2 * EAP server/peer: EAP-SAKE 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.
13 #include "crypto/sha1.h"
15 #include "eap_sake_common.h"
18 static int eap_sake_parse_add_attr(struct eap_sake_parse_attr *attr,
19 u8 attr_id, u8 len, const u8 *data)
24 case EAP_SAKE_AT_RAND_S:
25 wpa_printf(MSG_DEBUG, "EAP-SAKE: Parse: AT_RAND_S");
26 if (len != EAP_SAKE_RAND_LEN) {
27 wpa_printf(MSG_DEBUG, "EAP-SAKE: AT_RAND_S with "
28 "invalid payload length %d", len);
33 case EAP_SAKE_AT_RAND_P:
34 wpa_printf(MSG_DEBUG, "EAP-SAKE: Parse: AT_RAND_P");
35 if (len != EAP_SAKE_RAND_LEN) {
36 wpa_printf(MSG_DEBUG, "EAP-SAKE: AT_RAND_P with "
37 "invalid payload length %d", len);
42 case EAP_SAKE_AT_MIC_S:
43 wpa_printf(MSG_DEBUG, "EAP-SAKE: Parse: AT_MIC_S");
44 if (len != EAP_SAKE_MIC_LEN) {
45 wpa_printf(MSG_DEBUG, "EAP-SAKE: AT_MIC_S with "
46 "invalid payload length %d", len);
51 case EAP_SAKE_AT_MIC_P:
52 wpa_printf(MSG_DEBUG, "EAP-SAKE: Parse: AT_MIC_P");
53 if (len != EAP_SAKE_MIC_LEN) {
54 wpa_printf(MSG_DEBUG, "EAP-SAKE: AT_MIC_P with "
55 "invalid payload length %d", len);
60 case EAP_SAKE_AT_SERVERID:
61 wpa_printf(MSG_DEBUG, "EAP-SAKE: Parse: AT_SERVERID");
62 attr->serverid = data;
63 attr->serverid_len = len;
65 case EAP_SAKE_AT_PEERID:
66 wpa_printf(MSG_DEBUG, "EAP-SAKE: Parse: AT_PEERID");
68 attr->peerid_len = len;
70 case EAP_SAKE_AT_SPI_S:
71 wpa_printf(MSG_DEBUG, "EAP-SAKE: Parse: AT_SPI_S");
73 attr->spi_s_len = len;
75 case EAP_SAKE_AT_SPI_P:
76 wpa_printf(MSG_DEBUG, "EAP-SAKE: Parse: AT_SPI_P");
78 attr->spi_p_len = len;
80 case EAP_SAKE_AT_ANY_ID_REQ:
81 wpa_printf(MSG_DEBUG, "EAP-SAKE: Parse: AT_ANY_ID_REQ");
83 wpa_printf(MSG_DEBUG, "EAP-SAKE: Invalid AT_ANY_ID_REQ"
84 " payload length %d", len);
87 attr->any_id_req = data;
89 case EAP_SAKE_AT_PERM_ID_REQ:
90 wpa_printf(MSG_DEBUG, "EAP-SAKE: Parse: AT_PERM_ID_REQ");
92 wpa_printf(MSG_DEBUG, "EAP-SAKE: Invalid "
93 "AT_PERM_ID_REQ payload length %d", len);
96 attr->perm_id_req = data;
98 case EAP_SAKE_AT_ENCR_DATA:
99 wpa_printf(MSG_DEBUG, "EAP-SAKE: Parse: AT_ENCR_DATA");
100 attr->encr_data = data;
101 attr->encr_data_len = len;
104 wpa_printf(MSG_DEBUG, "EAP-SAKE: Parse: AT_IV");
108 case EAP_SAKE_AT_PADDING:
109 wpa_printf(MSG_DEBUG, "EAP-SAKE: Parse: AT_PADDING");
110 for (i = 0; i < len; i++) {
112 wpa_printf(MSG_DEBUG, "EAP-SAKE: AT_PADDING "
113 "with non-zero pad byte");
118 case EAP_SAKE_AT_NEXT_TMPID:
119 wpa_printf(MSG_DEBUG, "EAP-SAKE: Parse: AT_NEXT_TMPID");
120 attr->next_tmpid = data;
121 attr->next_tmpid_len = len;
123 case EAP_SAKE_AT_MSK_LIFE:
124 wpa_printf(MSG_DEBUG, "EAP-SAKE: Parse: AT_IV");
126 wpa_printf(MSG_DEBUG, "EAP-SAKE: Invalid "
127 "AT_MSK_LIFE payload length %d", len);
130 attr->msk_life = data;
