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Manuel Pégourié-Gonnard490bdf32014-01-27 14:03:10 +01001/**
2 * \file hmac_drbg.h
3 *
Gilles Peskine74efcd22019-09-30 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 Szépkúti1e148272020-08-07 13:07:28 +020011 * Copyright The Mbed TLS Contributors
Manuel Pégourié-Gonnard37ff1402015-09-04 14:21:07 +020012 * SPDX-License-Identifier: Apache-2.0
13 *
14 * Licensed under the Apache License, Version 2.0 (the "License"); you may
15 * not use this file except in compliance with the License.
16 * You may obtain a copy of the License at
17 *
18 * http://www.apache.org/licenses/LICENSE-2.0
19 *
20 * Unless required by applicable law or agreed to in writing, software
21 * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
22 * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
23 * See the License for the specific language governing permissions and
24 * limitations under the License.
Manuel Pégourié-Gonnard490bdf32014-01-27 14:03:10 +010025 */
Manuel Pégourié-Gonnard2cf5a7c2015-04-08 12:49:31 +020026#ifndef MBEDTLS_HMAC_DRBG_H
27#define MBEDTLS_HMAC_DRBG_H
Manuel Pégourié-Gonnard490bdf32014-01-27 14:03:10 +010028
Ron Eldor8b0cf2e2018-02-14 16:02:41 +020029#if !defined(MBEDTLS_CONFIG_FILE)
Jaeden Ameroc49fbbf2019-07-04 20:01:14 +010030#include "mbedtls/config.h"
Ron Eldor8b0cf2e2018-02-14 16:02:41 +020031#else
32#include MBEDTLS_CONFIG_FILE
33#endif
34
Jaeden Ameroc49fbbf2019-07-04 20:01:14 +010035#include "mbedtls/md.h"
Manuel Pégourié-Gonnard490bdf32014-01-27 14:03:10 +010036
Manuel Pégourié-Gonnard0a4fb092015-05-07 12:50:31 +010037#if defined(MBEDTLS_THREADING_C)
Jaeden Ameroc49fbbf2019-07-04 20:01:14 +010038#include "mbedtls/threading.h"
Manuel Pégourié-Gonnard0a4fb092015-05-07 12:50:31 +010039#endif
40
Manuel Pégourié-Gonnardfe34a5f2014-01-30 15:06:40 +010041/*
Manuel Pégourié-Gonnard9a6e93e2014-03-11 09:34:02 +010042 * Error codes
Manuel Pégourié-Gonnardfe34a5f2014-01-30 15:06:40 +010043 */
Manuel Pégourié-Gonnard2cf5a7c2015-04-08 12:49:31 +020044#define MBEDTLS_ERR_HMAC_DRBG_REQUEST_TOO_BIG -0x0003 /**< Too many random requested in single call. */
45#define MBEDTLS_ERR_HMAC_DRBG_INPUT_TOO_BIG -0x0005 /**< Input too large (Entropy + additional). */
46#define MBEDTLS_ERR_HMAC_DRBG_FILE_IO_ERROR -0x0007 /**< Read/write error in file. */
47#define MBEDTLS_ERR_HMAC_DRBG_ENTROPY_SOURCE_FAILED -0x0009 /**< The entropy source failed. */
Manuel Pégourié-Gonnardfe34a5f2014-01-30 15:06:40 +010048
Paul Bakker088c5c52014-04-25 11:11:10 +020049/**
50 * \name SECTION: Module settings
51 *
52 * The configuration options you can set for this module are in this section.
53 * Either change them in config.h or define them on the compiler command line.
