Date: Tue, 18 Dec 2012 21:39:59 -0800 From: Greg KH <greg@...ah.com> To: oss-security@...ts.openwall.com Subject: Re: Plug-and-wipe and Secure Boot semantics On Tue, Dec 18, 2012 at 03:52:50PM +0100, Florian Weimer wrote: > On 12/18/2012 03:41 PM, Greg KH wrote: > >On Tue, Dec 18, 2012 at 01:46:47PM +0100, Florian Weimer wrote: > >>Some UEFI machines seem to boot from USB by default, without any > >>prompting, probably assuming that a signed boot loader cannot cause > >>any damage. > > > >Specific model name(s) please? > > Lenovo M72e 0896A9G Thanks for that, I'll try to track one down, that's a very odd behavior, but, in reading the spec, I can't see how it violates it at all. > This is a business-class Windows 8 machine which comes with a > Windows 8 logo sticker, so Secure Boot was enabled in the factory > (and my testing reflected that). I'm not sure if the type number > encodes that—Lenovo surely offers essentially the same hardware with > Secure Boot disabled by default, so that customers can install > Windows 7 more easily. > > >>Most signed Linux boot loaders only verify the kernel (and, > >>indirectly, code that's loaded into the kernel), but not the > >>initrd contents. > > > >Given that there is only one public signed Linux boot loader, saying > >"most" is a bit odd here :) > > Uhm, aren't there a couple of them in circulation? Not that I know of, all of the "public" ones are based on Matthew Gerritt's code, do you know of another one that has made it through the Microsoft signing process? > The Fedora 18 TC3 installer boots on the machine mentioned above, in > the factory default configuration. Previous installer versions > showed a Secure Boot error message. I've run into an installer bug, > though: > <https://bugzilla.redhat.com/show_bug.cgi?id=888232> Previous versions of Fedora 18 betas didn't have a valid signed bootloader to allow anything to be installed, are you sure it's all properly built now? Also, there is a bug in Matthew's signed shim code that fails on some machines (like the one I have), so you might want to work on getting the bugfix into your build/sign/distro creation process. But, more on-topic, how does UEFI secure boot have anything to do with this mailing list? thanks, greg k-h
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