1 /* Copyright (C) 1995-1998 Eric Young (eay@cryptsoft.com)
2  * All rights reserved.
3  *
4  * This package is an SSL implementation written
5  * by Eric Young (eay@cryptsoft.com).
6  * The implementation was written so as to conform with Netscapes SSL.
7  *
8  * This library is free for commercial and non-commercial use as long as
9  * the following conditions are aheared to.  The following conditions
10  * apply to all code found in this distribution, be it the RC4, RSA,
11  * lhash, DES, etc., code; not just the SSL code.  The SSL documentation
12  * included with this distribution is covered by the same copyright terms
13  * except that the holder is Tim Hudson (tjh@cryptsoft.com).
14  *
15  * Copyright remains Eric Young's, and as such any Copyright notices in
16  * the code are not to be removed.
17  * If this package is used in a product, Eric Young should be given attribution
18  * as the author of the parts of the library used.
19  * This can be in the form of a textual message at program startup or
20  * in documentation (online or textual) provided with the package.
21  *
22  * Redistribution and use in source and binary forms, with or without
23  * modification, are permitted provided that the following conditions
24  * are met:
25  * 1. Redistributions of source code must retain the copyright
26  *    notice, this list of conditions and the following disclaimer.
27  * 2. Redistributions in binary form must reproduce the above copyright
28  *    notice, this list of conditions and the following disclaimer in the
29  *    documentation and/or other materials provided with the distribution.
30  * 3. All advertising materials mentioning features or use of this software
31  *    must display the following acknowledgement:
32  *    "This product includes cryptographic software written by
33  *     Eric Young (eay@cryptsoft.com)"
34  *    The word 'cryptographic' can be left out if the rouines from the library
35  *    being used are not cryptographic related :-).
36  * 4. If you include any Windows specific code (or a derivative thereof) from
37  *    the apps directory (application code) you must include an acknowledgement:
38  *    "This product includes software written by Tim Hudson (tjh@cryptsoft.com)"
39  *
40  * THIS SOFTWARE IS PROVIDED BY ERIC YOUNG ``AS IS'' AND
41  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
42  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
43  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
44  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
45  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
46  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
47  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
48  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
49  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
50  * SUCH DAMAGE.
51  *
52  * The licence and distribution terms for any publically available version or
53  * derivative of this code cannot be changed.  i.e. this code cannot simply be
54  * copied and put under another distribution licence
55  * [including the GNU Public Licence.]
56  */
57 /* ====================================================================
58  * Copyright (c) 1998-2001 The OpenSSL Project.  All rights reserved.
59  *
60  * Redistribution and use in source and binary forms, with or without
61  * modification, are permitted provided that the following conditions
62  * are met:
63  *
64  * 1. Redistributions of source code must retain the above copyright
65  *    notice, this list of conditions and the following disclaimer.
66  *
67  * 2. Redistributions in binary form must reproduce the above copyright
68  *    notice, this list of conditions and the following disclaimer in
69  *    the documentation and/or other materials provided with the
70  *    distribution.
71  *
72  * 3. All advertising materials mentioning features or use of this
73  *    software must display the following acknowledgment:
74  *    "This product includes software developed by the OpenSSL Project
75  *    for use in the OpenSSL Toolkit. (http://www.openssl.org/)"
76  *
77  * 4. The names "OpenSSL Toolkit" and "OpenSSL Project" must not be used to
78  *    endorse or promote products derived from this software without
79  *    prior written permission. For written permission, please contact
80  *    openssl-core@openssl.org.
81  *
82  * 5. Products derived from this software may not be called "OpenSSL"
83  *    nor may "OpenSSL" appear in their names without prior written
84  *    permission of the OpenSSL Project.
85  *
86  * 6. Redistributions of any form whatsoever must retain the following
87  *    acknowledgment:
88  *    "This product includes software developed by the OpenSSL Project
89  *    for use in the OpenSSL Toolkit (http://www.openssl.org/)"
90  *
91  * THIS SOFTWARE IS PROVIDED BY THE OpenSSL PROJECT ``AS IS'' AND ANY
92  * EXPRESSED OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
93  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
94  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE OpenSSL PROJECT OR
95  * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
96  * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
97  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
98  * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
99  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
100  * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
101  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
102  * OF THE POSSIBILITY OF SUCH DAMAGE.
