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/5.2/sys/netipsec/xform_esp.c 120585 2003-09-29 22:57:43Z sam $ */
    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 
   52 #include <netinet/in.h>
   53 #include <netinet/in_systm.h>
   54 #include <netinet/ip.h>
   55 #include <netinet/ip_ecn.h>
   56 #include <netinet/ip6.h>
   57 
   58 #include <net/route.h>
   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 int     esp_enable = 1;
   79 struct  espstat espstat;
   80 
   81 SYSCTL_DECL(_net_inet_esp);
   82 SYSCTL_INT(_net_inet_esp, OID_AUTO,
   83         esp_enable,     CTLFLAG_RW,     &esp_enable,    0, "");
   84 SYSCTL_STRUCT(_net_inet_esp, IPSECCTL_STATS,
   85         stats,          CTLFLAG_RD,     &espstat,       espstat, "");
   86 
   87 static  int esp_max_ivlen;              /* max iv length over all algorithms */
   88 
   89 static int esp_input_cb(struct cryptop *op);
   90 static int esp_output_cb(struct cryptop *crp);
   91 
   92 /*
   93  * NB: this is public for use by the PF_KEY support.
   94  * NB: if you add support here; be sure to add code to esp_attach below!
   95  */
   96 struct enc_xform *
   97 esp_algorithm_lookup(int alg)
   98 {
   99         if (alg >= ESP_ALG_MAX)
  100                 return NULL;
  101         switch (alg) {
  102         case SADB_EALG_DESCBC:
  103                 return &enc_xform_des;
  104         case SADB_EALG_3DESCBC:
  105                 return &enc_xform_3des;
  106         case SADB_X_EALG_AES:
  107                 return &enc_xform_rijndael128;
  108         case SADB_X_EALG_BLOWFISHCBC:
  109                 return &enc_xform_blf;
  110         case SADB_X_EALG_CAST128CBC:
  111                 return &enc_xform_cast5;
  112         case SADB_X_EALG_SKIPJACK:
  113                 return &enc_xform_skipjack;
  114         case SADB_EALG_NULL:
  115                 return &enc_xform_null;
  116         }
  117         return NULL;
  118 }
  119 
  120 size_t
  121 esp_hdrsiz(struct secasvar *sav)
  122 {
  123         size_t size;
  124 
  125         if (sav != NULL) {
  126                 /*XXX not right for null algorithm--does it matter??*/
  127                 IPSEC_ASSERT(sav->tdb_encalgxform != NULL,
  128                         ("SA with null xform"));
  129                 if (sav->flags & SADB_X_EXT_OLD)
  130                         size = sizeof (struct esp);
  131                 else
  132                         size = sizeof (struct newesp);
  133                 size += sav->tdb_encalgxform->blocksize + 9;
  134                 /*XXX need alg check???*/
  135                 if (sav->tdb_authalgxform != NULL && sav->replay)
  136                         size += ah_hdrsiz(sav);
  137         } else {
  138                 /*
  139                  *   base header size
  140                  * + max iv length for CBC mode
  141                  * + max pad length
  142                  * + sizeof (pad length field)
  143                  * + sizeof (next header field)
  144                  * + max icv supported.
  145                  */
  146                 size = sizeof (struct newesp) + esp_max_ivlen + 9 + 16;
  147         }
  148         return size;
  149 }
  150 
  151 /*
  152  * esp_init() is called when an SPI is being set up.
  153  */
  154 static int
  155 esp_init(struct secasvar *sav, struct xformsw *xsp)
  156 {
  157         struct enc_xform *txform;
  158         struct cryptoini cria, crie;
  159         int keylen;
  160         int error;
  161 
  162         txform = esp_algorithm_lookup(sav->alg_enc);
  163         if (txform == NULL) {
  164                 DPRINTF(("%s: unsupported encryption algorithm %d\n",
  165                         __func__, sav->alg_enc));
  166                 return EINVAL;
  167         }
  168         if (sav->key_enc == NULL) {
  169                 DPRINTF(("%s: no encoding key for %s algorithm\n",
  170                          __func__, txform->name));
  171                 return EINVAL;
  172         }
  173         if ((sav->flags&(SADB_X_EXT_OLD|SADB_X_EXT_IV4B)) == SADB_X_EXT_IV4B) {
  174                 DPRINTF(("%s: 4-byte IV not supported with protocol\n",
  175                         __func__));
  176                 return EINVAL;
  177         }
  178         keylen = _KEYLEN(sav->key_enc);
  179         if (txform->minkey > keylen || keylen > txform->maxkey) {
  180                 DPRINTF(("%s: invalid key length %u, must be in the range "
  181                         "[%u..%u] for algorithm %s\n", __func__,
  182                         keylen, txform->minkey, txform->maxkey,
  183                         txform->name));
  184                 return EINVAL;
  185         }
  186 
  187         /*
  188          * NB: The null xform needs a non-zero blocksize to keep the
  189          *      crypto code happy but if we use it to set ivlen then
  190          *      the ESP header will be processed incorrectly.  The
  191          *      compromise is to force it to zero here.
