1 /*
2 * EAP peer method: EAP-SAKE (RFC 4763)
3 * Copyright (c) 2006-2019, 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 if (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,
241 data->emsk) < 0) {
242 wpa_printf(MSG_INFO, "EAP-SAKE: Failed to derive keys");
243 return NULL;
244 }
245
246 wpa_printf(MSG_DEBUG, "EAP-SAKE: Sending Response/Challenge");
247
248 rlen = 2 + EAP_SAKE_RAND_LEN + 2 + EAP_SAKE_MIC_LEN;
249 if (data->peerid)
250 rlen += 2 + data->peerid_len;
251 resp = eap_sake_build_msg(data, id, rlen, 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,u8 id,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 u8 id,
289 const struct wpabuf *reqData,
290 const u8 *payload,
291 size_t payload_len)
292 {
293 struct eap_sake_parse_attr attr;
294 u8 mic_s[EAP_SAKE_MIC_LEN];
295 struct wpabuf *resp;
296 u8 *rpos;
297
298 if (data->state != CONFIRM) {
299 ret->ignore = true;
300 return NULL;
301 }
302
303 wpa_printf(MSG_DEBUG, "EAP-SAKE: Received Request/Confirm");
304
305 if (eap_sake_parse_attributes(payload, payload_len, &attr))
306 return NULL;
307
308 if (!attr.mic_s) {
309 wpa_printf(MSG_INFO, "EAP-SAKE: Request/Confirm did not "
310 "include AT_MIC_S");
311 return NULL;
312 }
313
314 if (eap_sake_compute_mic(data->tek.auth, data->rand_s, data->rand_p,
315 data->serverid, data->serverid_len,
316 data->peerid, data->peerid_len, 0,
317 wpabuf_head(reqData), wpabuf_len(reqData),
318 attr.mic_s, mic_s)) {
319 wpa_printf(MSG_INFO, "EAP-SAKE: Failed to compute MIC");
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 Response/Auth-Reject");
325 return eap_sake_build_msg(data, id, 0,
326 EAP_SAKE_SUBTYPE_AUTH_REJECT);
327 }
328 if (os_memcmp_const(attr.mic_s, mic_s, EAP_SAKE_MIC_LEN) != 0) {
329 wpa_printf(MSG_INFO, "EAP-SAKE: Incorrect AT_MIC_S");
330 eap_sake_state(data, FAILURE);
331 ret->methodState = METHOD_DONE;
332 ret->decision = DECISION_FAIL;
333 ret->allowNotifications = false;
334 wpa_printf(MSG_DEBUG, "EAP-SAKE: Sending "
335 "Response/Auth-Reject");
336 return eap_sake_build_msg(data, id, 0,
337 EAP_SAKE_SUBTYPE_AUTH_REJECT);
338 }
339
340 wpa_printf(MSG_DEBUG, "EAP-SAKE: Sending Response/Confirm");
341
342 resp = eap_sake_build_msg(data, id, 2 + EAP_SAKE_MIC_LEN,
343 EAP_SAKE_SUBTYPE_CONFIRM);
344 if (resp == NULL)
345 return NULL;
346
347 wpa_printf(MSG_DEBUG, "EAP-SAKE: * AT_MIC_P");
348 wpabuf_put_u8(resp, EAP_SAKE_AT_MIC_P);
349 wpabuf_put_u8(resp, 2 + EAP_SAKE_MIC_LEN);
350 rpos = wpabuf_put(resp, EAP_SAKE_MIC_LEN);
351 if (eap_sake_compute_mic(data->tek.auth, data->rand_s, data->rand_p,
352 data->serverid, data->serverid_len,
353 data->peerid, data->peerid_len, 1,
354 wpabuf_head(resp), wpabuf_len(resp), rpos,
355 rpos)) {
356 wpa_printf(MSG_INFO, "EAP-SAKE: Failed to compute MIC");
357 wpabuf_free(resp);
358 return NULL;
359 }
360
361 eap_sake_state(data, SUCCESS);
362 ret->methodState = METHOD_DONE;
363 ret->decision = DECISION_UNCOND_SUCC;
364 ret->allowNotifications = false;
365
366 return resp;
367 }
368
369
eap_sake_process(struct eap_sm * sm,void * priv,struct eap_method_ret * ret,const struct wpabuf * reqData)370 static struct wpabuf * eap_sake_process(struct eap_sm *sm, void *priv,
371 struct eap_method_ret *ret,
372 const struct wpabuf *reqData)
373 {
374 struct eap_sake_data *data = priv;
375 const struct eap_sake_hdr *req;
376 struct wpabuf *resp;
377 const u8 *pos, *end;
