2 * Copyright 2011-2018 The OpenSSL Project Authors. All Rights Reserved.
4 * Licensed under the OpenSSL license (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
11 #include <openssl/crypto.h>
12 #include <openssl/err.h>
13 #include <openssl/rand.h>
15 #include "internal/thread_once.h"
16 #include "internal/rand_int.h"
17 #include "internal/cryptlib_int.h"
20 * Support framework for NIST SP 800-90A DRBG
22 * See manual page RAND_DRBG(7) for a general overview.
24 * The OpenSSL model is to have new and free functions, and that new
25 * does all initialization. That is not the NIST model, which has
26 * instantiation and un-instantiate, and re-use within a new/free
27 * lifecycle. (No doubt this comes from the desire to support hardware
28 * DRBG, where allocation of resources on something like an HSM is
29 * a much bigger deal than just re-setting an allocated resource.)
33 * The three shared DRBG instances
35 * There are three shared DRBG instances: <master>, <public>, and <private>.
41 * Not used directly by the application, only for reseeding the two other
42 * DRBGs. It reseeds itself by pulling either randomness from os entropy
43 * sources or by consuming randomness which was added by RAND_add().
45 * The <master> DRBG is a global instance which is accessed concurrently by
46 * all threads. The necessary locking is managed automatically by its child
47 * DRBG instances during reseeding.
49 static RAND_DRBG *master_drbg;
53 * Used by default for generating random bytes using RAND_bytes().
55 * The <public> DRBG is thread-local, i.e., there is one instance per thread.
57 static CRYPTO_THREAD_LOCAL public_drbg;
61 * Used by default for generating private keys using RAND_priv_bytes()
63 * The <private> DRBG is thread-local, i.e., there is one instance per thread.
65 static CRYPTO_THREAD_LOCAL private_drbg;
69 /* NIST SP 800-90A DRBG recommends the use of a personalization string. */
70 static const char ossl_pers_string[] = "OpenSSL NIST SP 800-90A DRBG";
72 static CRYPTO_ONCE rand_drbg_init = CRYPTO_ONCE_STATIC_INIT;
76 static int rand_drbg_type = RAND_DRBG_TYPE;
77 static unsigned int rand_drbg_flags = RAND_DRBG_FLAGS;
79 static unsigned int master_reseed_interval = MASTER_RESEED_INTERVAL;
80 static unsigned int slave_reseed_interval = SLAVE_RESEED_INTERVAL;
82 static time_t master_reseed_time_interval = MASTER_RESEED_TIME_INTERVAL;
83 static time_t slave_reseed_time_interval = SLAVE_RESEED_TIME_INTERVAL;
85 /* A logical OR of all used DRBG flag bits (currently there is only one) */
86 static const unsigned int rand_drbg_used_flags =
87 RAND_DRBG_FLAG_CTR_NO_DF;
89 static RAND_DRBG *drbg_setup(RAND_DRBG *parent);
91 static RAND_DRBG *rand_drbg_new(int secure,
97 * Set/initialize |drbg| to be of type |type|, with optional |flags|.
99 * If |type| and |flags| are zero, use the defaults
101 * Returns 1 on success, 0 on failure.
103 int RAND_DRBG_set(RAND_DRBG *drbg, int type, unsigned int flags)
107 if (type == 0 && flags == 0) {
108 type = rand_drbg_type;
109 flags = rand_drbg_flags;
112 drbg->state = DRBG_UNINITIALISED;
118 RANDerr(RAND_F_RAND_DRBG_SET, RAND_R_UNSUPPORTED_DRBG_TYPE);
121 /* Uninitialized; that's okay. */
123 case NID_aes_128_ctr:
124 case NID_aes_192_ctr:
125 case NID_aes_256_ctr:
126 ret = drbg_ctr_init(drbg);
131 RANDerr(RAND_F_RAND_DRBG_SET, RAND_R_ERROR_INITIALISING_DRBG);
136 * Set/initialize default |type| and |flag| for new drbg instances.
138 * Returns 1 on success, 0 on failure.
