diff --git a/CHANGELOG.md b/CHANGELOG.md index 63c2f0f..3ba3370 100644 --- a/CHANGELOG.md +++ b/CHANGELOG.md @@ -2,6 +2,10 @@ ## [unreleased] +### Added +* New style Diaspora private encrypted JSON payloads are now supported in the receiving side. Outbound private Diaspora payloads are still sent as legacy encrypted payloads. ([issue](https://github.com/jaywink/federation/issues/83)) + * No additional changes need to be made when calling `handle_receive` from your task processing. Just pass in the full received XML or JSON payload as a string with recipient user object as before. + ### Fixed * Fix getting sender from a combination of legacy Diaspora encrypted payload and new entity names (for example `author`). This combination probably only existed in this library. * Correctly extend entity `_children`. Certain Diaspora payloads caused `_children` for an entity to be written over by an empty list, causing for example status message photos to not be saved. Correctly do an extend on it. ([issue](https://github.com/jaywink/federation/issues/89)) @@ -9,6 +13,7 @@ ### Removed * `Post.photos` entity attribute was never used by any code and has been removed. Child entities of type `Image` are stored in the `Post._children` as before. +* Removed deprecated user private key lookup using `user.key` in Diaspora receive processing. Passed in `user` objects must now have a `private_key` attribute. ## [0.12.0] - 2017-05-22 diff --git a/federation/protocols/base.py b/federation/protocols/base.py index 0f48de3..e298ce0 100644 --- a/federation/protocols/base.py +++ b/federation/protocols/base.py @@ -37,7 +37,7 @@ class BaseProtocol(object): """ raise NotImplementedError("Implement in subclass") - def receive(self, payload, user=None, sender_key_fetcher=None, *args, **kwargs): + def receive(self, payload, user=None, sender_key_fetcher=None): """Receive a payload. Args: diff --git a/federation/protocols/diaspora/encrypted.py b/federation/protocols/diaspora/encrypted.py new file mode 100644 index 0000000..ccf23a4 --- /dev/null +++ b/federation/protocols/diaspora/encrypted.py @@ -0,0 +1,30 @@ +import json +from base64 import b64decode + +from Crypto.Cipher import PKCS1_v1_5, AES +from lxml import etree + + +def pkcs7_unpad(data): + """Remove the padding bytes that were added at point of encryption.""" + if isinstance(data, str): + return data[0:-ord(data[-1])] + else: + return data[0:-data[-1]] + + +class EncryptedPayload: + """Diaspora encrypted JSON payloads.""" + + @staticmethod + def decrypt(payload, private_key): + """Decrypt an encrypted JSON payload and return the Magic Envelope document inside.""" + cipher = PKCS1_v1_5.new(private_key) + aes_key_str = cipher.decrypt(b64decode(payload.get("aes_key")), sentinel=None) + aes_key = json.loads(aes_key_str.decode("utf-8")) + key = b64decode(aes_key.get("key")) + iv = b64decode(aes_key.get("iv")) + encrypted_magic_envelope = b64decode(payload.get("encrypted_magic_envelope")) + encrypter = AES.new(key, AES.MODE_CBC, iv) + content = encrypter.decrypt(encrypted_magic_envelope) + return etree.fromstring(pkcs7_unpad(content)) diff --git a/federation/protocols/diaspora/magic_envelope.py b/federation/protocols/diaspora/magic_envelope.py index ff9cc13..46a9a08 100644 --- a/federation/protocols/diaspora/magic_envelope.py +++ b/federation/protocols/diaspora/magic_envelope.py @@ -8,7 +8,7 @@ from lxml import etree NAMESPACE = "http://salmon-protocol.org/ns/magic-env" -class MagicEnvelope(): +class MagicEnvelope: """Diaspora protocol magic envelope. See: http://diaspora.github.io/diaspora_federation/federation/magicsig.html diff --git