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) 1998-2000 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 ENTROPY_NEEDED 20 /* require 160 bits = 20 bytes of randomness */
125 #include "openssl/e_os.h"
127 #include <openssl/crypto.h>
128 #include <openssl/err.h>
130 #if !defined(USE_MD5_RAND) && !defined(USE_SHA1_RAND) && !defined(USE_MDC2_RAND) && !defined(USE_MD2_RAND)
131 #if !defined(NO_SHA) && !defined(NO_SHA1)
132 #define USE_SHA1_RAND
133 #elif !defined(NO_MD5)
135 #elif !defined(NO_MDC2) && !defined(NO_DES)
136 #define USE_MDC2_RAND
137 #elif !defined(NO_MD2)
140 #error No message digest algorithm available
144 /* Changed how the state buffer used. I now attempt to 'wrap' such
145 * that I don't run over the same locations the next time go through
146 * the 1023 bytes - many thanks to
147 * Robert J. LeBlanc <rjl@renaissoft.com> for his comments
150 #if defined(USE_MD5_RAND)
151 #include <openssl/md5.h>
152 #define MD_DIGEST_LENGTH MD5_DIGEST_LENGTH
153 #define MD_CTX MD5_CTX
154 #define MD_Init(a) MD5_Init(a)
155 #define MD_Update(a,b,c) MD5_Update(a,b,c)
156 #define MD_Final(a,b) MD5_Final(a,b)
157 #define MD(a,b,c) MD5(a,b,c)
158 #elif defined(USE_SHA1_RAND)
159 #include <openssl/sha.h>
160 #define MD_DIGEST_LENGTH SHA_DIGEST_LENGTH
161 #define MD_CTX SHA_CTX
162 #define MD_Init(a) SHA1_Init(a)
163 #define MD_Update(a,b,c) SHA1_Update(a,b,c)
164 #define MD_Final(a,b) SHA1_Final(a,b)
165 #define MD(a,b,c) SHA1(a,b,c)
166 #elif defined(USE_MDC2_RAND)
167 #include <openssl/mdc2.h>
168 #define MD_DIGEST_LENGTH MDC2_DIGEST_LENGTH
169 #define MD_CTX MDC2_CTX
170 #define MD_Init(a) MDC2_Init(a)
171 #define MD_Update(a,b,c) MDC2_Update(a,b,c)
172 #define MD_Final(a,b) MDC2_Final(a,b)
173 #define MD(a,b,c) MDC2(a,b,c)
174 #elif defined(USE_MD2_RAND)
175 #include <openssl/md2.h>
176 #define MD_DIGEST_LENGTH MD2_DIGEST_LENGTH
177 #define MD_CTX MD2_CTX
178 #define MD_Init(a) MD2_Init(a)
179 #define MD_Update(a,b,c) MD2_Update(a,b,c)
180 #define MD_Final(a,b) MD2_Final(a,b)
181 #define MD(a,b,c) MD2(a,b,c)
184 #include <openssl/rand.h>
190 /* #define NORAND 1 */
191 /* #define PREDICT 1 */
193 #define STATE_SIZE 1023
194 static int state_num=0,state_index=0;
195 static unsigned char state[STATE_SIZE+MD_DIGEST_LENGTH];
196 static unsigned char md[MD_DIGEST_LENGTH];
197 static long md_count[2]={0,0};
198 static double entropy=0;
199 static int initialized=0;
202 int rand_predictable=0;
205 const char *RAND_version="RAND" OPENSSL_VERSION_PTEXT;
207 static void ssleay_rand_cleanup(void);
208 static void ssleay_rand_seed(const void *buf, int num);
209 static void ssleay_rand_add(const void *buf, int num, double add_entropy);
210 static int ssleay_rand_bytes(unsigned char *buf, int num);
211 static int ssleay_rand_pseudo_bytes(unsigned char *buf, int num);
212 static int ssleay_rand_status(void);
214 RAND_METHOD rand_ssleay_meth={
219 ssleay_rand_pseudo_bytes,
223 RAND_METHOD *RAND_SSLeay(void)
225 return(&rand_ssleay_meth);
228 static void ssleay_rand_cleanup(void)
230 memset(state,0,sizeof(state));
233 memset(md,0,MD_DIGEST_LENGTH);
239 static void ssleay_rand_add(const void *buf, int num, double add)
243 unsigned char local_md[MD_DIGEST_LENGTH];
251 * (Based on the rand(3) manpage)
253 * The input is chopped up into units of 20 bytes (or less for
254 * the last block). Each of these blocks is run through the hash
255 * function as follows: The data passed to the hash function
256 * is the current 'md', the same number of bytes from the 'state'
257 * (the location determined by in incremented looping index) as
258 * the current 'block', the new key data 'block', and 'count'
259 * (which is incremented after each use).
