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>
14 #include "rand_local.h"
15 #include "internal/thread_once.h"
16 #include "crypto/rand.h"
17 #include "crypto/cryptlib.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;
197 RAND_DRBG_free(dgbl->master_drbg);
198 CRYPTO_THREAD_cleanup_local(&dgbl->private_drbg);
199 CRYPTO_THREAD_cleanup_local(&dgbl->public_drbg);
204 static const OPENSSL_CTX_METHOD drbg_ossl_ctx_method = {
210 * drbg_ossl_ctx_new() calls drgb_setup() which calls rand_drbg_get_nonce()
211 * which needs to get the rand_nonce_lock out of the OPENSSL_CTX...but since
212 * drbg_ossl_ctx_new() hasn't finished running yet we need the rand_nonce_lock
213 * to be in a different global data object. Otherwise we will go into an
214 * infinite recursion loop.
216 static void *drbg_nonce_ossl_ctx_new(OPENSSL_CTX *libctx)
218 DRBG_NONCE_GLOBAL *dngbl = OPENSSL_zalloc(sizeof(*dngbl));
223 dngbl->rand_nonce_lock = CRYPTO_THREAD_lock_new();
224 if (dngbl->rand_nonce_lock == NULL) {
232 static void drbg_nonce_ossl_ctx_free(void *vdngbl)
234 DRBG_NONCE_GLOBAL *dngbl = vdngbl;
239 CRYPTO_THREAD_lock_free(dngbl->rand_nonce_lock);
244 static const OPENSSL_CTX_METHOD drbg_nonce_ossl_ctx_method = {
245 drbg_nonce_ossl_ctx_new,
246 drbg_nonce_ossl_ctx_free,
249 static DRBG_GLOBAL *drbg_get_global(OPENSSL_CTX *libctx)
251 return openssl_ctx_get_data(libctx, OPENSSL_CTX_DRBG_INDEX,
252 &drbg_ossl_ctx_method);
255 /* Implements the get_nonce() callback (see RAND_DRBG_set_callbacks()) */
256 size_t rand_drbg_get_nonce(RAND_DRBG *drbg,
257 unsigned char **pout,
258 int entropy, size_t min_len, size_t max_len)
262 DRBG_NONCE_GLOBAL *dngbl
263 = openssl_ctx_get_data(drbg->libctx, OPENSSL_CTX_DRBG_NONCE_INDEX,
264 &drbg_nonce_ossl_ctx_method);
273 memset(&data, 0, sizeof(data));
274 pool = rand_pool_new(0, 0, min_len, max_len);
278 if (rand_pool_add_nonce_data(pool) == 0)
281 data.instance = drbg;
282 CRYPTO_atomic_add(&dngbl->rand_nonce_count, 1, &data.count,
283 dngbl->rand_nonce_lock);
285 if (rand_pool_add(pool, (unsigned char *)&data, sizeof(data), 0) == 0)
288 ret = rand_pool_length(pool);
289 *pout = rand_pool_detach(pool);
292 rand_pool_free(pool);
298 * Implements the cleanup_nonce() callback (see RAND_DRBG_set_callbacks())
301 void rand_drbg_cleanup_nonce(RAND_DRBG *drbg,
302 unsigned char *out, size_t outlen)
304 OPENSSL_clear_free(out, outlen);
308 * Set the |drbg|'s callback data pointer for the entropy and nonce callbacks
310 * The ownership of the context data remains with the caller,
311 * i.e., it is the caller's responsibility to keep it available as long
312 * as it is need by the callbacks and free it after use.
314 * Setting the callback data is allowed only if the drbg has not been
315 * initialized yet. Otherwise, the operation will fail.
317 * Returns 1 on success, 0 on failure.
319 int RAND_DRBG_set_callback_data(RAND_DRBG *drbg, void *data)
321 if (drbg->state != DRBG_UNINITIALISED
322 || drbg->parent != NULL)
325 drbg->callback_data = data;
329 /* Retrieve the callback data pointer */
330 void *RAND_DRBG_get_callback_data(RAND_DRBG *drbg)
332 return drbg->callback_data;
336 * Set/initialize |drbg| to be of type |type|, with optional |flags|.
338 * If |type| and |flags| are zero, use the defaults
340 * Returns 1 on success, 0 on failure.
342 int RAND_DRBG_set(RAND_DRBG *drbg, int type, unsigned int flags)
346 if (type == 0 && flags == 0) {
347 type = rand_drbg_type[RAND_DRBG_TYPE_MASTER];
348 flags = rand_drbg_flags[RAND_DRBG_TYPE_MASTER];
351 /* If set is called multiple times - clear the old one */
352 if (drbg->type != 0 && (type != drbg->type || flags != drbg->flags)) {
353 drbg->meth->uninstantiate(drbg);
354 rand_pool_free(drbg->adin_pool);
355 drbg->adin_pool = NULL;
358 drbg->state = DRBG_UNINITIALISED;
363 /* Uninitialized; that's okay. */
366 } else if (is_ctr(type)) {
367 ret = drbg_ctr_init(drbg);
368 } else if (is_digest(type)) {
369 if (flags & RAND_DRBG_FLAG_HMAC)
370 ret = drbg_hmac_init(drbg);
372 ret = drbg_hash_init(drbg);
377 RANDerr(RAND_F_RAND_DRBG_SET, RAND_R_UNSUPPORTED_DRBG_TYPE);
382 drbg->state = DRBG_ERROR;
383 RANDerr(RAND_F_RAND_DRBG_SET, RAND_R_ERROR_INITIALISING_DRBG);
389 * Set/initialize default |type| and |flag| for new drbg instances.
