/* | |
* 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) | |
*/ | |
/* | |
* Ensure gmtime_r is available even with -std=c99; must be defined before | |
* config.h, which pulls in glibc's features.h. Harmless on other platforms. | |
*/ | |
#if !defined(_POSIX_C_SOURCE) | |
#define _POSIX_C_SOURCE 200112L | |
#endif | |
#if !defined(MBEDTLS_CONFIG_FILE) | |
#include "mbedtls/config.h" | |
#else | |
#include MBEDTLS_CONFIG_FILE | |
#endif | |
#include "mbedtls/platform_util.h" | |
#include "mbedtls/platform.h" | |
#include "mbedtls/threading.h" | |
#include <stddef.h> | |
#include <string.h> | |
#if !defined(MBEDTLS_PLATFORM_ZEROIZE_ALT) | |
/* | |
* This implementation should never be optimized out by the compiler | |
* | |
* This implementation for mbedtls_platform_zeroize() was inspired from Colin | |
* Percival's blog article at: | |
* | |
* http://www.daemonology.net/blog/2014-09-04-how-to-zero-a-buffer.html | |
* | |
* It uses a volatile function pointer to the standard memset(). Because the | |
* pointer is volatile the compiler expects it to change at | |
* any time and will not optimize out the call that could potentially perform | |
* other operations on the input buffer instead of just setting it to 0. | |
* Nevertheless, as pointed out by davidtgoldblatt on Hacker News | |
* (refer to http://www.daemonology.net/blog/2014-09-05-erratum.html for | |
* details), optimizations of the following form are still possible: | |
* | |
* if( memset_func != memset ) | |
* memset_func( buf, 0, len ); | |
* | |
* Note that it is extremely difficult to guarantee that | |
* mbedtls_platform_zeroize() will not be optimized out by aggressive compilers | |
* in a portable way. For this reason, Mbed TLS also 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. | |
*/ | |
static void * (* const volatile memset_func)( void *, int, size_t ) = memset; | |
void mbedtls_platform_zeroize( void *buf, size_t len ) | |
{ | |
memset_func( buf, 0, len ); | |
} | |
#endif /* MBEDTLS_PLATFORM_ZEROIZE_ALT */ | |
#if defined(MBEDTLS_HAVE_TIME_DATE) && !defined(MBEDTLS_PLATFORM_GMTIME_R_ALT) | |
#include <time.h> | |
#if !defined(_WIN32) && (defined(unix) || \ | |
defined(__unix) || defined(__unix__) || (defined(__APPLE__) && \ | |
defined(__MACH__))) | |
#include <unistd.h> | |
#endif /* !_WIN32 && (unix || __unix || __unix__ || | |
* (__APPLE__ && __MACH__)) */ | |
#if !( ( defined(_POSIX_VERSION) && _POSIX_VERSION >= 200809L ) || \ | |
( defined(_POSIX_THREAD_SAFE_FUNCTIONS ) && \ | |
_POSIX_THREAD_SAFE_FUNCTIONS >= 20112L ) ) | |
/* | |
* This is a convenience shorthand macro to avoid checking the long | |
* preprocessor conditions above. Ideally, we could expose this macro in | |
* platform_util.h and simply use it in platform_util.c, threading.c and | |
* threading.h. However, this macro is not part of the Mbed TLS public API, so | |
* we keep it private by only defining it in this file | |
*/ | |
#if ! ( defined(_WIN32) && !defined(EFIX64) && !defined(EFI32) ) | |
#define PLATFORM_UTIL_USE_GMTIME | |
#endif /* ! ( defined(_WIN32) && !defined(EFIX64) && !defined(EFI32) ) */ | |
#endif /* !( ( defined(_POSIX_VERSION) && _POSIX_VERSION >= 200809L ) || \ | |
( defined(_POSIX_THREAD_SAFE_FUNCTIONS ) && \ | |
_POSIX_THREAD_SAFE_FUNCTIONS >= 20112L ) ) */ | |
struct tm *mbedtls_platform_gmtime_r( const mbedtls_time_t *tt, | |
struct tm *tm_buf ) | |
{ | |
#if defined(_WIN32) && !defined(EFIX64) && !defined(EFI32) | |
return( ( gmtime_s( tm_buf, tt ) == 0 ) ? tm_buf : NULL ); | |
#elif !defined(PLATFORM_UTIL_USE_GMTIME) | |
return( gmtime_r( tt, tm_buf ) ); | |
#else | |
struct tm *lt; | |
#if defined(MBEDTLS_THREADING_C) | |
if( mbedtls_mutex_lock( &mbedtls_threading_gmtime_mutex ) != 0 ) | |
return( NULL ); | |
#endif /* MBEDTLS_THREADING_C */ | |
lt = gmtime( tt ); | |
if( lt != NULL ) | |
{ | |
memcpy( tm_buf, lt, sizeof( struct tm ) ); | |
} | |
#if defined(MBEDTLS_THREADING_C) | |
if( mbedtls_mutex_unlock( &mbedtls_threading_gmtime_mutex ) != 0 ) | |
return( NULL ); | |
#endif /* MBEDTLS_THREADING_C */ | |
return( ( lt == NULL ) ? NULL : tm_buf ); | |
#endif /* _WIN32 && !EFIX64 && !EFI32 */ | |
} | |
#endif /* MBEDTLS_HAVE_TIME_DATE && MBEDTLS_PLATFORM_GMTIME_R_ALT */ |