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 360721 2020-05-06 23:23:22Z 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 
   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 struct timeval deswarn, blfwarn, castwarn, camelliawarn, tdeswarn;
   98 
   99 static int esp_input_cb(struct cryptop *op);
  100 static int esp_output_cb(struct cryptop *crp);
  101 
  102 size_t
  103 esp_hdrsiz(struct secasvar *sav)
  104 {
  105         size_t size;
  106 
  107         if (sav != NULL) {
  108                 /*XXX not right for null algorithm--does it matter??*/
  109                 IPSEC_ASSERT(sav->tdb_encalgxform != NULL,
  110                         ("SA with null xform"));
  111                 if (sav->flags & SADB_X_EXT_OLD)
  112                         size = sizeof (struct esp);
  113                 else
  114                         size = sizeof (struct newesp);
  115                 size += sav->tdb_encalgxform->blocksize + 9;
  116                 /*XXX need alg check???*/
  117                 if (sav->tdb_authalgxform != NULL && sav->replay)
  118                         size += ah_hdrsiz(sav);
  119         } else {
  120                 /*
  121                  *   base header size
  122                  * + max iv length for CBC mode
  123                  * + max pad length
  124                  * + sizeof (pad length field)
  125                  * + sizeof (next header field)
  126                  * + max icv supported.
  127                  */
  128                 size = sizeof (struct newesp) + EALG_MAX_BLOCK_LEN + 9 + 16;
  129         }
  130         return size;
  131 }
  132 
  133 /*
  134  * esp_init() is called when an SPI is being set up.
  135  */
  136 static int
  137 esp_init(struct secasvar *sav, struct xformsw *xsp)
  138 {
  139         const struct enc_xform *txform;
  140         struct cryptoini cria, crie;
  141         int keylen;
  142         int error;
  143 
  144         txform = enc_algorithm_lookup(sav->alg_enc);
  145         if (txform == NULL) {
  146                 DPRINTF(("%s: unsupported encryption algorithm %d\n",
  147                         __func__, sav->alg_enc));
  148                 return EINVAL;
  149         }
  150         if (sav->key_enc == NULL) {
  151                 DPRINTF(("%s: no encoding key for %s algorithm\n",
  152                          __func__, txform->name));
  153                 return EINVAL;
  154         }
  155         if ((sav->flags & (SADB_X_EXT_OLD | SADB_X_EXT_IV4B)) ==
  156             SADB_X_EXT_IV4B) {
  157                 DPRINTF(("%s: 4-byte IV not supported with protocol\n",
  158                         __func__));
  159                 return EINVAL;
  160         }
  161 
  162         switch (sav->alg_enc) {
  163         case SADB_EALG_DESCBC:
  164                 if (ratecheck(&deswarn, &ipsec_warn_interval))
  165                         gone_in(13, "DES cipher for IPsec");
  166                 break;
  167         case SADB_EALG_3DESCBC:
  168                 if (ratecheck(&tdeswarn, &ipsec_warn_interval))
  169                         gone_in(13, "3DES cipher for IPsec");
  170                 break;
  171         case SADB_X_EALG_BLOWFISHCBC:
  172                 if (ratecheck(&blfwarn, &ipsec_warn_interval))
  173                         gone_in(13, "Blowfish cipher for IPsec");
  174                 break;
  175         case SADB_X_EALG_CAST128CBC:
  176                 if (ratecheck(&castwarn, &ipsec_warn_interval))
  177                         gone_in(13, "CAST cipher for IPsec");
  178                 break;
  179         case SADB_X_EALG_CAMELLIACBC:
  180                 if (ratecheck(&camelliawarn, &ipsec_warn_interval))
  181                         gone_in(13, "Camellia cipher for IPsec");
  182                 break;
  183         }
  184 
  185         /* subtract off the salt, RFC4106, 8.1 and RFC3686, 5.1 */
  186         keylen = _KEYLEN(sav->key_enc) - SAV_ISCTRORGCM(sav) * 4;
  187         if (txform->minkey > keylen || keylen > txform->maxkey) {
  188                 DPRINTF(("%s: invalid key length %u, must be in the range "
  189                         "[%u..%u] for algorithm %s\n", __func__,
  190                         keylen, txform->minkey, txform->maxkey,
  191                         txform->name));
  192                 return EINVAL;
  193         }
  194 
  195         if (SAV_ISCTRORGCM(sav))
  196                 sav->ivlen = 8; /* RFC4106 3.1 and RFC3686 3.1 */
  197         else
  198                 sav->ivlen = txform->ivsize;
  199 
  200         /*
  201          * Setup AH-related state.
  202          */
  203         if (sav->alg_auth != 0) {
  204                 error = ah_init0(sav, xsp, &cria);
  205                 if (error)
  206                         return error;
  207         }
  208 
  209         /* NB: override anything set in ah_init0 */
  210         sav->tdb_xform = xsp;
  211         sav->tdb_encalgxform = txform;
  212 
  213         /*
  214          * Whenever AES-GCM is used for encryption, one
  215          * of the AES authentication algorithms is chosen
  216          * as well, based on the key size.
