2 * Copyright 2011-2018 The OpenSSL Project Authors. All Rights Reserved.
4 * Licensed under the OpenSSL license (the "License"). You may not use
5 * this file except in compliance with the License. You can obtain a copy
6 * in the file LICENSE in the source distribution or at
7 * https://www.openssl.org/source/license.html
11 #include <openssl/crypto.h>
12 #include <openssl/err.h>
13 #include <openssl/rand.h>
15 #include "internal/thread_once.h"
16 #include "internal/rand_int.h"
17 #include "internal/cryptlib_int.h"
20 * Support framework for NIST SP 800-90A DRBG
22 * See manual page RAND_DRBG(7) for a general overview.
24 * The OpenSSL model is to have new and free functions, and that new
25 * does all initialization. That is not the NIST model, which has
26 * instantiation and un-instantiate, and re-use within a new/free
27 * lifecycle. (No doubt this comes from the desire to support hardware
28 * DRBG, where allocation of resources on something like an HSM is
29 * a much bigger deal than just re-setting an allocated resource.)
33 * The three shared DRBG instances
35 * There are three shared DRBG instances: <master>, <public>, and <private>.
41 * Not used directly by the application, only for reseeding the two other
42 * DRBGs. It reseeds itself by pulling either randomness from os entropy
43 * sources or by consuming randomness which was added by RAND_add().
45 * The <master> DRBG is a global instance which is accessed concurrently by
46 * all threads. The necessary locking is managed automatically by its child
47 * DRBG instances during reseeding.
49 static RAND_DRBG
*master_drbg
;
53 * Used by default for generating random bytes using RAND_bytes().
55 * The <public> DRBG is thread-local, i.e., there is one instance per thread.
57 static CRYPTO_THREAD_LOCAL public_drbg
;
61 * Used by default for generating private keys using RAND_priv_bytes()
63 * The <private> DRBG is thread-local, i.e., there is one instance per thread.
65 static CRYPTO_THREAD_LOCAL private_drbg
;
69 /* NIST SP 800-90A DRBG recommends the use of a personalization string. */
70 static const char ossl_pers_string
[] = "OpenSSL NIST SP 800-90A DRBG";
72 static CRYPTO_ONCE rand_drbg_init
= CRYPTO_ONCE_STATIC_INIT
;
75 #define RAND_DRBG_TYPE_FLAGS ( \
76 RAND_DRBG_FLAG_MASTER | RAND_DRBG_FLAG_PUBLIC | RAND_DRBG_FLAG_PRIVATE )
78 #define RAND_DRBG_TYPE_MASTER 0
79 #define RAND_DRBG_TYPE_PUBLIC 1
80 #define RAND_DRBG_TYPE_PRIVATE 2
83 static int rand_drbg_type
[3] = {
84 RAND_DRBG_TYPE
, /* Master */
85 RAND_DRBG_TYPE
, /* Public */
86 RAND_DRBG_TYPE
/* Private */
88 static unsigned int rand_drbg_flags
[3] = {
89 RAND_DRBG_FLAGS
| RAND_DRBG_FLAG_MASTER
, /* Master */
90 RAND_DRBG_FLAGS
| RAND_DRBG_FLAG_PUBLIC
, /* Public */
91 RAND_DRBG_FLAGS
| RAND_DRBG_FLAG_PRIVATE
/* Private */
94 static unsigned int master_reseed_interval
= MASTER_RESEED_INTERVAL
;
95 static unsigned int slave_reseed_interval
= SLAVE_RESEED_INTERVAL
;
97 static time_t master_reseed_time_interval
= MASTER_RESEED_TIME_INTERVAL
;
98 static time_t slave_reseed_time_interval
= SLAVE_RESEED_TIME_INTERVAL
;
100 /* A logical OR of all used DRBG flag bits (currently there is only one) */
101 static const unsigned int rand_drbg_used_flags
=
102 RAND_DRBG_FLAG_CTR_NO_DF
| RAND_DRBG_FLAG_HMAC
| RAND_DRBG_TYPE_FLAGS
;
105 static RAND_DRBG
*drbg_setup(RAND_DRBG
*parent
, int drbg_type
);
107 static RAND_DRBG
*rand_drbg_new(int secure
,
112 static int is_ctr(int type
)
115 case NID_aes_128_ctr
:
116 case NID_aes_192_ctr
:
117 case NID_aes_256_ctr
:
124 static int is_digest(int type
)
145 * Set/initialize |drbg| to be of type |type|, with optional |flags|.
147 * If |type| and |flags| are zero, use the defaults
149 * Returns 1 on success, 0 on failure.
