1 | /* crypto/rand/md_rand.c */ |
2 | /* Copyright (C) 1995-1998 Eric Young (eay@cryptsoft.com) |
3 | * All rights reserved. |
4 | * |
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. |
8 | * |
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). |
15 | * |
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. |
22 | * |
23 | * Redistribution and use in source and binary forms, with or without |
24 | * modification, are permitted provided that the following conditions |
25 | * are met: |
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)" |
40 | * |
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 |
51 | * SUCH DAMAGE. |
52 | * |
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.] |
57 | */ |
58 | /* ==================================================================== |
59 | * Copyright (c) 1998-2001 The OpenSSL Project. All rights reserved. |
60 | * |
61 | * Redistribution and use in source and binary forms, with or without |
62 | * modification, are permitted provided that the following conditions |
63 | * are met: |
64 | * |
65 | * 1. Redistributions of source code must retain the above copyright |
66 | * notice, this list of conditions and the following disclaimer. |
67 | * |
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 |
71 | * distribution. |
72 | * |
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/)" |
77 | * |
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. |
82 | * |
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. |
86 | * |
87 | * 6. Redistributions of any form whatsoever must retain the following |
88 | * acknowledgment: |
89 | * "This product includes software developed by the OpenSSL Project |
90 | * for use in the OpenSSL Toolkit (http://www.openssl.org/)" |
91 | * |
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 | * ==================================================================== |
105 | * |
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). |
109 | * |
110 | */ |
111 | |
112 | #define OPENSSL_FIPSEVP |
113 | |
114 | #ifdef MD_RAND_DEBUG |
115 | # ifndef NDEBUG |
116 | # define NDEBUG |
117 | # endif |
118 | #endif |
119 | |
120 | #include <assert.h> |
121 | #include <stdio.h> |
122 | #include <string.h> |
123 | |
124 | #include "e_os.h" |
125 | |
126 | #include <openssl/crypto.h> |
127 | #include <openssl/rand.h> |
128 | #include "rand_lcl.h" |
129 | |
130 | #include <openssl/err.h> |
131 | |
132 | #ifdef BN_DEBUG |
133 | # define PREDICT |
134 | #endif |
135 | |
136 | /* #define PREDICT 1 */ |
137 | |
138 | #define STATE_SIZE 1023 |
139 | static int state_num=0,state_index=0; |
140 | static unsigned char state[STATE_SIZE+MD_DIGEST_LENGTH]; |
141 | static unsigned char md[MD_DIGEST_LENGTH]; |
142 | static long md_count[2]={0,0}; |
143 | static double entropy=0; |
144 | static int initialized=0; |
145 | |
146 | static unsigned int crypto_lock_rand = 0; /* may be set only when a thread |
147 | * holds CRYPTO_LOCK_RAND |
148 | * (to prevent double locking) */ |
149 | /* access to lockin_thread is synchronized by CRYPTO_LOCK_RAND2 */ |
150 | static CRYPTO_THREADID locking_threadid; /* valid iff crypto_lock_rand is set */ |
151 | |
152 | |
153 | #ifdef PREDICT |
154 | int rand_predictable=0; |
155 | #endif |
156 | |
157 | const char RAND_version[]="RAND" OPENSSL_VERSION_PTEXT; |
158 | |
159 | static void ssleay_rand_cleanup(void); |
160 | static void ssleay_rand_seed(const void *buf, int num); |
161 | static void ssleay_rand_add(const void *buf, int num, double add_entropy); |
162 | static int ssleay_rand_bytes(unsigned char *buf, int num, int pseudo); |
