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Manuel Pégourié-Gonnard490bdf32014-01-27 14:03:10 +01001/**
2 * \file hmac_drbg.h
3 *
Gilles Peskinedb6f4142019-09-30 15:01:15 +02004 * \brief The HMAC_DRBG pseudorandom generator.
5 *
6 * This module implements the HMAC_DRBG pseudorandom generator described
7 * in <em>NIST SP 800-90A: Recommendation for Random Number Generation Using
8 * Deterministic Random Bit Generators</em>.
Darryl Greena40a1012018-01-05 15:33:17 +00009 */
10/*
Bence Szépkútia2947ac2020-08-19 16:37:36 +020011 * Copyright The Mbed TLS Contributors
Bence Szépkútif744bd72020-06-05 13:02:18 +020012 * SPDX-License-Identifier: Apache-2.0 OR GPL-2.0-or-later
13 *
14 * This file is provided under the Apache License 2.0, or the
15 * GNU General Public License v2.0 or later.
16 *
17 * **********
18 * Apache License 2.0:
Manuel Pégourié-Gonnard37ff1402015-09-04 14:21:07 +020019 *
20 * Licensed under the Apache License, Version 2.0 (the "License"); you may
21 * not use this file except in compliance with the License.
22 * You may obtain a copy of the License at
23 *
24 * http://www.apache.org/licenses/LICENSE-2.0
25 *
26 * Unless required by applicable law or agreed to in writing, software
27 * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
28 * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
29 * See the License for the specific language governing permissions and
30 * limitations under the License.
Manuel Pégourié-Gonnard490bdf32014-01-27 14:03:10 +010031 *
Bence Szépkútif744bd72020-06-05 13:02:18 +020032 * **********
33 *
34 * **********
35 * GNU General Public License v2.0 or later:
36 *
37 * This program is free software; you can redistribute it and/or modify
38 * it under the terms of the GNU General Public License as published by
39 * the Free Software Foundation; either version 2 of the License, or
40 * (at your option) any later version.
41 *
42 * This program is distributed in the hope that it will be useful,
43 * but WITHOUT ANY WARRANTY; without even the implied warranty of
44 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
45 * GNU General Public License for more details.
46 *
47 * You should have received a copy of the GNU General Public License along
48 * with this program; if not, write to the Free Software Foundation, Inc.,
49 * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
50 *
51 * **********
Manuel Pégourié-Gonnard490bdf32014-01-27 14:03:10 +010052 */
Manuel Pégourié-Gonnard2cf5a7c2015-04-08 12:49:31 +020053#ifndef MBEDTLS_HMAC_DRBG_H
54#define MBEDTLS_HMAC_DRBG_H
Manuel Pégourié-Gonnard490bdf32014-01-27 14:03:10 +010055
Ron Eldor8b0cf2e2018-02-14 16:02:41 +020056#if !defined(MBEDTLS_CONFIG_FILE)
57#include "config.h"
58#else
59#include MBEDTLS_CONFIG_FILE
60#endif
61
Manuel Pégourié-Gonnard490bdf32014-01-27 14:03:10 +010062#include "md.h"
63
Manuel Pégourié-Gonnard0a4fb092015-05-07 12:50:31 +010064#if defined(MBEDTLS_THREADING_C)
Ron Eldor6fd941f2017-05-14 16:17:33 +030065#include "threading.h"
Manuel Pégourié-Gonnard0a4fb092015-05-07 12:50:31 +010066#endif
67
Manuel Pégourié-Gonnardfe34a5f2014-01-30 15:06:40 +010068/*
Manuel Pégourié-Gonnard9a6e93e2014-03-11 09:34:02 +010069 * Error codes
Manuel Pégourié-Gonnardfe34a5f2014-01-30 15:06:40 +010070 */
Manuel Pégourié-Gonnard2cf5a7c2015-04-08 12:49:31 +020071#define MBEDTLS_ERR_HMAC_DRBG_REQUEST_TOO_BIG -0x0003 /**< Too many random requested in single call. */
72#define MBEDTLS_ERR_HMAC_DRBG_INPUT_TOO_BIG -0x0005 /**< Input too large (Entropy + additional). */
73#define MBEDTLS_ERR_HMAC_DRBG_FILE_IO_ERROR -0x0007 /**< Read/write error in file. */
74#define MBEDTLS_ERR_HMAC_DRBG_ENTROPY_SOURCE_FAILED -0x0009 /**< The entropy source failed. */
Manuel Pégourié-Gonnardfe34a5f2014-01-30 15:06:40 +010075
Paul Bakker088c5c52014-04-25 11:11:10 +020076/**
77 * \name SECTION: Module settings
78 *
79 * The configuration options you can set for this module are in this section.
80 * Either change them in config.h or define them on the compiler command line.
