netdev - [PATCH 1/5] vti6: fix PMTU caching and reporting on xmit

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]

Date:   Fri, 27 Jul 2018 08:51:50 +0200
From:   Steffen Klassert <steffen.klassert@...unet.com>
To:     David Miller <davem@...emloft.net>
CC:     Herbert Xu <herbert@...dor.apana.org.au>,
        Steffen Klassert <steffen.klassert@...unet.com>,
        <netdev@...r.kernel.org>
Subject: [PATCH 1/5] vti6: fix PMTU caching and reporting on xmit

From: Eyal Birger <eyal.birger@...il.com>

When setting the skb->dst before doing the MTU check, the route PMTU
caching and reporting is done on the new dst which is about to be
released.

Instead, PMTU handling should be done using the original dst.

This is aligned with IPv4 VTI.

Fixes: ccd740cbc6 ("vti6: Add pmtu handling to vti6_xmit.")
Signed-off-by: Eyal Birger <eyal.birger@...il.com>
Signed-off-by: Steffen Klassert <steffen.klassert@...unet.com>
---
 net/ipv6/ip6_vti.c | 11 ++++++-----
 1 file changed, 6 insertions(+), 5 deletions(-)

diff --git a/net/ipv6/ip6_vti.c b/net/ipv6/ip6_vti.c
index b7f28deddaea..c72ae3a4fe09 100644
--- a/net/ipv6/ip6_vti.c
+++ b/net/ipv6/ip6_vti.c
@@ -480,10 +480,6 @@ vti6_xmit(struct sk_buff *skb, struct net_device *dev, struct flowi *fl)
 		goto tx_err_dst_release;
 	}
 
-	skb_scrub_packet(skb, !net_eq(t->net, dev_net(dev)));
-	skb_dst_set(skb, dst);
-	skb->dev = skb_dst(skb)->dev;
-
 	mtu = dst_mtu(dst);
 	if (!skb->ignore_df && skb->len > mtu) {
 		skb_dst_update_pmtu(skb, mtu);
@@ -498,9 +494,14 @@ vti6_xmit(struct sk_buff *skb, struct net_device *dev, struct flowi *fl)
 				  htonl(mtu));
 		}
 
-		return -EMSGSIZE;
+		err = -EMSGSIZE;
+		goto tx_err_dst_release;
 	}
 
+	skb_scrub_packet(skb, !net_eq(t->net, dev_net(dev)));
+	skb_dst_set(skb, dst);
+	skb->dev = skb_dst(skb)->dev;
+
 	err = dst_output(t->net, skb->sk, skb);
 	if (net_xmit_eval(err) == 0) {
 		struct pcpu_sw_netstats *tstats = this_cpu_ptr(dev->tstats);
-- 
2.14.1