Category Archives: Security

Securing Ajax endpoints inside a Web project with Spring Security

Sometime, you have to host the API inside the same project where you serve your HTML pages
Or probably a more usual case which may happen when you use JQuery with a framework like Spring MVC, the web pages are protected with a login form but you have also some URLs used by Ajax requests coming from JQuery components (such as datable) and the authentication cannot be handled in the same way.

When a user connects to the web site, he will be redirected (with a 302 http code) to the login form.
But, for example, when the user refreshes the page after the session expired, the JQuery components tries to connect through Ajax, the 302 code is returned, intercepted by the browser which follow the 302 to the login page, and then, the JQuery component receiving HTML form content in the response is not able to process it and fails with error massage.

Here the JQuery datatable code:

$('#example').DataTable( {
        "processing": true,
        "serverSide": true,
        "ajax": {
            url: "api/data/", // json datasource
            type: "get",
            error: function (jqXHR, textStatus, errorThrown) {
                if (jqXHR.status == 401) {
                    document.location.href = "login";
                } else {
                    alert("Cannot get data from server, refresh the page or call support if error persists\n: (" + JSON.stringify(jqXHR)
                        + "\ntextStatus: " + textStatus
                        + "errorThrown: " + errorThrown + ")")
                }
            }
        }
    } );

To make it behaves properly, the Ajax request should simply return a 401 code to give a chance to the JQuery component to redirect to the login page.

To implement this behaviour, Spring needs 2 security configurations:

  • One for the web pages
  • One for the URLs reached through Ajax calls

Let’s start with the security configuration for web pages, it is set in a first implementation of WebSecurityConfigurerAdapter

@Configuration
@Slf4j
@Order(100)
public class WebSecurityConfig extends WebSecurityConfigurerAdapter {

	@Override
	protected void configure(final HttpSecurity http) throws Exception {
		http
		.authorizeRequests()
		.antMatchers( "/login", "/css/**")
		.permitAll()
		.anyRequest().authenticated()
		.and()
		.formLogin()
		.and()
		.logout()
		.logoutRequestMatcher(new AntPathRequestMatcher("/logout"));
		log.info("Web security enabled");
	}
[...]
}

Here, we need to pay attention to the pages which should be publicly accessible, in my case, it means only login and css, the rest of the application must be protected.

Now, we need to take care of the API endpoints to allow the right redirection when the user session has expired (and easy way to test it is to rely on browser dev tools which often give you the opportunity to reset your session cookie).

@EnableWebSecurity
@Configuration
@Slf4j
@Order(99)
public class ApiSecurityConfig extends WebSecurityConfigurerAdapter {
	@Override
	protected void configure(final HttpSecurity http) throws Exception {
		http
		.csrf().disable()
		.requestMatchers()
		.antMatchers("/api/**")
		.and()
		.authorizeRequests()
		.anyRequest().authenticated()
		.and()
		.httpBasic();
		log.info("Api security enabled");
	}
}

The configuration of the protected url is done in a same way as before and we use basic-auth instead of form-login to send a 401 to the browser.
Something important to notice is the order annotation which makes this configuration loaded before the web security configuration to ensure that it will be executed in first. If we try to connect to “api/data” without being authenticated, we need to be sure that we will receive a 401 response and not the 302 redirection as it is the case with the web security configuration.

the code I showed can be found in this repository.

Implementing CSRF protection with Angular-js

After 2 articles on the security, I continue with the set up of the CSRF protection using Spring security.

The main idea behind is to prevent some one else to create (forge) a request without our authorization. Imagine that a page uses JavaScript to send something like https://my.bank.com/pay/15000/cayman_account, if you are connected to your bank in another tab browser, the request could be successful…
To avoid that, for each request, the server sends a unique identifier (Spring uses a UUID) and it must be part of the request you send back to the server.

Fortunately, Angular provides a support for CSRF protection. Following the documentation, the server needs to provide a cookie named XSRF-TOKEN and Angular will send its value in a header named X-XSRF-TOKEN. On the server side, Spring then verifies that the value from the header is the expected one and continue the process, otherwise, it sends an error.

But to make them working together, we need to make some adjustments.
I use the same pet store application I used in my previous article and it is still available on github.

