/* * Common and shared functions used by multiple modules in the Mbed TLS * library. * * Copyright The Mbed TLS Contributors * SPDX-License-Identifier: Apache-2.0 OR GPL-2.0-or-later */ /* * 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 * except OpenBSD, where it stops us accessing explicit_bzero. */ #if !defined(_POSIX_C_SOURCE) && !defined(__OpenBSD__) #define _POSIX_C_SOURCE 200112L #endif #if !defined(_GNU_SOURCE) /* Clang requires this to get support for explicit_bzero */ #define _GNU_SOURCE #endif #include "common.h" #include "mbedtls/platform_util.h" #include "mbedtls/platform.h" #include "mbedtls/threading.h" #include #ifndef __STDC_WANT_LIB_EXT1__ #define __STDC_WANT_LIB_EXT1__ 1 /* Ask for the C11 gmtime_s() and memset_s() if available */ #endif #include #if defined(_WIN32) #include #endif // Detect platforms known to support explicit_bzero() #if defined(__GLIBC__) && (__GLIBC__ >= 2) && (__GLIBC_MINOR__ >= 25) #define MBEDTLS_PLATFORM_HAS_EXPLICIT_BZERO 1 #elif (defined(__FreeBSD__) && (__FreeBSD_version >= 1100037)) || defined(__OpenBSD__) #define MBEDTLS_PLATFORM_HAS_EXPLICIT_BZERO 1 #endif #if !defined(MBEDTLS_PLATFORM_ZEROIZE_ALT) #undef HAVE_MEMORY_SANITIZER #if defined(__has_feature) #if __has_feature(memory_sanitizer) #include #define HAVE_MEMORY_SANITIZER #endif #endif /* * Where possible, we try to detect the presence of a platform-provided * secure memset, such as explicit_bzero(), that is safe against being optimized * out, and use that. * * For other platforms, we provide an implementation that aims not to 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 * the memset() call 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. */ #if !defined(MBEDTLS_PLATFORM_HAS_EXPLICIT_BZERO) && !(defined(__STDC_LIB_EXT1__) && \ !defined(__IAR_SYSTEMS_ICC__)) \ && !defined(_WIN32) static void *(*const volatile memset_func)(void *, int, size_t) = memset; #endif void mbedtls_platform_zeroize(void *buf, size_t len) { if (len > 0) { #if defined(MBEDTLS_PLATFORM_HAS_EXPLICIT_BZERO) explicit_bzero(buf, len); #if defined(HAVE_MEMORY_SANITIZER) /* You'd think that Msan would recognize explicit_bzero() as * equivalent to bzero(), but it actually doesn't on several * platforms, including Linux (Ubuntu 20.04). * https://github.com/google/sanitizers/issues/1507 * https://github.com/openssh/openssh-portable/commit/74433a19bb6f4cef607680fa4d1d7d81ca3826aa */ __msan_unpoison(buf, len); #endif #elif defined(__STDC_LIB_EXT1__) && !defined(__IAR_SYSTEMS_ICC__) memset_s(buf, len, 0, len); #elif defined(_WIN32) SecureZeroMemory(buf, len); #else memset_func(buf, 0, len); #endif #if defined(__GNUC__) /* For clang and recent gcc, pretend that we have some assembly that reads the * zero'd memory as an additional protection against being optimised away. */ #if defined(__clang__) || (__GNUC__ >= 10) #if defined(__clang__) #pragma clang diagnostic push #pragma clang diagnostic ignored "-Wvla" #elif defined(MBEDTLS_COMPILER_IS_GCC) #pragma GCC diagnostic push #pragma GCC diagnostic ignored "-Wvla" #endif asm volatile ("" : : "m" (*(char (*)[len]) buf) :); #if defined(__clang__) #pragma clang diagnostic pop #elif defined(MBEDTLS_COMPILER_IS_GCC) #pragma GCC diagnostic pop #endif #endif #endif } } #endif /* MBEDTLS_PLATFORM_ZEROIZE_ALT */ void mbedtls_zeroize_and_free(void *buf, size_t len) { if (buf != NULL) { mbedtls_platform_zeroize(buf, len); } mbedtls_free(buf); } #if defined(MBEDTLS_HAVE_TIME_DATE) && !defined(MBEDTLS_PLATFORM_GMTIME_R_ALT) #include #if !defined(_WIN32) && (defined(unix) || \ defined(__unix) || defined(__unix__) || (defined(__APPLE__) && \ defined(__MACH__)) || defined__midipix__) #include #endif /* !_WIN32 && (unix || __unix || __unix__ || * (__APPLE__ && __MACH__) || __midipix__) */ #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)) || \ (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 */ #if defined(MBEDTLS_HAVE_TIME) && !defined(MBEDTLS_PLATFORM_MS_TIME_ALT) #include #if !defined(_WIN32) && \ (defined(unix) || defined(__unix) || defined(__unix__) || \ (defined(__APPLE__) && defined(__MACH__)) || defined(__HAIKU__) || defined(__midipix__)) #include #endif \ /* !_WIN32 && (unix || __unix || __unix__ || (__APPLE__ && __MACH__) || __HAIKU__ || __midipix__) */ #if (defined(_POSIX_VERSION) && _POSIX_VERSION >= 199309L) || defined(__HAIKU__) mbedtls_ms_time_t mbedtls_ms_time(void) { int ret; struct timespec tv; mbedtls_ms_time_t current_ms; #if defined(__linux__) && defined(CLOCK_BOOTTIME) || defined(__midipix__) ret = clock_gettime(CLOCK_BOOTTIME, &tv); #else ret = clock_gettime(CLOCK_MONOTONIC, &tv); #endif if (ret) { return time(NULL) * 1000; } 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 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))/10000; return current_ms; } #else #error "No mbedtls_ms_time available" #endif #endif /* MBEDTLS_HAVE_TIME && !MBEDTLS_PLATFORM_MS_TIME_ALT */