1 /*
2 * hostapd / EAP-PAX (RFC 4746) server
3 * Copyright (c) 2005-2007, 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_pax_common.h"
15
16 /*
17 * Note: only PAX_STD subprotocol is currently supported
18 *
19 * TODO: Add support with PAX_SEC with the mandatory to implement ciphersuite
20 * (HMAC_SHA1_128, IANA DH Group 14 (2048 bits), RSA-PKCS1-V1_5) and
21 * recommended ciphersuite (HMAC_SHA256_128, IANA DH Group 15 (3072 bits),
22 * RSAES-OAEP).
23 */
24
25 struct eap_pax_data {
26 enum { PAX_STD_1, PAX_STD_3, SUCCESS, FAILURE } state;
27 u8 mac_id;
28 union {
29 u8 e[2 * EAP_PAX_RAND_LEN];
30 struct {
31 u8 x[EAP_PAX_RAND_LEN]; /* server rand */
32 u8 y[EAP_PAX_RAND_LEN]; /* client rand */
33 } r;
34 } rand;
35 u8 ak[EAP_PAX_AK_LEN];
36 u8 mk[EAP_PAX_MK_LEN];
37 u8 ck[EAP_PAX_CK_LEN];
38 u8 ick[EAP_PAX_ICK_LEN];
39 int keys_set;
40 char *cid;
41 size_t cid_len;
42 };
43
44
eap_pax_init(struct eap_sm * sm)45 static void * eap_pax_init(struct eap_sm *sm)
46 {
47 struct eap_pax_data *data;
48
49 data = os_zalloc(sizeof(*data));
50 if (data == NULL)
51 return NULL;
52 data->state = PAX_STD_1;
53 /*
54 * TODO: make this configurable once EAP_PAX_HMAC_SHA256_128 is
55 * supported
56 */
57 data->mac_id = EAP_PAX_MAC_HMAC_SHA1_128;
58
59 return data;
60 }
61
62
eap_pax_reset(struct eap_sm * sm,void * priv)63 static void eap_pax_reset(struct eap_sm *sm, void *priv)
64 {
65 struct eap_pax_data *data = priv;
66 os_free(data->cid);
67 bin_clear_free(data, sizeof(*data));
68 }
69
70
eap_pax_build_std_1(struct eap_sm * sm,struct eap_pax_data * data,u8 id)71 static struct wpabuf * eap_pax_build_std_1(struct eap_sm *sm,
72 struct eap_pax_data *data, u8 id)
73 {
74 struct wpabuf *req;
75 struct eap_pax_hdr *pax;
76 u8 *pos;
77
78 wpa_printf(MSG_DEBUG, "EAP-PAX: PAX_STD-1 (sending)");
79
80 if (random_get_bytes(data->rand.r.x, EAP_PAX_RAND_LEN)) {
81 wpa_printf(MSG_ERROR, "EAP-PAX: Failed to get random data");
82 data->state = FAILURE;
83 return NULL;
84 }
85
86 req = eap_msg_alloc(EAP_VENDOR_IETF, EAP_TYPE_PAX,
87 sizeof(*pax) + 2 + EAP_PAX_RAND_LEN +
88 EAP_PAX_ICV_LEN, EAP_CODE_REQUEST, id);
89 if (req == NULL) {
90 wpa_printf(MSG_ERROR, "EAP-PAX: Failed to allocate memory "
91 "request");
92 data->state = FAILURE;
93 return NULL;
94 }
95
96 pax = wpabuf_put(req, sizeof(*pax));
97 pax->op_code = EAP_PAX_OP_STD_1;
98 pax->flags = 0;
99 pax->mac_id = data->mac_id;
100 pax->dh_group_id = EAP_PAX_DH_GROUP_NONE;
101 pax->public_key_id = EAP_PAX_PUBLIC_KEY_NONE;
102
103 wpabuf_put_be16(req, EAP_PAX_RAND_LEN);
104 wpabuf_put_data(req, data->rand.r.x, EAP_PAX_RAND_LEN);
105 wpa_hexdump(MSG_MSGDUMP, "EAP-PAX: A = X (server rand)",
106 data->rand.r.x, EAP_PAX_RAND_LEN);
107
108 pos = wpabuf_put(req, EAP_PAX_MAC_LEN);
