apparmor.d/docs/full-system-policy.md

title
Full system policy

!!! danger

Full system policy is still under early development:

- Do not run it outside a development VM! 
- This is an **advanced** feature, you should understand what you are doing

**You have been warned!!!**

!!! quote

AppArmor is also capable of being used for full system policy where processes are by default not running under the `unconfined` profile. This might be useful for high security environments or embedded systems.

*Source: [AppArmor Wiki][apparmor-wiki]*

Install

This feature is only enabled when the project is built with make full. Early policy load must also be enabled. Once apparmor.d has been installed in FSP mode, it is required to reboot to apply the changes.

In /etc/apparmor/parser.conf ensure you have:

write-cache
cache-loc /etc/apparmor/earlypolicy/
Optimize=compress-fast

:material-arch: Archlinux

In PKGBUILD, replace make by make full:

-  make
+  make full

:material-ubuntu: Ubuntu & :material-debian: Debian

In debian/rules, add the following lines:

override_dh_auto_build:
	make full

:simple-suse: OpenSUSE

In dists/apparmor.d.spec, replace %make_build by make full

-  %make_build
+  %make_build full

Partial install

Use the make full command to build instead of make

Structure

The profiles dedicated for full system policies are maintained in the _full group.

Systemd

systemd

This profile aims to confine PID 1. Systemd is (kind of obviously) a highly privileged program. The purpose of this profile is to transition to other less privileged program as soon as possible. On high security environments, it can also be used to strictly limit the list of allowed privileged program.

• It allows internal systemd access,
• It allows starting all common root services.

To work as intended, all privileged services started by systemd must have a profile. For a given distribution, the list of these services can be found under:

/usr/lib/systemd/system-generators/*
/usr/lib/systemd/system-environment-generators/*
/usr/lib/systemd/system/*.service

The main fallback profile (default) is not intended to be used by privileged program or service. Such programs must have they dedicated profile and will fail otherwise. This is a feature, not a bug.

systemd-user

This profile is for systemd --user, it aims to confine userland systemd. It does not require a lot of access and is only intended to handle user services.

• It allows internal systemd user access,
• It allows starting all common user services.

To work as intended, userland services started by systemd --user should have a profile. For a given distribution, the list of these services can be found under:

/usr/lib/systemd/user-environment-generators/*
/usr/lib/systemd/user-generators/*
/usr/lib/systemd/user/*.service

!!! info

To be allowed to run, additional root or user services may need to add extra rules inside the `usr/systemd.d` or `usr/systemd-user.d` directory. For example, when installing a new privileged service `foo` with [stacking](#no-new-privileges) you may need to add the following to `/etc/apparmor.d/usr/systemd.d/foo`:
```
@{lib}/foo rPx -> systemd//&foo,
```

Fallback

In addition to the systemd profiles, a full system policy needs to ensure that no program run in an unconfined state at any time. The fallback profiles consist of a set generic specialized profiles:

• default is used for any classic user application with a GUI. It has full access to user home directories.
• bwrap, bwrap-app are used for classic user application that are sandboxed with bwrap.

!!! warning

The main fallback profile (`default`) is not intended to be used by priviligied program or service. Such programs **must** have they dedicaded profile and would break otherwise.

Additionally, special user access can be setup using PAM rules set such as a random shell interactively opened (as user or as root).