1 /*
2 * EAP server method: EAP-TNC (Trusted Network Connect)
3 * Copyright (c) 2007-2010, 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 "eap_i.h"
13 #include "tncs.h"
14
15
16 struct eap_tnc_data {
17 enum eap_tnc_state {
18 START, CONTINUE, RECOMMENDATION, FRAG_ACK, WAIT_FRAG_ACK, DONE,
19 FAIL
20 } state;
21 enum { ALLOW, ISOLATE, NO_ACCESS, NO_RECOMMENDATION } recommendation;
22 struct tncs_data *tncs;
23 struct wpabuf *in_buf;
24 struct wpabuf *out_buf;
25 size_t out_used;
26 size_t fragment_size;
27 unsigned int was_done:1;
28 unsigned int was_fail:1;
29 };
30
31
32 /* EAP-TNC Flags */
33 #define EAP_TNC_FLAGS_LENGTH_INCLUDED 0x80
34 #define EAP_TNC_FLAGS_MORE_FRAGMENTS 0x40
35 #define EAP_TNC_FLAGS_START 0x20
36 #define EAP_TNC_VERSION_MASK 0x07
37
38 #define EAP_TNC_VERSION 1
39
40
eap_tnc_state_txt(enum eap_tnc_state state)41 static const char * eap_tnc_state_txt(enum eap_tnc_state state)
42 {
43 switch (state) {
44 case START:
45 return "START";
46 case CONTINUE:
47 return "CONTINUE";
48 case RECOMMENDATION:
49 return "RECOMMENDATION";
50 case FRAG_ACK:
51 return "FRAG_ACK";
52 case WAIT_FRAG_ACK:
53 return "WAIT_FRAG_ACK";
54 case DONE:
55 return "DONE";
56 case FAIL:
57 return "FAIL";
58 }
59 return "??";
60 }
61
62
eap_tnc_set_state(struct eap_tnc_data * data,enum eap_tnc_state new_state)63 static void eap_tnc_set_state(struct eap_tnc_data *data,
64 enum eap_tnc_state new_state)
65 {
66 wpa_printf(MSG_DEBUG, "EAP-TNC: %s -> %s",
67 eap_tnc_state_txt(data->state),
68 eap_tnc_state_txt(new_state));
69 data->state = new_state;
70 }
71
72
eap_tnc_init(struct eap_sm * sm)73 static void * eap_tnc_init(struct eap_sm *sm)
74 {
75 struct eap_tnc_data *data;
76
77 data = os_zalloc(sizeof(*data));
78 if (data == NULL)
79 return NULL;
80 eap_tnc_set_state(data, START);
81 data->tncs = tncs_init();
82 if (data->tncs == NULL) {
83 os_free(data);
84 return NULL;
85 }
86
87 data->fragment_size = sm->cfg->fragment_size > 100 ?
88 sm->cfg->fragment_size - 98 : 1300;
89
90 return data;
91 }
92
93
eap_tnc_reset(struct eap_sm * sm,void * priv)94 static void eap_tnc_reset(struct eap_sm *sm, void *priv)
95 {
96 struct eap_tnc_data *data = priv;
97 wpabuf_free(data->in_buf);
98 wpabuf_free(data->out_buf);
99 tncs_deinit(data->tncs);
100 os_free(data);
101 }
102
103
eap_tnc_build_start(struct eap_sm * sm,struct eap_tnc_data * data,u8 id)104 static struct wpabuf * eap_tnc_build_start(struct eap_sm *sm,
105 struct eap_tnc_data *data, u8 id)
106 {
107 struct wpabuf *req;
108
109 req = eap_msg_alloc(EAP_VENDOR_IETF, EAP_TYPE_TNC, 1, EAP_CODE_REQUEST,
110 id);
111 if (req == NULL) {
112 wpa_printf(MSG_ERROR, "EAP-TNC: Failed to allocate memory for "
113 "request");
114 eap_tnc_set_state(data, FAIL);
115 return NULL;
116 }
117
118 wpabuf_put_u8(req, EAP_TNC_FLAGS_START | EAP_TNC_VERSION);
119
120 eap_tnc_set_state(data, CONTINUE);
121
122 return req;
123 }
124
125
eap_tnc_build(struct eap_sm * sm,struct eap_tnc_data * data)126 static struct wpabuf * eap_tnc_build(struct eap_sm *sm,
127 struct eap_tnc_data *data)
128 {
129 struct wpabuf *req;
130 u8 *rpos, *rpos1;
131 size_t rlen;
132 char *start_buf, *end_buf;
133 size_t start_len, end_len;