  192          */
  193         sav->ivlen = (txform == &enc_xform_null ? 0 : txform->blocksize);
  194         sav->iv = (caddr_t) malloc(sav->ivlen, M_XDATA, M_WAITOK);
  195         if (sav->iv == NULL) {
  196                 DPRINTF(("%s: no memory for IV\n", __func__));
  197                 return EINVAL;
  198         }
  199         key_randomfill(sav->iv, sav->ivlen);    /*XXX*/
  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         /* Initialize crypto session. */
  215         bzero(&crie, sizeof (crie));
  216         crie.cri_alg = sav->tdb_encalgxform->type;
  217         crie.cri_klen = _KEYBITS(sav->key_enc);
  218         crie.cri_key = _KEYBUF(sav->key_enc);
  219         /* XXX Rounds ? */
  220 
  221         if (sav->tdb_authalgxform && sav->tdb_encalgxform) {
  222                 /* init both auth & enc */
  223                 crie.cri_next = &cria;
  224                 error = crypto_newsession(&sav->tdb_cryptoid,
  225                                           &crie, crypto_support);
  226         } else if (sav->tdb_encalgxform) {
  227                 error = crypto_newsession(&sav->tdb_cryptoid,
  228                                           &crie, crypto_support);
  229         } else if (sav->tdb_authalgxform) {
  230                 error = crypto_newsession(&sav->tdb_cryptoid,
  231                                           &cria, crypto_support);
  232         } else {
  233                 /* XXX cannot happen? */
  234                 DPRINTF(("%s: no encoding OR authentication xform!\n",
  235                         __func__));
  236                 error = EINVAL;
  237         }
  238         return error;
  239 }
  240 
  241 /*
  242  * Paranoia.
  243  */
  244 static int
  245 esp_zeroize(struct secasvar *sav)
  246 {
  247         /* NB: ah_zerorize free's the crypto session state */
  248         int error = ah_zeroize(sav);
  249 
  250         if (sav->key_enc)
  251                 bzero(_KEYBUF(sav->key_enc), _KEYLEN(sav->key_enc));
  252         if (sav->iv) {
  253                 free(sav->iv, M_XDATA);
  254                 sav->iv = NULL;
  255         }
  256         sav->tdb_encalgxform = NULL;
  257         sav->tdb_xform = NULL;
  258         return error;
  259 }
  260 
  261 /*
  262  * ESP input processing, called (eventually) through the protocol switch.
  263  */
  264 static int
  265 esp_input(struct mbuf *m, struct secasvar *sav, int skip, int protoff)
  266 {
  267         struct auth_hash *esph;
  268         struct enc_xform *espx;
  269         struct tdb_ident *tdbi;
  270         struct tdb_crypto *tc;
  271         int plen, alen, hlen;
  272         struct m_tag *mtag;
  273         struct newesp *esp;
  274 
  275         struct cryptodesc *crde;
  276         struct cryptop *crp;
  277 
  278         IPSEC_SPLASSERT_SOFTNET(__func__);
  279 
  280         IPSEC_ASSERT(sav != NULL, ("null SA"));
  281         IPSEC_ASSERT(sav->tdb_encalgxform != NULL, ("null encoding xform"));
  282         IPSEC_ASSERT((skip&3) == 0 && (m->m_pkthdr.len&3) == 0,
  283                 ("misaligned packet, skip %u pkt len %u",
  284                         skip, m->m_pkthdr.len));
  285 
  286         /* XXX don't pullup, just copy header */
  287         IP6_EXTHDR_GET(esp, struct newesp *, m, skip, sizeof (struct newesp));
  288 
  289         esph = sav->tdb_authalgxform;
  290         espx = sav->tdb_encalgxform;
  291 
  292         /* Determine the ESP header length */
  293         if (sav->flags & SADB_X_EXT_OLD)
  294                 hlen = sizeof (struct esp) + sav->ivlen;
  295         else
  296                 hlen = sizeof (struct newesp) + sav->ivlen;
  297         /* Authenticator hash size */
  298         alen = esph ? AH_HMAC_HASHLEN : 0;
  299 
  300         /*
  301          * Verify payload length is multiple of encryption algorithm
  302          * block size.
  303          *
  304          * NB: This works for the null algorithm because the blocksize
  305          *     is 4 and all packets must be 4-byte aligned regardless
  306          *     of the algorithm.
