1/*
2 * hostapd - PMKSA cache for IEEE 802.11i RSN
3 * Copyright (c) 2004-2008, 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 "utils/includes.h"
10
11#include "utils/common.h"
12#include "utils/eloop.h"
13#include "eapol_auth/eapol_auth_sm.h"
14#include "eapol_auth/eapol_auth_sm_i.h"
15#include "sta_info.h"
16#include "ap_config.h"
17#include "pmksa_cache_auth.h"
18
19
20static const int pmksa_cache_max_entries = 1024;
21static const int dot11RSNAConfigPMKLifetime = 43200;
22
23struct rsn_pmksa_cache {
24#define PMKID_HASH_SIZE 128
25#define PMKID_HASH(pmkid) (unsigned int) ((pmkid)[0] & 0x7f)
26	struct rsn_pmksa_cache_entry *pmkid[PMKID_HASH_SIZE];
27	struct rsn_pmksa_cache_entry *pmksa;
28	int pmksa_count;
29
30	void (*free_cb)(struct rsn_pmksa_cache_entry *entry, void *ctx);
31	void *ctx;
32};
33
34
35static void pmksa_cache_set_expiration(struct rsn_pmksa_cache *pmksa);
36
37
38static void _pmksa_cache_free_entry(struct rsn_pmksa_cache_entry *entry)
39{
40	if (entry == NULL)
41		return;
42	os_free(entry->identity);
43#ifndef CONFIG_NO_RADIUS
44	radius_free_class(&entry->radius_class);
45#endif /* CONFIG_NO_RADIUS */
46	os_free(entry);
47}
48
49
50static void pmksa_cache_free_entry(struct rsn_pmksa_cache *pmksa,
51				   struct rsn_pmksa_cache_entry *entry)
52{
53	struct rsn_pmksa_cache_entry *pos, *prev;
54
55	pmksa->pmksa_count--;
56	pmksa->free_cb(entry, pmksa->ctx);
57	pos = pmksa->pmkid[PMKID_HASH(entry->pmkid)];
58	prev = NULL;
59	while (pos) {
60		if (pos == entry) {
61			if (prev != NULL) {
62				prev->hnext = pos->hnext;
63			} else {
64				pmksa->pmkid[PMKID_HASH(entry->pmkid)] =
65					pos->hnext;
66			}
67			break;
68		}
69		prev = pos;
70		pos = pos->hnext;
71	}
72
73	pos = pmksa->pmksa;
74	prev = NULL;
75	while (pos) {
76		if (pos == entry) {
77			if (prev != NULL)
78				prev->next = pos->next;
79			else
80				pmksa->pmksa = pos->next;
81			break;
82		}
83		prev = pos;
84		pos = pos->next;
85	}
86	_pmksa_cache_free_entry(entry);
87}
88
89
90static void pmksa_cache_expire(void *eloop_ctx, void *timeout_ctx)
91{
92	struct rsn_pmksa_cache *pmksa = eloop_ctx;
93	struct os_time now;
94
95	os_get_time(&now);
96	while (pmksa->pmksa && pmksa->pmksa->expiration <= now.sec) {
97		struct rsn_pmksa_cache_entry *entry = pmksa->pmksa;
98		pmksa->pmksa = entry->next;
99		wpa_printf(MSG_DEBUG, "RSN: expired PMKSA cache entry for "
100			   MACSTR, MAC2STR(entry->spa));
101		pmksa_cache_free_entry(pmksa, entry);
102	}
103
104	pmksa_cache_set_expiration(pmksa);
105}
106
107
108static void pmksa_cache_set_expiration(struct rsn_pmksa_cache *pmksa)
109{
110	int sec;
111	struct os_time now;
112
113	eloop_cancel_timeout(pmksa_cache_expire, pmksa, NULL);
114	if (pmksa->pmksa == NULL)
115		return;
116	os_get_time(&now);
117	sec = pmksa->pmksa->expiration - now.sec;
118	if (sec < 0)
119		sec = 0;
120	eloop_register_timeout(sec + 1, 0, pmksa_cache_expire, pmksa, NULL);
121}
122
123
124static void pmksa_cache_from_eapol_data(struct rsn_pmksa_cache_entry *entry,
125					struct eapol_state_machine *eapol)
126{
127	if (eapol == NULL)
128		return;
129
130	if (eapol->identity) {
131		entry->identity = os_malloc(eapol->identity_len);
