ARM: mmp: fix potential NULL dereference
[linux/fpc-iii.git] / net / mac80211 / key.c
blob7ae678ba5d679dbd40fc7c199c499ed82228757f
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>
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.
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 <linux/export.h>
19 #include <net/mac80211.h>
20 #include <asm/unaligned.h>
21 #include "ieee80211_i.h"
22 #include "driver-ops.h"
23 #include "debugfs_key.h"
24 #include "aes_ccm.h"
25 #include "aes_cmac.h"
28 /**
29 * DOC: Key handling basics
31 * Key handling in mac80211 is done based on per-interface (sub_if_data)
32 * keys and per-station keys. Since each station belongs to an interface,
33 * each station key also belongs to that interface.
35 * Hardware acceleration is done on a best-effort basis for algorithms
36 * that are implemented in software, for each key the hardware is asked
37 * to enable that key for offloading but if it cannot do that the key is
38 * simply kept for software encryption (unless it is for an algorithm
39 * that isn't implemented in software).
40 * There is currently no way of knowing whether a key is handled in SW
41 * or HW except by looking into debugfs.
43 * All key management is internally protected by a mutex. Within all
44 * other parts of mac80211, key references are, just as STA structure
45 * references, protected by RCU. Note, however, that some things are
46 * unprotected, namely the key->sta dereferences within the hardware
47 * acceleration functions. This means that sta_info_destroy() must
48 * remove the key which waits for an RCU grace period.
51 static const u8 bcast_addr[ETH_ALEN] = { 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF };
53 static void assert_key_lock(struct ieee80211_local *local)
55 lockdep_assert_held(&local->key_mtx);
58 static void increment_tailroom_need_count(struct ieee80211_sub_if_data *sdata)
61 * When this count is zero, SKB resizing for allocating tailroom
62 * for IV or MMIC is skipped. But, this check has created two race
63 * cases in xmit path while transiting from zero count to one:
65 * 1. SKB resize was skipped because no key was added but just before
66 * the xmit key is added and SW encryption kicks off.
68 * 2. SKB resize was skipped because all the keys were hw planted but
69 * just before xmit one of the key is deleted and SW encryption kicks
70 * off.
72 * In both the above case SW encryption will find not enough space for
73 * tailroom and exits with WARN_ON. (See WARN_ONs at wpa.c)
75 * Solution has been explained at
76 * http://mid.gmane.org/1308590980.4322.19.camel@jlt3.sipsolutions.net
79 if (!sdata->crypto_tx_tailroom_needed_cnt++) {
81 * Flush all XMIT packets currently using HW encryption or no
82 * encryption at all if the count transition is from 0 -> 1.
84 synchronize_net();
88 static int ieee80211_key_enable_hw_accel(struct ieee80211_key *key)
90 struct ieee80211_sub_if_data *sdata;
91 struct sta_info *sta;
92 int ret;
94 might_sleep();
96 if (!key->local->ops->set_key)
97 goto out_unsupported;
99 assert_key_lock(key->local);
101 sta = key->sta;
104 * If this is a per-STA GTK, check if it
105 * is supported; if not, return.
107 if (sta && !(key->conf.flags & IEEE80211_KEY_FLAG_PAIRWISE) &&
108 !(key->local->hw.flags & IEEE80211_HW_SUPPORTS_PER_STA_GTK))
109 goto out_unsupported;
111 if (sta && !sta->uploaded)
112 goto out_unsupported;
114 sdata = key->sdata;
115 if (sdata->vif.type == NL80211_IFTYPE_AP_VLAN) {
117 * The driver doesn't know anything about VLAN interfaces.
118 * Hence, don't send GTKs for VLAN interfaces to the driver.
