Line data Source code
1 : /*
2 : * EAP peer method: EAP-PAX (RFC 4746)
3 : * Copyright (c) 2005-2008, 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_common/eap_pax_common.h"
14 : #include "eap_i.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_INIT, PAX_STD_2_SENT, PAX_DONE } state;
27 : u8 mac_id, dh_group_id, public_key_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 : char *cid;
36 : size_t cid_len;
37 : u8 ak[EAP_PAX_AK_LEN];
38 : u8 mk[EAP_PAX_MK_LEN];
39 : u8 ck[EAP_PAX_CK_LEN];
40 : u8 ick[EAP_PAX_ICK_LEN];
41 : };
42 :
43 :
44 : static void eap_pax_deinit(struct eap_sm *sm, void *priv);
45 :
46 :
47 14 : static void * eap_pax_init(struct eap_sm *sm)
48 : {
49 : struct eap_pax_data *data;
50 : const u8 *identity, *password;
51 : size_t identity_len, password_len;
52 :
53 14 : identity = eap_get_config_identity(sm, &identity_len);
54 14 : password = eap_get_config_password(sm, &password_len);
55 14 : if (!identity || !password) {
56 0 : wpa_printf(MSG_INFO, "EAP-PAX: CID (nai) or key (password) "
57 : "not configured");
58 0 : return NULL;
59 : }
60 :
61 14 : if (password_len != EAP_PAX_AK_LEN) {
62 0 : wpa_printf(MSG_INFO, "EAP-PAX: Invalid PSK length");
63 0 : return NULL;
64 : }
65 :
66 14 : data = os_zalloc(sizeof(*data));
67 14 : if (data == NULL)
68 0 : return NULL;
69 14 : data->state = PAX_INIT;
70 :
71 14 : data->cid = os_malloc(identity_len);
72 14 : if (data->cid == NULL) {
73 0 : eap_pax_deinit(sm, data);
74 0 : return NULL;
75 : }
76 14 : os_memcpy(data->cid, identity, identity_len);
77 14 : data->cid_len = identity_len;
78 :
79 14 : os_memcpy(data->ak, password, EAP_PAX_AK_LEN);
80 :
81 14 : return data;
82 : }
83 :
84 :
85 14 : static void eap_pax_deinit(struct eap_sm *sm, void *priv)
86 : {
87 14 : struct eap_pax_data *data = priv;
88 14 : os_free(data->cid);
89 14 : os_free(data);
90 14 : }
91 :
92 :
93 27 : static struct wpabuf * eap_pax_alloc_resp(const struct eap_pax_hdr *req,
94 : u8 id, u8 op_code, size_t plen)
95 : {
96 : struct wpabuf *resp;
97 : struct eap_pax_hdr *pax;
98 :
99 27 : resp = eap_msg_alloc(EAP_VENDOR_IETF, EAP_TYPE_PAX,
100 : sizeof(*pax) + plen, EAP_CODE_RESPONSE, id);
101 27 : if (resp == NULL)
102 0 : return NULL;
103 :
104 27 : pax = wpabuf_put(resp, sizeof(*pax));
105 27 : pax->op_code = op_code;
106 27 : pax->flags = 0;
107 27 : pax->mac_id = req->mac_id;
108 27 : pax->dh_group_id = req->dh_group_id;
109 27 : pax->public_key_id = req->public_key_id;
110 :
111 27 : return resp;
112 : }
113 :
114 :
115 14 : static struct wpabuf * eap_pax_process_std_1(struct eap_pax_data *data,
116 : struct eap_method_ret *ret, u8 id,
