Scissors/patches/server/0034-Prevent-crash-paintings-and-similar-entity-OOB-explo.patch

From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
From: Allink <arclicious@vivaldi.net>
Date: Tue, 17 May 2022 06:31:37 +0100
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/PositionUtility.java b/src/main/java/com/github/atlasmediagroup/scissors/PositionUtility.java
new file mode 100644
index 0000000000000000000000000000000000000000..b5b2f9af376940dc662cc7b57485e93a9c7ce96d
--- /dev/null
+++ b/src/main/java/com/github/atlasmediagroup/scissors/PositionUtility.java
@@ -0,0 +1,84 @@
+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 07f04c1708b118ace3ed73ae2bf88c29b1c80ad2..bc21918595f5ac4a62d96dfb81ed75e9d8000eb0 100644
--- a/src/main/java/net/minecraft/world/entity/Entity.java
+++ b/src/main/java/net/minecraft/world/entity/Entity.java
@@ -1,30 +1,10 @@
 package net.minecraft.world.entity;
 
-import com.google.common.collect.ImmutableList;
-import com.google.common.collect.Iterables;
-import com.google.common.collect.Lists;
-import com.google.common.collect.Sets;
-import com.google.common.collect.UnmodifiableIterator;
+import com.github.atlasmediagroup.scissors.PositionUtility;
+import com.google.common.collect.*;
 import it.unimi.dsi.fastutil.objects.Object2DoubleArrayMap;
 import it.unimi.dsi.fastutil.objects.Object2DoubleMap;
-import java.util.Arrays;
-import java.util.Collections;
-import java.util.Iterator;
-import java.util.List;
-import java.util.Locale;
-import java.util.Optional;
-import java.util.Random;
-import java.util.Set;
-import java.util.UUID;
-import java.util.concurrent.atomic.AtomicInteger;
-import java.util.function.Predicate;
-import java.util.stream.Stream;
-import javax.annotation.Nullable;
-import net.minecraft.BlockUtil;
-import net.minecraft.CrashReport;
-import net.minecraft.CrashReportCategory;
-import net.minecraft.ReportedException;
-import net.minecraft.Util;
+import net.minecraft.*;
 import net.minecraft.advancements.CriteriaTriggers;
 import net.minecraft.commands.CommandSource;
 import net.minecraft.commands.CommandSourceStack;
@@ -34,11 +14,7 @@ import net.minecraft.core.Direction;
 import net.minecraft.core.Vec3i;
 import net.minecraft.core.particles.BlockParticleOption;
 import net.minecraft.core.particles.ParticleTypes;
-import net.minecraft.nbt.CompoundTag;
-import net.minecraft.nbt.DoubleTag;
-import net.minecraft.nbt.FloatTag;
-import net.minecraft.nbt.ListTag;
-import net.minecraft.nbt.StringTag;
+import net.minecraft.nbt.*;
 import net.minecraft.network.chat.ClickEvent;
 import net.minecraft.network.chat.Component;
 import net.minecraft.network.chat.HoverEvent;
@@ -77,22 +53,8 @@ import net.minecraft.world.entity.vehicle.Boat;
 import net.minecraft.world.item.ItemStack;
 import net.minecraft.world.item.enchantment.EnchantmentHelper;
 import net.minecraft.world.item.enchantment.ProtectionEnchantment;
-import net.minecraft.world.level.BlockGetter;
-import net.minecraft.world.level.ChunkPos;
-import net.minecraft.world.level.ClipContext;
-import net.minecraft.world.level.Explosion;
-import net.minecraft.world.level.GameRules;
-import net.minecraft.world.level.ItemLike;
-import net.minecraft.world.level.Level;
-import net.minecraft.world.level.LevelReader;
-import net.minecraft.world.level.block.Block;
-import net.minecraft.world.level.block.Blocks;
-import net.minecraft.world.level.block.FenceGateBlock;
-import net.minecraft.world.level.block.HoneyBlock;
-import net.minecraft.world.level.block.Mirror;
-import net.minecraft.world.level.block.RenderShape;
-import net.minecraft.world.level.block.Rotation;
-import net.minecraft.world.level.block.SoundType;
+import net.minecraft.world.level.*;
+import net.minecraft.world.level.block.*;
 import net.minecraft.world.level.block.state.BlockState;
 import net.minecraft.world.level.block.state.properties.BlockStateProperties;
 import net.minecraft.world.level.border.WorldBorder;
@@ -119,34 +81,33 @@ import net.minecraft.world.scores.PlayerTeam;
 import net.minecraft.world.scores.Team;
 import org.apache.logging.log4j.LogManager;
 import org.apache.logging.log4j.Logger;
-
-// CraftBukkit start
 import org.bukkit.Bukkit;
 import org.bukkit.Location;
 import org.bukkit.Server;
 import org.bukkit.block.BlockFace;
 import org.bukkit.command.CommandSender;
+import org.bukkit.craftbukkit.CraftWorld;
+import org.bukkit.craftbukkit.entity.CraftEntity;
+import org.bukkit.craftbukkit.entity.CraftPlayer;
+import org.bukkit.craftbukkit.event.CraftEventFactory;
 import org.bukkit.craftbukkit.event.CraftPortalEvent;
 import org.bukkit.entity.Hanging;
 import org.bukkit.entity.LivingEntity;
+import org.bukkit.entity.Pose;
 import org.bukkit.entity.Vehicle;
-import org.bukkit.event.entity.EntityCombustByEntityEvent;
+import org.bukkit.event.entity.*;
 import org.bukkit.event.hanging.HangingBreakByEntityEvent;
+import org.bukkit.event.player.PlayerTeleportEvent;
 import org.bukkit.event.vehicle.VehicleBlockCollisionEvent;
 import org.bukkit.event.vehicle.VehicleEnterEvent;
 import org.bukkit.event.vehicle.VehicleExitEvent;
-import org.bukkit.craftbukkit.CraftWorld;
-import org.bukkit.craftbukkit.entity.CraftEntity;
-import org.bukkit.craftbukkit.entity.CraftPlayer;
-import org.bukkit.craftbukkit.event.CraftEventFactory;
-import org.bukkit.entity.Pose;
-import org.bukkit.event.entity.EntityAirChangeEvent;
-import org.bukkit.event.entity.EntityCombustEvent;
-import org.bukkit.event.entity.EntityDropItemEvent;
-import org.bukkit.event.entity.EntityPortalEvent;
-import org.bukkit.event.entity.EntityPoseChangeEvent;
-import org.bukkit.event.player.PlayerTeleportEvent;
 import org.bukkit.plugin.PluginManager;
+
+import javax.annotation.Nullable;
+import java.util.*;
+import java.util.concurrent.atomic.AtomicInteger;
+import java.util.function.Predicate;
+import java.util.stream.Stream;
 // CraftBukkit end
 
