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);
299 OPENSSL_secure_free(drbg);
306 RAND_DRBG *RAND_DRBG_new(int type, unsigned int flags, RAND_DRBG *parent)
308 return rand_drbg_new(0, type, flags, parent);
311 RAND_DRBG *RAND_DRBG_secure_new(int type, unsigned int flags, RAND_DRBG *parent)
313 return rand_drbg_new(1, type, flags, parent);
317 * Uninstantiate |drbg| and free all memory.
319 void RAND_DRBG_free(RAND_DRBG *drbg)
324 if (drbg->meth != NULL)
325 drbg->meth->uninstantiate(drbg);
326 rand_pool_free(drbg->adin_pool);
327 CRYPTO_THREAD_lock_free(drbg->lock);
328 CRYPTO_free_ex_data(CRYPTO_EX_INDEX_DRBG, drbg, &drbg->ex_data);
331 OPENSSL_secure_clear_free(drbg, sizeof(*drbg));
333 OPENSSL_clear_free(drbg, sizeof(*drbg));
337 * Instantiate |drbg|, after it has been initialized. Use |pers| and
338 * |perslen| as prediction-resistance input.
340 * Requires that drbg->lock is already locked for write, if non-null.
342 * Returns 1 on success, 0 on failure.
344 int RAND_DRBG_instantiate(RAND_DRBG *drbg,
345 const unsigned char *pers, size_t perslen)
347 unsigned char *nonce = NULL, *entropy = NULL;
348 size_t noncelen = 0, entropylen = 0;
349 size_t min_entropy = drbg->strength;
350 size_t min_entropylen = drbg->min_entropylen;
351 size_t max_entropylen = drbg->max_entropylen;
353 if (perslen > drbg->max_perslen) {
354 RANDerr(RAND_F_RAND_DRBG_INSTANTIATE,
355 RAND_R_PERSONALISATION_STRING_TOO_LONG);
359 if (drbg->meth == NULL) {
360 RANDerr(RAND_F_RAND_DRBG_INSTANTIATE,
361 RAND_R_NO_DRBG_IMPLEMENTATION_SELECTED);
365 if (drbg->state != DRBG_UNINITIALISED) {
366 RANDerr(RAND_F_RAND_DRBG_INSTANTIATE,
367 drbg->state == DRBG_ERROR ? RAND_R_IN_ERROR_STATE
368 : RAND_R_ALREADY_INSTANTIATED);
372 drbg->state = DRBG_ERROR;
375 * NIST SP800-90Ar1 section 9.1 says you can combine getting the entropy
376 * and nonce in 1 call by increasing the entropy with 50% and increasing
377 * the minimum length to accomadate the length of the nonce.
378 * We do this in case a nonce is require and get_nonce is NULL.
380 if (drbg->min_noncelen > 0 && drbg->get_nonce == NULL) {
381 min_entropy += drbg->strength / 2;
382 min_entropylen += drbg->min_noncelen;
383 max_entropylen += drbg->max_noncelen;
386 drbg->reseed_next_counter = tsan_load(&drbg->reseed_prop_counter);
387 if (drbg->reseed_next_counter) {
388 drbg->reseed_next_counter++;
389 if(!drbg->reseed_next_counter)
390 drbg->reseed_next_counter = 1;
393 if (drbg->get_entropy != NULL)
394 entropylen = drbg->get_entropy(drbg, &entropy, min_entropy,
395 min_entropylen, max_entropylen, 0);
396 if (entropylen < min_entropylen
397 || entropylen > max_entropylen) {
398 RANDerr(RAND_F_RAND_DRBG_INSTANTIATE, RAND_R_ERROR_RETRIEVING_ENTROPY);
402 if (drbg->min_noncelen > 0 && drbg->get_nonce != NULL) {
403 noncelen = drbg->get_nonce(drbg, &nonce, drbg->strength / 2,
404 drbg->min_noncelen, drbg->max_noncelen);
405 if (noncelen < drbg->min_noncelen || noncelen > drbg->max_noncelen) {
406 RANDerr(RAND_F_RAND_DRBG_INSTANTIATE, RAND_R_ERROR_RETRIEVING_NONCE);
411 if (!drbg->meth->instantiate(drbg, entropy, entropylen,
412 nonce, noncelen, pers, perslen)) {
413 RANDerr(RAND_F_RAND_DRBG_INSTANTIATE, RAND_R_ERROR_INSTANTIATING_DRBG);
417 drbg->state = DRBG_READY;
418 drbg->reseed_gen_counter = 1;
419 drbg->reseed_time = time(NULL);
420 tsan_store(&drbg->reseed_prop_counter, drbg->reseed_next_counter);
423 if (entropy != NULL && drbg->cleanup_entropy != NULL)
424 drbg->cleanup_entropy(drbg, entropy, entropylen);
425 if (nonce != NULL && drbg->cleanup_nonce != NULL)
426 drbg->cleanup_nonce(drbg, nonce, noncelen);
427 if (drbg->state == DRBG_READY)
433 * Uninstantiate |drbg|. Must be instantiated before it can be used.
