2 * EAP server/peer: EAP-GPSK shared routines
3 * Copyright (c) 2006-2007, Jouni Malinen <j@w1.fi>
5 * This software may be distributed under the terms of the BSD license.
6 * See README for more details.
12 #include "crypto/aes_wrap.h"
13 #include "crypto/sha256.h"
15 #include "eap_gpsk_common.h"
19 * eap_gpsk_supported_ciphersuite - Check whether ciphersuite is supported
20 * @vendor: CSuite/Vendor
21 * @specifier: CSuite/Specifier
22 * Returns: 1 if ciphersuite is support, or 0 if not
24 int eap_gpsk_supported_ciphersuite(int vendor, int specifier)
26 if (vendor == EAP_GPSK_VENDOR_IETF &&
27 specifier == EAP_GPSK_CIPHER_AES)
29 #ifdef EAP_GPSK_SHA256
30 if (vendor == EAP_GPSK_VENDOR_IETF &&
31 specifier == EAP_GPSK_CIPHER_SHA256)
33 #endif /* EAP_GPSK_SHA256 */
38 static int eap_gpsk_gkdf_cmac(const u8 *psk /* Y */,
39 const u8 *data /* Z */, size_t data_len,
40 u8 *buf, size_t len /* X */)
43 size_t i, n, hashlen, left, clen;
48 hashlen = sizeof(hash);
49 /* M_i = MAC_Y (i || Z); (MAC = AES-CMAC-128) */
51 vlen[0] = sizeof(ibuf);
57 n = (len + hashlen - 1) / hashlen;
58 for (i = 1; i <= n; i++) {
59 WPA_PUT_BE16(ibuf, i);
60 if (omac1_aes_128_vector(psk, 2, addr, vlen, hash))
62 clen = left > hashlen ? hashlen : left;
63 os_memcpy(opos, hash, clen);
72 #ifdef EAP_GPSK_SHA256
73 static int eap_gpsk_gkdf_sha256(const u8 *psk /* Y */,
74 const u8 *data /* Z */, size_t data_len,
75 u8 *buf, size_t len /* X */)
78 size_t i, n, hashlen, left, clen;
79 u8 ibuf[2], hash[SHA256_MAC_LEN];
83 hashlen = SHA256_MAC_LEN;
84 /* M_i = MAC_Y (i || Z); (MAC = HMAC-SHA256) */
86 vlen[0] = sizeof(ibuf);
92 n = (len + hashlen - 1) / hashlen;
93 for (i = 1; i <= n; i++) {
94 WPA_PUT_BE16(ibuf, i);
95 hmac_sha256_vector(psk, 32, 2, addr, vlen, hash);
96 clen = left > hashlen ? hashlen : left;
97 os_memcpy(opos, hash, clen);
104 #endif /* EAP_GPSK_SHA256 */
107 static int eap_gpsk_derive_keys_helper(u32 csuite_specifier,
108 u8 *kdf_out, size_t kdf_out_len,
109 const u8 *psk, size_t psk_len,
110 const u8 *seed, size_t seed_len,
112 u8 *sk, size_t sk_len,
113 u8 *pk, size_t pk_len)
115 u8 mk[32], *pos, *data;
116 size_t data_len, mk_len;
117 int (*gkdf)(const u8 *_psk, const u8 *_data, size_t _data_len,
118 u8 *buf, size_t len);
121 switch (csuite_specifier) {
122 case EAP_GPSK_CIPHER_AES:
123 gkdf = eap_gpsk_gkdf_cmac;
126 #ifdef EAP_GPSK_SHA256
127 case EAP_GPSK_CIPHER_SHA256:
128 gkdf = eap_gpsk_gkdf_sha256;
129 mk_len = SHA256_MAC_LEN;
131 #endif /* EAP_GPSK_SHA256 */
136 if (psk_len < mk_len)
139 data_len = 2 + psk_len + 6 + seed_len;
140 data = os_malloc(data_len);
144 WPA_PUT_BE16(pos, psk_len);
146 os_memcpy(pos, psk, psk_len);
148 WPA_PUT_BE32(pos, EAP_GPSK_VENDOR_IETF); /* CSuite/Vendor = IETF */
150 WPA_PUT_BE16(pos, csuite_specifier); /* CSuite/Specifier */
152 os_memcpy(pos, seed, seed_len); /* inputString */
153 wpa_hexdump_key(MSG_DEBUG, "EAP-GPSK: Data to MK derivation",
156 if (gkdf(psk, data, data_len, mk, mk_len) < 0) {
161 wpa_hexdump_key(MSG_DEBUG, "EAP-GPSK: MK", mk, mk_len);
163 if (gkdf(mk, seed, seed_len, kdf_out, kdf_out_len) < 0)
167 wpa_hexdump_key(MSG_DEBUG, "EAP-GPSK: MSK", pos, EAP_MSK_LEN);
