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"
19 * Support framework for NIST SP 800-90A DRBG, AES-CTR mode.
20 * The RAND_DRBG is OpenSSL's pointer to an instance of the DRBG.
22 * The OpenSSL model is to have new and free functions, and that new
23 * does all initialization. That is not the NIST model, which has
24 * instantiation and un-instantiate, and re-use within a new/free
25 * lifecycle. (No doubt this comes from the desire to support hardware
26 * DRBG, where allocation of resources on something like an HSM is
27 * a much bigger deal than just re-setting an allocated resource.)
31 * THE THREE SHARED DRBGs
33 * There are three shared DRBGs (master, public and private), which are
34 * accessed concurrently by all threads.
38 * Not used directly by the application, only for reseeding the two other
39 * DRBGs. It reseeds itself by pulling either randomness from os entropy
40 * sources or by consuming randomnes which was added by RAND_add()
42 static RAND_DRBG *drbg_master;
46 * Used by default for generating random bytes using RAND_bytes().
48 static RAND_DRBG *drbg_public;
52 * Used by default for generating private keys using RAND_priv_bytes()
54 static RAND_DRBG *drbg_private;
58 * In addition there are DRBGs, which are not shared, but used only by a
59 * single thread at every time, for example the DRBGs which are owned by
60 * an SSL context. All DRBGs are organized in a hierarchical fashion
61 * with the <master> DRBG as root.
63 * This gives the following overall picture:
65 * <os entropy sources>
67 * RAND_add() ==> <master> \
68 * / \ | shared DRBGs (with locking)
69 * <public> <private> /
71 * <ssl> owned by an SSL context
75 * Before satisfying a generate request, a DRBG reseeds itself automatically,
76 * if one of the following two conditions holds:
78 * - the number of generate requests since the last reseeding exceeds a
79 * certain threshold, the so called |reseed_interval|. This behaviour
80 * can be disabled by setting the |reseed_interval| to 0.
82 * - the time elapsed since the last reseeding exceeds a certain time
83 * interval, the so called |reseed_time_interval|. This behaviour
84 * can be disabled by setting the |reseed_time_interval| to 0.
88 * For the three shared DRBGs (and only for these) there is another way to
89 * reseed them manually by calling RAND_seed() (or RAND_add() with a positive
90 * |randomness| argument). This will immediately reseed the <master> DRBG.
91 * The <public> and <private> DRBG will detect this on their next generate
92 * call and reseed, pulling randomness from <master>.
96 * The three shared DRBGs are intended to be used concurrently, so they
97 * support locking. The RAND methods take the locks automatically, so using
98 * the RAND api (in particular RAND_bytes() and RAND_priv_bytes()) is
99 * thread-safe. Note however that accessing the shared DRBGs directly via
100 * the RAND_DRBG interface is *not* thread-safe.
102 * All other DRBG instances don't support locking, because they are
103 * intendended to be used by a single thread. Instead of accessing a single
104 * DRBG instance concurrently from different threads, it is recommended to
105 * instantiate a separate DRBG instance per thread. Using the same shared
106 * DRBG (preferrably the public DRBG) as parent of DRBG instances on
107 * different threads is safe.
111 /* NIST SP 800-90A DRBG recommends the use of a personalization string. */
112 static const char ossl_pers_string[] = "OpenSSL NIST SP 800-90A DRBG";
114 static CRYPTO_ONCE rand_drbg_init = CRYPTO_ONCE_STATIC_INIT;
116 static unsigned int master_reseed_interval = MASTER_RESEED_INTERVAL;
117 static unsigned int slave_reseed_interval = SLAVE_RESEED_INTERVAL;
119 static time_t master_reseed_time_interval = MASTER_RESEED_TIME_INTERVAL;
120 static time_t slave_reseed_time_interval = SLAVE_RESEED_TIME_INTERVAL;
122 static RAND_DRBG *drbg_setup(RAND_DRBG *parent);
124 static RAND_DRBG *rand_drbg_new(int secure,
130 * Set/initialize |drbg| to be of type |nid|, with optional |flags|.
