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/10.1/sys/netipsec/xform_esp.c 253088 2013-07-09 10:08:13Z 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_PCPUSTAT_DEFINE(struct espstat, espstat);
   81 VNET_PCPUSTAT_SYSINIT(espstat);
   82 
   83 #ifdef VIMAGE
   84 VNET_PCPUSTAT_SYSUNINIT(espstat);
   85 #endif /* VIMAGE */
   86 
   87 SYSCTL_DECL(_net_inet_esp);
   88 SYSCTL_VNET_INT(_net_inet_esp, OID_AUTO,
   89         esp_enable,     CTLFLAG_RW,     &VNET_NAME(esp_enable), 0, "");
   90 SYSCTL_VNET_PCPUSTAT(_net_inet_esp, IPSECCTL_STATS, stats,
   91     struct espstat, espstat,
   92     "ESP statistics (struct espstat, netipsec/esp_var.h");
   93 
   94 static int esp_input_cb(struct cryptop *op);
   95 static int esp_output_cb(struct cryptop *crp);
   96 
   97 /*
   98  * NB: this is public for use by the PF_KEY support.
   99  * NB: if you add support here; be sure to add code to esp_attach below!
  100  */
  101 struct enc_xform *
  102 esp_algorithm_lookup(int alg)
  103 {
  104         if (alg >= ESP_ALG_MAX)
  105                 return NULL;
  106         switch (alg) {
  107         case SADB_EALG_DESCBC:
  108                 return &enc_xform_des;
  109         case SADB_EALG_3DESCBC:
  110                 return &enc_xform_3des;
  111         case SADB_X_EALG_AES:
  112                 return &enc_xform_rijndael128;
  113         case SADB_X_EALG_BLOWFISHCBC:
  114                 return &enc_xform_blf;
  115         case SADB_X_EALG_CAST128CBC:
  116                 return &enc_xform_cast5;
  117         case SADB_X_EALG_SKIPJACK:
  118                 return &enc_xform_skipjack;
  119         case SADB_EALG_NULL:
  120                 return &enc_xform_null;
  121         case SADB_X_EALG_CAMELLIACBC:
  122                 return &enc_xform_camellia;
  123         }
  124         return NULL;
  125 }
  126 
  127 size_t
  128 esp_hdrsiz(struct secasvar *sav)
  129 {
  130         size_t size;
  131 
  132         if (sav != NULL) {
  133                 /*XXX not right for null algorithm--does it matter??*/
  134                 IPSEC_ASSERT(sav->tdb_encalgxform != NULL,
  135                         ("SA with null xform"));
  136                 if (sav->flags & SADB_X_EXT_OLD)
  137                         size = sizeof (struct esp);
  138                 else
  139                         size = sizeof (struct newesp);
  140                 size += sav->tdb_encalgxform->blocksize + 9;
  141                 /*XXX need alg check???*/
  142                 if (sav->tdb_authalgxform != NULL && sav->replay)
  143                         size += ah_hdrsiz(sav);
  144         } else {
  145                 /*
  146                  *   base header size
  147                  * + max iv length for CBC mode
  148                  * + max pad length
  149                  * + sizeof (pad length field)
  150                  * + sizeof (next header field)
  151                  * + max icv supported.
  152                  */
  153                 size = sizeof (struct newesp) + EALG_MAX_BLOCK_LEN + 9 + 16;
  154         }
  155         return size;
  156 }
  157 
  158 /*
  159  * esp_init() is called when an SPI is being set up.
  160  */
  161 static int
  162 esp_init(struct secasvar *sav, struct xformsw *xsp)
  163 {
  164         struct enc_xform *txform;
  165         struct cryptoini cria, crie;
  166         int keylen;
  167         int error;
  168 
  169         txform = esp_algorithm_lookup(sav->alg_enc);
  170         if (txform == NULL) {
  171                 DPRINTF(("%s: unsupported encryption algorithm %d\n",
  172                         __func__, sav->alg_enc));
  173                 return EINVAL;
  174         }
  175         if (sav->key_enc == NULL) {
  176                 DPRINTF(("%s: no encoding key for %s algorithm\n",
  177                          __func__, txform->name));
  178                 return EINVAL;
  179         }
  180         if ((sav->flags&(SADB_X_EXT_OLD|SADB_X_EXT_IV4B)) == SADB_X_EXT_IV4B) {
  181                 DPRINTF(("%s: 4-byte IV not supported with protocol\n",
  182                         __func__));
  183                 return EINVAL;
  184         }
  185         keylen = _KEYLEN(sav->key_enc);
  186         if (txform->minkey > keylen || keylen > txform->maxkey) {
  187                 DPRINTF(("%s: invalid key length %u, must be in the range "
  188                         "[%u..%u] for algorithm %s\n", __func__,
  189                         keylen, txform->minkey, txform->maxkey,
  190                         txform->name));
  191                 return EINVAL;
  192         }
  193 
  194         /*
  195          * NB: The null xform needs a non-zero blocksize to keep the
  196          *      crypto code happy but if we use it to set ivlen then
  197          *      the ESP header will be processed incorrectly.  The
  198          *      compromise is to force it to zero here.