54 * \{
55 */
56
Manuel Pégourié-Gonnard2cf5a7c2015-04-08 12:49:31 +020057#if !defined(MBEDTLS_HMAC_DRBG_RESEED_INTERVAL)
58#define MBEDTLS_HMAC_DRBG_RESEED_INTERVAL 10000 /**< Interval before reseed is performed by default */
Paul Bakker088c5c52014-04-25 11:11:10 +020059#endif
60
Manuel Pégourié-Gonnard2cf5a7c2015-04-08 12:49:31 +020061#if !defined(MBEDTLS_HMAC_DRBG_MAX_INPUT)
62#define MBEDTLS_HMAC_DRBG_MAX_INPUT 256 /**< Maximum number of additional input bytes */
Paul Bakker088c5c52014-04-25 11:11:10 +020063#endif
64
Manuel Pégourié-Gonnard2cf5a7c2015-04-08 12:49:31 +020065#if !defined(MBEDTLS_HMAC_DRBG_MAX_REQUEST)
66#define MBEDTLS_HMAC_DRBG_MAX_REQUEST 1024 /**< Maximum number of requested bytes per call */
Paul Bakker088c5c52014-04-25 11:11:10 +020067#endif
68
Manuel Pégourié-Gonnard2cf5a7c2015-04-08 12:49:31 +020069#if !defined(MBEDTLS_HMAC_DRBG_MAX_SEED_INPUT)
70#define MBEDTLS_HMAC_DRBG_MAX_SEED_INPUT 384 /**< Maximum size of (re)seed buffer */
Paul Bakker088c5c52014-04-25 11:11:10 +020071#endif
72
73/* \} name SECTION: Module settings */
Manuel Pégourié-Gonnardfe34a5f2014-01-30 15:06:40 +010074
Manuel Pégourié-Gonnard2cf5a7c2015-04-08 12:49:31 +020075#define MBEDTLS_HMAC_DRBG_PR_OFF 0 /**< No prediction resistance */
76#define MBEDTLS_HMAC_DRBG_PR_ON 1 /**< Prediction resistance enabled */
Manuel Pégourié-Gonnardaf786ff2014-01-30 18:44:18 +010077
Manuel Pégourié-Gonnard490bdf32014-01-27 14:03:10 +010078#ifdef __cplusplus
79extern "C" {
80#endif
81
Manuel Pégourié-Gonnardfe34a5f2014-01-30 15:06:40 +010082/**
83 * HMAC_DRBG context.
Manuel Pégourié-Gonnard490bdf32014-01-27 14:03:10 +010084 */
Dawid Drozd428cc522018-07-24 10:02:47 +020085typedef struct mbedtls_hmac_drbg_context
Manuel Pégourié-Gonnard490bdf32014-01-27 14:03:10 +010086{
Antonin Décimo36e89b52019-01-23 15:24:37 +010087 /* Working state: the key K is not stored explicitly,
Manuel Pégourié-Gonnardb05db2a2014-02-01 11:38:05 +010088 * but is implied by the HMAC context */
Manuel Pégourié-Gonnard2cf5a7c2015-04-08 12:49:31 +020089 mbedtls_md_context_t md_ctx; /*!< HMAC context (inc. K) */
90 unsigned char V[MBEDTLS_MD_MAX_SIZE]; /*!< V in the spec */
Manuel Pégourié-Gonnardb05db2a2014-02-01 11:38:05 +010091 int reseed_counter; /*!< reseed counter */
Manuel Pégourié-Gonnardfe34a5f2014-01-30 15:06:40 +010092
Manuel Pégourié-Gonnard658dbed2014-01-30 19:03:45 +010093 /* Administrative state */
Manuel Pégourié-Gonnardfe34a5f2014-01-30 15:06:40 +010094 size_t entropy_len; /*!< entropy bytes grabbed on each (re)seed */
Manuel Pégourié-Gonnardaf786ff2014-01-30 18:44:18 +010095 int prediction_resistance; /*!< enable prediction resistance (Automatic
96 reseed before every random generation) */
Manuel Pégourié-Gonnard658dbed2014-01-30 19:03:45 +010097 int reseed_interval; /*!< reseed interval */
Manuel Pégourié-Gonnardfe34a5f2014-01-30 15:06:40 +010098
Manuel Pégourié-Gonnard658dbed2014-01-30 19:03:45 +010099 /* Callbacks */
Manuel Pégourié-Gonnardaf786ff2014-01-30 18:44:18 +0100100 int (*f_entropy)(void *, unsigned char *, size_t); /*!< entropy function */
101 void *p_entropy; /*!< context for the entropy function */
Manuel Pégourié-Gonnard0a4fb092015-05-07 12:50:31 +0100102
103#if defined(MBEDTLS_THREADING_C)
Gilles Peskinee39b2192021-02-09 18:43:33 +0100104 /* Invariant: the mutex is initialized if and only if
105 * md_ctx->md_info != NULL. This means that the mutex is initialized
106 * during the initial seeding in mbedtls_hmac_drbg_seed() or
107 * mbedtls_hmac_drbg_seed_buf() and freed in mbedtls_ctr_drbg_free().
108 *
109 * Note that this invariant may change without notice. Do not rely on it
110 * and do not access the mutex directly in application code.
