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
;
118 static int rand_drbg_type
= RAND_DRBG_TYPE
;
119 static unsigned int rand_drbg_flags
= RAND_DRBG_FLAGS
;
121 static unsigned int master_reseed_interval
= MASTER_RESEED_INTERVAL
;
122 static unsigned int slave_reseed_interval
= SLAVE_RESEED_INTERVAL
;
124 static time_t master_reseed_time_interval
= MASTER_RESEED_TIME_INTERVAL
;
125 static time_t slave_reseed_time_interval
= SLAVE_RESEED_TIME_INTERVAL
;
127 static RAND_DRBG
*drbg_setup(RAND_DRBG
*parent
);
129 static RAND_DRBG
*rand_drbg_new(int secure
,
135 * Set/initialize |drbg| to be of type |type|, with optional |flags|.
137 * If |type| and |flags| are zero, use the defaults
139 * Returns 1 on success, 0 on failure.
141 int RAND_DRBG_set(RAND_DRBG
*drbg
, int type
, unsigned int flags
)
145 if (type
== 0 && flags
== 0) {
146 type
= rand_drbg_type
;
147 flags
= rand_drbg_flags
;
150 drbg
->state
= DRBG_UNINITIALISED
;
156 RANDerr(RAND_F_RAND_DRBG_SET
, RAND_R_UNSUPPORTED_DRBG_TYPE
);
159 /* Uninitialized; that's okay. */
161 case NID_aes_128_ctr
:
162 case NID_aes_192_ctr
:
163 case NID_aes_256_ctr
:
164 ret
= drbg_ctr_init(drbg
);
169 RANDerr(RAND_F_RAND_DRBG_SET
, RAND_R_ERROR_INITIALISING_DRBG
);
174 * Set/initialize default |type| and |flag| for new drbg instances.
176 * Returns 1 on success, 0 on failure.
178 int RAND_DRBG_set_defaults(int type
, unsigned int flags
)
184 RANDerr(RAND_F_RAND_DRBG_SET_DEFAULTS
, RAND_R_UNSUPPORTED_DRBG_TYPE
);
186 case NID_aes_128_ctr
:
187 case NID_aes_192_ctr
:
188 case NID_aes_256_ctr
:
192 if ((flags
& ~RAND_DRBG_USED_FLAGS
) != 0) {
193 RANDerr(RAND_F_RAND_DRBG_SET_DEFAULTS
, RAND_R_UNSUPPORTED_DRBG_FLAGS
);
197 rand_drbg_type
= type
;
198 rand_drbg_flags
= flags
;
205 * Allocate memory and initialize a new DRBG. The DRBG is allocated on
206 * the secure heap if |secure| is nonzero and the secure heap is enabled.
207 * The |parent|, if not NULL, will be used as random source for reseeding.
209 * Returns a pointer to the new DRBG instance on success, NULL on failure.
211 static RAND_DRBG
*rand_drbg_new(int secure
,
216 RAND_DRBG
*drbg
= secure
?
217 OPENSSL_secure_zalloc(sizeof(*drbg
)) : OPENSSL_zalloc(sizeof(*drbg
));
220 RANDerr(RAND_F_RAND_DRBG_NEW
, ERR_R_MALLOC_FAILURE
);
224 drbg
->secure
= secure
&& CRYPTO_secure_allocated(drbg
);
225 drbg
->fork_count
= rand_fork_count
;
226 drbg
->parent
= parent
;
228 if (parent
== NULL
) {
229 drbg
->reseed_interval
= master_reseed_interval
;
230 drbg
->reseed_time_interval
= master_reseed_time_interval
;
232 drbg
->reseed_interval
= slave_reseed_interval
;
233 drbg
->reseed_time_interval
= slave_reseed_time_interval
;
236 if (RAND_DRBG_set(drbg
, type
, flags
) == 0)
239 if (parent
!= NULL
&& drbg
->strength
> parent
->strength
) {
241 * We currently don't support the algorithm from NIST SP 800-90C
242 * 10.1.2 to use a weaker DRBG as source
244 RANDerr(RAND_F_RAND_DRBG_NEW
, RAND_R_PARENT_STRENGTH_TOO_WEAK
);
248 if (!RAND_DRBG_set_callbacks(drbg
, rand_drbg_get_entropy
,
249 rand_drbg_cleanup_entropy
,
257 OPENSSL_secure_free(drbg
);
264 RAND_DRBG
*RAND_DRBG_new(int type
, unsigned int flags
, RAND_DRBG
*parent
)
266 return rand_drbg_new(0, type
, flags
, parent
);
269 RAND_DRBG
*RAND_DRBG_secure_new(int type
, unsigned int flags
, RAND_DRBG
*parent
)
271 return rand_drbg_new(1, type
, flags
, parent
);
275 * Uninstantiate |drbg| and free all memory.
