mirror of
https://github.com/yuzu-emu/mbedtls.git
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61 lines
2.1 KiB
C
61 lines
2.1 KiB
C
/*
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* mbed TLS utility functions
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*
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* Copyright (C) 2017, ARM Limited, All Rights Reserved
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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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* This file is part of mbed TLS (https://tls.mbed.org)
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*/
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#if !defined(MBEDTLS_CONFIG_FILE)
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#include "mbedtls/config.h"
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#else
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#include MBEDTLS_CONFIG_FILE
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#endif
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#include "mbedtls/utils.h"
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#include <stddef.h>
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#include <string.h>
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#if !defined(MBEDTLS_UTILS_ZEROIZE_ALT)
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/*
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* This implementation should never be optimized out by the compiler
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*
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* This implementation for mbedtls_zeroize() uses a volatile function pointer.
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* We always know that it points to memset(), but because it is volatile the
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* compiler expects it to change at any time and will not optimize out the
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* call that could potentially perform other operations on the input buffer
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* instead of just setting it to 0. Nevertheless, optimizations of the
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* following form are still possible:
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*
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* if( memset_func != memset )
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* memset_func( buf, 0, len );
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*
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* Note that it is extremely difficult to guarantee that mbedtls_zeroize()
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* will not be optimized out by aggressive compilers in a portable way. For
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* this reason, mbed TLS also provides the configuration option
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* MBEDTLS_UTILS_ZEROIZE_ALT, which allows users to configure
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* mbedtls_zeroize() to use a suitable implementation for their platform and
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* needs.
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*/
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static void * (* const volatile memset_func)( void *, int, size_t ) = memset;
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void mbedtls_zeroize( void *buf, size_t len )
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{
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memset_func( buf, 0, len );
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}
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#endif /* MBEDTLS_UTILS_ZEROIZE_ALT */
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