lib/libcrypto/ex_data.c

   1 /* $OpenBSD: ex_data.c,v 1.20 2018/03/17 16:20:01 beck 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         if (!OPENSSL_init_crypto(0, NULL))
 316                 return NULL;
 317         CRYPTO_w_lock(CRYPTO_LOCK_EX_DATA);
 318         p = lh_EX_CLASS_ITEM_retrieve(ex_data, &d);
 319         if (!p) {
 320                 gen = malloc(sizeof(EX_CLASS_ITEM));
 321                 if (gen) {
 322                         gen->class_index = class_index;
 323                         gen->meth_num = 0;
 324                         gen->meth = sk_CRYPTO_EX_DATA_FUNCS_new_null();
 325                         if (!gen->meth)
 326                                 free(gen);
 327                         else {
 328                                 /* Because we're inside the ex_data lock, the
 329                                  * return value from the insert will be NULL */
 330                                 (void)lh_EX_CLASS_ITEM_insert(ex_data, gen);
 331                                 p = gen;
 332                         }
 333                 }
 334         }
 335         CRYPTO_w_unlock(CRYPTO_LOCK_EX_DATA);
 336         if (!p)
 337                 CRYPTOerror(ERR_R_MALLOC_FAILURE);
 338         return p;
 339 }
 340
 341 /* Add a new method to the given EX_CLASS_ITEM and return the corresponding
 342  * index (or -1 for error). Handles locking. */
 343 static int
 344 def_add_index(EX_CLASS_ITEM *item, long argl, void *argp,
 345     CRYPTO_EX_new *new_func, CRYPTO_EX_dup *dup_func, CRYPTO_EX_free *free_func)
 346 {
 347         int toret = -1;
 348         CRYPTO_EX_DATA_FUNCS *a = malloc(sizeof(CRYPTO_EX_DATA_FUNCS));
 349
 350         if (!a) {
 351                 CRYPTOerror(ERR_R_MALLOC_FAILURE);
 352                 return -1;
 353         }
 354         a->argl = argl;
 355         a->argp = argp;
 356         a->new_func = new_func;
 357         a->dup_func = dup_func;
 358         a->free_func = free_func;
 359         CRYPTO_w_lock(CRYPTO_LOCK_EX_DATA);
 360         while (sk_CRYPTO_EX_DATA_FUNCS_num(item->meth) <= item->meth_num) {
 361                 if (!sk_CRYPTO_EX_DATA_FUNCS_push(item->meth, NULL)) {
 362                         CRYPTOerror(ERR_R_MALLOC_FAILURE);
 363                         free(a);
 364                         goto err;
 365                 }
 366         }
 367         toret = item->meth_num++;
 368         (void)sk_CRYPTO_EX_DATA_FUNCS_set(item->meth, toret, a);
 369 err:
 370         CRYPTO_w_unlock(CRYPTO_LOCK_EX_DATA);
 371         return toret;
 372 }
 373
 374 /**************************************************************/
 375 /* The functions in the default CRYPTO_EX_DATA_IMPL structure */
 376
 377 static int
 378 int_new_class(void)
 379 {
 380         int toret;
 381
 382         CRYPTO_w_lock(CRYPTO_LOCK_EX_DATA);
 383         toret = ex_class++;
 384         CRYPTO_w_unlock(CRYPTO_LOCK_EX_DATA);
 385         return toret;
 386 }
 387
 388 static void
 389 int_cleanup(void)
 390 {
 391         EX_DATA_CHECK(return;)
 392         lh_EX_CLASS_ITEM_doall(ex_data, def_cleanup_cb);
 393         lh_EX_CLASS_ITEM_free(ex_data);
 394         ex_data = NULL;
 395         impl = NULL;
 396 }
 397
 398 static int
 399 int_get_new_index(int class_index, long argl, void *argp,
 400     CRYPTO_EX_new *new_func, CRYPTO_EX_dup *dup_func,
 401     CRYPTO_EX_free *free_func)
 402 {
 403         EX_CLASS_ITEM *item = def_get_class(class_index);
 404
 405         if (!item)
 406                 return -1;
 407         return def_add_index(item, argl, argp, new_func, dup_func, free_func);
 408 }
 409
 410 /* Thread-safe by copying a class's array of "CRYPTO_EX_DATA_FUNCS" entries in
 411  * the lock, then using them outside the lock. NB: Thread-safety only applies to
 412  * the global "ex_data" state (ie. class definitions), not thread-safe on 'ad'
 413  * itself. */
 414 static int
 415 int_new_ex_data(int class_index, void *obj, CRYPTO_EX_DATA *ad)
 416 {
 417         int mx, i;
 418         void *ptr;
 419         CRYPTO_EX_DATA_FUNCS **storage = NULL;
