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).
112 #define OPENSSL_FIPSAPI
126 #if !(defined(OPENSSL_SYS_WIN32) || defined(OPENSSL_SYS_VXWORKS) || defined(OPENSSL_SYSNAME_DSPBIOS))
127 # include <sys/time.h>
129 #if defined(OPENSSL_SYS_VXWORKS)
133 #include <openssl/crypto.h>
134 #include <openssl/rand.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};
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
159 * (to prevent double locking) */
160 /* access to lockin_thread is synchronized by CRYPTO_LOCK_RAND2 */
161 static CRYPTO_THREADID locking_threadid; /* valid iff crypto_lock_rand is set */
165 int rand_predictable=0;
168 const char RAND_version[]="RAND" OPENSSL_VERSION_PTEXT;
170 static void ssleay_rand_cleanup(void);
171 static int ssleay_rand_seed(const void *buf, int num);
172 static int ssleay_rand_add(const void *buf, int num, double add_entropy);
173 static int ssleay_rand_bytes(unsigned char *buf, int num, int pseudo);
174 static int ssleay_rand_nopseudo_bytes(unsigned char *buf, int num);
175 static int ssleay_rand_pseudo_bytes(unsigned char *buf, int num);
176 static int ssleay_rand_status(void);
178 static RAND_METHOD rand_ssleay_meth={
180 ssleay_rand_nopseudo_bytes,
183 ssleay_rand_pseudo_bytes,
187 RAND_METHOD *RAND_SSLeay(void)
189 return(&rand_ssleay_meth);
192 static void ssleay_rand_cleanup(void)
194 OPENSSL_cleanse(state,sizeof(state));
197 OPENSSL_cleanse(md,MD_DIGEST_LENGTH);
204 static int ssleay_rand_add(const void *buf, int num, double add)
208 unsigned char local_md[MD_DIGEST_LENGTH];
214 * (Based on the rand(3) manpage)
216 * The input is chopped up into units of 20 bytes (or less for
217 * the last block). Each of these blocks is run through the hash
218 * function as follows: The data passed to the hash function
219 * is the current 'md', the same number of bytes from the 'state'
220 * (the location determined by in incremented looping index) as
221 * the current 'block', the new key data 'block', and 'count'
222 * (which is incremented after each use).
223 * The result of this is kept in 'md' and also xored into the
224 * 'state' at the same locations that were used as input into the
229 /* check if we already have the lock */
230 if (crypto_lock_rand)
233 CRYPTO_THREADID_current(&cur);
234 CRYPTO_r_lock(CRYPTO_LOCK_RAND2);
235 do_not_lock = !CRYPTO_THREADID_cmp(&locking_threadid, &cur);
236 CRYPTO_r_unlock(CRYPTO_LOCK_RAND2);
241 if (!do_not_lock) CRYPTO_w_lock(CRYPTO_LOCK_RAND);
244 /* use our own copies of the counters so that even
245 * if a concurrent thread seeds with exactly the
246 * same data and uses the same subarray there's _some_
248 md_c[0] = md_count[0];
249 md_c[1] = md_count[1];
251 memcpy(local_md, md, sizeof md);
253 /* state_index <= state_num <= STATE_SIZE */
255 if (state_index >= STATE_SIZE)
257 state_index%=STATE_SIZE;
258 state_num=STATE_SIZE;
260 else if (state_num < STATE_SIZE)
262 if (state_index > state_num)
263 state_num=state_index;
265 /* state_index <= state_num <= STATE_SIZE */
267 /* state[st_idx], ..., state[(st_idx + num - 1) % STATE_SIZE]
268 * are what we will use now, but other threads may use them
271 md_count[1] += (num / MD_DIGEST_LENGTH) + (num % MD_DIGEST_LENGTH > 0);
273 if (!do_not_lock) CRYPTO_w_unlock(CRYPTO_LOCK_RAND);
275 for (i=0; i<num; i+=MD_DIGEST_LENGTH)
278 j=(j > MD_DIGEST_LENGTH)?MD_DIGEST_LENGTH:j;
282 if (!MD_Update(&m,local_md,MD_DIGEST_LENGTH))
284 k=(st_idx+j)-STATE_SIZE;
287 if (!MD_Update(&m,&(state[st_idx]),j-k))
289 if (!MD_Update(&m,&(state[0]),k))
293 if (!MD_Update(&m,&(state[st_idx]),j))
296 /* DO NOT REMOVE THE FOLLOWING CALL TO MD_Update()! */
297 if (!MD_Update(&m,buf,j))
299 /* We know that line may cause programs such as
300 purify and valgrind to complain about use of
301 uninitialized data. The problem is not, it's
302 with the caller. Removing that line will make
303 sure you get really bad randomness and thereby
304 other problems such as very insecure keys. */
306 if (!MD_Update(&m,(unsigned char *)&(md_c[0]),sizeof(md_c)))
308 if (!MD_Final(&m,local_md))
312 buf=(const char *)buf + j;
316 /* Parallel threads may interfere with this,
317 * but always each byte of the new state is
318 * the XOR of some previous value of its
319 * and local_md (itermediate values may be lost).
