2 * Copyright 2011-2017 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"
19 * Support framework for NIST SP 800-90A DRBG, AES-CTR mode.
20 * The RAND_DRBG is OpenSSL's pointer to an instance of the DRBG.
22 * The OpenSSL model is to have new and free functions, and that new
23 * does all initialization. That is not the NIST model, which has
24 * instantiation and un-instantiate, and re-use within a new/free
25 * lifecycle. (No doubt this comes from the desire to support hardware
26 * DRBG, where allocation of resources on something like an HSM is
27 * a much bigger deal than just re-setting an allocated resource.)
31 * THE THREE SHARED DRBGs
33 * There are three shared DRBGs (master, public and private), which are
34 * accessed concurrently by all threads.
38 * Not used directly by the application, only for reseeding the two other
39 * DRBGs. It reseeds itself by pulling either randomness from os entropy
40 * sources or by consuming randomnes which was added by RAND_add()
42 static RAND_DRBG *drbg_master;
46 * Used by default for generating random bytes using RAND_bytes().
48 static RAND_DRBG *drbg_public;
52 * Used by default for generating private keys using RAND_priv_bytes()
54 static RAND_DRBG *drbg_private;
58 * In addition there are DRBGs, which are not shared, but used only by a
59 * single thread at every time, for example the DRBGs which are owned by
60 * an SSL context. All DRBGs are organized in a hierarchical fashion
61 * with the <master> DRBG as root.
63 * This gives the following overall picture:
65 * <os entropy sources>
67 * RAND_add() ==> <master> \
68 * / \ | shared DRBGs (with locking)
69 * <public> <private> /
71 * <ssl> owned by an SSL context
75 * Before satisfying a generate request, a DRBG reseeds itself automatically,
76 * if one of the following two conditions holds:
78 * - the number of generate requests since the last reseeding exceeds a
79 * certain threshold, the so called |reseed_interval|. This behaviour
80 * can be disabled by setting the |reseed_interval| to 0.
82 * - the time elapsed since the last reseeding exceeds a certain time
83 * interval, the so called |reseed_time_interval|. This behaviour
84 * can be disabled by setting the |reseed_time_interval| to 0.
88 * For the three shared DRBGs (and only for these) there is another way to
89 * reseed them manually by calling RAND_seed() (or RAND_add() with a positive
90 * |randomness| argument). This will immediately reseed the <master> DRBG.
91 * The <public> and <private> DRBG will detect this on their next generate
92 * call and reseed, pulling randomness from <master>.
96 /* NIST SP 800-90A DRBG recommends the use of a personalization string. */
97 static const char ossl_pers_string[] = "OpenSSL NIST SP 800-90A DRBG";
99 static CRYPTO_ONCE rand_drbg_init = CRYPTO_ONCE_STATIC_INIT;
101 static RAND_DRBG *drbg_setup(const char *name, RAND_DRBG *parent);
102 static void drbg_cleanup(RAND_DRBG *drbg);
105 * Set/initialize |drbg| to be of type |nid|, with optional |flags|.
106 * Return -2 if the type is not supported, 1 on success and -1 on
109 int RAND_DRBG_set(RAND_DRBG *drbg, int nid, unsigned int flags)
113 drbg->state = DRBG_UNINITIALISED;
119 RANDerr(RAND_F_RAND_DRBG_SET, RAND_R_UNSUPPORTED_DRBG_TYPE);
122 /* Uninitialized; that's okay. */
124 case NID_aes_128_ctr:
125 case NID_aes_192_ctr:
126 case NID_aes_256_ctr:
127 ret = ctr_init(drbg);
132 RANDerr(RAND_F_RAND_DRBG_SET, RAND_R_ERROR_INITIALISING_DRBG);
137 * Allocate memory and initialize a new DRBG. The |parent|, if not
138 * NULL, will be used to auto-seed this RAND_DRBG as needed.
140 * Returns a pointer to the new DRBG instance on success, NULL on failure.
142 RAND_DRBG *RAND_DRBG_new(int type, unsigned int flags, RAND_DRBG *parent)
144 RAND_DRBG *drbg = OPENSSL_zalloc(sizeof(*drbg));
147 RANDerr(RAND_F_RAND_DRBG_NEW, ERR_R_MALLOC_FAILURE);
150 drbg->fork_count = rand_fork_count;
151 drbg->parent = parent;
152 if (RAND_DRBG_set(drbg, type, flags) < 0)
155 if (!RAND_DRBG_set_callbacks(drbg, rand_drbg_get_entropy,
156 rand_drbg_cleanup_entropy,
168 * Uninstantiate |drbg| and free all memory.