391 * Returns 1 on success, 0 on failure.
393 int RAND_DRBG_set_defaults(int type, unsigned int flags)
396 if (!(is_digest(type) || is_ctr(type))) {
397 RANDerr(RAND_F_RAND_DRBG_SET_DEFAULTS, RAND_R_UNSUPPORTED_DRBG_TYPE);
401 if ((flags & ~rand_drbg_used_flags) != 0) {
402 RANDerr(RAND_F_RAND_DRBG_SET_DEFAULTS, RAND_R_UNSUPPORTED_DRBG_FLAGS);
406 all = ((flags & RAND_DRBG_TYPE_FLAGS) == 0);
407 if (all || (flags & RAND_DRBG_FLAG_MASTER) != 0) {
408 rand_drbg_type[RAND_DRBG_TYPE_MASTER] = type;
409 rand_drbg_flags[RAND_DRBG_TYPE_MASTER] = flags | RAND_DRBG_FLAG_MASTER;
411 if (all || (flags & RAND_DRBG_FLAG_PUBLIC) != 0) {
412 rand_drbg_type[RAND_DRBG_TYPE_PUBLIC] = type;
413 rand_drbg_flags[RAND_DRBG_TYPE_PUBLIC] = flags | RAND_DRBG_FLAG_PUBLIC;
415 if (all || (flags & RAND_DRBG_FLAG_PRIVATE) != 0) {
416 rand_drbg_type[RAND_DRBG_TYPE_PRIVATE] = type;
417 rand_drbg_flags[RAND_DRBG_TYPE_PRIVATE] = flags | RAND_DRBG_FLAG_PRIVATE;
424 * Allocate memory and initialize a new DRBG. The DRBG is allocated on
425 * the secure heap if |secure| is nonzero and the secure heap is enabled.
426 * The |parent|, if not NULL, will be used as random source for reseeding.
428 * Returns a pointer to the new DRBG instance on success, NULL on failure.
430 static RAND_DRBG *rand_drbg_new(OPENSSL_CTX *ctx,
436 RAND_DRBG *drbg = secure ? OPENSSL_secure_zalloc(sizeof(*drbg))
437 : OPENSSL_zalloc(sizeof(*drbg));
440 RANDerr(RAND_F_RAND_DRBG_NEW, ERR_R_MALLOC_FAILURE);
445 drbg->secure = secure && CRYPTO_secure_allocated(drbg);
446 drbg->fork_id = openssl_get_fork_id();
447 drbg->parent = parent;
449 if (parent == NULL) {
451 drbg->get_entropy = rand_crngt_get_entropy;
452 drbg->cleanup_entropy = rand_crngt_cleanup_entropy;
454 drbg->get_entropy = rand_drbg_get_entropy;
455 drbg->cleanup_entropy = rand_drbg_cleanup_entropy;
457 #ifndef RAND_DRBG_GET_RANDOM_NONCE
458 drbg->get_nonce = rand_drbg_get_nonce;
459 drbg->cleanup_nonce = rand_drbg_cleanup_nonce;
462 drbg->reseed_interval = master_reseed_interval;
463 drbg->reseed_time_interval = master_reseed_time_interval;
465 drbg->get_entropy = rand_drbg_get_entropy;
466 drbg->cleanup_entropy = rand_drbg_cleanup_entropy;
468 * Do not provide nonce callbacks, the child DRBGs will
469 * obtain their nonce using random bits from the parent.
472 drbg->reseed_interval = slave_reseed_interval;
473 drbg->reseed_time_interval = slave_reseed_time_interval;
476 if (RAND_DRBG_set(drbg, type, flags) == 0)
479 if (parent != NULL) {
480 rand_drbg_lock(parent);
481 if (drbg->strength > parent->strength) {
483 * We currently don't support the algorithm from NIST SP 800-90C
484 * 10.1.2 to use a weaker DRBG as source
486 rand_drbg_unlock(parent);
487 RANDerr(RAND_F_RAND_DRBG_NEW, RAND_R_PARENT_STRENGTH_TOO_WEAK);
490 rand_drbg_unlock(parent);
496 RAND_DRBG_free(drbg);
501 RAND_DRBG *RAND_DRBG_new_ex(OPENSSL_CTX *ctx, int type, unsigned int flags,
504 return rand_drbg_new(ctx, 0, type, flags, parent);
507 RAND_DRBG *RAND_DRBG_new(int type, unsigned int flags, RAND_DRBG *parent)
509 return RAND_DRBG_new_ex(NULL, type, flags, parent);
512 RAND_DRBG *RAND_DRBG_secure_new_ex(OPENSSL_CTX *ctx, int type,
513 unsigned int flags, RAND_DRBG *parent)
515 return rand_drbg_new(ctx, 1, type, flags, parent);
518 RAND_DRBG *RAND_DRBG_secure_new(int type, unsigned int flags, RAND_DRBG *parent)
520 return RAND_DRBG_secure_new_ex(NULL, type, flags, parent);
523 * Uninstantiate |drbg| and free all memory.
