Fixed issue aws#57. Discovered strange behavior with mocks not allowi…

…ng for

functions to be run without the mock being invoked (very confused).

Found issue with tox -e py37-manual and will seek to fix it in a future
set of commits.  Flake8 and linters SHOULD be passing after an autoformat
on this commit.

src/aws_encryption_sdk/internal/formatting/deserialize.py

@@ -29,6 +29,7 @@
 )
 from aws_encryption_sdk.internal.crypto.encryption import decrypt
 from aws_encryption_sdk.internal.defaults import MAX_FRAME_SIZE
+# necessary for it to call the correct deserialize_encryption_context
 from aws_encryption_sdk.internal.formatting.encryption_context import deserialize_encryption_context
 from aws_encryption_sdk.internal.str_ops import to_str
 from aws_encryption_sdk.internal.structures import (
@@ -242,6 +243,7 @@ def deserialize_header(stream):
     tee = io.BytesIO()
     tee_stream = TeeStream(stream, tee)
     version_id, message_type_id = unpack_values(">BB", tee_stream)
+
     header = dict()
     header["version"] = _verified_version_from_id(version_id)
     header["type"] = _verified_message_type_from_id(message_type_id)
@@ -251,7 +253,10 @@ def deserialize_header(stream):
     header["algorithm"] = _verified_algorithm_from_id(algorithm_id)
     header["message_id"] = message_id
 
-    header["encryption_context"] = deserialize_encryption_context(tee_stream.read(ser_encryption_context_length))
+    aad = tee_stream.read(ser_encryption_context_length)
+    # d_aad = aws_encryption_sdk.internal.formatting.encryption_context.deserialize_encryption_context(aad)
+    d_aad = deserialize_encryption_context(aad)
+    header["encryption_context"] = d_aad
 
     header["encrypted_data_keys"] = _deserialize_encrypted_data_keys(tee_stream)
 

src/aws_encryption_sdk/internal/formatting/encryption_context.py

@@ -139,20 +139,19 @@ def deserialize_encryption_context(serialized_encryption_context):
     :raises SerializationError: if duplicate key found in serialized encryption context
     :raises SerializationError: if malformed data found in serialized encryption context
     """
+    _LOGGER.debug("Deserializing Encryption Context")
     if len(serialized_encryption_context) > aws_encryption_sdk.internal.defaults.MAX_BYTE_ARRAY_SIZE:
         raise SerializationError("Serialized context is too long.")
-
     if serialized_encryption_context == b"":
         _LOGGER.debug("No encryption context data found")
         return {}
 
     deserialized_size = 0
     encryption_context = {}
-
     dict_size, deserialized_size = read_short(source=serialized_encryption_context, offset=deserialized_size)
     _LOGGER.debug("Found %d keys", dict_size)
 
-    # either the dict_size is just wrong, or this is malformed 
+    # either the dict_size is just wrong, or this is malformed
     # (and we assume the worst case and more common is the latter... former caught later)
     if dict_size == 0:
         raise SerializationError("Malformed AAD: zero length AAD with non-zero length AAD length field")

test/unit/test_deserialize.py

@@ -11,6 +11,7 @@
 # ANY KIND, either express or implied. See the License for the specific
 # language governing permissions and limitations under the License.
 """Unit test suite for aws_encryption_sdk.deserialize"""
+import base64
 import io
 import struct
 
