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 #include <openssl/crypto.h>
127 #include <openssl/rand.h>
128 #include "rand_lcl.h"
130 #include <openssl/err.h>
133 #include <openssl/fips.h>
140 /* #define PREDICT 1 */
142 #define STATE_SIZE 1023
143 static int state_num=0,state_index=0;
144 static unsigned char state[STATE_SIZE+MD_DIGEST_LENGTH];
145 static unsigned char md[MD_DIGEST_LENGTH];
146 static long md_count[2]={0,0};
147 static double entropy=0;
148 static int initialized=0;
150 static unsigned int crypto_lock_rand = 0; /* may be set only when a thread
151 * holds CRYPTO_LOCK_RAND
152 * (to prevent double locking) */
153 /* access to lockin_thread is synchronized by CRYPTO_LOCK_RAND2 */
154 static CRYPTO_THREADID locking_threadid; /* valid iff crypto_lock_rand is set */
158 int rand_predictable=0;
161 const char RAND_version[]="RAND" OPENSSL_VERSION_PTEXT;
163 static void ssleay_rand_cleanup(void);
164 static int ssleay_rand_seed(const void *buf, int num);
165 static int ssleay_rand_add(const void *buf, int num, double add_entropy);
166 static int ssleay_rand_bytes(unsigned char *buf, int num, int pseudo);
167 static int ssleay_rand_nopseudo_bytes(unsigned char *buf, int num);
168 static int ssleay_rand_pseudo_bytes(unsigned char *buf, int num);
169 static int ssleay_rand_status(void);
171 static RAND_METHOD rand_ssleay_meth={
173 ssleay_rand_nopseudo_bytes,
176 ssleay_rand_pseudo_bytes,
180 RAND_METHOD *RAND_SSLeay(void)
182 return(&rand_ssleay_meth);
185 static void ssleay_rand_cleanup(void)
187 OPENSSL_cleanse(state,sizeof(state));
190 OPENSSL_cleanse(md,MD_DIGEST_LENGTH);
197 static int ssleay_rand_add(const void *buf, int num, double add)
201 unsigned char local_md[MD_DIGEST_LENGTH];
207 * (Based on the rand(3) manpage)
209 * The input is chopped up into units of 20 bytes (or less for
210 * the last block). Each of these blocks is run through the hash
211 * function as follows: The data passed to the hash function
212 * is the current 'md', the same number of bytes from the 'state'
213 * (the location determined by in incremented looping index) as
214 * the current 'block', the new key data 'block', and 'count'
215 * (which is incremented after each use).
216 * The result of this is kept in 'md' and also xored into the
217 * 'state' at the same locations that were used as input into the
222 /* check if we already have the lock */
223 if (crypto_lock_rand)
226 CRYPTO_THREADID_current(&cur);
227 CRYPTO_r_lock(CRYPTO_LOCK_RAND2);
228 do_not_lock = !CRYPTO_THREADID_cmp(&locking_threadid, &cur);
229 CRYPTO_r_unlock(CRYPTO_LOCK_RAND2);
234 if (!do_not_lock) CRYPTO_w_lock(CRYPTO_LOCK_RAND);
237 /* use our own copies of the counters so that even
238 * if a concurrent thread seeds with exactly the
239 * same data and uses the same subarray there's _some_
241 md_c[0] = md_count[0];
242 md_c[1] = md_count[1];
244 memcpy(local_md, md, sizeof md);
246 /* state_index <= state_num <= STATE_SIZE */
248 if (state_index >= STATE_SIZE)
250 state_index%=STATE_SIZE;
251 state_num=STATE_SIZE;
253 else if (state_num < STATE_SIZE)
255 if (state_index > state_num)
256 state_num=state_index;
258 /* state_index <= state_num <= STATE_SIZE */
260 /* state[st_idx], ..., state[(st_idx + num - 1) % STATE_SIZE]
261 * are what we will use now, but other threads may use them
264 md_count[1] += (num / MD_DIGEST_LENGTH) + (num % MD_DIGEST_LENGTH > 0);
266 if (!do_not_lock) CRYPTO_w_unlock(CRYPTO_LOCK_RAND);
268 for (i=0; i<num; i+=MD_DIGEST_LENGTH)
271 j=(j > MD_DIGEST_LENGTH)?MD_DIGEST_LENGTH:j;
275 if (!MD_Update(&m,local_md,MD_DIGEST_LENGTH))
277 k=(st_idx+j)-STATE_SIZE;
280 if (!MD_Update(&m,&(state[st_idx]),j-k))
282 if (!MD_Update(&m,&(state[0]),k))
286 if (!MD_Update(&m,&(state[st_idx]),j))
289 /* DO NOT REMOVE THE FOLLOWING CALL TO MD_Update()! */
290 if (!MD_Update(&m,buf,j))
292 /* We know that line may cause programs such as
293 purify and valgrind to complain about use of
294 uninitialized data. The problem is not, it's
295 with the caller. Removing that line will make
296 sure you get really bad randomness and thereby
297 other problems such as very insecure keys. */
299 if (!MD_Update(&m,(unsigned char *)&(md_c[0]),sizeof(md_c)))
301 if (!MD_Final(&m,local_md))
305 buf=(const char *)buf + j;
309 /* Parallel threads may interfere with this,
310 * but always each byte of the new state is
311 * the XOR of some previous value of its
312 * and local_md (itermediate values may be lost).
