Introduzione a Spring Method Security

1. Introduzione

In poche parole, Spring Security supporta la semantica di autorizzazione a livello di metodo.

In genere, potremmo proteggere il nostro livello di servizio, ad esempio, limitando i ruoli in grado di eseguire un particolare metodo e testarlo utilizzando il supporto di test di sicurezza a livello di metodo dedicato.

In questo articolo, esamineremo prima l'uso di alcune annotazioni di sicurezza. Quindi, ci concentreremo sul test della sicurezza del nostro metodo con strategie diverse.

2. Abilitazione della protezione del metodo

Prima di tutto, per utilizzare Spring Method Security, dobbiamo aggiungere la dipendenza spring-security-config :

 org.springframework.security spring-security-config 

Possiamo trovare la sua ultima versione su Maven Central.

Se vogliamo usare Spring Boot, possiamo usare la dipendenza spring-boot-starter-security che include spring-security-config :

 org.springframework.boot spring-boot-starter-security 

Ancora una volta, l'ultima versione può essere trovata su Maven Central.

Successivamente, dobbiamo abilitare la sicurezza del metodo globale:

@Configuration @EnableGlobalMethodSecurity( prePostEnabled = true, securedEnabled = true, jsr250Enabled = true) public class MethodSecurityConfig extends GlobalMethodSecurityConfiguration { }
  • La proprietà prePostEnabled abilita le annotazioni pre / post di Spring Security
  • La proprietà securedEnabled determina se l' annotazione @Secured deve essere abilitata
  • La proprietà jsr250Enabled ci consente di utilizzare l' annotazione @RoleAllowed

Esploreremo di più su queste annotazioni nella sezione successiva.

3. Applicazione della protezione del metodo

3.1. Utilizzando @Secured Annotazione

L' annotazione @Secured viene utilizzata per specificare un elenco di ruoli su un metodo. Quindi, un utente può accedere a quel metodo solo se ha almeno uno dei ruoli specificati.

Definiamo un metodo getUsername :

@Secured("ROLE_VIEWER") public String getUsername() { SecurityContext securityContext = SecurityContextHolder.getContext(); return securityContext.getAuthentication().getName(); }

Qui, l' annotazione @Secured (“ROLE_VIEWER”) definisce che solo gli utenti che hanno il ruolo ROLE_VIEWER possono eseguire il metodo getUsername .

Inoltre, possiamo definire un elenco di ruoli in un'annotazione @Secured :

@Secured({ "ROLE_VIEWER", "ROLE_EDITOR" }) public boolean isValidUsername(String username) { return userRoleRepository.isValidUsername(username); }

In questo caso, la configurazione afferma che se un utente ha ROLE_VIEWER o ROLE_EDITOR , quell'utente può richiamare il metodo isValidUsername .

L' annotazione @Secured non supporta Spring Expression Language (SpEL).

3.2. Utilizzo di @RoleAllowed Annotation

Il @RoleAllowed annotazione è l'annotazione equivalente JSR-250 di del @Secured annotazioni .

Fondamentalmente, possiamo usare l' annotazione @RoleAllowed in modo simile a @Secured . Quindi, potremmo ridefinire i metodi getUsername e isValidUsername :

@RolesAllowed("ROLE_VIEWER") public String getUsername2() { //... } @RolesAllowed({ "ROLE_VIEWER", "ROLE_EDITOR" }) public boolean isValidUsername2(String username) { //... }

Allo stesso modo, solo l'utente che ha il ruolo ROLE_VIEWER può eseguire getUsername2 .

Di nuovo, un utente è in grado di richiamare isValidUsername2 solo se ha almeno uno dei ruoli ROLE_VIEWER o ROLER_EDITOR .

3.3. Utilizzo delle annotazioni @PreAuthorize e @PostAuthorize

Entrambe le annotazioni @PreAuthorize e @PostAuthorize forniscono un controllo dell'accesso basato su espressioni. Quindi, i predicati possono essere scritti utilizzando SpEL (Spring Expression Language).

L' annotazione @PreAuthorize controlla l'espressione data prima di entrare nel metodo , mentre l' annotazione @PostAuthorize la verifica dopo l'esecuzione del metodo e potrebbe alterare il risultato .

Ora, dichiariamo un metodo getUsernameInUpperCase come di seguito:

@PreAuthorize("hasRole('ROLE_VIEWER')") public String getUsernameInUpperCase() { return getUsername().toUpperCase(); }

Il @PreAuthorize ( “hasRole ( 'ROLE_VIEWER')”) ha lo stesso significato come @Secured ( “ROLE_VIEWER”) che abbiamo usato nella sezione precedente. Sentiti libero di scoprire ulteriori dettagli sulle espressioni di sicurezza negli articoli precedenti.

