eap_tnc.c revision 1f69aa52ea2e0a73ac502565df8c666ee49cab6a 
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 "eap_i.h"
19#include "tncc.h"
20
21
22struct eap_tnc_data {
23	enum { WAIT_START, PROC_MSG, WAIT_FRAG_ACK, DONE, FAIL } state;
24	struct tncc_data *tncc;
25	struct wpabuf *in_buf;
26	struct wpabuf *out_buf;
27	size_t out_used;
28	size_t fragment_size;
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
41static void * eap_tnc_init(struct eap_sm *sm)
42{
43	struct eap_tnc_data *data;
44
45	data = os_zalloc(sizeof(*data));
46	if (data == NULL)
47		return NULL;
48	data->state = WAIT_START;
49	data->fragment_size = 1300;
50	data->tncc = tncc_init();
51	if (data->tncc == NULL) {
52		os_free(data);
53		return NULL;
54	}
55
56	return data;
57}
58
59
60static void eap_tnc_deinit(struct eap_sm *sm, void *priv)
61{
62	struct eap_tnc_data *data = priv;
63
64	wpabuf_free(data->in_buf);
65	wpabuf_free(data->out_buf);
66	tncc_deinit(data->tncc);
67	os_free(data);
68}
69
70
71static struct wpabuf * eap_tnc_build_frag_ack(u8 id, u8 code)
72{
73	struct wpabuf *msg;
74
75	msg = eap_msg_alloc(EAP_VENDOR_IETF, EAP_TYPE_TNC, 1, code, id);
76	if (msg == NULL) {
77		wpa_printf(MSG_ERROR, "EAP-TNC: Failed to allocate memory "
78			   "for fragment ack");
79		return NULL;
80	}
81	wpabuf_put_u8(msg, EAP_TNC_VERSION); /* Flags */
82
83	wpa_printf(MSG_DEBUG, "EAP-TNC: Send fragment ack");
84
85	return msg;
86}
87
88
89static struct wpabuf * eap_tnc_build_msg(struct eap_tnc_data *data,
90					 struct eap_method_ret *ret, u8 id)
91{
92	struct wpabuf *resp;
93	u8 flags;
94	size_t send_len, plen;
95
96	ret->ignore = FALSE;
97	wpa_printf(MSG_DEBUG, "EAP-TNC: Generating Response");
98	ret->allowNotifications = TRUE;
99
100	flags = EAP_TNC_VERSION;
101	send_len = wpabuf_len(data->out_buf) - data->out_used;
102	if (1 + send_len > data->fragment_size) {
103		send_len = data->fragment_size - 1;
104		flags |= EAP_TNC_FLAGS_MORE_FRAGMENTS;
105		if (data->out_used == 0) {
106			flags |= EAP_TNC_FLAGS_LENGTH_INCLUDED;
107			send_len -= 4;
108		}
109	}
110
111	plen = 1 + send_len;
112	if (flags & EAP_TNC_FLAGS_LENGTH_INCLUDED)
113		plen += 4;
114	resp = eap_msg_alloc(EAP_VENDOR_IETF, EAP_TYPE_TNC, plen,
115			     EAP_CODE_RESPONSE, id);
116	if (resp == NULL)
117		return NULL;
118
119	wpabuf_put_u8(resp, flags); /* Flags */
120	if (flags & EAP_TNC_FLAGS_LENGTH_INCLUDED)
121		wpabuf_put_be32(resp, wpabuf_len(data->out_buf));
122
123	wpabuf_put_data(resp, wpabuf_head_u8(data->out_buf) + data->out_used,
124			send_len);
125	data->out_used += send_len;
126
127	ret->methodState = METHOD_MAY_CONT;
128	ret->decision = DECISION_FAIL;
129
130	if (data->out_used == wpabuf_len(data->out_buf)) {
131		wpa_printf(MSG_DEBUG, "EAP-TNC: Sending out %lu bytes "
132			   "(message sent completely)",
133			   (unsigned long) send_len);
134		wpabuf_free(data->out_buf);
135		data->out_buf = NULL;
136		data->out_used = 0;
137	} else {
138		wpa_printf(MSG_DEBUG, "EAP-TNC: Sending out %lu bytes "
139			   "(%lu more to send)", (unsigned long) send_len,
140			   (unsigned long) wpabuf_len(data->out_buf) -
141			   data->out_used);
142		data->state = WAIT_FRAG_ACK;
143	}
144
145	return resp;
146}
147
148
149static int eap_tnc_process_cont(struct eap_tnc_data *data,
150				const u8 *buf, size_t len)
151{
152	/* Process continuation of a pending message */
153	if (len > wpabuf_tailroom(data->in_buf)) {
154		wpa_printf(MSG_DEBUG, "EAP-TNC: Fragment overflow");
155		data->state = FAIL;
156		return -1;
157	}
158
159	wpabuf_put_data(data->in_buf, buf, len);
160	wpa_printf(MSG_DEBUG, "EAP-TNC: Received %lu bytes, waiting for "
161		   "%lu bytes more", (unsigned long) len,
162		   (unsigned long) wpabuf_tailroom(data->in_buf));
163
164	return 0;
165}
166
167
168static struct wpabuf * eap_tnc_process_fragment(struct eap_tnc_data *data,
169						struct eap_method_ret *ret,
170						u8 id, u8 flags,
171						u32 message_length,
172						const u8 *buf, size_t len)
173{
174	/* Process a fragment that is not the last one of the message */
175	if (data->in_buf == NULL && !(flags & EAP_TNC_FLAGS_LENGTH_INCLUDED)) {
176		wpa_printf(MSG_DEBUG, "EAP-TNC: No Message Length field in a "
