2 * Copyright (C) 2012 Michael Brown <mbrown@fensystems.co.uk>.
4 * This program is free software; you can redistribute it and/or
5 * modify it under the terms of the GNU General Public License as
6 * published by the Free Software Foundation; either version 2 of the
7 * License, or any later version.
9 * This program is distributed in the hope that it will be useful, but
10 * WITHOUT ANY WARRANTY; without even the implied warranty of
11 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
12 * General Public License for more details.
14 * You should have received a copy of the GNU General Public License
15 * along with this program; if not, write to the Free Software
16 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
19 * You can also choose to distribute this program under the terms of
20 * the Unmodified Binary Distribution Licence (as given in the file
21 * COPYING.UBDL), provided that you have satisfied its requirements.
24 FILE_LICENCE ( GPL2_OR_LATER_OR_UBDL
);
30 * This algorithm is designed to comply with ANS X9.82 Part 3-2007
31 * Section 10.2.2.2. This standard is not freely available, but most
32 * of the text appears to be shared with NIST SP 800-90, which can be
35 * http://csrc.nist.gov/publications/nistpubs/800-90/SP800-90revised_March2007.pdf
37 * Where possible, references are given to both documents. In the
38 * case of any disagreement, ANS X9.82 takes priority over NIST SP
39 * 800-90. (In particular, note that some algorithms that are
40 * Approved by NIST SP 800-90 are not Approved by ANS X9.82.)
47 #include <ipxe/crypto.h>
48 #include <ipxe/hmac.h>
49 #include <ipxe/hmac_drbg.h>
52 * Update the HMAC_DRBG key
54 * @v hash Underlying hash algorithm
55 * @v state HMAC_DRBG internal state
56 * @v data Provided data
57 * @v len Length of provided data
58 * @v single Single byte used in concatenation
60 * This function carries out the operation
62 * K = HMAC ( K, V || single || provided_data )
64 * as used by hmac_drbg_update()
66 static void hmac_drbg_update_key ( struct digest_algorithm
*hash
,
67 struct hmac_drbg_state
*state
,
68 const void *data
, size_t len
,
69 const uint8_t single
) {
70 uint8_t context
[ hash
->ctxsize
];
71 size_t out_len
= hash
->digestsize
;
73 DBGC ( state
, "HMAC_DRBG_%s %p provided data :\n", hash
->name
, state
);
74 DBGC_HDA ( state
, 0, data
, len
);
77 assert ( hash
!= NULL
);
78 assert ( state
!= NULL
);
79 assert ( ( data
!= NULL
) || ( len
== 0 ) );
80 assert ( ( single
== 0x00 ) || ( single
== 0x01 ) );
82 /* K = HMAC ( K, V || single || provided_data ) */
83 hmac_init ( hash
, context
, state
->key
, &out_len
);
84 assert ( out_len
== hash
->digestsize
);
85 hmac_update ( hash
, context
, state
->value
, out_len
);
86 hmac_update ( hash
, context
, &single
, sizeof ( single
) );
87 hmac_update ( hash
, context
, data
, len
);
88 hmac_final ( hash
, context
, state
->key
, &out_len
, state
->key
);
89 assert ( out_len
== hash
->digestsize
);
91 DBGC ( state
, "HMAC_DRBG_%s %p K = HMAC ( K, V || %#02x || "
92 "provided_data ) :\n", hash
->name
, state
, single
);
93 DBGC_HDA ( state
, 0, state
->key
, out_len
);
97 * Update the HMAC_DRBG value
99 * @v hash Underlying hash algorithm
100 * @v state HMAC_DRBG internal state
101 * @v data Provided data
102 * @v len Length of provided data
103 * @v single Single byte used in concatenation
105 * This function carries out the operation
109 * as used by hmac_drbg_update() and hmac_drbg_generate()
111 static void hmac_drbg_update_value ( struct digest_algorithm
*hash
,
112 struct hmac_drbg_state
*state
) {
113 uint8_t context
[ hash
->ctxsize
];
114 size_t out_len
= hash
->digestsize
;
117 assert ( hash
!= NULL
);
118 assert ( state
!= NULL
);
120 /* V = HMAC ( K, V ) */
121 hmac_init ( hash
, context
, state
->key
, &out_len
);
122 assert ( out_len
== hash
->digestsize
);
123 hmac_update ( hash
, context
, state
->value
, out_len
);
124 hmac_final ( hash
, context
, state
->key
, &out_len
, state
->value
);
125 assert ( out_len
== hash
->digestsize
);
127 DBGC ( state
, "HMAC_DRBG_%s %p V = HMAC ( K, V ) :\n",
129 DBGC_HDA ( state
, 0, state
->value
, out_len
);
133 * Update HMAC_DRBG internal state
135 * @v hash Underlying hash algorithm
136 * @v state HMAC_DRBG internal state
137 * @v data Provided data
138 * @v len Length of provided data
140 * This is the HMAC_DRBG_Update function defined in ANS X9.82 Part
141 * 3-2007 Section 10.2.2.2.2 (NIST SP 800-90 Section 10.1.2.2).
