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12fb8c3d | 1 | /* |
3c7d0945 | 2 | * Copyright 2011-2018 The OpenSSL Project Authors. All Rights Reserved. |
12fb8c3d RS |
3 | * |
4 | * Licensed under the OpenSSL license (the "License"). You may not use | |
5 | * this file except in compliance with the License. You can obtain a copy | |
6 | * in the file LICENSE in the source distribution or at | |
7 | * https://www.openssl.org/source/license.html | |
8 | */ | |
9 | ||
10 | #include <string.h> | |
11 | #include <openssl/crypto.h> | |
12 | #include <openssl/err.h> | |
13 | #include <openssl/rand.h> | |
14 | #include "rand_lcl.h" | |
0b14a5b7 KR |
15 | #include "internal/thread_once.h" |
16 | #include "internal/rand_int.h" | |
12fb8c3d RS |
17 | |
18 | /* | |
19 | * Support framework for NIST SP 800-90A DRBG, AES-CTR mode. | |
75e2c877 RS |
20 | * The RAND_DRBG is OpenSSL's pointer to an instance of the DRBG. |
21 | * | |
12fb8c3d RS |
22 | * The OpenSSL model is to have new and free functions, and that new |
23 | * does all initialization. That is not the NIST model, which has | |
24 | * instantiation and un-instantiate, and re-use within a new/free | |
25 | * lifecycle. (No doubt this comes from the desire to support hardware | |
26 | * DRBG, where allocation of resources on something like an HSM is | |
27 | * a much bigger deal than just re-setting an allocated resource.) | |
12fb8c3d RS |
28 | */ |
29 | ||
a93ba405 DMSP |
30 | /* |
31 | * THE THREE SHARED DRBGs | |
32 | * | |
33 | * There are three shared DRBGs (master, public and private), which are | |
34 | * accessed concurrently by all threads. | |
35 | * | |
36 | * THE MASTER DRBG | |
37 | * | |
38 | * Not used directly by the application, only for reseeding the two other | |
39 | * DRBGs. It reseeds itself by pulling either randomness from os entropy | |
40 | * sources or by consuming randomnes which was added by RAND_add() | |
41 | */ | |
933033b6 | 42 | static RAND_DRBG *drbg_master; |
a93ba405 DMSP |
43 | /* |
44 | * THE PUBLIC DRBG | |
45 | * | |
46 | * Used by default for generating random bytes using RAND_bytes(). | |
47 | */ | |
933033b6 | 48 | static RAND_DRBG *drbg_public; |
a93ba405 DMSP |
49 | /* |
50 | * THE PRIVATE DRBG | |
51 | * | |
52 | * Used by default for generating private keys using RAND_priv_bytes() | |
53 | */ | |
933033b6 | 54 | static RAND_DRBG *drbg_private; |
a93ba405 DMSP |
55 | /*+ |
56 | * DRBG HIERARCHY | |
57 | * | |
58 | * In addition there are DRBGs, which are not shared, but used only by a | |
59 | * single thread at every time, for example the DRBGs which are owned by | |
60 | * an SSL context. All DRBGs are organized in a hierarchical fashion | |
61 | * with the <master> DRBG as root. | |
62 | * | |
63 | * This gives the following overall picture: | |
64 | * | |
65 | * <os entropy sources> | |
66 | * | | |
67 | * RAND_add() ==> <master> \ | |
68 | * / \ | shared DRBGs (with locking) | |
69 | * <public> <private> / | |
70 | * | | |
71 | * <ssl> owned by an SSL context | |
72 | * | |
73 | * AUTOMATIC RESEEDING | |
74 | * | |
08a65d96 DMSP |
75 | * Before satisfying a generate request, a DRBG reseeds itself automatically, |
76 | * if one of the following two conditions holds: | |
77 | * | |
78 | * - the number of generate requests since the last reseeding exceeds a | |
79 | * certain threshold, the so called |reseed_interval|. This behaviour | |
80 | * can be disabled by setting the |reseed_interval| to 0. | |
81 | * | |
82 | * - the time elapsed since the last reseeding exceeds a certain time | |
83 | * interval, the so called |reseed_time_interval|. This behaviour | |
84 | * can be disabled by setting the |reseed_time_interval| to 0. | |
a93ba405 DMSP |
85 | * |
86 | * MANUAL RESEEDING | |
87 | * | |
08a65d96 DMSP |
88 | * For the three shared DRBGs (and only for these) there is another way to |
89 | * reseed them manually by calling RAND_seed() (or RAND_add() with a positive | |
a93ba405 | 90 | * |randomness| argument). This will immediately reseed the <master> DRBG. |
08a65d96 DMSP |
91 | * The <public> and <private> DRBG will detect this on their next generate |
92 | * call and reseed, pulling randomness from <master>. | |
a93ba405 DMSP |
93 | */ |
94 | ||
95 | ||
96 | /* NIST SP 800-90A DRBG recommends the use of a personalization string. */ | |
