1 | /* |
2 | * Copyright 2011-2018 The OpenSSL Project Authors. All Rights Reserved. |
3 | * |
4 | * Licensed under the Apache License 2.0 (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_local.h" |
15 | #include "internal/thread_once.h" |
16 | #include "crypto/rand.h" |
17 | #include "crypto/cryptlib.h" |
18 | |
19 | /* |
20 | * Support framework for NIST SP 800-90A DRBG |
21 | * |
22 | * See manual page RAND_DRBG(7) for a general overview. |
23 | * |
24 | * The OpenSSL model is to have new and free functions, and that new |
25 | * does all initialization. That is not the NIST model, which has |
26 | * instantiation and un-instantiate, and re-use within a new/free |
27 | * lifecycle. (No doubt this comes from the desire to support hardware |
28 | * DRBG, where allocation of resources on something like an HSM is |
29 | * a much bigger deal than just re-setting an allocated resource.) |
30 | */ |
31 | |
32 | |
33 | typedef struct drbg_global_st { |
34 | /* |
35 | * The three shared DRBG instances |
36 | * |
37 | * There are three shared DRBG instances: <master>, <public>, and <private>. |
38 | */ |
39 | |
40 | /* |
41 | * The <master> DRBG |
42 | * |
43 | * Not used directly by the application, only for reseeding the two other |
44 | * DRBGs. It reseeds itself by pulling either randomness from os entropy |
45 | * sources or by consuming randomness which was added by RAND_add(). |
46 | * |
47 | * The <master> DRBG is a global instance which is accessed concurrently by |
48 | * all threads. The necessary locking is managed automatically by its child |
49 | * DRBG instances during reseeding. |
50 | */ |
51 | RAND_DRBG *master_drbg; |
52 | /* |
53 | * The <public> DRBG |
54 | * |
55 | * Used by default for generating random bytes using RAND_bytes(). |
56 | * |
57 | * The <public> DRBG is thread-local, i.e., there is one instance per |
58 | * thread. |
59 | */ |
60 | CRYPTO_THREAD_LOCAL public_drbg; |
61 | /* |
62 | * The <private> DRBG |
63 | * |
64 | * Used by default for generating private keys using RAND_priv_bytes() |
65 | * |
66 | * The <private> DRBG is thread-local, i.e., there is one instance per |
67 | * thread. |
68 | */ |
69 | CRYPTO_THREAD_LOCAL private_drbg; |
70 | } DRBG_GLOBAL; |
71 | |
72 | typedef struct drbg_nonce_global_st { |
73 | CRYPTO_RWLOCK *rand_nonce_lock; |
74 | int rand_nonce_count; |
75 | } DRBG_NONCE_GLOBAL; |
76 | |
77 | /* NIST SP 800-90A DRBG recommends the use of a personalization string. */ |
78 | static const char ossl_pers_string[] = DRBG_DEFAULT_PERS_STRING; |
79 | |
80 | #define RAND_DRBG_TYPE_FLAGS ( \ |
81 | RAND_DRBG_FLAG_MASTER | RAND_DRBG_FLAG_PUBLIC | RAND_DRBG_FLAG_PRIVATE ) |
82 | |
83 | #define RAND_DRBG_TYPE_MASTER 0 |
84 | #define RAND_DRBG_TYPE_PUBLIC 1 |
85 | #define RAND_DRBG_TYPE_PRIVATE 2 |
86 | |
87 | /* Defaults */ |
88 | static int rand_drbg_type[3] = { |
89 | RAND_DRBG_TYPE, /* Master */ |
90 | RAND_DRBG_TYPE, /* Public */ |
91 | RAND_DRBG_TYPE /* Private */ |
92 | }; |
93 | static unsigned int rand_drbg_flags[3] = { |
94 | RAND_DRBG_FLAGS | RAND_DRBG_FLAG_MASTER, /* Master */ |
95 | RAND_DRBG_FLAGS | RAND_DRBG_FLAG_PUBLIC, /* Public */ |
96 | RAND_DRBG_FLAGS | RAND_DRBG_FLAG_PRIVATE /* Private */ |
97 | }; |
98 | |
99 | static unsigned int master_reseed_interval = MASTER_RESEED_INTERVAL; |
100 | static unsigned int slave_reseed_interval = SLAVE_RESEED_INTERVAL; |
101 | |
102 | static time_t master_reseed_time_interval = MASTER_RESEED_TIME_INTERVAL; |
103 | static time_t slave_reseed_time_interval = SLAVE_RESEED_TIME_INTERVAL; |
104 | |
105 | /* A logical OR of all used DRBG flag bits (currently there is only one) */ |
106 | static const unsigned int rand_drbg_used_flags = |
107 | RAND_DRBG_FLAG_CTR_NO_DF | RAND_DRBG_FLAG_HMAC | RAND_DRBG_TYPE_FLAGS; |
108 | |
109 | |
110 | static RAND_DRBG *drbg_setup(OPENSSL_CTX *ctx, RAND_DRBG *parent, int drbg_type); |
111 | |
112 | static RAND_DRBG *rand_drbg_new(OPENSSL_CTX *ctx, |
113 | int secure, |
114 | int type, |
115 | unsigned int flags, |
116 | RAND_DRBG *parent); |
117 | |
118 | static int is_ctr(int type) |
119 | { |
120 | switch (type) { |
121 | case NID_aes_128_ctr: |
122 | case NID_aes_192_ctr: |
123 | case NID_aes_256_ctr: |
124 | return 1; |
125 | default: |
126 | return 0; |
127 | } |
128 | } |
129 | |
130 | static int is_digest(int type) |
131 | { |
132 | switch (type) { |
133 | case NID_sha1: |
134 | case NID_sha224: |
135 | case NID_sha256: |
136 | case NID_sha384: |
137 | case NID_sha512: |
138 | case NID_sha512_224: |
139 | case NID_sha512_256: |
140 | case NID_sha3_224: |
141 | case NID_sha3_256: |
142 | case NID_sha3_384: |
143 | case NID_sha3_512: |
144 | return 1; |
145 | default: |
146 | return 0; |
147 | } |
148 | } |
149 | |
150 | /* |
151 | * Initialize the OPENSSL_CTX global DRBGs on first use. |
152 | * Returns the allocated global data on success or NULL on failure. |
153 | */ |
154 | static void *drbg_ossl_ctx_new(OPENSSL_CTX *libctx) |
155 | { |
156 | DRBG_GLOBAL *dgbl = OPENSSL_zalloc(sizeof(*dgbl)); |
157 | |
158 | if (dgbl == NULL) |
159 | return NULL; |
160 | |
161 | #ifndef FIPS_MODE |
162 | /* |
163 | * We need to ensure that base libcrypto thread handling has been |
164 | * initialised. |
165 | */ |
166 | OPENSSL_init_crypto(0, NULL); |
167 | #endif |
168 | |
169 | if (!CRYPTO_THREAD_init_local(&dgbl->private_drbg, NULL)) |
170 | goto err1; |
171 | |
172 | if (!CRYPTO_THREAD_init_local(&dgbl->public_drbg, NULL)) |
173 | goto err2; |
174 | |
175 | dgbl->master_drbg = drbg_setup(libctx, NULL, RAND_DRBG_TYPE_MASTER); |
176 | if (dgbl->master_drbg == NULL) |
177 | goto err3; |
178 | |
179 | return dgbl; |
180 | |
181 | err3: |
182 | CRYPTO_THREAD_cleanup_local(&dgbl->public_drbg); |