132 * Returns 1 on success, 0 on failure.
134 int RAND_DRBG_set(RAND_DRBG *drbg, int nid, unsigned int flags)
138 drbg->state = DRBG_UNINITIALISED;
144 RANDerr(RAND_F_RAND_DRBG_SET, RAND_R_UNSUPPORTED_DRBG_TYPE);
147 /* Uninitialized; that's okay. */
149 case NID_aes_128_ctr:
150 case NID_aes_192_ctr:
151 case NID_aes_256_ctr:
152 ret = drbg_ctr_init(drbg);
157 RANDerr(RAND_F_RAND_DRBG_SET, RAND_R_ERROR_INITIALISING_DRBG);
162 * Allocate memory and initialize a new DRBG. The DRBG is allocated on
163 * the secure heap if |secure| is nonzero and the secure heap is enabled.
164 * The |parent|, if not NULL, will be used as random source for reseeding.
166 * Returns a pointer to the new DRBG instance on success, NULL on failure.
168 static RAND_DRBG *rand_drbg_new(int secure,
173 RAND_DRBG *drbg = secure ?
174 OPENSSL_secure_zalloc(sizeof(*drbg)) : OPENSSL_zalloc(sizeof(*drbg));
177 RANDerr(RAND_F_RAND_DRBG_NEW, ERR_R_MALLOC_FAILURE);
181 drbg->secure = secure && CRYPTO_secure_allocated(drbg);
182 drbg->fork_count = rand_fork_count;
183 drbg->parent = parent;
185 if (parent == NULL) {
186 drbg->reseed_interval = master_reseed_interval;
187 drbg->reseed_time_interval = master_reseed_time_interval;
189 drbg->reseed_interval = slave_reseed_interval;
190 drbg->reseed_time_interval = slave_reseed_time_interval;
193 if (RAND_DRBG_set(drbg, type, flags) == 0)
196 if (parent != NULL && drbg->strength > parent->strength) {
198 * We currently don't support the algorithm from NIST SP 800-90C
199 * 10.1.2 to use a weaker DRBG as source
201 RANDerr(RAND_F_RAND_DRBG_NEW, RAND_R_PARENT_STRENGTH_TOO_WEAK);
205 if (!RAND_DRBG_set_callbacks(drbg, rand_drbg_get_entropy,
206 rand_drbg_cleanup_entropy,
214 OPENSSL_secure_free(drbg);
221 RAND_DRBG *RAND_DRBG_new(int type, unsigned int flags, RAND_DRBG *parent)
223 return rand_drbg_new(0, type, flags, parent);
226 RAND_DRBG *RAND_DRBG_secure_new(int type, unsigned int flags, RAND_DRBG *parent)
228 return rand_drbg_new(1, type, flags, parent);
232 * Uninstantiate |drbg| and free all memory.
234 void RAND_DRBG_free(RAND_DRBG *drbg)
239 if (drbg->meth != NULL)
240 drbg->meth->uninstantiate(drbg);
241 CRYPTO_THREAD_lock_free(drbg->lock);
242 CRYPTO_free_ex_data(CRYPTO_EX_INDEX_DRBG, drbg, &drbg->ex_data);
245 OPENSSL_secure_clear_free(drbg, sizeof(*drbg));
247 OPENSSL_clear_free(drbg, sizeof(*drbg));
251 * Instantiate |drbg|, after it has been initialized. Use |pers| and
252 * |perslen| as prediction-resistance input.
254 * Requires that drbg->lock is already locked for write, if non-null.
256 * Returns 1 on success, 0 on failure.
