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/11.1/sys/netipsec/xform_esp.c 319599 2017-06-05 11:11:07Z 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/mutex.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 size_t
  101 esp_hdrsiz(struct secasvar *sav)
  102 {
  103         size_t size;
  104 
  105         if (sav != NULL) {
  106                 /*XXX not right for null algorithm--does it matter??*/
  107                 IPSEC_ASSERT(sav->tdb_encalgxform != NULL,
  108                         ("SA with null xform"));
  109                 if (sav->flags & SADB_X_EXT_OLD)
  110                         size = sizeof (struct esp);
  111                 else
  112                         size = sizeof (struct newesp);
  113                 size += sav->tdb_encalgxform->blocksize + 9;
  114                 /*XXX need alg check???*/
  115                 if (sav->tdb_authalgxform != NULL && sav->replay)
  116                         size += ah_hdrsiz(sav);
  117         } else {
  118                 /*
  119                  *   base header size
  120                  * + max iv length for CBC mode
  121                  * + max pad length
  122                  * + sizeof (pad length field)
  123                  * + sizeof (next header field)
  124                  * + max icv supported.
  125                  */
  126                 size = sizeof (struct newesp) + EALG_MAX_BLOCK_LEN + 9 + 16;
  127         }
  128         return size;
  129 }
  130 
  131 /*
  132  * esp_init() is called when an SPI is being set up.
  133  */
  134 static int
  135 esp_init(struct secasvar *sav, struct xformsw *xsp)
  136 {
  137         const struct enc_xform *txform;
  138         struct cryptoini cria, crie;
  139         int keylen;
  140         int error;
  141 
  142         txform = enc_algorithm_lookup(sav->alg_enc);
  143         if (txform == NULL) {
  144                 DPRINTF(("%s: unsupported encryption algorithm %d\n",
  145                         __func__, sav->alg_enc));
  146                 return EINVAL;
  147         }
  148         if (sav->key_enc == NULL) {
  149                 DPRINTF(("%s: no encoding key for %s algorithm\n",
  150                          __func__, txform->name));
  151                 return EINVAL;
  152         }
  153         if ((sav->flags & (SADB_X_EXT_OLD | SADB_X_EXT_IV4B)) ==
  154             SADB_X_EXT_IV4B) {
  155                 DPRINTF(("%s: 4-byte IV not supported with protocol\n",
  156                         __func__));
  157                 return EINVAL;
  158         }
  159         /* subtract off the salt, RFC4106, 8.1 and RFC3686, 5.1 */
  160         keylen = _KEYLEN(sav->key_enc) - SAV_ISCTRORGCM(sav) * 4;
  161         if (txform->minkey > keylen || keylen > txform->maxkey) {
  162                 DPRINTF(("%s: invalid key length %u, must be in the range "
  163                         "[%u..%u] for algorithm %s\n", __func__,
  164                         keylen, txform->minkey, txform->maxkey,
  165                         txform->name));
  166                 return EINVAL;
  167         }
  168 
  169         if (SAV_ISCTRORGCM(sav))
  170                 sav->ivlen = 8; /* RFC4106 3.1 and RFC3686 3.1 */
  171         else
  172                 sav->ivlen = txform->ivsize;
  173 
  174         /*
  175          * Setup AH-related state.
  176          */
  177         if (sav->alg_auth != 0) {
  178                 error = ah_init0(sav, xsp, &cria);
  179                 if (error)
  180                         return error;
  181         }
  182 
  183         /* NB: override anything set in ah_init0 */
  184         sav->tdb_xform = xsp;
  185         sav->tdb_encalgxform = txform;
  186 
  187         /*
  188          * Whenever AES-GCM is used for encryption, one
  189          * of the AES authentication algorithms is chosen
  190          * as well, based on the key size.
