C# How to change user context in app running on system - c#

I have an application that runs with the system user. I need that some code in the app runs on user context (with the user itself). For example i need to use the webclient in user context because that way my firewall recognize the username, but later i need to run some other code ex. Running a exe in system context (with system user) because i need the privileges.
Is there a way to do this?.
Thanks!!!

I have used this code to impersonate certain operations
using System;
using System.ComponentModel;
using System.Runtime.InteropServices;
using System.Security.Principal;
using NLog;
namespace Core.Impersonation
{
public class ImpersonatedUser : IDisposable
{
private static Logger logger = LogManager.GetCurrentClassLogger();
IntPtr userHandle;
WindowsImpersonationContext impersonationContext;
public ImpersonatedUser(string user, string domain, string password)
{
logger.Debug("Impersonating user: " + domain + #"\" + user);
userHandle = IntPtr.Zero;
bool loggedOn = LogonUser(
user,
domain,
password,
LogonType.Interactive,
LogonProvider.Default,
out userHandle);
if (!loggedOn)
throw new Win32Exception(Marshal.GetLastWin32Error());
// Begin impersonating the user
impersonationContext = WindowsIdentity.Impersonate(userHandle);
}
public void Dispose()
{
if (userHandle != IntPtr.Zero)
{
CloseHandle(userHandle);
userHandle = IntPtr.Zero;
impersonationContext.Undo();
logger.Debug("Finished Impersonating user");
}
}
[DllImport("advapi32.dll", SetLastError = true)]
static extern bool LogonUser(
string lpszUsername,
string lpszDomain,
string lpszPassword,
LogonType dwLogonType,
LogonProvider dwLogonProvider,
out IntPtr phToken
);
[DllImport("kernel32.dll", SetLastError = true)]
static extern bool CloseHandle(IntPtr hHandle);
enum LogonType : int
{
Interactive = 2,
Network = 3,
Batch = 4,
Service = 5,
NetworkCleartext = 8,
NewCredentials = 9,
}
enum LogonProvider : int
{
Default = 0,
}
}
}
and then usage:
using (var i = new ImpersonatedUser("someLogin", "someDomain", "thePassword"))
{
var u = System.Environment.UserName;
}

Related

How deleted, replaced file at share folder

Hello I have a problem with deleting and replacing files at share folder
I have full access.
"access to the path was denied"
The copy function works well in both directions.
(but I have to delete files manually).
SERVER - >>> PC
SERVER <<< - PC
The program connects to the file server under another user and manipulate with files (copy files worked fine, delete files doesn't work replace doesn't work).
private void replaceFile(string source, string sourceName ,string destination)
{
try
{
using (new Impersonator(username(), domain(), password()))
{
//File.delete(destination);
//File.Copy(source, destination, true);
File.Replace(source, destination, null);
}
}
catch (Exception e)
{
MessageBox.Show(e.Message);
}
}
private void copyFile(string source, string destination)
{
try
{
using (new Impersonator(username(), domain(), password()))
{
File.Copy(source, destination, true);
}
}
catch (Exception e)
{
MessageBox.Show(e.Message);
}
}
using System;
using System.ComponentModel;
using System.Runtime.InteropServices;
using System.Security.Principal;
using System.Windows.Forms;
namespace IFS_FileManager
{
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);
}
public class Impersonator : IDisposable
{
private WindowsImpersonationContext _wic;
public Impersonator(string userName, string domainName, string password, LogonType logonType, LogonProvider logonProvider)
{
Impersonate(userName, domainName, password, logonType, logonProvider);
}
public Impersonator(string userName, string domainName, string password)
{
Impersonate(userName, domainName, password, LogonType.LOGON32_LOGON_INTERACTIVE, LogonProvider.LOGON32_PROVIDER_DEFAULT);
}
public Impersonator() { }
public void Dispose()
{
UndoImpersonation();
}
public void Impersonate(string userName, string domainName, string password)
{
Impersonate(userName, domainName, password, LogonType.LOGON32_LOGON_INTERACTIVE, LogonProvider.LOGON32_PROVIDER_DEFAULT);
}
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
MessageBox.Show("\n " + Marshal.GetLastWin32Error(), "Error Message", MessageBoxButtons.OK, MessageBoxIcon.Error);
}
else
MessageBox.Show("\n " + Marshal.GetLastWin32Error(), "Error Message", MessageBoxButtons.OK, MessageBoxIcon.Error);
}
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;
}
}
}

