mirror of
https://github.com/espressif/mbedtls.git
synced 2026-10-10 19:17:23 +00:00
429 lines
13 KiB
C
429 lines
13 KiB
C
/*
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* Common and shared functions used by multiple modules in the Mbed TLS
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* library.
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*
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* Copyright The Mbed TLS Contributors
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* SPDX-License-Identifier: Apache-2.0 OR GPL-2.0-or-later
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*/
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#include "tf_psa_crypto_common.h"
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#include "mbedtls/platform_util.h"
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#include "mbedtls/platform.h"
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#include "mbedtls/threading.h"
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#include "mbedtls/private/error_common.h"
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#include <stddef.h>
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#include <string.h>
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#if defined(_WIN32)
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#include <windows.h>
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#endif
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// Detect platforms known to support explicit_bzero()
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#if defined(__GLIBC__) && (__GLIBC__ >= 2) && (__GLIBC_MINOR__ >= 25)
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/* Note: requires _GNU_SOURCE when compiling with -pedantic */
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#define MBEDTLS_PLATFORM_HAS_EXPLICIT_BZERO 1
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#elif (defined(__FreeBSD__) && (__FreeBSD_version >= 1100037)) || defined(__OpenBSD__)
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#define MBEDTLS_PLATFORM_HAS_EXPLICIT_BZERO 1
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#endif
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#if !defined(MBEDTLS_PLATFORM_ZEROIZE_ALT)
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#undef HAVE_MEMORY_SANITIZER
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#if defined(__has_feature)
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#if __has_feature(memory_sanitizer)
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#include <sanitizer/msan_interface.h>
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#define HAVE_MEMORY_SANITIZER
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#endif
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#endif
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/*
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* Where possible, we try to detect the presence of a platform-provided
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* secure memset, such as explicit_bzero(), that is safe against being optimized
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* out, and use that.
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*
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* For other platforms, we provide an implementation that aims not to be
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* optimized out by the compiler.
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*
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* This implementation for mbedtls_platform_zeroize() was inspired from Colin
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* Percival's blog article at:
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*
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* http://www.daemonology.net/blog/2014-09-04-how-to-zero-a-buffer.html
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*
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* It uses a volatile function pointer to the standard memset(). Because the
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* pointer is volatile the compiler expects it to change at
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* any time and will not optimize out the call that could potentially perform
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* other operations on the input buffer instead of just setting it to 0.
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* Nevertheless, as pointed out by davidtgoldblatt on Hacker News
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* (refer to http://www.daemonology.net/blog/2014-09-05-erratum.html for
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* details), optimizations of the following form are still possible:
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*
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* if (memset_func != memset)
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* memset_func(buf, 0, len);
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*
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* Note that it is extremely difficult to guarantee that
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* the memset() call will not be optimized out by aggressive compilers
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* in a portable way. For this reason, Mbed TLS also provides the configuration
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* option MBEDTLS_PLATFORM_ZEROIZE_ALT, which allows users to configure
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* mbedtls_platform_zeroize() to use a suitable implementation for their
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* platform and needs.
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*/
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#if !defined(MBEDTLS_PLATFORM_HAS_EXPLICIT_BZERO) && !(defined(__STDC_LIB_EXT1__) && \
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!defined(__IAR_SYSTEMS_ICC__)) \
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&& !defined(_WIN32)
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static void *(*const volatile memset_func)(void *, int, size_t) = memset;
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#endif
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void mbedtls_platform_zeroize(void *buf, size_t len)
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{
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if (len > 0) {
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#if defined(MBEDTLS_PLATFORM_HAS_EXPLICIT_BZERO)
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explicit_bzero(buf, len);
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#if defined(HAVE_MEMORY_SANITIZER)
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/* You'd think that Msan would recognize explicit_bzero() as
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* equivalent to bzero(), but it actually doesn't on several
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* platforms, including Linux (Ubuntu 20.04).
