  * Paranoia.
  243  */
  244 static int
  245 esp_zeroize(struct secasvar *sav)
  246 {
  247         /* NB: ah_zerorize free's the crypto session state */
  248         int error = ah_zeroize(sav);
  249 
  250         if (sav->key_enc)
  251                 bzero(_KEYBUF(sav->key_enc), _KEYLEN(sav->key_enc));
  252         if (sav->iv) {
  253                 free(sav->iv, M_XDATA);
  254                 sav->iv = NULL;
  255         }
  256         sav->tdb_encalgxform = NULL;
  257         sav->tdb_xform = NULL;
  258         return error;
  259 }
  260 
  261 /*
  262  * ESP input processing, called (eventually) through the protocol switch.
  263  */
  264 static int
  265 esp_input(struct mbuf *m, struct secasvar *sav, int skip, int protoff)
  266 {
  267         struct auth_hash *esph;
  268         struct enc_xform *espx;
  269         struct tdb_ident *tdbi;
  270         struct tdb_crypto *tc;
  271         int plen, alen, hlen;
  272         struct m_tag *mtag;
  273         struct newesp *esp;
  274 
  275         struct cryptodesc *crde;
  276         struct cryptop *crp;
  277 
  278         IPSEC_SPLASSERT_SOFTNET(__func__);
  279 
  280         IPSEC_ASSERT(sav != NULL, ("null SA"));
  281         IPSEC_ASSERT(sav->tdb_encalgxform != NULL, ("null encoding xform"));
  282         IPSEC_ASSERT((skip&3) == 0 && (m->m_pkthdr.len&3) == 0,
  283                 ("misaligned packet, skip %u pkt len %u",
  284                         skip, m->m_pkthdr.len));
  285 
  286         /* XXX don't pullup, just copy header */
  287         IP6_EXTHDR_GET(esp, struct newesp *, m, skip, sizeof (struct newesp));
  288 
  289         esph = sav->tdb_authalgxform;
  290         espx = sav->tdb_encalgxform;
  291 
  292         /* Determine the ESP header length */
  293         if (sav->flags & SADB_X_EXT_OLD)
  294                 hlen = sizeof (struct esp) + sav->ivlen;
  295         else
  296                 hlen = sizeof (struct newesp) + sav->ivlen;
  297         /* Authenticator hash size */
  298         alen = esph ? AH_HMAC_HASHLEN : 0;
  299 
  300         /*
  301          * Verify payload length is multiple of encryption algorithm
  302          * block size.
  303          *
  304          * NB: This works for the null algorithm because the blocksize
  305          *     is 4 and all packets must be 4-byte aligned regardless
  306          *     of the algorithm.
  307          */
  308         plen = m->m_pkthdr.len - (skip + hlen + alen);
  309         if ((plen & (espx->blocksize - 1)) || (plen <= 0)) {
  310                 DPRINTF(("%s: payload of %d octets not a multiple of %d octets,"
  311                     "  SA %s/%08lx\n", __func__,
  312                     plen, espx->blocksize,
  313                     ipsec_address(&sav->sah->saidx.dst),
  314                     (u_long) ntohl(sav->spi)));
  315                 espstat.esps_badilen++;
  316                 m_freem(m);
  317                 return EINVAL;
  318         }
  319 
  320         /*
  321          * Check sequence number.
