I've been searching a lot on the web for Active Directories and windows authentications. I've succeded on getting the User information from the Domain AD but I had to pass the User name AND PASSWORD. So to put you into my context :
I have a Domain where I've set my users. Each Users will be connecting to the domain with their given credentials. So they will log into their PC and when they open a VS 2013 C# application it will check if the users Exists on the Domain if he does then return the AD information if the users doesn't exist then show a Login Page to enter the Credentials. Since I can have external users connecting to my Domain etc ...
right now I cannot access the AD with the user's windows authentication it gives me a Unkown error on the Search.FindOne();
public static void GetActiveDirectoryUser(string UserName)
{
try
{
// Create LDAP connetion object
DirectoryEntry ldapConnection = CreateDirectoryEntry();
// Create Search object which operates on LDAP connection object
// and set search object to only find the user specified
DirectorySearcher search = new DirectorySearcher(ldapConnection);
// Create results objects from search object
SearchResult result = search.FindOne();
if (result != null)
{
// User exists, cycle through LDAP fields (cn, telephonenumber, etc.)
ResultPropertyCollection fields = result.Properties;
foreach (string ldapField in fields.PropertyNames)
{
// Cycle through objects in each field e.g group membership
foreach (Object objCollection in fields[ldapField])
{
Console.WriteLine(String.Format("{0, -20} : {1}", ldapField, objCollection.ToString()));
}
}
}
}
catch (Exception e)
{
Console.WriteLine("Exception Caught:\n\n" + e.ToString());
}
}
static DirectoryEntry CreateDirectoryEntry()
{
string pathDomainName = "WinNT://MyDomain/Fred,Person";
DirectoryEntry ldapConnection = new DirectoryEntry(pathDomainName);
return ldapConnection;
}
This is the error I'm getting
System.Runtime.InteropServices.COMException (0x80005000): Unknown error (0x80005000)
at System.DirectoryServices.DirectoryEntry.Bind(Boolean throwIfFail)
at System.DirectoryServices.DirectoryEntry.Bind()
at System.DirectoryServices.DirectoryEntry.get_AdsObject()
at System.DirectoryServices.DirectorySearcher.FindAll(Boolean findMoreThanOne)
at System.DirectoryServices.DirectorySearcher.FindOne()
but when I use this string
string pathDomainName = "LDAP://MyDomain";
DirectoryEntry directoryEntry = new DirectoryEntry(pathDomainName, "Fred", "f12345!");
it works, it returns me all the AD for the user, but I've already logged in with the windows authentication, why would I pass the credentials again ? I just need to know that if the user exists on the domain that's it
Thanks
If you're on .NET 3.5 and up, you should check out the System.DirectoryServices.AccountManagement (S.DS.AM) namespace. Read all about it here:
Managing Directory Security Principals in the .NET Framework 3.5
MSDN docs on System.DirectoryServices.AccountManagement
Basically, you can define a domain context and easily find users and/or groups in AD:
// set up domain context
using (PrincipalContext ctx = new PrincipalContext(ContextType.Domain))
{
// find a user
UserPrincipal user = UserPrincipal.FindByIdentity(ctx, "SomeUserName");
if(user != null)
{
// do something here....
}
// or alternatively: get the currently logged in user
UserPrincipal current = UserPrincipal.Current;
.....
}
The new S.DS.AM makes it really easy to play around with users and groups in AD!
Research:
Similar Issue with workaround, but not actual solution to existing problem
Similar issue pointing to Microsoft End Point update as culprit
The above links are the most suited to my problem, I have also viewed every similar question listed by Stack Overflow upon creating this post, and only the above referenced questions fit my issue.
Background:
I have been using UserPrincipal.GetAuthorizationGroups for permissions for specific page access running IIS 7.5 on Server 2008 R2 in a C#.NET 4.0 web forms site for 2 and a half years. On May 15 2013 we removed a primary Domain controller running Server 2008 (not r2) and replaced it with a Server 2012 Domain Controller. The next day we started receiving the exception listed below.
