[ Upstream commit 57031eb794906eea4e1c7b31dc1e2429c0af0c66 ]
Link layer protocols may unconditionally pull headers, as Ethernet
does in eth_type_trans. Ensure that the entire link layer header
always lies in the skb linear segment. tpacket_snd has such a check.
Extend this to packet_snd.
Variable length link layer headers complicate the computation
somewhat. Here skb->len may be smaller than dev->hard_header_len.
Round up the linear length to be at least as long as the smallest of
Reported-by: Dmitry Vyukov <email@example.com>
Signed-off-by: Willem de Bruijn <firstname.lastname@example.org>
Acked-by: Eric Dumazet <email@example.com>
Signed-off-by: David S. Miller <firstname.lastname@example.org>
Signed-off-by: Greg Kroah-Hartman <email@example.com>