435 * Requires that drbg->lock is already locked for write, if non-null.
437 * Returns 1 on success, 0 on failure.
439 int RAND_DRBG_uninstantiate(RAND_DRBG *drbg)
441 int index = -1, type, flags;
442 if (drbg->meth == NULL) {
443 RANDerr(RAND_F_RAND_DRBG_UNINSTANTIATE,
444 RAND_R_NO_DRBG_IMPLEMENTATION_SELECTED);
448 /* Clear the entire drbg->ctr struct, then reset some important
449 * members of the drbg->ctr struct (e.g. keysize, df_ks) to their
452 drbg->meth->uninstantiate(drbg);
454 /* The reset uses the default values for type and flags */
455 if (drbg->flags & RAND_DRBG_FLAG_MASTER)
456 index = RAND_DRBG_TYPE_MASTER;
457 else if (drbg->flags & RAND_DRBG_FLAG_PRIVATE)
458 index = RAND_DRBG_TYPE_PRIVATE;
459 else if (drbg->flags & RAND_DRBG_FLAG_PUBLIC)
460 index = RAND_DRBG_TYPE_PUBLIC;
463 flags = rand_drbg_flags[index];
464 type = rand_drbg_type[index];
469 return RAND_DRBG_set(drbg, type, flags);
473 * Reseed |drbg|, mixing in the specified data
475 * Requires that drbg->lock is already locked for write, if non-null.
477 * Returns 1 on success, 0 on failure.
479 int RAND_DRBG_reseed(RAND_DRBG *drbg,
480 const unsigned char *adin, size_t adinlen,
481 int prediction_resistance)
483 unsigned char *entropy = NULL;
484 size_t entropylen = 0;
486 if (drbg->state == DRBG_ERROR) {
487 RANDerr(RAND_F_RAND_DRBG_RESEED, RAND_R_IN_ERROR_STATE);
490 if (drbg->state == DRBG_UNINITIALISED) {
491 RANDerr(RAND_F_RAND_DRBG_RESEED, RAND_R_NOT_INSTANTIATED);
497 } else if (adinlen > drbg->max_adinlen) {
498 RANDerr(RAND_F_RAND_DRBG_RESEED, RAND_R_ADDITIONAL_INPUT_TOO_LONG);
502 drbg->state = DRBG_ERROR;
504 drbg->reseed_next_counter = tsan_load(&drbg->reseed_prop_counter);
505 if (drbg->reseed_next_counter) {
506 drbg->reseed_next_counter++;
507 if(!drbg->reseed_next_counter)
508 drbg->reseed_next_counter = 1;
511 if (drbg->get_entropy != NULL)
512 entropylen = drbg->get_entropy(drbg, &entropy, drbg->strength,
513 drbg->min_entropylen,
514 drbg->max_entropylen,
515 prediction_resistance);
516 if (entropylen < drbg->min_entropylen
517 || entropylen > drbg->max_entropylen) {
518 RANDerr(RAND_F_RAND_DRBG_RESEED, RAND_R_ERROR_RETRIEVING_ENTROPY);
522 if (!drbg->meth->reseed(drbg, entropy, entropylen, adin, adinlen))
525 drbg->state = DRBG_READY;
526 drbg->reseed_gen_counter = 1;
527 drbg->reseed_time = time(NULL);
528 tsan_store(&drbg->reseed_prop_counter, drbg->reseed_next_counter);
531 if (entropy != NULL && drbg->cleanup_entropy != NULL)
532 drbg->cleanup_entropy(drbg, entropy, entropylen);
533 if (drbg->state == DRBG_READY)
539 * Restart |drbg|, using the specified entropy or additional input
541 * Tries its best to get the drbg instantiated by all means,
542 * regardless of its current state.
