From 4944ee3144f14f92dc1b25527a62ab259c71c2bb Mon Sep 17 00:00:00 2001
From: Patrikkk <patrikveres@hotmail.com>
Date: Mon, 1 Jun 2020 12:59:40 +0200
Subject: [PATCH] Implement Handler.LandGolfBalInCupHandler and handle packet 
 exploits.

Added multiple checks to prevent clients from sending the golfball packet directly, without having golf play actions.
---
 TShockAPI/Bouncer.cs                          |   4 +
 .../Handlers/LandGolfBallInCupHandler.cs      | 115 ++++++++++++++++++
 TShockAPI/TShockAPI.csproj                    |   1 +
 3 files changed, 120 insertions(+)
 create mode 100644 TShockAPI/Handlers/LandGolfBallInCupHandler.cs

diff --git a/TShockAPI/Bouncer.cs b/TShockAPI/Bouncer.cs
index 395bfddd..7cf7b87f 100644
--- a/TShockAPI/Bouncer.cs
+++ b/TShockAPI/Bouncer.cs
@@ -37,6 +37,7 @@ namespace TShockAPI
 	internal sealed class Bouncer
 	{
 		internal Handlers.SendTileSquareHandler STSHandler { get; set; }
+		internal Handlers.LandGolfBallInCupHandler LandGolfBallInCupHandler { get; set; }
 
 		/// <summary>Constructor call initializes Bouncer and related functionality.</summary>
 		/// <returns>A new Bouncer.</returns>
@@ -45,6 +46,9 @@ namespace TShockAPI
 			STSHandler = new Handlers.SendTileSquareHandler();
 			GetDataHandlers.SendTileSquare += STSHandler.OnReceiveSendTileSquare;
 
