Merge pull request #256 from matrix-org/auth

Attempt to validate macaroons

7 files changed, 243 insertions, 19 deletions

diff --git a/synapse/api/auth.py b/synapse/api/auth.py
index 71a955b281..df788230fa 100644
--- a/synapse/api/auth.py
+++ b/synapse/api/auth.py
@@ -23,6 +23,7 @@ from synapse.util.logutils import log_function
 from synapse.types import UserID, EventID
 
 import logging
+import pymacaroons
 
 logger = logging.getLogger(__name__)
 
@@ -40,6 +41,12 @@ class Auth(object):
         self.store = hs.get_datastore()
         self.state = hs.get_state_handler()
         self.TOKEN_NOT_FOUND_HTTP_STATUS = 401
+        self._KNOWN_CAVEAT_PREFIXES = set([
+            "gen = ",
+            "type = ",
+            "time < ",
+            "user_id = ",
+        ])
 
     def check(self, event, auth_events):
         """ Checks if this event is correctly authed.
@@ -367,7 +374,7 @@ class Auth(object):
             except KeyError:
                 pass  # normal users won't have the user_id query parameter set.
 
-            user_info = yield self.get_user_by_access_token(access_token)
+            user_info = yield self._get_user_by_access_token(access_token)
             user = user_info["user"]
             token_id = user_info["token_id"]
 
@@ -394,7 +401,7 @@ class Auth(object):
             )
 
     @defer.inlineCallbacks
-    def get_user_by_access_token(self, token):
+    def _get_user_by_access_token(self, token):
         """ Get a registered user's ID.
 
         Args:
@@ -404,6 +411,86 @@ class Auth(object):
         Raises:
             AuthError if no user by that token exists or the token is invalid.
         """
+        try:
+            ret = yield self._get_user_from_macaroon(token)
+        except AuthError:
+            # TODO(daniel): Remove this fallback when all existing access tokens
+            # have been re-issued as macaroons.
+            ret = yield self._look_up_user_by_access_token(token)
+        defer.returnValue(ret)
+
+    @defer.inlineCallbacks
+    def _get_user_from_macaroon(self, macaroon_str):
+        try:
+            macaroon = pymacaroons.Macaroon.deserialize(macaroon_str)
+            self._validate_macaroon(macaroon)
+
+            user_prefix = "user_id = "
+            for caveat in macaroon.caveats:
+                if caveat.caveat_id.startswith(user_prefix):
+                    user = UserID.from_string(caveat.caveat_id[len(user_prefix):])
+                    # This codepath exists so that we can actually return a
+                    # token ID, because we use token IDs in place of device
+                    # identifiers throughout the codebase.
+                    # TODO(daniel): Remove this fallback when device IDs are
+                    # properly implemented.
+                    ret = yield self._look_up_user_by_access_token(macaroon_str)
+                    if ret["user"] != user:
+                        logger.error(
+                            "Macaroon user (%s) != DB user (%s)",
+                            user,
+                            ret["user"]
+                        )
+                        raise AuthError(
+                            self.TOKEN_NOT_FOUND_HTTP_STATUS,
+                            "User mismatch in macaroon",
+                            errcode=Codes.UNKNOWN_TOKEN
+                        )
+                    defer.returnValue(ret)
+            raise AuthError(
+                self.TOKEN_NOT_FOUND_HTTP_STATUS, "No user caveat in macaroon",
+                errcode=Codes.UNKNOWN_TOKEN
+            )
+        except (pymacaroons.exceptions.MacaroonException, TypeError, ValueError):
+            raise AuthError(
+                self.TOKEN_NOT_FOUND_HTTP_STATUS, "Invalid macaroon passed.",
+                errcode=Codes.UNKNOWN_TOKEN
+            )
+
+    def _validate_macaroon(self, macaroon):
+        v = pymacaroons.Verifier()
+        v.satisfy_exact("gen = 1")
+        v.satisfy_exact("type = access")
+        v.satisfy_general(lambda c: c.startswith("user_id = "))
+        v.satisfy_general(self._verify_expiry)
+        v.verify(macaroon, self.hs.config.macaroon_secret_key)
+
+        v = pymacaroons.Verifier()
+        v.satisfy_general(self._verify_recognizes_caveats)
+        v.verify(macaroon, self.hs.config.macaroon_secret_key)
+
+    def _verify_expiry(self, caveat):
+        prefix = "time < "
+        if not caveat.startswith(prefix):
+            return False
+        # TODO(daniel): Enable expiry check when clients actually know how to
+        # refresh tokens. (And remember to enable the tests)
+        return True
+        expiry = int(caveat[len(prefix):])
+        now = self.hs.get_clock().time_msec()
+        return now < expiry
+
+    def _verify_recognizes_caveats(self, caveat):
+        first_space = caveat.find(" ")
+        if first_space < 0:
+            return False
+        second_space = caveat.find(" ", first_space + 1)
+        if second_space < 0:
+            return False
+        return caveat[:second_space + 1] in self._KNOWN_CAVEAT_PREFIXES
+
+    @defer.inlineCallbacks
+    def _look_up_user_by_access_token(self, token):
         ret = yield self.store.get_user_by_access_token(token)
         if not ret:
             raise AuthError(
@@ -414,7 +501,6 @@ class Auth(object):
             "user": UserID.from_string(ret.get("name")),
             "token_id": ret.get("token_id", None),
         }
-
         defer.returnValue(user_info)
 