  322          */
  323         if (esph && sav->replay && !ipsec_chkreplay(ntohl(esp->esp_seq), sav)) {
  324                 DPRINTF(("%s: packet replay check for %s\n", __func__,
  325                     ipsec_logsastr(sav)));      /*XXX*/
  326                 espstat.esps_replay++;
  327                 m_freem(m);
  328                 return ENOBUFS;         /*XXX*/
  329         }
  330 
  331         /* Update the counters */
  332         espstat.esps_ibytes += m->m_pkthdr.len - skip - hlen - alen;
  333 
  334         /* Find out if we've already done crypto */
  335         for (mtag = m_tag_find(m, PACKET_TAG_IPSEC_IN_CRYPTO_DONE, NULL);
  336              mtag != NULL;
  337              mtag = m_tag_find(m, PACKET_TAG_IPSEC_IN_CRYPTO_DONE, mtag)) {
  338                 tdbi = (struct tdb_ident *) (mtag + 1);
  339                 if (tdbi->proto == sav->sah->saidx.proto &&
  340                     tdbi->spi == sav->spi &&
  341                     !bcmp(&tdbi->dst, &sav->sah->saidx.dst,
  342                           sizeof(union sockaddr_union)))
  343                         break;
  344         }
  345 
  346         /* Get crypto descriptors */
  347         crp = crypto_getreq(esph && espx ? 2 : 1);
  348         if (crp == NULL) {
  349                 DPRINTF(("%s: failed to acquire crypto descriptors\n",
  350                         __func__));
  351                 espstat.esps_crypto++;
  352                 m_freem(m);
  353                 return ENOBUFS;
  354         }
  355 
  356         /* Get IPsec-specific opaque pointer */
  357         if (esph == NULL || mtag != NULL)
  358                 tc = (struct tdb_crypto *) malloc(sizeof(struct tdb_crypto),
  359                     M_XDATA, M_NOWAIT|M_ZERO);
  360         else
  361                 tc = (struct tdb_crypto *) malloc(sizeof(struct tdb_crypto) + alen,
  362                     M_XDATA, M_NOWAIT|M_ZERO);
  363         if (tc == NULL) {
  364                 crypto_freereq(crp);
  365                 DPRINTF(("%s: failed to allocate tdb_crypto\n", __func__));
  366                 espstat.esps_crypto++;
  367                 m_freem(m);
  368                 return ENOBUFS;
  369         }
  370 
  371         tc->tc_ptr = (caddr_t) mtag;
  372 
  373         if (esph) {
  374                 struct cryptodesc *crda = crp->crp_desc;
  375 
  376                 IPSEC_ASSERT(crda != NULL, ("null ah crypto descriptor"));
  377 
  378                 /* Authentication descriptor */
  379                 crda->crd_skip = skip;
  380                 crda->crd_len = m->m_pkthdr.len - (skip + alen);
  381                 crda->crd_inject = m->m_pkthdr.len - alen;
  382 
  383                 crda->crd_alg = esph->type;
  384                 crda->crd_key = _KEYBUF(sav->key_auth);
  385                 crda->crd_klen = _KEYBITS(sav->key_auth);
  386 
  387                 /* Copy the authenticator */
  388                 if (mtag == NULL)
  389                         m_copydata(m, m->m_pkthdr.len - alen, alen,
  390                                    (caddr_t) (tc + 1));
  391 
  392                 /* Chain authentication request */
  393                 crde = crda->crd_next;
  394         } else {
  395                 crde = crp->crp_desc;
  396         }
  397 
  398         /* Crypto operation descriptor */
  399         crp->crp_ilen = m->m_pkthdr.len; /* Total input length */
  400         crp->crp_flags = CRYPTO_F_IMBUF | CRYPTO_F_CBIFSYNC;
  401         crp->crp_buf = (caddr_t) m;
  402         crp->crp_callback = esp_input_cb;
  403         crp->crp_sid = sav->tdb_cryptoid;
  404         crp->crp_opaque = (caddr_t) tc;
  405 
  406         /* These are passed as-is to the callback */
  407         tc->tc_spi = sav->spi;
  408         tc->tc_dst = sav->sah->saidx.dst;
  409         tc->tc_proto = sav->sah->saidx.proto;
  410         tc->tc_protoff = protoff;
  411         tc->tc_skip = skip;
  412 
  413         /* Decryption descriptor */
  414         if (espx) {
  415                 IPSEC_ASSERT(crde != NULL, ("null esp crypto descriptor"));
  416                 crde->crd_skip = skip + hlen;
  417                 crde->crd_len = m->m_pkthdr.len - (skip + hlen + alen);
  418                 crde->crd_inject = skip + hlen - sav->ivlen;
