crypto/initthread.c

   1 /*
   2  * Copyright 2019-2021 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_dispatch.h>
  12 #include "crypto/cryptlib.h"
  13 #include "prov/providercommon.h"
  14 #include "internal/thread_once.h"
  15
  16 #ifdef FIPS_MODULE
  17 #include "prov/provider_ctx.h"
  18
  19 /*
  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.
  26  *
  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).
  30  */
  31 extern OSSL_FUNC_core_thread_start_fn *c_thread_start;
  32 #endif
  33
  34 typedef struct thread_event_handler_st THREAD_EVENT_HANDLER;
  35 struct thread_event_handler_st {
  36     const void *index;
  37     void *arg;
  38     OSSL_thread_stop_handler_fn handfn;
  39     THREAD_EVENT_HANDLER *next;
  40 };
  41
  42 #ifndef FIPS_MODULE
  43 DEFINE_SPECIAL_STACK_OF(THREAD_EVENT_HANDLER_PTR, THREAD_EVENT_HANDLER *)
  44
  45 typedef struct global_tevent_register_st GLOBAL_TEVENT_REGISTER;
  46 struct global_tevent_register_st {
  47     STACK_OF(THREAD_EVENT_HANDLER_PTR) *skhands;
  48     CRYPTO_RWLOCK *lock;
  49 };
  50
  51 static GLOBAL_TEVENT_REGISTER *glob_tevent_reg = NULL;
  52
  53 static CRYPTO_ONCE tevent_register_runonce = CRYPTO_ONCE_STATIC_INIT;
  54
  55 DEFINE_RUN_ONCE_STATIC(create_global_tevent_register)
  56 {
  57     glob_tevent_reg = OPENSSL_zalloc(sizeof(*glob_tevent_reg));
  58     if (glob_tevent_reg == NULL)
  59         return 0;
  60
  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;
  68         return 0;
  69     }
  70
  71     return 1;
  72 }
  73
  74 static GLOBAL_TEVENT_REGISTER *get_global_tevent_register(void)
  75 {
  76     if (!RUN_ONCE(&tevent_register_runonce, create_global_tevent_register))
  77         return NULL;
  78     return glob_tevent_reg;
  79 }
  80 #endif
  81
  82 #ifndef FIPS_MODULE
  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);
  87 #endif
  88 static void init_thread_stop(void *arg, THREAD_EVENT_HANDLER **hands);
  89
  90 static THREAD_EVENT_HANDLER **
  91 init_get_thread_local(CRYPTO_THREAD_LOCAL *local, int alloc, int keep)
  92 {
  93     THREAD_EVENT_HANDLER **hands = CRYPTO_THREAD_get_local(local);
  94
  95     if (alloc) {
  96         if (hands == NULL) {
  97
  98             if ((hands = OPENSSL_zalloc(sizeof(*hands))) == NULL)
  99                 return NULL;
 100
 101             if (!CRYPTO_THREAD_set_local(local, hands)) {
 102                 OPENSSL_free(hands);
 103                 return NULL;
 104             }
 105
 106 #ifndef FIPS_MODULE
 107             if (!init_thread_push_handlers(hands)) {
 108                 CRYPTO_THREAD_set_local(local, NULL);
 109                 OPENSSL_free(hands);
 110                 return NULL;
 111             }
 112 #endif
 113         }
 114     } else if (!keep) {
 115         CRYPTO_THREAD_set_local(local, NULL);
 116     }
 117
 118     return hands;
 119 }
 120
 121 #ifndef FIPS_MODULE
 122 /*
 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].
 127  *
 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.
 135  */
 136 static union {
 137     long sane;
 138     CRYPTO_THREAD_LOCAL value;
 139 } destructor_key = { -1 };
 140
 141 /*
 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.)
 146  *
 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
 149  * stopped.
