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: stable/9/sys/netipsec/xform_esp.c 252693 2013-07-04 08:59:34Z ae $    */
    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 #include <net/vnet.h>
   52 
   53 #include <netinet/in.h>
   54 #include <netinet/in_systm.h>
   55 #include <netinet/ip.h>
   56 #include <netinet/ip_ecn.h>
   57 #include <netinet/ip6.h>
   58 
   59 #include <net/route.h>
   60 #include <netipsec/ipsec.h>
   61 #include <netipsec/ah.h>
   62 #include <netipsec/ah_var.h>
   63 #include <netipsec/esp.h>
   64 #include <netipsec/esp_var.h>
   65 #include <netipsec/xform.h>
   66 
   67 #ifdef INET6
   68 #include <netinet6/ip6_var.h>
   69 #include <netipsec/ipsec6.h>
   70 #include <netinet6/ip6_ecn.h>
   71 #endif
   72 
   73 #include <netipsec/key.h>
   74 #include <netipsec/key_debug.h>
   75 
   76 #include <opencrypto/cryptodev.h>
   77 #include <opencrypto/xform.h>
   78 
   79 VNET_DEFINE(int, esp_enable) = 1;
   80 VNET_DEFINE(struct espstat, espstat);
   81 
   82 SYSCTL_DECL(_net_inet_esp);
   83 SYSCTL_VNET_INT(_net_inet_esp, OID_AUTO,
   84         esp_enable,     CTLFLAG_RW,     &VNET_NAME(esp_enable), 0, "");
   85 SYSCTL_VNET_STRUCT(_net_inet_esp, IPSECCTL_STATS,
   86         stats,          CTLFLAG_RD,     &VNET_NAME(espstat),    espstat, "");
   87 
   88 static VNET_DEFINE(int, esp_max_ivlen); /* max iv length over all algorithms */
   89 #define V_esp_max_ivlen VNET(esp_max_ivlen)
   90 
   91 static int esp_input_cb(struct cryptop *op);
   92 static int esp_output_cb(struct cryptop *crp);
   93 
   94 /*
   95  * NB: this is public for use by the PF_KEY support.
   96  * NB: if you add support here; be sure to add code to esp_attach below!
   97  */
   98 struct enc_xform *
   99 esp_algorithm_lookup(int alg)
  100 {
  101         if (alg >= ESP_ALG_MAX)
  102                 return NULL;
  103         switch (alg) {
  104         case SADB_EALG_DESCBC:
  105                 return &enc_xform_des;
  106         case SADB_EALG_3DESCBC:
  107                 return &enc_xform_3des;
  108         case SADB_X_EALG_AES:
  109                 return &enc_xform_rijndael128;
  110         case SADB_X_EALG_BLOWFISHCBC:
  111                 return &enc_xform_blf;
  112         case SADB_X_EALG_CAST128CBC:
  113                 return &enc_xform_cast5;
  114         case SADB_X_EALG_SKIPJACK:
  115                 return &enc_xform_skipjack;
  116         case SADB_EALG_NULL:
  117                 return &enc_xform_null;
  118         case SADB_X_EALG_CAMELLIACBC:
  119                 return &enc_xform_camellia;
  120         }
  121         return NULL;
  122 }
  123 
  124 size_t
  125 esp_hdrsiz(struct secasvar *sav)
  126 {
  127         size_t size;
  128 
  129         if (sav != NULL) {
  130                 /*XXX not right for null algorithm--does it matter??*/
  131                 IPSEC_ASSERT(sav->tdb_encalgxform != NULL,
  132                         ("SA with null xform"));
  133                 if (sav->flags & SADB_X_EXT_OLD)
  134                         size = sizeof (struct esp);
  135                 else
  136                         size = sizeof (struct newesp);
  137                 size += sav->tdb_encalgxform->blocksize + 9;
  138                 /*XXX need alg check???*/
  139                 if (sav->tdb_authalgxform != NULL && sav->replay)
  140                         size += ah_hdrsiz(sav);
  141         } else {
  142                 /*
  143                  *   base header size
  144                  * + max iv length for CBC mode
  145                  * + max pad length
  146                  * + sizeof (pad length field)
  147                  * + sizeof (next header field)
  148                  * + max icv supported.
  149                  */
  150                 size = sizeof (struct newesp) + V_esp_max_ivlen + 9 + 16;
  151         }
  152         return size;
  153 }
  154 
  155 /*
  156  * esp_init() is called when an SPI is being set up.
  157  */
  158 static int
  159 esp_init(struct secasvar *sav, struct xformsw *xsp)
  160 {
  161         struct enc_xform *txform;
  162         struct cryptoini cria, crie;
  163         int keylen;
  164         int error;
  165 
  166         txform = esp_algorithm_lookup(sav->alg_enc);
  167         if (txform == NULL) {
  168                 DPRINTF(("%s: unsupported encryption algorithm %d\n",
  169                         __func__, sav->alg_enc));
  170                 return EINVAL;
  171         }
  172         if (sav->key_enc == NULL) {
  173                 DPRINTF(("%s: no encoding key for %s algorithm\n",
  174                          __func__, txform->name));
  175                 return EINVAL;
  176         }
  177         if ((sav->flags&(SADB_X_EXT_OLD|SADB_X_EXT_IV4B)) == SADB_X_EXT_IV4B) {
  178                 DPRINTF(("%s: 4-byte IV not supported with protocol\n",
  179                         __func__));
  180                 return EINVAL;
  181         }
  182         keylen = _KEYLEN(sav->key_enc);
  183         if (txform->minkey > keylen || keylen > txform->maxkey) {
  184                 DPRINTF(("%s: invalid key length %u, must be in the range "
  185                         "[%u..%u] for algorithm %s\n", __func__,
  186                         keylen, txform->minkey, txform->maxkey,
  187                         txform->name));
  188                 return EINVAL;
  189         }
  190 
  191         /*
  192          * NB: The null xform needs a non-zero blocksize to keep the
  193          *      crypto code happy but if we use it to set ivlen then
  194          *      the ESP header will be processed incorrectly.  The
  195          *      compromise is to force it to zero here.
