Re: LXC: CVE-2017-5985: lxc-user-nic didn't verify network namespace ownership

[Tyler Hicks <tyhicks () canonical com>]

On 03/10/2017 06:03 AM, Stiepan wrote:
> I don't know whether that is the same bug, or a related one, but on Debian8 using LXC from jessie-backports, setting 
> the default route in a container affects the host - namely, from an unpriv. container, setting the route sets the 
> host's route as well.
> lxc-info --version outputs 2.0.6 and no update is currently available (on Debian).

Thanks for the report. I just tried to reproduce the issue on Ubuntu
16.04 with 2.0.7-0ubuntu1~16.04.2, which is the package patched for the
issue that I announced in this thread. I couldn't reproduce it.

I then installed an old 2.0.6 based deb (2.0.6-0ubuntu1~ubuntu16.04.1)
and still couldn't reproduce it.

I'd suggest opening an upstream bug here:

  https://github.com/lxc/lxc/issues/new

(Normally, they prefer private security bugs on Launchpad but your
report to this list is already public so I don't see a need.)

Tyler

> Stiepan
>
>
>
> -------- Original Message --------
> Subject: [oss-security] LXC: CVE-2017-5985: lxc-user-nic didn't verify network namespace ownership
> Local Time: 9 March 2017 5:54 PM
> UTC Time: 9 March 2017 16:55
> From: tyhicks () canonical com
> To: oss-security () lists openwall com
> Stéphane Graber <stgraber () ubuntu com>
>
> Jann Horn discovered that the lxc-user-nic program could be tricked into
> operating on a network namespace over which the caller did not hold
> privilege.
>
> The behavior didn't follow what was documented in the lxc-user-nic(1)
> man page:
>
> It ensures that the calling user is privileged over the network
> namespace to which the interface will be attached.
>
> This issue is CVE-2017-5985.
>
> https://lists.linuxcontainers.org/pipermail/lxc-users/2017-March/012925.html
> https://launchpad.net/bugs/1654676
> https://github.com/lxc/lxc/commit/16af238036a5464ae8f2420ed3af214f0de875f9
>
> Tyler

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