183 | err2: |
184 | CRYPTO_THREAD_cleanup_local(&dgbl->private_drbg); |
185 | err1: |
186 | OPENSSL_free(dgbl); |
187 | return NULL; |
188 | } |
189 | |
190 | static void drbg_ossl_ctx_free(void *vdgbl) |
191 | { |
192 | DRBG_GLOBAL *dgbl = vdgbl; |
193 | |
194 | if (dgbl == NULL) |
195 | return; |
196 | |
197 | RAND_DRBG_free(dgbl->master_drbg); |
198 | CRYPTO_THREAD_cleanup_local(&dgbl->private_drbg); |
199 | CRYPTO_THREAD_cleanup_local(&dgbl->public_drbg); |
200 | |
201 | OPENSSL_free(dgbl); |
202 | } |
203 | |
204 | static const OPENSSL_CTX_METHOD drbg_ossl_ctx_method = { |
205 | drbg_ossl_ctx_new, |
206 | drbg_ossl_ctx_free, |
207 | }; |
208 | |
209 | /* |
210 | * drbg_ossl_ctx_new() calls drgb_setup() which calls rand_drbg_get_nonce() |
211 | * which needs to get the rand_nonce_lock out of the OPENSSL_CTX...but since |
212 | * drbg_ossl_ctx_new() hasn't finished running yet we need the rand_nonce_lock |
213 | * to be in a different global data object. Otherwise we will go into an |
214 | * infinite recursion loop. |
215 | */ |
216 | static void *drbg_nonce_ossl_ctx_new(OPENSSL_CTX *libctx) |
217 | { |
218 | DRBG_NONCE_GLOBAL *dngbl = OPENSSL_zalloc(sizeof(*dngbl)); |
219 | |
220 | if (dngbl == NULL) |
221 | return NULL; |
222 | |
223 | dngbl->rand_nonce_lock = CRYPTO_THREAD_lock_new(); |
224 | if (dngbl->rand_nonce_lock == NULL) { |
225 | OPENSSL_free(dngbl); |
226 | return NULL; |
227 | } |
228 | |
229 | return dngbl; |
230 | } |
231 | |
232 | static void drbg_nonce_ossl_ctx_free(void *vdngbl) |
233 | { |
234 | DRBG_NONCE_GLOBAL *dngbl = vdngbl; |
235 | |
236 | if (dngbl == NULL) |
237 | return; |
238 | |
239 | CRYPTO_THREAD_lock_free(dngbl->rand_nonce_lock); |
240 | |
241 | OPENSSL_free(dngbl); |
242 | } |
243 | |
244 | static const OPENSSL_CTX_METHOD drbg_nonce_ossl_ctx_method = { |
245 | drbg_nonce_ossl_ctx_new, |
246 | drbg_nonce_ossl_ctx_free, |
247 | }; |
248 | |
249 | static DRBG_GLOBAL *drbg_get_global(OPENSSL_CTX *libctx) |
250 | { |
251 | return openssl_ctx_get_data(libctx, OPENSSL_CTX_DRBG_INDEX, |
252 | &drbg_ossl_ctx_method); |
253 | } |
254 | |
255 | /* Implements the get_nonce() callback (see RAND_DRBG_set_callbacks()) */ |
256 | size_t rand_drbg_get_nonce(RAND_DRBG *drbg, |
257 | unsigned char **pout, |
258 | int entropy, size_t min_len, size_t max_len) |
259 | { |
260 | size_t ret = 0; |
261 | RAND_POOL *pool; |
262 | DRBG_NONCE_GLOBAL *dngbl |
263 | = openssl_ctx_get_data(drbg->libctx, OPENSSL_CTX_DRBG_NONCE_INDEX, |
264 | &drbg_nonce_ossl_ctx_method); |
265 | struct { |
266 | void *instance; |
267 | int count; |
268 | } data; |
269 | |
270 | if (dngbl == NULL) |
271 | return 0; |
272 | |
273 | memset(&data, 0, sizeof(data)); |
274 | pool = rand_pool_new(0, 0, min_len, max_len); |
275 | if (pool == NULL) |
276 | return 0; |
277 | |
278 | if (rand_pool_add_nonce_data(pool) == 0) |
279 | goto err; |
280 | |
281 | data.instance = drbg; |
282 | CRYPTO_atomic_add(&dngbl->rand_nonce_count, 1, &data.count, |
283 | dngbl->rand_nonce_lock); |
284 | |
285 | if (rand_pool_add(pool, (unsigned char *)&data, sizeof(data), 0) == 0) |
286 | goto err; |
287 | |
288 | ret = rand_pool_length(pool); |
289 | *pout = rand_pool_detach(pool); |
290 | |
291 | err: |
292 | rand_pool_free(pool); |
293 | |
294 | return ret; |
295 | } |
296 | |
297 | /* |
298 | * Implements the cleanup_nonce() callback (see RAND_DRBG_set_callbacks()) |
299 | * |
300 | */ |
301 | void rand_drbg_cleanup_nonce(RAND_DRBG *drbg, |
302 | unsigned char *out, size_t outlen) |
303 | { |
304 | OPENSSL_clear_free(out, outlen); |
305 | } |
306 | |
307 | /* |
308 | * Set/initialize |drbg| to be of type |type|, with optional |flags|. |
309 | * |
310 | * If |type| and |flags| are zero, use the defaults |
311 | * |
312 | * Returns 1 on success, 0 on failure. |
313 | */ |
314 | int RAND_DRBG_set(RAND_DRBG *drbg, int type, unsigned int flags) |
315 | { |
316 | int ret = 1; |
317 | |
318 | if (type == 0 && flags == 0) { |
319 | type = rand_drbg_type[RAND_DRBG_TYPE_MASTER]; |
320 | flags = rand_drbg_flags[RAND_DRBG_TYPE_MASTER]; |
321 | } |
322 | |
323 | /* If set is called multiple times - clear the old one */ |
324 | if (drbg->type != 0 && (type != drbg->type || flags != drbg->flags)) { |
325 | drbg->meth->uninstantiate(drbg); |
326 | rand_pool_free(drbg->adin_pool); |
327 | drbg->adin_pool = NULL; |
328 | } |
329 | |
330 | drbg->state = DRBG_UNINITIALISED; |
331 | drbg->flags = flags; |
332 | drbg->type = type; |
333 | |
334 | if (type == 0) { |
335 | /* Uninitialized; that's okay. */ |
336 | drbg->meth = NULL; |
337 | return 1; |
338 | } else if (is_ctr(type)) { |
339 | ret = drbg_ctr_init(drbg); |
340 | } else if (is_digest(type)) { |
341 | if (flags & RAND_DRBG_FLAG_HMAC) |
342 | ret = drbg_hmac_init(drbg); |
343 | else |
344 | ret = drbg_hash_init(drbg); |
345 | } else { |
346 | drbg->type = 0; |
347 | drbg->flags = 0; |
348 | drbg->meth = NULL; |
349 | RANDerr(RAND_F_RAND_DRBG_SET, RAND_R_UNSUPPORTED_DRBG_TYPE); |
350 | return 0; |
351 | } |
352 | |
353 | if (ret == 0) { |
354 | drbg->state = DRBG_ERROR; |
355 | RANDerr(RAND_F_RAND_DRBG_SET, RAND_R_ERROR_INITIALISING_DRBG); |
356 | } |
357 | return ret; |
358 | } |
359 | |
360 | /* |
361 | * Set/initialize default |type| and |flag| for new drbg instances. |
362 | * |
363 | * Returns 1 on success, 0 on failure. |
364 | */ |
365 | int RAND_DRBG_set_defaults(int type, unsigned int flags) |
366 | { |
367 | int all; |
368 | if (!(is_digest(type) || is_ctr(type))) { |
369 | RANDerr(RAND_F_RAND_DRBG_SET_DEFAULTS, RAND_R_UNSUPPORTED_DRBG_TYPE); |
370 | return 0; |
371 | } |
372 | |
373 | if ((flags & ~rand_drbg_used_flags) != 0) { |
374 | RANDerr(RAND_F_RAND_DRBG_SET_DEFAULTS, RAND_R_UNSUPPORTED_DRBG_FLAGS); |
