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https://github.com/PaperMC/Paper.git
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89d51d5f29
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.
87 lines
4.7 KiB
Diff
87 lines
4.7 KiB
Diff
From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
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From: Nassim Jahnke <nassim@njahnke.dev>
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Date: Wed, 1 Dec 2021 12:36:25 +0100
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Subject: [PATCH] Prevent sending oversized item data in equipment and metadata
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diff --git a/src/main/java/net/minecraft/network/syncher/EntityDataSerializers.java b/src/main/java/net/minecraft/network/syncher/EntityDataSerializers.java
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index f9e15908143f4453c2a5817b412e8a13554553f0..06498788c169133bd563c5a87192b71802c4d4df 100644
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--- a/src/main/java/net/minecraft/network/syncher/EntityDataSerializers.java
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+++ b/src/main/java/net/minecraft/network/syncher/EntityDataSerializers.java
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@@ -42,7 +42,7 @@ public class EntityDataSerializers {
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public static final EntityDataSerializer<ItemStack> ITEM_STACK = new EntityDataSerializer<ItemStack>() {
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@Override
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public void write(FriendlyByteBuf buf, ItemStack value) {
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- buf.writeItem(value);
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+ buf.writeItem(net.minecraft.world.entity.LivingEntity.sanitizeItemStack(value, true)); // Paper - prevent oversized data
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}
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@Override
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diff --git a/src/main/java/net/minecraft/server/level/ServerEntity.java b/src/main/java/net/minecraft/server/level/ServerEntity.java
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index a83b4d9b61230ecf5f776269cab228cf49c5f546..86f6e5bad325dd3d817b643388b196121624b8c7 100644
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--- a/src/main/java/net/minecraft/server/level/ServerEntity.java
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+++ b/src/main/java/net/minecraft/server/level/ServerEntity.java
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@@ -335,7 +335,10 @@ public class ServerEntity {
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ItemStack itemstack = ((LivingEntity) this.entity).getItemBySlot(enumitemslot);
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if (!itemstack.isEmpty()) {
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- list.add(Pair.of(enumitemslot, itemstack.copy()));
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+ // Paper start - prevent oversized data
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+ final ItemStack sanitized = LivingEntity.sanitizeItemStack(itemstack.copy(), false);
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+ list.add(Pair.of(enumitemslot, sanitized));
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+ // Paper end - prevent oversized data
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}
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}
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diff --git a/src/main/java/net/minecraft/world/entity/LivingEntity.java b/src/main/java/net/minecraft/world/entity/LivingEntity.java
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index d4abce0b715d5eda99505fa0e29eeab20b538fd9..ccbafac8e5930571928e87f1c83f9f481fcfe8c4 100644
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--- a/src/main/java/net/minecraft/world/entity/LivingEntity.java
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+++ b/src/main/java/net/minecraft/world/entity/LivingEntity.java
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@@ -3208,7 +3208,10 @@ public abstract class LivingEntity extends Entity implements Attackable {
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equipmentChanges.forEach((enumitemslot, itemstack) -> {
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ItemStack itemstack1 = itemstack.copy();
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- list.add(Pair.of(enumitemslot, itemstack1));
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+ // Paper start - prevent oversized data
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+ ItemStack toSend = sanitizeItemStack(itemstack1, true);
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+ list.add(Pair.of(enumitemslot, toSend));
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+ // Paper end - prevent oversized data
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switch (enumitemslot.getType()) {
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case HAND:
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this.setLastHandItem(enumitemslot, itemstack1);
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@@ -3221,6 +3224,34 @@ public abstract class LivingEntity extends Entity implements Attackable {
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((ServerLevel) this.level()).getChunkSource().broadcast(this, new ClientboundSetEquipmentPacket(this.getId(), list));
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}
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+ // Paper start - prevent oversized data
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+ public static ItemStack sanitizeItemStack(final ItemStack itemStack, final boolean copyItemStack) {
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+ if (itemStack.isEmpty() || !itemStack.hasTag()) {
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+ return itemStack;
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+ }
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+
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+ final ItemStack copy = copyItemStack ? itemStack.copy() : itemStack;
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+ final CompoundTag tag = copy.getTag();
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+ if (copy.is(Items.BUNDLE) && tag.get("Items") instanceof ListTag oldItems && !oldItems.isEmpty()) {
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+ // Bundles change their texture based on their fullness.
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+ org.bukkit.inventory.meta.BundleMeta bundleMeta = (org.bukkit.inventory.meta.BundleMeta) copy.asBukkitMirror().getItemMeta();
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+ int sizeUsed = 0;
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+ for (org.bukkit.inventory.ItemStack item : bundleMeta.getItems()) {
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+ int scale = 64 / item.getMaxStackSize();
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+ sizeUsed += scale * item.getAmount();
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+ }
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+ // Now we add a single fake item that uses the same amount of slots as all other items.
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+ ListTag items = new ListTag();
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+ items.add(new ItemStack(Items.PAPER, sizeUsed).save(new CompoundTag()));
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+ tag.put("Items", items);
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+ }
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+ if (tag.get("BlockEntityTag") instanceof CompoundTag blockEntityTag) {
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+ blockEntityTag.remove("Items");
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+ }
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+ return copy;
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+ }
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+ // Paper end - prevent oversized data
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+
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private ItemStack getLastArmorItem(EquipmentSlot slot) {
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return (ItemStack) this.lastArmorItemStacks.get(slot.getIndex());
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}
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