1 /* crypto/rand/md_rand.c */
2 /* Copyright (C) 1995-1998 Eric Young (eay@cryptsoft.com)
5 * This package is an SSL implementation written
6 * by Eric Young (eay@cryptsoft.com).
7 * The implementation was written so as to conform with Netscapes SSL.
9 * This library is free for commercial and non-commercial use as long as
10 * the following conditions are aheared to. The following conditions
11 * apply to all code found in this distribution, be it the RC4, RSA,
12 * lhash, DES, etc., code; not just the SSL code. The SSL documentation
13 * included with this distribution is covered by the same copyright terms
14 * except that the holder is Tim Hudson (tjh@cryptsoft.com).
16 * Copyright remains Eric Young's, and as such any Copyright notices in
17 * the code are not to be removed.
18 * If this package is used in a product, Eric Young should be given attribution
19 * as the author of the parts of the library used.
20 * This can be in the form of a textual message at program startup or
21 * in documentation (online or textual) provided with the package.
23 * Redistribution and use in source and binary forms, with or without
24 * modification, are permitted provided that the following conditions
26 * 1. Redistributions of source code must retain the copyright
27 * notice, this list of conditions and the following disclaimer.
28 * 2. Redistributions in binary form must reproduce the above copyright
29 * notice, this list of conditions and the following disclaimer in the
30 * documentation and/or other materials provided with the distribution.
31 * 3. All advertising materials mentioning features or use of this software
32 * must display the following acknowledgement:
33 * "This product includes cryptographic software written by
34 * Eric Young (eay@cryptsoft.com)"
35 * The word 'cryptographic' can be left out if the rouines from the library
36 * being used are not cryptographic related :-).
37 * 4. If you include any Windows specific code (or a derivative thereof) from
38 * the apps directory (application code) you must include an acknowledgement:
39 * "This product includes software written by Tim Hudson (tjh@cryptsoft.com)"
41 * THIS SOFTWARE IS PROVIDED BY ERIC YOUNG ``AS IS'' AND
42 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
43 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
44 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
45 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
46 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
47 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
48 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
49 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
50 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
53 * The licence and distribution terms for any publically available version or
54 * derivative of this code cannot be changed. i.e. this code cannot simply be
55 * copied and put under another distribution licence
56 * [including the GNU Public Licence.]
58 /* ====================================================================
59 * Copyright (c) 1998-2001 The OpenSSL Project. All rights reserved.
61 * Redistribution and use in source and binary forms, with or without
62 * modification, are permitted provided that the following conditions
65 * 1. Redistributions of source code must retain the above copyright
66 * notice, this list of conditions and the following disclaimer.
68 * 2. Redistributions in binary form must reproduce the above copyright
69 * notice, this list of conditions and the following disclaimer in
70 * the documentation and/or other materials provided with the
73 * 3. All advertising materials mentioning features or use of this
74 * software must display the following acknowledgment:
75 * "This product includes software developed by the OpenSSL Project
76 * for use in the OpenSSL Toolkit. (http://www.openssl.org/)"
78 * 4. The names "OpenSSL Toolkit" and "OpenSSL Project" must not be used to
79 * endorse or promote products derived from this software without
80 * prior written permission. For written permission, please contact
81 * openssl-core@openssl.org.
83 * 5. Products derived from this software may not be called "OpenSSL"
84 * nor may "OpenSSL" appear in their names without prior written
85 * permission of the OpenSSL Project.
87 * 6. Redistributions of any form whatsoever must retain the following
89 * "This product includes software developed by the OpenSSL Project
90 * for use in the OpenSSL Toolkit (http://www.openssl.org/)"
92 * THIS SOFTWARE IS PROVIDED BY THE OpenSSL PROJECT ``AS IS'' AND ANY
93 * EXPRESSED OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
94 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
95 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE OpenSSL PROJECT OR
96 * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
97 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
98 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
99 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
100 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
101 * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
102 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
103 * OF THE POSSIBILITY OF SUCH DAMAGE.
104 * ====================================================================
106 * This product includes cryptographic software written by Eric Young
107 * (eay@cryptsoft.com). This product includes software written by Tim
108 * Hudson (tjh@cryptsoft.com).
