4.1.2.RELEASE
Copyright © 2004-2015
Table of Contents
- I. Preface
- 1. Getting Started
- 2. Introduction
- 3. What’s New in Spring Security 4.1
- 4. Samples and Guides (Start Here)
- 5. Java Configuration
- 6. Security Namespace Configuration
- IV. Web Application Security
- 13. The Security Filter Chain
- 14. Core Security Filters
- 15. Servlet API integration
- 16. Basic and Digest Authentication
- 17. Remember-Me Authentication
- 18. Cross Site Request Forgery (CSRF)
- 19. CORS
- 20. Security HTTP Response Headers
- 21. Session Management
- 22. Anonymous Authentication
- 23. WebSocket Security
- V. Authorization
- VI. Additional Topics
- 27. Domain Object Security (ACLs)
- 28. Pre-Authentication Scenarios
- 29. LDAP Authentication
- 29.1. Overview
- 29.2. Using LDAP with Spring Security
- 29.3. Configuring an LDAP Server
- 29.4. Implementation Classes
- 29.5. Active Directory Authentication
- 30. JSP Tag Libraries
- 31. Java Authentication and Authorization Service (JAAS) Provider
- 32. CAS Authentication
- 33. X.509 Authentication
- 34. Run-As Authentication Replacement
- 35. Spring Security Crypto Module
- 36. Concurrency Support
- 37. Spring MVC Integration
- VII. Spring Data Integration
- VIII. Appendix
- 40. Security Database Schema
- 41. The Security Namespace
- 41.1. Web Application Security
- 41.1.1. <debug>
- 41.1.2. <http>
- 41.1.3. <access-denied-handler>
- 41.1.4. <cors>
- 41.1.5. <headers>
- 41.1.6. <cache-control>
- 41.1.7. <hsts>
- 41.1.8. <hpkp>
- 41.1.9. <pins>
- 41.1.10. <pin>
- 41.1.11. <content-security-policy>
- 41.1.12. <frame-options>
- 41.1.13. <xss-protection>
- 41.1.14. <content-type-options>
- 41.1.15. <header>
- 41.1.16. <anonymous>
- 41.1.17. <csrf>
- 41.1.18. <custom-filter>
- 41.1.19. <expression-handler>
- 41.1.20. <form-login>
- 41.1.21. <http-basic>
- 41.1.22. <http-firewall> Element
- 41.1.23. <intercept-url>
- 41.1.24. <jee>
- 41.1.25. <logout>
- 41.1.26. <openid-login>
- 41.1.27. <attribute-exchange>
- 41.1.28. <openid-attribute>
- 41.1.29. <port-mappings>
- 41.1.30. <port-mapping>
- 41.1.31. <remember-me>
- 41.1.32. <request-cache> Element
- 41.1.33. <session-management>
- 41.1.34. <concurrency-control>
- 41.1.35. <x509>
- 41.1.36. <filter-chain-map>
- 41.1.37. <filter-chain>
- 41.1.38. <filter-security-metadata-source>
- 41.2. WebSocket Security
- 41.3. Authentication Services
- 41.4. Method Security
- 41.4.1. <global-method-security>
- 41.4.2. <after-invocation-provider>
- 41.4.3. <pre-post-annotation-handling>
- 41.4.4. <invocation-attribute-factory>
- 41.4.5. <post-invocation-advice>
- 41.4.6. <pre-invocation-advice>
- 41.4.7. Securing Methods using
- 41.4.8. <intercept-methods>
- 41.4.9. <method-security-metadata-source>
- 41.4.10. <protect>
- 41.5. LDAP Namespace Options
- 42. Spring Security Dependencies
- 43. Spring Security FAQ
- 43.1. General Questions
- 43.1.1. Will Spring Security take care of all my application security requirements?
- 43.1.2. Why not just use web.xml security?
- 43.1.3. What Java and Spring Framework versions are required?
- 43.1.4. I’m new to Spring Security and I need to build an application that supports CAS single sign-on over HTTPS, while allowing Basic authentication locally for certain URLs, authenticating against multiple back end user information sources (LDAP and JDBC). I’ve copied some configuration files I found but it doesn’t work. What could be wrong?
- 43.2. Common Problems
- 43.2.1. When I try to log in, I get an error message that says "Bad Credentials". What’s wrong?
- 43.2.2. My application goes into an "endless loop" when I try to login, what’s going on?
- 43.2.3. I get an exception with the message "Access is denied (user is anonymous);". What’s wrong?
- 43.2.4. Why can I still see a secured page even after I’ve logged out of my application?
- 43.2.5. I get an exception with the message "An Authentication object was not found in the SecurityContext". What’s wrong?
- 43.2.6. I can’t get LDAP authentication to work. What’s wrong with my configuration?
- 43.2.7. Session Management
- 43.2.8. I’m using Spring Security’s concurrent session control to prevent users from logging in more than once at a time. When I open another browser window after logging in, it doesn’t stop me from logging in again. Why can I log in more than once?
- 43.2.9. Why does the session Id change when I authenticate through Spring Security?
- 43.2.10. I’m using Tomcat (or some other servlet container) and have enabled HTTPS for my login page, switching back to HTTP afterwards. It doesn’t work - I just end up back at the login page after authenticating.
- 43.2.11. I’m not switching between HTTP and HTTPS but my session is still getting lost
- 43.2.12. I’m trying to use the concurrent session-control support but it won’t let me log back in, even if I’m sure I’ve logged out and haven’t exceeded the allowed sessions.
- 43.2.13. Spring Security is creating a session somewhere, even though I’ve configured it not to, by setting the create-session attribute to never.
- 43.2.14. I get a 403 Forbidden when performing a POST
- 43.2.15. I’m forwarding a request to another URL using the RequestDispatcher, but my security constraints aren’t being applied.
- 43.2.16. I have added Spring Security’s <global-method-security> element to my application context but if I add security annotations to my Spring MVC controller beans (Struts actions etc.) then they don’t seem to have an effect.
- 43.2.17. I have a user who has definitely been authenticated, but when I try to access the SecurityContextHolder during some requests, the Authentication is null. Why can’t I see the user information?
- 43.2.18. The authorize JSP Tag doesn’t respect my method security annotations when using the URL attribute.
- 43.3. Spring Security Architecture Questions
- 43.3.1. How do I know which package class X is in?
- 43.3.2. How do the namespace elements map to conventional bean configurations?
- 43.3.3. What does "ROLE_" mean and why do I need it on my role names?
- 43.3.4. How do I know which dependencies to add to my application to work with Spring Security?
- 43.3.5. What dependencies are needed to run an embedded ApacheDS LDAP server?
- 43.3.6. What is a UserDetailsService and do I need one?
- 43.4. Common "Howto" Requests
- 43.4.1. I need to login in with more information than just the username. How do I add support for extra login fields (e.g. a company name)?
- 43.4.2. How do I apply different intercept-url constraints where only the fragment value of the requested URLs differs (e.g./foo#bar and /foo#blah?
- 43.4.3. How do I access the user’s IP Address (or other web-request data) in a UserDetailsService?
- 43.4.4. How do I access the HttpSession from a UserDetailsService?
- 43.4.5. How do I access the user’s password in a UserDetailsService?
- 43.4.6. How do I define the secured URLs within an application dynamically?
- 43.4.7. How do I authenticate against LDAP but load user roles from a database?
- 43.4.8. I want to modify the property of a bean that is created by the namespace, but there is nothing in the schema to support it. What can I do short of abandoning namespace use?
- 44. Migrating from 3.x to 4.x
Spring Security is a powerful and highly customizable authentication and access-control framework. It is the de-facto standard for securing Spring-based applications.
Spring Security provides a comprehensive security solution for Java EE-based enterprise software applications. As you will discover as you venture through this reference guide, we have tried to provide you a useful and highly configurable security system.
Security is an ever-moving target, and it’s important to pursue a comprehensive, system-wide approach. In security circles we encourage you to adopt "layers of security", so that each layer tries to be as secure as possible in its own right, with successive layers providing additional security. The "tighter" the security of each layer, the more robust and safe your application will be. At the bottom level you’ll need to deal with issues such as transport security and system identification, in order to mitigate man-in-the-middle attacks. Next you’ll generally utilise firewalls, perhaps with VPNs or IP security to ensure only authorised systems can attempt to connect. In corporate environments you may deploy a DMZ to separate public-facing servers from backend database and application servers. Your operating system will also play a critical part, addressing issues such as running processes as non-privileged users and maximising file system security. An operating system will usually also be configured with its own firewall. Hopefully somewhere along the way you’ll be trying to prevent denial of service and brute force attacks against the system. An intrusion detection system will also be especially useful for monitoring and responding to attacks, with such systems able to take protective action such as blocking offending TCP/IP addresses in real-time. Moving to the higher layers, your Java Virtual Machine will hopefully be configured to minimize the permissions granted to different Java types, and then your application will add its own problem domain-specific security configuration. Spring Security makes this latter area - application security - much easier.
Of course, you will need to properly address all security layers mentioned above, together with managerial factors that encompass every layer. A non-exhaustive list of such managerial factors would include security bulletin monitoring, patching, personnel vetting, audits, change control, engineering management systems, data backup, disaster recovery, performance benchmarking, load monitoring, centralised logging, incident response procedures etc.
With Spring Security being focused on helping you with the enterprise application security layer, you will find that there are as many different requirements as there are business problem domains. A banking application has different needs from an ecommerce application. An ecommerce application has different needs from a corporate sales force automation tool. These custom requirements make application security interesting, challenging and rewarding.
Please read Chapter 1, Getting Started, in its entirety to begin with. This will introduce you to the framework and the namespace-based configuration system with which you can get up and running quite quickly. To get more of an understanding of how Spring Security works, and some of the classes you might need to use, you should then read Part II, “Architecture and Implementation”. The remaining parts of this guide are structured in a more traditional reference style, designed to be read on an as-required basis. We’d also recommend that you read up as much as possible on application security issues in general. Spring Security is not a panacea which will solve all security issues. It is important that the application is designed with security in mind from the start. Attempting to retrofit it is not a good idea. In particular, if you are building a web application, you should be aware of the many potential vulnerabilities such as cross-site scripting, request-forgery and session-hijacking which you should be taking into account from the start. The OWASP web site (http://www.owasp.org/) maintains a top ten list of web application vulnerabilities as well as a lot of useful reference information.
We hope that you find this reference guide useful, and we welcome your feedback and suggestions.
Finally, welcome to the Spring Security community.
The later parts of this guide provide an in-depth discussion of the framework architecture and implementation classes, which you need to understand if you want to do any serious customization. In this part, we’ll introduce Spring Security 4.0, give a brief overview of the project’s history and take a slightly gentler look at how to get started using the framework. In particular, we’ll look at namespace configuration which provides a much simpler way of securing your application compared to the traditional Spring bean approach where you have to wire up all the implementation classes individually.
We’ll also take a look at the sample applications that are available. It’s worth trying to run these and experimenting with them a bit even before you read the later sections - you can dip back into them as your understanding of the framework increases. Please also check out the project website as it has useful information on building the project, plus links to articles, videos and tutorials.
Spring Security provides comprehensive security services for Java EE-based enterprise software applications. There is a particular emphasis on supporting projects built using The Spring Framework, which is the leading Java EE solution for enterprise software development. If you’re not using Spring for developing enterprise applications, we warmly encourage you to take a closer look at it. Some familiarity with Spring - and in particular dependency injection principles - will help you get up to speed with Spring Security more easily.
People use Spring Security for many reasons, but most are drawn to the project after finding the security features of Java EE’s Servlet Specification or EJB Specification lack the depth required for typical enterprise application scenarios. Whilst mentioning these standards, it’s important to recognise that they are not portable at a WAR or EAR level. Therefore, if you switch server environments, it is typically a lot of work to reconfigure your application’s security in the new target environment. Using Spring Security overcomes these problems, and also brings you dozens of other useful, customisable security features.
As you probably know two major areas of application security are "authentication" and "authorization" (or "access-control"). These are the two main areas that Spring Security targets. "Authentication" is the process of establishing a principal is who they claim to be (a "principal" generally means a user, device or some other system which can perform an action in your application)."Authorization" refers to the process of deciding whether a principal is allowed to perform an action within your application. To arrive at the point where an authorization decision is needed, the identity of the principal has already been established by the authentication process. These concepts are common, and not at all specific to Spring Security.
At an authentication level, Spring Security supports a wide range of authentication models. Most of these authentication models are either provided by third parties, or are developed by relevant standards bodies such as the Internet Engineering Task Force. In addition, Spring Security provides its own set of authentication features. Specifically, Spring Security currently supports authentication integration with all of these technologies:
- HTTP BASIC authentication headers (an IETF RFC-based standard)
- HTTP Digest authentication headers (an IETF RFC-based standard)
- HTTP X.509 client certificate exchange (an IETF RFC-based standard)
- LDAP (a very common approach to cross-platform authentication needs, especially in large environments)
- Form-based authentication (for simple user interface needs)
- OpenID authentication
- Authentication based on pre-established request headers (such as Computer Associates Siteminder)
- JA-SIG Central Authentication Service (otherwise known as CAS, which is a popular open source single sign-on system)
- Transparent authentication context propagation for Remote Method Invocation (RMI) and HttpInvoker (a Spring remoting protocol)
- Automatic "remember-me" authentication (so you can tick a box to avoid re-authentication for a predetermined period of time)
- Anonymous authentication (allowing every unauthenticated call to automatically assume a particular security identity)
- Run-as authentication (which is useful if one call should proceed with a different security identity)
- Java Authentication and Authorization Service (JAAS)
- JEE container autentication (so you can still use Container Managed Authentication if desired)
- Kerberos
- Java Open Source Single Sign On (JOSSO) *
- OpenNMS Network Management Platform *
- AppFuse *
- AndroMDA *
- Mule ESB *
- Direct Web Request (DWR) *
- Grails *
- Tapestry *
- JTrac *
- Jasypt *
- Roller *
- Elastic Path *
- Atlassian Crowd *
- Your own authentication systems (see below)
(* Denotes provided by a third party
Many independent software vendors (ISVs) adopt Spring Security because of this significant choice of flexible authentication models. Doing so allows them to quickly integrate their solutions with whatever their end clients need, without undertaking a lot of engineering or requiring the client to change their environment. If none of the above authentication mechanisms suit your needs, Spring Security is an open platform and it is quite simple to write your own authentication mechanism. Many corporate users of Spring Security need to integrate with "legacy" systems that don’t follow any particular security standards, and Spring Security is happy to "play nicely" with such systems.
Irrespective of the authentication mechanism, Spring Security provides a deep set of authorization capabilities. There are three main areas of interest - authorizing web requests, authorizing whether methods can be invoked, and authorizing access to individual domain object instances. To help you understand the differences, consider the authorization capabilities found in the Servlet Specification web pattern security, EJB Container Managed Security and file system security respectively. Spring Security provides deep capabilities in all of these important areas, which we’ll explore later in this reference guide.
Spring Security began in late 2003 as "The Acegi Security System for Spring". A question was posed on the Spring Developers' mailing list asking whether there had been any consideration given to a Spring-based security implementation. At the time the Spring community was relatively small (especially compared with the size today!), and indeed Spring itself had only existed as a SourceForge project from early 2003. The response to the question was that it was a worthwhile area, although a lack of time currently prevented its exploration.
With that in mind, a simple security implementation was built and not released. A few weeks later another member of the Spring community inquired about security, and at the time this code was offered to them. Several other requests followed, and by January 2004 around twenty people were using the code. These pioneering users were joined by others who suggested a SourceForge project was in order, which was duly established in March 2004.
In those early days, the project didn’t have any of its own authentication modules. Container Managed Security was relied upon for the authentication process, with Acegi Security instead focusing on authorization. This was suitable at first, but as more and more users requested additional container support, the fundamental limitation of container-specific authentication realm interfaces became clear. There was also a related issue of adding new JARs to the container’s classpath, which was a common source of end user confusion and misconfiguration.
Acegi Security-specific authentication services were subsequently introduced. Around a year later, Acegi Security became an official Spring Framework subproject. The 1.0.0 final release was published in May 2006 - after more than two and a half years of active use in numerous production software projects and many hundreds of improvements and community contributions.
Acegi Security became an official Spring Portfolio project towards the end of 2007 and was rebranded as "Spring Security".
Today Spring Security enjoys a strong and active open source community. There are thousands of messages about Spring Security on the support forums. There is an active core of developers who work on the code itself and an active community which also regularly share patches and support their peers.
It is useful to understand how Spring Security release numbers work, as it will help you identify the effort (or lack thereof) involved in migrating to future releases of the project. Each release uses a standard triplet of integers: MAJOR.MINOR.PATCH. The intent is that MAJOR versions are incompatible, large-scale upgrades of the API. MINOR versions should largely retain source and binary compatibility with older minor versions, thought there may be some design changes and incompatible updates. PATCH level should be perfectly compatible, forwards and backwards, with the possible exception of changes which are to fix bugs and defects.
The extent to which you are affected by changes will depend on how tightly integrated your code is. If you are doing a lot of customization you are more likely to be affected than if you are using a simple namespace configuration.
You should always test your application thoroughly before rolling out a new version.
You can get hold of Spring Security in several ways. You can download a packaged distribution from the main Spring Security page, download individual jars from the Maven Central repository (or a Spring Maven repository for snapshot and milestone releases) or, alternatively, you can build the project from source yourself.
A minimal Spring Security Maven set of dependencies typically looks like the following:
pom.xml.
<dependencies> <!-- ... other dependency elements ... --> <dependency> <groupId>org.springframework.security</groupId> <artifactId>spring-security-web</artifactId> <version>4.1.2.RELEASE</version> </dependency> <dependency> <groupId>org.springframework.security</groupId> <artifactId>spring-security-config</artifactId> <version>4.1.2.RELEASE</version> </dependency> </dependencies>
If you are using additional features like LDAP, OpenID, etc. you will need to also include the appropriate Section 2.4.3, “Project Modules”.
All GA releases (i.e. versions ending in .RELEASE) are deployed to Maven Central, so no additional Maven repositories need to be declared in your pom.
If you are using a SNAPSHOT version, you will need to ensure you have the Spring Snapshot repository defined as shown below:
pom.xml.
<repositories> <!-- ... possibly other repository elements ... --> <repository> <id>spring-snapshot</id> <name>Spring Snapshot Repository</name> <url>http://repo.spring.io/snapshot</url> </repository> </repositories>
If you are using a milestone or release candidate version, you will need to ensure you have the Spring Milestone repository defined as shown below:
pom.xml.
<repositories> <!-- ... possibly other repository elements ... --> <repository> <id>spring-milestone</id> <name>Spring Milestone Repository</name> <url>http://repo.spring.io/milestone</url> </repository> </repositories>
Spring Security builds against Spring Framework 4.3.1.RELEASE, but should work with 4.0.x. The problem that many users will have is that Spring Security’s transitive dependencies resolve Spring Framework 4.3.1.RELEASE which can cause strange classpath problems.
One (tedious) way to circumvent this issue would be to include all the Spring Framework modules in a <dependencyManagement> section of your pom. An alternative approach is to include the spring-framework-bom within your <dependencyManagement> section of your pom.xml as shown below:
pom.xml.
<dependencyManagement> <dependencies> <dependency> <groupId>org.springframework</groupId> <artifactId>spring-framework-bom</artifactId> <version>4.3.1.RELEASE</version> <type>pom</type> <scope>import</scope> </dependency> </dependencies> </dependencyManagement>
This will ensure that all the transitive dependencies of Spring Security use the Spring 4.3.1.RELEASE modules.
![[Note]](./SpringSecurityReference/note.png) | Note |
|---|---|
|
This approach uses Maven’s "bill of materials" (BOM) concept and is only available in Maven 2.0.9+. For additional details about how dependencies are resolved refer to Maven’s Introduction to the Dependency Mechanism documentation. |
A minimal Spring Security Gradle set of dependencies typically looks like the following:
build.gradle.
dependencies {
compile 'org.springframework.security:spring-security-web:4.1.2.RELEASE'
compile 'org.springframework.security:spring-security-config:4.1.2.RELEASE'
}
If you are using additional features like LDAP, OpenID, etc. you will need to also include the appropriate Section 2.4.3, “Project Modules”.
All GA releases (i.e. versions ending in .RELEASE) are deployed to Maven Central, so using the mavenCentral() repository is sufficient for GA releases.
build.gradle.
repositories {
mavenCentral()
}
If you are using a SNAPSHOT version, you will need to ensure you have the Spring Snapshot repository defined as shown below:
build.gradle.
repositories {
maven { url 'https://repo.spring.io/snapshot' }
}
If you are using a milestone or release candidate version, you will need to ensure you have the Spring Milestone repository defined as shown below:
build.gradle.
repositories {
maven { url 'https://repo.spring.io/milestone' }
}
By default Gradle will use the newest version when resolving transitive versions. This means that often times no additional work is necessary when running Spring Security 4.1.2.RELEASE with Spring Framework 4.3.1.RELEASE. However, at times there can be issues that come up so it is best to mitigate this using Gradle’s ResolutionStrategy as shown below:
build.gradle.
configurations.all {
resolutionStrategy.eachDependency { DependencyResolveDetails details ->
if (details.requested.group == 'org.springframework') {
details.useVersion '4.3.1.RELEASE'
}
}
}
This will ensure that all the transitive dependencies of Spring Security use the Spring 4.3.1.RELEASE modules.
| Note |
|---|---|
|
This example uses Gradle 1.9, but may need modifications to work in future versions of Gradle since this is an incubating feature within Gradle. |
In Spring Security 3.0, the codebase has been sub-divided into separate jars which more clearly separate different functionaltiy areas and third-party dependencies. If you are using Maven to build your project, then these are the modules you will add to your pom.xml. Even if you’re not using Maven, we’d recommend that you consult the pom.xml files to get an idea of third-party dependencies and versions. Alternatively, a good idea is to examine the libraries that are included in the sample applications.
Contains core authentication and access-contol classes and interfaces, remoting support and basic provisioning APIs. Required by any application which uses Spring Security. Supports standalone applications, remote clients, method (service layer) security and JDBC user provisioning. Contains the top-level packages:
-
org.springframework.security.core -
org.springframework.security.access -
org.springframework.security.authentication -
org.springframework.security.provisioning
Provides intergration with Spring Remoting. You don’t need this unless you are writing a remote client which uses Spring Remoting. The main package is org.springframework.security.remoting.
Contains filters and related web-security infrastructure code. Anything with a servlet API dependency. You’ll need it if you require Spring Security web authentication services and URL-based access-control. The main package is org.springframework.security.web.
Contains the security namespace parsing code & Java configuration code.
You need it if you are using the Spring Security XML namespace for configuration or Spring Security’s Java Configuration support.
The main package is org.springframework.security.config.
None of the classes are intended for direct use in an application.
LDAP authentication and provisioning code. Required if you need to use LDAP authentication or manage LDAP user entries. The top-level package is org.springframework.security.ldap.
Specialized domain object ACL implementation. Used to apply security to specific domain object instances within your application. The top-level package is org.springframework.security.acls.
Spring Security’s CAS client integration. If you want to use Spring Security web authentication with a CAS single sign-on server. The top-level package is org.springframework.security.cas.
OpenID web authentication support. Used to authenticate users against an external OpenID server. org.springframework.security.openid. Requires OpenID4Java.
Since Spring Security is an Open Source project, we’d strongly encourage you to check out the source code using git. This will give you full access to all the sample applications and you can build the most up to date version of the project easily. Having the source for a project is also a huge help in debugging. Exception stack traces are no longer obscure black-box issues but you can get straight to the line that’s causing the problem and work out what’s happening. The source is the ultimate documentation for a project and often the simplest place to find out how something actually works.
To obtain the source for the project, use the following git command:
git clone https://github.com/spring-projects/spring-security.git
This will give you access to the entire project history (including all releases and branches) on your local machine.
There were 100+ RC1 issues and 60+ RC2 issues fixed in Spring Security 4.1.
Here is the list of improvements:
- Simplified UserDetailsService Java Configuration
- Simplified AuthenticationProvider Java Configuration
-
Configurable Content Negotiating
LogoutSuccessHandler(s) viaLogoutConfigurer -
Configurable
InvalidSessionStrategyviaSessionManagementConfigurer -
Ability to add a
Filterat a specific location in the chain usingHttpSecurity.addFilterAt
- MvcRequestMatcher
- Content Security Policy (CSP)
- HTTP Public Key Pinning (HPKP)
- CORS
- CookieCsrfTokenRepository provides simple AngularJS & CSRF integration
-
Added
ForwardAuthenticationFailureHandler&ForwardAuthenticationSuccessHandler -
AuthenticationPrincipal supports expression attribute to support transforming the
Authentication.getPrincipal()object (i.e. handling immutable customUserdomain objects)
-
SCrypt support with
SCryptPasswordEncoder - PBKDF2 support with Pbkdf2PasswordEncoder
-
New
BytesEncryptorimplementation for BouncyCastle using AES/CBC/PKCS5Padding and AES/GCM/NoPadding algorithms
- @WithAnonymousUser
-
@WithUserDetails allows specifying the
UserDetailsServicebean name - Test Meta Annotations
-
Ability to mock a list of
GrantedAuthorityusingSecurityMockMvcResultMatchers.withAuthorities
If you are looking to get started with Spring Security, the best place to start is our Sample Applications.
Table 4.1. Sample Applications
| Source | Description | Guide |
|---|---|---|
Demonstrates how to integrate Spring Security with an existing application using Java-based configuration. | ||
Demonstrates how to integrate Spring Security with an existing Spring Boot application. | ||
Demonstrates how to integrate Spring Security with an existing application using XML-based configuration. | ||
Demonstrates how to integrate Spring Security with an existing Spring MVC application. | ||
Demonstrates how to create a custom login form. |
General support for Java Configuration was added to Spring framework in Spring 3.1. Since Spring Security 3.2 there has been Spring Security Java Configuration support which enables users to easily configure Spring Security without the use of any XML.
