2 * Copyright 2011-2018 The OpenSSL Project Authors. All Rights Reserved.
4 * Licensed under the Apache License 2.0 (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 typedef struct drbg_global_st {
35 * The three shared DRBG instances
37 * There are three shared DRBG instances: <master>, <public>, and <private>.
43 * Not used directly by the application, only for reseeding the two other
44 * DRBGs. It reseeds itself by pulling either randomness from os entropy
45 * sources or by consuming randomness which was added by RAND_add().
47 * The <master> DRBG is a global instance which is accessed concurrently by
48 * all threads. The necessary locking is managed automatically by its child
49 * DRBG instances during reseeding.
51 RAND_DRBG *master_drbg;
55 * Used by default for generating random bytes using RAND_bytes().
57 * The <public> DRBG is thread-local, i.e., there is one instance per
60 CRYPTO_THREAD_LOCAL public_drbg;
64 * Used by default for generating private keys using RAND_priv_bytes()
66 * The <private> DRBG is thread-local, i.e., there is one instance per
69 CRYPTO_THREAD_LOCAL private_drbg;
72 typedef struct drbg_nonce_global_st {
73 CRYPTO_RWLOCK *rand_nonce_lock;
77 /* NIST SP 800-90A DRBG recommends the use of a personalization string. */
78 static const char ossl_pers_string[] = DRBG_DEFAULT_PERS_STRING;
80 #define RAND_DRBG_TYPE_FLAGS ( \
81 RAND_DRBG_FLAG_MASTER | RAND_DRBG_FLAG_PUBLIC | RAND_DRBG_FLAG_PRIVATE )
83 #define RAND_DRBG_TYPE_MASTER 0
84 #define RAND_DRBG_TYPE_PUBLIC 1
85 #define RAND_DRBG_TYPE_PRIVATE 2
88 static int rand_drbg_type[3] = {
89 RAND_DRBG_TYPE, /* Master */
90 RAND_DRBG_TYPE, /* Public */
91 RAND_DRBG_TYPE /* Private */
93 static unsigned int rand_drbg_flags[3] = {
94 RAND_DRBG_FLAGS | RAND_DRBG_FLAG_MASTER, /* Master */
95 RAND_DRBG_FLAGS | RAND_DRBG_FLAG_PUBLIC, /* Public */
96 RAND_DRBG_FLAGS | RAND_DRBG_FLAG_PRIVATE /* Private */
99 static unsigned int master_reseed_interval = MASTER_RESEED_INTERVAL;
100 static unsigned int slave_reseed_interval = SLAVE_RESEED_INTERVAL;
102 static time_t master_reseed_time_interval = MASTER_RESEED_TIME_INTERVAL;
103 static time_t slave_reseed_time_interval = SLAVE_RESEED_TIME_INTERVAL;
105 /* A logical OR of all used DRBG flag bits (currently there is only one) */
106 static const unsigned int rand_drbg_used_flags =
107 RAND_DRBG_FLAG_CTR_NO_DF | RAND_DRBG_FLAG_HMAC | RAND_DRBG_TYPE_FLAGS;
110 static RAND_DRBG *drbg_setup(OPENSSL_CTX *ctx, RAND_DRBG *parent, int drbg_type);
112 static RAND_DRBG *rand_drbg_new(OPENSSL_CTX *ctx,
118 static int is_ctr(int type)
121 case NID_aes_128_ctr:
122 case NID_aes_192_ctr:
123 case NID_aes_256_ctr:
130 static int is_digest(int type)
151 * Initialize the OPENSSL_CTX global DRBGs on first use.
152 * Returns the allocated global data on success or NULL on failure.
154 static void *drbg_ossl_ctx_new(OPENSSL_CTX *libctx)
156 DRBG_GLOBAL *dgbl = OPENSSL_zalloc(sizeof(*dgbl));
163 * We need to ensure that base libcrypto thread handling has been
166 OPENSSL_init_crypto(0, NULL);
169 if (!CRYPTO_THREAD_init_local(&dgbl->private_drbg, NULL))
172 if (!CRYPTO_THREAD_init_local(&dgbl->public_drbg, NULL))
175 dgbl->master_drbg = drbg_setup(libctx, NULL, RAND_DRBG_TYPE_MASTER);
176 if (dgbl->master_drbg == NULL)
182 CRYPTO_THREAD_cleanup_local(&dgbl->public_drbg);
184 CRYPTO_THREAD_cleanup_local(&dgbl->private_drbg);
190 static void drbg_ossl_ctx_free(void *vdgbl)
192 DRBG_GLOBAL *dgbl = vdgbl;
194 RAND_DRBG_free(dgbl->master_drbg);
195 CRYPTO_THREAD_cleanup_local(&dgbl->private_drbg);
196 CRYPTO_THREAD_cleanup_local(&dgbl->public_drbg);
201 static const OPENSSL_CTX_METHOD drbg_ossl_ctx_method = {
207 * drbg_ossl_ctx_new() calls drgb_setup() which calls rand_drbg_get_nonce()
208 * which needs to get the rand_nonce_lock out of the OPENSSL_CTX...but since
209 * drbg_ossl_ctx_new() hasn't finished running yet we need the rand_nonce_lock
210 * to be in a different global data object. Otherwise we will go into an
211 * infinite recursion loop.
