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 <net/mac80211.h>
19 #include "ieee80211_i.h"
20 #include "driver-ops.h"
21 #include "debugfs_key.h"
27 * DOC: Key handling basics
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.
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.
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.
49 static const u8 bcast_addr
[ETH_ALEN
] = { 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF };
51 static void assert_key_lock(struct ieee80211_local
*local
)
53 lockdep_assert_held(&local
->key_mtx
);
56 static struct ieee80211_sta
*get_sta_for_key(struct ieee80211_key
*key
)
59 return &key
->sta
->sta
;
64 static void increment_tailroom_need_count(struct ieee80211_sub_if_data
*sdata
)
67 * When this count is zero, SKB resizing for allocating tailroom
68 * for IV or MMIC is skipped. But, this check has created two race
69 * cases in xmit path while transiting from zero count to one:
71 * 1. SKB resize was skipped because no key was added but just before
72 * the xmit key is added and SW encryption kicks off.
74 * 2. SKB resize was skipped because all the keys were hw planted but
75 * just before xmit one of the key is deleted and SW encryption kicks
78 * In both the above case SW encryption will find not enough space for
79 * tailroom and exits with WARN_ON. (See WARN_ONs at wpa.c)
81 * Solution has been explained at
82 * http://mid.gmane.org/1308590980.4322.19.camel@jlt3.sipsolutions.net
85 if (!sdata
->crypto_tx_tailroom_needed_cnt
++) {
87 * Flush all XMIT packets currently using HW encryption or no
88 * encryption at all if the count transition is from 0 -> 1.
94 static int ieee80211_key_enable_hw_accel(struct ieee80211_key
*key
)
96 struct ieee80211_sub_if_data
*sdata
;
97 struct ieee80211_sta
*sta
;
102 if (!key
->local
->ops
->set_key
)
103 goto out_unsupported
;
105 assert_key_lock(key
->local
);
107 sta
= get_sta_for_key(key
);
110 * If this is a per-STA GTK, check if it
111 * is supported; if not, return.
113 if (sta
&& !(key
->conf
.flags
& IEEE80211_KEY_FLAG_PAIRWISE
) &&
114 !(key
->local
->hw
.flags
& IEEE80211_HW_SUPPORTS_PER_STA_GTK
))
115 goto out_unsupported
;
118 if (sdata
->vif
.type
== NL80211_IFTYPE_AP_VLAN
) {
120 * The driver doesn't know anything about VLAN interfaces.
121 * Hence, don't send GTKs for VLAN interfaces to the driver.
123 if (!(key
->conf
.flags
& IEEE80211_KEY_FLAG_PAIRWISE
))
124 goto out_unsupported
;
125 sdata
= container_of(sdata
->bss
,
126 struct ieee80211_sub_if_data
,
130 ret
= drv_set_key(key
->local
, SET_KEY
, sdata
, sta
, &key
->conf
);
133 key
->flags
|= KEY_FLAG_UPLOADED_TO_HARDWARE
;
135 if (!((key
->conf
.flags
& IEEE80211_KEY_FLAG_GENERATE_MMIC
) ||
136 (key
->conf
.flags
& IEEE80211_KEY_FLAG_GENERATE_IV
)))
137 sdata
->crypto_tx_tailroom_needed_cnt
--;
142 if (ret
!= -ENOSPC
&& ret
!= -EOPNOTSUPP
)
143 wiphy_err(key
->local
->hw
.wiphy
,
144 "failed to set key (%d, %pM) to hardware (%d)\n",
145 key
->conf
.keyidx
, sta
? sta
->addr
: bcast_addr
, ret
);
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 */
161 static void ieee80211_key_disable_hw_accel(struct ieee80211_key
*key
)
163 struct ieee80211_sub_if_data
*sdata
;
164 struct ieee80211_sta
*sta
;
169 if (!key
|| !key
->local
->ops
->set_key
)
172 assert_key_lock(key
->local
);
174 if (!(key
->flags
& KEY_FLAG_UPLOADED_TO_HARDWARE
))
177 sta
= get_sta_for_key(key
);
180 if (!((key
->conf
.flags
& IEEE80211_KEY_FLAG_GENERATE_MMIC
) ||
181 (key
->conf
.flags
& IEEE80211_KEY_FLAG_GENERATE_IV
)))
182 increment_tailroom_need_count(sdata
);
184 if (sdata
->vif
.type
== NL80211_IFTYPE_AP_VLAN
)
185 sdata
= container_of(sdata
->bss
,
186 struct ieee80211_sub_if_data
,
189 ret
= drv_set_key(key
->local
, DISABLE_KEY
, sdata
,
193 wiphy_err(key
->local
->hw
.wiphy
,
194 "failed to remove key (%d, %pM) from hardware (%d)\n",
195 key
->conf
.keyidx
, sta
? sta
->addr
: bcast_addr
, ret
);
197 key
->flags
&= ~KEY_FLAG_UPLOADED_TO_HARDWARE
;
200 void ieee80211_key_removed(struct ieee80211_key_conf
*key_conf
)
202 struct ieee80211_key
*key
;
204 key
= container_of(key_conf
, struct ieee80211_key
, conf
);
207 assert_key_lock(key
->local
);
209 key
->flags
&= ~KEY_FLAG_UPLOADED_TO_HARDWARE
;
212 * Flush TX path to avoid attempts to use this key
213 * after this function returns. Until then, drivers
214 * must be prepared to handle the key.