If you are familiar with the Chapter 6, Security Namespace Configuration then you should find quite a few similarities between it and the Security Java Configuration support.
| Note |
|---|---|
|
Spring Security provides lots of sample applications that end in |
The first step is to create our Spring Security Java Configuration. The configuration creates a Servlet Filter known as the springSecurityFilterChain which is responsible for all the security (protecting the application URLs, validating submitted username and passwords, redirecting to the log in form, etc) within your application. You can find the most basic example of a Spring Security Java Configuration below:
import org.springframework.beans.factory.annotation.Autowired; import org.springframework.context.annotation.*; import org.springframework.security.config.annotation.authentication.builders.*; import org.springframework.security.config.annotation.web.configuration.*; @EnableWebSecurity public class WebSecurityConfig extends WebSecurityConfigurerAdapter { @Autowired public void configureGlobal(AuthenticationManagerBuilder auth) throws Exception { auth .inMemoryAuthentication() .withUser("user").password("password").roles("USER"); } }
| Note |
|---|---|
|
The name of the configureGlobal method is not important. However, it is important to only configure AuthenticationManagerBuilder in a class annotated with either |
There really isn’t much to this configuration, but it does a lot. You can find a summary of the features below:
- Require authentication to every URL in your application
- Generate a login form for you
- Allow the user with the Username user and the Password password to authenticate with form based authentication
- Allow the user to logout
- CSRF attack prevention
- Session Fixation protection
-
Security Header integration
- HTTP Strict Transport Security for secure requests
- X-Content-Type-Options integration
- Cache Control (can be overridden later by your application to allow caching of your static resources)
- X-XSS-Protection integration
- X-Frame-Options integration to help prevent Clickjacking
-
Integrate with the following Servlet API methods
The next step is to register the springSecurityFilterChain with the war. This can be done in Java Configuration with Spring’s WebApplicationInitializer support in a Servlet 3.0+ environment. Not suprisingly, Spring Security provides a base class AbstractSecurityWebApplicationInitializer that will ensure the springSecurityFilterChain gets registered for you. The way in which we use AbstractSecurityWebApplicationInitializer differs depending on if we are already using Spring or if Spring Security is the only Spring component in our application.
- Section 5.1.2, “AbstractSecurityWebApplicationInitializer without Existing Spring” - Use these instructions if you are not using Spring already
- Section 5.1.3, “AbstractSecurityWebApplicationInitializer with Spring MVC” - Use these instructions if you are already using Spring
If you are not using Spring or Spring MVC, you will need to pass in the WebSecurityConfig into the superclass to ensure the configuration is picked up. You can find an example below:
import org.springframework.security.web.context.*; public class SecurityWebApplicationInitializer extends AbstractSecurityWebApplicationInitializer { public SecurityWebApplicationInitializer() { super(WebSecurityConfig.class); } }
The SecurityWebApplicationInitializer will do the following things:
- Automatically register the springSecurityFilterChain Filter for every URL in your application
- Add a ContextLoaderListener that loads the WebSecurityConfig.
If we were using Spring elsewhere in our application we probably already had a WebApplicationInitializer that is loading our Spring Configuration. If we use the previous configuration we would get an error. Instead, we should register Spring Security with the existing ApplicationContext. For example, if we were using Spring MVC our SecurityWebApplicationInitializer would look something like the following:
import org.springframework.security.web.context.*; public class SecurityWebApplicationInitializer extends AbstractSecurityWebApplicationInitializer { }
This would simply only register the springSecurityFilterChain Filter for every URL in your application. After that we would ensure that WebSecurityConfig was loaded in our existing ApplicationInitializer. For example, if we were using Spring MVC it would be added in the getRootConfigClasses()
public class MvcWebApplicationInitializer extends AbstractAnnotationConfigDispatcherServletInitializer { @Override protected Class<?>[] getRootConfigClasses() { return new Class[] { WebSecurityConfig.class }; } // ... other overrides ... }
Thus far our WebSecurityConfig only contains information about how to authenticate our users. How does Spring Security know that we want to require all users to be authenticated? How does Spring Security know we want to support form based authentication? The reason for this is that the WebSecurityConfigurerAdapter provides a default configuration in the configure(HttpSecurity http) method that looks like:
protected void configure(HttpSecurity http) throws Exception { http .authorizeRequests() .anyRequest().authenticated() .and() .formLogin() .and() .httpBasic(); }
The default configuration above:
- Ensures that any request to our application requires the user to be authenticated
- Allows users to authenticate with form based login
- Allows users to authenticate with HTTP Basic authentication
You will notice that this configuration is quite similar the XML Namespace configuration:
<http> <intercept-url pattern="/**" access="authenticated"/> <form-login /> <http-basic /> </http>
The Java Configuration equivalent of closing an XML tag is expressed using the and() method which allows us to continue configuring the parent. If you read the code it also makes sense. I want to configure authorized requests and configure form login and configure HTTP Basic authentication.
However, Java Configuration has different defaults URLs and parameters. Keep this in mind when creating custom login pages. The result is that our URLs are more RESTful. Additionally, it is not quite so obvious we are using Spring Security which helps to prevent information leaks. For example:
You might be wondering where the login form came from when you were prompted to log in, since we made no mention of any HTML files or JSPs. Since Spring Security’s default configuration does not explicitly set a URL for the login page, Spring Security generates one automatically, based on the features that are enabled and using standard values for the URL which processes the submitted login, the default target URL the user will be sent to after logging in and so on.
While the automatically generated log in page is convenient to get up and running quickly, most applications will want to provide their own log in page. To do so we can update our configuration as seen below:
protected void configure(HttpSecurity http) throws Exception { http .authorizeRequests() .anyRequest().authenticated() .and() .formLogin() .loginPage("/login").permitAll();
}
|
The updated configuration specifies the location of the log in page. |
|
We must grant all users (i.e. unauthenticated users) access to our log in page. The |
An example log in page implemented with JSPs for our current configuration can be seen below:
| Note |
|---|---|
|
The login page below represents our current configuration. We could easily update our configuration if some of the defaults do not meet our needs. |
<c:url value="/login" var="loginUrl"/> <form action="${loginUrl}" method="post"><p> You have been logged out. </p> </c:if> <p> <label for="username">Username</label> <input type="text" id="username" name="username"/>
</p> <p> <label for="password">Password</label> <input type="password" id="password" name="password"/>
</p> <input type="hidden"
name="${_csrf.parameterName}" value="${_csrf.token}"/> <button type="submit" class="btn">Log in</button> </form>
|
A POST to the |
|
If the query parameter |
|
If the query parameter |
|
The username must be present as the HTTP parameter named username |
|
The password must be present as the HTTP parameter named password |
|
We must Section 18.4.3, “Include the CSRF Token” To learn more read the Chapter 18, Cross Site Request Forgery (CSRF) section of the reference |
Our examples have only required users to be authenticated and have done so for every URL in our application. We can specify custom requirements for our URLs by adding multiple children to our http.authorizeRequests() method. For example:
protected void configure(HttpSecurity http) throws Exception { http .authorizeRequests()
|
There are multiple children to the |
|
We specified multiple URL patterns that any user can access. Specifically, any user can access a request if the URL starts with "/resources/", equals "/signup", or equals "/about". |
|
Any URL that starts with "/admin/" will be resticted to users who have the role "ROLE_ADMIN". You will notice that since we are invoking the |
|
Any URL that starts with "/db/" requires the user to have both "ROLE_ADMIN" and "ROLE_DBA". You will notice that since we are using the |
|
Any URL that has not already been matched on only requires that the user be authenticated |
When using the
WebSecurityConfigurerAdapter,
logout capabilities are automatically applied. The default is that accessing the
URL /logout will log the user out by:
- Invalidating the HTTP Session
- Cleaning up any RememberMe authentication that was configured
-
Clearing the
SecurityContextHolder -
Redirect to
/login?logout
Similar to configuring login capabilities, however, you also have various options to further customize your logout requirements:
protected void configure(HttpSecurity http) throws Exception { http .logout().and() ... }
|
Provides logout support. This is automatically applied when using |
|
The URL that triggers log out to occur (default is |
|
The URL to redirect to after logout has occurred. The default is |
|
Let’s you specify a custom |
|
Specify whether to invalidate the |
|
Adds a |
|
Allows specifying the names of cookies to be removed on logout success. This is a shortcut for adding a |
| Note |
|---|---|
|
Logouts can of course also be configured using the XML Namespace notation. Please see the documentation for the logout element in the Spring Security XML Namespace section for further details. |
Generally, in order to customize logout functionality, you can add
LogoutHandler
and/or
LogoutSuccessHandler
implementations. For many common scenarios, these handlers are applied under the
covers when using the fluent API.
Generally, LogoutHandler
implementations indicate classes that are able to participate in logout handling.
They are expected to be invoked to perform necessary cleanup. As such they should
not throw exceptions. Various implementations are provided:
Please see Section 17.4, “Remember-Me Interfaces and Implementations” for details.
Instead of providing LogoutHandler implementations directly, the fluent API
also provides shortcuts that provide the respective LogoutHandler implementations
under the covers. E.g. deleteCookies() allows specifying the names of one or
more cookies to be removed on logout success. This is a shortcut compared to adding a
CookieClearingLogoutHandler.
The LogoutSuccessHandler is called after a successful logout by the LogoutFilter,
to handle e.g. redirection or forwarding to the appropriate destination. Note that the
interface is almost the same as the LogoutHandler but may raise an exception.
The following implementations are provided:
- SimpleUrlLogoutSuccessHandler
- HttpStatusReturningLogoutSuccessHandler
As mentioned above, you don’t need to specify the SimpleUrlLogoutSuccessHandler directly.
Instead, the fluent API provides a shortcut by setting the logoutSuccessUrl().
This will setup the SimpleUrlLogoutSuccessHandler under the covers. The provided URL will
be redirected to after a logout has occurred. The default is /login?logout.
The HttpStatusReturningLogoutSuccessHandler can be interesting in REST API type
scenarios. Instead of redirecting to a URL upon the successful logout, this LogoutSuccessHandler
allows you to provide a plain HTTP status code to be returned. If not configured
a status code 200 will be returned by default.
- Logout Handling
- Testing Logout
- HttpServletRequest.logout()
- Section 17.4, “Remember-Me Interfaces and Implementations”
- Logging Out in section CSRF Caveats
- Section Single Logout (CAS protocol)
- Documentation for the logout element in the Spring Security XML Namespace section
Thus far we have only taken a look at the most basic authentication configuration. Let’s take a look at a few slightly more advanced options for configuring authentication.
We have already seen an example of configuring in memory authentication for a single user. Below is an example to configure multiple users:
@Autowired public void configureGlobal(AuthenticationManagerBuilder auth) throws Exception { auth .inMemoryAuthentication() .withUser("user").password("password").roles("USER").and() .withUser("admin").password("password").roles("USER", "ADMIN"); }
You can find the updates to suppport JDBC based authentication. The example below assumes that you have already defined a DataSource within your application. The jdbc-javaconfig sample provides a complete example of using JDBC based authentication.
@Autowired private DataSource dataSource; @Autowired public void configureGlobal(AuthenticationManagerBuilder auth) throws Exception { auth .jdbcAuthentication() .dataSource(dataSource) .withDefaultSchema() .withUser("user").password("password").roles("USER").and() .withUser("admin").password("password").roles("USER", "ADMIN"); }
You can find the updates to suppport LDAP based authentication. The ldap-javaconfig sample provides a complete example of using LDAP based authentication.
@Autowired private DataSource dataSource; @Autowired public void configureGlobal(AuthenticationManagerBuilder auth) throws Exception { auth .ldapAuthentication() .userDnPatterns("uid={0},ou=people") .groupSearchBase("ou=groups"); }
The example above uses the following LDIF and an embedded Apache DS LDAP instance.
users.ldif.
dn: ou=groups,dc=springframework,dc=org objectclass: top objectclass: organizationalUnit ou: groups dn: ou=people,dc=springframework,dc=org objectclass: top objectclass: organizationalUnit ou: people dn: uid=admin,ou=people,dc=springframework,dc=org objectclass: top objectclass: person objectclass: organizationalPerson objectclass: inetOrgPerson cn: Rod Johnson sn: Johnson uid: admin userPassword: password dn: uid=user,ou=people,dc=springframework,dc=org objectclass: top objectclass: person objectclass: organizationalPerson objectclass: inetOrgPerson cn: Dianne Emu sn: Emu uid: user userPassword: password dn: cn=user,ou=groups,dc=springframework,dc=org objectclass: top objectclass: groupOfNames cn: user uniqueMember: uid=admin,ou=people,dc=springframework,dc=org uniqueMember: uid=user,ou=people,dc=springframework,dc=org dn: cn=admin,ou=groups,dc=springframework,dc=org objectclass: top objectclass: groupOfNames cn: admin uniqueMember: uid=admin,ou=people,dc=springframework,dc=org
You can define custom authentication by exposing a custom AuthenticationProvider as a bean.
For example, the following will customize authentication assuming that SpringAuthenticationProvider implements AuthenticationProvider:
| Note |
|---|---|
|
This is only used if the |
@Bean public SpringAuthenticationProvider springAuthenticationProvider() { return new SpringAuthenticationProvider(); }
You can define custom authentication by exposing a custom UserDetailsService as a bean.
For example, the following will customize authentication assuming that SpringDataUserDetailsService implements UserDetailsService:
| Note |
|---|---|
|
This is only used if the |
@Bean public SpringDataUserDetailsService springDataUserDetailsService() { return new SpringDataUserDetailsService(); }
You can also customize how passwords are encoded by exposing a PasswordEncoder as a bean.
For example, if you use bcrypt you can add a bean definition as shown below:
@Bean public BCryptPasswordEncoder passwordEncoder() { return new BCryptPasswordEncoder(); }
We can configure multiple HttpSecurity instances just as we can have multiple <http> blocks. The key is to extend the WebSecurityConfigurationAdapter multiple times. For example, the following is an example of having a different configuration for URL’s that start with /api/.
@EnableWebSecurity public class MultiHttpSecurityConfig { @Autowired public void configureGlobal(AuthenticationManagerBuilder auth) {
|
Configure Authentication as normal |
|
Create an instance of |
|
The |
|
Create another instance of |
From version 2.0 onwards Spring Security has improved support substantially for adding security to your service layer methods. It provides support for JSR-250 annotation security as well as the framework’s original @Secured annotation. From 3.0 you can also make use of new expression-based annotations. You can apply security to a single bean, using the intercept-methods element to decorate the bean declaration, or you can secure multiple beans across the entire service layer using the AspectJ style pointcuts.
We can enable annotation-based security using the @EnableGlobalMethodSecurity annotation on any @Configuration instance. For example, the following would enable Spring Security’s @Secured annotation.
@EnableGlobalMethodSecurity(securedEnabled = true) public class MethodSecurityConfig { // ... }
Adding an annotation to a method (on an class or interface) would then limit the access to that method accordingly. Spring Security’s native annotation support defines a set of attributes for the method. These will be passed to the AccessDecisionManager for it to make the actual decision:
public interface BankService { @Secured("IS_AUTHENTICATED_ANONYMOUSLY") public Account readAccount(Long id); @Secured("IS_AUTHENTICATED_ANONYMOUSLY") public Account[] findAccounts(); @Secured("ROLE_TELLER") public Account post(Account account, double amount); }
Support for JSR-250 annotations can be enabled using
@EnableGlobalMethodSecurity(jsr250Enabled = true) public class MethodSecurityConfig { // ... }
These are standards-based and allow simple role-based constraints to be applied but do not have the power Spring Security’s native annotations. To use the new expression-based syntax, you would use
@EnableGlobalMethodSecurity(prePostEnabled = true) public class MethodSecurityConfig { // ... }
and the equivalent Java code would be
public interface BankService { @PreAuthorize("isAnonymous()") public Account readAccount(Long id); @PreAuthorize("isAnonymous()") public Account[] findAccounts(); @PreAuthorize("hasAuthority('ROLE_TELLER')") public Account post(Account account, double amount); }
Sometimes you may need to perform operations that are more complicated than are possible with the @EnableGlobalMethodSecurity annotation allow. For these instances, you can extend the GlobalMethodSecurityConfiguration ensuring that the @EnableGlobalMethodSecurity annotation is present on your subclass. For example, if you wanted to provide a custom MethodSecurityExpressionHandler, you could use the following configuration:
@EnableGlobalMethodSecurity(prePostEnabled = true) public class MethodSecurityConfig extends GlobalMethodSecurityConfiguration { @Override protected MethodSecurityExpressionHandler createExpressionHandler() { // ... create and return custom MethodSecurityExpressionHandler ... return expressionHandler; } }
For additional information about methods that can be overriden, refer to the GlobalMethodSecurityConfiguration Javadoc.
Spring Security’s Java Configuration does not expose every property of every object that it configures. This simplifies the configuration for a majority of users. Afterall, if every property was exposed, users could use standard bean configuration.
While there are good reasons to not directly expose every property, users may still need more advanced configuration options. To address this Spring Security introduces the concept of an ObjectPostProcessor which can used to modify or replace many of the Object instances created by the Java Configuration. For example, if you wanted to configure the filterSecurityPublishAuthorizationSuccess property on FilterSecurityInterceptor you could use the following:
@Override protected void configure(HttpSecurity http) throws Exception { http .authorizeRequests() .anyRequest().authenticated() .withObjectPostProcessor(new ObjectPostProcessor<FilterSecurityInterceptor>() { public <O extends FilterSecurityInterceptor> O postProcess( O fsi) { fsi.setPublishAuthorizationSuccess(true); return fsi; } }); }
Namespace configuration has been available since version 2.0 of the Spring framework. It allows you to supplement the traditional Spring beans application context syntax with elements from additional XML schema. You can find more information in the Spring Reference Documentation. A namespace element can be used simply to allow a more concise way of configuring an individual bean or, more powerfully, to define an alternative configuration syntax which more closely matches the problem domain and hides the underlying complexity from the user. A simple element may conceal the fact that multiple beans and processing steps are being added to the application context. For example, adding the following element from the security namespace to an application context will start up an embedded LDAP server for testing use within the application:
<security:ldap-server />
This is much simpler than wiring up the equivalent Apache Directory Server beans. The most common alternative configuration requirements are supported by attributes on the ldap-server element and the user is isolated
from worrying about which beans they need to create and what the bean property names are. [1]. Use of a good XML
editor while editing the application context file should provide information on the attributes and elements that are available. We would recommend that you try out the
Spring Tool Suite as it has special features for working with standard Spring namespaces.
To start using the security namespace in your application context, you need to have the spring-security-config jar on your classpath. Then all you need to do is add the schema declaration to your application context file:
<beans xmlns="http://www.springframework.org/schema/beans" xmlns:security="http://www.springframework.org/schema/security" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-3.0.xsd http://www.springframework.org/schema/security http://www.springframework.org/schema/security/spring-security.xsd"> ... </beans>
In many of the examples you will see (and in the sample applications), we will often use "security" as the default namespace rather than "beans", which means we can omit the prefix on all the security namespace elements, making the content easier to read. You may also want to do this if you have your application context divided up into separate files and have most of your security configuration in one of them. Your security application context file would then start like this
<beans:beans xmlns="http://www.springframework.org/schema/security" xmlns:beans="http://www.springframework.org/schema/beans" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-3.0.xsd http://www.springframework.org/schema/security http://www.springframework.org/schema/security/spring-security.xsd"> ... </beans:beans>
We’ll assume this syntax is being used from now on in this chapter.
The namespace is designed to capture the most common uses of the framework and provide a simplified and concise syntax for enabling them within an application. The design is based around the large-scale dependencies within the framework, and can be divided up into the following areas:
- Web/HTTP Security - the most complex part. Sets up the filters and related service beans used to apply the framework authentication mechanisms, to secure URLs, render login and error pages and much more.
- Business Object (Method) Security - options for securing the service layer.
- AuthenticationManager - handles authentication requests from other parts of the framework.
- AccessDecisionManager - provides access decisions for web and method security. A default one will be registered, but you can also choose to use a custom one, declared using normal Spring bean syntax.
- AuthenticationProviders - mechanisms against which the authentication manager authenticates users. The namespace provides supports for several standard options and also a means of adding custom beans declared using a traditional syntax.
- UserDetailsService - closely related to authentication providers, but often also required by other beans.
We’ll see how to configure these in the following sections.
In this section, we’ll look at how you can build up a namespace configuration to use some of the main features of the framework. Let’s assume you initially want to get up and running as quickly as possible and add authentication support and access control to an existing web application, with a few test logins. Then we’ll look at how to change over to authenticating against a database or other security repository. In later sections we’ll introduce more advanced namespace configuration options.
The first thing you need to do is add the following filter declaration to your web.xml file:
<filter> <filter-name>springSecurityFilterChain</filter-name> <filter-class>org.springframework.web.filter.DelegatingFilterProxy</filter-class> </filter> <filter-mapping> <filter-name>springSecurityFilterChain</filter-name> <url-pattern>/*</url-pattern> </filter-mapping>
This provides a hook into the Spring Security web infrastructure. DelegatingFilterProxy is a Spring Framework class which delegates to a filter implementation which is defined as a Spring bean in your application
context. In this case, the bean is named "springSecurityFilterChain", which is an internal infrastructure bean created by the namespace to handle web security. Note that you should not use this bean name yourself. Once
you’ve added this to your web.xml, you’re ready to start editing your application context file. Web security services are configured using the <http> element.
All you need to enable web security to begin with is
<http> <intercept-url pattern="/**" access="hasRole('USER')" /> <form-login /> <logout /> </http>
Which says that we want all URLs within our application to be secured, requiring the role ROLE_USER to access them, we want to log in to the application using a form with username and password, and that we want a
logout URL registered which will allow us to log out of the application. <http> element is the parent for all web-related namespace functionality. The <intercept-url> element defines a pattern which is matched
against the URLs of incoming requests using an ant path style syntax [2]. You can also use regular-expression matching as an alternative (see the namespace appendix for more details). The access attribute defines the access requirements for requests matching
the given pattern. With the default configuration, this is typically a comma-separated list of roles, one of which a user must have to be allowed to make the request. The prefix"ROLE_" is a marker which indicates that a
simple comparison with the user’s authorities should be made. In other words, a normal role-based check should be used. Access-control in Spring Security is not limited to the use of simple roles (hence the use of the
prefix to differentiate between different types of security attributes). We’ll see later how the interpretation can vary footnote:[The interpretation of the comma-separated values in the access attribute depends on the
implementation of the –1— which is used. In Spring Security 3.0, the attribute can also be populated with an –2—.
| Note |
|---|---|
|
You can use multiple |
To add some users, you can define a set of test data directly in the namespace:
<authentication-manager> <authentication-provider> <user-service> <user name="jimi" password="jimispassword" authorities="ROLE_USER, ROLE_ADMIN" /> <user name="bob" password="bobspassword" authorities="ROLE_USER" /> </user-service> </authentication-provider> </authentication-manager>
The configuration above defines two users, their passwords and their roles within the application (which will be used for access control). It is also possible to load user information from a standard properties file using the properties attribute on user-service. See the section on in-memory authentication for more details on the file format. Using the <authentication-provider> element means that the user information will be used by the authentication manager to process authentication requests. You can have multiple <authentication-provider> elements to define different authentication sources and each will be consulted in turn.
At this point you should be able to start up your application and you will be required to log in to proceed. Try it out, or try experimenting with the"tutorial" sample application that comes with the project.
You might be wondering where the login form came from when you were prompted to log in, since we made no mention of any HTML files or JSPs. In fact, since we didn’t explicitly set a URL for the login page, Spring Security generates one automatically, based on the features that are enabled and using standard values for the URL which processes the submitted login, the default target URL the user will be sent to after logging in and so on. However, the namespace offers plenty of support to allow you to customize these options. For example, if you want to supply your own login page, you could use:
<http> <intercept-url pattern="/login.jsp*" access="IS_AUTHENTICATED_ANONYMOUSLY"/> <intercept-url pattern="/**" access="ROLE_USER" /> <form-login login-page='/login.jsp'/> </http>
Also note that we’ve added an extra intercept-url element to say that any requests for the login page should be available to anonymous users [3] and also
the AuthenticatedVoter class for more details on how the value IS_AUTHENTICATED_ANONYMOUSLY is processed.]. Otherwise the request would be matched by the pattern /** and it wouldn’t be
possible to access the login page itself! This is a common configuration error and will result in an infinite loop in the application. Spring Security will emit a warning in the log if your login page appears to be
secured. It is also possible to have all requests matching a particular pattern bypass the security filter chain completely, by defining a separate http element for the pattern like this:
<http pattern="/css/**" security="none"/> <http pattern="/login.jsp*" security="none"/> <http use-expressions="false"> <intercept-url pattern="/**" access="ROLE_USER" /> <form-login login-page='/login.jsp'/> </http>
From Spring Security 3.1 it is now possible to use multiple http elements to define separate security filter chain configurations for different request patterns. If the pattern attribute is omitted from an http element, it matches all requests. Creating an unsecured pattern is a simple example of this syntax, where the pattern is mapped to an empty filter chain [4]. We’ll look at this new syntax in more detail in the chapter on the Security Filter Chain.
It’s important to realise that these unsecured requests will be completely oblivious to any Spring Security web-related configuration or additional attributes such as requires-channel, so you will not be able to access information on the current user or call secured methods during the request. Use access='IS_AUTHENTICATED_ANONYMOUSLY' as an alternative if you still want the security filter chain to be applied.
