2 * EAP peer method: EAP-PSK (RFC 4764)
3 * Copyright (c) 2004-2007, Jouni Malinen <j@w1.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.
14 * Note: EAP-PSK is an EAP authentication method and as such, completely
15 * different from WPA-PSK. This file is not needed for WPA-PSK functionality.
22 #include "config_ssid.h"
25 #include "eap_psk_common.h"
29 enum { PSK_INIT, PSK_MAC_SENT, PSK_DONE } state;
30 u8 rand_p[EAP_PSK_RAND_LEN];
31 u8 ak[EAP_PSK_AK_LEN], kdk[EAP_PSK_KDK_LEN], tek[EAP_PSK_TEK_LEN];
33 size_t id_s_len, id_p_len;
35 u8 emsk[EAP_EMSK_LEN];
39 static void * eap_psk_init(struct eap_sm *sm)
41 struct wpa_ssid *config = eap_get_config(sm);
42 struct eap_psk_data *data;
44 if (config == NULL || !config->eappsk) {
45 wpa_printf(MSG_INFO, "EAP-PSK: pre-shared key not configured");
49 data = os_zalloc(sizeof(*data));
52 eap_psk_key_setup(config->eappsk, data->ak, data->kdk);
53 wpa_hexdump_key(MSG_DEBUG, "EAP-PSK: AK", data->ak, EAP_PSK_AK_LEN);
54 wpa_hexdump_key(MSG_DEBUG, "EAP-PSK: KDK", data->kdk, EAP_PSK_KDK_LEN);
55 data->state = PSK_INIT;
58 data->id_p = os_malloc(config->nai_len);
60 os_memcpy(data->id_p, config->nai, config->nai_len);
61 data->id_p_len = config->nai_len;
63 if (data->id_p == NULL) {
64 wpa_printf(MSG_INFO, "EAP-PSK: could not get own identity");
73 static void eap_psk_deinit(struct eap_sm *sm, void *priv)
75 struct eap_psk_data *data = priv;
82 static u8 * eap_psk_process_1(struct eap_psk_data *data,
83 struct eap_method_ret *ret,
84 const u8 *reqData, size_t reqDataLen,
87 const struct eap_psk_hdr_1 *hdr1;
88 struct eap_psk_hdr_2 *hdr2;
92 wpa_printf(MSG_DEBUG, "EAP-PSK: in INIT state");
94 hdr1 = (const struct eap_psk_hdr_1 *) reqData;
95 if (reqDataLen < sizeof(*hdr1) ||
96 be_to_host16(hdr1->length) < sizeof(*hdr1) ||
97 be_to_host16(hdr1->length) > reqDataLen) {
98 wpa_printf(MSG_INFO, "EAP-PSK: Invalid first message "
99 "length (%lu %d; expected %lu or more)",
100 (unsigned long) reqDataLen,
101 be_to_host16(hdr1->length),
102 (unsigned long) sizeof(*hdr1));
106 wpa_printf(MSG_DEBUG, "EAP-PSK: Flags=0x%x", hdr1->flags);
107 if (EAP_PSK_FLAGS_GET_T(hdr1->flags) != 0) {
108 wpa_printf(MSG_INFO, "EAP-PSK: Unexpected T=%d (expected 0)",
109 EAP_PSK_FLAGS_GET_T(hdr1->flags));
110 ret->methodState = METHOD_DONE;
111 ret->decision = DECISION_FAIL;
114 wpa_hexdump(MSG_DEBUG, "EAP-PSK: RAND_S", hdr1->rand_s,
117 data->id_s_len = be_to_host16(hdr1->length) - sizeof(*hdr1);
118 data->id_s = os_malloc(data->id_s_len);
119 if (data->id_s == NULL) {
120 wpa_printf(MSG_ERROR, "EAP-PSK: Failed to allocate memory for "
121 "ID_S (len=%lu)", (unsigned long) data->id_s_len);
125 os_memcpy(data->id_s, (u8 *) (hdr1 + 1), data->id_s_len);
