2 * Copyright 2011-2017 The OpenSSL Project Authors. All Rights Reserved.
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
11 #include <openssl/crypto.h>
12 #include <openssl/err.h>
13 #include <openssl/rand.h>
17 * Support framework for NIST SP 800-90A DRBG, AES-CTR mode.
18 * The RAND_DRBG is OpenSSL's pointer to an instance of the DRBG.
20 * The OpenSSL model is to have new and free functions, and that new
21 * does all initialization. That is not the NIST model, which has
22 * instantiation and un-instantiate, and re-use within a new/free
23 * lifecycle. (No doubt this comes from the desire to support hardware
24 * DRBG, where allocation of resources on something like an HSM is
25 * a much bigger deal than just re-setting an allocated resource.)
29 * Set/initialize |drbg| to be of type |nid|, with optional |flags|.
30 * Return -2 if the type is not supported, 1 on success and -1 on
33 int RAND_DRBG_set(RAND_DRBG *drbg, int nid, unsigned int flags)
37 drbg->state = DRBG_UNINITIALISED;
43 RANDerr(RAND_F_RAND_DRBG_SET, RAND_R_UNSUPPORTED_DRBG_TYPE);
46 /* Uninitialized; that's okay. */
56 RANDerr(RAND_F_RAND_DRBG_SET, RAND_R_ERROR_INITIALISING_DRBG);
61 * Allocate memory and initialize a new DRBG. The |parent|, if not
62 * NULL, will be used to auto-seed this RAND_DRBG as needed.
64 RAND_DRBG *RAND_DRBG_new(int type, unsigned int flags, RAND_DRBG *parent)
66 RAND_DRBG *drbg = OPENSSL_zalloc(sizeof(*drbg));
69 RANDerr(RAND_F_RAND_DRBG_NEW, ERR_R_MALLOC_FAILURE);
72 drbg->size = RANDOMNESS_NEEDED;
73 drbg->fork_count = rand_fork_count;
74 drbg->parent = parent;
75 if (RAND_DRBG_set(drbg, type, flags) < 0)
79 if (parent->state == DRBG_UNINITIALISED
80 && RAND_DRBG_instantiate(parent, NULL, 0) == 0)
82 if (!RAND_DRBG_set_callbacks(drbg, drbg_entropy_from_parent,
86 * Add in our address. Note we are adding the pointer
87 * itself, not its contents!
89 || !RAND_DRBG_instantiate(drbg,
90 (unsigned char*)&drbg, sizeof(drbg)))
101 RAND_DRBG *RAND_DRBG_get0_global(void)
107 * Uninstantiate |drbg| and free all memory.
109 void RAND_DRBG_free(RAND_DRBG *drbg)
111 /* The global DRBG is free'd by rand_cleanup_int() */
112 if (drbg == NULL || drbg == &rand_drbg)
115 ctr_uninstantiate(drbg);
116 CRYPTO_free_ex_data(CRYPTO_EX_INDEX_DRBG, drbg, &drbg->ex_data);
117 OPENSSL_clear_free(drbg, sizeof(*drbg));
121 * Instantiate |drbg|, after it has been initialized. Use |pers| and
122 * |perslen| as prediction-resistance input.
124 int RAND_DRBG_instantiate(RAND_DRBG *drbg,
125 const unsigned char *pers, size_t perslen)
127 unsigned char *nonce = NULL, *entropy = NULL;
128 size_t noncelen = 0, entropylen = 0;
130 if (perslen > drbg->max_perslen) {
131 RANDerr(RAND_F_RAND_DRBG_INSTANTIATE,
132 RAND_R_PERSONALISATION_STRING_TOO_LONG);
135 if (drbg->state != DRBG_UNINITIALISED) {
136 RANDerr(RAND_F_RAND_DRBG_INSTANTIATE,
137 drbg->state == DRBG_ERROR ? RAND_R_IN_ERROR_STATE
138 : RAND_R_ALREADY_INSTANTIATED);
142 drbg->state = DRBG_ERROR;
143 if (drbg->get_entropy != NULL)
144 entropylen = drbg->get_entropy(drbg, &entropy, drbg->strength,
145 drbg->min_entropylen, drbg->max_entropylen);
146 if (entropylen < drbg->min_entropylen || entropylen > drbg->max_entropylen) {
147 RANDerr(RAND_F_RAND_DRBG_INSTANTIATE, RAND_R_ERROR_RETRIEVING_ENTROPY);
151 if (drbg->max_noncelen > 0 && drbg->get_nonce != NULL) {
152 noncelen = drbg->get_nonce(drbg, &nonce, drbg->strength / 2,
153 drbg->min_noncelen, drbg->max_noncelen);
154 if (noncelen < drbg->min_noncelen || noncelen > drbg->max_noncelen) {
155 RANDerr(RAND_F_RAND_DRBG_INSTANTIATE, RAND_R_ERROR_RETRIEVING_NONCE);
160 if (!ctr_instantiate(drbg, entropy, entropylen,
161 nonce, noncelen, pers, perslen)) {
162 RANDerr(RAND_F_RAND_DRBG_INSTANTIATE, RAND_R_ERROR_INSTANTIATING_DRBG);
166 drbg->state = DRBG_READY;
167 drbg->reseed_counter = 1;
170 if (entropy != NULL && drbg->cleanup_entropy != NULL)
171 drbg->cleanup_entropy(drbg, entropy);
172 if (nonce != NULL && drbg->cleanup_nonce!= NULL )
173 drbg->cleanup_nonce(drbg, nonce);
174 if (drbg->state == DRBG_READY)
180 * Uninstantiate |drbg|. Must be instantiated before it can be used.
