Hacked clients can't send chat messages from other characters anymore

Also added sendername as userdata in chat messages, for now it's not used for anything but we'll probably find something where this is useful

Subsurface/Source/Networking/ChatMessage.cs

@@ -117,8 +117,11 @@ namespace Barotrauma.Networking
         public void WriteNetworkMessage(NetOutgoingMessage msg)
         {
             msg.WriteRangedInteger(0, Enum.GetValues(typeof(ChatMessageType)).Length, (byte)Type);
-            msg.Write(Sender == null ? (ushort)0 : Sender.ID);
+            if (GameMain.Server != null)
-            msg.Write(SenderName);
+            {
+                msg.Write(Sender == null ? (ushort)0 : Sender.ID);
+                msg.Write(SenderName);
+            }
 
             msg.Write(Text);  
         }
@@ -126,11 +129,33 @@ namespace Barotrauma.Networking
         public static ChatMessage ReadNetworkMessage(NetBuffer msg)
         {
             ChatMessageType type = (ChatMessageType)msg.ReadRangedInteger(0, Enum.GetValues(typeof(ChatMessageType)).Length);
-            ushort senderId = msg.ReadUInt16();
+            string senderName="";
-            string senderName = msg.ReadString();
+            Character character = null;
+            if (GameMain.Server == null)
+            {
+                ushort senderId = msg.ReadUInt16();
+                character = Entity.FindEntityByID(senderId) as Character;
+                senderName = msg.ReadString();
+            }
+            else
+            {
+                NetIncomingMessage inc = msg as NetIncomingMessage;
+                if (inc == null) return null;
+                Client sender = GameMain.Server.ConnectedClients.Find(x => x.Connection == inc.SenderConnection);
+                if (sender == null) return null;
+                character = sender.Character;
+                if (character != null)
+                {
+                    senderName = character.Name;
+                }
+                else
+                {
+                    senderName = sender.name;
+                }
+            }
             string text = msg.ReadString();
 
-            return new ChatMessage(senderName, text, type, Entity.FindEntityByID(senderId) as Character);
+            return new ChatMessage(senderName, text, type, character);
         }
     }
 }

Subsurface/Source/Networking/GameServer.cs

@@ -1443,6 +1443,7 @@ namespace Barotrauma.Networking
         {
             Client sender = connectedClients.Find(x => x.Connection == inc.SenderConnection);
             ChatMessage message = ChatMessage.ReadNetworkMessage(inc);
+            if (message == null) return;
 
             List<Client> recipients = new List<Client>();
 

Subsurface/Source/Networking/NetworkMember.cs

@@ -309,6 +309,7 @@ namespace Barotrauma.Networking
                 ((chatBox.CountChildren % 2) == 0) ? Color.Transparent : Color.Black * 0.1f, message.Color,
                 Alignment.Left, null, null, true);
             msg.Font = GUI.SmallFont;
+            msg.UserData = message.SenderName;
 
             msg.Padding = new Vector4(20.0f, 0, 0, 0);
 

Subsurface/Source/Screens/NetLobbyScreen.cs

@@ -989,6 +989,7 @@ namespace Barotrauma
                 ((chatBox.CountChildren % 2) == 0) ? Color.Transparent : Color.Black*0.1f, message.Color, 
                 Alignment.Left, GUI.Style, null, true);
             msg.Font = GUI.SmallFont;
+            msg.UserData = message.SenderName;
             msg.CanBeFocused = false;
 
             msg.Padding = new Vector4(20, 0, 0, 0);