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/11/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         uint64_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         /* XXX don't pullup, just copy header */
  316         IP6_EXTHDR_GET(esp, struct newesp *, m, skip, sizeof (struct newesp));
  317 
  318         esph = sav->tdb_authalgxform;
  319         espx = sav->tdb_encalgxform;
  320 
  321         /* Determine the ESP header and auth length */
  322         if (sav->flags & SADB_X_EXT_OLD)
  323                 hlen = sizeof (struct esp) + sav->ivlen;
  324         else
  325                 hlen = sizeof (struct newesp) + sav->ivlen;
  326 
  327         alen = xform_ah_authsize(esph);
  328 
  329         /*
  330          * Verify payload length is multiple of encryption algorithm
  331          * block size.
  332          *
  333          * NB: This works for the null algorithm because the blocksize
  334          *     is 4 and all packets must be 4-byte aligned regardless
  335          *     of the algorithm.
  336          */
  337         plen = m->m_pkthdr.len - (skip + hlen + alen);
  338         if ((plen & (espx->blocksize - 1)) || (plen <= 0)) {
  339                 DPRINTF(("%s: payload of %d octets not a multiple of %d octets,"
  340                     "  SA %s/%08lx\n", __func__, plen, espx->blocksize,
  341                     ipsec_address(&sav->sah->saidx.dst, buf, sizeof(buf)),
  342                     (u_long)ntohl(sav->spi)));
  343                 ESPSTAT_INC(esps_badilen);
  344                 goto bad;
  345         }
  346 
  347         /*
  348          * Check sequence number.
  349          */
  350         SECASVAR_LOCK(sav);
  351         if (esph != NULL && sav->replay != NULL && sav->replay->wsize != 0) {
  352                 if (ipsec_chkreplay(ntohl(esp->esp_seq), sav) == 0) {
  353                         SECASVAR_UNLOCK(sav);
  354                         DPRINTF(("%s: packet replay check for %s\n", __func__,
  355                             ipsec_sa2str(sav, buf, sizeof(buf))));
  356                         ESPSTAT_INC(esps_replay);
  357                         error = EACCES;
  358                         goto bad;
  359                 }
  360         }
  361         cryptoid = sav->tdb_cryptoid;
  362         SECASVAR_UNLOCK(sav);
  363 
  364         /* Update the counters */
  365         ESPSTAT_ADD(esps_ibytes, m->m_pkthdr.len - (skip + hlen + alen));
  366 
  367         /* Get crypto descriptors */
  368         crp = crypto_getreq(esph && espx ? 2 : 1);
  369         if (crp == NULL) {
  370                 DPRINTF(("%s: failed to acquire crypto descriptors\n",
  371                         __func__));
  372                 ESPSTAT_INC(esps_crypto);
  373                 error = ENOBUFS;
  374                 goto bad;
  375         }
  376 
  377         /* Get IPsec-specific opaque pointer */
  378         xd = malloc(sizeof(*xd) + alen, M_XDATA, M_NOWAIT | M_ZERO);
  379         if (xd == NULL) {
  380                 DPRINTF(("%s: failed to allocate xform_data\n", __func__));
  381                 ESPSTAT_INC(esps_crypto);
  382                 crypto_freereq(crp);
  383                 error = ENOBUFS;
  384                 goto bad;
  385         }
  386 
  387         if (esph != NULL) {
  388                 struct cryptodesc *crda = crp->crp_desc;
  389 
  390                 IPSEC_ASSERT(crda != NULL, ("null ah crypto descriptor"));
  391 
  392                 /* Authentication descriptor */
  393                 crda->crd_skip = skip;
  394                 if (SAV_ISGCM(sav))
  395                         crda->crd_len = 8;      /* RFC4106 5, SPI + SN */
  396                 else
  397                         crda->crd_len = m->m_pkthdr.len - (skip + alen);
  398                 crda->crd_inject = m->m_pkthdr.len - alen;
  399 
  400                 crda->crd_alg = esph->type;
  401 
  402                 /* Copy the authenticator */
  403                 m_copydata(m, m->m_pkthdr.len - alen, alen,
  404                     (caddr_t) (xd + 1));
  405 
  406                 /* Chain authentication request */
  407                 crde = crda->crd_next;
  408         } else {
  409                 crde = crp->crp_desc;
  410         }
  411 
  412         /* Crypto operation descriptor */
