1 /* 2 * SSL session cache implementation 3 * 4 * Copyright The Mbed TLS Contributors 5 * SPDX-License-Identifier: Apache-2.0 OR GPL-2.0-or-later 6 * 7 * This file is provided under the Apache License 2.0, or the 8 * GNU General Public License v2.0 or later. 9 * 10 * ********** 11 * Apache License 2.0: 12 * 13 * Licensed under the Apache License, Version 2.0 (the "License"); you may 14 * not use this file except in compliance with the License. 15 * You may obtain a copy of the License at 16 * 17 * http://www.apache.org/licenses/LICENSE-2.0 18 * 19 * Unless required by applicable law or agreed to in writing, software 20 * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT 21 * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 22 * See the License for the specific language governing permissions and 23 * limitations under the License. 24 * 25 * ********** 26 * 27 * ********** 28 * GNU General Public License v2.0 or later: 29 * 30 * This program is free software; you can redistribute it and/or modify 31 * it under the terms of the GNU General Public License as published by 32 * the Free Software Foundation; either version 2 of the License, or 33 * (at your option) any later version. 34 * 35 * This program is distributed in the hope that it will be useful, 36 * but WITHOUT ANY WARRANTY; without even the implied warranty of 37 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 38 * GNU General Public License for more details. 39 * 40 * You should have received a copy of the GNU General Public License along 41 * with this program; if not, write to the Free Software Foundation, Inc., 42 * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA. 43 * 44 * ********** 45 */ 46 /* 47 * These session callbacks use a simple chained list 48 * to store and retrieve the session information. 49 */ 50 51 #if !defined(MBEDTLS_CONFIG_FILE) 52 #include "mbedtls/config.h" 53 #else 54 #include MBEDTLS_CONFIG_FILE 55 #endif 56 57 #if defined(MBEDTLS_SSL_CACHE_C) 58 59 #if defined(MBEDTLS_PLATFORM_C) 60 #include "mbedtls/platform.h" 61 #else 62 #include <stdlib.h> 63 #define mbedtls_calloc calloc 64 #define mbedtls_free free 65 #endif 66 67 #include "mbedtls/ssl_cache.h" 68 69 #include <string.h> 70 71 void mbedtls_ssl_cache_init( mbedtls_ssl_cache_context *cache ) 72 { 73 memset( cache, 0, sizeof( mbedtls_ssl_cache_context ) ); 74 75 cache->timeout = MBEDTLS_SSL_CACHE_DEFAULT_TIMEOUT; 76 cache->max_entries = MBEDTLS_SSL_CACHE_DEFAULT_MAX_ENTRIES; 77 78 #if defined(MBEDTLS_THREADING_C) 79 mbedtls_mutex_init( &cache->mutex ); 80 #endif 81 } 82 83 int mbedtls_ssl_cache_get( void *data, mbedtls_ssl_session *session ) 84 { 85 int ret = 1; 86 #if defined(MBEDTLS_HAVE_TIME) 87 mbedtls_time_t t = mbedtls_time( NULL ); 88 #endif 89 mbedtls_ssl_cache_context *cache = (mbedtls_ssl_cache_context *) data; 90 mbedtls_ssl_cache_entry *cur, *entry; 91 92 #if defined(MBEDTLS_THREADING_C) 93 if( mbedtls_mutex_lock( &cache->mutex ) != 0 ) 94 return( 1 ); 95 #endif 96 97 cur = cache->chain; 98 entry = NULL; 99 100 while( cur != NULL ) 101 { 102 entry = cur; 103 cur = cur->next; 104 105 #if defined(MBEDTLS_HAVE_TIME) 106 if( cache->timeout != 0 && 107 (int) ( t - entry->timestamp ) > cache->timeout ) 108 continue; 109 #endif 110 111 if( session->ciphersuite != entry->session.ciphersuite || 112 session->compression != entry->session.compression || 113 session->id_len != entry->session.id_len ) 114 continue; 115 116 if( memcmp( session->id, entry->session.id, 117 entry->session.id_len ) != 0 ) 118 continue; 119 120 memcpy( session->master, entry->session.master, 48 ); 121 122 session->verify_result = entry->session.verify_result; 123 124 #if defined(MBEDTLS_X509_CRT_PARSE_C) 125 /* 126 * Restore peer certificate (without rest of the original chain) 127 */ 128 if( entry->peer_cert.p != NULL ) 129 { 130 if( ( session->peer_cert = mbedtls_calloc( 1, 131 sizeof(mbedtls_x509_crt) ) ) == NULL ) 132 { 133 ret = 1; 134 goto exit; 135 } 136 137 mbedtls_x509_crt_init( session->peer_cert ); 138 if( mbedtls_x509_crt_parse( session->peer_cert, entry->peer_cert.p, 139 entry->peer_cert.len ) != 0 ) 140 { 141 mbedtls_free( session->peer_cert ); 142 session->peer_cert = NULL; 143 ret = 1; 144 goto exit; 145 } 146 } 147 #endif /* MBEDTLS_X509_CRT_PARSE_C */ 148 149 ret = 0; 150 goto exit; 151 } 152 153 exit: 154 #if defined(MBEDTLS_THREADING_C) 155 if( mbedtls_mutex_unlock( &cache->mutex ) != 0 ) 156 ret = 1; 157 #endif 158 159 return( ret ); 160 } 161 162 int mbedtls_ssl_cache_set( void *data, const mbedtls_ssl_session *session ) 163 { 164 int ret = 1; 165 #if defined(MBEDTLS_HAVE_TIME) 166 mbedtls_time_t t = mbedtls_time( NULL ), oldest = 0; 167 mbedtls_ssl_cache_entry *old = NULL; 168 #endif 169 mbedtls_ssl_cache_context *cache = (mbedtls_ssl_cache_context *) data; 170 mbedtls_ssl_cache_entry *cur, *prv; 171 int count = 0; 172 173 #if defined(MBEDTLS_THREADING_C) 174 if( ( ret = mbedtls_mutex_lock( &cache->mutex ) ) != 0 ) 175 return( ret ); 176 #endif 177 178 cur = cache->chain; 179 prv = NULL; 180 181 while( cur != NULL ) 182 { 183 count++; 184 185 #if defined(MBEDTLS_HAVE_TIME) 186 if( cache->timeout != 0 && 187 (int) ( t - cur->timestamp ) > cache->timeout ) 188 { 189 cur->timestamp = t; 190 break; /* expired, reuse this slot, update timestamp */ 191 } 192 #endif 193 194 if( memcmp( session->id, cur->session.id, cur->session.id_len ) == 0 ) 195 break; /* client reconnected, keep timestamp for session id */ 196 197 #if defined(MBEDTLS_HAVE_TIME) 198 if( oldest == 0 || cur->timestamp < oldest ) 199 { 200 oldest = cur->timestamp; 201 old = cur; 202 } 203 #endif 204 205 prv = cur; 206 cur = cur->next; 207 } 208 209 if( cur == NULL ) 210 { 211 #if defined(MBEDTLS_HAVE_TIME) 212 /* 213 * Reuse oldest entry if max_entries reached 214 */ 215 if( count >= cache->max_entries ) 216 { 217 if( old == NULL ) 218 { 219 ret = 1; 220 goto exit; 221 } 222 223 cur = old; 224 } 225 #else /* MBEDTLS_HAVE_TIME */ 226 /* 227 * Reuse first entry in chain if max_entries reached, 228 * but move to last place 229 */ 230 if( count >= cache->max_entries ) 231 { 232 if( cache->chain == NULL ) 233 { 234 ret = 1; 235 goto exit; 236 } 237 238 cur = cache->chain; 239 cache->chain = cur->next; 240 cur->next = NULL; 241 prv->next = cur; 242 } 243 #endif /* MBEDTLS_HAVE_TIME */ 244 else 245 { 246 /* 247 * max_entries not reached, create new entry 248 */ 249 cur = mbedtls_calloc( 1, sizeof(mbedtls_ssl_cache_entry) ); 250 if( cur == NULL ) 251 { 252 ret = 1; 253 goto exit; 254 } 255 256 if( prv == NULL ) 257 cache->chain = cur; 258 else 259 prv->next = cur; 260 } 261 262 #if defined(MBEDTLS_HAVE_TIME) 263 cur->timestamp = t; 264 #endif 265 } 266 267 memcpy( &cur->session, session, sizeof( mbedtls_ssl_session ) ); 268 269 #if defined(MBEDTLS_X509_CRT_PARSE_C) 270 /* 271 * If we're reusing an entry, free its certificate first 272 */ 273 if( cur->peer_cert.p != NULL ) 274 { 275 mbedtls_free( cur->peer_cert.p ); 276 memset( &cur->peer_cert, 0, sizeof(mbedtls_x509_buf) ); 277 } 278 279 /* 280 * Store peer certificate 281 */ 282 if( session->peer_cert != NULL ) 283 { 284 cur->peer_cert.p = mbedtls_calloc( 1, session->peer_cert->raw.len ); 285 if( cur->peer_cert.p == NULL ) 286 { 287 ret = 1; 288 goto exit; 289 } 290 291 memcpy( cur->peer_cert.p, session->peer_cert->raw.p, 292 session->peer_cert->raw.len ); 293 cur->peer_cert.len = session->peer_cert->raw.len; 294 295 cur->session.peer_cert = NULL; 296 } 297 #endif /* MBEDTLS_X509_CRT_PARSE_C */ 298 299 ret = 0; 300 301 exit: 302 #if defined(MBEDTLS_THREADING_C) 303 if( mbedtls_mutex_unlock( &cache->mutex ) != 0 ) 304 ret = 1; 305 #endif 306 307 return( ret ); 308 } 309 310 #if defined(MBEDTLS_HAVE_TIME) 311 void mbedtls_ssl_cache_set_timeout( mbedtls_ssl_cache_context *cache, int timeout ) 312 { 313 if( timeout < 0 ) timeout = 0; 314 315 cache->timeout = timeout; 316 } 317 #endif /* MBEDTLS_HAVE_TIME */ 318 319 void mbedtls_ssl_cache_set_max_entries( mbedtls_ssl_cache_context *cache, int max ) 320 { 321 if( max < 0 ) max = 0; 322 323 cache->max_entries = max; 324 } 325 326 void mbedtls_ssl_cache_free( mbedtls_ssl_cache_context *cache ) 327 { 328 mbedtls_ssl_cache_entry *cur, *prv; 329 330 cur = cache->chain; 331 332 while( cur != NULL ) 333 { 334 prv = cur; 335 cur = cur->next; 336 337 mbedtls_ssl_session_free( &prv->session ); 338 339 #if defined(MBEDTLS_X509_CRT_PARSE_C) 340 mbedtls_free( prv->peer_cert.p ); 341 #endif /* MBEDTLS_X509_CRT_PARSE_C */ 342 343 mbedtls_free( prv ); 344 } 345 346 #if defined(MBEDTLS_THREADING_C) 347 mbedtls_mutex_free( &cache->mutex ); 348 #endif 349 cache->chain = NULL; 350 } 351 352 #endif /* MBEDTLS_SSL_CACHE_C */ 353