linux-kernel - Re: [PATCH v9 22/23] ima: Show owning user namespace's uid and gid when displaying policy

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Message-ID: <20220126144359.nj5p23pajme5afep@wittgenstein>
Date:   Wed, 26 Jan 2022 15:43:59 +0100
From:   Christian Brauner <brauner@...nel.org>
To:     Stefan Berger <stefanb@...ux.vnet.ibm.com>
Cc:     linux-integrity@...r.kernel.org, zohar@...ux.ibm.com,
        serge@...lyn.com, christian.brauner@...ntu.com,
        containers@...ts.linux.dev, dmitry.kasatkin@...il.com,
        ebiederm@...ssion.com, krzysztof.struczynski@...wei.com,
        roberto.sassu@...wei.com, mpeters@...hat.com, lhinds@...hat.com,
        lsturman@...hat.com, puiterwi@...hat.com, jejb@...ux.ibm.com,
        jamjoom@...ibm.com, linux-kernel@...r.kernel.org,
        paul@...l-moore.com, rgb@...hat.com,
        linux-security-module@...r.kernel.org, jmorris@...ei.org,
        Stefan Berger <stefanb@...ux.ibm.com>
Subject: Re: [PATCH v9 22/23] ima: Show owning user namespace's uid and gid
 when displaying policy

On Wed, Jan 26, 2022 at 03:43:26PM +0100, Christian Brauner wrote:
> On Tue, Jan 25, 2022 at 05:46:44PM -0500, Stefan Berger wrote:
> > From: Stefan Berger <stefanb@...ux.ibm.com>
> > 
> > Show the uid and gid values relative to the user namespace that is
> > currently active. The effect of this changes is that when one displays
> > the policy from the user namespace that originally set the policy,
> > the same uid and gid values are shown in the policy as those that were
> > used when the policy was set.
> 
> "Make sure that the uid and gid values associated with the relevant
> ima policy are resolved in the user namespace of the opener of the
> policy file."
> 
> is more correct. Also note, that by virtue of enforcing that securityfs
> files can only ever be opened if the opener's userns is the same or an
> ancestor of the userns the securityfs instance is mounted in we are
> guaranteed that the uid and gid can be resolved. That's another way of
> saying technically *_munged() isn't necessary but it is more correct
> since we're crossing the user-kernel boundary.
> 
> > 
> > Signed-off-by: Stefan Berger <stefanb@...ux.ibm.com>
> > 
> > ---

Acked-by: Christian Brauner <brauner@...nel.org>