  419 
  420                 crde->crd_alg = espx->type;
  421                 crde->crd_key = _KEYBUF(sav->key_enc);
  422                 crde->crd_klen = _KEYBITS(sav->key_enc);
  423                 /* XXX Rounds ? */
  424         }
  425 
  426         if (mtag == NULL)
  427                 return crypto_dispatch(crp);
  428         else
  429                 return esp_input_cb(crp);
  430 }
  431 
  432 #ifdef INET6
  433 #define IPSEC_COMMON_INPUT_CB(m, sav, skip, protoff, mtag) do {              \
  434         if (saidx->dst.sa.sa_family == AF_INET6) {                           \
  435                 error = ipsec6_common_input_cb(m, sav, skip, protoff, mtag); \
  436         } else {                                                             \
  437                 error = ipsec4_common_input_cb(m, sav, skip, protoff, mtag); \
  438         }                                                                    \
  439 } while (0)
  440 #else
  441 #define IPSEC_COMMON_INPUT_CB(m, sav, skip, protoff, mtag)                   \
  442         (error = ipsec4_common_input_cb(m, sav, skip, protoff, mtag))
  443 #endif
  444 
  445 /*
  446  * ESP input callback from the crypto driver.
  447  */
  448 static int
  449 esp_input_cb(struct cryptop *crp)
  450 {
  451         u_int8_t lastthree[3], aalg[AH_HMAC_HASHLEN];
  452         int hlen, skip, protoff, error;
  453         struct mbuf *m;
  454         struct cryptodesc *crd;
  455         struct auth_hash *esph;
  456         struct enc_xform *espx;
  457         struct tdb_crypto *tc;
  458         struct m_tag *mtag;
  459         struct secasvar *sav;
  460         struct secasindex *saidx;
  461         caddr_t ptr;
  462 
  463         crd = crp->crp_desc;
  464         IPSEC_ASSERT(crd != NULL, ("null crypto descriptor!"));
  465 
  466         tc = (struct tdb_crypto *) crp->crp_opaque;
  467         IPSEC_ASSERT(tc != NULL, ("null opaque crypto data area!"));
  468         skip = tc->tc_skip;
  469         protoff = tc->tc_protoff;
  470         mtag = (struct m_tag *) tc->tc_ptr;
  471         m = (struct mbuf *) crp->crp_buf;
  472 
  473         sav = KEY_ALLOCSA(&tc->tc_dst, tc->tc_proto, tc->tc_spi);
  474         if (sav == NULL) {
  475                 espstat.esps_notdb++;
  476                 DPRINTF(("%s: SA gone during crypto (SA %s/%08lx proto %u)\n",
  477                     __func__, ipsec_address(&tc->tc_dst),
  478                     (u_long) ntohl(tc->tc_spi), tc->tc_proto));
  479                 error = ENOBUFS;                /*XXX*/
  480                 goto bad;
  481         }
  482 
  483         saidx = &sav->sah->saidx;
  484         IPSEC_ASSERT(saidx->dst.sa.sa_family == AF_INET ||
  485                 saidx->dst.sa.sa_family == AF_INET6,
  486                 ("unexpected protocol family %u", saidx->dst.sa.sa_family));
  487 
  488         esph = sav->tdb_authalgxform;
  489         espx = sav->tdb_encalgxform;
  490 
  491         /* Check for crypto errors */
  492         if (crp->crp_etype) {
  493                 /* Reset the session ID */
  494                 if (sav->tdb_cryptoid != 0)
  495                         sav->tdb_cryptoid = crp->crp_sid;
  496 
  497                 if (crp->crp_etype == EAGAIN) {
  498                         KEY_FREESAV(&sav);
  499                         return crypto_dispatch(crp);
  500                 }
  501 
  502                 espstat.esps_noxform++;
  503                 DPRINTF(("%s: crypto error %d\n", __func__, crp->crp_etype));
  504                 error = crp->crp_etype;
  505                 goto bad;
  506         }
  507 
  508         /* Shouldn't happen... */
  509         if (m == NULL) {
  510                 espstat.esps_crypto++;
  511                 DPRINTF(("%s: bogus returned buffer from crypto\n", __func__));
  512                 error = EINVAL;
  513                 goto bad;
  514         }
  515         espstat.esps_hist[sav->alg_enc]++;
  516 
  517         /* If authentication was performed, check now. */
  518         if (esph != NULL) {
  519                 /*
  520                  * If we have a tag, it means an IPsec-aware NIC did
  521                  * the verification for us.  Otherwise we need to
  522                  * check the authentication calculation.
  523                  */
  524                 ahstat.ahs_hist[sav->alg_auth]++;
  525                 if (mtag == NULL) {
  526                         /* Copy the authenticator from the packet */
  527                         m_copydata(m, m->m_pkthdr.len - esph->authsize,
  528                                 esph->authsize, aalg);
  529 
  530                         ptr = (caddr_t) (tc + 1);
  531 
  532                         /* Verify authenticator */
  533                         if (bcmp(ptr, aalg, esph->authsize) != 0) {
  534                                 DPRINTF(("%s: "
  535                     "authentication hash mismatch for packet in SA %s/%08lx\n",
  536                                     __func__,
  537                                     ipsec_address(&saidx->dst),
  538                                     (u_long) ntohl(sav->spi)));
  539                                 espstat.esps_badauth++;
  540                                 error = EACCES;
  541                                 goto bad;
  542                         }
  543                 }
  544 
  545                 /* Remove trailing authenticator */
  546                 m_adj(m, -(esph->authsize));
  547         }
  548 
  549         /* Release the crypto descriptors */
  550         free(tc, M_XDATA), tc = NULL;
  551         crypto_freereq(crp), crp = NULL;
  552 
  553         /*
  554          * Packet is now decrypted.
  555          */
  556         m->m_flags |= M_DECRYPTED;
  557 
  558         /*
  559          * Update replay sequence number, if appropriate.
  560          */
  561         if (sav->replay) {
  562                 u_int32_t seq;
  563 
  564                 m_copydata(m, skip + offsetof(struct newesp, esp_seq),
  565                            sizeof (seq), (caddr_t) &seq);
  566                 if (ipsec_updatereplay(ntohl(seq), sav)) {
  567                         DPRINTF(("%s: packet replay check for %s\n", __func__,
  568                             ipsec_logsastr(sav)));
  569                         espstat.esps_replay++;
  570                         error = ENOBUFS;
  571                         goto bad;
  572                 }
  573         }
  574 
  575         /* Determine the ESP header length */
  576         if (sav->flags & SADB_X_EXT_OLD)
  577                 hlen = sizeof (struct esp) + sav->ivlen;
  578         else
  579                 hlen = sizeof (struct newesp) + sav->ivlen;
  580 
  581         /* Remove the ESP header and IV from the mbuf. */
  582         error = m_striphdr(m, skip, hlen);
  583         if (error) {
  584                 espstat.esps_hdrops++;
  585                 DPRINTF(("%s: bad mbuf chain, SA %s/%08lx\n", __func__,
  586                     ipsec_address(&sav->sah->saidx.dst),
  587                     (u_long) ntohl(sav->spi)));
  588                 goto bad;
  589         }
  590 
  591         /* Save the last three bytes of decrypted data */
  592         m_copydata(m, m->m_pkthdr.len - 3, 3, lastthree);
  593 
  594         /* Verify pad length */
  595         if (lastthree[1] + 2 > m->m_pkthdr.len - skip) {
  596                 espstat.esps_badilen++;
  597                 DPRINTF(("%s: invalid padding length %d for %u byte packet "