277 void RAND_DRBG_free(RAND_DRBG
*drbg
)
282 if (drbg
->meth
!= NULL
)
283 drbg
->meth
->uninstantiate(drbg
);
284 CRYPTO_THREAD_lock_free(drbg
->lock
);
285 CRYPTO_free_ex_data(CRYPTO_EX_INDEX_DRBG
, drbg
, &drbg
->ex_data
);
288 OPENSSL_secure_clear_free(drbg
, sizeof(*drbg
));
290 OPENSSL_clear_free(drbg
, sizeof(*drbg
));
294 * Instantiate |drbg|, after it has been initialized. Use |pers| and
295 * |perslen| as prediction-resistance input.
297 * Requires that drbg->lock is already locked for write, if non-null.
299 * Returns 1 on success, 0 on failure.
301 int RAND_DRBG_instantiate(RAND_DRBG
*drbg
,
302 const unsigned char *pers
, size_t perslen
)
304 unsigned char *nonce
= NULL
, *entropy
= NULL
;
305 size_t noncelen
= 0, entropylen
= 0;
307 if (perslen
> drbg
->max_perslen
) {
308 RANDerr(RAND_F_RAND_DRBG_INSTANTIATE
,
309 RAND_R_PERSONALISATION_STRING_TOO_LONG
);
313 if (drbg
->meth
== NULL
)
315 RANDerr(RAND_F_RAND_DRBG_INSTANTIATE
,
316 RAND_R_NO_DRBG_IMPLEMENTATION_SELECTED
);
320 if (drbg
->state
!= DRBG_UNINITIALISED
) {
321 RANDerr(RAND_F_RAND_DRBG_INSTANTIATE
,
322 drbg
->state
== DRBG_ERROR
? RAND_R_IN_ERROR_STATE
323 : RAND_R_ALREADY_INSTANTIATED
);
327 drbg
->state
= DRBG_ERROR
;
328 if (drbg
->get_entropy
!= NULL
)
329 entropylen
= drbg
->get_entropy(drbg
, &entropy
, drbg
->strength
,
330 drbg
->min_entropylen
, drbg
->max_entropylen
);
331 if (entropylen
< drbg
->min_entropylen
332 || entropylen
> drbg
->max_entropylen
) {
333 RANDerr(RAND_F_RAND_DRBG_INSTANTIATE
, RAND_R_ERROR_RETRIEVING_ENTROPY
);
337 if (drbg
->max_noncelen
> 0 && drbg
->get_nonce
!= NULL
) {
338 noncelen
= drbg
->get_nonce(drbg
, &nonce
, drbg
->strength
/ 2,
339 drbg
->min_noncelen
, drbg
->max_noncelen
);
340 if (noncelen
< drbg
->min_noncelen
|| noncelen
> drbg
->max_noncelen
) {
341 RANDerr(RAND_F_RAND_DRBG_INSTANTIATE
,
342 RAND_R_ERROR_RETRIEVING_NONCE
);
347 if (!drbg
->meth
->instantiate(drbg
, entropy
, entropylen
,
348 nonce
, noncelen
, pers
, perslen
)) {
349 RANDerr(RAND_F_RAND_DRBG_INSTANTIATE
, RAND_R_ERROR_INSTANTIATING_DRBG
);
353 drbg
->state
= DRBG_READY
;
354 drbg
->generate_counter
= 0;
355 drbg
->reseed_time
= time(NULL
);
356 if (drbg
->reseed_counter
> 0) {
357 if (drbg
->parent
== NULL
)
358 drbg
->reseed_counter
++;
360 drbg
->reseed_counter
= drbg
->parent
->reseed_counter
;
364 if (entropy
!= NULL
&& drbg
->cleanup_entropy
!= NULL
)
365 drbg
->cleanup_entropy(drbg
, entropy
, entropylen
);
366 if (nonce
!= NULL
&& drbg
->cleanup_nonce
!= NULL
)
367 drbg
->cleanup_nonce(drbg
, nonce
, noncelen
);
368 if (drbg
->pool
!= NULL
) {
369 if (drbg
->state
== DRBG_READY
) {
370 RANDerr(RAND_F_RAND_DRBG_INSTANTIATE
,
371 RAND_R_ERROR_ENTROPY_POOL_WAS_IGNORED
);
372 drbg
->state
= DRBG_ERROR
;
374 rand_pool_free(drbg
->pool
);
377 if (drbg
->state
== DRBG_READY
)
383 * Uninstantiate |drbg|. Must be instantiated before it can be used.
