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0de8e387 | 1 | /** |
2 | * \file hmac_drbg.h | |
3 | * | |
4 | * \brief HMAC_DRBG (NIST SP 800-90A) | |
5 | * | |
6 | * Copyright (C) 2014, ARM Limited, All Rights Reserved | |
7 | * | |
8 | * This file is part of mbed TLS (https://tls.mbed.org) | |
9 | * | |
10 | * This program is free software; you can redistribute it and/or modify | |
11 | * it under the terms of the GNU General Public License as published by | |
12 | * the Free Software Foundation; either version 2 of the License, or | |
13 | * (at your option) any later version. | |
14 | * | |
15 | * This program is distributed in the hope that it will be useful, | |
16 | * but WITHOUT ANY WARRANTY; without even the implied warranty of | |
17 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
18 | * GNU General Public License for more details. | |
19 | * | |
20 | * You should have received a copy of the GNU General Public License along | |
21 | * with this program; if not, write to the Free Software Foundation, Inc., | |
22 | * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA. | |
23 | */ | |
24 | #ifndef MBEDTLS_HMAC_DRBG_H | |
25 | #define MBEDTLS_HMAC_DRBG_H | |
26 | ||
27 | #include "md.h" | |
28 | ||
29 | #if defined(MBEDTLS_THREADING_C) | |
30 | #include "mbedtls/threading.h" | |
31 | #endif | |
32 | ||
33 | /* | |
34 | * Error codes | |
35 | */ | |
36 | #define MBEDTLS_ERR_HMAC_DRBG_REQUEST_TOO_BIG -0x0003 /**< Too many random requested in single call. */ | |
37 | #define MBEDTLS_ERR_HMAC_DRBG_INPUT_TOO_BIG -0x0005 /**< Input too large (Entropy + additional). */ | |
38 | #define MBEDTLS_ERR_HMAC_DRBG_FILE_IO_ERROR -0x0007 /**< Read/write error in file. */ | |
39 | #define MBEDTLS_ERR_HMAC_DRBG_ENTROPY_SOURCE_FAILED -0x0009 /**< The entropy source failed. */ | |
40 | ||
41 | /** | |
42 | * \name SECTION: Module settings | |
43 | * | |
44 | * The configuration options you can set for this module are in this section. | |
45 | * Either change them in config.h or define them on the compiler command line. | |
46 | * \{ | |
47 | */ | |
48 | ||
49 | #if !defined(MBEDTLS_HMAC_DRBG_RESEED_INTERVAL) | |
50 | #define MBEDTLS_HMAC_DRBG_RESEED_INTERVAL 10000 /**< Interval before reseed is performed by default */ | |
51 | #endif | |
52 | ||
53 | #if !defined(MBEDTLS_HMAC_DRBG_MAX_INPUT) | |
54 | #define MBEDTLS_HMAC_DRBG_MAX_INPUT 256 /**< Maximum number of additional input bytes */ | |
55 | #endif | |
56 | ||
57 | #if !defined(MBEDTLS_HMAC_DRBG_MAX_REQUEST) | |
58 | #define MBEDTLS_HMAC_DRBG_MAX_REQUEST 1024 /**< Maximum number of requested bytes per call */ | |
59 | #endif | |
60 | ||
61 | #if !defined(MBEDTLS_HMAC_DRBG_MAX_SEED_INPUT) | |
62 | #define MBEDTLS_HMAC_DRBG_MAX_SEED_INPUT 384 /**< Maximum size of (re)seed buffer */ | |
63 | #endif | |
64 | ||
65 | /* \} name SECTION: Module settings */ | |
66 | ||
67 | #define MBEDTLS_HMAC_DRBG_PR_OFF 0 /**< No prediction resistance */ | |
68 | #define MBEDTLS_HMAC_DRBG_PR_ON 1 /**< Prediction resistance enabled */ | |