124 #if !(defined(OPENSSL_SYS_WIN32) || defined(OPENSSL_SYS_VXWORKS) || defined(OPENSSL_SYS_DSPBIOS))
125 # include <sys/time.h>
127 #if defined(OPENSSL_SYS_VXWORKS)
131 #include <openssl/crypto.h>
132 #include <openssl/rand.h>
133 #include "rand_lcl.h"
135 #include <openssl/err.h>
138 # include <openssl/fips.h>
145 /* #define PREDICT 1 */
147 #define STATE_SIZE 1023
148 static int state_num = 0, state_index = 0;
149 static unsigned char state[STATE_SIZE + MD_DIGEST_LENGTH];
150 static unsigned char md[MD_DIGEST_LENGTH];
151 static long md_count[2] = { 0, 0 };
153 static double entropy = 0;
154 static int initialized = 0;
156 static unsigned int crypto_lock_rand = 0; /* may be set only when a thread
157 * holds CRYPTO_LOCK_RAND (to
158 * prevent double locking) */
159 /* access to lockin_thread is synchronized by CRYPTO_LOCK_RAND2 */
160 /* valid iff crypto_lock_rand is set */
161 static CRYPTO_THREADID locking_threadid;
164 int rand_predictable = 0;
167 static void rand_hw_seed(EVP_MD_CTX *ctx);
169 static void rand_cleanup(void);
170 static int rand_seed(const void *buf, int num);
171 static int rand_add(const void *buf, int num, double add_entropy);
172 static int rand_bytes(unsigned char *buf, int num, int pseudo);
173 static int rand_nopseudo_bytes(unsigned char *buf, int num);
174 #ifndef OPENSSL_NO_DEPRECATED
175 static int rand_pseudo_bytes(unsigned char *buf, int num);
177 static int rand_status(void);
179 static RAND_METHOD rand_meth = {
184 #ifndef OPENSSL_NO_DEPRECATED
192 RAND_METHOD *RAND_OpenSSL(void)
197 static void rand_cleanup(void)
199 OPENSSL_cleanse(state, sizeof(state));
202 OPENSSL_cleanse(md, MD_DIGEST_LENGTH);
209 static int rand_add(const void *buf, int num, double add)
213 unsigned char local_md[MD_DIGEST_LENGTH];
222 * (Based on the rand(3) manpage)
224 * The input is chopped up into units of 20 bytes (or less for
225 * the last block). Each of these blocks is run through the hash
226 * function as follows: The data passed to the hash function
227 * is the current 'md', the same number of bytes from the 'state'
228 * (the location determined by in incremented looping index) as
229 * the current 'block', the new key data 'block', and 'count'
230 * (which is incremented after each use).
231 * The result of this is kept in 'md' and also xored into the
232 * 'state' at the same locations that were used as input into the
237 /* check if we already have the lock */
238 if (crypto_lock_rand) {
240 CRYPTO_THREADID_current(&cur);
241 CRYPTO_r_lock(CRYPTO_LOCK_RAND2);
242 do_not_lock = !CRYPTO_THREADID_cmp(&locking_threadid, &cur);
243 CRYPTO_r_unlock(CRYPTO_LOCK_RAND2);
248 CRYPTO_w_lock(CRYPTO_LOCK_RAND);
249 st_idx = state_index;
252 * use our own copies of the counters so that even if a concurrent thread
253 * seeds with exactly the same data and uses the same subarray there's
256 md_c[0] = md_count[0];
257 md_c[1] = md_count[1];
259 memcpy(local_md, md, sizeof md);
261 /* state_index <= state_num <= STATE_SIZE */
263 if (state_index >= STATE_SIZE) {
264 state_index %= STATE_SIZE;
265 state_num = STATE_SIZE;
266 } else if (state_num < STATE_SIZE) {
267 if (state_index > state_num)
268 state_num = state_index;
270 /* state_index <= state_num <= STATE_SIZE */
273 * state[st_idx], ..., state[(st_idx + num - 1) % STATE_SIZE] are what we
274 * will use now, but other threads may use them as well
277 md_count[1] += (num / MD_DIGEST_LENGTH) + (num % MD_DIGEST_LENGTH > 0);