 public abstract class Entity implements Nameable, EntityAccess, CommandSource, net.minecraft.server.KeyedObject { // Paper
@@ -1753,26 +1714,41 @@ public abstract class Entity implements Nameable, EntityAccess, CommandSource, n
         this.yo = y;
         this.zo = d4;
         this.setPos(d3, y, d4);
-        if (this.valid) this.level.getChunk((int) Math.floor(this.getX()) >> 4, (int) Math.floor(this.getZ()) >> 4); // CraftBukkit
+        if (this.valid)
+            this.level.getChunk((int) Math.floor(this.getX()) >> 4, (int) Math.floor(this.getZ()) >> 4); // CraftBukkit
     }
 
-    public void moveTo(Vec3 pos) {
+    public void moveTo(Vec3 pos)
+    {
         this.moveTo(pos.x, pos.y, pos.z);
     }
 
-    public void moveTo(double x, double y, double z) {
+    public void moveTo(double x, double y, double z)
+    {
         this.moveTo(x, y, z, this.getYRot(), this.getXRot());
     }
 
-    public void moveTo(BlockPos pos, float yaw, float pitch) {
+    public void moveTo(BlockPos pos, float yaw, float pitch)
+    {
         this.moveTo((double) pos.getX() + 0.5D, (double) pos.getY(), (double) pos.getZ() + 0.5D, yaw, pitch);
     }
 
-    public void moveTo(double x, double y, double z, float yaw, float pitch) {
+    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) {
+        if (!preserveMotion)
+        {
             this.deltaMovement = Vec3.ZERO;
-        } else {
+        }
+        else
+        {
             this.preserveMotion = false;
         }
         // Paper end
@@ -3161,28 +3137,39 @@ public abstract class Entity implements Nameable, EntityAccess, CommandSource, n
     }
 
