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

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    1 /*      $FreeBSD: releng/10.4/sys/netipsec/xform_esp.c 283901 2015-06-02 03:14:42Z ae $ */
    2 /*      $OpenBSD: ip_esp.c,v 1.69 2001/06/26 06:18:59 angelos Exp $ */
    3 /*-
    4  * The authors of this code are John Ioannidis (ji@tla.org),
    5  * Angelos D. Keromytis (kermit@csd.uch.gr) and
    6  * Niels Provos (provos@physnet.uni-hamburg.de).
    7  *
    8  * The original version of this code was written by John Ioannidis
    9  * for BSD/OS in Athens, Greece, in November 1995.
   10  *
   11  * Ported to OpenBSD and NetBSD, with additional transforms, in December 1996,
   12  * by Angelos D. Keromytis.
   13  *
   14  * Additional transforms and features in 1997 and 1998 by Angelos D. Keromytis
   15  * and Niels Provos.
   16  *
   17  * Additional features in 1999 by Angelos D. Keromytis.
   18  *
   19  * Copyright (C) 1995, 1996, 1997, 1998, 1999 by John Ioannidis,
   20  * Angelos D. Keromytis and Niels Provos.
   21  * Copyright (c) 2001 Angelos D. Keromytis.
   22  *
   23  * Permission to use, copy, and modify this software with or without fee
   24  * is hereby granted, provided that this entire notice is included in
   25  * all copies of any software which is or includes a copy or
   26  * modification of this software.
   27  * You may use this code under the GNU public license if you so wish. Please
   28  * contribute changes back to the authors under this freer than GPL license
   29  * so that we may further the use of strong encryption without limitations to
   30  * all.
   31  *
   32  * THIS SOFTWARE IS BEING PROVIDED "AS IS", WITHOUT ANY EXPRESS OR
   33  * IMPLIED WARRANTY. IN PARTICULAR, NONE OF THE AUTHORS MAKES ANY
   34  * REPRESENTATION OR WARRANTY OF ANY KIND CONCERNING THE
   35  * MERCHANTABILITY OF THIS SOFTWARE OR ITS FITNESS FOR ANY PARTICULAR
   36  * PURPOSE.
   37  */
   38 #include "opt_inet.h"
   39 #include "opt_inet6.h"
   40 
   41 #include <sys/param.h>
   42 #include <sys/systm.h>
   43 #include <sys/mbuf.h>
   44 #include <sys/socket.h>
   45 #include <sys/syslog.h>
   46 #include <sys/kernel.h>
   47 #include <sys/random.h>
   48 #include <sys/sysctl.h>
   49 
   50 #include <net/if.h>
   51 #include <net/vnet.h>
   52 
   53 #include <netinet/in.h>
   54 #include <netinet/in_systm.h>
   55 #include <netinet/ip.h>
   56 #include <netinet/ip_ecn.h>
   57 #include <netinet/ip6.h>
   58 
   59 #include <netipsec/ipsec.h>
   60 #include <netipsec/ah.h>
   61 #include <netipsec/ah_var.h>
   62 #include <netipsec/esp.h>
   63 #include <netipsec/esp_var.h>
   64 #include <netipsec/xform.h>
   65 
   66 #ifdef INET6
   67 #include <netinet6/ip6_var.h>
   68 #include <netipsec/ipsec6.h>
   69 #include <netinet6/ip6_ecn.h>
   70 #endif
   71 
   72 #include <netipsec/key.h>
   73 #include <netipsec/key_debug.h>
   74 
   75 #include <opencrypto/cryptodev.h>
   76 #include <opencrypto/xform.h>
   77 
   78 VNET_DEFINE(int, esp_enable) = 1;
   79 VNET_PCPUSTAT_DEFINE(struct espstat, espstat);
   80 VNET_PCPUSTAT_SYSINIT(espstat);
   81 
   82 #ifdef VIMAGE
   83 VNET_PCPUSTAT_SYSUNINIT(espstat);
   84 #endif /* VIMAGE */
   85 
   86 SYSCTL_DECL(_net_inet_esp);
   87 SYSCTL_VNET_INT(_net_inet_esp, OID_AUTO,
   88         esp_enable,     CTLFLAG_RW,     &VNET_NAME(esp_enable), 0, "");
   89 SYSCTL_VNET_PCPUSTAT(_net_inet_esp, IPSECCTL_STATS, stats,
   90     struct espstat, espstat,
   91     "ESP statistics (struct espstat, netipsec/esp_var.h");
   92 
   93 static int esp_input_cb(struct cryptop *op);
   94 static int esp_output_cb(struct cryptop *crp);
   95 
   96 /*
   97  * NB: this is public for use by the PF_KEY support.
   98  * NB: if you add support here; be sure to add code to esp_attach below!
