20chan / assemblysharp

Run x86 assembly with assembly macro-like syntax in C#

AssemblySharp

• English
• 한국어

Implementation of C/C++ __asm or __asm__ keywords as closely as possible in C#. Standard Intel syntax used in Microsoft Micro Assembler (MASM) assembler is supported.

Works on .Net core 2.1

Usage

int a = 200;
int result = (int)X86Assembly.ExecuteScript(
    ASM.MOV, REG.EAX, 100,
    ASM.ADD, REG.EAX, a,
    ASM.RET);
Console.WriteLine(result); // 300

int i = 100;
result = X86Assembly.ExecuteScript(
    ASM.mov, REG.EAX, 0,
    ASM.mov, REG.ECX, i,
    new Label("myloop"),
    ASM.add, REG.EAX, REG.ECX,
    ASM.loop, "myloop",
    ASM.ret));
Console.WriteLine(result); // 5050

Requirements

Should be installed gcc, objdump. You need to set your PATH environment variable to include directory of them.

LICENSE

The MIT License (MIT) Copyright (c) 2019 20chan

assemblysharp's Issues

Pass reference of operand to instruction

In AssemblySharp currently(894ebaa), registers are like

public dwordop EAX => _vm.EAX;
public dwordop EBX => _vm.EBX;
public dwordop ECX => _vm.ECX;
public dwordop EDX => _vm.EDX;

(I made type dwordop, wordop, byteop but it's useless)

And what I want to do is make this code work.

vm.Instrucment.MOV(vm.Registers.EAX, 3);

Type of EAX is Register, and it's same as uint type. That means, there's no way to know what is that operand. It's not problem only in registers, all of operands like segments and memory, etc.

Insert assembly to method body

By writing custom managed JIT, we can insert code into method body at runtime.

http://xoofx.com/blog/2018/04/12/writing-managed-jit-in-csharp-with-coreclr/

Migrate to .Net Standard 2.1

Better use .net standard

Type of delegate in RunMachineCode

Before 7cab4db X86Assembly.RunMachineCode was like this.

T RunMachineCode<T>(...)

In the issue #1 I was trying to declare delegate type of T in runtime, and use it as generic parameter of Marshal.GetDelegateForFunctionPointer but I gave up as you can see at d113692.

But all the types of returned value is not integer. This will make code more messy casting types.

Migrate to .NET Core

.Net Framework is gone ;(

Support Action/Func for return type

https://blog.adamfurmanek.pl/2018/03/24/generating-func-from-bunch-of-bytes-in-c/

Looks it could be possible

Add VM

Allocating memory and executing machine code is dangerous, and sometimes not working because CLR manages memory. VM executing machine code can do anything! 😄

feature request : support asm from string

reg somevar
reg someaddr
or reg some module base addr
-------------- so we can 
mov eax,0x1,
lea eax, somevar
jmp someaddr

GetDelegateForFunctionPointer의 델리게이트 타입 문제

컴파일타임에서 생성된 델리게이트를 제너릭 인수로 넣어야 하는데 반환값을 제너릭으로 지정하려다 보니 어떻게 할 수가 없음.

https://github.com/phillyai/AssemblySharp/blob/45fc0d554801dae966dfcbaa9d35935cb16095e4/AssemblySharp/X86Assembly.cs#L58

여기서 ObjectDelegate 타입도 안되고 Func도 안됨. 당연히 object나 dynamic고 Delegate를 상속하지 않아 안됨.

AccessViolationException when using register or memory

In current version, System.AccessViolationException throwed when I use register ebx or push something.
I thought it's problem allocating memory using VirtualAlloc, so I changed that part like this.

var buffer = Marshal.AllocCoTaskMem(bytecode.Length);
// var buffer = WinAPI.VirtualAlloc(IntPtr.Zero, (uint)bytecode.Length, WinAPI.AllocationType.Commit, WinAPI.MemoryProtection.ExecuteReadWrite);

I tried to use Marshal.AllocCoTaskMem instead of VirtualAlloc, and I ran some test cases. When I access ANY of registers it throwed AccessViolationException. It was much worse.

Is there any way to use " unsafe " memory/register accessing?