1 /* 2 * SSL session cache implementation 3 * 4 * Copyright (C) 2006-2015, ARM Limited, All Rights Reserved 5 * SPDX-License-Identifier: Apache-2.0 6 * 7 * Licensed under the Apache License, Version 2.0 (the "License"); you may 8 * not use this file except in compliance with the License. 9 * You may obtain a copy of the License at 10 * 11 * http://www.apache.org/licenses/LICENSE-2.0 12 * 13 * Unless required by applicable law or agreed to in writing, software 14 * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT 15 * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 16 * See the License for the specific language governing permissions and 17 * limitations under the License. 18 * 19 * This file is part of mbed TLS (https://tls.mbed.org) 20 */ 21 /* 22 * These session callbacks use a simple chained list 23 * to store and retrieve the session information. 24 */ 25 26 #if !defined(MBEDTLS_CONFIG_FILE) 27 #include "mbedtls/config.h" 28 #else 29 #include MBEDTLS_CONFIG_FILE 30 #endif 31 32 #if defined(MBEDTLS_SSL_CACHE_C) 33 34 #if defined(MBEDTLS_PLATFORM_C) 35 #include "mbedtls/platform.h" 36 #else 37 #include <stdlib.h> 38 #define mbedtls_calloc calloc 39 #define mbedtls_free free 40 #endif 41 42 #include "mbedtls/ssl_cache.h" 43 44 #include <string.h> 45 46 void mbedtls_ssl_cache_init( mbedtls_ssl_cache_context *cache ) 47 { 48 memset( cache, 0, sizeof( mbedtls_ssl_cache_context ) ); 49 50 cache->timeout = MBEDTLS_SSL_CACHE_DEFAULT_TIMEOUT; 51 cache->max_entries = MBEDTLS_SSL_CACHE_DEFAULT_MAX_ENTRIES; 52 53 #if defined(MBEDTLS_THREADING_C) 54 mbedtls_mutex_init( &cache->mutex ); 55 #endif 56 } 57 58 int mbedtls_ssl_cache_get( void *data, mbedtls_ssl_session *session ) 59 { 60 int ret = 1; 61 #if defined(MBEDTLS_HAVE_TIME) 62 mbedtls_time_t t = mbedtls_time( NULL ); 63 #endif 64 mbedtls_ssl_cache_context *cache = (mbedtls_ssl_cache_context *) data; 65 mbedtls_ssl_cache_entry *cur, *entry; 66 67 #if defined(MBEDTLS_THREADING_C) 68 if( mbedtls_mutex_lock( &cache->mutex ) != 0 ) 69 return( 1 ); 70 #endif 71 72 cur = cache->chain; 73 entry = NULL; 74 75 while( cur != NULL ) 76 { 77 entry = cur; 78 cur = cur->next; 79 80 #if defined(MBEDTLS_HAVE_TIME) 81 if( cache->timeout != 0 && 82 (int) ( t - entry->timestamp ) > cache->timeout ) 83 continue; 84 #endif 85 86 if( session->ciphersuite != entry->session.ciphersuite || 87 session->compression != entry->session.compression || 88 session->id_len != entry->session.id_len ) 89 continue; 90 91 if( memcmp( session->id, entry->session.id, 92 entry->session.id_len ) != 0 ) 93 continue; 94 95 memcpy( session->master, entry->session.master, 48 ); 96 97 session->verify_result = entry->session.verify_result; 98 99 #if defined(MBEDTLS_X509_CRT_PARSE_C) 100 /* 101 * Restore peer certificate (without rest of the original chain) 102 */ 103 if( entry->peer_cert.p != NULL ) 104 { 105 if( ( session->peer_cert = mbedtls_calloc( 1, 106 sizeof(mbedtls_x509_crt) ) ) == NULL ) 107 { 108 ret = 1; 109 goto exit; 110 } 111 112 mbedtls_x509_crt_init( session->peer_cert ); 113 if( mbedtls_x509_crt_parse( session->peer_cert, entry->peer_cert.p, 114 entry->peer_cert.len ) != 0 ) 115 { 116 mbedtls_free( session->peer_cert ); 117 session->peer_cert = NULL; 118 ret = 1; 119 goto exit; 120 } 121 } 122 #endif /* MBEDTLS_X509_CRT_PARSE_C */ 123 124 ret = 0; 125 goto exit; 126 } 127 128 exit: 129 #if defined(MBEDTLS_THREADING_C) 130 if( mbedtls_mutex_unlock( &cache->mutex ) != 0 ) 131 ret = 1; 132 #endif 133 134 return( ret ); 135 } 136 137 int mbedtls_ssl_cache_set( void *data, const mbedtls_ssl_session *session ) 138 { 139 int ret = 1; 140 #if defined(MBEDTLS_HAVE_TIME) 141 mbedtls_time_t t = mbedtls_time( NULL ), oldest = 0; 142 mbedtls_ssl_cache_entry *old = NULL; 143 #endif 144 mbedtls_ssl_cache_context *cache = (mbedtls_ssl_cache_context *) data; 145 