How to secure Vaadin flow application with Spring Security

SrThompson :

I'm trying to integrate vaadin 10 with spring security (using the spring project base provided by vaadin), and I'm confused on how they interact exactly. If I go to a protected url (in this example, "/about") typing it directly in the browser, the login page shows up. If I go to the same URL by clicking in a link from the UI, the page shows up even if I'm not authenticated. So I guess that Vaadin is not going through Spring Security's filter chain, but then how do I secure my resources inside the UI, and how can I share the authenticated user between vaadin and spring? Am I supposed to implement security twice? The documentation available doesn't seem to cover this, and every link on the internet has examples with Vaadin 7-8, which I've never used and seems to work differently from 10+.

Does anyone know any resource about this, or can you enlighten me on how all of this works together so I can know what I'm doing?

Here's my security configuration:

@Configuration
@EnableWebSecurity
public class SecurityConfig extends WebSecurityConfigurerAdapter {

    private static final String[] ALLOWED_GET_URLS = {
        "/",
        //"/about",
        "/login/**",
        "/frontend/**",
        "/VAADIN/**",
        "/favicon.ico"
    };

    private static final String[] ALLOWED_POST_URLS = {
        "/"
    };

    //@formatter:off
    @Override
    protected void configure(HttpSecurity http) throws Exception {
        http
            .csrf()
                .disable()
            .authorizeRequests()
                .mvcMatchers(HttpMethod.GET, ALLOWED_GET_URLS)
                    .permitAll()
                .mvcMatchers(HttpMethod.POST, ALLOWED_POST_URLS)
                    .permitAll()
                .anyRequest()
                    .fullyAuthenticated()
             .and()
                .formLogin()
                    .loginPage("/login")
                    .permitAll()
            .and()
                .logout()
                    .logoutSuccessUrl("/")
                    .permitAll();
    }
    //@formatter:on

}

Youness :

Using Vaadin Flow (12.0.2), Spring Boot Starter (2.0.2.RELEASE) and Spring Boot Security, basically, I found authorizing based on role/authority using the following ways;

Route/Context based role/authority managment

Spring security (HttpSecurity)
Vaadin API (BeforeEnterListener and Route/Navigation API)

Business unit role/authority management

Inside the code using HttpServletRequest.isUserInRole method

Let's start with a simple example of Spring Security configuration;

@Configuration
@EnableWebSecurity
public class WebSecurityConfig
        extends WebSecurityConfigurerAdapter {

    @Override
    protected void configure(HttpSecurity http) throws Exception {
        http
                .csrf().disable() // CSRF is handled by Vaadin: https://vaadin.com/framework/security
                .exceptionHandling().accessDeniedPage("/accessDenied")
                .authenticationEntryPoint(new LoginUrlAuthenticationEntryPoint("/login"))
                .and().logout().logoutSuccessUrl("/")
                .and()
                .authorizeRequests()
                // allow Vaadin URLs and the login URL without authentication
                .regexMatchers("/frontend/.*", "/VAADIN/.*", "/login.*", "/accessDenied").permitAll()
                .regexMatchers(HttpMethod.POST, "/\\?v-r=.*").permitAll()
                // deny any other URL until authenticated
                .antMatchers("/**").fullyAuthenticated()
            /*
             Note that anonymous authentication is enabled by default, therefore;
             SecurityContextHolder.getContext().getAuthentication().isAuthenticated() always will return true.
             Look at LoginView.beforeEnter method.
             more info: https://docs.spring.io/spring-security/site/docs/4.0.x/reference/html/anonymous.html
             */
        ;
    }

    @Autowired
    public void configureGlobal(AuthenticationManagerBuilder auth) throws Exception {
        auth
                .inMemoryAuthentication().passwordEncoder(new BCryptPasswordEncoder())
                .withUser("admin").password("$2a$10$obstjyWMAVfsNoKisfyCjO/DNfO9OoMOKNt5a6GRlVS7XNUzYuUbO").roles("ADMIN");// user and pass: admin 
    }

    /**
    * Expose the AuthenticationManager (to be used in LoginView)
    * @return
    * @throws Exception
    */
    @Bean(name = BeanIds.AUTHENTICATION_MANAGER)
    @Override
    public AuthenticationManager authenticationManagerBean() throws Exception {
        return super.authenticationManagerBean();
    }
}

As you see, I have not specified any permission based on role on any of my routed views (annotated with @Route) yet. What I will do is if I have a routed view, I will register a BeforeEnterListener when it (the routed view) is being constructed and will check the required role/privilege there.

The following is an example to check if the user has ADMIN role before navigating to admin-utils view;

@Route(value = "admin-utils")
public class AdminUtilsView extends VerticalLayout { 
@Autowired
private HttpServletRequest req;
...
    AdminUtilsView() {
        ...
        UI.getCurrent().addBeforeEnterListener(new BeforeEnterListener() {
            @Override
            public void beforeEnter(BeforeEnterEvent beforeEnterEvent) {
                if (beforeEnterEvent.getNavigationTarget() != DeniedAccessView.class && // This is to avoid a
                        // loop if DeniedAccessView is the target
                        !req.isUserInRole("ADMIN")) {
                    beforeEnterEvent.rerouteTo(DeniedAccessView.class);
                }
            }
        });
    }
}

In case the user has not the ADMIN role, (s)he will be routed to DeniedAccessView which is permitted already for all in the Spring Security configuration.