Di conseguenza, l'annotazione @Secured ({"ROLE_VIEWER", "ROLE_EDITOR"}) può essere sostituita con @PreAuthorize ("hasRole ('ROLE_VIEWER') o hasRole ('ROLE_EDITOR')"):

@PreAuthorize("hasRole('ROLE_VIEWER') or hasRole('ROLE_EDITOR')") public boolean isValidUsername3(String username) { //... }

Inoltre, possiamo effettivamente utilizzare l'argomento del metodo come parte dell'espressione :

@PreAuthorize("#username == authentication.principal.username") public String getMyRoles(String username) { //... }

Qui, un utente può richiamare il metodo getMyRoles solo se il valore dell'argomento nomeutente è lo stesso del nome utente dell'entità corrente.

Vale la pena notare che le espressioni @PreAuthorize possono essere sostituite da quelle @PostAuthorize .

Riscrittura di Let getMyRoles :

@PostAuthorize("#username == authentication.principal.username") public String getMyRoles2(String username) { //... }

Nell'esempio precedente, tuttavia, l'autorizzazione veniva ritardata dopo l'esecuzione del metodo di destinazione.

Inoltre, l' annotazione @PostAuthorize fornisce la possibilità di accedere al risultato del metodo :

@PostAuthorize ("returnObject.username == authentication.principal.nickName") public CustomUser loadUserDetail(String username) { return userRoleRepository.loadUserByUserName(username); }

In this example, the loadUserDetail method would only execute successfully if the username of the returned CustomUser is equal to the current authentication principal's nickname.

In this section, we mostly use simple Spring expressions. For more complex scenarios, we could create custom security expressions.

3.4. Using @PreFilter and @PostFilter Annotations

Spring Security provides the @PreFilter annotation to filter a collection argument before executing the method:

@PreFilter("filterObject != authentication.principal.username") public String joinUsernames(List usernames) { return usernames.stream().collect(Collectors.joining(";")); }

In this example, we're joining all usernames except for the one who is authenticated.

Here, in our expression, we use the name filterObject to represent the current object in the collection.

However, if the method has more than one argument which is a collection type, we need to use the filterTarget property to specify which argument we want to filter:

@PreFilter (value = "filterObject != authentication.principal.username", filterTarget = "usernames") public String joinUsernamesAndRoles( List usernames, List roles) { return usernames.stream().collect(Collectors.joining(";")) + ":" + roles.stream().collect(Collectors.joining(";")); }

Additionally, we can also filter the returned collection of a method by using @PostFilter annotation:

@PostFilter("filterObject != authentication.principal.username") public List getAllUsernamesExceptCurrent() { return userRoleRepository.getAllUsernames(); }

In this case, the name filterObject refers to the current object in the returned collection.

With that configuration, Spring Security will iterate through the returned list and remove any value matching the principal's username.

Spring Security – @PreFilter and @PostFilter article describes both annotations in greater detail.

3.5. Method Security Meta-Annotation

We typically find ourselves in a situation where we protect different methods using the same security configuration.

In this case, we can define a security meta-annotation:

@Target(ElementType.METHOD) @Retention(RetentionPolicy.RUNTIME) @PreAuthorize("hasRole('VIEWER')") public @interface IsViewer { }

Next, we can directly use the @IsViewer annotation to secure our method:

@IsViewer public String getUsername4() { //... }

Security meta-annotations are a great idea because they add more semantics and decouple our business logic from the security framework.

3.6. Security Annotation at the Class Level

If we find ourselves using the same security annotation for every method within one class, we can consider putting that annotation at class level:

@Service @PreAuthorize("hasRole('ROLE_ADMIN')") public class SystemService { public String getSystemYear(){ //... } public String getSystemDate(){ //... } }

In above example, the security rule hasRole(‘ROLE_ADMIN') will be applied to both getSystemYear and getSystemDate methods.

3.7. Multiple Security Annotations on a Method

We can also use multiple security annotations on one method:

@PreAuthorize("#username == authentication.principal.username") @PostAuthorize("returnObject.username == authentication.principal.nickName") public CustomUser securedLoadUserDetail(String username) { return userRoleRepository.loadUserByUserName(username); }

Hence, Spring will verify authorization both before and after the execution of the securedLoadUserDetail method.

4. Important Considerations

There are two points we'd like to remind regarding method security:

  • By default, Spring AOP proxying is used to apply method security – if a secured method A is called by another method within the same class, security in A is ignored altogether. This means method A will execute without any security checking. The same applies to private methods
  • Spring SecurityContext is thread-bound – by default, the security context isn't propagated to child-threads. For more information, we can refer to Spring Security Context Propagation article

5. Testing Method Security

5.1. Configuration

To test Spring Security with JUnit, we need the spring-security-test dependency:

 org.springframework.security spring-security-test 

We don't need to specify the dependency version because we're using the Spring Boot plugin. We can find the latest version of this dependency on Maven Central.

