On 27/01/16 08:20 -0430, Flavio Percoco wrote:
On 26/01/16 09:11 +0000, Daniel P. Berrange wrote:
On Sun, Jan 24, 2016 at 12:00:16AM +0200, Duncan Thomas wrote:
I guess my wisdom would be 'why'? What does this enable you to do that you
couldn't do with similar ease with the formats we have and are people
trying to do that frequently.

We've seen in cinder that image formats have a definite security surface to
them, and with glance adding arbitrary conversion pipelines, that surface
is going to increase with every format we add. This should mean we tend
towards being increasingly conservative I think.

Safely extracting tar file contents to create a disk image to run the VM
from is particularly non-trivial. There have been many security flaws in
the past with apps doing tar file unpacking in this kind of scenario. For
example, Docker has had not one, but *three* vulnerabilities in this area
CVE-2014-6407, CVE-2014-9356, and CVE-2014-9357. So unless there is a
pretty compelling reason, I'd suggest we stay away from supporting tar
as an image format, and require traditional image formats where we we can
treat the file payload as an opaque blob and thus avoid all these file
processing risks.

++

From a Glance perspective, there wouldn't be much to do and most of the security
issues would live in the Ironic side. However, as a community, I think we should
send a clear message and protect our users and, in this case, the best way is to
avoid adding this format as supported.

In future works (image conversions and whatnot) this could impact Glance as 
well.

It was brought to my attention (thanks Erno) that we support OVA already. This
means we're basically exposed to the above already as the OVA container is a
tarball anyway.

Glance protects itself from this by either not doing anything to the image or
isolating operations on the image to specific workers (of course, this goes in
addition to other security measures).

The difference, though, is that OVA files are a known container format for
images, whereas tar.gz isn't.

Flavio

Cheers,
Flavio

Regards,
Daniel
--
|: http://berrange.com      -o-    http://www.flickr.com/photos/dberrange/ :|
|: http://libvirt.org              -o-             http://virt-manager.org :|
|: http://autobuild.org       -o-         http://search.cpan.org/~danberr/ :|
|: http://entangle-photo.org       -o-       http://live.gnome.org/gtk-vnc :|

__________________________________________________________________________
OpenStack Development Mailing List (not for usage questions)
Unsubscribe: openstack-dev-requ...@lists.openstack.org?subject:unsubscribe
http://lists.openstack.org/cgi-bin/mailman/listinfo/openstack-dev

--
@flaper87
Flavio Percoco



__________________________________________________________________________
OpenStack Development Mailing List (not for usage questions)
Unsubscribe: openstack-dev-requ...@lists.openstack.org?subject:unsubscribe
http://lists.openstack.org/cgi-bin/mailman/listinfo/openstack-dev


--
@flaper87
Flavio Percoco

Attachment: signature.asc
Description: PGP signature

__________________________________________________________________________
OpenStack Development Mailing List (not for usage questions)
Unsubscribe: openstack-dev-requ...@lists.openstack.org?subject:unsubscribe
http://lists.openstack.org/cgi-bin/mailman/listinfo/openstack-dev

Reply via email to