  191          */
  192         if (sav->alg_enc == SADB_X_EALG_AESGCM16) {
  193                 switch (keylen) {
  194                 case AES_128_GMAC_KEY_LEN:
  195                         sav->alg_auth = SADB_X_AALG_AES128GMAC;
  196                         sav->tdb_authalgxform = &auth_hash_nist_gmac_aes_128;
  197                         break;
  198                 case AES_192_GMAC_KEY_LEN:
  199                         sav->alg_auth = SADB_X_AALG_AES192GMAC;
  200                         sav->tdb_authalgxform = &auth_hash_nist_gmac_aes_192;
  201                         break;
  202                 case AES_256_GMAC_KEY_LEN:
  203                         sav->alg_auth = SADB_X_AALG_AES256GMAC;
  204                         sav->tdb_authalgxform = &auth_hash_nist_gmac_aes_256;
  205                         break;
  206                 default:
  207                         DPRINTF(("%s: invalid key length %u"
  208                                  "for algorithm %s\n", __func__,
  209                                  keylen, txform->name));
  210                         return EINVAL;
  211                 }
  212                 bzero(&cria, sizeof(cria));
  213                 cria.cri_alg = sav->tdb_authalgxform->type;
  214                 cria.cri_key = sav->key_enc->key_data;
  215                 cria.cri_klen = _KEYBITS(sav->key_enc) - SAV_ISGCM(sav) * 32;
  216         }
  217 
  218         /* Initialize crypto session. */
  219         bzero(&crie, sizeof(crie));
  220         crie.cri_alg = sav->tdb_encalgxform->type;
  221         crie.cri_key = sav->key_enc->key_data;
  222         crie.cri_klen = _KEYBITS(sav->key_enc) - SAV_ISCTRORGCM(sav) * 32;
  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         sav->tdb_encalgxform = NULL;
  256         sav->tdb_xform = NULL;
  257         return error;
  258 }
  259 
  260 /*
  261  * ESP input processing, called (eventually) through the protocol switch.
  262  */
  263 static int
  264 esp_input(struct mbuf *m, struct secasvar *sav, int skip, int protoff)
  265 {
  266         IPSEC_DEBUG_DECLARE(char buf[128]);
  267         const struct auth_hash *esph;
  268         const struct enc_xform *espx;
  269         struct xform_data *xd;
  270         struct cryptodesc *crde;
  271         struct cryptop *crp;
  272         struct newesp *esp;
  273         uint8_t *ivp;
  274         uint64_t cryptoid;
  275         int alen, error, hlen, plen;
  276 
  277         IPSEC_ASSERT(sav != NULL, ("null SA"));
  278         IPSEC_ASSERT(sav->tdb_encalgxform != NULL, ("null encoding xform"));
  279 
  280         error = EINVAL;
  281         /* Valid IP Packet length ? */
  282         if ( (skip&3) || (m->m_pkthdr.len&3) ){
  283                 DPRINTF(("%s: misaligned packet, skip %u pkt len %u",
  284                                 __func__, skip, m->m_pkthdr.len));
  285                 ESPSTAT_INC(esps_badilen);
  286                 goto bad;
  287         }
  288         /* XXX don't pullup, just copy header */
  289         IP6_EXTHDR_GET(esp, struct newesp *, m, skip, sizeof (struct newesp));
  290 
  291         esph = sav->tdb_authalgxform;
  292         espx = sav->tdb_encalgxform;
  293 
  294         /* Determine the ESP header and auth length */
  295         if (sav->flags & SADB_X_EXT_OLD)
  296                 hlen = sizeof (struct esp) + sav->ivlen;
  297         else
  298                 hlen = sizeof (struct newesp) + sav->ivlen;
  299 
  300         alen = xform_ah_authsize(esph);
  301 
  302         /*
  303          * Verify payload length is multiple of encryption algorithm
  304          * block size.
  305          *
  306          * NB: This works for the null algorithm because the blocksize
  307          *     is 4 and all packets must be 4-byte aligned regardless
  308          *     of the algorithm.
  309          */
  310         plen = m->m_pkthdr.len - (skip + hlen + alen);
  311         if ((plen & (espx->blocksize - 1)) || (plen <= 0)) {
  312                 DPRINTF(("%s: payload of %d octets not a multiple of %d octets,"
  313                     "  SA %s/%08lx\n", __func__, plen, espx->blocksize,
  314                     ipsec_address(&sav->sah->saidx.dst, buf, sizeof(buf)),
  315                     (u_long)ntohl(sav->spi)));
  316                 ESPSTAT_INC(esps_badilen);
  317                 goto bad;
  318         }
  319 
  320         /*
  321          * Check sequence number.
