aboutsummaryrefslogtreecommitdiffstats
path: root/src/crypto/milenage.c
blob: cf0c60e5510fae960d2966f536dd7b84f64f7a06 (plain)
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
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
/*
 * 3GPP AKA - Milenage algorithm (3GPP TS 35.205, .206, .207, .208)
 * Copyright (c) 2006-2007 <j@w1.fi>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 *
 * Alternatively, this software may be distributed under the terms of BSD
 * license.
 *
 * See README and COPYING for more details.
 *
 * This file implements an example authentication algorithm defined for 3GPP
 * AKA. This can be used to implement a simple HLR/AuC into hlr_auc_gw to allow
 * EAP-AKA to be tested properly with real USIM cards.
 *
 * This implementations assumes that the r1..r5 and c1..c5 constants defined in
 * TS 35.206 are used, i.e., r1=64, r2=0, r3=32, r4=64, r5=96, c1=00..00,
 * c2=00..01, c3=00..02, c4=00..04, c5=00..08. The block cipher is assumed to
 * be AES (Rijndael).
 */

#include "includes.h"

#include "common.h"
#include "crypto/aes_wrap.h"
#include "milenage.h"


/**
 * milenage_f1 - Milenage f1 and f1* algorithms
 * @opc: OPc = 128-bit value derived from OP and K
 * @k: K = 128-bit subscriber key
 * @_rand: RAND = 128-bit random challenge
 * @sqn: SQN = 48-bit sequence number
 * @amf: AMF = 16-bit authentication management field
 * @mac_a: Buffer for MAC-A = 64-bit network authentication code, or %NULL
 * @mac_s: Buffer for MAC-S = 64-bit resync authentication code, or %NULL
 * Returns: 0 on success, -1 on failure
 */
int milenage_f1(const u8 *opc, const u8 *k, const u8 *_rand,
		const u8 *sqn, const u8 *amf, u8 *mac_a, u8 *mac_s)
{
	u8 tmp1[16], tmp2[16], tmp3[16];
	int i;

	/* tmp1 = TEMP = E_K(RAND XOR OP_C) */
	for (i = 0; i < 16; i++)
		tmp1[i] = _rand[i] ^ opc[i];
	if (aes_128_encrypt_block(k, tmp1, tmp1))
		return -1;

	/* tmp2 = IN1 = SQN || AMF || SQN || AMF */
	os_memcpy(tmp2, sqn, 6);
	os_memcpy(tmp2 + 6, amf, 2);
	os_memcpy(tmp2 + 8, tmp2, 8);

	/* OUT1 = E_K(TEMP XOR rot(IN1 XOR OP_C, r1) XOR c1) XOR OP_C */

	/* rotate (tmp2 XOR OP_C) by r1 (= 0x40 = 8 bytes) */
	for (i = 0; i < 16; i++)
		tmp3[(i + 8) % 16] = tmp2[i] ^ opc[i];
	/* XOR with TEMP = E_K(RAND XOR OP_C) */
	for (i = 0; i < 16; i++)
		tmp3[i] ^= tmp1[i];
	/* XOR with c1 (= ..00, i.e., NOP) */

	/* f1 || f1* = E_K(tmp3) XOR OP_c */
	if (aes_128_encrypt_block(k, tmp3, tmp1))
		return -1;
	for (i = 0; i < 16; i++)
		tmp1[i] ^= opc[i];
	if (mac_a)
		os_memcpy(mac_a, tmp1, 8); /* f1 */
	if (mac_s)
		os_memcpy(mac_s, tmp1 + 8, 8); /* f1* */
	return 0;
}


/**
 * milenage_f2345 - Milenage f2, f3, f4, f5, f5* algorithms
 * @opc: OPc = 128-bit value derived from OP and K
 * @k: K = 128-bit subscriber key
 * @_rand: RAND = 128-bit random challenge
 * @res: Buffer for RES = 64-bit signed response (f2), or %NULL
 * @ck: Buffer for CK = 128-bit confidentiality key (f3), or %NULL
 * @ik: Buffer for IK = 128-bit integrity key (f4), or %NULL
 * @ak: Buffer for AK = 48-bit anonymity key (f5), or %NULL
 * @akstar: Buffer for AK = 48-bit anonymity key (f5*), or %NULL
 * Returns: 0 on success, -1 on failure
 */
int milenage_f2345(const u8 *opc, const u8 *k, const u8 *_rand,
		   u8 *res, u8 *ck, u8 *ik, u8 *ak, u8 *akstar)
{
	u8 tmp1[16], tmp2[16], tmp3[16];
	int i;

	/* tmp2 = TEMP = E_K(RAND XOR OP_C) */
	for (i = 0; i < 16; i++)
		tmp1[i] = _rand[i] ^ opc[i];
	if (aes_128_encrypt_block(k, tmp1, tmp2))
		return -1;