69 | ||
70 | #ifdef __cplusplus | |
71 | extern "C" { | |
72 | #endif | |
73 | ||
74 | /** | |
75 | * HMAC_DRBG context. | |
76 | */ | |
77 | typedef struct | |
78 | { | |
79 | /* Working state: the key K is not stored explicitely, | |
80 | * but is implied by the HMAC context */ | |
81 | mbedtls_md_context_t md_ctx; /*!< HMAC context (inc. K) */ | |
82 | unsigned char V[MBEDTLS_MD_MAX_SIZE]; /*!< V in the spec */ | |
83 | int reseed_counter; /*!< reseed counter */ | |
84 | ||
85 | /* Administrative state */ | |
86 | size_t entropy_len; /*!< entropy bytes grabbed on each (re)seed */ | |
87 | int prediction_resistance; /*!< enable prediction resistance (Automatic | |
88 | reseed before every random generation) */ | |
89 | int reseed_interval; /*!< reseed interval */ | |
90 | ||
91 | /* Callbacks */ | |
92 | int (*f_entropy)(void *, unsigned char *, size_t); /*!< entropy function */ | |
93 | void *p_entropy; /*!< context for the entropy function */ | |
94 | ||
95 | #if defined(MBEDTLS_THREADING_C) | |
96 | mbedtls_threading_mutex_t mutex; | |
97 | #endif | |
98 | } mbedtls_hmac_drbg_context; | |
99 | ||
100 | /** | |
101 | * \brief HMAC_DRBG context initialization | |
102 | * Makes the context ready for mbetls_hmac_drbg_seed(), | |
103 | * mbedtls_hmac_drbg_seed_buf() or | |
104 | * mbedtls_hmac_drbg_free(). | |
105 | * | |
106 | * \param ctx HMAC_DRBG context to be initialized | |
107 | */ | |
108 | void mbedtls_hmac_drbg_init( mbedtls_hmac_drbg_context *ctx ); | |
109 | ||
110 | /** | |
111 | * \brief HMAC_DRBG initial seeding | |
112 | * Seed and setup entropy source for future reseeds. | |
113 | * | |
114 | * \param ctx HMAC_DRBG context to be seeded | |
115 | * \param md_info MD algorithm to use for HMAC_DRBG | |
116 | * \param f_entropy Entropy callback (p_entropy, buffer to fill, buffer | |
117 | * length) | |
118 | * \param p_entropy Entropy context | |
119 | * \param custom Personalization data (Device specific identifiers) | |
120 | * (Can be NULL) | |
121 | * \param len Length of personalization data | |
122 | * | |
123 | * \note The "security strength" as defined by NIST is set to: | |
124 | * 128 bits if md_alg is SHA-1, | |
125 | * 192 bits if md_alg is SHA-224, | |
126 | * 256 bits if md_alg is SHA-256 or higher. | |
127 | * Note that SHA-256 is just as efficient as SHA-224. | |
128 | * | |
129 | * \return 0 if successful, or | |
130 | * MBEDTLS_ERR_MD_BAD_INPUT_DATA, or | |
131 | * MBEDTLS_ERR_MD_ALLOC_FAILED, or | |
132 | * MBEDTLS_ERR_HMAC_DRBG_ENTROPY_SOURCE_FAILED. | |
133 | */ | |
134 | int mbedtls_hmac_drbg_seed( mbedtls_hmac_drbg_context *ctx, | |
135 | const mbedtls_md_info_t * md_info, | |
136 | int (*f_entropy)(void *, unsigned char *, size_t), | |
137 | void *p_entropy, | |
138 | const unsigned char *custom, | |
139 | size_t len ); | |
140 | ||
141 | /** | |
142 | * \brief Initilisation of simpified HMAC_DRBG (never reseeds). | |
143 | * (For use with deterministic ECDSA.) | |
144 | * | |
