mac80211: Run TXQ teardown code before de-registering interfaces

The TXQ teardown code can reference the vif data structures that are
stored in the netdev private memory area if there are still packets on
the queue when it is being freed. Since the TXQ teardown code is run
after the netdevs are freed, this can lead to a use-after-free. Fix this
by moving the TXQ teardown code to earlier in ieee80211_unregister_hw().

Reported-by: Ben Greear <greearb@candelatech.com>
Tested-by: Ben Greear <greearb@candelatech.com>
Signed-off-by: Toke Høiland-Jørgensen <toke@toke.dk>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>

diff --git a/net/mac80211/main.c b/net/mac80211/main.c
index fb73451ed85ec65cd0b4b5cc3808d51d40a8dd39..0358f20b675f26756332cc91d6fbcb55fad0c9ba 100644 (file)
--- a/net/mac80211/main.c
+++ b/net/mac80211/main.c
@@ -1182,6 +1182,7 @@ void ieee80211_unregister_hw(struct ieee80211_hw *hw)
 #if IS_ENABLED(CONFIG_IPV6)
        unregister_inet6addr_notifier(&local->ifa6_notifier);
 #endif
+       ieee80211_txq_teardown_flows(local);
 
        rtnl_lock();
 
@@ -1210,7 +1211,6 @@ void ieee80211_unregister_hw(struct ieee80211_hw *hw)
        skb_queue_purge(&local->skb_queue);
        skb_queue_purge(&local->skb_queue_unreliable);
        skb_queue_purge(&local->skb_queue_tdls_chsw);
-       ieee80211_txq_teardown_flows(local);
 
        destroy_workqueue(local->workqueue);
        wiphy_unregister(local->hw.wiphy);