111 */
Manuel Pégourié-Gonnard0a4fb092015-05-07 12:50:31 +0100112 mbedtls_threading_mutex_t mutex;
113#endif
Manuel Pégourié-Gonnard2cf5a7c2015-04-08 12:49:31 +0200114} mbedtls_hmac_drbg_context;
Manuel Pégourié-Gonnard490bdf32014-01-27 14:03:10 +0100115
116/**
Gilles Peskine74efcd22019-09-30 15:01:15 +0200117 * \brief HMAC_DRBG context initialization.
Manuel Pégourié-Gonnard490bdf32014-01-27 14:03:10 +0100118 *
Gilles Peskine74efcd22019-09-30 15:01:15 +0200119 * This function makes the context ready for mbedtls_hmac_drbg_seed(),
120 * mbedtls_hmac_drbg_seed_buf() or mbedtls_hmac_drbg_free().
121 *
Gavin Acquroff6aceb512020-03-01 17:06:11 -0800122 * \note The reseed interval is #MBEDTLS_HMAC_DRBG_RESEED_INTERVAL
123 * by default. Override this value by calling
124 * mbedtls_hmac_drbg_set_reseed_interval().
125 *
Gilles Peskine74efcd22019-09-30 15:01:15 +0200126 * \param ctx HMAC_DRBG context to be initialized.
Manuel Pégourié-Gonnardf9e94812015-04-28 22:07:14 +0200127 */
128void mbedtls_hmac_drbg_init( mbedtls_hmac_drbg_context *ctx );
129
130/**
Gilles Peskine74efcd22019-09-30 15:01:15 +0200131 * \brief HMAC_DRBG initial seeding.
Manuel Pégourié-Gonnardf9e94812015-04-28 22:07:14 +0200132 *
Gilles Peskine74efcd22019-09-30 15:01:15 +0200133 * Set the initial seed and set up the entropy source for future reseeds.
134 *
Gilles Peskine3457b5e2019-09-30 15:20:52 +0200135 * A typical choice for the \p f_entropy and \p p_entropy parameters is
136 * to use the entropy module:
137 * - \p f_entropy is mbedtls_entropy_func();
138 * - \p p_entropy is an instance of ::mbedtls_entropy_context initialized
139 * with mbedtls_entropy_init() (which registers the platform's default
140 * entropy sources).
141 *
Gilles Peskine217b8152019-10-01 18:39:45 +0200142 * You can provide a personalization string in addition to the
143 * entropy source, to make this instantiation as unique as possible.
144 *
Gilles Peskine3457b5e2019-09-30 15:20:52 +0200145 * \note By default, the security strength as defined by NIST is:
146 * - 128 bits if \p md_info is SHA-1;
147 * - 192 bits if \p md_info is SHA-224;
148 * - 256 bits if \p md_info is SHA-256, SHA-384 or SHA-512.
149 * Note that SHA-256 is just as efficient as SHA-224.
150 * The security strength can be reduced if a smaller
151 * entropy length is set with
Gilles Peskine9d3baea2019-10-23 17:45:59 +0200152 * mbedtls_hmac_drbg_set_entropy_len().
Gilles Peskine3457b5e2019-09-30 15:20:52 +0200153 *
Gilles Peskine8f7921e2019-10-04 11:47:35 +0200154 * \note The default entropy length is the security strength
155 * (converted from bits to bytes). You can override
156 * it by calling mbedtls_hmac_drbg_set_entropy_len().
Gilles Peskine3457b5e2019-09-30 15:20:52 +0200157 *
158 * \note During the initial seeding, this function calls
159 * the entropy source to obtain a nonce
160 * whose length is half the entropy length.
161 *
Gilles Peskine74efcd22019-09-30 15:01:15 +0200162 * \param ctx HMAC_DRBG context to be seeded.
163 * \param md_info MD algorithm to use for HMAC_DRBG.
164 * \param f_entropy The entropy callback, taking as arguments the
165 * \p p_entropy context, the buffer to fill, and the
166 * length of the buffer.
Gilles Peskine77d44572019-10-04 11:52:22 +0200167 * \p f_entropy is always called with a length that is
168 * less than or equal to the entropy length.
Gilles Peskine74efcd22019-09-30 15:01:15 +0200169 * \param p_entropy The entropy context to pass to \p f_entropy.
