mac80211: do not transmit frames on unconfigured 4-addr vlan interfaces

commit 3f0e0b220f80075ce15483b20458192c0ac27426 upstream.

If frames are transmitted on 4-addr ap vlan interfaces with no station,
they end up being transmitted unencrypted, even if the ap interface
uses WPA. This patch add some sanity checking to make sure that this
does not happen.

Signed-off-by: Felix Fietkau <nbd@openwrt.org>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

1 files changed, 4 insertions, 1 deletions

diff --git a/net/mac80211/tx.c b/net/mac80211/tx.c
index ac210b586702..70c79c3013fa 100644
--- a/net/mac80211/tx.c
+++ b/net/mac80211/tx.c
@@ -1052,8 +1052,11 @@ ieee80211_tx_prepare(struct ieee80211_sub_if_data *sdata,
 
         hdr = (struct ieee80211_hdr *) skb->data;
 
-        if (sdata->vif.type == NL80211_IFTYPE_AP_VLAN)
+        if (sdata->vif.type == NL80211_IFTYPE_AP_VLAN) {
                 tx->sta = rcu_dereference(sdata->u.vlan.sta);
+                if (!tx->sta && sdata->dev->ieee80211_ptr->use_4addr)
+                        return TX_DROP;
+        }
         if (!tx->sta)
                 tx->sta = sta_info_get(local, hdr->addr1);