  196          */
  197         sav->ivlen = (txform == &enc_xform_null ? 0 : txform->blocksize);
  198         sav->iv = (caddr_t) malloc(sav->ivlen, M_XDATA, M_WAITOK);
  199         if (sav->iv == NULL) {
  200                 DPRINTF(("%s: no memory for IV\n", __func__));
  201                 return EINVAL;
  202         }
  203         key_randomfill(sav->iv, sav->ivlen);    /*XXX*/
  204 
  205         /*
  206          * Setup AH-related state.
  207          */
  208         if (sav->alg_auth != 0) {
  209                 error = ah_init0(sav, xsp, &cria);
  210                 if (error)
  211                         return error;
  212         }
  213 
  214         /* NB: override anything set in ah_init0 */
  215         sav->tdb_xform = xsp;
  216         sav->tdb_encalgxform = txform;
  217 
  218         /* Initialize crypto session. */
  219         bzero(&crie, sizeof (crie));
  220         crie.cri_alg = sav->tdb_encalgxform->type;
  221         crie.cri_klen = _KEYBITS(sav->key_enc);
  222         crie.cri_key = sav->key_enc->key_data;
  223         /* XXX Rounds ? */
  224 
  225         if (sav->tdb_authalgxform && sav->tdb_encalgxform) {
  226                 /* init both auth & enc */
  227                 crie.cri_next = &cria;
  228                 error = crypto_newsession(&sav->tdb_cryptoid,
  229                                           &crie, V_crypto_support);
  230         } else if (sav->tdb_encalgxform) {
  231                 error = crypto_newsession(&sav->tdb_cryptoid,
  232                                           &crie, V_crypto_support);
  233         } else if (sav->tdb_authalgxform) {
  234                 error = crypto_newsession(&sav->tdb_cryptoid,
  235                                           &cria, V_crypto_support);
  236         } else {
  237                 /* XXX cannot happen? */
  238                 DPRINTF(("%s: no encoding OR authentication xform!\n",
  239                         __func__));
  240                 error = EINVAL;
  241         }
  242         return error;
  243 }
  244 
  245 /*
  246  * Paranoia.
  247  */
  248 static int
  249 esp_zeroize(struct secasvar *sav)
  250 {
  251         /* NB: ah_zerorize free's the crypto session state */
  252         int error = ah_zeroize(sav);
  253 
  254         if (sav->key_enc)
  255                 bzero(sav->key_enc->key_data, _KEYLEN(sav->key_enc));
  256         if (sav->iv) {
  257                 free(sav->iv, M_XDATA);
  258                 sav->iv = NULL;
  259         }
  260         sav->tdb_encalgxform = NULL;
  261         sav->tdb_xform = NULL;
  262         return error;
  263 }
  264 
  265 /*
  266  * ESP input processing, called (eventually) through the protocol switch.
  267  */
  268 static int
  269 esp_input(struct mbuf *m, struct secasvar *sav, int skip, int protoff)
  270 {
  271         struct auth_hash *esph;
  272         struct enc_xform *espx;
  273         struct tdb_ident *tdbi;
  274         struct tdb_crypto *tc;
  275         int plen, alen, hlen;
  276         struct m_tag *mtag;
  277         struct newesp *esp;
  278 
  279         struct cryptodesc *crde;
  280         struct cryptop *crp;
  281 
  282         IPSEC_ASSERT(sav != NULL, ("null SA"));
  283         IPSEC_ASSERT(sav->tdb_encalgxform != NULL, ("null encoding xform"));
  284 
  285         /* Valid IP Packet length ? */
  286         if ( (skip&3) || (m->m_pkthdr.len&3) ){
  287                 DPRINTF(("%s: misaligned packet, skip %u pkt len %u",
  288                                 __func__, skip, m->m_pkthdr.len));
  289                 ESPSTAT_INC(esps_badilen);
  290                 m_freem(m);
  291                 return EINVAL;
  292         }
  293 
  294         /* XXX don't pullup, just copy header */
  295         IP6_EXTHDR_GET(esp, struct newesp *, m, skip, sizeof (struct newesp));
  296 
  297         esph = sav->tdb_authalgxform;
  298         espx = sav->tdb_encalgxform;
  299 
  300         /* Determine the ESP header length */
  301         if (sav->flags & SADB_X_EXT_OLD)
  302                 hlen = sizeof (struct esp) + sav->ivlen;
  303         else
  304                 hlen = sizeof (struct newesp) + sav->ivlen;
  305         /* Authenticator hash size */
  306         if (esph != NULL) {
  307                 switch (esph->type) {
  308                 case CRYPTO_SHA2_256_HMAC:
  309                 case CRYPTO_SHA2_384_HMAC:
  310                 case CRYPTO_SHA2_512_HMAC:
  311                         alen = esph->hashsize/2;
  312                         break;
  313                 default:
  314                         alen = AH_HMAC_HASHLEN;
  315                         break;
  316                 }
  317         }else
  318                 alen = 0;
  319 
  320         /*
  321          * Verify payload length is multiple of encryption algorithm
  322          * block size.