  199          */
  200         sav->ivlen = (txform == &enc_xform_null ? 0 : txform->blocksize);
  201         sav->iv = (caddr_t) malloc(sav->ivlen, M_XDATA, M_WAITOK);
  202         key_randomfill(sav->iv, sav->ivlen);    /*XXX*/
  203 
  204         /*
  205          * Setup AH-related state.
  206          */
  207         if (sav->alg_auth != 0) {
  208                 error = ah_init0(sav, xsp, &cria);
  209                 if (error)
  210                         return error;
  211         }
  212 
  213         /* NB: override anything set in ah_init0 */
  214         sav->tdb_xform = xsp;
  215         sav->tdb_encalgxform = txform;
  216 
  217         /* Initialize crypto session. */
  218         bzero(&crie, sizeof (crie));
  219         crie.cri_alg = sav->tdb_encalgxform->type;
  220         crie.cri_klen = _KEYBITS(sav->key_enc);
  221         crie.cri_key = sav->key_enc->key_data;
  222         /* XXX Rounds ? */
  223 
  224         if (sav->tdb_authalgxform && sav->tdb_encalgxform) {
  225                 /* init both auth & enc */
  226                 crie.cri_next = &cria;
  227                 error = crypto_newsession(&sav->tdb_cryptoid,
  228                                           &crie, V_crypto_support);
  229         } else if (sav->tdb_encalgxform) {
  230                 error = crypto_newsession(&sav->tdb_cryptoid,
  231                                           &crie, V_crypto_support);
  232         } else if (sav->tdb_authalgxform) {
  233                 error = crypto_newsession(&sav->tdb_cryptoid,
  234                                           &cria, V_crypto_support);
  235         } else {
  236                 /* XXX cannot happen? */
  237                 DPRINTF(("%s: no encoding OR authentication xform!\n",
  238                         __func__));
  239                 error = EINVAL;
  240         }
  241         return error;
  242 }
  243 
  244 /*
  245  * Paranoia.
  246  */
  247 static int
  248 esp_zeroize(struct secasvar *sav)
  249 {
  250         /* NB: ah_zerorize free's the crypto session state */
  251         int error = ah_zeroize(sav);
  252 
  253         if (sav->key_enc)
  254                 bzero(sav->key_enc->key_data, _KEYLEN(sav->key_enc));
  255         if (sav->iv) {
  256                 free(sav->iv, M_XDATA);
  257                 sav->iv = NULL;
  258         }
  259         sav->tdb_encalgxform = NULL;
  260         sav->tdb_xform = NULL;
  261         return error;
  262 }
  263 
  264 /*
  265  * ESP input processing, called (eventually) through the protocol switch.
  266  */
  267 static int
  268 esp_input(struct mbuf *m, struct secasvar *sav, int skip, int protoff)
  269 {
  270         struct auth_hash *esph;
  271         struct enc_xform *espx;
  272         struct tdb_ident *tdbi;
  273         struct tdb_crypto *tc;
  274         int plen, alen, hlen;
  275         struct m_tag *mtag;
  276         struct newesp *esp;
  277 
  278         struct cryptodesc *crde;
  279         struct cryptop *crp;
  280 
  281         IPSEC_ASSERT(sav != NULL, ("null SA"));
  282         IPSEC_ASSERT(sav->tdb_encalgxform != NULL, ("null encoding xform"));
  283 
  284         /* Valid IP Packet length ? */
  285         if ( (skip&3) || (m->m_pkthdr.len&3) ){
  286                 DPRINTF(("%s: misaligned packet, skip %u pkt len %u",
  287                                 __func__, skip, m->m_pkthdr.len));
  288                 ESPSTAT_INC(esps_badilen);
  289                 m_freem(m);
  290                 return EINVAL;
  291         }
  292 
  293         /* XXX don't pullup, just copy header */
  294         IP6_EXTHDR_GET(esp, struct newesp *, m, skip, sizeof (struct newesp));
  295 
  296         esph = sav->tdb_authalgxform;
  297         espx = sav->tdb_encalgxform;
  298 
  299         /* Determine the ESP header length */
  300         if (sav->flags & SADB_X_EXT_OLD)
  301                 hlen = sizeof (struct esp) + sav->ivlen;
  302         else
  303                 hlen = sizeof (struct newesp) + sav->ivlen;
  304         /* Authenticator hash size */
  305         if (esph != NULL) {
  306                 switch (esph->type) {
  307                 case CRYPTO_SHA2_256_HMAC:
  308                 case CRYPTO_SHA2_384_HMAC:
  309                 case CRYPTO_SHA2_512_HMAC:
  310                         alen = esph->hashsize/2;
  311                         break;
  312                 default:
  313                         alen = AH_HMAC_HASHLEN;
  314                         break;
  315                 }
  316         }else
  317                 alen = 0;
  318 
  319         /*
  320          * Verify payload length is multiple of encryption algorithm
  321          * block size.
