1 /*
2  * EAP peer method: LEAP
3  * Copyright (c) 2004-2007, 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 "crypto/ms_funcs.h"
13 #include "crypto/crypto.h"
14 #include "crypto/random.h"
15 #include "eap_i.h"
16 
17 #define LEAP_VERSION 1
18 #define LEAP_CHALLENGE_LEN 8
19 #define LEAP_RESPONSE_LEN 24
20 #define LEAP_KEY_LEN 16
21 
22 
23 struct eap_leap_data {
24 	enum {
25 		LEAP_WAIT_CHALLENGE,
26 		LEAP_WAIT_SUCCESS,
27 		LEAP_WAIT_RESPONSE,
28 		LEAP_DONE
29 	} state;
30 
31 	u8 peer_challenge[LEAP_CHALLENGE_LEN];
32 	u8 peer_response[LEAP_RESPONSE_LEN];
33 
34 	u8 ap_challenge[LEAP_CHALLENGE_LEN];
35 	u8 ap_response[LEAP_RESPONSE_LEN];
36 };
37 
38 
eap_leap_init(struct eap_sm * sm)39 static void * eap_leap_init(struct eap_sm *sm)
40 {
41 	struct eap_leap_data *data;
42 
43 	data = os_zalloc(sizeof(*data));
44 	if (data == NULL)
45 		return NULL;
46 	data->state = LEAP_WAIT_CHALLENGE;
47 
48 	sm->leap_done = false;
49 	return data;
50 }
51 
52 
eap_leap_deinit(struct eap_sm * sm,void * priv)53 static void eap_leap_deinit(struct eap_sm *sm, void *priv)
54 {
55 	os_free(priv);
56 }
57 
58 
eap_leap_process_request(struct eap_sm * sm,void * priv,struct eap_method_ret * ret,const struct wpabuf * reqData)59 static struct wpabuf * eap_leap_process_request(struct eap_sm *sm, void *priv,
60 						struct eap_method_ret *ret,
61 						const struct wpabuf *reqData)
62 {
63 	struct eap_leap_data *data = priv;
64 	struct wpabuf *resp;
65 	const u8 *pos, *challenge, *identity, *password;
66 	u8 challenge_len, *rpos;
67 	size_t identity_len, password_len, len;
68 	int pwhash;
69 
70 	wpa_printf(MSG_DEBUG, "EAP-LEAP: Processing EAP-Request");
71 
72 	identity = eap_get_config_identity(sm, &identity_len);
73 	password = eap_get_config_password2(sm, &password_len, &pwhash);
74 	if (identity == NULL || password == NULL)
75 		return NULL;
76 
77 	pos = eap_hdr_validate(EAP_VENDOR_IETF, EAP_TYPE_LEAP, reqData, &len);
78 	if (pos == NULL || len < 3) {
79 		wpa_printf(MSG_INFO, "EAP-LEAP: Invalid EAP-Request frame");
80 		ret->ignore = true;
81 		return NULL;
82 	}
83 
84 	if (*pos != LEAP_VERSION) {
85 		wpa_printf(MSG_WARNING, "EAP-LEAP: Unsupported LEAP version "
86 			   "%d", *pos);
87 		ret->ignore = true;
88 		return NULL;
89 	}
90 	pos++;
91 
92 	pos++; /* skip unused byte */
93 
94 	challenge_len = *pos++;
95 	if (challenge_len != LEAP_CHALLENGE_LEN || challenge_len > len - 3) {
96 		wpa_printf(MSG_INFO, "EAP-LEAP: Invalid challenge "
97 			   "(challenge_len=%d reqDataLen=%lu)",
98 			   challenge_len, (unsigned long) wpabuf_len(reqData));
99 		ret->ignore = true;
100 		return NULL;
101 	}
102 	challenge = pos;
103 	os_memcpy(data->peer_challenge, challenge, LEAP_CHALLENGE_LEN);
104 	wpa_hexdump(MSG_MSGDUMP, "EAP-LEAP: Challenge from AP",
105 		    challenge, LEAP_CHALLENGE_LEN);
106 
107 	wpa_printf(MSG_DEBUG, "EAP-LEAP: Generating Challenge Response");
108 
109 	resp = eap_msg_alloc(EAP_VENDOR_IETF, EAP_TYPE_LEAP,
110 			     3 + LEAP_RESPONSE_LEN + identity_len,
111 			     EAP_CODE_RESPONSE, eap_get_id(reqData));
112 	if (resp == NULL)
113 		return NULL;
114 	wpabuf_put_u8(resp, LEAP_VERSION);
