1/*
2 * EAP peer method: EAP-TNC (Trusted Network Connect)
3 * Copyright (c) 2007, Jouni Malinen <j@w1.fi>
4 *
5 * This program is free software; you can redistribute it and/or modify
6 * it under the terms of the GNU General Public License version 2 as
7 * published by the Free Software Foundation.
8 *
9 * Alternatively, this software may be distributed under the terms of BSD
10 * license.
11 *
12 * See README and COPYING for more details.
13 */
14
15#include "includes.h"
16
17#include "common.h"
18#include "base64.h"
19#include "eap_i.h"
20#include "tncc.h"
21
22
23struct eap_tnc_data {
24	enum { WAIT_START, PROC_MSG, WAIT_FRAG_ACK, DONE, FAIL } state;
25	struct tncc_data *tncc;
26	struct wpabuf *in_buf;
27	struct wpabuf *out_buf;
28	size_t out_used;
29	size_t fragment_size;
30};
31
32
33/* EAP-TNC Flags */
34#define EAP_TNC_FLAGS_LENGTH_INCLUDED 0x80
35#define EAP_TNC_FLAGS_MORE_FRAGMENTS 0x40
36#define EAP_TNC_FLAGS_START 0x20
37#define EAP_TNC_VERSION_MASK 0x07
38
39#define EAP_TNC_VERSION 1
40
41
42static void * eap_tnc_init(struct eap_sm *sm)
43{
44	struct eap_tnc_data *data;
45
46	data = os_zalloc(sizeof(*data));
47	if (data == NULL)
48		return NULL;
49	data->state = WAIT_START;
50	data->fragment_size = 1300;
51	data->tncc = tncc_init();
52	if (data->tncc == NULL) {
53		os_free(data);
54		return NULL;
55	}
56
57	return data;
58}
59
60
61static void eap_tnc_deinit(struct eap_sm *sm, void *priv)
62{
63	struct eap_tnc_data *data = priv;
64
65	wpabuf_free(data->in_buf);
66	wpabuf_free(data->out_buf);
67	tncc_deinit(data->tncc);
68	os_free(data);
69}
70
71
72static struct wpabuf * eap_tnc_build_frag_ack(u8 id, u8 code)
73{
74	struct wpabuf *msg;
75
76	msg = eap_msg_alloc(EAP_VENDOR_IETF, EAP_TYPE_TNC, 1, code, id);
77	if (msg == NULL) {
78		wpa_printf(MSG_ERROR, "EAP-TNC: Failed to allocate memory "
79			   "for fragment ack");
80		return NULL;
81	}
82	wpabuf_put_u8(msg, EAP_TNC_VERSION); /* Flags */
83
84	wpa_printf(MSG_DEBUG, "EAP-TNC: Send fragment ack");
85
86	return msg;
87}
88
89
90static struct wpabuf * eap_tnc_build_msg(struct eap_tnc_data *data,
91					 struct eap_method_ret *ret, u8 id)
92{
93	struct wpabuf *resp;
94	u8 flags;
95	size_t send_len, plen;
96
97	ret->ignore = FALSE;
98	wpa_printf(MSG_DEBUG, "EAP-TNC: Generating Response");
99	ret->allowNotifications = TRUE;
100
101	flags = EAP_TNC_VERSION;
102	send_len = wpabuf_len(data->out_buf) - data->out_used;
103	if (1 + send_len > data->fragment_size) {
104		send_len = data->fragment_size - 1;
105		flags |= EAP_TNC_FLAGS_MORE_FRAGMENTS;
106		if (data->out_used == 0) {
107			flags |= EAP_TNC_FLAGS_LENGTH_INCLUDED;
108			send_len -= 4;
109		}
110	}
111
112	plen = 1 + send_len;
113	if (flags & EAP_TNC_FLAGS_LENGTH_INCLUDED)
114		plen += 4;
115	resp = eap_msg_alloc(EAP_VENDOR_IETF, EAP_TYPE_TNC, plen,
116			     EAP_CODE_RESPONSE, id);
117	if (resp == NULL)
118		return NULL;
119
120	wpabuf_put_u8(resp, flags); /* Flags */
