1/*
2 * EAP peer method: EAP-TNC (Trusted Network Connect)
3 * Copyright (c) 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 "eap_i.h"
13#include "tncc.h"
14
15
16struct eap_tnc_data {
17	enum { WAIT_START, PROC_MSG, WAIT_FRAG_ACK, DONE, FAIL } state;
18	struct tncc_data *tncc;
19	struct wpabuf *in_buf;
20	struct wpabuf *out_buf;
21	size_t out_used;
22	size_t fragment_size;
23};
24
25
26/* EAP-TNC Flags */
27#define EAP_TNC_FLAGS_LENGTH_INCLUDED 0x80
28#define EAP_TNC_FLAGS_MORE_FRAGMENTS 0x40
29#define EAP_TNC_FLAGS_START 0x20
30#define EAP_TNC_VERSION_MASK 0x07
31
32#define EAP_TNC_VERSION 1
33
34
35static void * eap_tnc_init(struct eap_sm *sm)
36{
37	struct eap_tnc_data *data;
38
39	data = os_zalloc(sizeof(*data));
40	if (data == NULL)
41		return NULL;
42	data->state = WAIT_START;
43	data->fragment_size = 1300;
44	data->tncc = tncc_init();
45	if (data->tncc == NULL) {
46		os_free(data);
47		return NULL;
48	}
49
50	return data;
51}
52
53
54static void eap_tnc_deinit(struct eap_sm *sm, void *priv)
55{
56	struct eap_tnc_data *data = priv;
57
58	wpabuf_free(data->in_buf);
59	wpabuf_free(data->out_buf);
60	tncc_deinit(data->tncc);
61	os_free(data);
62}
63
64
65static struct wpabuf * eap_tnc_build_frag_ack(u8 id, u8 code)
66{
67	struct wpabuf *msg;
68
69	msg = eap_msg_alloc(EAP_VENDOR_IETF, EAP_TYPE_TNC, 1, code, id);
70	if (msg == NULL) {
71		wpa_printf(MSG_ERROR, "EAP-TNC: Failed to allocate memory "
72			   "for fragment ack");
73		return NULL;
74	}
75	wpabuf_put_u8(msg, EAP_TNC_VERSION); /* Flags */
76
77	wpa_printf(MSG_DEBUG, "EAP-TNC: Send fragment ack");
78
79	return msg;
80}
81
82
83static struct wpabuf * eap_tnc_build_msg(struct eap_tnc_data *data,
84					 struct eap_method_ret *ret, u8 id)
85{
86	struct wpabuf *resp;
87	u8 flags;
88	size_t send_len, plen;
89
90	ret->ignore = FALSE;
91	wpa_printf(MSG_DEBUG, "EAP-TNC: Generating Response");
92	ret->allowNotifications = TRUE;
93
94	flags = EAP_TNC_VERSION;
95	send_len = wpabuf_len(data->out_buf) - data->out_used;
96	if (1 + send_len > data->fragment_size) {
97		send_len = data->fragment_size - 1;
98		flags |= EAP_TNC_FLAGS_MORE_FRAGMENTS;
99		if (data->out_used == 0) {
100			flags |= EAP_TNC_FLAGS_LENGTH_INCLUDED;
101			send_len -= 4;
102		}
103	}
104
105	plen = 1 + send_len;
106	if (flags & EAP_TNC_FLAGS_LENGTH_INCLUDED)
107		plen += 4;
108	resp = eap_msg_alloc(EAP_VENDOR_IETF, EAP_TYPE_TNC, plen,
109			     EAP_CODE_RESPONSE, id);
110	if (resp == NULL)
111		return NULL;
112
113	wpabuf_put_u8(resp, flags); /* Flags */
114	if (flags & EAP_TNC_FLAGS_LENGTH_INCLUDED)
115		wpabuf_put_be32(resp, wpabuf_len(data->out_buf));
116
117	wpabuf_put_data(resp, wpabuf_head_u8(data->out_buf) + data->out_used,
118			send_len);
119	data->out_used += send_len;
120
121	ret->methodState = METHOD_MAY_CONT;
122	ret->decision = DECISION_FAIL;
