Threadtear：一款多功能 Java 代码反混淆工具套件，小米 java 社招面试
public class MyExecution extends Execution {
public MyExecution() {
super(ExecutionCategory.CLEANING /* category /, "My execution" / name */,
"Executes something" /* description, can use html */);
}
/**
This method is invoked when the user clicks on the Run button
@return true if success, false if failure
*/
@Override
public boolean execute(Map<String, Clazz> classes, boolean verbose) {
classes.values().stream().map(c -> c.node).forEach(c -> {
//transform the classes here using the tree-API of ASM
});
return false;
}
}
在运行时加载 ClassNodes 类，可以直接使用?
me.nov.threadtear.asm.vm.VM 类并实现?
me.nov.threadtear.asm.vm.IVMReferenceHandler 方法：
public class MyExecution extends Execution implements IVMReferenceHandler {
public MyExecution() {
super(ExecutionCategory.GENERIC, "My execution", "Loads ClassNodes at runtime");
}
@Override
public boolean execute(Map<String, Clazz> classes, boolean verbose) {
classes.values().stream().map(c -> c.node).forEach(c -> {
VM vm = VM.constructVM(this);
//transform bytecode to java.lang.Class
Class<?> loadedClass = vm.loadClass(c.name.replace('/', '.'), true);
//do stuff with your class here
loadedClass.getMethods[0].invoke(...);
return true;
});
}
/**
Will get invoked by VM, when VM.loadClass is called
*/
@Override
public ClassNode tryClassLoad(String name) {
//try to find the class to be loaded in open jar archive
return classes.containsKey(name) ? classes.get(name).node : null;
}
}
通过使用?
me.nov.threadtear.analysis.stack.ConstantTracker 方法，你可以分析目标代码中的方法并追踪非变量栈值：
public class MyExecution extends Execution implements IConstantReferenceHandler {
public MyExecution() {
super(ExecutionCategory.GENERIC, "My execution", "Performs stack analysis and replaces code.");
}
@Override
public boolean execute(Map<String, Clazz> classes, boolean verbose) {
classes.values().stream().map(c -> c.node).forEach(this::analyzeAndRewrite);
return true;
}
public void analyzeAndRewrite(ClassNode cn) {
cn.methods.forEach(m -> {
// this analyzer keeps known stack values, e.g. can be useful for jump prediction
Analyzer<ConstantValue> a = new Analyzer<ConstantValue>(new ConstantTracker(this, Access.isStatic(m.access), m.maxLocals, m.desc, new Object[0]));
try {
a.analyze(cn.name, m);
} catch (AnalyzerException e) {
logger.severe("Failed stack analysis in " + cn.name + "." + m.name + ":" + e.getMessage());
return;
}
Frame<ConstantValue>[] frames = a.getFrames();
InsnList rewrittenCode = new InsnList();
Map<LabelNode, LabelNode> labels = Instructions.cloneLabels(m.instructions);
// rewrite method instructions
for (int i = 0; i < m.instructions.size(); i++) {
AbstractInsnNode ain = m.instructions.get(i);
Frame<ConstantValue> frame = frames[i];
// replace / modify instructions, etc...
if (frame.getStackSize() > 0) {
ConstantValue top = frame.getStack(frame.getStackSize() - 1);
if (top.isKnown() && top.isInteger()) {
int knownTopStackValue = top.getInteger();
// use the known stack to remove jumps, simplify code, etc...
// if(...) { rewrittenCode.add(...); }
continue;
}
}
rewrittenCode.add(ain.clone(labels));
}
// update instructions and fix try catch blocks, local variables, etc...
Instructions.updateInstructions(m, labels, rewrittenCode);
});
}
/**
Use this method to predict stack values if fields are loaded
*/
@Override
public Object getFieldValueOrNull(BasicValue v, String owner, String name, String desc)
{
return null;
}
/**
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