a/federation/protocols/diaspora/protocol.py b/federation/protocols/diaspora/protocol.py index e65d3ef..73c417e 100644 --- a/federation/protocols/diaspora/protocol.py +++ b/federation/protocols/diaspora/protocol.py @@ -1,6 +1,5 @@ import json import logging -import warnings from base64 import b64decode, urlsafe_b64decode, b64encode, urlsafe_b64encode from urllib.parse import unquote_plus @@ -13,7 +12,9 @@ from lxml import etree from federation.exceptions import EncryptedMessageError, NoSenderKeyFoundError, SignatureVerificationError from federation.protocols.base import BaseProtocol +from federation.protocols.diaspora.encrypted import EncryptedPayload from federation.protocols.diaspora.magic_envelope import MagicEnvelope +from federation.utils.text import decode_if_bytes logger = logging.getLogger("federation") @@ -29,7 +30,7 @@ def identify_payload(payload): """ # Private encrypted JSON payload try: - data = json.loads(payload) + data = json.loads(decode_if_bytes(payload)) if "encrypted_magic_envelope" in data: return True except Exception: @@ -55,17 +56,36 @@ class Protocol(BaseProtocol): Mostly taken from Pyaspora (https://github.com/lukeross/pyaspora). """ - def receive(self, payload, user=None, sender_key_fetcher=None, skip_author_verification=False, *args, **kwargs): + def __init__(self): + super().__init__() + self.encrypted = self.legacy = False + + def get_json_payload_magic_envelope(self, payload): + """Encrypted JSON payload""" + private_key = self._get_user_key(self.user) + return EncryptedPayload.decrypt(payload=payload, private_key=private_key) + + def store_magic_envelope_doc(self, payload): + """Get the Magic Envelope, trying JSON first.""" + try: + json_payload = json.loads(decode_if_bytes(payload)) + except ValueError: + # XML payload + xml = unquote_plus(payload) + xml = xml.lstrip().encode("utf-8") + logger.debug("diaspora.protocol.store_magic_envelope_doc: xml payload: %s", xml) + self.doc = etree.fromstring(xml) + else: + logger.debug("diaspora.protocol.store_magic_envelope_doc: json payload: %s", json_payload) + self.doc = self.get_json_payload_magic_envelope(json_payload) + + def receive(self, payload, user=None, sender_key_fetcher=None, skip_author_verification=False): """Receive a payload. For testing purposes, `skip_author_verification` can be passed. Authorship will not be verified.""" self.user = user self.get_contact_key = sender_key_fetcher - # Prepare payload - xml = unquote_plus(payload) - xml = xml.lstrip().encode("utf-8") - logger.debug("diaspora.protocol.receive: xml content: %s", xml) - self.doc = etree.fromstring(xml) + self.store_magic_envelope_doc(payload) # Check for a legacy header self.find_header() # Open payload and get actual message @@ -78,17 +98,11 @@ class Protocol(BaseProtocol): return self.sender_handle, self.content def _get_user_key(self, user): - if not hasattr(self.user, "private_key") or not self.user.private_key: - if hasattr(self.user, "key") and self.user.key: - warnings.warn("Using `key` in user object for private key has been deprecated. Please " - "have available `private_key` instead. Usage of `key` will be removed after 0.8.0.", - DeprecationWarning) - return self.user.key + if not getattr(self.user, "private_key", None): raise EncryptedMessageError("Cannot decrypt private message without user key") return self.user.private_key def find_header(self): - self.encrypted = self.legacy = False self.header = self.doc.find(".