summaryrefslogtreecommitdiff
path: root/net/mac80211/key.c
blob: 60aaaf471544d8a0b6e745fe1e5ee32eeadf710b (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
/*
 * Copyright 2002-2005, Instant802 Networks, Inc.
 * Copyright 2005-2006, Devicescape Software, Inc.
 * Copyright 2006-2007	Jiri Benc <jbenc@suse.cz>
 * Copyright 2007	Johannes Berg <johannes@sipsolutions.net>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 */

#include <linux/if_ether.h>
#include <linux/etherdevice.h>
#include <linux/list.h>
#include <linux/rcupdate.h>
#include <linux/rtnetlink.h>
#include <net/mac80211.h>
#include "ieee80211_i.h"
#include "debugfs_key.h"
#include "aes_ccm.h"


/*
 * Key handling basics
 *
 * Key handling in mac80211 is done based on per-interface (sub_if_data)
 * keys and per-station keys. Since each station belongs to an interface,
 * each station key also belongs to that interface.
 *
 * Hardware acceleration is done on a best-effort basis, for each key
 * that is eligible the hardware is asked to enable that key but if
 * it cannot do that they key is simply kept for software encryption.
 * There is currently no way of knowing this except by looking into
 * debugfs.
 *
 * All operations here are called under RTNL so no extra locking is
 * required.
 *
 * NOTE: This code requires that sta info *destruction* is done under
 *	 RTNL, otherwise it can try to access already freed STA structs
 *	 when a STA key is being freed.
 */

static const u8 bcast_addr[ETH_ALEN] = { 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF };
static const u8 zero_addr[ETH_ALEN];

static const u8 *get_mac_for_key(struct ieee80211_key *key)
{
	const u8 *addr = bcast_addr;

	/*
	 * If we're an AP we won't ever receive frames with a non-WEP
	 * group key so we tell the driver that by using the zero MAC
	 * address to indicate a transmit-only key.
	 */
	if (key->conf.alg != ALG_WEP &&
	    (key->sdata->vif.type == IEEE80211_IF_TYPE_AP ||
	     key->sdata->vif.type == IEEE80211_IF_TYPE_VLAN))
		addr = zero_addr;

	if (key->sta)
		addr = key->sta->addr;

	return addr;
}

static void ieee80211_key_enable_hw_accel(struct ieee80211_key *key)
{
	const u8 *addr;
	int ret;
	DECLARE_MAC_BUF(mac);

	if (!key->local->ops->set_key)
		return;

	addr = get_mac_for_key(key);

	ret = key->local->ops->set_key(local_to_hw(key->local), SET_KEY,
				       key->sdata->dev->dev_addr, addr,
				       &key->conf);

	if (!ret)
		key->flags |= KEY_FLAG_UPLOADED_TO_HARDWARE;

	if (ret && ret != -ENOSPC && ret != -EOPNOTSUPP)
		printk(KERN_ERR "mac80211-%s: failed to set key "
		       "(%d, %s) to hardware (%d)\n",
		       wiphy_name(key->local->hw.wiphy),
		       key->conf.keyidx, print_mac(mac, addr), ret);
}

static void ieee80211_key_mark_hw_accel_off(struct ieee80211_key *key)
{
	if (key->flags & KEY_FLAG_UPLOADED_TO_HARDWARE) {
		key->flags &= ~KEY_FLAG_UPLOADED_TO_HARDWARE;
		key->flags |= KEY_FLAG_REMOVE_FROM_HARDWARE;
	}
}

static void ieee80211_key_disable_hw_accel(struct ieee80211_key *key)
{
	const u8 *addr;
	int ret;
	DECLARE_MAC_BUF(mac);

	if (!key || !key->local->ops->set_key)
		return;

	if (!(key->flags & KEY_FLAG_UPLOADED_TO_HARDWARE) &&
	    !(key->flags & KEY_FLAG_REMOVE_FROM_HARDWARE))
		return;

	addr = get_mac_for_key(key);

	ret = key->local->ops->set_key(local_to_hw(key->local), DISABLE_KEY,
				       key->sdata->dev->dev_addr, addr,
				       &key->conf);

	if (ret)
		printk(KERN_ERR "mac80211-%s: failed to remove key "
		       "(%d, %s) from hardware (%d)\n",
		       wiphy_name(key->local->hw.wiphy),
		       key->conf.keyidx, print_mac(mac, addr), ret);

	key->flags &= ~(KEY_FLAG_UPLOADED_TO_HARDWARE |
			KEY_FLAG_REMOVE_FROM_HARDWARE);
}

struct ieee80211_key *ieee80211_key_alloc(enum ieee80211_key_alg alg,
					  int idx,
					  size_t key_len,
					  const u8 *key_data)
{
	struct ieee80211_key *key;

	BUG_ON(idx < 0 || idx >= NUM_DEFAULT_KEYS);

	key = kzalloc(sizeof(struct ieee80211_key) + key_len, GFP_KERNEL);
	if (!key)
		return NULL;