213 static void *drbg_nonce_ossl_ctx_new(OPENSSL_CTX *libctx)
215 DRBG_NONCE_GLOBAL *dngbl = OPENSSL_zalloc(sizeof(*dngbl));
220 dngbl->rand_nonce_lock = CRYPTO_THREAD_lock_new();
221 if (dngbl->rand_nonce_lock == NULL) {
229 static void drbg_nonce_ossl_ctx_free(void *vdngbl)
231 DRBG_NONCE_GLOBAL *dngbl = vdngbl;
233 CRYPTO_THREAD_lock_free(dngbl->rand_nonce_lock);
238 static const OPENSSL_CTX_METHOD drbg_nonce_ossl_ctx_method = {
239 drbg_nonce_ossl_ctx_new,
240 drbg_nonce_ossl_ctx_free,
243 static DRBG_GLOBAL *drbg_get_global(OPENSSL_CTX *libctx)
245 return openssl_ctx_get_data(libctx, OPENSSL_CTX_DRBG_INDEX,
246 &drbg_ossl_ctx_method);
249 /* Implements the get_nonce() callback (see RAND_DRBG_set_callbacks()) */
250 size_t rand_drbg_get_nonce(RAND_DRBG *drbg,
251 unsigned char **pout,
252 int entropy, size_t min_len, size_t max_len)
256 DRBG_NONCE_GLOBAL *dngbl
257 = openssl_ctx_get_data(drbg->libctx, OPENSSL_CTX_DRBG_NONCE_INDEX,
258 &drbg_nonce_ossl_ctx_method);
267 memset(&data, 0, sizeof(data));
268 pool = rand_pool_new(0, 0, min_len, max_len);
272 if (rand_pool_add_nonce_data(pool) == 0)
275 data.instance = drbg;
276 CRYPTO_atomic_add(&dngbl->rand_nonce_count, 1, &data.count,
277 dngbl->rand_nonce_lock);
279 if (rand_pool_add(pool, (unsigned char *)&data, sizeof(data), 0) == 0)
282 ret = rand_pool_length(pool);
283 *pout = rand_pool_detach(pool);
286 rand_pool_free(pool);
292 * Implements the cleanup_nonce() callback (see RAND_DRBG_set_callbacks())
295 void rand_drbg_cleanup_nonce(RAND_DRBG *drbg,
296 unsigned char *out, size_t outlen)
298 OPENSSL_clear_free(out, outlen);
302 * Set/initialize |drbg| to be of type |type|, with optional |flags|.
304 * If |type| and |flags| are zero, use the defaults
306 * Returns 1 on success, 0 on failure.
308 int RAND_DRBG_set(RAND_DRBG *drbg, int type, unsigned int flags)
312 if (type == 0 && flags == 0) {
313 type = rand_drbg_type[RAND_DRBG_TYPE_MASTER];
314 flags = rand_drbg_flags[RAND_DRBG_TYPE_MASTER];
317 /* If set is called multiple times - clear the old one */
318 if (drbg->type != 0 && (type != drbg->type || flags != drbg->flags)) {
319 drbg->meth->uninstantiate(drbg);
320 rand_pool_free(drbg->adin_pool);
321 drbg->adin_pool = NULL;
324 drbg->state = DRBG_UNINITIALISED;
329 /* Uninitialized; that's okay. */
332 } else if (is_ctr(type)) {
333 ret = drbg_ctr_init(drbg);
334 } else if (is_digest(type)) {
335 if (flags & RAND_DRBG_FLAG_HMAC)
336 ret = drbg_hmac_init(drbg);
338 ret = drbg_hash_init(drbg);
343 RANDerr(RAND_F_RAND_DRBG_SET, RAND_R_UNSUPPORTED_DRBG_TYPE);
348 drbg->state = DRBG_ERROR;
349 RANDerr(RAND_F_RAND_DRBG_SET, RAND_R_ERROR_INITIALISING_DRBG);
355 * Set/initialize default |type| and |flag| for new drbg instances.
357 * Returns 1 on success, 0 on failure.
359 int RAND_DRBG_set_defaults(int type, unsigned int flags)
362 if (!(is_digest(type) || is_ctr(type))) {
363 RANDerr(RAND_F_RAND_DRBG_SET_DEFAULTS, RAND_R_UNSUPPORTED_DRBG_TYPE);
367 if ((flags & ~rand_drbg_used_flags) != 0) {
368 RANDerr(RAND_F_RAND_DRBG_SET_DEFAULTS, RAND_R_UNSUPPORTED_DRBG_FLAGS);
372 all = ((flags & RAND_DRBG_TYPE_FLAGS) == 0);
373 if (all || (flags & RAND_DRBG_FLAG_MASTER) != 0) {
374 rand_drbg_type[RAND_DRBG_TYPE_MASTER] = type;
375 rand_drbg_flags[RAND_DRBG_TYPE_MASTER] = flags | RAND_DRBG_FLAG_MASTER;
377 if (all || (flags & RAND_DRBG_FLAG_PUBLIC) != 0) {
378 rand_drbg_type[RAND_DRBG_TYPE_PUBLIC] = type;
379 rand_drbg_flags[RAND_DRBG_TYPE_PUBLIC] = flags | RAND_DRBG_FLAG_PUBLIC;
381 if (all || (flags & RAND_DRBG_FLAG_PRIVATE) != 0) {
382 rand_drbg_type[RAND_DRBG_TYPE_PRIVATE] = type;
383 rand_drbg_flags[RAND_DRBG_TYPE_PRIVATE] = flags | RAND_DRBG_FLAG_PRIVATE;
390 * Allocate memory and initialize a new DRBG. The DRBG is allocated on
391 * the secure heap if |secure| is nonzero and the secure heap is enabled.