151 int RAND_DRBG_set(RAND_DRBG
*drbg
, int type
, unsigned int flags
)
155 if (type
== 0 && flags
== 0) {
156 type
= rand_drbg_type
[RAND_DRBG_TYPE_MASTER
];
157 flags
= rand_drbg_flags
[RAND_DRBG_TYPE_MASTER
];
160 /* If set is called multiple times - clear the old one */
161 if (type
!= drbg
->type
&& drbg
->type
!= 0 && drbg
->meth
!= NULL
) {
162 drbg
->meth
->uninstantiate(drbg
);
165 drbg
->state
= DRBG_UNINITIALISED
;
170 /* Uninitialized; that's okay. */
172 } else if (is_ctr(type
)) {
173 ret
= drbg_ctr_init(drbg
);
174 } else if (is_digest(type
)) {
175 if (flags
& RAND_DRBG_FLAG_HMAC
)
176 ret
= drbg_hmac_init(drbg
);
178 ret
= drbg_hash_init(drbg
);
180 RANDerr(RAND_F_RAND_DRBG_SET
, RAND_R_UNSUPPORTED_DRBG_TYPE
);
185 RANDerr(RAND_F_RAND_DRBG_SET
, RAND_R_ERROR_INITIALISING_DRBG
);
190 * Set/initialize default |type| and |flag| for new drbg instances.
192 * Returns 1 on success, 0 on failure.
194 int RAND_DRBG_set_defaults(int type
, unsigned int flags
)
197 if (!(is_digest(type
) || is_ctr(type
))) {
198 RANDerr(RAND_F_RAND_DRBG_SET_DEFAULTS
, RAND_R_UNSUPPORTED_DRBG_TYPE
);
202 if ((flags
& ~rand_drbg_used_flags
) != 0) {
203 RANDerr(RAND_F_RAND_DRBG_SET_DEFAULTS
, RAND_R_UNSUPPORTED_DRBG_FLAGS
);
207 all
= ((flags
& RAND_DRBG_TYPE_FLAGS
) == 0);
208 if (all
|| (flags
& RAND_DRBG_FLAG_MASTER
) != 0) {
209 rand_drbg_type
[RAND_DRBG_TYPE_MASTER
] = type
;
210 rand_drbg_flags
[RAND_DRBG_TYPE_MASTER
] = flags
| RAND_DRBG_FLAG_MASTER
;
212 if (all
|| (flags
& RAND_DRBG_FLAG_PUBLIC
) != 0) {
213 rand_drbg_type
[RAND_DRBG_TYPE_PUBLIC
] = type
;
214 rand_drbg_flags
[RAND_DRBG_TYPE_PUBLIC
] = flags
| RAND_DRBG_FLAG_PUBLIC
;
216 if (all
|| (flags
& RAND_DRBG_FLAG_PRIVATE
) != 0) {
217 rand_drbg_type
[RAND_DRBG_TYPE_PRIVATE
] = type
;
218 rand_drbg_flags
[RAND_DRBG_TYPE_PRIVATE
] = flags
| RAND_DRBG_FLAG_PRIVATE
;
225 * Allocate memory and initialize a new DRBG. The DRBG is allocated on
226 * the secure heap if |secure| is nonzero and the secure heap is enabled.
227 * The |parent|, if not NULL, will be used as random source for reseeding.
229 * Returns a pointer to the new DRBG instance on success, NULL on failure.
231 static RAND_DRBG
*rand_drbg_new(int secure
,
236 RAND_DRBG
*drbg
= secure
?
237 OPENSSL_secure_zalloc(sizeof(*drbg
)) : OPENSSL_zalloc(sizeof(*drbg
));
240 RANDerr(RAND_F_RAND_DRBG_NEW
, ERR_R_MALLOC_FAILURE
);
244 drbg
->secure
= secure
&& CRYPTO_secure_allocated(drbg
);
245 drbg
->fork_count
= rand_fork_count
;
246 drbg
->parent
= parent
;
248 if (parent
== NULL
) {
249 drbg
->get_entropy
= rand_drbg_get_entropy
;
250 drbg
->cleanup_entropy
= rand_drbg_cleanup_entropy
;
251 #ifndef RAND_DRBG_GET_RANDOM_NONCE
252 drbg
->get_nonce
= rand_drbg_get_nonce
;
253 drbg
->cleanup_nonce
= rand_drbg_cleanup_nonce
;
256 drbg
->reseed_interval
= master_reseed_interval
;
257 drbg
->reseed_time_interval
= master_reseed_time_interval
;
259 drbg
->get_entropy
= rand_drbg_get_entropy
;
260 drbg
->cleanup_entropy
= rand_drbg_cleanup_entropy
;
262 * Do not provide nonce callbacks, the child DRBGs will
263 * obtain their nonce using random bits from the parent.
266 drbg
->reseed_interval
= slave_reseed_interval
;
267 drbg
->reseed_time_interval
= slave_reseed_time_interval
;
270 if (RAND_DRBG_set(drbg
, type
, flags
) == 0)
273 if (parent
!= NULL
) {
274 rand_drbg_lock(parent
);
275 if (drbg
->strength
> parent
->strength
) {
277 * We currently don't support the algorithm from NIST SP 800-90C
278 * 10.1.2 to use a weaker DRBG as source
280 rand_drbg_unlock(parent
);
281 RANDerr(RAND_F_RAND_DRBG_NEW
, RAND_R_PARENT_STRENGTH_TOO_WEAK
);
284 rand_drbg_unlock(parent
);
291 OPENSSL_secure_free(drbg
);
298 RAND_DRBG
*RAND_DRBG_new(int type
, unsigned int flags
, RAND_DRBG
*parent
)
300 return rand_drbg_new(0, type
, flags
, parent
);
303 RAND_DRBG
*RAND_DRBG_secure_new(int type
, unsigned int flags
, RAND_DRBG
*parent
)
305 return rand_drbg_new(1, type
, flags
, parent
);
309 * Uninstantiate |drbg| and free all memory.