97 | static const char ossl_pers_string[] = "OpenSSL NIST SP 800-90A DRBG"; | |
98 | ||
c16de9d8 DMSP |
99 | static CRYPTO_ONCE rand_drbg_init = CRYPTO_ONCE_STATIC_INIT; |
100 | ||
63ab5ea1 | 101 | static RAND_DRBG *drbg_setup(RAND_DRBG *parent); |
933033b6 | 102 | static void drbg_cleanup(RAND_DRBG *drbg); |
0b14a5b7 | 103 | |
12fb8c3d | 104 | /* |
75e2c877 | 105 | * Set/initialize |drbg| to be of type |nid|, with optional |flags|. |
efb8128a DMSP |
106 | * |
107 | * Returns 1 on success, 0 on failure. | |
12fb8c3d | 108 | */ |
75e2c877 | 109 | int RAND_DRBG_set(RAND_DRBG *drbg, int nid, unsigned int flags) |
12fb8c3d RS |
110 | { |
111 | int ret = 1; | |
112 | ||
75e2c877 RS |
113 | drbg->state = DRBG_UNINITIALISED; |
114 | drbg->flags = flags; | |
115 | drbg->nid = nid; | |
12fb8c3d RS |
116 | |
117 | switch (nid) { | |
118 | default: | |
119 | RANDerr(RAND_F_RAND_DRBG_SET, RAND_R_UNSUPPORTED_DRBG_TYPE); | |
efb8128a | 120 | return 0; |
12fb8c3d RS |
121 | case 0: |
122 | /* Uninitialized; that's okay. */ | |
123 | return 1; | |
124 | case NID_aes_128_ctr: | |
125 | case NID_aes_192_ctr: | |
126 | case NID_aes_256_ctr: | |
8212d505 | 127 | ret = drbg_ctr_init(drbg); |
12fb8c3d RS |
128 | break; |
129 | } | |
130 | ||
efb8128a | 131 | if (ret == 0) |
12fb8c3d RS |
132 | RANDerr(RAND_F_RAND_DRBG_SET, RAND_R_ERROR_INITIALISING_DRBG); |
133 | return ret; | |
134 | } | |
135 | ||
136 | /* | |
137 | * Allocate memory and initialize a new DRBG. The |parent|, if not | |
75e2c877 | 138 | * NULL, will be used to auto-seed this RAND_DRBG as needed. |
a93ba405 DMSP |
139 | * |
140 | * Returns a pointer to the new DRBG instance on success, NULL on failure. | |
12fb8c3d | 141 | */ |
75e2c877 | 142 | RAND_DRBG *RAND_DRBG_new(int type, unsigned int flags, RAND_DRBG *parent) |
12fb8c3d | 143 | { |
75e2c877 | 144 | RAND_DRBG *drbg = OPENSSL_zalloc(sizeof(*drbg)); |
12fb8c3d | 145 | |
9d951a78 | 146 | if (drbg == NULL) { |
12fb8c3d | 147 | RANDerr(RAND_F_RAND_DRBG_NEW, ERR_R_MALLOC_FAILURE); |
75e2c877 | 148 | goto err; |
12fb8c3d | 149 | } |
a35f607c | 150 | drbg->fork_count = rand_fork_count; |
75e2c877 | 151 | drbg->parent = parent; |
efb8128a | 152 | if (RAND_DRBG_set(drbg, type, flags) == 0) |
75e2c877 RS |
153 | goto err; |
154 | ||
a93ba405 DMSP |
155 | if (!RAND_DRBG_set_callbacks(drbg, rand_drbg_get_entropy, |
156 | rand_drbg_cleanup_entropy, | |
157 | NULL, NULL)) | |
158 | goto err; | |
75e2c877 RS |
159 | |
160 | return drbg; | |
161 | ||
162 | err: | |
75e2c877 RS |
163 | OPENSSL_free(drbg); |
164 | return NULL; | |
12fb8c3d RS |
165 | } |
166 | ||
167 | /* | |
75e2c877 | 168 | * Uninstantiate |drbg| and free all memory. |
12fb8c3d | 169 | */ |
75e2c877 | 170 | void RAND_DRBG_free(RAND_DRBG *drbg) |
12fb8c3d | 171 | { |
c16de9d8 | 172 | if (drbg == NULL) |
12fb8c3d RS |
173 | return; |
174 | ||
8212d505 DMSP |
175 | if (drbg->meth != NULL) |
176 | drbg->meth->uninstantiate(drbg); | |
75e2c877 RS |
177 | CRYPTO_free_ex_data(CRYPTO_EX_INDEX_DRBG, drbg, &drbg->ex_data); |
178 | OPENSSL_clear_free(drbg, sizeof(*drbg)); | |
12fb8c3d RS |
179 | } |
180 | ||
181 | /* | |
75e2c877 | 182 | * Instantiate |drbg|, after it has been initialized. Use |pers| and |
12fb8c3d | 183 | * |perslen| as prediction-resistance input. |
2139145b BK |
184 | * |
185 | * Requires that drbg->lock is already locked for write, if non-null. | |
efb8128a DMSP |
186 | * |
187 | * Returns 1 on success, 0 on failure. | |
12fb8c3d | 188 | */ |
75e2c877 | 189 | int RAND_DRBG_instantiate(RAND_DRBG *drbg, |
12fb8c3d RS |
190 | const unsigned char *pers, size_t perslen) |
191 | { | |
12fb8c3d | 192 | unsigned char *nonce = NULL, *entropy = NULL; |
aa048aef | 193 | size_t noncelen = 0, entropylen = 0; |
12fb8c3d | 194 | |
aa048aef | 195 | if (perslen > drbg->max_perslen) { |
75e2c877 RS |
196 | RANDerr(RAND_F_RAND_DRBG_INSTANTIATE, |
197 | RAND_R_PERSONALISATION_STRING_TOO_LONG); | |
12fb8c3d RS |
198 | goto end; |
199 | } | |
8212d505 DMSP |
200 | |
201 | if (drbg->meth == NULL) | |
202 | { | |
203 | RANDerr(RAND_F_RAND_DRBG_INSTANTIATE, | |
204 | RAND_R_NO_DRBG_IMPLEMENTATION_SELECTED); | |
205 | goto end; | |
206 | } | |
207 | ||
75e2c877 RS |
208 | if (drbg->state != DRBG_UNINITIALISED) { |
209 | RANDerr(RAND_F_RAND_DRBG_INSTANTIATE, | |