  307          */
  308         plen = m->m_pkthdr.len - (skip + hlen + alen);
  309         if ((plen & (espx->blocksize - 1)) || (plen <= 0)) {
  310                 DPRINTF(("%s: payload of %d octets not a multiple of %d octets,"
  311                     "  SA %s/%08lx\n", __func__,
  312                     plen, espx->blocksize,
  313                     ipsec_address(&sav->sah->saidx.dst),
  314                     (u_long) ntohl(sav->spi)));
  315                 espstat.esps_badilen++;
  316                 m_freem(m);
  317                 return EINVAL;
  318         }
  319 
  320         /*
  321          * Check sequence number.
  322          */
  323         if (esph && sav->replay && !ipsec_chkreplay(ntohl(esp->esp_seq), sav)) {
  324                 DPRINTF(("%s: packet replay check for %s\n", __func__,
  325                     ipsec_logsastr(sav)));      /*XXX*/
  326                 espstat.esps_replay++;
  327                 m_freem(m);
  328                 return ENOBUFS;         /*XXX*/
  329         }
  330 
  331         /* Update the counters */
  332         espstat.esps_ibytes += m->m_pkthdr.len - skip - hlen - alen;
  333 
  334         /* Find out if we've already done crypto */
  335         for (mtag = m_tag_find(m, PACKET_TAG_IPSEC_IN_CRYPTO_DONE, NULL);
  336              mtag != NULL;
  337              mtag = m_tag_find(m, PACKET_TAG_IPSEC_IN_CRYPTO_DONE, mtag)) {
  338                 tdbi = (struct tdb_ident *) (mtag + 1);
  339                 if (tdbi->proto == sav->sah->saidx.proto &&
  340                     tdbi->spi == sav->spi &&
  341                     !bcmp(&tdbi->dst, &sav->sah->saidx.dst,
  342                           sizeof(union sockaddr_union)))
  343                         break;
  344         }
  345 
  346         /* Get crypto descriptors */
  347         crp = crypto_getreq(esph && espx ? 2 : 1);
  348         if (crp == NULL) {
  349                 DPRINTF(("%s: failed to acquire crypto descriptors\n",
  350                         __func__));
  351                 espstat.esps_crypto++;
  352                 m_freem(m);
  353                 return ENOBUFS;
  354         }
  355 
  356         /* Get IPsec-specific opaque pointer */
  357         if (esph == NULL || mtag != NULL)
  358                 tc = (struct tdb_crypto *) malloc(sizeof(struct tdb_crypto),
  359                     M_XDATA, M_NOWAIT|M_ZERO);
  360         else
  361                 tc = (struct tdb_crypto *) malloc(sizeof(struct tdb_crypto) + alen,
  362                     M_XDATA, M_NOWAIT|M_ZERO);
  363         if (tc == NULL) {
  364                 crypto_freereq(crp);
  365                 DPRINTF(("%s: failed to allocate tdb_crypto\n", __func__));
  366                 espstat.esps_crypto++;
  367                 m_freem(m);
  368                 return ENOBUFS;
  369         }
  370 
  371         tc->tc_ptr = (caddr_t) mtag;
  372 
  373         if (esph) {
  374                 struct cryptodesc *crda = crp->crp_desc;
  375 
  376                 IPSEC_ASSERT(crda != NULL, ("null ah crypto descriptor"));
  377 
  378                 /* Authentication descriptor */
  379                 crda->crd_skip = skip;
  380                 crda->crd_len = m->m_pkthdr.len - (skip + alen);
  381                 crda->crd_inject = m->m_pkthdr.len - alen;
  382 
  383                 crda->crd_alg = esph->type;
  384                 crda->crd_key = _KEYBUF(sav->key_auth);
  385                 crda->crd_klen = _KEYBITS(sav->key_auth);
  386 
  387                 /* Copy the authenticator */
  388                 if (mtag == NULL)
  389                         m_copydata(m, m->m_pkthdr.len - alen, alen,
  390                                    (caddr_t) (tc + 1));
  391 
  392                 /* Chain authentication request */
  393                 crde = crda->crd_next;
  394         } else {
  395                 crde = crp->crp_desc;
  396         }
  397 
  398         /* Crypto operation descriptor */
  399         crp->crp_ilen = m->m_pkthdr.len; /* Total input length */
  400         crp->crp_flags = CRYPTO_F_IMBUF | CRYPTO_F_CBIFSYNC;
  401         crp->crp_buf = (caddr_t) m;
  402         crp->crp_callback = esp_input_cb;
  403         crp->crp_sid = sav->tdb_cryptoid;
  404         crp->crp_opaque = (caddr_t) tc;
  405 
