ieee802154: lowpan_header_create check must check daddr

BugLink: https://bugs.launchpad.net/bugs/1811647

[ Upstream commit 40c3ff6d ]

Packet sockets may call dev_header_parse with NULL daddr. Make
lowpan_header_ops.create fail.

Fixes: 87a93e4e ("ieee802154: change needed headroom/tailroom")
Signed-off-by: Willem de Bruijn <willemb@google.com>
Acked-by: Alexander Aring <aring@mojatatu.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Juerg Haefliger <juergh@canonical.com>
Signed-off-by: Stefan Bader <stefan.bader@canonical.com>

net/ieee802154/6lowpan/tx.c

@@ -55,6 +55,9 @@ int lowpan_header_create(struct sk_buff *skb, struct net_device *ldev,
 	const u8 *daddr = _daddr;
 	struct lowpan_addr_info *info;
 
+	if (!daddr)
+		return -EINVAL;
+
 	/* TODO:
 	 * if this package isn't ipv6 one, where should it be routed?
 	 */