The Design and Implementation of the FreeBSD Operating System, Second Edition
Now available: The Design and Implementation of the FreeBSD Operating System (Second Edition)


[ source navigation ] [ diff markup ] [ identifier search ] [ freetext search ] [ file search ] [ list types ] [ track identifier ]

FreeBSD/Linux Kernel Cross Reference
sys/netipsec/xform_esp.c

Version: -  FREEBSD  -  FREEBSD-12-STABLE  -  FREEBSD-12-0  -  FREEBSD-11-STABLE  -  FREEBSD-11-2  -  FREEBSD-11-1  -  FREEBSD-11-0  -  FREEBSD-10-STABLE  -  FREEBSD-10-4  -  FREEBSD-10-3  -  FREEBSD-10-2  -  FREEBSD-10-1  -  FREEBSD-10-0  -  FREEBSD-9-STABLE  -  FREEBSD-9-3  -  FREEBSD-9-2  -  FREEBSD-9-1  -  FREEBSD-9-0  -  FREEBSD-8-STABLE  -  FREEBSD-8-4  -  FREEBSD-8-3  -  FREEBSD-8-2  -  FREEBSD-8-1  -  FREEBSD-8-0  -  FREEBSD-7-STABLE  -  FREEBSD-7-4  -  FREEBSD-7-3  -  FREEBSD-7-2  -  FREEBSD-7-1  -  FREEBSD-7-0  -  FREEBSD-6-STABLE  -  FREEBSD-6-4  -  FREEBSD-6-3  -  FREEBSD-6-2  -  FREEBSD-6-1  -  FREEBSD-6-0  -  FREEBSD-5-STABLE  -  FREEBSD-5-5  -  FREEBSD-5-4  -  FREEBSD-5-3  -  FREEBSD-5-2  -  FREEBSD-5-1  -  FREEBSD-5-0  -  FREEBSD-4-STABLE  -  FREEBSD-3-STABLE  -  FREEBSD22  -  linux-2.6  -  linux-2.4.22  -  MK83  -  MK84  -  PLAN9  -  DFBSD  -  NETBSD  -  NETBSD5  -  NETBSD4  -  NETBSD3  -  NETBSD20  -  OPENBSD  -  xnu-517  -  xnu-792  -  xnu-792.6.70  -  xnu-1228  -  xnu-1456.1.26  -  xnu-1699.24.8  -  xnu-2050.18.24  -  OPENSOLARIS  -  minix-3-1-1 
SearchContext: -  none  -  3  -  10 

    1 /*      $FreeBSD: releng/11.0/sys/netipsec/xform_esp.c 290924 2015-11-16 07:10:42Z 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/lock.h>
   48 #include <sys/random.h>
   49 #include <sys/rwlock.h>
   50 #include <sys/sysctl.h>
   51 #include <sys/mutex.h>
   52 #include <machine/atomic.h>
   53 
   54 #include <net/if.h>
   55 #include <net/vnet.h>
   56 
   57 #include <netinet/in.h>
   58 #include <netinet/in_systm.h>
   59 #include <netinet/ip.h>
   60 #include <netinet/ip_ecn.h>
   61 #include <netinet/ip6.h>
   62 
   63 #include <netipsec/ipsec.h>
   64 #include <netipsec/ah.h>
   65 #include <netipsec/ah_var.h>
   66 #include <netipsec/esp.h>
   67 #include <netipsec/esp_var.h>
   68 #include <netipsec/xform.h>
   69 
   70 #ifdef INET6
   71 #include <netinet6/ip6_var.h>
   72 #include <netipsec/ipsec6.h>
   73 #include <netinet6/ip6_ecn.h>
   74 #endif
   75 
   76 #include <netipsec/key.h>
   77 #include <netipsec/key_debug.h>
   78 
   79 #include <opencrypto/cryptodev.h>
   80 #include <opencrypto/xform.h>
   81 
   82 VNET_DEFINE(int, esp_enable) = 1;
   83 VNET_PCPUSTAT_DEFINE(struct espstat, espstat);
   84 VNET_PCPUSTAT_SYSINIT(espstat);
   85 
   86 #ifdef VIMAGE
   87 VNET_PCPUSTAT_SYSUNINIT(espstat);
   88 #endif /* VIMAGE */
   89 
   90 SYSCTL_DECL(_net_inet_esp);
   91 SYSCTL_INT(_net_inet_esp, OID_AUTO, esp_enable,
   92         CTLFLAG_VNET | CTLFLAG_RW, &VNET_NAME(esp_enable), 0, "");
   93 SYSCTL_VNET_PCPUSTAT(_net_inet_esp, IPSECCTL_STATS, stats,
   94     struct espstat, espstat,
   95     "ESP statistics (struct espstat, netipsec/esp_var.h");
   96 
   97 static int esp_input_cb(struct cryptop *op);
   98 static int esp_output_cb(struct cryptop *crp);
   99 
  100 /*
  101  * NB: this is public for use by the PF_KEY support.
  102  * NB: if you add support here; be sure to add code to esp_attach below!
  103  */
  104 struct enc_xform *
  105 esp_algorithm_lookup(int alg)
  106 {
  107         if (alg >= ESP_ALG_MAX)
  108                 return NULL;
  109         switch (alg) {
  110         case SADB_EALG_DESCBC:
  111                 return &enc_xform_des;
  112         case SADB_EALG_3DESCBC:
  113                 return &enc_xform_3des;
  114         case SADB_X_EALG_AES:
  115                 return &enc_xform_rijndael128;
  116         case SADB_X_EALG_BLOWFISHCBC:
  117                 return &enc_xform_blf;
  118         case SADB_X_EALG_CAST128CBC:
  119                 return &enc_xform_cast5;
  120         case SADB_EALG_NULL:
  121                 return &enc_xform_null;
  122         case SADB_X_EALG_CAMELLIACBC:
  123                 return &enc_xform_camellia;
  124         case SADB_X_EALG_AESCTR:
  125                 return &enc_xform_aes_icm;
  126         case SADB_X_EALG_AESGCM16:
  127                 return &enc_xform_aes_nist_gcm;
  128         case SADB_X_EALG_AESGMAC:
  129                 return &enc_xform_aes_nist_gmac;
  130         }
  131         return NULL;
  132 }
  133 
  134 size_t
  135 esp_hdrsiz(struct secasvar *sav)
  136 {
  137         size_t size;
  138 
  139         if (sav != NULL) {
  140                 /*XXX not right for null algorithm--does it matter??*/
  141                 IPSEC_ASSERT(sav->tdb_encalgxform != NULL,
  142                         ("SA with null xform"));
  143                 if (sav->flags & SADB_X_EXT_OLD)
  144                         size = sizeof (struct esp);
  145                 else
  146                         size = sizeof (struct newesp);
  147                 size += sav->tdb_encalgxform->blocksize + 9;
  148                 /*XXX need alg check???*/
  149                 if (sav->tdb_authalgxform != NULL && sav->replay)
  150                         size += ah_hdrsiz(sav);
  151         } else {
  152                 /*
  153                  *   base header size
  154                  * + max iv length for CBC mode
  155                  * + max pad length
  156                  * + sizeof (pad length field)
  157                  * + sizeof (next header field)
  158                  * + max icv supported.
  159                  */
  160                 size = sizeof (struct newesp) + EALG_MAX_BLOCK_LEN + 9 + 16;
  161         }
  162         return size;
  163 }
  164 
  165 /*
  166  * esp_init() is called when an SPI is being set up.
  167  */
  168 static int
  169 esp_init(struct secasvar *sav, struct xformsw *xsp)
  170 {
  171         struct enc_xform *txform;
  172         struct cryptoini cria, crie;
  173         int keylen;
  174         int error;
  175 
  176         txform = esp_algorithm_lookup(sav->alg_enc);
  177         if (txform == NULL) {
  178                 DPRINTF(("%s: unsupported encryption algorithm %d\n",
  179                         __func__, sav->alg_enc));
  180                 return EINVAL;
  181         }
  182         if (sav->key_enc == NULL) {
  183                 DPRINTF(("%s: no encoding key for %s algorithm\n",
  184                          __func__, txform->name));
  185                 return EINVAL;
  186         }
  187         if ((sav->flags & (SADB_X_EXT_OLD | SADB_X_EXT_IV4B)) ==
  188             SADB_X_EXT_IV4B) {
  189                 DPRINTF(("%s: 4-byte IV not supported with protocol\n",
  190                         __func__));
  191                 return EINVAL;
  192         }
  193         /* subtract off the salt, RFC4106, 8.1 and RFC3686, 5.1 */
  194         keylen = _KEYLEN(sav->key_enc) - SAV_ISCTRORGCM(sav) * 4;
  195         if (txform->minkey > keylen || keylen > txform->maxkey) {
  196                 DPRINTF(("%s: invalid key length %u, must be in the range "
  197                         "[%u..%u] for algorithm %s\n", __func__,
  198                         keylen, txform->minkey, txform->maxkey,
  199                         txform->name));
  200                 return EINVAL;
  201         }
  202 
  203         if (SAV_ISCTRORGCM(sav))
  204                 sav->ivlen = 8; /* RFC4106 3.1 and RFC3686 3.1 */
  205         else
  206                 sav->ivlen = txform->ivsize;
  207 
  208         /*
  209          * Setup AH-related state.
  210          */
  211         if (sav->alg_auth != 0) {
  212                 error = ah_init0(sav, xsp, &cria);
  213                 if (error)
  214                         return error;
  215         }
  216 
  217         /* NB: override anything set in ah_init0 */
  218         sav->tdb_xform = xsp;
  219         sav->tdb_encalgxform = txform;
  220 
  221         /*
  222          * Whenever AES-GCM is used for encryption, one
  223          * of the AES authentication algorithms is chosen
  224          * as well, based on the key size.