  406         /* These are passed as-is to the callback */
  407         tc->tc_spi = sav->spi;
  408         tc->tc_dst = sav->sah->saidx.dst;
  409         tc->tc_proto = sav->sah->saidx.proto;
  410         tc->tc_protoff = protoff;
  411         tc->tc_skip = skip;
  412 
  413         /* Decryption descriptor */
  414         if (espx) {
  415                 IPSEC_ASSERT(crde != NULL, ("null esp crypto descriptor"));
  416                 crde->crd_skip = skip + hlen;
  417                 crde->crd_len = m->m_pkthdr.len - (skip + hlen + alen);
  418                 crde->crd_inject = skip + hlen - sav->ivlen;
  419 
  420                 crde->crd_alg = espx->type;
  421                 crde->crd_key = _KEYBUF(sav->key_enc);
  422                 crde->crd_klen = _KEYBITS(sav->key_enc);
  423                 /* XXX Rounds ? */
  424         }
  425 
  426         if (mtag == NULL)
  427                 return crypto_dispatch(crp);
  428         else
  429                 return esp_input_cb(crp);
  430 }
  431 
  432 #ifdef INET6
  433 #define IPSEC_COMMON_INPUT_CB(m, sav, skip, protoff, mtag) do {              \
  434         if (saidx->dst.sa.sa_family == AF_INET6) {                           \
  435                 error = ipsec6_common_input_cb(m, sav, skip, protoff, mtag); \
  436         } else {                                                             \
  437                 error = ipsec4_common_input_cb(m, sav, skip, protoff, mtag); \
  438         }                                                                    \
  439 } while (0)
  440 #else
  441 #define IPSEC_COMMON_INPUT_CB(m, sav, skip, protoff, mtag)                   \
  442         (error = ipsec4_common_input_cb(m, sav, skip, protoff, mtag))
  443 #endif
  444 
  445 /*
  446  * ESP input callback from the crypto driver.
  447  */
  448 static int
  449 esp_input_cb(struct cryptop *crp)
  450 {
  451         u_int8_t lastthree[3], aalg[AH_HMAC_HASHLEN];
  452         int hlen, skip, protoff, error;
  453         struct mbuf *m;
  454         struct cryptodesc *crd;
  455         struct auth_hash *esph;
  456         struct enc_xform *espx;
  457         struct tdb_crypto *tc;
  458         struct m_tag *mtag;
  459         struct secasvar *sav;
  460         struct secasindex *saidx;
  461         caddr_t ptr;
  462 
  463         crd = crp->crp_desc;
  464         IPSEC_ASSERT(crd != NULL, ("null crypto descriptor!"));
  465 
  466         tc = (struct tdb_crypto *) crp->crp_opaque;
  467         IPSEC_ASSERT(tc != NULL, ("null opaque crypto data area!"));
  468         skip = tc->tc_skip;
  469         protoff = tc->tc_protoff;
  470         mtag = (struct m_tag *) tc->tc_ptr;
  471         m = (struct mbuf *) crp->crp_buf;
  472 
  473         sav = KEY_ALLOCSA(&tc->tc_dst, tc->tc_proto, tc->tc_spi);
  474         if (sav == NULL) {
  475                 espstat.esps_notdb++;
  476                 DPRINTF(("%s: SA gone during crypto (SA %s/%08lx proto %u)\n",
  477                     __func__, ipsec_address(&tc->tc_dst),
  478                     (u_long) ntohl(tc->tc_spi), tc->tc_proto));
  479                 error = ENOBUFS;                /*XXX*/
  480                 goto bad;
  481         }
  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                         KEY_FREESAV(&sav);
  499                         return crypto_dispatch(crp);
  500                 }
  501 
  502                 espstat.esps_noxform++;
  503                 DPRINTF(("%s: crypto error %d\n", __func__, crp->crp_etype));
  504                 error = crp->crp_etype;
  505                 goto bad;
  506         }
  507 
  508         /* Shouldn't happen... */
  509         if (m == NULL) {
  510                 espstat.esps_crypto++;
  511                 DPRINTF(("%s: bogus returned buffer from crypto\n", __func__));
  512                 error = EINVAL;
  513                 goto bad;
  514         }
  515         espstat.esps_hist[sav->alg_enc]++;
  516 
  517         /* If authentication was performed, check now. */
  518         if (esph != NULL) {
  519                 /*
  520                  * If we have a tag, it means an IPsec-aware NIC did
  521                  * the verification for us.  Otherwise we need to
  522                  * check the authentication calculation.