109 eap_pax_mac(data->mac_id, (u8 *) "", 0,
110 wpabuf_mhead(req), wpabuf_len(req) - EAP_PAX_ICV_LEN,
111 NULL, 0, NULL, 0, pos);
112 wpa_hexdump(MSG_MSGDUMP, "EAP-PAX: ICV", pos, EAP_PAX_ICV_LEN);
113
114 return req;
115 }
116
117
eap_pax_build_std_3(struct eap_sm * sm,struct eap_pax_data * data,u8 id)118 static struct wpabuf * eap_pax_build_std_3(struct eap_sm *sm,
119 struct eap_pax_data *data, u8 id)
120 {
121 struct wpabuf *req;
122 struct eap_pax_hdr *pax;
123 u8 *pos;
124
125 wpa_printf(MSG_DEBUG, "EAP-PAX: PAX_STD-3 (sending)");
126
127 req = eap_msg_alloc(EAP_VENDOR_IETF, EAP_TYPE_PAX,
128 sizeof(*pax) + 2 + EAP_PAX_MAC_LEN +
129 EAP_PAX_ICV_LEN, EAP_CODE_REQUEST, id);
130 if (req == NULL) {
131 wpa_printf(MSG_ERROR, "EAP-PAX: Failed to allocate memory "
132 "request");
133 data->state = FAILURE;
134 return NULL;
135 }
136
137 pax = wpabuf_put(req, sizeof(*pax));
138 pax->op_code = EAP_PAX_OP_STD_3;
139 pax->flags = 0;
140 pax->mac_id = data->mac_id;
141 pax->dh_group_id = EAP_PAX_DH_GROUP_NONE;
142 pax->public_key_id = EAP_PAX_PUBLIC_KEY_NONE;
143
144 wpabuf_put_be16(req, EAP_PAX_MAC_LEN);
145 pos = wpabuf_put(req, EAP_PAX_MAC_LEN);
146 eap_pax_mac(data->mac_id, data->ck, EAP_PAX_CK_LEN,
147 data->rand.r.y, EAP_PAX_RAND_LEN,
148 (u8 *) data->cid, data->cid_len, NULL, 0, pos);
149 wpa_hexdump(MSG_MSGDUMP, "EAP-PAX: MAC_CK(B, CID)",
150 pos, EAP_PAX_MAC_LEN);
151 pos += EAP_PAX_MAC_LEN;
152
153 /* Optional ADE could be added here, if needed */
154
155 pos = wpabuf_put(req, EAP_PAX_MAC_LEN);
156 eap_pax_mac(data->mac_id, data->ick, EAP_PAX_ICK_LEN,
157 wpabuf_mhead(req), wpabuf_len(req) - EAP_PAX_ICV_LEN,
158 NULL, 0, NULL, 0, pos);
159 wpa_hexdump(MSG_MSGDUMP, "EAP-PAX: ICV", pos, EAP_PAX_ICV_LEN);
160
161 return req;
162 }
163
164
eap_pax_buildReq(struct eap_sm * sm,void * priv,u8 id)165 static struct wpabuf * eap_pax_buildReq(struct eap_sm *sm, void *priv, u8 id)
166 {
167 struct eap_pax_data *data = priv;
168
169 switch (data->state) {
170 case PAX_STD_1:
171 return eap_pax_build_std_1(sm, data, id);
172 case PAX_STD_3:
173 return eap_pax_build_std_3(sm, data, id);
174 default:
175 wpa_printf(MSG_DEBUG, "EAP-PAX: Unknown state %d in buildReq",
176 data->state);
177 break;
178 }
179 return NULL;
180 }
181
182
eap_pax_check(struct eap_sm * sm,void * priv,struct wpabuf * respData)183 static Boolean eap_pax_check(struct eap_sm *sm, void *priv,
184 struct wpabuf *respData)
185 {
186 struct eap_pax_data *data = priv;
187 struct eap_pax_hdr *resp;
188 const u8 *pos;
189 size_t len, mlen;
190 u8 icvbuf[EAP_PAX_ICV_LEN], *icv;
191
192 pos = eap_hdr_validate(EAP_VENDOR_IETF, EAP_TYPE_PAX, respData, &len);
193 if (pos == NULL || len < sizeof(*resp)) {