385 * Requires that drbg->lock is already locked for write, if non-null.
387 * Returns 1 on success, 0 on failure.
389 int RAND_DRBG_uninstantiate(RAND_DRBG
*drbg
)
391 if (drbg
->meth
== NULL
)
393 RANDerr(RAND_F_RAND_DRBG_UNINSTANTIATE
,
394 RAND_R_NO_DRBG_IMPLEMENTATION_SELECTED
);
398 /* Clear the entire drbg->ctr struct, then reset some important
399 * members of the drbg->ctr struct (e.g. keysize, df_ks) to their
402 drbg
->meth
->uninstantiate(drbg
);
403 return RAND_DRBG_set(drbg
, drbg
->type
, drbg
->flags
);
407 * Reseed |drbg|, mixing in the specified data
409 * Requires that drbg->lock is already locked for write, if non-null.
411 * Returns 1 on success, 0 on failure.
413 int RAND_DRBG_reseed(RAND_DRBG
*drbg
,
414 const unsigned char *adin
, size_t adinlen
)
416 unsigned char *entropy
= NULL
;
417 size_t entropylen
= 0;
419 if (drbg
->state
== DRBG_ERROR
) {
420 RANDerr(RAND_F_RAND_DRBG_RESEED
, RAND_R_IN_ERROR_STATE
);
423 if (drbg
->state
== DRBG_UNINITIALISED
) {
424 RANDerr(RAND_F_RAND_DRBG_RESEED
, RAND_R_NOT_INSTANTIATED
);
430 else if (adinlen
> drbg
->max_adinlen
) {
431 RANDerr(RAND_F_RAND_DRBG_RESEED
, RAND_R_ADDITIONAL_INPUT_TOO_LONG
);
435 drbg
->state
= DRBG_ERROR
;
436 if (drbg
->get_entropy
!= NULL
)
437 entropylen
= drbg
->get_entropy(drbg
, &entropy
, drbg
->strength
,
438 drbg
->min_entropylen
, drbg
->max_entropylen
);
439 if (entropylen
< drbg
->min_entropylen
440 || entropylen
> drbg
->max_entropylen
) {
441 RANDerr(RAND_F_RAND_DRBG_RESEED
, RAND_R_ERROR_RETRIEVING_ENTROPY
);
445 if (!drbg
->meth
->reseed(drbg
, entropy
, entropylen
, adin
, adinlen
))
448 drbg
->state
= DRBG_READY
;
449 drbg
->generate_counter
= 0;
450 drbg
->reseed_time
= time(NULL
);
451 if (drbg
->reseed_counter
> 0) {
452 if (drbg
->parent
== NULL
)
453 drbg
->reseed_counter
++;
455 drbg
->reseed_counter
= drbg
->parent
->reseed_counter
;
459 if (entropy
!= NULL
&& drbg
->cleanup_entropy
!= NULL
)
460 drbg
->cleanup_entropy(drbg
, entropy
, entropylen
);
461 if (drbg
->state
== DRBG_READY
)
467 * Restart |drbg|, using the specified entropy or additional input
469 * Tries its best to get the drbg instantiated by all means,
470 * regardless of its current state.
472 * Optionally, a |buffer| of |len| random bytes can be passed,
473 * which is assumed to contain at least |entropy| bits of entropy.
475 * If |entropy| > 0, the buffer content is used as entropy input.
477 * If |entropy| == 0, the buffer content is used as additional input
479 * Returns 1 on success, 0 on failure.
481 * This function is used internally only.