   99  */
  100 struct enc_xform *
  101 esp_algorithm_lookup(int alg)
  102 {
  103         if (alg >= ESP_ALG_MAX)
  104                 return NULL;
  105         switch (alg) {
  106         case SADB_EALG_DESCBC:
  107                 return &enc_xform_des;
  108         case SADB_EALG_3DESCBC:
  109                 return &enc_xform_3des;
  110         case SADB_X_EALG_AES:
  111                 return &enc_xform_rijndael128;
  112         case SADB_X_EALG_BLOWFISHCBC:
  113                 return &enc_xform_blf;
  114         case SADB_X_EALG_CAST128CBC:
  115                 return &enc_xform_cast5;
  116         case SADB_X_EALG_SKIPJACK:
  117                 return &enc_xform_skipjack;
  118         case SADB_EALG_NULL:
  119                 return &enc_xform_null;
  120         case SADB_X_EALG_CAMELLIACBC:
  121                 return &enc_xform_camellia;
  122         }
  123         return NULL;
  124 }
  125 
  126 size_t
  127 esp_hdrsiz(struct secasvar *sav)
  128 {
  129         size_t size;
  130 
  131         if (sav != NULL) {
  132                 /*XXX not right for null algorithm--does it matter??*/
  133                 IPSEC_ASSERT(sav->tdb_encalgxform != NULL,
  134                         ("SA with null xform"));
  135                 if (sav->flags & SADB_X_EXT_OLD)
  136                         size = sizeof (struct esp);
  137                 else
  138                         size = sizeof (struct newesp);
  139                 size += sav->tdb_encalgxform->blocksize + 9;
  140                 /*XXX need alg check???*/
  141                 if (sav->tdb_authalgxform != NULL && sav->replay)
  142                         size += ah_hdrsiz(sav);
  143         } else {
  144                 /*
  145                  *   base header size
  146                  * + max iv length for CBC mode
  147                  * + max pad length
  148                  * + sizeof (pad length field)
  149                  * + sizeof (next header field)
  150                  * + max icv supported.
  151                  */
  152                 size = sizeof (struct newesp) + EALG_MAX_BLOCK_LEN + 9 + 16;
  153         }
  154         return size;
  155 }
  156 
  157 /*
  158  * esp_init() is called when an SPI is being set up.
  159  */
  160 static int
  161 esp_init(struct secasvar *sav, struct xformsw *xsp)
  162 {
  163         struct enc_xform *txform;
  164         struct cryptoini cria, crie;
  165         int keylen;
  166         int error;
  167 
  168         txform = esp_algorithm_lookup(sav->alg_enc);
  169         if (txform == NULL) {
  170                 DPRINTF(("%s: unsupported encryption algorithm %d\n",
  171                         __func__, sav->alg_enc));
  172                 return EINVAL;
  173         }
  174         if (sav->key_enc == NULL) {
  175                 DPRINTF(("%s: no encoding key for %s algorithm\n",
  176                          __func__, txform->name));
  177                 return EINVAL;
  178         }
  179         if ((sav->flags&(SADB_X_EXT_OLD|SADB_X_EXT_IV4B)) == SADB_X_EXT_IV4B) {
  180                 DPRINTF(("%s: 4-byte IV not supported with protocol\n",
  181                         __func__));
  182                 return EINVAL;
  183         }
  184         keylen = _KEYLEN(sav->key_enc);
  185         if (txform->minkey > keylen || keylen > txform->maxkey) {
  186                 DPRINTF(("%s: invalid key length %u, must be in the range "
  187                         "[%u..%u] for algorithm %s\n", __func__,
  188                         keylen, txform->minkey, txform->maxkey,
  189                         txform->name));
  190                 return EINVAL;
  191         }
  192 
  193         /*
  194          * NB: The null xform needs a non-zero blocksize to keep the
  195          *      crypto code happy but if we use it to set ivlen then
  196          *      the ESP header will be processed incorrectly.  The
  197          *      compromise is to force it to zero here.
  198          */
  199         sav->ivlen = (txform == &enc_xform_null ? 0 : txform->blocksize);
  200         sav->iv = (caddr_t) malloc(sav->ivlen, M_XDATA, M_WAITOK);
  201         key_randomfill(sav->iv, sav->ivlen);    /*XXX*/
  202 
  203         /*
  204          * Setup AH-related state.
  205          */
  206         if (sav->alg_auth != 0) {
  207                 error = ah_init0(sav, xsp, &cria);
  208                 if (error)
  209                         return error;
  210         }
  211 
  212         /* NB: override anything set in ah_init0 */
  213         sav->tdb_xform = xsp;
  214         sav->tdb_encalgxform = txform;
  215 
  216         /* Initialize crypto session. */
  217         bzero(&crie, sizeof (crie));
  218         crie.cri_alg = sav->tdb_encalgxform->type;
  219         crie.cri_klen = _KEYBITS(sav->key_enc);
  220         crie.cri_key = sav->key_enc->key_data;
  221         /* XXX Rounds ? */
  222 
  223         if (sav->tdb_authalgxform && sav->tdb_encalgxform) {
  224                 /* init both auth & enc */
  225                 crie.cri_next = &cria;
  226                 error = crypto_newsession(&sav->tdb_cryptoid,
  227                                           &crie, V_crypto_support);
  228         } else if (sav->tdb_encalgxform) {
  229                 error = crypto_newsession(&sav->tdb_cryptoid,
  230                                           &crie, V_crypto_support);
  231         } else if (sav->tdb_authalgxform) {
  232                 error = crypto_newsession(&sav->tdb_cryptoid,
  233                                           &cria, V_crypto_support);
  234         } else {
  235                 /* XXX cannot happen? */
  236                 DPRINTF(("%s: no encoding OR authentication xform!\n",
  237                         __func__));
  238                 error = EINVAL;
  239         }
  240         return error;
  241 }
  242 
  243 /*
  244  * Paranoia.
