diff options
| -rw-r--r-- | src/cryptography/hazmat/backends/multibackend.py | 7 | ||||
| -rw-r--r-- | tests/hazmat/backends/test_multibackend.py | 20 |
2 files changed, 22 insertions, 5 deletions
diff --git a/src/cryptography/hazmat/backends/multibackend.py b/src/cryptography/hazmat/backends/multibackend.py index 65f18531..48bc7d08 100644 --- a/src/cryptography/hazmat/backends/multibackend.py +++ b/src/cryptography/hazmat/backends/multibackend.py @@ -28,6 +28,13 @@ class MultiBackend(object): name = "multibackend" def __init__(self, backends): + if len(backends) == 0: + raise ValueError( + "Multibackend cannot be initialized with no backends. If you " + "are seeing this error when trying to use default_backend() " + "please try uninstalling and reinstalling cryptography." + ) + self._backends = backends def _filtered_backends(self, interface): diff --git a/tests/hazmat/backends/test_multibackend.py b/tests/hazmat/backends/test_multibackend.py index 74835716..bf54d5ce 100644 --- a/tests/hazmat/backends/test_multibackend.py +++ b/tests/hazmat/backends/test_multibackend.py @@ -4,6 +4,8 @@ from __future__ import absolute_import, division, print_function +import pytest + from cryptography import utils from cryptography.exceptions import ( UnsupportedAlgorithm, _Reasons @@ -21,6 +23,10 @@ from cryptography.hazmat.primitives.ciphers import Cipher, algorithms, modes from ...utils import raises_unsupported_algorithm +class DummyBackend(object): + pass + + @utils.register_interface(CipherBackend) class DummyCipherBackend(object): def __init__(self, supported_ciphers): @@ -226,6 +232,10 @@ class DummyX509Backend(object): class TestMultiBackend(object): + def test_raises_error_with_empty_list(self): + with pytest.raises(ValueError): + MultiBackend([]) + def test_ciphers(self): backend = MultiBackend([ DummyHashBackend([]), @@ -310,7 +320,7 @@ class TestMultiBackend(object): backend.load_rsa_public_numbers("public_numbers") - backend = MultiBackend([]) + backend = MultiBackend([DummyBackend()]) with raises_unsupported_algorithm( _Reasons.UNSUPPORTED_PUBLIC_KEY_ALGORITHM ): @@ -353,7 +363,7 @@ class TestMultiBackend(object): backend.load_dsa_public_numbers("numbers") backend.load_dsa_parameter_numbers("numbers") - backend = MultiBackend([]) + backend = MultiBackend([DummyBackend()]) with raises_unsupported_algorithm( _Reasons.UNSUPPORTED_PUBLIC_KEY_ALGORITHM ): @@ -491,7 +501,7 @@ class TestMultiBackend(object): backend.load_pem_private_key(b"keydata", None) backend.load_pem_public_key(b"keydata") - backend = MultiBackend([]) + backend = MultiBackend([DummyBackend()]) with raises_unsupported_algorithm(_Reasons.UNSUPPORTED_SERIALIZATION): backend.load_pem_private_key(b"keydata", None) with raises_unsupported_algorithm(_Reasons.UNSUPPORTED_SERIALIZATION): @@ -503,7 +513,7 @@ class TestMultiBackend(object): backend.load_der_private_key(b"keydata", None) backend.load_der_public_key(b"keydata") - backend = MultiBackend([]) + backend = MultiBackend([DummyBackend()]) with raises_unsupported_algorithm(_Reasons.UNSUPPORTED_SERIALIZATION): backend.load_der_private_key(b"keydata", None) with raises_unsupported_algorithm(_Reasons.UNSUPPORTED_SERIALIZATION): @@ -523,7 +533,7 @@ class TestMultiBackend(object): backend.create_x509_crl(object(), b"privatekey", hashes.SHA1()) backend.create_x509_revoked_certificate(object()) - backend = MultiBackend([]) + backend = MultiBackend([DummyBackend()]) with raises_unsupported_algorithm(_Reasons.UNSUPPORTED_X509): backend.load_pem_x509_certificate(b"certdata") with raises_unsupported_algorithm(_Reasons.UNSUPPORTED_X509): |