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 <openssl/async.h>
134 #include "rand_lcl.h"
136 #include <openssl/err.h>
139 # include <openssl/fips.h>
146 /* #define PREDICT 1 */
148 #define STATE_SIZE 1023
149 static int state_num = 0, state_index = 0;
150 static unsigned char state[STATE_SIZE + MD_DIGEST_LENGTH];
151 static unsigned char md[MD_DIGEST_LENGTH];
152 static long md_count[2] = { 0, 0 };
154 static double entropy = 0;
155 static int initialized = 0;
157 static unsigned int crypto_lock_rand = 0; /* may be set only when a thread
158 * holds CRYPTO_LOCK_RAND (to
159 * prevent double locking) */
160 /* access to lockin_thread is synchronized by CRYPTO_LOCK_RAND2 */
161 /* valid iff crypto_lock_rand is set */
162 static CRYPTO_THREADID locking_threadid;
165 int rand_predictable = 0;
168 static void rand_hw_seed(EVP_MD_CTX *ctx);
170 static void rand_cleanup(void);
171 static int rand_seed(const void *buf, int num);
172 static int rand_add(const void *buf, int num, double add_entropy);
173 static int rand_bytes(unsigned char *buf, int num, int pseudo);
174 static int rand_nopseudo_bytes(unsigned char *buf, int num);
175 #ifndef OPENSSL_NO_DEPRECATED
176 static int rand_pseudo_bytes(unsigned char *buf, int num);
178 static int rand_status(void);
180 static RAND_METHOD rand_meth = {
185 #ifndef OPENSSL_NO_DEPRECATED
193 RAND_METHOD *RAND_OpenSSL(void)
198 static void rand_cleanup(void)
200 OPENSSL_cleanse(state, sizeof(state));
203 OPENSSL_cleanse(md, MD_DIGEST_LENGTH);
210 static int rand_add(const void *buf, int num, double add)
214 unsigned char local_md[MD_DIGEST_LENGTH];
223 * (Based on the rand(3) manpage)
225 * The input is chopped up into units of 20 bytes (or less for
226 * the last block). Each of these blocks is run through the hash
227 * function as follows: The data passed to the hash function
228 * is the current 'md', the same number of bytes from the 'state'
229 * (the location determined by in incremented looping index) as
230 * the current 'block', the new key data 'block', and 'count'
231 * (which is incremented after each use).
232 * The result of this is kept in 'md' and also xored into the
233 * 'state' at the same locations that were used as input into the
237 m = EVP_MD_CTX_new();
241 /* check if we already have the lock */
242 if (crypto_lock_rand) {
244 CRYPTO_THREADID_current(&cur);
245 CRYPTO_r_lock(CRYPTO_LOCK_RAND2);
246 do_not_lock = !CRYPTO_THREADID_cmp(&locking_threadid, &cur);
247 CRYPTO_r_unlock(CRYPTO_LOCK_RAND2);
252 CRYPTO_w_lock(CRYPTO_LOCK_RAND);
253 st_idx = state_index;
256 * use our own copies of the counters so that even if a concurrent thread
257 * seeds with exactly the same data and uses the same subarray there's
260 md_c[0] = md_count[0];
261 md_c[1] = md_count[1];
263 memcpy(local_md, md, sizeof md);
265 /* state_index <= state_num <= STATE_SIZE */
267 if (state_index >= STATE_SIZE) {
268 state_index %= STATE_SIZE;
269 state_num = STATE_SIZE;
270 } else if (state_num < STATE_SIZE) {
271 if (state_index > state_num)
272 state_num = state_index;
274 /* state_index <= state_num <= STATE_SIZE */
277 * state[st_idx], ..., state[(st_idx + num - 1) % STATE_SIZE] are what we
278 * will use now, but other threads may use them as well
281 md_count[1] += (num / MD_DIGEST_LENGTH) + (num % MD_DIGEST_LENGTH > 0);
284 CRYPTO_w_unlock(CRYPTO_LOCK_RAND);