258 int RAND_DRBG_instantiate(RAND_DRBG *drbg,
259 const unsigned char *pers, size_t perslen)
261 unsigned char *nonce = NULL, *entropy = NULL;
262 size_t noncelen = 0, entropylen = 0;
264 if (perslen > drbg->max_perslen) {
265 RANDerr(RAND_F_RAND_DRBG_INSTANTIATE,
266 RAND_R_PERSONALISATION_STRING_TOO_LONG);
270 if (drbg->meth == NULL)
272 RANDerr(RAND_F_RAND_DRBG_INSTANTIATE,
273 RAND_R_NO_DRBG_IMPLEMENTATION_SELECTED);
277 if (drbg->state != DRBG_UNINITIALISED) {
278 RANDerr(RAND_F_RAND_DRBG_INSTANTIATE,
279 drbg->state == DRBG_ERROR ? RAND_R_IN_ERROR_STATE
280 : RAND_R_ALREADY_INSTANTIATED);
284 drbg->state = DRBG_ERROR;
285 if (drbg->get_entropy != NULL)
286 entropylen = drbg->get_entropy(drbg, &entropy, drbg->strength,
287 drbg->min_entropylen, drbg->max_entropylen);
288 if (entropylen < drbg->min_entropylen
289 || entropylen > drbg->max_entropylen) {
290 RANDerr(RAND_F_RAND_DRBG_INSTANTIATE, RAND_R_ERROR_RETRIEVING_ENTROPY);
294 if (drbg->max_noncelen > 0 && drbg->get_nonce != NULL) {
295 noncelen = drbg->get_nonce(drbg, &nonce, drbg->strength / 2,
296 drbg->min_noncelen, drbg->max_noncelen);
297 if (noncelen < drbg->min_noncelen || noncelen > drbg->max_noncelen) {
298 RANDerr(RAND_F_RAND_DRBG_INSTANTIATE,
299 RAND_R_ERROR_RETRIEVING_NONCE);
304 if (!drbg->meth->instantiate(drbg, entropy, entropylen,
305 nonce, noncelen, pers, perslen)) {
306 RANDerr(RAND_F_RAND_DRBG_INSTANTIATE, RAND_R_ERROR_INSTANTIATING_DRBG);
310 drbg->state = DRBG_READY;
311 drbg->generate_counter = 0;
312 drbg->reseed_time = time(NULL);
313 if (drbg->reseed_counter > 0) {
314 if (drbg->parent == NULL)
315 drbg->reseed_counter++;
317 drbg->reseed_counter = drbg->parent->reseed_counter;
321 if (entropy != NULL && drbg->cleanup_entropy != NULL)
322 drbg->cleanup_entropy(drbg, entropy, entropylen);
323 if (nonce != NULL && drbg->cleanup_nonce!= NULL )
324 drbg->cleanup_nonce(drbg, nonce, noncelen);
325 if (drbg->pool != NULL) {
326 if (drbg->state == DRBG_READY) {
327 RANDerr(RAND_F_RAND_DRBG_INSTANTIATE,
328 RAND_R_ERROR_ENTROPY_POOL_WAS_IGNORED);
329 drbg->state = DRBG_ERROR;
331 RAND_POOL_free(drbg->pool);
334 if (drbg->state == DRBG_READY)
340 * Uninstantiate |drbg|. Must be instantiated before it can be used.
342 * Requires that drbg->lock is already locked for write, if non-null.
344 * Returns 1 on success, 0 on failure.
346 int RAND_DRBG_uninstantiate(RAND_DRBG *drbg)
348 if (drbg->meth == NULL)
350 RANDerr(RAND_F_RAND_DRBG_UNINSTANTIATE,
351 RAND_R_NO_DRBG_IMPLEMENTATION_SELECTED);
355 /* Clear the entire drbg->ctr struct, then reset some important
356 * members of the drbg->ctr struct (e.g. keysize, df_ks) to their
359 drbg->meth->uninstantiate(drbg);
360 return RAND_DRBG_set(drbg, drbg->nid, drbg->flags);
364 * Reseed |drbg|, mixing in the specified data
366 * Requires that drbg->lock is already locked for write, if non-null.
