crypto/initthread.c

   1 /*
   2  * Copyright 2019 The OpenSSL Project Authors. All Rights Reserved.
   3  *
   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
   8  */
   9
  10 #include <openssl/crypto.h>
  11 #include <openssl/core_numbers.h>
  12 #include "internal/cryptlib_int.h"
  13 #include "internal/providercommon.h"
  14 #include "internal/thread_once.h"
  15
  16 #ifdef FIPS_MODE
  17 /*
  18  * Thread aware code may want to be told about thread stop events. We register
  19  * to hear about those thread stop events when we see a new thread has started.
  20  * We call the ossl_init_thread_start function to do that. In the FIPS provider
  21  * we have our own copy of ossl_init_thread_start, which cascades notifications
  22  * about threads stopping from libcrypto to all the code in the FIPS provider
  23  * that needs to know about it.
  24  *
  25  * The FIPS provider tells libcrypto about which threads it is interested in
  26  * by calling "c_thread_start" which is a function pointer created during
  27  * provider initialisation (i.e. OSSL_init_provider).
  28  */
  29 extern OSSL_core_thread_start_fn *c_thread_start;
  30 #endif
  31
  32 typedef struct thread_event_handler_st THREAD_EVENT_HANDLER;
  33 struct thread_event_handler_st {
  34     const void *index;
  35     void *arg;
  36     OSSL_thread_stop_handler_fn handfn;
  37     THREAD_EVENT_HANDLER *next;
  38 };
  39
  40 #ifndef FIPS_MODE
  41 DEFINE_SPECIAL_STACK_OF(THREAD_EVENT_HANDLER_PTR, THREAD_EVENT_HANDLER *)
  42
  43 typedef struct global_tevent_register_st GLOBAL_TEVENT_REGISTER;
  44 struct global_tevent_register_st {
  45     STACK_OF(THREAD_EVENT_HANDLER_PTR) *skhands;
  46     CRYPTO_RWLOCK *lock;
  47 };
  48
  49 static GLOBAL_TEVENT_REGISTER *glob_tevent_reg = NULL;
  50
  51 static CRYPTO_ONCE tevent_register_runonce = CRYPTO_ONCE_STATIC_INIT;
  52
  53 DEFINE_RUN_ONCE_STATIC(create_global_tevent_register)
  54 {
  55     glob_tevent_reg = OPENSSL_zalloc(sizeof(*glob_tevent_reg));
  56     if (glob_tevent_reg == NULL)
  57         return 0;
  58
  59     glob_tevent_reg->skhands = sk_THREAD_EVENT_HANDLER_PTR_new_null();
  60     glob_tevent_reg->lock = CRYPTO_THREAD_lock_new();
  61     if (glob_tevent_reg->skhands == NULL || glob_tevent_reg->lock == NULL) {
  62         sk_THREAD_EVENT_HANDLER_PTR_free(glob_tevent_reg->skhands);
  63         CRYPTO_THREAD_lock_free(glob_tevent_reg->lock);
  64         OPENSSL_free(glob_tevent_reg);
  65         glob_tevent_reg = NULL;
  66         return 0;
  67     }
  68
  69     return 1;
  70 }
  71
  72 static GLOBAL_TEVENT_REGISTER *get_global_tevent_register(void)
  73 {
  74     if (!RUN_ONCE(&tevent_register_runonce, create_global_tevent_register))
  75         return NULL;
  76     return glob_tevent_reg;
  77 }
  78 #endif
  79
  80 #ifndef FIPS_MODE
  81 static int  init_thread_push_handlers(THREAD_EVENT_HANDLER **hands);
  82 static void init_thread_remove_handlers(THREAD_EVENT_HANDLER **handsin);
  83 static void init_thread_destructor(void *hands);
  84 static int  init_thread_deregister(void *arg, int all);
  85 #endif
  86 static void init_thread_stop(void *arg, THREAD_EVENT_HANDLER **hands);
  87
  88 static THREAD_EVENT_HANDLER **
  89 init_get_thread_local(CRYPTO_THREAD_LOCAL *local, int alloc, int keep)
  90 {
  91     THREAD_EVENT_HANDLER **hands = CRYPTO_THREAD_get_local(local);
  92
  93     if (alloc) {
  94         if (hands == NULL) {
  95
  96             if ((hands = OPENSSL_zalloc(sizeof(*hands))) == NULL)
  97                 return NULL;
  98
  99             if (!CRYPTO_THREAD_set_local(local, hands)) {
 100                 OPENSSL_free(hands);
 101                 return NULL;
 102             }
 103
 104 #ifndef FIPS_MODE
 105             if (!init_thread_push_handlers(hands)) {
 106                 CRYPTO_THREAD_set_local(local, NULL);
 107                 OPENSSL_free(hands);
 108                 return NULL;
 109             }
 110 #endif
 111         }
 112     } else if (!keep) {
 113         CRYPTO_THREAD_set_local(local, NULL);
 114     }
 115
 116     return hands;
 117 }
 118
 119 #ifndef FIPS_MODE
 120 /*
 121  * Since per-thread-specific-data destructors are not universally
 122  * available, i.e. not on Windows, only below CRYPTO_THREAD_LOCAL key
 123  * is assumed to have destructor associated. And then an effort is made
 124  * to call this single destructor on non-pthread platform[s].