Gilles Peskine217b8152019-10-01 18:39:45 +0200170 * \param custom The personalization string.
171 * This can be \c NULL, in which case the personalization
172 * string is empty regardless of the value of \p len.
173 * \param len The length of the personalization string.
Gilles Peskine74efcd22019-09-30 15:01:15 +0200174 * This must be at most #MBEDTLS_HMAC_DRBG_MAX_INPUT
175 * and also at most
176 * #MBEDTLS_HMAC_DRBG_MAX_SEED_INPUT - \p entropy_len * 3 / 2
177 * where \p entropy_len is the entropy length
Gilles Peskine3457b5e2019-09-30 15:20:52 +0200178 * described above.
Manuel Pégourié-Gonnard490bdf32014-01-27 14:03:10 +0100179 *
Gilles Peskine10f16ac2019-10-01 18:30:02 +0200180 * \return \c 0 if successful.
Gilles Peskine74efcd22019-09-30 15:01:15 +0200181 * \return #MBEDTLS_ERR_MD_BAD_INPUT_DATA if \p md_info is
182 * invalid.
183 * \return #MBEDTLS_ERR_MD_ALLOC_FAILED if there was not enough
184 * memory to allocate context data.
185 * \return #MBEDTLS_ERR_HMAC_DRBG_ENTROPY_SOURCE_FAILED
186 * if the call to \p f_entropy failed.
Manuel Pégourié-Gonnard490bdf32014-01-27 14:03:10 +0100187 */
Manuel Pégourié-Gonnardf9e94812015-04-28 22:07:14 +0200188int mbedtls_hmac_drbg_seed( mbedtls_hmac_drbg_context *ctx,
Manuel Pégourié-Gonnard2cf5a7c2015-04-08 12:49:31 +0200189 const mbedtls_md_info_t * md_info,
Manuel Pégourié-Gonnardfe34a5f2014-01-30 15:06:40 +0100190 int (*f_entropy)(void *, unsigned char *, size_t),
191 void *p_entropy,
192 const unsigned char *custom,
193 size_t len );
194
195/**
Manuel Pégourié-Gonnard4e669c62014-01-30 18:06:08 +0100196 * \brief Initilisation of simpified HMAC_DRBG (never reseeds).
Manuel Pégourié-Gonnardfe34a5f2014-01-30 15:06:40 +0100197 *
Gilles Peskine74efcd22019-09-30 15:01:15 +0200198 * This function is meant for use in algorithms that need a pseudorandom
199 * input such as deterministic ECDSA.
Manuel Pégourié-Gonnardfe34a5f2014-01-30 15:06:40 +0100200 *
Gilles Peskine74efcd22019-09-30 15:01:15 +0200201 * \param ctx HMAC_DRBG context to be initialised.
202 * \param md_info MD algorithm to use for HMAC_DRBG.
203 * \param data Concatenation of the initial entropy string and
204 * the additional data.
205 * \param data_len Length of \p data in bytes.
206 *
Gilles Peskine10f16ac2019-10-01 18:30:02 +0200207 * \return \c 0 if successful. or
Gilles Peskine74efcd22019-09-30 15:01:15 +0200208 * \return #MBEDTLS_ERR_MD_BAD_INPUT_DATA if \p md_info is
209 * invalid.
210 * \return #MBEDTLS_ERR_MD_ALLOC_FAILED if there was not enough
211 * memory to allocate context data.
Manuel Pégourié-Gonnardfe34a5f2014-01-30 15:06:40 +0100212 */
Manuel Pégourié-Gonnardf9e94812015-04-28 22:07:14 +0200213int mbedtls_hmac_drbg_seed_buf( mbedtls_hmac_drbg_context *ctx,
Manuel Pégourié-Gonnard2cf5a7c2015-04-08 12:49:31 +0200214 const mbedtls_md_info_t * md_info,
Manuel Pégourié-Gonnardfe34a5f2014-01-30 15:06:40 +0100215 const unsigned char *data, size_t data_len );
Manuel Pégourié-Gonnard490bdf32014-01-27 14:03:10 +0100216
217/**
Gilles Peskine74efcd22019-09-30 15:01:15 +0200218 * \brief This function turns prediction resistance on or off.
219 * The default value is off.
Manuel Pégourié-Gonnardaf786ff2014-01-30 18:44:18 +0100220 *
Gilles Peskine74efcd22019-09-30 15:01:15 +0200221 * \note If enabled, entropy is gathered at the beginning of
222 * every call to mbedtls_hmac_drbg_random_with_add()
223 * or mbedtls_hmac_drbg_random().
