1/*
2 * hostapd / EAP-SIM (RFC 4186)
3 * Copyright (c) 2005-2012, 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/random.h"
13#include "eap_server/eap_i.h"
14#include "eap_common/eap_sim_common.h"
15#include "eap_server/eap_sim_db.h"
16
17
18struct eap_sim_data {
19	u8 mk[EAP_SIM_MK_LEN];
20	u8 nonce_mt[EAP_SIM_NONCE_MT_LEN];
21	u8 nonce_s[EAP_SIM_NONCE_S_LEN];
22	u8 k_aut[EAP_SIM_K_AUT_LEN];
23	u8 k_encr[EAP_SIM_K_ENCR_LEN];
24	u8 msk[EAP_SIM_KEYING_DATA_LEN];
25	u8 emsk[EAP_EMSK_LEN];
26	u8 kc[EAP_SIM_MAX_CHAL][EAP_SIM_KC_LEN];
27	u8 sres[EAP_SIM_MAX_CHAL][EAP_SIM_SRES_LEN];
28	u8 rand[EAP_SIM_MAX_CHAL][GSM_RAND_LEN];
29	int num_chal;
30	enum {
31		START, CHALLENGE, REAUTH, NOTIFICATION, SUCCESS, FAILURE
32	} state;
33	char *next_pseudonym;
34	char *next_reauth_id;
35	u16 counter;
36	struct eap_sim_reauth *reauth;
37	u16 notification;
38	int use_result_ind;
39	int start_round;
40	char permanent[20]; /* Permanent username */
41};
42
43
44static const char * eap_sim_state_txt(int state)
45{
46	switch (state) {
47	case START:
48		return "START";
49	case CHALLENGE:
50		return "CHALLENGE";
51	case REAUTH:
52		return "REAUTH";
53	case SUCCESS:
54		return "SUCCESS";
55	case FAILURE:
56		return "FAILURE";
57	case NOTIFICATION:
58		return "NOTIFICATION";
59	default:
60		return "Unknown?!";
61	}
62}
63
64
65static void eap_sim_state(struct eap_sim_data *data, int state)
66{
67	wpa_printf(MSG_DEBUG, "EAP-SIM: %s -> %s",
68		   eap_sim_state_txt(data->state),
69		   eap_sim_state_txt(state));
70	data->state = state;
71}
72
73
74static void * eap_sim_init(struct eap_sm *sm)
75{
76	struct eap_sim_data *data;
77
78	if (sm->eap_sim_db_priv == NULL) {
79		wpa_printf(MSG_WARNING, "EAP-SIM: eap_sim_db not configured");
80		return NULL;
81	}
82
83	data = os_zalloc(sizeof(*data));
84	if (data == NULL)
85		return NULL;
86	data->state = START;
87
88	return data;
89}
90
91
92static void eap_sim_reset(struct eap_sm *sm, void *priv)
93{
94	struct eap_sim_data *data = priv;
95	os_free(data->next_pseudonym);
96	os_free(data->next_reauth_id);
97	os_free(data);
98}
99
100
101static struct wpabuf * eap_sim_build_start(struct eap_sm *sm,
102					   struct eap_sim_data *data, u8 id)
103{
104	struct eap_sim_msg *msg;
105	u8 ver[2];
106
107	wpa_printf(MSG_DEBUG, "EAP-SIM: Generating Start");
108	msg = eap_sim_msg_init(EAP_CODE_REQUEST, id, EAP_TYPE_SIM,
109			       EAP_SIM_SUBTYPE_START);
110	data->start_round++;
111	if (data->start_round == 1) {
112		/*
113		 * RFC 4186, Chap. 4.2.4 recommends that identity from EAP is
114		 * ignored and the SIM/Start is used to request the identity.
115		 */
116		wpa_printf(MSG_DEBUG, "   AT_ANY_ID_REQ");
117		eap_sim_msg_add(msg, EAP_SIM_AT_ANY_ID_REQ, 0, NULL, 0);
118	} else if (data->start_round > 3) {
119		/* Cannot use more than three rounds of Start messages */
120		eap_sim_msg_free(msg);
121		return NULL;
122	} else if (data->start_round == 0) {
123		/*
124		 * This is a special case that is used to recover from
125		 * AT_COUNTER_TOO_SMALL during re-authentication. Since we
126		 * already know the identity of the peer, there is no need to
127		 * request any identity in this case.