286 for (i = 0; i < num; i += MD_DIGEST_LENGTH) {
288 j = (j > MD_DIGEST_LENGTH) ? MD_DIGEST_LENGTH : j;
292 if (!MD_Update(m, local_md, MD_DIGEST_LENGTH))
294 k = (st_idx + j) - STATE_SIZE;
296 if (!MD_Update(m, &(state[st_idx]), j - k))
298 if (!MD_Update(m, &(state[0]), k))
300 } else if (!MD_Update(m, &(state[st_idx]), j))
303 /* DO NOT REMOVE THE FOLLOWING CALL TO MD_Update()! */
304 if (!MD_Update(m, buf, j))
307 * We know that line may cause programs such as purify and valgrind
308 * to complain about use of uninitialized data. The problem is not,
309 * it's with the caller. Removing that line will make sure you get
310 * really bad randomness and thereby other problems such as very
314 if (!MD_Update(m, (unsigned char *)&(md_c[0]), sizeof(md_c)))
316 if (!MD_Final(m, local_md))
320 buf = (const char *)buf + j;
322 for (k = 0; k < j; k++) {
324 * Parallel threads may interfere with this, but always each byte
325 * of the new state is the XOR of some previous value of its and
326 * local_md (itermediate values may be lost). Alway using locking
327 * could hurt performance more than necessary given that
328 * conflicts occur only when the total seeding is longer than the
331 state[st_idx++] ^= local_md[k];
332 if (st_idx >= STATE_SIZE)
338 CRYPTO_w_lock(CRYPTO_LOCK_RAND);
340 * Don't just copy back local_md into md -- this could mean that other
341 * thread's seeding remains without effect (except for the incremented
342 * counter). By XORing it we keep at least as much entropy as fits into
345 for (k = 0; k < (int)sizeof(md); k++) {
346 md[k] ^= local_md[k];
348 if (entropy < ENTROPY_NEEDED) /* stop counting when we have enough */
351 CRYPTO_w_unlock(CRYPTO_LOCK_RAND);
353 #if !defined(OPENSSL_THREADS) && !defined(OPENSSL_SYS_WIN32)
354 assert(md_c[1] == md_count[1]);
362 static int rand_seed(const void *buf, int num)
364 return rand_add(buf, num, (double)num);
367 static int rand_bytes(unsigned char *buf, int num, int pseudo)
369 static volatile int stirred_pool = 0;
370 int i, j, k, st_num, st_idx;
374 unsigned char local_md[MD_DIGEST_LENGTH];
376 #ifndef GETPID_IS_MEANINGLESS
377 pid_t curr_pid = getpid();
379 time_t curr_time = time(NULL);
380 int do_stir_pool = 0;
381 /* time value for various platforms */
382 #ifdef OPENSSL_SYS_WIN32
387 SystemTimeToFileTime(&t, &tv);
389 GetSystemTimeAsFileTime(&tv);
391 #elif defined(OPENSSL_SYS_VXWORKS)
393 clock_gettime(CLOCK_REALTIME, &ts);
394 #elif defined(OPENSSL_SYS_DSPBIOS)
395 unsigned long long tv, OPENSSL_rdtsc();
396 tv = OPENSSL_rdtsc();
399 gettimeofday(&tv, NULL);
403 if (rand_predictable) {
404 static unsigned char val = 0;
406 for (i = 0; i < num; i++)
415 m = EVP_MD_CTX_new();
419 /* round upwards to multiple of MD_DIGEST_LENGTH/2 */
421 (1 + (num - 1) / (MD_DIGEST_LENGTH / 2)) * (MD_DIGEST_LENGTH / 2);
424 * (Based on the rand(3) manpage:)
426 * For each group of 10 bytes (or less), we do the following:
428 * Input into the hash function the local 'md' (which is initialized from
429 * the global 'md' before any bytes are generated), the bytes that are to
430 * be overwritten by the random bytes, and bytes from the 'state'
431 * (incrementing looping index). From this digest output (which is kept
432 * in 'md'), the top (up to) 10 bytes are returned to the caller and the
433 * bottom 10 bytes are xored into the 'state'.
