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P1sec / pycrate

A Python library to ease the development of encoders and decoders for various protocols and file formats; contains ASN.1 and CSN.1 compilers.
GNU Lesser General Public License v2.1
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Adds one fuzz target for fuzz testing #69

Closed catenacyber closed 4 years ago

catenacyber commented 4 years ago

This PR is a draft for discussion

cc @H21lab cf https://github.com/P1sec/pycrate/blob/master/test/test_tcapmap.py#L75 cc @yevgenypats for usage of python-fuzz https://github.com/fuzzitdev/pythonfuzz

The big question is where (and which) exceptions should be handled (in the library or in the application)

More targets can easily be written.

p1-bmu commented 4 years ago

Thanks for the submission. I was not aware of this handy fuzzer: quite simple to use and looking efficient.

Regarding exception handling within the ASN.1 runtime, some errors are caught by pycrate, some errors happen within the Python runtime. I am not willing to catch and re-emit all proper Python runtime exceptions that could happen. On the other side, I realize there are many assert() (from the initial release) that should now be moved to proper exception handling. I have to check that carefully, because there are (too) many of them (around 60)...

In case you are willing to help, you are welcome. Thanks.

p1-bmu commented 4 years ago

I modified slightly the fuzz testing done here: https://github.com/P1sec/pycrate/blob/master/test/fuzz/fuzz_asn1rt.py. It found some uncaught Exception or assert, what led to some fixes commited into the ASN.1 runtime.