xref: /dragonfly/crypto/libressl/crypto/ex_data.c (revision f5b1c8a1)
1 /* $OpenBSD: ex_data.c,v 1.17 2014/07/11 08:44:47 jsing Exp $ */
2 
3 /*
4  * Overhaul notes;
5  *
6  * This code is now *mostly* thread-safe. It is now easier to understand in what
7  * ways it is safe and in what ways it is not, which is an improvement. Firstly,
8  * all per-class stacks and index-counters for ex_data are stored in the same
9  * global LHASH table (keyed by class). This hash table uses locking for all
10  * access with the exception of CRYPTO_cleanup_all_ex_data(), which must only be
11  * called when no other threads can possibly race against it (even if it was
12  * locked, the race would mean it's possible the hash table might have been
13  * recreated after the cleanup). As classes can only be added to the hash table,
14  * and within each class, the stack of methods can only be incremented, the
15  * locking mechanics are simpler than they would otherwise be. For example, the
16  * new/dup/free ex_data functions will lock the hash table, copy the method
17  * pointers it needs from the relevant class, then unlock the hash table before
18  * actually applying those method pointers to the task of the new/dup/free
19  * operations. As they can't be removed from the method-stack, only
20  * supplemented, there's no race conditions associated with using them outside
21  * the lock. The get/set_ex_data functions are not locked because they do not
22  * involve this global state at all - they operate directly with a previously
23  * obtained per-class method index and a particular "ex_data" variable. These
24  * variables are usually instantiated per-context (eg. each RSA structure has
25  * one) so locking on read/write access to that variable can be locked locally
26  * if required (eg. using the "RSA" lock to synchronise access to a
27  * per-RSA-structure ex_data variable if required).
28  * [Geoff]
29  */
30 
31 /* Copyright (C) 1995-1998 Eric Young (eay@cryptsoft.com)
32  * All rights reserved.
33  *
34  * This package is an SSL implementation written
35  * by Eric Young (eay@cryptsoft.com).
36  * The implementation was written so as to conform with Netscapes SSL.
37  *
38  * This library is free for commercial and non-commercial use as long as
39  * the following conditions are aheared to.  The following conditions
40  * apply to all code found in this distribution, be it the RC4, RSA,
41  * lhash, DES, etc., code; not just the SSL code.  The SSL documentation
42  * included with this distribution is covered by the same copyright terms
43  * except that the holder is Tim Hudson (tjh@cryptsoft.com).
44  *
45  * Copyright remains Eric Young's, and as such any Copyright notices in
46  * the code are not to be removed.
47  * If this package is used in a product, Eric Young should be given attribution
48  * as the author of the parts of the library used.
49  * This can be in the form of a textual message at program startup or
50  * in documentation (online or textual) provided with the package.
51  *
52  * Redistribution and use in source and binary forms, with or without
53  * modification, are permitted provided that the following conditions
54  * are met:
55  * 1. Redistributions of source code must retain the copyright
56  *    notice, this list of conditions and the following disclaimer.
57  * 2. Redistributions in binary form must reproduce the above copyright
58  *    notice, this list of conditions and the following disclaimer in the
59  *    documentation and/or other materials provided with the distribution.
60  * 3. All advertising materials mentioning features or use of this software
61  *    must display the following acknowledgement:
62  *    "This product includes cryptographic software written by
63  *     Eric Young (eay@cryptsoft.com)"
64  *    The word 'cryptographic' can be left out if the rouines from the library
65  *    being used are not cryptographic related :-).
66  * 4. If you include any Windows specific code (or a derivative thereof) from
67  *    the apps directory (application code) you must include an acknowledgement:
68  *    "This product includes software written by Tim Hudson (tjh@cryptsoft.com)"
69  *
70  * THIS SOFTWARE IS PROVIDED BY ERIC YOUNG ``AS IS'' AND
71  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
72  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
73  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
74  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
75  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
76  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
77  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
78  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
79  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
80  * SUCH DAMAGE.