311 void RAND_DRBG_free(RAND_DRBG
*drbg
)
316 if (drbg
->meth
!= NULL
)
317 drbg
->meth
->uninstantiate(drbg
);
318 CRYPTO_THREAD_lock_free(drbg
->lock
);
319 CRYPTO_free_ex_data(CRYPTO_EX_INDEX_DRBG
, drbg
, &drbg
->ex_data
);
322 OPENSSL_secure_clear_free(drbg
, sizeof(*drbg
));
324 OPENSSL_clear_free(drbg
, sizeof(*drbg
));
328 * Instantiate |drbg|, after it has been initialized. Use |pers| and
329 * |perslen| as prediction-resistance input.
331 * Requires that drbg->lock is already locked for write, if non-null.
333 * Returns 1 on success, 0 on failure.
335 int RAND_DRBG_instantiate(RAND_DRBG
*drbg
,
336 const unsigned char *pers
, size_t perslen
)
338 unsigned char *nonce
= NULL
, *entropy
= NULL
;
339 size_t noncelen
= 0, entropylen
= 0;
340 size_t min_entropy
= drbg
->strength
;
341 size_t min_entropylen
= drbg
->min_entropylen
;
342 size_t max_entropylen
= drbg
->max_entropylen
;
344 if (perslen
> drbg
->max_perslen
) {
345 RANDerr(RAND_F_RAND_DRBG_INSTANTIATE
,
346 RAND_R_PERSONALISATION_STRING_TOO_LONG
);
350 if (drbg
->meth
== NULL
) {
351 RANDerr(RAND_F_RAND_DRBG_INSTANTIATE
,
352 RAND_R_NO_DRBG_IMPLEMENTATION_SELECTED
);
356 if (drbg
->state
!= DRBG_UNINITIALISED
) {
357 RANDerr(RAND_F_RAND_DRBG_INSTANTIATE
,
358 drbg
->state
== DRBG_ERROR
? RAND_R_IN_ERROR_STATE
359 : RAND_R_ALREADY_INSTANTIATED
);
363 drbg
->state
= DRBG_ERROR
;
366 * NIST SP800-90Ar1 section 9.1 says you can combine getting the entropy
367 * and nonce in 1 call by increasing the entropy with 50% and increasing
368 * the minimum length to accomadate the length of the nonce.
369 * We do this in case a nonce is require and get_nonce is NULL.
371 if (drbg
->min_noncelen
> 0 && drbg
->get_nonce
== NULL
) {
372 min_entropy
+= drbg
->strength
/ 2;
373 min_entropylen
+= drbg
->min_noncelen
;
374 max_entropylen
+= drbg
->max_noncelen
;
377 drbg
->reseed_next_counter
= tsan_load(&drbg
->reseed_prop_counter
);
378 if (drbg
->reseed_next_counter
) {
379 drbg
->reseed_next_counter
++;
380 if(!drbg
->reseed_next_counter
)
381 drbg
->reseed_next_counter
= 1;
384 if (drbg
->get_entropy
!= NULL
)
385 entropylen
= drbg
->get_entropy(drbg
, &entropy
, min_entropy
,
386 min_entropylen
, max_entropylen
, 0);
387 if (entropylen
< min_entropylen
388 || entropylen
> max_entropylen
) {
389 RANDerr(RAND_F_RAND_DRBG_INSTANTIATE
, RAND_R_ERROR_RETRIEVING_ENTROPY
);
393 if (drbg
->min_noncelen
> 0 && drbg
->get_nonce
!= NULL
) {
394 noncelen
= drbg
->get_nonce(drbg
, &nonce
, drbg
->strength
/ 2,
395 drbg
->min_noncelen
, drbg
->max_noncelen
);
396 if (noncelen
< drbg
->min_noncelen
|| noncelen
> drbg
->max_noncelen
) {
397 RANDerr(RAND_F_RAND_DRBG_INSTANTIATE
, RAND_R_ERROR_RETRIEVING_NONCE
);
402 if (!drbg
->meth
->instantiate(drbg
, entropy
, entropylen
,
403 nonce
, noncelen
, pers
, perslen
)) {
404 RANDerr(RAND_F_RAND_DRBG_INSTANTIATE
, RAND_R_ERROR_INSTANTIATING_DRBG
);
408 drbg
->state
= DRBG_READY
;
409 drbg
->reseed_gen_counter
= 1;
410 drbg
->reseed_time
= time(NULL
);
411 tsan_store(&drbg
->reseed_prop_counter
, drbg
->reseed_next_counter
);
414 if (entropy
!= NULL
&& drbg
->cleanup_entropy
!= NULL
)
415 drbg
->cleanup_entropy(drbg
, entropy
, entropylen
);
416 if (nonce
!= NULL
&& drbg
->cleanup_nonce
!= NULL
)
417 drbg
->cleanup_nonce(drbg
, nonce
, noncelen
);
418 if (drbg
->state
== DRBG_READY
)
424 * Uninstantiate |drbg|. Must be instantiated before it can be used.
