2 * Copyright 2019-2021 The OpenSSL Project Authors. All Rights Reserved.
4 * Licensed under the Apache License 2.0 (the "License"). You may not use
5 * this file except in compliance with the License. You can obtain a copy
6 * in the file LICENSE in the source distribution or at
7 * https://www.openssl.org/source/license.html
10 #include <openssl/crypto.h>
11 #include <openssl/core_dispatch.h>
12 #include "crypto/cryptlib.h"
13 #include "prov/providercommon.h"
14 #include "internal/thread_once.h"
17 #include "prov/provider_ctx.h"
20 * Thread aware code may want to be told about thread stop events. We register
21 * to hear about those thread stop events when we see a new thread has started.
22 * We call the ossl_init_thread_start function to do that. In the FIPS provider
23 * we have our own copy of ossl_init_thread_start, which cascades notifications
24 * about threads stopping from libcrypto to all the code in the FIPS provider
25 * that needs to know about it.
27 * The FIPS provider tells libcrypto about which threads it is interested in
28 * by calling "c_thread_start" which is a function pointer created during
29 * provider initialisation (i.e. OSSL_init_provider).
31 extern OSSL_FUNC_core_thread_start_fn *c_thread_start;
34 typedef struct thread_event_handler_st THREAD_EVENT_HANDLER;
35 struct thread_event_handler_st {
38 OSSL_thread_stop_handler_fn handfn;
39 THREAD_EVENT_HANDLER *next;
43 DEFINE_SPECIAL_STACK_OF(THREAD_EVENT_HANDLER_PTR, THREAD_EVENT_HANDLER *)
45 typedef struct global_tevent_register_st GLOBAL_TEVENT_REGISTER;
46 struct global_tevent_register_st {
47 STACK_OF(THREAD_EVENT_HANDLER_PTR) *skhands;
51 static GLOBAL_TEVENT_REGISTER *glob_tevent_reg = NULL;
53 static CRYPTO_ONCE tevent_register_runonce = CRYPTO_ONCE_STATIC_INIT;
55 DEFINE_RUN_ONCE_STATIC(create_global_tevent_register)
57 glob_tevent_reg = OPENSSL_zalloc(sizeof(*glob_tevent_reg));
58 if (glob_tevent_reg == NULL)
61 glob_tevent_reg->skhands = sk_THREAD_EVENT_HANDLER_PTR_new_null();
62 glob_tevent_reg->lock = CRYPTO_THREAD_lock_new();
63 if (glob_tevent_reg->skhands == NULL || glob_tevent_reg->lock == NULL) {
64 sk_THREAD_EVENT_HANDLER_PTR_free(glob_tevent_reg->skhands);
65 CRYPTO_THREAD_lock_free(glob_tevent_reg->lock);
66 OPENSSL_free(glob_tevent_reg);
67 glob_tevent_reg = NULL;
74 static GLOBAL_TEVENT_REGISTER *get_global_tevent_register(void)
76 if (!RUN_ONCE(&tevent_register_runonce, create_global_tevent_register))
78 return glob_tevent_reg;
83 static int init_thread_push_handlers(THREAD_EVENT_HANDLER **hands);
84 static void init_thread_remove_handlers(THREAD_EVENT_HANDLER **handsin);
85 static void init_thread_destructor(void *hands);
86 static int init_thread_deregister(void *arg, int all);
88 static void init_thread_stop(void *arg, THREAD_EVENT_HANDLER **hands);
90 static THREAD_EVENT_HANDLER **
91 init_get_thread_local(CRYPTO_THREAD_LOCAL *local, int alloc, int keep)
93 THREAD_EVENT_HANDLER **hands = CRYPTO_THREAD_get_local(local);
98 if ((hands = OPENSSL_zalloc(sizeof(*hands))) == NULL)
101 if (!CRYPTO_THREAD_set_local(local, hands)) {
107 if (!init_thread_push_handlers(hands)) {
108 CRYPTO_THREAD_set_local(local, NULL);
115 CRYPTO_THREAD_set_local(local, NULL);
123 * Since per-thread-specific-data destructors are not universally
124 * available, i.e. not on Windows, only below CRYPTO_THREAD_LOCAL key
125 * is assumed to have destructor associated. And then an effort is made
126 * to call this single destructor on non-pthread platform[s].
