From 51846355bc239b7d229ed7a1ea7b0333cbd23f01 Mon Sep 17 00:00:00 2001 From: Atzm Watanabe Date: Tue, 17 Dec 2013 22:53:32 +0900 Subject: [PATCH] packet: make aligned size of struct tpacket{2,3}_hdr clear struct tpacket{2,3}_hdr is aligned to a multiple of TPACKET_ALIGNMENT. We may add members to them until current aligned size without forcing userspace to call getsockopt(..., PACKET_HDRLEN, ...). Signed-off-by: Atzm Watanabe Acked-by: Daniel Borkmann Signed-off-by: David S. Miller --- net/packet/af_packet.c | 7 +++++++ 1 file changed, 7 insertions(+) diff --git a/net/packet/af_packet.c b/net/packet/af_packet.c index 24675f0..4fd5218 100644 --- a/net/packet/af_packet.c +++ b/net/packet/af_packet.c @@ -1812,6 +1812,13 @@ static int tpacket_rcv(struct sk_buff *skb, struct net_device *dev, struct timespec ts; __u32 ts_status; + /* struct tpacket{2,3}_hdr is aligned to a multiple of TPACKET_ALIGNMENT. + * We may add members to them until current aligned size without forcing + * userspace to call getsockopt(..., PACKET_HDRLEN, ...). + */ + BUILD_BUG_ON(TPACKET_ALIGN(sizeof(*h.h2)) != 32); + BUILD_BUG_ON(TPACKET_ALIGN(sizeof(*h.h3)) != 48); + if (skb->pkt_type == PACKET_LOOPBACK) goto drop; -- 2.7.4