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

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2024-01-28 00:14:30 +01:00
---
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](https://gitlab.com/apparmor/apparmor/-/wikis/AppArmorInSystemd#early-policy-loads) load **must** also be enabled.
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`:
```diff
- make
+ make full
```
**:material-ubuntu: Ubuntu & :material-debian: Debian**
In `debian/rules`, add the following lines:
```make
override_dh_auto_build:
make full
```
**:simple-suse: OpenSUSE**
In `dists/apparmor.d.spec`, replace `%make_build` by `make full`
```diff
- %make_build
+ make 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`][full]** group.
### Systemd
In addition to systemd services (`systemd-*`) that have their own profiles, systemd itself, is confined using:
- [x] **`systemd`**: For systemd as PID 1, designed such as:
- It allows internal systemd access,
- It allows starting all common root services.
- [ ] **`systemd-user`**: For `systemd --user`, designed such as:
- It allows internal systemd user access,
- It allows starting all common user services.
Both `systemd` and `systemd-user` should not fallback at all. I am working on some new profiles to ensure that 99% of program started by system have a profile.
These profiles are only intended to confine themselves. Any services started by systemd must have their corresponding profile. It means that for a given distribution, the following services must have profiles:
- [x] For `systemd`:
```sh
/usr/lib/systemd/system-generators/*
/usr/lib/systemd/system-environment-generators/*
/usr/lib/systemd/system/*.service
```
- [ ] For `systemd-user`
```sh
/usr/lib/systemd/user-environment-generators/*
/usr/lib/systemd/user-generators/*
/usr/lib/systemd/user/*.service
```
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 fallbacks 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).
[apparmor-wiki]: https://gitlab.com/apparmor/apparmor/-/wikis/FullSystemPolicy
[full]: https://github.com/roddhjav/apparmor.d/blob/main/apparmor.d/groups/_full