  598                         "in SA %s/%08lx\n", __func__,
  599                          lastthree[1], m->m_pkthdr.len - skip,
  600                          ipsec_address(&sav->sah->saidx.dst),
  601                          (u_long) ntohl(sav->spi)));
  602                 error = EINVAL;
  603                 goto bad;
  604         }
  605 
  606         /* Verify correct decryption by checking the last padding bytes */
  607         if ((sav->flags & SADB_X_EXT_PMASK) != SADB_X_EXT_PRAND) {
  608                 if (lastthree[1] != lastthree[0] && lastthree[1] != 0) {
  609                         espstat.esps_badenc++;
  610                         DPRINTF(("%s: decryption failed for packet in "
  611                                 "SA %s/%08lx\n", __func__,
  612                                 ipsec_address(&sav->sah->saidx.dst),
  613                                 (u_long) ntohl(sav->spi)));
  614                         error = EINVAL;
  615                         goto bad;
  616                 }
  617         }
  618 
  619         /* Trim the mbuf chain to remove trailing authenticator and padding */
  620         m_adj(m, -(lastthree[1] + 2));
  621 
  622         /* Restore the Next Protocol field */
  623         m_copyback(m, protoff, sizeof (u_int8_t), lastthree + 2);
  624 
  625         IPSEC_COMMON_INPUT_CB(m, sav, skip, protoff, mtag);
  626 
  627         KEY_FREESAV(&sav);
  628         return error;
  629 bad:
  630         if (sav)
  631                 KEY_FREESAV(&sav);
  632         if (m != NULL)
  633                 m_freem(m);
  634         if (tc != NULL)
  635                 free(tc, M_XDATA);
  636         if (crp != NULL)
  637                 crypto_freereq(crp);
  638         return error;
  639 }
  640 
  641 /*
  642  * ESP output routine, called by ipsec[46]_process_packet().
  643  */
  644 static int
  645 esp_output(
  646         struct mbuf *m,
  647         struct ipsecrequest *isr,
  648         struct mbuf **mp,
  649         int skip,
  650         int protoff
  651 )
  652 {
  653         struct enc_xform *espx;
  654         struct auth_hash *esph;
  655         int hlen, rlen, plen, padding, blks, alen, i, roff;
  656         struct mbuf *mo = (struct mbuf *) NULL;
  657         struct tdb_crypto *tc;
  658         struct secasvar *sav;
  659         struct secasindex *saidx;
  660         unsigned char *pad;
  661         u_int8_t prot;
  662         int error, maxpacketsize;
  663 
  664         struct cryptodesc *crde = NULL, *crda = NULL;
  665         struct cryptop *crp;
  666 
  667         IPSEC_SPLASSERT_SOFTNET(__func__);
  668 
  669         sav = isr->sav;
  670         IPSEC_ASSERT(sav != NULL, ("null SA"));
  671         esph = sav->tdb_authalgxform;
  672         espx = sav->tdb_encalgxform;
  673         IPSEC_ASSERT(espx != NULL, ("null encoding xform"));
  674 
  675         if (sav->flags & SADB_X_EXT_OLD)
  676                 hlen = sizeof (struct esp) + sav->ivlen;
  677         else
  678                 hlen = sizeof (struct newesp) + sav->ivlen;
  679 
  680         rlen = m->m_pkthdr.len - skip;  /* Raw payload length. */
  681         /*
  682          * NB: The null encoding transform has a blocksize of 4
  683          *     so that headers are properly aligned.