If you want to use basic authentication instead of form login, then change the configuration to
<http use-expressions="false"> <intercept-url pattern="/**" access="ROLE_USER" /> <http-basic /> </http>
Basic authentication will then take precedence and will be used to prompt for a login when a user attempts to access a protected resource. Form login is still available in this configuration if you wish to use it, for example through a login form embedded in another web page.
If a form login isn’t prompted by an attempt to access a protected resource, the default-target-url option comes into play. This is the URL the user will be taken to after successfully logging in, and defaults to "/". You can also configure things so that the user always ends up at this page (regardless of whether the login was "on-demand" or they explicitly chose to log in) by setting the always-use-default-target attribute to "true". This is useful if your application always requires that the user starts at a "home" page, for example:
<http pattern="/login.htm*" security="none"/> <http use-expressions="false"> <intercept-url pattern='/**' access='ROLE_USER' /> <form-login login-page='/login.htm' default-target-url='/home.htm' always-use-default-target='true' /> </http>
For even more control over the destination, you can use the authentication-success-handler-ref attribute as an alternative to default-target-url. The referenced bean should be an instance of AuthenticationSuccessHandler. You’ll find more on this in the Core Filters chapter and also in the namespace appendix, as well as information on how to customize the flow when authentication fails.
The logout element adds support for logging out by navigating to a particular URL. The default logout URL is /logout, but you can set it to something else using the logout-url attribute. More information on other available attributes may be found in the namespace appendix.
In practice you will need a more scalable source of user information than a few names added to the application context file. Most likely you will want to store your user information in something like a database or an LDAP server. LDAP namespace configuration is dealt with in the LDAP chapter, so we won’t cover it here. If you have a custom implementation of Spring Security’s UserDetailsService, called "myUserDetailsService" in your application context, then you can authenticate against this using
<authentication-manager> <authentication-provider user-service-ref='myUserDetailsService'/> </authentication-manager>
If you want to use a database, then you can use
<authentication-manager> <authentication-provider> <jdbc-user-service data-source-ref="securityDataSource"/> </authentication-provider> </authentication-manager>
Where "securityDataSource" is the name of a DataSource bean in the application context, pointing at a database containing the standard Spring Security user data tables. Alternatively, you could configure a Spring Security JdbcDaoImpl bean and point at that using the user-service-ref attribute:
<authentication-manager> <authentication-provider user-service-ref='myUserDetailsService'/> </authentication-manager> <beans:bean id="myUserDetailsService" class="org.springframework.security.core.userdetails.jdbc.JdbcDaoImpl"> <beans:property name="dataSource" ref="dataSource"/> </beans:bean>
You can also use standard AuthenticationProvider beans as follows
<authentication-manager> <authentication-provider ref='myAuthenticationProvider'/> </authentication-manager>
where myAuthenticationProvider is the name of a bean in your application context which implements AuthenticationProvider. You can use multiple authentication-provider elements, in which case the providers will be queried in the order they are declared. See Section 6.6, “The Authentication Manager and the Namespace” for more on information on how the Spring Security AuthenticationManager is configured using the namespace.
Passwords should always be encoded using a secure hashing algorithm designed for the purpose (not a standard algorithm like SHA or MD5). This is supported by the <password-encoder> element. With bcrypt encoded passwords, the original authentication provider configuration would look like this:
<beans:bean name="bcryptEncoder" class="org.springframework.security.crypto.bcrypt.BCryptPasswordEncoder"/> <authentication-manager> <authentication-provider> <password-encoder ref="bcryptEncoder"/> <user-service> <user name="jimi" password="d7e6351eaa13189a5a3641bab846c8e8c69ba39f" authorities="ROLE_USER, ROLE_ADMIN" /> <user name="bob" password="4e7421b1b8765d8f9406d87e7cc6aa784c4ab97f" authorities="ROLE_USER" /> </user-service> </authentication-provider> </authentication-manager>
Bcrypt is a good choice for most cases, unless you have a legacy system which forces you to use a different algorithm. If you are using a simple hashing algorithm or, even worse, storing plain text passwords, then you should consider migrating to a more secure option like bcrypt.
See the separate Remember-Me chapter for information on remember-me namespace configuration.
If your application supports both HTTP and HTTPS, and you require that particular URLs can only be accessed over HTTPS, then this is directly supported using the requires-channel attribute on <intercept-url>:
<http> <intercept-url pattern="/secure/**" access="ROLE_USER" requires-channel="https"/> <intercept-url pattern="/**" access="ROLE_USER" requires-channel="any"/> ... </http>
With this configuration in place, if a user attempts to access anything matching the "/secure/**" pattern using HTTP, they will first be redirected to an HTTPS URL [5]. The available options are "http", "https" or "any". Using the value "any" means that either HTTP or HTTPS can be used.
If your application uses non-standard ports for HTTP and/or HTTPS, you can specify a list of port mappings as follows:
<http> ... <port-mappings> <port-mapping http="9080" https="9443"/> </port-mappings> </http>
Note that in order to be truly secure, an application should not use HTTP at all or switch between HTTP and HTTPS. It should start in HTTPS (with the user entering an HTTPS URL) and use a secure connection throughout to avoid any possibility of man-in-the-middle attacks.
You can configure Spring Security to detect the submission of an invalid session ID and redirect the user to an appropriate URL. This is achieved through the session-management element:
<http> ... <session-management invalid-session-url="/invalidSession.htm" /> </http>
Note that if you use this mechanism to detect session timeouts, it may falsely report an error if the user logs out and then logs back in without closing the browser. This is because the session cookie is not cleared when you invalidate the session and will be resubmitted even if the user has logged out. You may be able to explicitly delete the JSESSIONID cookie on logging out, for example by using the following syntax in the logout handler:
<http> <logout delete-cookies="JSESSIONID" /> </http>
Unfortunately this can’t be guaranteed to work with every servlet container, so you will need to test it in your environment
| Note |
|---|---|
|
If you are running your application behind a proxy, you may also be able to remove the session cookie by configuring the proxy server. For example, using Apache HTTPD’s mod_headers, the following directive would delete the <LocationMatch "/tutorial/logout"> Header always set Set-Cookie "JSESSIONID=;Path=/tutorial;Expires=Thu, 01 Jan 1970 00:00:00 GMT" </LocationMatch> |
If you wish to place constraints on a single user’s ability to log in to your application, Spring Security supports this out of the box with the following simple additions. First you need to add the following listener to your web.xml file to keep Spring Security updated about session lifecycle events:
<listener> <listener-class> org.springframework.security.web.session.HttpSessionEventPublisher </listener-class> </listener>
Then add the following lines to your application context:
<http> ... <session-management> <concurrency-control max-sessions="1" /> </session-management> </http>
This will prevent a user from logging in multiple times - a second login will cause the first to be invalidated. Often you would prefer to prevent a second login, in which case you can use
<http> ... <session-management> <concurrency-control max-sessions="1" error-if-maximum-exceeded="true" /> </session-management> </http>
The second login will then be rejected. By "rejected", we mean that the user will be sent to the authentication-failure-url if form-based login is being used. If the second authentication takes place through another non-interactive mechanism, such as "remember-me", an "unauthorized" (401) error will be sent to the client. If instead you want to use an error page, you can add the attribute session-authentication-error-url to the session-management element.
If you are using a customized authentication filter for form-based login, then you have to configure concurrent session control support explicitly. More details can be found in the Session Management chapter.
Session fixation attacks are a potential risk where it is possible for a malicious attacker to create a session by accessing a site, then persuade another user to log in with the same session (by sending them a link containing the session identifier as a parameter, for example). Spring Security protects against this automatically by creating a new session or otherwise changing the session ID when a user logs in. If you don’t require this protection, or it conflicts with some other requirement, you can control the behavior using the session-fixation-protection attribute on <session-management>, which has four options
-
none- Don’t do anything. The original session will be retained. -
newSession- Create a new "clean" session, without copying the existing session data (Spring Security-related attributes will still be copied). -
migrateSession- Create a new session and copy all existing session attributes to the new session. This is the default in Servlet 3.0 or older containers. -
changeSessionId- Do not create a new session. Instead, use the session fixation protection provided by the Servlet container (HttpServletRequest#changeSessionId()). This option is only available in Servlet 3.1 (Java EE 7) and newer containers. Specifying it in older containers will result in an exception. This is the default in Servlet 3.1 and newer containers.
When session fixation protection occurs, it results in a SessionFixationProtectionEvent being published in the application context. If you use changeSessionId, this protection will also result in any javax.servlet.http.HttpSessionIdListener s being notified, so use caution if your code listens for both events. See the Session Management chapter for additional information.
The namespace supports OpenID login either instead of, or in addition to normal form-based login, with a simple change:
<http> <intercept-url pattern="/**" access="ROLE_USER" /> <openid-login /> </http>
You should then register yourself with an OpenID provider (such as myopenid.com), and add the user information to your in-memory <user-service> :
<user name="http://jimi.hendrix.myopenid.com/" authorities="ROLE_USER" />
You should be able to login using the myopenid.com site to authenticate. It is also possible to select a specific UserDetailsService bean for use OpenID by setting the user-service-ref attribute on the openid-login element. See the previous section on authentication providers for more information. Note that we have omitted the password attribute from the above user configuration, since this set of user data is only being used to load the authorities for the user. A random password will be generate internally, preventing you from accidentally using this user data as an authentication source elsewhere in your configuration.
Support for OpenID attribute exchange. As an example, the following configuration would attempt to retrieve the email and full name from the OpenID provider, for use by the application:
<openid-login> <attribute-exchange> <openid-attribute name="email" type="http://axschema.org/contact/email" required="true"/> <openid-attribute name="name" type="http://axschema.org/namePerson"/> </attribute-exchange> </openid-login>
The "type" of each OpenID attribute is a URI, determined by a particular schema, in this case http://axschema.org/. If an attribute must be retrieved for successful authentication, the required attribute can be set. The exact schema and attributes supported will depend on your OpenID provider. The attribute values are returned as part of the authentication process and can be accessed afterwards using the following code:
OpenIDAuthenticationToken token = (OpenIDAuthenticationToken)SecurityContextHolder.getContext().getAuthentication(); List<OpenIDAttribute> attributes = token.getAttributes();
The OpenIDAttribute contains the attribute type and the retrieved value (or values in the case of multi-valued attributes). We’ll see more about how the SecurityContextHolder class is used when we look at core Spring Security components in the technical overview chapter. Multiple attribute exchange configurations are also be supported, if you wish to use multiple identity providers. You can supply multiple attribute-exchange elements, using an identifier-matcher attribute on each. This contains a regular expression which will be matched against the OpenID identifier supplied by the user. See the OpenID sample application in the codebase for an example configuration, providing different attribute lists for the Google, Yahoo and MyOpenID providers.
For additional information on how to customize the headers element refer to the Chapter 20, Security HTTP Response Headers section of the reference.
If you’ve used Spring Security before, you’ll know that the framework maintains a chain of filters in order to apply its services. You may want to add your own filters to the stack at particular locations or use a Spring Security filter for which there isn’t currently a namespace configuration option (CAS, for example). Or you might want to use a customized version of a standard namespace filter, such as the UsernamePasswordAuthenticationFilter which is created by the <form-login> element, taking advantage of some of the extra configuration options which are available by using the bean explicitly. How can you do this with namespace configuration, since the filter chain is not directly exposed?
The order of the filters is always strictly enforced when using the namespace. When the application context is being created, the filter beans are sorted by the namespace handling code and the standard Spring Security filters each have an alias in the namespace and a well-known position.
| Note |
|---|---|
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In previous versions, the sorting took place after the filter instances had been created, during post-processing of the application context. In version 3.0+ the sorting is now done at the bean metadata level, before the classes have been instantiated. This has implications for how you add your own filters to the stack as the entire filter list must be known during the parsing of the |
The filters, aliases and namespace elements/attributes which create the filters are shown in Table 6.1, “Standard Filter Aliases and Ordering”. The filters are listed in the order in which they occur in the filter chain.
Table 6.1. Standard Filter Aliases and Ordering
| Alias | Filter Class | Namespace Element or Attribute |
|---|---|---|
CHANNEL_FILTER |
|
|
SECURITY_CONTEXT_FILTER |
|
|
CONCURRENT_SESSION_FILTER |
|
|
HEADERS_FILTER |
|
|
CSRF_FILTER |
|
|
LOGOUT_FILTER |
|
|
X509_FILTER |
|
|
PRE_AUTH_FILTER |
| N/A |
CAS_FILTER |
| N/A |
FORM_LOGIN_FILTER |
|
|
BASIC_AUTH_FILTER |
|
|
SERVLET_API_SUPPORT_FILTER |
|
|
JAAS_API_SUPPORT_FILTER |
|
|
REMEMBER_ME_FILTER |
|
|
ANONYMOUS_FILTER |
|
|
SESSION_MANAGEMENT_FILTER |
|
|
EXCEPTION_TRANSLATION_FILTER |
|
|
FILTER_SECURITY_INTERCEPTOR |
|
|
SWITCH_USER_FILTER |
| N/A |
You can add your own filter to the stack, using the custom-filter element and one of these names to specify the position your filter should appear at:
<http> <custom-filter position="FORM_LOGIN_FILTER" ref="myFilter" /> </http> <beans:bean id="myFilter" class="com.mycompany.MySpecialAuthenticationFilter"/>
You can also use the after or before attributes if you want your filter to be inserted before or after another filter in the stack. The names "FIRST" and "LAST" can be used with the position attribute to indicate that you want your filter to appear before or after the entire stack, respectively.
![[Tip]](./SpringSecurityReference/tip.png) | Avoiding filter position conflicts |
|---|---|
|
If you are inserting a custom filter which may occupy the same position as one of the standard filters created by the namespace then it’s important that you don’t include the namespace versions by mistake. Remove any elements which create filters whose functionality you want to replace. Note that you can’t replace filters which are created by the use of the |
If you’re replacing a namespace filter which requires an authentication entry point (i.e. where the authentication process is triggered by an attempt by an unauthenticated user to access to a secured resource), you will need to add a custom entry point bean too.
If you aren’t using form login, OpenID or basic authentication through the namespace, you may want to define an authentication filter and entry point using a traditional bean syntax and link them into the namespace, as we’ve just seen. The corresponding AuthenticationEntryPoint can be set using the entry-point-ref attribute on the <http> element.
The CAS sample application is a good example of the use of custom beans with the namespace, including this syntax. If you aren’t familiar with authentication entry points, they are discussed in the technical overview chapter.
From version 2.0 onwards Spring Security has improved support substantially for adding security to your service layer methods. It provides support for JSR-250 annotation security as well as the framework’s original @Secured annotation. From 3.0 you can also make use of new expression-based annotations. You can apply security to a single bean, using the intercept-methods element to decorate the bean declaration, or you can secure multiple beans across the entire service layer using the AspectJ style pointcuts.
This element is used to enable annotation-based security in your application (by setting the appropriate attributes on the element), and also to group together security pointcut declarations which will be applied across your entire application context. You should only declare one <global-method-security> element. The following declaration would enable support for Spring Security’s @Secured:
<global-method-security secured-annotations="enabled" />
Adding an annotation to a method (on an class or interface) would then limit the access to that method accordingly. Spring Security’s native annotation support defines a set of attributes for the method. These will be passed to the AccessDecisionManager for it to make the actual decision:
public interface BankService { @Secured("IS_AUTHENTICATED_ANONYMOUSLY") public Account readAccount(Long id); @Secured("IS_AUTHENTICATED_ANONYMOUSLY") public Account[] findAccounts(); @Secured("ROLE_TELLER") public Account post(Account account, double amount); }
Support for JSR-250 annotations can be enabled using
<global-method-security jsr250-annotations="enabled" />
These are standards-based and allow simple role-based constraints to be applied but do not have the power Spring Security’s native annotations. To use the new expression-based syntax, you would use
<global-method-security pre-post-annotations="enabled" />
and the equivalent Java code would be
public interface BankService { @PreAuthorize("isAnonymous()") public Account readAccount(Long id); @PreAuthorize("isAnonymous()") public Account[] findAccounts(); @PreAuthorize("hasAuthority('ROLE_TELLER')") public Account post(Account account, double amount); }
Expression-based annotations are a good choice if you need to define simple rules that go beyond checking the role names against the user’s list of authorities.
| Note |
|---|---|
|
The annotated methods will only be secured for instances which are defined as Spring beans (in the same application context in which method-security is enabled). If you want to secure instances which are not created by Spring (using the |
| Note |
|---|---|
|
You can enable more than one type of annotation in the same application, but only one type should be used for any interface or class as the behaviour will not be well-defined otherwise. If two annotations are found which apply to a particular method, then only one of them will be applied. |
The use of protect-pointcut is particularly powerful, as it allows you to apply security to many beans with only a simple declaration. Consider the following example:
<global-method-security> <protect-pointcut expression="execution(* com.mycompany.*Service.*(..))" access="ROLE_USER"/> </global-method-security>
This will protect all methods on beans declared in the application context whose classes are in the com.mycompany package and whose class names end in "Service". Only users with the ROLE_USER role will be able to invoke these methods. As with URL matching, the most specific matches must come first in the list of pointcuts, as the first matching expression will be used. Security annotations take precedence over pointcuts.
This section assumes you have some knowledge of the underlying architecture for access-control within Spring Security. If you don’t you can skip it and come back to it later, as this section is only really relevant for people who need to do some customization in order to use more than simple role-based security.
When you use a namespace configuration, a default instance of AccessDecisionManager is automatically registered for you and will be used for making access decisions for method invocations and web URL access, based on the access attributes you specify in your intercept-url and protect-pointcut declarations (and in annotations if you are using annotation secured methods).
The default strategy is to use an AffirmativeBased AccessDecisionManager with a RoleVoter and an AuthenticatedVoter. You can find out more about these in the chapter on authorization.
If you need to use a more complicated access control strategy then it is easy to set an alternative for both method and web security.
For method security, you do this by setting the access-decision-manager-ref attribute on global-method-security to the id of the appropriate AccessDecisionManager bean in the application context:
<global-method-security access-decision-manager-ref="myAccessDecisionManagerBean"> ... </global-method-security>
The syntax for web security is the same, but on the http element:
<http access-decision-manager-ref="myAccessDecisionManagerBean"> ... </http>
The main interface which provides authentication services in Spring Security is the AuthenticationManager. This is usually an instance of Spring Security’s ProviderManager class, which you may already be familiar with if you’ve used the framework before. If not, it will be covered later, in the technical overview chapter. The bean instance is registered using the authentication-manager namespace element. You can’t use a custom AuthenticationManager if you are using either HTTP or method security through the namespace, but this should not be a problem as you have full control over the AuthenticationProvider s that are used.
You may want to register additional AuthenticationProvider beans with the ProviderManager and you can do this using the <authentication-provider> element with the ref attribute, where the value of the attribute is the name of the provider bean you want to add. For example:
<authentication-manager> <authentication-provider ref="casAuthenticationProvider"/> </authentication-manager> <bean id="casAuthenticationProvider" class="org.springframework.security.cas.authentication.CasAuthenticationProvider"> ... </bean>
Another common requirement is that another bean in the context may require a reference to the AuthenticationManager. You can easily register an alias for the AuthenticationManager and use this name elsewhere in your application context.
<security:authentication-manager alias="authenticationManager"> ... </security:authentication-manager> <bean id="customizedFormLoginFilter" class="com.somecompany.security.web.CustomFormLoginFilter"> <property name="authenticationManager" ref="authenticationManager"/> ... </bean>
[1] You can find out more about the use of the ldap-server element in the chapter on Chapter 29, LDAP Authentication.
[2] See the section on Section 13.4, “Request Matching and HttpFirewall” in the Web Application Infrastructure chapter for more details on how matches are actually performed.
[3] See the chapter on Chapter 22, Anonymous Authentication
[4] The use of multiple <http> elements is an important feature, allowing the namespace to simultaneously support both stateful and stateless paths within the same application, for example. The previous syntax, using the attribute filters="none" on an intercept-url element is incompatible with this change and is no longer supported in 3.1.
[5] For more details on how channel-processing is implemented, see the Javadoc for ChannelProcessingFilter and related classes.
There are several sample web applications that are available with the project. To avoid an overly large download, only the "tutorial" and "contacts" samples are included in the distribution zip file. The others can be built directly from the source which you can obtain as described in the introduction. It’s easy to build the project yourself and there’s more information on the project web site at http://spring.io/spring-security/. All paths referred to in this chapter are relative to the project source directory.
The tutorial sample is a nice basic example to get you started. It uses simple namespace configuration throughout. The compiled application is included in the distribution zip file, ready to be deployed into your web container (spring-security-samples-tutorial-3.1.x.war). The form-based authentication mechanism is used in combination with the commonly-used remember-me authentication provider to automatically remember the login using cookies.
We recommend you start with the tutorial sample, as the XML is minimal and easy to follow. Most importantly, you can easily add this one XML file (and its corresponding web.xml entries) to your existing application. Only when this basic integration is achieved do we suggest you attempt adding in method authorization or domain object security.
The Contacts Sample is an advanced example in that it illustrates the more powerful features of domain object access control lists (ACLs) in addition to basic application security. The application provides an interface with which the users are able to administer a simple database of contacts (the domain objects).
To deploy, simply copy the WAR file from Spring Security distribution into your container’s webapps directory. The war should be called spring-security-samples-contacts-3.1.x.war (the appended version number will vary depending on what release you are using).
After starting your container, check the application can load. Visit http://localhost:8080/contacts (or whichever URL is appropriate for your web container and the WAR you deployed).
Next, click "Debug". You will be prompted to authenticate, and a series of usernames and passwords are suggested on that page. Simply authenticate with any of these and view the resulting page. It should contain a success message similar to the following:
Security Debug Information Authentication object is of type: org.springframework.security.authentication.UsernamePasswordAuthenticationToken Authentication object as a String: org.springframework.security.authentication.UsernamePasswordAuthenticationToken@1f127853: Principal: org.springframework.security.core.userdetails.User@b07ed00: Username: rod; \ Password: [PROTECTED]; Enabled: true; AccountNonExpired: true; credentialsNonExpired: true; AccountNonLocked: true; \ Granted Authorities: ROLE_SUPERVISOR, ROLE_USER; \ Password: [PROTECTED]; Authenticated: true; \ Details: org.springframework.security.web.authentication.WebAuthenticationDetails@0: \ RemoteIpAddress: 127.0.0.1; SessionId: 8fkp8t83ohar; \ Granted Authorities: ROLE_SUPERVISOR, ROLE_USER Authentication object holds the following granted authorities: ROLE_SUPERVISOR (getAuthority(): ROLE_SUPERVISOR) ROLE_USER (getAuthority(): ROLE_USER) Success! Your web filters appear to be properly configured!
Once you successfully receive the above message, return to the sample application’s home page and click "Manage". You can then try out the application. Notice that only the contacts available to the currently logged on user are displayed, and only users with ROLE_SUPERVISOR are granted access to delete their contacts. Behind the scenes, the MethodSecurityInterceptor is securing the business objects.
The application allows you to modify the access control lists associated with different contacts. Be sure to give this a try and understand how it works by reviewing the application context XML files.
The LDAP sample application provides a basic configuration and sets up both a namespace configuration and an equivalent configuration using traditional beans, both in the same application context file. This means there are actually two identical authentication providers configured in this application.
The OpenID sample demonstrates how to use the namespace to configure OpenID and how to set up attribute exchange configurations for Google, Yahoo and MyOpenID identity providers (you can experiment with adding others if you wish). It uses the JQuery-based openid-selector project to provide a user-friendly login page which allows the user to easily select a provider, rather than typing in the full OpenID identifier.
The application differs from normal authentication scenarios in that it allows any user to access the site (provided their OpenID authentication is successful). The first time you login, you will get a "Welcome [your name]"" message. If you logout and log back in (with the same OpenID identity) then this should change to "Welcome Back". This is achieved by using a custom UserDetailsService which assigns a standard role to any user and stores the identities internally in a map. Obviously a real application would use a database instead. Have a look at the source form more information. This class also takes into account the fact that different attributes may be returned from different providers and builds the name with which it addresses the user accordingly.
The CAS sample requires that you run both a CAS server and CAS client. It isn’t included in the distribution so you should check out the project code as described in the introduction. You’ll find the relevant files under the sample/cas directory. There’s also a Readme.txt file in there which explains how to run both the server and the client directly from the source tree, complete with SSL support.
The JAAS sample is very simple example of how to use a JAAS LoginModule with Spring Security. The provided LoginModule will successfully authenticate a user if the username equals the password otherwise a LoginException is thrown. The AuthorityGranter used in this example always grants the role ROLE_USER. The sample application also demonstrates how to run as the JAAS Subject returned by the LoginModule by setting jaas-api-provision equal to "true".
This sample application demonstrates how to wire up beans from the pre-authentication framework to make use of login information from a Java EE container. The user name and roles are those setup by the container.
The code is in samples/preauth.
Spring Security uses JIRA to manage bug reports and enhancement requests. If you find a bug, please log a report using JIRA. Do not log it on the support forum, mailing list or by emailing the project’s developers. Such approaches are ad-hoc and we prefer to manage bugs using a more formal process.
If possible, in your issue report please provide a JUnit test that demonstrates any incorrect behaviour. Or, better yet, provide a patch that corrects the issue. Similarly, enhancements are welcome to be logged in the issue tracker, although we only accept enhancement requests if you include corresponding unit tests. This is necessary to ensure project test coverage is adequately maintained.
You can access the issue tracker at https://github.com/spring-projects/spring-security/issues.
We welcome your involvement in the Spring Security project. There are many ways of contributing, including reading the forum and responding to questions from other people, writing new code, improving existing code, assisting with documentation, developing samples or tutorials, or simply making suggestions.
