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;
75 #define RAND_DRBG_TYPE_FLAGS ( \
76 RAND_DRBG_FLAG_MASTER | RAND_DRBG_FLAG_PUBLIC | RAND_DRBG_FLAG_PRIVATE )
78 #define RAND_DRBG_TYPE_MASTER 0
79 #define RAND_DRBG_TYPE_PUBLIC 1
80 #define RAND_DRBG_TYPE_PRIVATE 2
83 static int rand_drbg_type[3] = {
84 RAND_DRBG_TYPE, /* Master */
85 RAND_DRBG_TYPE, /* Public */
86 RAND_DRBG_TYPE /* Private */
88 static unsigned int rand_drbg_flags[3] = {
89 RAND_DRBG_FLAGS | RAND_DRBG_FLAG_MASTER, /* Master */
90 RAND_DRBG_FLAGS | RAND_DRBG_FLAG_PUBLIC, /* Public */
91 RAND_DRBG_FLAGS | RAND_DRBG_FLAG_PRIVATE /* Private */
94 static unsigned int master_reseed_interval = MASTER_RESEED_INTERVAL;
95 static unsigned int slave_reseed_interval = SLAVE_RESEED_INTERVAL;
97 static time_t master_reseed_time_interval = MASTER_RESEED_TIME_INTERVAL;
98 static time_t slave_reseed_time_interval = SLAVE_RESEED_TIME_INTERVAL;
100 /* A logical OR of all used DRBG flag bits (currently there is only one) */
101 static const unsigned int rand_drbg_used_flags =
102 RAND_DRBG_FLAG_CTR_NO_DF | RAND_DRBG_FLAG_HMAC | RAND_DRBG_TYPE_FLAGS;
105 static RAND_DRBG *drbg_setup(RAND_DRBG *parent, int drbg_type);
107 static RAND_DRBG *rand_drbg_new(int secure,
112 static int is_ctr(int type)
115 case NID_aes_128_ctr:
116 case NID_aes_192_ctr:
117 case NID_aes_256_ctr:
124 static int is_digest(int type)
145 * Set/initialize |drbg| to be of type |type|, with optional |flags|.
147 * If |type| and |flags| are zero, use the defaults
149 * Returns 1 on success, 0 on failure.
151 int RAND_DRBG_set(RAND_DRBG *drbg, int type, unsigned int flags)
155 if (type == 0 && flags == 0) {
156 type = rand_drbg_type[RAND_DRBG_TYPE_MASTER];
157 flags = rand_drbg_flags[RAND_DRBG_TYPE_MASTER];
160 /* If set is called multiple times - clear the old one */
161 if (drbg->type != 0 && (type != drbg->type || flags != drbg->flags)) {
162 drbg->meth->uninstantiate(drbg);
163 rand_pool_free(drbg->adin_pool);
164 drbg->adin_pool = NULL;
167 drbg->state = DRBG_UNINITIALISED;
172 /* Uninitialized; that's okay. */
175 } else if (is_ctr(type)) {
176 ret = drbg_ctr_init(drbg);
177 } else if (is_digest(type)) {
178 if (flags & RAND_DRBG_FLAG_HMAC)
179 ret = drbg_hmac_init(drbg);
181 ret = drbg_hash_init(drbg);
186 RANDerr(RAND_F_RAND_DRBG_SET, RAND_R_UNSUPPORTED_DRBG_TYPE);
191 drbg->state = DRBG_ERROR;
192 RANDerr(RAND_F_RAND_DRBG_SET, RAND_R_ERROR_INITIALISING_DRBG);
198 * Set/initialize default |type| and |flag| for new drbg instances.
200 * Returns 1 on success, 0 on failure.
202 int RAND_DRBG_set_defaults(int type, unsigned int flags)
205 if (!(is_digest(type) || is_ctr(type))) {
206 RANDerr(RAND_F_RAND_DRBG_SET_DEFAULTS, RAND_R_UNSUPPORTED_DRBG_TYPE);
210 if ((flags & ~rand_drbg_used_flags) != 0) {
211 RANDerr(RAND_F_RAND_DRBG_SET_DEFAULTS, RAND_R_UNSUPPORTED_DRBG_FLAGS);
215 all = ((flags & RAND_DRBG_TYPE_FLAGS) == 0);
216 if (all || (flags & RAND_DRBG_FLAG_MASTER) != 0) {
217 rand_drbg_type[RAND_DRBG_TYPE_MASTER] = type;
218 rand_drbg_flags[RAND_DRBG_TYPE_MASTER] = flags | RAND_DRBG_FLAG_MASTER;
220 if (all || (flags & RAND_DRBG_FLAG_PUBLIC) != 0) {
221 rand_drbg_type[RAND_DRBG_TYPE_PUBLIC] = type;
222 rand_drbg_flags[RAND_DRBG_TYPE_PUBLIC] = flags | RAND_DRBG_FLAG_PUBLIC;
224 if (all || (flags & RAND_DRBG_FLAG_PRIVATE) != 0) {
225 rand_drbg_type[RAND_DRBG_TYPE_PRIVATE] = type;
226 rand_drbg_flags[RAND_DRBG_TYPE_PRIVATE] = flags | RAND_DRBG_FLAG_PRIVATE;
233 * Allocate memory and initialize a new DRBG. The DRBG is allocated on
234 * the secure heap if |secure| is nonzero and the secure heap is enabled.
