Last updated at 2019-11-12
Reversing apps on a stock ROM can be challenging. Not only that we have to fight against unfriendly logics within the app, but also have to deal with various security restrictions (e.g. SELinux, debuggable flag) that the system once used to protect its innocent users.
Fortunately, Android is open-sourced and we are granted to modify whatever parts that we are not happy with. This write-up aims to provide an up-to-date guide on creating a customised Android build dedicated for reverse engineering purposes.
We use the folloing code branches/environments when writing this article, although most techniques should be easily applicable to a wide range of Android versions.
pie-gsi, built with
android-goldfish-4.4-dev, built with
There are a few goals that we want to achieve in this custom build:
The list below summaries the progress so far. Features labelled with "Done" will be available in our precompiled images.
Precompiled images, AOSP 9.0 + Kernel, x86_x64
Updated at: 2019-11-12
(Investigating) GameGuardian failed to run its daemon and complained "Unable to obtain root access". But our tests shows root is readily available:
generic_x86_64:/ # su u0_a68 generic_x86_64:/ $ whoami u0_a68 generic_x86_64:/ $ /system/xbin/su generic_x86_64:/ # whoami root