140 int RAND_DRBG_set_defaults(int type, unsigned int flags)
146 RANDerr(RAND_F_RAND_DRBG_SET_DEFAULTS, RAND_R_UNSUPPORTED_DRBG_TYPE);
148 case NID_aes_128_ctr:
149 case NID_aes_192_ctr:
150 case NID_aes_256_ctr:
154 if ((flags & ~rand_drbg_used_flags) != 0) {
155 RANDerr(RAND_F_RAND_DRBG_SET_DEFAULTS, RAND_R_UNSUPPORTED_DRBG_FLAGS);
159 rand_drbg_type = type;
160 rand_drbg_flags = flags;
167 * Allocate memory and initialize a new DRBG. The DRBG is allocated on
168 * the secure heap if |secure| is nonzero and the secure heap is enabled.
169 * The |parent|, if not NULL, will be used as random source for reseeding.
171 * Returns a pointer to the new DRBG instance on success, NULL on failure.
173 static RAND_DRBG *rand_drbg_new(int secure,
178 RAND_DRBG *drbg = secure ?
179 OPENSSL_secure_zalloc(sizeof(*drbg)) : OPENSSL_zalloc(sizeof(*drbg));
182 RANDerr(RAND_F_RAND_DRBG_NEW, ERR_R_MALLOC_FAILURE);
186 drbg->secure = secure && CRYPTO_secure_allocated(drbg);
187 drbg->fork_count = rand_fork_count;
188 drbg->parent = parent;
190 if (parent == NULL) {
191 drbg->get_entropy = rand_drbg_get_entropy;
192 drbg->cleanup_entropy = rand_drbg_cleanup_entropy;
193 #ifndef RAND_DRBG_GET_RANDOM_NONCE
194 drbg->get_nonce = rand_drbg_get_nonce;
195 drbg->cleanup_nonce = rand_drbg_cleanup_nonce;
198 drbg->reseed_interval = master_reseed_interval;
199 drbg->reseed_time_interval = master_reseed_time_interval;
201 drbg->get_entropy = rand_drbg_get_entropy;
202 drbg->cleanup_entropy = rand_drbg_cleanup_entropy;
204 * Do not provide nonce callbacks, the child DRBGs will
205 * obtain their nonce using random bits from the parent.
208 drbg->reseed_interval = slave_reseed_interval;
209 drbg->reseed_time_interval = slave_reseed_time_interval;
212 if (RAND_DRBG_set(drbg, type, flags) == 0)
215 if (parent != NULL) {
216 rand_drbg_lock(parent);
217 if (drbg->strength > parent->strength) {
219 * We currently don't support the algorithm from NIST SP 800-90C
220 * 10.1.2 to use a weaker DRBG as source
222 rand_drbg_unlock(parent);
223 RANDerr(RAND_F_RAND_DRBG_NEW, RAND_R_PARENT_STRENGTH_TOO_WEAK);
226 rand_drbg_unlock(parent);
233 OPENSSL_secure_free(drbg);
240 RAND_DRBG *RAND_DRBG_new(int type, unsigned int flags, RAND_DRBG *parent)
242 return rand_drbg_new(0, type, flags, parent);
245 RAND_DRBG *RAND_DRBG_secure_new(int type, unsigned int flags, RAND_DRBG *parent)
247 return rand_drbg_new(1, type, flags, parent);
251 * Uninstantiate |drbg| and free all memory.
253 void RAND_DRBG_free(RAND_DRBG *drbg)
258 if (drbg->meth != NULL)
259 drbg->meth->uninstantiate(drbg);
260 CRYPTO_THREAD_lock_free(drbg->lock);
261 CRYPTO_free_ex_data(CRYPTO_EX_INDEX_DRBG, drbg, &drbg->ex_data);
264 OPENSSL_secure_clear_free(drbg, sizeof(*drbg));
266 OPENSSL_clear_free(drbg, sizeof(*drbg));
270 * Instantiate |drbg|, after it has been initialized. Use |pers| and
271 * |perslen| as prediction-resistance input.
273 * Requires that drbg->lock is already locked for write, if non-null.
275 * Returns 1 on success, 0 on failure.