81 * \{
82 */
83
Manuel Pégourié-Gonnard2cf5a7c2015-04-08 12:49:31 +020084#if !defined(MBEDTLS_HMAC_DRBG_RESEED_INTERVAL)
85#define MBEDTLS_HMAC_DRBG_RESEED_INTERVAL 10000 /**< Interval before reseed is performed by default */
Paul Bakker088c5c52014-04-25 11:11:10 +020086#endif
87
Manuel Pégourié-Gonnard2cf5a7c2015-04-08 12:49:31 +020088#if !defined(MBEDTLS_HMAC_DRBG_MAX_INPUT)
89#define MBEDTLS_HMAC_DRBG_MAX_INPUT 256 /**< Maximum number of additional input bytes */
Paul Bakker088c5c52014-04-25 11:11:10 +020090#endif
91
Manuel Pégourié-Gonnard2cf5a7c2015-04-08 12:49:31 +020092#if !defined(MBEDTLS_HMAC_DRBG_MAX_REQUEST)
93#define MBEDTLS_HMAC_DRBG_MAX_REQUEST 1024 /**< Maximum number of requested bytes per call */
Paul Bakker088c5c52014-04-25 11:11:10 +020094#endif
95
Manuel Pégourié-Gonnard2cf5a7c2015-04-08 12:49:31 +020096#if !defined(MBEDTLS_HMAC_DRBG_MAX_SEED_INPUT)
97#define MBEDTLS_HMAC_DRBG_MAX_SEED_INPUT 384 /**< Maximum size of (re)seed buffer */
Paul Bakker088c5c52014-04-25 11:11:10 +020098#endif
99
100/* \} name SECTION: Module settings */
Manuel Pégourié-Gonnardfe34a5f2014-01-30 15:06:40 +0100101
Manuel Pégourié-Gonnard2cf5a7c2015-04-08 12:49:31 +0200102#define MBEDTLS_HMAC_DRBG_PR_OFF 0 /**< No prediction resistance */
103#define MBEDTLS_HMAC_DRBG_PR_ON 1 /**< Prediction resistance enabled */
Manuel Pégourié-Gonnardaf786ff2014-01-30 18:44:18 +0100104
Manuel Pégourié-Gonnard490bdf32014-01-27 14:03:10 +0100105#ifdef __cplusplus
106extern "C" {
107#endif
108
Manuel Pégourié-Gonnardfe34a5f2014-01-30 15:06:40 +0100109/**
110 * HMAC_DRBG context.
Manuel Pégourié-Gonnard490bdf32014-01-27 14:03:10 +0100111 */
Dawid Drozd428cc522018-07-24 10:02:47 +0200112typedef struct mbedtls_hmac_drbg_context
Manuel Pégourié-Gonnard490bdf32014-01-27 14:03:10 +0100113{
Antonin Décimod5f47592019-01-23 15:24:37 +0100114 /* Working state: the key K is not stored explicitly,
Manuel Pégourié-Gonnardb05db2a2014-02-01 11:38:05 +0100115 * but is implied by the HMAC context */
Manuel Pégourié-Gonnard2cf5a7c2015-04-08 12:49:31 +0200116 mbedtls_md_context_t md_ctx; /*!< HMAC context (inc. K) */
117 unsigned char V[MBEDTLS_MD_MAX_SIZE]; /*!< V in the spec */
Manuel Pégourié-Gonnardb05db2a2014-02-01 11:38:05 +0100118 int reseed_counter; /*!< reseed counter */
Manuel Pégourié-Gonnardfe34a5f2014-01-30 15:06:40 +0100119
Manuel Pégourié-Gonnard658dbed2014-01-30 19:03:45 +0100120 /* Administrative state */
Manuel Pégourié-Gonnardfe34a5f2014-01-30 15:06:40 +0100121 size_t entropy_len; /*!< entropy bytes grabbed on each (re)seed */
Manuel Pégourié-Gonnardaf786ff2014-01-30 18:44:18 +0100122 int prediction_resistance; /*!< enable prediction resistance (Automatic
123 reseed before every random generation) */
Manuel Pégourié-Gonnard658dbed2014-01-30 19:03:45 +0100124 int reseed_interval; /*!< reseed interval */
Manuel Pégourié-Gonnardfe34a5f2014-01-30 15:06:40 +0100125
Manuel Pégourié-Gonnard658dbed2014-01-30 19:03:45 +0100126 /* Callbacks */
Manuel Pégourié-Gonnardaf786ff2014-01-30 18:44:18 +0100127 int (*f_entropy)(void *, unsigned char *, size_t); /*!< entropy function */
128 void *p_entropy; /*!< context for the entropy function */
Manuel Pégourié-Gonnard0a4fb092015-05-07 12:50:31 +0100129
130#if defined(MBEDTLS_THREADING_C)
Gilles Peskineb5e295d2021-02-09 18:43:33 +0100131 /* Invariant: the mutex is initialized if and only if
132 * md_ctx->md_info != NULL. This means that the mutex is initialized
133 * during the initial seeding in mbedtls_hmac_drbg_seed() or
134 * mbedtls_hmac_drbg_seed_buf() and freed in mbedtls_ctr_drbg_free().