  225          */
  226         if (sav->alg_enc == SADB_X_EALG_AESGCM16) {
  227                 switch (keylen) {
  228                 case AES_128_GMAC_KEY_LEN:
  229                         sav->alg_auth = SADB_X_AALG_AES128GMAC;
  230                         sav->tdb_authalgxform = &auth_hash_nist_gmac_aes_128;
  231                         break;
  232                 case AES_192_GMAC_KEY_LEN:
  233                         sav->alg_auth = SADB_X_AALG_AES192GMAC;
  234                         sav->tdb_authalgxform = &auth_hash_nist_gmac_aes_192;
  235                         break;
  236                 case AES_256_GMAC_KEY_LEN:
  237                         sav->alg_auth = SADB_X_AALG_AES256GMAC;
  238                         sav->tdb_authalgxform = &auth_hash_nist_gmac_aes_256;
  239                         break;
  240                 default:
  241                         DPRINTF(("%s: invalid key length %u"
  242                                  "for algorithm %s\n", __func__,
  243                                  keylen, txform->name));
  244                         return EINVAL;
  245                 }
  246                 bzero(&cria, sizeof(cria));
  247                 cria.cri_alg = sav->tdb_authalgxform->type;
  248                 cria.cri_key = sav->key_enc->key_data;
  249                 cria.cri_klen = _KEYBITS(sav->key_enc) - SAV_ISGCM(sav) * 32;
  250         }
  251 
  252         /* Initialize crypto session. */
  253         bzero(&crie, sizeof(crie));
  254         crie.cri_alg = sav->tdb_encalgxform->type;
  255         crie.cri_key = sav->key_enc->key_data;
  256         crie.cri_klen = _KEYBITS(sav->key_enc) - SAV_ISCTRORGCM(sav) * 32;
  257 
  258         if (sav->tdb_authalgxform && sav->tdb_encalgxform) {
  259                 /* init both auth & enc */
  260                 crie.cri_next = &cria;
  261                 error = crypto_newsession(&sav->tdb_cryptoid,
  262                                           &crie, V_crypto_support);
  263         } else if (sav->tdb_encalgxform) {
  264                 error = crypto_newsession(&sav->tdb_cryptoid,
  265                                           &crie, V_crypto_support);
  266         } else if (sav->tdb_authalgxform) {
  267                 error = crypto_newsession(&sav->tdb_cryptoid,
  268                                           &cria, V_crypto_support);
  269         } else {
  270                 /* XXX cannot happen? */
  271                 DPRINTF(("%s: no encoding OR authentication xform!\n",
  272                         __func__));
  273                 error = EINVAL;
  274         }
  275         return error;
  276 }
  277 
  278 /*
  279  * Paranoia.
  280  */
  281 static int
  282 esp_zeroize(struct secasvar *sav)
  283 {
  284         /* NB: ah_zerorize free's the crypto session state */
  285         int error = ah_zeroize(sav);
  286 
  287         if (sav->key_enc)
  288                 bzero(sav->key_enc->key_data, _KEYLEN(sav->key_enc));
  289         sav->tdb_encalgxform = NULL;
  290         sav->tdb_xform = NULL;
  291         return error;
  292 }
  293 
  294 /*
  295  * ESP input processing, called (eventually) through the protocol switch.
  296  */
  297 static int
  298 esp_input(struct mbuf *m, struct secasvar *sav, int skip, int protoff)
  299 {
  300         char buf[128];
  301         struct auth_hash *esph;
  302         struct enc_xform *espx;
  303         struct tdb_crypto *tc;
  304         uint8_t *ivp;
  305         int plen, alen, hlen;
  306         struct newesp *esp;
  307         struct cryptodesc *crde;
  308         struct cryptop *crp;
  309 
  310         IPSEC_ASSERT(sav != NULL, ("null SA"));
  311         IPSEC_ASSERT(sav->tdb_encalgxform != NULL, ("null encoding xform"));
  312 
  313         /* Valid IP Packet length ? */
  314         if ( (skip&3) || (m->m_pkthdr.len&3) ){
  315                 DPRINTF(("%s: misaligned packet, skip %u pkt len %u",
  316                                 __func__, skip, m->m_pkthdr.len));
  317                 ESPSTAT_INC(esps_badilen);
  318                 m_freem(m);
  319                 return EINVAL;
  320         }
  321         /* XXX don't pullup, just copy header */
  322         IP6_EXTHDR_GET(esp, struct newesp *, m, skip, sizeof (struct newesp));
  323 
  324         esph = sav->tdb_authalgxform;
  325         espx = sav->tdb_encalgxform;
  326 
  327         /* Determine the ESP header and auth length */
  328         if (sav->flags & SADB_X_EXT_OLD)
  329                 hlen = sizeof (struct esp) + sav->ivlen;
  330         else
  331                 hlen = sizeof (struct newesp) + sav->ivlen;
  332 
  333         alen = xform_ah_authsize(esph);
  334 
  335         /*
  336          * Verify payload length is multiple of encryption algorithm
  337          * block size.
  338          *
  339          * NB: This works for the null algorithm because the blocksize
  340          *     is 4 and all packets must be 4-byte aligned regardless
  341          *     of the algorithm.
  342          */
  343         plen = m->m_pkthdr.len - (skip + hlen + alen);
  344         if ((plen & (espx->blocksize - 1)) || (plen <= 0)) {
  345                 DPRINTF(("%s: payload of %d octets not a multiple of %d octets,"
  346                     "  SA %s/%08lx\n", __func__, plen, espx->blocksize,
  347                     ipsec_address(&sav->sah->saidx.dst, buf, sizeof(buf)),
  348                     (u_long)ntohl(sav->spi)));
  349                 ESPSTAT_INC(esps_badilen);
  350                 m_freem(m);
  351                 return EINVAL;
  352         }
  353 
  354         /*
  355          * Check sequence number.