194 wpa_printf(MSG_INFO, "EAP-PAX: Invalid frame");
195 return TRUE;
196 }
197
198 mlen = sizeof(struct eap_hdr) + 1 + len;
199 resp = (struct eap_pax_hdr *) pos;
200
201 wpa_printf(MSG_DEBUG, "EAP-PAX: received frame: op_code 0x%x "
202 "flags 0x%x mac_id 0x%x dh_group_id 0x%x "
203 "public_key_id 0x%x",
204 resp->op_code, resp->flags, resp->mac_id, resp->dh_group_id,
205 resp->public_key_id);
206 wpa_hexdump(MSG_MSGDUMP, "EAP-PAX: received payload",
207 (u8 *) (resp + 1), len - sizeof(*resp) - EAP_PAX_ICV_LEN);
208
209 if (data->state == PAX_STD_1 &&
210 resp->op_code != EAP_PAX_OP_STD_2) {
211 wpa_printf(MSG_DEBUG, "EAP-PAX: Expected PAX_STD-2 - "
212 "ignore op %d", resp->op_code);
213 return TRUE;
214 }
215
216 if (data->state == PAX_STD_3 &&
217 resp->op_code != EAP_PAX_OP_ACK) {
218 wpa_printf(MSG_DEBUG, "EAP-PAX: Expected PAX-ACK - "
219 "ignore op %d", resp->op_code);
220 return TRUE;
221 }
222
223 if (resp->op_code != EAP_PAX_OP_STD_2 &&
224 resp->op_code != EAP_PAX_OP_ACK) {
225 wpa_printf(MSG_DEBUG, "EAP-PAX: Unknown op_code 0x%x",
226 resp->op_code);
227 }
228
229 if (data->mac_id != resp->mac_id) {
230 wpa_printf(MSG_DEBUG, "EAP-PAX: Expected MAC ID 0x%x, "
231 "received 0x%x", data->mac_id, resp->mac_id);
232 return TRUE;
233 }
234
235 if (resp->dh_group_id != EAP_PAX_DH_GROUP_NONE) {
236 wpa_printf(MSG_INFO, "EAP-PAX: Expected DH Group ID 0x%x, "
237 "received 0x%x", EAP_PAX_DH_GROUP_NONE,
238 resp->dh_group_id);
239 return TRUE;
240 }
241
242 if (resp->public_key_id != EAP_PAX_PUBLIC_KEY_NONE) {
243 wpa_printf(MSG_INFO, "EAP-PAX: Expected Public Key ID 0x%x, "
244 "received 0x%x", EAP_PAX_PUBLIC_KEY_NONE,
245 resp->public_key_id);
246 return TRUE;
247 }
248
249 if (resp->flags & EAP_PAX_FLAGS_MF) {
250 /* TODO: add support for reassembling fragments */
251 wpa_printf(MSG_INFO, "EAP-PAX: fragmentation not supported");
252 return TRUE;
253 }
254
255 if (resp->flags & EAP_PAX_FLAGS_CE) {
256 wpa_printf(MSG_INFO, "EAP-PAX: Unexpected CE flag");
257 return TRUE;
258 }
259
260 if (data->keys_set) {
261 if (len - sizeof(*resp) < EAP_PAX_ICV_LEN) {
262 wpa_printf(MSG_INFO, "EAP-PAX: No ICV in the packet");
263 return TRUE;
264 }
265 icv = wpabuf_mhead_u8(respData) + mlen - EAP_PAX_ICV_LEN;
266 wpa_hexdump(MSG_MSGDUMP, "EAP-PAX: ICV", icv, EAP_PAX_ICV_LEN);
267 eap_pax_mac(data->mac_id, data->ick, EAP_PAX_ICK_LEN,
268 wpabuf_mhead(respData),
269 wpabuf_len(respData) - EAP_PAX_ICV_LEN,
270 NULL, 0, NULL, 0, icvbuf);
271 if (os_memcmp_const(icvbuf, icv, EAP_PAX_ICV_LEN) != 0) {
272 wpa_printf(MSG_INFO, "EAP-PAX: Invalid ICV");
273 wpa_hexdump(MSG_MSGDUMP, "EAP-PAX: Expected ICV",
274 icvbuf, EAP_PAX_ICV_LEN);
275 return TRUE;
276 }
277 }
278
279 return FALSE;
280 }
281
282