280 CRYPTO_w_unlock(CRYPTO_LOCK_RAND);
282 for (i = 0; i < num; i += MD_DIGEST_LENGTH) {
284 j = (j > MD_DIGEST_LENGTH) ? MD_DIGEST_LENGTH : j;
288 if (!MD_Update(&m, local_md, MD_DIGEST_LENGTH))
290 k = (st_idx + j) - STATE_SIZE;
292 if (!MD_Update(&m, &(state[st_idx]), j - k))
294 if (!MD_Update(&m, &(state[0]), k))
296 } else if (!MD_Update(&m, &(state[st_idx]), j))
299 /* DO NOT REMOVE THE FOLLOWING CALL TO MD_Update()! */
300 if (!MD_Update(&m, buf, j))
303 * We know that line may cause programs such as purify and valgrind
304 * to complain about use of uninitialized data. The problem is not,
305 * it's with the caller. Removing that line will make sure you get
306 * really bad randomness and thereby other problems such as very
310 if (!MD_Update(&m, (unsigned char *)&(md_c[0]), sizeof(md_c)))
312 if (!MD_Final(&m, local_md))
316 buf = (const char *)buf + j;
318 for (k = 0; k < j; k++) {
320 * Parallel threads may interfere with this, but always each byte
321 * of the new state is the XOR of some previous value of its and
322 * local_md (itermediate values may be lost). Alway using locking
323 * could hurt performance more than necessary given that
324 * conflicts occur only when the total seeding is longer than the
327 state[st_idx++] ^= local_md[k];
328 if (st_idx >= STATE_SIZE)
334 CRYPTO_w_lock(CRYPTO_LOCK_RAND);
336 * Don't just copy back local_md into md -- this could mean that other
337 * thread's seeding remains without effect (except for the incremented
338 * counter). By XORing it we keep at least as much entropy as fits into
341 for (k = 0; k < (int)sizeof(md); k++) {
342 md[k] ^= local_md[k];
344 if (entropy < ENTROPY_NEEDED) /* stop counting when we have enough */
347 CRYPTO_w_unlock(CRYPTO_LOCK_RAND);
349 #if !defined(OPENSSL_THREADS) && !defined(OPENSSL_SYS_WIN32)
350 assert(md_c[1] == md_count[1]);
354 EVP_MD_CTX_cleanup(&m);
358 static int rand_seed(const void *buf, int num)
360 return rand_add(buf, num, (double)num);
363 static int rand_bytes(unsigned char *buf, int num, int pseudo)
365 static volatile int stirred_pool = 0;
366 int i, j, k, st_num, st_idx;
370 unsigned char local_md[MD_DIGEST_LENGTH];
372 #ifndef GETPID_IS_MEANINGLESS
373 pid_t curr_pid = getpid();
375 time_t curr_time = time(NULL);
376 int do_stir_pool = 0;
377 /* time value for various platforms */
378 #ifdef OPENSSL_SYS_WIN32
383 SystemTimeToFileTime(&t, &tv);
385 GetSystemTimeAsFileTime(&tv);
387 #elif defined(OPENSSL_SYS_VXWORKS)
389 clock_gettime(CLOCK_REALTIME, &ts);
390 #elif defined(OPENSSL_SYS_DSPBIOS)
391 unsigned long long tv, OPENSSL_rdtsc();
392 tv = OPENSSL_rdtsc();
395 gettimeofday(&tv, NULL);
399 if (rand_predictable) {
400 static unsigned char val = 0;
402 for (i = 0; i < num; i++)
412 /* round upwards to multiple of MD_DIGEST_LENGTH/2 */
414 (1 + (num - 1) / (MD_DIGEST_LENGTH / 2)) * (MD_DIGEST_LENGTH / 2);
417 * (Based on the rand(3) manpage:)
419 * For each group of 10 bytes (or less), we do the following:
421 * Input into the hash function the local 'md' (which is initialized from
422 * the global 'md' before any bytes are generated), the bytes that are to
423 * be overwritten by the random bytes, and bytes from the 'state'
424 * (incrementing looping index). From this digest output (which is kept
425 * in 'md'), the top (up to) 10 bytes are returned to the caller and the
426 * bottom 10 bytes are xored into the 'state'.