  322          *
  323          * NB: This works for the null algorithm because the blocksize
  324          *     is 4 and all packets must be 4-byte aligned regardless
  325          *     of the algorithm.
  326          */
  327         plen = m->m_pkthdr.len - (skip + hlen + alen);
  328         if ((plen & (espx->blocksize - 1)) || (plen <= 0)) {
  329                 DPRINTF(("%s: payload of %d octets not a multiple of %d octets,"
  330                     "  SA %s/%08lx\n", __func__,
  331                     plen, espx->blocksize,
  332                     ipsec_address(&sav->sah->saidx.dst),
  333                     (u_long) ntohl(sav->spi)));
  334                 ESPSTAT_INC(esps_badilen);
  335                 m_freem(m);
  336                 return EINVAL;
  337         }
  338 
  339         /*
  340          * Check sequence number.
  341          */
  342         if (esph && sav->replay && !ipsec_chkreplay(ntohl(esp->esp_seq), sav)) {
  343                 DPRINTF(("%s: packet replay check for %s\n", __func__,
  344                     ipsec_logsastr(sav)));      /*XXX*/
  345                 ESPSTAT_INC(esps_replay);
  346                 m_freem(m);
  347                 return ENOBUFS;         /*XXX*/
  348         }
  349 
  350         /* Update the counters */
  351         ESPSTAT_ADD(esps_ibytes, m->m_pkthdr.len - (skip + hlen + alen));
  352 
  353         /* Find out if we've already done crypto */
  354         for (mtag = m_tag_find(m, PACKET_TAG_IPSEC_IN_CRYPTO_DONE, NULL);
  355              mtag != NULL;
  356              mtag = m_tag_find(m, PACKET_TAG_IPSEC_IN_CRYPTO_DONE, mtag)) {
  357                 tdbi = (struct tdb_ident *) (mtag + 1);
  358                 if (tdbi->proto == sav->sah->saidx.proto &&
  359                     tdbi->spi == sav->spi &&
  360                     !bcmp(&tdbi->dst, &sav->sah->saidx.dst,
  361                           sizeof(union sockaddr_union)))
  362                         break;
  363         }
  364 
  365         /* Get crypto descriptors */
  366         crp = crypto_getreq(esph && espx ? 2 : 1);
  367         if (crp == NULL) {
  368                 DPRINTF(("%s: failed to acquire crypto descriptors\n",
  369                         __func__));
  370                 ESPSTAT_INC(esps_crypto);
  371                 m_freem(m);
  372                 return ENOBUFS;
  373         }
  374 
  375         /* Get IPsec-specific opaque pointer */
  376         if (esph == NULL || mtag != NULL)
  377                 tc = (struct tdb_crypto *) malloc(sizeof(struct tdb_crypto),
  378                     M_XDATA, M_NOWAIT|M_ZERO);
  379         else
  380                 tc = (struct tdb_crypto *) malloc(sizeof(struct tdb_crypto) + alen,
  381                     M_XDATA, M_NOWAIT|M_ZERO);
  382         if (tc == NULL) {
  383                 crypto_freereq(crp);
  384                 DPRINTF(("%s: failed to allocate tdb_crypto\n", __func__));
  385                 ESPSTAT_INC(esps_crypto);
  386                 m_freem(m);
  387                 return ENOBUFS;
  388         }
  389 
  390         tc->tc_ptr = (caddr_t) mtag;
  391 
  392         if (esph) {
  393                 struct cryptodesc *crda = crp->crp_desc;
  394 
  395                 IPSEC_ASSERT(crda != NULL, ("null ah crypto descriptor"));
  396 
  397                 /* Authentication descriptor */
  398                 crda->crd_skip = skip;
  399                 crda->crd_len = m->m_pkthdr.len - (skip + alen);
  400                 crda->crd_inject = m->m_pkthdr.len - alen;
  401 
  402                 crda->crd_alg = esph->type;
  403                 crda->crd_key = sav->key_auth->key_data;
  404                 crda->crd_klen = _KEYBITS(sav->key_auth);
  405 
  406                 /* Copy the authenticator */
  407                 if (mtag == NULL)
  408                         m_copydata(m, m->m_pkthdr.len - alen, alen,
  409                                    (caddr_t) (tc + 1));
  410 
  411                 /* Chain authentication request */
  412                 crde = crda->crd_next;
  413         } else {
  414                 crde = crp->crp_desc;
  415         }
  416 
  417         /* Crypto operation descriptor */
  418         crp->crp_ilen = m->m_pkthdr.len; /* Total input length */
  419         crp->crp_flags = CRYPTO_F_IMBUF | CRYPTO_F_CBIFSYNC;
  420         crp->crp_buf = (caddr_t) m;
  421         crp->crp_callback = esp_input_cb;
  422         crp->crp_sid = sav->tdb_cryptoid;
  423         crp->crp_opaque = (caddr_t) tc;
  424 
  425         /* These are passed as-is to the callback */
  426         tc->tc_spi = sav->spi;
  427         tc->tc_dst = sav->sah->saidx.dst;
  428         tc->tc_proto = sav->sah->saidx.proto;
  429         tc->tc_protoff = protoff;
  430         tc->tc_skip = skip;
  431         KEY_ADDREFSA(sav);
  432         tc->tc_sav = sav;
  433 
  434         /* Decryption descriptor */
  435         if (espx) {
  436                 IPSEC_ASSERT(crde != NULL, ("null esp crypto descriptor"));
  437                 crde->crd_skip = skip + hlen;
  438                 crde->crd_len = m->m_pkthdr.len - (skip + hlen + alen);
  439                 crde->crd_inject = skip + hlen - sav->ivlen;
  440 
  441                 crde->crd_alg = espx->type;
  442                 crde->crd_key = sav->key_enc->key_data;
  443                 crde->crd_klen = _KEYBITS(sav->key_enc);
  444                 /* XXX Rounds ? */
  445         }
  446 
  447         if (mtag == NULL)
  448                 return crypto_dispatch(crp);
  449         else
  450                 return esp_input_cb(crp);
  451 }
  452 
  453 /*
  454  * ESP input callback from the crypto driver.