120 if (!(key->conf.flags & IEEE80211_KEY_FLAG_PAIRWISE))
121 goto out_unsupported;
124 ret = drv_set_key(key->local, SET_KEY, sdata,
125 sta ? &sta->sta : NULL, &key->conf);
127 if (!ret) {
128 key->flags |= KEY_FLAG_UPLOADED_TO_HARDWARE;
130 if (!((key->conf.flags & IEEE80211_KEY_FLAG_GENERATE_MMIC) ||
131 (key->conf.flags & IEEE80211_KEY_FLAG_GENERATE_IV) ||
132 (key->conf.flags & IEEE80211_KEY_FLAG_PUT_IV_SPACE)))
133 sdata->crypto_tx_tailroom_needed_cnt--;
135 WARN_ON((key->conf.flags & IEEE80211_KEY_FLAG_PUT_IV_SPACE) &&
136 (key->conf.flags & IEEE80211_KEY_FLAG_GENERATE_IV));
138 return 0;
141 if (ret != -ENOSPC && ret != -EOPNOTSUPP)
142 sdata_err(sdata,
143 "failed to set key (%d, %pM) to hardware (%d)\n",
144 key->conf.keyidx,
145 sta ? sta->sta.addr : bcast_addr, ret);
147 out_unsupported:
148 switch (key->conf.cipher) {
149 case WLAN_CIPHER_SUITE_WEP40:
150 case WLAN_CIPHER_SUITE_WEP104:
151 case WLAN_CIPHER_SUITE_TKIP:
152 case WLAN_CIPHER_SUITE_CCMP:
153 case WLAN_CIPHER_SUITE_AES_CMAC:
154 /* all of these we can do in software */
155 return 0;
156 default:
157 return -EINVAL;
161 static void ieee80211_key_disable_hw_accel(struct ieee80211_key *key)
163 struct ieee80211_sub_if_data *sdata;
164 struct sta_info *sta;
165 int ret;
167 might_sleep();
169 if (!key || !key->local->ops->set_key)
170 return;
172 assert_key_lock(key->local);
174 if (!(key->flags & KEY_FLAG_UPLOADED_TO_HARDWARE))
175 return;
177 sta = key->sta;
178 sdata = key->sdata;
180 if (!((key->conf.flags & IEEE80211_KEY_FLAG_GENERATE_MMIC) ||
181 (key->conf.flags & IEEE80211_KEY_FLAG_GENERATE_IV) ||
182 (key->conf.flags & IEEE80211_KEY_FLAG_PUT_IV_SPACE)))
183 increment_tailroom_need_count(sdata);
185 ret = drv_set_key(key->local, DISABLE_KEY, sdata,
186 sta ? &sta->sta : NULL, &key->conf);
188 if (ret)
189 sdata_err(sdata,
190 "failed to remove key (%d, %pM) from hardware (%d)\n",
191 key->conf.keyidx,
192 sta ? sta->sta.addr : bcast_addr, ret);
194 key->flags &= ~KEY_FLAG_UPLOADED_TO_HARDWARE;
197 static void __ieee80211_set_default_key(struct ieee80211_sub_if_data *sdata,
198 int idx, bool uni, bool multi)
200 struct ieee80211_key *key = NULL;
202 assert_key_lock(sdata->local);
204 if (idx >= 0 && idx < NUM_DEFAULT_KEYS)
205 key = key_mtx_dereference(sdata->local, sdata->keys[idx]);
207 if (uni)
208 rcu_assign_pointer(sdata->default_unicast_key, key);
209 if (multi)
210 rcu_assign_pointer(sdata->default_multicast_key, key);
212 ieee80211_debugfs_key_update_default(sdata);
215 void ieee80211_set_default_key(struct ieee80211_sub_if_data *sdata, int idx,
216 bool uni, bool multi)
218 mutex_lock(&sdata->local->key_mtx);
219 __ieee80211_set_default_key(sdata, idx, uni, multi);
220 mutex_unlock(&sdata->local->key_mtx);
223 static void
224 __ieee80211_set_default_mgmt_key(struct ieee80211_sub_if_data *sdata, int idx)
226 struct ieee80211_key *key = NULL;
228 assert_key_lock(sdata->local);
230 if (idx >= NUM_DEFAULT_KEYS &&
231 idx < NUM_DEFAULT_KEYS + NUM_DEFAULT_MGMT_KEYS)
232 key = key_mtx_dereference(sdata->local, sdata->keys[idx]);
234 rcu_assign_pointer(sdata->default_mgmt_key, key);
236 ieee80211_debugfs_key_update_default(sdata);
239 void ieee80211_set_default_mgmt_key(struct ieee80211_sub_if_data *sdata,
240 int idx)