115 	wpabuf_put_u8(resp, 0); /* unused */
116 	wpabuf_put_u8(resp, LEAP_RESPONSE_LEN);
117 	rpos = wpabuf_put(resp, LEAP_RESPONSE_LEN);
118 	if ((pwhash && challenge_response(challenge, password, rpos)) ||
119 	    (!pwhash &&
120 	     nt_challenge_response(challenge, password, password_len, rpos))) {
121 		wpa_printf(MSG_DEBUG, "EAP-LEAP: Failed to derive response");
122 		ret->ignore = true;
123 		wpabuf_free(resp);
124 		return NULL;
125 	}
126 	os_memcpy(data->peer_response, rpos, LEAP_RESPONSE_LEN);
127 	wpa_hexdump(MSG_MSGDUMP, "EAP-LEAP: Response",
128 		    rpos, LEAP_RESPONSE_LEN);
129 	wpabuf_put_data(resp, identity, identity_len);
130 
131 	data->state = LEAP_WAIT_SUCCESS;
132 
133 	return resp;
134 }
135 
136 
eap_leap_process_success(struct eap_sm * sm,void * priv,struct eap_method_ret * ret,const struct wpabuf * reqData)137 static struct wpabuf * eap_leap_process_success(struct eap_sm *sm, void *priv,
138 						struct eap_method_ret *ret,
139 						const struct wpabuf *reqData)
140 {
141 	struct eap_leap_data *data = priv;
142 	struct wpabuf *resp;
143 	u8 *pos;
144 	const u8 *identity;
145 	size_t identity_len;
146 
147 	wpa_printf(MSG_DEBUG, "EAP-LEAP: Processing EAP-Success");
148 
149 	identity = eap_get_config_identity(sm, &identity_len);
150 	if (identity == NULL)
151 		return NULL;
152 
153 	if (data->state != LEAP_WAIT_SUCCESS) {
154 		wpa_printf(MSG_INFO, "EAP-LEAP: EAP-Success received in "
155 			   "unexpected state (%d) - ignored", data->state);
156 		ret->ignore = true;
157 		return NULL;
158 	}
159 
160 	resp = eap_msg_alloc(EAP_VENDOR_IETF, EAP_TYPE_LEAP,
161 			     3 + LEAP_CHALLENGE_LEN + identity_len,
162 			     EAP_CODE_REQUEST, eap_get_id(reqData));
163 	if (resp == NULL)
164 		return NULL;
165 	wpabuf_put_u8(resp, LEAP_VERSION);
166 	wpabuf_put_u8(resp, 0); /* unused */
167 	wpabuf_put_u8(resp, LEAP_CHALLENGE_LEN);
168 	pos = wpabuf_put(resp, LEAP_CHALLENGE_LEN);
169 	if (random_get_bytes(pos, LEAP_CHALLENGE_LEN)) {
170 		wpa_printf(MSG_WARNING, "EAP-LEAP: Failed to read random data "
171 			   "for challenge");
172 		wpabuf_free(resp);
173 		ret->ignore = true;
174 		return NULL;
175 	}
176 	os_memcpy(data->ap_challenge, pos, LEAP_CHALLENGE_LEN);
177 	wpa_hexdump(MSG_MSGDUMP, "EAP-LEAP: Challenge to AP/AS", pos,
178 		    LEAP_CHALLENGE_LEN);
179 	wpabuf_put_data(resp, identity, identity_len);
180 
181 	data->state = LEAP_WAIT_RESPONSE;
182 
183 	return resp;
184 }
185 
186 
eap_leap_process_response(struct eap_sm * sm,void * priv,struct eap_method_ret * ret,const struct wpabuf * reqData)187 static struct wpabuf * eap_leap_process_response(struct eap_sm *sm, void *priv,
188 						 struct eap_method_ret *ret,
189 						 const struct wpabuf *reqData)
190 {
191 	struct eap_leap_data *data = priv;
192 	const u8 *pos, *password;
193 	u8 response_len, pw_hash[16], pw_hash_hash[16],
194 		expected[LEAP_RESPONSE_LEN];
195 	size_t password_len, len;
196 	int pwhash;
197 
198 	wpa_printf(MSG_DEBUG, "EAP-LEAP: Processing EAP-Response");
199 
200 	password = eap_get_config_password2(sm, &password_len, &pwhash);
201 	if (password == NULL)
202 		return NULL;
203 
