Re: qemu-ga guest-exec & SELinux

["Daniel P. Berrangé" <berrange@redhat.com>]

On Tue, Jun 21, 2022 at 10:42:39AM +0200, Renaud Métrich wrote:
> Hi there,
> 
> I'm the BZ reporter.
> 
> I think the safe solution is to provide something similar to what was done
> for vmtools: have a context switching to become sort of "unconfined" domain.
> 
> This context switch has to happen only the executor and we already have a
> solution, I documented it in the BZ.
> 
> I don't think having an additional boolean is necessary, unless we want to
> restrict the commands the guest can execute.

If we allow QGA to execute arbitrary commands, running those commands
unconfined_t, then what is the point of having any SELinux policy
for QGA at all. It can just execute "/bin/sh" or "/bin/perl", passing
any script commands it wants, having them run as unconfined_t and thus
escape all SELinux confinement of QGA.

I didn't realize that we in fact already allowed runing any command
labelled bin_t. That already makes the QGA policy useless as a security
measure and should be addressed IMHO by putting that existing rul;e
behind a boolean, defaulting to disabled.

With regards,
Daniel
-- 
|: https://berrange.com      -o-    https://www.flickr.com/photos/dberrange :|
|: https://libvirt.org         -o-            https://fstop138.berrange.com :|
|: https://entangle-photo.org    -o-    https://www.instagram.com/dberrange :|