224 * Only use this if your entropy source has sufficient
225 * throughput.
Manuel Pégourié-Gonnardaf786ff2014-01-30 18:44:18 +0100226 *
Gilles Peskine74efcd22019-09-30 15:01:15 +0200227 * \param ctx The HMAC_DRBG context.
228 * \param resistance #MBEDTLS_HMAC_DRBG_PR_ON or #MBEDTLS_HMAC_DRBG_PR_OFF.
Manuel Pégourié-Gonnardaf786ff2014-01-30 18:44:18 +0100229 */
Manuel Pégourié-Gonnard2cf5a7c2015-04-08 12:49:31 +0200230void mbedtls_hmac_drbg_set_prediction_resistance( mbedtls_hmac_drbg_context *ctx,
Manuel Pégourié-Gonnardaf786ff2014-01-30 18:44:18 +0100231 int resistance );
232
233/**
Gilles Peskine74efcd22019-09-30 15:01:15 +0200234 * \brief This function sets the amount of entropy grabbed on each
Gilles Peskine9d3baea2019-10-23 17:45:59 +0200235 * seed or reseed.
Manuel Pégourié-Gonnard4e669c62014-01-30 18:06:08 +0100236 *
Gilles Peskine9d3baea2019-10-23 17:45:59 +0200237 * See the documentation of mbedtls_hmac_drbg_seed() for the default value.
Gilles Peskine74efcd22019-09-30 15:01:15 +0200238 *
239 * \param ctx The HMAC_DRBG context.
240 * \param len The amount of entropy to grab, in bytes.
Manuel Pégourié-Gonnard4e669c62014-01-30 18:06:08 +0100241 */
Manuel Pégourié-Gonnard2cf5a7c2015-04-08 12:49:31 +0200242void mbedtls_hmac_drbg_set_entropy_len( mbedtls_hmac_drbg_context *ctx,
Manuel Pégourié-Gonnard4e669c62014-01-30 18:06:08 +0100243 size_t len );
244
245/**
Gilles Peskine74efcd22019-09-30 15:01:15 +0200246 * \brief Set the reseed interval.
Manuel Pégourié-Gonnard658dbed2014-01-30 19:03:45 +0100247 *
Gilles Peskine74efcd22019-09-30 15:01:15 +0200248 * The reseed interval is the number of calls to mbedtls_hmac_drbg_random()
249 * or mbedtls_hmac_drbg_random_with_add() after which the entropy function
250 * is called again.
251 *
252 * The default value is #MBEDTLS_HMAC_DRBG_RESEED_INTERVAL.
253 *
254 * \param ctx The HMAC_DRBG context.
255 * \param interval The reseed interval.
Manuel Pégourié-Gonnard658dbed2014-01-30 19:03:45 +0100256 */
Manuel Pégourié-Gonnard2cf5a7c2015-04-08 12:49:31 +0200257void mbedtls_hmac_drbg_set_reseed_interval( mbedtls_hmac_drbg_context *ctx,
Manuel Pégourié-Gonnard658dbed2014-01-30 19:03:45 +0100258 int interval );
259
260/**
Gilles Peskine74efcd22019-09-30 15:01:15 +0200261 * \brief This function updates the state of the HMAC_DRBG context.
Manuel Pégourié-Gonnard490bdf32014-01-27 14:03:10 +0100262 *
Gilles Peskine74efcd22019-09-30 15:01:15 +0200263 * \param ctx The HMAC_DRBG context.
264 * \param additional The data to update the state with.
Gilles Peskine10f16ac2019-10-01 18:30:02 +0200265 * If this is \c NULL, there is no additional data.
Gilles Peskine74efcd22019-09-30 15:01:15 +0200266 * \param add_len Length of \p additional in bytes.
Gilles Peskine10f16ac2019-10-01 18:30:02 +0200267 * Unused if \p additional is \c NULL.
Manuel Pégourié-Gonnard490bdf32014-01-27 14:03:10 +0100268 *
Gilles Peskinee0e9c572018-09-11 16:47:16 +0200269 * \return \c 0 on success, or an error from the underlying
270 * hash calculation.
Manuel Pégourié-Gonnard490bdf32014-01-27 14:03:10 +0100271 */
Gilles Peskinee0e9c572018-09-11 16:47:16 +0200272int mbedtls_hmac_drbg_update_ret( mbedtls_hmac_drbg_context *ctx,
Manuel Pégourié-Gonnard490bdf32014-01-27 14:03:10 +0100273 const unsigned char *additional, size_t add_len );
274
275/**
Gilles Peskine74efcd22019-09-30 15:01:15 +0200276 * \brief This function reseeds the HMAC_DRBG context, that is
277 * extracts data from the entropy source.
Manuel Pégourié-Gonnard8fc484d2014-01-30 18:28:09 +0100278 *
Gilles Peskine74efcd22019-09-30 15:01:15 +0200279 * \param ctx The HMAC_DRBG context.
280 * \param additional Additional data to add to the state.
281 * If this is \c NULL, there is no additional data
282 * and \p len should be \c 0.
283 * \param len The length of the additional data.
284 * This must be at most #MBEDTLS_HMAC_DRBG_MAX_INPUT
285 * and also at most
286 * #MBEDTLS_HMAC_DRBG_MAX_SEED_INPUT - \p entropy_len
287 * where \p entropy_len is the entropy length
288 * (see mbedtls_hmac_drbg_set_entropy_len()).
Manuel Pégourié-Gonnard8fc484d2014-01-30 18:28:09 +0100289 *
Gilles Peskine10f16ac2019-10-01 18:30:02 +0200290 * \return \c 0 if successful.
Gilles Peskine74efcd22019-09-30 15:01:15 +0200291 * \return #MBEDTLS_ERR_HMAC_DRBG_ENTROPY_SOURCE_FAILED
292 * if a call to the entropy function failed.
Manuel Pégourié-Gonnard8fc484d2014-01-30 18:28:09 +0100293 */
Manuel Pégourié-Gonnard2cf5a7c2015-04-08 12:49:31 +0200294int mbedtls_hmac_drbg_reseed( mbedtls_hmac_drbg_context *ctx,
Manuel Pégourié-Gonnard8fc484d2014-01-30 18:28:09 +0100295 const unsigned char *additional, size_t len );
296
297/**
Gilles Peskine74efcd22019-09-30 15:01:15 +0200298 * \brief This function updates an HMAC_DRBG instance with additional
299 * data and uses it to generate random data.
Manuel Pégourié-Gonnard8208d162014-01-30 12:19:26 +0100300 *
Gilles Peskine2d8f0692019-10-01 18:31:28 +0200301 * This function automatically reseeds if the reseed counter is exceeded
302 * or prediction resistance is enabled.
Manuel Pégourié-Gonnard8208d162014-01-30 12:19:26 +0100303 *
Gilles Peskine74efcd22019-09-30 15:01:15 +0200304 * \param p_rng The HMAC_DRBG context. This must be a pointer to a
305 * #mbedtls_hmac_drbg_context structure.
306 * \param output The buffer to fill.
307 * \param output_len The length of the buffer in bytes.
308 * This must be at most #MBEDTLS_HMAC_DRBG_MAX_REQUEST.
309 * \param additional Additional data to update with.
Gilles Peskine10f16ac2019-10-01 18:30:02 +0200310 * If this is \c NULL, there is no additional data
Gilles Peskine74efcd22019-09-30 15:01:15 +0200311 * and \p add_len should be \c 0.
312 * \param add_len The length of the additional data.
313 * This must be at most #MBEDTLS_HMAC_DRBG_MAX_INPUT.
Manuel Pégourié-Gonnard8208d162014-01-30 12:19:26 +0100314 *
Gilles Peskine74efcd22019-09-30 15:01:15 +0200315 * \return \c 0 if successful.
316 * \return #MBEDTLS_ERR_HMAC_DRBG_ENTROPY_SOURCE_FAILED
317 * if a call to the entropy source failed.
318 * \return #MBEDTLS_ERR_HMAC_DRBG_REQUEST_TOO_BIG if
319 * \p output_len > #MBEDTLS_HMAC_DRBG_MAX_REQUEST.
320 * \return #MBEDTLS_ERR_HMAC_DRBG_INPUT_TOO_BIG if
321 * \p add_len > #MBEDTLS_HMAC_DRBG_MAX_INPUT.
