GTIRB

The GrammaTech Intermediate Representation for Binaries (GTIRB) is a machine code analysis and rewriting data structure. It is intended to facilitate the communication of binary IR between programs performing binary disassembly, analysis, transformation, and pretty printing. GTIRB is modeled on LLVM-IR, and seeks to serve a similar functionality of encouraging communication and interoperability between tools.

The remainder of this file describes various aspects of GTIRB:

• Structure
• Installing
• Building
• Usage

Structure

GTIRB has the following structure. Solid lines denote inheritance. Dotted lines denote reference by UUID.

IR

An instance of GTIRB may include multiple modules (Module) which represent loadable objects such as executables or libraries, an inter-procedural control flow graph (IPCFG), and Auxiliary Data tables (AuxData) which can hold arbitrary analysis results in user-defined formats which can easily reference other elements of the IR. Each module holds information such as symbols (Symbol) and sections which themselves hold the actual bytes and data and code blocks of the module. The CFG consists of basic blocks (Block) and control flow edges between these blocks. Each data or code block references a range of bytes in a byte interval (ByteInterval). A section may hold one large byte interval holding all blocks---if the relative positions of blocks in that section are defined---or may hold one byte interval per block---if the relative positions of blocks is not defined, e.g. for the code blocks in the .text section during program rewriting. Each symbol holds a pointer to the block or datum it references.

Instructions

GTIRB explicitly does NOT represent instructions or instruction semantics but does provide symbolic operand information and access to the bytes. There are many intermediate languages (IL)s for representation of instruction semantics (e.g., BAP's BIL, Angr's Vex, or Ghidra's P-code). GTIRB works with these or any other IL by storing instructions generally and efficiently as raw machine-code bytes and separately storing the symbolic and control flow information. The popular Capstone/Keystone decoder/encoder provide an excellent option to read and write instructions from/to GTIRB's machine-code byte representation without committing to any particular semantic IL. By supporting multiple ILs and separate storage of analysis results in auxiliary data tables GTIRB enables collaboration between independent binary analysis and rewriting teams and tools.

Auxiliary Data

GTIRB provides for the sharing of additional information, e.g. analysis results, in the form of AuxData objects. These can store maps and vectors of basic GTIRB types in a portable way. The GTIRB manual describes the structure for common types of auxiliary data such as function boundary information, type information, or results of common analyses in Standard AuxData Schemata.

UUIDs

Every element of GTIRB---e.g., modules (Module), symbols (Symbol), and blocks (Block)---has a universally unique identifier (UUID). UUIDs allow both first-class IR components and AuxData tables to reference elements of the IR.

Instructions and symbolic operands can be addressed by the class Offset which encapsulates a UUID (that refers to the instruction's block) and an offset.

Installing

Packages currently exist for easily installing GTIRB (and attendant tooling including the ddisasm disassembler and gtirb-pprinter pretty printer) on Windows, and Ubuntu 20. See below for instructions. Additionally, a public Docker image exists at grammatech/ddisasm with all of these tools installed. GTIRB is versioned with Major.Minor.Patch versioning where Major version increments will require significant source changes but should be very rare, Minor version increments may require small source changes, and Patch version increments shouldn't break any downstream builds. We do not yet provide ABI compatibility across any version changes.

Python API

The latest stable GTIRB Python API may be installed from PyPI using pip:

pip install gtirb

The latest unstable version of the Python API can be installed from a prebuilt wheel:

pip install https://download.grammatech.com/gtirb/files/python/gtirb-unstable-py3-none-any.whl

It is critical that the choice of a stable or unstable package matches the installed ddisasm and gtirb-pprinter packages.

Windows

Windows releases are packaged as .zip files and are available at https://download.grammatech.com/gtirb/files/windows-release/.

Ubuntu

Packages for Ubuntu 20 are available in the GTIRB apt repository and may be installed per the following instructions.

First, add GrammaTech's APT key.

wget -O - https://download.grammatech.com/gtirb/files/apt-repo/conf/apt.gpg.key | apt-key add -

Next update your sources.list file.

echo "deb [arch=amd64] https://download.grammatech.com/gtirb/files/apt-repo [distribution] [component]"| sudo tee -a /etc/apt/sources.list

Where:

• [distribution] is focal (currently, only Ubuntu 20 packages are available)
• [component] is either stable, which holds the last versioned release, or unstable, which holds the HEAD of the repository.

Finally update your package database and install the core GTIRB tools:

sudo apt-get update
sudo apt-get install gtirb-pprinter ddisasm

Warning: There is a problem with the packages in the stable repository that will cause conflicts if you try apt-get upgrade. In this case, uninstall and reinstall the packages you got from the GTIRB repository. You may need to use dpkg --remove to remove the metapackages (e.g. ddisasm) before removing the concrete versioned packages (e.g. ddisasm-1.5.1).

Building

GTIRB's C++ API should successfully build in 64-bits with GCC, Clang, and Visual Studio compilers supporting at least C++17. GTIRB uses CMake which must be installed with at least version 3.10.

The common build process looks like this:

mkdir build
cd build
# Note: You may wish to add some -D arguments to the next command. See below.
cmake <path/to/gtirb>
cmake --build .
# Run the test suite.
ctest

For customizing the GTIRB build, you can get a list of customization options by navigating to your build directory and running:

cmake -LH

Requirements

To build and install GTIRB, the following requirements should be installed:

• CMake, version 3.10.0 or higher.
  • Ubuntu 18 provides this version via the APT package cmake.
  • Ubuntu 16 and earlier provide out of date versions; build from source on those versions.
• Protobuf, version 3.0.0 or later.
  • Ubuntu 18 provides this version via the APT packages libprotobuf-dev and protobuf-compiler.
  • Ubuntu 16 and earlier provide out of date versions; build from source on those versions.
• Boost (non-standard Ubuntu package from launchpad.net), version 1.67 or later.
  • Ubuntu 18 only has version 1.65 in the standard repository. See Ubuntu instructions above.

Usage

GTIRB is designed to be serialized using Google protocol buffers (i.e., protobuf), enabling easy and efficient use from any programming language.

GTIRB may also be used through a dedicated API implemented in multiple languages. The APIs provide efficient data structures suitable for use by binary analysis and rewriting applications; see below for details.

Using Serialized GTIRB Data

GTIRB uses a serialized format that consists of an 8-byte signature followed by serialized protobuf data. The protobuf data allows for exploration and manipulation in the language of your choice. The Google protocol buffers homepage lists the languages in which protocol buffers can be used directly; users of other languages can convert the protobuf-formatted data to JSON format and then use the JSON data in their applications.

The proto directory in this repository contains the protocol buffer message type definitions for GTIRB. You can inspect these .proto files to determine the structure of the various GTIRB message types. The top-level message type is IR.

For more details, see Using Serialized GTIRB Data.

GTIRB API Implementations

The GTIRB API is currently available in C++, Python, and Common Lisp. There is a partial Java API which is not ready for external use. For language-independent API information, see GTIRB Components. For information about the different API implementations, see:

• C++ API
• Python API
• Common Lisp API
• Java API incomplete