  413         crp->crp_ilen = m->m_pkthdr.len; /* Total input length */
  414         crp->crp_flags = CRYPTO_F_IMBUF | CRYPTO_F_CBIFSYNC;
  415         crp->crp_buf = (caddr_t) m;
  416         crp->crp_callback = esp_input_cb;
  417         crp->crp_sid = cryptoid;
  418         crp->crp_opaque = (caddr_t) xd;
  419 
  420         /* These are passed as-is to the callback */
  421         xd->sav = sav;
  422         xd->protoff = protoff;
  423         xd->skip = skip;
  424         xd->cryptoid = cryptoid;
  425         xd->vnet = curvnet;
  426 
  427         /* Decryption descriptor */
  428         IPSEC_ASSERT(crde != NULL, ("null esp crypto descriptor"));
  429         crde->crd_skip = skip + hlen;
  430         crde->crd_len = m->m_pkthdr.len - (skip + hlen + alen);
  431         crde->crd_inject = skip + hlen - sav->ivlen;
  432 
  433         if (SAV_ISCTRORGCM(sav)) {
  434                 ivp = &crde->crd_iv[0];
  435 
  436                 /* GCM IV Format: RFC4106 4 */
  437                 /* CTR IV Format: RFC3686 4 */
  438                 /* Salt is last four bytes of key, RFC4106 8.1 */
  439                 /* Nonce is last four bytes of key, RFC3686 5.1 */
  440                 memcpy(ivp, sav->key_enc->key_data +
  441                     _KEYLEN(sav->key_enc) - 4, 4);
  442 
  443                 if (SAV_ISCTR(sav)) {
  444                         /* Initial block counter is 1, RFC3686 4 */
  445                         be32enc(&ivp[sav->ivlen + 4], 1);
  446                 }
  447 
  448                 m_copydata(m, skip + hlen - sav->ivlen, sav->ivlen, &ivp[4]);
  449                 crde->crd_flags |= CRD_F_IV_EXPLICIT;
  450         }
  451 
  452         crde->crd_alg = espx->type;
  453 
  454         return (crypto_dispatch(crp));
  455 bad:
  456         m_freem(m);
  457         key_freesav(&sav);
  458         return (error);
  459 }
  460 
  461 /*
  462  * ESP input callback from the crypto driver.
  463  */
  464 static int
  465 esp_input_cb(struct cryptop *crp)
  466 {
  467         IPSEC_DEBUG_DECLARE(char buf[128]);
  468         u_int8_t lastthree[3], aalg[AH_HMAC_MAXHASHLEN];
  469         const struct auth_hash *esph;
  470         const struct enc_xform *espx;
  471         struct mbuf *m;
  472         struct cryptodesc *crd;
  473         struct xform_data *xd;
  474         struct secasvar *sav;
  475         struct secasindex *saidx;
  476         caddr_t ptr;
  477         uint64_t cryptoid;
  478         int hlen, skip, protoff, error, alen;
  479 
  480         crd = crp->crp_desc;
  481         IPSEC_ASSERT(crd != NULL, ("null crypto descriptor!"));
  482 
  483         m = (struct mbuf *) crp->crp_buf;
  484         xd = (struct xform_data *) crp->crp_opaque;
  485         CURVNET_SET(xd->vnet);
  486         sav = xd->sav;
  487         skip = xd->skip;
  488         protoff = xd->protoff;
  489         cryptoid = xd->cryptoid;
  490         saidx = &sav->sah->saidx;
  491         esph = sav->tdb_authalgxform;
  492         espx = sav->tdb_encalgxform;
  493 
  494         /* Check for crypto errors */
  495         if (crp->crp_etype) {
  496                 if (crp->crp_etype == EAGAIN) {
  497                         /* Reset the session ID */
  498                         if (ipsec_updateid(sav, &crp->crp_sid, &cryptoid) != 0)
  499                                 crypto_freesession(cryptoid);
  500                         xd->cryptoid = crp->crp_sid;
  501                         CURVNET_RESTORE();
  502                         return (crypto_dispatch(crp));
  503                 }
  504                 ESPSTAT_INC(esps_noxform);
  505                 DPRINTF(("%s: crypto error %d\n", __func__, crp->crp_etype));
  506                 error = crp->crp_etype;
  507                 goto bad;
  508         }
  509 
  510         /* Shouldn't happen... */
  511         if (m == NULL) {
  512                 ESPSTAT_INC(esps_crypto);
  513                 DPRINTF(("%s: bogus returned buffer from crypto\n", __func__));
  514                 error = EINVAL;
  515                 goto bad;
  516         }
  517         ESPSTAT_INC(esps_hist[sav->alg_enc]);
  518 
  519         /* If authentication was performed, check now. */
  520         if (esph != NULL) {
  521                 alen = xform_ah_authsize(esph);
  522                 AHSTAT_INC(ahs_hist[sav->alg_auth]);