117 : const struct eap_pax_hdr *req,
118 : size_t req_plen)
119 : {
120 : struct wpabuf *resp;
121 : const u8 *pos;
122 : u8 *rpos;
123 : size_t left, plen;
124 :
125 14 : wpa_printf(MSG_DEBUG, "EAP-PAX: PAX_STD-1 (received)");
126 :
127 14 : if (data->state != PAX_INIT) {
128 0 : wpa_printf(MSG_INFO, "EAP-PAX: PAX_STD-1 received in "
129 0 : "unexpected state (%d) - ignored", data->state);
130 0 : ret->ignore = TRUE;
131 0 : return NULL;
132 : }
133 :
134 14 : if (req->flags & EAP_PAX_FLAGS_CE) {
135 0 : wpa_printf(MSG_INFO, "EAP-PAX: PAX_STD-1 with CE flag set - "
136 : "ignored");
137 0 : ret->ignore = TRUE;
138 0 : return NULL;
139 : }
140 :
141 14 : left = req_plen - sizeof(*req);
142 :
143 14 : if (left < 2 + EAP_PAX_RAND_LEN) {
144 0 : wpa_printf(MSG_INFO, "EAP-PAX: PAX_STD-1 with too short "
145 : "payload");
146 0 : ret->ignore = TRUE;
147 0 : return NULL;
148 : }
149 :
150 14 : pos = (const u8 *) (req + 1);
151 14 : if (WPA_GET_BE16(pos) != EAP_PAX_RAND_LEN) {
152 0 : wpa_printf(MSG_INFO, "EAP-PAX: PAX_STD-1 with incorrect A "
153 : "length %d (expected %d)",
154 0 : WPA_GET_BE16(pos), EAP_PAX_RAND_LEN);
155 0 : ret->ignore = TRUE;
156 0 : return NULL;
157 : }
158 :
159 14 : pos += 2;
160 14 : left -= 2;
161 14 : os_memcpy(data->rand.r.x, pos, EAP_PAX_RAND_LEN);
162 14 : wpa_hexdump(MSG_MSGDUMP, "EAP-PAX: X (server rand)",
163 14 : data->rand.r.x, EAP_PAX_RAND_LEN);
164 14 : pos += EAP_PAX_RAND_LEN;
165 14 : left -= EAP_PAX_RAND_LEN;
166 :
167 14 : if (left > 0) {
168 0 : wpa_hexdump(MSG_MSGDUMP, "EAP-PAX: ignored extra payload",
169 : pos, left);
170 : }
171 :
172 14 : if (random_get_bytes(data->rand.r.y, EAP_PAX_RAND_LEN)) {
173 0 : wpa_printf(MSG_ERROR, "EAP-PAX: Failed to get random data");
174 0 : ret->ignore = TRUE;
175 0 : return NULL;
176 : }
177 14 : wpa_hexdump(MSG_MSGDUMP, "EAP-PAX: Y (client rand)",
178 14 : data->rand.r.y, EAP_PAX_RAND_LEN);
179 :
180 14 : if (eap_pax_initial_key_derivation(req->mac_id, data->ak, data->rand.e,
181 14 : data->mk, data->ck, data->ick) < 0)
182 : {
183 0 : ret->ignore = TRUE;
184 0 : return NULL;
185 : }
186 :
187 14 : wpa_printf(MSG_DEBUG, "EAP-PAX: PAX_STD-2 (sending)");
188 :
189 14 : plen = 2 + EAP_PAX_RAND_LEN + 2 + data->cid_len + 2 + EAP_PAX_MAC_LEN +
190 : EAP_PAX_ICV_LEN;
191 14 : resp = eap_pax_alloc_resp(req, id, EAP_PAX_OP_STD_2, plen);
192 14 : if (resp == NULL)
193 0 : return NULL;
194 :
195 14 : wpabuf_put_be16(resp, EAP_PAX_RAND_LEN);
196 14 : wpabuf_put_data(resp, data->rand.r.y, EAP_PAX_RAND_LEN);
197 14 : wpa_hexdump(MSG_MSGDUMP, "EAP-PAX: B = Y (client rand)",
198 14 : data->rand.r.y, EAP_PAX_RAND_LEN);
199 :
