mirror of
https://github.com/yuzu-emu/mbedtls
synced 2024-11-24 13:58:13 +00:00
67 lines
2.4 KiB
C
67 lines
2.4 KiB
C
/*
|
|
* Common and shared functions used by multiple modules in the Mbed TLS
|
|
* library.
|
|
*
|
|
* Copyright (C) 2018, Arm Limited, All Rights Reserved
|
|
* 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.
|
|
*
|
|
* This file is part of Mbed TLS (https://tls.mbed.org)
|
|
*/
|
|
|
|
#if !defined(MBEDTLS_CONFIG_FILE)
|
|
#include "mbedtls/config.h"
|
|
#else
|
|
#include MBEDTLS_CONFIG_FILE
|
|
#endif
|
|
|
|
#include "mbedtls/platform_util.h"
|
|
|
|
#include <stddef.h>
|
|
#include <string.h>
|
|
|
|
#if !defined(MBEDTLS_PLATFORM_ZEROIZE_ALT)
|
|
/*
|
|
* This implementation should never be optimized out by the compiler
|
|
*
|
|
* This implementation for mbedtls_platform_zeroize() was inspired from Colin
|
|
* Percival's blog article at:
|
|
*
|
|
* http://www.daemonology.net/blog/2014-09-04-how-to-zero-a-buffer.html
|
|
*
|
|
* It uses a volatile function pointer to the standard memset(). Because the
|
|
* pointer is volatile the compiler expects it to change at
|
|
* any time and will not optimize out the call that could potentially perform
|
|
* other operations on the input buffer instead of just setting it to 0.
|
|
* Nevertheless, as pointed out by davidtgoldblatt on Hacker News
|
|
* (refer to http://www.daemonology.net/blog/2014-09-05-erratum.html for
|
|
* details), optimizations of the following form are still possible:
|
|
*
|
|
* if( memset_func != memset )
|
|
* memset_func( buf, 0, len );
|
|
*
|
|
* Note that it is extremely difficult to guarantee that
|
|
* mbedtls_platform_zeroize() will not be optimized out by aggressive compilers
|
|
* in a portable way. For this reason, Mbed TLS also provides the configuration
|
|
* option MBEDTLS_PLATFORM_ZEROIZE_ALT, which allows users to configure
|
|
* mbedtls_platform_zeroize() to use a suitable implementation for their
|
|
* platform and needs.
|
|
*/
|
|
static void * (* const volatile memset_func)( void *, int, size_t ) = memset;
|
|
|
|
void mbedtls_platform_zeroize( void *buf, size_t len )
|
|
{
|
|
memset_func( buf, 0, len );
|
|
}
|
|
#endif /* MBEDTLS_PLATFORM_ZEROIZE_ALT */
|