135 *
136 * Note that this invariant may change without notice. Do not rely on it
137 * and do not access the mutex directly in application code.
138 */
Manuel Pégourié-Gonnard0a4fb092015-05-07 12:50:31 +0100139 mbedtls_threading_mutex_t mutex;
140#endif
Manuel Pégourié-Gonnard2cf5a7c2015-04-08 12:49:31 +0200141} mbedtls_hmac_drbg_context;
Manuel Pégourié-Gonnard490bdf32014-01-27 14:03:10 +0100142
143/**
Gilles Peskinedb6f4142019-09-30 15:01:15 +0200144 * \brief HMAC_DRBG context initialization.
Manuel Pégourié-Gonnard490bdf32014-01-27 14:03:10 +0100145 *
Gilles Peskinedb6f4142019-09-30 15:01:15 +0200146 * This function makes the context ready for mbedtls_hmac_drbg_seed(),
147 * mbedtls_hmac_drbg_seed_buf() or mbedtls_hmac_drbg_free().
148 *
Gavin Acquroff77cb30c2020-03-01 17:06:11 -0800149 * \note The reseed interval is #MBEDTLS_HMAC_DRBG_RESEED_INTERVAL
150 * by default. Override this value by calling
151 * mbedtls_hmac_drbg_set_reseed_interval().
152 *
Gilles Peskinedb6f4142019-09-30 15:01:15 +0200153 * \param ctx HMAC_DRBG context to be initialized.
Manuel Pégourié-Gonnardf9e94812015-04-28 22:07:14 +0200154 */
155void mbedtls_hmac_drbg_init( mbedtls_hmac_drbg_context *ctx );
156
157/**
Gilles Peskinedb6f4142019-09-30 15:01:15 +0200158 * \brief HMAC_DRBG initial seeding.
Manuel Pégourié-Gonnardf9e94812015-04-28 22:07:14 +0200159 *
Gilles Peskinedb6f4142019-09-30 15:01:15 +0200160 * Set the initial seed and set up the entropy source for future reseeds.
161 *
Gilles Peskine0b5e8042019-09-30 15:20:52 +0200162 * A typical choice for the \p f_entropy and \p p_entropy parameters is
163 * to use the entropy module:
164 * - \p f_entropy is mbedtls_entropy_func();
165 * - \p p_entropy is an instance of ::mbedtls_entropy_context initialized
166 * with mbedtls_entropy_init() (which registers the platform's default
167 * entropy sources).
168 *
Gilles Peskine9fb45182019-10-01 18:39:45 +0200169 * You can provide a personalization string in addition to the
170 * entropy source, to make this instantiation as unique as possible.
171 *
Gilles Peskine0b5e8042019-09-30 15:20:52 +0200172 * \note By default, the security strength as defined by NIST is:
173 * - 128 bits if \p md_info is SHA-1;
174 * - 192 bits if \p md_info is SHA-224;
175 * - 256 bits if \p md_info is SHA-256, SHA-384 or SHA-512.
176 * Note that SHA-256 is just as efficient as SHA-224.
177 * The security strength can be reduced if a smaller
178 * entropy length is set with
Gilles Peskinec68b70c2019-10-04 11:47:35 +0200179 * mbedtls_hmac_drbg_set_entropy_len().
Gilles Peskine0b5e8042019-09-30 15:20:52 +0200180 *
Gilles Peskinec68b70c2019-10-04 11:47:35 +0200181 * \note The default entropy length is the security strength
182 * (converted from bits to bytes). You can override
183 * it by calling mbedtls_hmac_drbg_set_entropy_len().
Gilles Peskine0b5e8042019-09-30 15:20:52 +0200184 *
185 * \note During the initial seeding, this function calls
186 * the entropy source to obtain a nonce
187 * whose length is half the entropy length.
Gilles Peskinefb6876a2021-02-09 18:45:10 +0100188 */
189#if defined(MBEDTLS_THREADING_C)
190/**
191 * \note When Mbed TLS is built with threading support,
192 * after this function returns successfully,
193 * it is safe to call mbedtls_hmac_drbg_random()
194 * from multiple threads. Other operations, including
195 * reseeding, are not thread-safe.
196 */
197#endif /* MBEDTLS_THREADING_C */
198/**
Gilles Peskinedb6f4142019-09-30 15:01:15 +0200199 * \param ctx HMAC_DRBG context to be seeded.
200 * \param md_info MD algorithm to use for HMAC_DRBG.