134 size_t imv_len;
135
136 imv_len = tncs_total_send_len(data->tncs);
137
138 start_buf = tncs_if_tnccs_start(data->tncs);
139 if (start_buf == NULL)
140 return NULL;
141 start_len = os_strlen(start_buf);
142 end_buf = tncs_if_tnccs_end();
143 if (end_buf == NULL) {
144 os_free(start_buf);
145 return NULL;
146 }
147 end_len = os_strlen(end_buf);
148
149 rlen = start_len + imv_len + end_len;
150 req = wpabuf_alloc(rlen);
151 if (req == NULL) {
152 os_free(start_buf);
153 os_free(end_buf);
154 return NULL;
155 }
156
157 wpabuf_put_data(req, start_buf, start_len);
158 os_free(start_buf);
159
160 rpos1 = wpabuf_put(req, 0);
161 rpos = tncs_copy_send_buf(data->tncs, rpos1);
162 wpabuf_put(req, rpos - rpos1);
163
164 wpabuf_put_data(req, end_buf, end_len);
165 os_free(end_buf);
166
167 wpa_hexdump_ascii(MSG_MSGDUMP, "EAP-TNC: Request",
168 wpabuf_head(req), wpabuf_len(req));
169
170 return req;
171 }
172
173
eap_tnc_build_recommendation(struct eap_sm * sm,struct eap_tnc_data * data)174 static struct wpabuf * eap_tnc_build_recommendation(struct eap_sm *sm,
175 struct eap_tnc_data *data)
176 {
177 switch (data->recommendation) {
178 case ALLOW:
179 eap_tnc_set_state(data, DONE);
180 break;
181 case ISOLATE:
182 eap_tnc_set_state(data, FAIL);
183 /* TODO: support assignment to a different VLAN */
184 break;
185 case NO_ACCESS:
186 eap_tnc_set_state(data, FAIL);
187 break;
188 case NO_RECOMMENDATION:
189 eap_tnc_set_state(data, DONE);
190 break;
191 default:
192 wpa_printf(MSG_DEBUG, "EAP-TNC: Unknown recommendation");
193 return NULL;
194 }
195
196 return eap_tnc_build(sm, data);
197 }
198
199
eap_tnc_build_frag_ack(u8 id,u8 code)200 static struct wpabuf * eap_tnc_build_frag_ack(u8 id, u8 code)
201 {
202 struct wpabuf *msg;
203
204 msg = eap_msg_alloc(EAP_VENDOR_IETF, EAP_TYPE_TNC, 1, code, id);
205 if (msg == NULL) {
206 wpa_printf(MSG_ERROR, "EAP-TNC: Failed to allocate memory "
207 "for fragment ack");
208 return NULL;
209 }
210 wpabuf_put_u8(msg, EAP_TNC_VERSION); /* Flags */
211
212 wpa_printf(MSG_DEBUG, "EAP-TNC: Send fragment ack");
213
214 return msg;
215 }
216
217
eap_tnc_build_msg(struct eap_tnc_data * data,u8 id)218 static struct wpabuf * eap_tnc_build_msg(struct eap_tnc_data *data, u8 id)
219 {
220 struct wpabuf *req;
221 u8 flags;
222 size_t send_len, plen;
223
224 wpa_printf(MSG_DEBUG, "EAP-TNC: Generating Request");
225
226 flags = EAP_TNC_VERSION;
227 send_len = wpabuf_len(data->out_buf) - data->out_used;
228 if (1 + send_len > data->fragment_size) {
229 send_len = data->fragment_size - 1;
230 flags |= EAP_TNC_FLAGS_MORE_FRAGMENTS;
231 if (data->out_used == 0) {
232 flags |= EAP_TNC_FLAGS_LENGTH_INCLUDED;
233 send_len -= 4;
234 }
235 }
236
237 plen = 1 + send_len;
238 if (flags & EAP_TNC_FLAGS_LENGTH_INCLUDED)
239 plen += 4;
240 req = eap_msg_alloc(EAP_VENDOR_IETF, EAP_TYPE_TNC, plen,
241 EAP_CODE_REQUEST, id);
242 if (req == NULL)
243 return NULL;
244
245 wpabuf_put_u8(req, flags); /* Flags */
246 if (flags & EAP_TNC_FLAGS_LENGTH_INCLUDED)
247 wpabuf_put_be32(req, wpabuf_len(data->out_buf));
248
249 wpabuf_put_data(req, wpabuf_head_u8(data->out_buf) + data->out_used,
250 send_len);