 125  *
 126  * Initial value is "impossible". It is used as guard value to shortcut
 127  * destructor for threads terminating before libcrypto is initialized or
 128  * after it's de-initialized. Access to the key doesn't have to be
 129  * serialized for the said threads, because they didn't use libcrypto
 130  * and it doesn't matter if they pick "impossible" or dereference real
 131  * key value and pull NULL past initialization in the first thread that
 132  * intends to use libcrypto.
 133  */
 134 static union {
 135     long sane;
 136     CRYPTO_THREAD_LOCAL value;
 137 } destructor_key = { -1 };
 138
 139 /*
 140  * The thread event handler list is a thread specific linked list
 141  * of callback functions which are invoked in list order by the
 142  * current thread in case of certain events. (Currently, there is
 143  * only one type of event, the 'thread stop' event.)
 144  *
 145  * We also keep a global reference to that linked list, so that we
 146  * can deregister handlers if necessary before all the threads are
 147  * stopped.
 148  */
 149 static int init_thread_push_handlers(THREAD_EVENT_HANDLER **hands)
 150 {
 151     int ret;
 152     GLOBAL_TEVENT_REGISTER *gtr;
 153
 154     gtr = get_global_tevent_register();
 155     if (gtr == NULL)
 156         return 0;
 157
 158     CRYPTO_THREAD_write_lock(gtr->lock);
 159     ret = (sk_THREAD_EVENT_HANDLER_PTR_push(gtr->skhands, hands) != 0);
 160     CRYPTO_THREAD_unlock(gtr->lock);
 161
 162     return ret;
 163 }
 164
 165 static void init_thread_remove_handlers(THREAD_EVENT_HANDLER **handsin)
 166 {
 167     GLOBAL_TEVENT_REGISTER *gtr;
 168     int i;
 169
 170     gtr = get_global_tevent_register();
 171     if (gtr == NULL)
 172         return;
 173     CRYPTO_THREAD_write_lock(gtr->lock);
 174     for (i = 0; i < sk_THREAD_EVENT_HANDLER_PTR_num(gtr->skhands); i++) {
 175         THREAD_EVENT_HANDLER **hands
 176             = sk_THREAD_EVENT_HANDLER_PTR_value(gtr->skhands, i);
 177
 178         if (hands == handsin) {
 179             hands = sk_THREAD_EVENT_HANDLER_PTR_delete(gtr->skhands, i);
 180             CRYPTO_THREAD_unlock(gtr->lock);
 181             return;
 182         }
 183     }
 184     CRYPTO_THREAD_unlock(gtr->lock);
 185     return;
 186 }
 187
 188 static void init_thread_destructor(void *hands)
 189 {
 190     init_thread_stop(NULL, (THREAD_EVENT_HANDLER **)hands);
 191     init_thread_remove_handlers(hands);
 192     OPENSSL_free(hands);
 193 }
 194
 195 int ossl_init_thread(void)
 196 {
 197     if (!CRYPTO_THREAD_init_local(&destructor_key.value,
 198                                   init_thread_destructor))
 199         return 0;
 200
 201     return 1;
 202 }
 203
 204 void ossl_cleanup_thread(void)
 205 {
 206     init_thread_deregister(NULL, 1);
 207     CRYPTO_THREAD_cleanup_local(&destructor_key.value);
 208     destructor_key.sane = -1;
 209 }
 210
 211 void OPENSSL_thread_stop_ex(OPENSSL_CTX *ctx)
 212 {
 213     ctx = openssl_ctx_get_concrete(ctx);
 214     /*
 215      * TODO(3.0). It would be nice if we could figure out a way to do this on
 216      * all threads that have used the OPENSSL_CTX when the OPENSSL_CTX is freed.
