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Subject: Re: Firmware signing -- Re: [PATCH 00/27] security, efi: Add kernel
 lockdown
From: Mimi Zohar <zohar@linux.vnet.ibm.com>
To: Linus Torvalds <torvalds@linux-foundation.org>,
        David Howells <dhowells@redhat.com>
Cc: Alan Cox <gnomes@lxorguk.ukuu.org.uk>,
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        Matthew Garrett <mjg59@google.com>
Date: Tue, 14 Nov 2017 07:21:38 -0500
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On Mon, 2017-11-13 at 14:09 -0800, Linus Torvalds wrote:
> On Mon, Nov 13, 2017 at 1:44 PM, David Howells <dhowells@redhat.com> wrote:
> >
> > Whilst that may be true, we either have to check signatures on every bit of
> > firmware that the appropriate driver doesn't say is meant to be signed or not
> > bother.
> 
> I vote for "not bother".
> 
> Seriously, if you have firmware in /lib/firmware, and you don't trust
> it, what the hell are you doing?

I might "trust" the files in /lib/firmware, but I also want to make
sure that they haven't changed.  File signatures provide file
provenance and integrity guarantees.

Mimi