81  *
82  * The licence and distribution terms for any publically available version or
83  * derivative of this code cannot be changed.  i.e. this code cannot simply be
84  * copied and put under another distribution licence
85  * [including the GNU Public Licence.]
86  */
87 /* ====================================================================
88  * Copyright (c) 1998-2001 The OpenSSL Project.  All rights reserved.
89  *
90  * Redistribution and use in source and binary forms, with or without
91  * modification, are permitted provided that the following conditions
92  * are met:
93  *
94  * 1. Redistributions of source code must retain the above copyright
95  *    notice, this list of conditions and the following disclaimer.
96  *
97  * 2. Redistributions in binary form must reproduce the above copyright
98  *    notice, this list of conditions and the following disclaimer in
99  *    the documentation and/or other materials provided with the
100  *    distribution.
101  *
102  * 3. All advertising materials mentioning features or use of this
103  *    software must display the following acknowledgment:
104  *    "This product includes software developed by the OpenSSL Project
105  *    for use in the OpenSSL Toolkit. (http://www.openssl.org/)"
106  *
107  * 4. The names "OpenSSL Toolkit" and "OpenSSL Project" must not be used to
108  *    endorse or promote products derived from this software without
109  *    prior written permission. For written permission, please contact
110  *    openssl-core@openssl.org.
111  *
112  * 5. Products derived from this software may not be called "OpenSSL"
113  *    nor may "OpenSSL" appear in their names without prior written
114  *    permission of the OpenSSL Project.
115  *
116  * 6. Redistributions of any form whatsoever must retain the following
117  *    acknowledgment:
118  *    "This product includes software developed by the OpenSSL Project
119  *    for use in the OpenSSL Toolkit (http://www.openssl.org/)"
120  *
121  * THIS SOFTWARE IS PROVIDED BY THE OpenSSL PROJECT ``AS IS'' AND ANY
122  * EXPRESSED OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
123  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
124  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE OpenSSL PROJECT OR
125  * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
126  * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
127  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
128  * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
129  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
130  * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
131  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
132  * OF THE POSSIBILITY OF SUCH DAMAGE.
133  * ====================================================================
134  *
135  * This product includes cryptographic software written by Eric Young
136  * (eay@cryptsoft.com).  This product includes software written by Tim
137  * Hudson (tjh@cryptsoft.com).
138  *
139  */
140 
141 #include <openssl/err.h>
142 #include <openssl/lhash.h>
143 
144 /* What an "implementation of ex_data functionality" looks like */
145 struct st_CRYPTO_EX_DATA_IMPL {
146 	/*********************/
147 	/* GLOBAL OPERATIONS */
148 	/* Return a new class index */
149 	int (*cb_new_class)(void);
150 	/* Cleanup all state used by the implementation */
151 	void (*cb_cleanup)(void);
152 	/************************/
153 	/* PER-CLASS OPERATIONS */
154 	/* Get a new method index within a class */
155 	int (*cb_get_new_index)(int class_index, long argl, void *argp,
156 	    CRYPTO_EX_new *new_func, CRYPTO_EX_dup *dup_func,
157 	    CRYPTO_EX_free *free_func);
158 	/* Initialise a new CRYPTO_EX_DATA of a given class */
159 	int (*cb_new_ex_data)(int class_index, void *obj,
160 	    CRYPTO_EX_DATA *ad);
161 	/* Duplicate a CRYPTO_EX_DATA of a given class onto a copy */
162 	int (*cb_dup_ex_data)(int class_index, CRYPTO_EX_DATA *to,
163 	    CRYPTO_EX_DATA *from);
164 	/* Cleanup a CRYPTO_EX_DATA of a given class */
165 	void (*cb_free_ex_data)(int class_index, void *obj,
166 	    CRYPTO_EX_DATA *ad);
167 };
168 
169 /* The implementation we use at run-time */
170 static const CRYPTO_EX_DATA_IMPL *impl = NULL;
171 
172 /* To call "impl" functions, use this macro rather than referring to 'impl' directly, eg.