  322          */
  323         SECASVAR_LOCK(sav);
  324         if (esph != NULL && sav->replay != NULL && sav->replay->wsize != 0) {
  325                 if (ipsec_chkreplay(ntohl(esp->esp_seq), sav) == 0) {
  326                         SECASVAR_UNLOCK(sav);
  327                         DPRINTF(("%s: packet replay check for %s\n", __func__,
  328                             ipsec_sa2str(sav, buf, sizeof(buf))));
  329                         ESPSTAT_INC(esps_replay);
  330                         error = EACCES;
  331                         goto bad;
  332                 }
  333         }
  334         cryptoid = sav->tdb_cryptoid;
  335         SECASVAR_UNLOCK(sav);
  336 
  337         /* Update the counters */
  338         ESPSTAT_ADD(esps_ibytes, m->m_pkthdr.len - (skip + hlen + alen));
  339 
  340         /* Get crypto descriptors */
  341         crp = crypto_getreq(esph && espx ? 2 : 1);
  342         if (crp == NULL) {
  343                 DPRINTF(("%s: failed to acquire crypto descriptors\n",
  344                         __func__));
  345                 ESPSTAT_INC(esps_crypto);
  346                 error = ENOBUFS;
  347                 goto bad;
  348         }
  349 
  350         /* Get IPsec-specific opaque pointer */
  351         xd = malloc(sizeof(*xd) + alen, M_XDATA, M_NOWAIT | M_ZERO);
  352         if (xd == NULL) {
  353                 DPRINTF(("%s: failed to allocate xform_data\n", __func__));
  354                 ESPSTAT_INC(esps_crypto);
  355                 crypto_freereq(crp);
  356                 error = ENOBUFS;
  357                 goto bad;
  358         }
  359 
  360         if (esph != NULL) {
  361                 struct cryptodesc *crda = crp->crp_desc;
  362 
  363                 IPSEC_ASSERT(crda != NULL, ("null ah crypto descriptor"));
  364 
  365                 /* Authentication descriptor */
  366                 crda->crd_skip = skip;
  367                 if (SAV_ISGCM(sav))
  368                         crda->crd_len = 8;      /* RFC4106 5, SPI + SN */
  369                 else
  370                         crda->crd_len = m->m_pkthdr.len - (skip + alen);
  371                 crda->crd_inject = m->m_pkthdr.len - alen;
  372 
  373                 crda->crd_alg = esph->type;
  374 
  375                 /* Copy the authenticator */
  376                 m_copydata(m, m->m_pkthdr.len - alen, alen,
  377                     (caddr_t) (xd + 1));
  378 
  379                 /* Chain authentication request */
  380                 crde = crda->crd_next;
  381         } else {
  382                 crde = crp->crp_desc;
  383         }
  384 
  385         /* Crypto operation descriptor */
  386         crp->crp_ilen = m->m_pkthdr.len; /* Total input length */
  387         crp->crp_flags = CRYPTO_F_IMBUF | CRYPTO_F_CBIFSYNC;
  388         crp->crp_buf = (caddr_t) m;
  389         crp->crp_callback = esp_input_cb;
  390         crp->crp_sid = cryptoid;
  391         crp->crp_opaque = (caddr_t) xd;
  392 
  393         /* These are passed as-is to the callback */
  394         xd->sav = sav;
  395         xd->protoff = protoff;
  396         xd->skip = skip;
  397         xd->cryptoid = cryptoid;
  398 
  399         /* Decryption descriptor */
  400         IPSEC_ASSERT(crde != NULL, ("null esp crypto descriptor"));
  401         crde->crd_skip = skip + hlen;
  402         crde->crd_len = m->m_pkthdr.len - (skip + hlen + alen);
  403         crde->crd_inject = skip + hlen - sav->ivlen;
  404 
  405         if (SAV_ISCTRORGCM(sav)) {
  406                 ivp = &crde->crd_iv[0];
  407 
  408                 /* GCM IV Format: RFC4106 4 */
  409                 /* CTR IV Format: RFC3686 4 */
  410                 /* Salt is last four bytes of key, RFC4106 8.1 */
  411                 /* Nonce is last four bytes of key, RFC3686 5.1 */
  412                 memcpy(ivp, sav->key_enc->key_data +
  413                     _KEYLEN(sav->key_enc) - 4, 4);
  414 
  415                 if (SAV_ISCTR(sav)) {
  416                         /* Initial block counter is 1, RFC3686 4 */
  417                         be32enc(&ivp[sav->ivlen + 4], 1);
  418                 }
  419 
  420                 m_copydata(m, skip + hlen - sav->ivlen, sav->ivlen, &ivp[4]);
  421                 crde->crd_flags |= CRD_F_IV_EXPLICIT;
  422         }
  423 
  424         crde->crd_alg = espx->type;
  425 
  426         return (crypto_dispatch(crp));
  427 bad:
  428         m_freem(m);
  429         key_freesav(&sav);
  430         return (error);
  431 }
  432 
  433 /*
  434  * ESP input callback from the crypto driver.