  323          *
  324          * NB: This works for the null algorithm because the blocksize
  325          *     is 4 and all packets must be 4-byte aligned regardless
  326          *     of the algorithm.
  327          */
  328         plen = m->m_pkthdr.len - (skip + hlen + alen);
  329         if ((plen & (espx->blocksize - 1)) || (plen <= 0)) {
  330                 DPRINTF(("%s: payload of %d octets not a multiple of %d octets,"
  331                     "  SA %s/%08lx\n", __func__,
  332                     plen, espx->blocksize,
  333                     ipsec_address(&sav->sah->saidx.dst),
  334                     (u_long) ntohl(sav->spi)));
  335                 ESPSTAT_INC(esps_badilen);
  336                 m_freem(m);
  337                 return EINVAL;
  338         }
  339 
  340         /*
  341          * Check sequence number.
  342          */
  343         if (esph && sav->replay && !ipsec_chkreplay(ntohl(esp->esp_seq), sav)) {
  344                 DPRINTF(("%s: packet replay check for %s\n", __func__,
  345                     ipsec_logsastr(sav)));      /*XXX*/
  346                 ESPSTAT_INC(esps_replay);
  347                 m_freem(m);
  348                 return ENOBUFS;         /*XXX*/
  349         }
  350 
  351         /* Update the counters */
  352         ESPSTAT_ADD(esps_ibytes, m->m_pkthdr.len - (skip + hlen + alen));
  353 
  354         /* Find out if we've already done crypto */
  355         for (mtag = m_tag_find(m, PACKET_TAG_IPSEC_IN_CRYPTO_DONE, NULL);
  356              mtag != NULL;
  357              mtag = m_tag_find(m, PACKET_TAG_IPSEC_IN_CRYPTO_DONE, mtag)) {
  358                 tdbi = (struct tdb_ident *) (mtag + 1);
  359                 if (tdbi->proto == sav->sah->saidx.proto &&
  360                     tdbi->spi == sav->spi &&
  361                     !bcmp(&tdbi->dst, &sav->sah->saidx.dst,
  362                           sizeof(union sockaddr_union)))
  363                         break;
  364         }
  365 
  366         /* Get crypto descriptors */
  367         crp = crypto_getreq(esph && espx ? 2 : 1);
  368         if (crp == NULL) {
  369                 DPRINTF(("%s: failed to acquire crypto descriptors\n",
  370                         __func__));
  371                 ESPSTAT_INC(esps_crypto);
  372                 m_freem(m);
  373                 return ENOBUFS;
  374         }
  375 
  376         /* Get IPsec-specific opaque pointer */
  377         if (esph == NULL || mtag != NULL)
  378                 tc = (struct tdb_crypto *) malloc(sizeof(struct tdb_crypto),
  379                     M_XDATA, M_NOWAIT|M_ZERO);
  380         else
  381                 tc = (struct tdb_crypto *) malloc(sizeof(struct tdb_crypto) + alen,
  382                     M_XDATA, M_NOWAIT|M_ZERO);
  383         if (tc == NULL) {
  384                 crypto_freereq(crp);
  385                 DPRINTF(("%s: failed to allocate tdb_crypto\n", __func__));
  386                 ESPSTAT_INC(esps_crypto);
  387                 m_freem(m);
  388                 return ENOBUFS;
  389         }
  390 
  391         tc->tc_ptr = (caddr_t) mtag;
  392 
  393         if (esph) {
  394                 struct cryptodesc *crda = crp->crp_desc;
  395 
  396                 IPSEC_ASSERT(crda != NULL, ("null ah crypto descriptor"));
  397 
  398                 /* Authentication descriptor */
  399                 crda->crd_skip = skip;
  400                 crda->crd_len = m->m_pkthdr.len - (skip + alen);
  401                 crda->crd_inject = m->m_pkthdr.len - alen;
  402 
  403                 crda->crd_alg = esph->type;
  404                 crda->crd_key = sav->key_auth->key_data;
  405                 crda->crd_klen = _KEYBITS(sav->key_auth);
  406 
  407                 /* Copy the authenticator */
  408                 if (mtag == NULL)
  409                         m_copydata(m, m->m_pkthdr.len - alen, alen,
  410                                    (caddr_t) (tc + 1));
  411 
  412                 /* Chain authentication request */
  413                 crde = crda->crd_next;
  414         } else {
  415                 crde = crp->crp_desc;
  416         }
  417 
  418         /* Crypto operation descriptor */
  419         crp->crp_ilen = m->m_pkthdr.len; /* Total input length */
  420         crp->crp_flags = CRYPTO_F_IMBUF | CRYPTO_F_CBIFSYNC;
  421         crp->crp_buf = (caddr_t) m;
  422         crp->crp_callback = esp_input_cb;
  423         crp->crp_sid = sav->tdb_cryptoid;
  424         crp->crp_opaque = (caddr_t) tc;
  425 
  426         /* These are passed as-is to the callback */
  427         tc->tc_spi = sav->spi;
  428         tc->tc_dst = sav->sah->saidx.dst;
  429         tc->tc_proto = sav->sah->saidx.proto;
  430         tc->tc_protoff = protoff;
  431         tc->tc_skip = skip;
  432         KEY_ADDREFSA(sav);
  433         tc->tc_sav = sav;
  434 
  435         /* Decryption descriptor */
  436         if (espx) {
  437                 IPSEC_ASSERT(crde != NULL, ("null esp crypto descriptor"));
  438                 crde->crd_skip = skip + hlen;
  439                 crde->crd_len = m->m_pkthdr.len - (skip + hlen + alen);
  440                 crde->crd_inject = skip + hlen - sav->ivlen;
  441 
  442                 crde->crd_alg = espx->type;
  443                 crde->crd_key = sav->key_enc->key_data;
  444                 crde->crd_klen = _KEYBITS(sav->key_enc);
  445                 /* XXX Rounds ? */
  446         }
  447 
  448         if (mtag == NULL)
  449                 return crypto_dispatch(crp);
  450         else
  451                 return esp_input_cb(crp);
  452 }
  453 
  454 /*
  455  * ESP input callback from the crypto driver.