173  * EX_IMPL(get_new_index)(...);
174 */
175 #define EX_IMPL(a) impl->cb_##a
176 
177 /* Predeclare the "default" ex_data implementation */
178 static int int_new_class(void);
179 static void int_cleanup(void);
180 static int int_get_new_index(int class_index, long argl, void *argp,
181     CRYPTO_EX_new *new_func, CRYPTO_EX_dup *dup_func,
182     CRYPTO_EX_free *free_func);
183 static int int_new_ex_data(int class_index, void *obj,
184     CRYPTO_EX_DATA *ad);
185 static int int_dup_ex_data(int class_index, CRYPTO_EX_DATA *to,
186     CRYPTO_EX_DATA *from);
187 static void int_free_ex_data(int class_index, void *obj,
188     CRYPTO_EX_DATA *ad);
189 
190 static CRYPTO_EX_DATA_IMPL impl_default = {
191 	int_new_class,
192 	int_cleanup,
193 	int_get_new_index,
194 	int_new_ex_data,
195 	int_dup_ex_data,
196 	int_free_ex_data
197 };
198 
199 /* Internal function that checks whether "impl" is set and if not, sets it to
200  * the default. */
201 static void
202 impl_check(void)
203 {
204 	CRYPTO_w_lock(CRYPTO_LOCK_EX_DATA);
205 	if (!impl)
206 		impl = &impl_default;
207 	CRYPTO_w_unlock(CRYPTO_LOCK_EX_DATA);
208 }
209 /* A macro wrapper for impl_check that first uses a non-locked test before
210  * invoking the function (which checks again inside a lock). */
211 #define IMPL_CHECK if(!impl) impl_check();
212 
213 /* API functions to get/set the "ex_data" implementation */
214 const CRYPTO_EX_DATA_IMPL *
215 CRYPTO_get_ex_data_implementation(void)
216 {
217 	IMPL_CHECK
218 	return impl;
219 }
220 
221 int
222 CRYPTO_set_ex_data_implementation(const CRYPTO_EX_DATA_IMPL *i)
223 {
224 	int toret = 0;
225 	CRYPTO_w_lock(CRYPTO_LOCK_EX_DATA);
226 	if (!impl) {
227 		impl = i;
228 		toret = 1;
229 	}
230 	CRYPTO_w_unlock(CRYPTO_LOCK_EX_DATA);
231 	return toret;
232 }
233 
234 /****************************************************************************/
235 /* Interal (default) implementation of "ex_data" support. API functions are
236  * further down. */
237 
238 /* The type that represents what each "class" used to implement locally. A STACK
239  * of CRYPTO_EX_DATA_FUNCS plus a index-counter. The 'class_index' is the global
240  * value representing the class that is used to distinguish these items. */
241 typedef struct st_ex_class_item {
242 	int class_index;
243 	STACK_OF(CRYPTO_EX_DATA_FUNCS) *meth;
244 	int meth_num;
245 } EX_CLASS_ITEM;
246 
247 /* When assigning new class indexes, this is our counter */
248 static int ex_class = CRYPTO_EX_INDEX_USER;
249 
250 /* The global hash table of EX_CLASS_ITEM items */
251 DECLARE_LHASH_OF(EX_CLASS_ITEM);
252 static LHASH_OF(EX_CLASS_ITEM) *ex_data = NULL;
253 
254 /* The callbacks required in the "ex_data" hash table */
255 static unsigned long
256 ex_class_item_hash(const EX_CLASS_ITEM *a)
257 {
258 	return a->class_index;
259 }
260 
261 static IMPLEMENT_LHASH_HASH_FN(ex_class_item, EX_CLASS_ITEM)