  523                  */
  524                 ahstat.ahs_hist[sav->alg_auth]++;
  525                 if (mtag == NULL) {
  526                         /* Copy the authenticator from the packet */
  527                         m_copydata(m, m->m_pkthdr.len - esph->authsize,
  528                                 esph->authsize, aalg);
  529 
  530                         ptr = (caddr_t) (tc + 1);
  531 
  532                         /* Verify authenticator */
  533                         if (bcmp(ptr, aalg, esph->authsize) != 0) {
  534                                 DPRINTF(("%s: "
  535                     "authentication hash mismatch for packet in SA %s/%08lx\n",
  536                                     __func__,
  537                                     ipsec_address(&saidx->dst),
  538                                     (u_long) ntohl(sav->spi)));
  539                                 espstat.esps_badauth++;
  540                                 error = EACCES;
  541                                 goto bad;
  542                         }
  543                 }
  544 
  545                 /* Remove trailing authenticator */
  546                 m_adj(m, -(esph->authsize));
  547         }
  548 
  549         /* Release the crypto descriptors */
  550         free(tc, M_XDATA), tc = NULL;
  551         crypto_freereq(crp), crp = NULL;
  552 
  553         /*
  554          * Packet is now decrypted.
  555          */
  556         m->m_flags |= M_DECRYPTED;
  557 
  558         /* Determine the ESP header length */
  559         if (sav->flags & SADB_X_EXT_OLD)
  560                 hlen = sizeof (struct esp) + sav->ivlen;
  561         else
  562                 hlen = sizeof (struct newesp) + sav->ivlen;
  563 
  564         /* Remove the ESP header and IV from the mbuf. */
  565         error = m_striphdr(m, skip, hlen);
  566         if (error) {
  567                 espstat.esps_hdrops++;
  568                 DPRINTF(("%s: bad mbuf chain, SA %s/%08lx\n", __func__,
  569                     ipsec_address(&sav->sah->saidx.dst),
  570                     (u_long) ntohl(sav->spi)));
  571                 goto bad;
  572         }
  573 
  574         /* Save the last three bytes of decrypted data */
  575         m_copydata(m, m->m_pkthdr.len - 3, 3, lastthree);
  576 
  577         /* Verify pad length */
  578         if (lastthree[1] + 2 > m->m_pkthdr.len - skip) {
  579                 espstat.esps_badilen++;
  580                 DPRINTF(("%s: invalid padding length %d for %u byte packet "
  581                         "in SA %s/%08lx\n", __func__,
  582                          lastthree[1], m->m_pkthdr.len - skip,
  583                          ipsec_address(&sav->sah->saidx.dst),
  584                          (u_long) ntohl(sav->spi)));
  585                 error = EINVAL;
  586                 goto bad;
  587         }
  588 
  589         /* Verify correct decryption by checking the last padding bytes */
  590         if ((sav->flags & SADB_X_EXT_PMASK) != SADB_X_EXT_PRAND) {
  591                 if (lastthree[1] != lastthree[0] && lastthree[1] != 0) {
  592                         espstat.esps_badenc++;
  593                         DPRINTF(("%s: decryption failed for packet in "
  594                                 "SA %s/%08lx\n", __func__,
  595                                 ipsec_address(&sav->sah->saidx.dst),
  596                                 (u_long) ntohl(sav->spi)));
  597                         error = EINVAL;
  598                         goto bad;
  599                 }
  600         }
  601 
  602         /* Trim the mbuf chain to remove trailing authenticator and padding */
  603         m_adj(m, -(lastthree[1] + 2));
  604 
  605         /* Restore the Next Protocol field */
  606         m_copyback(m, protoff, sizeof (u_int8_t), lastthree + 2);
  607 
  608         IPSEC_COMMON_INPUT_CB(m, sav, skip, protoff, mtag);
  609 
  610         KEY_FREESAV(&sav);
  611         return error;
  612 bad:
  613         if (sav)
  614                 KEY_FREESAV(&sav);
  615         if (m != NULL)
  616                 m_freem(m);
  617         if (tc != NULL)
  618                 free(tc, M_XDATA);
  619         if (crp != NULL)
  620                 crypto_freereq(crp);
  621         return error;
  622 }
  623 
  624 /*
  625  * ESP output routine, called by ipsec[46]_process_packet().