asp.net Access to the path XXX is denied

I've read tons of articles about this error.. also trying to set the folder's permission to the lowest:
But I still getting the error: Access to the path '\servername\shareFolder$\folderNameWeWantToCreate' is denied.
I am trying to check whether a directory exists and try to create a directory if not using the below code:
string Folderpath = #"\\servername\shareFolder$\folderNameWeWantToCreate";
if (!Directory.Exists(FolderPath))
Directory.CreateDirectory(FolderPath);
The above code works well on local, but the error comes out when put on to the server.
Is there anything I did wrong??
You have to impersonate identity for user
http://technet.microsoft.com/en-us/library/cc730708%28v=ws.10%29.aspx
There are two possible solutions:
Application Pool Identity
You need to create a new Application Pool in IIS that runs as the LocalSystem user and change your application to run on that AppPool. You need a high privilege user to do stuff on the local HD anyway and this'll save you a lot of permission slinging. In the future if you want to harden security you can always go back to a low privilege AppPool and just grant it permissions wherever it needs them.
Remote User Impersonation
If the above doesn't work, this is your recourse. It seems tricky but the code I'm running works perfectly on ASP.NET MVC 5 / .NET 4.5.1 so it should run fine on older versions too. Here's the code:
Helper classes:
public class ImpersonationHelper
{
[DllImport("advapi32.dll", SetLastError = true, CharSet = CharSet.Unicode)]
public static extern bool LogonUser(String lpszUsername, String lpszDomain, String lpszPassword,
int dwLogonType, int dwLogonProvider, out SafeTokenHandle phToken);
[DllImport("kernel32.dll", CharSet = CharSet.Auto)]
public extern static bool CloseHandle(IntPtr handle);
public const int LOGON32_PROVIDER_DEFAULT = 0;
public const int LOGON32_PROVIDER_WINNT50 = 3;
public const int LOGON32_PROVIDER_WINNT40 = 2;
public const int LOGON32_PROVIDER_WINNT35 = 1;
public const int LOGON32_LOGON_INTERACTIVE = 2;
public const int LOGON32_LOGON_NETWORK = 3;
public const int LOGON32_LOGON_NEW_CREDENTIALS = 9;
public static SafeTokenHandle GetSafeTokenHandle(string userName, string password, string domain)
{
SafeTokenHandle safeTokenHandle;
bool returnValue = LogonUser(userName, domain, password,
LOGON32_LOGON_NEW_CREDENTIALS, LOGON32_PROVIDER_WINNT50,
out safeTokenHandle);
if (false == returnValue)
{
int ret = Marshal.GetLastWin32Error();
throw new System.ComponentModel.Win32Exception(ret);
}
return safeTokenHandle;
}
}
public sealed class SafeTokenHandle : SafeHandleZeroOrMinusOneIsInvalid
{
private SafeTokenHandle()
: base(true)
{
}
[DllImport("kernel32.dll")]
[ReliabilityContract(Consistency.WillNotCorruptState, Cer.Success)]
[SuppressUnmanagedCodeSecurity]
[return: MarshalAs(UnmanagedType.Bool)]
private static extern bool CloseHandle(IntPtr handle);
protected override bool ReleaseHandle()
{
return CloseHandle(handle);
}
}
Main code:
var remoteUser = ConfigurationManager.AppSettings["RemoteUser"];
var remotePassword = ConfigurationManager.AppSettings["RemotePassword"];
var remoteDomain = ConfigurationManager.AppSettings["RemoteDomain"];
var safeTokenHandle = ImpersonationHelper.GetSafeTokenHandle(remoteUser, remotePassword, remoteDomain);
using (safeTokenHandle)
{
using (WindowsIdentity newId = new WindowsIdentity(safeTokenHandle.DangerousGetHandle()))
{
using (WindowsImpersonationContext impersonatedUser = newId.Impersonate())
{
// do stuff here the same as you would locally
}
}
}

