Accessing Network Resources

[raresm79]

Hi!

i'm trying to read a file using default share in c#. Is there a method to send the username/password to the remote machine that have the necessary rights to access the default share and read the file. I did this under VC++ with the WNetAddConnection() function.But i can't find anything like this in C#.

Please advice....
Thx...Rares

[Aleksej]

Hi,
As far as I know, there're only System.Net to provide socket interface. So for more complicated functions like WNetAddconnection() from <winsock.h> or <winsock2.h> you should use P/Invoke

[raresm79]

Thanks a lot for ur answer. I don't want to use only WNetAddConnection. I would like to know if there is a method in .Net that can give me access to a network resource by providing a username and password that have access to that resource.

Cheers

[stepi]

Hi there,
To answer your question i don't know a method that will do that for you.You will need to impersonate the user prior to accessing your network shared resources:

using System.Security.Principal;
using System.Runtime.InteropServices;
.....................
#region Impersonate

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);

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;
}
}
else
{

}
}
else
{

}
}
else
{

}
if(token!= IntPtr.Zero)
CloseHandle(token);
if(tokenDuplicate!=IntPtr.Zero)
CloseHandle(tokenDuplicate);
return false;
}

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

..................................
if(impersonateValidUser(USER_NAME, DOMAIN, PASSWORD))
{
//here you can have your code for reading your file
undoImpersonation();
}