170 void RAND_DRBG_free(RAND_DRBG *drbg)
175 ctr_uninstantiate(drbg);
176 CRYPTO_free_ex_data(CRYPTO_EX_INDEX_DRBG, drbg, &drbg->ex_data);
177 OPENSSL_clear_free(drbg, sizeof(*drbg));
181 * Instantiate |drbg|, after it has been initialized. Use |pers| and
182 * |perslen| as prediction-resistance input.
184 * Requires that drbg->lock is already locked for write, if non-null.
186 int RAND_DRBG_instantiate(RAND_DRBG *drbg,
187 const unsigned char *pers, size_t perslen)
189 unsigned char *nonce = NULL, *entropy = NULL;
190 size_t noncelen = 0, entropylen = 0;
192 if (perslen > drbg->max_perslen) {
193 RANDerr(RAND_F_RAND_DRBG_INSTANTIATE,
194 RAND_R_PERSONALISATION_STRING_TOO_LONG);
197 if (drbg->state != DRBG_UNINITIALISED) {
198 RANDerr(RAND_F_RAND_DRBG_INSTANTIATE,
199 drbg->state == DRBG_ERROR ? RAND_R_IN_ERROR_STATE
200 : RAND_R_ALREADY_INSTANTIATED);
204 drbg->state = DRBG_ERROR;
205 if (drbg->get_entropy != NULL)
206 entropylen = drbg->get_entropy(drbg, &entropy, drbg->strength,
207 drbg->min_entropylen, drbg->max_entropylen);
208 if (entropylen < drbg->min_entropylen
209 || entropylen > drbg->max_entropylen) {
210 RANDerr(RAND_F_RAND_DRBG_INSTANTIATE, RAND_R_ERROR_RETRIEVING_ENTROPY);
214 if (drbg->max_noncelen > 0 && drbg->get_nonce != NULL) {
215 noncelen = drbg->get_nonce(drbg, &nonce, drbg->strength / 2,
216 drbg->min_noncelen, drbg->max_noncelen);
217 if (noncelen < drbg->min_noncelen || noncelen > drbg->max_noncelen) {
218 RANDerr(RAND_F_RAND_DRBG_INSTANTIATE,
219 RAND_R_ERROR_RETRIEVING_NONCE);
224 if (!ctr_instantiate(drbg, entropy, entropylen,
225 nonce, noncelen, pers, perslen)) {
226 RANDerr(RAND_F_RAND_DRBG_INSTANTIATE, RAND_R_ERROR_INSTANTIATING_DRBG);
230 drbg->state = DRBG_READY;
231 drbg->generate_counter = 0;
232 drbg->reseed_time = time(NULL);
233 if (drbg->reseed_counter > 0) {
234 if (drbg->parent == NULL)
235 drbg->reseed_counter++;
237 drbg->reseed_counter = drbg->parent->reseed_counter;
241 if (entropy != NULL && drbg->cleanup_entropy != NULL)
242 drbg->cleanup_entropy(drbg, entropy, entropylen);
243 if (nonce != NULL && drbg->cleanup_nonce!= NULL )
244 drbg->cleanup_nonce(drbg, nonce, noncelen);
245 if (drbg->pool != NULL) {
246 if (drbg->state == DRBG_READY) {
247 RANDerr(RAND_F_RAND_DRBG_INSTANTIATE,
248 RAND_R_ERROR_ENTROPY_POOL_WAS_IGNORED);
249 drbg->state = DRBG_ERROR;
251 RAND_POOL_free(drbg->pool);
254 if (drbg->state == DRBG_READY)
260 * Uninstantiate |drbg|. Must be instantiated before it can be used.
262 * Requires that drbg->lock is already locked for write, if non-null.
264 int RAND_DRBG_uninstantiate(RAND_DRBG *drbg)
266 int ret = ctr_uninstantiate(drbg);
268 drbg->state = DRBG_UNINITIALISED;
273 * Reseed |drbg|, mixing in the specified data
275 * Requires that drbg->lock is already locked for write, if non-null.
