1 /*
2 * EAP peer method: EAP-SAKE (RFC 4763)
3 * Copyright (c) 2006-2008, Jouni Malinen <j@w1.fi>
4 *
5 * This software may be distributed under the terms of the BSD license.
6 * See README for more details.
7 */
8
9 #include "includes.h"
10
11 #include "common.h"
12 #include "crypto/random.h"
13 #include "eap_peer/eap_i.h"
14 #include "eap_common/eap_sake_common.h"
15
16 struct eap_sake_data {
17 enum { IDENTITY, CHALLENGE, CONFIRM, SUCCESS, FAILURE } state;
18 u8 root_secret_a[EAP_SAKE_ROOT_SECRET_LEN];
19 u8 root_secret_b[EAP_SAKE_ROOT_SECRET_LEN];
20 u8 rand_s[EAP_SAKE_RAND_LEN];
21 u8 rand_p[EAP_SAKE_RAND_LEN];
22 struct {
23 u8 auth[EAP_SAKE_TEK_AUTH_LEN];
24 u8 cipher[EAP_SAKE_TEK_CIPHER_LEN];
25 } tek;
26 u8 msk[EAP_MSK_LEN];
27 u8 emsk[EAP_EMSK_LEN];
28 u8 session_id;
29 int session_id_set;
30 u8 *peerid;
31 size_t peerid_len;
32 u8 *serverid;
33 size_t serverid_len;
34 };
35
36
eap_sake_state_txt(int state)37 static const char * eap_sake_state_txt(int state)
38 {
39 switch (state) {
40 case IDENTITY:
41 return "IDENTITY";
42 case CHALLENGE:
43 return "CHALLENGE";
44 case CONFIRM:
45 return "CONFIRM";
46 case SUCCESS:
47 return "SUCCESS";
48 case FAILURE:
49 return "FAILURE";
50 default:
51 return "?";
52 }
53 }
54
55
eap_sake_state(struct eap_sake_data * data,int state)56 static void eap_sake_state(struct eap_sake_data *data, int state)
57 {
58 wpa_printf(MSG_DEBUG, "EAP-SAKE: %s -> %s",
59 eap_sake_state_txt(data->state),
60 eap_sake_state_txt(state));
61 data->state = state;
62 }
63
64
65 static void eap_sake_deinit(struct eap_sm *sm, void *priv);
66
67
eap_sake_init(struct eap_sm * sm)68 static void * eap_sake_init(struct eap_sm *sm)
69 {
70 struct eap_sake_data *data;
71 const u8 *identity, *password;
72 size_t identity_len, password_len;
73
74 password = eap_get_config_password(sm, &password_len);
75 if (!password || password_len != 2 * EAP_SAKE_ROOT_SECRET_LEN) {
76 wpa_printf(MSG_INFO, "EAP-SAKE: No key of correct length "
77 "configured");
78 return NULL;
79 }
80
81 data = os_zalloc(sizeof(*data));
82 if (data == NULL)
83 return NULL;
84 data->state = IDENTITY;
85
86 identity = eap_get_config_identity(sm, &identity_len);
87 if (identity) {
88 data->peerid = os_malloc(identity_len);
89 if (data->peerid == NULL) {
90 eap_sake_deinit(sm, data);
91 return NULL;
92 }
93 os_memcpy(data->peerid, identity, identity_len);
94 data->peerid_len = identity_len;
95 }
96
97 os_memcpy(data->root_secret_a, password, EAP_SAKE_ROOT_SECRET_LEN);
98 os_memcpy(data->root_secret_b,
99 password + EAP_SAKE_ROOT_SECRET_LEN,
100 EAP_SAKE_ROOT_SECRET_LEN);
101
102 return data;
103 }
104
105
eap_sake_deinit(struct eap_sm * sm,void * priv)106 static void eap_sake_deinit(struct eap_sm *sm, void *priv)
107 {
108 struct eap_sake_data *data = priv;
109 os_free(data->serverid);
110 os_free(data->peerid);
111 bin_clear_free(data, sizeof(*data));
112 }
113
114
eap_sake_build_msg(struct eap_sake_data * data,int id,size_t length,u8 subtype)115 static struct wpabuf * eap_sake_build_msg(struct eap_sake_data *data,