  245  */
  246 static int
  247 esp_zeroize(struct secasvar *sav)
  248 {
  249         /* NB: ah_zerorize free's the crypto session state */
  250         int error = ah_zeroize(sav);
  251 
  252         if (sav->key_enc)
  253                 bzero(sav->key_enc->key_data, _KEYLEN(sav->key_enc));
  254         if (sav->iv) {
  255                 free(sav->iv, M_XDATA);
  256                 sav->iv = NULL;
  257         }
  258         sav->tdb_encalgxform = NULL;
  259         sav->tdb_xform = NULL;
  260         return error;
  261 }
  262 
  263 /*
  264  * ESP input processing, called (eventually) through the protocol switch.
  265  */
  266 static int
  267 esp_input(struct mbuf *m, struct secasvar *sav, int skip, int protoff)
  268 {
  269         struct auth_hash *esph;
  270         struct enc_xform *espx;
  271         struct tdb_ident *tdbi;
  272         struct tdb_crypto *tc;
  273         int plen, alen, hlen;
  274         struct m_tag *mtag;
  275         struct newesp *esp;
  276 
  277         struct cryptodesc *crde;
  278         struct cryptop *crp;
  279 
  280         IPSEC_ASSERT(sav != NULL, ("null SA"));
  281         IPSEC_ASSERT(sav->tdb_encalgxform != NULL, ("null encoding xform"));
  282 
  283         /* Valid IP Packet length ? */
  284         if ( (skip&3) || (m->m_pkthdr.len&3) ){
  285                 DPRINTF(("%s: misaligned packet, skip %u pkt len %u",
  286                                 __func__, skip, m->m_pkthdr.len));
  287                 ESPSTAT_INC(esps_badilen);
  288                 m_freem(m);
  289                 return EINVAL;
  290         }
  291 
  292         /* XXX don't pullup, just copy header */
  293         IP6_EXTHDR_GET(esp, struct newesp *, m, skip, sizeof (struct newesp));
  294 
  295         esph = sav->tdb_authalgxform;
  296         espx = sav->tdb_encalgxform;
  297 
  298         /* Determine the ESP header length */
  299         if (sav->flags & SADB_X_EXT_OLD)
  300                 hlen = sizeof (struct esp) + sav->ivlen;
  301         else
  302                 hlen = sizeof (struct newesp) + sav->ivlen;
  303         /* Authenticator hash size */
  304         if (esph != NULL) {
  305                 switch (esph->type) {
  306                 case CRYPTO_SHA2_256_HMAC:
  307                 case CRYPTO_SHA2_384_HMAC:
  308                 case CRYPTO_SHA2_512_HMAC:
  309                         alen = esph->hashsize/2;
  310                         break;
  311                 default:
  312                         alen = AH_HMAC_HASHLEN;
  313                         break;
  314                 }
  315         }else
  316                 alen = 0;
  317 
  318         /*
  319          * Verify payload length is multiple of encryption algorithm
  320          * block size.
  321          *
  322          * NB: This works for the null algorithm because the blocksize
  323          *     is 4 and all packets must be 4-byte aligned regardless
  324          *     of the algorithm.
  325          */
  326         plen = m->m_pkthdr.len - (skip + hlen + alen);
  327         if ((plen & (espx->blocksize - 1)) || (plen <= 0)) {
  328                 DPRINTF(("%s: payload of %d octets not a multiple of %d octets,"
  329                     "  SA %s/%08lx\n", __func__,
  330                     plen, espx->blocksize,
  331                     ipsec_address(&sav->sah->saidx.dst),
  332                     (u_long) ntohl(sav->spi)));
  333                 ESPSTAT_INC(esps_badilen);
  334                 m_freem(m);
  335                 return EINVAL;
  336         }
  337 
  338         /*
  339          * Check sequence number.
  340          */
  341         if (esph && sav->replay && !ipsec_chkreplay(ntohl(esp->esp_seq), sav)) {
  342                 DPRINTF(("%s: packet replay check for %s\n", __func__,
  343                     ipsec_logsastr(sav)));      /*XXX*/
  344                 ESPSTAT_INC(esps_replay);
  345                 m_freem(m);
  346                 return ENOBUFS;         /*XXX*/
  347         }
  348 
  349         /* Update the counters */
  350         ESPSTAT_ADD(esps_ibytes, m->m_pkthdr.len - (skip + hlen + alen));
  351 
  352         /* Find out if we've already done crypto */
  353         for (mtag = m_tag_find(m, PACKET_TAG_IPSEC_IN_CRYPTO_DONE, NULL);
  354              mtag != NULL;
  355              mtag = m_tag_find(m, PACKET_TAG_IPSEC_IN_CRYPTO_DONE, mtag)) {
  356                 tdbi = (struct tdb_ident *) (mtag + 1);
  357                 if (tdbi->proto == sav->sah->saidx.proto &&
  358                     tdbi->spi == sav->spi &&
  359                     !bcmp(&tdbi->dst, &sav->sah->saidx.dst,
  360                           sizeof(union sockaddr_union)))
  361                         break;
  362         }
  363 
  364         /* Get crypto descriptors */
  365         crp = crypto_getreq(esph && espx ? 2 : 1);
  366         if (crp == NULL) {
  367                 DPRINTF(("%s: failed to acquire crypto descriptors\n",
  368                         __func__));
  369                 ESPSTAT_INC(esps_crypto);
  370                 m_freem(m);
  371                 return ENOBUFS;
  372         }
  373 
  374         /* Get IPsec-specific opaque pointer */
  375         if (esph == NULL || mtag != NULL)
  376                 tc = (struct tdb_crypto *) malloc(sizeof(struct tdb_crypto),
  377                     M_XDATA, M_NOWAIT|M_ZERO);
  378         else
  379                 tc = (struct tdb_crypto *) malloc(sizeof(struct tdb_crypto) + alen,
  380                     M_XDATA, M_NOWAIT|M_ZERO);
  381         if (tc == NULL) {
  382                 crypto_freereq(crp);
  383                 DPRINTF(("%s: failed to allocate tdb_crypto\n", __func__));
  384                 ESPSTAT_INC(esps_crypto);
