DynamicInvoke of native functions using GetProcAddress

DynamicInvokeExample.cs

using System.Diagnostics;
using System.Text;
using System;
using System.Runtime.InteropServices;

namespace Code_Projects
{
    public static class DynamicInvokeExample
    {

        [DllImport("kernel32", CharSet = CharSet.Ansi, ExactSpelling = true, SetLastError = true)]
        private static extern IntPtr GetProcAddress(IntPtr hModule, string procName);

        [UnmanagedFunctionPointer(CallingConvention.StdCall)]
        private delegate uint PVM(IntPtr ProcessHandle, ref IntPtr BaseAddress, ref uint numberOfBytes,
        uint newProtect, out uint oldProtect);

        public static IntPtr GetLoadedModuleAddress(string dllName)
        {
            var procModules = Process.GetCurrentProcess().Modules;
            foreach (ProcessModule mod in procModules)
            {
                if (mod.ModuleName != dllName)
                    continue;
                return mod.BaseAddress;
            }
            return IntPtr.Zero;
        }

        private static IntPtr GetFunctionPointer(string dllName, string functionName)
        {
            var hModule = GetLoadedModuleAddress(dllName);
            return GetProcAddress(hModule, functionName);
        }

        public static void Protect()
        {
            string dllName = Encoding.UTF8.GetString(Convert.FromBase64String("bnRkbGwuZGxs")); // ntdll.dll
            string functionName = Encoding.UTF8.GetString(Convert.FromBase64String("TnRQcm90ZWN0VmlydHVhbE1lbW9yeQ==")); // NtProtectVirtualMemory
            var fPointer = GetFunctionPointer(dllName, functionName);
            PVM pvm = Marshal.GetDelegateForFunctionPointer<PVM>(fPointer);

            var p = Process.GetCurrentProcess();
            var @base = p.MainModule.BaseAddress;

            uint size = 0x3C;

            pvm(p.Handle, ref @base, ref size, 0x04, out uint oldProtect);

            Marshal.Copy(new byte[size], 0, @base, (int)size);

            pvm(p.Handle, ref @base, ref size, oldProtect, out _);
        }
    }
}

This example invokes NtProtectVirtualMemory from ntdll.dll
The delegate PVM is specifically for NtProtectVirtualMemory