200 14 : wpabuf_put_be16(resp, data->cid_len);
201 14 : wpabuf_put_data(resp, data->cid, data->cid_len);
202 28 : wpa_hexdump_ascii(MSG_MSGDUMP, "EAP-PAX: CID",
203 14 : (u8 *) data->cid, data->cid_len);
204 :
205 14 : wpabuf_put_be16(resp, EAP_PAX_MAC_LEN);
206 14 : rpos = wpabuf_put(resp, EAP_PAX_MAC_LEN);
207 28 : eap_pax_mac(req->mac_id, data->ck, EAP_PAX_CK_LEN,
208 14 : data->rand.r.x, EAP_PAX_RAND_LEN,
209 14 : data->rand.r.y, EAP_PAX_RAND_LEN,
210 14 : (u8 *) data->cid, data->cid_len, rpos);
211 14 : wpa_hexdump(MSG_MSGDUMP, "EAP-PAX: MAC_CK(A, B, CID)",
212 : rpos, EAP_PAX_MAC_LEN);
213 :
214 : /* Optional ADE could be added here, if needed */
215 :
216 14 : rpos = wpabuf_put(resp, EAP_PAX_ICV_LEN);
217 28 : eap_pax_mac(req->mac_id, data->ick, EAP_PAX_ICK_LEN,
218 28 : wpabuf_head(resp), wpabuf_len(resp) - EAP_PAX_ICV_LEN,
219 : NULL, 0, NULL, 0, rpos);
220 14 : wpa_hexdump(MSG_MSGDUMP, "EAP-PAX: ICV", rpos, EAP_PAX_ICV_LEN);
221 :
222 14 : data->state = PAX_STD_2_SENT;
223 14 : data->mac_id = req->mac_id;
224 14 : data->dh_group_id = req->dh_group_id;
225 14 : data->public_key_id = req->public_key_id;
226 :
227 14 : return resp;
228 : }
229 :
230 :
231 13 : static struct wpabuf * eap_pax_process_std_3(struct eap_pax_data *data,
232 : struct eap_method_ret *ret, u8 id,
233 : const struct eap_pax_hdr *req,
234 : size_t req_plen)
235 : {
236 : struct wpabuf *resp;
237 : u8 *rpos, mac[EAP_PAX_MAC_LEN];
238 : const u8 *pos;
239 : size_t left;
240 :
241 13 : wpa_printf(MSG_DEBUG, "EAP-PAX: PAX_STD-3 (received)");
242 :
243 13 : if (data->state != PAX_STD_2_SENT) {
244 0 : wpa_printf(MSG_INFO, "EAP-PAX: PAX_STD-3 received in "
245 0 : "unexpected state (%d) - ignored", data->state);
246 0 : ret->ignore = TRUE;
247 0 : return NULL;
248 : }
249 :
250 13 : if (req->flags & EAP_PAX_FLAGS_CE) {
251 0 : wpa_printf(MSG_INFO, "EAP-PAX: PAX_STD-3 with CE flag set - "
252 : "ignored");
253 0 : ret->ignore = TRUE;
254 0 : return NULL;
255 : }
256 :
257 13 : left = req_plen - sizeof(*req);
258 :
259 13 : if (left < 2 + EAP_PAX_MAC_LEN) {
260 0 : wpa_printf(MSG_INFO, "EAP-PAX: PAX_STD-3 with too short "
261 : "payload");
262 0 : ret->ignore = TRUE;
263 0 : return NULL;
264 : }
265 :
266 13 : pos = (const u8 *) (req + 1);
267 13 : if (WPA_GET_BE16(pos) != EAP_PAX_MAC_LEN) {
268 0 : wpa_printf(MSG_INFO, "EAP-PAX: PAX_STD-3 with incorrect "
269 : "MAC_CK length %d (expected %d)",
270 0 : WPA_GET_BE16(pos), EAP_PAX_MAC_LEN);
271 0 : ret->ignore = TRUE;
272 0 : return NULL;
273 : }
274 13 : pos += 2;
275 13 : left -= 2;
276 13 : wpa_hexdump(MSG_MSGDUMP, "EAP-PAX: MAC_CK(B, CID)",
277 : pos, EAP_PAX_MAC_LEN);