  385                 m_freem(m);
  386                 return ENOBUFS;
  387         }
  388 
  389         tc->tc_ptr = (caddr_t) mtag;
  390 
  391         if (esph) {
  392                 struct cryptodesc *crda = crp->crp_desc;
  393 
  394                 IPSEC_ASSERT(crda != NULL, ("null ah crypto descriptor"));
  395 
  396                 /* Authentication descriptor */
  397                 crda->crd_skip = skip;
  398                 crda->crd_len = m->m_pkthdr.len - (skip + alen);
  399                 crda->crd_inject = m->m_pkthdr.len - alen;
  400 
  401                 crda->crd_alg = esph->type;
  402                 crda->crd_key = sav->key_auth->key_data;
  403                 crda->crd_klen = _KEYBITS(sav->key_auth);
  404 
  405                 /* Copy the authenticator */
  406                 if (mtag == NULL)
  407                         m_copydata(m, m->m_pkthdr.len - alen, alen,
  408                                    (caddr_t) (tc + 1));
  409 
  410                 /* Chain authentication request */
  411                 crde = crda->crd_next;
  412         } else {
  413                 crde = crp->crp_desc;
  414         }
  415 
  416         /* Crypto operation descriptor */
  417         crp->crp_ilen = m->m_pkthdr.len; /* Total input length */
  418         crp->crp_flags = CRYPTO_F_IMBUF | CRYPTO_F_CBIFSYNC;
  419         crp->crp_buf = (caddr_t) m;
  420         crp->crp_callback = esp_input_cb;
  421         crp->crp_sid = sav->tdb_cryptoid;
  422         crp->crp_opaque = (caddr_t) tc;
  423 
  424         /* These are passed as-is to the callback */
  425         tc->tc_spi = sav->spi;
  426         tc->tc_dst = sav->sah->saidx.dst;
  427         tc->tc_proto = sav->sah->saidx.proto;
  428         tc->tc_protoff = protoff;
  429         tc->tc_skip = skip;
  430         KEY_ADDREFSA(sav);
  431         tc->tc_sav = sav;
  432 
  433         /* Decryption descriptor */
  434         if (espx) {
  435                 IPSEC_ASSERT(crde != NULL, ("null esp crypto descriptor"));
  436                 crde->crd_skip = skip + hlen;
  437                 crde->crd_len = m->m_pkthdr.len - (skip + hlen + alen);
  438                 crde->crd_inject = skip + hlen - sav->ivlen;
  439 
  440                 crde->crd_alg = espx->type;
  441                 crde->crd_key = sav->key_enc->key_data;
  442                 crde->crd_klen = _KEYBITS(sav->key_enc);
  443                 /* XXX Rounds ? */
  444         }
  445 
  446         if (mtag == NULL)
  447                 return crypto_dispatch(crp);
  448         else
  449                 return esp_input_cb(crp);
  450 }
  451 
  452 /*
  453  * ESP input callback from the crypto driver.
  454  */
  455 static int
  456 esp_input_cb(struct cryptop *crp)
  457 {
  458         u_int8_t lastthree[3], aalg[AH_HMAC_MAXHASHLEN];
  459         int hlen, skip, protoff, error, alen;
  460         struct mbuf *m;
  461         struct cryptodesc *crd;
  462         struct auth_hash *esph;
  463         struct enc_xform *espx;
  464         struct tdb_crypto *tc;
  465         struct m_tag *mtag;
  466         struct secasvar *sav;
  467         struct secasindex *saidx;
  468         caddr_t ptr;
  469 
  470         crd = crp->crp_desc;
  471         IPSEC_ASSERT(crd != NULL, ("null crypto descriptor!"));
  472 
  473         tc = (struct tdb_crypto *) crp->crp_opaque;
  474         IPSEC_ASSERT(tc != NULL, ("null opaque crypto data area!"));
  475         skip = tc->tc_skip;
  476         protoff = tc->tc_protoff;
  477         mtag = (struct m_tag *) tc->tc_ptr;
  478         m = (struct mbuf *) crp->crp_buf;
  479 
  480         sav = tc->tc_sav;
  481         IPSEC_ASSERT(sav != NULL, ("null SA!"));
  482 
  483         saidx = &sav->sah->saidx;
  484         IPSEC_ASSERT(saidx->dst.sa.sa_family == AF_INET ||
  485                 saidx->dst.sa.sa_family == AF_INET6,
  486                 ("unexpected protocol family %u", saidx->dst.sa.sa_family));
  487 
  488         esph = sav->tdb_authalgxform;
  489         espx = sav->tdb_encalgxform;
  490 
  491         /* Check for crypto errors */
  492         if (crp->crp_etype) {
  493                 /* Reset the session ID */
  494                 if (sav->tdb_cryptoid != 0)
  495                         sav->tdb_cryptoid = crp->crp_sid;
  496 
  497                 if (crp->crp_etype == EAGAIN)
  498                         return (crypto_dispatch(crp));
  499 
  500                 ESPSTAT_INC(esps_noxform);
  501                 DPRINTF(("%s: crypto error %d\n", __func__, crp->crp_etype));
  502                 error = crp->crp_etype;
  503                 goto bad;
  504         }
  505 
  506         /* Shouldn't happen... */
  507         if (m == NULL) {
  508                 ESPSTAT_INC(esps_crypto);
  509                 DPRINTF(("%s: bogus returned buffer from crypto\n", __func__));
  510                 error = EINVAL;
  511                 goto bad;
  512         }
  513         ESPSTAT_INC(esps_hist[sav->alg_enc]);
  514 
  515         /* If authentication was performed, check now. */
  516         if (esph != NULL) {
  517                 switch (esph->type) {
  518                 case CRYPTO_SHA2_256_HMAC:
  519                 case CRYPTO_SHA2_384_HMAC:
  520                 case CRYPTO_SHA2_512_HMAC:
  521                         alen = esph->hashsize/2;
  522                         break;
  523                 default:
  524                         alen = AH_HMAC_HASHLEN;
  525                         break;
  526                 }
  527                 /*
  528                  * If we have a tag, it means an IPsec-aware NIC did
  529                  * the verification for us.  Otherwise we need to
  530                  * check the authentication calculation.