123
124	if (data->out_used == wpabuf_len(data->out_buf)) {
125		wpa_printf(MSG_DEBUG, "EAP-TNC: Sending out %lu bytes "
126			   "(message sent completely)",
127			   (unsigned long) send_len);
128		wpabuf_free(data->out_buf);
129		data->out_buf = NULL;
130		data->out_used = 0;
131	} else {
132		wpa_printf(MSG_DEBUG, "EAP-TNC: Sending out %lu bytes "
133			   "(%lu more to send)", (unsigned long) send_len,
134			   (unsigned long) wpabuf_len(data->out_buf) -
135			   data->out_used);
136		data->state = WAIT_FRAG_ACK;
137	}
138
139	return resp;
140}
141
142
143static int eap_tnc_process_cont(struct eap_tnc_data *data,
144				const u8 *buf, size_t len)
145{
146	/* Process continuation of a pending message */
147	if (len > wpabuf_tailroom(data->in_buf)) {
148		wpa_printf(MSG_DEBUG, "EAP-TNC: Fragment overflow");
149		data->state = FAIL;
150		return -1;
151	}
152
153	wpabuf_put_data(data->in_buf, buf, len);
154	wpa_printf(MSG_DEBUG, "EAP-TNC: Received %lu bytes, waiting for "
155		   "%lu bytes more", (unsigned long) len,
156		   (unsigned long) wpabuf_tailroom(data->in_buf));
157
158	return 0;
159}
160
161
162static struct wpabuf * eap_tnc_process_fragment(struct eap_tnc_data *data,
163						struct eap_method_ret *ret,
164						u8 id, u8 flags,
165						u32 message_length,
166						const u8 *buf, size_t len)
167{
168	/* Process a fragment that is not the last one of the message */
169	if (data->in_buf == NULL && !(flags & EAP_TNC_FLAGS_LENGTH_INCLUDED)) {
170		wpa_printf(MSG_DEBUG, "EAP-TNC: No Message Length field in a "
171			   "fragmented packet");
172		ret->ignore = TRUE;
173		return NULL;
174	}
175
176	if (data->in_buf == NULL) {
177		/* First fragment of the message */
178		data->in_buf = wpabuf_alloc(message_length);
179		if (data->in_buf == NULL) {
180			wpa_printf(MSG_DEBUG, "EAP-TNC: No memory for "
181				   "message");
182			ret->ignore = TRUE;
183			return NULL;
184		}
185		wpabuf_put_data(data->in_buf, buf, len);
186		wpa_printf(MSG_DEBUG, "EAP-TNC: Received %lu bytes in first "
187			   "fragment, waiting for %lu bytes more",
188			   (unsigned long) len,
189			   (unsigned long) wpabuf_tailroom(data->in_buf));
190	}
191
192	return eap_tnc_build_frag_ack(id, EAP_CODE_RESPONSE);
193}
194
195
196static struct wpabuf * eap_tnc_process(struct eap_sm *sm, void *priv,
197				       struct eap_method_ret *ret,
198				       const struct wpabuf *reqData)
199{
200	struct eap_tnc_data *data = priv;
201	struct wpabuf *resp;
202	const u8 *pos, *end;
203	u8 *rpos, *rpos1;
204	size_t len, rlen;
205	size_t imc_len;
206	char *start_buf, *end_buf;
207	size_t start_len, end_len;
208	int tncs_done = 0;
209	u8 flags, id;
210	u32 message_length = 0;
211	struct wpabuf tmpbuf;
212
213	pos = eap_hdr_validate(EAP_VENDOR_IETF, EAP_TYPE_TNC, reqData, &len);
214	if (pos == NULL) {