235 * The |parent|, if not NULL, will be used as random source for reseeding.
237 * Returns a pointer to the new DRBG instance on success, NULL on failure.
239 static RAND_DRBG *rand_drbg_new(int secure,
244 RAND_DRBG *drbg = secure ?
245 OPENSSL_secure_zalloc(sizeof(*drbg)) : OPENSSL_zalloc(sizeof(*drbg));
248 RANDerr(RAND_F_RAND_DRBG_NEW, ERR_R_MALLOC_FAILURE);
252 drbg->secure = secure && CRYPTO_secure_allocated(drbg);
253 drbg->fork_count = rand_fork_count;
254 drbg->parent = parent;
256 if (parent == NULL) {
257 drbg->get_entropy = rand_drbg_get_entropy;
258 drbg->cleanup_entropy = rand_drbg_cleanup_entropy;
259 #ifndef RAND_DRBG_GET_RANDOM_NONCE
260 drbg->get_nonce = rand_drbg_get_nonce;
261 drbg->cleanup_nonce = rand_drbg_cleanup_nonce;
264 drbg->reseed_interval = master_reseed_interval;
265 drbg->reseed_time_interval = master_reseed_time_interval;
267 drbg->get_entropy = rand_drbg_get_entropy;
268 drbg->cleanup_entropy = rand_drbg_cleanup_entropy;
270 * Do not provide nonce callbacks, the child DRBGs will
271 * obtain their nonce using random bits from the parent.
274 drbg->reseed_interval = slave_reseed_interval;
275 drbg->reseed_time_interval = slave_reseed_time_interval;
278 if (RAND_DRBG_set(drbg, type, flags) == 0)
281 if (parent != NULL) {
282 rand_drbg_lock(parent);
283 if (drbg->strength > parent->strength) {
285 * We currently don't support the algorithm from NIST SP 800-90C
286 * 10.1.2 to use a weaker DRBG as source
288 rand_drbg_unlock(parent);
289 RANDerr(RAND_F_RAND_DRBG_NEW, RAND_R_PARENT_STRENGTH_TOO_WEAK);
292 rand_drbg_unlock(parent);
298 RAND_DRBG_free(drbg);
303 RAND_DRBG *RAND_DRBG_new(int type, unsigned int flags, RAND_DRBG *parent)
305 return rand_drbg_new(0, type, flags, parent);
308 RAND_DRBG *RAND_DRBG_secure_new(int type, unsigned int flags, RAND_DRBG *parent)
310 return rand_drbg_new(1, type, flags, parent);
314 * Uninstantiate |drbg| and free all memory.
316 void RAND_DRBG_free(RAND_DRBG *drbg)
321 if (drbg->meth != NULL)
322 drbg->meth->uninstantiate(drbg);
323 rand_pool_free(drbg->adin_pool);
324 CRYPTO_THREAD_lock_free(drbg->lock);
325 CRYPTO_free_ex_data(CRYPTO_EX_INDEX_DRBG, drbg, &drbg->ex_data);
328 OPENSSL_secure_clear_free(drbg, sizeof(*drbg));
330 OPENSSL_clear_free(drbg, sizeof(*drbg));
334 * Instantiate |drbg|, after it has been initialized. Use |pers| and
335 * |perslen| as prediction-resistance input.
337 * Requires that drbg->lock is already locked for write, if non-null.
339 * Returns 1 on success, 0 on failure.
