Re: NULL pointer dereference in selinux_ip_postroute_compat

[John Stultz]

On 08/07/2012 03:01 PM, Paul Moore wrote:
> On Tue, Aug 7, 2012 at 5:58 PM, John Stultz <john.stultz@xxxxxxxxxx> wrote:
> > On 08/07/2012 02:50 PM, Paul Moore wrote:
> > > On Tue, Aug 7, 2012 at 2:12 PM, John Stultz <john.stultz@xxxxxxxxxx>
> > > wrote:
> > > > Hi,
> > > >       With my kvm environment using 3.6-rc1+, I'm seeing NULL pointer
> > > > dereferences in selinux_ip_postroute_compat(). It looks like the sksec
> > > > value
> > > > is null and we die in the following line:
> > > >
> > > >       if (selinux_xfrm_postroute_last(sksec->sid, skb, &ad, proto))
> > > >
> > > > This triggers every time I shutdown the machine, but has also triggered
> > > > randomly after a few hours.
> > > >
> > > > This is on an ubuntu 12.04 image, not using selinux.
> > > NOTE: Adding the SELinux list to the CC line
> > Thanks!
> >
> > > Hi,
> > >
> > > I'm trying to understand this and I was hoping you could you clarify a
> > > few things for me:
> > >
> > > * Is the panic in the Ubuntu 12.04 guest, or the host?  If the host,
> > > could you share what distribution you are using?
> > Sorry, its a 12.04 guest.  I think the host is Ubuntu 12.04 as well.
> >
> >
> > > * When you say you are not using SELinux, could you be more specific?
> > > It seems odd that you are not using SELinux but the panic is happening
> > > in a SELinux hook.
> > I just mean that, being Ubuntu,  the system (userland) isn't configured to
> > use selinux.  SELinux is just enabled in the kernel config.
> Thanks for the quick response, I'll setup an Ubuntu guest and see if I
> can reproduce this ... something is odd.  Anything non-standard about
> your guest install or anything else you think might be helpful?
Don't think so.  Just a standard 64bit ubuntu 12.04 install.

Since I'm booting kernel/initrd from the commandline, the initrd *may* 
be older then 12.04, I can't quite remember when I copied that out of 
the image. I'll see if it still triggers if I copy the current initrd out.

thanks
-john

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