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/opensslconf.h>
132 #include <openssl/crypto.h>
133 #include <openssl/rand.h>
134 #include <openssl/async.h>
135 #include "rand_lcl.h"
137 #include <openssl/err.h>
140 # include <openssl/fips.h>
147 /* #define PREDICT 1 */
149 #define STATE_SIZE 1023
150 static int state_num = 0, state_index = 0;
151 static unsigned char state[STATE_SIZE + MD_DIGEST_LENGTH];
152 static unsigned char md[MD_DIGEST_LENGTH];
153 static long md_count[2] = { 0, 0 };
155 static double entropy = 0;
156 static int initialized = 0;
158 static unsigned int crypto_lock_rand = 0; /* may be set only when a thread
159 * holds CRYPTO_LOCK_RAND (to
160 * prevent double locking) */
161 /* access to lockin_thread is synchronized by CRYPTO_LOCK_RAND2 */
162 /* valid iff crypto_lock_rand is set */
163 static CRYPTO_THREADID locking_threadid;
166 int rand_predictable = 0;
169 static void rand_hw_seed(EVP_MD_CTX *ctx);
171 static void rand_cleanup(void);
172 static int rand_seed(const void *buf, int num);
173 static int rand_add(const void *buf, int num, double add_entropy);
174 static int rand_bytes(unsigned char *buf, int num, int pseudo);
175 static int rand_nopseudo_bytes(unsigned char *buf, int num);
176 #if OPENSSL_API_COMPAT < 0x10100000L
177 static int rand_pseudo_bytes(unsigned char *buf, int num);
179 static int rand_status(void);
181 static RAND_METHOD rand_meth = {
186 #if OPENSSL_API_COMPAT < 0x10100000L
194 RAND_METHOD *RAND_OpenSSL(void)
199 static void rand_cleanup(void)
201 OPENSSL_cleanse(state, sizeof(state));
204 OPENSSL_cleanse(md, MD_DIGEST_LENGTH);
211 static int rand_add(const void *buf, int num, double add)
215 unsigned char local_md[MD_DIGEST_LENGTH];
224 * (Based on the rand(3) manpage)
226 * The input is chopped up into units of 20 bytes (or less for
227 * the last block). Each of these blocks is run through the hash
228 * function as follows: The data passed to the hash function
229 * is the current 'md', the same number of bytes from the 'state'
230 * (the location determined by in incremented looping index) as
231 * the current 'block', the new key data 'block', and 'count'
232 * (which is incremented after each use).
233 * The result of this is kept in 'md' and also xored into the
234 * 'state' at the same locations that were used as input into the
238 m = EVP_MD_CTX_new();
242 /* check if we already have the lock */
243 if (crypto_lock_rand) {
245 CRYPTO_THREADID_current(&cur);
246 CRYPTO_r_lock(CRYPTO_LOCK_RAND2);
247 do_not_lock = !CRYPTO_THREADID_cmp(&locking_threadid, &cur);
248 CRYPTO_r_unlock(CRYPTO_LOCK_RAND2);
253 CRYPTO_w_lock(CRYPTO_LOCK_RAND);
254 st_idx = state_index;
257 * use our own copies of the counters so that even if a concurrent thread
258 * seeds with exactly the same data and uses the same subarray there's
261 md_c[0] = md_count[0];
262 md_c[1] = md_count[1];
264 memcpy(local_md, md, sizeof md);
266 /* state_index <= state_num <= STATE_SIZE */
268 if (state_index >= STATE_SIZE) {
269 state_index %= STATE_SIZE;
270 state_num = STATE_SIZE;
271 } else if (state_num < STATE_SIZE) {
272 if (state_index > state_num)
273 state_num = state_index;
275 /* state_index <= state_num <= STATE_SIZE */
278 * state[st_idx], ..., state[(st_idx + num - 1) % STATE_SIZE] are what we
279 * will use now, but other threads may use them as well
282 md_count[1] += (num / MD_DIGEST_LENGTH) + (num % MD_DIGEST_LENGTH > 0);