251 data->out_used += send_len;
252
253 if (data->out_used == wpabuf_len(data->out_buf)) {
254 wpa_printf(MSG_DEBUG, "EAP-TNC: Sending out %lu bytes "
255 "(message sent completely)",
256 (unsigned long) send_len);
257 wpabuf_free(data->out_buf);
258 data->out_buf = NULL;
259 data->out_used = 0;
260 if (data->was_fail)
261 eap_tnc_set_state(data, FAIL);
262 else if (data->was_done)
263 eap_tnc_set_state(data, DONE);
264 } else {
265 wpa_printf(MSG_DEBUG, "EAP-TNC: Sending out %lu bytes "
266 "(%lu more to send)", (unsigned long) send_len,
267 (unsigned long) wpabuf_len(data->out_buf) -
268 data->out_used);
269 if (data->state == FAIL)
270 data->was_fail = 1;
271 else if (data->state == DONE)
272 data->was_done = 1;
273 eap_tnc_set_state(data, WAIT_FRAG_ACK);
274 }
275
276 return req;
277 }
278
279
eap_tnc_buildReq(struct eap_sm * sm,void * priv,u8 id)280 static struct wpabuf * eap_tnc_buildReq(struct eap_sm *sm, void *priv, u8 id)
281 {
282 struct eap_tnc_data *data = priv;
283
284 switch (data->state) {
285 case START:
286 tncs_init_connection(data->tncs);
287 return eap_tnc_build_start(sm, data, id);
288 case CONTINUE:
289 if (data->out_buf == NULL) {
290 data->out_buf = eap_tnc_build(sm, data);
291 if (data->out_buf == NULL) {
292 wpa_printf(MSG_DEBUG, "EAP-TNC: Failed to "
293 "generate message");
294 return NULL;
295 }
296 data->out_used = 0;
297 }
298 return eap_tnc_build_msg(data, id);
299 case RECOMMENDATION:
300 if (data->out_buf == NULL) {
301 data->out_buf = eap_tnc_build_recommendation(sm, data);
302 if (data->out_buf == NULL) {
303 wpa_printf(MSG_DEBUG, "EAP-TNC: Failed to "
304 "generate recommendation message");
305 return NULL;
306 }
307 data->out_used = 0;
308 }
309 return eap_tnc_build_msg(data, id);
310 case WAIT_FRAG_ACK:
311 return eap_tnc_build_msg(data, id);
312 case FRAG_ACK:
313 return eap_tnc_build_frag_ack(id, EAP_CODE_REQUEST);
314 case DONE:
315 case FAIL:
316 return NULL;
317 }
318
319 return NULL;
320 }
321
322
eap_tnc_check(struct eap_sm * sm,void * priv,struct wpabuf * respData)323 static bool eap_tnc_check(struct eap_sm *sm, void *priv,
324 struct wpabuf *respData)
325 {
326 struct eap_tnc_data *data = priv;
327 const u8 *pos;
328 size_t len;
329
330 pos = eap_hdr_validate(EAP_VENDOR_IETF, EAP_TYPE_TNC, respData,
331 &len);
332 if (pos == NULL) {
333 wpa_printf(MSG_INFO, "EAP-TNC: Invalid frame");
334 return true;
335 }
336
337 if (len == 0 && data->state != WAIT_FRAG_ACK) {
338 wpa_printf(MSG_INFO, "EAP-TNC: Invalid frame (empty)");
339 return true;
340 }
341
342 if (len == 0)
343 return false; /* Fragment ACK does not include flags */
344
345 if ((*pos & EAP_TNC_VERSION_MASK) != EAP_TNC_VERSION) {
346 wpa_printf(MSG_DEBUG, "EAP-TNC: Unsupported version %d",
347 *pos & EAP_TNC_VERSION_MASK);
348 return true;
349 }
350
351 if (*pos & EAP_TNC_FLAGS_START) {
352 wpa_printf(MSG_DEBUG, "EAP-TNC: Peer used Start flag");
353 return true;
354 }
355
356 return false;
357 }
358
359
tncs_process(struct eap_tnc_data * data,struct wpabuf * inbuf)360 static void tncs_process(struct eap_tnc_data *data, struct wpabuf *inbuf)
361 {
362 enum tncs_process_res res;
363
364 res = tncs_process_if_tnccs(data->tncs, wpabuf_head(inbuf),
