Re: NULL pointer dereference in selinux_ip_postroute_compat

From: Paul Moore
Date: Tue Aug 07 2012 - 17:50:17 EST


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

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?
* 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.

Thanks.

> Running with the following kvm line:
> kvm -nographic -smp 4 -m 1G -hda disk.img -net user -net nic,model=virtio
> -redir tcp:4400::22 -kernel ./bzImage -initrd initrd.img-1-jstultz -append
> "root=UUID=b08aa86a-4b16-488f-a3de-33c2cf335bf0 ro console=ttyS0,115200n8"
>
> Two different traces below. Config attached.

--
paul moore
www.paul-moore.com
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