/* * SSL session cache implementation * * Copyright The Mbed TLS Contributors * SPDX-License-Identifier: Apache-2.0 * * Licensed under the Apache License, Version 2.0 (the "License"); you may * not use this file except in compliance with the License. * You may obtain a copy of the License at * * http://www.apache.org/licenses/LICENSE-2.0 * * Unless required by applicable law or agreed to in writing, software * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. * See the License for the specific language governing permissions and * limitations under the License. */ /* * These session callbacks use a simple chained list * to store and retrieve the session information. */ #include "common.h" #if defined(MBEDTLS_SSL_CACHE_C) #if defined(MBEDTLS_PLATFORM_C) #include "mbedtls/platform.h" #else #include <stdlib.h> #define mbedtls_calloc calloc #define mbedtls_free free #endif #include "mbedtls/ssl_cache.h" #include "mbedtls/ssl_internal.h" #include <string.h> void mbedtls_ssl_cache_init( mbedtls_ssl_cache_context *cache ) { memset( cache, 0, sizeof( mbedtls_ssl_cache_context ) ); cache->timeout = MBEDTLS_SSL_CACHE_DEFAULT_TIMEOUT; cache->max_entries = MBEDTLS_SSL_CACHE_DEFAULT_MAX_ENTRIES; #if defined(MBEDTLS_THREADING_C) mbedtls_mutex_init( &cache->mutex ); #endif } int mbedtls_ssl_cache_get( void *data, mbedtls_ssl_session *session ) { int ret = 1; #if defined(MBEDTLS_HAVE_TIME) mbedtls_time_t t = mbedtls_time( NULL ); #endif mbedtls_ssl_cache_context *cache = (mbedtls_ssl_cache_context *) data; mbedtls_ssl_cache_entry *cur, *entry; #if defined(MBEDTLS_THREADING_C) if( mbedtls_mutex_lock( &cache->mutex ) != 0 ) return( 1 ); #endif cur = cache->chain; entry = NULL; while( cur != NULL ) { entry = cur; cur = cur->next; #if defined(MBEDTLS_HAVE_TIME) if( cache->timeout != 0 && (int) ( t - entry->timestamp ) > cache->timeout ) continue; #endif if( session->id_len != entry->session.id_len || memcmp( session->id, entry->session.id, entry->session.id_len ) != 0 ) { continue; } ret = mbedtls_ssl_session_copy( session, &entry->session ); if( ret != 0 ) { ret = 1; goto exit; } #if defined(MBEDTLS_X509_CRT_PARSE_C) && \ defined(MBEDTLS_SSL_KEEP_PEER_CERTIFICATE) /* * Restore peer certificate (without rest of the original chain) */ if( entry->peer_cert.p != NULL ) { /* `session->peer_cert` is NULL after the call to * mbedtls_ssl_session_copy(), because cache entries * have the `peer_cert` field set to NULL. */ if( ( session->peer_cert = mbedtls_calloc( 1, sizeof(mbedtls_x509_crt) ) ) == NULL ) { ret = 1; goto exit; } mbedtls_x509_crt_init( session->peer_cert ); if( mbedtls_x509_crt_parse( session->peer_cert, entry->peer_cert.p, entry->peer_cert.len ) != 0 ) { mbedtls_free( session->peer_cert ); session->peer_cert = NULL; ret = 1; goto exit; } } #endif /* MBEDTLS_X509_CRT_PARSE_C && MBEDTLS_SSL_KEEP_PEER_CERTIFICATE */ ret = 0; goto exit; } exit: #if defined(MBEDTLS_THREADING_C) if( mbedtls_mutex_unlock( &cache->mutex ) != 0 ) ret = 1; #endif return( ret ); } int mbedtls_ssl_cache_set( void *data, const mbedtls_ssl_session *session ) { int ret = 1; #if defined(MBEDTLS_HAVE_TIME) mbedtls_time_t t = mbedtls_time( NULL ), oldest = 0; mbedtls_ssl_cache_entry *old = NULL; #endif mbedtls_ssl_cache_context *cache = (mbedtls_ssl_cache_context *) data; mbedtls_ssl_cache_entry *cur, *prv; int count = 0; #if defined(MBEDTLS_THREADING_C) if( ( ret = mbedtls_mutex_lock( &cache->mutex ) ) != 0 ) return( ret ); #endif cur = cache->chain; prv = NULL; while( cur != NULL ) { count++; #if defined(MBEDTLS_HAVE_TIME) if( cache->timeout != 0 && (int) ( t - cur->timestamp ) > cache->timeout ) { cur->timestamp = t; break; /* expired, reuse this slot, update timestamp */ } #endif if( memcmp( session->id, cur->session.id, cur->session.id_len ) == 0 ) break; /* client reconnected, keep timestamp for session id */ #if defined(MBEDTLS_HAVE_TIME) if( oldest == 0 || cur->timestamp < oldest ) { oldest = cur->timestamp; old = cur; } #endif prv = cur; cur = cur->next; } if( cur == NULL ) { #if defined(MBEDTLS_HAVE_TIME) /* * Reuse oldest entry if max_entries reached */ if( count >= cache->max_entries ) { if( old == NULL ) { ret = 1; goto exit; } cur = old; } #else /* MBEDTLS_HAVE_TIME */ /* * Reuse first entry in chain if max_entries reached, * but move to last place */ if( count >= cache->max_entries ) { if( cache->chain == NULL ) { ret = 1; goto exit; } cur = cache->chain; cache->chain = cur->next; cur->next = NULL; prv->next = cur; } #endif /* MBEDTLS_HAVE_TIME */ else { /* * max_entries not reached, create new entry */ cur = mbedtls_calloc( 1, sizeof(mbedtls_ssl_cache_entry) ); if( cur == NULL ) { ret = 1; goto exit; } if( prv == NULL ) cache->chain = cur; else prv->next = cur; } #if defined(MBEDTLS_HAVE_TIME) cur->timestamp = t; #endif } #if defined(MBEDTLS_X509_CRT_PARSE_C) && \ defined(MBEDTLS_SSL_KEEP_PEER_CERTIFICATE) /* * If we're reusing an entry, free its certificate first */ if( cur->peer_cert.p != NULL ) { mbedtls_free( cur->peer_cert.p ); memset( &cur->peer_cert, 0, sizeof(mbedtls_x509_buf) ); } #endif /* MBEDTLS_X509_CRT_PARSE_C && MBEDTLS_SSL_KEEP_PEER_CERTIFICATE */ /* Copy the entire session; this temporarily makes a copy of the * X.509 CRT structure even though we only want to store the raw CRT. * This inefficiency will go away as soon as we implement on-demand * parsing of CRTs, in which case there's no need for the `peer_cert` * field anymore in the first place, and we're done after this call. */ ret = mbedtls_ssl_session_copy( &cur->session, session ); if( ret != 0 ) { ret = 1; goto exit; } #if defined(MBEDTLS_X509_CRT_PARSE_C) && \ defined(MBEDTLS_SSL_KEEP_PEER_CERTIFICATE) /* If present, free the X.509 structure and only store the raw CRT data. */ if( cur->session.peer_cert != NULL ) { cur->peer_cert.p = mbedtls_calloc( 1, cur->session.peer_cert->raw.len ); if( cur->peer_cert.p == NULL ) { ret = 1; goto exit; } memcpy( cur->peer_cert.p, cur->session.peer_cert->raw.p, cur->session.peer_cert->raw.len ); cur->peer_cert.len = session->peer_cert->raw.len; mbedtls_x509_crt_free( cur->session.peer_cert ); mbedtls_free( cur->session.peer_cert ); cur->session.peer_cert = NULL; } #endif /* MBEDTLS_X509_CRT_PARSE_C && MBEDTLS_SSL_KEEP_PEER_CERTIFICATE */ ret = 0; exit: #if defined(MBEDTLS_THREADING_C) if( mbedtls_mutex_unlock( &cache->mutex ) != 0 ) ret = 1; #endif return( ret ); } #if defined(MBEDTLS_HAVE_TIME) void mbedtls_ssl_cache_set_timeout( mbedtls_ssl_cache_context *cache, int timeout ) { if( timeout < 0 ) timeout = 0; cache->timeout = timeout; } #endif /* MBEDTLS_HAVE_TIME */ void mbedtls_ssl_cache_set_max_entries( mbedtls_ssl_cache_context *cache, int max ) { if( max < 0 ) max = 0; cache->max_entries = max; } void mbedtls_ssl_cache_free( mbedtls_ssl_cache_context *cache ) { mbedtls_ssl_cache_entry *cur, *prv; cur = cache->chain; while( cur != NULL ) { prv = cur; cur = cur->next; mbedtls_ssl_session_free( &prv->session ); #if defined(MBEDTLS_X509_CRT_PARSE_C) && \ defined(MBEDTLS_SSL_KEEP_PEER_CERTIFICATE) mbedtls_free( prv->peer_cert.p ); #endif /* MBEDTLS_X509_CRT_PARSE_C && MBEDTLS_SSL_KEEP_PEER_CERTIFICATE */ mbedtls_free( prv ); } #if defined(MBEDTLS_THREADING_C) mbedtls_mutex_free( &cache->mutex ); #endif cache->chain = NULL; } #endif /* MBEDTLS_SSL_CACHE_C */