  531                  */
  532                 AHSTAT_INC(ahs_hist[sav->alg_auth]);
  533                 if (mtag == NULL) {
  534                         /* Copy the authenticator from the packet */
  535                         m_copydata(m, m->m_pkthdr.len - alen,
  536                                 alen, aalg);
  537 
  538                         ptr = (caddr_t) (tc + 1);
  539 
  540                         /* Verify authenticator */
  541                         if (bcmp(ptr, aalg, alen) != 0) {
  542                                 DPRINTF(("%s: "
  543                     "authentication hash mismatch for packet in SA %s/%08lx\n",
  544                                     __func__,
  545                                     ipsec_address(&saidx->dst),
  546                                     (u_long) ntohl(sav->spi)));
  547                                 ESPSTAT_INC(esps_badauth);
  548                                 error = EACCES;
  549                                 goto bad;
  550                         }
  551                 }
  552 
  553                 /* Remove trailing authenticator */
  554                 m_adj(m, -alen);
  555         }
  556 
  557         /* Release the crypto descriptors */
  558         free(tc, M_XDATA), tc = NULL;
  559         crypto_freereq(crp), crp = NULL;
  560 
  561         /*
  562          * Packet is now decrypted.
  563          */
  564         m->m_flags |= M_DECRYPTED;
  565 
  566         /*
  567          * Update replay sequence number, if appropriate.
  568          */
  569         if (sav->replay) {
  570                 u_int32_t seq;
  571 
  572                 m_copydata(m, skip + offsetof(struct newesp, esp_seq),
  573                            sizeof (seq), (caddr_t) &seq);
  574                 if (ipsec_updatereplay(ntohl(seq), sav)) {
  575                         DPRINTF(("%s: packet replay check for %s\n", __func__,
  576                             ipsec_logsastr(sav)));
  577                         ESPSTAT_INC(esps_replay);
  578                         error = ENOBUFS;
  579                         goto bad;
  580                 }
  581         }
  582 
  583         /* Determine the ESP header length */
  584         if (sav->flags & SADB_X_EXT_OLD)
  585                 hlen = sizeof (struct esp) + sav->ivlen;
  586         else
  587                 hlen = sizeof (struct newesp) + sav->ivlen;
  588 
  589         /* Remove the ESP header and IV from the mbuf. */
  590         error = m_striphdr(m, skip, hlen);
  591         if (error) {
  592                 ESPSTAT_INC(esps_hdrops);
  593                 DPRINTF(("%s: bad mbuf chain, SA %s/%08lx\n", __func__,
  594                     ipsec_address(&sav->sah->saidx.dst),
  595                     (u_long) ntohl(sav->spi)));
  596                 goto bad;
  597         }
  598 
  599         /* Save the last three bytes of decrypted data */
  600         m_copydata(m, m->m_pkthdr.len - 3, 3, lastthree);
  601 
  602         /* Verify pad length */
  603         if (lastthree[1] + 2 > m->m_pkthdr.len - skip) {
  604                 ESPSTAT_INC(esps_badilen);
  605                 DPRINTF(("%s: invalid padding length %d for %u byte packet "
  606                         "in SA %s/%08lx\n", __func__,
  607                          lastthree[1], m->m_pkthdr.len - skip,
  608                          ipsec_address(&sav->sah->saidx.dst),
  609                          (u_long) ntohl(sav->spi)));
  610                 error = EINVAL;
  611                 goto bad;
  612         }
  613 
  614         /* Verify correct decryption by checking the last padding bytes */
  615         if ((sav->flags & SADB_X_EXT_PMASK) != SADB_X_EXT_PRAND) {
  616                 if (lastthree[1] != lastthree[0] && lastthree[1] != 0) {
  617                         ESPSTAT_INC(esps_badenc);
  618                         DPRINTF(("%s: decryption failed for packet in "
  619                                 "SA %s/%08lx\n", __func__,
  620                                 ipsec_address(&sav->sah->saidx.dst),
  621                                 (u_long) ntohl(sav->spi)));
  622                         error = EINVAL;
  623                         goto bad;
  624                 }
  625         }
  626 
  627         /* Trim the mbuf chain to remove trailing authenticator and padding */
  628         m_adj(m, -(lastthree[1] + 2));
  629 
  630         /* Restore the Next Protocol field */
  631         m_copyback(m, protoff, sizeof (u_int8_t), lastthree + 2);
  632 
  633         switch (saidx->dst.sa.sa_family) {
  634 #ifdef INET6
  635         case AF_INET6:
  636                 error = ipsec6_common_input_cb(m, sav, skip, protoff, mtag);
  637                 break;
  638 #endif
  639 #ifdef INET
  640         case AF_INET:
  641                 error = ipsec4_common_input_cb(m, sav, skip, protoff, mtag);
  642                 break;
  643 #endif
  644         default:
  645                 panic("%s: Unexpected address family: %d saidx=%p", __func__,
  646                     saidx->dst.sa.sa_family, saidx);
  647         }
  648 
  649         KEY_FREESAV(&sav);
  650         return error;
  651 bad:
  652         if (sav)
  653                 KEY_FREESAV(&sav);
  654         if (m != NULL)
  655                 m_freem(m);
  656         if (tc != NULL)
  657                 free(tc, M_XDATA);
  658         if (crp != NULL)
  659                 crypto_freereq(crp);
  660         return error;
  661 }
  662 
  663 /*
  664  * ESP output routine, called by ipsec[46]_process_packet().