134 wpa_printf(MSG_DEBUG, "EAP-SAKE: Unknown non-skippable"
135 " attribute %d", attr_id);
138 wpa_printf(MSG_DEBUG, "EAP-SAKE: Ignoring unknown skippable "
139 "attribute %d", attr_id);
143 if (attr->iv && !attr->encr_data) {
144 wpa_printf(MSG_DEBUG, "EAP-SAKE: AT_IV included without "
154 * eap_sake_parse_attributes - Parse EAP-SAKE attributes
155 * @buf: Packet payload (starting with the first attribute)
156 * @len: Payload length
157 * @attr: Structure to be filled with found attributes
158 * Returns: 0 on success or -1 on failure
160 int eap_sake_parse_attributes(const u8 *buf, size_t len,
161 struct eap_sake_parse_attr *attr)
163 const u8 *pos = buf, *end = buf + len;
165 os_memset(attr, 0, sizeof(*attr));
168 wpa_printf(MSG_DEBUG, "EAP-SAKE: Too short attribute");
173 wpa_printf(MSG_DEBUG, "EAP-SAKE: Invalid attribute "
174 "length (%d)", pos[1]);
178 if (pos + pos[1] > end) {
179 wpa_printf(MSG_DEBUG, "EAP-SAKE: Attribute underflow");
183 if (eap_sake_parse_add_attr(attr, pos[0], pos[1] - 2, pos + 2))
194 * eap_sake_kdf - EAP-SAKE Key Derivation Function (KDF)
196 * @key_len: Length of the key in bytes
197 * @label: A unique label for each purpose of the KDF
198 * @data: Extra data (start) to bind into the key
199 * @data_len: Length of the data
200 * @data2: Extra data (end) to bind into the key
201 * @data2_len: Length of the data2
202 * @buf: Buffer for the generated pseudo-random key
203 * @buf_len: Number of bytes of key to generate
205 * This function is used to derive new, cryptographically separate keys from a
206 * given key (e.g., SMS). This is identical to the PRF used in IEEE 802.11i.
208 static void eap_sake_kdf(const u8 *key, size_t key_len, const char *label,
209 const u8 *data, size_t data_len,
210 const u8 *data2, size_t data2_len,
211 u8 *buf, size_t buf_len)
215 u8 hash[SHA1_MAC_LEN];
216 size_t label_len = os_strlen(label) + 1;
217 const unsigned char *addr[4];
220 addr[0] = (u8 *) label; /* Label | Y */
222 addr[1] = data; /* Msg[start] */
224 addr[2] = data2; /* Msg[end] */
226 addr[3] = &counter; /* Length */
230 while (pos < buf_len) {
231 plen = buf_len - pos;
232 if (plen >= SHA1_MAC_LEN) {
233 hmac_sha1_vector(key, key_len, 4, addr, len,
237 hmac_sha1_vector(key, key_len, 4, addr, len,
239 os_memcpy(&buf[pos], hash, plen);
248 * eap_sake_derive_keys - Derive EAP-SAKE keys
249 * @root_secret_a: 16-byte Root-Secret-A
250 * @root_secret_b: 16-byte Root-Secret-B
251 * @rand_s: 16-byte RAND_S
252 * @rand_p: 16-byte RAND_P
253 * @tek: Buffer for Temporary EAK Keys (TEK-Auth[16] | TEK-Cipher[16])
254 * @msk: Buffer for 64-byte MSK
255 * @emsk: Buffer for 64-byte EMSK
257 * This function derives EAP-SAKE keys as defined in RFC 4763, section 3.2.6.