168 os_memcpy(msk, pos, EAP_MSK_LEN);
171 wpa_hexdump_key(MSG_DEBUG, "EAP-GPSK: EMSK", pos, EAP_EMSK_LEN);
172 os_memcpy(emsk, pos, EAP_EMSK_LEN);
175 wpa_hexdump_key(MSG_DEBUG, "EAP-GPSK: SK", pos, sk_len);
176 os_memcpy(sk, pos, sk_len);
180 wpa_hexdump_key(MSG_DEBUG, "EAP-GPSK: PK", pos, pk_len);
181 os_memcpy(pk, pos, pk_len);
188 static int eap_gpsk_derive_keys_aes(const u8 *psk, size_t psk_len,
189 const u8 *seed, size_t seed_len,
190 u8 *msk, u8 *emsk, u8 *sk, size_t *sk_len,
191 u8 *pk, size_t *pk_len)
193 #define EAP_GPSK_SK_LEN_AES 16
194 #define EAP_GPSK_PK_LEN_AES 16
195 u8 kdf_out[EAP_MSK_LEN + EAP_EMSK_LEN + EAP_GPSK_SK_LEN_AES +
196 EAP_GPSK_PK_LEN_AES];
199 * inputString = RAND_Peer || ID_Peer || RAND_Server || ID_Server
201 * KS = 16, PL = psk_len, CSuite_Sel = 0x00000000 0x0001
202 * MK = GKDF-16 (PSK[0..15], PL || PSK || CSuite_Sel || inputString)
203 * MSK = GKDF-160 (MK, inputString)[0..63]
204 * EMSK = GKDF-160 (MK, inputString)[64..127]
205 * SK = GKDF-160 (MK, inputString)[128..143]
206 * PK = GKDF-160 (MK, inputString)[144..159]
207 * zero = 0x00 || 0x00 || ... || 0x00 (16 times)
208 * Method-ID = GKDF-16 (zero, "Method ID" || EAP_Method_Type ||
209 * CSuite_Sel || inputString)
212 *sk_len = EAP_GPSK_SK_LEN_AES;
213 *pk_len = EAP_GPSK_PK_LEN_AES;
215 return eap_gpsk_derive_keys_helper(EAP_GPSK_CIPHER_AES,
216 kdf_out, sizeof(kdf_out),
217 psk, psk_len, seed, seed_len,
218 msk, emsk, sk, *sk_len,
223 #ifdef EAP_GPSK_SHA256
224 static int eap_gpsk_derive_keys_sha256(const u8 *psk, size_t psk_len,
225 const u8 *seed, size_t seed_len,
227 u8 *sk, size_t *sk_len)
229 #define EAP_GPSK_SK_LEN_SHA256 SHA256_MAC_LEN
230 #define EAP_GPSK_PK_LEN_SHA256 SHA256_MAC_LEN
231 u8 kdf_out[EAP_MSK_LEN + EAP_EMSK_LEN + EAP_GPSK_SK_LEN_SHA256 +
232 EAP_GPSK_PK_LEN_SHA256];
235 * inputString = RAND_Peer || ID_Peer || RAND_Server || ID_Server
237 * KS = 32, PL = psk_len, CSuite_Sel = 0x00000000 0x0002
238 * MK = GKDF-32 (PSK[0..31], PL || PSK || CSuite_Sel || inputString)
239 * MSK = GKDF-160 (MK, inputString)[0..63]
240 * EMSK = GKDF-160 (MK, inputString)[64..127]
241 * SK = GKDF-160 (MK, inputString)[128..159]
242 * zero = 0x00 || 0x00 || ... || 0x00 (32 times)
243 * Method-ID = GKDF-16 (zero, "Method ID" || EAP_Method_Type ||
244 * CSuite_Sel || inputString)
247 *sk_len = EAP_GPSK_SK_LEN_SHA256;
249 return eap_gpsk_derive_keys_helper(EAP_GPSK_CIPHER_SHA256,
250 kdf_out, sizeof(kdf_out),
251 psk, psk_len, seed, seed_len,
252 msk, emsk, sk, *sk_len,
255 #endif /* EAP_GPSK_SHA256 */
259 * eap_gpsk_derive_keys - Derive EAP-GPSK keys
260 * @psk: Pre-shared key
261 * @psk_len: Length of psk in bytes
262 * @vendor: CSuite/Vendor
263 * @specifier: CSuite/Specifier
264 * @rand_peer: 32-byte RAND_Peer
265 * @rand_server: 32-byte RAND_Server
267 * @id_peer_len: Length of ID_Peer
268 * @id_server: ID_Server
269 * @id_server_len: Length of ID_Server
270 * @msk: Buffer for 64-byte MSK
271 * @emsk: Buffer for 64-byte EMSK
272 * @sk: Buffer for SK (at least EAP_GPSK_MAX_SK_LEN bytes)
273 * @sk_len: Buffer for returning length of SK
274 * @pk: Buffer for PK (at least EAP_GPSK_MAX_PK_LEN bytes)
