1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
|
/*
* Copyright 1995-2020 The OpenSSL Project Authors. All Rights Reserved.
*
* Licensed under the Apache License 2.0 (the "License"). You may not use
* this file except in compliance with the License. You can obtain a copy
* in the file LICENSE in the source distribution or at
* https://www.openssl.org/source/license.html
*/
#include <stdio.h>
#include <time.h>
#include "internal/cryptlib.h"
#include <openssl/opensslconf.h>
#include "crypto/rand.h"
#include <openssl/engine.h>
#include "internal/thread_once.h"
#include "rand_local.h"
#include "e_os.h"
#ifndef FIPS_MODULE
# ifndef OPENSSL_NO_ENGINE
/* non-NULL if default_RAND_meth is ENGINE-provided */
static ENGINE *funct_ref;
static CRYPTO_RWLOCK *rand_engine_lock;
# endif
static CRYPTO_RWLOCK *rand_meth_lock;
static const RAND_METHOD *default_RAND_meth;
static CRYPTO_ONCE rand_init = CRYPTO_ONCE_STATIC_INIT;
static int rand_inited = 0;
#endif /* FIPS_MODULE */
#ifdef OPENSSL_RAND_SEED_RDTSC
/*
* IMPORTANT NOTE: It is not currently possible to use this code
* because we are not sure about the amount of randomness it provides.
* Some SP900 tests have been run, but there is internal skepticism.
* So for now this code is not used.
*/
# error "RDTSC enabled? Should not be possible!"
/*
* Acquire entropy from high-speed clock
*
* Since we get some randomness from the low-order bits of the
* high-speed clock, it can help.
*
* Returns the total entropy count, if it exceeds the requested
* entropy count. Otherwise, returns an entropy count of 0.
*/
size_t rand_acquire_entropy_from_tsc(RAND_POOL *pool)
{
unsigned char c;
int i;
if ((OPENSSL_ia32cap_P[0] & (1 << 4)) != 0) {
for (i = 0; i < TSC_READ_COUNT; i++) {
c = (unsigned char)(OPENSSL_rdtsc() & 0xFF);
rand_pool_add(pool, &c, 1, 4);
}
}
return rand_pool_entropy_available(pool);
}
#endif
#ifdef OPENSSL_RAND_SEED_RDCPU
size_t OPENSSL_ia32_rdseed_bytes(unsigned char *buf, size_t len);
size_t OPENSSL_ia32_rdrand_bytes(unsigned char *buf, size_t len);
/*
* Acquire entropy using Intel-specific cpu instructions
*
* Uses the RDSEED instruction if available, otherwise uses
* RDRAND if available.
*
* For the differences between RDSEED and RDRAND, and why RDSEED
* is the preferred choice, see https://goo.gl/oK3KcN
*
* Returns the total entropy count, if it exceeds the requested
* entropy count. Otherwise, returns an entropy count of 0.
*/
size_t rand_acquire_entropy_from_cpu(RAND_POOL *pool)
{
size_t bytes_needed;
unsigned char *buffer;
bytes_needed = rand_pool_bytes_needed(pool, 1 /*entropy_factor*/);
if (bytes_needed > 0) {
buffer = rand_pool_add_begin(pool, bytes_needed);
if (buffer != NULL) {
/* Whichever comes first, use RDSEED, RDRAND or nothing */
if ((OPENSSL_ia32cap_P[2] & (1 << 18)) != 0) {
if (OPENSSL_ia32_rdseed_bytes(buffer, bytes_needed)
== bytes_needed) {
rand_pool_add_end(pool, bytes_needed, 8 * bytes_needed);
}
} else if ((OPENSSL_ia32cap_P[1] & (1 << (62 - 32))) != 0) {
if (OPENSSL_ia32_rdrand_bytes(buffer, bytes_needed)
== bytes_needed) {
rand_pool_add_end(pool, bytes_needed, 8 * bytes_needed);
}
} else {
rand_pool_add_end(pool, 0, 0);
}
}
}
return rand_pool_entropy_available(pool);
}
#endif
#if 0
/*
* Implements the get_entropy() callback (see RAND_DRBG_set_callbacks())
*
* If the DRBG has a parent, then the required amount of entropy input
* is fetched using the parent's RAND_DRBG_generate().
*
* Otherwise, the entropy is polled from the system entropy sources
* using rand_pool_acquire_entropy().
*
* If a random pool has been added to the DRBG using RAND_add(), then
* its entropy will be used up first.
*/
size_t rand_drbg_get_entropy(RAND_DRBG *drbg,
unsigned char **pout,
int entropy, size_t min_len, size_t max_len,
int prediction_resistance)
{
size_t ret = 0;
size_t entropy_available = 0;
RAND_POOL *pool;
if (drbg->parent != NULL && drbg->strength > drbg->parent->strength) {
/*
* We currently don't support the algorithm from NIST SP 800-90C
* 10.1.2 to use a weaker DRBG as source
*/
RANDerr(RAND_F_RAND_DRBG_GET_ENTROPY, RAND_R_PARENT_STRENGTH_TOO_WEAK);
return 0;
}
if (drbg->seed_pool != NULL) {
pool = drbg->seed_pool;
pool->entropy_requested = entropy;
} else {
pool = rand_pool_new(entropy, drbg->secure, min_len, max_len);
if (pool == NULL)
return 0;
}
if (drbg->parent != NULL) {
size_t bytes_needed = rand_pool_bytes_needed(pool, 1 /*entropy_factor*/);
unsigned char *buffer = rand_pool_add_begin(pool, bytes_needed);
if (buffer != NULL) {
size_t bytes = 0;
/*
* Get random data from parent. Include our address as additional input,
* in order to provide some additional distinction between different
* DRBG child instances.