@Route(value = "accessDenied")
public class DeniedAccessView
        extends VerticalLayout {
    DeniedAccessView() {
        FormLayout formLayout = new FormLayout();
        formLayout.add(new Label("Access denied!"));
        add(formLayout);
    }
}

In the above example (AdminUtilsView ), you can also see a use case for HttpServletRequest.isUserInRole() in Vaadin code by autowiring the HttpServletRequest.

SUMMARY: If your view has a Route, use BeforeEnterListener to Authorize the request first, otherwise use Spring Security matchers (e.g. regexMatchers or antMatchers) for rest services and etc. .

NOTE: Using both the Vaadin Route and Spring Security matcher rules together for the same rule might be a bit twisted and I don't suggest that (it causes some internal loops in Vaadin; e.g. imagine we have a view routed with /view and an entry in Spring Security for /view with a required role. If a user is missing such role and (s)he is routed/navigated to such page (using Vaadin routing API), Vaadin tries to open the view associated with the route while Spring security avoids that due to the missing role).

Also, I think, using Vaadin flow navigation API a good practice before rerouting or navigating the user to a different view/context would be to check for the required role/authority.

Moreover, to have an example of using AuthenticationManager in Vaadin, we can have a Vaadin based LoginView similar to;

@Route(value = "login")
public class LoginView
        extends FlexLayout implements BeforeEnterObserver {

    private final Label label;
    private final TextField userNameTextField;
    private final PasswordField passwordField;

    /**
    * AuthenticationManager is already exposed in WebSecurityConfig
    */
    @Autowired
    private AuthenticationManager authManager;

    @Autowired
    private HttpServletRequest req;

    LoginView() {
        label = new Label("Please login...");

        userNameTextField = new TextField();
        userNameTextField.setPlaceholder("Username");
        UiUtils.makeFirstInputTextAutoFocus(Collections.singletonList(userNameTextField));

        passwordField = new PasswordField();
        passwordField.setPlaceholder("Password");
        passwordField.addKeyDownListener(Key.ENTER, (ComponentEventListener<KeyDownEvent>) keyDownEvent -> authenticateAndNavigate());

        Button submitButton = new Button("Login");
        submitButton.addClickListener((ComponentEventListener<ClickEvent<Button>>) buttonClickEvent -> {
            authenticateAndNavigate();
        });

        FormLayout formLayout = new FormLayout();
        formLayout.add(label, userNameTextField, passwordField, submitButton);
        add(formLayout);

        // center the form
        setAlignItems(Alignment.CENTER);
        this.getElement().getStyle().set("height", "100%");
        this.getElement().getStyle().set("justify-content", "center");
    }

    private void authenticateAndNavigate() {
        /*
        Set an authenticated user in Spring Security and Spring MVC
        spring-security
        */
        UsernamePasswordAuthenticationToken authReq
                = new UsernamePasswordAuthenticationToken(userNameTextField.getValue(), passwordField.getValue());
        try {
            // Set authentication
            Authentication auth = authManager.authenticate(authReq);
            SecurityContext sc = SecurityContextHolder.getContext();
            sc.setAuthentication(auth);

            /*
            Navigate to the requested page:
            This is to redirect a user back to the originally requested URL – after they log in as we are not using
            Spring's AuthenticationSuccessHandler.
            */
            HttpSession session = req.getSession(false);
            DefaultSavedRequest savedRequest = (DefaultSavedRequest) session.getAttribute("SPRING_SECURITY_SAVED_REQUEST");
            String requestedURI = savedRequest != null ? savedRequest.getRequestURI() : Application.APP_URL;

            this.getUI().ifPresent(ui -> ui.navigate(StringUtils.removeStart(requestedURI, "/")));
        } catch (BadCredentialsException e) {
            label.setText("Invalid username or password. Please try again.");
        }
    }

    /**
    * This is to redirect user to the main URL context if (s)he has already logged in and tries to open /login
    *
    * @param beforeEnterEvent
    */
    @Override
    public void beforeEnter(BeforeEnterEvent beforeEnterEvent) {
        Authentication auth = SecurityContextHolder.getContext().getAuthentication();
        //Anonymous Authentication is enabled in our Spring Security conf
        if (auth != null && auth.isAuthenticated() && !(auth instanceof AnonymousAuthenticationToken)) {
            //https://vaadin.com/docs/flow/routing/tutorial-routing-lifecycle.html
            beforeEnterEvent.rerouteTo("");
        }
    }
}

And finally, here is the logout method that can be called from a menu or button:

/**
 * log out the current user using Spring security and Vaadin session management
 */
void requestLogout() {
    //https://stackoverflow.com/a/5727444/1572286
    SecurityContextHolder.clearContext();
    req.getSession(false).invalidate();

    // And this is similar to how logout is handled in Vaadin 8:
    // https://vaadin.com/docs/v8/framework/articles/HandlingLogout.html
    UI.getCurrent().getSession().close();
    UI.getCurrent().getPage().reload();// to redirect user to the login page
}

You can continue completing the role management using Spring UserDetailsService and creating a PasswordEncoder bean by looking at the following examples:

How to secure Vaadin flow application with Spring Security

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