  356          */
  357         if (esph != NULL && sav->replay != NULL &&
  358             !ipsec_chkreplay(ntohl(esp->esp_seq), sav)) {
  359                 DPRINTF(("%s: packet replay check for %s\n", __func__,
  360                     ipsec_logsastr(sav, buf, sizeof(buf))));    /*XXX*/
  361                 ESPSTAT_INC(esps_replay);
  362                 m_freem(m);
  363                 return ENOBUFS;         /*XXX*/
  364         }
  365 
  366         /* Update the counters */
  367         ESPSTAT_ADD(esps_ibytes, m->m_pkthdr.len - (skip + hlen + alen));
  368 
  369         /* Get crypto descriptors */
  370         crp = crypto_getreq(esph && espx ? 2 : 1);
  371         if (crp == NULL) {
  372                 DPRINTF(("%s: failed to acquire crypto descriptors\n",
  373                         __func__));
  374                 ESPSTAT_INC(esps_crypto);
  375                 m_freem(m);
  376                 return ENOBUFS;
  377         }
  378 
  379         /* Get IPsec-specific opaque pointer */
  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         if (esph != NULL) {
  391                 struct cryptodesc *crda = crp->crp_desc;
  392 
  393                 IPSEC_ASSERT(crda != NULL, ("null ah crypto descriptor"));
  394 
  395                 /* Authentication descriptor */
  396                 crda->crd_skip = skip;
  397                 if (SAV_ISGCM(sav))
  398                         crda->crd_len = 8;      /* RFC4106 5, SPI + SN */
  399                 else
  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 
  405                 /* Copy the authenticator */
  406                 m_copydata(m, m->m_pkthdr.len - alen, alen,
  407                     (caddr_t) (tc + 1));
  408 
  409                 /* Chain authentication request */
  410                 crde = crda->crd_next;
  411         } else {
  412                 crde = crp->crp_desc;
  413         }
  414 
  415         /* Crypto operation descriptor */
  416         crp->crp_ilen = m->m_pkthdr.len; /* Total input length */
  417         crp->crp_flags = CRYPTO_F_IMBUF | CRYPTO_F_CBIFSYNC;
  418         crp->crp_buf = (caddr_t) m;
  419         crp->crp_callback = esp_input_cb;
  420         crp->crp_sid = sav->tdb_cryptoid;
  421         crp->crp_opaque = (caddr_t) tc;
  422 
  423         /* These are passed as-is to the callback */
  424         tc->tc_spi = sav->spi;
  425         tc->tc_dst = sav->sah->saidx.dst;
  426         tc->tc_proto = sav->sah->saidx.proto;
  427         tc->tc_protoff = protoff;
  428         tc->tc_skip = skip;
  429         KEY_ADDREFSA(sav);
  430         tc->tc_sav = sav;
  431 
  432         /* Decryption descriptor */
  433         IPSEC_ASSERT(crde != NULL, ("null esp crypto descriptor"));
  434         crde->crd_skip = skip + hlen;
  435         crde->crd_len = m->m_pkthdr.len - (skip + hlen + alen);
  436         crde->crd_inject = skip + hlen - sav->ivlen;
  437 
  438         if (SAV_ISCTRORGCM(sav)) {
  439                 ivp = &crde->crd_iv[0];
  440 
  441                 /* GCM IV Format: RFC4106 4 */
  442                 /* CTR IV Format: RFC3686 4 */
  443                 /* Salt is last four bytes of key, RFC4106 8.1 */
  444                 /* Nonce is last four bytes of key, RFC3686 5.1 */
  445                 memcpy(ivp, sav->key_enc->key_data +
  446                     _KEYLEN(sav->key_enc) - 4, 4);
  447 
  448                 if (SAV_ISCTR(sav)) {
  449                         /* Initial block counter is 1, RFC3686 4 */
  450                         be32enc(&ivp[sav->ivlen + 4], 1);
  451                 }
  452 
  453                 m_copydata(m, skip + hlen - sav->ivlen, sav->ivlen, &ivp[4]);
  454                 crde->crd_flags |= CRD_F_IV_EXPLICIT;
  455         }
  456 
  457         crde->crd_alg = espx->type;
  458 
  459         return (crypto_dispatch(crp));
  460 }
  461 
  462 /*
  463  * ESP input callback from the crypto driver.
  464  */
  465 static int
  466 esp_input_cb(struct cryptop *crp)
  467 {
  468         char buf[128];
  469         u_int8_t lastthree[3], aalg[AH_HMAC_MAXHASHLEN];
  470         int hlen, skip, protoff, error, alen;
  471         struct mbuf *m;
  472         struct cryptodesc *crd;
  473         struct auth_hash *esph;
  474         struct enc_xform *espx;
  475         struct tdb_crypto *tc;
  476         struct secasvar *sav;
  477         struct secasindex *saidx;
  478         caddr_t ptr;
  479 
  480         crd = crp->crp_desc;
  481         IPSEC_ASSERT(crd != NULL, ("null crypto descriptor!"));
  482 
  483         tc = (struct tdb_crypto *) crp->crp_opaque;
  484         IPSEC_ASSERT(tc != NULL, ("null opaque crypto data area!"));
  485         skip = tc->tc_skip;
  486         protoff = tc->tc_protoff;
  487         m = (struct mbuf *) crp->crp_buf;
  488 
  489         sav = tc->tc_sav;
  490         IPSEC_ASSERT(sav != NULL, ("null SA!"));
  491 
  492         saidx = &sav->sah->saidx;
  493         IPSEC_ASSERT(saidx->dst.sa.sa_family == AF_INET ||
  494                 saidx->dst.sa.sa_family == AF_INET6,
  495                 ("unexpected protocol family %u", saidx->dst.sa.sa_family));
  496 
  497         esph = sav->tdb_authalgxform;
  498         espx = sav->tdb_encalgxform;
  499 
  500         /* Check for crypto errors */
  501         if (crp->crp_etype) {
  502                 /* Reset the session ID */
  503                 if (sav->tdb_cryptoid != 0)
  504                         sav->tdb_cryptoid = crp->crp_sid;
  505 
  506                 if (crp->crp_etype == EAGAIN)
  507                         return (crypto_dispatch(crp));
  508 
  509                 ESPSTAT_INC(esps_noxform);
  510                 DPRINTF(("%s: crypto error %d\n", __func__, crp->crp_etype));
  511                 error = crp->crp_etype;
  512                 goto bad;
  513         }
  514 
  515         /* Shouldn't happen... */
  516         if (m == NULL) {
  517                 ESPSTAT_INC(esps_crypto);
  518                 DPRINTF(("%s: bogus returned buffer from crypto\n", __func__));
  519                 error = EINVAL;
  520                 goto bad;
  521         }
  522         ESPSTAT_INC(esps_hist[sav->alg_enc]);
  523 
  524         /* If authentication was performed, check now. */
  525         if (esph != NULL) {
  526                 alen = xform_ah_authsize(esph);
  527                 AHSTAT_INC(ahs_hist[sav->alg_auth]);
  528                 /* Copy the authenticator from the packet */
  529                 m_copydata(m, m->m_pkthdr.len - alen, alen, aalg);
  530                 ptr = (caddr_t) (tc + 1);
  531 
  532                 /* Verify authenticator */
  533                 if (timingsafe_bcmp(ptr, aalg, alen) != 0) {
  534                         DPRINTF(("%s: authentication hash mismatch for "
  535                             "packet in SA %s/%08lx\n", __func__,
  536                             ipsec_address(&saidx->dst, buf, sizeof(buf)),
  537                             (u_long) ntohl(sav->spi)));
  538                         ESPSTAT_INC(esps_badauth);
  539                         error = EACCES;
  540                         goto bad;
  541                 }
  542 
  543                 /* Remove trailing authenticator */
  544                 m_adj(m, -alen);
  545         }
  546 
  547         /* Release the crypto descriptors */
  548         free(tc, M_XDATA), tc = NULL;
  549         crypto_freereq(crp), crp = NULL;
  550 
  551         /*
  552          * Packet is now decrypted.