375 | return 0; |
376 | } |
377 | |
378 | all = ((flags & RAND_DRBG_TYPE_FLAGS) == 0); |
379 | if (all || (flags & RAND_DRBG_FLAG_MASTER) != 0) { |
380 | rand_drbg_type[RAND_DRBG_TYPE_MASTER] = type; |
381 | rand_drbg_flags[RAND_DRBG_TYPE_MASTER] = flags | RAND_DRBG_FLAG_MASTER; |
382 | } |
383 | if (all || (flags & RAND_DRBG_FLAG_PUBLIC) != 0) { |
384 | rand_drbg_type[RAND_DRBG_TYPE_PUBLIC] = type; |
385 | rand_drbg_flags[RAND_DRBG_TYPE_PUBLIC] = flags | RAND_DRBG_FLAG_PUBLIC; |
386 | } |
387 | if (all || (flags & RAND_DRBG_FLAG_PRIVATE) != 0) { |
388 | rand_drbg_type[RAND_DRBG_TYPE_PRIVATE] = type; |
389 | rand_drbg_flags[RAND_DRBG_TYPE_PRIVATE] = flags | RAND_DRBG_FLAG_PRIVATE; |
390 | } |
391 | return 1; |
392 | } |
393 | |
394 | |
395 | /* |
396 | * Allocate memory and initialize a new DRBG. The DRBG is allocated on |
397 | * the secure heap if |secure| is nonzero and the secure heap is enabled. |
398 | * The |parent|, if not NULL, will be used as random source for reseeding. |
399 | * |
400 | * Returns a pointer to the new DRBG instance on success, NULL on failure. |
401 | */ |
402 | static RAND_DRBG *rand_drbg_new(OPENSSL_CTX *ctx, |
403 | int secure, |
404 | int type, |
405 | unsigned int flags, |
406 | RAND_DRBG *parent) |
407 | { |
408 | RAND_DRBG *drbg = secure ? OPENSSL_secure_zalloc(sizeof(*drbg)) |
409 | : OPENSSL_zalloc(sizeof(*drbg)); |
410 | |
411 | if (drbg == NULL) { |
412 | RANDerr(RAND_F_RAND_DRBG_NEW, ERR_R_MALLOC_FAILURE); |
413 | return NULL; |
414 | } |
415 | |
416 | drbg->libctx = ctx; |
417 | drbg->secure = secure && CRYPTO_secure_allocated(drbg); |
418 | drbg->fork_id = openssl_get_fork_id(); |
419 | drbg->parent = parent; |
420 | |
421 | if (parent == NULL) { |
422 | #ifdef FIPS_MODE |
423 | drbg->get_entropy = rand_crngt_get_entropy; |
424 | drbg->cleanup_entropy = rand_crngt_cleanup_entropy; |
425 | #else |
426 | drbg->get_entropy = rand_drbg_get_entropy; |
427 | drbg->cleanup_entropy = rand_drbg_cleanup_entropy; |
428 | #endif |
429 | #ifndef RAND_DRBG_GET_RANDOM_NONCE |
430 | drbg->get_nonce = rand_drbg_get_nonce; |
431 | drbg->cleanup_nonce = rand_drbg_cleanup_nonce; |
432 | #endif |
433 | |
434 | drbg->reseed_interval = master_reseed_interval; |
435 | drbg->reseed_time_interval = master_reseed_time_interval; |
436 | } else { |
437 | drbg->get_entropy = rand_drbg_get_entropy; |
438 | drbg->cleanup_entropy = rand_drbg_cleanup_entropy; |
439 | /* |
440 | * Do not provide nonce callbacks, the child DRBGs will |
441 | * obtain their nonce using random bits from the parent. |
442 | */ |
443 | |
444 | drbg->reseed_interval = slave_reseed_interval; |
445 | drbg->reseed_time_interval = slave_reseed_time_interval; |
446 | } |
447 | |
448 | if (RAND_DRBG_set(drbg, type, flags) == 0) |
449 | goto err; |
450 | |
451 | if (parent != NULL) { |
452 | rand_drbg_lock(parent); |
453 | if (drbg->strength > parent->strength) { |
454 | /* |
455 | * We currently don't support the algorithm from NIST SP 800-90C |
456 | * 10.1.2 to use a weaker DRBG as source |
457 | */ |
458 | rand_drbg_unlock(parent); |
459 | RANDerr(RAND_F_RAND_DRBG_NEW, RAND_R_PARENT_STRENGTH_TOO_WEAK); |
460 | goto err; |
461 | } |
462 | rand_drbg_unlock(parent); |
463 | } |
464 | |
465 | return drbg; |
466 | |
467 | err: |
468 | RAND_DRBG_free(drbg); |
469 | |
470 | return NULL; |
471 | } |
472 | |
473 | RAND_DRBG *RAND_DRBG_new_ex(OPENSSL_CTX *ctx, int type, unsigned int flags, |
474 | RAND_DRBG *parent) |
475 | { |
476 | return rand_drbg_new(ctx, 0, type, flags, parent); |
477 | } |
478 | |
479 | RAND_DRBG *RAND_DRBG_new(int type, unsigned int flags, RAND_DRBG *parent) |
480 | { |
481 | return RAND_DRBG_new_ex(NULL, type, flags, parent); |
482 | } |
483 | |
484 | RAND_DRBG *RAND_DRBG_secure_new_ex(OPENSSL_CTX *ctx, int type, |
485 | unsigned int flags, RAND_DRBG *parent) |
486 | { |
487 | return rand_drbg_new(ctx, 1, type, flags, parent); |
488 | } |
489 | |
490 | RAND_DRBG *RAND_DRBG_secure_new(int type, unsigned int flags, RAND_DRBG *parent) |
491 | { |
492 | return RAND_DRBG_secure_new_ex(NULL, type, flags, parent); |
493 | } |
494 | /* |
495 | * Uninstantiate |drbg| and free all memory. |
496 | */ |
497 | void RAND_DRBG_free(RAND_DRBG *drbg) |
498 | { |
499 | if (drbg == NULL) |
500 | return; |
501 | |
502 | if (drbg->meth != NULL) |
503 | drbg->meth->uninstantiate(drbg); |
504 | rand_pool_free(drbg->adin_pool); |
505 | CRYPTO_THREAD_lock_free(drbg->lock); |
506 | CRYPTO_free_ex_data(CRYPTO_EX_INDEX_RAND_DRBG, drbg, &drbg->ex_data); |
507 | |
508 | if (drbg->secure) |
509 | OPENSSL_secure_clear_free(drbg, sizeof(*drbg)); |
510 | else |
511 | OPENSSL_clear_free(drbg, sizeof(*drbg)); |
512 | } |
513 | |
514 | /* |
515 | * Instantiate |drbg|, after it has been initialized. Use |pers| and |
516 | * |perslen| as prediction-resistance input. |
517 | * |
518 | * Requires that drbg->lock is already locked for write, if non-null. |
519 | * |
520 | * Returns 1 on success, 0 on failure. |
521 | */ |
522 | int RAND_DRBG_instantiate(RAND_DRBG *drbg, |
523 | const unsigned char *pers, size_t perslen) |
524 | { |
525 | unsigned char *nonce = NULL, *entropy = NULL; |
526 | size_t noncelen = 0, entropylen = 0; |
527 | size_t min_entropy = drbg->strength; |
528 | size_t min_entropylen = drbg->min_entropylen; |
529 | size_t max_entropylen = drbg->max_entropylen; |
530 | |
531 | if (perslen > drbg->max_perslen) { |
532 | RANDerr(RAND_F_RAND_DRBG_INSTANTIATE, |
533 | RAND_R_PERSONALISATION_STRING_TOO_LONG); |
534 | goto end; |
535 | } |
536 | |
537 | if (drbg->meth == NULL) { |
538 | RANDerr(RAND_F_RAND_DRBG_INSTANTIATE, |
539 | RAND_R_NO_DRBG_IMPLEMENTATION_SELECTED); |
540 | goto end; |
541 | } |
542 | |
543 | if (drbg->state != DRBG_UNINITIALISED) { |
