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Diffstat (limited to 'include/mbedtls/platform_util.h')
| -rw-r--r-- | include/mbedtls/platform_util.h | 201 |
1 files changed, 201 insertions, 0 deletions
diff --git a/include/mbedtls/platform_util.h b/include/mbedtls/platform_util.h new file mode 100644 index 0000000..cba02ab --- /dev/null +++ b/include/mbedtls/platform_util.h @@ -0,0 +1,201 @@ +/** + * \file platform_util.h + * + * \brief 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 + */ +#ifndef MBEDTLS_PLATFORM_UTIL_H +#define MBEDTLS_PLATFORM_UTIL_H + +#include "mbedtls/build_info.h" + +#include <stddef.h> +#if defined(MBEDTLS_HAVE_TIME_DATE) +#include "mbedtls/platform_time.h" +#include <time.h> +#endif /* MBEDTLS_HAVE_TIME_DATE */ + +#ifdef __cplusplus +extern "C" { +#endif + +/* Internal macros meant to be called only from within the library. */ +#define MBEDTLS_INTERNAL_VALIDATE_RET(cond, ret) do { } while (0) +#define MBEDTLS_INTERNAL_VALIDATE(cond) do { } while (0) + +/* Internal helper macros for deprecating API constants. */ +#if !defined(MBEDTLS_DEPRECATED_REMOVED) +#if defined(MBEDTLS_DEPRECATED_WARNING) +#define MBEDTLS_DEPRECATED __attribute__((deprecated)) +MBEDTLS_DEPRECATED typedef char const *mbedtls_deprecated_string_constant_t; +#define MBEDTLS_DEPRECATED_STRING_CONSTANT(VAL) \ + ((mbedtls_deprecated_string_constant_t) (VAL)) +MBEDTLS_DEPRECATED typedef int mbedtls_deprecated_numeric_constant_t; +#define MBEDTLS_DEPRECATED_NUMERIC_CONSTANT(VAL) \ + ((mbedtls_deprecated_numeric_constant_t) (VAL)) +#else /* MBEDTLS_DEPRECATED_WARNING */ +#define MBEDTLS_DEPRECATED +#define MBEDTLS_DEPRECATED_STRING_CONSTANT(VAL) VAL +#define MBEDTLS_DEPRECATED_NUMERIC_CONSTANT(VAL) VAL +#endif /* MBEDTLS_DEPRECATED_WARNING */ +#endif /* MBEDTLS_DEPRECATED_REMOVED */ + +/* Implementation of the check-return facility. + * See the user documentation in mbedtls_config.h. + * + * Do not use this macro directly to annotate function: instead, + * use one of MBEDTLS_CHECK_RETURN_CRITICAL or MBEDTLS_CHECK_RETURN_TYPICAL + * depending on how important it is to check the return value. + */ +#if !defined(MBEDTLS_CHECK_RETURN) +#if defined(__GNUC__) +#define MBEDTLS_CHECK_RETURN __attribute__((__warn_unused_result__)) +#elif defined(_MSC_VER) && _MSC_VER >= 1700 +#include <sal.h> +#define MBEDTLS_CHECK_RETURN _Check_return_ +#else +#define MBEDTLS_CHECK_RETURN +#endif +#endif + +/** Critical-failure function + * + * This macro appearing at the beginning of the declaration of a function + * indicates that its return value should be checked in all applications. + * Omitting the check is very likely to indicate a bug in the application + * and will result in a compile-time warning if #MBEDTLS_CHECK_RETURN + * is implemented for the compiler in use. + * + * \note The use of this macro is a work in progress. + * This macro may be added to more functions in the future. + * Such an extension is not considered an API break, provided that + * there are near-unavoidable circumstances under which the function + * can fail. For example, signature/MAC/AEAD verification functions, + * and functions that require a random generator, are considered + * return-check-critical. + */ +#define MBEDTLS_CHECK_RETURN_CRITICAL MBEDTLS_CHECK_RETURN + +/** Ordinary-failure function + * + * This macro appearing at the beginning of the declaration of a function + * indicates that its return value should be generally be checked in portable + * applications. Omitting the check will result in a compile-time warning if + * #MBEDTLS_CHECK_RETURN is implemented for the compiler in use and + * #MBEDTLS_CHECK_RETURN_WARNING is enabled in the compile-time configuration. + * + * You can use #MBEDTLS_IGNORE_RETURN to explicitly ignore the return value + * of a function that is annotated with #MBEDTLS_CHECK_RETURN. + * + * \note The use of this macro is a work in progress. + * This macro will be added to more functions in the future. + * Eventually this should appear