From 5146d1f151122e868e594c7b45115d64825aee5f Mon Sep 17 00:00:00 2001 From: Bernie Harris Date: Mon, 22 Feb 2016 12:58:05 +1300 Subject: tunnel: Clear IPCB(skb)->opt before dst_link_failure called IPCB may contain data from previous layers (in the observed case the qdisc layer). In the observed scenario, the data was misinterpreted as ip header options, which later caused the ihl to be set to an invalid value (<5). This resulted in an infinite loop in the mips implementation of ip_fast_csum. This patch clears IPCB(skb)->opt before dst_link_failure can be called for various types of tunnels. This change only applies to encapsulated ipv4 packets. The code introduced in 11c21a30 which clears all of IPCB has been removed to be consistent with these changes, and instead the opt field is cleared unconditionally in ip_tunnel_xmit. The change in ip_tunnel_xmit applies to SIT, GRE, and IPIP tunnels. The relevant vti, l2tp, and pptp functions already contain similar code for clearing the IPCB. Signed-off-by: Bernie Harris Signed-off-by: David S. Miller --- net/ipv6/ip6_gre.c | 2 ++ 1 file changed, 2 insertions(+) (limited to 'net/ipv6/ip6_gre.c') diff --git a/net/ipv6/ip6_gre.c b/net/ipv6/ip6_gre.c index a69aad1e29d1..c0d4dc1c5ea4 100644 --- a/net/ipv6/ip6_gre.c +++ b/net/ipv6/ip6_gre.c @@ -777,6 +777,8 @@ static inline int ip6gre_xmit_ipv4(struct sk_buff *skb, struct net_device *dev) __u32 mtu; int err; + memset(&(IPCB(skb)->opt), 0, sizeof(IPCB(skb)->opt)); + if (!(t->parms.flags & IP6_TNL_F_IGN_ENCAP_LIMIT)) encap_limit = t->parms.encap_limit; -- cgit v1.2.3