crypto/ex_data.c

   1 /* crypto/ex_data.c */
   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 "cryptlib.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, CRYPTO_EX_DATA *ad);
 160     /* Duplicate a CRYPTO_EX_DATA of a given class onto a copy */
 161     int (*cb_dup_ex_data) (int class_index, CRYPTO_EX_DATA *to,
 162                            CRYPTO_EX_DATA *from);
 163     /* Cleanup a CRYPTO_EX_DATA of a given class */
 164     void (*cb_free_ex_data) (int class_index, void *obj, CRYPTO_EX_DATA *ad);
 165 };
 166
 167 /* The implementation we use at run-time */
 168 static const CRYPTO_EX_DATA_IMPL *impl = NULL;
 169
 170 /*
 171  * To call "impl" functions, use this macro rather than referring to 'impl'
 172  * directly, eg. EX_IMPL(get_new_index)(...);
 173  */
 174 #define EX_IMPL(a) impl->cb_##a
 175
 176 /* Predeclare the "default" ex_data implementation */
 177 static int int_new_class(void);
 178 static void int_cleanup(void);
 179 static int int_get_new_index(int class_index, long argl, void *argp,
 180                              CRYPTO_EX_new *new_func, CRYPTO_EX_dup *dup_func,
 181                              CRYPTO_EX_free *free_func);
 182 static int int_new_ex_data(int class_index, void *obj, CRYPTO_EX_DATA *ad);
 183 static int int_dup_ex_data(int class_index, CRYPTO_EX_DATA *to,
 184                            CRYPTO_EX_DATA *from);
 185 static void int_free_ex_data(int class_index, void *obj, CRYPTO_EX_DATA *ad);
 186 static CRYPTO_EX_DATA_IMPL impl_default = {
 187     int_new_class,
 188     int_cleanup,
 189     int_get_new_index,
 190     int_new_ex_data,
 191     int_dup_ex_data,
 192     int_free_ex_data
 193 };
 194
 195 /*
 196  * Internal function that checks whether "impl" is set and if not, sets it to
 197  * the default.
 198  */
 199 static void impl_check(void)
 200 {
 201     CRYPTO_w_lock(CRYPTO_LOCK_EX_DATA);
 202     if (!impl)
 203         impl = &impl_default;
 204     CRYPTO_w_unlock(CRYPTO_LOCK_EX_DATA);
 205 }
 206
 207 /*
 208  * A macro wrapper for impl_check that first uses a non-locked test before
 209  * invoking the function (which checks again inside a lock).
 210  */
 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 *CRYPTO_get_ex_data_implementation(void)
 215 {
 216     IMPL_CHECK return impl;
 217 }
 218
 219 int CRYPTO_set_ex_data_implementation(const CRYPTO_EX_DATA_IMPL *i)
 220 {
 221     int toret = 0;
 222     CRYPTO_w_lock(CRYPTO_LOCK_EX_DATA);
 223     if (!impl) {
 224         impl = i;
 225         toret = 1;
 226     }
 227     CRYPTO_w_unlock(CRYPTO_LOCK_EX_DATA);
 228     return toret;
 229 }
 230
 231 /****************************************************************************/
 232 /*
 233  * Interal (default) implementation of "ex_data" support. API functions are
 234  * further down.
 235  */
 236
 237 /*
 238  * The type that represents what each "class" used to implement locally. A
 239  * STACK of CRYPTO_EX_DATA_FUNCS plus a index-counter. The 'class_index' is
 240  * the global value representing the class that is used to distinguish these
 241  * items.
 242  */
 243 typedef struct st_ex_class_item {
 244     int class_index;
 245     STACK_OF(CRYPTO_EX_DATA_FUNCS) *meth;
 246     int meth_num;
 247 } EX_CLASS_ITEM;
 248
 249 /* When assigning new class indexes, this is our counter */
 250 static int ex_class = CRYPTO_EX_INDEX_USER;
 251
 252 /* The global hash table of EX_CLASS_ITEM items */
 253 DECLARE_LHASH_OF(EX_CLASS_ITEM);
 254 static LHASH_OF(EX_CLASS_ITEM) *ex_data = NULL;
 255
 256 /* The callbacks required in the "ex_data" hash table */
 257 static unsigned long ex_class_item_hash(const EX_CLASS_ITEM *a)
 258 {
 259     return a->class_index;
 260 }
 261
 262 static IMPLEMENT_LHASH_HASH_FN(ex_class_item, EX_CLASS_ITEM)
 263
 264 static int 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 /*
 272  * Internal functions used by the "impl_default" implementation to access the
 273  * state
 274  */
 275 static int ex_data_check(void)
 276 {
 277     int toret = 1;
 278     CRYPTO_w_lock(CRYPTO_LOCK_EX_DATA);
 279     if (!ex_data && (ex_data = lh_EX_CLASS_ITEM_new()) == NULL)
 280         toret = 0;
 281     CRYPTO_w_unlock(CRYPTO_LOCK_EX_DATA);
 282     return toret;
 283 }
 284
 285 /*
 286  * This macros helps reduce the locking from repeated checks because the
 287  * ex_data_check() function checks ex_data again inside a lock.