368 * Returns 1 on success, 0 on failure.
370 int RAND_DRBG_reseed(RAND_DRBG *drbg,
371 const unsigned char *adin, size_t adinlen)
373 unsigned char *entropy = NULL;
374 size_t entropylen = 0;
376 if (drbg->state == DRBG_ERROR) {
377 RANDerr(RAND_F_RAND_DRBG_RESEED, RAND_R_IN_ERROR_STATE);
380 if (drbg->state == DRBG_UNINITIALISED) {
381 RANDerr(RAND_F_RAND_DRBG_RESEED, RAND_R_NOT_INSTANTIATED);
387 else if (adinlen > drbg->max_adinlen) {
388 RANDerr(RAND_F_RAND_DRBG_RESEED, RAND_R_ADDITIONAL_INPUT_TOO_LONG);
392 drbg->state = DRBG_ERROR;
393 if (drbg->get_entropy != NULL)
394 entropylen = drbg->get_entropy(drbg, &entropy, drbg->strength,
395 drbg->min_entropylen, drbg->max_entropylen);
396 if (entropylen < drbg->min_entropylen
397 || entropylen > drbg->max_entropylen) {
398 RANDerr(RAND_F_RAND_DRBG_RESEED, RAND_R_ERROR_RETRIEVING_ENTROPY);
402 if (!drbg->meth->reseed(drbg, entropy, entropylen, adin, adinlen))
405 drbg->state = DRBG_READY;
406 drbg->generate_counter = 0;
407 drbg->reseed_time = time(NULL);
408 if (drbg->reseed_counter > 0) {
409 if (drbg->parent == NULL)
410 drbg->reseed_counter++;
412 drbg->reseed_counter = drbg->parent->reseed_counter;
416 if (entropy != NULL && drbg->cleanup_entropy != NULL)
417 drbg->cleanup_entropy(drbg, entropy, entropylen);
418 if (drbg->state == DRBG_READY)
424 * Restart |drbg|, using the specified entropy or additional input
426 * Tries its best to get the drbg instantiated by all means,
427 * regardless of its current state.
429 * Optionally, a |buffer| of |len| random bytes can be passed,
430 * which is assumed to contain at least |entropy| bits of entropy.
432 * If |entropy| > 0, the buffer content is used as entropy input.
434 * If |entropy| == 0, the buffer content is used as additional input
436 * Returns 1 on success, 0 on failure.
438 * This function is used internally only.
440 int rand_drbg_restart(RAND_DRBG *drbg,
441 const unsigned char *buffer, size_t len, size_t entropy)
444 const unsigned char *adin = NULL;
447 if (drbg->pool != NULL) {
448 RANDerr(RAND_F_RAND_DRBG_RESTART, ERR_R_INTERNAL_ERROR);
449 RAND_POOL_free(drbg->pool);
453 if (buffer != NULL) {
455 if (drbg->max_entropylen < len) {
456 RANDerr(RAND_F_RAND_DRBG_RESTART,
457 RAND_R_ENTROPY_INPUT_TOO_LONG);
461 if (entropy > 8 * len) {
462 RANDerr(RAND_F_RAND_DRBG_RESTART, RAND_R_ENTROPY_OUT_OF_RANGE);
466 /* will be picked up by the rand_drbg_get_entropy() callback */
467 drbg->pool = RAND_POOL_new(entropy, len, len);
468 if (drbg->pool == NULL)
471 RAND_POOL_add(drbg->pool, buffer, len, entropy);
473 if (drbg->max_adinlen < len) {
474 RANDerr(RAND_F_RAND_DRBG_RESTART,
475 RAND_R_ADDITIONAL_INPUT_TOO_LONG);
483 /* repair error state */
484 if (drbg->state == DRBG_ERROR)
485 RAND_DRBG_uninstantiate(drbg);
487 /* repair uninitialized state */
488 if (drbg->state == DRBG_UNINITIALISED) {
489 /* reinstantiate drbg */
490 RAND_DRBG_instantiate(drbg,
491 (const unsigned char *) ossl_pers_string,
492 sizeof(ossl_pers_string) - 1);
493 /* already reseeded. prevent second reseeding below */
494 reseeded = (drbg->state == DRBG_READY);
497 /* refresh current state if entropy or additional input has been provided */
498 if (drbg->state == DRBG_READY) {
501 * mix in additional input without reseeding
503 * Similar to RAND_DRBG_reseed(), but the provided additional
504 * data |adin| is mixed into the current state without pulling
505 * entropy from the trusted entropy source using get_entropy().
