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Subject: Re: WARNING in apparmor_secid_to_secctx
To:     Dmitry Vyukov <dvyukov@google.com>
Cc:     Casey Schaufler <casey@schaufler-ca.com>,
        Paul Moore <paul@paul-moore.com>,
        Stephen Smalley <sds@tycho.nsa.gov>,
        syzbot <syzbot+21016130b0580a9de3b5@syzkaller.appspotmail.com>,
        tyhicks@canonical.com, John Johansen <john.johansen@canonical.com>,
        James Morris <jmorris@namei.org>,
        LKML <linux-kernel@vger.kernel.org>,
        linux-security-module@vger.kernel.org,
        Serge Hallyn <serge@hallyn.com>,
        syzkaller-bugs <syzkaller-bugs@googlegroups.com>,
        Jeffrey Vander Stoep <jeffv@google.com>,
        SELinux <selinux@tycho.nsa.gov>,
        Russell Coker <russell@coker.com.au>,
        Laurent Bigonville <bigon@debian.org>,
        syzkaller <syzkaller@googlegroups.com>
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From:   Tetsuo Handa <penguin-kernel@i-love.sakura.ne.jp>
Message-ID: <71e3652b-b222-0c3f-8b48-5980ddcaeb93@i-love.sakura.ne.jp>
Date:   Fri, 1 Feb 2019 19:43:39 +0900
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On 2019/02/01 19:09, Dmitry Vyukov wrote:
> Thanks for the explanations.
>
> Here is the change that I've come up with:
> https://github.com/google/syzkaller/commit/aa53be276dc84aa8b3825b3416542447ff82b41a

You are not going to apply this updated config to upstream kernels now, are you?
Removing CONFIG_DEFAULT_SECURITY="apparmor" from configs used by upstream kernels
will cause failing to enable AppArmor (unless security=apparmor is specified).

I guess you can apply this updated config to linux-next kernels given that
you replace

  CONFIG_LSM="yama,loadpin,safesetid,integrity,selinux,smack,tomoyo,apparmor"

with

  CONFIG_LSM="yama,loadpin,safesetid,integrity,apparmor,selinux,smack,tomoyo"

so that AppArmor is enabled instead of SELinux.

>
> I've disabled CONFIG_SECURITY_TOMOYO_OMIT_USERSPACE_LOADER (it
> actually looked like omitting a user-space loader that I don't have is
> the right thing to do, but okay, it indeed does not with =y).
>
> For now I just enabled TOMOYO and SAFESETID.
> I see the problem with making both linux-next and upstream work. If we
> use a single config and lsm= cmdline argument, then on upstream all
> kernels will use the same module (they won't understand lsm=). But if
> we add security= then it will take precedence over lsm= on linux-next,
> so we won't get stacked modules.

Right.

>
> Let's go with (c) because I don't want an additional long-term maintenance cost.

OK.

> If I understand it correctly later we will need to replace:
> security=selinux
> security=smack
> security=apparmor
>
> with:
> lsm=yama,safesetid,integrity,selinux,tomoyo
> lsm=yama,safesetid,integrity,smack,tomoyo
> lsm=yama,safesetid,integrity,tomoyo,apparmor

Yes. Thank you.