     @defer.inlineCallbacks
diff --git a/tests/api/test_auth.py b/tests/api/test_auth.py
index 22fc804331..c96273480d 100644
--- a/tests/api/test_auth.py
+++ b/tests/api/test_auth.py
@@ -19,17 +19,21 @@ from mock import Mock
 
 from synapse.api.auth import Auth
 from synapse.api.errors import AuthError
+from synapse.types import UserID
+from tests.utils import setup_test_homeserver
+
+import pymacaroons
 
 
 class AuthTestCase(unittest.TestCase):
 
+    @defer.inlineCallbacks
     def setUp(self):
         self.state_handler = Mock()
         self.store = Mock()
 
-        self.hs = Mock()
+        self.hs = yield setup_test_homeserver(handlers=None)
         self.hs.get_datastore = Mock(return_value=self.store)
-        self.hs.get_state_handler = Mock(return_value=self.state_handler)
         self.auth = Auth(self.hs)
 
         self.test_user = "@foo:bar"
@@ -133,3 +137,140 @@ class AuthTestCase(unittest.TestCase):
         request.requestHeaders.getRawHeaders = Mock(return_value=[""])
         d = self.auth.get_user_by_req(request)
         self.failureResultOf(d, AuthError)
+
+    @defer.inlineCallbacks
+    def test_get_user_from_macaroon(self):
+        # TODO(danielwh): Remove this mock when we remove the
+        # get_user_by_access_token fallback.
+        self.store.get_user_by_access_token = Mock(
+            return_value={"name": "@baldrick:matrix.org"}
+        )
+
+        user_id = "@baldrick:matrix.org"
+        macaroon = pymacaroons.Macaroon(
+            location=self.hs.config.server_name,
+            identifier="key",
+            key=self.hs.config.macaroon_secret_key)
+        macaroon.add_first_party_caveat("gen = 1")
+        macaroon.add_first_party_caveat("type = access")
+        macaroon.add_first_party_caveat("user_id = %s" % (user_id,))
+        user_info = yield self.auth._get_user_from_macaroon(macaroon.serialize())
+        user = user_info["user"]
+        self.assertEqual(UserID.from_string(user_id), user)
+
+    @defer.inlineCallbacks
+    def test_get_user_from_macaroon_user_db_mismatch(self):
+        self.store.get_user_by_access_token = Mock(
+            return_value={"name": "@percy:matrix.org"}
+        )
+
+        user = "@baldrick:matrix.org"
+        macaroon = pymacaroons.Macaroon(
+            location=self.hs.config.server_name,
+            identifier="key",
+            key=self.hs.config.macaroon_secret_key)
+        macaroon.add_first_party_caveat("gen = 1")
+        macaroon.add_first_party_caveat("type = access")
+        macaroon.add_first_party_caveat("user_id = %s" % (user,))
+        with self.assertRaises(AuthError) as cm:
+            yield self.auth._get_user_from_macaroon(macaroon.serialize())
+        self.assertEqual(401, cm.exception.code)
+        self.assertIn("User mismatch", cm.exception.msg)
+
+    @defer.inlineCallbacks
+    def test_get_user_from_macaroon_missing_caveat(self):
+        # TODO(danielwh): Remove this mock when we remove the
+        # get_user_by_access_token fallback.
+        self.store.get_user_by_access_token = Mock(
+            return_value={"name": "@baldrick:matrix.org"}
+        )
+
+        macaroon = pymacaroons.Macaroon(
+            location=self.hs.config.server_name,
+            identifier="key",
+            key=self.hs.config.macaroon_secret_key)
+        macaroon.add_first_party_caveat("gen = 1")
+        macaroon.add_first_party_caveat("type = access")
+
+        with self.assertRaises(AuthError) as cm:
+            yield self.auth._get_user_from_macaroon(macaroon.serialize())
+        self.assertEqual(401, cm.exception.code)
+        self.assertIn("No user caveat", cm.exception.msg)
+
+    @defer.inlineCallbacks
