Re: [PATCH] integrity: powerpc: Do not select CA_MACHINE_KEYRING

From: "Jarkko Sakkinen" <jarkko@kernel.org>
To: "Michal Suchánek" <msuchanek@suse.de>, Nayna <nayna@linux.vnet.ibm.com>
Cc: <linux-integrity@vger.kernel.org>,
	"Mimi Zohar" <zohar@linux.ibm.com>,
	"Dmitry Kasatkin" <dmitry.kasatkin@gmail.com>,
	"Paul Moore" <paul@paul-moore.com>,
	"James Morris" <jmorris@namei.org>,
	"Serge E. Hallyn" <serge@hallyn.com>,
	<linux-security-module@vger.kernel.org>,
	<linux-kernel@vger.kernel.org>, "joeyli" <jlee@suse.com>,
	"Eric Snowberg" <eric.snowberg@oracle.com>,
	"Nayna Jain" <nayna@linux.ibm.com>,
	"linuxppc-dev" <linuxppc-dev@lists.ozlabs.org>
Subject: Re: [PATCH] integrity: powerpc: Do not select CA_MACHINE_KEYRING
Date: Tue, 12 Sep 2023 12:49:52 +0300	[thread overview]
Message-ID: <CVGUFUEQVCHS.37OA20PNG9EVB@suppilovahvero> (raw)
In-Reply-To: <20230912074116.GL8826@kitsune.suse.cz>

On Tue Sep 12, 2023 at 10:41 AM EEST, Michal Suchánek wrote:
> On Mon, Sep 11, 2023 at 11:39:38PM -0400, Nayna wrote:
> > 
> > On 9/7/23 13:32, Michal Suchánek wrote:
> > > Adding more CC's from the original patch, looks like get_maintainers is
> > > not that great for this file.
> > > 
> > > On Thu, Sep 07, 2023 at 06:52:19PM +0200, Michal Suchanek wrote:
> > > > No other platform needs CA_MACHINE_KEYRING, either.
> > > > 
> > > > This is policy that should be decided by the administrator, not Kconfig
> > > > dependencies.
> > 
> > We certainly agree that flexibility is important. However, in this case,
> > this also implies that we are expecting system admins to be security
> > experts. As per our understanding, CA based infrastructure(PKI) is the
> > standard to be followed and not the policy decision. And we can only speak
> > for Power.
> > 
> > INTEGRITY_CA_MACHINE_KEYRING ensures that we always have CA signed leaf
> > certs.
>
> And that's the problem.
>
> From a distribution point of view there are two types of leaf certs:
>
>  - leaf certs signed by the distribution CA which need not be imported
>    because the distribution CA cert is enrolled one way or another
>  - user generated ad-hoc certificates that are not signed in any way,
>    and enrolled by the user
>
> The latter are vouched for by the user by enrolling the certificate, and
> confirming that they really want to trust this certificate. Enrolling
> user certificates is vital for usability or secure boot. Adding extra
> step of creating a CA certificate stored on the same system only
> complicates things with no added benefit.

This all comes down to the generic fact that kernel should not
proactively define what it *expects* sysadmins.

CA based infrastructure like anything is a policy decision not
a decision to be enforced by kernel.

BR, Jarkko