143 * The key and value are updated in-place within the HMAC_DRBG
146 static void hmac_drbg_update ( struct digest_algorithm
*hash
,
147 struct hmac_drbg_state
*state
,
148 const void *data
, size_t len
) {
150 DBGC ( state
, "HMAC_DRBG_%s %p update\n", hash
->name
, state
);
153 assert ( hash
!= NULL
);
154 assert ( state
!= NULL
);
155 assert ( ( data
!= NULL
) || ( len
== 0 ) );
157 /* 1. K = HMAC ( K, V || 0x00 || provided_data ) */
158 hmac_drbg_update_key ( hash
, state
, data
, len
, 0x00 );
160 /* 2. V = HMAC ( K, V ) */
161 hmac_drbg_update_value ( hash
, state
);
163 /* 3. If ( provided_data = Null ), then return K and V */
167 /* 4. K = HMAC ( K, V || 0x01 || provided_data ) */
168 hmac_drbg_update_key ( hash
, state
, data
, len
, 0x01 );
170 /* 5. V = HMAC ( K, V ) */
171 hmac_drbg_update_value ( hash
, state
);
173 /* 6. Return K and V */
177 * Instantiate HMAC_DRBG
179 * @v hash Underlying hash algorithm
180 * @v state HMAC_DRBG internal state to be initialised
181 * @v entropy Entropy input
182 * @v entropy_len Length of entropy input
183 * @v personal Personalisation string
184 * @v personal_len Length of personalisation string
186 * This is the HMAC_DRBG_Instantiate_algorithm function defined in ANS
187 * X9.82 Part 3-2007 Section 10.2.2.2.3 (NIST SP 800-90 Section
190 * The nonce must be included within the entropy input (i.e. the
191 * entropy input must contain at least 3/2 * security_strength bits of
192 * entropy, as per ANS X9.82 Part 3-2007 Section 8.4.2 (NIST SP 800-90
195 * The key, value and reseed counter are updated in-place within the
196 * HMAC_DRBG internal state.
198 void hmac_drbg_instantiate ( struct digest_algorithm
*hash
,
199 struct hmac_drbg_state
*state
,
200 const void *entropy
, size_t entropy_len
,
201 const void *personal
, size_t personal_len
){
202 size_t out_len
= hash
->digestsize
;
204 DBGC ( state
, "HMAC_DRBG_%s %p instantiate\n", hash
->name
, state
);
207 assert ( hash
!= NULL
);
208 assert ( state
!= NULL
);
209 assert ( entropy
!= NULL
);
210 assert ( ( personal
!= NULL
) || ( personal_len
== 0 ) );
212 /* 1. seed_material = entropy_input || nonce ||
213 * personalisation_string
216 /* 2. Key = 0x00 00..00 */
217 memset ( state
->key
, 0x00, out_len
);
219 /* 3. V = 0x01 01...01 */
220 memset ( state
->value
, 0x01, out_len
);
222 /* 4. ( Key, V ) = HMAC_DBRG_Update ( seed_material, Key, V )
223 * 5. reseed_counter = 1
224 * 6. Return V, Key and reseed_counter as the
225 * initial_working_state
227 hmac_drbg_reseed ( hash
, state
, entropy
, entropy_len
,
228 personal
, personal_len
);
234 * @v hash Underlying hash algorithm
235 * @v state HMAC_DRBG internal state
236 * @v entropy Entropy input
237 * @v entropy_len Length of entropy input
238 * @v additional Additional input
239 * @v additional_len Length of additional input
241 * This is the HMAC_DRBG_Reseed_algorithm function defined in ANS X9.82
242 * Part 3-2007 Section 10.2.2.2.4 (NIST SP 800-90 Section 10.1.2.4).
