Line data Source code
1 : /*
2 : * 3GPP AKA - Milenage algorithm (3GPP TS 35.205, .206, .207, .208)
3 : * Copyright (c) 2006-2007 <j@w1.fi>
4 : *
5 : * This software may be distributed under the terms of the BSD license.
6 : * See README for more details.
7 : *
8 : * This file implements an example authentication algorithm defined for 3GPP
9 : * AKA. This can be used to implement a simple HLR/AuC into hlr_auc_gw to allow
10 : * EAP-AKA to be tested properly with real USIM cards.
11 : *
12 : * This implementations assumes that the r1..r5 and c1..c5 constants defined in
13 : * TS 35.206 are used, i.e., r1=64, r2=0, r3=32, r4=64, r5=96, c1=00..00,
14 : * c2=00..01, c3=00..02, c4=00..04, c5=00..08. The block cipher is assumed to
15 : * be AES (Rijndael).
16 : */
17 :
18 : #include "includes.h"
19 :
20 : #include "common.h"
21 : #include "crypto/aes_wrap.h"
22 : #include "milenage.h"
23 :
24 :
25 : /**
26 : * milenage_f1 - Milenage f1 and f1* algorithms
27 : * @opc: OPc = 128-bit value derived from OP and K
28 : * @k: K = 128-bit subscriber key
29 : * @_rand: RAND = 128-bit random challenge
30 : * @sqn: SQN = 48-bit sequence number
31 : * @amf: AMF = 16-bit authentication management field
32 : * @mac_a: Buffer for MAC-A = 64-bit network authentication code, or %NULL
33 : * @mac_s: Buffer for MAC-S = 64-bit resync authentication code, or %NULL
34 : * Returns: 0 on success, -1 on failure
35 : */
36 92 : int milenage_f1(const u8 *opc, const u8 *k, const u8 *_rand,
37 : const u8 *sqn, const u8 *amf, u8 *mac_a, u8 *mac_s)
38 : {
39 : u8 tmp1[16], tmp2[16], tmp3[16];
40 : int i;
41 :
42 : /* tmp1 = TEMP = E_K(RAND XOR OP_C) */
43 1564 : for (i = 0; i < 16; i++)
44 1472 : tmp1[i] = _rand[i] ^ opc[i];
45 92 : if (aes_128_encrypt_block(k, tmp1, tmp1))
46 0 : return -1;
47 :
48 : /* tmp2 = IN1 = SQN || AMF || SQN || AMF */
49 92 : os_memcpy(tmp2, sqn, 6);
50 92 : os_memcpy(tmp2 + 6, amf, 2);
51 92 : os_memcpy(tmp2 + 8, tmp2, 8);
52 :
53 : /* OUT1 = E_K(TEMP XOR rot(IN1 XOR OP_C, r1) XOR c1) XOR OP_C */
54 :
55 : /* rotate (tmp2 XOR OP_C) by r1 (= 0x40 = 8 bytes) */
56 1564 : for (i = 0; i < 16; i++)
57 1472 : tmp3[(i + 8) % 16] = tmp2[i] ^ opc[i];
58 : /* XOR with TEMP = E_K(RAND XOR OP_C) */
59 1564 : for (i = 0; i < 16; i++)
60 1472 : tmp3[i] ^= tmp1[i];
61 : /* XOR with c1 (= ..00, i.e., NOP) */
62 :
63 : /* f1 || f1* = E_K(tmp3) XOR OP_c */
64 92 : if (aes_128_encrypt_block(k, tmp3, tmp1))
65 0 : return -1;
66 1564 : for (i = 0; i < 16; i++)
67 1472 : tmp1[i] ^= opc[i];
68 92 : if (mac_a)
69 83 : os_memcpy(mac_a, tmp1, 8); /* f1 */
70 92 : if (mac_s)
71 9 : os_memcpy(mac_s, tmp1 + 8, 8); /* f1* */
72 92 : return 0;
73 : }
74 :
75 :
76 : /**
77 : * milenage_f2345 - Milenage f2, f3, f4, f5, f5* algorithms
78 : * @opc: OPc = 128-bit value derived from OP and K
79 : * @k: K = 128-bit subscriber key