201 * \param f_entropy The entropy callback, taking as arguments the
202 * \p p_entropy context, the buffer to fill, and the
203 * length of the buffer.
Gilles Peskine8b424392019-10-04 11:52:22 +0200204 * \p f_entropy is always called with a length that is
205 * less than or equal to the entropy length.
Gilles Peskinedb6f4142019-09-30 15:01:15 +0200206 * \param p_entropy The entropy context to pass to \p f_entropy.
Gilles Peskine9fb45182019-10-01 18:39:45 +0200207 * \param custom The personalization string.
208 * This can be \c NULL, in which case the personalization
209 * string is empty regardless of the value of \p len.
210 * \param len The length of the personalization string.
Gilles Peskinedb6f4142019-09-30 15:01:15 +0200211 * This must be at most #MBEDTLS_HMAC_DRBG_MAX_INPUT
212 * and also at most
213 * #MBEDTLS_HMAC_DRBG_MAX_SEED_INPUT - \p entropy_len * 3 / 2
214 * where \p entropy_len is the entropy length
Gilles Peskine0b5e8042019-09-30 15:20:52 +0200215 * described above.
Manuel Pégourié-Gonnard490bdf32014-01-27 14:03:10 +0100216 *
Gilles Peskine759c91d2019-10-01 18:30:02 +0200217 * \return \c 0 if successful.
Gilles Peskinedb6f4142019-09-30 15:01:15 +0200218 * \return #MBEDTLS_ERR_MD_BAD_INPUT_DATA if \p md_info is
219 * invalid.
220 * \return #MBEDTLS_ERR_MD_ALLOC_FAILED if there was not enough
221 * memory to allocate context data.
222 * \return #MBEDTLS_ERR_HMAC_DRBG_ENTROPY_SOURCE_FAILED
223 * if the call to \p f_entropy failed.
Manuel Pégourié-Gonnard490bdf32014-01-27 14:03:10 +0100224 */
Manuel Pégourié-Gonnardf9e94812015-04-28 22:07:14 +0200225int mbedtls_hmac_drbg_seed( mbedtls_hmac_drbg_context *ctx,
Manuel Pégourié-Gonnard2cf5a7c2015-04-08 12:49:31 +0200226 const mbedtls_md_info_t * md_info,
Manuel Pégourié-Gonnardfe34a5f2014-01-30 15:06:40 +0100227 int (*f_entropy)(void *, unsigned char *, size_t),
228 void *p_entropy,
229 const unsigned char *custom,
230 size_t len );
231
232/**
Manuel Pégourié-Gonnard4e669c62014-01-30 18:06:08 +0100233 * \brief Initilisation of simpified HMAC_DRBG (never reseeds).
Manuel Pégourié-Gonnardfe34a5f2014-01-30 15:06:40 +0100234 *
Gilles Peskinedb6f4142019-09-30 15:01:15 +0200235 * This function is meant for use in algorithms that need a pseudorandom
236 * input such as deterministic ECDSA.
Gilles Peskinefb6876a2021-02-09 18:45:10 +0100237 */
238#if defined(MBEDTLS_THREADING_C)
239/**
240 * \note When Mbed TLS is built with threading support,
241 * after this function returns successfully,
242 * it is safe to call mbedtls_hmac_drbg_random()
243 * from multiple threads. Other operations, including
244 * reseeding, are not thread-safe.
245 */
246#endif /* MBEDTLS_THREADING_C */
247/**
Gilles Peskinedb6f4142019-09-30 15:01:15 +0200248 * \param ctx HMAC_DRBG context to be initialised.
249 * \param md_info MD algorithm to use for HMAC_DRBG.
250 * \param data Concatenation of the initial entropy string and
251 * the additional data.
252 * \param data_len Length of \p data in bytes.
253 *
Gilles Peskine759c91d2019-10-01 18:30:02 +0200254 * \return \c 0 if successful. or
Gilles Peskinedb6f4142019-09-30 15:01:15 +0200255 * \return #MBEDTLS_ERR_MD_BAD_INPUT_DATA if \p md_info is
256 * invalid.
257 * \return #MBEDTLS_ERR_MD_ALLOC_FAILED if there was not enough
258 * memory to allocate context data.
Manuel Pégourié-Gonnardfe34a5f2014-01-30 15:06:40 +0100259 */
Manuel Pégourié-Gonnardf9e94812015-04-28 22:07:14 +0200260int mbedtls_hmac_drbg_seed_buf( mbedtls_hmac_drbg_context *ctx,
Manuel Pégourié-Gonnard2cf5a7c2015-04-08 12:49:31 +0200261 const mbedtls_md_info_t * md_info,
Manuel Pégourié-Gonnardfe34a5f2014-01-30 15:06:40 +0100262 const unsigned char *data, size_t data_len );
Manuel Pégourié-Gonnard490bdf32014-01-27 14:03:10 +0100263
264/**
Gilles Peskinedb6f4142019-09-30 15:01:15 +0200265 * \brief This function turns prediction resistance on or off.