  456  */
  457 static int
  458 esp_input_cb(struct cryptop *crp)
  459 {
  460         u_int8_t lastthree[3], aalg[AH_HMAC_MAXHASHLEN];
  461         int hlen, skip, protoff, error, alen;
  462         struct mbuf *m;
  463         struct cryptodesc *crd;
  464         struct auth_hash *esph;
  465         struct enc_xform *espx;
  466         struct tdb_crypto *tc;
  467         struct m_tag *mtag;
  468         struct secasvar *sav;
  469         struct secasindex *saidx;
  470         caddr_t ptr;
  471 
  472         crd = crp->crp_desc;
  473         IPSEC_ASSERT(crd != NULL, ("null crypto descriptor!"));
  474 
  475         tc = (struct tdb_crypto *) crp->crp_opaque;
  476         IPSEC_ASSERT(tc != NULL, ("null opaque crypto data area!"));
  477         skip = tc->tc_skip;
  478         protoff = tc->tc_protoff;
  479         mtag = (struct m_tag *) tc->tc_ptr;
  480         m = (struct mbuf *) crp->crp_buf;
  481 
  482         sav = tc->tc_sav;
  483         IPSEC_ASSERT(sav != NULL, ("null SA!"));
  484 
  485         saidx = &sav->sah->saidx;
  486         IPSEC_ASSERT(saidx->dst.sa.sa_family == AF_INET ||
  487                 saidx->dst.sa.sa_family == AF_INET6,
  488                 ("unexpected protocol family %u", saidx->dst.sa.sa_family));
  489 
  490         esph = sav->tdb_authalgxform;
  491         espx = sav->tdb_encalgxform;
  492 
  493         /* Check for crypto errors */
  494         if (crp->crp_etype) {
  495                 /* Reset the session ID */
  496                 if (sav->tdb_cryptoid != 0)
  497                         sav->tdb_cryptoid = crp->crp_sid;
  498 
  499                 if (crp->crp_etype == EAGAIN) {
  500                         error = crypto_dispatch(crp);
  501                         return error;
  502                 }
  503 
  504                 ESPSTAT_INC(esps_noxform);
  505                 DPRINTF(("%s: crypto error %d\n", __func__, crp->crp_etype));
  506                 error = crp->crp_etype;
  507                 goto bad;
  508         }
  509 
  510         /* Shouldn't happen... */
  511         if (m == NULL) {
  512                 ESPSTAT_INC(esps_crypto);
  513                 DPRINTF(("%s: bogus returned buffer from crypto\n", __func__));
  514                 error = EINVAL;
  515                 goto bad;
  516         }
  517         ESPSTAT_INC(esps_hist[sav->alg_enc]);
  518 
  519         /* If authentication was performed, check now. */
  520         if (esph != NULL) {
  521                 switch (esph->type) {
  522                 case CRYPTO_SHA2_256_HMAC:
  523                 case CRYPTO_SHA2_384_HMAC:
  524                 case CRYPTO_SHA2_512_HMAC:
  525                         alen = esph->hashsize/2;
  526                         break;
  527                 default:
  528                         alen = AH_HMAC_HASHLEN;
  529                         break;
  530                 }
  531                 /*
  532                  * If we have a tag, it means an IPsec-aware NIC did
  533                  * the verification for us.  Otherwise we need to
  534                  * check the authentication calculation.
  535                  */
  536                 AHSTAT_INC(ahs_hist[sav->alg_auth]);
  537                 if (mtag == NULL) {
  538                         /* Copy the authenticator from the packet */
  539                         m_copydata(m, m->m_pkthdr.len - alen,
  540                                 alen, aalg);
  541 
  542                         ptr = (caddr_t) (tc + 1);
  543 
  544                         /* Verify authenticator */
  545                         if (bcmp(ptr, aalg, alen) != 0) {
  546                                 DPRINTF(("%s: "
  547                     "authentication hash mismatch for packet in SA %s/%08lx\n",
  548                                     __func__,
  549                                     ipsec_address(&saidx->dst),
  550                                     (u_long) ntohl(sav->spi)));
  551                                 ESPSTAT_INC(esps_badauth);
  552                                 error = EACCES;
  553                                 goto bad;
  554                         }
  555                 }
  556 
  557                 /* Remove trailing authenticator */
  558                 m_adj(m, -alen);
  559         }
  560 
  561         /* Release the crypto descriptors */
  562         free(tc, M_XDATA), tc = NULL;
  563         crypto_freereq(crp), crp = NULL;
  564 
  565         /*
  566          * Packet is now decrypted.
