Core interfaces reference

Ubuntu Core docs
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This document references all the interfaces available by default on an Ubuntu Core system.

Terminology

  • Auto-connect: the interface is connected upon snap install

  • Transitional: the interface supports traditional desktop features that were not designed with strong application isolation in mind and will be deprecated when a technology more in adequacy with the snap security policy is available.

Interfaces

Interface name Purpose Auto-connect Transitional Attributes
account-control Can add users and change password. Suitable for administration tools. no no
camera Can access the first video camera. Suitable for programs wanting to use webcams. no no
dbus Providing snaps implementing a DBus API may be accessed via their well-known DBus connection name (2.20+). no no name (slot): well-known DBus connection name for the service (eg, org.foo.bar)<br>{=html} bus (slot): DBus bus to use (ie, session or system)<br>{=html} name (plug): well-known DBus connection name of the service from the providing snap<br>{=html} bus (plug): DBus bus to use for providing snap
gsettings Can access global gsettings of the user’s session which gives privileged access to sensitive information stored in gsettings and allows adjusting settings of other applications. yes yes
home Can access non-hidden files in user’s $HOME and gvfs mounted directories owned by the user to read/write/lock. yes on classic (traditional distributions), no otherwise yes
mpris Providing snaps implementing the Media Player Remote Interfacing Specification (mpris) may be accessed via their well-known DBus name. no no name (slot): optional, media player name to use for DBus well-known name
network Can access the network as a client. yes no
network-bind Can access the network as a server. yes no
opengl Can access OpenGL hardware. yes no
optical-drive Can access the first optical drive in read-only mode. Suitable for CD/DVD playback. yes no
password-manager-service Can access global password manager services provided by popular Desktop Environment (eg, Secret Service and KWallets) which gives privileged access to sensitive information stored in the user’s session (2.27+). no yes
pulseaudio Can access the PulseAudio sound server which allows for sound playback in games and media application. Recording not supported but will be in a future release. yes no
removable-media Can access files from removable media in /media and /run/media no no
screen-inhibit-control Can access desktop session manager screen inhibit and uninhibit functionality. yes no
shutdown Can control the system power state and rebooting, powering off or halting the system. no no
unity7 Can access Unity7. Unity 7 runs on X and requires access to various DBus services. This interface grants privileged access to the user’s session since the Unity 7 environment does not prevent eavesdropping or apps interfering with one another. yes yes
wayland Can access compositors supporting the wayland protocol (2.28+). yes no
x11 Can access the X server which gives privileged access to the user’s session since X does not prevent eavesdropping or apps interfering with one another. yes yes
account-control Can create and delete non-system extra users and change the password for non-system extra users (2.22+). no no
alsa Can directly access ALSA devices in /dev/snd. no no
autopilot-introspection Can be introspected by autopilot (2.24+). no no
avahi-control Can access and control snaps providing Avahi mDNS/DNS-SD services on the network which gives privileged access to the service (2.28+). no no
avahi-observe Can access snaps providing Avahi to browse for mDNS/DNS-SD services on the network. no no
bluetooth-control Allow to manage the kernel side Bluetooth stack. no no
bluez Can access snaps providing the bluez interface which gives privileged access to bluetooth. no no
broadcom-asic-control Can access broadcom-asic devices and sysfs interfaces (2.28+). no no
browser-support Can access files and IPC needed by modern browsers. This interface is intended to be used when using an embedded Chromium Content API or using the sandboxes in major browsers from vendors like Google and Mozilla. The allow-sandbox attribute may be used to give the necessary access to use the browser’s sandbox functionality. yes no allow-sandbox: true or false (defaults to false)
classic-support Allows resources necessary for running as classic dimension snap which gives device ownership to the snap. This interface is reserved for the classic snap (2.23). no no
