Ever have one of those days where you swear that you've written something, but can't find it? I could have sworn that I wrote this article before. Ah well.
--
It makes a lot of sense to use ACS to manage Identity Providers. It also makes sense to use Active Directory for letting users sign in to your cloud application. Therefore we would hope that ACS and ADFS play nicely together. It turns out they do. in a previous post I talked about federating ACS and ADFS, where ACS is an identity provider to ADFS. Now lets reverse it. We want users to be redirected to ACS, then to ADFS to sign in.
First things first. Lets log into our ACS namespace and navigate to the Identity Provider section, and then Add an Identity Provider:
From there we want to select what type of provider to use, and in this case we will select WS-Federation:
We are now provided with a form to fill out. There are five properties: Display Name, WS-Federation metadata, Login Link text, Image Url, and Email domain names.
Display name is fairly straightforward. What do you want the internal name of this IdP to be?
Next we need to provide a link to the Federation Metadata document that ADFS provides. The path is https://adfs.domain.com/FederationMetadata/2007-06/FederationMetadata.xml.
Then we give it a public name, such as "ObjectSharp Internal Users".
If we want to use an image instead if showing text, we can provide a path to the image.
Finally we are asked for a semicolon separated list of email domains. This may seem a bit confusing at first. Basically, it allows us to filter out the IdP from the Home Realm Discovery page, and requires that the user enter in their email address. That way, instead of seeing the "ObjectSharp Internal Users" link, we are provided a text box, where we need to enter an email address like ssyfuhs@objectsharp.com. ACS will then look up the domain in their list, and if there is a reference to it, it will redirect to the IdP.
This takes care of the ACS bit. just like in the previous post, you need to tell the other IdP about the other. So we need to tell ADFS that ACS will be calling. This is pretty simple. We just need to add a relying party to ADFS using the ACS metadata. You can find the ACS metadata under Application Integration:
There isn't much to federating ADFS to ACS and vice-versa.
When you start working with Windows Azure in your spare time there are quite a few things that you miss.
I knew that it was possible to manage Windows Azure with multiple accounts, but since I was the only one logging into my instance, I never bothered to look into it. Well as it turns out, I needed to be able to manage Azure from a separate Live ID. It's pretty simple to do. You get into your subscription, navigate to User Management under the Hosted Services tab, and then you add a new Co-Admin.
Turns out that you can't manage ACS this way though. You don't have access to the namespaces as the Co-Admin. Crap. That's really what I wanted to manage with the separate account. After a minute of swearing at the control panel, I logged into ACS with my original account and looked around.
Portal Administrators
Aha! It was staring me right in the face:
There is a full MSDN article on how to deal with Portal Administrators.
Upon clicking the link you are given a list of current administrators. I wanted to add one.
When you add an administrator you are given a list Identity Providers to choose from. Interesting.
This means that I can manage this ACS namespace using any IdP that I want. I already have ADFS created as an IdP, so I'm going to use it. Getting Single Sign-On is always a bonus.
It asks for a claim type. When the ACS management portal receives a token, it will look for this claim type and compare it's value to the Identity claim value. If it matches the value, you are authorized to manage the namespace. I chose email address. It seemed simple enough. To log in I just navigate to https://syfuhs2.accesscontrol.windows.net/ and then gives me the default Home Realm Discovery page:
I've already preconfigured ACS to redirect any email addresses with the objectsharp.com domain to our ADFS instance. Once I click submit it redirects to ADFS, I authenticate using Windows Authentication, and then I'm back at the ACS Control Panel. The next time I go to log in, a cookie will be there and the Home Realm Discovery page will see that I logged in with ADFS last time, so it will list that option first:
It just so happens that ObjectSharp is Awesome.
Now how cool is that?
One of the cornerstones of ADFS is the concept of federation (one would hope anyway, given the name), which is defined as a user's authentication process across applications, organizations, or companies. Or simply put, my company Contoso is a partner with Fabrikam. Fabrikam employees need access to one of my applications, so we create a federated trust between my application and their user store, so they can log into my application using their internal Active Directory. In this case, via ADFS.
So lets break this down into manageable bits.
First we have our application. This application is a relying party to my ADFS instance. By now hopefully this is relatively routine.
