git.ipfire.org Git - thirdparty/kernel/stable-queue.git/blob

   1 From 0a28cfd51e17f4f0a056bcf66bfbe492c3b99f38 Mon Sep 17 00:00:00 2001
   2 From: zheng li <james.z.li@ericsson.com>
   3 Date: Mon, 12 Dec 2016 09:56:05 +0800
   4 Subject: ipv4: Should use consistent conditional judgement for ip fragment in __ip_append_data and ip_finish_output
   5
   6 From: zheng li <james.z.li@ericsson.com>
   7
   8 commit 0a28cfd51e17f4f0a056bcf66bfbe492c3b99f38 upstream.
   9
  10 There is an inconsistent conditional judgement in __ip_append_data and
  11 ip_finish_output functions, the variable length in __ip_append_data just
  12 include the length of application's payload and udp header, don't include
  13 the length of ip header, but in ip_finish_output use
  14 (skb->len > ip_skb_dst_mtu(skb)) as judgement, and skb->len include the
  15 length of ip header.
  16
  17 That causes some particular application's udp payload whose length is
  18 between (MTU - IP Header) and MTU were fragmented by ip_fragment even
  19 though the rst->dev support UFO feature.
  20
  21 Add the length of ip header to length in __ip_append_data to keep
  22 consistent conditional judgement as ip_finish_output for ip fragment.
  23
  24 Signed-off-by: Zheng Li <james.z.li@ericsson.com>
  25 Signed-off-by: David S. Miller <davem@davemloft.net>
  26 Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
  27
  28 ---
  29  net/ipv4/ip_output.c |    2 +-
  30  1 file changed, 1 insertion(+), 1 deletion(-)
  31
  32 --- a/net/ipv4/ip_output.c
  33 +++ b/net/ipv4/ip_output.c
  34 @@ -923,7 +923,7 @@ static int __ip_append_data(struct sock
  35
  36         cork->length += length;
  37         if ((skb && skb_is_gso(skb)) ||
  38 -           ((length > mtu) &&
  39 +           (((length + fragheaderlen) > mtu) &&
  40             (skb_queue_len(queue) <= 1) &&
  41             (sk->sk_protocol == IPPROTO_UDP) &&
  42             (rt->dst.dev->features & NETIF_F_UFO) && !rt->dst.header_len &&