1/*
2 * Copyright 1995-2018 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 <stdio.h>
11#include <time.h>
12#include "internal/cryptlib.h"
13#include <openssl/opensslconf.h>
14#include "crypto/rand.h"
15#include <openssl/engine.h>
16#include "internal/thread_once.h"
17#include "rand_local.h"
18#include "e_os.h"
19
20#ifndef FIPS_MODE
21# ifndef OPENSSL_NO_ENGINE
22/* non-NULL if default_RAND_meth is ENGINE-provided */
23static ENGINE *funct_ref;
24static CRYPTO_RWLOCK *rand_engine_lock;
25# endif
26static CRYPTO_RWLOCK *rand_meth_lock;
27static const RAND_METHOD *default_RAND_meth;
28static CRYPTO_ONCE rand_init = CRYPTO_ONCE_STATIC_INIT;
29
30static int rand_inited = 0;
31#endif /* FIPS_MODE */
32
33#ifdef OPENSSL_RAND_SEED_RDTSC
34/*
35 * IMPORTANT NOTE: It is not currently possible to use this code
36 * because we are not sure about the amount of randomness it provides.
37 * Some SP900 tests have been run, but there is internal skepticism.
38 * So for now this code is not used.
39 */
40# error "RDTSC enabled? Should not be possible!"
41
42/*
43 * Acquire entropy from high-speed clock
44 *
45 * Since we get some randomness from the low-order bits of the
46 * high-speed clock, it can help.
47 *
48 * Returns the total entropy count, if it exceeds the requested
49 * entropy count. Otherwise, returns an entropy count of 0.
50 */
51size_t rand_acquire_entropy_from_tsc(RAND_POOL *pool)
52{
53 unsigned char c;
54 int i;
55
56 if ((OPENSSL_ia32cap_P[0] & (1 << 4)) != 0) {
57 for (i = 0; i < TSC_READ_COUNT; i++) {
58 c = (unsigned char)(OPENSSL_rdtsc() & 0xFF);
59 rand_pool_add(pool, &c, 1, 4);
60 }
61 }
62 return rand_pool_entropy_available(pool);
63}
64#endif
65
66#ifdef OPENSSL_RAND_SEED_RDCPU
67size_t OPENSSL_ia32_rdseed_bytes(unsigned char *buf, size_t len);
68size_t OPENSSL_ia32_rdrand_bytes(unsigned char *buf, size_t len);
69
70/*
71 * Acquire entropy using Intel-specific cpu instructions
72 *
73 * Uses the RDSEED instruction if available, otherwise uses
74 * RDRAND if available.
75 *
76 * For the differences between RDSEED and RDRAND, and why RDSEED
77 * is the preferred choice, see https://goo.gl/oK3KcN
78 *
79 * Returns the total entropy count, if it exceeds the requested
80 * entropy count. Otherwise, returns an entropy count of 0.
81 */
82size_t rand_acquire_entropy_from_cpu(RAND_POOL *pool)
83{
84 size_t bytes_needed;
85 unsigned char *buffer;
86
87 bytes_needed = rand_pool_bytes_needed(pool, 1 /*entropy_factor*/);
88 if (bytes_needed > 0) {
89 buffer = rand_pool_add_begin(pool, bytes_needed);
90
91 if (buffer != NULL) {
92 /* Whichever comes first, use RDSEED, RDRAND or nothing */
93 if ((OPENSSL_ia32cap_P[2] & (1 << 18)) != 0) {
94 if (OPENSSL_ia32_rdseed_bytes(buffer, bytes_needed)
95 == bytes_needed) {
96 rand_pool_add_end(pool, bytes_needed, 8 * bytes_needed);
97 }
98 } else if ((OPENSSL_ia32cap_P[1] & (1 << (62 - 32))) != 0) {
99 if (OPENSSL_ia32_rdrand_bytes(buffer, bytes_needed)
100 == bytes_needed) {
101 rand_pool_add_end(pool, bytes_needed, 8 * bytes_needed);
102 }
103 } else {
104 rand_pool_add_end(pool, 0, 0);
105 }
106 }
107 }
108
109 return rand_pool_entropy_available(pool);
110}
111#endif
112
113
114/*
115 * Implements the get_entropy() callback (see RAND_DRBG_set_callbacks())
116 *
117 * If the DRBG has a parent, then the required amount of entropy input
118 * is fetched using the parent's RAND_DRBG_generate().
