Block sketchy head items and blocks

2016-07-10 10:45:05 -05:00 · 2016-07-10 10:45:05 -05:00 · aea3ab11ab
Commit aea3ab11ab
--- a/Spigot-Server-Patches/0166-Block-sketchy-heads.patch
+++ b/Spigot-Server-Patches/0166-Block-sketchy-heads.patch
@ -0,0 +1,122 @@
+From efa5bad0e1fffbffdea0b131524edb1d2054d6b7 Mon Sep 17 00:00:00 2001
+From: Zach Brown <zach.brown@destroystokyo.com>
+Date: Sat, 9 Jul 2016 20:00:28 -0500
+Subject: [PATCH] Block sketchy heads
+
+Checks for, and blocks, sketchy creative mode spawned, heads.
+Currently only checks for new data, could be added to check all data if needed.
+This is an NMS-port of the work done here: https://github.com/MylesIsCool/SkullExploitPatch by MylesIsCool (_MylesC)
+
+diff --git a/src/main/java/com/destroystokyo/paper/ItemFilter.java b/src/main/java/com/destroystokyo/paper/ItemFilter.java
+new file mode 100644
+index 0000000..9266c19
+--- /dev/null
+++ b/src/main/java/com/destroystokyo/paper/ItemFilter.java
+@@ -0,0 +1,84 @@
+package com.destroystokyo.paper;
+
+import net.minecraft.server.*;
+
+import javax.annotation.Nullable;
+
+public class ItemFilter {
+
+    /**
+     * Checks if the ItemStack passed could be a sketchy head item or block
+     * @param itemStackIn the ItemStack to check
+     * @return whether the item is safe or sketchy
+     */
+    public static boolean isHeadSketchy(@Nullable ItemStack itemStackIn) {
+        if (itemStackIn != null && itemStackIn.getTag() != null) {
+            NBTTagCompound itemTag = itemStackIn.getTag();
+            if (Item.getId(itemStackIn.getItem()) == Item.getId(Items.SKULL) && itemStackIn.getData() == 3) {
+                return isHeadItemSketchy(itemTag);
+            } else if (Item.getId(itemStackIn.getItem()) == Block.getId(Blocks.SKULL)) {
+                return isHeadBlockSketchy(itemTag);
+            }
+
+            // If we can't figure out which is which just run it through both
+            return isHeadItemSketchy(itemTag) || isHeadBlockSketchy(itemTag);
+        }
+        return false;
+    }
+
+    /**
+     * Checks the NBTTagCompound for sketchy data, from the perspective of an Item
+     * @param nbtTagCompound NBTTagCompound from an Item
+     * @return whether the data is safe or sketchy
+     */
+    private static boolean isHeadItemSketchy(NBTTagCompound nbtTagCompound) {
+        if (nbtTagCompound.hasKey("SkullOwner")) {
+            NBTTagCompound skullOwner = nbtTagCompound.getCompound("SkullOwner");
+            if (skullOwner.hasKey("Properties")) {
+                return isHeadNBTSketchy(skullOwner.getCompound("Properties"));
+            }
+        }
+        return false;
+    }
+
+    /**
+     * Checks the NBTTagCompound for sketchy data, from the perspective of a Block
+     * @param nbtTagCompound NBTTagCompound from a Block
+     * @return whether the data is safe or sketchy
+     */
+    private static boolean isHeadBlockSketchy(NBTTagCompound nbtTagCompound) {
+        if (nbtTagCompound.hasKey("Owner")) {
+            NBTTagCompound skullOwner = nbtTagCompound.getCompound("Owner");
+            if (skullOwner.hasKey("Properties")) {
+                return isHeadNBTSketchy(skullOwner.getCompound("Properties"));
+            }
+        }
+        return false;
+    }
+
+    /**
+     * Generified checker for use in both Items and Blocks after some semantics
+     * are done above in the calling methods.
+     * @param properties The generified properties compound from a parent-compound
+     * @return whether the data is safe or sketchy
+     */
+    private static boolean isHeadNBTSketchy(NBTTagCompound properties) {
+        if (properties.hasKey("textures")) {
+            NBTTagList textures = properties.getList("textures", 10);
+            for (NBTBase texture : textures.list) {
+                if (texture instanceof NBTTagCompound) {
+                    if (!((NBTTagCompound) texture).hasKey("Signature")) {
+                        // Check
+                        if (((NBTTagCompound) texture).hasKey("Value")) {
+                            if (((NBTTagCompound) texture).getString("Value").trim().length() > 0) {
+                                return false;
+                            }
+                        }
+                        return true;
+                    }
+                }
+            }
+        }
+        return false;
+    }
+}
+diff --git a/src/main/java/net/minecraft/server/PlayerConnection.java b/src/main/java/net/minecraft/server/PlayerConnection.java
+index 85c62cd..0b1e089 100644
+--- a/src/main/java/net/minecraft/server/PlayerConnection.java
+++ b/src/main/java/net/minecraft/server/PlayerConnection.java
+@@ -2028,6 +2028,15 @@ public class PlayerConnection implements PacketListenerPlayIn, ITickable {
+                 }
+             }
+ 
+            // Paper start - Block sketchy heads
+            if (itemstack != null && (Item.getId(itemstack.getItem()) == Item.getId(Items.SKULL) && itemstack.getData() == 3 || Item.getId(itemstack.getItem()) == Block.getId(Blocks.SKULL))) {
+                if (com.destroystokyo.paper.ItemFilter.isHeadSketchy(itemstack)) {
+                    this.disconnect("Bad creative item!");
+                    return;
+                }
+            }
+            // Paper end
+
+             boolean flag1 = packetplayinsetcreativeslot.a() >= 1 && packetplayinsetcreativeslot.a() <= 45;
+             // CraftBukkit - Add invalidItems check
+             boolean flag2 = itemstack == null || itemstack.getItem() != null && (!invalidItems.contains(Item.getId(itemstack.getItem())) || !org.spigotmc.SpigotConfig.filterCreativeItems); // Spigot
+-- 
+2.9.0
+