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

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    1 /*      $FreeBSD: stable/12/sys/netipsec/xform_esp.c 365277 2020-09-02 20:36:33Z jhb $  */
    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 #include "opt_ipsec.h"
   41 
   42 #include <sys/param.h>
   43 #include <sys/systm.h>
   44 #include <sys/mbuf.h>
   45 #include <sys/socket.h>
   46 #include <sys/syslog.h>
   47 #include <sys/kernel.h>
   48 #include <sys/lock.h>
   49 #include <sys/random.h>
   50 #include <sys/mutex.h>
   51 #include <sys/sysctl.h>
   52 #include <sys/mutex.h>
   53 #include <machine/atomic.h>
   54 
   55 #include <net/if.h>
   56 #include <net/vnet.h>
   57 
   58 #include <netinet/in.h>
   59 #include <netinet/in_systm.h>
   60 #include <netinet/ip.h>
   61 #include <netinet/ip_ecn.h>
   62 #include <netinet/ip6.h>
   63 
   64 #include <netipsec/ipsec.h>
   65 #include <netipsec/ah.h>
   66 #include <netipsec/ah_var.h>
   67 #include <netipsec/esp.h>
   68 #include <netipsec/esp_var.h>
   69 #include <netipsec/xform.h>
   70 
   71 #ifdef INET6
   72 #include <netinet6/ip6_var.h>
   73 #include <netipsec/ipsec6.h>
   74 #include <netinet6/ip6_ecn.h>
   75 #endif
   76 
   77 #include <netipsec/key.h>
   78 #include <netipsec/key_debug.h>
   79 
   80 #include <opencrypto/cryptodev.h>
   81 #include <opencrypto/xform.h>
   82 
   83 VNET_DEFINE(int, esp_enable) = 1;
   84 VNET_PCPUSTAT_DEFINE(struct espstat, espstat);
   85 VNET_PCPUSTAT_SYSINIT(espstat);
   86 
   87 #ifdef VIMAGE
   88 VNET_PCPUSTAT_SYSUNINIT(espstat);
   89 #endif /* VIMAGE */
   90 
   91 SYSCTL_DECL(_net_inet_esp);
   92 SYSCTL_INT(_net_inet_esp, OID_AUTO, esp_enable,
   93         CTLFLAG_VNET | CTLFLAG_RW, &VNET_NAME(esp_enable), 0, "");
   94 SYSCTL_VNET_PCPUSTAT(_net_inet_esp, IPSECCTL_STATS, stats,
   95     struct espstat, espstat,
   96     "ESP statistics (struct espstat, netipsec/esp_var.h");
   97 
   98 static struct timeval deswarn, blfwarn, castwarn, camelliawarn, tdeswarn;
   99 
  100 static int esp_input_cb(struct cryptop *op);
  101 static int esp_output_cb(struct cryptop *crp);
  102 
  103 size_t
  104 esp_hdrsiz(struct secasvar *sav)
  105 {
  106         size_t size;
  107 
  108         if (sav != NULL) {
  109                 /*XXX not right for null algorithm--does it matter??*/
  110                 IPSEC_ASSERT(sav->tdb_encalgxform != NULL,
  111                         ("SA with null xform"));
  112                 if (sav->flags & SADB_X_EXT_OLD)
  113                         size = sizeof (struct esp);
  114                 else
  115                         size = sizeof (struct newesp);
  116                 size += sav->tdb_encalgxform->blocksize + 9;
  117                 /*XXX need alg check???*/
  118                 if (sav->tdb_authalgxform != NULL && sav->replay)
  119                         size += ah_hdrsiz(sav);
  120         } else {
  121                 /*
  122                  *   base header size
  123                  * + max iv length for CBC mode
  124                  * + max pad length
  125                  * + sizeof (pad length field)
  126                  * + sizeof (next header field)
  127                  * + max icv supported.
  128                  */
  129                 size = sizeof (struct newesp) + EALG_MAX_BLOCK_LEN + 9 + 16;
  130         }
  131         return size;
  132 }
  133 
  134 /*
  135  * esp_init() is called when an SPI is being set up.