119 *
120 * Otherwise, the entropy is polled from the system entropy sources
121 * using rand_pool_acquire_entropy().
122 *
123 * If a random pool has been added to the DRBG using RAND_add(), then
124 * its entropy will be used up first.
125 */
126size_t rand_drbg_get_entropy(RAND_DRBG *drbg,
127 unsigned char **pout,
128 int entropy, size_t min_len, size_t max_len,
129 int prediction_resistance)
130{
131 size_t ret = 0;
132 size_t entropy_available = 0;
133 RAND_POOL *pool;
134
135 if (drbg->parent != NULL && drbg->strength > drbg->parent->strength) {
136 /*
137 * We currently don't support the algorithm from NIST SP 800-90C
138 * 10.1.2 to use a weaker DRBG as source
139 */
140 RANDerr(RAND_F_RAND_DRBG_GET_ENTROPY, RAND_R_PARENT_STRENGTH_TOO_WEAK);
141 return 0;
142 }
143
144 if (drbg->seed_pool != NULL) {
145 pool = drbg->seed_pool;
146 pool->entropy_requested = entropy;
147 } else {
148 pool = rand_pool_new(entropy, drbg->secure, min_len, max_len);
149 if (pool == NULL)
150 return 0;
151 }
152
153 if (drbg->parent != NULL) {
154 size_t bytes_needed = rand_pool_bytes_needed(pool, 1 /*entropy_factor*/);
155 unsigned char *buffer = rand_pool_add_begin(pool, bytes_needed);
156
157 if (buffer != NULL) {
158 size_t bytes = 0;
159
160 /*
161 * Get random data from parent. Include our address as additional input,
162 * in order to provide some additional distinction between different
163 * DRBG child instances.
164 * Our lock is already held, but we need to lock our parent before
165 * generating bits from it. (Note: taking the lock will be a no-op
166 * if locking if drbg->parent->lock == NULL.)
167 */
168 rand_drbg_lock(drbg->parent);
169 if (RAND_DRBG_generate(drbg->parent,
170 buffer, bytes_needed,
171 prediction_resistance,
172 (unsigned char *)&drbg, sizeof(drbg)) != 0)
173 bytes = bytes_needed;
174 drbg->reseed_next_counter
175 = tsan_load(&drbg->parent->reseed_prop_counter);
176 rand_drbg_unlock(drbg->parent);
177
178 rand_pool_add_end(pool, bytes, 8 * bytes);
179 entropy_available = rand_pool_entropy_available(pool);
180 }
181
182 } else {
183 /* Get entropy by polling system entropy sources. */
184 entropy_available = rand_pool_acquire_entropy(pool);
185 }
186
187 if (entropy_available > 0) {
188 ret = rand_pool_length(pool);
189 *pout = rand_pool_detach(pool);
190 }
191
192 if (drbg->seed_pool == NULL)
193 rand_pool_free(pool);
194 return ret;
195}
196
197/*
198 * Implements the cleanup_entropy() callback (see RAND_DRBG_set_callbacks())
199 *
200 */
201void rand_drbg_cleanup_entropy(RAND_DRBG *drbg,
202 unsigned char *out, size_t outlen)
203{
204 if (drbg->seed_pool == NULL) {
205 if (drbg->secure)
206 OPENSSL_secure_clear_free(out, outlen);
207 else
208 OPENSSL_clear_free(out, outlen);
209 }
210}
211
212/*
213 * Generate additional data that can be used for the drbg. The data does
214 * not need to contain entropy, but it's useful if it contains at least
215 * some bits that are unpredictable.
216 *
217 * Returns 0 on failure.