266 * The default value is off.
Manuel Pégourié-Gonnardaf786ff2014-01-30 18:44:18 +0100267 *
Gilles Peskinedb6f4142019-09-30 15:01:15 +0200268 * \note If enabled, entropy is gathered at the beginning of
269 * every call to mbedtls_hmac_drbg_random_with_add()
270 * or mbedtls_hmac_drbg_random().
271 * Only use this if your entropy source has sufficient
272 * throughput.
Manuel Pégourié-Gonnardaf786ff2014-01-30 18:44:18 +0100273 *
Gilles Peskinedb6f4142019-09-30 15:01:15 +0200274 * \param ctx The HMAC_DRBG context.
275 * \param resistance #MBEDTLS_HMAC_DRBG_PR_ON or #MBEDTLS_HMAC_DRBG_PR_OFF.
Manuel Pégourié-Gonnardaf786ff2014-01-30 18:44:18 +0100276 */
Manuel Pégourié-Gonnard2cf5a7c2015-04-08 12:49:31 +0200277void mbedtls_hmac_drbg_set_prediction_resistance( mbedtls_hmac_drbg_context *ctx,
Manuel Pégourié-Gonnardaf786ff2014-01-30 18:44:18 +0100278 int resistance );
279
280/**
Gilles Peskinedb6f4142019-09-30 15:01:15 +0200281 * \brief This function sets the amount of entropy grabbed on each
Gilles Peskinec68b70c2019-10-04 11:47:35 +0200282 * seed or reseed.
Manuel Pégourié-Gonnard4e669c62014-01-30 18:06:08 +0100283 *
Gilles Peskinec68b70c2019-10-04 11:47:35 +0200284 * See the documentation of mbedtls_hmac_drbg_seed() for the default value.
Gilles Peskinedb6f4142019-09-30 15:01:15 +0200285 *
286 * \param ctx The HMAC_DRBG context.
287 * \param len The amount of entropy to grab, in bytes.
Manuel Pégourié-Gonnard4e669c62014-01-30 18:06:08 +0100288 */
Manuel Pégourié-Gonnard2cf5a7c2015-04-08 12:49:31 +0200289void mbedtls_hmac_drbg_set_entropy_len( mbedtls_hmac_drbg_context *ctx,
Manuel Pégourié-Gonnard4e669c62014-01-30 18:06:08 +0100290 size_t len );
291
292/**
Gilles Peskinedb6f4142019-09-30 15:01:15 +0200293 * \brief Set the reseed interval.
Manuel Pégourié-Gonnard658dbed2014-01-30 19:03:45 +0100294 *
Gilles Peskinedb6f4142019-09-30 15:01:15 +0200295 * The reseed interval is the number of calls to mbedtls_hmac_drbg_random()
296 * or mbedtls_hmac_drbg_random_with_add() after which the entropy function
297 * is called again.
298 *
299 * The default value is #MBEDTLS_HMAC_DRBG_RESEED_INTERVAL.
300 *
301 * \param ctx The HMAC_DRBG context.
302 * \param interval The reseed interval.
Manuel Pégourié-Gonnard658dbed2014-01-30 19:03:45 +0100303 */
Manuel Pégourié-Gonnard2cf5a7c2015-04-08 12:49:31 +0200304void mbedtls_hmac_drbg_set_reseed_interval( mbedtls_hmac_drbg_context *ctx,
Manuel Pégourié-Gonnard658dbed2014-01-30 19:03:45 +0100305 int interval );
306
307/**
Gilles Peskinedb6f4142019-09-30 15:01:15 +0200308 * \brief This function updates the state of the HMAC_DRBG context.
Manuel Pégourié-Gonnard490bdf32014-01-27 14:03:10 +0100309 *
Gilles Peskinefb6876a2021-02-09 18:45:10 +0100310 * \note This function is not thread-safe. It is not safe
311 * to call this function if another thread might be
312 * concurrently obtaining random numbers from the same
313 * context or updating or reseeding the same context.
314 *
Gilles Peskinedb6f4142019-09-30 15:01:15 +0200315 * \param ctx The HMAC_DRBG context.
316 * \param additional The data to update the state with.
Gilles Peskine759c91d2019-10-01 18:30:02 +0200317 * If this is \c NULL, there is no additional data.
Gilles Peskinedb6f4142019-09-30 15:01:15 +0200318 * \param add_len Length of \p additional in bytes.
Gilles Peskine759c91d2019-10-01 18:30:02 +0200319 * Unused if \p additional is \c NULL.
