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/crypto.h>
132 #include <openssl/rand.h>
133 #include <openssl/async.h>
134 #include "rand_lcl.h"
136 #include <openssl/err.h>
139 # include <openssl/fips.h>
146 /* #define PREDICT 1 */
148 #define STATE_SIZE 1023
149 static int state_num
= 0, state_index
= 0;
150 static unsigned char state
[STATE_SIZE
+ MD_DIGEST_LENGTH
];
151 static unsigned char md
[MD_DIGEST_LENGTH
];
152 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 (to
159 * prevent double locking) */
160 /* access to lockin_thread is synchronized by CRYPTO_LOCK_RAND2 */
161 /* valid iff crypto_lock_rand is set */
162 static CRYPTO_THREADID locking_threadid
;
165 int rand_predictable
= 0;
168 static void rand_hw_seed(EVP_MD_CTX
*ctx
);
170 static void rand_cleanup(void);
171 static int rand_seed(const void *buf
, int num
);
172 static int rand_add(const void *buf
, int num
, double add_entropy
);
173 static int rand_bytes(unsigned char *buf
, int num
, int pseudo
);
174 static int rand_nopseudo_bytes(unsigned char *buf
, int num
);
175 #ifndef OPENSSL_NO_DEPRECATED
176 static int rand_pseudo_bytes(unsigned char *buf
, int num
);
178 static int rand_status(void);
180 static RAND_METHOD rand_meth
= {
185 #ifndef OPENSSL_NO_DEPRECATED
193 RAND_METHOD
*RAND_OpenSSL(void)
198 static void rand_cleanup(void)
200 OPENSSL_cleanse(state
, sizeof(state
));
203 OPENSSL_cleanse(md
, MD_DIGEST_LENGTH
);
210 static int rand_add(const void *buf
, int num
, double add
)
214 unsigned char local_md
[MD_DIGEST_LENGTH
];
223 * (Based on the rand(3) manpage)
225 * The input is chopped up into units of 20 bytes (or less for
226 * the last block). Each of these blocks is run through the hash
227 * function as follows: The data passed to the hash function
228 * is the current 'md', the same number of bytes from the 'state'
229 * (the location determined by in incremented looping index) as
230 * the current 'block', the new key data 'block', and 'count'
231 * (which is incremented after each use).
232 * The result of this is kept in 'md' and also xored into the
233 * 'state' at the same locations that were used as input into the
237 m
= EVP_MD_CTX_new();
241 /* check if we already have the lock */
242 if (crypto_lock_rand
) {
244 CRYPTO_THREADID_current(&cur
);
245 CRYPTO_r_lock(CRYPTO_LOCK_RAND2
);
246 do_not_lock
= !CRYPTO_THREADID_cmp(&locking_threadid
, &cur
);
247 CRYPTO_r_unlock(CRYPTO_LOCK_RAND2
);
252 CRYPTO_w_lock(CRYPTO_LOCK_RAND
);
253 st_idx
= state_index
;
256 * use our own copies of the counters so that even if a concurrent thread
257 * seeds with exactly the same data and uses the same subarray there's
260 md_c
[0] = md_count
[0];
261 md_c
[1] = md_count
[1];
263 memcpy(local_md
, md
, sizeof md
);
265 /* state_index <= state_num <= STATE_SIZE */
267 if (state_index
>= STATE_SIZE
) {
268 state_index
%= STATE_SIZE
;
269 state_num
= STATE_SIZE
;
270 } else if (state_num
< STATE_SIZE
) {
271 if (state_index
> state_num
)
272 state_num
= state_index
;
274 /* state_index <= state_num <= STATE_SIZE */
277 * state[st_idx], ..., state[(st_idx + num - 1) % STATE_SIZE] are what we
278 * will use now, but other threads may use them as well
281 md_count
[1] += (num
/ MD_DIGEST_LENGTH
) + (num
% MD_DIGEST_LENGTH
> 0);
284 CRYPTO_w_unlock(CRYPTO_LOCK_RAND
);
286 for (i
= 0; i
< num
; i
+= MD_DIGEST_LENGTH
) {
