ip6_tunnel: fix possible use-after-free on xmit (01f5bffa) · Commits · 戴 / test

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: ("ip6_tunnel, ip6_gre: fix setting of DSCP on encapsulated packets") Signed-off-by:

Haishuang Yan <yanhaishuang@cmss.chinamobile.com> Signed-off-by:

David S. Miller <davem@davemloft.net>

net/ipv6/ip6_tunnel.c

+2 −4

Original line number	Diff line number	Diff line
		@@ -1278,12 +1278,11 @@ ip4ip6_tnl_xmit(struct sk_buff skb, struct net_device dev)
		}

		fl6.flowi6_uid = sock_net_uid(dev_net(dev), NULL);
		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,
		@@ -1367,12 +1366,11 @@ ip6ip6_tnl_xmit(struct sk_buff skb, struct net_device dev)
		}

		fl6.flowi6_uid = sock_net_uid(dev_net(dev), NULL);
		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,

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