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 (type != drbg->type && drbg->type != 0 && drbg->meth != NULL) {
162 drbg->meth->uninstantiate(drbg);
165 drbg->state = DRBG_UNINITIALISED;
170 /* Uninitialized; that's okay. */
172 } else if (is_ctr(type)) {
173 ret = drbg_ctr_init(drbg);
174 } else if (is_digest(type)) {
175 if (flags & RAND_DRBG_FLAG_HMAC)
176 ret = drbg_hmac_init(drbg);
178 ret = drbg_hash_init(drbg);
180 RANDerr(RAND_F_RAND_DRBG_SET, RAND_R_UNSUPPORTED_DRBG_TYPE);
185 RANDerr(RAND_F_RAND_DRBG_SET, RAND_R_ERROR_INITIALISING_DRBG);
190 * Set/initialize default |type| and |flag| for new drbg instances.
192 * Returns 1 on success, 0 on failure.
194 int RAND_DRBG_set_defaults(int type, unsigned int flags)
197 if (!(is_digest(type) || is_ctr(type))) {
198 RANDerr(RAND_F_RAND_DRBG_SET_DEFAULTS, RAND_R_UNSUPPORTED_DRBG_TYPE);
202 if ((flags & ~rand_drbg_used_flags) != 0) {
203 RANDerr(RAND_F_RAND_DRBG_SET_DEFAULTS, RAND_R_UNSUPPORTED_DRBG_FLAGS);
207 all = ((flags & RAND_DRBG_TYPE_FLAGS) == 0);
208 if (all || (flags & RAND_DRBG_FLAG_MASTER) != 0) {
209 rand_drbg_type[RAND_DRBG_TYPE_MASTER] = type;
210 rand_drbg_flags[RAND_DRBG_TYPE_MASTER] = flags | RAND_DRBG_FLAG_MASTER;
212 if (all || (flags & RAND_DRBG_FLAG_PUBLIC) != 0) {
213 rand_drbg_type[RAND_DRBG_TYPE_PUBLIC] = type;
214 rand_drbg_flags[RAND_DRBG_TYPE_PUBLIC] = flags | RAND_DRBG_FLAG_PUBLIC;
216 if (all || (flags & RAND_DRBG_FLAG_PRIVATE) != 0) {
217 rand_drbg_type[RAND_DRBG_TYPE_PRIVATE] = type;
218 rand_drbg_flags[RAND_DRBG_TYPE_PRIVATE] = flags | RAND_DRBG_FLAG_PRIVATE;
225 * Allocate memory and initialize a new DRBG. The DRBG is allocated on
226 * the secure heap if |secure| is nonzero and the secure heap is enabled.
227 * The |parent|, if not NULL, will be used as random source for reseeding.
229 * Returns a pointer to the new DRBG instance on success, NULL on failure.
231 static RAND_DRBG *rand_drbg_new(int secure,
236 RAND_DRBG *drbg = secure ?
237 OPENSSL_secure_zalloc(sizeof(*drbg)) : OPENSSL_zalloc(sizeof(*drbg));
240 RANDerr(RAND_F_RAND_DRBG_NEW, ERR_R_MALLOC_FAILURE);
244 drbg->secure = secure && CRYPTO_secure_allocated(drbg);
245 drbg->fork_count = rand_fork_count;
246 drbg->parent = parent;
248 if (parent == NULL) {
249 drbg->get_entropy = rand_drbg_get_entropy;
250 drbg->cleanup_entropy = rand_drbg_cleanup_entropy;
251 #ifndef RAND_DRBG_GET_RANDOM_NONCE
252 drbg->get_nonce = rand_drbg_get_nonce;
253 drbg->cleanup_nonce = rand_drbg_cleanup_nonce;
256 drbg->reseed_interval = master_reseed_interval;
257 drbg->reseed_time_interval = master_reseed_time_interval;
259 drbg->get_entropy = rand_drbg_get_entropy;
260 drbg->cleanup_entropy = rand_drbg_cleanup_entropy;
262 * Do not provide nonce callbacks, the child DRBGs will
263 * obtain their nonce using random bits from the parent.
