Allow enabling sand duping (#10191)

Because this exploit has been widely known for years and has not been fixed by Mojang, we decided that it was worth allowing people to toggle it on/off due to how easy it is to make it configurable.

It should be noted that this decision does not promise all future exploits will be configurable. 

1 files changed, 28 insertions, 0 deletions

diff --git a/patches/server/0501-Configurable-max-leash-distance.patch b/patches/server/0501-Configurable-max-leash-distance.patch
new file mode 100644
index 0000000000..99a4a50ca9
--- /dev/null
+++ b/patches/server/0501-Configurable-max-leash-distance.patch
@@ -0,0 +1,28 @@
+From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
+From: Jake Potrebic <[email protected]>
+Date: Sun, 3 Jan 2021 21:04:03 -0800
+Subject: [PATCH] Configurable max leash distance
+
+
+diff --git a/src/main/java/net/minecraft/world/entity/PathfinderMob.java b/src/main/java/net/minecraft/world/entity/PathfinderMob.java
+index 5e9cf929674888b3a143a0691dc6936b304467f1..85a9bcbd229b56317c2de15670a04c6d0eb51e18 100644
+--- a/src/main/java/net/minecraft/world/entity/PathfinderMob.java
++++ b/src/main/java/net/minecraft/world/entity/PathfinderMob.java
+@@ -55,7 +55,7 @@ public abstract class PathfinderMob extends Mob {
+             float f = this.distanceTo(entity);
+ 
+             if (this instanceof TamableAnimal && ((TamableAnimal) this).isInSittingPose()) {
+-                if (f > 10.0F) {
++                if (f > entity.level().paperConfig().misc.maxLeashDistance) { // Paper - Configurable max leash distance
+                     this.level().getCraftServer().getPluginManager().callEvent(new EntityUnleashEvent(this.getBukkitEntity(), EntityUnleashEvent.UnleashReason.DISTANCE)); // CraftBukkit
+                     this.dropLeash(true, true);
+                 }
+@@ -64,7 +64,7 @@ public abstract class PathfinderMob extends Mob {
+             }
+ 
+             this.onLeashDistance(f);
+-            if (f > 10.0F) {
++            if (f > entity.level().paperConfig().misc.maxLeashDistance) { // Paper - Configurable max leash distance
+                 this.level().getCraftServer().getPluginManager().callEvent(new EntityUnleashEvent(this.getBukkitEntity(), EntityUnleashEvent.UnleashReason.DISTANCE)); // CraftBukkit
+                 this.dropLeash(true, true);
+                 this.goalSelector.disableControlFlag(Goal.Flag.MOVE);