278 26 : eap_pax_mac(data->mac_id, data->ck, EAP_PAX_CK_LEN,
279 13 : data->rand.r.y, EAP_PAX_RAND_LEN,
280 13 : (u8 *) data->cid, data->cid_len, NULL, 0, mac);
281 13 : if (os_memcmp(pos, mac, EAP_PAX_MAC_LEN) != 0) {
282 0 : wpa_printf(MSG_INFO, "EAP-PAX: Invalid MAC_CK(B, CID) "
283 : "received");
284 0 : wpa_hexdump(MSG_MSGDUMP, "EAP-PAX: expected MAC_CK(B, CID)",
285 : mac, EAP_PAX_MAC_LEN);
286 0 : ret->methodState = METHOD_DONE;
287 0 : ret->decision = DECISION_FAIL;
288 0 : return NULL;
289 : }
290 :
291 13 : pos += EAP_PAX_MAC_LEN;
292 13 : left -= EAP_PAX_MAC_LEN;
293 :
294 13 : if (left > 0) {
295 0 : wpa_hexdump(MSG_MSGDUMP, "EAP-PAX: ignored extra payload",
296 : pos, left);
297 : }
298 :
299 13 : wpa_printf(MSG_DEBUG, "EAP-PAX: PAX-ACK (sending)");
300 :
301 13 : resp = eap_pax_alloc_resp(req, id, EAP_PAX_OP_ACK, EAP_PAX_ICV_LEN);
302 13 : if (resp == NULL)
303 0 : return NULL;
304 :
305 : /* Optional ADE could be added here, if needed */
306 :
307 13 : rpos = wpabuf_put(resp, EAP_PAX_ICV_LEN);
308 26 : eap_pax_mac(data->mac_id, data->ick, EAP_PAX_ICK_LEN,
309 26 : wpabuf_head(resp), wpabuf_len(resp) - EAP_PAX_ICV_LEN,
310 : NULL, 0, NULL, 0, rpos);
311 13 : wpa_hexdump(MSG_MSGDUMP, "EAP-PAX: ICV", rpos, EAP_PAX_ICV_LEN);
312 :
313 13 : data->state = PAX_DONE;
314 13 : ret->methodState = METHOD_DONE;
315 13 : ret->decision = DECISION_UNCOND_SUCC;
316 13 : ret->allowNotifications = FALSE;
317 :
318 13 : return resp;
319 : }
320 :
321 :
322 27 : static struct wpabuf * eap_pax_process(struct eap_sm *sm, void *priv,
323 : struct eap_method_ret *ret,
324 : const struct wpabuf *reqData)
325 : {
326 27 : struct eap_pax_data *data = priv;
327 : const struct eap_pax_hdr *req;
328 : struct wpabuf *resp;
329 : u8 icvbuf[EAP_PAX_ICV_LEN], id;
330 : const u8 *icv, *pos;
331 : size_t len;
332 : u16 flen, mlen;
333 :
334 27 : pos = eap_hdr_validate(EAP_VENDOR_IETF, EAP_TYPE_PAX, reqData, &len);
335 27 : if (pos == NULL || len < EAP_PAX_ICV_LEN) {
336 0 : ret->ignore = TRUE;
337 0 : return NULL;
338 : }
339 27 : id = eap_get_id(reqData);
340 27 : req = (const struct eap_pax_hdr *) pos;
341 27 : flen = len - EAP_PAX_ICV_LEN;
342 27 : mlen = wpabuf_len(reqData) - EAP_PAX_ICV_LEN;
343 :
344 135 : wpa_printf(MSG_DEBUG, "EAP-PAX: received frame: op_code 0x%x "
345 : "flags 0x%x mac_id 0x%x dh_group_id 0x%x "
346 : "public_key_id 0x%x",
347 108 : req->op_code, req->flags, req->mac_id, req->dh_group_id,
348 27 : req->public_key_id);
349 27 : wpa_hexdump(MSG_MSGDUMP, "EAP-PAX: received payload",
350 : pos, len - EAP_PAX_ICV_LEN);
351 :
352 27 : if (data->state != PAX_INIT && data->mac_id != req->mac_id) {