Manuel Pégourié-Gonnard8208d162014-01-30 12:19:26 +0100322 */
Manuel Pégourié-Gonnard2cf5a7c2015-04-08 12:49:31 +0200323int mbedtls_hmac_drbg_random_with_add( void *p_rng,
Manuel Pégourié-Gonnard8208d162014-01-30 12:19:26 +0100324 unsigned char *output, size_t output_len,
325 const unsigned char *additional,
326 size_t add_len );
327
328/**
Gilles Peskine74efcd22019-09-30 15:01:15 +0200329 * \brief This function uses HMAC_DRBG to generate random data.
Manuel Pégourié-Gonnard490bdf32014-01-27 14:03:10 +0100330 *
Gilles Peskine2d8f0692019-10-01 18:31:28 +0200331 * This function automatically reseeds if the reseed counter is exceeded
332 * or prediction resistance is enabled.
Manuel Pégourié-Gonnard490bdf32014-01-27 14:03:10 +0100333 *
Gilles Peskine74efcd22019-09-30 15:01:15 +0200334 * \param p_rng The HMAC_DRBG context. This must be a pointer to a
335 * #mbedtls_hmac_drbg_context structure.
336 * \param output The buffer to fill.
337 * \param out_len The length of the buffer in bytes.
338 * This must be at most #MBEDTLS_HMAC_DRBG_MAX_REQUEST.
Manuel Pégourié-Gonnard490bdf32014-01-27 14:03:10 +0100339 *
Gilles Peskine74efcd22019-09-30 15:01:15 +0200340 * \return \c 0 if successful.
341 * \return #MBEDTLS_ERR_HMAC_DRBG_ENTROPY_SOURCE_FAILED
342 * if a call to the entropy source failed.
343 * \return #MBEDTLS_ERR_HMAC_DRBG_REQUEST_TOO_BIG if
344 * \p out_len > #MBEDTLS_HMAC_DRBG_MAX_REQUEST.
Manuel Pégourié-Gonnard490bdf32014-01-27 14:03:10 +0100345 */
Manuel Pégourié-Gonnard2cf5a7c2015-04-08 12:49:31 +0200346int mbedtls_hmac_drbg_random( void *p_rng, unsigned char *output, size_t out_len );
Manuel Pégourié-Gonnard490bdf32014-01-27 14:03:10 +0100347
348/**
Gavin Acquroff6aceb512020-03-01 17:06:11 -0800349 * \brief This function resets HMAC_DRBG context to the state immediately
350 * after initial call of mbedtls_hmac_drbg_init().
Manuel Pégourié-Gonnard490bdf32014-01-27 14:03:10 +0100351 *
Gilles Peskine74efcd22019-09-30 15:01:15 +0200352 * \param ctx The HMAC_DRBG context to free.
Manuel Pégourié-Gonnard490bdf32014-01-27 14:03:10 +0100353 */
Manuel Pégourié-Gonnard2cf5a7c2015-04-08 12:49:31 +0200354void mbedtls_hmac_drbg_free( mbedtls_hmac_drbg_context *ctx );
Manuel Pégourié-Gonnard490bdf32014-01-27 14:03:10 +0100355
Gilles Peskinee0e9c572018-09-11 16:47:16 +0200356#if ! defined(MBEDTLS_DEPRECATED_REMOVED)
357#if defined(MBEDTLS_DEPRECATED_WARNING)
358#define MBEDTLS_DEPRECATED __attribute__((deprecated))
359#else
360#define MBEDTLS_DEPRECATED
361#endif
362/**
Gilles Peskine74efcd22019-09-30 15:01:15 +0200363 * \brief This function updates the state of the HMAC_DRBG context.
Gilles Peskinee0e9c572018-09-11 16:47:16 +0200364 *
365 * \deprecated Superseded by mbedtls_hmac_drbg_update_ret()
366 * in 2.16.0.
367 *
Gilles Peskine74efcd22019-09-30 15:01:15 +0200368 * \param ctx The HMAC_DRBG context.
369 * \param additional The data to update the state with.
Gilles Peskine10f16ac2019-10-01 18:30:02 +0200370 * If this is \c NULL, there is no additional data.
Gilles Peskine74efcd22019-09-30 15:01:15 +0200371 * \param add_len Length of \p additional in bytes.
Gilles Peskine10f16ac2019-10-01 18:30:02 +0200372 * Unused if \p additional is \c NULL.