506 * This is not a reseeding in the strict sense of NIST SP 800-90A.
508 drbg->meth->reseed(drbg, adin, adinlen, NULL, 0);
509 } else if (reseeded == 0) {
510 /* do a full reseeding if it has not been done yet above */
511 RAND_DRBG_reseed(drbg, NULL, 0);
515 /* check whether a given entropy pool was cleared properly during reseed */
516 if (drbg->pool != NULL) {
517 drbg->state = DRBG_ERROR;
518 RANDerr(RAND_F_RAND_DRBG_RESTART, ERR_R_INTERNAL_ERROR);
519 RAND_POOL_free(drbg->pool);
524 return drbg->state == DRBG_READY;
528 * Generate |outlen| bytes into the buffer at |out|. Reseed if we need
529 * to or if |prediction_resistance| is set. Additional input can be
530 * sent in |adin| and |adinlen|.
532 * Requires that drbg->lock is already locked for write, if non-null.
534 * Returns 1 on success, 0 on failure.
537 int RAND_DRBG_generate(RAND_DRBG *drbg, unsigned char *out, size_t outlen,
538 int prediction_resistance,
539 const unsigned char *adin, size_t adinlen)
541 int reseed_required = 0;
543 if (drbg->state != DRBG_READY) {
544 /* try to recover from previous errors */
545 rand_drbg_restart(drbg, NULL, 0, 0);
547 if (drbg->state == DRBG_ERROR) {
548 RANDerr(RAND_F_RAND_DRBG_GENERATE, RAND_R_IN_ERROR_STATE);
551 if (drbg->state == DRBG_UNINITIALISED) {
552 RANDerr(RAND_F_RAND_DRBG_GENERATE, RAND_R_NOT_INSTANTIATED);
557 if (outlen > drbg->max_request) {
558 RANDerr(RAND_F_RAND_DRBG_GENERATE, RAND_R_REQUEST_TOO_LARGE_FOR_DRBG);
561 if (adinlen > drbg->max_adinlen) {
562 RANDerr(RAND_F_RAND_DRBG_GENERATE, RAND_R_ADDITIONAL_INPUT_TOO_LONG);
566 if (drbg->fork_count != rand_fork_count) {
567 drbg->fork_count = rand_fork_count;
571 if (drbg->reseed_interval > 0) {
572 if (drbg->generate_counter >= drbg->reseed_interval)
575 if (drbg->reseed_time_interval > 0) {
576 time_t now = time(NULL);
577 if (now < drbg->reseed_time
578 || now - drbg->reseed_time >= drbg->reseed_time_interval)
581 if (drbg->reseed_counter > 0 && drbg->parent != NULL) {
582 if (drbg->reseed_counter != drbg->parent->reseed_counter)
586 if (reseed_required || prediction_resistance) {
587 if (!RAND_DRBG_reseed(drbg, adin, adinlen)) {
588 RANDerr(RAND_F_RAND_DRBG_GENERATE, RAND_R_RESEED_ERROR);
595 if (!drbg->meth->generate(drbg, out, outlen, adin, adinlen)) {
596 drbg->state = DRBG_ERROR;
597 RANDerr(RAND_F_RAND_DRBG_GENERATE, RAND_R_GENERATE_ERROR);
601 drbg->generate_counter++;
607 * Generates |outlen| random bytes and stores them in |out|. It will
608 * using the given |drbg| to generate the bytes.