128		 */
129	} else if (sm->identity && sm->identity_len > 0 &&
130		   sm->identity[0] == EAP_SIM_REAUTH_ID_PREFIX) {
131		/* Reauth id may have expired - try fullauth */
132		wpa_printf(MSG_DEBUG, "   AT_FULLAUTH_ID_REQ");
133		eap_sim_msg_add(msg, EAP_SIM_AT_FULLAUTH_ID_REQ, 0, NULL, 0);
134	} else {
135		wpa_printf(MSG_DEBUG, "   AT_PERMANENT_ID_REQ");
136		eap_sim_msg_add(msg, EAP_SIM_AT_PERMANENT_ID_REQ, 0, NULL, 0);
137	}
138	wpa_printf(MSG_DEBUG, "   AT_VERSION_LIST");
139	ver[0] = 0;
140	ver[1] = EAP_SIM_VERSION;
141	eap_sim_msg_add(msg, EAP_SIM_AT_VERSION_LIST, sizeof(ver),
142			ver, sizeof(ver));
143	return eap_sim_msg_finish(msg, NULL, NULL, 0);
144}
145
146
147static int eap_sim_build_encr(struct eap_sm *sm, struct eap_sim_data *data,
148			      struct eap_sim_msg *msg, u16 counter,
149			      const u8 *nonce_s)
150{
151	os_free(data->next_pseudonym);
152	if (nonce_s == NULL) {
153		data->next_pseudonym =
154			eap_sim_db_get_next_pseudonym(sm->eap_sim_db_priv,
155						      EAP_SIM_DB_SIM);
156	} else {
157		/* Do not update pseudonym during re-authentication */
158		data->next_pseudonym = NULL;
159	}
160	os_free(data->next_reauth_id);
161	if (data->counter <= EAP_SIM_MAX_FAST_REAUTHS) {
162		data->next_reauth_id =
163			eap_sim_db_get_next_reauth_id(sm->eap_sim_db_priv,
164						      EAP_SIM_DB_SIM);
165	} else {
166		wpa_printf(MSG_DEBUG, "EAP-SIM: Max fast re-authentication "
167			   "count exceeded - force full authentication");
168		data->next_reauth_id = NULL;
169	}
170
171	if (data->next_pseudonym == NULL && data->next_reauth_id == NULL &&
172	    counter == 0 && nonce_s == NULL)
173		return 0;
174
175	wpa_printf(MSG_DEBUG, "   AT_IV");
176	wpa_printf(MSG_DEBUG, "   AT_ENCR_DATA");
177	eap_sim_msg_add_encr_start(msg, EAP_SIM_AT_IV, EAP_SIM_AT_ENCR_DATA);
178
179	if (counter > 0) {
180		wpa_printf(MSG_DEBUG, "   *AT_COUNTER (%u)", counter);
181		eap_sim_msg_add(msg, EAP_SIM_AT_COUNTER, counter, NULL, 0);
182	}
183
184	if (nonce_s) {
185		wpa_printf(MSG_DEBUG, "   *AT_NONCE_S");
186		eap_sim_msg_add(msg, EAP_SIM_AT_NONCE_S, 0, nonce_s,
187				EAP_SIM_NONCE_S_LEN);
188	}
189
190	if (data->next_pseudonym) {
191		wpa_printf(MSG_DEBUG, "   *AT_NEXT_PSEUDONYM (%s)",
192			   data->next_pseudonym);
193		eap_sim_msg_add(msg, EAP_SIM_AT_NEXT_PSEUDONYM,
194				os_strlen(data->next_pseudonym),
195				(u8 *) data->next_pseudonym,
196				os_strlen(data->next_pseudonym));
197	}
198
199	if (data->next_reauth_id) {
200		wpa_printf(MSG_DEBUG, "   *AT_NEXT_REAUTH_ID (%s)",
201			   data->next_reauth_id);
202		eap_sim_msg_add(msg, EAP_SIM_AT_NEXT_REAUTH_ID,
203				os_strlen(data->next_reauth_id),
204				(u8 *) data->next_reauth_id,
205				os_strlen(data->next_reauth_id));
206	}
207
208	if (eap_sim_msg_add_encr_end(msg, data->k_encr, EAP_SIM_AT_PADDING)) {
209		wpa_printf(MSG_WARNING, "EAP-SIM: Failed to encrypt "
210			   "AT_ENCR_DATA");
211		return -1;
212	}
213
214	return 0;
215}
216
217
218static struct wpabuf * eap_sim_build_challenge(struct eap_sm *sm,
219					       struct eap_sim_data *data,