177			   "fragmented packet");
178		ret->ignore = TRUE;
179		return NULL;
180	}
181
182	if (data->in_buf == NULL) {
183		/* First fragment of the message */
184		data->in_buf = wpabuf_alloc(message_length);
185		if (data->in_buf == NULL) {
186			wpa_printf(MSG_DEBUG, "EAP-TNC: No memory for "
187				   "message");
188			ret->ignore = TRUE;
189			return NULL;
190		}
191		wpabuf_put_data(data->in_buf, buf, len);
192		wpa_printf(MSG_DEBUG, "EAP-TNC: Received %lu bytes in first "
193			   "fragment, waiting for %lu bytes more",
194			   (unsigned long) len,
195			   (unsigned long) wpabuf_tailroom(data->in_buf));
196	}
197
198	return eap_tnc_build_frag_ack(id, EAP_CODE_RESPONSE);
199}
200
201
202static struct wpabuf * eap_tnc_process(struct eap_sm *sm, void *priv,
203				       struct eap_method_ret *ret,
204				       const struct wpabuf *reqData)
205{
206	struct eap_tnc_data *data = priv;
207	struct wpabuf *resp;
208	const u8 *pos, *end;
209	u8 *rpos, *rpos1;
210	size_t len, rlen;
211	size_t imc_len;
212	char *start_buf, *end_buf;
213	size_t start_len, end_len;
214	int tncs_done = 0;
215	u8 flags, id;
216	u32 message_length = 0;
217	struct wpabuf tmpbuf;
218
219	pos = eap_hdr_validate(EAP_VENDOR_IETF, EAP_TYPE_TNC, reqData, &len);
220	if (pos == NULL) {
221		wpa_printf(MSG_INFO, "EAP-TNC: Invalid frame (pos=%p len=%lu)",
222			   pos, (unsigned long) len);
223		ret->ignore = TRUE;
224		return NULL;
225	}
226
227	id = eap_get_id(reqData);
228
229	end = pos + len;
230
231	if (len == 0)
232		flags = 0; /* fragment ack */
233	else
234		flags = *pos++;
235
236	if (len > 0 && (flags & EAP_TNC_VERSION_MASK) != EAP_TNC_VERSION) {
237		wpa_printf(MSG_DEBUG, "EAP-TNC: Unsupported version %d",
238			   flags & EAP_TNC_VERSION_MASK);
239		ret->ignore = TRUE;
240		return NULL;
241	}
242
243	if (flags & EAP_TNC_FLAGS_LENGTH_INCLUDED) {
244		if (end - pos < 4) {
245			wpa_printf(MSG_DEBUG, "EAP-TNC: Message underflow");
246			ret->ignore = TRUE;
247			return NULL;
248		}
249		message_length = WPA_GET_BE32(pos);
250		pos += 4;
251
252		if (message_length < (u32) (end - pos)) {
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 (data->out_buf) {
354		data->state = PROC_MSG;
355		return eap_tnc_build_msg(data, ret, id);
356	}
357
358	if (tncs_done) {
359		resp = eap_msg_alloc(EAP_VENDOR_IETF, EAP_TYPE_TNC, 1,
360				     EAP_CODE_RESPONSE, eap_get_id(reqData));
361		if (resp == NULL)
362			return NULL;
363
364		wpabuf_put_u8(resp, EAP_TNC_VERSION);
365		wpa_printf(MSG_DEBUG, "EAP-TNC: TNCS done - reply with an "
366			   "empty ACK message");
367		return resp;
368	}
369
370	imc_len = tncc_total_send_len(data->tncc);
371
372	start_buf = tncc_if_tnccs_start(data->tncc);
373	if (start_buf == NULL)
374		return NULL;
375	start_len = os_strlen(start_buf);
376	end_buf = tncc_if_tnccs_end();
377	if (end_buf == NULL) {
378		os_free(start_buf);
379		return NULL;
380	}
381	end_len = os_strlen(end_buf);
382
383	rlen = start_len + imc_len + end_len;
384	resp = wpabuf_alloc(rlen);
385	if (resp == NULL) {
386		os_free(start_buf);
387		os_free(end_buf);
388		return NULL;
389	}
390
391	wpabuf_put_data(resp, start_buf, start_len);
392	os_free(start_buf);
393
394	rpos1 = wpabuf_put(resp, 0);
395	rpos = tncc_copy_send_buf(data->tncc, rpos1);
396	wpabuf_put(resp, rpos - rpos1);
397
398	wpabuf_put_data(resp, end_buf, end_len);
399	os_free(end_buf);
400
401	wpa_hexdump_ascii(MSG_MSGDUMP, "EAP-TNC: Response",
402			  wpabuf_head(resp), wpabuf_len(resp));
403
404	data->out_buf = resp;
405	data->state = PROC_MSG;
406	return eap_tnc_build_msg(data, ret, id);
407
408fail:
409	if (data->in_buf == &tmpbuf)
410		data->in_buf = NULL;
411	return NULL;
412}
413
414
415int eap_peer_tnc_register(void)
416{
417	struct eap_method *eap;
418	int ret;
419
420	eap = eap_peer_method_alloc(EAP_PEER_METHOD_INTERFACE_VERSION,
421				    EAP_VENDOR_IETF, EAP_TYPE_TNC, "TNC");
422	if (eap == NULL)
423		return -1;
424
425	eap->init = eap_tnc_init;
426	eap->deinit = eap_tnc_deinit;
427	eap->process = eap_tnc_process;
428
429	ret = eap_peer_method_register(eap);
430	if (ret)
431		eap_peer_method_free(eap);
432	return ret;
433}
434