  455  */
  456 static int
  457 esp_input_cb(struct cryptop *crp)
  458 {
  459         u_int8_t lastthree[3], aalg[AH_HMAC_MAXHASHLEN];
  460         int hlen, skip, protoff, error, alen;
  461         struct mbuf *m;
  462         struct cryptodesc *crd;
  463         struct auth_hash *esph;
  464         struct enc_xform *espx;
  465         struct tdb_crypto *tc;
  466         struct m_tag *mtag;
  467         struct secasvar *sav;
  468         struct secasindex *saidx;
  469         caddr_t ptr;
  470 
  471         crd = crp->crp_desc;
  472         IPSEC_ASSERT(crd != NULL, ("null crypto descriptor!"));
  473 
  474         tc = (struct tdb_crypto *) crp->crp_opaque;
  475         IPSEC_ASSERT(tc != NULL, ("null opaque crypto data area!"));
  476         skip = tc->tc_skip;
  477         protoff = tc->tc_protoff;
  478         mtag = (struct m_tag *) tc->tc_ptr;
  479         m = (struct mbuf *) crp->crp_buf;
  480 
  481         sav = tc->tc_sav;
  482         IPSEC_ASSERT(sav != NULL, ("null SA!"));
  483 
  484         saidx = &sav->sah->saidx;
  485         IPSEC_ASSERT(saidx->dst.sa.sa_family == AF_INET ||
  486                 saidx->dst.sa.sa_family == AF_INET6,
  487                 ("unexpected protocol family %u", saidx->dst.sa.sa_family));
  488 
  489         esph = sav->tdb_authalgxform;
  490         espx = sav->tdb_encalgxform;
  491 
  492         /* Check for crypto errors */
  493         if (crp->crp_etype) {
  494                 /* Reset the session ID */
  495                 if (sav->tdb_cryptoid != 0)
  496                         sav->tdb_cryptoid = crp->crp_sid;
  497 
  498                 if (crp->crp_etype == EAGAIN)
  499                         return (crypto_dispatch(crp));
  500 
  501                 ESPSTAT_INC(esps_noxform);
  502                 DPRINTF(("%s: crypto error %d\n", __func__, crp->crp_etype));
  503                 error = crp->crp_etype;
  504                 goto bad;
  505         }
  506 
  507         /* Shouldn't happen... */
  508         if (m == NULL) {
  509                 ESPSTAT_INC(esps_crypto);
  510                 DPRINTF(("%s: bogus returned buffer from crypto\n", __func__));
  511                 error = EINVAL;
  512                 goto bad;
  513         }
  514         ESPSTAT_INC(esps_hist[sav->alg_enc]);
  515 
  516         /* If authentication was performed, check now. */
  517         if (esph != NULL) {
  518                 switch (esph->type) {
  519                 case CRYPTO_SHA2_256_HMAC:
  520                 case CRYPTO_SHA2_384_HMAC:
  521                 case CRYPTO_SHA2_512_HMAC:
  522                         alen = esph->hashsize/2;
  523                         break;
  524                 default:
  525                         alen = AH_HMAC_HASHLEN;
  526                         break;
  527                 }
  528                 /*
  529                  * If we have a tag, it means an IPsec-aware NIC did
  530                  * the verification for us.  Otherwise we need to
  531                  * check the authentication calculation.
  532                  */
  533                 AHSTAT_INC(ahs_hist[sav->alg_auth]);
  534                 if (mtag == NULL) {
  535                         /* Copy the authenticator from the packet */
  536                         m_copydata(m, m->m_pkthdr.len - alen,
  537                                 alen, aalg);
  538 
  539                         ptr = (caddr_t) (tc + 1);
  540 
  541                         /* Verify authenticator */
  542                         if (bcmp(ptr, aalg, alen) != 0) {
  543                                 DPRINTF(("%s: "
  544                     "authentication hash mismatch for packet in SA %s/%08lx\n",
  545                                     __func__,
  546                                     ipsec_address(&saidx->dst),
  547                                     (u_long) ntohl(sav->spi)));
  548                                 ESPSTAT_INC(esps_badauth);
  549                                 error = EACCES;
  550                                 goto bad;
  551                         }
  552                 }
  553 
  554                 /* Remove trailing authenticator */
  555                 m_adj(m, -alen);
  556         }
  557 
  558         /* Release the crypto descriptors */
  559         free(tc, M_XDATA), tc = NULL;
  560         crypto_freereq(crp), crp = NULL;
  561 
  562         /*
  563          * Packet is now decrypted.
