From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
From: Sudzzy <originmc@outlook.com>
Date: Thu, 3 Mar 2016 02:50:31 -0600
Subject: [PATCH] Configurable inter-world teleportation safety

People are able to abuse the way Bukkit handles teleportation across worlds since it provides a built in teleportation
safety check.

To abuse the safety check, players are required to get into a location deemed unsafe by Bukkit e.g. be within a chest
or door block. While they are in this block, they accept a teleport request from a player within a different world. Once
the player teleports, Minecraft will recursively search upwards for a safe location, this could eventually land within a
player's skybase.

Example setup to perform the glitch: http://puu.sh/ng3PC/cf072dcbdb.png
The wanted destination was on top of the emerald block however the player ended on top of the diamond block.
This only is the case if the player is teleporting between worlds.

diff --git a/src/main/java/com/destroystokyo/paper/PaperWorldConfig.java b/src/main/java/com/destroystokyo/paper/PaperWorldConfig.java
index 304883dc18bab3bf4740006a5e6d7c58bab12348..6d1473a5267ecd3617d76fee23527bde58283bb1 100644
--- a/src/main/java/com/destroystokyo/paper/PaperWorldConfig.java
+++ b/src/main/java/com/destroystokyo/paper/PaperWorldConfig.java
@@ -246,4 +246,9 @@ public class PaperWorldConfig {
         portalCreateRadius = getInt("portal-create-radius", 16);
         portalSearchVanillaDimensionScaling = getBoolean("portal-search-vanilla-dimension-scaling", true);
     }
+
+    public boolean disableTeleportationSuffocationCheck;
+    private void disableTeleportationSuffocationCheck() {
+        disableTeleportationSuffocationCheck = getBoolean("disable-teleportation-suffocation-check", false);
+    }
 }
diff --git a/src/main/java/org/bukkit/craftbukkit/entity/CraftPlayer.java b/src/main/java/org/bukkit/craftbukkit/entity/CraftPlayer.java
index 5a90d36915ab14aea6bf6431a1894031a5c9ee96..8eac81867ff299d45427fd71d9b085439deb95d8 100644
--- a/src/main/java/org/bukkit/craftbukkit/entity/CraftPlayer.java
+++ b/src/main/java/org/bukkit/craftbukkit/entity/CraftPlayer.java
@@ -898,7 +898,7 @@ public class CraftPlayer extends CraftHumanEntity implements Player {
         if (fromWorld == toWorld) {
             entity.connection.teleport(to);
         } else {
-            server.getHandle().moveToWorld(entity, toWorld, true, to, true);
+            server.getHandle().moveToWorld(entity, toWorld, true, to, !toWorld.paperConfig.disableTeleportationSuffocationCheck); // Paper
         }
         return true;
     }