  567          */
  568         m->m_flags |= M_DECRYPTED;
  569 
  570         /*
  571          * Update replay sequence number, if appropriate.
  572          */
  573         if (sav->replay) {
  574                 u_int32_t seq;
  575 
  576                 m_copydata(m, skip + offsetof(struct newesp, esp_seq),
  577                            sizeof (seq), (caddr_t) &seq);
  578                 if (ipsec_updatereplay(ntohl(seq), sav)) {
  579                         DPRINTF(("%s: packet replay check for %s\n", __func__,
  580                             ipsec_logsastr(sav)));
  581                         ESPSTAT_INC(esps_replay);
  582                         error = ENOBUFS;
  583                         goto bad;
  584                 }
  585         }
  586 
  587         /* Determine the ESP header length */
  588         if (sav->flags & SADB_X_EXT_OLD)
  589                 hlen = sizeof (struct esp) + sav->ivlen;
  590         else
  591                 hlen = sizeof (struct newesp) + sav->ivlen;
  592 
  593         /* Remove the ESP header and IV from the mbuf. */
  594         error = m_striphdr(m, skip, hlen);
  595         if (error) {
  596                 ESPSTAT_INC(esps_hdrops);
  597                 DPRINTF(("%s: bad mbuf chain, SA %s/%08lx\n", __func__,
  598                     ipsec_address(&sav->sah->saidx.dst),
  599                     (u_long) ntohl(sav->spi)));
  600                 goto bad;
  601         }
  602 
  603         /* Save the last three bytes of decrypted data */
  604         m_copydata(m, m->m_pkthdr.len - 3, 3, lastthree);
  605 
  606         /* Verify pad length */
  607         if (lastthree[1] + 2 > m->m_pkthdr.len - skip) {
  608                 ESPSTAT_INC(esps_badilen);
  609                 DPRINTF(("%s: invalid padding length %d for %u byte packet "
  610                         "in SA %s/%08lx\n", __func__,
  611                          lastthree[1], m->m_pkthdr.len - skip,
  612                          ipsec_address(&sav->sah->saidx.dst),
  613                          (u_long) ntohl(sav->spi)));
  614                 error = EINVAL;
  615                 goto bad;
  616         }
  617 
  618         /* Verify correct decryption by checking the last padding bytes */
  619         if ((sav->flags & SADB_X_EXT_PMASK) != SADB_X_EXT_PRAND) {
  620                 if (lastthree[1] != lastthree[0] && lastthree[1] != 0) {
  621                         ESPSTAT_INC(esps_badenc);
  622                         DPRINTF(("%s: decryption failed for packet in "
  623                                 "SA %s/%08lx\n", __func__,
  624                                 ipsec_address(&sav->sah->saidx.dst),
  625                                 (u_long) ntohl(sav->spi)));
  626                         error = EINVAL;
  627                         goto bad;
  628                 }
  629         }
  630 
  631         /* Trim the mbuf chain to remove trailing authenticator and padding */
  632         m_adj(m, -(lastthree[1] + 2));
  633 
  634         /* Restore the Next Protocol field */
  635         m_copyback(m, protoff, sizeof (u_int8_t), lastthree + 2);
  636 
  637         switch (saidx->dst.sa.sa_family) {
  638 #ifdef INET6
  639         case AF_INET6:
  640                 error = ipsec6_common_input_cb(m, sav, skip, protoff, mtag);
  641                 break;
  642 #endif
  643 #ifdef INET
  644         case AF_INET:
  645                 error = ipsec4_common_input_cb(m, sav, skip, protoff, mtag);
  646                 break;
  647 #endif
  648         default:
  649                 panic("%s: Unexpected address family: %d saidx=%p", __func__,
  650                     saidx->dst.sa.sa_family, saidx);
  651         }
  652 
  653         KEY_FREESAV(&sav);
  654         return error;
  655 bad:
  656         if (sav)
  657                 KEY_FREESAV(&sav);
  658         if (m != NULL)
  659                 m_freem(m);
  660         if (tc != NULL)
  661                 free(tc, M_XDATA);
  662         if (crp != NULL)
  663                 crypto_freereq(crp);
  664         return error;
  665 }
  666 
  667 /*
  668  * ESP output routine, called by ipsec[46]_process_packet().