428 * Finally, after we have finished 'num' random bytes for the
429 * caller, 'count' (which is incremented) and the local and global 'md'
430 * are fed into the hash function and the results are kept in the
434 CRYPTO_w_lock(CRYPTO_LOCK_RAND);
436 /* prevent rand_bytes() from trying to obtain the lock again */
437 CRYPTO_w_lock(CRYPTO_LOCK_RAND2);
438 CRYPTO_THREADID_current(&locking_threadid);
439 CRYPTO_w_unlock(CRYPTO_LOCK_RAND2);
440 crypto_lock_rand = 1;
450 ok = (entropy >= ENTROPY_NEEDED);
453 * If the PRNG state is not yet unpredictable, then seeing the PRNG
454 * output may help attackers to determine the new state; thus we have
455 * to decrease the entropy estimate. Once we've had enough initial
456 * seeding we don't bother to adjust the entropy count, though,
457 * because we're not ambitious to provide *information-theoretic*
458 * randomness. NOTE: This approach fails if the program forks before
459 * we have enough entropy. Entropy should be collected in a separate
460 * input pool and be transferred to the output pool only when the
461 * entropy limit has been reached.
470 * In the output function only half of 'md' remains secret, so we
471 * better make sure that the required entropy gets 'evenly
472 * distributed' through 'state', our randomness pool. The input
473 * function (rand_add) chains all of 'md', which makes it more
474 * suitable for this purpose.
477 int n = STATE_SIZE; /* so that the complete pool gets accessed */
479 #if MD_DIGEST_LENGTH > 20
480 # error "Please adjust DUMMY_SEED."
482 #define DUMMY_SEED "...................." /* at least MD_DIGEST_LENGTH */
484 * Note that the seed does not matter, it's just that
485 * rand_add expects to have something to hash.
487 rand_add(DUMMY_SEED, MD_DIGEST_LENGTH, 0.0);
488 n -= MD_DIGEST_LENGTH;
494 st_idx = state_index;
496 md_c[0] = md_count[0];
497 md_c[1] = md_count[1];
498 memcpy(local_md, md, sizeof md);
500 state_index += num_ceil;
501 if (state_index > state_num)
502 state_index %= state_num;
505 * state[st_idx], ..., state[(st_idx + num_ceil - 1) % st_num] are now
506 * ours (but other threads may use them too)
511 /* before unlocking, we must clear 'crypto_lock_rand' */
512 crypto_lock_rand = 0;
513 CRYPTO_w_unlock(CRYPTO_LOCK_RAND);
516 /* num_ceil -= MD_DIGEST_LENGTH/2 */
517 j = (num >= MD_DIGEST_LENGTH / 2) ? MD_DIGEST_LENGTH / 2 : num;
521 #ifndef GETPID_IS_MEANINGLESS
522 if (curr_pid) { /* just in the first iteration to save time */
523 if (!MD_Update(&m, (unsigned char *)&curr_pid, sizeof curr_pid))
528 if (curr_time) { /* just in the first iteration to save time */
529 if (!MD_Update(&m, (unsigned char *)&curr_time, sizeof curr_time))
531 if (!MD_Update(&m, (unsigned char *)&tv, sizeof tv))
536 if (!MD_Update(&m, local_md, MD_DIGEST_LENGTH))
538 if (!MD_Update(&m, (unsigned char *)&(md_c[0]), sizeof(md_c)))
541 #ifndef PURIFY /* purify complains */
543 * The following line uses the supplied buffer as a small source of
544 * entropy: since this buffer is often uninitialised it may cause
545 * programs such as purify or valgrind to complain. So for those
546 * builds it is not used: the removal of such a small source of
547 * entropy has negligible impact on security.
