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>
15 #include "internal/thread_once.h"
16 #include "internal/rand_int.h"
18 static RAND_DRBG rand_drbg; /* The default global DRBG. */
19 static RAND_DRBG priv_drbg; /* The global private-key DRBG. */
22 * Support framework for NIST SP 800-90A DRBG, AES-CTR mode.
23 * The RAND_DRBG is OpenSSL's pointer to an instance of the DRBG.
25 * The OpenSSL model is to have new and free functions, and that new
26 * does all initialization. That is not the NIST model, which has
27 * instantiation and un-instantiate, and re-use within a new/free
28 * lifecycle. (No doubt this comes from the desire to support hardware
29 * DRBG, where allocation of resources on something like an HSM is
30 * a much bigger deal than just re-setting an allocated resource.)
33 static CRYPTO_ONCE rand_init_drbg = CRYPTO_ONCE_STATIC_INIT;
36 * Set/initialize |drbg| to be of type |nid|, with optional |flags|.
37 * Return -2 if the type is not supported, 1 on success and -1 on
40 int RAND_DRBG_set(RAND_DRBG *drbg, int nid, unsigned int flags)
44 drbg->state = DRBG_UNINITIALISED;
50 RANDerr(RAND_F_RAND_DRBG_SET, RAND_R_UNSUPPORTED_DRBG_TYPE);
53 /* Uninitialized; that's okay. */
63 RANDerr(RAND_F_RAND_DRBG_SET, RAND_R_ERROR_INITIALISING_DRBG);
68 * Allocate memory and initialize a new DRBG. The |parent|, if not
69 * NULL, will be used to auto-seed this RAND_DRBG as needed.
71 RAND_DRBG *RAND_DRBG_new(int type, unsigned int flags, RAND_DRBG *parent)
73 RAND_DRBG *drbg = OPENSSL_zalloc(sizeof(*drbg));
76 RANDerr(RAND_F_RAND_DRBG_NEW, ERR_R_MALLOC_FAILURE);
79 drbg->size = RANDOMNESS_NEEDED;
80 drbg->fork_count = rand_fork_count;
81 drbg->parent = parent;
82 if (RAND_DRBG_set(drbg, type, flags) < 0)
86 if (!RAND_DRBG_set_callbacks(drbg, drbg_entropy_from_parent,
100 * Uninstantiate |drbg| and free all memory.
102 void RAND_DRBG_free(RAND_DRBG *drbg)
104 /* The global DRBG is free'd by rand_cleanup_drbg_int() */
105 if (drbg == NULL || drbg == &rand_drbg)
108 ctr_uninstantiate(drbg);
109 CRYPTO_free_ex_data(CRYPTO_EX_INDEX_DRBG, drbg, &drbg->ex_data);
110 OPENSSL_clear_free(drbg, sizeof(*drbg));
114 * Instantiate |drbg|, after it has been initialized. Use |pers| and
115 * |perslen| as prediction-resistance input.
117 int RAND_DRBG_instantiate(RAND_DRBG *drbg,
118 const unsigned char *pers, size_t perslen)
120 unsigned char *nonce = NULL, *entropy = NULL;
121 size_t noncelen = 0, entropylen = 0;
123 if (perslen > drbg->max_perslen) {
124 RANDerr(RAND_F_RAND_DRBG_INSTANTIATE,
125 RAND_R_PERSONALISATION_STRING_TOO_LONG);
128 if (drbg->state != DRBG_UNINITIALISED) {
129 RANDerr(RAND_F_RAND_DRBG_INSTANTIATE,
130 drbg->state == DRBG_ERROR ? RAND_R_IN_ERROR_STATE
131 : RAND_R_ALREADY_INSTANTIATED);
135 drbg->state = DRBG_ERROR;
136 if (drbg->get_entropy != NULL)
137 entropylen = drbg->get_entropy(drbg, &entropy, drbg->strength,
138 drbg->min_entropylen, drbg->max_entropylen);
139 if (entropylen < drbg->min_entropylen || entropylen > drbg->max_entropylen) {
140 RANDerr(RAND_F_RAND_DRBG_INSTANTIATE, RAND_R_ERROR_RETRIEVING_ENTROPY);
144 if (drbg->max_noncelen > 0 && drbg->get_nonce != NULL) {
145 noncelen = drbg->get_nonce(drbg, &nonce, drbg->strength / 2,
146 drbg->min_noncelen, drbg->max_noncelen);
147 if (noncelen < drbg->min_noncelen || noncelen > drbg->max_noncelen) {
148 RANDerr(RAND_F_RAND_DRBG_INSTANTIATE, RAND_R_ERROR_RETRIEVING_NONCE);
153 if (!ctr_instantiate(drbg, entropy, entropylen,
154 nonce, noncelen, pers, perslen)) {
155 RANDerr(RAND_F_RAND_DRBG_INSTANTIATE, RAND_R_ERROR_INSTANTIATING_DRBG);
159 drbg->state = DRBG_READY;
160 drbg->reseed_counter = 1;
163 if (entropy != NULL && drbg->cleanup_entropy != NULL)
164 drbg->cleanup_entropy(drbg, entropy, entropylen);
165 if (nonce != NULL && drbg->cleanup_nonce!= NULL )
166 drbg->cleanup_nonce(drbg, nonce, noncelen);
167 if (drbg->state == DRBG_READY)
173 * Uninstantiate |drbg|. Must be instantiated before it can be used.