I use Principal Context for Forms Authentication. The username/pass handshake succeeds and the auth cookie is properly set, but the subsequent Principal Context call that also calls UserPrincipal.GetAuthorizationGroups fails intermittently. We've resolved a few BPA issues that appeared in the Server 2012 Domain Controller but this has yet to resolve the issue. I also instituted a cron that runs on two separate servers. The two servers will fail at Group SID resolution at different times though they are running the same code base. (A dev environment and production environment).
The issue resolves itself temporarily upon web server reboot, and also on the dev server it will resolve itself after 12 hours of not functioning. The production server will usually stop functioning properly until a reboot without resolving itself.
At this point I am trying to refine the cron targeting specific Domain Controllers in the network as well as the new DC and using the standard LDAP query that is currently failing to yield more targeted exception times. Thus far we've found on one web server that there is no pattern to the days at which it fails, but it will recover within roughly 12 hours. The latest results show Group SID resolution failure between 8AM-8PM then it recovers, several days later it will fail at 8pm and recover at 8am then run fine for another 12 hours and fail again. We are hoping to see if it is just a specific server communication issue or to see if it is the entire set of Domain Controllers.
Exception:
Exception information:
Exception type: PrincipalOperationException
Exception message: An error (1301) occurred while enumerating the groups.
The group's SID could not be resolved.
at System.DirectoryServices.AccountManagement.SidList.TranslateSids(String target, IntPtr[] pSids)
at System.DirectoryServices.AccountManagement.SidList..ctor(SID_AND_ATTR[] sidAndAttr)
at System.DirectoryServices.AccountManagement.AuthZSet..ctor(Byte[] userSid, NetCred credentials, ContextOptions contextOptions, String flatUserAuthority, StoreCtx userStoreCtx, Object userCtxBase)
at System.DirectoryServices.AccountManagement.ADStoreCtx.GetGroupsMemberOfAZ(Principal p)
at System.DirectoryServices.AccountManagement.UserPrincipal.GetAuthorizationGroups()
Question:
Given the above information, does anyone have any idea why decommissioning the Windows Server 2008 (not r2) and implementing a new Server 2012 DC would cause UserPrincipal.GetAuthorizationGroups to fail with the 1301 SID resolution error?
Ideas on eliminating possible causes would also be appreciated.
Disclaimer:
This is my first post to Stack Overflow, I often research here but have not joined in discussions until now. Forgive me if I should have posted elsewhere and feel free to point out better steps before posting.
UPDATE 13-JUN-2013:
On the 12th of June I addressed the possibility of items not disposed causing the issue.
The time frame has been too short to determine if the adjusted code has fixed the issue, but I will continue to update as we work towards a resolution such that maybe with any luck someone here can lend a hand.
Original Code
public bool isGroupMember(string userName, ArrayList groupList)
{
bool valid = false;
PrincipalContext ctx = new PrincipalContext(ContextType.Domain, domain_server + ".domain.org:636", null, ContextOptions.Negotiate | ContextOptions.SecureSocketLayer);
// find the user in the identity store
UserPrincipal user =
UserPrincipal.FindByIdentity(
ctx,
userName);
// get the groups for the user principal and
// store the results in a PrincipalSearchResult object
PrincipalSearchResult<Principal> groups =
user.GetAuthorizationGroups();
// display the names of the groups to which the
// user belongs
foreach (Principal group in groups)
{
foreach (string groupName in groupList)
{
if (group.ToString() == groupName)
{
valid = true;
}
}
}
return valid;
}
Updated Code
public bool isGroupMember(string userName, ArrayList groupList, string domain_server)
{
bool valid = false;
try
{
using (PrincipalContext ctx = new PrincipalContext(ContextType.Domain, domain_server + ".domain.org:636", null, ContextOptions.Negotiate | ContextOptions.SecureSocketLayer))
{
// find the user in the identity store
UserPrincipal user =
UserPrincipal.FindByIdentity(
ctx,
userName);
try
{
// get the groups for the user principal and
// store the results in a PrincipalSearchResult object
using (PrincipalSearchResult<Principal> groups = user.GetAuthorizationGroups())
{
// display the names of the groups to which the
// user belongs
foreach (Principal group in groups)
{
foreach (string groupName in groupList)
{
if (group.ToString() == groupName)
{
valid = true;
}
}
group.Dispose();
}
}//end using-2
}
catch
{
log_gen("arbitrary info");
return false;
}
}//end using-1
}
catch
{
log_gen("arbitrary info");
return false;
}
return valid;
}
I have just run into this same issue and the info I have managed to track down may be helpful; as above we have seen this problem where the domain controller is running Server 2012 - firstly with a customer deployment and then replicated on our own network.
