Migratd simaka_crypto to INIT/METHOD macros
[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, chunk_t,
119 private_simaka_crypto_t *this, identification_t *id,
120 chunk_t data, chunk_t *mk)
121 {
122 chunk_t str, msk, 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 this->hasher->get_hash(this->hasher, id->get_encoding(id), NULL);
128 this->hasher->allocate_hash(this->hasher, data, mk);
129 DBG3(DBG_LIB, "MK %B", mk);
130
131 /* K_encr | K_auth | MSK | EMSK = prf() | prf() | prf() | prf() */
132 this->prf->set_key(this->prf, *mk);
133 str = chunk_alloca(this->prf->get_block_size(this->prf) * 3);
134 for (i = 0; i < 3; i++)
135 {
136 this->prf->get_bytes(this->prf, chunk_empty, str.ptr + str.len / 3 * i);
137 }
138
139 k_encr = chunk_create(str.ptr, KENCR_LEN);
140 k_auth = chunk_create(str.ptr + KENCR_LEN, KAUTH_LEN);
141 msk = chunk_create(str.ptr + KENCR_LEN + KAUTH_LEN, MSK_LEN);
142 DBG3(DBG_LIB, "K_encr %B\nK_auth %B\nMSK %B", &k_encr, &k_auth, &msk);
143
144 this->signer->set_key(this->signer, k_auth);
145 this->crypter->set_key(this->crypter, k_encr);
146
147 call_hook(this, k_encr, k_auth);
148
149 this->derived = TRUE;
150 return chunk_clone(msk);
151 }
152
153 METHOD(simaka_crypto_t, derive_keys_reauth, void,
154 private_simaka_crypto_t *this, chunk_t mk)
155 {
156 chunk_t str, k_encr, k_auth;
157 int i;
158
159 /* K_encr | K_auth = prf() | prf() */
160 this->prf->set_key(this->prf, mk);
161 str = chunk_alloca(this->prf->get_block_size(this->prf) * 2);
162 for (i = 0; i < 2; i++)
163 {
164 this->prf->get_bytes(this->prf, chunk_empty, str.ptr + str.len / 2 * i);
165 }
166 k_encr = chunk_create(str.ptr, KENCR_LEN);
167 k_auth = chunk_create(str.ptr + KENCR_LEN, KAUTH_LEN);
168 DBG3(DBG_LIB, "K_encr %B\nK_auth %B", &k_encr, &k_auth);
169
170 this->signer->set_key(this->signer, k_auth);
171 this->crypter->set_key(this->crypter, k_encr);
172
173 call_hook(this, k_encr, k_auth);
174
175 this->derived = TRUE;
176 }
177
178 METHOD(simaka_crypto_t, derive_keys_reauth_msk, chunk_t,
179 private_simaka_crypto_t *this, identification_t *id, chunk_t counter,
180 chunk_t nonce_s, chunk_t mk)
181 {
182 char xkey[HASH_SIZE_SHA1];
183 chunk_t str, msk;
184 int i;
185
186 this->hasher->get_hash(this->hasher, id->get_encoding(id), NULL);
187 this->hasher->get_hash(this->hasher, counter, NULL);
188 this->hasher->get_hash(this->hasher, nonce_s, NULL);
189 this->hasher->get_hash(this->hasher, mk, xkey);
190
191 /* MSK | EMSK = prf() | prf() | prf() | prf() */
192 this->prf->set_key(this->prf, chunk_create(xkey, sizeof(xkey)));
193 str = chunk_alloca(this->prf->get_block_size(this->prf) * 2);
194 for (i = 0; i < 2; i++)
195 {
196 this->prf->get_bytes(this->prf, chunk_empty, str.ptr + str.len / 2 * i);
197 }
198 msk = chunk_create(str.ptr, MSK_LEN);
199 DBG3(DBG_LIB, "MSK %B", &msk);
200
201 return chunk_clone(msk);
202 }
203
204 METHOD(simaka_crypto_t, clear_keys, void,
205 private_simaka_crypto_t *this)
206 {
207 this->derived = FALSE;
208 }
209
210 METHOD(simaka_crypto_t, destroy, void,
211 private_simaka_crypto_t *this)
212 {
213 DESTROY_IF(this->rng);
214 DESTROY_IF(this->hasher);
215 DESTROY_IF(this->prf);
216 DESTROY_IF(this->signer);
217 DESTROY_IF(this->crypter);
218 free(this);
219 }
220
221 /**
222 * See header
223 */
224 simaka_crypto_t *simaka_crypto_create(eap_type_t type)
225 {
226 private_simaka_crypto_t *this;
227
228 INIT(this,
229 .public = {
230 .get_signer = _get_signer,
231 .get_crypter = _get_crypter,
232 .get_rng = _get_rng,
233 .derive_keys_full = _derive_keys_full,
234 .derive_keys_reauth = _derive_keys_reauth,
235 .derive_keys_reauth_msk = _derive_keys_reauth_msk,
236 .clear_keys = _clear_keys,
237 .destroy = _destroy,
238 },
239 .type = type,
240 .rng = lib->crypto->create_rng(lib->crypto, RNG_WEAK),
241 .hasher = lib->crypto->create_hasher(lib->crypto, HASH_SHA1),
242 .prf = lib->crypto->create_prf(lib->crypto, PRF_FIPS_SHA1_160),
243 .signer = lib->crypto->create_signer(lib->crypto, AUTH_HMAC_SHA1_128),
244 .crypter = lib->crypto->create_crypter(lib->crypto, ENCR_AES_CBC, 16),
245 );
246 if (!this->rng || !this->hasher || !this->prf ||
247 !this->signer || !this->crypter)
248 {
249 DBG1(DBG_LIB, "unable to use %N, missing algorithms",
250 eap_type_names, type);
251 destroy(this);
252 return NULL;
253 }
254 return &this->public;
255 }