313 * Alway using locking could hurt performance more
314 * than necessary given that conflicts occur only
315 * when the total seeding is longer than the random
317 state[st_idx++]^=local_md[k];
318 if (st_idx >= STATE_SIZE)
323 if (!do_not_lock) CRYPTO_w_lock(CRYPTO_LOCK_RAND);
324 /* Don't just copy back local_md into md -- this could mean that
325 * other thread's seeding remains without effect (except for
326 * the incremented counter). By XORing it we keep at least as
327 * much entropy as fits into md. */
328 for (k = 0; k < (int)sizeof(md); k++)
330 md[k] ^= local_md[k];
332 if (entropy < ENTROPY_NEEDED) /* stop counting when we have enough */
334 if (!do_not_lock) CRYPTO_w_unlock(CRYPTO_LOCK_RAND);
336 #if !defined(OPENSSL_THREADS) && !defined(OPENSSL_SYS_WIN32)
337 assert(md_c[1] == md_count[1]);
341 EVP_MD_CTX_cleanup(&m);
345 static int ssleay_rand_seed(const void *buf, int num)
347 return ssleay_rand_add(buf, num, (double)num);
350 static int ssleay_rand_bytes(unsigned char *buf, int num, int pseudo)
352 static volatile int stirred_pool = 0;
353 int i,j,k,st_num,st_idx;
357 unsigned char local_md[MD_DIGEST_LENGTH];
359 #ifndef GETPID_IS_MEANINGLESS
360 pid_t curr_pid = getpid();
362 int do_stir_pool = 0;
365 if (rand_predictable)
367 static unsigned char val=0;
369 for (i=0; i<num; i++)
379 /* round upwards to multiple of MD_DIGEST_LENGTH/2 */
380 num_ceil = (1 + (num-1)/(MD_DIGEST_LENGTH/2)) * (MD_DIGEST_LENGTH/2);
383 * (Based on the rand(3) manpage:)
385 * For each group of 10 bytes (or less), we do the following:
387 * Input into the hash function the local 'md' (which is initialized from
388 * the global 'md' before any bytes are generated), the bytes that are to
389 * be overwritten by the random bytes, and bytes from the 'state'
390 * (incrementing looping index). From this digest output (which is kept
391 * in 'md'), the top (up to) 10 bytes are returned to the caller and the
392 * bottom 10 bytes are xored into the 'state'.
394 * Finally, after we have finished 'num' random bytes for the
395 * caller, 'count' (which is incremented) and the local and global 'md'
396 * are fed into the hash function and the results are kept in the
400 CRYPTO_w_lock(CRYPTO_LOCK_RAND);
402 /* prevent ssleay_rand_bytes() from trying to obtain the lock again */
403 CRYPTO_w_lock(CRYPTO_LOCK_RAND2);
404 CRYPTO_THREADID_current(&locking_threadid);
405 CRYPTO_w_unlock(CRYPTO_LOCK_RAND2);
406 crypto_lock_rand = 1;
417 ok = (entropy >= ENTROPY_NEEDED);
420 /* If the PRNG state is not yet unpredictable, then seeing
421 * the PRNG output may help attackers to determine the new
422 * state; thus we have to decrease the entropy estimate.
423 * Once we've had enough initial seeding we don't bother to
424 * adjust the entropy count, though, because we're not ambitious
425 * to provide *information-theoretic* randomness.
427 * NOTE: This approach fails if the program forks before
428 * we have enough entropy. Entropy should be collected
429 * in a separate input pool and be transferred to the
430 * output pool only when the entropy limit has been reached.
439 /* In the output function only half of 'md' remains secret,
440 * so we better make sure that the required entropy gets
441 * 'evenly distributed' through 'state', our randomness pool.
442 * The input function (ssleay_rand_add) chains all of 'md',
443 * which makes it more suitable for this purpose.
446 int n = STATE_SIZE; /* so that the complete pool gets accessed */
449 #if MD_DIGEST_LENGTH > 20
450 # error "Please adjust DUMMY_SEED."