C# File system on remote server in ActiveDirectory and Impersonation

This theme are not new. But I need help of some professional.
I am making a windows form application which will run on local system(not domain's computer). The application would creating folder and some files on Active Directory domain's shared folder.
I have read about Impersonation and have tried to make some thing like this: Impersonation by using LogonUser
Then I wrote the next code:
using System.Security.Principal;
using System.Runtime.InteropServices;
public partial class Form1 : Form
{
private enum LogonSessionType : uint
{
Interactive = 2,
Network,
Batch,
Service,
NetworkCleartext = 8,
NewCredentials
}
private enum LogonProvider : uint
{
Default = 0,
WinNT35,
WinNT40,
WinNT50
}
[DllImport("kernel32.dll", SetLastError = true)]
public static extern bool CloseHandle(IntPtr handle);
[DllImport("advapi32.dll", SetLastError = true)]
static extern bool LogonUser(
string principal,
string authority,
string password,
LogonSessionType logonType,
LogonProvider logonProvider,
out IntPtr token);
public Form1()
{
InitializeComponent();
}
protected void btnConnect_Click(object sender, EventArgs e)
{
IntPtr token = IntPtr.Zero;
WindowsImpersonationContext impersonateUser = null;
try
{
bool result = LogonUser("Administrator#mydomain.ru", "192.168.1.1", "SomeP#ssWorD",
LogonSessionType.Network, LogonProvider.Default, out token);
if(result)
{
WindowsIdentity id = new WindowsIdentity(token);
impersonateUser = id.Impersonate();
string showtext = string.Format("Identity: {0}", WindowsIdentity.GetCurrent().Name);
MessageBox.Show(showtext);
}
else
{
string showtext = string.Format("Identity: {0}", "Fail");
MessageBox.Show(showtext);
}
}
catch
{
}
finally
{
if(impersonateUser!=null)
impersonateUser.Undo();
if (token != IntPtr.Zero)
CloseHandle(token);
}
}
}
But bool result is always = false. What am I doing wrong?
i was wrong about understanding of LogonUser function. I was thinking that this function get remote token, but it generate.
Here is the right using:
bool result = LogonUser("Administrator", "mydomain.ru", "SomePa$$worD", LogonSessionType.NewCredentials, LogonProvider.Default, out safeTokenHandle);

Unable to find an entry point named 'LogonUser' in DLL 'advapi32.dll' Impersonation exception

I'm getting the following exception when going through some legacy impersonation logic:
Unable to find an entry point named 'LogonUser' in DLL 'advapi32.dll'
I understand that the error means that my app can't find the LogonUser method in the advapi32.dll.
The code looks something like this:
[DllImport("advapi32.dll", CharSet = CharSet.Auto, SetLastError = true, ExactSpelling = true)]
private static extern bool LogonUser(String lpszUsername, String lpszDomain, String lpszPassword, int dwLogonType, int dwLogonProvider, ref IntPtr phToken);
if(LogonUser(_username, _domainname, _password, LOGON32_LOGON_INTERACTIVE, LOGON32_PROVIDER_DEFAULT, ref _tokenHandle))
{
//do stuff...
}
Has anyone had a similar error - any suggestions on how to fix it or why it is happening? Is there a better way to do this besides using the advapi32.dll (its a .net 3.5 solution but there are lots of legacy classes)?
Maybe it has something to do with the "ExactSpelling = true"
This seems to work:
public enum LogonType : int
{
Interactive = 2,
Network = 3,
Batch = 4,
Service = 5,
Unlock = 7,
NetworkCleartText = 8,
NewCredentials = 9,
}
public enum LogonProvider : int
{
Default = 0,
}
public class Impersonation : IDisposable
{
#region Dll Imports
[DllImport("kernel32.dll")]
private static extern Boolean CloseHandle(IntPtr hObject);
[DllImport("advapi32.dll", CharSet = CharSet.Auto, SetLastError = true)]
private static extern bool LogonUser(string username, string domain,
string password, LogonType logonType,
LogonProvider logonProvider,
out IntPtr userToken);
[DllImport("advapi32.dll", CharSet = CharSet.Auto, SetLastError = true)]
private static extern bool DuplicateToken(IntPtr token, int impersonationLevel,
ref IntPtr duplication);
[DllImport("advapi32.dll", SetLastError = true)]
static extern bool ImpersonateLoggedOnUser(IntPtr userToken);
#endregion
#region Private members
private bool _disposed;
private WindowsImpersonationContext _impersonationContext;
#endregion
#region Constructors
public Impersonation(String username, String domain, String password)
{
IntPtr userToken = IntPtr.Zero;
IntPtr userTokenDuplication = IntPtr.Zero;
// Logon with user and get token.
bool loggedOn = LogonUser(username, domain, password,
LogonType.Interactive, LogonProvider.Default,
out userToken);
if (loggedOn)
{
try
{
// Create a duplication of the usertoken, this is a solution
// for the known bug that is published under KB article Q319615.
if (DuplicateToken(userToken, 2, ref userTokenDuplication))
{
// Create windows identity from the token and impersonate the user.
WindowsIdentity identity = new WindowsIdentity(userTokenDuplication);
_impersonationContext = identity.Impersonate();
}
else
{
// Token duplication failed!
// Use the default ctor overload
// that will use Mashal.GetLastWin32Error();
// to create the exceptions details.
throw new Exception("Could not copy token");
}
}
finally
{
// Close usertoken handle duplication when created.
if (!userTokenDuplication.Equals(IntPtr.Zero))
{
// Closes the handle of the user.
CloseHandle(userTokenDuplication);
userTokenDuplication = IntPtr.Zero;
}
// Close usertoken handle when created.
if (!userToken.Equals(IntPtr.Zero))
{
// Closes the handle of the user.
CloseHandle(userToken);
userToken = IntPtr.Zero;
}
}
}
else
{
throw new Exception("Login failed");
}
}
~Impersonation()
{
Dispose(false);
}
#endregion
#region Public methods
public void Revert()
{
if (_impersonationContext != null)
{
// Revert to previous user.
_impersonationContext.Undo();
_impersonationContext = null;
}
}
#endregion
#region IDisposable implementation.
public void Dispose()
{
Dispose(true);
GC.SuppressFinalize(this);
}
protected virtual void Dispose(bool disposing)
{
if (!_disposed)
{
Revert();
_disposed = true;
}
}
#endregion
}
Have you tried using the version of LogonUser's signature provided on pinvoke.net?

