Add a return value to hasher_t.get_hash()
[strongswan.git] / src / libsimaka / simaka_crypto.c
1 /*
2 * Copyright (C) 2009-2011 Martin Willi
3 * Hochschule fuer Technik Rapperswil
4 *
5 * This program is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License as published by the
7 * Free Software Foundation; either version 2 of the License, or (at your
8 * option) any later version. See <http://www.fsf.org/copyleft/gpl.txt>.
9 *
10 * This program is distributed in the hope that it will be useful, but
11 * WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
12 * or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
13 * for more details.
14 */
15
16 #include "simaka_crypto.h"
17
18 #include "simaka_manager.h"
19
20 #include <debug.h>
21
22 /** length of the k_encr key */
23 #define KENCR_LEN 16
24 /** length of the k_auth key */
25 #define KAUTH_LEN 16
26 /** length of the MSK */
27 #define MSK_LEN 64
28 /** length of the EMSK */
29 #define EMSK_LEN 64
30
31 typedef struct private_simaka_crypto_t private_simaka_crypto_t;
32
33 /**
34 * Private data of an simaka_crypto_t object.
35 */
36 struct private_simaka_crypto_t {
37
38 /**
39 * Public simaka_crypto_t interface.
40 */
41 simaka_crypto_t public;
42
43 /**
44 * EAP type this crypto is used, SIM or AKA
45 */
46 eap_type_t type;
47
48 /**
49 * signer to create/verify AT_MAC
50 */
51 signer_t *signer;
52
53 /**
54 * crypter to encrypt/decrypt AT_ENCR_DATA
55 */
56 crypter_t *crypter;
57
58 /**
59 * hasher used in key derivation
60 */
61 hasher_t *hasher;
62
63 /**
64 * PRF function used in key derivation
65 */
66 prf_t *prf;
67
68 /**
69 * Random number generator to generate nonces
70 */
71 rng_t *rng;
72
73 /**
74 * Have k_encr/k_auth been derived?
75 */
76 bool derived;
77 };
78
79 METHOD(simaka_crypto_t, get_signer, signer_t*,
80 private_simaka_crypto_t *this)
81 {
82 return this->derived ? this->signer : NULL;
83 }
84
85 METHOD(simaka_crypto_t, get_crypter, crypter_t*,
86 private_simaka_crypto_t *this)
87 {
88 return this->derived ? this->crypter : NULL;
89 }
90
91 METHOD(simaka_crypto_t, get_rng, rng_t*,
92 private_simaka_crypto_t *this)
93 {
94 return this->rng;
95 }
96
97 /**
98 * Call SIM/AKA key hook
99 */
100 static void call_hook(private_simaka_crypto_t *this, chunk_t encr, chunk_t auth)
101 {
102 simaka_manager_t *mgr;
103
104 switch (this->type)
105 {
106 case EAP_SIM:
107 mgr = lib->get(lib, "sim-manager");
108 break;
109 case EAP_AKA:
110 mgr = lib->get(lib, "aka-manager");
111 break;
112 default:
113 return;
114 }
115 mgr->key_hook(mgr, encr, auth);
116 }
117
118 METHOD(simaka_crypto_t, derive_keys_full, bool,
119 private_simaka_crypto_t *this, identification_t *id,
120 chunk_t data, chunk_t *mk, chunk_t *msk)
121 {
122 chunk_t str, k_encr, k_auth;
123 int i;
124
125 /* For SIM: MK = SHA1(Identity|n*Kc|NONCE_MT|Version List|Selected Version)
126 * For AKA: MK = SHA1(Identity|IK|CK) */
127 if (!this->hasher->get_hash(this->hasher, id->get_encoding(id), NULL))
128 {
129 return FALSE;
130 }
131 this->hasher->allocate_hash(this->hasher, data, mk);
132 DBG3(DBG_LIB, "MK %B", mk);
133
134 /* K_encr | K_auth | MSK | EMSK = prf() | prf() | prf() | prf() */
135 if (this->prf->set_key(this->prf, *mk))
136 {
137 return FALSE;
138 }
139 str = chunk_alloca(this->prf->get_block_size(this->prf) * 3);
140 for (i = 0; i < 3; i++)
141 {
142 if (!this->prf->get_bytes(this->prf, chunk_empty,
143 str.ptr + str.len / 3 * i))
144 {
145 chunk_clear(mk);
146 return FALSE;
147 }
148 }
149
150 k_encr = chunk_create(str.ptr, KENCR_LEN);
151 k_auth = chunk_create(str.ptr + KENCR_LEN, KAUTH_LEN);
152 DBG3(DBG_LIB, "K_encr %B\nK_auth %B\nMSK %B", &k_encr, &k_auth, &msk);
153
154 if (!this->signer->set_key(this->signer, k_auth) ||
155 !this->crypter->set_key(this->crypter, k_encr))
156 {
157 chunk_clear(mk);
158 return FALSE;
159 }
160
161 *msk = chunk_create(str.ptr + KENCR_LEN + KAUTH_LEN, MSK_LEN);
162
163 call_hook(this, k_encr, k_auth);
164
165 this->derived = TRUE;
166 return TRUE;
167 }
168
169 METHOD(simaka_crypto_t, derive_keys_reauth, bool,
170 private_simaka_crypto_t *this, chunk_t mk)
171 {
172 chunk_t str, k_encr, k_auth;
173 int i;
174
175 /* K_encr | K_auth = prf() | prf() */
176 if (!this->prf->set_key(this->prf, mk))
177 {
178 return FALSE;
179 }
180 str = chunk_alloca(this->prf->get_block_size(this->prf) * 2);
181 for (i = 0; i < 2; i++)
182 {
183 if (!this->prf->get_bytes(this->prf, chunk_empty,
184 str.ptr + str.len / 2 * i))
185 {
186 return FALSE;
187 }
188 }
189 k_encr = chunk_create(str.ptr, KENCR_LEN);
190 k_auth = chunk_create(str.ptr + KENCR_LEN, KAUTH_LEN);
191 DBG3(DBG_LIB, "K_encr %B\nK_auth %B", &k_encr, &k_auth);
192
193 if (!this->signer->set_key(this->signer, k_auth) ||
194 !this->crypter->set_key(this->crypter, k_encr))
195 {
196 return FALSE;
197 }
198
199 call_hook(this, k_encr, k_auth);
200
201 this->derived = TRUE;
202 return TRUE;
203 }
204
205 METHOD(simaka_crypto_t, derive_keys_reauth_msk, bool,
206 private_simaka_crypto_t *this, identification_t *id, chunk_t counter,
207 chunk_t nonce_s, chunk_t mk, chunk_t *msk)
208 {
209 char xkey[HASH_SIZE_SHA1];
210 chunk_t str;
211 int i;
212
213 if (!this->hasher->get_hash(this->hasher, id->get_encoding(id), NULL) ||
214 !this->hasher->get_hash(this->hasher, counter, NULL) ||
215 !this->hasher->get_hash(this->hasher, nonce_s, NULL) ||
216 !this->hasher->get_hash(this->hasher, mk, xkey))
217 {
218 return FALSE;
219 }
220
221 /* MSK | EMSK = prf() | prf() | prf() | prf() */
222 if (!this->prf->set_key(this->prf, chunk_create(xkey, sizeof(xkey))))
223 {
224 return FALSE;
225 }
226 str = chunk_alloca(this->prf->get_block_size(this->prf) * 2);
227 for (i = 0; i < 2; i++)
228 {
229 if (!this->prf->get_bytes(this->prf, chunk_empty,
230 str.ptr + str.len / 2 * i))
231 {
232 return FALSE;
233 }
234 }
235 *msk = chunk_create(str.ptr, MSK_LEN);
236 DBG3(DBG_LIB, "MSK %B", msk);
237
238 return TRUE;
239 }
240
241 METHOD(simaka_crypto_t, clear_keys, void,
242 private_simaka_crypto_t *this)
243 {
244 this->derived = FALSE;
245 }
246
247 METHOD(simaka_crypto_t, destroy, void,
248 private_simaka_crypto_t *this)
249 {
250 DESTROY_IF(this->rng);
251 DESTROY_IF(this->hasher);
252 DESTROY_IF(this->prf);
253 DESTROY_IF(this->signer);
254 DESTROY_IF(this->crypter);
255 free(this);
256 }
257
258 /**
259 * See header
260 */
261 simaka_crypto_t *simaka_crypto_create(eap_type_t type)
262 {
263 private_simaka_crypto_t *this;
264
265 INIT(this,
266 .public = {
267 .get_signer = _get_signer,
268 .get_crypter = _get_crypter,
269 .get_rng = _get_rng,
270 .derive_keys_full = _derive_keys_full,
271 .derive_keys_reauth = _derive_keys_reauth,
272 .derive_keys_reauth_msk = _derive_keys_reauth_msk,
273 .clear_keys = _clear_keys,
274 .destroy = _destroy,
275 },
276 .type = type,
277 .rng = lib->crypto->create_rng(lib->crypto, RNG_WEAK),
278 .hasher = lib->crypto->create_hasher(lib->crypto, HASH_SHA1),
279 .prf = lib->crypto->create_prf(lib->crypto, PRF_FIPS_SHA1_160),
280 .signer = lib->crypto->create_signer(lib->crypto, AUTH_HMAC_SHA1_128),
281 .crypter = lib->crypto->create_crypter(lib->crypto, ENCR_AES_CBC, 16),
282 );
283 if (!this->rng || !this->hasher || !this->prf ||
284 !this->signer || !this->crypter)
285 {
286 DBG1(DBG_LIB, "unable to use %N, missing algorithms",
287 eap_type_names, type);
288 destroy(this);
289 return NULL;
290 }
291 return &this->public;
292 }