266 drbg->reseed_interval = slave_reseed_interval;
267 drbg->reseed_time_interval = slave_reseed_time_interval;
270 if (RAND_DRBG_set(drbg, type, flags) == 0)
273 if (parent != NULL) {
274 rand_drbg_lock(parent);
275 if (drbg->strength > parent->strength) {
277 * We currently don't support the algorithm from NIST SP 800-90C
278 * 10.1.2 to use a weaker DRBG as source
280 rand_drbg_unlock(parent);
281 RANDerr(RAND_F_RAND_DRBG_NEW, RAND_R_PARENT_STRENGTH_TOO_WEAK);
284 rand_drbg_unlock(parent);
291 OPENSSL_secure_free(drbg);
298 RAND_DRBG *RAND_DRBG_new(int type, unsigned int flags, RAND_DRBG *parent)
300 return rand_drbg_new(0, type, flags, parent);
303 RAND_DRBG *RAND_DRBG_secure_new(int type, unsigned int flags, RAND_DRBG *parent)
305 return rand_drbg_new(1, type, flags, parent);
309 * Uninstantiate |drbg| and free all memory.
311 void RAND_DRBG_free(RAND_DRBG *drbg)
316 if (drbg->meth != NULL)
317 drbg->meth->uninstantiate(drbg);
318 CRYPTO_THREAD_lock_free(drbg->lock);
319 CRYPTO_free_ex_data(CRYPTO_EX_INDEX_DRBG, drbg, &drbg->ex_data);
322 OPENSSL_secure_clear_free(drbg, sizeof(*drbg));
324 OPENSSL_clear_free(drbg, sizeof(*drbg));
328 * Instantiate |drbg|, after it has been initialized. Use |pers| and
329 * |perslen| as prediction-resistance input.
331 * Requires that drbg->lock is already locked for write, if non-null.
333 * Returns 1 on success, 0 on failure.
335 int RAND_DRBG_instantiate(RAND_DRBG *drbg,
336 const unsigned char *pers, size_t perslen)
338 unsigned char *nonce = NULL, *entropy = NULL;
339 size_t noncelen = 0, entropylen = 0;
340 size_t min_entropy = drbg->strength;
341 size_t min_entropylen = drbg->min_entropylen;
342 size_t max_entropylen = drbg->max_entropylen;
344 if (perslen > drbg->max_perslen) {
345 RANDerr(RAND_F_RAND_DRBG_INSTANTIATE,
346 RAND_R_PERSONALISATION_STRING_TOO_LONG);
350 if (drbg->meth == NULL) {
351 RANDerr(RAND_F_RAND_DRBG_INSTANTIATE,
352 RAND_R_NO_DRBG_IMPLEMENTATION_SELECTED);
356 if (drbg->state != DRBG_UNINITIALISED) {
357 RANDerr(RAND_F_RAND_DRBG_INSTANTIATE,
358 drbg->state == DRBG_ERROR ? RAND_R_IN_ERROR_STATE
359 : RAND_R_ALREADY_INSTANTIATED);
363 drbg->state = DRBG_ERROR;
366 * NIST SP800-90Ar1 section 9.1 says you can combine getting the entropy
367 * and nonce in 1 call by increasing the entropy with 50% and increasing
368 * the minimum length to accomadate the length of the nonce.
369 * We do this in case a nonce is require and get_nonce is NULL.
