Date: Tue, 06 Nov 2012 08:01:16 +0100
Message-ID: <s5ha9uvi5ab.wl%tiwai@suse.de>
From: Takashi Iwai <tiwai@suse.de>
To: David Howells <dhowells@redhat.com>
Cc: Matthew Garrett <mjg59@srcf.ucam.org>, Alan Cox <alan@lxorguk.ukuu.org.uk>,
        joeyli <jlee@suse.com>, Jiri Kosina <jkosina@suse.cz>,
        Rusty Russell <rusty@rustcorp.com.au>, linux-kernel@vger.kernel.org,
        linux-security-module@vger.kernel.org, linux-efi@vger.kernel.org
Subject: Re: [PATCH RFC 0/4] Add firmware signature file check
In-Reply-To: <5839.1352160112@warthog.procyon.org.uk>
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At Tue, 06 Nov 2012 00:01:52 +0000,
David Howells wrote:
> 
> Takashi Iwai <tiwai@suse.de> wrote:
> 
> > this is a patch series to add the support for firmware signature
> > check.  At this time, the kernel checks extra signature file (*.sig)
> > for each firmware, instead of embedded signature.
> > It's just a quick hack using the existing module signing mechanism,
> > thus provided only as a proof of concept for now.
> 
> There is another way to do this.  If you look at the patches I proposed to
> wrap keys in PE binaries, you'll find that that can handle PKCS#7 format
> messages as that's what's in the sort of signed PE binary we're dealing with.
> 
> You could use this to put the firmware inside a signed-data PKCS#7 message.

Yeah, embedding the signature is more straightforward.  Actually I
tried the embedded signature (just like module) at first, then a
couple of concerns arose:

- Legally unclear about "modifying" the firmware data or file,

- The signed firmware is no longer compatible with the older kernel,
  thus bad for distro packaging.


thanks,

Takashi
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