320 * Alway using locking could hurt performance more
321 * than necessary given that conflicts occur only
322 * when the total seeding is longer than the random
324 state[st_idx++]^=local_md[k];
325 if (st_idx >= STATE_SIZE)
330 if (!do_not_lock) CRYPTO_w_lock(CRYPTO_LOCK_RAND);
331 /* Don't just copy back local_md into md -- this could mean that
332 * other thread's seeding remains without effect (except for
333 * the incremented counter). By XORing it we keep at least as
334 * much entropy as fits into md. */
335 for (k = 0; k < (int)sizeof(md); k++)
337 md[k] ^= local_md[k];
339 if (entropy < ENTROPY_NEEDED) /* stop counting when we have enough */
341 if (!do_not_lock) CRYPTO_w_unlock(CRYPTO_LOCK_RAND);
343 #if !defined(OPENSSL_THREADS) && !defined(OPENSSL_SYS_WIN32)
344 assert(md_c[1] == md_count[1]);
348 EVP_MD_CTX_cleanup(&m);
352 static int ssleay_rand_seed(const void *buf, int num)
354 return ssleay_rand_add(buf, num, (double)num);
357 static int ssleay_rand_bytes(unsigned char *buf, int num, int pseudo)
359 static volatile int stirred_pool = 0;
360 int i,j,k,st_num,st_idx;
364 unsigned char local_md[MD_DIGEST_LENGTH];
366 #ifndef GETPID_IS_MEANINGLESS
367 pid_t curr_pid = getpid();
369 time_t curr_time = time(NULL);
370 int do_stir_pool = 0;
371 /* time value for various platforms */
372 #ifdef OPENSSL_SYS_WIN32
377 SystemTimeToFileTime(&t, &tv);
379 GetSystemTimeAsFileTime(&tv);
381 #elif defined(OPENSSL_SYS_VXWORKS)
383 clock_gettime(CLOCK_REALTIME, &ts);
384 #elif defined(OPENSSL_SYSNAME_DSPBIOS)
385 unsigned long long tv, OPENSSL_rdtsc();
386 tv = OPENSSL_rdtsc();
389 gettimeofday(&tv, NULL);
393 if (rand_predictable)
395 static unsigned char val=0;
397 for (i=0; i<num; i++)
407 /* round upwards to multiple of MD_DIGEST_LENGTH/2 */
408 num_ceil = (1 + (num-1)/(MD_DIGEST_LENGTH/2)) * (MD_DIGEST_LENGTH/2);
411 * (Based on the rand(3) manpage:)
413 * For each group of 10 bytes (or less), we do the following:
415 * Input into the hash function the local 'md' (which is initialized from
416 * the global 'md' before any bytes are generated), the bytes that are to
417 * be overwritten by the random bytes, and bytes from the 'state'
418 * (incrementing looping index). From this digest output (which is kept
419 * in 'md'), the top (up to) 10 bytes are returned to the caller and the
420 * bottom 10 bytes are xored into the 'state'.
422 * Finally, after we have finished 'num' random bytes for the
423 * caller, 'count' (which is incremented) and the local and global 'md'
424 * are fed into the hash function and the results are kept in the
428 CRYPTO_w_lock(CRYPTO_LOCK_RAND);
430 /* prevent ssleay_rand_bytes() from trying to obtain the lock again */
431 CRYPTO_w_lock(CRYPTO_LOCK_RAND2);
432 CRYPTO_THREADID_current(&locking_threadid);
433 CRYPTO_w_unlock(CRYPTO_LOCK_RAND2);
434 crypto_lock_rand = 1;
445 ok = (entropy >= ENTROPY_NEEDED);
448 /* If the PRNG state is not yet unpredictable, then seeing
449 * the PRNG output may help attackers to determine the new
450 * state; thus we have to decrease the entropy estimate.
451 * Once we've had enough initial seeding we don't bother to
452 * adjust the entropy count, though, because we're not ambitious
453 * to provide *information-theoretic* randomness.
455 * NOTE: This approach fails if the program forks before
456 * we have enough entropy. Entropy should be collected
457 * in a separate input pool and be transferred to the
458 * output pool only when the entropy limit has been reached.
467 /* In the output function only half of 'md' remains secret,
468 * so we better make sure that the required entropy gets
469 * 'evenly distributed' through 'state', our randomness pool.
