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 drbg->reseed_next_counter = tsan_load(&drbg->reseed_prop_counter);
320 if (drbg->reseed_next_counter) {
321 drbg->reseed_next_counter++;
322 if(!drbg->reseed_next_counter)
323 drbg->reseed_next_counter = 1;
326 if (drbg->get_entropy != NULL)
327 entropylen = drbg->get_entropy(drbg, &entropy, min_entropy,
328 min_entropylen, max_entropylen, 0);
329 if (entropylen < min_entropylen
330 || entropylen > max_entropylen) {
331 RANDerr(RAND_F_RAND_DRBG_INSTANTIATE, RAND_R_ERROR_RETRIEVING_ENTROPY);
335 if (drbg->min_noncelen > 0 && drbg->get_nonce != NULL) {
336 noncelen = drbg->get_nonce(drbg, &nonce, drbg->strength / 2,
337 drbg->min_noncelen, drbg->max_noncelen);
338 if (noncelen < drbg->min_noncelen || noncelen > drbg->max_noncelen) {
339 RANDerr(RAND_F_RAND_DRBG_INSTANTIATE, RAND_R_ERROR_RETRIEVING_NONCE);
344 if (!drbg->meth->instantiate(drbg, entropy, entropylen,
345 nonce, noncelen, pers, perslen)) {
346 RANDerr(RAND_F_RAND_DRBG_INSTANTIATE, RAND_R_ERROR_INSTANTIATING_DRBG);
350 drbg->state = DRBG_READY;
351 drbg->reseed_gen_counter = 0;
352 drbg->reseed_time = time(NULL);
353 tsan_store(&drbg->reseed_prop_counter, drbg->reseed_next_counter);
356 if (entropy != NULL && drbg->cleanup_entropy != NULL)
357 drbg->cleanup_entropy(drbg, entropy, entropylen);
358 if (nonce != NULL && drbg->cleanup_nonce != NULL)
359 drbg->cleanup_nonce(drbg, nonce, noncelen);
360 if (drbg->pool != NULL) {
361 if (drbg->state == DRBG_READY) {
362 RANDerr(RAND_F_RAND_DRBG_INSTANTIATE,
363 RAND_R_ERROR_ENTROPY_POOL_WAS_IGNORED);
364 drbg->state = DRBG_ERROR;
366 rand_pool_free(drbg->pool);
369 if (drbg->state == DRBG_READY)
375 * Uninstantiate |drbg|. Must be instantiated before it can be used.
377 * Requires that drbg->lock is already locked for write, if non-null.
379 * Returns 1 on success, 0 on failure.
381 int RAND_DRBG_uninstantiate(RAND_DRBG *drbg)
383 if (drbg->meth == NULL) {
384 RANDerr(RAND_F_RAND_DRBG_UNINSTANTIATE,
385 RAND_R_NO_DRBG_IMPLEMENTATION_SELECTED);
389 /* Clear the entire drbg->ctr struct, then reset some important
390 * members of the drbg->ctr struct (e.g. keysize, df_ks) to their
393 drbg->meth->uninstantiate(drbg);
394 return RAND_DRBG_set(drbg, drbg->type, drbg->flags);
398 * Reseed |drbg|, mixing in the specified data
400 * Requires that drbg->lock is already locked for write, if non-null.
402 * Returns 1 on success, 0 on failure.