  523                 /* Copy the authenticator from the packet */
  524                 m_copydata(m, m->m_pkthdr.len - alen, alen, aalg);
  525                 ptr = (caddr_t) (xd + 1);
  526 
  527                 /* Verify authenticator */
  528                 if (timingsafe_bcmp(ptr, aalg, alen) != 0) {
  529                         DPRINTF(("%s: authentication hash mismatch for "
  530                             "packet in SA %s/%08lx\n", __func__,
  531                             ipsec_address(&saidx->dst, buf, sizeof(buf)),
  532                             (u_long) ntohl(sav->spi)));
  533                         ESPSTAT_INC(esps_badauth);
  534                         error = EACCES;
  535                         goto bad;
  536                 }
  537                 m->m_flags |= M_AUTHIPDGM;
  538                 /* Remove trailing authenticator */
  539                 m_adj(m, -alen);
  540         }
  541 
  542         /* Release the crypto descriptors */
  543         free(xd, M_XDATA), xd = NULL;
  544         crypto_freereq(crp), crp = NULL;
  545 
  546         /*
  547          * Packet is now decrypted.
  548          */
  549         m->m_flags |= M_DECRYPTED;
  550 
  551         /*
  552          * Update replay sequence number, if appropriate.
  553          */
  554         if (sav->replay) {
  555                 u_int32_t seq;
  556 
  557                 m_copydata(m, skip + offsetof(struct newesp, esp_seq),
  558                            sizeof (seq), (caddr_t) &seq);
  559                 SECASVAR_LOCK(sav);
  560                 if (ipsec_updatereplay(ntohl(seq), sav)) {
  561                         SECASVAR_UNLOCK(sav);
  562                         DPRINTF(("%s: packet replay check for %s\n", __func__,
  563                             ipsec_sa2str(sav, buf, sizeof(buf))));
  564                         ESPSTAT_INC(esps_replay);
  565                         error = EACCES;
  566                         goto bad;
  567                 }
  568                 SECASVAR_UNLOCK(sav);
  569         }
  570 
  571         /* Determine the ESP header length */
  572         if (sav->flags & SADB_X_EXT_OLD)
  573                 hlen = sizeof (struct esp) + sav->ivlen;
  574         else
  575                 hlen = sizeof (struct newesp) + sav->ivlen;
  576 
  577         /* Remove the ESP header and IV from the mbuf. */
  578         error = m_striphdr(m, skip, hlen);
  579         if (error) {
  580                 ESPSTAT_INC(esps_hdrops);
  581                 DPRINTF(("%s: bad mbuf chain, SA %s/%08lx\n", __func__,
  582                     ipsec_address(&sav->sah->saidx.dst, buf, sizeof(buf)),
  583                     (u_long) ntohl(sav->spi)));
  584                 goto bad;
  585         }
  586 
  587         /* Save the last three bytes of decrypted data */
  588         m_copydata(m, m->m_pkthdr.len - 3, 3, lastthree);
  589 
  590         /* Verify pad length */
  591         if (lastthree[1] + 2 > m->m_pkthdr.len - skip) {
  592                 ESPSTAT_INC(esps_badilen);
  593                 DPRINTF(("%s: invalid padding length %d for %u byte packet "
  594                     "in SA %s/%08lx\n", __func__, lastthree[1],
  595                     m->m_pkthdr.len - skip,
  596                     ipsec_address(&sav->sah->saidx.dst, buf, sizeof(buf)),
  597                     (u_long) ntohl(sav->spi)));
  598                 error = EINVAL;
  599                 goto bad;
  600         }
  601 
  602         /* Verify correct decryption by checking the last padding bytes */
  603         if ((sav->flags & SADB_X_EXT_PMASK) != SADB_X_EXT_PRAND) {
  604                 if (lastthree[1] != lastthree[0] && lastthree[1] != 0) {
  605                         ESPSTAT_INC(esps_badenc);
  606                         DPRINTF(("%s: decryption failed for packet in "
  607                             "SA %s/%08lx\n", __func__, ipsec_address(
  608                             &sav->sah->saidx.dst, buf, sizeof(buf)),
  609                             (u_long) ntohl(sav->spi)));
  610                         error = EINVAL;
  611                         goto bad;
  612                 }
  613         }
  614 
  615         /*
  616          * RFC4303 2.6:
  617          * Silently drop packet if next header field is IPPROTO_NONE.
