BoTW-Multiplayer/C#/GUIApp/Classes/Injector.cs

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.IO;
using System.Runtime.InteropServices;
using System.Diagnostics;

namespace GUIApp
{
    public class Injector
    {

        static readonly IntPtr INTPTR_ZERO = (IntPtr)0;
        [DllImport("kernel32.dll", SetLastError = true)]
        static extern IntPtr OpenProcess(uint dwDesiredAccess, int bInheritHandle, uint dwProcessId);
        [DllImport("kernel32.dll", SetLastError = true)]
        static extern int CloseHandle(IntPtr hObject);
        [DllImport("kernel32.dll", SetLastError = true)]
        static extern IntPtr GetProcAddress(IntPtr hModule, string lpProcName);
        [DllImport("kernel32.dll", CharSet = CharSet.Auto, SetLastError = true)]
        static extern IntPtr GetModuleHandle(string lpModuleName);
        [DllImport("kernel32.dll", SetLastError = true)]
        static extern IntPtr VirtualAllocEx(IntPtr hProcess, IntPtr lpAddress, IntPtr dwSize, uint flAllocationType, uint flProtect);
        [DllImport("kernel32.dll", SetLastError = true)]
        static extern int WriteProcessMemory(IntPtr hProcess, IntPtr lpBaseAddress, byte[] buffer, uint size, int lpNumberOfBytesWritten);
        [DllImport("kernel32.dll", SetLastError = true)]
        static extern IntPtr CreateRemoteThread(IntPtr hProcess, IntPtr lpThreadAttributes, uint dwStackSize, IntPtr lpStartAddress, IntPtr lpParameter, uint dwCreationFlags, IntPtr lpThreadId);

        Form1 MainWindow;

        public Injector(Form1 sender)
        {
            this.MainWindow = sender;
        }

        public bool SI(uint P, string DLLP)
        {
            IntPtr hndProc = OpenProcess((0x2 | 0x8 | 0x10 | 0x20 | 0x400), 1, P);

            if (hndProc == INTPTR_ZERO) { return false; }

            IntPtr lpAddress = VirtualAllocEx(hndProc, (IntPtr)null, (IntPtr)DLLP.Length, (0x1000 | 0x2000), 0x40);

            if (lpAddress == INTPTR_ZERO)
            {
                return false;
            }

            byte[] bytes = Encoding.ASCII.GetBytes(DLLP);

            if (WriteProcessMemory(hndProc, lpAddress, bytes, (uint)bytes.Length, 0) == 0)
            {
                return false;
            }

            IntPtr loadlibAddy = GetProcAddress(GetModuleHandle("kernel32.dll"), "LoadLibraryA");
            

            IntPtr hThread = CreateRemoteThread(hndProc, IntPtr.Zero, 0, loadlibAddy, lpAddress, 0, IntPtr.Zero);

            CloseHandle(hThread);

            return true;

        }

        public int injectDLL(string PN, string DLLP)
        {

            if (!File.Exists(DLLP)){ return 1; }

            uint _procId = 0;
            Process[] _procs = Process.GetProcesses();
            
            for (int i = 0; i < _procs.Length; i++)
            {
                if (_procs[i].ProcessName == PN)
                {
                    _procId = (uint)_procs[i].Id;
                }
            }

            if (_procId == 0) { return 2; }

            if (!SI(_procId, DLLP))
            {
                return 3;
            }

            return 4;
 
        }

    }
}