The j2e-pac4j project is an easy and powerful security library for J2E web applications which supports authentication and authorization, but also logout and advanced features like session fixation and CSRF protection. It's based on Java 8, servlet 3 and on the pac4j security engine v2.0. It's available under the Apache 2 license.

Main concepts and components:

1. A client represents an authentication mechanism. It performs the login process and returns a user profile. An indirect client is for UI authentication while a direct client is for web services authentication:

▸ OAuth - SAML - CAS - OpenID Connect - HTTP - OpenID - Google App Engine - LDAP - SQL - JWT - MongoDB - Stormpath - IP address

2. An authorizer is meant to check authorizations on the authenticated user profile(s) or on the current web context:

▸ Roles / permissions - Anonymous / remember-me / (fully) authenticated - Profile type, attribute - CORS - CSRF - Security headers - IP address, HTTP method

3. The SecurityFilter protects an url by checking that the user is authenticated and that the authorizations are valid, according to the clients and authorizers configuration. If the user is not authenticated, it performs authentication for direct clients or starts the login process for indirect clients

4. The CallbackFilter finishes the login process for an indirect client

5. The LogoutFilter handles the logout process.

==

Just follow these easy steps to secure your J2E web application:

You need to add a dependency on:

• the j2e-pac4j library (groupId: org.pac4j, version: 2.0.0-RC2)
• the appropriate pac4j submodules (groupId: org.pac4j, version: 2.0.0-RC2): pac4j-oauth for OAuth support (Facebook, Twitter...), pac4j-cas for CAS support, pac4j-ldap for LDAP authentication, etc.

All released artifacts are available in the Maven central repository.

The configuration (org.pac4j.core.config.Config) contains all the clients and authorizers required by the application to handle security.

It must be built via a configuration factory (org.pac4j.core.config.ConfigFactory):

public class DemoConfigFactory implements ConfigFactory {

    @Override
    public Config build() {
        final OidcConfiguration oidcConfiguration = new OidcConfiguration();
        oidcConfiguration.setClientId("167480702619-8e1lo80dnu8bpk3k0lvvj27noin97vu9.apps.googleusercontent.com");
        oidcConfiguration.setSecret("MhMme_Ik6IH2JMnAT6MFIfee");
        oidcConfiguration.setUseNonce(true);
        oidcConfiguration.addCustomParam("prompt", "consent");
        final GoogleOidcClient oidcClient = new GoogleOidcClient(oidcConfiguration);
        oidcClient.setAuthorizationGenerator((ctx, profile) -> { profile.addRole("ROLE_ADMIN"); return profile; });

        final SAML2ClientConfiguration cfg = new SAML2ClientConfiguration("resource:samlKeystore.jks", "pac4j-demo-passwd", "pac4j-demo-passwd", "resource:testshib-providers.xml");
        cfg.setMaximumAuthenticationLifetime(3600);
        cfg.setServiceProviderEntityId("http://localhost:8080/callback?client_name=SAML2Client");
        cfg.setServiceProviderMetadataPath(new File("sp-metadata.xml").getAbsolutePath());
        final SAML2Client saml2Client = new SAML2Client(cfg);

        final FacebookClient facebookClient = new FacebookClient("145278422258960", "be21409ba8f39b5dae2a7de525484da8");
        final TwitterClient twitterClient = new TwitterClient("CoxUiYwQOSFDReZYdjigBA", "2kAzunH5Btc4gRSaMr7D7MkyoJ5u1VzbOOzE8rBofs");
        final FormClient formClient = new FormClient("http://localhost:8080/loginForm.jsp", new SimpleTestUsernamePasswordAuthenticator());
        final IndirectBasicAuthClient indirectBasicAuthClient = new IndirectBasicAuthClient(new SimpleTestUsernamePasswordAuthenticator());

        final CasConfiguration configuration = new CasConfiguration("http://localhost:8888/cas/login");
        final CasProxyReceptor casProxy = new CasProxyReceptor();
        configuration.setProxyReceptor(casProxy);
        final CasClient casClient = new CasClient(configuration);

        final List<SignatureConfiguration> signatures = new ArrayList<>();
        signatures.add(new SecretSignatureConfiguration(Constants.JWT_SALT));
        ParameterClient parameterClient = new ParameterClient("token", new JwtAuthenticator(signatures));
        parameterClient.setSupportGetRequest(true);
        parameterClient.setSupportPostRequest(false);

        final DirectBasicAuthClient directBasicAuthClient = new DirectBasicAuthClient(new SimpleTestUsernamePasswordAuthenticator());

        final Clients clients = new Clients("http://localhost:8080/callback", oidcClient, saml2Client, facebookClient,
                twitterClient, formClient, indirectBasicAuthClient, casClient, parameterClient,
                directBasicAuthClient, new AnonymousClient(), casProxy);

        final Config config = new Config(clients);
        config.addAuthorizer("admin", new RequireAnyRoleAuthorizer<>("ROLE_ADMIN"));
        config.addAuthorizer("custom", new CustomAuthorizer());
        config.addAuthorizer("mustBeAnon", new IsAnonymousAuthorizer<>("/?mustBeAnon"));
        config.addAuthorizer("mustBeAuth", new IsAuthenticatedAuthorizer<>("/?mustBeAuth"));
        config.addMatcher("excludedPath", new PathMatcher().excludeRegex("^/facebook/notprotected\\.jsp$"));
        return config;
    }
}

http://localhost:8080/callback is the url of the callback endpoint, which is only necessary for indirect clients.

