VMP 简单源码分析（.net）

虚拟机

获取CPU的型号
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实现了一个指令集解释器，每个操作码对应一个特定的处理函数，用于执行相应的指令操作。在执行字节码时，解释器会根据操作码查找并调用相应的处理函数来执行指令。
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截获异常先由虚拟机处理处理不了再抛出异常

		private void Unwind(){_stack.Clear();_finallyStack.Clear();while (_tryStack.Count != 0){var catchBlocks = _tryStack.Peek().CatchBlocks();int startIndex = (_filterBlock == null) ? 0 : catchBlocks.IndexOf(_filterBlock) + 1;_filterBlock = null;for (var i = startIndex; i < catchBlocks.Count; i++){var current = catchBlocks[i];switch (current.Type()){case 0:var type = _exception.GetType();var type2 = GetType(current.Filter());if (type == type2 || type.IsSubclassOf(type2)){_tryStack.Pop();_stack.Push(new ObjectVariant(_exception));_pos = current.Handler();return;}break;case 1:_filterBlock = current;_stack.Push(new ObjectVariant(_exception));_pos = current.Filter();return;}}_tryStack.Pop();for (var i = catchBlocks.Count; i > 0; i--){var current = catchBlocks[i - 1];if (current.Type() == 2 || current.Type() == 4)_finallyStack.Push(current.Handler());}if (_finallyStack.Count != 0){_pos = _finallyStack.Pop();return;}}throw _exception;}

检查运算数据的类型
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根据数据判断实现无符号运算以及运算溢出等的处理
同理的还有异或减法等

		private BaseVariant Add(BaseVariant v1, BaseVariant v2, bool ovf, bool un){var type = CalcTypeCode(v1, v2);switch (type){case TypeCode.Int32:{int value;if (un){var value1 = v1.ToUInt32();var value2 = v2.ToUInt32();value = ovf ? (int)checked(value1 + value2) : (int)(value1 + value2);}else{var value1 = v1.ToInt32();var value2 = v2.ToInt32();value = ovf ? checked(value1 + value2) : (value1 + value2);}return new IntVariant(value);}case TypeCode.Int64:{long value;if (un){var value1 = v1.ToUInt64();var value2 = v2.ToUInt64();value = ovf ? (long)checked(value1 + value2) : (long)(value1 + value2);}else{var value1 = v1.ToInt64();var value2 = v2.ToInt64();value = ovf ? checked(value1 + value2) : (value1 + value2);}return new LongVariant(value);}case TypeCode.Single:{var value1 = (un ? v1.ToUnsigned() : v1).ToSingle();var value2 = (un ? v2.ToUnsigned() : v2).ToSingle();return new SingleVariant(ovf ? checked(value1 + value2) : (value1 + value2));}case TypeCode.Double:{var value1 = (un ? v1.ToUnsigned() : v1).ToDouble();var value2 = (un ? v2.ToUnsigned() : v2).ToDouble();return new DoubleVariant(ovf ? checked(value1 + value2) : (value1 + value2));}case TypeCode.UInt32:{int value;if (un){var value1 = v1.ToUInt32();var value2 = v2.ToUInt32();value = ovf ? (int)checked(value1 + value2) : (int)(value1 + value2);}else{var value1 = v1.ToInt32();var value2 = v2.ToInt32();value = ovf ? checked(value1 + value2) : (value1 + value2);}PointerVariant v = v1.CalcTypeCode() == type ? (PointerVariant)v1 : (PointerVariant)v2;unsafe{return new PointerVariant(Pointer.Box(new IntPtr(value).ToPointer(), v.Type()), v.Type());}}case TypeCode.UInt64:{long value;if (un){var value1 = v1.ToUInt64();var value2 = v2.ToUInt64();value = ovf ? (long)checked(value1 + value2) : (long)(value1 + value2);}else{var value1 = v1.ToInt64();var value2 = v2.ToInt64();value = ovf ? checked(value1 + value2) : (value1 + value2);}PointerVariant v = v1.CalcTypeCode() == type ? (PointerVariant)v1 : (PointerVariant)v2;unsafe{return new PointerVariant(Pointer.Box(new IntPtr(value).ToPointer(), v.Type()), v.Type());}}}throw new InvalidOperationException();}