341 int RAND_DRBG_instantiate(RAND_DRBG *drbg,
342 const unsigned char *pers, size_t perslen)
344 unsigned char *nonce = NULL, *entropy = NULL;
345 size_t noncelen = 0, entropylen = 0;
346 size_t min_entropy = drbg->strength;
347 size_t min_entropylen = drbg->min_entropylen;
348 size_t max_entropylen = drbg->max_entropylen;
350 if (perslen > drbg->max_perslen) {
351 RANDerr(RAND_F_RAND_DRBG_INSTANTIATE,
352 RAND_R_PERSONALISATION_STRING_TOO_LONG);
356 if (drbg->meth == NULL) {
357 RANDerr(RAND_F_RAND_DRBG_INSTANTIATE,
358 RAND_R_NO_DRBG_IMPLEMENTATION_SELECTED);
362 if (drbg->state != DRBG_UNINITIALISED) {
363 RANDerr(RAND_F_RAND_DRBG_INSTANTIATE,
364 drbg->state == DRBG_ERROR ? RAND_R_IN_ERROR_STATE
365 : RAND_R_ALREADY_INSTANTIATED);
369 drbg->state = DRBG_ERROR;
372 * NIST SP800-90Ar1 section 9.1 says you can combine getting the entropy
373 * and nonce in 1 call by increasing the entropy with 50% and increasing
374 * the minimum length to accomadate the length of the nonce.
375 * We do this in case a nonce is require and get_nonce is NULL.
377 if (drbg->min_noncelen > 0 && drbg->get_nonce == NULL) {
378 min_entropy += drbg->strength / 2;
379 min_entropylen += drbg->min_noncelen;
380 max_entropylen += drbg->max_noncelen;
383 drbg->reseed_next_counter = tsan_load(&drbg->reseed_prop_counter);
384 if (drbg->reseed_next_counter) {
385 drbg->reseed_next_counter++;
386 if(!drbg->reseed_next_counter)
387 drbg->reseed_next_counter = 1;
390 if (drbg->get_entropy != NULL)
391 entropylen = drbg->get_entropy(drbg, &entropy, min_entropy,
392 min_entropylen, max_entropylen, 0);
393 if (entropylen < min_entropylen
394 || entropylen > max_entropylen) {
395 RANDerr(RAND_F_RAND_DRBG_INSTANTIATE, RAND_R_ERROR_RETRIEVING_ENTROPY);
399 if (drbg->min_noncelen > 0 && drbg->get_nonce != NULL) {
400 noncelen = drbg->get_nonce(drbg, &nonce, drbg->strength / 2,
401 drbg->min_noncelen, drbg->max_noncelen);
402 if (noncelen < drbg->min_noncelen || noncelen > drbg->max_noncelen) {
403 RANDerr(RAND_F_RAND_DRBG_INSTANTIATE, RAND_R_ERROR_RETRIEVING_NONCE);
408 if (!drbg->meth->instantiate(drbg, entropy, entropylen,
409 nonce, noncelen, pers, perslen)) {
410 RANDerr(RAND_F_RAND_DRBG_INSTANTIATE, RAND_R_ERROR_INSTANTIATING_DRBG);
414 drbg->state = DRBG_READY;
415 drbg->reseed_gen_counter = 1;
416 drbg->reseed_time = time(NULL);
417 tsan_store(&drbg->reseed_prop_counter, drbg->reseed_next_counter);
420 if (entropy != NULL && drbg->cleanup_entropy != NULL)
421 drbg->cleanup_entropy(drbg, entropy, entropylen);
422 if (nonce != NULL && drbg->cleanup_nonce != NULL)
423 drbg->cleanup_nonce(drbg, nonce, noncelen);
424 if (drbg->state == DRBG_READY)
430 * Uninstantiate |drbg|. Must be instantiated before it can be used.
432 * Requires that drbg->lock is already locked for write, if non-null.
434 * Returns 1 on success, 0 on failure.
436 int RAND_DRBG_uninstantiate(RAND_DRBG *drbg)
438 int index = -1, type, flags;
439 if (drbg->meth == NULL) {
440 drbg->state = DRBG_ERROR;
441 RANDerr(RAND_F_RAND_DRBG_UNINSTANTIATE,
442 RAND_R_NO_DRBG_IMPLEMENTATION_SELECTED);
446 /* Clear the entire drbg->ctr struct, then reset some important
447 * members of the drbg->ctr struct (e.g. keysize, df_ks) to their
450 drbg->meth->uninstantiate(drbg);
452 /* The reset uses the default values for type and flags */
453 if (drbg->flags & RAND_DRBG_FLAG_MASTER)
454 index = RAND_DRBG_TYPE_MASTER;
455 else if (drbg->flags & RAND_DRBG_FLAG_PRIVATE)
456 index = RAND_DRBG_TYPE_PRIVATE;
457 else if (drbg->flags & RAND_DRBG_FLAG_PUBLIC)
458 index = RAND_DRBG_TYPE_PUBLIC;
461 flags = rand_drbg_flags[index];
462 type = rand_drbg_type[index];
467 return RAND_DRBG_set(drbg, type, flags);
471 * Reseed |drbg|, mixing in the specified data
473 * Requires that drbg->lock is already locked for write, if non-null.
