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