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, cid_len;
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 cid_len = WPA_GET_BE16(pos);
324 if (cid_len > 1500) {
325 wpa_printf(MSG_INFO, "EAP-PAX: Too long CID");
326 return;
327 }
328 data->cid_len = cid_len;
329 os_free(data->cid);
330 data->cid = os_malloc(data->cid_len);
331 if (data->cid == NULL) {
332 wpa_printf(MSG_INFO, "EAP-PAX: Failed to allocate memory for "
333 "CID");
334 return;
335 }
336 os_memcpy(data->cid, pos + 2, data->cid_len);
337 pos += 2 + data->cid_len;
338 left -= 2 + data->cid_len;
339 wpa_hexdump_ascii(MSG_MSGDUMP, "EAP-PAX: CID",
340 (u8 *) data->cid, data->cid_len);
341
342 if (left < 2 + EAP_PAX_MAC_LEN ||
343 WPA_GET_BE16(pos) != EAP_PAX_MAC_LEN) {
344 wpa_printf(MSG_INFO, "EAP-PAX: Too short PAX_STD-2 (MAC_CK)");
345 return;
346 }
347 pos += 2;
348 left -= 2;
349 wpa_hexdump(MSG_MSGDUMP, "EAP-PAX: MAC_CK(A, B, CID)",
350 pos, EAP_PAX_MAC_LEN);
351
352 if (eap_user_get(sm, (u8 *) data->cid, data->cid_len, 0) < 0) {
353 wpa_hexdump_ascii(MSG_DEBUG, "EAP-PAX: unknown CID",
354 (u8 *) data->cid, data->cid_len);
355 data->state = FAILURE;
356 return;
357 }
358
359 for (i = 0;
360 i < EAP_MAX_METHODS &&
361 (sm->user->methods[i].vendor != EAP_VENDOR_IETF ||
362 sm->user->methods[i].method != EAP_TYPE_NONE);
363 i++) {
364 if (sm->user->methods[i].vendor == EAP_VENDOR_IETF &&
365 sm->user->methods[i].method == EAP_TYPE_PAX)
366 break;
367 }
368
369 if (i >= EAP_MAX_METHODS ||
370 sm->user->methods[i].vendor != EAP_VENDOR_IETF ||
371 sm->user->methods[i].method != EAP_TYPE_PAX) {
372 wpa_hexdump_ascii(MSG_DEBUG,
373 "EAP-PAX: EAP-PAX not enabled for CID",
374 (u8 *) data->cid, data->cid_len);
375 data->state = FAILURE;
376 return;
377 }
378
379 if (sm->user->password == NULL ||
380 sm->user->password_len != EAP_PAX_AK_LEN) {
381 wpa_hexdump_ascii(MSG_DEBUG, "EAP-PAX: invalid password in "
382 "user database for CID",
383 (u8 *) data->cid, data->cid_len);
384 data->state = FAILURE;
385 return;
386 }
387 os_memcpy(data->ak, sm->user->password, EAP_PAX_AK_LEN);
388
389 if (eap_pax_initial_key_derivation(data->mac_id, data->ak,
390 data->rand.e, data->mk, data->ck,
391 data->ick) < 0) {
392 wpa_printf(MSG_INFO, "EAP-PAX: Failed to complete initial "
393 "key derivation");
394 data->state = FAILURE;
395 return;
396 }
397 data->keys_set = 1;
398
399 eap_pax_mac(data->mac_id, data->ck, EAP_PAX_CK_LEN,
400 data->rand.r.x, EAP_PAX_RAND_LEN,
401 data->rand.r.y, EAP_PAX_RAND_LEN,
402 (u8 *) data->cid, data->cid_len, mac);
403 if (os_memcmp_const(mac, pos, EAP_PAX_MAC_LEN) != 0) {
404 wpa_printf(MSG_INFO, "EAP-PAX: Invalid MAC_CK(A, B, CID) in "
405 "PAX_STD-2");
406 wpa_hexdump(MSG_MSGDUMP, "EAP-PAX: Expected MAC_CK(A, B, CID)",
407 mac, EAP_PAX_MAC_LEN);
408 data->state = FAILURE;
409 return;
410 }
411
412 pos += EAP_PAX_MAC_LEN;
413 left -= EAP_PAX_MAC_LEN;
414
415 if (left < EAP_PAX_ICV_LEN) {
416 wpa_printf(MSG_INFO, "EAP-PAX: Too short ICV (%lu) in "
417 "PAX_STD-2", (unsigned long) left);
418 return;
419 }
420 wpa_hexdump(MSG_MSGDUMP, "EAP-PAX: ICV", pos, EAP_PAX_ICV_LEN);
421 eap_pax_mac(data->mac_id, data->ick, EAP_PAX_ICK_LEN,
422 wpabuf_head(respData),
423 wpabuf_len(respData) - EAP_PAX_ICV_LEN, NULL, 0, NULL, 0,
424 icvbuf);
425 if (os_memcmp_const(icvbuf, pos, EAP_PAX_ICV_LEN) != 0) {
426 wpa_printf(MSG_INFO, "EAP-PAX: Invalid ICV in PAX_STD-2");
427 wpa_hexdump(MSG_MSGDUMP, "EAP-PAX: Expected ICV",
428 icvbuf, EAP_PAX_ICV_LEN);
429 return;
430 }
431 pos += EAP_PAX_ICV_LEN;
432 left -= EAP_PAX_ICV_LEN;
433
434 if (left > 0) {