242 mutex_lock(&sdata->local->key_mtx);
243 __ieee80211_set_default_mgmt_key(sdata, idx);
244 mutex_unlock(&sdata->local->key_mtx);
248 static void __ieee80211_key_replace(struct ieee80211_sub_if_data *sdata,
249 struct sta_info *sta,
250 bool pairwise,
251 struct ieee80211_key *old,
252 struct ieee80211_key *new)
254 int idx;
255 bool defunikey, defmultikey, defmgmtkey;
257 if (new)
258 list_add_tail(&new->list, &sdata->key_list);
260 if (sta && pairwise) {
261 rcu_assign_pointer(sta->ptk, new);
262 } else if (sta) {
263 if (old)
264 idx = old->conf.keyidx;
265 else
266 idx = new->conf.keyidx;
267 rcu_assign_pointer(sta->gtk[idx], new);
268 } else {
269 WARN_ON(new && old && new->conf.keyidx != old->conf.keyidx);
271 if (old)
272 idx = old->conf.keyidx;
273 else
274 idx = new->conf.keyidx;
276 defunikey = old &&
277 old == key_mtx_dereference(sdata->local,
278 sdata->default_unicast_key);
279 defmultikey = old &&
280 old == key_mtx_dereference(sdata->local,
281 sdata->default_multicast_key);
282 defmgmtkey = old &&
283 old == key_mtx_dereference(sdata->local,
284 sdata->default_mgmt_key);
286 if (defunikey && !new)
287 __ieee80211_set_default_key(sdata, -1, true, false);
288 if (defmultikey && !new)
289 __ieee80211_set_default_key(sdata, -1, false, true);
290 if (defmgmtkey && !new)
291 __ieee80211_set_default_mgmt_key(sdata, -1);
293 rcu_assign_pointer(sdata->keys[idx], new);
294 if (defunikey && new)
295 __ieee80211_set_default_key(sdata, new->conf.keyidx,
296 true, false);
297 if (defmultikey && new)
298 __ieee80211_set_default_key(sdata, new->conf.keyidx,
299 false, true);
300 if (defmgmtkey && new)
301 __ieee80211_set_default_mgmt_key(sdata,
302 new->conf.keyidx);
305 if (old)
306 list_del(&old->list);
309 struct ieee80211_key *ieee80211_key_alloc(u32 cipher, int idx, size_t key_len,
310 const u8 *key_data,
311 size_t seq_len, const u8 *seq)
313 struct ieee80211_key *key;
314 int i, j, err;
316 BUG_ON(idx < 0 || idx >= NUM_DEFAULT_KEYS + NUM_DEFAULT_MGMT_KEYS);
318 key = kzalloc(sizeof(struct ieee80211_key) + key_len, GFP_KERNEL);
319 if (!key)
320 return ERR_PTR(-ENOMEM);
323 * Default to software encryption; we'll later upload the
324 * key to the hardware if possible.
326 key->conf.flags = 0;
327 key->flags = 0;
329 key->conf.cipher = cipher;
330 key->conf.keyidx = idx;
331 key->conf.keylen = key_len;
332 switch (cipher) {
333 case WLAN_CIPHER_SUITE_WEP40:
334 case WLAN_CIPHER_SUITE_WEP104:
335 key->conf.iv_len = WEP_IV_LEN;
336 key->conf.icv_len = WEP_ICV_LEN;
337 break;
338 case WLAN_CIPHER_SUITE_TKIP:
339 key->conf.iv_len = TKIP_IV_LEN;
340 key->conf.icv_len = TKIP_ICV_LEN;
341 if (seq) {
342 for (i = 0; i < NUM_RX_DATA_QUEUES; i++) {
343 key->u.tkip.rx[i].iv32 =
344 get_unaligned_le32(&seq[2]);
345 key->u.tkip.rx[i].iv16 =
346 get_unaligned_le16(seq);
349 spin_lock_init(&key->u.tkip.txlock);
350 break;
351 case WLAN_CIPHER_SUITE_CCMP:
352 key->conf.iv_len = CCMP_HDR_LEN;
353 key->conf.icv_len = CCMP_MIC_LEN;
354 if (seq) {
355 for (i = 0; i < NUM_RX_DATA_QUEUES + 1; i++)
356 for (j = 0; j < CCMP_PN_LEN; j++)
357 key->u.ccmp.rx_pn[i][j] =
358 seq[CCMP_PN_LEN - j - 1];
361 * Initialize AES key state here as an optimization so that
362 * it does not need to be initialized for every packet.
