How-to: Implement multi-tenancy

[arfatbk]

I am thinking of A single Authorization server in an organization providing identity federation for multiple clients(tenants), where tenant data should be isolated from each other.

Other OAuth servers like KeyCloak provide Multi-tenancy. https://www.keycloak.org/docs/latest/securing_apps/index.html#_multi_tenancy

One of the following approaches can be configured:

Separate Schema – one schema per tenant in the same physical database instance
Separate Database – one separate physical database instance per tenant
Partitioned (Discriminator) Data – the data for each tenant is partitioned by a discriminator value(ex. A column for tenant identifier)

Organization can choose which of the above approach is suitable for any given tenant. For example 'A' tenants wants it's data completed isolated and is ok with separate physical database. Where 'B' tenant is ok with separate schema in shared physical database etc.

I am not sure if it is in roadmap or as a framework we want to implement this. Can anyone please direct me to resources if you have one that would be awesome.
Thanks

Related gh-499

[jgrandja]

@arfatbk Support for multi-tenancy would be implemented in a product implementation of an OAuth/OIDC server, e.g. Keycloak. This isn't a feature the framework would implement.

I changed the title to a "How-to Guide" to see if there is demand from the community for this. If there is enough upvotes, we can consider adding a How-to guide.

I would also recommend posting this question on Stack Overflow and linking the post back to this issue.

[sjohnr]

Here's the stack overflow question related to this issue. It looks like I suggested @arfatbk open an issue. I think it's a good idea to see if the community has interest via upvotes (👍).

[Basit-Mahmood]

@sjohnr Hi. Hope you are doing well. Actually I was implementing it and I stuck at a point. I am not sure it is right place to ask if I stuck at some point or what. Anyways for AuthorizationCode grant type flow. I am sending request parameter name tenantDatabaseName. What I did I added a filter in my AuthoirzationServer Configuration. http.addFilterBefore(new TenantFilter(), OAuth2AuthorizationRequestRedirectFilter.class); Here is the configuration.

`@Import({OAuth2RegisteredClientConfiguration.class})
 public class AuthorizationServerConfiguration {
    @Bean
    @Order(Ordered.HIGHEST_PRECEDENCE)
    public SecurityFilterChain authorizationServerSecurityFilterChain(HttpSecurity http) throws Exception {
	
        OAuth2AuthorizationServerConfigurer<HttpSecurity> authorizationServerConfigurer = new OAuth2AuthorizationServerConfigurer<>();
        http.apply(authorizationServerConfigurer.tokenEndpoint((tokenEndpoint) -> tokenEndpoint.accessTokenRequestConverter(
		new DelegatingAuthenticationConverter(Arrays.asList(
			new OAuth2AuthorizationCodeAuthenticationConverter(),
			new OAuth2RefreshTokenAuthenticationConverter(),
			new OAuth2ClientCredentialsAuthenticationConverter(),
			new OAuth2ResourceOwnerPasswordAuthenticationConverter()))
	)));
	
        authorizationServerConfigurer.authorizationEndpoint(authorizationEndpoint -> authorizationEndpoint.consentPage(CUSTOM_CONSENT_PAGE_URI));
        RequestMatcher endpointsMatcher = authorizationServerConfigurer.getEndpointsMatcher();
	
        http
	    .requestMatcher(endpointsMatcher)
	    .authorizeRequests(authorizeRequests -> authorizeRequests.anyRequest().authenticated())
	    .csrf(csrf -> csrf.ignoringRequestMatchers(endpointsMatcher))
	    .apply(authorizationServerConfigurer)
	    .and()
	    .apply(new FederatedIdentityConfigurer());
	
	    http.addFilterBefore(new TenantFilter(), OAuth2AuthorizationRequestRedirectFilter.class);
	    SecurityFilterChain securityFilterChain = http.formLogin(Customizer.withDefaults()).build();
	    addCustomOAuth2ResourceOwnerPasswordAuthenticationProvider(http);
	    return securityFilterChain;
    }
        .....
}

`
Here is the filter

`public class TenantFilter extends OncePerRequestFilter {
     @Override
     protected void doFilterInternal(HttpServletRequest request, HttpServletResponse response, FilterChain filterChain) throws ServletException, IOException {
	
	String requestUrl = request.getRequestURL().toString();
	
	if (!requestUrl.endsWith("/oauth2/jwks")) {
	    String tenantDatabaseName = request.getParameter(Constant.TENANT_DATABASE_NAME);
	    if(StringUtils.hasText(tenantDatabaseName)) {
	        LOGGER.info("tenantDatabaseName request parameter is found");
		TenantDBContextHolder.setCurrentDb(tenantDatabaseName);
            } else {
	        LOGGER.info("No tenantDatabaseName request parameter is found");
		response.setStatus(HttpServletResponse.SC_BAD_REQUEST);
		response.setContentType(MediaType.APPLICATION_JSON_VALUE);
		response.getWriter().write("{'error': 'No tenant request parameter supplied'}");
		response.getWriter().flush();
		return;
            }
	}
	filterChain.doFilter(request, response);
    }
}`