获取目标程序框架
设置调用方法
支持实例方法、静态方法、虚拟方法和过滤方法

		private BaseVariant Call(MethodBase method, bool virt){BindingFlags invokeFlags;
#if NETCOREAPPinvokeFlags = BindingFlags.DoNotWrapExceptions;
#elseinvokeFlags = BindingFlags.Default;
#endifvar info = method as MethodInfo;var parameters = method.GetParameters();var refs = new Dictionary<int, BaseVariant>();var args = new object[parameters.Length];BaseVariant v;for (var i = parameters.Length - 1; i >= 0; i--){v = Pop();if (v.IsReference())refs[i] = v;args[i] = Convert(v, parameters[i].ParameterType).Value();}v = method.IsStatic ? null : Pop();object obj = v?.Value() ?? null;if (virt && obj == null)throw new NullReferenceException();object res = null;if (method.IsConstructor && method.DeclaringType.IsValueType){obj = Activator.CreateInstance(method.DeclaringType, invokeFlags, null, args, null);if (v != null && v.IsReference())v.SetValue(Convert(obj, method.DeclaringType).Value());}else if (!IsFilteredMethod(method, obj, ref res, args)){if (!virt && method.IsVirtual && !method.IsFinal){DynamicMethod dynamicMethod;var paramValues = new object[parameters.Length + 1];paramValues[0] = obj;for (var i = 0; i < parameters.Length; i++){paramValues[i + 1] = args[i];}lock (_dynamicMethodCache){if (!_dynamicMethodCache.TryGetValue(method, out dynamicMethod)){var paramTypes = new Type[paramValues.Length];paramTypes[0] = method.DeclaringType;for (var i = 0; i < parameters.Length; i++){paramTypes[i + 1] = parameters[i].ParameterType;}dynamicMethod = new DynamicMethod("", info != null && info.ReturnType != typeof(void) ? info.ReturnType : null, paramTypes, typeof(VirtualMachine).Module, true);var gen = dynamicMethod.GetILGenerator();gen.Emit(v.IsReference() ? System.Reflection.Emit.OpCodes.Ldarga : System.Reflection.Emit.OpCodes.Ldarg, 0);for (var i = 1; i < paramTypes.Length; i++){gen.Emit(refs.ContainsKey(i - 1) ? System.Reflection.Emit.OpCodes.Ldarga : System.Reflection.Emit.OpCodes.Ldarg, i);}gen.Emit(System.Reflection.Emit.OpCodes.Call, info);gen.Emit(System.Reflection.Emit.OpCodes.Ret);_dynamicMethodCache[method] = dynamicMethod;}}res = dynamicMethod.Invoke(null, invokeFlags, null, paramValues, null);foreach (var r in refs){r.Value.SetValue(paramValues[r.Key + 1]);}refs.Clear();}else{res = method.Invoke(obj, invokeFlags, null, args, null);}}foreach (var r in refs){r.Value.SetValue(args[r.Key]);}return (info != null && info.ReturnType != typeof(void)) ? Convert(res, info.ReturnType) : null;}

字符串管理

构造字典
在字典中得到字符串偏移经过解密后返回字符串

		public string DecryptString(uint stringId){uint pos;if (_entries.TryGetValue(stringId, out pos)){var entry = new byte[16];Marshal.Copy(new IntPtr(_instance + pos), entry, 0, 16);entry = _cipher.Decrypt(entry);var size = BitConverter.ToInt32(entry, 8);var stringData = new byte[size];Marshal.Copy(new IntPtr(_instance + BitConverter.ToUInt32(entry, 4)), stringData, 0, size);for (var c = 0; c < size; c++){stringData[c] = (byte)(stringData[c] ^ BitRotate.Left(_key, c) + c);}return Encoding.Unicode.GetString(stringData);}return null;}