218 *
219 * On success it allocates a buffer at |*pout| and returns the length of
220 * the data. The buffer should get freed using OPENSSL_secure_clear_free().
221 */
222size_t rand_drbg_get_additional_data(RAND_POOL *pool, unsigned char **pout)
223{
224 size_t ret = 0;
225
226 if (rand_pool_add_additional_data(pool) == 0)
227 goto err;
228
229 ret = rand_pool_length(pool);
230 *pout = rand_pool_detach(pool);
231
232 err:
233 return ret;
234}
235
236void rand_drbg_cleanup_additional_data(RAND_POOL *pool, unsigned char *out)
237{
238 rand_pool_reattach(pool, out);
239}
240
241#ifndef FIPS_MODE
242DEFINE_RUN_ONCE_STATIC(do_rand_init)
243{
244# ifndef OPENSSL_NO_ENGINE
245 rand_engine_lock = CRYPTO_THREAD_lock_new();
246 if (rand_engine_lock == NULL)
247 return 0;
248# endif
249
250 rand_meth_lock = CRYPTO_THREAD_lock_new();
251 if (rand_meth_lock == NULL)
252 goto err;
253
254 if (!rand_pool_init())
255 goto err;
256
257 rand_inited = 1;
258 return 1;
259
260 err:
261 CRYPTO_THREAD_lock_free(rand_meth_lock);
262 rand_meth_lock = NULL;
263# ifndef OPENSSL_NO_ENGINE
264 CRYPTO_THREAD_lock_free(rand_engine_lock);
265 rand_engine_lock = NULL;
266# endif
267 return 0;
268}
269
270void rand_cleanup_int(void)
271{
272 const RAND_METHOD *meth = default_RAND_meth;
273
274 if (!rand_inited)
275 return;
276
277 if (meth != NULL && meth->cleanup != NULL)
278 meth->cleanup();
279 RAND_set_rand_method(NULL);
280 rand_pool_cleanup();
281# ifndef OPENSSL_NO_ENGINE
282 CRYPTO_THREAD_lock_free(rand_engine_lock);
283 rand_engine_lock = NULL;
284# endif
285 CRYPTO_THREAD_lock_free(rand_meth_lock);
286 rand_meth_lock = NULL;
287 rand_inited = 0;
288}
289
290/* TODO(3.0): Do we need to handle this somehow in the FIPS module? */
291/*
292 * RAND_close_seed_files() ensures that any seed file descriptors are
293 * closed after use.
294 */
295void RAND_keep_random_devices_open(int keep)
296{
297 if (RUN_ONCE(&rand_init, do_rand_init))
298 rand_pool_keep_random_devices_open(keep);
299}
300
301/*
302 * RAND_poll() reseeds the default RNG using random input
303 *
304 * The random input is obtained from polling various entropy
305 * sources which depend on the operating system and are
306 * configurable via the --with-rand-seed configure option.
307 */
308int RAND_poll(void)
309{
310 int ret = 0;
311
312 const RAND_METHOD *meth = RAND_get_rand_method();
313
314 if (meth == NULL)
315 return 0;
316
317 if (meth == RAND_OpenSSL()) {
318 /* fill random pool and seed the master DRBG */
319 RAND_DRBG *drbg = RAND_DRBG_get0_master();
320
321 if (drbg == NULL)
322 return 0;
323
324 rand_drbg_lock(drbg);
325 ret = rand_drbg_restart(drbg, NULL, 0, 0);
326 rand_drbg_unlock(drbg);
327
328 return ret;
329
330 } else {
331 RAND_POOL *pool = NULL;
332
333 /* fill random pool and seed the current legacy RNG */
334 pool = rand_pool_new(RAND_DRBG_STRENGTH, 1,
335 (RAND_DRBG_STRENGTH + 7) / 8,
336 RAND_POOL_MAX_LENGTH);
337 if (pool == NULL)
338 return 0;
339
340 if (rand_pool_acquire_entropy(pool) == 0)
341 goto err;
342
343 if (meth->add == NULL
344 || meth->add(rand_pool_buffer(pool),
345 rand_pool_length(pool),
346 (rand_pool_entropy(pool) / 8.0)) == 0)
347 goto err;
348
349 ret = 1;
350
351 err:
352 rand_pool_free(pool);
353 }
354
355 return ret;
356}
357#endif /* FIPS_MODE */
358
359/*
360 * Allocate memory and initialize a new random pool
361 */
362
363RAND_POOL *rand_pool_new(int entropy_requested, int secure,
364 size_t min_len, size_t max_len)
365{
366 RAND_POOL *pool = OPENSSL_zalloc(sizeof(*pool));
367 size_t min_alloc_size = RAND_POOL_MIN_ALLOCATION(secure);
368
369 if (pool == NULL) {
370 RANDerr(RAND_F_RAND_POOL_NEW, ERR_R_MALLOC_FAILURE);
371 return NULL;
372 }
373
374 pool->min_len = min_len;
375 pool->max_len = (max_len > RAND_POOL_MAX_LENGTH) ?