475 * Returns 1 on success, 0 on failure.
477 int RAND_DRBG_reseed(RAND_DRBG *drbg,
478 const unsigned char *adin, size_t adinlen,
479 int prediction_resistance)
481 unsigned char *entropy = NULL;
482 size_t entropylen = 0;
484 if (drbg->state == DRBG_ERROR) {
485 RANDerr(RAND_F_RAND_DRBG_RESEED, RAND_R_IN_ERROR_STATE);
488 if (drbg->state == DRBG_UNINITIALISED) {
489 RANDerr(RAND_F_RAND_DRBG_RESEED, RAND_R_NOT_INSTANTIATED);
495 } else if (adinlen > drbg->max_adinlen) {
496 RANDerr(RAND_F_RAND_DRBG_RESEED, RAND_R_ADDITIONAL_INPUT_TOO_LONG);
500 drbg->state = DRBG_ERROR;
502 drbg->reseed_next_counter = tsan_load(&drbg->reseed_prop_counter);
503 if (drbg->reseed_next_counter) {
504 drbg->reseed_next_counter++;
505 if(!drbg->reseed_next_counter)
506 drbg->reseed_next_counter = 1;
509 if (drbg->get_entropy != NULL)
510 entropylen = drbg->get_entropy(drbg, &entropy, drbg->strength,
511 drbg->min_entropylen,
512 drbg->max_entropylen,
513 prediction_resistance);
514 if (entropylen < drbg->min_entropylen
515 || entropylen > drbg->max_entropylen) {
516 RANDerr(RAND_F_RAND_DRBG_RESEED, RAND_R_ERROR_RETRIEVING_ENTROPY);
520 if (!drbg->meth->reseed(drbg, entropy, entropylen, adin, adinlen))
523 drbg->state = DRBG_READY;
524 drbg->reseed_gen_counter = 1;
525 drbg->reseed_time = time(NULL);
526 tsan_store(&drbg->reseed_prop_counter, drbg->reseed_next_counter);
529 if (entropy != NULL && drbg->cleanup_entropy != NULL)
530 drbg->cleanup_entropy(drbg, entropy, entropylen);
531 if (drbg->state == DRBG_READY)
537 * Restart |drbg|, using the specified entropy or additional input
539 * Tries its best to get the drbg instantiated by all means,
540 * regardless of its current state.
542 * Optionally, a |buffer| of |len| random bytes can be passed,
543 * which is assumed to contain at least |entropy| bits of entropy.
545 * If |entropy| > 0, the buffer content is used as entropy input.
547 * If |entropy| == 0, the buffer content is used as additional input
549 * Returns 1 on success, 0 on failure.
551 * This function is used internally only.
553 int rand_drbg_restart(RAND_DRBG *drbg,
554 const unsigned char *buffer, size_t len, size_t entropy)
557 const unsigned char *adin = NULL;
560 if (drbg->seed_pool != NULL) {
561 RANDerr(RAND_F_RAND_DRBG_RESTART, ERR_R_INTERNAL_ERROR);
562 drbg->state = DRBG_ERROR;
563 rand_pool_free(drbg->seed_pool);
564 drbg->seed_pool = NULL;
568 if (buffer != NULL) {
570 if (drbg->max_entropylen < len) {
571 RANDerr(RAND_F_RAND_DRBG_RESTART,
572 RAND_R_ENTROPY_INPUT_TOO_LONG);
573 drbg->state = DRBG_ERROR;
577 if (entropy > 8 * len) {
578 RANDerr(RAND_F_RAND_DRBG_RESTART, RAND_R_ENTROPY_OUT_OF_RANGE);
579 drbg->state = DRBG_ERROR;
583 /* will be picked up by the rand_drbg_get_entropy() callback */
584 drbg->seed_pool = rand_pool_attach(buffer, len, entropy);
585 if (drbg->seed_pool == NULL)
588 if (drbg->max_adinlen < len) {
589 RANDerr(RAND_F_RAND_DRBG_RESTART,
590 RAND_R_ADDITIONAL_INPUT_TOO_LONG);
591 drbg->state = DRBG_ERROR;
599 /* repair error state */
600 if (drbg->state == DRBG_ERROR)
601 RAND_DRBG_uninstantiate(drbg);
603 /* repair uninitialized state */
604 if (drbg->state == DRBG_UNINITIALISED) {
605 /* reinstantiate drbg */
606 RAND_DRBG_instantiate(drbg,
607 (const unsigned char *) ossl_pers_string,
608 sizeof(ossl_pers_string) - 1);
609 /* already reseeded. prevent second reseeding below */
610 reseeded = (drbg->state == DRBG_READY);
613 /* refresh current state if entropy or additional input has been provided */
614 if (drbg->state == DRBG_READY) {
617 * mix in additional input without reseeding
619 * Similar to RAND_DRBG_reseed(), but the provided additional
620 * data |adin| is mixed into the current state without pulling
621 * entropy from the trusted entropy source using get_entropy().