285 CRYPTO_w_unlock(CRYPTO_LOCK_RAND);
287 for (i = 0; i < num; i += MD_DIGEST_LENGTH) {
289 j = (j > MD_DIGEST_LENGTH) ? MD_DIGEST_LENGTH : j;
293 if (!MD_Update(m, local_md, MD_DIGEST_LENGTH))
295 k = (st_idx + j) - STATE_SIZE;
297 if (!MD_Update(m, &(state[st_idx]), j - k))
299 if (!MD_Update(m, &(state[0]), k))
301 } else if (!MD_Update(m, &(state[st_idx]), j))
304 /* DO NOT REMOVE THE FOLLOWING CALL TO MD_Update()! */
305 if (!MD_Update(m, buf, j))
308 * We know that line may cause programs such as purify and valgrind
309 * to complain about use of uninitialized data. The problem is not,
310 * it's with the caller. Removing that line will make sure you get
311 * really bad randomness and thereby other problems such as very
315 if (!MD_Update(m, (unsigned char *)&(md_c[0]), sizeof(md_c)))
317 if (!MD_Final(m, local_md))
321 buf = (const char *)buf + j;
323 for (k = 0; k < j; k++) {
325 * Parallel threads may interfere with this, but always each byte
326 * of the new state is the XOR of some previous value of its and
327 * local_md (itermediate values may be lost). Alway using locking
328 * could hurt performance more than necessary given that
329 * conflicts occur only when the total seeding is longer than the
332 state[st_idx++] ^= local_md[k];
333 if (st_idx >= STATE_SIZE)
339 CRYPTO_w_lock(CRYPTO_LOCK_RAND);
341 * Don't just copy back local_md into md -- this could mean that other
342 * thread's seeding remains without effect (except for the incremented
343 * counter). By XORing it we keep at least as much entropy as fits into
346 for (k = 0; k < (int)sizeof(md); k++) {
347 md[k] ^= local_md[k];
349 if (entropy < ENTROPY_NEEDED) /* stop counting when we have enough */
352 CRYPTO_w_unlock(CRYPTO_LOCK_RAND);
354 #if !defined(OPENSSL_THREADS) && !defined(OPENSSL_SYS_WIN32)
355 assert(md_c[1] == md_count[1]);
363 static int rand_seed(const void *buf, int num)
365 return rand_add(buf, num, (double)num);
368 static int rand_bytes(unsigned char *buf, int num, int pseudo)
370 static volatile int stirred_pool = 0;
371 int i, j, k, st_num, st_idx;
375 unsigned char local_md[MD_DIGEST_LENGTH];
377 #ifndef GETPID_IS_MEANINGLESS
378 pid_t curr_pid = getpid();
380 time_t curr_time = time(NULL);
381 int do_stir_pool = 0;
382 /* time value for various platforms */
383 #ifdef OPENSSL_SYS_WIN32
388 SystemTimeToFileTime(&t, &tv);
390 GetSystemTimeAsFileTime(&tv);
392 #elif defined(OPENSSL_SYS_VXWORKS)
394 clock_gettime(CLOCK_REALTIME, &ts);
395 #elif defined(OPENSSL_SYS_DSPBIOS)
396 unsigned long long tv, OPENSSL_rdtsc();
397 tv = OPENSSL_rdtsc();
400 gettimeofday(&tv, NULL);
404 if (rand_predictable) {
405 static unsigned char val = 0;
407 for (i = 0; i < num; i++)
416 m = EVP_MD_CTX_new();
420 /* round upwards to multiple of MD_DIGEST_LENGTH/2 */
422 (1 + (num - 1) / (MD_DIGEST_LENGTH / 2)) * (MD_DIGEST_LENGTH / 2);
425 * (Based on the rand(3) manpage:)
427 * For each group of 10 bytes (or less), we do the following:
429 * Input into the hash function the local 'md' (which is initialized from
430 * the global 'md' before any bytes are generated), the bytes that are to
431 * be overwritten by the random bytes, and bytes from the 'state'
432 * (incrementing looping index). From this digest output (which is kept
433 * in 'md'), the top (up to) 10 bytes are returned to the caller and the
434 * bottom 10 bytes are xored into the 'state'.
