2
* EAP server/peer: EAP-GPSK shared routines
3
* Copyright (c) 2006, Jouni Malinen <jkmaline@cc.hut.fi>
5
* This program is free software; you can redistribute it and/or modify
6
* it under the terms of the GNU General Public License version 2 as
7
* published by the Free Software Foundation.
9
* Alternatively, this software may be distributed under the terms of BSD
12
* See README and COPYING for more details.
21
#include "eap_gpsk_common.h"
25
* eap_gpsk_supported_ciphersuite - Check whether ciphersuite is supported
26
* @vendor: CSuite/Vendor
27
* @specifier: CSuite/Specifier
28
* Returns: 1 if ciphersuite is support, or 0 if not
30
int eap_gpsk_supported_ciphersuite(int vendor, int specifier)
32
if (vendor == EAP_GPSK_VENDOR_IETF &&
33
specifier == EAP_GPSK_CIPHER_AES)
35
#ifdef EAP_GPSK_SHA256
36
if (vendor == EAP_GPSK_VENDOR_IETF &&
37
specifier == EAP_GPSK_CIPHER_SHA256)
39
#endif /* EAP_GPSK_SHA256 */
44
static int eap_gpsk_gkdf_aes(const u8 *psk, const u8 *data, size_t data_len,
48
size_t i, n, size, left, clen;
52
tmp = malloc(size + data_len + 2 + 2);
54
wpa_printf(MSG_DEBUG, "EAP-GPSK: Failed to allocate memory "
61
n = (len + size - 1) / size;
62
for (i = 1; i <= n; i++) {
66
memcpy(pos, data, data_len);
70
WPA_PUT_BE16(pos, len);
73
if (omac1_aes_128(psk, tmp, pos - tmp, tmp) < 0) {
77
clen = left > size ? size : left;
78
memcpy(opos, tmp, clen);
89
static int eap_gpsk_derive_keys_aes(const u8 *psk, size_t psk_len,
90
const u8 *seed, size_t seed_len,
91
u8 *msk, u8 *sk, size_t *sk_len,
92
u8 *pk, size_t *pk_len)
94
#define EAP_GPSK_SK_LEN_AES 16
95
#define EAP_GPSK_PK_LEN_AES 16
97
u8 kdf_out[EAP_MSK_LEN + EAP_EMSK_LEN + EAP_GPSK_SK_LEN_AES +
101
* MK = GKDF-16(PSK[0..15], seed)
102
* KDF_out = GKDF-160(MK, seed)
103
* MSK = KDF_out[0..63]
104
* EMSK = KDF_out[64..127]
105
* SK = KDF_out[128..143]
106
* PK = KDF_out[144..159]
107
* MID = GKDF-16(Zero-String, "Method ID" || EAP_Method_Type || seed)
111
wpa_printf(MSG_DEBUG, "EAP-GPSK: Too short PSK (len %d) for "
112
"AES-128 ciphersuite", psk_len);
116
if (eap_gpsk_gkdf_aes(psk, seed, seed_len, mk, sizeof(mk)) < 0)
118
wpa_hexdump_key(MSG_DEBUG, "EAP-GPSK: MK", mk, sizeof(mk));
120
if (eap_gpsk_gkdf_aes(mk, seed, seed_len, kdf_out, sizeof(kdf_out)) <
125
wpa_hexdump_key(MSG_DEBUG, "EAP-GPSK: MSK", pos, EAP_MSK_LEN);
126
memcpy(msk, pos, EAP_MSK_LEN);
129
wpa_hexdump_key(MSG_DEBUG, "EAP-GPSK: EMSK", pos, EAP_EMSK_LEN);
132
wpa_hexdump_key(MSG_DEBUG, "EAP-GPSK: SK", pos, EAP_GPSK_SK_LEN_AES);
133
memcpy(sk, pos, EAP_GPSK_SK_LEN_AES);
134
*sk_len = EAP_GPSK_SK_LEN_AES;
135
pos += EAP_GPSK_SK_LEN_AES;
137
wpa_hexdump_key(MSG_DEBUG, "EAP-GPSK: PK", pos, EAP_GPSK_PK_LEN_AES);
138
memcpy(pk, pos, EAP_GPSK_PK_LEN_AES);
139
*pk_len = EAP_GPSK_PK_LEN_AES;
145
#ifdef EAP_GPSK_SHA256
146
static int eap_gpsk_gkdf_sha256(const u8 *psk, size_t psk_len,
147
