PaperMC/patches/server/0867-Fix-concurrenct-access-to-lookups-field-in-RegistryO.patch
Owen 89d51d5f29
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.
2024-03-03 17:05:34 -05:00

33 lines
2.1 KiB
Diff

From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
From: Spottedleaf <Spottedleaf@users.noreply.github.com>
Date: Mon, 15 May 2023 00:20:59 -0700
Subject: [PATCH] Fix concurrenct access to lookups field in RegistryOps
The concurrent access occurs on the Netty IO threads when
serializing packets. Thus, it seems it was an oversight of
the implementator of this function as there are typically
more than one Netty IO thread.
Fixes https://github.com/PaperMC/Folia/issues/11
diff --git a/src/main/java/net/minecraft/resources/RegistryOps.java b/src/main/java/net/minecraft/resources/RegistryOps.java
index 7709eeac907c4895a264cec0a3d453aa8b194c18..c7cfc3ca58f9439142fe5828117f6d576d7df10e 100644
--- a/src/main/java/net/minecraft/resources/RegistryOps.java
+++ b/src/main/java/net/minecraft/resources/RegistryOps.java
@@ -19,11 +19,14 @@ public class RegistryOps<T> extends DelegatingOps<T> {
private static RegistryOps.RegistryInfoLookup memoizeLookup(final RegistryOps.RegistryInfoLookup registryInfoGetter) {
return new RegistryOps.RegistryInfoLookup() {
- private final Map<ResourceKey<? extends Registry<?>>, Optional<? extends RegistryOps.RegistryInfo<?>>> lookups = new HashMap<>();
+ // The concurrent access occurs on the Netty IO threads when serializing packets.
+ // Thus, it seems it was an oversight of the implementator of this function as there
+ // are typically more than one Netty IO thread.
+ private final Map<ResourceKey<? extends Registry<?>>, Optional<? extends RegistryOps.RegistryInfo<?>>> lookups = new java.util.concurrent.ConcurrentHashMap<>(); // Paper - fix concurrent access to lookups field
@Override
public <T> Optional<RegistryOps.RegistryInfo<T>> lookup(ResourceKey<? extends Registry<? extends T>> registryRef) {
- return this.lookups.computeIfAbsent(registryRef, registryInfoGetter::lookup);
+ return (Optional<RegistryOps.RegistryInfo<T>>)this.lookups.computeIfAbsent(registryRef, registryInfoGetter::lookup); // Paper - fix concurrent access to lookups field
}
};
}