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
);
180 DEFINE_RUN_ONCE_STATIC(do_rand_init
)
184 #ifndef OPENSSL_NO_ENGINE
185 rand_engine_lock
= CRYPTO_THREAD_lock_new();
186 ret
&= rand_engine_lock
!= NULL
;
188 rand_meth_lock
= CRYPTO_THREAD_lock_new();
189 ret
&= rand_meth_lock
!= NULL
;
191 rand_bytes
.lock
= CRYPTO_THREAD_lock_new();
192 ret
&= rand_bytes
.lock
!= NULL
;
194 rand_bytes
.size
= MAX_RANDOMNESS_HELD
;
195 rand_bytes
.secure
= CRYPTO_secure_malloc_initialized();
196 rand_bytes
.buff
= rand_bytes
.secure
197 ? OPENSSL_secure_malloc(rand_bytes
.size
)
198 : OPENSSL_malloc(rand_bytes
.size
);
199 ret
&= rand_bytes
.buff
!= NULL
;
203 void rand_cleanup_int(void)
205 const RAND_METHOD
*meth
= default_RAND_meth
;
207 if (meth
!= NULL
&& meth
->cleanup
!= NULL
)
209 RAND_set_rand_method(NULL
);
210 #ifndef OPENSSL_NO_ENGINE
211 CRYPTO_THREAD_lock_free(rand_engine_lock
);
213 CRYPTO_THREAD_lock_free(rand_meth_lock
);
214 CRYPTO_THREAD_lock_free(rand_bytes
.lock
);
215 if (rand_bytes
.secure
)
216 OPENSSL_secure_clear_free(rand_bytes
.buff
, rand_bytes
.size
);
218 OPENSSL_clear_free(rand_bytes
.buff
, rand_bytes
.size
);
222 * RAND_poll_ex() gets a function pointer to call when it has random bytes.
223 * RAND_poll() sets the function pointer to be a wrapper that calls RAND_add().
225 static void call_rand_add(void* arg
, const void *buf
, int num
, double r
)
227 RAND_add(buf
, num
, r
);
232 return RAND_poll_ex(call_rand_add
, NULL
);
235 int RAND_set_rand_method(const RAND_METHOD
*meth
)
237 if (!RUN_ONCE(&rand_init
, do_rand_init
))
240 CRYPTO_THREAD_write_lock(rand_meth_lock
);
241 #ifndef OPENSSL_NO_ENGINE
242 ENGINE_finish(funct_ref
);
245 default_RAND_meth
= meth
;
246 CRYPTO_THREAD_unlock(rand_meth_lock
);
250 const RAND_METHOD
*RAND_get_rand_method(void)
252 const RAND_METHOD
*tmp_meth
= NULL
;
254 if (!RUN_ONCE(&rand_init
, do_rand_init
))
257 CRYPTO_THREAD_write_lock(rand_meth_lock
);
258 if (default_RAND_meth
== NULL
) {
259 #ifndef OPENSSL_NO_ENGINE
262 /* If we have an engine that can do RAND, use it. */
263 if ((e
= ENGINE_get_default_RAND()) != NULL
264 && (tmp_meth
= ENGINE_get_RAND(e
)) != NULL
) {
266 default_RAND_meth
= tmp_meth
;
269 default_RAND_meth
= &rand_meth
;
272 default_RAND_meth
= &rand_meth
;
275 tmp_meth
= default_RAND_meth
;
276 CRYPTO_THREAD_unlock(rand_meth_lock
);
280 #ifndef OPENSSL_NO_ENGINE
281 int RAND_set_rand_engine(ENGINE
*engine
)
283 const RAND_METHOD
*tmp_meth
= NULL
;
285 if (!RUN_ONCE(&rand_init
, do_rand_init
))
288 if (engine
!= NULL
) {
289 if (!ENGINE_init(engine
))
291 tmp_meth
= ENGINE_get_RAND(engine
);
292 if (tmp_meth
== NULL
) {
293 ENGINE_finish(engine
);
297 CRYPTO_THREAD_write_lock(rand_engine_lock
);
298 /* This function releases any prior ENGINE so call it first */
299 RAND_set_rand_method(tmp_meth
);
301 CRYPTO_THREAD_unlock(rand_engine_lock
);
306 void RAND_seed(const void *buf
, int num
)
308 const RAND_METHOD
*meth
= RAND_get_rand_method();
310 if (meth
->seed
!= NULL
)
311 meth
->seed(buf
, num
);
314 void RAND_add(const void *buf
, int num
, double randomness
)
316 const RAND_METHOD
*meth
= RAND_get_rand_method();
318 if (meth
->add
!= NULL
)
319 meth
->add(buf
, num
, randomness
);
323 * This function is not part of RAND_METHOD, so if we're not using
324 * the default method, then just call RAND_bytes(). Otherwise make
325 * sure we're instantiated and use the private DRBG.
327 int RAND_priv_bytes(unsigned char *buf
, int num
)
329 const RAND_METHOD
*meth
= RAND_get_rand_method();
332 if (meth
!= RAND_OpenSSL())
333 return RAND_bytes(buf
, num
);
335 drbg
= RAND_DRBG_get0_priv_global();
339 return RAND_DRBG_generate(drbg
, buf
, num
, 0, NULL
, 0);
342 int RAND_bytes(unsigned char *buf
, int num
)
344 const RAND_METHOD
*meth
= RAND_get_rand_method();
346 if (meth
->bytes
!= NULL
)
347 return meth
->bytes(buf
, num
);
348 RANDerr(RAND_F_RAND_BYTES
, RAND_R_FUNC_NOT_IMPLEMENTED
);
352 #if OPENSSL_API_COMPAT < 0x10100000L
353 int RAND_pseudo_bytes(unsigned char *buf
, int num
)
355 const RAND_METHOD
*meth
= RAND_get_rand_method();
357 if (meth
->pseudorand
!= NULL
)
358 return meth
->pseudorand(buf
, num
);
363 int RAND_status(void)
365 const RAND_METHOD
*meth
= RAND_get_rand_method();
367 if (meth
->status
!= NULL
)
368 return meth
->status();