# honggfuzz-rs [![Build Status][travis-img]][travis] [![Crates.io][crates-img]][crates] [![Documentation][docs-img]][docs]
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[travis]: https://travis-ci.org/rust-fuzz/honggfuzz-rs
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[crates]: https://crates.io/crates/honggfuzz
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[docs]: https://docs.rs/honggfuzz
Fuzz your Rust code with Honggfuzz !
## [Documentation](https://docs.rs/honggfuzz)
[](https://asciinema.org/a/43MLo5Xl8ukHxgwDLArKqS9xc)
## About Honggfuzz
Honggfuzz is a security oriented fuzzer with powerful analysis options. Supports evolutionary, feedback-driven fuzzing based on code coverage (software- and hardware-based).
* project homepage [honggfuzz.com](http://honggfuzz.com/)
* project repository [github.com/google/honggfuzz](https://github.com/google/honggfuzz)
* this upstream project is maintained by Google, but ...
* this is NOT an official Google product
## Compatibility
* __Rust__: stable, beta, nightly
* __OS__: GNU/Linux, macOS, FreeBSD, Android, WSL (Windows Subsystem for Linux)
* __Arch__: x86_64, x86, arm64-v8a, armeabi-v7a, armeabi
* __Sanitizer__: none, address, thread, leak
## How to use this crate
Install honggfuzz commands to build with instrumentation and fuzz
```sh
# installs hfuzz and honggfuzz subcommands in cargo
cargo install honggfuzz
```
Add to your dependencies
```toml
[dependencies]
honggfuzz = "0.5"
```
Create a target to fuzz
```rust
#[macro_use] extern crate honggfuzz;
fn main() {
// Here you can parse `std::env::args and
// setup / initialize your project
// You have full control over the loop but
// you're supposed to call `fuzz` ad vitam aeternam
loop {
// The fuzz macro gives an arbitrary object (see `arbitrary crate`)
// to a closure-like block of code.
// For performance reasons, it is recommended that you use the native type
// `&[u8]` when possible.
// Here, this slice will contain a "random" quantity of "random" data.
fuzz!(|data: &[u8]| {
if data.len() != 6 {return}
if data[0] != b'q' {return}
if data[1] != b'w' {return}
if data[2] != b'e' {return}
if data[3] != b'r' {return}
if data[4] != b't' {return}
if data[5] != b'y' {return}
panic!("BOOM")
});
}
}
```
Fuzz for fun and profit !
```sh
# builds with fuzzing instrumentation and then runs the "example" target
cargo hfuzz run example
```
Once you got a crash, replay it easily in a debug environment
```sh
# builds the target in debug mode and replays automatically the crash in gdb
cargo hfuzz run-debug example fuzzing_workspace/*.fuzz
```
Clean
```sh
# a wrapper on "cargo clean" which cleans the fuzzing_target directory
cargo hfuzz clean
```
### Environment variables
#### `RUSTFLAGS`
You can use `RUSTFLAGS` to send additional arguments to `rustc`.
For instance, you can enable the use of LLVM's [sanitizers](https://github.com/japaric/rust-san).
This is a recommended option if you want to test your `unsafe` rust code but it will have an impact on performance.
```sh
RUSTFLAGS="-Z sanitizer=address" cargo hfuzz run example
```
#### `HFUZZ_BUILD_ARGS`
You can use `HFUZZ_BUILD_ARGS` to send additional arguments to `cargo build`.
#### `HFUZZ_RUN_ARGS`
You can use `HFUZZ_RUN_ARGS` to send additional arguments to `honggfuzz`.
See [USAGE](https://github.com/google/honggfuzz/blob/master/docs/USAGE.md) for the list of those.
For example:
```sh
# 1 second of timeout
# use 12 fuzzing thread
# be verbose
# stop after 1000000 fuzzing iteration
# exit upon crash
HFUZZ_RUN_ARGS="-t 1 -n 12 -v -N 1000000 --exit_upon_crash" cargo hfuzz run example
```
#### `HFUZZ_DEBUGGER`
By default we use `rust-lldb` but you can change it to `rust-gdb`, `gdb`, `/usr/bin/lldb-7` ...
## Relevant documentation about honggfuzz
* [USAGE](https://github.com/google/honggfuzz/blob/master/docs/USAGE.md)
* [FeedbackDrivenFuzzing](https://github.com/google/honggfuzz/blob/master/docs/FeedbackDrivenFuzzing.md)
* [PersistentFuzzing](https://github.com/google/honggfuzz/blob/master/docs/PersistentFuzzing.md)
## About Rust fuzzing
There is other projects providing Rust fuzzing support at [github.com/rust-fuzz](https://github.com/rust-fuzz).
You'll find support for [AFL](https://github.com/rust-fuzz/afl.rs) and LLVM's [LibFuzzer](https://github.com/rust-fuzz/cargo-fuzz) and there is also a [trophy case](https://github.com/rust-fuzz/trophy-case) ;-) .
This crate was inspired by those projects!