Usage of RAND_bytes breaks with cryptography>=45.0

[mweinelt]

With python-jose 3.4.0 and cryptography 45.0.1 I encounter the following error when running the test suite. Versions of cryptography before 45.0 are fine.

The relevant change is in here: pyca/cryptography@fc00112

python-jose> num_bytes = 64
python-jose> 
python-jose>     def get_random_bytes(num_bytes):
python-jose>         """
python-jose>         Get random bytes
python-jose>     
python-jose>         Currently, Cryptography returns OS random bytes. If you want OpenSSL
python-jose>         generated random bytes, you'll have to switch the RAND engine after
python-jose>         initializing the OpenSSL backend
python-jose>         Args:
python-jose>             num_bytes (int): Number of random bytes to generate and return
python-jose>         Returns:
python-jose>             bytes: Random bytes
python-jose>         """
python-jose>         global _binding
python-jose>     
python-jose>         if _binding is None:
python-jose>             _binding = Binding()
python-jose>     
python-jose>         buf = _binding.ffi.new("char[]", num_bytes)
python-jose> >       _binding.lib.RAND_bytes(buf, num_bytes)
python-jose> E       AttributeError: module 'lib' has no attribute 'RAND_bytes'. Did you mean: 'RAND_status'?
python-jose> 
python-jose> jose/backends/cryptography_backend.py:51: AttributeError

[mzealey]

Yes this has just hit us and I suspect a lot more people will be getting it shortly.

[isotopes-gopal]

Hit this issue, which is thankfully monkey-patchable.

@pytest.fixture(autouse=True)
def monkey_patch_jose():
    import os
    from jose import backends
    
    old_get_random_bytes = backends.cryptography_backend.get_random_bytes
    backends.cryptography_backend.get_random_bytes = lambda n : bytes(os.urandom(n))
    # monkey patch the get_random_bytes function to use os.urandom
    yield
    backends.cryptography_backend.get_random_bytes = old_get_random_bytes

Seems to fix my JWE tests right now