220					       u8 id)
221{
222	struct eap_sim_msg *msg;
223
224	wpa_printf(MSG_DEBUG, "EAP-SIM: Generating Challenge");
225	msg = eap_sim_msg_init(EAP_CODE_REQUEST, id, EAP_TYPE_SIM,
226			       EAP_SIM_SUBTYPE_CHALLENGE);
227	wpa_printf(MSG_DEBUG, "   AT_RAND");
228	eap_sim_msg_add(msg, EAP_SIM_AT_RAND, 0, (u8 *) data->rand,
229			data->num_chal * GSM_RAND_LEN);
230
231	if (eap_sim_build_encr(sm, data, msg, 0, NULL)) {
232		eap_sim_msg_free(msg);
233		return NULL;
234	}
235
236	if (sm->eap_sim_aka_result_ind) {
237		wpa_printf(MSG_DEBUG, "   AT_RESULT_IND");
238		eap_sim_msg_add(msg, EAP_SIM_AT_RESULT_IND, 0, NULL, 0);
239	}
240
241	wpa_printf(MSG_DEBUG, "   AT_MAC");
242	eap_sim_msg_add_mac(msg, EAP_SIM_AT_MAC);
243	return eap_sim_msg_finish(msg, data->k_aut, data->nonce_mt,
244				  EAP_SIM_NONCE_MT_LEN);
245}
246
247
248static struct wpabuf * eap_sim_build_reauth(struct eap_sm *sm,
249					    struct eap_sim_data *data, u8 id)
250{
251	struct eap_sim_msg *msg;
252
253	wpa_printf(MSG_DEBUG, "EAP-SIM: Generating Re-authentication");
254
255	if (random_get_bytes(data->nonce_s, EAP_SIM_NONCE_S_LEN))
256		return NULL;
257	wpa_hexdump_key(MSG_MSGDUMP, "EAP-SIM: NONCE_S",
258			data->nonce_s, EAP_SIM_NONCE_S_LEN);
259
260	eap_sim_derive_keys(data->mk, data->k_encr, data->k_aut, data->msk,
261			    data->emsk);
262	eap_sim_derive_keys_reauth(data->counter, sm->identity,
263				   sm->identity_len, data->nonce_s, data->mk,
264				   data->msk, data->emsk);
265
266	msg = eap_sim_msg_init(EAP_CODE_REQUEST, id, EAP_TYPE_SIM,
267			       EAP_SIM_SUBTYPE_REAUTHENTICATION);
268
269	if (eap_sim_build_encr(sm, data, msg, data->counter, data->nonce_s)) {
270		eap_sim_msg_free(msg);
271		return NULL;
272	}
273
274	if (sm->eap_sim_aka_result_ind) {
275		wpa_printf(MSG_DEBUG, "   AT_RESULT_IND");
276		eap_sim_msg_add(msg, EAP_SIM_AT_RESULT_IND, 0, NULL, 0);
277	}
278
279	wpa_printf(MSG_DEBUG, "   AT_MAC");
280	eap_sim_msg_add_mac(msg, EAP_SIM_AT_MAC);
281	return eap_sim_msg_finish(msg, data->k_aut, NULL, 0);
282}
283
284
285static struct wpabuf * eap_sim_build_notification(struct eap_sm *sm,
286						  struct eap_sim_data *data,
287						  u8 id)
288{
289	struct eap_sim_msg *msg;
290
291	wpa_printf(MSG_DEBUG, "EAP-SIM: Generating Notification");
292	msg = eap_sim_msg_init(EAP_CODE_REQUEST, id, EAP_TYPE_SIM,
293			       EAP_SIM_SUBTYPE_NOTIFICATION);
294	wpa_printf(MSG_DEBUG, "   AT_NOTIFICATION (%d)", data->notification);
295	eap_sim_msg_add(msg, EAP_SIM_AT_NOTIFICATION, data->notification,
296			NULL, 0);
297	if (data->use_result_ind) {
298		if (data->reauth) {
299			wpa_printf(MSG_DEBUG, "   AT_IV");
300			wpa_printf(MSG_DEBUG, "   AT_ENCR_DATA");
301			eap_sim_msg_add_encr_start(msg, EAP_SIM_AT_IV,
302						   EAP_SIM_AT_ENCR_DATA);
303			wpa_printf(MSG_DEBUG, "   *AT_COUNTER (%u)",
304				   data->counter);
305			eap_sim_msg_add(msg, EAP_SIM_AT_COUNTER, data->counter,
306					NULL, 0);
307
308			if (eap_sim_msg_add_encr_end(msg, data->k_encr,
309						     EAP_SIM_AT_PADDING)) {