Next we have the trust between our ADFS and our partner company's STS. If the company had ADFS installed, we could just create a trust between the two, but lets go one step further and give anyone with a Live ID access to this application. Therefore we need to create a trust between the Live ID STS and our ADFS server.
This is easier than most people may think. We can just use Windows Azure Access Control Services (v2). ACS can be set up very easily to federate with Live ID (or Google, Yahoo, Facebook, etc), so we just need to federate with ACS, and ACS needs to federate with Live ID.
Creating a trust between ADFS and ACS requires two parts. First we need to tell ADFS about ACS, and second we need to tell ACS about ADFS.
To explain a bit further, we need to make ACS a Claims Provider to ADFS, so ADFS can call on ACS for authentication. Then we need to make ADFS a relying party to ACS, so ADFS can consume the token from ACS. Or rather, so ACS doesn't freak out when it see's a request for a token for ADFS.
This may seem a bit confusing at first, but it will become clearer when we walk through the process.
First we need to get the Federation Metadata for our ACS instance. In this case I've created an ACS namespace called "syfuhs2". The metadata can be found here: https://syfuhs2.accesscontrol.windows.net/FederationMetadata/2007-06/FederationMetadata.xml.
Next I need to create a relying party in ACS, telling it about ADFS. To do that browse to the Relying party applications section within the ACS management portal and create a new relying party:
Because ADFS natively supports trusts, I can just pass in the metadata for ADFS to ACS, and it will pull out the requisite pieces:
Once that is saved you can create a rule for the transform under the Rule Groups section:
For this I'm just going to generate a default set of rules.
This should take care of the ACS side of things. Next we move into ADFS.
Within ADFS we want to browse to the Claims Provider Trusts section:
And then we right-click > Add Claims Provider Trust
This should open a Wizard:
Follow through the wizard and fill in the metadata field:
Having Token Services that properly generate metadata is a godsend. Just sayin'.
Once the wizard has finished, it will open a Claims Transform wizard for incoming claims. This is just a set of claims rules that get applied to any tokens received by ADFS. In other words, what should happen to the claims within the token we receive from ACS?
In this case I'm just going to pass any claims through:
In practice, you should write a rule that filters out any extraneous claims that you don't necessarily trust. For instance, if I were to receive a role claim with a value "Administrator" I may not want to let it through because that could give administrative access to the user, even though it wasn't explicitly set by someone managing the application.
Once all is said and done, you can browse to the RP, redirect for authentication and will be presenting with this screen:
After you've made your first selection, a cookie will be generated and you won't be redirected to this screen again. If you select ACS, you then get redirected to the ACS Home Realm selection page (or directly to Live ID if you only have Live ID).
Sometime in the last few years Facebook has gotten stupidly popular. Given the massive user base, it actually makes a little bit of sense to take advantage of the fact that you can use them as an identity provider. Everyone has a Facebook account (except… me), and you can get a fair bit of information out of it on the user.
The problem though is that it uses OpenAuth, and I, of course, don't like OpenAuth. This makes it very unlikely for me to spend any amount time working with the protocol, and as such wouldn't jump at the chance to add it into an application. Luckily ACS supports Facebook natively – AND it's easy to setup.
First things first, we need to log into our ACS management portal, and select Identity Providers under Trust Relationships. Then we need to add a new Identity Provider:
Then we need to select Facebook as the type we want to add:
Once we start filling out the details for the federation we need to get some things from Facebook directly.
There are three fields we need to worry about, Application ID, Application secret, and Application permissions. We can get the first two from the settings page of our Facebook application, which you can get to at www.facebook.com/developers/.
You should create a separate application for each instance you create, and I'll explain why in a minute.
You then need the Application permissions. This is a list of claims to request access to from Facebook. The full list can be found here: http://developers.facebook.com/docs/authentication/permissions/, but for now email will suffice.
Once you have saved this identity provider you need to create a rule for each relying party. This will define how the claims are transformed before being sent to your relying party. If you already have rules set up you can modify one:
I'm pretty content with just using the default rules, which is to just pass everything, but you need to generate them first:
Once the rules have been generated you can save the rule.
Now you can test the federation.
It should fail.
If you watched everything in Fiddler you will see a chunk of JSON returned that looks something like:
{
"error": {
"type": "OAuthException",
"message": "Invalid redirect_uri: Given URL is not allowed by the Application configuration."