277 int RAND_DRBG_instantiate(RAND_DRBG *drbg,
278 const unsigned char *pers, size_t perslen)
280 unsigned char *nonce = NULL, *entropy = NULL;
281 size_t noncelen = 0, entropylen = 0;
282 size_t min_entropy = drbg->strength;
283 size_t min_entropylen = drbg->min_entropylen;
284 size_t max_entropylen = drbg->max_entropylen;
286 if (perslen > drbg->max_perslen) {
287 RANDerr(RAND_F_RAND_DRBG_INSTANTIATE,
288 RAND_R_PERSONALISATION_STRING_TOO_LONG);
292 if (drbg->meth == NULL) {
293 RANDerr(RAND_F_RAND_DRBG_INSTANTIATE,
294 RAND_R_NO_DRBG_IMPLEMENTATION_SELECTED);
298 if (drbg->state != DRBG_UNINITIALISED) {
299 RANDerr(RAND_F_RAND_DRBG_INSTANTIATE,
300 drbg->state == DRBG_ERROR ? RAND_R_IN_ERROR_STATE
301 : RAND_R_ALREADY_INSTANTIATED);
305 drbg->state = DRBG_ERROR;
308 * NIST SP800-90Ar1 section 9.1 says you can combine getting the entropy
309 * and nonce in 1 call by increasing the entropy with 50% and increasing
310 * the minimum length to accomadate the length of the nonce.
311 * We do this in case a nonce is require and get_nonce is NULL.
313 if (drbg->min_noncelen > 0 && drbg->get_nonce == NULL) {
314 min_entropy += drbg->strength / 2;
315 min_entropylen += drbg->min_noncelen;
316 max_entropylen += drbg->max_noncelen;
319 if (drbg->get_entropy != NULL)
320 entropylen = drbg->get_entropy(drbg, &entropy, min_entropy,
321 min_entropylen, max_entropylen, 0);
322 if (entropylen < min_entropylen
323 || entropylen > max_entropylen) {
324 RANDerr(RAND_F_RAND_DRBG_INSTANTIATE, RAND_R_ERROR_RETRIEVING_ENTROPY);
328 if (drbg->min_noncelen > 0 && drbg->get_nonce != NULL) {
329 noncelen = drbg->get_nonce(drbg, &nonce, drbg->strength / 2,
330 drbg->min_noncelen, drbg->max_noncelen);
331 if (noncelen < drbg->min_noncelen || noncelen > drbg->max_noncelen) {
332 RANDerr(RAND_F_RAND_DRBG_INSTANTIATE, RAND_R_ERROR_RETRIEVING_NONCE);
337 if (!drbg->meth->instantiate(drbg, entropy, entropylen,
338 nonce, noncelen, pers, perslen)) {
339 RANDerr(RAND_F_RAND_DRBG_INSTANTIATE, RAND_R_ERROR_INSTANTIATING_DRBG);
343 drbg->state = DRBG_READY;
344 drbg->reseed_gen_counter = 0;
345 drbg->reseed_time = time(NULL);
346 if (drbg->reseed_prop_counter > 0) {
347 if (drbg->parent == NULL)
348 drbg->reseed_prop_counter++;
350 drbg->reseed_prop_counter = drbg->parent->reseed_prop_counter;
354 if (entropy != NULL && drbg->cleanup_entropy != NULL)
355 drbg->cleanup_entropy(drbg, entropy, entropylen);
356 if (nonce != NULL && drbg->cleanup_nonce != NULL)
357 drbg->cleanup_nonce(drbg, nonce, noncelen);
358 if (drbg->pool != NULL) {
359 if (drbg->state == DRBG_READY) {
360 RANDerr(RAND_F_RAND_DRBG_INSTANTIATE,
361 RAND_R_ERROR_ENTROPY_POOL_WAS_IGNORED);
362 drbg->state = DRBG_ERROR;
364 rand_pool_free(drbg->pool);
367 if (drbg->state == DRBG_READY)
373 * Uninstantiate |drbg|. Must be instantiated before it can be used.
375 * Requires that drbg->lock is already locked for write, if non-null.
377 * Returns 1 on success, 0 on failure.
