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Java Bytecode Manipulation Added
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‎bytecode-manipulation/ByteCodeEditor.java

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/*******************************************************************************
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Copyright (c) 2017 Venish Joe Clarence (http://venishjoe.net)
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Permission is hereby granted, free of charge, to any person obtaining a copy
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of this software and associated documentation files (the "Software"), to deal
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in the Software without restriction, including without limitation the rights
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to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
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copies of the Software, and to permit persons to whom the Software is
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furnished to do so, subject to the following conditions:
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The above copyright notice and this permission notice shall be included in all
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copies or substantial portions of the Software.
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THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
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AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
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LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
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OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
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SOFTWARE.
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******************************************************************************/
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import javassist.ClassPool;
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import javassist.CtClass;
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import javassist.CtMethod;
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import javassist.CtNewMethod;
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import javassist.bytecode.CodeAttribute;
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import javassist.bytecode.CodeIterator;
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import javassist.bytecode.InstructionPrinter;
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import javassist.bytecode.Mnemonic;
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import java.io.FileInputStream;
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import java.io.PrintStream;
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public class ByteCodeEditor {
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public static void main (String args[]) throws Exception {
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ByteCodeEditor _byteCodeEditor = new ByteCodeEditor();
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//Load test class
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ClassPool _classPool = ClassPool.getDefault();
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CtClass _ctClass = _classPool.makeClass(new FileInputStream("ByteCodeEditorTest.class"));
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//Call Manipulate method to change OPCODE
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_byteCodeEditor.manipulateComparision(_ctClass);
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//Other basic static analyis and manipulation functions
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_byteCodeEditor.addNewMethod(_ctClass);
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_byteCodeEditor.insertCodeInMethod(_ctClass);
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_byteCodeEditor.printMethodCode(_ctClass);
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_byteCodeEditor.printByteCode(_ctClass);
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}
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public static void manipulateComparision (CtClass _ctClass) throws Exception {
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for(CtMethod _ctMethods:_ctClass.getDeclaredMethods()){
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System.out.println("Starting Byte Code Editor. Inside Method: " + _ctMethods.getName());
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CodeAttribute _codeAttribute = _ctMethods.getMethodInfo().getCodeAttribute();
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CodeIterator _codeIterator = _codeAttribute.iterator();
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while (_codeIterator.hasNext()) {
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int _indexOfCode = _codeIterator.next();
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int _valueOfIndex8Bit = _codeIterator.byteAt(_indexOfCode);
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if(_valueOfIndex8Bit==153 && _indexOfCode==6) {
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System.out.println("Trying to update " + _valueOfIndex8Bit + " on index " + _indexOfCode);
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_codeIterator.writeByte(154, _indexOfCode);
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}
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}
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}
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_ctClass.writeFile();
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System.out.println("Update Successful!\n");
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}
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public static void addNewMethod (CtClass _ctClass) throws Exception {
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_ctClass.defrost();
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System.out.println("Starting to add new method");
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CtMethod _ctMethod = CtNewMethod.make("public int newMethodFromJA() { return 1; }", _ctClass);
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_ctClass.writeFile();
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System.out.println("Addition Successful!\n");
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}
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public static void printMethodCode (CtClass _ctClass) throws Exception {
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PrintStream ps = new PrintStream(System.out);
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InstructionPrinter instructionPrinter = new InstructionPrinter(ps);
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for(CtMethod method:_ctClass.getDeclaredMethods()){
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System.out.println("Method: " + method.getName());
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instructionPrinter.print(method);
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}
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}
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public static void printByteCode (CtClass _ctClass) throws Exception {
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for(CtMethod _ctMethods:_ctClass.getDeclaredMethods()){
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_ctClass.defrost();
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System.out.println("Method: " +_ctMethods.getName());
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CodeAttribute _codeAttribute = _ctMethods.getMethodInfo().getCodeAttribute();
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CodeIterator _codeIterator = _codeAttribute.iterator();
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while (_codeIterator.hasNext()) {
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int _indexOfInstruction = _codeIterator.next();
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int _indexValue8Bit = _codeIterator.byteAt(_indexOfInstruction);
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System.out.println(Mnemonic.OPCODE[_indexValue8Bit]);
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}
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}
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}
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public static void insertCodeInMethod (CtClass _ctClass) throws Exception {
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System.out.println("Starting to insert new code");
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for(CtMethod method:_ctClass.getDeclaredMethods()){
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_ctClass.defrost();
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method.insertBefore("System.out.println(\"Before every method call....\");");
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_ctClass.writeFile();
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}
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System.out.println("Addition Successful!\n");
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}
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}

‎bytecode-manipulation/ByteCodeEditorTest.java

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/*******************************************************************************
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Copyright (c) 2017 Venish Joe Clarence (http://venishjoe.net)
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Permission is hereby granted, free of charge, to any person obtaining a copy
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of this software and associated documentation files (the "Software"), to deal
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in the Software without restriction, including without limitation the rights
7+
to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
8+
copies of the Software, and to permit persons to whom the Software is
9+
furnished to do so, subject to the following conditions:
10+
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The above copyright notice and this permission notice shall be included in all
12+
copies or substantial portions of the Software.
13+
14+
THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
15+
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
16+
FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
17+
AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
18+
LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
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OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
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SOFTWARE.
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******************************************************************************/
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public class ByteCodeEditorTest {
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public static void main (String args[]) {
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System.out.println(new ByteCodeEditorTest().checkStatus(args[0]));
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}
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//Simple method to check if input matches MAGIC
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public String checkStatus(String _inputString){
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if (_inputString.equals("MAGIC"))
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return "Right!";
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return "Wrong";
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}
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}

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