Re: WARNING in apparmor_secid_to_secctx

[Stephen Smalley]

On 08/31/2018 12:07 PM, Paul Moore wrote:
> On Fri, Aug 31, 2018 at 12:01 PM Stephen Smalley <sds@xxxxxxxxxxxxx> wrote:
> > On 08/29/2018 10:21 PM, Dmitry Vyukov wrote:
> > > On Wed, Aug 29, 2018 at 7:17 PM, syzbot
> > > <syzbot+21016130b0580a9de3b5@xxxxxxxxxxxxxxxxxxxxxxxxx> wrote:
> > > > Hello,
> > > >
> > > > syzbot found the following crash on:
> > > >
> > > > HEAD commit:    817e60a7a2bb Merge branch 'nfp-add-NFP5000-support'
> > > > git tree:       net-next
> > > > console output: https://syzkaller.appspot.com/x/log.txt?x=1536d296400000
> > > > kernel config:  https://syzkaller.appspot.com/x/.config?x=531a917630d2a492
> > > > dashboard link: https://syzkaller.appspot.com/bug?extid=21016130b0580a9de3b5
> > > > compiler:       gcc (GCC) 8.0.1 20180413 (experimental)
> > > >
> > > > Unfortunately, I don't have any reproducer for this crash yet.
> > > >
> > > > IMPORTANT: if you fix the bug, please add the following tag to the commit:
> > > > Reported-by: syzbot+21016130b0580a9de3b5@xxxxxxxxxxxxxxxxxxxxxxxxx
> > >
> > > Hi John, Tyler,
> > >
> > > I've switched syzbot from selinux to apparmor as we discussed on lss:
> > > https://github.com/google/syzkaller/commit/2c6cb254ae6c06f61e3aba21bb89ffb05b5db946
> >
> > Sorry, does this mean that you are no longer testing selinux via syzbot?
> >    That seems unfortunate.  SELinux is default-enabled and used in
> > Fedora, RHEL and all derivatives (e.g. CentOS), and mandatory in Android
> > (and seemingly getting some use in ChromeOS now as well, at least for
> > the Android container and possibly wider), so it seems unwise to drop it
> > from your testing altogether.  I was under the impression that you were
> > just going to add apparmor to your testing matrix, not drop selinux
> > altogether.
>
> It is also important to note that testing with SELinux enabled but no
> policy loaded is not going to be very helpful (last we talked that is
> what syzbot is/was doing).  While syzbot did uncover some issues
> relating to the enabled-no-policy case, those are much less
> interesting and less relevant than the loaded-policy case.

I had thought that they had switched over to at least loading a policy 
but possibly left it in permissive mode because the base distribution 
didn't properly support SELinux out of the box.  But I may be mistaken.
Regardless, the right solution is to migrate to testing with a policy 
loaded not to stop testing altogether.

Optimally, they'd test on at least one distribution/OS where SELinux is 
in fact supported out of the box, e.g. CentOS, Android, and/or ChromeOS.