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Readd root/admin user detection (#6593) 

* Readd root/admin user detection

* Use original test for Windows, use UID for unix and add co-author

* Move logging and remove unnecessary reader

* try with resources

* Use Windows security identifiers + reduce size of Unix check

* Remove extra newline at the bottom of the message

* Change wording

* Address comments

* Link to Maddy's article

* Use warning log level
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Noah van der Aa 2021-10-02 11:34:07 +02:00 committed by GitHub
parent f905057070
commit 45c4f90259
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patches/server/0814-Add-root-admin-user-detection.patch Normal file
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From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
From: egg82 <eggys82@gmail.com>
Date: Sat, 11 Sep 2021 22:55:14 +0200
Subject: [PATCH] Add root/admin user detection
This patch detects whether or not the server is currently executing as a privileged user and spits out a warning.
The warning serves as a sort-of PSA for newer server admins who don't understand the risks of running as root.
We've seen plenty of bad/malicious plugins hit markets, and there's been a few close-calls with exploits in the past.
Hopefully this helps mitigate some potential damage to servers, even if it is just a warning.
Co-authored-by: Noah van der Aa <ndvdaa@gmail.com>
diff --git a/src/main/java/io/papermc/paper/util/ServerEnvironment.java b/src/main/java/io/papermc/paper/util/ServerEnvironment.java
new file mode 100644
index 0000000000000000000000000000000000000000..0d8e415acb1e06532d9e1c2add576806b2aafdaa
--- /dev/null
+++ b/src/main/java/io/papermc/paper/util/ServerEnvironment.java
@@ -0,0 +1,24 @@
+package io.papermc.paper.util;
+
+import com.sun.security.auth.module.NTSystem;
+import com.sun.security.auth.module.UnixSystem;
+import org.apache.commons.lang.SystemUtils;
+
+import java.util.Set;
+
+public class ServerEnvironment {
+ private static final boolean RUNNING_AS_ROOT_OR_ADMIN;
+ private static final String WINDOWS_HIGH_INTEGRITY_LEVEL = "S-1-16-12288";
+
+ static {
+ if (SystemUtils.IS_OS_WINDOWS) {
+ RUNNING_AS_ROOT_OR_ADMIN = Set.of(new NTSystem().getGroupIDs()).contains(WINDOWS_HIGH_INTEGRITY_LEVEL);
+ } else {
+ RUNNING_AS_ROOT_OR_ADMIN = new UnixSystem().getUid() == 0L;
+ }
+ }
+
+ public static boolean userIsRootOrAdmin() {
+ return RUNNING_AS_ROOT_OR_ADMIN;
+ }
+}
diff --git a/src/main/java/net/minecraft/server/dedicated/DedicatedServer.java b/src/main/java/net/minecraft/server/dedicated/DedicatedServer.java
index 1bf19965d12514dee34545235bfbadc0b74ddc8b..49a85ad513993bfdc0759f26d38923c881af82e6 100644
--- a/src/main/java/net/minecraft/server/dedicated/DedicatedServer.java
+++ b/src/main/java/net/minecraft/server/dedicated/DedicatedServer.java
@@ -190,6 +190,16 @@ public class DedicatedServer extends MinecraftServer implements ServerInterface
DedicatedServer.LOGGER.warn("To start the server with more ram, launch it as \"java -Xmx1024M -Xms1024M -jar minecraft_server.jar\"");
}
+ // Paper start - detect running as root
+ if (io.papermc.paper.util.ServerEnvironment.userIsRootOrAdmin()) {
+ DedicatedServer.LOGGER.warn("****************************");
+ DedicatedServer.LOGGER.warn("YOU ARE RUNNING THIS SERVER AS AN ADMINISTRATIVE OR ROOT USER. THIS IS NOT ADVISED.");
+ DedicatedServer.LOGGER.warn("YOU ARE OPENING YOURSELF UP TO POTENTIAL RISKS WHEN DOING THIS.");
+ DedicatedServer.LOGGER.warn("FOR MORE INFORMATION, SEE https://madelinemiller.dev/blog/root-minecraft-server/");
+ DedicatedServer.LOGGER.warn("****************************");
+ }
+ // Paper end
+
DedicatedServer.LOGGER.info("Loading properties");
DedicatedServerProperties dedicatedserverproperties = this.settings.getProperties();