426 * Requires that drbg->lock is already locked for write, if non-null.
428 * Returns 1 on success, 0 on failure.
430 int RAND_DRBG_uninstantiate(RAND_DRBG
*drbg
)
432 int index
= -1, type
, flags
;
433 if (drbg
->meth
== NULL
) {
434 RANDerr(RAND_F_RAND_DRBG_UNINSTANTIATE
,
435 RAND_R_NO_DRBG_IMPLEMENTATION_SELECTED
);
439 /* Clear the entire drbg->ctr struct, then reset some important
440 * members of the drbg->ctr struct (e.g. keysize, df_ks) to their
443 drbg
->meth
->uninstantiate(drbg
);
445 /* The reset uses the default values for type and flags */
446 if (drbg
->flags
& RAND_DRBG_FLAG_MASTER
)
447 index
= RAND_DRBG_TYPE_MASTER
;
448 else if (drbg
->flags
& RAND_DRBG_FLAG_PRIVATE
)
449 index
= RAND_DRBG_TYPE_PRIVATE
;
450 else if (drbg
->flags
& RAND_DRBG_FLAG_PUBLIC
)
451 index
= RAND_DRBG_TYPE_PUBLIC
;
454 flags
= rand_drbg_flags
[index
];
455 type
= rand_drbg_type
[index
];
460 return RAND_DRBG_set(drbg
, type
, flags
);
464 * Reseed |drbg|, mixing in the specified data
466 * Requires that drbg->lock is already locked for write, if non-null.
468 * Returns 1 on success, 0 on failure.
470 int RAND_DRBG_reseed(RAND_DRBG
*drbg
,
471 const unsigned char *adin
, size_t adinlen
,
472 int prediction_resistance
)
474 unsigned char *entropy
= NULL
;
475 size_t entropylen
= 0;
477 if (drbg
->state
== DRBG_ERROR
) {
478 RANDerr(RAND_F_RAND_DRBG_RESEED
, RAND_R_IN_ERROR_STATE
);
481 if (drbg
->state
== DRBG_UNINITIALISED
) {
482 RANDerr(RAND_F_RAND_DRBG_RESEED
, RAND_R_NOT_INSTANTIATED
);
488 } else if (adinlen
> drbg
->max_adinlen
) {
489 RANDerr(RAND_F_RAND_DRBG_RESEED
, RAND_R_ADDITIONAL_INPUT_TOO_LONG
);
493 drbg
->state
= DRBG_ERROR
;
495 drbg
->reseed_next_counter
= tsan_load(&drbg
->reseed_prop_counter
);
496 if (drbg
->reseed_next_counter
) {
497 drbg
->reseed_next_counter
++;
498 if(!drbg
->reseed_next_counter
)
499 drbg
->reseed_next_counter
= 1;
502 if (drbg
->get_entropy
!= NULL
)
503 entropylen
= drbg
->get_entropy(drbg
, &entropy
, drbg
->strength
,
504 drbg
->min_entropylen
,
505 drbg
->max_entropylen
,
506 prediction_resistance
);
507 if (entropylen
< drbg
->min_entropylen
508 || entropylen
> drbg
->max_entropylen
) {
509 RANDerr(RAND_F_RAND_DRBG_RESEED
, RAND_R_ERROR_RETRIEVING_ENTROPY
);
513 if (!drbg
->meth
->reseed(drbg
, entropy
, entropylen
, adin
, adinlen
))
516 drbg
->state
= DRBG_READY
;
517 drbg
->reseed_gen_counter
= 1;
518 drbg
->reseed_time
= time(NULL
);
519 tsan_store(&drbg
->reseed_prop_counter
, drbg
->reseed_next_counter
);
522 if (entropy
!= NULL
&& drbg
->cleanup_entropy
!= NULL
)
523 drbg
->cleanup_entropy(drbg
, entropy
, entropylen
);
524 if (drbg
->state
== DRBG_READY
)
530 * Restart |drbg|, using the specified entropy or additional input
532 * Tries its best to get the drbg instantiated by all means,
533 * regardless of its current state.
535 * Optionally, a |buffer| of |len| random bytes can be passed,
536 * which is assumed to contain at least |entropy| bits of entropy.
538 * If |entropy| > 0, the buffer content is used as entropy input.
540 * If |entropy| == 0, the buffer content is used as additional input
542 * Returns 1 on success, 0 on failure.
544 * This function is used internally only.