622 * This is not a reseeding in the strict sense of NIST SP 800-90A.
624 drbg->meth->reseed(drbg, adin, adinlen, NULL, 0);
625 } else if (reseeded == 0) {
626 /* do a full reseeding if it has not been done yet above */
627 RAND_DRBG_reseed(drbg, NULL, 0, 0);
631 rand_pool_free(drbg->seed_pool);
632 drbg->seed_pool = NULL;
634 return drbg->state == DRBG_READY;
638 * Generate |outlen| bytes into the buffer at |out|. Reseed if we need
639 * to or if |prediction_resistance| is set. Additional input can be
640 * sent in |adin| and |adinlen|.
642 * Requires that drbg->lock is already locked for write, if non-null.
644 * Returns 1 on success, 0 on failure.
647 int RAND_DRBG_generate(RAND_DRBG *drbg, unsigned char *out, size_t outlen,
648 int prediction_resistance,
649 const unsigned char *adin, size_t adinlen)
651 int reseed_required = 0;
653 if (drbg->state != DRBG_READY) {
654 /* try to recover from previous errors */
655 rand_drbg_restart(drbg, NULL, 0, 0);
657 if (drbg->state == DRBG_ERROR) {
658 RANDerr(RAND_F_RAND_DRBG_GENERATE, RAND_R_IN_ERROR_STATE);
661 if (drbg->state == DRBG_UNINITIALISED) {
662 RANDerr(RAND_F_RAND_DRBG_GENERATE, RAND_R_NOT_INSTANTIATED);
667 if (outlen > drbg->max_request) {
668 RANDerr(RAND_F_RAND_DRBG_GENERATE, RAND_R_REQUEST_TOO_LARGE_FOR_DRBG);
671 if (adinlen > drbg->max_adinlen) {
672 RANDerr(RAND_F_RAND_DRBG_GENERATE, RAND_R_ADDITIONAL_INPUT_TOO_LONG);
676 if (drbg->fork_count != rand_fork_count) {
677 drbg->fork_count = rand_fork_count;
681 if (drbg->reseed_interval > 0) {
682 if (drbg->reseed_gen_counter > drbg->reseed_interval)
685 if (drbg->reseed_time_interval > 0) {
686 time_t now = time(NULL);
687 if (now < drbg->reseed_time
688 || now - drbg->reseed_time >= drbg->reseed_time_interval)
691 if (drbg->parent != NULL) {
692 unsigned int reseed_counter = tsan_load(&drbg->reseed_prop_counter);
693 if (reseed_counter > 0
694 && tsan_load(&drbg->parent->reseed_prop_counter)
699 if (reseed_required || prediction_resistance) {
700 if (!RAND_DRBG_reseed(drbg, adin, adinlen, prediction_resistance)) {
701 RANDerr(RAND_F_RAND_DRBG_GENERATE, RAND_R_RESEED_ERROR);
708 if (!drbg->meth->generate(drbg, out, outlen, adin, adinlen)) {
709 drbg->state = DRBG_ERROR;
710 RANDerr(RAND_F_RAND_DRBG_GENERATE, RAND_R_GENERATE_ERROR);
714 drbg->reseed_gen_counter++;
720 * Generates |outlen| random bytes and stores them in |out|. It will
721 * using the given |drbg| to generate the bytes.
723 * Requires that drbg->lock is already locked for write, if non-null.
725 * Returns 1 on success 0 on failure.