392 * The |parent|, if not NULL, will be used as random source for reseeding.
394 * Returns a pointer to the new DRBG instance on success, NULL on failure.
396 static RAND_DRBG *rand_drbg_new(OPENSSL_CTX *ctx,
402 RAND_DRBG *drbg = secure ? OPENSSL_secure_zalloc(sizeof(*drbg))
403 : OPENSSL_zalloc(sizeof(*drbg));
406 RANDerr(RAND_F_RAND_DRBG_NEW, ERR_R_MALLOC_FAILURE);
411 drbg->secure = secure && CRYPTO_secure_allocated(drbg);
412 drbg->fork_count = rand_fork_count;
413 drbg->parent = parent;
415 if (parent == NULL) {
417 drbg->get_entropy = rand_crngt_get_entropy;
418 drbg->cleanup_entropy = rand_crngt_cleanup_entropy;
420 drbg->get_entropy = rand_drbg_get_entropy;
421 drbg->cleanup_entropy = rand_drbg_cleanup_entropy;
423 #ifndef RAND_DRBG_GET_RANDOM_NONCE
424 drbg->get_nonce = rand_drbg_get_nonce;
425 drbg->cleanup_nonce = rand_drbg_cleanup_nonce;
428 drbg->reseed_interval = master_reseed_interval;
429 drbg->reseed_time_interval = master_reseed_time_interval;
431 drbg->get_entropy = rand_drbg_get_entropy;
432 drbg->cleanup_entropy = rand_drbg_cleanup_entropy;
434 * Do not provide nonce callbacks, the child DRBGs will
435 * obtain their nonce using random bits from the parent.
438 drbg->reseed_interval = slave_reseed_interval;
439 drbg->reseed_time_interval = slave_reseed_time_interval;
442 if (RAND_DRBG_set(drbg, type, flags) == 0)
445 if (parent != NULL) {
446 rand_drbg_lock(parent);
447 if (drbg->strength > parent->strength) {
449 * We currently don't support the algorithm from NIST SP 800-90C
450 * 10.1.2 to use a weaker DRBG as source
452 rand_drbg_unlock(parent);
453 RANDerr(RAND_F_RAND_DRBG_NEW, RAND_R_PARENT_STRENGTH_TOO_WEAK);
456 rand_drbg_unlock(parent);
462 RAND_DRBG_free(drbg);
467 RAND_DRBG *RAND_DRBG_new_ex(OPENSSL_CTX *ctx, int type, unsigned int flags,
470 return rand_drbg_new(ctx, 0, type, flags, parent);
473 RAND_DRBG *RAND_DRBG_new(int type, unsigned int flags, RAND_DRBG *parent)
475 return RAND_DRBG_new_ex(NULL, type, flags, parent);
478 RAND_DRBG *RAND_DRBG_secure_new_ex(OPENSSL_CTX *ctx, int type,
479 unsigned int flags, RAND_DRBG *parent)
481 return rand_drbg_new(ctx, 1, type, flags, parent);
484 RAND_DRBG *RAND_DRBG_secure_new(int type, unsigned int flags, RAND_DRBG *parent)
486 return RAND_DRBG_secure_new_ex(NULL, type, flags, parent);
489 * Uninstantiate |drbg| and free all memory.
491 void RAND_DRBG_free(RAND_DRBG *drbg)
496 if (drbg->meth != NULL)
497 drbg->meth->uninstantiate(drbg);
498 rand_pool_free(drbg->adin_pool);
499 CRYPTO_THREAD_lock_free(drbg->lock);
500 CRYPTO_free_ex_data(CRYPTO_EX_INDEX_DRBG, drbg, &drbg->ex_data);
503 OPENSSL_secure_clear_free(drbg, sizeof(*drbg));
505 OPENSSL_clear_free(drbg, sizeof(*drbg));
509 * Instantiate |drbg|, after it has been initialized. Use |pers| and
510 * |perslen| as prediction-resistance input.
512 * Requires that drbg->lock is already locked for write, if non-null.
514 * Returns 1 on success, 0 on failure.
516 int RAND_DRBG_instantiate(RAND_DRBG *drbg,
517 const unsigned char *pers, size_t perslen)
519 unsigned char *nonce = NULL, *entropy = NULL;
520 size_t noncelen = 0, entropylen = 0;
521 size_t min_entropy = drbg->strength;
522 size_t min_entropylen = drbg->min_entropylen;
523 size_t max_entropylen = drbg->max_entropylen;
525 if (perslen > drbg->max_perslen) {
526 RANDerr(RAND_F_RAND_DRBG_INSTANTIATE,
527 RAND_R_PERSONALISATION_STRING_TOO_LONG);
531 if (drbg->meth == NULL) {
532 RANDerr(RAND_F_RAND_DRBG_INSTANTIATE,
533 RAND_R_NO_DRBG_IMPLEMENTATION_SELECTED);
537 if (drbg->state != DRBG_UNINITIALISED) {
538 RANDerr(RAND_F_RAND_DRBG_INSTANTIATE,
539 drbg->state == DRBG_ERROR ? RAND_R_IN_ERROR_STATE
540 : RAND_R_ALREADY_INSTANTIATED);
544 drbg->state = DRBG_ERROR;
547 * NIST SP800-90Ar1 section 9.1 says you can combine getting the entropy
548 * and nonce in 1 call by increasing the entropy with 50% and increasing
549 * the minimum length to accommodate the length of the nonce.
