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 
17 struct 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 
eap_tnc_init(struct eap_sm * sm)36 static 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 
eap_tnc_deinit(struct eap_sm * sm,void * priv)59 static 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 
eap_tnc_build_frag_ack(u8 id,u8 code)70 static 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 
eap_tnc_build_msg(struct eap_tnc_data * data,struct eap_method_ret * ret,u8 id)88 static 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 
eap_tnc_process_cont(struct eap_tnc_data * data,const u8 * buf,size_t len)148 static 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 
eap_tnc_process_fragment(struct eap_tnc_data * data,struct eap_method_ret * ret,u8 id,u8 flags,u32 message_length,const u8 * buf,size_t len)167 static 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 
eap_tnc_process(struct eap_sm * sm,void * priv,struct eap_method_ret * ret,const struct wpabuf * reqData)201 static 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 
403 fail:
404 	if (data->in_buf == &tmpbuf)
405 		data->in_buf = NULL;
406 	return NULL;
407 }
408 
409 
eap_peer_tnc_register(void)410 int 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