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* https://github.com/google/sanitizers/issues/1507
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* https://github.com/openssh/openssh-portable/commit/74433a19bb6f4cef607680fa4d1d7d81ca3826aa
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*/
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__msan_unpoison(buf, len);
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#endif
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#elif defined(__STDC_LIB_EXT1__) && !defined(__IAR_SYSTEMS_ICC__)
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memset_s(buf, len, 0, len);
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#elif defined(_WIN32)
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SecureZeroMemory(buf, len);
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#else
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memset_func(buf, 0, len);
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#endif
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#if defined(__GNUC__)
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/* For clang and recent gcc, pretend that we have some assembly that reads the
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* zero'd memory as an additional protection against being optimised away. */
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#if defined(__clang__) || (__GNUC__ >= 10)
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#if defined(__clang__)
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#pragma clang diagnostic push
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#pragma clang diagnostic ignored "-Wvla"
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#elif defined(MBEDTLS_COMPILER_IS_GCC)
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#pragma GCC diagnostic push
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#pragma GCC diagnostic ignored "-Wvla"
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#endif
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asm volatile ("" : : "m" (*(char (*)[len]) buf) :);
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#if defined(__clang__)
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#pragma clang diagnostic pop
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#elif defined(MBEDTLS_COMPILER_IS_GCC)
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#pragma GCC diagnostic pop
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#endif
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#endif
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#endif
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}
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}
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#endif /* MBEDTLS_PLATFORM_ZEROIZE_ALT */
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void mbedtls_zeroize_and_free(void *buf, size_t len)
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{
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if (buf != NULL) {
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mbedtls_platform_zeroize(buf, len);
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}
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mbedtls_free(buf);
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}
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#if defined(MBEDTLS_HAVE_TIME_DATE) && !defined(MBEDTLS_PLATFORM_GMTIME_R_ALT)
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#include <time.h>
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#if defined(MBEDTLS_PLATFORM_IS_UNIXLIKE)
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#include <unistd.h>
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#endif
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#if !((defined(_POSIX_VERSION) && _POSIX_VERSION >= 200809L) || \
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(defined(_POSIX_THREAD_SAFE_FUNCTIONS) && \
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_POSIX_THREAD_SAFE_FUNCTIONS >= 200112L))
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/*
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* This is a convenience shorthand macro to avoid checking the long
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* preprocessor conditions above. Ideally, we could expose this macro in
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* 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
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* we keep it private by only defining it in this file
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*/
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#if !(defined(_WIN32) && !defined(EFIX64) && !defined(EFI32)) || \
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(defined(__MINGW32__) && !defined(__MINGW64_VERSION_MAJOR))
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#define PLATFORM_UTIL_USE_GMTIME
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#endif
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#endif /* !( ( defined(_POSIX_VERSION) && _POSIX_VERSION >= 200809L ) || \
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( defined(_POSIX_THREAD_SAFE_FUNCTIONS ) && \
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_POSIX_THREAD_SAFE_FUNCTIONS >= 200112L ) ) */
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struct tm *mbedtls_platform_gmtime_r(const mbedtls_time_t *tt,
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struct tm *tm_buf)
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{
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#if defined(_WIN32) && !defined(PLATFORM_UTIL_USE_GMTIME)
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#if defined(__STDC_LIB_EXT1__)
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return (gmtime_s(tt, tm_buf) == 0) ? NULL : tm_buf;
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#else
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/* MSVC and mingw64 argument order and return value are inconsistent with the C11 standard */
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return (gmtime_s(tm_buf, tt) == 0) ? tm_buf : NULL;
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#endif
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#elif !defined(PLATFORM_UTIL_USE_GMTIME)
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return gmtime_r(tt, tm_buf);
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#else
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struct tm *lt;
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#if defined(MBEDTLS_THREADING_C)
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if (mbedtls_mutex_lock(&mbedtls_threading_gmtime_mutex) != 0) {
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return NULL;
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}
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#endif /* MBEDTLS_THREADING_C */
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lt = gmtime(tt);
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if (lt != NULL) {
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memcpy(tm_buf, lt, sizeof(struct tm));
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}
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#if defined(MBEDTLS_THREADING_C)
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if (mbedtls_mutex_unlock(&mbedtls_threading_gmtime_mutex) != 0) {
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return NULL;