Let’s go to the code!
First of all, on the server side, Spring provides the identifier as a request attribute, because in a standard Spring-MVC application, it is very simple to add it in an HTML form using expression language. But with our SOA approach, we are just sending data, therefore we need to put it in the cookie we send to the browser. To do that, I defined a filter which just take the CSRF token and set a cookie:

@Component
public class CsrfInjectorFilter extends OncePerRequestFilter {

	private static final String XSRF_TOKEN = "XSRF-TOKEN";
	private static final Logger LOG = LoggerFactory.getLogger(CsrfInjectorFilter.class);

	@Override
	protected void doFilterInternal(HttpServletRequest request, HttpServletResponse response, FilterChain chain)
			throws ServletException, IOException {

		CsrfToken csrfToken = (CsrfToken) request.getAttribute(CsrfToken.class.getName());
		if (csrfToken != null) {
			Cookie cookie = new Cookie(XSRF_TOKEN, csrfToken.getToken());
			//mandatory to avoid duplicate cookies in browser
			cookie.setPath("/");
			response.addCookie(cookie);
		}else {
			LOG.debug("No csrf token found!!");
		}
		chain.doFilter(request, response);
	}
}

Note: I choose to define the cookie name as Angular expects it, but it also possible to define its name on the client side (using $httpProvider.defaults.xsrfCookieName) and keeping the web service ignore who is the client.

There is also one important thing you must absolutely do (I spent half of a day with that!), you have to set a path to your cookie! Otherwise, for some reasons, the browser does not replace the cookie when it is changed, and it simply manage several cookies with the same name, resulting in CSRF errors on the server side. I tested this issue with Firefox and Chrome.
On the other side, I need to configure Angular to return the header as expected by Spring, this is done in the app.js file:

petstoreApp.config(['$httpProvider', function($httpProvider){
    $httpProvider.defaults.xsrfHeaderName = 'X-CSRF-TOKEN';
}]);

We can see that the code is very straightforward.

Angular-js and Restful web services access

Following my previous article about the integration of Spring Security with web services, I will now explain how I integrate it with an Angular-js project.
For that purpose, I am a little bit lazy and I use a project I already written instead of building a completely new one.

The project is a “funny” pet-store based on Spring boot (I like it definitely!), using an H2 database and Flyway to restore its content at each start.
The full project is available on Github.

The web services are defined with Spring MVC in the net.classnotfound.pet.web.PetController:

package net.classnotfound.pet.web;
...
@RestController
public class PetController {
	
	@Autowired
	private PetService petService;
	
	@RequestMapping(value = "/pet/all", method = RequestMethod.GET)
	@ResponseBody
	public Collection<JsonPet> findAll() {
		...
	}
	
	@Transactional(propagation= Propagation.SUPPORTS)
	@RequestMapping(value = "/pet/{id}", method = RequestMethod.GET)
	@ResponseBody
	public JsonPet find(@PathVariable("id") final Integer id) {
		...
	}

	@Transactional(propagation= Propagation.REQUIRED)
	@RequestMapping(value = "/pet", method = RequestMethod.POST, consumes = {"application/json" })
	@ResponseStatus(HttpStatus.CREATED)
	public @ResponseBody JsonPet save(@RequestBody final JsonPet jsonPet) {
		...
	}
}

The PetService is the class responsible of business processes (mainly access data here).

We can see that there are 3 actions available to:

  • display the list of pets in the store
  • display the detail of a pet
  • create a “new” pet in the store

The attributes of the requestMapping annotation seem explicit, for example, with @RequestMapping(value = “/pet”, method = RequestMethod.POST, consumes = {“application/json” }), I express that the method can be reach with /pet URL, by using the POST method and it needs json.
Based on Spring, the conversion from Json to Java Object (and the opposite) is totally hidden (it relies on Jackson API) and it avoid this burden to the developer (meaning me, here!).

Now that the landscape is set, let’s have a look at the security configuration (it should be familiar to whose who read my previous article):

@Override
protected void configure(AuthenticationManagerBuilder auth) throws Exception {
	auth.inMemoryAuthentication().
	  withUser("admin").password("password").roles("ADMIN", "USER").and().
	  withUser("user").password("password").roles("USER");
}

@Override
protected void configure(HttpSecurity http) throws Exception { 
	
	http
	.csrf().disable()
	.authorizeRequests()
	.antMatchers("/login").anonymous()
	.antMatchers(HttpMethod.GET, "/pet/**").access("hasRole('USER')")
	.antMatchers(HttpMethod.POST, "/pet/**").access("hasRole('ADMIN')");
	
	http.exceptionHandling().authenticationEntryPoint(authenticationEntryPoint);
	FormLoginConfigurer formLogin = http.formLogin();
	formLogin.loginProcessingUrl("/login");
	formLogin.usernameParameter("username");
	formLogin.passwordParameter("password");
	formLogin.successHandler(authenticationSuccessHandler);
	formLogin.failureHandler(authenticationFailureHandler);
	
}

I started with the users definition with their roles.
And after that, Y can see how I restricted access to the features, as previously, I disabled the CSRF protection but I will come back to it in a next article.

Now, if a unauthenticated user tries to access the protected resources, he will receive an HTTP 401 error. Let’s see how I deal with it on the client side (Angular-js).
The web pages are located in

The idea is to have the generic process to intercept the right HTTP code when the user needs to be authenticated, and redirect him automatically to the login page .
The application is based on the single page principle, for that purpose, I use the ngRoute module, it is configured in the app.js file:

petstoreApp.config(['$routeProvider',
  function($routeProvider) {
    $routeProvider.
      when('/pets', {
	      templateUrl: 'partials/pet-list.html',
	      controller: 'PetListCtrl'
      }).
      when('/pets/new', {
    	  templateUrl: 'partials/pet-new.html',
    	  controller: 'PetNewCtrl'
      }).
      when('/pets/:petId', {
          templateUrl: 'partials/pet-detail.html',
          controller: 'PetDetailCtrl'
      }).
      when('/login', {
          templateUrl: 'partials/login.html',
          controller: 'LoginCtrl'
        }).
      otherwise({
        redirectTo: '/pets'
      });
  }]);

As expected, we can find our 3 pages related to the web services features and another one to ask credentials to users. This one will be used when redirecting unauthenticated users.
For that purpose, the application is configured with an Angular-js interceptor. All the requests sent or received can be manipulated by interceptor, this is very useful for common purposes like error management or authentication, and it is exactly the way I use it (still in the app.js file):

petstoreApp.factory('errorInterceptor', ['$q', '$location', '$window', '$injector', function($q, $location, $window, $injector) {
	var authSrv;
	var popupSrv;
	var errorInterceptor = {
			'responseError' : function(rejection) {
				var status = rejection.status;
				if (rejection.data){
					if (status == 401) {//Unauthenticated, redirect to login page
						$window.location.href="/#/login";
						return;
					} else if (status == 418) {//undefined error->HTTP code 418 ( I'm a teapot) is responsibility of the caller
						return $q.reject(rejection);
					} else{
						popupSrv = popupSrv || $injector.get('popUpSrv');
						popupSrv.alert("Erreur: "+rejection.data.message+ (rejection.data.stackTrace?"\r\n___________________________________\r\n\r\nErreur complète:\r\n" + rejection.data.stackTrace:''));
						return;
					} 
				} else {
					popupSrv = popupSrv || $injector.get('popUpSrv');
					popupSrv.alert("Erreur inconnue( http status: "+status+")");
					return;
				}
				return $q.reject(rejection);
			}};
	return errorInterceptor;
}]);
petstoreApp.config(['$httpProvider', function($httpProvider) {  
    $httpProvider.interceptors.push('errorInterceptor');
}]);

The interceptor is in charge of managing the HTTP 401 code by redirecting to the login form, and also of the display of a generic message error.
For more information about interceptors and their usage, you can directly have a look at the official site.

And now, it works! The web site can access resources protected with Spring security. In the real world, I should display the new pet button only for admin users, it means that I should also provide a service indicate which actions are available for a user.

For those who missed the point, the sources of the project are available here.

Securing Restful web services using Spring-Security

After several months of silent, I woke up… With some security interests!
The security is a common requirement on many web projects, and fortunately, Spring helps us to implement it.
The most common way to do it is just defining a set of rules and letting Spring manage the login and so on.
In this demo, I will use Spring-boot (for its simplicity) but the security configuration is exactly the same with a web application.
And to be clear, I do not have the pretentiousness that this is THE way to follow when you need to secure your web services and I am convinced that someone else found another way to do it, but this is my solution, I used it several times, and it works perfectly, so maybe it will help someone else… One day 🙂

To start simply, I just built a simple web site with 2 pages:

  • the home page (/index.html), which is freely accessible
  • and another page (/secured/page.html) which is in a restricted area

Using Spring-boot, the structure is something like:

structure

By default, Spring boot published everything under the static directory and is accessible via http://localhost:8080/

For instance, everybody can access to our pages, it’s time to remedy to that state.

Let’s start with the interesting part of the Maven Configuration:

<parent>
	<groupId>org.springframework.boot</groupId>
	<artifactId>spring-boot-starter-parent</artifactId>
	<version>1.3.2.RELEASE</version>
	<relativePath/> <!-- lookup parent from repository -->
</parent>

<properties>
	<project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
	<java.version>1.8</java.version>
</properties>

<dependencies>
	<dependency>
		<groupId>org.springframework.boot</groupId>
		<artifactId>spring-boot-starter-security</artifactId>
	</dependency>
	<dependency>
		<groupId>org.springframework.boot</groupId>
		<artifactId>spring-boot-starter-web</artifactId>
	</dependency>
	
	<dependency>
		<groupId>org.springframework.boot</groupId>
		<artifactId>spring-boot-starter-test</artifactId>
		<scope>test</scope>
	</dependency>
</dependencies>

<build>
	<plugins>
		<plugin>
			<groupId>org.springframework.boot</groupId>
			<artifactId>spring-boot-maven-plugin</artifactId>
		</plugin>
	</plugins>
</build>

The starter dependencies are somehow facilitators provided by Spring boot to add some dependencies, I think that we can guess their purpose just by their name. For more information about this pom, you can have a look to the Spring-boot site.

Now, we have to restrict access to the secured part of the site, this is done here:

@Configuration
@EnableWebSecurity
public class SecurityJavaConfig extends WebSecurityConfigurerAdapter {
    @Override
    protected void configure(AuthenticationManagerBuilder auth) throws Exception {
        auth.inMemoryAuthentication().
          withUser("admin").password("password").roles("ADMIN", "USER").and().
          withUser("user").password("password").roles("USER");
    }
 
    @Override
    protected void configure(HttpSecurity http) throws Exception { 
        http
        .authorizeRequests()
        .antMatchers(HttpMethod.GET, "/secured/**").access("hasRole('USER')");
        
        //indicate that we are user login form authentication
        http.formLogin();
    }
}

For the demo, I define my users directly in the application, this is AuthenticationManagerBuilder.inMemoryAuthentication().

Inside the configure(HttpSecurity http) method, you can see that I just defined the URL of the secured part, indicating who can access it based on role.
And finally, I indicate that I want to use the form login authentication as it is provided by Spring.

According to the configuration, the users can access freely the home page, but only the users authenticated and with the right role can access to the secured part. This is a perfect configuration for a standard web site, but remember that we nee to secure a web service, the redirection to a login form is not an acceptable way for that purpose and we need to customise this behavior.

The first issue to solve is to avoid to redirection to the login form in case of unauthenticated access, I do it by changing the AuthenticationEntryPoint with mine:

@Component
public class RestAuthenticationEntryPoint implements AuthenticationEntryPoint {
	@Override
	public void commence(HttpServletRequest request, HttpServletResponse response, AuthenticationException authException)
			throws IOException, ServletException {
		response.sendError(HttpServletResponse.SC_UNAUTHORIZED);
	}
}

As you can see, this is very simple, I just need to send the right HTTP code to inform my client that it needs to authenticate before accessing the resource it requested.
And to indicate to Spring that I slightly changed the authentication, it is very complicated because… Well, it’s Spring, so, I just need to add the following in my SecurityJavaConfig:

[...]
@Autowired
private AuthenticationEntryPoint authenticationEntryPoint;
[...]
protected void configure(HttpSecurity http) throws Exception {
	http.exceptionHandling().authenticationEntryPoint(authenticationEntryPoint);
}

Now, when someone… As we are dealing with web services,I should say something tries to access to secured resources, it just receives an unauthorized HTTP code instead of a redirection to the login page.
That’s a good point but we have also to manage the successful and erroneous authentication. Instead of redirecting to a page, we have to inform the client that the credentials are valid or not .
For each case, we need to define two different classes:

  • in case of success, we let Spring clean-up the temporary data:
    @Component
    public class RestAuthenticationSuccessHandler extends SimpleUrlAuthenticationSuccessHandler {
    	@Override
    	public void onAuthenticationSuccess(HttpServletRequest request, HttpServletResponse response,
    			Authentication authentication) throws IOException, ServletException {
    		clearAuthenticationAttributes(request);
    	}
    }
    
  • in case of error, we return an HTTP code and an optional message:
    @Component
    public class RestAuthenticationFailureHandler implements AuthenticationFailureHandler{
    	@Override
    	public void onAuthenticationFailure(HttpServletRequest arg0, HttpServletResponse arg1, AuthenticationException arg2)
    			throws IOException, ServletException {
    		arg1.sendError(HttpServletResponse.SC_FORBIDDEN, "Wrong username or password");
    	}
    }
    
  • And then the last step is to add them to the Spring configuration:

    [...]
    @Autowired
    private AuthenticationFailureHandler authenticationFailureHandler;
    
    @Autowired
    private AuthenticationSuccessHandler authenticationSuccessHandler;
    [...]
    protected void configure(HttpSecurity http) throws Exception {
    	[...]
    	FormLoginConfigurer formLogin = http.formLogin();
    	[...]
    	formLogin.successHandler(authenticationSuccessHandler);
    	formLogin.failureHandler(authenticationFailureHandler);
    
    }
    

    Now, we can define our web services, and Spring will manage authentication for us.
    To protect your services, obviously, you need to add something like:

    http
    .authorizeRequests()
    [...]
    .antMatchers(HttpMethod.GET, "/secured/services/**")
    .access("hasRole('SERVICE_USER')");
    

    And you can also restrict access by the HTTP methods, someone can read data (GET method) but could not be allowed to modify it (POST/PUT methods).
    That’s it!

    In a next post, I will show how I used it with Angular-js, stay tuned 😀

    (the full project is available on Github)