Manuel Pégourié-Gonnard490bdf32014-01-27 14:03:10 +0100320 *
Gilles Peskinee0e9c572018-09-11 16:47:16 +0200321 * \return \c 0 on success, or an error from the underlying
322 * hash calculation.
Manuel Pégourié-Gonnard490bdf32014-01-27 14:03:10 +0100323 */
Gilles Peskinee0e9c572018-09-11 16:47:16 +0200324int mbedtls_hmac_drbg_update_ret( mbedtls_hmac_drbg_context *ctx,
Manuel Pégourié-Gonnard490bdf32014-01-27 14:03:10 +0100325 const unsigned char *additional, size_t add_len );
326
327/**
Gilles Peskinedb6f4142019-09-30 15:01:15 +0200328 * \brief This function reseeds the HMAC_DRBG context, that is
329 * extracts data from the entropy source.
Manuel Pégourié-Gonnard8fc484d2014-01-30 18:28:09 +0100330 *
Gilles Peskinefb6876a2021-02-09 18:45:10 +0100331 * \note This function is not thread-safe. It is not safe
332 * to call this function if another thread might be
333 * concurrently obtaining random numbers from the same
334 * context or updating or reseeding the same context.
335 *
Gilles Peskinedb6f4142019-09-30 15:01:15 +0200336 * \param ctx The HMAC_DRBG context.
337 * \param additional Additional data to add to the state.
338 * If this is \c NULL, there is no additional data
339 * and \p len should be \c 0.
340 * \param len The length of the additional data.
341 * This must be at most #MBEDTLS_HMAC_DRBG_MAX_INPUT
342 * and also at most
343 * #MBEDTLS_HMAC_DRBG_MAX_SEED_INPUT - \p entropy_len
344 * where \p entropy_len is the entropy length
345 * (see mbedtls_hmac_drbg_set_entropy_len()).
Manuel Pégourié-Gonnard8fc484d2014-01-30 18:28:09 +0100346 *
Gilles Peskine759c91d2019-10-01 18:30:02 +0200347 * \return \c 0 if successful.
Gilles Peskinedb6f4142019-09-30 15:01:15 +0200348 * \return #MBEDTLS_ERR_HMAC_DRBG_ENTROPY_SOURCE_FAILED
349 * if a call to the entropy function failed.
Manuel Pégourié-Gonnard8fc484d2014-01-30 18:28:09 +0100350 */
Manuel Pégourié-Gonnard2cf5a7c2015-04-08 12:49:31 +0200351int mbedtls_hmac_drbg_reseed( mbedtls_hmac_drbg_context *ctx,
Manuel Pégourié-Gonnard8fc484d2014-01-30 18:28:09 +0100352 const unsigned char *additional, size_t len );
353
354/**
Gilles Peskinedb6f4142019-09-30 15:01:15 +0200355 * \brief This function updates an HMAC_DRBG instance with additional
356 * data and uses it to generate random data.
Manuel Pégourié-Gonnard8208d162014-01-30 12:19:26 +0100357 *
Gilles Peskine3f9c9732019-10-01 18:31:28 +0200358 * This function automatically reseeds if the reseed counter is exceeded
359 * or prediction resistance is enabled.
Manuel Pégourié-Gonnard8208d162014-01-30 12:19:26 +0100360 *
Gilles Peskinefb6876a2021-02-09 18:45:10 +0100361 * \note This function is not thread-safe. It is not safe
362 * to call this function if another thread might be
363 * concurrently obtaining random numbers from the same
364 * context or updating or reseeding the same context.
365 *
Gilles Peskinedb6f4142019-09-30 15:01:15 +0200366 * \param p_rng The HMAC_DRBG context. This must be a pointer to a
367 * #mbedtls_hmac_drbg_context structure.
368 * \param output The buffer to fill.
369 * \param output_len The length of the buffer in bytes.
370 * This must be at most #MBEDTLS_HMAC_DRBG_MAX_REQUEST.
371 * \param additional Additional data to update with.
Gilles Peskine759c91d2019-10-01 18:30:02 +0200372 * If this is \c NULL, there is no additional data
Gilles Peskinedb6f4142019-09-30 15:01:15 +0200373 * and \p add_len should be \c 0.
374 * \param add_len The length of the additional data.
375 * This must be at most #MBEDTLS_HMAC_DRBG_MAX_INPUT.
Manuel Pégourié-Gonnard8208d162014-01-30 12:19:26 +0100376 *
Gilles Peskinedb6f4142019-09-30 15:01:15 +0200377 * \return \c 0 if successful.
378 * \return #MBEDTLS_ERR_HMAC_DRBG_ENTROPY_SOURCE_FAILED
379 * if a call to the entropy source failed.
380 * \return #MBEDTLS_ERR_HMAC_DRBG_REQUEST_TOO_BIG if
381 * \p output_len > #MBEDTLS_HMAC_DRBG_MAX_REQUEST.