128 * Initial value is "impossible". It is used as guard value to shortcut
129 * destructor for threads terminating before libcrypto is initialized or
130 * after it's de-initialized. Access to the key doesn't have to be
131 * serialized for the said threads, because they didn't use libcrypto
132 * and it doesn't matter if they pick "impossible" or dereference real
133 * key value and pull NULL past initialization in the first thread that
134 * intends to use libcrypto.
138 CRYPTO_THREAD_LOCAL value;
139 } destructor_key = { -1 };
142 * The thread event handler list is a thread specific linked list
143 * of callback functions which are invoked in list order by the
144 * current thread in case of certain events. (Currently, there is
145 * only one type of event, the 'thread stop' event.)
147 * We also keep a global reference to that linked list, so that we
148 * can deregister handlers if necessary before all the threads are
151 static int init_thread_push_handlers(THREAD_EVENT_HANDLER **hands)
154 GLOBAL_TEVENT_REGISTER *gtr;
156 gtr = get_global_tevent_register();
160 if (!CRYPTO_THREAD_write_lock(gtr->lock))
162 ret = (sk_THREAD_EVENT_HANDLER_PTR_push(gtr->skhands, hands) != 0);
163 CRYPTO_THREAD_unlock(gtr->lock);
168 static void init_thread_remove_handlers(THREAD_EVENT_HANDLER **handsin)
170 GLOBAL_TEVENT_REGISTER *gtr;
173 gtr = get_global_tevent_register();
176 if (!CRYPTO_THREAD_write_lock(gtr->lock))
178 for (i = 0; i < sk_THREAD_EVENT_HANDLER_PTR_num(gtr->skhands); i++) {
179 THREAD_EVENT_HANDLER **hands
180 = sk_THREAD_EVENT_HANDLER_PTR_value(gtr->skhands, i);
182 if (hands == handsin) {
183 sk_THREAD_EVENT_HANDLER_PTR_delete(gtr->skhands, i);
184 CRYPTO_THREAD_unlock(gtr->lock);
188 CRYPTO_THREAD_unlock(gtr->lock);
192 static void init_thread_destructor(void *hands)
194 init_thread_stop(NULL, (THREAD_EVENT_HANDLER **)hands);
195 init_thread_remove_handlers(hands);
199 int ossl_init_thread(void)
201 if (!CRYPTO_THREAD_init_local(&destructor_key.value,
202 init_thread_destructor))
208 void ossl_cleanup_thread(void)
210 init_thread_deregister(NULL, 1);
211 CRYPTO_THREAD_cleanup_local(&destructor_key.value);
212 destructor_key.sane = -1;
215 void OPENSSL_thread_stop_ex(OSSL_LIB_CTX *ctx)
217 ctx = ossl_lib_ctx_get_concrete(ctx);
219 * It would be nice if we could figure out a way to do this on all threads
220 * that have used the OSSL_LIB_CTX when the context is freed. This is
221 * currently not possible due to the use of thread local variables.