80 : * @_rand: RAND = 128-bit random challenge
81 : * @res: Buffer for RES = 64-bit signed response (f2), or %NULL
82 : * @ck: Buffer for CK = 128-bit confidentiality key (f3), or %NULL
83 : * @ik: Buffer for IK = 128-bit integrity key (f4), or %NULL
84 : * @ak: Buffer for AK = 48-bit anonymity key (f5), or %NULL
85 : * @akstar: Buffer for AK = 48-bit anonymity key (f5*), or %NULL
86 : * Returns: 0 on success, -1 on failure
87 : */
88 303 : int milenage_f2345(const u8 *opc, const u8 *k, const u8 *_rand,
89 : u8 *res, u8 *ck, u8 *ik, u8 *ak, u8 *akstar)
90 : {
91 : u8 tmp1[16], tmp2[16], tmp3[16];
92 : int i;
93 :
94 : /* tmp2 = TEMP = E_K(RAND XOR OP_C) */
95 5151 : for (i = 0; i < 16; i++)
96 4848 : tmp1[i] = _rand[i] ^ opc[i];
97 303 : if (aes_128_encrypt_block(k, tmp1, tmp2))
98 3 : return -1;
99 :
100 : /* OUT2 = E_K(rot(TEMP XOR OP_C, r2) XOR c2) XOR OP_C */
101 : /* OUT3 = E_K(rot(TEMP XOR OP_C, r3) XOR c3) XOR OP_C */
102 : /* OUT4 = E_K(rot(TEMP XOR OP_C, r4) XOR c4) XOR OP_C */
103 : /* OUT5 = E_K(rot(TEMP XOR OP_C, r5) XOR c5) XOR OP_C */
104 :
105 : /* f2 and f5 */
106 : /* rotate by r2 (= 0, i.e., NOP) */
107 5100 : for (i = 0; i < 16; i++)
108 4800 : tmp1[i] = tmp2[i] ^ opc[i];
109 300 : tmp1[15] ^= 1; /* XOR c2 (= ..01) */
110 : /* f5 || f2 = E_K(tmp1) XOR OP_c */
111 300 : if (aes_128_encrypt_block(k, tmp1, tmp3))
112 3 : return -1;
113 5049 : for (i = 0; i < 16; i++)
114 4752 : tmp3[i] ^= opc[i];
115 297 : if (res)
116 288 : os_memcpy(res, tmp3 + 8, 8); /* f2 */
117 297 : if (ak)
118 87 : os_memcpy(ak, tmp3, 6); /* f5 */
119 :
120 : /* f3 */
121 297 : if (ck) {
122 : /* rotate by r3 = 0x20 = 4 bytes */
123 4896 : for (i = 0; i < 16; i++)
124 4608 : tmp1[(i + 12) % 16] = tmp2[i] ^ opc[i];
125 288 : tmp1[15] ^= 2; /* XOR c3 (= ..02) */
126 288 : if (aes_128_encrypt_block(k, tmp1, ck))
127 3 : return -1;
128 4845 : for (i = 0; i < 16; i++)
129 4560 : ck[i] ^= opc[i];
130 : }
131 :
132 : /* f4 */
133 294 : if (ik) {
134 : /* rotate by r4 = 0x40 = 8 bytes */
135 4845 : for (i = 0; i < 16; i++)
136 4560 : tmp1[(i + 8) % 16] = tmp2[i] ^ opc[i];
137 285 : tmp1[15] ^= 4; /* XOR c4 (= ..04) */
138 285 : if (aes_128_encrypt_block(k, tmp1, ik))
139 3 : return -1;
140 4794 : for (i = 0; i < 16; i++)
141 4512 : ik[i] ^= opc[i];
142 : }
143 :
144 : /* f5* */
145 291 : if (akstar) {
146 : /* rotate by r5 = 0x60 = 12 bytes */
147 153 : for (i = 0; i < 16; i++)
148 144 : tmp1[(i + 4) % 16] = tmp2[i] ^ opc[i];
149 9 : tmp1[15] ^= 8; /* XOR c5 (= ..08) */
150 9 : if (aes_128_encrypt_block(k, tmp1, tmp1))
151 0 : return -1;
152 63 : for (i = 0; i < 6; i++)
153 54 : akstar[i] = tmp1[i] ^ opc[i];
154 : }
155 :
156 291 : return 0;
157 : }
158 :
159 :
160 : /**
161 : * milenage_generate - Generate AKA AUTN,IK,CK,RES
162 : * @opc: OPc = 128-bit operator variant algorithm configuration field (encr.)
