1 /*
2 * hostapd / EAP-SAKE (RFC 4763) server
3 * Copyright (c) 2006-2007, 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_server/eap_i.h"
14 #include "eap_common/eap_sake_common.h"
15
16
17 struct eap_sake_data {
18 enum { IDENTITY, CHALLENGE, CONFIRM, SUCCESS, FAILURE } state;
19 u8 rand_s[EAP_SAKE_RAND_LEN];
20 u8 rand_p[EAP_SAKE_RAND_LEN];
21 struct {
22 u8 auth[EAP_SAKE_TEK_AUTH_LEN];
23 u8 cipher[EAP_SAKE_TEK_CIPHER_LEN];
24 } tek;
25 u8 msk[EAP_MSK_LEN];
26 u8 emsk[EAP_EMSK_LEN];
27 u8 session_id;
28 u8 *peerid;
29 size_t peerid_len;
30 };
31
32
eap_sake_state_txt(int state)33 static const char * eap_sake_state_txt(int state)
34 {
35 switch (state) {
36 case IDENTITY:
37 return "IDENTITY";
38 case CHALLENGE:
39 return "CHALLENGE";
40 case CONFIRM:
41 return "CONFIRM";
42 case SUCCESS:
43 return "SUCCESS";
44 case FAILURE:
45 return "FAILURE";
46 default:
47 return "?";
48 }
49 }
50
51
eap_sake_state(struct eap_sake_data * data,int state)52 static void eap_sake_state(struct eap_sake_data *data, int state)
53 {
54 wpa_printf(MSG_DEBUG, "EAP-SAKE: %s -> %s",
55 eap_sake_state_txt(data->state),
56 eap_sake_state_txt(state));
57 data->state = state;
58 }
59
60
eap_sake_init(struct eap_sm * sm)61 static void * eap_sake_init(struct eap_sm *sm)
62 {
63 struct eap_sake_data *data;
64
65 data = os_zalloc(sizeof(*data));
66 if (data == NULL)
67 return NULL;
68 data->state = CHALLENGE;
69
70 if (os_get_random(&data->session_id, 1)) {
71 wpa_printf(MSG_ERROR, "EAP-SAKE: Failed to get random data");
72 os_free(data);
73 return NULL;
74 }
75 wpa_printf(MSG_DEBUG, "EAP-SAKE: Initialized Session ID %d",
76 data->session_id);
77
78 return data;
79 }
80
81
eap_sake_reset(struct eap_sm * sm,void * priv)82 static void eap_sake_reset(struct eap_sm *sm, void *priv)
83 {
84 struct eap_sake_data *data = priv;
85 os_free(data->peerid);
86 bin_clear_free(data, sizeof(*data));
87 }
88
89
eap_sake_build_msg(struct eap_sake_data * data,u8 id,size_t length,u8 subtype)90 static struct wpabuf * eap_sake_build_msg(struct eap_sake_data *data,
91 u8 id, size_t length, u8 subtype)
92 {
93 struct eap_sake_hdr *sake;
94 struct wpabuf *msg;
95 size_t plen;
96
97 plen = sizeof(struct eap_sake_hdr) + length;
98
99 msg = eap_msg_alloc(EAP_VENDOR_IETF, EAP_TYPE_SAKE, plen,
100 EAP_CODE_REQUEST, id);
101 if (msg == NULL) {
102 wpa_printf(MSG_ERROR, "EAP-SAKE: Failed to allocate memory "
103 "request");
104 return NULL;
105 }
106
107 sake = wpabuf_put(msg, sizeof(*sake));
108 sake->version = EAP_SAKE_VERSION;
109 sake->session_id = data->session_id;
110 sake->subtype = subtype;
111
112 return msg;
113 }
114
115
eap_sake_build_identity(struct eap_sm * sm,struct eap_sake_data * data,u8 id)116 static struct wpabuf * eap_sake_build_identity(struct eap_sm *sm,
117 struct eap_sake_data *data,
118 u8 id)
119 {
120 struct wpabuf *msg;
121 size_t plen;
122
123 wpa_printf(MSG_DEBUG, "EAP-SAKE: Request/Identity");
124
125 plen = 4;
126 plen += 2 + sm->server_id_len;
127 msg = eap_sake_build_msg(data, id, plen, EAP_SAKE_SUBTYPE_IDENTITY);
128 if (msg == NULL) {
129 data->state = FAILURE;
130 return NULL;
131 }
132