353 0 : wpa_printf(MSG_INFO, "EAP-PAX: MAC ID changed during "
354 : "authentication (was 0x%d, is 0x%d)",
355 0 : data->mac_id, req->mac_id);
356 0 : ret->ignore = TRUE;
357 0 : return NULL;
358 : }
359 :
360 27 : if (data->state != PAX_INIT && data->dh_group_id != req->dh_group_id) {
361 0 : wpa_printf(MSG_INFO, "EAP-PAX: DH Group ID changed during "
362 : "authentication (was 0x%d, is 0x%d)",
363 0 : data->dh_group_id, req->dh_group_id);
364 0 : ret->ignore = TRUE;
365 0 : return NULL;
366 : }
367 :
368 40 : if (data->state != PAX_INIT &&
369 13 : data->public_key_id != req->public_key_id) {
370 0 : wpa_printf(MSG_INFO, "EAP-PAX: Public Key ID changed during "
371 : "authentication (was 0x%d, is 0x%d)",
372 0 : data->public_key_id, req->public_key_id);
373 0 : ret->ignore = TRUE;
374 0 : return NULL;
375 : }
376 :
377 : /* TODO: add support EAP_PAX_HMAC_SHA256_128 */
378 27 : if (req->mac_id != EAP_PAX_MAC_HMAC_SHA1_128) {
379 0 : wpa_printf(MSG_INFO, "EAP-PAX: Unsupported MAC ID 0x%x",
380 0 : req->mac_id);
381 0 : ret->ignore = TRUE;
382 0 : return NULL;
383 : }
384 :
385 27 : if (req->dh_group_id != EAP_PAX_DH_GROUP_NONE) {
386 0 : wpa_printf(MSG_INFO, "EAP-PAX: Unsupported DH Group ID 0x%x",
387 0 : req->dh_group_id);
388 0 : ret->ignore = TRUE;
389 0 : return NULL;
390 : }
391 :
392 27 : if (req->public_key_id != EAP_PAX_PUBLIC_KEY_NONE) {
393 0 : wpa_printf(MSG_INFO, "EAP-PAX: Unsupported Public Key ID 0x%x",
394 0 : req->public_key_id);
395 0 : ret->ignore = TRUE;
396 0 : return NULL;
397 : }
398 :
399 27 : if (req->flags & EAP_PAX_FLAGS_MF) {
400 : /* TODO: add support for reassembling fragments */
401 0 : wpa_printf(MSG_INFO, "EAP-PAX: fragmentation not supported - "
402 : "ignored packet");
403 0 : ret->ignore = TRUE;
404 0 : return NULL;
405 : }
406 :
407 27 : icv = pos + len - EAP_PAX_ICV_LEN;
408 27 : wpa_hexdump(MSG_MSGDUMP, "EAP-PAX: ICV", icv, EAP_PAX_ICV_LEN);
409 27 : if (req->op_code == EAP_PAX_OP_STD_1) {
410 28 : eap_pax_mac(req->mac_id, (u8 *) "", 0,
411 14 : wpabuf_head(reqData), mlen, NULL, 0, NULL, 0,
412 : icvbuf);
413 : } else {
414 26 : eap_pax_mac(req->mac_id, data->ick, EAP_PAX_ICK_LEN,
415 13 : wpabuf_head(reqData), mlen, NULL, 0, NULL, 0,
416 : icvbuf);
417 : }
418 27 : if (os_memcmp(icv, icvbuf, EAP_PAX_ICV_LEN) != 0) {
419 0 : wpa_printf(MSG_DEBUG, "EAP-PAX: invalid ICV - ignoring the "
420 : "message");
421 0 : wpa_hexdump(MSG_MSGDUMP, "EAP-PAX: expected ICV",
422 : icvbuf, EAP_PAX_ICV_LEN);
423 0 : ret->ignore = TRUE;
424 0 : return NULL;
425 : }
426 :
427 27 : ret->ignore = FALSE;
428 27 : ret->methodState = METHOD_MAY_CONT;
