Re: [libvirt] Fine grained Access Control in libVirt

After some background research it doesn't look like anyone have taken on the task yet to add fine-grained access control to libVirt (only option right now is R/W or RO mode). Desired is an addition to libVirt that enables access control on individual actions and data that can be accessed through the library API. This could take the form of an AC-module that, based on the identity of the caller, checks each call and grants/denies access to carry out the action (could also take parameters in account) and optionally filter the return data. The AC-module could then interface different backend AC solutions (SELinux, RBAC, ...) or alternatively implement an internal scheme. When looking at the libvirt core and driver framework it seems promising to inject these kind of call-out hooks either in libvirt.c or between libvirt.c and the underlying drivers, by doing this AC will be enforced independent of if a local or remote call is done to libVirt. I propose an approach to create an AC-module that conforms to the driver API in libVirt and to inject it in the call-path between libvirt.c and the driver(s) to enable the AC-module to inspect the call before sending it to the real driver. Normal call path: user -> libvirt.c -> driver_x AC-module injected in call path: user -> libvirt.c -> AC-module -> driver_x By doing this it can be loaded/unloaded in run-time and also selectable what driver paths it should enforce (hypervisor(aka. driver), storage, network...). The AC-module can also be made in different flavors for different AC backend (SELinux, RBAC, internal, ...) solutions and the appropriate AC-module could be loaded without needing re-compiling. This approach would also leave a very small footprint in existing libvirt code (only need to inject AC-module driver after normal drivers has been loaded)