544 | if (drbg->state == DRBG_ERROR) |
545 | RANDerr(RAND_F_RAND_DRBG_INSTANTIATE, RAND_R_IN_ERROR_STATE); |
546 | else |
547 | RANDerr(RAND_F_RAND_DRBG_INSTANTIATE, RAND_R_ALREADY_INSTANTIATED); |
548 | goto end; |
549 | } |
550 | |
551 | drbg->state = DRBG_ERROR; |
552 | |
553 | /* |
554 | * NIST SP800-90Ar1 section 9.1 says you can combine getting the entropy |
555 | * and nonce in 1 call by increasing the entropy with 50% and increasing |
556 | * the minimum length to accommodate the length of the nonce. |
557 | * We do this in case a nonce is require and get_nonce is NULL. |
558 | */ |
559 | if (drbg->min_noncelen > 0 && drbg->get_nonce == NULL) { |
560 | min_entropy += drbg->strength / 2; |
561 | min_entropylen += drbg->min_noncelen; |
562 | max_entropylen += drbg->max_noncelen; |
563 | } |
564 | |
565 | drbg->reseed_next_counter = tsan_load(&drbg->reseed_prop_counter); |
566 | if (drbg->reseed_next_counter) { |
567 | drbg->reseed_next_counter++; |
568 | if(!drbg->reseed_next_counter) |
569 | drbg->reseed_next_counter = 1; |
570 | } |
571 | |
572 | if (drbg->get_entropy != NULL) |
573 | entropylen = drbg->get_entropy(drbg, &entropy, min_entropy, |
574 | min_entropylen, max_entropylen, 0); |
575 | if (entropylen < min_entropylen |
576 | || entropylen > max_entropylen) { |
577 | RANDerr(RAND_F_RAND_DRBG_INSTANTIATE, RAND_R_ERROR_RETRIEVING_ENTROPY); |
578 | goto end; |
579 | } |
580 | |
581 | if (drbg->min_noncelen > 0 && drbg->get_nonce != NULL) { |
582 | noncelen = drbg->get_nonce(drbg, &nonce, drbg->strength / 2, |
583 | drbg->min_noncelen, drbg->max_noncelen); |
584 | if (noncelen < drbg->min_noncelen || noncelen > drbg->max_noncelen) { |
585 | RANDerr(RAND_F_RAND_DRBG_INSTANTIATE, RAND_R_ERROR_RETRIEVING_NONCE); |
586 | goto end; |
587 | } |
588 | } |
589 | |
590 | if (!drbg->meth->instantiate(drbg, entropy, entropylen, |
591 | nonce, noncelen, pers, perslen)) { |
592 | RANDerr(RAND_F_RAND_DRBG_INSTANTIATE, RAND_R_ERROR_INSTANTIATING_DRBG); |
593 | goto end; |
594 | } |
595 | |
596 | drbg->state = DRBG_READY; |
597 | drbg->reseed_gen_counter = 1; |
598 | drbg->reseed_time = time(NULL); |
599 | tsan_store(&drbg->reseed_prop_counter, drbg->reseed_next_counter); |
600 | |
601 | end: |
602 | if (entropy != NULL && drbg->cleanup_entropy != NULL) |
603 | drbg->cleanup_entropy(drbg, entropy, entropylen); |
604 | if (nonce != NULL && drbg->cleanup_nonce != NULL) |
605 | drbg->cleanup_nonce(drbg, nonce, noncelen); |
606 | if (drbg->state == DRBG_READY) |
607 | return 1; |
608 | return 0; |
609 | } |
610 | |
611 | /* |
612 | * Uninstantiate |drbg|. Must be instantiated before it can be used. |
613 | * |
614 | * Requires that drbg->lock is already locked for write, if non-null. |
615 | * |
616 | * Returns 1 on success, 0 on failure. |
617 | */ |
618 | int RAND_DRBG_uninstantiate(RAND_DRBG *drbg) |
619 | { |
620 | int index = -1, type, flags; |
621 | if (drbg->meth == NULL) { |
622 | drbg->state = DRBG_ERROR; |
623 | RANDerr(RAND_F_RAND_DRBG_UNINSTANTIATE, |
624 | RAND_R_NO_DRBG_IMPLEMENTATION_SELECTED); |
625 | return 0; |
626 | } |
627 | |
628 | /* Clear the entire drbg->ctr struct, then reset some important |
629 | * members of the drbg->ctr struct (e.g. keysize, df_ks) to their |
630 | * initial values. |
631 | */ |
632 | drbg->meth->uninstantiate(drbg); |
633 | |
634 | /* The reset uses the default values for type and flags */ |
635 | if (drbg->flags & RAND_DRBG_FLAG_MASTER) |
636 | index = RAND_DRBG_TYPE_MASTER; |
637 | else if (drbg->flags & RAND_DRBG_FLAG_PRIVATE) |
638 | index = RAND_DRBG_TYPE_PRIVATE; |
639 | else if (drbg->flags & RAND_DRBG_FLAG_PUBLIC) |
640 | index = RAND_DRBG_TYPE_PUBLIC; |
641 | |
642 | if (index != -1) { |
643 | flags = rand_drbg_flags[index]; |
644 | type = rand_drbg_type[index]; |
645 | } else { |
646 | flags = drbg->flags; |
647 | type = drbg->type; |
648 | } |
649 | return RAND_DRBG_set(drbg, type, flags); |
650 | } |
651 | |
652 | /* |
653 | * Reseed |drbg|, mixing in the specified data |
654 | * |
655 | * Requires that drbg->lock is already locked for write, if non-null. |
656 | * |
657 | * Returns 1 on success, 0 on failure. |
658 | */ |
659 | int RAND_DRBG_reseed(RAND_DRBG *drbg, |
660 | const unsigned char *adin, size_t adinlen, |
661 | int prediction_resistance) |
662 | { |
663 | unsigned char *entropy = NULL; |
664 | size_t entropylen = 0; |
665 | |
666 | if (drbg->state == DRBG_ERROR) { |
667 | RANDerr(RAND_F_RAND_DRBG_RESEED, RAND_R_IN_ERROR_STATE); |
668 | return 0; |
669 | } |
670 | if (drbg->state == DRBG_UNINITIALISED) { |
671 | RANDerr(RAND_F_RAND_DRBG_RESEED, RAND_R_NOT_INSTANTIATED); |
672 | return 0; |
673 | } |
674 | |
675 | if (adin == NULL) { |
676 | adinlen = 0; |
677 | } else if (adinlen > drbg->max_adinlen) { |
678 | RANDerr(RAND_F_RAND_DRBG_RESEED, RAND_R_ADDITIONAL_INPUT_TOO_LONG); |
679 | return 0; |
680 | } |
681 | |
682 | drbg->state = DRBG_ERROR; |
683 | |
684 | drbg->reseed_next_counter = tsan_load(&drbg->reseed_prop_counter); |
685 | if (drbg->reseed_next_counter) { |
686 | drbg->reseed_next_counter++; |
687 | if(!drbg->reseed_next_counter) |
688 | drbg->reseed_next_counter = 1; |
689 | } |
690 | |
691 | if (drbg->get_entropy != NULL) |
692 | entropylen = drbg->get_entropy(drbg, &entropy, drbg->strength, |
693 | drbg->min_entropylen, |
694 | drbg->max_entropylen, |
695 | prediction_resistance); |
696 | if (entropylen < drbg->min_entropylen |
697 | || entropylen > drbg->max_entropylen) { |
698 | RANDerr(RAND_F_RAND_DRBG_RESEED, RAND_R_ERROR_RETRIEVING_ENTROPY); |
699 | goto end; |
700 | } |
701 | |
702 | if (!drbg->meth->reseed(drbg, entropy, entropylen, adin, adinlen)) |
703 | goto end; |
704 | |
705 | drbg->state = DRBG_READY; |
