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Date:   Wed, 3 Aug 2022 18:25:18 +0000
From:   Eric Biggers <ebiggers@kernel.org>
To:     Daniil Lunev <dlunev@chromium.org>
Cc:     Zdenek Kabelac <zdenek.kabelac@gmail.com>,
        Brian Geffon <bgeffon@google.com>,
        Mike Snitzer <snitzer@kernel.org>,
        linux-kernel@vger.kernel.org, dm-devel@redhat.com,
        Mikulas Patocka <mpatocka@redhat.com>,
        Alasdair Kergon <agk@redhat.com>
Subject: Re: [dm-devel] [PATCH 1/1] dm: add message command to disallow
 device open
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On Wed, Aug 03, 2022 at 02:29:40PM +1000, Daniil Lunev wrote:
> > This seems like an access control policy, which the Linux kernel already has a
> > lot of mechanisms for.  Chrome OS already uses SELinux.  Couldn't this be solved
> > by giving the device node an SELinux label that no one has permission to open?
> That would be the ideal solution, but there is a number of challenges
> that prevent
> us enabling enforcement on all SELinux domains unfortunately. While in the long
> run that would be a preferred option, in the short run this doesn't
> seem feasible. I
> would assume the problem of enabling full SELInux enforcement would plague
> any big project that didn't have them enabled from the get going.
> --Daniil

Have you also considered unlinking the device node (/dev/dm-$idx) from the
filesystem after it has been set up for swap?

- Eric