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,u8 id,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 u8 id,
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, id, 2 + data->peerid_len,
170 EAP_SAKE_SUBTYPE_IDENTITY);
171 if (resp == NULL)
172 return NULL;
173
174 wpa_printf(MSG_DEBUG, "EAP-SAKE: * AT_PEERID");
175 eap_sake_add_attr(resp, EAP_SAKE_AT_PEERID,
176 data->peerid, data->peerid_len);
177
178 eap_sake_state(data, CHALLENGE);
179
180 return resp;
181 }
182
183
eap_sake_process_challenge(struct eap_sm * sm,struct eap_sake_data * data,struct eap_method_ret * ret,u8 id,const u8 * payload,size_t payload_len)184 static struct wpabuf * eap_sake_process_challenge(struct eap_sm *sm,
185 struct eap_sake_data *data,
186 struct eap_method_ret *ret,
187 u8 id,
188 const u8 *payload,
189 size_t payload_len)
190 {
191 struct eap_sake_parse_attr attr;
192 struct wpabuf *resp;
193 u8 *rpos;
194 size_t rlen;
195
196 if (data->state != IDENTITY && data->state != CHALLENGE) {
197 wpa_printf(MSG_DEBUG, "EAP-SAKE: Request/Challenge received "
198 "in unexpected state (%d)", data->state);
199 ret->ignore = TRUE;
200 return NULL;
201 }
202 if (data->state == IDENTITY)
203 eap_sake_state(data, CHALLENGE);
204
205 wpa_printf(MSG_DEBUG, "EAP-SAKE: Received Request/Challenge");
206
207 if (eap_sake_parse_attributes(payload, payload_len, &attr))
208 return NULL;
209
210 if (!attr.rand_s) {
211 wpa_printf(MSG_INFO, "EAP-SAKE: Request/Challenge did not "
212 "include AT_RAND_S");
213 return NULL;
214 }
215
216 os_memcpy(data->rand_s, attr.rand_s, EAP_SAKE_RAND_LEN);
217 wpa_hexdump(MSG_MSGDUMP, "EAP-SAKE: RAND_S (server rand)",
218 data->rand_s, EAP_SAKE_RAND_LEN);
219
220 if (random_get_bytes(data->rand_p, EAP_SAKE_RAND_LEN)) {
221 wpa_printf(MSG_ERROR, "EAP-SAKE: Failed to get random data");
222 return NULL;
223 }
224 wpa_hexdump(MSG_MSGDUMP, "EAP-SAKE: RAND_P (peer rand)",
225 data->rand_p, EAP_SAKE_RAND_LEN);
226
227 os_free(data->serverid);
228 data->serverid = NULL;
229 data->serverid_len = 0;
230 if (attr.serverid) {
231 wpa_hexdump_ascii(MSG_MSGDUMP, "EAP-SAKE: SERVERID",
232 attr.serverid, attr.serverid_len);
233 data->serverid = os_malloc(attr.serverid_len);
234 if (data->serverid == NULL)
235 return NULL;
236 os_memcpy(data->serverid, attr.serverid, attr.serverid_len);
237 data->serverid_len = attr.serverid_len;
238 }
239
240 eap_sake_derive_keys(data->root_secret_a, data->root_secret_b,
241 data->rand_s, data->rand_p,
242 (u8 *) &data->tek, data->msk, data->emsk);
243
244 wpa_printf(MSG_DEBUG, "EAP-SAKE: Sending Response/Challenge");
245
246 rlen = 2 + EAP_SAKE_RAND_LEN + 2 + EAP_SAKE_MIC_LEN;
247 if (data->peerid)
248 rlen += 2 + data->peerid_len;
