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/6.2/sys/netipsec/xform_esp.c 161999 2006-09-04 15:17:50Z pjd $ */
    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         NET_LOCK_GIANT();
  464 
  465         crd = crp->crp_desc;
  466         IPSEC_ASSERT(crd != NULL, ("null crypto descriptor!"));
  467 
  468         tc = (struct tdb_crypto *) crp->crp_opaque;
  469         IPSEC_ASSERT(tc != NULL, ("null opaque crypto data area!"));
  470         skip = tc->tc_skip;
  471         protoff = tc->tc_protoff;
  472         mtag = (struct m_tag *) tc->tc_ptr;
  473         m = (struct mbuf *) crp->crp_buf;
  474 
  475         sav = KEY_ALLOCSA(&tc->tc_dst, tc->tc_proto, tc->tc_spi);
  476         if (sav == NULL) {
  477                 espstat.esps_notdb++;
  478                 DPRINTF(("%s: SA gone during crypto (SA %s/%08lx proto %u)\n",
  479                     __func__, ipsec_address(&tc->tc_dst),
  480                     (u_long) ntohl(tc->tc_spi), tc->tc_proto));
  481                 error = ENOBUFS;                /*XXX*/
  482                 goto bad;
  483         }
  484 
  485         saidx = &sav->sah->saidx;
  486         IPSEC_ASSERT(saidx->dst.sa.sa_family == AF_INET ||
  487                 saidx->dst.sa.sa_family == AF_INET6,
  488                 ("unexpected protocol family %u", saidx->dst.sa.sa_family));
  489 
  490         esph = sav->tdb_authalgxform;
  491         espx = sav->tdb_encalgxform;
  492 
  493         /* Check for crypto errors */
  494         if (crp->crp_etype) {
  495                 /* Reset the session ID */
  496                 if (sav->tdb_cryptoid != 0)
  497                         sav->tdb_cryptoid = crp->crp_sid;
  498 
  499                 if (crp->crp_etype == EAGAIN) {
  500                         KEY_FREESAV(&sav);
  501                         error = crypto_dispatch(crp);
  502                         NET_UNLOCK_GIANT();
  503                         return error;
  504                 }
  505 
  506                 espstat.esps_noxform++;
  507                 DPRINTF(("%s: crypto error %d\n", __func__, crp->crp_etype));
  508                 error = crp->crp_etype;
  509                 goto bad;
  510         }
  511 
  512         /* Shouldn't happen... */
  513         if (m == NULL) {
  514                 espstat.esps_crypto++;
  515                 DPRINTF(("%s: bogus returned buffer from crypto\n", __func__));
  516                 error = EINVAL;
  517                 goto bad;
  518         }
  519         espstat.esps_hist[sav->alg_enc]++;
  520 
  521         /* If authentication was performed, check now. */
  522         if (esph != NULL) {
  523                 /*
  524                  * If we have a tag, it means an IPsec-aware NIC did
  525                  * the verification for us.  Otherwise we need to
  526                  * check the authentication calculation.
  527                  */
  528                 ahstat.ahs_hist[sav->alg_auth]++;
  529                 if (mtag == NULL) {
  530                         /* Copy the authenticator from the packet */
  531                         m_copydata(m, m->m_pkthdr.len - AH_HMAC_HASHLEN,
  532                                 AH_HMAC_HASHLEN, aalg);
  533 
  534                         ptr = (caddr_t) (tc + 1);
  535 
  536                         /* Verify authenticator */
  537                         if (bcmp(ptr, aalg, AH_HMAC_HASHLEN) != 0) {
  538                                 DPRINTF(("%s: "
  539                     "authentication hash mismatch for packet in SA %s/%08lx\n",
  540                                     __func__,
  541                                     ipsec_address(&saidx->dst),
  542                                     (u_long) ntohl(sav->spi)));
  543                                 espstat.esps_badauth++;
  544                                 error = EACCES;
  545                                 goto bad;
  546                         }
  547                 }
  548 
  549                 /* Remove trailing authenticator */
  550                 m_adj(m, -AH_HMAC_HASHLEN);
  551         }
  552 
  553         /* Release the crypto descriptors */
  554         free(tc, M_XDATA), tc = NULL;
  555         crypto_freereq(crp), crp = NULL;
  556 
  557         /*
  558          * Packet is now decrypted.
  559          */
  560         m->m_flags |= M_DECRYPTED;
  561 
  562         /*
  563          * Update replay sequence number, if appropriate.
