mbedtls/include/mbedtls/platform_util.h
Andrzej Kurek a138c0a0b0
Move size checks outside of mbedtls_platform_random_in_range
Update the documentation to mention that calling it with zero
as an argument will result in an undefined behavior.
Signed-off-by: Andrzej Kurek <andrzej.kurek@arm.com>
2020-11-12 17:05:51 +01:00

436 lines
16 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 "config.h"
#else
#include MBEDTLS_CONFIG_FILE
#endif
#include <stdint.h>
#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 */
#if defined(__GNUC__) || defined(__arm__)
#define MBEDTLS_ALWAYS_INLINE __attribute__((always_inline))
#else
#define MBEDTLS_ALWAYS_INLINE
#endif
/* 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
*
* \return The value of \p buf if the operation was successful.
* \return NULL if a potential FI attack was detected or input parameters
* are not valid.
*/
void *mbedtls_platform_zeroize( void *buf, size_t len );
/**
* \brief Secure memset
*
* This is a constant-time version of memset(). The buffer is
* initialised with random data and the order is also randomised
* using the RNG in order to further harden against side-channel
* attacks.
*
* \param ptr Buffer to be set.
* \param value Value to be used when setting the buffer.
* \param num The length of the buffer in bytes.
*
* \return The value of \p ptr if the operation was successful.
* \return NULL if a potential FI attack was detected.
*/
void *mbedtls_platform_memset( void *ptr, int value, size_t num );
/**
* \brief Secure memcpy
*
* This is a constant-time version of memcpy(). The buffer is
* initialised with random data and the order is also randomised
* using the RNG in order to further harden against side-channel
* attacks.
*
* \param dst Destination buffer where the data is being copied to.
* \param src Source buffer where the data is being copied from.
* \param num The length of the buffers in bytes.
*
* \return The value of \p dst.
* \return NULL if a potential FI attack was detected.
*/
void *mbedtls_platform_memcpy( void *dst, const void *src, size_t num );
/**
* \brief Secure memmove
*
* This is a constant-time version of memmove(). It is based on
* the double use of the mbedtls_platform_memcpy() function secured
* against side-channel attacks.
*
* \param dst Destination buffer where the data is being moved to.
* \param src Source buffer where the data is being moved from.
* \param num The length of the buffers in bytes.
*
* \return 0 if the operation was successful
* \return #MBEDTLS_ERR_PLATFORM_ALLOC_FAILED if a memory allocation failed
*/
int mbedtls_platform_memmove( void *dst, const void *src, size_t num );
#if !defined(MBEDTLS_DEPRECATED_REMOVED)
#if defined(MBEDTLS_DEPRECATED_WARNING)
#define MBEDTLS_DEPRECATED __attribute__((deprecated))
#else
#define MBEDTLS_DEPRECATED
#endif
/**
* \brief Secure memcmp
*
* This is a constant-time version of memcmp(), but without checking
* if the bytes are greater or lower. The order is also randomised
* using the RNG in order to further harden against side-channel attacks.
*
* \param buf1 First buffer to compare.
* \param buf2 Second buffer to compare against.
* \param num The length of the buffers in bytes.
*
* \deprecated Superseded by mbedtls_platform_memequal(), and is only an alias to it.
*
* \return 0 if the buffers were equal or an unspecified non-zero value
* otherwise.
*/
int mbedtls_platform_memcmp( const void *buf1, const void *buf2, size_t num );
#endif
/**
* \brief Secure check if the buffers have the same data.
*
* This is a constant-time version of memcmp(), but without checking
* if the bytes are greater or lower. The order is also randomised
* using the RNG in order to further harden against side-channel attacks.
*
* \param buf1 First buffer to compare.
* \param buf2 Second buffer to compare against.
* \param num The length of the buffers in bytes.
*
* \return 0 if the buffers were equal or an unspecified non-zero value
* otherwise.
*/
int mbedtls_platform_memequal( const void *buf1, const void *buf2, size_t num );
/**
* \brief RNG-function for getting a random 32-bit integer.