mbedtls_ssl_cache_entry *cur, *prv; 146 int count = 0; 147 148 #if defined(MBEDTLS_THREADING_C) 149 if( ( ret = mbedtls_mutex_lock( &cache->mutex ) ) != 0 ) 150 return( ret ); 151 #endif 152 153 cur = cache->chain; 154 prv = NULL; 155 156 while( cur != NULL ) 157 { 158 count++; 159 160 #if defined(MBEDTLS_HAVE_TIME) 161 if( cache->timeout != 0 && 162 (int) ( t - cur->timestamp ) > cache->timeout ) 163 { 164 cur->timestamp = t; 165 break; /* expired, reuse this slot, update timestamp */ 166 } 167 #endif 168 169 if( memcmp( session->id, cur->session.id, cur->session.id_len ) == 0 ) 170 break; /* client reconnected, keep timestamp for session id */ 171 172 #if defined(MBEDTLS_HAVE_TIME) 173 if( oldest == 0 || cur->timestamp < oldest ) 174 { 175 oldest = cur->timestamp; 176 old = cur; 177 } 178 #endif 179 180 prv = cur; 181 cur = cur->next; 182 } 183 184 if( cur == NULL ) 185 { 186 #if defined(MBEDTLS_HAVE_TIME) 187 /* 188 * Reuse oldest entry if max_entries reached 189 */ 190 if( count >= cache->max_entries ) 191 { 192 if( old == NULL ) 193 { 194 ret = 1; 195 goto exit; 196 } 197 198 cur = old; 199 } 200 #else /* MBEDTLS_HAVE_TIME */ 201 /* 202 * Reuse first entry in chain if max_entries reached, 203 * but move to last place 204 */ 205 if( count >= cache->max_entries ) 206 { 207 if( cache->chain == NULL ) 208 { 209 ret = 1; 210 goto exit; 211 } 212 213 cur = cache->chain; 214 cache->chain = cur->next; 215 cur->next = NULL; 216 prv->next = cur; 217 } 218 #endif /* MBEDTLS_HAVE_TIME */ 219 else 220 { 221 /* 222 * max_entries not reached, create new entry 223 */ 224 cur = mbedtls_calloc( 1, sizeof(mbedtls_ssl_cache_entry) ); 225 if( cur == NULL ) 226 { 227 ret = 1; 228 goto exit; 229 } 230 231 if( prv == NULL ) 232 cache->chain = cur; 233 else 234 prv->next = cur; 235 } 236 237 #if defined(MBEDTLS_HAVE_TIME) 238 cur->timestamp = t; 239 #endif 240 } 241 242 memcpy( &cur->session, session, sizeof( mbedtls_ssl_session ) ); 243 244 #if defined(MBEDTLS_X509_CRT_PARSE_C) 245 /* 246 * If we're reusing an entry, free its certificate first 247 */ 248 if( cur->peer_cert.p != NULL ) 249 { 250 mbedtls_free( cur->peer_cert.p ); 251 memset( &cur->peer_cert, 0, sizeof(mbedtls_x509_buf) ); 252 } 253 254 /* 255 * Store peer certificate 256 */ 257 if( session->peer_cert != NULL ) 258 { 259 cur->peer_cert.p = mbedtls_calloc( 1, session->peer_cert->raw.len ); 260 if( cur->peer_cert.p == NULL ) 261 { 262 ret = 1; 263 goto exit; 264 } 265 266 memcpy( cur->peer_cert.p, session->peer_cert->raw.p, 267 session->peer_cert->raw.len ); 268 cur->peer_cert.len = session->peer_cert->raw.len; 269 270 cur->session.peer_cert = NULL; 271 } 272 #endif /* MBEDTLS_X509_CRT_PARSE_C */ 273 274 ret = 0; 275 276 exit: 277 #if defined(MBEDTLS_THREADING_C) 278 if( mbedtls_mutex_unlock( &cache->mutex ) != 0 ) 279 ret = 1; 280 #endif 281 282 return( ret ); 283 } 284 285 #if defined(MBEDTLS_HAVE_TIME) 286 void mbedtls_ssl_cache_set_timeout( mbedtls_ssl_cache_context *cache, int timeout ) 287 { 288 if( timeout < 0 ) timeout = 0; 289 290 cache->timeout = timeout; 291 } 292 #endif /* MBEDTLS_HAVE_TIME */ 293 294 void mbedtls_ssl_cache_set_max_entries( mbedtls_ssl_cache_context *cache, int max ) 295 { 296 if( max < 0 ) max = 0; 297 298 cache->max_entries = max; 299 } 300 301 void mbedtls_ssl_cache_free( mbedtls_ssl_cache_context *cache ) 302 { 303 mbedtls_ssl_cache_entry *cur, *prv; 304 305 cur = cache->chain; 306 307 while( cur != NULL ) 308 { 309 prv = cur; 310 cur = cur->next; 311 312 mbedtls_ssl_session_free( &prv->session ); 313 314 #if defined(MBEDTLS_X509_CRT_PARSE_C) 315 mbedtls_free( prv->peer_cert.p ); 316 #endif /* MBEDTLS_X509_CRT_PARSE_C */ 317 318 mbedtls_free( prv ); 319 } 320 321 #if defined(MBEDTLS_THREADING_C) 322 mbedtls_mutex_free( &cache->mutex ); 323 #endif 324 } 325 326 #endif /* MBEDTLS_SSL_CACHE_C */ 327