# Fluff

**Repository Path**: mirrors_Samsung/Fluff

## Basic Information

- **Project Name**: Fluff
- **Description**: A tool designed to synthesise semantically correct JavaScript snippets given arbitrary data.  Useful for fuzzing.
- **Primary Language**: Unknown
- **License**: MIT
- **Default Branch**: master
- **Homepage**: None
- **GVP Project**: No

## Statistics

- **Stars**: 0
- **Forks**: 0
- **Created**: 2020-09-25
- **Last Updated**: 2026-05-24

## Categories & Tags

**Categories**: Uncategorized

**Tags**: None

## README

# Fluff
A tool designed to synthesise semantically correct JavaScript snippets given arbitrary data.

Useful for fuzzing.

# JS Runtimes supported out-of-the-box
* [jerryscript](https://github.com/pando-project/jerryscript)
* [njs](https://hg.nginx.org/njs)
* [duktape](https://duktape.org/download.html)
* [v8](https://v8.dev/)

# Requirements
* docker
* make

# Building
* (optional) Check if you have access to docker (run ```docker info```)
* (optional) Specify desired version of JS runtime in ```Makefile.conf```
* Run ```make (jerryscript | njs | duktape | v8)```
* If everything builds correctly the process will result in:
    * build/fluff_* - binary to fuzz
    * build/fluff_*_dry - binary that will convert Fluff bytecode to JS testcase (stdout)
    * build/grammars
        * js_grammar.yaml - es5.1 grammar file
        * js_grammar_es6.yaml - es6 grammar file

# Usage
Typical fuzzing setup:

* Create input folder and sample testcase, i.e. ```mkdir in && echo "420" >> in/testcase```
* Start fuzzing using `afl-fuzz`, for example: `afl-fuzz -m none -i in -o out ./fluff_njs @@ js_grammar.yaml`
* (optional) you can use build container to run fuzzing, requires some manual work
```
docker run -it -d -v path/to/fluff/repository/build:/home/build/fluff identifier /bin/bash
docker exec -it container_number bash
# afl-fuzz is preinstalled in /home/build/afl
```

* Enjoy your cup of tea/coffee and wait for crashes

# Description
Detailed information about the design of Fluff can be read in the [whitepaper](https://i.blackhat.com/asia-19/Fri-March-29/bh-asia-Dominiak-Efficient-Approach-to-Fuzzing-Interpreters-wp.pdf).

# Contributing
Patches, additions and other contributions are welcome! If you see a feature which you could implement or a bug which you could fix please send us a message or a pull request. If you have found some interesting bug with this tool, please leave us a message/github issue for the future Hall Of Fame.

# Contact
If you want to drop us a message, feel free to send a mail to <m.dominiak@samsung.com> or <w.rauner@samsung.com>.