525 void RAND_DRBG_free(RAND_DRBG *drbg)
530 if (drbg->meth != NULL)
531 drbg->meth->uninstantiate(drbg);
532 rand_pool_free(drbg->adin_pool);
533 CRYPTO_THREAD_lock_free(drbg->lock);
535 CRYPTO_free_ex_data(CRYPTO_EX_INDEX_RAND_DRBG, drbg, &drbg->ex_data);
539 OPENSSL_secure_clear_free(drbg, sizeof(*drbg));
541 OPENSSL_clear_free(drbg, sizeof(*drbg));
545 * Instantiate |drbg|, after it has been initialized. Use |pers| and
546 * |perslen| as prediction-resistance input.
548 * Requires that drbg->lock is already locked for write, if non-null.
550 * Returns 1 on success, 0 on failure.
552 int RAND_DRBG_instantiate(RAND_DRBG *drbg,
553 const unsigned char *pers, size_t perslen)
555 unsigned char *nonce = NULL, *entropy = NULL;
556 size_t noncelen = 0, entropylen = 0;
557 size_t min_entropy = drbg->strength;
558 size_t min_entropylen = drbg->min_entropylen;
559 size_t max_entropylen = drbg->max_entropylen;
561 if (perslen > drbg->max_perslen) {
562 RANDerr(RAND_F_RAND_DRBG_INSTANTIATE,
563 RAND_R_PERSONALISATION_STRING_TOO_LONG);
567 if (drbg->meth == NULL) {
568 RANDerr(RAND_F_RAND_DRBG_INSTANTIATE,
569 RAND_R_NO_DRBG_IMPLEMENTATION_SELECTED);
573 if (drbg->state != DRBG_UNINITIALISED) {
574 if (drbg->state == DRBG_ERROR)
575 RANDerr(RAND_F_RAND_DRBG_INSTANTIATE, RAND_R_IN_ERROR_STATE);
577 RANDerr(RAND_F_RAND_DRBG_INSTANTIATE, RAND_R_ALREADY_INSTANTIATED);
581 drbg->state = DRBG_ERROR;
584 * NIST SP800-90Ar1 section 9.1 says you can combine getting the entropy
585 * and nonce in 1 call by increasing the entropy with 50% and increasing
586 * the minimum length to accommodate the length of the nonce.
587 * We do this in case a nonce is require and get_nonce is NULL.
589 if (drbg->min_noncelen > 0 && drbg->get_nonce == NULL) {
590 min_entropy += drbg->strength / 2;
591 min_entropylen += drbg->min_noncelen;
592 max_entropylen += drbg->max_noncelen;
595 drbg->reseed_next_counter = tsan_load(&drbg->reseed_prop_counter);
596 if (drbg->reseed_next_counter) {
597 drbg->reseed_next_counter++;
598 if(!drbg->reseed_next_counter)
599 drbg->reseed_next_counter = 1;
602 if (drbg->get_entropy != NULL)
603 entropylen = drbg->get_entropy(drbg, &entropy, min_entropy,
604 min_entropylen, max_entropylen, 0);
605 if (entropylen < min_entropylen
606 || entropylen > max_entropylen) {
607 RANDerr(RAND_F_RAND_DRBG_INSTANTIATE, RAND_R_ERROR_RETRIEVING_ENTROPY);
611 if (drbg->min_noncelen > 0 && drbg->get_nonce != NULL) {
612 noncelen = drbg->get_nonce(drbg, &nonce, drbg->strength / 2,
613 drbg->min_noncelen, drbg->max_noncelen);
614 if (noncelen < drbg->min_noncelen || noncelen > drbg->max_noncelen) {
615 RANDerr(RAND_F_RAND_DRBG_INSTANTIATE, RAND_R_ERROR_RETRIEVING_NONCE);
620 if (!drbg->meth->instantiate(drbg, entropy, entropylen,
621 nonce, noncelen, pers, perslen)) {
622 RANDerr(RAND_F_RAND_DRBG_INSTANTIATE, RAND_R_ERROR_INSTANTIATING_DRBG);
626 drbg->state = DRBG_READY;
627 drbg->reseed_gen_counter = 1;
628 drbg->reseed_time = time(NULL);
629 tsan_store(&drbg->reseed_prop_counter, drbg->reseed_next_counter);
632 if (entropy != NULL && drbg->cleanup_entropy != NULL)
633 drbg->cleanup_entropy(drbg, entropy, entropylen);
634 if (nonce != NULL && drbg->cleanup_nonce != NULL)
635 drbg->cleanup_nonce(drbg, nonce, noncelen);
636 if (drbg->state == DRBG_READY)
642 * Uninstantiate |drbg|. Must be instantiated before it can be used.