483 int rand_drbg_restart(RAND_DRBG
*drbg
,
484 const unsigned char *buffer
, size_t len
, size_t entropy
)
487 const unsigned char *adin
= NULL
;
490 if (drbg
->pool
!= NULL
) {
491 RANDerr(RAND_F_RAND_DRBG_RESTART
, ERR_R_INTERNAL_ERROR
);
492 rand_pool_free(drbg
->pool
);
496 if (buffer
!= NULL
) {
498 if (drbg
->max_entropylen
< len
) {
499 RANDerr(RAND_F_RAND_DRBG_RESTART
,
500 RAND_R_ENTROPY_INPUT_TOO_LONG
);
504 if (entropy
> 8 * len
) {
505 RANDerr(RAND_F_RAND_DRBG_RESTART
, RAND_R_ENTROPY_OUT_OF_RANGE
);
509 /* will be picked up by the rand_drbg_get_entropy() callback */
510 drbg
->pool
= rand_pool_new(entropy
, len
, len
);
511 if (drbg
->pool
== NULL
)
514 rand_pool_add(drbg
->pool
, buffer
, len
, entropy
);
516 if (drbg
->max_adinlen
< len
) {
517 RANDerr(RAND_F_RAND_DRBG_RESTART
,
518 RAND_R_ADDITIONAL_INPUT_TOO_LONG
);
526 /* repair error state */
527 if (drbg
->state
== DRBG_ERROR
)
528 RAND_DRBG_uninstantiate(drbg
);
530 /* repair uninitialized state */
531 if (drbg
->state
== DRBG_UNINITIALISED
) {
532 /* reinstantiate drbg */
533 RAND_DRBG_instantiate(drbg
,
534 (const unsigned char *) ossl_pers_string
,
535 sizeof(ossl_pers_string
) - 1);
536 /* already reseeded. prevent second reseeding below */
537 reseeded
= (drbg
->state
== DRBG_READY
);
540 /* refresh current state if entropy or additional input has been provided */
541 if (drbg
->state
== DRBG_READY
) {
544 * mix in additional input without reseeding
546 * Similar to RAND_DRBG_reseed(), but the provided additional
547 * data |adin| is mixed into the current state without pulling
548 * entropy from the trusted entropy source using get_entropy().
549 * This is not a reseeding in the strict sense of NIST SP 800-90A.
551 drbg
->meth
->reseed(drbg
, adin
, adinlen
, NULL
, 0);
552 } else if (reseeded
== 0) {
553 /* do a full reseeding if it has not been done yet above */
554 RAND_DRBG_reseed(drbg
, NULL
, 0);
558 /* check whether a given entropy pool was cleared properly during reseed */
559 if (drbg
->pool
!= NULL
) {
560 drbg
->state
= DRBG_ERROR
;
561 RANDerr(RAND_F_RAND_DRBG_RESTART
, ERR_R_INTERNAL_ERROR
);
562 rand_pool_free(drbg
->pool
);
567 return drbg
->state
== DRBG_READY
;
571 * Generate |outlen| bytes into the buffer at |out|. Reseed if we need
572 * to or if |prediction_resistance| is set. Additional input can be
573 * sent in |adin| and |adinlen|.
575 * Requires that drbg->lock is already locked for write, if non-null.
577 * Returns 1 on success, 0 on failure.
580 int RAND_DRBG_generate(RAND_DRBG
*drbg
, unsigned char *out
, size_t outlen
,
581 int prediction_resistance
,
582 const unsigned char *adin
, size_t adinlen
)
584 int reseed_required
= 0;
586 if (drbg
->state
!= DRBG_READY
) {
587 /* try to recover from previous errors */
588 rand_drbg_restart(drbg
, NULL
, 0, 0);
590 if (drbg
->state
== DRBG_ERROR
) {
591 RANDerr(RAND_F_RAND_DRBG_GENERATE
, RAND_R_IN_ERROR_STATE
);
594 if (drbg
->state
== DRBG_UNINITIALISED
) {
595 RANDerr(RAND_F_RAND_DRBG_GENERATE
, RAND_R_NOT_INSTANTIATED
);
600 if (outlen
> drbg
->max_request
) {
601 RANDerr(RAND_F_RAND_DRBG_GENERATE
, RAND_R_REQUEST_TOO_LARGE_FOR_DRBG
);
604 if (adinlen
> drbg
->max_adinlen
) {
605 RANDerr(RAND_F_RAND_DRBG_GENERATE
, RAND_R_ADDITIONAL_INPUT_TOO_LONG
);
609 if (drbg
->fork_count
!= rand_fork_count
) {
610 drbg
->fork_count
= rand_fork_count
;
614 if (drbg
->reseed_interval
> 0) {
615 if (drbg
->generate_counter
>= drbg
->reseed_interval
)
618 if (drbg
->reseed_time_interval
> 0) {
619 time_t now
= time(NULL
);
620 if (now
< drbg
->reseed_time
621 || now
- drbg
->reseed_time
>= drbg
->reseed_time_interval
)
624 if (drbg
->reseed_counter
> 0 && drbg
->parent
!= NULL
) {
625 if (drbg
->reseed_counter
!= drbg
->parent
->reseed_counter
)
629 if (reseed_required
|| prediction_resistance
) {
630 if (!RAND_DRBG_reseed(drbg
, adin
, adinlen
)) {
631 RANDerr(RAND_F_RAND_DRBG_GENERATE
, RAND_R_RESEED_ERROR
);
638 if (!drbg
->meth
->generate(drbg
, out
, outlen
, adin
, adinlen
)) {
639 drbg
->state
= DRBG_ERROR
;
640 RANDerr(RAND_F_RAND_DRBG_GENERATE
, RAND_R_GENERATE_ERROR
);
644 drbg
->generate_counter
++;
650 * Generates |outlen| random bytes and stores them in |out|. It will
651 * using the given |drbg| to generate the bytes.
