1 /** 2 * \file platform_util.h 3 * 4 * \brief Common and shared functions used by multiple modules in the Mbed TLS 5 * library. 6 */ 7 /* 8 * Copyright The Mbed TLS Contributors 9 * SPDX-License-Identifier: Apache-2.0 10 * 11 * Licensed under the Apache License, Version 2.0 (the "License"); you may 12 * not use this file except in compliance with the License. 13 * You may obtain a copy of the License at 14 * 15 * http://www.apache.org/licenses/LICENSE-2.0 16 * 17 * Unless required by applicable law or agreed to in writing, software 18 * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT 19 * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 20 * See the License for the specific language governing permissions and 21 * limitations under the License. 22 */ 23 #ifndef MBEDTLS_PLATFORM_UTIL_H 24 #define MBEDTLS_PLATFORM_UTIL_H 25 26 #include "mbedtls/build_info.h" 27 28 #include <stddef.h> 29 #if defined(MBEDTLS_HAVE_TIME_DATE) 30 #include "mbedtls/platform_time.h" 31 #include <time.h> 32 #endif /* MBEDTLS_HAVE_TIME_DATE */ 33 34 #ifdef __cplusplus 35 extern "C" { 36 #endif 37 38 /* Internal macros meant to be called only from within the library. */ 39 #define MBEDTLS_INTERNAL_VALIDATE_RET( cond, ret ) do { } while( 0 ) 40 #define MBEDTLS_INTERNAL_VALIDATE( cond ) do { } while( 0 ) 41 42 /* Internal helper macros for deprecating API constants. */ 43 #if !defined(MBEDTLS_DEPRECATED_REMOVED) 44 #if defined(MBEDTLS_DEPRECATED_WARNING) 45 /* Deliberately don't (yet) export MBEDTLS_DEPRECATED here 46 * to avoid conflict with other headers which define and use 47 * it, too. We might want to move all these definitions here at 48 * some point for uniformity. */ 49 #define MBEDTLS_DEPRECATED __attribute__((deprecated)) 50 MBEDTLS_DEPRECATED typedef char const * mbedtls_deprecated_string_constant_t; 51 #define MBEDTLS_DEPRECATED_STRING_CONSTANT( VAL ) \ 52 ( (mbedtls_deprecated_string_constant_t) ( VAL ) ) 53 MBEDTLS_DEPRECATED typedef int mbedtls_deprecated_numeric_constant_t; 54 #define MBEDTLS_DEPRECATED_NUMERIC_CONSTANT( VAL ) \ 55 ( (mbedtls_deprecated_numeric_constant_t) ( VAL ) ) 56 #undef MBEDTLS_DEPRECATED 57 #else /* MBEDTLS_DEPRECATED_WARNING */ 58 #define MBEDTLS_DEPRECATED_STRING_CONSTANT( VAL ) VAL 59 #define MBEDTLS_DEPRECATED_NUMERIC_CONSTANT( VAL ) VAL 60 #endif /* MBEDTLS_DEPRECATED_WARNING */ 61 #endif /* MBEDTLS_DEPRECATED_REMOVED */ 62 63 /** 64 * \brief Securely zeroize a buffer 65 * 66 * The function is meant to wipe the data contained in a buffer so 67 * that it can no longer be recovered even if the program memory 68 * is later compromised. Call this function on sensitive data 69 * stored on the stack before returning from a function, and on 70 * sensitive data stored on the heap before freeing the heap 71 * object. 72 * 73 * It is extremely difficult to guarantee that calls to 74 * mbedtls_platform_zeroize() are not removed by aggressive 75 * compiler optimizations in a portable way. For this reason, Mbed 76 * TLS provides the configuration option 77 * MBEDTLS_PLATFORM_ZEROIZE_ALT, which allows users to configure 78 * mbedtls_platform_zeroize() to use a suitable implementation for 79 * their platform and needs 80 * 81 * \param buf Buffer to be zeroized 82 * \param len Length of the buffer in bytes 83 * 84 */ 85 void mbedtls_platform_zeroize( void *buf, size_t len ); 86 87 #if defined(MBEDTLS_HAVE_TIME_DATE) 88 /** 89 * \brief Platform-specific implementation of gmtime_r() 90 * 91 * The function is a thread-safe abstraction that behaves 92 * similarly to the gmtime_r() function from Unix/POSIX. 93 * 94 * Mbed TLS will try to identify the underlying platform and 95 * make use of an appropriate underlying implementation (e.g. 96 * gmtime_r() for POSIX and gmtime_s() for Windows). If this is 97 * not possible, then gmtime() will be used. In this case, calls 98 * from the library to gmtime() will be guarded by the mutex 99 * mbedtls_threading_gmtime_mutex if MBEDTLS_THREADING_C is 100 * enabled. It is recommended that calls from outside the library 101 * are also guarded by this mutex. 102 * 103 * If MBEDTLS_PLATFORM_GMTIME_R_ALT is defined, then Mbed TLS will 104 * unconditionally use the alternative implementation for 105 * mbedtls_platform_gmtime_r() supplied by the user at compile time. 106 * 107 * \param tt Pointer to an object containing time (in seconds) since the 108 * epoch to be converted 109 * \param tm_buf Pointer to an object where the results will be stored 110 * 111 * \return Pointer to an object of type struct tm on success, otherwise 112 * NULL 113 */ 114 struct tm *mbedtls_platform_gmtime_r( const mbedtls_time_t *tt, 115 struct tm *tm_buf ); 116 #endif /* MBEDTLS_HAVE_TIME_DATE */ 117 118 #ifdef __cplusplus 119 } 120 #endif 121 122 #endif /* MBEDTLS_PLATFORM_UTIL_H */ 123