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}
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#endif /* MBEDTLS_THREADING_C */
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return (lt == NULL) ? NULL : tm_buf;
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#endif /* _WIN32 && !EFIX64 && !EFI32 */
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}
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#endif /* MBEDTLS_HAVE_TIME_DATE && MBEDTLS_PLATFORM_GMTIME_R_ALT */
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#if defined(MBEDTLS_TEST_HOOKS)
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void (*mbedtls_test_hook_test_fail)(const char *, int, const char *);
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#endif /* MBEDTLS_TEST_HOOKS */
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#if defined(MBEDTLS_HAVE_TIME) && !defined(MBEDTLS_PLATFORM_MS_TIME_ALT)
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#include <time.h>
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#if defined(MBEDTLS_PLATFORM_IS_UNIXLIKE)
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#include <unistd.h>
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#endif
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#if (defined(_POSIX_VERSION) && _POSIX_VERSION >= 199309L) || defined(__HAIKU__)
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mbedtls_ms_time_t mbedtls_ms_time(void)
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{
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int ret;
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struct timespec tv;
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mbedtls_ms_time_t current_ms;
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#if defined(__linux__) && defined(CLOCK_BOOTTIME) || defined(__midipix__)
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ret = clock_gettime(CLOCK_BOOTTIME, &tv);
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#else
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ret = clock_gettime(CLOCK_MONOTONIC, &tv);
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#endif
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if (ret) {
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return time(NULL) * 1000;
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}
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current_ms = tv.tv_sec;
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return current_ms*1000 + tv.tv_nsec / 1000000;
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}
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#elif defined(_WIN32) || defined(WIN32) || defined(__CYGWIN__) || \
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defined(__MINGW32__) || defined(_WIN64)
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#include <windows.h>
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mbedtls_ms_time_t mbedtls_ms_time(void)
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{
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FILETIME ct;
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mbedtls_ms_time_t current_ms;
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GetSystemTimeAsFileTime(&ct);
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current_ms = ((mbedtls_ms_time_t) ct.dwLowDateTime +
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((mbedtls_ms_time_t) (ct.dwHighDateTime) << 32LL))/10000;
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return current_ms;
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}
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#else
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#error "No mbedtls_ms_time available"
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#endif
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#endif /* MBEDTLS_HAVE_TIME && !MBEDTLS_PLATFORM_MS_TIME_ALT */
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#if defined(MBEDTLS_PSA_BUILTIN_GET_ENTROPY)
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#if !defined(MBEDTLS_PLATFORM_IS_UNIXLIKE) && \
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!defined(__MVS__) /* z/OS */ && \
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!defined(_WIN32)
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#error \
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"The built-in entropy sources only work on Unix and Windows. " \
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"Please enable MBEDTLS_PSA_DRIVER_GET_ENTROPY instead of " \
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"MBEDTLS_PSA_BUILTIN_GET_ENTROPY and implement " \
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"mbedtls_platform_get_entropy()."
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#endif
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#include "mbedtls/private/entropy.h"
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#if defined(_WIN32) && !defined(EFIX64) && !defined(EFI32)
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#include <windows.h>
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#include <bcrypt.h>
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#include <intsafe.h>
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int mbedtls_platform_get_entropy(psa_driver_get_entropy_flags_t flags,
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size_t *estimate_bits,
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unsigned char *output, size_t output_size)
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{
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/* We don't implement any flags yet. */
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if (flags != 0) {
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return PSA_ERROR_NOT_SUPPORTED;
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}
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/*
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* BCryptGenRandom takes ULONG for size, which is smaller than size_t on
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* 64-bit Windows platforms.
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*/
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if (output_size > ULONG_MAX) {
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return MBEDTLS_ERR_ENTROPY_SOURCE_FAILED;
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}
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if (!BCRYPT_SUCCESS(BCryptGenRandom(NULL, output, (unsigned long) output_size,
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BCRYPT_USE_SYSTEM_PREFERRED_RNG))) {
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return MBEDTLS_ERR_ENTROPY_SOURCE_FAILED;
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}
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*estimate_bits = 8 * output_size;
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return 0;
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}
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#else /* _WIN32 && !EFIX64 && !EFI32 */
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/*
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* Test for Linux getrandom() support.
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* Since there is no wrapper in the libc yet, use the generic syscall wrapper
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* available in GNU libc and compatible libc's (eg uClibc).