376 RAND_POOL_MAX_LENGTH : max_len;
377 pool->alloc_len = min_len < min_alloc_size ? min_alloc_size : min_len;
378 if (pool->alloc_len > pool->max_len)
379 pool->alloc_len = pool->max_len;
380
381 if (secure)
382 pool->buffer = OPENSSL_secure_zalloc(pool->alloc_len);
383 else
384 pool->buffer = OPENSSL_zalloc(pool->alloc_len);
385
386 if (pool->buffer == NULL) {
387 RANDerr(RAND_F_RAND_POOL_NEW, ERR_R_MALLOC_FAILURE);
388 goto err;
389 }
390
391 pool->entropy_requested = entropy_requested;
392 pool->secure = secure;
393
394 return pool;
395
396err:
397 OPENSSL_free(pool);
398 return NULL;
399}
400
401/*
402 * Attach new random pool to the given buffer
403 *
404 * This function is intended to be used only for feeding random data
405 * provided by RAND_add() and RAND_seed() into the <master> DRBG.
406 */
407RAND_POOL *rand_pool_attach(const unsigned char *buffer, size_t len,
408 size_t entropy)
409{
410 RAND_POOL *pool = OPENSSL_zalloc(sizeof(*pool));
411
412 if (pool == NULL) {
413 RANDerr(RAND_F_RAND_POOL_ATTACH, ERR_R_MALLOC_FAILURE);
414 return NULL;
415 }
416
417 /*
418 * The const needs to be cast away, but attached buffers will not be
419 * modified (in contrary to allocated buffers which are zeroed and
420 * freed in the end).
421 */
422 pool->buffer = (unsigned char *) buffer;
423 pool->len = len;
424
425 pool->attached = 1;
426
427 pool->min_len = pool->max_len = pool->alloc_len = pool->len;
428 pool->entropy = entropy;
429
430 return pool;
431}
432
433/*
434 * Free |pool|, securely erasing its buffer.
435 */
436void rand_pool_free(RAND_POOL *pool)
437{
438 if (pool == NULL)
439 return;
440
441 /*
442 * Although it would be advisable from a cryptographical viewpoint,
443 * we are not allowed to clear attached buffers, since they are passed
444 * to rand_pool_attach() as `const unsigned char*`.
445 * (see corresponding comment in rand_pool_attach()).
446 */
447 if (!pool->attached) {
448 if (pool->secure)
449 OPENSSL_secure_clear_free(pool->buffer, pool->alloc_len);
450 else
451 OPENSSL_clear_free(pool->buffer, pool->alloc_len);
452 }
453
454 OPENSSL_free(pool);
455}
456
457/*
458 * Return the |pool|'s buffer to the caller (readonly).
459 */
460const unsigned char *rand_pool_buffer(RAND_POOL *pool)
461{
462 return pool->buffer;
463}
464
465/*
466 * Return the |pool|'s entropy to the caller.
