FRET-LibAFL/fuzzers/frida_libpng/README.md

Libfuzzer for libpng

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 link (the fuzzer)[./src/fuzzer.rs] against (the C++ harness)[./harness.cc] and the instrumented libpng. Afterwards, the fuzzer will be ready to run, from target/frida_libpng.

Build For Android

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

1. 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"
2. add path to installed toolchain to PATH env variable.
3. 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, too, you can run find . -name libpng-harness.so to find the location of your harness, then run ./target/release/frida_libpng ./libpng-harness.so LLVMFuzzerTestOneInput ./libpng-harness.so --cores=0

Windows

You can also fuzz libpng-1.6.37 on windows with frida mode!

To build it with visual studio

1. Install clang for windows (make sure you add LLVM to the system path!) https://github.com/llvm/llvm-project/releases/tag/llvmorg-12.0.1
2. Build libpng1.6.37
   • Open libpng-1.6.37/projects/vstudio/vstudio.sln
   • Open Build->Configuration Manager
     • select Release for Active solution configuration and
     • select ->x64 for Active solution platform (Copy settings from Win32)
   • Then for libpng, pngstest, pngtest, pngunknown, pngvalid, zlib in Solution Explorer, choose General -> Configuration Type -> Static library(.lib)
     • C/C++ -> Treat Warnings As Errors -> No
     • C/C++ -> Code Generation -> Runtime Library -> Multi-threaded (/MT)
   • Finally, you can build libpng-1.6.37
3. Compile the harness Fire up a powershell at this directory.

cargo build --release
cp .\libpng-1.6.37\projects\vstudio\x64\Release\libpng16.lib .
cp .\libpng-1.6.37\projects\vstudio\x64\Release\zlib.lib .
cp .\target\release\frida_libpng.exe .
clang++ -O3 -c -I.\libpng-1.6.37 .\harness.cc -o .\harness.o
clang++ -L.\zlib.dll .\harness.o .\libpng16.lib -lzlib -shared -o .\libpng-harness.dll

4. Run the fuzzer

./frida_libpng.exe ./libpng-harness.dll LLVMFuzzerTestOneInput ./libpng-harness.dll --cores=0

To build it with msys2

1. Install and setup msys2 (https://www.msys2.org/)
2. (Optional) If you prefer to compile libpng with clang, you can install it and its dependecy with

pacman -S mingw-w64-x86_64-clang
pacman -S mingw-w64-clang-x86_64-zlib

and

export LDFLAGS='-L/clang64/lib'
export CPPFLAGS='-I/clang64/include'
export CC=clang
export CXX=clang++

3. Compile frida_libpng (possibly from your powershell)

cargo build --release
cp ./target/release/frida_libpng.exe .

4. Compile libpng-1.6.37 with the following commands

cd libpng-1.6.37
./configure --enable-hardware-optimizations=yes --with-pic=yes
make
cd ..

5. Compile the harness with gcc or clang++

g++ -O3 -c -I./libpng-1.6.37 -fPIC harness.cc -o harness.o
g++ -O3 harness.o ./libpng-1.6.37/.libs/libpng16.a -static -shared -lz -o libpng-harness.dll

or

clang++ -O3 -c -I./libpng-1.6.37 -fPIC harness.cc -o harness.o
clang++ -O3 harness.o ./libpng-1.6.37/.libs/libpng16.a -static -shared -lz -o libpng-harness.dll

6. Run the fuzzer

./frida_libpng.exe ./libpng-harness.dll LLVMFuzzerTestOneInput ./libpng-harness.dll --cores=0