132		if (entry->identity) {
133			entry->identity_len = eapol->identity_len;
134			os_memcpy(entry->identity, eapol->identity,
135				  eapol->identity_len);
136		}
137	}
138
139#ifndef CONFIG_NO_RADIUS
140	radius_copy_class(&entry->radius_class, &eapol->radius_class);
141#endif /* CONFIG_NO_RADIUS */
142
143	entry->eap_type_authsrv = eapol->eap_type_authsrv;
144	entry->vlan_id = ((struct sta_info *) eapol->sta)->vlan_id;
145}
146
147
148void pmksa_cache_to_eapol_data(struct rsn_pmksa_cache_entry *entry,
149			       struct eapol_state_machine *eapol)
150{
151	if (entry == NULL || eapol == NULL)
152		return;
153
154	if (entry->identity) {
155		os_free(eapol->identity);
156		eapol->identity = os_malloc(entry->identity_len);
157		if (eapol->identity) {
158			eapol->identity_len = entry->identity_len;
159			os_memcpy(eapol->identity, entry->identity,
160				  entry->identity_len);
161		}
162		wpa_hexdump_ascii(MSG_DEBUG, "STA identity from PMKSA",
163				  eapol->identity, eapol->identity_len);
164	}
165
166#ifndef CONFIG_NO_RADIUS
167	radius_free_class(&eapol->radius_class);
168	radius_copy_class(&eapol->radius_class, &entry->radius_class);
169#endif /* CONFIG_NO_RADIUS */
170	if (eapol->radius_class.attr) {
171		wpa_printf(MSG_DEBUG, "Copied %lu Class attribute(s) from "
172			   "PMKSA", (unsigned long) eapol->radius_class.count);
173	}
174
175	eapol->eap_type_authsrv = entry->eap_type_authsrv;
176	((struct sta_info *) eapol->sta)->vlan_id = entry->vlan_id;
177}
178
179
180static void pmksa_cache_link_entry(struct rsn_pmksa_cache *pmksa,
181				   struct rsn_pmksa_cache_entry *entry)
182{
183	struct rsn_pmksa_cache_entry *pos, *prev;
184
185	/* Add the new entry; order by expiration time */
186	pos = pmksa->pmksa;
187	prev = NULL;
188	while (pos) {
189		if (pos->expiration > entry->expiration)
190			break;
191		prev = pos;
192		pos = pos->next;
193	}
194	if (prev == NULL) {
195		entry->next = pmksa->pmksa;
196		pmksa->pmksa = entry;
197	} else {
198		entry->next = prev->next;
199		prev->next = entry;
200	}
201	entry->hnext = pmksa->pmkid[PMKID_HASH(entry->pmkid)];
202	pmksa->pmkid[PMKID_HASH(entry->pmkid)] = entry;
203
204	pmksa->pmksa_count++;
205	wpa_printf(MSG_DEBUG, "RSN: added PMKSA cache entry for " MACSTR,
206		   MAC2STR(entry->spa));
207	wpa_hexdump(MSG_DEBUG, "RSN: added PMKID", entry->pmkid, PMKID_LEN);
208}
209
210
211/**
212 * pmksa_cache_auth_add - Add a PMKSA cache entry
213 * @pmksa: Pointer to PMKSA cache data from pmksa_cache_auth_init()
214 * @pmk: The new pairwise master key
215 * @pmk_len: PMK length in bytes, usually PMK_LEN (32)
216 * @aa: Authenticator address
217 * @spa: Supplicant address
218 * @session_timeout: Session timeout
219 * @eapol: Pointer to EAPOL state machine data
220 * @akmp: WPA_KEY_MGMT_* used in key derivation
221 * Returns: Pointer to the added PMKSA cache entry or %NULL on error
222 *
223 * This function create a PMKSA entry for a new PMK and adds it to the PMKSA
224 * cache. If an old entry is already in the cache for the same Supplicant,
225 * this entry will be replaced with the new entry. PMKID will be calculated
226 * based on the PMK.