  669  */
  670 static int
  671 esp_output(
  672         struct mbuf *m,
  673         struct ipsecrequest *isr,
  674         struct mbuf **mp,
  675         int skip,
  676         int protoff
  677 )
  678 {
  679         struct enc_xform *espx;
  680         struct auth_hash *esph;
  681         int hlen, rlen, plen, padding, blks, alen, i, roff;
  682         struct mbuf *mo = (struct mbuf *) NULL;
  683         struct tdb_crypto *tc;
  684         struct secasvar *sav;
  685         struct secasindex *saidx;
  686         unsigned char *pad;
  687         u_int8_t prot;
  688         int error, maxpacketsize;
  689 
  690         struct cryptodesc *crde = NULL, *crda = NULL;
  691         struct cryptop *crp;
  692 
  693         sav = isr->sav;
  694         IPSEC_ASSERT(sav != NULL, ("null SA"));
  695         esph = sav->tdb_authalgxform;
  696         espx = sav->tdb_encalgxform;
  697         IPSEC_ASSERT(espx != NULL, ("null encoding xform"));
  698 
  699         if (sav->flags & SADB_X_EXT_OLD)
  700                 hlen = sizeof (struct esp) + sav->ivlen;
  701         else
  702                 hlen = sizeof (struct newesp) + sav->ivlen;
  703 
  704         rlen = m->m_pkthdr.len - skip;  /* Raw payload length. */
  705         /*
  706          * NB: The null encoding transform has a blocksize of 4
  707          *     so that headers are properly aligned.
  708          */
  709         blks = espx->blocksize;         /* IV blocksize */
  710 
  711         /* XXX clamp padding length a la KAME??? */
  712         padding = ((blks - ((rlen + 2) % blks)) % blks) + 2;
  713         plen = rlen + padding;          /* Padded payload length. */
  714 
  715         if (esph)
  716                 switch (esph->type) {
  717                 case CRYPTO_SHA2_256_HMAC:
  718                 case CRYPTO_SHA2_384_HMAC:
  719                 case CRYPTO_SHA2_512_HMAC:
  720                         alen = esph->hashsize/2;
  721                         break;
  722                 default:
  723                 alen = AH_HMAC_HASHLEN;
  724                         break;
  725                 }
  726         else
  727                 alen = 0;
  728 
  729         ESPSTAT_INC(esps_output);
  730 
  731         saidx = &sav->sah->saidx;
  732         /* Check for maximum packet size violations. */
  733         switch (saidx->dst.sa.sa_family) {
  734 #ifdef INET
  735         case AF_INET:
  736                 maxpacketsize = IP_MAXPACKET;
  737                 break;
  738 #endif /* INET */
  739 #ifdef INET6
  740         case AF_INET6:
  741                 maxpacketsize = IPV6_MAXPACKET;
  742                 break;
  743 #endif /* INET6 */
  744         default:
  745                 DPRINTF(("%s: unknown/unsupported protocol "
  746                     "family %d, SA %s/%08lx\n", __func__,
  747                     saidx->dst.sa.sa_family, ipsec_address(&saidx->dst),
  748                     (u_long) ntohl(sav->spi)));
  749                 ESPSTAT_INC(esps_nopf);
  750                 error = EPFNOSUPPORT;
  751                 goto bad;
  752         }
  753         if (skip + hlen + rlen + padding + alen > maxpacketsize) {
  754                 DPRINTF(("%s: packet in SA %s/%08lx got too big "
  755                     "(len %u, max len %u)\n", __func__,
  756                     ipsec_address(&saidx->dst), (u_long) ntohl(sav->spi),
  757                     skip + hlen + rlen + padding + alen, maxpacketsize));
  758                 ESPSTAT_INC(esps_toobig);
  759                 error = EMSGSIZE;
  760                 goto bad;
  761         }
  762 
  763         /* Update the counters. */
  764         ESPSTAT_ADD(esps_obytes, m->m_pkthdr.len - skip);
  765 
  766         m = m_unshare(m, M_NOWAIT);
  767         if (m == NULL) {
  768                 DPRINTF(("%s: cannot clone mbuf chain, SA %s/%08lx\n", __func__,
  769                     ipsec_address(&saidx->dst), (u_long) ntohl(sav->spi)));
  770                 ESPSTAT_INC(esps_hdrops);
  771                 error = ENOBUFS;
  772                 goto bad;
  773         }
  774 
  775         /* Inject ESP header. */
  776         mo = m_makespace(m, skip, hlen, &roff);
  777         if (mo == NULL) {
  778                 DPRINTF(("%s: %u byte ESP hdr inject failed for SA %s/%08lx\n",
  779                     __func__, hlen, ipsec_address(&saidx->dst),
  780                     (u_long) ntohl(sav->spi)));
  781                 ESPSTAT_INC(esps_hdrops);               /* XXX diffs from openbsd */
  782                 error = ENOBUFS;
  783                 goto bad;
  784         }
  785 
  786         /* Initialize ESP header. */
  787         bcopy((caddr_t) &sav->spi, mtod(mo, caddr_t) + roff, sizeof(u_int32_t));
  788         if (sav->replay) {
  789                 u_int32_t replay;
  790 
  791 #ifdef REGRESSION
  792                 /* Emulate replay attack when ipsec_replay is TRUE. */
  793                 if (!V_ipsec_replay)
  794 #endif
  795                         sav->replay->count++;
  796                 replay = htonl(sav->replay->count);
  797                 bcopy((caddr_t) &replay,
  798                     mtod(mo, caddr_t) + roff + sizeof(u_int32_t),
  799                     sizeof(u_int32_t));
  800         }
  801 
  802         /*
  803          * Add padding -- better to do it ourselves than use the crypto engine,
  804          * although if/when we support compression, we'd have to do that.