550 * We do this in case a nonce is require and get_nonce is NULL.
552 if (drbg->min_noncelen > 0 && drbg->get_nonce == NULL) {
553 min_entropy += drbg->strength / 2;
554 min_entropylen += drbg->min_noncelen;
555 max_entropylen += drbg->max_noncelen;
558 drbg->reseed_next_counter = tsan_load(&drbg->reseed_prop_counter);
559 if (drbg->reseed_next_counter) {
560 drbg->reseed_next_counter++;
561 if(!drbg->reseed_next_counter)
562 drbg->reseed_next_counter = 1;
565 if (drbg->get_entropy != NULL)
566 entropylen = drbg->get_entropy(drbg, &entropy, min_entropy,
567 min_entropylen, max_entropylen, 0);
568 if (entropylen < min_entropylen
569 || entropylen > max_entropylen) {
570 RANDerr(RAND_F_RAND_DRBG_INSTANTIATE, RAND_R_ERROR_RETRIEVING_ENTROPY);
574 if (drbg->min_noncelen > 0 && drbg->get_nonce != NULL) {
575 noncelen = drbg->get_nonce(drbg, &nonce, drbg->strength / 2,
576 drbg->min_noncelen, drbg->max_noncelen);
577 if (noncelen < drbg->min_noncelen || noncelen > drbg->max_noncelen) {
578 RANDerr(RAND_F_RAND_DRBG_INSTANTIATE, RAND_R_ERROR_RETRIEVING_NONCE);
583 if (!drbg->meth->instantiate(drbg, entropy, entropylen,
584 nonce, noncelen, pers, perslen)) {
585 RANDerr(RAND_F_RAND_DRBG_INSTANTIATE, RAND_R_ERROR_INSTANTIATING_DRBG);
589 drbg->state = DRBG_READY;
590 drbg->reseed_gen_counter = 1;
591 drbg->reseed_time = time(NULL);
592 tsan_store(&drbg->reseed_prop_counter, drbg->reseed_next_counter);
595 if (entropy != NULL && drbg->cleanup_entropy != NULL)
596 drbg->cleanup_entropy(drbg, entropy, entropylen);
597 if (nonce != NULL && drbg->cleanup_nonce != NULL)
598 drbg->cleanup_nonce(drbg, nonce, noncelen);
599 if (drbg->state == DRBG_READY)
605 * Uninstantiate |drbg|. Must be instantiated before it can be used.
607 * Requires that drbg->lock is already locked for write, if non-null.
609 * Returns 1 on success, 0 on failure.
611 int RAND_DRBG_uninstantiate(RAND_DRBG *drbg)
613 int index = -1, type, flags;
614 if (drbg->meth == NULL) {
615 drbg->state = DRBG_ERROR;
616 RANDerr(RAND_F_RAND_DRBG_UNINSTANTIATE,
617 RAND_R_NO_DRBG_IMPLEMENTATION_SELECTED);
621 /* Clear the entire drbg->ctr struct, then reset some important
622 * members of the drbg->ctr struct (e.g. keysize, df_ks) to their
625 drbg->meth->uninstantiate(drbg);
627 /* The reset uses the default values for type and flags */
628 if (drbg->flags & RAND_DRBG_FLAG_MASTER)
629 index = RAND_DRBG_TYPE_MASTER;
630 else if (drbg->flags & RAND_DRBG_FLAG_PRIVATE)
631 index = RAND_DRBG_TYPE_PRIVATE;
632 else if (drbg->flags & RAND_DRBG_FLAG_PUBLIC)
633 index = RAND_DRBG_TYPE_PUBLIC;
636 flags = rand_drbg_flags[index];
637 type = rand_drbg_type[index];
642 return RAND_DRBG_set(drbg, type, flags);
646 * Reseed |drbg|, mixing in the specified data
648 * Requires that drbg->lock is already locked for write, if non-null.
650 * Returns 1 on success, 0 on failure.
652 int RAND_DRBG_reseed(RAND_DRBG *drbg,
653 const unsigned char *adin, size_t adinlen,
654 int prediction_resistance)
656 unsigned char *entropy = NULL;
657 size_t entropylen = 0;
659 if (drbg->state == DRBG_ERROR) {
660 RANDerr(RAND_F_RAND_DRBG_RESEED, RAND_R_IN_ERROR_STATE);
663 if (drbg->state == DRBG_UNINITIALISED) {
664 RANDerr(RAND_F_RAND_DRBG_RESEED, RAND_R_NOT_INSTANTIATED);
670 } else if (adinlen > drbg->max_adinlen) {
671 RANDerr(RAND_F_RAND_DRBG_RESEED, RAND_R_ADDITIONAL_INPUT_TOO_LONG);
675 drbg->state = DRBG_ERROR;
677 drbg->reseed_next_counter = tsan_load(&drbg->reseed_prop_counter);
678 if (drbg->reseed_next_counter) {
679 drbg->reseed_next_counter++;
680 if(!drbg->reseed_next_counter)
681 drbg->reseed_next_counter = 1;
684 if (drbg->get_entropy != NULL)
685 entropylen = drbg->get_entropy(drbg, &entropy, drbg->strength,
686 drbg->min_entropylen,
687 drbg->max_entropylen,
688 prediction_resistance);
689 if (entropylen < drbg->min_entropylen
690 || entropylen > drbg->max_entropylen) {
691 RANDerr(RAND_F_RAND_DRBG_RESEED, RAND_R_ERROR_RETRIEVING_ENTROPY);
695 if (!drbg->meth->reseed(drbg, entropy, entropylen, adin, adinlen))
698 drbg->state = DRBG_READY;
699 drbg->reseed_gen_counter = 1;
700 drbg->reseed_time = time(NULL);
701 tsan_store(&drbg->reseed_prop_counter, drbg->reseed_next_counter);
704 if (entropy != NULL && drbg->cleanup_entropy != NULL)
705 drbg->cleanup_entropy(drbg, entropy, entropylen);
706 if (drbg->state == DRBG_READY)
712 * Restart |drbg|, using the specified entropy or additional input
714 * Tries its best to get the drbg instantiated by all means,
715 * regardless of its current state.