210 | drbg->state == DRBG_ERROR ? RAND_R_IN_ERROR_STATE | |
211 | : RAND_R_ALREADY_INSTANTIATED); | |
12fb8c3d RS |
212 | goto end; |
213 | } | |
214 | ||
75e2c877 RS |
215 | drbg->state = DRBG_ERROR; |
216 | if (drbg->get_entropy != NULL) | |
aa048aef DMSP |
217 | entropylen = drbg->get_entropy(drbg, &entropy, drbg->strength, |
218 | drbg->min_entropylen, drbg->max_entropylen); | |
c16de9d8 DMSP |
219 | if (entropylen < drbg->min_entropylen |
220 | || entropylen > drbg->max_entropylen) { | |
75e2c877 | 221 | RANDerr(RAND_F_RAND_DRBG_INSTANTIATE, RAND_R_ERROR_RETRIEVING_ENTROPY); |
12fb8c3d RS |
222 | goto end; |
223 | } | |
224 | ||
aa048aef | 225 | if (drbg->max_noncelen > 0 && drbg->get_nonce != NULL) { |
75e2c877 | 226 | noncelen = drbg->get_nonce(drbg, &nonce, drbg->strength / 2, |
aa048aef DMSP |
227 | drbg->min_noncelen, drbg->max_noncelen); |
228 | if (noncelen < drbg->min_noncelen || noncelen > drbg->max_noncelen) { | |
c16de9d8 DMSP |
229 | RANDerr(RAND_F_RAND_DRBG_INSTANTIATE, |
230 | RAND_R_ERROR_RETRIEVING_NONCE); | |
12fb8c3d RS |
231 | goto end; |
232 | } | |
233 | } | |
234 | ||
8212d505 | 235 | if (!drbg->meth->instantiate(drbg, entropy, entropylen, |
12fb8c3d | 236 | nonce, noncelen, pers, perslen)) { |
75e2c877 | 237 | RANDerr(RAND_F_RAND_DRBG_INSTANTIATE, RAND_R_ERROR_INSTANTIATING_DRBG); |
12fb8c3d RS |
238 | goto end; |
239 | } | |
240 | ||
75e2c877 | 241 | drbg->state = DRBG_READY; |
a93ba405 | 242 | drbg->generate_counter = 0; |
08a65d96 | 243 | drbg->reseed_time = time(NULL); |
a93ba405 DMSP |
244 | if (drbg->reseed_counter > 0) { |
245 | if (drbg->parent == NULL) | |
246 | drbg->reseed_counter++; | |
247 | else | |
248 | drbg->reseed_counter = drbg->parent->reseed_counter; | |
249 | } | |
12fb8c3d RS |
250 | |
251 | end: | |
75e2c877 | 252 | if (entropy != NULL && drbg->cleanup_entropy != NULL) |
6969a3f4 | 253 | drbg->cleanup_entropy(drbg, entropy, entropylen); |
75e2c877 | 254 | if (nonce != NULL && drbg->cleanup_nonce!= NULL ) |
6969a3f4 | 255 | drbg->cleanup_nonce(drbg, nonce, noncelen); |
c16de9d8 DMSP |
256 | if (drbg->pool != NULL) { |
257 | if (drbg->state == DRBG_READY) { | |
258 | RANDerr(RAND_F_RAND_DRBG_INSTANTIATE, | |
259 | RAND_R_ERROR_ENTROPY_POOL_WAS_IGNORED); | |
260 | drbg->state = DRBG_ERROR; | |
261 | } | |
262 | RAND_POOL_free(drbg->pool); | |
263 | drbg->pool = NULL; | |
264 | } | |
75e2c877 | 265 | if (drbg->state == DRBG_READY) |
12fb8c3d | 266 | return 1; |
12fb8c3d RS |
267 | return 0; |
268 | } | |
269 | ||
270 | /* | |
75e2c877 | 271 | * Uninstantiate |drbg|. Must be instantiated before it can be used. |
2139145b BK |
272 | * |
273 | * Requires that drbg->lock is already locked for write, if non-null. | |
efb8128a DMSP |
274 | * |
275 | * Returns 1 on success, 0 on failure. | |
12fb8c3d | 276 | */ |
75e2c877 | 277 | int RAND_DRBG_uninstantiate(RAND_DRBG *drbg) |
12fb8c3d | 278 | { |
8212d505 DMSP |
279 | if (drbg->meth == NULL) |
280 | { | |
281 | RANDerr(RAND_F_RAND_DRBG_UNINSTANTIATE, | |
282 | RAND_R_NO_DRBG_IMPLEMENTATION_SELECTED); | |
283 | return 0; | |
284 | } | |
285 | ||
efb8128a DMSP |
286 | /* Clear the entire drbg->ctr struct, then reset some important |
287 | * members of the drbg->ctr struct (e.g. keysize, df_ks) to their | |
288 | * initial values. | |
289 | */ | |
8212d505 | 290 | drbg->meth->uninstantiate(drbg); |
efb8128a | 291 | return RAND_DRBG_set(drbg, drbg->nid, drbg->flags); |
12fb8c3d RS |
292 | } |
293 | ||
294 | /* | |
c16de9d8 | 295 | * Reseed |drbg|, mixing in the specified data |
2139145b BK |
296 | * |
297 | * Requires that drbg->lock is already locked for write, if non-null. | |
efb8128a DMSP |
298 | * |
299 | * Returns 1 on success, 0 on failure. | |
12fb8c3d | 300 | */ |
75e2c877 | 301 | int RAND_DRBG_reseed(RAND_DRBG *drbg, |
12fb8c3d RS |
302 | const unsigned char *adin, size_t adinlen) |
303 | { | |
304 | unsigned char *entropy = NULL; | |
aa048aef | 305 | size_t entropylen = 0; |
75e2c877 RS |
306 | |
307 | if (drbg->state == DRBG_ERROR) { | |
308 | RANDerr(RAND_F_RAND_DRBG_RESEED, RAND_R_IN_ERROR_STATE); | |
309 | return 0; | |
310 | } | |
311 | if (drbg->state == DRBG_UNINITIALISED) { | |
312 | RANDerr(RAND_F_RAND_DRBG_RESEED, RAND_R_NOT_INSTANTIATED); | |
313 | return 0; | |
12fb8c3d RS |
314 | } |
315 | ||
316 | if (adin == NULL) | |
317 | adinlen = 0; | |