Questions and comments on Spring Security are welcome. You can use the Spring at StackOverflow web site at http://spring.io/questions to discuss Spring Security with other users of the framework. Remember to use JIRA for bug reports, as explained above.
Once you are familiar with setting up and running some namespace-configuration based applications, you may wish to develop more of an understanding of how the framework actually works behind the namespace facade. Like most software, Spring Security has certain central interfaces, classes and conceptual abstractions that are commonly used throughout the framework. In this part of the reference guide we will look at some of these and see how they work together to support authentication and access-control within Spring Security.
Spring Security 3.0 requires a Java 5.0 Runtime Environment or higher. As Spring Security aims to operate in a self-contained manner, there is no need to place any special configuration files into your Java Runtime Environment. In particular, there is no need to configure a special Java Authentication and Authorization Service (JAAS) policy file or place Spring Security into common classpath locations.
Similarly, if you are using an EJB Container or Servlet Container there is no need to put any special configuration files anywhere, nor include Spring Security in a server classloader. All the required files will be contained within your application.
This design offers maximum deployment time flexibility, as you can simply copy your target artifact (be it a JAR, WAR or EAR) from one system to another and it will immediately work.
In Spring Security 3.0, the contents of the spring-security-core jar were stripped down to the bare minimum. It no longer contains any code related to web-application security, LDAP or namespace configuration. We’ll take a look here at some of the Java types that you’ll find in the core module. They represent the building blocks of the framework, so if you ever need to go beyond a simple namespace configuration then it’s important that you understand what they are, even if you don’t actually need to interact with them directly.
The most fundamental object is SecurityContextHolder. This is where we store details of the present security context of the application, which includes details of the principal currently using the application. By default the SecurityContextHolder uses a ThreadLocal to store these details, which means that the security context is always available to methods in the same thread of execution, even if the security context is not explicitly passed around as an argument to those methods. Using a ThreadLocal in this way is quite safe if care is taken to clear the thread after the present principal’s request is processed. Of course, Spring Security takes care of this for you automatically so there is no need to worry about it.
Some applications aren’t entirely suitable for using a ThreadLocal, because of the specific way they work with threads. For example, a Swing client might want all threads in a Java Virtual Machine to use the same security context. SecurityContextHolder can be configured with a strategy on startup to specify how you would like the context to be stored. For a standalone application you would use the SecurityContextHolder.MODE_GLOBAL strategy. Other applications might want to have threads spawned by the secure thread also assume the same security identity. This is achieved by using SecurityContextHolder.MODE_INHERITABLETHREADLOCAL. You can change the mode from the default SecurityContextHolder.MODE_THREADLOCAL in two ways. The first is to set a system property, the second is to call a static method on SecurityContextHolder. Most applications won’t need to change from the default, but if you do, take a look at the JavaDocs for SecurityContextHolder to learn more.
Inside the SecurityContextHolder we store details of the principal currently interacting with the application. Spring Security uses an Authentication object to represent this information. You won’t normally need to create an Authentication object yourself, but it is fairly common for users to query the Authentication object. You can use the following code block - from anywhere in your application - to obtain the name of the currently authenticated user, for example:
Object principal = SecurityContextHolder.getContext().getAuthentication().getPrincipal(); if (principal instanceof UserDetails) { String username = ((UserDetails)principal).getUsername(); } else { String username = principal.toString(); }
The object returned by the call to getContext() is an instance of the SecurityContext interface. This is the object that is kept in thread-local storage. As we’ll see below, most authentication mechanisms withing Spring Security return an instance of UserDetails as the principal.
Another item to note from the above code fragment is that you can obtain a principal from the Authentication object. The principal is just an Object. Most of the time this can be cast into a UserDetails object. UserDetails is a core interface in Spring Security. It represents a principal, but in an extensible and application-specific way. Think of UserDetails as the adapter between your own user database and what Spring Security needs inside the SecurityContextHolder. Being a representation of something from your own user database, quite often you will cast the UserDetails to the original object that your application provided, so you can call business-specific methods (like getEmail(), getEmployeeNumber() and so on).
By now you’re probably wondering, so when do I provide a UserDetails object? How do I do that? I thought you said this thing was declarative and I didn’t need to write any Java code - what gives? The short answer is that there is a special interface called UserDetailsService. The only method on this interface accepts a String-based username argument and returns a UserDetails:
UserDetails loadUserByUsername(String username) throws UsernameNotFoundException;
This is the most common approach to loading information for a user within Spring Security and you will see it used throughout the framework whenever information on a user is required.
On successful authentication, UserDetails is used to build the Authentication object that is stored in the SecurityContextHolder (more on this below). The good news is that we provide a number of UserDetailsService implementations, including one that uses an in-memory map (InMemoryDaoImpl) and another that uses JDBC (JdbcDaoImpl). Most users tend to write their own, though, with their implementations often simply sitting on top of an existing Data Access Object (DAO) that represents their employees, customers, or other users of the application. Remember the advantage that whatever your UserDetailsService returns can always be obtained from the SecurityContextHolder using the above code fragment.
| Note |
|---|---|
|
There is often some confusion about |
Besides the principal, another important method provided by Authentication is getAuthorities(). This method provides an array of GrantedAuthority objects. A GrantedAuthority is, not surprisingly, an authority that is granted to the principal. Such authorities are usually "roles", such as ROLE_ADMINISTRATOR or ROLE_HR_SUPERVISOR. These roles are later on configured for web authorization, method authorization and domain object authorization. Other parts of Spring Security are capable of interpreting these authorities, and expect them to be present. GrantedAuthority objects are usually loaded by the UserDetailsService.
Usually the GrantedAuthority objects are application-wide permissions. They are not specific to a given domain object. Thus, you wouldn’t likely have a GrantedAuthority to represent a permission to Employee object number 54, because if there are thousands of such authorities you would quickly run out of memory (or, at the very least, cause the application to take a long time to authenticate a user). Of course, Spring Security is expressly designed to handle this common requirement, but you’d instead use the project’s domain object security capabilities for this purpose.
Just to recap, the major building blocks of Spring Security that we’ve seen so far are:
-
SecurityContextHolder, to provide access to theSecurityContext. -
SecurityContext, to hold theAuthenticationand possibly request-specific security information. -
Authentication, to represent the principal in a Spring Security-specific manner. -
GrantedAuthority, to reflect the application-wide permissions granted to a principal. -
UserDetails, to provide the necessary information to build an Authentication object from your application’s DAOs or other source of security data. -
UserDetailsService, to create aUserDetailswhen passed in aString-based username (or certificate ID or the like).
Now that you’ve gained an understanding of these repeatedly-used components, let’s take a closer look at the process of authentication.
Spring Security can participate in many different authentication environments. While we recommend people use Spring Security for authentication and not integrate with existing Container Managed Authentication, it is nevertheless supported - as is integrating with your own proprietary authentication system.
Let’s consider a standard authentication scenario that everyone is familiar with.
- A user is prompted to log in with a username and password.
- The system (successfully) verifies that the password is correct for the username.
- The context information for that user is obtained (their list of roles and so on).
- A security context is established for the user
- The user proceeds, potentially to perform some operation which is potentially protected by an access control mechanism which checks the required permissions for the operation against the current security context information.
The first three items constitute the authentication process so we’ll take a look at how these take place within Spring Security.
-
The username and password are obtained and combined into an instance of
UsernamePasswordAuthenticationToken(an instance of theAuthenticationinterface, which we saw earlier). -
The token is passed to an instance of
AuthenticationManagerfor validation. -
The
AuthenticationManagerreturns a fully populatedAuthenticationinstance on successful authentication. -
The security context is established by calling
SecurityContextHolder.getContext().setAuthentication(…), passing in the returned authentication object.
From that point on, the user is considered to be authenticated. Let’s look at some code as an example.
import org.springframework.security.authentication.*; import org.springframework.security.core.*; import org.springframework.security.core.authority.SimpleGrantedAuthority; import org.springframework.security.core.context.SecurityContextHolder; public class AuthenticationExample { private static AuthenticationManager am = new SampleAuthenticationManager(); public static void main(String[] args) throws Exception { BufferedReader in = new BufferedReader(new InputStreamReader(System.in)); while(true) { System.out.println("Please enter your username:"); String name = in.readLine(); System.out.println("Please enter your password:"); String password = in.readLine(); try { Authentication request = new UsernamePasswordAuthenticationToken(name, password); Authentication result = am.authenticate(request); SecurityContextHolder.getContext().setAuthentication(result); break; } catch(AuthenticationException e) { System.out.println("Authentication failed: " + e.getMessage()); } } System.out.println("Successfully authenticated. Security context contains: " + SecurityContextHolder.getContext().getAuthentication()); } } class SampleAuthenticationManager implements AuthenticationManager { static final List<GrantedAuthority> AUTHORITIES = new ArrayList<GrantedAuthority>(); static { AUTHORITIES.add(new SimpleGrantedAuthority("ROLE_USER")); } public Authentication authenticate(Authentication auth) throws AuthenticationException { if (auth.getName().equals(auth.getCredentials())) { return new UsernamePasswordAuthenticationToken(auth.getName(), auth.getCredentials(), AUTHORITIES); } throw new BadCredentialsException("Bad Credentials"); } }
Here
we have written a little program that asks the user to enter a username and password
and performs the above sequence. The
AuthenticationManager which we’ve implemented here will authenticate any user whose username and password are the same. It assigns a single role to every user. The output from the above will be something like:
Please enter your username: bob Please enter your password: password Authentication failed: Bad Credentials Please enter your username: bob Please enter your password: bob Successfully authenticated. Security context contains: \ org.springframework.security.authentication.UsernamePasswordAuthenticationToken@441d0230: \ Principal: bob; Password: [PROTECTED]; \ Authenticated: true; Details: null; \ Granted Authorities: ROLE_USER
Note that you don’t normally need to write any code like this. The process will normally occur internally, in a web authentication filter for example. We’ve just included the code here to show that the question of what actually constitutes authentication in Spring Security has quite a simple answer. A user is authenticated when the SecurityContextHolder contains a fully populated Authentication object.
In fact, Spring Security doesn’t mind how you put the Authentication object inside the SecurityContextHolder. The only critical requirement is that the SecurityContextHolder contains an Authentication which represents a principal before the AbstractSecurityInterceptor (which we’ll see more about later) needs to authorize a user operation.
You can (and many users do) write their own filters or MVC controllers to provide interoperability with authentication systems that are not based on Spring Security. For example, you might be using Container-Managed Authentication which makes the current user available from a ThreadLocal or JNDI location. Or you might work for a company that has a legacy proprietary authentication system, which is a corporate "standard" over which you have little control. In situations like this it’s quite easy to get Spring Security to work, and still provide authorization capabilities. All you need to do is write a filter (or equivalent) that reads the third-party user information from a location, build a Spring Security-specific Authentication object, and put it into the SecurityContextHolder. In this case you also need to think about things which are normally taken care of automatically by the built-in authentication infrastructure. For example, you might need to pre-emptively create an HTTP session to cache the context between requests, before you write the response to the client footnote:[It isn’t possible to create a session once the response has been committed.
If you’re wondering how the AuthenticationManager is implemented in a real world example, we’ll look at that in the core services chapter.
Now let’s explore the situation where you are using Spring Security in a web application (without web.xml security enabled). How is a user authenticated and the security context established?
Consider a typical web application’s authentication process:
- You visit the home page, and click on a link.
- A request goes to the server, and the server decides that you’ve asked for a protected resource.
- As you’re not presently authenticated, the server sends back a response indicating that you must authenticate. The response will either be an HTTP response code, or a redirect to a particular web page.
- Depending on the authentication mechanism, your browser will either redirect to the specific web page so that you can fill out the form, or the browser will somehow retrieve your identity (via a BASIC authentication dialogue box, a cookie, a X.509 certificate etc.).
- The browser will send back a response to the server. This will either be an HTTP POST containing the contents of the form that you filled out, or an HTTP header containing your authentication details.
- Next the server will decide whether or not the presented credentials are valid. If they’re valid, the next step will happen. If they’re invalid, usually your browser will be asked to try again (so you return to step two above).
- The original request that you made to cause the authentication process will be retried. Hopefully you’ve authenticated with sufficient granted authorities to access the protected resource. If you have sufficient access, the request will be successful. Otherwise, you’ll receive back an HTTP error code 403, which means "forbidden".
Spring Security has distinct classes responsible for most of the steps described above. The main participants (in the order that they are used) are the ExceptionTranslationFilter, an AuthenticationEntryPoint and an "authentication mechanism", which is responsible for calling the AuthenticationManager which we saw in the previous section.
ExceptionTranslationFilter is a Spring Security filter that has responsibility for detecting any Spring Security exceptions that are thrown. Such exceptions will generally be thrown by an AbstractSecurityInterceptor, which is the main provider of authorization services. We will discuss AbstractSecurityInterceptor in the next section, but for now we just need to know that it produces Java exceptions and knows nothing about HTTP or how to go about authenticating a principal. Instead the ExceptionTranslationFilter offers this service, with specific responsibility for either returning error code 403 (if the principal has been authenticated and therefore simply lacks sufficient access - as per step seven above), or launching an AuthenticationEntryPoint (if the principal has not been authenticated and therefore we need to go commence step three).
The AuthenticationEntryPoint is responsible for step three in the above list. As you can imagine, each web application will have a default authentication strategy (well, this can be configured like nearly everything else in Spring Security, but let’s keep it simple for now). Each major authentication system will have its own AuthenticationEntryPoint implementation, which typically performs one of the actions described in step 3.
Once your browser submits your authentication credentials (either as an HTTP form post or HTTP header) there needs to be something on the server that"collects" these authentication details. By now we’re at step six in the above list. In Spring Security we have a special name for the function of collecting authentication details from a user agent (usually a web browser), referring to it as the "authentication mechanism". Examples are form-base login and Basic authentication. Once the authentication details have been collected from the user agent, an Authentication "request" object is built and then presented to the AuthenticationManager.
After the authentication mechanism receives back the fully-populated Authentication object, it will deem the request valid, put the Authentication into the SecurityContextHolder, and cause the original request to be retried (step seven above). If, on the other hand, the AuthenticationManager rejected the request, the authentication mechanism will ask the user agent to retry (step two above).
Depending on the type of application, there may need to be a strategy in place to store the security context between user operations. In a typical web application, a user logs in once and is subsequently identified by their session Id. The server caches the principal information for the duration session. In Spring Security, the responsibility for storing the SecurityContext between requests falls to the SecurityContextPersistenceFilter, which by default stores the context as an HttpSession attribute between HTTP requests. It restores the context to the SecurityContextHolder for each request and, crucially, clears the SecurityContextHolder when the request completes. You shouldn’t interact directly with the HttpSession for security purposes. There is simply no justification for doing so - always use the SecurityContextHolder instead.
Many other types of application (for example, a stateless RESTful web service) do not use HTTP sessions and will re-authenticate on every request. However, it is still important that the SecurityContextPersistenceFilter is included in the chain to make sure that the SecurityContextHolder is cleared after each request.
| Note |
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In an application which receives concurrent requests in a single session, the same |
The main interface responsible for making access-control decisions in Spring Security is the AccessDecisionManager. It has a decide method which takes an Authentication object representing the principal requesting access, a "secure object" (see below) and a list of security metadata attributes which apply for the object (such as a list of roles which are required for access to be granted).
If you’re familiar with AOP, you’d be aware there are different types of advice available: before, after, throws and around. An around advice is very useful, because an advisor can elect whether or not to proceed with a method invocation, whether or not to modify the response, and whether or not to throw an exception. Spring Security provides an around advice for method invocations as well as web requests. We achieve an around advice for method invocations using Spring’s standard AOP support and we achieve an around advice for web requests using a standard Filter.
For those not familiar with AOP, the key point to understand is that Spring Security can help you protect method invocations as well as web requests. Most people are interested in securing method invocations on their services layer. This is because the services layer is where most business logic resides in current-generation Java EE applications. If you just need to secure method invocations in the services layer, Spring’s standard AOP will be adequate. If you need to secure domain objects directly, you will likely find that AspectJ is worth considering.
You can elect to perform method authorization using AspectJ or Spring AOP, or you can elect to perform web request authorization using filters. You can use zero, one, two or three of these approaches together. The mainstream usage pattern is to perform some web request authorization, coupled with some Spring AOP method invocation authorization on the services layer.
So what is a "secure object" anyway? Spring Security uses the term to refer to any object that can have security (such as an authorization decision) applied to it. The most common examples are method invocations and web requests.
Each supported secure object type has its own interceptor class, which is a subclass of AbstractSecurityInterceptor. Importantly, by the time the AbstractSecurityInterceptor is called, the SecurityContextHolder will contain a valid Authentication if the principal has been authenticated.
AbstractSecurityInterceptor provides a consistent workflow for handling secure object requests, typically:
- Look up the "configuration attributes" associated with the present request
-
Submitting the secure object, current
Authenticationand configuration attributes to theAccessDecisionManagerfor an authorization decision -
Optionally change the
Authenticationunder which the invocation takes place - Allow the secure object invocation to proceed (assuming access was granted)
-
Call the
AfterInvocationManagerif configured, once the invocation has returned. If the invocation raised an exception, theAfterInvocationManagerwill not be invoked.
A "configuration attribute" can be thought of as a String that has special meaning to the classes used by AbstractSecurityInterceptor. They are represented by the interface ConfigAttribute within the framework. They may be simple role names or have more complex meaning, depending on the how sophisticated the AccessDecisionManager implementation is. The AbstractSecurityInterceptor is configured with a SecurityMetadataSource which it uses to look up the attributes for a secure object. Usually this configuration will be hidden from the user. Configuration attributes will be entered as annotations on secured methods or as access attributes on secured URLs. For example, when we saw something like <intercept-url pattern='/secure/**' access='ROLE_A,ROLE_B'/> in the namespace introduction, this is saying that the configuration attributes ROLE_A and ROLE_B apply to web requests matching the given pattern. In practice, with the default AccessDecisionManager configuration, this means that anyone who has a GrantedAuthority matching either of these two attributes will be allowed access. Strictly speaking though, they are just attributes and the interpretation is dependent on the AccessDecisionManager implementation. The use of the prefix ROLE_ is a marker to indicate that these attributes are roles and should be consumed by Spring Security’s RoleVoter. This is only relevant when a voter-based AccessDecisionManager is in use. We’ll see how the AccessDecisionManager is implemented in the authorization chapter.
Assuming AccessDecisionManager decides to allow the request, the AbstractSecurityInterceptor will normally just proceed with the request. Having said that, on rare occasions users may want to replace the Authentication inside the SecurityContext with a different Authentication, which is handled by the AccessDecisionManager calling a RunAsManager. This might be useful in reasonably unusual situations, such as if a services layer method needs to call a remote system and present a different identity. Because Spring Security automatically propagates security identity from one server to another (assuming you’re using a properly-configured RMI or HttpInvoker remoting protocol client), this may be useful.
Following the secure object invocation proceeding and then returning - which may mean a method invocation completing or a filter chain proceeding - the AbstractSecurityInterceptor gets one final chance to handle the invocation. At this stage the AbstractSecurityInterceptor is interested in possibly modifying the return object. We might want this to happen because an authorization decision couldn’t be made "on the way in" to a secure object invocation. Being highly pluggable, AbstractSecurityInterceptor will pass control to an AfterInvocationManager to actually modify the object if needed. This class can even entirely replace the object, or throw an exception, or not change it in any way as it chooses. The after-invocation checks will only be executed if the invocation is successful. If an exception occurs, the additional checks will be skipped.
AbstractSecurityInterceptor and its related objects are shown in Figure 9.1, “Security interceptors and the "secure object" model”
Only developers contemplating an entirely new way of intercepting and authorizing requests would need to use secure objects directly. For example, it would be possible to build a new secure object to secure calls to a messaging system. Anything that requires security and also provides a way of intercepting a call (like the AOP around advice semantics) is capable of being made into a secure object. Having said that, most Spring applications will simply use the three currently supported secure object types (AOP Alliance MethodInvocation, AspectJ JoinPoint and web request FilterInvocation) with complete transparency.
Spring Security supports localization of exception messages that end users are likely to see. If your application is designed for English-speaking users, you don’t need to do anything as by default all Security messages are in English. If you need to support other locales, everything you need to know is contained in this section.
All exception messages can be localized, including messages related to authentication failures and access being denied (authorization failures). Exceptions and logging messages that are focused on developers or system deployers (including incorrect attributes, interface contract violations, using incorrect constructors, startup time validation, debug-level logging) are not localized and instead are hard-coded in English within Spring Security’s code.
Shipping in the spring-security-core-xx.jar you will find an org.springframework.security package that in turn contains a messages.properties file, as well as localized versions for some common languages. This should be referred to by your ApplicationContext, as Spring Security classes implement Spring’s MessageSourceAware interface and expect the message resolver to be dependency injected at application context startup time. Usually all you need to do is register a bean inside your application context to refer to the messages. An example is shown below:
<bean id="messageSource" class="org.springframework.context.support.ReloadableResourceBundleMessageSource"> <property name="basename" value="classpath:org/springframework/security/messages"/> </bean>
The messages.properties is named in accordance with standard resource bundles and represents the default language supported by Spring Security messages. This default file is in English.
If you wish to customize the messages.properties file, or support other languages, you should copy the file, rename it accordingly, and register it inside the above bean definition. There are not a large number of message keys inside this file, so localization should not be considered a major initiative. If you do perform localization of this file, please consider sharing your work with the community by logging a JIRA task and attaching your appropriately-named localized version of messages.properties.
Spring Security relies on Spring’s localization support in order to actually lookup the appropriate message. In order for this to work, you have to make sure that the locale from the incoming request is stored in Spring’s org.springframework.context.i18n.LocaleContextHolder. Spring MVC’s DispatcherServlet does this for your application automatically, but since Spring Security’s filters are invoked before this, the LocaleContextHolder needs to be set up to contain the correct Locale before the filters are called. You can either do this in a filter yourself (which must come before the Spring Security filters in web.xml) or you can use Spring’s RequestContextFilter. Please refer to the Spring Framework documentation for further details on using localization with Spring.
The "contacts" sample application is set up to use localized messages.
Now that we have a high-level overview of the Spring Security architecture and its core classes, let’s take a closer look at one or two of the core interfaces and their implementations, in particular the AuthenticationManager, UserDetailsService and the AccessDecisionManager. These crop up regularly throughout the remainder of this document so it’s important you know how they are configured and how they operate.
The AuthenticationManager is just an interface, so the implementation can be anything we choose, but how does it work in practice? What if we need to check multiple authentication databases or a combination of different authentication services such as a database and an LDAP server?
The default implementation in Spring Security is called ProviderManager and rather than handling the authentication request itself, it delegates to a list of configured AuthenticationProvider s, each of which is queried in turn to see if it can perform the authentication. Each provider will either throw an exception or return a fully populated Authentication object. Remember our good friends, UserDetails and UserDetailsService? If not, head back to the previous chapter and refresh your memory. The most common approach to verifying an authentication request is to load the corresponding UserDetails and check the loaded password against the one that has been entered by the user. This is the approach used by the DaoAuthenticationProvider (see below). The loaded UserDetails object - and particularly the GrantedAuthority s it contains - will be used when building the fully populated Authentication object which is returned from a successful authentication and stored in the SecurityContext.
If you are using the namespace, an instance of ProviderManager is created and maintained internally, and you add providers to it by using the namespace authentication provider elements (see the namespace chapter). In this case, you should not declare a ProviderManager bean in your application context. However, if you are not using the namespace then you would declare it like so:
<bean id="authenticationManager" class="org.springframework.security.authentication.ProviderManager"> <constructor-arg> <list> <ref local="daoAuthenticationProvider"/> <ref local="anonymousAuthenticationProvider"/> <ref local="ldapAuthenticationProvider"/> </list> </constructor-arg> </bean>
In the above example we have three providers. They are tried in the order shown (which is implied by the use of a List), with each provider able to attempt authentication, or skip authentication by simply returning null. If all implementations return null, the ProviderManager will throw a ProviderNotFoundException. If you’re interested in learning more about chaining providers, please refer to the ProviderManager JavaDocs.
Authentication mechanisms such as a web form-login processing filter are injected with a reference to the ProviderManager and will call it to handle their authentication requests. The providers you require will sometimes be interchangeable with the authentication mechanisms, while at other times they will depend on a specific authentication mechanism. For example, DaoAuthenticationProvider and LdapAuthenticationProvider are compatible with any mechanism which submits a simple username/password authentication request and so will work with form-based logins or HTTP Basic authentication. On the other hand, some authentication mechanisms create an authentication request object which can only be interpreted by a single type of AuthenticationProvider. An example of this would be JA-SIG CAS, which uses the notion of a service ticket and so can therefore only be authenticated by a CasAuthenticationProvider. You needn’t be too concerned about this, because if you forget to register a suitable provider, you’ll simply receive a ProviderNotFoundException when an attempt to authenticate is made.
By default (from Spring Security 3.1 onwards) the ProviderManager will attempt to clear any sensitive credentials information from the Authentication object which is returned by a successful authentication request. This prevents information like passwords being retained longer than necessary.
This may cause issues when you are using a cache of user objects, for example, to improve performance in a stateless application. If the Authentication contains a reference to an object in the cache (such as a UserDetails instance) and this has its credentials removed, then it will no longer be possible to authenticate against the cached value. You need to take this into account if you are using a cache. An obvious solution is to make a copy of the object first, either in the cache implementation or in the AuthenticationProvider which creates the returned Authentication object. Alternatively, you can disable the eraseCredentialsAfterAuthentication property on ProviderManager. See the Javadoc for more information.
