Re: CVE Request: ro bind mount bypass using user namespaces

[Andy Lutomirski <luto () amacapital net>]

On Tue, Aug 12, 2014 at 10:04 PM, Andy Lutomirski <luto () amacapital net> wrote:
> On Tue, Aug 12, 2014 at 4:54 PM, Andy Lutomirski <luto () amacapital net> wrote:
> > On 08/12/2014 02:48 PM, Kenton Varda wrote:
> > > Due to a bug in the Linux kernel's implementation of remount, on systems
> > > with unprivileged user namespaces enabled, it is possible for an
> > > unprivileged user to gain write access to any visible read-only bind mount.
> > > It is also possible to bypass flags like nodev, nosuid, and noexec.

...

> Yup.  I have a fairly reliable exploit now.  Will post the code in a
> couple of weeks.

To clarify: my exploit has nothing to do with sandboxing.  It roots
default-ish configurations of Fedora 20 and Ubuntu 14.04.

--Andy