4.9-stable review patch. If anyone has any objections, please let me know.
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From: Eyal Birger eyal.birger@gmail.com
[ Upstream commit d6990976af7c5d8f55903bfb4289b6fb030bf754 ]
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@gmail.com Signed-off-by: Steffen Klassert steffen.klassert@secunet.com Signed-off-by: Sasha Levin alexander.levin@microsoft.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- net/ipv6/ip6_vti.c | 11 ++++++----- 1 file changed, 6 insertions(+), 5 deletions(-)
--- a/net/ipv6/ip6_vti.c +++ b/net/ipv6/ip6_vti.c @@ -480,10 +480,6 @@ vti6_xmit(struct sk_buff *skb, struct ne 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(skb)->ops->update_pmtu(dst, NULL, skb, mtu); @@ -498,9 +494,14 @@ vti6_xmit(struct sk_buff *skb, struct ne 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);