404 int RAND_DRBG_reseed(RAND_DRBG *drbg,
405 const unsigned char *adin, size_t adinlen,
406 int prediction_resistance)
408 unsigned char *entropy = NULL;
409 size_t entropylen = 0;
411 if (drbg->state == DRBG_ERROR) {
412 RANDerr(RAND_F_RAND_DRBG_RESEED, RAND_R_IN_ERROR_STATE);
415 if (drbg->state == DRBG_UNINITIALISED) {
416 RANDerr(RAND_F_RAND_DRBG_RESEED, RAND_R_NOT_INSTANTIATED);
422 } else if (adinlen > drbg->max_adinlen) {
423 RANDerr(RAND_F_RAND_DRBG_RESEED, RAND_R_ADDITIONAL_INPUT_TOO_LONG);
427 drbg->state = DRBG_ERROR;
429 drbg->reseed_next_counter = tsan_load(&drbg->reseed_prop_counter);
430 if (drbg->reseed_next_counter) {
431 drbg->reseed_next_counter++;
432 if(!drbg->reseed_next_counter)
433 drbg->reseed_next_counter = 1;
436 if (drbg->get_entropy != NULL)
437 entropylen = drbg->get_entropy(drbg, &entropy, drbg->strength,
438 drbg->min_entropylen,
439 drbg->max_entropylen,
440 prediction_resistance);
441 if (entropylen < drbg->min_entropylen
442 || entropylen > drbg->max_entropylen) {
443 RANDerr(RAND_F_RAND_DRBG_RESEED, RAND_R_ERROR_RETRIEVING_ENTROPY);
447 if (!drbg->meth->reseed(drbg, entropy, entropylen, adin, adinlen))
450 drbg->state = DRBG_READY;
451 drbg->reseed_gen_counter = 0;
452 drbg->reseed_time = time(NULL);
453 tsan_store(&drbg->reseed_prop_counter, drbg->reseed_next_counter);
456 if (entropy != NULL && drbg->cleanup_entropy != NULL)
457 drbg->cleanup_entropy(drbg, entropy, entropylen);
458 if (drbg->state == DRBG_READY)
464 * Restart |drbg|, using the specified entropy or additional input
466 * Tries its best to get the drbg instantiated by all means,
467 * regardless of its current state.
469 * Optionally, a |buffer| of |len| random bytes can be passed,
470 * which is assumed to contain at least |entropy| bits of entropy.
472 * If |entropy| > 0, the buffer content is used as entropy input.
474 * If |entropy| == 0, the buffer content is used as additional input
476 * Returns 1 on success, 0 on failure.
478 * This function is used internally only.
480 int rand_drbg_restart(RAND_DRBG *drbg,
481 const unsigned char *buffer, size_t len, size_t entropy)
484 const unsigned char *adin = NULL;
487 if (drbg->pool != NULL) {
488 RANDerr(RAND_F_RAND_DRBG_RESTART, ERR_R_INTERNAL_ERROR);
489 drbg->state = DRBG_ERROR;
490 rand_pool_free(drbg->pool);
495 if (buffer != NULL) {
497 if (drbg->max_entropylen < len) {
498 RANDerr(RAND_F_RAND_DRBG_RESTART,
499 RAND_R_ENTROPY_INPUT_TOO_LONG);
500 drbg->state = DRBG_ERROR;
504 if (entropy > 8 * len) {
505 RANDerr(RAND_F_RAND_DRBG_RESTART, RAND_R_ENTROPY_OUT_OF_RANGE);
506 drbg->state = DRBG_ERROR;
510 /* will be picked up by the rand_drbg_get_entropy() callback */
511 drbg->pool = rand_pool_attach(buffer, len, entropy);
512 if (drbg->pool == NULL)
515 if (drbg->max_adinlen < len) {
516 RANDerr(RAND_F_RAND_DRBG_RESTART,
517 RAND_R_ADDITIONAL_INPUT_TOO_LONG);
518 drbg->state = DRBG_ERROR;
526 /* repair error state */
527 if (drbg->state == DRBG_ERROR)
528 RAND_DRBG_uninstantiate(drbg);
530 /* repair uninitialized state */
531 if (drbg->state == DRBG_UNINITIALISED) {
532 /* reinstantiate drbg */
533 RAND_DRBG_instantiate(drbg,
534 (const unsigned char *) ossl_pers_string,
535 sizeof(ossl_pers_string) - 1);
536 /* already reseeded. prevent second reseeding below */
537 reseeded = (drbg->state == DRBG_READY);
540 /* refresh current state if entropy or additional input has been provided */
541 if (drbg->state == DRBG_READY) {
544 * mix in additional input without reseeding
546 * Similar to RAND_DRBG_reseed(), but the provided additional
547 * data |adin| is mixed into the current state without pulling
548 * entropy from the trusted entropy source using get_entropy().
549 * This is not a reseeding in the strict sense of NIST SP 800-90A.