249 resp = eap_sake_build_msg(data, id, rlen, EAP_SAKE_SUBTYPE_CHALLENGE);
250 if (resp == NULL)
251 return NULL;
252
253 wpa_printf(MSG_DEBUG, "EAP-SAKE: * AT_RAND_P");
254 eap_sake_add_attr(resp, EAP_SAKE_AT_RAND_P,
255 data->rand_p, EAP_SAKE_RAND_LEN);
256
257 if (data->peerid) {
258 wpa_printf(MSG_DEBUG, "EAP-SAKE: * AT_PEERID");
259 eap_sake_add_attr(resp, EAP_SAKE_AT_PEERID,
260 data->peerid, data->peerid_len);
261 }
262
263 wpa_printf(MSG_DEBUG, "EAP-SAKE: * AT_MIC_P");
264 wpabuf_put_u8(resp, EAP_SAKE_AT_MIC_P);
265 wpabuf_put_u8(resp, 2 + EAP_SAKE_MIC_LEN);
266 rpos = wpabuf_put(resp, EAP_SAKE_MIC_LEN);
267 if (eap_sake_compute_mic(data->tek.auth, data->rand_s, data->rand_p,
268 data->serverid, data->serverid_len,
269 data->peerid, data->peerid_len, 1,
270 wpabuf_head(resp), wpabuf_len(resp), rpos,
271 rpos)) {
272 wpa_printf(MSG_INFO, "EAP-SAKE: Failed to compute MIC");
273 wpabuf_free(resp);
274 return NULL;
275 }
276
277 eap_sake_state(data, CONFIRM);
278
279 return resp;
280 }
281
282
eap_sake_process_confirm(struct eap_sm * sm,struct eap_sake_data * data,struct eap_method_ret * ret,u8 id,const struct wpabuf * reqData,const u8 * payload,size_t payload_len)283 static struct wpabuf * eap_sake_process_confirm(struct eap_sm *sm,
284 struct eap_sake_data *data,
285 struct eap_method_ret *ret,
286 u8 id,
287 const struct wpabuf *reqData,
288 const u8 *payload,
289 size_t payload_len)
290 {
291 struct eap_sake_parse_attr attr;
292 u8 mic_s[EAP_SAKE_MIC_LEN];
293 struct wpabuf *resp;
294 u8 *rpos;
295
296 if (data->state != CONFIRM) {
297 ret->ignore = TRUE;
298 return NULL;
299 }
300
301 wpa_printf(MSG_DEBUG, "EAP-SAKE: Received Request/Confirm");
302
303 if (eap_sake_parse_attributes(payload, payload_len, &attr))
304 return NULL;
305
306 if (!attr.mic_s) {
307 wpa_printf(MSG_INFO, "EAP-SAKE: Request/Confirm did not "
308 "include AT_MIC_S");
309 return NULL;
310 }
311
312 if (eap_sake_compute_mic(data->tek.auth, data->rand_s, data->rand_p,
313 data->serverid, data->serverid_len,
314 data->peerid, data->peerid_len, 0,
315 wpabuf_head(reqData), wpabuf_len(reqData),
316 attr.mic_s, mic_s)) {
317 wpa_printf(MSG_INFO, "EAP-SAKE: Failed to compute MIC");
318 eap_sake_state(data, FAILURE);
319 ret->methodState = METHOD_DONE;
320 ret->decision = DECISION_FAIL;
321 ret->allowNotifications = FALSE;
322 wpa_printf(MSG_DEBUG, "EAP-SAKE: Sending Response/Auth-Reject");
323 return eap_sake_build_msg(data, id, 0,
324 EAP_SAKE_SUBTYPE_AUTH_REJECT);
325 }
326 if (os_memcmp_const(attr.mic_s, mic_s, EAP_SAKE_MIC_LEN) != 0) {
327 wpa_printf(MSG_INFO, "EAP-SAKE: Incorrect AT_MIC_S");
328 eap_sake_state(data, FAILURE);
329 ret->methodState = METHOD_DONE;
330 ret->decision = DECISION_FAIL;
331 ret->allowNotifications = FALSE;