  684          */
  685         blks = espx->blocksize;         /* IV blocksize */
  686 
  687         /* XXX clamp padding length a la KAME??? */
  688         padding = ((blks - ((rlen + 2) % blks)) % blks) + 2;
  689         plen = rlen + padding;          /* Padded payload length. */
  690 
  691         if (esph)
  692                 alen = AH_HMAC_HASHLEN;
  693         else
  694                 alen = 0;
  695 
  696         espstat.esps_output++;
  697 
  698         saidx = &sav->sah->saidx;
  699         /* Check for maximum packet size violations. */
  700         switch (saidx->dst.sa.sa_family) {
  701 #ifdef INET
  702         case AF_INET:
  703                 maxpacketsize = IP_MAXPACKET;
  704                 break;
  705 #endif /* INET */
  706 #ifdef INET6
  707         case AF_INET6:
  708                 maxpacketsize = IPV6_MAXPACKET;
  709                 break;
  710 #endif /* INET6 */
  711         default:
  712                 DPRINTF(("%s: unknown/unsupported protocol "
  713                     "family %d, SA %s/%08lx\n", __func__,
  714                     saidx->dst.sa.sa_family, ipsec_address(&saidx->dst),
  715                     (u_long) ntohl(sav->spi)));
  716                 espstat.esps_nopf++;
  717                 error = EPFNOSUPPORT;
  718                 goto bad;
  719         }
  720         if (skip + hlen + rlen + padding + alen > maxpacketsize) {
  721                 DPRINTF(("%s: packet in SA %s/%08lx got too big "
  722                     "(len %u, max len %u)\n", __func__,
  723                     ipsec_address(&saidx->dst), (u_long) ntohl(sav->spi),
  724                     skip + hlen + rlen + padding + alen, maxpacketsize));
  725                 espstat.esps_toobig++;
  726                 error = EMSGSIZE;
  727                 goto bad;
  728         }
  729 
  730         /* Update the counters. */
  731         espstat.esps_obytes += m->m_pkthdr.len - skip;
  732 
  733         m = m_clone(m);
  734         if (m == NULL) {
  735                 DPRINTF(("%s: cannot clone mbuf chain, SA %s/%08lx\n", __func__,
  736                     ipsec_address(&saidx->dst), (u_long) ntohl(sav->spi)));
  737                 espstat.esps_hdrops++;
  738                 error = ENOBUFS;
  739                 goto bad;
  740         }
  741 
  742         /* Inject ESP header. */
  743         mo = m_makespace(m, skip, hlen, &roff);
  744         if (mo == NULL) {
  745                 DPRINTF(("%s: %u byte ESP hdr inject failed for SA %s/%08lx\n",
  746                     __func__, hlen, ipsec_address(&saidx->dst),
  747                     (u_long) ntohl(sav->spi)));
  748                 espstat.esps_hdrops++;          /* XXX diffs from openbsd */
  749                 error = ENOBUFS;
  750                 goto bad;
  751         }
  752 
  753         /* Initialize ESP header. */
  754         bcopy((caddr_t) &sav->spi, mtod(mo, caddr_t) + roff, sizeof(u_int32_t));
  755         if (sav->replay) {
  756                 u_int32_t replay = htonl(++(sav->replay->count));
  757                 bcopy((caddr_t) &replay,
  758                     mtod(mo, caddr_t) + roff + sizeof(u_int32_t),
  759                     sizeof(u_int32_t));
  760         }
  761 
  762         /*
  763          * Add padding -- better to do it ourselves than use the crypto engine,
  764          * although if/when we support compression, we'd have to do that.
  765          */
  766         pad = (u_char *) m_pad(m, padding + alen);
  767         if (pad == NULL) {
  768                 DPRINTF(("%s: m_pad failed for SA %s/%08lx\n", __func__,
  769                     ipsec_address(&saidx->dst), (u_long) ntohl(sav->spi)));
  770                 m = NULL;               /* NB: free'd by m_pad */
  771                 error = ENOBUFS;
  772                 goto bad;
  773         }
  774 
  775         /*
  776          * Add padding: random, zero, or self-describing.
