C#: How to logon to a share when using DirectoryInfo

Question

If I want to instantiate a DirectoryInfo object with an UNC path

DirectoryInfo myDI = new DirectoryInfo (@"\\server\share");

how can I pass a username / password that is required to access that share?

Thanks

Kovrov

Answer 1

In .NET 4 this class works perfectly for me to logon in none windows server via UNC.

using Microsoft.VisualBasic;
using System;
using System.Collections;
using System.Collections.Generic;
using System.Data;
using System.Diagnostics;
using System.Linq;
using System.Web;
using System.Runtime.InteropServices;
using System.Security.Principal;
using System.Web.Security;


namespace toolsforimpersonations
{
    public class Impersonator
    {
        #region "Consts"

        public const int LOGON32_LOGON_INTERACTIVE = 2;

        public const int LOGON32_PROVIDER_DEFAULT = 0;
        #endregion

        #region "External API"
        [DllImport("advapi32.dll", SetLastError = true)]
        public static extern int LogonUser(string lpszUsername, string lpszDomain, string lpszPassword, int dwLogonType, int dwLogonProvider, ref IntPtr phToken);

        [DllImport("advapi32.dll", SetLastError = true)]
        public static extern bool RevertToSelf();

        [DllImport("kernel32.dll", SetLastError = true)]
        public static extern int CloseHandle(IntPtr hObject);

        #endregion

        #region "Methods"

        //Public Sub PerformImpersonatedTask(ByVal username As String, ByVal domain As String, ByVal password As String, ByVal logonType As Integer, ByVal logonProvider As Integer, ByVal methodToPerform As Action)
        public void PerformImpersonatedTask(string username, string domain, string password, int logonType, int logonProvider, Action methodToPerform)
        {
            IntPtr token = IntPtr.Zero;
            if (RevertToSelf()) {
                if (LogonUser(username, domain, password, logonType, logonProvider, ref token) != 0) {
                    dynamic identity = new WindowsIdentity(token);
                    dynamic impersonationContext = identity.Impersonate();
                    if (impersonationContext != null) {
                        methodToPerform.Invoke();
                        impersonationContext.Undo();
                    }
                // do logging
                } else {
                }
            }
            if (token != IntPtr.Zero) {
                CloseHandle(token);
            }
        }

        #endregion
    }

    public class UserImpersonation
    {
        const int  LOGON32_LOGON_INTERACTIVE = 2;
        const int  LOGON32_LOGON_NETWORK = 3;
        const int  LOGON32_LOGON_BATCH = 4;
        const int  LOGON32_LOGON_SERVICE = 5;
        const int  LOGON32_LOGON_UNLOCK = 7;
        const int  LOGON32_LOGON_NETWORK_CLEARTEXT = 8;
        const int  LOGON32_LOGON_NEW_CREDENTIALS = 9;
        const int  LOGON32_PROVIDER_DEFAULT = 0;
        const int  LOGON32_PROVIDER_WINNT35 = 1;
        const int  LOGON32_PROVIDER_WINNT40 = 2;
        const int  LOGON32_PROVIDER_WINNT50 = 3;

        WindowsImpersonationContext impersonationContext;
        [DllImport("advapi32.dll", CharSet = CharSet.Ansi, SetLastError = true, ExactSpelling = true)]
        public static extern int LogonUserA(string lpszUsername, string lpszDomain, string lpszPassword, int dwLogonType, int dwLogonProvider, ref IntPtr phToken);
        [DllImport("advapi32.dll", CharSet = CharSet.Auto, SetLastError = true, ExactSpelling = true)]

        public static extern int DuplicateToken(IntPtr ExistingTokenHandle, int ImpersonationLevel, ref IntPtr DuplicateTokenHandle);
        [DllImport("advapi32.dll", CharSet = CharSet.Auto, SetLastError = true, ExactSpelling = true)]

        public static extern long RevertToSelf();
        [DllImport("kernel32.dll", CharSet = CharSet.Auto, SetLastError = true, ExactSpelling = true)]
        public static extern long CloseHandle(IntPtr handle);

        public bool impersonateUser(string userName, string domain, string password)
        {
            return impersonateValidUser(userName, domain, password);
        }

        public void undoimpersonateUser()
        {
            undoImpersonation();
        }

        private bool impersonateValidUser(string userName, string domain, string password)
        {
            bool functionReturnValue = false;

            WindowsIdentity tempWindowsIdentity = null;
            IntPtr token = IntPtr.Zero;
            IntPtr tokenDuplicate = IntPtr.Zero;
            functionReturnValue = false;