  136  */
  137 static int
  138 esp_init(struct secasvar *sav, struct xformsw *xsp)
  139 {
  140         const struct enc_xform *txform;
  141         struct cryptoini cria, crie;
  142         int keylen;
  143         int error;
  144 
  145         txform = enc_algorithm_lookup(sav->alg_enc);
  146         if (txform == NULL) {
  147                 DPRINTF(("%s: unsupported encryption algorithm %d\n",
  148                         __func__, sav->alg_enc));
  149                 return EINVAL;
  150         }
  151         if (sav->key_enc == NULL) {
  152                 DPRINTF(("%s: no encoding key for %s algorithm\n",
  153                          __func__, txform->name));
  154                 return EINVAL;
  155         }
  156         if ((sav->flags & (SADB_X_EXT_OLD | SADB_X_EXT_IV4B)) ==
  157             SADB_X_EXT_IV4B) {
  158                 DPRINTF(("%s: 4-byte IV not supported with protocol\n",
  159                         __func__));
  160                 return EINVAL;
  161         }
  162 
  163         switch (sav->alg_enc) {
  164         case SADB_EALG_DESCBC:
  165                 if (ratecheck(&deswarn, &ipsec_warn_interval))
  166                         gone_in(13, "DES cipher for IPsec");
  167                 break;
  168         case SADB_EALG_3DESCBC:
  169                 if (ratecheck(&tdeswarn, &ipsec_warn_interval))
  170                         gone_in(13, "3DES cipher for IPsec");
  171                 break;
  172         case SADB_X_EALG_BLOWFISHCBC:
  173                 if (ratecheck(&blfwarn, &ipsec_warn_interval))
  174                         gone_in(13, "Blowfish cipher for IPsec");
  175                 break;
  176         case SADB_X_EALG_CAST128CBC:
  177                 if (ratecheck(&castwarn, &ipsec_warn_interval))
  178                         gone_in(13, "CAST cipher for IPsec");
  179                 break;
  180         case SADB_X_EALG_CAMELLIACBC:
  181                 if (ratecheck(&camelliawarn, &ipsec_warn_interval))
  182                         gone_in(13, "Camellia cipher for IPsec");
  183                 break;
  184         }
  185 
  186         /* subtract off the salt, RFC4106, 8.1 and RFC3686, 5.1 */
  187         keylen = _KEYLEN(sav->key_enc) - SAV_ISCTRORGCM(sav) * 4;
  188         if (txform->minkey > keylen || keylen > txform->maxkey) {
  189                 DPRINTF(("%s: invalid key length %u, must be in the range "
  190                         "[%u..%u] for algorithm %s\n", __func__,
  191                         keylen, txform->minkey, txform->maxkey,
  192                         txform->name));
  193                 return EINVAL;
  194         }
  195 
  196         if (SAV_ISCTRORGCM(sav))
  197                 sav->ivlen = 8; /* RFC4106 3.1 and RFC3686 3.1 */
  198         else
  199                 sav->ivlen = txform->ivsize;
  200 
  201         /*
  202          * Setup AH-related state.
  203          */
  204         if (sav->alg_auth != 0) {
  205                 error = ah_init0(sav, xsp, &cria);
  206                 if (error)
  207                         return error;
  208         }
  209 
  210         /* NB: override anything set in ah_init0 */
  211         sav->tdb_xform = xsp;
  212         sav->tdb_encalgxform = txform;
  213 
  214         /*
  215          * Whenever AES-GCM is used for encryption, one
  216          * of the AES authentication algorithms is chosen
  217          * as well, based on the key size.
  218          */
  219         if (sav->alg_enc == SADB_X_EALG_AESGCM16) {
  220                 switch (keylen) {
  221                 case AES_128_GMAC_KEY_LEN:
  222                         sav->alg_auth = SADB_X_AALG_AES128GMAC;
  223                         sav->tdb_authalgxform = &auth_hash_nist_gmac_aes_128;
  224                         break;
  225                 case AES_192_GMAC_KEY_LEN:
  226                         sav->alg_auth = SADB_X_AALG_AES192GMAC;
  227                         sav->tdb_authalgxform = &auth_hash_nist_gmac_aes_192;
  228                         break;
  229                 case AES_256_GMAC_KEY_LEN:
  230                         sav->alg_auth = SADB_X_AALG_AES256GMAC;
  231                         sav->tdb_authalgxform = &auth_hash_nist_gmac_aes_256;
  232                         break;
  233                 default:
  234                         DPRINTF(("%s: invalid key length %u"
  235                                  "for algorithm %s\n", __func__,
  236                                  keylen, txform->name));
  237                         return EINVAL;
  238                 }
  239                 bzero(&cria, sizeof(cria));
  240                 cria.cri_alg = sav->tdb_authalgxform->type;
  241                 cria.cri_key = sav->key_enc->key_data;
  242                 cria.cri_klen = _KEYBITS(sav->key_enc) - SAV_ISGCM(sav) * 32;
  243         }
  244 
  245         /* Initialize crypto session. */
  246         bzero(&crie, sizeof(crie));
  247         crie.cri_alg = sav->tdb_encalgxform->type;
  248         crie.cri_key = sav->key_enc->key_data;
  249         crie.cri_klen = _KEYBITS(sav->key_enc) - SAV_ISCTRORGCM(sav) * 32;
  250 
  251         if (sav->tdb_authalgxform && sav->tdb_encalgxform) {
  252                 /* init both auth & enc */
  253                 crie.cri_next = &cria;
  254                 error = crypto_newsession(&sav->tdb_cryptoid,
  255                                           &crie, V_crypto_support);
  256         } else if (sav->tdb_encalgxform) {
  257                 error = crypto_newsession(&sav->tdb_cryptoid,
  258                                           &crie, V_crypto_support);
  259         } else if (sav->tdb_authalgxform) {
  260                 error = crypto_newsession(&sav->tdb_cryptoid,
  261                                           &cria, V_crypto_support);
  262         } else {
  263                 /* XXX cannot happen? */
  264                 DPRINTF(("%s: no encoding OR authentication xform!\n",
  265                         __func__));
  266                 error = EINVAL;
  267         }
  268         return error;
  269 }
  270 
  271 /*
  272  * Paranoia.
  273  */
  274 static int
  275 esp_zeroize(struct secasvar *sav)
  276 {
  277         /* NB: ah_zerorize free's the crypto session state */
  278         int error = ah_zeroize(sav);
  279 
  280         if (sav->key_enc)
  281                 bzero(sav->key_enc->key_data, _KEYLEN(sav->key_enc));
  282         sav->tdb_encalgxform = NULL;
  283         sav->tdb_xform = NULL;
  284         return error;
  285 }
  286 
  287 /*
  288  * ESP input processing, called (eventually) through the protocol switch.