644 * Requires that drbg->lock is already locked for write, if non-null.
646 * Returns 1 on success, 0 on failure.
648 int RAND_DRBG_uninstantiate(RAND_DRBG *drbg)
650 int index = -1, type, flags;
651 if (drbg->meth == NULL) {
652 drbg->state = DRBG_ERROR;
653 RANDerr(RAND_F_RAND_DRBG_UNINSTANTIATE,
654 RAND_R_NO_DRBG_IMPLEMENTATION_SELECTED);
658 /* Clear the entire drbg->ctr struct, then reset some important
659 * members of the drbg->ctr struct (e.g. keysize, df_ks) to their
662 drbg->meth->uninstantiate(drbg);
664 /* The reset uses the default values for type and flags */
665 if (drbg->flags & RAND_DRBG_FLAG_MASTER)
666 index = RAND_DRBG_TYPE_MASTER;
667 else if (drbg->flags & RAND_DRBG_FLAG_PRIVATE)
668 index = RAND_DRBG_TYPE_PRIVATE;
669 else if (drbg->flags & RAND_DRBG_FLAG_PUBLIC)
670 index = RAND_DRBG_TYPE_PUBLIC;
673 flags = rand_drbg_flags[index];
674 type = rand_drbg_type[index];
679 return RAND_DRBG_set(drbg, type, flags);
683 * Reseed |drbg|, mixing in the specified data
685 * Requires that drbg->lock is already locked for write, if non-null.
687 * Returns 1 on success, 0 on failure.
689 int RAND_DRBG_reseed(RAND_DRBG *drbg,
690 const unsigned char *adin, size_t adinlen,
691 int prediction_resistance)
693 unsigned char *entropy = NULL;
694 size_t entropylen = 0;
696 if (drbg->state == DRBG_ERROR) {
697 RANDerr(RAND_F_RAND_DRBG_RESEED, RAND_R_IN_ERROR_STATE);
700 if (drbg->state == DRBG_UNINITIALISED) {
701 RANDerr(RAND_F_RAND_DRBG_RESEED, RAND_R_NOT_INSTANTIATED);
707 } else if (adinlen > drbg->max_adinlen) {
708 RANDerr(RAND_F_RAND_DRBG_RESEED, RAND_R_ADDITIONAL_INPUT_TOO_LONG);
712 drbg->state = DRBG_ERROR;
714 drbg->reseed_next_counter = tsan_load(&drbg->reseed_prop_counter);
715 if (drbg->reseed_next_counter) {
716 drbg->reseed_next_counter++;
717 if(!drbg->reseed_next_counter)
718 drbg->reseed_next_counter = 1;
721 if (drbg->get_entropy != NULL)
722 entropylen = drbg->get_entropy(drbg, &entropy, drbg->strength,
723 drbg->min_entropylen,
724 drbg->max_entropylen,
725 prediction_resistance);
726 if (entropylen < drbg->min_entropylen
727 || entropylen > drbg->max_entropylen) {
728 RANDerr(RAND_F_RAND_DRBG_RESEED, RAND_R_ERROR_RETRIEVING_ENTROPY);
732 if (!drbg->meth->reseed(drbg, entropy, entropylen, adin, adinlen))
735 drbg->state = DRBG_READY;
736 drbg->reseed_gen_counter = 1;
737 drbg->reseed_time = time(NULL);
738 tsan_store(&drbg->reseed_prop_counter, drbg->reseed_next_counter);
741 if (entropy != NULL && drbg->cleanup_entropy != NULL)
742 drbg->cleanup_entropy(drbg, entropy, entropylen);
743 if (drbg->state == DRBG_READY)
749 * Restart |drbg|, using the specified entropy or additional input
751 * Tries its best to get the drbg instantiated by all means,
752 * regardless of its current state.
754 * Optionally, a |buffer| of |len| random bytes can be passed,
755 * which is assumed to contain at least |entropy| bits of entropy.
757 * If |entropy| > 0, the buffer content is used as entropy input.
759 * If |entropy| == 0, the buffer content is used as additional input
761 * Returns 1 on success, 0 on failure.
763 * This function is used internally only.