  564          */
  565         if (sav->replay) {
  566                 u_int32_t seq;
  567 
  568                 m_copydata(m, skip + offsetof(struct newesp, esp_seq),
  569                            sizeof (seq), (caddr_t) &seq);
  570                 if (ipsec_updatereplay(ntohl(seq), sav)) {
  571                         DPRINTF(("%s: packet replay check for %s\n", __func__,
  572                             ipsec_logsastr(sav)));
  573                         espstat.esps_replay++;
  574                         error = ENOBUFS;
  575                         goto bad;
  576                 }
  577         }
  578 
  579         /* Determine the ESP header length */
  580         if (sav->flags & SADB_X_EXT_OLD)
  581                 hlen = sizeof (struct esp) + sav->ivlen;
  582         else
  583                 hlen = sizeof (struct newesp) + sav->ivlen;
  584 
  585         /* Remove the ESP header and IV from the mbuf. */
  586         error = m_striphdr(m, skip, hlen);
  587         if (error) {
  588                 espstat.esps_hdrops++;
  589                 DPRINTF(("%s: bad mbuf chain, SA %s/%08lx\n", __func__,
  590                     ipsec_address(&sav->sah->saidx.dst),
  591                     (u_long) ntohl(sav->spi)));
  592                 goto bad;
  593         }
  594 
  595         /* Save the last three bytes of decrypted data */
  596         m_copydata(m, m->m_pkthdr.len - 3, 3, lastthree);
  597 
  598         /* Verify pad length */
  599         if (lastthree[1] + 2 > m->m_pkthdr.len - skip) {
  600                 espstat.esps_badilen++;
  601                 DPRINTF(("%s: invalid padding length %d for %u byte packet "
  602                         "in SA %s/%08lx\n", __func__,
  603                          lastthree[1], m->m_pkthdr.len - skip,
  604                          ipsec_address(&sav->sah->saidx.dst),
  605                          (u_long) ntohl(sav->spi)));
  606                 error = EINVAL;
  607                 goto bad;
  608         }
  609 
  610         /* Verify correct decryption by checking the last padding bytes */
  611         if ((sav->flags & SADB_X_EXT_PMASK) != SADB_X_EXT_PRAND) {
  612                 if (lastthree[1] != lastthree[0] && lastthree[1] != 0) {
  613                         espstat.esps_badenc++;
  614                         DPRINTF(("%s: decryption failed for packet in "
  615                                 "SA %s/%08lx\n", __func__,
  616                                 ipsec_address(&sav->sah->saidx.dst),
  617                                 (u_long) ntohl(sav->spi)));
  618                         error = EINVAL;
  619                         goto bad;
  620                 }
  621         }
  622 
  623         /* Trim the mbuf chain to remove trailing authenticator and padding */
  624         m_adj(m, -(lastthree[1] + 2));
  625 
  626         /* Restore the Next Protocol field */
  627         m_copyback(m, protoff, sizeof (u_int8_t), lastthree + 2);
  628 
  629         IPSEC_COMMON_INPUT_CB(m, sav, skip, protoff, mtag);
  630 
  631         KEY_FREESAV(&sav);
  632         NET_UNLOCK_GIANT();
  633         return error;
  634 bad:
  635         if (sav)
  636                 KEY_FREESAV(&sav);
  637         if (m != NULL)
  638                 m_freem(m);
  639         if (tc != NULL)
  640                 free(tc, M_XDATA);
  641         if (crp != NULL)
  642                 crypto_freereq(crp);
  643         NET_UNLOCK_GIANT();
  644         return error;
  645 }
  646 
  647 /*
  648  * ESP output routine, called by ipsec[46]_process_packet().
  649  */
  650 static int
  651 esp_output(
  652         struct mbuf *m,
  653         struct ipsecrequest *isr,
  654         struct mbuf **mp,
  655         int skip,
  656         int protoff
  657 )
  658 {
  659         struct enc_xform *espx;
  660         struct auth_hash *esph;
  661         int hlen, rlen, plen, padding, blks, alen, i, roff;
  662         struct mbuf *mo = (struct mbuf *) NULL;
  663         struct tdb_crypto *tc;
  664         struct secasvar *sav;
  665         struct secasindex *saidx;
  666         unsigned char *pad;
  667         u_int8_t prot;
  668         int error, maxpacketsize;
  669 
  670         struct cryptodesc *crde = NULL, *crda = NULL;
  671         struct cryptop *crp;
  672 
  673         IPSEC_SPLASSERT_SOFTNET(__func__);
  674 
  675         sav = isr->sav;
  676         IPSEC_ASSERT(sav != NULL, ("null SA"));
  677         esph = sav->tdb_authalgxform;
  678         espx = sav->tdb_encalgxform;
  679         IPSEC_ASSERT(espx != NULL, ("null encoding xform"));
  680 
  681         if (sav->flags & SADB_X_EXT_OLD)
  682                 hlen = sizeof (struct esp) + sav->ivlen;
  683         else
  684                 hlen = sizeof (struct newesp) + sav->ivlen;
  685 
  686         rlen = m->m_pkthdr.len - skip;  /* Raw payload length. */
  687         /*
  688          * NB: The null encoding transform has a blocksize of 4
  689          *     so that headers are properly aligned.