145 | * \param ctx HMAC_DRBG context to be initialised | |
146 | * \param md_info MD algorithm to use for HMAC_DRBG | |
147 | * \param data Concatenation of entropy string and additional data | |
148 | * \param data_len Length of data in bytes | |
149 | * | |
150 | * \return 0 if successful, or | |
151 | * MBEDTLS_ERR_MD_BAD_INPUT_DATA, or | |
152 | * MBEDTLS_ERR_MD_ALLOC_FAILED. | |
153 | */ | |
154 | int mbedtls_hmac_drbg_seed_buf( mbedtls_hmac_drbg_context *ctx, | |
155 | const mbedtls_md_info_t * md_info, | |
156 | const unsigned char *data, size_t data_len ); | |
157 | ||
158 | /** | |
159 | * \brief Enable / disable prediction resistance (Default: Off) | |
160 | * | |
161 | * Note: If enabled, entropy is used for ctx->entropy_len before each call! | |
162 | * Only use this if you have ample supply of good entropy! | |
163 | * | |
164 | * \param ctx HMAC_DRBG context | |
165 | * \param resistance MBEDTLS_HMAC_DRBG_PR_ON or MBEDTLS_HMAC_DRBG_PR_OFF | |
166 | */ | |
167 | void mbedtls_hmac_drbg_set_prediction_resistance( mbedtls_hmac_drbg_context *ctx, | |
168 | int resistance ); | |
169 | ||
170 | /** | |
171 | * \brief Set the amount of entropy grabbed on each reseed | |
172 | * (Default: given by the security strength, which | |
173 | * depends on the hash used, see \c mbedtls_hmac_drbg_init() ) | |
174 | * | |
175 | * \param ctx HMAC_DRBG context | |
176 | * \param len Amount of entropy to grab, in bytes | |
177 | */ | |
178 | void mbedtls_hmac_drbg_set_entropy_len( mbedtls_hmac_drbg_context *ctx, | |
179 | size_t len ); | |
180 | ||
181 | /** | |
182 | * \brief Set the reseed interval | |
183 | * (Default: MBEDTLS_HMAC_DRBG_RESEED_INTERVAL) | |
184 | * | |
185 | * \param ctx HMAC_DRBG context | |
186 | * \param interval Reseed interval | |
187 | */ | |
188 | void mbedtls_hmac_drbg_set_reseed_interval( mbedtls_hmac_drbg_context *ctx, | |
189 | int interval ); | |
190 | ||
191 | /** | |
192 | * \brief HMAC_DRBG update state | |
193 | * | |
194 | * \param ctx HMAC_DRBG context | |
195 | * \param additional Additional data to update state with, or NULL | |
196 | * \param add_len Length of additional data, or 0 | |
197 | * | |
198 | * \note Additional data is optional, pass NULL and 0 as second | |
199 | * third argument if no additional data is being used. | |
200 | */ | |
201 | void mbedtls_hmac_drbg_update( mbedtls_hmac_drbg_context *ctx, | |
202 | const unsigned char *additional, size_t add_len ); | |
203 | ||
204 | /** | |
205 | * \brief HMAC_DRBG reseeding (extracts data from entropy source) | |
206 | * | |
207 | * \param ctx HMAC_DRBG context | |
208 | * \param additional Additional data to add to state (Can be NULL) | |
209 | * \param len Length of additional data | |
210 | * | |
211 | * \return 0 if successful, or | |
212 | * MBEDTLS_ERR_HMAC_DRBG_ENTROPY_SOURCE_FAILED | |
213 | */ | |
214 | int mbedtls_hmac_drbg_reseed( mbedtls_hmac_drbg_context *ctx, | |
215 | const unsigned char *additional, size_t len ); | |
216 | ||
217 | /** | |
218 | * \brief HMAC_DRBG generate random with additional update input | |
219 | * | |
220 | * Note: Automatically reseeds if reseed_counter is reached or PR is enabled. | |
221 | * | |
222 | * \param p_rng HMAC_DRBG context | |
223 | * \param output Buffer to fill | |
224 | * \param output_len Length of the buffer | |
225 | * \param additional Additional data to update with (can be NULL) | |
226 | * \param add_len Length of additional data (can be 0) | |
227 | * | |
228 | * \return 0 if successful, or | |
229 | * MBEDTLS_ERR_HMAC_DRBG_ENTROPY_SOURCE_FAILED, or | |
230 | * MBEDTLS_ERR_HMAC_DRBG_REQUEST_TOO_BIG, or | |
231 | * MBEDTLS_ERR_HMAC_DRBG_INPUT_TOO_BIG. | |
232 | */ | |
233 | int mbedtls_hmac_drbg_random_with_add( void *p_rng, | |
234 | unsigned char *output, size_t output_len, | |
235 | const unsigned char *additional, | |
236 | size_t add_len ); | |
237 | ||
238 | /** | |
239 | * \brief HMAC_DRBG generate random | |
240 | * | |
241 | * Note: Automatically reseeds if reseed_counter is reached or PR is enabled. | |
242 | * | |
243 | * \param p_rng HMAC_DRBG context | |
244 | * \param output Buffer to fill | |
245 | * \param out_len Length of the buffer | |
246 | * | |
247 | * \return 0 if successful, or | |
248 | * MBEDTLS_ERR_HMAC_DRBG_ENTROPY_SOURCE_FAILED, or | |
249 | * MBEDTLS_ERR_HMAC_DRBG_REQUEST_TOO_BIG | |
250 | */ | |
251 | int mbedtls_hmac_drbg_random( void *p_rng, unsigned char *output, size_t out_len ); | |
252 | ||
253 | /** | |
254 | * \brief Free an HMAC_DRBG context | |
255 | * | |
256 | * \param ctx HMAC_DRBG context to free. | |
257 | */ | |
258 | void mbedtls_hmac_drbg_free( mbedtls_hmac_drbg_context *ctx ); | |
259 | ||
260 | #if defined(MBEDTLS_FS_IO) | |
261 | /** | |
262 | * \brief Write a seed file | |
263 | * | |
264 | * \param ctx HMAC_DRBG context | |
265 | * \param path Name of the file | |
266 | * | |
267 | * \return 0 if successful, 1 on file error, or | |
268 | * MBEDTLS_ERR_HMAC_DRBG_ENTROPY_SOURCE_FAILED | |
269 | */ | |
270 | int mbedtls_hmac_drbg_write_seed_file( mbedtls_hmac_drbg_context *ctx, const char *path ); | |
271 | ||
272 | /** | |
273 | * \brief Read and update a seed file. Seed is added to this | |
274 | * instance | |
275 | * | |
276 | * \param ctx HMAC_DRBG context | |
277 | * \param path Name of the file | |
278 | * | |
279 | * \return 0 if successful, 1 on file error, | |
280 | * MBEDTLS_ERR_HMAC_DRBG_ENTROPY_SOURCE_FAILED or | |
281 | * MBEDTLS_ERR_HMAC_DRBG_INPUT_TOO_BIG | |
282 | */ | |
283 | int mbedtls_hmac_drbg_update_seed_file( mbedtls_hmac_drbg_context *ctx, const char *path ); | |
284 | #endif /* MBEDTLS_FS_IO */ | |
285 | ||
286 | ||
287 | #if defined(MBEDTLS_SELF_TEST) | |
288 | /** | |
289 | * \brief Checkup routine | |
290 | * | |
291 | * \return 0 if successful, or 1 if the test failed | |
292 | */ | |
293 | int mbedtls_hmac_drbg_self_test( int verbose ); | |
294 | #endif | |
295 | ||
296 | #ifdef __cplusplus | |
297 | } | |
298 | #endif | |
299 | ||
300 | #endif /* hmac_drbg.h */ |