163 | static int ssleay_rand_nopseudo_bytes(unsigned char *buf, int num); |
164 | static int ssleay_rand_pseudo_bytes(unsigned char *buf, int num); |
165 | static int ssleay_rand_status(void); |
166 | |
167 | RAND_METHOD rand_ssleay_meth={ |
168 | ssleay_rand_seed, |
169 | ssleay_rand_nopseudo_bytes, |
170 | ssleay_rand_cleanup, |
171 | ssleay_rand_add, |
172 | ssleay_rand_pseudo_bytes, |
173 | ssleay_rand_status |
174 | }; |
175 | |
176 | RAND_METHOD *RAND_SSLeay(void) |
177 | { |
178 | return(&rand_ssleay_meth); |
179 | } |
180 | |
181 | static void ssleay_rand_cleanup(void) |
182 | { |
183 | OPENSSL_cleanse(state,sizeof(state)); |
184 | state_num=0; |
185 | state_index=0; |
186 | OPENSSL_cleanse(md,MD_DIGEST_LENGTH); |
187 | md_count[0]=0; |
188 | md_count[1]=0; |
189 | entropy=0; |
190 | initialized=0; |
191 | } |
192 | |
193 | static void ssleay_rand_add(const void *buf, int num, double add) |
194 | { |
195 | int i,j,k,st_idx; |
196 | long md_c[2]; |
197 | unsigned char local_md[MD_DIGEST_LENGTH]; |
198 | EVP_MD_CTX m; |
199 | int do_not_lock; |
200 | |
201 | /* |
202 | * (Based on the rand(3) manpage) |
203 | * |
204 | * The input is chopped up into units of 20 bytes (or less for |
205 | * the last block). Each of these blocks is run through the hash |
206 | * function as follows: The data passed to the hash function |
207 | * is the current 'md', the same number of bytes from the 'state' |
208 | * (the location determined by in incremented looping index) as |
209 | * the current 'block', the new key data 'block', and 'count' |
210 | * (which is incremented after each use). |
211 | * The result of this is kept in 'md' and also xored into the |
212 | * 'state' at the same locations that were used as input into the |
213 | * hash function. |
214 | */ |
215 | |
216 | /* check if we already have the lock */ |
217 | if (crypto_lock_rand) |
218 | { |
219 | CRYPTO_THREADID cur; |
220 | CRYPTO_THREADID_current(&cur); |
221 | CRYPTO_r_lock(CRYPTO_LOCK_RAND2); |
222 | do_not_lock = !CRYPTO_THREADID_cmp(&locking_threadid, &cur); |
223 | CRYPTO_r_unlock(CRYPTO_LOCK_RAND2); |
224 | } |
225 | else |
226 | do_not_lock = 0; |
227 | |
228 | if (!do_not_lock) CRYPTO_w_lock(CRYPTO_LOCK_RAND); |
229 | st_idx=state_index; |
230 | |
231 | /* use our own copies of the counters so that even |
232 | * if a concurrent thread seeds with exactly the |
233 | * same data and uses the same subarray there's _some_ |
234 | * difference */ |
235 | md_c[0] = md_count[0]; |
236 | md_c[1] = md_count[1]; |
237 | |
238 | memcpy(local_md, md, sizeof md); |
239 | |
240 | /* state_index <= state_num <= STATE_SIZE */ |
241 | state_index += num; |
242 | if (state_index >= STATE_SIZE) |
243 | { |
244 | state_index%=STATE_SIZE; |
245 | state_num=STATE_SIZE; |
246 | } |
247 | else if (state_num < STATE_SIZE) |
248 | { |
249 | if (state_index > state_num) |
250 | state_num=state_index; |
251 | } |
252 | /* state_index <= state_num <= STATE_SIZE */ |
253 | |
254 | /* state[st_idx], ..., state[(st_idx + num - 1) % STATE_SIZE] |
255 | * are what we will use now, but other threads may use them |
256 | * as well */ |
257 | |
258 | md_count[1] += (num / MD_DIGEST_LENGTH) + (num % MD_DIGEST_LENGTH > 0); |
259 | |
260 | if (!do_not_lock) CRYPTO_w_unlock(CRYPTO_LOCK_RAND); |
261 | |
262 | EVP_MD_CTX_init(&m); |
263 | for (i=0; i<num; i+=MD_DIGEST_LENGTH) |
264 | { |
265 | j=(num-i); |
266 | j=(j > MD_DIGEST_LENGTH)?MD_DIGEST_LENGTH:j; |
267 | |
268 | MD_Init(&m); |
269 | MD_Update(&m,local_md,MD_DIGEST_LENGTH); |