eap_pax_process_std_2(struct eap_sm * sm,struct eap_pax_data * data,struct wpabuf * respData)283 static void eap_pax_process_std_2(struct eap_sm *sm,
284 struct eap_pax_data *data,
285 struct wpabuf *respData)
286 {
287 struct eap_pax_hdr *resp;
288 u8 mac[EAP_PAX_MAC_LEN], icvbuf[EAP_PAX_ICV_LEN];
289 const u8 *pos;
290 size_t len, left;
291 int i;
292
293 if (data->state != PAX_STD_1)
294 return;
295
296 wpa_printf(MSG_DEBUG, "EAP-PAX: Received PAX_STD-2");
297
298 pos = eap_hdr_validate(EAP_VENDOR_IETF, EAP_TYPE_PAX, respData, &len);
299 if (pos == NULL || len < sizeof(*resp) + EAP_PAX_ICV_LEN)
300 return;
301
302 resp = (struct eap_pax_hdr *) pos;
303 pos = (u8 *) (resp + 1);
304 left = len - sizeof(*resp);
305
306 if (left < 2 + EAP_PAX_RAND_LEN ||
307 WPA_GET_BE16(pos) != EAP_PAX_RAND_LEN) {
308 wpa_printf(MSG_INFO, "EAP-PAX: Too short PAX_STD-2 (B)");
309 return;
310 }
311 pos += 2;
312 left -= 2;
313 os_memcpy(data->rand.r.y, pos, EAP_PAX_RAND_LEN);
314 wpa_hexdump(MSG_MSGDUMP, "EAP-PAX: Y (client rand)",
315 data->rand.r.y, EAP_PAX_RAND_LEN);
316 pos += EAP_PAX_RAND_LEN;
317 left -= EAP_PAX_RAND_LEN;
318
319 if (left < 2 || (size_t) 2 + WPA_GET_BE16(pos) > left) {
320 wpa_printf(MSG_INFO, "EAP-PAX: Too short PAX_STD-2 (CID)");
321 return;
322 }
323 data->cid_len = WPA_GET_BE16(pos);
324 os_free(data->cid);
325 data->cid = os_malloc(data->cid_len);
326 if (data->cid == NULL) {
327 wpa_printf(MSG_INFO, "EAP-PAX: Failed to allocate memory for "
328 "CID");
329 return;
330 }
331 os_memcpy(data->cid, pos + 2, data->cid_len);
332 pos += 2 + data->cid_len;
333 left -= 2 + data->cid_len;
334 wpa_hexdump_ascii(MSG_MSGDUMP, "EAP-PAX: CID",
335 (u8 *) data->cid, data->cid_len);
336
337 if (left < 2 + EAP_PAX_MAC_LEN ||
338 WPA_GET_BE16(pos) != EAP_PAX_MAC_LEN) {
339 wpa_printf(MSG_INFO, "EAP-PAX: Too short PAX_STD-2 (MAC_CK)");
340 return;
341 }
342 pos += 2;
343 left -= 2;
344 wpa_hexdump(MSG_MSGDUMP, "EAP-PAX: MAC_CK(A, B, CID)",
345 pos, EAP_PAX_MAC_LEN);
346
347 if (eap_user_get(sm, (u8 *) data->cid, data->cid_len, 0) < 0) {
348 wpa_hexdump_ascii(MSG_DEBUG, "EAP-PAX: unknown CID",
349 (u8 *) data->cid, data->cid_len);
350 data->state = FAILURE;
351 return;
352 }
353
354 for (i = 0;
355 i < EAP_MAX_METHODS &&
356 (sm->user->methods[i].vendor != EAP_VENDOR_IETF ||
357 sm->user->methods[i].method != EAP_TYPE_NONE);
358 i++) {
359 if (sm->user->methods[i].vendor == EAP_VENDOR_IETF &&
360 sm->user->methods[i].method == EAP_TYPE_PAX)
361 break;
362 }
363
364 if (i >= EAP_MAX_METHODS ||
365 sm->user->methods[i].vendor != EAP_VENDOR_IETF ||
366 sm->user->methods[i].method != EAP_TYPE_PAX) {
367 wpa_hexdump_ascii(MSG_DEBUG,
368 "EAP-PAX: EAP-PAX not enabled for CID",
369 (u8 *) data->cid, data->cid_len);
