On Wed, Apr 4, 2018 at 6:52 AM Theodore Y. Ts'o <ty...@mit.edu> wrote:
> On Wed, Apr 04, 2018 at 02:33:37PM +0100, David Howells wrote: > > Theodore Y. Ts'o <ty...@mit.edu> wrote: > > > > > Whoa. Why doesn't lockdown prevent kexec? Put another away, why > > > isn't this a problem for people who are fearful that Linux could be > > > used as part of a Windows boot virus in a Secure UEFI context? > > > > Lockdown mode restricts kexec to booting an authorised image (where the > > authorisation may be by signature or by IMA). > If that's true, then Matthew's assertion that lockdown w/o secure boot > is insecure goes away, no? If you don't have secure boot then an attacker with root can modify your bootloader or kernel, and on next boot lockdown can be silently disabled.