ssl_cache.c

00001 /*
00002  *  SSL session cache implementation
00003  *
00004  *  Copyright (C) 2006-2014, Brainspark B.V.
00005  *
00006  *  This file is part of PolarSSL (http://www.polarssl.org)
00007  *  Lead Maintainer: Paul Bakker <polarssl_maintainer at polarssl.org>
00008  *
00009  *  All rights reserved.
00010  *
00011  *  This program is free software; you can redistribute it and/or modify
00012  *  it under the terms of the GNU General Public License as published by
00013  *  the Free Software Foundation; either version 2 of the License, or
00014  *  (at your option) any later version.
00015  *
00016  *  This program is distributed in the hope that it will be useful,
00017  *  but WITHOUT ANY WARRANTY; without even the implied warranty of
00018  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
00019  *  GNU General Public License for more details.
00020  *
00021  *  You should have received a copy of the GNU General Public License along
00022  *  with this program; if not, write to the Free Software Foundation, Inc.,
00023  *  51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
00024  */
00025 /*
00026  * These session callbacks use a simple chained list
00027  * to store and retrieve the session information.
00028  */
00029 
00030 #if !defined(POLARSSL_CONFIG_FILE)
00031 #include "polarssl/config.h"
00032 #else
00033 #include POLARSSL_CONFIG_FILE
00034 #endif
00035 
00036 #if defined(POLARSSL_SSL_CACHE_C)
00037 
00038 #include "polarssl/ssl_cache.h"
00039 
00040 #if defined(POLARSSL_PLATFORM_C)
00041 #include "polarssl/platform.h"
00042 #else
00043 #define polarssl_malloc     malloc
00044 #define polarssl_free       free
00045 #endif
00046 
00047 #include <stdlib.h>
00048 
00049 void ssl_cache_init( ssl_cache_context *cache )
00050 {
00051     memset( cache, 0, sizeof( ssl_cache_context ) );
00052 
00053     cache->timeout  = SSL_CACHE_DEFAULT_TIMEOUT;
00054     cache->max_entries  = SSL_CACHE_DEFAULT_MAX_ENTRIES;
00055 
00056 #if defined(POLARSSL_THREADING_C)
00057     polarssl_mutex_init( &cache->mutex  );
00058 #endif
00059 }
00060 
00061 int ssl_cache_get( void *data, ssl_session *session )
00062 {
00063     int ret = 1;
00064 #if defined(POLARSSL_HAVE_TIME)
00065     time_t t = time( NULL );
00066 #endif
00067     ssl_cache_context *cache = (ssl_cache_context *) data;
00068     ssl_cache_entry *cur, *entry;
00069 
00070 #if defined(POLARSSL_THREADING_C)
00071     if( polarssl_mutex_lock( &cache->mutex  ) != 0 )
00072         return( 1 );
00073 #endif
00074 
00075     cur = cache->chain ;
00076     entry = NULL;
00077 
00078     while( cur != NULL )
00079     {
00080         entry = cur;
00081         cur = cur->next ;
00082 
00083 #if defined(POLARSSL_HAVE_TIME)
00084         if( cache->timeout  != 0 &&
00085             (int) ( t - entry->timestamp  ) > cache->timeout  )
00086             continue;
00087 #endif
00088 
00089         if( session->ciphersuite != entry->session .ciphersuite ||
00090             session->compression != entry->session .compression ||
00091             session->length != entry->session .length )
00092             continue;
00093 
00094         if( memcmp( session->id, entry->session .id,
00095                     entry->session .length ) != 0 )
00096             continue;
00097 
00098         memcpy( session->master, entry->session .master, 48 );
00099 
00100         session->verify_result = entry->session .verify_result;
00101 
00102 #if defined(POLARSSL_X509_CRT_PARSE_C)
00103         /*
00104          * Restore peer certificate (without rest of the original chain)
00105          */
00106         if( entry->peer_cert .p != NULL )
00107         {
00108             session->peer_cert =
00109                 (x509_crt *) polarssl_malloc( sizeof(x509_crt) );
00110 
00111             if( session->peer_cert == NULL )
00112             {
00113                 ret = 1;
00114                 goto exit;
00115             }
00116 
00117             x509_crt_init( session->peer_cert );
00118             if( x509_crt_parse( session->peer_cert, entry->peer_cert .p,
00119                                 entry->peer_cert .len ) != 0 )
00120             {
00121                 polarssl_free( session->peer_cert );
00122                 session->peer_cert = NULL;
00123                 ret = 1;
00124                 goto exit;
00125             }
00126         }
00127 #endif /* POLARSSL_X509_CRT_PARSE_C */
00128 
00129         ret = 0;
00130         goto exit;
00131     }
00132 
00133 exit:
00134 #if defined(POLARSSL_THREADING_C)
00135     if( polarssl_mutex_unlock( &cache->mutex  ) != 0 )
00136         ret = 1;
00137 #endif
00138 
00139     return( ret );
00140 }
00141 
00142 int ssl_cache_set( void *data, const ssl_session *session )
00143 {
00144     int ret = 1;
00145 #if defined(POLARSSL_HAVE_TIME)
00146     time_t t = time( NULL ), oldest = 0;
00147     ssl_cache_entry *old = NULL;
00148 #endif
00149     ssl_cache_context *cache = (ssl_cache_context *) data;
00150     ssl_cache_entry *cur, *prv;
00151     int count = 0;
00152 
00153 #if defined(POLARSSL_THREADING_C)
00154     if( ( ret = polarssl_mutex_lock( &cache->mutex  ) ) != 0 )
00155         return( ret );