260 * The result of this is kept in 'md' and also xored into the
261 * 'state' at the same locations that were used as input into the
265 CRYPTO_w_lock(CRYPTO_LOCK_RAND);
268 /* use our own copies of the counters so that even
269 * if a concurrent thread seeds with exactly the
270 * same data and uses the same subarray there's _some_
272 md_c[0] = md_count[0];
273 md_c[1] = md_count[1];
275 memcpy(local_md, md, sizeof md);
277 /* state_index <= state_num <= STATE_SIZE */
279 if (state_index >= STATE_SIZE)
281 state_index%=STATE_SIZE;
282 state_num=STATE_SIZE;
284 else if (state_num < STATE_SIZE)
286 if (state_index > state_num)
287 state_num=state_index;
289 /* state_index <= state_num <= STATE_SIZE */
291 /* state[st_idx], ..., state[(st_idx + num - 1) % STATE_SIZE]
292 * are what we will use now, but other threads may use them
295 md_count[1] += (num / MD_DIGEST_LENGTH) + (num % MD_DIGEST_LENGTH > 0);
297 CRYPTO_w_unlock(CRYPTO_LOCK_RAND);
299 for (i=0; i<num; i+=MD_DIGEST_LENGTH)
302 j=(j > MD_DIGEST_LENGTH)?MD_DIGEST_LENGTH:j;
305 MD_Update(&m,local_md,MD_DIGEST_LENGTH);
306 k=(st_idx+j)-STATE_SIZE;
309 MD_Update(&m,&(state[st_idx]),j-k);
310 MD_Update(&m,&(state[0]),k);
313 MD_Update(&m,&(state[st_idx]),j);
316 MD_Update(&m,(unsigned char *)&(md_c[0]),sizeof(md_c));
317 MD_Final(local_md,&m);
320 buf=(const char *)buf + j;
324 /* Parallel threads may interfere with this,
325 * but always each byte of the new state is
326 * the XOR of some previous value of its
327 * and local_md (itermediate values may be lost).
328 * Alway using locking could hurt performance more
329 * than necessary given that conflicts occur only
330 * when the total seeding is longer than the random
332 state[st_idx++]^=local_md[k];
333 if (st_idx >= STATE_SIZE)
337 memset((char *)&m,0,sizeof(m));
339 CRYPTO_w_lock(CRYPTO_LOCK_RAND);
340 /* Don't just copy back local_md into md -- this could mean that
341 * other thread's seeding remains without effect (except for
342 * the incremented counter). By XORing it we keep at least as
343 * much entropy as fits into md. */
344 for (k = 0; k < sizeof md; k++)
346 md[k] ^= local_md[k];
348 if (entropy < ENTROPY_NEEDED) /* stop counting when we have enough */
350 CRYPTO_w_unlock(CRYPTO_LOCK_RAND);
353 assert(md_c[1] == md_count[1]);
357 static void ssleay_rand_seed(const void *buf, int num)
359 ssleay_rand_add(buf, num, num);
362 static void ssleay_rand_initialize(void) /* not exported in RAND_METHOD */
365 #ifndef GETPID_IS_MEANINGLESS
366 pid_t curr_pid = getpid();
376 CRYPTO_w_unlock(CRYPTO_LOCK_RAND);
377 /* put in some default random data, we need more than just this */
378 #ifndef GETPID_IS_MEANINGLESS
380 RAND_add(&l,sizeof(l),0);
382 RAND_add(&l,sizeof(l),0);
385 RAND_add(&l,sizeof(l),0);
388 /* Use a random entropy pool device. Linux, FreeBSD and OpenBSD
389 * have this. Use /dev/urandom if you can as /dev/random may block
390 * if it runs out of random entries. */
392 if ((fh = fopen(DEVRANDOM, "r")) != NULL)
394 unsigned char tmpbuf[ENTROPY_NEEDED];
397 setvbuf(fh, NULL, _IONBF, 0);
398 n=fread((unsigned char *)tmpbuf,1,ENTROPY_NEEDED,fh);
400 RAND_add(tmpbuf,sizeof tmpbuf,n);
405 memset(state,0,STATE_SIZE);
406 memset(md,0,MD_DIGEST_LENGTH);
408 CRYPTO_w_lock(CRYPTO_LOCK_RAND);
412 static int ssleay_rand_bytes(unsigned char *buf, int num)
414 static volatile int stirred_pool = 0;
415 int i,j,k,st_num,st_idx;
418 unsigned char local_md[MD_DIGEST_LENGTH];
420 #ifndef GETPID_IS_MEANINGLESS
421 pid_t curr_pid = getpid();
423 int do_stir_pool = 0;
426 if (rand_predictable)
428 static unsigned char val=0;
430 for (i=0; i<num; i++)
437 * (Based on the rand(3) manpage:)
439 * For each group of 10 bytes (or less), we do the following:
441 * Input into the hash function the top 10 bytes from the
442 * local 'md' (which is initialized from the global 'md'
443 * before any bytes are generated), the bytes that are
444 * to be overwritten by the random bytes, and bytes from the
445 * 'state' (incrementing looping index). From this digest output
446 * (which is kept in 'md'), the top (up to) 10 bytes are
447 * returned to the caller and the bottom (up to) 10 bytes are xored
449 * Finally, after we have finished 'num' random bytes for the
450 * caller, 'count' (which is incremented) and the local and global 'md'
451 * are fed into the hash function and the results are kept in the
455 CRYPTO_w_lock(CRYPTO_LOCK_RAND);
458 ssleay_rand_initialize();
463 ok = (entropy >= ENTROPY_NEEDED);
466 /* If the PRNG state is not yet unpredictable, then seeing
467 * the PRNG output may help attackers to determine the new
468 * state; thus we have to decrease the entropy estimate.
