/**
* \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: GPL-2.0
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License along
* with this program; if not, write to the Free Software Foundation, Inc.,
* 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
*
* This file is part of Mbed TLS (https://tls.mbed.org)
*/
#ifndef MBEDTLS_PLATFORM_UTIL_H
#define MBEDTLS_PLATFORM_UTIL_H
#if !defined(MBEDTLS_CONFIG_FILE)
#include "config.h"
#else
#include MBEDTLS_CONFIG_FILE
#endif
#include <stddef.h>
#if defined(MBEDTLS_HAVE_TIME_DATE)
#include "platform_time.h"
#include <time.h>
#endif /* MBEDTLS_HAVE_TIME_DATE */
#ifdef __cplusplus
extern "C" {
#endif
#if defined(MBEDTLS_CHECK_PARAMS)
#if defined(MBEDTLS_CHECK_PARAMS_ASSERT)
/* Allow the user to define MBEDTLS_PARAM_FAILED to something like assert
* (which is what our config.h suggests). */
#include <assert.h>
#endif /* MBEDTLS_CHECK_PARAMS_ASSERT */
#if defined(MBEDTLS_PARAM_FAILED)
/** An alternative definition of MBEDTLS_PARAM_FAILED has been set in config.h.
*
* This flag can be used to check whether it is safe to assume that
* MBEDTLS_PARAM_FAILED() will expand to a call to mbedtls_param_failed().
*/
#define MBEDTLS_PARAM_FAILED_ALT
#elif defined(MBEDTLS_CHECK_PARAMS_ASSERT)
#define MBEDTLS_PARAM_FAILED( cond ) assert( cond )
#define MBEDTLS_PARAM_FAILED_ALT
#else /* MBEDTLS_PARAM_FAILED */
#define MBEDTLS_PARAM_FAILED( cond ) \
mbedtls_param_failed( #cond, __FILE__, __LINE__ )
/**
* \brief User supplied callback function for parameter validation failure.
* See #MBEDTLS_CHECK_PARAMS for context.
*
* This function will be called unless an alternative treatement
* is defined through the #MBEDTLS_PARAM_FAILED macro.
*
* This function can return, and the operation will be aborted, or
* alternatively, through use of setjmp()/longjmp() can resume
* execution in the application code.
*
* \param failure_condition The assertion that didn't hold.
* \param file The file where the assertion failed.
* \param line The line in the file where the assertion failed.
*/
void mbedtls_param_failed( const char *failure_condition,
const char *file,
int line );
#endif /* MBEDTLS_PARAM_FAILED */
/* Internal macro meant to be called only from within the library. */
#define MBEDTLS_INTERNAL_VALIDATE_RET( cond, ret ) \
do { \
if( !(cond) ) \
{ \
MBEDTLS_PARAM_FAILED( cond ); \
return( ret ); \
} \
} while( 0 )
/* Internal macro meant to be called only from within the library. */
#define MBEDTLS_INTERNAL_VALIDATE( cond ) \
do { \
if( !(cond) ) \
{ \
MBEDTLS_PARAM_FAILED( cond ); \
return; \
} \
} while( 0 )
#else /* MBEDTLS_CHECK_PARAMS */
/* 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 )
#endif /* MBEDTLS_CHECK_PARAMS */
/* Internal helper macros for deprecating API constants. */
#if !defined(MBEDTLS_DEPRECATED_REMOVED)
#if defined(MBEDTLS_DEPRECATED_WARNING)
/* Deliberately don't (yet) export MBEDTLS_DEPRECATED here
* to avoid conflict with other headers which define and use
* it, too. We might want to move all these definitions here at
* some point for uniformity. */
#define MBEDTLS_DEPRECATED __attribute__((deprecated))
MBEDTLS_DEPRECATED typedef char const * mbedtls_deprecated_string_constant_t;
#define MBEDTLS_DEPRECATED_STRING_CONSTANT( VAL ) \
( (mbedtls_deprecated_string_constant_t) ( VAL ) )
MBEDTLS_DEPRECATED typedef int mbedtls_deprecated_numeric_constant_t;
#define MBEDTLS_DEPRECATED_NUMERIC_CONSTANT( VAL ) \
( (mbedtls_deprecated_numeric_constant_t) ( VAL ) )
#undef MBEDTLS_DEPRECATED
#else /* MBEDTLS_DEPRECATED_WARNING */
#define MBEDTLS_DEPRECATED_STRING_CONSTANT( VAL ) VAL
#define MBEDTLS_DEPRECATED_NUMERIC_CONSTANT( VAL ) VAL
#endif /* MBEDTLS_DEPRECATED_WARNING */
#endif /* MBEDTLS_DEPRECATED_REMOVED */
/**
* \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 );
#if defined(MBEDTLS_HAVE_TIME_DATE)
/**
* \brief Platform-specific implementation of gmtime_r()
*
* The function is a thread-safe abstraction that behaves
* similarly to the gmtime_r() function from Unix/POSIX.
*
* Mbed TLS will try to identify the underlying platform and
* make use of an appropriate underlying implementation (e.g.
* gmtime_r() for POSIX and gmtime_s() for Windows). If this is
* not possible, then gmtime() will be used. In this case, calls
* from the library to gmtime() will be guarded by the mutex
* mbedtls_threading_gmtime_mutex if MBEDTLS_THREADING_C is
* enabled. It is recommended that calls from outside the library
* are also guarded by this mutex.
*
* If MBEDTLS_PLATFORM_GMTIME_R_ALT is defined, then Mbed TLS will
* unconditionally use the alternative implementation for
* mbedtls_platform_gmtime_r() supplied by the user at compile time.
*
* \param tt Pointer to an object containing time (in seconds) since the
* epoch to be converted
* \param tm_buf Pointer to an object where the results will be stored
*
* \return Pointer to an object of type struct tm on success, otherwise
* NULL
*/
struct tm *mbedtls_platform_gmtime_r( const mbedtls_time_t *tt,
struct tm *tm_buf );
#endif /* MBEDTLS_HAVE_TIME_DATE */
#ifdef __cplusplus
}
#endif
#endif /* MBEDTLS_PLATFORM_UTIL_H */