Java ASM-分支目标处的堆栈映射帧不一致
我正在尝试做一个简单的Java字节码模糊器,其工作原理是用简单的条件跳转替换Java ASM-分支目标处的堆栈映射帧不一致,java,bytecode,java-bytecode-asm,bytecode-manipulation,jvm-bytecode,Java,Bytecode,Java Bytecode Asm,Bytecode Manipulation,Jvm Bytecode,我正在尝试做一个简单的Java字节码模糊器,其工作原理是用简单的条件跳转替换GOTO指令,比如说,if 10!=15转到其他操作引发非法状态异常。我目前的代码是: final AbstractInsnNode[] insns = method.instructions.toArray().clone(); for (final AbstractInsnNode insn : insns) { final int op = insn.getOpcode();
GOTO
指令,比如说,if 10!=15转到其他操作引发非法状态异常
。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);
}
}
我做了很多研究,我发现唯一的原因是:据我所知,问题是@21
上的堆栈(GOTO
,它跳到标签上,抛出新的非法状态异常
):
堆栈:{}
(为空)与跳转目标标签上@27
处的堆栈不匹配:
stack:{'java/lang/IllegalStateException'}
(其中包含它应该“抛出”的异常)
因此,基本上,据我所知,错误发生在我尝试执行转到
跳转时,其中
是“抛出”非法状态异常的标签号
如何解决此问题?也许有一种方法可以使
@21
中的堆栈在跳转之前也包含java/lang/IllegalStateException
(以便这两个堆栈,跳转之前的堆栈和跳转之后的堆栈匹配)?或者我可以用它做些什么?您正在指令后插入一个异常处理程序,但是当指令是一个条件分支时,即IFLE
或IFGE
,可能不会执行该分支,并且代码流在指令后继续,运行到异常处理程序中
这会创建一个不一致的状态,因为异常处理程序希望堆栈上出现一个可丢弃的
,而当指令插入后代码流继续时,堆栈上不存在该状态。但是,当然,在这种情况下,您不希望执行异常处理程序,因此如果我没有弄错,您必须插入另一个GOTO
,从l2
到l5
当检测GOTO
指令时,这不是一个问题,这些指令永远不会在指令之后继续
在这里,我推荐一种不同的编码风格。在不同的引用节点之前和之后插入,使得在读取代码时无法预测实际的代码结构。如果只使用一个引用节点插入指令的线性列表,那么它将更易于维护。在指令之后插入异常处理程序,但当指令是条件分支时,即
IFLE
或IFGE
,可能不会执行分支,并且代码流在指令之后继续,运行到异常处理程序中
这会创建一个不一致的状态,因为异常处理程序希望堆栈上出现一个可丢弃的
,而当指令插入后代码流继续时,堆栈上不存在该状态。但是,当然,在这种情况下,您不希望执行异常处理程序,因此如果我没有弄错,您必须插入另一个GOTO
,从l2
到l5
当检测GOTO
指令时,这不是一个问题,这些指令永远不会在指令之后继续
在这里,我推荐一种不同的编码风格。在不同的引用节点之前和之后插入,使得在读取代码时无法预测实际的代码结构。如果只使用一个引用节点插入一个线性指令列表,那么它的可维护性会更好。为什么要替换if操作码?我以为你只想替换gotos?为什么要替换if操作码?我以为你只想取代gotos?
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)