PaperMC/patches/server/0644-Validate-usernames.patch
Bjarne Koll c5a10665b8
Remove wall-time / unused skip tick protection (#11412)
Spigot still maintains some partial implementation of "tick skipping", a
practice in which the MinecraftServer.currentTick field is updated not
by an increment of one per actual tick, but instead set to
System.currentTimeMillis() / 50. This behaviour means that the tracked
tick may "skip" a tick value in case a previous tick took more than the
expected 50ms.

To compensate for this in important paths, spigot/craftbukkit
implements "wall-time". Instead of incrementing/decrementing ticks on
block entities/entities by one for each call to their tick() method,
they instead increment/decrement important values, like
an ItemEntity's age or pickupDelay, by the difference of
`currentTick - lastTick`, where `lastTick` is the value of
`currentTick` during the last tick() call.

These "fixes" however do not play nicely with minecraft's simulation
distance as entities/block entities implementing the above behaviour
would "catch up" their values when moving from a non-ticking chunk to a
ticking one as their `lastTick` value remains stuck on the last tick in
a ticking chunk and hence lead to a large "catch up" once ticked again.

Paper completely removes the "tick skipping" behaviour (See patch
"Further-improve-server-tick-loop"), making the above precautions
completely unnecessary, which also rids paper of the previous described
incompatibility with non-ticking chunks.
2024-09-19 16:36:07 +02:00

76 lines
4.3 KiB
Diff

From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
From: Spottedleaf <Spottedleaf@users.noreply.github.com>
Date: Sat, 1 Jan 2022 05:19:37 -0800
Subject: [PATCH] Validate usernames
diff --git a/src/main/java/net/minecraft/server/network/ServerLoginPacketListenerImpl.java b/src/main/java/net/minecraft/server/network/ServerLoginPacketListenerImpl.java
index e0a10f1d8bf2c0df66e62bdf2a174ce6a66bbd6d..9c343b579d9735dc59c8c74fde030d981a673c4f 100644
--- a/src/main/java/net/minecraft/server/network/ServerLoginPacketListenerImpl.java
+++ b/src/main/java/net/minecraft/server/network/ServerLoginPacketListenerImpl.java
@@ -90,6 +90,7 @@ public class ServerLoginPacketListenerImpl implements ServerLoginPacketListener,
private final String serverId;
private final boolean transferred;
private ServerPlayer player; // CraftBukkit
+ public boolean iKnowThisMayNotBeTheBestIdeaButPleaseDisableUsernameValidation = false; // Paper - username validation overriding
public ServerLoginPacketListenerImpl(MinecraftServer server, Connection connection, boolean transferred) {
this.state = ServerLoginPacketListenerImpl.State.HELLO;
@@ -171,7 +172,13 @@ public class ServerLoginPacketListenerImpl implements ServerLoginPacketListener,
@Override
public void handleHello(ServerboundHelloPacket packet) {
Validate.validState(this.state == ServerLoginPacketListenerImpl.State.HELLO, "Unexpected hello packet", new Object[0]);
- Validate.validState(StringUtil.isValidPlayerName(packet.name()), "Invalid characters in username", new Object[0]);
+ // Paper start - Validate usernames
+ if (io.papermc.paper.configuration.GlobalConfiguration.get().proxies.isProxyOnlineMode()
+ && io.papermc.paper.configuration.GlobalConfiguration.get().unsupportedSettings.performUsernameValidation
+ && !this.iKnowThisMayNotBeTheBestIdeaButPleaseDisableUsernameValidation) {
+ Validate.validState(StringUtil.isReasonablePlayerName(packet.name()), "Invalid characters in username", new Object[0]);
+ }
+ // Paper end - Validate usernames
this.requestedUsername = packet.name();
GameProfile gameprofile = this.server.getSingleplayerProfile();
diff --git a/src/main/java/net/minecraft/server/players/PlayerList.java b/src/main/java/net/minecraft/server/players/PlayerList.java
index c7dc335d6da208c224d94256eab11b2c3c63745f..cff45afb90b232a236683bd569d50aab6b701149 100644
--- a/src/main/java/net/minecraft/server/players/PlayerList.java
+++ b/src/main/java/net/minecraft/server/players/PlayerList.java
@@ -670,7 +670,7 @@ public abstract class PlayerList {
for (int i = 0; i < this.players.size(); ++i) {
entityplayer = (ServerPlayer) this.players.get(i);
- if (entityplayer.getUUID().equals(uuid)) {
+ if (entityplayer.getUUID().equals(uuid) || (io.papermc.paper.configuration.GlobalConfiguration.get().proxies.isProxyOnlineMode() && entityplayer.getGameProfile().getName().equalsIgnoreCase(gameprofile.getName()))) { // Paper - validate usernames
list.add(entityplayer);
}
}
diff --git a/src/main/java/net/minecraft/util/StringUtil.java b/src/main/java/net/minecraft/util/StringUtil.java
index d3fc549a08993376c76c4ebebb788fea3f4ddf69..0bd191acb9596d3aa21c337230d26f09d26f6888 100644
--- a/src/main/java/net/minecraft/util/StringUtil.java
+++ b/src/main/java/net/minecraft/util/StringUtil.java
@@ -67,6 +67,25 @@ public class StringUtil {
return name.length() <= 16 && name.chars().filter(c -> c <= 32 || c >= 127).findAny().isEmpty();
}
+ // Paper start - Username validation
+ public static boolean isReasonablePlayerName(final String name) {
+ if (name.isEmpty() || name.length() > 16) {
+ return false;
+ }
+
+ for (int i = 0, len = name.length(); i < len; ++i) {
+ final char c = name.charAt(i);
+ if ((c >= 'a' && c <= 'z') || (c >= 'A' && c <= 'Z') || (c >= '0' && c <= '9') || (c == '_' || c == '.')) {
+ continue;
+ }
+
+ return false;
+ }
+
+ return true;
+ }
+ // Paper end - Username validation
+
public static String filterText(String string) {
return filterText(string, false);
}