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Commit b26b5e08 authored by Johannes Berg's avatar Johannes Berg Committed by Greg Kroah-Hartman
Browse files

mac80211: pause TX while changing interface type 



[ Upstream commit 054c9939b4800a91475d8d89905827bf9e1ad97a ]

syzbot reported a crash that happened when changing the interface
type around a lot, and while it might have been easy to fix just
the symptom there, a little deeper investigation found that really
the reason is that we allowed packets to be transmitted while in
the middle of changing the interface type.

Disallow TX by stopping the queues while changing the type.

Fixes: 34d4bc4d ("mac80211: support runtime interface type changes")
Reported-by: default avatar <syzbot+d7a3b15976bf7de2238a@syzkaller.appspotmail.com>
Link: https://lore.kernel.org/r/20210122171115.b321f98f4d4f.I6997841933c17b093535c31d29355be3c0c39628@changeid


Signed-off-by: default avatarJohannes Berg <johannes.berg@intel.com>
Signed-off-by: default avatarSasha Levin <sashal@kernel.org>
parent 2f48393f

net/mac80211/ieee80211_i.h

+1 −0
Original line number Diff line number Diff line
@@ -1051,6 +1051,7 @@ enum queue_stop_reason { 
	IEEE80211_QUEUE_STOP_REASON_FLUSH,

	IEEE80211_QUEUE_STOP_REASON_TDLS_TEARDOWN,

	IEEE80211_QUEUE_STOP_REASON_RESERVE_TID,

	IEEE80211_QUEUE_STOP_REASON_IFTYPE_CHANGE,



	IEEE80211_QUEUE_STOP_REASONS,

};

net/mac80211/iface.c

+6 −0
Original line number Diff line number Diff line
@@ -1542,6 +1542,10 @@ static int ieee80211_runtime_change_iftype(struct ieee80211_sub_if_data *sdata, 
	if (ret)

		return ret;



	ieee80211_stop_vif_queues(local, sdata,

				  IEEE80211_QUEUE_STOP_REASON_IFTYPE_CHANGE);

	synchronize_net();



	ieee80211_do_stop(sdata, false);



	ieee80211_teardown_sdata(sdata);
@@ -1562,6 +1566,8 @@ static int ieee80211_runtime_change_iftype(struct ieee80211_sub_if_data *sdata, 
	err = ieee80211_do_open(&sdata->wdev, false);

	WARN(err, "type change: do_open returned %d", err);



	ieee80211_wake_vif_queues(local, sdata,

				  IEEE80211_QUEUE_STOP_REASON_IFTYPE_CHANGE);

	return ret;

}