  618          */
  619         if (lastthree[2] == IPPROTO_NONE)
  620                 goto bad;
  621 
  622         /* Trim the mbuf chain to remove trailing authenticator and padding */
  623         m_adj(m, -(lastthree[1] + 2));
  624 
  625         /* Restore the Next Protocol field */
  626         m_copyback(m, protoff, sizeof (u_int8_t), lastthree + 2);
  627 
  628         switch (saidx->dst.sa.sa_family) {
  629 #ifdef INET6
  630         case AF_INET6:
  631                 error = ipsec6_common_input_cb(m, sav, skip, protoff);
  632                 break;
  633 #endif
  634 #ifdef INET
  635         case AF_INET:
  636                 error = ipsec4_common_input_cb(m, sav, skip, protoff);
  637                 break;
  638 #endif
  639         default:
  640                 panic("%s: Unexpected address family: %d saidx=%p", __func__,
  641                     saidx->dst.sa.sa_family, saidx);
  642         }
  643         CURVNET_RESTORE();
  644         return error;
  645 bad:
  646         CURVNET_RESTORE();
  647         if (sav != NULL)
  648                 key_freesav(&sav);
  649         if (m != NULL)
  650                 m_freem(m);
  651         if (xd != NULL)
  652                 free(xd, M_XDATA);
  653         if (crp != NULL)
  654                 crypto_freereq(crp);
  655         return error;
  656 }
  657 /*
  658  * ESP output routine, called by ipsec[46]_perform_request().
  659  */
  660 static int
  661 esp_output(struct mbuf *m, struct secpolicy *sp, struct secasvar *sav,
  662     u_int idx, int skip, int protoff)
  663 {
  664         IPSEC_DEBUG_DECLARE(char buf[IPSEC_ADDRSTRLEN]);
  665         struct cryptodesc *crde = NULL, *crda = NULL;
  666         struct cryptop *crp;
  667         const struct auth_hash *esph;
  668         const struct enc_xform *espx;
  669         struct mbuf *mo = NULL;
  670         struct xform_data *xd;
  671         struct secasindex *saidx;
  672         unsigned char *pad;
  673         uint8_t *ivp;
  674         uint64_t cntr, cryptoid;
  675         int hlen, rlen, padding, blks, alen, i, roff;
  676         int error, maxpacketsize;
  677         uint8_t prot;
  678 
  679         IPSEC_ASSERT(sav != NULL, ("null SA"));
  680         esph = sav->tdb_authalgxform;
  681         espx = sav->tdb_encalgxform;
  682         IPSEC_ASSERT(espx != NULL, ("null encoding xform"));
  683 
  684         if (sav->flags & SADB_X_EXT_OLD)
  685                 hlen = sizeof (struct esp) + sav->ivlen;
  686         else
  687                 hlen = sizeof (struct newesp) + sav->ivlen;
  688 
  689         rlen = m->m_pkthdr.len - skip;  /* Raw payload length. */
  690         /*
  691          * RFC4303 2.4 Requires 4 byte alignment.