370 data->state = FAILURE;
371 return;
372 }
373
374 if (sm->user->password == NULL ||
375 sm->user->password_len != EAP_PAX_AK_LEN) {
376 wpa_hexdump_ascii(MSG_DEBUG, "EAP-PAX: invalid password in "
377 "user database for CID",
378 (u8 *) data->cid, data->cid_len);
379 data->state = FAILURE;
380 return;
381 }
382 os_memcpy(data->ak, sm->user->password, EAP_PAX_AK_LEN);
383
384 if (eap_pax_initial_key_derivation(data->mac_id, data->ak,
385 data->rand.e, data->mk, data->ck,
386 data->ick) < 0) {
387 wpa_printf(MSG_INFO, "EAP-PAX: Failed to complete initial "
388 "key derivation");
389 data->state = FAILURE;
390 return;
391 }
392 data->keys_set = 1;
393
394 eap_pax_mac(data->mac_id, data->ck, EAP_PAX_CK_LEN,
395 data->rand.r.x, EAP_PAX_RAND_LEN,
396 data->rand.r.y, EAP_PAX_RAND_LEN,
397 (u8 *) data->cid, data->cid_len, mac);
398 if (os_memcmp_const(mac, pos, EAP_PAX_MAC_LEN) != 0) {
399 wpa_printf(MSG_INFO, "EAP-PAX: Invalid MAC_CK(A, B, CID) in "
400 "PAX_STD-2");
401 wpa_hexdump(MSG_MSGDUMP, "EAP-PAX: Expected MAC_CK(A, B, CID)",
402 mac, EAP_PAX_MAC_LEN);
403 data->state = FAILURE;
404 return;
405 }
406
407 pos += EAP_PAX_MAC_LEN;
408 left -= EAP_PAX_MAC_LEN;
409
410 if (left < EAP_PAX_ICV_LEN) {
411 wpa_printf(MSG_INFO, "EAP-PAX: Too short ICV (%lu) in "
412 "PAX_STD-2", (unsigned long) left);
413 return;
414 }
415 wpa_hexdump(MSG_MSGDUMP, "EAP-PAX: ICV", pos, EAP_PAX_ICV_LEN);
416 eap_pax_mac(data->mac_id, data->ick, EAP_PAX_ICK_LEN,
417 wpabuf_head(respData),
418 wpabuf_len(respData) - EAP_PAX_ICV_LEN, NULL, 0, NULL, 0,
419 icvbuf);
420 if (os_memcmp_const(icvbuf, pos, EAP_PAX_ICV_LEN) != 0) {
421 wpa_printf(MSG_INFO, "EAP-PAX: Invalid ICV in PAX_STD-2");
422 wpa_hexdump(MSG_MSGDUMP, "EAP-PAX: Expected ICV",
423 icvbuf, EAP_PAX_ICV_LEN);
424 return;
425 }
426 pos += EAP_PAX_ICV_LEN;
427 left -= EAP_PAX_ICV_LEN;
428
429 if (left > 0) {
430 wpa_hexdump(MSG_MSGDUMP, "EAP-PAX: ignored extra payload",
431 pos, left);
432 }
433
434 data->state = PAX_STD_3;
435 }
436
437
eap_pax_process_ack(struct eap_sm * sm,struct eap_pax_data * data,struct wpabuf * respData)438 static void eap_pax_process_ack(struct eap_sm *sm,
439 struct eap_pax_data *data,
440 struct wpabuf *respData)
441 {
442 if (data->state != PAX_STD_3)
443 return;
444
445 wpa_printf(MSG_DEBUG, "EAP-PAX: Received PAX-ACK - authentication "
446 "completed successfully");
447 data->state = SUCCESS;
448 }
449
450
eap_pax_process(struct eap_sm * sm,void * priv,struct wpabuf * respData)451 static void eap_pax_process(struct eap_sm *sm, void *priv,
452 struct wpabuf *respData)
453 {
454 struct eap_pax_data *data = priv;
455 struct eap_pax_hdr *resp;
456 const u8 *pos;
457 size_t len;
458
459 if (sm->user == NULL || sm->user->password == NULL) {
