Availability check of a network path with credentials

Question

In C# I would like test the availability of a network path, what authentication needed. I am using the following function:

    private bool TestDrive(string path,string userName,string domain, string password)
    {
        if (userName == "")
            return true;
        //else authentication needed
        try
        {
            using (new CImpersonator(userName, domain, password))
            {
                using (FileStream fs = File.Create(path+"\\1.txt"))
                { }
                File.Delete(path + "\\1.txt");
            }
            return true;
        }
        catch (Exception ex)
        {
            return false;
        }
    }

public CImpersonator(
        string userName,
        string domainName,
        string password,
        bool checkUserName = true)
    {
        //Check if user exists
        if (checkUserName && !CCheckUsername.UserExists(userName))
                return;

        this.ImpersonateValidUser(userName, domainName, password);
    }

private void ImpersonateValidUser(
        string userName,
        string domain,
        string password)
    {
        WindowsIdentity tempWindowsIdentity = null;
        IntPtr token = IntPtr.Zero;
        IntPtr tokenDuplicate = IntPtr.Zero;

        try
        {
            if (RevertToSelf())
            {
                if (LogonUser(
                    userName,
                    domain,
                    password,
                    LOGON32_LOGON_INTERACTIVE,
                    LOGON32_PROVIDER_DEFAULT,
                    ref token) != 0)
                {
                    if (DuplicateToken(token, (int)System.Management.ImpersonationLevel.Impersonate, ref tokenDuplicate) != 0)
                    {
                        tempWindowsIdentity = new WindowsIdentity(tokenDuplicate);
                        _impersonationContext = tempWindowsIdentity.Impersonate();
                        bool retVal;
                        TokPriv1Luid tp;
                        IntPtr hproc = (IntPtr)System.Diagnostics.Process.GetCurrentProcess().Id;
                        IntPtr htok = IntPtr.Zero;
                        retVal = OpenProcessToken(hproc, TOKEN_ALL_ACCESS, ref htok);
                        tp.Count = 1;
                        tp.Luid = 0;
                        tp.Attr = SE_PRIVILEGE_ENABLED;
                        retVal = LookupPrivilegeValue(null, SE_SYSTEMTIME_NAME, ref tp.Luid);
                        retVal = AdjustTokenPrivileges(token, false, ref tp, Marshal.SizeOf(typeof(TokPriv1Luid)), IntPtr.Zero, IntPtr.Zero);
                    }
                    else
                    {
                        throw new Win32Exception(Marshal.GetLastWin32Error());
                    }
                }
                else
                {
                    throw new Win32Exception(Marshal.GetLastWin32Error());
                }
            }
            else
            {
                throw new Win32Exception(Marshal.GetLastWin32Error());
            }
        }
        finally
        {
            if (token != IntPtr.Zero)
            {
                CloseHandle(token);
            }
            if (tokenDuplicate != IntPtr.Zero)
            {
                CloseHandle(tokenDuplicate);
            }
        }
    }

The problem is that when I use this for test a network path in an another domain, then the TestDrive function returns false. Of course the domain, username and password are good, the user rights are good.

It is strange that the function works good, when I test it in the same domain.

Thank you for all ideas!

score 0 · Answer 1 · edited May 23 '17 at 12:21

I would first try the following:

Folder.Exists(String Path);

This will however only work on a Path where you have read access, so if the network path isn't mapped with the credentials this method will return false, but you can use the above method and if it returns false, map the network path (this question answersthe how-to on that) with those different credentials

and then perform the:

Folder.Exists(String Path);

once more. Afterwards you can disconnect the network drive again.

Availability check of a network path with credentials

1 Answers1