diff options
| -rw-r--r-- | cryptography/exceptions.py | 15 | ||||
| -rw-r--r-- | cryptography/hazmat/bindings/openssl/backend.py | 10 | ||||
| -rw-r--r-- | docs/exceptions.rst | 9 | ||||
| -rw-r--r-- | docs/hazmat/primitives/symmetric-encryption.rst | 9 | ||||
| -rw-r--r-- | docs/index.rst | 1 | ||||
| -rw-r--r-- | tests/hazmat/primitives/test_block.py | 11 |
6 files changed, 52 insertions, 3 deletions
diff --git a/cryptography/exceptions.py b/cryptography/exceptions.py new file mode 100644 index 00000000..1821ceb7 --- /dev/null +++ b/cryptography/exceptions.py @@ -0,0 +1,15 @@ +# Licensed under the Apache License, Version 2.0 (the "License"); +# you may not use this file except in compliance with the License. +# You may obtain a copy of the License at +# +# http://www.apache.org/licenses/LICENSE-2.0 +# +# Unless required by applicable law or agreed to in writing, software +# distributed under the License is distributed on an "AS IS" BASIS, +# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or +# implied. +# See the License for the specific language governing permissions and +# limitations under the License. + +class NoSuchAlgorithm(Exception): + pass diff --git a/cryptography/hazmat/bindings/openssl/backend.py b/cryptography/hazmat/bindings/openssl/backend.py index fc73dd39..ce8c6a55 100644 --- a/cryptography/hazmat/bindings/openssl/backend.py +++ b/cryptography/hazmat/bindings/openssl/backend.py @@ -18,6 +18,7 @@ import sys import cffi +from cryptography.exceptions import NoSuchAlgorithm from cryptography.hazmat.primitives import interfaces from cryptography.hazmat.primitives.block.ciphers import ( AES, Blowfish, Camellia, CAST5, TripleDES, @@ -128,9 +129,12 @@ class _CipherContext(object): ctx = self._backend.ffi.gc(ctx, self._backend.lib.EVP_CIPHER_CTX_free) registry = self._backend.ciphers._cipher_registry - evp_cipher = registry[type(cipher), type(mode)]( - self._backend, cipher, mode - ) + try: + adapter = registry[type(cipher), type(mode)] + except KeyError: + raise NoSuchAlgorithm + + evp_cipher = adapter(self._backend, cipher, mode) assert evp_cipher != self._backend.ffi.NULL if isinstance(mode, interfaces.ModeWithInitializationVector): iv_nonce = mode.initialization_vector diff --git a/docs/exceptions.rst b/docs/exceptions.rst new file mode 100644 index 00000000..b391e620 --- /dev/null +++ b/docs/exceptions.rst @@ -0,0 +1,9 @@ +Exceptions +========== + +.. currentmodule:: cryptography.exceptions + +.. class:: NoSuchAlgorithm + + This is raised when a backend doesn't support the requested algorithm (or + combination of algorithms). diff --git a/docs/hazmat/primitives/symmetric-encryption.rst b/docs/hazmat/primitives/symmetric-encryption.rst index b8b1c839..48bad928 100644 --- a/docs/hazmat/primitives/symmetric-encryption.rst +++ b/docs/hazmat/primitives/symmetric-encryption.rst @@ -42,12 +42,21 @@ where the encrypter and decrypter both use the same key. :class:`~cryptography.hazmat.primitives.interfaces.CipherContext` provider. + If the backend doesn't support the requested combination of ``cipher`` + and ``mode`` a :class:`cryptography.exceptions.NoSuchAlgorithm` will + be raised. + .. method:: decryptor() :return: A decrypting :class:`~cryptography.hazmat.primitives.interfaces.CipherContext` provider. + If the backend doesn't support the requested combination of ``cipher`` + and ``mode`` a :class:`cryptography.exceptions.NoSuchAlgorithm` will + be raised. + + .. currentmodule:: cryptography.hazmat.primitives.interfaces .. class:: CipherContext diff --git a/docs/index.rst b/docs/index.rst index 4fd5d3be..eb30b5dd 100644 --- a/docs/index.rst +++ b/docs/index.rst @@ -31,6 +31,7 @@ Contents :maxdepth: 2 architecture + exceptions contributing security community diff --git a/tests/hazmat/primitives/test_block.py b/tests/hazmat/primitives/test_block.py index e0ed6697..2c0be1b5 100644 --- a/tests/hazmat/primitives/test_block.py +++ b/tests/hazmat/primitives/test_block.py @@ -17,6 +17,7 @@ import binascii import pytest +from cryptography.exceptions import NoSuchAlgorithm from cryptography.hazmat.primitives import interfaces from cryptography.hazmat.primitives.block import BlockCipher, ciphers, modes @@ -84,3 +85,13 @@ class TestBlockCipherContext(object): assert len(pt) == 80 assert pt == b"a" * 80 decryptor.finalize() + + def test_nonexistant_cipher(self, backend): + cipher = BlockCipher( + object(), object(), backend + ) + with pytest.raises(NoSuchAlgorithm): + cipher.encryptor() + + with pytest.raises(NoSuchAlgorithm): + cipher.decryptor() |