Accessing Password Protected Network Drives in Windows in C#?

Solution 1:

This question got me to where I needed to be pretty quickly in the same case.

Here's how I adapted the code:

using System;
using System.Runtime.InteropServices;

/// <summary>
/// Implements P/Invoke Interop calls to the operating system.
/// </summary>
internal static class NativeMethods
{
    /// <summary>
    /// The type of logon operation to perform.
    /// </summary>
    internal enum LogonType : int
    {
        /// <summary>
        /// This logon type is intended for users who will be interactively
        /// using the computer, such as a user being logged on by a
        /// terminal server, remote shell, or similar process.
        /// This logon type has the additional expense of caching logon
        /// information for disconnected operations; therefore, it is
        /// inappropriate for some client/server applications, such as a
        /// mail server.
        /// </summary>
        Interactive = 2,

        /// <summary>
        /// This logon type is intended for high performance servers to
        /// authenticate plaintext passwords.
        /// The LogonUser function does not cache credentials for this
        /// logon type.
        /// </summary>
        Network = 3,

        /// <summary>
        /// This logon type is intended for batch servers, where processes
        /// may be executing on behalf of a user without their direct
        /// intervention.  This type is also for higher performance servers
        /// that process many plaintext authentication attempts at a time,
        /// such as mail or Web servers.
        /// The LogonUser function does not cache credentials for this
        /// logon type.
        /// </summary>
        Batch = 4,

        /// <summary>
        /// Indicates a service-type logon.  The account provided must have
        /// the service privilege enabled.
        /// </summary>
        Service = 5,

        /// <summary>
        /// This logon type is for GINA DLLs that log on users who will be
        /// interactively using the computer.
        /// This logon type can generate a unique audit record that shows
        /// when the workstation was unlocked.
        /// </summary>
        Unlock = 7,

        /// <summary>
        /// This logon type preserves the name and password in the
        /// authentication package, which allows the server to make
        /// connections to other network servers while impersonating the
        /// client.  A server can accept plaintext credentials from a
        /// client, call LogonUser, verify that the user can access the
        /// system across the network, and still communicate with other
        /// servers.
        /// NOTE: Windows NT:  This value is not supported.
        /// </summary>
        NetworkCleartext = 8,

        /// <summary>
        /// This logon type allows the caller to clone its current token
        /// and specify new credentials for outbound connections.  The new
        /// logon session has the same local identifier but uses different
        /// credentials for other network connections.
        /// NOTE: This logon type is supported only by the
        /// LOGON32_PROVIDER_WINNT50 logon provider.
        /// NOTE: Windows NT:  This value is not supported.
        /// </summary>
        NewCredentials = 9
    }

    /// <summary>
    /// Specifies the logon provider.
    /// </summary>
    internal enum LogonProvider : int
    {
        /// <summary>
        /// Use the standard logon provider for the system.
        /// The default security provider is negotiate, unless you pass
        /// NULL for the domain name and the user name is not in UPN format.
        /// In this case, the default provider is NTLM.
        /// NOTE: Windows 2000/NT:   The default security provider is NTLM.
        /// </summary>
        Default = 0,

        /// <summary>
        /// Use this provider if you'll be authenticating against a Windows
        /// NT 3.51 domain controller (uses the NT 3.51 logon provider).
        /// </summary>
        WinNT35 = 1,

        /// <summary>
        /// Use the NTLM logon provider.
        /// </summary>
        WinNT40 = 2,

        /// <summary>
        /// Use the negotiate logon provider.
        /// </summary>
        WinNT50 = 3
    }

    /// <summary>
    /// The type of logon operation to perform.
    /// </summary>
    internal enum SecurityImpersonationLevel : int
    {
        /// <summary>
        /// The server process cannot obtain identification information
        /// about the client, and it cannot impersonate the client.  It is
        /// defined with no value given, and thus, by ANSI C rules,
        /// defaults to a value of zero.
        /// </summary>
        Anonymous = 0,