215		wpa_printf(MSG_INFO, "EAP-TNC: Invalid frame (pos=%p len=%lu)",
216			   pos, (unsigned long) len);
217		ret->ignore = TRUE;
218		return NULL;
219	}
220
221	id = eap_get_id(reqData);
222
223	end = pos + len;
224
225	if (len == 0)
226		flags = 0; /* fragment ack */
227	else
228		flags = *pos++;
229
230	if (len > 0 && (flags & EAP_TNC_VERSION_MASK) != EAP_TNC_VERSION) {
231		wpa_printf(MSG_DEBUG, "EAP-TNC: Unsupported version %d",
232			   flags & EAP_TNC_VERSION_MASK);
233		ret->ignore = TRUE;
234		return NULL;
235	}
236
237	if (flags & EAP_TNC_FLAGS_LENGTH_INCLUDED) {
238		if (end - pos < 4) {
239			wpa_printf(MSG_DEBUG, "EAP-TNC: Message underflow");
240			ret->ignore = TRUE;
241			return NULL;
242		}
243		message_length = WPA_GET_BE32(pos);
244		pos += 4;
245
246		if (message_length < (u32) (end - pos) ||
247		    message_length > 75000) {
248			wpa_printf(MSG_DEBUG, "EAP-TNC: Invalid Message "
249				   "Length (%d; %ld remaining in this msg)",
250				   message_length, (long) (end - pos));
251			ret->ignore = TRUE;
252			return NULL;
253		}
254	}
255
256	wpa_printf(MSG_DEBUG, "EAP-TNC: Received packet: Flags 0x%x "
257		   "Message Length %u", flags, message_length);
258
259	if (data->state == WAIT_FRAG_ACK) {
260		if (len > 1) {
261			wpa_printf(MSG_DEBUG, "EAP-TNC: Unexpected payload in "
262				   "WAIT_FRAG_ACK state");
263			ret->ignore = TRUE;
264			return NULL;
265		}
266		wpa_printf(MSG_DEBUG, "EAP-TNC: Fragment acknowledged");
267		data->state = PROC_MSG;
268		return eap_tnc_build_msg(data, ret, id);
269	}
270
271	if (data->in_buf && eap_tnc_process_cont(data, pos, end - pos) < 0) {
272		ret->ignore = TRUE;
273		return NULL;
274	}
275
276	if (flags & EAP_TNC_FLAGS_MORE_FRAGMENTS) {
277		return eap_tnc_process_fragment(data, ret, id, flags,
278						message_length, pos,
279						end - pos);
280	}
281
282	if (data->in_buf == NULL) {
283		/* Wrap unfragmented messages as wpabuf without extra copy */
284		wpabuf_set(&tmpbuf, pos, end - pos);
285		data->in_buf = &tmpbuf;
286	}
287
288	if (data->state == WAIT_START) {
289		if (!(flags & EAP_TNC_FLAGS_START)) {
290			wpa_printf(MSG_DEBUG, "EAP-TNC: Server did not use "
291				   "start flag in the first message");
292			ret->ignore = TRUE;
293			goto fail;
294		}
295
296		tncc_init_connection(data->tncc);
297
298		data->state = PROC_MSG;
299	} else {
300		enum tncc_process_res res;
301
302		if (flags & EAP_TNC_FLAGS_START) {
303			wpa_printf(MSG_DEBUG, "EAP-TNC: Server used start "
304				   "flag again");
305			ret->ignore = TRUE;
306			goto fail;
307		}
308
309		res = tncc_process_if_tnccs(data->tncc,
310					    wpabuf_head(data->in_buf),
311					    wpabuf_len(data->in_buf));
312		switch (res) {
313		case TNCCS_PROCESS_ERROR:
314			ret->ignore = TRUE;
315			goto fail;
316		case TNCCS_PROCESS_OK_NO_RECOMMENDATION:
317		case TNCCS_RECOMMENDATION_ERROR:
318			wpa_printf(MSG_DEBUG, "EAP-TNC: No "
319				   "TNCCS-Recommendation received");
320			break;
321		case TNCCS_RECOMMENDATION_ALLOW:
322			wpa_msg(sm->msg_ctx, MSG_INFO,
323				"TNC: Recommendation = allow");
324			tncs_done = 1;
325			break;
326		case TNCCS_RECOMMENDATION_NONE:
327			wpa_msg(sm->msg_ctx, MSG_INFO,
328				"TNC: Recommendation = none");
329			tncs_done = 1;
330			break;
331		case TNCCS_RECOMMENDATION_ISOLATE:
332			wpa_msg(sm->msg_ctx, MSG_INFO,
333				"TNC: Recommendation = isolate");
334			tncs_done = 1;
335			break;
336		}
337	}
338
339	if (data->in_buf != &tmpbuf)
340		wpabuf_free(data->in_buf);
341	data->in_buf = NULL;
342
343	ret->ignore = FALSE;
344	ret->methodState = METHOD_MAY_CONT;
345	ret->decision = DECISION_UNCOND_SUCC;
346	ret->allowNotifications = TRUE;
347
348	if (data->out_buf) {
349		data->state = PROC_MSG;
350		return eap_tnc_build_msg(data, ret, id);
351	}
352
353	if (tncs_done) {
354		resp = eap_msg_alloc(EAP_VENDOR_IETF, EAP_TYPE_TNC, 1,
355				     EAP_CODE_RESPONSE, eap_get_id(reqData));
356		if (resp == NULL)
357			return NULL;
358
359		wpabuf_put_u8(resp, EAP_TNC_VERSION);
360		wpa_printf(MSG_DEBUG, "EAP-TNC: TNCS done - reply with an "
361			   "empty ACK message");
362		return resp;
363	}
364
365	imc_len = tncc_total_send_len(data->tncc);
366
367	start_buf = tncc_if_tnccs_start(data->tncc);
368	if (start_buf == NULL)
369		return NULL;
370	start_len = os_strlen(start_buf);
371	end_buf = tncc_if_tnccs_end();
372	if (end_buf == NULL) {
373		os_free(start_buf);
374		return NULL;
375	}
376	end_len = os_strlen(end_buf);
377
378	rlen = start_len + imc_len + end_len;
379	resp = wpabuf_alloc(rlen);
380	if (resp == NULL) {
381		os_free(start_buf);
382		os_free(end_buf);
383		return NULL;
384	}
385
386	wpabuf_put_data(resp, start_buf, start_len);
387	os_free(start_buf);
388
389	rpos1 = wpabuf_put(resp, 0);
390	rpos = tncc_copy_send_buf(data->tncc, rpos1);
391	wpabuf_put(resp, rpos - rpos1);
392
393	wpabuf_put_data(resp, end_buf, end_len);
394	os_free(end_buf);
395
396	wpa_hexdump_ascii(MSG_MSGDUMP, "EAP-TNC: Response",
397			  wpabuf_head(resp), wpabuf_len(resp));
398
399	data->out_buf = resp;
400	data->state = PROC_MSG;
401	return eap_tnc_build_msg(data, ret, id);
402
403fail:
404	if (data->in_buf == &tmpbuf)
405		data->in_buf = NULL;
406	return NULL;
407}
408
409
410int eap_peer_tnc_register(void)
411{
412	struct eap_method *eap;
413	int ret;
414
415	eap = eap_peer_method_alloc(EAP_PEER_METHOD_INTERFACE_VERSION,
416				    EAP_VENDOR_IETF, EAP_TYPE_TNC, "TNC");
417	if (eap == NULL)
418		return -1;
419
420	eap->init = eap_tnc_init;
421	eap->deinit = eap_tnc_deinit;
422	eap->process = eap_tnc_process;
423
424	ret = eap_peer_method_register(eap);
425	if (ret)
426		eap_peer_method_free(eap);
427	return ret;
428}
429