aa048aef | 318 | else if (adinlen > drbg->max_adinlen) { |
75e2c877 RS |
319 | RANDerr(RAND_F_RAND_DRBG_RESEED, RAND_R_ADDITIONAL_INPUT_TOO_LONG); |
320 | return 0; | |
12fb8c3d RS |
321 | } |
322 | ||
75e2c877 RS |
323 | drbg->state = DRBG_ERROR; |
324 | if (drbg->get_entropy != NULL) | |
aa048aef DMSP |
325 | entropylen = drbg->get_entropy(drbg, &entropy, drbg->strength, |
326 | drbg->min_entropylen, drbg->max_entropylen); | |
c16de9d8 DMSP |
327 | if (entropylen < drbg->min_entropylen |
328 | || entropylen > drbg->max_entropylen) { | |
75e2c877 | 329 | RANDerr(RAND_F_RAND_DRBG_RESEED, RAND_R_ERROR_RETRIEVING_ENTROPY); |
12fb8c3d RS |
330 | goto end; |
331 | } | |
332 | ||
8212d505 | 333 | if (!drbg->meth->reseed(drbg, entropy, entropylen, adin, adinlen)) |
12fb8c3d | 334 | goto end; |
a93ba405 | 335 | |
75e2c877 | 336 | drbg->state = DRBG_READY; |
a93ba405 | 337 | drbg->generate_counter = 0; |
08a65d96 | 338 | drbg->reseed_time = time(NULL); |
a93ba405 DMSP |
339 | if (drbg->reseed_counter > 0) { |
340 | if (drbg->parent == NULL) | |
341 | drbg->reseed_counter++; | |
342 | else | |
343 | drbg->reseed_counter = drbg->parent->reseed_counter; | |
344 | } | |
12fb8c3d RS |
345 | |
346 | end: | |
75e2c877 | 347 | if (entropy != NULL && drbg->cleanup_entropy != NULL) |
6969a3f4 | 348 | drbg->cleanup_entropy(drbg, entropy, entropylen); |
75e2c877 | 349 | if (drbg->state == DRBG_READY) |
12fb8c3d | 350 | return 1; |
12fb8c3d RS |
351 | return 0; |
352 | } | |
353 | ||
c16de9d8 DMSP |
354 | /* |
355 | * Restart |drbg|, using the specified entropy or additional input | |
356 | * | |
357 | * Tries its best to get the drbg instantiated by all means, | |
358 | * regardless of its current state. | |
359 | * | |
360 | * Optionally, a |buffer| of |len| random bytes can be passed, | |
361 | * which is assumed to contain at least |entropy| bits of entropy. | |
362 | * | |
363 | * If |entropy| > 0, the buffer content is used as entropy input. | |
364 | * | |
365 | * If |entropy| == 0, the buffer content is used as additional input | |
366 | * | |
367 | * Returns 1 on success, 0 on failure. | |
368 | * | |
369 | * This function is used internally only. | |
370 | */ | |
371 | int rand_drbg_restart(RAND_DRBG *drbg, | |
372 | const unsigned char *buffer, size_t len, size_t entropy) | |
373 | { | |
374 | int reseeded = 0; | |
375 | const unsigned char *adin = NULL; | |
376 | size_t adinlen = 0; | |
377 | ||
378 | if (drbg->pool != NULL) { | |
379 | RANDerr(RAND_F_RAND_DRBG_RESTART, ERR_R_INTERNAL_ERROR); | |
380 | RAND_POOL_free(drbg->pool); | |
381 | drbg->pool = NULL; | |
382 | } | |
383 | ||
384 | if (buffer != NULL) { | |
385 | if (entropy > 0) { | |
386 | if (drbg->max_entropylen < len) { | |
387 | RANDerr(RAND_F_RAND_DRBG_RESTART, | |
388 | RAND_R_ENTROPY_INPUT_TOO_LONG); | |
389 | return 0; | |
390 | } | |
391 | ||
392 | if (entropy > 8 * len) { | |
393 | RANDerr(RAND_F_RAND_DRBG_RESTART, RAND_R_ENTROPY_OUT_OF_RANGE); | |
394 | return 0; | |
395 | } | |
396 | ||
397 | /* will be picked up by the rand_drbg_get_entropy() callback */ | |
398 | drbg->pool = RAND_POOL_new(entropy, len, len); | |
399 | if (drbg->pool == NULL) | |
400 | return 0; | |
401 | ||
402 | RAND_POOL_add(drbg->pool, buffer, len, entropy); | |
403 | } else { | |
404 | if (drbg->max_adinlen < len) { | |
405 | RANDerr(RAND_F_RAND_DRBG_RESTART, | |
406 | RAND_R_ADDITIONAL_INPUT_TOO_LONG); | |
407 | return 0; | |
408 | } | |
409 | adin = buffer; | |
410 | adinlen = len; | |
411 | } | |
412 | } | |
413 | ||
414 | /* repair error state */ | |
efb8128a | 415 | if (drbg->state == DRBG_ERROR) |
c16de9d8 DMSP |
416 | RAND_DRBG_uninstantiate(drbg); |
417 | ||
418 | /* repair uninitialized state */ | |
419 | if (drbg->state == DRBG_UNINITIALISED) { | |
a93ba405 DMSP |
420 | /* reinstantiate drbg */ |
421 | RAND_DRBG_instantiate(drbg, | |
422 | (const unsigned char *) ossl_pers_string, | |
423 | sizeof(ossl_pers_string) - 1); | |
c16de9d8 DMSP |
424 | /* already reseeded. prevent second reseeding below */ |
425 | reseeded = (drbg->state == DRBG_READY); | |
426 | } | |
427 | ||
428 | /* refresh current state if entropy or additional input has been provided */ | |
429 | if (drbg->state == DRBG_READY) { | |
430 | if (adin != NULL) { | |
431 | /* | |
432 | * mix in additional input without reseeding | |