371 if (drbg->min_noncelen > 0 && drbg->get_nonce == NULL) {
372 min_entropy += drbg->strength / 2;
373 min_entropylen += drbg->min_noncelen;
374 max_entropylen += drbg->max_noncelen;
377 drbg->reseed_next_counter = tsan_load(&drbg->reseed_prop_counter);
378 if (drbg->reseed_next_counter) {
379 drbg->reseed_next_counter++;
380 if(!drbg->reseed_next_counter)
381 drbg->reseed_next_counter = 1;
384 if (drbg->get_entropy != NULL)
385 entropylen = drbg->get_entropy(drbg, &entropy, min_entropy,
386 min_entropylen, max_entropylen, 0);
387 if (entropylen < min_entropylen
388 || entropylen > max_entropylen) {
389 RANDerr(RAND_F_RAND_DRBG_INSTANTIATE, RAND_R_ERROR_RETRIEVING_ENTROPY);
393 if (drbg->min_noncelen > 0 && drbg->get_nonce != NULL) {
394 noncelen = drbg->get_nonce(drbg, &nonce, drbg->strength / 2,
395 drbg->min_noncelen, drbg->max_noncelen);
396 if (noncelen < drbg->min_noncelen || noncelen > drbg->max_noncelen) {
397 RANDerr(RAND_F_RAND_DRBG_INSTANTIATE, RAND_R_ERROR_RETRIEVING_NONCE);
402 if (!drbg->meth->instantiate(drbg, entropy, entropylen,
403 nonce, noncelen, pers, perslen)) {
404 RANDerr(RAND_F_RAND_DRBG_INSTANTIATE, RAND_R_ERROR_INSTANTIATING_DRBG);
408 drbg->state = DRBG_READY;
409 drbg->reseed_gen_counter = 1;
410 drbg->reseed_time = time(NULL);
411 tsan_store(&drbg->reseed_prop_counter, drbg->reseed_next_counter);
414 if (entropy != NULL && drbg->cleanup_entropy != NULL)
415 drbg->cleanup_entropy(drbg, entropy, entropylen);
416 if (nonce != NULL && drbg->cleanup_nonce != NULL)
417 drbg->cleanup_nonce(drbg, nonce, noncelen);
418 if (drbg->state == DRBG_READY)
424 * Uninstantiate |drbg|. Must be instantiated before it can be used.
426 * Requires that drbg->lock is already locked for write, if non-null.
428 * Returns 1 on success, 0 on failure.
430 int RAND_DRBG_uninstantiate(RAND_DRBG *drbg)
432 int index = -1, type, flags;
433 if (drbg->meth == NULL) {
434 RANDerr(RAND_F_RAND_DRBG_UNINSTANTIATE,
435 RAND_R_NO_DRBG_IMPLEMENTATION_SELECTED);
439 /* Clear the entire drbg->ctr struct, then reset some important
440 * members of the drbg->ctr struct (e.g. keysize, df_ks) to their
443 drbg->meth->uninstantiate(drbg);
445 /* The reset uses the default values for type and flags */
446 if (drbg->flags & RAND_DRBG_FLAG_MASTER)
447 index = RAND_DRBG_TYPE_MASTER;
448 else if (drbg->flags & RAND_DRBG_FLAG_PRIVATE)
449 index = RAND_DRBG_TYPE_PRIVATE;
450 else if (drbg->flags & RAND_DRBG_FLAG_PUBLIC)
451 index = RAND_DRBG_TYPE_PUBLIC;
454 flags = rand_drbg_flags[index];
455 type = rand_drbg_type[index];
460 return RAND_DRBG_set(drbg, type, flags);
464 * Reseed |drbg|, mixing in the specified data
466 * Requires that drbg->lock is already locked for write, if non-null.
468 * Returns 1 on success, 0 on failure.
470 int RAND_DRBG_reseed(RAND_DRBG *drbg,
471 const unsigned char *adin, size_t adinlen,
472 int prediction_resistance)
474 unsigned char *entropy = NULL;
475 size_t entropylen = 0;
477 if (drbg->state == DRBG_ERROR) {
478 RANDerr(RAND_F_RAND_DRBG_RESEED, RAND_R_IN_ERROR_STATE);
481 if (drbg->state == DRBG_UNINITIALISED) {
482 RANDerr(RAND_F_RAND_DRBG_RESEED, RAND_R_NOT_INSTANTIATED);
488 } else if (adinlen > drbg->max_adinlen) {
489 RANDerr(RAND_F_RAND_DRBG_RESEED, RAND_R_ADDITIONAL_INPUT_TOO_LONG);
493 drbg->state = DRBG_ERROR;
495 drbg->reseed_next_counter = tsan_load(&drbg->reseed_prop_counter);
496 if (drbg->reseed_next_counter) {
497 drbg->reseed_next_counter++;
498 if(!drbg->reseed_next_counter)
499 drbg->reseed_next_counter = 1;
502 if (drbg->get_entropy != NULL)
503 entropylen = drbg->get_entropy(drbg, &entropy, drbg->strength,
504 drbg->min_entropylen,
505 drbg->max_entropylen,
506 prediction_resistance);
507 if (entropylen < drbg->min_entropylen
508 || entropylen > drbg->max_entropylen) {
509 RANDerr(RAND_F_RAND_DRBG_RESEED, RAND_R_ERROR_RETRIEVING_ENTROPY);
513 if (!drbg->meth->reseed(drbg, entropy, entropylen, adin, adinlen))
516 drbg->state = DRBG_READY;
517 drbg->reseed_gen_counter = 1;
518 drbg->reseed_time = time(NULL);
519 tsan_store(&drbg->reseed_prop_counter, drbg->reseed_next_counter);
522 if (entropy != NULL && drbg->cleanup_entropy != NULL)
523 drbg->cleanup_entropy(drbg, entropy, entropylen);
524 if (drbg->state == DRBG_READY)
530 * Restart |drbg|, using the specified entropy or additional input
532 * Tries its best to get the drbg instantiated by all means,
533 * regardless of its current state.
