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librephone Project

This is a project to research proprietary files in Android to work towards a long-term goal of free replacements. While there are many proprietary libraries and other files in Android, this project is focused on binary blobs. Initially the research is focused on identifying the best device for software development. And also documenting how the blobs get used by the kernel as a guide to what it would take to clean-room legally reverse engineer them.

If there is sufficient interest and funding, a detailed specification can be written and used to have somebody code a free implementation that works the same way.

Lineage Packages

  • Comparing Devices This describes the process of analyzing all the binary blobs in the devices supported by Lineage.

  • File Structure This describes the top level blobs found in a Lineage package.

Technical Details

  • Tools This covers all the free and open source tools I use for reverse engineering.

  • AARCH32 Thumb Mode This covers how to dissasemble AARCH32, which supports 2 instruction sets.

  • WPSS This describes the Wireless Processor SubSystem.

Utility Programs

This project contains several utilities for analyzing proprietary files and binary blobs in Android. They are oriented towards any developers wishing to duplicate the research on their own. If you want to use these, chances are you might have to edit a few paths.

These utilities require you have download the Lineage install package for the devices you are interested in researching. There is also a top level script images_util.sh that can automate the processing of multiple devices.

  • extractor.py This is a simple utility to unpack and mount the system files from the Lineage packaged installer file.

  • import_dev.py Import data on all proprietary files and binary blobs into a database so they can be better analyzed.

  • query_dev.py This script does common SQL queries and dumps them as CSV file.

  • generator.py This program uses a YAML config file to generate bindings for Python or Postgres.

    • Code Stubs This documents the format of the config files for the generator.

  • images_util.sh This is only for developers who want to reproduce the research by analyzing the multiple devices supported by Lineage.

Data Files

These are extracts from the database produced by the query_devices.py program in CSV format. These can be further analyzed by using a spreadsheet program.