}
}
This is about my warning earlier about creating a separate application for each ACS namespace. Basically, Facebook doesn't like the request for authentication because it has no idea who the requestor is. Therefore I need to tell Facebook about my application.
To do this you need to get into the Web site settings for your application Facebook:
You will need to set the Site URL property to the ACS namespace:
Given the requirement for the FQDN, you need to create an application for each namespace you decide to create.
At this point federation with Facebook should now work. If you are using the default login page you should see something like this:
And if you sign-in you should get a token from Facebook which ACS will normalize, and then return to your relying party. Based on the permissions request you set above you should see something this:
** UPDATE **
Some of you may be wondering about this AccessToken claim. Part of the ACS configuration asks for a set of permissions to request, and these permissions are tied to this access token. Instead of receiving everything within claims, you need to make a separate call to Facebook to get these details by using the access token.
Dominick Baier has a good article explaining how to accomplish this: http://www.leastprivilege.com/AccessControlServiceV2AndFacebookIntegration.aspx.
** END UPDATE **
For those of you who want to federate with Facebook but don't like the idea of writing OpenAuth goo, ACS easily simplifies the process.
Part of the Mix11 announcement was that ACS v2 was released to production. It was actually released last Thursday but we were told to keep as quiet as possible so they could announce it at Mix. Here is the marketing speak:
The new ACS includes a plethora of new features that customers and partners have been asking with enthusiasm: single sign on from business and web identity providers, easy integration with our development tools, support for both enterprise-grade and web friendly protocols, out of the box integration with Facebook, Windows Live ID, Google and Yahoo, and many others.
Those features respond to such fundamental needs in modern cloud based systems that ACS has already become a key asset in many of our own offerings.
There is a substantial difference between v1 and v2. In v2, we now see:
Federation provider and Security Token Service (FINALLY!)
- Out of box federation with Active Directory Federation Services 2.0, Windows Live ID, Google, Yahoo, Facebook
New authorization scenarios
- Delegation using OAuth 2.0
Improved developer experience
- New web-based management portal
- Fully programmatic management using OData
- Works with Windows Identity Foundation
Additional protocol support
- WS-Federation, WS-Trust, OpenID 2.0, OAuth 2.0 (Draft 13)
That's a lot of stuff to keep up with, but luckily Microsoft has made it easier for us by giving us a whole whack of content to learn from.
First off, all of the training kits have now been updated to support v2:
Second, there are a bunch of new Channel9 videos just released:
Third, and finally, the Claims Based Identity and Access Control Guide was updated!
Talk about a bunch of awesome stuff.
So how do you know when Windows Azure Access Control Services has upgraded to V2? You get federation metadata…
Or you follow the Windows Azure App Fabric team blog!
I have been waiting MONTHS for this release, begging and pleading with Microsoft to get more information on when the big day would come. Needless to say I am super excited!
This version adds:
Federation provider and Security Token Service (FINALLY!)
- Out of box federation with Active Directory Federation Services 2.0, Windows Live ID, Google, Yahoo, Facebook
New authorization scenarios
- Delegation using OAuth 2.0
Improved developer experience
- New web-based management portal
- Fully programmatic management using OData
- Works with Windows Identity Foundation
Additional protocol support
- WS-Federation, WS-Trust, OpenID 2.0, OAuth 2.0 (Draft 13)
Now to just migrate from Appfabric Labs…
Every couple of weeks I start up Autoruns to see what new stuff has added itself to Windows startup and what not (screw you Adobe – you as a software company make me want to swear endlessly). Anyway, a few months ago around the time the latest version of Windows Live Messenger and it’s suite RTM’ed I poked around to see if anything new was added. Turns out there was:
A new credential provider was added!
Interesting.
Not only that, it turns out a couple Winsock providers were added too:
I started poking around the DLL’s and noticed that they don’t do much. Apparently you can use smart cards for WLID authentication. I suspect that’s what the credential provider and associated Winsock Provider is for, as well as part of WLID’s sign-on helper so credentials can be managed via the Credential Manager:
Ah well, nothing too exciting here.
Skip a few months and something occurred to me. Microsoft was able to solve part of the Claims puzzle. How do you bridge the gap between desktop application identities and web application identities? They did part of what CardSpace was unable to do because CardSpace as a whole didn’t really solve a problem people were facing. The problem Windows Live ran into was how do you share credentials between desktop and web applications without constantly asking for the credentials? I.e. how do you do Single Sign On…
This got me thinking.
What if I wanted to step this up a smidge and instead of logging into Windows Live Messenger with my credentials, why not log into Windows with my Windows Live Credentials?
Yes, Windows. I want to change this:
Question: What would this solve?
Answer: At present, nothing ground-breakingly new. For the sake of argument, lets look at how this would be done, and I’ll (hopefully) get to my point.
First off, we need to know how to modify the Windows logon screen. In older versions of Windows (versions older than 2003 R2) you had to do a lot of heavy lifting to make any changes to the screen. You had to write your own GINA which involved essentially creating your own UI. Talk about painful.
With the introduction of Vista, Microsoft changed the game when it came to custom credentials. Their reasoning was simple: they didn’t want you to muck up the basic look and feel. You had to follow their guidelines.
As a result we are left with something along the lines of these controls to play with:
The logon screen is now controlled by Credential Providers instead of the GINA. There are two providers built into Windows by default, one for Kerberos or NTLM authentication, and one for Smart Card authentication.
The architecture looks like:
When the Secure Attention Sequence (CTRL + ALT + DEL / SAS) is called, Winlogon switches to a different desktop and instantiates a new instance of LogonUI.exe. LogonUI enumerates all the credential provider DLL’s from registry and displays their controls on the desktop.
When I enter in my credentials they are serialized and supposed to be passed to the LSA.
Once the LSA has these credentials it can then do the authentication.
I say “supposed” to be passed to the LSA because there are two frames of thought here. The first frame is to handle authentication within the Credential Provider itself. This can cause problems later on down the road. I’ll explain why in the second frame.
The second frame of thought is when you need to use custom credentials, need to do some funky authentication, and then save save the associated identity token somewhere. This becomes important when other applications need your identity.
You can accomplish this via what’s called an Authentication Package.
When a custom authentication package is created, it has to be designed in such a way that applications cannot access stored credentials directly. The applications must go through the pre-canned MSV1_0 package to receive a token.
Earlier when I asked about using Windows Live for authentication we would need to develop two things: a Credential Provider, and a custom Authentication Package.
The logon process would work something like this:
- Select Live ID Credential Provider
- Type in Live ID and Password and submit
- Credential Provider passes serialized credential structure to Winlogon
- Winlogon passes credentials to LSA
- LSA passes credential to Custom Authentication Package
- Package connects to Live ID STS and requests a token with given credentials
- Token is returned
- Authentication Package validated token and saves it to local cache
- Package returns authentication result back up call stack to Winlogon
- Winlogon initializes user’s profile and desktop
I asked before: What would this solve?
This isn’t really a ground-breaking idea. I’ve just described a domain environment similar to what half a million companies have already done with Active Directory, except the credential store is Live ID.
On it’s own we’ve just simplified the authentication process for every home user out there. No more disparate accounts across multiple machines. Passwords are in sync, and identity information is always up to date.
What if Live ID sets up a new service that lets you create access groups for things like home and friends and you can create file shares as appropriate. Then you can extend the Windows 7 Homegroup sharing based on those access groups.
Wait, they already have something like that with Skydrive (sans Homegroup stuff anyway).
Maybe they want to use a different token service.
Imagine if the user was able to select the “Federated User” credential provider that would give you a drop down box listing a few Security Token Services. Azure ACS can hook you up.
Imagine if one of these STS’s was something everyone used *cough* Facebook *cough*.
Imagine the STS was one that a lot of sites on the internet use *cough* Facebook *cough*.
Imagine if the associated protocol used by the STS and websites were modified slightly to add a custom set of headers sent to the browser. Maybe it looked like this:
Relying-Party-Accepting-Token-Type: urn:sometokentype:www.somests.com
Relying-Party-Token-Reply-Url: https://login.myawesomesite.com/auth
Finally, imagine if your browser was smart enough to intercept those headers and look up the user’s token, check if they matched the header ”Relying-Party-Accepting-Token-Type” and then POST the token to the given reply URL.
Hmm. We’ve just made the internet SSO capable.
Now to just move everyone’s cheese to get this done.
Patent Pending. 