  692          */
  693         blks = MAX(4, espx->blocksize);         /* Cipher blocksize */
  694 
  695         /* XXX clamp padding length a la KAME??? */
  696         padding = ((blks - ((rlen + 2) % blks)) % blks) + 2;
  697 
  698         alen = xform_ah_authsize(esph);
  699 
  700         ESPSTAT_INC(esps_output);
  701 
  702         saidx = &sav->sah->saidx;
  703         /* Check for maximum packet size violations. */
  704         switch (saidx->dst.sa.sa_family) {
  705 #ifdef INET
  706         case AF_INET:
  707                 maxpacketsize = IP_MAXPACKET;
  708                 break;
  709 #endif /* INET */
  710 #ifdef INET6
  711         case AF_INET6:
  712                 maxpacketsize = IPV6_MAXPACKET;
  713                 break;
  714 #endif /* INET6 */
  715         default:
  716                 DPRINTF(("%s: unknown/unsupported protocol "
  717                     "family %d, SA %s/%08lx\n", __func__,
  718                     saidx->dst.sa.sa_family, ipsec_address(&saidx->dst,
  719                         buf, sizeof(buf)), (u_long) ntohl(sav->spi)));
  720                 ESPSTAT_INC(esps_nopf);
  721                 error = EPFNOSUPPORT;
  722                 goto bad;
  723         }
  724         /*
  725         DPRINTF(("%s: skip %d hlen %d rlen %d padding %d alen %d blksd %d\n",
  726                 __func__, skip, hlen, rlen, padding, alen, blks)); */
  727         if (skip + hlen + rlen + padding + alen > maxpacketsize) {
  728                 DPRINTF(("%s: packet in SA %s/%08lx got too big "
  729                     "(len %u, max len %u)\n", __func__,
  730                     ipsec_address(&saidx->dst, buf, sizeof(buf)),
  731                     (u_long) ntohl(sav->spi),
  732                     skip + hlen + rlen + padding + alen, maxpacketsize));
  733                 ESPSTAT_INC(esps_toobig);
  734                 error = EMSGSIZE;
  735                 goto bad;
  736         }
  737 
  738         /* Update the counters. */
  739         ESPSTAT_ADD(esps_obytes, m->m_pkthdr.len - skip);
  740 
  741         m = m_unshare(m, M_NOWAIT);
  742         if (m == NULL) {
  743                 DPRINTF(("%s: cannot clone mbuf chain, SA %s/%08lx\n", __func__,
  744                     ipsec_address(&saidx->dst, buf, sizeof(buf)),
  745                     (u_long) ntohl(sav->spi)));
  746                 ESPSTAT_INC(esps_hdrops);
  747                 error = ENOBUFS;
  748                 goto bad;
  749         }
  750 
  751         /* Inject ESP header. */
  752         mo = m_makespace(m, skip, hlen, &roff);
  753         if (mo == NULL) {
  754                 DPRINTF(("%s: %u byte ESP hdr inject failed for SA %s/%08lx\n",
  755                     __func__, hlen, ipsec_address(&saidx->dst, buf,
  756                     sizeof(buf)), (u_long) ntohl(sav->spi)));
  757                 ESPSTAT_INC(esps_hdrops);       /* XXX diffs from openbsd */
  758                 error = ENOBUFS;
  759                 goto bad;
  760         }
  761 
  762         /* Initialize ESP header. */
  763         bcopy((caddr_t) &sav->spi, mtod(mo, caddr_t) + roff,
  764             sizeof(uint32_t));
  765         SECASVAR_LOCK(sav);
  766         if (sav->replay) {
  767                 uint32_t replay;
  768 
  769 #ifdef REGRESSION
  770                 /* Emulate replay attack when ipsec_replay is TRUE. */
  771                 if (!V_ipsec_replay)
  772 #endif
  773                         sav->replay->count++;
  774                 replay = htonl(sav->replay->count);
  775 
  776                 bcopy((caddr_t) &replay, mtod(mo, caddr_t) + roff +
  777                     sizeof(uint32_t), sizeof(uint32_t));
  778         }
  779         cryptoid = sav->tdb_cryptoid;
  780         if (SAV_ISCTRORGCM(sav))
  781                 cntr = sav->cntr++;
  782         SECASVAR_UNLOCK(sav);
  783 
  784         /*
  785          * Add padding -- better to do it ourselves than use the crypto engine,
  786          * although if/when we support compression, we'd have to do that.
  787          */
  788         pad = (u_char *) m_pad(m, padding + alen);
  789         if (pad == NULL) {
  790                 DPRINTF(("%s: m_pad failed for SA %s/%08lx\n", __func__,
  791                     ipsec_address(&saidx->dst, buf, sizeof(buf)),
  792                     (u_long) ntohl(sav->spi)));
  793                 m = NULL;               /* NB: free'd by m_pad */
  794                 error = ENOBUFS;
  795                 goto bad;
  796         }
  797 
  798         /*
  799          * Add padding: random, zero, or self-describing.
