(As experienced in Server 2012 R2 and Tableau Server 10.2)
TL;DR: Follow Tableau’s guide but use SHA-1 on the ADFS side, and map SAMAccountName to the “email” Outgoing Claim Type
Looking around the web, it seems like using Microsoft’s ADFS with Tableau Server for Single Sign-On (SSO) is widespread and no big deal to setup. Sure, the steps available on Tableau’s site look a little long, but it’s all pretty straightforward. However, there are a couple things that get left out.
The first issue, which has to do with the Secure Hashing Algorithm (SHA) used to sign requests and responses, is easy to mitigate. When I read a support article from Tableau, I got the sense that Tableau should support SHA-256. However, whether I ran the recommended tabadmin command or not, I always ended up with a failed authentication attempt and the following error on the ADFS server:
SAML request is not signed with expected signature algorithm. SAML request is signed with signature algorithm http://www.w3.org/2001/04/xmldsig-more#rsa-sha256 . Expected signature algorithm is http://www.w3.org/2000/09/xmldsig#rsa-sha1
Meanwhile, Tableau Server presented the following error in C:\ProgramData\Tableau\Tableau Server\data\tabsvc\logs\vizportal\vizportal-x.log:
org.opensaml.common.SAMLException: Received response has invalid status code
The fix? Tell ADFS to use SHA-1 for the Tableau relying party. You or your ADFS admin can do this with the following steps (based on Server 2012 R2):
- Log into the ADFS server
- Open AD FS Management
- Go to Trust Relationships -> Relying Party Trusts
- Double-click the Tableau Relying Party (the identifier column should match what you put in the SAML entity ID field back on your Tableau SAML config)
- Click the Advanced tab
- Set the Secure hash algorithm drop-down to SHA-1
- Click OK
No ADFS restart will be necessary.
Now, of course, there are security implications with this change. SHA-1 is no longer considered secure, so you should first assess the potential risk for your organization.
Onto the second–and potentially more interesting/confounding–issue. Every guide I checked on how to configure ADFS listed the following attributes in the claims rule:
- SAM-Account-Name -> Name ID
- SAM-Account-Name -> username
- (optional) Surname -> LastName
- (optional) GivenName -> FirstName
This is definitely what ADFS had configured, but it wasn’t working. I finally turned to the previously-mentioned vizportal log and found this:
org.springframework.security.authentication.AuthenticationServiceException: Incoming SAML message has no valid value for email attribute. Please verify ServiceProvider configuration in Identity Provider.
So… Despite what the docs say, Tableau wants an email attribute? In some cases, this is no big deal. Simply edit your Issuance Transform Rules, and add an attribute that maps “E-Mail-Addresses” to the “email” outgoing claim type. Where it gets tricky is when your email address is not the same thing as your username @ your AD domain. Why would this matter? Because, even though Tableau is receiving an attribute called “username,” it tries to extract domain and username from the email address.
Say your email address is firstname.lastname@example.org. When this gets passed to Tableau, Tableau breaks it apart and tries to sign in as contoso.com\jon.doe. If jon.doe is your username/SAMAccountName and your domain is known internally as contoso.com, then that’s great. However, if your username is actually jdoe and your internal domain is fabrikam.com, this is going to fail with a vizportal error like this:
2017-12-14 10:26:40.253 -0500 (,,,) catalina-exec-4 : INFO com.tableausoftware.domain.user.saml.SAMLExtendedProcessingFilter – Using domain contoso.com extracted from email in saml response for username email@example.com
2017-12-14 10:26:40.253 -0500 (,,,) catalina-exec-4 : INFO com.tableausoftware.domain.user.saml.SAMLExtendedProcessingFilter – Using fully qualified username contoso.com\jon.doe from saml response
2017-12-14 10:26:40.253 -0500 (,,,) catalina-exec-4 : INFO com.tableausoftware.domain.user.saml.SAMLExtendedProcessingFilter – SAML IDP login was successful, proceeding to create session for username : contoso.com\jon.doe authUserId : Optional.absent() displayName : Optional.absent() email : Optional.of(firstname.lastname@example.org) logoutSupported : true on provided target site Optional.absent()
2017-12-14 10:26:41.563 -0500 (,,,) catalina-exec-4 : ERROR com.tableausoftware.domain.user.saml.SAMLExtendedProcessingFilter – SAML Authentication Failed, please contact the administrator.
Fortunately, you still have a couple easy options. First, if your UserPrincipalName uses your standard fabrikam.com domain, rather than something like finance.fabrikam.com, you could map that to the “email” attribute. Alternatively, you could just map SAMAccountName to the “email” attribute. If Tableau doesn’t see an “@” symbol in the email, it will simply pass the username along as-is. Problem solved.
I plan to raise this with Tableau support. It could be that I’ve got something wrong or need to update (yes, I do, but I haven’t seen this mentioned as a known issue/bug fix). But, if you need to move past this quickly, perhaps these tips will help. Good luck!