163 : * @amf: AMF = 16-bit authentication management field
164 : * @k: K = 128-bit subscriber key
165 : * @sqn: SQN = 48-bit sequence number
166 : * @_rand: RAND = 128-bit random challenge
167 : * @autn: Buffer for AUTN = 128-bit authentication token
168 : * @ik: Buffer for IK = 128-bit integrity key (f4), or %NULL
169 : * @ck: Buffer for CK = 128-bit confidentiality key (f3), or %NULL
170 : * @res: Buffer for RES = 64-bit signed response (f2), or %NULL
171 : * @res_len: Max length for res; set to used length or 0 on failure
172 : */
173 50 : void milenage_generate(const u8 *opc, const u8 *amf, const u8 *k,
174 : const u8 *sqn, const u8 *_rand, u8 *autn, u8 *ik,
175 : u8 *ck, u8 *res, size_t *res_len)
176 : {
177 : int i;
178 : u8 mac_a[8], ak[6];
179 :
180 50 : if (*res_len < 8) {
181 0 : *res_len = 0;
182 0 : return;
183 : }
184 100 : if (milenage_f1(opc, k, _rand, sqn, amf, mac_a, NULL) ||
185 50 : milenage_f2345(opc, k, _rand, res, ck, ik, ak, NULL)) {
186 0 : *res_len = 0;
187 0 : return;
188 : }
189 50 : *res_len = 8;
190 :
191 : /* AUTN = (SQN ^ AK) || AMF || MAC */
192 350 : for (i = 0; i < 6; i++)
193 300 : autn[i] = sqn[i] ^ ak[i];
194 50 : os_memcpy(autn + 6, amf, 2);
195 50 : os_memcpy(autn + 8, mac_a, 8);
196 : }
197 :
198 :
199 : /**
200 : * milenage_auts - Milenage AUTS validation
201 : * @opc: OPc = 128-bit operator variant algorithm configuration field (encr.)
202 : * @k: K = 128-bit subscriber key
203 : * @_rand: RAND = 128-bit random challenge
204 : * @auts: AUTS = 112-bit authentication token from client
205 : * @sqn: Buffer for SQN = 48-bit sequence number
206 : * Returns: 0 = success (sqn filled), -1 on failure
207 : */
208 5 : int milenage_auts(const u8 *opc, const u8 *k, const u8 *_rand, const u8 *auts,
209 : u8 *sqn)
210 : {
211 5 : u8 amf[2] = { 0x00, 0x00 }; /* TS 33.102 v7.0.0, 6.3.3 */
212 : u8 ak[6], mac_s[8];
213 : int i;
214 :
215 5 : if (milenage_f2345(opc, k, _rand, NULL, NULL, NULL, NULL, ak))
216 0 : return -1;
217 35 : for (i = 0; i < 6; i++)
218 30 : sqn[i] = auts[i] ^ ak[i];
219 10 : if (milenage_f1(opc, k, _rand, sqn, amf, NULL, mac_s) ||
220 5 : os_memcmp_const(mac_s, auts + 6, 8) != 0)
221 1 : return -1;
222 4 : return 0;
223 : }
224 :
225 :
226 : /**
227 : * gsm_milenage - Generate GSM-Milenage (3GPP TS 55.205) authentication triplet
228 : * @opc: OPc = 128-bit operator variant algorithm configuration field (encr.)
229 : * @k: K = 128-bit subscriber key
230 : * @_rand: RAND = 128-bit random challenge
231 : * @sres: Buffer for SRES = 32-bit SRES
232 : * @kc: Buffer for Kc = 64-bit Kc
233 : * Returns: 0 on success, -1 on failure
234 : */
235 207 : int gsm_milenage(const u8 *opc, const u8 *k, const u8 *_rand, u8 *sres, u8 *kc)
236 : {
237 : u8 res[8], ck[16], ik[16];
238 : int i;
239 :
240 207 : if (milenage_f2345(opc, k, _rand, res, ck, ik, NULL, NULL))
241 12 : return -1;
242 :
243 1755 : for (i = 0; i < 8; i++)
244 1560 : kc[i] = ck[i] ^ ck[i + 8] ^ ik[i] ^ ik[i + 8];
245 :
246 : #ifdef GSM_MILENAGE_ALT_SRES
247 : os_memcpy(sres, res, 4);
248 : #else /* GSM_MILENAGE_ALT_SRES */
249 975 : for (i = 0; i < 4; i++)
250 780 : sres[i] = res[i] ^ res[i + 4];
251 : #endif /* GSM_MILENAGE_ALT_SRES */
252 195 : return 0;
253 : }
254 :
255 :
256 : /**
257 : * milenage_generate - Generate AKA AUTN,IK,CK,RES
258 : * @opc: OPc = 128-bit operator variant algorithm configuration field (encr.)