The simplest AuthenticationProvider implemented by Spring Security is DaoAuthenticationProvider, which is also one of the earliest supported by the framework. It leverages a UserDetailsService (as a DAO) in order to lookup the username, password and GrantedAuthority s. It authenticates the user simply by comparing the password submitted in a UsernamePasswordAuthenticationToken against the one loaded by the UserDetailsService. Configuring the provider is quite simple:
<bean id="daoAuthenticationProvider" class="org.springframework.security.authentication.dao.DaoAuthenticationProvider"> <property name="userDetailsService" ref="inMemoryDaoImpl"/> <property name="passwordEncoder" ref="passwordEncoder"/> </bean>
The PasswordEncoder is optional. A PasswordEncoder provides encoding and decoding of passwords presented in the UserDetails object that is returned from the configured UserDetailsService. This will be discussed in more detail below.
As mentioned in the earlier in this reference guide, most authentication providers take advantage of the UserDetails and UserDetailsService interfaces. Recall that the contract for UserDetailsService is a single method:
UserDetails loadUserByUsername(String username) throws UsernameNotFoundException;
The returned UserDetails is an interface that provides getters that guarantee non-null provision of authentication information such as the username, password, granted authorities and whether the user account is enabled or disabled. Most authentication providers will use a UserDetailsService, even if the username and password are not actually used as part of the authentication decision. They may use the returned UserDetails object just for its GrantedAuthority information, because some other system (like LDAP or X.509 or CAS etc) has undertaken the responsibility of actually validating the credentials.
Given UserDetailsService is so simple to implement, it should be easy for users to retrieve authentication information using a persistence strategy of their choice. Having said that, Spring Security does include a couple of useful base implementations, which we’ll look at below.
Is easy to use create a custom UserDetailsService implementation that extracts information from a persistence engine of choice, but many applications do not require such complexity. This is particularly true if you’re building a prototype application or just starting integrating Spring Security, when you don’t really want to spend time configuring databases or writing UserDetailsService implementations. For this sort of situation, a simple option is to use the user-service element from the security namespace:
<user-service id="userDetailsService"> <user name="jimi" password="jimispassword" authorities="ROLE_USER, ROLE_ADMIN" /> <user name="bob" password="bobspassword" authorities="ROLE_USER" /> </user-service>
This also supports the use of an external properties file:
<user-service id="userDetailsService" properties="users.properties"/>
The properties file should contain entries in the form
username=password,grantedAuthority[,grantedAuthority][,enabled|disabled]
For example
jimi=jimispassword,ROLE_USER,ROLE_ADMIN,enabled bob=bobspassword,ROLE_USER,enabled
Spring Security also includes a UserDetailsService that can obtain authentication information from a JDBC data source. Internally Spring JDBC is used, so it avoids the complexity of a fully-featured object relational mapper (ORM) just to store user details. If your application does use an ORM tool, you might prefer to write a custom UserDetailsService to reuse the mapping files you’ve probably already created. Returning to JdbcDaoImpl, an example configuration is shown below:
<bean id="dataSource" class="org.springframework.jdbc.datasource.DriverManagerDataSource"> <property name="driverClassName" value="org.hsqldb.jdbcDriver"/> <property name="url" value="jdbc:hsqldb:hsql://localhost:9001"/> <property name="username" value="sa"/> <property name="password" value=""/> </bean> <bean id="userDetailsService" class="org.springframework.security.core.userdetails.jdbc.JdbcDaoImpl"> <property name="dataSource" ref="dataSource"/> </bean>
You can use different relational database management systems by modifying the DriverManagerDataSource shown above. You can also use a global data source obtained from JNDI, as with any other Spring configuration.
By default, JdbcDaoImpl loads the authorities for a single user with the assumption that the authorities are mapped directly to users (see the database schema appendix). An alternative approach is to partition the authorities into groups and assign groups to the user. Some people prefer this approach as a means of administering user rights. See the JdbcDaoImpl Javadoc for more information on how to enable the use of group authorities. The group schema is also included in the appendix.
Spring Security’s PasswordEncoder interface is used to support the use of passwords which are encoded in some way in persistent storage. You should never store passwords in plain text. Always use a one-way password hashing algorithm such as bcrypt which uses a built-in salt value which is different for each stored password. Do not use a plain hash function such as MD5 or SHA, or even a salted version. Bcrypt is deliberately designed to be slow and to hinder offline password cracking, whereas standard hash algorithms are fast and can easily be used to test thousands of passwords in parallel on custom hardware. You might think this doesn’t apply to you since your password database is secure and offline attacks aren’t a risk. If so, do some research and read up on all the high-profile sites which have been compromised in this way and have been pilloried for storing their passwords insecurely. It’s best to be on the safe side. Using org.springframework.security.crypto.bcrypt.BCryptPasswordEncoder" is a good choice for security. There are also compatible implementations in other common programming languages so it a good choice for interoperability too.
If you are using a legacy system which already has hashed passwords, then you will need to use an encoder which matches your current algorithm, at least until you can migrate your users to a more secure scheme (usually this will involve asking the user to set a new password, since hashes are irreversible). Spring Security has a package containing legacy password encoding implementation, namely, org.springframework.security.authentication.encoding. The DaoAuthenticationProvider can be injected with either the new or legacy PasswordEncoder types.
Password hashing is not unique to Spring Security but is a common source of confusion for users who are not familiar with the concept. A hash (or digest) algorithm is a one-way function which produces a piece of fixed-length output data (the hash) from some input data, such as a password. As an example, the MD5 hash of the string "password" (in hexadecimal) is
5f4dcc3b5aa765d61d8327deb882cf99
A hash is "one-way" in the sense that it is very difficult (effectively impossible) to obtain the original input given the hash value, or indeed any possible input which would produce that hash value. This property makes hash values very useful for authentication purposes. They can be stored in your user database as an alternative to plaintext passwords and even if the values are compromised they do not immediately reveal a password which can be used to login. Note that this also means you have no way of recovering the password once it is encoded.
One potential problem with the use of password hashes that it is relatively easy to get round the one-way property of the hash if a common word is used for the input. People tend to choose similar passwords and huge dictionaries of these from previously hacked sites are available online. For example, if you search for the hash value 5f4dcc3b5aa765d61d8327deb882cf99 using google, you will quickly find the original word "password". In a similar way, an attacker can build a dictionary of hashes from a standard word list and use this to lookup the original password. One way to help prevent this is to have a suitably strong password policy to try to prevent common words from being used. Another is to use a"salt" when calculating the hashes. This is an additional string of known data for each user which is combined with the password before calculating the hash. Ideally the data should be as random as possible, but in practice any salt value is usually preferable to none. Using a salt means that an attacker has to build a separate dictionary of hashes for each salt value, making the attack more complicated (but not impossible).
Bcrypt automatically generates a random salt value for each password when it is encoded, and stores it in the bcrypt string in a standard format.
| Note |
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The legacy approach to handling salt was to inject a |
When an authentication provider (such as Spring Security’s DaoAuthenticationProvider) needs to check the password in a submitted authentication request against the known value for a user, and the stored password is encoded in some way, then the submitted value must be encoded using exactly the same algorithm. It’s up to you to check that these are compatible as Spring Security has no control over the persistent values. If you add password hashing to your authentication configuration in Spring Security, and your database contains plaintext passwords, then there is no way authentication can succeed. Even if you are aware that your database is using MD5 to encode the passwords, for example, and your application is configured to use Spring Security’s Md5PasswordEncoder, there are still things that can go wrong. The database may have the passwords encoded in Base 64, for example while the encoder is using hexadecimal strings (the default). Alternatively your database may be using upper-case while the output from the encoder is lower-case. Make sure you write a test to check the output from your configured password encoder with a known password and salt combination and check that it matches the database value before going further and attempting to authenticate through your application. Using a standard like bcrypt will avoid these issues.
If you want to generate encoded passwords directly in Java for storage in your user database, then you can use the encode method on the PasswordEncoder.
This section describes the testing support provided by Spring Security.
| Tip |
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To use the Spring Security test support, you must include |
This section demonstrates how to use Spring Security’s Test support to test method based security.
We first introduce a MessageService that requires the user to be authenticated in order to access it.
public class HelloMessageService implements MessageService { @PreAuthorize("authenticated") public String getMessage() { Authentication authentication = SecurityContextHolder.getContext() .getAuthentication(); return "Hello " + authentication; } }
The result of getMessage is a String saying "Hello" to the current Spring Security Authentication.
An example of the output is displayed below.
Hello org.springframework.security.authentication.UsernamePasswordAuthenticationToken@ca25360: Principal: org.springframework.security.core.userdetails.User@36ebcb: Username: user; Password: [PROTECTED]; Enabled: true; AccountNonExpired: true; credentialsNonExpired: true; AccountNonLocked: true; Granted Authorities: ROLE_USER; Credentials: [PROTECTED]; Authenticated: true; Details: null; Granted Authorities: ROLE_USER
Before we can use Spring Security Test support, we must perform some setup. An example can be seen below:
@RunWith(SpringJUnit4ClassRunner.class)
This is a basic example of how to setup Spring Security Test. The highlights are:
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Spring Security hooks into Spring Test support using the |
Remember we added the @PreAuthorize annotation to our HelloMessageService and so it requires an authenticated user to invoke it.
If we ran the following test, we would expect the following test will pass:
@Test(expected = AuthenticationCredentialsNotFoundException.class) public void getMessageUnauthenticated() { messageService.getMessage(); }
The question is "How could we most easily run the test as a specific user?"
The answer is to use @WithMockUser.
The following test will be ran as a user with the username "user", the password "password", and the roles "ROLE_USER".
@Test @WithMockUser public void getMessageWithMockUser() { String message = messageService.getMessage(); ... }
Specifically the following is true:
- The user with the username "user" does not have to exist since we are mocking the user
-
The
Authenticationthat is populated in theSecurityContextis of typeUsernamePasswordAuthenticationToken -
The principal on the
Authenticationis Spring Security’sUserobject -
The
Userwill have the username of "user", the password "password", and a singleGrantedAuthoritynamed "ROLE_USER" is used.
Our example is nice because we are able to leverage a lot of defaults. What if we wanted to run the test with a different username? The following test would run with the username "customUser". Again, the user does not need to actually exist.
@Test @WithMockUser("customUsername") public void getMessageWithMockUserCustomUsername() { String message = messageService.getMessage(); ... }
We can also easily customize the roles. For example, this test will be invoked with the username "admin" and the roles "ROLE_USER" and "ROLE_ADMIN".
@Test @WithMockUser(username="admin",roles={"USER","ADMIN"}) public void getMessageWithMockUserCustomUser() { String message = messageService.getMessage(); ... }
If we do not want the value to automatically be prefixed with ROLE_ we can leverage the authorities attribute. For example, this test will be invoked with the username "admin" and the authorities "USER" and "ADMIN".
@Test @WithMockUser(username = "admin", authorities = { "ADMIN", "USER" }) public void getMessageWithMockUserCustomAuthorities() { String message = messageService.getMessage(); ... }
Of course it can be a bit tedious placing the annotation on every test method. Instead, we can place the annotation at the class level and every test will use the specified user. For example, the following would run every test with a user with the username "admin", the password "password", and the roles "ROLE_USER" and "ROLE_ADMIN".
@RunWith(SpringJUnit4ClassRunner.class) @ContextConfiguration @WithMockUser(username="admin",roles={"USER","ADMIN"}) public class WithMockUserTests {
Using @WithAnonymousUser allows running as an anonymous user.
This is especially convenient when you wish to run most of your tests with a specific user, but want to run a few tests as an anonymous user.
For example, the following will run withMockUser1 and withMockUser2 using @WithMockUser and anonymous as an anonymous user.
@RunWith(SpringJUnit4ClassRunner.class) @WithMockUser public class WithUserClassLevelAuthenticationTests { @Test public void withMockUser1() { } @Test public void withMockUser2() { } @Test @WithAnonymousUser public void anonymous() throws Exception { // override default to run as anonymous user } }
While @WithMockUser is a very convenient way to get started, it may not work in all instances.
For example, it is common for applications to expect that the Authentication principal be of a specific type.
This is done so that the application can refer to the principal as the custom type and reduce coupling on Spring Security.
The custom principal is often times returned by a custom UserDetailsService that returns an object that implements both UserDetails and the custom type.
For situations like this, it is useful to create the test user using the custom UserDetailsService.
That is exactly what @WithUserDetails does.
Assuming we have a UserDetailsService exposed as a bean, the following test will be invoked with an Authentication of type UsernamePasswordAuthenticationToken and a principal that is returned from the UserDetailsService with the username of "user".
@Test @WithUserDetails public void getMessageWithUserDetails() { String message = messageService.getMessage(); ... }
We can also customize the username used to lookup the user from our UserDetailsService.
For example, this test would be executed with a principal that is returned from the UserDetailsService with the username of "customUsername".
@Test @WithUserDetails("customUsername") public void getMessageWithUserDetailsCustomUsername() { String message = messageService.getMessage(); ... }
We can also provide an explicit bean name to look up the UserDetailsService.
For example, this test would look up the username of "customUsername" using the UserDetailsService with the bean name "myUserDetailsService".
@Test @WithUserDetails(value="customUsername", userDetailsServiceBeanName="myUserDetailsService") public void getMessageWithUserDetailsServiceBeanName() { String message = messageService.getMessage(); ... }
Like @WithMockUser we can also place our annotation at the class level so that every test uses the same user.
However unlike @WithMockUser, @WithUserDetails requires the user to exist.
We have seen that @WithMockUser is an excellent choice if we are not using a custom Authentication principal.
Next we discovered that @WithUserDetails would allow us to use a custom UserDetailsService to create our Authentication principal but required the user to exist.
We will now see an option that allows the most flexibility.
We can create our own annotation that uses the @WithSecurityContext to create any SecurityContext we want.
For example, we might create an annotation named @WithMockCustomUser as shown below:
@Retention(RetentionPolicy.RUNTIME) @WithSecurityContext(factory = WithMockCustomUserSecurityContextFactory.class) public @interface WithMockCustomUser { String username() default "rob"; String name() default "Rob Winch"; }
You can see that @WithMockCustomUser is annotated with the @WithSecurityContext annotation.
This is what signals to Spring Security Test support that we intend to create a SecurityContext for the test.
The @WithSecurityContext annotation requires we specify a SecurityContextFactory that will create a new SecurityContext given our @WithMockCustomUser annotation.
You can find our WithMockCustomUserSecurityContextFactory implementation below:
public class WithMockCustomUserSecurityContextFactory implements WithSecurityContextFactory<WithMockCustomUser> { @Override public SecurityContext createSecurityContext(WithMockCustomUser customUser) { SecurityContext context = SecurityContextHolder.createEmptyContext(); CustomUserDetails principal = new CustomUserDetails(customUser.name(), customUser.username()); Authentication auth = new UsernamePasswordAuthenticationToken(principal, "password", principal.getAuthorities()); context.setAuthentication(auth); return context; } }
We can now annotate a test class or a test method with our new annotation and Spring Security’s WithSecurityContextTestExecutionListener will ensure that our SecurityContext is populated appropriately.
When creating your own WithSecurityContextFactory implementations, it is nice to know that they can be annotated with standard Spring annotations.
For example, the WithUserDetailsSecurityContextFactory uses the @Autowired annotation to acquire the UserDetailsService:
final class WithUserDetailsSecurityContextFactory implements WithSecurityContextFactory<WithUserDetails> { private UserDetailsService userDetailsService; @Autowired public WithUserDetailsSecurityContextFactory(UserDetailsService userDetailsService) { this.userDetailsService = userDetailsService; } public SecurityContext createSecurityContext(WithUserDetails withUser) { String username = withUser.value(); Assert.hasLength(username, "value() must be non empty String"); UserDetails principal = userDetailsService.loadUserByUsername(username); Authentication authentication = new UsernamePasswordAuthenticationToken(principal, principal.getPassword(), principal.getAuthorities()); SecurityContext context = SecurityContextHolder.createEmptyContext(); context.setAuthentication(authentication); return context; } }
If you reuse the same user within your tests often, it is not ideal to have to repeatedly specify the attributes.
For example, if there are many tests related to an administrative user with the username "admin" and the roles ROLE_USER and ROLE_ADMIN you would have to write:
@WithMockUser(username="admin",roles={"USER","ADMIN"})
Rather than repeating this everywhere, we can use a meta annotation.
For example, we could create a meta annotation named WithMockAdmin:
@Retention(RetentionPolicy.RUNTIME) @WithMockUser(value="rob",roles="ADMIN") public @interface WithMockAdmin { }
Now we can use @WithMockAdmin in the same way as the more verbose @WithMockUser.
Meta annotations work with any of the testing annotations described above.
For example, this means we could create a meta annotation for @WithUserDetails("admin") as well.
Spring Security provides comprehensive integration with Spring MVC Test
In order to use Spring Security with Spring MVC Test it is necessary to add the Spring Security FilterChainProxy as a Filter.
It is also necessary to add Spring Security’s TestSecurityContextHolderPostProcessor to support Running as a User in Spring MVC Test with Annotations.
This can be done using Spring Security’s SecurityMockMvcConfigurers.springSecurity().
For example:
| Note |
|---|---|
|
Spring Security’s testing support requires spring-test-4.1.3.RELEASE or greater. |
import static org.springframework.security.test.web.servlet.setup.SecurityMockMvcConfigurers.*; @RunWith(SpringJUnit4ClassRunner.class) @ContextConfiguration @WebAppConfiguration public class CsrfShowcaseTests { @Autowired private WebApplicationContext context; private MockMvc mvc; @Before public void setup() { mvc = MockMvcBuilders .webAppContextSetup(context) .apply(springSecurity())
|
|
Spring MVC Test provides a convenient interface called a RequestPostProcessor that can be used to modify a request.
Spring Security provides a number of RequestPostProcessor implementations that make testing easier.
In order to use Spring Security’s RequestPostProcessor implementations ensure the following static import is used:
import static org.springframework.security.test.web.servlet.request.SecurityMockMvcRequestPostProcessors.*;
When testing any non safe HTTP methods and using Spring Security’s CSRF protection, you must be sure to include a valid CSRF Token in the request. To specify a valid CSRF token as a request parameter using the following:
mvc
.perform(post("/").with(csrf()))
If you like you can include CSRF token in the header instead:
mvc
.perform(post("/").with(csrf().asHeader()))
You can also test providing an invalid CSRF token using the following:
mvc
.perform(post("/").with(csrf().useInvalidToken()))
It is often desirable to run tests as a specific user. There are two simple ways of populating the user:
There are a number of options available to associate a user to the current HttpServletRequest.
For example, the following will run as a user (which does not need to exist) with the username "user", the password "password", and the role "ROLE_USER":
| Note |
|---|---|
|
The support works by associating the user to the
|
mvc .perform(get("/").with(user("user")))
You can easily make customizations. For example, the following will run as a user (which does not need to exist) with the username "admin", the password "pass", and the roles "ROLE_USER" and "ROLE_ADMIN".
mvc .perform(get("/admin").with(user("admin").password("pass").roles("USER","ADMIN")))
If you have a custom UserDetails that you would like to use, you can easily specify that as well.
For example, the following will use the specified UserDetails (which does not need to exist) to run with a UsernamePasswordAuthenticationToken that has a principal of the specified UserDetails:
mvc
.perform(get("/").with(user(userDetails)))
You can run as anonymous user using the following:
mvc
.perform(get("/").with(anonymous()))
This is especially useful if you are running with a default user and wish to execute a few requests as an anonymous user.
If you want a custom Authentication (which does not need to exist) you can do so using the following:
mvc
.perform(get("/").with(authentication(authentication)))
You can even customize the SecurityContext using the following:
mvc
.perform(get("/").with(securityContext(securityContext)))
We can also ensure to run as a specific user for every request by using MockMvcBuilders's default request.
For example, the following will run as a user (which does not need to exist) with the username "admin", the password "password", and the role "ROLE_ADMIN":
mvc = MockMvcBuilders .webAppContextSetup(context) .defaultRequest(get("/").with(user("user").roles("ADMIN"))) .apply(springSecurity()) .build();
If you find you are using the same user in many of your tests, it is recommended to move the user to a method.
For example, you can specify the following in your own class named CustomSecurityMockMvcRequestPostProcessors:
public static RequestPostProcessor rob() { return user("rob").roles("ADMIN"); }
Now you can perform a static import on SecurityMockMvcRequestPostProcessors and use that within your tests:
import static sample.CustomSecurityMockMvcRequestPostProcessors.*; ... mvc .perform(get("/").with(rob()))
As an alternative to using a RequestPostProcessor to create your user, you can use annotations described in Chapter 11, Testing Method Security.
For example, the following will run the test with the user with username "user", password "password", and role "ROLE_USER":
@Test @WithMockUser public void requestProtectedUrlWithUser() throws Exception { mvc .perform(get("/")) ... }
Alternatively, the following will run the test with the user with username "user", password "password", and role "ROLE_ADMIN":
@Test @WithMockUser(roles="ADMIN") public void requestProtectedUrlWithUser() throws Exception { mvc .perform(get("/")) ... }
While it has always been possible to authenticate with HTTP Basic, it was a bit tedious to remember the header name, format, and encode the values.
Now this can be done using Spring Security’s httpBasic RequestPostProcessor.
For example, the snippet below:
mvc .perform(get("/").with(httpBasic("user","password")))
will attempt to use HTTP Basic to authenticate a user with the username "user" and the password "password" by ensuring the following header is populated on the HTTP Request:
Authorization: Basic dXNlcjpwYXNzd29yZA==
Spring MVC Test also provides a RequestBuilder interface that can be used to create the MockHttpServletRequest used in your test.
Spring Security provides a few RequestBuilder implementations that can be used to make testing easier.
In order to use Spring Security’s RequestBuilder implementations ensure the following static import is used:
import static org.springframework.security.test.web.servlet.request.SecurityMockMvcRequestBuilders.*;
You can easily create a request to test a form based authentication using Spring Security’s testing support. For example, the following will submit a POST to "/login" with the username "user", the password "password", and a valid CSRF token:
mvc .perform(formLogin())
It is easy to customize the request. For example, the following will submit a POST to "/auth" with the username "admin", the password "pass", and a valid CSRF token:
mvc .perform(formLogin("/auth").user("admin").password("pass"))
We can also customize the parameters names that the username and password are included on. For example, this is the above request modified to include the username on the HTTP parameter "u" and the password on the HTTP parameter "p".
mvc .perform(formLogin("/auth").user("u","admin").password("p","pass"))
While fairly trivial using standard Spring MVC Test, you can use Spring Security’s testing support to make testing log out easier. For example, the following will submit a POST to "/logout" with a valid CSRF token:
mvc .perform(logout())
You can also customize the URL to post to. For example, the snippet below will submit a POST to "/signout" with a valid CSRF token:
mvc
.perform(logout("/signout"))
At times it is desirable to make various security related assertions about a request.
To accommodate this need, Spring Security Test support implements Spring MVC Test’s ResultMatcher interface.
In order to use Spring Security’s ResultMatcher implementations ensure the following static import is used:
import static org.springframework.security.test.web.servlet.response.SecurityMockMvcResultMatchers.*;
At times it may be valuable to assert that there is no authenticated user associated with the result of a MockMvc invocation.
For example, you might want to test submitting an invalid username and password and verify that no user is authenticated.
You can easily do this with Spring Security’s testing support using something like the following:
mvc
.perform(formLogin().password("invalid"))
.andExpect(unauthenticated());
It is often times that we must assert that an authenticated user exists. For example, we may want to verify that we authenticated successfully. We could verify that a form based login was successful with the following snippet of code:
mvc .perform(formLogin()) .andExpect(authenticated());
If we wanted to assert the roles of the user, we could refine our previous code as shown below:
mvc .perform(formLogin().user("admin")) .andExpect(authenticated().withRoles("USER","ADMIN"));
Alternatively, we could verify the username:
mvc .perform(formLogin().user("admin")) .andExpect(authenticated().withUsername("admin"));
We can also combine the assertions:
mvc .perform(formLogin().user("admin").roles("USER","ADMIN")) .andExpect(authenticated().withUsername("admin"));
Most Spring Security users will be using the framework in applications which make user of HTTP and the Servlet API. In this part, we’ll take a look at how Spring Security provides authentication and access-control features for the web layer of an application. We’ll look behind the facade of the namespace and see which classes and interfaces are actually assembled to provide web-layer security. In some situations it is necessary to use traditional bean configuration to provide full control over the configuration, so we’ll also see how to configure these classes directly without the namespace.
Spring Security’s web infrastructure is based entirely on standard servlet filters. It doesn’t use servlets or any other servlet-based frameworks (such as Spring MVC) internally, so it has no strong links to any particular web technology. It deals in HttpServletRequest s and HttpServletResponse s and doesn’t care whether the requests come from a browser, a web service client, an HttpInvoker or an AJAX application.
Spring Security maintains a filter chain internally where each of the filters has a particular responsibility and filters are added or removed from the configuration depending on which services are required. The ordering of the filters is important as there are dependencies between them. If you have been using namespace configuration, then the filters are automatically configured for you and you don’t have to define any Spring beans explicitly but here may be times when you want full control over the security filter chain, either because you are using features which aren’t supported in the namespace, or you are using your own customized versions of classes.
When using servlet filters, you obviously need to declare them in your web.xml, or they will be ignored by the servlet container. In Spring Security, the filter classes are also Spring beans defined in the application context and thus able to take advantage of Spring’s rich dependency-injection facilities and lifecycle interfaces. Spring’s DelegatingFilterProxy provides the link between web.xml and the application context.
