From: Sabrina Dubroca <sd@queasysnail.net>
Date: Tue, 4 Aug 2020 09:37:29 +0000 (+0200)
Subject: xfrmi: drop ignore_df check before updating pmtu
X-Git-Tag: v5.8.15~90
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=1427c13cc16fd402fb42753c5e39d64a9c085dd4;p=thirdparty%2Fkernel%2Fstable.git

xfrmi: drop ignore_df check before updating pmtu

commit 45a36a18d01907710bad5258d81f76c18882ad88 upstream.

xfrm interfaces currently test for !skb->ignore_df when deciding
whether to update the pmtu on the skb's dst. Because of this, no pmtu
exception is created when we do something like:

    ping -s 1438 <dest>

By dropping this check, the pmtu exception will be created and the
next ping attempt will work.

Fixes: f203b76d7809 ("xfrm: Add virtual xfrm interfaces")
Reported-by: Xiumei Mu <xmu@redhat.com>
Signed-off-by: Sabrina Dubroca <sd@queasysnail.net>
Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---

diff --git a/net/xfrm/xfrm_interface.c b/net/xfrm/xfrm_interface.c
index b615729812e5a..ade2eba863b39 100644
--- a/net/xfrm/xfrm_interface.c
+++ b/net/xfrm/xfrm_interface.c
@@ -292,7 +292,7 @@ xfrmi_xmit2(struct sk_buff *skb, struct net_device *dev, struct flowi *fl)
 	}
 
 	mtu = dst_mtu(dst);
-	if (!skb->ignore_df && skb->len > mtu) {
+	if (skb->len > mtu) {
 		skb_dst_update_pmtu_no_confirm(skb, mtu);
 
 		if (skb->protocol == htons(ETH_P_IPV6)) {