content Can access content from the providing snap from within the consuming snap’s filesystem area. yes for snaps from same publisher, no otherwise no read (slot): read-only paths from providing snap to expose to the consuming snap<br>{=html} write (slot): read-write paths from providing snap to expose to the consuming snap<br>{=html} content (slot): reference to plug side of connection. Defaults to local slot name<br>{=html} default-provider (plug): name preferred providing snap<br>{=html} target (plug): path in consuming snap to find providing snap’s files<br>{=html} content (plug): reference to slot side of connection. Defaults to local plug name
core-support Can control all aspects of systemd via the systemctl command, update rsyslog configuration, update systemd-timesyncd configuration and update/apply sysctl configuration which gives privileged access to the system (2.22+). Reserved for core snaps (type: os). no no
cups-control Can access cups control socket which gives privileged access to configure printing. no no
dcdbas-control Can interact with the Dell Systems Management Base Driver which provides a sysfs interface for systems management software such as Dell OpenManage to perform system management interrupts and host control actions (system power cycle or power off after OS shutdown) on certain Dell systems. no no
docker Can access snaps providing the docker interface which gives privileged access to the system. no no
docker-support Can access resources and syscalls necessary to run Docker application containers. The privileged-containers attribute may be used to give the necessary access to run privileged containers. Providing snaps specifying this interface currently may only be established with the Docker project. no no privileged-containers (plug): true or false (defaults to false)
firewall-control Can configure network firewalling giving privileged access to networking. no no
framebuffer Can use the universal framebuffer (/dev/fb[0-9]*, (2.22+)). no no
fuse-support Can mount fuse filesystems (as root only). no no
fwupd Can access snaps providing the fwupd interface which gives privileged access to update UEFI capsule format firmware. no no
gpio Can access GPIO devices. This is restricted because it provides privileged access to GPIO hardware. no no
greengrass-support Can access resources and syscalls necessary to run Amazon Greengrass services and lambda functions. Providing snaps specifying this interface currently may only be established with the Amazon Greengrass project (2.26+). no no
hardware-observe Can query hardware information from the system. no no
hardware-random-control Allow read/write access to /dev/hwrng (2.25+). no no
hardware-random-observe Allow read access to /dev/hwrng (2.25+). no no
hidraw Can access hidraw devices. This is restricted because it provides privileged access to hardware devices. no no
i2c Can access i2c devices. This is restricted because it provides privileged access to hardware devices. no no
iio Can access IIO devices. This is restricted because it provides privileged access to IIO hardware (2.20+). no no
io-ports-control Can write to /dev/port to change the I/O port permissions and privilege level of the calling process and disable interrupts (2.21+). no no
joystick Can access /dev/js* devices (2.24+). no no
kernel-module-control Can insert kernel modules. This interface gives privileged access to the device. no no
kubernetes-support Can access resources and syscalls necessary to operate as the Kubernetes service and run application containers (2.25+). no no
kvm Can access /dev/kvm which gives privileged access to the kvm hypervisor (2.28+). no no
libvirt Can access the libvirt control socket, which gives privileged access to control libvirtd on the host. This is commonly used to create and manage QEMU/KVM instances on the host. no no
locale-control Can manage locales directly separate from config core. no no
location-control Can access snaps providing the location-control interface which gives privileged access to configure, observe and use location services. no no
location-observe Can access snaps providing the location-observe interface which gives privileged access to query location services. no no
log-observe Can read system logs and set kernel log rate-limiting. no no
lxd Can use the LXD API via the socket provided by the “lxd” snap. LXD_DIR must be set to /var/snap/lxd/common/lxd. This interface requires manual connection. no no
lxd-support Can access all resources and syscalls on the device for LXD to mediate access for its containers. This interface currently may only be established with the upstream LXD project. no yes
maliit Can access snaps providing the maliit input interface (2.24+). no no
media-hub Can access snaps providing the media-hub interface (2.25+). yes no
mir Can access snaps providing the mir display server interface. yes no
modem-manager Can access snaps providing the modem-manager interface which gives privileged access to configure, observe and use modems. no no
