[PATCH 5/5] drm: drop DRM_AUTH from PRIME_TO/FROM_HANDLE ioctls

[Daniel Vetter]

On Wed, Nov 27, 2019 at 06:32:56PM +0000, Emil Velikov wrote:
> On Wed, 27 Nov 2019 at 18:04, Daniel Vetter <daniel at ffwll.ch> wrote:
> >
> > On Wed, Nov 27, 2019 at 04:27:29PM +0000, Emil Velikov wrote:
> > > On Wed, 27 Nov 2019 at 07:41, Boris Brezillon
> > > <boris.brezillon at collabora.com> wrote:
> > > >
> > > > Hi Emil,
> > > >
> > > > On Fri,  1 Nov 2019 13:03:13 +0000
> > > > Emil Velikov <emil.l.velikov at gmail.com> wrote:
> > > >
> > > > > From: Emil Velikov <emil.velikov at collabora.com>
> > > > >
> > > > > As mentioned by Christian, for drivers which support only primary nodes
> > > > > this changes the returned error from -EACCES into -EOPNOTSUPP/-ENOSYS.
> > > >
> > > > Are you sure this is true for MODESET-only nodes (those that do not
> > > > have the RENDER cap set) implementing ->{fd_to_handle,handle_to_fd}()?
> > > > Shouldn't the is_authenticated() check still be done in that case?
> > > >
> > > Thanks for catching this. Just sent out v2, which I should address the concern.
> >
> > Why do we need this additional check in v2? What can go wrong on modeset
> > drivers if non-authenticated legacy things can use this? modeset-only
> > drivers have all their resources segregated by the drm core (drm_fb,
> > mmaps, buffer lists), so there's really no access limitations that can go
> > wrong here.
> 
> Welcome back Daniel.
> 
> I haven't audited the core drm code, so wasn't sure if there's any
> issues that may arise.
> Hence the conservative approach in v2.
> 
> If you think this is fine as-is a formal Reviewed-by would be highly
> appreciated.

I think there's a non-zero chance I'll have to eat a few hats on this, but
I think v1 is solid.

Reviewed-by: Daniel Vetter <daniel.vetter at ffwll.ch>

> 
> Thanks
> Emil

-- 
Daniel Vetter
Software Engineer, Intel Corporation
http://blog.ffwll.ch