From 2eeedfab569f31c1742aeb96a0bc4ee16c2ac7e6 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 cd47a4ca06..abbf59bb91 100644
--- a/src/main/java/com/destroystokyo/paper/PaperWorldConfig.java
+++ b/src/main/java/com/destroystokyo/paper/PaperWorldConfig.java
@@ -198,4 +198,9 @@ public class PaperWorldConfig {
         portalSearchRadius = getInt("portal-search-radius", 128);
         portalCreateRadius = getInt("portal-create-radius", 16);
     }
+
+    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 5f3b6ebbe4..5ce7504c5f 100644
--- a/src/main/java/org/bukkit/craftbukkit/entity/CraftPlayer.java
+++ b/src/main/java/org/bukkit/craftbukkit/entity/CraftPlayer.java
@@ -759,7 +759,7 @@ public class CraftPlayer extends CraftHumanEntity implements Player {
         if (fromWorld == toWorld) {
             entity.playerConnection.teleport(to);
         } else {
-            server.getHandle().moveToWorld(entity, toWorld.getWorldProvider().getDimensionManager(), true, to, true);
+            server.getHandle().moveToWorld(entity, toWorld.getWorldProvider().getDimensionManager(), true, to, !toWorld.paperConfig.disableTeleportationSuffocationCheck);
         }
         return true;
     }
-- 
2.26.2