467 */
468size_t rand_pool_entropy(RAND_POOL *pool)
469{
470 return pool->entropy;
471}
472
473/*
474 * Return the |pool|'s buffer length to the caller.
475 */
476size_t rand_pool_length(RAND_POOL *pool)
477{
478 return pool->len;
479}
480
481/*
482 * Detach the |pool| buffer and return it to the caller.
483 * It's the responsibility of the caller to free the buffer
484 * using OPENSSL_secure_clear_free() or to re-attach it
485 * again to the pool using rand_pool_reattach().
486 */
487unsigned char *rand_pool_detach(RAND_POOL *pool)
488{
489 unsigned char *ret = pool->buffer;
490 pool->buffer = NULL;
491 pool->entropy = 0;
492 return ret;
493}
494
495/*
496 * Re-attach the |pool| buffer. It is only allowed to pass
497 * the |buffer| which was previously detached from the same pool.
498 */
499void rand_pool_reattach(RAND_POOL *pool, unsigned char *buffer)
500{
501 pool->buffer = buffer;
502 OPENSSL_cleanse(pool->buffer, pool->len);
503 pool->len = 0;
504}
505
506/*
507 * If |entropy_factor| bits contain 1 bit of entropy, how many bytes does one
508 * need to obtain at least |bits| bits of entropy?
509 */
510#define ENTROPY_TO_BYTES(bits, entropy_factor) \
511 (((bits) * (entropy_factor) + 7) / 8)
512
513
514/*
515 * Checks whether the |pool|'s entropy is available to the caller.
516 * This is the case when entropy count and buffer length are high enough.
517 * Returns
518 *
519 * |entropy| if the entropy count and buffer size is large enough
520 * 0 otherwise
521 */
522size_t rand_pool_entropy_available(RAND_POOL *pool)
523{
524 if (pool->entropy < pool->entropy_requested)
525 return 0;
526
527 if (pool->len < pool->min_len)
528 return 0;
529
530 return pool->entropy;
531}
532
533/*
534 * Returns the (remaining) amount of entropy needed to fill
535 * the random pool.
536 */
537
538size_t rand_pool_entropy_needed(RAND_POOL *pool)
539{
540 if (pool->entropy < pool->entropy_requested)
541 return pool->entropy_requested - pool->entropy;
542
543 return 0;
544}
545
546/* Increase the allocation size -- not usable for an attached pool */
547static int rand_pool_grow(RAND_POOL *pool, size_t len)
548{
549 if (len > pool->alloc_len - pool->len) {
550 unsigned char *p;
551 const size_t limit = pool->max_len / 2;
552 size_t newlen = pool->alloc_len;
553
554 if (pool->attached || len > pool->max_len - pool->len) {
555 RANDerr(RAND_F_RAND_POOL_GROW, ERR_R_INTERNAL_ERROR);
556 return 0;
557 }
558
559 do
560 newlen = newlen < limit ? newlen * 2 : pool->max_len;
561 while (len > newlen - pool->len);
562
563 if (pool->secure)
564 p = OPENSSL_secure_zalloc(newlen);
565 else
566 p = OPENSSL_zalloc(newlen);
567 if (p == NULL) {
568 RANDerr(RAND_F_RAND_POOL_GROW, ERR_R_MALLOC_FAILURE);
569 return 0;
570 }
571 memcpy(p, pool->buffer, pool->len);
572 if (pool->secure)
573 OPENSSL_secure_clear_free(pool->buffer, pool->alloc_len);
574 else
575 OPENSSL_clear_free(pool->buffer, pool->alloc_len);
576 pool->buffer = p;
577 pool->alloc_len = newlen;
578 }
579 return 1;
580}
581
582/*
583 * Returns the number of bytes needed to fill the pool, assuming
584 * the input has 1 / |entropy_factor| entropy bits per data bit.
585 * In case of an error, 0 is returned.
586 */
587
588size_t rand_pool_bytes_needed(RAND_POOL *pool, unsigned int entropy_factor)
589{
590 size_t bytes_needed;
591 size_t entropy_needed = rand_pool_entropy_needed(pool);
592
593 if (entropy_factor < 1) {
594 RANDerr(RAND_F_RAND_POOL_BYTES_NEEDED, RAND_R_ARGUMENT_OUT_OF_RANGE);
595 return 0;
596 }
597
598 bytes_needed = ENTROPY_TO_BYTES(entropy_needed, entropy_factor);
599
600 if (bytes_needed > pool->max_len - pool->len) {
601 /* not enough space left */
602 RANDerr(RAND_F_RAND_POOL_BYTES_NEEDED, RAND_R_RANDOM_POOL_OVERFLOW);
603 return 0;
604 }
605
606 if (pool->len < pool->min_len &&
607 bytes_needed < pool->min_len - pool->len)
608 /* to meet the min_len requirement */
609 bytes_needed = pool->min_len - pool->len;
610
611 /*
612 * Make sure the buffer is large enough for the requested amount
613 * of data. This guarantees that existing code patterns where
614 * rand_pool_add_begin, rand_pool_add_end or rand_pool_add
615 * are used to collect entropy data without any error handling
616 * whatsoever, continue to be valid.
617 * Furthermore if the allocation here fails once, make sure that
618 * we don't fall back to a less secure or even blocking random source,
619 * as that could happen by the existing code patterns.
620 * This is not a concern for additional data, therefore that
621 * is not needed if rand_pool_grow fails in other places.
622 */
623 if (!rand_pool_grow(pool, bytes_needed)) {
624 /* persistent error for this pool */
625 pool->max_len = pool->len = 0;
626 return 0;
627 }
628
629 return bytes_needed;
630}
631
632/* Returns the remaining number of bytes available */
633size_t rand_pool_bytes_remaining(RAND_POOL *pool)
634{
635 return pool->max_len - pool->len;
636}
637
638/*
639 * Add random bytes to the random pool.
640 *
641 * It is expected that the |buffer| contains |len| bytes of
642 * random input which contains at least |entropy| bits of
643 * randomness.
644 *
645 * Returns 1 if the added amount is adequate, otherwise 0
646 */
647int rand_pool_add(RAND_POOL *pool,
648 const unsigned char *buffer, size_t len, size_t entropy)
649{
650 if (len > pool->max_len - pool->len) {
651 RANDerr(RAND_F_RAND_POOL_ADD, RAND_R_ENTROPY_INPUT_TOO_LONG);
652 return 0;
653 }
654
655 if (pool->buffer == NULL) {
656 RANDerr(RAND_F_RAND_POOL_ADD, ERR_R_INTERNAL_ERROR);
657 return 0;
658 }
659
660 if (len > 0) {
661 /*
662 * This is to protect us from accidentally passing the buffer
663 * returned from rand_pool_add_begin.
664 * The check for alloc_len makes sure we do not compare the
665 * address of the end of the allocated memory to something
666 * different, since that comparison would have an
667 * indeterminate result.
668 */
669 if (pool->alloc_len > pool->len && pool->buffer + pool->len == buffer) {
670 RANDerr(RAND_F_RAND_POOL_ADD, ERR_R_INTERNAL_ERROR);
671 return 0;
672 }
673 /*
674 * We have that only for cases when a pool is used to collect
675 * additional data.
676 * For entropy data, as long as the allocation request stays within
677 * the limits given by rand_pool_bytes_needed this rand_pool_grow
678 * below is guaranteed to succeed, thus no allocation happens.
679 */
680 if (!rand_pool_grow(pool, len))
681 return 0;
682 memcpy(pool->buffer + pool->len, buffer, len);
683 pool->len += len;
684 pool->entropy += entropy;
685 }
686
687 return 1;
688}
689
690/*
691 * Start to add random bytes to the random pool in-place.
692 *
693 * Reserves the next |len| bytes for adding random bytes in-place
694 * and returns a pointer to the buffer.
695 * The caller is allowed to copy up to |len| bytes into the buffer.