765 int rand_drbg_restart(RAND_DRBG *drbg,
766 const unsigned char *buffer, size_t len, size_t entropy)
769 const unsigned char *adin = NULL;
772 if (drbg->seed_pool != NULL) {
773 RANDerr(RAND_F_RAND_DRBG_RESTART, ERR_R_INTERNAL_ERROR);
774 drbg->state = DRBG_ERROR;
775 rand_pool_free(drbg->seed_pool);
776 drbg->seed_pool = NULL;
780 if (buffer != NULL) {
782 if (drbg->max_entropylen < len) {
783 RANDerr(RAND_F_RAND_DRBG_RESTART,
784 RAND_R_ENTROPY_INPUT_TOO_LONG);
785 drbg->state = DRBG_ERROR;
789 if (entropy > 8 * len) {
790 RANDerr(RAND_F_RAND_DRBG_RESTART, RAND_R_ENTROPY_OUT_OF_RANGE);
791 drbg->state = DRBG_ERROR;
795 /* will be picked up by the rand_drbg_get_entropy() callback */
796 drbg->seed_pool = rand_pool_attach(buffer, len, entropy);
797 if (drbg->seed_pool == NULL)
800 if (drbg->max_adinlen < len) {
801 RANDerr(RAND_F_RAND_DRBG_RESTART,
802 RAND_R_ADDITIONAL_INPUT_TOO_LONG);
803 drbg->state = DRBG_ERROR;
811 /* repair error state */
812 if (drbg->state == DRBG_ERROR)
813 RAND_DRBG_uninstantiate(drbg);
815 /* repair uninitialized state */
816 if (drbg->state == DRBG_UNINITIALISED) {
817 /* reinstantiate drbg */
818 RAND_DRBG_instantiate(drbg,
819 (const unsigned char *) ossl_pers_string,
820 sizeof(ossl_pers_string) - 1);
821 /* already reseeded. prevent second reseeding below */
822 reseeded = (drbg->state == DRBG_READY);
825 /* refresh current state if entropy or additional input has been provided */
826 if (drbg->state == DRBG_READY) {
829 * mix in additional input without reseeding
831 * Similar to RAND_DRBG_reseed(), but the provided additional
832 * data |adin| is mixed into the current state without pulling
833 * entropy from the trusted entropy source using get_entropy().
834 * This is not a reseeding in the strict sense of NIST SP 800-90A.
836 drbg->meth->reseed(drbg, adin, adinlen, NULL, 0);
837 } else if (reseeded == 0) {
838 /* do a full reseeding if it has not been done yet above */
839 RAND_DRBG_reseed(drbg, NULL, 0, 0);
843 rand_pool_free(drbg->seed_pool);
844 drbg->seed_pool = NULL;
846 return drbg->state == DRBG_READY;
850 * Generate |outlen| bytes into the buffer at |out|. Reseed if we need
851 * to or if |prediction_resistance| is set. Additional input can be
852 * sent in |adin| and |adinlen|.
854 * Requires that drbg->lock is already locked for write, if non-null.
856 * Returns 1 on success, 0 on failure.
859 int RAND_DRBG_generate(RAND_DRBG *drbg, unsigned char *out, size_t outlen,
860 int prediction_resistance,
861 const unsigned char *adin, size_t adinlen)
864 int reseed_required = 0;
866 if (drbg->state != DRBG_READY) {
867 /* try to recover from previous errors */
868 rand_drbg_restart(drbg, NULL, 0, 0);
870 if (drbg->state == DRBG_ERROR) {
871 RANDerr(RAND_F_RAND_DRBG_GENERATE, RAND_R_IN_ERROR_STATE);
874 if (drbg->state == DRBG_UNINITIALISED) {
875 RANDerr(RAND_F_RAND_DRBG_GENERATE, RAND_R_NOT_INSTANTIATED);
880 if (outlen > drbg->max_request) {
881 RANDerr(RAND_F_RAND_DRBG_GENERATE, RAND_R_REQUEST_TOO_LARGE_FOR_DRBG);
884 if (adinlen > drbg->max_adinlen) {
885 RANDerr(RAND_F_RAND_DRBG_GENERATE, RAND_R_ADDITIONAL_INPUT_TOO_LONG);
889 fork_id = openssl_get_fork_id();
891 if (drbg->fork_id != fork_id) {
892 drbg->fork_id = fork_id;
896 if (drbg->reseed_interval > 0) {
897 if (drbg->reseed_gen_counter > drbg->reseed_interval)
900 if (drbg->reseed_time_interval > 0) {
901 time_t now = time(NULL);
902 if (now < drbg->reseed_time
903 || now - drbg->reseed_time >= drbg->reseed_time_interval)
906 if (drbg->parent != NULL) {
907 unsigned int reseed_counter = tsan_load(&drbg->reseed_prop_counter);
908 if (reseed_counter > 0
909 && tsan_load(&drbg->parent->reseed_prop_counter)
914 if (reseed_required || prediction_resistance) {
915 if (!RAND_DRBG_reseed(drbg, adin, adinlen, prediction_resistance)) {
916 RANDerr(RAND_F_RAND_DRBG_GENERATE, RAND_R_RESEED_ERROR);
923 if (!drbg->meth->generate(drbg, out, outlen, adin, adinlen)) {
924 drbg->state = DRBG_ERROR;
925 RANDerr(RAND_F_RAND_DRBG_GENERATE, RAND_R_GENERATE_ERROR);
929 drbg->reseed_gen_counter++;
935 * Generates |outlen| random bytes and stores them in |out|. It will
936 * using the given |drbg| to generate the bytes.
