patch 9b8a74e3 in mainline.

Michael Wu noticed that the skb length checking is not taken care of enough when
a packet is presented on the Monitor interface for injection.

This patch improves the sanity checking and removes fake offsets placed
into the skb network and transport header.
Signed-off-by: Andy Green <andy@warmcat.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>