From 5146d1f151122e868e594c7b45115d64825aee5f Mon Sep 17 00:00:00 2001
From: Bernie Harris <bernie.harris@alliedtelesis.co.nz>
Date: Mon, 22 Feb 2016 12:58:05 +1300
Subject: [PATCH] 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 <bernie.harris@alliedtelesis.co.nz>
Signed-off-by: David S. Miller <davem@davemloft.net>
---
net/ipv4/ip_tunnel.c | 3 ++-
net/ipv4/udp_tunnel.c | 2 ++
net/ipv6/ip6_gre.c | 2 ++
net/ipv6/ip6_tunnel.c | 2 ++
4 files changed, 8 insertions(+), 1 deletion(-)
diff --git a/net/ipv4/ip_tunnel.c b/net/ipv4/ip_tunnel.c
index 89e8861e05fcb..336e6892a93ce 100644
--- a/net/ipv4/ip_tunnel.c
+++ b/net/ipv4/ip_tunnel.c
@@ -661,6 +661,8 @@ void ip_tunnel_xmit(struct sk_buff *skb, struct net_device *dev,
inner_iph = (const struct iphdr *)skb_inner_network_header(skb);
connected = (tunnel->parms.iph.daddr != 0);
+ memset(&(IPCB(skb)->opt), 0, sizeof(IPCB(skb)->opt));
+
dst = tnl_params->daddr;
if (dst == 0) {
/* NBMA tunnel */
@@ -758,7 +760,6 @@ void ip_tunnel_xmit(struct sk_buff *skb, struct net_device *dev,
tunnel->err_time + IPTUNNEL_ERR_TIMEO)) {
tunnel->err_count--;
- memset(IPCB(skb), 0, sizeof(*IPCB(skb)));
dst_link_failure(skb);
} else
tunnel->err_count = 0;
diff --git a/net/ipv4/udp_tunnel.c b/net/ipv4/udp_tunnel.c
index 0ec08814f37d9..96599d1a13184 100644
--- a/net/ipv4/udp_tunnel.c
+++ b/net/ipv4/udp_tunnel.c
@@ -89,6 +89,8 @@ void udp_tunnel_xmit_skb(struct rtable *rt, struct sock *sk, struct sk_buff *skb
uh->source = src_port;
uh->len = htons(skb->len);
+ memset(&(IPCB(skb)->opt), 0, sizeof(IPCB(skb)->opt));
+
udp_set_csum(nocheck, skb, src, dst, skb->len);
iptunnel_xmit(sk, rt, skb, src, dst, IPPROTO_UDP, tos, ttl, df, xnet);
diff --git a/net/ipv6/ip6_gre.c b/net/ipv6/ip6_gre.c
index a69aad1e29d1e..c0d4dc1c5ea4c 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;
diff --git a/net/ipv6/ip6_tunnel.c b/net/ipv6/ip6_tunnel.c
index 137fca42aaa6b..6c5dfec7a3779 100644
--- a/net/ipv6/ip6_tunnel.c
+++ b/net/ipv6/ip6_tunnel.c
@@ -1180,6 +1180,8 @@ ip4ip6_tnl_xmit(struct sk_buff *skb, struct net_device *dev)
u8 tproto;
int err;
+ memset(&(IPCB(skb)->opt), 0, sizeof(IPCB(skb)->opt));
+
tproto = ACCESS_ONCE(t->parms.proto);
if (tproto != IPPROTO_IPIP && tproto != 0)
return -1;
--
2.30.2