544 * Optionally, a |buffer| of |len| random bytes can be passed,
545 * which is assumed to contain at least |entropy| bits of entropy.
547 * If |entropy| > 0, the buffer content is used as entropy input.
549 * If |entropy| == 0, the buffer content is used as additional input
551 * Returns 1 on success, 0 on failure.
553 * This function is used internally only.
555 int rand_drbg_restart(RAND_DRBG *drbg,
556 const unsigned char *buffer, size_t len, size_t entropy)
559 const unsigned char *adin = NULL;
562 if (drbg->pool != NULL) {
563 RANDerr(RAND_F_RAND_DRBG_RESTART, ERR_R_INTERNAL_ERROR);
564 drbg->state = DRBG_ERROR;
565 rand_pool_free(drbg->pool);
570 if (buffer != NULL) {
572 if (drbg->max_entropylen < len) {
573 RANDerr(RAND_F_RAND_DRBG_RESTART,
574 RAND_R_ENTROPY_INPUT_TOO_LONG);
575 drbg->state = DRBG_ERROR;
579 if (entropy > 8 * len) {
580 RANDerr(RAND_F_RAND_DRBG_RESTART, RAND_R_ENTROPY_OUT_OF_RANGE);
581 drbg->state = DRBG_ERROR;
585 /* will be picked up by the rand_drbg_get_entropy() callback */
586 drbg->pool = rand_pool_attach(buffer, len, entropy);
587 if (drbg->pool == NULL)
590 if (drbg->max_adinlen < len) {
591 RANDerr(RAND_F_RAND_DRBG_RESTART,
592 RAND_R_ADDITIONAL_INPUT_TOO_LONG);
593 drbg->state = DRBG_ERROR;
601 /* repair error state */
602 if (drbg->state == DRBG_ERROR)
603 RAND_DRBG_uninstantiate(drbg);
605 /* repair uninitialized state */
606 if (drbg->state == DRBG_UNINITIALISED) {
607 /* reinstantiate drbg */
608 RAND_DRBG_instantiate(drbg,
609 (const unsigned char *) ossl_pers_string,
610 sizeof(ossl_pers_string) - 1);
611 /* already reseeded. prevent second reseeding below */
612 reseeded = (drbg->state == DRBG_READY);
615 /* refresh current state if entropy or additional input has been provided */
616 if (drbg->state == DRBG_READY) {
619 * mix in additional input without reseeding
621 * Similar to RAND_DRBG_reseed(), but the provided additional
622 * data |adin| is mixed into the current state without pulling
623 * entropy from the trusted entropy source using get_entropy().
624 * This is not a reseeding in the strict sense of NIST SP 800-90A.
626 drbg->meth->reseed(drbg, adin, adinlen, NULL, 0);
627 } else if (reseeded == 0) {
628 /* do a full reseeding if it has not been done yet above */
629 RAND_DRBG_reseed(drbg, NULL, 0, 0);
633 rand_pool_free(drbg->pool);
636 return drbg->state == DRBG_READY;
640 * Generate |outlen| bytes into the buffer at |out|. Reseed if we need
641 * to or if |prediction_resistance| is set. Additional input can be
642 * sent in |adin| and |adinlen|.
644 * Requires that drbg->lock is already locked for write, if non-null.
646 * Returns 1 on success, 0 on failure.
