platform_util.h

/**
 * \file platform_util.h
 *
 * \brief 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)
 */
#ifndef MBEDTLS_PLATFORM_UTIL_H
#define MBEDTLS_PLATFORM_UTIL_H

#include <stddef.h>

#ifdef __cplusplus
extern "C" {
#endif


/* Internal macros meant to be called only from within the library. */
#define MBEDTLS_INTERNAL_VALIDATE_RET( cond, ret )  do { } while( 0 )
#define MBEDTLS_INTERNAL_VALIDATE( cond )           do { } while( 0 )

/**
 * \brief       Securely zeroize a buffer
 *
 *              The function is meant to wipe the data contained in a buffer so
 *              that it can no longer be recovered even if the program memory
 *              is later compromised. Call this function on sensitive data
 *              stored on the stack before returning from a function, and on
 *              sensitive data stored on the heap before freeing the heap
 *              object.
 *
 *              It is extremely difficult to guarantee that calls to
 *              mbedtls_platform_zeroize() are not removed by aggressive
 *              compiler optimizations in a portable way. For this reason, Mbed
 *              TLS 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
 *
 * \param buf   Buffer to be zeroized
 * \param len   Length of the buffer in bytes
 *
 */
void mbedtls_platform_zeroize( void *buf, size_t len );


#ifdef __cplusplus
}
#endif

#endif /* MBEDTLS_PLATFORM_UTIL_H */