435 * Finally, after we have finished 'num' random bytes for the
436 * caller, 'count' (which is incremented) and the local and global 'md'
437 * are fed into the hash function and the results are kept in the
441 CRYPTO_w_lock(CRYPTO_LOCK_RAND);
443 * We could end up in an async engine while holding this lock so ensure
444 * we don't pause and cause a deadlock
448 /* prevent rand_bytes() from trying to obtain the lock again */
449 CRYPTO_w_lock(CRYPTO_LOCK_RAND2);
450 CRYPTO_THREADID_current(&locking_threadid);
451 CRYPTO_w_unlock(CRYPTO_LOCK_RAND2);
452 crypto_lock_rand = 1;
462 ok = (entropy >= ENTROPY_NEEDED);
465 * If the PRNG state is not yet unpredictable, then seeing the PRNG
466 * output may help attackers to determine the new state; thus we have
467 * to decrease the entropy estimate. Once we've had enough initial
468 * seeding we don't bother to adjust the entropy count, though,
469 * because we're not ambitious to provide *information-theoretic*
470 * randomness. NOTE: This approach fails if the program forks before
471 * we have enough entropy. Entropy should be collected in a separate
472 * input pool and be transferred to the output pool only when the
473 * entropy limit has been reached.
482 * In the output function only half of 'md' remains secret, so we
483 * better make sure that the required entropy gets 'evenly
484 * distributed' through 'state', our randomness pool. The input
485 * function (rand_add) chains all of 'md', which makes it more
486 * suitable for this purpose.
489 int n = STATE_SIZE; /* so that the complete pool gets accessed */
491 #if MD_DIGEST_LENGTH > 20
492 # error "Please adjust DUMMY_SEED."
494 #define DUMMY_SEED "...................." /* at least MD_DIGEST_LENGTH */
496 * Note that the seed does not matter, it's just that
497 * rand_add expects to have something to hash.
499 rand_add(DUMMY_SEED, MD_DIGEST_LENGTH, 0.0);
500 n -= MD_DIGEST_LENGTH;
506 st_idx = state_index;
508 md_c[0] = md_count[0];
509 md_c[1] = md_count[1];
510 memcpy(local_md, md, sizeof md);
512 state_index += num_ceil;
513 if (state_index > state_num)
514 state_index %= state_num;
517 * state[st_idx], ..., state[(st_idx + num_ceil - 1) % st_num] are now
518 * ours (but other threads may use them too)
523 /* before unlocking, we must clear 'crypto_lock_rand' */
524 crypto_lock_rand = 0;
525 ASYNC_unblock_pause();
526 CRYPTO_w_unlock(CRYPTO_LOCK_RAND);
529 /* num_ceil -= MD_DIGEST_LENGTH/2 */
530 j = (num >= MD_DIGEST_LENGTH / 2) ? MD_DIGEST_LENGTH / 2 : num;
534 #ifndef GETPID_IS_MEANINGLESS
535 if (curr_pid) { /* just in the first iteration to save time */
536 if (!MD_Update(m, (unsigned char *)&curr_pid, sizeof curr_pid))
541 if (curr_time) { /* just in the first iteration to save time */
542 if (!MD_Update(m, (unsigned char *)&curr_time, sizeof curr_time))
544 if (!MD_Update(m, (unsigned char *)&tv, sizeof tv))
549 if (!MD_Update(m, local_md, MD_DIGEST_LENGTH))
551 if (!MD_Update(m, (unsigned char *)&(md_c[0]), sizeof(md_c)))
554 #ifndef PURIFY /* purify complains */
556 * The following line uses the supplied buffer as a small source of
557 * entropy: since this buffer is often uninitialised it may cause
558 * programs such as purify or valgrind to complain. So for those
559 * builds it is not used: the removal of such a small source of
560 * entropy has negligible impact on security.