535 * Optionally, a |buffer| of |len| random bytes can be passed,
536 * which is assumed to contain at least |entropy| bits of entropy.
538 * If |entropy| > 0, the buffer content is used as entropy input.
540 * If |entropy| == 0, the buffer content is used as additional input
542 * Returns 1 on success, 0 on failure.
544 * This function is used internally only.
546 int rand_drbg_restart(RAND_DRBG *drbg,
547 const unsigned char *buffer, size_t len, size_t entropy)
550 const unsigned char *adin = NULL;
553 if (drbg->pool != NULL) {
554 RANDerr(RAND_F_RAND_DRBG_RESTART, ERR_R_INTERNAL_ERROR);
555 drbg->state = DRBG_ERROR;
556 rand_pool_free(drbg->pool);
561 if (buffer != NULL) {
563 if (drbg->max_entropylen < len) {
564 RANDerr(RAND_F_RAND_DRBG_RESTART,
565 RAND_R_ENTROPY_INPUT_TOO_LONG);
566 drbg->state = DRBG_ERROR;
570 if (entropy > 8 * len) {
571 RANDerr(RAND_F_RAND_DRBG_RESTART, RAND_R_ENTROPY_OUT_OF_RANGE);
572 drbg->state = DRBG_ERROR;
576 /* will be picked up by the rand_drbg_get_entropy() callback */
577 drbg->pool = rand_pool_attach(buffer, len, entropy);
578 if (drbg->pool == NULL)
581 if (drbg->max_adinlen < len) {
582 RANDerr(RAND_F_RAND_DRBG_RESTART,
583 RAND_R_ADDITIONAL_INPUT_TOO_LONG);
584 drbg->state = DRBG_ERROR;
592 /* repair error state */
593 if (drbg->state == DRBG_ERROR)
594 RAND_DRBG_uninstantiate(drbg);
596 /* repair uninitialized state */
597 if (drbg->state == DRBG_UNINITIALISED) {
598 /* reinstantiate drbg */
599 RAND_DRBG_instantiate(drbg,
600 (const unsigned char *) ossl_pers_string,
601 sizeof(ossl_pers_string) - 1);
602 /* already reseeded. prevent second reseeding below */
603 reseeded = (drbg->state == DRBG_READY);
606 /* refresh current state if entropy or additional input has been provided */
607 if (drbg->state == DRBG_READY) {
610 * mix in additional input without reseeding
612 * Similar to RAND_DRBG_reseed(), but the provided additional
613 * data |adin| is mixed into the current state without pulling
614 * entropy from the trusted entropy source using get_entropy().
615 * This is not a reseeding in the strict sense of NIST SP 800-90A.
617 drbg->meth->reseed(drbg, adin, adinlen, NULL, 0);
618 } else if (reseeded == 0) {
619 /* do a full reseeding if it has not been done yet above */
620 RAND_DRBG_reseed(drbg, NULL, 0, 0);
624 rand_pool_free(drbg->pool);
627 return drbg->state == DRBG_READY;
631 * Generate |outlen| bytes into the buffer at |out|. Reseed if we need
632 * to or if |prediction_resistance| is set. Additional input can be
633 * sent in |adin| and |adinlen|.