  553          */
  554         m->m_flags |= M_DECRYPTED;
  555 
  556         /*
  557          * Update replay sequence number, if appropriate.
  558          */
  559         if (sav->replay) {
  560                 u_int32_t seq;
  561 
  562                 m_copydata(m, skip + offsetof(struct newesp, esp_seq),
  563                            sizeof (seq), (caddr_t) &seq);
  564                 if (ipsec_updatereplay(ntohl(seq), sav)) {
  565                         DPRINTF(("%s: packet replay check for %s\n", __func__,
  566                             ipsec_logsastr(sav, buf, sizeof(buf))));
  567                         ESPSTAT_INC(esps_replay);
  568                         error = ENOBUFS;
  569                         goto bad;
  570                 }
  571         }
  572 
  573         /* Determine the ESP header length */
  574         if (sav->flags & SADB_X_EXT_OLD)
  575                 hlen = sizeof (struct esp) + sav->ivlen;
  576         else
  577                 hlen = sizeof (struct newesp) + sav->ivlen;
  578 
  579         /* Remove the ESP header and IV from the mbuf. */
  580         error = m_striphdr(m, skip, hlen);
  581         if (error) {
  582                 ESPSTAT_INC(esps_hdrops);
  583                 DPRINTF(("%s: bad mbuf chain, SA %s/%08lx\n", __func__,
  584                     ipsec_address(&sav->sah->saidx.dst, buf, sizeof(buf)),
  585                     (u_long) ntohl(sav->spi)));
  586                 goto bad;
  587         }
  588 
  589         /* Save the last three bytes of decrypted data */
  590         m_copydata(m, m->m_pkthdr.len - 3, 3, lastthree);
  591 
  592         /* Verify pad length */
  593         if (lastthree[1] + 2 > m->m_pkthdr.len - skip) {
  594                 ESPSTAT_INC(esps_badilen);
  595                 DPRINTF(("%s: invalid padding length %d for %u byte packet "
  596                     "in SA %s/%08lx\n", __func__, lastthree[1],
  597                     m->m_pkthdr.len - skip,
  598                     ipsec_address(&sav->sah->saidx.dst, buf, sizeof(buf)),
  599                     (u_long) ntohl(sav->spi)));
  600                 error = EINVAL;
  601                 goto bad;
  602         }
  603 
  604         /* Verify correct decryption by checking the last padding bytes */
  605         if ((sav->flags & SADB_X_EXT_PMASK) != SADB_X_EXT_PRAND) {
  606                 if (lastthree[1] != lastthree[0] && lastthree[1] != 0) {
  607                         ESPSTAT_INC(esps_badenc);
  608                         DPRINTF(("%s: decryption failed for packet in "
  609                             "SA %s/%08lx\n", __func__, ipsec_address(
  610                             &sav->sah->saidx.dst, buf, sizeof(buf)),
  611                             (u_long) ntohl(sav->spi)));
  612                         error = EINVAL;
  613                         goto bad;
  614                 }
  615         }
  616 
  617         /* Trim the mbuf chain to remove trailing authenticator and padding */
  618         m_adj(m, -(lastthree[1] + 2));
  619 
  620         /* Restore the Next Protocol field */
  621         m_copyback(m, protoff, sizeof (u_int8_t), lastthree + 2);
  622 
  623         switch (saidx->dst.sa.sa_family) {
  624 #ifdef INET6
  625         case AF_INET6:
  626                 error = ipsec6_common_input_cb(m, sav, skip, protoff);
  627                 break;
  628 #endif
  629 #ifdef INET
  630         case AF_INET:
  631                 error = ipsec4_common_input_cb(m, sav, skip, protoff);
  632                 break;
  633 #endif
  634         default:
  635                 panic("%s: Unexpected address family: %d saidx=%p", __func__,
  636                     saidx->dst.sa.sa_family, saidx);
  637         }
  638 
  639         KEY_FREESAV(&sav);
  640         return error;
  641 bad:
  642         if (sav)
  643                 KEY_FREESAV(&sav);
  644         if (m != NULL)
  645                 m_freem(m);
  646         if (tc != NULL)
  647                 free(tc, M_XDATA);
  648         if (crp != NULL)
  649                 crypto_freereq(crp);
  650         return error;
  651 }
  652 
  653 /*
  654  * ESP output routine, called by ipsec[46]_process_packet().