433 | * | |
434 | * Similar to RAND_DRBG_reseed(), but the provided additional | |
435 | * data |adin| is mixed into the current state without pulling | |
436 | * entropy from the trusted entropy source using get_entropy(). | |
437 | * This is not a reseeding in the strict sense of NIST SP 800-90A. | |
438 | */ | |
8212d505 | 439 | drbg->meth->reseed(drbg, adin, adinlen, NULL, 0); |
c16de9d8 DMSP |
440 | } else if (reseeded == 0) { |
441 | /* do a full reseeding if it has not been done yet above */ | |
442 | RAND_DRBG_reseed(drbg, NULL, 0); | |
443 | } | |
444 | } | |
445 | ||
446 | /* check whether a given entropy pool was cleared properly during reseed */ | |
447 | if (drbg->pool != NULL) { | |
448 | drbg->state = DRBG_ERROR; | |
449 | RANDerr(RAND_F_RAND_DRBG_RESTART, ERR_R_INTERNAL_ERROR); | |
450 | RAND_POOL_free(drbg->pool); | |
451 | drbg->pool = NULL; | |
452 | return 0; | |
453 | } | |
454 | ||
455 | return drbg->state == DRBG_READY; | |
456 | } | |
457 | ||
12fb8c3d RS |
458 | /* |
459 | * Generate |outlen| bytes into the buffer at |out|. Reseed if we need | |
460 | * to or if |prediction_resistance| is set. Additional input can be | |
461 | * sent in |adin| and |adinlen|. | |
c16de9d8 | 462 | * |
2139145b BK |
463 | * Requires that drbg->lock is already locked for write, if non-null. |
464 | * | |
c16de9d8 DMSP |
465 | * Returns 1 on success, 0 on failure. |
466 | * | |
12fb8c3d | 467 | */ |
75e2c877 | 468 | int RAND_DRBG_generate(RAND_DRBG *drbg, unsigned char *out, size_t outlen, |
12fb8c3d RS |
469 | int prediction_resistance, |
470 | const unsigned char *adin, size_t adinlen) | |
471 | { | |
e0b625f9 DMSP |
472 | int reseed_required = 0; |
473 | ||
c16de9d8 DMSP |
474 | if (drbg->state != DRBG_READY) { |
475 | /* try to recover from previous errors */ | |
476 | rand_drbg_restart(drbg, NULL, 0, 0); | |
477 | ||
478 | if (drbg->state == DRBG_ERROR) { | |
479 | RANDerr(RAND_F_RAND_DRBG_GENERATE, RAND_R_IN_ERROR_STATE); | |
480 | return 0; | |
481 | } | |
482 | if (drbg->state == DRBG_UNINITIALISED) { | |
483 | RANDerr(RAND_F_RAND_DRBG_GENERATE, RAND_R_NOT_INSTANTIATED); | |
484 | return 0; | |
485 | } | |
12fb8c3d | 486 | } |
c16de9d8 | 487 | |
75e2c877 RS |
488 | if (outlen > drbg->max_request) { |
489 | RANDerr(RAND_F_RAND_DRBG_GENERATE, RAND_R_REQUEST_TOO_LARGE_FOR_DRBG); | |
490 | return 0; | |
491 | } | |
aa048aef | 492 | if (adinlen > drbg->max_adinlen) { |
75e2c877 RS |
493 | RANDerr(RAND_F_RAND_DRBG_GENERATE, RAND_R_ADDITIONAL_INPUT_TOO_LONG); |
494 | return 0; | |
12fb8c3d RS |
495 | } |
496 | ||
a35f607c RS |
497 | if (drbg->fork_count != rand_fork_count) { |
498 | drbg->fork_count = rand_fork_count; | |
e0b625f9 | 499 | reseed_required = 1; |
a35f607c RS |
500 | } |
501 | ||
a93ba405 DMSP |
502 | if (drbg->reseed_interval > 0) { |
503 | if (drbg->generate_counter >= drbg->reseed_interval) | |
504 | reseed_required = 1; | |
505 | } | |
08a65d96 DMSP |
506 | if (drbg->reseed_time_interval > 0) { |
507 | time_t now = time(NULL); | |
508 | if (now < drbg->reseed_time | |
509 | || now - drbg->reseed_time >= drbg->reseed_time_interval) | |
510 | reseed_required = 1; | |
511 | } | |
a93ba405 DMSP |
512 | if (drbg->reseed_counter > 0 && drbg->parent != NULL) { |
513 | if (drbg->reseed_counter != drbg->parent->reseed_counter) | |
514 | reseed_required = 1; | |
515 | } | |
12fb8c3d | 516 | |
e0b625f9 | 517 | if (reseed_required || prediction_resistance) { |
75e2c877 RS |
518 | if (!RAND_DRBG_reseed(drbg, adin, adinlen)) { |
519 | RANDerr(RAND_F_RAND_DRBG_GENERATE, RAND_R_RESEED_ERROR); | |
520 | return 0; | |
12fb8c3d RS |
521 | } |
522 | adin = NULL; | |
523 | adinlen = 0; | |
524 | } | |
525 | ||
8212d505 | 526 | if (!drbg->meth->generate(drbg, out, outlen, adin, adinlen)) { |
75e2c877 RS |
527 | drbg->state = DRBG_ERROR; |
528 | RANDerr(RAND_F_RAND_DRBG_GENERATE, RAND_R_GENERATE_ERROR); | |
529 | return 0; | |
12fb8c3d | 530 | } |
75e2c877 | 531 | |
a93ba405 | 532 | drbg->generate_counter++; |
e0b625f9 | 533 | |
12fb8c3d | 534 | return 1; |
12fb8c3d RS |
535 | } |
536 | ||
20928ff6 KR |
537 | /* |
538 | * Generates |outlen| random bytes and stores them in |out|. It will | |
539 | * using the given |drbg| to generate the bytes. | |
540 | * | |
541 | * Requires that drbg->lock is already locked for write, if non-null. | |
