Custom SAMLUserDetailsService not populating custom UserDetails - spring-security

Question

I have a Spring project and I'm converting my current authentication to use SAML2.
I have everything working as far as authentication, but I'm having difficulty in getting the SAML2 extension to insert my custom UserDetails object into the Spring Security Context authentication object.
I have a custom UserDetailsService, defined below:
public class SAMLAuthManager implements SAMLUserDetailsService {
private static final Logger logger = Logger.getLogger(JDBCAuthManager.class);
#Override
public Object loadUserBySAML(SAMLCredential credential) throws UsernameNotFoundException {
logger.info("Credential attributes: " + credential.getAttributes());
for (int x = 0; x < credential.getAttributes().size(); x++) {
Attribute attr = credential.getAttributes().get(x);
List<XMLObject> attrValues = attr.getAttributeValues();
StringBuilder strBuilder = new StringBuilder();
for (int g = 0; g < attrValues.size(); g++) {
XMLObject currObj = attrValues.get(g);
strBuilder.append(currObj.toString()).append(",");
}
strBuilder.deleteCharAt(strBuilder.length() - 1);
logger.info(attr.getFriendlyName() + ", " + strBuilder.toString());
}
String username = credential.getNameID().getValue();
userWrapper.setStaff(s);
logger.info("Returning wrapper: " + userWrapper);
return userWrapper;
} else {
return null;
}
}
}
I have also configured this userDetails in my security context config:
<bean id="samlAuthenticationProvider" class="org.springframework.security.saml.SAMLAuthenticationProvider">
<property name="userDetails" ref="samlUserDetails" />
</bean>
However, when I inspect the SecurityContextHolder, post authentication, this line:
SecurityContextHolder.getContext().getAuthentication().getCredentials();
returns an object of type org.springframework.security.saml.SAMLCredential.
I checked to see if Spring populated the Principal with the custom object (SecurityContextHolder.getContext().getAuthentication().getPrincipal()) but it did not, that's just a String with the username populated.
Any ideas?
Thanks

Answer 1

The principal is by default forced to be String (in order to always permit replication of Principal which was earlier an un-serializable NameID).
This can be changed by setting forcePrincipalAsString in SAMLAuthenticationProvider to false, which will make Spring SAML include your object provided by SAMLUserDetailsService as principal in the Authentication object.
The result of call to SAMLUserDetailsService is always available under SecurityContextHolder.getContext().getAuthentication().getDetails().