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
• Building
• Usage

Structure

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

   +--IPCFG--Edges...........................
   |                 .                      .
   |         +-ProxyBlocks             +-CodeBlocks
   |         |                         |
IR-+-Modules-+-Sections--ByteIntervals-+-DataBlocks
   |    |    |                         |
   |    |    +-Symbols.........        +-SymbolicExpressions
   +-AuxData                  .              .
    --------                  ................
    ID0|DATA0
    ID1|DATA1....*anything*
    ID2|DATA2

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.

Building

GTIRB 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 3.9.

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.
bin/TestGTIRB

Requirements

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

• CMake, version 3.9.0 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.

Usage

GTIRB is designed to be serialized using Google's 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

The serialized protobuf data produced by GTIRB 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. For language-independent API information, see GTIRB Components. For information about the different API implementations, see:

• C++ API
• Python API
• Common Lisp API