Scissors/patches/server/0032-Prevent-crash-paintings-and-similar-entity-OOB-explo.patch

From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
From: Telesphoreo <me@telesphoreo.me>
Date: Sun, 22 May 2022 21:15:51 -0500
Subject: [PATCH] Prevent crash paintings and similar entity OOB exploits


diff --git a/src/main/java/com/github/atlasmediagroup/scissors/MathUtility.java b/src/main/java/com/github/atlasmediagroup/scissors/MathUtility.java
new file mode 100644
index 0000000000000000000000000000000000000000..7965cf3abd02d415dd0e71a0de73987e5fdf11ec
--- /dev/null
+++ b/src/main/java/com/github/atlasmediagroup/scissors/MathUtility.java
@@ -0,0 +1,29 @@
+package com.github.atlasmediagroup.scissors;
+
+public class MathUtility
+{
+    public static int clampInt(int number, int minimum, int maximum)
+    {
+        return Math.min(Math.max(number, minimum), maximum);
+    }
+
+    public static long clampLong(long number, long minimum, long maximum)
+    {
+        return Math.min(Math.max(number, minimum), maximum);
+    }
+
+    public static double clampDouble(double number, double minimum, double maximum)
+    {
+        return Math.min(Math.max(number, minimum), maximum);
+    }
+
+    public static int safeDoubleToInt(double number)
+    {
+        return (int) clampDouble(number, Integer.MIN_VALUE, Integer.MAX_VALUE);
+    }
+
+    public static int safeLongToInt(long number)
+    {
+        return (int) clampLong(number, Integer.MIN_VALUE, Integer.MAX_VALUE);
+    }
+}
diff --git a/src/main/java/com/github/atlasmediagroup/scissors/NbtUtility.java b/src/main/java/com/github/atlasmediagroup/scissors/NbtUtility.java
index 978cb98c81195640fb3704d2077148f2be0dca36..59a4ff3593e74f72c3843554c2e14b82912c0a54 100644
--- a/src/main/java/com/github/atlasmediagroup/scissors/NbtUtility.java
+++ b/src/main/java/com/github/atlasmediagroup/scissors/NbtUtility.java
@@ -1,13 +1,9 @@
 package com.github.atlasmediagroup.scissors;
 
-import com.google.common.base.Strings;
-import com.google.common.collect.Lists;
 import net.minecraft.nbt.*;
 
 import javax.annotation.Nullable;
 import java.nio.charset.StandardCharsets;
-import java.util.Collections;
-import java.util.List;
 
 public class NbtUtility
 {
diff --git a/src/main/java/com/github/atlasmediagroup/scissors/PositionUtility.java b/src/main/java/com/github/atlasmediagroup/scissors/PositionUtility.java
new file mode 100644
index 0000000000000000000000000000000000000000..fd22a200e070ca5a594802d2f201c6b27d6cddcf
--- /dev/null
+++ b/src/main/java/com/github/atlasmediagroup/scissors/PositionUtility.java
@@ -0,0 +1,83 @@
+package com.github.atlasmediagroup.scissors;
+
+import net.minecraft.core.BlockPos;
+import net.minecraft.world.entity.Entity;
+import net.minecraft.world.level.Level;
+import net.minecraft.world.level.border.WorldBorder;
+import net.minecraft.world.phys.Vec3;
+
+public class PositionUtility
+{
+    public static Vec3 getValidVec3(double x, double y, double z, Entity entity)
+    {
+        final Level level = entity.level;
+
+        try
+        {
+            if (level.isInWorldBounds(new BlockPos(Math.floor(MathUtility.safeDoubleToInt(x)), Math.floor(MathUtility.safeDoubleToInt(y)), Math.floor(MathUtility.safeDoubleToInt(z)))))
+            {
+                return new Vec3(x, y, z);
+            }
+            else
+            {
+                final WorldBorder worldBorder = level.getWorldBorder();
+
+                final double maxX = worldBorder.getMaxX();
+                final double maxY = level.getMaxBuildHeight();
+                final double maxZ = worldBorder.getMaxZ();
+
+                final double minX = worldBorder.getMinX();
+                final double minY = level.getMinBuildHeight();
+                final double minZ = worldBorder.getMinZ();
+
+                return new Vec3(MathUtility.clampDouble(x, minX, maxX), MathUtility.clampDouble(y, minY, maxY), MathUtility.clampDouble(z, minZ, maxZ));
+            }
+        }
+        catch (Exception e)
+        { // If we throw some sort of exception due to the position being crazy, catch it
+            return new Vec3(0, 0, 0);
+        }
+    }
+
+    public static Vec3 getValidVec3FromBlockPos(BlockPos blockPos, Entity entity)
+    {
+        final BlockPos validBlockPos = getValidBlockPos(blockPos, entity);
+
+        return new Vec3(validBlockPos.getX(), validBlockPos.getY(), validBlockPos.getZ());
+    }
+
+    public static BlockPos getValidBlockPos(BlockPos blockPos, Entity entity)
+    {
+        final Level level = entity.level;
+
+        try
+        {
+            if (level.isInWorldBounds(blockPos))
+            {
+                return blockPos;
+            }
+            else
+            {
+                final int x = blockPos.getX();
+                final int y = blockPos.getY();
+                final int z = blockPos.getZ();
+
+                final WorldBorder worldBorder = level.getWorldBorder();
+
+                final int maxX = MathUtility.safeDoubleToInt(worldBorder.getMaxX());
+                final int maxY = level.getMaxBuildHeight();
+                final int maxZ = MathUtility.safeDoubleToInt(worldBorder.getMaxZ());
+
+                final int minX = MathUtility.safeDoubleToInt(worldBorder.getMinX());
+                final int minY = level.getMinBuildHeight();
+                final int minZ = MathUtility.safeDoubleToInt(worldBorder.getMinZ());
+
+                return new BlockPos(MathUtility.clampInt(x, minX, maxX), MathUtility.clampInt(y, minY, maxY), MathUtility.clampInt(z, minZ, maxZ));
+            }
+        }
+        catch (Exception e)
+        { // If we throw some sort of exception due to the position being crazy, catch it
+            return new BlockPos(0, 0, 0);
+        }
+    }
+}
diff --git a/src/main/java/net/minecraft/world/entity/Entity.java b/src/main/java/net/minecraft/world/entity/Entity.java
index bc9e6a2403d2e0d174c87f9bcb54dc4af47c610b..5fffd4f1661a20522d1bb85308901826dfaf7dd9 100644
--- a/src/main/java/net/minecraft/world/entity/Entity.java
+++ b/src/main/java/net/minecraft/world/entity/Entity.java
@@ -1,5 +1,6 @@
 package net.minecraft.world.entity;
 