Now when request comes for authorization code grant type flow. This filter intercept the request. But in OAuth2AuthorizationEndpointFilter it is check if user is authenticated. The following line is present in OAuth2AuthorizationEndpointFilter.java's doFilterInternal() method

` if (!authorizationCodeRequestAuthenticationResult.isAuthenticated()) {	
    // If the Principal (Resource Owner) is not authenticated then
    // pass through the chain with the expectation that the authentication process
    // will commence via AuthenticationEntryPoint
    filterChain.doFilter(request, response);
    return;
}`

So now it throws the exception. Ultimately comes to LoginUrlAuthenticationEntryPoint and it redirects to Login Page using DefaultRedirectStrategy. As it is redirecting so now there is no tenantDatabaseName request parameter. But I overridden the method. Here what I did. Basically I am just appending the request parameter. So when it redirects I get the parameter.

`public class TenantLoginUrlAuthenticationEntryPoint extends LoginUrlAuthenticationEntryPoint {

    public TenantLoginUrlAuthenticationEntryPoint(String loginFormUrl) {
            super(loginFormUrl);
    }

    @Override
    protected String determineUrlToUseForThisRequest(HttpServletRequest request, HttpServletResponse response,
		AuthenticationException exception) {
	String tenantDatabaseNameParamValue = request.getParameter(Constant.TENANT_DATABASE_NAME);
	String redirect = super.determineUrlToUseForThisRequest(request, response, exception);
	String url = UriComponentsBuilder.fromPath(redirect).queryParam(Constant.TENANT_DATABASE_NAME, tenantDatabaseNameParamValue).toUriString();
	return url;
    }
}`

Then in the Login controller I get the parameter.

`@Controller
 public class LoginController {
    @GetMapping("/login")
    public String login(@Valid @ModelAttribute RedirectModel redirectModel,  Model model, BindingResult result) {
	if (!result.hasErrors()) {
		String tenantDatabaseName = redirectModel.getTenantDatabaseName();
		String currentDb = TenantDBContextHolder.getCurrentDb();
		LOGGER.info("Current database is {}", currentDb);
		LOGGER.info("Putting {} as tenant database name in model. So it can be set as a hidden form element ", tenantDatabaseName);
		model.addAttribute(Constant.TENANT_DATABASE_NAME, tenantDatabaseName);
	}
	return "login";
    }
 }`

Now I set it as a hidden form element. Then I created a custom filter. Added it before UsernamePasswordAuthrntiationFilter. I get the parameter value. I set it in the Thread Local Context and it works. I mean it connects to right database.

Now after validating user it goes back to client and again comes to server with the tenantDatabaseName request paamter. But this time it shows the Consent page. Now here is the code in the OAuth2AuthorizationEndpointFilter. It can be seen that in the sendAuthorizationConsent() method it is adding request parameters client_id, scope and state. And I get these parameters in the Consent Controller.

`public final class OAuth2AuthorizationEndpointFilter extends OncePerRequestFilter {
     @Override
     protected void doFilterInternal(HttpServletRequest request, HttpServletResponse response, FilterChain filterChain)
         throws ServletException, IOException {
         if (!this.authorizationEndpointMatcher.matches(request)) {
	      filterChain.doFilter(request, response);
	      return;
	}

	try {
            ....
            if (authorizationCodeRequestAuthenticationResult.isConsentRequired()) {
	        sendAuthorizationConsent(request, response, authorizationCodeRequestAuthentication, authorizationCodeRequestAuthenticationResult);
		return;
	    }
        }
    }

    private void sendAuthorizationConsent(HttpServletRequest request, HttpServletResponse response,
	OAuth2AuthorizationCodeRequestAuthenticationToken authorizationCodeRequestAuthentication,
	OAuth2AuthorizationCodeRequestAuthenticationToken authorizationCodeRequestAuthenticationResult) throws IOException {

	String clientId = authorizationCodeRequestAuthenticationResult.getClientId();
	Authentication principal = (Authentication) authorizationCodeRequestAuthenticationResult.getPrincipal();
	Set<String> requestedScopes = authorizationCodeRequestAuthentication.getScopes();
	Set<String> authorizedScopes = authorizationCodeRequestAuthenticationResult.getScopes();
	String state = authorizationCodeRequestAuthenticationResult.getState();

	if (hasConsentUri()) {
		String redirectUri = UriComponentsBuilder.fromUriString(resolveConsentUri(request))
				.queryParam(OAuth2ParameterNames.SCOPE, String.join(" ", requestedScopes))
				.queryParam(OAuth2ParameterNames.CLIENT_ID, clientId)
				.queryParam(OAuth2ParameterNames.STATE, state)
				.toUriString();
		this.redirectStrategy.sendRedirect(request, response, redirectUri);
	} else {
		DefaultConsentPage.displayConsent(request, response, clientId, principal, requestedScopes, authorizedScopes, state);
	}
    }

 }
`

My question is how can I customized the sendAuthorizationConsent() method so I can include my tenantDatabeName request parameter too. ? Is there any way that I can modify AuthorizationServer configuration or am I doing it in the right way. Is there any better way of doing it ?

