Bug 2293080

python-cryptography fails to build with Python 3.13 in Fedora Rawhide (41) on i686.

Build failure:

_______________________ TestFixedPool.test_thread_stress _______________________
self = <tests.test_rust_utils.TestFixedPool object at 0xf5db5a08>
    def test_thread_stress(self):
        def create():
            return None
    
        pool = FixedPool(create)
    
        def thread_fn():
            with pool.acquire():
                pass
    
        threads = []
        for i in range(1024):
            t = threading.Thread(target=thread_fn)
>           t.start()
tests/test_rust_utils.py:59: 
_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ 
self = <Thread(Thread-501 (thread_fn), stopped)>
    def start(self):
        """Start the thread's activity.
    
        It must be called at most once per thread object. It arranges for the
        object's run() method to be invoked in a separate thread of control.
    
        This method will raise a RuntimeError if called more than once on the
        same thread object.
    
        """
        if not self._initialized:
            raise RuntimeError("thread.__init__() not called")
    
        if self._started.is_set():
            raise RuntimeError("threads can only be started once")
    
        with _active_limbo_lock:
            _limbo[self] = self
        try:
            # Start joinable thread
>           _start_joinable_thread(self._bootstrap, handle=self._handle,
                                   daemon=self.daemon)
E                                  RuntimeError: can't start new thread
/usr/lib/python3.13/threading.py:971: RuntimeError
_______________________ TestScrypt.test_derive[params2] ________________________
self = <tests.hazmat.primitives.test_scrypt.TestScrypt object at 0xf576e228>
backend = <OpenSSLBackend(version: OpenSSL 3.2.2 4 Jun 2024, FIPS: False, Legacy: True)>
params = {'derived_key': b'7023bdcb3afd7348461c06cd81fd38ebfda8fbba904f8e3ea9b543f6545da1f2d5432955613f0fcf62d49705242a9af9e61e85dc0d651e40dfcf017b45575887', 'length': b'64', 'n': b'16384', 'p': b'1', ...}
    @pytest.mark.parametrize("params", vectors)
    def test_derive(self, backend, params):
        _skip_if_memory_limited(_MEM_LIMIT, params)
        password = params["password"]
        work_factor = int(params["n"])
        block_size = int(params["r"])
        parallelization_factor = int(params["p"])
        length = int(params["length"])
        salt = params["salt"]
        derived_key = params["derived_key"]
    
        scrypt = Scrypt(
            salt,
            length,
            work_factor,
            block_size,
            parallelization_factor,
            backend,
        )
>       assert binascii.hexlify(scrypt.derive(password)) == derived_key
tests/hazmat/primitives/test_scrypt.py:80: 
_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ 
self = <cryptography.hazmat.primitives.kdf.scrypt.Scrypt object at 0xf52eddf8>
key_material = b'pleaseletmein'
    def derive(self, key_material: bytes) -> bytes:
        if self._used:
            raise AlreadyFinalized("Scrypt instances can only be used once.")
        self._used = True
    
        utils._check_byteslike("key_material", key_material)
    
>       return rust_openssl.kdf.derive_scrypt(
            key_material,
            self._salt,
            self._n,
            self._r,
            self._p,
            _MEM_LIMIT,
            self._length,
        )
E       MemoryError: Not enough memory to derive key. These parameters require 16MB of memory.
../BUILDROOT/usr/lib/python3.13/site-packages/cryptography/hazmat/primitives/kdf/scrypt.py:67: MemoryError
_______________________ TestScrypt.test_verify[params2] ________________________
self = <tests.hazmat.primitives.test_scrypt.TestScrypt object at 0xf5778030>
backend = <OpenSSLBackend(version: OpenSSL 3.2.2 4 Jun 2024, FIPS: False, Legacy: True)>
params = {'derived_key': b'7023bdcb3afd7348461c06cd81fd38ebfda8fbba904f8e3ea9b543f6545da1f2d5432955613f0fcf62d49705242a9af9e61e85dc0d651e40dfcf017b45575887', 'length': b'64', 'n': b'16384', 'p': b'1', ...}
    @pytest.mark.parametrize("params", vectors)
    def test_verify(self, backend, params):
        _skip_if_memory_limited(_MEM_LIMIT, params)
        password = params["password"]
        work_factor = int(params["n"])
        block_size = int(params["r"])
        parallelization_factor = int(params["p"])
        length = int(params["length"])
        salt = params["salt"]
        derived_key = params["derived_key"]
    
        scrypt = Scrypt(
            salt,
            length,
            work_factor,
            block_size,
            parallelization_factor,
            backend,
        )
>       scrypt.verify(password, binascii.unhexlify(derived_key))
tests/hazmat/primitives/test_scrypt.py:177: 
_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ 
../BUILDROOT/usr/lib/python3.13/site-packages/cryptography/hazmat/primitives/kdf/scrypt.py:78: in verify
    derived_key = self.derive(key_material)
_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ 
self = <cryptography.hazmat.primitives.kdf.scrypt.Scrypt object at 0xf5565250>
key_material = b'pleaseletmein'
    def derive(self, key_material: bytes) -> bytes:
        if self._used:
            raise AlreadyFinalized("Scrypt instances can only be used once.")
        self._used = True
    
        utils._check_byteslike("key_material", key_material)
    
>       return rust_openssl.kdf.derive_scrypt(
            key_material,
            self._salt,
            self._n,
            self._r,
            self._p,
            _MEM_LIMIT,
            self._length,
        )
E       MemoryError: Not enough memory to derive key. These parameters require 16MB of memory.
../BUILDROOT/usr/lib/python3.13/site-packages/cryptography/hazmat/primitives/kdf/scrypt.py:67: MemoryError

Let us know here if you have any questions.
Python 3.13 is planned to be included in Fedora 41.