310				wpa_printf(MSG_WARNING, "EAP-SIM: Failed to "
311					   "encrypt AT_ENCR_DATA");
312				eap_sim_msg_free(msg);
313				return NULL;
314			}
315		}
316
317		wpa_printf(MSG_DEBUG, "   AT_MAC");
318		eap_sim_msg_add_mac(msg, EAP_SIM_AT_MAC);
319	}
320	return eap_sim_msg_finish(msg, data->k_aut, NULL, 0);
321}
322
323
324static struct wpabuf * eap_sim_buildReq(struct eap_sm *sm, void *priv, u8 id)
325{
326	struct eap_sim_data *data = priv;
327
328	switch (data->state) {
329	case START:
330		return eap_sim_build_start(sm, data, id);
331	case CHALLENGE:
332		return eap_sim_build_challenge(sm, data, id);
333	case REAUTH:
334		return eap_sim_build_reauth(sm, data, id);
335	case NOTIFICATION:
336		return eap_sim_build_notification(sm, data, id);
337	default:
338		wpa_printf(MSG_DEBUG, "EAP-SIM: Unknown state %d in "
339			   "buildReq", data->state);
340		break;
341	}
342	return NULL;
343}
344
345
346static Boolean eap_sim_check(struct eap_sm *sm, void *priv,
347			     struct wpabuf *respData)
348{
349	const u8 *pos;
350	size_t len;
351
352	pos = eap_hdr_validate(EAP_VENDOR_IETF, EAP_TYPE_SIM, respData, &len);
353	if (pos == NULL || len < 3) {
354		wpa_printf(MSG_INFO, "EAP-SIM: Invalid frame");
355		return TRUE;
356	}
357
358	return FALSE;
359}
360
361
362static Boolean eap_sim_unexpected_subtype(struct eap_sim_data *data,
363					  u8 subtype)
364{
365	if (subtype == EAP_SIM_SUBTYPE_CLIENT_ERROR)
366		return FALSE;
367
368	switch (data->state) {
369	case START:
370		if (subtype != EAP_SIM_SUBTYPE_START) {
371			wpa_printf(MSG_INFO, "EAP-SIM: Unexpected response "
372				   "subtype %d", subtype);
373			return TRUE;
374		}
375		break;
376	case CHALLENGE:
377		if (subtype != EAP_SIM_SUBTYPE_CHALLENGE) {
378			wpa_printf(MSG_INFO, "EAP-SIM: Unexpected response "
379				   "subtype %d", subtype);
380			return TRUE;
381		}
382		break;
383	case REAUTH:
384		if (subtype != EAP_SIM_SUBTYPE_REAUTHENTICATION) {
385			wpa_printf(MSG_INFO, "EAP-SIM: Unexpected response "
386				   "subtype %d", subtype);
387			return TRUE;
388		}
389		break;
390	case NOTIFICATION:
391		if (subtype != EAP_SIM_SUBTYPE_NOTIFICATION) {
392			wpa_printf(MSG_INFO, "EAP-SIM: Unexpected response "
393				   "subtype %d", subtype);
394			return TRUE;
395		}
396		break;
397	default:
398		wpa_printf(MSG_INFO, "EAP-SIM: Unexpected state (%d) for "
399			   "processing a response", data->state);
400		return TRUE;
401	}
402
403	return FALSE;
404}
405
406
407static int eap_sim_supported_ver(struct eap_sim_data *data, int version)
408{
409	return version == EAP_SIM_VERSION;
410}
411
412
413static void eap_sim_process_start(struct eap_sm *sm,
414				  struct eap_sim_data *data,
415				  struct wpabuf *respData,
416				  struct eap_sim_attrs *attr)
417{
418	size_t identity_len;
419	u8 ver_list[2];
420	u8 *new_identity;
421	char *username;
422
423	wpa_printf(MSG_DEBUG, "EAP-SIM: Receive start response");
424
425	if (data->start_round == 0) {
426		/*
427		 * Special case for AT_COUNTER_TOO_SMALL recovery - no identity
428		 * was requested since we already know it.
