From: Haishuang Yan <yanhaishuang@xxxxxxxxxxxxxxxxxxxx> [ Upstream commit 01f5bffad555f8e22a61f4b1261fe09cf1b96994 ] ip4ip6/ip6ip6 tunnels run iptunnel_handle_offloads on xmit which can cause a possible use-after-free accessing iph/ipv6h pointer since the packet will be 'uncloned' running pskb_expand_head if it is a cloned gso skb. Fixes: 0e9a709560db ("ip6_tunnel, ip6_gre: fix setting of DSCP on encapsulated packets") Signed-off-by: Haishuang Yan <yanhaishuang@xxxxxxxxxxxxxxxxxxxx> Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- net/ipv6/ip6_tunnel.c | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-) --- a/net/ipv6/ip6_tunnel.c +++ b/net/ipv6/ip6_tunnel.c @@ -1275,11 +1275,11 @@ ip4ip6_tnl_xmit(struct sk_buff *skb, str fl6.flowi6_mark = skb->mark; } + dsfield = INET_ECN_encapsulate(dsfield, ipv4_get_dsfield(iph)); + if (iptunnel_handle_offloads(skb, SKB_GSO_IPXIP6)) return -1; - dsfield = INET_ECN_encapsulate(dsfield, ipv4_get_dsfield(iph)); - skb_set_inner_ipproto(skb, IPPROTO_IPIP); err = ip6_tnl_xmit(skb, dev, dsfield, &fl6, encap_limit, &mtu, @@ -1362,11 +1362,11 @@ ip6ip6_tnl_xmit(struct sk_buff *skb, str fl6.flowi6_mark = skb->mark; } + dsfield = INET_ECN_encapsulate(dsfield, ipv6_get_dsfield(ipv6h)); + if (iptunnel_handle_offloads(skb, SKB_GSO_IPXIP6)) return -1; - dsfield = INET_ECN_encapsulate(dsfield, ipv6_get_dsfield(ipv6h)); - skb_set_inner_ipproto(skb, IPPROTO_IPV6); err = ip6_tnl_xmit(skb, dev, dsfield, &fl6, encap_limit, &mtu,