From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
From: William Blake Galbreath <blake.galbreath@gmail.com>
Date: Fri, 30 Jul 2021 03:42:00 -0500
Subject: [PATCH] Fix #533 crash exploit

This fixes an exploit where a player can drop a map item with an invalid id to crash the server

diff --git a/src/main/java/net/minecraft/world/entity/player/Player.java b/src/main/java/net/minecraft/world/entity/player/Player.java
index e90193b303ecafc1073d22ff0e145a6fef42c4ce..c11f7a76576710b751a09d0a916017f732b09003 100644
--- a/src/main/java/net/minecraft/world/entity/player/Player.java
+++ b/src/main/java/net/minecraft/world/entity/player/Player.java
@@ -808,6 +808,7 @@ public abstract class Player extends LivingEntity {
             // Paper start - remove player from map on drop
             if (stack.getItem() == Items.FILLED_MAP) {
                 MapItemSavedData worldmap = MapItem.getSavedData(stack, this.level);
+                if (worldmap != null) // Purpur - fix #533
                 worldmap.tickCarriedBy(this, stack);
             }
             // Paper end