429		 */
430		goto skip_id_update;
431	}
432
433	/*
434	 * We always request identity in SIM/Start, so the peer is required to
435	 * have replied with one.
436	 */
437	if (!attr->identity || attr->identity_len == 0) {
438		wpa_printf(MSG_DEBUG, "EAP-SIM: Peer did not provide any "
439			   "identity");
440		goto failed;
441	}
442
443	new_identity = os_malloc(attr->identity_len);
444	if (new_identity == NULL)
445		goto failed;
446	os_free(sm->identity);
447	sm->identity = new_identity;
448	os_memcpy(sm->identity, attr->identity, attr->identity_len);
449	sm->identity_len = attr->identity_len;
450
451	wpa_hexdump_ascii(MSG_DEBUG, "EAP-SIM: Identity",
452			  sm->identity, sm->identity_len);
453	username = sim_get_username(sm->identity, sm->identity_len);
454	if (username == NULL)
455		goto failed;
456
457	if (username[0] == EAP_SIM_REAUTH_ID_PREFIX) {
458		wpa_printf(MSG_DEBUG, "EAP-SIM: Reauth username '%s'",
459			   username);
460		data->reauth = eap_sim_db_get_reauth_entry(
461			sm->eap_sim_db_priv, username);
462		os_free(username);
463		if (data->reauth == NULL) {
464			wpa_printf(MSG_DEBUG, "EAP-SIM: Unknown reauth "
465				   "identity - request full auth identity");
466			/* Remain in START state for another round */
467			return;
468		}
469		wpa_printf(MSG_DEBUG, "EAP-SIM: Using fast re-authentication");
470		os_strlcpy(data->permanent, data->reauth->permanent,
471			   sizeof(data->permanent));
472		data->counter = data->reauth->counter;
473		os_memcpy(data->mk, data->reauth->mk, EAP_SIM_MK_LEN);
474		eap_sim_state(data, REAUTH);
475		return;
476	}
477
478	if (username[0] == EAP_SIM_PSEUDONYM_PREFIX) {
479		const char *permanent;
480		wpa_printf(MSG_DEBUG, "EAP-SIM: Pseudonym username '%s'",
481			   username);
482		permanent = eap_sim_db_get_permanent(
483			sm->eap_sim_db_priv, username);
484		os_free(username);
485		if (permanent == NULL) {
486			wpa_printf(MSG_DEBUG, "EAP-SIM: Unknown pseudonym "
487				   "identity - request permanent identity");
488			/* Remain in START state for another round */
489			return;
490		}
491		os_strlcpy(data->permanent, permanent,
492			   sizeof(data->permanent));
493	} else if (username[0] == EAP_SIM_PERMANENT_PREFIX) {
494		wpa_printf(MSG_DEBUG, "EAP-SIM: Permanent username '%s'",
495			   username);
496		os_strlcpy(data->permanent, username, sizeof(data->permanent));
497		os_free(username);
498	} else {
499		wpa_printf(MSG_DEBUG, "EAP-SIM: Unrecognized username '%s'",
500			   username);
501		os_free(username);
502		goto failed;
503	}
504
505skip_id_update:
506	/* Full authentication */
507
508	if (attr->nonce_mt == NULL || attr->selected_version < 0) {
509		wpa_printf(MSG_DEBUG, "EAP-SIM: Start/Response missing "
510			   "required attributes");
511		goto failed;
512	}
513
514	if (!eap_sim_supported_ver(data, attr->selected_version)) {
515		wpa_printf(MSG_DEBUG, "EAP-SIM: Peer selected unsupported "
516			   "version %d", attr->selected_version);
517		goto failed;
518	}
519
520	data->counter = 0; /* reset re-auth counter since this is full auth */
521	data->reauth = NULL;
522
523	data->num_chal = eap_sim_db_get_gsm_triplets(
524		sm->eap_sim_db_priv, data->permanent, EAP_SIM_MAX_CHAL,