551 drbg->meth->reseed(drbg, adin, adinlen, NULL, 0);
552 } else if (reseeded == 0) {
553 /* do a full reseeding if it has not been done yet above */
554 RAND_DRBG_reseed(drbg, NULL, 0, 0);
558 /* check whether a given entropy pool was cleared properly during reseed */
559 if (drbg->pool != NULL) {
560 drbg->state = DRBG_ERROR;
561 RANDerr(RAND_F_RAND_DRBG_RESTART, ERR_R_INTERNAL_ERROR);
562 rand_pool_free(drbg->pool);
567 return drbg->state == DRBG_READY;
571 * Generate |outlen| bytes into the buffer at |out|. Reseed if we need
572 * to or if |prediction_resistance| is set. Additional input can be
573 * sent in |adin| and |adinlen|.
575 * Requires that drbg->lock is already locked for write, if non-null.
577 * Returns 1 on success, 0 on failure.
580 int RAND_DRBG_generate(RAND_DRBG *drbg, unsigned char *out, size_t outlen,
581 int prediction_resistance,
582 const unsigned char *adin, size_t adinlen)
584 int reseed_required = 0;
586 if (drbg->state != DRBG_READY) {
587 /* try to recover from previous errors */
588 rand_drbg_restart(drbg, NULL, 0, 0);
590 if (drbg->state == DRBG_ERROR) {
591 RANDerr(RAND_F_RAND_DRBG_GENERATE, RAND_R_IN_ERROR_STATE);
594 if (drbg->state == DRBG_UNINITIALISED) {
595 RANDerr(RAND_F_RAND_DRBG_GENERATE, RAND_R_NOT_INSTANTIATED);
600 if (outlen > drbg->max_request) {
601 RANDerr(RAND_F_RAND_DRBG_GENERATE, RAND_R_REQUEST_TOO_LARGE_FOR_DRBG);
604 if (adinlen > drbg->max_adinlen) {
605 RANDerr(RAND_F_RAND_DRBG_GENERATE, RAND_R_ADDITIONAL_INPUT_TOO_LONG);
609 if (drbg->fork_count != rand_fork_count) {
610 drbg->fork_count = rand_fork_count;
614 if (drbg->reseed_interval > 0) {
615 if (drbg->reseed_gen_counter >= drbg->reseed_interval)
618 if (drbg->reseed_time_interval > 0) {
619 time_t now = time(NULL);
620 if (now < drbg->reseed_time
621 || now - drbg->reseed_time >= drbg->reseed_time_interval)
624 if (drbg->parent != NULL) {
625 unsigned int reseed_counter = tsan_load(&drbg->reseed_prop_counter);
626 if (reseed_counter > 0
627 && tsan_load(&drbg->parent->reseed_prop_counter)
632 if (reseed_required || prediction_resistance) {
633 if (!RAND_DRBG_reseed(drbg, adin, adinlen, prediction_resistance)) {
634 RANDerr(RAND_F_RAND_DRBG_GENERATE, RAND_R_RESEED_ERROR);
641 if (!drbg->meth->generate(drbg, out, outlen, adin, adinlen)) {
642 drbg->state = DRBG_ERROR;
643 RANDerr(RAND_F_RAND_DRBG_GENERATE, RAND_R_GENERATE_ERROR);
647 drbg->reseed_gen_counter++;
653 * Generates |outlen| random bytes and stores them in |out|. It will
654 * using the given |drbg| to generate the bytes.
656 * Requires that drbg->lock is already locked for write, if non-null.
658 * Returns 1 on success 0 on failure.
660 int RAND_DRBG_bytes(RAND_DRBG *drbg, unsigned char *out, size_t outlen)
662 unsigned char *additional = NULL;
663 size_t additional_len;
667 additional_len = rand_drbg_get_additional_data(&additional, drbg->max_adinlen);
669 for ( ; outlen > 0; outlen -= chunk, out += chunk) {
671 if (chunk > drbg->max_request)
672 chunk = drbg->max_request;
673 ret = RAND_DRBG_generate(drbg, out, chunk, 0, additional, additional_len);
680 if (additional_len != 0)
681 OPENSSL_secure_clear_free(additional, additional_len);
687 * Set the RAND_DRBG callbacks for obtaining entropy and nonce.
689 * Setting the callbacks is allowed only if the drbg has not been
690 * initialized yet. Otherwise, the operation will fail.
