1 /*
2 * Copyright 2002-2005, Instant802 Networks, Inc.
3 * Copyright 2005-2006, Devicescape Software, Inc.
4 * Copyright 2006-2007 Jiri Benc <jbenc@suse.cz>
5 * Copyright 2007-2008 Johannes Berg <johannes@sipsolutions.net>
6 *
7 * This program is free software; you can redistribute it and/or modify
8 * it under the terms of the GNU General Public License version 2 as
9 * published by the Free Software Foundation.
10 */
11
12 #include <linux/if_ether.h>
13 #include <linux/etherdevice.h>
14 #include <linux/list.h>
15 #include <linux/rcupdate.h>
16 #include <linux/rtnetlink.h>
17 #include <linux/slab.h>
18 #include <net/mac80211.h>
19 #include "ieee80211_i.h"
20 #include "driver-ops.h"
21 #include "debugfs_key.h"
22 #include "aes_ccm.h"
23 #include "aes_cmac.h"
24
25
26 /**
27 * DOC: Key handling basics
28 *
29 * Key handling in mac80211 is done based on per-interface (sub_if_data)
30 * keys and per-station keys. Since each station belongs to an interface,
31 * each station key also belongs to that interface.
32 *
33 * Hardware acceleration is done on a best-effort basis for algorithms
34 * that are implemented in software, for each key the hardware is asked
35 * to enable that key for offloading but if it cannot do that the key is
36 * simply kept for software encryption (unless it is for an algorithm
37 * that isn't implemented in software).
38 * There is currently no way of knowing whether a key is handled in SW
39 * or HW except by looking into debugfs.
40 *
41 * All key management is internally protected by a mutex. Within all
42 * other parts of mac80211, key references are, just as STA structure
43 * references, protected by RCU. Note, however, that some things are
44 * unprotected, namely the key->sta dereferences within the hardware
45 * acceleration functions. This means that sta_info_destroy() must
46 * remove the key which waits for an RCU grace period.
47 */
48
49 static const u8 bcast_addr[ETH_ALEN] = { 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF };
50
assert_key_lock(struct ieee80211_local * local)51 static void assert_key_lock(struct ieee80211_local *local)
52 {
53 lockdep_assert_held(&local->key_mtx);
54 }
55
get_sta_for_key(struct ieee80211_key * key)56 static struct ieee80211_sta *get_sta_for_key(struct ieee80211_key *key)
57 {
58 if (key->sta)
59 return &key->sta->sta;
60
61 return NULL;
62 }
63
ieee80211_key_enable_hw_accel(struct ieee80211_key * key)64 static int ieee80211_key_enable_hw_accel(struct ieee80211_key *key)
65 {
66 struct ieee80211_sub_if_data *sdata;
67 struct ieee80211_sta *sta;
68 int ret;
69
70 might_sleep();
71
72 if (!key->local->ops->set_key)
73 goto out_unsupported;
74
75 assert_key_lock(key->local);
76
77 sta = get_sta_for_key(key);
78
79 /*
80 * If this is a per-STA GTK, check if it
81 * is supported; if not, return.
82 */
83 if (sta && !(key->conf.flags & IEEE80211_KEY_FLAG_PAIRWISE) &&
84 !(key->local->hw.flags & IEEE80211_HW_SUPPORTS_PER_STA_GTK))
85 goto out_unsupported;
86
87 sdata = key->sdata;
88 if (sdata->vif.type == NL80211_IFTYPE_AP_VLAN) {
89 /*
90 * The driver doesn't know anything about VLAN interfaces.
91 * Hence, don't send GTKs for VLAN interfaces to the driver.
