3.6 KiB
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
.
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.so
to find the location of your harness, then run
./frida_fuzzer -F LLVMFuzzerTestOneInput -H ./libpng-harness.so -l ./libpng-harness.so
Windows
You can also fuzz libpng-1.6.37 on windows with frida mode
To build it with visual studio
-
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
-
Download libpng-1.6.37[https://deac-fra.dl.sourceforge.net/project/libpng/libpng16/1.6.37/libpng-1.6.37.tar.xz] and zlib [https://zlib.net/fossils/zlib-1.2.11.tar.gz] into this directory, and rename
zlib-1.2.11
directory tozlib
. -
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
-
Compile the harness Fire up a powershell at this directory.
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
- Run the fuzzer
./frida_fuzzer.exe ./libpng-harness.dll LLVMFuzzerTestOneInput ./libpng-harness.dll