From: Paolo Abeni Date: Mon, 24 Sep 2018 13:48:19 +0000 (+0200) Subject: ip_tunnel: be careful when accessing the inner header X-Git-Tag: v4.14.77~105 X-Git-Url: https://www.infradead.org/git/?a=commitdiff_plain;h=deb33b68f40e788c974acf61bc220dc077cb8032;p=users%2Fjedix%2Flinux-maple.git ip_tunnel: be careful when accessing the inner header [ Upstream commit ccfec9e5cb2d48df5a955b7bf47f7782157d3bc2] Cong noted that we need the same checks introduced by commit 76c0ddd8c3a6 ("ip6_tunnel: be careful when accessing the inner header") even for ipv4 tunnels. Fixes: c54419321455 ("GRE: Refactor GRE tunneling code.") Suggested-by: Cong Wang Signed-off-by: Paolo Abeni Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman --- diff --git a/net/ipv4/ip_tunnel.c b/net/ipv4/ip_tunnel.c index 4784f3f36b7e..72eee34092ae 100644 --- a/net/ipv4/ip_tunnel.c +++ b/net/ipv4/ip_tunnel.c @@ -635,6 +635,7 @@ void ip_tunnel_xmit(struct sk_buff *skb, struct net_device *dev, const struct iphdr *tnl_params, u8 protocol) { struct ip_tunnel *tunnel = netdev_priv(dev); + unsigned int inner_nhdr_len = 0; const struct iphdr *inner_iph; struct flowi4 fl4; u8 tos, ttl; @@ -644,6 +645,14 @@ void ip_tunnel_xmit(struct sk_buff *skb, struct net_device *dev, __be32 dst; bool connected; + /* ensure we can access the inner net header, for several users below */ + if (skb->protocol == htons(ETH_P_IP)) + inner_nhdr_len = sizeof(struct iphdr); + else if (skb->protocol == htons(ETH_P_IPV6)) + inner_nhdr_len = sizeof(struct ipv6hdr); + if (unlikely(!pskb_may_pull(skb, inner_nhdr_len))) + goto tx_error; + inner_iph = (const struct iphdr *)skb_inner_network_header(skb); connected = (tunnel->parms.iph.daddr != 0);