653 * Requires that drbg->lock is already locked for write, if non-null.
655 * Returns 1 on success 0 on failure.
657 int RAND_DRBG_bytes(RAND_DRBG
*drbg
, unsigned char *out
, size_t outlen
)
659 unsigned char *additional
= NULL
;
660 size_t additional_len
;
664 additional_len
= rand_drbg_get_additional_data(&additional
, drbg
->max_adinlen
);
666 for ( ; outlen
> 0; outlen
-= chunk
, out
+= chunk
) {
668 if (chunk
> drbg
->max_request
)
669 chunk
= drbg
->max_request
;
670 ret
= RAND_DRBG_generate(drbg
, out
, chunk
, 0, additional
, additional_len
);
677 if (additional_len
!= 0)
678 OPENSSL_secure_clear_free(additional
, additional_len
);
684 * Set the RAND_DRBG callbacks for obtaining entropy and nonce.
686 * In the following, the signature and the semantics of the
687 * get_entropy() and cleanup_entropy() callbacks are explained.
691 * size_t get_entropy(RAND_DRBG *ctx,
692 * unsigned char **pout,
694 * size_t min_len, size_t max_len);
696 * This is a request to allocate and fill a buffer of size
697 * |min_len| <= size <= |max_len| (in bytes) which contains
698 * at least |entropy| bits of randomness. The buffer's address is
699 * to be returned in |*pout| and the number of collected
700 * randomness bytes (which may be less than the allocated size
701 * of the buffer) as return value.
703 * If the callback fails to acquire at least |entropy| bits of
704 * randomness, it shall return a buffer length of 0.
708 * void cleanup_entropy(RAND_DRBG *ctx,
709 * unsigned char *out, size_t outlen);
711 * A request to clear and free the buffer allocated by get_entropy().
712 * The values |out| and |outlen| are expected to be the random buffer's
713 * address and length, as returned by the get_entropy() callback.
715 * GET_NONCE, CLEANUP_NONCE
717 * Signature and semantics of the get_nonce() and cleanup_nonce()
718 * callbacks are analogous to get_entropy() and cleanup_entropy().
719 * Currently, the nonce is used only for the known answer tests.
721 int RAND_DRBG_set_callbacks(RAND_DRBG
*drbg
,
722 RAND_DRBG_get_entropy_fn get_entropy
,
723 RAND_DRBG_cleanup_entropy_fn cleanup_entropy
,
724 RAND_DRBG_get_nonce_fn get_nonce
,
725 RAND_DRBG_cleanup_nonce_fn cleanup_nonce
)
727 if (drbg
->state
!= DRBG_UNINITIALISED
)
729 drbg
->get_entropy
= get_entropy
;
730 drbg
->cleanup_entropy
= cleanup_entropy
;
731 drbg
->get_nonce
= get_nonce
;
732 drbg
->cleanup_nonce
= cleanup_nonce
;
737 * Set the reseed interval.
739 * The drbg will reseed automatically whenever the number of generate
740 * requests exceeds the given reseed interval. If the reseed interval
741 * is 0, then this feature is disabled.
743 * Returns 1 on success, 0 on failure.