+			LandGolfBallInCupHandler = new Handlers.LandGolfBallInCupHandler();
+			GetDataHandlers.LandGolfBallInCup += LandGolfBallInCupHandler.OnLandGolfBallInCup;
+
 			// Setup hooks
 			GetDataHandlers.GetSection += OnGetSection;
 			GetDataHandlers.PlayerUpdate += OnPlayerUpdate;
diff --git a/TShockAPI/Handlers/LandGolfBallInCupHandler.cs b/TShockAPI/Handlers/LandGolfBallInCupHandler.cs
new file mode 100644
index 00000000..4ab7cbc9
--- /dev/null
+++ b/TShockAPI/Handlers/LandGolfBallInCupHandler.cs
@@ -0,0 +1,115 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+using System.Threading.Tasks;
+using Terraria;
+using Terraria.ID;
+
+namespace TShockAPI.Handlers
+{
+	/// <summary>
+	/// Handles client side exploits of LandGolfBallInCup packet.
+	/// </summary>
+	public class LandGolfBallInCupHandler
+	{
+		/// <summary>
+		/// List of golf ball projectile IDs.
+		/// </summary>
+		public static readonly List<int> GolfBallProjectileIDs = new List<int>()
+		{
+			ProjectileID.DirtGolfBall,
+			ProjectileID.GolfBallDyedBlack,
+			ProjectileID.GolfBallDyedBlue,
+			ProjectileID.GolfBallDyedBrown,
+			ProjectileID.GolfBallDyedCyan,
+			ProjectileID.GolfBallDyedGreen,
+			ProjectileID.GolfBallDyedLimeGreen,
+			ProjectileID.GolfBallDyedOrange,
+			ProjectileID.GolfBallDyedPink,
+			ProjectileID.GolfBallDyedPurple,
+			ProjectileID.GolfBallDyedRed,
+			ProjectileID.GolfBallDyedSkyBlue,
+			ProjectileID.GolfBallDyedTeal,
+			ProjectileID.GolfBallDyedViolet,
+			ProjectileID.GolfBallDyedYellow
+		};
+
+		/// <summary>
+		/// List of golf club item IDs
+		/// </summary>
+		public static readonly List<int> GolfClubItemIDs = new List<int>()
+		{
+			ItemID.GolfClubChlorophyteDriver,
+			ItemID.GolfClubDiamondWedge,
+			ItemID.GolfClubShroomitePutter,
+			ItemID.Fake_BambooChest,
+			ItemID.GolfClubTitaniumIron,
+			ItemID.GolfClubGoldWedge,
+			ItemID.GolfClubLeadPutter,
+			ItemID.GolfClubMythrilIron,
+			ItemID.GolfClubWoodDriver,
+			ItemID.GolfClubBronzeWedge,
+			ItemID.GolfClubRustyPutter,
+			ItemID.GolfClubStoneIron,
+			ItemID.GolfClubPearlwoodDriver,
+			ItemID.GolfClubIron,
+			ItemID.GolfClubDriver,
+			ItemID.GolfClubWedge,
+			ItemID.GolfClubPutter
+		};
+
+		/// <summary>
+		/// Invoked when a player lands a golf ball in a cup.
+		/// </summary>
+		/// <param name="sender"></param>
+		/// <param name="args"></param>
+		public void OnLandGolfBallInCup(object sender, GetDataHandlers.LandGolfBallInCupEventArgs args)
+		{
+			if (args.PlayerIndex != args.Player.Index)
+			{
+				TShock.Log.ConsoleError($"LandGolfBallInCupHandler: Packet is spoofing to be player ID {args.PlayerIndex}! - From [{args.Player.Index}]{args.Player.Name}");
+				args.Handled = true;
+				return;
+			}
+
+			if (args.TileX > Main.maxTilesX || args.TileX < 0
+			   || args.TileY > Main.maxTilesY || args.TileY < 0)
+			{
+				TShock.Log.ConsoleError($"LandGolfBallInCupHandler: X and Y position is out of world bounds! - From {args.Player.Name}");
+				args.Handled = true;
+				return;
+			}
+
+			if (!Main.tile[args.TileX, args.TileY].active() && Main.tile[args.TileX, args.TileY].type != TileID.GolfHole)
+			{
+				TShock.Log.ConsoleError($"LandGolfBallInCupHandler: Tile at packet position X:{args.TileX} Y:{args.TileY} is not a golf hole! - From {args.Player.Name}");
+				args.Handled = true;
+				return;
+			}
+
+			if (!GolfBallProjectileIDs.Contains(args.ProjectileType))
+			{
+				TShock.Log.ConsoleError($"LandGolfBallInCupHandler: Invalid golf ball projectile ID {args.ProjectileType}! - From {args.Player.Name}");
+				args.Handled = true;
+				return;
+			}
+
+			var usedGolfBall = args.Player.RecentlyCreatedProjectiles.Any(e => GolfBallProjectileIDs.Contains(e.Type));
+			var usedGolfClub = args.Player.RecentlyCreatedProjectiles.Any(e => e.Type == ProjectileID.GolfClubHelper);
+			if (!usedGolfClub && !usedGolfBall)
+			{
+				TShock.Log.ConsoleError($"GolfPacketHandler: Player did not have create a golf club projectile the last 5 seconds! - From {args.Player.Name}");
+				args.Handled = true;
+				return;
+			}
+
+			if (!GolfClubItemIDs.Contains(args.Player.SelectedItem.type))
+			{
+				TShock.Log.ConsoleError($"LandGolfBallInCupHandler: Item selected is not a golf club! - From {args.Player.Name}");
+				args.Handled = true;
+				return;
+			}
+		}
+	}
+}
diff --git a/TShockAPI/TShockAPI.csproj b/TShockAPI/TShockAPI.csproj
index ea6f4f48..fedc3f0b 100644
--- a/TShockAPI/TShockAPI.csproj
+++ b/TShockAPI/TShockAPI.csproj
@@ -88,6 +88,7 @@
     <Compile Include="DB\ResearchDatastore.cs" />
     <Compile Include="DB\TileManager.cs" />
     <Compile Include="Extensions\ExceptionExt.cs" />
+    <Compile Include="Handlers\LandGolfBallInCupHandler.cs" />
     <Compile Include="Handlers\SendTileSquareHandler.cs" />
     <Compile Include="Hooks\AccountHooks.cs" />
     <Compile Include="Hooks\GeneralHooks.cs" />