00156 #endif
00157 
00158     cur = cache->chain ;
00159     prv = NULL;
00160 
00161     while( cur != NULL )
00162     {
00163         count++;
00164 
00165 #if defined(POLARSSL_HAVE_TIME)
00166         if( cache->timeout  != 0 &&
00167             (int) ( t - cur->timestamp  ) > cache->timeout  )
00168         {
00169             cur->timestamp  = t;
00170             break; /* expired, reuse this slot, update timestamp */
00171         }
00172 #endif
00173 
00174         if( memcmp( session->id, cur->session .id, cur->session .length ) == 0 )
00175             break; /* client reconnected, keep timestamp for session id */
00176 
00177 #if defined(POLARSSL_HAVE_TIME)
00178         if( oldest == 0 || cur->timestamp  < oldest )
00179         {
00180             oldest = cur->timestamp ;
00181             old = cur;
00182         }
00183 #endif
00184 
00185         prv = cur;
00186         cur = cur->next ;
00187     }
00188 
00189     if( cur == NULL )
00190     {
00191 #if defined(POLARSSL_HAVE_TIME)
00192         /*
00193          * Reuse oldest entry if max_entries reached
00194          */
00195         if( count >= cache->max_entries  )
00196         {
00197             if( old == NULL )
00198             {
00199                 ret = 1;
00200                 goto exit;
00201             }
00202 
00203             cur = old;
00204         }
00205 #else /* POLARSSL_HAVE_TIME */
00206         /*
00207          * Reuse first entry in chain if max_entries reached,
00208          * but move to last place
00209          */
00210         if( count >= cache->max_entries  )
00211         {
00212             if( cache->chain  == NULL )
00213             {
00214                 ret = 1;
00215                 goto exit;
00216             }
00217 
00218             cur = cache->chain ;
00219             cache->chain  = cur->next ;
00220             cur->next  = NULL;
00221             prv->next  = cur;
00222         }
00223 #endif /* POLARSSL_HAVE_TIME */
00224         else
00225         {
00226             /*
00227              * max_entries not reached, create new entry
00228              */
00229             cur = (ssl_cache_entry *)
00230                         polarssl_malloc( sizeof(ssl_cache_entry) );
00231             if( cur == NULL )
00232             {
00233                 ret = 1;
00234                 goto exit;
00235             }
00236 
00237             memset( cur, 0, sizeof(ssl_cache_entry) );
00238 
00239             if( prv == NULL )
00240                 cache->chain  = cur;
00241             else
00242                 prv->next  = cur;
00243         }
00244 
00245 #if defined(POLARSSL_HAVE_TIME)
00246         cur->timestamp  = t;
00247 #endif
00248     }
00249 
00250     memcpy( &cur->session , session, sizeof( ssl_session ) );
00251 
00252 #if defined(POLARSSL_X509_CRT_PARSE_C)
00253     /*
00254      * If we're reusing an entry, free its certificate first
00255      */
00256     if( cur->peer_cert .p != NULL )
00257     {
00258         polarssl_free( cur->peer_cert .p );
00259         memset( &cur->peer_cert , 0, sizeof(x509_buf) );
00260     }
00261 
00262     /*
00263      * Store peer certificate
00264      */
00265     if( session->peer_cert != NULL )
00266     {
00267         cur->peer_cert .p = (unsigned char *)
00268                                 polarssl_malloc( session->peer_cert->raw.len );
00269         if( cur->peer_cert .p == NULL )
00270         {
00271             ret = 1;
00272             goto exit;
00273         }
00274 
00275         memcpy( cur->peer_cert .p, session->peer_cert->raw.p,
00276                 session->peer_cert->raw.len );
00277         cur->peer_cert .len = session->peer_cert->raw.len;
00278 
00279         cur->session .peer_cert = NULL;
00280     }
00281 #endif /* POLARSSL_X509_CRT_PARSE_C */
00282 
00283     ret = 0;
00284 
00285 exit:
00286 #if defined(POLARSSL_THREADING_C)
00287     if( polarssl_mutex_unlock( &cache->mutex  ) != 0 )
00288         ret = 1;
00289 #endif
00290 
00291     return( ret );
00292 }
00293 
00294 #if defined(POLARSSL_HAVE_TIME)
00295 void ssl_cache_set_timeout( ssl_cache_context *cache, int timeout )
00296 {
00297     if( timeout < 0 ) timeout = 0;
00298 
00299     cache->timeout  = timeout;
00300 }
00301 #endif /* POLARSSL_HAVE_TIME */
00302 
00303 void ssl_cache_set_max_entries( ssl_cache_context *cache, int max )
00304 {
00305     if( max < 0 ) max = 0;
00306 
00307     cache->max_entries  = max;
00308 }
00309 
00310 void ssl_cache_free( ssl_cache_context *cache )
00311 {
00312     ssl_cache_entry *cur, *prv;
00313 
00314     cur = cache->chain ;
00315 
00316     while( cur != NULL )
00317     {
00318         prv = cur;
00319         cur = cur->next ;
00320 
00321         ssl_session_free( &prv->session  );
00322 
00323 #if defined(POLARSSL_X509_CRT_PARSE_C)
00324         if( prv->peer_cert .p != NULL )
00325             polarssl_free( prv->peer_cert .p );
00326 #endif /* POLARSSL_X509_CRT_PARSE_C */
00327 
00328         polarssl_free( prv );
00329     }
00330 
00331 #if defined(POLARSSL_THREADING_C)
00332     polarssl_mutex_free( &cache->mutex  );
00333 #endif
00334 }
00335 
00336 #endif /* POLARSSL_SSL_CACHE_C */
00337 
00338