92 */
93 if (!(key->conf.flags & IEEE80211_KEY_FLAG_PAIRWISE))
94 goto out_unsupported;
95 sdata = container_of(sdata->bss,
96 struct ieee80211_sub_if_data,
97 u.ap);
98 }
99
100 ret = drv_set_key(key->local, SET_KEY, sdata, sta, &key->conf);
101
102 if (!ret) {
103 key->flags |= KEY_FLAG_UPLOADED_TO_HARDWARE;
104 return 0;
105 }
106
107 if (ret != -ENOSPC && ret != -EOPNOTSUPP)
108 wiphy_err(key->local->hw.wiphy,
109 "failed to set key (%d, %pM) to hardware (%d)\n",
110 key->conf.keyidx, sta ? sta->addr : bcast_addr, ret);
111
112 out_unsupported:
113 switch (key->conf.cipher) {
114 case WLAN_CIPHER_SUITE_WEP40:
115 case WLAN_CIPHER_SUITE_WEP104:
116 case WLAN_CIPHER_SUITE_TKIP:
117 case WLAN_CIPHER_SUITE_CCMP:
118 case WLAN_CIPHER_SUITE_AES_CMAC:
119 /* all of these we can do in software */
120 return 0;
121 default:
122 return -EINVAL;
123 }
124 }
125
ieee80211_key_disable_hw_accel(struct ieee80211_key * key)126 static void ieee80211_key_disable_hw_accel(struct ieee80211_key *key)
127 {
128 struct ieee80211_sub_if_data *sdata;
129 struct ieee80211_sta *sta;
130 int ret;
131
132 might_sleep();
133
134 if (!key || !key->local->ops->set_key)
135 return;
136
137 assert_key_lock(key->local);
138
139 if (!(key->flags & KEY_FLAG_UPLOADED_TO_HARDWARE))
140 return;
141
142 sta = get_sta_for_key(key);
143 sdata = key->sdata;
144
145 if (sdata->vif.type == NL80211_IFTYPE_AP_VLAN)
146 sdata = container_of(sdata->bss,
147 struct ieee80211_sub_if_data,
148 u.ap);
149
150 ret = drv_set_key(key->local, DISABLE_KEY, sdata,
151 sta, &key->conf);
152
153 if (ret)
154 wiphy_err(key->local->hw.wiphy,
155 "failed to remove key (%d, %pM) from hardware (%d)\n",
156 key->conf.keyidx, sta ? sta->addr : bcast_addr, ret);
157
158 key->flags &= ~KEY_FLAG_UPLOADED_TO_HARDWARE;
159 }
160
ieee80211_key_removed(struct ieee80211_key_conf * key_conf)161 void ieee80211_key_removed(struct ieee80211_key_conf *key_conf)
162 {
163 struct ieee80211_key *key;
164
165 key = container_of(key_conf, struct ieee80211_key, conf);
166
167 might_sleep();
168 assert_key_lock(key->local);
169
170 key->flags &= ~KEY_FLAG_UPLOADED_TO_HARDWARE;
171
172 /*
173 * Flush TX path to avoid attempts to use this key
174 * after this function returns. Until then, drivers
175 * must be prepared to handle the key.
176 */
177 synchronize_rcu();
178 }
179 EXPORT_SYMBOL_GPL(ieee80211_key_removed);
180
__ieee80211_set_default_key(struct ieee80211_sub_if_data * sdata,int idx,bool uni,bool multi)181 static void __ieee80211_set_default_key(struct ieee80211_sub_if_data *sdata,
182 int idx, bool uni, bool multi)
183 {
184 struct ieee80211_key *key = NULL;
185
186 assert_key_lock(sdata->local);
187
188 if (idx >= 0 && idx < NUM_DEFAULT_KEYS)
189 key = sdata->keys[idx];
190
191 if (uni)
192 rcu_assign_pointer(sdata->default_unicast_key, key);
193 if (multi)
194 rcu_assign_pointer(sdata->default_multicast_key, key);
195
196 ieee80211_debugfs_key_update_default(sdata);
197 }
198
ieee80211_set_default_key(struct ieee80211_sub_if_data * sdata,int idx,bool uni,bool multi)199 void ieee80211_set_default_key(struct ieee80211_sub_if_data *sdata, int idx,
200 bool uni, bool multi)
201 {
202 mutex_lock(&sdata->local->key_mtx);