121	if (flags & EAP_TNC_FLAGS_LENGTH_INCLUDED)
122		wpabuf_put_be32(resp, wpabuf_len(data->out_buf));
123
124	wpabuf_put_data(resp, wpabuf_head_u8(data->out_buf) + data->out_used,
125			send_len);
126	data->out_used += send_len;
127
128	ret->methodState = METHOD_MAY_CONT;
129	ret->decision = DECISION_FAIL;
130
131	if (data->out_used == wpabuf_len(data->out_buf)) {
132		wpa_printf(MSG_DEBUG, "EAP-TNC: Sending out %lu bytes "
133			   "(message sent completely)",
134			   (unsigned long) send_len);
135		wpabuf_free(data->out_buf);
136		data->out_buf = NULL;
137		data->out_used = 0;
138	} else {
139		wpa_printf(MSG_DEBUG, "EAP-TNC: Sending out %lu bytes "
140			   "(%lu more to send)", (unsigned long) send_len,
141			   (unsigned long) wpabuf_len(data->out_buf) -
142			   data->out_used);
143		data->state = WAIT_FRAG_ACK;
144	}
145
146	return resp;
147}
148
149
150static int eap_tnc_process_cont(struct eap_tnc_data *data,
151				const u8 *buf, size_t len)
152{
153	/* Process continuation of a pending message */
154	if (len > wpabuf_tailroom(data->in_buf)) {
155		wpa_printf(MSG_DEBUG, "EAP-TNC: Fragment overflow");
156		data->state = FAIL;
157		return -1;
158	}
159
160	wpabuf_put_data(data->in_buf, buf, len);
161	wpa_printf(MSG_DEBUG, "EAP-TNC: Received %lu bytes, waiting for "
162		   "%lu bytes more", (unsigned long) len,
163		   (unsigned long) wpabuf_tailroom(data->in_buf));
164
165	return 0;
166}
167
168
169static struct wpabuf * eap_tnc_process_fragment(struct eap_tnc_data *data,
170						struct eap_method_ret *ret,
171						u8 id, u8 flags,
172						u32 message_length,
173						const u8 *buf, size_t len)
174{
175	/* Process a fragment that is not the last one of the message */
176	if (data->in_buf == NULL && !(flags & EAP_TNC_FLAGS_LENGTH_INCLUDED)) {
177		wpa_printf(MSG_DEBUG, "EAP-TNC: No Message Length field in a "
178			   "fragmented packet");
179		ret->ignore = TRUE;
180		return NULL;
181	}
182
183	if (data->in_buf == NULL) {
184		/* First fragment of the message */
185		data->in_buf = wpabuf_alloc(message_length);
186		if (data->in_buf == NULL) {
187			wpa_printf(MSG_DEBUG, "EAP-TNC: No memory for "
188				   "message");
189			ret->ignore = TRUE;
190			return NULL;
191		}
192		wpabuf_put_data(data->in_buf, buf, len);
193		wpa_printf(MSG_DEBUG, "EAP-TNC: Received %lu bytes in first "
194			   "fragment, waiting for %lu bytes more",
195			   (unsigned long) len,
196			   (unsigned long) wpabuf_tailroom(data->in_buf));
197	}
198
199	return eap_tnc_build_frag_ack(id, EAP_CODE_RESPONSE);
200}
201
202
203static struct wpabuf * eap_tnc_process(struct eap_sm *sm, void *priv,
204				       struct eap_method_ret *ret,
205				       const struct wpabuf *reqData)
206{
207	struct eap_tnc_data *data = priv;
208	struct wpabuf *resp;
209	const u8 *pos, *end;
210	u8 *rpos, *rpos1;
211	size_t len, rlen;
212	size_t imc_len;
213	char *start_buf, *end_buf;