546 int rand_drbg_restart(RAND_DRBG
*drbg
,
547 const unsigned char *buffer
, size_t len
, size_t entropy
)
550 const unsigned char *adin
= NULL
;
553 if (drbg
->pool
!= NULL
) {
554 RANDerr(RAND_F_RAND_DRBG_RESTART
, ERR_R_INTERNAL_ERROR
);
555 drbg
->state
= DRBG_ERROR
;
556 rand_pool_free(drbg
->pool
);
561 if (buffer
!= NULL
) {
563 if (drbg
->max_entropylen
< len
) {
564 RANDerr(RAND_F_RAND_DRBG_RESTART
,
565 RAND_R_ENTROPY_INPUT_TOO_LONG
);
566 drbg
->state
= DRBG_ERROR
;
570 if (entropy
> 8 * len
) {
571 RANDerr(RAND_F_RAND_DRBG_RESTART
, RAND_R_ENTROPY_OUT_OF_RANGE
);
572 drbg
->state
= DRBG_ERROR
;
576 /* will be picked up by the rand_drbg_get_entropy() callback */
577 drbg
->pool
= rand_pool_attach(buffer
, len
, entropy
);
578 if (drbg
->pool
== NULL
)
581 if (drbg
->max_adinlen
< len
) {
582 RANDerr(RAND_F_RAND_DRBG_RESTART
,
583 RAND_R_ADDITIONAL_INPUT_TOO_LONG
);
584 drbg
->state
= DRBG_ERROR
;
592 /* repair error state */
593 if (drbg
->state
== DRBG_ERROR
)
594 RAND_DRBG_uninstantiate(drbg
);
596 /* repair uninitialized state */
597 if (drbg
->state
== DRBG_UNINITIALISED
) {
598 /* reinstantiate drbg */
599 RAND_DRBG_instantiate(drbg
,
600 (const unsigned char *) ossl_pers_string
,
601 sizeof(ossl_pers_string
) - 1);
602 /* already reseeded. prevent second reseeding below */
603 reseeded
= (drbg
->state
== DRBG_READY
);
606 /* refresh current state if entropy or additional input has been provided */
607 if (drbg
->state
== DRBG_READY
) {
610 * mix in additional input without reseeding
612 * Similar to RAND_DRBG_reseed(), but the provided additional
613 * data |adin| is mixed into the current state without pulling
614 * entropy from the trusted entropy source using get_entropy().
615 * This is not a reseeding in the strict sense of NIST SP 800-90A.
617 drbg
->meth
->reseed(drbg
, adin
, adinlen
, NULL
, 0);
618 } else if (reseeded
== 0) {
619 /* do a full reseeding if it has not been done yet above */
620 RAND_DRBG_reseed(drbg
, NULL
, 0, 0);
624 rand_pool_free(drbg
->pool
);
627 return drbg
->state
== DRBG_READY
;
631 * Generate |outlen| bytes into the buffer at |out|. Reseed if we need
632 * to or if |prediction_resistance| is set. Additional input can be
633 * sent in |adin| and |adinlen|.
635 * Requires that drbg->lock is already locked for write, if non-null.
637 * Returns 1 on success, 0 on failure.
640 int RAND_DRBG_generate(RAND_DRBG
*drbg
, unsigned char *out
, size_t outlen
,
641 int prediction_resistance
,
642 const unsigned char *adin
, size_t adinlen
)
644 int reseed_required
= 0;
646 if (drbg
->state
!= DRBG_READY
) {
647 /* try to recover from previous errors */
648 rand_drbg_restart(drbg
, NULL
, 0, 0);
650 if (drbg
->state
== DRBG_ERROR
) {
651 RANDerr(RAND_F_RAND_DRBG_GENERATE
, RAND_R_IN_ERROR_STATE
);
654 if (drbg
->state
== DRBG_UNINITIALISED
) {
655 RANDerr(RAND_F_RAND_DRBG_GENERATE
, RAND_R_NOT_INSTANTIATED
);
660 if (outlen
> drbg
->max_request
) {
661 RANDerr(RAND_F_RAND_DRBG_GENERATE
, RAND_R_REQUEST_TOO_LARGE_FOR_DRBG
);
664 if (adinlen
> drbg
->max_adinlen
) {
665 RANDerr(RAND_F_RAND_DRBG_GENERATE
, RAND_R_ADDITIONAL_INPUT_TOO_LONG
);
669 if (drbg
->fork_count
!= rand_fork_count
) {
670 drbg
->fork_count
= rand_fork_count
;
674 if (drbg
->reseed_interval
> 0) {
675 if (drbg
->reseed_gen_counter
> drbg
->reseed_interval
)
678 if (drbg
->reseed_time_interval
> 0) {
679 time_t now
= time(NULL
);
680 if (now
< drbg
->reseed_time
681 || now
- drbg
->reseed_time
>= drbg
->reseed_time_interval
)
684 if (drbg
->parent
!= NULL
) {
685 unsigned int reseed_counter
= tsan_load(&drbg
->reseed_prop_counter
);
686 if (reseed_counter
> 0
687 && tsan_load(&drbg
->parent
->reseed_prop_counter
)
692 if (reseed_required
|| prediction_resistance
) {
693 if (!RAND_DRBG_reseed(drbg
, adin
, adinlen
, prediction_resistance
)) {
694 RANDerr(RAND_F_RAND_DRBG_GENERATE
, RAND_R_RESEED_ERROR
);
701 if (!drbg
->meth
->generate(drbg
, out
, outlen
, adin
, adinlen
)) {
702 drbg
->state
= DRBG_ERROR
;
703 RANDerr(RAND_F_RAND_DRBG_GENERATE
, RAND_R_GENERATE_ERROR
);
707 drbg
->reseed_gen_counter
++;
713 * Generates |outlen| random bytes and stores them in |out|. It will
714 * using the given |drbg| to generate the bytes.