203 __ieee80211_set_default_key(sdata, idx, uni, multi);
204 mutex_unlock(&sdata->local->key_mtx);
205 }
206
207 static void
__ieee80211_set_default_mgmt_key(struct ieee80211_sub_if_data * sdata,int idx)208 __ieee80211_set_default_mgmt_key(struct ieee80211_sub_if_data *sdata, int idx)
209 {
210 struct ieee80211_key *key = NULL;
211
212 assert_key_lock(sdata->local);
213
214 if (idx >= NUM_DEFAULT_KEYS &&
215 idx < NUM_DEFAULT_KEYS + NUM_DEFAULT_MGMT_KEYS)
216 key = sdata->keys[idx];
217
218 rcu_assign_pointer(sdata->default_mgmt_key, key);
219
220 ieee80211_debugfs_key_update_default(sdata);
221 }
222
ieee80211_set_default_mgmt_key(struct ieee80211_sub_if_data * sdata,int idx)223 void ieee80211_set_default_mgmt_key(struct ieee80211_sub_if_data *sdata,
224 int idx)
225 {
226 mutex_lock(&sdata->local->key_mtx);
227 __ieee80211_set_default_mgmt_key(sdata, idx);
228 mutex_unlock(&sdata->local->key_mtx);
229 }
230
231
__ieee80211_key_replace(struct ieee80211_sub_if_data * sdata,struct sta_info * sta,bool pairwise,struct ieee80211_key * old,struct ieee80211_key * new)232 static void __ieee80211_key_replace(struct ieee80211_sub_if_data *sdata,
233 struct sta_info *sta,
234 bool pairwise,
235 struct ieee80211_key *old,
236 struct ieee80211_key *new)
237 {
238 int idx;
239 bool defunikey, defmultikey, defmgmtkey;
240
241 if (new)
242 list_add(&new->list, &sdata->key_list);
243
244 if (sta && pairwise) {
245 rcu_assign_pointer(sta->ptk, new);
246 } else if (sta) {
247 if (old)
248 idx = old->conf.keyidx;
249 else
250 idx = new->conf.keyidx;
251 rcu_assign_pointer(sta->gtk[idx], new);
252 } else {
253 WARN_ON(new && old && new->conf.keyidx != old->conf.keyidx);
254
255 if (old)
256 idx = old->conf.keyidx;
257 else
258 idx = new->conf.keyidx;
259
260 defunikey = old && sdata->default_unicast_key == old;
261 defmultikey = old && sdata->default_multicast_key == old;
262 defmgmtkey = old && sdata->default_mgmt_key == old;
263
264 if (defunikey && !new)
265 __ieee80211_set_default_key(sdata, -1, true, false);
266 if (defmultikey && !new)
267 __ieee80211_set_default_key(sdata, -1, false, true);
268 if (defmgmtkey && !new)
269 __ieee80211_set_default_mgmt_key(sdata, -1);
270
271 rcu_assign_pointer(sdata->keys[idx], new);
272 if (defunikey && new)
273 __ieee80211_set_default_key(sdata, new->conf.keyidx,
274 true, false);
275 if (defmultikey && new)
276 __ieee80211_set_default_key(sdata, new->conf.keyidx,
277 false, true);
278 if (defmgmtkey && new)
279 __ieee80211_set_default_mgmt_key(sdata,
280 new->conf.keyidx);
281 }
282
283 if (old)
284 list_del(&old->list);
285 }
286
ieee80211_key_alloc(u32 cipher,int idx,size_t key_len,const u8 * key_data,size_t seq_len,const u8 * seq)287 struct ieee80211_key *ieee80211_key_alloc(u32 cipher, int idx, size_t key_len,
288 const u8 *key_data,
289 size_t seq_len, const u8 *seq)
290 {
291 struct ieee80211_key *key;
292 int i, j, err;
293
294 BUG_ON(idx < 0 || idx >= NUM_DEFAULT_KEYS + NUM_DEFAULT_MGMT_KEYS);
295
296 key = kzalloc(sizeof(struct ieee80211_key) + key_len, GFP_KERNEL);
297 if (!key)
298 return ERR_PTR(-ENOMEM);
299
300 /*
301 * Default to software encryption; we'll later upload the
302 * key to the hardware if possible.