288 j
= (j
> MD_DIGEST_LENGTH
) ? MD_DIGEST_LENGTH
: j
;
292 if (!MD_Update(m
, local_md
, MD_DIGEST_LENGTH
))
294 k
= (st_idx
+ j
) - STATE_SIZE
;
296 if (!MD_Update(m
, &(state
[st_idx
]), j
- k
))
298 if (!MD_Update(m
, &(state
[0]), k
))
300 } else if (!MD_Update(m
, &(state
[st_idx
]), j
))
303 /* DO NOT REMOVE THE FOLLOWING CALL TO MD_Update()! */
304 if (!MD_Update(m
, buf
, j
))
307 * We know that line may cause programs such as purify and valgrind
308 * to complain about use of uninitialized data. The problem is not,
309 * it's with the caller. Removing that line will make sure you get
310 * really bad randomness and thereby other problems such as very
314 if (!MD_Update(m
, (unsigned char *)&(md_c
[0]), sizeof(md_c
)))
316 if (!MD_Final(m
, local_md
))
320 buf
= (const char *)buf
+ j
;
322 for (k
= 0; k
< j
; k
++) {
324 * Parallel threads may interfere with this, but always each byte
325 * of the new state is the XOR of some previous value of its and
326 * local_md (itermediate values may be lost). Alway using locking
327 * could hurt performance more than necessary given that
328 * conflicts occur only when the total seeding is longer than the
331 state
[st_idx
++] ^= local_md
[k
];
332 if (st_idx
>= STATE_SIZE
)
338 CRYPTO_w_lock(CRYPTO_LOCK_RAND
);
340 * Don't just copy back local_md into md -- this could mean that other
341 * thread's seeding remains without effect (except for the incremented
342 * counter). By XORing it we keep at least as much entropy as fits into
345 for (k
= 0; k
< (int)sizeof(md
); k
++) {
346 md
[k
] ^= local_md
[k
];
348 if (entropy
< ENTROPY_NEEDED
) /* stop counting when we have enough */
351 CRYPTO_w_unlock(CRYPTO_LOCK_RAND
);
353 #if !defined(OPENSSL_THREADS) && !defined(OPENSSL_SYS_WIN32)
354 assert(md_c
[1] == md_count
[1]);
362 static int rand_seed(const void *buf
, int num
)
364 return rand_add(buf
, num
, (double)num
);
367 static int rand_bytes(unsigned char *buf
, int num
, int pseudo
)
369 static volatile int stirred_pool
= 0;
370 int i
, j
, k
, st_num
, st_idx
;
374 unsigned char local_md
[MD_DIGEST_LENGTH
];
376 #ifndef GETPID_IS_MEANINGLESS
377 pid_t curr_pid
= getpid();
379 time_t curr_time
= time(NULL
);
380 int do_stir_pool
= 0;
381 /* time value for various platforms */
382 #ifdef OPENSSL_SYS_WIN32
387 SystemTimeToFileTime(&t
, &tv
);
389 GetSystemTimeAsFileTime(&tv
);
391 #elif defined(OPENSSL_SYS_VXWORKS)
393 clock_gettime(CLOCK_REALTIME
, &ts
);
394 #elif defined(OPENSSL_SYS_DSPBIOS)
395 unsigned long long tv
, OPENSSL_rdtsc();
396 tv
= OPENSSL_rdtsc();
399 gettimeofday(&tv
, NULL
);
403 if (rand_predictable
) {
404 static unsigned char val
= 0;
406 for (i
= 0; i
< num
; i
++)
415 m
= EVP_MD_CTX_new();
419 /* round upwards to multiple of MD_DIGEST_LENGTH/2 */
421 (1 + (num
- 1) / (MD_DIGEST_LENGTH
/ 2)) * (MD_DIGEST_LENGTH
/ 2);
424 * (Based on the rand(3) manpage:)
426 * For each group of 10 bytes (or less), we do the following:
428 * Input into the hash function the local 'md' (which is initialized from
429 * the global 'md' before any bytes are generated), the bytes that are to
430 * be overwritten by the random bytes, and bytes from the 'state'
431 * (incrementing looping index). From this digest output (which is kept
432 * in 'md'), the top (up to) 10 bytes are returned to the caller and the
433 * bottom 10 bytes are xored into the 'state'.