After some experimentation we found that our code would run fine on Server 2012, but hit the 1301 error code when the client system was running Server 2008. The key information about what was happening was found here:
MS blog translated from German
The hotfix referred to in the link below has fixed the problem on our test system
SID S-1-18-1 and SID S-1-18-2 can't be mapped
Hope this is helpful for someone! As many have noted this method call seems rather fragile and we will probably look at implementing some alternative approach before we hit other issues.
Gary
Here's my solution. It seems to work consistently well. Because the problem happens when iterating over the collection, I use a different approach when iterating in order to handle the exception without blocking the actual iterating:
private string[] GetUserRoles(string Username)
{
List<string> roles = new List<string>();
try
{
string domain = Username.Contains("\\") ? Username.Substring(0, Username.IndexOf("\\")) : string.Empty;
string username = Username.Contains("\\") ? Username.Substring(Username.LastIndexOf("\\") + 1) : Username;
if (!string.IsNullOrEmpty(domain) && !string.IsNullOrEmpty(username))
{
PrincipalContext principalContext = new PrincipalContext(ContextType.Domain, domain);
UserPrincipal user = UserPrincipal.FindByIdentity(principalContext, username);
if (user != null)
{
PrincipalSearchResult<Principal> groups = user.GetAuthorizationGroups();
int count = groups.Count();
for (int i = 0; i < count; i++)
{
IEnumerable<Principal> principalCollection = groups.Skip(i).Take(1);
Principal principal = null;
try
{
principal = principalCollection.FirstOrDefault();
}
catch (Exception e)
{
//Error handling...
//Known exception - sometimes AD can't query a particular group, requires server hotfix?
//http://support.microsoft.com/kb/2830145
}
if (principal!=null && principal is GroupPrincipal)
{
GroupPrincipal groupPrincipal = (GroupPrincipal)principal;
if (groupPrincipal != null && !string.IsNullOrEmpty(groupPrincipal.Name))
{
roles.Add(groupPrincipal.Name.Trim());
}
}
}
}
}
}
catch (Exception e)
{
//Error handling...
}
return roles.ToArray();
}
We experienced this issue when our infrastructure team brought a 2012 Domain Controller online. We also had pre-2012 DCs in place and so we experienced the issue intermittently. We came up with a fix which I wanted to share - it has 2 parts.
First of all, install the hotfix mentioned by Gary Hill. This will resolve the following issue:
An error (1301) occurred while enumerating the groups. The group's SID could not be resolved.
We thought we were home free after installing this hotfix. However, after it was installed we got a different intermittent error. Certain groups that we were interrogating had a null sAMAccountName property. The actual property was populated in Active Directory but it was incorrectly being returned with a null value by the API. I presume this is a bug somewhere in the Active Directory API but I don't know any more than that.
Fortunately we were able to work around the issue by switching to use the group Name property instead of the sAMAccountName property. This worked for us. I believe, that sAMAccountName is effectively deprecated and exists only for backwards compatibility reasons. That being the case it seemed a reasonable change to make.
