From 2cb758ac75e529d9d093122a207ec43bcfa5f067 Mon Sep 17 00:00:00 2001
From: Erik Johnston <erik@matrix.org>
Date: Wed, 13 Jul 2016 13:12:25 +0100
Subject: [PATCH] Check if alias event's state_key matches sender's domain

---
 synapse/api/auth.py | 11 +++++++++++
 1 file changed, 11 insertions(+)

diff --git a/synapse/api/auth.py b/synapse/api/auth.py
index 29b4ac456..e05defd7d 100644
--- a/synapse/api/auth.py
+++ b/synapse/api/auth.py
@@ -115,6 +115,17 @@ class Auth(object):
 
             # FIXME: Temp hack
             if event.type == EventTypes.Aliases:
+                if not event.state_key:
+                    raise AuthError(
+                        403,
+                        "Alias event must have non-empty state_key"
+                    )
+                sender_domain = get_domain_from_id(event.sender)
+                if event.state_key != sender_domain:
+                    raise AuthError(
+                        403,
+                        "Alias event's state_key does not match sender's domain"
+                    )
                 return True
 
             logger.debug(