259 : * @k: K = 128-bit subscriber key
260 : * @sqn: SQN = 48-bit sequence number
261 : * @_rand: RAND = 128-bit random challenge
262 : * @autn: AUTN = 128-bit authentication token
263 : * @ik: Buffer for IK = 128-bit integrity key (f4), or %NULL
264 : * @ck: Buffer for CK = 128-bit confidentiality key (f3), or %NULL
265 : * @res: Buffer for RES = 64-bit signed response (f2), or %NULL
266 : * @res_len: Variable that will be set to RES length
267 : * @auts: 112-bit buffer for AUTS
268 : * Returns: 0 on success, -1 on failure, or -2 on synchronization failure
269 : */
270 37 : int milenage_check(const u8 *opc, const u8 *k, const u8 *sqn, const u8 *_rand,
271 : const u8 *autn, u8 *ik, u8 *ck, u8 *res, size_t *res_len,
272 : u8 *auts)
273 : {
274 : int i;
275 : u8 mac_a[8], ak[6], rx_sqn[6];
276 : const u8 *amf;
277 :
278 37 : wpa_hexdump(MSG_DEBUG, "Milenage: AUTN", autn, 16);
279 37 : wpa_hexdump(MSG_DEBUG, "Milenage: RAND", _rand, 16);
280 :
281 37 : if (milenage_f2345(opc, k, _rand, res, ck, ik, ak, NULL))
282 0 : return -1;
283 :
284 37 : *res_len = 8;
285 37 : wpa_hexdump_key(MSG_DEBUG, "Milenage: RES", res, *res_len);
286 37 : wpa_hexdump_key(MSG_DEBUG, "Milenage: CK", ck, 16);
287 37 : wpa_hexdump_key(MSG_DEBUG, "Milenage: IK", ik, 16);
288 37 : wpa_hexdump_key(MSG_DEBUG, "Milenage: AK", ak, 6);
289 :
290 : /* AUTN = (SQN ^ AK) || AMF || MAC */
291 259 : for (i = 0; i < 6; i++)
292 222 : rx_sqn[i] = autn[i] ^ ak[i];
293 37 : wpa_hexdump(MSG_DEBUG, "Milenage: SQN", rx_sqn, 6);
294 :
295 37 : if (os_memcmp(rx_sqn, sqn, 6) <= 0) {
296 4 : u8 auts_amf[2] = { 0x00, 0x00 }; /* TS 33.102 v7.0.0, 6.3.3 */
297 4 : if (milenage_f2345(opc, k, _rand, NULL, NULL, NULL, NULL, ak))
298 0 : return -1;
299 4 : wpa_hexdump_key(MSG_DEBUG, "Milenage: AK*", ak, 6);
300 28 : for (i = 0; i < 6; i++)
301 24 : auts[i] = sqn[i] ^ ak[i];
302 4 : if (milenage_f1(opc, k, _rand, sqn, auts_amf, NULL, auts + 6))
303 0 : return -1;
304 4 : wpa_hexdump(MSG_DEBUG, "Milenage: AUTS", auts, 14);
305 4 : return -2;
306 : }
307 :
308 33 : amf = autn + 6;
309 33 : wpa_hexdump(MSG_DEBUG, "Milenage: AMF", amf, 2);
310 33 : if (milenage_f1(opc, k, _rand, rx_sqn, amf, mac_a, NULL))
311 0 : return -1;
312 :
313 33 : wpa_hexdump(MSG_DEBUG, "Milenage: MAC_A", mac_a, 8);
314 :
315 33 : if (os_memcmp_const(mac_a, autn + 8, 8) != 0) {
316 3 : wpa_printf(MSG_DEBUG, "Milenage: MAC mismatch");
317 3 : wpa_hexdump(MSG_DEBUG, "Milenage: Received MAC_A",
318 : autn + 8, 8);
319 3 : return -1;
320 : }
321 :
322 30 : return 0;
323 : }
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