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_cb rand_add, 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);
53 rand_add(arg, &c, 1, 0.5);
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_cb rand_add, 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 rand_add(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 rand_add(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)
108 unsigned char *randomness;
110 if (min_len > (size_t)drbg->size) {
111 /* Should not happen. See comment near RANDOMNESS_NEEDED. */
112 min_len = drbg->size;
115 randomness = drbg->secure ? OPENSSL_secure_malloc(drbg->size)
116 : OPENSSL_malloc(drbg->size);
118 /* If we don't have enough, try to get more. */
119 CRYPTO_THREAD_write_lock(rand_bytes.lock);
120 for (i = RAND_POLL_RETRIES; rand_bytes.curr < min_len && --i >= 0; ) {
121 CRYPTO_THREAD_unlock(rand_bytes.lock);
123 CRYPTO_THREAD_write_lock(rand_bytes.lock);
126 /* Get desired amount, but no more than we have. */
127 if (min_len > rand_bytes.curr)
128 min_len = rand_bytes.curr;
130 memcpy(randomness, rand_bytes.buff, min_len);
131 /* Update amount left and shift it down. */
132 rand_bytes.curr -= min_len;
133 if (rand_bytes.curr != 0)
134 memmove(rand_bytes.buff, &rand_bytes.buff[min_len], rand_bytes.curr);
136 CRYPTO_THREAD_unlock(rand_bytes.lock);
141 size_t drbg_entropy_from_parent(RAND_DRBG *drbg,
142 unsigned char **pout,
143 int entropy, size_t min_len, size_t max_len)
146 unsigned char *randomness;
148 if (min_len > (size_t)drbg->size) {
149 /* Should not happen. See comment near RANDOMNESS_NEEDED. */
150 min_len = drbg->size;
153 randomness = drbg->secure ? OPENSSL_secure_malloc(drbg->size)
154 : OPENSSL_malloc(drbg->size);
156 /* Get random from parent, include our state as additional input. */
157 st = RAND_DRBG_generate(drbg->parent, randomness, min_len, 0,
158 (unsigned char *)drbg, sizeof(*drbg));
160 drbg_release_entropy(drbg, randomness, min_len);
167 void drbg_release_entropy(RAND_DRBG *drbg, unsigned char *out, size_t outlen)
170 OPENSSL_secure_clear_free(out, outlen);
172 OPENSSL_clear_free(out, outlen);
177 * Set up a global DRBG.
179 static int setup_drbg(RAND_DRBG *drbg)
183 drbg->lock = CRYPTO_THREAD_lock_new();
184 ret &= drbg->lock != NULL;
185 drbg->size = RANDOMNESS_NEEDED;
186 drbg->secure = CRYPTO_secure_malloc_initialized();
187 /* If you change these parameters, see RANDOMNESS_NEEDED */
188 ret &= RAND_DRBG_set(drbg,
189 NID_aes_128_ctr, RAND_DRBG_FLAG_CTR_USE_DF) == 1;
190 ret &= RAND_DRBG_set_callbacks(drbg, drbg_entropy_from_system,
191 drbg_release_entropy, NULL, NULL) == 1;
195 static void free_drbg(RAND_DRBG *drbg)
197 CRYPTO_THREAD_lock_free(drbg->lock);
198 RAND_DRBG_uninstantiate(drbg);
206 DEFINE_RUN_ONCE_STATIC(do_rand_init)
210 #ifndef OPENSSL_NO_ENGINE
211 rand_engine_lock = CRYPTO_THREAD_lock_new();
212 ret &= rand_engine_lock != NULL;
214 rand_meth_lock = CRYPTO_THREAD_lock_new();
215 ret &= rand_meth_lock != NULL;
217 rand_bytes.lock = CRYPTO_THREAD_lock_new();
218 ret &= rand_bytes.lock != NULL;
220 rand_bytes.size = MAX_RANDOMNESS_HELD;
221 rand_bytes.secure = CRYPTO_secure_malloc_initialized();
222 rand_bytes.buff = rand_bytes.secure
223 ? OPENSSL_secure_malloc(rand_bytes.size)
224 : OPENSSL_malloc(rand_bytes.size);
225 ret &= rand_bytes.buff != NULL;
226 ret &= setup_drbg(&rand_drbg);
227 ret &= setup_drbg(&priv_drbg);
231 void rand_cleanup_int(void)
233 const RAND_METHOD *meth = default_RAND_meth;
235 if (meth != NULL && meth->cleanup != NULL)
237 RAND_set_rand_method(NULL);
238 #ifndef OPENSSL_NO_ENGINE
239 CRYPTO_THREAD_lock_free(rand_engine_lock);
241 CRYPTO_THREAD_lock_free(rand_meth_lock);
242 CRYPTO_THREAD_lock_free(rand_bytes.lock);
243 if (rand_bytes.secure)
244 OPENSSL_secure_clear_free(rand_bytes.buff, rand_bytes.size);
246 OPENSSL_clear_free(rand_bytes.buff, rand_bytes.size);
247 free_drbg(&rand_drbg);
248 free_drbg(&priv_drbg);
252 * RAND_poll_ex() gets a function pointer to call when it has random bytes.
