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 #if !defined(MBEDTLS_CONFIG_FILE) 27 #include "mbedtls/config.h" 28 #else 29 #include MBEDTLS_CONFIG_FILE 30 #endif 31 32 #include <stddef.h> 33 #if defined(MBEDTLS_HAVE_TIME_DATE) 34 #include "mbedtls/platform_time.h" 35 #include <time.h> 36 #endif /* MBEDTLS_HAVE_TIME_DATE */ 37 38 #ifdef __cplusplus 39 extern "C" { 40 #endif 41 42 #if defined(MBEDTLS_CHECK_PARAMS) 43 44 #if defined(MBEDTLS_CHECK_PARAMS_ASSERT) 45 /* Allow the user to define MBEDTLS_PARAM_FAILED to something like assert 46 * (which is what our config.h suggests). */ 47 #include <assert.h> 48 #endif /* MBEDTLS_CHECK_PARAMS_ASSERT */ 49 50 #if defined(MBEDTLS_PARAM_FAILED) 51 /** An alternative definition of MBEDTLS_PARAM_FAILED has been set in config.h. 52 * 53 * This flag can be used to check whether it is safe to assume that 54 * MBEDTLS_PARAM_FAILED() will expand to a call to mbedtls_param_failed(). 55 */ 56 #define MBEDTLS_PARAM_FAILED_ALT 57 58 #elif defined(MBEDTLS_CHECK_PARAMS_ASSERT) 59 #define MBEDTLS_PARAM_FAILED( cond ) assert( cond ) 60 #define MBEDTLS_PARAM_FAILED_ALT 61 62 #else /* MBEDTLS_PARAM_FAILED */ 63 #define MBEDTLS_PARAM_FAILED( cond ) \ 64 mbedtls_param_failed( #cond, __FILE__, __LINE__ ) 65 66 /** 67 * \brief User supplied callback function for parameter validation failure. 68 * See #MBEDTLS_CHECK_PARAMS for context. 69 * 70 * This function will be called unless an alternative treatement 71 * is defined through the #MBEDTLS_PARAM_FAILED macro. 72 * 73 * This function can return, and the operation will be aborted, or 74 * alternatively, through use of setjmp()/longjmp() can resume 75 * execution in the application code. 76 * 77 * \param failure_condition The assertion that didn't hold. 78 * \param file The file where the assertion failed. 79 * \param line The line in the file where the assertion failed. 80 */ 81 void mbedtls_param_failed( const char *failure_condition, 82 const char *file, 83 int line ); 84 #endif /* MBEDTLS_PARAM_FAILED */ 85 86 /* Internal macro meant to be called only from within the library. */ 87 #define MBEDTLS_INTERNAL_VALIDATE_RET( cond, ret ) \ 88 do { \ 89 if( !(cond) ) \ 90 { \ 91 MBEDTLS_PARAM_FAILED( cond ); \ 92 return( ret ); \ 93 } \ 94 } while( 0 ) 95 96 /* Internal macro meant to be called only from within the library. */ 97 #define MBEDTLS_INTERNAL_VALIDATE( cond ) \ 98 do { \ 99 if( !(cond) ) \ 100 { \ 101 MBEDTLS_PARAM_FAILED( cond ); \ 102 return; \ 103 } \ 104 } while( 0 ) 105 106 #else /* MBEDTLS_CHECK_PARAMS */ 107 108 /* Internal macros meant to be called only from within the library. */ 109 #define MBEDTLS_INTERNAL_VALIDATE_RET( cond, ret ) do { } while( 0 ) 110 #define MBEDTLS_INTERNAL_VALIDATE( cond ) do { } while( 0 ) 111 112 #endif /* MBEDTLS_CHECK_PARAMS */ 113 114 /* Internal helper macros for deprecating API constants. */ 115 #if !defined(MBEDTLS_DEPRECATED_REMOVED) 116 #if defined(MBEDTLS_DEPRECATED_WARNING) 117 /* Deliberately don't (yet) export MBEDTLS_DEPRECATED here 118 * to avoid conflict with other headers which define and use 119 * it, too. We might want to move all these definitions here at 120 * some point for