AppArmor

AppArmor is a kernel security module that restricts individual programs' capabilities. This can allow administrators to prevent programs accessing system resources in malicious ways according to per-applications specifications. AppArmor works by following profiles, which dictate what each application is and is not allowed to do. 
== Installation ==
You should also install apparmor-utils if you want to use the aa command to interact with AppArmor.
==Setup==
Run the command to see what linux security modules are currently setup. 
=== With SYSLINUX ===
Use a text editor of your choice (preferably a TUI based one since some GUI setups don't work with privilege escalation, unless you use sudo -e) to edit such that the APPEND line ends with the following:
lsm=landlock,yama,apparmor
Note that because you're including lsm in this .conf file you are overriding the default lsm. Thus, you should include any lsm that you saw previously running in the above cat command. Additionally, lsm initializes these modules in order, so their position is important in regards to major/minor modules. Ensure that apparmor is placed first among major modules. Note for convenience that yama, capability, and landlock, which come with Alpine Linux, are not major modules, and apparmor can be placed after them. The module called capability is automatically included and does not need to be written in.
To persist your changes between kernel updates (which overwrite ), edit , and append your lsm=landlock,yama,apparmor parameter to default_kernel_opts.
=== With GRUB ===
Add the following at the end of the value for key GRUB_CMDLINE_LINUX_DEFAULT to :
apparmor=1 security=apparmor
Then apply with:
== Running ==
Next, start AppArmor and tell OpenRC to start it on boot.
You can check if AppArmor is running with the command aa-enabled
== Configuration ==
AppArmor works using rules established in profiles. A set of pre-made profiles is available for ease of use:
Reboot following installation
=== Enabling Extra Profiles ===
Extra profiles reside in . In order to enable to profile, it needs to be copied to :
If you want to enable the profile for usr.bin.chromium-browser, for example:
This will install the profile, it then needs to be set to complain or enforce mode:
=== Creating additional profiles ===
The profiles provided by the apparmor-profiles package are just a starter. You can create your own profiles, but first you must install and start audit
 
Now you can generate your own profiles with
or
Note that for this to work you'll probably need to set a more verbose kernel log level. For improved security, set it back to a higher level afterwards.
== Use ==
View AppArmor's report:
This details how many and what profiles are in use as well as relevant findings, such as how many profiles are in complain mode or in kill mode.
== Troubleshooting ==
If you notice a bunch of AppArmor errors on boot, try running aa-status and aa-enabled in the terminal. If the output mentions AppArmor being disabled at boot, re-open your file and make sure the APPEND line still ends with lsm=landlock,yama,apparmor
== See Also ==
* AppArmor Wiki
* Debian Wiki: How to use AppArmor
* AppArmor entry on ArchWiki
Category:Security
Category:Kernel