fusil-numpy-plugin

A numpy fuzzing plugin for fusil's Python fuzzer.

It injects a large catalog of pre-built "tricky" numpy arrays and scalars (odd dtypes, huge/empty shapes, NaN/inf, object arrays, non-contiguous views, ...) as hostile arguments into fuzzed calls, and embeds their setup code into every generated script.

Unlike the h5py and cereggii plugins — which only activate when their library is the fuzz target — numpy arrays are useful hostile inputs for any C extension, so this plugin is active for every run whenever numpy is importable. This reproduces the behaviour of the in-core numpy support it replaces.

This machinery used to live in-tree (fusil/python/samples/tricky_numpy.py plus the numpy branches of argument_generator / write_python_code / tricky_weird). It was extracted so the core generator carries no numpy-specific code.

Install

pip install -e .          # from a checkout, into the same venv as fusil

Requires fusil and numpy.

Use

Just install it — it activates automatically for every run:

PYTHONPATH=$PWD python fuzzers/fusil-python-threaded --force-unsafe --modules json

• --no-numpy turns it off for a run.
• --no-external-references suppresses the injected references (the setup is still emitted).
• Uninstall the plugin to remove numpy support entirely.

What it registers

Hook	Provided by
--no-numpy CLI option	opt-out, preserved from the core
add_argument_generator (simple + complex, weight 50)	reference to a random pre-built numpy_* object
add_definitions_provider	import numpy + the tricky-object setup source
declare_dependency("numpy")	advertises the numpy requirement

Layout

• fusil_numpy_plugin/__init__.py — register() and the thin adapters.
• fusil_numpy_plugin/tricky_numpy.py — the pre-built tricky-object catalog (embedded verbatim).