435 * Finally, after we have finished 'num' random bytes for the
436 * caller, 'count' (which is incremented) and the local and global 'md'
437 * are fed into the hash function and the results are kept in the
441 CRYPTO_w_lock(CRYPTO_LOCK_RAND
);
443 * We could end up in an async engine while holding this lock so ensure
444 * we don't pause and cause a deadlock
448 /* prevent rand_bytes() from trying to obtain the lock again */
449 CRYPTO_w_lock(CRYPTO_LOCK_RAND2
);
450 CRYPTO_THREADID_current(&locking_threadid
);
451 CRYPTO_w_unlock(CRYPTO_LOCK_RAND2
);
452 crypto_lock_rand
= 1;
462 ok
= (entropy
>= ENTROPY_NEEDED
);
465 * If the PRNG state is not yet unpredictable, then seeing the PRNG
466 * output may help attackers to determine the new state; thus we have
467 * to decrease the entropy estimate. Once we've had enough initial
468 * seeding we don't bother to adjust the entropy count, though,
469 * because we're not ambitious to provide *information-theoretic*
470 * randomness. NOTE: This approach fails if the program forks before
471 * we have enough entropy. Entropy should be collected in a separate
472 * input pool and be transferred to the output pool only when the
473 * entropy limit has been reached.
482 * In the output function only half of 'md' remains secret, so we
483 * better make sure that the required entropy gets 'evenly
484 * distributed' through 'state', our randomness pool. The input
485 * function (rand_add) chains all of 'md', which makes it more
486 * suitable for this purpose.
489 int n
= STATE_SIZE
; /* so that the complete pool gets accessed */
491 #if MD_DIGEST_LENGTH > 20
492 # error "Please adjust DUMMY_SEED."
494 #define DUMMY_SEED "...................." /* at least MD_DIGEST_LENGTH */
496 * Note that the seed does not matter, it's just that
497 * rand_add expects to have something to hash.
499 rand_add(DUMMY_SEED
, MD_DIGEST_LENGTH
, 0.0);
500 n
-= MD_DIGEST_LENGTH
;
506 st_idx
= state_index
;
508 md_c
[0] = md_count
[0];
509 md_c
[1] = md_count
[1];
510 memcpy(local_md
, md
, sizeof md
);
512 state_index
+= num_ceil
;
513 if (state_index
> state_num
)
514 state_index
%= state_num
;
517 * state[st_idx], ..., state[(st_idx + num_ceil - 1) % st_num] are now
518 * ours (but other threads may use them too)
523 /* before unlocking, we must clear 'crypto_lock_rand' */
524 crypto_lock_rand
= 0;
525 ASYNC_unblock_pause();
526 CRYPTO_w_unlock(CRYPTO_LOCK_RAND
);
529 /* num_ceil -= MD_DIGEST_LENGTH/2 */
530 j
= (num
>= MD_DIGEST_LENGTH
/ 2) ? MD_DIGEST_LENGTH
/ 2 : num
;
534 #ifndef GETPID_IS_MEANINGLESS
535 if (curr_pid
) { /* just in the first iteration to save time */
536 if (!MD_Update(m
, (unsigned char *)&curr_pid
, sizeof curr_pid
))
541 if (curr_time
) { /* just in the first iteration to save time */
542 if (!MD_Update(m
, (unsigned char *)&curr_time
, sizeof curr_time
))
544 if (!MD_Update(m
, (unsigned char *)&tv
, sizeof tv
))
549 if (!MD_Update(m
, local_md
, MD_DIGEST_LENGTH
))
551 if (!MD_Update(m
, (unsigned char *)&(md_c
[0]), sizeof(md_c
)))
554 #ifndef PURIFY /* purify complains */
556 * The following line uses the supplied buffer as a small source of
557 * entropy: since this buffer is often uninitialised it may cause
558 * programs such as purify or valgrind to complain. So for those
559 * builds it is not used: the removal of such a small source of
560 * entropy has negligible impact on security.