I enclose a cut down version of our GetRolesForUser code to demonstrate the change in place.
using (var context = new PrincipalContext(ContextType.Domain, _domainName))
{
try
{
var p = UserPrincipal.FindByIdentity(context, IdentityType.SamAccountName, username);
if (p == null) throw new NullReferenceException(string.Format("UserPrincipal.FindByIdentity returned null for user: {0}, this can indicate a problem with one or more of the AD controllers", username));
var groups = p.GetAuthorizationGroups();
var domain = username.Substring(0, username.IndexOf(#"\", StringComparison.InvariantCultureIgnoreCase)).ToLower();
foreach (GroupPrincipal group in groups)
{
if (!string.IsNullOrEmpty(group.Name))
{
var domainGroup = domain + #"\" + group.Name.ToLower();
if (_groupsToUse.Any(x => x.Equals(domainGroup, StringComparison.InvariantCultureIgnoreCase)))
{
// Go through each application role defined and check if the AD domain group is part of it
foreach (string role in roleKeys)
{
string[] roleMembers = new [] { "role1", "role2" };
foreach (string member in roleMembers)
{
// Check if the domain group is part of the role
if (member.ToLower().Contains(domainGroup))
{
// Cache the Application Role (NOT the AD role)
results.Add(role);
}
}
}
}
}
group.Dispose();
}
}
catch (Exception ex)
{
throw new ProviderException("Unable to query Active Directory.", ex);
}
}
Hope that helps.
I experienced error code 1301 with UserPrincipal.GetAuthorizationGroups while using a brand new virtual development domain which contained 2 workstations and 50 users/groups (many of which are the built in ones). We were running Windows Server 2012 R2 Essentials with two Windows 8.1 Enterprise workstations joined to the domain.
I was able to recursively obtain a list of a user's group membership using the following code:
class ADGroupSearch
{
List<String> groupNames;
public ADGroupSearch()
{
this.groupNames = new List<String>();
}
public List<String> GetGroups()
{
return this.groupNames;
}
public void AddGroupName(String groupName)
{
this.groupNames.Add(groupName);
}
public List<String> GetListOfGroupsRecursively(String samAcctName)
{
PrincipalContext ctx = new PrincipalContext(ContextType.Domain, System.Environment.UserDomainName);
Principal principal = Principal.FindByIdentity(ctx, IdentityType.SamAccountName, samAcctName);
if (principal == null)
{
return GetGroups();
}
else
{
PrincipalSearchResult<Principal> searchResults = principal.GetGroups();
if (searchResults != null)
{
foreach (GroupPrincipal sr in searchResults)
{
if (!this.groupNames.Contains(sr.Name))
{
AddGroupName(sr.Name);
}
Principal p = Principal.FindByIdentity(ctx, IdentityType.SamAccountName, sr.SamAccountName);
try
{
GetMembersForGroup(p);
}
catch (Exception ex)
{
//ignore errors and continue
}
}
}
return GetGroups();
}
}
private void GetMembersForGroup(Principal group)
{
if (group != null && typeof(GroupPrincipal) == group.GetType())
{
GetListOfGroupsRecursively(group.SamAccountName);
}
}
private bool IsGroup(Principal principal)
{
return principal.StructuralObjectClass.ToLower().Equals("group");
}
}
I'm in an environment with multiple domain forests and trusts. I have pretty much this exact same code running on a web site form used to perform user security group lookups across the different domains.
I get this exact error in one of the very large domains where group membership can include 50+ different groups. It works fine in other domains forests.
In my research I found a thread that looks unrelated, but actually has the same stack trace. It is for a remote application running on SBS. The thread mentions that the error is caused by unresolvable SIDS in a group. I believe these would be what are known as "tombstoned" SIDS in active directory. See the thread here.