525		(u8 *) data->rand, (u8 *) data->kc, (u8 *) data->sres, sm);
526	if (data->num_chal == EAP_SIM_DB_PENDING) {
527		wpa_printf(MSG_DEBUG, "EAP-SIM: GSM authentication triplets "
528			   "not yet available - pending request");
529		sm->method_pending = METHOD_PENDING_WAIT;
530		return;
531	}
532	if (data->num_chal < 2) {
533		wpa_printf(MSG_INFO, "EAP-SIM: Failed to get GSM "
534			   "authentication triplets for the peer");
535		goto failed;
536	}
537
538	identity_len = sm->identity_len;
539	while (identity_len > 0 && sm->identity[identity_len - 1] == '\0') {
540		wpa_printf(MSG_DEBUG, "EAP-SIM: Workaround - drop last null "
541			   "character from identity");
542		identity_len--;
543	}
544	wpa_hexdump_ascii(MSG_DEBUG, "EAP-SIM: Identity for MK derivation",
545			  sm->identity, identity_len);
546
547	os_memcpy(data->nonce_mt, attr->nonce_mt, EAP_SIM_NONCE_MT_LEN);
548	WPA_PUT_BE16(ver_list, EAP_SIM_VERSION);
549	eap_sim_derive_mk(sm->identity, identity_len, attr->nonce_mt,
550			  attr->selected_version, ver_list, sizeof(ver_list),
551			  data->num_chal, (const u8 *) data->kc, data->mk);
552	eap_sim_derive_keys(data->mk, data->k_encr, data->k_aut, data->msk,
553			    data->emsk);
554
555	eap_sim_state(data, CHALLENGE);
556	return;
557
558failed:
559	data->notification = EAP_SIM_GENERAL_FAILURE_BEFORE_AUTH;
560	eap_sim_state(data, NOTIFICATION);
561}
562
563
564static void eap_sim_process_challenge(struct eap_sm *sm,
565				      struct eap_sim_data *data,
566				      struct wpabuf *respData,
567				      struct eap_sim_attrs *attr)
568{
569	if (attr->mac == NULL ||
570	    eap_sim_verify_mac(data->k_aut, respData, attr->mac,
571			       (u8 *) data->sres,
572			       data->num_chal * EAP_SIM_SRES_LEN)) {
573		wpa_printf(MSG_WARNING, "EAP-SIM: Challenge message "
574			   "did not include valid AT_MAC");
575		data->notification = EAP_SIM_GENERAL_FAILURE_BEFORE_AUTH;
576		eap_sim_state(data, NOTIFICATION);
577		return;
578	}
579
580	wpa_printf(MSG_DEBUG, "EAP-SIM: Challenge response includes the "
581		   "correct AT_MAC");
582	if (sm->eap_sim_aka_result_ind && attr->result_ind) {
583		data->use_result_ind = 1;
584		data->notification = EAP_SIM_SUCCESS;
585		eap_sim_state(data, NOTIFICATION);
586	} else
587		eap_sim_state(data, SUCCESS);
588
589	if (data->next_pseudonym) {
590		eap_sim_db_add_pseudonym(sm->eap_sim_db_priv, data->permanent,
591					 data->next_pseudonym);
592		data->next_pseudonym = NULL;
593	}
594	if (data->next_reauth_id) {
595		eap_sim_db_add_reauth(sm->eap_sim_db_priv, data->permanent,
596				      data->next_reauth_id, data->counter + 1,
597				      data->mk);
598		data->next_reauth_id = NULL;
599	}
600}
601
602
603static void eap_sim_process_reauth(struct eap_sm *sm,
604				   struct eap_sim_data *data,
605				   struct wpabuf *respData,
606				   struct eap_sim_attrs *attr)
607{
608	struct eap_sim_attrs eattr;
609	u8 *decrypted = NULL;
610
611	if (attr->mac == NULL ||
612	    eap_sim_verify_mac(data->k_aut, respData, attr->mac, data->nonce_s,
613			       EAP_SIM_NONCE_S_LEN)) {
614		wpa_printf(MSG_WARNING, "EAP-SIM: Re-authentication message "
615			   "did not include valid AT_MAC");
616		goto fail;
617	}
618
