我正在尝试做一个简单的 Java 字节码混淆器，它通过用GOTO简单的条件跳转替换指令来工作，比如if 10 != 15 GOTO else throw IllegalStateException. 我目前的代码是：
final AbstractInsnNode[] insns = method.instructions.toArray().clone();
for (final AbstractInsnNode insn : insns) {
final int op = insn.getOpcode();
if ((op == GOTO) || (op == IFLE) || (op == IFGE)) {
LabelNode l0 = new LabelNode();
LabelNode l1 = new LabelNode();
LabelNode l2 = new LabelNode();
int locals = (method.localVariables == null) ? 0 : method.localVariables.size();
int params = (method.parameters == null) ? 0 : method.parameters.size();
int v0index = locals + params;
int v1index = v0index + 1;
int exindex = v1index + 1;
// Init fake conditional fields
method.instructions.insertBefore(insn, new LdcInsnNode(10F));
method.instructions.insertBefore(insn, new VarInsnNode(FSTORE, v0index));
method.instructions.insertBefore(insn, new LdcInsnNode(45F));
method.instructions.insertBefore(insn, new VarInsnNode(FSTORE, v1index));
// Crossing jumps
method.instructions.insertBefore(insn, l1);
method.instructions.insert(insn, l0);
method.instructions.insert(l0, l2);
LabelNode l3 = new LabelNode();
LabelNode l4 = new LabelNode();
method.instructions.insert(l2, l3);
method.instructions.insert(l3, l4);
// If 'v0!=v1', jump to l0, otherwise goto l3
method.instructions.insertBefore(l1, new VarInsnNode(FLOAD, v0index));
method.instructions.insertBefore(l1, new VarInsnNode(FLOAD, v1index));
method.instructions.insertBefore(l1, new InsnNode(FCMPG));
method.instructions.insertBefore(l1, new JumpInsnNode(IFNE, l0));
method.instructions.insertBefore(l1, new JumpInsnNode(GOTO, l3));
// Jump to l3 results in throwing an exception
// Create and throw the exception
method.instructions.insertBefore(l4, new TypeInsnNode(NEW, "java/lang/IllegalStateException"));
method.instructions.insertBefore(l4, new InsnNode(DUP));
method.instructions.insertBefore(l4, new MethodInsnNode(INVOKESPECIAL, "java/lang/IllegalStateException", "<init>", "()V", false));
method.instructions.insertBefore(l4, new InsnNode(ATHROW));
method.instructions.insertBefore(l0, new JumpInsnNode(GOTO, l2));
method.instructions.insertBefore(l2, new JumpInsnNode(GOTO, l1));
// Exception handler
LabelNode start = new LabelNode();
LabelNode handler = new LabelNode();
LabelNode end = new LabelNode();
method.instructions.insertBefore(l0, start);
method.instructions.insert(l2, end);
method.instructions.insert(end, handler);
// Just throw the exception again
LabelNode l5 = new LabelNode();
method.instructions.insert(handler, l5);
method.instructions.insertBefore(l5, new TypeInsnNode(NEW, "java/lang/IllegalStateException"));
method.instructions.insertBefore(l5, new InsnNode(DUP));
method.instructions.insertBefore(l5, new MethodInsnNode(INVOKESPECIAL, "java/lang/IllegalStateException", "<init>", "()V", false));
method.instructions.insertBefore(l5, new InsnNode(ATHROW));
// Try/catch
TryCatchBlockNode tryBlock = new TryCatchBlockNode(start, end, handler, "java/lang/IllegalStateException");