218 EXPORT_SYMBOL_GPL(ieee80211_key_removed
);
220 static void __ieee80211_set_default_key(struct ieee80211_sub_if_data
*sdata
,
221 int idx
, bool uni
, bool multi
)
223 struct ieee80211_key
*key
= NULL
;
225 assert_key_lock(sdata
->local
);
227 if (idx
>= 0 && idx
< NUM_DEFAULT_KEYS
)
228 key
= key_mtx_dereference(sdata
->local
, sdata
->keys
[idx
]);
231 rcu_assign_pointer(sdata
->default_unicast_key
, key
);
233 rcu_assign_pointer(sdata
->default_multicast_key
, key
);
235 ieee80211_debugfs_key_update_default(sdata
);
238 void ieee80211_set_default_key(struct ieee80211_sub_if_data
*sdata
, int idx
,
239 bool uni
, bool multi
)
241 mutex_lock(&sdata
->local
->key_mtx
);
242 __ieee80211_set_default_key(sdata
, idx
, uni
, multi
);
243 mutex_unlock(&sdata
->local
->key_mtx
);
247 __ieee80211_set_default_mgmt_key(struct ieee80211_sub_if_data
*sdata
, int idx
)
249 struct ieee80211_key
*key
= NULL
;
251 assert_key_lock(sdata
->local
);
253 if (idx
>= NUM_DEFAULT_KEYS
&&
254 idx
< NUM_DEFAULT_KEYS
+ NUM_DEFAULT_MGMT_KEYS
)
255 key
= key_mtx_dereference(sdata
->local
, sdata
->keys
[idx
]);
257 rcu_assign_pointer(sdata
->default_mgmt_key
, key
);
259 ieee80211_debugfs_key_update_default(sdata
);
262 void ieee80211_set_default_mgmt_key(struct ieee80211_sub_if_data
*sdata
,
265 mutex_lock(&sdata
->local
->key_mtx
);
266 __ieee80211_set_default_mgmt_key(sdata
, idx
);
267 mutex_unlock(&sdata
->local
->key_mtx
);
271 static void __ieee80211_key_replace(struct ieee80211_sub_if_data
*sdata
,
272 struct sta_info
*sta
,
274 struct ieee80211_key
*old
,
275 struct ieee80211_key
*new)
278 bool defunikey
, defmultikey
, defmgmtkey
;
281 list_add(&new->list
, &sdata
->key_list
);
283 if (sta
&& pairwise
) {
284 rcu_assign_pointer(sta
->ptk
, new);
287 idx
= old
->conf
.keyidx
;
289 idx
= new->conf
.keyidx
;
290 rcu_assign_pointer(sta
->gtk
[idx
], new);
292 WARN_ON(new && old
&& new->conf
.keyidx
!= old
->conf
.keyidx
);
295 idx
= old
->conf
.keyidx
;
297 idx
= new->conf
.keyidx
;
300 old
== key_mtx_dereference(sdata
->local
,
301 sdata
->default_unicast_key
);
303 old
== key_mtx_dereference(sdata
->local
,
304 sdata
->default_multicast_key
);
306 old
== key_mtx_dereference(sdata
->local
,
307 sdata
->default_mgmt_key
);
309 if (defunikey
&& !new)
310 __ieee80211_set_default_key(sdata
, -1, true, false);
311 if (defmultikey
&& !new)
312 __ieee80211_set_default_key(sdata
, -1, false, true);
313 if (defmgmtkey
&& !new)
314 __ieee80211_set_default_mgmt_key(sdata
, -1);
316 rcu_assign_pointer(sdata
->keys
[idx
], new);
317 if (defunikey
&& new)
318 __ieee80211_set_default_key(sdata
, new->conf
.keyidx
,
320 if (defmultikey
&& new)
321 __ieee80211_set_default_key(sdata
, new->conf
.keyidx
,
323 if (defmgmtkey
&& new)
324 __ieee80211_set_default_mgmt_key(sdata
,
329 list_del(&old
->list
);
332 struct ieee80211_key
*ieee80211_key_alloc(u32 cipher
, int idx
, size_t key_len
,
334 size_t seq_len
, const u8
*seq
)
336 struct ieee80211_key
*key
;
339 BUG_ON(idx
< 0 || idx
>= NUM_DEFAULT_KEYS
+ NUM_DEFAULT_MGMT_KEYS
);
341 key
= kzalloc(sizeof(struct ieee80211_key
) + key_len
, GFP_KERNEL
);
343 return ERR_PTR(-ENOMEM
);
346 * Default to software encryption; we'll later upload the
347 * key to the hardware if possible.