270 | k=(st_idx+j)-STATE_SIZE; |
271 | if (k > 0) |
272 | { |
273 | MD_Update(&m,&(state[st_idx]),j-k); |
274 | MD_Update(&m,&(state[0]),k); |
275 | } |
276 | else |
277 | MD_Update(&m,&(state[st_idx]),j); |
278 | |
279 | /* DO NOT REMOVE THE FOLLOWING CALL TO MD_Update()! */ |
280 | MD_Update(&m,buf,j); |
281 | /* We know that line may cause programs such as |
282 | purify and valgrind to complain about use of |
283 | uninitialized data. The problem is not, it's |
284 | with the caller. Removing that line will make |
285 | sure you get really bad randomness and thereby |
286 | other problems such as very insecure keys. */ |
287 | |
288 | MD_Update(&m,(unsigned char *)&(md_c[0]),sizeof(md_c)); |
289 | MD_Final(&m,local_md); |
290 | md_c[1]++; |
291 | |
292 | buf=(const char *)buf + j; |
293 | |
294 | for (k=0; k<j; k++) |
295 | { |
296 | /* Parallel threads may interfere with this, |
297 | * but always each byte of the new state is |
298 | * the XOR of some previous value of its |
299 | * and local_md (itermediate values may be lost). |
300 | * Alway using locking could hurt performance more |
301 | * than necessary given that conflicts occur only |
302 | * when the total seeding is longer than the random |
303 | * state. */ |
304 | state[st_idx++]^=local_md[k]; |
305 | if (st_idx >= STATE_SIZE) |
306 | st_idx=0; |
307 | } |
308 | } |
309 | EVP_MD_CTX_cleanup(&m); |
310 | |
311 | if (!do_not_lock) CRYPTO_w_lock(CRYPTO_LOCK_RAND); |
312 | /* Don't just copy back local_md into md -- this could mean that |
313 | * other thread's seeding remains without effect (except for |
314 | * the incremented counter). By XORing it we keep at least as |
315 | * much entropy as fits into md. */ |
316 | for (k = 0; k < (int)sizeof(md); k++) |
317 | { |
318 | md[k] ^= local_md[k]; |
319 | } |
320 | if (entropy < ENTROPY_NEEDED) /* stop counting when we have enough */ |
321 | entropy += add; |
322 | if (!do_not_lock) CRYPTO_w_unlock(CRYPTO_LOCK_RAND); |
323 | |
324 | #if !defined(OPENSSL_THREADS) && !defined(OPENSSL_SYS_WIN32) |
325 | assert(md_c[1] == md_count[1]); |
326 | #endif |
327 | } |
328 | |
329 | static void ssleay_rand_seed(const void *buf, int num) |
330 | { |
331 | ssleay_rand_add(buf, num, (double)num); |
332 | } |
333 | |
334 | static int ssleay_rand_bytes(unsigned char *buf, int num, int pseudo) |
335 | { |
336 | static volatile int stirred_pool = 0; |
337 | int i,j,k,st_num,st_idx; |
338 | int num_ceil; |
339 | int ok; |
340 | long md_c[2]; |
341 | unsigned char local_md[MD_DIGEST_LENGTH]; |
342 | EVP_MD_CTX m; |
343 | #ifndef GETPID_IS_MEANINGLESS |
344 | pid_t curr_pid = getpid(); |
345 | #endif |
346 | int do_stir_pool = 0; |
347 | |
348 | #ifdef PREDICT |
349 | if (rand_predictable) |
350 | { |
351 | static unsigned char val=0; |
352 | |
353 | for (i=0; i<num; i++) |
354 | buf[i]=val++; |
355 | return(1); |
356 | } |
357 | #endif |
358 | |
359 | if (num <= 0) |
360 | return 1; |
361 | |
362 | EVP_MD_CTX_init(&m); |
363 | /* round upwards to multiple of MD_DIGEST_LENGTH/2 */ |
364 | num_ceil = (1 + (num-1)/(MD_DIGEST_LENGTH/2)) * (MD_DIGEST_LENGTH/2); |
365 | |
366 | /* |
367 | * (Based on the rand(3) manpage:) |
368 | * |
369 | * For each group of 10 bytes (or less), we do the following: |
370 | * |
371 | * Input into the hash function the local 'md' (which is initialized from |
372 | * the global 'md' before any bytes are generated), the bytes that are to |
373 | * be overwritten by the random bytes, and bytes from the 'state' |
374 | * (incrementing looping index). From this digest output (which is kept |