382 * \return #MBEDTLS_ERR_HMAC_DRBG_INPUT_TOO_BIG if
383 * \p add_len > #MBEDTLS_HMAC_DRBG_MAX_INPUT.
Manuel Pégourié-Gonnard8208d162014-01-30 12:19:26 +0100384 */
Manuel Pégourié-Gonnard2cf5a7c2015-04-08 12:49:31 +0200385int mbedtls_hmac_drbg_random_with_add( void *p_rng,
Manuel Pégourié-Gonnard8208d162014-01-30 12:19:26 +0100386 unsigned char *output, size_t output_len,
387 const unsigned char *additional,
388 size_t add_len );
389
390/**
Gilles Peskinedb6f4142019-09-30 15:01:15 +0200391 * \brief This function uses HMAC_DRBG to generate random data.
Manuel Pégourié-Gonnard490bdf32014-01-27 14:03:10 +0100392 *
Gilles Peskine3f9c9732019-10-01 18:31:28 +0200393 * This function automatically reseeds if the reseed counter is exceeded
394 * or prediction resistance is enabled.
Gilles Peskinefb6876a2021-02-09 18:45:10 +0100395 */
396#if defined(MBEDTLS_THREADING_C)
397/**
398 * \note When Mbed TLS is built with threading support,
399 * it is safe to call mbedtls_ctr_drbg_random()
400 * from multiple threads. Other operations, including
401 * reseeding, are not thread-safe.
402 */
403#endif /* MBEDTLS_THREADING_C */
404/**
Gilles Peskinedb6f4142019-09-30 15:01:15 +0200405 * \param p_rng The HMAC_DRBG context. This must be a pointer to a
406 * #mbedtls_hmac_drbg_context structure.
407 * \param output The buffer to fill.
408 * \param out_len The length of the buffer in bytes.
409 * This must be at most #MBEDTLS_HMAC_DRBG_MAX_REQUEST.
Manuel Pégourié-Gonnard490bdf32014-01-27 14:03:10 +0100410 *
Gilles Peskinedb6f4142019-09-30 15:01:15 +0200411 * \return \c 0 if successful.
412 * \return #MBEDTLS_ERR_HMAC_DRBG_ENTROPY_SOURCE_FAILED
413 * if a call to the entropy source failed.
414 * \return #MBEDTLS_ERR_HMAC_DRBG_REQUEST_TOO_BIG if
415 * \p out_len > #MBEDTLS_HMAC_DRBG_MAX_REQUEST.
Manuel Pégourié-Gonnard490bdf32014-01-27 14:03:10 +0100416 */
Manuel Pégourié-Gonnard2cf5a7c2015-04-08 12:49:31 +0200417int mbedtls_hmac_drbg_random( void *p_rng, unsigned char *output, size_t out_len );
Manuel Pégourié-Gonnard490bdf32014-01-27 14:03:10 +0100418
419/**
Gavin Acquroff77cb30c2020-03-01 17:06:11 -0800420 * \brief This function resets HMAC_DRBG context to the state immediately
421 * after initial call of mbedtls_hmac_drbg_init().
Manuel Pégourié-Gonnard490bdf32014-01-27 14:03:10 +0100422 *
Gilles Peskinedb6f4142019-09-30 15:01:15 +0200423 * \param ctx The HMAC_DRBG context to free.
Manuel Pégourié-Gonnard490bdf32014-01-27 14:03:10 +0100424 */
Manuel Pégourié-Gonnard2cf5a7c2015-04-08 12:49:31 +0200425void mbedtls_hmac_drbg_free( mbedtls_hmac_drbg_context *ctx );
Manuel Pégourié-Gonnard490bdf32014-01-27 14:03:10 +0100426
Gilles Peskinee0e9c572018-09-11 16:47:16 +0200427#if ! defined(MBEDTLS_DEPRECATED_REMOVED)
428#if defined(MBEDTLS_DEPRECATED_WARNING)
429#define MBEDTLS_DEPRECATED __attribute__((deprecated))
430#else
431#define MBEDTLS_DEPRECATED
432#endif
433/**
Gilles Peskinedb6f4142019-09-30 15:01:15 +0200434 * \brief This function updates the state of the HMAC_DRBG context.
Gilles Peskinee0e9c572018-09-11 16:47:16 +0200435 *
436 * \deprecated Superseded by mbedtls_hmac_drbg_update_ret()
437 * in 2.16.0.
438 *
Gilles Peskinedb6f4142019-09-30 15:01:15 +0200439 * \param ctx The HMAC_DRBG context.
440 * \param additional The data to update the state with.
Gilles Peskine759c91d2019-10-01 18:30:02 +0200441 * If this is \c NULL, there is no additional data.
