mac80211: flush keys for AP mode on ieee80211_do_stop

Userspace can add keys to an AP mode interface before start_ap has been
called. If there have been no calls to start_ap/stop_ap in the mean
time, the keys will still be around when the interface is brought down.

Signed-off-by: Felix Fietkau <nbd@openwrt.org>
[adjust comments, fix AP_VLAN case]
Signed-off-by: Johannes Berg <johannes.berg@intel.com>

1 files changed, 6 insertions, 5 deletions

diff --git a/net/mac80211/iface.c b/net/mac80211/iface.c
index af237223a8cd..3b9e2b7b3f30 100644
--- a/net/mac80211/iface.c
+++ b/net/mac80211/iface.c
@@ -898,6 +898,8 @@ static void ieee80211_do_stop(struct ieee80211_sub_if_data *sdata,
                 list_del(&sdata->u.vlan.list);
                 mutex_unlock(&local->mtx);
                 RCU_INIT_POINTER(sdata->vif.chanctx_conf, NULL);
+                /* see comment in the default case below */
+                ieee80211_free_keys(sdata, true);
                 /* no need to tell driver */
                 break;
         case NL80211_IFTYPE_MONITOR:
@@ -923,17 +925,16 @@ static void ieee80211_do_stop(struct ieee80211_sub_if_data *sdata,
                 /*
                  * When we get here, the interface is marked down.
                  * Free the remaining keys, if there are any
-                 * (shouldn't be, except maybe in WDS mode?)
+                 * (which can happen in AP mode if userspace sets
+                 * keys before the interface is operating, and maybe
+                 * also in WDS mode)
                  *
                  * Force the key freeing to always synchronize_net()
                  * to wait for the RX path in case it is using this
-                 * interface enqueuing frames * at this very time on
+                 * interface enqueuing frames at this very time on
                  * another CPU.
                  */
                 ieee80211_free_keys(sdata, true);
-
-                /* fall through */
-        case NL80211_IFTYPE_AP:
                 skb_queue_purge(&sdata->skb_queue);
         }