277 int RAND_DRBG_reseed(RAND_DRBG *drbg,
278 const unsigned char *adin, size_t adinlen)
280 unsigned char *entropy = NULL;
281 size_t entropylen = 0;
283 if (drbg->state == DRBG_ERROR) {
284 RANDerr(RAND_F_RAND_DRBG_RESEED, RAND_R_IN_ERROR_STATE);
287 if (drbg->state == DRBG_UNINITIALISED) {
288 RANDerr(RAND_F_RAND_DRBG_RESEED, RAND_R_NOT_INSTANTIATED);
294 else if (adinlen > drbg->max_adinlen) {
295 RANDerr(RAND_F_RAND_DRBG_RESEED, RAND_R_ADDITIONAL_INPUT_TOO_LONG);
299 drbg->state = DRBG_ERROR;
300 if (drbg->get_entropy != NULL)
301 entropylen = drbg->get_entropy(drbg, &entropy, drbg->strength,
302 drbg->min_entropylen, drbg->max_entropylen);
303 if (entropylen < drbg->min_entropylen
304 || entropylen > drbg->max_entropylen) {
305 RANDerr(RAND_F_RAND_DRBG_RESEED, RAND_R_ERROR_RETRIEVING_ENTROPY);
309 if (!ctr_reseed(drbg, entropy, entropylen, adin, adinlen))
312 drbg->state = DRBG_READY;
313 drbg->generate_counter = 0;
314 drbg->reseed_time = time(NULL);
315 if (drbg->reseed_counter > 0) {
316 if (drbg->parent == NULL)
317 drbg->reseed_counter++;
319 drbg->reseed_counter = drbg->parent->reseed_counter;
323 if (entropy != NULL && drbg->cleanup_entropy != NULL)
324 drbg->cleanup_entropy(drbg, entropy, entropylen);
325 if (drbg->state == DRBG_READY)
331 * Restart |drbg|, using the specified entropy or additional input
333 * Tries its best to get the drbg instantiated by all means,
334 * regardless of its current state.
336 * Optionally, a |buffer| of |len| random bytes can be passed,
337 * which is assumed to contain at least |entropy| bits of entropy.
339 * If |entropy| > 0, the buffer content is used as entropy input.
341 * If |entropy| == 0, the buffer content is used as additional input
343 * Returns 1 on success, 0 on failure.
345 * This function is used internally only.
347 int rand_drbg_restart(RAND_DRBG *drbg,
348 const unsigned char *buffer, size_t len, size_t entropy)
351 const unsigned char *adin = NULL;
354 if (drbg->pool != NULL) {
355 RANDerr(RAND_F_RAND_DRBG_RESTART, ERR_R_INTERNAL_ERROR);
356 RAND_POOL_free(drbg->pool);
360 if (buffer != NULL) {
362 if (drbg->max_entropylen < len) {
363 RANDerr(RAND_F_RAND_DRBG_RESTART,
364 RAND_R_ENTROPY_INPUT_TOO_LONG);
368 if (entropy > 8 * len) {
369 RANDerr(RAND_F_RAND_DRBG_RESTART, RAND_R_ENTROPY_OUT_OF_RANGE);
373 /* will be picked up by the rand_drbg_get_entropy() callback */
374 drbg->pool = RAND_POOL_new(entropy, len, len);
375 if (drbg->pool == NULL)
378 RAND_POOL_add(drbg->pool, buffer, len, entropy);
380 if (drbg->max_adinlen < len) {
381 RANDerr(RAND_F_RAND_DRBG_RESTART,
382 RAND_R_ADDITIONAL_INPUT_TOO_LONG);
390 /* repair error state */
391 if (drbg->state == DRBG_ERROR) {
392 RAND_DRBG_uninstantiate(drbg);
393 /* The drbg->ctr member needs to be reinitialized before reinstantiation */
394 RAND_DRBG_set(drbg, drbg->nid, drbg->flags);
397 /* repair uninitialized state */
398 if (drbg->state == DRBG_UNINITIALISED) {
399 /* reinstantiate drbg */
400 RAND_DRBG_instantiate(drbg,
401 (const unsigned char *) ossl_pers_string,
402 sizeof(ossl_pers_string) - 1);
403 /* already reseeded. prevent second reseeding below */
404 reseeded = (drbg->state == DRBG_READY);
407 /* refresh current state if entropy or additional input has been provided */
408 if (drbg->state == DRBG_READY) {
411 * mix in additional input without reseeding
413 * Similar to RAND_DRBG_reseed(), but the provided additional
414 * data |adin| is mixed into the current state without pulling
415 * entropy from the trusted entropy source using get_entropy().