253 * RAND_poll() sets the function pointer to be a wrapper that calls RAND_add().
255 static void call_rand_add(void* arg, const void *buf, int num, double r)
257 RAND_add(buf, num, r);
262 return RAND_poll_ex(call_rand_add, NULL);
265 int RAND_set_rand_method(const RAND_METHOD *meth)
267 if (!RUN_ONCE(&rand_init, do_rand_init))
270 CRYPTO_THREAD_write_lock(rand_meth_lock);
271 #ifndef OPENSSL_NO_ENGINE
272 ENGINE_finish(funct_ref);
275 default_RAND_meth = meth;
276 CRYPTO_THREAD_unlock(rand_meth_lock);
280 const RAND_METHOD *RAND_get_rand_method(void)
282 const RAND_METHOD *tmp_meth = NULL;
284 if (!RUN_ONCE(&rand_init, do_rand_init))
287 CRYPTO_THREAD_write_lock(rand_meth_lock);
288 if (default_RAND_meth == NULL) {
289 #ifndef OPENSSL_NO_ENGINE
292 /* If we have an engine that can do RAND, use it. */
293 if ((e = ENGINE_get_default_RAND()) != NULL
294 && (tmp_meth = ENGINE_get_RAND(e)) != NULL) {
296 default_RAND_meth = tmp_meth;
299 default_RAND_meth = &rand_meth;
302 default_RAND_meth = &rand_meth;
305 tmp_meth = default_RAND_meth;
306 CRYPTO_THREAD_unlock(rand_meth_lock);
310 #ifndef OPENSSL_NO_ENGINE
311 int RAND_set_rand_engine(ENGINE *engine)
313 const RAND_METHOD *tmp_meth = NULL;
315 if (!RUN_ONCE(&rand_init, do_rand_init))
318 if (engine != NULL) {
319 if (!ENGINE_init(engine))
321 tmp_meth = ENGINE_get_RAND(engine);
322 if (tmp_meth == NULL) {
323 ENGINE_finish(engine);
327 CRYPTO_THREAD_write_lock(rand_engine_lock);
328 /* This function releases any prior ENGINE so call it first */
329 RAND_set_rand_method(tmp_meth);
331 CRYPTO_THREAD_unlock(rand_engine_lock);
336 void RAND_seed(const void *buf, int num)
338 const RAND_METHOD *meth = RAND_get_rand_method();
340 if (meth->seed != NULL)
341 meth->seed(buf, num);
344 void RAND_add(const void *buf, int num, double randomness)
346 const RAND_METHOD *meth = RAND_get_rand_method();
348 if (meth->add != NULL)
349 meth->add(buf, num, randomness);
353 * This function is not part of RAND_METHOD, so if we're not using
354 * the default method, then just call RAND_bytes(). Otherwise make
355 * sure we're instantiated and use the private DRBG.
357 int RAND_priv_bytes(unsigned char *buf, int num)
359 const RAND_METHOD *meth = RAND_get_rand_method();
361 if (meth != RAND_OpenSSL())
362 return RAND_bytes(buf, num);
364 if (priv_drbg.state == DRBG_UNINITIALISED
365 && RAND_DRBG_instantiate(&priv_drbg, NULL, 0) == 0)
367 return RAND_DRBG_generate(&priv_drbg, buf, num, 0, NULL, 0);
371 int RAND_bytes(unsigned char *buf, int num)
373 const RAND_METHOD *meth = RAND_get_rand_method();
375 if (meth->bytes != NULL)
376 return meth->bytes(buf, num);
377 RANDerr(RAND_F_RAND_BYTES, RAND_R_FUNC_NOT_IMPLEMENTED);
381 #if OPENSSL_API_COMPAT < 0x10100000L
382 int RAND_pseudo_bytes(unsigned char *buf, int num)
384 const RAND_METHOD *meth = RAND_get_rand_method();
386 if (meth->pseudorand != NULL)
387 return meth->pseudorand(buf, num);
392 int RAND_status(void)
394 const RAND_METHOD *meth = RAND_get_rand_method();
396 if (meth->status != NULL)
397 return meth->status();