mac80211_hwsim: fix use-after-free bug in hwsim_exit_net

When destroying a net namespace, all hwsim interfaces, which are not
created in default namespace are deleted. But the async deletion of the
interfaces could last longer than the actual destruction of the
namespace, which results to an use after free bug. Therefore use
synchronous deletion in this case.

Fixes: 100cb9ff40e0 ("mac80211_hwsim: Allow managing radios from non-initial namespaces")
Reported-by: syzbot+70ce058e01259de7bb1d@syzkaller.appspotmail.com
Signed-off-by: Benjamin Beichler <benjamin.beichler@uni-rostock.de>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>

diff --git a/drivers/net/wireless/mac80211_hwsim.c b/drivers/net/wireless/mac80211_hwsim.c
index 930ddef91093a3594c4a134dc5ce0597c5df1e64..d9527c7b50d47f1b004c8c7730278769782a8180 100644 (file)
--- a/drivers/net/wireless/mac80211_hwsim.c
+++ b/drivers/net/wireless/mac80211_hwsim.c
@@ -3528,8 +3528,12 @@ static void __net_exit hwsim_exit_net(struct net *net)
                list_del(&data->list);
                rhashtable_remove_fast(&hwsim_radios_rht, &data->rht,
                                       hwsim_rht_params);
-               INIT_WORK(&data->destroy_work, destroy_radio);
-               queue_work(hwsim_wq, &data->destroy_work);
+               hwsim_radios_generation++;
+               spin_unlock_bh(&hwsim_radio_lock);
+               mac80211_hwsim_del_radio(data,
+                                        wiphy_name(data->hw->wiphy),
+                                        NULL);
+               spin_lock_bh(&hwsim_radio_lock);
        }
        spin_unlock_bh(&hwsim_radio_lock);