  435  */
  436 static int
  437 esp_input_cb(struct cryptop *crp)
  438 {
  439         IPSEC_DEBUG_DECLARE(char buf[128]);
  440         u_int8_t lastthree[3], aalg[AH_HMAC_MAXHASHLEN];
  441         const struct auth_hash *esph;
  442         const struct enc_xform *espx;
  443         struct mbuf *m;
  444         struct cryptodesc *crd;
  445         struct xform_data *xd;
  446         struct secasvar *sav;
  447         struct secasindex *saidx;
  448         caddr_t ptr;
  449         uint64_t cryptoid;
  450         int hlen, skip, protoff, error, alen;
  451 
  452         crd = crp->crp_desc;
  453         IPSEC_ASSERT(crd != NULL, ("null crypto descriptor!"));
  454 
  455         m = (struct mbuf *) crp->crp_buf;
  456         xd = (struct xform_data *) crp->crp_opaque;
  457         sav = xd->sav;
  458         skip = xd->skip;
  459         protoff = xd->protoff;
  460         cryptoid = xd->cryptoid;
  461         saidx = &sav->sah->saidx;
  462         esph = sav->tdb_authalgxform;
  463         espx = sav->tdb_encalgxform;
  464 
  465         /* Check for crypto errors */
  466         if (crp->crp_etype) {
  467                 if (crp->crp_etype == EAGAIN) {
  468                         /* Reset the session ID */
  469                         if (ipsec_updateid(sav, &crp->crp_sid, &cryptoid) != 0)
  470                                 crypto_freesession(cryptoid);
  471                         xd->cryptoid = crp->crp_sid;
  472                         return (crypto_dispatch(crp));
  473                 }
  474                 ESPSTAT_INC(esps_noxform);
  475                 DPRINTF(("%s: crypto error %d\n", __func__, crp->crp_etype));
  476                 error = crp->crp_etype;
  477                 goto bad;
  478         }
  479 
  480         /* Shouldn't happen... */
  481         if (m == NULL) {
  482                 ESPSTAT_INC(esps_crypto);
  483                 DPRINTF(("%s: bogus returned buffer from crypto\n", __func__));
  484                 error = EINVAL;
  485                 goto bad;
  486         }
  487         ESPSTAT_INC(esps_hist[sav->alg_enc]);
  488 
  489         /* If authentication was performed, check now. */
  490         if (esph != NULL) {
  491                 alen = xform_ah_authsize(esph);
  492                 AHSTAT_INC(ahs_hist[sav->alg_auth]);
  493                 /* Copy the authenticator from the packet */
  494                 m_copydata(m, m->m_pkthdr.len - alen, alen, aalg);
  495                 ptr = (caddr_t) (xd + 1);
  496 
  497                 /* Verify authenticator */
  498                 if (timingsafe_bcmp(ptr, aalg, alen) != 0) {
  499                         DPRINTF(("%s: authentication hash mismatch for "
  500                             "packet in SA %s/%08lx\n", __func__,
  501                             ipsec_address(&saidx->dst, buf, sizeof(buf)),
  502                             (u_long) ntohl(sav->spi)));
  503                         ESPSTAT_INC(esps_badauth);
  504                         error = EACCES;
  505                         goto bad;
  506                 }
  507                 m->m_flags |= M_AUTHIPDGM;
  508                 /* Remove trailing authenticator */
  509                 m_adj(m, -alen);
  510         }
  511 
  512         /* Release the crypto descriptors */
  513         free(xd, M_XDATA), xd = NULL;
  514         crypto_freereq(crp), crp = NULL;
  515 
  516         /*
  517          * Packet is now decrypted.
  518          */
  519         m->m_flags |= M_DECRYPTED;
  520 
  521         /*
  522          * Update replay sequence number, if appropriate.