619	if (attr->encr_data == NULL || attr->iv == NULL) {
620		wpa_printf(MSG_WARNING, "EAP-SIM: Reauthentication "
621			   "message did not include encrypted data");
622		goto fail;
623	}
624
625	decrypted = eap_sim_parse_encr(data->k_encr, attr->encr_data,
626				       attr->encr_data_len, attr->iv, &eattr,
627				       0);
628	if (decrypted == NULL) {
629		wpa_printf(MSG_WARNING, "EAP-SIM: Failed to parse encrypted "
630			   "data from reauthentication message");
631		goto fail;
632	}
633
634	if (eattr.counter != data->counter) {
635		wpa_printf(MSG_WARNING, "EAP-SIM: Re-authentication message "
636			   "used incorrect counter %u, expected %u",
637			   eattr.counter, data->counter);
638		goto fail;
639	}
640	os_free(decrypted);
641	decrypted = NULL;
642
643	wpa_printf(MSG_DEBUG, "EAP-SIM: Re-authentication response includes "
644		   "the correct AT_MAC");
645
646	if (eattr.counter_too_small) {
647		wpa_printf(MSG_DEBUG, "EAP-AKA: Re-authentication response "
648			   "included AT_COUNTER_TOO_SMALL - starting full "
649			   "authentication");
650		data->start_round = -1;
651		eap_sim_state(data, START);
652		return;
653	}
654
655	if (sm->eap_sim_aka_result_ind && attr->result_ind) {
656		data->use_result_ind = 1;
657		data->notification = EAP_SIM_SUCCESS;
658		eap_sim_state(data, NOTIFICATION);
659	} else
660		eap_sim_state(data, SUCCESS);
661
662	if (data->next_reauth_id) {
663		eap_sim_db_add_reauth(sm->eap_sim_db_priv, data->permanent,
664				      data->next_reauth_id,
665				      data->counter + 1, data->mk);
666		data->next_reauth_id = NULL;
667	} else {
668		eap_sim_db_remove_reauth(sm->eap_sim_db_priv, data->reauth);
669		data->reauth = NULL;
670	}
671
672	return;
673
674fail:
675	data->notification = EAP_SIM_GENERAL_FAILURE_BEFORE_AUTH;
676	eap_sim_state(data, NOTIFICATION);
677	eap_sim_db_remove_reauth(sm->eap_sim_db_priv, data->reauth);
678	data->reauth = NULL;
679	os_free(decrypted);
680}
681
682
683static void eap_sim_process_client_error(struct eap_sm *sm,
684					 struct eap_sim_data *data,
685					 struct wpabuf *respData,
686					 struct eap_sim_attrs *attr)
687{
688	wpa_printf(MSG_DEBUG, "EAP-SIM: Client reported error %d",
689		   attr->client_error_code);
690	if (data->notification == EAP_SIM_SUCCESS && data->use_result_ind)
691		eap_sim_state(data, SUCCESS);
692	else
693		eap_sim_state(data, FAILURE);
694}
695
696
697static void eap_sim_process_notification(struct eap_sm *sm,
698					 struct eap_sim_data *data,
699					 struct wpabuf *respData,
700					 struct eap_sim_attrs *attr)
701{
702	wpa_printf(MSG_DEBUG, "EAP-SIM: Client replied to notification");
703	if (data->notification == EAP_SIM_SUCCESS && data->use_result_ind)
704		eap_sim_state(data, SUCCESS);
705	else
706		eap_sim_state(data, FAILURE);
707}
708
709
710static void eap_sim_process(struct eap_sm *sm, void *priv,
711			    struct wpabuf *respData)
712{
713	struct eap_sim_data *data = priv;
714	const u8 *pos, *end;
715	u8 subtype;
716	size_t len;
717	struct eap_sim_attrs attr;
718
719	pos = eap_hdr_validate(EAP_VENDOR_IETF, EAP_TYPE_SIM, respData, &len);
720	if (pos == NULL || len < 3)
721		return;
722
723	end = pos + len;
724	subtype = *pos;
725	pos += 3;
