Re: [PATCH 5/9] Make use of permissions, returned by kobj_lookup

[Greg KH <greg@kroah.com>]

On Sat, Mar 08, 2008 at 03:47:57PM -0600, Serge E. Hallyn wrote:
> Quoting Greg KH (greg@kroah.com):
> > On Fri, Mar 07, 2008 at 12:50:52PM -0600, Serge E. Hallyn wrote:
> > > Quoting Greg KH (greg@kroah.com):
> > > > On Fri, Mar 07, 2008 at 11:35:42AM -0600, Serge E. Hallyn wrote:
> > > > > > Do you really want to run other LSMs within a containerd kernel?  Is
> > > > > > that a requirement?  It would seem to run counter to the main goal of
> > > > > > containers to me.
> > > > > 
> > > > > Until user namespaces are complete, selinux seems the only good solution
> > > > > to offer isolation.
> > > > 
> > > > Great, use that instead :)
> > > 
> > > That can't work as is since you can't specify major:minor in policy.
> > 
> > Your LSM can not, or the LSM interface does not allow this to happen?
> 
> No my lsm in fact does, you just can't do it with selinux policy at the
> moment.  I was still responding to your "just use selinux" :)

I never said "use selinux", do you think I am crazy?  :)

Just use your own lsm, that's all I recommended.

> > > So all we could do again is simply refuse all mknod, which we can
> > > already do with per-process capability bounding sets.
> > 
> > I thought we passed that info down to the LSM module, can't you do your
> > selection at that point in time?
> > 
> > And then, just mediate open() like always, right?
> 
> Yup, the patch I included inline does that.

Great.  But don't put that other file in the core kernel, put it in
security/ please.

> An LSM can address the problem.  It just felt like more of a
> patch-over-the-real-problem kind of solution.

I disagree, it sounds exactly like what LSM is for.

thanks,

greg k-h