+    def test_get_user_from_macaroon_wrong_key(self):
+        # TODO(danielwh): Remove this mock when we remove the
+        # get_user_by_access_token fallback.
+        self.store.get_user_by_access_token = Mock(
+            return_value={"name": "@baldrick:matrix.org"}
+        )
+
+        user = "@baldrick:matrix.org"
+        macaroon = pymacaroons.Macaroon(
+            location=self.hs.config.server_name,
+            identifier="key",
+            key=self.hs.config.macaroon_secret_key + "wrong")
+        macaroon.add_first_party_caveat("gen = 1")
+        macaroon.add_first_party_caveat("type = access")
+        macaroon.add_first_party_caveat("user_id = %s" % (user,))
+
+        with self.assertRaises(AuthError) as cm:
+            yield self.auth._get_user_from_macaroon(macaroon.serialize())
+        self.assertEqual(401, cm.exception.code)
+        self.assertIn("Invalid macaroon", cm.exception.msg)
+
+    @defer.inlineCallbacks
+    def test_get_user_from_macaroon_unknown_caveat(self):
+        # TODO(danielwh): Remove this mock when we remove the
+        # get_user_by_access_token fallback.
+        self.store.get_user_by_access_token = Mock(
+            return_value={"name": "@baldrick:matrix.org"}
+        )
+
+        user = "@baldrick:matrix.org"
+        macaroon = pymacaroons.Macaroon(
+            location=self.hs.config.server_name,
+            identifier="key",
+            key=self.hs.config.macaroon_secret_key)
+        macaroon.add_first_party_caveat("gen = 1")
+        macaroon.add_first_party_caveat("type = access")
+        macaroon.add_first_party_caveat("user_id = %s" % (user,))
+        macaroon.add_first_party_caveat("cunning > fox")
+
+        with self.assertRaises(AuthError) as cm:
+            yield self.auth._get_user_from_macaroon(macaroon.serialize())
+        self.assertEqual(401, cm.exception.code)
+        self.assertIn("Invalid macaroon", cm.exception.msg)
+
+    @defer.inlineCallbacks
+    def test_get_user_from_macaroon_expired(self):
+        # TODO(danielwh): Remove this mock when we remove the
+        # get_user_by_access_token fallback.
+        self.store.get_user_by_access_token = Mock(
+            return_value={"name": "@baldrick:matrix.org"}
+        )
+
+        self.store.get_user_by_access_token = Mock(
+            return_value={"name": "@baldrick:matrix.org"}
+        )
+
+        user = "@baldrick:matrix.org"
+        macaroon = pymacaroons.Macaroon(
+            location=self.hs.config.server_name,
+            identifier="key",
+            key=self.hs.config.macaroon_secret_key)
+        macaroon.add_first_party_caveat("gen = 1")
+        macaroon.add_first_party_caveat("type = access")
+        macaroon.add_first_party_caveat("user_id = %s" % (user,))
+        macaroon.add_first_party_caveat("time < 1") # ms
+
+        self.hs.clock.now = 5000 # seconds
+
+        yield self.auth._get_user_from_macaroon(macaroon.serialize())
+        # TODO(daniel): Turn on the check that we validate expiration, when we
+        # validate expiration (and remove the above line, which will start
+        # throwing).
+        # with self.assertRaises(AuthError) as cm:
+        #     yield self.auth._get_user_from_macaroon(macaroon.serialize())
+        # self.assertEqual(401, cm.exception.code)
+        # self.assertIn("Invalid macaroon", cm.exception.msg)
diff --git a/tests/rest/client/v1/test_presence.py b/tests/rest/client/v1/test_presence.py
index 91547bdd06..2ee3da0b34 100644
--- a/tests/rest/client/v1/test_presence.py
+++ b/tests/rest/client/v1/test_presence.py
@@ -76,7 +76,7 @@ class PresenceStateTestCase(unittest.TestCase):
                 "token_id": 1,
             }
 
