[libvirt PATCH] remote: use SocketMode=0600 when polkit is not compiled

[Jiri Denemark]

On Wed, Sep 02, 2020 at 18:54:36 +0100, Daniel P. Berrangé wrote:
> The systemd .socket unit files we ship for libvirt daemons use
> SocketMode=0666 on the assumption that libvirt is built with
> polkit which provides access control.
> 
> Some people, however, may have explicitly turned off polkit at
> build time and not realize that leaves them insecure unless
> they also change the SocketMode.  This addresses that problem
> by making the SocketMode default to 0600 when polkit is
> disabled at compile time.
> 
> Note we cannot automatically fix the case where the user
> compiles polkit, but then overrides the libvirtd.conf defaults
> to disable polkit. This is what lead to CVE-2020-15708 in
> Ubuntu 20.10.  We can at least improve the inline comments
> in the config file to give a clearer warning though, which
> may have helped avoid the mistaken config.
> 
> Signed-off-by: Daniel P. Berrangé <berrange at redhat.com>
> ---
>  src/meson.build               | 11 ++++++++++
>  src/remote/libvirtd.conf.in   | 40 ++++++++++++++++++++++++++---------
>  src/remote/libvirtd.socket.in |  2 +-
>  3 files changed, 42 insertions(+), 11 deletions(-)

Reviewed-by: Jiri Denemark <jdenemar at redhat.com>