649 int RAND_DRBG_generate(RAND_DRBG *drbg, unsigned char *out, size_t outlen,
650 int prediction_resistance,
651 const unsigned char *adin, size_t adinlen)
653 int reseed_required = 0;
655 if (drbg->state != DRBG_READY) {
656 /* try to recover from previous errors */
657 rand_drbg_restart(drbg, NULL, 0, 0);
659 if (drbg->state == DRBG_ERROR) {
660 RANDerr(RAND_F_RAND_DRBG_GENERATE, RAND_R_IN_ERROR_STATE);
663 if (drbg->state == DRBG_UNINITIALISED) {
664 RANDerr(RAND_F_RAND_DRBG_GENERATE, RAND_R_NOT_INSTANTIATED);
669 if (outlen > drbg->max_request) {
670 RANDerr(RAND_F_RAND_DRBG_GENERATE, RAND_R_REQUEST_TOO_LARGE_FOR_DRBG);
673 if (adinlen > drbg->max_adinlen) {
674 RANDerr(RAND_F_RAND_DRBG_GENERATE, RAND_R_ADDITIONAL_INPUT_TOO_LONG);
678 if (drbg->fork_count != rand_fork_count) {
679 drbg->fork_count = rand_fork_count;
683 if (drbg->reseed_interval > 0) {
684 if (drbg->reseed_gen_counter > drbg->reseed_interval)
687 if (drbg->reseed_time_interval > 0) {
688 time_t now = time(NULL);
689 if (now < drbg->reseed_time
690 || now - drbg->reseed_time >= drbg->reseed_time_interval)
693 if (drbg->parent != NULL) {
694 unsigned int reseed_counter = tsan_load(&drbg->reseed_prop_counter);
695 if (reseed_counter > 0
696 && tsan_load(&drbg->parent->reseed_prop_counter)
701 if (reseed_required || prediction_resistance) {
702 if (!RAND_DRBG_reseed(drbg, adin, adinlen, prediction_resistance)) {
703 RANDerr(RAND_F_RAND_DRBG_GENERATE, RAND_R_RESEED_ERROR);
710 if (!drbg->meth->generate(drbg, out, outlen, adin, adinlen)) {
711 drbg->state = DRBG_ERROR;
712 RANDerr(RAND_F_RAND_DRBG_GENERATE, RAND_R_GENERATE_ERROR);
716 drbg->reseed_gen_counter++;
722 * Generates |outlen| random bytes and stores them in |out|. It will
723 * using the given |drbg| to generate the bytes.
725 * Requires that drbg->lock is already locked for write, if non-null.
727 * Returns 1 on success 0 on failure.
729 int RAND_DRBG_bytes(RAND_DRBG *drbg, unsigned char *out, size_t outlen)
731 unsigned char *additional = NULL;
732 size_t additional_len;
736 if (drbg->adin_pool == NULL) {
739 drbg->adin_pool = rand_pool_new(0, 0, drbg->max_adinlen);
740 if (drbg->adin_pool == NULL)
744 additional_len = rand_drbg_get_additional_data(drbg->adin_pool,
747 for ( ; outlen > 0; outlen -= chunk, out += chunk) {
749 if (chunk > drbg->max_request)
750 chunk = drbg->max_request;
751 ret = RAND_DRBG_generate(drbg, out, chunk, 0, additional, additional_len);
758 if (additional != NULL)
759 rand_drbg_cleanup_additional_data(drbg->adin_pool, additional);
765 * Set the RAND_DRBG callbacks for obtaining entropy and nonce.
767 * Setting the callbacks is allowed only if the drbg has not been
768 * initialized yet. Otherwise, the operation will fail.
770 * Returns 1 on success, 0 on failure.
772 int RAND_DRBG_set_callbacks(RAND_DRBG *drbg,
773 RAND_DRBG_get_entropy_fn get_entropy,
774 RAND_DRBG_cleanup_entropy_fn cleanup_entropy,
775 RAND_DRBG_get_nonce_fn get_nonce,
776 RAND_DRBG_cleanup_nonce_fn cleanup_nonce)
778 if (drbg->state != DRBG_UNINITIALISED
779 || drbg->parent != NULL)
781 drbg->get_entropy = get_entropy;
782 drbg->cleanup_entropy = cleanup_entropy;
783 drbg->get_nonce = get_nonce;
784 drbg->cleanup_nonce = cleanup_nonce;
789 * Set the reseed interval.
