Implementing SyncTilePickingHandler. Patching tile damage related exploits.

With this packet, players could kick all players by sending invalid world position data.

TShockAPI/Handlers/SyncTilePickingHandler.cs

@@ -0,0 +1,36 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+using System.Threading.Tasks;
+using Terraria;
+using static TShockAPI.GetDataHandlers;
+
+namespace TShockAPI.Handlers
+{
+	class SyncTilePickingHandler : IPacketHandler<SyncTilePickingEventArgs>
+	{
+		/// <summary>
+		/// Invoked when player damages a tile.
+		/// </summary>
+		/// <param name="sender"></param>
+		/// <param name="args"></param>
+		public void OnReceive(object sender, SyncTilePickingEventArgs args)
+		{
+			if (args.PlayerIndex != args.Player.Index)
+			{
+				TShock.Log.ConsoleDebug($"SyncTilePickingHandler: SyncTilePicking packet rejected for ID spoofing. Expected {args.Player.Index}, received {args.PlayerIndex} from {args.Player.Name}.");
+				args.Handled = true;
+				return;
+			}
+
+			if (args.TileX > Main.maxTilesX || args.TileX < 0
+			   || args.TileY > Main.maxTilesY || args.TileY < 0)
+			{
+				TShock.Log.ConsoleDebug($"SyncTilePickingHandler: X and Y position is out of world bounds! - From {args.Player.Name}");
+				args.Handled = true;
+				return;
+			}
+		}
+	}
+}