375 | * in 'md'), the top (up to) 10 bytes are returned to the caller and the |
376 | * bottom 10 bytes are xored into the 'state'. |
377 | * |
378 | * Finally, after we have finished 'num' random bytes for the |
379 | * caller, 'count' (which is incremented) and the local and global 'md' |
380 | * are fed into the hash function and the results are kept in the |
381 | * global 'md'. |
382 | */ |
383 | |
384 | CRYPTO_w_lock(CRYPTO_LOCK_RAND); |
385 | |
386 | /* prevent ssleay_rand_bytes() from trying to obtain the lock again */ |
387 | CRYPTO_w_lock(CRYPTO_LOCK_RAND2); |
388 | CRYPTO_THREADID_current(&locking_threadid); |
389 | CRYPTO_w_unlock(CRYPTO_LOCK_RAND2); |
390 | crypto_lock_rand = 1; |
391 | |
392 | if (!initialized) |
393 | { |
394 | RAND_poll(); |
395 | initialized = 1; |
396 | } |
397 | |
398 | if (!stirred_pool) |
399 | do_stir_pool = 1; |
400 | |
401 | ok = (entropy >= ENTROPY_NEEDED); |
402 | if (!ok) |
403 | { |
404 | /* If the PRNG state is not yet unpredictable, then seeing |
405 | * the PRNG output may help attackers to determine the new |
406 | * state; thus we have to decrease the entropy estimate. |
407 | * Once we've had enough initial seeding we don't bother to |
408 | * adjust the entropy count, though, because we're not ambitious |
409 | * to provide *information-theoretic* randomness. |
410 | * |
411 | * NOTE: This approach fails if the program forks before |
412 | * we have enough entropy. Entropy should be collected |
413 | * in a separate input pool and be transferred to the |
414 | * output pool only when the entropy limit has been reached. |
415 | */ |
416 | entropy -= num; |
417 | if (entropy < 0) |
418 | entropy = 0; |
419 | } |
420 | |
421 | if (do_stir_pool) |
422 | { |
423 | /* In the output function only half of 'md' remains secret, |
424 | * so we better make sure that the required entropy gets |
425 | * 'evenly distributed' through 'state', our randomness pool. |
426 | * The input function (ssleay_rand_add) chains all of 'md', |
427 | * which makes it more suitable for this purpose. |
428 | */ |
429 | |
430 | int n = STATE_SIZE; /* so that the complete pool gets accessed */ |
431 | while (n > 0) |
432 | { |
433 | #if MD_DIGEST_LENGTH > 20 |
434 | # error "Please adjust DUMMY_SEED." |
435 | #endif |
436 | #define DUMMY_SEED "...................." /* at least MD_DIGEST_LENGTH */ |
437 | /* Note that the seed does not matter, it's just that |
438 | * ssleay_rand_add expects to have something to hash. */ |
439 | ssleay_rand_add(DUMMY_SEED, MD_DIGEST_LENGTH, 0.0); |
440 | n -= MD_DIGEST_LENGTH; |
441 | } |
442 | if (ok) |
443 | stirred_pool = 1; |
444 | } |
445 | |
446 | st_idx=state_index; |
447 | st_num=state_num; |
448 | md_c[0] = md_count[0]; |
449 | md_c[1] = md_count[1]; |
450 | memcpy(local_md, md, sizeof md); |
451 | |
452 | state_index+=num_ceil; |
453 | if (state_index > state_num) |
454 | state_index %= state_num; |
455 | |
456 | /* state[st_idx], ..., state[(st_idx + num_ceil - 1) % st_num] |
457 | * are now ours (but other threads may use them too) */ |
458 | |
459 | md_count[0] += 1; |
460 | |
461 | /* before unlocking, we must clear 'crypto_lock_rand' */ |
462 | crypto_lock_rand = 0; |
463 | CRYPTO_w_unlock(CRYPTO_LOCK_RAND); |
464 | |
465 | while (num > 0) |
466 | { |
467 | /* num_ceil -= MD_DIGEST_LENGTH/2 */ |
468 | j=(num >= MD_DIGEST_LENGTH/2)?MD_DIGEST_LENGTH/2:num; |
469 | num-=j; |
470 | MD_Init(&m); |
471 | #ifndef GETPID_IS_MEANINGLESS |
472 | if (curr_pid) /* just in the first iteration to save time */ |
473 | { |
474 | MD_Update(&m,(unsigned char*)&curr_pid,sizeof curr_pid); |