938 * Requires that drbg->lock is already locked for write, if non-null.
940 * Returns 1 on success 0 on failure.
942 int RAND_DRBG_bytes(RAND_DRBG *drbg, unsigned char *out, size_t outlen)
944 unsigned char *additional = NULL;
945 size_t additional_len;
949 if (drbg->adin_pool == NULL) {
952 drbg->adin_pool = rand_pool_new(0, 0, 0, drbg->max_adinlen);
953 if (drbg->adin_pool == NULL)
957 additional_len = rand_drbg_get_additional_data(drbg->adin_pool,
960 for ( ; outlen > 0; outlen -= chunk, out += chunk) {
962 if (chunk > drbg->max_request)
963 chunk = drbg->max_request;
964 ret = RAND_DRBG_generate(drbg, out, chunk, 0, additional, additional_len);
971 if (additional != NULL)
972 rand_drbg_cleanup_additional_data(drbg->adin_pool, additional);
978 * Set the RAND_DRBG callbacks for obtaining entropy and nonce.
980 * Setting the callbacks is allowed only if the drbg has not been
981 * initialized yet. Otherwise, the operation will fail.
983 * Returns 1 on success, 0 on failure.
985 int RAND_DRBG_set_callbacks(RAND_DRBG *drbg,
986 RAND_DRBG_get_entropy_fn get_entropy,
987 RAND_DRBG_cleanup_entropy_fn cleanup_entropy,
988 RAND_DRBG_get_nonce_fn get_nonce,
989 RAND_DRBG_cleanup_nonce_fn cleanup_nonce)
991 if (drbg->state != DRBG_UNINITIALISED
992 || drbg->parent != NULL)
994 drbg->get_entropy = get_entropy;
995 drbg->cleanup_entropy = cleanup_entropy;
996 drbg->get_nonce = get_nonce;
997 drbg->cleanup_nonce = cleanup_nonce;
1002 * Set the reseed interval.
1004 * The drbg will reseed automatically whenever the number of generate
1005 * requests exceeds the given reseed interval. If the reseed interval
1006 * is 0, then this feature is disabled.
1008 * Returns 1 on success, 0 on failure.
1010 int RAND_DRBG_set_reseed_interval(RAND_DRBG *drbg, unsigned int interval)
1012 if (interval > MAX_RESEED_INTERVAL)
1014 drbg->reseed_interval = interval;
1019 * Set the reseed time interval.
1021 * The drbg will reseed automatically whenever the time elapsed since
1022 * the last reseeding exceeds the given reseed time interval. For safety,
1023 * a reseeding will also occur if the clock has been reset to a smaller
1026 * Returns 1 on success, 0 on failure.
1028 int RAND_DRBG_set_reseed_time_interval(RAND_DRBG *drbg, time_t interval)
1030 if (interval > MAX_RESEED_TIME_INTERVAL)
1032 drbg->reseed_time_interval = interval;
1037 * Set the default values for reseed (time) intervals of new DRBG instances
1039 * The default values can be set independently for master DRBG instances
1040 * (without a parent) and slave DRBG instances (with parent).
1042 * Returns 1 on success, 0 on failure.
1045 int RAND_DRBG_set_reseed_defaults(
1046 unsigned int _master_reseed_interval,
1047 unsigned int _slave_reseed_interval,
1048 time_t _master_reseed_time_interval,
1049 time_t _slave_reseed_time_interval
1052 if (_master_reseed_interval > MAX_RESEED_INTERVAL
1053 || _slave_reseed_interval > MAX_RESEED_INTERVAL)
1056 if (_master_reseed_time_interval > MAX_RESEED_TIME_INTERVAL
1057 || _slave_reseed_time_interval > MAX_RESEED_TIME_INTERVAL)
1060 master_reseed_interval = _master_reseed_interval;
1061 slave_reseed_interval = _slave_reseed_interval;
1063 master_reseed_time_interval = _master_reseed_time_interval;
1064 slave_reseed_time_interval = _slave_reseed_time_interval;
1070 * Locks the given drbg. Locking a drbg which does not have locking
1071 * enabled is considered a successful no-op.
1073 * Returns 1 on success, 0 on failure.
1075 int rand_drbg_lock(RAND_DRBG *drbg)
1077 if (drbg->lock != NULL)
1078 return CRYPTO_THREAD_write_lock(drbg->lock);
1084 * Unlocks the given drbg. Unlocking a drbg which does not have locking
1085 * enabled is considered a successful no-op.
1087 * Returns 1 on success, 0 on failure.
1089 int rand_drbg_unlock(RAND_DRBG *drbg)
1091 if (drbg->lock != NULL)
1092 return CRYPTO_THREAD_unlock(drbg->lock);
1098 * Enables locking for the given drbg
1100 * Locking can only be enabled if the random generator
1101 * is in the uninitialized state.
1103 * Returns 1 on success, 0 on failure.