  523          */
  524         if (sav->replay) {
  525                 u_int32_t seq;
  526 
  527                 m_copydata(m, skip + offsetof(struct newesp, esp_seq),
  528                            sizeof (seq), (caddr_t) &seq);
  529                 SECASVAR_LOCK(sav);
  530                 if (ipsec_updatereplay(ntohl(seq), sav)) {
  531                         SECASVAR_UNLOCK(sav);
  532                         DPRINTF(("%s: packet replay check for %s\n", __func__,
  533                             ipsec_sa2str(sav, buf, sizeof(buf))));
  534                         ESPSTAT_INC(esps_replay);
  535                         error = EACCES;
  536                         goto bad;
  537                 }
  538                 SECASVAR_UNLOCK(sav);
  539         }
  540 
  541         /* Determine the ESP header length */
  542         if (sav->flags & SADB_X_EXT_OLD)
  543                 hlen = sizeof (struct esp) + sav->ivlen;
  544         else
  545                 hlen = sizeof (struct newesp) + sav->ivlen;
  546 
  547         /* Remove the ESP header and IV from the mbuf. */
  548         error = m_striphdr(m, skip, hlen);
  549         if (error) {
  550                 ESPSTAT_INC(esps_hdrops);
  551                 DPRINTF(("%s: bad mbuf chain, SA %s/%08lx\n", __func__,
  552                     ipsec_address(&sav->sah->saidx.dst, buf, sizeof(buf)),
  553                     (u_long) ntohl(sav->spi)));
  554                 goto bad;
  555         }
  556 
  557         /* Save the last three bytes of decrypted data */
  558         m_copydata(m, m->m_pkthdr.len - 3, 3, lastthree);
  559 
  560         /* Verify pad length */
  561         if (lastthree[1] + 2 > m->m_pkthdr.len - skip) {
  562                 ESPSTAT_INC(esps_badilen);
  563                 DPRINTF(("%s: invalid padding length %d for %u byte packet "
  564                     "in SA %s/%08lx\n", __func__, lastthree[1],
  565                     m->m_pkthdr.len - skip,
  566                     ipsec_address(&sav->sah->saidx.dst, buf, sizeof(buf)),
  567                     (u_long) ntohl(sav->spi)));
  568                 error = EINVAL;
  569                 goto bad;
  570         }
  571 
  572         /* Verify correct decryption by checking the last padding bytes */
  573         if ((sav->flags & SADB_X_EXT_PMASK) != SADB_X_EXT_PRAND) {
  574                 if (lastthree[1] != lastthree[0] && lastthree[1] != 0) {
  575                         ESPSTAT_INC(esps_badenc);
  576                         DPRINTF(("%s: decryption failed for packet in "
  577                             "SA %s/%08lx\n", __func__, ipsec_address(
  578                             &sav->sah->saidx.dst, buf, sizeof(buf)),
  579                             (u_long) ntohl(sav->spi)));
  580                         error = EINVAL;
  581                         goto bad;
  582                 }
  583         }
  584 
  585         /* Trim the mbuf chain to remove trailing authenticator and padding */
  586         m_adj(m, -(lastthree[1] + 2));
  587 
  588         /* Restore the Next Protocol field */
  589         m_copyback(m, protoff, sizeof (u_int8_t), lastthree + 2);
  590 
  591         switch (saidx->dst.sa.sa_family) {
  592 #ifdef INET6
  593         case AF_INET6:
  594                 error = ipsec6_common_input_cb(m, sav, skip, protoff);
  595                 break;
  596 #endif
  597 #ifdef INET
  598         case AF_INET:
  599                 error = ipsec4_common_input_cb(m, sav, skip, protoff);
  600                 break;
  601 #endif
  602         default:
  603                 panic("%s: Unexpected address family: %d saidx=%p", __func__,
  604                     saidx->dst.sa.sa_family, saidx);
  605         }
  606         return error;
  607 bad:
  608         if (sav != NULL)
  609                 key_freesav(&sav);
  610         if (m != NULL)
  611                 m_freem(m);
  612         if (xd != NULL)
  613                 free(xd, M_XDATA);
  614         if (crp != NULL)
  615                 crypto_freereq(crp);
  616         return error;
  617 }
  618 /*
  619  * ESP output routine, called by ipsec[46]_perform_request().
  620  */
  621 static int
  622 esp_output(struct mbuf *m, struct secpolicy *sp, struct secasvar *sav,
  623     u_int idx, int skip, int protoff)
  624 {
  625         IPSEC_DEBUG_DECLARE(char buf[IPSEC_ADDRSTRLEN]);
  626         struct cryptodesc *crde = NULL, *crda = NULL;
  627         struct cryptop *crp;
  628         const struct auth_hash *esph;
  629         const struct enc_xform *espx;
  630         struct mbuf *mo = NULL;
  631         struct xform_data *xd;
  632         struct secasindex *saidx;
  633         unsigned char *pad;
  634         uint8_t *ivp;
  635         uint64_t cntr, cryptoid;
  636         int hlen, rlen, padding, blks, alen, i, roff;
  637         int error, maxpacketsize;
  638         uint8_t prot;
  639 
  640         IPSEC_ASSERT(sav != NULL, ("null SA"));
  641         esph = sav->tdb_authalgxform;
  642         espx = sav->tdb_encalgxform;
  643         IPSEC_ASSERT(espx != NULL, ("null encoding xform"));
  644 
  645         if (sav->flags & SADB_X_EXT_OLD)
  646                 hlen = sizeof (struct esp) + sav->ivlen;
  647         else
  648                 hlen = sizeof (struct newesp) + sav->ivlen;
  649 
  650         rlen = m->m_pkthdr.len - skip;  /* Raw payload length. */
  651         /*
  652          * RFC4303 2.4 Requires 4 byte alignment.
