[051/272] mac80211: add missing synchronize_rcu

Greg KH
2011-02-16T00:19:28Z

From: Johannes Berg <johannes.berg@intel.com>

commit d2460f4b2fa6dbdeec800414f9cf5b1fc8b71197 upstream.

commit ad0e2b5a00dbec303e4682b403bb6703d11dcdb2
Author: Johannes Berg <johannes.berg@intel.com>
Date: Tue Jun 1 10:19:19 2010 +0200

mac80211: simplify key locking

removed the synchronization against RCU and thus
opened a race window where we can use a key for
TX while it is already freed. Put a synchronisation
into the right place to close that window.

Reported-by: Jussi Kivilinna <jussi.kivilinna@mbnet.fi>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

---
net/mac80211/key.c | 6 ++++++
1 file changed, 6 insertions(+)

--- a/net/mac80211/key.c
+++ b/net/mac80211/key.c
@@ -366,6 +366,12 @@ static void __ieee80211_key_destroy(stru
if (!key)
return;

+ /*
+ * Synchronize so the TX path can no longer be using
+ * this key before we free/remove it.
+ */
+ synchronize_rcu();
+
if (key->local)
ieee80211_key_disable_hw_accel(key);