103  * ====================================================================
104  *
105  * This product includes cryptographic software written by Eric Young
106  * (eay@cryptsoft.com).  This product includes software written by Tim
107  * Hudson (tjh@cryptsoft.com). */
108 
109 #ifndef OPENSSL_HEADER_CRYPTO_INTERNAL_H
110 #define OPENSSL_HEADER_CRYPTO_INTERNAL_H
111 
112 #include <openssl/ex_data.h>
113 #include <openssl/thread.h>
114 
115 #if defined(OPENSSL_NO_THREADS)
116 #elif defined(OPENSSL_WINDOWS)
117 #pragma warning(push, 3)
118 #include <windows.h>
119 #pragma warning(pop)
120 #else
121 #include <pthread.h>
122 #endif
123 
124 #if defined(__cplusplus)
125 extern "C" {
126 #endif
127 
128 
129 /* MSVC's C4701 warning about the use of *potentially*--as opposed to
130  * *definitely*--uninitialized values sometimes has false positives. Usually
131  * the false positives can and should be worked around by simplifying the
132  * control flow. When that is not practical, annotate the function containing
133  * the code that triggers the warning with
134  * OPENSSL_SUPPRESS_POTENTIALLY_UNINITIALIZED_WARNINGS after its parameters:
135  *
136  *    void f() OPENSSL_SUPPRESS_POTENTIALLY_UNINITIALIZED_WARNINGS {
137  *       ...
138  *    }
139  *
140  * Note that MSVC's control flow analysis seems to operate on a whole-function
141  * basis, so the annotation must be placed on the entire function, not just a
142  * block within the function. */
143 #if defined(_MSC_VER)
144 #define OPENSSL_SUPPRESS_POTENTIALLY_UNINITIALIZED_WARNINGS \
145         __pragma(warning(suppress:4701))
146 #else
147 #define OPENSSL_SUPPRESS_POTENTIALLY_UNINITIALIZED_WARNINGS
148 #endif
149 
150 /* MSVC will sometimes correctly detect unreachable code and issue a warning,
151  * which breaks the build since we treat errors as warnings, in some rare cases
152  * where we want to allow the dead code to continue to exist. In these
153  * situations, annotate the function containing the unreachable code with
154  * OPENSSL_SUPPRESS_UNREACHABLE_CODE_WARNINGS after its parameters:
155  *
156  *    void f() OPENSSL_SUPPRESS_UNREACHABLE_CODE_WARNINGS {
157  *       ...
158  *    }
159  *
160  * Note that MSVC's reachability analysis seems to operate on a whole-function
161  * basis, so the annotation must be placed on the entire function, not just a
162  * block within the function. */
163 #if defined(_MSC_VER)
164 #define OPENSSL_SUPPRESS_UNREACHABLE_CODE_WARNINGS \
165         __pragma(warning(suppress:4702))
166 #else
167 #define OPENSSL_SUPPRESS_UNREACHABLE_CODE_WARNINGS
168 #endif
169 
170 
171 #if defined(OPENSSL_X86) || defined(OPENSSL_X86_64) || defined(OPENSSL_ARM) || \
172     defined(OPENSSL_AARCH64)
173 /* OPENSSL_cpuid_setup initializes OPENSSL_ia32cap_P. */
174 void OPENSSL_cpuid_setup(void);
175 #endif
176 
177 #if !defined(inline)
178 #define inline __inline
179 #endif
180 
181 
182 /* Constant-time utility functions.
183  *
184  * The following methods return a bitmask of all ones (0xff...f) for true and 0
185  * for false. This is useful for choosing a value based on the result of a
186  * conditional in constant time. For example,
187  *
188  * if (a < b) {
189  *   c = a;
190  * } else {
191  *   c = b;
192  * }
193  *
194  * can be written as
195  *
196  * unsigned int lt = constant_time_lt(a, b);
197  * c = constant_time_select(lt, a, b); */
198 
199 /* constant_time_msb returns the given value with the MSB copied to all the
200  * other bits. */
constant_time_msb(unsigned int a)201 static inline unsigned int constant_time_msb(unsigned int a) {
202   return (unsigned int)((int)(a) >> (sizeof(int) * 8 - 1));
203 }
204 
205 /* constant_time_lt returns 0xff..f if a < b and 0 otherwise. */
constant_time_lt(unsigned int a,unsigned int b)206 static inline unsigned int constant_time_lt(unsigned int a, unsigned int b) {
207   /* Consider the two cases of the problem:
208    *   msb(a) == msb(b): a < b iff the MSB of a - b is set.