717 * Optionally, a |buffer| of |len| random bytes can be passed,
718 * which is assumed to contain at least |entropy| bits of entropy.
720 * If |entropy| > 0, the buffer content is used as entropy input.
722 * If |entropy| == 0, the buffer content is used as additional input
724 * Returns 1 on success, 0 on failure.
726 * This function is used internally only.
728 int rand_drbg_restart(RAND_DRBG *drbg,
729 const unsigned char *buffer, size_t len, size_t entropy)
732 const unsigned char *adin = NULL;
735 if (drbg->seed_pool != NULL) {
736 RANDerr(RAND_F_RAND_DRBG_RESTART, ERR_R_INTERNAL_ERROR);
737 drbg->state = DRBG_ERROR;
738 rand_pool_free(drbg->seed_pool);
739 drbg->seed_pool = NULL;
743 if (buffer != NULL) {
745 if (drbg->max_entropylen < len) {
746 RANDerr(RAND_F_RAND_DRBG_RESTART,
747 RAND_R_ENTROPY_INPUT_TOO_LONG);
748 drbg->state = DRBG_ERROR;
752 if (entropy > 8 * len) {
753 RANDerr(RAND_F_RAND_DRBG_RESTART, RAND_R_ENTROPY_OUT_OF_RANGE);
754 drbg->state = DRBG_ERROR;
758 /* will be picked up by the rand_drbg_get_entropy() callback */
759 drbg->seed_pool = rand_pool_attach(buffer, len, entropy);
760 if (drbg->seed_pool == NULL)
763 if (drbg->max_adinlen < len) {
764 RANDerr(RAND_F_RAND_DRBG_RESTART,
765 RAND_R_ADDITIONAL_INPUT_TOO_LONG);
766 drbg->state = DRBG_ERROR;
774 /* repair error state */
775 if (drbg->state == DRBG_ERROR)
776 RAND_DRBG_uninstantiate(drbg);
778 /* repair uninitialized state */
779 if (drbg->state == DRBG_UNINITIALISED) {
780 /* reinstantiate drbg */
781 RAND_DRBG_instantiate(drbg,
782 (const unsigned char *) ossl_pers_string,
783 sizeof(ossl_pers_string) - 1);
784 /* already reseeded. prevent second reseeding below */
785 reseeded = (drbg->state == DRBG_READY);
788 /* refresh current state if entropy or additional input has been provided */
789 if (drbg->state == DRBG_READY) {
792 * mix in additional input without reseeding
794 * Similar to RAND_DRBG_reseed(), but the provided additional
795 * data |adin| is mixed into the current state without pulling
796 * entropy from the trusted entropy source using get_entropy().
797 * This is not a reseeding in the strict sense of NIST SP 800-90A.
799 drbg->meth->reseed(drbg, adin, adinlen, NULL, 0);
800 } else if (reseeded == 0) {
801 /* do a full reseeding if it has not been done yet above */
802 RAND_DRBG_reseed(drbg, NULL, 0, 0);
806 rand_pool_free(drbg->seed_pool);
807 drbg->seed_pool = NULL;
809 return drbg->state == DRBG_READY;
813 * Generate |outlen| bytes into the buffer at |out|. Reseed if we need
814 * to or if |prediction_resistance| is set. Additional input can be
815 * sent in |adin| and |adinlen|.
817 * Requires that drbg->lock is already locked for write, if non-null.
819 * Returns 1 on success, 0 on failure.