416 * This is not a reseeding in the strict sense of NIST SP 800-90A.
418 ctr_reseed(drbg, adin, adinlen, NULL, 0);
419 } else if (reseeded == 0) {
420 /* do a full reseeding if it has not been done yet above */
421 RAND_DRBG_reseed(drbg, NULL, 0);
425 /* check whether a given entropy pool was cleared properly during reseed */
426 if (drbg->pool != NULL) {
427 drbg->state = DRBG_ERROR;
428 RANDerr(RAND_F_RAND_DRBG_RESTART, ERR_R_INTERNAL_ERROR);
429 RAND_POOL_free(drbg->pool);
434 return drbg->state == DRBG_READY;
438 * Generate |outlen| bytes into the buffer at |out|. Reseed if we need
439 * to or if |prediction_resistance| is set. Additional input can be
440 * sent in |adin| and |adinlen|.
442 * Requires that drbg->lock is already locked for write, if non-null.
444 * Returns 1 on success, 0 on failure.
447 int RAND_DRBG_generate(RAND_DRBG *drbg, unsigned char *out, size_t outlen,
448 int prediction_resistance,
449 const unsigned char *adin, size_t adinlen)
451 int reseed_required = 0;
453 if (drbg->state != DRBG_READY) {
454 /* try to recover from previous errors */
455 rand_drbg_restart(drbg, NULL, 0, 0);
457 if (drbg->state == DRBG_ERROR) {
458 RANDerr(RAND_F_RAND_DRBG_GENERATE, RAND_R_IN_ERROR_STATE);
461 if (drbg->state == DRBG_UNINITIALISED) {
462 RANDerr(RAND_F_RAND_DRBG_GENERATE, RAND_R_NOT_INSTANTIATED);
467 if (outlen > drbg->max_request) {
468 RANDerr(RAND_F_RAND_DRBG_GENERATE, RAND_R_REQUEST_TOO_LARGE_FOR_DRBG);
471 if (adinlen > drbg->max_adinlen) {
472 RANDerr(RAND_F_RAND_DRBG_GENERATE, RAND_R_ADDITIONAL_INPUT_TOO_LONG);
476 if (drbg->fork_count != rand_fork_count) {
477 drbg->fork_count = rand_fork_count;
481 if (drbg->reseed_interval > 0) {
482 if (drbg->generate_counter >= drbg->reseed_interval)
485 if (drbg->reseed_time_interval > 0) {
486 time_t now = time(NULL);
487 if (now < drbg->reseed_time
488 || now - drbg->reseed_time >= drbg->reseed_time_interval)
491 if (drbg->reseed_counter > 0 && drbg->parent != NULL) {
492 if (drbg->reseed_counter != drbg->parent->reseed_counter)
496 if (reseed_required || prediction_resistance) {
497 if (!RAND_DRBG_reseed(drbg, adin, adinlen)) {
498 RANDerr(RAND_F_RAND_DRBG_GENERATE, RAND_R_RESEED_ERROR);
505 if (!ctr_generate(drbg, out, outlen, adin, adinlen)) {
506 drbg->state = DRBG_ERROR;
507 RANDerr(RAND_F_RAND_DRBG_GENERATE, RAND_R_GENERATE_ERROR);
511 drbg->generate_counter++;
517 * Set the RAND_DRBG callbacks for obtaining entropy and nonce.
519 * In the following, the signature and the semantics of the
520 * get_entropy() and cleanup_entropy() callbacks are explained.
524 * size_t get_entropy(RAND_DRBG *ctx,
525 * unsigned char **pout,
527 * size_t min_len, size_t max_len);
529 * This is a request to allocate and fill a buffer of size
530 * |min_len| <= size <= |max_len| (in bytes) which contains
531 * at least |entropy| bits of randomness. The buffer's address is
532 * to be returned in |*pout| and the number of collected
533 * randomness bytes (which may be less than the allocated size
534 * of the buffer) as return value.