182 int RAND_DRBG_uninstantiate(RAND_DRBG *drbg)
184 int ret = ctr_uninstantiate(drbg);
186 OPENSSL_cleanse(&drbg->ctr, sizeof(drbg->ctr));
187 drbg->state = DRBG_UNINITIALISED;
192 * Mix in the specified data to reseed |drbg|.
194 int RAND_DRBG_reseed(RAND_DRBG *drbg,
195 const unsigned char *adin, size_t adinlen)
197 unsigned char *entropy = NULL;
198 size_t entropylen = 0;
200 if (drbg->state == DRBG_ERROR) {
201 RANDerr(RAND_F_RAND_DRBG_RESEED, RAND_R_IN_ERROR_STATE);
204 if (drbg->state == DRBG_UNINITIALISED) {
205 RANDerr(RAND_F_RAND_DRBG_RESEED, RAND_R_NOT_INSTANTIATED);
211 else if (adinlen > drbg->max_adinlen) {
212 RANDerr(RAND_F_RAND_DRBG_RESEED, RAND_R_ADDITIONAL_INPUT_TOO_LONG);
216 drbg->state = DRBG_ERROR;
217 if (drbg->get_entropy != NULL)
218 entropylen = drbg->get_entropy(drbg, &entropy, drbg->strength,
219 drbg->min_entropylen, drbg->max_entropylen);
220 if (entropylen < drbg->min_entropylen || entropylen > drbg->max_entropylen) {
221 RANDerr(RAND_F_RAND_DRBG_RESEED, RAND_R_ERROR_RETRIEVING_ENTROPY);
225 if (!ctr_reseed(drbg, entropy, entropylen, adin, adinlen))
227 drbg->state = DRBG_READY;
228 drbg->reseed_counter = 1;
231 if (entropy != NULL && drbg->cleanup_entropy != NULL)
232 drbg->cleanup_entropy(drbg, entropy);
233 if (drbg->state == DRBG_READY)
239 * Generate |outlen| bytes into the buffer at |out|. Reseed if we need
240 * to or if |prediction_resistance| is set. Additional input can be
241 * sent in |adin| and |adinlen|.