175 int RAND_DRBG_uninstantiate(RAND_DRBG *drbg)
177 int ret = ctr_uninstantiate(drbg);
179 OPENSSL_cleanse(&drbg->ctr, sizeof(drbg->ctr));
180 drbg->state = DRBG_UNINITIALISED;
185 * Mix in the specified data to reseed |drbg|.
187 int RAND_DRBG_reseed(RAND_DRBG *drbg,
188 const unsigned char *adin, size_t adinlen)
190 unsigned char *entropy = NULL;
191 size_t entropylen = 0;
193 if (drbg->state == DRBG_ERROR) {
194 RANDerr(RAND_F_RAND_DRBG_RESEED, RAND_R_IN_ERROR_STATE);
197 if (drbg->state == DRBG_UNINITIALISED) {
198 RANDerr(RAND_F_RAND_DRBG_RESEED, RAND_R_NOT_INSTANTIATED);
204 else if (adinlen > drbg->max_adinlen) {
205 RANDerr(RAND_F_RAND_DRBG_RESEED, RAND_R_ADDITIONAL_INPUT_TOO_LONG);
209 drbg->state = DRBG_ERROR;
210 if (drbg->get_entropy != NULL)
211 entropylen = drbg->get_entropy(drbg, &entropy, drbg->strength,
212 drbg->min_entropylen, drbg->max_entropylen);
213 if (entropylen < drbg->min_entropylen || entropylen > drbg->max_entropylen) {
214 RANDerr(RAND_F_RAND_DRBG_RESEED, RAND_R_ERROR_RETRIEVING_ENTROPY);
218 if (!ctr_reseed(drbg, entropy, entropylen, adin, adinlen))
220 drbg->state = DRBG_READY;
221 drbg->reseed_counter = 1;
224 if (entropy != NULL && drbg->cleanup_entropy != NULL)
225 drbg->cleanup_entropy(drbg, entropy, entropylen);
226 if (drbg->state == DRBG_READY)
232 * Generate |outlen| bytes into the buffer at |out|. Reseed if we need
233 * to or if |prediction_resistance| is set. Additional input can be
234 * sent in |adin| and |adinlen|.
236 int RAND_DRBG_generate(RAND_DRBG *drbg, unsigned char *out, size_t outlen,
237 int prediction_resistance,
238 const unsigned char *adin, size_t adinlen)
240 if (drbg->state == DRBG_ERROR) {
241 RANDerr(RAND_F_RAND_DRBG_GENERATE, RAND_R_IN_ERROR_STATE);
244 if (drbg->state == DRBG_UNINITIALISED) {
245 RANDerr(RAND_F_RAND_DRBG_GENERATE, RAND_R_NOT_INSTANTIATED);
248 if (outlen > drbg->max_request) {
249 RANDerr(RAND_F_RAND_DRBG_GENERATE, RAND_R_REQUEST_TOO_LARGE_FOR_DRBG);
252 if (adinlen > drbg->max_adinlen) {
253 RANDerr(RAND_F_RAND_DRBG_GENERATE, RAND_R_ADDITIONAL_INPUT_TOO_LONG);
257 if (drbg->fork_count != rand_fork_count) {
258 drbg->fork_count = rand_fork_count;
259 drbg->state = DRBG_RESEED;
262 if (drbg->reseed_counter >= drbg->reseed_interval)
263 drbg->state = DRBG_RESEED;
265 if (drbg->state == DRBG_RESEED || prediction_resistance) {
266 if (!RAND_DRBG_reseed(drbg, adin, adinlen)) {
267 RANDerr(RAND_F_RAND_DRBG_GENERATE, RAND_R_RESEED_ERROR);
274 if (!ctr_generate(drbg, out, outlen, adin, adinlen)) {
275 drbg->state = DRBG_ERROR;
276 RANDerr(RAND_F_RAND_DRBG_GENERATE, RAND_R_GENERATE_ERROR);
280 if (drbg->reseed_counter >= drbg->reseed_interval)
281 drbg->state = DRBG_RESEED;
283 drbg->reseed_counter++;
288 * Set the callbacks for entropy and nonce. We currently don't use
289 * the nonce; that's mainly for the KATs
291 int RAND_DRBG_set_callbacks(RAND_DRBG *drbg,
292 RAND_DRBG_get_entropy_fn cb_get_entropy,
293 RAND_DRBG_cleanup_entropy_fn cb_cleanup_entropy,
294 RAND_DRBG_get_nonce_fn cb_get_nonce,
295 RAND_DRBG_cleanup_nonce_fn cb_cleanup_nonce)
297 if (drbg->state != DRBG_UNINITIALISED)
299 drbg->get_entropy = cb_get_entropy;
300 drbg->cleanup_entropy = cb_cleanup_entropy;
301 drbg->get_nonce = cb_get_nonce;
302 drbg->cleanup_nonce = cb_cleanup_nonce;
307 * Set the reseed interval.