  800          * XXX catch unexpected setting
  801          */
  802         switch (sav->flags & SADB_X_EXT_PMASK) {
  803         case SADB_X_EXT_PRAND:
  804                 (void) read_random(pad, padding - 2);
  805                 break;
  806         case SADB_X_EXT_PZERO:
  807                 bzero(pad, padding - 2);
  808                 break;
  809         case SADB_X_EXT_PSEQ:
  810                 for (i = 0; i < padding - 2; i++)
  811                         pad[i] = i+1;
  812                 break;
  813         }
  814 
  815         /* Fix padding length and Next Protocol in padding itself. */
  816         pad[padding - 2] = padding - 2;
  817         m_copydata(m, protoff, sizeof(u_int8_t), pad + padding - 1);
  818 
  819         /* Fix Next Protocol in IPv4/IPv6 header. */
  820         prot = IPPROTO_ESP;
  821         m_copyback(m, protoff, sizeof(u_int8_t), (u_char *) &prot);
  822 
  823         /* Get crypto descriptors. */
  824         crp = crypto_getreq(esph != NULL ? 2 : 1);
  825         if (crp == NULL) {
  826                 DPRINTF(("%s: failed to acquire crypto descriptors\n",
  827                         __func__));
  828                 ESPSTAT_INC(esps_crypto);
  829                 error = ENOBUFS;
  830                 goto bad;
  831         }
  832 
  833         /* IPsec-specific opaque crypto info. */
  834         xd =  malloc(sizeof(struct xform_data), M_XDATA, M_NOWAIT | M_ZERO);
  835         if (xd == NULL) {
  836                 crypto_freereq(crp);
  837                 DPRINTF(("%s: failed to allocate xform_data\n", __func__));
  838                 ESPSTAT_INC(esps_crypto);
  839                 error = ENOBUFS;
  840                 goto bad;
  841         }
  842 
  843         crde = crp->crp_desc;
  844         crda = crde->crd_next;
  845 
  846         /* Encryption descriptor. */
  847         crde->crd_skip = skip + hlen;
  848         crde->crd_len = m->m_pkthdr.len - (skip + hlen + alen);
  849         crde->crd_flags = CRD_F_ENCRYPT;
  850         crde->crd_inject = skip + hlen - sav->ivlen;
  851 
  852         /* Encryption operation. */
  853         crde->crd_alg = espx->type;
  854         if (SAV_ISCTRORGCM(sav)) {
  855                 ivp = &crde->crd_iv[0];
  856 
  857                 /* GCM IV Format: RFC4106 4 */
  858                 /* CTR IV Format: RFC3686 4 */
  859                 /* Salt is last four bytes of key, RFC4106 8.1 */
  860                 /* Nonce is last four bytes of key, RFC3686 5.1 */
  861                 memcpy(ivp, sav->key_enc->key_data +
  862                     _KEYLEN(sav->key_enc) - 4, 4);
  863                 be64enc(&ivp[4], cntr);
  864                 if (SAV_ISCTR(sav)) {
  865                         /* Initial block counter is 1, RFC3686 4 */
  866                         /* XXXAE: should we use this only for first packet? */
  867                         be32enc(&ivp[sav->ivlen + 4], 1);
  868                 }
  869 
  870                 m_copyback(m, skip + hlen - sav->ivlen, sav->ivlen, &ivp[4]);
  871                 crde->crd_flags |= CRD_F_IV_EXPLICIT|CRD_F_IV_PRESENT;
  872         }
  873 
  874         /* Callback parameters */
  875         xd->sp = sp;
  876         xd->sav = sav;
  877         xd->idx = idx;
  878         xd->cryptoid = cryptoid;
  879         xd->vnet = curvnet;
  880 
  881         /* Crypto operation descriptor. */
  882         crp->crp_ilen = m->m_pkthdr.len; /* Total input length. */
  883         crp->crp_flags = CRYPTO_F_IMBUF | CRYPTO_F_CBIFSYNC;
  884         crp->crp_buf = (caddr_t) m;
  885         crp->crp_callback = esp_output_cb;
  886         crp->crp_opaque = (caddr_t) xd;
  887         crp->crp_sid = cryptoid;
  888 
  889         if (esph) {
  890                 /* Authentication descriptor. */
  891                 crda->crd_alg = esph->type;
  892                 crda->crd_skip = skip;
  893                 if (SAV_ISGCM(sav))
  894                         crda->crd_len = 8;      /* RFC4106 5, SPI + SN */
  895                 else
  896                         crda->crd_len = m->m_pkthdr.len - (skip + alen);
  897                 crda->crd_inject = m->m_pkthdr.len - alen;
  898         }
  899 
  900         return crypto_dispatch(crp);
  901 bad:
  902         if (m)
  903                 m_freem(m);
  904         key_freesav(&sav);
  905         key_freesp(&sp);
  906         return (error);
  907 }
  908 /*
  909  * ESP output callback from the crypto driver.