692 * Returns 1 on success, 0 on failure.
694 int RAND_DRBG_set_callbacks(RAND_DRBG *drbg,
695 RAND_DRBG_get_entropy_fn get_entropy,
696 RAND_DRBG_cleanup_entropy_fn cleanup_entropy,
697 RAND_DRBG_get_nonce_fn get_nonce,
698 RAND_DRBG_cleanup_nonce_fn cleanup_nonce)
700 if (drbg->state != DRBG_UNINITIALISED
701 || drbg->parent != NULL)
703 drbg->get_entropy = get_entropy;
704 drbg->cleanup_entropy = cleanup_entropy;
705 drbg->get_nonce = get_nonce;
706 drbg->cleanup_nonce = cleanup_nonce;
711 * Set the reseed interval.
713 * The drbg will reseed automatically whenever the number of generate
714 * requests exceeds the given reseed interval. If the reseed interval
715 * is 0, then this feature is disabled.
717 * Returns 1 on success, 0 on failure.
719 int RAND_DRBG_set_reseed_interval(RAND_DRBG *drbg, unsigned int interval)
721 if (interval > MAX_RESEED_INTERVAL)
723 drbg->reseed_interval = interval;
728 * Set the reseed time interval.
730 * The drbg will reseed automatically whenever the time elapsed since
731 * the last reseeding exceeds the given reseed time interval. For safety,
732 * a reseeding will also occur if the clock has been reset to a smaller
735 * Returns 1 on success, 0 on failure.
737 int RAND_DRBG_set_reseed_time_interval(RAND_DRBG *drbg, time_t interval)
739 if (interval > MAX_RESEED_TIME_INTERVAL)
741 drbg->reseed_time_interval = interval;
746 * Set the default values for reseed (time) intervals of new DRBG instances
748 * The default values can be set independently for master DRBG instances
749 * (without a parent) and slave DRBG instances (with parent).
751 * Returns 1 on success, 0 on failure.
754 int RAND_DRBG_set_reseed_defaults(
755 unsigned int _master_reseed_interval,
756 unsigned int _slave_reseed_interval,
757 time_t _master_reseed_time_interval,
758 time_t _slave_reseed_time_interval
761 if (_master_reseed_interval > MAX_RESEED_INTERVAL
762 || _slave_reseed_interval > MAX_RESEED_INTERVAL)
765 if (_master_reseed_time_interval > MAX_RESEED_TIME_INTERVAL
766 || _slave_reseed_time_interval > MAX_RESEED_TIME_INTERVAL)
769 master_reseed_interval = _master_reseed_interval;
770 slave_reseed_interval = _slave_reseed_interval;
772 master_reseed_time_interval = _master_reseed_time_interval;
773 slave_reseed_time_interval = _slave_reseed_time_interval;
779 * Locks the given drbg. Locking a drbg which does not have locking
780 * enabled is considered a successful no-op.
782 * Returns 1 on success, 0 on failure.
784 int rand_drbg_lock(RAND_DRBG *drbg)
786 if (drbg->lock != NULL)
787 return CRYPTO_THREAD_write_lock(drbg->lock);
793 * Unlocks the given drbg. Unlocking a drbg which does not have locking
794 * enabled is considered a successful no-op.
796 * Returns 1 on success, 0 on failure.
798 int rand_drbg_unlock(RAND_DRBG *drbg)
800 if (drbg->lock != NULL)
801 return CRYPTO_THREAD_unlock(drbg->lock);
807 * Enables locking for the given drbg
809 * Locking can only be enabled if the random generator
810 * is in the uninitialized state.
812 * Returns 1 on success, 0 on failure.
