On Tue, Mar 26, 2019 at 5:31 PM Greg KH <gregkh@xxxxxxxxxxxxxxxxxxx> wrote: > > On Tue, Mar 26, 2019 at 12:20:24PM -0700, Andy Lutomirski wrote: > > On Tue, Mar 26, 2019 at 11:28 AM Matthew Garrett > > <matthewgarrett@xxxxxxxxxx> 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. > > > > Ugh. Some of those files are very useful. Could this perhaps still > > allow O_RDONLY if we're in INTEGRITY mode? > > Useful for what? Debugging, sure, but for "normal operation", no kernel > functionality should ever require debugfs. If it does, that's a bug and > should be fixed. > I semi-regularly read files in debugfs to diagnose things, and I think it would be good for this to work on distro kernels.
