Merge branch 'validate-state-of-admins-room' into 'next'

Validate PDU in admins room

See merge request famedly/conduit!382

src/service/rooms/timeline/mod.rs

@@ -22,6 +22,7 @@
     },
     push::{Action, Ruleset, Tweak},
     state_res,
+    state_res::Event,
     state_res::RoomVersion,
     uint, CanonicalJsonObject, CanonicalJsonValue, EventId, OwnedEventId, OwnedRoomId,
     OwnedServerName, RoomAliasId, RoomId, UserId,
@@ -683,6 +684,92 @@ pub fn build_and_append_pdu(
         let (pdu, pdu_json) =
             self.create_hash_and_sign_event(pdu_builder, sender, room_id, state_lock)?;
 
+        let admin_room = services().rooms.alias.resolve_local_alias(
+            <&RoomAliasId>::try_from(
+                format!("#admins:{}", services().globals.server_name()).as_str(),
+            )
+            .expect("#admins:server_name is a valid room alias"),
+        )?;
+        if admin_room.filter(|v| v == room_id).is_some() {
+            match pdu.event_type() {
+                RoomEventType::RoomEncryption => {
+                    warn!("Encryption is not allowed in the admins room");
+                    return Err(Error::BadRequest(
+                        ErrorKind::Forbidden,
+                        "Encryption is not allowed in the admins room.",
+                    ));
+                }
+                RoomEventType::RoomMember => {
+                    #[derive(Deserialize)]
+                    struct ExtractMembership {
+                        membership: MembershipState,
+                    }
+
+                    let target = pdu
+                        .state_key()
+                        .filter(|v| v.starts_with("@"))
+                        .unwrap_or(sender.as_str());
+                    let server_name = services().globals.server_name();
+                    let server_user = format!("@conduit:{}", server_name);
+                    let content = serde_json::from_str::<ExtractMembership>(pdu.content.get())
+                        .map_err(|_| Error::bad_database("Invalid content in pdu."))?;
+
+                    if content.membership == MembershipState::Leave {
+                        if target == &server_user {
+                            warn!("Conduit user cannot leave from admins room");
+                            return Err(Error::BadRequest(
+                                ErrorKind::Forbidden,
+                                "Conduit user cannot leave from admins room.",
+                            ));
+                        }
+
+                        let count = services()
+                            .rooms
+                            .state_cache
+                            .room_members(room_id)
+                            .filter_map(|m| m.ok())
+                            .filter(|m| m.server_name() == server_name)
+                            .filter(|m| m != target)
+                            .count();
+                        if count < 2 {
+                            warn!("Last admin cannot leave from admins room");
+                            return Err(Error::BadRequest(
+                                ErrorKind::Forbidden,
+                                "Last admin cannot leave from admins room.",
+                            ));
+                        }
+                    }
+
+                    if content.membership == MembershipState::Ban && pdu.state_key().is_some() {
+                        if target == &server_user {
+                            warn!("Conduit user cannot be banned in admins room");
+                            return Err(Error::BadRequest(
+                                ErrorKind::Forbidden,
+                                "Conduit user cannot be banned in admins room.",
+                            ));
+                        }
+
+                        let count = services()
+                            .rooms
+                            .state_cache
+                            .room_members(room_id)
+                            .filter_map(|m| m.ok())
+                            .filter(|m| m.server_name() == server_name)
+                            .filter(|m| m != target)
+                            .count();
+                        if count < 2 {
+                            warn!("Last admin cannot be banned in admins room");
+                            return Err(Error::BadRequest(
+                                ErrorKind::Forbidden,
+                                "Last admin cannot be banned in admins room.",
+                            ));
+                        }
+                    }
+                }
+                _ => {}
+            }
+        }
+
         // We append to state before appending the pdu, so we don't have a moment in time with the
         // pdu without it's state. This is okay because append_pdu can't fail.
         let statehashid = services().rooms.state.append_to_state(&pdu)?;