	/*
	 * Default to software encryption; we'll later upload the
	 * key to the hardware if possible.
	 */
	key->conf.flags = 0;
	key->flags = 0;

	key->conf.alg = alg;
	key->conf.keyidx = idx;
	key->conf.keylen = key_len;
	memcpy(key->conf.key, key_data, key_len);

	if (alg == ALG_CCMP) {
		/*
		 * Initialize AES key state here as an optimization so that
		 * it does not need to be initialized for every packet.
		 */
		key->u.ccmp.tfm = ieee80211_aes_key_setup_encrypt(key_data);
		if (!key->u.ccmp.tfm) {
			ieee80211_key_free(key);
			return NULL;
		}
	}

	return key;
}

static void __ieee80211_key_replace(struct ieee80211_sub_if_data *sdata,
				    struct sta_info *sta,
				    struct ieee80211_key *key,
				    struct ieee80211_key *new)
{
	int idx, defkey;

	if (sta) {
		rcu_assign_pointer(sta->key, new);
	} else {
		WARN_ON(new && key && new->conf.keyidx != key->conf.keyidx);

		if (key)
			idx = key->conf.keyidx;
		else
			idx = new->conf.keyidx;

		defkey = key && sdata->default_key == key;

		if (defkey && !new)
			ieee80211_set_default_key(sdata, -1);

		rcu_assign_pointer(sdata->keys[idx], new);

		if (defkey && new)
			ieee80211_set_default_key(sdata, new->conf.keyidx);
	}

	if (key) {
		ieee80211_key_mark_hw_accel_off(key);
		list_del(&key->list);
	}
}

void ieee80211_key_link(struct ieee80211_key *key,
			struct ieee80211_sub_if_data *sdata,
			struct sta_info *sta)
{
	struct ieee80211_key *old_key;
	int idx;

	ASSERT_RTNL();
	might_sleep();

	BUG_ON(!sdata);
	BUG_ON(!key);

	idx = key->conf.keyidx;
	key->local = sdata->local;
	key->sdata = sdata;
	key->sta = sta;

	ieee80211_debugfs_key_add(key->local, key);

	if (sta) {
		ieee80211_debugfs_key_sta_link(key, sta);

		/*
		 * some hardware cannot handle TKIP with QoS, so
		 * we indicate whether QoS could be in use.
		 */
		if (sta->flags & WLAN_STA_WME)
			key->conf.flags |= IEEE80211_KEY_FLAG_WMM_STA;
	} else {
		if (sdata->vif.type == IEEE80211_IF_TYPE_STA) {
			struct sta_info *ap;

			/* same here, the AP could be using QoS */
			ap = sta_info_get(key->local, key->sdata->u.sta.bssid);
			if (ap) {
				if (ap->flags & WLAN_STA_WME)
					key->conf.flags |=
						IEEE80211_KEY_FLAG_WMM_STA;
				sta_info_put(ap);
			}
		}
	}

	if (sta)
		old_key = sta->key;
	else
		old_key = sdata->keys[idx];

	__ieee80211_key_replace(sdata, sta, old_key, key);

	list_add(&key->list, &sdata->key_list);

	synchronize_rcu();

	ieee80211_key_free(old_key);
	ieee80211_key_enable_hw_accel(key);
}

void ieee80211_key_free(struct ieee80211_key *key)
{
	ASSERT_RTNL();
	might_sleep();

	if (!key)
		return;

	if (key->sdata) {
		/*
		 * Replace key with nothingness.
		 *
		 * Because other code may have key reference (RCU protected)
		 * right now, we then wait for a grace period before freeing
		 * it.
		 */
		__ieee80211_key_replace(key->sdata, key->sta, key, NULL);

		synchronize_rcu();

		/*
		 * Remove from hwaccel if appropriate, this will
		 * only happen when the key is actually unlinked,
		 * it will already be done when the key was replaced.
		 */
		ieee80211_key_disable_hw_accel(key);
	}

	if (key->conf.alg == ALG_CCMP)
		ieee80211_aes_key_free(key->u.ccmp.tfm);
	ieee80211_debugfs_key_remove(key);

	kfree(key);
}

void ieee80211_set_default_key(struct ieee80211_sub_if_data *sdata, int idx)
{
	struct ieee80211_key *key = NULL;

	if (idx >= 0 && idx < NUM_DEFAULT_KEYS)
		key = sdata->keys[idx];

	if (sdata->default_key != key) {
		ieee80211_debugfs_key_remove_default(sdata);

		rcu_assign_pointer(sdata->default_key, key);

		if (sdata->default_key)
			ieee80211_debugfs_key_add_default(sdata);
	}
}

void ieee80211_free_keys(struct ieee80211_sub_if_data *sdata)
{
	struct ieee80211_key *key, *tmp;
	LIST_HEAD(tmp_list);

	ASSERT_RTNL();
	might_sleep();

	list_for_each_entry_safe(key, tmp, &sdata->key_list, list)
		ieee80211_key_free(key);
}

void ieee80211_enable_keys(struct ieee80211_sub_if_data *sdata)
{
	struct ieee80211_key *key;

	ASSERT_RTNL();
	might_sleep();

	if (WARN_ON(!netif_running(sdata->dev)))
		return;

	list_for_each_entry(key, &sdata->key_list, list)
		ieee80211_key_enable_hw_accel(key);
}

void ieee80211_disable_keys(struct ieee80211_sub_if_data *sdata)
{
	struct ieee80211_key *key;

	ASSERT_RTNL();
	might_sleep();

	list_for_each_entry(key, &sdata->key_list, list)
		ieee80211_key_disable_hw_accel(key);
}