Without AppArmor a number of device features will not function properly and most apps will crash when launched. For more information on AppArmor, refer to the Ubuntu Wiki.
AppArmor is added through a combination of integrating the necessary code into the kernel source tree and setting necessary kernel configuration. The process is slightly different on Halium-7.1, compared to newer Halium versions.
AppArmor for Halium-7.1 ports¶
Start by downloading the backported AppArmor patch corresponding to your device’s kernel version. Your kernel version is specified at the beginning of your kernel defconfig file, i.e. the one you edited in section Modify the kernel configuration above. (For more information on backporting, see the bluetooth section below.)
You now need to delete your entire BUILDDIR/kernel/VENDOR/MODEL/security/apparmor subdirectory and replace it with the one you downloaded. Then rebuild
If you get errors when building, resolve them one at a time, modifying your source code as needed. Note that you should only modify the code in the AppArmor subdirectory if at all possible. Modifying code elsewhere will more than likely just compound your problems.
Seek help as needed from one of the sources mentioned in the subsection on getting community help.
Once you have successfully rebuilt
halium-boot.img, flash it to your device. If keyboard vibration works, this is a good indication that AppArmor has been successfully applied. Also, check if apps launch normally.
AppArmor for Halium-9.0 ports¶
When doing Halium-9.0 (and later) ports, it is generally sufficient to cherry pick certain commits to the kernel source rather than replacing the whole
apparmor directory in the kernel source tree. Follow the link below which corresponds to your device’s kernel version and select the most recent block of commits (i.e. all the commits that were added on the same and most recent date):
Make sure your kernel defconfig has the setting:
Now rebuild the boot image following your chosen build method, and flash it onto your device. Check if keyboard vibration works. This is a good indication that AppArmor has been successfully applied. Also, check if apps launch normally.