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