244 * The key, value and reseed counter are updated in-place within the
245 * HMAC_DRBG internal state.
247 void hmac_drbg_reseed ( struct digest_algorithm
*hash
,
248 struct hmac_drbg_state
*state
,
249 const void *entropy
, size_t entropy_len
,
250 const void *additional
, size_t additional_len
) {
251 uint8_t seed_material
[ entropy_len
+ additional_len
];
253 DBGC ( state
, "HMAC_DRBG_%s %p (re)seed\n", hash
->name
, state
);
256 assert ( hash
!= NULL
);
257 assert ( state
!= NULL
);
258 assert ( entropy
!= NULL
);
259 assert ( ( additional
!= NULL
) || ( additional_len
== 0 ) );
261 /* 1. seed_material = entropy_input || additional_input */
262 memcpy ( seed_material
, entropy
, entropy_len
);
263 memcpy ( ( seed_material
+ entropy_len
), additional
, additional_len
);
264 DBGC ( state
, "HMAC_DRBG_%s %p seed material :\n", hash
->name
, state
);
265 DBGC_HDA ( state
, 0, seed_material
, sizeof ( seed_material
) );
267 /* 2. ( Key, V ) = HMAC_DBRG_Update ( seed_material, Key, V ) */
268 hmac_drbg_update ( hash
, state
, seed_material
,
269 sizeof ( seed_material
) );
271 /* 3. reseed_counter = 1 */
272 state
->reseed_counter
= 1;
274 /* 4. Return V, Key and reseed_counter as the new_working_state */
278 * Generate pseudorandom bits using HMAC_DRBG
280 * @v hash Underlying hash algorithm
281 * @v state HMAC_DRBG internal state
282 * @v additional Additional input
283 * @v additional_len Length of additional input
284 * @v data Output buffer
285 * @v len Length of output buffer
286 * @ret rc Return status code
288 * This is the HMAC_DRBG_Generate_algorithm function defined in ANS X9.82
289 * Part 3-2007 Section 10.2.2.2.5 (NIST SP 800-90 Section 10.1.2.5).
291 * Requests must be for an integral number of bytes.
293 * The key, value and reseed counter are updated in-place within the
294 * HMAC_DRBG internal state.
296 * Note that the only permitted error is "reseed required".
298 int hmac_drbg_generate ( struct digest_algorithm
*hash
,
299 struct hmac_drbg_state
*state
,
300 const void *additional
, size_t additional_len
,
301 void *data
, size_t len
) {
302 size_t out_len
= hash
->digestsize
;
303 void *orig_data
= data
;
304 size_t orig_len
= len
;
307 DBGC ( state
, "HMAC_DRBG_%s %p generate\n", hash
->name
, state
);
310 assert ( hash
!= NULL
);
311 assert ( state
!= NULL
);
312 assert ( data
!= NULL
);
313 assert ( ( additional
!= NULL
) || ( additional_len
== 0 ) );
315 /* 1. If reseed_counter > reseed_interval, then return an
316 * indication that a reseed is required
318 if ( state
->reseed_counter
> HMAC_DRBG_RESEED_INTERVAL
) {
319 DBGC ( state
, "HMAC_DRBG_%s %p reseed interval exceeded\n",
324 /* 2. If additional_input != Null, then
325 * ( Key, V ) = HMAC_DRBG_Update ( additional_input, Key, V )
327 if ( additional_len
)
328 hmac_drbg_update ( hash
, state
, additional
, additional_len
);
331 * 4. While ( len ( temp ) < requested_number_of_bits ) do:
335 /* 4.1 V = HMAC ( Key, V ) */
336 hmac_drbg_update_value ( hash
, state
);
338 /* 4.2. temp = temp || V
339 * 5. returned_bits = Leftmost requested_number_of_bits
343 if ( frag_len
> out_len
)
345 memcpy ( data
, state
->value
, frag_len
);
350 /* 6. ( Key, V ) = HMAC_DRBG_Update ( additional_input, Key, V ) */
351 hmac_drbg_update ( hash
, state
, additional
, additional_len
);
353 /* 7. reseed_counter = reseed_counter + 1 */
354 state
->reseed_counter
++;
356 DBGC ( state
, "HMAC_DRBG_%s %p generated :\n", hash
->name
, state
);
357 DBGC_HDA ( state
, 0, orig_data
, orig_len
);
359 /* 8. Return SUCCESS, returned_bits, and the new values of
360 * Key, V and reseed_counter as the new_working_state