1105 int rand_drbg_enable_locking(RAND_DRBG *drbg)
1107 if (drbg->state != DRBG_UNINITIALISED) {
1108 RANDerr(RAND_F_RAND_DRBG_ENABLE_LOCKING,
1109 RAND_R_DRBG_ALREADY_INITIALIZED);
1113 if (drbg->lock == NULL) {
1114 if (drbg->parent != NULL && drbg->parent->lock == NULL) {
1115 RANDerr(RAND_F_RAND_DRBG_ENABLE_LOCKING,
1116 RAND_R_PARENT_LOCKING_NOT_ENABLED);
1120 drbg->lock = CRYPTO_THREAD_lock_new();
1121 if (drbg->lock == NULL) {
1122 RANDerr(RAND_F_RAND_DRBG_ENABLE_LOCKING,
1123 RAND_R_FAILED_TO_CREATE_LOCK);
1133 * Get and set the EXDATA
1135 int RAND_DRBG_set_ex_data(RAND_DRBG *drbg, int idx, void *arg)
1137 return CRYPTO_set_ex_data(&drbg->ex_data, idx, arg);
1140 void *RAND_DRBG_get_ex_data(const RAND_DRBG *drbg, int idx)
1142 return CRYPTO_get_ex_data(&drbg->ex_data, idx);
1147 * The following functions provide a RAND_METHOD that works on the
1148 * global DRBG. They lock.
1152 * Allocates a new global DRBG on the secure heap (if enabled) and
1153 * initializes it with default settings.
1155 * Returns a pointer to the new DRBG instance on success, NULL on failure.
1157 static RAND_DRBG *drbg_setup(OPENSSL_CTX *ctx, RAND_DRBG *parent, int drbg_type)
1161 drbg = RAND_DRBG_secure_new_ex(ctx, rand_drbg_type[drbg_type],
1162 rand_drbg_flags[drbg_type], parent);
1166 /* Only the master DRBG needs to have a lock */
1167 if (parent == NULL && rand_drbg_enable_locking(drbg) == 0)
1170 /* enable seed propagation */
1171 tsan_store(&drbg->reseed_prop_counter, 1);
1174 * Ignore instantiation error to support just-in-time instantiation.
1176 * The state of the drbg will be checked in RAND_DRBG_generate() and
1177 * an automatic recovery is attempted.
1179 (void)RAND_DRBG_instantiate(drbg,
1180 (const unsigned char *) ossl_pers_string,
1181 sizeof(ossl_pers_string) - 1);
1185 RAND_DRBG_free(drbg);
1189 static void drbg_delete_thread_state(void *arg)
1191 OPENSSL_CTX *ctx = arg;
1192 DRBG_GLOBAL *dgbl = drbg_get_global(ctx);
1197 drbg = CRYPTO_THREAD_get_local(&dgbl->public_drbg);
1198 CRYPTO_THREAD_set_local(&dgbl->public_drbg, NULL);
1199 RAND_DRBG_free(drbg);
1201 drbg = CRYPTO_THREAD_get_local(&dgbl->private_drbg);
1202 CRYPTO_THREAD_set_local(&dgbl->private_drbg, NULL);
1203 RAND_DRBG_free(drbg);
1206 /* Implements the default OpenSSL RAND_bytes() method */
1207 static int drbg_bytes(unsigned char *out, int count)
1210 RAND_DRBG *drbg = RAND_DRBG_get0_public();
1215 ret = RAND_DRBG_bytes(drbg, out, count);
1221 * Calculates the minimum length of a full entropy buffer
1222 * which is necessary to seed (i.e. instantiate) the DRBG
1225 size_t rand_drbg_seedlen(RAND_DRBG *drbg)
1228 * If no os entropy source is available then RAND_seed(buffer, bufsize)
1229 * is expected to succeed if and only if the buffer length satisfies
1230 * the following requirements, which follow from the calculations
1231 * in RAND_DRBG_instantiate().
1233 size_t min_entropy = drbg->strength;
1234 size_t min_entropylen = drbg->min_entropylen;
1237 * Extra entropy for the random nonce in the absence of a
1238 * get_nonce callback, see comment in RAND_DRBG_instantiate().
1240 if (drbg->min_noncelen > 0 && drbg->get_nonce == NULL) {
1241 min_entropy += drbg->strength / 2;
1242 min_entropylen += drbg->min_noncelen;
1246 * Convert entropy requirement from bits to bytes
1247 * (dividing by 8 without rounding upwards, because
1248 * all entropy requirements are divisible by 8).
1252 /* Return a value that satisfies both requirements */
1253 return min_entropy > min_entropylen ? min_entropy : min_entropylen;
1256 /* Implements the default OpenSSL RAND_add() method */
1257 static int drbg_add(const void *buf, int num, double randomness)
1260 RAND_DRBG *drbg = RAND_DRBG_get0_master();
1267 if (num < 0 || randomness < 0.0)
1270 rand_drbg_lock(drbg);
1271 seedlen = rand_drbg_seedlen(drbg);
1273 buflen = (size_t)num;
1277 * NIST SP-800-90A mandates that entropy *shall not* be provided
1278 * by the consuming application. By setting the randomness to zero,
1279 * we ensure that the buffer contents will be added to the internal
1280 * state of the DRBG only as additional data.