379 int RAND_DRBG_uninstantiate(RAND_DRBG *drbg)
381 if (drbg->meth == NULL) {
382 RANDerr(RAND_F_RAND_DRBG_UNINSTANTIATE,
383 RAND_R_NO_DRBG_IMPLEMENTATION_SELECTED);
387 /* Clear the entire drbg->ctr struct, then reset some important
388 * members of the drbg->ctr struct (e.g. keysize, df_ks) to their
391 drbg->meth->uninstantiate(drbg);
392 return RAND_DRBG_set(drbg, drbg->type, drbg->flags);
396 * Reseed |drbg|, mixing in the specified data
398 * Requires that drbg->lock is already locked for write, if non-null.
400 * Returns 1 on success, 0 on failure.
402 int RAND_DRBG_reseed(RAND_DRBG *drbg,
403 const unsigned char *adin, size_t adinlen,
404 int prediction_resistance)
406 unsigned char *entropy = NULL;
407 size_t entropylen = 0;
409 if (drbg->state == DRBG_ERROR) {
410 RANDerr(RAND_F_RAND_DRBG_RESEED, RAND_R_IN_ERROR_STATE);
413 if (drbg->state == DRBG_UNINITIALISED) {
414 RANDerr(RAND_F_RAND_DRBG_RESEED, RAND_R_NOT_INSTANTIATED);
420 } else if (adinlen > drbg->max_adinlen) {
421 RANDerr(RAND_F_RAND_DRBG_RESEED, RAND_R_ADDITIONAL_INPUT_TOO_LONG);
425 drbg->state = DRBG_ERROR;
426 if (drbg->get_entropy != NULL)
427 entropylen = drbg->get_entropy(drbg, &entropy, drbg->strength,
428 drbg->min_entropylen,
429 drbg->max_entropylen,
430 prediction_resistance);
431 if (entropylen < drbg->min_entropylen
432 || entropylen > drbg->max_entropylen) {
433 RANDerr(RAND_F_RAND_DRBG_RESEED, RAND_R_ERROR_RETRIEVING_ENTROPY);
437 if (!drbg->meth->reseed(drbg, entropy, entropylen, adin, adinlen))
440 drbg->state = DRBG_READY;
441 drbg->reseed_gen_counter = 0;
442 drbg->reseed_time = time(NULL);
443 if (drbg->reseed_prop_counter > 0) {
444 if (drbg->parent == NULL)
445 drbg->reseed_prop_counter++;
447 drbg->reseed_prop_counter = drbg->parent->reseed_prop_counter;
451 if (entropy != NULL && drbg->cleanup_entropy != NULL)
452 drbg->cleanup_entropy(drbg, entropy, entropylen);
453 if (drbg->state == DRBG_READY)
459 * Restart |drbg|, using the specified entropy or additional input
461 * Tries its best to get the drbg instantiated by all means,
462 * regardless of its current state.
464 * Optionally, a |buffer| of |len| random bytes can be passed,
465 * which is assumed to contain at least |entropy| bits of entropy.
467 * If |entropy| > 0, the buffer content is used as entropy input.
469 * If |entropy| == 0, the buffer content is used as additional input
471 * Returns 1 on success, 0 on failure.
473 * This function is used internally only.