352 key
->conf
.cipher
= cipher
;
353 key
->conf
.keyidx
= idx
;
354 key
->conf
.keylen
= key_len
;
356 case WLAN_CIPHER_SUITE_WEP40
:
357 case WLAN_CIPHER_SUITE_WEP104
:
358 key
->conf
.iv_len
= WEP_IV_LEN
;
359 key
->conf
.icv_len
= WEP_ICV_LEN
;
361 case WLAN_CIPHER_SUITE_TKIP
:
362 key
->conf
.iv_len
= TKIP_IV_LEN
;
363 key
->conf
.icv_len
= TKIP_ICV_LEN
;
365 for (i
= 0; i
< NUM_RX_DATA_QUEUES
; i
++) {
366 key
->u
.tkip
.rx
[i
].iv32
=
367 get_unaligned_le32(&seq
[2]);
368 key
->u
.tkip
.rx
[i
].iv16
=
369 get_unaligned_le16(seq
);
373 case WLAN_CIPHER_SUITE_CCMP
:
374 key
->conf
.iv_len
= CCMP_HDR_LEN
;
375 key
->conf
.icv_len
= CCMP_MIC_LEN
;
377 for (i
= 0; i
< NUM_RX_DATA_QUEUES
+ 1; i
++)
378 for (j
= 0; j
< CCMP_PN_LEN
; j
++)
379 key
->u
.ccmp
.rx_pn
[i
][j
] =
380 seq
[CCMP_PN_LEN
- j
- 1];
383 * Initialize AES key state here as an optimization so that
384 * it does not need to be initialized for every packet.
386 key
->u
.ccmp
.tfm
= ieee80211_aes_key_setup_encrypt(key_data
);
387 if (IS_ERR(key
->u
.ccmp
.tfm
)) {
388 err
= PTR_ERR(key
->u
.ccmp
.tfm
);
393 case WLAN_CIPHER_SUITE_AES_CMAC
:
394 key
->conf
.iv_len
= 0;
395 key
->conf
.icv_len
= sizeof(struct ieee80211_mmie
);
397 for (j
= 0; j
< 6; j
++)
398 key
->u
.aes_cmac
.rx_pn
[j
] = seq
[6 - j
- 1];
400 * Initialize AES key state here as an optimization so that
401 * it does not need to be initialized for every packet.
403 key
->u
.aes_cmac
.tfm
=
404 ieee80211_aes_cmac_key_setup(key_data
);
405 if (IS_ERR(key
->u
.aes_cmac
.tfm
)) {
406 err
= PTR_ERR(key
->u
.aes_cmac
.tfm
);
412 memcpy(key
->conf
.key
, key_data
, key_len
);
413 INIT_LIST_HEAD(&key
->list
);
418 static void __ieee80211_key_destroy(struct ieee80211_key
*key
)
424 * Synchronize so the TX path can no longer be using
425 * this key before we free/remove it.