  777          * XXX catch unexpected setting
  778          */
  779         switch (sav->flags & SADB_X_EXT_PMASK) {
  780         case SADB_X_EXT_PRAND:
  781                 (void) read_random(pad, padding - 2);
  782                 break;
  783         case SADB_X_EXT_PZERO:
  784                 bzero(pad, padding - 2);
  785                 break;
  786         case SADB_X_EXT_PSEQ:
  787                 for (i = 0; i < padding - 2; i++)
  788                         pad[i] = i+1;
  789                 break;
  790         }
  791 
  792         /* Fix padding length and Next Protocol in padding itself. */
  793         pad[padding - 2] = padding - 2;
  794         m_copydata(m, protoff, sizeof(u_int8_t), pad + padding - 1);
  795 
  796         /* Fix Next Protocol in IPv4/IPv6 header. */
  797         prot = IPPROTO_ESP;
  798         m_copyback(m, protoff, sizeof(u_int8_t), (u_char *) &prot);
  799 
  800         /* Get crypto descriptors. */
  801         crp = crypto_getreq(esph && espx ? 2 : 1);
  802         if (crp == NULL) {
  803                 DPRINTF(("%s: failed to acquire crypto descriptors\n",
  804                         __func__));
  805                 espstat.esps_crypto++;
  806                 error = ENOBUFS;
  807                 goto bad;
  808         }
  809 
  810         if (espx) {
  811                 crde = crp->crp_desc;
  812                 crda = crde->crd_next;
  813 
  814                 /* Encryption descriptor. */
  815                 crde->crd_skip = skip + hlen;
  816                 crde->crd_len = m->m_pkthdr.len - (skip + hlen + alen);
  817                 crde->crd_flags = CRD_F_ENCRYPT;
  818                 crde->crd_inject = skip + hlen - sav->ivlen;
  819 
  820                 /* Encryption operation. */
  821                 crde->crd_alg = espx->type;
  822                 crde->crd_key = _KEYBUF(sav->key_enc);
  823                 crde->crd_klen = _KEYBITS(sav->key_enc);
  824                 /* XXX Rounds ? */
  825         } else
  826                 crda = crp->crp_desc;
  827 
  828         /* IPsec-specific opaque crypto info. */
  829         tc = (struct tdb_crypto *) malloc(sizeof(struct tdb_crypto),
  830                 M_XDATA, M_NOWAIT|M_ZERO);
  831         if (tc == NULL) {
  832                 crypto_freereq(crp);
  833                 DPRINTF(("%s: failed to allocate tdb_crypto\n", __func__));
  834                 espstat.esps_crypto++;
  835                 error = ENOBUFS;
  836                 goto bad;
  837         }
  838 
  839         /* Callback parameters */
  840         tc->tc_isr = isr;
  841         tc->tc_spi = sav->spi;
  842         tc->tc_dst = saidx->dst;
  843         tc->tc_proto = saidx->proto;
  844 
  845         /* Crypto operation descriptor. */
  846         crp->crp_ilen = m->m_pkthdr.len; /* Total input length. */
  847         crp->crp_flags = CRYPTO_F_IMBUF | CRYPTO_F_CBIFSYNC;
  848         crp->crp_buf = (caddr_t) m;
  849         crp->crp_callback = esp_output_cb;
  850         crp->crp_opaque = (caddr_t) tc;
  851         crp->crp_sid = sav->tdb_cryptoid;
  852 
  853         if (esph) {
  854                 /* Authentication descriptor. */
  855                 crda->crd_skip = skip;
  856                 crda->crd_len = m->m_pkthdr.len - (skip + alen);
  857                 crda->crd_inject = m->m_pkthdr.len - alen;
  858 
  859                 /* Authentication operation. */
  860                 crda->crd_alg = esph->type;
  861                 crda->crd_key = _KEYBUF(sav->key_auth);
  862                 crda->crd_klen = _KEYBITS(sav->key_auth);
  863         }
  864 
  865         return crypto_dispatch(crp);
  866 bad:
  867         if (m)
  868                 m_freem(m);
  869         return (error);
  870 }
  871 
  872 /*
  873  * ESP output callback from the crypto driver.