 288  */
 289 #define EX_DATA_CHECK(iffail) if(!ex_data && !ex_data_check()) {iffail}
 290
 291 /* This "inner" callback is used by the callback function that follows it */
 292 static void def_cleanup_util_cb(CRYPTO_EX_DATA_FUNCS *funcs)
 293 {
 294     OPENSSL_free(funcs);
 295 }
 296
 297 /*
 298  * This callback is used in lh_doall to destroy all EX_CLASS_ITEM values from
 299  * "ex_data" prior to the ex_data hash table being itself destroyed. Doesn't
 300  * do any locking.
 301  */
 302 static void def_cleanup_cb(void *a_void)
 303 {
 304     EX_CLASS_ITEM *item = (EX_CLASS_ITEM *)a_void;
 305     sk_CRYPTO_EX_DATA_FUNCS_pop_free(item->meth, def_cleanup_util_cb);
 306     OPENSSL_free(item);
 307 }
 308
 309 /*
 310  * Return the EX_CLASS_ITEM from the "ex_data" hash table that corresponds to
 311  * a given class. Handles locking.
 312  */
 313 static EX_CLASS_ITEM *def_get_class(int class_index)
 314 {
 315     EX_CLASS_ITEM d, *p, *gen;
 316     EX_DATA_CHECK(return NULL;)
 317         d.class_index = class_index;
 318     CRYPTO_w_lock(CRYPTO_LOCK_EX_DATA);
 319     p = lh_EX_CLASS_ITEM_retrieve(ex_data, &d);
 320     if (!p) {
 321         gen = OPENSSL_malloc(sizeof(EX_CLASS_ITEM));
 322         if (gen) {
 323             gen->class_index = class_index;
 324             gen->meth_num = 0;
 325             gen->meth = sk_CRYPTO_EX_DATA_FUNCS_new_null();
 326             if (!gen->meth)
 327                 OPENSSL_free(gen);
 328             else {
 329                 /*
 330                  * Because we're inside the ex_data lock, the return value
 331                  * from the insert will be NULL
 332                  */
 333                 (void)lh_EX_CLASS_ITEM_insert(ex_data, gen);
 334                 p = lh_EX_CLASS_ITEM_retrieve(ex_data, &d);
 335                 if (p != gen) {
 336                     sk_CRYPTO_EX_DATA_FUNCS_free(gen->meth);
 337                     OPENSSL_free(gen);
 338                 }
 339             }
 340         }
 341     }
 342     CRYPTO_w_unlock(CRYPTO_LOCK_EX_DATA);
 343     if (!p)
 344         CRYPTOerr(CRYPTO_F_DEF_GET_CLASS, ERR_R_MALLOC_FAILURE);
 345     return p;
 346 }
 347
 348 /*
 349  * Add a new method to the given EX_CLASS_ITEM and return the corresponding
 350  * index (or -1 for error). Handles locking.
