Is there a simple out of the box way to impersonate a user in .NET?
So far I\'ve been using this class from code project for all my impersonation requirements.
Here's my vb.net port of Matt Johnson's answer. I added an enum for the logon types. LOGON32_LOGON_INTERACTIVE
was the first enum value that worked for sql server. My connection string was just trusted. No user name / password in the connection string.
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Public Class Impersonation
Implements IDisposable
Public Enum LogonTypes
'''
''' 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.
'''
LOGON32_LOGON_INTERACTIVE = 2
'''
''' This logon type is intended for high performance servers to authenticate plaintext passwords.
''' The LogonUser function does not cache credentials for this logon type.
'''
LOGON32_LOGON_NETWORK = 3
'''
''' 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.
'''
LOGON32_LOGON_BATCH = 4
'''
''' Indicates a service-type logon. The account provided must have the service privilege enabled.
'''
LOGON32_LOGON_SERVICE = 5
'''
''' 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.
'''
LOGON32_LOGON_UNLOCK = 7
'''
''' 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.
'''
LOGON32_LOGON_NETWORK_CLEARTEXT = 8
'''
''' 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.
'''
LOGON32_LOGON_NEW_CREDENTIALS = 9
End Enum
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Private Shared Function LogonUser(lpszUsername As [String], lpszDomain As [String], lpszPassword As [String], dwLogonType As Integer, dwLogonProvider As Integer, ByRef phToken As SafeTokenHandle) As Boolean
End Function
Public Sub New(Domain As String, UserName As String, Password As String, Optional LogonType As LogonTypes = LogonTypes.LOGON32_LOGON_INTERACTIVE)
Dim ok = LogonUser(UserName, Domain, Password, LogonType, 0, _SafeTokenHandle)
If Not ok Then
Dim errorCode = Marshal.GetLastWin32Error()
Throw New ApplicationException(String.Format("Could not impersonate the elevated user. LogonUser returned error code {0}.", errorCode))
End If
WindowsImpersonationContext = WindowsIdentity.Impersonate(_SafeTokenHandle.DangerousGetHandle())
End Sub
Private ReadOnly _SafeTokenHandle As New SafeTokenHandle
Private ReadOnly WindowsImpersonationContext As WindowsImpersonationContext
Public Sub Dispose() Implements System.IDisposable.Dispose
Me.WindowsImpersonationContext.Dispose()
Me._SafeTokenHandle.Dispose()
End Sub
Public NotInheritable Class SafeTokenHandle
Inherits SafeHandleZeroOrMinusOneIsInvalid
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Private Shared Function CloseHandle(handle As IntPtr) As Boolean
End Function
Public Sub New()
MyBase.New(True)
End Sub
Protected Overrides Function ReleaseHandle() As Boolean
Return CloseHandle(handle)
End Function
End Class
End Class
You need to Use with a Using
statement to contain some code to run impersonated.