133 wpa_printf(MSG_DEBUG, "EAP-SAKE: * AT_PERM_ID_REQ");
134 eap_sake_add_attr(msg, EAP_SAKE_AT_PERM_ID_REQ, NULL, 2);
135
136 wpa_printf(MSG_DEBUG, "EAP-SAKE: * AT_SERVERID");
137 eap_sake_add_attr(msg, EAP_SAKE_AT_SERVERID,
138 sm->server_id, sm->server_id_len);
139
140 return msg;
141 }
142
143
eap_sake_build_challenge(struct eap_sm * sm,struct eap_sake_data * data,u8 id)144 static struct wpabuf * eap_sake_build_challenge(struct eap_sm *sm,
145 struct eap_sake_data *data,
146 u8 id)
147 {
148 struct wpabuf *msg;
149 size_t plen;
150
151 wpa_printf(MSG_DEBUG, "EAP-SAKE: Request/Challenge");
152
153 if (random_get_bytes(data->rand_s, EAP_SAKE_RAND_LEN)) {
154 wpa_printf(MSG_ERROR, "EAP-SAKE: Failed to get random data");
155 data->state = FAILURE;
156 return NULL;
157 }
158 wpa_hexdump(MSG_MSGDUMP, "EAP-SAKE: RAND_S (server rand)",
159 data->rand_s, EAP_SAKE_RAND_LEN);
160
161 plen = 2 + EAP_SAKE_RAND_LEN + 2 + sm->server_id_len;
162 msg = eap_sake_build_msg(data, id, plen, EAP_SAKE_SUBTYPE_CHALLENGE);
163 if (msg == NULL) {
164 data->state = FAILURE;
165 return NULL;
166 }
167
168 wpa_printf(MSG_DEBUG, "EAP-SAKE: * AT_RAND_S");
169 eap_sake_add_attr(msg, EAP_SAKE_AT_RAND_S,
170 data->rand_s, EAP_SAKE_RAND_LEN);
171
172 wpa_printf(MSG_DEBUG, "EAP-SAKE: * AT_SERVERID");
173 eap_sake_add_attr(msg, EAP_SAKE_AT_SERVERID,
174 sm->server_id, sm->server_id_len);
175
176 return msg;
177 }
178
179
eap_sake_build_confirm(struct eap_sm * sm,struct eap_sake_data * data,u8 id)180 static struct wpabuf * eap_sake_build_confirm(struct eap_sm *sm,
181 struct eap_sake_data *data,
182 u8 id)
183 {
184 struct wpabuf *msg;
185 u8 *mic;
186
187 wpa_printf(MSG_DEBUG, "EAP-SAKE: Request/Confirm");
188
189 msg = eap_sake_build_msg(data, id, 2 + EAP_SAKE_MIC_LEN,
190 EAP_SAKE_SUBTYPE_CONFIRM);
191 if (msg == NULL) {
192 data->state = FAILURE;
193 return NULL;
194 }
195
196 wpa_printf(MSG_DEBUG, "EAP-SAKE: * AT_MIC_S");
197 wpabuf_put_u8(msg, EAP_SAKE_AT_MIC_S);
198 wpabuf_put_u8(msg, 2 + EAP_SAKE_MIC_LEN);
199 mic = wpabuf_put(msg, EAP_SAKE_MIC_LEN);
200 if (eap_sake_compute_mic(data->tek.auth, data->rand_s, data->rand_p,
201 sm->server_id, sm->server_id_len,
202 data->peerid, data->peerid_len, 0,
203 wpabuf_head(msg), wpabuf_len(msg), mic, mic))
204 {
205 wpa_printf(MSG_INFO, "EAP-SAKE: Failed to compute MIC");
206 data->state = FAILURE;
207 os_free(msg);
208 return NULL;
209 }
210
211 return msg;
212 }
213
214
eap_sake_buildReq(struct eap_sm * sm,void * priv,u8 id)215 static struct wpabuf * eap_sake_buildReq(struct eap_sm *sm, void *priv, u8 id)
216 {
217 struct eap_sake_data *data = priv;
218
219 switch (data->state) {
220 case IDENTITY:
221 return eap_sake_build_identity(sm, data, id);
222 case CHALLENGE:
223 return eap_sake_build_challenge(sm, data, id);
224 case CONFIRM:
225 return eap_sake_build_confirm(sm, data, id);
226 default:
227 wpa_printf(MSG_DEBUG, "EAP-SAKE: Unknown state %d in buildReq",
228 data->state);
229 break;
230 }
231 return NULL;
232 }
233
234
eap_sake_check(struct eap_sm * sm,void * priv,struct wpabuf * respData)235 static Boolean eap_sake_check(struct eap_sm *sm, void *priv,