727 int RAND_DRBG_bytes(RAND_DRBG *drbg, unsigned char *out, size_t outlen)
729 unsigned char *additional = NULL;
730 size_t additional_len;
734 if (drbg->adin_pool == NULL) {
737 drbg->adin_pool = rand_pool_new(0, 0, drbg->max_adinlen);
738 if (drbg->adin_pool == NULL)
742 additional_len = rand_drbg_get_additional_data(drbg->adin_pool,
745 for ( ; outlen > 0; outlen -= chunk, out += chunk) {
747 if (chunk > drbg->max_request)
748 chunk = drbg->max_request;
749 ret = RAND_DRBG_generate(drbg, out, chunk, 0, additional, additional_len);
756 if (additional != NULL)
757 rand_drbg_cleanup_additional_data(drbg->adin_pool, additional);
763 * Set the RAND_DRBG callbacks for obtaining entropy and nonce.
765 * Setting the callbacks is allowed only if the drbg has not been
766 * initialized yet. Otherwise, the operation will fail.
768 * Returns 1 on success, 0 on failure.
770 int RAND_DRBG_set_callbacks(RAND_DRBG *drbg,
771 RAND_DRBG_get_entropy_fn get_entropy,
772 RAND_DRBG_cleanup_entropy_fn cleanup_entropy,
773 RAND_DRBG_get_nonce_fn get_nonce,
774 RAND_DRBG_cleanup_nonce_fn cleanup_nonce)
776 if (drbg->state != DRBG_UNINITIALISED
777 || drbg->parent != NULL)
779 drbg->get_entropy = get_entropy;
780 drbg->cleanup_entropy = cleanup_entropy;
781 drbg->get_nonce = get_nonce;
782 drbg->cleanup_nonce = cleanup_nonce;
787 * Set the reseed interval.
789 * The drbg will reseed automatically whenever the number of generate
790 * requests exceeds the given reseed interval. If the reseed interval
791 * is 0, then this feature is disabled.
793 * Returns 1 on success, 0 on failure.
795 int RAND_DRBG_set_reseed_interval(RAND_DRBG *drbg, unsigned int interval)
797 if (interval > MAX_RESEED_INTERVAL)
799 drbg->reseed_interval = interval;
804 * Set the reseed time interval.
806 * The drbg will reseed automatically whenever the time elapsed since
807 * the last reseeding exceeds the given reseed time interval. For safety,
808 * a reseeding will also occur if the clock has been reset to a smaller
811 * Returns 1 on success, 0 on failure.
813 int RAND_DRBG_set_reseed_time_interval(RAND_DRBG *drbg, time_t interval)
815 if (interval > MAX_RESEED_TIME_INTERVAL)
817 drbg->reseed_time_interval = interval;
822 * Set the default values for reseed (time) intervals of new DRBG instances
824 * The default values can be set independently for master DRBG instances
825 * (without a parent) and slave DRBG instances (with parent).
827 * Returns 1 on success, 0 on failure.
830 int RAND_DRBG_set_reseed_defaults(
831 unsigned int _master_reseed_interval,
832 unsigned int _slave_reseed_interval,
833 time_t _master_reseed_time_interval,
834 time_t _slave_reseed_time_interval
837 if (_master_reseed_interval > MAX_RESEED_INTERVAL
838 || _slave_reseed_interval > MAX_RESEED_INTERVAL)
841 if (_master_reseed_time_interval > MAX_RESEED_TIME_INTERVAL
842 || _slave_reseed_time_interval > MAX_RESEED_TIME_INTERVAL)
845 master_reseed_interval = _master_reseed_interval;
846 slave_reseed_interval = _slave_reseed_interval;
848 master_reseed_time_interval = _master_reseed_time_interval;
849 slave_reseed_time_interval = _slave_reseed_time_interval;
855 * Locks the given drbg. Locking a drbg which does not have locking
856 * enabled is considered a successful no-op.
858 * Returns 1 on success, 0 on failure.
860 int rand_drbg_lock(RAND_DRBG *drbg)
862 if (drbg->lock != NULL)
863 return CRYPTO_THREAD_write_lock(drbg->lock);
869 * Unlocks the given drbg. Unlocking a drbg which does not have locking
870 * enabled is considered a successful no-op.
872 * Returns 1 on success, 0 on failure.
874 int rand_drbg_unlock(RAND_DRBG *drbg)
876 if (drbg->lock != NULL)
877 return CRYPTO_THREAD_unlock(drbg->lock);
883 * Enables locking for the given drbg
885 * Locking can only be enabled if the random generator
886 * is in the uninitialized state.
888 * Returns 1 on success, 0 on failure.