262 
263 static int
264 ex_class_item_cmp(const EX_CLASS_ITEM *a, const EX_CLASS_ITEM *b)
265 {
266 	return a->class_index - b->class_index;
267 }
268 
269 static IMPLEMENT_LHASH_COMP_FN(ex_class_item, EX_CLASS_ITEM)
270 
271 /* Internal functions used by the "impl_default" implementation to access the
272  * state */
273 
274 static int
275 ex_data_check(void)
276 {
277 	int toret = 1;
278 	CRYPTO_w_lock(CRYPTO_LOCK_EX_DATA);
279 	if (!ex_data &&
280 	    (ex_data = lh_EX_CLASS_ITEM_new()) == NULL)
281 		toret = 0;
282 	CRYPTO_w_unlock(CRYPTO_LOCK_EX_DATA);
283 	return toret;
284 }
285 /* This macros helps reduce the locking from repeated checks because the
286  * ex_data_check() function checks ex_data again inside a lock. */
287 #define EX_DATA_CHECK(iffail) if(!ex_data && !ex_data_check()) {iffail}
288 
289 /* This "inner" callback is used by the callback function that follows it */
290 static void
291 def_cleanup_util_cb(CRYPTO_EX_DATA_FUNCS *funcs)
292 {
293 	free(funcs);
294 }
295 
296 /* This callback is used in lh_doall to destroy all EX_CLASS_ITEM values from
297  * "ex_data" prior to the ex_data hash table being itself destroyed. Doesn't do
298  * any locking. */
299 static void
300 def_cleanup_cb(void *a_void)
301 {
302 	EX_CLASS_ITEM *item = (EX_CLASS_ITEM *)a_void;
303 	sk_CRYPTO_EX_DATA_FUNCS_pop_free(item->meth, def_cleanup_util_cb);
304 	free(item);
305 }
306 
307 /* Return the EX_CLASS_ITEM from the "ex_data" hash table that corresponds to a
308  * given class. Handles locking. */
309 static EX_CLASS_ITEM *
310 def_get_class(int class_index)
311 {
312 	EX_CLASS_ITEM d, *p, *gen;
313 	EX_DATA_CHECK(return NULL;)
314 	d.class_index = class_index;
315 	CRYPTO_w_lock(CRYPTO_LOCK_EX_DATA);
316 	p = lh_EX_CLASS_ITEM_retrieve(ex_data, &d);
317 	if (!p) {
318 		gen = malloc(sizeof(EX_CLASS_ITEM));
319 		if (gen) {
320 			gen->class_index = class_index;
321 			gen->meth_num = 0;
322 			gen->meth = sk_CRYPTO_EX_DATA_FUNCS_new_null();
323 			if (!gen->meth)
324 				free(gen);
325 			else {
326 				/* Because we're inside the ex_data lock, the
327 				 * return value from the insert will be NULL */
328 				(void)lh_EX_CLASS_ITEM_insert(ex_data, gen);
329 				p = gen;
330 			}
331 		}
332 	}
333 	CRYPTO_w_unlock(CRYPTO_LOCK_EX_DATA);
334 	if (!p)
335 		CRYPTOerr(CRYPTO_F_DEF_GET_CLASS, ERR_R_MALLOC_FAILURE);
336 	return p;
337 }
338 
339 /* Add a new method to the given EX_CLASS_ITEM and return the corresponding
340  * index (or -1 for error). Handles locking. */
341 static int
342 def_add_index(EX_CLASS_ITEM *item, long argl, void *argp,
343     CRYPTO_EX_new *new_func, CRYPTO_EX_dup *dup_func, CRYPTO_EX_free *free_func)
344 {
345 	int toret = -1;
346 	CRYPTO_EX_DATA_FUNCS *a = malloc(sizeof(CRYPTO_EX_DATA_FUNCS));
347 
348 	if (!a) {
349 		CRYPTOerr(CRYPTO_F_DEF_ADD_INDEX, ERR_R_MALLOC_FAILURE);
