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Make utils module part of the platform

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This commit is contained in:
Andres Amaya Garcia 2018-04-17 09:16:30 -05:00
parent ae8e306973
commit 904e1efb8c
4 changed files with 38 additions and 26 deletions
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66
library/utils.c
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@ -1,66 +0,0 @@
/*
* Mbed TLS utility functions
*
* 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/utils.h"
#include <stddef.h>
#include <string.h>
#if !defined(MBEDTLS_UTILS_ZEROIZE_ALT)
/*
* This implementation should never be optimized out by the compiler
*
* This implementation for mbedtls_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_zeroize()
* will not be optimized out by aggressive compilers in a portable way. For
* this reason, Mbed TLS also provides the configuration option
* MBEDTLS_UTILS_ZEROIZE_ALT, which allows users to configure
* mbedtls_zeroize() to use a suitable implementation for their platform and
* needs.
*/
static void * (* const volatile memset_func)( void *, int, size_t ) = memset;
void mbedtls_zeroize( void *buf, size_t len )
{
memset_func( buf, 0, len );
}
#endif /* MBEDTLS_UTILS_ZEROIZE_ALT */