  564          */
  565         m->m_flags |= M_DECRYPTED;
  566 
  567         /*
  568          * Update replay sequence number, if appropriate.
  569          */
  570         if (sav->replay) {
  571                 u_int32_t seq;
  572 
  573                 m_copydata(m, skip + offsetof(struct newesp, esp_seq),
  574                            sizeof (seq), (caddr_t) &seq);
  575                 if (ipsec_updatereplay(ntohl(seq), sav)) {
  576                         DPRINTF(("%s: packet replay check for %s\n", __func__,
  577                             ipsec_logsastr(sav)));
  578                         ESPSTAT_INC(esps_replay);
  579                         error = ENOBUFS;
  580                         goto bad;
  581                 }
  582         }
  583 
  584         /* Determine the ESP header length */
  585         if (sav->flags & SADB_X_EXT_OLD)
  586                 hlen = sizeof (struct esp) + sav->ivlen;
  587         else
  588                 hlen = sizeof (struct newesp) + sav->ivlen;
  589 
  590         /* Remove the ESP header and IV from the mbuf. */
  591         error = m_striphdr(m, skip, hlen);
  592         if (error) {
  593                 ESPSTAT_INC(esps_hdrops);
  594                 DPRINTF(("%s: bad mbuf chain, SA %s/%08lx\n", __func__,
  595                     ipsec_address(&sav->sah->saidx.dst),
  596                     (u_long) ntohl(sav->spi)));
  597                 goto bad;
  598         }
  599 
  600         /* Save the last three bytes of decrypted data */
  601         m_copydata(m, m->m_pkthdr.len - 3, 3, lastthree);
  602 
  603         /* Verify pad length */
  604         if (lastthree[1] + 2 > m->m_pkthdr.len - skip) {
  605                 ESPSTAT_INC(esps_badilen);
  606                 DPRINTF(("%s: invalid padding length %d for %u byte packet "
  607                         "in SA %s/%08lx\n", __func__,
  608                          lastthree[1], m->m_pkthdr.len - skip,
  609                          ipsec_address(&sav->sah->saidx.dst),
  610                          (u_long) ntohl(sav->spi)));
  611                 error = EINVAL;
  612                 goto bad;
  613         }
  614 
  615         /* Verify correct decryption by checking the last padding bytes */
  616         if ((sav->flags & SADB_X_EXT_PMASK) != SADB_X_EXT_PRAND) {
  617                 if (lastthree[1] != lastthree[0] && lastthree[1] != 0) {
  618                         ESPSTAT_INC(esps_badenc);
  619                         DPRINTF(("%s: decryption failed for packet in "
  620                                 "SA %s/%08lx\n", __func__,
  621                                 ipsec_address(&sav->sah->saidx.dst),
  622                                 (u_long) ntohl(sav->spi)));
  623                         error = EINVAL;
  624                         goto bad;
  625                 }
  626         }
  627 
  628         /* Trim the mbuf chain to remove trailing authenticator and padding */
  629         m_adj(m, -(lastthree[1] + 2));
  630 
  631         /* Restore the Next Protocol field */
  632         m_copyback(m, protoff, sizeof (u_int8_t), lastthree + 2);
  633 
  634         switch (saidx->dst.sa.sa_family) {
  635 #ifdef INET6
  636         case AF_INET6:
  637                 error = ipsec6_common_input_cb(m, sav, skip, protoff, mtag);
  638                 break;
  639 #endif
  640 #ifdef INET
  641         case AF_INET:
  642                 error = ipsec4_common_input_cb(m, sav, skip, protoff, mtag);
  643                 break;
  644 #endif
  645         default:
  646                 panic("%s: Unexpected address family: %d saidx=%p", __func__,
  647                     saidx->dst.sa.sa_family, saidx);
  648         }
  649 
  650         KEY_FREESAV(&sav);
  651         return error;
  652 bad:
  653         if (sav)
  654                 KEY_FREESAV(&sav);
  655         if (m != NULL)
  656                 m_freem(m);
  657         if (tc != NULL)
  658                 free(tc, M_XDATA);
  659         if (crp != NULL)
  660                 crypto_freereq(crp);
  661         return error;
  662 }
  663 
  664 /*
  665  * ESP output routine, called by ipsec[46]_process_packet().
