clixon/fuzz/backend

Clixon fuzzing

This dir contains code for fuzzing clixon backend.

It requires the preeny package to change sockets to stdio.

Prereqs

Preeny has a "desocketizing" module necessary to map stdio to the internal sockets that the backend uses. Install preeny example:

  sudo apt install libini-config-dev # debian/ubuntu
  sudo apt install libseccomp-dev # debian/ubuntu
  git clone https://github.com/zardus/preeny.git
  cd preeny
  make
  sudo cp x86_64-linux-gnu/desock.so /usr/local/lib/ # install

See AFL docs for installing afl. On ubuntu this may be enough:

  sudo apt install afl

You may have to change cpu frequency:

  cd /sys/devices/system/cpu
  echo performance | tee cpu?/cpufreq/scaling_governor

And possibly change core behaviour:

  echo core >/proc/sys/kernel/core_pattern

Build

Make a modification to how Clixon sends internal messages in include/clixon_custom.h:

  #define CLIXON_PROTO_PLAIN

Build clixon statically with the afl-clang compiler:

  CC=/usr/bin/afl-clang-fast LINKAGE=static ./configure --with-restconf=evhtp
  make clean
  make
  sudo make install

Run tests

Populate the input/ dir with input usecases, there are two examples already in this dir that can be modified. Use the script runfuzz.sh to run one test:

  ./runfuzz.sh

After (or during) the test, investigate results in the output dir.