  289  */
  290 static int
  291 esp_input(struct mbuf *m, struct secasvar *sav, int skip, int protoff)
  292 {
  293         IPSEC_DEBUG_DECLARE(char buf[128]);
  294         const struct auth_hash *esph;
  295         const struct enc_xform *espx;
  296         struct xform_data *xd;
  297         struct cryptodesc *crde;
  298         struct cryptop *crp;
  299         struct newesp *esp;
  300         uint8_t *ivp;
  301         crypto_session_t cryptoid;
  302         int alen, error, hlen, plen;
  303 
  304         IPSEC_ASSERT(sav != NULL, ("null SA"));
  305         IPSEC_ASSERT(sav->tdb_encalgxform != NULL, ("null encoding xform"));
  306 
  307         error = EINVAL;
  308         /* Valid IP Packet length ? */
  309         if ( (skip&3) || (m->m_pkthdr.len&3) ){
  310                 DPRINTF(("%s: misaligned packet, skip %u pkt len %u",
  311                                 __func__, skip, m->m_pkthdr.len));
  312                 ESPSTAT_INC(esps_badilen);
  313                 goto bad;
  314         }
  315 
  316         if (m->m_len < skip + sizeof(*esp)) {
  317                 m = m_pullup(m, skip + sizeof(*esp));
  318                 if (m == NULL) {
  319                         DPRINTF(("%s: cannot pullup header\n", __func__));
  320                         ESPSTAT_INC(esps_hdrops);       /*XXX*/
  321                         error = ENOBUFS;
  322                         goto bad;
  323                 }
  324         }
  325         esp = (struct newesp *)(mtod(m, caddr_t) + skip);
  326 
  327         esph = sav->tdb_authalgxform;
  328         espx = sav->tdb_encalgxform;
  329 
  330         /* Determine the ESP header and auth length */
  331         if (sav->flags & SADB_X_EXT_OLD)
  332                 hlen = sizeof (struct esp) + sav->ivlen;
  333         else
  334                 hlen = sizeof (struct newesp) + sav->ivlen;
  335 
  336         alen = xform_ah_authsize(esph);
  337 
  338         /*
  339          * Verify payload length is multiple of encryption algorithm
  340          * block size.
  341          *
  342          * NB: This works for the null algorithm because the blocksize
  343          *     is 4 and all packets must be 4-byte aligned regardless
  344          *     of the algorithm.
  345          */
  346         plen = m->m_pkthdr.len - (skip + hlen + alen);
  347         if ((plen & (espx->blocksize - 1)) || (plen <= 0)) {
  348                 DPRINTF(("%s: payload of %d octets not a multiple of %d octets,"
  349                     "  SA %s/%08lx\n", __func__, plen, espx->blocksize,
  350                     ipsec_address(&sav->sah->saidx.dst, buf, sizeof(buf)),
  351                     (u_long)ntohl(sav->spi)));
  352                 ESPSTAT_INC(esps_badilen);
  353                 goto bad;
  354         }
  355 
  356         /*
  357          * Check sequence number.
  358          */
  359         SECASVAR_LOCK(sav);
  360         if (esph != NULL && sav->replay != NULL && sav->replay->wsize != 0) {
  361                 if (ipsec_chkreplay(ntohl(esp->esp_seq), sav) == 0) {
  362                         SECASVAR_UNLOCK(sav);
  363                         DPRINTF(("%s: packet replay check for %s\n", __func__,
  364                             ipsec_sa2str(sav, buf, sizeof(buf))));
  365                         ESPSTAT_INC(esps_replay);
  366                         error = EACCES;
  367                         goto bad;
  368                 }
  369         }
  370         cryptoid = sav->tdb_cryptoid;
  371         SECASVAR_UNLOCK(sav);
  372 
  373         /* Update the counters */
  374         ESPSTAT_ADD(esps_ibytes, m->m_pkthdr.len - (skip + hlen + alen));
  375 
  376         /* Get crypto descriptors */
  377         crp = crypto_getreq(esph && espx ? 2 : 1);
  378         if (crp == NULL) {
  379                 DPRINTF(("%s: failed to acquire crypto descriptors\n",
  380                         __func__));
  381                 ESPSTAT_INC(esps_crypto);
  382                 error = ENOBUFS;
  383                 goto bad;
  384         }
  385 
  386         /* Get IPsec-specific opaque pointer */
  387         xd = malloc(sizeof(*xd) + alen, M_XDATA, M_NOWAIT | M_ZERO);
  388         if (xd == NULL) {
  389                 DPRINTF(("%s: failed to allocate xform_data\n", __func__));
  390                 ESPSTAT_INC(esps_crypto);
  391                 crypto_freereq(crp);
  392                 error = ENOBUFS;
  393                 goto bad;
  394         }
  395 
  396         if (esph != NULL) {
  397                 struct cryptodesc *crda = crp->crp_desc;
  398 
  399                 IPSEC_ASSERT(crda != NULL, ("null ah crypto descriptor"));
  400 
  401                 /* Authentication descriptor */
  402                 crda->crd_skip = skip;
  403                 if (SAV_ISGCM(sav))
  404                         crda->crd_len = 8;      /* RFC4106 5, SPI + SN */
  405                 else
  406                         crda->crd_len = m->m_pkthdr.len - (skip + alen);
  407                 crda->crd_inject = m->m_pkthdr.len - alen;
  408 
  409                 crda->crd_alg = esph->type;
  410 
  411                 /* Copy the authenticator */
  412                 m_copydata(m, m->m_pkthdr.len - alen, alen,
  413                     (caddr_t) (xd + 1));
  414 
  415                 /* Chain authentication request */
  416                 crde = crda->crd_next;
  417         } else {
  418                 crde = crp->crp_desc;
  419         }
  420 
  421         /* Crypto operation descriptor */