116 int id, size_t length, u8 subtype)
117 {
118 struct eap_sake_hdr *sake;
119 struct wpabuf *msg;
120 size_t plen;
121
122 plen = length + sizeof(struct eap_sake_hdr);
123
124 msg = eap_msg_alloc(EAP_VENDOR_IETF, EAP_TYPE_SAKE, plen,
125 EAP_CODE_RESPONSE, id);
126 if (msg == NULL) {
127 wpa_printf(MSG_ERROR, "EAP-SAKE: Failed to allocate memory "
128 "request");
129 return NULL;
130 }
131
132 sake = wpabuf_put(msg, sizeof(*sake));
133 sake->version = EAP_SAKE_VERSION;
134 sake->session_id = data->session_id;
135 sake->subtype = subtype;
136
137 return msg;
138 }
139
140
eap_sake_process_identity(struct eap_sm * sm,struct eap_sake_data * data,struct eap_method_ret * ret,const struct wpabuf * reqData,const u8 * payload,size_t payload_len)141 static struct wpabuf * eap_sake_process_identity(struct eap_sm *sm,
142 struct eap_sake_data *data,
143 struct eap_method_ret *ret,
144 const struct wpabuf *reqData,
145 const u8 *payload,
146 size_t payload_len)
147 {
148 struct eap_sake_parse_attr attr;
149 struct wpabuf *resp;
150
151 if (data->state != IDENTITY) {
152 ret->ignore = TRUE;
153 return NULL;
154 }
155
156 wpa_printf(MSG_DEBUG, "EAP-SAKE: Received Request/Identity");
157
158 if (eap_sake_parse_attributes(payload, payload_len, &attr))
159 return NULL;
160
161 if (!attr.perm_id_req && !attr.any_id_req) {
162 wpa_printf(MSG_INFO, "EAP-SAKE: No AT_PERM_ID_REQ or "
163 "AT_ANY_ID_REQ in Request/Identity");
164 return NULL;
165 }
166
167 wpa_printf(MSG_DEBUG, "EAP-SAKE: Sending Response/Identity");
168
169 resp = eap_sake_build_msg(data, eap_get_id(reqData),
170 2 + data->peerid_len,
171 EAP_SAKE_SUBTYPE_IDENTITY);
172 if (resp == NULL)
173 return NULL;
174
175 wpa_printf(MSG_DEBUG, "EAP-SAKE: * AT_PEERID");
176 eap_sake_add_attr(resp, EAP_SAKE_AT_PEERID,
177 data->peerid, data->peerid_len);
178
179 eap_sake_state(data, CHALLENGE);
180
181 return resp;
182 }
183
184
eap_sake_process_challenge(struct eap_sm * sm,struct eap_sake_data * data,struct eap_method_ret * ret,const struct wpabuf * reqData,const u8 * payload,size_t payload_len)185 static struct wpabuf * eap_sake_process_challenge(struct eap_sm *sm,
186 struct eap_sake_data *data,
187 struct eap_method_ret *ret,
188 const struct wpabuf *reqData,
189 const u8 *payload,
190 size_t payload_len)
191 {
192 struct eap_sake_parse_attr attr;
193 struct wpabuf *resp;
194 u8 *rpos;
195 size_t rlen;
196
197 if (data->state != IDENTITY && data->state != CHALLENGE) {
198 wpa_printf(MSG_DEBUG, "EAP-SAKE: Request/Challenge received "
199 "in unexpected state (%d)", data->state);
200 ret->ignore = TRUE;
201 return NULL;
202 }
203 if (data->state == IDENTITY)
204 eap_sake_state(data, CHALLENGE);
205
206 wpa_printf(MSG_DEBUG, "EAP-SAKE: Received Request/Challenge");
207
208 if (eap_sake_parse_attributes(payload, payload_len, &attr))
209 return NULL;
210
211 if (!attr.rand_s) {
212 wpa_printf(MSG_INFO, "EAP-SAKE: Request/Challenge did not "
213 "include AT_RAND_S");
214 return NULL;
215 }
216
217 os_memcpy(data->rand_s, attr.rand_s, EAP_SAKE_RAND_LEN);