635 * Requires that drbg->lock is already locked for write, if non-null.
637 * Returns 1 on success, 0 on failure.
640 int RAND_DRBG_generate(RAND_DRBG *drbg, unsigned char *out, size_t outlen,
641 int prediction_resistance,
642 const unsigned char *adin, size_t adinlen)
644 int reseed_required = 0;
646 if (drbg->state != DRBG_READY) {
647 /* try to recover from previous errors */
648 rand_drbg_restart(drbg, NULL, 0, 0);
650 if (drbg->state == DRBG_ERROR) {
651 RANDerr(RAND_F_RAND_DRBG_GENERATE, RAND_R_IN_ERROR_STATE);
654 if (drbg->state == DRBG_UNINITIALISED) {
655 RANDerr(RAND_F_RAND_DRBG_GENERATE, RAND_R_NOT_INSTANTIATED);
660 if (outlen > drbg->max_request) {
661 RANDerr(RAND_F_RAND_DRBG_GENERATE, RAND_R_REQUEST_TOO_LARGE_FOR_DRBG);
664 if (adinlen > drbg->max_adinlen) {
665 RANDerr(RAND_F_RAND_DRBG_GENERATE, RAND_R_ADDITIONAL_INPUT_TOO_LONG);
669 if (drbg->fork_count != rand_fork_count) {
670 drbg->fork_count = rand_fork_count;
674 if (drbg->reseed_interval > 0) {
675 if (drbg->reseed_gen_counter > drbg->reseed_interval)
678 if (drbg->reseed_time_interval > 0) {
679 time_t now = time(NULL);
680 if (now < drbg->reseed_time
681 || now - drbg->reseed_time >= drbg->reseed_time_interval)
684 if (drbg->parent != NULL) {
685 unsigned int reseed_counter = tsan_load(&drbg->reseed_prop_counter);
686 if (reseed_counter > 0
687 && tsan_load(&drbg->parent->reseed_prop_counter)
692 if (reseed_required || prediction_resistance) {
693 if (!RAND_DRBG_reseed(drbg, adin, adinlen, prediction_resistance)) {
694 RANDerr(RAND_F_RAND_DRBG_GENERATE, RAND_R_RESEED_ERROR);
701 if (!drbg->meth->generate(drbg, out, outlen, adin, adinlen)) {
702 drbg->state = DRBG_ERROR;
703 RANDerr(RAND_F_RAND_DRBG_GENERATE, RAND_R_GENERATE_ERROR);
707 drbg->reseed_gen_counter++;
713 * Generates |outlen| random bytes and stores them in |out|. It will
714 * using the given |drbg| to generate the bytes.
716 * Requires that drbg->lock is already locked for write, if non-null.
718 * Returns 1 on success 0 on failure.
720 int RAND_DRBG_bytes(RAND_DRBG *drbg, unsigned char *out, size_t outlen)
722 unsigned char *additional = NULL;
723 size_t additional_len;
727 additional_len = rand_drbg_get_additional_data(&additional, drbg->max_adinlen);
729 for ( ; outlen > 0; outlen -= chunk, out += chunk) {
731 if (chunk > drbg->max_request)
732 chunk = drbg->max_request;
733 ret = RAND_DRBG_generate(drbg, out, chunk, 0, additional, additional_len);
740 if (additional_len != 0)
741 OPENSSL_secure_clear_free(additional, additional_len);
747 * Set the RAND_DRBG callbacks for obtaining entropy and nonce.
749 * Setting the callbacks is allowed only if the drbg has not been
750 * initialized yet. Otherwise, the operation will fail.
752 * Returns 1 on success, 0 on failure.
754 int RAND_DRBG_set_callbacks(RAND_DRBG *drbg,
755 RAND_DRBG_get_entropy_fn get_entropy,
756 RAND_DRBG_cleanup_entropy_fn cleanup_entropy,
757 RAND_DRBG_get_nonce_fn get_nonce,
758 RAND_DRBG_cleanup_nonce_fn cleanup_nonce)
760 if (drbg->state != DRBG_UNINITIALISED
761 || drbg->parent != NULL)
763 drbg->get_entropy = get_entropy;
764 drbg->cleanup_entropy = cleanup_entropy;
765 drbg->get_nonce = get_nonce;
766 drbg->cleanup_nonce = cleanup_nonce;
771 * Set the reseed interval.