350 		return -1;
351 	}
352 	a->argl = argl;
353 	a->argp = argp;
354 	a->new_func = new_func;
355 	a->dup_func = dup_func;
356 	a->free_func = free_func;
357 	CRYPTO_w_lock(CRYPTO_LOCK_EX_DATA);
358 	while (sk_CRYPTO_EX_DATA_FUNCS_num(item->meth) <= item->meth_num) {
359 		if (!sk_CRYPTO_EX_DATA_FUNCS_push(item->meth, NULL)) {
360 			CRYPTOerr(CRYPTO_F_DEF_ADD_INDEX, ERR_R_MALLOC_FAILURE);
361 			free(a);
362 			goto err;
363 		}
364 	}
365 	toret = item->meth_num++;
366 	(void)sk_CRYPTO_EX_DATA_FUNCS_set(item->meth, toret, a);
367 err:
368 	CRYPTO_w_unlock(CRYPTO_LOCK_EX_DATA);
369 	return toret;
370 }
371 
372 /**************************************************************/
373 /* The functions in the default CRYPTO_EX_DATA_IMPL structure */
374 
375 static int
376 int_new_class(void)
377 {
378 	int toret;
379 
380 	CRYPTO_w_lock(CRYPTO_LOCK_EX_DATA);
381 	toret = ex_class++;
382 	CRYPTO_w_unlock(CRYPTO_LOCK_EX_DATA);
383 	return toret;
384 }
385 
386 static void
387 int_cleanup(void)
388 {
389 	EX_DATA_CHECK(return;)
390 	lh_EX_CLASS_ITEM_doall(ex_data, def_cleanup_cb);
391 	lh_EX_CLASS_ITEM_free(ex_data);
392 	ex_data = NULL;
393 	impl = NULL;
394 }
395 
396 static int
397 int_get_new_index(int class_index, long argl, void *argp,
398     CRYPTO_EX_new *new_func, CRYPTO_EX_dup *dup_func,
399     CRYPTO_EX_free *free_func)
400 {
401 	EX_CLASS_ITEM *item = def_get_class(class_index);
402 
403 	if (!item)
404 		return -1;
405 	return def_add_index(item, argl, argp, new_func, dup_func, free_func);
406 }
407 
408 /* Thread-safe by copying a class's array of "CRYPTO_EX_DATA_FUNCS" entries in
409  * the lock, then using them outside the lock. NB: Thread-safety only applies to
410  * the global "ex_data" state (ie. class definitions), not thread-safe on 'ad'
411  * itself. */
412 static int
413 int_new_ex_data(int class_index, void *obj, CRYPTO_EX_DATA *ad)
414 {
415 	int mx, i;
416 	void *ptr;
417 	CRYPTO_EX_DATA_FUNCS **storage = NULL;
418 	EX_CLASS_ITEM *item = def_get_class(class_index);
419 
420 	if (!item)
421 		/* error is already set */
422 		return 0;
423 	ad->sk = NULL;
424 	CRYPTO_r_lock(CRYPTO_LOCK_EX_DATA);
425 	mx = sk_CRYPTO_EX_DATA_FUNCS_num(item->meth);
426 	if (mx > 0) {
427 		storage = reallocarray(NULL, mx, sizeof(CRYPTO_EX_DATA_FUNCS*));
428 		if (!storage)
429 			goto skip;
430 		for (i = 0; i < mx; i++)
431 			storage[i] = sk_CRYPTO_EX_DATA_FUNCS_value(
432 			    item->meth, i);
433 	}
434 skip:
435 	CRYPTO_r_unlock(CRYPTO_LOCK_EX_DATA);
436 	if ((mx > 0) && !storage) {
437 		CRYPTOerr(CRYPTO_F_INT_NEW_EX_DATA, ERR_R_MALLOC_FAILURE);
438 		return 0;
439 	}
440 	for (i = 0; i < mx; i++) {
441 		if (storage[i] && storage[i]->new_func) {
442 			ptr = CRYPTO_get_ex_data(ad, i);
443 			storage[i]->new_func(obj, ptr, ad, i,
444 			    storage[i]->argl, storage[i]->argp);
445 		}
446 	}
447 	free(storage);
448 	return 1;