  626  */
  627 static int
  628 esp_output(
  629         struct mbuf *m,
  630         struct ipsecrequest *isr,
  631         struct mbuf **mp,
  632         int skip,
  633         int protoff
  634 )
  635 {
  636         struct enc_xform *espx;
  637         struct auth_hash *esph;
  638         int hlen, rlen, plen, padding, blks, alen, i, roff;
  639         struct mbuf *mo = (struct mbuf *) NULL;
  640         struct tdb_crypto *tc;
  641         struct secasvar *sav;
  642         struct secasindex *saidx;
  643         unsigned char *pad;
  644         u_int8_t prot;
  645         int error, maxpacketsize;
  646 
  647         struct cryptodesc *crde = NULL, *crda = NULL;
  648         struct cryptop *crp;
  649 
  650         IPSEC_SPLASSERT_SOFTNET(__func__);
  651 
  652         sav = isr->sav;
  653         IPSEC_ASSERT(sav != NULL, ("null SA"));
  654         esph = sav->tdb_authalgxform;
  655         espx = sav->tdb_encalgxform;
  656         IPSEC_ASSERT(espx != NULL, ("null encoding xform"));
  657 
  658         if (sav->flags & SADB_X_EXT_OLD)
  659                 hlen = sizeof (struct esp) + sav->ivlen;
  660         else
  661                 hlen = sizeof (struct newesp) + sav->ivlen;
  662 
  663         rlen = m->m_pkthdr.len - skip;  /* Raw payload length. */
  664         /*
  665          * NB: The null encoding transform has a blocksize of 4
  666          *     so that headers are properly aligned.
  667          */
  668         blks = espx->blocksize;         /* IV blocksize */
  669 
  670         /* XXX clamp padding length a la KAME??? */
  671         padding = ((blks - ((rlen + 2) % blks)) % blks) + 2;
  672         plen = rlen + padding;          /* Padded payload length. */
  673 
  674         if (esph)
  675                 alen = AH_HMAC_HASHLEN;
  676         else
  677                 alen = 0;
  678 
  679         espstat.esps_output++;
  680 
  681         saidx = &sav->sah->saidx;
  682         /* Check for maximum packet size violations. */
  683         switch (saidx->dst.sa.sa_family) {
  684 #ifdef INET
  685         case AF_INET:
  686                 maxpacketsize = IP_MAXPACKET;
  687                 break;
  688 #endif /* INET */
  689 #ifdef INET6
  690         case AF_INET6:
  691                 maxpacketsize = IPV6_MAXPACKET;
  692                 break;
  693 #endif /* INET6 */
  694         default:
  695                 DPRINTF(("%s: unknown/unsupported protocol "
  696                     "family %d, SA %s/%08lx\n", __func__,
  697                     saidx->dst.sa.sa_family, ipsec_address(&saidx->dst),
  698                     (u_long) ntohl(sav->spi)));
  699                 espstat.esps_nopf++;
  700                 error = EPFNOSUPPORT;
  701                 goto bad;
  702         }
  703         if (skip + hlen + rlen + padding + alen > maxpacketsize) {
  704                 DPRINTF(("%s: packet in SA %s/%08lx got too big "
  705                     "(len %u, max len %u)\n", __func__,
  706                     ipsec_address(&saidx->dst), (u_long) ntohl(sav->spi),
  707                     skip + hlen + rlen + padding + alen, maxpacketsize));
  708                 espstat.esps_toobig++;
  709                 error = EMSGSIZE;
  710                 goto bad;
  711         }
  712 
  713         /* Update the counters. */
  714         espstat.esps_obytes += m->m_pkthdr.len - skip;
  715 
  716         m = m_clone(m);
  717         if (m == NULL) {
  718                 DPRINTF(("%s: cannot clone mbuf chain, SA %s/%08lx\n", __func__,
  719                     ipsec_address(&saidx->dst), (u_long) ntohl(sav->spi)));
  720                 espstat.esps_hdrops++;
  721                 error = ENOBUFS;
  722                 goto bad;
  723         }
  724 
  725         /* Inject ESP header. */
  726         mo = m_makespace(m, skip, hlen, &roff);
  727         if (mo == NULL) {
  728                 DPRINTF(("%s: %u byte ESP hdr inject failed for SA %s/%08lx\n",
  729                     __func__, hlen, ipsec_address(&saidx->dst),
  730                     (u_long) ntohl(sav->spi)));
  731                 espstat.esps_hdrops++;          /* XXX diffs from openbsd */
  732                 error = ENOBUFS;
  733                 goto bad;
  734         }
  735 
  736         /* Initialize ESP header. */
  737         bcopy((caddr_t) &sav->spi, mtod(mo, caddr_t) + roff, sizeof(u_int32_t));
  738         if (sav->replay) {
  739                 u_int32_t replay = htonl(++(sav->replay->count));
  740                 bcopy((caddr_t) &replay,
  741                     mtod(mo, caddr_t) + roff + sizeof(u_int32_t),
  742                     sizeof(u_int32_t));
  743         }
  744 
  745         /*
  746          * Add padding -- better to do it ourselves than use the crypto engine,
  747          * although if/when we support compression, we'd have to do that.