475 int rand_drbg_restart(RAND_DRBG *drbg,
476 const unsigned char *buffer, size_t len, size_t entropy)
479 const unsigned char *adin = NULL;
482 if (drbg->pool != NULL) {
483 RANDerr(RAND_F_RAND_DRBG_RESTART, ERR_R_INTERNAL_ERROR);
484 drbg->state = DRBG_ERROR;
485 rand_pool_free(drbg->pool);
490 if (buffer != NULL) {
492 if (drbg->max_entropylen < len) {
493 RANDerr(RAND_F_RAND_DRBG_RESTART,
494 RAND_R_ENTROPY_INPUT_TOO_LONG);
495 drbg->state = DRBG_ERROR;
499 if (entropy > 8 * len) {
500 RANDerr(RAND_F_RAND_DRBG_RESTART, RAND_R_ENTROPY_OUT_OF_RANGE);
501 drbg->state = DRBG_ERROR;
505 /* will be picked up by the rand_drbg_get_entropy() callback */
506 drbg->pool = rand_pool_attach(buffer, len, entropy);
507 if (drbg->pool == NULL)
510 if (drbg->max_adinlen < len) {
511 RANDerr(RAND_F_RAND_DRBG_RESTART,
512 RAND_R_ADDITIONAL_INPUT_TOO_LONG);
513 drbg->state = DRBG_ERROR;
521 /* repair error state */
522 if (drbg->state == DRBG_ERROR)
523 RAND_DRBG_uninstantiate(drbg);
525 /* repair uninitialized state */
526 if (drbg->state == DRBG_UNINITIALISED) {
527 /* reinstantiate drbg */
528 RAND_DRBG_instantiate(drbg,
529 (const unsigned char *) ossl_pers_string,
530 sizeof(ossl_pers_string) - 1);
531 /* already reseeded. prevent second reseeding below */
532 reseeded = (drbg->state == DRBG_READY);
535 /* refresh current state if entropy or additional input has been provided */
536 if (drbg->state == DRBG_READY) {
539 * mix in additional input without reseeding
541 * Similar to RAND_DRBG_reseed(), but the provided additional
542 * data |adin| is mixed into the current state without pulling
543 * entropy from the trusted entropy source using get_entropy().
544 * This is not a reseeding in the strict sense of NIST SP 800-90A.
546 drbg->meth->reseed(drbg, adin, adinlen, NULL, 0);
547 } else if (reseeded == 0) {
548 /* do a full reseeding if it has not been done yet above */
549 RAND_DRBG_reseed(drbg, NULL, 0, 0);
553 /* check whether a given entropy pool was cleared properly during reseed */
554 if (drbg->pool != NULL) {
555 drbg->state = DRBG_ERROR;
556 RANDerr(RAND_F_RAND_DRBG_RESTART, ERR_R_INTERNAL_ERROR);
557 rand_pool_free(drbg->pool);
562 return drbg->state == DRBG_READY;
566 * Generate |outlen| bytes into the buffer at |out|. Reseed if we need
567 * to or if |prediction_resistance| is set. Additional input can be
568 * sent in |adin| and |adinlen|.
570 * Requires that drbg->lock is already locked for write, if non-null.
572 * Returns 1 on success, 0 on failure.
575 int RAND_DRBG_generate(RAND_DRBG *drbg, unsigned char *out, size_t outlen,
576 int prediction_resistance,
577 const unsigned char *adin, size_t adinlen)
579 int reseed_required = 0;
581 if (drbg->state != DRBG_READY) {
582 /* try to recover from previous errors */
583 rand_drbg_restart(drbg, NULL, 0, 0);
585 if (drbg->state == DRBG_ERROR) {
586 RANDerr(RAND_F_RAND_DRBG_GENERATE, RAND_R_IN_ERROR_STATE);
589 if (drbg->state == DRBG_UNINITIALISED) {
590 RANDerr(RAND_F_RAND_DRBG_GENERATE, RAND_R_NOT_INSTANTIATED);
595 if (outlen > drbg->max_request) {
596 RANDerr(RAND_F_RAND_DRBG_GENERATE, RAND_R_REQUEST_TOO_LARGE_FOR_DRBG);
599 if (adinlen > drbg->max_adinlen) {
600 RANDerr(RAND_F_RAND_DRBG_GENERATE, RAND_R_ADDITIONAL_INPUT_TOO_LONG);
604 if (drbg->fork_count != rand_fork_count) {
605 drbg->fork_count = rand_fork_count;
609 if (drbg->reseed_interval > 0) {
610 if (drbg->reseed_gen_counter >= drbg->reseed_interval)
613 if (drbg->reseed_time_interval > 0) {
614 time_t now = time(NULL);
615 if (now < drbg->reseed_time
616 || now - drbg->reseed_time >= drbg->reseed_time_interval)
619 if (drbg->reseed_prop_counter > 0 && drbg->parent != NULL) {
620 if (drbg->reseed_prop_counter != drbg->parent->reseed_prop_counter)
624 if (reseed_required || prediction_resistance) {
625 if (!RAND_DRBG_reseed(drbg, adin, adinlen, prediction_resistance)) {
626 RANDerr(RAND_F_RAND_DRBG_GENERATE, RAND_R_RESEED_ERROR);
633 if (!drbg->meth->generate(drbg, out, outlen, adin, adinlen)) {
634 drbg->state = DRBG_ERROR;
635 RANDerr(RAND_F_RAND_DRBG_GENERATE, RAND_R_GENERATE_ERROR);
639 drbg->reseed_gen_counter++;
645 * Generates |outlen| random bytes and stores them in |out|. It will
646 * using the given |drbg| to generate the bytes.