  653          */
  654         blks = MAX(4, espx->blocksize);         /* Cipher blocksize */
  655 
  656         /* XXX clamp padding length a la KAME??? */
  657         padding = ((blks - ((rlen + 2) % blks)) % blks) + 2;
  658 
  659         alen = xform_ah_authsize(esph);
  660 
  661         ESPSTAT_INC(esps_output);
  662 
  663         saidx = &sav->sah->saidx;
  664         /* Check for maximum packet size violations. */
  665         switch (saidx->dst.sa.sa_family) {
  666 #ifdef INET
  667         case AF_INET:
  668                 maxpacketsize = IP_MAXPACKET;
  669                 break;
  670 #endif /* INET */
  671 #ifdef INET6
  672         case AF_INET6:
  673                 maxpacketsize = IPV6_MAXPACKET;
  674                 break;
  675 #endif /* INET6 */
  676         default:
  677                 DPRINTF(("%s: unknown/unsupported protocol "
  678                     "family %d, SA %s/%08lx\n", __func__,
  679                     saidx->dst.sa.sa_family, ipsec_address(&saidx->dst,
  680                         buf, sizeof(buf)), (u_long) ntohl(sav->spi)));
  681                 ESPSTAT_INC(esps_nopf);
  682                 error = EPFNOSUPPORT;
  683                 goto bad;
  684         }
  685         /*
  686         DPRINTF(("%s: skip %d hlen %d rlen %d padding %d alen %d blksd %d\n",
  687                 __func__, skip, hlen, rlen, padding, alen, blks)); */
  688         if (skip + hlen + rlen + padding + alen > maxpacketsize) {
  689                 DPRINTF(("%s: packet in SA %s/%08lx got too big "
  690                     "(len %u, max len %u)\n", __func__,
  691                     ipsec_address(&saidx->dst, buf, sizeof(buf)),
  692                     (u_long) ntohl(sav->spi),
  693                     skip + hlen + rlen + padding + alen, maxpacketsize));
  694                 ESPSTAT_INC(esps_toobig);
  695                 error = EMSGSIZE;
  696                 goto bad;
  697         }
  698 
  699         /* Update the counters. */
  700         ESPSTAT_ADD(esps_obytes, m->m_pkthdr.len - skip);
  701 
  702         m = m_unshare(m, M_NOWAIT);
  703         if (m == NULL) {
  704                 DPRINTF(("%s: cannot clone mbuf chain, SA %s/%08lx\n", __func__,
  705                     ipsec_address(&saidx->dst, buf, sizeof(buf)),
  706                     (u_long) ntohl(sav->spi)));
  707                 ESPSTAT_INC(esps_hdrops);
  708                 error = ENOBUFS;
  709                 goto bad;
  710         }
  711 
  712         /* Inject ESP header. */
  713         mo = m_makespace(m, skip, hlen, &roff);
  714         if (mo == NULL) {
  715                 DPRINTF(("%s: %u byte ESP hdr inject failed for SA %s/%08lx\n",
  716                     __func__, hlen, ipsec_address(&saidx->dst, buf,
  717                     sizeof(buf)), (u_long) ntohl(sav->spi)));
  718                 ESPSTAT_INC(esps_hdrops);       /* XXX diffs from openbsd */
  719                 error = ENOBUFS;
  720                 goto bad;
  721         }
  722 
  723         /* Initialize ESP header. */
  724         bcopy((caddr_t) &sav->spi, mtod(mo, caddr_t) + roff,
  725             sizeof(uint32_t));
  726         SECASVAR_LOCK(sav);
  727         if (sav->replay) {
  728                 uint32_t replay;
  729 
  730 #ifdef REGRESSION
  731                 /* Emulate replay attack when ipsec_replay is TRUE. */
  732                 if (!V_ipsec_replay)
  733 #endif
  734                         sav->replay->count++;
  735                 replay = htonl(sav->replay->count);
  736 
  737                 bcopy((caddr_t) &replay, mtod(mo, caddr_t) + roff +
  738                     sizeof(uint32_t), sizeof(uint32_t));
  739         }
  740         cryptoid = sav->tdb_cryptoid;
  741         if (SAV_ISCTRORGCM(sav))
  742                 cntr = sav->cntr++;
  743         SECASVAR_UNLOCK(sav);
  744 
  745         /*
  746          * Add padding -- better to do it ourselves than use the crypto engine,
  747          * although if/when we support compression, we'd have to do that.
