Re: [PATCH v3 0/7] User namespace mount updates

[Octavian Purdila <octavian.purdila@intel.com>]

On Tue, Nov 17, 2015 at 9:21 PM, Seth Forshee
<seth.forshee@canonical.com> wrote:
>
> On Tue, Nov 17, 2015 at 08:12:31PM +0100, Richard Weinberger wrote:
> > On Tue, Nov 17, 2015 at 7:34 PM, Seth Forshee
> > <seth.forshee@canonical.com> wrote:
> > > On Tue, Nov 17, 2015 at 05:55:06PM +0000, Al Viro wrote:
> > >> On Tue, Nov 17, 2015 at 11:25:51AM -0600, Seth Forshee wrote:
> > >>
> > >> > Shortly after that I plan to follow with support for ext4. I've been
> > >> > fuzzing ext4 for a while now and it has held up well, and I'm currently
> > >> > working on hand-crafted attacks. Ted has commented privately (to others,
> > >> > not to me personally) that he will fix bugs for such attacks, though I
> > >> > haven't seen any public comments to that effect.
> > >>
> > >> _Static_ attacks, or change-image-under-mounted-fs attacks?
> > >
> > > Right now only static attacks, change-image-under-mounted-fs attacks
> > > will be next.
> >
> > Do we *really* need to enable unprivileged mounting of kernel filesystems?
> > What about just enabling fuse and implement ext4 and friends as fuse
> > filesystems?
> > Using the approaching Linux Kernel Libary[1] this is easy.
>
> I haven't looked at this project, but I'm guessing that programs must be
> written specifically to make use of it? I.e. you can't just use the
> mount syscall, and thus all existing software still doesn't work?
>

The projects includes a lklfuse program that uses fuse to mount a
fileystem image.