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 (C) 2018, Arm Limited, All Rights Reserved 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 * This file is part of Mbed TLS (https://tls.mbed.org) 24 */ 25 #ifndef MBEDTLS_PLATFORM_UTIL_H 26 #define MBEDTLS_PLATFORM_UTIL_H 27 28 #if !defined(MBEDTLS_CONFIG_FILE) 29 #include "mbedtls/config.h" 30 #else 31 #include MBEDTLS_CONFIG_FILE 32 #endif 33 34 #include <stddef.h> 35 #if defined(MBEDTLS_HAVE_TIME_DATE) 36 #include "mbedtls/platform_time.h" 37 #include <time.h> 38 #endif /* MBEDTLS_HAVE_TIME_DATE */ 39 40 #ifdef __cplusplus 41 extern "C" { 42 #endif 43 44 #if defined(MBEDTLS_CHECK_PARAMS) 45 46 #if defined(MBEDTLS_PARAM_FAILED) 47 /** An alternative definition of MBEDTLS_PARAM_FAILED has been set in config.h. 48 * 49 * This flag can be used to check whether it is safe to assume that 50 * MBEDTLS_PARAM_FAILED() will expand to a call to mbedtls_param_failed(). 51 */ 52 #define MBEDTLS_PARAM_FAILED_ALT 53 #else /* MBEDTLS_PARAM_FAILED */ 54 #define MBEDTLS_PARAM_FAILED( cond ) \ 55 mbedtls_param_failed( #cond, __FILE__, __LINE__ ) 56 57 /** 58 * \brief User supplied callback function for parameter validation failure. 59 * See #MBEDTLS_CHECK_PARAMS for context. 60 * 61 * This function will be called unless an alternative treatement 62 * is defined through the #MBEDTLS_PARAM_FAILED macro. 63 * 64 * This function can return, and the operation will be aborted, or 65 * alternatively, through use of setjmp()/longjmp() can resume 66 * execution in the application code. 67 * 68 * \param failure_condition The assertion that didn't hold. 69 * \param file The file where the assertion failed. 70 * \param line The line in the file where the assertion failed. 71 */ 72 void mbedtls_param_failed( const char *failure_condition, 73 const char *file, 74 int line ); 75 #endif /* MBEDTLS_PARAM_FAILED */ 76 77 /* Internal macro meant to be called only from within the library. */ 78 #define MBEDTLS_INTERNAL_VALIDATE_RET( cond, ret ) \ 79 do { \ 80 if( !(cond) ) \ 81 { \ 82 MBEDTLS_PARAM_FAILED( cond ); \ 83 return( ret ); \ 84 } \ 85 } while( 0 ) 86 87 /* Internal macro meant to be called only from within the library. */ 88 #define MBEDTLS_INTERNAL_VALIDATE( cond ) \ 89 do { \ 90 if( !(cond) ) \ 91 { \ 92 MBEDTLS_PARAM_FAILED( cond ); \ 93 return; \ 94 } \ 95 } while( 0 ) 96 97 #else /* MBEDTLS_CHECK_PARAMS */ 98 99 /* Internal macros meant to be called only from within the library. */ 100 #define MBEDTLS_INTERNAL_VALIDATE_RET( cond, ret ) do { } while( 0 ) 101 #define MBEDTLS_INTERNAL_VALIDATE( cond ) do { } while( 0 ) 102 103 #endif /* MBEDTLS_CHECK_PARAMS */ 104 105 /* Internal helper macros for deprecating API constants. */ 106 #if !defined(MBEDTLS_DEPRECATED_REMOVED) 107 #if defined(MBEDTLS_DEPRECATED_WARNING) 108 /* Deliberately don't (yet) export MBEDTLS_DEPRECATED here 109 * to avoid conflict with other headers which define and use 110 * it, too. We might want to move all these definitions here at 111 * some point for uniformity. */ 112 #define MBEDTLS_DEPRECATED __attribute__((deprecated)) 113 MBEDTLS_DEPRECATED typedef char const * mbedtls_deprecated_string_constant_t; 114 #define MBEDTLS_DEPRECATED_STRING_CONSTANT( VAL ) \ 115 ( (mbedtls_deprecated_string_constant_t) ( VAL ) ) 116 MBEDTLS_DEPRECATED typedef int mbedtls_deprecated_numeric_constant_t; 117 #define MBEDTLS_DEPRECATED_NUMERIC_CONSTANT( VAL ) \ 118 ( (mbedtls_deprecated_numeric_constant_t) ( VAL ) ) 119 #undef MBEDTLS_DEPRECATED 120 #else /* MBEDTLS_DEPRECATED_WARNING */ 121 #define MBEDTLS_DEPRECATED_STRING_CONSTANT( VAL ) VAL 122 #define MBEDTLS_DEPRECATED_NUMERIC_CONSTANT( VAL ) VAL 123 #endif /* MBEDTLS_DEPRECATED_WARNING */ 124 #endif /* MBEDTLS_DEPRECATED_REMOVED */ 125 126 /** 127 * \brief Securely zeroize a buffer 128 * 129 * The function is meant to wipe the data contained in a buffer so 130 * that it can no longer be recovered even if the program memory 131 * is later compromised. Call this function on sensitive data 132 * stored on the stack before returning from a function, and on 133 * sensitive data stored on the heap before freeing the heap 134 * object. 135 * 136 * It is extremely difficult to guarantee that calls to 137 * mbedtls_platform_zeroize() are not removed by aggressive 138 * compiler optimizations in a portable way. For this reason, Mbed 139 * TLS provides the configuration option 140 * MBEDTLS_PLATFORM_ZEROIZE_ALT, which allows users to configure 141 * mbedtls_platform_zeroize() to use a suitable implementation for 142 * their platform and needs 143 * 144 * \param buf Buffer to be zeroized 145 * \param len Length of the buffer in bytes 146 * 147 */ 148 void mbedtls_platform_zeroize( void *buf, size_t len ); 149 150 #if defined(MBEDTLS_HAVE_TIME_DATE) 151 /** 152 * \brief Platform-specific implementation of gmtime_r() 153 * 154 * The function is a thread-safe abstraction that behaves 155 * similarly to the gmtime_r() function from Unix/POSIX. 156 * 157 * Mbed TLS will try to identify the underlying platform and 158 * make use of an appropriate underlying implementation (e.g. 159 * gmtime_r() for POSIX and gmtime_s() for Windows). If this is 160 * not possible, then gmtime() will be used. In this case, calls 161 * from the library to gmtime() will be guarded by the mutex 162 * mbedtls_threading_gmtime_mutex if MBEDTLS_THREADING_C is 163 * enabled. It is recommended that calls from outside the library 164 * are also guarded by this mutex. 165 * 166 * If MBEDTLS_PLATFORM_GMTIME_R_ALT is defined, then Mbed TLS will 167 * unconditionally use the alternative implementation for 168 * mbedtls_platform_gmtime_r() supplied by the user at compile time. 169 * 170 * \param tt Pointer to an object containing time (in seconds) since the 171 * epoch to be converted 172 * \param tm_buf Pointer to an object where the results will be stored 173 * 174 * \return Pointer to an object of type struct tm on success, otherwise 175 * NULL 176 */ 177 struct tm *mbedtls_platform_gmtime_r( const mbedtls_time_t *tt, 178 struct tm *tm_buf ); 179 #endif /* MBEDTLS_HAVE_TIME_DATE */ 180 181 #ifdef __cplusplus 182 } 183 #endif 184 185 #endif /* MBEDTLS_PLATFORM_UTIL_H */ 186