  748          */
  749         pad = (u_char *) m_pad(m, padding + alen);
  750         if (pad == NULL) {
  751                 DPRINTF(("%s: m_pad failed for SA %s/%08lx\n", __func__,
  752                     ipsec_address(&saidx->dst, buf, sizeof(buf)),
  753                     (u_long) ntohl(sav->spi)));
  754                 m = NULL;               /* NB: free'd by m_pad */
  755                 error = ENOBUFS;
  756                 goto bad;
  757         }
  758 
  759         /*
  760          * Add padding: random, zero, or self-describing.
  761          * XXX catch unexpected setting
  762          */
  763         switch (sav->flags & SADB_X_EXT_PMASK) {
  764         case SADB_X_EXT_PRAND:
  765                 (void) read_random(pad, padding - 2);
  766                 break;
  767         case SADB_X_EXT_PZERO:
  768                 bzero(pad, padding - 2);
  769                 break;
  770         case SADB_X_EXT_PSEQ:
  771                 for (i = 0; i < padding - 2; i++)
  772                         pad[i] = i+1;
  773                 break;
  774         }
  775 
  776         /* Fix padding length and Next Protocol in padding itself. */
  777         pad[padding - 2] = padding - 2;
  778         m_copydata(m, protoff, sizeof(u_int8_t), pad + padding - 1);
  779 
  780         /* Fix Next Protocol in IPv4/IPv6 header. */
  781         prot = IPPROTO_ESP;
  782         m_copyback(m, protoff, sizeof(u_int8_t), (u_char *) &prot);
  783 
  784         /* Get crypto descriptors. */
  785         crp = crypto_getreq(esph != NULL ? 2 : 1);
  786         if (crp == NULL) {
  787                 DPRINTF(("%s: failed to acquire crypto descriptors\n",
  788                         __func__));
  789                 ESPSTAT_INC(esps_crypto);
  790                 error = ENOBUFS;
  791                 goto bad;
  792         }
  793 
  794         /* IPsec-specific opaque crypto info. */
  795         xd =  malloc(sizeof(struct xform_data), M_XDATA, M_NOWAIT | M_ZERO);
  796         if (xd == NULL) {
  797                 crypto_freereq(crp);
  798                 DPRINTF(("%s: failed to allocate xform_data\n", __func__));
  799                 ESPSTAT_INC(esps_crypto);
  800                 error = ENOBUFS;
  801                 goto bad;
  802         }
  803 
  804         crde = crp->crp_desc;
  805         crda = crde->crd_next;
  806 
  807         /* Encryption descriptor. */
  808         crde->crd_skip = skip + hlen;
  809         crde->crd_len = m->m_pkthdr.len - (skip + hlen + alen);
  810         crde->crd_flags = CRD_F_ENCRYPT;
  811         crde->crd_inject = skip + hlen - sav->ivlen;
  812 
  813         /* Encryption operation. */
  814         crde->crd_alg = espx->type;
  815         if (SAV_ISCTRORGCM(sav)) {
  816                 ivp = &crde->crd_iv[0];
  817 
  818                 /* GCM IV Format: RFC4106 4 */
  819                 /* CTR IV Format: RFC3686 4 */
  820                 /* Salt is last four bytes of key, RFC4106 8.1 */
  821                 /* Nonce is last four bytes of key, RFC3686 5.1 */
  822                 memcpy(ivp, sav->key_enc->key_data +
  823                     _KEYLEN(sav->key_enc) - 4, 4);
  824                 be64enc(&ivp[4], cntr);
  825                 if (SAV_ISCTR(sav)) {
  826                         /* Initial block counter is 1, RFC3686 4 */
  827                         /* XXXAE: should we use this only for first packet? */
  828                         be32enc(&ivp[sav->ivlen + 4], 1);
  829                 }
  830 
  831                 m_copyback(m, skip + hlen - sav->ivlen, sav->ivlen, &ivp[4]);
  832                 crde->crd_flags |= CRD_F_IV_EXPLICIT|CRD_F_IV_PRESENT;
  833         }
  834 
  835         /* Callback parameters */
  836         xd->sp = sp;
  837         xd->sav = sav;
  838         xd->idx = idx;
  839         xd->cryptoid = cryptoid;
  840 
  841         /* Crypto operation descriptor. */
  842         crp->crp_ilen = m->m_pkthdr.len; /* Total input length. */
  843         crp->crp_flags = CRYPTO_F_IMBUF | CRYPTO_F_CBIFSYNC;
  844         crp->crp_buf = (caddr_t) m;
  845         crp->crp_callback = esp_output_cb;
  846         crp->crp_opaque = (caddr_t) xd;
  847         crp->crp_sid = cryptoid;
  848 
  849         if (esph) {
  850                 /* Authentication descriptor. */
  851                 crda->crd_alg = esph->type;
  852                 crda->crd_skip = skip;
  853                 if (SAV_ISGCM(sav))
  854                         crda->crd_len = 8;      /* RFC4106 5, SPI + SN */
  855                 else
  856                         crda->crd_len = m->m_pkthdr.len - (skip + alen);
  857                 crda->crd_inject = m->m_pkthdr.len - alen;
  858         }
  859 
  860         return crypto_dispatch(crp);
  861 bad:
  862         if (m)
  863                 m_freem(m);
  864         key_freesav(&sav);
  865         key_freesp(&sp);
  866         return (error);
  867 }
  868 /*
  869  * ESP output callback from the crypto driver.