 217      * This is currently not possible due to the use of thread local variables.
 218      */
 219     ossl_ctx_thread_stop(ctx);
 220 }
 221
 222 void OPENSSL_thread_stop(void)
 223 {
 224     if (destructor_key.sane != -1) {
 225         THREAD_EVENT_HANDLER **hands
 226             = init_get_thread_local(&destructor_key.value, 0, 0);
 227         init_thread_stop(NULL, hands);
 228
 229         init_thread_remove_handlers(hands);
 230         OPENSSL_free(hands);
 231     }
 232 }
 233
 234 void ossl_ctx_thread_stop(void *arg)
 235 {
 236     if (destructor_key.sane != -1) {
 237         THREAD_EVENT_HANDLER **hands
 238             = init_get_thread_local(&destructor_key.value, 0, 1);
 239         init_thread_stop(arg, hands);
 240     }
 241 }
 242
 243 #else
 244
 245 static void *thread_event_ossl_ctx_new(OPENSSL_CTX *libctx)
 246 {
 247     THREAD_EVENT_HANDLER **hands = NULL;
 248     CRYPTO_THREAD_LOCAL *tlocal = OPENSSL_zalloc(sizeof(*tlocal));
 249
 250     if (tlocal == NULL)
 251         return NULL;
 252
 253     if (!CRYPTO_THREAD_init_local(tlocal,  NULL)) {
 254         goto err;
 255     }
 256
 257     hands = OPENSSL_zalloc(sizeof(*hands));
 258     if (hands == NULL)
 259         goto err;
 260
 261     if (!CRYPTO_THREAD_set_local(tlocal, hands))
 262         goto err;
 263
 264     return tlocal;
 265  err:
 266     OPENSSL_free(hands);
 267     OPENSSL_free(tlocal);
 268     return NULL;
 269 }
 270
 271 static void thread_event_ossl_ctx_free(void *tlocal)
 272 {
 273     OPENSSL_free(tlocal);
 274 }
 275
 276 static const OPENSSL_CTX_METHOD thread_event_ossl_ctx_method = {
 277     thread_event_ossl_ctx_new,
 278     thread_event_ossl_ctx_free,
 279 };
 280
 281 void ossl_ctx_thread_stop(void *arg)
 282 {
 283     THREAD_EVENT_HANDLER **hands;
 284     OPENSSL_CTX *ctx = arg;
 285     CRYPTO_THREAD_LOCAL *local
 286         = openssl_ctx_get_data(ctx, OPENSSL_CTX_THREAD_EVENT_HANDLER_INDEX,
 287                                &thread_event_ossl_ctx_method);
 288
 289     if (local == NULL)
 290         return;
 291     hands = init_get_thread_local(local, 0, 0);
 292     init_thread_stop(arg, hands);
 293     OPENSSL_free(hands);
 294 }
 295 #endif /* FIPS_MODE */
 296
 297
 298 static void init_thread_stop(void *arg, THREAD_EVENT_HANDLER **hands)
 299 {
 300     THREAD_EVENT_HANDLER *curr, *prev = NULL;
 301
 302     /* Can't do much about this */
 303     if (hands == NULL)
 304         return;
 305
 306     curr = *hands;
 307     while (curr != NULL) {
 308         if (arg != NULL && curr->arg != arg) {
 309             curr = curr->next;
 310             continue;
 311         }
 312         curr->handfn(curr->arg);
 313         prev = curr;
 314         curr = curr->next;
 315         if (prev == *hands)
 316             *hands = curr;
 317         OPENSSL_free(prev);
 318     }
 319 }
 320
 321 int ossl_init_thread_start(const void *index, void *arg,
 322                            OSSL_thread_stop_handler_fn handfn)
 323 {
 324     THREAD_EVENT_HANDLER **hands;
 325     THREAD_EVENT_HANDLER *hand;
 326 #ifdef FIPS_MODE
 327     OPENSSL_CTX *ctx = arg;
 328
 329     /*
 330      * In FIPS mode the list of THREAD_EVENT_HANDLERs is unique per combination
 331      * of OPENSSL_CTX and thread. This is because in FIPS mode each OPENSSL_CTX
 332      * gets informed about thread stop events individually.