The thread suggests that finding the tombstoned enteries and removing them from the groups solves the problem. Is it possible the error you are receiving is because SIDS are getting tombstoned every 12 hours by a separate unrelated process? Ultimately, I believe this is a bug in the framework, and that the method should not crash because of tombstoned/unresolvable SIDS.
Good luck!
If anyone is interested this is a VB.NET version of the same code.
Few things you have to do before this code can work
1) You have to reference the assembly System.DirectoryServices
2) Make sure to pass "theusername" variable without the domain, so if your domain is "GIS" and your username is "Hussein" Windows generally authenticate you as GIS\Hussein. So you have to send in just purely the username "Hussein". I worked out the case sensitive stuff.
3) The method GetGroupsNew takes a username and returns a list of groups
4) The method isMemberofnew takes a username and a group and verifies that this user is part of that group or not, this is the one I was interested in.
Private Function getGroupsNew(theusername As String) As List(Of String)
Dim lstGroups As New List(Of String)
Try
Dim allDomains = Forest.GetCurrentForest().Domains.Cast(Of Domain)()
Dim allSearcher = allDomains.[Select](Function(domain)
Dim searcher As New DirectorySearcher(New DirectoryEntry("LDAP://" + domain.Name))
searcher.Filter = [String].Format("(&(&(objectCategory=person)(objectClass=user)(userPrincipalName=*{0}*)))", theusername)
Return searcher
End Function)
Dim directoryEntriesFound = allSearcher.SelectMany(Function(searcher) searcher.FindAll().Cast(Of SearchResult)().[Select](Function(result) result.GetDirectoryEntry()))
Dim memberOf = directoryEntriesFound.[Select](Function(entry)
Using entry
Return New With { _
Key .Name = entry.Name, _
Key .GroupName = DirectCast(entry.Properties("MemberOf").Value, Object()).[Select](Function(obj) obj.ToString()) _
}
End Using
End Function)
For Each user As Object In memberOf
For Each groupName As Object In user.GroupName
lstGroups.Add(groupName)
Next
Next
Return lstGroups
Catch ex As Exception
Throw
End Try
End Function
Private Function isMemberofGroupNew(theusername As String, thegroupname As String) As Boolean
Try
Dim lstGroups As List(Of String) = getGroupsNew(theusername)
For Each sGroup In lstGroups
If sGroup.ToLower.Contains(thegroupname.ToLower) Then Return True
Next
Return False
Catch ex As Exception
Throw
End Try
End Function
we had a similar issue after upgrading the domain controller to 2012. Suddenly my call to user.GetAuthorizationGroups() started failing; I was getting the same exception you were (error 1301). So, I changed it to user.GetGroups(). That worked for a little while, then started failing intermittently on "bad username or password". My latest workaround appears to fix it, for the moment at least. Instead of calling either of those, after constructing the user object, I also construct a group object, one for each group I want to see if the user is a member of. ie, "user.IsMemberOf(group)". That seems to work.
try
{
using (HostingEnvironment.Impersonate())
{
using (var principalContext = new PrincipalContext(ContextType.Domain, "MYDOMAIN"))
{
using (var user = UserPrincipal.FindByIdentity(principalContext, userName))
{
if (user == null)
{
Log.Debug("UserPrincipal.FindByIdentity failed for userName = " + userName + ", thus not authorized!");
isAuthorized = false;
}
if (isAuthorized)
{
firstName = user.GivenName;
lastName = user.Surname;
// so this code started failing:
// var groups = user.GetGroups();
// adGroups.AddRange(from #group in groups where
// #group.Name.ToUpper().Contains("MYSEARCHSTRING") select #group.Name);
// so the following workaround, which calls, instead,
// "user.IsMemberOf(group)",
// appears to work (for now at least). Will monitor for issues.