365 wpabuf_len(inbuf));
366 switch (res) {
367 case TNCCS_RECOMMENDATION_ALLOW:
368 wpa_printf(MSG_DEBUG, "EAP-TNC: TNCS allowed access");
369 eap_tnc_set_state(data, RECOMMENDATION);
370 data->recommendation = ALLOW;
371 break;
372 case TNCCS_RECOMMENDATION_NO_RECOMMENDATION:
373 wpa_printf(MSG_DEBUG, "EAP-TNC: TNCS has no recommendation");
374 eap_tnc_set_state(data, RECOMMENDATION);
375 data->recommendation = NO_RECOMMENDATION;
376 break;
377 case TNCCS_RECOMMENDATION_ISOLATE:
378 wpa_printf(MSG_DEBUG, "EAP-TNC: TNCS requested isolation");
379 eap_tnc_set_state(data, RECOMMENDATION);
380 data->recommendation = ISOLATE;
381 break;
382 case TNCCS_RECOMMENDATION_NO_ACCESS:
383 wpa_printf(MSG_DEBUG, "EAP-TNC: TNCS rejected access");
384 eap_tnc_set_state(data, RECOMMENDATION);
385 data->recommendation = NO_ACCESS;
386 break;
387 case TNCCS_PROCESS_ERROR:
388 wpa_printf(MSG_DEBUG, "EAP-TNC: TNCS processing error");
389 eap_tnc_set_state(data, FAIL);
390 break;
391 default:
392 break;
393 }
394 }
395
396
eap_tnc_process_cont(struct eap_tnc_data * data,const u8 * buf,size_t len)397 static int eap_tnc_process_cont(struct eap_tnc_data *data,
398 const u8 *buf, size_t len)
399 {
400 /* Process continuation of a pending message */
401 if (len > wpabuf_tailroom(data->in_buf)) {
402 wpa_printf(MSG_DEBUG, "EAP-TNC: Fragment overflow");
403 eap_tnc_set_state(data, FAIL);
404 return -1;
405 }
406
407 wpabuf_put_data(data->in_buf, buf, len);
408 wpa_printf(MSG_DEBUG, "EAP-TNC: Received %lu bytes, waiting for %lu "
409 "bytes more", (unsigned long) len,
410 (unsigned long) wpabuf_tailroom(data->in_buf));
411
412 return 0;
413 }
414
415
eap_tnc_process_fragment(struct eap_tnc_data * data,u8 flags,u32 message_length,const u8 * buf,size_t len)416 static int eap_tnc_process_fragment(struct eap_tnc_data *data,
417 u8 flags, u32 message_length,
418 const u8 *buf, size_t len)
419 {
420 /* Process a fragment that is not the last one of the message */
421 if (data->in_buf == NULL && !(flags & EAP_TNC_FLAGS_LENGTH_INCLUDED)) {
422 wpa_printf(MSG_DEBUG, "EAP-TNC: No Message Length field in a "
423 "fragmented packet");
424 return -1;
425 }
426
427 if (data->in_buf == NULL) {
428 /* First fragment of the message */
429 data->in_buf = wpabuf_alloc(message_length);
430 if (data->in_buf == NULL) {
431 wpa_printf(MSG_DEBUG, "EAP-TNC: No memory for "
432 "message");
433 return -1;
434 }
435 wpabuf_put_data(data->in_buf, buf, len);
436 wpa_printf(MSG_DEBUG, "EAP-TNC: Received %lu bytes in first "
437 "fragment, waiting for %lu bytes more",
438 (unsigned long) len,
439 (unsigned long) wpabuf_tailroom(data->in_buf));
440 }
441
442 return 0;
443 }
444
445
eap_tnc_process(struct eap_sm * sm,void * priv,struct wpabuf * respData)446 static void eap_tnc_process(struct eap_sm *sm, void *priv,
447 struct wpabuf *respData)
448 {
449 struct eap_tnc_data *data = priv;
450 const u8 *pos, *end;
451 size_t len;
452 u8 flags;
453 u32 message_length = 0;
454 struct wpabuf tmpbuf;
455
456 pos = eap_hdr_validate(EAP_VENDOR_IETF, EAP_TYPE_TNC, respData, &len);
457 if (pos == NULL)
458 return; /* Should not happen; message already verified */
459
460 end = pos + len;