435 wpa_hexdump(MSG_MSGDUMP, "EAP-PAX: ignored extra payload",
436 pos, left);
437 }
438
439 data->state = PAX_STD_3;
440 }
441
442
eap_pax_process_ack(struct eap_sm * sm,struct eap_pax_data * data,struct wpabuf * respData)443 static void eap_pax_process_ack(struct eap_sm *sm,
444 struct eap_pax_data *data,
445 struct wpabuf *respData)
446 {
447 if (data->state != PAX_STD_3)
448 return;
449
450 wpa_printf(MSG_DEBUG, "EAP-PAX: Received PAX-ACK - authentication "
451 "completed successfully");
452 data->state = SUCCESS;
453 }
454
455
eap_pax_process(struct eap_sm * sm,void * priv,struct wpabuf * respData)456 static void eap_pax_process(struct eap_sm *sm, void *priv,
457 struct wpabuf *respData)
458 {
459 struct eap_pax_data *data = priv;
460 struct eap_pax_hdr *resp;
461 const u8 *pos;
462 size_t len;
463
464 if (sm->user == NULL || sm->user->password == NULL) {
465 wpa_printf(MSG_INFO, "EAP-PAX: Plaintext password not "
466 "configured");
467 data->state = FAILURE;
468 return;
469 }
470
471 pos = eap_hdr_validate(EAP_VENDOR_IETF, EAP_TYPE_PAX, respData, &len);
472 if (pos == NULL || len < sizeof(*resp))
473 return;
474
475 resp = (struct eap_pax_hdr *) pos;
476
477 switch (resp->op_code) {
478 case EAP_PAX_OP_STD_2:
479 eap_pax_process_std_2(sm, data, respData);
480 break;
481 case EAP_PAX_OP_ACK:
482 eap_pax_process_ack(sm, data, respData);
483 break;
484 }
485 }
486
487
eap_pax_isDone(struct eap_sm * sm,void * priv)488 static Boolean eap_pax_isDone(struct eap_sm *sm, void *priv)
489 {
490 struct eap_pax_data *data = priv;
491 return data->state == SUCCESS || data->state == FAILURE;
492 }
493
494
eap_pax_getKey(struct eap_sm * sm,void * priv,size_t * len)495 static u8 * eap_pax_getKey(struct eap_sm *sm, void *priv, size_t *len)
496 {
497 struct eap_pax_data *data = priv;
498 u8 *key;
499
500 if (data->state != SUCCESS)
501 return NULL;
502
503 key = os_malloc(EAP_MSK_LEN);
504 if (key == NULL)
505 return NULL;
506
507 *len = EAP_MSK_LEN;
508 eap_pax_kdf(data->mac_id, data->mk, EAP_PAX_MK_LEN,
509 "Master Session Key", data->rand.e, 2 * EAP_PAX_RAND_LEN,
510 EAP_MSK_LEN, key);
511
512 return key;
513 }
514
515
eap_pax_get_emsk(struct eap_sm * sm,void * priv,size_t * len)516 static u8 * eap_pax_get_emsk(struct eap_sm *sm, void *priv, size_t *len)
517 {
518 struct eap_pax_data *data = priv;
519 u8 *key;
520
521 if (data->state != SUCCESS)
522 return NULL;
523
524 key = os_malloc(EAP_EMSK_LEN);
525 if (key == NULL)
526 return NULL;
527
528 *len = EAP_EMSK_LEN;
529 eap_pax_kdf(data->mac_id, data->mk, EAP_PAX_MK_LEN,
530 "Extended Master Session Key",
531 data->rand.e, 2 * EAP_PAX_RAND_LEN,
532 EAP_EMSK_LEN, key);
533
534 return key;
535 }
536
537
eap_pax_isSuccess(struct eap_sm * sm,void * priv)538 static Boolean eap_pax_isSuccess(struct eap_sm *sm, void *priv)
539 {
540 struct eap_pax_data *data = priv;
541 return data->state == SUCCESS;
542 }
543
544
eap_server_pax_register(void)545 int eap_server_pax_register(void)
546 {
547 struct eap_method *eap;
548 int ret;
549
550 eap = eap_server_method_alloc(EAP_SERVER_METHOD_INTERFACE_VERSION,
551 EAP_VENDOR_IETF, EAP_TYPE_PAX, "PAX");
552 if (eap == NULL)
553 return -1;
554
555 eap->init = eap_pax_init;
556 eap->reset = eap_pax_reset;
557 eap->buildReq = eap_pax_buildReq;
558 eap->check = eap_pax_check;
559 eap->process = eap_pax_process;
560 eap->isDone = eap_pax_isDone;
561 eap->getKey = eap_pax_getKey;
562 eap->isSuccess = eap_pax_isSuccess;
563 eap->get_emsk = eap_pax_get_emsk;
564
565 ret = eap_server_method_register(eap);
566 if (ret)
567 eap_server_method_free(eap);
568 return ret;
569 }
570