     @Nullable
-    public Entity teleportTo(ServerLevel worldserver, BlockPos location) {
+    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) {
+        if (!isAlive() || !valid)
+        {
             LOGGER.warn("Illegal Entity Teleport " + this + " to " + worldserver + ":" + location, new Throwable());
             return null;
         }
         // Paper end
-        if (this.level instanceof ServerLevel && !this.isRemoved()) {
+        if (this.level instanceof ServerLevel && !this.isRemoved())
+        {
             this.level.getProfiler().push("changeDimension");
             // CraftBukkit start
             // this.decouple();
-            if (worldserver == null) {
+            if (worldserver == null)
+            {
                 return null;
             }
             // CraftBukkit end
             this.level.getProfiler().push("reposition");
             PortalInfo shapedetectorshape = (location == null) ? this.findDimensionEntryPoint(worldserver) : new PortalInfo(new Vec3(location.getX(), location.getY(), location.getZ()), Vec3.ZERO, this.yRot, this.xRot, worldserver, null); // CraftBukkit
 
-            if (shapedetectorshape == null) {
+            if (shapedetectorshape == null)
+            {
                 return null;
-            } else {
+            }
+            else
+            {
                 // CraftBukkit start
                 worldserver = shapedetectorshape.world;
 
@@ -4028,11 +4015,20 @@ public abstract class Entity implements Nameable, EntityAccess, CommandSource, n
         // Paper start
         this.setPosRaw(x, y, z, false);
     }
-    public final void setPosRaw(double x, double y, double z, boolean forceBoundingBoxUpdate) {
+    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;
+
         // Paper end
         // Paper start - fix MC-4
-        if (this instanceof ItemEntity) {
-            if (com.destroystokyo.paper.PaperConfig.fixEntityPositionDesync) {
+        if (this instanceof ItemEntity)
+        {
+            if (com.destroystokyo.paper.PaperConfig.fixEntityPositionDesync)
+            {
                 // encode/decode from PacketPlayOutEntity
                 x = Mth.lfloor(x * 4096.0D) * (1 / 4096.0D);
                 y = Mth.lfloor(y * 4096.0D) * (1 / 4096.0D);
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 ca9decf85dd1af0baf0d34a48aa67cbb9f4eb586..53cd0dcb94c2cc2278e719235fb470535b7094e4 100644
--- a/src/main/java/net/minecraft/world/entity/decoration/HangingEntity.java
+++ b/src/main/java/net/minecraft/world/entity/decoration/HangingEntity.java
@@ -1,7 +1,6 @@
 package net.minecraft.world.entity.decoration;
 
-import java.util.function.Predicate;
-import javax.annotation.Nullable;
+import com.github.atlasmediagroup.scissors.PositionUtility;
 import net.minecraft.core.BlockPos;
 import net.minecraft.core.Direction;
 import net.minecraft.nbt.CompoundTag;
@@ -16,7 +15,6 @@ import net.minecraft.world.entity.MoverType;
 import net.minecraft.world.entity.item.ItemEntity;
 import net.minecraft.world.entity.player.Player;
 import net.minecraft.world.item.ItemStack;
-import org.apache.commons.lang3.Validate;
 import net.minecraft.world.level.Level;
 import net.minecraft.world.level.block.DiodeBlock;
 import net.minecraft.world.level.block.Mirror;
@@ -25,9 +23,13 @@ import net.minecraft.world.level.block.state.BlockState;
 import net.minecraft.world.level.material.Material;
 import net.minecraft.world.phys.AABB;
 import net.minecraft.world.phys.Vec3;
+import org.apache.commons.lang3.Validate;
 import org.bukkit.entity.Hanging;
 import org.bukkit.event.hanging.HangingBreakByEntityEvent;
 import org.bukkit.event.hanging.HangingBreakEvent;
+
+import javax.annotation.Nullable;
+import java.util.function.Predicate;
 // CraftBukkit end
 
 public abstract class HangingEntity extends Entity {
@@ -264,8 +266,11 @@ 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"));
+    public void readAdditionalSaveData(CompoundTag nbt)
+    {
+        // 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();
@@ -291,8 +296,11 @@ public abstract class HangingEntity extends Entity {
     }
 
     @Override
-    public void setPos(double x, double y, double z) {
-        this.pos = new BlockPos(x, y, z);
+    public void setPos(double x, double y, double z)
+    {
+        // Scissors start - Fix this stupid bullshit
+        this.pos = PositionUtility.getValidBlockPos(new BlockPos(x, y, z), this);
+        // Scissors end
         this.recalculateBoundingBox();
         this.hasImpulse = true;
     }