542 | * | |
543 | * Returns 1 on success 0 on failure. | |
544 | */ | |
545 | int RAND_DRBG_bytes(RAND_DRBG *drbg, unsigned char *out, size_t outlen) | |
546 | { | |
547 | unsigned char *additional = NULL; | |
548 | size_t additional_len; | |
1648338b | 549 | size_t chunk; |
20928ff6 KR |
550 | size_t ret; |
551 | ||
552 | additional_len = rand_drbg_get_additional_data(&additional, drbg->max_adinlen); | |
1648338b DMSP |
553 | |
554 | for ( ; outlen > 0; outlen -= chunk, out += chunk) { | |
555 | chunk = outlen; | |
556 | if (chunk > drbg->max_request) | |
557 | chunk = drbg->max_request; | |
558 | ret = RAND_DRBG_generate(drbg, out, chunk, 0, additional, additional_len); | |
559 | if (!ret) | |
560 | goto err; | |
561 | } | |
562 | ret = 1; | |
563 | ||
564 | err: | |
20928ff6 KR |
565 | if (additional_len != 0) |
566 | OPENSSL_secure_clear_free(additional, additional_len); | |
567 | ||
568 | return ret; | |
569 | } | |
570 | ||
12fb8c3d | 571 | /* |
c16de9d8 DMSP |
572 | * Set the RAND_DRBG callbacks for obtaining entropy and nonce. |
573 | * | |
574 | * In the following, the signature and the semantics of the | |
575 | * get_entropy() and cleanup_entropy() callbacks are explained. | |
576 | * | |
577 | * GET_ENTROPY | |
578 | * | |
579 | * size_t get_entropy(RAND_DRBG *ctx, | |
580 | * unsigned char **pout, | |
581 | * int entropy, | |
582 | * size_t min_len, size_t max_len); | |
583 | * | |
584 | * This is a request to allocate and fill a buffer of size | |
585 | * |min_len| <= size <= |max_len| (in bytes) which contains | |
586 | * at least |entropy| bits of randomness. The buffer's address is | |
587 | * to be returned in |*pout| and the number of collected | |
588 | * randomness bytes (which may be less than the allocated size | |
589 | * of the buffer) as return value. | |
590 | * | |
591 | * If the callback fails to acquire at least |entropy| bits of | |
592 | * randomness, it shall return a buffer length of 0. | |
593 | * | |
594 | * CLEANUP_ENTROPY | |
595 | * | |
596 | * void cleanup_entropy(RAND_DRBG *ctx, | |
597 | * unsigned char *out, size_t outlen); | |
598 | * | |
599 | * A request to clear and free the buffer allocated by get_entropy(). | |
600 | * The values |out| and |outlen| are expected to be the random buffer's | |
601 | * address and length, as returned by the get_entropy() callback. | |
602 | * | |
603 | * GET_NONCE, CLEANUP_NONCE | |
604 | * | |
605 | * Signature and semantics of the get_nonce() and cleanup_nonce() | |
606 | * callbacks are analogous to get_entropy() and cleanup_entropy(). | |
607 | * Currently, the nonce is used only for the known answer tests. | |
12fb8c3d | 608 | */ |
75e2c877 | 609 | int RAND_DRBG_set_callbacks(RAND_DRBG *drbg, |
c16de9d8 DMSP |
610 | RAND_DRBG_get_entropy_fn get_entropy, |
611 | RAND_DRBG_cleanup_entropy_fn cleanup_entropy, | |
612 | RAND_DRBG_get_nonce_fn get_nonce, | |
613 | RAND_DRBG_cleanup_nonce_fn cleanup_nonce) | |
12fb8c3d | 614 | { |
75e2c877 | 615 | if (drbg->state != DRBG_UNINITIALISED) |
12fb8c3d | 616 | return 0; |
c16de9d8 DMSP |
617 | drbg->get_entropy = get_entropy; |
618 | drbg->cleanup_entropy = cleanup_entropy; | |
619 | drbg->get_nonce = get_nonce; | |
620 | drbg->cleanup_nonce = cleanup_nonce; | |
12fb8c3d RS |
621 | return 1; |
622 | } | |
623 | ||
624 | /* | |
75e2c877 | 625 | * Set the reseed interval. |
a93ba405 DMSP |
626 | * |
627 | * The drbg will reseed automatically whenever the number of generate | |
628 | * requests exceeds the given reseed interval. If the reseed interval | |
08a65d96 | 629 | * is 0, then this feature is disabled. |
a93ba405 DMSP |
630 | * |
631 | * Returns 1 on success, 0 on failure. | |
12fb8c3d | 632 | */ |
a93ba405 | 633 | int RAND_DRBG_set_reseed_interval(RAND_DRBG *drbg, unsigned int interval) |
12fb8c3d | 634 | { |
a93ba405 | 635 | if (interval > MAX_RESEED_INTERVAL) |
4c75ee85 | 636 | return 0; |
75e2c877 | 637 | drbg->reseed_interval = interval; |
4c75ee85 | 638 | return 1; |
12fb8c3d RS |
639 | } |
640 | ||
08a65d96 DMSP |
641 | /* |
642 | * Set the reseed time interval. | |
643 | * | |
644 | * The drbg will reseed automatically whenever the time elapsed since | |
645 | * the last reseeding exceeds the given reseed time interval. For safety, | |
646 | * a reseeding will also occur if the clock has been reset to a smaller | |