436 * Finally, after we have finished 'num' random bytes for the
437 * caller, 'count' (which is incremented) and the local and global 'md'
438 * are fed into the hash function and the results are kept in the
442 CRYPTO_w_lock(CRYPTO_LOCK_RAND);
444 * We could end up in an async engine while holding this lock so ensure
445 * we don't pause and cause a deadlock
449 /* prevent rand_bytes() from trying to obtain the lock again */
450 CRYPTO_w_lock(CRYPTO_LOCK_RAND2);
451 CRYPTO_THREADID_current(&locking_threadid);
452 CRYPTO_w_unlock(CRYPTO_LOCK_RAND2);
453 crypto_lock_rand = 1;
463 ok = (entropy >= ENTROPY_NEEDED);
466 * If the PRNG state is not yet unpredictable, then seeing the PRNG
467 * output may help attackers to determine the new state; thus we have
468 * to decrease the entropy estimate. Once we've had enough initial
469 * seeding we don't bother to adjust the entropy count, though,
470 * because we're not ambitious to provide *information-theoretic*
471 * randomness. NOTE: This approach fails if the program forks before
472 * we have enough entropy. Entropy should be collected in a separate
473 * input pool and be transferred to the output pool only when the
474 * entropy limit has been reached.
483 * In the output function only half of 'md' remains secret, so we
484 * better make sure that the required entropy gets 'evenly
485 * distributed' through 'state', our randomness pool. The input
486 * function (rand_add) chains all of 'md', which makes it more
487 * suitable for this purpose.
490 int n = STATE_SIZE; /* so that the complete pool gets accessed */
492 #if MD_DIGEST_LENGTH > 20
493 # error "Please adjust DUMMY_SEED."
495 #define DUMMY_SEED "...................." /* at least MD_DIGEST_LENGTH */
497 * Note that the seed does not matter, it's just that
498 * rand_add expects to have something to hash.
500 rand_add(DUMMY_SEED, MD_DIGEST_LENGTH, 0.0);
501 n -= MD_DIGEST_LENGTH;
507 st_idx = state_index;
509 md_c[0] = md_count[0];
510 md_c[1] = md_count[1];
511 memcpy(local_md, md, sizeof md);
513 state_index += num_ceil;
514 if (state_index > state_num)
515 state_index %= state_num;
518 * state[st_idx], ..., state[(st_idx + num_ceil - 1) % st_num] are now
519 * ours (but other threads may use them too)
524 /* before unlocking, we must clear 'crypto_lock_rand' */
525 crypto_lock_rand = 0;
526 ASYNC_unblock_pause();
527 CRYPTO_w_unlock(CRYPTO_LOCK_RAND);
530 /* num_ceil -= MD_DIGEST_LENGTH/2 */
531 j = (num >= MD_DIGEST_LENGTH / 2) ? MD_DIGEST_LENGTH / 2 : num;
535 #ifndef GETPID_IS_MEANINGLESS
536 if (curr_pid) { /* just in the first iteration to save time */
537 if (!MD_Update(m, (unsigned char *)&curr_pid, sizeof curr_pid))
542 if (curr_time) { /* just in the first iteration to save time */
543 if (!MD_Update(m, (unsigned char *)&curr_time, sizeof curr_time))
545 if (!MD_Update(m, (unsigned char *)&tv, sizeof tv))
550 if (!MD_Update(m, local_md, MD_DIGEST_LENGTH))
552 if (!MD_Update(m, (unsigned char *)&(md_c[0]), sizeof(md_c)))
555 #ifndef PURIFY /* purify complains */
557 * The following line uses the supplied buffer as a small source of
558 * entropy: since this buffer is often uninitialised it may cause
559 * programs such as purify or valgrind to complain. So for those
560 * builds it is not used: the removal of such a small source of
561 * entropy has negligible impact on security.
