From 054a6d4268533ab3866ab9be48c6f499c29a6d02 Mon Sep 17 00:00:00 2001
From: Alex Auvolat <alex@adnab.me>
Date: Sun, 5 Apr 2020 12:52:55 +0200
Subject: [PATCH] Tolerate more invalid inputs from synapse

---
 server.go | 30 ++++++++++++++++++++++++------
 1 file changed, 24 insertions(+), 6 deletions(-)

diff --git a/server.go b/server.go
index e87dad2..84a693e 100644
--- a/server.go
+++ b/server.go
@@ -117,7 +117,7 @@ func handleTxn(w http.ResponseWriter, r *http.Request) {
 			}
 			err = handleTxnEvent(ev)
 			if err != nil {
-				ezbrSystemSend(ev.Sender, fmt.Sprintf("Could not process %s (%s): %s", ev.Type, ev.Sender, err))
+				ezbrSystemSend(ev.Sender, fmt.Sprintf("Could not process %s (from %s): %s", ev.Type, ev.Sender, err))
 			}
 		}
 
@@ -129,12 +129,21 @@ func handleTxn(w http.ResponseWriter, r *http.Request) {
 
 func handleTxnEvent(e *mxlib.Event) error {
 	if e.Type == "m.room.message" {
+		e_body, ok := e.Content["body"].(string)
+		if !ok {
+			return fmt.Errorf("Invalid m.room.message event, body is not defined: %#v", e)
+		}
+		typ, ok := e.Content["msgtype"].(string)
+		if !ok {
+			return fmt.Errorf("Invalid m.room.message event, msgtype is not defined: %#v", e)
+		}
+
 		ev := &connector.Event{
 			Type: connector.EVENT_MESSAGE,
-			Text: e.Content["body"].(string),
+			Text: e_body,
 			Id:   e.EventId,
 		}
-		typ := e.Content["msgtype"].(string)
+
 		if typ == "m.emote" {
 			ev.Type = connector.EVENT_MESSAGE
 		} else if typ == "m.file" || typ == "m.image" {
@@ -146,7 +155,7 @@ func handleTxnEvent(e *mxlib.Event) error {
 
 		if pm_room := dbIsPmRoom(e.RoomId); pm_room != nil {
 			if pm_room.Protocol == EASYBRIDGE_SYSTEM_PROTOCOL {
-				handleSystemMessage(e.Sender, e.Content["body"].(string))
+				handleSystemMessage(e.Sender, e_body)
 				return nil
 			}
 			// If this is a private message room
@@ -185,7 +194,11 @@ func handleTxnEvent(e *mxlib.Event) error {
 			return fmt.Errorf("Room not bridged")
 		}
 	} else if e.Type == "m.room.member" {
-		ms := e.Content["membership"].(string)
+		ms, ok := e.Content["membership"].(string)
+		if !ok {
+			return fmt.Errorf("Invalid m.room.member event, membership is not defined: %#v", e)
+		}
+
 		if ms == "leave" {
 			if pm_room := dbIsPmRoom(e.RoomId); pm_room != nil {
 				// If user leaves a PM room, we must drop it
@@ -209,11 +222,16 @@ func handleTxnEvent(e *mxlib.Event) error {
 			}
 		}
 	} else if e.Type == "m.room.topic" {
+		e_topic, ok := e.Content["topic"].(string)
+		if !ok {
+			return fmt.Errorf("Invalid m.room.topic event, topic is not defined: %#v", e)
+		}
+
 		if room := dbIsPublicRoom(e.RoomId); room != nil {
 			acct := FindJoinedAccount(e.Sender, room.Protocol, room.RoomID)
 			if acct != nil {
 				return acct.Conn.SetRoomInfo(room.RoomID, &connector.RoomInfo{
-					Topic: e.Content["topic"].(string),
+					Topic: e_topic,
 				})
 			} else {
 				return fmt.Errorf("Could not find room account for %s %s %s", e.Sender, room.Protocol, room.RoomID)