227 */
228struct rsn_pmksa_cache_entry *
229pmksa_cache_auth_add(struct rsn_pmksa_cache *pmksa,
230		     const u8 *pmk, size_t pmk_len,
231		const u8 *aa, const u8 *spa, int session_timeout,
232		struct eapol_state_machine *eapol, int akmp)
233{
234	struct rsn_pmksa_cache_entry *entry, *pos;
235	struct os_time now;
236
237	if (pmk_len > PMK_LEN)
238		return NULL;
239
240	entry = os_zalloc(sizeof(*entry));
241	if (entry == NULL)
242		return NULL;
243	os_memcpy(entry->pmk, pmk, pmk_len);
244	entry->pmk_len = pmk_len;
245	rsn_pmkid(pmk, pmk_len, aa, spa, entry->pmkid,
246		  wpa_key_mgmt_sha256(akmp));
247	os_get_time(&now);
248	entry->expiration = now.sec;
249	if (session_timeout > 0)
250		entry->expiration += session_timeout;
251	else
252		entry->expiration += dot11RSNAConfigPMKLifetime;
253	entry->akmp = akmp;
254	os_memcpy(entry->spa, spa, ETH_ALEN);
255	pmksa_cache_from_eapol_data(entry, eapol);
256
257	/* Replace an old entry for the same STA (if found) with the new entry
258	 */
259	pos = pmksa_cache_auth_get(pmksa, spa, NULL);
260	if (pos)
261		pmksa_cache_free_entry(pmksa, pos);
262
263	if (pmksa->pmksa_count >= pmksa_cache_max_entries && pmksa->pmksa) {
264		/* Remove the oldest entry to make room for the new entry */
265		wpa_printf(MSG_DEBUG, "RSN: removed the oldest PMKSA cache "
266			   "entry (for " MACSTR ") to make room for new one",
267			   MAC2STR(pmksa->pmksa->spa));
268		pmksa_cache_free_entry(pmksa, pmksa->pmksa);
269	}
270
271	pmksa_cache_link_entry(pmksa, entry);
272
273	return entry;
274}
275
276
277struct rsn_pmksa_cache_entry *
278pmksa_cache_add_okc(struct rsn_pmksa_cache *pmksa,
279		    const struct rsn_pmksa_cache_entry *old_entry,
280		    const u8 *aa, const u8 *pmkid)
281{
282	struct rsn_pmksa_cache_entry *entry;
283
284	entry = os_zalloc(sizeof(*entry));
285	if (entry == NULL)
286		return NULL;
287	os_memcpy(entry->pmkid, pmkid, PMKID_LEN);
288	os_memcpy(entry->pmk, old_entry->pmk, old_entry->pmk_len);
289	entry->pmk_len = old_entry->pmk_len;
290	entry->expiration = old_entry->expiration;
291	entry->akmp = old_entry->akmp;
292	os_memcpy(entry->spa, old_entry->spa, ETH_ALEN);
293	entry->opportunistic = 1;
294	if (old_entry->identity) {
295		entry->identity = os_malloc(old_entry->identity_len);
296		if (entry->identity) {
297			entry->identity_len = old_entry->identity_len;
298			os_memcpy(entry->identity, old_entry->identity,
299				  old_entry->identity_len);
300		}
301	}
302#ifndef CONFIG_NO_RADIUS
303	radius_copy_class(&entry->radius_class, &old_entry->radius_class);
304#endif /* CONFIG_NO_RADIUS */
305	entry->eap_type_authsrv = old_entry->eap_type_authsrv;
306	entry->vlan_id = old_entry->vlan_id;
307	entry->opportunistic = 1;
308
309	pmksa_cache_link_entry(pmksa, entry);
310
311	return entry;
312}
313
314
315/**
316 * pmksa_cache_auth_deinit - Free all entries in PMKSA cache
317 * @pmksa: Pointer to PMKSA cache data from pmksa_cache_auth_init()
