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ip_tunnel: fix kernel panic with icmp_dest_unreach

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[ Upstream commit a622260254 ]

Daniel Petre reported crashes in icmp_dst_unreach() with following call
graph:

Daniel found a similar problem mentioned in
 http://lkml.indiana.edu/hypermail/linux/kernel/1007.0/00961.html

And indeed this is the root cause : skb->cb[] contains data fooling IP
stack.

We must clear IPCB in ip_tunnel_xmit() sooner in case dst_link_failure()
is called. Or else skb->cb[] might contain garbage from GSO segmentation
layer.

A similar fix was tested on linux-3.9, but gre code was refactored in
linux-3.10. I'll send patches for stable kernels as well.

Many thanks to Daniel for providing reports, patches and testing !

Reported-by: Daniel Petre <daniel.petre@rcs-rds.ro>
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Eric Dumazet 2013-05-24 05:49:58 +00:00 committed by Greg Kroah-Hartman
parent fa17eb7500
commit 3c353df4ca
2 changed files with 2 additions and 2 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

2
net/ipv4/ip_gre.c
View File

@ -722,6 +722,7 @@ static netdev_tx_t ipgre_tunnel_xmit(struct sk_buff *skb, struct net_device *dev
tiph = &tunnel->parms.iph;
}
memset(&(IPCB(skb)->opt), 0, sizeof(IPCB(skb)->opt));
if ((dst = tiph->daddr) == 0) {
/* NBMA tunnel */
@ -865,7 +866,6 @@ static netdev_tx_t ipgre_tunnel_xmit(struct sk_buff *skb, struct net_device *dev
skb_reset_transport_header(skb);
skb_push(skb, gre_hlen);
skb_reset_network_header(skb);
memset(&(IPCB(skb)->opt), 0, sizeof(IPCB(skb)->opt));
IPCB(skb)->flags &= ~(IPSKB_XFRM_TUNNEL_SIZE | IPSKB_XFRM_TRANSFORMED |
IPSKB_REROUTED);
skb_dst_drop(skb);

2
net/ipv4/ipip.c
View File

@ -448,6 +448,7 @@ static netdev_tx_t ipip_tunnel_xmit(struct sk_buff *skb, struct net_device *dev)
if (tos & 1)
tos = old_iph->tos;
memset(&(IPCB(skb)->opt), 0, sizeof(IPCB(skb)->opt));
if (!dst) {
/* NBMA tunnel */
if ((rt = skb_rtable(skb)) == NULL) {
@ -530,7 +531,6 @@ static netdev_tx_t ipip_tunnel_xmit(struct sk_buff *skb, struct net_device *dev)
skb->transport_header = skb->network_header;
skb_push(skb, sizeof(struct iphdr));
skb_reset_network_header(skb);
memset(&(IPCB(skb)->opt), 0, sizeof(IPCB(skb)->opt));
IPCB(skb)->flags &= ~(IPSKB_XFRM_TUNNEL_SIZE | IPSKB_XFRM_TRANSFORMED |
IPSKB_REROUTED);
skb_dst_drop(skb);