449 }
450 
451 /* Same thread-safety notes as for "int_new_ex_data" */
452 static int
453 int_dup_ex_data(int class_index, CRYPTO_EX_DATA *to, CRYPTO_EX_DATA *from)
454 {
455 	int mx, j, i;
456 	char *ptr;
457 	CRYPTO_EX_DATA_FUNCS **storage = NULL;
458 	EX_CLASS_ITEM *item;
459 
460 	if (!from->sk)
461 		/* 'to' should be "blank" which *is* just like 'from' */
462 		return 1;
463 	if ((item = def_get_class(class_index)) == NULL)
464 		return 0;
465 	CRYPTO_r_lock(CRYPTO_LOCK_EX_DATA);
466 	mx = sk_CRYPTO_EX_DATA_FUNCS_num(item->meth);
467 	j = sk_void_num(from->sk);
468 	if (j < mx)
469 		mx = j;
470 	if (mx > 0) {
471 		storage = reallocarray(NULL, mx, sizeof(CRYPTO_EX_DATA_FUNCS*));
472 		if (!storage)
473 			goto skip;
474 		for (i = 0; i < mx; i++)
475 			storage[i] = sk_CRYPTO_EX_DATA_FUNCS_value(
476 			    item->meth, i);
477 	}
478 skip:
479 	CRYPTO_r_unlock(CRYPTO_LOCK_EX_DATA);
480 	if ((mx > 0) && !storage) {
481 		CRYPTOerr(CRYPTO_F_INT_DUP_EX_DATA, ERR_R_MALLOC_FAILURE);
482 		return 0;
483 	}
484 	for (i = 0; i < mx; i++) {
485 		ptr = CRYPTO_get_ex_data(from, i);
486 		if (storage[i] && storage[i]->dup_func)
487 			storage[i]->dup_func(to, from, &ptr, i,
488 			    storage[i]->argl, storage[i]->argp);
489 		CRYPTO_set_ex_data(to, i, ptr);
490 	}
491 	free(storage);
492 	return 1;
493 }
494 
495 /* Same thread-safety notes as for "int_new_ex_data" */
496 static void
497 int_free_ex_data(int class_index, void *obj, CRYPTO_EX_DATA *ad)
498 {
499 	int mx, i;
500 	EX_CLASS_ITEM *item;
501 	void *ptr;
502 	CRYPTO_EX_DATA_FUNCS **storage = NULL;
503 	if ((item = def_get_class(class_index)) == NULL)
504 		return;
505 	CRYPTO_r_lock(CRYPTO_LOCK_EX_DATA);
506 	mx = sk_CRYPTO_EX_DATA_FUNCS_num(item->meth);
507 	if (mx > 0) {
508 		storage = reallocarray(NULL, mx, sizeof(CRYPTO_EX_DATA_FUNCS*));
509 		if (!storage)
510 			goto skip;
511 		for (i = 0; i < mx; i++)
512 			storage[i] = sk_CRYPTO_EX_DATA_FUNCS_value(
513 			    item->meth, i);
514 	}
515 skip:
516 	CRYPTO_r_unlock(CRYPTO_LOCK_EX_DATA);
517 	if ((mx > 0) && !storage) {
518 		CRYPTOerr(CRYPTO_F_INT_FREE_EX_DATA, ERR_R_MALLOC_FAILURE);
519 		return;
520 	}
521 	for (i = 0; i < mx; i++) {
522 		if (storage[i] && storage[i]->free_func) {
523 			ptr = CRYPTO_get_ex_data(ad, i);
524 			storage[i]->free_func(obj, ptr, ad, i,
525 			    storage[i]->argl, storage[i]->argp);
526 		}
527 	}
528 	free(storage);
529 	if (ad->sk) {
530 		sk_void_free(ad->sk);
531 		ad->sk = NULL;
532 	}
533 }
534 
535 /********************************************************************/
536 /* API functions that defer all "state" operations to the "ex_data"
537  * implementation we have set. */
538 
539 /* Obtain an index for a new class (not the same as getting a new index within
540  * an existing class - this is actually getting a new *class*) */
541 int
542 CRYPTO_ex_data_new_class(void)
543 {
544 	IMPL_CHECK
545 	return EX_IMPL(new_class)();
546 }
547 
548 /* Release all "ex_data" state to prevent memory leaks. This can't be made
549  * thread-safe without overhauling a lot of stuff, and shouldn't really be
550  * called under potential race-conditions anyway (it's for program shutdown
551  * after all). */
552 void
553 CRYPTO_cleanup_all_ex_data(void)
554 {
555 	IMPL_CHECK
556 	EX_IMPL(cleanup)();
557 }
558 
559 /* Inside an existing class, get/register a new index. */
560 int
561 CRYPTO_get_ex_new_index(int class_index, long argl, void *argp,
562     CRYPTO_EX_new *new_func, CRYPTO_EX_dup *dup_func, CRYPTO_EX_free *free_func)
563 {
564 	int ret = -1;
565 
566 	IMPL_CHECK
567 	ret = EX_IMPL(get_new_index)(class_index,
568 	    argl, argp, new_func, dup_func, free_func);
569 	return ret;
570 }
571 
572 /* Initialise a new CRYPTO_EX_DATA for use in a particular class - including
573  * calling new() callbacks for each index in the class used by this variable */
574 int
575 CRYPTO_new_ex_data(int class_index, void *obj, CRYPTO_EX_DATA *ad)
576 {
577 	IMPL_CHECK
578 	return EX_IMPL(new_ex_data)(class_index, obj, ad);
579 }
580 
581 /* Duplicate a CRYPTO_EX_DATA variable - including calling dup() callbacks for
582  * each index in the class used by this variable */
583 int
584 CRYPTO_dup_ex_data(int class_index, CRYPTO_EX_DATA *to, CRYPTO_EX_DATA *from)
585 {
586 	IMPL_CHECK
587 	return EX_IMPL(dup_ex_data)(class_index, to, from);
588 }
589 
590 /* Cleanup a CRYPTO_EX_DATA variable - including calling free() callbacks for
591  * each index in the class used by this variable */
592 void
593 CRYPTO_free_ex_data(int class_index, void *obj, CRYPTO_EX_DATA *ad)
594 {
595 	IMPL_CHECK
596 	EX_IMPL(free_ex_data)(class_index, obj, ad);
597 }
598 
599 /* For a given CRYPTO_EX_DATA variable, set the value corresponding to a
600  * particular index in the class used by this variable */
601 int
602 CRYPTO_set_ex_data(CRYPTO_EX_DATA *ad, int idx, void *val)
603 {
604 	int i;
605 
606 	if (ad->sk == NULL) {
607 		if ((ad->sk = sk_void_new_null()) == NULL) {
608 			CRYPTOerr(CRYPTO_F_CRYPTO_SET_EX_DATA,
609 			    ERR_R_MALLOC_FAILURE);
610 			return (0);
611 		}
612 	}
613 	i = sk_void_num(ad->sk);
614 
615 	while (i <= idx) {
616 		if (!sk_void_push(ad->sk, NULL)) {
617 			CRYPTOerr(CRYPTO_F_CRYPTO_SET_EX_DATA,
618 			    ERR_R_MALLOC_FAILURE);
619 			return (0);
620 		}
621 		i++;
622 	}
623 	sk_void_set(ad->sk, idx, val);
624 	return (1);
625 }
626 
627 /* For a given CRYPTO_EX_DATA_ variable, get the value corresponding to a
628  * particular index in the class used by this variable */
629 void *
630 CRYPTO_get_ex_data(const CRYPTO_EX_DATA *ad, int idx)
631 {
632 	if (ad->sk == NULL)
633 		return (0);
634 	else if (idx >= sk_void_num(ad->sk))
635 		return (0);
636 	else
637 		return (sk_void_value(ad->sk, idx));
638 }
639