Re: [PATCH 0/5] MODSIGN: Use PKCS#7 for module signatures

From: David Howells <dhowells@redhat.com>
To: Dmitry Kasatkin <d.kasatkin@samsung.com>
Cc: dhowells@redhat.com, mmarek@suse.cz, rusty@rustcorp.com.au,
	vgoyal@redhat.com, keyrings@linux-nfs.org,
	linux-security-module@vger.kernel.org, zohar@linux.vnet.ibm.com,
	linux-kernel@vger.kernel.org
Subject: Re: [PATCH 0/5] MODSIGN: Use PKCS#7 for module signatures
Date: Mon, 24 Nov 2014 12:51:31 +0000	[thread overview]
Message-ID: <14251.1416833491@warthog.procyon.org.uk> (raw)
In-Reply-To: <547325A2.7070408@samsung.com>

Dmitry Kasatkin <d.kasatkin@samsung.com> wrote:

> >  (2) Makes use of the PKCS#7 facility to provide module signatures.
> >
> >      sign-file is replaced with a program that generates a PKCS#7 message
> >      that has no X.509 certs embedded and that has detached data (the
> >      module content) and adds it onto the message with magic string and
> >      descriptor.
> 
> Why do you highlight that X509 is not embedded?
> Current module signing does not embed X509 also.

A PKCS#7 message can have X.509 certs embedded within it - but it's optional
within the spec.  Given that we expect to have the appropriate cert available
to verify the signature on the PKCS#7 message directly, there's no need to
actually embed the X.509 cert therein.

Unfortunately, it doesn't appear that you can do this with the openssl command
line utility - hence why I moved to C.

David