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

   1 From foo@baz Wed Aug  9 12:42:27 PDT 2017
   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
   9 [ Upstream commit 0a28cfd51e17f4f0a056bcf66bfbe492c3b99f38 ]
  10
  11 There is an inconsistent conditional judgement in __ip_append_data and
  12 ip_finish_output functions, the variable length in __ip_append_data just
  13 include the length of application's payload and udp header, don't include
  14 the length of ip header, but in ip_finish_output use
  15 (skb->len > ip_skb_dst_mtu(skb)) as judgement, and skb->len include the
  16 length of ip header.
  17
  18 That causes some particular application's udp payload whose length is
  19 between (MTU - IP Header) and MTU were fragmented by ip_fragment even
  20 though the rst->dev support UFO feature.
  21
  22 Add the length of ip header to length in __ip_append_data to keep
  23 consistent conditional judgement as ip_finish_output for ip fragment.
  24
  25 Signed-off-by: Zheng Li <james.z.li@ericsson.com>
  26 Signed-off-by: David S. Miller <davem@davemloft.net>
  27 Signed-off-by: Sasha Levin <alexander.levin@verizon.com>
  28 Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
  29 ---
  30  net/ipv4/ip_output.c |    2 +-
  31  1 file changed, 1 insertion(+), 1 deletion(-)
  32
  33 --- a/net/ipv4/ip_output.c
  34 +++ b/net/ipv4/ip_output.c
  35 @@ -888,7 +888,7 @@ static int __ip_append_data(struct sock
  36                 csummode = CHECKSUM_PARTIAL;
  37
  38         cork->length += length;
  39 -       if (((length > mtu) || (skb && skb_is_gso(skb))) &&
  40 +       if ((((length + fragheaderlen) > mtu) || (skb && skb_is_gso(skb))) &&
  41             (sk->sk_protocol == IPPROTO_UDP) &&
  42             (rt->dst.dev->features & NETIF_F_UFO) && !rt->dst.header_len &&
  43             (sk->sk_type == SOCK_DGRAM)) {