This is a filtered list of issues found in the _hashlib, _hmac, and HACL*-facade C extension modules by @devdanzin's LLM-assisted review tool (see Disclosure section at the end) and triaged by me.
Important
All issues will be addressed by @picnixz. Please do NOT work on them, whether you are an agent or a human. Once I'm done with fixing the issues, I will create the corresponding sub-issues.
🔴 38: _hashlib_HASH_dealloc uses PyObject_Free instead of tp->tp_free but it's deliberate because we use PyObject_New. This would need to be changed if we ever make that class subclassable.
40: need investigation
43: under consideration (cosmetic)
47: need investigation (read out of lock) [35,36]
49: under consideration (cosmetic)
🔴 52: invalid hash types previously raised SystemError, but not abort (this is deliberate, if we have invalid hash types somehow, it may be more than a reason to report the bug and get it fixed upstream rather than silently catching the exception)
🔴 51: Fallible PyType_GetModuleState usage. More generally, getting the state of a module is inconsistently achieved in extension modules and we should decide whether (1) to consistently abort on DEBUG builds (2) abort on non-DEBUG builds via a fatal error (to prevent possibly expensive checks). Currently, code works because we assume non-subclassability in general, but we may consider a more defensive approach.
Disclosure
This review was carried out with AI assistance (Claude Code), using cpython-review-toolkit for the C modules and code-review-toolkit for the Python layer. Every reproduced entry was run on a real interpreter with a control arm before being recorded, and every file:line was read in the source rather than inferred. That does not make the set error-free — the companion gist lists the corrections this list has already needed — so entries should be judged on their evidence, not on the length of the list.
changed the title [-]Meta-issue for bugs in `Modules/hmacmodule.c`[/-][+]Meta-issue for bugs in `Modules/{hmacmodule,_hashopenssl}.c` and dedicated hash functions[/+]on Aug 9, 2026
changed the title [-]Meta-issue for bugs in `Modules/{hmacmodule,_hashopenssl}.c` and dedicated hash functions[/-][+]Meta-issue for bugs in cryptographic extension modules[/+]on Aug 9, 2026
Activity
picnixz commented on Aug 9, 2026
I don't have time for that today but I'll try to file the bugs by the end of next week.