610 * Requires that drbg->lock is already locked for write, if non-null.
612 * Returns 1 on success 0 on failure.
614 int RAND_DRBG_bytes(RAND_DRBG *drbg, unsigned char *out, size_t outlen)
616 unsigned char *additional = NULL;
617 size_t additional_len;
621 additional_len = rand_drbg_get_additional_data(&additional, drbg->max_adinlen);
623 for ( ; outlen > 0; outlen -= chunk, out += chunk) {
625 if (chunk > drbg->max_request)
626 chunk = drbg->max_request;
627 ret = RAND_DRBG_generate(drbg, out, chunk, 0, additional, additional_len);
634 if (additional_len != 0)
635 OPENSSL_secure_clear_free(additional, additional_len);
641 * Set the RAND_DRBG callbacks for obtaining entropy and nonce.
643 * In the following, the signature and the semantics of the
644 * get_entropy() and cleanup_entropy() callbacks are explained.
648 * size_t get_entropy(RAND_DRBG *ctx,
649 * unsigned char **pout,
651 * size_t min_len, size_t max_len);
653 * This is a request to allocate and fill a buffer of size
654 * |min_len| <= size <= |max_len| (in bytes) which contains
655 * at least |entropy| bits of randomness. The buffer's address is
656 * to be returned in |*pout| and the number of collected
657 * randomness bytes (which may be less than the allocated size
658 * of the buffer) as return value.
660 * If the callback fails to acquire at least |entropy| bits of
661 * randomness, it shall return a buffer length of 0.
665 * void cleanup_entropy(RAND_DRBG *ctx,
666 * unsigned char *out, size_t outlen);
668 * A request to clear and free the buffer allocated by get_entropy().
669 * The values |out| and |outlen| are expected to be the random buffer's
670 * address and length, as returned by the get_entropy() callback.
672 * GET_NONCE, CLEANUP_NONCE
674 * Signature and semantics of the get_nonce() and cleanup_nonce()
675 * callbacks are analogous to get_entropy() and cleanup_entropy().
676 * Currently, the nonce is used only for the known answer tests.
678 int RAND_DRBG_set_callbacks(RAND_DRBG *drbg,
679 RAND_DRBG_get_entropy_fn get_entropy,
680 RAND_DRBG_cleanup_entropy_fn cleanup_entropy,
681 RAND_DRBG_get_nonce_fn get_nonce,
682 RAND_DRBG_cleanup_nonce_fn cleanup_nonce)
684 if (drbg->state != DRBG_UNINITIALISED)
686 drbg->get_entropy = get_entropy;
687 drbg->cleanup_entropy = cleanup_entropy;
688 drbg->get_nonce = get_nonce;
689 drbg->cleanup_nonce = cleanup_nonce;
694 * Set the reseed interval.
696 * The drbg will reseed automatically whenever the number of generate
697 * requests exceeds the given reseed interval. If the reseed interval
698 * is 0, then this feature is disabled.
700 * Returns 1 on success, 0 on failure.
702 int RAND_DRBG_set_reseed_interval(RAND_DRBG *drbg, unsigned int interval)
704 if (interval > MAX_RESEED_INTERVAL)
706 drbg->reseed_interval = interval;
711 * Set the reseed time interval.
713 * The drbg will reseed automatically whenever the time elapsed since
714 * the last reseeding exceeds the given reseed time interval. For safety,
715 * a reseeding will also occur if the clock has been reset to a smaller
718 * Returns 1 on success, 0 on failure.