        /// <summary>
        /// The server process can obtain information about the client,
        /// such as security identifiers and privileges, but it cannot
        /// impersonate the client.  This is useful for servers that export
        /// their own objects, for example, database products that export
        /// tables and views.  Using the retrieved client-security
        /// information, the server can make access-validation decisions
        /// without being able to use other services that are using the
        /// client's security context.
        /// </summary>
        Identification = 1,

        /// <summary>
        /// The server process can impersonate the client's security
        /// context on its local system.  The server cannot impersonate the
        /// client on remote systems.
        /// </summary>
        Impersonation = 2,

        /// <summary>
        /// The server process can impersonate the client's security
        /// context on remote systems.
        /// NOTE: Windows NT:  This impersonation level is not supported.
        /// </summary>
        Delegation = 3
    }

    /// <summary>
    /// Logs on the user.
    /// </summary>
    /// <param name="userName">Name of the user.</param>
    /// <param name="domain">The domain.</param>
    /// <param name="password">The password.</param>
    /// <param name="logonType">Type of the logon.</param>
    /// <param name="logonProvider">The logon provider.</param>
    /// <param name="token">The token.</param>
    /// <returns>True if the function succeeds, false if the function fails.
    /// To get extended error information, call GetLastError.</returns>
    [DllImport("advapi32.dll", CharSet = CharSet.Unicode, SetLastError = true)]
    [return: MarshalAs(UnmanagedType.Bool)]
    internal static extern bool LogonUser(
        string userName,
        string domain,
        string password,
        LogonType logonType,
        LogonProvider logonProvider,
        out IntPtr token);

    /// <summary>
    /// Duplicates the token.
    /// </summary>
    /// <param name="existingTokenHandle">The existing token
    /// handle.</param>
    /// <param name="securityImpersonationLevel">The security impersonation
    /// level.</param>
    /// <param name="duplicateTokenHandle">The duplicate token
    /// handle.</param>
    /// <returns>True if the function succeeds, false if the function fails.
    /// To get extended error information, call GetLastError.</returns>
    [DllImport("advapi32.dll", CharSet = CharSet.Unicode, SetLastError = true)]
    [return: MarshalAs(UnmanagedType.Bool)]
    internal static extern bool DuplicateToken(
        IntPtr existingTokenHandle,
        SecurityImpersonationLevel securityImpersonationLevel,
        out IntPtr duplicateTokenHandle);

    /// <summary>
    /// Closes the handle.
    /// </summary>
    /// <param name="handle">The handle.</param>
    /// <returns>True if the function succeeds, false if the function fails.
    /// To get extended error information, call GetLastError.</returns>
    [DllImport("kernel32.dll", CharSet = CharSet.Unicode, SetLastError = true)]
    [return: MarshalAs(UnmanagedType.Bool)]
    internal static extern bool CloseHandle(IntPtr handle);
}

followed by

IntPtr token;

if (!NativeMethods.LogonUser(
    this.userName,
    this.domain,
    this.password,
    NativeMethods.LogonType.NewCredentials,
    NativeMethods.LogonProvider.Default,
    out token))
{
    throw new Win32Exception();
}

try
{
    IntPtr tokenDuplicate;

    if (!NativeMethods.DuplicateToken(
        token,
        NativeMethods.SecurityImpersonationLevel.Impersonation,
        out tokenDuplicate))
    {
        throw new Win32Exception();
    }

    try
    {
        using (WindowsImpersonationContext impersonationContext =
            new WindowsIdentity(tokenDuplicate).Impersonate())
        {
            // Do stuff with your share here.

            impersonationContext.Undo();
            return;
        }
    }
    finally
    {
        if (tokenDuplicate != IntPtr.Zero)
        {
            if (!NativeMethods.CloseHandle(tokenDuplicate))
            {
                // Uncomment if you need to know this case.
                ////throw new Win32Exception();
            }
        }
    }
}
finally
{
    if (token != IntPtr.Zero)
    {
        if (!NativeMethods.CloseHandle(token))
        {
            // Uncomment if you need to know this case.
            ////throw new Win32Exception();
        }
    }
}