Half-OT: Secure boot and thirdy party kernel modules

[Florian Weimer]

On 07/08/2014 10:19 AM, Petr Pisar wrote:
> On 2014-07-07, Florian Weimer <fweimer at redhat.com> wrote:
>> Note that Microsoft's current policy may not allow unrestricted
>> virtualization (KVM or Virtualbox—does not matter) because that "permits
>> launch of another operating system instance after execution of
>> unauthenticated code"—the wording is rather unclear.  If Microsoft
>> clarifies that this is forbidden, a future Fedora update will remove
>> this functionality, so you will be forced to disable Secure Boot at this
>> point anyway if you want to continue to use virtualization.

> Could you elaborate more what "unauthenticated code" is in this case?

I think it's code that is not cryptographically tied (indirectly) to one 
of the Secure Boot trust roots.

However, I don't really know what Microsoft means.  It's conceivable 
that they assume we sign all of user space (not just for installation 
purposes), and they might have a wrong idea about what we can implement 
in our system.

> Is
> it a userspace tool for controlling in-kernel virtualization (e.g. qemu
> in case of KVM)? Because KVM as a kernel module is signed.

It's unclear.  One possible interpretation is that virtualization acts 
as a barrier because it does not provide access to "real" ring 0 on the 
host.  It sounds reasonable, but it doesn't really match Microsoft's 
wording I quoted above (from a public blog post).

-- 
Florian Weimer / Red Hat Product Security