* Our lock is already held, but we need to lock our parent before
* generating bits from it. (Note: taking the lock will be a no-op
* if locking if drbg->parent->lock == NULL.)
*/
rand_drbg_lock(drbg->parent);
if (RAND_DRBG_generate(drbg->parent,
buffer, bytes_needed,
prediction_resistance,
(unsigned char *)&drbg, sizeof(drbg)) != 0)
bytes = bytes_needed;
drbg->reseed_next_counter
= tsan_load(&drbg->parent->reseed_prop_counter);
rand_drbg_unlock(drbg->parent);
rand_pool_add_end(pool, bytes, 8 * bytes);
entropy_available = rand_pool_entropy_available(pool);
}
} else {
/* Get entropy by polling system entropy sources. */
entropy_available = rand_pool_acquire_entropy(pool);
}
if (entropy_available > 0) {
ret = rand_pool_length(pool);
*pout = rand_pool_detach(pool);
}
if (drbg->seed_pool == NULL)
rand_pool_free(pool);
return ret;
}
/*
* Implements the cleanup_entropy() callback (see RAND_DRBG_set_callbacks())
*
*/
void rand_drbg_cleanup_entropy(RAND_DRBG *drbg,
unsigned char *out, size_t outlen)
{
if (drbg->seed_pool == NULL) {
if (drbg->secure)
OPENSSL_secure_clear_free(out, outlen);
else
OPENSSL_clear_free(out, outlen);
}
}
/*
* Generate additional data that can be used for the drbg. The data does
* not need to contain entropy, but it's useful if it contains at least
* some bits that are unpredictable.
*
* Returns 0 on failure.
*
* On success it allocates a buffer at |*pout| and returns the length of
* the data. The buffer should get freed using OPENSSL_secure_clear_free().
*/
size_t rand_drbg_get_additional_data(RAND_POOL *pool, unsigned char **pout)
{
size_t ret = 0;
if (rand_pool_add_additional_data(pool) == 0)
goto err;
ret = rand_pool_length(pool);
*pout = rand_pool_detach(pool);
err:
return ret;
}
void rand_drbg_cleanup_additional_data(RAND_POOL *pool, unsigned char *out)
{
rand_pool_reattach(pool, out);
}
#endif
#ifndef FIPS_MODULE
DEFINE_RUN_ONCE_STATIC(do_rand_init)
{
# ifndef OPENSSL_NO_ENGINE
rand_engine_lock = CRYPTO_THREAD_lock_new();
if (rand_engine_lock == NULL)
return 0;
# endif
rand_meth_lock = CRYPTO_THREAD_lock_new();
if (rand_meth_lock == NULL)
goto err;
if (!rand_pool_init())
goto err;
rand_inited = 1;
return 1;
err:
CRYPTO_THREAD_lock_free(rand_meth_lock);
rand_meth_lock = NULL;
# ifndef OPENSSL_NO_ENGINE
CRYPTO_THREAD_lock_free(rand_engine_lock);
rand_engine_lock = NULL;
# endif
return 0;
}
void rand_cleanup_int(void)
{
const RAND_METHOD *meth = default_RAND_meth;
if (!rand_inited)
return;
if (meth != NULL && meth->cleanup != NULL)
meth->cleanup();
RAND_set_rand_method(NULL);
rand_pool_cleanup();
# ifndef OPENSSL_NO_ENGINE
CRYPTO_THREAD_lock_free(rand_engine_lock);
rand_engine_lock = NULL;
# endif
CRYPTO_THREAD_lock_free(rand_meth_lock);
rand_meth_lock = NULL;
rand_inited = 0;
}
/* TODO(3.0): Do we need to handle this somehow in the FIPS module? */
/*
* RAND_close_seed_files() ensures that any seed file descriptors are
* closed after use.
*/
void RAND_keep_random_devices_open(int keep)
{
if (RUN_ONCE(&rand_init, do_rand_init))
rand_pool_keep_random_devices_open(keep);
}
/*
* RAND_poll() reseeds the default RNG using random input
*
* The random input is obtained from polling various entropy
* sources which depend on the operating system and are
* configurable via the --with-rand-seed configure option.
*/
int RAND_poll(void)
{
int ret = 0;
const RAND_METHOD *meth = RAND_get_rand_method();
if (meth == NULL)
return 0;
if (meth == RAND_OpenSSL()) {
/* fill random pool and seed the master DRBG */
RAND_DRBG *drbg = RAND_DRBG_get0_master();
if (drbg == NULL)
return 0;
#if 0
ret = rand_drbg_restart(drbg, NULL, 0, 0);
#endif
return ret;
} else {
RAND_POOL *pool = NULL;
/* fill random pool and seed the current legacy RNG */
pool = rand_pool_new(RAND_DRBG_STRENGTH, 1,
(RAND_DRBG_STRENGTH + 7) / 8,
RAND_POOL_MAX_LENGTH);
if (pool == NULL)
return 0;
#if 0
if (rand_pool_acquire_entropy(pool) == 0)
goto err;
#endif
if (meth->add == NULL
|| meth->add(rand_pool_buffer(pool),
rand_pool_length(pool),
(rand_pool_entropy(pool) / 8.0)) == 0)
goto err;
ret = 1;
err:
rand_pool_free(pool);
}
return ret;
}
int RAND_set_rand_method(const RAND_METHOD *meth)
{
if (!RUN_ONCE(&rand_init, do_rand_init))
return 0;
CRYPTO_THREAD_write_lock(rand_meth_lock);
# ifndef OPENSSL_NO_ENGINE
ENGINE_finish(funct_ref);
funct_ref = NULL
|