This folder contains an example fuzzer for libpng, using LLMP for fast multi-process fuzzing and crash detection. To show off crash detection, we added a ud2 instruction to the harness, edit harness.cc if you want a non-crashing example. It has been tested on Linux.

Build

To build this example, run cargo build --release in this folder. This will call (the build.rs)[./build.rs], which in turn downloads a libpng archive from the web. Then, it will build (the C++ harness)[./harness.cc] and the instrumented libpng. Then, it will create frida fuzzer shared library in ./target/release/libfrida_fuzzer.so. On unix platforms, you'll need libc++ to build it.

Alternatively you can run cargo make run and this command will automatically build and run the fuzzer

Build For Android

When building for android using a cross-compiler, make sure you have a standalone toolchain, and then add the following:

In the ~/.cargo/config file add a target with the correct cross-compiler toolchain name (in this case aarch64-linux-android, but names may vary) [target.aarch64-linux-android] linker="aarch64-linux-android-clang"
add path to installed toolchain to PATH env variable.
define CLANG_PATH and add target to the build command line: CLANG_PATH=<path to installed toolchain>/bin/aarch64-linux-android-clang cargo -v build --release --target=aarch64-linux-android

Run

This example uses in-process-fuzzing, using the launcher feature, in combination with a Restarting Event Manager. This means running --cores each client will start itself again to listen for crashes and timeouts. By restarting the actual fuzzer, it can recover from these exit conditions.

After building the libpng-harness, you can run find . -name libpng-harness to find the location of your harness, then run

LD_PRELOAD=./target/release/libfrida_fuzzer.so ./libpng-harness -i corpus -o out -l ./libpng-harness.so