  655  */
  656 static int
  657 esp_output(struct mbuf *m, struct ipsecrequest *isr, struct mbuf **mp,
  658     int skip, int protoff)
  659 {
  660         char buf[INET6_ADDRSTRLEN];
  661         struct enc_xform *espx;
  662         struct auth_hash *esph;
  663         uint8_t *ivp;
  664         uint64_t cntr;
  665         int hlen, rlen, padding, blks, alen, i, roff;
  666         struct mbuf *mo = (struct mbuf *) NULL;
  667         struct tdb_crypto *tc;
  668         struct secasvar *sav;
  669         struct secasindex *saidx;
  670         unsigned char *pad;
  671         u_int8_t prot;
  672         int error, maxpacketsize;
  673 
  674         struct cryptodesc *crde = NULL, *crda = NULL;
  675         struct cryptop *crp;
  676 
  677         sav = isr->sav;
  678         IPSEC_ASSERT(sav != NULL, ("null SA"));
  679         esph = sav->tdb_authalgxform;
  680         espx = sav->tdb_encalgxform;
  681         IPSEC_ASSERT(espx != NULL, ("null encoding xform"));
  682 
  683         if (sav->flags & SADB_X_EXT_OLD)
  684                 hlen = sizeof (struct esp) + sav->ivlen;
  685         else
  686                 hlen = sizeof (struct newesp) + sav->ivlen;
  687 
  688         rlen = m->m_pkthdr.len - skip;  /* Raw payload length. */
  689         /*
  690          * RFC4303 2.4 Requires 4 byte alignment.
  691          */
  692         blks = MAX(4, espx->blocksize);         /* Cipher blocksize */
  693 
  694         /* XXX clamp padding length a la KAME??? */
  695         padding = ((blks - ((rlen + 2) % blks)) % blks) + 2;
  696 
  697         alen = xform_ah_authsize(esph);
  698 
  699         ESPSTAT_INC(esps_output);
  700 
  701         saidx = &sav->sah->saidx;
  702         /* Check for maximum packet size violations. */
  703         switch (saidx->dst.sa.sa_family) {
  704 #ifdef INET
  705         case AF_INET:
  706                 maxpacketsize = IP_MAXPACKET;
  707                 break;
  708 #endif /* INET */
  709 #ifdef INET6
  710         case AF_INET6:
  711                 maxpacketsize = IPV6_MAXPACKET;
  712                 break;
  713 #endif /* INET6 */
  714         default:
  715                 DPRINTF(("%s: unknown/unsupported protocol "
  716                     "family %d, SA %s/%08lx\n", __func__,
  717                     saidx->dst.sa.sa_family, ipsec_address(&saidx->dst,
  718                         buf, sizeof(buf)), (u_long) ntohl(sav->spi)));
  719                 ESPSTAT_INC(esps_nopf);
  720                 error = EPFNOSUPPORT;
  721                 goto bad;
  722         }
  723         DPRINTF(("%s: skip %d hlen %d rlen %d padding %d alen %d blksd %d\n",
  724                 __func__, skip, hlen, rlen, padding, alen, blks));
  725         if (skip + hlen + rlen + padding + alen > maxpacketsize) {
  726                 DPRINTF(("%s: packet in SA %s/%08lx got too big "
  727                     "(len %u, max len %u)\n", __func__,
  728                     ipsec_address(&saidx->dst, buf, sizeof(buf)),
  729                     (u_long) ntohl(sav->spi),
  730                     skip + hlen + rlen + padding + alen, maxpacketsize));
  731                 ESPSTAT_INC(esps_toobig);
  732                 error = EMSGSIZE;
  733                 goto bad;
  734         }
  735 
  736         /* Update the counters. */
  737         ESPSTAT_ADD(esps_obytes, m->m_pkthdr.len - skip);
  738 
  739         m = m_unshare(m, M_NOWAIT);
  740         if (m == NULL) {
  741                 DPRINTF(("%s: cannot clone mbuf chain, SA %s/%08lx\n", __func__,
  742                     ipsec_address(&saidx->dst, buf, sizeof(buf)),
  743                     (u_long) ntohl(sav->spi)));
  744                 ESPSTAT_INC(esps_hdrops);
  745                 error = ENOBUFS;
  746                 goto bad;
  747         }
  748 
  749         /* Inject ESP header. */
  750         mo = m_makespace(m, skip, hlen, &roff);
  751         if (mo == NULL) {
  752                 DPRINTF(("%s: %u byte ESP hdr inject failed for SA %s/%08lx\n",
  753                     __func__, hlen, ipsec_address(&saidx->dst, buf,
  754                     sizeof(buf)), (u_long) ntohl(sav->spi)));
  755                 ESPSTAT_INC(esps_hdrops);               /* XXX diffs from openbsd */
  756                 error = ENOBUFS;
  757                 goto bad;
  758         }
  759 
  760         /* Initialize ESP header. */
  761         bcopy((caddr_t) &sav->spi, mtod(mo, caddr_t) + roff, sizeof(u_int32_t));
  762         if (sav->replay) {
  763                 u_int32_t replay;
  764 
  765 #ifdef REGRESSION
  766                 /* Emulate replay attack when ipsec_replay is TRUE. */
  767                 if (!V_ipsec_replay)
  768 #endif
  769                         sav->replay->count++;
  770                 replay = htonl(sav->replay->count);
  771                 bcopy((caddr_t) &replay,
  772                     mtod(mo, caddr_t) + roff + sizeof(u_int32_t),
  773                     sizeof(u_int32_t));
  774         }
  775 
  776         /*
  777          * Add padding -- better to do it ourselves than use the crypto engine,
  778          * although if/when we support compression, we'd have to do that.