204 	pos = eap_hdr_validate(EAP_VENDOR_IETF, EAP_TYPE_LEAP, reqData, &len);
205 	if (pos == NULL || len < 3) {
206 		wpa_printf(MSG_INFO, "EAP-LEAP: Invalid EAP-Response frame");
207 		ret->ignore = true;
208 		return NULL;
209 	}
210 
211 	if (*pos != LEAP_VERSION) {
212 		wpa_printf(MSG_WARNING, "EAP-LEAP: Unsupported LEAP version "
213 			   "%d", *pos);
214 		ret->ignore = true;
215 		return NULL;
216 	}
217 	pos++;
218 
219 	pos++; /* skip unused byte */
220 
221 	response_len = *pos++;
222 	if (response_len != LEAP_RESPONSE_LEN || response_len > len - 3) {
223 		wpa_printf(MSG_INFO, "EAP-LEAP: Invalid response "
224 			   "(response_len=%d reqDataLen=%lu)",
225 			   response_len, (unsigned long) wpabuf_len(reqData));
226 		ret->ignore = true;
227 		return NULL;
228 	}
229 
230 	wpa_hexdump(MSG_DEBUG, "EAP-LEAP: Response from AP",
231 		    pos, LEAP_RESPONSE_LEN);
232 	os_memcpy(data->ap_response, pos, LEAP_RESPONSE_LEN);
233 
234 	if (pwhash) {
235 		if (hash_nt_password_hash(password, pw_hash_hash)) {
236 			ret->ignore = true;
237 			return NULL;
238 		}
239 	} else {
240 		if (nt_password_hash(password, password_len, pw_hash) ||
241 		    hash_nt_password_hash(pw_hash, pw_hash_hash)) {
242 			ret->ignore = true;
243 			return NULL;
244 		}
245 	}
246 	if (challenge_response(data->ap_challenge, pw_hash_hash, expected)) {
247 		ret->ignore = true;
248 		return NULL;
249 	}
250 
251 	ret->methodState = METHOD_DONE;
252 	ret->allowNotifications = false;
253 
254 	if (os_memcmp_const(pos, expected, LEAP_RESPONSE_LEN) != 0) {
255 		wpa_printf(MSG_WARNING, "EAP-LEAP: AP sent an invalid "
256 			   "response - authentication failed");
257 		wpa_hexdump(MSG_DEBUG, "EAP-LEAP: Expected response from AP",
258 			    expected, LEAP_RESPONSE_LEN);
259 		ret->decision = DECISION_FAIL;
260 		return NULL;
261 	}
262 
263 	ret->decision = DECISION_UNCOND_SUCC;
264 
265 	/* LEAP is somewhat odd method since it sends EAP-Success in the middle
266 	 * of the authentication. Use special variable to transit EAP state
267 	 * machine to SUCCESS state. */
268 	sm->leap_done = true;
269 	data->state = LEAP_DONE;
270 
271 	/* No more authentication messages expected; AP will send EAPOL-Key
272 	 * frames if encryption is enabled. */
273 	return NULL;
274 }
275 
276 
eap_leap_process(struct eap_sm * sm,void * priv,struct eap_method_ret * ret,const struct wpabuf * reqData)277 static struct wpabuf * eap_leap_process(struct eap_sm *sm, void *priv,
278 					struct eap_method_ret *ret,
279 					const struct wpabuf *reqData)
280 {
281 	const struct eap_hdr *eap;
282 	size_t password_len;
283 	const u8 *password;
284 
285 	password = eap_get_config_password(sm, &password_len);
286 	if (password == NULL) {
287 		wpa_printf(MSG_INFO, "EAP-LEAP: Password not configured");
288 		eap_sm_request_password(sm);
289 		ret->ignore = true;
290 		return NULL;
291 	}
292 
293 	/*
294 	 * LEAP needs to be able to handle EAP-Success frame which does not
295 	 * include Type field. Consequently, eap_hdr_validate() cannot be used
296 	 * here. This validation will be done separately for EAP-Request and
297 	 * EAP-Response frames.