791 * The drbg will reseed automatically whenever the number of generate
792 * requests exceeds the given reseed interval. If the reseed interval
793 * is 0, then this feature is disabled.
795 * Returns 1 on success, 0 on failure.
797 int RAND_DRBG_set_reseed_interval(RAND_DRBG *drbg, unsigned int interval)
799 if (interval > MAX_RESEED_INTERVAL)
801 drbg->reseed_interval = interval;
806 * Set the reseed time interval.
808 * The drbg will reseed automatically whenever the time elapsed since
809 * the last reseeding exceeds the given reseed time interval. For safety,
810 * a reseeding will also occur if the clock has been reset to a smaller
813 * Returns 1 on success, 0 on failure.
815 int RAND_DRBG_set_reseed_time_interval(RAND_DRBG *drbg, time_t interval)
817 if (interval > MAX_RESEED_TIME_INTERVAL)
819 drbg->reseed_time_interval = interval;
824 * Set the default values for reseed (time) intervals of new DRBG instances
826 * The default values can be set independently for master DRBG instances
827 * (without a parent) and slave DRBG instances (with parent).
829 * Returns 1 on success, 0 on failure.
832 int RAND_DRBG_set_reseed_defaults(
833 unsigned int _master_reseed_interval,
834 unsigned int _slave_reseed_interval,
835 time_t _master_reseed_time_interval,
836 time_t _slave_reseed_time_interval
839 if (_master_reseed_interval > MAX_RESEED_INTERVAL
840 || _slave_reseed_interval > MAX_RESEED_INTERVAL)
843 if (_master_reseed_time_interval > MAX_RESEED_TIME_INTERVAL
844 || _slave_reseed_time_interval > MAX_RESEED_TIME_INTERVAL)
847 master_reseed_interval = _master_reseed_interval;
848 slave_reseed_interval = _slave_reseed_interval;
850 master_reseed_time_interval = _master_reseed_time_interval;
851 slave_reseed_time_interval = _slave_reseed_time_interval;
857 * Locks the given drbg. Locking a drbg which does not have locking
858 * enabled is considered a successful no-op.
860 * Returns 1 on success, 0 on failure.
862 int rand_drbg_lock(RAND_DRBG *drbg)
864 if (drbg->lock != NULL)
865 return CRYPTO_THREAD_write_lock(drbg->lock);
871 * Unlocks the given drbg. Unlocking a drbg which does not have locking
872 * enabled is considered a successful no-op.
874 * Returns 1 on success, 0 on failure.
876 int rand_drbg_unlock(RAND_DRBG *drbg)
878 if (drbg->lock != NULL)
879 return CRYPTO_THREAD_unlock(drbg->lock);
885 * Enables locking for the given drbg
887 * Locking can only be enabled if the random generator
888 * is in the uninitialized state.
890 * Returns 1 on success, 0 on failure.
892 int rand_drbg_enable_locking(RAND_DRBG *drbg)
894 if (drbg->state != DRBG_UNINITIALISED) {
895 RANDerr(RAND_F_RAND_DRBG_ENABLE_LOCKING,
896 RAND_R_DRBG_ALREADY_INITIALIZED);
900 if (drbg->lock == NULL) {
901 if (drbg->parent != NULL && drbg->parent->lock == NULL) {
902 RANDerr(RAND_F_RAND_DRBG_ENABLE_LOCKING,
903 RAND_R_PARENT_LOCKING_NOT_ENABLED);
907 drbg->lock = CRYPTO_THREAD_lock_new();
908 if (drbg->lock == NULL) {
909 RANDerr(RAND_F_RAND_DRBG_ENABLE_LOCKING,
910 RAND_R_FAILED_TO_CREATE_LOCK);
919 * Get and set the EXDATA
921 int RAND_DRBG_set_ex_data(RAND_DRBG *drbg, int idx, void *arg)
923 return CRYPTO_set_ex_data(&drbg->ex_data, idx, arg);
926 void *RAND_DRBG_get_ex_data(const RAND_DRBG *drbg, int idx)
928 return CRYPTO_get_ex_data(&drbg->ex_data, idx);
933 * The following functions provide a RAND_METHOD that works on the
934 * global DRBG. They lock.