563 if (!MD_Update(m, buf, j))
567 k = (st_idx + MD_DIGEST_LENGTH / 2) - st_num;
569 if (!MD_Update(m, &(state[st_idx]), MD_DIGEST_LENGTH / 2 - k))
571 if (!MD_Update(m, &(state[0]), k))
573 } else if (!MD_Update(m, &(state[st_idx]), MD_DIGEST_LENGTH / 2))
575 if (!MD_Final(m, local_md))
578 for (i = 0; i < MD_DIGEST_LENGTH / 2; i++) {
579 /* may compete with other threads */
580 state[st_idx++] ^= local_md[i];
581 if (st_idx >= st_num)
584 *(buf++) = local_md[i + MD_DIGEST_LENGTH / 2];
589 || !MD_Update(m, (unsigned char *)&(md_c[0]), sizeof(md_c))
590 || !MD_Update(m, local_md, MD_DIGEST_LENGTH))
592 CRYPTO_w_lock(CRYPTO_LOCK_RAND);
594 * Prevent deadlocks if we end up in an async engine
597 if (!MD_Update(m, md, MD_DIGEST_LENGTH) || !MD_Final(m, md)) {
598 CRYPTO_w_unlock(CRYPTO_LOCK_RAND);
601 ASYNC_unblock_pause();
602 CRYPTO_w_unlock(CRYPTO_LOCK_RAND);
610 RANDerr(RAND_F_RAND_BYTES, RAND_R_PRNG_NOT_SEEDED);
611 ERR_add_error_data(1, "You need to read the OpenSSL FAQ, "
612 "http://www.openssl.org/support/faq.html");
616 RANDerr(RAND_F_RAND_BYTES, ERR_R_EVP_LIB);
620 RANDerr(RAND_F_RAND_BYTES, ERR_R_MALLOC_FAILURE);
626 static int rand_nopseudo_bytes(unsigned char *buf, int num)
628 return rand_bytes(buf, num, 0);
631 #if OPENSSL_API_COMPAT < 0x10100000L
633 * pseudo-random bytes that are guaranteed to be unique but not unpredictable
635 static int rand_pseudo_bytes(unsigned char *buf, int num)
637 return rand_bytes(buf, num, 1);
641 static int rand_status(void)
647 CRYPTO_THREADID_current(&cur);
649 * check if we already have the lock (could happen if a RAND_poll()
650 * implementation calls RAND_status())
652 if (crypto_lock_rand) {
653 CRYPTO_r_lock(CRYPTO_LOCK_RAND2);
654 do_not_lock = !CRYPTO_THREADID_cmp(&locking_threadid, &cur);
655 CRYPTO_r_unlock(CRYPTO_LOCK_RAND2);
660 CRYPTO_w_lock(CRYPTO_LOCK_RAND);
662 * Prevent deadlocks in case we end up in an async engine
667 * prevent rand_bytes() from trying to obtain the lock again
669 CRYPTO_w_lock(CRYPTO_LOCK_RAND2);
670 CRYPTO_THREADID_cpy(&locking_threadid, &cur);
671 CRYPTO_w_unlock(CRYPTO_LOCK_RAND2);
672 crypto_lock_rand = 1;
680 ret = entropy >= ENTROPY_NEEDED;
683 /* before unlocking, we must clear 'crypto_lock_rand' */
684 crypto_lock_rand = 0;
686 ASYNC_unblock_pause();
687 CRYPTO_w_unlock(CRYPTO_LOCK_RAND);
694 * rand_hw_seed: get seed data from any available hardware RNG. only
695 * currently supports rdrand.
698 /* Adapted from eng_rdrand.c */
700 #if (defined(__i386) || defined(__i386__) || defined(_M_IX86) || \
701 defined(__x86_64) || defined(__x86_64__) || \
702 defined(_M_AMD64) || defined (_M_X64)) && defined(OPENSSL_CPUID_OBJ)
704 # define RDRAND_CALLS 4
706 size_t OPENSSL_ia32_rdrand(void);
707 extern unsigned int OPENSSL_ia32cap_P[];
709 static void rand_hw_seed(EVP_MD_CTX *ctx)
712 if (!(OPENSSL_ia32cap_P[1] & (1 << (62 - 32))))
714 for (i = 0; i < RDRAND_CALLS; i++) {
716 rnd = OPENSSL_ia32_rdrand();
719 MD_Update(ctx, (unsigned char *)&rnd, sizeof(size_t));
723 /* XOR an existing buffer with random data */
725 void rand_hw_xor(unsigned char *buf, size_t num)
728 if (!(OPENSSL_ia32cap_P[1] & (1 << (62 - 32))))
730 while (num >= sizeof(size_t)) {
731 rnd = OPENSSL_ia32_rdrand();
734 *((size_t *)buf) ^= rnd;
735 buf += sizeof(size_t);
736 num -= sizeof(size_t);
739 rnd = OPENSSL_ia32_rdrand();
753 static void rand_hw_seed(EVP_MD_CTX *ctx)
758 void rand_hw_xor(unsigned char *buf, size_t num)