5d6ea1e26e5bab3b0ecd525162e4d87532ae6063
[openssl.git] / crypto / rand / drbg_lib.c
1 /*
2  * Copyright 2011-2018 The OpenSSL Project Authors. All Rights Reserved.
3  *
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
8  */
9
10 #include <string.h>
11 #include <openssl/crypto.h>
12 #include <openssl/err.h>
13 #include <openssl/rand.h>
14 #include "rand_lcl.h"
15 #include "internal/thread_once.h"
16 #include "internal/rand_int.h"
17 #include "internal/cryptlib_int.h"
18
19 /*
20  * Support framework for NIST SP 800-90A DRBG
21  *
22  * See manual page RAND_DRBG(7) for a general overview.
23  *
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.)
30  */
31
32
33 typedef struct drbg_global_st {
34     /*
35      * The three shared DRBG instances
36      *
37      * There are three shared DRBG instances: <master>, <public>, and <private>.
38      */
39
40     /*
41      * The <master> DRBG
42      *
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().
46      *
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.
50      */
51     RAND_DRBG *master_drbg;
52     /*
53      * The <public> DRBG
54      *
55      * Used by default for generating random bytes using RAND_bytes().
56      *
57      * The <public> DRBG is thread-local, i.e., there is one instance per
58      * thread.
59      */
60     CRYPTO_THREAD_LOCAL public_drbg;
61     /*
62      * The <private> DRBG
63      *
64      * Used by default for generating private keys using RAND_priv_bytes()
65      *
66      * The <private> DRBG is thread-local, i.e., there is one instance per
67      * thread.
68      */
69     CRYPTO_THREAD_LOCAL private_drbg;
70 } DRBG_GLOBAL;
71
72 typedef struct drbg_nonce_global_st {
73     CRYPTO_RWLOCK *rand_nonce_lock;
74     int rand_nonce_count;
75 } DRBG_NONCE_GLOBAL;
76
77 /* NIST SP 800-90A DRBG recommends the use of a personalization string. */
78 static const char ossl_pers_string[] = DRBG_DEFAULT_PERS_STRING;
79
80 #define RAND_DRBG_TYPE_FLAGS    ( \
81     RAND_DRBG_FLAG_MASTER | RAND_DRBG_FLAG_PUBLIC | RAND_DRBG_FLAG_PRIVATE )
82
83 #define RAND_DRBG_TYPE_MASTER                     0
84 #define RAND_DRBG_TYPE_PUBLIC                     1
85 #define RAND_DRBG_TYPE_PRIVATE                    2
86
87 /* Defaults */
88 static int rand_drbg_type[3] = {
89     RAND_DRBG_TYPE, /* Master */
90     RAND_DRBG_TYPE, /* Public */
91     RAND_DRBG_TYPE  /* Private */
92 };
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 */
97 };
98
99 static unsigned int master_reseed_interval = MASTER_RESEED_INTERVAL;
100 static unsigned int slave_reseed_interval  = SLAVE_RESEED_INTERVAL;
101
102 static time_t master_reseed_time_interval = MASTER_RESEED_TIME_INTERVAL;
103 static time_t slave_reseed_time_interval  = SLAVE_RESEED_TIME_INTERVAL;
104
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;
108
109
110 static RAND_DRBG *drbg_setup(OPENSSL_CTX *ctx, RAND_DRBG *parent, int drbg_type);
111
112 static RAND_DRBG *rand_drbg_new(OPENSSL_CTX *ctx,
113                                 int secure,
114                                 int type,
115                                 unsigned int flags,
116                                 RAND_DRBG *parent);
117
118 static int is_ctr(int type)
119 {
120     switch (type) {
121     case NID_aes_128_ctr:
122     case NID_aes_192_ctr:
123     case NID_aes_256_ctr:
124         return 1;
125     default:
126         return 0;
127     }
128 }
129
130 static int is_digest(int type)
131 {
132     switch (type) {
133     case NID_sha1:
134     case NID_sha224:
135     case NID_sha256:
136     case NID_sha384:
137     case NID_sha512:
138     case NID_sha512_224:
139     case NID_sha512_256:
140     case NID_sha3_224:
141     case NID_sha3_256:
142     case NID_sha3_384:
143     case NID_sha3_512:
144         return 1;
145     default:
146         return 0;
147     }
148 }
149
150 /*
151  * Initialize the OPENSSL_CTX global DRBGs on first use.
152  * Returns the allocated global data on success or NULL on failure.
153  */
154 static void *drbg_ossl_ctx_new(OPENSSL_CTX *libctx)
155 {
156     DRBG_GLOBAL *dgbl = OPENSSL_zalloc(sizeof(*dgbl));
157
158     if (dgbl == NULL)
159         return NULL;
160
161 #ifndef FIPS_MODE
162     /*
163      * We need to ensure that base libcrypto thread handling has been
164      * initialised.
165      */
166      OPENSSL_init_crypto(0, NULL);
167 #endif
168
169     if (!CRYPTO_THREAD_init_local(&dgbl->private_drbg, NULL))
170         goto err1;
171
172     if (!CRYPTO_THREAD_init_local(&dgbl->public_drbg, NULL))
173         goto err2;
174
175     dgbl->master_drbg = drbg_setup(libctx, NULL, RAND_DRBG_TYPE_MASTER);
176     if (dgbl->master_drbg == NULL)
177         goto err3;
178
179     return dgbl;
180
181  err3:
182     CRYPTO_THREAD_cleanup_local(&dgbl->public_drbg);
183  err2:
184     CRYPTO_THREAD_cleanup_local(&dgbl->private_drbg);
185  err1:
186     OPENSSL_free(dgbl);
187     return NULL;
188 }
189
190 static void drbg_ossl_ctx_free(void *vdgbl)
191 {
192     DRBG_GLOBAL *dgbl = vdgbl;
193
194     RAND_DRBG_free(dgbl->master_drbg);
195     CRYPTO_THREAD_cleanup_local(&dgbl->private_drbg);
196     CRYPTO_THREAD_cleanup_local(&dgbl->public_drbg);
197
198     OPENSSL_free(dgbl);
199 }
200
201 static const OPENSSL_CTX_METHOD drbg_ossl_ctx_method = {
202     drbg_ossl_ctx_new,
203     drbg_ossl_ctx_free,
204 };
205
206 /*
207  * drbg_ossl_ctx_new() calls drgb_setup() which calls rand_drbg_get_nonce()
208  * which needs to get the rand_nonce_lock out of the OPENSSL_CTX...but since
209  * drbg_ossl_ctx_new() hasn't finished running yet we need the rand_nonce_lock
210  * to be in a different global data object. Otherwise we will go into an
211  * infinite recursion loop.
212  */
213 static void *drbg_nonce_ossl_ctx_new(OPENSSL_CTX *libctx)
214 {
215     DRBG_NONCE_GLOBAL *dngbl = OPENSSL_zalloc(sizeof(*dngbl));
216
217     if (dngbl == NULL)
218         return NULL;
219
220     dngbl->rand_nonce_lock = CRYPTO_THREAD_lock_new();
221     if (dngbl->rand_nonce_lock == NULL) {
222         OPENSSL_free(dngbl);
223         return NULL;
224     }
225
226     return dngbl;
227 }
228
229 static void drbg_nonce_ossl_ctx_free(void *vdngbl)
230 {
231     DRBG_NONCE_GLOBAL *dngbl = vdngbl;
232
233     CRYPTO_THREAD_lock_free(dngbl->rand_nonce_lock);
234
235     OPENSSL_free(dngbl);
236 }
237
238 static const OPENSSL_CTX_METHOD drbg_nonce_ossl_ctx_method = {
239     drbg_nonce_ossl_ctx_new,
240     drbg_nonce_ossl_ctx_free,
241 };
242
243 static DRBG_GLOBAL *drbg_get_global(OPENSSL_CTX *libctx)
244 {
245     return openssl_ctx_get_data(libctx, OPENSSL_CTX_DRBG_INDEX,
246                                 &drbg_ossl_ctx_method);
247 }
248
249 /* Implements the get_nonce() callback (see RAND_DRBG_set_callbacks()) */
250 size_t rand_drbg_get_nonce(RAND_DRBG *drbg,
251                            unsigned char **pout,
252                            int entropy, size_t min_len, size_t max_len)
253 {
254     size_t ret = 0;
255     RAND_POOL *pool;
256     DRBG_NONCE_GLOBAL *dngbl
257         = openssl_ctx_get_data(drbg->libctx, OPENSSL_CTX_DRBG_NONCE_INDEX,
258                                &drbg_nonce_ossl_ctx_method);
259     struct {
260         void *instance;
261         int count;
262     } data;
263
264     if (dngbl == NULL)
265         return 0;
266
267     memset(&data, 0, sizeof(data));
268     pool = rand_pool_new(0, min_len, max_len);
269     if (pool == NULL)
270         return 0;
271
272     if (rand_pool_add_nonce_data(pool) == 0)
273         goto err;
274
275     data.instance = drbg;
276     CRYPTO_atomic_add(&dngbl->rand_nonce_count, 1, &data.count,
277                       dngbl->rand_nonce_lock);
278
279     if (rand_pool_add(pool, (unsigned char *)&data, sizeof(data), 0) == 0)
280         goto err;
281
282     ret   = rand_pool_length(pool);
283     *pout = rand_pool_detach(pool);
284
285  err:
286     rand_pool_free(pool);
287
288     return ret;
289 }
290
291 /*
292  * Implements the cleanup_nonce() callback (see RAND_DRBG_set_callbacks())
293  *
294  */
295 void rand_drbg_cleanup_nonce(RAND_DRBG *drbg,
296                              unsigned char *out, size_t outlen)
297 {
298     OPENSSL_secure_clear_free(out, outlen);
299 }
300
301 /*
302  * Set/initialize |drbg| to be of type |type|, with optional |flags|.
303  *
304  * If |type| and |flags| are zero, use the defaults
305  *
306  * Returns 1 on success, 0 on failure.
307  */
308 int RAND_DRBG_set(RAND_DRBG *drbg, int type, unsigned int flags)
309 {
310     int ret = 1;
311
312     if (type == 0 && flags == 0) {
313         type = rand_drbg_type[RAND_DRBG_TYPE_MASTER];
314         flags = rand_drbg_flags[RAND_DRBG_TYPE_MASTER];
315     }
316
317     /* If set is called multiple times - clear the old one */
318     if (drbg->type != 0 && (type != drbg->type || flags != drbg->flags)) {
319         drbg->meth->uninstantiate(drbg);
320         rand_pool_free(drbg->adin_pool);
321         drbg->adin_pool = NULL;
322     }
323
324     drbg->state = DRBG_UNINITIALISED;
325     drbg->flags = flags;
326     drbg->type = type;
327
328     if (type == 0) {
329         /* Uninitialized; that's okay. */
330         drbg->meth = NULL;
331         return 1;
332     } else if (is_ctr(type)) {
333         ret = drbg_ctr_init(drbg);
334     } else if (is_digest(type)) {
335         if (flags & RAND_DRBG_FLAG_HMAC)
336             ret = drbg_hmac_init(drbg);
337         else
338             ret = drbg_hash_init(drbg);
339     } else {
340         drbg->type = 0;
341         drbg->flags = 0;
342         drbg->meth = NULL;
343         RANDerr(RAND_F_RAND_DRBG_SET, RAND_R_UNSUPPORTED_DRBG_TYPE);
344         return 0;
345     }
346
347     if (ret == 0) {
348         drbg->state = DRBG_ERROR;
349         RANDerr(RAND_F_RAND_DRBG_SET, RAND_R_ERROR_INITIALISING_DRBG);
350     }
351     return ret;
352 }
353
354 /*
355  * Set/initialize default |type| and |flag| for new drbg instances.
356  *
357  * Returns 1 on success, 0 on failure.
358  */
359 int RAND_DRBG_set_defaults(int type, unsigned int flags)
360 {
361     int all;
362     if (!(is_digest(type) || is_ctr(type))) {
363         RANDerr(RAND_F_RAND_DRBG_SET_DEFAULTS, RAND_R_UNSUPPORTED_DRBG_TYPE);
364         return 0;
365     }
366
367     if ((flags & ~rand_drbg_used_flags) != 0) {
368         RANDerr(RAND_F_RAND_DRBG_SET_DEFAULTS, RAND_R_UNSUPPORTED_DRBG_FLAGS);
369         return 0;
370     }
371
372     all = ((flags & RAND_DRBG_TYPE_FLAGS) == 0);
373     if (all || (flags & RAND_DRBG_FLAG_MASTER) != 0) {
374         rand_drbg_type[RAND_DRBG_TYPE_MASTER] = type;
375         rand_drbg_flags[RAND_DRBG_TYPE_MASTER] = flags | RAND_DRBG_FLAG_MASTER;
376     }
377     if (all || (flags & RAND_DRBG_FLAG_PUBLIC) != 0) {
378         rand_drbg_type[RAND_DRBG_TYPE_PUBLIC]  = type;
379         rand_drbg_flags[RAND_DRBG_TYPE_PUBLIC] = flags | RAND_DRBG_FLAG_PUBLIC;
380     }
381     if (all || (flags & RAND_DRBG_FLAG_PRIVATE) != 0) {
382         rand_drbg_type[RAND_DRBG_TYPE_PRIVATE] = type;
383         rand_drbg_flags[RAND_DRBG_TYPE_PRIVATE] = flags | RAND_DRBG_FLAG_PRIVATE;
384     }
385     return 1;
386 }
387
388
389 /*
390  * Allocate memory and initialize a new DRBG. The DRBG is allocated on
391  * the secure heap if |secure| is nonzero and the secure heap is enabled.
392  * The |parent|, if not NULL, will be used as random source for reseeding.
393  *
394  * Returns a pointer to the new DRBG instance on success, NULL on failure.
395  */
396 static RAND_DRBG *rand_drbg_new(OPENSSL_CTX *ctx,
397                                 int secure,
398                                 int type,
399                                 unsigned int flags,
400                                 RAND_DRBG *parent)
401 {
402     RAND_DRBG *drbg = secure ? OPENSSL_secure_zalloc(sizeof(*drbg))
403                              : OPENSSL_zalloc(sizeof(*drbg));
404
405     if (drbg == NULL) {
406         RANDerr(RAND_F_RAND_DRBG_NEW, ERR_R_MALLOC_FAILURE);
407         return NULL;
408     }
409
410     drbg->libctx = ctx;
411     drbg->secure = secure && CRYPTO_secure_allocated(drbg);
412     drbg->fork_count = rand_fork_count;
413     drbg->parent = parent;
414
415     if (parent == NULL) {
416 #ifdef FIPS_MODE
417         drbg->get_entropy = rand_crngt_get_entropy;
418         drbg->cleanup_entropy = rand_crngt_cleanup_entropy;
419 #else
420         drbg->get_entropy = rand_drbg_get_entropy;
421         drbg->cleanup_entropy = rand_drbg_cleanup_entropy;
422 #endif
423 #ifndef RAND_DRBG_GET_RANDOM_NONCE
424         drbg->get_nonce = rand_drbg_get_nonce;
425         drbg->cleanup_nonce = rand_drbg_cleanup_nonce;
426 #endif
427
428         drbg->reseed_interval = master_reseed_interval;
429         drbg->reseed_time_interval = master_reseed_time_interval;
430     } else {
431         drbg->get_entropy = rand_drbg_get_entropy;
432         drbg->cleanup_entropy = rand_drbg_cleanup_entropy;
433         /*
434          * Do not provide nonce callbacks, the child DRBGs will
435          * obtain their nonce using random bits from the parent.
436          */
437
438         drbg->reseed_interval = slave_reseed_interval;
439         drbg->reseed_time_interval = slave_reseed_time_interval;
440     }
441
442     if (RAND_DRBG_set(drbg, type, flags) == 0)
443         goto err;
444
445     if (parent != NULL) {
446         rand_drbg_lock(parent);
447         if (drbg->strength > parent->strength) {
448             /*
449              * We currently don't support the algorithm from NIST SP 800-90C
450              * 10.1.2 to use a weaker DRBG as source
451              */
452             rand_drbg_unlock(parent);
453             RANDerr(RAND_F_RAND_DRBG_NEW, RAND_R_PARENT_STRENGTH_TOO_WEAK);
454             goto err;
455         }
456         rand_drbg_unlock(parent);
457     }
458
459     return drbg;
460
461  err:
462     RAND_DRBG_free(drbg);
463
464     return NULL;
465 }
466
467 RAND_DRBG *RAND_DRBG_new_ex(OPENSSL_CTX *ctx, int type, unsigned int flags,
468                             RAND_DRBG *parent)
469 {
470     return rand_drbg_new(ctx, 0, type, flags, parent);
471 }
472
473 RAND_DRBG *RAND_DRBG_new(int type, unsigned int flags, RAND_DRBG *parent)
474 {
475     return RAND_DRBG_new_ex(NULL, type, flags, parent);
476 }
477
478 RAND_DRBG *RAND_DRBG_secure_new_ex(OPENSSL_CTX *ctx, int type,
479                                    unsigned int flags, RAND_DRBG *parent)
480 {
481     return rand_drbg_new(ctx, 1, type, flags, parent);
482 }
483
484 RAND_DRBG *RAND_DRBG_secure_new(int type, unsigned int flags, RAND_DRBG *parent)
485 {
486     return RAND_DRBG_secure_new_ex(NULL, type, flags, parent);
487 }
488 /*
489  * Uninstantiate |drbg| and free all memory.
490  */
491 void RAND_DRBG_free(RAND_DRBG *drbg)
492 {
493     if (drbg == NULL)
494         return;
495
496     if (drbg->meth != NULL)
497         drbg->meth->uninstantiate(drbg);
498     rand_pool_free(drbg->adin_pool);
499     CRYPTO_THREAD_lock_free(drbg->lock);
500     CRYPTO_free_ex_data(CRYPTO_EX_INDEX_DRBG, drbg, &drbg->ex_data);
501
502     if (drbg->secure)
503         OPENSSL_secure_clear_free(drbg, sizeof(*drbg));
504     else
505         OPENSSL_clear_free(drbg, sizeof(*drbg));
506 }
507
508 /*
509  * Instantiate |drbg|, after it has been initialized.  Use |pers| and
510  * |perslen| as prediction-resistance input.
511  *
512  * Requires that drbg->lock is already locked for write, if non-null.
513  *
514  * Returns 1 on success, 0 on failure.
515  */
516 int RAND_DRBG_instantiate(RAND_DRBG *drbg,
517                           const unsigned char *pers, size_t perslen)
518 {
519     unsigned char *nonce = NULL, *entropy = NULL;
520     size_t noncelen = 0, entropylen = 0;
521     size_t min_entropy = drbg->strength;
522     size_t min_entropylen = drbg->min_entropylen;
523     size_t max_entropylen = drbg->max_entropylen;
524
525     if (perslen > drbg->max_perslen) {
526         RANDerr(RAND_F_RAND_DRBG_INSTANTIATE,
527                 RAND_R_PERSONALISATION_STRING_TOO_LONG);
528         goto end;
529     }
530
531     if (drbg->meth == NULL) {
532         RANDerr(RAND_F_RAND_DRBG_INSTANTIATE,
533                 RAND_R_NO_DRBG_IMPLEMENTATION_SELECTED);
534         goto end;
535     }
536
537     if (drbg->state != DRBG_UNINITIALISED) {
538         RANDerr(RAND_F_RAND_DRBG_INSTANTIATE,
539                 drbg->state == DRBG_ERROR ? RAND_R_IN_ERROR_STATE
540                                           : RAND_R_ALREADY_INSTANTIATED);
541         goto end;
542     }
543
544     drbg->state = DRBG_ERROR;
545
546     /*
547      * NIST SP800-90Ar1 section 9.1 says you can combine getting the entropy
548      * and nonce in 1 call by increasing the entropy with 50% and increasing
549      * the minimum length to accomadate the length of the nonce.
550      * We do this in case a nonce is require and get_nonce is NULL.
551      */
552     if (drbg->min_noncelen > 0 && drbg->get_nonce == NULL) {
553         min_entropy += drbg->strength / 2;
554         min_entropylen += drbg->min_noncelen;
555         max_entropylen += drbg->max_noncelen;
556     }
557
558     drbg->reseed_next_counter = tsan_load(&drbg->reseed_prop_counter);
559     if (drbg->reseed_next_counter) {
560         drbg->reseed_next_counter++;
561         if(!drbg->reseed_next_counter)
562             drbg->reseed_next_counter = 1;
563     }
564
565     if (drbg->get_entropy != NULL)
566         entropylen = drbg->get_entropy(drbg, &entropy, min_entropy,
567                                        min_entropylen, max_entropylen, 0);
568     if (entropylen < min_entropylen
569             || entropylen > max_entropylen) {
570         RANDerr(RAND_F_RAND_DRBG_INSTANTIATE, RAND_R_ERROR_RETRIEVING_ENTROPY);
571         goto end;
572     }
573
574     if (drbg->min_noncelen > 0 && drbg->get_nonce != NULL) {
575         noncelen = drbg->get_nonce(drbg, &nonce, drbg->strength / 2,
576                                    drbg->min_noncelen, drbg->max_noncelen);
577         if (noncelen < drbg->min_noncelen || noncelen > drbg->max_noncelen) {
578             RANDerr(RAND_F_RAND_DRBG_INSTANTIATE, RAND_R_ERROR_RETRIEVING_NONCE);
579             goto end;
580         }
581     }
582
583     if (!drbg->meth->instantiate(drbg, entropy, entropylen,
584                          nonce, noncelen, pers, perslen)) {
585         RANDerr(RAND_F_RAND_DRBG_INSTANTIATE, RAND_R_ERROR_INSTANTIATING_DRBG);
586         goto end;
587     }
588
589     drbg->state = DRBG_READY;
590     drbg->reseed_gen_counter = 1;
591     drbg->reseed_time = time(NULL);
592     tsan_store(&drbg->reseed_prop_counter, drbg->reseed_next_counter);
593
594  end:
595     if (entropy != NULL && drbg->cleanup_entropy != NULL)
596         drbg->cleanup_entropy(drbg, entropy, entropylen);
597     if (nonce != NULL && drbg->cleanup_nonce != NULL)
598         drbg->cleanup_nonce(drbg, nonce, noncelen);
599     if (drbg->state == DRBG_READY)
600         return 1;
601     return 0;
602 }
603
604 /*
605  * Uninstantiate |drbg|. Must be instantiated before it can be used.
606  *
607  * Requires that drbg->lock is already locked for write, if non-null.
608  *
609  * Returns 1 on success, 0 on failure.
610  */
611 int RAND_DRBG_uninstantiate(RAND_DRBG *drbg)
612 {
613     int index = -1, type, flags;
614     if (drbg->meth == NULL) {
615         drbg->state = DRBG_ERROR;
616         RANDerr(RAND_F_RAND_DRBG_UNINSTANTIATE,
617                 RAND_R_NO_DRBG_IMPLEMENTATION_SELECTED);
618         return 0;
619     }
620
621     /* Clear the entire drbg->ctr struct, then reset some important
622      * members of the drbg->ctr struct (e.g. keysize, df_ks) to their
623      * initial values.
624      */
625     drbg->meth->uninstantiate(drbg);
626
627     /* The reset uses the default values for type and flags */
628     if (drbg->flags & RAND_DRBG_FLAG_MASTER)
629         index = RAND_DRBG_TYPE_MASTER;
630     else if (drbg->flags & RAND_DRBG_FLAG_PRIVATE)
631         index = RAND_DRBG_TYPE_PRIVATE;
632     else if (drbg->flags & RAND_DRBG_FLAG_PUBLIC)
633         index = RAND_DRBG_TYPE_PUBLIC;
634
635     if (index != -1) {
636         flags = rand_drbg_flags[index];
637         type = rand_drbg_type[index];
638     } else {
639         flags = drbg->flags;
640         type = drbg->type;
641     }
642     return RAND_DRBG_set(drbg, type, flags);
643 }
644
645 /*
646  * Reseed |drbg|, mixing in the specified data
647  *
648  * Requires that drbg->lock is already locked for write, if non-null.
649  *
650  * Returns 1 on success, 0 on failure.
651  */
652 int RAND_DRBG_reseed(RAND_DRBG *drbg,
653                      const unsigned char *adin, size_t adinlen,
654                      int prediction_resistance)
655 {
656     unsigned char *entropy = NULL;
657     size_t entropylen = 0;
658
659     if (drbg->state == DRBG_ERROR) {
660         RANDerr(RAND_F_RAND_DRBG_RESEED, RAND_R_IN_ERROR_STATE);
661         return 0;
662     }
663     if (drbg->state == DRBG_UNINITIALISED) {
664         RANDerr(RAND_F_RAND_DRBG_RESEED, RAND_R_NOT_INSTANTIATED);
665         return 0;
666     }
667
668     if (adin == NULL) {
669         adinlen = 0;
670     } else if (adinlen > drbg->max_adinlen) {
671         RANDerr(RAND_F_RAND_DRBG_RESEED, RAND_R_ADDITIONAL_INPUT_TOO_LONG);
672         return 0;
673     }
674
675     drbg->state = DRBG_ERROR;
676
677     drbg->reseed_next_counter = tsan_load(&drbg->reseed_prop_counter);
678     if (drbg->reseed_next_counter) {
679         drbg->reseed_next_counter++;
680         if(!drbg->reseed_next_counter)
681             drbg->reseed_next_counter = 1;
682     }
683
684     if (drbg->get_entropy != NULL)
685         entropylen = drbg->get_entropy(drbg, &entropy, drbg->strength,
686                                        drbg->min_entropylen,
687                                        drbg->max_entropylen,
688                                        prediction_resistance);
689     if (entropylen < drbg->min_entropylen
690             || entropylen > drbg->max_entropylen) {
691         RANDerr(RAND_F_RAND_DRBG_RESEED, RAND_R_ERROR_RETRIEVING_ENTROPY);
692         goto end;
693     }
694
695     if (!drbg->meth->reseed(drbg, entropy, entropylen, adin, adinlen))
696         goto end;
697
698     drbg->state = DRBG_READY;
699     drbg->reseed_gen_counter = 1;
700     drbg->reseed_time = time(NULL);
701     tsan_store(&drbg->reseed_prop_counter, drbg->reseed_next_counter);
702
703  end:
704     if (entropy != NULL && drbg->cleanup_entropy != NULL)
705         drbg->cleanup_entropy(drbg, entropy, entropylen);
706     if (drbg->state == DRBG_READY)
707         return 1;
708     return 0;
709 }
710
711 /*
712  * Restart |drbg|, using the specified entropy or additional input
713  *
714  * Tries its best to get the drbg instantiated by all means,
715  * regardless of its current state.
716  *
717  * Optionally, a |buffer| of |len| random bytes can be passed,
718  * which is assumed to contain at least |entropy| bits of entropy.
719  *
720  * If |entropy| > 0, the buffer content is used as entropy input.
721  *
722  * If |entropy| == 0, the buffer content is used as additional input
723  *
724  * Returns 1 on success, 0 on failure.
725  *
726  * This function is used internally only.
727  */
728 int rand_drbg_restart(RAND_DRBG *drbg,
729                       const unsigned char *buffer, size_t len, size_t entropy)
730 {
731     int reseeded = 0;
732     const unsigned char *adin = NULL;
733     size_t adinlen = 0;
734
735     if (drbg->seed_pool != NULL) {
736         RANDerr(RAND_F_RAND_DRBG_RESTART, ERR_R_INTERNAL_ERROR);
737         drbg->state = DRBG_ERROR;
738         rand_pool_free(drbg->seed_pool);
739         drbg->seed_pool = NULL;
740         return 0;
741     }
742
743     if (buffer != NULL) {
744         if (entropy > 0) {
745             if (drbg->max_entropylen < len) {
746                 RANDerr(RAND_F_RAND_DRBG_RESTART,
747                     RAND_R_ENTROPY_INPUT_TOO_LONG);
748                 drbg->state = DRBG_ERROR;
749                 return 0;
750             }
751
752             if (entropy > 8 * len) {
753                 RANDerr(RAND_F_RAND_DRBG_RESTART, RAND_R_ENTROPY_OUT_OF_RANGE);
754                 drbg->state = DRBG_ERROR;
755                 return 0;
756             }
757
758             /* will be picked up by the rand_drbg_get_entropy() callback */
759             drbg->seed_pool = rand_pool_attach(buffer, len, entropy);
760             if (drbg->seed_pool == NULL)
761                 return 0;
762         } else {
763             if (drbg->max_adinlen < len) {
764                 RANDerr(RAND_F_RAND_DRBG_RESTART,
765                         RAND_R_ADDITIONAL_INPUT_TOO_LONG);
766                 drbg->state = DRBG_ERROR;
767                 return 0;
768             }
769             adin = buffer;
770             adinlen = len;
771         }
772     }
773
774     /* repair error state */
775     if (drbg->state == DRBG_ERROR)
776         RAND_DRBG_uninstantiate(drbg);
777
778     /* repair uninitialized state */
779     if (drbg->state == DRBG_UNINITIALISED) {
780         /* reinstantiate drbg */
781         RAND_DRBG_instantiate(drbg,
782                               (const unsigned char *) ossl_pers_string,
783                               sizeof(ossl_pers_string) - 1);
784         /* already reseeded. prevent second reseeding below */
785         reseeded = (drbg->state == DRBG_READY);
786     }
787
788     /* refresh current state if entropy or additional input has been provided */
789     if (drbg->state == DRBG_READY) {
790         if (adin != NULL) {
791             /*
792              * mix in additional input without reseeding
793              *
794              * Similar to RAND_DRBG_reseed(), but the provided additional
795              * data |adin| is mixed into the current state without pulling
796              * entropy from the trusted entropy source using get_entropy().
797              * This is not a reseeding in the strict sense of NIST SP 800-90A.
798              */
799             drbg->meth->reseed(drbg, adin, adinlen, NULL, 0);
800         } else if (reseeded == 0) {
801             /* do a full reseeding if it has not been done yet above */
802             RAND_DRBG_reseed(drbg, NULL, 0, 0);
803         }
804     }
805
806     rand_pool_free(drbg->seed_pool);
807     drbg->seed_pool = NULL;
808
809     return drbg->state == DRBG_READY;
810 }
811
812 /*
813  * Generate |outlen| bytes into the buffer at |out|.  Reseed if we need
814  * to or if |prediction_resistance| is set.  Additional input can be
815  * sent in |adin| and |adinlen|.
816  *
817  * Requires that drbg->lock is already locked for write, if non-null.
818  *
819  * Returns 1 on success, 0 on failure.
820  *
821  */
822 int RAND_DRBG_generate(RAND_DRBG *drbg, unsigned char *out, size_t outlen,
823                        int prediction_resistance,
824                        const unsigned char *adin, size_t adinlen)
825 {
826     int reseed_required = 0;
827
828     if (drbg->state != DRBG_READY) {
829         /* try to recover from previous errors */
830         rand_drbg_restart(drbg, NULL, 0, 0);
831
832         if (drbg->state == DRBG_ERROR) {
833             RANDerr(RAND_F_RAND_DRBG_GENERATE, RAND_R_IN_ERROR_STATE);
834             return 0;
835         }
836         if (drbg->state == DRBG_UNINITIALISED) {
837             RANDerr(RAND_F_RAND_DRBG_GENERATE, RAND_R_NOT_INSTANTIATED);
838             return 0;
839         }
840     }
841
842     if (outlen > drbg->max_request) {
843         RANDerr(RAND_F_RAND_DRBG_GENERATE, RAND_R_REQUEST_TOO_LARGE_FOR_DRBG);
844         return 0;
845     }
846     if (adinlen > drbg->max_adinlen) {
847         RANDerr(RAND_F_RAND_DRBG_GENERATE, RAND_R_ADDITIONAL_INPUT_TOO_LONG);
848         return 0;
849     }
850
851     if (drbg->fork_count != rand_fork_count) {
852         drbg->fork_count = rand_fork_count;
853         reseed_required = 1;
854     }
855
856     if (drbg->reseed_interval > 0) {
857         if (drbg->reseed_gen_counter > drbg->reseed_interval)
858             reseed_required = 1;
859     }
860     if (drbg->reseed_time_interval > 0) {
861         time_t now = time(NULL);
862         if (now < drbg->reseed_time
863             || now - drbg->reseed_time >= drbg->reseed_time_interval)
864             reseed_required = 1;
865     }
866     if (drbg->parent != NULL) {
867         unsigned int reseed_counter = tsan_load(&drbg->reseed_prop_counter);
868         if (reseed_counter > 0
869                 && tsan_load(&drbg->parent->reseed_prop_counter)
870                    != reseed_counter)
871             reseed_required = 1;
872     }
873
874     if (reseed_required || prediction_resistance) {
875         if (!RAND_DRBG_reseed(drbg, adin, adinlen, prediction_resistance)) {
876             RANDerr(RAND_F_RAND_DRBG_GENERATE, RAND_R_RESEED_ERROR);
877             return 0;
878         }
879         adin = NULL;
880         adinlen = 0;
881     }
882
883     if (!drbg->meth->generate(drbg, out, outlen, adin, adinlen)) {
884         drbg->state = DRBG_ERROR;
885         RANDerr(RAND_F_RAND_DRBG_GENERATE, RAND_R_GENERATE_ERROR);
886         return 0;
887     }
888
889     drbg->reseed_gen_counter++;
890
891     return 1;
892 }
893
894 /*
895  * Generates |outlen| random bytes and stores them in |out|. It will
896  * using the given |drbg| to generate the bytes.
897  *
898  * Requires that drbg->lock is already locked for write, if non-null.
899  *
900  * Returns 1 on success 0 on failure.
901  */
902 int RAND_DRBG_bytes(RAND_DRBG *drbg, unsigned char *out, size_t outlen)
903 {
904     unsigned char *additional = NULL;
905     size_t additional_len;
906     size_t chunk;
907     size_t ret = 0;
908
909     if (drbg->adin_pool == NULL) {
910         if (drbg->type == 0)
911             goto err;
912         drbg->adin_pool = rand_pool_new(0, 0, drbg->max_adinlen);
913         if (drbg->adin_pool == NULL)
914             goto err;
915     }
916
917     additional_len = rand_drbg_get_additional_data(drbg->adin_pool,
918                                                    &additional);
919
920     for ( ; outlen > 0; outlen -= chunk, out += chunk) {
921         chunk = outlen;
922         if (chunk > drbg->max_request)
923             chunk = drbg->max_request;
924         ret = RAND_DRBG_generate(drbg, out, chunk, 0, additional, additional_len);
925         if (!ret)
926             goto err;
927     }
928     ret = 1;
929
930  err:
931     if (additional != NULL)
932         rand_drbg_cleanup_additional_data(drbg->adin_pool, additional);
933
934     return ret;
935 }
936
937 /*
938  * Set the RAND_DRBG callbacks for obtaining entropy and nonce.
939  *
940  * Setting the callbacks is allowed only if the drbg has not been
941  * initialized yet. Otherwise, the operation will fail.
942  *
943  * Returns 1 on success, 0 on failure.
944  */
945 int RAND_DRBG_set_callbacks(RAND_DRBG *drbg,
946                             RAND_DRBG_get_entropy_fn get_entropy,
947                             RAND_DRBG_cleanup_entropy_fn cleanup_entropy,
948                             RAND_DRBG_get_nonce_fn get_nonce,
949                             RAND_DRBG_cleanup_nonce_fn cleanup_nonce)
950 {
951     if (drbg->state != DRBG_UNINITIALISED
952             || drbg->parent != NULL)
953         return 0;
954     drbg->get_entropy = get_entropy;
955     drbg->cleanup_entropy = cleanup_entropy;
956     drbg->get_nonce = get_nonce;
957     drbg->cleanup_nonce = cleanup_nonce;
958     return 1;
959 }
960
961 /*
962  * Set the reseed interval.
963  *
964  * The drbg will reseed automatically whenever the number of generate
965  * requests exceeds the given reseed interval. If the reseed interval
966  * is 0, then this feature is disabled.
967  *
968  * Returns 1 on success, 0 on failure.
969  */
970 int RAND_DRBG_set_reseed_interval(RAND_DRBG *drbg, unsigned int interval)
971 {
972     if (interval > MAX_RESEED_INTERVAL)
973         return 0;
974     drbg->reseed_interval = interval;
975     return 1;
976 }
977
978 /*
979  * Set the reseed time interval.
980  *
981  * The drbg will reseed automatically whenever the time elapsed since
982  * the last reseeding exceeds the given reseed time interval. For safety,
983  * a reseeding will also occur if the clock has been reset to a smaller
984  * value.
985  *
986  * Returns 1 on success, 0 on failure.
987  */
988 int RAND_DRBG_set_reseed_time_interval(RAND_DRBG *drbg, time_t interval)
989 {
990     if (interval > MAX_RESEED_TIME_INTERVAL)
991         return 0;
992     drbg->reseed_time_interval = interval;
993     return 1;
994 }
995
996 /*
997  * Set the default values for reseed (time) intervals of new DRBG instances
998  *
999  * The default values can be set independently for master DRBG instances
1000  * (without a parent) and slave DRBG instances (with parent).
1001  *
1002  * Returns 1 on success, 0 on failure.
1003  */
1004
1005 int RAND_DRBG_set_reseed_defaults(
1006                                   unsigned int _master_reseed_interval,
1007                                   unsigned int _slave_reseed_interval,
1008                                   time_t _master_reseed_time_interval,
1009                                   time_t _slave_reseed_time_interval
1010                                   )
1011 {
1012     if (_master_reseed_interval > MAX_RESEED_INTERVAL
1013         || _slave_reseed_interval > MAX_RESEED_INTERVAL)
1014         return 0;
1015
1016     if (_master_reseed_time_interval > MAX_RESEED_TIME_INTERVAL
1017         || _slave_reseed_time_interval > MAX_RESEED_TIME_INTERVAL)
1018         return 0;
1019
1020     master_reseed_interval = _master_reseed_interval;
1021     slave_reseed_interval = _slave_reseed_interval;
1022
1023     master_reseed_time_interval = _master_reseed_time_interval;
1024     slave_reseed_time_interval = _slave_reseed_time_interval;
1025
1026     return 1;
1027 }
1028
1029 /*
1030  * Locks the given drbg. Locking a drbg which does not have locking
1031  * enabled is considered a successful no-op.
1032  *
1033  * Returns 1 on success, 0 on failure.
1034  */
1035 int rand_drbg_lock(RAND_DRBG *drbg)
1036 {
1037     if (drbg->lock != NULL)
1038         return CRYPTO_THREAD_write_lock(drbg->lock);
1039
1040     return 1;
1041 }
1042
1043 /*
1044  * Unlocks the given drbg. Unlocking a drbg which does not have locking
1045  * enabled is considered a successful no-op.
1046  *
1047  * Returns 1 on success, 0 on failure.
1048  */
1049 int rand_drbg_unlock(RAND_DRBG *drbg)
1050 {
1051     if (drbg->lock != NULL)
1052         return CRYPTO_THREAD_unlock(drbg->lock);
1053
1054     return 1;
1055 }
1056
1057 /*
1058  * Enables locking for the given drbg
1059  *
1060  * Locking can only be enabled if the random generator
1061  * is in the uninitialized state.
1062  *
1063  * Returns 1 on success, 0 on failure.
1064  */
1065 int rand_drbg_enable_locking(RAND_DRBG *drbg)
1066 {
1067     if (drbg->state != DRBG_UNINITIALISED) {
1068         RANDerr(RAND_F_RAND_DRBG_ENABLE_LOCKING,
1069                 RAND_R_DRBG_ALREADY_INITIALIZED);
1070         return 0;
1071     }
1072
1073     if (drbg->lock == NULL) {
1074         if (drbg->parent != NULL && drbg->parent->lock == NULL) {
1075             RANDerr(RAND_F_RAND_DRBG_ENABLE_LOCKING,
1076                     RAND_R_PARENT_LOCKING_NOT_ENABLED);
1077             return 0;
1078         }
1079
1080         drbg->lock = CRYPTO_THREAD_lock_new();
1081         if (drbg->lock == NULL) {
1082             RANDerr(RAND_F_RAND_DRBG_ENABLE_LOCKING,
1083                     RAND_R_FAILED_TO_CREATE_LOCK);
1084             return 0;
1085         }
1086     }
1087
1088     return 1;
1089 }
1090
1091 /*
1092  * Get and set the EXDATA
1093  */
1094 int RAND_DRBG_set_ex_data(RAND_DRBG *drbg, int idx, void *arg)
1095 {
1096     return CRYPTO_set_ex_data(&drbg->ex_data, idx, arg);
1097 }
1098
1099 void *RAND_DRBG_get_ex_data(const RAND_DRBG *drbg, int idx)
1100 {
1101     return CRYPTO_get_ex_data(&drbg->ex_data, idx);
1102 }
1103
1104
1105 /*
1106  * The following functions provide a RAND_METHOD that works on the
1107  * global DRBG.  They lock.
1108  */
1109
1110 /*
1111  * Allocates a new global DRBG on the secure heap (if enabled) and
1112  * initializes it with default settings.
1113  *
1114  * Returns a pointer to the new DRBG instance on success, NULL on failure.
1115  */
1116 static RAND_DRBG *drbg_setup(OPENSSL_CTX *ctx, RAND_DRBG *parent, int drbg_type)
1117 {
1118     RAND_DRBG *drbg;
1119
1120     drbg = RAND_DRBG_secure_new_ex(ctx, rand_drbg_type[drbg_type],
1121                                    rand_drbg_flags[drbg_type], parent);
1122     if (drbg == NULL)
1123         return NULL;
1124
1125     /* Only the master DRBG needs to have a lock */
1126     if (parent == NULL && rand_drbg_enable_locking(drbg) == 0)
1127         goto err;
1128
1129     /* enable seed propagation */
1130     tsan_store(&drbg->reseed_prop_counter, 1);
1131
1132     /*
1133      * Ignore instantiation error to support just-in-time instantiation.
1134      *
1135      * The state of the drbg will be checked in RAND_DRBG_generate() and
1136      * an automatic recovery is attempted.
1137      */
1138     (void)RAND_DRBG_instantiate(drbg,
1139                                 (const unsigned char *) ossl_pers_string,
1140                                 sizeof(ossl_pers_string) - 1);
1141     return drbg;
1142
1143 err:
1144     RAND_DRBG_free(drbg);
1145     return NULL;
1146 }
1147
1148 static void drbg_delete_thread_state(void *arg)
1149 {
1150     OPENSSL_CTX *ctx = arg;
1151     DRBG_GLOBAL *dgbl = drbg_get_global(ctx);
1152     RAND_DRBG *drbg;
1153
1154     if (dgbl == NULL)
1155         return;
1156     drbg = CRYPTO_THREAD_get_local(&dgbl->public_drbg);
1157     CRYPTO_THREAD_set_local(&dgbl->public_drbg, NULL);
1158     RAND_DRBG_free(drbg);
1159
1160     drbg = CRYPTO_THREAD_get_local(&dgbl->private_drbg);
1161     CRYPTO_THREAD_set_local(&dgbl->private_drbg, NULL);
1162     RAND_DRBG_free(drbg);
1163 }
1164
1165 /* Implements the default OpenSSL RAND_bytes() method */
1166 static int drbg_bytes(unsigned char *out, int count)
1167 {
1168     int ret;
1169     RAND_DRBG *drbg = RAND_DRBG_get0_public();
1170
1171     if (drbg == NULL)
1172         return 0;
1173
1174     ret = RAND_DRBG_bytes(drbg, out, count);
1175
1176     return ret;
1177 }
1178
1179 /*
1180  * Calculates the minimum length of a full entropy buffer
1181  * which is necessary to seed (i.e. instantiate) the DRBG
1182  * successfully.
1183  */
1184 size_t rand_drbg_seedlen(RAND_DRBG *drbg)
1185 {
1186     /*
1187      * If no os entropy source is available then RAND_seed(buffer, bufsize)
1188      * is expected to succeed if and only if the buffer length satisfies
1189      * the following requirements, which follow from the calculations
1190      * in RAND_DRBG_instantiate().
1191      */
1192     size_t min_entropy = drbg->strength;
1193     size_t min_entropylen = drbg->min_entropylen;
1194
1195     /*
1196      * Extra entropy for the random nonce in the absence of a
1197      * get_nonce callback, see comment in RAND_DRBG_instantiate().
1198      */
1199     if (drbg->min_noncelen > 0 && drbg->get_nonce == NULL) {
1200         min_entropy += drbg->strength / 2;
1201         min_entropylen += drbg->min_noncelen;
1202     }
1203
1204     /*
1205      * Convert entropy requirement from bits to bytes
1206      * (dividing by 8 without rounding upwards, because
1207      * all entropy requirements are divisible by 8).
1208      */
1209     min_entropy >>= 3;
1210
1211     /* Return a value that satisfies both requirements */
1212     return min_entropy > min_entropylen ? min_entropy : min_entropylen;
1213 }
1214
1215 /* Implements the default OpenSSL RAND_add() method */
1216 static int drbg_add(const void *buf, int num, double randomness)
1217 {
1218     int ret = 0;
1219     RAND_DRBG *drbg = RAND_DRBG_get0_master();
1220     size_t buflen;
1221     size_t seedlen;
1222
1223     if (drbg == NULL)
1224         return 0;
1225
1226     if (num < 0 || randomness < 0.0)
1227         return 0;
1228
1229     rand_drbg_lock(drbg);
1230     seedlen = rand_drbg_seedlen(drbg);
1231
1232     buflen = (size_t)num;
1233
1234 #ifdef FIPS_MODE
1235     /*
1236      * NIST SP-800-90A mandates that entropy *shall not* be provided
1237      * by the consuming application. By setting the randomness to zero,
1238      * we ensure that the buffer contents will be added to the internal
1239      * state of the DRBG only as additional data.
1240      *
1241      * (NIST SP-800-90Ar1, Sections 9.1 and 9.2)
1242      */
1243     randomness = 0.0;
1244 #endif
1245     if (buflen < seedlen || randomness < (double) seedlen) {
1246 #if defined(OPENSSL_RAND_SEED_NONE)
1247         /*
1248          * If no os entropy source is available, a reseeding will fail
1249          * inevitably. So we use a trick to mix the buffer contents into
1250          * the DRBG state without forcing a reseeding: we generate a
1251          * dummy random byte, using the buffer content as additional data.
1252          * Note: This won't work with RAND_DRBG_FLAG_CTR_NO_DF.
1253          */
1254         unsigned char dummy[1];
1255
1256         ret = RAND_DRBG_generate(drbg, dummy, sizeof(dummy), 0, buf, buflen);
1257         rand_drbg_unlock(drbg);
1258         return ret;
1259 #else
1260         /*
1261          * If an os entropy source is available then we declare the buffer content
1262          * as additional data by setting randomness to zero and trigger a regular
1263          * reseeding.
1264          */
1265         randomness = 0.0;
1266 #endif
1267     }
1268
1269     if (randomness > (double)seedlen) {
1270         /*
1271          * The purpose of this check is to bound |randomness| by a
1272          * relatively small value in order to prevent an integer
1273          * overflow when multiplying by 8 in the rand_drbg_restart()
1274          * call below. Note that randomness is measured in bytes,
1275          * not bits, so this value corresponds to eight times the
1276          * security strength.
1277          */
1278         randomness = (double)seedlen;
1279     }
1280
1281     ret = rand_drbg_restart(drbg, buf, buflen, (size_t)(8 * randomness));
1282     rand_drbg_unlock(drbg);
1283
1284     return ret;
1285 }
1286
1287 /* Implements the default OpenSSL RAND_seed() method */
1288 static int drbg_seed(const void *buf, int num)
1289 {
1290     return drbg_add(buf, num, num);
1291 }
1292
1293 /* Implements the default OpenSSL RAND_status() method */
1294 static int drbg_status(void)
1295 {
1296     int ret;
1297     RAND_DRBG *drbg = RAND_DRBG_get0_master();
1298
1299     if (drbg == NULL)
1300         return 0;
1301
1302     rand_drbg_lock(drbg);
1303     ret = drbg->state == DRBG_READY ? 1 : 0;
1304     rand_drbg_unlock(drbg);
1305     return ret;
1306 }
1307
1308 /*
1309  * Get the master DRBG.
1310  * Returns pointer to the DRBG on success, NULL on failure.
1311  *
1312  */
1313 RAND_DRBG *OPENSSL_CTX_get0_master_drbg(OPENSSL_CTX *ctx)
1314 {
1315     DRBG_GLOBAL *dgbl = drbg_get_global(ctx);
1316
1317     if (dgbl == NULL)
1318         return NULL;
1319
1320     return dgbl->master_drbg;
1321 }
1322
1323 RAND_DRBG *RAND_DRBG_get0_master(void)
1324 {
1325     return OPENSSL_CTX_get0_master_drbg(NULL);
1326 }
1327
1328 /*
1329  * Get the public DRBG.
1330  * Returns pointer to the DRBG on success, NULL on failure.
1331  */
1332 RAND_DRBG *OPENSSL_CTX_get0_public_drbg(OPENSSL_CTX *ctx)
1333 {
1334     DRBG_GLOBAL *dgbl = drbg_get_global(ctx);
1335     RAND_DRBG *drbg;
1336
1337     if (dgbl == NULL)
1338         return NULL;
1339
1340     drbg = CRYPTO_THREAD_get_local(&dgbl->public_drbg);
1341     if (drbg == NULL) {
1342         if (!ossl_init_thread_start(NULL, drbg_delete_thread_state))
1343             return NULL;
1344         drbg = drbg_setup(ctx, dgbl->master_drbg, RAND_DRBG_TYPE_PUBLIC);
1345         CRYPTO_THREAD_set_local(&dgbl->public_drbg, drbg);
1346     }
1347     return drbg;
1348 }
1349
1350 RAND_DRBG *RAND_DRBG_get0_public(void)
1351 {
1352     return OPENSSL_CTX_get0_public_drbg(NULL);
1353 }
1354
1355 /*
1356  * Get the private DRBG.
1357  * Returns pointer to the DRBG on success, NULL on failure.
1358  */
1359 RAND_DRBG *OPENSSL_CTX_get0_private_drbg(OPENSSL_CTX *ctx)
1360 {
1361     DRBG_GLOBAL *dgbl = drbg_get_global(ctx);
1362     RAND_DRBG *drbg;
1363
1364     if (dgbl == NULL)
1365         return NULL;
1366
1367     drbg = CRYPTO_THREAD_get_local(&dgbl->private_drbg);
1368     if (drbg == NULL) {
1369         if (!ossl_init_thread_start(NULL, drbg_delete_thread_state))
1370             return NULL;
1371         drbg = drbg_setup(ctx, dgbl->master_drbg, RAND_DRBG_TYPE_PRIVATE);
1372         CRYPTO_THREAD_set_local(&dgbl->private_drbg, drbg);
1373     }
1374     return drbg;
1375 }
1376
1377 RAND_DRBG *RAND_DRBG_get0_private(void)
1378 {
1379     return OPENSSL_CTX_get0_private_drbg(NULL);
1380 }
1381
1382 RAND_METHOD rand_meth = {
1383     drbg_seed,
1384     drbg_bytes,
1385     NULL,
1386     drbg_add,
1387     drbg_bytes,
1388     drbg_status
1389 };
1390
1391 RAND_METHOD *RAND_OpenSSL(void)
1392 {
1393 #ifndef FIPS_MODE
1394     return &rand_meth;
1395 #else
1396     return NULL;
1397 #endif
1398 }