//{"+PROTOCOL_NS+"}header") if self.header != None: # Legacy public header found diff --git a/federation/tests/protocols/diaspora/test_encrypted.py b/federation/tests/protocols/diaspora/test_encrypted.py new file mode 100644 index 0000000..5d10988 --- /dev/null +++ b/federation/tests/protocols/diaspora/test_encrypted.py @@ -0,0 +1,33 @@ +from unittest.mock import patch, Mock + +from Crypto.Cipher import AES + +from federation.protocols.diaspora.encrypted import pkcs7_unpad, EncryptedPayload + + +def test_pkcs7_unpad(): + assert pkcs7_unpad(b"foobar\x02\x02") == b"foobar" + assert pkcs7_unpad("foobar\x02\x02") == "foobar" + + +class TestEncryptedPayload: + @patch("federation.protocols.diaspora.encrypted.PKCS1_v1_5.new") + @patch("federation.protocols.diaspora.encrypted.AES.new") + @patch("federation.protocols.diaspora.encrypted.pkcs7_unpad", side_effect=lambda x: x) + @patch("federation.protocols.diaspora.encrypted.b64decode", side_effect=lambda x: x) + def test_decrypt(self, mock_decode, mock_unpad, mock_aes, mock_pkcs1): + mock_decrypt = Mock(return_value=b'{"iv": "foo", "key": "bar"}') + mock_pkcs1.return_value = Mock(decrypt=mock_decrypt) + mock_encrypter = Mock(return_value="bar") + mock_aes.return_value = Mock(decrypt=mock_encrypter) + doc = EncryptedPayload.decrypt( + {"aes_key": '{"iv": "foo", "key": "bar"}', "encrypted_magic_envelope": "magically encrypted"}, + "private_key", + ) + mock_pkcs1.assert_called_once_with("private_key") + mock_decrypt.assert_called_once_with('{"iv": "foo", "key": "bar"}', sentinel=None) + assert mock_decode.call_count == 4 + mock_aes.assert_called_once_with("bar", AES.MODE_CBC, "foo") + mock_encrypter.assert_called_once_with("magically encrypted") + assert doc.tag == "foo" + assert doc.text == "bar" diff --git a/federation/tests/protocols/diaspora/test_protocol.py b/federation/tests/protocols/diaspora/test_protocol.py index 3fd5a37..f33a31a 100644 --- a/federation/tests/protocols/diaspora/test_protocol.py +++ b/federation/tests/protocols/diaspora/test_protocol.py @@ -155,3 +155,24 @@ class TestDiasporaProtocol(DiasporaTestBase): data = protocol.build_send(entity, from_user) mock_init_message.assert_called_once_with(mock_entity_xml, from_user.handle, from_user.private_key) assert data == {"xml": "xmldata"} + + @patch("federation.protocols.diaspora.protocol.EncryptedPayload.decrypt") + def test_get_json_payload_magic_envelope(self, mock_decrypt): + protocol = Protocol() + protocol.user = MockUser() + protocol.get_json_payload_magic_envelope("payload") + mock_decrypt.assert_called_once_with(payload="payload", private_key="foobar") + + @patch.object(Protocol, "get_json_payload_magic_envelope", return_value=etree.fromstring("bar")) + def test_store_magic_envelope_doc_json_payload(self, mock_store): + protocol = Protocol() + protocol.store_magic_envelope_doc('{"foo": "bar"}') + mock_store.assert_called_once_with({"foo": "bar"}) + assert protocol.doc.tag == "foo" + assert protocol.doc.text == "bar" + + def test_store_magic_envelope_doc_xml_payload(self): + protocol = Protocol() + protocol.store_magic_envelope_doc("bar") + assert protocol.doc.tag == "foo" + assert protocol.doc.text == "bar" diff --git a/federation/tests/utils/test_text.py b/federation/tests/utils/test_text.py new file mode 100644 index 0000000..7f629d3 --- /dev/null +++ b/federation/tests/utils/test_text.py @@ -0,0 +1,6 @@ +from federation.utils.text import decode_if_bytes + + +def test_decode_if_bytes(): + assert decode_if_bytes(b"foobar") == "foobar" + assert decode_if_bytes("foobar") == "foobar" diff --git a/federation/utils/text.py b/federation/utils/text.py new file mode 100644 index 0000000..310a5e1 --- /dev/null +++ b/federation/utils/text.py @@ -0,0 +1,5 @@ +def decode_if_bytes(text): + try: + return text.decode("utf-8") + except AttributeError: + return text