Jay Greguske jgregusk at
Tue Sep 3 19:37:08 UTC 2013

On 09/03/2013 01:54 PM, Daniel J Walsh wrote:
> Hash: SHA1
> On 09/03/2013 12:29 PM, Michael scherer wrote:
>> On Tue, Sep 03, 2013 at 09:48:52AM -0600, Kevin Fenzi wrote:
>>> On Tue, 03 Sep 2013 10:10:32 -0400 Jay Greguske <jgregusk at>
>>> wrote:
>>>> If we had SELinux policy enabled on the builders and used MLS on the 
>>>> chroots that would mitigate chroot-to-chroot attacks. I'm not sure if 
>>>> policy could prevent a chroot'ed process from getting access to the 
>>>> builder's certificate. If it could, I think getting SELinux working on 
>>>> the builders would be an easier path than re-writing koji to use VMs.
>>>> Maybe someone with more expertise could comment on the latter issue.
>>> In the past we had selinux disabled on the builders, as mock didn't 
>>> handle selinux very well at all and there were issues. (even in 
>>> permissive mode).
>>> With this switch to Fedora 19 for builders, we also enabled selinux in 
>>> permissive mode to gather information on any outstanding issues/avcs.
>>> Ideally I would like to get them all to enforcing and make sure we lock 
>>> down the builds as much as we are able from the vm.
>> the main issue is that mock should do the transition to a different domain
>> once it run anything in chroot. I do have a patch but I was not able to
>> make a policy for the transition ( or my patch is buggy ) and I didn't look
>> at it since a few weeks. I can send it if someone want to take a look.
> Yes The builders should run each mock with a unique MCS Label and then lock
> them down with SELinux.  I would be willing to help with this.
> This would be the easiest solution to the problem of separating out the chroots.

Are you confident we can protect the host itself from attacks from a
mock chroot?

- Jay

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