  805          */
  806         pad = (u_char *) m_pad(m, padding + alen);
  807         if (pad == NULL) {
  808                 DPRINTF(("%s: m_pad failed for SA %s/%08lx\n", __func__,
  809                     ipsec_address(&saidx->dst), (u_long) ntohl(sav->spi)));
  810                 m = NULL;               /* NB: free'd by m_pad */
  811                 error = ENOBUFS;
  812                 goto bad;
  813         }
  814 
  815         /*
  816          * Add padding: random, zero, or self-describing.
  817          * XXX catch unexpected setting
  818          */
  819         switch (sav->flags & SADB_X_EXT_PMASK) {
  820         case SADB_X_EXT_PRAND:
  821                 (void) read_random(pad, padding - 2);
  822                 break;
  823         case SADB_X_EXT_PZERO:
  824                 bzero(pad, padding - 2);
  825                 break;
  826         case SADB_X_EXT_PSEQ:
  827                 for (i = 0; i < padding - 2; i++)
  828                         pad[i] = i+1;
  829                 break;
  830         }
  831 
  832         /* Fix padding length and Next Protocol in padding itself. */
  833         pad[padding - 2] = padding - 2;
  834         m_copydata(m, protoff, sizeof(u_int8_t), pad + padding - 1);
  835 
  836         /* Fix Next Protocol in IPv4/IPv6 header. */
  837         prot = IPPROTO_ESP;
  838         m_copyback(m, protoff, sizeof(u_int8_t), (u_char *) &prot);
  839 
  840         /* Get crypto descriptors. */
  841         crp = crypto_getreq(esph && espx ? 2 : 1);
  842         if (crp == NULL) {
  843                 DPRINTF(("%s: failed to acquire crypto descriptors\n",
  844                         __func__));
  845                 ESPSTAT_INC(esps_crypto);
  846                 error = ENOBUFS;
  847                 goto bad;
  848         }
  849 
  850         if (espx) {
  851                 crde = crp->crp_desc;
  852                 crda = crde->crd_next;
  853 
  854                 /* Encryption descriptor. */
  855                 crde->crd_skip = skip + hlen;
  856                 crde->crd_len = m->m_pkthdr.len - (skip + hlen + alen);
  857                 crde->crd_flags = CRD_F_ENCRYPT;
  858                 crde->crd_inject = skip + hlen - sav->ivlen;
  859 
  860                 /* Encryption operation. */
  861                 crde->crd_alg = espx->type;
  862                 crde->crd_key = sav->key_enc->key_data;
  863                 crde->crd_klen = _KEYBITS(sav->key_enc);
  864                 /* XXX Rounds ? */
  865         } else
  866                 crda = crp->crp_desc;
  867 
  868         /* IPsec-specific opaque crypto info. */
  869         tc = (struct tdb_crypto *) malloc(sizeof(struct tdb_crypto),
  870                 M_XDATA, M_NOWAIT|M_ZERO);
  871         if (tc == NULL) {
  872                 crypto_freereq(crp);
  873                 DPRINTF(("%s: failed to allocate tdb_crypto\n", __func__));
  874                 ESPSTAT_INC(esps_crypto);
  875                 error = ENOBUFS;
  876                 goto bad;
  877         }
  878 
  879         /* Callback parameters */
  880         tc->tc_isr = isr;
  881         KEY_ADDREFSA(sav);
  882         tc->tc_sav = sav;
  883         tc->tc_spi = sav->spi;
  884         tc->tc_dst = saidx->dst;
  885         tc->tc_proto = saidx->proto;
  886 
  887         /* Crypto operation descriptor. */
  888         crp->crp_ilen = m->m_pkthdr.len; /* Total input length. */
  889         crp->crp_flags = CRYPTO_F_IMBUF | CRYPTO_F_CBIFSYNC;
  890         crp->crp_buf = (caddr_t) m;
  891         crp->crp_callback = esp_output_cb;
  892         crp->crp_opaque = (caddr_t) tc;
  893         crp->crp_sid = sav->tdb_cryptoid;
  894 
  895         if (esph) {
  896                 /* Authentication descriptor. */
  897                 crda->crd_skip = skip;
  898                 crda->crd_len = m->m_pkthdr.len - (skip + alen);
  899                 crda->crd_inject = m->m_pkthdr.len - alen;
  900 
  901                 /* Authentication operation. */
  902                 crda->crd_alg = esph->type;
  903                 crda->crd_key = sav->key_auth->key_data;
  904                 crda->crd_klen = _KEYBITS(sav->key_auth);
  905         }
  906 
  907         return crypto_dispatch(crp);
  908 bad:
  909         if (m)
  910                 m_freem(m);
  911         return (error);
  912 }
  913 
  914 /*
  915  * ESP output callback from the crypto driver.
