Re: [PATCH 14/16] X.509: Add an ASN.1 decoder

[Peter Jones]

On Tue, 2012-09-18 at 19:51 +0100, Alan Cox wrote:
> On Tue, 18 Sep 2012 18:34:12 +0100
> David Howells <dhowells@xxxxxxxxxx> wrote:
> 
> > Alan Cox <alan@xxxxxxxxxxxxxxxxxxx> wrote:
> > 
> > > Why do this in the kernel.That appears to be completely insane.
> > 
> > A number of reasons:
> > 
> >  (1) The UEFI signature/key database may contain ASN.1 X.509 certificates and
> >      we may need to use those very early in the boot process, during initrd.
> 
> Ok that makes some sense. Presumably they've also got to fall within what
> you trust and sign ?

The idea is that you implicitly trust keys in the lists maintained by
your system firmware and/or shim ("mok") key databases, or else you
shouldn't have Secure Boot turned on in the first place.  Using these
keys and hashes allows you to e.g. relatively easily add a key you're
using to sign a module you're currently developing, while still *ahem*
enjoying the many benefits of signed modules, kernel, and bootloader.

(Though obviously we would never recommend adding a public key whose
private half you're normally keeping on that same machine.)

-- 
  Peter

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