const u8 *data, size_t data_len,
150
u8 *tmp, *pos, *opos;
151
size_t i, n, size, left, clen;
152
u8 ibuf[2], lenbuf[2], hash[SHA256_MAC_LEN];
156
size = SHA256_MAC_LEN;
162
vlen[2] = sizeof(ibuf);
164
vlen[3] = sizeof(lenbuf);
168
n = (len + size - 1) / size;
169
for (i = 1; i <= n; i++) {
172
hmac_sha256_vector(psk, psk_len, 4, addr, vlen, hash);
174
hmac_sha256_vector(psk, psk_len, 3, addr + 1, vlen + 1,
177
clen = left > size ? size : left;
178
memcpy(opos, hash, clen);
187
static int eap_gpsk_derive_keys_sha256(const u8 *psk, size_t psk_len,
188
const u8 *seed, size_t seed_len,
189
u8 *msk, u8 *sk, size_t *sk_len,
190
u8 *pk, size_t *pk_len)
192
#define EAP_GPSK_SK_LEN_SHA256 SHA256_MAC_LEN
193
#define EAP_GPSK_PK_LEN_SHA256 SHA256_MAC_LEN
194
u8 mk[SHA256_MAC_LEN], *pos;
195
u8 kdf_out[EAP_MSK_LEN + EAP_EMSK_LEN + EAP_GPSK_SK_LEN_SHA256 +
196
EAP_GPSK_PK_LEN_SHA256];
199
* MK = GKDF-32(PSK, seed || CSuite_Sel)
200
* KDF_out = GKDF-192(MK, seed)
201
* MSK = KDF_out[0..63]
202
* EMSK = KDF_out[64..127]
203
* SK = KDF_out[128..159]
204
* PK = KDF_out[160..191]
205
* MID = GKDF-16(Zero-String, "Method ID" || EAP_Method_Type || seed)
208
if (eap_gpsk_gkdf_sha256(psk, psk_len, seed, seed_len, mk, sizeof(mk))
211
wpa_hexdump_key(MSG_DEBUG, "EAP-GPSK: MK", mk, sizeof(mk));
213
if (eap_gpsk_gkdf_sha256(mk, sizeof(mk), seed, seed_len,
214
kdf_out, sizeof(kdf_out)) < 0)
218
wpa_hexdump_key(MSG_DEBUG, "EAP-GPSK: MSK", pos, EAP_MSK_LEN);
219
memcpy(msk, pos, EAP_MSK_LEN);
222
wpa_hexdump_key(MSG_DEBUG, "EAP-GPSK: EMSK", pos, EAP_EMSK_LEN);
225
wpa_hexdump_key(MSG_DEBUG, "EAP-GPSK: SK",
226
pos, EAP_GPSK_SK_LEN_SHA256);
227
memcpy(sk, pos, EAP_GPSK_SK_LEN_SHA256);
228
*sk_len = EAP_GPSK_SK_LEN_AES;
229
pos += EAP_GPSK_SK_LEN_AES;
231
wpa_hexdump_key(MSG_DEBUG, "EAP-GPSK: PK",
232
pos, EAP_GPSK_PK_LEN_SHA256);
233
memcpy(pk, pos, EAP_GPSK_PK_LEN_SHA256);
234
*pk_len = EAP_GPSK_PK_LEN_SHA256;
238
#endif /* EAP_GPSK_SHA256 */
242
* eap_gpsk_derive_keys - Derive EAP-GPSK keys
243
* @psk: Pre-shared key (at least 16 bytes if AES is used)
244
* @psk_len: Length of psk in bytes
245
* @vendor: CSuite/Vendor
246
* @specifier: CSuite/Specifier
247
* @rand_client: 32-byte RAND_Client
248
* @rand_server: 32-byte RAND_Server
249
* @id_client: ID_Client
250
* @id_client_len: Length of ID_Client
251
* @id_server: ID_Server
252
* @id_server_len: Length of ID_Server
253
* @msk: Buffer for 64-byte MSK
254
* @sk: Buffer for SK (at least EAP_GPSK_MAX_SK_LEN bytes)
255
* @sk_len: Buffer for returning length of SK
256
* @pk: Buffer for SK (at least EAP_GPSK_MAX_PK_LEN bytes)
257
* @pk_len: Buffer for returning length of PK
258
* Returns: 0 on success, -1 on failure
260
int eap_gpsk_derive_keys(const u8 *psk, size_t psk_len, int vendor,
262
const u8 *rand_client, const u8 *rand_server,
263
const u8 *id_client, size_t id_client_len,
264