When using DelegatingFilterProxy, you will see something like this in the web.xml file:
<filter> <filter-name>myFilter</filter-name> <filter-class>org.springframework.web.filter.DelegatingFilterProxy</filter-class> </filter> <filter-mapping> <filter-name>myFilter</filter-name> <url-pattern>/*</url-pattern> </filter-mapping>
Notice that the filter is actually a DelegatingFilterProxy, and not the class that will actually implement the logic of the filter. What DelegatingFilterProxy does is delegate the Filter 's methods through to a bean which is obtained from the Spring application context. This enables the bean to benefit from the Spring web application context lifecycle support and configuration flexibility. The bean must implement javax.servlet.Filter and it must have the same name as that in the filter-name element. Read the Javadoc for DelegatingFilterProxy for more information
Spring Security’s web infrastructure should only be used by delegating to an instance of FilterChainProxy. The security filters should not be used by themselves. In theory you could declare each Spring Security filter bean that you require in your application context file and add a corresponding DelegatingFilterProxy entry to web.xml for each filter, making sure that they are ordered correctly, but this would be cumbersome and would clutter up the web.xml file quickly if you have a lot of filters. FilterChainProxy lets us add a single entry to web.xml and deal entirely with the application context file for managing our web security beans. It is wired using a DelegatingFilterProxy, just like in the example above, but with the filter-name set to the bean name "filterChainProxy". The filter chain is then declared in the application context with the same bean name. Here’s an example:
<bean id="filterChainProxy" class="org.springframework.security.web.FilterChainProxy"> <constructor-arg> <list> <sec:filter-chain pattern="/restful/**" filters=" securityContextPersistenceFilterWithASCFalse, basicAuthenticationFilter, exceptionTranslationFilter, filterSecurityInterceptor" /> <sec:filter-chain pattern="/**" filters=" securityContextPersistenceFilterWithASCTrue, formLoginFilter, exceptionTranslationFilter, filterSecurityInterceptor" /> </list> </constructor-arg> </bean>
The namespace element filter-chain is used for convenience to set up the security filter chain(s) which are required within the application. [6]. It maps a particular URL pattern to a list of filters built up from the bean names specified in the filters element, and combines them in a bean of type SecurityFilterChain. The pattern attribute takes an Ant Paths and the most specific URIs should appear first [7]. At runtime the FilterChainProxy will locate the first URI pattern that matches the current web request and the list of filter beans specified by the filters attribute will be applied to that request. The filters will be invoked in the order they are defined, so you have complete control over the filter chain which is applied to a particular URL.
You may have noticed we have declared two SecurityContextPersistenceFilter s in the filter chain ( ASC is short for allowSessionCreation, a property of SecurityContextPersistenceFilter). As web services will never present a jsessionid on future requests, creating HttpSession s for such user agents would be wasteful. If you had a high-volume application which required maximum scalability, we recommend you use the approach shown above. For smaller applications, using a single SecurityContextPersistenceFilter (with its default allowSessionCreation as true) would likely be sufficient.
Note that FilterChainProxy does not invoke standard filter lifecycle methods on the filters it is configured with. We recommend you use Spring’s application context lifecycle interfaces as an alternative, just as you would for any other Spring bean.
When we looked at how to set up web security using namespace configuration, we used a DelegatingFilterProxy with the name "springSecurityFilterChain". You should now be able to see that this is the name of the FilterChainProxy which is created by the namespace.
You can use the attribute filters = "none" as an alternative to supplying a filter bean list. This will omit the request pattern from the security filter chain entirely. Note that anything matching this path will then have no authentication or authorization services applied and will be freely accessible. If you want to make use of the contents of the SecurityContext contents during a request, then it must have passed through the security filter chain. Otherwise the SecurityContextHolder will not have been populated and the contents will be null.
The order that filters are defined in the chain is very important. Irrespective of which filters you are actually using, the order should be as follows:
-
ChannelProcessingFilter, because it might need to redirect to a different protocol -
SecurityContextPersistenceFilter, so aSecurityContextcan be set up in theSecurityContextHolderat the beginning of a web request, and any changes to theSecurityContextcan be copied to theHttpSessionwhen the web request ends (ready for use with the next web request) -
ConcurrentSessionFilter, because it uses theSecurityContextHolderfunctionality and needs to update theSessionRegistryto reflect ongoing requests from the principal -
Authentication processing mechanisms -
UsernamePasswordAuthenticationFilter,CasAuthenticationFilter,BasicAuthenticationFilteretc - so that theSecurityContextHoldercan be modified to contain a validAuthenticationrequest token -
The
SecurityContextHolderAwareRequestFilter, if you are using it to install a Spring Security awareHttpServletRequestWrapperinto your servlet container -
The
JaasApiIntegrationFilter, if aJaasAuthenticationTokenis in theSecurityContextHolderthis will process theFilterChainas theSubjectin theJaasAuthenticationToken -
RememberMeAuthenticationFilter, so that if no earlier authentication processing mechanism updated theSecurityContextHolder, and the request presents a cookie that enables remember-me services to take place, a suitable rememberedAuthenticationobject will be put there -
AnonymousAuthenticationFilter, so that if no earlier authentication processing mechanism updated theSecurityContextHolder, an anonymousAuthenticationobject will be put there -
ExceptionTranslationFilter, to catch any Spring Security exceptions so that either an HTTP error response can be returned or an appropriateAuthenticationEntryPointcan be launched -
FilterSecurityInterceptor, to protect web URIs and raise exceptions when access is denied
Spring Security has several areas where patterns you have defined are tested against incoming requests in order to decide how the request should be handled. This occurs when the FilterChainProxy decides which filter chain a request should be passed through and also when the FilterSecurityInterceptor decides which security constraints apply to a request. It’s important to understand what the mechanism is and what URL value is used when testing against the patterns that you define.
The Servlet Specification defines several properties for the HttpServletRequest which are accessible via getter methods, and which we might want to match against. These are the contextPath, servletPath, pathInfo and queryString. Spring Security is only interested in securing paths within the application, so the contextPath is ignored. Unfortunately, the servlet spec does not define exactly what the values of servletPath and pathInfo will contain for a particular request URI. For example, each path segment of a URL may contain parameters, as defined in RFC 2396 [8]. The Specification does not clearly state whether these should be included in the servletPath and pathInfo values and the behaviour varies between different servlet containers. There is a danger that when an application is deployed in a container which does not strip path parameters from these values, an attacker could add them to the requested URL in order to cause a pattern match to succeed or fail unexpectedly. [9]. Other variations in the incoming URL are also possible. For example, it could contain path-traversal sequences (like /../) or multiple forward slashes (//) which could also cause pattern-matches to fail. Some containers normalize these out before performing the servlet mapping, but others don’t. To protect against issues like these, FilterChainProxy uses an HttpFirewall strategy to check and wrap the request. Un-normalized requests are automatically rejected by default, and path parameters and duplicate slashes are removed for matching purposes. [10]. It is therefore essential that a FilterChainProxy is used to manage the security filter chain. Note that the servletPath and pathInfo values are decoded by the container, so your application should not have any valid paths which contain semi-colons, as these parts will be removed for matching purposes.
As mentioned above, the default strategy is to use Ant-style paths for matching and this is likely to be the best choice for most users. The strategy is implemented in the class AntPathRequestMatcher which uses Spring’s AntPathMatcher to perform a case-insensitive match of the pattern against the concatenated servletPath and pathInfo, ignoring the queryString.
If for some reason, you need a more powerful matching strategy, you can use regular expressions. The strategy implementation is then RegexRequestMatcher. See the Javadoc for this class for more information.
In practice we recommend that you use method security at your service layer, to control access to your application, and do not rely entirely on the use of security constraints defined at the web-application level. URLs change and it is difficult to take account of all the possible URLs that an application might support and how requests might be manipulated. You should try and restrict yourself to using a few simple ant paths which are simple to understand. Always try to use a"deny-by-default" approach where you have a catch-all wildcard ( / or ) defined last and denying access.
Security defined at the service layer is much more robust and harder to bypass, so you should always take advantage of Spring Security’s method security options.
If you’re using some other framework that is also filter-based, then you need to make sure that the Spring Security filters come first. This enables the SecurityContextHolder to be populated in time for use by the other filters. Examples are the use of SiteMesh to decorate your web pages or a web framework like Wicket which uses a filter to handle its requests.
As we saw earlier in the namespace chapter, it’s possible to use multiple http elements to define different security configurations for different URL patterns. Each element creates a filter chain within the internal FilterChainProxy and the URL pattern that should be mapped to it. The elements will be added in the order they are declared, so the most specific patterns must again be declared first. Here’s another example, for a similar situation to that above, where the application supports both a stateless RESTful API and also a normal web application which users log into using a form.
<!-- Stateless RESTful service using Basic authentication --> <http pattern="/restful/**" create-session="stateless"> <intercept-url pattern='/**' access="hasRole('REMOTE')" /> <http-basic /> </http> <!-- Empty filter chain for the login page --> <http pattern="/login.htm*" security="none"/> <!-- Additional filter chain for normal users, matching all other requests --> <http> <intercept-url pattern='/**' access="hasRole('USER')" /> <form-login login-page='/login.htm' default-target-url="/home.htm"/> <logout /> </http>
[6] Note that you’ll need to include the security namespace in your application context XML file in order to use this syntax. The older syntax which used a filter-chain-map is still supported, but is deprecated in favour of the constructor argument injection.
[7] Instead of a path pattern, the request-matcher-ref attribute can be used to specify a RequestMatcher instance for more powerful matching
[8] You have probably seen this when a browser doesn’t support cookies and the jsessionid parameter is appended to the URL after a semi-colon. However the RFC allows the presence of these parameters in any path segment of the URL
[9] The original values will be returned once the request leaves the FilterChainProxy, so will still be available to the application.
[10] So, for example, an original request path /secure;hack=1/somefile.html;hack=2 will be returned as /secure/somefile.html.
There are some key filters which will always be used in a web application which uses Spring Security, so we’ll look at these and their supporting classes and interfaces first. We won’t cover every feature, so be sure to look at the Javadoc for them if you want to get the complete picture.
We’ve already seen FilterSecurityInterceptor briefly when discussing access-control in general, and we’ve already used it with the namespace where the <intercept-url> elements are combined to configure it internally. Now we’ll see how to explicitly configure it for use with a FilterChainProxy, along with its companion filter ExceptionTranslationFilter. A typical configuration example is shown below:
<bean id="filterSecurityInterceptor" class="org.springframework.security.web.access.intercept.FilterSecurityInterceptor"> <property name="authenticationManager" ref="authenticationManager"/> <property name="accessDecisionManager" ref="accessDecisionManager"/> <property name="securityMetadataSource"> <security:filter-security-metadata-source> <security:intercept-url pattern="/secure/super/**" access="ROLE_WE_DONT_HAVE"/> <security:intercept-url pattern="/secure/**" access="ROLE_SUPERVISOR,ROLE_TELLER"/> </security:filter-security-metadata-source> </property> </bean>
FilterSecurityInterceptor is responsible for handling the security of HTTP resources. It requires a reference to an AuthenticationManager and an AccessDecisionManager. It is also supplied with configuration attributes that apply to different HTTP URL requests. Refer back to the original discussion on these in the technical introduction.
The FilterSecurityInterceptor can be configured with configuration attributes in two ways. The first, which is shown above, is using the <filter-security-metadata-source> namespace element. This is similar to the <http> element from the namespace chapter but the <intercept-url> child elements only use the pattern and access attributes. Commas are used to delimit the different configuration attributes that apply to each HTTP URL. The second option is to write your own SecurityMetadataSource, but this is beyond the scope of this document. Irrespective of the approach used, the SecurityMetadataSource is responsible for returning a List<ConfigAttribute> containing all of the configuration attributes associated with a single secure HTTP URL.
It should be noted that the FilterSecurityInterceptor.setSecurityMetadataSource() method actually expects an instance of FilterInvocationSecurityMetadataSource. This is a marker interface which subclasses SecurityMetadataSource. It simply denotes the SecurityMetadataSource understands FilterInvocation s. In the interests of simplicity we’ll continue to refer to the FilterInvocationSecurityMetadataSource as a SecurityMetadataSource, as the distinction is of little relevance to most users.
The SecurityMetadataSource created by the namespace syntax obtains the configuration attributes for a particular FilterInvocation by matching the request URL against the configured pattern attributes. This behaves in the same way as it does for namespace configuration. The default is to treat all expressions as Apache Ant paths and regular expressions are also supported for more complex cases. The request-matcher attribute is used to specify the type of pattern being used. It is not possible to mix expression syntaxes within the same definition. As an example, the previous configuration using regular expressions instead of Ant paths would be written as follows:
<bean id="filterInvocationInterceptor" class="org.springframework.security.web.access.intercept.FilterSecurityInterceptor"> <property name="authenticationManager" ref="authenticationManager"/> <property name="accessDecisionManager" ref="accessDecisionManager"/> <property name="runAsManager" ref="runAsManager"/> <property name="securityMetadataSource"> <security:filter-security-metadata-source request-matcher="regex"> <security:intercept-url pattern="\A/secure/super/.*\Z" access="ROLE_WE_DONT_HAVE"/> <security:intercept-url pattern="\A/secure/.*\" access="ROLE_SUPERVISOR,ROLE_TELLER"/> </security:filter-security-metadata-source> </property> </bean>
Patterns are always evaluated in the order they are defined. Thus it is important that more specific patterns are defined higher in the list than less specific patterns. This is reflected in our example above, where the more specific /secure/super/ pattern appears higher than the less specific /secure/ pattern. If they were reversed, the /secure/ pattern would always match and the /secure/super/ pattern would never be evaluated.
The ExceptionTranslationFilter sits above the FilterSecurityInterceptor in the security filter stack. It doesn’t do any actual security enforcement itself, but handles exceptions thrown by the security interceptors and provides suitable and HTTP responses.
<bean id="exceptionTranslationFilter" class="org.springframework.security.web.access.ExceptionTranslationFilter"> <property name="authenticationEntryPoint" ref="authenticationEntryPoint"/> <property name="accessDeniedHandler" ref="accessDeniedHandler"/> </bean> <bean id="authenticationEntryPoint" class="org.springframework.security.web.authentication.LoginUrlAuthenticationEntryPoint"> <property name="loginFormUrl" value="/login.jsp"/> </bean> <bean id="accessDeniedHandler" class="org.springframework.security.web.access.AccessDeniedHandlerImpl"> <property name="errorPage" value="/accessDenied.htm"/> </bean>
The AuthenticationEntryPoint will be called if the user requests a secure HTTP resource but they are not authenticated. An appropriate AuthenticationException or AccessDeniedException will be thrown by a security interceptor further down the call stack, triggering the commence method on the entry point. This does the job of presenting the appropriate response to the user so that authentication can begin. The one we’ve used here is LoginUrlAuthenticationEntryPoint, which redirects the request to a different URL (typically a login page). The actual implementation used will depend on the authentication mechanism you want to be used in your application.
What happens if a user is already authenticated and they try to access a protected resource? In normal usage, this shouldn’t happen because the application workflow should be restricted to operations to which a user has access. For example, an HTML link to an administration page might be hidden from users who do not have an admin role. You can’t rely on hiding links for security though, as there’s always a possibility that a user will just enter the URL directly in an attempt to bypass the restrictions. Or they might modify a RESTful URL to change some of the argument values. Your application must be protected against these scenarios or it will definitely be insecure. You will typically use simple web layer security to apply constraints to basic URLs and use more specific method-based security on your service layer interfaces to really nail down what is permissible.
If an AccessDeniedException is thrown and a user has already been authenticated, then this means that an operation has been attempted for which they don’t have enough permissions. In this case, ExceptionTranslationFilter will invoke a second strategy, the AccessDeniedHandler. By default, an AccessDeniedHandlerImpl is used, which just sends a 403 (Forbidden) response to the client. Alternatively you can configure an instance explicitly (as in the above example) and set an error page URL which it will forwards the request to [11]. This can be a simple "access denied" page, such as a JSP, or it could be a more complex handler such as an MVC controller. And of course, you can implement the interface yourself and use your own implementation.
It’s also possible to supply a custom AccessDeniedHandler when you’re using the namespace to configure your application. See the namespace appendix for more details.
Another responsibility of ExceptionTranslationFilter responsibilities is to save the current request before invoking the AuthenticationEntryPoint. This allows the request to be restored after the use has authenticated (see previous overview of web authentication). A typical example would be where the user logs in with a form, and is then redirected to the original URL by the default SavedRequestAwareAuthenticationSuccessHandler (see below).
The RequestCache encapsulates the functionality required for storing and retrieving HttpServletRequest instances. By default the HttpSessionRequestCache is used, which stores the request in the HttpSession. The RequestCacheFilter has the job of actually restoring the saved request from the cache when the user is redirected to the original URL.
Under normal circumstances, you shouldn’t need to modify any of this functionality, but the saved-request handling is a "best-effort" approach and there may be situations which the default configuration isn’t able to handle. The use of these interfaces makes it fully pluggable from Spring Security 3.0 onwards.
We covered the purpose of this all-important filter in the Technical Overview chapter so you might want to re-read that section at this point. Let’s first take a look at how you would configure it for use with a FilterChainProxy. A basic configuration only requires the bean itself
<bean id="securityContextPersistenceFilter" class="org.springframework.security.web.context.SecurityContextPersistenceFilter"/>
As we saw previously, this filter has two main tasks. It is responsible for storage of the SecurityContext contents between HTTP requests and for clearing the SecurityContextHolder when a request is completed. Clearing the ThreadLocal in which the context is stored is essential, as it might otherwise be possible for a thread to be replaced into the servlet container’s thread pool, with the security context for a particular user still attached. This thread might then be used at a later stage, performing operations with the wrong credentials.
From Spring Security 3.0, the job of loading and storing the security context is now delegated to a separate strategy interface:
public interface SecurityContextRepository { SecurityContext loadContext(HttpRequestResponseHolder requestResponseHolder); void saveContext(SecurityContext context, HttpServletRequest request, HttpServletResponse response); }
The HttpRequestResponseHolder is simply a container for the incoming request and response objects, allowing the implementation to replace these with wrapper classes. The returned contents will be passed to the filter chain.
The default implementation is HttpSessionSecurityContextRepository, which stores the security context as an HttpSession attribute [12]. The most important configuration parameter for this implementation is the allowSessionCreation property, which defaults to true, thus allowing the class to create a session if it needs one to store the security context for an authenticated user (it won’t create one unless authentication has taken place and the contents of the security context have changed). If you don’t want a session to be created, then you can set this property to false:
<bean id="securityContextPersistenceFilter" class="org.springframework.security.web.context.SecurityContextPersistenceFilter"> <property name='securityContextRepository'> <bean class='org.springframework.security.web.context.HttpSessionSecurityContextRepository'> <property name='allowSessionCreation' value='false' /> </bean> </property> </bean>
Alternatively you could provide an instance of NullSecurityContextRepository, a null object implementation, which will prevent the security context from being stored, even if a session has already been created during the request.
We’ve now seen the three main filters which are always present in a Spring Security web configuration. These are also the three which are automatically created by the namespace <http> element and cannot be substituted with alternatives. The only thing that’s missing now is an actual authentication mechanism, something that will allow a user to authenticate. This filter is the most commonly used authentication filter and the one that is most often customized [13]. It also provides the implementation used by the <form-login> element from the namespace. There are three stages required to configure it.
-
Configure a
LoginUrlAuthenticationEntryPointwith the URL of the login page, just as we did above, and set it on theExceptionTranslationFilter. - Implement the login page (using a JSP or MVC controller).
-
Configure an instance of
UsernamePasswordAuthenticationFilterin the application context - Add the filter bean to your filter chain proxy (making sure you pay attention to the order).
The login form simply contains username and password input fields, and posts to the URL that is monitored by the filter (by default this is /login). The basic filter configuration looks something like this:
<bean id="authenticationFilter" class= "org.springframework.security.web.authentication.UsernamePasswordAuthenticationFilter"> <property name="authenticationManager" ref="authenticationManager"/> </bean>
The filter calls the configured AuthenticationManager to process each authentication request. The destination following a successful authentication or an authentication failure is controlled by the AuthenticationSuccessHandler and AuthenticationFailureHandler strategy interfaces, respectively. The filter has properties which allow you to set these so you can customize the behaviour completely [14]. Some standard implementations are supplied such as SimpleUrlAuthenticationSuccessHandler, SavedRequestAwareAuthenticationSuccessHandler, SimpleUrlAuthenticationFailureHandler and ExceptionMappingAuthenticationFailureHandler. Have a look at the Javadoc for these classes and also for AbstractAuthenticationProcessingFilter to get an overview of how they work and the supported features.
If authentication is successful, the resulting Authentication object will be placed into the SecurityContextHolder. The configured AuthenticationSuccessHandler will then be called to either redirect or forward the user to the appropriate destination. By default a SavedRequestAwareAuthenticationSuccessHandler is used, which means that the user will be redirected to the original destination they requested before they were asked to login.
| Note |
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The |
If authentication fails, the configured AuthenticationFailureHandler will be invoked.
[11] We use a forward so that the SecurityContextHolder still contains details of the principal, which may be useful for displaying to the user. In old releases of Spring Security we relied upon the servlet container to handle a 403 error message, which lacked this useful contextual information.
[12] In Spring Security 2.0 and earlier, this filter was called HttpSessionContextIntegrationFilter and performed all the work of storing the context was performed by the filter itself. If you were familiar with this class, then most of the configuration options which were available can now be found on HttpSessionSecurityContextRepository.
[13] For historical reasons, prior to Spring Security 3.0, this filter was called AuthenticationProcessingFilter and the entry point was called AuthenticationProcessingFilterEntryPoint. Since the framework now supports many different forms of authentication, they have both been given more specific names in 3.0.
[14] In versions prior to 3.0, the application flow at this point had evolved to a stage was controlled by a mix of properties on this class and strategy plugins. The decision was made for 3.0 to refactor the code to make these two strategies entirely responsible.
This section describes how Spring Security is integrated with the Servlet API. The servletapi-xml sample application demonstrates the usage of each of these methods.
The HttpServletRequest.getRemoteUser() will return the result of SecurityContextHolder.getContext().getAuthentication().getName() which is typically the current username. This can be useful if you want to display the current username in your application. Additionally, checking if this is null can be used to indicate if a user has authenticated or is anonymous. Knowing if the user is authenticated or not can be useful for determining if certain UI elements should be shown or not (i.e. a log out link should only be displayed if the user is authenticated).
The HttpServletRequest.getUserPrincipal() will return the result of SecurityContextHolder.getContext().getAuthentication(). This means it is an Authentication which is typically an instance of UsernamePasswordAuthenticationToken when using username and password based authentication. This can be useful if you need additional information about your user. For example, you might have created a custom UserDetailsService that returns a custom UserDetails containing a first and last name for your user. You could obtain this information with the following:
Authentication auth = httpServletRequest.getUserPrincipal(); // assume integrated custom UserDetails called MyCustomUserDetails // by default, typically instance of UserDetails MyCustomUserDetails userDetails = (MyCustomUserDetails) auth.getPrincipal(); String firstName = userDetails.getFirstName(); String lastName = userDetails.getLastName();
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It should be noted that it is typically bad practice to perform so much logic throughout your application. Instead, one should centralize it to reduce any coupling of Spring Security and the Servlet API’s. |
The HttpServletRequest.isUserInRole(String) will determine if SecurityContextHolder.getContext().getAuthentication().getAuthorities() contains a GrantedAuthority with the role passed into isUserInRole(String). Typically users should not pass in the "ROLE_" prefix into this method since it is added automatically. For example, if you want to determine if the current user has the authority "ROLE_ADMIN", you could use the following:
boolean isAdmin = httpServletRequest.isUserInRole("ADMIN");
This might be useful to determine if certain UI components should be displayed. For example, you might display admin links only if the current user is an admin.
The following section describes the Servlet 3 methods that Spring Security integrates with.
The HttpServletRequest.authenticate(HttpServletRequest,HttpServletResponse) method can be used to ensure that a user is authenticated. If they are not authenticated, the configured AuthenticationEntryPoint will be used to request the user to authenticate (i.e. redirect to the login page).
The HttpServletRequest.login(String,String) method can be used to authenticate the user with the current AuthenticationManager. For example, the following would attempt to authenticate with the username "user" and password "password":
try { httpServletRequest.login("user","password"); } catch(ServletException e) { // fail to authenticate }
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It is not necessary to catch the ServletException if you want Spring Security to process the failed authentication attempt. |
The HttpServletRequest.logout() method can be used to log the current user out.
Typically this means that the SecurityContextHolder will be cleared out, the HttpSession will be invalidated, any "Remember Me" authentication will be cleaned up, etc. However, the configured LogoutHandler implementations will vary depending on your Spring Security configuration. It is important to note that after HttpServletRequest.logout() has been invoked, you are still in charge of writing a response out. Typically this would involve a redirect to the welcome page.
The AsynchContext.start(Runnable) method that ensures your credentials will be propagated to the new Thread. Using Spring Security’s concurrency support, Spring Security overrides the AsyncContext.start(Runnable) to ensure that the current SecurityContext is used when processing the Runnable. For example, the following would output the current user’s Authentication:
final AsyncContext async = httpServletRequest.startAsync(); async.start(new Runnable() { public void run() { Authentication authentication = SecurityContextHolder.getContext().getAuthentication(); try { final HttpServletResponse asyncResponse = (HttpServletResponse) async.getResponse(); asyncResponse.setStatus(HttpServletResponse.SC_OK); asyncResponse.getWriter().write(String.valueOf(authentication)); async.complete(); } catch(Exception e) { throw new RuntimeException(e); } } });
If you are using Java Based configuration, you are ready to go. If you are using XML configuration, there are a few updates that are necessary. The first step is to ensure you have updated your web.xml to use at least the 3.0 schema as shown below:
<web-app xmlns="http://java.sun.com/xml/ns/javaee" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_3_0.xsd" version="3.0"> </web-app>
Next you need to ensure that your springSecurityFilterChain is setup for processing asynchronous requests.