890 int rand_drbg_enable_locking(RAND_DRBG *drbg)
892 if (drbg->state != DRBG_UNINITIALISED) {
893 RANDerr(RAND_F_RAND_DRBG_ENABLE_LOCKING,
894 RAND_R_DRBG_ALREADY_INITIALIZED);
898 if (drbg->lock == NULL) {
899 if (drbg->parent != NULL && drbg->parent->lock == NULL) {
900 RANDerr(RAND_F_RAND_DRBG_ENABLE_LOCKING,
901 RAND_R_PARENT_LOCKING_NOT_ENABLED);
905 drbg->lock = CRYPTO_THREAD_lock_new();
906 if (drbg->lock == NULL) {
907 RANDerr(RAND_F_RAND_DRBG_ENABLE_LOCKING,
908 RAND_R_FAILED_TO_CREATE_LOCK);
917 * Get and set the EXDATA
919 int RAND_DRBG_set_ex_data(RAND_DRBG *drbg, int idx, void *arg)
921 return CRYPTO_set_ex_data(&drbg->ex_data, idx, arg);
924 void *RAND_DRBG_get_ex_data(const RAND_DRBG *drbg, int idx)
926 return CRYPTO_get_ex_data(&drbg->ex_data, idx);
931 * The following functions provide a RAND_METHOD that works on the
932 * global DRBG. They lock.
936 * Allocates a new global DRBG on the secure heap (if enabled) and
937 * initializes it with default settings.
939 * Returns a pointer to the new DRBG instance on success, NULL on failure.
941 static RAND_DRBG *drbg_setup(RAND_DRBG *parent, int drbg_type)
945 drbg = RAND_DRBG_secure_new(rand_drbg_type[drbg_type],
946 rand_drbg_flags[drbg_type], parent);
950 /* Only the master DRBG needs to have a lock */
951 if (parent == NULL && rand_drbg_enable_locking(drbg) == 0)
954 /* enable seed propagation */
955 tsan_store(&drbg->reseed_prop_counter, 1);
958 * Ignore instantiation error to support just-in-time instantiation.
960 * The state of the drbg will be checked in RAND_DRBG_generate() and
961 * an automatic recovery is attempted.
963 (void)RAND_DRBG_instantiate(drbg,
964 (const unsigned char *) ossl_pers_string,
965 sizeof(ossl_pers_string) - 1);
969 RAND_DRBG_free(drbg);
974 * Initialize the global DRBGs on first use.
975 * Returns 1 on success, 0 on failure.
977 DEFINE_RUN_ONCE_STATIC(do_rand_drbg_init)
980 * ensure that libcrypto is initialized, otherwise the
981 * DRBG locks are not cleaned up properly
983 if (!OPENSSL_init_crypto(0, NULL))
986 if (!CRYPTO_THREAD_init_local(&private_drbg, NULL))
989 if (!CRYPTO_THREAD_init_local(&public_drbg, NULL))
992 master_drbg = drbg_setup(NULL, RAND_DRBG_TYPE_MASTER);
993 if (master_drbg == NULL)
999 CRYPTO_THREAD_cleanup_local(&public_drbg);
1001 CRYPTO_THREAD_cleanup_local(&private_drbg);
1005 /* Clean up the global DRBGs before exit */
1006 void rand_drbg_cleanup_int(void)
1008 if (master_drbg != NULL) {
1009 RAND_DRBG_free(master_drbg);
1012 CRYPTO_THREAD_cleanup_local(&private_drbg);
1013 CRYPTO_THREAD_cleanup_local(&public_drbg);
1017 void drbg_delete_thread_state(void)
1021 drbg = CRYPTO_THREAD_get_local(&public_drbg);
1022 CRYPTO_THREAD_set_local(&public_drbg, NULL);
1023 RAND_DRBG_free(drbg);
1025 drbg = CRYPTO_THREAD_get_local(&private_drbg);
1026 CRYPTO_THREAD_set_local(&private_drbg, NULL);
1027 RAND_DRBG_free(drbg);
1030 /* Implements the default OpenSSL RAND_bytes() method */
1031 static int drbg_bytes(unsigned char *out, int count)
1034 RAND_DRBG *drbg = RAND_DRBG_get0_public();
1039 ret = RAND_DRBG_bytes(drbg, out, count);
1045 * Calculates the minimum length of a full entropy buffer
1046 * which is necessary to seed (i.e. instantiate) the DRBG
1049 size_t rand_drbg_seedlen(RAND_DRBG *drbg)
1052 * If no os entropy source is available then RAND_seed(buffer, bufsize)
1053 * is expected to succeed if and only if the buffer length satisfies
1054 * the following requirements, which follow from the calculations
1055 * in RAND_DRBG_instantiate().
