2 * Copyright 1995-2017 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
12 #include "internal/cryptlib.h"
13 #include <openssl/opensslconf.h>
14 #include "internal/rand_int.h"
15 #include <openssl/engine.h>
16 #include "internal/thread_once.h"
19 #ifndef OPENSSL_NO_ENGINE
20 /* non-NULL if default_RAND_meth is ENGINE-provided */
21 static ENGINE *funct_ref;
22 static CRYPTO_RWLOCK *rand_engine_lock;
24 static CRYPTO_RWLOCK *rand_meth_lock;
25 static const RAND_METHOD *default_RAND_meth;
26 static CRYPTO_ONCE rand_init = CRYPTO_ONCE_STATIC_INIT;
27 RAND_BYTES_BUFFER rand_bytes;
30 #ifdef OPENSSL_RAND_SEED_RDTSC
32 * IMPORTANT NOTE: It is not currently possible to use this code
33 * because we are not sure about the amount of randomness it provides.
34 * Some SP900 tests have been run, but there is internal skepticism.
35 * So for now this code is not used.
37 # error "RDTSC enabled? Should not be possible!"
40 * Since we get some randomness from the low-order bits of the
41 * high-speec clock, it can help. But don't return a status since
42 * it's not sufficient to indicate whether or not the seeding was
45 void rand_read_tsc(RAND_poll_fn cb, void *arg)
50 if ((OPENSSL_ia32cap_P[0] & (1 << 4)) != 0) {
51 for (i = 0; i < TSC_READ_COUNT; i++) {
52 c = (unsigned char)(OPENSSL_rdtsc() & 0xFF);
59 #ifdef OPENSSL_RAND_SEED_RDCPU
60 size_t OPENSSL_ia32_rdseed_bytes(char *buf, size_t len);
61 size_t OPENSSL_ia32_rdrand_bytes(char *buf, size_t len);
63 extern unsigned int OPENSSL_ia32cap_P[];
65 int rand_read_cpu(RAND_poll_fn cb, void *arg)
67 char buff[RANDOMNESS_NEEDED];
69 /* If RDSEED is available, use that. */
70 if ((OPENSSL_ia32cap_P[2] & (1 << 18)) != 0) {
71 if (OPENSSL_ia32_rdseed_bytes(buff, sizeof(buff)) == sizeof(buff)) {
72 cb(arg, buff, (int)sizeof(buff), sizeof(buff));
77 /* Second choice is RDRAND. */
78 if ((OPENSSL_ia32cap_P[1] & (1 << (62 - 32))) != 0) {
79 if (OPENSSL_ia32_rdrand_bytes(buff, sizeof(buff)) == sizeof(buff)) {
80 cb(arg, buff, (int)sizeof(buff), sizeof(buff));
91 * DRBG has two sets of callbacks; we only discuss the "entropy" one
92 * here. When the DRBG needs additional randomness bits (called entropy
93 * in the NIST document), it calls the get_entropy callback which fills in
94 * a pointer and returns the number of bytes. When the DRBG is finished with
95 * the buffer, it calls the cleanup_entropy callback, with the value of
96 * the buffer that the get_entropy callback filled in.
98 * Get entropy from the system, via RAND_poll if needed. The |entropy|
99 * is the bits of randomness required, and is expected to fit into a buffer
100 * of |min_len|..|max__len| size. We assume we're getting high-quality
101 * randomness from the system, and that |min_len| bytes will do.