<filter> <filter-name>springSecurityFilterChain</filter-name> <filter-class> org.springframework.web.filter.DelegatingFilterProxy </filter-class> <async-supported>true</async-supported> </filter> <filter-mapping> <filter-name>springSecurityFilterChain</filter-name> <url-pattern>/*</url-pattern> <dispatcher>REQUEST</dispatcher> <dispatcher>ASYNC</dispatcher> </filter-mapping>
That’s it! Now Spring Security will ensure that your SecurityContext is propagated on asynchronous requests too.
So how does it work? If you are not really interested, feel free to skip the remainder of this section, otherwise read on. Most of this is built into the Servlet specification, but there is a little bit of tweaking that Spring Security does to ensure things work with asynchronous requests properly. Prior to Spring Security 3.2, the SecurityContext from the SecurityContextHolder was automatically saved as soon as the HttpServletResponse was committed. This can cause issues in a Async environment. For example, consider the following:
httpServletRequest.startAsync(); new Thread("AsyncThread") { @Override public void run() { try { // Do work TimeUnit.SECONDS.sleep(1); // Write to and commit the httpServletResponse httpServletResponse.getOutputStream().flush(); } catch (Exception e) { e.printStackTrace(); } } }.start();
The issue is that this Thread is not known to Spring Security, so the SecurityContext is not propagated to it. This means when we commit the HttpServletResponse there is no SecuriytContext. When Spring Security automatically saved the SecurityContext on committing the HttpServletResponse it would lose our logged in user.
Since version 3.2, Spring Security is smart enough to no longer automatically save the SecurityContext on commiting the HttpServletResponse as soon as HttpServletRequest.startAsync() is invoked.
The following section describes the Servlet 3.1 methods that Spring Security integrates with.
The HttpServletRequest.changeSessionId() is the default method for protecting against Session Fixation attacks in Servlet 3.1 and higher.
Basic and digest authentiation are alternative authentication mechanisms which are popular in web applications. Basic authentication is often used with stateless clients which pass their credentials on each request. It’s quite common to use it in combination with form-based authentication where an application is used through both a browser-based user interface and as a web-service. However, basic authentication transmits the password as plain text so it should only really be used over an encrypted transport layer such as HTTPS.
BasicAuthenticationFilter is responsible for processing basic authentication credentials presented in HTTP headers. This can be used for authenticating calls made by Spring remoting protocols (such as Hessian and Burlap), as well as normal browser user agents (such as Firefox and Internet Explorer). The standard governing HTTP Basic Authentication is defined by RFC 1945, Section 11, and BasicAuthenticationFilter conforms with this RFC. Basic Authentication is an attractive approach to authentication, because it is very widely deployed in user agents and implementation is extremely simple (it’s just a Base64 encoding of the username:password, specified in an HTTP header).
To implement HTTP Basic Authentication, you need to add a BasicAuthenticationFilter to your filter chain. The application context should contain BasicAuthenticationFilter and its required collaborator:
<bean id="basicAuthenticationFilter" class="org.springframework.security.web.authentication.www.BasicAuthenticationFilter"> <property name="authenticationManager" ref="authenticationManager"/> <property name="authenticationEntryPoint" ref="authenticationEntryPoint"/> </bean> <bean id="authenticationEntryPoint" class="org.springframework.security.web.authentication.www.BasicAuthenticationEntryPoint"> <property name="realmName" value="Name Of Your Realm"/> </bean>
The configured AuthenticationManager processes each authentication request. If authentication fails, the configured AuthenticationEntryPoint will be used to retry the authentication process. Usually you will use the filter in combination with a BasicAuthenticationEntryPoint, which returns a 401 response with a suitable header to retry HTTP Basic authentication. If authentication is successful, the resulting Authentication object will be placed into the SecurityContextHolder as usual.
If the authentication event was successful, or authentication was not attempted because the HTTP header did not contain a supported authentication request, the filter chain will continue as normal. The only time the filter chain will be interrupted is if authentication fails and the AuthenticationEntryPoint is called.
DigestAuthenticationFilter is capable of processing digest authentication credentials presented in HTTP headers. Digest Authentication attempts to solve many of the weaknesses of Basic authentication, specifically by ensuring credentials are never sent in clear text across the wire. Many user agents support Digest Authentication, including FireFox and Internet Explorer. The standard governing HTTP Digest Authentication is defined by RFC 2617, which updates an earlier version of the Digest Authentication standard prescribed by RFC 2069. Most user agents implement RFC 2617. Spring Security’s DigestAuthenticationFilter is compatible with the “auth” quality of protection (qop) prescribed by RFC 2617, which also provides backward compatibility with RFC 2069. Digest Authentication is a more attractive option if you need to use unencrypted HTTP (i.e. no TLS/HTTPS) and wish to maximise security of the authentication process. Indeed Digest Authentication is a mandatory requirement for the WebDAV protocol, as noted by RFC 2518 Section 17.1.
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You should not use Digest in modern applications because it is not considered secure. The most obvious problem is that you must store your passwords in plaintext, encrpted, or an MD5 format. All of these storage formats are considered insecure. Instead, you should use a one way adaptive password hash (i.e. BCrypt, PBKDF2, SCrypt, etc). |
Central to Digest Authentication is a "nonce". This is a value the server generates. Spring Security’s nonce adopts the following format:
base64(expirationTime + ":" + md5Hex(expirationTime + ":" + key)) expirationTime: The date and time when the nonce expires, expressed in milliseconds key: A private key to prevent modification of the nonce token
The DigestAuthenticatonEntryPoint has a property specifying the key used for generating the nonce tokens, along with a nonceValiditySeconds property for determining the expiration time (default 300, which equals five minutes). Whist ever the nonce is valid, the digest is computed by concatenating various strings including the username, password, nonce, URI being requested, a client-generated nonce (merely a random value which the user agent generates each request), the realm name etc, then performing an MD5 hash. Both the server and user agent perform this digest computation, resulting in different hash codes if they disagree on an included value (eg password). In Spring Security implementation, if the server-generated nonce has merely expired (but the digest was otherwise valid), the DigestAuthenticationEntryPoint will send a "stale=true" header. This tells the user agent there is no need to disturb the user (as the password and username etc is correct), but simply to try again using a new nonce.
An appropriate value for the nonceValiditySeconds parameter of DigestAuthenticationEntryPoint depends on your application. Extremely secure applications should note that an intercepted authentication header can be used to impersonate the principal until the expirationTime contained in the nonce is reached. This is the key principle when selecting an appropriate setting, but it would be unusual for immensely secure applications to not be running over TLS/HTTPS in the first instance.
Because of the more complex implementation of Digest Authentication, there are often user agent issues. For example, Internet Explorer fails to present an “opaque” token on subsequent requests in the same session. Spring Security filters therefore encapsulate all state information into the “nonce” token instead. In our testing, Spring Security’s implementation works reliably with FireFox and Internet Explorer, correctly handling nonce timeouts etc.
Now that we’ve reviewed the theory, let’s see how to use it. To implement HTTP Digest Authentication, it is necessary to define DigestAuthenticationFilter in the filter chain. The application context will need to define the DigestAuthenticationFilter and its required collaborators:
<bean id="digestFilter" class= "org.springframework.security.web.authentication.www.DigestAuthenticationFilter"> <property name="userDetailsService" ref="jdbcDaoImpl"/> <property name="authenticationEntryPoint" ref="digestEntryPoint"/> <property name="userCache" ref="userCache"/> </bean> <bean id="digestEntryPoint" class= "org.springframework.security.web.authentication.www.DigestAuthenticationEntryPoint"> <property name="realmName" value="Contacts Realm via Digest Authentication"/> <property name="key" value="acegi"/> <property name="nonceValiditySeconds" value="10"/> </bean>
The configured UserDetailsService is needed because DigestAuthenticationFilter must have direct access to the clear text password of a user. Digest Authentication will NOT work if you are using encoded passwords in your DAO [15]. The DAO collaborator, along with the UserCache, are typically shared directly with a DaoAuthenticationProvider. The authenticationEntryPoint property must be DigestAuthenticationEntryPoint, so that DigestAuthenticationFilter can obtain the correct realmName and key for digest calculations.
Like BasicAuthenticationFilter, if authentication is successful an Authentication request token will be placed into the SecurityContextHolder. If the authentication event was successful, or authentication was not attempted because the HTTP header did not contain a Digest Authentication request, the filter chain will continue as normal. The only time the filter chain will be interrupted is if authentication fails and the AuthenticationEntryPoint is called, as discussed in the previous paragraph.
Digest Authentication’s RFC offers a range of additional features to further increase security. For example, the nonce can be changed on every request. Despite this, Spring Security implementation was designed to minimise the complexity of the implementation (and the doubtless user agent incompatibilities that would emerge), and avoid needing to store server-side state. You are invited to review RFC 2617 if you wish to explore these features in more detail. As far as we are aware, Spring Security’s implementation does comply with the minimum standards of this RFC.
[15] It is possible to encode the password in the format HEX( MD5(username:realm:password) ) provided the DigestAuthenticationFilter.passwordAlreadyEncoded is set to true. However, other password encodings will not work with digest authentication.
Remember-me or persistent-login authentication refers to web sites being able to remember the identity of a principal between sessions. This is typically accomplished by sending a cookie to the browser, with the cookie being detected during future sessions and causing automated login to take place. Spring Security provides the necessary hooks for these operations to take place, and has two concrete remember-me implementations. One uses hashing to preserve the security of cookie-based tokens and the other uses a database or other persistent storage mechanism to store the generated tokens.
Note that both implemementations require a UserDetailsService. If you are using an authentication provider which doesn’t use a UserDetailsService (for example, the LDAP provider) then it won’t work unless you also have a UserDetailsService bean in your application context.
This approach uses hashing to achieve a useful remember-me strategy. In essence a cookie is sent to the browser upon successful interactive authentication, with the cookie being composed as follows:
base64(username + ":" + expirationTime + ":" + md5Hex(username + ":" + expirationTime + ":" password + ":" + key)) username: As identifiable to the UserDetailsService password: That matches the one in the retrieved UserDetails expirationTime: The date and time when the remember-me token expires, expressed in milliseconds key: A private key to prevent modification of the remember-me token
As such the remember-me token is valid only for the period specified, and provided that the username, password and key does not change. Notably, this has a potential security issue in that a captured remember-me token will be usable from any user agent until such time as the token expires. This is the same issue as with digest authentication. If a principal is aware a token has been captured, they can easily change their password and immediately invalidate all remember-me tokens on issue. If more significant security is needed you should use the approach described in the next section. Alternatively remember-me services should simply not be used at all.
If you are familiar with the topics discussed in the chapter on namespace configuration, you can enable remember-me authentication just by adding the <remember-me> element:
<http> ... <remember-me key="myAppKey"/> </http>
The UserDetailsService will normally be selected automatically. If you have more than one in your application context, you need to specify which one should be used with the user-service-ref attribute, where the value is the name of your UserDetailsService bean.
This approach is based on the article http://jaspan.com/improved_persistent_login_cookie_best_practice with some minor modifications [16]. To use the this approach with namespace configuration, you would supply a datasource reference:
<http> ... <remember-me data-source-ref="someDataSource"/> </http>
The database should contain a persistent_logins table, created using the following SQL (or equivalent):
create table persistent_logins (username varchar(64) not null, series varchar(64) primary key, token varchar(64) not null, last_used timestamp not null)
Remember-me is used with UsernamePasswordAuthenticationFilter, and is implemented via hooks in the AbstractAuthenticationProcessingFilter superclass.
It is also used within BasicAuthenticationFilter.
The hooks will invoke a concrete RememberMeServices at the appropriate times.
The interface looks like this:
Authentication autoLogin(HttpServletRequest request, HttpServletResponse response); void loginFail(HttpServletRequest request, HttpServletResponse response); void loginSuccess(HttpServletRequest request, HttpServletResponse response, Authentication successfulAuthentication);
Please refer to the JavaDocs for a fuller discussion on what the methods do, although note at this stage that AbstractAuthenticationProcessingFilter only calls the loginFail() and loginSuccess() methods. The autoLogin() method is called by RememberMeAuthenticationFilter whenever the SecurityContextHolder does not contain an Authentication. This interface therefore provides the underlying remember-me implementation with sufficient notification of authentication-related events, and delegates to the implementation whenever a candidate web request might contain a cookie and wish to be remembered. This design allows any number of remember-me implementation strategies. We’ve seen above that Spring Security provides two implementations. We’ll look at these in turn.
This implementation supports the simpler approach described in Section 17.2, “Simple Hash-Based Token Approach”. TokenBasedRememberMeServices generates a RememberMeAuthenticationToken, which is processed by RememberMeAuthenticationProvider. A key is shared between this authentication provider and the TokenBasedRememberMeServices. In addition, TokenBasedRememberMeServices requires A UserDetailsService from which it can retrieve the username and password for signature comparison purposes, and generate the RememberMeAuthenticationToken to contain the correct GrantedAuthority s. Some sort of logout command should be provided by the application that invalidates the cookie if the user requests this. TokenBasedRememberMeServices also implements Spring Security’s LogoutHandler interface so can be used with LogoutFilter to have the cookie cleared automatically.
The beans required in an application context to enable remember-me services are as follows:
<bean id="rememberMeFilter" class= "org.springframework.security.web.authentication.rememberme.RememberMeAuthenticationFilter"> <property name="rememberMeServices" ref="rememberMeServices"/> <property name="authenticationManager" ref="theAuthenticationManager" /> </bean> <bean id="rememberMeServices" class= "org.springframework.security.web.authentication.rememberme.TokenBasedRememberMeServices"> <property name="userDetailsService" ref="myUserDetailsService"/> <property name="key" value="springRocks"/> </bean> <bean id="rememberMeAuthenticationProvider" class= "org.springframework.security.authentication.RememberMeAuthenticationProvider"> <property name="key" value="springRocks"/> </bean>
Don’t forget to add your RememberMeServices implementation to your UsernamePasswordAuthenticationFilter.setRememberMeServices() property, include the RememberMeAuthenticationProvider in your AuthenticationManager.setProviders() list, and add RememberMeAuthenticationFilter into your FilterChainProxy (typically immediately after your UsernamePasswordAuthenticationFilter).
This class can be used in the same way as TokenBasedRememberMeServices, but it additionally needs to be configured with a PersistentTokenRepository to store the tokens. There are two standard implementations.
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InMemoryTokenRepositoryImplwhich is intended for testing only. -
JdbcTokenRepositoryImplwhich stores the tokens in a database.
The database schema is described above in Section 17.3, “Persistent Token Approach”.
[16] Essentially, the username is not included in the cookie, to prevent exposing a valid login name unecessarily. There is a discussion on this in the comments section of this article.
This section discusses Spring Security’s Cross Site Request Forgery (CSRF) support.
Before we discuss how Spring Security can protect applications from CSRF attacks, we will explain what a CSRF attack is. Let’s take a look at a concrete example to get a better understanding.
Assume that your bank’s website provides a form that allows transferring money from the currently logged in user to another bank account. For example, the HTTP request might look like:
POST /transfer HTTP/1.1 Host: bank.example.com Cookie: JSESSIONID=randomid; Domain=bank.example.com; Secure; HttpOnly Content-Type: application/x-www-form-urlencoded amount=100.00&routingNumber=1234&account=9876
Now pretend you authenticate to your bank’s website and then, without logging out, visit an evil website. The evil website contains an HTML page with the following form:
<form action="https://bank.example.com/transfer" method="post"> <input type="hidden" name="amount" value="100.00"/> <input type="hidden" name="routingNumber" value="evilsRoutingNumber"/> <input type="hidden" name="account" value="evilsAccountNumber"/> <input type="submit" value="Win Money!"/> </form>
You like to win money, so you click on the submit button. In the process, you have unintentionally transferred $100 to a malicious user. This happens because, while the evil website cannot see your cookies, the cookies associated with your bank are still sent along with the request.
Worst yet, this whole process could have been automated using JavaScript. This means you didn’t even need to click on the button. So how do we protect ourselves from such attacks?
The issue is that the HTTP request from the bank’s website and the request from the evil website are exactly the same. This means there is no way to reject requests coming from the evil website and allow requests coming from the bank’s website. To protect against CSRF attacks we need to ensure there is something in the request that the evil site is unable to provide.
One solution is to use the Synchronizer Token Pattern. This solution is to ensure that each request requires, in addition to our session cookie, a randomly generated token as an HTTP parameter. When a request is submitted, the server must look up the expected value for the parameter and compare it against the actual value in the request. If the values do not match, the request should fail.
We can relax the expectations to only require the token for each HTTP request that updates state. This can be safely done since the same origin policy ensures the evil site cannot read the response. Additionally, we do not want to include the random token in HTTP GET as this can cause the tokens to be leaked.
Let’s take a look at how our example would change. Assume the randomly generated token is present in an HTTP parameter named _csrf. For example, the request to transfer money would look like this:
POST /transfer HTTP/1.1 Host: bank.example.com Cookie: JSESSIONID=randomid; Domain=bank.example.com; Secure; HttpOnly Content-Type: application/x-www-form-urlencoded amount=100.00&routingNumber=1234&account=9876&_csrf=<secure-random>
You will notice that we added the _csrf parameter with a random value. Now the evil website will not be able to guess the correct value for the _csrf parameter (which must be explicitly provided on the evil website) and the transfer will fail when the server compares the actual token to the expected token.
When should you use CSRF protection? Our recommendation is to use CSRF protection for any request that could be processed by a browser by normal users. If you are only creating a service that is used by non-browser clients, you will likely want to disable CSRF protection.
A common question is "do I need to protect JSON requests made by javascript?" The short answer is, it depends. However, you must be very careful as there are CSRF exploits that can impact JSON requests. For example, a malicious user can create a CSRF with JSON using the following form:
<form action="https://bank.example.com/transfer" method="post" enctype="text/plain"> <input name='{"amount":100,"routingNumber":"evilsRoutingNumber","account":"evilsAccountNumber", "ignore_me":"' value='test"}' type='hidden'> <input type="submit" value="Win Money!"/> </form>
This will produce the following JSON structure
{ "amount": 100,
"routingNumber": "evilsRoutingNumber",
"account": "evilsAccountNumber",
"ignore_me": "=test"
}
If an application were not validating the Content-Type, then it would be exposed to this exploit. Depending on the setup, a Spring MVC application that validates the Content-Type could still be exploited by updating the URL suffix to end with ".json" as shown below:
<form action="https://bank.example.com/transfer.json" method="post" enctype="text/plain"> <input name='{"amount":100,"routingNumber":"evilsRoutingNumber","account":"evilsAccountNumber", "ignore_me":"' value='test"}' type='hidden'> <input type="submit" value="Win Money!"/> </form>
What if my application is stateless? That doesn’t necessarily mean you are protected. In fact, if a user does not need to perform any actions in the web browser for a given request, they are likely still vulnerable to CSRF attacks.
For example, consider an application uses a custom cookie that contains all the state within it for authentication instead of the JSESSIONID. When the CSRF attack is made the custom cookie will be sent with the request in the same manner that the JSESSIONID cookie was sent in our previous example.
Users using basic authentication are also vulnerable to CSRF attacks since the browser will automatically include the username password in any requests in the same manner that the JSESSIONID cookie was sent in our previous example.
So what are the steps necessary to use Spring Security’s to protect our site against CSRF attacks? The steps to using Spring Security’s CSRF protection are outlined below:
The first step to protecting against CSRF attacks is to ensure your website uses proper HTTP verbs. Specifically, before Spring Security’s CSRF support can be of use, you need to be certain that your application is using PATCH, POST, PUT, and/or DELETE for anything that modifies state.
This is not a limitation of Spring Security’s support, but instead a general requirement for proper CSRF prevention. The reason is that including private information in an HTTP GET can cause the information to be leaked. See RFC 2616 Section 15.1.3 Encoding Sensitive Information in URI’s for general guidance on using POST instead of GET for sensitive information.
The next step is to include Spring Security’s CSRF protection within your application. Some frameworks handle invalid CSRF tokens by invaliding the user’s session, but this causes its own problems. Instead by default Spring Security’s CSRF protection will produce an HTTP 403 access denied. This can be customized by configuring the AccessDeniedHandler to process InvalidCsrfTokenException differently.
As of Spring Security 4.0, CSRF protection is enabled by default with XML configuration. If you would like to disable CSRF protection, the corresponding XML configuration can be seen below.
<http> <!-- ... --> <csrf disabled="true"/> </http>
CSRF protection is enabled by default with Java Configuration. If you would like to disable CSRF, the corresponding Java configuration can be seen below. Refer to the Javadoc of csrf() for additional customizations in how CSRF protection is configured.
@EnableWebSecurity public class WebSecurityConfig extends WebSecurityConfigurerAdapter { @Override protected void configure(HttpSecurity http) throws Exception { http .csrf().disable(); } }
The last step is to ensure that you include the CSRF token in all PATCH, POST, PUT, and DELETE methods. One way to approach this is to use the _csrf request attribute to obtain the current CsrfToken. An example of doing this with a JSP is shown below:
<c:url var="logoutUrl" value="/logout"/> <form action="${logoutUrl}" method="post"> <input type="submit" value="Log out" /> <input type="hidden" name="${_csrf.parameterName}" value="${_csrf.token}"/> </form>
An easier approach is to use the csrfInput tag from the Spring Security JSP tag library.
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If you are using Spring MVC |
If you are using JSON, then it is not possible to submit the CSRF token within an HTTP parameter. Instead you can submit the token within a HTTP header. A typical pattern would be to include the CSRF token within your meta tags. An example with a JSP is shown below:
<html> <head> <meta name="_csrf" content="${_csrf.token}"/> <!-- default header name is X-CSRF-TOKEN --> <meta name="_csrf_header" content="${_csrf.headerName}"/> <!-- ... --> </head> <!-- ... -->
Instead of manually creating the meta tags, you can use the simpler csrfMetaTags tag from the Spring Security JSP tag library.
You can then include the token within all your Ajax requests. If you were using jQuery, this could be done with the following:
$(function () { var token = $("meta[name='_csrf']").attr("content"); var header = $("meta[name='_csrf_header']").attr("content"); $(document).ajaxSend(function(e, xhr, options) { xhr.setRequestHeader(header, token); }); });
As an alternative to jQuery, we recommend using cujoJS’s rest.js. The rest.js module provides advanced support for working with HTTP requests and responses in RESTful ways. A core capability is the ability to contextualize the HTTP client adding behavior as needed by chaining interceptors on to the client.
var client = rest.chain(csrf, { token: $("meta[name='_csrf']").attr("content"), name: $("meta[name='_csrf_header']").attr("content") });
The configured client can be shared with any component of the application that needs to make a request to the CSRF protected resource. One significant different between rest.js and jQuery is that only requests made with the configured client will contain the CSRF token, vs jQuery where all requests will include the token. The ability to scope which requests receive the token helps guard against leaking the CSRF token to a third party. Please refer to the rest.js reference documentation for more information on rest.js.
There can be cases where users will want to persist the CsrfToken in a cookie.
By default the CookieCsrfTokenRepository will write to a cookie named XSRF-TOKEN and read it from a header named X-XSRF-TOKEN or the HTTP parameter _csrf.
These defaults come from AngularJS
You can configure CookieCsrfTokenRepository in XML using the following:
<http> <!-- ... --> <csrf token-repository-ref="tokenRepository"/> </http> <b:bean id="tokenRepository" class="org.springframework.security.web.csrf.CookieCsrfTokenRepository" p:cookieHttpOnly="false"/>
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The sample explicitly sets |
You can configure CookieCsrfTokenRepository in Java Configuration using:
@EnableWebSecurity public class WebSecurityConfig extends WebSecurityConfigurerAdapter { @Override protected void configure(HttpSecurity http) throws Exception { http .csrf() .csrfTokenRepository(CookieCsrfTokenRepository.withHttpOnlyFalse()); } }
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The sample explicitly sets |
There are a few caveats when implementing CSRF.
One issue is that the expected CSRF token is stored in the HttpSession, so as soon as the HttpSession expires your configured AccessDeniedHandler will receive a InvalidCsrfTokenException. If you are using the default AccessDeniedHandler, the browser will get an HTTP 403 and display a poor error message.
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One might ask why the expected |
A simple way to mitigate an active user experiencing a timeout is to have some JavaScript that lets the user know their session is about to expire. The user can click a button to continue and refresh the session.
Alternatively, specifying a custom AccessDeniedHandler allows you to process the InvalidCsrfTokenException any way you like. For an example of how to customize the AccessDeniedHandler refer to the provided links for both xml and Java configuration.
Finally, the application can be configured to use CookieCsrfTokenRepository which will not expire. As previously mentioned, this is not as secure as using a session, but in many cases can be good enough.
In order to protect against forging log in requests the log in form should be protected against CSRF attacks too. Since the CsrfToken is stored in HttpSession, this means an HttpSession will be created as soon as CsrfToken token attribute is accessed. While this sounds bad in a RESTful / stateless architecture the reality is that state is necessary to implement practical security. Without state, we have nothing we can do if a token is compromised. Practically speaking, the CSRF token is quite small in size and should have a negligible impact on our architecture.
A common technique to protect the log in form is by using a javascript function to obtain a valid CSRF token before the form submission. By doing this, there is no need to think about session timeouts (discussed in the previous section) because the session is created right before the form submission (assuming that CookieCsrfTokenRepository isn’t configured instead), so the user can stay on the login page and submit the username/password when he wants. In order to achieve this, you can take advantadge of the CsrfTokenArgumentResolver provided by Spring Security and expose an endpoint like it’s described on here.
Adding CSRF will update the LogoutFilter to only use HTTP POST. This ensures that log out requires a CSRF token and that a malicious user cannot forcibly log out your users.