Gilles Peskinee0e9c572018-09-11 16:47:16 +0200373 */
374MBEDTLS_DEPRECATED void mbedtls_hmac_drbg_update(
375 mbedtls_hmac_drbg_context *ctx,
376 const unsigned char *additional, size_t add_len );
377#undef MBEDTLS_DEPRECATED
378#endif /* !MBEDTLS_DEPRECATED_REMOVED */
379
Manuel Pégourié-Gonnard2cf5a7c2015-04-08 12:49:31 +0200380#if defined(MBEDTLS_FS_IO)
Manuel Pégourié-Gonnard48bc3e82014-01-30 21:11:16 +0100381/**
Gilles Peskine74efcd22019-09-30 15:01:15 +0200382 * \brief This function writes a seed file.
Manuel Pégourié-Gonnard48bc3e82014-01-30 21:11:16 +0100383 *
Gilles Peskine74efcd22019-09-30 15:01:15 +0200384 * \param ctx The HMAC_DRBG context.
385 * \param path The name of the file.
Manuel Pégourié-Gonnard48bc3e82014-01-30 21:11:16 +0100386 *
Gilles Peskine74efcd22019-09-30 15:01:15 +0200387 * \return \c 0 on success.
388 * \return #MBEDTLS_ERR_HMAC_DRBG_FILE_IO_ERROR on file error.
389 * \return #MBEDTLS_ERR_HMAC_DRBG_ENTROPY_SOURCE_FAILED on reseed
390 * failure.
Manuel Pégourié-Gonnard48bc3e82014-01-30 21:11:16 +0100391 */
Manuel Pégourié-Gonnard2cf5a7c2015-04-08 12:49:31 +0200392int mbedtls_hmac_drbg_write_seed_file( mbedtls_hmac_drbg_context *ctx, const char *path );
Manuel Pégourié-Gonnard48bc3e82014-01-30 21:11:16 +0100393
394/**
Gilles Peskine74efcd22019-09-30 15:01:15 +0200395 * \brief This function reads and updates a seed file. The seed
396 * is added to this instance.
Manuel Pégourié-Gonnard48bc3e82014-01-30 21:11:16 +0100397 *
Gilles Peskine74efcd22019-09-30 15:01:15 +0200398 * \param ctx The HMAC_DRBG context.
399 * \param path The name of the file.
Manuel Pégourié-Gonnard48bc3e82014-01-30 21:11:16 +0100400 *
Gilles Peskine74efcd22019-09-30 15:01:15 +0200401 * \return \c 0 on success.
402 * \return #MBEDTLS_ERR_HMAC_DRBG_FILE_IO_ERROR on file error.
403 * \return #MBEDTLS_ERR_HMAC_DRBG_ENTROPY_SOURCE_FAILED on
404 * reseed failure.
405 * \return #MBEDTLS_ERR_HMAC_DRBG_INPUT_TOO_BIG if the existing
406 * seed file is too large.
Manuel Pégourié-Gonnard48bc3e82014-01-30 21:11:16 +0100407 */
Manuel Pégourié-Gonnard2cf5a7c2015-04-08 12:49:31 +0200408int mbedtls_hmac_drbg_update_seed_file( mbedtls_hmac_drbg_context *ctx, const char *path );
409#endif /* MBEDTLS_FS_IO */
Manuel Pégourié-Gonnard48bc3e82014-01-30 21:11:16 +0100410
Manuel Pégourié-Gonnard490bdf32014-01-27 14:03:10 +0100411
Manuel Pégourié-Gonnard2cf5a7c2015-04-08 12:49:31 +0200412#if defined(MBEDTLS_SELF_TEST)
Manuel Pégourié-Gonnard490bdf32014-01-27 14:03:10 +0100413/**
Gilles Peskine74efcd22019-09-30 15:01:15 +0200414 * \brief The HMAC_DRBG Checkup routine.
Manuel Pégourié-Gonnard490bdf32014-01-27 14:03:10 +0100415 *
Gilles Peskine74efcd22019-09-30 15:01:15 +0200416 * \return \c 0 if successful.
417 * \return \c 1 if the test failed.
Manuel Pégourié-Gonnard490bdf32014-01-27 14:03:10 +0100418 */
Manuel Pégourié-Gonnard2cf5a7c2015-04-08 12:49:31 +0200419int mbedtls_hmac_drbg_self_test( int verbose );
Manuel Pégourié-Gonnard490bdf32014-01-27 14:03:10 +0100420#endif
421
422#ifdef __cplusplus
423}
424#endif
425
426#endif /* hmac_drbg.h */