  217          */
  218         if (sav->alg_enc == SADB_X_EALG_AESGCM16) {
  219                 switch (keylen) {
  220                 case AES_128_GMAC_KEY_LEN:
  221                         sav->alg_auth = SADB_X_AALG_AES128GMAC;
  222                         sav->tdb_authalgxform = &auth_hash_nist_gmac_aes_128;
  223                         break;
  224                 case AES_192_GMAC_KEY_LEN:
  225                         sav->alg_auth = SADB_X_AALG_AES192GMAC;
  226                         sav->tdb_authalgxform = &auth_hash_nist_gmac_aes_192;
  227                         break;
  228                 case AES_256_GMAC_KEY_LEN:
  229                         sav->alg_auth = SADB_X_AALG_AES256GMAC;
  230                         sav->tdb_authalgxform = &auth_hash_nist_gmac_aes_256;
  231                         break;
  232                 default:
  233                         DPRINTF(("%s: invalid key length %u"
  234                                  "for algorithm %s\n", __func__,
  235                                  keylen, txform->name));
  236                         return EINVAL;
  237                 }
  238                 bzero(&cria, sizeof(cria));
  239                 cria.cri_alg = sav->tdb_authalgxform->type;
  240                 cria.cri_key = sav->key_enc->key_data;
  241                 cria.cri_klen = _KEYBITS(sav->key_enc) - SAV_ISGCM(sav) * 32;
  242         }
  243 
  244         /* Initialize crypto session. */
  245         bzero(&crie, sizeof(crie));
  246         crie.cri_alg = sav->tdb_encalgxform->type;
  247         crie.cri_key = sav->key_enc->key_data;
  248         crie.cri_klen = _KEYBITS(sav->key_enc) - SAV_ISCTRORGCM(sav) * 32;
  249 
  250         if (sav->tdb_authalgxform && sav->tdb_encalgxform) {
  251                 /* init both auth & enc */
  252                 crie.cri_next = &cria;
  253                 error = crypto_newsession(&sav->tdb_cryptoid,
  254                                           &crie, V_crypto_support);
  255         } else if (sav->tdb_encalgxform) {
  256                 error = crypto_newsession(&sav->tdb_cryptoid,
  257                                           &crie, V_crypto_support);
  258         } else if (sav->tdb_authalgxform) {
  259                 error = crypto_newsession(&sav->tdb_cryptoid,
  260                                           &cria, V_crypto_support);
  261         } else {
  262                 /* XXX cannot happen? */
  263                 DPRINTF(("%s: no encoding OR authentication xform!\n",
  264                         __func__));
  265                 error = EINVAL;
  266         }
  267         return error;
  268 }
  269 
  270 /*
  271  * Paranoia.
  272  */
  273 static int
  274 esp_zeroize(struct secasvar *sav)
  275 {
  276         /* NB: ah_zerorize free's the crypto session state */
  277         int error = ah_zeroize(sav);
  278 
  279         if (sav->key_enc)
  280                 bzero(sav->key_enc->key_data, _KEYLEN(sav->key_enc));
  281         sav->tdb_encalgxform = NULL;
  282         sav->tdb_xform = NULL;
  283         return error;
  284 }
  285 
  286 /*
  287  * ESP input processing, called (eventually) through the protocol switch.
  288  */
  289 static int
  290 esp_input(struct mbuf *m, struct secasvar *sav, int skip, int protoff)
  291 {
  292         IPSEC_DEBUG_DECLARE(char buf[128]);
  293         const struct auth_hash *esph;
  294         const struct enc_xform *espx;
  295         struct xform_data *xd;
  296         struct cryptodesc *crde;
  297         struct cryptop *crp;
  298         struct newesp *esp;
  299         uint8_t *ivp;
  300         crypto_session_t cryptoid;
  301         int alen, error, hlen, plen;
  302 
  303         IPSEC_ASSERT(sav != NULL, ("null SA"));
  304         IPSEC_ASSERT(sav->tdb_encalgxform != NULL, ("null encoding xform"));
  305 
  306         error = EINVAL;
  307         /* Valid IP Packet length ? */
  308         if ( (skip&3) || (m->m_pkthdr.len&3) ){
  309                 DPRINTF(("%s: misaligned packet, skip %u pkt len %u",
  310                                 __func__, skip, m->m_pkthdr.len));
  311                 ESPSTAT_INC(esps_badilen);
  312                 goto bad;
  313         }
  314 
  315         if (m->m_len < skip + sizeof(*esp)) {
  316                 m = m_pullup(m, skip + sizeof(*esp));
  317                 if (m == NULL) {
  318                         DPRINTF(("%s: cannot pullup header\n", __func__));
  319                         ESPSTAT_INC(esps_hdrops);       /*XXX*/
  320                         error = ENOBUFS;
  321                         goto bad;
  322                 }
  323         }
  324         esp = (struct newesp *)(mtod(m, caddr_t) + skip);
  325 
  326         esph = sav->tdb_authalgxform;
  327         espx = sav->tdb_encalgxform;
  328 
  329         /* Determine the ESP header and auth length */
  330         if (sav->flags & SADB_X_EXT_OLD)
  331                 hlen = sizeof (struct esp) + sav->ivlen;
  332         else
  333                 hlen = sizeof (struct newesp) + sav->ivlen;
  334 
  335         alen = xform_ah_authsize(esph);
  336 
  337         /*
  338          * Verify payload length is multiple of encryption algorithm
  339          * block size.
