Fix incorrectly sending authentication tokens to application service as headers (#14301)

3 files changed, 13 insertions, 8 deletions

diff --git a/changelog.d/14301.bugfix b/changelog.d/14301.bugfix
new file mode 100644
index 0000000000..668c1f3b9c
--- /dev/null
+++ b/changelog.d/14301.bugfix
@@ -0,0 +1 @@
+Fix a bug introduced in Synapse 1.70.0rc1 where access tokens would be incorrectly sent to application services as headers. Application services which were obtaining access tokens from query parameters were not affected.
diff --git a/synapse/appservice/api.py b/synapse/appservice/api.py
index fbac4375b0..60774b240d 100644
--- a/synapse/appservice/api.py
+++ b/synapse/appservice/api.py
@@ -123,7 +123,7 @@ class ApplicationServiceApi(SimpleHttpClient):
             response = await self.get_json(
                 uri,
                 {"access_token": service.hs_token},
-                headers={"Authorization": f"Bearer {service.hs_token}"},
+                headers={"Authorization": [f"Bearer {service.hs_token}"]},
             )
             if response is not None:  # just an empty json object
                 return True
@@ -147,7 +147,7 @@ class ApplicationServiceApi(SimpleHttpClient):
             response = await self.get_json(
                 uri,
                 {"access_token": service.hs_token},
-                headers={"Authorization": f"Bearer {service.hs_token}"},
+                headers={"Authorization": [f"Bearer {service.hs_token}"]},
             )
             if response is not None:  # just an empty json object
                 return True
@@ -190,7 +190,9 @@ class ApplicationServiceApi(SimpleHttpClient):
                 b"access_token": service.hs_token,
             }
             response = await self.get_json(
-                uri, args=args, headers={"Authorization": f"Bearer {service.hs_token}"}
+                uri,
+                args=args,
+                headers={"Authorization": [f"Bearer {service.hs_token}"]},
             )
             if not isinstance(response, list):
                 logger.warning(
@@ -230,7 +232,7 @@ class ApplicationServiceApi(SimpleHttpClient):
                 info = await self.get_json(
                     uri,
                     {"access_token": service.hs_token},
-                    headers={"Authorization": f"Bearer {service.hs_token}"},
+                    headers={"Authorization": [f"Bearer {service.hs_token}"]},
                 )
 
                 if not _is_valid_3pe_metadata(info):
@@ -327,7 +329,7 @@ class ApplicationServiceApi(SimpleHttpClient):
                 uri=uri,
                 json_body=body,
                 args={"access_token": service.hs_token},
-                headers={"Authorization": f"Bearer {service.hs_token}"},
+                headers={"Authorization": [f"Bearer {service.hs_token}"]},
             )
             if logger.isEnabledFor(logging.DEBUG):
                 logger.debug(
diff --git a/tests/appservice/test_api.py b/tests/appservice/test_api.py
index 11008ac1fb..89ee79396f 100644
--- a/tests/appservice/test_api.py
+++ b/tests/appservice/test_api.py
@@ -11,7 +11,7 @@
 # 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.
-from typing import Any, List, Mapping
+from typing import Any, List, Mapping, Sequence, Union
 from unittest.mock import Mock
 
 from twisted.test.proto_helpers import MemoryReactor
@@ -70,13 +70,15 @@ class ApplicationServiceApiTestCase(unittest.HomeserverTestCase):
         self.request_url = None
 
         async def get_json(
-            url: str, args: Mapping[Any, Any], headers: Mapping[Any, Any]
+            url: str,
+            args: Mapping[Any, Any],
+            headers: Mapping[Union[str, bytes], Sequence[Union[str, bytes]]],
         ) -> List[JsonDict]:
             # Ensure the access token is passed as both a header and query arg.
             if not headers.get("Authorization") or not args.get(b"access_token"):
                 raise RuntimeError("Access token not provided")
 
-            self.assertEqual(headers.get("Authorization"), f"Bearer {TOKEN}")
+            self.assertEqual(headers.get("Authorization"), [f"Bearer {TOKEN}"])
             self.assertEqual(args.get(b"access_token"), TOKEN)
             self.request_url = url
             if url == URL_USER: