139 lines
4.8 KiB
C
139 lines
4.8 KiB
C
/*
|
|
* Common and shared functions used by multiple modules in the Mbed TLS
|
|
* library.
|
|
*
|
|
* Copyright The Mbed TLS Contributors
|
|
* 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.
|
|
*/
|
|
|
|
/*
|
|
* 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
|
|
|
|
#include "common.h"
|
|
|
|
#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)
|
|
{
|
|
MBEDTLS_INTERNAL_VALIDATE(len == 0 || buf != NULL);
|
|
|
|
if (len > 0) {
|
|
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 >= 200112L))
|
|
/*
|
|
* 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 >= 200112L ) ) */
|
|
|
|
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 */
|