430 ieee80211_key_disable_hw_accel(key
);
432 if (key
->conf
.cipher
== WLAN_CIPHER_SUITE_CCMP
)
433 ieee80211_aes_key_free(key
->u
.ccmp
.tfm
);
434 if (key
->conf
.cipher
== WLAN_CIPHER_SUITE_AES_CMAC
)
435 ieee80211_aes_cmac_key_free(key
->u
.aes_cmac
.tfm
);
437 ieee80211_debugfs_key_remove(key
);
438 key
->sdata
->crypto_tx_tailroom_needed_cnt
--;
444 int ieee80211_key_link(struct ieee80211_key
*key
,
445 struct ieee80211_sub_if_data
*sdata
,
446 struct sta_info
*sta
)
448 struct ieee80211_key
*old_key
;
455 pairwise
= key
->conf
.flags
& IEEE80211_KEY_FLAG_PAIRWISE
;
456 idx
= key
->conf
.keyidx
;
457 key
->local
= sdata
->local
;
463 * some hardware cannot handle TKIP with QoS, so
464 * we indicate whether QoS could be in use.
466 if (test_sta_flags(sta
, WLAN_STA_WME
))
467 key
->conf
.flags
|= IEEE80211_KEY_FLAG_WMM_STA
;
469 if (sdata
->vif
.type
== NL80211_IFTYPE_STATION
) {
473 * We're getting a sta pointer in, so must be under
474 * appropriate locking for sta_info_get().
477 /* same here, the AP could be using QoS */
478 ap
= sta_info_get(key
->sdata
, key
->sdata
->u
.mgd
.bssid
);
480 if (test_sta_flags(ap
, WLAN_STA_WME
))
482 IEEE80211_KEY_FLAG_WMM_STA
;
487 mutex_lock(&sdata
->local
->key_mtx
);
490 old_key
= key_mtx_dereference(sdata
->local
, sta
->ptk
);
492 old_key
= key_mtx_dereference(sdata
->local
, sta
->gtk
[idx
]);
494 old_key
= key_mtx_dereference(sdata
->local
, sdata
->keys
[idx
]);
496 increment_tailroom_need_count(sdata
);
498 __ieee80211_key_replace(sdata
, sta
, pairwise
, old_key
, key
);
499 __ieee80211_key_destroy(old_key
);
501 ieee80211_debugfs_key_add(key
);
503 ret
= ieee80211_key_enable_hw_accel(key
);
505 mutex_unlock(&sdata
->local
->key_mtx
);
510 void __ieee80211_key_free(struct ieee80211_key
*key
)
516 * Replace key with nothingness if it was ever used.
519 __ieee80211_key_replace(key
->sdata
, key
->sta
,
520 key
->conf
.flags
& IEEE80211_KEY_FLAG_PAIRWISE
,
522 __ieee80211_key_destroy(key
);
525 void ieee80211_key_free(struct ieee80211_local
*local
,
526 struct ieee80211_key
*key
)
528 mutex_lock(&local
->key_mtx
);
529 __ieee80211_key_free(key
);
530 mutex_unlock(&local
->key_mtx
);
533 void ieee80211_enable_keys(struct ieee80211_sub_if_data
*sdata
)
535 struct ieee80211_key
*key
;
539 if (WARN_ON(!ieee80211_sdata_running(sdata
)))
542 mutex_lock(&sdata
->local
->key_mtx
);
544 sdata
->crypto_tx_tailroom_needed_cnt
= 0;
546 list_for_each_entry(key
, &sdata
->key_list
, list
) {
547 increment_tailroom_need_count(sdata
);
548 ieee80211_key_enable_hw_accel(key
);
551 mutex_unlock(&sdata
->local
->key_mtx
);
554 void ieee80211_disable_keys(struct ieee80211_sub_if_data
*sdata
)
556 struct ieee80211_key
*key
;
560 mutex_lock(&sdata
->local
->key_mtx
);
562 list_for_each_entry(key
, &sdata
->key_list
, list
)
563 ieee80211_key_disable_hw_accel(key
);
565 mutex_unlock(&sdata
->local
->key_mtx
);
568 void ieee80211_free_keys(struct ieee80211_sub_if_data
*sdata
)
570 struct ieee80211_key
*key
, *tmp
;
572 mutex_lock(&sdata
->local
->key_mtx
);
574 ieee80211_debugfs_key_remove_mgmt_default(sdata
);
576 list_for_each_entry_safe(key
, tmp
, &sdata
->key_list
, list
)
577 __ieee80211_key_free(key
);
579 ieee80211_debugfs_key_update_default(sdata
);
581 mutex_unlock(&sdata
->local
->key_mtx
);