Re: [Qemu-devel] [RFC PATCH] virtio-9p: Use clone approach to fix TOCTOU vulnerability

["M. Mohan Kumar" <mohan@in.ibm.com>]

On Wed, Jun 15, 2011 at 04:24:12PM +0100, Stefan Hajnoczi wrote:
> On Tue, Jun 14, 2011 at 9:12 AM, M. Mohan Kumar <mohan@in.ibm.com> wrote:
> > [RFC PATCH] virtio-9p: Use clone approach to fix TOCTOU vulnerability
> >
> > In passthrough security model, following a symbolic link in the server
> > side could result in TOCTTOU vulnerability.
> >
> > Use clone system call to create a thread which runs in chrooted
> > environment. All passthrough model file operations are done from this
> > thread to avoid TOCTTOU vulnerability.
> >
> > Signed-off-by: Venkateswararao Jujjuri <jvrao@linux.vnet.ibm.com>
> > Signed-off-by: M. Mohan Kumar <mohan@in.ibm.com>
> > ---
> >  fsdev/file-op-9p.h         |    1 +
> >  hw/9pfs/virtio-9p-coth.c   |  105 +++++++++++++++++++++++++++++++++++++++++--
> >  hw/9pfs/virtio-9p-coth.h   |   13 +++++-
> >  hw/9pfs/virtio-9p-device.c |    7 +++-
> >  hw/9pfs/virtio-9p.h        |    6 ++-
> >  5 files changed, 124 insertions(+), 8 deletions(-)
> 
> This patch isn't against upstream virtio-9p.  Please post a link to a
> repo or more information.

Hi Stefan,
Thanks for the detailed review. I will address review comments in next
version.