469 * Once we've had enough initial seeding we don't bother to
470 * adjust the entropy count, though, because we're not ambitious
471 * to provide *information-theoretic* randomness.
473 * NOTE: This approach fails if the program forks before
474 * we have enough entropy. Entropy should be collected
475 * in a separate input pool and be transferred to the
476 * output pool only when the entropy limit has been reached.
485 /* Our output function chains only half of 'md', so we better
486 * make sure that the required entropy gets 'evenly distributed'
487 * through 'state', our randomness pool. The input function
488 * (ssleay_rand_add) chains all of 'md', which makes it more
489 * suitable for this purpose.
492 int n = STATE_SIZE; /* so that the complete pool gets accessed */
495 #if MD_DIGEST_LENGTH > 20
496 # error "Please adjust DUMMY_SEED."
498 #define DUMMY_SEED "...................." /* at least MD_DIGEST_LENGTH */
499 /* Note that the seed does not matter, it's just that
500 * ssleay_rand_add expects to have something to hash. */
501 ssleay_rand_add(DUMMY_SEED, MD_DIGEST_LENGTH, 0.0);
502 n -= MD_DIGEST_LENGTH;
510 md_c[0] = md_count[0];
511 md_c[1] = md_count[1];
512 memcpy(local_md, md, sizeof md);
515 if (state_index > state_num)
516 state_index %= state_num;
518 /* state[st_idx], ..., state[(st_idx + num - 1) % st_num]
519 * are now ours (but other threads may use them too) */
522 CRYPTO_w_unlock(CRYPTO_LOCK_RAND);
526 j=(num >= MD_DIGEST_LENGTH/2)?MD_DIGEST_LENGTH/2:num;
529 #ifndef GETPID_IS_MEANINGLESS
530 if (curr_pid) /* just in the first iteration to save time */
532 MD_Update(&m,(unsigned char*)&curr_pid,sizeof curr_pid);
536 MD_Update(&m,&(local_md[MD_DIGEST_LENGTH/2]),MD_DIGEST_LENGTH/2);
537 MD_Update(&m,(unsigned char *)&(md_c[0]),sizeof(md_c));
539 MD_Update(&m,buf,j); /* purify complains */
544 MD_Update(&m,&(state[st_idx]),j-k);
545 MD_Update(&m,&(state[0]),k);
548 MD_Update(&m,&(state[st_idx]),j);
549 MD_Final(local_md,&m);
553 state[st_idx++]^=local_md[i]; /* may compete with other threads */
554 *(buf++)=local_md[i+MD_DIGEST_LENGTH/2];
555 if (st_idx >= st_num)
561 MD_Update(&m,(unsigned char *)&(md_c[0]),sizeof(md_c));
562 MD_Update(&m,local_md,MD_DIGEST_LENGTH);
563 CRYPTO_w_lock(CRYPTO_LOCK_RAND);
564 MD_Update(&m,md,MD_DIGEST_LENGTH);
566 CRYPTO_w_unlock(CRYPTO_LOCK_RAND);
568 memset(&m,0,sizeof(m));
573 RANDerr(RAND_F_SSLEAY_RAND_BYTES,RAND_R_PRNG_NOT_SEEDED);
578 /* pseudo-random bytes that are guaranteed to be unique but not
580 static int ssleay_rand_pseudo_bytes(unsigned char *buf, int num)
584 ret = RAND_bytes(buf, num);
587 err = ERR_peek_error();
588 if (ERR_GET_LIB(err) == ERR_LIB_RAND &&
589 ERR_GET_REASON(err) == RAND_R_PRNG_NOT_SEEDED)
590 (void)ERR_get_error();
595 static int ssleay_rand_status(void)
599 CRYPTO_w_lock(CRYPTO_LOCK_RAND);
602 ssleay_rand_initialize();
603 ret = entropy >= ENTROPY_NEEDED;
605 CRYPTO_w_unlock(CRYPTO_LOCK_RAND);