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Date: Fri, 6 Apr 2007 22:40:20 -0500
From: "Eric Van Hensbergen" <ericvh@gmail.com>
To: "H. Peter Anvin" <hpa@zytor.com>
Subject: Re: [patch 0/8] unprivileged mount syscall
Cc: "Jan Engelhardt" <jengelh@linux01.gwdg.de>,
       "Andrew Morton" <akpm@linux-foundation.org>,
       "Miklos Szeredi" <miklos@szeredi.hu>, linux-fsdevel@vger.kernel.org,
       util-linux-ng@vger.kernel.org, containers@lists.osdl.org,
       linux-kernel@vger.kernel.org
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On 4/6/07, H. Peter Anvin <hpa@zytor.com> wrote:
> Jan Engelhardt wrote:
> > On Apr 6 2007 16:16, H. Peter Anvin wrote:
> >>>> - users can use bind mounts without having to pre-configure them in
> >>>> /etc/fstab
> >>>>
> >> This is by far the biggest concern I see.  I think the security implication of
> >> allowing anyone to do bind mounts are poorly understood.
> >
> > $ whoami
> > miklos
> > $ mount --bind / ~/down_under
> >
> > later that day:
> > # userdel -r miklos
> >
>
> Consider backups, for example.
>

This is the reason why enforcing private namespaces for user mounts
makes sense.  I think it catches many of these corner cases.

          -eric