+import com.github.atlasmediagroup.scissors.PositionUtility;
 import com.google.common.collect.ImmutableList;
 import com.google.common.collect.ImmutableList.Builder;
 import com.google.common.collect.Iterables;
@@ -1774,6 +1775,13 @@ public abstract class Entity implements Nameable, EntityAccess, CommandSource {
     }
 
     public void moveTo(double x, double y, double z, float yaw, float pitch) {
+        // Scissors start - Reassign x, y & z to make sure entities can't move out of the world border
+        Vec3 vec3 = PositionUtility.getValidVec3(x, y, z, this);
+        x = vec3.x;
+        y = vec3.y;
+        z = vec3.z;
+        // Scissors end
+
         // Paper - cancel entity velocity if teleported
         if (!preserveMotion) {
             this.deltaMovement = Vec3.ZERO;
@@ -3208,6 +3216,10 @@ public abstract class Entity implements Nameable, EntityAccess, CommandSource {
 
     @Nullable
     public Entity teleportTo(ServerLevel worldserver, BlockPos location) {
+        // Scissors start - Reassign location to a safe value
+        location = PositionUtility.getValidBlockPos(location, this);
+        // Scissors end
+
         // CraftBukkit end
         // Paper start - fix bad state entities causing dupes
         if (!isAlive() || !valid) {
@@ -4102,6 +4114,13 @@ public abstract class Entity implements Nameable, EntityAccess, CommandSource {
         this.setPosRaw(x, y, z, false);
     }
     public final void setPosRaw(double x, double y, double z, boolean forceBoundingBoxUpdate) {
+        // Scissors start - Reassign x, y & z to prevent entities from moving outside the world border
+        Vec3 vec = PositionUtility.getValidVec3(x, y, z, this);
+        x = vec.x;
+        y = vec.y;
+        z = vec.z;
+        // Scissors end
+
         // Paper start - block invalid positions
         if (!checkPosition(this, x, y, z)) {
             return;
diff --git a/src/main/java/net/minecraft/world/entity/decoration/HangingEntity.java b/src/main/java/net/minecraft/world/entity/decoration/HangingEntity.java
index 2805ebfe4ffe769bcde778a1225b3101c91538d8..7c988395567c170d825af2bd99121f2d4d05cd8d 100644
--- a/src/main/java/net/minecraft/world/entity/decoration/HangingEntity.java
+++ b/src/main/java/net/minecraft/world/entity/decoration/HangingEntity.java
@@ -1,5 +1,6 @@
 package net.minecraft.world.entity.decoration;
 
+import com.github.atlasmediagroup.scissors.PositionUtility;
 import java.util.function.Predicate;
 import javax.annotation.Nullable;
 import net.minecraft.core.BlockPos;
@@ -265,7 +266,9 @@ public abstract class HangingEntity extends Entity {
 
     @Override
     public void readAdditionalSaveData(CompoundTag nbt) {
-        this.pos = new BlockPos(nbt.getInt("TileX"), nbt.getInt("TileY"), nbt.getInt("TileZ"));
+        // Scissors start - Stop this stupid bullshit
+        this.pos = PositionUtility.getValidBlockPos(new BlockPos(nbt.getInt("TileX"), nbt.getInt("TileY"), nbt.getInt("TileZ")), this);
+        // Scissors end
     }
 
     public abstract int getWidth();
@@ -292,7 +295,9 @@ public abstract class HangingEntity extends Entity {
 
     @Override
     public void setPos(double x, double y, double z) {
-        this.pos = new BlockPos(x, y, z);
+        // Scissors start - Fix this stupid bullshit
+        this.pos = PositionUtility.getValidBlockPos(new BlockPos(x, y, z), this);
+        // Scissors end
         this.recalculateBoundingBox();
         this.hasImpulse = true;
     }