536 * If the callback fails to acquire at least |entropy| bits of
537 * randomness, it shall return a buffer length of 0.
541 * void cleanup_entropy(RAND_DRBG *ctx,
542 * unsigned char *out, size_t outlen);
544 * A request to clear and free the buffer allocated by get_entropy().
545 * The values |out| and |outlen| are expected to be the random buffer's
546 * address and length, as returned by the get_entropy() callback.
548 * GET_NONCE, CLEANUP_NONCE
550 * Signature and semantics of the get_nonce() and cleanup_nonce()
551 * callbacks are analogous to get_entropy() and cleanup_entropy().
552 * Currently, the nonce is used only for the known answer tests.
554 int RAND_DRBG_set_callbacks(RAND_DRBG *drbg,
555 RAND_DRBG_get_entropy_fn get_entropy,
556 RAND_DRBG_cleanup_entropy_fn cleanup_entropy,
557 RAND_DRBG_get_nonce_fn get_nonce,
558 RAND_DRBG_cleanup_nonce_fn cleanup_nonce)
560 if (drbg->state != DRBG_UNINITIALISED)
562 drbg->get_entropy = get_entropy;
563 drbg->cleanup_entropy = cleanup_entropy;
564 drbg->get_nonce = get_nonce;
565 drbg->cleanup_nonce = cleanup_nonce;
570 * Set the reseed interval.
572 * The drbg will reseed automatically whenever the number of generate
573 * requests exceeds the given reseed interval. If the reseed interval
574 * is 0, then this feature is disabled.
576 * Returns 1 on success, 0 on failure.
578 int RAND_DRBG_set_reseed_interval(RAND_DRBG *drbg, unsigned int interval)
580 if (interval > MAX_RESEED_INTERVAL)
582 drbg->reseed_interval = interval;
587 * Set the reseed time interval.
589 * The drbg will reseed automatically whenever the time elapsed since
590 * the last reseeding exceeds the given reseed time interval. For safety,
591 * a reseeding will also occur if the clock has been reset to a smaller
594 * Returns 1 on success, 0 on failure.
596 int RAND_DRBG_set_reseed_time_interval(RAND_DRBG *drbg, time_t interval)
598 if (interval > MAX_RESEED_TIME_INTERVAL)
600 drbg->reseed_time_interval = interval;
605 * Get and set the EXDATA
607 int RAND_DRBG_set_ex_data(RAND_DRBG *drbg, int idx, void *arg)
609 return CRYPTO_set_ex_data(&drbg->ex_data, idx, arg);
612 void *RAND_DRBG_get_ex_data(const RAND_DRBG *drbg, int idx)
614 return CRYPTO_get_ex_data(&drbg->ex_data, idx);
619 * The following functions provide a RAND_METHOD that works on the
620 * global DRBG. They lock.
624 * Allocates a new global DRBG on the secure heap (if enabled) and
625 * initializes it with default settings.
626 * A global lock for the DRBG is created with the given name.
628 * Returns a pointer to the new DRBG instance on success, NULL on failure.
630 static RAND_DRBG *drbg_setup(const char *name, RAND_DRBG *parent)
635 RANDerr(RAND_F_DRBG_SETUP, ERR_R_INTERNAL_ERROR);
639 drbg = OPENSSL_secure_zalloc(sizeof(RAND_DRBG));
643 drbg->lock = CRYPTO_THREAD_glock_new(name);
644 if (drbg->lock == NULL) {
645 RANDerr(RAND_F_DRBG_SETUP, RAND_R_FAILED_TO_CREATE_LOCK);
649 if (RAND_DRBG_set(drbg,
650 RAND_DRBG_NID, RAND_DRBG_FLAG_CTR_USE_DF) != 1)
652 if (RAND_DRBG_set_callbacks(drbg, rand_drbg_get_entropy,
653 rand_drbg_cleanup_entropy, NULL, NULL) != 1)
656 if (parent == NULL) {
657 drbg->reseed_interval = MASTER_RESEED_INTERVAL;
658 drbg->reseed_time_interval = MASTER_RESEED_TIME_INTERVAL;
660 drbg->parent = parent;
661 drbg->reseed_interval = SLAVE_RESEED_INTERVAL;
662 drbg->reseed_time_interval = SLAVE_RESEED_TIME_INTERVAL;
665 /* enable seed propagation */
666 drbg->reseed_counter = 1;
669 * Ignore instantiation error so support just-in-time instantiation.