  422         crp->crp_ilen = m->m_pkthdr.len; /* Total input length */
  423         crp->crp_flags = CRYPTO_F_IMBUF | CRYPTO_F_CBIFSYNC;
  424         if (V_async_crypto)
  425                 crp->crp_flags |= CRYPTO_F_ASYNC | CRYPTO_F_ASYNC_KEEPORDER;
  426         crp->crp_buf = (caddr_t) m;
  427         crp->crp_callback = esp_input_cb;
  428         crp->crp_session = cryptoid;
  429         crp->crp_opaque = (caddr_t) xd;
  430 
  431         /* These are passed as-is to the callback */
  432         xd->sav = sav;
  433         xd->protoff = protoff;
  434         xd->skip = skip;
  435         xd->cryptoid = cryptoid;
  436         xd->vnet = curvnet;
  437 
  438         /* Decryption descriptor */
  439         IPSEC_ASSERT(crde != NULL, ("null esp crypto descriptor"));
  440         crde->crd_skip = skip + hlen;
  441         crde->crd_len = m->m_pkthdr.len - (skip + hlen + alen);
  442         crde->crd_inject = skip + hlen - sav->ivlen;
  443 
  444         if (SAV_ISCTRORGCM(sav)) {
  445                 ivp = &crde->crd_iv[0];
  446 
  447                 /* GCM IV Format: RFC4106 4 */
  448                 /* CTR IV Format: RFC3686 4 */
  449                 /* Salt is last four bytes of key, RFC4106 8.1 */
  450                 /* Nonce is last four bytes of key, RFC3686 5.1 */
  451                 memcpy(ivp, sav->key_enc->key_data +
  452                     _KEYLEN(sav->key_enc) - 4, 4);
  453 
  454                 if (SAV_ISCTR(sav)) {
  455                         /* Initial block counter is 1, RFC3686 4 */
  456                         be32enc(&ivp[sav->ivlen + 4], 1);
  457                 }
  458 
  459                 m_copydata(m, skip + hlen - sav->ivlen, sav->ivlen, &ivp[4]);
  460                 crde->crd_flags |= CRD_F_IV_EXPLICIT;
  461         }
  462 
  463         crde->crd_alg = espx->type;
  464 
  465         return (crypto_dispatch(crp));
  466 bad:
  467         m_freem(m);
  468         key_freesav(&sav);
  469         return (error);
  470 }
  471 
  472 /*
  473  * ESP input callback from the crypto driver.
  474  */
  475 static int
  476 esp_input_cb(struct cryptop *crp)
  477 {
  478         IPSEC_DEBUG_DECLARE(char buf[128]);
  479         u_int8_t lastthree[3], aalg[AH_HMAC_MAXHASHLEN];
  480         const struct auth_hash *esph;
  481         struct mbuf *m;
  482         struct cryptodesc *crd;
  483         struct xform_data *xd;
  484         struct secasvar *sav;
  485         struct secasindex *saidx;
  486         caddr_t ptr;
  487         crypto_session_t cryptoid;
  488         int hlen, skip, protoff, error, alen;
  489 
  490         crd = crp->crp_desc;
  491         IPSEC_ASSERT(crd != NULL, ("null crypto descriptor!"));
  492 
  493         m = (struct mbuf *) crp->crp_buf;
  494         xd = (struct xform_data *) crp->crp_opaque;
  495         CURVNET_SET(xd->vnet);
  496         sav = xd->sav;
  497         skip = xd->skip;
  498         protoff = xd->protoff;
  499         cryptoid = xd->cryptoid;
  500         saidx = &sav->sah->saidx;
  501         esph = sav->tdb_authalgxform;
  502 
  503         /* Check for crypto errors */
  504         if (crp->crp_etype) {
  505                 if (crp->crp_etype == EAGAIN) {
  506                         /* Reset the session ID */
  507                         if (ipsec_updateid(sav, &crp->crp_session, &cryptoid) != 0)
  508                                 crypto_freesession(cryptoid);
  509                         xd->cryptoid = crp->crp_session;
  510                         CURVNET_RESTORE();
  511                         return (crypto_dispatch(crp));
  512                 }
  513                 ESPSTAT_INC(esps_noxform);
  514                 DPRINTF(("%s: crypto error %d\n", __func__, crp->crp_etype));
  515                 error = crp->crp_etype;
  516                 goto bad;
  517         }
  518 
  519         /* Shouldn't happen... */
  520         if (m == NULL) {
  521                 ESPSTAT_INC(esps_crypto);
  522                 DPRINTF(("%s: bogus returned buffer from crypto\n", __func__));
  523                 error = EINVAL;
  524                 goto bad;
  525         }
  526         ESPSTAT_INC(esps_hist[sav->alg_enc]);
  527 
  528         /* If authentication was performed, check now. */
  529         if (esph != NULL) {
  530                 alen = xform_ah_authsize(esph);
  531                 AHSTAT_INC(ahs_hist[sav->alg_auth]);
  532                 /* Copy the authenticator from the packet */
  533                 m_copydata(m, m->m_pkthdr.len - alen, alen, aalg);
  534                 ptr = (caddr_t) (xd + 1);
  535 
  536                 /* Verify authenticator */
  537                 if (timingsafe_bcmp(ptr, aalg, alen) != 0) {
  538                         DPRINTF(("%s: authentication hash mismatch for "
  539                             "packet in SA %s/%08lx\n", __func__,
  540                             ipsec_address(&saidx->dst, buf, sizeof(buf)),
  541                             (u_long) ntohl(sav->spi)));
  542                         ESPSTAT_INC(esps_badauth);
  543                         error = EACCES;
  544                         goto bad;
  545                 }
  546                 m->m_flags |= M_AUTHIPDGM;
  547                 /* Remove trailing authenticator */
  548                 m_adj(m, -alen);
  549         }
  550 
  551         /* Release the crypto descriptors */
  552         free(xd, M_XDATA), xd = NULL;
  553         crypto_freereq(crp), crp = NULL;
  554 
  555         /*
  556          * Packet is now decrypted.
  557          */
  558         m->m_flags |= M_DECRYPTED;
  559 
  560         /*
  561          * Update replay sequence number, if appropriate.
  562          */
  563         if (sav->replay) {
  564                 u_int32_t seq;
  565 
  566                 m_copydata(m, skip + offsetof(struct newesp, esp_seq),
  567                            sizeof (seq), (caddr_t) &seq);
  568                 SECASVAR_LOCK(sav);
  569                 if (ipsec_updatereplay(ntohl(seq), sav)) {
  570                         SECASVAR_UNLOCK(sav);
  571                         DPRINTF(("%s: packet replay check for %s\n", __func__,
  572                             ipsec_sa2str(sav, buf, sizeof(buf))));
  573                         ESPSTAT_INC(esps_replay);
  574                         error = EACCES;
  575                         goto bad;
  576                 }
  577                 SECASVAR_UNLOCK(sav);
  578         }
  579 
  580         /* Determine the ESP header length */
  581         if (sav->flags & SADB_X_EXT_OLD)
  582                 hlen = sizeof (struct esp) + sav->ivlen;
  583         else
  584                 hlen = sizeof (struct newesp) + sav->ivlen;
  585 
  586         /* Remove the ESP header and IV from the mbuf. */
  587         error = m_striphdr(m, skip, hlen);
  588         if (error) {
  589                 ESPSTAT_INC(esps_hdrops);
  590                 DPRINTF(("%s: bad mbuf chain, SA %s/%08lx\n", __func__,
  591                     ipsec_address(&sav->sah->saidx.dst, buf, sizeof(buf)),
  592                     (u_long) ntohl(sav->spi)));
  593                 goto bad;
  594         }
  595 
  596         /* Save the last three bytes of decrypted data */
  597         m_copydata(m, m->m_pkthdr.len - 3, 3, lastthree);
  598 
  599         /* Verify pad length */
  600         if (lastthree[1] + 2 > m->m_pkthdr.len - skip) {
  601                 ESPSTAT_INC(esps_badilen);
  602                 DPRINTF(("%s: invalid padding length %d for %u byte packet "
  603                     "in SA %s/%08lx\n", __func__, lastthree[1],
  604                     m->m_pkthdr.len - skip,
  605                     ipsec_address(&sav->sah->saidx.dst, buf, sizeof(buf)),
  606                     (u_long) ntohl(sav->spi)));
  607                 error = EINVAL;
  608                 goto bad;
  609         }
  610 
  611         /* Verify correct decryption by checking the last padding bytes */
  612         if ((sav->flags & SADB_X_EXT_PMASK) != SADB_X_EXT_PRAND) {
  613                 if (lastthree[1] != lastthree[0] && lastthree[1] != 0) {
  614                         ESPSTAT_INC(esps_badenc);
  615                         DPRINTF(("%s: decryption failed for packet in "
  616                             "SA %s/%08lx\n", __func__, ipsec_address(
  617                             &sav->sah->saidx.dst, buf, sizeof(buf)),
  618                             (u_long) ntohl(sav->spi)));
  619                         error = EINVAL;
  620                         goto bad;
  621                 }
  622         }
  623 
  624         /*
  625          * RFC4303 2.6:
  626          * Silently drop packet if next header field is IPPROTO_NONE.
  627          */
  628         if (lastthree[2] == IPPROTO_NONE)
  629                 goto bad;
  630 
  631         /* Trim the mbuf chain to remove trailing authenticator and padding */
  632         m_adj(m, -(lastthree[1] + 2));
  633 
  634         /* Restore the Next Protocol field */
  635         m_copyback(m, protoff, sizeof (u_int8_t), lastthree + 2);
  636 
  637         switch (saidx->dst.sa.sa_family) {
  638 #ifdef INET6
  639         case AF_INET6:
  640                 error = ipsec6_common_input_cb(m, sav, skip, protoff);
  641                 break;
  642 #endif
  643 #ifdef INET
  644         case AF_INET:
  645                 error = ipsec4_common_input_cb(m, sav, skip, protoff);
  646                 break;
  647 #endif
  648         default:
  649                 panic("%s: Unexpected address family: %d saidx=%p", __func__,
  650                     saidx->dst.sa.sa_family, saidx);
  651         }
  652         CURVNET_RESTORE();
  653         return error;
  654 bad:
  655         CURVNET_RESTORE();
  656         if (sav != NULL)
  657                 key_freesav(&sav);
  658         if (m != NULL)
  659                 m_freem(m);
  660         if (xd != NULL)
  661                 free(xd, M_XDATA);
  662         if (crp != NULL)
  663                 crypto_freereq(crp);
  664         return error;
  665 }
  666 /*
  667  * ESP output routine, called by ipsec[46]_perform_request().