  340          *
  341          * NB: This works for the null algorithm because the blocksize
  342          *     is 4 and all packets must be 4-byte aligned regardless
  343          *     of the algorithm.
  344          */
  345         plen = m->m_pkthdr.len - (skip + hlen + alen);
  346         if ((plen & (espx->blocksize - 1)) || (plen <= 0)) {
  347                 DPRINTF(("%s: payload of %d octets not a multiple of %d octets,"
  348                     "  SA %s/%08lx\n", __func__, plen, espx->blocksize,
  349                     ipsec_address(&sav->sah->saidx.dst, buf, sizeof(buf)),
  350                     (u_long)ntohl(sav->spi)));
  351                 ESPSTAT_INC(esps_badilen);
  352                 goto bad;
  353         }
  354 
  355         /*
  356          * Check sequence number.
  357          */
  358         SECASVAR_LOCK(sav);
  359         if (esph != NULL && sav->replay != NULL && sav->replay->wsize != 0) {
  360                 if (ipsec_chkreplay(ntohl(esp->esp_seq), sav) == 0) {
  361                         SECASVAR_UNLOCK(sav);
  362                         DPRINTF(("%s: packet replay check for %s\n", __func__,
  363                             ipsec_sa2str(sav, buf, sizeof(buf))));
  364                         ESPSTAT_INC(esps_replay);
  365                         error = EACCES;
  366                         goto bad;
  367                 }
  368         }
  369         cryptoid = sav->tdb_cryptoid;
  370         SECASVAR_UNLOCK(sav);
  371 
  372         /* Update the counters */
  373         ESPSTAT_ADD(esps_ibytes, m->m_pkthdr.len - (skip + hlen + alen));
  374 
  375         /* Get crypto descriptors */
  376         crp = crypto_getreq(esph && espx ? 2 : 1);
  377         if (crp == NULL) {
  378                 DPRINTF(("%s: failed to acquire crypto descriptors\n",
  379                         __func__));
  380                 ESPSTAT_INC(esps_crypto);
  381                 error = ENOBUFS;
  382                 goto bad;
  383         }
  384 
  385         /* Get IPsec-specific opaque pointer */
  386         xd = malloc(sizeof(*xd) + alen, M_XDATA, M_NOWAIT | M_ZERO);
  387         if (xd == NULL) {
  388                 DPRINTF(("%s: failed to allocate xform_data\n", __func__));
  389                 ESPSTAT_INC(esps_crypto);
  390                 crypto_freereq(crp);
  391                 error = ENOBUFS;
  392                 goto bad;
  393         }
  394 
  395         if (esph != NULL) {
  396                 struct cryptodesc *crda = crp->crp_desc;
  397 
  398                 IPSEC_ASSERT(crda != NULL, ("null ah crypto descriptor"));
  399 
  400                 /* Authentication descriptor */
  401                 crda->crd_skip = skip;
  402                 if (SAV_ISGCM(sav))
  403                         crda->crd_len = 8;      /* RFC4106 5, SPI + SN */
  404                 else
  405                         crda->crd_len = m->m_pkthdr.len - (skip + alen);
  406                 crda->crd_inject = m->m_pkthdr.len - alen;
  407 
  408                 crda->crd_alg = esph->type;
  409 
  410                 /* Copy the authenticator */
  411                 m_copydata(m, m->m_pkthdr.len - alen, alen,
  412                     (caddr_t) (xd + 1));
  413 
  414                 /* Chain authentication request */
  415                 crde = crda->crd_next;
  416         } else {
  417                 crde = crp->crp_desc;
  418         }
  419 
  420         /* Crypto operation descriptor */
  421         crp->crp_ilen = m->m_pkthdr.len; /* Total input length */
  422         crp->crp_flags = CRYPTO_F_IMBUF | CRYPTO_F_CBIFSYNC;
  423         if (V_async_crypto)
  424                 crp->crp_flags |= CRYPTO_F_ASYNC | CRYPTO_F_ASYNC_KEEPORDER;
  425         crp->crp_buf = (caddr_t) m;
  426         crp->crp_callback = esp_input_cb;
  427         crp->crp_session = cryptoid;
  428         crp->crp_opaque = (caddr_t) xd;
  429 
  430         /* These are passed as-is to the callback */
  431         xd->sav = sav;
  432         xd->protoff = protoff;
  433         xd->skip = skip;
  434         xd->cryptoid = cryptoid;
  435         xd->vnet = curvnet;
  436 
  437         /* Decryption descriptor */
  438         IPSEC_ASSERT(crde != NULL, ("null esp crypto descriptor"));
  439         crde->crd_skip = skip + hlen;
  440         crde->crd_len = m->m_pkthdr.len - (skip + hlen + alen);
  441         crde->crd_inject = skip + hlen - sav->ivlen;
  442 
  443         if (SAV_ISCTRORGCM(sav)) {
  444                 ivp = &crde->crd_iv[0];
  445 
  446                 /* GCM IV Format: RFC4106 4 */
  447                 /* CTR IV Format: RFC3686 4 */
  448                 /* Salt is last four bytes of key, RFC4106 8.1 */
  449                 /* Nonce is last four bytes of key, RFC3686 5.1 */
  450                 memcpy(ivp, sav->key_enc->key_data +
  451                     _KEYLEN(sav->key_enc) - 4, 4);
  452 
  453                 if (SAV_ISCTR(sav)) {
  454                         /* Initial block counter is 1, RFC3686 4 */
  455                         be32enc(&ivp[sav->ivlen + 4], 1);
  456                 }
  457 
  458                 m_copydata(m, skip + hlen - sav->ivlen, sav->ivlen, &ivp[4]);
  459                 crde->crd_flags |= CRD_F_IV_EXPLICIT;
  460         }
  461 
  462         crde->crd_alg = espx->type;
  463 
  464         return (crypto_dispatch(crp));
  465 bad:
  466         m_freem(m);
  467         key_freesav(&sav);
  468         return (error);
  469 }
  470 
  471 /*
  472  * ESP input callback from the crypto driver.
