Re: [Libguestfs] [PATCH] libvirt: disallow non-local connections (RHBZ#1347830)
On Wed, Jun 28, 2017 at 10:33:48AM +0200, Pino Toscano wrote:
On Tuesday, 27 June 2017 22:56:25 CEST Richard W.M. Jones wrote:
>
> Not that I'm opposed to this patch, but there's a bit of history here:
>
> https://www.redhat.com/archives/libguestfs/2012-December/msg00120.html
Hm it doesn't say much more about that though, and the solution I
implemented is even less strict than what Dan suggested back then.
> I think it would be good for libvirt to address the "is remote" issue,
> which libvirt is (in theory) in the best place to address, eg by
> comparing systemd /etc/machine-id on both systems.
I took the approach from what virt-manager does, i.e. consider local
connections whose URI has an empty hostname.
Right, but ::1 and 127.0.0.1 etc are non-empty hostnames which refer
to the local machine. I really think if we're going to add a check we
should add a correct check, and the only way to do this properly is in
libvirt.
OTOH, currently in libvirt there is still no reliable way to detect
whether some connection is local: the internal calculation of the UUID
for the capabilities may use files and tools which can be read and run
by root only, so the output on the same host changes depending on the
user.
Can't we get libvirt to export the machine ID in capabilities?
There is already a //host/uuid field, but as you point out it
is different for different users (WTF?)
> Then we could use that to deny remote URIs, but probably we
wouldn't
> want to deny it completely, but allow a way for callers to bypass the
> check if they know better.
That could be a good idea, how would you expect this bypass to look
like?
I'm not sure. An extra parameter passed in .query_raw I suppose.
Rich.
--
Richard Jones, Virtualization Group, Red Hat http://people.redhat.com/~rjones
Read my programming and virtualization blog: http://rwmj.wordpress.com
libguestfs lets you edit virtual machines. Supports shell scripting,
bindings from many languages. http://libguestfs.org