Re: [GIT PULL] MODSIGN: Use PKCS#7 for module signatures

From: Andy Lutomirski
Date: Mon Jul 27 2015 - 19:16:17 EST


On Mon, Jul 27, 2015 at 3:43 PM, David Howells <dhowells@xxxxxxxxxx> wrote:
> Andy Lutomirski <luto@xxxxxxxxxx> wrote:
>
>> With all this stuff applied, will the kernel accept PKCS#7 signatures that
>> *don't* have authenticated attributes or that are otherwise cryptographically
>> insecure in that they fail to provide the property that an attacker can't
>> manipulate a valid signature on one message to look like a valid signature on
>> a different message?
>
> Hmmm... That's easy enough to fix (see below). However, will that cause
> kexec problems, I wonder? Does mscode require authattrs?
>

Seems sensible.

How would it cause kexec problems? I can only see it being a problem
if Authenticode can't handle authattrs, right? There shouldn't be any
legacy PKCS7 kexec images whatsoever, because no existing kernel will
boot them or generate them.

--Andy
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