From 6b58ee6bb2fc8f507602656ea7072e546101337b Mon Sep 17 00:00:00 2001 From: zheng li <james.z.li@ericsson.com> Date: Mon, 12 Dec 2016 09:56:05 +0800 Subject: [PATCH] ipv4: Should use consistent conditional judgement for ip fragment in __ip_append_data and ip_finish_output commit 0a28cfd51e17f4f0a056bcf66bfbe492c3b99f38 upstream. There is an inconsistent conditional judgement in __ip_append_data and ip_finish_output functions, the variable length in __ip_append_data just include the length of application's payload and udp header, don't include the length of ip header, but in ip_finish_output use (skb->len > ip_skb_dst_mtu(skb)) as judgement, and skb->len include the length of ip header. That causes some particular application's udp payload whose length is between (MTU - IP Header) and MTU were fragmented by ip_fragment even though the rst->dev support UFO feature. Add the length of ip header to length in __ip_append_data to keep consistent conditional judgement as ip_finish_output for ip fragment. Signed-off-by: Zheng Li <james.z.li@ericsson.com> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> --- net/ipv4/ip_output.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/net/ipv4/ip_output.c b/net/ipv4/ip_output.c index 9287533206327..5ed8740017d0d 100644 --- a/net/ipv4/ip_output.c +++ b/net/ipv4/ip_output.c @@ -889,7 +889,7 @@ static int __ip_append_data(struct sock *sk, cork->length += length; if ((skb && skb_is_gso(skb)) || - ((length > mtu) && + (((length + fragheaderlen) > mtu) && (skb_queue_len(queue) <= 1) && (sk->sk_protocol == IPPROTO_UDP) && (rt->dst.dev->features & NETIF_F_UFO) && !rt->dst.header_len &&