How to determine all the groups a user belongs to

问题:

I have an application that uses ActiveDirecotry authorisation and it has been decided that it needs to support nested AD groups, e.g.:

MAIN_AD_GROUP
     |
     |-> SUB_GROUP
              | 
              |-> User

So, the user in not directly a member of MAIN_AD_GROUP. I'd like to be able to look for the user recursively, searching the groups nested in MAIN_AD_GROUP.

The main problem is that I'm using .NET 3.5 and there is a bug in System.DirectoryServices.AccountManagement in .NET 3.5 whereby the method UserPrincipal.IsMemberOf() will not work for groups with more than 1500 users. So I can't use UserPrincipal.IsMemberOf() and no, I can't switch to .NET 4 either.

I've worked around this last problem with the following function:

private bool IsMember(Principal userPrincipal, Principal groupPrincipal)
{
    using (var groups = userPrincipal.GetGroups())
    {
        var isMember = groups.Any(g => 
            g.DistinguishedName == groupPrincipal.DistinguishedName);
        return isMember;
    }
}

But userPrincipal.GetGroups() only returns the groups of which the user is a direct member.

How can I get this to work with nested groups?

回答1:

Workaround #1

This bug is reported here at Microsoft Connect along with the following code that works around this issue by manually iterating through the PrincipalSearchResult<Principal> returned objects, catching this exception, and continuing on:

PrincipalSearchResult<Principal> groups = user.GetAuthorizationGroups();
var iterGroup = groups.GetEnumerator();
using (iterGroup)
{
    while (iterGroup.MoveNext())
    {
        try
        {
            Principal p = iterGroup.Current;
            Console.WriteLine(p.Name);
        }
        catch (NoMatchingPrincipalException pex)
        {
            continue;
        }
    }
}

Workaround #2

Another workaround found here avoids the AccountManagement class, and uses the System.DirectoryServices API instead:

using System;  
using System.Collections.Generic;  
using System.Linq;  
using System.Text;  
using System.DirectoryServices;  

namespace GetGroupsForADUser  
{  
    class Program  
    {  
        static void Main(string[] args)  
        {  
            String username = "Gabriel";  

            List<string> userNestedMembership = new List<string>();  

            DirectoryEntry domainConnection = new DirectoryEntry(); // Use this to query the default domain
            //DirectoryEntry domainConnection = new DirectoryEntry("LDAP://example.com", "username", "password"); // Use this to query a remote domain

            DirectorySearcher samSearcher = new DirectorySearcher();  

            samSearcher.SearchRoot = domainConnection;  
            samSearcher.Filter = "(samAccountName=" + username + ")";  
            samSearcher.PropertiesToLoad.Add("displayName");  

            SearchResult samResult = samSearcher.FindOne();  

            if (samResult != null)  
            {  
                DirectoryEntry theUser = samResult.GetDirectoryEntry();  
                theUser.RefreshCache(new string[] { "tokenGroups" });  

                foreach (byte[] resultBytes in theUser.Properties["tokenGroups"])  
                {  
                    System.Security.Principal.SecurityIdentifier mySID = new System.Security.Principal.SecurityIdentifier(resultBytes, 0);  

                    DirectorySearcher sidSearcher = new DirectorySearcher();  

                    sidSearcher.SearchRoot = domainConnection;  
                    sidSearcher.Filter = "(objectSid=" + mySID.Value + ")";  
                    sidSearcher.PropertiesToLoad.Add("distinguishedName");  

                    SearchResult sidResult = sidSearcher.FindOne();  

                    if (sidResult != null)  
                    {  
                        userNestedMembership.Add((string)sidResult.Properties["distinguishedName"][0]);  
                    }  
                }  

                foreach (string myEntry in userNestedMembership)  
                {  
                    Console.WriteLine(myEntry);  
                }  

            }  
            else 
            {  
                Console.WriteLine("The user doesn't exist");  
            }  

            Console.ReadKey();  

        }  
    }  
}  

回答2:

Use UserPrincipal.GetAuthorizationGroups() instead - from its MSDN docs:

This method searches all groups recursively and returns the groups in which the user is a member. The returned set may also include additional groups that system would consider the user a member of for authorization purposes.

The groups that are returned by this method may include groups from a different scope and store than the principal. For example, if the principal is an AD DS object that has a DN of "CN=SpecialGroups,DC=Fabrikam,DC=com, the returned set can contain groups that belong to the "CN=NormalGroups,DC=Fabrikam,DC=com.

回答3:

I know this is an old thread, but it's the top result on Google, so in case this helps anyone, here's what I came up with that uses the AccountManagement stuff, but makes this particular query much easier.

public static class AccountManagementExtensions
{
    public static bool IsNestedMemberOf(this Principal principal, GroupPrincipal group)
    {
        // LDAP Query for memberOf Nested 
        var filter = String.Format("(&(sAMAccountName={0})(memberOf:1.2.840.113556.1.4.1941:={1}))",
                principal.SamAccountName,
                group.DistinguishedName
            );

        var searcher = new DirectorySearcher(filter);

        var result = searcher.FindOne();

        return result != null;
    }
}

回答4:

The efficient way is to do a single AD query by having the right DirectorySearcher filter for e.g.

public bool CheckMemberShip(string userName)
    {

        bool membership = false;
        string connection = "LDAP://"+YOURDOMAIN;
        DirectoryEntry entry = new DirectoryEntry(connection);
        DirectorySearcher mySearcher = new DirectorySearcher(entry);
        mySearcher.Filter = "(&(objectClass=user)(memberOf:1.2.840.113556.1.4.1941:=cn=GROUPNAME,OU=Groups,OU=ABC,OU=ABC,OU=IND,DC=ad,DC=COMPANY,DC=com)(|(sAMAccountName=" + userName + ")))";
        SearchResult result = mySearcher.FindOne();

        // No search result, hence no membership
        if (result == null)
        {
            membership = false;
        }

        entry.Close();
        entry.Dispose();
        mySearcher.Dispose();

        membership = true;
        return membership;
    }

You need to replace YOURDOMAIN and GROUPNAME with right values from your AD.

Source : How to Recursively Get the Group Membership of a User in Active Directory using .NET/C# and LDAP (without just 2 hits to Active Directory)

Need to include using System.DirectoryServices;