mbedtls/library/platform_util.c

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/*
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* 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.
*/
/*
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* Ensure gmtime_r is available even with -std=c99; must be defined before
* mbedtls_config.h, which pulls in glibc's features.h. Harmless on other platforms.
*/
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#if !defined(_POSIX_C_SOURCE)
#define _POSIX_C_SOURCE 200112L
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#endif
#include "common.h"
#include "mbedtls/platform_util.h"
#include "mbedtls/platform.h"
#include "mbedtls/threading.h"
#include <stddef.h>
#include <string.h>
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#if !defined(MBEDTLS_PLATFORM_ZEROIZE_ALT)
/*
* This implementation should never be optimized out by the compiler
*
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* 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 );
*
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* 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);
}
}
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#endif /* MBEDTLS_PLATFORM_ZEROIZE_ALT */
#if defined(MBEDTLS_HAVE_TIME_DATE) && !defined(MBEDTLS_PLATFORM_GMTIME_R_ALT)
#define __STDC_WANT_LIB_EXT1__ 1 /* Ask for the C11 gmtime_s() if it's available */
#include <time.h>
#if !defined(_WIN32) && (defined(unix) || \
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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))
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/*
* 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
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* 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
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*/
#if !(defined(_WIN32) && !defined(EFIX64) && !defined(EFI32)) || \
(defined(__MINGW32__) && !defined(__MINGW64_VERSION_MAJOR))
#define PLATFORM_UTIL_USE_GMTIME
#endif
#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(PLATFORM_UTIL_USE_GMTIME)
#if defined(__STDC_LIB_EXT1__)
return (gmtime_s(tt, tm_buf) == 0) ? NULL : tm_buf;
#else
/* MSVC and mingw64 argument order and return value are inconsistent with the C11 standard */
return (gmtime_s(tm_buf, tt) == 0) ? tm_buf : NULL;
#endif
#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 */
#if defined(MBEDTLS_TEST_HOOKS)
void (*mbedtls_test_hook_test_fail)(const char *, int, const char *);
#endif /* MBEDTLS_TEST_HOOKS */
/*
* Provide external definitions of some inline functions so that the compiler
* has the option to not inline them
*/
extern inline void mbedtls_xor(unsigned char *r,
const unsigned char *a,
const unsigned char *b,
size_t n);
extern inline uint16_t mbedtls_get_unaligned_uint16(const void *p);
extern inline void mbedtls_put_unaligned_uint16(void *p, uint16_t x);
extern inline uint32_t mbedtls_get_unaligned_uint32(const void *p);
extern inline void mbedtls_put_unaligned_uint32(void *p, uint32_t x);
extern inline uint64_t mbedtls_get_unaligned_uint64(const void *p);
extern inline void mbedtls_put_unaligned_uint64(void *p, uint64_t x);
#if defined(MBEDTLS_HAVE_TIME) && !defined(MBEDTLS_PLATFORM_MS_TIME_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 >= 199309L)
mbedtls_ms_time_t mbedtls_ms_time(void)
{
int ret;
struct timespec tv;
mbedtls_ms_time_t current_ms;
ret = clock_gettime(CLOCK_REALTIME, &tv);
if (ret) {
return 0;
}
current_ms = tv.tv_sec;
return current_ms*1000 + tv.tv_nsec / 1000000;
}
#elif defined(_WIN32) || defined(WIN32) || defined(__CYGWIN__) || \
defined(__MINGW32__) || defined(_WIN64)
#include <windows.h>
mbedtls_ms_time_t mbedtls_ms_time(void)
{
FILETIME ct;
mbedtls_ms_time_t current_ms;
GetSystemTimeAsFileTime(&ct);
current_ms = ((mbedtls_ms_time_t) ct.dwLowDateTime +
((mbedtls_ms_time_t) (ct.dwHighDateTime) << 32LL))/10;
return current_ms;
}
#else
#error "No mbedtls_ms_time available"
#endif
#endif /* MBEDTLS_HAVE_TIME && !MBEDTLS_PLATFORM_MS_TIME_ALT */