  748          */
  749         pad = (u_char *) m_pad(m, padding + alen);
  750         if (pad == NULL) {
  751                 DPRINTF(("%s: m_pad failed for SA %s/%08lx\n", __func__,
  752                     ipsec_address(&saidx->dst), (u_long) ntohl(sav->spi)));
  753                 m = NULL;               /* NB: free'd by m_pad */
  754                 error = ENOBUFS;
  755                 goto bad;
  756         }
  757 
  758         /*
  759          * Add padding: random, zero, or self-describing.
  760          * XXX catch unexpected setting
  761          */
  762         switch (sav->flags & SADB_X_EXT_PMASK) {
  763         case SADB_X_EXT_PRAND:
  764                 (void) read_random(pad, padding - 2);
  765                 break;
  766         case SADB_X_EXT_PZERO:
  767                 bzero(pad, padding - 2);
  768                 break;
  769         case SADB_X_EXT_PSEQ:
  770                 for (i = 0; i < padding - 2; i++)
  771                         pad[i] = i+1;
  772                 break;
  773         }
  774 
  775         /* Fix padding length and Next Protocol in padding itself. */
  776         pad[padding - 2] = padding - 2;
  777         m_copydata(m, protoff, sizeof(u_int8_t), pad + padding - 1);
  778 
  779         /* Fix Next Protocol in IPv4/IPv6 header. */
  780         prot = IPPROTO_ESP;
  781         m_copyback(m, protoff, sizeof(u_int8_t), (u_char *) &prot);
  782 
  783         /* Get crypto descriptors. */
  784         crp = crypto_getreq(esph && espx ? 2 : 1);
  785         if (crp == NULL) {
  786                 DPRINTF(("%s: failed to acquire crypto descriptors\n",
  787                         __func__));
  788                 espstat.esps_crypto++;
  789                 error = ENOBUFS;
  790                 goto bad;
  791         }
  792 
  793         if (espx) {
  794                 crde = crp->crp_desc;
  795                 crda = crde->crd_next;
  796 
  797                 /* Encryption descriptor. */
  798                 crde->crd_skip = skip + hlen;
  799                 crde->crd_len = m->m_pkthdr.len - (skip + hlen + alen);
  800                 crde->crd_flags = CRD_F_ENCRYPT;
  801                 crde->crd_inject = skip + hlen - sav->ivlen;
  802 
  803                 /* Encryption operation. */
  804                 crde->crd_alg = espx->type;
  805                 crde->crd_key = _KEYBUF(sav->key_enc);
  806                 crde->crd_klen = _KEYBITS(sav->key_enc);
  807                 /* XXX Rounds ? */
  808         } else
  809                 crda = crp->crp_desc;
  810 
  811         /* IPsec-specific opaque crypto info. */
  812         tc = (struct tdb_crypto *) malloc(sizeof(struct tdb_crypto),
  813                 M_XDATA, M_NOWAIT|M_ZERO);
  814         if (tc == NULL) {
  815                 crypto_freereq(crp);
  816                 DPRINTF(("%s: failed to allocate tdb_crypto\n", __func__));
  817                 espstat.esps_crypto++;
  818                 error = ENOBUFS;
  819                 goto bad;
  820         }
  821 
  822         /* Callback parameters */
  823         tc->tc_isr = isr;
  824         tc->tc_spi = sav->spi;
  825         tc->tc_dst = saidx->dst;
  826         tc->tc_proto = saidx->proto;
  827 
  828         /* Crypto operation descriptor. */
  829         crp->crp_ilen = m->m_pkthdr.len; /* Total input length. */
  830         crp->crp_flags = CRYPTO_F_IMBUF | CRYPTO_F_CBIFSYNC;
  831         crp->crp_buf = (caddr_t) m;
  832         crp->crp_callback = esp_output_cb;
  833         crp->crp_opaque = (caddr_t) tc;
  834         crp->crp_sid = sav->tdb_cryptoid;
  835 
  836         if (esph) {
  837                 /* Authentication descriptor. */
  838                 crda->crd_skip = skip;
  839                 crda->crd_len = m->m_pkthdr.len - (skip + alen);
  840                 crda->crd_inject = m->m_pkthdr.len - alen;
  841 
  842                 /* Authentication operation. */
  843                 crda->crd_alg = esph->type;
  844                 crda->crd_key = _KEYBUF(sav->key_auth);
  845                 crda->crd_klen = _KEYBITS(sav->key_auth);
  846         }
  847 
  848         return crypto_dispatch(crp);
  849 bad:
  850         if (m)
  851                 m_freem(m);
  852         return (error);
  853 }
  854 
  855 /*
  856  * ESP output callback from the crypto driver.
  857  */
  858 static int
  859 esp_output_cb(struct cryptop *crp)
  860 {
  861         struct tdb_crypto *tc;
  862         struct ipsecrequest *isr;
  863         struct secasvar *sav;
  864         struct mbuf *m;
  865         int err, error;
  866 
  867         tc = (struct tdb_crypto *) crp->crp_opaque;
  868         IPSEC_ASSERT(tc != NULL, ("null opaque data area!"));
  869         m = (struct mbuf *) crp->crp_buf;
  870 
  871         isr = tc->tc_isr;
  872         IPSECREQUEST_LOCK(isr);
  873         sav = KEY_ALLOCSA(&tc->tc_dst, tc->tc_proto, tc->tc_spi);
  874         if (sav == NULL) {
  875                 espstat.esps_notdb++;
  876                 DPRINTF(("%s: SA gone during crypto (SA %s/%08lx proto %u)\n",
  877                     __func__, ipsec_address(&tc->tc_dst),
  878                     (u_long) ntohl(tc->tc_spi), tc->tc_proto));
  879                 error = ENOBUFS;                /*XXX*/
  880                 goto bad;
  881         }
  882         IPSEC_ASSERT(isr->sav == sav,
  883                 ("SA changed was %p now %p\n", isr->sav, sav));
  884 
  885         /* Check for crypto errors. */
  886         if (crp->crp_etype) {
  887                 /* Reset session ID. */
  888                 if (sav->tdb_cryptoid != 0)
  889                         sav->tdb_cryptoid = crp->crp_sid;
  890 
  891                 if (crp->crp_etype == EAGAIN) {
  892                         KEY_FREESAV(&sav);
  893                         IPSECREQUEST_UNLOCK(isr);
  894                         return crypto_dispatch(crp);
  895                 }
  896 
  897                 espstat.esps_noxform++;
  898                 DPRINTF(("%s: crypto error %d\n", __func__, crp->crp_etype));
  899                 error = crp->crp_etype;
  900                 goto bad;
  901         }
  902 
  903         /* Shouldn't happen... */
  904         if (m == NULL) {
  905                 espstat.esps_crypto++;
  906                 DPRINTF(("%s: bogus returned buffer from crypto\n", __func__));
  907                 error = EINVAL;
  908                 goto bad;
  909         }
  910         espstat.esps_hist[sav->alg_enc]++;
  911         if (sav->tdb_authalgxform != NULL)
  912                 ahstat.ahs_hist[sav->alg_auth]++;
  913 
  914         /* Release crypto descriptors. */
  915         free(tc, M_XDATA);
  916         crypto_freereq(crp);
  917 
  918         /* NB: m is reclaimed by ipsec_process_done. */
  919         err = ipsec_process_done(m, isr);
  920         KEY_FREESAV(&sav);
  921         IPSECREQUEST_UNLOCK(isr);
  922 
  923         return err;
  924 bad:
  925         if (sav)
  926                 KEY_FREESAV(&sav);
  927         IPSECREQUEST_UNLOCK(isr);
  928         if (m)
  929                 m_freem(m);
  930         free(tc, M_XDATA);
  931         crypto_freereq(crp);
  932         return error;
  933 }
  934 
  935 static struct xformsw esp_xformsw = {
  936         XF_ESP,         XFT_CONF|XFT_AUTH,      "IPsec ESP",
  937         esp_init,       esp_zeroize,            esp_input,
  938         esp_output
  939 };
  940 
  941 static void
  942 esp_attach(void)
  943 {
  944 #define MAXIV(xform)                                    \
  945         if (xform.blocksize > esp_max_ivlen)            \
  946                 esp_max_ivlen = xform.blocksize         \
  947 
  948         esp_max_ivlen = 0;
  949         MAXIV(enc_xform_des);           /* SADB_EALG_DESCBC */
  950         MAXIV(enc_xform_3des);          /* SADB_EALG_3DESCBC */
  951         MAXIV(enc_xform_rijndael128);   /* SADB_X_EALG_AES */
  952         MAXIV(enc_xform_blf);           /* SADB_X_EALG_BLOWFISHCBC */
  953         MAXIV(enc_xform_cast5);         /* SADB_X_EALG_CAST128CBC */
  954         MAXIV(enc_xform_skipjack);      /* SADB_X_EALG_SKIPJACK */
  955         MAXIV(enc_xform_null);          /* SADB_EALG_NULL */
  956 
  957         xform_register(&esp_xformsw);
  958 #undef MAXIV
  959 }
  960 SYSINIT(esp_xform_init, SI_SUB_DRIVERS, SI_ORDER_FIRST, esp_attach, NULL)

Cache object: 9a4273bc0ae2c54c975300787e05a01e


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