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).
31 /* Copyright (C) 1995-1998 Eric Young (eay@cryptsoft.com)
32 * All rights reserved.
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.
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).
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.
52 * Redistribution and use in source and binary forms, with or without
53 * modification, are permitted provided that the following conditions
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)"
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
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.]
90 #include <openssl/buffer.h>
91 #include <openssl/bio.h>
92 #include <openssl/lhash.h>
95 /* What an "implementation of ex_data functionality" looks like */
96 struct st_CRYPTO_EX_DATA_IMPL
98 /*********************/
99 /* GLOBAL OPERATIONS */
100 /* Return a new class index */
101 int (*cb_new_class)(void);
102 /* Cleanup all state used by the implementation */
103 void (*cb_cleanup)(void);
104 /************************/
105 /* PER-CLASS OPERATIONS */
106 /* Get a new method index within a class */
107 int (*cb_get_new_index)(int class_index, long argl, void *argp,
108 CRYPTO_EX_new *new_func, CRYPTO_EX_dup *dup_func,
109 CRYPTO_EX_free *free_func);
110 /* Initialise a new CRYPTO_EX_DATA of a given class */
111 int (*cb_new_ex_data)(int class_index, void *obj,
113 /* Duplicate a CRYPTO_EX_DATA of a given class onto a copy */
114 int (*cb_dup_ex_data)(int class_index, CRYPTO_EX_DATA *to,
115 CRYPTO_EX_DATA *from);
116 /* Cleanup a CRYPTO_EX_DATA of a given class */
117 void (*cb_free_ex_data)(int class_index, void *obj,
121 /* The implementation we use at run-time */
122 static const CRYPTO_EX_DATA_IMPL *impl = NULL;
124 /* To call "impl" functions, use this macro rather than referring to 'impl' directly, eg.
125 * EX_IMPL(get_new_index)(...); */
126 #define EX_IMPL(a) impl->cb_##a
128 /* Predeclare the "default" ex_data implementation */
129 static int int_new_class(void);
130 static void int_cleanup(void);
131 static int int_get_new_index(int class_index, long argl, void *argp,
132 CRYPTO_EX_new *new_func, CRYPTO_EX_dup *dup_func,
133 CRYPTO_EX_free *free_func);
134 static int int_new_ex_data(int class_index, void *obj,
136 static int int_dup_ex_data(int class_index, CRYPTO_EX_DATA *to,
137 CRYPTO_EX_DATA *from);
138 static void int_free_ex_data(int class_index, void *obj,
140 static CRYPTO_EX_DATA_IMPL impl_default =
150 /* Internal function that checks whether "impl" is set and if not, sets it to
152 static void impl_check(void)
154 CRYPTO_w_lock(CRYPTO_LOCK_EX_DATA);
156 impl = &impl_default;
157 CRYPTO_w_unlock(CRYPTO_LOCK_EX_DATA);
159 /* A macro wrapper for impl_check that first uses a non-locked test before
160 * invoking the function (which checks again inside a lock). */
161 #define IMPL_CHECK if(!impl) impl_check();
163 /* API functions to get/set the "ex_data" implementation */
164 const CRYPTO_EX_DATA_IMPL *CRYPTO_get_ex_data_implementation(void)
169 int CRYPTO_set_ex_data_implementation(const CRYPTO_EX_DATA_IMPL *i)
172 CRYPTO_w_lock(CRYPTO_LOCK_EX_DATA);
178 CRYPTO_w_unlock(CRYPTO_LOCK_EX_DATA);
182 /****************************************************************************/