  668  */
  669 static int
  670 esp_output(struct mbuf *m, struct secpolicy *sp, struct secasvar *sav,
  671     u_int idx, int skip, int protoff)
  672 {
  673         IPSEC_DEBUG_DECLARE(char buf[IPSEC_ADDRSTRLEN]);
  674         struct cryptodesc *crde = NULL, *crda = NULL;
  675         struct cryptop *crp;
  676         const struct auth_hash *esph;
  677         const struct enc_xform *espx;
  678         struct mbuf *mo = NULL;
  679         struct xform_data *xd;
  680         struct secasindex *saidx;
  681         unsigned char *pad;
  682         uint8_t *ivp;
  683         uint64_t cntr;
  684         crypto_session_t cryptoid;
  685         int hlen, rlen, padding, blks, alen, i, roff;
  686         int error, maxpacketsize;
  687         uint8_t prot;
  688 
  689         IPSEC_ASSERT(sav != NULL, ("null SA"));
  690         esph = sav->tdb_authalgxform;
  691         espx = sav->tdb_encalgxform;
  692         IPSEC_ASSERT(espx != NULL, ("null encoding xform"));
  693 
  694         if (sav->flags & SADB_X_EXT_OLD)
  695                 hlen = sizeof (struct esp) + sav->ivlen;
  696         else
  697                 hlen = sizeof (struct newesp) + sav->ivlen;
  698 
  699         rlen = m->m_pkthdr.len - skip;  /* Raw payload length. */
  700         /*
  701          * RFC4303 2.4 Requires 4 byte alignment.
  702          */
  703         blks = MAX(4, espx->blocksize);         /* Cipher blocksize */
  704 
  705         /* XXX clamp padding length a la KAME??? */
  706         padding = ((blks - ((rlen + 2) % blks)) % blks) + 2;
  707 
  708         alen = xform_ah_authsize(esph);
  709 
  710         ESPSTAT_INC(esps_output);
  711 
  712         saidx = &sav->sah->saidx;
  713         /* Check for maximum packet size violations. */
  714         switch (saidx->dst.sa.sa_family) {
  715 #ifdef INET
  716         case AF_INET:
  717                 maxpacketsize = IP_MAXPACKET;
  718                 break;
  719 #endif /* INET */
  720 #ifdef INET6
  721         case AF_INET6:
  722                 maxpacketsize = IPV6_MAXPACKET;
  723                 break;
  724 #endif /* INET6 */
  725         default:
  726                 DPRINTF(("%s: unknown/unsupported protocol "
  727                     "family %d, SA %s/%08lx\n", __func__,
  728                     saidx->dst.sa.sa_family, ipsec_address(&saidx->dst,
  729                         buf, sizeof(buf)), (u_long) ntohl(sav->spi)));
  730                 ESPSTAT_INC(esps_nopf);
  731                 error = EPFNOSUPPORT;
  732                 goto bad;
  733         }
  734         /*
  735         DPRINTF(("%s: skip %d hlen %d rlen %d padding %d alen %d blksd %d\n",
  736                 __func__, skip, hlen, rlen, padding, alen, blks)); */
  737         if (skip + hlen + rlen + padding + alen > maxpacketsize) {
  738                 DPRINTF(("%s: packet in SA %s/%08lx got too big "
  739                     "(len %u, max len %u)\n", __func__,
  740                     ipsec_address(&saidx->dst, buf, sizeof(buf)),
  741                     (u_long) ntohl(sav->spi),
  742                     skip + hlen + rlen + padding + alen, maxpacketsize));
  743                 ESPSTAT_INC(esps_toobig);
  744                 error = EMSGSIZE;
  745                 goto bad;
  746         }
  747 
  748         /* Update the counters. */
  749         ESPSTAT_ADD(esps_obytes, m->m_pkthdr.len - skip);
  750 
  751         m = m_unshare(m, M_NOWAIT);
  752         if (m == NULL) {
  753                 DPRINTF(("%s: cannot clone mbuf chain, SA %s/%08lx\n", __func__,
  754                     ipsec_address(&saidx->dst, buf, sizeof(buf)),
  755                     (u_long) ntohl(sav->spi)));
  756                 ESPSTAT_INC(esps_hdrops);
  757                 error = ENOBUFS;
  758                 goto bad;
  759         }
  760 
  761         /* Inject ESP header. */
  762         mo = m_makespace(m, skip, hlen, &roff);
  763         if (mo == NULL) {
  764                 DPRINTF(("%s: %u byte ESP hdr inject failed for SA %s/%08lx\n",
  765                     __func__, hlen, ipsec_address(&saidx->dst, buf,
  766                     sizeof(buf)), (u_long) ntohl(sav->spi)));
  767                 ESPSTAT_INC(esps_hdrops);       /* XXX diffs from openbsd */
  768                 error = ENOBUFS;
  769                 goto bad;
  770         }
  771 
  772         /* Initialize ESP header. */
  773         bcopy((caddr_t) &sav->spi, mtod(mo, caddr_t) + roff,
  774             sizeof(uint32_t));
  775         SECASVAR_LOCK(sav);
  776         if (sav->replay) {
  777                 uint32_t replay;
  778 
  779 #ifdef REGRESSION
  780                 /* Emulate replay attack when ipsec_replay is TRUE. */
  781                 if (!V_ipsec_replay)
  782 #endif
  783                         sav->replay->count++;
  784                 replay = htonl(sav->replay->count);
  785 
  786                 bcopy((caddr_t) &replay, mtod(mo, caddr_t) + roff +
  787                     sizeof(uint32_t), sizeof(uint32_t));
  788         }
  789         cryptoid = sav->tdb_cryptoid;
  790         if (SAV_ISCTRORGCM(sav))
  791                 cntr = sav->cntr++;
  792         SECASVAR_UNLOCK(sav);
  793 
  794         /*
  795          * Add padding -- better to do it ourselves than use the crypto engine,
  796          * although if/when we support compression, we'd have to do that.