 351  */
 352 static int def_add_index(EX_CLASS_ITEM *item, long argl, void *argp,
 353                          CRYPTO_EX_new *new_func, CRYPTO_EX_dup *dup_func,
 354                          CRYPTO_EX_free *free_func)
 355 {
 356     int toret = -1;
 357     CRYPTO_EX_DATA_FUNCS *a =
 358         (CRYPTO_EX_DATA_FUNCS *)OPENSSL_malloc(sizeof(CRYPTO_EX_DATA_FUNCS));
 359     if (!a) {
 360         CRYPTOerr(CRYPTO_F_DEF_ADD_INDEX, ERR_R_MALLOC_FAILURE);
 361         return -1;
 362     }
 363     a->argl = argl;
 364     a->argp = argp;
 365     a->new_func = new_func;
 366     a->dup_func = dup_func;
 367     a->free_func = free_func;
 368     CRYPTO_w_lock(CRYPTO_LOCK_EX_DATA);
 369     while (sk_CRYPTO_EX_DATA_FUNCS_num(item->meth) <= item->meth_num) {
 370         if (!sk_CRYPTO_EX_DATA_FUNCS_push(item->meth, NULL)) {
 371             CRYPTOerr(CRYPTO_F_DEF_ADD_INDEX, ERR_R_MALLOC_FAILURE);
 372             OPENSSL_free(a);
 373             goto err;
 374         }
 375     }
 376     toret = item->meth_num++;
 377     (void)sk_CRYPTO_EX_DATA_FUNCS_set(item->meth, toret, a);
 378  err:
 379     CRYPTO_w_unlock(CRYPTO_LOCK_EX_DATA);
 380     return toret;
 381 }
 382
 383 /**************************************************************/
 384 /* The functions in the default CRYPTO_EX_DATA_IMPL structure */
 385
 386 static int int_new_class(void)
 387 {
 388     int toret;
 389     CRYPTO_w_lock(CRYPTO_LOCK_EX_DATA);
 390     toret = ex_class++;
 391     CRYPTO_w_unlock(CRYPTO_LOCK_EX_DATA);
 392     return toret;
 393 }
 394
 395 static void int_cleanup(void)
 396 {
 397     EX_DATA_CHECK(return;)
 398         lh_EX_CLASS_ITEM_doall(ex_data, def_cleanup_cb);
 399     lh_EX_CLASS_ITEM_free(ex_data);
 400     ex_data = NULL;
 401     impl = NULL;
 402 }
 403
 404 static int int_get_new_index(int class_index, long argl, void *argp,
 405                              CRYPTO_EX_new *new_func, CRYPTO_EX_dup *dup_func,
 406                              CRYPTO_EX_free *free_func)
 407 {
 408     EX_CLASS_ITEM *item = def_get_class(class_index);
 409     if (!item)
 410         return -1;
 411     return def_add_index(item, argl, argp, new_func, dup_func, free_func);
 412 }
 413
 414 /*
 415  * Thread-safe by copying a class's array of "CRYPTO_EX_DATA_FUNCS" entries
 416  * in the lock, then using them outside the lock. NB: Thread-safety only
 417  * applies to the global "ex_data" state (ie. class definitions), not
 418  * thread-safe on 'ad' itself.
 419  */
 420 static int int_new_ex_data(int class_index, void *obj, CRYPTO_EX_DATA *ad)
 421 {
 422     int mx, i;
 423     void *ptr;
 424     CRYPTO_EX_DATA_FUNCS **storage = NULL;
 425     EX_CLASS_ITEM *item = def_get_class(class_index);
 426     if (!item)
 427         /* error is already set */
 428         return 0;
 429     ad->sk = NULL;
 430     CRYPTO_r_lock(CRYPTO_LOCK_EX_DATA);
 431     mx = sk_CRYPTO_EX_DATA_FUNCS_num(item->meth);
 432     if (mx > 0) {
 433         storage = OPENSSL_malloc(mx * sizeof(CRYPTO_EX_DATA_FUNCS *));
 434         if (!storage)
 435             goto skip;
 436         for (i = 0; i < mx; i++)
 437             storage[i] = sk_CRYPTO_EX_DATA_FUNCS_value(item->meth, i);
 438     }
 439  skip:
 440     CRYPTO_r_unlock(CRYPTO_LOCK_EX_DATA);
 441     if ((mx > 0) && !storage) {
 442         CRYPTOerr(CRYPTO_F_INT_NEW_EX_DATA, ERR_R_MALLOC_FAILURE);
 443         return 0;
 444     }
 445     for (i = 0; i < mx; i++) {
 446         if (storage[i] && storage[i]->new_func) {
 447             ptr = CRYPTO_get_ex_data(ad, i);
 448             storage[i]->new_func(obj, ptr, ad, i,
 449                                  storage[i]->argl, storage[i]->argp);
 450         }
 451     }
 452     if (storage)
 453         OPENSSL_free(storage);
 454     return 1;