814 int rand_drbg_enable_locking(RAND_DRBG *drbg)
816 if (drbg->state != DRBG_UNINITIALISED) {
817 RANDerr(RAND_F_RAND_DRBG_ENABLE_LOCKING,
818 RAND_R_DRBG_ALREADY_INITIALIZED);
822 if (drbg->lock == NULL) {
823 if (drbg->parent != NULL && drbg->parent->lock == NULL) {
824 RANDerr(RAND_F_RAND_DRBG_ENABLE_LOCKING,
825 RAND_R_PARENT_LOCKING_NOT_ENABLED);
829 drbg->lock = CRYPTO_THREAD_lock_new();
830 if (drbg->lock == NULL) {
831 RANDerr(RAND_F_RAND_DRBG_ENABLE_LOCKING,
832 RAND_R_FAILED_TO_CREATE_LOCK);
841 * Get and set the EXDATA
843 int RAND_DRBG_set_ex_data(RAND_DRBG *drbg, int idx, void *arg)
845 return CRYPTO_set_ex_data(&drbg->ex_data, idx, arg);
848 void *RAND_DRBG_get_ex_data(const RAND_DRBG *drbg, int idx)
850 return CRYPTO_get_ex_data(&drbg->ex_data, idx);
855 * The following functions provide a RAND_METHOD that works on the
856 * global DRBG. They lock.
860 * Allocates a new global DRBG on the secure heap (if enabled) and
861 * initializes it with default settings.
863 * Returns a pointer to the new DRBG instance on success, NULL on failure.
865 static RAND_DRBG *drbg_setup(RAND_DRBG *parent)
869 drbg = RAND_DRBG_secure_new(rand_drbg_type, rand_drbg_flags, parent);
873 /* Only the master DRBG needs to have a lock */
874 if (parent == NULL && rand_drbg_enable_locking(drbg) == 0)
877 /* enable seed propagation */
878 tsan_store(&drbg->reseed_prop_counter, 1);
881 * Ignore instantiation error to support just-in-time instantiation.
883 * The state of the drbg will be checked in RAND_DRBG_generate() and
884 * an automatic recovery is attempted.
886 (void)RAND_DRBG_instantiate(drbg,
887 (const unsigned char *) ossl_pers_string,
888 sizeof(ossl_pers_string) - 1);
892 RAND_DRBG_free(drbg);
897 * Initialize the global DRBGs on first use.
898 * Returns 1 on success, 0 on failure.
900 DEFINE_RUN_ONCE_STATIC(do_rand_drbg_init)
903 * ensure that libcrypto is initialized, otherwise the
904 * DRBG locks are not cleaned up properly
906 if (!OPENSSL_init_crypto(0, NULL))
909 if (!CRYPTO_THREAD_init_local(&private_drbg, NULL))
912 if (!CRYPTO_THREAD_init_local(&public_drbg, NULL))
915 master_drbg = drbg_setup(NULL);
916 if (master_drbg == NULL)
922 CRYPTO_THREAD_cleanup_local(&public_drbg);
924 CRYPTO_THREAD_cleanup_local(&private_drbg);
928 /* Clean up the global DRBGs before exit */
929 void rand_drbg_cleanup_int(void)
931 if (master_drbg != NULL) {
932 RAND_DRBG_free(master_drbg);
935 CRYPTO_THREAD_cleanup_local(&private_drbg);
936 CRYPTO_THREAD_cleanup_local(&public_drbg);
940 void drbg_delete_thread_state(void)
944 drbg = CRYPTO_THREAD_get_local(&public_drbg);
945 CRYPTO_THREAD_set_local(&public_drbg, NULL);
946 RAND_DRBG_free(drbg);
948 drbg = CRYPTO_THREAD_get_local(&private_drbg);
949 CRYPTO_THREAD_set_local(&private_drbg, NULL);
950 RAND_DRBG_free(drbg);
953 /* Implements the default OpenSSL RAND_bytes() method */
954 static int drbg_bytes(unsigned char *out, int count)
957 RAND_DRBG *drbg = RAND_DRBG_get0_public();
962 ret = RAND_DRBG_bytes(drbg, out, count);
968 * Calculates the minimum length of a full entropy buffer
969 * which is necessary to seed (i.e. instantiate) the DRBG
972 * NOTE: There is a copy of this function in drbgtest.c.
973 * If you change anything here, you need to update
974 * the copy accordingly.
976 static size_t rand_drbg_seedlen(RAND_DRBG *drbg)
979 * If no os entropy source is available then RAND_seed(buffer, bufsize)
980 * is expected to succeed if and only if the buffer length satisfies
981 * the following requirements, which follow from the calculations
982 * in RAND_DRBG_instantiate().
984 size_t min_entropy = drbg->strength;
985 size_t min_entropylen = drbg->min_entropylen;
988 * Extra entropy for the random nonce in the absence of a
989 * get_nonce callback, see comment in RAND_DRBG_instantiate().