126 wpa_hexdump_ascii(MSG_DEBUG, "EAP-PSK: ID_S",
127 data->id_s, data->id_s_len);
129 if (hostapd_get_rand(data->rand_p, EAP_PSK_RAND_LEN)) {
130 wpa_printf(MSG_ERROR, "EAP-PSK: Failed to get random data");
135 *respDataLen = sizeof(*hdr2) + data->id_p_len;
136 resp = os_malloc(*respDataLen);
139 hdr2 = (struct eap_psk_hdr_2 *) resp;
140 hdr2->code = EAP_CODE_RESPONSE;
141 hdr2->identifier = hdr1->identifier;
142 hdr2->length = host_to_be16(*respDataLen);
143 hdr2->type = EAP_TYPE_PSK;
144 hdr2->flags = EAP_PSK_FLAGS_SET_T(1); /* T=1 */
145 os_memcpy(hdr2->rand_s, hdr1->rand_s, EAP_PSK_RAND_LEN);
146 os_memcpy(hdr2->rand_p, data->rand_p, EAP_PSK_RAND_LEN);
147 os_memcpy((u8 *) (hdr2 + 1), data->id_p, data->id_p_len);
148 /* MAC_P = OMAC1-AES-128(AK, ID_P||ID_S||RAND_S||RAND_P) */
149 buflen = data->id_p_len + data->id_s_len + 2 * EAP_PSK_RAND_LEN;
150 buf = os_malloc(buflen);
155 os_memcpy(buf, data->id_p, data->id_p_len);
156 pos = buf + data->id_p_len;
157 os_memcpy(pos, data->id_s, data->id_s_len);
158 pos += data->id_s_len;
159 os_memcpy(pos, hdr1->rand_s, EAP_PSK_RAND_LEN);
160 pos += EAP_PSK_RAND_LEN;
161 os_memcpy(pos, data->rand_p, EAP_PSK_RAND_LEN);
162 omac1_aes_128(data->ak, buf, buflen, hdr2->mac_p);
164 wpa_hexdump(MSG_DEBUG, "EAP-PSK: RAND_P", hdr2->rand_p,
166 wpa_hexdump(MSG_DEBUG, "EAP-PSK: MAC_P", hdr2->mac_p, EAP_PSK_MAC_LEN);
167 wpa_hexdump_ascii(MSG_DEBUG, "EAP-PSK: ID_P",
168 (u8 *) (hdr2 + 1), data->id_p_len);
170 data->state = PSK_MAC_SENT;
176 static u8 * eap_psk_process_3(struct eap_psk_data *data,
177 struct eap_method_ret *ret,
178 const u8 *reqData, size_t reqDataLen,
181 const struct eap_psk_hdr_3 *hdr3;
182 struct eap_psk_hdr_4 *hdr4;
183 u8 *resp, *buf, *rpchannel, nonce[16], *decrypted;
184 const u8 *pchannel, *tag, *msg;
185 u8 mac[EAP_PSK_MAC_LEN];
186 size_t buflen, left, data_len;
189 wpa_printf(MSG_DEBUG, "EAP-PSK: in MAC_SENT state");
191 hdr3 = (const struct eap_psk_hdr_3 *) reqData;
192 left = be_to_host16(hdr3->length);
193 if (left < sizeof(*hdr3) || reqDataLen < left) {
194 wpa_printf(MSG_INFO, "EAP-PSK: Invalid third message "
195 "length (%lu %d; expected %lu)",
196 (unsigned long) reqDataLen,
197 be_to_host16(hdr3->length),
198 (unsigned long) sizeof(*hdr3));
202 left -= sizeof(*hdr3);
203 pchannel = (const u8 *) (hdr3 + 1);
204 wpa_printf(MSG_DEBUG, "EAP-PSK: Flags=0x%x", hdr3->flags);
205 if (EAP_PSK_FLAGS_GET_T(hdr3->flags) != 2) {
206 wpa_printf(MSG_INFO, "EAP-PSK: Unexpected T=%d (expected 2)",
207 EAP_PSK_FLAGS_GET_T(hdr3->flags));
208 ret->methodState = METHOD_DONE;
209 ret->decision = DECISION_FAIL;
212 wpa_hexdump(MSG_DEBUG, "EAP-PSK: RAND_S", hdr3->rand_s,
214 wpa_hexdump(MSG_DEBUG, "EAP-PSK: MAC_S", hdr3->mac_s, EAP_PSK_MAC_LEN);
