/*

 * 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 <stddef.h>

#ifndef __STDC_WANT_LIB_EXT1__

#define __STDC_WANT_LIB_EXT1__ 1 /* Ask for the C11 gmtime_s() and memset_s() if available */

#endif

#include <string.h>

#if defined(_WIN32)

#include <windows.h>

#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 <sanitizer/msan_interface.h>

#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 <time.h>

#if !defined(_WIN32) && (defined(unix) || \

    defined(__unix) || defined(__unix__) || (defined(__APPLE__) && \

    defined(__MACH__)) || defined(__midipix__))

#include <unistd.h>

#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 <time.h>

#if !defined(_WIN32) && \

    (defined(unix) || defined(__unix) || defined(__unix__) || \

    (defined(__APPLE__) && defined(__MACH__)) || defined(__HAIKU__) || defined(__midipix__))

#include <unistd.h>

#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 <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))/10000;

    return current_ms;

}

#else

#error "No mbedtls_ms_time available"

#endif

#endif /* MBEDTLS_HAVE_TIME && !MBEDTLS_PLATFORM_MS_TIME_ALT */