2 * EAP peer method: EAP-PSK (RFC 4764)
3 * Copyright (c) 2004-2008, Jouni Malinen <j@w1.fi>
5 * This software may be distributed under the terms of the BSD license.
6 * See README for more details.
8 * Note: EAP-PSK is an EAP authentication method and as such, completely
9 * different from WPA-PSK. This file is not needed for WPA-PSK functionality.
15 #include "crypto/aes_wrap.h"
16 #include "crypto/random.h"
17 #include "eap_common/eap_psk_common.h"
22 enum { PSK_INIT, PSK_MAC_SENT, PSK_DONE } state;
23 u8 rand_p[EAP_PSK_RAND_LEN];
24 u8 rand_s[EAP_PSK_RAND_LEN];
25 u8 ak[EAP_PSK_AK_LEN], kdk[EAP_PSK_KDK_LEN], tek[EAP_PSK_TEK_LEN];
27 size_t id_s_len, id_p_len;
29 u8 emsk[EAP_EMSK_LEN];
33 static void * eap_psk_init(struct eap_sm *sm)
35 struct eap_psk_data *data;
36 const u8 *identity, *password;
37 size_t identity_len, password_len;
39 password = eap_get_config_password(sm, &password_len);
40 if (!password || password_len != 16) {
41 wpa_printf(MSG_INFO, "EAP-PSK: 16-octet pre-shared key not "
46 data = os_zalloc(sizeof(*data));
49 if (eap_psk_key_setup(password, 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;
57 identity = eap_get_config_identity(sm, &identity_len);
59 data->id_p = os_malloc(identity_len);
61 os_memcpy(data->id_p, identity, identity_len);
62 data->id_p_len = identity_len;
64 if (data->id_p == NULL) {
65 wpa_printf(MSG_INFO, "EAP-PSK: could not get own identity");
74 static void eap_psk_deinit(struct eap_sm *sm, void *priv)
76 struct eap_psk_data *data = priv;
79 bin_clear_free(data, sizeof(*data));
83 static struct wpabuf * eap_psk_process_1(struct eap_psk_data *data,
84 struct eap_method_ret *ret,
85 const struct wpabuf *reqData)
87 const struct eap_psk_hdr_1 *hdr1;
88 struct eap_psk_hdr_2 *hdr2;
94 wpa_printf(MSG_DEBUG, "EAP-PSK: in INIT state");
96 cpos = eap_hdr_validate(EAP_VENDOR_IETF, EAP_TYPE_PSK, reqData, &len);
97 hdr1 = (const struct eap_psk_hdr_1 *) cpos;
98 if (cpos == NULL || len < sizeof(*hdr1)) {
99 wpa_printf(MSG_INFO, "EAP-PSK: Invalid first message "
100 "length (%lu; expected %lu or more)",
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,
116 os_memcpy(data->rand_s, hdr1->rand_s, EAP_PSK_RAND_LEN);
118 data->id_s_len = len - sizeof(*hdr1);
119 data->id_s = os_malloc(data->id_s_len);
120 if (data->id_s == NULL) {
121 wpa_printf(MSG_ERROR, "EAP-PSK: Failed to allocate memory for "
122 "ID_S (len=%lu)", (unsigned long) data->id_s_len);
126 os_memcpy(data->id_s, (u8 *) (hdr1 + 1), data->id_s_len);
127 wpa_hexdump_ascii(MSG_DEBUG, "EAP-PSK: ID_S",
128 data->id_s, data->id_s_len);
130 if (random_get_bytes(data->rand_p, EAP_PSK_RAND_LEN)) {
131 wpa_printf(MSG_ERROR, "EAP-PSK: Failed to get random data");
136 resp = eap_msg_alloc(EAP_VENDOR_IETF, EAP_TYPE_PSK,