183 /* Interal (default) implementation of "ex_data" support. API functions are
186 /* The type that represents what each "class" used to implement locally. A STACK
187 * of CRYPTO_EX_DATA_FUNCS plus a index-counter. The 'class_index' is the global
188 * value representing the class that is used to distinguish these items. */
189 typedef struct st_ex_class_item {
191 STACK_OF(CRYPTO_EX_DATA_FUNCS) *meth;
195 /* When assigning new class indexes, this is our counter */
196 static int ex_class = CRYPTO_EX_INDEX_USER;
198 /* The global hash table of EX_CLASS_ITEM items */
199 static LHASH *ex_data = NULL;
201 /* The callbacks required in the "ex_data" hash table */
202 static unsigned long ex_hash_cb(const void *a_void)
204 return ((const EX_CLASS_ITEM *)a_void)->class_index;
206 static int ex_cmp_cb(const void *a_void, const void *b_void)
208 return (((const EX_CLASS_ITEM *)a_void)->class_index -
209 ((const EX_CLASS_ITEM *)b_void)->class_index);
212 /* Internal functions used by the "impl_default" implementation to access the
215 static int ex_data_check(void)
218 CRYPTO_w_lock(CRYPTO_LOCK_EX_DATA);
219 if(!ex_data && ((ex_data = lh_new(ex_hash_cb, ex_cmp_cb)) == NULL))
221 CRYPTO_w_unlock(CRYPTO_LOCK_EX_DATA);
224 /* This macros helps reduce the locking from repeated checks because the
225 * ex_data_check() function checks ex_data again inside a lock. */
226 #define EX_DATA_CHECK(iffail) if(!ex_data && !ex_data_check()) {iffail}
228 /* This "inner" callback is used by the callback function that follows it */
229 static void def_cleanup_util_cb(void *a_void)
231 CRYPTO_EX_DATA_FUNCS *v = (CRYPTO_EX_DATA_FUNCS *)a_void;
235 /* This callback is used in lh_doall to destroy all EX_CLASS_ITEM values from
236 * "ex_data" prior to the ex_data hash table being itself destroyed. Doesn't do
238 static void def_cleanup_cb(const void *a_void)
240 EX_CLASS_ITEM *item = (EX_CLASS_ITEM *)a_void;
241 sk_CRYPTO_EX_DATA_FUNCS_pop_free(item->meth, def_cleanup_util_cb);
245 /* Return the EX_CLASS_ITEM from the "ex_data" hash table that corresponds to a
246 * given class. Handles locking. */
247 static EX_CLASS_ITEM *def_get_class(int class_index)
249 EX_CLASS_ITEM d, *p, *gen;
250 EX_DATA_CHECK(return NULL;)
251 d.class_index = class_index;
252 CRYPTO_w_lock(CRYPTO_LOCK_EX_DATA);
253 p = lh_retrieve(ex_data, &d);
256 gen = OPENSSL_malloc(sizeof(EX_CLASS_ITEM));
259 gen->class_index = class_index;
261 gen->meth = sk_CRYPTO_EX_DATA_FUNCS_new_null();
266 /* Because we're inside the ex_data lock, the
267 * return value from the insert will be NULL */
268 lh_insert(ex_data, gen);
273 CRYPTO_w_unlock(CRYPTO_LOCK_EX_DATA);
275 CRYPTOerr(CRYPTO_F_DEF_GET_CLASS,ERR_R_MALLOC_FAILURE);
279 /* Add a new method to the given EX_CLASS_ITEM and return the corresponding
280 * index (or -1 for error). Handles locking. */
281 static int def_add_index(EX_CLASS_ITEM *item, long argl, void *argp,
282 CRYPTO_EX_new *new_func, CRYPTO_EX_dup *dup_func,
283 CRYPTO_EX_free *free_func)
286 CRYPTO_EX_DATA_FUNCS *a = (CRYPTO_EX_DATA_FUNCS *)OPENSSL_malloc(
287 sizeof(CRYPTO_EX_DATA_FUNCS));
290 CRYPTOerr(CRYPTO_F_DEF_ADD_INDEX,ERR_R_MALLOC_FAILURE);
295 a->new_func=new_func;
296 a->dup_func=dup_func;
