libdevbinder

libdevbinder is a C library that simplifies interaction with binder (Android IPC subsystem). It abstracts the complexities of ioctl calls into a familiar send/receive socket-like interface, making it easier to develop programs that perform IPC via Binder. It supports both Linux and Android platforms on x86_64 and arm64 architectures.

This is not an officially supported Google product

Clone and Build

Clone the repository

git clone https://github.com/androidoffsec/libdevbinder.git

Run make to build libdevbinder.a and other examples.

make

The default target architecture is x86_64. To cross compile for arm64:

ARCH=arm64 make

To compile for Android using Android NDK:

export NDK_ROOT=/path/to/android-ndk
ANDROID=1 make

Android Studio Project

To include libdevbinder as a dependency in your Android application, follow these steps:

1. Create a new Native C++ project
2. Clone the repository under src/main/cpp.

cd /path/to/app/src/main/cpp
git clone https://github.com/androidoffsec/libdevbinder.git

In src/main/cpp/CMakeLists.txt,

3. Include libdevbinder as a submodule.

add_subdirectory(libdevbinder)

4. Link the target object with devbinder or devbinder_static.

# Link the shared library
target_link_libraries(${CMAKE_PROJECT_NAME} ... devbinder)

# Link the static library
target_link_libraries(${CMAKE_PROJECT_NAME} ... devbinder_static)

Examples

By default, all examples connect to the /dev/binder device.

Note: Running these examples directly on an Android device might not work as expected. This is because the context manager is already assigned to the ServiceManager process.

On a rooted Android device, you can create a new binder device node by mounting a new binderfs file system:

mkdir /dev/mybinder
mount -t binder binder /dev/mybinder

Then, modify the example code to connect to /dev/mybinder/binder instead of /dev/binder.

Server

Run the server to listen for incoming transactions and display them. The server sets itself as the context manager.

./server

Client

Run the client to send a hello world message to the context manager (server).

./client "hello world"

Contributing

Contributions are welcome; see CONTRIBUTING.md.

License

This project is licensed under the terms of Apache license 2.0; see LICENSE.

Security

This library is intended for educational purposes only. Please submit a PR for security fixes, but do not open an issue, request a CVE, or submit the issue to any bug bounty programs.