  665  */
  666 static int
  667 esp_output(
  668         struct mbuf *m,
  669         struct ipsecrequest *isr,
  670         struct mbuf **mp,
  671         int skip,
  672         int protoff
  673 )
  674 {
  675         struct enc_xform *espx;
  676         struct auth_hash *esph;
  677         int hlen, rlen, padding, blks, alen, i, roff;
  678         struct mbuf *mo = (struct mbuf *) NULL;
  679         struct tdb_crypto *tc;
  680         struct secasvar *sav;
  681         struct secasindex *saidx;
  682         unsigned char *pad;
  683         u_int8_t prot;
  684         int error, maxpacketsize;
  685 
  686         struct cryptodesc *crde = NULL, *crda = NULL;
  687         struct cryptop *crp;
  688 
  689         sav = isr->sav;
  690         IPSEC_ASSERT(sav != NULL, ("null SA"));
  691         esph = sav->tdb_authalgxform;
  692         espx = sav->tdb_encalgxform;
  693         IPSEC_ASSERT(espx != NULL, ("null encoding xform"));
  694 
  695         if (sav->flags & SADB_X_EXT_OLD)
  696                 hlen = sizeof (struct esp) + sav->ivlen;
  697         else
  698                 hlen = sizeof (struct newesp) + sav->ivlen;
  699 
  700         rlen = m->m_pkthdr.len - skip;  /* Raw payload length. */
  701         /*
  702          * NB: The null encoding transform has a blocksize of 4
  703          *     so that headers are properly aligned.
  704          */
  705         blks = espx->blocksize;         /* IV blocksize */
  706 
  707         /* XXX clamp padding length a la KAME??? */
  708         padding = ((blks - ((rlen + 2) % blks)) % blks) + 2;
  709 
  710         if (esph)
  711                 switch (esph->type) {
  712                 case CRYPTO_SHA2_256_HMAC:
  713                 case CRYPTO_SHA2_384_HMAC:
  714                 case CRYPTO_SHA2_512_HMAC:
  715                         alen = esph->hashsize/2;
  716                         break;
  717                 default:
  718                 alen = AH_HMAC_HASHLEN;
  719                         break;
  720                 }
  721         else
  722                 alen = 0;
  723 
  724         ESPSTAT_INC(esps_output);
  725 
  726         saidx = &sav->sah->saidx;
  727         /* Check for maximum packet size violations. */
  728         switch (saidx->dst.sa.sa_family) {
  729 #ifdef INET
  730         case AF_INET:
  731                 maxpacketsize = IP_MAXPACKET;
  732                 break;
  733 #endif /* INET */
  734 #ifdef INET6
  735         case AF_INET6:
  736                 maxpacketsize = IPV6_MAXPACKET;
  737                 break;
  738 #endif /* INET6 */
  739         default:
  740                 DPRINTF(("%s: unknown/unsupported protocol "
  741                     "family %d, SA %s/%08lx\n", __func__,
  742                     saidx->dst.sa.sa_family, ipsec_address(&saidx->dst),
  743                     (u_long) ntohl(sav->spi)));
  744                 ESPSTAT_INC(esps_nopf);
  745                 error = EPFNOSUPPORT;
  746                 goto bad;
  747         }
  748         if (skip + hlen + rlen + padding + alen > maxpacketsize) {
  749                 DPRINTF(("%s: packet in SA %s/%08lx got too big "
  750                     "(len %u, max len %u)\n", __func__,
  751                     ipsec_address(&saidx->dst), (u_long) ntohl(sav->spi),
  752                     skip + hlen + rlen + padding + alen, maxpacketsize));
  753                 ESPSTAT_INC(esps_toobig);
  754                 error = EMSGSIZE;
  755                 goto bad;
  756         }
  757 
  758         /* Update the counters. */
  759         ESPSTAT_ADD(esps_obytes, m->m_pkthdr.len - skip);
  760 
  761         m = m_unshare(m, M_NOWAIT);
  762         if (m == NULL) {
  763                 DPRINTF(("%s: cannot clone mbuf chain, SA %s/%08lx\n", __func__,
  764                     ipsec_address(&saidx->dst), (u_long) ntohl(sav->spi)));
  765                 ESPSTAT_INC(esps_hdrops);
  766                 error = ENOBUFS;
  767                 goto bad;
  768         }
  769 
  770         /* Inject ESP header. */
  771         mo = m_makespace(m, skip, hlen, &roff);
  772         if (mo == NULL) {
  773                 DPRINTF(("%s: %u byte ESP hdr inject failed for SA %s/%08lx\n",
  774                     __func__, hlen, ipsec_address(&saidx->dst),
  775                     (u_long) ntohl(sav->spi)));
  776                 ESPSTAT_INC(esps_hdrops);               /* XXX diffs from openbsd */
  777                 error = ENOBUFS;
  778                 goto bad;
  779         }
  780 
  781         /* Initialize ESP header. */
  782         bcopy((caddr_t) &sav->spi, mtod(mo, caddr_t) + roff, sizeof(u_int32_t));
  783         if (sav->replay) {
  784                 u_int32_t replay;
  785 
  786 #ifdef REGRESSION
  787                 /* Emulate replay attack when ipsec_replay is TRUE. */
  788                 if (!V_ipsec_replay)
  789 #endif
  790                         sav->replay->count++;
  791                 replay = htonl(sav->replay->count);
  792                 bcopy((caddr_t) &replay,
  793                     mtod(mo, caddr_t) + roff + sizeof(u_int32_t),
  794                     sizeof(u_int32_t));
  795         }
  796 
  797         /*
  798          * Add padding -- better to do it ourselves than use the crypto engine,
  799          * although if/when we support compression, we'd have to do that.