// test membership in SuperUsers
const string superUsersGroupName = "MyApp-SuperUsers";
using (var superUsers = GroupPrincipal.FindByIdentity(principalContext, superUsersGroupName))
{
if (superUsers != null && user.IsMemberOf(superUsers))
// add to the list of groups this user is a member of
// then do something with it later
adGroups.Add(superUsersGroupName);
}
I had same exception. If someone don't wanna used "LDAP", use this code. Cause I'm had nested groups, I'm used GetMembers(true) and it's little bit longer in time than GetMembers().
https://stackoverflow.com/a/27548271/1857271
or download fix from here: http://support.microsoft.com/kb/2830145
Facing the same problem enumerating authorization groups and the patches noted in the answer did not apply to our web server.
Manually enumerating and ignoring the trouble causing groups is working well, however:
private static bool UserIsMember(string usr, string grp)
{
usr = usr.ToLower();
grp = grp.ToLower();
using (var pc = new PrincipalContext(ContextType.Domain, "DOMAIN_NAME"))
{
using (var user = UserPrincipal.FindByIdentity(pc, usr))
{
var isMember = false;
var authGroups = user?.GetAuthorizationGroups().GetEnumerator();
while (authGroups?.MoveNext() ?? false)
{
try
{
isMember = authGroups.Current.Name.ToLower().Contains(grp);
if (isMember) break;
}
catch
{
// ignored
}
}
authGroups?.Dispose();
return isMember;
}
}
}
I had the problem that if i am connected over VPN and use groups=UserPrincipal.GetGroups() then the Exception occures when iterating over the groups.
If someone want to read all groups of a user there is following possibility (which is faster than using GetGroups())
private IList<string> GetUserGroupsLDAP(string samAccountName)
{
var groupList = new List<string>();
var domainConnection = new DirectoryEntry("LDAP://" + serverName, serverUser, serverUserPassword); // probably you don't need username and password
var samSearcher = new DirectorySearcher();
samSearcher.SearchRoot = domainConnection;
samSearcher.Filter = "(samAccountName=" + samAccountName + ")";
var samResult = samSearcher.FindOne();
if (samResult != null)
{
var theUser = samResult.GetDirectoryEntry();
theUser.RefreshCache(new string[] { "tokenGroups" });
var sidSearcher = new DirectorySearcher();
sidSearcher.SearchRoot = domainConnection;
sidSearcher.PropertiesToLoad.Add("name");
sidSearcher.Filter = CreateFilter(theUser);
foreach (SearchResult result in sidSearcher.FindAll())
{
groupList.Add((string)result.Properties["name"][0]);
}
}
return groupList;
}
private string CreateFilter(DirectoryEntry theUser)
{
string filter = "(|";
foreach (byte[] resultBytes in theUser.Properties["tokenGroups"])
{
var SID = new SecurityIdentifier(resultBytes, 0);
filter += "(objectSid=" + SID.Value + ")";
}
filter += ")";
return filter;
}
I have a fairly odd requirement to be able to impersonate a user, when I'm already impersonating another, using C#.
I'm writing an app to allow the management of Active Directory users. This app will provide the ability for anyone in the company to view and maintain certain details about themselves (some of which will not actually be saved to Active Directory, but some of which will), for managers to be able to view and maintain details about their team, and for HR to be able to view and maintain details about anyone.
For obvious reasons I don't want to develop or test this against the live domain. We have recently ported all users over to this domain from another domain, which means I can actually test against the old domain without affecting anything. However, to enable me to do this I have to impersonate my old account on the old domain, which I do on loading the application.
Although for me everything will work fine as I'm setup as a domain admin, going forward obviously not all users will be domain admins, and won't be able to write to AD under their own account, and therefore we have another domain admin user setup specifically for this application, whenever data needs to be saved to AD that user is impersonated. This was working great before when I was testing against an Active Directory I'd setup on a virtual machine because I was logging onto the local domain, however that didn't allow me to step through the code in Visual Studio so debugging was slow, and hence I've stopped using that virtual machine and am using this old domain. Now I'm already impersonating another user (i.e. my old domain account), when it then tries to impersonate the domain admin user it fails with an "System.Security.SecurityException: Access is denied." exception. The line this fails on is just writing out some debugging information using "WindowsIdentity.GetCurrent().Name".
