diff mbox

BUG: MARK in OUTPUT + ip_tunnel causes kernel panic

Message ID 20130925085947.GY7660@secunet.com
State RFC, archived
Delegated to: David Miller
Headers show

Commit Message

Steffen Klassert Sept. 25, 2013, 8:59 a.m. UTC 
On Wed, Sep 25, 2013 at 08:31:52AM +0000, Konstantin Kuzov wrote:
> Kristian Evensen <kristian.evensen <at> gmail.com> writes:
> 
> > When trying to tunnel traffic originating from the same machine as the
> > tunnel endpoint, I am experiencing kernel panics for some types of
> > traffic (ICMP and UDP). TCP seems not to be affected by this, at least
> > I have not been able to trigger the panic.
> > 
> > I have one tunnel (without an IP address) and use policy routing to
> > steer some traffic through the tunnels.
> [...]
> > An interesting thing is that I have seen different kernel panics being
> > triggered. The other one I have seen has RIP pointing to
> > e1000_xmit_frame() and the message "protocol 0800 is buggy". However,
> > the one I have posted is by far the most common.
> I'm experiencing the same issue on two different machines. It happens on any 
> kernel starting from 3.10 when ip_tunnel/ip_tunnel_core were introduced.
> 

Can you please try the patch below?
I've posted the same patch already to netdev in the morning.

Subject: [PATCH net 1/2] ip_tunnel: Fix a memory corruption in ip_tunnel_xmit

We might extend the used aera of a skb beyond the total
headroom when we install the ipip header. Fix this by
calling skb_cow_head() unconditionally.

Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com>
---
 net/ipv4/ip_tunnel.c |   12 ++++++------
 1 file changed, 6 insertions(+), 6 deletions(-)

Comments

Konstantin Kuzov Sept. 26, 2013, 2:06 a.m. UTC | #1 
On Wed, 25 Sep 2013 10:59:47 +0200
Steffen Klassert wrote:

 > > > When trying to tunnel traffic originating from the same machine as the
 > > > tunnel endpoint, I am experiencing kernel panics for some types of
 > > > traffic (ICMP and UDP). TCP seems not to be affected by this, at least
 > > > I have not been able to trigger the panic.
 > > > 
 > > > I have one tunnel (without an IP address) and use policy routing to
 > > > steer some traffic through the tunnels.  
 > > [...]  
 > > > An interesting thing is that I have seen different kernel panics being
 > > > triggered. The other one I have seen has RIP pointing to
 > > > e1000_xmit_frame() and the message "protocol 0800 is buggy". However,
 > > > the one I have posted is by far the most common.  
 > > I'm experiencing the same issue on two different machines. It happens on any 
 > > kernel starting from 3.10 when ip_tunnel/ip_tunnel_core were introduced.
 > >   
 > Can you please try the patch below?
 > I've posted the same patch already to netdev in the morning.
 > 
 > Subject: [PATCH net 1/2] ip_tunnel: Fix a memory corruption in ip_tunnel_xmit  
 
Thank you very much. All works fine with that patch applied.

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Kristian Evensen Sept. 26, 2013, 6:27 p.m. UTC | #2 
On Wed, Sep 25, 2013 at 10:59 AM, Steffen Klassert
<steffen.klassert@secunet.com> wrote:
> Can you please try the patch below?
> I've posted the same patch already to netdev in the morning.

Thank you very much for this patch. I am currently travelling, but
will give it a try when I am back in the office next week.

-Kristian
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diff mbox

Patch

diff --git a/net/ipv4/ip_tunnel.c b/net/ipv4/ip_tunnel.c
index ac9fabe..b8ce640 100644
--- a/net/ipv4/ip_tunnel.c
+++ b/net/ipv4/ip_tunnel.c
@@ -641,13 +641,13 @@  void ip_tunnel_xmit(struct sk_buff *skb, struct net_device *dev,
 
 	max_headroom = LL_RESERVED_SPACE(rt->dst.dev) + sizeof(struct iphdr)
 			+ rt->dst.header_len;
-	if (max_headroom > dev->needed_headroom) {
+	if (max_headroom > dev->needed_headroom)
 		dev->needed_headroom = max_headroom;
-		if (skb_cow_head(skb, dev->needed_headroom)) {
-			dev->stats.tx_dropped++;
-			dev_kfree_skb(skb);
-			return;
-		}
+
+	if (skb_cow_head(skb, dev->needed_headroom)) {
+		dev->stats.tx_dropped++;
+		dev_kfree_skb(skb);
+		return;
 	}
 
 	err = iptunnel_xmit(rt, skb, fl4.saddr, fl4.daddr, protocol,