ssl_cache.c

00001 /*
00002  *  SSL session cache implementation
00003  *
00004  *  Copyright (C) 2006-2014, ARM Limited, All Rights Reserved
00005  *
00006  *  This file is part of mbed TLS (https://tls.mbed.org)
00007  *
00008  *  This program is free software; you can redistribute it and/or modify
00009  *  it under the terms of the GNU General Public License as published by
00010  *  the Free Software Foundation; either version 2 of the License, or
00011  *  (at your option) any later version.
00012  *
00013  *  This program is distributed in the hope that it will be useful,
00014  *  but WITHOUT ANY WARRANTY; without even the implied warranty of
00015  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
00016  *  GNU General Public License for more details.
00017  *
00018  *  You should have received a copy of the GNU General Public License along
00019  *  with this program; if not, write to the Free Software Foundation, Inc.,
00020  *  51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
00021  */
00022 /*
00023  * These session callbacks use a simple chained list
00024  * to store and retrieve the session information.
00025  */
00026 
00027 #if !defined(POLARSSL_CONFIG_FILE)
00028 #include "polarssl/config.h"
00029 #else
00030 #include POLARSSL_CONFIG_FILE
00031 #endif
00032 
00033 #if defined(POLARSSL_SSL_CACHE_C)
00034 
00035 #include "polarssl/ssl_cache.h"
00036 
00037 #include <string.h>
00038 
00039 #if defined(POLARSSL_PLATFORM_C)
00040 #include "polarssl/platform.h"
00041 #else
00042 #include <stdlib.h>
00043 #define polarssl_malloc     malloc
00044 #define polarssl_free       free
00045 #endif
00046 
00047 void ssl_cache_init( ssl_cache_context *cache )
00048 {
00049     memset( cache, 0, sizeof( ssl_cache_context ) );
00050 
00051     cache->timeout  = SSL_CACHE_DEFAULT_TIMEOUT;
00052     cache->max_entries  = SSL_CACHE_DEFAULT_MAX_ENTRIES;
00053 
00054 #if defined(POLARSSL_THREADING_C)
00055     polarssl_mutex_init( &cache->mutex  );
00056 #endif
00057 }
00058 
00059 int ssl_cache_get( void *data, ssl_session *session )
00060 {
00061     int ret = 1;
00062 #if defined(POLARSSL_HAVE_TIME)
00063     time_t t = time( NULL );
00064 #endif
00065     ssl_cache_context *cache = (ssl_cache_context *) data;
00066     ssl_cache_entry *cur, *entry;
00067 
00068 #if defined(POLARSSL_THREADING_C)
00069     if( polarssl_mutex_lock( &cache->mutex  ) != 0 )
00070         return( 1 );
00071 #endif
00072 
00073     cur = cache->chain ;
00074     entry = NULL;
00075 
00076     while( cur != NULL )
00077     {
00078         entry = cur;
00079         cur = cur->next ;
00080 
00081 #if defined(POLARSSL_HAVE_TIME)
00082         if( cache->timeout  != 0 &&
00083             (int) ( t - entry->timestamp  ) > cache->timeout  )
00084             continue;
00085 #endif
00086 
00087         if( session->ciphersuite != entry->session .ciphersuite ||
00088             session->compression != entry->session .compression ||
00089             session->length != entry->session .length )
00090             continue;
00091 
00092         if( memcmp( session->id, entry->session .id,
00093                     entry->session .length ) != 0 )
00094             continue;
00095 
00096         memcpy( session->master, entry->session .master, 48 );
00097 
00098         session->verify_result = entry->session .verify_result;
00099 
00100 #if defined(POLARSSL_X509_CRT_PARSE_C)
00101         /*
00102          * Restore peer certificate (without rest of the original chain)
00103          */
00104         if( entry->peer_cert .p != NULL )
00105         {
00106             if( ( session->peer_cert = polarssl_malloc(
00107                                  sizeof(x509_crt) ) ) == NULL )
00108             {
00109                 ret = 1;
00110                 goto exit;
00111             }
00112 
00113             x509_crt_init( session->peer_cert );
00114             if( x509_crt_parse( session->peer_cert, entry->peer_cert .p,
00115                                 entry->peer_cert .len ) != 0 )
00116             {
00117                 polarssl_free( session->peer_cert );
00118                 session->peer_cert = NULL;
00119                 ret = 1;
00120                 goto exit;
00121             }
00122         }
00123 #endif /* POLARSSL_X509_CRT_PARSE_C */
00124 
00125         ret = 0;
00126         goto exit;
00127     }
00128 
00129 exit:
00130 #if defined(POLARSSL_THREADING_C)
00131     if( polarssl_mutex_unlock( &cache->mutex  ) != 0 )
00132         ret = 1;
00133 #endif
00134 
00135     return( ret );
00136 }
00137 
00138 int ssl_cache_set( void *data, const ssl_session *session )
00139 {
00140     int ret = 1;
00141 #if defined(POLARSSL_HAVE_TIME)
00142     time_t t = time( NULL ), oldest = 0;
00143     ssl_cache_entry *old = NULL;
00144 #endif
00145     ssl_cache_context *cache = (ssl_cache_context *) data;
00146     ssl_cache_entry *cur, *prv;
00147     int count = 0;
00148 
00149 #if defined(POLARSSL_THREADING_C)
00150     if( ( ret = polarssl_mutex_lock( &cache->mutex  ) ) != 0 )