1057 size_t min_entropy = drbg->strength;
1058 size_t min_entropylen = drbg->min_entropylen;
1061 * Extra entropy for the random nonce in the absence of a
1062 * get_nonce callback, see comment in RAND_DRBG_instantiate().
1064 if (drbg->min_noncelen > 0 && drbg->get_nonce == NULL) {
1065 min_entropy += drbg->strength / 2;
1066 min_entropylen += drbg->min_noncelen;
1070 * Convert entropy requirement from bits to bytes
1071 * (dividing by 8 without rounding upwards, because
1072 * all entropy requirements are divisible by 8).
1076 /* Return a value that satisfies both requirements */
1077 return min_entropy > min_entropylen ? min_entropy : min_entropylen;
1080 /* Implements the default OpenSSL RAND_add() method */
1081 static int drbg_add(const void *buf, int num, double randomness)
1084 RAND_DRBG *drbg = RAND_DRBG_get0_master();
1091 if (num < 0 || randomness < 0.0)
1094 rand_drbg_lock(drbg);
1095 seedlen = rand_drbg_seedlen(drbg);
1097 buflen = (size_t)num;
1099 if (buflen < seedlen || randomness < (double) seedlen) {
1100 #if defined(OPENSSL_RAND_SEED_NONE)
1102 * If no os entropy source is available, a reseeding will fail
1103 * inevitably. So we use a trick to mix the buffer contents into
1104 * the DRBG state without forcing a reseeding: we generate a
1105 * dummy random byte, using the buffer content as additional data.
1106 * Note: This won't work with RAND_DRBG_FLAG_CTR_NO_DF.
1108 unsigned char dummy[1];
1110 ret = RAND_DRBG_generate(drbg, dummy, sizeof(dummy), 0, buf, buflen);
1111 rand_drbg_unlock(drbg);
1115 * If an os entropy source is avaible then we declare the buffer content
1116 * as additional data by setting randomness to zero and trigger a regular
1124 if (randomness > (double)seedlen) {
1126 * The purpose of this check is to bound |randomness| by a
1127 * relatively small value in order to prevent an integer
1128 * overflow when multiplying by 8 in the rand_drbg_restart()
1129 * call below. Note that randomness is measured in bytes,
1130 * not bits, so this value corresponds to eight times the
1131 * security strength.
1133 randomness = (double)seedlen;
1136 ret = rand_drbg_restart(drbg, buf, buflen, (size_t)(8 * randomness));
1137 rand_drbg_unlock(drbg);
1142 /* Implements the default OpenSSL RAND_seed() method */
1143 static int drbg_seed(const void *buf, int num)
1145 return drbg_add(buf, num, num);
1148 /* Implements the default OpenSSL RAND_status() method */
1149 static int drbg_status(void)
1152 RAND_DRBG *drbg = RAND_DRBG_get0_master();
1157 rand_drbg_lock(drbg);
1158 ret = drbg->state == DRBG_READY ? 1 : 0;
1159 rand_drbg_unlock(drbg);
1164 * Get the master DRBG.
1165 * Returns pointer to the DRBG on success, NULL on failure.
1168 RAND_DRBG *RAND_DRBG_get0_master(void)
1170 if (!RUN_ONCE(&rand_drbg_init, do_rand_drbg_init))
1177 * Get the public DRBG.
1178 * Returns pointer to the DRBG on success, NULL on failure.
1180 RAND_DRBG *RAND_DRBG_get0_public(void)
1184 if (!RUN_ONCE(&rand_drbg_init, do_rand_drbg_init))
1187 drbg = CRYPTO_THREAD_get_local(&public_drbg);
1189 if (!ossl_init_thread_start(OPENSSL_INIT_THREAD_RAND))
1191 drbg = drbg_setup(master_drbg, RAND_DRBG_TYPE_PUBLIC);
1192 CRYPTO_THREAD_set_local(&public_drbg, drbg);
1198 * Get the private DRBG.
1199 * Returns pointer to the DRBG on success, NULL on failure.
1201 RAND_DRBG *RAND_DRBG_get0_private(void)
1205 if (!RUN_ONCE(&rand_drbg_init, do_rand_drbg_init))
1208 drbg = CRYPTO_THREAD_get_local(&private_drbg);
1210 if (!ossl_init_thread_start(OPENSSL_INIT_THREAD_RAND))
1212 drbg = drbg_setup(master_drbg, RAND_DRBG_TYPE_PRIVATE);
1213 CRYPTO_THREAD_set_local(&private_drbg, drbg);
1218 RAND_METHOD rand_meth = {
1227 RAND_METHOD *RAND_OpenSSL(void)