236 struct wpabuf *respData)
237 {
238 struct eap_sake_data *data = priv;
239 struct eap_sake_hdr *resp;
240 size_t len;
241 u8 version, session_id, subtype;
242 const u8 *pos;
243
244 pos = eap_hdr_validate(EAP_VENDOR_IETF, EAP_TYPE_SAKE, respData, &len);
245 if (pos == NULL || len < sizeof(struct eap_sake_hdr)) {
246 wpa_printf(MSG_INFO, "EAP-SAKE: Invalid frame");
247 return TRUE;
248 }
249
250 resp = (struct eap_sake_hdr *) pos;
251 version = resp->version;
252 session_id = resp->session_id;
253 subtype = resp->subtype;
254
255 if (version != EAP_SAKE_VERSION) {
256 wpa_printf(MSG_INFO, "EAP-SAKE: Unknown version %d", version);
257 return TRUE;
258 }
259
260 if (session_id != data->session_id) {
261 wpa_printf(MSG_INFO, "EAP-SAKE: Session ID mismatch (%d,%d)",
262 session_id, data->session_id);
263 return TRUE;
264 }
265
266 wpa_printf(MSG_DEBUG, "EAP-SAKE: Received frame: subtype=%d", subtype);
267
268 if (data->state == IDENTITY && subtype == EAP_SAKE_SUBTYPE_IDENTITY)
269 return FALSE;
270
271 if (data->state == CHALLENGE && subtype == EAP_SAKE_SUBTYPE_CHALLENGE)
272 return FALSE;
273
274 if (data->state == CONFIRM && subtype == EAP_SAKE_SUBTYPE_CONFIRM)
275 return FALSE;
276
277 if (subtype == EAP_SAKE_SUBTYPE_AUTH_REJECT)
278 return FALSE;
279
280 wpa_printf(MSG_INFO, "EAP-SAKE: Unexpected subtype=%d in state=%d",
281 subtype, data->state);
282
283 return TRUE;
284 }
285
286
eap_sake_process_identity(struct eap_sm * sm,struct eap_sake_data * data,const struct wpabuf * respData,const u8 * payload,size_t payloadlen)287 static void eap_sake_process_identity(struct eap_sm *sm,
288 struct eap_sake_data *data,
289 const struct wpabuf *respData,
290 const u8 *payload, size_t payloadlen)
291 {
292 if (data->state != IDENTITY)
293 return;
294
295 wpa_printf(MSG_DEBUG, "EAP-SAKE: Received Response/Identity");
296 /* TODO: update identity and select new user data */
297 eap_sake_state(data, CHALLENGE);
298 }
299
300
eap_sake_process_challenge(struct eap_sm * sm,struct eap_sake_data * data,const struct wpabuf * respData,const u8 * payload,size_t payloadlen)301 static void eap_sake_process_challenge(struct eap_sm *sm,
302 struct eap_sake_data *data,
303 const struct wpabuf *respData,
304 const u8 *payload, size_t payloadlen)
305 {
306 struct eap_sake_parse_attr attr;
307 u8 mic_p[EAP_SAKE_MIC_LEN];
308
309 if (data->state != CHALLENGE)
310 return;
311
312 wpa_printf(MSG_DEBUG, "EAP-SAKE: Received Response/Challenge");
313
314 if (eap_sake_parse_attributes(payload, payloadlen, &attr))
315 return;
316
317 if (!attr.rand_p || !attr.mic_p) {
318 wpa_printf(MSG_INFO, "EAP-SAKE: Response/Challenge did not "
319 "include AT_RAND_P or AT_MIC_P");
320 return;
321 }
322
323 os_memcpy(data->rand_p, attr.rand_p, EAP_SAKE_RAND_LEN);
324
325 os_free(data->peerid);
326 data->peerid = NULL;
327 data->peerid_len = 0;
328 if (attr.peerid) {
329 data->peerid = os_malloc(attr.peerid_len);
330 if (data->peerid == NULL)
331 return;
332 os_memcpy(data->peerid, attr.peerid, attr.peerid_len);
333 data->peerid_len = attr.peerid_len;
334 }
335
336 if (sm->user == NULL || sm->user->password == NULL ||