720 int RAND_DRBG_set_reseed_time_interval(RAND_DRBG *drbg, time_t interval)
722 if (interval > MAX_RESEED_TIME_INTERVAL)
724 drbg->reseed_time_interval = interval;
729 * Set the default values for reseed (time) intervals of new DRBG instances
731 * The default values can be set independently for master DRBG instances
732 * (without a parent) and slave DRBG instances (with parent).
734 * Returns 1 on success, 0 on failure.
737 int RAND_DRBG_set_reseed_defaults(
738 unsigned int _master_reseed_interval,
739 unsigned int _slave_reseed_interval,
740 time_t _master_reseed_time_interval,
741 time_t _slave_reseed_time_interval
744 if (_master_reseed_interval > MAX_RESEED_INTERVAL
745 || _slave_reseed_interval > MAX_RESEED_INTERVAL)
748 if (_master_reseed_time_interval > MAX_RESEED_TIME_INTERVAL
749 || _slave_reseed_time_interval > MAX_RESEED_TIME_INTERVAL)
752 master_reseed_interval = _master_reseed_interval;
753 slave_reseed_interval = _slave_reseed_interval;
755 master_reseed_time_interval = _master_reseed_time_interval;
756 slave_reseed_time_interval = _slave_reseed_time_interval;
762 * Locks the given drbg. Locking a drbg which does not have locking
763 * enabled is considered a successful no-op.
765 * Returns 1 on success, 0 on failure.
767 int rand_drbg_lock(RAND_DRBG *drbg)
769 if (drbg->lock != NULL)
770 return CRYPTO_THREAD_write_lock(drbg->lock);
776 * Unlocks the given drbg. Unlocking a drbg which does not have locking
777 * enabled is considered a successful no-op.
779 * Returns 1 on success, 0 on failure.
781 int rand_drbg_unlock(RAND_DRBG *drbg)
783 if (drbg->lock != NULL)
784 return CRYPTO_THREAD_unlock(drbg->lock);
790 * Enables locking for the given drbg
792 * Locking can only be enabled if the random generator
793 * is in the uninitialized state.
795 * Returns 1 on success, 0 on failure.
797 int rand_drbg_enable_locking(RAND_DRBG *drbg)
799 if (drbg->state != DRBG_UNINITIALISED) {
800 RANDerr(RAND_F_RAND_DRBG_ENABLE_LOCKING,
801 RAND_R_DRBG_ALREADY_INITIALIZED);
805 if (drbg->lock == NULL) {
806 if (drbg->parent != NULL && drbg->parent->lock == NULL) {
807 RANDerr(RAND_F_RAND_DRBG_ENABLE_LOCKING,
808 RAND_R_PARENT_LOCKING_NOT_ENABLED);
812 drbg->lock = CRYPTO_THREAD_lock_new();
813 if (drbg->lock == NULL) {
814 RANDerr(RAND_F_RAND_DRBG_ENABLE_LOCKING,
815 RAND_R_FAILED_TO_CREATE_LOCK);
824 * Get and set the EXDATA
826 int RAND_DRBG_set_ex_data(RAND_DRBG *drbg, int idx, void *arg)
828 return CRYPTO_set_ex_data(&drbg->ex_data, idx, arg);
831 void *RAND_DRBG_get_ex_data(const RAND_DRBG *drbg, int idx)
833 return CRYPTO_get_ex_data(&drbg->ex_data, idx);
838 * The following functions provide a RAND_METHOD that works on the
839 * global DRBG. They lock.
843 * Allocates a new global DRBG on the secure heap (if enabled) and
844 * initializes it with default settings.
846 * Returns a pointer to the new DRBG instance on success, NULL on failure.
848 static RAND_DRBG *drbg_setup(RAND_DRBG *parent)
852 drbg = RAND_DRBG_secure_new(RAND_DRBG_NID, 0, parent);
856 if (rand_drbg_enable_locking(drbg) == 0)
859 /* enable seed propagation */
860 drbg->reseed_counter = 1;
863 * Ignore instantiation error so support just-in-time instantiation.
