mac80211: drop robust management frames from unknown TA

commit 588f7d39b3592a36fb7702ae3b8bdd9be4621e2f upstream.

When receiving a robust management frame, drop it if we don't have
rx->sta since then we don't have a security association and thus
couldn't possibly validate the frame.

Cc: stable@vger.kernel.org
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/net/mac80211/rx.c b/net/mac80211/rx.c
index 23f6c8b..3b423c5 100644
--- a/net/mac80211/rx.c
+++ b/net/mac80211/rx.c
@@ -3568,6 +3568,8 @@
 	case NL80211_IFTYPE_STATION:
 		if (!bssid && !sdata->u.mgd.use_4addr)
 			return false;
+		if (ieee80211_is_robust_mgmt_frame(skb) && !rx->sta)
+			return false;
 		if (multicast)
 			return true;
 		return ether_addr_equal(sdata->vif.addr, hdr->addr1);