647 | * value. | |
648 | * | |
649 | * Returns 1 on success, 0 on failure. | |
650 | */ | |
651 | int RAND_DRBG_set_reseed_time_interval(RAND_DRBG *drbg, time_t interval) | |
652 | { | |
653 | if (interval > MAX_RESEED_TIME_INTERVAL) | |
654 | return 0; | |
655 | drbg->reseed_time_interval = interval; | |
656 | return 1; | |
657 | } | |
658 | ||
12fb8c3d RS |
659 | /* |
660 | * Get and set the EXDATA | |
661 | */ | |
75e2c877 RS |
662 | int RAND_DRBG_set_ex_data(RAND_DRBG *drbg, int idx, void *arg) |
663 | { | |
664 | return CRYPTO_set_ex_data(&drbg->ex_data, idx, arg); | |
665 | } | |
666 | ||
667 | void *RAND_DRBG_get_ex_data(const RAND_DRBG *drbg, int idx) | |
668 | { | |
669 | return CRYPTO_get_ex_data(&drbg->ex_data, idx); | |
670 | } | |
671 | ||
672 | ||
673 | /* | |
674 | * The following functions provide a RAND_METHOD that works on the | |
675 | * global DRBG. They lock. | |
676 | */ | |
677 | ||
0b14a5b7 | 678 | /* |
933033b6 DMSP |
679 | * Allocates a new global DRBG on the secure heap (if enabled) and |
680 | * initializes it with default settings. | |
a93ba405 DMSP |
681 | * |
682 | * Returns a pointer to the new DRBG instance on success, NULL on failure. | |
0b14a5b7 | 683 | */ |
63ab5ea1 | 684 | static RAND_DRBG *drbg_setup(RAND_DRBG *parent) |
0b14a5b7 | 685 | { |
933033b6 | 686 | RAND_DRBG *drbg; |
0b14a5b7 | 687 | |
933033b6 DMSP |
688 | drbg = OPENSSL_secure_zalloc(sizeof(RAND_DRBG)); |
689 | if (drbg == NULL) | |
690 | return NULL; | |
691 | ||
63ab5ea1 | 692 | drbg->lock = CRYPTO_THREAD_lock_new(); |
a93ba405 DMSP |
693 | if (drbg->lock == NULL) { |
694 | RANDerr(RAND_F_DRBG_SETUP, RAND_R_FAILED_TO_CREATE_LOCK); | |
933033b6 | 695 | goto err; |
c16de9d8 DMSP |
696 | } |
697 | ||
933033b6 DMSP |
698 | if (RAND_DRBG_set(drbg, |
699 | RAND_DRBG_NID, RAND_DRBG_FLAG_CTR_USE_DF) != 1) | |
700 | goto err; | |
701 | if (RAND_DRBG_set_callbacks(drbg, rand_drbg_get_entropy, | |
702 | rand_drbg_cleanup_entropy, NULL, NULL) != 1) | |
703 | goto err; | |
a93ba405 | 704 | |
08a65d96 | 705 | if (parent == NULL) { |
a93ba405 | 706 | drbg->reseed_interval = MASTER_RESEED_INTERVAL; |
08a65d96 DMSP |
707 | drbg->reseed_time_interval = MASTER_RESEED_TIME_INTERVAL; |
708 | } else { | |
a93ba405 DMSP |
709 | drbg->parent = parent; |
710 | drbg->reseed_interval = SLAVE_RESEED_INTERVAL; | |
08a65d96 | 711 | drbg->reseed_time_interval = SLAVE_RESEED_TIME_INTERVAL; |
a93ba405 DMSP |
712 | } |
713 | ||
714 | /* enable seed propagation */ | |
715 | drbg->reseed_counter = 1; | |
716 | ||
c16de9d8 DMSP |
717 | /* |
718 | * Ignore instantiation error so support just-in-time instantiation. | |
719 | * | |
720 | * The state of the drbg will be checked in RAND_DRBG_generate() and | |
721 | * an automatic recovery is attempted. | |
722 | */ | |
723 | RAND_DRBG_instantiate(drbg, | |
724 | (const unsigned char *) ossl_pers_string, | |
725 | sizeof(ossl_pers_string) - 1); | |
933033b6 DMSP |
726 | return drbg; |
727 | ||
728 | err: | |
729 | drbg_cleanup(drbg); | |
730 | return NULL; | |
0b14a5b7 KR |
731 | } |
732 | ||
733 | /* | |
734 | * Initialize the global DRBGs on first use. | |
735 | * Returns 1 on success, 0 on failure. | |
736 | */ | |
c16de9d8 | 737 | DEFINE_RUN_ONCE_STATIC(do_rand_drbg_init) |
0b14a5b7 | 738 | { |
39571fca DMSP |
739 | /* |
740 | * ensure that libcrypto is initialized, otherwise the | |
741 | * DRBG locks are not cleaned up properly | |
742 | */ | |
743 | if (!OPENSSL_init_crypto(0, NULL)) | |
744 | return 0; | |
745 | ||
63ab5ea1 BK |
746 | drbg_master = drbg_setup(NULL); |
747 | drbg_public = drbg_setup(drbg_master); | |
748 | drbg_private = drbg_setup(drbg_master); | |
0b14a5b7 | 749 | |
933033b6 DMSP |
750 | if (drbg_master == NULL || drbg_public == NULL || drbg_private == NULL) |
751 | return 0; | |
0b14a5b7 | 752 | |
933033b6 | 753 | return 1; |
0b14a5b7 KR |
754 | } |
755 | ||
c16de9d8 DMSP |
756 | /* Cleans up the given global DRBG */ |
757 | static void drbg_cleanup(RAND_DRBG *drbg) | |
0b14a5b7 | 758 | { |
933033b6 DMSP |
759 | if (drbg != NULL) { |
760 | RAND_DRBG_uninstantiate(drbg); | |
761 | CRYPTO_THREAD_lock_free(drbg->lock); | |
762 | OPENSSL_secure_clear_free(drbg, sizeof(RAND_DRBG)); | |
763 | } | |
0b14a5b7 KR |
764 | } |
765 | ||
766 | /* Clean up the global DRBGs before exit */ | |