  473  */
  474 static int
  475 esp_input_cb(struct cryptop *crp)
  476 {
  477         IPSEC_DEBUG_DECLARE(char buf[128]);
  478         u_int8_t lastthree[3], aalg[AH_HMAC_MAXHASHLEN];
  479         const struct auth_hash *esph;
  480         struct mbuf *m;
  481         struct cryptodesc *crd;
  482         struct xform_data *xd;
  483         struct secasvar *sav;
  484         struct secasindex *saidx;
  485         caddr_t ptr;
  486         crypto_session_t cryptoid;
  487         int hlen, skip, protoff, error, alen;
  488 
  489         crd = crp->crp_desc;
  490         IPSEC_ASSERT(crd != NULL, ("null crypto descriptor!"));
  491 
  492         m = (struct mbuf *) crp->crp_buf;
  493         xd = (struct xform_data *) crp->crp_opaque;
  494         CURVNET_SET(xd->vnet);
  495         sav = xd->sav;
  496         skip = xd->skip;
  497         protoff = xd->protoff;
  498         cryptoid = xd->cryptoid;
  499         saidx = &sav->sah->saidx;
  500         esph = sav->tdb_authalgxform;
  501 
  502         /* Check for crypto errors */
  503         if (crp->crp_etype) {
  504                 if (crp->crp_etype == EAGAIN) {
  505                         /* Reset the session ID */
  506                         if (ipsec_updateid(sav, &crp->crp_session, &cryptoid) != 0)
  507                                 crypto_freesession(cryptoid);
  508                         xd->cryptoid = crp->crp_session;
  509                         CURVNET_RESTORE();
  510                         return (crypto_dispatch(crp));
  511                 }
  512                 ESPSTAT_INC(esps_noxform);
  513                 DPRINTF(("%s: crypto error %d\n", __func__, crp->crp_etype));
  514                 error = crp->crp_etype;
  515                 goto bad;
  516         }
  517 
  518         /* Shouldn't happen... */
  519         if (m == NULL) {
  520                 ESPSTAT_INC(esps_crypto);
  521                 DPRINTF(("%s: bogus returned buffer from crypto\n", __func__));
  522                 error = EINVAL;
  523                 goto bad;
  524         }
  525         ESPSTAT_INC(esps_hist[sav->alg_enc]);
  526 
  527         /* If authentication was performed, check now. */
  528         if (esph != NULL) {
  529                 alen = xform_ah_authsize(esph);
  530                 AHSTAT_INC(ahs_hist[sav->alg_auth]);
  531                 /* Copy the authenticator from the packet */
  532                 m_copydata(m, m->m_pkthdr.len - alen, alen, aalg);
  533                 ptr = (caddr_t) (xd + 1);
  534 
  535                 /* Verify authenticator */
  536                 if (timingsafe_bcmp(ptr, aalg, alen) != 0) {
  537                         DPRINTF(("%s: authentication hash mismatch for "
  538                             "packet in SA %s/%08lx\n", __func__,
  539                             ipsec_address(&saidx->dst, buf, sizeof(buf)),
  540                             (u_long) ntohl(sav->spi)));
  541                         ESPSTAT_INC(esps_badauth);
  542                         error = EACCES;
  543                         goto bad;
  544                 }
  545                 m->m_flags |= M_AUTHIPDGM;
  546                 /* Remove trailing authenticator */
  547                 m_adj(m, -alen);
  548         }
  549 
  550         /* Release the crypto descriptors */
  551         free(xd, M_XDATA), xd = NULL;
  552         crypto_freereq(crp), crp = NULL;
  553 
  554         /*
  555          * Packet is now decrypted.
  556          */
  557         m->m_flags |= M_DECRYPTED;
  558 
  559         /*
  560          * Update replay sequence number, if appropriate.
