linux-kernel - [PATCH 4.4 06/60] vti6: remove !skb->ignore_df check from vti6

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-Id: <20180913131745.580366897@linuxfoundation.org>
Date:   Thu, 13 Sep 2018 15:30:13 +0200
From:   Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To:     linux-kernel@...r.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        stable@...r.kernel.org, Alexey Kodanev <alexey.kodanev@...cle.com>,
        Steffen Klassert <steffen.klassert@...unet.com>,
        "David S. Miller" <davem@...emloft.net>
Subject: [PATCH 4.4 06/60] vti6: remove !skb->ignore_df check from vti6_xmit()

4.4-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Alexey Kodanev <alexey.kodanev@...cle.com>

[ Upstream commit 9f2895461439fda2801a7906fb4c5fb3dbb37a0a ]

Before the commit d6990976af7c ("vti6: fix PMTU caching and reporting
on xmit") '!skb->ignore_df' check was always true because the function
skb_scrub_packet() was called before it, resetting ignore_df to zero.

In the commit, skb_scrub_packet() was moved below, and now this check
can be false for the packet, e.g. when sending it in the two fragments,
this prevents successful PMTU updates in such case. The next attempts
to send the packet lead to the same tx error. Moreover, vti6 initial
MTU value relies on PMTU adjustments.

This issue can be reproduced with the following LTP test script:
    udp_ipsec_vti.sh -6 -p ah -m tunnel -s 2000

Fixes: ccd740cbc6e0 ("vti6: Add pmtu handling to vti6_xmit.")
Signed-off-by: Alexey Kodanev <alexey.kodanev@...cle.com>
Acked-by: Steffen Klassert <steffen.klassert@...unet.com>
Signed-off-by: David S. Miller <davem@...emloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
---
 net/ipv6/ip6_vti.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

--- a/net/ipv6/ip6_vti.c
+++ b/net/ipv6/ip6_vti.c
@@ -470,7 +470,7 @@ vti6_xmit(struct sk_buff *skb, struct ne
 	}
 
 	mtu = dst_mtu(dst);
-	if (!skb->ignore_df && skb->len > mtu) {
+	if (skb->len > mtu) {
 		skb_dst(skb)->ops->update_pmtu(dst, NULL, skb, mtu);
 
 		if (skb->protocol == htons(ETH_P_IPV6)) {