Il2CppInspector

Extract types, methods, properties and fields from Unity IL2CPP binaries.

• Supports ELF (Android .so), PE (Windows .exe), Mach-O (Apple iOS/Mac) and Universal Binary (Fat Mach-O) file formats
• Supports ARMv7, ARMv7 Thumb T1 and x86 architectures regardless of file format
• Supports metadata versions 21, 22, 23, 24, 24.1 (Unity 2018.3+) and 24.2 (Unity 2019+)
• No manual reverse-engineering required; all data is calculated automatically
• Support for classes, methods, fields, properties, enumerations, events, delegates, interfaces, structs and default field values
• Static and dynamic symbol table scanning for ELF binaries if present
• Il2CppInspector re-usable class library for low-level access to IL2CPP binaries and metadata
• Il2CppReflector re-usable class library for high-level .NET Reflection-style access to IL2CPP types and data as a tree model
• Test chassis for automated integration testing of IL2CPP binaries

Class library targets .NET Standard 2.1. Application targets .NET Core 3.0. Built with Visual Studio 2019.

Build instructions

git clone --recursive https://github.com/djkaty/Il2CppInspector
cd Il2CppInspector
dotnet restore -r win7-x86
dotnet publish -c Release -r win7-x86

This will build Il2CppInspector for Windows 7 and later. For MacOS and Linux, replace win7-x86 with a RID from https://docs.microsoft.com/en-us/dotnet/articles/core/rid-catalog

The output binary is placed in Il2CppInspector/Il2CppDumper/bin/Release/netstandard1.6/win7-x86/publish.

Usage

Il2CppDumper [<binary-file> [<metadata-file> [<output-file>]]]

Defaults if not specified:

• binary-file - searches for libil2cpp.so and GameAssembly.dll
• metadata-file - global-metadata.dat
• output-file - types.cs

File format and architecture are automatically detected.

For Apple Universal Binaries, multiple output files will be generated, with each filename suffixed by the index of the image in the Universal Binary. Unsupported images will be skipped.

64-bit binaries

Il2CppInspector does not currently support 64-bit IL2CPP binaries. 64-bit Mach-O files will be parsed without crashing but there is currently no support for 64-bit CPU architectures so automatic inspection will fail.

Running tests

Two Powershell scripts are provided to enable easy testing and debugging:

• generate-binaries.ps1 compiles every C# source file in TestSources as a separate assembly and outputs them to TestAssemblies. It then takes every assembly in TestAssemblies and compiles each one as a separate IL2CPP project twice: one for Windows x86 standalone and one for Android into the TestBinariesfolder. It then calls generate-tests.ps1.
• generate-tests.ps1 generates a file called Tests.cs in the Il2CppTests project, containing one test per IL2CPP project in TestBinaries. This file will be compiled by the Il2CppTestsproject. You will then be able to see one test per IL2CPP project in Visual Studio's Test Explorer.

The auto-generated tests generate a file in the test IL2CPP binary's folder called test-result.cs and compares it (whitespace-insensitive) with the corresponding project name cs file in TestExpectedResults. In this way, you can check for files with known structure that the analysis is being performed correctly, or step through the analysis of specific binaries in the debugger without having to change the project's command-line arguments.

Problems

If you have files that don't work or are in an unsupported format, please open a new issue on GitHub and attach a sample with details on the file format, and I'll try to add support.

Acknowledgements

Thanks to the following individuals whose code and research helped me develop this tool:

• Perfare - https://github.com/Perfare/Il2CppDumper
• Jumboperson - https://github.com/Jumboperson/Il2CppDumper
• nevermoe - https://github.com/nevermoe/unity_metadata_loader
• branw - https://github.com/branw/pogo-proto-dumper
• fry - https://github.com/fry/d3
• ARMConvertor - http://armconverter.com

This tool uses Perfare's Il2CppDumper code as a base.

License

All rights reserved. Unauthorized use, re-use or the creation of derivative works of this code for commercial purposes whether directly or indirectly is strictly prohibited. Use, re-use or the creation of derivative works for non-commercial purposes is expressly permitted.