298 	 */
299 	eap = wpabuf_head(reqData);
300 	if (wpabuf_len(reqData) < sizeof(*eap) ||
301 	    be_to_host16(eap->length) > wpabuf_len(reqData)) {
302 		wpa_printf(MSG_INFO, "EAP-LEAP: Invalid frame");
303 		ret->ignore = true;
304 		return NULL;
305 	}
306 
307 	ret->ignore = false;
308 	ret->allowNotifications = true;
309 	ret->methodState = METHOD_MAY_CONT;
310 	ret->decision = DECISION_FAIL;
311 
312 	sm->leap_done = false;
313 
314 	switch (eap->code) {
315 	case EAP_CODE_REQUEST:
316 		return eap_leap_process_request(sm, priv, ret, reqData);
317 	case EAP_CODE_SUCCESS:
318 		return eap_leap_process_success(sm, priv, ret, reqData);
319 	case EAP_CODE_RESPONSE:
320 		return eap_leap_process_response(sm, priv, ret, reqData);
321 	default:
322 		wpa_printf(MSG_INFO, "EAP-LEAP: Unexpected EAP code (%d) - "
323 			   "ignored", eap->code);
324 		ret->ignore = true;
325 		return NULL;
326 	}
327 }
328 
329 
eap_leap_isKeyAvailable(struct eap_sm * sm,void * priv)330 static bool eap_leap_isKeyAvailable(struct eap_sm *sm, void *priv)
331 {
332 	struct eap_leap_data *data = priv;
333 	return data->state == LEAP_DONE;
334 }
335 
336 
eap_leap_getKey(struct eap_sm * sm,void * priv,size_t * len)337 static u8 * eap_leap_getKey(struct eap_sm *sm, void *priv, size_t *len)
338 {
339 	struct eap_leap_data *data = priv;
340 	u8 *key, pw_hash_hash[16], pw_hash[16];
341 	const u8 *addr[5], *password;
342 	size_t elen[5], password_len;
343 	int pwhash;
344 
345 	if (data->state != LEAP_DONE)
346 		return NULL;
347 
348 	password = eap_get_config_password2(sm, &password_len, &pwhash);
349 	if (password == NULL)
350 		return NULL;
351 
352 	key = os_malloc(LEAP_KEY_LEN);
353 	if (key == NULL)
354 		return NULL;
355 
356 	if (pwhash) {
357 		if (hash_nt_password_hash(password, pw_hash_hash)) {
358 			os_free(key);
359 			return NULL;
360 		}
361 	} else {
362 		if (nt_password_hash(password, password_len, pw_hash) ||
363 		    hash_nt_password_hash(pw_hash, pw_hash_hash)) {
364 			os_free(key);
365 			return NULL;
366 		}
367 	}
368 	wpa_hexdump_key(MSG_DEBUG, "EAP-LEAP: pw_hash_hash",
369 			pw_hash_hash, 16);
370 	wpa_hexdump(MSG_DEBUG, "EAP-LEAP: peer_challenge",
371 		    data->peer_challenge, LEAP_CHALLENGE_LEN);
372 	wpa_hexdump(MSG_DEBUG, "EAP-LEAP: peer_response",
373 		    data->peer_response, LEAP_RESPONSE_LEN);
374 	wpa_hexdump(MSG_DEBUG, "EAP-LEAP: ap_challenge",
375 		    data->ap_challenge, LEAP_CHALLENGE_LEN);
376 	wpa_hexdump(MSG_DEBUG, "EAP-LEAP: ap_response",
377 		    data->ap_response, LEAP_RESPONSE_LEN);
378 
379 	addr[0] = pw_hash_hash;
380 	elen[0] = 16;
381 	addr[1] = data->ap_challenge;
382 	elen[1] = LEAP_CHALLENGE_LEN;
383 	addr[2] = data->ap_response;
384 	elen[2] = LEAP_RESPONSE_LEN;
385 	addr[3] = data->peer_challenge;
386 	elen[3] = LEAP_CHALLENGE_LEN;
387 	addr[4] = data->peer_response;
388 	elen[4] = LEAP_RESPONSE_LEN;
389 	md5_vector(5, addr, elen, key);
390 	wpa_hexdump_key(MSG_DEBUG, "EAP-LEAP: master key", key, LEAP_KEY_LEN);
391 	*len = LEAP_KEY_LEN;
392 
393 	forced_memzero(pw_hash, sizeof(pw_hash));
394 	forced_memzero(pw_hash_hash, sizeof(pw_hash_hash));
395 
396 	return key;
397 }
398 
399 
eap_peer_leap_register(void)400 int eap_peer_leap_register(void)
401 {
402 	struct eap_method *eap;
403 
404 	eap = eap_peer_method_alloc(EAP_PEER_METHOD_INTERFACE_VERSION,
405 				    EAP_VENDOR_IETF, EAP_TYPE_LEAP, "LEAP");
406 	if (eap == NULL)
407 		return -1;
408 
409 	eap->init = eap_leap_init;
410 	eap->deinit = eap_leap_deinit;
411 	eap->process = eap_leap_process;
412 	eap->isKeyAvailable = eap_leap_isKeyAvailable;
413 	eap->getKey = eap_leap_getKey;
414 
415 	return eap_peer_method_register(eap);
416 }
417