671 * The state of the drbg will be checked in RAND_DRBG_generate() and
672 * an automatic recovery is attempted.
674 RAND_DRBG_instantiate(drbg,
675 (const unsigned char *) ossl_pers_string,
676 sizeof(ossl_pers_string) - 1);
685 * Initialize the global DRBGs on first use.
686 * Returns 1 on success, 0 on failure.
688 DEFINE_RUN_ONCE_STATIC(do_rand_drbg_init)
690 drbg_master = drbg_setup("drbg_master", NULL);
691 drbg_public = drbg_setup("drbg_public", drbg_master);
692 drbg_private = drbg_setup("drbg_private", drbg_master);
694 if (drbg_master == NULL || drbg_public == NULL || drbg_private == NULL)
700 /* Cleans up the given global DRBG */
701 static void drbg_cleanup(RAND_DRBG *drbg)
704 RAND_DRBG_uninstantiate(drbg);
705 CRYPTO_THREAD_lock_free(drbg->lock);
706 OPENSSL_secure_clear_free(drbg, sizeof(RAND_DRBG));
710 /* Clean up the global DRBGs before exit */
711 void rand_drbg_cleanup_int(void)
713 drbg_cleanup(drbg_private);
714 drbg_cleanup(drbg_public);
715 drbg_cleanup(drbg_master);
717 drbg_private = drbg_public = drbg_master = NULL;
720 /* Implements the default OpenSSL RAND_bytes() method */
721 static int drbg_bytes(unsigned char *out, int count)
725 RAND_DRBG *drbg = RAND_DRBG_get0_public();
730 CRYPTO_THREAD_write_lock(drbg->lock);
731 if (drbg->state == DRBG_UNINITIALISED)
734 for ( ; count > 0; count -= chunk, out += chunk) {
736 if (chunk > drbg->max_request)
737 chunk = drbg->max_request;
738 ret = RAND_DRBG_generate(drbg, out, chunk, 0, NULL, 0);
745 CRYPTO_THREAD_unlock(drbg->lock);
749 /* Implements the default OpenSSL RAND_add() method */
750 static int drbg_add(const void *buf, int num, double randomness)
753 RAND_DRBG *drbg = RAND_DRBG_get0_master();
758 if (num < 0 || randomness < 0.0)
761 if (randomness > (double)drbg->max_entropylen) {
763 * The purpose of this check is to bound |randomness| by a
764 * relatively small value in order to prevent an integer
765 * overflow when multiplying by 8 in the rand_drbg_restart()
771 CRYPTO_THREAD_write_lock(drbg->lock);
772 ret = rand_drbg_restart(drbg, buf,
773 (size_t)(unsigned int)num,
774 (size_t)(8*randomness));
775 CRYPTO_THREAD_unlock(drbg->lock);
780 /* Implements the default OpenSSL RAND_seed() method */
781 static int drbg_seed(const void *buf, int num)
783 return drbg_add(buf, num, num);
786 /* Implements the default OpenSSL RAND_status() method */
787 static int drbg_status(void)
790 RAND_DRBG *drbg = RAND_DRBG_get0_master();
795 CRYPTO_THREAD_write_lock(drbg->lock);
796 ret = drbg->state == DRBG_READY ? 1 : 0;
797 CRYPTO_THREAD_unlock(drbg->lock);
802 * Get the master DRBG.
803 * Returns pointer to the DRBG on success, NULL on failure.
806 RAND_DRBG *RAND_DRBG_get0_master(void)
808 if (!RUN_ONCE(&rand_drbg_init, do_rand_drbg_init))
815 * Get the public DRBG.
816 * Returns pointer to the DRBG on success, NULL on failure.
818 RAND_DRBG *RAND_DRBG_get0_public(void)
820 if (!RUN_ONCE(&rand_drbg_init, do_rand_drbg_init))
827 * Get the private DRBG.
828 * Returns pointer to the DRBG on success, NULL on failure.
830 RAND_DRBG *RAND_DRBG_get0_private(void)
832 if (!RUN_ONCE(&rand_drbg_init, do_rand_drbg_init))
838 RAND_METHOD rand_meth = {
847 RAND_METHOD *RAND_OpenSSL(void)