  779          */
  780         pad = (u_char *) m_pad(m, padding + alen);
  781         if (pad == NULL) {
  782                 DPRINTF(("%s: m_pad failed for SA %s/%08lx\n", __func__,
  783                     ipsec_address(&saidx->dst, buf, sizeof(buf)),
  784                     (u_long) ntohl(sav->spi)));
  785                 m = NULL;               /* NB: free'd by m_pad */
  786                 error = ENOBUFS;
  787                 goto bad;
  788         }
  789 
  790         /*
  791          * Add padding: random, zero, or self-describing.
  792          * XXX catch unexpected setting
  793          */
  794         switch (sav->flags & SADB_X_EXT_PMASK) {
  795         case SADB_X_EXT_PRAND:
  796                 (void) read_random(pad, padding - 2);
  797                 break;
  798         case SADB_X_EXT_PZERO:
  799                 bzero(pad, padding - 2);
  800                 break;
  801         case SADB_X_EXT_PSEQ:
  802                 for (i = 0; i < padding - 2; i++)
  803                         pad[i] = i+1;
  804                 break;
  805         }
  806 
  807         /* Fix padding length and Next Protocol in padding itself. */
  808         pad[padding - 2] = padding - 2;
  809         m_copydata(m, protoff, sizeof(u_int8_t), pad + padding - 1);
  810 
  811         /* Fix Next Protocol in IPv4/IPv6 header. */
  812         prot = IPPROTO_ESP;
  813         m_copyback(m, protoff, sizeof(u_int8_t), (u_char *) &prot);
  814 
  815         /* Get crypto descriptors. */
  816         crp = crypto_getreq(esph != NULL ? 2 : 1);
  817         if (crp == NULL) {
  818                 DPRINTF(("%s: failed to acquire crypto descriptors\n",
  819                         __func__));
  820                 ESPSTAT_INC(esps_crypto);
  821                 error = ENOBUFS;
  822                 goto bad;
  823         }
  824 
  825         /* IPsec-specific opaque crypto info. */
  826         tc = (struct tdb_crypto *) malloc(sizeof(struct tdb_crypto),
  827             M_XDATA, M_NOWAIT|M_ZERO);
  828         if (tc == NULL) {
  829                 crypto_freereq(crp);
  830                 DPRINTF(("%s: failed to allocate tdb_crypto\n", __func__));
  831                 ESPSTAT_INC(esps_crypto);
  832                 error = ENOBUFS;
  833                 goto bad;
  834         }
  835 
  836         crde = crp->crp_desc;
  837         crda = crde->crd_next;
  838 
  839         /* Encryption descriptor. */
  840         crde->crd_skip = skip + hlen;
  841         crde->crd_len = m->m_pkthdr.len - (skip + hlen + alen);
  842         crde->crd_flags = CRD_F_ENCRYPT;
  843         crde->crd_inject = skip + hlen - sav->ivlen;
  844 
  845         /* Encryption operation. */
  846         crde->crd_alg = espx->type;
  847         if (SAV_ISCTRORGCM(sav)) {
  848                 ivp = &crde->crd_iv[0];
  849 
  850                 /* GCM IV Format: RFC4106 4 */
  851                 /* CTR IV Format: RFC3686 4 */
  852                 /* Salt is last four bytes of key, RFC4106 8.1 */
  853                 /* Nonce is last four bytes of key, RFC3686 5.1 */
  854                 memcpy(ivp, sav->key_enc->key_data +
  855                     _KEYLEN(sav->key_enc) - 4, 4);
  856                 SECASVAR_LOCK(sav);
  857                 cntr = sav->cntr++;
  858                 SECASVAR_UNLOCK(sav);
  859                 be64enc(&ivp[4], cntr);
  860 
  861                 if (SAV_ISCTR(sav)) {
  862                         /* Initial block counter is 1, RFC3686 4 */
  863                         be32enc(&ivp[sav->ivlen + 4], 1);
  864                 }
  865 
  866                 m_copyback(m, skip + hlen - sav->ivlen, sav->ivlen, &ivp[4]);
  867                 crde->crd_flags |= CRD_F_IV_EXPLICIT|CRD_F_IV_PRESENT;
  868         }
  869 
  870         /* Callback parameters */
  871         key_addref(isr->sp);
  872         tc->tc_isr = isr;
  873         KEY_ADDREFSA(sav);
  874         tc->tc_sav = sav;
  875         tc->tc_spi = sav->spi;
  876         tc->tc_dst = saidx->dst;
  877         tc->tc_proto = saidx->proto;
  878 
  879         /* Crypto operation descriptor. */
  880         crp->crp_ilen = m->m_pkthdr.len; /* Total input length. */
  881         crp->crp_flags = CRYPTO_F_IMBUF | CRYPTO_F_CBIFSYNC;
  882         crp->crp_buf = (caddr_t) m;
  883         crp->crp_callback = esp_output_cb;
  884         crp->crp_opaque = (caddr_t) tc;
  885         crp->crp_sid = sav->tdb_cryptoid;
  886 
  887         if (esph) {
  888                 /* Authentication descriptor. */
  889                 crda->crd_alg = esph->type;
  890                 crda->crd_skip = skip;
  891                 if (SAV_ISGCM(sav))
  892                         crda->crd_len = 8;      /* RFC4106 5, SPI + SN */
  893                 else
  894                         crda->crd_len = m->m_pkthdr.len - (skip + alen);
  895                 crda->crd_inject = m->m_pkthdr.len - alen;
  896         }
  897 
  898         return crypto_dispatch(crp);
  899 bad:
  900         if (m)
  901                 m_freem(m);
  902         return (error);
  903 }
  904 
  905 /*
  906  * ESP output callback from the crypto driver.
