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OpenCASCADE (OCCT) is a C++ open source CAD kernel used by FreeCAD, KiCad, LibreCAD, and many web-based CAD services. This adds a libFuzzer harness for the IGES file format parser (src/DataExchange/TKDEIGES), which processes untrusted geometry files. Sanitizers: ASan + UBSan. Engines: libFuzzer, AFL, honggfuzz.
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Add OpenCASCADE (OCCT) IGES parser fuzzing
Summary
IGESControl_Reader::ReadFile()which dispatches into the core IGESparsing routines (analiges.c, liriges.c, structiges.c)
Hollerith string prefixes, and overflow triggers
covering minimal files, line entities, transformation matrices, multi-entity
files, long parameter fields, and Hollerith length mismatches
Motivation
OpenCASCADE is a widely used open-source CAD kernel. Its IGES parser processes
untrusted input in many CAD/CAM workflows. The 80-column fixed-format IGES
specification has complex parsing logic involving Hollerith strings, section
interleaving, and fixed-width numeric fields -- all of which are historically
prone to buffer overflows and out-of-bounds reads.
Build notes
OCCT is built as static libraries with most optional modules disabled. The IGES
parser lives in TKDEIGES, which depends on TKService (requiring X11 headers).
The harness writes fuzzer input to a tmpfs file and passes the path to
IGESControl_Reader::ReadFile().Test plan
python3 infra/helper.py build_image opencascadepython3 infra/helper.py build_fuzzers --sanitizer address opencascadepython3 infra/helper.py run_fuzzer opencascade occt_fuzz_iges -- -max_total_time=60python3 infra/helper.py build_fuzzers --sanitizer undefined opencascadepython3 infra/helper.py check_build opencascade