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>

1 files changed, 6 insertions, 2 deletions

diff --git a/drivers/net/wireless/mac80211_hwsim.c b/drivers/net/wireless/mac80211_hwsim.c
index 930ddef91093..d9527c7b50d4 100644
--- 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);