 150  */
 151 static int init_thread_push_handlers(THREAD_EVENT_HANDLER **hands)
 152 {
 153     int ret;
 154     GLOBAL_TEVENT_REGISTER *gtr;
 155
 156     gtr = get_global_tevent_register();
 157     if (gtr == NULL)
 158         return 0;
 159
 160     if (!CRYPTO_THREAD_write_lock(gtr->lock))
 161         return 0;
 162     ret = (sk_THREAD_EVENT_HANDLER_PTR_push(gtr->skhands, hands) != 0);
 163     CRYPTO_THREAD_unlock(gtr->lock);
 164
 165     return ret;
 166 }
 167
 168 static void init_thread_remove_handlers(THREAD_EVENT_HANDLER **handsin)
 169 {
 170     GLOBAL_TEVENT_REGISTER *gtr;
 171     int i;
 172
 173     gtr = get_global_tevent_register();
 174     if (gtr == NULL)
 175         return;
 176     if (!CRYPTO_THREAD_write_lock(gtr->lock))
 177         return;
 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);
 181
 182         if (hands == handsin) {
 183             sk_THREAD_EVENT_HANDLER_PTR_delete(gtr->skhands, i);
 184             CRYPTO_THREAD_unlock(gtr->lock);
 185             return;
 186         }
 187     }
 188     CRYPTO_THREAD_unlock(gtr->lock);
 189     return;
 190 }
 191
 192 static void init_thread_destructor(void *hands)
 193 {
 194     init_thread_stop(NULL, (THREAD_EVENT_HANDLER **)hands);
 195     init_thread_remove_handlers(hands);
 196     OPENSSL_free(hands);
 197 }
 198
 199 int ossl_init_thread(void)
 200 {
 201     if (!CRYPTO_THREAD_init_local(&destructor_key.value,
 202                                   init_thread_destructor))
 203         return 0;
 204
 205     return 1;
 206 }
 207
 208 void ossl_cleanup_thread(void)
 209 {
 210     init_thread_deregister(NULL, 1);
 211     CRYPTO_THREAD_cleanup_local(&destructor_key.value);
 212     destructor_key.sane = -1;
 213 }
 214
 215 void OPENSSL_thread_stop_ex(OSSL_LIB_CTX *ctx)
 216 {
 217     ctx = ossl_lib_ctx_get_concrete(ctx);
 218     /*
 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.
 222      */
 223     ossl_ctx_thread_stop(ctx);
 224 }
 225
 226 void OPENSSL_thread_stop(void)
 227 {
 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);
 232
 233         init_thread_remove_handlers(hands);
 234         OPENSSL_free(hands);
 235     }
 236 }
 237
 238 void ossl_ctx_thread_stop(void *arg)
 239 {
 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);
 244     }
 245 }
 246
 247 #else
 248
 249 static void *thread_event_ossl_ctx_new(OSSL_LIB_CTX *libctx)
 250 {
 251     THREAD_EVENT_HANDLER **hands = NULL;
 252     CRYPTO_THREAD_LOCAL *tlocal = OPENSSL_zalloc(sizeof(*tlocal));
 253
 254     if (tlocal == NULL)
 255         return NULL;
 256
 257     if (!CRYPTO_THREAD_init_local(tlocal,  NULL)) {
 258         goto err;
 259     }
 260
 261     hands = OPENSSL_zalloc(sizeof(*hands));
 262     if (hands == NULL)
 263         goto err;
 264
 265     if (!CRYPTO_THREAD_set_local(tlocal, hands))
 266         goto err;
 267
 268     return tlocal;
 269  err:
 270     OPENSSL_free(hands);
 271     OPENSSL_free(tlocal);
 272     return NULL;
 273 }
 274
 275 static void thread_event_ossl_ctx_free(void *tlocal)
 276 {
 277     OPENSSL_free(tlocal);
 278 }
 279
 280 static const OSSL_LIB_CTX_METHOD thread_event_ossl_ctx_method = {
 281     thread_event_ossl_ctx_new,
 282     thread_event_ossl_ctx_free,
 283 };
 284
 285 void ossl_ctx_thread_stop(void *arg)
 286 {
 287     THREAD_EVENT_HANDLER **hands;
 288     OSSL_LIB_CTX *ctx = PROV_LIBCTX_OF(arg);
 289     CRYPTO_THREAD_LOCAL *local
 290         = ossl_lib_ctx_get_data(ctx, OSSL_LIB_CTX_THREAD_EVENT_HANDLER_INDEX,
 291                                 &thread_event_ossl_ctx_method);
 292
 293     if (local == NULL)
 294         return;
 295     hands = init_get_thread_local(local, 0, 0);
 296     init_thread_stop(ctx, hands);
 297     OPENSSL_free(hands);
 298 }
 299 #endif /* FIPS_MODULE */
 300
 301
 302 static void init_thread_stop(void *arg, THREAD_EVENT_HANDLER **hands)
 303 {
 304     THREAD_EVENT_HANDLER *curr, *prev = NULL, *tmp;
 305
 306     /* Can't do much about this */
 307     if (hands == NULL)
 308         return;
 309
 310     curr = *hands;
 311     while (curr != NULL) {
 312         if (arg != NULL && curr->arg != arg) {
 313             prev = curr;
 314             curr = curr->next;
 315             continue;
 316         }
 317         curr->handfn(curr->arg);
 318         if (prev == NULL)
 319             *hands = curr->next;
 320         else
 321             prev->next = curr->next;
 322
 323         tmp = curr;
 324         curr = curr->next;
 325
 326         OPENSSL_free(tmp);
 327     }
 328 }
 329
 330 int ossl_init_thread_start(const void *index, void *arg,
 331                            OSSL_thread_stop_handler_fn handfn)
 332 {
 333     THREAD_EVENT_HANDLER **hands;
 334     THREAD_EVENT_HANDLER *hand;
 335 #ifdef FIPS_MODULE
 336     OSSL_LIB_CTX *ctx = arg;
 337
 338     /*
 339      * In FIPS mode the list of THREAD_EVENT_HANDLERs is unique per combination
 340      * of OSSL_LIB_CTX and thread. This is because in FIPS mode each
 341      * OSSL_LIB_CTX gets informed about thread stop events individually.