706 | drbg->reseed_gen_counter = 1; |
707 | drbg->reseed_time = time(NULL); |
708 | tsan_store(&drbg->reseed_prop_counter, drbg->reseed_next_counter); |
709 | |
710 | end: |
711 | if (entropy != NULL && drbg->cleanup_entropy != NULL) |
712 | drbg->cleanup_entropy(drbg, entropy, entropylen); |
713 | if (drbg->state == DRBG_READY) |
714 | return 1; |
715 | return 0; |
716 | } |
717 | |
718 | /* |
719 | * Restart |drbg|, using the specified entropy or additional input |
720 | * |
721 | * Tries its best to get the drbg instantiated by all means, |
722 | * regardless of its current state. |
723 | * |
724 | * Optionally, a |buffer| of |len| random bytes can be passed, |
725 | * which is assumed to contain at least |entropy| bits of entropy. |
726 | * |
727 | * If |entropy| > 0, the buffer content is used as entropy input. |
728 | * |
729 | * If |entropy| == 0, the buffer content is used as additional input |
730 | * |
731 | * Returns 1 on success, 0 on failure. |
732 | * |
733 | * This function is used internally only. |
734 | */ |
735 | int rand_drbg_restart(RAND_DRBG *drbg, |
736 | const unsigned char *buffer, size_t len, size_t entropy) |
737 | { |
738 | int reseeded = 0; |
739 | const unsigned char *adin = NULL; |
740 | size_t adinlen = 0; |
741 | |
742 | if (drbg->seed_pool != NULL) { |
743 | RANDerr(RAND_F_RAND_DRBG_RESTART, ERR_R_INTERNAL_ERROR); |
744 | drbg->state = DRBG_ERROR; |
745 | rand_pool_free(drbg->seed_pool); |
746 | drbg->seed_pool = NULL; |
747 | return 0; |
748 | } |
749 | |
750 | if (buffer != NULL) { |
751 | if (entropy > 0) { |
752 | if (drbg->max_entropylen < len) { |
753 | RANDerr(RAND_F_RAND_DRBG_RESTART, |
754 | RAND_R_ENTROPY_INPUT_TOO_LONG); |
755 | drbg->state = DRBG_ERROR; |
756 | return 0; |
757 | } |
758 | |
759 | if (entropy > 8 * len) { |
760 | RANDerr(RAND_F_RAND_DRBG_RESTART, RAND_R_ENTROPY_OUT_OF_RANGE); |
761 | drbg->state = DRBG_ERROR; |
762 | return 0; |
763 | } |
764 | |
765 | /* will be picked up by the rand_drbg_get_entropy() callback */ |
766 | drbg->seed_pool = rand_pool_attach(buffer, len, entropy); |
767 | if (drbg->seed_pool == NULL) |
768 | return 0; |
769 | } else { |
770 | if (drbg->max_adinlen < len) { |
771 | RANDerr(RAND_F_RAND_DRBG_RESTART, |
772 | RAND_R_ADDITIONAL_INPUT_TOO_LONG); |
773 | drbg->state = DRBG_ERROR; |
774 | return 0; |
775 | } |
776 | adin = buffer; |
777 | adinlen = len; |
778 | } |
779 | } |
780 | |
781 | /* repair error state */ |
782 | if (drbg->state == DRBG_ERROR) |
783 | RAND_DRBG_uninstantiate(drbg); |
784 | |
785 | /* repair uninitialized state */ |
786 | if (drbg->state == DRBG_UNINITIALISED) { |
787 | /* reinstantiate drbg */ |
788 | RAND_DRBG_instantiate(drbg, |
789 | (const unsigned char *) ossl_pers_string, |
790 | sizeof(ossl_pers_string) - 1); |
791 | /* already reseeded. prevent second reseeding below */ |
792 | reseeded = (drbg->state == DRBG_READY); |
793 | } |
794 | |
795 | /* refresh current state if entropy or additional input has been provided */ |
796 | if (drbg->state == DRBG_READY) { |
797 | if (adin != NULL) { |
798 | /* |
799 | * mix in additional input without reseeding |
800 | * |
801 | * Similar to RAND_DRBG_reseed(), but the provided additional |
802 | * data |adin| is mixed into the current state without pulling |
803 | * entropy from the trusted entropy source using get_entropy(). |
804 | * This is not a reseeding in the strict sense of NIST SP 800-90A. |
805 | */ |
806 | drbg->meth->reseed(drbg, adin, adinlen, NULL, 0); |
807 | } else if (reseeded == 0) { |
808 | /* do a full reseeding if it has not been done yet above */ |
809 | RAND_DRBG_reseed(drbg, NULL, 0, 0); |
810 | } |
811 | } |
812 | |
813 | rand_pool_free(drbg->seed_pool); |
814 | drbg->seed_pool = NULL; |
815 | |
816 | return drbg->state == DRBG_READY; |
817 | } |
818 | |
819 | /* |
820 | * Generate |outlen| bytes into the buffer at |out|. Reseed if we need |
821 | * to or if |prediction_resistance| is set. Additional input can be |
822 | * sent in |adin| and |adinlen|. |
823 | * |
824 | * Requires that drbg->lock is already locked for write, if non-null. |
825 | * |
826 | * Returns 1 on success, 0 on failure. |
827 | * |
828 | */ |
829 | int RAND_DRBG_generate(RAND_DRBG *drbg, unsigned char *out, size_t outlen, |
830 | int prediction_resistance, |
831 | const unsigned char *adin, size_t adinlen) |
832 | { |
833 | int fork_id; |
834 | int reseed_required = 0; |
835 | |
836 | if (drbg->state != DRBG_READY) { |
837 | /* try to recover from previous errors */ |
838 | rand_drbg_restart(drbg, NULL, 0, 0); |
839 | |
840 | if (drbg->state == DRBG_ERROR) { |
841 | RANDerr(RAND_F_RAND_DRBG_GENERATE, RAND_R_IN_ERROR_STATE); |
842 | return 0; |
843 | } |
844 | if (drbg->state == DRBG_UNINITIALISED) { |
845 | RANDerr(RAND_F_RAND_DRBG_GENERATE, RAND_R_NOT_INSTANTIATED); |
846 | return 0; |
847 | } |
848 | } |
849 | |
850 | if (outlen > drbg->max_request) { |
851 | RANDerr(RAND_F_RAND_DRBG_GENERATE, RAND_R_REQUEST_TOO_LARGE_FOR_DRBG); |
852 | return 0; |
853 | } |
854 | if (adinlen > drbg->max_adinlen) { |
855 | RANDerr(RAND_F_RAND_DRBG_GENERATE, RAND_R_ADDITIONAL_INPUT_TOO_LONG); |
856 | return 0; |
857 | } |
858 | |
859 | fork_id = openssl_get_fork_id(); |
860 | |
861 | if (drbg->fork_id != fork_id) { |
862 | drbg->fork_id = fork_id; |
863 | reseed_required = 1; |
864 | } |
865 | |
866 | if (drbg->reseed_interval > 0) { |
867 | if (drbg->reseed_gen_counter > drbg->reseed_interval) |
868 | reseed_required = 1; |
869 | } |
870 | if (drbg->reseed_time_interval > 0) { |
871 | time_t now = time(NULL); |
872 | if (now < drbg->reseed_time |
873 | || now - drbg->reseed_time >= drbg->reseed_time_interval) |
874 | reseed_required = 1; |
875 | } |
876 | if (drbg->parent != NULL) { |
