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SystemError in OpenSSL's SHAKE when passing negative digest sizes #135759
Description
Bug report
Bug description:
import _hashlib
_hashlib.openssl_shake_128(b'').digest(-1) # SystemError
_hashlib.openssl_shake_128(b'').hexdigest(-1) # MemoryError
import _sha3
_sha3.shake_128(b'').digest(-1) # ValueError
_sha3.shake_128(b'').hexdigest(-1) # ValueErrorThe reason is that OpenSSL implementation accepts a ssize_t but HACL* accepts a uint32_t. I suggest raising a ValueError in OpenSSL's implementation as well. I'll rewrite #135744 for this issue at the same time.
Now, to prevent users passing incorrect data length, I also suggest to restrict has lengths to 2 ** 29 as it was done in HACL* and in #79103 but I'll do it in a follow-up. In the first time, let's only focus on raising a ValueError for all implementations on negative inputs.
CPython versions tested on:
CPython main branch
Operating systems tested on:
No response
Linked PRs
Note
See #135759 (comment) for the rationale of a non-backport.
Activity
picnixz commentedon Jun 20, 2025
I'm not going to backport this as this changes error messages and exception types. AFAIK, there is no crash, just weird exception types.
gh-135759: consistently reject negative sizes in SHAKE digests (#135767)
pythongh-135759: consistently reject negative sizes in SHAKE digests (p…
pythongh-135759: consistently reject negative sizes in SHAKE digests (p…
pythongh-135759: consistently reject negative sizes in SHAKE digests (p…