c16de9d8 | 767 | void rand_drbg_cleanup_int(void) |
0b14a5b7 | 768 | { |
933033b6 DMSP |
769 | drbg_cleanup(drbg_private); |
770 | drbg_cleanup(drbg_public); | |
771 | drbg_cleanup(drbg_master); | |
772 | ||
773 | drbg_private = drbg_public = drbg_master = NULL; | |
0b14a5b7 KR |
774 | } |
775 | ||
c16de9d8 | 776 | /* Implements the default OpenSSL RAND_bytes() method */ |
75e2c877 RS |
777 | static int drbg_bytes(unsigned char *out, int count) |
778 | { | |
f61f62ea | 779 | int ret; |
a93ba405 | 780 | RAND_DRBG *drbg = RAND_DRBG_get0_public(); |
75e2c877 | 781 | |
0b14a5b7 KR |
782 | if (drbg == NULL) |
783 | return 0; | |
784 | ||
785 | CRYPTO_THREAD_write_lock(drbg->lock); | |
f61f62ea | 786 | ret = RAND_DRBG_bytes(drbg, out, count); |
0b14a5b7 | 787 | CRYPTO_THREAD_unlock(drbg->lock); |
f61f62ea | 788 | |
75e2c877 RS |
789 | return ret; |
790 | } | |
791 | ||
c16de9d8 | 792 | /* Implements the default OpenSSL RAND_add() method */ |
75e2c877 RS |
793 | static int drbg_add(const void *buf, int num, double randomness) |
794 | { | |
c16de9d8 | 795 | int ret = 0; |
a93ba405 | 796 | RAND_DRBG *drbg = RAND_DRBG_get0_master(); |
75e2c877 | 797 | |
c16de9d8 DMSP |
798 | if (drbg == NULL) |
799 | return 0; | |
75e2c877 | 800 | |
c16de9d8 DMSP |
801 | if (num < 0 || randomness < 0.0) |
802 | return 0; | |
75e2c877 | 803 | |
c16de9d8 DMSP |
804 | if (randomness > (double)drbg->max_entropylen) { |
805 | /* | |
806 | * The purpose of this check is to bound |randomness| by a | |
807 | * relatively small value in order to prevent an integer | |
808 | * overflow when multiplying by 8 in the rand_drbg_restart() | |
809 | * call below. | |
810 | */ | |
811 | return 0; | |
75e2c877 RS |
812 | } |
813 | ||
c16de9d8 DMSP |
814 | CRYPTO_THREAD_write_lock(drbg->lock); |
815 | ret = rand_drbg_restart(drbg, buf, | |
816 | (size_t)(unsigned int)num, | |
817 | (size_t)(8*randomness)); | |
818 | CRYPTO_THREAD_unlock(drbg->lock); | |
819 | ||
820 | return ret; | |
75e2c877 RS |
821 | } |
822 | ||
c16de9d8 | 823 | /* Implements the default OpenSSL RAND_seed() method */ |
75e2c877 RS |
824 | static int drbg_seed(const void *buf, int num) |
825 | { | |
826 | return drbg_add(buf, num, num); | |
827 | } | |
828 | ||
c16de9d8 | 829 | /* Implements the default OpenSSL RAND_status() method */ |
75e2c877 | 830 | static int drbg_status(void) |
12fb8c3d | 831 | { |
75e2c877 | 832 | int ret; |
a93ba405 | 833 | RAND_DRBG *drbg = RAND_DRBG_get0_master(); |
0b14a5b7 KR |
834 | |
835 | if (drbg == NULL) | |
836 | return 0; | |
75e2c877 | 837 | |
0b14a5b7 KR |
838 | CRYPTO_THREAD_write_lock(drbg->lock); |
839 | ret = drbg->state == DRBG_READY ? 1 : 0; | |
840 | CRYPTO_THREAD_unlock(drbg->lock); | |
75e2c877 | 841 | return ret; |
12fb8c3d RS |
842 | } |
843 | ||
0b14a5b7 | 844 | /* |
a93ba405 DMSP |
845 | * Get the master DRBG. |
846 | * Returns pointer to the DRBG on success, NULL on failure. | |
847 | * | |
848 | */ | |
849 | RAND_DRBG *RAND_DRBG_get0_master(void) | |
850 | { | |
851 | if (!RUN_ONCE(&rand_drbg_init, do_rand_drbg_init)) | |
852 | return NULL; | |
853 | ||
933033b6 | 854 | return drbg_master; |
a93ba405 DMSP |
855 | } |
856 | ||
857 | /* | |
858 | * Get the public DRBG. | |
0b14a5b7 KR |
859 | * Returns pointer to the DRBG on success, NULL on failure. |
860 | */ | |
a93ba405 | 861 | RAND_DRBG *RAND_DRBG_get0_public(void) |
0b14a5b7 | 862 | { |
c16de9d8 | 863 | if (!RUN_ONCE(&rand_drbg_init, do_rand_drbg_init)) |
0b14a5b7 KR |
864 | return NULL; |
865 | ||
933033b6 | 866 | return drbg_public; |
0b14a5b7 KR |
867 | } |
868 | ||
869 | /* | |
a93ba405 | 870 | * Get the private DRBG. |
0b14a5b7 KR |
871 | * Returns pointer to the DRBG on success, NULL on failure. |
872 | */ | |
a93ba405 | 873 | RAND_DRBG *RAND_DRBG_get0_private(void) |
0b14a5b7 | 874 | { |
c16de9d8 | 875 | if (!RUN_ONCE(&rand_drbg_init, do_rand_drbg_init)) |
0b14a5b7 KR |
876 | return NULL; |
877 | ||
933033b6 | 878 | return drbg_private; |
0b14a5b7 KR |
879 | } |
880 | ||
75e2c877 RS |
881 | RAND_METHOD rand_meth = { |
882 | drbg_seed, | |
883 | drbg_bytes, | |
ddc6a5c8 | 884 | NULL, |
75e2c877 RS |
885 | drbg_add, |
886 | drbg_bytes, | |
887 | drbg_status | |
888 | }; | |
889 | ||
890 | RAND_METHOD *RAND_OpenSSL(void) | |
12fb8c3d | 891 | { |
75e2c877 | 892 | return &rand_meth; |
12fb8c3d | 893 | } |