Re: [PATCH] tomoyo: Add a kernel config option for fuzzing testing.

From: Paul Moore <paul@paul-moore.com>
To: Tetsuo Handa <penguin-kernel@i-love.sakura.ne.jp>
Cc: James Morris <jmorris@namei.org>,
	linux-security-module@vger.kernel.org,
	Dmitry Vyukov <dvyukov@google.com>,
	syzbot <syzbot+29569ed06425fcf67a95@syzkaller.appspotmail.com>,
	syzbot <syzbot+e1b8084e532b6ee7afab@syzkaller.appspotmail.com>
Subject: Re: [PATCH] tomoyo: Add a kernel config option for fuzzing testing.
Date: Wed, 13 Mar 2019 09:17:57 -0400	[thread overview]
Message-ID: <CAHC9VhRMcdk5yAc0xoJ1nMfj7KAcktKmQ1GSYP2C4yRzqS9PFA@mail.gmail.com> (raw)
In-Reply-To: <8c586ed0-e9ee-a450-df06-3257cdf657ad@i-love.sakura.ne.jp>

On Wed, Mar 13, 2019 at 6:29 AM Tetsuo Handa
<penguin-kernel@i-love.sakura.ne.jp> wrote:
> On 2019/03/13 6:24, James Morris wrote:
> > On Wed, 13 Mar 2019, Tetsuo Handa wrote:
> >
> >>> I don't understand the logic here. If the cause of this is no policy
> >>> loaded combined with running out of memory, shouldn't the no-policy issue
> >>> be dealt with earlier?
> >>>
> >>
> >> This patch is for automatically loading minimal policy at boot time
> >> in order to address the no-policy issue. By applying this patch, syzbot
> >> can test TOMOYO module without modifying userspace to load TOMOYO's policy
> >> when /sbin/init starts.
> >
> > If syzbot is trying to test Tomoyo and this requires policy to be loaded,
> > shouldn't it do that?
>
> SELinux has disabled/permissive/enforcing modes.
> And syzbot is testing SELinux in permissive mode, isn't it?

I've lost track of what syzbot currently does, but in the beginning it
ran with SELinux enabled (probably in permissive mode, but that isn't
important here) without a policy loaded and that caused a handful of
problems which we have since fixed.  While it is not recommended, you
should be able to safely run a SELinux enabled system without a policy
loaded.

> TOMOYO has disabled/learning/permissive/enforcing modes.
> And syzbot will test TOMOYO in learning mode.
>
> This patch is required for telling TOMOYO to run in learning mode, by
> loading minimal policy, without asking userspace to run policy loader.
> This patch is easier than asking syzbot users to update their filesystem
> images in order to embed policy loader and minimal policy into their
> filesystem images.

-- 
paul moore
www.paul-moore.com