297 a->free_func=free_func;
298 CRYPTO_w_lock(CRYPTO_LOCK_EX_DATA);
299 while (sk_CRYPTO_EX_DATA_FUNCS_num(item->meth) <= item->meth_num)
301 if (!sk_CRYPTO_EX_DATA_FUNCS_push(item->meth, NULL))
303 CRYPTOerr(CRYPTO_F_DEF_ADD_INDEX,ERR_R_MALLOC_FAILURE);
308 toret = item->meth_num++;
309 sk_CRYPTO_EX_DATA_FUNCS_set(item->meth, toret, a);
311 CRYPTO_w_unlock(CRYPTO_LOCK_EX_DATA);
315 /**************************************************************/
316 /* The functions in the default CRYPTO_EX_DATA_IMPL structure */
318 static int int_new_class(void)
321 CRYPTO_w_lock(CRYPTO_LOCK_EX_DATA);
323 CRYPTO_w_unlock(CRYPTO_LOCK_EX_DATA);
327 static void int_cleanup(void)
329 EX_DATA_CHECK(return;)
330 lh_doall(ex_data, def_cleanup_cb);
336 static int int_get_new_index(int class_index, long argl, void *argp,
337 CRYPTO_EX_new *new_func, CRYPTO_EX_dup *dup_func,
338 CRYPTO_EX_free *free_func)
340 EX_CLASS_ITEM *item = def_get_class(class_index);
343 return def_add_index(item, argl, argp, new_func, dup_func, free_func);
346 /* Thread-safe by copying a class's array of "CRYPTO_EX_DATA_FUNCS" entries in
347 * the lock, then using them outside the lock. NB: Thread-safety only applies to
348 * the global "ex_data" state (ie. class definitions), not thread-safe on 'ad'
350 static int int_new_ex_data(int class_index, void *obj,
355 CRYPTO_EX_DATA_FUNCS **storage = NULL;
356 EX_CLASS_ITEM *item = def_get_class(class_index);
358 /* error is already set */
361 CRYPTO_r_lock(CRYPTO_LOCK_EX_DATA);
362 max = sk_CRYPTO_EX_DATA_FUNCS_num(item->meth);
365 storage = OPENSSL_malloc(max * sizeof(CRYPTO_EX_DATA_FUNCS*));
368 for(i = 0; i < max; i++)
369 storage[i] = sk_CRYPTO_EX_DATA_FUNCS_value(item->meth,i);
372 CRYPTO_r_unlock(CRYPTO_LOCK_EX_DATA);
373 if((max > 0) && !storage)
375 CRYPTOerr(CRYPTO_F_INT_NEW_EX_DATA,ERR_R_MALLOC_FAILURE);
378 for(i = 0; i < max; i++)
380 if(storage[i] && storage[i]->new_func)
382 ptr = CRYPTO_get_ex_data(ad, i);
383 storage[i]->new_func(obj,ptr,ad,i,
384 storage[i]->argl,storage[i]->argp);
388 OPENSSL_free(storage);
392 /* Same thread-safety notes as for "int_new_ex_data" */
393 static int int_dup_ex_data(int class_index, CRYPTO_EX_DATA *to,
394 CRYPTO_EX_DATA *from)
398 CRYPTO_EX_DATA_FUNCS **storage = NULL;
401 /* 'to' should be "blank" which *is* just like 'from' */
403 if((item = def_get_class(class_index)) == NULL)
405 CRYPTO_r_lock(CRYPTO_LOCK_EX_DATA);
406 max = sk_CRYPTO_EX_DATA_FUNCS_num(item->meth);
407 j = sk_num(from->sk);
412 storage = OPENSSL_malloc(max * sizeof(CRYPTO_EX_DATA_FUNCS*));
415 for(i = 0; i < max; i++)
416 storage[i] = sk_CRYPTO_EX_DATA_FUNCS_value(item->meth,i);
419 CRYPTO_r_unlock(CRYPTO_LOCK_EX_DATA);
420 if((max > 0) && !storage)
422 CRYPTOerr(CRYPTO_F_INT_DUP_EX_DATA,ERR_R_MALLOC_FAILURE);
425 for(i = 0; i < max; i++)
427 ptr = CRYPTO_get_ex_data(from, i);
428 if(storage[i] && storage[i]->dup_func)
429 storage[i]->dup_func(to,from,&ptr,i,
430 storage[i]->argl,storage[i]->argp);
431 CRYPTO_set_ex_data(to,i,ptr);
434 OPENSSL_free(storage);
438 /* Same thread-safety notes as for "int_new_ex_data" */
439 static void int_free_ex_data(int class_index, void *obj,
445 CRYPTO_EX_DATA_FUNCS **storage = NULL;
446 if((item = def_get_class(class_index)) == NULL)