  800          */
  801         pad = (u_char *) m_pad(m, padding + alen);
  802         if (pad == NULL) {
  803                 DPRINTF(("%s: m_pad failed for SA %s/%08lx\n", __func__,
  804                     ipsec_address(&saidx->dst), (u_long) ntohl(sav->spi)));
  805                 m = NULL;               /* NB: free'd by m_pad */
  806                 error = ENOBUFS;
  807                 goto bad;
  808         }
  809 
  810         /*
  811          * Add padding: random, zero, or self-describing.
  812          * XXX catch unexpected setting
  813          */
  814         switch (sav->flags & SADB_X_EXT_PMASK) {
  815         case SADB_X_EXT_PRAND:
  816                 (void) read_random(pad, padding - 2);
  817                 break;
  818         case SADB_X_EXT_PZERO:
  819                 bzero(pad, padding - 2);
  820                 break;
  821         case SADB_X_EXT_PSEQ:
  822                 for (i = 0; i < padding - 2; i++)
  823                         pad[i] = i+1;
  824                 break;
  825         }
  826 
  827         /* Fix padding length and Next Protocol in padding itself. */
  828         pad[padding - 2] = padding - 2;
  829         m_copydata(m, protoff, sizeof(u_int8_t), pad + padding - 1);
  830 
  831         /* Fix Next Protocol in IPv4/IPv6 header. */
  832         prot = IPPROTO_ESP;
  833         m_copyback(m, protoff, sizeof(u_int8_t), (u_char *) &prot);
  834 
  835         /* Get crypto descriptors. */
  836         crp = crypto_getreq(esph && espx ? 2 : 1);
  837         if (crp == NULL) {
  838                 DPRINTF(("%s: failed to acquire crypto descriptors\n",
  839                         __func__));
  840                 ESPSTAT_INC(esps_crypto);
  841                 error = ENOBUFS;
  842                 goto bad;
  843         }
  844 
  845         if (espx) {
  846                 crde = crp->crp_desc;
  847                 crda = crde->crd_next;
  848 
  849                 /* Encryption descriptor. */
  850                 crde->crd_skip = skip + hlen;
  851                 crde->crd_len = m->m_pkthdr.len - (skip + hlen + alen);
  852                 crde->crd_flags = CRD_F_ENCRYPT;
  853                 crde->crd_inject = skip + hlen - sav->ivlen;
  854 
  855                 /* Encryption operation. */
  856                 crde->crd_alg = espx->type;
  857                 crde->crd_key = sav->key_enc->key_data;
  858                 crde->crd_klen = _KEYBITS(sav->key_enc);
  859                 /* XXX Rounds ? */
  860         } else
  861                 crda = crp->crp_desc;
  862 
  863         /* IPsec-specific opaque crypto info. */
  864         tc = (struct tdb_crypto *) malloc(sizeof(struct tdb_crypto),
  865                 M_XDATA, M_NOWAIT|M_ZERO);
  866         if (tc == NULL) {
  867                 crypto_freereq(crp);
  868                 DPRINTF(("%s: failed to allocate tdb_crypto\n", __func__));
  869                 ESPSTAT_INC(esps_crypto);
  870                 error = ENOBUFS;
  871                 goto bad;
  872         }
  873 
  874         /* Callback parameters */
  875         tc->tc_isr = isr;
  876         KEY_ADDREFSA(sav);
  877         tc->tc_sav = sav;
  878         tc->tc_spi = sav->spi;
  879         tc->tc_dst = saidx->dst;
  880         tc->tc_proto = saidx->proto;
  881 
  882         /* Crypto operation descriptor. */
  883         crp->crp_ilen = m->m_pkthdr.len; /* Total input length. */
  884         crp->crp_flags = CRYPTO_F_IMBUF | CRYPTO_F_CBIFSYNC;
  885         crp->crp_buf = (caddr_t) m;
  886         crp->crp_callback = esp_output_cb;
  887         crp->crp_opaque = (caddr_t) tc;
  888         crp->crp_sid = sav->tdb_cryptoid;
  889 
  890         if (esph) {
  891                 /* Authentication descriptor. */
  892                 crda->crd_skip = skip;
  893                 crda->crd_len = m->m_pkthdr.len - (skip + alen);
  894                 crda->crd_inject = m->m_pkthdr.len - alen;
  895 
  896                 /* Authentication operation. */
  897                 crda->crd_alg = esph->type;
  898                 crda->crd_key = sav->key_auth->key_data;
  899                 crda->crd_klen = _KEYBITS(sav->key_auth);
  900         }
  901 
  902         return crypto_dispatch(crp);
  903 bad:
  904         if (m)
  905                 m_freem(m);
  906         return (error);
  907 }
  908 
  909 /*
  910  * ESP output callback from the crypto driver.