865 * The state of the drbg will be checked in RAND_DRBG_generate() and
866 * an automatic recovery is attempted.
868 RAND_DRBG_instantiate(drbg,
869 (const unsigned char *) ossl_pers_string,
870 sizeof(ossl_pers_string) - 1);
874 RAND_DRBG_free(drbg);
879 * Initialize the global DRBGs on first use.
880 * Returns 1 on success, 0 on failure.
882 DEFINE_RUN_ONCE_STATIC(do_rand_drbg_init)
885 * ensure that libcrypto is initialized, otherwise the
886 * DRBG locks are not cleaned up properly
888 if (!OPENSSL_init_crypto(0, NULL))
891 drbg_master = drbg_setup(NULL);
892 drbg_public = drbg_setup(drbg_master);
893 drbg_private = drbg_setup(drbg_master);
895 if (drbg_master == NULL || drbg_public == NULL || drbg_private == NULL)
901 /* Clean up the global DRBGs before exit */
902 void rand_drbg_cleanup_int(void)
904 RAND_DRBG_free(drbg_private);
905 RAND_DRBG_free(drbg_public);
906 RAND_DRBG_free(drbg_master);
908 drbg_private = drbg_public = drbg_master = NULL;
911 /* Implements the default OpenSSL RAND_bytes() method */
912 static int drbg_bytes(unsigned char *out, int count)
915 RAND_DRBG *drbg = RAND_DRBG_get0_public();
920 rand_drbg_lock(drbg);
921 ret = RAND_DRBG_bytes(drbg, out, count);
922 rand_drbg_unlock(drbg);
927 /* Implements the default OpenSSL RAND_add() method */
928 static int drbg_add(const void *buf, int num, double randomness)
931 RAND_DRBG *drbg = RAND_DRBG_get0_master();
936 if (num < 0 || randomness < 0.0)
939 if (randomness > (double)drbg->max_entropylen) {
941 * The purpose of this check is to bound |randomness| by a
942 * relatively small value in order to prevent an integer
943 * overflow when multiplying by 8 in the rand_drbg_restart()
949 rand_drbg_lock(drbg);
950 ret = rand_drbg_restart(drbg, buf,
951 (size_t)(unsigned int)num,
952 (size_t)(8*randomness));
953 rand_drbg_unlock(drbg);
958 /* Implements the default OpenSSL RAND_seed() method */
959 static int drbg_seed(const void *buf, int num)
961 return drbg_add(buf, num, num);
964 /* Implements the default OpenSSL RAND_status() method */
965 static int drbg_status(void)
968 RAND_DRBG *drbg = RAND_DRBG_get0_master();
973 rand_drbg_lock(drbg);
974 ret = drbg->state == DRBG_READY ? 1 : 0;
975 rand_drbg_unlock(drbg);
980 * Get the master DRBG.
981 * Returns pointer to the DRBG on success, NULL on failure.
984 RAND_DRBG *RAND_DRBG_get0_master(void)
986 if (!RUN_ONCE(&rand_drbg_init, do_rand_drbg_init))
993 * Get the public DRBG.
994 * Returns pointer to the DRBG on success, NULL on failure.
996 RAND_DRBG *RAND_DRBG_get0_public(void)
998 if (!RUN_ONCE(&rand_drbg_init, do_rand_drbg_init))
1005 * Get the private DRBG.
1006 * Returns pointer to the DRBG on success, NULL on failure.
1008 RAND_DRBG *RAND_DRBG_get0_private(void)
1010 if (!RUN_ONCE(&rand_drbg_init, do_rand_drbg_init))
1013 return drbg_private;
1016 RAND_METHOD rand_meth = {
1025 RAND_METHOD *RAND_OpenSSL(void)