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Date:   Wed, 10 Apr 2019 06:11:19 +1000 (AEST)
From:   James Morris <jmorris@namei.org>
To:     Kees Cook <keescook@chromium.org>
cc:     David Rheinsberg <david.rheinsberg@gmail.com>,
        John Johansen <john.johansen@canonical.com>,
        "Serge E. Hallyn" <serge@hallyn.com>,
        linux-security-module <linux-security-module@vger.kernel.org>,
        LKML <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH] apparmor: Restore Y/N in /sys for apparmor's "enabled"
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References: <20190408160706.GA18786@beast> <CADyDSO4NkEY-SPT-abnyRXT9kGWhF8LbU3XQGNp-5k_15debDg@mail.gmail.com> <CAGXu5j+g8tPrDAYVKv26ci6zvGuvC1TMXto7weVP2QBymMRjhw@mail.gmail.com>
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On Tue, 9 Apr 2019, Kees Cook wrote:

> On Mon, Apr 8, 2019 at 11:21 PM David Rheinsberg
> <david.rheinsberg@gmail.com> wrote:
> >
> > Hi
> >
> > On Mon, Apr 8, 2019 at 6:07 PM Kees Cook <keescook@chromium.org> wrote:
> > >
> > > Before commit c5459b829b71 ("LSM: Plumb visibility into optional "enabled"
> > > state"), /sys/module/apparmor/parameters/enabled would show "Y" or "N"
> > > since it was using the "bool" handler. After being changed to "int",
> > > this switched to "1" or "0", breaking the userspace AppArmor detection
> > > of dbus-broker. This restores the Y/N output while keeping the LSM
> > > infrastructure happy.
> > >
> > > Before:
> > >         $ cat /sys/module/apparmor/parameters/enabled
> > >         1
> > >
> > > After:
> > >         $ cat /sys/module/apparmor/parameters/enabled
> > >         Y
> > >
> > > Reported-by: David Rheinsberg <david.rheinsberg@gmail.com>
> > > Link: https://lkml.kernel.org/r/CADyDSO6k8vYb1eryT4g6+EHrLCvb68GAbHVWuULkYjcZcYNhhw@mail.gmail.com
> > > Fixes: c5459b829b71 ("LSM: Plumb visibility into optional "enabled" state")
> > > Signed-off-by: Kees Cook <keescook@chromium.org>
> > > ---
> > > This fix, if John is okay with it, is needed in v5.1 to correct the
> > > userspace regression reported by David.
> > > ---
> > >  security/apparmor/lsm.c | 49 ++++++++++++++++++++++++++++++++++++++++-
> > >  1 file changed, 48 insertions(+), 1 deletion(-)
> >
> > This looks good to me. Thanks a lot! If this makes v5.1, I will leave
> > the apparmor-detection in dbus-broker as it is, unless someone asks me
> > to parse 0/1 as well?
> >
> > I cannot judge whether the apparmor_initialized check is correct, but
> > for the parameter parsing:
> >
> > Reviewed-by: David Rheinsberg <david.rheinsberg@gmail.com>
> 
> Thanks!
> 
> James, are you able to take this for v5.1 fixes?

Sure.

-- 
James Morris
<jmorris@namei.org>