  561          */
  562         if (sav->replay) {
  563                 u_int32_t seq;
  564 
  565                 m_copydata(m, skip + offsetof(struct newesp, esp_seq),
  566                            sizeof (seq), (caddr_t) &seq);
  567                 SECASVAR_LOCK(sav);
  568                 if (ipsec_updatereplay(ntohl(seq), sav)) {
  569                         SECASVAR_UNLOCK(sav);
  570                         DPRINTF(("%s: packet replay check for %s\n", __func__,
  571                             ipsec_sa2str(sav, buf, sizeof(buf))));
  572                         ESPSTAT_INC(esps_replay);
  573                         error = EACCES;
  574                         goto bad;
  575                 }
  576                 SECASVAR_UNLOCK(sav);
  577         }
  578 
  579         /* Determine the ESP header length */
  580         if (sav->flags & SADB_X_EXT_OLD)
  581                 hlen = sizeof (struct esp) + sav->ivlen;
  582         else
  583                 hlen = sizeof (struct newesp) + sav->ivlen;
  584 
  585         /* Remove the ESP header and IV from the mbuf. */
  586         error = m_striphdr(m, skip, hlen);
  587         if (error) {
  588                 ESPSTAT_INC(esps_hdrops);
  589                 DPRINTF(("%s: bad mbuf chain, SA %s/%08lx\n", __func__,
  590                     ipsec_address(&sav->sah->saidx.dst, buf, sizeof(buf)),
  591                     (u_long) ntohl(sav->spi)));
  592                 goto bad;
  593         }
  594 
  595         /* Save the last three bytes of decrypted data */
  596         m_copydata(m, m->m_pkthdr.len - 3, 3, lastthree);
  597 
  598         /* Verify pad length */
  599         if (lastthree[1] + 2 > m->m_pkthdr.len - skip) {
  600                 ESPSTAT_INC(esps_badilen);
  601                 DPRINTF(("%s: invalid padding length %d for %u byte packet "
  602                     "in SA %s/%08lx\n", __func__, lastthree[1],
  603                     m->m_pkthdr.len - skip,
  604                     ipsec_address(&sav->sah->saidx.dst, buf, sizeof(buf)),
  605                     (u_long) ntohl(sav->spi)));
  606                 error = EINVAL;
  607                 goto bad;
  608         }
  609 
  610         /* Verify correct decryption by checking the last padding bytes */
  611         if ((sav->flags & SADB_X_EXT_PMASK) != SADB_X_EXT_PRAND) {
  612                 if (lastthree[1] != lastthree[0] && lastthree[1] != 0) {
  613                         ESPSTAT_INC(esps_badenc);
  614                         DPRINTF(("%s: decryption failed for packet in "
  615                             "SA %s/%08lx\n", __func__, ipsec_address(
  616                             &sav->sah->saidx.dst, buf, sizeof(buf)),
  617                             (u_long) ntohl(sav->spi)));
  618                         error = EINVAL;
  619                         goto bad;
  620                 }
  621         }
  622 
  623         /*
  624          * RFC4303 2.6:
  625          * Silently drop packet if next header field is IPPROTO_NONE.
  626          */
  627         if (lastthree[2] == IPPROTO_NONE)
  628                 goto bad;
  629 
  630         /* Trim the mbuf chain to remove trailing authenticator and padding */
  631         m_adj(m, -(lastthree[1] + 2));
  632 
  633         /* Restore the Next Protocol field */
  634         m_copyback(m, protoff, sizeof (u_int8_t), lastthree + 2);
  635 
  636         switch (saidx->dst.sa.sa_family) {
  637 #ifdef INET6
  638         case AF_INET6:
  639                 error = ipsec6_common_input_cb(m, sav, skip, protoff);
  640                 break;
  641 #endif
  642 #ifdef INET
  643         case AF_INET:
  644                 error = ipsec4_common_input_cb(m, sav, skip, protoff);
  645                 break;
  646 #endif
  647         default:
  648                 panic("%s: Unexpected address family: %d saidx=%p", __func__,
  649                     saidx->dst.sa.sa_family, saidx);
  650         }
  651         CURVNET_RESTORE();
  652         return error;
  653 bad:
  654         CURVNET_RESTORE();
  655         if (sav != NULL)
  656                 key_freesav(&sav);
  657         if (m != NULL)
  658                 m_freem(m);
  659         if (xd != NULL)
  660                 free(xd, M_XDATA);
  661         if (crp != NULL)
  662                 crypto_freereq(crp);
  663         return error;
  664 }
  665 /*
  666  * ESP output routine, called by ipsec[46]_perform_request().
