Access control introduction¶

In a default configuration, the libvirtd daemon has three levels of access control. All connections start off in an unauthenticated state, where the only API operations allowed are those required to complete authentication. After successful authentication, a connection either has full, unrestricted access to all libvirt API calls, or is locked down to only "read only" (see 'Anonymous' in the table below) operations, according to what socket a client connection originated on.

The access control framework allows authenticated connections to have fine grained permission rules to be defined by the administrator. Every API call in libvirt has a set of permissions that will be validated against the object being used. For example, the virDomainSetSchedulerParametersFlags method will check whether the client user has the write permission on the domain object instance passed in as a parameter. Further permissions will also be checked if certain flags are set in the API call. In addition to checks on the object passed in to an API call, some methods will filter their results. For example the virConnectListAllDomains method will check the search_domains on the connect object, but will also filter the returned domain objects to only those on which the client user has the getattr permission.

Access control drivers¶

The access control framework is designed as a pluggable system to enable future integration with arbitrary access control technologies. By default, the none driver is used, which does no access control checks at all. At this time, libvirt ships with support for using polkit as a real access control driver. To learn how to use the polkit access driver consult the configuration docs.

The access driver is configured in the libvirtd.conf configuration file, using the access_drivers parameter. This parameter accepts an array of access control driver names. If more than one access driver is requested, then all must succeed in order for access to be granted. To enable 'polkit' as the driver:

# augtool -s set '/files/etc/libvirt/libvirtd.conf/access_drivers[1]' polkit

And to reset back to the default (no-op) driver

# augtool -s rm /files/etc/libvirt/libvirtd.conf/access_drivers

Note: changes to libvirtd.conf require that the libvirtd daemon be restarted.

Objects and permissions¶

Libvirt applies access control to all the main object types in its API. Each object type, in turn, has a set of permissions defined. To determine what permissions are checked for specific API call, consult the API reference manual documentation for the API in question.

connect - virConnectPtr¶

domain - virDomainPtr¶

interface - virInterfacePtr¶

network - virNetworkPtr¶

network-port - virNetworkPortPtr¶

node-device - virNodeDevicePtr¶

nwfilter - virNWFilterPtr¶

nwfilter-binding - virNWFilterBindingPtr¶

secret - virSecretPtr¶

storage-pool - virStoragePoolPtr¶

storage-vol - virStorageVolPtr¶