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