209    *   msb(a) != msb(b): a < b iff the MSB of b is set.
210    *
211    * If msb(a) == msb(b) then the following evaluates as:
212    *   msb(a^((a^b)|((a-b)^a))) ==
213    *   msb(a^((a-b) ^ a))       ==   (because msb(a^b) == 0)
214    *   msb(a^a^(a-b))           ==   (rearranging)
215    *   msb(a-b)                      (because ∀x. x^x == 0)
216    *
217    * Else, if msb(a) != msb(b) then the following evaluates as:
218    *   msb(a^((a^b)|((a-b)^a))) ==
219    *   msb(a^(�� | ((a-b)^a)))   ==   (because msb(a^b) == 1 and ��
220    *                                  represents a value s.t. msb(��) = 1)
221    *   msb(a^��)                 ==   (because ORing with 1 results in 1)
222    *   msb(b)
223    *
224    *
225    * Here is an SMT-LIB verification of this formula:
226    *
227    * (define-fun lt ((a (_ BitVec 32)) (b (_ BitVec 32))) (_ BitVec 32)
228    *   (bvxor a (bvor (bvxor a b) (bvxor (bvsub a b) a)))
229    * )
230    *
231    * (declare-fun a () (_ BitVec 32))
232    * (declare-fun b () (_ BitVec 32))
233    *
234    * (assert (not (= (= #x00000001 (bvlshr (lt a b) #x0000001f)) (bvult a b))))
235    * (check-sat)
236    * (get-model)
237    */
238   return constant_time_msb(a^((a^b)|((a-b)^a)));
239 }
240 
241 /* constant_time_lt_8 acts like |constant_time_lt| but returns an 8-bit mask. */
constant_time_lt_8(unsigned int a,unsigned int b)242 static inline uint8_t constant_time_lt_8(unsigned int a, unsigned int b) {
243   return (uint8_t)(constant_time_lt(a, b));
244 }
245 
246 /* constant_time_gt returns 0xff..f if a >= b and 0 otherwise. */
constant_time_ge(unsigned int a,unsigned int b)247 static inline unsigned int constant_time_ge(unsigned int a, unsigned int b) {
248   return ~constant_time_lt(a, b);
249 }
250 
251 /* constant_time_ge_8 acts like |constant_time_ge| but returns an 8-bit mask. */
constant_time_ge_8(unsigned int a,unsigned int b)252 static inline uint8_t constant_time_ge_8(unsigned int a, unsigned int b) {
253   return (uint8_t)(constant_time_ge(a, b));
254 }
255 
256 /* constant_time_is_zero returns 0xff..f if a == 0 and 0 otherwise. */
constant_time_is_zero(unsigned int a)257 static inline unsigned int constant_time_is_zero(unsigned int a) {
258   /* Here is an SMT-LIB verification of this formula:
259    *
260    * (define-fun is_zero ((a (_ BitVec 32))) (_ BitVec 32)
261    *   (bvand (bvnot a) (bvsub a #x00000001))
262    * )
263    *
264    * (declare-fun a () (_ BitVec 32))
265    *
266    * (assert (not (= (= #x00000001 (bvlshr (is_zero a) #x0000001f)) (= a #x00000000))))
267    * (check-sat)
268    * (get-model)
269    */
270   return constant_time_msb(~a & (a - 1));
271 }
272 
273 /* constant_time_is_zero_8 acts like constant_time_is_zero but returns an 8-bit
274  * mask. */
constant_time_is_zero_8(unsigned int a)275 static inline uint8_t constant_time_is_zero_8(unsigned int a) {
276   return (uint8_t)(constant_time_is_zero(a));
277 }
278 
279 /* constant_time_eq returns 0xff..f if a == b and 0 otherwise. */
constant_time_eq(unsigned int a,unsigned int b)280 static inline unsigned int constant_time_eq(unsigned int a, unsigned int b) {
281   return constant_time_is_zero(a ^ b);
282 }
283 
284 /* constant_time_eq_8 acts like |constant_time_eq| but returns an 8-bit mask. */
constant_time_eq_8(unsigned int a,unsigned int b)285 static inline uint8_t constant_time_eq_8(unsigned int a, unsigned int b) {
286   return (uint8_t)(constant_time_eq(a, b));
287 }
288 
289 /* constant_time_eq_int acts like |constant_time_eq| but works on int values. */
constant_time_eq_int(int a,int b)290 static inline unsigned int constant_time_eq_int(int a, int b) {
291   return constant_time_eq((unsigned)(a), (unsigned)(b));
292 }