648 * Requires that drbg->lock is already locked for write, if non-null.
650 * Returns 1 on success 0 on failure.
652 int RAND_DRBG_bytes(RAND_DRBG *drbg, unsigned char *out, size_t outlen)
654 unsigned char *additional = NULL;
655 size_t additional_len;
659 additional_len = rand_drbg_get_additional_data(&additional, drbg->max_adinlen);
661 for ( ; outlen > 0; outlen -= chunk, out += chunk) {
663 if (chunk > drbg->max_request)
664 chunk = drbg->max_request;
665 ret = RAND_DRBG_generate(drbg, out, chunk, 0, additional, additional_len);
672 if (additional_len != 0)
673 OPENSSL_secure_clear_free(additional, additional_len);
679 * Set the RAND_DRBG callbacks for obtaining entropy and nonce.
681 * Setting the callbacks is allowed only if the drbg has not been
682 * initialized yet. Otherwise, the operation will fail.
684 * Returns 1 on success, 0 on failure.
686 int RAND_DRBG_set_callbacks(RAND_DRBG *drbg,
687 RAND_DRBG_get_entropy_fn get_entropy,
688 RAND_DRBG_cleanup_entropy_fn cleanup_entropy,
689 RAND_DRBG_get_nonce_fn get_nonce,
690 RAND_DRBG_cleanup_nonce_fn cleanup_nonce)
692 if (drbg->state != DRBG_UNINITIALISED)
694 drbg->get_entropy = get_entropy;
695 drbg->cleanup_entropy = cleanup_entropy;
696 drbg->get_nonce = get_nonce;
697 drbg->cleanup_nonce = cleanup_nonce;
702 * Set the reseed interval.
704 * The drbg will reseed automatically whenever the number of generate
705 * requests exceeds the given reseed interval. If the reseed interval
706 * is 0, then this feature is disabled.
708 * Returns 1 on success, 0 on failure.
710 int RAND_DRBG_set_reseed_interval(RAND_DRBG *drbg, unsigned int interval)
712 if (interval > MAX_RESEED_INTERVAL)
714 drbg->reseed_interval = interval;
719 * Set the reseed time interval.
721 * The drbg will reseed automatically whenever the time elapsed since
722 * the last reseeding exceeds the given reseed time interval. For safety,
723 * a reseeding will also occur if the clock has been reset to a smaller
726 * Returns 1 on success, 0 on failure.
728 int RAND_DRBG_set_reseed_time_interval(RAND_DRBG *drbg, time_t interval)
730 if (interval > MAX_RESEED_TIME_INTERVAL)
732 drbg->reseed_time_interval = interval;
737 * Set the default values for reseed (time) intervals of new DRBG instances
739 * The default values can be set independently for master DRBG instances
740 * (without a parent) and slave DRBG instances (with parent).
742 * Returns 1 on success, 0 on failure.
745 int RAND_DRBG_set_reseed_defaults(
746 unsigned int _master_reseed_interval,
747 unsigned int _slave_reseed_interval,
748 time_t _master_reseed_time_interval,
749 time_t _slave_reseed_time_interval
752 if (_master_reseed_interval > MAX_RESEED_INTERVAL
753 || _slave_reseed_interval > MAX_RESEED_INTERVAL)
756 if (_master_reseed_time_interval > MAX_RESEED_TIME_INTERVAL
757 || _slave_reseed_time_interval > MAX_RESEED_TIME_INTERVAL)
760 master_reseed_interval = _master_reseed_interval;
761 slave_reseed_interval = _slave_reseed_interval;
763 master_reseed_time_interval = _master_reseed_time_interval;
764 slave_reseed_time_interval = _slave_reseed_time_interval;
770 * Locks the given drbg. Locking a drbg which does not have locking
771 * enabled is considered a successful no-op.