303 */
304 key->conf.flags = 0;
305 key->flags = 0;
306
307 key->conf.cipher = cipher;
308 key->conf.keyidx = idx;
309 key->conf.keylen = key_len;
310 switch (cipher) {
311 case WLAN_CIPHER_SUITE_WEP40:
312 case WLAN_CIPHER_SUITE_WEP104:
313 key->conf.iv_len = WEP_IV_LEN;
314 key->conf.icv_len = WEP_ICV_LEN;
315 break;
316 case WLAN_CIPHER_SUITE_TKIP:
317 key->conf.iv_len = TKIP_IV_LEN;
318 key->conf.icv_len = TKIP_ICV_LEN;
319 if (seq) {
320 for (i = 0; i < NUM_RX_DATA_QUEUES; i++) {
321 key->u.tkip.rx[i].iv32 =
322 get_unaligned_le32(&seq[2]);
323 key->u.tkip.rx[i].iv16 =
324 get_unaligned_le16(seq);
325 }
326 }
327 break;
328 case WLAN_CIPHER_SUITE_CCMP:
329 key->conf.iv_len = CCMP_HDR_LEN;
330 key->conf.icv_len = CCMP_MIC_LEN;
331 if (seq) {
332 for (i = 0; i < NUM_RX_DATA_QUEUES + 1; i++)
333 for (j = 0; j < CCMP_PN_LEN; j++)
334 key->u.ccmp.rx_pn[i][j] =
335 seq[CCMP_PN_LEN - j - 1];
336 }
337 /*
338 * Initialize AES key state here as an optimization so that
339 * it does not need to be initialized for every packet.
340 */
341 key->u.ccmp.tfm = ieee80211_aes_key_setup_encrypt(key_data);
342 if (IS_ERR(key->u.ccmp.tfm)) {
343 err = PTR_ERR(key->u.ccmp.tfm);
344 kfree(key);
345 return ERR_PTR(err);
346 }
347 break;
348 case WLAN_CIPHER_SUITE_AES_CMAC:
349 key->conf.iv_len = 0;
350 key->conf.icv_len = sizeof(struct ieee80211_mmie);
351 if (seq)
352 for (j = 0; j < 6; j++)
353 key->u.aes_cmac.rx_pn[j] = seq[6 - j - 1];
354 /*
355 * Initialize AES key state here as an optimization so that
356 * it does not need to be initialized for every packet.
357 */
358 key->u.aes_cmac.tfm =
359 ieee80211_aes_cmac_key_setup(key_data);
360 if (IS_ERR(key->u.aes_cmac.tfm)) {
361 err = PTR_ERR(key->u.aes_cmac.tfm);
362 kfree(key);
363 return ERR_PTR(err);
364 }
365 break;
366 }
367 memcpy(key->conf.key, key_data, key_len);
368 INIT_LIST_HEAD(&key->list);
369
370 return key;
371 }
372
__ieee80211_key_destroy(struct ieee80211_key * key)373 static void __ieee80211_key_destroy(struct ieee80211_key *key)
374 {
375 if (!key)
376 return;
377
378 /*
379 * Synchronize so the TX path can no longer be using
380 * this key before we free/remove it.
381 */
382 synchronize_rcu();
383
384 if (key->local)
385 ieee80211_key_disable_hw_accel(key);
386
387 if (key->conf.cipher == WLAN_CIPHER_SUITE_CCMP)
388 ieee80211_aes_key_free(key->u.ccmp.tfm);
389 if (key->conf.cipher == WLAN_CIPHER_SUITE_AES_CMAC)
390 ieee80211_aes_cmac_key_free(key->u.aes_cmac.tfm);
391 if (key->local)
392 ieee80211_debugfs_key_remove(key);
393
394 kfree(key);
395 }
396
ieee80211_key_link(struct ieee80211_key * key,struct ieee80211_sub_if_data * sdata,struct sta_info * sta)397 int ieee80211_key_link(struct ieee80211_key *key,
398 struct ieee80211_sub_if_data *sdata,
399 struct sta_info *sta)
400 {
401 struct ieee80211_key *old_key;
402 int idx, ret;
403 bool pairwise;
404
405 BUG_ON(!sdata);
406 BUG_ON(!key);
407
408 pairwise = key->conf.flags & IEEE80211_KEY_FLAG_PAIRWISE;
409 idx = key->conf.keyidx;
410 key->local = sdata->local;
411 key->sdata = sdata;
412 key->sta = sta;
413
414 if (sta) {
415 /*
416 * some hardware cannot handle TKIP with QoS, so
417 * we indicate whether QoS could be in use.
