Replaced an assertion in the OpenSSL backend with a proper exception
diff --git a/cryptography/hazmat/bindings/openssl/backend.py b/cryptography/hazmat/bindings/openssl/backend.py
index 32adfed..b610caa 100644
--- a/cryptography/hazmat/bindings/openssl/backend.py
+++ b/cryptography/hazmat/bindings/openssl/backend.py
@@ -135,7 +135,9 @@
raise UnsupportedAlgorithm
evp_cipher = adapter(self._backend, cipher, mode)
- assert evp_cipher != self._backend.ffi.NULL
+ if evp_cipher == self._backend.ffi.NULL:
+ raise UnsupportedAlgorithm
+
if isinstance(mode, interfaces.ModeWithInitializationVector):
iv_nonce = mode.initialization_vector
elif isinstance(mode, interfaces.ModeWithNonce):
diff --git a/tests/hazmat/bindings/test_openssl.py b/tests/hazmat/bindings/test_openssl.py
index 9ce882e..fcd54dd 100644
--- a/tests/hazmat/bindings/test_openssl.py
+++ b/tests/hazmat/bindings/test_openssl.py
@@ -11,11 +11,15 @@
# See the License for the specific language governing permissions and
# limitations under the License.
+import binascii
+
import pytest
-from cryptography.hazmat.bindings.openssl.backend import backend
-from cryptography.hazmat.primitives.block.ciphers import AES
-from cryptography.hazmat.primitives.block.modes import CBC
+from cryptography.exceptions import UnsupportedAlgorithm
+from cryptography.hazmat.bindings.openssl.backend import backend, Backend
+from cryptography.hazmat.primitives.block import BlockCipher
+from cryptography.hazmat.primitives.block.ciphers import AES, TripleDES
+from cryptography.hazmat.primitives.block.modes import CBC, ECB
class TestOpenSSL(object):
@@ -39,3 +43,15 @@
def test_register_duplicate_cipher_adapter(self):
with pytest.raises(ValueError):
backend.ciphers.register_cipher_adapter(AES, CBC, None)
+
+ def test_nonexistant_cipher(self):
+ b = Backend()
+ # TODO: this test assumes that 3DES-ECB doesn't exist
+ b.ciphers.register_cipher_adapter(
+ TripleDES, ECB, lambda backend, cipher, mode: backend.ffi.NULL
+ )
+ cipher = BlockCipher(
+ TripleDES(binascii.unhexlify(b"0" * 16)), ECB(), backend=b
+ )
+ with pytest.raises(UnsupportedAlgorithm):
+ cipher.encryptor()