745 int RAND_DRBG_set_reseed_interval(RAND_DRBG
*drbg
, unsigned int interval
)
747 if (interval
> MAX_RESEED_INTERVAL
)
749 drbg
->reseed_interval
= interval
;
754 * Set the reseed time interval.
756 * The drbg will reseed automatically whenever the time elapsed since
757 * the last reseeding exceeds the given reseed time interval. For safety,
758 * a reseeding will also occur if the clock has been reset to a smaller
761 * Returns 1 on success, 0 on failure.
763 int RAND_DRBG_set_reseed_time_interval(RAND_DRBG
*drbg
, time_t interval
)
765 if (interval
> MAX_RESEED_TIME_INTERVAL
)
767 drbg
->reseed_time_interval
= interval
;
772 * Set the default values for reseed (time) intervals of new DRBG instances
774 * The default values can be set independently for master DRBG instances
775 * (without a parent) and slave DRBG instances (with parent).
777 * Returns 1 on success, 0 on failure.
780 int RAND_DRBG_set_reseed_defaults(
781 unsigned int _master_reseed_interval
,
782 unsigned int _slave_reseed_interval
,
783 time_t _master_reseed_time_interval
,
784 time_t _slave_reseed_time_interval
787 if (_master_reseed_interval
> MAX_RESEED_INTERVAL
788 || _slave_reseed_interval
> MAX_RESEED_INTERVAL
)
791 if (_master_reseed_time_interval
> MAX_RESEED_TIME_INTERVAL
792 || _slave_reseed_time_interval
> MAX_RESEED_TIME_INTERVAL
)
795 master_reseed_interval
= _master_reseed_interval
;
796 slave_reseed_interval
= _slave_reseed_interval
;
798 master_reseed_time_interval
= _master_reseed_time_interval
;
799 slave_reseed_time_interval
= _slave_reseed_time_interval
;
805 * Locks the given drbg. Locking a drbg which does not have locking
806 * enabled is considered a successful no-op.
808 * Returns 1 on success, 0 on failure.
810 int rand_drbg_lock(RAND_DRBG
*drbg
)
812 if (drbg
->lock
!= NULL
)
813 return CRYPTO_THREAD_write_lock(drbg
->lock
);
819 * Unlocks the given drbg. Unlocking a drbg which does not have locking
820 * enabled is considered a successful no-op.
822 * Returns 1 on success, 0 on failure.
824 int rand_drbg_unlock(RAND_DRBG
*drbg
)
826 if (drbg
->lock
!= NULL
)
827 return CRYPTO_THREAD_unlock(drbg
->lock
);
833 * Enables locking for the given drbg
835 * Locking can only be enabled if the random generator
836 * is in the uninitialized state.
838 * Returns 1 on success, 0 on failure.
840 int rand_drbg_enable_locking(RAND_DRBG
*drbg
)
842 if (drbg
->state
!= DRBG_UNINITIALISED
) {
843 RANDerr(RAND_F_RAND_DRBG_ENABLE_LOCKING
,
844 RAND_R_DRBG_ALREADY_INITIALIZED
);
848 if (drbg
->lock
== NULL
) {
849 if (drbg
->parent
!= NULL
&& drbg
->parent
->lock
== NULL
) {
850 RANDerr(RAND_F_RAND_DRBG_ENABLE_LOCKING
,
851 RAND_R_PARENT_LOCKING_NOT_ENABLED
);
855 drbg
->lock
= CRYPTO_THREAD_lock_new();
856 if (drbg
->lock
== NULL
) {
857 RANDerr(RAND_F_RAND_DRBG_ENABLE_LOCKING
,
858 RAND_R_FAILED_TO_CREATE_LOCK
);
867 * Get and set the EXDATA
869 int RAND_DRBG_set_ex_data(RAND_DRBG
*drbg
, int idx
, void *arg
)
871 return CRYPTO_set_ex_data(&drbg
->ex_data
, idx
, arg
);
874 void *RAND_DRBG_get_ex_data(const RAND_DRBG
*drbg
, int idx
)
876 return CRYPTO_get_ex_data(&drbg
->ex_data
, idx
);
881 * The following functions provide a RAND_METHOD that works on the
882 * global DRBG. They lock.
886 * Allocates a new global DRBG on the secure heap (if enabled) and
887 * initializes it with default settings.
889 * Returns a pointer to the new DRBG instance on success, NULL on failure.