293 
294 /* constant_time_eq_int_8 acts like |constant_time_eq_int| but returns an 8-bit
295  * mask. */
constant_time_eq_int_8(int a,int b)296 static inline uint8_t constant_time_eq_int_8(int a, int b) {
297   return constant_time_eq_8((unsigned)(a), (unsigned)(b));
298 }
299 
300 /* constant_time_select returns (mask & a) | (~mask & b). When |mask| is all 1s
301  * or all 0s (as returned by the methods above), the select methods return
302  * either |a| (if |mask| is nonzero) or |b| (if |mask| is zero). */
constant_time_select(unsigned int mask,unsigned int a,unsigned int b)303 static inline unsigned int constant_time_select(unsigned int mask,
304                                                 unsigned int a, unsigned int b) {
305   return (mask & a) | (~mask & b);
306 }
307 
308 /* constant_time_select_8 acts like |constant_time_select| but operates on
309  * 8-bit values. */
constant_time_select_8(uint8_t mask,uint8_t a,uint8_t b)310 static inline uint8_t constant_time_select_8(uint8_t mask, uint8_t a,
311                                              uint8_t b) {
312   return (uint8_t)(constant_time_select(mask, a, b));
313 }
314 
315 /* constant_time_select_int acts like |constant_time_select| but operates on
316  * ints. */
constant_time_select_int(unsigned int mask,int a,int b)317 static inline int constant_time_select_int(unsigned int mask, int a, int b) {
318   return (int)(constant_time_select(mask, (unsigned)(a), (unsigned)(b)));
319 }
320 
321 
322 /* Thread-safe initialisation. */
323 
324 #if defined(OPENSSL_NO_THREADS)
325 typedef uint32_t CRYPTO_once_t;
326 #define CRYPTO_ONCE_INIT 0
327 #elif defined(OPENSSL_WINDOWS)
328 typedef LONG CRYPTO_once_t;
329 #define CRYPTO_ONCE_INIT 0
330 #else
331 typedef pthread_once_t CRYPTO_once_t;
332 #define CRYPTO_ONCE_INIT PTHREAD_ONCE_INIT
333 #endif
334 
335 /* CRYPTO_once calls |init| exactly once per process. This is thread-safe: if
336  * concurrent threads call |CRYPTO_once| with the same |CRYPTO_once_t| argument
337  * then they will block until |init| completes, but |init| will have only been
338  * called once.
339  *
340  * The |once| argument must be a |CRYPTO_once_t| that has been initialised with
341  * the value |CRYPTO_ONCE_INIT|. */
342 OPENSSL_EXPORT void CRYPTO_once(CRYPTO_once_t *once, void (*init)(void));
343 
344 
345 /* Reference counting. */
346 
347 /* CRYPTO_REFCOUNT_MAX is the value at which the reference count saturates. */
348 #define CRYPTO_REFCOUNT_MAX 0xffffffff
349 
350 /* CRYPTO_refcount_inc atomically increments the value at |*count| unless the
351  * value would overflow. It's safe for multiple threads to concurrently call
352  * this or |CRYPTO_refcount_dec_and_test_zero| on the same
353  * |CRYPTO_refcount_t|. */
354 OPENSSL_EXPORT void CRYPTO_refcount_inc(CRYPTO_refcount_t *count);
355 
356 /* CRYPTO_refcount_dec_and_test_zero tests the value at |*count|:
357  *   if it's zero, it crashes the address space.
358  *   if it's the maximum value, it returns zero.
359  *   otherwise, it atomically decrements it and returns one iff the resulting
360  *       value is zero.
361  *
362  * It's safe for multiple threads to concurrently call this or
363  * |CRYPTO_refcount_inc| on the same |CRYPTO_refcount_t|. */
364 OPENSSL_EXPORT int CRYPTO_refcount_dec_and_test_zero(CRYPTO_refcount_t *count);
365 
366 
367 /* Locks.
368  *
369  * Two types of locks are defined: |CRYPTO_MUTEX|, which can be used in
370  * structures as normal, and |struct CRYPTO_STATIC_MUTEX|, which can be used as
371  * a global lock. A global lock must be initialised to the value
372  * |CRYPTO_STATIC_MUTEX_INIT|.
373  *
374  * |CRYPTO_MUTEX| can appear in public structures and so is defined in
375  * thread.h.