            //if (RevertToSelf()) {
                if (LogonUserA(userName, domain, password, LOGON32_LOGON_NEW_CREDENTIALS, LOGON32_PROVIDER_WINNT50, ref token) != 0) {
                    if (DuplicateToken(token, 2, ref tokenDuplicate) != 0) {
                        tempWindowsIdentity = new WindowsIdentity(tokenDuplicate);
                        impersonationContext = tempWindowsIdentity.Impersonate();
                        if ((impersonationContext != null)) {
                            functionReturnValue = true;
                        }
                    }
                }
            //}
            if (!tokenDuplicate.Equals(IntPtr.Zero)) {
                CloseHandle(tokenDuplicate);
            }
            if (!token.Equals(IntPtr.Zero)) {
                CloseHandle(token);
            }
            return functionReturnValue;
        }

        private void undoImpersonation()
        {
            impersonationContext.Undo();
        }

    }
}

And this is how to use from your programm

UserImpersonation impersonator = new UserImpersonation();
        impersonator.impersonateUser("username", "", "password"); //No Domain is required

        List<FileInfo> OcDialerlfinfo = null;
        OcDialerlfinfo = GetFileList("*", "\\\\10.11.11.122\\shared_folder");
        impersonator.undoimpersonateUser();

and for the sake of the test you need to use this little function to list all the files in the directory

public static List<FileInfo> GetFileList(string fileSearchPattern, string rootFolderPath)
        {
            DirectoryInfo rootDir = new DirectoryInfo(rootFolderPath);

            List<DirectoryInfo> dirList = new List<DirectoryInfo>(rootDir.GetDirectories("*", SearchOption.AllDirectories));
            dirList.Add(rootDir);

            List<FileInfo> fileList = new List<FileInfo>();

            foreach (DirectoryInfo dir in dirList)
            {
                fileList.AddRange(dir.GetFiles(fileSearchPattern, SearchOption.TopDirectoryOnly));
            }

            return fileList;
        }

Jacoby

This appears very similar to this Microsoft support article (on impersonation in ASP.NET, though it applies outside web apps as well). Your sample code was more helpful for general use. – Erv

Answer 2

Try this approach:

using System;
using System.ComponentModel;
using System.Runtime.InteropServices;
using System.Security.Principal;

namespace Tools.Network
{
 public enum LogonType
 {
  LOGON32_LOGON_INTERACTIVE = 2,
  LOGON32_LOGON_NETWORK = 3,
  LOGON32_LOGON_BATCH = 4,
  LOGON32_LOGON_SERVICE = 5,
  LOGON32_LOGON_UNLOCK = 7,
  LOGON32_LOGON_NETWORK_CLEARTEXT = 8, // Win2K or higher
  LOGON32_LOGON_NEW_CREDENTIALS = 9 // Win2K or higher
 };

 public enum LogonProvider
 {
  LOGON32_PROVIDER_DEFAULT = 0,
  LOGON32_PROVIDER_WINNT35 = 1,
  LOGON32_PROVIDER_WINNT40 = 2,
  LOGON32_PROVIDER_WINNT50 = 3
 };

 public enum ImpersonationLevel
 {
  SecurityAnonymous = 0,
  SecurityIdentification = 1,
  SecurityImpersonation = 2,
  SecurityDelegation = 3
 }

 class Win32NativeMethods
 {
  [DllImport("advapi32.dll", SetLastError = true)]
  public static extern int LogonUser( string lpszUserName,
       string lpszDomain,
       string lpszPassword,
       int dwLogonType,
       int dwLogonProvider,
       ref IntPtr phToken);

  [DllImport("advapi32.dll", CharSet = CharSet.Auto, SetLastError = true)]
  public static extern int DuplicateToken( IntPtr hToken,
        int impersonationLevel,
        ref IntPtr hNewToken);

  [DllImport("advapi32.dll", CharSet = CharSet.Auto, SetLastError = true)]
  public static extern bool RevertToSelf();

  [DllImport("kernel32.dll", CharSet = CharSet.Auto)]
  public static extern bool CloseHandle(IntPtr handle);
 }

 /// <summary>
 /// Allows code to be executed under the security context of a specified user account.
 /// </summary>
 /// <remarks> 
 ///
 /// Implements IDispose, so can be used via a using-directive or method calls;
 ///  ...
 ///
 ///  var imp = new Impersonator( "myUsername", "myDomainname", "myPassword" );
 ///  imp.UndoImpersonation();
 ///
 ///  ...
 ///
 ///   var imp = new Impersonator();
 ///  imp.Impersonate("myUsername", "myDomainname", "myPassword");
 ///  imp.UndoImpersonation();
 ///
 ///  ...
 ///
 ///  using ( new Impersonator( "myUsername", "myDomainname", "myPassword" ) )
 ///  {
 ///   ...
 ///   [code that executes under the new context]
 ///   ...
 ///  }
 ///
 ///  ...
 /// </remarks>
 public class Impersonator : IDisposable
 {
  private WindowsImpersonationContext _wic;