891 static RAND_DRBG
*drbg_setup(RAND_DRBG
*parent
)
895 drbg
= RAND_DRBG_secure_new(rand_drbg_type
, rand_drbg_flags
, parent
);
899 if (rand_drbg_enable_locking(drbg
) == 0)
902 /* enable seed propagation */
903 drbg
->reseed_counter
= 1;
906 * Ignore instantiation error so support just-in-time instantiation.
908 * The state of the drbg will be checked in RAND_DRBG_generate() and
909 * an automatic recovery is attempted.
911 RAND_DRBG_instantiate(drbg
,
912 (const unsigned char *) ossl_pers_string
,
913 sizeof(ossl_pers_string
) - 1);
917 RAND_DRBG_free(drbg
);
922 * Initialize the global DRBGs on first use.
923 * Returns 1 on success, 0 on failure.
925 DEFINE_RUN_ONCE_STATIC(do_rand_drbg_init
)
928 * ensure that libcrypto is initialized, otherwise the
929 * DRBG locks are not cleaned up properly
931 if (!OPENSSL_init_crypto(0, NULL
))
934 drbg_master
= drbg_setup(NULL
);
935 drbg_public
= drbg_setup(drbg_master
);
936 drbg_private
= drbg_setup(drbg_master
);
938 if (drbg_master
== NULL
|| drbg_public
== NULL
|| drbg_private
== NULL
)
944 /* Clean up the global DRBGs before exit */
945 void rand_drbg_cleanup_int(void)
947 RAND_DRBG_free(drbg_private
);
948 RAND_DRBG_free(drbg_public
);
949 RAND_DRBG_free(drbg_master
);
951 drbg_private
= drbg_public
= drbg_master
= NULL
;
954 /* Implements the default OpenSSL RAND_bytes() method */
955 static int drbg_bytes(unsigned char *out
, int count
)
958 RAND_DRBG
*drbg
= RAND_DRBG_get0_public();
963 rand_drbg_lock(drbg
);
964 ret
= RAND_DRBG_bytes(drbg
, out
, count
);
965 rand_drbg_unlock(drbg
);
970 /* Implements the default OpenSSL RAND_add() method */
971 static int drbg_add(const void *buf
, int num
, double randomness
)
974 RAND_DRBG
*drbg
= RAND_DRBG_get0_master();
979 if (num
< 0 || randomness
< 0.0)
982 if (randomness
> (double)drbg
->max_entropylen
) {
984 * The purpose of this check is to bound |randomness| by a
985 * relatively small value in order to prevent an integer
986 * overflow when multiplying by 8 in the rand_drbg_restart()
992 rand_drbg_lock(drbg
);
993 ret
= rand_drbg_restart(drbg
, buf
,
994 (size_t)(unsigned int)num
,
995 (size_t)(8*randomness
));
996 rand_drbg_unlock(drbg
);
1001 /* Implements the default OpenSSL RAND_seed() method */
1002 static int drbg_seed(const void *buf
, int num
)
1004 return drbg_add(buf
, num
, num
);
1007 /* Implements the default OpenSSL RAND_status() method */
1008 static int drbg_status(void)
1011 RAND_DRBG
*drbg
= RAND_DRBG_get0_master();
1016 rand_drbg_lock(drbg
);
1017 ret
= drbg
->state
== DRBG_READY
? 1 : 0;
1018 rand_drbg_unlock(drbg
);
1023 * Get the master DRBG.
1024 * Returns pointer to the DRBG on success, NULL on failure.
1027 RAND_DRBG
*RAND_DRBG_get0_master(void)
1029 if (!RUN_ONCE(&rand_drbg_init
, do_rand_drbg_init
))
1036 * Get the public DRBG.
1037 * Returns pointer to the DRBG on success, NULL on failure.
1039 RAND_DRBG
*RAND_DRBG_get0_public(void)
1041 if (!RUN_ONCE(&rand_drbg_init
, do_rand_drbg_init
))
1048 * Get the private DRBG.
1049 * Returns pointer to the DRBG on success, NULL on failure.
1051 RAND_DRBG
*RAND_DRBG_get0_private(void)
1053 if (!RUN_ONCE(&rand_drbg_init
, do_rand_drbg_init
))
1056 return drbg_private
;
1059 RAND_METHOD rand_meth
= {
1068 RAND_METHOD
*RAND_OpenSSL(void)