337 sm->user->password_len != 2 * EAP_SAKE_ROOT_SECRET_LEN) {
338 wpa_printf(MSG_INFO, "EAP-SAKE: Plaintext password with "
339 "%d-byte key not configured",
340 2 * EAP_SAKE_ROOT_SECRET_LEN);
341 data->state = FAILURE;
342 return;
343 }
344 eap_sake_derive_keys(sm->user->password,
345 sm->user->password + EAP_SAKE_ROOT_SECRET_LEN,
346 data->rand_s, data->rand_p,
347 (u8 *) &data->tek, data->msk, data->emsk);
348
349 eap_sake_compute_mic(data->tek.auth, data->rand_s, data->rand_p,
350 sm->server_id, sm->server_id_len,
351 data->peerid, data->peerid_len, 1,
352 wpabuf_head(respData), wpabuf_len(respData),
353 attr.mic_p, mic_p);
354 if (os_memcmp_const(attr.mic_p, mic_p, EAP_SAKE_MIC_LEN) != 0) {
355 wpa_printf(MSG_INFO, "EAP-SAKE: Incorrect AT_MIC_P");
356 eap_sake_state(data, FAILURE);
357 return;
358 }
359
360 eap_sake_state(data, CONFIRM);
361 }
362
363
eap_sake_process_confirm(struct eap_sm * sm,struct eap_sake_data * data,const struct wpabuf * respData,const u8 * payload,size_t payloadlen)364 static void eap_sake_process_confirm(struct eap_sm *sm,
365 struct eap_sake_data *data,
366 const struct wpabuf *respData,
367 const u8 *payload, size_t payloadlen)
368 {
369 struct eap_sake_parse_attr attr;
370 u8 mic_p[EAP_SAKE_MIC_LEN];
371
372 if (data->state != CONFIRM)
373 return;
374
375 wpa_printf(MSG_DEBUG, "EAP-SAKE: Received Response/Confirm");
376
377 if (eap_sake_parse_attributes(payload, payloadlen, &attr))
378 return;
379
380 if (!attr.mic_p) {
381 wpa_printf(MSG_INFO, "EAP-SAKE: Response/Confirm did not "
382 "include AT_MIC_P");
383 return;
384 }
385
386 eap_sake_compute_mic(data->tek.auth, data->rand_s, data->rand_p,
387 sm->server_id, sm->server_id_len,
388 data->peerid, data->peerid_len, 1,
389 wpabuf_head(respData), wpabuf_len(respData),
390 attr.mic_p, mic_p);
391 if (os_memcmp_const(attr.mic_p, mic_p, EAP_SAKE_MIC_LEN) != 0) {
392 wpa_printf(MSG_INFO, "EAP-SAKE: Incorrect AT_MIC_P");
393 eap_sake_state(data, FAILURE);
394 } else
395 eap_sake_state(data, SUCCESS);
396 }
397
398
eap_sake_process_auth_reject(struct eap_sm * sm,struct eap_sake_data * data,const struct wpabuf * respData,const u8 * payload,size_t payloadlen)399 static void eap_sake_process_auth_reject(struct eap_sm *sm,
400 struct eap_sake_data *data,
401 const struct wpabuf *respData,
402 const u8 *payload, size_t payloadlen)
403 {
404 wpa_printf(MSG_DEBUG, "EAP-SAKE: Received Response/Auth-Reject");
405 eap_sake_state(data, FAILURE);
406 }
407
408
eap_sake_process(struct eap_sm * sm,void * priv,struct wpabuf * respData)409 static void eap_sake_process(struct eap_sm *sm, void *priv,
410 struct wpabuf *respData)
411 {
412 struct eap_sake_data *data = priv;
413 struct eap_sake_hdr *resp;
414 u8 subtype;
415 size_t len;
416 const u8 *pos, *end;
417
418 pos = eap_hdr_validate(EAP_VENDOR_IETF, EAP_TYPE_SAKE, respData, &len);
419 if (pos == NULL || len < sizeof(struct eap_sake_hdr))
420 return;
421
422 resp = (struct eap_sake_hdr *) pos;
423 end = pos + len;
424 subtype = resp->subtype;
425 pos = (u8 *) (resp + 1);
426
427 wpa_hexdump(MSG_DEBUG, "EAP-SAKE: Received attributes",
428 pos, end - pos);
429