method.tryCatchBlocks.add(tryBlock);
// Init local variables
method.visitLocalVariable("_v0_" + Rand.alphaNumeric(5), "F", null, l0.getLabel(), l2.getLabel(), v0index);
method.visitLocalVariable("_v1_" + Rand.alphaNumeric(5), "F", null, l0.getLabel(), l2.getLabel(), v1index);
method.visitLocalVariable("_ex_" + Rand.alphaNumeric(5), "Ljava/lang/IllegalArgumentException;", null, start.getLabel(), handler.getLabel(), exindex);
}
}
methodtype 的混淆方法的参数在哪里MethodNode，并且该类实现了 interface Opcodes。
这很好用，但不适用于所有方法（我对字节码很陌生，所以不知道具体情况）。例如，它适用于以下main方法：
原始 Java 代码（在 Procyon 中反编译）： https ://p.reflex.rip/DLMT.cs
原始字节码： https ://p.reflex.rip/ywJt.go
混淆的 Java 代码（在 Procyon 中反编译）： https ://p.reflex.rip/Er9V.cs
混淆字节码： https ://p.reflex.rip/JBAb.go
但是，它破坏了其他divMinByMax方法之一：
原始 Java 代码（在 Procyon 中反编译）： https ://p.reflex.rip/AW9W.java
原始字节码： https ://p.reflex.rip/GX2k.cpp
混淆的 Java 代码（在 Procyon 中反编译，失败）： https ://p.reflex.rip/Eqju.java
混淆字节码： https ://p.reflex.rip/isiX.cpp
当我尝试使用以下命令运行混淆的 JAR 时，此方法会导致VerifyErrorjava -jar：
Error: A JNI error has occurred, please check your installation and try again
Exception in thread "main" java.lang.VerifyError: Inconsistent stackmap frames at branch target 27
Exception Details:
Location:
test/one/HelloRandom.divMinByMax(DD)D @21: goto
Reason:
Current frame's stack size doesn't match stackmap.
Current Frame:
bci: @21
flags: { }
locals: { double, double_2nd, float, float }
stack: { }
Stackmap Frame:
bci: @27
flags: { }
locals: { double, double_2nd, float, float }
stack: { 'java/lang/IllegalStateException' }
Bytecode:
0x0000000: 2826 9712 7145 1272 4624 2596 9a00 0ca7
0x0000010: 0014 9e00 48a7 0006 a7ff fabb 0016 59b7
0x0000020: 0073 bfbb 0016 59b7 0073 bf00 0000 0000
0x0000030: 00bf 0000 00bf 0000 0000 0000 00bf 0000
0x0000040: bf00 00bf 0000 bf00 00bf 0000 0000 0000
0x0000050: 00bf 0000 0000 0000 00bf 2826 6faf
Exception Handler Table:
bci [24, 27] => handler: 27
Stackmap Table:
full_frame(@18,{Double,Float,Float},{Integer})
same_locals_1_stack_item_frame(@24,Integer)
same_locals_1_stack_item_frame(@27,Object[#22])
same_locals_1_stack_item_frame(@35,Integer)
full_frame(@43,{},{Object[#159]})
same_locals_1_stack_item_frame(@50,Object[#159])
same_locals_1_stack_item_frame(@54,Object[#159])
same_locals_1_stack_item_frame(@62,Object[#159])
same_locals_1_stack_item_frame(@65,Object[#159])
same_locals_1_stack_item_frame(@68,Object[#159])
same_locals_1_stack_item_frame(@71,Object[#159])
same_locals_1_stack_item_frame(@74,Object[#159])
same_locals_1_stack_item_frame(@82,Object[#159])
append_frame(@90,Double,Float,Float)
same_locals_1_stack_item_frame(@93,Double)
我做了很多研究，唯一找到的就是原因：据我所知，问题在于堆栈打开@21（GOTO跳转到标签执行throw new IllegalStateException）：
stack: { }
@27（为空）与跳转目标标签上的 ,处的堆栈不匹配：
stack: { 'java/lang/IllegalStateException' }
（其中包含它应该“抛出”的异常）。
所以基本上，据我所知，错误发生在我尝试执行GOTO <n>跳转时，<n>其中“抛出”一个IllegalStateException.
我该如何解决这个问题？也许有一种方法可以在跳转之前使堆栈@21包含java/lang/IllegalStateException在跳转之前（以便这两个堆栈，一个在跳转之前和一个在跳转之后，匹配）？或者我可以用它做些什么？