 420         EX_CLASS_ITEM *item = def_get_class(class_index);
 421
 422         if (!item)
 423                 /* error is already set */
 424                 return 0;
 425         ad->sk = NULL;
 426         CRYPTO_r_lock(CRYPTO_LOCK_EX_DATA);
 427         mx = sk_CRYPTO_EX_DATA_FUNCS_num(item->meth);
 428         if (mx > 0) {
 429                 storage = reallocarray(NULL, mx, sizeof(CRYPTO_EX_DATA_FUNCS*));
 430                 if (!storage)
 431                         goto skip;
 432                 for (i = 0; i < mx; i++)
 433                         storage[i] = sk_CRYPTO_EX_DATA_FUNCS_value(
 434                             item->meth, i);
 435         }
 436 skip:
 437         CRYPTO_r_unlock(CRYPTO_LOCK_EX_DATA);
 438         if ((mx > 0) && !storage) {
 439                 CRYPTOerror(ERR_R_MALLOC_FAILURE);
 440                 return 0;
 441         }
 442         for (i = 0; i < mx; i++) {
 443                 if (storage[i] && storage[i]->new_func) {
 444                         ptr = CRYPTO_get_ex_data(ad, i);
 445                         storage[i]->new_func(obj, ptr, ad, i,
 446                             storage[i]->argl, storage[i]->argp);
 447                 }
 448         }
 449         free(storage);
 450         return 1;
 451 }
 452
 453 /* Same thread-safety notes as for "int_new_ex_data" */
 454 static int
 455 int_dup_ex_data(int class_index, CRYPTO_EX_DATA *to, CRYPTO_EX_DATA *from)
 456 {
 457         int mx, j, i;
 458         char *ptr;
 459         CRYPTO_EX_DATA_FUNCS **storage = NULL;
 460         EX_CLASS_ITEM *item;
 461
 462         if (!from->sk)
 463                 /* 'to' should be "blank" which *is* just like 'from' */
 464                 return 1;
 465         if ((item = def_get_class(class_index)) == NULL)
 466                 return 0;
 467         CRYPTO_r_lock(CRYPTO_LOCK_EX_DATA);
 468         mx = sk_CRYPTO_EX_DATA_FUNCS_num(item->meth);
 469         j = sk_void_num(from->sk);
 470         if (j < mx)
 471                 mx = j;
 472         if (mx > 0) {
 473                 storage = reallocarray(NULL, mx, sizeof(CRYPTO_EX_DATA_FUNCS*));
 474                 if (!storage)
 475                         goto skip;
 476                 for (i = 0; i < mx; i++)
 477                         storage[i] = sk_CRYPTO_EX_DATA_FUNCS_value(
 478                             item->meth, i);
 479         }
 480 skip:
 481         CRYPTO_r_unlock(CRYPTO_LOCK_EX_DATA);
 482         if ((mx > 0) && !storage) {
 483                 CRYPTOerror(ERR_R_MALLOC_FAILURE);
 484                 return 0;
 485         }
 486         for (i = 0; i < mx; i++) {
 487                 ptr = CRYPTO_get_ex_data(from, i);
 488                 if (storage[i] && storage[i]->dup_func)
 489                         storage[i]->dup_func(to, from, &ptr, i,
 490                             storage[i]->argl, storage[i]->argp);
 491                 CRYPTO_set_ex_data(to, i, ptr);
 492         }
 493         free(storage);
 494         return 1;
 495 }
 496
 497 /* Same thread-safety notes as for "int_new_ex_data" */
 498 static void
 499 int_free_ex_data(int class_index, void *obj, CRYPTO_EX_DATA *ad)
 500 {
 501         int mx, i;
 502         EX_CLASS_ITEM *item;
 503         void *ptr;
 504         CRYPTO_EX_DATA_FUNCS **storage = NULL;
 505
 506         if ((item = def_get_class(class_index)) == NULL)
 507                 return;
 508         CRYPTO_r_lock(CRYPTO_LOCK_EX_DATA);
 509         mx = sk_CRYPTO_EX_DATA_FUNCS_num(item->meth);
 510         if (mx > 0) {
 511                 storage = reallocarray(NULL, mx, sizeof(CRYPTO_EX_DATA_FUNCS*));
 512                 if (!storage)
 513                         goto skip;
 514                 for (i = 0; i < mx; i++)
 515                         storage[i] = sk_CRYPTO_EX_DATA_FUNCS_value(
 516                             item->meth, i);
 517         }
 518 skip:
 519         CRYPTO_r_unlock(CRYPTO_LOCK_EX_DATA);
 520         if ((mx > 0) && !storage) {
 521                 CRYPTOerror(ERR_R_MALLOC_FAILURE);
 522                 return;
 523         }
 524         for (i = 0; i < mx; i++) {
