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authorMichal Kazior <michal.kazior@tieto.com>2015-05-22 10:22:40 +0200
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2015-08-03 09:29:46 -0700
commit5c817fb317292d051103e738e825d8d543a51304 (patch)
tree4f663e59e4884482849f4e9f101812632570d8d3
parentbf95f46c3f1c3aa7f0cc026241877478487c3670 (diff)
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mac80211: prevent possible crypto tx tailroom corruption
commit ab499db80fcf07c18e4053f91a619500f663e90e upstream. There was a possible race between ieee80211_reconfig() and ieee80211_delayed_tailroom_dec(). This could result in inability to transmit data if driver crashed during roaming or rekeying and subsequent skbs with insufficient tailroom appeared. This race was probably never seen in the wild because a device driver would have to crash AND recover within 0.5s which is very unlikely. I was able to prove this race exists after changing the delay to 10s locally and crashing ath10k via debugfs immediately after GTK rekeying. In case of ath10k the counter went below 0. This was harmless but other drivers which actually require tailroom (e.g. for WEP ICV or MMIC) could end up with the counter at 0 instead of >0 and introduce insufficient skb tailroom failures because mac80211 would not resize skbs appropriately anymore. Fixes: 8d1f7ecd2af5 ("mac80211: defer tailroom counter manipulation when roaming") Signed-off-by: Michal Kazior <michal.kazior@tieto.com> Signed-off-by: Johannes Berg <johannes.berg@intel.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
-rw-r--r--net/mac80211/main.c3
1 files changed, 3 insertions, 0 deletions
diff --git a/net/mac80211/main.c b/net/mac80211/main.c
index 6658c5809353..dd6ca36c34c1 100644
--- a/net/mac80211/main.c
+++ b/net/mac80211/main.c
@@ -257,6 +257,7 @@ static void ieee80211_restart_work(struct work_struct *work)
{
struct ieee80211_local *local =
container_of(work, struct ieee80211_local, restart_work);
+ struct ieee80211_sub_if_data *sdata;
/* wait for scan work complete */
flush_workqueue(local->workqueue);
@@ -269,6 +270,8 @@ static void ieee80211_restart_work(struct work_struct *work)
mutex_unlock(&local->mtx);
rtnl_lock();
+ list_for_each_entry(sdata, &local->interfaces, list)
+ flush_delayed_work(&sdata->dec_tailroom_needed_wk);
ieee80211_scan_cancel(local);
ieee80211_reconfig(local);
rtnl_unlock();