8.4 KiB
| title |
|---|
| Internal |
Profile Context
These are context helper to be used for in sub profile, they aim at providing a minimal set of rules for a given program. The calling profile only needs to add rules dependant of its use case.
See abstractions/app for more information.
Open Resources
The standard way to allow opening resources such as URL, pictures, video, in this project is to use one of the child-open profile available in the children group.
Example:
@{open_path} rPx -> child-open,
Manual
Directly using any of the following:
@{bin}/* PUx,include <abstractions/app-launcher-user>include <abstractions/app-launcher-root>
Allow every installed program to be started from the current program with or without profile. This is a very permissive rule and should be avoided if possible. They are however legitimately needed for program launcher.
child-open
Instead of allowing the ability to run all software in @{bin}/, the purpose of this profile is to list all GUI programs that can open resources. Ultimately, only sandbox manager programs such as bwrap, snap, flatpak, firejail should be present here. Until this day, this profile will be a controlled mess.
??? quote "children/child-open"
``` aa
# Sandbox managers
@{bin}/bwrap rPUx,
@{bin}/firejail rPUx,
@{bin}/flatpak rPx,
@{bin}/snap rPx,
# Labelled programs
@{archive_viewers_path} rPUx,
@{browsers_path} rPx,
@{document_viewers_path} rPUx,
@{emails_path} rPUx,
@{file_explorers_path} rPx,
@{help_path} rPx,
@{image_viewers_path} rPUx,
@{offices_path} rPUx,
@{text_editors_path} rPUx,
# Others
@{bin}/blueman-tray rPx,
@{bin}/discord{,-ptb} rPx,
@{bin}/draw.io rPUx,
@{bin}/dropbox rPx,
@{bin}/element-desktop rPx,
@{bin}/extension-manager rPx,
@{bin}/filezilla rPx,
@{bin}/flameshot rPx,
@{bin}/gimp* rPUx,
@{bin}/gnome-calculator rPUx,
@{bin}/gnome-disk-image-mounter rPx,
@{bin}/gnome-disks rPx,
@{bin}/gnome-software rPx,
@{bin}/gwenview rPUx,
@{bin}/kgx rPx,
@{bin}/qbittorrent rPx,
@{bin}/qpdfview rPx,
@{bin}/smplayer rPx,
@{bin}/steam-runtime rPUx,
@{bin}/telegram-desktop rPx,
@{bin}/transmission-gtk rPx,
@{bin}/viewnior rPUx,
@{bin}/vlc rPUx,
@{bin}/xbrlapi rPx,
# Backup
@{lib}/deja-dup/deja-dup-monitor rPx,
```
child-open-browsers
This version of child-open only allow to open browsers.
??? quote "children/child-open-browsers"
``` aa
@{browsers_path} rPx,
```
child-open-help
This version of child-open only allow to open browsers and help programs.
??? quote "children/child-open-help"
``` aa
@{browsers_path} rPx,
@{help_path} rPx,
```
child-open-strict
This version of child-open only allow to open browsers & folders:
??? quote "children/child-open-strict"
``` aa
@{browsers_path} Px,
@{file_explorers_path} Px,
```
!!! warning
Although needed to not break a program, wrongly used these profiles can lead to confinment escape.
Children profiles
Usually, a child profile is in the children group. They have the following note:
!!! quote
Note: This profile does not specify an attachment path because it is intended to be used only via `"Px -> child-open"` exec transitions from other profiles.
child-modprove-nvidia
Used internally by the nvidia abstraction.
child-pager
Simple access to pagers such as pager, less and more. This profile assumes the pager is reading its data from stdin, not from a file on disk. Supported pagers are: sensible-pager, pager, less, and more.
It can be as follows in a profile:
@{pager_path} rPx -> child-pager,
child-systemctl
Common systemctl action. Do not use it too much as most of the time you will need more privilege than what this profile is giving you.
It is recommended to transition in a subprofile everything that is not generic and that may require some access (so restart, enable...), while child-systemctl can handle the more basic tasks.
Labelled programs
All common programs are tracked and labelled in the apparmor.d/tunables/multiarch.d/programs and
apparmor.d/tunables/multiarch.d/paths files. They can be used in a child-open profile or directly in a profile. They are useful to allow opening resources using a kind of program (browsers, image viewer, text editor...), instead of allowing a given program path.
User Confinement :material-police-badge-outline:{ .pg-red }
!!! warning "TODO"
No New Privileges
No New Privileges is a flag preventing a newly started program to get more privileges than its parent process. This is a good thing for security. And it is commonly used in systemd unit files (when possible). This flag also prevents transitions to other profiles because it could be less restrictive than the parent profile (no Px or Ux allowed).
The possible solutions are:
- The easiest (and unfortunately less secure) workaround is to ensure the programs do not run with no new privileges flag by disabling
NoNewPrivilegesin the systemd unit (or any other options implying it). - Inherit the current confinement (
ix) - Stacking
Stacking
Stacking of two or more profile is the strict intersection them. It is a way to ensure that a profile never becomes more permissive than the intersection of all profiles in the stack. It provides several abilities to the policy author:
- It can be used to ensure that confinement never becomes more permissive.
- To reduce the permissions of a generic profile on a specific task.
- To provide both system level and container and user level policy (when combined with policy namespaces).
!!! note ""
[apparmor.d/groups/browsers/chromium](https://github.com/roddhjav/apparmor.d/blob/b51576139b3ed3125aaa3ea4d737a77baac0f00e/apparmor.d/groups/browsers/chromium#L25)
``` aa linenums="23"
profile chromium @{exec_path} {
...
@{lib_dirs}/chrome_crashpad_handler rPx -> chromium//&chromium-crashpad-handler,
...
}
```
Udev rules
See the kernel docs to check the major block and char numbers used in /run/udev/data/.
Special care must be given as sometimes udev numbers are allocated dynamically by the kernel. Therefore, the full range must be allowed:
!!! note ""
[apparmor.d/groups/virt/libvirtd](https://github.com/roddhjav/apparmor.d/blob/b2af7a631a2b8aca7d6bdc8f7ff4fdd5ec94220e/apparmor.d/groups/virt/libvirtd#L188)
``` aa linenums="179"
@{run}/udev/data/c@{dynamic}:@{int} r, # For dynamic assignment range 234 to 254, 384 to 511
```