418 */
419 if (test_sta_flags(sta, WLAN_STA_WME))
420 key->conf.flags |= IEEE80211_KEY_FLAG_WMM_STA;
421 } else {
422 if (sdata->vif.type == NL80211_IFTYPE_STATION) {
423 struct sta_info *ap;
424
425 /*
426 * We're getting a sta pointer in, so must be under
427 * appropriate locking for sta_info_get().
428 */
429
430 /* same here, the AP could be using QoS */
431 ap = sta_info_get(key->sdata, key->sdata->u.mgd.bssid);
432 if (ap) {
433 if (test_sta_flags(ap, WLAN_STA_WME))
434 key->conf.flags |=
435 IEEE80211_KEY_FLAG_WMM_STA;
436 }
437 }
438 }
439
440 mutex_lock(&sdata->local->key_mtx);
441
442 if (sta && pairwise)
443 old_key = sta->ptk;
444 else if (sta)
445 old_key = sta->gtk[idx];
446 else
447 old_key = sdata->keys[idx];
448
449 __ieee80211_key_replace(sdata, sta, pairwise, old_key, key);
450 __ieee80211_key_destroy(old_key);
451
452 ieee80211_debugfs_key_add(key);
453
454 ret = ieee80211_key_enable_hw_accel(key);
455
456 mutex_unlock(&sdata->local->key_mtx);
457
458 return ret;
459 }
460
__ieee80211_key_free(struct ieee80211_key * key)461 static void __ieee80211_key_free(struct ieee80211_key *key)
462 {
463 /*
464 * Replace key with nothingness if it was ever used.
465 */
466 if (key->sdata)
467 __ieee80211_key_replace(key->sdata, key->sta,
468 key->conf.flags & IEEE80211_KEY_FLAG_PAIRWISE,
469 key, NULL);
470 __ieee80211_key_destroy(key);
471 }
472
ieee80211_key_free(struct ieee80211_local * local,struct ieee80211_key * key)473 void ieee80211_key_free(struct ieee80211_local *local,
474 struct ieee80211_key *key)
475 {
476 if (!key)
477 return;
478
479 mutex_lock(&local->key_mtx);
480 __ieee80211_key_free(key);
481 mutex_unlock(&local->key_mtx);
482 }
483
ieee80211_enable_keys(struct ieee80211_sub_if_data * sdata)484 void ieee80211_enable_keys(struct ieee80211_sub_if_data *sdata)
485 {
486 struct ieee80211_key *key;
487
488 ASSERT_RTNL();
489
490 if (WARN_ON(!ieee80211_sdata_running(sdata)))
491 return;
492
493 mutex_lock(&sdata->local->key_mtx);
494
495 list_for_each_entry(key, &sdata->key_list, list)
496 ieee80211_key_enable_hw_accel(key);
497
498 mutex_unlock(&sdata->local->key_mtx);
499 }
500
ieee80211_disable_keys(struct ieee80211_sub_if_data * sdata)501 void ieee80211_disable_keys(struct ieee80211_sub_if_data *sdata)
502 {
503 struct ieee80211_key *key;
504
505 ASSERT_RTNL();
506
507 mutex_lock(&sdata->local->key_mtx);
508
509 list_for_each_entry(key, &sdata->key_list, list)
510 ieee80211_key_disable_hw_accel(key);
511
512 mutex_unlock(&sdata->local->key_mtx);
513 }
514
ieee80211_free_keys(struct ieee80211_sub_if_data * sdata)515 void ieee80211_free_keys(struct ieee80211_sub_if_data *sdata)
516 {
517 struct ieee80211_key *key, *tmp;
518
519 mutex_lock(&sdata->local->key_mtx);
520
521 ieee80211_debugfs_key_remove_mgmt_default(sdata);
522
523 list_for_each_entry_safe(key, tmp, &sdata->key_list, list)
524 __ieee80211_key_free(key);
525
526 ieee80211_debugfs_key_update_default(sdata);
527
528 mutex_unlock(&sdata->local->key_mtx);
529 }
530