Like in the configuration we are customizing the consent page authorizationServerConfigurer.authorizationEndpoint(authorizationEndpoint -> authorizationEndpoint.consentPage(CUSTOM_CONSENT_PAGE_URI));

Is there similar way I can customize this ?

If you can assist me it would be very helpful.

Thanks

[sjohnr]

@Basit-Mahmood, thanks for getting in touch, but it feels like this is a question that would be better suited to Stack Overflow. We prefer to use GitHub issues only for bugs and enhancements. Feel free to update this issue with a link to the re-posted question (so that other people can find it) and I will be happy to take a look.

If you'd prefer to discuss the issue more to get ideas, I'd also be happy to discuss it with you on the #spring-security gitter channel.

I should mention that I have not actually implemented SAS as a multi-tenant application either, so I can only provide ideas for you at the moment.

[Basit-Mahmood]

@sjohnr Thank you so much for the reply. Yes I need your idea how to get through it. I remember when I was trying to implement password grant type then I stuck that how can I add Password Converter using the Authorization server configuration. Then you replied that I can either use the following code

` http.apply(authorizationServerConfigurer.withObjectPostProcessor(new ObjectPostProcessor<OAuth2TokenEndpointFilter>() {
	@Override
	public <O extends OAuth2TokenEndpointFilter> O postProcess(O oauth2TokenEndpointFilter) {
		oauth2TokenEndpointFilter.setAuthenticationConverter(new DelegatingAuthenticationConverter(
			Arrays.asList(
				new OAuth2AuthorizationCodeAuthenticationConverter(),
				new OAuth2RefreshTokenAuthenticationConverter(),
				new OAuth2ClientCredentialsAuthenticationConverter(),
			        new OAuth2ResourceOwnerPasswordAuthenticationConverter())));
			return oauth2TokenEndpointFilter;
		}
	    })
	);
`

or this

` http.apply(authorizationServerConfigurer.tokenEndpoint((tokenEndpoint) -> tokenEndpoint.accessTokenRequestConverter(
	new DelegatingAuthenticationConverter(Arrays.asList(
		new OAuth2AuthorizationCodeAuthenticationConverter(),
		new OAuth2RefreshTokenAuthenticationConverter(),
		new OAuth2ClientCredentialsAuthenticationConverter(),
		new OAuth2ResourceOwnerPasswordAuthenticationConverter()))
)));
`

And this was very helpful. Similarly I want to ask is there any way that I can customize the OAuth2AuthorizationEndpointFilter using some AuthorizationServerConfiguration ? If there is any.

If customizing is not possible in this version of Authorization Server Configuration. Then I think may be for now I can change the end point /oauth2/authorize and provide another filter. And this new filter would call instead of the original one for the authorization code grant type flow. I think now in Authorization Server Configuration we can change the end points. But I am not sure that if we change the end point then we also need to provide another filter or it just override the DEFAULT_AUTHORIZATION_ENDPOINT_URI in OAuth2AuthorizationEndpointFilter.

Actually I am asking it here because As Authorization Server Server is expanding. Which is very great. May be my question can trigger something that you guys think, ok we can include it in the later version of Authorization Server because it can be useful.
It is just my thinking.

Thanks

[sjohnr]

Thanks @Basit-Mahmood. I appreciate how excited you are to contribute!

I do want to be conscious of the fact that extended discussions about how to do something in your own application are often off-topic for the issue at hand, which feels like the case here at the moment. We could circle back to this issue with ideas we come up with together though. For now, please post a question on stackoverflow or start a thread on gitter and I will jump right in to discuss it with you!

[zmlgit]

I expand the RegisteredClient to TenantRegisteredClient with a tenantId field, then the clients could use stardar third party library for exchange, but I'm facing a problem, I don't know how to pick the tenantId from the securityContext, because when
the request redirected to /login page, the SecurityContext becomes a AnonymousAuthenticationToken

[Basit-Mahmood]

@zmlgit you can take a look at the stack overflow post Stack Overflow I described their that how to get the tenant Id for authorization code grant type flow when it redirects to login page and after login. May be it would help you.

Thanks & Regards
Basit Mahmood Ahmed

[Yneth]

I expand the RegisteredClient to TenantRegisteredClient with a tenantId field, then the clients could use stardar third party library for exchange, but I'm facing a problem, I don't know how to pick the tenantId from the securityContext, because when the request redirected to /login page, the SecurityContext becomes a AnonymousAuthenticationToken

if it is still an issue for you, there is a way you can solve it.
As soon as you go to /oauth2/authorize which redirects you to /oauth2/login your initial request /oauth2/authorize is saved in the HttpSession and you can retrieve your client_id. Lookup RegisteredClient from the database get your tenantId and put it into the HttpSession