  667  */
  668 static int
  669 esp_output(struct mbuf *m, struct secpolicy *sp, struct secasvar *sav,
  670     u_int idx, int skip, int protoff)
  671 {
  672         IPSEC_DEBUG_DECLARE(char buf[IPSEC_ADDRSTRLEN]);
  673         struct cryptodesc *crde = NULL, *crda = NULL;
  674         struct cryptop *crp;
  675         const struct auth_hash *esph;
  676         const struct enc_xform *espx;
  677         struct mbuf *mo = NULL;
  678         struct xform_data *xd;
  679         struct secasindex *saidx;
  680         unsigned char *pad;
  681         uint8_t *ivp;
  682         uint64_t cntr;
  683         crypto_session_t cryptoid;
  684         int hlen, rlen, padding, blks, alen, i, roff;
  685         int error, maxpacketsize;
  686         uint8_t prot;
  687 
  688         IPSEC_ASSERT(sav != NULL, ("null SA"));
  689         esph = sav->tdb_authalgxform;
  690         espx = sav->tdb_encalgxform;
  691         IPSEC_ASSERT(espx != NULL, ("null encoding xform"));
  692 
  693         if (sav->flags & SADB_X_EXT_OLD)
  694                 hlen = sizeof (struct esp) + sav->ivlen;
  695         else
  696                 hlen = sizeof (struct newesp) + sav->ivlen;
  697 
  698         rlen = m->m_pkthdr.len - skip;  /* Raw payload length. */
  699         /*
  700          * RFC4303 2.4 Requires 4 byte alignment.
  701          */
  702         blks = MAX(4, espx->blocksize);         /* Cipher blocksize */
  703 
  704         /* XXX clamp padding length a la KAME??? */
  705         padding = ((blks - ((rlen + 2) % blks)) % blks) + 2;
  706 
  707         alen = xform_ah_authsize(esph);
  708 
  709         ESPSTAT_INC(esps_output);
  710 
  711         saidx = &sav->sah->saidx;
  712         /* Check for maximum packet size violations. */
  713         switch (saidx->dst.sa.sa_family) {
  714 #ifdef INET
  715         case AF_INET:
  716                 maxpacketsize = IP_MAXPACKET;
  717                 break;
  718 #endif /* INET */
  719 #ifdef INET6
  720         case AF_INET6:
  721                 maxpacketsize = IPV6_MAXPACKET;
  722                 break;
  723 #endif /* INET6 */
  724         default:
  725                 DPRINTF(("%s: unknown/unsupported protocol "
  726                     "family %d, SA %s/%08lx\n", __func__,
  727                     saidx->dst.sa.sa_family, ipsec_address(&saidx->dst,
  728                         buf, sizeof(buf)), (u_long) ntohl(sav->spi)));
  729                 ESPSTAT_INC(esps_nopf);
  730                 error = EPFNOSUPPORT;
  731                 goto bad;
  732         }
  733         /*
  734         DPRINTF(("%s: skip %d hlen %d rlen %d padding %d alen %d blksd %d\n",
  735                 __func__, skip, hlen, rlen, padding, alen, blks)); */
  736         if (skip + hlen + rlen + padding + alen > maxpacketsize) {
  737                 DPRINTF(("%s: packet in SA %s/%08lx got too big "
  738                     "(len %u, max len %u)\n", __func__,
  739                     ipsec_address(&saidx->dst, buf, sizeof(buf)),
  740                     (u_long) ntohl(sav->spi),
  741                     skip + hlen + rlen + padding + alen, maxpacketsize));
  742                 ESPSTAT_INC(esps_toobig);
  743                 error = EMSGSIZE;
  744                 goto bad;
  745         }
  746 
  747         /* Update the counters. */
  748         ESPSTAT_ADD(esps_obytes, m->m_pkthdr.len - skip);
  749 
  750         m = m_unshare(m, M_NOWAIT);
  751         if (m == NULL) {
  752                 DPRINTF(("%s: cannot clone mbuf chain, SA %s/%08lx\n", __func__,
  753                     ipsec_address(&saidx->dst, buf, sizeof(buf)),
  754                     (u_long) ntohl(sav->spi)));
  755                 ESPSTAT_INC(esps_hdrops);
  756                 error = ENOBUFS;
  757                 goto bad;
  758         }
  759 
  760         /* Inject ESP header. */
  761         mo = m_makespace(m, skip, hlen, &roff);
  762         if (mo == NULL) {
  763                 DPRINTF(("%s: %u byte ESP hdr inject failed for SA %s/%08lx\n",
  764                     __func__, hlen, ipsec_address(&saidx->dst, buf,
  765                     sizeof(buf)), (u_long) ntohl(sav->spi)));
  766                 ESPSTAT_INC(esps_hdrops);       /* XXX diffs from openbsd */
  767                 error = ENOBUFS;
  768                 goto bad;
  769         }
  770 
  771         /* Initialize ESP header. */
  772         bcopy((caddr_t) &sav->spi, mtod(mo, caddr_t) + roff,
  773             sizeof(uint32_t));
  774         SECASVAR_LOCK(sav);
  775         if (sav->replay) {
  776                 uint32_t replay;
  777 
  778 #ifdef REGRESSION
  779                 /* Emulate replay attack when ipsec_replay is TRUE. */
  780                 if (!V_ipsec_replay)
  781 #endif
  782                         sav->replay->count++;
  783                 replay = htonl(sav->replay->count);
  784 
  785                 bcopy((caddr_t) &replay, mtod(mo, caddr_t) + roff +
  786                     sizeof(uint32_t), sizeof(uint32_t));
  787         }
  788         cryptoid = sav->tdb_cryptoid;
  789         if (SAV_ISCTRORGCM(sav))
  790                 cntr = sav->cntr++;
  791         SECASVAR_UNLOCK(sav);
  792 
  793         /*
  794          * Add padding -- better to do it ourselves than use the crypto engine,
  795          * although if/when we support compression, we'd have to do that.