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*/
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#if ((defined(__linux__) && defined(__GLIBC__)) || defined(__midipix__))
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#include <unistd.h>
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#include <sys/syscall.h>
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#if defined(SYS_getrandom)
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#define HAVE_GETRANDOM
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#include <errno.h>
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static int getrandom_wrapper(void *buf, size_t buflen, unsigned int flags)
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{
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/* MemSan cannot understand that the syscall writes to the buffer */
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#if defined(__has_feature)
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#if __has_feature(memory_sanitizer)
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memset(buf, 0, buflen);
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#endif
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#endif
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return (int) syscall(SYS_getrandom, buf, buflen, flags);
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}
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#endif /* SYS_getrandom */
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#endif /* __linux__ || __midipix__ */
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#if defined(__FreeBSD__) || defined(__DragonFly__)
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#include <sys/param.h>
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#if (defined(__FreeBSD__) && __FreeBSD_version >= 1200000) || \
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(defined(__DragonFly__) && __DragonFly_version >= 500700)
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#include <errno.h>
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#include <sys/random.h>
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#define HAVE_GETRANDOM
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static int getrandom_wrapper(void *buf, size_t buflen, unsigned int flags)
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{
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return (int) getrandom(buf, buflen, flags);
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}
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#endif /* (__FreeBSD__ && __FreeBSD_version >= 1200000) ||
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(__DragonFly__ && __DragonFly_version >= 500700) */
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#endif /* __FreeBSD__ || __DragonFly__ */
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/*
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* Some BSD systems provide KERN_ARND.
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* This is equivalent to reading from /dev/urandom, only it doesn't require an
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* open file descriptor, and provides up to 256 bytes per call (basically the
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* same as getentropy(), but with a longer history).
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*
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* Documentation: https://netbsd.gw.com/cgi-bin/man-cgi?sysctl+7
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*/
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#if (defined(__FreeBSD__) || defined(__NetBSD__)) && !defined(HAVE_GETRANDOM)
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#include <sys/param.h>
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#include <sys/sysctl.h>
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#if defined(KERN_ARND)
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#define HAVE_SYSCTL_ARND
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static int sysctl_arnd_wrapper(unsigned char *buf, size_t buflen)
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{
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int name[2];
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size_t len;
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name[0] = CTL_KERN;
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name[1] = KERN_ARND;
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while (buflen > 0) {
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len = buflen > 256 ? 256 : buflen;
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if (sysctl(name, 2, buf, &len, NULL, 0) == -1) {
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return -1;
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}
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buflen -= len;
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buf += len;
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}
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return 0;
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}
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#endif /* KERN_ARND */
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#endif /* __FreeBSD__ || __NetBSD__ */
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#include <stdio.h>
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const char *mbedtls_platform_dev_random = MBEDTLS_PLATFORM_DEV_RANDOM;
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int mbedtls_platform_get_entropy(psa_driver_get_entropy_flags_t flags,
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size_t *estimate_bits,
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unsigned char *output, size_t output_size)
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{
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FILE *file;
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size_t read_len;
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int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
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/* We don't implement any flags yet. */
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if (flags != 0) {
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return PSA_ERROR_NOT_SUPPORTED;
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}
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#if defined(HAVE_GETRANDOM)
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ret = getrandom_wrapper(output, output_size, 0);
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if (ret >= 0) {
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*estimate_bits = 8 * (size_t) ret;
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return 0;
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} else if (errno != ENOSYS) {
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return MBEDTLS_ERR_ENTROPY_SOURCE_FAILED;
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}
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/* Fall through if the system call isn't known. */
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#else
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((void) ret);
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#endif /* HAVE_GETRANDOM */
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#if defined(HAVE_SYSCTL_ARND)
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((void) file);
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((void) read_len);
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if (sysctl_arnd_wrapper(output, output_size) == -1) {
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return MBEDTLS_ERR_ENTROPY_SOURCE_FAILED;
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}
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*estimate_bits = 8 * output_size;
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return 0;
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#else
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file = fopen(mbedtls_platform_dev_random, "rb");
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if (file == NULL) {
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return MBEDTLS_ERR_ENTROPY_SOURCE_FAILED;
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}
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/* Ensure no stdio buffering of secrets, as such buffers cannot be wiped. */
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mbedtls_setbuf(file, NULL);
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read_len = fread(output, 1, output_size, file);
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if (read_len != output_size) {
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fclose(file);
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return MBEDTLS_ERR_ENTROPY_SOURCE_FAILED;
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}
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fclose(file);
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*estimate_bits = 8 * output_size;
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return 0;
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#endif /* HAVE_SYSCTL_ARND */
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}
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#endif /* _WIN32 && !EFIX64 && !EFI32 */
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#endif /* MBEDTLS_PSA_BUILTIN_GET_ENTROPY */
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