  874  */
  875 static int
  876 esp_output_cb(struct cryptop *crp)
  877 {
  878         struct tdb_crypto *tc;
  879         struct ipsecrequest *isr;
  880         struct secasvar *sav;
  881         struct mbuf *m;
  882         int err, error;
  883 
  884         tc = (struct tdb_crypto *) crp->crp_opaque;
  885         IPSEC_ASSERT(tc != NULL, ("null opaque data area!"));
  886         m = (struct mbuf *) crp->crp_buf;
  887 
  888         isr = tc->tc_isr;
  889         IPSECREQUEST_LOCK(isr);
  890         sav = KEY_ALLOCSA(&tc->tc_dst, tc->tc_proto, tc->tc_spi);
  891         if (sav == NULL) {
  892                 espstat.esps_notdb++;
  893                 DPRINTF(("%s: SA gone during crypto (SA %s/%08lx proto %u)\n",
  894                     __func__, ipsec_address(&tc->tc_dst),
  895                     (u_long) ntohl(tc->tc_spi), tc->tc_proto));
  896                 error = ENOBUFS;                /*XXX*/
  897                 goto bad;
  898         }
  899         IPSEC_ASSERT(isr->sav == sav,
  900                 ("SA changed was %p now %p\n", isr->sav, sav));
  901 
  902         /* Check for crypto errors. */
  903         if (crp->crp_etype) {
  904                 /* Reset session ID. */
  905                 if (sav->tdb_cryptoid != 0)
  906                         sav->tdb_cryptoid = crp->crp_sid;
  907 
  908                 if (crp->crp_etype == EAGAIN) {
  909                         KEY_FREESAV(&sav);
  910                         IPSECREQUEST_UNLOCK(isr);
  911                         return crypto_dispatch(crp);
  912                 }
  913 
  914                 espstat.esps_noxform++;
  915                 DPRINTF(("%s: crypto error %d\n", __func__, crp->crp_etype));
  916                 error = crp->crp_etype;
  917                 goto bad;
  918         }
  919 
  920         /* Shouldn't happen... */
  921         if (m == NULL) {
  922                 espstat.esps_crypto++;
  923                 DPRINTF(("%s: bogus returned buffer from crypto\n", __func__));
  924                 error = EINVAL;
  925                 goto bad;
  926         }
  927         espstat.esps_hist[sav->alg_enc]++;
  928         if (sav->tdb_authalgxform != NULL)
  929                 ahstat.ahs_hist[sav->alg_auth]++;
  930 
  931         /* Release crypto descriptors. */
  932         free(tc, M_XDATA);
  933         crypto_freereq(crp);
  934 
  935         /* NB: m is reclaimed by ipsec_process_done. */
  936         err = ipsec_process_done(m, isr);
  937         KEY_FREESAV(&sav);
  938         IPSECREQUEST_UNLOCK(isr);
  939 
  940         return err;
  941 bad:
  942         if (sav)
  943                 KEY_FREESAV(&sav);
  944         IPSECREQUEST_UNLOCK(isr);
  945         if (m)
  946                 m_freem(m);
  947         free(tc, M_XDATA);
  948         crypto_freereq(crp);
  949         return error;
  950 }
  951 
  952 static struct xformsw esp_xformsw = {
  953         XF_ESP,         XFT_CONF|XFT_AUTH,      "IPsec ESP",
  954         esp_init,       esp_zeroize,            esp_input,
  955         esp_output
  956 };
  957 
  958 static void
  959 esp_attach(void)
  960 {
  961 #define MAXIV(xform)                                    \
  962         if (xform.blocksize > esp_max_ivlen)            \
  963                 esp_max_ivlen = xform.blocksize         \
  964 
  965         esp_max_ivlen = 0;
  966         MAXIV(enc_xform_des);           /* SADB_EALG_DESCBC */
  967         MAXIV(enc_xform_3des);          /* SADB_EALG_3DESCBC */
  968         MAXIV(enc_xform_rijndael128);   /* SADB_X_EALG_AES */
  969         MAXIV(enc_xform_blf);           /* SADB_X_EALG_BLOWFISHCBC */
  970         MAXIV(enc_xform_cast5);         /* SADB_X_EALG_CAST128CBC */
  971         MAXIV(enc_xform_skipjack);      /* SADB_X_EALG_SKIPJACK */
  972         MAXIV(enc_xform_null);          /* SADB_EALG_NULL */
  973 
  974         xform_register(&esp_xformsw);
  975 #undef MAXIV
  976 }
  977 SYSINIT(esp_xform_init, SI_SUB_PROTO_DOMAIN, SI_ORDER_MIDDLE, esp_attach, NULL);

Cache object: 70675e81cdd3089f5f1688d94632ec14


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