549 if (!MD_Update(&m, buf, j))
553 k = (st_idx + MD_DIGEST_LENGTH / 2) - st_num;
555 if (!MD_Update(&m, &(state[st_idx]), MD_DIGEST_LENGTH / 2 - k))
557 if (!MD_Update(&m, &(state[0]), k))
559 } else if (!MD_Update(&m, &(state[st_idx]), MD_DIGEST_LENGTH / 2))
561 if (!MD_Final(&m, local_md))
564 for (i = 0; i < MD_DIGEST_LENGTH / 2; i++) {
565 /* may compete with other threads */
566 state[st_idx++] ^= local_md[i];
567 if (st_idx >= st_num)
570 *(buf++) = local_md[i + MD_DIGEST_LENGTH / 2];
575 || !MD_Update(&m, (unsigned char *)&(md_c[0]), sizeof(md_c))
576 || !MD_Update(&m, local_md, MD_DIGEST_LENGTH))
578 CRYPTO_w_lock(CRYPTO_LOCK_RAND);
579 if (!MD_Update(&m, md, MD_DIGEST_LENGTH) || !MD_Final(&m, md)) {
580 CRYPTO_w_unlock(CRYPTO_LOCK_RAND);
583 CRYPTO_w_unlock(CRYPTO_LOCK_RAND);
585 EVP_MD_CTX_cleanup(&m);
591 RANDerr(RAND_F_RAND_BYTES, RAND_R_PRNG_NOT_SEEDED);
592 ERR_add_error_data(1, "You need to read the OpenSSL FAQ, "
593 "http://www.openssl.org/support/faq.html");
597 EVP_MD_CTX_cleanup(&m);
598 RANDerr(RAND_F_RAND_BYTES, ERR_R_EVP_LIB);
603 static int rand_nopseudo_bytes(unsigned char *buf, int num)
605 return rand_bytes(buf, num, 0);
608 #ifndef OPENSSL_NO_DEPRECATED
610 * pseudo-random bytes that are guaranteed to be unique but not unpredictable
612 static int rand_pseudo_bytes(unsigned char *buf, int num)
614 return rand_bytes(buf, num, 1);
618 static int rand_status(void)
624 CRYPTO_THREADID_current(&cur);
626 * check if we already have the lock (could happen if a RAND_poll()
627 * implementation calls RAND_status())
629 if (crypto_lock_rand) {
630 CRYPTO_r_lock(CRYPTO_LOCK_RAND2);
631 do_not_lock = !CRYPTO_THREADID_cmp(&locking_threadid, &cur);
632 CRYPTO_r_unlock(CRYPTO_LOCK_RAND2);
637 CRYPTO_w_lock(CRYPTO_LOCK_RAND);
640 * prevent rand_bytes() from trying to obtain the lock again
642 CRYPTO_w_lock(CRYPTO_LOCK_RAND2);
643 CRYPTO_THREADID_cpy(&locking_threadid, &cur);
644 CRYPTO_w_unlock(CRYPTO_LOCK_RAND2);
645 crypto_lock_rand = 1;
653 ret = entropy >= ENTROPY_NEEDED;
656 /* before unlocking, we must clear 'crypto_lock_rand' */
657 crypto_lock_rand = 0;
659 CRYPTO_w_unlock(CRYPTO_LOCK_RAND);
666 * rand_hw_seed: get seed data from any available hardware RNG. only
667 * currently supports rdrand.
670 /* Adapted from eng_rdrand.c */
672 #if (defined(__i386) || defined(__i386__) || defined(_M_IX86) || \
673 defined(__x86_64) || defined(__x86_64__) || \
674 defined(_M_AMD64) || defined (_M_X64)) && defined(OPENSSL_CPUID_OBJ)
676 # define RDRAND_CALLS 4
678 size_t OPENSSL_ia32_rdrand(void);
679 extern unsigned int OPENSSL_ia32cap_P[];
681 static void rand_hw_seed(EVP_MD_CTX *ctx)
684 if (!(OPENSSL_ia32cap_P[1] & (1 << (62 - 32))))
686 for (i = 0; i < RDRAND_CALLS; i++) {
688 rnd = OPENSSL_ia32_rdrand();
691 MD_Update(ctx, (unsigned char *)&rnd, sizeof(size_t));
695 /* XOR an existing buffer with random data */
697 void rand_hw_xor(unsigned char *buf, size_t num)
700 if (!(OPENSSL_ia32cap_P[1] & (1 << (62 - 32))))
702 while (num >= sizeof(size_t)) {
703 rnd = OPENSSL_ia32_rdrand();
706 *((size_t *)buf) ^= rnd;
707 buf += sizeof(size_t);
708 num -= sizeof(size_t);
711 rnd = OPENSSL_ia32_rdrand();
725 static void rand_hw_seed(EVP_MD_CTX *ctx)
730 void rand_hw_xor(unsigned char *buf, size_t num)