 342      */
 343     CRYPTO_THREAD_LOCAL *local
 344         = ossl_lib_ctx_get_data(ctx, OSSL_LIB_CTX_THREAD_EVENT_HANDLER_INDEX,
 345                                 &thread_event_ossl_ctx_method);
 346 #else
 347     /*
 348      * Outside of FIPS mode the list of THREAD_EVENT_HANDLERs is unique per
 349      * thread, but may hold multiple OSSL_LIB_CTXs. We only get told about
 350      * thread stop events globally, so we have to ensure all affected
 351      * OSSL_LIB_CTXs are informed.
 352      */
 353     CRYPTO_THREAD_LOCAL *local = &destructor_key.value;
 354 #endif
 355
 356     hands = init_get_thread_local(local, 1, 0);
 357     if (hands == NULL)
 358         return 0;
 359
 360 #ifdef FIPS_MODULE
 361     if (*hands == NULL) {
 362         /*
 363          * We've not yet registered any handlers for this thread. We need to get
 364          * libcrypto to tell us about later thread stop events. c_thread_start
 365          * is a callback to libcrypto defined in fipsprov.c
 366          */
 367         if (!c_thread_start(FIPS_get_core_handle(ctx), ossl_ctx_thread_stop))
 368             return 0;
 369     }
 370 #endif
 371
 372     hand = OPENSSL_malloc(sizeof(*hand));
 373     if (hand == NULL)
 374         return 0;
 375
 376     hand->handfn = handfn;
 377     hand->arg = arg;
 378     hand->index = index;
 379     hand->next = *hands;
 380     *hands = hand;
 381
 382     return 1;
 383 }
 384
 385 #ifndef FIPS_MODULE
 386 static int init_thread_deregister(void *index, int all)
 387 {
 388     GLOBAL_TEVENT_REGISTER *gtr;
 389     int i;
 390
 391     gtr = get_global_tevent_register();
 392     if (gtr == NULL)
 393         return 0;
 394     if (!all) {
 395         if (!CRYPTO_THREAD_write_lock(gtr->lock))
 396             return 0;
 397     } else {
 398         glob_tevent_reg = NULL;
 399     }
 400     for (i = 0; i < sk_THREAD_EVENT_HANDLER_PTR_num(gtr->skhands); i++) {
 401         THREAD_EVENT_HANDLER **hands
 402             = sk_THREAD_EVENT_HANDLER_PTR_value(gtr->skhands, i);
 403         THREAD_EVENT_HANDLER *curr = NULL, *prev = NULL, *tmp;
 404
 405         if (hands == NULL) {
 406             if (!all)
 407                 CRYPTO_THREAD_unlock(gtr->lock);
 408             return 0;
 409         }
 410         curr = *hands;
 411         while (curr != NULL) {
 412             if (all || curr->index == index) {
 413                 if (prev != NULL)
 414                     prev->next = curr->next;
 415                 else
 416                     *hands = curr->next;
 417                 tmp = curr;
 418                 curr = curr->next;
 419                 OPENSSL_free(tmp);
 420                 continue;
 421             }
 422             prev = curr;
 423             curr = curr->next;
 424         }
 425         if (all)
 426             OPENSSL_free(hands);
 427     }
 428     if (all) {
 429         CRYPTO_THREAD_lock_free(gtr->lock);
 430         sk_THREAD_EVENT_HANDLER_PTR_free(gtr->skhands);
 431         OPENSSL_free(gtr);
 432     } else {
 433         CRYPTO_THREAD_unlock(gtr->lock);
 434     }
 435     return 1;
 436 }
 437
 438 int ossl_init_thread_deregister(void *index)
 439 {
 440     return init_thread_deregister(index, 0);
 441 }
 442 #endif