linux-kernel - Re: [BUG] Race between policy reload sidtab conversion and live conversion

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Message-ID: <20210223223652.GD6000@sequoia>
Date:   Tue, 23 Feb 2021 16:36:52 -0600
From:   Tyler Hicks <tyhicks@...ux.microsoft.com>
To:     Paul Moore <paul@...l-moore.com>,
        Stephen Smalley <stephen.smalley.work@...il.com>,
        Ondrej Mosnacek <omosnace@...hat.com>
Cc:     selinux@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [BUG] Race between policy reload sidtab conversion and live
 conversion

On 2021-02-23 15:50:56, Tyler Hicks wrote:
> On 2021-02-23 15:43:48, Tyler Hicks wrote:
> > I'm seeing a race during policy load while the "regular" sidtab
> > conversion is happening and a live conversion starts to take place in
> > sidtab_context_to_sid().
> > 
> > We have an initial policy that's loaded by systemd ~0.6s into boot and
> > then another policy gets loaded ~2-3s into boot. That second policy load
> > is what hits the race condition situation because the sidtab is only
> > partially populated and there's a decent amount of filesystem operations
> > happening, at the same time, which are triggering live conversions.

Hmm, perhaps this is the same problem that's fixed by Ondrej's proposed
change here:

 https://lore.kernel.org/selinux/20210212185930.130477-3-omosnace@redhat.com/

I'll put these changes through a validation run (the only place that I
can seem to reproduce this crash) and see how it looks.

Tyler