Notice that you can define specific matchers via the addMatcher(name, Matcher) method.

If your application is configured via dependency injection, no factory is required to build the configuration, you can directly inject the Config via the appropriate setter.

You can protect (authentication + authorizations) the urls of your J2E application by using the SecurityFilter and defining the appropriate mapping. It has the following behaviour:

1. If the HTTP request matches the matchers configuration (or no matchers are defined), the security is applied. Otherwise, the user is automatically granted access.

2. First, if the user is not authenticated (no profile) and if some clients have been defined in the clients parameter, a login is tried for the direct clients.

3. Then, if the user has a profile, authorizations are checked according to the authorizers configuration. If the authorizations are valid, the user is granted access. Otherwise, a 403 error page is displayed.

4. Finally, if the user is still not authenticated (no profile), he is redirected to the appropriate identity provider if the first defined client is an indirect one in the clients configuration. Otherwise, a 401 error page is displayed.

The following parameters are available:

1. configFactory: the factory to initialize the configuration. By default, the configuration is shared across filters so it can be specified only once, but each filter can defined its own configuration if necessary

2. clients (optional): the list of client names (separated by commas) used for authentication:

• in all cases, this filter requires the user to be authenticated. Thus, if the clients is blank or not defined, the user must have been previously authenticated
• if the client_name request parameter is provided, only this client (if it exists in the clients) is selected.

3. authorizers (optional): the list of authorizer names (separated by commas) used to check authorizations:

• if the authorizers is blank or not defined, no authorization is checked
• the following authorizers are available by default (without defining them in the configuration):
  • isFullyAuthenticated to check if the user is authenticated but not remembered, isRemembered for a remembered user, isAnonymous to ensure the user is not authenticated, isAuthenticated to ensure the user is authenticated (not necessary by default unless you use the AnonymousClient)
  • hsts to use the StrictTransportSecurityHeader authorizer, nosniff for XContentTypeOptionsHeader, noframe for XFrameOptionsHeader , xssprotection for XSSProtectionHeader , nocache for CacheControlHeader or securityHeaders for the five previous authorizers
  • csrfToken to use the CsrfTokenGeneratorAuthorizer with the DefaultCsrfTokenGenerator (it generates a CSRF token and saves it as the pac4jCsrfToken request attribute and in the pac4jCsrfToken cookie), csrfCheck to check that this previous token has been sent as the pac4jCsrfToken header or parameter in a POST request and csrf to use both previous authorizers.

4. matchers (optional): the list of matcher names (separated by commas) that the request must satisfy to check authentication / authorizations

5. multiProfile (optional): it indicates whether multiple authentications (and thus multiple profiles) must be kept at the same time (false by default).

In the web.xml file:

<filter>
  <filter-name>FacebookAdminFilter</filter-name>
  <filter-class>org.pac4j.j2e.filter.SecurityFilter</filter-class>
  <init-param>
    <param-name>configFactory</param-name>
    <param-value>org.pac4j.demo.j2e.DemoConfigFactory</param-value>
  </init-param>
  <init-param>
    <param-name>clients</param-name>
    <param-value>FacebookClient</param-value>
  </init-param>
</filter>
<filter-mapping>
  <filter-name>FacebookAdminFilter</filter-name>
  <url-pattern>/facebook/*</url-pattern>
</filter-mapping>

This filter can be defined via dependency injection as well. In that case, these parameters will be defined via setters.

For indirect clients (like Facebook), the user is redirected to an external identity provider for login and then back to the application. Thus, a callback endpoint is required in the application. It is managed by the CallbackFilter which has the following behaviour:

1. the credentials are extracted from the current request to fetch the user profile (from the identity provider) which is then saved in the web session

2. finally, the user is redirected back to the originally requested url (or to the defaultUrl).

The following parameters are available:

1. configFactory (optional): the factory to initialize the configuration. By default, the configuration is shared across filters so it can be specified only once, but each filter can defined its own configuration if necessary

2. defaultUrl (optional): it's the default url after login if no url was originally requested (/ by default)

3. multiProfile (optional): it indicates whether multiple authentications (and thus multiple profiles) must be kept at the same time (false by default)

4. renewSession (optional): it indicates whether the web session must be renewed after login, to avoid session hijacking (true by default).

