From: Eric Dumazet <edumazet@google.com>
Date: Wed, 27 Jan 2016 00:59:42 +0000 (-0800)
Subject: ipv4: early demux should be aware of fragments
X-Git-Tag: v4.5-rc3~21^2~19
X-Git-Url: https://www.infradead.org/git/?a=commitdiff_plain;h=63e51b6a24f1bee5363056b7aee3a468b12c546b;p=linux.git

ipv4: early demux should be aware of fragments

We should not assume a valid protocol header is present,
as this is not the case for IPv4 fragments.

Lets avoid extra cache line misses and potential bugs
if we actually find a socket and incorrectly uses its dst.

Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
---

diff --git a/net/ipv4/ip_input.c b/net/ipv4/ip_input.c
index b1209b63381f..d77eb0c3b684 100644
--- a/net/ipv4/ip_input.c
+++ b/net/ipv4/ip_input.c
@@ -316,7 +316,10 @@ static int ip_rcv_finish(struct net *net, struct sock *sk, struct sk_buff *skb)
 	const struct iphdr *iph = ip_hdr(skb);
 	struct rtable *rt;
 
-	if (sysctl_ip_early_demux && !skb_dst(skb) && !skb->sk) {
+	if (sysctl_ip_early_demux &&
+	    !skb_dst(skb) &&
+	    !skb->sk &&
+	    !ip_is_fragment(iph)) {
 		const struct net_protocol *ipprot;
 		int protocol = iph->protocol;