GTIRB Stack Stamp

This repository holds example implementations of binary transformations implemented over top of GTIRB. See the accompanying GTIRB Tutorial for more information.

Specifically, this example repository implements a transform to apply 'stack stamping' protections to a binary.

Abstract

Stack stamping is a technique to help mitigate ROP style attacks. This is done by 'stamping' the return address on the stack, thus encrypting it. Before it is popped off the stack and used, it is decrypted by 'un-stamping' it. This can be an efficient protection, as no registers are needed, and while flags are affected, they are only affected at function entry/exits where they do not need to be preserved. By encoding and decoding this return address, an attacker has a more difficult task, since the replacement data would need to be properly encoded, such that when it is un-stamped, it results in the desired address.

Building

This repository contains three implementations of stack-stamping in three different languages:

Python
C++
Common Lisp

Python

The Python transform requires some dependencies to be installed:

pip3 install gtirb-capstone gtirb-functions capstone keystone-engine

To starting using it, run:

python3 setup.py develop

To invoke the command line utility thus generated:

python3 -m gtirb_stack_stamp

C++

This transform depends on the following libraries:

Boost (version 1.67 or later)
GTIRB
Capstone
Keystone

Ensure they are installed before compiling the C++ version of the transform. Building from source also depends on CMake being installed.

Options

We add the filling CMake options during building:

GTIRB_STACK_STAMP_ENABLE_TESTS: Set to OFF to disable the downloading of Google Test and the building of the test executable. ON by default.
GTIRB_STACK_STAMP_BUILD_SHARED_LIBS: Set to OFF to build static libraries instead of dybnamic ones. ON by default.

On Linux

cmake -Bbuild ./
cd build
make

The generated command-line utility will then be available in build/bin.

On Windows

Currently, some issues are preventing Keystone from being built on Windows, so the C++ version of gtirb-stack-stamp is buildable on Linux only for the time being.

Tests

Our CMake automatically downloads a local copy of Google Test and produces a test executable. To run it:

build/bin/test-gtirb-stack-stamp

You will need gtirb-pprinter and ddisasm on your PATH.

Common Lisp

The Common Lisp transform requires the following external libraries:

and the following common lisp packages (gtirb, gtirb-functions, gtirb-capstone) which may be installed via QuickLisp:

Clone this repository into your ~/quicklisp/local-projects directory
```
git clone https://github.com/grammatech/gtirb-stack-stamp
```
Load gtirb-stack-stamp and all dependencies.
```
(ql:quickload :gtirb-stack-stamp)
```

To run the transform at the REPL:

(write-gtirb (stack-stamp (drop-cfi (read-gtirb "in.gtirb"))) "out.gtirb")

To build the command line executable:

sbcl --eval '(ql:quickload :gtirb-stack-stamp)' \
     --eval '(asdf:make :gtirb-stack-stamp :type :program :monolithic t)'