diff options
| -rw-r--r-- | cryptography/hazmat/backends/multibackend.py | 35 | ||||
| -rw-r--r-- | tests/hazmat/backends/test_multibackend.py | 10 |
2 files changed, 35 insertions, 10 deletions
diff --git a/cryptography/hazmat/backends/multibackend.py b/cryptography/hazmat/backends/multibackend.py index e560c7df..94152370 100644 --- a/cryptography/hazmat/backends/multibackend.py +++ b/cryptography/hazmat/backends/multibackend.py @@ -30,11 +30,19 @@ class PrioritizedMultiBackend(object): def __init__(self, backends): self._backends = backends + def _filtered_backends(self, interface): + for b in self._backends: + if isinstance(b, interface): + yield b + def cipher_supported(self, algorithm, mode): - return any(b.cipher_supported(algorithm, mode) for b in self._backends) + return any( + b.cipher_supported(algorithm, mode) + for b in self._filtered_backends(CipherBackend) + ) def create_symmetric_encryption_ctx(self, algorithm, mode): - for b in self._backends: + for b in self._filtered_backends(CipherBackend): try: return b.create_symmetric_encryption_ctx(algorithm, mode) except UnsupportedAlgorithm: @@ -42,7 +50,7 @@ class PrioritizedMultiBackend(object): raise UnsupportedAlgorithm def create_symmetric_decryption_ctx(self, algorithm, mode): - for b in self._backends: + for b in self._filtered_backends(CipherBackend): try: return b.create_symmetric_decryption_ctx(algorithm, mode) except UnsupportedAlgorithm: @@ -50,10 +58,13 @@ class PrioritizedMultiBackend(object): raise UnsupportedAlgorithm def hash_supported(self, algorithm): - return any(b.hash_supported(algorithm) for b in self._backends) + return any( + b.hash_supported(algorithm) + for b in self._filtered_backends(HashBackend) + ) def create_hash_ctx(self, algorithm): - for b in self._backends: + for b in self._filtered_backends(HashBackend): try: return b.create_hash_ctx(algorithm) except UnsupportedAlgorithm: @@ -61,10 +72,13 @@ class PrioritizedMultiBackend(object): raise UnsupportedAlgorithm def hmac_supported(self, algorithm): - return any(b.hmac_supported(algorithm) for b in self._backends) + return any( + b.hmac_supported(algorithm) + for b in self._filtered_backends(HMACBackend) + ) def create_hmac_ctx(self, key, algorithm): - for b in self._backends: + for b in self._filtered_backends(HMACBackend): try: return b.create_hmac_ctx(key, algorithm) except UnsupportedAlgorithm: @@ -72,11 +86,14 @@ class PrioritizedMultiBackend(object): raise UnsupportedAlgorithm def pbkdf2_hmac_supported(self, algorithm): - return any(b.pbkdf2_hmac_supported(algorithm) for b in self._backends) + return any( + b.pbkdf2_hmac_supported(algorithm) + for b in self._filtered_backends(PBKDF2HMACBackend) + ) def derive_pbkdf2_hmac(self, algorithm, length, salt, iterations, key_material): - for b in self._backends: + for b in self._filtered_backends(PBKDF2HMACBackend): try: return b.derive_pbkdf2_hmac( algorithm, length, salt, iterations, key_material diff --git a/tests/hazmat/backends/test_multibackend.py b/tests/hazmat/backends/test_multibackend.py index 03b3187b..127c0d3e 100644 --- a/tests/hazmat/backends/test_multibackend.py +++ b/tests/hazmat/backends/test_multibackend.py @@ -13,13 +13,17 @@ import pytest +from cryptography import utils from cryptography.exceptions import UnsupportedAlgorithm +from cryptography.hazmat.backends.interfaces import ( + CipherBackend, HashBackend, HMACBackend, PBKDF2HMACBackend +) from cryptography.hazmat.backends.multibackend import PrioritizedMultiBackend from cryptography.hazmat.primitives import hashes, hmac from cryptography.hazmat.primitives.ciphers import Cipher, algorithms, modes -from cryptography.hazmat.primitives.kdf.pbkdf2 import PBKDF2HMAC +@utils.register_interface(CipherBackend) class DummyCipherBackend(object): def __init__(self, supported_ciphers): self._ciphers = supported_ciphers @@ -36,6 +40,7 @@ class DummyCipherBackend(object): raise UnsupportedAlgorithm +@utils.register_interface(HashBackend) class DummyHashBackend(object): def __init__(self, supported_algorithms): self._algorithms = supported_algorithms @@ -48,6 +53,7 @@ class DummyHashBackend(object): raise UnsupportedAlgorithm +@utils.register_interface(HMACBackend) class DummyHMACBackend(object): def __init__(self, supported_algorithms): self._algorithms = supported_algorithms @@ -60,6 +66,7 @@ class DummyHMACBackend(object): raise UnsupportedAlgorithm +@utils.register_interface(PBKDF2HMACBackend) class DummyPBKDF2HMAC(object): def __init__(self, supported_algorithms): self._algorithms = supported_algorithms @@ -77,6 +84,7 @@ class DummyPBKDF2HMAC(object): class TestPrioritizedMultiBackend(object): def test_ciphers(self): backend = PrioritizedMultiBackend([ + DummyHashBackend([]), DummyCipherBackend([ (algorithms.AES, modes.CBC), ]) |