mount-observe Can query system mount information. This is restricted because it gives privileged read access to mount arguments and should only be used with trusted apps. no no
netlink-audit Can communicate via NETLINK_AUDIT (2.26+). no no
netlink-connector Can communicate via NETLINK_CONNECTOR (2.26+). no no
network-control Can configure networking and network namespaces via ip netns (2.20+) which gives wide, privileged access to networking. no no
network-manager Can access snaps providing the network-manager interface which gives privileged access to configure and observe networking. no no
network-observe Can query network status information which gives privileged read-only access to networking information. no no
network-setup-control Can read/write network setup configuration files. This is restricted because it gives access to system network configuration which can container network security details (2.22+). no no
network-setup-observe Can read network setup configuration files. This is restricted because it gives access to system network configuration which can contain network security details. no no
network-status Can access snaps providing the NetworkingStatus interface (2.25+). yes no
ofono Can access snaps providing the ofono interface which gives privileged access to configure, observe and use ofono devices. no no
online-accounts-service Can access snaps providing the Online Accounts Service interface (2.25+). yes no
openvswitch Can access the openvswitch control socket, which gives privileged access to control openvswitch on the host (2.20+). no no
openvswitch-support Enables kernel support for openvswitch (2.20+). no no
physical-memory-control Can write to /dev/mem to access architecture-specific subset of the physical address space for common use cases (eg, X without KMS, dosbox, etc) when kernels are compiled with STRICT_DEVMEM=y (required for certified kernels). With STRICT_DEVMEM=n, can write to all physical memory (2.21+). no no
physical-memory-observe Can read from /dev/mem to access architecture-specific subset of the physical address space for common use cases (eg, X without KMS, dosbox, etc) when kernels are compiled with STRICT_DEVMEM=y (required for certified kernels). With STRICT_DEVMEM=n, can read from all physical memory (2.21+). no no
ppp Can access Point-to-Point protocol daemon which gives privileged access to configure and observe PPP networking. no no
process-control Can manage processes via signals and nice. no no
raw-usb Can directly access connected USB devices via a raw interface (2.18+). no no
serial-port Can access serial ports. This is restricted because it provides privileged access to configure serial port hardware. Note that the slot is meant to be implemented by a gadget snap (this is not provided by the core snap). no no
snapd-control Can manage snaps via snapd. no no
spi Can access SPI devices. This is restricted because it provides privileged access to SPI hardware (2.28+). no no
storage-framework-service Can access snaps providing the Storage Framework Service interface (2.25+). no no
system-observe Can query system status information which gives privileged read access to all processes on the system. no no
system-trace Can use kernel tracing facilities. This is restricted because it gives privileged access to all processes on the system and should only be used with trusted apps. no no
thumbnailer-service Can access snaps providing the thumbnailer service interface (2.22+). no no
time-control Can set system time and date and query systemd-timedated for time information. no no
timeserver-control Can manage timeservers via systemd-timedated and directly separate from config core no no
timezone-control Can manage timezone via systemd-timedated and directly separate from config core no no
tpm Can access the tpm device /dev/tpm0. no no
ubuntu-download-manager Can access snaps providing the ubuntu-download-manager interface. yes no
udisks2 Can access snaps providing the udisks2 interface which gives privileged access to storage on the device no no
uhid Can access /dev/uhid to create kernel hid devices from user-space which gives privileged access to HID transport drivers. no no
unity8 Can access Unity8 (2.22+). This interface is in active development and should not yet be used in production and its use is therefore restricted. yes no
unity8-calendar Can access snaps providing the Unity8 calendar interface which gives access to the Unity8 global calendar. no no
unity8-contacts Can access snaps providing the Unity8 contacts interface which gives access to the Unity8 global contacts list. no no
upower-observe Can access snaps providing the UPower interface for power devices, history and statistics. yes no