716 * Requires that drbg->lock is already locked for write, if non-null.
718 * Returns 1 on success 0 on failure.
720 int RAND_DRBG_bytes(RAND_DRBG
*drbg
, unsigned char *out
, size_t outlen
)
722 unsigned char *additional
= NULL
;
723 size_t additional_len
;
727 additional_len
= rand_drbg_get_additional_data(&additional
, drbg
->max_adinlen
);
729 for ( ; outlen
> 0; outlen
-= chunk
, out
+= chunk
) {
731 if (chunk
> drbg
->max_request
)
732 chunk
= drbg
->max_request
;
733 ret
= RAND_DRBG_generate(drbg
, out
, chunk
, 0, additional
, additional_len
);
740 if (additional_len
!= 0)
741 OPENSSL_secure_clear_free(additional
, additional_len
);
747 * Set the RAND_DRBG callbacks for obtaining entropy and nonce.
749 * Setting the callbacks is allowed only if the drbg has not been
750 * initialized yet. Otherwise, the operation will fail.
752 * Returns 1 on success, 0 on failure.
754 int RAND_DRBG_set_callbacks(RAND_DRBG
*drbg
,
755 RAND_DRBG_get_entropy_fn get_entropy
,
756 RAND_DRBG_cleanup_entropy_fn cleanup_entropy
,
757 RAND_DRBG_get_nonce_fn get_nonce
,
758 RAND_DRBG_cleanup_nonce_fn cleanup_nonce
)
760 if (drbg
->state
!= DRBG_UNINITIALISED
761 || drbg
->parent
!= NULL
)
763 drbg
->get_entropy
= get_entropy
;
764 drbg
->cleanup_entropy
= cleanup_entropy
;
765 drbg
->get_nonce
= get_nonce
;
766 drbg
->cleanup_nonce
= cleanup_nonce
;
771 * Set the reseed interval.
773 * The drbg will reseed automatically whenever the number of generate
774 * requests exceeds the given reseed interval. If the reseed interval
775 * is 0, then this feature is disabled.
777 * Returns 1 on success, 0 on failure.
779 int RAND_DRBG_set_reseed_interval(RAND_DRBG
*drbg
, unsigned int interval
)
781 if (interval
> MAX_RESEED_INTERVAL
)
783 drbg
->reseed_interval
= interval
;
788 * Set the reseed time interval.
790 * The drbg will reseed automatically whenever the time elapsed since
791 * the last reseeding exceeds the given reseed time interval. For safety,
792 * a reseeding will also occur if the clock has been reset to a smaller
795 * Returns 1 on success, 0 on failure.
797 int RAND_DRBG_set_reseed_time_interval(RAND_DRBG
*drbg
, time_t interval
)
799 if (interval
> MAX_RESEED_TIME_INTERVAL
)
801 drbg
->reseed_time_interval
= interval
;
806 * Set the default values for reseed (time) intervals of new DRBG instances
808 * The default values can be set independently for master DRBG instances
809 * (without a parent) and slave DRBG instances (with parent).
811 * Returns 1 on success, 0 on failure.
814 int RAND_DRBG_set_reseed_defaults(
815 unsigned int _master_reseed_interval
,
816 unsigned int _slave_reseed_interval
,
817 time_t _master_reseed_time_interval
,
818 time_t _slave_reseed_time_interval
821 if (_master_reseed_interval
> MAX_RESEED_INTERVAL
822 || _slave_reseed_interval
> MAX_RESEED_INTERVAL
)
825 if (_master_reseed_time_interval
> MAX_RESEED_TIME_INTERVAL
826 || _slave_reseed_time_interval
> MAX_RESEED_TIME_INTERVAL
)
829 master_reseed_interval
= _master_reseed_interval
;
830 slave_reseed_interval
= _slave_reseed_interval
;
832 master_reseed_time_interval
= _master_reseed_time_interval
;
833 slave_reseed_time_interval
= _slave_reseed_time_interval
;
839 * Locks the given drbg. Locking a drbg which does not have locking
840 * enabled is considered a successful no-op.
842 * Returns 1 on success, 0 on failure.
844 int rand_drbg_lock(RAND_DRBG
*drbg
)
846 if (drbg
->lock
!= NULL
)
847 return CRYPTO_THREAD_write_lock(drbg
->lock
);
853 * Unlocks the given drbg. Unlocking a drbg which does not have locking
854 * enabled is considered a successful no-op.
856 * Returns 1 on success, 0 on failure.
858 int rand_drbg_unlock(RAND_DRBG
*drbg
)
860 if (drbg
->lock
!= NULL
)
861 return CRYPTO_THREAD_unlock(drbg
->lock
);
867 * Enables locking for the given drbg
869 * Locking can only be enabled if the random generator
870 * is in the uninitialized state.
872 * Returns 1 on success, 0 on failure.
874 int rand_drbg_enable_locking(RAND_DRBG
*drbg
)
876 if (drbg
->state
!= DRBG_UNINITIALISED
) {
877 RANDerr(RAND_F_RAND_DRBG_ENABLE_LOCKING
,
878 RAND_R_DRBG_ALREADY_INITIALIZED
);
882 if (drbg
->lock
== NULL
) {
883 if (drbg
->parent
!= NULL
&& drbg
->parent
->lock
== NULL
) {
884 RANDerr(RAND_F_RAND_DRBG_ENABLE_LOCKING
,
885 RAND_R_PARENT_LOCKING_NOT_ENABLED
);
889 drbg
->lock
= CRYPTO_THREAD_lock_new();
890 if (drbg
->lock
== NULL
) {
891 RANDerr(RAND_F_RAND_DRBG_ENABLE_LOCKING
,
892 RAND_R_FAILED_TO_CREATE_LOCK
);
901 * Get and set the EXDATA
903 int RAND_DRBG_set_ex_data(RAND_DRBG
*drbg
, int idx
, void *arg
)
905 return CRYPTO_set_ex_data(&drbg
->ex_data
, idx
, arg
);
908 void *RAND_DRBG_get_ex_data(const RAND_DRBG
*drbg
, int idx
)
910 return CRYPTO_get_ex_data(&drbg
->ex_data
, idx
);
915 * The following functions provide a RAND_METHOD that works on the
916 * global DRBG. They lock.
920 * Allocates a new global DRBG on the secure heap (if enabled) and
921 * initializes it with default settings.
923 * Returns a pointer to the new DRBG instance on success, NULL on failure.
925 static RAND_DRBG
*drbg_setup(RAND_DRBG
*parent
, int drbg_type
)
929 drbg
= RAND_DRBG_secure_new(rand_drbg_type
[drbg_type
],
930 rand_drbg_flags
[drbg_type
], parent
);
934 /* Only the master DRBG needs to have a lock */
935 if (parent
== NULL
&& rand_drbg_enable_locking(drbg
) == 0)
938 /* enable seed propagation */
939 tsan_store(&drbg
->reseed_prop_counter
, 1);
942 * Ignore instantiation error to support just-in-time instantiation.
944 * The state of the drbg will be checked in RAND_DRBG_generate() and
945 * an automatic recovery is attempted.
947 (void)RAND_DRBG_instantiate(drbg
,
948 (const unsigned char *) ossl_pers_string
,
949 sizeof(ossl_pers_string
) - 1);
953 RAND_DRBG_free(drbg
);
958 * Initialize the global DRBGs on first use.
959 * Returns 1 on success, 0 on failure.
961 DEFINE_RUN_ONCE_STATIC(do_rand_drbg_init
)
964 * ensure that libcrypto is initialized, otherwise the
965 * DRBG locks are not cleaned up properly
967 if (!OPENSSL_init_crypto(0, NULL
))
970 if (!CRYPTO_THREAD_init_local(&private_drbg
, NULL
))
973 if (!CRYPTO_THREAD_init_local(&public_drbg
, NULL
))
976 master_drbg
= drbg_setup(NULL
, RAND_DRBG_TYPE_MASTER
);
977 if (master_drbg
== NULL
)
983 CRYPTO_THREAD_cleanup_local(&public_drbg
);
985 CRYPTO_THREAD_cleanup_local(&private_drbg
);
989 /* Clean up the global DRBGs before exit */
990 void rand_drbg_cleanup_int(void)
992 if (master_drbg
!= NULL
) {
993 RAND_DRBG_free(master_drbg
);
996 CRYPTO_THREAD_cleanup_local(&private_drbg
);
997 CRYPTO_THREAD_cleanup_local(&public_drbg
);
1001 void drbg_delete_thread_state(void)
1005 drbg
= CRYPTO_THREAD_get_local(&public_drbg
);
1006 CRYPTO_THREAD_set_local(&public_drbg
, NULL
);
1007 RAND_DRBG_free(drbg
);
1009 drbg
= CRYPTO_THREAD_get_local(&private_drbg
);
1010 CRYPTO_THREAD_set_local(&private_drbg
, NULL
);
1011 RAND_DRBG_free(drbg
);
1014 /* Implements the default OpenSSL RAND_bytes() method */
1015 static int drbg_bytes(unsigned char *out
, int count
)
1018 RAND_DRBG
*drbg
= RAND_DRBG_get0_public();
1023 ret
= RAND_DRBG_bytes(drbg
, out
, count
);
1029 * Calculates the minimum length of a full entropy buffer
1030 * which is necessary to seed (i.e. instantiate) the DRBG
1033 * NOTE: There is a copy of this function in drbgtest.c.
1034 * If you change anything here, you need to update
1035 * the copy accordingly.