00151         return( ret );
00152 #endif
00153 
00154     cur = cache->chain ;
00155     prv = NULL;
00156 
00157     while( cur != NULL )
00158     {
00159         count++;
00160 
00161 #if defined(POLARSSL_HAVE_TIME)
00162         if( cache->timeout  != 0 &&
00163             (int) ( t - cur->timestamp  ) > cache->timeout  )
00164         {
00165             cur->timestamp  = t;
00166             break; /* expired, reuse this slot, update timestamp */
00167         }
00168 #endif
00169 
00170         if( memcmp( session->id, cur->session .id, cur->session .length ) == 0 )
00171             break; /* client reconnected, keep timestamp for session id */
00172 
00173 #if defined(POLARSSL_HAVE_TIME)
00174         if( oldest == 0 || cur->timestamp  < oldest )
00175         {
00176             oldest = cur->timestamp ;
00177             old = cur;
00178         }
00179 #endif
00180 
00181         prv = cur;
00182         cur = cur->next ;
00183     }
00184 
00185     if( cur == NULL )
00186     {
00187 #if defined(POLARSSL_HAVE_TIME)
00188         /*
00189          * Reuse oldest entry if max_entries reached
00190          */
00191         if( count >= cache->max_entries  )
00192         {
00193             if( old == NULL )
00194             {
00195                 ret = 1;
00196                 goto exit;
00197             }
00198 
00199             cur = old;
00200         }
00201 #else /* POLARSSL_HAVE_TIME */
00202         /*
00203          * Reuse first entry in chain if max_entries reached,
00204          * but move to last place
00205          */
00206         if( count >= cache->max_entries  )
00207         {
00208             if( cache->chain  == NULL )
00209             {
00210                 ret = 1;
00211                 goto exit;
00212             }
00213 
00214             cur = cache->chain ;
00215             cache->chain  = cur->next ;
00216             cur->next  = NULL;
00217             prv->next  = cur;
00218         }
00219 #endif /* POLARSSL_HAVE_TIME */
00220         else
00221         {
00222             /*
00223              * max_entries not reached, create new entry
00224              */
00225             cur = polarssl_malloc( sizeof(ssl_cache_entry) );
00226             if( cur == NULL )
00227             {
00228                 ret = 1;
00229                 goto exit;
00230             }
00231 
00232             memset( cur, 0, sizeof(ssl_cache_entry) );
00233 
00234             if( prv == NULL )
00235                 cache->chain  = cur;
00236             else
00237                 prv->next  = cur;
00238         }
00239 
00240 #if defined(POLARSSL_HAVE_TIME)
00241         cur->timestamp  = t;
00242 #endif
00243     }
00244 
00245     memcpy( &cur->session , session, sizeof( ssl_session ) );
00246 
00247 #if defined(POLARSSL_X509_CRT_PARSE_C)
00248     /*
00249      * If we're reusing an entry, free its certificate first
00250      */
00251     if( cur->peer_cert .p != NULL )
00252     {
00253         polarssl_free( cur->peer_cert .p );
00254         memset( &cur->peer_cert , 0, sizeof(x509_buf) );
00255     }
00256 
00257     /*
00258      * Store peer certificate
00259      */
00260     if( session->peer_cert != NULL )
00261     {
00262         cur->peer_cert .p = polarssl_malloc( session->peer_cert->raw.len );
00263         if( cur->peer_cert .p == NULL )
00264         {
00265             ret = 1;
00266             goto exit;
00267         }
00268 
00269         memcpy( cur->peer_cert .p, session->peer_cert->raw.p,
00270                 session->peer_cert->raw.len );
00271         cur->peer_cert .len = session->peer_cert->raw.len;
00272 
00273         cur->session .peer_cert = NULL;
00274     }
00275 #endif /* POLARSSL_X509_CRT_PARSE_C */
00276 
00277     ret = 0;
00278 
00279 exit:
00280 #if defined(POLARSSL_THREADING_C)
00281     if( polarssl_mutex_unlock( &cache->mutex  ) != 0 )
00282         ret = 1;
00283 #endif
00284 
00285     return( ret );
00286 }
00287 
00288 #if defined(POLARSSL_HAVE_TIME)
00289 void ssl_cache_set_timeout( ssl_cache_context *cache, int timeout )
00290 {
00291     if( timeout < 0 ) timeout = 0;
00292 
00293     cache->timeout  = timeout;
00294 }
00295 #endif /* POLARSSL_HAVE_TIME */
00296 
00297 void ssl_cache_set_max_entries( ssl_cache_context *cache, int max )
00298 {
00299     if( max < 0 ) max = 0;
00300 
00301     cache->max_entries  = max;
00302 }
00303 
00304 void ssl_cache_free( ssl_cache_context *cache )
00305 {
00306     ssl_cache_entry *cur, *prv;
00307 
00308     cur = cache->chain ;
00309 
00310     while( cur != NULL )
00311     {
00312         prv = cur;
00313         cur = cur->next ;
00314 
00315         ssl_session_free( &prv->session  );
00316 
00317 #if defined(POLARSSL_X509_CRT_PARSE_C)
00318         polarssl_free( prv->peer_cert .p );
00319 #endif /* POLARSSL_X509_CRT_PARSE_C */
00320 
00321         polarssl_free( prv );
00322     }
00323 
00324 #if defined(POLARSSL_THREADING_C)
00325     polarssl_mutex_free( &cache->mutex  );
00326 #endif
00327 }
00328 
00329 #endif /* POLARSSL_SSL_CACHE_C */
00330