822 int RAND_DRBG_generate(RAND_DRBG *drbg, unsigned char *out, size_t outlen,
823 int prediction_resistance,
824 const unsigned char *adin, size_t adinlen)
826 int reseed_required = 0;
828 if (drbg->state != DRBG_READY) {
829 /* try to recover from previous errors */
830 rand_drbg_restart(drbg, NULL, 0, 0);
832 if (drbg->state == DRBG_ERROR) {
833 RANDerr(RAND_F_RAND_DRBG_GENERATE, RAND_R_IN_ERROR_STATE);
836 if (drbg->state == DRBG_UNINITIALISED) {
837 RANDerr(RAND_F_RAND_DRBG_GENERATE, RAND_R_NOT_INSTANTIATED);
842 if (outlen > drbg->max_request) {
843 RANDerr(RAND_F_RAND_DRBG_GENERATE, RAND_R_REQUEST_TOO_LARGE_FOR_DRBG);
846 if (adinlen > drbg->max_adinlen) {
847 RANDerr(RAND_F_RAND_DRBG_GENERATE, RAND_R_ADDITIONAL_INPUT_TOO_LONG);
851 if (drbg->fork_count != rand_fork_count) {
852 drbg->fork_count = rand_fork_count;
856 if (drbg->reseed_interval > 0) {
857 if (drbg->reseed_gen_counter > drbg->reseed_interval)
860 if (drbg->reseed_time_interval > 0) {
861 time_t now = time(NULL);
862 if (now < drbg->reseed_time
863 || now - drbg->reseed_time >= drbg->reseed_time_interval)
866 if (drbg->parent != NULL) {
867 unsigned int reseed_counter = tsan_load(&drbg->reseed_prop_counter);
868 if (reseed_counter > 0
869 && tsan_load(&drbg->parent->reseed_prop_counter)
874 if (reseed_required || prediction_resistance) {
875 if (!RAND_DRBG_reseed(drbg, adin, adinlen, prediction_resistance)) {
876 RANDerr(RAND_F_RAND_DRBG_GENERATE, RAND_R_RESEED_ERROR);
883 if (!drbg->meth->generate(drbg, out, outlen, adin, adinlen)) {
884 drbg->state = DRBG_ERROR;
885 RANDerr(RAND_F_RAND_DRBG_GENERATE, RAND_R_GENERATE_ERROR);
889 drbg->reseed_gen_counter++;
895 * Generates |outlen| random bytes and stores them in |out|. It will
896 * using the given |drbg| to generate the bytes.
898 * Requires that drbg->lock is already locked for write, if non-null.
900 * Returns 1 on success 0 on failure.
902 int RAND_DRBG_bytes(RAND_DRBG *drbg, unsigned char *out, size_t outlen)
904 unsigned char *additional = NULL;
905 size_t additional_len;
909 if (drbg->adin_pool == NULL) {
912 drbg->adin_pool = rand_pool_new(0, 0, 0, drbg->max_adinlen);
913 if (drbg->adin_pool == NULL)
917 additional_len = rand_drbg_get_additional_data(drbg->adin_pool,
920 for ( ; outlen > 0; outlen -= chunk, out += chunk) {
922 if (chunk > drbg->max_request)
923 chunk = drbg->max_request;
924 ret = RAND_DRBG_generate(drbg, out, chunk, 0, additional, additional_len);
931 if (additional != NULL)
932 rand_drbg_cleanup_additional_data(drbg->adin_pool, additional);
938 * Set the RAND_DRBG callbacks for obtaining entropy and nonce.
940 * Setting the callbacks is allowed only if the drbg has not been
941 * initialized yet. Otherwise, the operation will fail.
943 * Returns 1 on success, 0 on failure.
945 int RAND_DRBG_set_callbacks(RAND_DRBG *drbg,
946 RAND_DRBG_get_entropy_fn get_entropy,
947 RAND_DRBG_cleanup_entropy_fn cleanup_entropy,
948 RAND_DRBG_get_nonce_fn get_nonce,
949 RAND_DRBG_cleanup_nonce_fn cleanup_nonce)
951 if (drbg->state != DRBG_UNINITIALISED
952 || drbg->parent != NULL)
954 drbg->get_entropy = get_entropy;
955 drbg->cleanup_entropy = cleanup_entropy;
956 drbg->get_nonce = get_nonce;
957 drbg->cleanup_nonce = cleanup_nonce;
962 * Set the reseed interval.
964 * The drbg will reseed automatically whenever the number of generate
965 * requests exceeds the given reseed interval. If the reseed interval
966 * is 0, then this feature is disabled.
968 * Returns 1 on success, 0 on failure.
970 int RAND_DRBG_set_reseed_interval(RAND_DRBG *drbg, unsigned int interval)
972 if (interval > MAX_RESEED_INTERVAL)
974 drbg->reseed_interval = interval;
979 * Set the reseed time interval.
981 * The drbg will reseed automatically whenever the time elapsed since
982 * the last reseeding exceeds the given reseed time interval. For safety,
983 * a reseeding will also occur if the clock has been reset to a smaller
986 * Returns 1 on success, 0 on failure.
988 int RAND_DRBG_set_reseed_time_interval(RAND_DRBG *drbg, time_t interval)
990 if (interval > MAX_RESEED_TIME_INTERVAL)
992 drbg->reseed_time_interval = interval;
997 * Set the default values for reseed (time) intervals of new DRBG instances
999 * The default values can be set independently for master DRBG instances
1000 * (without a parent) and slave DRBG instances (with parent).
1002 * Returns 1 on success, 0 on failure.
1005 int RAND_DRBG_set_reseed_defaults(
1006 unsigned int _master_reseed_interval,
1007 unsigned int _slave_reseed_interval,
1008 time_t _master_reseed_time_interval,
1009 time_t _slave_reseed_time_interval
1012 if (_master_reseed_interval > MAX_RESEED_INTERVAL
1013 || _slave_reseed_interval > MAX_RESEED_INTERVAL)
1016 if (_master_reseed_time_interval > MAX_RESEED_TIME_INTERVAL
1017 || _slave_reseed_time_interval > MAX_RESEED_TIME_INTERVAL)
1020 master_reseed_interval = _master_reseed_interval;
1021 slave_reseed_interval = _slave_reseed_interval;
1023 master_reseed_time_interval = _master_reseed_time_interval;
1024 slave_reseed_time_interval = _slave_reseed_time_interval;
1030 * Locks the given drbg. Locking a drbg which does not have locking
1031 * enabled is considered a successful no-op.