773 * Returns 1 on success, 0 on failure.
775 int rand_drbg_lock(RAND_DRBG *drbg)
777 if (drbg->lock != NULL)
778 return CRYPTO_THREAD_write_lock(drbg->lock);
784 * Unlocks the given drbg. Unlocking a drbg which does not have locking
785 * enabled is considered a successful no-op.
787 * Returns 1 on success, 0 on failure.
789 int rand_drbg_unlock(RAND_DRBG *drbg)
791 if (drbg->lock != NULL)
792 return CRYPTO_THREAD_unlock(drbg->lock);
798 * Enables locking for the given drbg
800 * Locking can only be enabled if the random generator
801 * is in the uninitialized state.
803 * Returns 1 on success, 0 on failure.
805 int rand_drbg_enable_locking(RAND_DRBG *drbg)
807 if (drbg->state != DRBG_UNINITIALISED) {
808 RANDerr(RAND_F_RAND_DRBG_ENABLE_LOCKING,
809 RAND_R_DRBG_ALREADY_INITIALIZED);
813 if (drbg->lock == NULL) {
814 if (drbg->parent != NULL && drbg->parent->lock == NULL) {
815 RANDerr(RAND_F_RAND_DRBG_ENABLE_LOCKING,
816 RAND_R_PARENT_LOCKING_NOT_ENABLED);
820 drbg->lock = CRYPTO_THREAD_lock_new();
821 if (drbg->lock == NULL) {
822 RANDerr(RAND_F_RAND_DRBG_ENABLE_LOCKING,
823 RAND_R_FAILED_TO_CREATE_LOCK);
832 * Get and set the EXDATA
834 int RAND_DRBG_set_ex_data(RAND_DRBG *drbg, int idx, void *arg)
836 return CRYPTO_set_ex_data(&drbg->ex_data, idx, arg);
839 void *RAND_DRBG_get_ex_data(const RAND_DRBG *drbg, int idx)
841 return CRYPTO_get_ex_data(&drbg->ex_data, idx);
846 * The following functions provide a RAND_METHOD that works on the
847 * global DRBG. They lock.
851 * Allocates a new global DRBG on the secure heap (if enabled) and
852 * initializes it with default settings.
854 * Returns a pointer to the new DRBG instance on success, NULL on failure.
856 static RAND_DRBG *drbg_setup(RAND_DRBG *parent)
860 drbg = RAND_DRBG_secure_new(rand_drbg_type, rand_drbg_flags, parent);
864 /* Only the master DRBG needs to have a lock */
865 if (parent == NULL && rand_drbg_enable_locking(drbg) == 0)
868 /* enable seed propagation */
869 drbg->reseed_prop_counter = 1;
872 * Ignore instantiation error to support just-in-time instantiation.
874 * The state of the drbg will be checked in RAND_DRBG_generate() and
875 * an automatic recovery is attempted.
877 (void)RAND_DRBG_instantiate(drbg,
878 (const unsigned char *) ossl_pers_string,
879 sizeof(ossl_pers_string) - 1);
883 RAND_DRBG_free(drbg);
888 * Initialize the global DRBGs on first use.
889 * Returns 1 on success, 0 on failure.