429 27 : ret->decision = DECISION_FAIL;
430 27 : ret->allowNotifications = TRUE;
431 :
432 27 : switch (req->op_code) {
433 : case EAP_PAX_OP_STD_1:
434 14 : resp = eap_pax_process_std_1(data, ret, id, req, flen);
435 14 : break;
436 : case EAP_PAX_OP_STD_3:
437 13 : resp = eap_pax_process_std_3(data, ret, id, req, flen);
438 13 : break;
439 : default:
440 0 : wpa_printf(MSG_DEBUG, "EAP-PAX: ignoring message with unknown "
441 0 : "op_code %d", req->op_code);
442 0 : ret->ignore = TRUE;
443 0 : return NULL;
444 : }
445 :
446 27 : if (ret->methodState == METHOD_DONE) {
447 13 : ret->allowNotifications = FALSE;
448 : }
449 :
450 27 : return resp;
451 : }
452 :
453 :
454 27 : static Boolean eap_pax_isKeyAvailable(struct eap_sm *sm, void *priv)
455 : {
456 27 : struct eap_pax_data *data = priv;
457 27 : return data->state == PAX_DONE;
458 : }
459 :
460 :
461 13 : static u8 * eap_pax_getKey(struct eap_sm *sm, void *priv, size_t *len)
462 : {
463 13 : struct eap_pax_data *data = priv;
464 : u8 *key;
465 :
466 13 : if (data->state != PAX_DONE)
467 0 : return NULL;
468 :
469 13 : key = os_malloc(EAP_MSK_LEN);
470 13 : if (key == NULL)
471 0 : return NULL;
472 :
473 13 : *len = EAP_MSK_LEN;
474 13 : eap_pax_kdf(data->mac_id, data->mk, EAP_PAX_MK_LEN,
475 13 : "Master Session Key", data->rand.e, 2 * EAP_PAX_RAND_LEN,
476 : EAP_MSK_LEN, key);
477 :
478 13 : return key;
479 : }
480 :
481 :
482 0 : static u8 * eap_pax_get_emsk(struct eap_sm *sm, void *priv, size_t *len)
483 : {
484 0 : struct eap_pax_data *data = priv;
485 : u8 *key;
486 :
487 0 : if (data->state != PAX_DONE)
488 0 : return NULL;
489 :
490 0 : key = os_malloc(EAP_EMSK_LEN);
491 0 : if (key == NULL)
492 0 : return NULL;
493 :
494 0 : *len = EAP_EMSK_LEN;
495 0 : eap_pax_kdf(data->mac_id, data->mk, EAP_PAX_MK_LEN,
496 : "Extended Master Session Key",
497 0 : data->rand.e, 2 * EAP_PAX_RAND_LEN,
498 : EAP_EMSK_LEN, key);
499 :
500 0 : return key;
501 : }
502 :
503 :
504 4 : int eap_peer_pax_register(void)
505 : {
506 : struct eap_method *eap;
507 : int ret;
508 :
509 4 : eap = eap_peer_method_alloc(EAP_PEER_METHOD_INTERFACE_VERSION,
510 : EAP_VENDOR_IETF, EAP_TYPE_PAX, "PAX");
511 4 : if (eap == NULL)
512 0 : return -1;
513 :
514 4 : eap->init = eap_pax_init;
515 4 : eap->deinit = eap_pax_deinit;
516 4 : eap->process = eap_pax_process;
517 4 : eap->isKeyAvailable = eap_pax_isKeyAvailable;
518 4 : eap->getKey = eap_pax_getKey;
519 4 : eap->get_emsk = eap_pax_get_emsk;
520 :
521 4 : ret = eap_peer_method_register(eap);
522 4 : if (ret)
523 0 : eap_peer_method_free(eap);
524 4 : return ret;
525 : }
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