460 wpa_printf(MSG_INFO, "EAP-PAX: Plaintext password not "
461 "configured");
462 data->state = FAILURE;
463 return;
464 }
465
466 pos = eap_hdr_validate(EAP_VENDOR_IETF, EAP_TYPE_PAX, respData, &len);
467 if (pos == NULL || len < sizeof(*resp))
468 return;
469
470 resp = (struct eap_pax_hdr *) pos;
471
472 switch (resp->op_code) {
473 case EAP_PAX_OP_STD_2:
474 eap_pax_process_std_2(sm, data, respData);
475 break;
476 case EAP_PAX_OP_ACK:
477 eap_pax_process_ack(sm, data, respData);
478 break;
479 }
480 }
481
482
eap_pax_isDone(struct eap_sm * sm,void * priv)483 static Boolean eap_pax_isDone(struct eap_sm *sm, void *priv)
484 {
485 struct eap_pax_data *data = priv;
486 return data->state == SUCCESS || data->state == FAILURE;
487 }
488
489
eap_pax_getKey(struct eap_sm * sm,void * priv,size_t * len)490 static u8 * eap_pax_getKey(struct eap_sm *sm, void *priv, size_t *len)
491 {
492 struct eap_pax_data *data = priv;
493 u8 *key;
494
495 if (data->state != SUCCESS)
496 return NULL;
497
498 key = os_malloc(EAP_MSK_LEN);
499 if (key == NULL)
500 return NULL;
501
502 *len = EAP_MSK_LEN;
503 eap_pax_kdf(data->mac_id, data->mk, EAP_PAX_MK_LEN,
504 "Master Session Key", data->rand.e, 2 * EAP_PAX_RAND_LEN,
505 EAP_MSK_LEN, key);
506
507 return key;
508 }
509
510
eap_pax_get_emsk(struct eap_sm * sm,void * priv,size_t * len)511 static u8 * eap_pax_get_emsk(struct eap_sm *sm, void *priv, size_t *len)
512 {
513 struct eap_pax_data *data = priv;
514 u8 *key;
515
516 if (data->state != SUCCESS)
517 return NULL;
518
519 key = os_malloc(EAP_EMSK_LEN);
520 if (key == NULL)
521 return NULL;
522
523 *len = EAP_EMSK_LEN;
524 eap_pax_kdf(data->mac_id, data->mk, EAP_PAX_MK_LEN,
525 "Extended Master Session Key",
526 data->rand.e, 2 * EAP_PAX_RAND_LEN,
527 EAP_EMSK_LEN, key);
528
529 return key;
530 }
531
532
eap_pax_isSuccess(struct eap_sm * sm,void * priv)533 static Boolean eap_pax_isSuccess(struct eap_sm *sm, void *priv)
534 {
535 struct eap_pax_data *data = priv;
536 return data->state == SUCCESS;
537 }
538
539
eap_server_pax_register(void)540 int eap_server_pax_register(void)
541 {
542 struct eap_method *eap;
543 int ret;
544
545 eap = eap_server_method_alloc(EAP_SERVER_METHOD_INTERFACE_VERSION,
546 EAP_VENDOR_IETF, EAP_TYPE_PAX, "PAX");
547 if (eap == NULL)
548 return -1;
549
550 eap->init = eap_pax_init;
551 eap->reset = eap_pax_reset;
552 eap->buildReq = eap_pax_buildReq;
553 eap->check = eap_pax_check;
554 eap->process = eap_pax_process;
555 eap->isDone = eap_pax_isDone;
556 eap->getKey = eap_pax_getKey;
557 eap->isSuccess = eap_pax_isSuccess;
558 eap->get_emsk = eap_pax_get_emsk;
559
560 ret = eap_server_method_register(eap);
561 if (ret)
562 eap_server_method_free(eap);
563 return ret;
564 }
565