991 if (drbg->min_noncelen > 0 && drbg->get_nonce == NULL) {
992 min_entropy += drbg->strength / 2;
993 min_entropylen += drbg->min_noncelen;
997 * Convert entropy requirement from bits to bytes
998 * (dividing by 8 without rounding upwards, because
999 * all entropy requirements are divisible by 8).
1003 /* Return a value that satisfies both requirements */
1004 return min_entropy > min_entropylen ? min_entropy : min_entropylen;
1007 /* Implements the default OpenSSL RAND_add() method */
1008 static int drbg_add(const void *buf, int num, double randomness)
1011 RAND_DRBG *drbg = RAND_DRBG_get0_master();
1018 if (num < 0 || randomness < 0.0)
1021 seedlen = rand_drbg_seedlen(drbg);
1023 buflen = (size_t)num;
1025 if (buflen < seedlen || randomness < (double) seedlen) {
1026 #if defined(OPENSSL_RAND_SEED_NONE)
1028 * If no os entropy source is available, a reseeding will fail
1029 * inevitably. So we use a trick to mix the buffer contents into
1030 * the DRBG state without forcing a reseeding: we generate a
1031 * dummy random byte, using the buffer content as additional data.
1033 unsigned char dummy[1];
1035 return RAND_DRBG_generate(drbg, dummy, sizeof(dummy), 0, buf, buflen);
1038 * If an os entropy source is avaible then we declare the buffer content
1039 * as additional data by setting randomness to zero and trigger a regular
1047 if (randomness > (double)seedlen) {
1049 * The purpose of this check is to bound |randomness| by a
1050 * relatively small value in order to prevent an integer
1051 * overflow when multiplying by 8 in the rand_drbg_restart()
1052 * call below. Note that randomness is measured in bytes,
1053 * not bits, so this value corresponds to eight times the
1054 * security strength.
1056 randomness = (double)seedlen;
1059 rand_drbg_lock(drbg);
1060 ret = rand_drbg_restart(drbg, buf, buflen, (size_t)(8 * randomness));
1061 rand_drbg_unlock(drbg);
1066 /* Implements the default OpenSSL RAND_seed() method */
1067 static int drbg_seed(const void *buf, int num)
1069 return drbg_add(buf, num, num);
1072 /* Implements the default OpenSSL RAND_status() method */
1073 static int drbg_status(void)
1076 RAND_DRBG *drbg = RAND_DRBG_get0_master();
1081 rand_drbg_lock(drbg);
1082 ret = drbg->state == DRBG_READY ? 1 : 0;
1083 rand_drbg_unlock(drbg);
1088 * Get the master DRBG.
1089 * Returns pointer to the DRBG on success, NULL on failure.
1092 RAND_DRBG *RAND_DRBG_get0_master(void)
1094 if (!RUN_ONCE(&rand_drbg_init, do_rand_drbg_init))
1101 * Get the public DRBG.
1102 * Returns pointer to the DRBG on success, NULL on failure.
1104 RAND_DRBG *RAND_DRBG_get0_public(void)
1108 if (!RUN_ONCE(&rand_drbg_init, do_rand_drbg_init))
1111 drbg = CRYPTO_THREAD_get_local(&public_drbg);
1113 if (!ossl_init_thread_start(OPENSSL_INIT_THREAD_RAND))
1115 drbg = drbg_setup(master_drbg);
1116 CRYPTO_THREAD_set_local(&public_drbg, drbg);
1122 * Get the private DRBG.
1123 * Returns pointer to the DRBG on success, NULL on failure.
1125 RAND_DRBG *RAND_DRBG_get0_private(void)
1129 if (!RUN_ONCE(&rand_drbg_init, do_rand_drbg_init))
1132 drbg = CRYPTO_THREAD_get_local(&private_drbg);
1134 if (!ossl_init_thread_start(OPENSSL_INIT_THREAD_RAND))
1136 drbg = drbg_setup(master_drbg);
1137 CRYPTO_THREAD_set_local(&private_drbg, drbg);
1142 RAND_METHOD rand_meth = {
1151 RAND_METHOD *RAND_OpenSSL(void)