  690          */
  691         blks = espx->blocksize;         /* IV blocksize */
  692 
  693         /* XXX clamp padding length a la KAME??? */
  694         padding = ((blks - ((rlen + 2) % blks)) % blks) + 2;
  695         plen = rlen + padding;          /* Padded payload length. */
  696 
  697         if (esph)
  698                 alen = AH_HMAC_HASHLEN;
  699         else
  700                 alen = 0;
  701 
  702         espstat.esps_output++;
  703 
  704         saidx = &sav->sah->saidx;
  705         /* Check for maximum packet size violations. */
  706         switch (saidx->dst.sa.sa_family) {
  707 #ifdef INET
  708         case AF_INET:
  709                 maxpacketsize = IP_MAXPACKET;
  710                 break;
  711 #endif /* INET */
  712 #ifdef INET6
  713         case AF_INET6:
  714                 maxpacketsize = IPV6_MAXPACKET;
  715                 break;
  716 #endif /* INET6 */
  717         default:
  718                 DPRINTF(("%s: unknown/unsupported protocol "
  719                     "family %d, SA %s/%08lx\n", __func__,
  720                     saidx->dst.sa.sa_family, ipsec_address(&saidx->dst),
  721                     (u_long) ntohl(sav->spi)));
  722                 espstat.esps_nopf++;
  723                 error = EPFNOSUPPORT;
  724                 goto bad;
  725         }
  726         if (skip + hlen + rlen + padding + alen > maxpacketsize) {
  727                 DPRINTF(("%s: packet in SA %s/%08lx got too big "
  728                     "(len %u, max len %u)\n", __func__,
  729                     ipsec_address(&saidx->dst), (u_long) ntohl(sav->spi),
  730                     skip + hlen + rlen + padding + alen, maxpacketsize));
  731                 espstat.esps_toobig++;
  732                 error = EMSGSIZE;
  733                 goto bad;
  734         }
  735 
  736         /* Update the counters. */
  737         espstat.esps_obytes += m->m_pkthdr.len - skip;
  738 
  739         m = m_unshare(m, M_NOWAIT);
  740         if (m == NULL) {
  741                 DPRINTF(("%s: cannot clone mbuf chain, SA %s/%08lx\n", __func__,
  742                     ipsec_address(&saidx->dst), (u_long) ntohl(sav->spi)));
  743                 espstat.esps_hdrops++;
  744                 error = ENOBUFS;
  745                 goto bad;
  746         }
  747 
  748         /* Inject ESP header. */
  749         mo = m_makespace(m, skip, hlen, &roff);
  750         if (mo == NULL) {
  751                 DPRINTF(("%s: %u byte ESP hdr inject failed for SA %s/%08lx\n",
  752                     __func__, hlen, ipsec_address(&saidx->dst),
  753                     (u_long) ntohl(sav->spi)));
  754                 espstat.esps_hdrops++;          /* XXX diffs from openbsd */
  755                 error = ENOBUFS;
  756                 goto bad;
  757         }
  758 
  759         /* Initialize ESP header. */
  760         bcopy((caddr_t) &sav->spi, mtod(mo, caddr_t) + roff, sizeof(u_int32_t));
  761         if (sav->replay) {
  762                 u_int32_t replay = htonl(++(sav->replay->count));
  763                 bcopy((caddr_t) &replay,
  764                     mtod(mo, caddr_t) + roff + sizeof(u_int32_t),
  765                     sizeof(u_int32_t));
  766         }
  767 
  768         /*
  769          * Add padding -- better to do it ourselves than use the crypto engine,
  770          * although if/when we support compression, we'd have to do that.
  771          */
  772         pad = (u_char *) m_pad(m, padding + alen);
  773         if (pad == NULL) {
  774                 DPRINTF(("%s: m_pad failed for SA %s/%08lx\n", __func__,
  775                     ipsec_address(&saidx->dst), (u_long) ntohl(sav->spi)));
  776                 m = NULL;               /* NB: free'd by m_pad */
  777                 error = ENOBUFS;
  778                 goto bad;
  779         }
  780 
  781         /*
  782          * Add padding: random, zero, or self-describing.