If I change my code so I'm actually logging in using the new domain admin rather than my old account, the first time it goes through it logs in successfully (so the credentials are correct), however when it then goes through and tries to do the same again to write to AD it fails with the above exception. Therefore I think it must be a problem with trying to do a nested impersonate.
Is it possible to do a nested impersonate?
Below is the code I'm using:
private static WindowsImpersonationContext ImpersonateUser(out string result, string sUsername,
string sDomain, string sPassword)
{
// initialize tokens
var pExistingTokenHandle = new IntPtr(0);
var pDuplicateTokenHandle = new IntPtr(0);
// if domain name was blank, assume local machine
if (sDomain == "")
{
sDomain = Environment.MachineName;
}
try
{
result = null;
const int logon32ProviderDefault = 0;
// create token
const int logon32LogonInteractive = 2;
// get handle to token
var bImpersonated = LogonUser(sUsername, sDomain, sPassword,
logon32LogonInteractive,
logon32ProviderDefault,
ref pExistingTokenHandle);
// did impersonation fail?
if (!bImpersonated)
{
var nErrorCode = Marshal.GetLastWin32Error();
result = "LogonUser() failed with error code: " + nErrorCode + "\r\n";
}
// Get identity before impersonation
result += string.Format("Before impersonation: {0}\r\n", WindowsIdentity.GetCurrent().Name);
var bRetVal = DuplicateToken(pExistingTokenHandle, (int)SecurityImpersonationLevel.SecurityImpersonation,
ref pDuplicateTokenHandle);
// did DuplicateToken fail?
if (bRetVal)
{
// create new identity using new primary token
var newId = new WindowsIdentity(pDuplicateTokenHandle);
var impersonatedUser = newId.Impersonate();
// check the identity after impersonation
result += "After impersonation: " + WindowsIdentity.GetCurrent().Name + "\r\n";
return impersonatedUser;
}
else
{
var nErrorCode = Marshal.GetLastWin32Error();
CloseHandle(pExistingTokenHandle); // close existing handle
result += "DuplicateToken() failed with error code: " + nErrorCode + "\r\n";
return null;
}
}
finally
{
// close handle(s)
if (pExistingTokenHandle != IntPtr.Zero)
{
CloseHandle(pExistingTokenHandle);
}
if (pDuplicateTokenHandle != IntPtr.Zero)
{
CloseHandle(pDuplicateTokenHandle);
}
}
}
When this is called for the nested impersonation which fails, "bImpersonated" is actually "true", as is bRetVal, which suggests its worked, however when it gets to "WindowsIdentity.GetCurrent().Name" it fails with the exception above.
I hope this makes sense, and would appreciate any assistance.
I am writing a standalone application that needs to, given a AD account name, figure out if the user is a member of a particular group. I am writing the application in .NET (C#). The structure in AD looks like this:
Organization
Team 1
David (user)
Groups
Application A
Team 1 (group from above)
Just listing the memberships for David will not show that he is a member of the Application A group.
I understand from Microsoft's documentation that (using the principals) I could simply use the IsInRole call, but I cannot find any case that doesn't require David to be logged on to the machine or running the application performing the check. I think my limited understanding of the security model also comes into play here.
Could someone please point me in the right direction? What I am looking for is hints on how to solve above (references, tips, snippets) in C#, without depending on David having to run any application.
Let me know if anything can be clarified.
