> On Mon 2008-03-31 09:00:53, Serge E. Hallyn wrote:
> > Quoting Pavel Machek (
pavel@ucw.cz):
> > > On Wed 2008-03-26 13:05:43, Serge E. Hallyn wrote:
> > > > (This is identical to the version I sent on Mar 19 in response to
> > > > the comments by Daniel Hokka Zakrisson, which are the last
> > > > comments I've gotten.)
> > > >
> > > > Implement a cgroup to track and enforce open and mknod restrictions on device
> > > > files. A device cgroup associates a device access whitelist with each
> > > > cgroup. A whitelist entry has 4 fields. 'type' is a (all), c (char), or
> > > > b (block). 'all' means it applies to all types and all major and minor
> > > > numbers. Major and minor are either an integer or * for all.
> > > > Access is a composition of r (read), w (write), and m (mknod).
> > > >
> > > > The root device cgroup starts with rwm to 'all'. A child devcg gets
> > > > a copy of the parent. Admins can then remove devices from the
> > > > whitelist or add new entries. A child cgroup can never receive a
> > > > device access which is denied its parent. However when a device
> > > > access is removed from a parent it will not also be removed from the
> > > > child(ren).
> > > >
> > > > An entry is added using devices.allow, and removed using
> > > > devices.deny. For instance
> > > >
> > > > echo 'c 1:3 mr' > /cgroups/1/devices.allow
> > > >
> > > > allows cgroup 1 to read and mknod the device usually known as
> > > > /dev/null. Doing
> > > >
> > > > echo a > /cgroups/1/devices.deny
> > >
> > > Can't you use selinux or something?
> >
> > No. At the moment SELinux can't authorize based on type/major:minor. I
> > would like to add that support later on, but even when I do, folks such
> > as the openvz folks do not want to rely on any security modules.
>
> Yep, it looks like openvz folks do not want to rely on any security
> modules, do not want to fix their userland, and do not have a taste
> when implementing new features.
>
> IMO that means openvz folks should be kept off mainline.
>
> Implementing SELinux extension that can authorize based on
> type/major:minor seems like a way to go to me....
