Prevent loading JndiLookup to patch CVE-2021-45046

Author: acrylic-style

pom.xml

@@ -6,7 +6,7 @@
 
     <groupId>net.azisaba</groupId>
     <artifactId>Log4j2Fix</artifactId>
-    <version>1.0.3</version>
+    <version>1.0.4</version>
 
     <properties>
         <maven.compiler.source>8</maven.compiler.source>

src/main/java/net/azisaba/log4j2Fix/Log4j2Fix.java

@@ -17,6 +17,7 @@
 import java.util.zip.ZipFile;
 
 public class Log4j2Fix {
+    private static boolean registered = false;
     private static String arg;
     private static Instrumentation inst;
 
@@ -96,13 +97,14 @@ public static void premain(String args, Instrumentation instrumentation) throws
     }
 
     public static void transformClasses() throws IOException {
-        transformClass("org.apache.logging.log4j.core.appender.mom.JmsAppender", false);
-        transformClass("org.apache.logging.log4j.core.appender.mom.JmsAppender$1", false);
-        transformClass("org.apache.logging.log4j.core.appender.mom.JmsAppender$Builder", false);
-        transformClass("org.apache.logging.log4j.core.net.JndiManager", false);
-        transformClass("org.apache.logging.log4j.core.net.JndiManager$1", false);
-        transformClass("org.apache.logging.log4j.core.net.JndiManager$JndiManagerFactory", false);
-        transformClass("org.apache.logging.log4j.core.util.NetUtils", false);
+        if (registered) return;
+        registered = true;
+        NativeUtil.registerClassLoadHook((classLoader, s, aClass, protectionDomain, bytes) -> {
+            if ("org/apache/logging/log4j/core/lookup/JndiLookup".equals(s) || s.startsWith("org/apache/logging/log4j/core/lookup/JndiLookup$")) {
+                sneakyThrow(new ClassNotFoundException());
+            }
+            return null;
+        });
         if (Boolean.getBoolean("log4j2Fix.loadReflectionUtil")) {
             transformClass("org.apache.logging.log4j.util.ReflectionUtil", true);
             transformClass("org.apache.logging.log4j.util.ReflectionUtil$PrivateSecurityManager", true);
@@ -144,4 +146,9 @@ public static byte[] readAllBytes(InputStream in) throws IOException {
         }
         return baos.toByteArray();
     }
+
+    @SuppressWarnings("unchecked")
+    public static <X extends Throwable> void sneakyThrow(Throwable throwable) throws X {
+        throw (X) throwable;
+    }
 }