696 * If |len| == 0 this is considered a no-op and a NULL pointer
697 * is returned without producing an error message.
698 *
699 * After updating the buffer, rand_pool_add_end() needs to be called
700 * to finish the udpate operation (see next comment).
701 */
702unsigned char *rand_pool_add_begin(RAND_POOL *pool, size_t len)
703{
704 if (len == 0)
705 return NULL;
706
707 if (len > pool->max_len - pool->len) {
708 RANDerr(RAND_F_RAND_POOL_ADD_BEGIN, RAND_R_RANDOM_POOL_OVERFLOW);
709 return NULL;
710 }
711
712 if (pool->buffer == NULL) {
713 RANDerr(RAND_F_RAND_POOL_ADD_BEGIN, ERR_R_INTERNAL_ERROR);
714 return NULL;
715 }
716
717 /*
718 * As long as the allocation request stays within the limits given
719 * by rand_pool_bytes_needed this rand_pool_grow below is guaranteed
720 * to succeed, thus no allocation happens.
721 * We have that only for cases when a pool is used to collect
722 * additional data. Then the buffer might need to grow here,
723 * and of course the caller is responsible to check the return
724 * value of this function.
725 */
726 if (!rand_pool_grow(pool, len))
727 return NULL;
728
729 return pool->buffer + pool->len;
730}
731
732/*
733 * Finish to add random bytes to the random pool in-place.
734 *
735 * Finishes an in-place update of the random pool started by
736 * rand_pool_add_begin() (see previous comment).
737 * It is expected that |len| bytes of random input have been added
738 * to the buffer which contain at least |entropy| bits of randomness.
739 * It is allowed to add less bytes than originally reserved.
740 */
741int rand_pool_add_end(RAND_POOL *pool, size_t len, size_t entropy)
742{
743 if (len > pool->alloc_len - pool->len) {
744 RANDerr(RAND_F_RAND_POOL_ADD_END, RAND_R_RANDOM_POOL_OVERFLOW);
745 return 0;
746 }
747
748 if (len > 0) {
749 pool->len += len;
750 pool->entropy += entropy;
751 }
752
753 return 1;
754}
755
756#ifndef FIPS_MODE
757int RAND_set_rand_method(const RAND_METHOD *meth)
758{
759 if (!RUN_ONCE(&rand_init, do_rand_init))
760 return 0;
761
762 CRYPTO_THREAD_write_lock(rand_meth_lock);
763# ifndef OPENSSL_NO_ENGINE
764 ENGINE_finish(funct_ref);
765 funct_ref = NULL;
766# endif
767 default_RAND_meth = meth;
768 CRYPTO_THREAD_unlock(rand_meth_lock);
769 return 1;
770}
771#endif
772
773const RAND_METHOD *RAND_get_rand_method(void)
774{
775#ifdef FIPS_MODE
776 return NULL;
777#else
778 const RAND_METHOD *tmp_meth = NULL;
779
780 if (!RUN_ONCE(&rand_init, do_rand_init))
781 return NULL;
782
783 CRYPTO_THREAD_write_lock(rand_meth_lock);
784 if (default_RAND_meth == NULL) {
785# ifndef OPENSSL_NO_ENGINE
786 ENGINE *e;
787
788 /* If we have an engine that can do RAND, use it. */
789 if ((e = ENGINE_get_default_RAND()) != NULL
790 && (tmp_meth = ENGINE_get_RAND(e)) != NULL) {
791 funct_ref = e;
792 default_RAND_meth = tmp_meth;
793 } else {
794 ENGINE_finish(e);
795 default_RAND_meth = &rand_meth;
796 }
797# else
798 default_RAND_meth = &rand_meth;
799# endif
800 }
801 tmp_meth = default_RAND_meth;
802 CRYPTO_THREAD_unlock(rand_meth_lock);
803 return tmp_meth;