  797          */
  798         pad = (u_char *) m_pad(m, padding + alen);
  799         if (pad == NULL) {
  800                 DPRINTF(("%s: m_pad failed for SA %s/%08lx\n", __func__,
  801                     ipsec_address(&saidx->dst, buf, sizeof(buf)),
  802                     (u_long) ntohl(sav->spi)));
  803                 m = NULL;               /* NB: free'd by m_pad */
  804                 error = ENOBUFS;
  805                 goto bad;
  806         }
  807 
  808         /*
  809          * Add padding: random, zero, or self-describing.
  810          * XXX catch unexpected setting
  811          */
  812         switch (sav->flags & SADB_X_EXT_PMASK) {
  813         case SADB_X_EXT_PRAND:
  814                 (void) read_random(pad, padding - 2);
  815                 break;
  816         case SADB_X_EXT_PZERO:
  817                 bzero(pad, padding - 2);
  818                 break;
  819         case SADB_X_EXT_PSEQ:
  820                 for (i = 0; i < padding - 2; i++)
  821                         pad[i] = i+1;
  822                 break;
  823         }
  824 
  825         /* Fix padding length and Next Protocol in padding itself. */
  826         pad[padding - 2] = padding - 2;
  827         m_copydata(m, protoff, sizeof(u_int8_t), pad + padding - 1);
  828 
  829         /* Fix Next Protocol in IPv4/IPv6 header. */
  830         prot = IPPROTO_ESP;
  831         m_copyback(m, protoff, sizeof(u_int8_t), (u_char *) &prot);
  832 
  833         /* Get crypto descriptors. */
  834         crp = crypto_getreq(esph != NULL ? 2 : 1);
  835         if (crp == NULL) {
  836                 DPRINTF(("%s: failed to acquire crypto descriptors\n",
  837                         __func__));
  838                 ESPSTAT_INC(esps_crypto);
  839                 error = ENOBUFS;
  840                 goto bad;
  841         }
  842 
  843         /* IPsec-specific opaque crypto info. */
  844         xd =  malloc(sizeof(struct xform_data), M_XDATA, M_NOWAIT | M_ZERO);
  845         if (xd == NULL) {
  846                 crypto_freereq(crp);
  847                 DPRINTF(("%s: failed to allocate xform_data\n", __func__));
  848                 ESPSTAT_INC(esps_crypto);
  849                 error = ENOBUFS;
  850                 goto bad;
  851         }
  852 
  853         crde = crp->crp_desc;
  854         crda = crde->crd_next;
  855 
  856         /* Encryption descriptor. */
  857         crde->crd_skip = skip + hlen;
  858         crde->crd_len = m->m_pkthdr.len - (skip + hlen + alen);
  859         crde->crd_flags = CRD_F_ENCRYPT;
  860         crde->crd_inject = skip + hlen - sav->ivlen;
  861 
  862         /* Encryption operation. */
  863         crde->crd_alg = espx->type;
  864         if (SAV_ISCTRORGCM(sav)) {
  865                 ivp = &crde->crd_iv[0];
  866 
  867                 /* GCM IV Format: RFC4106 4 */
  868                 /* CTR IV Format: RFC3686 4 */
  869                 /* Salt is last four bytes of key, RFC4106 8.1 */
  870                 /* Nonce is last four bytes of key, RFC3686 5.1 */
  871                 memcpy(ivp, sav->key_enc->key_data +
  872                     _KEYLEN(sav->key_enc) - 4, 4);
  873                 be64enc(&ivp[4], cntr);
  874                 if (SAV_ISCTR(sav)) {
  875                         /* Initial block counter is 1, RFC3686 4 */
  876                         /* XXXAE: should we use this only for first packet? */
  877                         be32enc(&ivp[sav->ivlen + 4], 1);
  878                 }
  879 
  880                 m_copyback(m, skip + hlen - sav->ivlen, sav->ivlen, &ivp[4]);
  881                 crde->crd_flags |= CRD_F_IV_EXPLICIT|CRD_F_IV_PRESENT;
  882         }
  883 
  884         /* Callback parameters */
  885         xd->sp = sp;
  886         xd->sav = sav;
  887         xd->idx = idx;
  888         xd->cryptoid = cryptoid;
  889         xd->vnet = curvnet;
  890 
  891         /* Crypto operation descriptor. */
  892         crp->crp_ilen = m->m_pkthdr.len; /* Total input length. */
  893         crp->crp_flags = CRYPTO_F_IMBUF | CRYPTO_F_CBIFSYNC;
  894         if (V_async_crypto)
  895                 crp->crp_flags |= CRYPTO_F_ASYNC | CRYPTO_F_ASYNC_KEEPORDER;
  896         crp->crp_buf = (caddr_t) m;
  897         crp->crp_callback = esp_output_cb;
  898         crp->crp_opaque = (caddr_t) xd;
  899         crp->crp_session = cryptoid;
  900 
  901         if (esph) {
  902                 /* Authentication descriptor. */
  903                 crda->crd_alg = esph->type;
  904                 crda->crd_skip = skip;
  905                 if (SAV_ISGCM(sav))
  906                         crda->crd_len = 8;      /* RFC4106 5, SPI + SN */
  907                 else
  908                         crda->crd_len = m->m_pkthdr.len - (skip + alen);
  909                 crda->crd_inject = m->m_pkthdr.len - alen;
  910         }
  911 
  912         return crypto_dispatch(crp);
  913 bad:
  914         if (m)
  915                 m_freem(m);
  916         key_freesav(&sav);
  917         key_freesp(&sp);
  918         return (error);
  919 }
  920 /*
  921  * ESP output callback from the crypto driver.