ASP.NET Development Server permissions and Network Resources

My ASP.NET 4.0 Web App is unable to access Network Printers, while debugging on VS 2010. It can access local printers. Seems like it may be a permissions issue. Since VS2010 Debugging runs on ASP.NET Development Server, it must be running under the account I used to log into Windows, right? Does that user need to be added as an Admin in that printers users? Is there any account that I can impersonate to get this working?
You are correct, debugging through Visual Studio means all of your code runs with the same rights as the user logged in to windows. On the server, you will need to setup impersonation and/or setup your Application Pool to run as a user who has access to print on these printers.
I recommend you setup a dedicated domain account (like domain\yourapp-impers-user) and either set the Application Pool to use that, or setup impersonation in your web.config. Then on the print server, you simply grant that user account the necessary permissions.
Here is an example of impersonation
using System;
using System.Collections.Generic;
using System.Web.Security;
using System.Security.Principal;
using System.Runtime.InteropServices;
using System.Linq;
using System.Web;
using System.IO;
public partial class Main : PageBase
{
public const int LOGON32_LOGON_INTERACTIVE = 2;
public const int LOGON32_PROVIDER_DEFAULT = 0;
WindowsImpersonationContext impersonationContext;
[DllImport("advapi32.dll")]
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)]
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);
protected void Page_Load(object sender, EventArgs e)
{
if (Page.IsPostBack == false)
{
if (impersonateValidUser("Username", "Domain", "Password"))
{
//Your code under a specific user here.
}
}
}
private bool impersonateValidUser(String userName, String domain, String password)
{
WindowsIdentity tempWindowsIdentity;
IntPtr token = IntPtr.Zero;
IntPtr tokenDuplicate = IntPtr.Zero;
if (RevertToSelf())
{
if (LogonUserA(userName, domain, password, LOGON32_LOGON_INTERACTIVE,
LOGON32_PROVIDER_DEFAULT, ref token) != 0)
{
if (DuplicateToken(token, 2, ref tokenDuplicate) != 0)
{
tempWindowsIdentity = new WindowsIdentity(tokenDuplicate);
impersonationContext = tempWindowsIdentity.Impersonate();
if (impersonationContext != null)
{
CloseHandle(token);
CloseHandle(tokenDuplicate);
return true;
}
}
}
}
if (token != IntPtr.Zero)
CloseHandle(token);
if (tokenDuplicate != IntPtr.Zero)
CloseHandle(tokenDuplicate);
return false;
}
private void undoImpersonation()
{
impersonationContext.Undo();
}
Good luck !
without knowing for sure, you can try to impersonate the Network Service, or of course your own domain account which should always work.

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