773 * The drbg will reseed automatically whenever the number of generate
774 * requests exceeds the given reseed interval. If the reseed interval
775 * is 0, then this feature is disabled.
777 * Returns 1 on success, 0 on failure.
779 int RAND_DRBG_set_reseed_interval(RAND_DRBG *drbg, unsigned int interval)
781 if (interval > MAX_RESEED_INTERVAL)
783 drbg->reseed_interval = interval;
788 * Set the reseed time interval.
790 * The drbg will reseed automatically whenever the time elapsed since
791 * the last reseeding exceeds the given reseed time interval. For safety,
792 * a reseeding will also occur if the clock has been reset to a smaller
795 * Returns 1 on success, 0 on failure.
797 int RAND_DRBG_set_reseed_time_interval(RAND_DRBG *drbg, time_t interval)
799 if (interval > MAX_RESEED_TIME_INTERVAL)
801 drbg->reseed_time_interval = interval;
806 * Set the default values for reseed (time) intervals of new DRBG instances
808 * The default values can be set independently for master DRBG instances
809 * (without a parent) and slave DRBG instances (with parent).
811 * Returns 1 on success, 0 on failure.
814 int RAND_DRBG_set_reseed_defaults(
815 unsigned int _master_reseed_interval,
816 unsigned int _slave_reseed_interval,
817 time_t _master_reseed_time_interval,
818 time_t _slave_reseed_time_interval
821 if (_master_reseed_interval > MAX_RESEED_INTERVAL
822 || _slave_reseed_interval > MAX_RESEED_INTERVAL)
825 if (_master_reseed_time_interval > MAX_RESEED_TIME_INTERVAL
826 || _slave_reseed_time_interval > MAX_RESEED_TIME_INTERVAL)
829 master_reseed_interval = _master_reseed_interval;
830 slave_reseed_interval = _slave_reseed_interval;
832 master_reseed_time_interval = _master_reseed_time_interval;
833 slave_reseed_time_interval = _slave_reseed_time_interval;
839 * Locks the given drbg. Locking a drbg which does not have locking
840 * enabled is considered a successful no-op.
842 * Returns 1 on success, 0 on failure.
844 int rand_drbg_lock(RAND_DRBG *drbg)
846 if (drbg->lock != NULL)
847 return CRYPTO_THREAD_write_lock(drbg->lock);
853 * Unlocks the given drbg. Unlocking a drbg which does not have locking
854 * enabled is considered a successful no-op.
856 * Returns 1 on success, 0 on failure.
858 int rand_drbg_unlock(RAND_DRBG *drbg)
860 if (drbg->lock != NULL)
861 return CRYPTO_THREAD_unlock(drbg->lock);
867 * Enables locking for the given drbg
869 * Locking can only be enabled if the random generator
870 * is in the uninitialized state.
872 * Returns 1 on success, 0 on failure.
874 int rand_drbg_enable_locking(RAND_DRBG *drbg)
876 if (drbg->state != DRBG_UNINITIALISED) {
877 RANDerr(RAND_F_RAND_DRBG_ENABLE_LOCKING,
878 RAND_R_DRBG_ALREADY_INITIALIZED);
882 if (drbg->lock == NULL) {
883 if (drbg->parent != NULL && drbg->parent->lock == NULL) {
884 RANDerr(RAND_F_RAND_DRBG_ENABLE_LOCKING,
885 RAND_R_PARENT_LOCKING_NOT_ENABLED);
889 drbg->lock = CRYPTO_THREAD_lock_new();
890 if (drbg->lock == NULL) {
891 RANDerr(RAND_F_RAND_DRBG_ENABLE_LOCKING,
892 RAND_R_FAILED_TO_CREATE_LOCK);
901 * Get and set the EXDATA
903 int RAND_DRBG_set_ex_data(RAND_DRBG *drbg, int idx, void *arg)
905 return CRYPTO_set_ex_data(&drbg->ex_data, idx, arg);
908 void *RAND_DRBG_get_ex_data(const RAND_DRBG *drbg, int idx)
910 return CRYPTO_get_ex_data(&drbg->ex_data, idx);
915 * The following functions provide a RAND_METHOD that works on the
916 * global DRBG. They lock.
