[libvirt] [PATCH] virt-aa-helper: disallow VNC socket read permissions

[Cedric Bosdonnat]

On Fri, 2016-04-08 at 18:55 +0200, Guido Günther wrote:
> On Fri, Apr 08, 2016 at 09:01:33AM -0400, Cole Robinson wrote:
> > From: Simon Arlott <bugzilla.redhat.simon at arlott.org>
> > 
> > The VM does not need read permission for its own VNC socket to
> > create(),
> > bind(), accept() connections or to receive(), send(), etc. on
> > connections.
> > 
> > https://bugzilla.redhat.com/show_bug.cgi?id=1312573
> > ---
> >  src/security/virt-aa-helper.c | 2 +-
> >  1 file changed, 1 insertion(+), 1 deletion(-)
> > 
> > diff --git a/src/security/virt-aa-helper.c b/src/security/virt-aa
> > -helper.c
> > index 50d2a08..a4cb409 100644
> > --- a/src/security/virt-aa-helper.c
> > +++ b/src/security/virt-aa-helper.c
> > @@ -1062,7 +1062,7 @@ get_files(vahControl * ctl)
> >      for (i = 0; i < ctl->def->ngraphics; i++) {
> >          if (ctl->def->graphics[i]->type ==
> > VIR_DOMAIN_GRAPHICS_TYPE_VNC &&
> >              ctl->def->graphics[i]->data.vnc.socket &&
> > -            vah_add_file(&buf, ctl->def->graphics[i]
> > ->data.vnc.socket, "rw"))
> > +            vah_add_file(&buf, ctl->def->graphics[i]
> > ->data.vnc.socket, "w"))
> >              goto cleanup;
> >      }
> 
> ACK. I'd be great if Jamie or Cedric would comment also though on
> this
> security sensitive stuff.

I'm not a socket expert, but it sounds weird to me that recv doesn't
need read access to the socket file. ACK to this patch as long a read
is really not needed.

Jamie, any thoughts?

--
Cedric