332 wpa_printf(MSG_DEBUG, "EAP-SAKE: Sending "
333 "Response/Auth-Reject");
334 return eap_sake_build_msg(data, id, 0,
335 EAP_SAKE_SUBTYPE_AUTH_REJECT);
336 }
337
338 wpa_printf(MSG_DEBUG, "EAP-SAKE: Sending Response/Confirm");
339
340 resp = eap_sake_build_msg(data, id, 2 + EAP_SAKE_MIC_LEN,
341 EAP_SAKE_SUBTYPE_CONFIRM);
342 if (resp == NULL)
343 return NULL;
344
345 wpa_printf(MSG_DEBUG, "EAP-SAKE: * AT_MIC_P");
346 wpabuf_put_u8(resp, EAP_SAKE_AT_MIC_P);
347 wpabuf_put_u8(resp, 2 + EAP_SAKE_MIC_LEN);
348 rpos = wpabuf_put(resp, EAP_SAKE_MIC_LEN);
349 if (eap_sake_compute_mic(data->tek.auth, data->rand_s, data->rand_p,
350 data->serverid, data->serverid_len,
351 data->peerid, data->peerid_len, 1,
352 wpabuf_head(resp), wpabuf_len(resp), rpos,
353 rpos)) {
354 wpa_printf(MSG_INFO, "EAP-SAKE: Failed to compute MIC");
355 wpabuf_free(resp);
356 return NULL;
357 }
358
359 eap_sake_state(data, SUCCESS);
360 ret->methodState = METHOD_DONE;
361 ret->decision = DECISION_UNCOND_SUCC;
362 ret->allowNotifications = FALSE;
363
364 return resp;
365 }
366
367
eap_sake_process(struct eap_sm * sm,void * priv,struct eap_method_ret * ret,const struct wpabuf * reqData)368 static struct wpabuf * eap_sake_process(struct eap_sm *sm, void *priv,
369 struct eap_method_ret *ret,
370 const struct wpabuf *reqData)
371 {
372 struct eap_sake_data *data = priv;
373 const struct eap_sake_hdr *req;
374 struct wpabuf *resp;
375 const u8 *pos, *end;
376 size_t len;
377 u8 subtype, session_id, id;
378
379 pos = eap_hdr_validate(EAP_VENDOR_IETF, EAP_TYPE_SAKE, reqData, &len);
380 if (pos == NULL || len < sizeof(struct eap_sake_hdr)) {
381 ret->ignore = TRUE;
382 return NULL;
383 }
384
385 req = (const struct eap_sake_hdr *) pos;
386 end = pos + len;
387 id = eap_get_id(reqData);
388 subtype = req->subtype;
389 session_id = req->session_id;
390 pos = (const u8 *) (req + 1);
391
392 wpa_printf(MSG_DEBUG, "EAP-SAKE: Received frame: subtype %d "
393 "session_id %d", subtype, session_id);
394 wpa_hexdump(MSG_DEBUG, "EAP-SAKE: Received attributes",
395 pos, end - pos);
396
397 if (data->session_id_set && data->session_id != session_id) {
398 wpa_printf(MSG_INFO, "EAP-SAKE: Session ID mismatch (%d,%d)",
399 session_id, data->session_id);
400 ret->ignore = TRUE;
401 return NULL;
402 }
403 data->session_id = session_id;
404 data->session_id_set = 1;
405
406 ret->ignore = FALSE;
407 ret->methodState = METHOD_MAY_CONT;
408 ret->decision = DECISION_FAIL;
409 ret->allowNotifications = TRUE;
410
411 switch (subtype) {
412 case EAP_SAKE_SUBTYPE_IDENTITY:
413 resp = eap_sake_process_identity(sm, data, ret, id,
414 pos, end - pos);
415 break;
416 case EAP_SAKE_SUBTYPE_CHALLENGE:
417 resp = eap_sake_process_challenge(sm, data, ret, id,