376  *
377  * The global lock is a different type because there's no static initialiser
378  * value on Windows for locks, so global locks have to be coupled with a
379  * |CRYPTO_once_t| to ensure that the lock is setup before use. This is done
380  * automatically by |CRYPTO_STATIC_MUTEX_lock_*|. */
381 
382 #if defined(OPENSSL_NO_THREADS)
383 struct CRYPTO_STATIC_MUTEX {};
384 #define CRYPTO_STATIC_MUTEX_INIT {}
385 #elif defined(OPENSSL_WINDOWS)
386 struct CRYPTO_STATIC_MUTEX {
387   CRYPTO_once_t once;
388   CRITICAL_SECTION lock;
389 };
390 #define CRYPTO_STATIC_MUTEX_INIT { CRYPTO_ONCE_INIT, { 0 } }
391 #else
392 struct CRYPTO_STATIC_MUTEX {
393   pthread_rwlock_t lock;
394 };
395 #define CRYPTO_STATIC_MUTEX_INIT { PTHREAD_RWLOCK_INITIALIZER }
396 #endif
397 
398 /* CRYPTO_MUTEX_init initialises |lock|. If |lock| is a static variable, use a
399  * |CRYPTO_STATIC_MUTEX|. */
400 OPENSSL_EXPORT void CRYPTO_MUTEX_init(CRYPTO_MUTEX *lock);
401 
402 /* CRYPTO_MUTEX_lock_read locks |lock| such that other threads may also have a
403  * read lock, but none may have a write lock. (On Windows, read locks are
404  * actually fully exclusive.) */
405 OPENSSL_EXPORT void CRYPTO_MUTEX_lock_read(CRYPTO_MUTEX *lock);
406 
407 /* CRYPTO_MUTEX_lock_write locks |lock| such that no other thread has any type
408  * of lock on it. */
409 OPENSSL_EXPORT void CRYPTO_MUTEX_lock_write(CRYPTO_MUTEX *lock);
410 
411 /* CRYPTO_MUTEX_unlock unlocks |lock|. */
412 OPENSSL_EXPORT void CRYPTO_MUTEX_unlock(CRYPTO_MUTEX *lock);
413 
414 /* CRYPTO_MUTEX_cleanup releases all resources held by |lock|. */
415 OPENSSL_EXPORT void CRYPTO_MUTEX_cleanup(CRYPTO_MUTEX *lock);
416 
417 /* CRYPTO_STATIC_MUTEX_lock_read locks |lock| such that other threads may also
418  * have a read lock, but none may have a write lock. The |lock| variable does
419  * not need to be initialised by any function, but must have been statically
420  * initialised with |CRYPTO_STATIC_MUTEX_INIT|. */
421 OPENSSL_EXPORT void CRYPTO_STATIC_MUTEX_lock_read(
422     struct CRYPTO_STATIC_MUTEX *lock);
423 
424 /* CRYPTO_STATIC_MUTEX_lock_write locks |lock| such that no other thread has
425  * any type of lock on it.  The |lock| variable does not need to be initialised
426  * by any function, but must have been statically initialised with
427  * |CRYPTO_STATIC_MUTEX_INIT|. */
428 OPENSSL_EXPORT void CRYPTO_STATIC_MUTEX_lock_write(
429     struct CRYPTO_STATIC_MUTEX *lock);
430 
431 /* CRYPTO_STATIC_MUTEX_unlock unlocks |lock|. */
432 OPENSSL_EXPORT void CRYPTO_STATIC_MUTEX_unlock(
433     struct CRYPTO_STATIC_MUTEX *lock);
434 
435 
436 /* Thread local storage. */
437 
438 /* thread_local_data_t enumerates the types of thread-local data that can be
439  * stored. */
440 typedef enum {
441   OPENSSL_THREAD_LOCAL_ERR = 0,
442   OPENSSL_THREAD_LOCAL_RAND,
443   OPENSSL_THREAD_LOCAL_URANDOM_BUF,
444   OPENSSL_THREAD_LOCAL_TEST,
445   NUM_OPENSSL_THREAD_LOCALS,
446 } thread_local_data_t;
447 
448 /* thread_local_destructor_t is the type of a destructor function that will be
449  * called when a thread exits and its thread-local storage needs to be freed. */
450 typedef void (*thread_local_destructor_t)(void *);
451 
452 /* CRYPTO_get_thread_local gets the pointer value that is stored for the
453  * current thread for the given index, or NULL if none has been set. */
454 OPENSSL_EXPORT void *CRYPTO_get_thread_local(thread_local_data_t value);
455 
456 /* CRYPTO_set_thread_local sets a pointer value for the current thread at the
457  * given index. This function should only be called once per thread for a given
458  * |index|: rather than update the pointer value itself, update the data that
459  * is pointed to.