378 size_t len;
379 u8 subtype, session_id, id;
380
381 pos = eap_hdr_validate(EAP_VENDOR_IETF, EAP_TYPE_SAKE, reqData, &len);
382 if (pos == NULL || len < sizeof(struct eap_sake_hdr)) {
383 ret->ignore = true;
384 return NULL;
385 }
386
387 req = (const struct eap_sake_hdr *) pos;
388 end = pos + len;
389 id = eap_get_id(reqData);
390 subtype = req->subtype;
391 session_id = req->session_id;
392 pos = (const u8 *) (req + 1);
393
394 wpa_printf(MSG_DEBUG, "EAP-SAKE: Received frame: subtype %d "
395 "session_id %d", subtype, session_id);
396 wpa_hexdump(MSG_DEBUG, "EAP-SAKE: Received attributes",
397 pos, end - pos);
398
399 if (data->session_id_set && data->session_id != session_id) {
400 wpa_printf(MSG_INFO, "EAP-SAKE: Session ID mismatch (%d,%d)",
401 session_id, data->session_id);
402 ret->ignore = true;
403 return NULL;
404 }
405 data->session_id = session_id;
406 data->session_id_set = 1;
407
408 ret->ignore = false;
409 ret->methodState = METHOD_MAY_CONT;
410 ret->decision = DECISION_FAIL;
411 ret->allowNotifications = true;
412
413 switch (subtype) {
414 case EAP_SAKE_SUBTYPE_IDENTITY:
415 resp = eap_sake_process_identity(sm, data, ret, id,
416 pos, end - pos);
417 break;
418 case EAP_SAKE_SUBTYPE_CHALLENGE:
419 resp = eap_sake_process_challenge(sm, data, ret, id,
420 pos, end - pos);
421 break;
422 case EAP_SAKE_SUBTYPE_CONFIRM:
423 resp = eap_sake_process_confirm(sm, data, ret, id, reqData,
424 pos, end - pos);
425 break;
426 default:
427 wpa_printf(MSG_DEBUG, "EAP-SAKE: Ignoring message with "
428 "unknown subtype %d", subtype);
429 ret->ignore = true;
430 return NULL;
431 }
432
433 if (ret->methodState == METHOD_DONE)
434 ret->allowNotifications = false;
435
436 return resp;
437 }
438
439
eap_sake_isKeyAvailable(struct eap_sm * sm,void * priv)440 static bool eap_sake_isKeyAvailable(struct eap_sm *sm, void *priv)
441 {
442 struct eap_sake_data *data = priv;
443 return data->state == SUCCESS;
444 }
445
446
eap_sake_getKey(struct eap_sm * sm,void * priv,size_t * len)447 static u8 * eap_sake_getKey(struct eap_sm *sm, void *priv, size_t *len)
448 {
449 struct eap_sake_data *data = priv;
450 u8 *key;
451
452 if (data->state != SUCCESS)
453 return NULL;
454
455 key = os_memdup(data->msk, EAP_MSK_LEN);
456 if (key == NULL)
457 return NULL;
458 *len = EAP_MSK_LEN;
459
460 return key;
461 }
462
463
eap_sake_get_session_id(struct eap_sm * sm,void * priv,size_t * len)464 static u8 * eap_sake_get_session_id(struct eap_sm *sm, void *priv, size_t *len)
465 {
466 struct eap_sake_data *data = priv;
467 u8 *id;
468
469 if (data->state != SUCCESS)
470 return NULL;
471
472 *len = 1 + 2 * EAP_SAKE_RAND_LEN;
473 id = os_malloc(*len);
474 if (id == NULL)
475 return NULL;
476
477 id[0] = EAP_TYPE_SAKE;
478 os_memcpy(id + 1, data->rand_s, EAP_SAKE_RAND_LEN);
479 os_memcpy(id + 1 + EAP_SAKE_RAND_LEN, data->rand_s, EAP_SAKE_RAND_LEN);
480 wpa_hexdump(MSG_DEBUG, "EAP-SAKE: Derived Session-Id", id, *len);
481
482 return id;
483 }
484
485
eap_sake_get_emsk(struct eap_sm * sm,void * priv,size_t * len)486 static u8 * eap_sake_get_emsk(struct eap_sm *sm, void *priv, size_t *len)
487 {
488 struct eap_sake_data *data = priv;
489 u8 *key;
490
491 if (data->state != SUCCESS)
492 return NULL;
493
494 key = os_memdup(data->emsk, EAP_EMSK_LEN);
495 if (key == NULL)
496 return NULL;
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