 333      */
 334     CRYPTO_THREAD_LOCAL *local
 335         = openssl_ctx_get_data(ctx, OPENSSL_CTX_THREAD_EVENT_HANDLER_INDEX,
 336                                &thread_event_ossl_ctx_method);
 337 #else
 338     /*
 339      * Outside of FIPS mode the list of THREAD_EVENT_HANDLERs is unique per
 340      * thread, but may hold multiple OPENSSL_CTXs. We only get told about
 341      * thread stop events globally, so we have to ensure all affected
 342      * OPENSSL_CTXs are informed.
 343      */
 344     CRYPTO_THREAD_LOCAL *local = &destructor_key.value;
 345 #endif
 346
 347     hands = init_get_thread_local(local, 1, 0);
 348     if (hands == NULL)
 349         return 0;
 350
 351 #ifdef FIPS_MODE
 352     if (*hands == NULL) {
 353         /*
 354          * We've not yet registered any handlers for this thread. We need to get
 355          * libcrypto to tell us about later thread stop events. c_thread_start
 356          * is a callback to libcrypto defined in fipsprov.c
 357          */
 358         if (!c_thread_start(FIPS_get_provider(ctx), ossl_ctx_thread_stop))
 359             return 0;
 360     }
 361 #endif
 362
 363     hand = OPENSSL_malloc(sizeof(*hand));
 364     if (hand == NULL)
 365         return 0;
 366
 367     hand->handfn = handfn;
 368     hand->arg = arg;
 369     hand->index = index;
 370     hand->next = *hands;
 371     *hands = hand;
 372
 373     return 1;
 374 }
 375
 376 #ifndef FIPS_MODE
 377 static int init_thread_deregister(void *index, int all)
 378 {
 379     GLOBAL_TEVENT_REGISTER *gtr;
 380     int i;
 381
 382     gtr = get_global_tevent_register();
 383     if (!all)
 384         CRYPTO_THREAD_write_lock(gtr->lock);
 385     for (i = 0; i < sk_THREAD_EVENT_HANDLER_PTR_num(gtr->skhands); i++) {
 386         THREAD_EVENT_HANDLER **hands
 387             = sk_THREAD_EVENT_HANDLER_PTR_value(gtr->skhands, i);
 388         THREAD_EVENT_HANDLER *curr = *hands, *prev = NULL, *tmp;
 389
 390         if (hands == NULL) {
 391             if (!all)
 392                 CRYPTO_THREAD_unlock(gtr->lock);
 393             return 0;
 394         }
 395         while (curr != NULL) {
 396             if (all || curr->index == index) {
 397                 if (prev != NULL)
 398                     prev->next = curr->next;
 399                 else
 400                     *hands = curr->next;
 401                 tmp = curr;
 402                 curr = curr->next;
 403                 OPENSSL_free(tmp);
 404                 continue;
 405             }
 406             prev = curr;
 407             curr = curr->next;
 408         }
 409         if (all)
 410             OPENSSL_free(hands);
 411     }
 412     if (all) {
 413         CRYPTO_THREAD_lock_free(gtr->lock);
 414         sk_THREAD_EVENT_HANDLER_PTR_free(gtr->skhands);
 415         OPENSSL_free(gtr);
 416     } else {
 417         CRYPTO_THREAD_unlock(gtr->lock);
 418     }
 419     return 1;
 420 }
 421
 422 int ossl_init_thread_deregister(void *index)
 423 {
 424     return init_thread_deregister(index, 0);
 425 }
 426 #endif