920 * Allocates a new global DRBG on the secure heap (if enabled) and
921 * initializes it with default settings.
923 * Returns a pointer to the new DRBG instance on success, NULL on failure.
925 static RAND_DRBG *drbg_setup(RAND_DRBG *parent, int drbg_type)
929 drbg = RAND_DRBG_secure_new(rand_drbg_type[drbg_type],
930 rand_drbg_flags[drbg_type], parent);
934 /* Only the master DRBG needs to have a lock */
935 if (parent == NULL && rand_drbg_enable_locking(drbg) == 0)
938 /* enable seed propagation */
939 tsan_store(&drbg->reseed_prop_counter, 1);
942 * Ignore instantiation error to support just-in-time instantiation.
944 * The state of the drbg will be checked in RAND_DRBG_generate() and
945 * an automatic recovery is attempted.
947 (void)RAND_DRBG_instantiate(drbg,
948 (const unsigned char *) ossl_pers_string,
949 sizeof(ossl_pers_string) - 1);
953 RAND_DRBG_free(drbg);
958 * Initialize the global DRBGs on first use.
959 * Returns 1 on success, 0 on failure.
961 DEFINE_RUN_ONCE_STATIC(do_rand_drbg_init)
964 * ensure that libcrypto is initialized, otherwise the
965 * DRBG locks are not cleaned up properly
967 if (!OPENSSL_init_crypto(0, NULL))
970 if (!CRYPTO_THREAD_init_local(&private_drbg, NULL))
973 if (!CRYPTO_THREAD_init_local(&public_drbg, NULL))
976 master_drbg = drbg_setup(NULL, RAND_DRBG_TYPE_MASTER);
977 if (master_drbg == NULL)
983 CRYPTO_THREAD_cleanup_local(&public_drbg);
985 CRYPTO_THREAD_cleanup_local(&private_drbg);
989 /* Clean up the global DRBGs before exit */
990 void rand_drbg_cleanup_int(void)
992 if (master_drbg != NULL) {
993 RAND_DRBG_free(master_drbg);
996 CRYPTO_THREAD_cleanup_local(&private_drbg);
997 CRYPTO_THREAD_cleanup_local(&public_drbg);
1001 void drbg_delete_thread_state(void)
1005 drbg = CRYPTO_THREAD_get_local(&public_drbg);
1006 CRYPTO_THREAD_set_local(&public_drbg, NULL);
1007 RAND_DRBG_free(drbg);
1009 drbg = CRYPTO_THREAD_get_local(&private_drbg);
1010 CRYPTO_THREAD_set_local(&private_drbg, NULL);
1011 RAND_DRBG_free(drbg);
1014 /* Implements the default OpenSSL RAND_bytes() method */
1015 static int drbg_bytes(unsigned char *out, int count)
1018 RAND_DRBG *drbg = RAND_DRBG_get0_public();
1023 ret = RAND_DRBG_bytes(drbg, out, count);
1029 * Calculates the minimum length of a full entropy buffer
1030 * which is necessary to seed (i.e. instantiate) the DRBG
1033 * NOTE: There is a copy of this function in drbgtest.c.
1034 * If you change anything here, you need to update
1035 * the copy accordingly.
1037 static size_t rand_drbg_seedlen(RAND_DRBG *drbg)
1040 * If no os entropy source is available then RAND_seed(buffer, bufsize)
1041 * is expected to succeed if and only if the buffer length satisfies
1042 * the following requirements, which follow from the calculations
1043 * in RAND_DRBG_instantiate().
1045 size_t min_entropy = drbg->strength;
1046 size_t min_entropylen = drbg->min_entropylen;
1049 * Extra entropy for the random nonce in the absence of a
1050 * get_nonce callback, see comment in RAND_DRBG_instantiate().