 455 }
 456
 457 /* Same thread-safety notes as for "int_new_ex_data" */
 458 static int int_dup_ex_data(int class_index, CRYPTO_EX_DATA *to,
 459                            CRYPTO_EX_DATA *from)
 460 {
 461     int mx, j, i;
 462     void *ptr;
 463     CRYPTO_EX_DATA_FUNCS **storage = NULL;
 464     EX_CLASS_ITEM *item;
 465     if (!from->sk)
 466         /* 'to' should be "blank" which *is* just like 'from' */
 467         return 1;
 468     if ((item = def_get_class(class_index)) == NULL)
 469         return 0;
 470     CRYPTO_r_lock(CRYPTO_LOCK_EX_DATA);
 471     mx = sk_CRYPTO_EX_DATA_FUNCS_num(item->meth);
 472     j = sk_void_num(from->sk);
 473     if (j < mx)
 474         mx = j;
 475     if (mx > 0) {
 476         /*
 477          * Make sure the ex_data stack is at least |mx| elements long to avoid
 478          * issues in the for loop that follows; so go get the |mx|'th element
 479          * (if it does not exist CRYPTO_get_ex_data() returns NULL), and assign
 480          * to itself. This is normally a no-op; but ensures the stack is the
 481          * proper size
 482          */
 483         if (!CRYPTO_set_ex_data(to, mx - 1, CRYPTO_get_ex_data(to, mx - 1)))
 484             goto skip;
 485         storage = OPENSSL_malloc(mx * sizeof(CRYPTO_EX_DATA_FUNCS *));
 486         if (!storage)
 487             goto skip;
 488         for (i = 0; i < mx; i++)
 489             storage[i] = sk_CRYPTO_EX_DATA_FUNCS_value(item->meth, i);
 490     }
 491  skip:
 492     CRYPTO_r_unlock(CRYPTO_LOCK_EX_DATA);
 493     if ((mx > 0) && !storage) {
 494         CRYPTOerr(CRYPTO_F_INT_DUP_EX_DATA, ERR_R_MALLOC_FAILURE);
 495         return 0;
 496     }
 497     for (i = 0; i < mx; i++) {
 498         ptr = CRYPTO_get_ex_data(from, i);
 499         if (storage[i] && storage[i]->dup_func)
 500             storage[i]->dup_func(to, from, &ptr, i,
 501                                  storage[i]->argl, storage[i]->argp);
 502         CRYPTO_set_ex_data(to, i, ptr);
 503     }
 504     if (storage)
 505         OPENSSL_free(storage);
 506     return 1;
 507 }
 508
 509 /* Same thread-safety notes as for "int_new_ex_data" */
 510 static void int_free_ex_data(int class_index, void *obj, CRYPTO_EX_DATA *ad)
 511 {
 512     int mx, i;
 513     EX_CLASS_ITEM *item;
 514     void *ptr;
 515     CRYPTO_EX_DATA_FUNCS *f;
 516     CRYPTO_EX_DATA_FUNCS **storage = NULL;
 517     if (ex_data == NULL)
 518         goto err;
 519     if ((item = def_get_class(class_index)) == NULL)
 520         goto err;
 521     CRYPTO_r_lock(CRYPTO_LOCK_EX_DATA);
 522     mx = sk_CRYPTO_EX_DATA_FUNCS_num(item->meth);
 523     if (mx > 0) {
 524         storage = OPENSSL_malloc(mx * sizeof(CRYPTO_EX_DATA_FUNCS *));
 525         if (!storage)
 526             goto skip;
 527         for (i = 0; i < mx; i++)
 528             storage[i] = sk_CRYPTO_EX_DATA_FUNCS_value(item->meth, i);
 529     }
 530  skip:
 531     CRYPTO_r_unlock(CRYPTO_LOCK_EX_DATA);
 532     for (i = 0; i < mx; i++) {
 533         if (storage != NULL)
 534             f = storage[i];
 535         else {
 536             CRYPTO_r_lock(CRYPTO_LOCK_EX_DATA);
 537             f = sk_CRYPTO_EX_DATA_FUNCS_value(item->meth, i);
 538             CRYPTO_r_unlock(CRYPTO_LOCK_EX_DATA);
 539         }
 540         if (f != NULL && f->free_func != NULL) {
 541             ptr = CRYPTO_get_ex_data(ad, i);
 542             f->free_func(obj, ptr, ad, i, f->argl, f->argp);
 543         }
 544     }
 545     OPENSSL_free(storage);
 546  err:
 547     sk_void_free(ad->sk);
 548     ad->sk = NULL;
 549 }
 550
 551 /********************************************************************/
 552 /*
 553  * API functions that defer all "state" operations to the "ex_data"
 554  * implementation we have set.