214	size_t start_len, end_len;
215	int tncs_done = 0;
216	u8 flags, id;
217	u32 message_length = 0;
218	struct wpabuf tmpbuf;
219
220	pos = eap_hdr_validate(EAP_VENDOR_IETF, EAP_TYPE_TNC, reqData, &len);
221	if (pos == NULL) {
222		wpa_printf(MSG_INFO, "EAP-TNC: Invalid frame (pos=%p len=%lu)",
223			   pos, (unsigned long) len);
224		ret->ignore = TRUE;
225		return NULL;
226	}
227
228	id = eap_get_id(reqData);
229
230	end = pos + len;
231
232	if (len == 0)
233		flags = 0; /* fragment ack */
234	else
235		flags = *pos++;
236
237	if (len > 0 && (flags & EAP_TNC_VERSION_MASK) != EAP_TNC_VERSION) {
238		wpa_printf(MSG_DEBUG, "EAP-TNC: Unsupported version %d",
239			   flags & EAP_TNC_VERSION_MASK);
240		ret->ignore = TRUE;
241		return NULL;
242	}
243
244	if (flags & EAP_TNC_FLAGS_LENGTH_INCLUDED) {
245		if (end - pos < 4) {
246			wpa_printf(MSG_DEBUG, "EAP-TNC: Message underflow");
247			ret->ignore = TRUE;
248			return NULL;
249		}
250		message_length = WPA_GET_BE32(pos);
251		pos += 4;
252
253		if (message_length < (u32) (end - pos)) {
254			wpa_printf(MSG_DEBUG, "EAP-TNC: Invalid Message "
255				   "Length (%d; %ld remaining in this msg)",
256				   message_length, (long) (end - pos));
257			ret->ignore = TRUE;
258			return NULL;
259		}
260	}
261
262	wpa_printf(MSG_DEBUG, "EAP-TNC: Received packet: Flags 0x%x "
263		   "Message Length %u", flags, message_length);
264
265	if (data->state == WAIT_FRAG_ACK) {
266		if (len > 1) {
267			wpa_printf(MSG_DEBUG, "EAP-TNC: Unexpected payload in "
268				   "WAIT_FRAG_ACK state");
269			ret->ignore = TRUE;
270			return NULL;
271		}
272		wpa_printf(MSG_DEBUG, "EAP-TNC: Fragment acknowledged");
273		data->state = PROC_MSG;
274		return eap_tnc_build_msg(data, ret, id);
275	}
276
277	if (data->in_buf && eap_tnc_process_cont(data, pos, end - pos) < 0) {
278		ret->ignore = TRUE;
279		return NULL;
280	}
281
282	if (flags & EAP_TNC_FLAGS_MORE_FRAGMENTS) {
283		return eap_tnc_process_fragment(data, ret, id, flags,
284						message_length, pos,
285						end - pos);
286	}
287
288	if (data->in_buf == NULL) {
289		/* Wrap unfragmented messages as wpabuf without extra copy */
290		wpabuf_set(&tmpbuf, pos, end - pos);
291		data->in_buf = &tmpbuf;
292	}
293
294	if (data->state == WAIT_START) {
295		if (!(flags & EAP_TNC_FLAGS_START)) {
296			wpa_printf(MSG_DEBUG, "EAP-TNC: Server did not use "
297				   "start flag in the first message");
298			ret->ignore = TRUE;
299			goto fail;
300		}
301
302		tncc_init_connection(data->tncc);
303
304		data->state = PROC_MSG;
305	} else {
306		enum tncc_process_res res;
307
308		if (flags & EAP_TNC_FLAGS_START) {
309			wpa_printf(MSG_DEBUG, "EAP-TNC: Server used start "
310				   "flag again");
311			ret->ignore = TRUE;
312			goto fail;
313		}
314
315		res = tncc_process_if_tnccs(data->tncc,
316					    wpabuf_head(data->in_buf),
317					    wpabuf_len(data->in_buf));
318		switch (res) {
319		case TNCCS_PROCESS_ERROR:
