Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756066AbdLOK2Z (ORCPT ); Fri, 15 Dec 2017 05:28:25 -0500 Received: from mail.linuxfoundation.org ([140.211.169.12]:34678 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932098AbdLOJtE (ORCPT ); Fri, 15 Dec 2017 04:49:04 -0500 From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Steffen Klassert , Sasha Levin Subject: [PATCH 4.4 040/105] vti6: Dont report path MTU below IPV6_MIN_MTU. Date: Fri, 15 Dec 2017 10:44:38 +0100 Message-Id: <20171215092308.003940366@linuxfoundation.org> X-Mailer: git-send-email 2.15.1 In-Reply-To: <20171215092305.994559179@linuxfoundation.org> References: <20171215092305.994559179@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 Content-Length: 1260 Lines: 43 4.4-stable review patch. If anyone has any objections, please let me know. ------------------ From: Steffen Klassert [ Upstream commit e3dc847a5f85b43ee2bfc8eae407a7e383483228 ] In vti6_xmit(), the check for IPV6_MIN_MTU before we send a ICMPV6_PKT_TOOBIG message is missing. So we might report a PMTU below 1280. Fix this by adding the required check. Fixes: ccd740cbc6e ("vti6: Add pmtu handling to vti6_xmit.") Signed-off-by: Steffen Klassert Signed-off-by: Sasha Levin Signed-off-by: Greg Kroah-Hartman --- net/ipv6/ip6_vti.c | 8 ++++++-- 1 file changed, 6 insertions(+), 2 deletions(-) --- a/net/ipv6/ip6_vti.c +++ b/net/ipv6/ip6_vti.c @@ -474,11 +474,15 @@ vti6_xmit(struct sk_buff *skb, struct ne if (!skb->ignore_df && skb->len > mtu) { skb_dst(skb)->ops->update_pmtu(dst, NULL, skb, mtu); - if (skb->protocol == htons(ETH_P_IPV6)) + if (skb->protocol == htons(ETH_P_IPV6)) { + if (mtu < IPV6_MIN_MTU) + mtu = IPV6_MIN_MTU; + icmpv6_send(skb, ICMPV6_PKT_TOOBIG, 0, mtu); - else + } else { icmp_send(skb, ICMP_DEST_UNREACH, ICMP_FRAG_NEEDED, htonl(mtu)); + } return -EMSGSIZE; }