938 * Allocates a new global DRBG on the secure heap (if enabled) and
939 * initializes it with default settings.
941 * Returns a pointer to the new DRBG instance on success, NULL on failure.
943 static RAND_DRBG *drbg_setup(RAND_DRBG *parent, int drbg_type)
947 drbg = RAND_DRBG_secure_new(rand_drbg_type[drbg_type],
948 rand_drbg_flags[drbg_type], parent);
952 /* Only the master DRBG needs to have a lock */
953 if (parent == NULL && rand_drbg_enable_locking(drbg) == 0)
956 /* enable seed propagation */
957 tsan_store(&drbg->reseed_prop_counter, 1);
960 * Ignore instantiation error to support just-in-time instantiation.
962 * The state of the drbg will be checked in RAND_DRBG_generate() and
963 * an automatic recovery is attempted.
965 (void)RAND_DRBG_instantiate(drbg,
966 (const unsigned char *) ossl_pers_string,
967 sizeof(ossl_pers_string) - 1);
971 RAND_DRBG_free(drbg);
976 * Initialize the global DRBGs on first use.
977 * Returns 1 on success, 0 on failure.
979 DEFINE_RUN_ONCE_STATIC(do_rand_drbg_init)
982 * ensure that libcrypto is initialized, otherwise the
983 * DRBG locks are not cleaned up properly
985 if (!OPENSSL_init_crypto(0, NULL))
988 if (!CRYPTO_THREAD_init_local(&private_drbg, NULL))
991 if (!CRYPTO_THREAD_init_local(&public_drbg, NULL))
994 master_drbg = drbg_setup(NULL, RAND_DRBG_TYPE_MASTER);
995 if (master_drbg == NULL)
1001 CRYPTO_THREAD_cleanup_local(&public_drbg);
1003 CRYPTO_THREAD_cleanup_local(&private_drbg);
1007 /* Clean up the global DRBGs before exit */
1008 void rand_drbg_cleanup_int(void)
1010 if (master_drbg != NULL) {
1011 RAND_DRBG_free(master_drbg);
1014 CRYPTO_THREAD_cleanup_local(&private_drbg);
1015 CRYPTO_THREAD_cleanup_local(&public_drbg);
1019 void drbg_delete_thread_state(void)
1023 drbg = CRYPTO_THREAD_get_local(&public_drbg);
1024 CRYPTO_THREAD_set_local(&public_drbg, NULL);
1025 RAND_DRBG_free(drbg);
1027 drbg = CRYPTO_THREAD_get_local(&private_drbg);
1028 CRYPTO_THREAD_set_local(&private_drbg, NULL);
1029 RAND_DRBG_free(drbg);
1032 /* Implements the default OpenSSL RAND_bytes() method */
1033 static int drbg_bytes(unsigned char *out, int count)
1036 RAND_DRBG *drbg = RAND_DRBG_get0_public();
1041 ret = RAND_DRBG_bytes(drbg, out, count);
1047 * Calculates the minimum length of a full entropy buffer
1048 * which is necessary to seed (i.e. instantiate) the DRBG
1051 * NOTE: There is a copy of this function in drbgtest.c.
1052 * If you change anything here, you need to update
1053 * the copy accordingly.
1055 static size_t rand_drbg_seedlen(RAND_DRBG *drbg)
1058 * If no os entropy source is available then RAND_seed(buffer, bufsize)
1059 * is expected to succeed if and only if the buffer length satisfies
1060 * the following requirements, which follow from the calculations
1061 * in RAND_DRBG_instantiate().
1063 size_t min_entropy = drbg->strength;
1064 size_t min_entropylen = drbg->min_entropylen;
1067 * Extra entropy for the random nonce in the absence of a
1068 * get_nonce callback, see comment in RAND_DRBG_instantiate().
1070 if (drbg->min_noncelen > 0 && drbg->get_nonce == NULL) {
1071 min_entropy += drbg->strength / 2;
1072 min_entropylen += drbg->min_noncelen;
1076 * Convert entropy requirement from bits to bytes
1077 * (dividing by 8 without rounding upwards, because
1078 * all entropy requirements are divisible by 8).