  783          * XXX catch unexpected setting
  784          */
  785         switch (sav->flags & SADB_X_EXT_PMASK) {
  786         case SADB_X_EXT_PRAND:
  787                 (void) read_random(pad, padding - 2);
  788                 break;
  789         case SADB_X_EXT_PZERO:
  790                 bzero(pad, padding - 2);
  791                 break;
  792         case SADB_X_EXT_PSEQ:
  793                 for (i = 0; i < padding - 2; i++)
  794                         pad[i] = i+1;
  795                 break;
  796         }
  797 
  798         /* Fix padding length and Next Protocol in padding itself. */
  799         pad[padding - 2] = padding - 2;
  800         m_copydata(m, protoff, sizeof(u_int8_t), pad + padding - 1);
  801 
  802         /* Fix Next Protocol in IPv4/IPv6 header. */
  803         prot = IPPROTO_ESP;
  804         m_copyback(m, protoff, sizeof(u_int8_t), (u_char *) &prot);
  805 
  806         /* Get crypto descriptors. */
  807         crp = crypto_getreq(esph && espx ? 2 : 1);
  808         if (crp == NULL) {
  809                 DPRINTF(("%s: failed to acquire crypto descriptors\n",
  810                         __func__));
  811                 espstat.esps_crypto++;
  812                 error = ENOBUFS;
  813                 goto bad;
  814         }
  815 
  816         if (espx) {
  817                 crde = crp->crp_desc;
  818                 crda = crde->crd_next;
  819 
  820                 /* Encryption descriptor. */
  821                 crde->crd_skip = skip + hlen;
  822                 crde->crd_len = m->m_pkthdr.len - (skip + hlen + alen);
  823                 crde->crd_flags = CRD_F_ENCRYPT;
  824                 crde->crd_inject = skip + hlen - sav->ivlen;
  825 
  826                 /* Encryption operation. */
  827                 crde->crd_alg = espx->type;
  828                 crde->crd_key = _KEYBUF(sav->key_enc);
  829                 crde->crd_klen = _KEYBITS(sav->key_enc);
  830                 /* XXX Rounds ? */
  831         } else
  832                 crda = crp->crp_desc;
  833 
  834         /* IPsec-specific opaque crypto info. */
  835         tc = (struct tdb_crypto *) malloc(sizeof(struct tdb_crypto),
  836                 M_XDATA, M_NOWAIT|M_ZERO);
  837         if (tc == NULL) {
  838                 crypto_freereq(crp);
  839                 DPRINTF(("%s: failed to allocate tdb_crypto\n", __func__));
  840                 espstat.esps_crypto++;
  841                 error = ENOBUFS;
  842                 goto bad;
  843         }
  844 
  845         /* Callback parameters */
  846         tc->tc_isr = isr;
  847         tc->tc_spi = sav->spi;
  848         tc->tc_dst = saidx->dst;
  849         tc->tc_proto = saidx->proto;
  850 
  851         /* Crypto operation descriptor. */
  852         crp->crp_ilen = m->m_pkthdr.len; /* Total input length. */
  853         crp->crp_flags = CRYPTO_F_IMBUF | CRYPTO_F_CBIFSYNC;
  854         crp->crp_buf = (caddr_t) m;
  855         crp->crp_callback = esp_output_cb;
  856         crp->crp_opaque = (caddr_t) tc;
  857         crp->crp_sid = sav->tdb_cryptoid;
  858 
  859         if (esph) {
  860                 /* Authentication descriptor. */
  861                 crda->crd_skip = skip;
  862                 crda->crd_len = m->m_pkthdr.len - (skip + alen);
  863                 crda->crd_inject = m->m_pkthdr.len - alen;
  864 
  865                 /* Authentication operation. */
  866                 crda->crd_alg = esph->type;
  867                 crda->crd_key = _KEYBUF(sav->key_auth);
  868                 crda->crd_klen = _KEYBITS(sav->key_auth);
  869         }
  870 
  871         return crypto_dispatch(crp);
  872 bad:
  873         if (m)
  874                 m_freem(m);
  875         return (error);
  876 }
  877 
  878 /*
  879  * ESP output callback from the crypto driver.
