Fuzzing support for Python projects? #4121
Description
I'm a core developer of Hypothesis, the property-based testing library for Python. Hypothesis is secretly a structured fuzzer, and in March I added support for treating arbitrary property-based tests as fuzz targets.
It would be lovely to apply this toolchain to CPython (see here, and here), write fuzzable tests for pip, fuzz existing tests for foundational tools like Numpy/Mercurial/PyPy, and so on. The only catch is that it's unclear to me whether, and if so how, Python projects are actually supported in OSS-FUZZ!
For example, to exercise the Python JSON module with python-afl:
import json, os, sys
import afl
from hypothesis import given, strategies as st
@given(st.recursive(
st.none() | st.booleans() | st.integers() | st.floats(allow_nan=False) | st.text(),
lambda x: st.lists(x) | st.dictionaries(st.text(), x)
))
def test_json_rountrip(x):
assert x == json.loads(json.dumps(x))
if __name__ == "__main__":
fuzz_target = test_json_rountrip.hypothesis.fuzz_one_input
afl.init()
fuzz_target(sys.stdin.buffer)
os._exit(0)If upstream support in Hypothesis would make OSS-FUZZ integration easier, I would be very happy to add whatever interface we decide on 🙂