215 wpa_hexdump(MSG_DEBUG, "EAP-PSK: PCHANNEL", pchannel, left);
217 if (left < 4 + 16 + 1) {
218 wpa_printf(MSG_INFO, "EAP-PSK: Too short PCHANNEL data in "
219 "third message (len=%lu, expected 21)",
220 (unsigned long) left);
225 /* MAC_S = OMAC1-AES-128(AK, ID_S||RAND_P) */
226 buflen = data->id_s_len + EAP_PSK_RAND_LEN;
227 buf = os_malloc(buflen);
230 os_memcpy(buf, data->id_s, data->id_s_len);
231 os_memcpy(buf + data->id_s_len, data->rand_p, EAP_PSK_RAND_LEN);
232 omac1_aes_128(data->ak, buf, buflen, mac);
234 if (os_memcmp(mac, hdr3->mac_s, EAP_PSK_MAC_LEN) != 0) {
235 wpa_printf(MSG_WARNING, "EAP-PSK: Invalid MAC_S in third "
237 ret->methodState = METHOD_DONE;
238 ret->decision = DECISION_FAIL;
241 wpa_printf(MSG_DEBUG, "EAP-PSK: MAC_S verified successfully");
243 eap_psk_derive_keys(data->kdk, data->rand_p, data->tek,
244 data->msk, data->emsk);
245 wpa_hexdump_key(MSG_DEBUG, "EAP-PSK: TEK", data->tek, EAP_PSK_TEK_LEN);
246 wpa_hexdump_key(MSG_DEBUG, "EAP-PSK: MSK", data->msk, EAP_MSK_LEN);
247 wpa_hexdump_key(MSG_DEBUG, "EAP-PSK: EMSK", data->emsk, EAP_EMSK_LEN);
249 os_memset(nonce, 0, 12);
250 os_memcpy(nonce + 12, pchannel, 4);
260 wpa_hexdump(MSG_MSGDUMP, "EAP-PSK: PCHANNEL - nonce",
261 nonce, sizeof(nonce));
262 wpa_hexdump(MSG_MSGDUMP, "EAP-PSK: PCHANNEL - hdr", reqData, 5);
263 wpa_hexdump(MSG_MSGDUMP, "EAP-PSK: PCHANNEL - cipher msg", msg, left);
265 decrypted = os_malloc(left);
266 if (decrypted == NULL) {
267 ret->methodState = METHOD_DONE;
268 ret->decision = DECISION_FAIL;
271 os_memcpy(decrypted, msg, left);
273 if (aes_128_eax_decrypt(data->tek, nonce, sizeof(nonce),
274 reqData, 22, decrypted, left, tag)) {
275 wpa_printf(MSG_WARNING, "EAP-PSK: PCHANNEL decryption failed");
279 wpa_hexdump(MSG_DEBUG, "EAP-PSK: Decrypted PCHANNEL message",
283 switch (decrypted[0] >> 6) {
284 case EAP_PSK_R_FLAG_CONT:
285 wpa_printf(MSG_DEBUG, "EAP-PSK: R flag - CONT - unsupported");
288 case EAP_PSK_R_FLAG_DONE_SUCCESS:
289 wpa_printf(MSG_DEBUG, "EAP-PSK: R flag - DONE_SUCCESS");
291 case EAP_PSK_R_FLAG_DONE_FAILURE:
292 wpa_printf(MSG_DEBUG, "EAP-PSK: R flag - DONE_FAILURE");
293 wpa_printf(MSG_INFO, "EAP-PSK: Authentication server rejected "
299 *respDataLen = sizeof(*hdr4) + 4 + 16 + 1;
300 resp = os_malloc(*respDataLen + 1);
305 hdr4 = (struct eap_psk_hdr_4 *) resp;
306 hdr4->code = EAP_CODE_RESPONSE;
307 hdr4->identifier = hdr3->identifier;
308 hdr4->length = host_to_be16(*respDataLen);
309 hdr4->type = EAP_TYPE_PSK;
310 hdr4->flags = EAP_PSK_FLAGS_SET_T(3); /* T=3 */
311 os_memcpy(hdr4->rand_s, hdr3->rand_s, EAP_PSK_RAND_LEN);
312 rpchannel = (u8 *) (hdr4 + 1);
315 inc_byte_array(nonce, sizeof(nonce));
316 os_memcpy(rpchannel, nonce + 12, 4);
