tunnel: Clear IPCB(skb)->opt before dst_link_failure called

[ Upstream commit 5146d1f151122e868e594c7b45115d64825aee5f ]

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>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/net/ipv4/ip_tunnel.c b/net/ipv4/ip_tunnel.c
index cbb51f3fac06c66e76204957b3243f50a58384b4..ce30c8b72457fd425438ca675ff42cdd67e17505 100644 (file)
--- a/net/ipv4/ip_tunnel.c
+++ b/net/ipv4/ip_tunnel.c
@@ -663,6 +663,8 @@ 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 */
@@ -760,7 +762,6 @@ 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 aba428626b5290ddf68c8b350b8b2879119d136b..280a9bdeddeeaad5dcbf3181e02cae946403e44d 100644 (file)
--- a/net/ipv4/udp_tunnel.c
+++ b/net/ipv4/udp_tunnel.c
@@ -89,6 +89,8 @@ int 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);
 
        return iptunnel_xmit(sk, rt, skb, src, dst, IPPROTO_UDP,

diff --git a/net/ipv6/ip6_gre.c b/net/ipv6/ip6_gre.c
index e5ea177d34c6492713d5271032394a69874a300c..4650c6824783ea29f687780aa61669a82e889858 100644 (file)
--- a/net/ipv6/ip6_gre.c
+++ b/net/ipv6/ip6_gre.c
@@ -778,6 +778,8 @@ 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 137fca42aaa6bb809d46e7809b240d8810d89a04..6c5dfec7a3779601eb760eeeb975ae5e6db00bb7 100644 (file)
--- 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;