spring-security saml2 : How to obtain the current user?

问题

I'm working with spring-security and spring-security-saml2-service-provider with versions 5.2.0.RELEASE. I'm trying after authentication by IDP to obtain the current Assertion in order to map it to a user in our local system. I use this code to obtain the Saml2Authentication object

@Component
@Log4j
public class EventListener implements ApplicationListener<InteractiveAuthenticationSuccessEvent> {
    @Override
    public void onApplicationEvent(InteractiveAuthenticationSuccessEvent interactiveAuthenticationSuccessEvent) {
        Object principal = interactiveAuthenticationSuccessEvent.getAuthentication().getPrincipal();
        Saml2Authentication authentication = (Saml2Authentication)interactiveAuthenticationSuccessEvent.getAuthentication()

But I cannot get the user. I can get the saml2 response (authentication.getSaml2Response) but I'm not sure how to obtain the assertion with the id of the user.

Really, I would like to do Retrieve Attributes and NameID from a SAML Response (XML) in the Java Code. Not sure if there is something in spring-security that can help me.

Update So after a bit of work, I get the attributes using the OpenSAML library and parsing the SAMLv2 response. I don't know if this is the correct way to do it

@Override
    public void onApplicationEvent(InteractiveAuthenticationSuccessEvent interactiveAuthenticationSuccessEvent) {
        Saml2Authentication authentication = (Saml2Authentication) interactiveAuthenticationSuccessEvent.getAuthentication();
        try {

            Document messageDoc;
            BasicParserPool basicParserPool = new BasicParserPool();
            basicParserPool.initialize();
            InputStream inputStream = new ByteArrayInputStream(authentication.getSaml2Response().getBytes());
            messageDoc = basicParserPool.parse(inputStream);
            Element messageElem = messageDoc.getDocumentElement();
            Unmarshaller unmarshaller = XMLObjectProviderRegistrySupport.getUnmarshallerFactory().getUnmarshaller(messageElem);
            XMLObject samlObject = unmarshaller.unmarshall(messageElem);
            Response response = (Response) samlObject;
            response.getAssertions().forEach(assertion -> {
                assertion.getAttributeStatements().forEach(attributeStatement ->
                {
                    attributeStatement.getAttributes().forEach(attribute -> {
                        log.error("Names:" + attribute.getName() + getAttributesList(attribute.getAttributeValues()));
                    });
                });
            });
        } catch (Exception e) {
            log.error(e);
        }
    }

    private List<String> getAttributesList(Collection<XMLObject> collection) {
        return collection.stream().map(this::getAttributeValue)
                .collect(Collectors.toList());
    }

    private String getAttributeValue(XMLObject attributeValue) {
        return attributeValue == null ?
                null :
                attributeValue instanceof XSString ?
                        getStringAttributeValue((XSString) attributeValue) :
                        attributeValue instanceof XSAnyImpl ?
                                getAnyAttributeValue((XSAnyImpl) attributeValue) :
                                attributeValue.toString();
    }

    private String getStringAttributeValue(XSString attributeValue) {
        return attributeValue.getValue();
    }

    private String getAnyAttributeValue(XSAnyImpl attributeValue) {
        return attributeValue.getTextContent();
    }

回答1:

By default Spring SAML Security is using the value of the NameID in the Subject element to set the 'username'. If 'transient NameID format', the value has to be a different/unique one for every SSO flow per SAML spec.

You can implement your own UserDetailsService which implements org.springframework.security.saml.userdetails.SAMLUserDetailsService in method loadUserBySAML you can extract the SAML attributes

@Override
public Object loadUserBySAML(SAMLCredential credential) throws UsernameNotFoundException {
  final List<Attribute> attributesFromAttributeStatement = credential.getAttributes();

  final String userName = getUserNameValueFromAttribute(attributesFromAttributeStatement);

  // if needed calculate authorities
  final List<GrantedAuthority> grantedAuthorities = getGrantedAuthorities();
  final User authenticatedUser = new User(userName, "", grantedAuthorities);
  return authenticatedUser;
}

来源：https://stackoverflow.com/questions/58400571/spring-security-saml2-how-to-obtain-the-current-user