apparmor.d/docs/development/abstractions.md

title
Abstractions

This project and the apparmor profile official project provide a large selection of abstractions to be included in profiles. They should always be used as they target wide compatibility across hardware and distribution wile only allowing the bare minimum access.

!!! example

For instance, to allow download directory access, instead of writing:
```sh
owner @{HOME}/@{XDG_DOWNLOAD_DIR}/{,**} rw,
```

You should write:
```sh
include <abstractions/user-download-strict>
```

All of these abstractions can be extended by a system admin by adding rules in a file under /etc/apparmor.d/<name>.d where <name> is the name of one of these abstractions.

Application helper

Abstraction that aim at including a complete set of rule for a given program. The calling profile only need to add rules dependant of its use case/program.

It is mostly useful for program often used in sub profile or for forks based on the same upstream.

app/chromium

Full set of rules for all chromium based browsers. It works as a function and requires some variables to be provided as arguments and set in the header of the calling profile:

!!! note ""

[apparmor.d/groups/browsers/chromium](https://github.com/roddhjav/apparmor.d/blob/e979fe05b06f525e5a65c767b4eabe5600147355/apparmor.d/groups/browsers/chromium#L10-L14)
``` sh linenums="10"
@{name} = chromium
@{domain} = org.chromium.Chromium
@{lib_dirs} = @{lib}/@{name}
@{config_dirs} = @{user_config_dirs}/@{name}
@{cache_dirs} = @{user_cache_dirs}/@{name}
```

If your application requires chromium to run use common/chromium or common/electron instead.

app/pgrep

app/sudo

Minimal set of rules for profile including internal sudo. Interactive sudo need more rules. It is intended to be used in profile or sub profile that need to elevate their privileges using sudo or su for a very specific action:

  @{bin}/sudo rCx  -> root,

  profile root {
    include <abstractions/base>
    include <abstractions/app/sudo>

    include if exists <local/<profile_name>_root>
  }

app/systemctl

Alternative solution for child-systemctl, when the child profile provide too much/not enough access. This abstraction should be used by a sub profile as follows:

  @{bin}/systemctl  rCx ->  systemctl,

  profile systemctl {
    include <abstractions/base>
    include <abstractions/app/systemctl>

    include if exists <local/<profile_name>_systemctl>
  }

Common Dependencies

On the contrary of abstractions/app/, abstractions in this directory are expected to provide a minimal set of rules to make a program using a dependency work.

common/app

Common rules for unknown userland UI applications sandboxed using bwrap.

!!! warning

This abstraction is wide on purpose. It is meant to be used by sandboxed applications that have no way to restrict access depending on the application being confined.

**Do not use it for classic profile.**

common/apt

Minimal access to apt sources, preferences and configuration.

common/bwrap

Minimal set of rules for sandboxed program using bwrap. A profile using this abstraction still needs to set:

• The flag: attach_disconnected
• Bwrap execution: @{bin}/bwrap rix,

common/chromium

Minimal set of rules for chromium based application. Handle access for internal sandbox.

common/electron

Minimal set of rules for all electron based UI application. It works as a function and requires some variables to be provided as arguments and set in the header of the calling profile:

!!! note ""

[apparmor.d/profile-s-z/spotify](https://github.com/roddhjav/apparmor.d/blob/e979fe05b06f525e5a65c767b4eabe5600147355/apparmor.d/profile-s-z/spotify#L10-L13)
``` sh linenums="10"
@{name} = spotify
@{lib_dirs} = /opt/@{name}
@{config_dirs} = @{user_config_dirs}/@{name}
@{cache_dirs} = @{user_cache_dirs}/@{name}
```

common/systemd

Common set of rules for internal systemd suite.

!!! warning

It should **only** be used by the systemd suite.

Audio

audio-client

Most programs do not need access to audio devices, audio-client only includes configuration files to be used by client applications.

audio-server

Provide access to audio devices. It should only be used by audio servers that need direct access to them.

Dbus

See the Dbus page.

User files

user-read

This abstraction gives read access on all defined user directories. It should only be used if access to ALL folders under xdg directories is required.

user-download-strict

Provide write access to all user download directories

deny-sensitive-home

Deny access to some sensitive directories under /home/. It is intended to be used by the few profiles that legitimately require full unrestricted access over all user directories (file browser and search engines). It allows to us to block access to really sensitive data to such profiles.

!!! danger

**Do not use this abstraction for other profile without explicit authorisation from the project maintainer**

Per the **[Rule :material-numeric-1-circle:](index.md#rule-mandatory-access-control)** of this project:

> Only what is explicitly required should be authorized. Meaning, you should **not** allow everything (or a large area) and deny some sub areas.

dconf-write

Permissions for querying dconf settings with write access.

Shell

!!! warning

These abstractions are only required when an interactive shell is started. Classic shell scripts do not need them.

Only use shells, other abstractions are software dependant and should not usually be used directly.

shells

Common rules for interactive shells.

bash-strict

Common rules for interactive shell using bash.

zsh

Common rules for interactive shell using zsh.

System

nameservice-strict

Many programs wish to perform nameservice like operations, such as looking up users by name or Id, groups by name or Id, hosts by name or IP, etc.

Use this abstraction instead of upstream abstractions/nameservice as upstream abstraction also provide full network access which is not needed for a lot of programs.

app-open

Instead of allowing the run of all software under @{bin} or @{lib} the purpose of this abstraction is to list all GUI program that can open resources. Ultimately, only sandbox manager program such as bwrap, snap, flatpak, firejail should be present here. Until this day, this profile will be a controlled mess.

Devices

devices-usb

Provide access to USB devices

disks-write

Provide read write access to disks devices

disks-read

Provide read only access to disks devices

Desktop Environment

desktop

Unified minimal abstraction for all UI application regardless of the desktop environment. When supported in apparmor, condition will be used in this abstraction to filter resources specific for supported DE.

It is safe to use it in GUI application. As well as minimal desktop resource files, it includes access to configuration for: fonts, gtk & qt, wayland & xorg.

gnome-strict

Same than abstractions/desktop but limited to gnome.

kde-strict

Same than abstractions/desktop but limited to KDE.

Graphics

Use either graphics or graphics-full. The other abstractions are hardware/software dependant and should not usually be used directly.

graphics

Unified abstraction for GPU access regardless of the hardware used.

Replace and highly restrict <abstractions/opencl>

graphics-full

Identical to graphics with more direct access to nvidia GPU devices.

dri

Linux's graphics stack which allows unprivileged user-space programs to issue commands to graphics hardware without conflicting with other programs. Mostly used by Intel (integrated or not) and AMD GPU.

Modernized equivalent of both dri-common and dri-enumerate

nvidia-strict

Modernized equivalent of abstractions/nvidia

vulkan-strict

Modernized equivalent of abstractions/vulkan