  922  */
  923 static int
  924 esp_output_cb(struct cryptop *crp)
  925 {
  926         struct xform_data *xd;
  927         struct secpolicy *sp;
  928         struct secasvar *sav;
  929         struct mbuf *m;
  930         crypto_session_t cryptoid;
  931         u_int idx;
  932         int error;
  933 
  934         xd = (struct xform_data *) crp->crp_opaque;
  935         CURVNET_SET(xd->vnet);
  936         m = (struct mbuf *) crp->crp_buf;
  937         sp = xd->sp;
  938         sav = xd->sav;
  939         idx = xd->idx;
  940         cryptoid = xd->cryptoid;
  941 
  942         /* Check for crypto errors. */
  943         if (crp->crp_etype) {
  944                 if (crp->crp_etype == EAGAIN) {
  945                         /* Reset the session ID */
  946                         if (ipsec_updateid(sav, &crp->crp_session, &cryptoid) != 0)
  947                                 crypto_freesession(cryptoid);
  948                         xd->cryptoid = crp->crp_session;
  949                         CURVNET_RESTORE();
  950                         return (crypto_dispatch(crp));
  951                 }
  952                 ESPSTAT_INC(esps_noxform);
  953                 DPRINTF(("%s: crypto error %d\n", __func__, crp->crp_etype));
  954                 error = crp->crp_etype;
  955                 m_freem(m);
  956                 goto bad;
  957         }
  958 
  959         /* Shouldn't happen... */
  960         if (m == NULL) {
  961                 ESPSTAT_INC(esps_crypto);
  962                 DPRINTF(("%s: bogus returned buffer from crypto\n", __func__));
  963                 error = EINVAL;
  964                 goto bad;
  965         }
  966         free(xd, M_XDATA);
  967         crypto_freereq(crp);
  968         ESPSTAT_INC(esps_hist[sav->alg_enc]);
  969         if (sav->tdb_authalgxform != NULL)
  970                 AHSTAT_INC(ahs_hist[sav->alg_auth]);
  971 
  972 #ifdef REGRESSION
  973         /* Emulate man-in-the-middle attack when ipsec_integrity is TRUE. */
  974         if (V_ipsec_integrity) {
  975                 static unsigned char ipseczeroes[AH_HMAC_MAXHASHLEN];
  976                 const struct auth_hash *esph;
  977 
  978                 /*
  979                  * Corrupt HMAC if we want to test integrity verification of
  980                  * the other side.
  981                  */
  982                 esph = sav->tdb_authalgxform;
  983                 if (esph !=  NULL) {
  984                         int alen;
  985 
  986                         alen = xform_ah_authsize(esph);
  987                         m_copyback(m, m->m_pkthdr.len - alen,
  988                             alen, ipseczeroes);
  989                 }
  990         }
  991 #endif
  992 
  993         /* NB: m is reclaimed by ipsec_process_done. */
  994         error = ipsec_process_done(m, sp, sav, idx);
  995         CURVNET_RESTORE();
  996         return (error);
  997 bad:
  998         CURVNET_RESTORE();
  999         free(xd, M_XDATA);
 1000         crypto_freereq(crp);
 1001         key_freesav(&sav);
 1002         key_freesp(&sp);
 1003         return (error);
 1004 }
 1005 
 1006 static struct xformsw esp_xformsw = {
 1007         .xf_type =      XF_ESP,
 1008         .xf_name =      "IPsec ESP",
 1009         .xf_init =      esp_init,
 1010         .xf_zeroize =   esp_zeroize,
 1011         .xf_input =     esp_input,
 1012         .xf_output =    esp_output,
 1013 };
 1014 
 1015 SYSINIT(esp_xform_init, SI_SUB_PROTO_DOMAIN, SI_ORDER_MIDDLE,
 1016     xform_attach, &esp_xformsw);
 1017 SYSUNINIT(esp_xform_uninit, SI_SUB_PROTO_DOMAIN, SI_ORDER_MIDDLE,
 1018     xform_detach, &esp_xformsw);

Cache object: ec4198c2d82b6354bc7e956ac1b88444


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