562 if (!MD_Update(m, buf, j))
566 k = (st_idx + MD_DIGEST_LENGTH / 2) - st_num;
568 if (!MD_Update(m, &(state[st_idx]), MD_DIGEST_LENGTH / 2 - k))
570 if (!MD_Update(m, &(state[0]), k))
572 } else if (!MD_Update(m, &(state[st_idx]), MD_DIGEST_LENGTH / 2))
574 if (!MD_Final(m, local_md))
577 for (i = 0; i < MD_DIGEST_LENGTH / 2; i++) {
578 /* may compete with other threads */
579 state[st_idx++] ^= local_md[i];
580 if (st_idx >= st_num)
583 *(buf++) = local_md[i + MD_DIGEST_LENGTH / 2];
588 || !MD_Update(m, (unsigned char *)&(md_c[0]), sizeof(md_c))
589 || !MD_Update(m, local_md, MD_DIGEST_LENGTH))
591 CRYPTO_w_lock(CRYPTO_LOCK_RAND);
593 * Prevent deadlocks if we end up in an async engine
596 if (!MD_Update(m, md, MD_DIGEST_LENGTH) || !MD_Final(m, md)) {
597 CRYPTO_w_unlock(CRYPTO_LOCK_RAND);
600 ASYNC_unblock_pause();
601 CRYPTO_w_unlock(CRYPTO_LOCK_RAND);
609 RANDerr(RAND_F_RAND_BYTES, RAND_R_PRNG_NOT_SEEDED);
610 ERR_add_error_data(1, "You need to read the OpenSSL FAQ, "
611 "http://www.openssl.org/support/faq.html");
615 RANDerr(RAND_F_RAND_BYTES, ERR_R_EVP_LIB);
619 RANDerr(RAND_F_RAND_BYTES, ERR_R_MALLOC_FAILURE);
625 static int rand_nopseudo_bytes(unsigned char *buf, int num)
627 return rand_bytes(buf, num, 0);
630 #ifndef OPENSSL_NO_DEPRECATED
632 * pseudo-random bytes that are guaranteed to be unique but not unpredictable
634 static int rand_pseudo_bytes(unsigned char *buf, int num)
636 return rand_bytes(buf, num, 1);
640 static int rand_status(void)
646 CRYPTO_THREADID_current(&cur);
648 * check if we already have the lock (could happen if a RAND_poll()
649 * implementation calls RAND_status())
651 if (crypto_lock_rand) {
652 CRYPTO_r_lock(CRYPTO_LOCK_RAND2);
653 do_not_lock = !CRYPTO_THREADID_cmp(&locking_threadid, &cur);
654 CRYPTO_r_unlock(CRYPTO_LOCK_RAND2);
659 CRYPTO_w_lock(CRYPTO_LOCK_RAND);
661 * Prevent deadlocks in case we end up in an async engine
666 * prevent rand_bytes() from trying to obtain the lock again
668 CRYPTO_w_lock(CRYPTO_LOCK_RAND2);
669 CRYPTO_THREADID_cpy(&locking_threadid, &cur);
670 CRYPTO_w_unlock(CRYPTO_LOCK_RAND2);
671 crypto_lock_rand = 1;
679 ret = entropy >= ENTROPY_NEEDED;
682 /* before unlocking, we must clear 'crypto_lock_rand' */
683 crypto_lock_rand = 0;
685 ASYNC_unblock_pause();
686 CRYPTO_w_unlock(CRYPTO_LOCK_RAND);
693 * rand_hw_seed: get seed data from any available hardware RNG. only
694 * currently supports rdrand.
697 /* Adapted from eng_rdrand.c */
699 #if (defined(__i386) || defined(__i386__) || defined(_M_IX86) || \
700 defined(__x86_64) || defined(__x86_64__) || \
701 defined(_M_AMD64) || defined (_M_X64)) && defined(OPENSSL_CPUID_OBJ)
703 # define RDRAND_CALLS 4
705 size_t OPENSSL_ia32_rdrand(void);
706 extern unsigned int OPENSSL_ia32cap_P[];
708 static void rand_hw_seed(EVP_MD_CTX *ctx)
711 if (!(OPENSSL_ia32cap_P[1] & (1 << (62 - 32))))
713 for (i = 0; i < RDRAND_CALLS; i++) {
715 rnd = OPENSSL_ia32_rdrand();
718 MD_Update(ctx, (unsigned char *)&rnd, sizeof(size_t));
722 /* XOR an existing buffer with random data */
724 void rand_hw_xor(unsigned char *buf, size_t num)
727 if (!(OPENSSL_ia32cap_P[1] & (1 << (62 - 32))))
729 while (num >= sizeof(size_t)) {
730 rnd = OPENSSL_ia32_rdrand();
733 *((size_t *)buf) ^= rnd;
734 buf += sizeof(size_t);
735 num -= sizeof(size_t);
738 rnd = OPENSSL_ia32_rdrand();
752 static void rand_hw_seed(EVP_MD_CTX *ctx)
757 void rand_hw_xor(unsigned char *buf, size_t num)