diff options
-rw-r--r-- | cryptography/hazmat/backends/commoncrypto/hmac.py | 13 | ||||
-rw-r--r-- | cryptography/hazmat/backends/openssl/cmac.py | 13 | ||||
-rw-r--r-- | cryptography/hazmat/backends/openssl/hmac.py | 13 | ||||
-rw-r--r-- | cryptography/utils.py | 27 | ||||
-rw-r--r-- | tests/hazmat/primitives/test_ec.py | 1 | ||||
-rw-r--r-- | tests/test_interfaces.py | 63 |
6 files changed, 123 insertions, 7 deletions
diff --git a/cryptography/hazmat/backends/commoncrypto/hmac.py b/cryptography/hazmat/backends/commoncrypto/hmac.py index c2b6c379..b4c7cc3c 100644 --- a/cryptography/hazmat/backends/commoncrypto/hmac.py +++ b/cryptography/hazmat/backends/commoncrypto/hmac.py @@ -14,8 +14,10 @@ from __future__ import absolute_import, division, print_function from cryptography import utils -from cryptography.exceptions import UnsupportedAlgorithm, _Reasons -from cryptography.hazmat.primitives import interfaces +from cryptography.exceptions import ( + InvalidSignature, UnsupportedAlgorithm, _Reasons +) +from cryptography.hazmat.primitives import constant_time, interfaces @utils.register_interface(interfaces.MACContext) @@ -59,3 +61,10 @@ class _HMACContext(object): self.algorithm.digest_size) self._backend._lib.CCHmacFinal(self._ctx, buf) return self._backend._ffi.buffer(buf)[:] + + def verify(self, signature): + if not isinstance(signature, bytes): + raise TypeError("signature must be bytes.") + digest = self.finalize() + if not constant_time.bytes_eq(digest, signature): + raise InvalidSignature("Signature did not match digest.") diff --git a/cryptography/hazmat/backends/openssl/cmac.py b/cryptography/hazmat/backends/openssl/cmac.py index 6a844cdc..113188ca 100644 --- a/cryptography/hazmat/backends/openssl/cmac.py +++ b/cryptography/hazmat/backends/openssl/cmac.py @@ -15,8 +15,10 @@ from __future__ import absolute_import, division, print_function from cryptography import utils -from cryptography.exceptions import UnsupportedAlgorithm, _Reasons -from cryptography.hazmat.primitives import interfaces +from cryptography.exceptions import ( + InvalidSignature, UnsupportedAlgorithm, _Reasons +) +from cryptography.hazmat.primitives import constant_time, interfaces from cryptography.hazmat.primitives.ciphers.modes import CBC @@ -80,3 +82,10 @@ class _CMACContext(object): return _CMACContext( self._backend, self._algorithm, ctx=copied_ctx ) + + def verify(self, signature): + if not isinstance(signature, bytes): + raise TypeError("signature must be bytes.") + digest = self.finalize() + if not constant_time.bytes_eq(digest, signature): + raise InvalidSignature("Signature did not match digest.") diff --git a/cryptography/hazmat/backends/openssl/hmac.py b/cryptography/hazmat/backends/openssl/hmac.py index d5300ea0..07babbf9 100644 --- a/cryptography/hazmat/backends/openssl/hmac.py +++ b/cryptography/hazmat/backends/openssl/hmac.py @@ -15,8 +15,10 @@ from __future__ import absolute_import, division, print_function from cryptography import utils -from cryptography.exceptions import UnsupportedAlgorithm, _Reasons -from cryptography.hazmat.primitives import interfaces +from cryptography.exceptions import ( + InvalidSignature, UnsupportedAlgorithm, _Reasons +) +from cryptography.hazmat.primitives import constant_time, interfaces @utils.register_interface(interfaces.MACContext) @@ -81,3 +83,10 @@ class _HMACContext(object): assert outlen[0] == self.algorithm.digest_size self._backend._lib.HMAC_CTX_cleanup(self._ctx) return self._backend._ffi.buffer(buf)[:outlen[0]] + + def verify(self, signature): + if not isinstance(signature, bytes): + raise TypeError("signature must be bytes.") + digest = self.finalize() + if not constant_time.bytes_eq(digest, signature): + raise InvalidSignature("Signature did not match digest.") diff --git a/cryptography/utils.py b/cryptography/utils.py index 1deb3d1d..03c8c0e8 100644 --- a/cryptography/utils.py +++ b/cryptography/utils.py @@ -13,6 +13,8 @@ from __future__ import absolute_import, division, print_function +import abc +import inspect import sys @@ -21,6 +23,7 @@ DeprecatedIn06 = DeprecationWarning def register_interface(iface): def register_decorator(klass): + verify_interface(iface, klass) iface.register(klass) return klass return register_decorator @@ -30,6 +33,30 @@ def read_only_property(name): return property(lambda self: getattr(self, name)) +class InterfaceNotImplemented(Exception): + pass + + +def verify_interface(iface, klass): + for method in iface.__abstractmethods__: + if not hasattr(klass, method): + raise InterfaceNotImplemented( + "{0} is missing a {1!r} method".format(klass, method) + ) + if isinstance(getattr(iface, method), abc.abstractproperty): + # Can't properly verify these yet. + continue + spec = inspect.getargspec(getattr(iface, method)) + actual = inspect.getargspec(getattr(klass, method)) + if spec != actual: + raise InterfaceNotImplemented( + "{0}.{1}'s signature differs from the expected. Expected: " + "{2!r}. Received: {3!r}".format( + klass, method, spec, actual + ) + ) + + def bit_length(x): if sys.version_info >= (2, 7): return x.bit_length() diff --git a/tests/hazmat/primitives/test_ec.py b/tests/hazmat/primitives/test_ec.py index e6a9146c..6aea58a5 100644 --- a/tests/hazmat/primitives/test_ec.py +++ b/tests/hazmat/primitives/test_ec.py @@ -71,7 +71,6 @@ class DummySignatureAlgorithm(object): algorithm = None -@utils.register_interface(EllipticCurveBackend) class DeprecatedDummyECBackend(object): def elliptic_curve_private_key_from_numbers(self, numbers): return b"private_key" diff --git a/tests/test_interfaces.py b/tests/test_interfaces.py new file mode 100644 index 00000000..b988abee --- /dev/null +++ b/tests/test_interfaces.py @@ -0,0 +1,63 @@ +# 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. + +import abc + +import pytest + +import six + +from cryptography.utils import InterfaceNotImplemented, verify_interface + + +class TestVerifyInterface(object): + def test_verify_missing_method(self): + @six.add_metaclass(abc.ABCMeta) + class SimpleInterface(object): + @abc.abstractmethod + def method(self): + """A simple method""" + + class NonImplementer(object): + pass + + with pytest.raises(InterfaceNotImplemented): + verify_interface(SimpleInterface, NonImplementer) + + def test_different_arguments(self): + @six.add_metaclass(abc.ABCMeta) + class SimpleInterface(object): + @abc.abstractmethod + def method(self, a): + """Method with one argument""" + + class NonImplementer(object): + def method(self): + """Method with no arguments""" + + with pytest.raises(InterfaceNotImplemented): + verify_interface(SimpleInterface, NonImplementer) + + def test_handles_abstract_property(self): + @six.add_metaclass(abc.ABCMeta) + class SimpleInterface(object): + @abc.abstractproperty + def property(self): + """An abstract property""" + + class NonImplementer(object): + @property + def property(self): + """A concrete property""" + + verify_interface(SimpleInterface, NonImplementer) |