318 */
319void pmksa_cache_auth_deinit(struct rsn_pmksa_cache *pmksa)
320{
321	struct rsn_pmksa_cache_entry *entry, *prev;
322	int i;
323
324	if (pmksa == NULL)
325		return;
326
327	entry = pmksa->pmksa;
328	while (entry) {
329		prev = entry;
330		entry = entry->next;
331		_pmksa_cache_free_entry(prev);
332	}
333	eloop_cancel_timeout(pmksa_cache_expire, pmksa, NULL);
334	for (i = 0; i < PMKID_HASH_SIZE; i++)
335		pmksa->pmkid[i] = NULL;
336	os_free(pmksa);
337}
338
339
340/**
341 * pmksa_cache_auth_get - Fetch a PMKSA cache entry
342 * @pmksa: Pointer to PMKSA cache data from pmksa_cache_auth_init()
343 * @spa: Supplicant address or %NULL to match any
344 * @pmkid: PMKID or %NULL to match any
345 * Returns: Pointer to PMKSA cache entry or %NULL if no match was found
346 */
347struct rsn_pmksa_cache_entry *
348pmksa_cache_auth_get(struct rsn_pmksa_cache *pmksa,
349		     const u8 *spa, const u8 *pmkid)
350{
351	struct rsn_pmksa_cache_entry *entry;
352
353	if (pmkid)
354		entry = pmksa->pmkid[PMKID_HASH(pmkid)];
355	else
356		entry = pmksa->pmksa;
357	while (entry) {
358		if ((spa == NULL ||
359		     os_memcmp(entry->spa, spa, ETH_ALEN) == 0) &&
360		    (pmkid == NULL ||
361		     os_memcmp(entry->pmkid, pmkid, PMKID_LEN) == 0))
362			return entry;
363		entry = pmkid ? entry->hnext : entry->next;
364	}
365	return NULL;
366}
367
368
369/**
370 * pmksa_cache_get_okc - Fetch a PMKSA cache entry using OKC
371 * @pmksa: Pointer to PMKSA cache data from pmksa_cache_auth_init()
372 * @aa: Authenticator address
373 * @spa: Supplicant address
374 * @pmkid: PMKID
375 * Returns: Pointer to PMKSA cache entry or %NULL if no match was found
376 *
377 * Use opportunistic key caching (OKC) to find a PMK for a supplicant.
378 */
379struct rsn_pmksa_cache_entry * pmksa_cache_get_okc(
380	struct rsn_pmksa_cache *pmksa, const u8 *aa, const u8 *spa,
381	const u8 *pmkid)
382{
383	struct rsn_pmksa_cache_entry *entry;
384	u8 new_pmkid[PMKID_LEN];
385
386	entry = pmksa->pmksa;
387	while (entry) {
388		if (os_memcmp(entry->spa, spa, ETH_ALEN) != 0)
389			continue;
390		rsn_pmkid(entry->pmk, entry->pmk_len, aa, spa, new_pmkid,
391			  wpa_key_mgmt_sha256(entry->akmp));
392		if (os_memcmp(new_pmkid, pmkid, PMKID_LEN) == 0)
393			return entry;
394		entry = entry->next;
395	}
396	return NULL;
397}
398
399
400/**
401 * pmksa_cache_auth_init - Initialize PMKSA cache
402 * @free_cb: Callback function to be called when a PMKSA cache entry is freed
403 * @ctx: Context pointer for free_cb function
404 * Returns: Pointer to PMKSA cache data or %NULL on failure
405 */
406struct rsn_pmksa_cache *
407pmksa_cache_auth_init(void (*free_cb)(struct rsn_pmksa_cache_entry *entry,
408				      void *ctx), void *ctx)
409{
410	struct rsn_pmksa_cache *pmksa;
411
412	pmksa = os_zalloc(sizeof(*pmksa));
413	if (pmksa) {
414		pmksa->free_cb = free_cb;
415		pmksa->ctx = ctx;
416	}
417
418	return pmksa;
419}
420