diff options
authorPaolo Abeni <pabeni@redhat.com>2018-09-24 15:48:19 +0200
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2018-10-20 09:52:36 +0200
commitf9d3572816ba724129da0ec2ecd590d5c899e86e (patch)
parent20f16d1a3817523350e9c5b5a231c4cb2cf0ab3f (diff)
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 <xiyou.wangcong@gmail.com> Signed-off-by: Paolo Abeni <pabeni@redhat.com> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
1 files changed, 9 insertions, 0 deletions
diff --git a/net/ipv4/ip_tunnel.c b/net/ipv4/ip_tunnel.c
index 3d62feb65932..9d3176b080a4 100644
--- a/net/ipv4/ip_tunnel.c
+++ b/net/ipv4/ip_tunnel.c
@@ -597,6 +597,7 @@ 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;
@@ -607,6 +608,14 @@ void ip_tunnel_xmit(struct sk_buff *skb, struct net_device *dev,
int err;
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);