 555  */
 556
 557 /*
 558  * Obtain an index for a new class (not the same as getting a new index
 559  * within an existing class - this is actually getting a new *class*)
 560  */
 561 int CRYPTO_ex_data_new_class(void)
 562 {
 563     IMPL_CHECK return EX_IMPL(new_class) ();
 564 }
 565
 566 /*
 567  * Release all "ex_data" state to prevent memory leaks. This can't be made
 568  * thread-safe without overhauling a lot of stuff, and shouldn't really be
 569  * called under potential race-conditions anyway (it's for program shutdown
 570  * after all).
 571  */
 572 void CRYPTO_cleanup_all_ex_data(void)
 573 {
 574     IMPL_CHECK EX_IMPL(cleanup) ();
 575 }
 576
 577 /* Inside an existing class, get/register a new index. */
 578 int CRYPTO_get_ex_new_index(int class_index, long argl, void *argp,
 579                             CRYPTO_EX_new *new_func, CRYPTO_EX_dup *dup_func,
 580                             CRYPTO_EX_free *free_func)
 581 {
 582     int ret = -1;
 583
 584     IMPL_CHECK
 585         ret = EX_IMPL(get_new_index) (class_index,
 586                                       argl, argp, new_func, dup_func,
 587                                       free_func);
 588     return ret;
 589 }
 590
 591 /*
 592  * Initialise a new CRYPTO_EX_DATA for use in a particular class - including
 593  * calling new() callbacks for each index in the class used by this variable
 594  */
 595 int CRYPTO_new_ex_data(int class_index, void *obj, CRYPTO_EX_DATA *ad)
 596 {
 597     IMPL_CHECK return EX_IMPL(new_ex_data) (class_index, obj, ad);
 598 }
 599
 600 /*
 601  * Duplicate a CRYPTO_EX_DATA variable - including calling dup() callbacks
 602  * for each index in the class used by this variable
 603  */
 604 int CRYPTO_dup_ex_data(int class_index, CRYPTO_EX_DATA *to,
 605                        CRYPTO_EX_DATA *from)
 606 {
 607     IMPL_CHECK return EX_IMPL(dup_ex_data) (class_index, to, from);
 608 }
 609
 610 /*
 611  * Cleanup a CRYPTO_EX_DATA variable - including calling free() callbacks for
 612  * each index in the class used by this variable
 613  */
 614 void CRYPTO_free_ex_data(int class_index, void *obj, CRYPTO_EX_DATA *ad)
 615 {
 616     IMPL_CHECK EX_IMPL(free_ex_data) (class_index, obj, ad);
 617 }
 618
 619 /*
 620  * For a given CRYPTO_EX_DATA variable, set the value corresponding to a
 621  * particular index in the class used by this variable
 622  */
 623 int CRYPTO_set_ex_data(CRYPTO_EX_DATA *ad, int idx, void *val)
 624 {
 625     int i;
 626
 627     if (ad->sk == NULL) {
 628         if ((ad->sk = sk_void_new_null()) == NULL) {
 629             CRYPTOerr(CRYPTO_F_CRYPTO_SET_EX_DATA, ERR_R_MALLOC_FAILURE);
 630             return (0);
 631         }
 632     }
 633     i = sk_void_num(ad->sk);
 634
 635     while (i <= idx) {
 636         if (!sk_void_push(ad->sk, NULL)) {
 637             CRYPTOerr(CRYPTO_F_CRYPTO_SET_EX_DATA, ERR_R_MALLOC_FAILURE);
 638             return (0);
 639         }
 640         i++;
 641     }
 642     sk_void_set(ad->sk, idx, val);
 643     return (1);
 644 }
 645
 646 /*
 647  * For a given CRYPTO_EX_DATA_ variable, get the value corresponding to a
 648  * particular index in the class used by this variable
 649  */
 650 void *CRYPTO_get_ex_data(const CRYPTO_EX_DATA *ad, int idx)
 651 {
 652     if (ad->sk == NULL)
 653         return (0);
 654     else if (idx >= sk_void_num(ad->sk))
 655         return (0);
 656     else
 657         return (sk_void_value(ad->sk, idx));
 658 }
 659
 660 IMPLEMENT_STACK_OF(CRYPTO_EX_DATA_FUNCS)