Re: VB.NET LDAP Class

From: Jon Delano (jd31068_at_hotmail.com)
Date: 07/30/04 

Date: Fri, 30 Jul 2004 13:43:52 GMT

Well slap someone for just trying to help out some.

I made no comments that it was the best option ... only that it worked for
me in what I was doing (I did use AuthenticationTypes.Secure in my code by
the way and I have added the dispose and set the objects to nothing.)

At the very least it might give someone a starting point if they are lost.

"Joe Kaplan (MVP - ADSI)" <joseph.e.kaplan@removethis.accenture.com> wrote
in message news:%23LMMvibdEHA.2384@TK2MSFTNGP09.phx.gbl...
> Actually, the code in that article is pretty bad and contains a number of
> flaws that in my opinion make it not worthy of emulation.
>
> Problems in the IsAuthenticated method include:
> - They don't use AuthenticationTypes.Secure, so password is sent in clear
> text over the network (!)
> - They don't properly call Dispose on the IDisposable objects, so memory
> leaks will occur, especially given the bugs in the Finalize method for
> DirectoryEntry in .NET 1.0 and 1.1
> - They make a bad assumption about the source the failure by catching the
> general Exception class instead of looking for the "bad credentials"
HRESULT
> on the COMException that should be thrown
> - They make some bad assumptions that won't necessarily work in a
> multi-domain forest about looking up the user's user name
>
> Problems in the GetGroups methods include:
> - MemberOf attribute includes non-security groups, does not included
nested
> group membership and does not include the primary group, so essentially
that
> isn't the correct list
> - Use the CN attribute for making a security decision instead of
> sAMAccountName even though CN may not be unique in the directory (only the
> current container)
> - Parse the DN with a naive check ",", even though DN's can contain ","
> escaped with \
> - Fail to clean up and catch proper exception types as above
>
> As you can see, I'm pretty grumpy about that sample code. Perhaps someday
> I'll post something better or it can be fixed. In the mean time, please
> don't use it.
>
> Joe K.
>
>
> "Raterus" <raterus@spam.org> wrote in message
> news:eRYH11adEHA.3212@TK2MSFTNGP12.phx.gbl...
> I hope you didn't spend too long converting this.. :-)
> http://support.microsoft.com/default.aspx?scid=kb;EN-US;326340
>
> "Jon Delano" <jd31068@hotmail.com> wrote in message
> news:94cOc.209721$Oq2.196851@attbi_s52...
> > Hello
> >
> > After some effort I was able to come up with this class (converted from
a
> C#
> > example on MS' web site).
> > Put this in a class in you vb.net web project and you should be able to
> > authenticate a user against active directory and also retrieve their
user
> > groups.
> >
> > You must replace the LDAP://yourdomain with the actual domain that you'd
> > like to authenticate against.
> >
> > Please do with this as you will (and use at your own risk):
> >
> > Imports System.DirectoryServices
> > Imports System.Runtime.InteropServices
> > Imports System.Globalization
> >
> > Public Class ADAuthenticate
> > Private _path As String
> > Private _filterAttribute As String
> > Private _UserFirstName As String
> > Private _UserLastName As String
> > Private _UserPath As String
> > Private _AuthenticationErrorString As String
> >
> > Public Function IsAuthenticated(ByVal UserName As String, ByVal
> Password
> > As String) As Boolean
> > ' authenticate the user and get some info about them
> > Dim entry As New DirectoryEntry("LDAP://yourdomain", UserName,
> > Password, System.DirectoryServices.AuthenticationTypes.Secure)
> > Dim ds As New DirectorySearcher(entry)
> > Dim myFilter As String = "(&(objectClass=user)(samaccountname="
+
> > UserName + "))"
> >
> > ds.Filter = myFilter
> > ds.PropertiesToLoad.Add("sn")
> > ds.PropertiesToLoad.Add("GivenName")
> >
> > Try
> > Dim sRslt As SearchResult = ds.FindOne
> > If sRslt Is Nothing Then
> > Return False
> > Else
> > _filterAttribute = UserName
> > Dim propName As String
> > Dim value As Object
> >
> > For Each propName In sRslt.Properties.PropertyNames
> > For Each value In sRslt.Properties(propName)
> > If propName = "sn" Then
> > _UserLastName = value
> > End If
> >
> > If propName = "givenname" Then
> > _UserFirstName = value
> > End If
> >
> > If propName = "adspath" Then
> > _UserPath = value
> > End If
> >
> > Next value
> > Next propName
> >
> > Return True
> > End If
> >
> > sRslt = Nothing
> > ds = Nothing
> >
> > Catch ex As Exception
> > _AuthenticationErrorString = ex.Message & "<br>" &
> ex.StackTrace
> > Return False
> > Finally
> > entry.Dispose()
> > entry = Nothing
> > ds.Dispose()
> > ds = Nothing
> > End Try
> >
> > End Function
> >
> > Public ReadOnly Property LdapAuthenticationErrorString() As String
> > Get
> > Return _AuthenticationErrorString
> > End Get
> > End Property
> >
> > Public ReadOnly Property LdapUserFirstName() As String
> > Get
> > Return _UserFirstName
> > End Get
> > End Property
> >
> > Public ReadOnly Property LdapUserLastName() As String
> > Get
> > Return _UserLastName
> > End Get
> > End Property
> >
> > Public Function GetUserGroups(ByVal UserName As String, ByVal
Password
> > As String) As String
> > ' get the groups the user belongs to
> > Dim entry As New DirectoryEntry("LDAP://yourdomain", UserName,
> > Password, System.DirectoryServices.AuthenticationTypes.Secure)
> > Dim search = New DirectorySearcher(entry)
> >
> > search.Filter = "(&(objectClass=user)(cn=" + _filterAttribute +
> "))"
> > search.PropertiesToLoad.Add("memberOf")
> >
> > Dim groupNames As New System.Text.StringBuilder()
> >
> > Try
> > Dim result As SearchResult = search.FindOne()
> > Dim propertyCount As Int32 =
> result.Properties("memberOf").Count
> > Dim dn As String
> > Dim equalsIndex As Int32, commaIndex As Int32
> > Dim propertyCounter As Int32
> >
> > For propertyCounter = 0 To propertyCount - 1
> > dn = result.Properties("memberOf")(propertyCounter)
> > equalsIndex = dn.IndexOf("=", 1)
> > commaIndex = dn.IndexOf(",", 1)
> > If (-1 = equalsIndex) Then
> > groupNames.Append(dn)
> > Else
> > groupNames.Append(dn.Substring((equalsIndex + 1),
> > (commaIndex - equalsIndex) - 1))
> > groupNames.Append("|")
> > End If
> >
> > Next propertyCounter
> >
> > Catch ex As Exception
> > Throw New Exception("Error obtaining group names. " +
> > ex.Message)
> > Finally
> > entry.Dispose()
> > entry = Nothing
> > search = Nothing
> > End Try
> >
> > Return groupNames.ToString()
> >
> > End Function
> > End Class
> >
> > Good luck
> > Jon
> >
> >
>
>

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