wifi: mac80211: check/clear fast rx for non-4addr sta VLAN changes

When moving a station out of a VLAN and deleting the VLAN afterwards, the
fast_rx entry still holds a pointer to the VLAN's netdev, which can cause
use-after-free bugs. Fix this by immediately calling ieee80211_check_fast_rx
after the VLAN change.

Cc: stable@vger.kernel.org
Reported-by: ranygh@riseup.net
Signed-off-by: Felix Fietkau <nbd@nbd.name>
Link: https://msgid.link/20240316074336.40442-1-nbd@nbd.name
Signed-off-by: Johannes Berg <johannes.berg@intel.com>

diff --git a/net/mac80211/cfg.c b/net/mac80211/cfg.c
index f03452dc716d5d9588fe5c50a09888ae78c75402..f67c1d0218121dc98b67af7201686a0c0b2ad817 100644 (file)
--- a/net/mac80211/cfg.c
+++ b/net/mac80211/cfg.c
@@ -2199,15 +2199,14 @@ static int ieee80211_change_station(struct wiphy *wiphy,
                }
 
                if (sta->sdata->vif.type == NL80211_IFTYPE_AP_VLAN &&
-                   sta->sdata->u.vlan.sta) {
-                       ieee80211_clear_fast_rx(sta);
+                   sta->sdata->u.vlan.sta)
                        RCU_INIT_POINTER(sta->sdata->u.vlan.sta, NULL);
-               }
 
                if (test_sta_flag(sta, WLAN_STA_AUTHORIZED))
                        ieee80211_vif_dec_num_mcast(sta->sdata);
 
                sta->sdata = vlansdata;
+               ieee80211_check_fast_rx(sta);
                ieee80211_check_fast_xmit(sta);
 
                if (test_sta_flag(sta, WLAN_STA_AUTHORIZED)) {