364 key->u.ccmp.tfm = ieee80211_aes_key_setup_encrypt(key_data);
365 if (IS_ERR(key->u.ccmp.tfm)) {
366 err = PTR_ERR(key->u.ccmp.tfm);
367 kfree(key);
368 return ERR_PTR(err);
370 break;
371 case WLAN_CIPHER_SUITE_AES_CMAC:
372 key->conf.iv_len = 0;
373 key->conf.icv_len = sizeof(struct ieee80211_mmie);
374 if (seq)
375 for (j = 0; j < 6; j++)
376 key->u.aes_cmac.rx_pn[j] = seq[6 - j - 1];
378 * Initialize AES key state here as an optimization so that
379 * it does not need to be initialized for every packet.
381 key->u.aes_cmac.tfm =
382 ieee80211_aes_cmac_key_setup(key_data);
383 if (IS_ERR(key->u.aes_cmac.tfm)) {
384 err = PTR_ERR(key->u.aes_cmac.tfm);
385 kfree(key);
386 return ERR_PTR(err);
388 break;
390 memcpy(key->conf.key, key_data, key_len);
391 INIT_LIST_HEAD(&key->list);
393 return key;
396 static void __ieee80211_key_destroy(struct ieee80211_key *key)
398 if (!key)
399 return;
402 * Synchronize so the TX path can no longer be using
403 * this key before we free/remove it.
405 synchronize_rcu();
407 if (key->local)
408 ieee80211_key_disable_hw_accel(key);
410 if (key->conf.cipher == WLAN_CIPHER_SUITE_CCMP)
411 ieee80211_aes_key_free(key->u.ccmp.tfm);
412 if (key->conf.cipher == WLAN_CIPHER_SUITE_AES_CMAC)
413 ieee80211_aes_cmac_key_free(key->u.aes_cmac.tfm);
414 if (key->local) {
415 ieee80211_debugfs_key_remove(key);
416 key->sdata->crypto_tx_tailroom_needed_cnt--;
419 kfree(key);
422 int ieee80211_key_link(struct ieee80211_key *key,
423 struct ieee80211_sub_if_data *sdata,
424 struct sta_info *sta)
426 struct ieee80211_key *old_key;
427 int idx, ret;
428 bool pairwise;
430 BUG_ON(!sdata);
431 BUG_ON(!key);
433 pairwise = key->conf.flags & IEEE80211_KEY_FLAG_PAIRWISE;
434 idx = key->conf.keyidx;
435 key->local = sdata->local;
436 key->sdata = sdata;
437 key->sta = sta;
439 if (sta) {
441 * some hardware cannot handle TKIP with QoS, so
442 * we indicate whether QoS could be in use.
444 if (test_sta_flag(sta, WLAN_STA_WME))
445 key->conf.flags |= IEEE80211_KEY_FLAG_WMM_STA;
446 } else {
447 if (sdata->vif.type == NL80211_IFTYPE_STATION) {
448 struct sta_info *ap;
451 * We're getting a sta pointer in, so must be under
452 * appropriate locking for sta_info_get().