1033 * Returns 1 on success, 0 on failure.
1035 int rand_drbg_lock(RAND_DRBG *drbg)
1037 if (drbg->lock != NULL)
1038 return CRYPTO_THREAD_write_lock(drbg->lock);
1044 * Unlocks the given drbg. Unlocking a drbg which does not have locking
1045 * enabled is considered a successful no-op.
1047 * Returns 1 on success, 0 on failure.
1049 int rand_drbg_unlock(RAND_DRBG *drbg)
1051 if (drbg->lock != NULL)
1052 return CRYPTO_THREAD_unlock(drbg->lock);
1058 * Enables locking for the given drbg
1060 * Locking can only be enabled if the random generator
1061 * is in the uninitialized state.
1063 * Returns 1 on success, 0 on failure.
1065 int rand_drbg_enable_locking(RAND_DRBG *drbg)
1067 if (drbg->state != DRBG_UNINITIALISED) {
1068 RANDerr(RAND_F_RAND_DRBG_ENABLE_LOCKING,
1069 RAND_R_DRBG_ALREADY_INITIALIZED);
1073 if (drbg->lock == NULL) {
1074 if (drbg->parent != NULL && drbg->parent->lock == NULL) {
1075 RANDerr(RAND_F_RAND_DRBG_ENABLE_LOCKING,
1076 RAND_R_PARENT_LOCKING_NOT_ENABLED);
1080 drbg->lock = CRYPTO_THREAD_lock_new();
1081 if (drbg->lock == NULL) {
1082 RANDerr(RAND_F_RAND_DRBG_ENABLE_LOCKING,
1083 RAND_R_FAILED_TO_CREATE_LOCK);
1092 * Get and set the EXDATA
1094 int RAND_DRBG_set_ex_data(RAND_DRBG *drbg, int idx, void *arg)
1096 return CRYPTO_set_ex_data(&drbg->ex_data, idx, arg);
1099 void *RAND_DRBG_get_ex_data(const RAND_DRBG *drbg, int idx)
1101 return CRYPTO_get_ex_data(&drbg->ex_data, idx);
1106 * The following functions provide a RAND_METHOD that works on the
1107 * global DRBG. They lock.
1111 * Allocates a new global DRBG on the secure heap (if enabled) and
1112 * initializes it with default settings.
1114 * Returns a pointer to the new DRBG instance on success, NULL on failure.
1116 static RAND_DRBG *drbg_setup(OPENSSL_CTX *ctx, RAND_DRBG *parent, int drbg_type)
1120 drbg = RAND_DRBG_secure_new_ex(ctx, rand_drbg_type[drbg_type],
1121 rand_drbg_flags[drbg_type], parent);
1125 /* Only the master DRBG needs to have a lock */
1126 if (parent == NULL && rand_drbg_enable_locking(drbg) == 0)
1129 /* enable seed propagation */
1130 tsan_store(&drbg->reseed_prop_counter, 1);
1133 * Ignore instantiation error to support just-in-time instantiation.
1135 * The state of the drbg will be checked in RAND_DRBG_generate() and
1136 * an automatic recovery is attempted.
1138 (void)RAND_DRBG_instantiate(drbg,
1139 (const unsigned char *) ossl_pers_string,
1140 sizeof(ossl_pers_string) - 1);
1144 RAND_DRBG_free(drbg);
1148 static void drbg_delete_thread_state(void *arg)
1150 OPENSSL_CTX *ctx = arg;
1151 DRBG_GLOBAL *dgbl = drbg_get_global(ctx);
1156 drbg = CRYPTO_THREAD_get_local(&dgbl->public_drbg);
1157 CRYPTO_THREAD_set_local(&dgbl->public_drbg, NULL);
1158 RAND_DRBG_free(drbg);
1160 drbg = CRYPTO_THREAD_get_local(&dgbl->private_drbg);
1161 CRYPTO_THREAD_set_local(&dgbl->private_drbg, NULL);
1162 RAND_DRBG_free(drbg);
1165 /* Implements the default OpenSSL RAND_bytes() method */
1166 static int drbg_bytes(unsigned char *out, int count)
1169 RAND_DRBG *drbg = RAND_DRBG_get0_public();
1174 ret = RAND_DRBG_bytes(drbg, out, count);
1180 * Calculates the minimum length of a full entropy buffer
1181 * which is necessary to seed (i.e. instantiate) the DRBG
1184 size_t rand_drbg_seedlen(RAND_DRBG *drbg)
1187 * If no os entropy source is available then RAND_seed(buffer, bufsize)
1188 * is expected to succeed if and only if the buffer length satisfies
1189 * the following requirements, which follow from the calculations
1190 * in RAND_DRBG_instantiate().
1192 size_t min_entropy = drbg->strength;
1193 size_t min_entropylen = drbg->min_entropylen;
1196 * Extra entropy for the random nonce in the absence of a
1197 * get_nonce callback, see comment in RAND_DRBG_instantiate().