243 int RAND_DRBG_generate(RAND_DRBG *drbg, unsigned char *out, size_t outlen,
244 int prediction_resistance,
245 const unsigned char *adin, size_t adinlen)
247 if (drbg->state == DRBG_ERROR) {
248 RANDerr(RAND_F_RAND_DRBG_GENERATE, RAND_R_IN_ERROR_STATE);
251 if (drbg->state == DRBG_UNINITIALISED) {
252 RANDerr(RAND_F_RAND_DRBG_GENERATE, RAND_R_NOT_INSTANTIATED);
255 if (outlen > drbg->max_request) {
256 RANDerr(RAND_F_RAND_DRBG_GENERATE, RAND_R_REQUEST_TOO_LARGE_FOR_DRBG);
259 if (adinlen > drbg->max_adinlen) {
260 RANDerr(RAND_F_RAND_DRBG_GENERATE, RAND_R_ADDITIONAL_INPUT_TOO_LONG);
264 if (drbg->fork_count != rand_fork_count) {
265 drbg->fork_count = rand_fork_count;
266 drbg->state = DRBG_RESEED;
269 if (drbg->reseed_counter >= drbg->reseed_interval)
270 drbg->state = DRBG_RESEED;
272 if (drbg->state == DRBG_RESEED || prediction_resistance) {
273 if (!RAND_DRBG_reseed(drbg, adin, adinlen)) {
274 RANDerr(RAND_F_RAND_DRBG_GENERATE, RAND_R_RESEED_ERROR);
281 if (!ctr_generate(drbg, out, outlen, adin, adinlen)) {
282 drbg->state = DRBG_ERROR;
283 RANDerr(RAND_F_RAND_DRBG_GENERATE, RAND_R_GENERATE_ERROR);
287 if (drbg->reseed_counter >= drbg->reseed_interval)
288 drbg->state = DRBG_RESEED;
290 drbg->reseed_counter++;
295 * Set the callbacks for entropy and nonce. We currently don't use
296 * the nonce; that's mainly for the KATs
298 int RAND_DRBG_set_callbacks(RAND_DRBG *drbg,
299 RAND_DRBG_get_entropy_fn cb_get_entropy,
300 RAND_DRBG_cleanup_entropy_fn cb_cleanup_entropy,
301 RAND_DRBG_get_nonce_fn cb_get_nonce,
302 RAND_DRBG_cleanup_nonce_fn cb_cleanup_nonce)
304 if (drbg->state != DRBG_UNINITIALISED)
306 drbg->get_entropy = cb_get_entropy;
307 drbg->cleanup_entropy = cb_cleanup_entropy;
308 drbg->get_nonce = cb_get_nonce;
309 drbg->cleanup_nonce = cb_cleanup_nonce;
314 * Set the reseed interval.
316 int RAND_DRBG_set_reseed_interval(RAND_DRBG *drbg, int interval)
318 if (interval < 0 || interval > MAX_RESEED)
320 drbg->reseed_interval = interval;
325 * Get and set the EXDATA
327 int RAND_DRBG_set_ex_data(RAND_DRBG *drbg, int idx, void *arg)
329 return CRYPTO_set_ex_data(&drbg->ex_data, idx, arg);
332 void *RAND_DRBG_get_ex_data(const RAND_DRBG *drbg, int idx)
334 return CRYPTO_get_ex_data(&drbg->ex_data, idx);
339 * The following functions provide a RAND_METHOD that works on the
340 * global DRBG. They lock.
343 static int drbg_bytes(unsigned char *out, int count)
348 CRYPTO_THREAD_write_lock(rand_drbg.lock);
349 if (rand_drbg.state == DRBG_UNINITIALISED
350 && RAND_DRBG_instantiate(&rand_drbg, NULL, 0) == 0)
353 for ( ; count > 0; count -= chunk, out += chunk) {
355 if (chunk > rand_drbg.max_request)
356 chunk = rand_drbg.max_request;
357 ret = RAND_DRBG_generate(&rand_drbg, out, chunk, 0, NULL, 0);
364 CRYPTO_THREAD_unlock(rand_drbg.lock);
368 static int drbg_add(const void *buf, int num, double randomness)
370 unsigned char *in = (unsigned char *)buf;
371 unsigned char *out, *end;
373 CRYPTO_THREAD_write_lock(rand_bytes.lock);
374 out = &rand_bytes.buff[rand_bytes.curr];
375 end = &rand_bytes.buff[rand_bytes.size];
377 /* Copy whatever fits into the end of the buffer. */
378 for ( ; --num >= 0 && out < end; rand_bytes.curr++)
381 /* XOR any the leftover. */
383 for (out = rand_bytes.buff; --num >= 0 && out < end; )
387 CRYPTO_THREAD_unlock(rand_bytes.lock);
391 static int drbg_seed(const void *buf, int num)
393 return drbg_add(buf, num, num);
396 static int drbg_status(void)
400 CRYPTO_THREAD_write_lock(rand_drbg.lock);
401 if (rand_drbg.state == DRBG_UNINITIALISED)
402 RAND_DRBG_instantiate(&rand_drbg, NULL, 0);
403 ret = rand_drbg.state == DRBG_READY ? 1 : 0;
404 CRYPTO_THREAD_unlock(rand_drbg.lock);
408 RAND_DRBG rand_drbg; /* The default global DRBG. */
409 RAND_DRBG priv_drbg; /* The global private-key DRBG. */
411 RAND_METHOD rand_meth = {
420 RAND_METHOD *RAND_OpenSSL(void)