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
123 #include <sys/time.h>
127 #include <openssl/crypto.h>
128 #include <openssl/rand.h>
129 #include "rand_lcl.h"
131 #include <openssl/err.h>
134 #include <openssl/fips.h>
141 /* #define PREDICT 1 */
143 #define STATE_SIZE 1023
144 static int state_num=0,state_index=0;
145 static unsigned char state[STATE_SIZE+MD_DIGEST_LENGTH];
146 static unsigned char md[MD_DIGEST_LENGTH];
147 static long md_count[2]={0,0};
148 static double entropy=0;
149 static int initialized=0;
151 static unsigned int crypto_lock_rand = 0; /* may be set only when a thread
152 * holds CRYPTO_LOCK_RAND
153 * (to prevent double locking) */
154 /* access to lockin_thread is synchronized by CRYPTO_LOCK_RAND2 */
155 static CRYPTO_THREADID locking_threadid; /* valid iff crypto_lock_rand is set */
159 int rand_predictable=0;
162 const char RAND_version[]="RAND" OPENSSL_VERSION_PTEXT;
164 static void ssleay_rand_cleanup(void);
165 static int ssleay_rand_seed(const void *buf, int num);
166 static int ssleay_rand_add(const void *buf, int num, double add_entropy);
167 static int ssleay_rand_bytes(unsigned char *buf, int num, int pseudo);
168 static int ssleay_rand_nopseudo_bytes(unsigned char *buf, int num);
169 static int ssleay_rand_pseudo_bytes(unsigned char *buf, int num);
170 static int ssleay_rand_status(void);
172 static RAND_METHOD rand_ssleay_meth={
174 ssleay_rand_nopseudo_bytes,
177 ssleay_rand_pseudo_bytes,
181 RAND_METHOD *RAND_SSLeay(void)
183 return(&rand_ssleay_meth);
186 static void ssleay_rand_cleanup(void)
188 OPENSSL_cleanse(state,sizeof(state));
191 OPENSSL_cleanse(md,MD_DIGEST_LENGTH);
198 static int ssleay_rand_add(const void *buf, int num, double add)
202 unsigned char local_md[MD_DIGEST_LENGTH];
208 * (Based on the rand(3) manpage)
210 * The input is chopped up into units of 20 bytes (or less for
211 * the last block). Each of these blocks is run through the hash
212 * function as follows: The data passed to the hash function
213 * is the current 'md', the same number of bytes from the 'state'
214 * (the location determined by in incremented looping index) as
215 * the current 'block', the new key data 'block', and 'count'
216 * (which is incremented after each use).
217 * The result of this is kept in 'md' and also xored into the
218 * 'state' at the same locations that were used as input into the
223 /* check if we already have the lock */
224 if (crypto_lock_rand)
227 CRYPTO_THREADID_current(&cur);
228 CRYPTO_r_lock(CRYPTO_LOCK_RAND2);
229 do_not_lock = !CRYPTO_THREADID_cmp(&locking_threadid, &cur);
230 CRYPTO_r_unlock(CRYPTO_LOCK_RAND2);
235 if (!do_not_lock) CRYPTO_w_lock(CRYPTO_LOCK_RAND);
238 /* use our own copies of the counters so that even
239 * if a concurrent thread seeds with exactly the
240 * same data and uses the same subarray there's _some_
242 md_c[0] = md_count[0];
243 md_c[1] = md_count[1];
245 memcpy(local_md, md, sizeof md);
247 /* state_index <= state_num <= STATE_SIZE */
249 if (state_index >= STATE_SIZE)
251 state_index%=STATE_SIZE;
252 state_num=STATE_SIZE;
254 else if (state_num < STATE_SIZE)
256 if (state_index > state_num)
257 state_num=state_index;
259 /* state_index <= state_num <= STATE_SIZE */
261 /* state[st_idx], ..., state[(st_idx + num - 1) % STATE_SIZE]
262 * are what we will use now, but other threads may use them
265 md_count[1] += (num / MD_DIGEST_LENGTH) + (num % MD_DIGEST_LENGTH > 0);
267 if (!do_not_lock) CRYPTO_w_unlock(CRYPTO_LOCK_RAND);
269 for (i=0; i<num; i+=MD_DIGEST_LENGTH)
272 j=(j > MD_DIGEST_LENGTH)?MD_DIGEST_LENGTH:j;
276 if (!MD_Update(&m,local_md,MD_DIGEST_LENGTH))
278 k=(st_idx+j)-STATE_SIZE;
281 if (!MD_Update(&m,&(state[st_idx]),j-k))
283 if (!MD_Update(&m,&(state[0]),k))
287 if (!MD_Update(&m,&(state[st_idx]),j))
290 /* DO NOT REMOVE THE FOLLOWING CALL TO MD_Update()! */
291 if (!MD_Update(&m,buf,j))
293 /* We know that line may cause programs such as
294 purify and valgrind to complain about use of
295 uninitialized data. The problem is not, it's
296 with the caller. Removing that line will make
297 sure you get really bad randomness and thereby
298 other problems such as very insecure keys. */
300 if (!MD_Update(&m,(unsigned char *)&(md_c[0]),sizeof(md_c)))
302 if (!MD_Final(&m,local_md))
306 buf=(const char *)buf + j;
310 /* Parallel threads may interfere with this,
311 * but always each byte of the new state is
312 * the XOR of some previous value of its
313 * and local_md (itermediate values may be lost).
314 * Alway using locking could hurt performance more
315 * than necessary given that conflicts occur only
316 * when the total seeding is longer than the random
318 state[st_idx++]^=local_md[k];
319 if (st_idx >= STATE_SIZE)
324 if (!do_not_lock) CRYPTO_w_lock(CRYPTO_LOCK_RAND);
325 /* Don't just copy back local_md into md -- this could mean that
326 * other thread's seeding remains without effect (except for
327 * the incremented counter). By XORing it we keep at least as
328 * much entropy as fits into md. */
329 for (k = 0; k < (int)sizeof(md); k++)
331 md[k] ^= local_md[k];
333 if (entropy < ENTROPY_NEEDED) /* stop counting when we have enough */
335 if (!do_not_lock) CRYPTO_w_unlock(CRYPTO_LOCK_RAND);
337 #if !defined(OPENSSL_THREADS) && !defined(OPENSSL_SYS_WIN32)
338 assert(md_c[1] == md_count[1]);
342 EVP_MD_CTX_cleanup(&m);
346 static int ssleay_rand_seed(const void *buf, int num)
348 return ssleay_rand_add(buf, num, (double)num);
351 static int ssleay_rand_bytes(unsigned char *buf, int num, int pseudo)
353 static volatile int stirred_pool = 0;
354 int i,j,k,st_num,st_idx;
358 unsigned char local_md[MD_DIGEST_LENGTH];
360 #ifndef GETPID_IS_MEANINGLESS
361 pid_t curr_pid = getpid();
363 time_t curr_time = time(NULL);
365 int do_stir_pool = 0;
367 gettimeofday(&tv, NULL);
370 if (rand_predictable)
372 static unsigned char val=0;
374 for (i=0; i<num; i++)
384 /* round upwards to multiple of MD_DIGEST_LENGTH/2 */
385 num_ceil = (1 + (num-1)/(MD_DIGEST_LENGTH/2)) * (MD_DIGEST_LENGTH/2);
388 * (Based on the rand(3) manpage:)
390 * For each group of 10 bytes (or less), we do the following:
392 * Input into the hash function the local 'md' (which is initialized from
393 * the global 'md' before any bytes are generated), the bytes that are to
394 * be overwritten by the random bytes, and bytes from the 'state'
395 * (incrementing looping index). From this digest output (which is kept
396 * in 'md'), the top (up to) 10 bytes are returned to the caller and the
397 * bottom 10 bytes are xored into the 'state'.
399 * Finally, after we have finished 'num' random bytes for the
400 * caller, 'count' (which is incremented) and the local and global 'md'
401 * are fed into the hash function and the results are kept in the
405 CRYPTO_w_lock(CRYPTO_LOCK_RAND);
407 /* prevent ssleay_rand_bytes() from trying to obtain the lock again */
408 CRYPTO_w_lock(CRYPTO_LOCK_RAND2);
409 CRYPTO_THREADID_current(&locking_threadid);
410 CRYPTO_w_unlock(CRYPTO_LOCK_RAND2);
411 crypto_lock_rand = 1;
422 ok = (entropy >= ENTROPY_NEEDED);
425 /* If the PRNG state is not yet unpredictable, then seeing
426 * the PRNG output may help attackers to determine the new
427 * state; thus we have to decrease the entropy estimate.
428 * Once we've had enough initial seeding we don't bother to
429 * adjust the entropy count, though, because we're not ambitious
430 * to provide *information-theoretic* randomness.
432 * NOTE: This approach fails if the program forks before
433 * we have enough entropy. Entropy should be collected
434 * in a separate input pool and be transferred to the
435 * output pool only when the entropy limit has been reached.
444 /* In the output function only half of 'md' remains secret,
445 * so we better make sure that the required entropy gets
446 * 'evenly distributed' through 'state', our randomness pool.
447 * The input function (ssleay_rand_add) chains all of 'md',
448 * which makes it more suitable for this purpose.
451 int n = STATE_SIZE; /* so that the complete pool gets accessed */
454 #if MD_DIGEST_LENGTH > 20
455 # error "Please adjust DUMMY_SEED."