1199 if (drbg->min_noncelen > 0 && drbg->get_nonce == NULL) {
1200 min_entropy += drbg->strength / 2;
1201 min_entropylen += drbg->min_noncelen;
1205 * Convert entropy requirement from bits to bytes
1206 * (dividing by 8 without rounding upwards, because
1207 * all entropy requirements are divisible by 8).
1211 /* Return a value that satisfies both requirements */
1212 return min_entropy > min_entropylen ? min_entropy : min_entropylen;
1215 /* Implements the default OpenSSL RAND_add() method */
1216 static int drbg_add(const void *buf, int num, double randomness)
1219 RAND_DRBG *drbg = RAND_DRBG_get0_master();
1226 if (num < 0 || randomness < 0.0)
1229 rand_drbg_lock(drbg);
1230 seedlen = rand_drbg_seedlen(drbg);
1232 buflen = (size_t)num;
1236 * NIST SP-800-90A mandates that entropy *shall not* be provided
1237 * by the consuming application. By setting the randomness to zero,
1238 * we ensure that the buffer contents will be added to the internal
1239 * state of the DRBG only as additional data.
1241 * (NIST SP-800-90Ar1, Sections 9.1 and 9.2)
1245 if (buflen < seedlen || randomness < (double) seedlen) {
1246 #if defined(OPENSSL_RAND_SEED_NONE)
1248 * If no os entropy source is available, a reseeding will fail
1249 * inevitably. So we use a trick to mix the buffer contents into
1250 * the DRBG state without forcing a reseeding: we generate a
1251 * dummy random byte, using the buffer content as additional data.
1252 * Note: This won't work with RAND_DRBG_FLAG_CTR_NO_DF.
1254 unsigned char dummy[1];
1256 ret = RAND_DRBG_generate(drbg, dummy, sizeof(dummy), 0, buf, buflen);
1257 rand_drbg_unlock(drbg);
1261 * If an os entropy source is available then we declare the buffer content
1262 * as additional data by setting randomness to zero and trigger a regular
1269 if (randomness > (double)seedlen) {
1271 * The purpose of this check is to bound |randomness| by a
1272 * relatively small value in order to prevent an integer
1273 * overflow when multiplying by 8 in the rand_drbg_restart()
1274 * call below. Note that randomness is measured in bytes,
1275 * not bits, so this value corresponds to eight times the
1276 * security strength.
1278 randomness = (double)seedlen;
1281 ret = rand_drbg_restart(drbg, buf, buflen, (size_t)(8 * randomness));
1282 rand_drbg_unlock(drbg);
1287 /* Implements the default OpenSSL RAND_seed() method */
1288 static int drbg_seed(const void *buf, int num)
1290 return drbg_add(buf, num, num);
1293 /* Implements the default OpenSSL RAND_status() method */
1294 static int drbg_status(void)
1297 RAND_DRBG *drbg = RAND_DRBG_get0_master();
1302 rand_drbg_lock(drbg);
1303 ret = drbg->state == DRBG_READY ? 1 : 0;
1304 rand_drbg_unlock(drbg);
1309 * Get the master DRBG.
1310 * Returns pointer to the DRBG on success, NULL on failure.
1313 RAND_DRBG *OPENSSL_CTX_get0_master_drbg(OPENSSL_CTX *ctx)
1315 DRBG_GLOBAL *dgbl = drbg_get_global(ctx);
1320 return dgbl->master_drbg;
1323 RAND_DRBG *RAND_DRBG_get0_master(void)
1325 return OPENSSL_CTX_get0_master_drbg(NULL);
1329 * Get the public DRBG.
1330 * Returns pointer to the DRBG on success, NULL on failure.
1332 RAND_DRBG *OPENSSL_CTX_get0_public_drbg(OPENSSL_CTX *ctx)
1334 DRBG_GLOBAL *dgbl = drbg_get_global(ctx);
1340 drbg = CRYPTO_THREAD_get_local(&dgbl->public_drbg);
1342 ctx = openssl_ctx_get_concrete(ctx);
1343 if (!ossl_init_thread_start(NULL, ctx, drbg_delete_thread_state))
1345 drbg = drbg_setup(ctx, dgbl->master_drbg, RAND_DRBG_TYPE_PUBLIC);
1346 CRYPTO_THREAD_set_local(&dgbl->public_drbg, drbg);
1351 RAND_DRBG *RAND_DRBG_get0_public(void)
1353 return OPENSSL_CTX_get0_public_drbg(NULL);
1357 * Get the private DRBG.
1358 * Returns pointer to the DRBG on success, NULL on failure.
1360 RAND_DRBG *OPENSSL_CTX_get0_private_drbg(OPENSSL_CTX *ctx)
1362 DRBG_GLOBAL *dgbl = drbg_get_global(ctx);
1368 drbg = CRYPTO_THREAD_get_local(&dgbl->private_drbg);
1370 ctx = openssl_ctx_get_concrete(ctx);
1371 if (!ossl_init_thread_start(NULL, ctx, drbg_delete_thread_state))
1373 drbg = drbg_setup(ctx, dgbl->master_drbg, RAND_DRBG_TYPE_PRIVATE);
1374 CRYPTO_THREAD_set_local(&dgbl->private_drbg, drbg);
1379 RAND_DRBG *RAND_DRBG_get0_private(void)
1381 return OPENSSL_CTX_get0_private_drbg(NULL);
1384 RAND_METHOD rand_meth = {
1393 RAND_METHOD *RAND_OpenSSL(void)