452 #define DUMMY_SEED "...................." /* at least MD_DIGEST_LENGTH */
453 /* Note that the seed does not matter, it's just that
454 * ssleay_rand_add expects to have something to hash. */
455 ssleay_rand_add(DUMMY_SEED, MD_DIGEST_LENGTH, 0.0);
456 n -= MD_DIGEST_LENGTH;
464 md_c[0] = md_count[0];
465 md_c[1] = md_count[1];
466 memcpy(local_md, md, sizeof md);
468 state_index+=num_ceil;
469 if (state_index > state_num)
470 state_index %= state_num;
472 /* state[st_idx], ..., state[(st_idx + num_ceil - 1) % st_num]
473 * are now ours (but other threads may use them too) */
477 /* before unlocking, we must clear 'crypto_lock_rand' */
478 crypto_lock_rand = 0;
479 CRYPTO_w_unlock(CRYPTO_LOCK_RAND);
483 /* num_ceil -= MD_DIGEST_LENGTH/2 */
484 j=(num >= MD_DIGEST_LENGTH/2)?MD_DIGEST_LENGTH/2:num;
488 #ifndef GETPID_IS_MEANINGLESS
489 if (curr_pid) /* just in the first iteration to save time */
491 if (!MD_Update(&m,(unsigned char*)&curr_pid,sizeof curr_pid))
496 if (!MD_Update(&m,local_md,MD_DIGEST_LENGTH))
498 if (!MD_Update(&m,(unsigned char *)&(md_c[0]),sizeof(md_c)))
501 #ifndef PURIFY /* purify complains */
502 /* The following line uses the supplied buffer as a small
503 * source of entropy: since this buffer is often uninitialised
504 * it may cause programs such as purify or valgrind to
505 * complain. So for those builds it is not used: the removal
506 * of such a small source of entropy has negligible impact on
509 if (!MD_Update(&m,buf,j))
513 k=(st_idx+MD_DIGEST_LENGTH/2)-st_num;
516 if (!MD_Update(&m,&(state[st_idx]),MD_DIGEST_LENGTH/2-k))
518 if (!MD_Update(&m,&(state[0]),k))
522 if (!MD_Update(&m,&(state[st_idx]),MD_DIGEST_LENGTH/2))
524 if (!MD_Final(&m,local_md))
527 for (i=0; i<MD_DIGEST_LENGTH/2; i++)
529 state[st_idx++]^=local_md[i]; /* may compete with other threads */
530 if (st_idx >= st_num)
533 *(buf++)=local_md[i+MD_DIGEST_LENGTH/2];
538 || !MD_Update(&m,(unsigned char *)&(md_c[0]),sizeof(md_c))
539 || !MD_Update(&m,local_md,MD_DIGEST_LENGTH))
541 CRYPTO_w_lock(CRYPTO_LOCK_RAND);
542 if (!MD_Update(&m,md,MD_DIGEST_LENGTH) || !MD_Final(&m,md))
544 CRYPTO_w_unlock(CRYPTO_LOCK_RAND);
547 CRYPTO_w_unlock(CRYPTO_LOCK_RAND);
549 EVP_MD_CTX_cleanup(&m);
556 RANDerr(RAND_F_SSLEAY_RAND_BYTES,RAND_R_PRNG_NOT_SEEDED);
557 ERR_add_error_data(1, "You need to read the OpenSSL FAQ, "
558 "http://www.openssl.org/support/faq.html");
562 EVP_MD_CTX_cleanup(&m);
563 RANDerr(RAND_F_SSLEAY_RAND_BYTES,ERR_R_EVP_LIB);
568 static int ssleay_rand_nopseudo_bytes(unsigned char *buf, int num)
570 return ssleay_rand_bytes(buf, num, 0);
573 /* pseudo-random bytes that are guaranteed to be unique but not
575 static int ssleay_rand_pseudo_bytes(unsigned char *buf, int num)
577 return ssleay_rand_bytes(buf, num, 1);
580 static int ssleay_rand_status(void)
586 CRYPTO_THREADID_current(&cur);
587 /* check if we already have the lock
588 * (could happen if a RAND_poll() implementation calls RAND_status()) */
589 if (crypto_lock_rand)
591 CRYPTO_r_lock(CRYPTO_LOCK_RAND2);
592 do_not_lock = !CRYPTO_THREADID_cmp(&locking_threadid, &cur);
593 CRYPTO_r_unlock(CRYPTO_LOCK_RAND2);
600 CRYPTO_w_lock(CRYPTO_LOCK_RAND);
602 /* prevent ssleay_rand_bytes() from trying to obtain the lock again */
603 CRYPTO_w_lock(CRYPTO_LOCK_RAND2);
604 CRYPTO_THREADID_cpy(&locking_threadid, &cur);
605 CRYPTO_w_unlock(CRYPTO_LOCK_RAND2);
606 crypto_lock_rand = 1;
615 ret = entropy >= ENTROPY_NEEDED;
619 /* before unlocking, we must clear 'crypto_lock_rand' */
620 crypto_lock_rand = 0;
622 CRYPTO_w_unlock(CRYPTO_LOCK_RAND);