@@ -72,7 +73,7 @@ def apply_fixtures(self):
         self.mock_decrypt = self.mock_decrypt_patcher.start()
         # Set up encryption_context patch
         self.mock_deserialize_ec_patcher = patch(
-            "aws_encryption_sdk.internal.formatting.deserialize.deserialize_encryption_context"
+            "aws_encryption_sdk.internal.formatting.encryption_context.deserialize_encryption_context"
         )
         self.mock_deserialize_ec = self.mock_deserialize_ec_patcher.start()
         self.mock_deserialize_ec.return_value = VALUES["updated_encryption_context"]
@@ -167,10 +168,31 @@ def test_deserialize_header_unknown_content_type(self):
             stream = io.BytesIO(VALUES["serialized_header_unknown_content_type"])
             aws_encryption_sdk.internal.formatting.deserialize.deserialize_header(stream)
         excinfo.match("Unknown content type *")
-
+
+    """
+    Decoded looks like this (with important incorrect AAD fields on their own lines):
+    b'\x01\x80\x00\x14\x9c\r\xf0\x88\x10\xf7\xed,\xc7,\xbb\xfb\xdd\x1c\x08(
+        \x00\x02
+        \x00\x00
+        \x00\x01\x00\x13WEB-CRYPTO-RSA-OAEP\x00(8CED2FD20FC88A9C06EFDB073707EB1EF1655780\x01
+        \x00V\xc8\x8b\xe8&J\xbb\xde\x8d\xf3\x82\x8d\xb14\xf2\xb4\xd8\x1f)\xb6\xb8\xb5\xac\x8a,\xd0\x1et\xf2
+        \xdf??U\xe4~\xec\xc2\xaf6\xfe\xd9|\xf7\xf9-~\xe2\xf5\xa9\x98\xc3\x10\x8c!+\xd8\xf8\x10\x9c\x9d\xd2
+        \xda\x90\x7f\xd1\x945\x1d\x83>\x7fCB\x80\xc6\xb19-~\xc3\x1f\x13\xbf\xc0\xcb\xe2$(\xbe\xa9u\x8co\xeen
+        \xd2hpz\x94b\x84\xef\xdd\x93\xed\xe4\x1a\xac\x9a.\x19\xc6\xb8\x0e\xb1\xa9\x89\x93\x85IBe\x1eA\xc1\xfc
+        \x84u\xd4\x9a\x9e\n;\xbaa\x16\xc3V\x10\xf2\xfa$\x8e\xa53\x08\xa4r\x93ui_\x04\x13]\x02\xcb\xac\x1c
+        \xfbff{\x02|\xe7\xd1*\x1a-\x89<\x0fJ\xcfZ\x12\x87\xbdE\xd0\x0c\x96\x03a\xd4;\xbe\x97\x9d\xc6\x9b\x04
+        \xe6\xf9b,\x8f|\x08\x07\x08ZYd\xb2\xdfz\xe02\x01\xc0\xa8\x00_\xa2\x1c\xf0\xd8\xfe\xf1>\xd5\xba\xb7J
+        \xd9!nL~\x0b"\xf9\x1ena\x06\x0b\x19\xe0u\x1a_\xa2\x91\x14\xfd\x17t-\x85\xd9\x8aN\x02\x00\x00\x00\x00
+        \x0c\x00\x00\x00\x06\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00+\xdb\xcdF\xfc\xa6\x0eJ1;\xa7r\xeb
+        \xbaC\xb9\xff\xff\xff\xff\x00\x00\x00\x01\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x01\x00\x00\x00
+        \x050*\x9a)P\xad\xa8\x13\x156\x1d?=\xb7\xc3SLG\xe7<S'
+    """
+
     def test_deserialize_header_malformed_aad(self):
-        malformed_header = io.BytesIO(b"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")
-        #malformed_header = io.BytesIO(b"\x00\x00")
+        mencoded = b"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"
+        mdecoded = base64.b64decode(mencoded)
+        malformed_header = io.BytesIO(mdecoded)
+
         with pytest.raises(SerializationError) as excinfo:
             test = aws_encryption_sdk.internal.formatting.deserialize.deserialize_header(malformed_header)
         excinfo.match(r"Malformed AAD: zero length AAD with non-zero length AAD length field")

test/unit/test_encryption_context.py

@@ -190,9 +190,11 @@ def test_deserialize_encryption_context_empty(self):
             serialized_encryption_context=b""
         )
         assert test == {}
-        
+
     def test_malformed_aad(self):
         malformed_aad = b"\x00\x00"
         with pytest.raises(SerializationError) as excinfo:
-            test = aws_encryption_sdk.internal.formatting.encryption_context.deserialize_encryption_context(malformed_aad)
+            test = aws_encryption_sdk.internal.formatting.encryption_context.deserialize_encryption_context(
+                malformed_aad
+            )
         excinfo.match(r"Malformed AAD: zero length AAD with non-zero length AAD length field")