Client access control

Libvirt's client access control framework allows administrators to setup fine grained permission rules across client users, managed objects and API operations. This allows client connections to be locked down to a minimal set of privileges.

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" 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.

virConnectPtr

Permission Description
detect-storage-pools Detect storage pools
getattr Access connection
interface-transaction Interface transactions
pm-control Use host power management
read Read host
search-domains List domains
search-interfaces List interfaces
search-networks List networks
search-node-devices List node devices
search-nwfilters List network filters
search-secrets List secrets
search-storage-pools List storage pools
write Write host

virDomainPtr

Permission Description
block-read Read domain block
block-write Write domain block
core-dump Dump domain
delete Delete domain
fs-freeze Freeze and thaw domain filesystems
fs-trim Trim domain filesystems
getattr Access domain
hibernate Hibernate domain
init-control Domain init control
inject-nmi Inject domain NMI
mem-read Read domain memory
migrate Migrate domain
open-device Open domain device
open-graphics Open domain graphics
open-namespace Open domain namespace
pm-control Use domain power management
read Read domain
read-secure Read secure domain
reset Reset domain
save Save domain
screenshot Take domain screenshot
send-input Send domain input
send-signal Send domain signal
set-password Set password of the domain's account
set-time Write domain time
snapshot Snapshot domain
start Start domain
stop Stop domain
suspend Suspend domain
write Write domain

virInterfacePtr

Permission Description
delete Delete interface
getattr Access interface
read Read interface
save Save interface
start Start interface
stop Stop interface
write Write interface

virNetworkPtr

Permission Description
delete Delete network
getattr Access network
read Read network
save Save network
start Start network
stop Stop network
write Write network

virNodeDevicePtr

Permission Description
detach Detach node device
getattr Access node device
read Read node device
start Start node device
stop Stop node device
write Write node device

virNWFilterPtr

Permission Description
delete Delete network filter
getattr Access network filter
read Read network filter
save Save network filter
write Write network filter

virSecretPtr

Permission Description
delete Delete secret
getattr Access secret
read Read secret
read-secure Read secure secret
save Save secret
write Write secret

virStoragePoolPtr

Permission Description
delete Delete storage pool
format Format storage pool
getattr Access storage pool
read Read storage pool
refresh Refresh storage pool
save Save storage pool
search-storage-vols List storage pool volumes
start Start storage pool
stop Stop storage pool
write Write storage pool

virStorageVolPtr

Permission Description
create Create storage volume
data-read Read storage volume data
data-write Write storage volume data
delete Delete storage volume
format Format storage volume
getattr Access storage volume
read Read storage volume
resize Resize storage volume