Next, let's configure a simple Spring Integration test by specifying the runner and the ApplicationContext configuration:

@RunWith(SpringRunner.class) @ContextConfiguration public class MethodSecurityIntegrationTest { // ... }

5.2. Testing Username and Roles

Now that our configuration is ready, let's try to test our getUsername method which we secured with the @Secured(“ROLE_VIEWER”) annotation:

@Secured("ROLE_VIEWER") public String getUsername() { SecurityContext securityContext = SecurityContextHolder.getContext(); return securityContext.getAuthentication().getName(); }

Since we use the @Secured annotation here, it requires a user to be authenticated to invoke the method. Otherwise, we'll get an AuthenticationCredentialsNotFoundException.

Hence, we need to provide a user to test our secured method. To achieve this, we decorate the test method with @WithMockUser and provide a user and roles:

@Test @WithMockUser(username = "john", roles = { "VIEWER" }) public void givenRoleViewer_whenCallGetUsername_thenReturnUsername() { String userName = userRoleService.getUsername(); assertEquals("john", userName); }

We've provided an authenticated user whose username is john and whose role is ROLE_VIEWER. If we don't specify the username or role, the default username is user and default role is ROLE_USER.

Note that it isn't necessary to add the ROLE_ prefix here, Spring Security will add that prefix automatically.

If we don't want to have that prefix, we can consider using authority instead of role.

For example, let's declare a getUsernameInLowerCase method:

@PreAuthorize("hasAuthority('SYS_ADMIN')") public String getUsernameLC(){ return getUsername().toLowerCase(); }

We could test that using authorities:

@Test @WithMockUser(username = "JOHN", authorities = { "SYS_ADMIN" }) public void givenAuthoritySysAdmin_whenCallGetUsernameLC_thenReturnUsername() { String username = userRoleService.getUsernameInLowerCase(); assertEquals("john", username); }

Conveniently, if we want to use the same user for many test cases, we can declare the @WithMockUser annotation at test class:

@RunWith(SpringRunner.class) @ContextConfiguration @WithMockUser(username = "john", roles = { "VIEWER" }) public class MockUserAtClassLevelIntegrationTest { //... }

If we wanted to run our test as an anonymous user, we could use the @WithAnonymousUser annotation:

@Test(expected = AccessDeniedException.class) @WithAnonymousUser public void givenAnomynousUser_whenCallGetUsername_thenAccessDenied() { userRoleService.getUsername(); }

In the example above, we expect an AccessDeniedException because the anonymous user isn't granted the role ROLE_VIEWER or the authority SYS_ADMIN.

5.3. Testing With a Custom UserDetailsService

For most applications, it's common to use a custom class as authentication principal. In this case, the custom class needs to implement the org.springframework.security.core.userdetails.UserDetails interface.

In this article, we declare a CustomUser class which extends the existing implementation of UserDetails, which is org.springframework.security.core.userdetails.User:

public class CustomUser extends User { private String nickName; // getter and setter }

Let's take back the example with the @PostAuthorize annotation in section 3:

@PostAuthorize("returnObject.username == authentication.principal.nickName") public CustomUser loadUserDetail(String username) { return userRoleRepository.loadUserByUserName(username); }

In this case, the method would only execute successfully if the username of the returned CustomUser is equal to the current authentication principal's nickname.

If we wanted to test that method, we could provide an implementation of UserDetailsService which could load our CustomUser based on the username:

@Test @WithUserDetails( value = "john", userDetailsServiceBeanName = "userDetailService") public void whenJohn_callLoadUserDetail_thenOK() { CustomUser user = userService.loadUserDetail("jane"); assertEquals("jane", user.getNickName()); }

Here, the @WithUserDetails annotation states that we'll use a UserDetailsService to initialize our authenticated user. The service is referred by the userDetailsServiceBeanName property. This UserDetailsService might be a real implementation or a fake for testing purposes.

Additionally, the service will use the value of the property value as the username to load UserDetails.

Conveniently, we can also decorate with a @WithUserDetails annotation at the class level, similarly to what we did with the @WithMockUser annotation.

5.4. Testing With Meta Annotations

We often find ourselves reusing the same user/roles over and over again in various tests.

For these situations, it's convenient to create a meta-annotation.

Taking back the previous example @WithMockUser(username=”john”, roles={“VIEWER”}), we can declare a meta-annotation as:

@Retention(RetentionPolicy.RUNTIME) @WithMockUser(value = "john", roles = "VIEWER") public @interface WithMockJohnViewer { }

Then we can simply use @WithMockJohnViewer in our test:

@Test @WithMockJohnViewer public void givenMockedJohnViewer_whenCallGetUsername_thenReturnUsername() { String userName = userRoleService.getUsername(); assertEquals("john", userName); }

Likewise, we can use meta-annotations to create domain-specific users using @WithUserDetails.

6. Conclusion

In this tutorial, we've explored various options for using Method Security in Spring Security.

We also have gone through a few techniques to easily test method security and learned how to reuse mocked users in different tests.

All examples of this tutorial can be found over on Github.