103 size_t drbg_entropy_from_system(RAND_DRBG *drbg,
104 unsigned char **pout,
105 int entropy, size_t min_len, size_t max_len)
110 if (min_len > (size_t)drbg->size) {
111 /* Should not happen. See comment near RANDOMNESS_NEEDED. */
112 min_len = drbg->size;
116 /* Re-use what we have. */
117 *pout = drbg->randomness;
121 drbg->randomness = drbg->secure ? OPENSSL_secure_malloc(drbg->size)
122 : OPENSSL_malloc(drbg->size);
124 /* If we don't have enough, try to get more. */
125 CRYPTO_THREAD_write_lock(rand_bytes.lock);
126 for (i = RAND_POLL_RETRIES; rand_bytes.curr < min_len && --i >= 0; ) {
127 CRYPTO_THREAD_unlock(rand_bytes.lock);
129 CRYPTO_THREAD_write_lock(rand_bytes.lock);
132 /* Get desired amount, but no more than we have. */
133 if (min_len > rand_bytes.curr)
134 min_len = rand_bytes.curr;
136 memcpy(drbg->randomness, rand_bytes.buff, min_len);
138 /* Update amount left and shift it down. */
139 rand_bytes.curr -= min_len;
140 if (rand_bytes.curr != 0)
141 memmove(rand_bytes.buff, &rand_bytes.buff[min_len], rand_bytes.curr);
143 CRYPTO_THREAD_unlock(rand_bytes.lock);
144 *pout = drbg->randomness;
148 size_t drbg_entropy_from_parent(RAND_DRBG *drbg,
149 unsigned char **pout,
150 int entropy, size_t min_len, size_t max_len)
154 if (min_len > (size_t)drbg->size) {
155 /* Should not happen. See comment near RANDOMNESS_NEEDED. */
156 min_len = drbg->size;
159 drbg->randomness = drbg->secure ? OPENSSL_secure_malloc(drbg->size)
160 : OPENSSL_malloc(drbg->size);
162 /* Get random from parent, include our state as additional input. */
163 st = RAND_DRBG_generate(drbg->parent, drbg->randomness, min_len, 0,
164 (unsigned char *)drbg, sizeof(*drbg));
168 *pout = drbg->randomness;
172 void drbg_release_entropy(RAND_DRBG *drbg, unsigned char *out)
176 OPENSSL_secure_clear_free(drbg->randomness, drbg->size);
178 OPENSSL_clear_free(drbg->randomness, drbg->size);
179 drbg->randomness = NULL;
184 * Set up a global DRBG.
186 static int setup_drbg(RAND_DRBG *drbg)
190 drbg->lock = CRYPTO_THREAD_lock_new();
191 ret &= drbg->lock != NULL;
192 drbg->size = RANDOMNESS_NEEDED;
193 drbg->secure = CRYPTO_secure_malloc_initialized();
194 drbg->randomness = NULL;
195 /* If you change these parameters, see RANDOMNESS_NEEDED */
196 ret &= RAND_DRBG_set(drbg,
197 NID_aes_128_ctr, RAND_DRBG_FLAG_CTR_USE_DF) == 1;
198 ret &= RAND_DRBG_set_callbacks(drbg, drbg_entropy_from_system,
199 drbg_release_entropy, NULL, NULL) == 1;
203 static void free_drbg(RAND_DRBG *drbg)
205 CRYPTO_THREAD_lock_free(drbg->lock);
206 RAND_DRBG_uninstantiate(drbg);
214 DEFINE_RUN_ONCE_STATIC(do_rand_init)
218 #ifndef OPENSSL_NO_ENGINE
219 rand_engine_lock = CRYPTO_THREAD_lock_new();
220 ret &= rand_engine_lock != NULL;
222 rand_meth_lock = CRYPTO_THREAD_lock_new();
223 ret &= rand_meth_lock != NULL;
225 rand_bytes.lock = CRYPTO_THREAD_lock_new();
226 ret &= rand_bytes.lock != NULL;
228 rand_bytes.size = MAX_RANDOMNESS_HELD;
229 rand_bytes.secure = CRYPTO_secure_malloc_initialized();
230 rand_bytes.buff = rand_bytes.secure
231 ? OPENSSL_secure_malloc(rand_bytes.size)
232 : OPENSSL_malloc(rand_bytes.size);
233 ret &= rand_bytes.buff != NULL;
234 ret &= setup_drbg(&rand_drbg);
235 ret &= setup_drbg(&priv_drbg);
239 void rand_cleanup_int(void)
241 const RAND_METHOD *meth = default_RAND_meth;
243 if (meth != NULL && meth->cleanup != NULL)
245 RAND_set_rand_method(NULL);
246 #ifndef OPENSSL_NO_ENGINE
247 CRYPTO_THREAD_lock_free(rand_engine_lock);
249 CRYPTO_THREAD_lock_free(rand_meth_lock);
250 CRYPTO_THREAD_lock_free(rand_bytes.lock);
251 if (rand_bytes.secure)
252 OPENSSL_secure_clear_free(rand_bytes.buff, rand_bytes.size);
254 OPENSSL_clear_free(rand_bytes.buff, rand_bytes.size);
255 free_drbg(&rand_drbg);
256 free_drbg(&priv_drbg);
260 * RAND_poll_ex() gets a function pointer to call when it has random bytes.