-        hs.get_v1auth().get_user_by_access_token = _get_user_by_access_token
+        hs.get_v1auth()._get_user_by_access_token = _get_user_by_access_token
 
         room_member_handler = hs.handlers.room_member_handler = Mock(
             spec=[
@@ -169,7 +169,7 @@ class PresenceListTestCase(unittest.TestCase):
             ]
         )
 
-        hs.get_v1auth().get_user_by_access_token = _get_user_by_access_token
+        hs.get_v1auth()._get_user_by_access_token = _get_user_by_access_token
 
         presence.register_servlets(hs, self.mock_resource)
 
diff --git a/tests/rest/client/v1/test_rooms.py b/tests/rest/client/v1/test_rooms.py
index 34ab47d02e..9fb2bfb315 100644
--- a/tests/rest/client/v1/test_rooms.py
+++ b/tests/rest/client/v1/test_rooms.py
@@ -59,7 +59,7 @@ class RoomPermissionsTestCase(RestTestCase):
                 "user": UserID.from_string(self.auth_user_id),
                 "token_id": 1,
             }
-        hs.get_v1auth().get_user_by_access_token = _get_user_by_access_token
+        hs.get_v1auth()._get_user_by_access_token = _get_user_by_access_token
 
         def _insert_client_ip(*args, **kwargs):
             return defer.succeed(None)
@@ -444,7 +444,7 @@ class RoomsMemberListTestCase(RestTestCase):
                 "user": UserID.from_string(self.auth_user_id),
                 "token_id": 1,
             }
-        hs.get_v1auth().get_user_by_access_token = _get_user_by_access_token
+        hs.get_v1auth()._get_user_by_access_token = _get_user_by_access_token
 
         def _insert_client_ip(*args, **kwargs):
             return defer.succeed(None)
@@ -522,7 +522,7 @@ class RoomsCreateTestCase(RestTestCase):
                 "user": UserID.from_string(self.auth_user_id),
                 "token_id": 1,
             }
-        hs.get_v1auth().get_user_by_access_token = _get_user_by_access_token
+        hs.get_v1auth()._get_user_by_access_token = _get_user_by_access_token
 
         def _insert_client_ip(*args, **kwargs):
             return defer.succeed(None)
@@ -614,7 +614,7 @@ class RoomTopicTestCase(RestTestCase):
                 "token_id": 1,
             }
 
