Spring Security @PreAuthorization pass enums in directly

Question

My question is a duplicate of Custom annotation with spring security but it went unanswered and I believe there should be a simple solution to the problem.

Basically instead of doing:

@PreAuthorize("hasPermission(T(fully.qualified.Someclass).WHATEVER, T(fully.qualified.Permission).READ")

I would like to do:

@PreAuthorize(Someclass.WHATEVER, Permission.READ)

or possibly some custom annotation that will wire up easily with spring security

This seems much cleaner to me and I would like to be able to do it if I can.

Answer 1

Indeed you can implement a custom strongly typed security annotation, though this is rather bothersome. Declare your annotation

enum Permission {
    USER_LIST,
    USER_EDIT,
    USER_ADD,
    USER_ROLE_EDIT
}

@Target(ElementType.METHOD)
@Retention(RetentionPolicy.RUNTIME)
@interface Permissions {
    Permission[] value();
}

Declare the custom implementation of org.springframework.security.access.ConfigAttribute to be used by security pipeline

class SecurityAttribute implements ConfigAttribute {
    private final List<Permission> permissions;

    public SecurityAttribute(List<Permission> permissions) {
        this.permissions = permissions;
    }

    @Override
    public String getAttribute() {
        return permissions.stream().map(p -> p.name()).collect(Collectors.joining(","));
    }
}

Declare the custom implementation of org.springframework.security.access.method.MethodSecurityMetadataSource to create the instances of SecurityAttribute from annotations

class SecurityMetadataSource extends AbstractMethodSecurityMetadataSource {
    @Override
    public Collection<ConfigAttribute> getAttributes(Method method, Class<?> targetClass) {

      //consult https://github.com/spring-projects/spring-security/blob/master/core/src/main/java/org/springframework/security/access/prepost/PrePostAnnotationSecurityMetadataSource.java
      //to implement findAnnotation  
      Permissions annotation = findAnnotation(method, targetClass, Permissions.class);
        if (annotation != null) {
            return Collections.singletonList(new SecurityAttribute(asList(annotation.value())));
        }
        return Collections.emptyList();
    }

    @Override
    public Collection<ConfigAttribute> getAllConfigAttributes() {
        return null;
    } 

}

At last declare the custom implementation org.springframework.security.access.AccessDecisionVoter

public class PermissionVoter implements AccessDecisionVoter<MethodInvocation> {
    @Override
    public boolean supports(ConfigAttribute attribute) {
        return attribute instanceof SecurityAttribute;
    }

    @Override
    public boolean supports(Class<?> clazz) {
        return MethodInvocation.class.isAssignableFrom(clazz);
    }

    @Override
    public int vote(Authentication authentication, MethodInvocation object, Collection<ConfigAttribute> attributes) {
        Optional<SecurityAttribute> securityAttribute = attributes.stream()
                .filter(attr -> attr instanceof SecurityAttribute).map(SecurityAttribute.class::cast).findFirst();
        if(!securityAttribute.isPresent()){
            return AccessDecisionVoter.ACCESS_ABSTAIN;
        }
        //authorize your principal from authentication object
        //against permissions and return ACCESS_GRANTED or ACCESS_DENIED

    }

}

and now bring them all together in your MethodSecurityConfig

@Configuration
@EnableGlobalMethodSecurity
class MethodSecurityConfig extends GlobalMethodSecurityConfiguration {

    @Override
    protected MethodSecurityMetadataSource customMethodSecurityMetadataSource() {
        return new ScpSecurityMetadataSource();
    }

    @Override
    protected AccessDecisionManager accessDecisionManager() {
        return new AffirmativeBased(Collections.singletonList(new PermissionVoter()));
    }
}