261 * RAND_poll() sets the function pointer to be a wrapper that calls RAND_add().
263 static void call_rand_add(void* arg, const void *buf, int num, double r)
265 RAND_add(buf, num, r);
270 return RAND_poll_ex(call_rand_add, NULL);
273 int RAND_set_rand_method(const RAND_METHOD *meth)
275 if (!RUN_ONCE(&rand_init, do_rand_init))
278 CRYPTO_THREAD_write_lock(rand_meth_lock);
279 #ifndef OPENSSL_NO_ENGINE
280 ENGINE_finish(funct_ref);
283 default_RAND_meth = meth;
284 CRYPTO_THREAD_unlock(rand_meth_lock);
288 const RAND_METHOD *RAND_get_rand_method(void)
290 const RAND_METHOD *tmp_meth = NULL;
292 if (!RUN_ONCE(&rand_init, do_rand_init))
295 CRYPTO_THREAD_write_lock(rand_meth_lock);
296 if (default_RAND_meth == NULL) {
297 #ifndef OPENSSL_NO_ENGINE
300 /* If we have an engine that can do RAND, use it. */
301 if ((e = ENGINE_get_default_RAND()) != NULL
302 && (tmp_meth = ENGINE_get_RAND(e)) != NULL) {
304 default_RAND_meth = tmp_meth;
307 default_RAND_meth = &rand_meth;
310 default_RAND_meth = &rand_meth;
313 tmp_meth = default_RAND_meth;
314 CRYPTO_THREAD_unlock(rand_meth_lock);
318 #ifndef OPENSSL_NO_ENGINE
319 int RAND_set_rand_engine(ENGINE *engine)
321 const RAND_METHOD *tmp_meth = NULL;
323 if (!RUN_ONCE(&rand_init, do_rand_init))
326 if (engine != NULL) {
327 if (!ENGINE_init(engine))
329 tmp_meth = ENGINE_get_RAND(engine);
330 if (tmp_meth == NULL) {
331 ENGINE_finish(engine);
335 CRYPTO_THREAD_write_lock(rand_engine_lock);
336 /* This function releases any prior ENGINE so call it first */
337 RAND_set_rand_method(tmp_meth);
339 CRYPTO_THREAD_unlock(rand_engine_lock);
344 void RAND_seed(const void *buf, int num)
346 const RAND_METHOD *meth = RAND_get_rand_method();
348 if (meth->seed != NULL)
349 meth->seed(buf, num);
352 void RAND_add(const void *buf, int num, double randomness)
354 const RAND_METHOD *meth = RAND_get_rand_method();
356 if (meth->add != NULL)
357 meth->add(buf, num, randomness);
361 * This function is not part of RAND_METHOD, so if we're not using
362 * the default method, then just call RAND_bytes(). Otherwise make
363 * sure we're instantiated and use the private DRBG.
365 int RAND_priv_bytes(unsigned char *buf, int num)
367 const RAND_METHOD *meth = RAND_get_rand_method();
369 if (meth != RAND_OpenSSL())
370 return RAND_bytes(buf, num);
372 if (priv_drbg.state == DRBG_UNINITIALISED
373 && RAND_DRBG_instantiate(&priv_drbg, NULL, 0) == 0)
375 return RAND_DRBG_generate(&priv_drbg, buf, num, 0, NULL, 0);
379 int RAND_bytes(unsigned char *buf, int num)
381 const RAND_METHOD *meth = RAND_get_rand_method();
383 if (meth->bytes != NULL)
384 return meth->bytes(buf, num);
385 RANDerr(RAND_F_RAND_BYTES, RAND_R_FUNC_NOT_IMPLEMENTED);
389 #if OPENSSL_API_COMPAT < 0x10100000L
390 int RAND_pseudo_bytes(unsigned char *buf, int num)
392 const RAND_METHOD *meth = RAND_get_rand_method();
394 if (meth->pseudorand != NULL)
395 return meth->pseudorand(buf, num);
400 int RAND_status(void)
402 const RAND_METHOD *meth = RAND_get_rand_method();
404 if (meth->status != NULL)
405 return meth->status();