-        hs.get_v1auth().get_user_by_access_token = _get_user_by_access_token
+        hs.get_v1auth()._get_user_by_access_token = _get_user_by_access_token
 
         def _insert_client_ip(*args, **kwargs):
             return defer.succeed(None)
@@ -718,7 +718,7 @@ class RoomMemberStateTestCase(RestTestCase):
                 "user": UserID.from_string(self.auth_user_id),
                 "token_id": 1,
             }
-        hs.get_v1auth().get_user_by_access_token = _get_user_by_access_token
+        hs.get_v1auth()._get_user_by_access_token = _get_user_by_access_token
 
         def _insert_client_ip(*args, **kwargs):
             return defer.succeed(None)
@@ -843,7 +843,7 @@ class RoomMessagesTestCase(RestTestCase):
                 "user": UserID.from_string(self.auth_user_id),
                 "token_id": 1,
             }
-        hs.get_v1auth().get_user_by_access_token = _get_user_by_access_token
+        hs.get_v1auth()._get_user_by_access_token = _get_user_by_access_token
 
         def _insert_client_ip(*args, **kwargs):
             return defer.succeed(None)
@@ -938,7 +938,7 @@ class RoomInitialSyncTestCase(RestTestCase):
                 "user": UserID.from_string(self.auth_user_id),
                 "token_id": 1,
             }
-        hs.get_v1auth().get_user_by_access_token = _get_user_by_access_token
+        hs.get_v1auth()._get_user_by_access_token = _get_user_by_access_token
 
         def _insert_client_ip(*args, **kwargs):
             return defer.succeed(None)
diff --git a/tests/rest/client/v1/test_typing.py b/tests/rest/client/v1/test_typing.py
index 1c4519406d..6395ce79db 100644
--- a/tests/rest/client/v1/test_typing.py
+++ b/tests/rest/client/v1/test_typing.py
@@ -67,7 +67,7 @@ class RoomTypingTestCase(RestTestCase):
                 "token_id": 1,
             }
 
-        hs.get_v1auth().get_user_by_access_token = _get_user_by_access_token
+        hs.get_v1auth()._get_user_by_access_token = _get_user_by_access_token
 
         def _insert_client_ip(*args, **kwargs):
             return defer.succeed(None)
diff --git a/tests/rest/client/v1/utils.py b/tests/rest/client/v1/utils.py
index c472d53043..85096a0326 100644
--- a/tests/rest/client/v1/utils.py
+++ b/tests/rest/client/v1/utils.py
@@ -37,9 +37,6 @@ class RestTestCase(unittest.TestCase):
         self.mock_resource = None
         self.auth_user_id = None
 
-    def mock_get_user_by_access_token(self, token=None):
-        return self.auth_user_id
-
     @defer.inlineCallbacks
     def create_room_as(self, room_creator, is_public=True, tok=None):
         temp_id = self.auth_user_id
diff --git a/tests/rest/client/v2_alpha/__init__.py b/tests/rest/client/v2_alpha/__init__.py
index ef972a53aa..f45570a1c0 100644
--- a/tests/rest/client/v2_alpha/__init__.py
+++ b/tests/rest/client/v2_alpha/__init__.py
@@ -48,7 +48,7 @@ class V2AlphaRestTestCase(unittest.TestCase):
                 "user": UserID.from_string(self.USER_ID),
                 "token_id": 1,
             }
-        hs.get_auth().get_user_by_access_token = _get_user_by_access_token
+        hs.get_auth()._get_user_by_access_token = _get_user_by_access_token
 
         for r in self.TO_REGISTER:
             r.register_servlets(hs, self.mock_resource)