  907  */
  908 static int
  909 esp_output_cb(struct cryptop *crp)
  910 {
  911         char buf[INET6_ADDRSTRLEN];
  912         struct tdb_crypto *tc;
  913         struct ipsecrequest *isr;
  914         struct secasvar *sav;
  915         struct mbuf *m;
  916         int error;
  917 
  918         tc = (struct tdb_crypto *) crp->crp_opaque;
  919         IPSEC_ASSERT(tc != NULL, ("null opaque data area!"));
  920         m = (struct mbuf *) crp->crp_buf;
  921 
  922         isr = tc->tc_isr;
  923         IPSEC_ASSERT(isr->sp != NULL, ("NULL isr->sp"));
  924         IPSECREQUEST_LOCK(isr);
  925         sav = tc->tc_sav;
  926 
  927         /* With the isr lock released, SA pointer may have changed. */
  928         if (sav != isr->sav) {
  929                 ESPSTAT_INC(esps_notdb);
  930                 DPRINTF(("%s: SA gone during crypto (SA %s/%08lx proto %u)\n",
  931                     __func__, ipsec_address(&tc->tc_dst, buf, sizeof(buf)),
  932                     (u_long) ntohl(tc->tc_spi), tc->tc_proto));
  933                 error = ENOBUFS;                /*XXX*/
  934                 goto bad;
  935         }
  936 
  937         /* Check for crypto errors. */
  938         if (crp->crp_etype) {
  939                 /* Reset session ID. */
  940                 if (sav->tdb_cryptoid != 0)
  941                         sav->tdb_cryptoid = crp->crp_sid;
  942 
  943                 if (crp->crp_etype == EAGAIN) {
  944                         IPSECREQUEST_UNLOCK(isr);
  945                         return (crypto_dispatch(crp));
  946                 }
  947 
  948                 ESPSTAT_INC(esps_noxform);
  949                 DPRINTF(("%s: crypto error %d\n", __func__, crp->crp_etype));
  950                 error = crp->crp_etype;
  951                 goto bad;
  952         }
  953 
  954         /* Shouldn't happen... */
  955         if (m == NULL) {
  956                 ESPSTAT_INC(esps_crypto);
  957                 DPRINTF(("%s: bogus returned buffer from crypto\n", __func__));
  958                 error = EINVAL;
  959                 goto bad;
  960         }
  961         ESPSTAT_INC(esps_hist[sav->alg_enc]);
  962         if (sav->tdb_authalgxform != NULL)
  963                 AHSTAT_INC(ahs_hist[sav->alg_auth]);
  964 
  965         /* Release crypto descriptors. */
  966         free(tc, M_XDATA);
  967         crypto_freereq(crp);
  968 
  969 #ifdef REGRESSION
  970         /* Emulate man-in-the-middle attack when ipsec_integrity is TRUE. */
  971         if (V_ipsec_integrity) {
  972                 static unsigned char ipseczeroes[AH_HMAC_MAXHASHLEN];
  973                 struct auth_hash *esph;
  974 
  975                 /*
  976                  * Corrupt HMAC if we want to test integrity verification of
  977                  * the other side.
  978                  */
  979                 esph = sav->tdb_authalgxform;
  980                 if (esph !=  NULL) {
  981                         int alen;
  982 
  983                         alen = xform_ah_authsize(esph);
  984                         m_copyback(m, m->m_pkthdr.len - alen,
  985                             alen, ipseczeroes);
  986                 }
  987         }
  988 #endif
  989 
  990         /* NB: m is reclaimed by ipsec_process_done. */
  991         error = ipsec_process_done(m, isr);
  992         KEY_FREESAV(&sav);
  993         IPSECREQUEST_UNLOCK(isr);
  994         KEY_FREESP(&isr->sp);
  995         return (error);
  996 bad:
  997         if (sav)
  998                 KEY_FREESAV(&sav);
  999         IPSECREQUEST_UNLOCK(isr);
 1000         KEY_FREESP(&isr->sp);
 1001         if (m)
 1002                 m_freem(m);
 1003         free(tc, M_XDATA);
 1004         crypto_freereq(crp);
 1005         return (error);
 1006 }
 1007 
 1008 static struct xformsw esp_xformsw = {
 1009         XF_ESP,         XFT_CONF|XFT_AUTH,      "IPsec ESP",
 1010         esp_init,       esp_zeroize,            esp_input,
 1011         esp_output
 1012 };
 1013 
 1014 static void
 1015 esp_attach(void)
 1016 {
 1017 
 1018         xform_register(&esp_xformsw);
 1019 }
 1020 SYSINIT(esp_xform_init, SI_SUB_PROTO_DOMAIN, SI_ORDER_MIDDLE, esp_attach, NULL);

Cache object: 974f37dea40f8f31ad101a10bc10d10d


[ source navigation ] [ diff markup ] [ identifier search ] [ freetext search ] [ file search ] [ list types ] [ track identifier ]


This page is part of the FreeBSD/Linux Linux Kernel Cross-Reference, and was automatically generated using a modified version of the LXR engine.