  870  */
  871 static int
  872 esp_output_cb(struct cryptop *crp)
  873 {
  874         struct xform_data *xd;
  875         struct secpolicy *sp;
  876         struct secasvar *sav;
  877         struct mbuf *m;
  878         uint64_t cryptoid;
  879         u_int idx;
  880         int error;
  881 
  882         xd = (struct xform_data *) crp->crp_opaque;
  883         m = (struct mbuf *) crp->crp_buf;
  884         sp = xd->sp;
  885         sav = xd->sav;
  886         idx = xd->idx;
  887         cryptoid = xd->cryptoid;
  888 
  889         /* Check for crypto errors. */
  890         if (crp->crp_etype) {
  891                 if (crp->crp_etype == EAGAIN) {
  892                         /* Reset the session ID */
  893                         if (ipsec_updateid(sav, &crp->crp_sid, &cryptoid) != 0)
  894                                 crypto_freesession(cryptoid);
  895                         xd->cryptoid = crp->crp_sid;
  896                         return (crypto_dispatch(crp));
  897                 }
  898                 ESPSTAT_INC(esps_noxform);
  899                 DPRINTF(("%s: crypto error %d\n", __func__, crp->crp_etype));
  900                 error = crp->crp_etype;
  901                 m_freem(m);
  902                 goto bad;
  903         }
  904 
  905         /* Shouldn't happen... */
  906         if (m == NULL) {
  907                 ESPSTAT_INC(esps_crypto);
  908                 DPRINTF(("%s: bogus returned buffer from crypto\n", __func__));
  909                 error = EINVAL;
  910                 goto bad;
  911         }
  912         free(xd, M_XDATA);
  913         crypto_freereq(crp);
  914         ESPSTAT_INC(esps_hist[sav->alg_enc]);
  915         if (sav->tdb_authalgxform != NULL)
  916                 AHSTAT_INC(ahs_hist[sav->alg_auth]);
  917 
  918 #ifdef REGRESSION
  919         /* Emulate man-in-the-middle attack when ipsec_integrity is TRUE. */
  920         if (V_ipsec_integrity) {
  921                 static unsigned char ipseczeroes[AH_HMAC_MAXHASHLEN];
  922                 const struct auth_hash *esph;
  923 
  924                 /*
  925                  * Corrupt HMAC if we want to test integrity verification of
  926                  * the other side.
  927                  */
  928                 esph = sav->tdb_authalgxform;
  929                 if (esph !=  NULL) {
  930                         int alen;
  931 
  932                         alen = xform_ah_authsize(esph);
  933                         m_copyback(m, m->m_pkthdr.len - alen,
  934                             alen, ipseczeroes);
  935                 }
  936         }
  937 #endif
  938 
  939         /* NB: m is reclaimed by ipsec_process_done. */
  940         error = ipsec_process_done(m, sp, sav, idx);
  941         return (error);
  942 bad:
  943         free(xd, M_XDATA);
  944         crypto_freereq(crp);
  945         key_freesav(&sav);
  946         key_freesp(&sp);
  947         return (error);
  948 }
  949 
  950 static struct xformsw esp_xformsw = {
  951         .xf_type =      XF_ESP,
  952         .xf_name =      "IPsec ESP",
  953         .xf_init =      esp_init,
  954         .xf_zeroize =   esp_zeroize,
  955         .xf_input =     esp_input,
  956         .xf_output =    esp_output,
  957 };
  958 
  959 SYSINIT(esp_xform_init, SI_SUB_PROTO_DOMAIN, SI_ORDER_MIDDLE,
  960     xform_attach, &esp_xformsw);
  961 SYSUNINIT(esp_xform_uninit, SI_SUB_PROTO_DOMAIN, SI_ORDER_MIDDLE,
  962     xform_detach, &esp_xformsw);

Cache object: a69c966b670c4439fd5f6564bd5d0825


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