const u8 *id_server, size_t id_server_len,
265
u8 *msk, u8 *sk, size_t *sk_len,
266
u8 *pk, size_t *pk_len)
272
wpa_printf(MSG_DEBUG, "EAP-GPSK: Deriving keys (%d:%d)",
275
if (vendor != EAP_GPSK_VENDOR_IETF)
278
wpa_hexdump_key(MSG_DEBUG, "EAP-GPSK: PSK", psk, psk_len);
280
/* Seed = RAND_Client || RAND_Server || ID_Server || IN_Client */
281
seed_len = 2 * EAP_GPSK_RAND_LEN + id_server_len + id_client_len;
282
seed = malloc(seed_len);
284
wpa_printf(MSG_DEBUG, "EAP-GPSK: Failed to allocate memory "
285
"for key derivation");
290
memcpy(pos, rand_client, EAP_GPSK_RAND_LEN);
291
pos += EAP_GPSK_RAND_LEN;
292
memcpy(pos, rand_server, EAP_GPSK_RAND_LEN);
293
pos += EAP_GPSK_RAND_LEN;
294
memcpy(pos, id_server, id_server_len);
295
pos += id_server_len;
296
memcpy(pos, id_client, id_client_len);
297
pos += id_client_len;
298
wpa_hexdump(MSG_DEBUG, "EAP-GPSK: Seed", seed, seed_len);
301
case EAP_GPSK_CIPHER_AES:
302
ret = eap_gpsk_derive_keys_aes(psk, psk_len, seed, seed_len,
303
msk, sk, sk_len, pk, pk_len);
305
#ifdef EAP_GPSK_SHA256
306
case EAP_GPSK_CIPHER_SHA256:
307
ret = eap_gpsk_derive_keys_sha256(psk, psk_len, seed, seed_len,
308
msk, sk, sk_len, pk, pk_len);
310
#endif /* EAP_GPSK_SHA256 */
312
wpa_printf(MSG_DEBUG, "EAP-GPSK: Unknown cipher %d:%d used in "
313
"key derivation", vendor, specifier);
325
* eap_gpsk_mic_len - Get the length of the MIC
326
* @vendor: CSuite/Vendor
327
* @specifier: CSuite/Specifier
328
* Returns: MIC length in bytes
330
size_t eap_gpsk_mic_len(int vendor, int specifier)
332
if (vendor != EAP_GPSK_VENDOR_IETF)
336
case EAP_GPSK_CIPHER_AES:
338
#ifdef EAP_GPSK_SHA256
339
case EAP_GPSK_CIPHER_SHA256:
341
#endif /* EAP_GPSK_SHA256 */
348
static int eap_gpsk_compute_mic_aes(const u8 *sk, size_t sk_len,
349
const u8 *data, size_t len, u8 *mic)
352
wpa_printf(MSG_DEBUG, "EAP-GPSK: Invalid SK length %d for "
353
"AES-CMAC MIC", sk_len);
357
return omac1_aes_128(sk, data, len, mic);
362
* eap_gpsk_compute_mic - Compute EAP-GPSK MIC for an EAP packet
363
* @sk: Session key SK from eap_gpsk_derive_keys()
364
* @sk_len: SK length in bytes from eap_gpsk_derive_keys()
365
* @vendor: CSuite/Vendor
366
* @specifier: CSuite/Specifier
367
* @data: Input data to MIC
368
* @len: Input data length in bytes
369
* @mic: Buffer for the computed MIC, eap_gpsk_mic_len(cipher) bytes
370
* Returns: 0 on success, -1 on failure
372
int eap_gpsk_compute_mic(const u8 *sk, size_t sk_len, int vendor,
373
int specifier, const u8 *data, size_t len, u8 *mic)
377
if (vendor != EAP_GPSK_VENDOR_IETF)
381
case EAP_GPSK_CIPHER_AES:
382
ret = eap_gpsk_compute_mic_aes(sk, sk_len, data, len, mic);
384
#ifdef EAP_GPSK_SHA256
385
case EAP_GPSK_CIPHER_SHA256:
386
hmac_sha256(sk, sk_len, data, len, mic);
389
#endif /* EAP_GPSK_SHA256 */
391
wpa_printf(MSG_DEBUG, "EAP-GPSK: Unknown cipher %d:%d used in "
392
"MIC computation", vendor, specifier);