  796          */
  797         pad = (u_char *) m_pad(m, padding + alen);
  798         if (pad == NULL) {
  799                 DPRINTF(("%s: m_pad failed for SA %s/%08lx\n", __func__,
  800                     ipsec_address(&saidx->dst, buf, sizeof(buf)),
  801                     (u_long) ntohl(sav->spi)));
  802                 m = NULL;               /* NB: free'd by m_pad */
  803                 error = ENOBUFS;
  804                 goto bad;
  805         }
  806 
  807         /*
  808          * Add padding: random, zero, or self-describing.
  809          * XXX catch unexpected setting
  810          */
  811         switch (sav->flags & SADB_X_EXT_PMASK) {
  812         case SADB_X_EXT_PRAND:
  813                 (void) read_random(pad, padding - 2);
  814                 break;
  815         case SADB_X_EXT_PZERO:
  816                 bzero(pad, padding - 2);
  817                 break;
  818         case SADB_X_EXT_PSEQ:
  819                 for (i = 0; i < padding - 2; i++)
  820                         pad[i] = i+1;
  821                 break;
  822         }
  823 
  824         /* Fix padding length and Next Protocol in padding itself. */
  825         pad[padding - 2] = padding - 2;
  826         m_copydata(m, protoff, sizeof(u_int8_t), pad + padding - 1);
  827 
  828         /* Fix Next Protocol in IPv4/IPv6 header. */
  829         prot = IPPROTO_ESP;
  830         m_copyback(m, protoff, sizeof(u_int8_t), (u_char *) &prot);
  831 
  832         /* Get crypto descriptors. */
  833         crp = crypto_getreq(esph != NULL ? 2 : 1);
  834         if (crp == NULL) {
  835                 DPRINTF(("%s: failed to acquire crypto descriptors\n",
  836                         __func__));
  837                 ESPSTAT_INC(esps_crypto);
  838                 error = ENOBUFS;
  839                 goto bad;
  840         }
  841 
  842         /* IPsec-specific opaque crypto info. */
  843         xd =  malloc(sizeof(struct xform_data), M_XDATA, M_NOWAIT | M_ZERO);
  844         if (xd == NULL) {
  845                 crypto_freereq(crp);
  846                 DPRINTF(("%s: failed to allocate xform_data\n", __func__));
  847                 ESPSTAT_INC(esps_crypto);
  848                 error = ENOBUFS;
  849                 goto bad;
  850         }
  851 
  852         crde = crp->crp_desc;
  853         crda = crde->crd_next;
  854 
  855         /* Encryption descriptor. */
  856         crde->crd_skip = skip + hlen;
  857         crde->crd_len = m->m_pkthdr.len - (skip + hlen + alen);
  858         crde->crd_flags = CRD_F_ENCRYPT;
  859         crde->crd_inject = skip + hlen - sav->ivlen;
  860 
  861         /* Encryption operation. */
  862         crde->crd_alg = espx->type;
  863         if (SAV_ISCTRORGCM(sav)) {
  864                 ivp = &crde->crd_iv[0];
  865 
  866                 /* GCM IV Format: RFC4106 4 */
  867                 /* CTR IV Format: RFC3686 4 */
  868                 /* Salt is last four bytes of key, RFC4106 8.1 */
  869                 /* Nonce is last four bytes of key, RFC3686 5.1 */
  870                 memcpy(ivp, sav->key_enc->key_data +
  871                     _KEYLEN(sav->key_enc) - 4, 4);
  872                 be64enc(&ivp[4], cntr);
  873                 if (SAV_ISCTR(sav)) {
  874                         /* Initial block counter is 1, RFC3686 4 */
  875                         /* XXXAE: should we use this only for first packet? */
  876                         be32enc(&ivp[sav->ivlen + 4], 1);
  877                 }
  878 
  879                 m_copyback(m, skip + hlen - sav->ivlen, sav->ivlen, &ivp[4]);
  880                 crde->crd_flags |= CRD_F_IV_EXPLICIT|CRD_F_IV_PRESENT;
  881         }
  882 
  883         /* Callback parameters */
  884         xd->sp = sp;
  885         xd->sav = sav;
  886         xd->idx = idx;
  887         xd->cryptoid = cryptoid;
  888         xd->vnet = curvnet;
  889 
  890         /* Crypto operation descriptor. */
  891         crp->crp_ilen = m->m_pkthdr.len; /* Total input length. */
  892         crp->crp_flags = CRYPTO_F_IMBUF | CRYPTO_F_CBIFSYNC;
  893         if (V_async_crypto)
  894                 crp->crp_flags |= CRYPTO_F_ASYNC | CRYPTO_F_ASYNC_KEEPORDER;
  895         crp->crp_buf = (caddr_t) m;
  896         crp->crp_callback = esp_output_cb;
  897         crp->crp_opaque = (caddr_t) xd;
  898         crp->crp_session = cryptoid;
  899 
  900         if (esph) {
  901                 /* Authentication descriptor. */
  902                 crda->crd_alg = esph->type;
  903                 crda->crd_skip = skip;
  904                 if (SAV_ISGCM(sav))
  905                         crda->crd_len = 8;      /* RFC4106 5, SPI + SN */
  906                 else
  907                         crda->crd_len = m->m_pkthdr.len - (skip + alen);
  908                 crda->crd_inject = m->m_pkthdr.len - alen;
  909         }
  910 
  911         return crypto_dispatch(crp);
  912 bad:
  913         if (m)
  914                 m_freem(m);
  915         key_freesav(&sav);
  916         key_freesp(&sp);
  917         return (error);
  918 }
  919 /*
  920  * ESP output callback from the crypto driver.