418 pos, end - pos);
419 break;
420 case EAP_SAKE_SUBTYPE_CONFIRM:
421 resp = eap_sake_process_confirm(sm, data, ret, id, reqData,
422 pos, end - pos);
423 break;
424 default:
425 wpa_printf(MSG_DEBUG, "EAP-SAKE: Ignoring message with "
426 "unknown subtype %d", subtype);
427 ret->ignore = TRUE;
428 return NULL;
429 }
430
431 if (ret->methodState == METHOD_DONE)
432 ret->allowNotifications = FALSE;
433
434 return resp;
435 }
436
437
eap_sake_isKeyAvailable(struct eap_sm * sm,void * priv)438 static Boolean eap_sake_isKeyAvailable(struct eap_sm *sm, void *priv)
439 {
440 struct eap_sake_data *data = priv;
441 return data->state == SUCCESS;
442 }
443
444
eap_sake_getKey(struct eap_sm * sm,void * priv,size_t * len)445 static u8 * eap_sake_getKey(struct eap_sm *sm, void *priv, size_t *len)
446 {
447 struct eap_sake_data *data = priv;
448 u8 *key;
449
450 if (data->state != SUCCESS)
451 return NULL;
452
453 key = os_malloc(EAP_MSK_LEN);
454 if (key == NULL)
455 return NULL;
456 os_memcpy(key, data->msk, EAP_MSK_LEN);
457 *len = EAP_MSK_LEN;
458
459 return key;
460 }
461
462
eap_sake_get_session_id(struct eap_sm * sm,void * priv,size_t * len)463 static u8 * eap_sake_get_session_id(struct eap_sm *sm, void *priv, size_t *len)
464 {
465 struct eap_sake_data *data = priv;
466 u8 *id;
467
468 if (data->state != SUCCESS)
469 return NULL;
470
471 *len = 1 + 2 * EAP_SAKE_RAND_LEN;
472 id = os_malloc(*len);
473 if (id == NULL)
474 return NULL;
475
476 id[0] = EAP_TYPE_SAKE;
477 os_memcpy(id + 1, data->rand_s, EAP_SAKE_RAND_LEN);
478 os_memcpy(id + 1 + EAP_SAKE_RAND_LEN, data->rand_s, EAP_SAKE_RAND_LEN);
479 wpa_hexdump(MSG_DEBUG, "EAP-SAKE: Derived Session-Id", id, *len);
480
481 return id;
482 }
483
484
eap_sake_get_emsk(struct eap_sm * sm,void * priv,size_t * len)485 static u8 * eap_sake_get_emsk(struct eap_sm *sm, void *priv, size_t *len)
486 {
487 struct eap_sake_data *data = priv;
488 u8 *key;
489
490 if (data->state != SUCCESS)
491 return NULL;
492
493 key = os_malloc(EAP_EMSK_LEN);
494 if (key == NULL)
495 return NULL;
496 os_memcpy(key, data->emsk, EAP_EMSK_LEN);
497 *len = EAP_EMSK_LEN;
498
499 return key;
500 }
501
502
eap_peer_sake_register(void)503 int eap_peer_sake_register(void)
504 {
505 struct eap_method *eap;
506
507 eap = eap_peer_method_alloc(EAP_PEER_METHOD_INTERFACE_VERSION,
508 EAP_VENDOR_IETF, EAP_TYPE_SAKE, "SAKE");
509 if (eap == NULL)
510 return -1;
511
512 eap->init = eap_sake_init;
513 eap->deinit = eap_sake_deinit;
514 eap->process = eap_sake_process;
515 eap->isKeyAvailable = eap_sake_isKeyAvailable;
516 eap->getKey = eap_sake_getKey;
517 eap->getSessionId = eap_sake_get_session_id;
518 eap->get_emsk = eap_sake_get_emsk;
519
520 return eap_peer_method_register(eap);
521 }
522