	/* OUT2 = E_K(rot(TEMP XOR OP_C, r2) XOR c2) XOR OP_C */
	/* OUT3 = E_K(rot(TEMP XOR OP_C, r3) XOR c3) XOR OP_C */
	/* OUT4 = E_K(rot(TEMP XOR OP_C, r4) XOR c4) XOR OP_C */
	/* OUT5 = E_K(rot(TEMP XOR OP_C, r5) XOR c5) XOR OP_C */

	/* f2 and f5 */
	/* rotate by r2 (= 0, i.e., NOP) */
	for (i = 0; i < 16; i++)
		tmp1[i] = tmp2[i] ^ opc[i];
	tmp1[15] ^= 1; /* XOR c2 (= ..01) */
	/* f5 || f2 = E_K(tmp1) XOR OP_c */
	if (aes_128_encrypt_block(k, tmp1, tmp3))
		return -1;
	for (i = 0; i < 16; i++)
		tmp3[i] ^= opc[i];
	if (res)
		os_memcpy(res, tmp3 + 8, 8); /* f2 */
	if (ak)
		os_memcpy(ak, tmp3, 6); /* f5 */

	/* f3 */
	if (ck) {
		/* rotate by r3 = 0x20 = 4 bytes */
		for (i = 0; i < 16; i++)
			tmp1[(i + 12) % 16] = tmp2[i] ^ opc[i];
		tmp1[15] ^= 2; /* XOR c3 (= ..02) */
		if (aes_128_encrypt_block(k, tmp1, ck))
			return -1;
		for (i = 0; i < 16; i++)
			ck[i] ^= opc[i];
	}

	/* f4 */
	if (ik) {
		/* rotate by r4 = 0x40 = 8 bytes */
		for (i = 0; i < 16; i++)
			tmp1[(i + 8) % 16] = tmp2[i] ^ opc[i];
		tmp1[15] ^= 4; /* XOR c4 (= ..04) */
		if (aes_128_encrypt_block(k, tmp1, ik))
			return -1;
		for (i = 0; i < 16; i++)
			ik[i] ^= opc[i];
	}

	/* f5* */
	if (akstar) {
		/* rotate by r5 = 0x60 = 12 bytes */
		for (i = 0; i < 16; i++)
			tmp1[(i + 4) % 16] = tmp2[i] ^ opc[i];
		tmp1[15] ^= 8; /* XOR c5 (= ..08) */
		if (aes_128_encrypt_block(k, tmp1, tmp1))
			return -1;
		for (i = 0; i < 6; i++)
			akstar[i] = tmp1[i] ^ opc[i];
	}

	return 0;
}


/**
 * milenage_generate - Generate AKA AUTN,IK,CK,RES
 * @opc: OPc = 128-bit operator variant algorithm configuration field (encr.)
 * @amf: AMF = 16-bit authentication management field
 * @k: K = 128-bit subscriber key
 * @sqn: SQN = 48-bit sequence number
 * @_rand: RAND = 128-bit random challenge
 * @autn: Buffer for AUTN = 128-bit authentication token
 * @ik: Buffer for IK = 128-bit integrity key (f4), or %NULL
 * @ck: Buffer for CK = 128-bit confidentiality key (f3), or %NULL
 * @res: Buffer for RES = 64-bit signed response (f2), or %NULL
 * @res_len: Max length for res; set to used length or 0 on failure
 */
void milenage_generate(const u8 *opc, const u8 *amf, const u8 *k,
		       const u8 *sqn, const u8 *_rand, u8 *autn, u8 *ik,
		       u8 *ck, u8 *res, size_t *res_len)
{
	int i;
	u8 mac_a[8], ak[6];

	if (*res_len < 8) {
		*res_len = 0;
		return;
	}
	if (milenage_f1(opc, k, _rand, sqn, amf, mac_a, NULL) ||
	    milenage_f2345(opc, k, _rand, res, ck, ik, ak, NULL)) {
		*res_len = 0;
		return;
	}
	*res_len = 8;

	/* AUTN = (SQN ^ AK) || AMF || MAC */
	for (i = 0; i < 6; i++)
		autn[i] = sqn[i] ^ ak[i];
	os_memcpy(autn + 6, amf, 2);
	os_memcpy(autn + 8, mac_a, 8);
}


/**
 * milenage_auts - Milenage AUTS validation
 * @opc: OPc = 128-bit operator variant algorithm configuration field (encr.)
 * @k: K = 128-bit subscriber key
 * @_rand: RAND = 128-bit random challenge
 * @auts: AUTS = 112-bit authentication token from client
 * @sqn: Buffer for SQN = 48-bit sequence number
 * Returns: 0 = success (sqn filled), -1 on failure
 */
int milenage_auts(const u8 *opc, const u8 *k, const u8 *_rand, const u8 *auts,
		  u8 *sqn)
{
	u8 amf[2] = { 0x00, 0x00 }; /* TS 33.102 v7.0.0, 6.3.3 */
	u8 ak[6], mac_s[8];
	int i;

	if (milenage_f2345(opc, k, _rand, NULL, NULL, NULL, NULL, ak))
		return -1;
	for (i = 0; i < 6; i++)
		sqn[i] = auts[i] ^ ak[i];
	if (milenage_f1(opc, k, _rand, sqn, amf, NULL, mac_s) ||
	    memcmp(mac_s, auts + 6, 8) != 0)
		return -1;
	return 0;
}