137 sizeof(*hdr2) + data->id_p_len, EAP_CODE_RESPONSE,
138 eap_get_id(reqData));
141 hdr2 = wpabuf_put(resp, sizeof(*hdr2));
142 hdr2->flags = EAP_PSK_FLAGS_SET_T(1); /* T=1 */
143 os_memcpy(hdr2->rand_s, hdr1->rand_s, EAP_PSK_RAND_LEN);
144 os_memcpy(hdr2->rand_p, data->rand_p, EAP_PSK_RAND_LEN);
145 wpabuf_put_data(resp, data->id_p, data->id_p_len);
146 /* MAC_P = OMAC1-AES-128(AK, ID_P||ID_S||RAND_S||RAND_P) */
147 buflen = data->id_p_len + data->id_s_len + 2 * EAP_PSK_RAND_LEN;
148 buf = os_malloc(buflen);
153 os_memcpy(buf, data->id_p, data->id_p_len);
154 pos = buf + data->id_p_len;
155 os_memcpy(pos, data->id_s, data->id_s_len);
156 pos += data->id_s_len;
157 os_memcpy(pos, hdr1->rand_s, EAP_PSK_RAND_LEN);
158 pos += EAP_PSK_RAND_LEN;
159 os_memcpy(pos, data->rand_p, EAP_PSK_RAND_LEN);
160 if (omac1_aes_128(data->ak, buf, buflen, hdr2->mac_p)) {
166 wpa_hexdump(MSG_DEBUG, "EAP-PSK: RAND_P", hdr2->rand_p,
168 wpa_hexdump(MSG_DEBUG, "EAP-PSK: MAC_P", hdr2->mac_p, EAP_PSK_MAC_LEN);
169 wpa_hexdump_ascii(MSG_DEBUG, "EAP-PSK: ID_P",
170 data->id_p, data->id_p_len);
172 data->state = PSK_MAC_SENT;
178 static struct wpabuf * eap_psk_process_3(struct eap_psk_data *data,
179 struct eap_method_ret *ret,
180 const struct wpabuf *reqData)
182 const struct eap_psk_hdr_3 *hdr3;
183 struct eap_psk_hdr_4 *hdr4;
185 u8 *buf, *rpchannel, nonce[16], *decrypted;
186 const u8 *pchannel, *tag, *msg;
187 u8 mac[EAP_PSK_MAC_LEN];
188 size_t buflen, left, data_len, len, plen;
192 wpa_printf(MSG_DEBUG, "EAP-PSK: in MAC_SENT state");
194 pos = eap_hdr_validate(EAP_VENDOR_IETF, EAP_TYPE_PSK,
196 hdr3 = (const struct eap_psk_hdr_3 *) pos;
197 if (pos == NULL || len < sizeof(*hdr3)) {
198 wpa_printf(MSG_INFO, "EAP-PSK: Invalid third message "
199 "length (%lu; expected %lu or more)",
201 (unsigned long) sizeof(*hdr3));
205 left = len - sizeof(*hdr3);
206 pchannel = (const u8 *) (hdr3 + 1);
207 wpa_printf(MSG_DEBUG, "EAP-PSK: Flags=0x%x", hdr3->flags);
208 if (EAP_PSK_FLAGS_GET_T(hdr3->flags) != 2) {
209 wpa_printf(MSG_INFO, "EAP-PSK: Unexpected T=%d (expected 2)",
210 EAP_PSK_FLAGS_GET_T(hdr3->flags));
211 ret->methodState = METHOD_DONE;
212 ret->decision = DECISION_FAIL;
215 wpa_hexdump(MSG_DEBUG, "EAP-PSK: RAND_S", hdr3->rand_s,
217 wpa_hexdump(MSG_DEBUG, "EAP-PSK: MAC_S", hdr3->mac_s, EAP_PSK_MAC_LEN);
218 wpa_hexdump(MSG_DEBUG, "EAP-PSK: PCHANNEL", pchannel, left);
220 if (left < 4 + 16 + 1) {
221 wpa_printf(MSG_INFO, "EAP-PSK: Too short PCHANNEL data in "
222 "third message (len=%lu, expected 21)",
223 (unsigned long) left);
228 /* MAC_S = OMAC1-AES-128(AK, ID_S||RAND_P) */
229 buflen = data->id_s_len + EAP_PSK_RAND_LEN;
230 buf = os_malloc(buflen);
233 os_memcpy(buf, data->id_s, data->id_s_len);
234 os_memcpy(buf + data->id_s_len, data->rand_p, EAP_PSK_RAND_LEN);
235 if (omac1_aes_128(data->ak, buf, buflen, mac)) {
240 if (os_memcmp_const(mac, hdr3->mac_s, EAP_PSK_MAC_LEN) != 0) {
241 wpa_printf(MSG_WARNING, "EAP-PSK: Invalid MAC_S in third "
243 ret->methodState = METHOD_DONE;
244 ret->decision = DECISION_FAIL;
247 wpa_printf(MSG_DEBUG, "EAP-PSK: MAC_S verified successfully");
249 if (eap_psk_derive_keys(data->kdk, data->rand_p, data->tek,
250 data->msk, data->emsk)) {
251 ret->methodState = METHOD_DONE;
252 ret->decision = DECISION_FAIL;
255 wpa_hexdump_key(MSG_DEBUG, "EAP-PSK: TEK", data->tek, EAP_PSK_TEK_LEN);
256 wpa_hexdump_key(MSG_DEBUG, "EAP-PSK: MSK", data->msk, EAP_MSK_LEN);
257 wpa_hexdump_key(MSG_DEBUG, "EAP-PSK: EMSK", data->emsk, EAP_EMSK_LEN);
259 os_memset(nonce, 0, 12);
260 os_memcpy(nonce + 12, pchannel, 4);
270 wpa_hexdump(MSG_MSGDUMP, "EAP-PSK: PCHANNEL - nonce",
271 nonce, sizeof(nonce));
272 wpa_hexdump(MSG_MSGDUMP, "EAP-PSK: PCHANNEL - hdr",
273 wpabuf_head(reqData), 5);
274 wpa_hexdump(MSG_MSGDUMP, "EAP-PSK: PCHANNEL - cipher msg", msg, left);
276 decrypted = os_malloc(left);
277 if (decrypted == NULL) {
278 ret->methodState = METHOD_DONE;
279 ret->decision = DECISION_FAIL;
282 os_memcpy(decrypted, msg, left);
284 if (aes_128_eax_decrypt(data->tek, nonce, sizeof(nonce),
285 wpabuf_head(reqData),
286 sizeof(struct eap_hdr) + 1 +
287 sizeof(*hdr3) - EAP_PSK_MAC_LEN, decrypted,
289 wpa_printf(MSG_WARNING, "EAP-PSK: PCHANNEL decryption failed");
293 wpa_hexdump(MSG_DEBUG, "EAP-PSK: Decrypted PCHANNEL message",
297 switch (decrypted[0] >> 6) {
298 case EAP_PSK_R_FLAG_CONT:
299 wpa_printf(MSG_DEBUG, "EAP-PSK: R flag - CONT - unsupported");
302 case EAP_PSK_R_FLAG_DONE_SUCCESS:
303 wpa_printf(MSG_DEBUG, "EAP-PSK: R flag - DONE_SUCCESS");
305 case EAP_PSK_R_FLAG_DONE_FAILURE:
306 wpa_printf(MSG_DEBUG, "EAP-PSK: R flag - DONE_FAILURE");
307 wpa_printf(MSG_INFO, "EAP-PSK: Authentication server rejected "
314 if ((decrypted[0] & EAP_PSK_E_FLAG) && left > 1)
316 plen = sizeof(*hdr4) + 4 + 16 + data_len;
317 resp = eap_msg_alloc(EAP_VENDOR_IETF, EAP_TYPE_PSK, plen,
318 EAP_CODE_RESPONSE, eap_get_id(reqData));
323 hdr4 = wpabuf_put(resp, sizeof(*hdr4));
324 hdr4->flags = EAP_PSK_FLAGS_SET_T(3); /* T=3 */
325 os_memcpy(hdr4->rand_s, hdr3->rand_s, EAP_PSK_RAND_LEN);
326 rpchannel = wpabuf_put(resp, 4 + 16 + data_len);
329 inc_byte_array(nonce, sizeof(nonce));
330 os_memcpy(rpchannel, nonce + 12, 4);
332 if (decrypted[0] & EAP_PSK_E_FLAG) {
333 wpa_printf(MSG_DEBUG, "EAP-PSK: Unsupported E (Ext) flag");
335 rpchannel[4 + 16] = (EAP_PSK_R_FLAG_DONE_FAILURE << 6) |
338 /* Add empty EXT_Payload with same EXT_Type */
339 rpchannel[4 + 16 + 1] = decrypted[1];
342 rpchannel[4 + 16] = EAP_PSK_R_FLAG_DONE_FAILURE << 6;
344 rpchannel[4 + 16] = EAP_PSK_R_FLAG_DONE_SUCCESS << 6;
