| From | Greg Kroah-Hartman <> | Subject | [PATCH 4.9 92/93] ipv4: Should use consistent conditional judgement for ip fragment in __ip_append_data and ip_finish_output | Date | Wed, 9 Aug 2017 11:14:25 -0700 |
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4.9-stable review patch. If anyone has any objections, please let me know.
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From: zheng li <james.z.li@ericsson.com>
[ Upstream commit 0a28cfd51e17f4f0a056bcf66bfbe492c3b99f38 ]
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: Sasha Levin <alexander.levin@verizon.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> --- 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 @@ -936,7 +936,7 @@ static int __ip_append_data(struct sock csummode = CHECKSUM_PARTIAL; cork->length += length; - if (((length > mtu) || (skb && skb_is_gso(skb))) && + if ((((length + fragheaderlen) > mtu) || (skb && skb_is_gso(skb))) && (sk->sk_protocol == IPPROTO_UDP) && (rt->dst.dev->features & NETIF_F_UFO) && !rt->dst.header_len && (sk->sk_type == SOCK_DGRAM) && !sk->sk_no_check_tx) {
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