How to Obfuscate a fatJar with Klassmaster

Question

I have a fat jar which is generated by using gradle script. Post the gradle script when I run the following command :-

java -jar fileName.jar

it is running the main method and things are fine. Nevertheless when I try to obfuscate this jar, the resulting jar is complaining that :-

Error: Invalid or corrupt jarfile ObfusactedTest.jar

My code is as follows:-

build.gradle:-

    buildscript {
    repositories {
        mavenLocal()
        mavenCentral()
    }

    dependencies {
        classpath files("E:\\softs\\ZKM\\ZKMEval\\ZKM.jar") //ZKM_JAR_PATH must be set to point to your ZKM.jar
        classpath 'com.zelix.gradle:plugin:1.0.0'
    }
}

apply plugin: 'java'
apply plugin: 'maven'
apply plugin: 'com.zelix.gradle.plugin'

group = 'com.github.jitpack'

sourceCompatibility = 1.8 // java 8
targetCompatibility = 1.8

repositories {
    mavenLocal()
    mavenCentral()
}

dependencies {
    compile group: 'org.apache.commons', name: 'commons-lang3', version: '3.11'
    compile group: 'org.apache.commons', name: 'commons-collections4', version: '4.4'
}

jar {
    manifest {
        attributes "Main-Class": "com.github.jitpack.Hello"
    }
    zip64 = true
    from {
        configurations.compile.collect { it.isDirectory() ? it : zipTree(it) }
    }
}


zkmSetting {
    scriptName = "Obfuscate.txt" //Must be set to point to the ZKM Script to execute.
}

Obfuscate.txt:-

print "Obfuscating fatJar.....";

classpath
          "C:\Program Files\Java\jdk-10.0.2\lib\jrt-fs.jar"
          ".\obfuscateFatJar.jar";

open ".\obfuscateFatJar.jar" {"*.class"};

exclude org.apache.commons.*.*;
exclude com.github.jitpack.Hello.*;

obfuscate keepInnerClassInfo=false
           keepGenericsInfo=true
           exceptionObfuscation=heavy
           encryptStringLiterals=flowObfuscate;

saveAll archiveCompression=asIs
        deleteEmptyDirectories=true
        deleteXMLComments=false
        "ObfusactedTest.jar";

By the way Hello.java has got the main method.

Answer 1

Your ZKM Script "open" statement specifies the {"*.class"} file filter. So you are filtering out ALL non-class files including your MANIFEST.MF. See https://www.zelix.com/klassmaster/docs/openStatement.html#filter.

A missing MANIFEST.MF will give you a "Invalid or corrupt jarfile" error. Note that your Zelix KlassMaster log file will contain messages like the following.

MESSAGE: Filtering out path 'obfuscateFatJar.jar!META-INF/MANIFEST.MF' because it does not match specified filter '{".class"}>' (D)*

You can work around this by not using a file filter (the safest option in this case) or by broadening your file filter to include other file types. E.g. {".class" || ".MF"}

Answer 2

Update the filter in the class path. The code looks like this now. Works like a charm.

execute "del ObfusactedTest.jar";

classpath
          "C:\Program Files\Java\jdk-10.0.2\lib\jrt-fs.jar"
          ".\obfuscateFatJar.jar";

open ".\obfuscateFatJar.jar" {"*.class" || "*.MF"};

exclude org.apache.commons.*.*;

obfuscate keepInnerClassInfo=false
           keepGenericsInfo=true
           exceptionObfuscation=heavy
           encryptStringLiterals=flowObfuscate;

saveAll archiveCompression=asIs
        deleteEmptyDirectories=true
        deleteXMLComments=false
        "ObfusactedTest.jar";