455 /* same here, the AP could be using QoS */
456 ap = sta_info_get(key->sdata, key->sdata->u.mgd.bssid);
457 if (ap) {
458 if (test_sta_flag(ap, WLAN_STA_WME))
459 key->conf.flags |=
460 IEEE80211_KEY_FLAG_WMM_STA;
465 mutex_lock(&sdata->local->key_mtx);
467 if (sta && pairwise)
468 old_key = key_mtx_dereference(sdata->local, sta->ptk);
469 else if (sta)
470 old_key = key_mtx_dereference(sdata->local, sta->gtk[idx]);
471 else
472 old_key = key_mtx_dereference(sdata->local, sdata->keys[idx]);
474 increment_tailroom_need_count(sdata);
476 __ieee80211_key_replace(sdata, sta, pairwise, old_key, key);
477 __ieee80211_key_destroy(old_key);
479 ieee80211_debugfs_key_add(key);
481 ret = ieee80211_key_enable_hw_accel(key);
483 mutex_unlock(&sdata->local->key_mtx);
485 return ret;
488 void __ieee80211_key_free(struct ieee80211_key *key)
490 if (!key)
491 return;
494 * Replace key with nothingness if it was ever used.
496 if (key->sdata)
497 __ieee80211_key_replace(key->sdata, key->sta,
498 key->conf.flags & IEEE80211_KEY_FLAG_PAIRWISE,
499 key, NULL);
500 __ieee80211_key_destroy(key);
503 void ieee80211_key_free(struct ieee80211_local *local,
504 struct ieee80211_key *key)
506 mutex_lock(&local->key_mtx);
507 __ieee80211_key_free(key);
508 mutex_unlock(&local->key_mtx);
511 void ieee80211_enable_keys(struct ieee80211_sub_if_data *sdata)
513 struct ieee80211_key *key;
515 ASSERT_RTNL();
517 if (WARN_ON(!ieee80211_sdata_running(sdata)))
518 return;
520 mutex_lock(&sdata->local->key_mtx);
522 sdata->crypto_tx_tailroom_needed_cnt = 0;
524 list_for_each_entry(key, &sdata->key_list, list) {
525 increment_tailroom_need_count(sdata);
526 ieee80211_key_enable_hw_accel(key);
529 mutex_unlock(&sdata->local->key_mtx);
532 void ieee80211_iter_keys(struct ieee80211_hw *hw,
533 struct ieee80211_vif *vif,
534 void (*iter)(struct ieee80211_hw *hw,
535 struct ieee80211_vif *vif,
536 struct ieee80211_sta *sta,
537 struct ieee80211_key_conf *key,
538 void *data),
539 void *iter_data)
541 struct ieee80211_local *local = hw_to_local(hw);
542 struct ieee80211_key *key;
543 struct ieee80211_sub_if_data *sdata;
545 ASSERT_RTNL();
547 mutex_lock(&local->key_mtx);
548 if (vif) {
549 sdata = vif_to_sdata(vif);
550 list_for_each_entry(key, &sdata->key_list, list)
551 iter(hw, &sdata->vif,
552 key->sta ? &key->sta->sta : NULL,
553 &key->conf, iter_data);
554 } else {
555 list_for_each_entry(sdata, &local->interfaces, list)
556 list_for_each_entry(key, &sdata->key_list, list)
557 iter(hw, &sdata->vif,
558 key->sta ? &key->sta->sta : NULL,
559 &key->conf, iter_data);
561 mutex_unlock(&local->key_mtx);
563 EXPORT_SYMBOL(ieee80211_iter_keys);
565 void ieee80211_disable_keys(struct ieee80211_sub_if_data *sdata)
567 struct ieee80211_key *key;
569 ASSERT_RTNL();
571 mutex_lock(&sdata->local->key_mtx);
573 list_for_each_entry(key, &sdata->key_list, list)