  666  */
  667 static int
  668 esp_output(
  669         struct mbuf *m,
  670         struct ipsecrequest *isr,
  671         struct mbuf **mp,
  672         int skip,
  673         int protoff
  674 )
  675 {
  676         struct enc_xform *espx;
  677         struct auth_hash *esph;
  678         int hlen, rlen, padding, blks, alen, i, roff;
  679         struct mbuf *mo = (struct mbuf *) NULL;
  680         struct tdb_crypto *tc;
  681         struct secasvar *sav;
  682         struct secasindex *saidx;
  683         unsigned char *pad;
  684         u_int8_t prot;
  685         int error, maxpacketsize;
  686 
  687         struct cryptodesc *crde = NULL, *crda = NULL;
  688         struct cryptop *crp;
  689 
  690         sav = isr->sav;
  691         IPSEC_ASSERT(sav != NULL, ("null SA"));
  692         esph = sav->tdb_authalgxform;
  693         espx = sav->tdb_encalgxform;
  694         IPSEC_ASSERT(espx != NULL, ("null encoding xform"));
  695 
  696         if (sav->flags & SADB_X_EXT_OLD)
  697                 hlen = sizeof (struct esp) + sav->ivlen;
  698         else
  699                 hlen = sizeof (struct newesp) + sav->ivlen;
  700 
  701         rlen = m->m_pkthdr.len - skip;  /* Raw payload length. */
  702         /*
  703          * NB: The null encoding transform has a blocksize of 4
  704          *     so that headers are properly aligned.
  705          */
  706         blks = espx->blocksize;         /* IV blocksize */
  707 
  708         /* XXX clamp padding length a la KAME??? */
  709         padding = ((blks - ((rlen + 2) % blks)) % blks) + 2;
  710 
  711         if (esph)
  712                 switch (esph->type) {
  713                 case CRYPTO_SHA2_256_HMAC:
  714                 case CRYPTO_SHA2_384_HMAC:
  715                 case CRYPTO_SHA2_512_HMAC:
  716                         alen = esph->hashsize/2;
  717                         break;
  718                 default:
  719                 alen = AH_HMAC_HASHLEN;
  720                         break;
  721                 }
  722         else
  723                 alen = 0;
  724 
  725         ESPSTAT_INC(esps_output);
  726 
  727         saidx = &sav->sah->saidx;
  728         /* Check for maximum packet size violations. */
  729         switch (saidx->dst.sa.sa_family) {
  730 #ifdef INET
  731         case AF_INET:
  732                 maxpacketsize = IP_MAXPACKET;
  733                 break;
  734 #endif /* INET */
  735 #ifdef INET6
  736         case AF_INET6:
  737                 maxpacketsize = IPV6_MAXPACKET;
  738                 break;
  739 #endif /* INET6 */
  740         default:
  741                 DPRINTF(("%s: unknown/unsupported protocol "
  742                     "family %d, SA %s/%08lx\n", __func__,
  743                     saidx->dst.sa.sa_family, ipsec_address(&saidx->dst),
  744                     (u_long) ntohl(sav->spi)));
  745                 ESPSTAT_INC(esps_nopf);
  746                 error = EPFNOSUPPORT;
  747                 goto bad;
  748         }
  749         if (skip + hlen + rlen + padding + alen > maxpacketsize) {
  750                 DPRINTF(("%s: packet in SA %s/%08lx got too big "
  751                     "(len %u, max len %u)\n", __func__,
  752                     ipsec_address(&saidx->dst), (u_long) ntohl(sav->spi),
  753                     skip + hlen + rlen + padding + alen, maxpacketsize));
  754                 ESPSTAT_INC(esps_toobig);
  755                 error = EMSGSIZE;
  756                 goto bad;
  757         }
  758 
  759         /* Update the counters. */
  760         ESPSTAT_ADD(esps_obytes, m->m_pkthdr.len - skip);
  761 
  762         m = m_unshare(m, M_NOWAIT);
  763         if (m == NULL) {
  764                 DPRINTF(("%s: cannot clone mbuf chain, SA %s/%08lx\n", __func__,
  765                     ipsec_address(&saidx->dst), (u_long) ntohl(sav->spi)));
  766                 ESPSTAT_INC(esps_hdrops);
  767                 error = ENOBUFS;
  768                 goto bad;
  769         }
  770 
  771         /* Inject ESP header. */
  772         mo = m_makespace(m, skip, hlen, &roff);
  773         if (mo == NULL) {
  774                 DPRINTF(("%s: %u byte ESP hdr inject failed for SA %s/%08lx\n",
  775                     __func__, hlen, ipsec_address(&saidx->dst),
  776                     (u_long) ntohl(sav->spi)));
  777                 ESPSTAT_INC(esps_hdrops);               /* XXX diffs from openbsd */
  778                 error = ENOBUFS;
  779                 goto bad;
  780         }
  781 
  782         /* Initialize ESP header. */
  783         bcopy((caddr_t) &sav->spi, mtod(mo, caddr_t) + roff, sizeof(u_int32_t));
  784         if (sav->replay) {
  785                 u_int32_t replay;
  786 
  787 #ifdef REGRESSION
  788                 /* Emulate replay attack when ipsec_replay is TRUE. */
  789                 if (!V_ipsec_replay)
  790 #endif
  791                         sav->replay->count++;
  792                 replay = htonl(sav->replay->count);
  793                 bcopy((caddr_t) &replay,
  794                     mtod(mo, caddr_t) + roff + sizeof(u_int32_t),
  795                     sizeof(u_int32_t));
  796         }
  797 
  798         /*
  799          * Add padding -- better to do it ourselves than use the crypto engine,
  800          * although if/when we support compression, we'd have to do that.