319 if (decrypted[0] & EAP_PSK_E_FLAG) {
320 wpa_printf(MSG_DEBUG, "EAP-PSK: Unsupported E (Ext) flag");
322 rpchannel[4 + 16] = (EAP_PSK_R_FLAG_DONE_FAILURE << 6) |
325 /* Add empty EXT_Payload with same EXT_Type */
327 hdr4->length = host_to_be16(*respDataLen);
328 rpchannel[4 + 16 + 1] = decrypted[1];
332 rpchannel[4 + 16] = EAP_PSK_R_FLAG_DONE_FAILURE << 6;
334 rpchannel[4 + 16] = EAP_PSK_R_FLAG_DONE_SUCCESS << 6;
336 wpa_hexdump(MSG_DEBUG, "EAP-PSK: reply message (plaintext)",
337 rpchannel + 4 + 16, data_len);
338 aes_128_eax_encrypt(data->tek, nonce, sizeof(nonce), resp, 22,
339 rpchannel + 4 + 16, data_len, rpchannel + 4);
340 wpa_hexdump(MSG_DEBUG, "EAP-PSK: reply message (PCHANNEL)",
341 rpchannel, 4 + 16 + data_len);
343 wpa_printf(MSG_DEBUG, "EAP-PSK: Completed %ssuccessfully",
345 data->state = PSK_DONE;
346 ret->methodState = METHOD_DONE;
347 ret->decision = failed ? DECISION_FAIL : DECISION_UNCOND_SUCC;
355 static u8 * eap_psk_process(struct eap_sm *sm, void *priv,
356 struct eap_method_ret *ret,
357 const u8 *reqData, size_t reqDataLen,
360 struct eap_psk_data *data = priv;
365 pos = eap_hdr_validate(EAP_VENDOR_IETF, EAP_TYPE_PSK,
366 reqData, reqDataLen, &len);
371 len += sizeof(struct eap_hdr) + 1;
374 ret->methodState = METHOD_MAY_CONT;
375 ret->decision = DECISION_FAIL;
376 ret->allowNotifications = TRUE;
378 switch (data->state) {
380 resp = eap_psk_process_1(data, ret, reqData, len,
384 resp = eap_psk_process_3(data, ret, reqData, len,
388 wpa_printf(MSG_DEBUG, "EAP-PSK: in DONE state - ignore "
389 "unexpected message");
394 if (ret->methodState == METHOD_DONE) {
395 ret->allowNotifications = FALSE;
402 static Boolean eap_psk_isKeyAvailable(struct eap_sm *sm, void *priv)
404 struct eap_psk_data *data = priv;
405 return data->state == PSK_DONE;
409 static u8 * eap_psk_getKey(struct eap_sm *sm, void *priv, size_t *len)
411 struct eap_psk_data *data = priv;
414 if (data->state != PSK_DONE)
417 key = os_malloc(EAP_MSK_LEN);
422 os_memcpy(key, data->msk, EAP_MSK_LEN);
428 static u8 * eap_psk_get_emsk(struct eap_sm *sm, void *priv, size_t *len)
430 struct eap_psk_data *data = priv;
433 if (data->state != PSK_DONE)
436 key = os_malloc(EAP_EMSK_LEN);
441 os_memcpy(key, data->emsk, EAP_EMSK_LEN);
447 int eap_peer_psk_register(void)
449 struct eap_method *eap;
452 eap = eap_peer_method_alloc(EAP_PEER_METHOD_INTERFACE_VERSION,
453 EAP_VENDOR_IETF, EAP_TYPE_PSK, "PSK");
457 eap->init = eap_psk_init;
458 eap->deinit = eap_psk_deinit;
459 eap->process = eap_psk_process;
460 eap->isKeyAvailable = eap_psk_isKeyAvailable;
461 eap->getKey = eap_psk_getKey;
462 eap->get_emsk = eap_psk_get_emsk;
464 ret = eap_peer_method_register(eap);
466 eap_peer_method_free(eap);