309 int RAND_DRBG_set_reseed_interval(RAND_DRBG *drbg, int interval)
311 if (interval < 0 || interval > MAX_RESEED)
313 drbg->reseed_interval = interval;
318 * Get and set the EXDATA
320 int RAND_DRBG_set_ex_data(RAND_DRBG *drbg, int idx, void *arg)
322 return CRYPTO_set_ex_data(&drbg->ex_data, idx, arg);
325 void *RAND_DRBG_get_ex_data(const RAND_DRBG *drbg, int idx)
327 return CRYPTO_get_ex_data(&drbg->ex_data, idx);
332 * The following functions provide a RAND_METHOD that works on the
333 * global DRBG. They lock.
337 * Creates a global DRBG with default settings.
338 * Returns 1 on success, 0 on failure
340 static int setup_drbg(RAND_DRBG *drbg, const char *name)
344 drbg->lock = CRYPTO_THREAD_glock_new(name);
345 ret &= drbg->lock != NULL;
346 drbg->size = RANDOMNESS_NEEDED;
347 drbg->secure = CRYPTO_secure_malloc_initialized();
348 /* If you change these parameters, see RANDOMNESS_NEEDED */
349 ret &= RAND_DRBG_set(drbg,
350 NID_aes_128_ctr, RAND_DRBG_FLAG_CTR_USE_DF) == 1;
351 ret &= RAND_DRBG_set_callbacks(drbg, drbg_entropy_from_system,
352 drbg_release_entropy, NULL, NULL) == 1;
353 ret &= RAND_DRBG_instantiate(drbg, NULL, 0) == 1;
358 * Initialize the global DRBGs on first use.
359 * Returns 1 on success, 0 on failure.
361 DEFINE_RUN_ONCE_STATIC(do_rand_init_drbg)
365 ret &= setup_drbg(&rand_drbg, "rand_drbg");
366 ret &= setup_drbg(&priv_drbg, "priv_drbg");
371 /* Clean up a DRBG and free it */
372 static void free_drbg(RAND_DRBG *drbg)
374 CRYPTO_THREAD_lock_free(drbg->lock);
375 RAND_DRBG_uninstantiate(drbg);
378 /* Clean up the global DRBGs before exit */
379 void rand_cleanup_drbg_int(void)
381 free_drbg(&rand_drbg);
382 free_drbg(&priv_drbg);
385 static int drbg_bytes(unsigned char *out, int count)
389 RAND_DRBG *drbg = RAND_DRBG_get0_global();
394 CRYPTO_THREAD_write_lock(drbg->lock);
395 if (drbg->state == DRBG_UNINITIALISED)
398 for ( ; count > 0; count -= chunk, out += chunk) {
400 if (chunk > drbg->max_request)
401 chunk = drbg->max_request;
402 ret = RAND_DRBG_generate(drbg, out, chunk, 0, NULL, 0);
409 CRYPTO_THREAD_unlock(drbg->lock);
413 static int drbg_add(const void *buf, int num, double randomness)
415 unsigned char *in = (unsigned char *)buf;
416 unsigned char *out, *end;
418 CRYPTO_THREAD_write_lock(rand_bytes.lock);
419 out = &rand_bytes.buff[rand_bytes.curr];
420 end = &rand_bytes.buff[rand_bytes.size];
422 /* Copy whatever fits into the end of the buffer. */
423 for ( ; --num >= 0 && out < end; rand_bytes.curr++)
426 /* XOR any the leftover. */
428 for (out = rand_bytes.buff; --num >= 0 && out < end; )
432 CRYPTO_THREAD_unlock(rand_bytes.lock);
436 static int drbg_seed(const void *buf, int num)
438 return drbg_add(buf, num, num);
441 static int drbg_status(void)
444 RAND_DRBG *drbg = RAND_DRBG_get0_global();
449 CRYPTO_THREAD_write_lock(drbg->lock);
450 ret = drbg->state == DRBG_READY ? 1 : 0;
451 CRYPTO_THREAD_unlock(drbg->lock);
456 * Get the global public DRBG.
457 * Returns pointer to the DRBG on success, NULL on failure.
459 RAND_DRBG *RAND_DRBG_get0_global(void)
461 if (!RUN_ONCE(&rand_init_drbg, do_rand_init_drbg))
468 * Get the global private DRBG.
469 * Returns pointer to the DRBG on success, NULL on failure.
471 RAND_DRBG *RAND_DRBG_get0_priv_global(void)
473 if (!RUN_ONCE(&rand_init_drbg, do_rand_init_drbg))
479 RAND_METHOD rand_meth = {
488 RAND_METHOD *RAND_OpenSSL(void)