From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753531AbdHIUmw (ORCPT ); Wed, 9 Aug 2017 16:42:52 -0400 Received: from mail.linuxfoundation.org ([140.211.169.12]:48068 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751904AbdHIUmu (ORCPT ); Wed, 9 Aug 2017 16:42:50 -0400 From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Zheng Li , "David S. Miller" , Sasha Levin Subject: [PATCH 3.18 92/92] ipv4: Should use consistent conditional judgement for ip fragment in __ip_append_data and ip_finish_output Date: Wed, 9 Aug 2017 13:38:00 -0700 Message-Id: <20170809202159.214209879@linuxfoundation.org> X-Mailer: git-send-email 2.14.0 In-Reply-To: <20170809202155.435709888@linuxfoundation.org> References: <20170809202155.435709888@linuxfoundation.org> User-Agent: quilt/0.65 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 3.18-stable review patch. If anyone has any objections, please let me know. ------------------ From: zheng li [ 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 Signed-off-by: David S. Miller Signed-off-by: Sasha Levin Signed-off-by: Greg Kroah-Hartman --- 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 @@ -888,7 +888,7 @@ 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)) {