mbedtls/include/mbedtls/platform_util.h
Hanno Becker 6d0816a8ae Introduce macros to deprecate constants in the API
This commit introduces macros

* MBEDTLS_DEPRECATED_STRING_CONSTANT
* MBEDTLS_DEPRECATED_NUMERIC_CONSTANT

to platform_util.h which can be used to deprecate public macro constants.

Their definition is essentially taken from dhm.h where the
MBEDTLS_DEPRECATED_STRING_CONSTANT was used to deprecate
insecure hardcoded DHM primes.
2018-12-17 11:39:38 +00:00

124 lines
4.7 KiB
C

/**
* \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
#if !defined(MBEDTLS_CONFIG_FILE)
#include "mbedtls/config.h"
#else
#include MBEDTLS_CONFIG_FILE
#endif
#include <stddef.h>
#if defined(MBEDTLS_HAVE_TIME_DATE)
#include "mbedtls/platform_time.h"
#include <time.h>
#endif /* MBEDTLS_HAVE_TIME_DATE */
#ifdef __cplusplus
extern "C" {
#endif
/* Internal helper macros for deprecating API constants. */
#if !defined(MBEDTLS_DEPRECATED_REMOVED)
#if defined(MBEDTLS_DEPRECATED_WARNING)
/* Deliberately don't (yet) define 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. */
__attribute__((deprecated))
typedef char const * mbedtls_deprecated_string_constant_t;
#define MBEDTLS_DEPRECATED_STRING_CONSTANT( VAL ) \
( (mbedtls_deprecated_string_constant_t) ( VAL ) )
__attribute__((deprecated))
typedef int mbedtls_deprecated_numeric_constant_t;
#define MBEDTLS_DEPRECATED_NUMERIC_CONSTANT( VAL ) \
( (mbedtls_deprecated_numeric_constant_t) ( VAL ) )
#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 */