1037 static size_t rand_drbg_seedlen(RAND_DRBG
*drbg
)
1040 * If no os entropy source is available then RAND_seed(buffer, bufsize)
1041 * is expected to succeed if and only if the buffer length satisfies
1042 * the following requirements, which follow from the calculations
1043 * in RAND_DRBG_instantiate().
1045 size_t min_entropy
= drbg
->strength
;
1046 size_t min_entropylen
= drbg
->min_entropylen
;
1049 * Extra entropy for the random nonce in the absence of a
1050 * get_nonce callback, see comment in RAND_DRBG_instantiate().
1052 if (drbg
->min_noncelen
> 0 && drbg
->get_nonce
== NULL
) {
1053 min_entropy
+= drbg
->strength
/ 2;
1054 min_entropylen
+= drbg
->min_noncelen
;
1058 * Convert entropy requirement from bits to bytes
1059 * (dividing by 8 without rounding upwards, because
1060 * all entropy requirements are divisible by 8).
1064 /* Return a value that satisfies both requirements */
1065 return min_entropy
> min_entropylen
? min_entropy
: min_entropylen
;
1068 /* Implements the default OpenSSL RAND_add() method */
1069 static int drbg_add(const void *buf
, int num
, double randomness
)
1072 RAND_DRBG
*drbg
= RAND_DRBG_get0_master();
1079 if (num
< 0 || randomness
< 0.0)
1082 seedlen
= rand_drbg_seedlen(drbg
);
1084 buflen
= (size_t)num
;
1086 if (buflen
< seedlen
|| randomness
< (double) seedlen
) {
1087 #if defined(OPENSSL_RAND_SEED_NONE)
1089 * If no os entropy source is available, a reseeding will fail
1090 * inevitably. So we use a trick to mix the buffer contents into
1091 * the DRBG state without forcing a reseeding: we generate a
1092 * dummy random byte, using the buffer content as additional data.
1094 unsigned char dummy
[1];
1096 return RAND_DRBG_generate(drbg
, dummy
, sizeof(dummy
), 0, buf
, buflen
);
1099 * If an os entropy source is avaible then we declare the buffer content
1100 * as additional data by setting randomness to zero and trigger a regular
1108 if (randomness
> (double)seedlen
) {
1110 * The purpose of this check is to bound |randomness| by a
1111 * relatively small value in order to prevent an integer
1112 * overflow when multiplying by 8 in the rand_drbg_restart()
1113 * call below. Note that randomness is measured in bytes,
1114 * not bits, so this value corresponds to eight times the
1115 * security strength.
1117 randomness
= (double)seedlen
;
1120 rand_drbg_lock(drbg
);
1121 ret
= rand_drbg_restart(drbg
, buf
, buflen
, (size_t)(8 * randomness
));
1122 rand_drbg_unlock(drbg
);
1127 /* Implements the default OpenSSL RAND_seed() method */
1128 static int drbg_seed(const void *buf
, int num
)
1130 return drbg_add(buf
, num
, num
);
1133 /* Implements the default OpenSSL RAND_status() method */
1134 static int drbg_status(void)
1137 RAND_DRBG
*drbg
= RAND_DRBG_get0_master();
1142 rand_drbg_lock(drbg
);
1143 ret
= drbg
->state
== DRBG_READY
? 1 : 0;
1144 rand_drbg_unlock(drbg
);
1149 * Get the master DRBG.
1150 * Returns pointer to the DRBG on success, NULL on failure.
1153 RAND_DRBG
*RAND_DRBG_get0_master(void)
1155 if (!RUN_ONCE(&rand_drbg_init
, do_rand_drbg_init
))
1162 * Get the public DRBG.
1163 * Returns pointer to the DRBG on success, NULL on failure.
1165 RAND_DRBG
*RAND_DRBG_get0_public(void)
1169 if (!RUN_ONCE(&rand_drbg_init
, do_rand_drbg_init
))
1172 drbg
= CRYPTO_THREAD_get_local(&public_drbg
);
1174 if (!ossl_init_thread_start(OPENSSL_INIT_THREAD_RAND
))
1176 drbg
= drbg_setup(master_drbg
, RAND_DRBG_TYPE_PUBLIC
);
1177 CRYPTO_THREAD_set_local(&public_drbg
, drbg
);
1183 * Get the private DRBG.
1184 * Returns pointer to the DRBG on success, NULL on failure.
1186 RAND_DRBG
*RAND_DRBG_get0_private(void)
1190 if (!RUN_ONCE(&rand_drbg_init
, do_rand_drbg_init
))
1193 drbg
= CRYPTO_THREAD_get_local(&private_drbg
);
1195 if (!ossl_init_thread_start(OPENSSL_INIT_THREAD_RAND
))
1197 drbg
= drbg_setup(master_drbg
, RAND_DRBG_TYPE_PRIVATE
);
1198 CRYPTO_THREAD_set_local(&private_drbg
, drbg
);
1203 RAND_METHOD rand_meth
= {
1212 RAND_METHOD
*RAND_OpenSSL(void)