457 #define DUMMY_SEED "...................." /* at least MD_DIGEST_LENGTH */
458 /* Note that the seed does not matter, it's just that
459 * ssleay_rand_add expects to have something to hash. */
460 ssleay_rand_add(DUMMY_SEED, MD_DIGEST_LENGTH, 0.0);
461 n -= MD_DIGEST_LENGTH;
469 md_c[0] = md_count[0];
470 md_c[1] = md_count[1];
471 memcpy(local_md, md, sizeof md);
473 state_index+=num_ceil;
474 if (state_index > state_num)
475 state_index %= state_num;
477 /* state[st_idx], ..., state[(st_idx + num_ceil - 1) % st_num]
478 * are now ours (but other threads may use them too) */
482 /* before unlocking, we must clear 'crypto_lock_rand' */
483 crypto_lock_rand = 0;
484 CRYPTO_w_unlock(CRYPTO_LOCK_RAND);
488 /* num_ceil -= MD_DIGEST_LENGTH/2 */
489 j=(num >= MD_DIGEST_LENGTH/2)?MD_DIGEST_LENGTH/2:num;
493 #ifndef GETPID_IS_MEANINGLESS
494 if (curr_pid) /* just in the first iteration to save time */
496 if (!MD_Update(&m,(unsigned char*)&curr_pid,
502 if (curr_time) /* just in the first iteration to save time */
504 if (!MD_Update(&m,(unsigned char*)&curr_time,
509 if (tv.tv_sec) /* just in the first iteration to save time */
511 if (!MD_Update(&m,(unsigned char*)&tv,
516 if (!MD_Update(&m,local_md,MD_DIGEST_LENGTH))
518 if (!MD_Update(&m,(unsigned char *)&(md_c[0]),sizeof(md_c)))
521 #ifndef PURIFY /* purify complains */
522 /* The following line uses the supplied buffer as a small
523 * source of entropy: since this buffer is often uninitialised
524 * it may cause programs such as purify or valgrind to
525 * complain. So for those builds it is not used: the removal
526 * of such a small source of entropy has negligible impact on
529 if (!MD_Update(&m,buf,j))
533 k=(st_idx+MD_DIGEST_LENGTH/2)-st_num;
536 if (!MD_Update(&m,&(state[st_idx]),MD_DIGEST_LENGTH/2-k))
538 if (!MD_Update(&m,&(state[0]),k))
542 if (!MD_Update(&m,&(state[st_idx]),MD_DIGEST_LENGTH/2))
544 if (!MD_Final(&m,local_md))
547 for (i=0; i<MD_DIGEST_LENGTH/2; i++)
549 state[st_idx++]^=local_md[i]; /* may compete with other threads */
550 if (st_idx >= st_num)
553 *(buf++)=local_md[i+MD_DIGEST_LENGTH/2];
558 || !MD_Update(&m,(unsigned char *)&(md_c[0]),sizeof(md_c))
559 || !MD_Update(&m,local_md,MD_DIGEST_LENGTH))
561 CRYPTO_w_lock(CRYPTO_LOCK_RAND);
562 if (!MD_Update(&m,md,MD_DIGEST_LENGTH) || !MD_Final(&m,md))
564 CRYPTO_w_unlock(CRYPTO_LOCK_RAND);
567 CRYPTO_w_unlock(CRYPTO_LOCK_RAND);
569 EVP_MD_CTX_cleanup(&m);
576 RANDerr(RAND_F_SSLEAY_RAND_BYTES,RAND_R_PRNG_NOT_SEEDED);
577 ERR_add_error_data(1, "You need to read the OpenSSL FAQ, "
578 "http://www.openssl.org/support/faq.html");
582 EVP_MD_CTX_cleanup(&m);
583 RANDerr(RAND_F_SSLEAY_RAND_BYTES,ERR_R_EVP_LIB);
588 static int ssleay_rand_nopseudo_bytes(unsigned char *buf, int num)
590 return ssleay_rand_bytes(buf, num, 0);
593 /* pseudo-random bytes that are guaranteed to be unique but not
595 static int ssleay_rand_pseudo_bytes(unsigned char *buf, int num)
597 return ssleay_rand_bytes(buf, num, 1);
600 static int ssleay_rand_status(void)
606 CRYPTO_THREADID_current(&cur);
607 /* check if we already have the lock
608 * (could happen if a RAND_poll() implementation calls RAND_status()) */
609 if (crypto_lock_rand)
611 CRYPTO_r_lock(CRYPTO_LOCK_RAND2);
612 do_not_lock = !CRYPTO_THREADID_cmp(&locking_threadid, &cur);
613 CRYPTO_r_unlock(CRYPTO_LOCK_RAND2);
620 CRYPTO_w_lock(CRYPTO_LOCK_RAND);
622 /* prevent ssleay_rand_bytes() from trying to obtain the lock again */
623 CRYPTO_w_lock(CRYPTO_LOCK_RAND2);
624 CRYPTO_THREADID_cpy(&locking_threadid, &cur);
625 CRYPTO_w_unlock(CRYPTO_LOCK_RAND2);
626 crypto_lock_rand = 1;
635 ret = entropy >= ENTROPY_NEEDED;
639 /* before unlocking, we must clear 'crypto_lock_rand' */
640 crypto_lock_rand = 0;
642 CRYPTO_w_unlock(CRYPTO_LOCK_RAND);