Gilles Peskinedb6f4142019-09-30 15:01:15 +0200442 * \param add_len Length of \p additional in bytes.
Gilles Peskine759c91d2019-10-01 18:30:02 +0200443 * Unused if \p additional is \c NULL.
Gilles Peskinee0e9c572018-09-11 16:47:16 +0200444 */
445MBEDTLS_DEPRECATED void mbedtls_hmac_drbg_update(
446 mbedtls_hmac_drbg_context *ctx,
447 const unsigned char *additional, size_t add_len );
448#undef MBEDTLS_DEPRECATED
449#endif /* !MBEDTLS_DEPRECATED_REMOVED */
450
Manuel Pégourié-Gonnard2cf5a7c2015-04-08 12:49:31 +0200451#if defined(MBEDTLS_FS_IO)
Manuel Pégourié-Gonnard48bc3e82014-01-30 21:11:16 +0100452/**
Gilles Peskinedb6f4142019-09-30 15:01:15 +0200453 * \brief This function writes a seed file.
Manuel Pégourié-Gonnard48bc3e82014-01-30 21:11:16 +0100454 *
Gilles Peskinedb6f4142019-09-30 15:01:15 +0200455 * \param ctx The HMAC_DRBG context.
456 * \param path The name of the file.
Manuel Pégourié-Gonnard48bc3e82014-01-30 21:11:16 +0100457 *
Gilles Peskinedb6f4142019-09-30 15:01:15 +0200458 * \return \c 0 on success.
459 * \return #MBEDTLS_ERR_HMAC_DRBG_FILE_IO_ERROR on file error.
460 * \return #MBEDTLS_ERR_HMAC_DRBG_ENTROPY_SOURCE_FAILED on reseed
461 * failure.
Manuel Pégourié-Gonnard48bc3e82014-01-30 21:11:16 +0100462 */
Manuel Pégourié-Gonnard2cf5a7c2015-04-08 12:49:31 +0200463int mbedtls_hmac_drbg_write_seed_file( mbedtls_hmac_drbg_context *ctx, const char *path );
Manuel Pégourié-Gonnard48bc3e82014-01-30 21:11:16 +0100464
465/**
Gilles Peskinedb6f4142019-09-30 15:01:15 +0200466 * \brief This function reads and updates a seed file. The seed
467 * is added to this instance.
Manuel Pégourié-Gonnard48bc3e82014-01-30 21:11:16 +0100468 *
Gilles Peskinedb6f4142019-09-30 15:01:15 +0200469 * \param ctx The HMAC_DRBG context.
470 * \param path The name of the file.
Manuel Pégourié-Gonnard48bc3e82014-01-30 21:11:16 +0100471 *
Gilles Peskinedb6f4142019-09-30 15:01:15 +0200472 * \return \c 0 on success.
473 * \return #MBEDTLS_ERR_HMAC_DRBG_FILE_IO_ERROR on file error.
474 * \return #MBEDTLS_ERR_HMAC_DRBG_ENTROPY_SOURCE_FAILED on
475 * reseed failure.
476 * \return #MBEDTLS_ERR_HMAC_DRBG_INPUT_TOO_BIG if the existing
477 * seed file is too large.
Manuel Pégourié-Gonnard48bc3e82014-01-30 21:11:16 +0100478 */
Manuel Pégourié-Gonnard2cf5a7c2015-04-08 12:49:31 +0200479int mbedtls_hmac_drbg_update_seed_file( mbedtls_hmac_drbg_context *ctx, const char *path );
480#endif /* MBEDTLS_FS_IO */
Manuel Pégourié-Gonnard48bc3e82014-01-30 21:11:16 +0100481
Manuel Pégourié-Gonnard490bdf32014-01-27 14:03:10 +0100482
Manuel Pégourié-Gonnard2cf5a7c2015-04-08 12:49:31 +0200483#if defined(MBEDTLS_SELF_TEST)
Manuel Pégourié-Gonnard490bdf32014-01-27 14:03:10 +0100484/**
Gilles Peskinedb6f4142019-09-30 15:01:15 +0200485 * \brief The HMAC_DRBG Checkup routine.
Manuel Pégourié-Gonnard490bdf32014-01-27 14:03:10 +0100486 *
Gilles Peskinedb6f4142019-09-30 15:01:15 +0200487 * \return \c 0 if successful.
488 * \return \c 1 if the test failed.
Manuel Pégourié-Gonnard490bdf32014-01-27 14:03:10 +0100489 */
Manuel Pégourié-Gonnard2cf5a7c2015-04-08 12:49:31 +0200490int mbedtls_hmac_drbg_self_test( int verbose );
Manuel Pégourié-Gonnard490bdf32014-01-27 14:03:10 +0100491#endif
492
493#ifdef __cplusplus
494}
495#endif
496
497#endif /* hmac_drbg.h */