218 wpa_hexdump(MSG_MSGDUMP, "EAP-SAKE: RAND_S (server rand)",
219 data->rand_s, EAP_SAKE_RAND_LEN);
220
221 if (random_get_bytes(data->rand_p, EAP_SAKE_RAND_LEN)) {
222 wpa_printf(MSG_ERROR, "EAP-SAKE: Failed to get random data");
223 return NULL;
224 }
225 wpa_hexdump(MSG_MSGDUMP, "EAP-SAKE: RAND_P (peer rand)",
226 data->rand_p, EAP_SAKE_RAND_LEN);
227
228 os_free(data->serverid);
229 data->serverid = NULL;
230 data->serverid_len = 0;
231 if (attr.serverid) {
232 wpa_hexdump_ascii(MSG_MSGDUMP, "EAP-SAKE: SERVERID",
233 attr.serverid, attr.serverid_len);
234 data->serverid = os_malloc(attr.serverid_len);
235 if (data->serverid == NULL)
236 return NULL;
237 os_memcpy(data->serverid, attr.serverid, attr.serverid_len);
238 data->serverid_len = attr.serverid_len;
239 }
240
241 eap_sake_derive_keys(data->root_secret_a, data->root_secret_b,
242 data->rand_s, data->rand_p,
243 (u8 *) &data->tek, data->msk, data->emsk);
244
245 wpa_printf(MSG_DEBUG, "EAP-SAKE: Sending Response/Challenge");
246
247 rlen = 2 + EAP_SAKE_RAND_LEN + 2 + EAP_SAKE_MIC_LEN;
248 if (data->peerid)
249 rlen += 2 + data->peerid_len;
250 resp = eap_sake_build_msg(data, eap_get_id(reqData), rlen,
251 EAP_SAKE_SUBTYPE_CHALLENGE);
252 if (resp == NULL)
253 return NULL;
254
255 wpa_printf(MSG_DEBUG, "EAP-SAKE: * AT_RAND_P");
256 eap_sake_add_attr(resp, EAP_SAKE_AT_RAND_P,
257 data->rand_p, EAP_SAKE_RAND_LEN);
258
259 if (data->peerid) {
260 wpa_printf(MSG_DEBUG, "EAP-SAKE: * AT_PEERID");
261 eap_sake_add_attr(resp, EAP_SAKE_AT_PEERID,
262 data->peerid, data->peerid_len);
263 }
264
265 wpa_printf(MSG_DEBUG, "EAP-SAKE: * AT_MIC_P");
266 wpabuf_put_u8(resp, EAP_SAKE_AT_MIC_P);
267 wpabuf_put_u8(resp, 2 + EAP_SAKE_MIC_LEN);
268 rpos = wpabuf_put(resp, EAP_SAKE_MIC_LEN);
269 if (eap_sake_compute_mic(data->tek.auth, data->rand_s, data->rand_p,
270 data->serverid, data->serverid_len,
271 data->peerid, data->peerid_len, 1,
272 wpabuf_head(resp), wpabuf_len(resp), rpos,
273 rpos)) {
274 wpa_printf(MSG_INFO, "EAP-SAKE: Failed to compute MIC");
275 wpabuf_free(resp);
276 return NULL;
277 }
278
279 eap_sake_state(data, CONFIRM);
280
281 return resp;
282 }
283
284
eap_sake_process_confirm(struct eap_sm * sm,struct eap_sake_data * data,struct eap_method_ret * ret,const struct wpabuf * reqData,const u8 * payload,size_t payload_len)285 static struct wpabuf * eap_sake_process_confirm(struct eap_sm *sm,
286 struct eap_sake_data *data,
287 struct eap_method_ret *ret,
288 const struct wpabuf *reqData,
289 const u8 *payload,
290 size_t payload_len)
291 {
292 struct eap_sake_parse_attr attr;
293 u8 mic_s[EAP_SAKE_MIC_LEN];
294 struct wpabuf *resp;
295 u8 *rpos;
296
297 if (data->state != CONFIRM) {
298 ret->ignore = TRUE;
299 return NULL;
300 }
301
302 wpa_printf(MSG_DEBUG, "EAP-SAKE: Received Request/Confirm");
303
304 if (eap_sake_parse_attributes(payload, payload_len, &attr))
305 return NULL;
306
307 if (!attr.mic_s) {
308 wpa_printf(MSG_INFO, "EAP-SAKE: Request/Confirm did not "
309 "include AT_MIC_S");
