Factor out an `is_mine_server_name` method (#15542)

Add an `is_mine_server_name` method, similar to `is_mine_id`.

Ideally we would use this consistently, instead of sometimes comparing
against `hs.hostname` and other times reaching into
`hs.config.server.server_name`.

Also fix a bug in the tests where `hs.hostname` would sometimes differ
from `hs.config.server.server_name`.

Signed-off-by: Sean Quah <seanq@matrix.org>

1 files changed, 2 insertions, 1 deletions

diff --git a/synapse/federation/federation_server.py b/synapse/federation/federation_server.py

index ca43c7bfc0..c590d8f96f 100644
--- a/synapse/federation/federation_server.py
+++ b/synapse/federation/federation_server.py
@@ -129,6 +129,7 @@ class FederationServer(FederationBase):
     def __init__(self, hs: "HomeServer"):
         super().__init__(hs)
 
+        self.server_name = hs.hostname
         self.handler = hs.get_federation_handler()
         self._spam_checker_module_callbacks = hs.get_module_api_callbacks().spam_checker
         self._federation_event_handler = hs.get_federation_event_handler()
@@ -942,7 +943,7 @@ class FederationServer(FederationBase):
             authorising_server = get_domain_from_id(
                 event.content[EventContentFields.AUTHORISING_USER]
             )
-            if authorising_server != self.server_name:
+            if not self._is_mine_server_name(authorising_server):
                 raise SynapseError(
                     400,
                     f"Cannot authorise request from resident server: {authorising_server}",