  880  */
  881 static int
  882 esp_output_cb(struct cryptop *crp)
  883 {
  884         struct tdb_crypto *tc;
  885         struct ipsecrequest *isr;
  886         struct secasvar *sav;
  887         struct mbuf *m;
  888         int err, error;
  889 
  890         NET_LOCK_GIANT();
  891 
  892         tc = (struct tdb_crypto *) crp->crp_opaque;
  893         IPSEC_ASSERT(tc != NULL, ("null opaque data area!"));
  894         m = (struct mbuf *) crp->crp_buf;
  895 
  896         isr = tc->tc_isr;
  897         IPSECREQUEST_LOCK(isr);
  898         sav = KEY_ALLOCSA(&tc->tc_dst, tc->tc_proto, tc->tc_spi);
  899         if (sav == NULL) {
  900                 espstat.esps_notdb++;
  901                 DPRINTF(("%s: SA gone during crypto (SA %s/%08lx proto %u)\n",
  902                     __func__, ipsec_address(&tc->tc_dst),
  903                     (u_long) ntohl(tc->tc_spi), tc->tc_proto));
  904                 error = ENOBUFS;                /*XXX*/
  905                 goto bad;
  906         }
  907         IPSEC_ASSERT(isr->sav == sav,
  908                 ("SA changed was %p now %p\n", isr->sav, sav));
  909 
  910         /* Check for crypto errors. */
  911         if (crp->crp_etype) {
  912                 /* Reset session ID. */
  913                 if (sav->tdb_cryptoid != 0)
  914                         sav->tdb_cryptoid = crp->crp_sid;
  915 
  916                 if (crp->crp_etype == EAGAIN) {
  917                         KEY_FREESAV(&sav);
  918                         IPSECREQUEST_UNLOCK(isr);
  919                         error = crypto_dispatch(crp);
  920                         NET_UNLOCK_GIANT();
  921                         return error;
  922                 }
  923 
  924                 espstat.esps_noxform++;
  925                 DPRINTF(("%s: crypto error %d\n", __func__, crp->crp_etype));
  926                 error = crp->crp_etype;
  927                 goto bad;
  928         }
  929 
  930         /* Shouldn't happen... */
  931         if (m == NULL) {
  932                 espstat.esps_crypto++;
  933                 DPRINTF(("%s: bogus returned buffer from crypto\n", __func__));
  934                 error = EINVAL;
  935                 goto bad;
  936         }
  937         espstat.esps_hist[sav->alg_enc]++;
  938         if (sav->tdb_authalgxform != NULL)
  939                 ahstat.ahs_hist[sav->alg_auth]++;
  940 
  941         /* Release crypto descriptors. */
  942         free(tc, M_XDATA);
  943         crypto_freereq(crp);
  944 
  945         /* NB: m is reclaimed by ipsec_process_done. */
  946         err = ipsec_process_done(m, isr);
  947         KEY_FREESAV(&sav);
  948         IPSECREQUEST_UNLOCK(isr);
  949         NET_UNLOCK_GIANT();
  950         return err;
  951 bad:
  952         if (sav)
  953                 KEY_FREESAV(&sav);
  954         IPSECREQUEST_UNLOCK(isr);
  955         if (m)
  956                 m_freem(m);
  957         free(tc, M_XDATA);
  958         crypto_freereq(crp);
  959         NET_UNLOCK_GIANT();
  960         return error;
  961 }
  962 
  963 static struct xformsw esp_xformsw = {
  964         XF_ESP,         XFT_CONF|XFT_AUTH,      "IPsec ESP",
  965         esp_init,       esp_zeroize,            esp_input,
  966         esp_output
  967 };
  968 
  969 static void
  970 esp_attach(void)
  971 {
  972 #define MAXIV(xform)                                    \
  973         if (xform.blocksize > esp_max_ivlen)            \
  974                 esp_max_ivlen = xform.blocksize         \
  975 
  976         esp_max_ivlen = 0;
  977         MAXIV(enc_xform_des);           /* SADB_EALG_DESCBC */
  978         MAXIV(enc_xform_3des);          /* SADB_EALG_3DESCBC */
  979         MAXIV(enc_xform_rijndael128);   /* SADB_X_EALG_AES */
  980         MAXIV(enc_xform_blf);           /* SADB_X_EALG_BLOWFISHCBC */
  981         MAXIV(enc_xform_cast5);         /* SADB_X_EALG_CAST128CBC */
  982         MAXIV(enc_xform_skipjack);      /* SADB_X_EALG_SKIPJACK */
  983         MAXIV(enc_xform_null);          /* SADB_EALG_NULL */
  984 
  985         xform_register(&esp_xformsw);
  986 #undef MAXIV
  987 }
  988 SYSINIT(esp_xform_init, SI_SUB_PROTO_DOMAIN, SI_ORDER_MIDDLE, esp_attach, NULL);

Cache object: 030e38434c04a9353b8386dd583a86f8


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