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