Re: Re: [PATCH 2/2] sysctl: allow CLONE_NEWUSER
to be disabled
[Posted January 26, 2016 by corbet]
| From: |
| Ben Hutchings <ben-AT-decadent.org.uk> |
| To: |
| kernel-hardening-AT-lists.openwall.com, Robert Święcki <robert-AT-swiecki.net>, "Serge E. Hallyn" <serge.hallyn-AT-ubuntu.com> |
| Subject: |
| Re: Re: [PATCH 2/2] sysctl: allow CLONE_NEWUSER to be disabled |
| Date: |
| Sat, 23 Jan 2016 00:59:59 +0000 |
| Message-ID: |
| <1453510799.3734.153.camel@decadent.org.uk> |
| Cc: |
| Andrew Morton <akpm-AT-linux-foundation.org>, Al Viro <viro-AT-zeniv.linux.org.uk>, Richard Weinberger <richard-AT-nod.at>, "Eric W. Biederman" <ebiederm-AT-xmission.com>, Andy Lutomirski <luto-AT-amacapital.net>, Dmitry Vyukov <dvyukov-AT-google.com>, David Howells <dhowells-AT-redhat.com>, Kostya Serebryany <kcc-AT-google.com>, Alexander Potapenko <glider-AT-google.com>, Eric Dumazet <edumazet-AT-google.com>, Sasha Levin <sasha.levin-AT-oracle.com>, "linux-doc-AT-vger.kernel.org" <linux-doc-AT-vger.kernel.org>, LKML <linux-kernel-AT-vger.kernel.org> |
| Archive‑link: | |
Article |
On Fri, 2016-01-22 at 15:00 -0800, Kees Cook wrote:
> On Fri, Jan 22, 2016 at 2:55 PM, Robert Święcki <robert@swiecki.net> wrote:
> > 2016-01-22 23:50 GMT+01:00 Kees Cook <keescook@chromium.org>:
> >
> > > > Seems that Debian and some older Ubuntu versions are already using
> > > >
> > > > $ sysctl -a | grep usern
> > > > kernel.unprivileged_userns_clone = 0
> > > >
> > > > Shall we be consistent wit it?
> > >
> > > Oh! I didn't see that on systems I checked. On which version did you find that?
> >
> > $ uname -a
> > Linux bc1 4.3.0-0.bpo.1-amd64 #1 SMP Debian 4.3.3-5~bpo8+1
> > (2016-01-07) x86_64 GNU/Linux
> > $ cat /etc/debian_version
> > 8.2
>
> Ah-ha, Debian only, though it looks like this was just committed to
> the Ubuntu kernel tree too:
>
>
> > IIRC some older kernels delivered with Ubuntu Precise were also using
> > it (but maybe I'm mistaken)
>
> I don't see it there.
>
> I think my patch is more complete, but I'm happy to change the name if
> this sysctl has already started to enter the global consciousness. ;)
>
> Serge, Ben, what do you think?
I agree that using the '_restrict' suffix for new restrictions makes
sense. I also don't think that a third possible value for
kernel.unprivileged_userns_clone would would be understandable.
I would probably make kernel.unprivileged_userns_clone a wrapper for
kernel.userns_restrict in Debian, then deprecate and eventually remove
it.
Ben.
--
Ben Hutchings
Life is what happens to you while you're busy making other plans.
- John Lennon