562 if (!MD_Update(m
, buf
, j
))
566 k
= (st_idx
+ MD_DIGEST_LENGTH
/ 2) - st_num
;
568 if (!MD_Update(m
, &(state
[st_idx
]), MD_DIGEST_LENGTH
/ 2 - k
))
570 if (!MD_Update(m
, &(state
[0]), k
))
572 } else if (!MD_Update(m
, &(state
[st_idx
]), MD_DIGEST_LENGTH
/ 2))
574 if (!MD_Final(m
, local_md
))
577 for (i
= 0; i
< MD_DIGEST_LENGTH
/ 2; i
++) {
578 /* may compete with other threads */
579 state
[st_idx
++] ^= local_md
[i
];
580 if (st_idx
>= st_num
)
583 *(buf
++) = local_md
[i
+ MD_DIGEST_LENGTH
/ 2];
588 || !MD_Update(m
, (unsigned char *)&(md_c
[0]), sizeof(md_c
))
589 || !MD_Update(m
, local_md
, MD_DIGEST_LENGTH
))
591 CRYPTO_w_lock(CRYPTO_LOCK_RAND
);
593 * Prevent deadlocks if we end up in an async engine
596 if (!MD_Update(m
, md
, MD_DIGEST_LENGTH
) || !MD_Final(m
, md
)) {
597 CRYPTO_w_unlock(CRYPTO_LOCK_RAND
);
600 ASYNC_unblock_pause();
601 CRYPTO_w_unlock(CRYPTO_LOCK_RAND
);
609 RANDerr(RAND_F_RAND_BYTES
, RAND_R_PRNG_NOT_SEEDED
);
610 ERR_add_error_data(1, "You need to read the OpenSSL FAQ, "
611 "http://www.openssl.org/support/faq.html");
615 RANDerr(RAND_F_RAND_BYTES
, ERR_R_EVP_LIB
);
619 RANDerr(RAND_F_RAND_BYTES
, ERR_R_MALLOC_FAILURE
);
625 static int rand_nopseudo_bytes(unsigned char *buf
, int num
)
627 return rand_bytes(buf
, num
, 0);
630 #ifndef OPENSSL_NO_DEPRECATED
632 * pseudo-random bytes that are guaranteed to be unique but not unpredictable
634 static int rand_pseudo_bytes(unsigned char *buf
, int num
)
636 return rand_bytes(buf
, num
, 1);
640 static int rand_status(void)
646 CRYPTO_THREADID_current(&cur
);
648 * check if we already have the lock (could happen if a RAND_poll()
649 * implementation calls RAND_status())
651 if (crypto_lock_rand
) {
652 CRYPTO_r_lock(CRYPTO_LOCK_RAND2
);
653 do_not_lock
= !CRYPTO_THREADID_cmp(&locking_threadid
, &cur
);
654 CRYPTO_r_unlock(CRYPTO_LOCK_RAND2
);
659 CRYPTO_w_lock(CRYPTO_LOCK_RAND
);
661 * Prevent deadlocks in case we end up in an async engine
666 * prevent rand_bytes() from trying to obtain the lock again
668 CRYPTO_w_lock(CRYPTO_LOCK_RAND2
);
669 CRYPTO_THREADID_cpy(&locking_threadid
, &cur
);
670 CRYPTO_w_unlock(CRYPTO_LOCK_RAND2
);
671 crypto_lock_rand
= 1;
679 ret
= entropy
>= ENTROPY_NEEDED
;
682 /* before unlocking, we must clear 'crypto_lock_rand' */
683 crypto_lock_rand
= 0;
685 ASYNC_unblock_pause();
686 CRYPTO_w_unlock(CRYPTO_LOCK_RAND
);
693 * rand_hw_seed: get seed data from any available hardware RNG. only
694 * currently supports rdrand.
697 /* Adapted from eng_rdrand.c */
699 #if (defined(__i386) || defined(__i386__) || defined(_M_IX86) || \
700 defined(__x86_64) || defined(__x86_64__) || \
701 defined(_M_AMD64) || defined (_M_X64)) && defined(OPENSSL_CPUID_OBJ)
703 # define RDRAND_CALLS 4
705 size_t OPENSSL_ia32_rdrand(void);
706 extern unsigned int OPENSSL_ia32cap_P
[];
708 static void rand_hw_seed(EVP_MD_CTX
*ctx
)
711 if (!(OPENSSL_ia32cap_P
[1] & (1 << (62 - 32))))
713 for (i
= 0; i
< RDRAND_CALLS
; i
++) {
715 rnd
= OPENSSL_ia32_rdrand();
718 MD_Update(ctx
, (unsigned char *)&rnd
, sizeof(size_t));
722 /* XOR an existing buffer with random data */
724 void rand_hw_xor(unsigned char *buf
, size_t num
)
727 if (!(OPENSSL_ia32cap_P
[1] & (1 << (62 - 32))))
729 while (num
>= sizeof(size_t)) {
730 rnd
= OPENSSL_ia32_rdrand();
733 *((size_t *)buf
) ^= rnd
;
734 buf
+= sizeof(size_t);
735 num
-= sizeof(size_t);
738 rnd
= OPENSSL_ia32_rdrand();
752 static void rand_hw_seed(EVP_MD_CTX
*ctx
)
757 void rand_hw_xor(unsigned char *buf
, size_t num
)