461
462 if (len == 1 && (data->state == DONE || data->state == FAIL)) {
463 wpa_printf(MSG_DEBUG, "EAP-TNC: Peer acknowledged the last "
464 "message");
465 return;
466 }
467
468 if (len == 0) {
469 /* fragment ack */
470 flags = 0;
471 } else
472 flags = *pos++;
473
474 if (flags & EAP_TNC_FLAGS_LENGTH_INCLUDED) {
475 if (end - pos < 4) {
476 wpa_printf(MSG_DEBUG, "EAP-TNC: Message underflow");
477 eap_tnc_set_state(data, FAIL);
478 return;
479 }
480 message_length = WPA_GET_BE32(pos);
481 pos += 4;
482
483 if (message_length < (u32) (end - pos) ||
484 message_length > 75000) {
485 wpa_printf(MSG_DEBUG, "EAP-TNC: Invalid Message "
486 "Length (%d; %ld remaining in this msg)",
487 message_length, (long) (end - pos));
488 eap_tnc_set_state(data, FAIL);
489 return;
490 }
491 }
492 wpa_printf(MSG_DEBUG, "EAP-TNC: Received packet: Flags 0x%x "
493 "Message Length %u", flags, message_length);
494
495 if (data->state == WAIT_FRAG_ACK) {
496 if (len > 1) {
497 wpa_printf(MSG_DEBUG, "EAP-TNC: Unexpected payload "
498 "in WAIT_FRAG_ACK state");
499 eap_tnc_set_state(data, FAIL);
500 return;
501 }
502 wpa_printf(MSG_DEBUG, "EAP-TNC: Fragment acknowledged");
503 eap_tnc_set_state(data, CONTINUE);
504 return;
505 }
506
507 if (data->in_buf && eap_tnc_process_cont(data, pos, end - pos) < 0) {
508 eap_tnc_set_state(data, FAIL);
509 return;
510 }
511
512 if (flags & EAP_TNC_FLAGS_MORE_FRAGMENTS) {
513 if (eap_tnc_process_fragment(data, flags, message_length,
514 pos, end - pos) < 0)
515 eap_tnc_set_state(data, FAIL);
516 else
517 eap_tnc_set_state(data, FRAG_ACK);
518 return;
519 } else if (data->state == FRAG_ACK) {
520 wpa_printf(MSG_DEBUG, "EAP-TNC: All fragments received");
521 eap_tnc_set_state(data, CONTINUE);
522 }
523
524 if (data->in_buf == NULL) {
525 /* Wrap unfragmented messages as wpabuf without extra copy */
526 wpabuf_set(&tmpbuf, pos, end - pos);
527 data->in_buf = &tmpbuf;
528 }
529
530 wpa_hexdump_ascii(MSG_MSGDUMP, "EAP-TNC: Received payload",
531 wpabuf_head(data->in_buf), wpabuf_len(data->in_buf));
532 tncs_process(data, data->in_buf);
533
534 if (data->in_buf != &tmpbuf)
535 wpabuf_free(data->in_buf);
536 data->in_buf = NULL;
537 }
538
539
eap_tnc_isDone(struct eap_sm * sm,void * priv)540 static bool eap_tnc_isDone(struct eap_sm *sm, void *priv)
541 {
542 struct eap_tnc_data *data = priv;
543 return data->state == DONE || data->state == FAIL;
544 }
545
546
eap_tnc_isSuccess(struct eap_sm * sm,void * priv)547 static bool eap_tnc_isSuccess(struct eap_sm *sm, void *priv)
548 {
549 struct eap_tnc_data *data = priv;
550 return data->state == DONE;
551 }
552
553
eap_server_tnc_register(void)554 int eap_server_tnc_register(void)
555 {
556 struct eap_method *eap;
557
558 eap = eap_server_method_alloc(EAP_SERVER_METHOD_INTERFACE_VERSION,
559 EAP_VENDOR_IETF, EAP_TYPE_TNC, "TNC");
560 if (eap == NULL)
561 return -1;
562
563 eap->init = eap_tnc_init;
564 eap->reset = eap_tnc_reset;
565 eap->buildReq = eap_tnc_buildReq;
566 eap->check = eap_tnc_check;
567 eap->process = eap_tnc_process;
568 eap->isDone = eap_tnc_isDone;
569 eap->isSuccess = eap_tnc_isSuccess;
570
571 return eap_server_method_register(eap);
572 }
573