Re: [RFC] Second attempt at kernel secure boot support

From: Alan Cox
Date: Thu Nov 01 2012 - 10:41:32 EST


> Imagine you run windows and you've never heard of Linux.

To those people I think you mean "never heard of Ubuntu" ;-)

> In this case we have a completely 'untrusted' root inside Linux. From
> the user PoV root and Linux are both malware. Notice the EXACT same
> attack would work launching rootkit'd Linux from Linux. So don't
> pretend not to care about Windows. It's just that launching malware
> Linux seems like a reason to get your key revoked. We don't want
> signed code which can be used as an attack vector on ourselves or on
> others.
>
> That make sense?

Not really but it keeps some of the Red Hat security people happy and out
of harms way. With all the current posted RH patches I can still take over
the box as root trivially enough and you seem to have so far abolished
suspend to disk, kexec and a pile of other useful stuff. To actually lock
it down you'll have to do a ton more of this. I suspect folks who know
windows innards well are probably thinking the same about Windows 8 8)

Almost anyone attacking a secure boot box will do it via windows or more
likely via EFI. EFI because its large, new and doesn't a great history,
windows because its the larger target. Actually from what I've seen on
the security front there seems to a distinct view that secure boot is
irrelevant because Windows 8 is so suspend/resume focussed that you might
as well just trojan the box until the next reboot as its likely to be a
couple of weeks a way.

Alan




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