In the web.xml file:

<filter>
  <filter-name>callbackFilter</filter-name>
  <filter-class>org.pac4j.j2e.filter.CallbackFilter</filter-class>
  <init-param>
    <param-name>defaultUrl</param-name>
    <param-value>/</param-value>
  </init-param>
</filter>
<filter-mapping>
  <filter-name>callbackFilter</filter-name>
  <url-pattern>/callback</url-pattern>
</filter-mapping>

Using dependency injection via Spring, you can define the callback filter as a DelegatingFilterProxy in the web.xml file:

<filter>
  <filter-name>callbackFilter</filter-name>
  <filter-class>org.springframework.web.filter.DelegatingFilterProxy</filter-class>
</filter>
<filter-mapping>
  <filter-name>callbackFilter</filter-name>
  <url-pattern>/callback</url-pattern>
</filter-mapping>

and the specific bean in the application-context.xml file:

<bean id="callbackFilter" class="org.pac4j.j2e.filter.CallbackFilter">
  <property name="defaultUrl" value="/" />
</bean>

You can get the profile of the authenticated user using profileManager.get(true) (false not to use the session, but only the current HTTP request). You can test if the user is authenticated using profileManager.isAuthenticated(). You can get all the profiles of the authenticated user (if ever multiple ones are kept) using profileManager.getAll(true).

Example:

WebContext context = new J2EContext(request, response);
ProfileManager manager = new ProfileManager(context);
Optional<CommonProfile> profile = manager.get(true);

The retrieved profile is at least a CommonProfile, from which you can retrieve the most common attributes that all profiles share. But you can also cast the user profile to the appropriate profile according to the provider used for authentication. For example, after a Facebook authentication:

FacebookProfile facebookProfile = (FacebookProfile) commonProfile;

The LogoutFilter can handle:

• the local logout by removing the pac4j profiles from the session (it can be used for the front-channel logout from the identity provider in case of a central logout)
• the central logout by calling the identity provider logout endpoint.

It has the following behaviour:

1. If the localLogout property is true, the pac4j profiles are removed from the web session (and the web session is destroyed if the destroySession property is true)

2. A post logout action is computed as the redirection to the url request parameter if it matches the logoutUrlPattern or to the defaultUrl if it is defined or as a blank page otherwise

3. If the centralLogout property is true, the user is redirected to the identity provider for a central logout and then optionally to the post logout redirection URL (if it's supported by the identity provider and if it's an absolute URL). If no central logout is defined, the post logout action is performed directly.

The following parameters are available:

1. defaultUrl (optional): the default logout url if no url request parameter is provided or if the url does not match the logoutUrlPattern (not defined by default)

2. logoutUrlPattern (optional): the logout url pattern that the url parameter must match (only relative urls are allowed by default)

3. localLogout (optional): whether a local logout must be performed (true by default)

4. destroySession (optional): whether we must destroy the web session during the local logout (false by default)

5. centralLogout (optional): whether a central logout must be performed (false by default).

In the web.xml file:

<filter>
  <filter-name>logoutFilter</filter-name>
  <filter-class>org.pac4j.j2e.filter.LogoutFilter</filter-class>
  <init-param>
    <param-name>defaultUrl</param-name>
    <param-value>/urlAfterLogout</param-value>
  </init-param>
</filter>
<filter-mapping>
  <filter-name>logoutFilter</filter-name>
  <url-pattern>/logout</url-pattern>
</filter-mapping>

The ApplicationLogoutFilter has been renamed as LogoutFilter and now handles both the application and identity provider logouts.

The RequiresAuthenticationFilter is now named SecurityFilter with the clients, authorizers and matchers parameters instead of the previous clientName, authorizerName and matcherName.

The ApplicationLogoutFilter behaviour has slightly changed: even without any url request parameter, the user will be redirected to the defaultUrl if it has been defined.

Authorizations are now handled by the library so the ClientFactory can now longer be used and is replaced by a ConfigFactory which builds a Config which gathers clients (for authentication) and authorizers (for authorizations).

The isAjax parameter is no longer available as AJAX requests are now automatically detected. The stateless parameter is no longer available as the stateless nature is held by the client itself.

The requireAnyRole and requieAllRoles parameters are no longer available and authorizers must be used instead (with the authorizerName parameter).

The application logout process can be managed with the ApplicationLogoutFilter.

The demo webapp: j2e-pac4j-demo is available for tests and implements many authentication mechanisms: Facebook, Twitter, form, basic auth, CAS, SAML, OpenID Connect, JWT...

See the release notes. Learn more by browsing the j2e-pac4j Javadoc and the pac4j Javadoc.

If you have any question, please use the following mailing lists:

• pac4j users
• pac4j developers

The version 2.0.0-RC3-SNAPSHOT is under development.

Maven artifacts are built via Travis: and available in the Sonatype snapshots repository. This repository must be added in the Maven pom.xml file for example:

<repositories>
  <repository>
    <id>sonatype-nexus-snapshots</id>
    <name>Sonatype Nexus Snapshots</name>
    <url>https://oss.sonatype.org/content/repositories/snapshots</url>
    <releases>
      <enabled>false</enabled>
    </releases>
    <snapshots>
      <enabled>true</enabled>
    </snapshots>
  </repository>
</repositories>