310 return NULL;
311 }
312
313 eap_sake_compute_mic(data->tek.auth, data->rand_s, data->rand_p,
314 data->serverid, data->serverid_len,
315 data->peerid, data->peerid_len, 0,
316 wpabuf_head(reqData), wpabuf_len(reqData),
317 attr.mic_s, mic_s);
318 if (os_memcmp_const(attr.mic_s, mic_s, EAP_SAKE_MIC_LEN) != 0) {
319 wpa_printf(MSG_INFO, "EAP-SAKE: Incorrect AT_MIC_S");
320 eap_sake_state(data, FAILURE);
321 ret->methodState = METHOD_DONE;
322 ret->decision = DECISION_FAIL;
323 ret->allowNotifications = FALSE;
324 wpa_printf(MSG_DEBUG, "EAP-SAKE: Sending "
325 "Response/Auth-Reject");
326 return eap_sake_build_msg(data, eap_get_id(reqData), 0,
327 EAP_SAKE_SUBTYPE_AUTH_REJECT);
328 }
329
330 wpa_printf(MSG_DEBUG, "EAP-SAKE: Sending Response/Confirm");
331
332 resp = eap_sake_build_msg(data, eap_get_id(reqData),
333 2 + EAP_SAKE_MIC_LEN,
334 EAP_SAKE_SUBTYPE_CONFIRM);
335 if (resp == NULL)
336 return NULL;
337
338 wpa_printf(MSG_DEBUG, "EAP-SAKE: * AT_MIC_P");
339 wpabuf_put_u8(resp, EAP_SAKE_AT_MIC_P);
340 wpabuf_put_u8(resp, 2 + EAP_SAKE_MIC_LEN);
341 rpos = wpabuf_put(resp, EAP_SAKE_MIC_LEN);
342 if (eap_sake_compute_mic(data->tek.auth, data->rand_s, data->rand_p,
343 data->serverid, data->serverid_len,
344 data->peerid, data->peerid_len, 1,
345 wpabuf_head(resp), wpabuf_len(resp), rpos,
346 rpos)) {
347 wpa_printf(MSG_INFO, "EAP-SAKE: Failed to compute MIC");
348 wpabuf_free(resp);
349 return NULL;
350 }
351
352 eap_sake_state(data, SUCCESS);
353 ret->methodState = METHOD_DONE;
354 ret->decision = DECISION_UNCOND_SUCC;
355 ret->allowNotifications = FALSE;
356
357 return resp;
358 }
359
360
eap_sake_process(struct eap_sm * sm,void * priv,struct eap_method_ret * ret,const struct wpabuf * reqData)361 static struct wpabuf * eap_sake_process(struct eap_sm *sm, void *priv,
362 struct eap_method_ret *ret,
363 const struct wpabuf *reqData)
364 {
365 struct eap_sake_data *data = priv;
366 const struct eap_sake_hdr *req;
367 struct wpabuf *resp;
368 const u8 *pos, *end;
369 size_t len;
370 u8 subtype, session_id;
371
372 pos = eap_hdr_validate(EAP_VENDOR_IETF, EAP_TYPE_SAKE, reqData, &len);
373 if (pos == NULL || len < sizeof(struct eap_sake_hdr)) {
374 ret->ignore = TRUE;
375 return NULL;
376 }
377
378 req = (const struct eap_sake_hdr *) pos;
379 end = pos + len;
380 subtype = req->subtype;
381 session_id = req->session_id;
382 pos = (const u8 *) (req + 1);
383
384 wpa_printf(MSG_DEBUG, "EAP-SAKE: Received frame: subtype %d "
385 "session_id %d", subtype, session_id);
386 wpa_hexdump(MSG_DEBUG, "EAP-SAKE: Received attributes",
387 pos, end - pos);
388
389 if (data->session_id_set && data->session_id != session_id) {
390 wpa_printf(MSG_INFO, "EAP-SAKE: Session ID mismatch (%d,%d)",
391 session_id, data->session_id);
392 ret->ignore = TRUE;
393 return NULL;
394 }
395 data->session_id = session_id;
396 data->session_id_set = 1;
397
398 ret->ignore = FALSE;
399 ret->methodState = METHOD_MAY_CONT;
400 ret->decision = DECISION_FAIL;
401 ret->allowNotifications = TRUE;
402
403 switch (subtype) {