  916  */
  917 static int
  918 esp_output_cb(struct cryptop *crp)
  919 {
  920         struct tdb_crypto *tc;
  921         struct ipsecrequest *isr;
  922         struct secasvar *sav;
  923         struct mbuf *m;
  924         int err, error;
  925 
  926         tc = (struct tdb_crypto *) crp->crp_opaque;
  927         IPSEC_ASSERT(tc != NULL, ("null opaque data area!"));
  928         m = (struct mbuf *) crp->crp_buf;
  929 
  930         isr = tc->tc_isr;
  931         IPSECREQUEST_LOCK(isr);
  932         sav = tc->tc_sav;
  933         /* With the isr lock released SA pointer can be updated. */
  934         if (sav != isr->sav) {
  935                 ESPSTAT_INC(esps_notdb);
  936                 DPRINTF(("%s: SA gone during crypto (SA %s/%08lx proto %u)\n",
  937                     __func__, ipsec_address(&tc->tc_dst),
  938                     (u_long) ntohl(tc->tc_spi), tc->tc_proto));
  939                 error = ENOBUFS;                /*XXX*/
  940                 goto bad;
  941         }
  942 
  943         /* Check for crypto errors. */
  944         if (crp->crp_etype) {
  945                 /* Reset session ID. */
  946                 if (sav->tdb_cryptoid != 0)
  947                         sav->tdb_cryptoid = crp->crp_sid;
  948 
  949                 if (crp->crp_etype == EAGAIN) {
  950                         IPSECREQUEST_UNLOCK(isr);
  951                         error = crypto_dispatch(crp);
  952                         return error;
  953                 }
  954 
  955                 ESPSTAT_INC(esps_noxform);
  956                 DPRINTF(("%s: crypto error %d\n", __func__, crp->crp_etype));
  957                 error = crp->crp_etype;
  958                 goto bad;
  959         }
  960 
  961         /* Shouldn't happen... */
  962         if (m == NULL) {
  963                 ESPSTAT_INC(esps_crypto);
  964                 DPRINTF(("%s: bogus returned buffer from crypto\n", __func__));
  965                 error = EINVAL;
  966                 goto bad;
  967         }
  968         ESPSTAT_INC(esps_hist[sav->alg_enc]);
  969         if (sav->tdb_authalgxform != NULL)
  970                 AHSTAT_INC(ahs_hist[sav->alg_auth]);
  971 
  972         /* Release crypto descriptors. */
  973         free(tc, M_XDATA);
  974         crypto_freereq(crp);
  975 
  976 #ifdef REGRESSION
  977         /* Emulate man-in-the-middle attack when ipsec_integrity is TRUE. */
  978         if (V_ipsec_integrity) {
  979                 static unsigned char ipseczeroes[AH_HMAC_MAXHASHLEN];
  980                 struct auth_hash *esph;
  981 
  982                 /*
  983                  * Corrupt HMAC if we want to test integrity verification of
  984                  * the other side.
  985                  */
  986                 esph = sav->tdb_authalgxform;
  987                 if (esph !=  NULL) {
  988                         int alen;
  989 
  990                         switch (esph->type) {
  991                         case CRYPTO_SHA2_256_HMAC:
  992                         case CRYPTO_SHA2_384_HMAC:
  993                         case CRYPTO_SHA2_512_HMAC:
  994                                 alen = esph->hashsize/2;
  995                                 break;
  996                         default:
  997                                 alen = AH_HMAC_HASHLEN;
  998                                 break;
  999                         }
 1000                         m_copyback(m, m->m_pkthdr.len - alen,
 1001                             alen, ipseczeroes);
 1002                 }
 1003         }
 1004 #endif
 1005 
 1006         /* NB: m is reclaimed by ipsec_process_done. */
 1007         err = ipsec_process_done(m, isr);
 1008         KEY_FREESAV(&sav);
 1009         IPSECREQUEST_UNLOCK(isr);
 1010         return err;
 1011 bad:
 1012         if (sav)
 1013                 KEY_FREESAV(&sav);
 1014         IPSECREQUEST_UNLOCK(isr);
 1015         if (m)
 1016                 m_freem(m);
 1017         free(tc, M_XDATA);
 1018         crypto_freereq(crp);
 1019         return error;
 1020 }
 1021 
 1022 static struct xformsw esp_xformsw = {
 1023         XF_ESP,         XFT_CONF|XFT_AUTH,      "IPsec ESP",
 1024         esp_init,       esp_zeroize,            esp_input,
 1025         esp_output
 1026 };
 1027 
 1028 static void
 1029 esp_attach(void)
 1030 {
 1031 #define MAXIV(xform)                                    \
 1032         if (xform.blocksize > V_esp_max_ivlen)          \
 1033                 V_esp_max_ivlen = xform.blocksize       \
 1034 
 1035         MAXIV(enc_xform_des);           /* SADB_EALG_DESCBC */
 1036         MAXIV(enc_xform_3des);          /* SADB_EALG_3DESCBC */
 1037         MAXIV(enc_xform_rijndael128);   /* SADB_X_EALG_AES */
 1038         MAXIV(enc_xform_blf);           /* SADB_X_EALG_BLOWFISHCBC */
 1039         MAXIV(enc_xform_cast5);         /* SADB_X_EALG_CAST128CBC */
 1040         MAXIV(enc_xform_skipjack);      /* SADB_X_EALG_SKIPJACK */
 1041         MAXIV(enc_xform_null);          /* SADB_EALG_NULL */
 1042         MAXIV(enc_xform_camellia);      /* SADB_X_EALG_CAMELLIACBC */
 1043 
 1044         xform_register(&esp_xformsw);
 1045 #undef MAXIV
 1046 }
 1047 SYSINIT(esp_xform_init, SI_SUB_PROTO_DOMAIN, SI_ORDER_MIDDLE, esp_attach, NULL);

Cache object: e4bdb9b3893cea7bd6665a9fd241a897


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