475 | curr_pid = 0; |
476 | } |
477 | #endif |
478 | MD_Update(&m,local_md,MD_DIGEST_LENGTH); |
479 | MD_Update(&m,(unsigned char *)&(md_c[0]),sizeof(md_c)); |
480 | |
481 | #ifndef PURIFY /* purify complains */ |
482 | /* The following line uses the supplied buffer as a small |
483 | * source of entropy: since this buffer is often uninitialised |
484 | * it may cause programs such as purify or valgrind to |
485 | * complain. So for those builds it is not used: the removal |
486 | * of such a small source of entropy has negligible impact on |
487 | * security. |
488 | */ |
489 | MD_Update(&m,buf,j); |
490 | #endif |
491 | |
492 | k=(st_idx+MD_DIGEST_LENGTH/2)-st_num; |
493 | if (k > 0) |
494 | { |
495 | MD_Update(&m,&(state[st_idx]),MD_DIGEST_LENGTH/2-k); |
496 | MD_Update(&m,&(state[0]),k); |
497 | } |
498 | else |
499 | MD_Update(&m,&(state[st_idx]),MD_DIGEST_LENGTH/2); |
500 | MD_Final(&m,local_md); |
501 | |
502 | for (i=0; i<MD_DIGEST_LENGTH/2; i++) |
503 | { |
504 | state[st_idx++]^=local_md[i]; /* may compete with other threads */ |
505 | if (st_idx >= st_num) |
506 | st_idx=0; |
507 | if (i < j) |
508 | *(buf++)=local_md[i+MD_DIGEST_LENGTH/2]; |
509 | } |
510 | } |
511 | |
512 | MD_Init(&m); |
513 | MD_Update(&m,(unsigned char *)&(md_c[0]),sizeof(md_c)); |
514 | MD_Update(&m,local_md,MD_DIGEST_LENGTH); |
515 | CRYPTO_w_lock(CRYPTO_LOCK_RAND); |
516 | MD_Update(&m,md,MD_DIGEST_LENGTH); |
517 | MD_Final(&m,md); |
518 | CRYPTO_w_unlock(CRYPTO_LOCK_RAND); |
519 | |
520 | EVP_MD_CTX_cleanup(&m); |
521 | if (ok) |
522 | return(1); |
523 | else if (pseudo) |
524 | return 0; |
525 | else |
526 | { |
527 | RANDerr(RAND_F_SSLEAY_RAND_BYTES,RAND_R_PRNG_NOT_SEEDED); |
528 | ERR_add_error_data(1, "You need to read the OpenSSL FAQ, " |
529 | "http://www.openssl.org/support/faq.html" ); |
530 | return(0); |
531 | } |
532 | } |
533 | |
534 | static int ssleay_rand_nopseudo_bytes(unsigned char *buf, int num) |
535 | { |
536 | return ssleay_rand_bytes(buf, num, 0); |
537 | } |
538 | |
539 | /* pseudo-random bytes that are guaranteed to be unique but not |
540 | unpredictable */ |
541 | static int ssleay_rand_pseudo_bytes(unsigned char *buf, int num) |
542 | { |
543 | return ssleay_rand_bytes(buf, num, 1); |
544 | } |
545 | |
546 | static int ssleay_rand_status(void) |
547 | { |
548 | CRYPTO_THREADID cur; |
549 | int ret; |
550 | int do_not_lock; |
551 | |
552 | CRYPTO_THREADID_current(&cur); |
553 | /* check if we already have the lock |
554 | * (could happen if a RAND_poll() implementation calls RAND_status()) */ |
555 | if (crypto_lock_rand) |
556 | { |
557 | CRYPTO_r_lock(CRYPTO_LOCK_RAND2); |
558 | do_not_lock = !CRYPTO_THREADID_cmp(&locking_threadid, &cur); |
559 | CRYPTO_r_unlock(CRYPTO_LOCK_RAND2); |
560 | } |
561 | else |
562 | do_not_lock = 0; |
563 | |
564 | if (!do_not_lock) |
565 | { |
566 | CRYPTO_w_lock(CRYPTO_LOCK_RAND); |
567 | |
568 | /* prevent ssleay_rand_bytes() from trying to obtain the lock again */ |
569 | CRYPTO_w_lock(CRYPTO_LOCK_RAND2); |
570 | CRYPTO_THREADID_cpy(&locking_threadid, &cur); |
571 | CRYPTO_w_unlock(CRYPTO_LOCK_RAND2); |
572 | crypto_lock_rand = 1; |
573 | } |
574 | |
575 | if (!initialized) |
576 | { |
577 | RAND_poll(); |
578 | initialized = 1; |
579 | } |
580 | |
581 | ret = entropy >= ENTROPY_NEEDED; |
582 | |
583 | if (!do_not_lock) |
584 | { |
585 | /* before unlocking, we must clear 'crypto_lock_rand' */ |
586 | crypto_lock_rand = 0; |
587 | |
588 | CRYPTO_w_unlock(CRYPTO_LOCK_RAND); |
589 | } |
590 | |
591 | return ret; |
592 | } |
593 | |