Add a reference to DirectoryServices.AccountManagement
Then add a using statement:
using System.DirectoryServices.AccountManagement;
Then in your main procedure (or somewhere else, where required, call the Procedure IsMember:
string userName = "David";
string GroupName = "Team 1";
bool test = IsMember(userName, GroupName);
public static bool IsMember(string UserName, string GroupName)
{
try
{
UserPrincipal user = UserPrincipal.FindByIdentity(
new PrincipalContext(ContextType.Domain),
UserName);
foreach (Principal result in user.GetAuthorizationGroups())
{
if (string.Compare(result.Name, GroupName, true) == 0)
return true;
}
return false;
}
catch (Exception E)
{
throw E;
}
}
If David is in Team 1, the procedure will return true, otherwise false.
You can use UserPrincipal.FindByIdentity to obtain a UserPrincipal object from the directory. This isn't exactly like the other principal objects you may have found, but it does have an IsMemberOf method to allow you to query group membership.
I use this in my AD environment
var pc = new PrincipalContext(ContextType.Domain);
var group = GroupPrincipal.FindByIdentity(pc, "GROUPNAME");
var existsInGroup = group.GetMembers(true).Where(p => p.UserPrincipalName == "username#domain").Any();
If you don't want to check subgroups, pass false to GetMembers.
It doesn't require given user has to be logged on. Hope it helps.
What is the simplest and most efficient way in C# to check if a Windows user account name exists? This is in a domain environment.
Input: user name in [domain]/[user] format (e.g. "mycompany\bob")
Output: True if the user name exists, false if not.
I did find this article but the examples there are related to authenticating and manipulating user accounts, and they assume you already have a user distinguished name, whereas I am starting with the user account name.
I'm sure I can figure this out using AD, but before I do so I was wondering if there is a simple higher level API that does what I need.
* UPDATE *
There are probably many ways to do this, Russ posted one that could work but I couldn't figure out how to tweak it to work in my environment. I did find a different approach, using the WinNT provider that did the job for me:
public static bool UserInDomain(string username, string domain)
{
string path = String.Format("WinNT://{0}/{1},user", domain, username);
try
{
DirectoryEntry.Exists(path);
return true;
}
catch (Exception)
{
// For WinNT provider DirectoryEntry.Exists throws an exception
// instead of returning false so we need to trap it.
return false;
}
}
P.S.
For those who aren't familiar with the API used above: you need to add a reference to System.DirectoryServices to use it.
The link I found that helped me with this: How Can I Get User Information Using ADSI
The examples use ADSI but can be applied to .NET DirectoryServices as well. They also demonstrate other properties of the user object that may be useful.
The System.DirectoryServices namespace in the article is exactly what you need and intended for this purpose. If I recall correctly, it is a wrapper around the Active Directory Server Interfaces COM interfaces
EDIT:
Something like the following should do it (it could probably do with some checking and handling). It will use the domain of the current security context to find a domain controller, but this could easily be amended to pass in a named server.
public bool UserInDomain(string username, string domain)
{
string LDAPString = string.Empty;
string[] domainComponents = domain.Split('.');
StringBuilder builder = new StringBuilder();
for (int i = 0; i < domainComponents.Length; i++)
{
builder.AppendFormat(",dc={0}", domainComponents[i]);
}
if (builder.Length > 0)
LDAPString = builder.ToString(1, builder.Length - 1);
DirectoryEntry entry = new DirectoryEntry("LDAP://" + LDAPString);
DirectorySearcher searcher = new DirectorySearcher(entry);
searcher.Filter = "sAMAccountName=" + username;
SearchResult result = searcher.FindOne();
return result != null;
}
and tested with the following
Console.WriteLine(UserInDomain("username","MyDomain.com").ToString());
Found a simple way to do this if you're on a high enough framework version:
using System.DirectoryServices.AccountManagement;
bool UserExists(string userName, string domain) {
using (var pc = new PrincipalContext(ContextType.Domain, domain))
using (var p = Principal.FindByIdentity(pc, IdentityType.SamAccountName, userName)) {
return p != null;
}
}