1082 /* Return a value that satisfies both requirements */
1083 return min_entropy > min_entropylen ? min_entropy : min_entropylen;
1086 /* Implements the default OpenSSL RAND_add() method */
1087 static int drbg_add(const void *buf, int num, double randomness)
1090 RAND_DRBG *drbg = RAND_DRBG_get0_master();
1097 if (num < 0 || randomness < 0.0)
1100 rand_drbg_lock(drbg);
1101 seedlen = rand_drbg_seedlen(drbg);
1103 buflen = (size_t)num;
1105 if (buflen < seedlen || randomness < (double) seedlen) {
1106 #if defined(OPENSSL_RAND_SEED_NONE)
1108 * If no os entropy source is available, a reseeding will fail
1109 * inevitably. So we use a trick to mix the buffer contents into
1110 * the DRBG state without forcing a reseeding: we generate a
1111 * dummy random byte, using the buffer content as additional data.
1112 * Note: This won't work with RAND_DRBG_FLAG_CTR_NO_DF.
1114 unsigned char dummy[1];
1116 ret = RAND_DRBG_generate(drbg, dummy, sizeof(dummy), 0, buf, buflen);
1117 rand_drbg_unlock(drbg);
1121 * If an os entropy source is avaible then we declare the buffer content
1122 * as additional data by setting randomness to zero and trigger a regular
1130 if (randomness > (double)seedlen) {
1132 * The purpose of this check is to bound |randomness| by a
1133 * relatively small value in order to prevent an integer
1134 * overflow when multiplying by 8 in the rand_drbg_restart()
1135 * call below. Note that randomness is measured in bytes,
1136 * not bits, so this value corresponds to eight times the
1137 * security strength.
1139 randomness = (double)seedlen;
1142 ret = rand_drbg_restart(drbg, buf, buflen, (size_t)(8 * randomness));
1143 rand_drbg_unlock(drbg);
1148 /* Implements the default OpenSSL RAND_seed() method */
1149 static int drbg_seed(const void *buf, int num)
1151 return drbg_add(buf, num, num);
1154 /* Implements the default OpenSSL RAND_status() method */
1155 static int drbg_status(void)
1158 RAND_DRBG *drbg = RAND_DRBG_get0_master();
1163 rand_drbg_lock(drbg);
1164 ret = drbg->state == DRBG_READY ? 1 : 0;
1165 rand_drbg_unlock(drbg);
1170 * Get the master DRBG.
1171 * Returns pointer to the DRBG on success, NULL on failure.
1174 RAND_DRBG *RAND_DRBG_get0_master(void)
1176 if (!RUN_ONCE(&rand_drbg_init, do_rand_drbg_init))
1183 * Get the public DRBG.
1184 * Returns pointer to the DRBG on success, NULL on failure.
1186 RAND_DRBG *RAND_DRBG_get0_public(void)
1190 if (!RUN_ONCE(&rand_drbg_init, do_rand_drbg_init))
1193 drbg = CRYPTO_THREAD_get_local(&public_drbg);
1195 if (!ossl_init_thread_start(OPENSSL_INIT_THREAD_RAND))
1197 drbg = drbg_setup(master_drbg, RAND_DRBG_TYPE_PUBLIC);
1198 CRYPTO_THREAD_set_local(&public_drbg, drbg);
1204 * Get the private DRBG.
1205 * Returns pointer to the DRBG on success, NULL on failure.
1207 RAND_DRBG *RAND_DRBG_get0_private(void)
1211 if (!RUN_ONCE(&rand_drbg_init, do_rand_drbg_init))
1214 drbg = CRYPTO_THREAD_get_local(&private_drbg);
1216 if (!ossl_init_thread_start(OPENSSL_INIT_THREAD_RAND))
1218 drbg = drbg_setup(master_drbg, RAND_DRBG_TYPE_PRIVATE);
1219 CRYPTO_THREAD_set_local(&private_drbg, drbg);
1224 RAND_METHOD rand_meth = {
1233 RAND_METHOD *RAND_OpenSSL(void)