891 DEFINE_RUN_ONCE_STATIC(do_rand_drbg_init)
894 * ensure that libcrypto is initialized, otherwise the
895 * DRBG locks are not cleaned up properly
897 if (!OPENSSL_init_crypto(0, NULL))
900 if (!CRYPTO_THREAD_init_local(&private_drbg, NULL))
903 if (!CRYPTO_THREAD_init_local(&public_drbg, NULL))
906 master_drbg = drbg_setup(NULL);
907 if (master_drbg == NULL)
913 CRYPTO_THREAD_cleanup_local(&public_drbg);
915 CRYPTO_THREAD_cleanup_local(&private_drbg);
919 /* Clean up the global DRBGs before exit */
920 void rand_drbg_cleanup_int(void)
922 if (master_drbg != NULL) {
923 RAND_DRBG_free(master_drbg);
926 CRYPTO_THREAD_cleanup_local(&private_drbg);
927 CRYPTO_THREAD_cleanup_local(&public_drbg);
931 void drbg_delete_thread_state(void)
935 drbg = CRYPTO_THREAD_get_local(&public_drbg);
936 CRYPTO_THREAD_set_local(&public_drbg, NULL);
937 RAND_DRBG_free(drbg);
939 drbg = CRYPTO_THREAD_get_local(&private_drbg);
940 CRYPTO_THREAD_set_local(&private_drbg, NULL);
941 RAND_DRBG_free(drbg);
944 /* Implements the default OpenSSL RAND_bytes() method */
945 static int drbg_bytes(unsigned char *out, int count)
948 RAND_DRBG *drbg = RAND_DRBG_get0_public();
953 ret = RAND_DRBG_bytes(drbg, out, count);
958 /* Implements the default OpenSSL RAND_add() method */
959 static int drbg_add(const void *buf, int num, double randomness)
962 RAND_DRBG *drbg = RAND_DRBG_get0_master();
967 if (num < 0 || randomness < 0.0)
970 if (randomness > (double)RAND_DRBG_STRENGTH) {
972 * The purpose of this check is to bound |randomness| by a
973 * relatively small value in order to prevent an integer
974 * overflow when multiplying by 8 in the rand_drbg_restart()
975 * call below. Note that randomness is measured in bytes,
976 * not bits, so this value corresponds to eight times the
979 randomness = (double)RAND_DRBG_STRENGTH;
982 rand_drbg_lock(drbg);
983 ret = rand_drbg_restart(drbg, buf,
984 (size_t)(unsigned int)num,
985 (size_t)(8*randomness));
986 rand_drbg_unlock(drbg);
991 /* Implements the default OpenSSL RAND_seed() method */
992 static int drbg_seed(const void *buf, int num)
994 return drbg_add(buf, num, num);
997 /* Implements the default OpenSSL RAND_status() method */
998 static int drbg_status(void)
1001 RAND_DRBG *drbg = RAND_DRBG_get0_master();
1006 rand_drbg_lock(drbg);
1007 ret = drbg->state == DRBG_READY ? 1 : 0;
1008 rand_drbg_unlock(drbg);
1013 * Get the master DRBG.
1014 * Returns pointer to the DRBG on success, NULL on failure.
1017 RAND_DRBG *RAND_DRBG_get0_master(void)
1019 if (!RUN_ONCE(&rand_drbg_init, do_rand_drbg_init))
1026 * Get the public DRBG.
1027 * Returns pointer to the DRBG on success, NULL on failure.
1029 RAND_DRBG *RAND_DRBG_get0_public(void)
1033 if (!RUN_ONCE(&rand_drbg_init, do_rand_drbg_init))
1036 drbg = CRYPTO_THREAD_get_local(&public_drbg);
1038 if (!ossl_init_thread_start(OPENSSL_INIT_THREAD_RAND))
1040 drbg = drbg_setup(master_drbg);
1041 CRYPTO_THREAD_set_local(&public_drbg, drbg);
1047 * Get the private DRBG.
1048 * Returns pointer to the DRBG on success, NULL on failure.
1050 RAND_DRBG *RAND_DRBG_get0_private(void)
1054 if (!RUN_ONCE(&rand_drbg_init, do_rand_drbg_init))
1057 drbg = CRYPTO_THREAD_get_local(&private_drbg);
1059 if (!ossl_init_thread_start(OPENSSL_INIT_THREAD_RAND))
1061 drbg = drbg_setup(master_drbg);
1062 CRYPTO_THREAD_set_local(&private_drbg, drbg);
1067 RAND_METHOD rand_meth = {
1076 RAND_METHOD *RAND_OpenSSL(void)