804#endif
805}
806
807#if !defined(OPENSSL_NO_ENGINE) && !defined(FIPS_MODE)
808int RAND_set_rand_engine(ENGINE *engine)
809{
810 const RAND_METHOD *tmp_meth = NULL;
811
812 if (!RUN_ONCE(&rand_init, do_rand_init))
813 return 0;
814
815 if (engine != NULL) {
816 if (!ENGINE_init(engine))
817 return 0;
818 tmp_meth = ENGINE_get_RAND(engine);
819 if (tmp_meth == NULL) {
820 ENGINE_finish(engine);
821 return 0;
822 }
823 }
824 CRYPTO_THREAD_write_lock(rand_engine_lock);
825 /* This function releases any prior ENGINE so call it first */
826 RAND_set_rand_method(tmp_meth);
827 funct_ref = engine;
828 CRYPTO_THREAD_unlock(rand_engine_lock);
829 return 1;
830}
831#endif
832
833void RAND_seed(const void *buf, int num)
834{
835 const RAND_METHOD *meth = RAND_get_rand_method();
836
837 if (meth != NULL && meth->seed != NULL)
838 meth->seed(buf, num);
839}
840
841void RAND_add(const void *buf, int num, double randomness)
842{
843 const RAND_METHOD *meth = RAND_get_rand_method();
844
845 if (meth != NULL && meth->add != NULL)
846 meth->add(buf, num, randomness);
847}
848
849/*
850 * This function is not part of RAND_METHOD, so if we're not using
851 * the default method, then just call RAND_bytes(). Otherwise make
852 * sure we're instantiated and use the private DRBG.
853 */
854int rand_priv_bytes_ex(OPENSSL_CTX *ctx, unsigned char *buf, int num)
855{
856 RAND_DRBG *drbg;
857 const RAND_METHOD *meth = RAND_get_rand_method();
858
859 if (meth != NULL && meth != RAND_OpenSSL()) {
860 if (meth->bytes != NULL)
861 return meth->bytes(buf, num);
862 RANDerr(RAND_F_RAND_PRIV_BYTES_EX, RAND_R_FUNC_NOT_IMPLEMENTED);
863 return -1;
864 }
865
866 drbg = OPENSSL_CTX_get0_private_drbg(ctx);
867 if (drbg != NULL)
868 return RAND_DRBG_bytes(drbg, buf, num);
869
870 return 0;
871}
872
873int RAND_priv_bytes(unsigned char *buf, int num)
874{
875 return rand_priv_bytes_ex(NULL, buf, num);
876}
877
878int rand_bytes_ex(OPENSSL_CTX *ctx, unsigned char *buf, int num)
879{
880 RAND_DRBG *drbg;
881 const RAND_METHOD *meth = RAND_get_rand_method();
882
883 if (meth != NULL && meth != RAND_OpenSSL()) {
884 if (meth->bytes != NULL)
885 return meth->bytes(buf, num);
886 RANDerr(RAND_F_RAND_BYTES_EX, RAND_R_FUNC_NOT_IMPLEMENTED);
887 return -1;
888 }
889
890 drbg = OPENSSL_CTX_get0_public_drbg(ctx);
891 if (drbg != NULL)
892 return RAND_DRBG_bytes(drbg, buf, num);
893
894 return 0;
895}
896
897int RAND_bytes(unsigned char *buf, int num)
898{
899 return rand_bytes_ex(NULL, buf, num);
900}
901
902#if !defined(OPENSSL_NO_DEPRECATED_1_1_0) && !defined(FIPS_MODE)
903int RAND_pseudo_bytes(unsigned char *buf, int num)
904{
905 const RAND_METHOD *meth = RAND_get_rand_method();
906
907 if (meth != NULL && meth->pseudorand != NULL)
908 return meth->pseudorand(buf, num);
909 RANDerr(RAND_F_RAND_PSEUDO_BYTES, RAND_R_FUNC_NOT_IMPLEMENTED);
910 return -1;
911}
912#endif
913
914int RAND_status(void)
915{
916 const RAND_METHOD *meth = RAND_get_rand_method();
917
918 if (meth != NULL && meth->status != NULL)
919 return meth->status();
920 return 0;
921}
922