320			ret->ignore = TRUE;
321			goto fail;
322		case TNCCS_PROCESS_OK_NO_RECOMMENDATION:
323		case TNCCS_RECOMMENDATION_ERROR:
324			wpa_printf(MSG_DEBUG, "EAP-TNC: No "
325				   "TNCCS-Recommendation received");
326			break;
327		case TNCCS_RECOMMENDATION_ALLOW:
328			wpa_msg(sm->msg_ctx, MSG_INFO,
329				"TNC: Recommendation = allow");
330			tncs_done = 1;
331			break;
332		case TNCCS_RECOMMENDATION_NONE:
333			wpa_msg(sm->msg_ctx, MSG_INFO,
334				"TNC: Recommendation = none");
335			tncs_done = 1;
336			break;
337		case TNCCS_RECOMMENDATION_ISOLATE:
338			wpa_msg(sm->msg_ctx, MSG_INFO,
339				"TNC: Recommendation = isolate");
340			tncs_done = 1;
341			break;
342		}
343	}
344
345	if (data->in_buf != &tmpbuf)
346		wpabuf_free(data->in_buf);
347	data->in_buf = NULL;
348
349	ret->ignore = FALSE;
350	ret->methodState = METHOD_MAY_CONT;
351	ret->decision = DECISION_UNCOND_SUCC;
352	ret->allowNotifications = TRUE;
353
354	if (data->out_buf) {
355		data->state = PROC_MSG;
356		return eap_tnc_build_msg(data, ret, id);
357	}
358
359	if (tncs_done) {
360		resp = eap_msg_alloc(EAP_VENDOR_IETF, EAP_TYPE_TNC, 1,
361				     EAP_CODE_RESPONSE, eap_get_id(reqData));
362		if (resp == NULL)
363			return NULL;
364
365		wpabuf_put_u8(resp, EAP_TNC_VERSION);
366		wpa_printf(MSG_DEBUG, "EAP-TNC: TNCS done - reply with an "
367			   "empty ACK message");
368		return resp;
369	}
370
371	imc_len = tncc_total_send_len(data->tncc);
372
373	start_buf = tncc_if_tnccs_start(data->tncc);
374	if (start_buf == NULL)
375		return NULL;
376	start_len = os_strlen(start_buf);
377	end_buf = tncc_if_tnccs_end();
378	if (end_buf == NULL) {
379		os_free(start_buf);
380		return NULL;
381	}
382	end_len = os_strlen(end_buf);
383
384	rlen = start_len + imc_len + end_len;
385	resp = wpabuf_alloc(rlen);
386	if (resp == NULL) {
387		os_free(start_buf);
388		os_free(end_buf);
389		return NULL;
390	}
391
392	wpabuf_put_data(resp, start_buf, start_len);
393	os_free(start_buf);
394
395	rpos1 = wpabuf_put(resp, 0);
396	rpos = tncc_copy_send_buf(data->tncc, rpos1);
397	wpabuf_put(resp, rpos - rpos1);
398
399	wpabuf_put_data(resp, end_buf, end_len);
400	os_free(end_buf);
401
402	wpa_hexdump_ascii(MSG_MSGDUMP, "EAP-TNC: Response",
403			  wpabuf_head(resp), wpabuf_len(resp));
404
405	data->out_buf = resp;
406	data->state = PROC_MSG;
407	return eap_tnc_build_msg(data, ret, id);
408
409fail:
410	if (data->in_buf == &tmpbuf)
411		data->in_buf = NULL;
412	return NULL;
413}
414
415
416int eap_peer_tnc_register(void)
417{
418	struct eap_method *eap;
419	int ret;
420
421	eap = eap_peer_method_alloc(EAP_PEER_METHOD_INTERFACE_VERSION,
422				    EAP_VENDOR_IETF, EAP_TYPE_TNC, "TNC");
423	if (eap == NULL)
424		return -1;
425
426	eap->init = eap_tnc_init;
427	eap->deinit = eap_tnc_deinit;
428	eap->process = eap_tnc_process;
429
430	ret = eap_peer_method_register(eap);
431	if (ret)
432		eap_peer_method_free(eap);
433	return ret;
434}
435