470 * The input function (ssleay_rand_add) chains all of 'md',
471 * which makes it more suitable for this purpose.
474 int n = STATE_SIZE; /* so that the complete pool gets accessed */
477 #if MD_DIGEST_LENGTH > 20
478 # error "Please adjust DUMMY_SEED."
480 #define DUMMY_SEED "...................." /* at least MD_DIGEST_LENGTH */
481 /* Note that the seed does not matter, it's just that
482 * ssleay_rand_add expects to have something to hash. */
483 ssleay_rand_add(DUMMY_SEED, MD_DIGEST_LENGTH, 0.0);
484 n -= MD_DIGEST_LENGTH;
492 md_c[0] = md_count[0];
493 md_c[1] = md_count[1];
494 memcpy(local_md, md, sizeof md);
496 state_index+=num_ceil;
497 if (state_index > state_num)
498 state_index %= state_num;
500 /* state[st_idx], ..., state[(st_idx + num_ceil - 1) % st_num]
501 * are now ours (but other threads may use them too) */
505 /* before unlocking, we must clear 'crypto_lock_rand' */
506 crypto_lock_rand = 0;
507 CRYPTO_w_unlock(CRYPTO_LOCK_RAND);
511 /* num_ceil -= MD_DIGEST_LENGTH/2 */
512 j=(num >= MD_DIGEST_LENGTH/2)?MD_DIGEST_LENGTH/2:num;
516 #ifndef GETPID_IS_MEANINGLESS
517 if (curr_pid) /* just in the first iteration to save time */
519 if (!MD_Update(&m,(unsigned char*)&curr_pid,
525 if (curr_time) /* just in the first iteration to save time */
527 if (!MD_Update(&m,(unsigned char*)&curr_time,
530 if (!MD_Update(&m,(unsigned char*)&tv,
535 if (!MD_Update(&m,local_md,MD_DIGEST_LENGTH))
537 if (!MD_Update(&m,(unsigned char *)&(md_c[0]),sizeof(md_c)))
540 #ifndef PURIFY /* purify complains */
541 /* The following line uses the supplied buffer as a small
542 * source of entropy: since this buffer is often uninitialised
543 * it may cause programs such as purify or valgrind to
544 * complain. So for those builds it is not used: the removal
545 * of such a small source of entropy has negligible impact on
548 if (!MD_Update(&m,buf,j))
552 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))
561 if (!MD_Update(&m,&(state[st_idx]),MD_DIGEST_LENGTH/2))
563 if (!MD_Final(&m,local_md))
566 for (i=0; i<MD_DIGEST_LENGTH/2; i++)
568 state[st_idx++]^=local_md[i]; /* may compete with other threads */
569 if (st_idx >= st_num)
572 *(buf++)=local_md[i+MD_DIGEST_LENGTH/2];
577 || !MD_Update(&m,(unsigned char *)&(md_c[0]),sizeof(md_c))
578 || !MD_Update(&m,local_md,MD_DIGEST_LENGTH))
580 CRYPTO_w_lock(CRYPTO_LOCK_RAND);
581 if (!MD_Update(&m,md,MD_DIGEST_LENGTH) || !MD_Final(&m,md))
583 CRYPTO_w_unlock(CRYPTO_LOCK_RAND);
586 CRYPTO_w_unlock(CRYPTO_LOCK_RAND);
588 EVP_MD_CTX_cleanup(&m);
595 RANDerr(RAND_F_SSLEAY_RAND_BYTES,RAND_R_PRNG_NOT_SEEDED);
596 ERR_add_error_data(1, "You need to read the OpenSSL FAQ, "
597 "http://www.openssl.org/support/faq.html");
601 EVP_MD_CTX_cleanup(&m);
602 RANDerr(RAND_F_SSLEAY_RAND_BYTES,ERR_R_EVP_LIB);
607 static int ssleay_rand_nopseudo_bytes(unsigned char *buf, int num)
609 return ssleay_rand_bytes(buf, num, 0);
612 /* pseudo-random bytes that are guaranteed to be unique but not
614 static int ssleay_rand_pseudo_bytes(unsigned char *buf, int num)
616 return ssleay_rand_bytes(buf, num, 1);
619 static int ssleay_rand_status(void)
625 CRYPTO_THREADID_current(&cur);
626 /* check if we already have the lock
627 * (could happen if a RAND_poll() implementation calls RAND_status()) */
628 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);
639 CRYPTO_w_lock(CRYPTO_LOCK_RAND);
641 /* prevent ssleay_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;
654 ret = entropy >= ENTROPY_NEEDED;
658 /* before unlocking, we must clear 'crypto_lock_rand' */
659 crypto_lock_rand = 0;
661 CRYPTO_w_unlock(CRYPTO_LOCK_RAND);