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->state == DRBG_READY)
366 * Uninstantiate |drbg|. Must be instantiated before it can be used.
368 * Requires that drbg->lock is already locked for write, if non-null.
370 * Returns 1 on success, 0 on failure.
372 int RAND_DRBG_uninstantiate(RAND_DRBG *drbg)
374 if (drbg->meth == NULL) {
375 RANDerr(RAND_F_RAND_DRBG_UNINSTANTIATE,
376 RAND_R_NO_DRBG_IMPLEMENTATION_SELECTED);
380 /* Clear the entire drbg->ctr struct, then reset some important
381 * members of the drbg->ctr struct (e.g. keysize, df_ks) to their
384 drbg->meth->uninstantiate(drbg);
385 return RAND_DRBG_set(drbg, drbg->type, drbg->flags);
389 * Reseed |drbg|, mixing in the specified data
391 * Requires that drbg->lock is already locked for write, if non-null.
393 * Returns 1 on success, 0 on failure.
395 int RAND_DRBG_reseed(RAND_DRBG *drbg,
396 const unsigned char *adin, size_t adinlen,
397 int prediction_resistance)
399 unsigned char *entropy = NULL;
400 size_t entropylen = 0;
402 if (drbg->state == DRBG_ERROR) {
403 RANDerr(RAND_F_RAND_DRBG_RESEED, RAND_R_IN_ERROR_STATE);
406 if (drbg->state == DRBG_UNINITIALISED) {
407 RANDerr(RAND_F_RAND_DRBG_RESEED, RAND_R_NOT_INSTANTIATED);
413 } else if (adinlen > drbg->max_adinlen) {
414 RANDerr(RAND_F_RAND_DRBG_RESEED, RAND_R_ADDITIONAL_INPUT_TOO_LONG);
418 drbg->state = DRBG_ERROR;
420 drbg->reseed_next_counter = tsan_load(&drbg->reseed_prop_counter);
421 if (drbg->reseed_next_counter) {
422 drbg->reseed_next_counter++;
423 if(!drbg->reseed_next_counter)
424 drbg->reseed_next_counter = 1;
427 if (drbg->get_entropy != NULL)
428 entropylen = drbg->get_entropy(drbg, &entropy, drbg->strength,
429 drbg->min_entropylen,
430 drbg->max_entropylen,
431 prediction_resistance);
432 if (entropylen < drbg->min_entropylen
433 || entropylen > drbg->max_entropylen) {
434 RANDerr(RAND_F_RAND_DRBG_RESEED, RAND_R_ERROR_RETRIEVING_ENTROPY);
438 if (!drbg->meth->reseed(drbg, entropy, entropylen, adin, adinlen))
441 drbg->state = DRBG_READY;
442 drbg->reseed_gen_counter = 0;
443 drbg->reseed_time = time(NULL);
444 tsan_store(&drbg->reseed_prop_counter, drbg->reseed_next_counter);
447 if (entropy != NULL && drbg->cleanup_entropy != NULL)
448 drbg->cleanup_entropy(drbg, entropy, entropylen);
449 if (drbg->state == DRBG_READY)
455 * Restart |drbg|, using the specified entropy or additional input
457 * Tries its best to get the drbg instantiated by all means,
458 * regardless of its current state.
460 * Optionally, a |buffer| of |len| random bytes can be passed,
461 * which is assumed to contain at least |entropy| bits of entropy.
463 * If |entropy| > 0, the buffer content is used as entropy input.
465 * If |entropy| == 0, the buffer content is used as additional input
467 * Returns 1 on success, 0 on failure.
469 * This function is used internally only.