  911  */
  912 static int
  913 esp_output_cb(struct cryptop *crp)
  914 {
  915         struct tdb_crypto *tc;
  916         struct ipsecrequest *isr;
  917         struct secasvar *sav;
  918         struct mbuf *m;
  919         int error;
  920 
  921         tc = (struct tdb_crypto *) crp->crp_opaque;
  922         IPSEC_ASSERT(tc != NULL, ("null opaque data area!"));
  923         m = (struct mbuf *) crp->crp_buf;
  924 
  925         isr = tc->tc_isr;
  926         IPSECREQUEST_LOCK(isr);
  927         sav = tc->tc_sav;
  928         /* With the isr lock released SA pointer can be updated. */
  929         if (sav != isr->sav) {
  930                 ESPSTAT_INC(esps_notdb);
  931                 DPRINTF(("%s: SA gone during crypto (SA %s/%08lx proto %u)\n",
  932                     __func__, ipsec_address(&tc->tc_dst),
  933                     (u_long) ntohl(tc->tc_spi), tc->tc_proto));
  934                 error = ENOBUFS;                /*XXX*/
  935                 goto bad;
  936         }
  937 
  938         /* Check for crypto errors. */
  939         if (crp->crp_etype) {
  940                 /* Reset session ID. */
  941                 if (sav->tdb_cryptoid != 0)
  942                         sav->tdb_cryptoid = crp->crp_sid;
  943 
  944                 if (crp->crp_etype == EAGAIN) {
  945                         IPSECREQUEST_UNLOCK(isr);
  946                         return (crypto_dispatch(crp));
  947                 }
  948 
  949                 ESPSTAT_INC(esps_noxform);
  950                 DPRINTF(("%s: crypto error %d\n", __func__, crp->crp_etype));
  951                 error = crp->crp_etype;
  952                 goto bad;
  953         }
  954 
  955         /* Shouldn't happen... */
  956         if (m == NULL) {
  957                 ESPSTAT_INC(esps_crypto);
  958                 DPRINTF(("%s: bogus returned buffer from crypto\n", __func__));
  959                 error = EINVAL;
  960                 goto bad;
  961         }
  962         ESPSTAT_INC(esps_hist[sav->alg_enc]);
  963         if (sav->tdb_authalgxform != NULL)
  964                 AHSTAT_INC(ahs_hist[sav->alg_auth]);
  965 
  966         /* Release crypto descriptors. */
  967         free(tc, M_XDATA);
  968         crypto_freereq(crp);
  969 
  970 #ifdef REGRESSION
  971         /* Emulate man-in-the-middle attack when ipsec_integrity is TRUE. */
  972         if (V_ipsec_integrity) {
  973                 static unsigned char ipseczeroes[AH_HMAC_MAXHASHLEN];
  974                 struct auth_hash *esph;
  975 
  976                 /*
  977                  * Corrupt HMAC if we want to test integrity verification of
  978                  * the other side.
  979                  */
  980                 esph = sav->tdb_authalgxform;
  981                 if (esph !=  NULL) {
  982                         int alen;
  983 
  984                         switch (esph->type) {
  985                         case CRYPTO_SHA2_256_HMAC:
  986                         case CRYPTO_SHA2_384_HMAC:
  987                         case CRYPTO_SHA2_512_HMAC:
  988                                 alen = esph->hashsize/2;
  989                                 break;
  990                         default:
  991                                 alen = AH_HMAC_HASHLEN;
  992                                 break;
  993                         }
  994                         m_copyback(m, m->m_pkthdr.len - alen,
  995                             alen, ipseczeroes);
  996                 }
  997         }
  998 #endif
  999 
 1000         /* NB: m is reclaimed by ipsec_process_done. */
 1001         error = ipsec_process_done(m, isr);
 1002         KEY_FREESAV(&sav);
 1003         IPSECREQUEST_UNLOCK(isr);
 1004         return error;
 1005 bad:
 1006         if (sav)
 1007                 KEY_FREESAV(&sav);
 1008         IPSECREQUEST_UNLOCK(isr);
 1009         if (m)
 1010                 m_freem(m);
 1011         free(tc, M_XDATA);
 1012         crypto_freereq(crp);
 1013         return error;
 1014 }
 1015 
 1016 static struct xformsw esp_xformsw = {
 1017         XF_ESP,         XFT_CONF|XFT_AUTH,      "IPsec ESP",
 1018         esp_init,       esp_zeroize,            esp_input,
 1019         esp_output
 1020 };
 1021 
 1022 static void
 1023 esp_attach(void)
 1024 {
 1025 
 1026         xform_register(&esp_xformsw);
 1027 }
 1028 SYSINIT(esp_xform_init, SI_SUB_PROTO_DOMAIN, SI_ORDER_MIDDLE, esp_attach, NULL);

Cache object: 763219361cbe31a6970d3024bf855548


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