726
727	if (eap_sim_unexpected_subtype(data, subtype)) {
728		wpa_printf(MSG_DEBUG, "EAP-SIM: Unrecognized or unexpected "
729			   "EAP-SIM Subtype in EAP Response");
730		data->notification = EAP_SIM_GENERAL_FAILURE_BEFORE_AUTH;
731		eap_sim_state(data, NOTIFICATION);
732		return;
733	}
734
735	if (eap_sim_parse_attr(pos, end, &attr, 0, 0)) {
736		wpa_printf(MSG_DEBUG, "EAP-SIM: Failed to parse attributes");
737		if (subtype != EAP_SIM_SUBTYPE_CLIENT_ERROR &&
738		    (data->state == START || data->state == CHALLENGE ||
739		     data->state == REAUTH)) {
740			data->notification =
741				EAP_SIM_GENERAL_FAILURE_BEFORE_AUTH;
742			eap_sim_state(data, NOTIFICATION);
743			return;
744		}
745		eap_sim_state(data, FAILURE);
746		return;
747	}
748
749	if (subtype == EAP_SIM_SUBTYPE_CLIENT_ERROR) {
750		eap_sim_process_client_error(sm, data, respData, &attr);
751		return;
752	}
753
754	switch (data->state) {
755	case START:
756		eap_sim_process_start(sm, data, respData, &attr);
757		break;
758	case CHALLENGE:
759		eap_sim_process_challenge(sm, data, respData, &attr);
760		break;
761	case REAUTH:
762		eap_sim_process_reauth(sm, data, respData, &attr);
763		break;
764	case NOTIFICATION:
765		eap_sim_process_notification(sm, data, respData, &attr);
766		break;
767	default:
768		wpa_printf(MSG_DEBUG, "EAP-SIM: Unknown state %d in "
769			   "process", data->state);
770		break;
771	}
772}
773
774
775static Boolean eap_sim_isDone(struct eap_sm *sm, void *priv)
776{
777	struct eap_sim_data *data = priv;
778	return data->state == SUCCESS || data->state == FAILURE;
779}
780
781
782static u8 * eap_sim_getKey(struct eap_sm *sm, void *priv, size_t *len)
783{
784	struct eap_sim_data *data = priv;
785	u8 *key;
786
787	if (data->state != SUCCESS)
788		return NULL;
789
790	key = os_malloc(EAP_SIM_KEYING_DATA_LEN);
791	if (key == NULL)
792		return NULL;
793	os_memcpy(key, data->msk, EAP_SIM_KEYING_DATA_LEN);
794	*len = EAP_SIM_KEYING_DATA_LEN;
795	return key;
796}
797
798
799static u8 * eap_sim_get_emsk(struct eap_sm *sm, void *priv, size_t *len)
800{
801	struct eap_sim_data *data = priv;
802	u8 *key;
803
804	if (data->state != SUCCESS)
805		return NULL;
806
807	key = os_malloc(EAP_EMSK_LEN);
808	if (key == NULL)
809		return NULL;
810	os_memcpy(key, data->emsk, EAP_EMSK_LEN);
811	*len = EAP_EMSK_LEN;
812	return key;
813}
814
815
816static Boolean eap_sim_isSuccess(struct eap_sm *sm, void *priv)
817{
818	struct eap_sim_data *data = priv;
819	return data->state == SUCCESS;
820}
821
822
823int eap_server_sim_register(void)
824{
825	struct eap_method *eap;
826	int ret;
827
828	eap = eap_server_method_alloc(EAP_SERVER_METHOD_INTERFACE_VERSION,
829				      EAP_VENDOR_IETF, EAP_TYPE_SIM, "SIM");
830	if (eap == NULL)
831		return -1;
832
833	eap->init = eap_sim_init;
834	eap->reset = eap_sim_reset;
835	eap->buildReq = eap_sim_buildReq;
836	eap->check = eap_sim_check;
837	eap->process = eap_sim_process;
838	eap->isDone = eap_sim_isDone;
839	eap->getKey = eap_sim_getKey;
840	eap->isSuccess = eap_sim_isSuccess;
841	eap->get_emsk = eap_sim_get_emsk;
842
843	ret = eap_server_method_register(eap);
844	if (ret)
845		eap_server_method_free(eap);
846	return ret;
847}
848