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. thanks, greg k-h