404 case EAP_SAKE_SUBTYPE_IDENTITY:
405 resp = eap_sake_process_identity(sm, data, ret, reqData,
406 pos, end - pos);
407 break;
408 case EAP_SAKE_SUBTYPE_CHALLENGE:
409 resp = eap_sake_process_challenge(sm, data, ret, reqData,
410 pos, end - pos);
411 break;
412 case EAP_SAKE_SUBTYPE_CONFIRM:
413 resp = eap_sake_process_confirm(sm, data, ret, reqData,
414 pos, end - pos);
415 break;
416 default:
417 wpa_printf(MSG_DEBUG, "EAP-SAKE: Ignoring message with "
418 "unknown subtype %d", subtype);
419 ret->ignore = TRUE;
420 return NULL;
421 }
422
423 if (ret->methodState == METHOD_DONE)
424 ret->allowNotifications = FALSE;
425
426 return resp;
427 }
428
429
eap_sake_isKeyAvailable(struct eap_sm * sm,void * priv)430 static Boolean eap_sake_isKeyAvailable(struct eap_sm *sm, void *priv)
431 {
432 struct eap_sake_data *data = priv;
433 return data->state == SUCCESS;
434 }
435
436
eap_sake_getKey(struct eap_sm * sm,void * priv,size_t * len)437 static u8 * eap_sake_getKey(struct eap_sm *sm, void *priv, size_t *len)
438 {
439 struct eap_sake_data *data = priv;
440 u8 *key;
441
442 if (data->state != SUCCESS)
443 return NULL;
444
445 key = os_malloc(EAP_MSK_LEN);
446 if (key == NULL)
447 return NULL;
448 os_memcpy(key, data->msk, EAP_MSK_LEN);
449 *len = EAP_MSK_LEN;
450
451 return key;
452 }
453
454
eap_sake_get_session_id(struct eap_sm * sm,void * priv,size_t * len)455 static u8 * eap_sake_get_session_id(struct eap_sm *sm, void *priv, size_t *len)
456 {
457 struct eap_sake_data *data = priv;
458 u8 *id;
459
460 if (data->state != SUCCESS)
461 return NULL;
462
463 *len = 1 + 2 * EAP_SAKE_RAND_LEN;
464 id = os_malloc(*len);
465 if (id == NULL)
466 return NULL;
467
468 id[0] = EAP_TYPE_SAKE;
469 os_memcpy(id + 1, data->rand_s, EAP_SAKE_RAND_LEN);
470 os_memcpy(id + 1 + EAP_SAKE_RAND_LEN, data->rand_s, EAP_SAKE_RAND_LEN);
471 wpa_hexdump(MSG_DEBUG, "EAP-SAKE: Derived Session-Id", id, *len);
472
473 return id;
474 }
475
476
eap_sake_get_emsk(struct eap_sm * sm,void * priv,size_t * len)477 static u8 * eap_sake_get_emsk(struct eap_sm *sm, void *priv, size_t *len)
478 {
479 struct eap_sake_data *data = priv;
480 u8 *key;
481
482 if (data->state != SUCCESS)
483 return NULL;
484
485 key = os_malloc(EAP_EMSK_LEN);
486 if (key == NULL)
487 return NULL;
488 os_memcpy(key, data->emsk, EAP_EMSK_LEN);
489 *len = EAP_EMSK_LEN;
490
491 return key;
492 }
493
494
eap_peer_sake_register(void)495 int eap_peer_sake_register(void)
496 {
497 struct eap_method *eap;
498 int ret;
499
500 eap = eap_peer_method_alloc(EAP_PEER_METHOD_INTERFACE_VERSION,
501 EAP_VENDOR_IETF, EAP_TYPE_SAKE, "SAKE");
502 if (eap == NULL)
503 return -1;
504
505 eap->init = eap_sake_init;
506 eap->deinit = eap_sake_deinit;
507 eap->process = eap_sake_process;
508 eap->isKeyAvailable = eap_sake_isKeyAvailable;
509 eap->getKey = eap_sake_getKey;
510 eap->getSessionId = eap_sake_get_session_id;
511 eap->get_emsk = eap_sake_get_emsk;
512
513 ret = eap_peer_method_register(eap);
514 if (ret)
515 eap_peer_method_free(eap);
516 return ret;
517 }
518