xref: /freebsd/contrib/wpa/src/eap_peer/eap_tnc.c (revision 7750ad47a9a7dbc83f87158464170c8640723293)
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 
23 struct 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 
42 static 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 
61 static 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 
72 static 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 
90 static 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 
150 static 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 
169 static 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 
203 static 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 
409 fail:
410 	if (data->in_buf == &tmpbuf)
411 		data->in_buf = NULL;
412 	return NULL;
413 }
414 
415 
416 int 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