877 | unsigned int reseed_counter = tsan_load(&drbg->reseed_prop_counter); |
878 | if (reseed_counter > 0 |
879 | && tsan_load(&drbg->parent->reseed_prop_counter) |
880 | != reseed_counter) |
881 | reseed_required = 1; |
882 | } |
883 | |
884 | if (reseed_required || prediction_resistance) { |
885 | if (!RAND_DRBG_reseed(drbg, adin, adinlen, prediction_resistance)) { |
886 | RANDerr(RAND_F_RAND_DRBG_GENERATE, RAND_R_RESEED_ERROR); |
887 | return 0; |
888 | } |
889 | adin = NULL; |
890 | adinlen = 0; |
891 | } |
892 | |
893 | if (!drbg->meth->generate(drbg, out, outlen, adin, adinlen)) { |
894 | drbg->state = DRBG_ERROR; |
895 | RANDerr(RAND_F_RAND_DRBG_GENERATE, RAND_R_GENERATE_ERROR); |
896 | return 0; |
897 | } |
898 | |
899 | drbg->reseed_gen_counter++; |
900 | |
901 | return 1; |
902 | } |
903 | |
904 | /* |
905 | * Generates |outlen| random bytes and stores them in |out|. It will |
906 | * using the given |drbg| to generate the bytes. |
907 | * |
908 | * Requires that drbg->lock is already locked for write, if non-null. |
909 | * |
910 | * Returns 1 on success 0 on failure. |
911 | */ |
912 | int RAND_DRBG_bytes(RAND_DRBG *drbg, unsigned char *out, size_t outlen) |
913 | { |
914 | unsigned char *additional = NULL; |
915 | size_t additional_len; |
916 | size_t chunk; |
917 | size_t ret = 0; |
918 | |
919 | if (drbg->adin_pool == NULL) { |
920 | if (drbg->type == 0) |
921 | goto err; |
922 | drbg->adin_pool = rand_pool_new(0, 0, 0, drbg->max_adinlen); |
923 | if (drbg->adin_pool == NULL) |
924 | goto err; |
925 | } |
926 | |
927 | additional_len = rand_drbg_get_additional_data(drbg->adin_pool, |
928 | &additional); |
929 | |
930 | for ( ; outlen > 0; outlen -= chunk, out += chunk) { |
931 | chunk = outlen; |
932 | if (chunk > drbg->max_request) |
933 | chunk = drbg->max_request; |
934 | ret = RAND_DRBG_generate(drbg, out, chunk, 0, additional, additional_len); |
935 | if (!ret) |
936 | goto err; |
937 | } |
938 | ret = 1; |
939 | |
940 | err: |
941 | if (additional != NULL) |
942 | rand_drbg_cleanup_additional_data(drbg->adin_pool, additional); |
943 | |
944 | return ret; |
945 | } |
946 | |
947 | /* |
948 | * Set the RAND_DRBG callbacks for obtaining entropy and nonce. |
949 | * |
950 | * Setting the callbacks is allowed only if the drbg has not been |
951 | * initialized yet. Otherwise, the operation will fail. |
952 | * |
953 | * Returns 1 on success, 0 on failure. |
954 | */ |
955 | int RAND_DRBG_set_callbacks(RAND_DRBG *drbg, |
956 | RAND_DRBG_get_entropy_fn get_entropy, |
957 | RAND_DRBG_cleanup_entropy_fn cleanup_entropy, |
958 | RAND_DRBG_get_nonce_fn get_nonce, |
959 | RAND_DRBG_cleanup_nonce_fn cleanup_nonce) |
960 | { |
961 | if (drbg->state != DRBG_UNINITIALISED |
962 | || drbg->parent != NULL) |
963 | return 0; |
964 | drbg->get_entropy = get_entropy; |
965 | drbg->cleanup_entropy = cleanup_entropy; |
966 | drbg->get_nonce = get_nonce; |
967 | drbg->cleanup_nonce = cleanup_nonce; |
968 | return 1; |
969 | } |
970 | |
971 | /* |
972 | * Set the reseed interval. |
973 | * |
974 | * The drbg will reseed automatically whenever the number of generate |
975 | * requests exceeds the given reseed interval. If the reseed interval |
976 | * is 0, then this feature is disabled. |
977 | * |
978 | * Returns 1 on success, 0 on failure. |
979 | */ |
980 | int RAND_DRBG_set_reseed_interval(RAND_DRBG *drbg, unsigned int interval) |
981 | { |
982 | if (interval > MAX_RESEED_INTERVAL) |
983 | return 0; |
984 | drbg->reseed_interval = interval; |
985 | return 1; |
986 | } |
987 | |
988 | /* |
989 | * Set the reseed time interval. |
990 | * |
991 | * The drbg will reseed automatically whenever the time elapsed since |
992 | * the last reseeding exceeds the given reseed time interval. For safety, |
993 | * a reseeding will also occur if the clock has been reset to a smaller |
994 | * value. |
995 | * |
996 | * Returns 1 on success, 0 on failure. |
997 | */ |
998 | int RAND_DRBG_set_reseed_time_interval(RAND_DRBG *drbg, time_t interval) |
999 | { |
1000 | if (interval > MAX_RESEED_TIME_INTERVAL) |
1001 | return 0; |
1002 | drbg->reseed_time_interval = interval; |
1003 | return 1; |
1004 | } |
1005 | |
1006 | /* |
1007 | * Set the default values for reseed (time) intervals of new DRBG instances |
1008 | * |
1009 | * The default values can be set independently for master DRBG instances |
1010 | * (without a parent) and slave DRBG instances (with parent). |
1011 | * |
1012 | * Returns 1 on success, 0 on failure. |
1013 | */ |
1014 | |
1015 | int RAND_DRBG_set_reseed_defaults( |
1016 | unsigned int _master_reseed_interval, |
1017 | unsigned int _slave_reseed_interval, |
1018 | time_t _master_reseed_time_interval, |
1019 | time_t _slave_reseed_time_interval |
1020 | ) |
1021 | { |
1022 | if (_master_reseed_interval > MAX_RESEED_INTERVAL |
1023 | || _slave_reseed_interval > MAX_RESEED_INTERVAL) |
1024 | return 0; |
1025 | |
1026 | if (_master_reseed_time_interval > MAX_RESEED_TIME_INTERVAL |
1027 | || _slave_reseed_time_interval > MAX_RESEED_TIME_INTERVAL) |
1028 | return 0; |
1029 | |
1030 | master_reseed_interval = _master_reseed_interval; |
1031 | slave_reseed_interval = _slave_reseed_interval; |
1032 | |
1033 | master_reseed_time_interval = _master_reseed_time_interval; |
1034 | slave_reseed_time_interval = _slave_reseed_time_interval; |
1035 | |
1036 | return 1; |
1037 | } |
1038 | |
1039 | /* |
1040 | * Locks the given drbg. Locking a drbg which does not have locking |
1041 | * enabled is considered a successful no-op. |
1042 | * |
1043 | * Returns 1 on success, 0 on failure. |
1044 | */ |
1045 | int rand_drbg_lock(RAND_DRBG *drbg) |
1046 | { |
1047 | if (drbg->lock != NULL) |
1048 | return CRYPTO_THREAD_write_lock(drbg->lock); |