223 ossl_ctx_thread_stop(ctx);
226 void OPENSSL_thread_stop(void)
228 if (destructor_key.sane != -1) {
229 THREAD_EVENT_HANDLER **hands
230 = init_get_thread_local(&destructor_key.value, 0, 0);
231 init_thread_stop(NULL, hands);
233 init_thread_remove_handlers(hands);
238 void ossl_ctx_thread_stop(void *arg)
240 if (destructor_key.sane != -1) {
241 THREAD_EVENT_HANDLER **hands
242 = init_get_thread_local(&destructor_key.value, 0, 1);
243 init_thread_stop(arg, hands);
249 static void *thread_event_ossl_ctx_new(OSSL_LIB_CTX *libctx)
251 THREAD_EVENT_HANDLER **hands = NULL;
252 CRYPTO_THREAD_LOCAL *tlocal = OPENSSL_zalloc(sizeof(*tlocal));
257 if (!CRYPTO_THREAD_init_local(tlocal, NULL)) {
261 hands = OPENSSL_zalloc(sizeof(*hands));
265 if (!CRYPTO_THREAD_set_local(tlocal, hands))
271 OPENSSL_free(tlocal);
275 static void thread_event_ossl_ctx_free(void *tlocal)
277 OPENSSL_free(tlocal);
280 static const OSSL_LIB_CTX_METHOD thread_event_ossl_ctx_method = {
281 OSSL_LIB_CTX_METHOD_DEFAULT_PRIORITY,
282 thread_event_ossl_ctx_new,
283 thread_event_ossl_ctx_free,
286 void ossl_ctx_thread_stop(void *arg)
288 THREAD_EVENT_HANDLER **hands;
289 OSSL_LIB_CTX *ctx = PROV_LIBCTX_OF(arg);
290 CRYPTO_THREAD_LOCAL *local
291 = ossl_lib_ctx_get_data(ctx, OSSL_LIB_CTX_THREAD_EVENT_HANDLER_INDEX,
292 &thread_event_ossl_ctx_method);
296 hands = init_get_thread_local(local, 0, 0);
297 init_thread_stop(ctx, hands);
300 #endif /* FIPS_MODULE */
303 static void init_thread_stop(void *arg, THREAD_EVENT_HANDLER **hands)
305 THREAD_EVENT_HANDLER *curr, *prev = NULL, *tmp;
307 /* Can't do much about this */
312 while (curr != NULL) {
313 if (arg != NULL && curr->arg != arg) {
318 curr->handfn(curr->arg);
322 prev->next = curr->next;
331 int ossl_init_thread_start(const void *index, void *arg,
332 OSSL_thread_stop_handler_fn handfn)
334 THREAD_EVENT_HANDLER **hands;
335 THREAD_EVENT_HANDLER *hand;
337 OSSL_LIB_CTX *ctx = arg;
340 * In FIPS mode the list of THREAD_EVENT_HANDLERs is unique per combination
341 * of OSSL_LIB_CTX and thread. This is because in FIPS mode each
342 * OSSL_LIB_CTX gets informed about thread stop events individually.
344 CRYPTO_THREAD_LOCAL *local
345 = ossl_lib_ctx_get_data(ctx, OSSL_LIB_CTX_THREAD_EVENT_HANDLER_INDEX,
346 &thread_event_ossl_ctx_method);
349 * Outside of FIPS mode the list of THREAD_EVENT_HANDLERs is unique per
350 * thread, but may hold multiple OSSL_LIB_CTXs. We only get told about
351 * thread stop events globally, so we have to ensure all affected
352 * OSSL_LIB_CTXs are informed.
354 CRYPTO_THREAD_LOCAL *local = &destructor_key.value;
357 hands = init_get_thread_local(local, 1, 0);
362 if (*hands == NULL) {
364 * We've not yet registered any handlers for this thread. We need to get
365 * libcrypto to tell us about later thread stop events. c_thread_start
366 * is a callback to libcrypto defined in fipsprov.c
368 if (!c_thread_start(FIPS_get_core_handle(ctx), ossl_ctx_thread_stop))
373 hand = OPENSSL_malloc(sizeof(*hand));
377 hand->handfn = handfn;
387 static int init_thread_deregister(void *index, int all)
389 GLOBAL_TEVENT_REGISTER *gtr;
392 gtr = get_global_tevent_register();
396 if (!CRYPTO_THREAD_write_lock(gtr->lock))
399 glob_tevent_reg = NULL;
401 for (i = 0; i < sk_THREAD_EVENT_HANDLER_PTR_num(gtr->skhands); i++) {
402 THREAD_EVENT_HANDLER **hands
403 = sk_THREAD_EVENT_HANDLER_PTR_value(gtr->skhands, i);
404 THREAD_EVENT_HANDLER *curr = NULL, *prev = NULL, *tmp;
408 CRYPTO_THREAD_unlock(gtr->lock);
412 while (curr != NULL) {
413 if (all || curr->index == index) {
415 prev->next = curr->next;
430 CRYPTO_THREAD_lock_free(gtr->lock);
431 sk_THREAD_EVENT_HANDLER_PTR_free(gtr->skhands);
434 CRYPTO_THREAD_unlock(gtr->lock);
439 int ossl_init_thread_deregister(void *index)
441 return init_thread_deregister(index, 0);