  910  */
  911 static int
  912 esp_output_cb(struct cryptop *crp)
  913 {
  914         struct xform_data *xd;
  915         struct secpolicy *sp;
  916         struct secasvar *sav;
  917         struct mbuf *m;
  918         uint64_t cryptoid;
  919         u_int idx;
  920         int error;
  921 
  922         xd = (struct xform_data *) crp->crp_opaque;
  923         CURVNET_SET(xd->vnet);
  924         m = (struct mbuf *) crp->crp_buf;
  925         sp = xd->sp;
  926         sav = xd->sav;
  927         idx = xd->idx;
  928         cryptoid = xd->cryptoid;
  929 
  930         /* Check for crypto errors. */
  931         if (crp->crp_etype) {
  932                 if (crp->crp_etype == EAGAIN) {
  933                         /* Reset the session ID */
  934                         if (ipsec_updateid(sav, &crp->crp_sid, &cryptoid) != 0)
  935                                 crypto_freesession(cryptoid);
  936                         xd->cryptoid = crp->crp_sid;
  937                         CURVNET_RESTORE();
  938                         return (crypto_dispatch(crp));
  939                 }
  940                 ESPSTAT_INC(esps_noxform);
  941                 DPRINTF(("%s: crypto error %d\n", __func__, crp->crp_etype));
  942                 error = crp->crp_etype;
  943                 m_freem(m);
  944                 goto bad;
  945         }
  946 
  947         /* Shouldn't happen... */
  948         if (m == NULL) {
  949                 ESPSTAT_INC(esps_crypto);
  950                 DPRINTF(("%s: bogus returned buffer from crypto\n", __func__));
  951                 error = EINVAL;
  952                 goto bad;
  953         }
  954         free(xd, M_XDATA);
  955         crypto_freereq(crp);
  956         ESPSTAT_INC(esps_hist[sav->alg_enc]);
  957         if (sav->tdb_authalgxform != NULL)
  958                 AHSTAT_INC(ahs_hist[sav->alg_auth]);
  959 
  960 #ifdef REGRESSION
  961         /* Emulate man-in-the-middle attack when ipsec_integrity is TRUE. */
  962         if (V_ipsec_integrity) {
  963                 static unsigned char ipseczeroes[AH_HMAC_MAXHASHLEN];
  964                 const struct auth_hash *esph;
  965 
  966                 /*
  967                  * Corrupt HMAC if we want to test integrity verification of
  968                  * the other side.
  969                  */
  970                 esph = sav->tdb_authalgxform;
  971                 if (esph !=  NULL) {
  972                         int alen;
  973 
  974                         alen = xform_ah_authsize(esph);
  975                         m_copyback(m, m->m_pkthdr.len - alen,
  976                             alen, ipseczeroes);
  977                 }
  978         }
  979 #endif
  980 
  981         /* NB: m is reclaimed by ipsec_process_done. */
  982         error = ipsec_process_done(m, sp, sav, idx);
  983         CURVNET_RESTORE();
  984         return (error);
  985 bad:
  986         CURVNET_RESTORE();
  987         free(xd, M_XDATA);
  988         crypto_freereq(crp);
  989         key_freesav(&sav);
  990         key_freesp(&sp);
  991         return (error);
  992 }
  993 
  994 static struct xformsw esp_xformsw = {
  995         .xf_type =      XF_ESP,
  996         .xf_name =      "IPsec ESP",
  997         .xf_init =      esp_init,
  998         .xf_zeroize =   esp_zeroize,
  999         .xf_input =     esp_input,
 1000         .xf_output =    esp_output,
 1001 };
 1002 
 1003 SYSINIT(esp_xform_init, SI_SUB_PROTO_DOMAIN, SI_ORDER_MIDDLE,
 1004     xform_attach, &esp_xformsw);
 1005 SYSUNINIT(esp_xform_uninit, SI_SUB_PROTO_DOMAIN, SI_ORDER_MIDDLE,
 1006     xform_detach, &esp_xformsw);

Cache object: 1b0a7bdaed0d6c69f9d95bf4f18a7591


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