  801          */
  802         pad = (u_char *) m_pad(m, padding + alen);
  803         if (pad == NULL) {
  804                 DPRINTF(("%s: m_pad failed for SA %s/%08lx\n", __func__,
  805                     ipsec_address(&saidx->dst), (u_long) ntohl(sav->spi)));
  806                 m = NULL;               /* NB: free'd by m_pad */
  807                 error = ENOBUFS;
  808                 goto bad;
  809         }
  810 
  811         /*
  812          * Add padding: random, zero, or self-describing.
  813          * XXX catch unexpected setting
  814          */
  815         switch (sav->flags & SADB_X_EXT_PMASK) {
  816         case SADB_X_EXT_PRAND:
  817                 (void) read_random(pad, padding - 2);
  818                 break;
  819         case SADB_X_EXT_PZERO:
  820                 bzero(pad, padding - 2);
  821                 break;
  822         case SADB_X_EXT_PSEQ:
  823                 for (i = 0; i < padding - 2; i++)
  824                         pad[i] = i+1;
  825                 break;
  826         }
  827 
  828         /* Fix padding length and Next Protocol in padding itself. */
  829         pad[padding - 2] = padding - 2;
  830         m_copydata(m, protoff, sizeof(u_int8_t), pad + padding - 1);
  831 
  832         /* Fix Next Protocol in IPv4/IPv6 header. */
  833         prot = IPPROTO_ESP;
  834         m_copyback(m, protoff, sizeof(u_int8_t), (u_char *) &prot);
  835 
  836         /* Get crypto descriptors. */
  837         crp = crypto_getreq(esph && espx ? 2 : 1);
  838         if (crp == NULL) {
  839                 DPRINTF(("%s: failed to acquire crypto descriptors\n",
  840                         __func__));
  841                 ESPSTAT_INC(esps_crypto);
  842                 error = ENOBUFS;
  843                 goto bad;
  844         }
  845 
  846         if (espx) {
  847                 crde = crp->crp_desc;
  848                 crda = crde->crd_next;
  849 
  850                 /* Encryption descriptor. */
  851                 crde->crd_skip = skip + hlen;
  852                 crde->crd_len = m->m_pkthdr.len - (skip + hlen + alen);
  853                 crde->crd_flags = CRD_F_ENCRYPT;
  854                 crde->crd_inject = skip + hlen - sav->ivlen;
  855 
  856                 /* Encryption operation. */
  857                 crde->crd_alg = espx->type;
  858                 crde->crd_key = sav->key_enc->key_data;
  859                 crde->crd_klen = _KEYBITS(sav->key_enc);
  860                 /* XXX Rounds ? */
  861         } else
  862                 crda = crp->crp_desc;
  863 
  864         /* IPsec-specific opaque crypto info. */
  865         tc = (struct tdb_crypto *) malloc(sizeof(struct tdb_crypto),
  866                 M_XDATA, M_NOWAIT|M_ZERO);
  867         if (tc == NULL) {
  868                 crypto_freereq(crp);
  869                 DPRINTF(("%s: failed to allocate tdb_crypto\n", __func__));
  870                 ESPSTAT_INC(esps_crypto);
  871                 error = ENOBUFS;
  872                 goto bad;
  873         }
  874 
  875         /* Callback parameters */
  876         tc->tc_isr = isr;
  877         KEY_ADDREFSA(sav);
  878         tc->tc_sav = sav;
  879         tc->tc_spi = sav->spi;
  880         tc->tc_dst = saidx->dst;
  881         tc->tc_proto = saidx->proto;
  882 
  883         /* Crypto operation descriptor. */
  884         crp->crp_ilen = m->m_pkthdr.len; /* Total input length. */
  885         crp->crp_flags = CRYPTO_F_IMBUF | CRYPTO_F_CBIFSYNC;
  886         crp->crp_buf = (caddr_t) m;
  887         crp->crp_callback = esp_output_cb;
  888         crp->crp_opaque = (caddr_t) tc;
  889         crp->crp_sid = sav->tdb_cryptoid;
  890 
  891         if (esph) {
  892                 /* Authentication descriptor. */
  893                 crda->crd_skip = skip;
  894                 crda->crd_len = m->m_pkthdr.len - (skip + alen);
  895                 crda->crd_inject = m->m_pkthdr.len - alen;
  896 
  897                 /* Authentication operation. */
  898                 crda->crd_alg = esph->type;
  899                 crda->crd_key = sav->key_auth->key_data;
  900                 crda->crd_klen = _KEYBITS(sav->key_auth);
  901         }
  902 
  903         return crypto_dispatch(crp);
  904 bad:
  905         if (m)
  906                 m_freem(m);
  907         return (error);
  908 }
  909 
  910 /*
  911  * ESP output callback from the crypto driver.