574 ieee80211_key_disable_hw_accel(key);
576 mutex_unlock(&sdata->local->key_mtx);
579 void ieee80211_free_keys(struct ieee80211_sub_if_data *sdata)
581 struct ieee80211_key *key, *tmp;
583 mutex_lock(&sdata->local->key_mtx);
585 ieee80211_debugfs_key_remove_mgmt_default(sdata);
587 list_for_each_entry_safe(key, tmp, &sdata->key_list, list)
588 __ieee80211_key_free(key);
590 ieee80211_debugfs_key_update_default(sdata);
592 mutex_unlock(&sdata->local->key_mtx);
596 void ieee80211_gtk_rekey_notify(struct ieee80211_vif *vif, const u8 *bssid,
597 const u8 *replay_ctr, gfp_t gfp)
599 struct ieee80211_sub_if_data *sdata = vif_to_sdata(vif);
601 trace_api_gtk_rekey_notify(sdata, bssid, replay_ctr);
603 cfg80211_gtk_rekey_notify(sdata->dev, bssid, replay_ctr, gfp);
605 EXPORT_SYMBOL_GPL(ieee80211_gtk_rekey_notify);
607 void ieee80211_get_key_tx_seq(struct ieee80211_key_conf *keyconf,
608 struct ieee80211_key_seq *seq)
610 struct ieee80211_key *key;
611 u64 pn64;
613 if (WARN_ON(!(keyconf->flags & IEEE80211_KEY_FLAG_GENERATE_IV)))
614 return;
616 key = container_of(keyconf, struct ieee80211_key, conf);
618 switch (key->conf.cipher) {
619 case WLAN_CIPHER_SUITE_TKIP:
620 seq->tkip.iv32 = key->u.tkip.tx.iv32;
621 seq->tkip.iv16 = key->u.tkip.tx.iv16;
622 break;
623 case WLAN_CIPHER_SUITE_CCMP:
624 pn64 = atomic64_read(&key->u.ccmp.tx_pn);
625 seq->ccmp.pn[5] = pn64;
626 seq->ccmp.pn[4] = pn64 >> 8;
627 seq->ccmp.pn[3] = pn64 >> 16;
628 seq->ccmp.pn[2] = pn64 >> 24;
629 seq->ccmp.pn[1] = pn64 >> 32;
630 seq->ccmp.pn[0] = pn64 >> 40;
631 break;
632 case WLAN_CIPHER_SUITE_AES_CMAC:
633 pn64 = atomic64_read(&key->u.aes_cmac.tx_pn);
634 seq->ccmp.pn[5] = pn64;
635 seq->ccmp.pn[4] = pn64 >> 8;
636 seq->ccmp.pn[3] = pn64 >> 16;
637 seq->ccmp.pn[2] = pn64 >> 24;
638 seq->ccmp.pn[1] = pn64 >> 32;
639 seq->ccmp.pn[0] = pn64 >> 40;
640 break;
641 default:
642 WARN_ON(1);
645 EXPORT_SYMBOL(ieee80211_get_key_tx_seq);
647 void ieee80211_get_key_rx_seq(struct ieee80211_key_conf *keyconf,
648 int tid, struct ieee80211_key_seq *seq)
650 struct ieee80211_key *key;
651 const u8 *pn;
653 key = container_of(keyconf, struct ieee80211_key, conf);
655 switch (key->conf.cipher) {
656 case WLAN_CIPHER_SUITE_TKIP:
657 if (WARN_ON(tid < 0 || tid >= NUM_RX_DATA_QUEUES))
658 return;
659 seq->tkip.iv32 = key->u.tkip.rx[tid].iv32;
660 seq->tkip.iv16 = key->u.tkip.rx[tid].iv16;
661 break;
662 case WLAN_CIPHER_SUITE_CCMP:
663 if (WARN_ON(tid < -1 || tid >= NUM_RX_DATA_QUEUES))
664 return;
665 if (tid < 0)
666 pn = key->u.ccmp.rx_pn[NUM_RX_DATA_QUEUES];
667 else
668 pn = key->u.ccmp.rx_pn[tid];
669 memcpy(seq->ccmp.pn, pn, CCMP_PN_LEN);
670 break;
671 case WLAN_CIPHER_SUITE_AES_CMAC:
672 if (WARN_ON(tid != 0))
673 return;
674 pn = key->u.aes_cmac.rx_pn;
675 memcpy(seq->aes_cmac.pn, pn, CMAC_PN_LEN);
676 break;
679 EXPORT_SYMBOL(ieee80211_get_key_rx_seq);