Fcd+Remill

Fcd+Remill is a fork of the original native program decompiler fcd. It has a three stage decompilation architecture which uses Remill for translating x86 and amd64 machine code (including AVX and AVX512) into LLVM bitcode, performs transformation passes over the bitcode and then uses the pattern-independent structuring algorithm to a goto-free C-like output.

The design philosophy behind the project is to provide a relatively small and easily hackable codebase with great interoperability with other LLVM and Remill-based projects.

Future goals include AArch64 support, support for Fcd+Remill usable as a Python module and steadily improved recovery and presentation of advanced native code constructs, such as jump-tables and virtual calls.

Build Status

	master
Linux

Getting Help

If you are experiencing undocumented problems with Fcd+Remill then ask for help in the #binary-lifting channel of the Empire Hacking Slack.

Supported Platforms

Fcd+Remill is supported on Linux platforms and has been tested on Ubuntu 16.04.

Dependencies

Most of Fcd+Remill's dependencies can be provided by the cxx-common repository. Trail of Bits hosts downloadable, pre-built versions of cxx-common, which makes it substantially easier to get up and running with Fcd+Remill. Nonetheless, the following table represents most of Fcd+Remill's dependencies.

Name	Version
Git	Latest
CMake	3.2+
Google Flags	Latest
Google Log	Latest
LLVM	3.5+
Clang	3.5+
Remill	Latest
Python	2.7
Zlib	Latest
Unzip	Latest

Getting and Building the Code

On Linux

First, update aptitude and get install the baseline dependencies.

sudo apt-get update
sudo apt-get upgrade

sudo apt-get install \
     git \
     python2.7 \
     wget \
     realpath \
     build-essential \
     libtinfo-dev \
     python-dev \
     libz-dev \
     lsb-release

The next step is to clone the Remill repository. We then clone the Fcd repository into the tools subdirectory of Remill. This is kind of like how Clang and LLVM are distributed separately, and the Clang source code needs to be put into LLVM's tools directory.

git clone https://github.com/trailofbits/remill.git
cd remill/tools/
git clone https://github.com/trailofbits/fcd.git

Finally, we build Remill along with Fcd. This script will create another directory, remill-build, in the current working directory. All remaining dependencies needed by Remill will be built in the remill-build directory.

cd ../../
./remill/scripts/build.sh

To try out Fcd+Remill you can do the following, given an amd64/linux binary of your choice.

./remill-build/tools/fcd/fcd -arch amd64 -os linux mybinary.out

lifting-bits / fcd