460  *
461  * The destructor function will be called when a thread exits to free this
462  * thread-local data. All calls to |CRYPTO_set_thread_local| with the same
463  * |index| should have the same |destructor| argument. The destructor may be
464  * called with a NULL argument if a thread that never set a thread-local
465  * pointer for |index|, exits. The destructor may be called concurrently with
466  * different arguments.
467  *
468  * This function returns one on success or zero on error. If it returns zero
469  * then |destructor| has been called with |value| already. */
470 OPENSSL_EXPORT int CRYPTO_set_thread_local(
471     thread_local_data_t index, void *value,
472     thread_local_destructor_t destructor);
473 
474 
475 /* ex_data */
476 
477 typedef struct crypto_ex_data_func_st CRYPTO_EX_DATA_FUNCS;
478 
479 /* CRYPTO_EX_DATA_CLASS tracks the ex_indices registered for a type which
480  * supports ex_data. It should defined as a static global within the module
481  * which defines that type. */
482 typedef struct {
483   struct CRYPTO_STATIC_MUTEX lock;
484   STACK_OF(CRYPTO_EX_DATA_FUNCS) *meth;
485   /* num_reserved is one if the ex_data index zero is reserved for legacy
486    * |TYPE_get_app_data| functions. */
487   uint8_t num_reserved;
488 } CRYPTO_EX_DATA_CLASS;
489 
490 #define CRYPTO_EX_DATA_CLASS_INIT {CRYPTO_STATIC_MUTEX_INIT, NULL, 0}
491 #define CRYPTO_EX_DATA_CLASS_INIT_WITH_APP_DATA \
492     {CRYPTO_STATIC_MUTEX_INIT, NULL, 1}
493 
494 /* CRYPTO_get_ex_new_index allocates a new index for |ex_data_class| and writes
495  * it to |*out_index|. Each class of object should provide a wrapper function
496  * that uses the correct |CRYPTO_EX_DATA_CLASS|. It returns one on success and
497  * zero otherwise. */
498 OPENSSL_EXPORT int CRYPTO_get_ex_new_index(CRYPTO_EX_DATA_CLASS *ex_data_class,
499                                            int *out_index, long argl,
500                                            void *argp, CRYPTO_EX_dup *dup_func,
501                                            CRYPTO_EX_free *free_func);
502 
503 /* CRYPTO_set_ex_data sets an extra data pointer on a given object. Each class
504  * of object should provide a wrapper function. */
505 OPENSSL_EXPORT int CRYPTO_set_ex_data(CRYPTO_EX_DATA *ad, int index, void *val);
506 
507 /* CRYPTO_get_ex_data returns an extra data pointer for a given object, or NULL
508  * if no such index exists. Each class of object should provide a wrapper
509  * function. */
510 OPENSSL_EXPORT void *CRYPTO_get_ex_data(const CRYPTO_EX_DATA *ad, int index);
511 
512 /* CRYPTO_new_ex_data initialises a newly allocated |CRYPTO_EX_DATA|. */
513 OPENSSL_EXPORT void CRYPTO_new_ex_data(CRYPTO_EX_DATA *ad);
514 
515 /* CRYPTO_dup_ex_data duplicates |from| into a freshly allocated
516  * |CRYPTO_EX_DATA|, |to|. Both of which are inside objects of the given
517  * class. It returns one on success and zero otherwise. */
518 OPENSSL_EXPORT int CRYPTO_dup_ex_data(CRYPTO_EX_DATA_CLASS *ex_data_class,
519                                       CRYPTO_EX_DATA *to,
520                                       const CRYPTO_EX_DATA *from);
521 
522 /* CRYPTO_free_ex_data frees |ad|, which is embedded inside |obj|, which is an
523  * object of the given class. */
524 OPENSSL_EXPORT void CRYPTO_free_ex_data(CRYPTO_EX_DATA_CLASS *ex_data_class,
525                                         void *obj, CRYPTO_EX_DATA *ad);
526 
527 
528 #if defined(__cplusplus)
529 }  /* extern C */
530 #endif
531 
532 #endif  /* OPENSSL_HEADER_CRYPTO_INTERNAL_H */
533