*
* \return The generated random number.
*/
uint32_t mbedtls_platform_random_uint32( void );
/**
* \brief RNG-function for getting a random in given range.
*
* This function is meant to provide a global RNG to be used
* throughout Mbed TLS for hardening the library. It is used
* for generating a random delay, random data or random offset
* for utility functions. It is not meant to be a
* cryptographically secure RNG, but provide an RNG for utility
* functions.
*
* \param num Max-value for the generated random number, exclusive.
* Must be greater than zero, otherwise an undefined behavior
* will occur on "num % 0".
* The generated number will be on range [0, num).
*
* \return The generated random number.
*/
uint32_t mbedtls_platform_random_in_range( uint32_t num );
/**
* \brief Random delay function.
*
* Function implements a random delay by incrementing a local
* variable randomized number of times (busy-looping).
*
* Duration of the delay is random as number of variable increments
* is randomized.
*
* \note This function works only if the MBEDTLS_FI_COUNTERMEASURES flag
* is defined in the configuration. Otherwise, the function does
* nothing.
*/
void mbedtls_platform_random_delay( void );
/**
* \brief RNG-function for getting a random buffer.
*
* \param buf Buffer for random data
* \param len Length of the buffer in bytes
*
*/
void mbedtls_platform_random_buf( uint8_t *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 */
#if defined(MBEDTLS_VALIDATE_AES_KEYS_INTEGRITY) || defined(MBEDTLS_VALIDATE_SSL_KEYS_INTEGRITY)
/**
* \brief Calculate a hash from the given data.
*
* \param data Data from which the hash is calculated.
* \param data_len_bytes Length of the data in bytes.
*
* \return A hash calculated from the provided data.
*/
uint32_t mbedtls_hash( const void *data, size_t data_len_bytes );
#endif
/**
* \brief Convert a 32-bit number to the big endian format and write it to
* the given buffer.
*
* \param buf Address where the converted number is written.
* \param num A number that needs to be converted to the big endian format.
*
* \return Address to the end of buffer where the converted number is
* written.
*/
unsigned char* mbedtls_platform_put_uint32_be( unsigned char *buf,
size_t num );
/**
* \brief Convert a 24-bit number to the big endian format and write it to
* the given buffer.
*
* \param buf Address where the converted number is written.
* \param num A number that needs to be converted to the big endian format.
*
* \return Address to the end of buffer where the converted number is
* written.
*/
unsigned char* mbedtls_platform_put_uint24_be( unsigned char *buf,
size_t num );
/**
* \brief Convert a 16-bit number to the big endian format and write it to
* the given buffer.
*
*
* \param buf Address where the converted number is written.
* \param num A number that needs to be converted to the big endian format.
*
* \return Address to the end of buffer where the converted number is
* written.
*/
unsigned char* mbedtls_platform_put_uint16_be( unsigned char *buf,
size_t num );
/**
* \brief Convert a 32-bit number from the big endian format.
*
* The function reads a 32-bit number from the given buffer in the
* big endian format and returns it to the caller.
*
* \param buf Buffer where the 32-bit number locates.
*
* \return Converted number.
*/
size_t mbedtls_platform_get_uint32_be( const unsigned char *buf );
/**
* \brief Convert a 24-bit number from the big endian format.
*
* The function reads a 14-bit number from the given buffer in the
* big endian format and returns it to the caller.
*
* \param buf Buffer where the 24-bit number locates.
*
* \return Converted number.
*/
size_t mbedtls_platform_get_uint24_be( const unsigned char *buf );
/**
* \brief Convert a 16-bit number from the big endian format.
*
* The function reads a 16-bit number from the given buffer in the
* big endian format and returns it to the caller.
*
* \param buf Buffer where the 16-bit number locates.
*
* \return Converted number.
*/
size_t mbedtls_platform_get_uint16_be( const unsigned char *buf );
#ifdef __cplusplus
}
#endif
#endif /* MBEDTLS_PLATFORM_UTIL_H */