471 int rand_drbg_restart(RAND_DRBG *drbg,
472 const unsigned char *buffer, size_t len, size_t entropy)
475 const unsigned char *adin = NULL;
478 if (drbg->pool != NULL) {
479 RANDerr(RAND_F_RAND_DRBG_RESTART, ERR_R_INTERNAL_ERROR);
480 drbg->state = DRBG_ERROR;
481 rand_pool_free(drbg->pool);
486 if (buffer != NULL) {
488 if (drbg->max_entropylen < len) {
489 RANDerr(RAND_F_RAND_DRBG_RESTART,
490 RAND_R_ENTROPY_INPUT_TOO_LONG);
491 drbg->state = DRBG_ERROR;
495 if (entropy > 8 * len) {
496 RANDerr(RAND_F_RAND_DRBG_RESTART, RAND_R_ENTROPY_OUT_OF_RANGE);
497 drbg->state = DRBG_ERROR;
501 /* will be picked up by the rand_drbg_get_entropy() callback */
502 drbg->pool = rand_pool_attach(buffer, len, entropy);
503 if (drbg->pool == NULL)
506 if (drbg->max_adinlen < len) {
507 RANDerr(RAND_F_RAND_DRBG_RESTART,
508 RAND_R_ADDITIONAL_INPUT_TOO_LONG);
509 drbg->state = DRBG_ERROR;
517 /* repair error state */
518 if (drbg->state == DRBG_ERROR)
519 RAND_DRBG_uninstantiate(drbg);
521 /* repair uninitialized state */
522 if (drbg->state == DRBG_UNINITIALISED) {
523 /* reinstantiate drbg */
524 RAND_DRBG_instantiate(drbg,
525 (const unsigned char *) ossl_pers_string,
526 sizeof(ossl_pers_string) - 1);
527 /* already reseeded. prevent second reseeding below */
528 reseeded = (drbg->state == DRBG_READY);
531 /* refresh current state if entropy or additional input has been provided */
532 if (drbg->state == DRBG_READY) {
535 * mix in additional input without reseeding
537 * Similar to RAND_DRBG_reseed(), but the provided additional
538 * data |adin| is mixed into the current state without pulling
539 * entropy from the trusted entropy source using get_entropy().
540 * This is not a reseeding in the strict sense of NIST SP 800-90A.
542 drbg->meth->reseed(drbg, adin, adinlen, NULL, 0);
543 } else if (reseeded == 0) {
544 /* do a full reseeding if it has not been done yet above */
545 RAND_DRBG_reseed(drbg, NULL, 0, 0);
549 rand_pool_free(drbg->pool);
552 return drbg->state == DRBG_READY;
556 * Generate |outlen| bytes into the buffer at |out|. Reseed if we need
557 * to or if |prediction_resistance| is set. Additional input can be
558 * sent in |adin| and |adinlen|.
560 * Requires that drbg->lock is already locked for write, if non-null.
562 * Returns 1 on success, 0 on failure.
565 int RAND_DRBG_generate(RAND_DRBG *drbg, unsigned char *out, size_t outlen,
566 int prediction_resistance,
567 const unsigned char *adin, size_t adinlen)
569 int reseed_required = 0;
571 if (drbg->state != DRBG_READY) {
572 /* try to recover from previous errors */
573 rand_drbg_restart(drbg, NULL, 0, 0);
575 if (drbg->state == DRBG_ERROR) {
576 RANDerr(RAND_F_RAND_DRBG_GENERATE, RAND_R_IN_ERROR_STATE);
579 if (drbg->state == DRBG_UNINITIALISED) {
580 RANDerr(RAND_F_RAND_DRBG_GENERATE, RAND_R_NOT_INSTANTIATED);
585 if (outlen > drbg->max_request) {
586 RANDerr(RAND_F_RAND_DRBG_GENERATE, RAND_R_REQUEST_TOO_LARGE_FOR_DRBG);
589 if (adinlen > drbg->max_adinlen) {
590 RANDerr(RAND_F_RAND_DRBG_GENERATE, RAND_R_ADDITIONAL_INPUT_TOO_LONG);
594 if (drbg->fork_count != rand_fork_count) {
595 drbg->fork_count = rand_fork_count;
599 if (drbg->reseed_interval > 0) {
600 if (drbg->reseed_gen_counter >= drbg->reseed_interval)
603 if (drbg->reseed_time_interval > 0) {
604 time_t now = time(NULL);
605 if (now < drbg->reseed_time
606 || now - drbg->reseed_time >= drbg->reseed_time_interval)
609 if (drbg->parent != NULL) {
610 unsigned int reseed_counter = tsan_load(&drbg->reseed_prop_counter);
611 if (reseed_counter > 0
612 && tsan_load(&drbg->parent->reseed_prop_counter)
617 if (reseed_required || prediction_resistance) {
618 if (!RAND_DRBG_reseed(drbg, adin, adinlen, prediction_resistance)) {
619 RANDerr(RAND_F_RAND_DRBG_GENERATE, RAND_R_RESEED_ERROR);
626 if (!drbg->meth->generate(drbg, out, outlen, adin, adinlen)) {
627 drbg->state = DRBG_ERROR;
628 RANDerr(RAND_F_RAND_DRBG_GENERATE, RAND_R_GENERATE_ERROR);
632 drbg->reseed_gen_counter++;
638 * Generates |outlen| random bytes and stores them in |out|. It will
639 * using the given |drbg| to generate the bytes.
641 * Requires that drbg->lock is already locked for write, if non-null.