/**
 * gsm_milenage - Generate GSM-Milenage (3GPP TS 55.205) authentication triplet
 * @opc: OPc = 128-bit operator variant algorithm configuration field (encr.)
 * @k: K = 128-bit subscriber key
 * @_rand: RAND = 128-bit random challenge
 * @sres: Buffer for SRES = 32-bit SRES
 * @kc: Buffer for Kc = 64-bit Kc
 * Returns: 0 on success, -1 on failure
 */
int gsm_milenage(const u8 *opc, const u8 *k, const u8 *_rand, u8 *sres, u8 *kc)
{
	u8 res[8], ck[16], ik[16];
	int i;

	if (milenage_f2345(opc, k, _rand, res, ck, ik, NULL, NULL))
		return -1;

	for (i = 0; i < 8; i++)
		kc[i] = ck[i] ^ ck[i + 8] ^ ik[i] ^ ik[i + 8];

#ifdef GSM_MILENAGE_ALT_SRES
	os_memcpy(sres, res, 4);
#else /* GSM_MILENAGE_ALT_SRES */
	for (i = 0; i < 4; i++)
		sres[i] = res[i] ^ res[i + 4];
#endif /* GSM_MILENAGE_ALT_SRES */
	return 0;
}


/**
 * milenage_generate - Generate AKA AUTN,IK,CK,RES
 * @opc: OPc = 128-bit operator variant algorithm configuration field (encr.)
 * @k: K = 128-bit subscriber key
 * @sqn: SQN = 48-bit sequence number
 * @_rand: RAND = 128-bit random challenge
 * @autn: AUTN = 128-bit authentication token
 * @ik: Buffer for IK = 128-bit integrity key (f4), or %NULL
 * @ck: Buffer for CK = 128-bit confidentiality key (f3), or %NULL
 * @res: Buffer for RES = 64-bit signed response (f2), or %NULL
 * @res_len: Variable that will be set to RES length
 * @auts: 112-bit buffer for AUTS
 * Returns: 0 on success, -1 on failure, or -2 on synchronization failure
 */
int milenage_check(const u8 *opc, const u8 *k, const u8 *sqn, const u8 *_rand,
		   const u8 *autn, u8 *ik, u8 *ck, u8 *res, size_t *res_len,
		   u8 *auts)
{
	int i;
	u8 mac_a[8], ak[6], rx_sqn[6];
	const u8 *amf;

	wpa_hexdump(MSG_DEBUG, "Milenage: AUTN", autn, 16);
	wpa_hexdump(MSG_DEBUG, "Milenage: RAND", _rand, 16);

	if (milenage_f2345(opc, k, _rand, res, ck, ik, ak, NULL))
		return -1;

	*res_len = 8;
	wpa_hexdump_key(MSG_DEBUG, "Milenage: RES", res, *res_len);
	wpa_hexdump_key(MSG_DEBUG, "Milenage: CK", ck, 16);
	wpa_hexdump_key(MSG_DEBUG, "Milenage: IK", ik, 16);
	wpa_hexdump_key(MSG_DEBUG, "Milenage: AK", ak, 6);

	/* AUTN = (SQN ^ AK) || AMF || MAC */
	for (i = 0; i < 6; i++)
		rx_sqn[i] = autn[i] ^ ak[i];
	wpa_hexdump(MSG_DEBUG, "Milenage: SQN", rx_sqn, 6);

	if (os_memcmp(rx_sqn, sqn, 6) <= 0) {
		u8 auts_amf[2] = { 0x00, 0x00 }; /* TS 33.102 v7.0.0, 6.3.3 */
		if (milenage_f2345(opc, k, _rand, NULL, NULL, NULL, NULL, ak))
			return -1;
		wpa_hexdump_key(MSG_DEBUG, "Milenage: AK*", ak, 6);
		for (i = 0; i < 6; i++)
			auts[i] = sqn[i] ^ ak[i];
		if (milenage_f1(opc, k, _rand, sqn, auts_amf, NULL, auts + 6))
			return -1;
		wpa_hexdump(MSG_DEBUG, "Milenage: AUTS", auts, 14);
		return -2;
	}

	amf = autn + 6;
	wpa_hexdump(MSG_DEBUG, "Milenage: AMF", amf, 2);
	if (milenage_f1(opc, k, _rand, rx_sqn, amf, mac_a, NULL))
		return -1;

	wpa_hexdump(MSG_DEBUG, "Milenage: MAC_A", mac_a, 8);

	if (os_memcmp(mac_a, autn + 8, 8) != 0) {
		wpa_printf(MSG_DEBUG, "Milenage: MAC mismatch");
		wpa_hexdump(MSG_DEBUG, "Milenage: Received MAC_A",
			    autn + 8, 8);
		return -1;
	}

	return 0;
}