  /// <summary>
  /// Begins impersonation with the given credentials, Logon type and Logon provider.
  /// </summary>
  ///
<param name="userName">Name of the user.</param>
  ///
<param name="domainName">Name of the domain.</param>
  ///
<param name="password">The password. <see cref="System.String"/></param>
  ///
<param name="logonType">Type of the logon.</param>
  ///
<param name="logonProvider">The logon provider. <see cref="Mit.Sharepoint.WebParts.EventLogQuery.Network.LogonProvider"/></param>
  public Impersonator(string userName, string domainName, string password, LogonType logonType, LogonProvider logonProvider)
  {
   Impersonate(userName, domainName, password, logonType, logonProvider);
  }

  /// <summary>
  /// Begins impersonation with the given credentials.
  /// </summary>
  ///
<param name="userName">Name of the user.</param>
  ///
<param name="domainName">Name of the domain.</param>
  ///
<param name="password">The password. <see cref="System.String"/></param>
  public Impersonator(string userName, string domainName, string password)
  {
   Impersonate(userName, domainName, password, LogonType.LOGON32_LOGON_INTERACTIVE, LogonProvider.LOGON32_PROVIDER_DEFAULT);
  }

  /// <summary>
  /// Initializes a new instance of the <see cref="Impersonator"/> class.
  /// </summary>
  public Impersonator()
  {}

  /// <summary>
  /// Performs application-defined tasks associated with freeing, releasing, or resetting unmanaged resources.
  /// </summary>
  public void Dispose()
  {
   UndoImpersonation();
  }

  /// <summary>
  /// Impersonates the specified user account.
  /// </summary>
  ///
<param name="userName">Name of the user.</param>
  ///
<param name="domainName">Name of the domain.</param>
  ///
<param name="password">The password. <see cref="System.String"/></param>
  public void Impersonate(string userName, string domainName, string password)
  {
   Impersonate(userName, domainName, password, LogonType.LOGON32_LOGON_INTERACTIVE, LogonProvider.LOGON32_PROVIDER_DEFAULT);
  }

  /// <summary>
  /// Impersonates the specified user account.
  /// </summary>
  ///
<param name="userName">Name of the user.</param>
  ///
<param name="domainName">Name of the domain.</param>
  ///
<param name="password">The password. <see cref="System.String"/></param>
  ///
<param name="logonType">Type of the logon.</param>
  ///
<param name="logonProvider">The logon provider. <see cref="Mit.Sharepoint.WebParts.EventLogQuery.Network.LogonProvider"/></param>
  public void Impersonate(string userName, string domainName, string password, LogonType logonType, LogonProvider logonProvider)
  {
   UndoImpersonation();

   IntPtr logonToken = IntPtr.Zero;
   IntPtr logonTokenDuplicate = IntPtr.Zero;
   try
   {
    // revert to the application pool identity, saving the identity of the current requestor
    _wic = WindowsIdentity.Impersonate(IntPtr.Zero);

    // do logon & impersonate
    if (Win32NativeMethods.LogonUser(userName,
        domainName,
        password,
        (int)logonType,
        (int)logonProvider,
        ref logonToken) != 0)
    {
     if (Win32NativeMethods.DuplicateToken(logonToken, (int)ImpersonationLevel.SecurityImpersonation, ref logonTokenDuplicate) != 0)
     {
      var wi = new WindowsIdentity(logonTokenDuplicate);
      wi.Impersonate(); // discard the returned identity context (which is the context of the application pool)
     }
     else
      throw new Win32Exception(Marshal.GetLastWin32Error());
    }
    else
     throw new Win32Exception(Marshal.GetLastWin32Error());
   }
   finally
   {
    if (logonToken != IntPtr.Zero)
     Win32NativeMethods.CloseHandle(logonToken);

    if (logonTokenDuplicate != IntPtr.Zero)
     Win32NativeMethods.CloseHandle(logonTokenDuplicate);
   }
  }

  /// <summary>
  /// Stops impersonation.
  /// </summary>
  private void UndoImpersonation()
  {
   // restore saved requestor identity
   if (_wic != null)
    _wic.Undo();
   _wic = null;
  }
 }
}

Whoop