643 * Returns 1 on success 0 on failure.
645 int RAND_DRBG_bytes(RAND_DRBG *drbg, unsigned char *out, size_t outlen)
647 unsigned char *additional = NULL;
648 size_t additional_len;
652 additional_len = rand_drbg_get_additional_data(&additional, drbg->max_adinlen);
654 for ( ; outlen > 0; outlen -= chunk, out += chunk) {
656 if (chunk > drbg->max_request)
657 chunk = drbg->max_request;
658 ret = RAND_DRBG_generate(drbg, out, chunk, 0, additional, additional_len);
665 if (additional_len != 0)
666 OPENSSL_secure_clear_free(additional, additional_len);
672 * Set the RAND_DRBG callbacks for obtaining entropy and nonce.
674 * Setting the callbacks is allowed only if the drbg has not been
675 * initialized yet. Otherwise, the operation will fail.
677 * Returns 1 on success, 0 on failure.
679 int RAND_DRBG_set_callbacks(RAND_DRBG *drbg,
680 RAND_DRBG_get_entropy_fn get_entropy,
681 RAND_DRBG_cleanup_entropy_fn cleanup_entropy,
682 RAND_DRBG_get_nonce_fn get_nonce,
683 RAND_DRBG_cleanup_nonce_fn cleanup_nonce)
685 if (drbg->state != DRBG_UNINITIALISED
686 || drbg->parent != NULL)
688 drbg->get_entropy = get_entropy;
689 drbg->cleanup_entropy = cleanup_entropy;
690 drbg->get_nonce = get_nonce;
691 drbg->cleanup_nonce = cleanup_nonce;
696 * Set the reseed interval.
698 * The drbg will reseed automatically whenever the number of generate
699 * requests exceeds the given reseed interval. If the reseed interval
700 * is 0, then this feature is disabled.
702 * Returns 1 on success, 0 on failure.
704 int RAND_DRBG_set_reseed_interval(RAND_DRBG *drbg, unsigned int interval)
706 if (interval > MAX_RESEED_INTERVAL)
708 drbg->reseed_interval = interval;
713 * Set the reseed time interval.
715 * The drbg will reseed automatically whenever the time elapsed since
716 * the last reseeding exceeds the given reseed time interval. For safety,
717 * a reseeding will also occur if the clock has been reset to a smaller
720 * Returns 1 on success, 0 on failure.
722 int RAND_DRBG_set_reseed_time_interval(RAND_DRBG *drbg, time_t interval)
724 if (interval > MAX_RESEED_TIME_INTERVAL)
726 drbg->reseed_time_interval = interval;
731 * Set the default values for reseed (time) intervals of new DRBG instances
733 * The default values can be set independently for master DRBG instances
734 * (without a parent) and slave DRBG instances (with parent).
736 * Returns 1 on success, 0 on failure.
739 int RAND_DRBG_set_reseed_defaults(
740 unsigned int _master_reseed_interval,
741 unsigned int _slave_reseed_interval,
742 time_t _master_reseed_time_interval,
743 time_t _slave_reseed_time_interval
746 if (_master_reseed_interval > MAX_RESEED_INTERVAL
747 || _slave_reseed_interval > MAX_RESEED_INTERVAL)
750 if (_master_reseed_time_interval > MAX_RESEED_TIME_INTERVAL
751 || _slave_reseed_time_interval > MAX_RESEED_TIME_INTERVAL)
754 master_reseed_interval = _master_reseed_interval;
755 slave_reseed_interval = _slave_reseed_interval;
757 master_reseed_time_interval = _master_reseed_time_interval;
758 slave_reseed_time_interval = _slave_reseed_time_interval;
764 * Locks the given drbg. Locking a drbg which does not have locking
765 * enabled is considered a successful no-op.
767 * Returns 1 on success, 0 on failure.
769 int rand_drbg_lock(RAND_DRBG *drbg)
771 if (drbg->lock != NULL)
772 return CRYPTO_THREAD_write_lock(drbg->lock);
778 * Unlocks the given drbg. Unlocking a drbg which does not have locking
779 * enabled is considered a successful no-op.
781 * Returns 1 on success, 0 on failure.
783 int rand_drbg_unlock(RAND_DRBG *drbg)
785 if (drbg->lock != NULL)
786 return CRYPTO_THREAD_unlock(drbg->lock);
792 * Enables locking for the given drbg
794 * Locking can only be enabled if the random generator
795 * is in the uninitialized state.
797 * Returns 1 on success, 0 on failure.