uniformity. */ 121 #define MBEDTLS_DEPRECATED __attribute__((deprecated)) 122 MBEDTLS_DEPRECATED typedef char const * mbedtls_deprecated_string_constant_t; 123 #define MBEDTLS_DEPRECATED_STRING_CONSTANT( VAL ) \ 124 ( (mbedtls_deprecated_string_constant_t) ( VAL ) ) 125 MBEDTLS_DEPRECATED typedef int mbedtls_deprecated_numeric_constant_t; 126 #define MBEDTLS_DEPRECATED_NUMERIC_CONSTANT( VAL ) \ 127 ( (mbedtls_deprecated_numeric_constant_t) ( VAL ) ) 128 #undef MBEDTLS_DEPRECATED 129 #else /* MBEDTLS_DEPRECATED_WARNING */ 130 #define MBEDTLS_DEPRECATED_STRING_CONSTANT( VAL ) VAL 131 #define MBEDTLS_DEPRECATED_NUMERIC_CONSTANT( VAL ) VAL 132 #endif /* MBEDTLS_DEPRECATED_WARNING */ 133 #endif /* MBEDTLS_DEPRECATED_REMOVED */ 134 135 /** 136 * \brief Securely zeroize a buffer 137 * 138 * The function is meant to wipe the data contained in a buffer so 139 * that it can no longer be recovered even if the program memory 140 * is later compromised. Call this function on sensitive data 141 * stored on the stack before returning from a function, and on 142 * sensitive data stored on the heap before freeing the heap 143 * object. 144 * 145 * It is extremely difficult to guarantee that calls to 146 * mbedtls_platform_zeroize() are not removed by aggressive 147 * compiler optimizations in a portable way. For this reason, Mbed 148 * TLS provides the configuration option 149 * MBEDTLS_PLATFORM_ZEROIZE_ALT, which allows users to configure 150 * mbedtls_platform_zeroize() to use a suitable implementation for 151 * their platform and needs 152 * 153 * \param buf Buffer to be zeroized 154 * \param len Length of the buffer in bytes 155 * 156 */ 157 void mbedtls_platform_zeroize( void *buf, size_t len ); 158 159 #if defined(MBEDTLS_HAVE_TIME_DATE) 160 /** 161 * \brief Platform-specific implementation of gmtime_r() 162 * 163 * The function is a thread-safe abstraction that behaves 164 * similarly to the gmtime_r() function from Unix/POSIX. 165 * 166 * Mbed TLS will try to identify the underlying platform and 167 * make use of an appropriate underlying implementation (e.g. 168 * gmtime_r() for POSIX and gmtime_s() for Windows). If this is 169 * not possible, then gmtime() will be used. In this case, calls 170 * from the library to gmtime() will be guarded by the mutex 171 * mbedtls_threading_gmtime_mutex if MBEDTLS_THREADING_C is 172 * enabled. It is recommended that calls from outside the library 173 * are also guarded by this mutex. 174 * 175 * If MBEDTLS_PLATFORM_GMTIME_R_ALT is defined, then Mbed TLS will 176 * unconditionally use the alternative implementation for 177 * mbedtls_platform_gmtime_r() supplied by the user at compile time. 178 * 179 * \param tt Pointer to an object containing time (in seconds) since the 180 * epoch to be converted 181 * \param tm_buf Pointer to an object where the results will be stored 182 * 183 * \return Pointer to an object of type struct tm on success, otherwise 184 * NULL 185 */ 186 struct tm *mbedtls_platform_gmtime_r( const mbedtls_time_t *tt, 187 struct tm *tm_buf ); 188 #endif /* MBEDTLS_HAVE_TIME_DATE */ 189 190 #ifdef __cplusplus 191 } 192 #endif 193 194 #endif /* MBEDTLS_PLATFORM_UTIL_H */ 195