430 switch (subtype) {
431 case EAP_SAKE_SUBTYPE_IDENTITY:
432 eap_sake_process_identity(sm, data, respData, pos, end - pos);
433 break;
434 case EAP_SAKE_SUBTYPE_CHALLENGE:
435 eap_sake_process_challenge(sm, data, respData, pos, end - pos);
436 break;
437 case EAP_SAKE_SUBTYPE_CONFIRM:
438 eap_sake_process_confirm(sm, data, respData, pos, end - pos);
439 break;
440 case EAP_SAKE_SUBTYPE_AUTH_REJECT:
441 eap_sake_process_auth_reject(sm, data, respData, pos,
442 end - pos);
443 break;
444 }
445 }
446
447
eap_sake_isDone(struct eap_sm * sm,void * priv)448 static Boolean eap_sake_isDone(struct eap_sm *sm, void *priv)
449 {
450 struct eap_sake_data *data = priv;
451 return data->state == SUCCESS || data->state == FAILURE;
452 }
453
454
eap_sake_getKey(struct eap_sm * sm,void * priv,size_t * len)455 static u8 * eap_sake_getKey(struct eap_sm *sm, void *priv, size_t *len)
456 {
457 struct eap_sake_data *data = priv;
458 u8 *key;
459
460 if (data->state != SUCCESS)
461 return NULL;
462
463 key = os_malloc(EAP_MSK_LEN);
464 if (key == NULL)
465 return NULL;
466 os_memcpy(key, data->msk, EAP_MSK_LEN);
467 *len = EAP_MSK_LEN;
468
469 return key;
470 }
471
472
eap_sake_get_emsk(struct eap_sm * sm,void * priv,size_t * len)473 static u8 * eap_sake_get_emsk(struct eap_sm *sm, void *priv, size_t *len)
474 {
475 struct eap_sake_data *data = priv;
476 u8 *key;
477
478 if (data->state != SUCCESS)
479 return NULL;
480
481 key = os_malloc(EAP_EMSK_LEN);
482 if (key == NULL)
483 return NULL;
484 os_memcpy(key, data->emsk, EAP_EMSK_LEN);
485 *len = EAP_EMSK_LEN;
486
487 return key;
488 }
489
490
eap_sake_isSuccess(struct eap_sm * sm,void * priv)491 static Boolean eap_sake_isSuccess(struct eap_sm *sm, void *priv)
492 {
493 struct eap_sake_data *data = priv;
494 return data->state == SUCCESS;
495 }
496
497
eap_sake_get_session_id(struct eap_sm * sm,void * priv,size_t * len)498 static u8 * eap_sake_get_session_id(struct eap_sm *sm, void *priv, size_t *len)
499 {
500 struct eap_sake_data *data = priv;
501 u8 *id;
502
503 if (data->state != SUCCESS)
504 return NULL;
505
506 *len = 1 + 2 * EAP_SAKE_RAND_LEN;
507 id = os_malloc(*len);
508 if (id == NULL)
509 return NULL;
510
511 id[0] = EAP_TYPE_SAKE;
512 os_memcpy(id + 1, data->rand_s, EAP_SAKE_RAND_LEN);
513 os_memcpy(id + 1 + EAP_SAKE_RAND_LEN, data->rand_s, EAP_SAKE_RAND_LEN);
514 wpa_hexdump(MSG_DEBUG, "EAP-SAKE: Derived Session-Id", id, *len);
515
516 return id;
517 }
518
519
eap_server_sake_register(void)520 int eap_server_sake_register(void)
521 {
522 struct eap_method *eap;
523
524 eap = eap_server_method_alloc(EAP_SERVER_METHOD_INTERFACE_VERSION,
525 EAP_VENDOR_IETF, EAP_TYPE_SAKE, "SAKE");
526 if (eap == NULL)
527 return -1;
528
529 eap->init = eap_sake_init;
530 eap->reset = eap_sake_reset;
531 eap->buildReq = eap_sake_buildReq;
532 eap->check = eap_sake_check;
533 eap->process = eap_sake_process;
534 eap->isDone = eap_sake_isDone;
535 eap->getKey = eap_sake_getKey;
536 eap->isSuccess = eap_sake_isSuccess;
537 eap->get_emsk = eap_sake_get_emsk;
538 eap->getSessionId = eap_sake_get_session_id;
539
540 return eap_server_method_register(eap);
541 }
542