799 int rand_drbg_enable_locking(RAND_DRBG *drbg)
801 if (drbg->state != DRBG_UNINITIALISED) {
802 RANDerr(RAND_F_RAND_DRBG_ENABLE_LOCKING,
803 RAND_R_DRBG_ALREADY_INITIALIZED);
807 if (drbg->lock == NULL) {
808 if (drbg->parent != NULL && drbg->parent->lock == NULL) {
809 RANDerr(RAND_F_RAND_DRBG_ENABLE_LOCKING,
810 RAND_R_PARENT_LOCKING_NOT_ENABLED);
814 drbg->lock = CRYPTO_THREAD_lock_new();
815 if (drbg->lock == NULL) {
816 RANDerr(RAND_F_RAND_DRBG_ENABLE_LOCKING,
817 RAND_R_FAILED_TO_CREATE_LOCK);
826 * Get and set the EXDATA
828 int RAND_DRBG_set_ex_data(RAND_DRBG *drbg, int idx, void *arg)
830 return CRYPTO_set_ex_data(&drbg->ex_data, idx, arg);
833 void *RAND_DRBG_get_ex_data(const RAND_DRBG *drbg, int idx)
835 return CRYPTO_get_ex_data(&drbg->ex_data, idx);
840 * The following functions provide a RAND_METHOD that works on the
841 * global DRBG. They lock.
845 * Allocates a new global DRBG on the secure heap (if enabled) and
846 * initializes it with default settings.
848 * Returns a pointer to the new DRBG instance on success, NULL on failure.
850 static RAND_DRBG *drbg_setup(RAND_DRBG *parent)
854 drbg = RAND_DRBG_secure_new(rand_drbg_type, rand_drbg_flags, parent);
858 /* Only the master DRBG needs to have a lock */
859 if (parent == NULL && rand_drbg_enable_locking(drbg) == 0)
862 /* enable seed propagation */
863 tsan_store(&drbg->reseed_prop_counter, 1);
866 * Ignore instantiation error to support just-in-time instantiation.
868 * The state of the drbg will be checked in RAND_DRBG_generate() and
869 * an automatic recovery is attempted.
871 (void)RAND_DRBG_instantiate(drbg,
872 (const unsigned char *) ossl_pers_string,
873 sizeof(ossl_pers_string) - 1);
877 RAND_DRBG_free(drbg);
882 * Initialize the global DRBGs on first use.
883 * Returns 1 on success, 0 on failure.
885 DEFINE_RUN_ONCE_STATIC(do_rand_drbg_init)
888 * ensure that libcrypto is initialized, otherwise the
889 * DRBG locks are not cleaned up properly
891 if (!OPENSSL_init_crypto(0, NULL))
894 if (!CRYPTO_THREAD_init_local(&private_drbg, NULL))
897 if (!CRYPTO_THREAD_init_local(&public_drbg, NULL))
900 master_drbg = drbg_setup(NULL);
901 if (master_drbg == NULL)
907 CRYPTO_THREAD_cleanup_local(&public_drbg);
909 CRYPTO_THREAD_cleanup_local(&private_drbg);
913 /* Clean up the global DRBGs before exit */
914 void rand_drbg_cleanup_int(void)
916 if (master_drbg != NULL) {
917 RAND_DRBG_free(master_drbg);
920 CRYPTO_THREAD_cleanup_local(&private_drbg);
921 CRYPTO_THREAD_cleanup_local(&public_drbg);
925 void drbg_delete_thread_state(void)
929 drbg = CRYPTO_THREAD_get_local(&public_drbg);
930 CRYPTO_THREAD_set_local(&public_drbg, NULL);
931 RAND_DRBG_free(drbg);
933 drbg = CRYPTO_THREAD_get_local(&private_drbg);
934 CRYPTO_THREAD_set_local(&private_drbg, NULL);
935 RAND_DRBG_free(drbg);
938 /* Implements the default OpenSSL RAND_bytes() method */
939 static int drbg_bytes(unsigned char *out, int count)
942 RAND_DRBG *drbg = RAND_DRBG_get0_public();
947 ret = RAND_DRBG_bytes(drbg, out, count);
953 * Calculates the minimum length of a full entropy buffer
954 * which is necessary to seed (i.e. instantiate) the DRBG
957 * NOTE: There is a copy of this function in drbgtest.c.
958 * If you change anything here, you need to update
959 * the copy accordingly.
961 static size_t rand_drbg_seedlen(RAND_DRBG *drbg)
964 * If no os entropy source is available then RAND_seed(buffer, bufsize)
965 * is expected to succeed if and only if the buffer length satisfies
966 * the following requirements, which follow from the calculations
967 * in RAND_DRBG_instantiate().
