DeClang

_{日本語はこちら}

Introduction

DeClang is an anti-hacking compiler based on LLVM project and extented the OSS project ollvm (https://github.com/obfuscator-llvm/obfuscator).

We open sourced some of the obfuscation features of DeClang for now. Some other features might be open sourced in the future.

DeClang is a compiler based anti-hack solution and has a lot of advantages over packer based solution. For the detailed comparision, please refer to the following document. https://www.slideshare.net/dena_tech/declang-clang-dena-techcon-2020

Supported Architecture

Supported host architecture

• x64 macOS
• x64 Linux
• x64 Windows

Supported target architecture

• arm / arm64 ELF (Android)
• arm / arm64 Mach-O (iPhone)
• x86 / x64 ELF (Linux)
• x86 / x64 Mach-O (macOS)

Build

$ git clone https://github.com/DeNA/DeClang
$ cd DeClang/script
$ bash build.sh
...
$ bash build_tools.sh
...
$ bash android_release.sh v1.0.0
...

Then you have a Release-v1.0.0 folder in the root directory of DeClang.

Installation & Setup

• Define DECLANG_HOME environment variable

  export DECLANG_HOME=/path/to/declang_home/
  

• Copy Release folder to $DECLAHG_HOME

  • If you built DeClang by yourself
    • Copy Release-v1.0.0 to $DECLANG_HOME/.DeClang.

    mv Release-v1.0.0 $DECLANG_HOME/.DeClang
    

  • If you downloaded pre-built binary from Releases page.
    • Decompress the zip file and copy the Release folder to $DECLANG_HOME/.DeClang.

    mv Release/ $DECLANG_HOME/.DeClang
    

• Setup DeClang for android-ndk:

  bash $DECLANG_HOME/.DeClang/script/ndk_setup.sh {/path/to/ndk_root}
  

  Recover the original NDK:

  bash $DECLANG_HOME/.DeClang/script/ndk_unset.sh {/path/to/ndk_root}
  

• Setup DeClang for Xcode:

  bash $DECLANG_HOME/.DeClang/script/xcode_setup.sh -x {/path/to/Xcode.app} -p {/path/to/xcodeproject.xcodeproj}
  

  Recover the original xcode project file:

  bash $DECLANG_HOME/.DeClang/script/xcode_unset.sh {/path/to/xcodeproject.xcodeproj}
  

• Now you can build your project using your usual build pipeline.

Configuration

• Edit config.pre.json in $DECLANG_HOME/.DeClang/ folder:

  vi $DECLANG_HOME/.DeClang/config.pre.json
  

• Generate config.json from config.pre.json:

  $DECLANG_HOME/.DeClang/gen_config_mac -path $DECLANG_HOME/.DeClang/ -seed {your seed}
  

  "seed" can be any string. You should change "seed" for each build.

Unity Support

If you are building your Unity project using command line then set the DECLANG_HOME in comand line is sufficient. But if you are building a Unity project using GUI, you should set the DECLANG_HOME environment variable in your build script:

System.Environment.SetEnvironmentVariable("DECLANG_HOME", "/path/to/DeClang/");

Notes

• If you do not set DECLANG_HOME, DeClang will use the default directory ~/.DeClang/
• Note that usually DeClang for NDK and DeClang for Xcode might not be compatitable with each other so when you install & setup DeClang for different architecture please make sure you are using the correct DeClang version.