ISTM that adding the libvirt-dbus user into the libvirt group is the right fix here. According to /usr/share/dbus-1/system.d/org.libvirt.conf only root and libvirt group users can call its interface. So that useradd seems correct to me, and it should be put into the Debian package.
Unfortunately libvirt-dbus does not use systemd to manage its service, otherwise it could use DynamicUser= and SupplementaryGroups=libvirt.
ISTM that adding the libvirt-dbus user into the libvirt group is the right fix here. According to /usr/share/ dbus-1/ system. d/org.libvirt. conf only root and libvirt group users can call its interface. So that useradd seems correct to me, and it should be put into the Debian package.
Unfortunately libvirt-dbus does not use systemd to manage its service, otherwise it could use DynamicUser= and SupplementaryGr oups=libvirt.