1049 | |
1050 | return 1; |
1051 | } |
1052 | |
1053 | /* |
1054 | * Unlocks the given drbg. Unlocking a drbg which does not have locking |
1055 | * enabled is considered a successful no-op. |
1056 | * |
1057 | * Returns 1 on success, 0 on failure. |
1058 | */ |
1059 | int rand_drbg_unlock(RAND_DRBG *drbg) |
1060 | { |
1061 | if (drbg->lock != NULL) |
1062 | return CRYPTO_THREAD_unlock(drbg->lock); |
1063 | |
1064 | return 1; |
1065 | } |
1066 | |
1067 | /* |
1068 | * Enables locking for the given drbg |
1069 | * |
1070 | * Locking can only be enabled if the random generator |
1071 | * is in the uninitialized state. |
1072 | * |
1073 | * Returns 1 on success, 0 on failure. |
1074 | */ |
1075 | int rand_drbg_enable_locking(RAND_DRBG *drbg) |
1076 | { |
1077 | if (drbg->state != DRBG_UNINITIALISED) { |
1078 | RANDerr(RAND_F_RAND_DRBG_ENABLE_LOCKING, |
1079 | RAND_R_DRBG_ALREADY_INITIALIZED); |
1080 | return 0; |
1081 | } |
1082 | |
1083 | if (drbg->lock == NULL) { |
1084 | if (drbg->parent != NULL && drbg->parent->lock == NULL) { |
1085 | RANDerr(RAND_F_RAND_DRBG_ENABLE_LOCKING, |
1086 | RAND_R_PARENT_LOCKING_NOT_ENABLED); |
1087 | return 0; |
1088 | } |
1089 | |
1090 | drbg->lock = CRYPTO_THREAD_lock_new(); |
1091 | if (drbg->lock == NULL) { |
1092 | RANDerr(RAND_F_RAND_DRBG_ENABLE_LOCKING, |
1093 | RAND_R_FAILED_TO_CREATE_LOCK); |
1094 | return 0; |
1095 | } |
1096 | } |
1097 | |
1098 | return 1; |
1099 | } |
1100 | |
1101 | /* |
1102 | * Get and set the EXDATA |
1103 | */ |
1104 | int RAND_DRBG_set_ex_data(RAND_DRBG *drbg, int idx, void *arg) |
1105 | { |
1106 | return CRYPTO_set_ex_data(&drbg->ex_data, idx, arg); |
1107 | } |
1108 | |
1109 | void *RAND_DRBG_get_ex_data(const RAND_DRBG *drbg, int idx) |
1110 | { |
1111 | return CRYPTO_get_ex_data(&drbg->ex_data, idx); |
1112 | } |
1113 | |
1114 | |
1115 | /* |
1116 | * The following functions provide a RAND_METHOD that works on the |
1117 | * global DRBG. They lock. |
1118 | */ |
1119 | |
1120 | /* |
1121 | * Allocates a new global DRBG on the secure heap (if enabled) and |
1122 | * initializes it with default settings. |
1123 | * |
1124 | * Returns a pointer to the new DRBG instance on success, NULL on failure. |
1125 | */ |
1126 | static RAND_DRBG *drbg_setup(OPENSSL_CTX *ctx, RAND_DRBG *parent, int drbg_type) |
1127 | { |
1128 | RAND_DRBG *drbg; |
1129 | |
1130 | drbg = RAND_DRBG_secure_new_ex(ctx, rand_drbg_type[drbg_type], |
1131 | rand_drbg_flags[drbg_type], parent); |
1132 | if (drbg == NULL) |
1133 | return NULL; |
1134 | |
1135 | /* Only the master DRBG needs to have a lock */ |
1136 | if (parent == NULL && rand_drbg_enable_locking(drbg) == 0) |
1137 | goto err; |
1138 | |
1139 | /* enable seed propagation */ |
1140 | tsan_store(&drbg->reseed_prop_counter, 1); |
1141 | |
1142 | /* |
1143 | * Ignore instantiation error to support just-in-time instantiation. |
1144 | * |
1145 | * The state of the drbg will be checked in RAND_DRBG_generate() and |
1146 | * an automatic recovery is attempted. |
1147 | */ |
1148 | (void)RAND_DRBG_instantiate(drbg, |
1149 | (const unsigned char *) ossl_pers_string, |
1150 | sizeof(ossl_pers_string) - 1); |
1151 | return drbg; |
1152 | |
1153 | err: |
1154 | RAND_DRBG_free(drbg); |
1155 | return NULL; |
1156 | } |
1157 | |
1158 | static void drbg_delete_thread_state(void *arg) |
1159 | { |
1160 | OPENSSL_CTX *ctx = arg; |
1161 | DRBG_GLOBAL *dgbl = drbg_get_global(ctx); |
1162 | RAND_DRBG *drbg; |
1163 | |
1164 | if (dgbl == NULL) |
1165 | return; |
1166 | drbg = CRYPTO_THREAD_get_local(&dgbl->public_drbg); |
1167 | CRYPTO_THREAD_set_local(&dgbl->public_drbg, NULL); |
1168 | RAND_DRBG_free(drbg); |
1169 | |
1170 | drbg = CRYPTO_THREAD_get_local(&dgbl->private_drbg); |
1171 | CRYPTO_THREAD_set_local(&dgbl->private_drbg, NULL); |
1172 | RAND_DRBG_free(drbg); |
1173 | } |
1174 | |
1175 | /* Implements the default OpenSSL RAND_bytes() method */ |
1176 | static int drbg_bytes(unsigned char *out, int count) |
1177 | { |
1178 | int ret; |
1179 | RAND_DRBG *drbg = RAND_DRBG_get0_public(); |
1180 | |
1181 | if (drbg == NULL) |
1182 | return 0; |
1183 | |
1184 | ret = RAND_DRBG_bytes(drbg, out, count); |
1185 | |
1186 | return ret; |
1187 | } |
1188 | |
1189 | /* |
1190 | * Calculates the minimum length of a full entropy buffer |
1191 | * which is necessary to seed (i.e. instantiate) the DRBG |
1192 | * successfully. |
1193 | */ |
1194 | size_t rand_drbg_seedlen(RAND_DRBG *drbg) |
1195 | { |
1196 | /* |
1197 | * If no os entropy source is available then RAND_seed(buffer, bufsize) |
1198 | * is expected to succeed if and only if the buffer length satisfies |
1199 | * the following requirements, which follow from the calculations |
1200 | * in RAND_DRBG_instantiate(). |
1201 | */ |
1202 | size_t min_entropy = drbg->strength; |
1203 | size_t min_entropylen = drbg->min_entropylen; |
1204 | |
1205 | /* |
1206 | * Extra entropy for the random nonce in the absence of a |
1207 | * get_nonce callback, see comment in RAND_DRBG_instantiate(). |
1208 | */ |
1209 | if (drbg->min_noncelen > 0 && drbg->get_nonce == NULL) { |
1210 | min_entropy += drbg->strength / 2; |
1211 | min_entropylen += drbg->min_noncelen; |
1212 | } |
1213 | |
1214 | /* |
1215 | * Convert entropy requirement from bits to bytes |
1216 | * (dividing by 8 without rounding upwards, because |
1217 | * all entropy requirements are divisible by 8). |
1218 | */ |
1219 | min_entropy >>= 3; |
1220 | |
1221 | /* Return a value that satisfies both requirements */ |
1222 | return min_entropy > min_entropylen ? min_entropy : min_entropylen; |
1223 | } |
1224 | |
1225 | /* Implements the default OpenSSL RAND_add() method */ |
1226 | static int drbg_add(const void *buf, int num, double randomness) |
