Paper: Does not block Illegal Packet

[LemonCaramel]

I have asked the Discord channel several times and I am writing an issue because there is no answer.

I am not good at English and used a translator.

I'm not sure on a server that can only access 1.15.2, but it's a very serious problem for a 1.12.2-1.15.2 server.

When using "LogSpammer Hack"(1.12.2 hack) in paper 1.15.2, the player join, server shutdown(/stop command) and other(...) do not work with the error below.

If I have to turn off the server, I have to click the console window close button to force it to shut down.

I think this is a very serious problem. I hope it will be resolved quickly.

Steps/models to reproduce:

Youtube Video

Plugin list:

ProtocolSupport, ProtocolSupportLegacyChest

Paper build number: 1.15.2 (227)

Error log:

[23:48:42 FATAL]: Error executing task on Server
java.lang.ArrayIndexOutOfBoundsException: 209770667
at java.util.Arrays$ArrayList.get(Arrays.java:3841) ~[?:1.8.0_241]
at net.minecraft.server.v1_15_R1.NonNullList.get(SourceFile:46) ~[patched_1.15.2.jar:git-Paper-227]
at net.minecraft.server.v1_15_R1.PlayerInventory.c(PlayerInventory.java:135) ~[patched_1.15.2.jar:git-Paper-227] at net.minecraft.server.v1_15_R1.PlayerConnection.a(PlayerConnection.java:686) ~[patched_1.15.2.jar:git-Paper-227]
at net.minecraft.server.v1_15_R1.PacketPlayInPickItem.a(SourceFile:30) ~[patched_1.15.2.jar:git-Paper-227]
at net.minecraft.server.v1_15_R1.PacketPlayInPickItem.a(SourceFile:8) ~[patched_1.15.2.jar:git-Paper-227]
at net.minecraft.server.v1_15_R1.PlayerConnectionUtils.lambda$ensureMainThread$0(PlayerConnectionUtils.java:23) ~[patched_1.15.2.jar:git-Paper-227]
at net.minecraft.server.v1_15_R1.TickTask.run(SourceFile:18) ~[patched_1.15.2.jar:git-Paper-227]
at net.minecraft.server.v1_15_R1.IAsyncTaskHandler.executeTask(IAsyncTaskHandler.java:136) ~[patched_1.15.2.jar:git-Paper-227]
at net.minecraft.server.v1_15_R1.IAsyncTaskHandlerReentrant.executeTask(SourceFile:23) ~[patched_1.15.2.jar:git-Paper-227]
at net.minecraft.server.v1_15_R1.IAsyncTaskHandler.executeNext(IAsyncTaskHandler.java:109) ~[patched_1.15.2.jar:git-Paper-227]
at net.minecraft.server.v1_15_R1.MinecraftServer.ba(MinecraftServer.java:1081) ~[patched_1.15.2.jar:git-Paper-227]
at net.minecraft.server.v1_15_R1.MinecraftServer.executeNext(MinecraftServer.java:1074) ~[patched_1.15.2.jar:git-Paper-227]
at net.minecraft.server.v1_15_R1.IAsyncTaskHandler.awaitTasks(IAsyncTaskHandler.java:119) ~[patched_1.15.2.jar:git-Paper-227]
at net.minecraft.server.v1_15_R1.MinecraftServer.sleepForTick(MinecraftServer.java:1035) ~[patched_1.15.2.jar:git-Paper-227]
at net.minecraft.server.v1_15_R1.MinecraftServer.run(MinecraftServer.java:950) ~[patched_1.15.2.jar:git-Paper-227]
at java.lang.Thread.run(Thread.java:748) [?:1.8.0_241]

[Proximyst]

Try to reproduce without a plugin doing borderline criminal acts on the packets.

[aikar]

This is now fixed in latest build.

The wording had me going back and forth on was this for 1.12 or not...

[Rekryt]

[16:57:58] [Server thread/WARN]: BanaMan tried to set an invalid carried item
mouse3 click on empty slot (with select block that have in inventory) server kick player

[Subilan]

[16:57:58] [Server thread/WARN]: BanaMan tried to set an invalid carried item
[16:57:58] [Server thread/INFO]: BanaMan lost connection: Invalid hotbar selection (Hacking?)
[16:57:58] [Server thread/WARN]: handleDisconnection() called twice

mouse3 click on empty slot (with select block that have in inventory) server kick player

Same here too.

[HexedHero]

Same issue here with normal building when getting new item stacks from inventory into hotbar

[aikar]

This is fixed in latest build