448 CRYPTO_r_lock(CRYPTO_LOCK_EX_DATA);
449 max = sk_CRYPTO_EX_DATA_FUNCS_num(item->meth);
452 storage = OPENSSL_malloc(max * sizeof(CRYPTO_EX_DATA_FUNCS*));
455 for(i = 0; i < max; i++)
456 storage[i] = sk_CRYPTO_EX_DATA_FUNCS_value(item->meth,i);
459 CRYPTO_r_unlock(CRYPTO_LOCK_EX_DATA);
460 if((max > 0) && !storage)
462 CRYPTOerr(CRYPTO_F_INT_FREE_EX_DATA,ERR_R_MALLOC_FAILURE);
465 for(i = 0; i < max; i++)
467 if(storage[i] && storage[i]->free_func)
469 ptr = CRYPTO_get_ex_data(ad,i);
470 storage[i]->free_func(obj,ptr,ad,i,
471 storage[i]->argl,storage[i]->argp);
475 OPENSSL_free(storage);
483 /********************************************************************/
484 /* API functions that defer all "state" operations to the "ex_data"
485 * implementation we have set. */
487 /* Obtain an index for a new class (not the same as getting a new index within
488 * an existing class - this is actually getting a new *class*) */
489 int CRYPTO_ex_data_new_class(void)
492 return EX_IMPL(new_class)();
495 /* Release all "ex_data" state to prevent memory leaks. This can't be made
496 * thread-safe without overhauling a lot of stuff, and shouldn't really be
497 * called under potential race-conditions anyway (it's for program shutdown
499 void CRYPTO_cleanup_all_ex_data(void)
502 return EX_IMPL(cleanup)();
505 /* Inside an existing class, get/register a new index. */
506 int CRYPTO_get_ex_new_index(int class_index, long argl, void *argp,
507 CRYPTO_EX_new *new_func, CRYPTO_EX_dup *dup_func,
508 CRYPTO_EX_free *free_func)
513 ret = EX_IMPL(get_new_index)(class_index,
514 argl, argp, new_func, dup_func, free_func);
518 /* Initialise a new CRYPTO_EX_DATA for use in a particular class - including
519 * calling new() callbacks for each index in the class used by this variable */
520 int CRYPTO_new_ex_data(int class_index, void *obj, CRYPTO_EX_DATA *ad)
523 return EX_IMPL(new_ex_data)(class_index, obj, ad);
526 /* Duplicate a CRYPTO_EX_DATA variable - including calling dup() callbacks for
527 * each index in the class used by this variable */
528 int CRYPTO_dup_ex_data(int class_index, CRYPTO_EX_DATA *to,
529 CRYPTO_EX_DATA *from)
532 return EX_IMPL(dup_ex_data)(class_index, to, from);
535 /* Cleanup a CRYPTO_EX_DATA variable - including calling free() callbacks for
536 * each index in the class used by this variable */
537 void CRYPTO_free_ex_data(int class_index, void *obj, CRYPTO_EX_DATA *ad)
540 return EX_IMPL(free_ex_data)(class_index, obj, ad);
543 /* For a given CRYPTO_EX_DATA variable, set the value corresponding to a
544 * particular index in the class used by this variable */
545 int CRYPTO_set_ex_data(CRYPTO_EX_DATA *ad, int idx, void *val)
551 if ((ad->sk=sk_new_null()) == NULL)
553 CRYPTOerr(CRYPTO_F_CRYPTO_SET_EX_DATA,ERR_R_MALLOC_FAILURE);
561 if (!sk_push(ad->sk,NULL))
563 CRYPTOerr(CRYPTO_F_CRYPTO_SET_EX_DATA,ERR_R_MALLOC_FAILURE);
568 sk_set(ad->sk,idx,val);
572 /* For a given CRYPTO_EX_DATA_ variable, get the value corresponding to a
573 * particular index in the class used by this variable */
574 void *CRYPTO_get_ex_data(const CRYPTO_EX_DATA *ad, int idx)
578 else if (idx >= sk_num(ad->sk))
581 return(sk_value(ad->sk,idx));
584 IMPLEMENT_STACK_OF(CRYPTO_EX_DATA_FUNCS)