259 void eap_sake_derive_keys(const u8 *root_secret_a, const u8 *root_secret_b,
260 const u8 *rand_s, const u8 *rand_p, u8 *tek, u8 *msk,
263 u8 sms_a[EAP_SAKE_SMS_LEN];
264 u8 sms_b[EAP_SAKE_SMS_LEN];
265 u8 key_buf[EAP_MSK_LEN + EAP_EMSK_LEN];
267 wpa_printf(MSG_DEBUG, "EAP-SAKE: Deriving keys");
269 wpa_hexdump_key(MSG_DEBUG, "EAP-SAKE: Root-Secret-A",
270 root_secret_a, EAP_SAKE_ROOT_SECRET_LEN);
271 eap_sake_kdf(root_secret_a, EAP_SAKE_ROOT_SECRET_LEN,
272 "SAKE Master Secret A",
273 rand_p, EAP_SAKE_RAND_LEN, rand_s, EAP_SAKE_RAND_LEN,
274 sms_a, EAP_SAKE_SMS_LEN);
275 wpa_hexdump_key(MSG_DEBUG, "EAP-SAKE: SMS-A", sms_a, EAP_SAKE_SMS_LEN);
276 eap_sake_kdf(sms_a, EAP_SAKE_SMS_LEN, "Transient EAP Key",
277 rand_s, EAP_SAKE_RAND_LEN, rand_p, EAP_SAKE_RAND_LEN,
278 tek, EAP_SAKE_TEK_LEN);
279 wpa_hexdump_key(MSG_DEBUG, "EAP-SAKE: TEK-Auth",
280 tek, EAP_SAKE_TEK_AUTH_LEN);
281 wpa_hexdump_key(MSG_DEBUG, "EAP-SAKE: TEK-Cipher",
282 tek + EAP_SAKE_TEK_AUTH_LEN, EAP_SAKE_TEK_CIPHER_LEN);
284 wpa_hexdump_key(MSG_DEBUG, "EAP-SAKE: Root-Secret-B",
285 root_secret_b, EAP_SAKE_ROOT_SECRET_LEN);
286 eap_sake_kdf(root_secret_b, EAP_SAKE_ROOT_SECRET_LEN,
287 "SAKE Master Secret B",
288 rand_p, EAP_SAKE_RAND_LEN, rand_s, EAP_SAKE_RAND_LEN,
289 sms_b, EAP_SAKE_SMS_LEN);
290 wpa_hexdump_key(MSG_DEBUG, "EAP-SAKE: SMS-B", sms_b, EAP_SAKE_SMS_LEN);
291 eap_sake_kdf(sms_b, EAP_SAKE_SMS_LEN, "Master Session Key",
292 rand_s, EAP_SAKE_RAND_LEN, rand_p, EAP_SAKE_RAND_LEN,
293 key_buf, sizeof(key_buf));
294 os_memcpy(msk, key_buf, EAP_MSK_LEN);
295 os_memcpy(emsk, key_buf + EAP_MSK_LEN, EAP_EMSK_LEN);
296 wpa_hexdump_key(MSG_DEBUG, "EAP-SAKE: MSK", msk, EAP_MSK_LEN);
297 wpa_hexdump_key(MSG_DEBUG, "EAP-SAKE: EMSK", emsk, EAP_EMSK_LEN);
302 * eap_sake_compute_mic - Compute EAP-SAKE MIC for an EAP packet
303 * @tek_auth: 16-byte TEK-Auth
304 * @rand_s: 16-byte RAND_S
305 * @rand_p: 16-byte RAND_P
306 * @serverid: SERVERID
307 * @serverid_len: SERVERID length
309 * @peerid_len: PEERID length
310 * @peer: MIC calculation for 0 = Server, 1 = Peer message
312 * @eap_len: EAP packet length
313 * @mic_pos: MIC position in the EAP packet (must be [eap .. eap + eap_len])
314 * @mic: Buffer for the computed 16-byte MIC
316 int eap_sake_compute_mic(const u8 *tek_auth,
317 const u8 *rand_s, const u8 *rand_p,
318 const u8 *serverid, size_t serverid_len,
319 const u8 *peerid, size_t peerid_len,
320 int peer, const u8 *eap, size_t eap_len,
321 const u8 *mic_pos, u8 *mic)
323 u8 _rand[2 * EAP_SAKE_RAND_LEN];
327 tmplen = serverid_len + 1 + peerid_len + 1 + eap_len;
328 tmp = os_malloc(tmplen);
334 os_memcpy(pos, peerid, peerid_len);
339 os_memcpy(pos, serverid, serverid_len);
344 os_memcpy(_rand, rand_s, EAP_SAKE_RAND_LEN);
345 os_memcpy(_rand + EAP_SAKE_RAND_LEN, rand_p,
349 os_memcpy(pos, serverid, serverid_len);
354 os_memcpy(pos, peerid, peerid_len);
359 os_memcpy(_rand, rand_p, EAP_SAKE_RAND_LEN);
360 os_memcpy(_rand + EAP_SAKE_RAND_LEN, rand_s,
364 os_memcpy(pos, eap, eap_len);
365 os_memset(pos + (mic_pos - eap), 0, EAP_SAKE_MIC_LEN);
367 eap_sake_kdf(tek_auth, EAP_SAKE_TEK_AUTH_LEN,
368 peer ? "Peer MIC" : "Server MIC",
369 _rand, 2 * EAP_SAKE_RAND_LEN, tmp, tmplen,
370 mic, EAP_SAKE_MIC_LEN);
378 void eap_sake_add_attr(struct wpabuf *buf, u8 type, const u8 *data,
381 wpabuf_put_u8(buf, type);
382 wpabuf_put_u8(buf, 2 + len); /* Length; including attr header */
384 wpabuf_put_data(buf, data, len);
386 os_memset(wpabuf_put(buf, len), 0, len);