  912  */
  913 static int
  914 esp_output_cb(struct cryptop *crp)
  915 {
  916         struct tdb_crypto *tc;
  917         struct ipsecrequest *isr;
  918         struct secasvar *sav;
  919         struct mbuf *m;
  920         int error;
  921 
  922         tc = (struct tdb_crypto *) crp->crp_opaque;
  923         IPSEC_ASSERT(tc != NULL, ("null opaque data area!"));
  924         m = (struct mbuf *) crp->crp_buf;
  925 
  926         isr = tc->tc_isr;
  927         IPSECREQUEST_LOCK(isr);
  928         sav = tc->tc_sav;
  929         /* With the isr lock released SA pointer can be updated. */
  930         if (sav != isr->sav) {
  931                 ESPSTAT_INC(esps_notdb);
  932                 DPRINTF(("%s: SA gone during crypto (SA %s/%08lx proto %u)\n",
  933                     __func__, ipsec_address(&tc->tc_dst),
  934                     (u_long) ntohl(tc->tc_spi), tc->tc_proto));
  935                 error = ENOBUFS;                /*XXX*/
  936                 goto bad;
  937         }
  938 
  939         /* Check for crypto errors. */
  940         if (crp->crp_etype) {
  941                 /* Reset session ID. */
  942                 if (sav->tdb_cryptoid != 0)
  943                         sav->tdb_cryptoid = crp->crp_sid;
  944 
  945                 if (crp->crp_etype == EAGAIN) {
  946                         IPSECREQUEST_UNLOCK(isr);
  947                         return (crypto_dispatch(crp));
  948                 }
  949 
  950                 ESPSTAT_INC(esps_noxform);
  951                 DPRINTF(("%s: crypto error %d\n", __func__, crp->crp_etype));
  952                 error = crp->crp_etype;
  953                 goto bad;
  954         }
  955 
  956         /* Shouldn't happen... */
  957         if (m == NULL) {
  958                 ESPSTAT_INC(esps_crypto);
  959                 DPRINTF(("%s: bogus returned buffer from crypto\n", __func__));
  960                 error = EINVAL;
  961                 goto bad;
  962         }
  963         ESPSTAT_INC(esps_hist[sav->alg_enc]);
  964         if (sav->tdb_authalgxform != NULL)
  965                 AHSTAT_INC(ahs_hist[sav->alg_auth]);
  966 
  967         /* Release crypto descriptors. */
  968         free(tc, M_XDATA);
  969         crypto_freereq(crp);
  970 
  971 #ifdef REGRESSION
  972         /* Emulate man-in-the-middle attack when ipsec_integrity is TRUE. */
  973         if (V_ipsec_integrity) {
  974                 static unsigned char ipseczeroes[AH_HMAC_MAXHASHLEN];
  975                 struct auth_hash *esph;
  976 
  977                 /*
  978                  * Corrupt HMAC if we want to test integrity verification of
  979                  * the other side.
  980                  */
  981                 esph = sav->tdb_authalgxform;
  982                 if (esph !=  NULL) {
  983                         int alen;
  984 
  985                         switch (esph->type) {
  986                         case CRYPTO_SHA2_256_HMAC:
  987                         case CRYPTO_SHA2_384_HMAC:
  988                         case CRYPTO_SHA2_512_HMAC:
  989                                 alen = esph->hashsize/2;
  990                                 break;
  991                         default:
  992                                 alen = AH_HMAC_HASHLEN;
  993                                 break;
  994                         }
  995                         m_copyback(m, m->m_pkthdr.len - alen,
  996                             alen, ipseczeroes);
  997                 }
  998         }
  999 #endif
 1000 
 1001         /* NB: m is reclaimed by ipsec_process_done. */
 1002         error = ipsec_process_done(m, isr);
 1003         KEY_FREESAV(&sav);
 1004         IPSECREQUEST_UNLOCK(isr);
 1005         return error;
 1006 bad:
 1007         if (sav)
 1008                 KEY_FREESAV(&sav);
 1009         IPSECREQUEST_UNLOCK(isr);
 1010         if (m)
 1011                 m_freem(m);
 1012         free(tc, M_XDATA);
 1013         crypto_freereq(crp);
 1014         return error;
 1015 }
 1016 
 1017 static struct xformsw esp_xformsw = {
 1018         XF_ESP,         XFT_CONF|XFT_AUTH,      "IPsec ESP",
 1019         esp_init,       esp_zeroize,            esp_input,
 1020         esp_output
 1021 };
 1022 
 1023 static void
 1024 esp_attach(void)
 1025 {
 1026 
 1027         xform_register(&esp_xformsw);
 1028 }
 1029 SYSINIT(esp_xform_init, SI_SUB_PROTO_DOMAIN, SI_ORDER_MIDDLE, esp_attach, NULL);

Cache object: 9356d8dff883d12aa14c104051b0fa0d


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