969 size_t min_entropy = drbg->strength;
970 size_t min_entropylen = drbg->min_entropylen;
973 * Extra entropy for the random nonce in the absence of a
974 * get_nonce callback, see comment in RAND_DRBG_instantiate().
976 if (drbg->min_noncelen > 0 && drbg->get_nonce == NULL) {
977 min_entropy += drbg->strength / 2;
978 min_entropylen += drbg->min_noncelen;
982 * Convert entropy requirement from bits to bytes
983 * (dividing by 8 without rounding upwards, because
984 * all entropy requirements are divisible by 8).
988 /* Return a value that satisfies both requirements */
989 return min_entropy > min_entropylen ? min_entropy : min_entropylen;
992 /* Implements the default OpenSSL RAND_add() method */
993 static int drbg_add(const void *buf, int num, double randomness)
996 RAND_DRBG *drbg = RAND_DRBG_get0_master();
1003 if (num < 0 || randomness < 0.0)
1006 rand_drbg_lock(drbg);
1007 seedlen = rand_drbg_seedlen(drbg);
1009 buflen = (size_t)num;
1011 if (buflen < seedlen || randomness < (double) seedlen) {
1012 #if defined(OPENSSL_RAND_SEED_NONE)
1014 * If no os entropy source is available, a reseeding will fail
1015 * inevitably. So we use a trick to mix the buffer contents into
1016 * the DRBG state without forcing a reseeding: we generate a
1017 * dummy random byte, using the buffer content as additional data.
1018 * Note: This won't work with RAND_DRBG_FLAG_CTR_NO_DF.
1020 unsigned char dummy[1];
1022 ret = RAND_DRBG_generate(drbg, dummy, sizeof(dummy), 0, buf, buflen);
1023 rand_drbg_unlock(drbg);
1027 * If an os entropy source is avaible then we declare the buffer content
1028 * as additional data by setting randomness to zero and trigger a regular
1036 if (randomness > (double)seedlen) {
1038 * The purpose of this check is to bound |randomness| by a
1039 * relatively small value in order to prevent an integer
1040 * overflow when multiplying by 8 in the rand_drbg_restart()
1041 * call below. Note that randomness is measured in bytes,
1042 * not bits, so this value corresponds to eight times the
1043 * security strength.
1045 randomness = (double)seedlen;
1048 ret = rand_drbg_restart(drbg, buf, buflen, (size_t)(8 * randomness));
1049 rand_drbg_unlock(drbg);
1054 /* Implements the default OpenSSL RAND_seed() method */
1055 static int drbg_seed(const void *buf, int num)
1057 return drbg_add(buf, num, num);
1060 /* Implements the default OpenSSL RAND_status() method */
1061 static int drbg_status(void)
1064 RAND_DRBG *drbg = RAND_DRBG_get0_master();
1069 rand_drbg_lock(drbg);
1070 ret = drbg->state == DRBG_READY ? 1 : 0;
1071 rand_drbg_unlock(drbg);
1076 * Get the master DRBG.
1077 * Returns pointer to the DRBG on success, NULL on failure.
1080 RAND_DRBG *RAND_DRBG_get0_master(void)
1082 if (!RUN_ONCE(&rand_drbg_init, do_rand_drbg_init))
1089 * Get the public DRBG.
1090 * Returns pointer to the DRBG on success, NULL on failure.
1092 RAND_DRBG *RAND_DRBG_get0_public(void)
1096 if (!RUN_ONCE(&rand_drbg_init, do_rand_drbg_init))
1099 drbg = CRYPTO_THREAD_get_local(&public_drbg);
1101 if (!ossl_init_thread_start(OPENSSL_INIT_THREAD_RAND))
1103 drbg = drbg_setup(master_drbg);
1104 CRYPTO_THREAD_set_local(&public_drbg, drbg);
1110 * Get the private DRBG.
1111 * Returns pointer to the DRBG on success, NULL on failure.
1113 RAND_DRBG *RAND_DRBG_get0_private(void)
1117 if (!RUN_ONCE(&rand_drbg_init, do_rand_drbg_init))
1120 drbg = CRYPTO_THREAD_get_local(&private_drbg);
1122 if (!ossl_init_thread_start(OPENSSL_INIT_THREAD_RAND))
1124 drbg = drbg_setup(master_drbg);
1125 CRYPTO_THREAD_set_local(&private_drbg, drbg);
1130 RAND_METHOD rand_meth = {
1139 RAND_METHOD *RAND_OpenSSL(void)