1282 * (NIST SP-800-90Ar1, Sections 9.1 and 9.2)
1286 if (buflen < seedlen || randomness < (double) seedlen) {
1287 #if defined(OPENSSL_RAND_SEED_NONE)
1289 * If no os entropy source is available, a reseeding will fail
1290 * inevitably. So we use a trick to mix the buffer contents into
1291 * the DRBG state without forcing a reseeding: we generate a
1292 * dummy random byte, using the buffer content as additional data.
1293 * Note: This won't work with RAND_DRBG_FLAG_CTR_NO_DF.
1295 unsigned char dummy[1];
1297 ret = RAND_DRBG_generate(drbg, dummy, sizeof(dummy), 0, buf, buflen);
1298 rand_drbg_unlock(drbg);
1302 * If an os entropy source is available then we declare the buffer content
1303 * as additional data by setting randomness to zero and trigger a regular
1310 if (randomness > (double)seedlen) {
1312 * The purpose of this check is to bound |randomness| by a
1313 * relatively small value in order to prevent an integer
1314 * overflow when multiplying by 8 in the rand_drbg_restart()
1315 * call below. Note that randomness is measured in bytes,
1316 * not bits, so this value corresponds to eight times the
1317 * security strength.
1319 randomness = (double)seedlen;
1322 ret = rand_drbg_restart(drbg, buf, buflen, (size_t)(8 * randomness));
1323 rand_drbg_unlock(drbg);
1328 /* Implements the default OpenSSL RAND_seed() method */
1329 static int drbg_seed(const void *buf, int num)
1331 return drbg_add(buf, num, num);
1334 /* Implements the default OpenSSL RAND_status() method */
1335 static int drbg_status(void)
1338 RAND_DRBG *drbg = RAND_DRBG_get0_master();
1343 rand_drbg_lock(drbg);
1344 ret = drbg->state == DRBG_READY ? 1 : 0;
1345 rand_drbg_unlock(drbg);
1350 * Get the master DRBG.
1351 * Returns pointer to the DRBG on success, NULL on failure.
1354 RAND_DRBG *OPENSSL_CTX_get0_master_drbg(OPENSSL_CTX *ctx)
1356 DRBG_GLOBAL *dgbl = drbg_get_global(ctx);
1361 return dgbl->master_drbg;
1364 RAND_DRBG *RAND_DRBG_get0_master(void)
1366 return OPENSSL_CTX_get0_master_drbg(NULL);
1370 * Get the public DRBG.
1371 * Returns pointer to the DRBG on success, NULL on failure.
1373 RAND_DRBG *OPENSSL_CTX_get0_public_drbg(OPENSSL_CTX *ctx)
1375 DRBG_GLOBAL *dgbl = drbg_get_global(ctx);
1381 drbg = CRYPTO_THREAD_get_local(&dgbl->public_drbg);
1383 ctx = openssl_ctx_get_concrete(ctx);
1385 * If the private_drbg is also NULL then this is the first time we've
1388 if (CRYPTO_THREAD_get_local(&dgbl->private_drbg) == NULL
1389 && !ossl_init_thread_start(NULL, ctx, drbg_delete_thread_state))
1391 drbg = drbg_setup(ctx, dgbl->master_drbg, RAND_DRBG_TYPE_PUBLIC);
1392 CRYPTO_THREAD_set_local(&dgbl->public_drbg, drbg);
1397 RAND_DRBG *RAND_DRBG_get0_public(void)
1399 return OPENSSL_CTX_get0_public_drbg(NULL);
1403 * Get the private DRBG.
1404 * Returns pointer to the DRBG on success, NULL on failure.
1406 RAND_DRBG *OPENSSL_CTX_get0_private_drbg(OPENSSL_CTX *ctx)
1408 DRBG_GLOBAL *dgbl = drbg_get_global(ctx);
1414 drbg = CRYPTO_THREAD_get_local(&dgbl->private_drbg);
1416 ctx = openssl_ctx_get_concrete(ctx);
1418 * If the public_drbg is also NULL then this is the first time we've
1421 if (CRYPTO_THREAD_get_local(&dgbl->public_drbg) == NULL
1422 && !ossl_init_thread_start(NULL, ctx, drbg_delete_thread_state))
1424 drbg = drbg_setup(ctx, dgbl->master_drbg, RAND_DRBG_TYPE_PRIVATE);
1425 CRYPTO_THREAD_set_local(&dgbl->private_drbg, drbg);
1430 RAND_DRBG *RAND_DRBG_get0_private(void)
1432 return OPENSSL_CTX_get0_private_drbg(NULL);
1435 RAND_METHOD rand_meth = {
1444 RAND_METHOD *RAND_OpenSSL(void)