1052 if (drbg->min_noncelen > 0 && drbg->get_nonce == NULL) {
1053 min_entropy += drbg->strength / 2;
1054 min_entropylen += drbg->min_noncelen;
1058 * Convert entropy requirement from bits to bytes
1059 * (dividing by 8 without rounding upwards, because
1060 * all entropy requirements are divisible by 8).
1064 /* Return a value that satisfies both requirements */
1065 return min_entropy > min_entropylen ? min_entropy : min_entropylen;
1068 /* Implements the default OpenSSL RAND_add() method */
1069 static int drbg_add(const void *buf, int num, double randomness)
1072 RAND_DRBG *drbg = RAND_DRBG_get0_master();
1079 if (num < 0 || randomness < 0.0)
1082 seedlen = rand_drbg_seedlen(drbg);
1084 buflen = (size_t)num;
1086 if (buflen < seedlen || randomness < (double) seedlen) {
1087 #if defined(OPENSSL_RAND_SEED_NONE)
1089 * If no os entropy source is available, a reseeding will fail
1090 * inevitably. So we use a trick to mix the buffer contents into
1091 * the DRBG state without forcing a reseeding: we generate a
1092 * dummy random byte, using the buffer content as additional data.
1094 unsigned char dummy[1];
1096 return RAND_DRBG_generate(drbg, dummy, sizeof(dummy), 0, buf, buflen);
1099 * If an os entropy source is avaible then we declare the buffer content
1100 * as additional data by setting randomness to zero and trigger a regular
1108 if (randomness > (double)seedlen) {
1110 * The purpose of this check is to bound |randomness| by a
1111 * relatively small value in order to prevent an integer
1112 * overflow when multiplying by 8 in the rand_drbg_restart()
1113 * call below. Note that randomness is measured in bytes,
1114 * not bits, so this value corresponds to eight times the
1115 * security strength.
1117 randomness = (double)seedlen;
1120 rand_drbg_lock(drbg);
1121 ret = rand_drbg_restart(drbg, buf, buflen, (size_t)(8 * randomness));
1122 rand_drbg_unlock(drbg);
1127 /* Implements the default OpenSSL RAND_seed() method */
1128 static int drbg_seed(const void *buf, int num)
1130 return drbg_add(buf, num, num);
1133 /* Implements the default OpenSSL RAND_status() method */
1134 static int drbg_status(void)
1137 RAND_DRBG *drbg = RAND_DRBG_get0_master();
1142 rand_drbg_lock(drbg);
1143 ret = drbg->state == DRBG_READY ? 1 : 0;
1144 rand_drbg_unlock(drbg);
1149 * Get the master DRBG.
1150 * Returns pointer to the DRBG on success, NULL on failure.
1153 RAND_DRBG *RAND_DRBG_get0_master(void)
1155 if (!RUN_ONCE(&rand_drbg_init, do_rand_drbg_init))
1162 * Get the public DRBG.
1163 * Returns pointer to the DRBG on success, NULL on failure.
1165 RAND_DRBG *RAND_DRBG_get0_public(void)
1169 if (!RUN_ONCE(&rand_drbg_init, do_rand_drbg_init))
1172 drbg = CRYPTO_THREAD_get_local(&public_drbg);
1174 if (!ossl_init_thread_start(OPENSSL_INIT_THREAD_RAND))
1176 drbg = drbg_setup(master_drbg, RAND_DRBG_TYPE_PUBLIC);
1177 CRYPTO_THREAD_set_local(&public_drbg, drbg);
1183 * Get the private DRBG.
1184 * Returns pointer to the DRBG on success, NULL on failure.
1186 RAND_DRBG *RAND_DRBG_get0_private(void)
1190 if (!RUN_ONCE(&rand_drbg_init, do_rand_drbg_init))
1193 drbg = CRYPTO_THREAD_get_local(&private_drbg);
1195 if (!ossl_init_thread_start(OPENSSL_INIT_THREAD_RAND))
1197 drbg = drbg_setup(master_drbg, RAND_DRBG_TYPE_PRIVATE);
1198 CRYPTO_THREAD_set_local(&private_drbg, drbg);
1203 RAND_METHOD rand_meth = {
1212 RAND_METHOD *RAND_OpenSSL(void)