  921  */
  922 static int
  923 esp_output_cb(struct cryptop *crp)
  924 {
  925         struct xform_data *xd;
  926         struct secpolicy *sp;
  927         struct secasvar *sav;
  928         struct mbuf *m;
  929         crypto_session_t cryptoid;
  930         u_int idx;
  931         int error;
  932 
  933         xd = (struct xform_data *) crp->crp_opaque;
  934         CURVNET_SET(xd->vnet);
  935         m = (struct mbuf *) crp->crp_buf;
  936         sp = xd->sp;
  937         sav = xd->sav;
  938         idx = xd->idx;
  939         cryptoid = xd->cryptoid;
  940 
  941         /* Check for crypto errors. */
  942         if (crp->crp_etype) {
  943                 if (crp->crp_etype == EAGAIN) {
  944                         /* Reset the session ID */
  945                         if (ipsec_updateid(sav, &crp->crp_session, &cryptoid) != 0)
  946                                 crypto_freesession(cryptoid);
  947                         xd->cryptoid = crp->crp_session;
  948                         CURVNET_RESTORE();
  949                         return (crypto_dispatch(crp));
  950                 }
  951                 ESPSTAT_INC(esps_noxform);
  952                 DPRINTF(("%s: crypto error %d\n", __func__, crp->crp_etype));
  953                 error = crp->crp_etype;
  954                 m_freem(m);
  955                 goto bad;
  956         }
  957 
  958         /* Shouldn't happen... */
  959         if (m == NULL) {
  960                 ESPSTAT_INC(esps_crypto);
  961                 DPRINTF(("%s: bogus returned buffer from crypto\n", __func__));
  962                 error = EINVAL;
  963                 goto bad;
  964         }
  965         free(xd, M_XDATA);
  966         crypto_freereq(crp);
  967         ESPSTAT_INC(esps_hist[sav->alg_enc]);
  968         if (sav->tdb_authalgxform != NULL)
  969                 AHSTAT_INC(ahs_hist[sav->alg_auth]);
  970 
  971 #ifdef REGRESSION
  972         /* Emulate man-in-the-middle attack when ipsec_integrity is TRUE. */
  973         if (V_ipsec_integrity) {
  974                 static unsigned char ipseczeroes[AH_HMAC_MAXHASHLEN];
  975                 const struct auth_hash *esph;
  976 
  977                 /*
  978                  * Corrupt HMAC if we want to test integrity verification of
  979                  * the other side.
  980                  */
  981                 esph = sav->tdb_authalgxform;
  982                 if (esph !=  NULL) {
  983                         int alen;
  984 
  985                         alen = xform_ah_authsize(esph);
  986                         m_copyback(m, m->m_pkthdr.len - alen,
  987                             alen, ipseczeroes);
  988                 }
  989         }
  990 #endif
  991 
  992         /* NB: m is reclaimed by ipsec_process_done. */
  993         error = ipsec_process_done(m, sp, sav, idx);
  994         CURVNET_RESTORE();
  995         return (error);
  996 bad:
  997         CURVNET_RESTORE();
  998         free(xd, M_XDATA);
  999         crypto_freereq(crp);
 1000         key_freesav(&sav);
 1001         key_freesp(&sp);
 1002         return (error);
 1003 }
 1004 
 1005 static struct xformsw esp_xformsw = {
 1006         .xf_type =      XF_ESP,
 1007         .xf_name =      "IPsec ESP",
 1008         .xf_init =      esp_init,
 1009         .xf_zeroize =   esp_zeroize,
 1010         .xf_input =     esp_input,
 1011         .xf_output =    esp_output,
 1012 };
 1013 
 1014 SYSINIT(esp_xform_init, SI_SUB_PROTO_DOMAIN, SI_ORDER_MIDDLE,
 1015     xform_attach, &esp_xformsw);
 1016 SYSUNINIT(esp_xform_uninit, SI_SUB_PROTO_DOMAIN, SI_ORDER_MIDDLE,
 1017     xform_detach, &esp_xformsw);

Cache object: ec4198c2d82b6354bc7e956ac1b88444


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