wifi: mac80211: potential NULL dereference in ieee80211_tx_control_port()

The ieee80211_lookup_ra_sta() function will sometimes set "sta" to NULL
so add this NULL check to prevent an Oops.

Fixes: 9dd1953846c7 ("wifi: nl80211/mac80211: clarify link ID in control port TX")
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Link: https://lore.kernel.org/r/YuKcTAyO94YOy0Bu@kili
Signed-off-by: Johannes Berg <johannes.berg@intel.com>

diff --git a/net/mac80211/tx.c b/net/mac80211/tx.c
index 594bd70ee641a86106034712367d44bb5253745b..bf7fe6cd9dfcad0b7d90cf35cd0bf85ed07ab554 100644 (file)
--- a/net/mac80211/tx.c
+++ b/net/mac80211/tx.c
@@ -5900,7 +5900,7 @@ int ieee80211_tx_control_port(struct wiphy *wiphy, struct net_device *dev,
                 * for MLO STA, the SA should be the AP MLD address, but
                 * the link ID has been selected already
                 */
-               if (sta->sta.mlo)
+               if (sta && sta->sta.mlo)
                        memcpy(ehdr->h_source, sdata->vif.addr, ETH_ALEN);
        }
        rcu_read_unlock();