On Tue, Mar 26, 2019 at 07:06:36PM -0700, Matthew Garrett wrote: > On Tue, Mar 26, 2019 at 5:31 PM Greg KH <gregkh@xxxxxxxxxxxxxxxxxxx> wrote: > > On Tue, Mar 26, 2019 at 11:27:41AM -0700, Matthew Garrett wrote: > > > From: Matthew Garrett <mjg59@xxxxxxxxxx> > > > > > > debugfs has not been meaningfully audited in terms of ensuring that > > > userland cannot trample over the kernel. At Greg's request, disable > > > access to it entirely when the kernel is locked down. This is done at > > > open() time rather than init time as the kernel lockdown status may be > > > made stricter at runtime. > > (snip) > > > Why allow all this, why not just abort the registering of the filesystem > > with the vfs core so it can't even be mounted? > > As mentioned in the commit message, because the lockdown state can be > made stricter at runtime - blocking at mount time would be > inconsistent if the machine is locked down afterwards. We could > potentially assert that it's the admin's responsibility to ensure that > debugfs isn't mounted at the point of policy being made stricter? Ugh, I can not read, sorry, neverind. The patch is fine as-is. greg k-h