before most functions returning + * an error code (as \c int in the \c mbedtls_xxx API or + * as ::psa_status_t in the \c psa_xxx API). + */ +#if defined(MBEDTLS_CHECK_RETURN_WARNING) +#define MBEDTLS_CHECK_RETURN_TYPICAL MBEDTLS_CHECK_RETURN +#else +#define MBEDTLS_CHECK_RETURN_TYPICAL +#endif + +/** Benign-failure function + * + * This macro appearing at the beginning of the declaration of a function + * indicates that it is rarely useful to check its return value. + * + * This macro has an empty expansion. It exists for documentation purposes: + * a #MBEDTLS_CHECK_RETURN_OPTIONAL annotation indicates that the function + * has been analyzed for return-check usefulness, whereas the lack of + * an annotation indicates that the function has not been analyzed and its + * return-check usefulness is unknown. + */ +#define MBEDTLS_CHECK_RETURN_OPTIONAL + +/** \def MBEDTLS_IGNORE_RETURN + * + * Call this macro with one argument, a function call, to suppress a warning + * from #MBEDTLS_CHECK_RETURN due to that function call. + */ +#if !defined(MBEDTLS_IGNORE_RETURN) +/* GCC doesn't silence the warning with just (void)(result). + * (void)!(result) is known to work up at least up to GCC 10, as well + * as with Clang and MSVC. + * + * https://gcc.gnu.org/onlinedocs/gcc-3.4.6/gcc/Non_002dbugs.html + * https://stackoverflow.com/questions/40576003/ignoring-warning-wunused-result + * https://gcc.gnu.org/bugzilla/show_bug.cgi?id=66425#c34 + */ +#define MBEDTLS_IGNORE_RETURN(result) ((void) !(result)) +#endif + +/* If the following macro is defined, the library is being built by the test + * framework, and the framework is going to provide a replacement + * mbedtls_platform_zeroize() using a preprocessor macro, so the function + * declaration should be omitted. */ +#if !defined(MBEDTLS_TEST_DEFINES_ZEROIZE) //no-check-names +/** + * \brief Securely zeroize a buffer + * + * The function is meant to wipe the data contained in a buffer so + * that it can no longer be recovered even if the program memory + * is later compromised. Call this function on sensitive data + * stored on the stack before returning from a function, and on + * sensitive data stored on the heap before freeing the heap + * object. + * + * It is extremely difficult to guarantee that calls to + * mbedtls_platform_zeroize() are not removed by aggressive + * compiler optimizations in a portable way. For this reason, Mbed + * TLS 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 + * + * \param buf Buffer to be zeroized + * \param len Length of the buffer in bytes + * + */ +void mbedtls_platform_zeroize(void *buf, size_t len); +#endif + +#if defined(MBEDTLS_HAVE_TIME_DATE) +/** + * \brief Platform-specific implementation of gmtime_r() + * + * The function is a thread-safe abstraction that behaves + * similarly to the gmtime_r() function from Unix/POSIX. + * + * Mbed TLS will try to identify the underlying platform and + * make use of an appropriate underlying implementation (e.g. + * gmtime_r() for POSIX and gmtime_s() for Windows). If this is + * not possible, then gmtime() will be used. In this case, calls + * from the library to gmtime() will be guarded by the mutex + * mbedtls_threading_gmtime_mutex if MBEDTLS_THREADING_C is + * enabled. It is recommended that calls from outside the library + * are also guarded by this mutex. + * + * If MBEDTLS_PLATFORM_GMTIME_R_ALT is defined, then Mbed TLS will + * unconditionally use the alternative implementation for + * mbedtls_platform_gmtime_r() supplied by the user at compile time. + * + * \param tt Pointer to an object containing time (in seconds) since the + * epoch to be converted + * \param tm_buf Pointer to an object where the results will be stored + * + * \return Pointer to an object of type struct tm on success, otherwise + * NULL + */ +struct tm *mbedtls_platform_gmtime_r(const mbedtls_time_t *tt, + struct tm *tm_buf); +#endif /* MBEDTLS_HAVE_TIME_DATE */ + +#ifdef __cplusplus +} +#endif + +#endif /* MBEDTLS_PLATFORM_UTIL_H */ |