From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001 From: Spottedleaf 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 ed3af916dfa875dd0a5f1e730d20d11efd6419c6..cd4e76fe5b79c7d9e615b4886a568c74db757436 100644 --- a/src/main/java/net/minecraft/server/network/ServerLoginPacketListenerImpl.java +++ b/src/main/java/net/minecraft/server/network/ServerLoginPacketListenerImpl.java @@ -60,6 +60,7 @@ public class ServerLoginPacketListenerImpl implements ServerLoginPacketListener, private final String serverId; @Nullable private ServerPlayer delayedAcceptPlayer; + public boolean iKnowThisMayNotBeTheBestIdeaButPleaseDisableUsernameValidation = false; // Paper - username validation overriding public ServerLoginPacketListenerImpl(MinecraftServer server, Connection connection) { this.state = ServerLoginPacketListenerImpl.State.HELLO; @@ -212,10 +213,38 @@ public class ServerLoginPacketListenerImpl implements ServerLoginPacketListener, // Paper end } + // Paper start - validate usernames + public static boolean validateUsername(String in) { + if (in == null || in.isEmpty() || in.length() > 16) { + return false; + } + + for (int i = 0, len = in.length(); i < len; ++i) { + char c = in.charAt(i); + + if ((c >= 'a' && c <= 'z') || (c >= 'A' && c <= 'Z') || (c >= '0' && c <= '9') || (c == '_' || c == '.')) { + continue; + } + + return false; + } + + return true; + } + // Paper end - validate usernames + @Override public void handleHello(ServerboundHelloPacket packet) { Validate.validState(this.state == ServerLoginPacketListenerImpl.State.HELLO, "Unexpected hello packet", new Object[0]); Validate.validState(ServerLoginPacketListenerImpl.isValidUsername(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) { + if (!this.iKnowThisMayNotBeTheBestIdeaButPleaseDisableUsernameValidation && !validateUsername(packet.name())) { + ServerLoginPacketListenerImpl.this.disconnect("Failed to verify username!"); + return; + } + } + // Paper end - validate usernames GameProfile gameprofile = this.server.getSingleplayerProfile(); if (gameprofile != null && packet.name().equalsIgnoreCase(gameprofile.getName())) { diff --git a/src/main/java/net/minecraft/server/players/PlayerList.java b/src/main/java/net/minecraft/server/players/PlayerList.java index 432c9e4e2b16b18f795e854f4cbe30b7e14a8947..42e7b41526f7cf31f33a58f18e851cd435472921 100644 --- a/src/main/java/net/minecraft/server/players/PlayerList.java +++ b/src/main/java/net/minecraft/server/players/PlayerList.java @@ -673,7 +673,7 @@ 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); } }