NCBI C++ ToolKit
platform_util.h
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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 treatment
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 /* Implementation of the check-return facility.
136  * See the user documentation in config.h.
137  *
138  * Do not use this macro directly to annotate function: instead,
139  * use one of MBEDTLS_CHECK_RETURN_CRITICAL or MBEDTLS_CHECK_RETURN_TYPICAL
140  * depending on how important it is to check the return value.
141  */
142 #if !defined(MBEDTLS_CHECK_RETURN)
143 #if defined(__GNUC__)
144 #define MBEDTLS_CHECK_RETURN __attribute__((__warn_unused_result__))
145 #elif defined(_MSC_VER) && _MSC_VER >= 1700
146 #include <sal.h>
147 #define MBEDTLS_CHECK_RETURN _Check_return_
148 #else
149 #define MBEDTLS_CHECK_RETURN
150 #endif
151 #endif
152 
153 /** Critical-failure function
154  *
155  * This macro appearing at the beginning of the declaration of a function
156  * indicates that its return value should be checked in all applications.
157  * Omitting the check is very likely to indicate a bug in the application
158  * and will result in a compile-time warning if #MBEDTLS_CHECK_RETURN
159  * is implemented for the compiler in use.
160  *
161  * \note The use of this macro is a work in progress.
162  * This macro may be added to more functions in the future.
163  * Such an extension is not considered an API break, provided that
164  * there are near-unavoidable circumstances under which the function
165  * can fail. For example, signature/MAC/AEAD verification functions,
166  * and functions that require a random generator, are considered
167  * return-check-critical.
168  */
169 #define MBEDTLS_CHECK_RETURN_CRITICAL MBEDTLS_CHECK_RETURN
170 
171 /** Ordinary-failure function
172  *
173  * This macro appearing at the beginning of the declaration of a function
174  * indicates that its return value should be generally be checked in portable
175  * applications. Omitting the check will result in a compile-time warning if
176  * #MBEDTLS_CHECK_RETURN is implemented for the compiler in use and
177  * #MBEDTLS_CHECK_RETURN_WARNING is enabled in the compile-time configuration.
178  *
179  * You can use #MBEDTLS_IGNORE_RETURN to explicitly ignore the return value
180  * of a function that is annotated with #MBEDTLS_CHECK_RETURN.
181  *
182  * \note The use of this macro is a work in progress.
183  * This macro will be added to more functions in the future.
184  * Eventually this should appear before most functions returning
185  * an error code (as \c int in the \c mbedtls_xxx API or
186  * as ::psa_status_t in the \c psa_xxx API).
187  */
188 #if defined(MBEDTLS_CHECK_RETURN_WARNING)
189 #define MBEDTLS_CHECK_RETURN_TYPICAL MBEDTLS_CHECK_RETURN
190 #else
191 #define MBEDTLS_CHECK_RETURN_TYPICAL
192 #endif
193 
194 /** Benign-failure function
195  *
196  * This macro appearing at the beginning of the declaration of a function
197  * indicates that it is rarely useful to check its return value.
198  *
199  * This macro has an empty expansion. It exists for documentation purposes:
200  * a #MBEDTLS_CHECK_RETURN_OPTIONAL annotation indicates that the function
201  * has been analyzed for return-check usefulness, whereas the lack of
202  * an annotation indicates that the function has not been analyzed and its
203  * return-check usefulness is unknown.
204  */
205 #define MBEDTLS_CHECK_RETURN_OPTIONAL
206 
207 /** \def MBEDTLS_IGNORE_RETURN
208  *
209  * Call this macro with one argument, a function call, to suppress a warning
210  * from #MBEDTLS_CHECK_RETURN due to that function call.
211  */
212 #if !defined(MBEDTLS_IGNORE_RETURN)
213 /* GCC doesn't silence the warning with just (void)(result).
214  * (void)!(result) is known to work up at least up to GCC 10, as well
215  * as with Clang and MSVC.
216  *
217  * https://gcc.gnu.org/onlinedocs/gcc-3.4.6/gcc/Non_002dbugs.html
218  * https://stackoverflow.com/questions/40576003/ignoring-warning-wunused-result
219  * https://gcc.gnu.org/bugzilla/show_bug.cgi?id=66425#c34
220  */
221 #define MBEDTLS_IGNORE_RETURN(result) ((void) !(result))
222 #endif
223 
224 /**
225  * \brief Securely zeroize a buffer
226  *
227  * The function is meant to wipe the data contained in a buffer so
228  * that it can no longer be recovered even if the program memory
229  * is later compromised. Call this function on sensitive data
230  * stored on the stack before returning from a function, and on
231  * sensitive data stored on the heap before freeing the heap
232  * object.
233  *
234  * It is extremely difficult to guarantee that calls to
235  * mbedtls_platform_zeroize() are not removed by aggressive
236  * compiler optimizations in a portable way. For this reason, Mbed
237  * TLS provides the configuration option
238  * MBEDTLS_PLATFORM_ZEROIZE_ALT, which allows users to configure
239  * mbedtls_platform_zeroize() to use a suitable implementation for
240  * their platform and needs
241  *
242  * \param buf Buffer to be zeroized
243  * \param len Length of the buffer in bytes
244  *
245  */
246 void mbedtls_platform_zeroize(void *buf, size_t len);
247 
248 #if defined(MBEDTLS_HAVE_TIME_DATE)
249 /**
250  * \brief Platform-specific implementation of gmtime_r()
251  *
252  * The function is a thread-safe abstraction that behaves
253  * similarly to the gmtime_r() function from Unix/POSIX.
254  *
255  * Mbed TLS will try to identify the underlying platform and
256  * make use of an appropriate underlying implementation (e.g.
257  * gmtime_r() for POSIX and gmtime_s() for Windows). If this is
258  * not possible, then gmtime() will be used. In this case, calls
259  * from the library to gmtime() will be guarded by the mutex
260  * mbedtls_threading_gmtime_mutex if MBEDTLS_THREADING_C is
261  * enabled. It is recommended that calls from outside the library
262  * are also guarded by this mutex.
263  *
264  * If MBEDTLS_PLATFORM_GMTIME_R_ALT is defined, then Mbed TLS will
265  * unconditionally use the alternative implementation for
266  * mbedtls_platform_gmtime_r() supplied by the user at compile time.
267  *
268  * \param tt Pointer to an object containing time (in seconds) since the
269  * epoch to be converted
270  * \param tm_buf Pointer to an object where the results will be stored
271  *
272  * \return Pointer to an object of type struct tm on success, otherwise
273  * NULL
274  */
275 struct tm *mbedtls_platform_gmtime_r(const mbedtls_time_t *tt,
276  struct tm *tm_buf);
277 #endif /* MBEDTLS_HAVE_TIME_DATE */
278 
279 #ifdef __cplusplus
280 }
281 #endif
282 
283 #endif /* MBEDTLS_PLATFORM_UTIL_H */
#define MBEDTLS_DEPRECATED
Definition: aes.h:637
FILE * file
char * buf
int len
#define mbedtls_platform_gmtime_r
mbed TLS Platform time abstraction
time_t mbedtls_time_t
Definition: platform_time.h:43
void mbedtls_platform_zeroize(void *buf, size_t len)
Securely zeroize a buffer.
Configuration options (set of defines)
Modified on Mon Mar 04 05:09:42 2024 by modify_doxy.py rev. 669887