This is a note to let you know that I've just added the patch titled
ipv4: Should use consistent conditional judgement for ip fragment in __ip_append_data and ip_finish_output
to the 4.4-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
ipv4-should-use-consistent-conditional-judgement-for-ip-fragment-in-__ip_append_data-and-ip_finish_output.patch
and it can be found in the queue-4.4 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From 0a28cfd51e17f4f0a056bcf66bfbe492c3b99f38 Mon Sep 17 00:00:00 2001
From: zheng li <james.z.li@xxxxxxxxxxxx>
Date: Mon, 12 Dec 2016 09:56:05 +0800
Subject: ipv4: Should use consistent conditional judgement for ip fragment in __ip_append_data and ip_finish_output
From: zheng li <james.z.li@xxxxxxxxxxxx>
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@xxxxxxxxxxxx>
Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
net/ipv4/ip_output.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
--- a/net/ipv4/ip_output.c
+++ b/net/ipv4/ip_output.c
@@ -923,7 +923,7 @@ static int __ip_append_data(struct sock
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 &&
Patches currently in stable-queue which might be from james.z.li@xxxxxxxxxxxx are
queue-4.4/ipv4-should-use-consistent-conditional-judgement-for-ip-fragment-in-__ip_append_data-and-ip_finish_output.patch
queue-4.4/revert-ipv4-should-use-consistent-conditional-judgement-for-ip-fragment-in-__ip_append_data-and-ip_finish_output.patch