275 * @pk_len: Buffer for returning length of PK
276 * Returns: 0 on success, -1 on failure
278 int eap_gpsk_derive_keys(const u8 *psk, size_t psk_len, int vendor,
280 const u8 *rand_peer, const u8 *rand_server,
281 const u8 *id_peer, size_t id_peer_len,
282 const u8 *id_server, size_t id_server_len,
283 u8 *msk, u8 *emsk, u8 *sk, size_t *sk_len,
284 u8 *pk, size_t *pk_len)
290 wpa_printf(MSG_DEBUG, "EAP-GPSK: Deriving keys (%d:%d)",
293 if (vendor != EAP_GPSK_VENDOR_IETF)
296 wpa_hexdump_key(MSG_DEBUG, "EAP-GPSK: PSK", psk, psk_len);
298 /* Seed = RAND_Peer || ID_Peer || RAND_Server || ID_Server */
299 seed_len = 2 * EAP_GPSK_RAND_LEN + id_server_len + id_peer_len;
300 seed = os_malloc(seed_len);
302 wpa_printf(MSG_DEBUG, "EAP-GPSK: Failed to allocate memory "
303 "for key derivation");
308 os_memcpy(pos, rand_peer, EAP_GPSK_RAND_LEN);
309 pos += EAP_GPSK_RAND_LEN;
310 os_memcpy(pos, id_peer, id_peer_len);
312 os_memcpy(pos, rand_server, EAP_GPSK_RAND_LEN);
313 pos += EAP_GPSK_RAND_LEN;
314 os_memcpy(pos, id_server, id_server_len);
315 pos += id_server_len;
316 wpa_hexdump(MSG_DEBUG, "EAP-GPSK: Seed", seed, seed_len);
319 case EAP_GPSK_CIPHER_AES:
320 ret = eap_gpsk_derive_keys_aes(psk, psk_len, seed, seed_len,
321 msk, emsk, sk, sk_len,
324 #ifdef EAP_GPSK_SHA256
325 case EAP_GPSK_CIPHER_SHA256:
326 ret = eap_gpsk_derive_keys_sha256(psk, psk_len, seed, seed_len,
327 msk, emsk, sk, sk_len);
329 #endif /* EAP_GPSK_SHA256 */
331 wpa_printf(MSG_DEBUG, "EAP-GPSK: Unknown cipher %d:%d used in "
332 "key derivation", vendor, specifier);
344 * eap_gpsk_mic_len - Get the length of the MIC
345 * @vendor: CSuite/Vendor
346 * @specifier: CSuite/Specifier
347 * Returns: MIC length in bytes
349 size_t eap_gpsk_mic_len(int vendor, int specifier)
351 if (vendor != EAP_GPSK_VENDOR_IETF)
355 case EAP_GPSK_CIPHER_AES:
357 #ifdef EAP_GPSK_SHA256
358 case EAP_GPSK_CIPHER_SHA256:
360 #endif /* EAP_GPSK_SHA256 */
367 static int eap_gpsk_compute_mic_aes(const u8 *sk, size_t sk_len,
368 const u8 *data, size_t len, u8 *mic)
371 wpa_printf(MSG_DEBUG, "EAP-GPSK: Invalid SK length %lu for "
372 "AES-CMAC MIC", (unsigned long) sk_len);
376 return omac1_aes_128(sk, data, len, mic);
381 * eap_gpsk_compute_mic - Compute EAP-GPSK MIC for an EAP packet
382 * @sk: Session key SK from eap_gpsk_derive_keys()
383 * @sk_len: SK length in bytes from eap_gpsk_derive_keys()
384 * @vendor: CSuite/Vendor
385 * @specifier: CSuite/Specifier
386 * @data: Input data to MIC
387 * @len: Input data length in bytes
388 * @mic: Buffer for the computed MIC, eap_gpsk_mic_len(cipher) bytes
389 * Returns: 0 on success, -1 on failure
391 int eap_gpsk_compute_mic(const u8 *sk, size_t sk_len, int vendor,
392 int specifier, const u8 *data, size_t len, u8 *mic)
396 if (vendor != EAP_GPSK_VENDOR_IETF)
400 case EAP_GPSK_CIPHER_AES:
401 ret = eap_gpsk_compute_mic_aes(sk, sk_len, data, len, mic);
403 #ifdef EAP_GPSK_SHA256
404 case EAP_GPSK_CIPHER_SHA256:
405 hmac_sha256(sk, sk_len, data, len, mic);
408 #endif /* EAP_GPSK_SHA256 */
410 wpa_printf(MSG_DEBUG, "EAP-GPSK: Unknown cipher %d:%d used in "
411 "MIC computation", vendor, specifier);