From bfb95654c97a8d3aa164eff96ecc13755c1c326d Mon Sep 17 00:00:00 2001
From: Will Hunt <will@half-shot.uk>
Date: Mon, 16 Dec 2019 16:11:55 +0000
Subject: [PATCH] Add option to allow profile queries without sharing a room
 (#6523)

---
 changelog.d/6523.feature             |  1 +
 docs/sample_config.yaml              |  7 +++++++
 synapse/config/server.py             | 13 +++++++++++++
 synapse/handlers/profile.py          |  6 +++++-
 tests/rest/client/v1/test_profile.py |  2 ++
 5 files changed, 28 insertions(+), 1 deletion(-)
 create mode 100644 changelog.d/6523.feature

diff --git a/changelog.d/6523.feature b/changelog.d/6523.feature
new file mode 100644
index 000000000..798fa143d
--- /dev/null
+++ b/changelog.d/6523.feature
@@ -0,0 +1 @@
+Add option `limit_profile_requests_to_users_who_share_rooms` to prevent requirement of a local user sharing a room with another user to query their profile information.
diff --git a/docs/sample_config.yaml b/docs/sample_config.yaml
index 4d44e631d..1787248f5 100644
--- a/docs/sample_config.yaml
+++ b/docs/sample_config.yaml
@@ -54,6 +54,13 @@ pid_file: DATADIR/homeserver.pid
 #
 #require_auth_for_profile_requests: true
 
+# Uncomment to require a user to share a room with another user in order
+# to retrieve their profile information. Only checked on Client-Server
+# requests. Profile requests from other servers should be checked by the
+# requesting server. Defaults to 'false'.
+#
+#limit_profile_requests_to_users_who_share_rooms: true
+
 # If set to 'true', removes the need for authentication to access the server's
 # public rooms directory through the client API, meaning that anyone can
 # query the room directory. Defaults to 'false'.
diff --git a/synapse/config/server.py b/synapse/config/server.py
index 50af858c7..38f6ff9ed 100644
--- a/synapse/config/server.py
+++ b/synapse/config/server.py
@@ -102,6 +102,12 @@ class ServerConfig(Config):
             "require_auth_for_profile_requests", False
         )
 
+        # Whether to require sharing a room with a user to retrieve their
+        # profile data
+        self.limit_profile_requests_to_users_who_share_rooms = config.get(
+            "limit_profile_requests_to_users_who_share_rooms", False,
+        )
+
         if "restrict_public_rooms_to_local_users" in config and (
             "allow_public_rooms_without_auth" in config
             or "allow_public_rooms_over_federation" in config
@@ -621,6 +627,13 @@ class ServerConfig(Config):
         #
         #require_auth_for_profile_requests: true
 
+        # Uncomment to require a user to share a room with another user in order
+        # to retrieve their profile information. Only checked on Client-Server
+        # requests. Profile requests from other servers should be checked by the
+        # requesting server. Defaults to 'false'.
+        #
+        #limit_profile_requests_to_users_who_share_rooms: true
+
         # If set to 'true', removes the need for authentication to access the server's
         # public rooms directory through the client API, meaning that anyone can
         # query the room directory. Defaults to 'false'.
diff --git a/synapse/handlers/profile.py b/synapse/handlers/profile.py
index 1e5a4613c..f9579d69e 100644
--- a/synapse/handlers/profile.py
+++ b/synapse/handlers/profile.py
@@ -295,12 +295,16 @@ class BaseProfileHandler(BaseHandler):
                 be found to be in any room the server is in, and therefore the query
                 is denied.
         """
+
         # Implementation of MSC1301: don't allow looking up profiles if the
         # requester isn't in the same room as the target. We expect requester to
         # be None when this function is called outside of a profile query, e.g.
         # when building a membership event. In this case, we must allow the
         # lookup.
-        if not self.hs.config.require_auth_for_profile_requests or not requester:
+        if (
+            not self.hs.config.limit_profile_requests_to_users_who_share_rooms
+            or not requester
+        ):
             return
 
         # Always allow the user to query their own profile.
diff --git a/tests/rest/client/v1/test_profile.py b/tests/rest/client/v1/test_profile.py
index 12c5e95cb..8df58b4a6 100644
--- a/tests/rest/client/v1/test_profile.py
+++ b/tests/rest/client/v1/test_profile.py
@@ -237,6 +237,7 @@ class ProfilesRestrictedTestCase(unittest.HomeserverTestCase):
 
         config = self.default_config()
         config["require_auth_for_profile_requests"] = True
+        config["limit_profile_requests_to_users_who_share_rooms"] = True
         self.hs = self.setup_test_homeserver(config=config)
 
         return self.hs
@@ -309,6 +310,7 @@ class OwnProfileUnrestrictedTestCase(unittest.HomeserverTestCase):
     def make_homeserver(self, reactor, clock):
         config = self.default_config()
         config["require_auth_for_profile_requests"] = True
+        config["limit_profile_requests_to_users_who_share_rooms"] = True
         self.hs = self.setup_test_homeserver(config=config)
 
         return self.hs