 525                 if (storage[i] && storage[i]->free_func) {
 526                         ptr = CRYPTO_get_ex_data(ad, i);
 527                         storage[i]->free_func(obj, ptr, ad, i,
 528                             storage[i]->argl, storage[i]->argp);
 529                 }
 530         }
 531         free(storage);
 532         if (ad->sk) {
 533                 sk_void_free(ad->sk);
 534                 ad->sk = NULL;
 535         }
 536 }
 537
 538 /********************************************************************/
 539 /* API functions that defer all "state" operations to the "ex_data"
 540  * implementation we have set. */
 541
 542 /* Obtain an index for a new class (not the same as getting a new index within
 543  * an existing class - this is actually getting a new *class*) */
 544 int
 545 CRYPTO_ex_data_new_class(void)
 546 {
 547         IMPL_CHECK
 548         return EX_IMPL(new_class)();
 549 }
 550
 551 /* Release all "ex_data" state to prevent memory leaks. This can't be made
 552  * thread-safe without overhauling a lot of stuff, and shouldn't really be
 553  * called under potential race-conditions anyway (it's for program shutdown
 554  * after all). */
 555 void
 556 CRYPTO_cleanup_all_ex_data(void)
 557 {
 558         IMPL_CHECK
 559         EX_IMPL(cleanup)();
 560 }
 561
 562 /* Inside an existing class, get/register a new index. */
 563 int
 564 CRYPTO_get_ex_new_index(int class_index, long argl, void *argp,
 565     CRYPTO_EX_new *new_func, CRYPTO_EX_dup *dup_func, CRYPTO_EX_free *free_func)
 566 {
 567         int ret = -1;
 568
 569         IMPL_CHECK
 570         ret = EX_IMPL(get_new_index)(class_index,
 571             argl, argp, new_func, dup_func, free_func);
 572         return ret;
 573 }
 574
 575 /* Initialise a new CRYPTO_EX_DATA for use in a particular class - including
 576  * calling new() callbacks for each index in the class used by this variable */
 577 int
 578 CRYPTO_new_ex_data(int class_index, void *obj, CRYPTO_EX_DATA *ad)
 579 {
 580         IMPL_CHECK
 581         return EX_IMPL(new_ex_data)(class_index, obj, ad);
 582 }
 583
 584 /* Duplicate a CRYPTO_EX_DATA variable - including calling dup() callbacks for
 585  * each index in the class used by this variable */
 586 int
 587 CRYPTO_dup_ex_data(int class_index, CRYPTO_EX_DATA *to, CRYPTO_EX_DATA *from)
 588 {
 589         IMPL_CHECK
 590         return EX_IMPL(dup_ex_data)(class_index, to, from);
 591 }
 592
 593 /* Cleanup a CRYPTO_EX_DATA variable - including calling free() callbacks for
 594  * each index in the class used by this variable */
 595 void
 596 CRYPTO_free_ex_data(int class_index, void *obj, CRYPTO_EX_DATA *ad)
 597 {
 598         IMPL_CHECK
 599         EX_IMPL(free_ex_data)(class_index, obj, ad);
 600 }
 601
 602 /* For a given CRYPTO_EX_DATA variable, set the value corresponding to a
 603  * particular index in the class used by this variable */
 604 int
 605 CRYPTO_set_ex_data(CRYPTO_EX_DATA *ad, int idx, void *val)
 606 {
 607         int i;
 608
 609         if (ad->sk == NULL) {
 610                 if ((ad->sk = sk_void_new_null()) == NULL) {
 611                         CRYPTOerror(ERR_R_MALLOC_FAILURE);
 612                         return (0);
 613                 }
 614         }
 615         i = sk_void_num(ad->sk);
 616
 617         while (i <= idx) {
 618                 if (!sk_void_push(ad->sk, NULL)) {
 619                         CRYPTOerror(ERR_R_MALLOC_FAILURE);
 620                         return (0);
 621                 }
 622                 i++;
 623         }
 624         sk_void_set(ad->sk, idx, val);
 625         return (1);
 626 }
 627
 628 /* For a given CRYPTO_EX_DATA_ variable, get the value corresponding to a
 629  * particular index in the class used by this variable */
 630 void *
 631 CRYPTO_get_ex_data(const CRYPTO_EX_DATA *ad, int idx)
 632 {
 633         if (ad->sk == NULL)
 634                 return (0);
 635         else if (idx >= sk_void_num(ad->sk))
 636                 return (0);
 637         else
 638                 return (sk_void_value(ad->sk, idx));
 639 }