346 wpa_hexdump(MSG_DEBUG, "EAP-PSK: reply message (plaintext)",
347 rpchannel + 4 + 16, data_len);
348 if (aes_128_eax_encrypt(data->tek, nonce, sizeof(nonce),
350 sizeof(struct eap_hdr) + 1 + sizeof(*hdr4),
351 rpchannel + 4 + 16, data_len, rpchannel + 4)) {
356 wpa_hexdump(MSG_DEBUG, "EAP-PSK: reply message (PCHANNEL)",
357 rpchannel, 4 + 16 + data_len);
359 wpa_printf(MSG_DEBUG, "EAP-PSK: Completed %ssuccessfully",
361 data->state = PSK_DONE;
362 ret->methodState = METHOD_DONE;
363 ret->decision = failed ? DECISION_FAIL : DECISION_UNCOND_SUCC;
371 static struct wpabuf * eap_psk_process(struct eap_sm *sm, void *priv,
372 struct eap_method_ret *ret,
373 const struct wpabuf *reqData)
375 struct eap_psk_data *data = priv;
377 struct wpabuf *resp = NULL;
380 pos = eap_hdr_validate(EAP_VENDOR_IETF, EAP_TYPE_PSK, reqData, &len);
387 ret->methodState = METHOD_MAY_CONT;
388 ret->decision = DECISION_FAIL;
389 ret->allowNotifications = TRUE;
391 switch (data->state) {
393 resp = eap_psk_process_1(data, ret, reqData);
396 resp = eap_psk_process_3(data, ret, reqData);
399 wpa_printf(MSG_DEBUG, "EAP-PSK: in DONE state - ignore "
400 "unexpected message");
405 if (ret->methodState == METHOD_DONE) {
406 ret->allowNotifications = FALSE;
413 static Boolean eap_psk_isKeyAvailable(struct eap_sm *sm, void *priv)
415 struct eap_psk_data *data = priv;
416 return data->state == PSK_DONE;
420 static u8 * eap_psk_getKey(struct eap_sm *sm, void *priv, size_t *len)
422 struct eap_psk_data *data = priv;
425 if (data->state != PSK_DONE)
428 key = os_malloc(EAP_MSK_LEN);
433 os_memcpy(key, data->msk, EAP_MSK_LEN);
439 static u8 * eap_psk_get_session_id(struct eap_sm *sm, void *priv, size_t *len)
441 struct eap_psk_data *data = priv;
444 if (data->state != PSK_DONE)
447 *len = 1 + 2 * EAP_PSK_RAND_LEN;
448 id = os_malloc(*len);
452 id[0] = EAP_TYPE_PSK;
453 os_memcpy(id + 1, data->rand_p, EAP_PSK_RAND_LEN);
454 os_memcpy(id + 1 + EAP_PSK_RAND_LEN, data->rand_s, EAP_PSK_RAND_LEN);
455 wpa_hexdump(MSG_DEBUG, "EAP-PSK: Derived Session-Id", id, *len);
461 static u8 * eap_psk_get_emsk(struct eap_sm *sm, void *priv, size_t *len)
463 struct eap_psk_data *data = priv;
466 if (data->state != PSK_DONE)
469 key = os_malloc(EAP_EMSK_LEN);
474 os_memcpy(key, data->emsk, EAP_EMSK_LEN);
480 int eap_peer_psk_register(void)
482 struct eap_method *eap;
485 eap = eap_peer_method_alloc(EAP_PEER_METHOD_INTERFACE_VERSION,
486 EAP_VENDOR_IETF, EAP_TYPE_PSK, "PSK");
490 eap->init = eap_psk_init;
491 eap->deinit = eap_psk_deinit;
492 eap->process = eap_psk_process;
493 eap->isKeyAvailable = eap_psk_isKeyAvailable;
494 eap->getKey = eap_psk_getKey;
495 eap->getSessionId = eap_psk_get_session_id;
496 eap->get_emsk = eap_psk_get_emsk;
498 ret = eap_peer_method_register(eap);
500 eap_peer_method_free(eap);