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