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Area

authentication

Describe the bug

During Keycloak browser interface log-in, Kerberos authentication fails for any user name + domain shorter than 14 characters. (e.g. user@site logging into site.com domain)

I traced this down as I was receiving an error message when a user attempted to log in to a specific domain:

Uncaught server error: org.bouncycastle.crypto.fips.FipsUnapprovedOperationError: salt must be at least 128 bits

Enabling further logging showed the following for what the "salt" was:

>>>Pre-Authentication Data:
                PA-DATA type = 19
                PA-ETYPE-INFO2 etype = 18, salt = DEPOT.NAMEusera, s2kparams = null

I had a hunch, so I created a user with a longer name "longname" in the domain DEPOT.NAME and it worked flawlessly. The "salt" in this case is DEPOT.NAMElongname which worked fine.

Version

26.0

Regression

• The issue is a regression

Expected behavior

Expected behavior is that a user in a domain can have any length username/domain and not fail authentication on FIPS-enabled systems.

Actual behavior

Usernames + FQDN of less than 14 characters (128 bits hashed) fail. (user@site.com would not work)

How to Reproduce?

Follow FIPS configuration documentation provided to start a FIPS-approved version of keycloak container on a RHEL9 system that is FIPS-enabled and FIPS-strict. Create a domain with a FQDN and a user in that domain that are both totaling length < 14. Configure RHEL9 system to use Kerberos and join domain. Enable Kerberos User Federation in Keycloak. Log-in to the web interface with the username and domain.

Anything else?

Unfortunately I can't provide the logs due to it occurring on an air-gapped network.

The issue may be as simple as improving the documentation to be clearer about a setting that I'm missing, or it could be more complicated as making the "salt" that is generated in the KDC configuration be a minimum of 14 characters so that the FIPS-approved hashing algorithms work with shorter user+domain combos.

I noticed that in the documentation for the fips guide that there's a section for User passwords being longer than 14 characers. It suggests using the option --spi-password-hashing-pbkdf2-sha512-max-padding-length=14 Is there an option like that for user hashing?