1227 | { |
1228 | int ret = 0; |
1229 | RAND_DRBG *drbg = RAND_DRBG_get0_master(); |
1230 | size_t buflen; |
1231 | size_t seedlen; |
1232 | |
1233 | if (drbg == NULL) |
1234 | return 0; |
1235 | |
1236 | if (num < 0 || randomness < 0.0) |
1237 | return 0; |
1238 | |
1239 | rand_drbg_lock(drbg); |
1240 | seedlen = rand_drbg_seedlen(drbg); |
1241 | |
1242 | buflen = (size_t)num; |
1243 | |
1244 | #ifdef FIPS_MODE |
1245 | /* |
1246 | * NIST SP-800-90A mandates that entropy *shall not* be provided |
1247 | * by the consuming application. By setting the randomness to zero, |
1248 | * we ensure that the buffer contents will be added to the internal |
1249 | * state of the DRBG only as additional data. |
1250 | * |
1251 | * (NIST SP-800-90Ar1, Sections 9.1 and 9.2) |
1252 | */ |
1253 | randomness = 0.0; |
1254 | #endif |
1255 | if (buflen < seedlen || randomness < (double) seedlen) { |
1256 | #if defined(OPENSSL_RAND_SEED_NONE) |
1257 | /* |
1258 | * If no os entropy source is available, a reseeding will fail |
1259 | * inevitably. So we use a trick to mix the buffer contents into |
1260 | * the DRBG state without forcing a reseeding: we generate a |
1261 | * dummy random byte, using the buffer content as additional data. |
1262 | * Note: This won't work with RAND_DRBG_FLAG_CTR_NO_DF. |
1263 | */ |
1264 | unsigned char dummy[1]; |
1265 | |
1266 | ret = RAND_DRBG_generate(drbg, dummy, sizeof(dummy), 0, buf, buflen); |
1267 | rand_drbg_unlock(drbg); |
1268 | return ret; |
1269 | #else |
1270 | /* |
1271 | * If an os entropy source is available then we declare the buffer content |
1272 | * as additional data by setting randomness to zero and trigger a regular |
1273 | * reseeding. |
1274 | */ |
1275 | randomness = 0.0; |
1276 | #endif |
1277 | } |
1278 | |
1279 | if (randomness > (double)seedlen) { |
1280 | /* |
1281 | * The purpose of this check is to bound |randomness| by a |
1282 | * relatively small value in order to prevent an integer |
1283 | * overflow when multiplying by 8 in the rand_drbg_restart() |
1284 | * call below. Note that randomness is measured in bytes, |
1285 | * not bits, so this value corresponds to eight times the |
1286 | * security strength. |
1287 | */ |
1288 | randomness = (double)seedlen; |
1289 | } |
1290 | |
1291 | ret = rand_drbg_restart(drbg, buf, buflen, (size_t)(8 * randomness)); |
1292 | rand_drbg_unlock(drbg); |
1293 | |
1294 | return ret; |
1295 | } |
1296 | |
1297 | /* Implements the default OpenSSL RAND_seed() method */ |
1298 | static int drbg_seed(const void *buf, int num) |
1299 | { |
1300 | return drbg_add(buf, num, num); |
1301 | } |
1302 | |
1303 | /* Implements the default OpenSSL RAND_status() method */ |
1304 | static int drbg_status(void) |
1305 | { |
1306 | int ret; |
1307 | RAND_DRBG *drbg = RAND_DRBG_get0_master(); |
1308 | |
1309 | if (drbg == NULL) |
1310 | return 0; |
1311 | |
1312 | rand_drbg_lock(drbg); |
1313 | ret = drbg->state == DRBG_READY ? 1 : 0; |
1314 | rand_drbg_unlock(drbg); |
1315 | return ret; |
1316 | } |
1317 | |
1318 | /* |
1319 | * Get the master DRBG. |
1320 | * Returns pointer to the DRBG on success, NULL on failure. |
1321 | * |
1322 | */ |
1323 | RAND_DRBG *OPENSSL_CTX_get0_master_drbg(OPENSSL_CTX *ctx) |
1324 | { |
1325 | DRBG_GLOBAL *dgbl = drbg_get_global(ctx); |
1326 | |
1327 | if (dgbl == NULL) |
1328 | return NULL; |
1329 | |
1330 | return dgbl->master_drbg; |
1331 | } |
1332 | |
1333 | RAND_DRBG *RAND_DRBG_get0_master(void) |
1334 | { |
1335 | return OPENSSL_CTX_get0_master_drbg(NULL); |
1336 | } |
1337 | |
1338 | /* |
1339 | * Get the public DRBG. |
1340 | * Returns pointer to the DRBG on success, NULL on failure. |
1341 | */ |
1342 | RAND_DRBG *OPENSSL_CTX_get0_public_drbg(OPENSSL_CTX *ctx) |
1343 | { |
1344 | DRBG_GLOBAL *dgbl = drbg_get_global(ctx); |
1345 | RAND_DRBG *drbg; |
1346 | |
1347 | if (dgbl == NULL) |
1348 | return NULL; |
1349 | |
1350 | drbg = CRYPTO_THREAD_get_local(&dgbl->public_drbg); |
1351 | if (drbg == NULL) { |
1352 | ctx = openssl_ctx_get_concrete(ctx); |
1353 | if (!ossl_init_thread_start(NULL, ctx, drbg_delete_thread_state)) |
1354 | return NULL; |
1355 | drbg = drbg_setup(ctx, dgbl->master_drbg, RAND_DRBG_TYPE_PUBLIC); |
1356 | CRYPTO_THREAD_set_local(&dgbl->public_drbg, drbg); |
1357 | } |
1358 | return drbg; |
1359 | } |
1360 | |
1361 | RAND_DRBG *RAND_DRBG_get0_public(void) |
1362 | { |
1363 | return OPENSSL_CTX_get0_public_drbg(NULL); |
1364 | } |
1365 | |
1366 | /* |
1367 | * Get the private DRBG. |
1368 | * Returns pointer to the DRBG on success, NULL on failure. |
1369 | */ |
1370 | RAND_DRBG *OPENSSL_CTX_get0_private_drbg(OPENSSL_CTX *ctx) |
1371 | { |
1372 | DRBG_GLOBAL *dgbl = drbg_get_global(ctx); |
1373 | RAND_DRBG *drbg; |
1374 | |
1375 | if (dgbl == NULL) |
1376 | return NULL; |
1377 | |
1378 | drbg = CRYPTO_THREAD_get_local(&dgbl->private_drbg); |
1379 | if (drbg == NULL) { |
1380 | ctx = openssl_ctx_get_concrete(ctx); |
1381 | if (!ossl_init_thread_start(NULL, ctx, drbg_delete_thread_state)) |
1382 | return NULL; |
1383 | drbg = drbg_setup(ctx, dgbl->master_drbg, RAND_DRBG_TYPE_PRIVATE); |
1384 | CRYPTO_THREAD_set_local(&dgbl->private_drbg, drbg); |
1385 | } |
1386 | return drbg; |
1387 | } |
1388 | |
1389 | RAND_DRBG *RAND_DRBG_get0_private(void) |
1390 | { |
1391 | return OPENSSL_CTX_get0_private_drbg(NULL); |
1392 | } |
1393 | |
1394 | RAND_METHOD rand_meth = { |
1395 | drbg_seed, |
1396 | drbg_bytes, |
1397 | NULL, |
1398 | drbg_add, |
1399 | drbg_bytes, |
1400 | drbg_status |
1401 | }; |
1402 | |
1403 | RAND_METHOD *RAND_OpenSSL(void) |
1404 | { |
1405 | #ifndef FIPS_MODE |
1406 | return &rand_meth; |
1407 | #else |
1408 | return NULL; |
1409 | #endif |
1410 | } |
1411 | |