One approach is to use a form for log out. If you really want a link, you can use JavaScript to have the link perform a POST (i.e. maybe on a hidden form). For browsers with JavaScript that is disabled, you can optionally have the link take the user to a log out confirmation page that will perform the POST.
If you really want to use HTTP GET with logout you can do so, but remember this is generally not recommended. For example, the following Java Configuration will perform logout with the URL /logout is requested with any HTTP method:
@EnableWebSecurity public class WebSecurityConfig extends WebSecurityConfigurerAdapter { @Override protected void configure(HttpSecurity http) throws Exception { http .logout() .logoutRequestMatcher(new AntPathRequestMatcher("/logout")); } }
There are two options to using CSRF protection with multipart/form-data. Each option has its tradeoffs.
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Before you integrate Spring Security’s CSRF protection with multipart file upload, ensure that you can upload without the CSRF protection first. More information about using multipart forms with Spring can be found within the 17.10 Spring’s multipart (file upload) support section of the Spring reference and the MultipartFilter javadoc. |
The first option is to ensure that the MultipartFilter is specified before the Spring Security filter. Specifying the MultipartFilter before the Spring Security filter means that there is no authorization for invoking the MultipartFilter which means anyone can place temporary files on your server. However, only authorized users will be able to submit a File that is processed by your application. In general, this is the recommended approach because the temporary file upload should have a negligble impact on most servers.
To ensure MultipartFilter is specified before the Spring Security filter with java configuration, users can override beforeSpringSecurityFilterChain as shown below:
public class SecurityApplicationInitializer extends AbstractSecurityWebApplicationInitializer { @Override protected void beforeSpringSecurityFilterChain(ServletContext servletContext) { insertFilters(servletContext, new MultipartFilter()); } }
To ensure MultipartFilter is specified before the Spring Security filter with XML configuration, users can ensure the <filter-mapping> element of the MultipartFilter is placed before the springSecurityFilterChain within the web.xml as shown below:
<filter> <filter-name>MultipartFilter</filter-name> <filter-class>org.springframework.web.multipart.support.MultipartFilter</filter-class> </filter> <filter> <filter-name>springSecurityFilterChain</filter-name> <filter-class>org.springframework.web.filter.DelegatingFilterProxy</filter-class> </filter> <filter-mapping> <filter-name>MultipartFilter</filter-name> <url-pattern>/*</url-pattern> </filter-mapping> <filter-mapping> <filter-name>springSecurityFilterChain</filter-name> <url-pattern>/*</url-pattern> </filter-mapping>
If allowing unauthorized users to upload temporariy files is not acceptable, an alternative is to place the MultipartFilter after the Spring Security filter and include the CSRF as a query parameter in the action attribute of the form. An example with a jsp is shown below
<form action="./upload?${_csrf.parameterName}=${_csrf.token}" method="post" enctype="multipart/form-data">
The disadvantage to this approach is that query parameters can be leaked. More genearlly, it is considered best practice to place sensitive data within the body or headers to ensure it is not leaked. Additional information can be found in RFC 2616 Section 15.1.3 Encoding Sensitive Information in URI’s.
The HiddenHttpMethodFilter should be placed before the Spring Security filter. In general this is true, but it could have additional implications when protecting against CSRF attacks.
Note that the HiddenHttpMethodFilter only overrides the HTTP method on a POST, so this is actually unlikely to cause any real problems. However, it is still best practice to ensure it is placed before Spring Security’s filters.
Spring Security’s goal is to provide defaults that protect your users from exploits. This does not mean that you are forced to accept all of its defaults.
For example, you can provide a custom CsrfTokenRepository to override the way in which the CsrfToken is stored.
You can also specify a custom RequestMatcher to determine which requests are protected by CSRF (i.e. perhaps you don’t care if log out is exploited). In short, if Spring Security’s CSRF protection doesn’t behave exactly as you want it, you are able to customize the behavior. Refer to the Section 41.1.17, “<csrf>” documentation for details on how to make these customizations with XML and the CsrfConfigurer javadoc for details on how to make these customizations when using Java configuration.
Spring Framework provides first class support for CORS.
CORS must be processed before Spring Security because the preflight request will not contain any cookies (i.e. the JSESSIONID).
If the request does not contain any cookies and Spring Security is first, the request will determine the user is not authenticated (since there are no cookies in the request) and reject it.
The easiest way to ensure that CORS is handled first is to use the CorsFilter.
Users can integrate the CorsFilter with Spring Security by providing a CorsConfigurationSource using the following:
@EnableWebSecurity public class WebSecurityConfig extends WebSecurityConfigurerAdapter { @Override protected void configure(HttpSecurity http) throws Exception { http // by default uses a Bean by the name of corsConfigurationSource .cors().and() ... } @Bean CorsConfigurationSource corsConfigurationSource() { CorsConfiguration configuration = new CorsConfiguration(); configuration.setAllowedOrigins(Arrays.asList("https://example.com")); configuration.setAllowedMethods(Arrays.asList("GET","POST")); UrlBasedCorsConfigurationSource source = new UrlBasedCorsConfigurationSource(); source.registerCorsConfiguration("/**", configuration); return source; } }
or in XML
<http> <cors configuration-source-ref="corsSource"/> ... </http> <b:bean id="corsSource" class="org.springframework.web.cors.UrlBasedCorsConfigurationSource"> ... </b:bean>
If you are using Spring MVC’s CORS support, you can omit specifying the CorsConfigurationSource and Spring Security will leverage the CORS configuration provided to Spring MVC.
@EnableWebSecurity public class WebSecurityConfig extends WebSecurityConfigurerAdapter { @Override protected void configure(HttpSecurity http) throws Exception { http // if Spring MVC is on classpath and no CorsConfigurationSource is provided, // Spring Security will use CORS configuration provided to Spring MVC .cors().and() ... } }
or in XML
<http> <!-- Default to Spring MVC's CORS configuraiton --> <cors /> ... </http>
This section discusses Spring Security’s support for adding various security headers to the response.
Spring Security allows users to easily inject the default security headers to assist in protecting their application. The default for Spring Security is to include the following headers:
Cache-Control: no-cache, no-store, max-age=0, must-revalidate Pragma: no-cache Expires: 0 X-Content-Type-Options: nosniff Strict-Transport-Security: max-age=31536000 ; includeSubDomains X-Frame-Options: DENY X-XSS-Protection: 1; mode=block
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Strict-Transport-Security is only added on HTTPS requests |
For additional details on each of these headers, refer to the corresponding sections:
While each of these headers are considered best practice, it should be noted that not all clients utilize the headers, so additional testing is encouraged.
You can customize specific headers. For example, assume that want your HTTP response headers to look like the following:
Cache-Control: no-cache, no-store, max-age=0, must-revalidate Pragma: no-cache Expires: 0 X-Content-Type-Options: nosniff X-Frame-Options: SAMEORIGIN X-XSS-Protection: 1; mode=block
Specifically, you want all of the default headers with the following customizations:
- X-Frame-Options to allow any request from same domain
- HTTP Strict Transport Security (HSTS) will not be addded to the response
You can easily do this with the following Java Configuration:
@EnableWebSecurity public class WebSecurityConfig extends WebSecurityConfigurerAdapter { @Override protected void configure(HttpSecurity http) throws Exception { http // ... .headers() .frameOptions().sameOrigin() .httpStrictTransportSecurity().disable(); } }
Alternatively, if you are using Spring Security XML Configuration, you can use the following:
<http> <!-- ... --> <headers> <frame-options policy="SAMEORIGIN" /> <hsts disable="true"/> </headers> </http>
If you do not want the defaults to be added and want explicit control over what should be used, you can disable the defaults. An example for both Java and XML based configuration is provided below:
If you are using Spring Security’s Java Configuration the following will only add Cache Control.
@EnableWebSecurity public class WebSecurityConfig extends WebSecurityConfigurerAdapter { @Override protected void configure(HttpSecurity http) throws Exception { http // ... .headers() // do not use any default headers unless explicitly listed .defaultsDisabled() .cacheControl(); } }
The following XML will only add Cache Control.
<http> <!-- ... --> <headers defaults-disabled="true"> <cache-control/> </headers> </http>
If necessary, you can disable all of the HTTP Security response headers with the following Java Configuration:
@EnableWebSecurity public class WebSecurityConfig extends WebSecurityConfigurerAdapter { @Override protected void configure(HttpSecurity http) throws Exception { http // ... .headers().disable(); } }
If necessary, you can disable all of the HTTP Security response headers with the following XML configuration below:
<http> <!-- ... --> <headers disabled="true" /> </http>
In the past Spring Security required you to provide your own cache control for your web application. This seemed reasonable at the time, but browser caches have evolved to include caches for secure connections as well. This means that a user may view an authenticated page, log out, and then a malicious user can use the browser history to view the cached page. To help mitigate this Spring Security has added cache control support which will insert the following headers into you response.
Cache-Control: no-cache, no-store, max-age=0, must-revalidate Pragma: no-cache Expires: 0
Simply adding the <headers> element with no child elements will automatically add Cache Control and quite a few other protections. However, if you only want cache control, you can enable this feature using Spring Security’s XML namespace with the <cache-control> element and the headers@defaults-disabled attribute.
<http> <!-- ... --> <headers defaults-disable="true"> <cache-control /> </headers> </http>
Similarly, you can enable only cache control within Java Configuration with the following:
@EnableWebSecurity public class WebSecurityConfig extends WebSecurityConfigurerAdapter { @Override protected void configure(HttpSecurity http) throws Exception { http // ... .headers() .defaultsDisabled() .cacheControl(); } }
If you actually want to cache specific responses, your application can selectively invoke HttpServletResponse.setHeader(String,String) to override the header set by Spring Security. This is useful to ensure things like CSS, JavaScript, and images are properly cached.
When using Spring Web MVC, this is typically done within your configuration. For example, the following configuration will ensure that the cache headers are set for all of your resources:
@EnableWebMvc public class WebMvcConfiguration extends WebMvcConfigurerAdapter { @Override public void addResourceHandlers(ResourceHandlerRegistry registry) { registry .addResourceHandler("/resources/**") .addResourceLocations("/resources/") .setCachePeriod(31556926); } // ... }
Historically browsers, including Internet Explorer, would try to guess the content type of a request using content sniffing. This allowed browsers to improve the user experience by guessing the content type on resources that had not specified the content type. For example, if a browser encountered a JavaScript file that did not have the content type specified, it would be able to guess the content type and then execute it.
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There are many additional things one should do (i.e. only display the document in a distinct domain, ensure Content-Type header is set, sanitize the document, etc) when allowing content to be uploaded. However, these measures are out of the scope of what Spring Security provides. It is also important to point out when disabling content sniffing, you must specify the content type in order for things to work properly. |
The problem with content sniffing is that this allowed malicious users to use polyglots (i.e. a file that is valid as multiple content types) to execute XSS attacks. For example, some sites may allow users to submit a valid postscript document to a website and view it. A malicious user might create a postscript document that is also a valid JavaScript file and execute a XSS attack with it.
Content sniffing can be disabled by adding the following header to our response:
X-Content-Type-Options: nosniff
Just as with the cache control element, the nosniff directive is added by default when using the <headers> element with no child elements. However, if you want more control over which headers are added you can use the <content-type-options> element and the headers@defaults-disabled attribute as shown below:
<http> <!-- ... --> <headers defaults-disabled="true"> <content-type-options /> </headers> </http>
The X-Content-Type-Options header is added by default with Spring Security Java configuration. If you want more control over the headers, you can explicitly specify the content type options with the following:
@EnableWebSecurity public class WebSecurityConfig extends WebSecurityConfigurerAdapter { @Override protected void configure(HttpSecurity http) throws Exception { http // ... .headers() .defaultsDisabled() .contentTypeOptions(); } }
When you type in your bank’s website, do you enter mybank.example.com or do you enter https://mybank.example.com? If you omit the https protocol, you are potentially vulnerable to Man in the Middle attacks. Even if the website performs a redirect to https://mybank.example.com a malicious user could intercept the initial HTTP request and manipulate the response (i.e. redirect to https://mibank.example.com and steal their credentials).
Many users omit the https protocol and this is why HTTP Strict Transport Security (HSTS) was created. Once mybank.example.com is added as a HSTS host, a browser can know ahead of time that any request to mybank.example.com should be interpreted as https://mybank.example.com. This greatly reduces the possibility of a Man in the Middle attack occurring.
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In accordance with RFC6797, the HSTS header is only injected into HTTPS responses. In order for the browser to acknowledge the header, the browser must first trust the CA that signed the SSL certificate used to make the connection (not just the SSL certificate). |
One way for a site to be marked as a HSTS host is to have the host preloaded into the browser. Another is to add the "Strict-Transport-Security" header to the response. For example the following would instruct the browser to treat the domain as an HSTS host for a year (there are approximately 31536000 seconds in a year):
Strict-Transport-Security: max-age=31536000 ; includeSubDomains
The optional includeSubDomains directive instructs Spring Security that subdomains (i.e. secure.mybank.example.com) should also be treated as an HSTS domain.
As with the other headers, Spring Security adds HSTS by default. You can customize HSTS headers with the <hsts> element as shown below:
<http> <!-- ... --> <headers> <hsts include-subdomains="true" max-age-seconds="31536000" /> </headers> </http>
Similarly, you can enable only HSTS headers with Java Configuration:
@EnableWebSecurity public class WebSecurityConfig extends WebSecurityConfigurerAdapter { @Override protected void configure(HttpSecurity http) throws Exception { http // ... .headers() .httpStrictTransportSecurity() .includeSubdomains(true) .maxAgeSeconds(31536000); } }
HTTP Public Key Pinning (HPKP) is a security feature that tells a web client to associate a specific cryptographic public key with a certain web server to prevent Man in the Middle (MITM) attacks with forged certificates.
To ensure the authenticity of a server’s public key used in TLS sessions, this public key is wrapped into a X.509 certificate which is usually signed by a certificate authority (CA). Web clients such as browsers trust a lot of these CAs, which can all create certificates for arbitrary domain names. If an attacker is able to compromise a single CA, they can perform MITM attacks on various TLS connections. HPKP can circumvent this threat for the HTTPS protocol by telling the client which public key belongs to a certain web server. HPKP is a Trust on First Use (TOFU) technique. The first time a web server tells a client via a special HTTP header which public keys belong to it, the client stores this information for a given period of time. When the client visits the server again, it expects a certificate containing a public key whose fingerprint is already known via HPKP. If the server delivers an unknown public key, the client should present a warning to the user.
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Because the user-agent needs to validate the pins against the SSL certificate chain, the HPKP header is only injected into HTTPS responses. |
Enabling this feature for your site is as simple as returning the Public-Key-Pins HTTP header when your site is accessed over HTTPS. For example, the following would instruct the user-agent to only report pin validation failures to a given URI (via the report-uri directive) for 2 pins:
Public-Key-Pins-Report-Only: max-age=5184000 ; pin-sha256="d6qzRu9zOECb90Uez27xWltNsj0e1Md7GkYYkVoZWmM=" ; pin-sha256="E9CZ9INDbd+2eRQozYqqbQ2yXLVKB9+xcprMF+44U1g=" ; report-uri="http://example.net/pkp-report" ; includeSubDomains
A pin validation failure report is a standard JSON structure that can be captured either by the web application’s own API or by a publicly hosted HPKP reporting service, such as, REPORT-URI.
The optional includeSubDomains directive instructs the browser to also validate subdomains with the given pins.
Opposed to the other headers, Spring Security does not add HPKP by default. You can customize HPKP headers with the <hpkp> element as shown below:
<http> <!-- ... --> <headers> <hpkp include-subdomains="true" report-uri="http://example.net/pkp-report"> <pins> <pin algorithm="sha256">d6qzRu9zOECb90Uez27xWltNsj0e1Md7GkYYkVoZWmM=</pin> <pin algorithm="sha256">E9CZ9INDbd+2eRQozYqqbQ2yXLVKB9+xcprMF+44U1g=</pin> </pins> </hpkp> </headers> </http>
Similarly, you can enable HPKP headers with Java Configuration:
@EnableWebSecurity public class WebSecurityConfig extends WebSecurityConfigurerAdapter { @Override protected void configure(HttpSecurity http) throws Exception { http // ... .headers() .httpPublicKeyPinning() .includeSubdomains(true) .reportUri("http://example.net/pkp-report") .addSha256Pins("d6qzRu9zOECb90Uez27xWltNsj0e1Md7GkYYkVoZWmM=", "E9CZ9INDbd+2eRQozYqqbQ2yXLVKB9+xcprMF+44U1g="; } }
Allowing your website to be added to a frame can be a security issue. For example, using clever CSS styling users could be tricked into clicking on something that they were not intending (video demo). For example, a user that is logged into their bank might click a button that grants access to other users. This sort of attack is known as Clickjacking.
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Another modern approach to dealing with clickjacking is to use ???. |
There are a number ways to mitigate clickjacking attacks. For example, to protect legacy browsers from clickjacking attacks you can use frame breaking code. While not perfect, the frame breaking code is the best you can do for the legacy browsers.
A more modern approach to address clickjacking is to use X-Frame-Options header:
X-Frame-Options: DENY
The X-Frame-Options response header instructs the browser to prevent any site with this header in the response from being rendered within a frame. By default, Spring Security disables rendering within an iframe.
You can customize X-Frame-Options with the frame-options element. For example, the following will instruct Spring Security to use "X-Frame-Options: SAMEORIGIN" which allows iframes within the same domain:
<http> <!-- ... --> <headers> <frame-options policy="SAMEORIGIN" /> </headers> </http>
Similarly, you can customize frame options to use the same origin within Java Configuration using the following:
@EnableWebSecurity public class WebSecurityConfig extends WebSecurityConfigurerAdapter { @Override protected void configure(HttpSecurity http) throws Exception { http // ... .headers() .frameOptions() .sameOrigin(); } }
Some browsers have built in support for filtering out reflected XSS attacks. This is by no means full proof, but does assist in XSS protection.
The filtering is typically enabled by default, so adding the header typically just ensures it is enabled and instructs the browser what to do when a XSS attack is detected. For example, the filter might try to change the content in the least invasive way to still render everything. At times, this type of replacement can become a XSS vulnerability in itself. Instead, it is best to block the content rather than attempt to fix it. To do this we can add the following header:
X-XSS-Protection: 1; mode=block
This header is included by default. However, we can customize it if we wanted. For example:
<http> <!-- ... --> <headers> <xss-protection block="false"/> </headers> </http>
Similarly, you can customize xss protection within Java Configuration with the following:
@EnableWebSecurity public class WebSecurityConfig extends WebSecurityConfigurerAdapter { @Override protected void configure(HttpSecurity http) throws Exception { http // ... .headers() .xssProtection() .block(false); } }
Content Security Policy (CSP) is a mechanism that web applications can leverage to mitigate content injection vulnerabilities, such as cross-site scripting (XSS). CSP is a declarative policy that provides a facility for web application authors to declare and ultimately inform the client (user-agent) about the sources from which the web application expects to load resources.
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Content Security Policy is not intended to solve all content injection vulnerabilities. Instead, CSP can be leveraged to help reduce the harm caused by content injection attacks. As a first line of defense, web application authors should validate their input and encode their output. |
A web application may employ the use of CSP by including one of the following HTTP headers in the response:
- Content-Security-Policy
- Content-Security-Policy-Report-Only
Each of these headers are used as a mechanism to deliver a security policy to the client. A security policy contains a set of security policy directives (for example, script-src and object-src), each responsible for declaring the restrictions for a particular resource representation.
For example, a web application can declare that it expects to load scripts from specific, trusted sources, by including the following header in the response:
Content-Security-Policy: script-src https://trustedscripts.example.com
An attempt to load a script from another source other than what is declared in the script-src directive will be blocked by the user-agent. Additionally, if the report-uri directive is declared in the security policy, then the violation will be reported by the user-agent to the declared URL.
For example, if a web application violates the declared security policy, the following response header will instruct the user-agent to send violation reports to the URL specified in the policy’s report-uri directive.
Content-Security-Policy: script-src https://trustedscripts.example.com; report-uri /csp-report-endpoint/
Violation reports are standard JSON structures that can be captured either by the web application’s own API or by a publicly hosted CSP violation reporting service, such as, REPORT-URI.
The Content-Security-Policy-Report-Only header provides the capability for web application authors and administrators to monitor security policies, rather than enforce them. This header is typically used when experimenting and/or developing security policies for a site. When a policy is deemed effective, it can be enforced by using the Content-Security-Policy header field instead.
Given the following response header, the policy declares that scripts may be loaded from one of two possible sources.
Content-Security-Policy-Report-Only: script-src 'self' https://trustedscripts.example.com; report-uri /csp-report-endpoint/
If the site violates this policy, by attempting to load a script from evil.com, the user-agent will send a violation report to the declared URL specified by the report-uri directive, but still allow the violating resource to load nevertheless.
It’s important to note that Spring Security does not add Content Security Policy by default. The web application author must declare the security policy(s) to enforce and/or monitor for the protected resources.
For example, given the following security policy:
script-src 'self' https://trustedscripts.example.com; object-src https://trustedplugins.example.com; report-uri /csp-report-endpoint/
You can enable the CSP header using XML configuration with the <content-security-policy> element as shown below:
<http> <!-- ... --> <headers> <content-security-policy policy-directives="script-src 'self' https://trustedscripts.example.com; object-src https://trustedplugins.example.com; report-uri /csp-report-endpoint/" /> </headers> </http>
To enable the CSP 'report-only' header, configure the element as follows:
<http> <!-- ... --> <headers> <content-security-policy policy-directives="script-src 'self' https://trustedscripts.example.com; object-src https://trustedplugins.example.com; report-uri /csp-report-endpoint/" report-only="true" /> </headers> </http>
Similarly, you can enable the CSP header using Java configuration as shown below:
@EnableWebSecurity public class WebSecurityConfig extends WebSecurityConfigurerAdapter { @Override protected void configure(HttpSecurity http) throws Exception { http // ... .headers() .contentSecurityPolicy("script-src 'self' https://trustedscripts.example.com; object-src https://trustedplugins.example.com; report-uri /csp-report-endpoint/"); } }
To enable the CSP 'report-only' header, provide the following Java configuration:
@EnableWebSecurity public class WebSecurityConfig extends WebSecurityConfigurerAdapter { @Override protected void configure(HttpSecurity http) throws Exception { http // ... .headers() .contentSecurityPolicy("script-src 'self' https://trustedscripts.example.com; object-src https://trustedplugins.example.com; report-uri /csp-report-endpoint/") .reportOnly(); } }
Applying Content Security Policy to a web application is often a non-trivial undertaking. The following resources may provide further assistance in developing effective security policies for your site.
An Introduction to Content Security Policy
Spring Security has mechanisms to make it convenient to add the more common security headers to your application. However, it also provides hooks to enable adding custom headers.
There may be times you wish to inject custom security headers into your application that are not supported out of the box. For example, given the following custom security header:
X-Custom-Security-Header: header-value
When using the XML namespace, these headers can be added to the response using the <header> element as shown below:
<http> <!-- ... --> <headers> <header name="X-Custom-Security-Header" value="header-value"/> </headers> </http>
Similarly, the headers could be added to the response using Java Configuration as shown in the following:
@EnableWebSecurity public class WebSecurityConfig extends WebSecurityConfigurerAdapter { @Override protected void configure(HttpSecurity http) throws Exception { http // ... .headers() .addHeaderWriter(new StaticHeadersWriter("X-Custom-Security-Header","header-value")); } }
When the namespace or Java configuration does not support the headers you want, you can create a custom HeadersWriter instance or even provide a custom implementation of the HeadersWriter.
Let’s take a look at an example of using an custom instance of XFrameOptionsHeaderWriter. Perhaps you want to allow framing of content for the same origin. This is easily supported by setting the policy attribute to "SAMEORIGIN", but let’s take a look at a more explicit example using the ref attribute.
<http> <!-- ... --> <headers> <header ref="frameOptionsWriter"/> </headers> </http> <!-- Requires the c-namespace. See http://docs.spring.io/spring/docs/current/spring-framework-reference/htmlsingle/#beans-c-namespace --> <beans:bean id="frameOptionsWriter" class="org.springframework.security.web.header.writers.frameoptions.XFrameOptionsHeaderWriter" c:frameOptionsMode="SAMEORIGIN"/>
We could also restrict framing of content to the same origin with Java configuration:
@EnableWebSecurity public class WebSecurityConfig extends WebSecurityConfigurerAdapter { @Override protected void configure(HttpSecurity http) throws Exception { http // ... .headers() .addHeaderWriter(new XFrameOptionsHeaderWriter(XFrameOptionsMode.SAMEORIGIN)); } }
At times you may want to only write a header for certain requests. For example, perhaps you want to only protect your log in page from being framed. You could use the DelegatingRequestMatcherHeaderWriter to do so. When using the XML namespace configuration, this can be done with the following:
<http> <!-- ... --> <headers> <frame-options disabled="true"/> <header ref="headerWriter"/> </headers> </http> <beans:bean id="headerWriter" class="org.springframework.security.web.header.writers.DelegatingRequestMatcherHeaderWriter"> <beans:constructor-arg> <bean class="org.springframework.security.web.util.matcher.AntPathRequestMatcher" c:pattern="/login"/> </beans:constructor-arg> <beans:constructor-arg> <beans:bean class="org.springframework.security.web.header.writers.frameoptions.XFrameOptionsHeaderWriter"/> </beans:constructor-arg> </beans:bean>
We could also prevent framing of content to the log in page using java configuration:
@EnableWebSecurity public class WebSecurityConfig extends WebSecurityConfigurerAdapter { @Override protected void configure(HttpSecurity http) throws Exception { RequestMatcher matcher = new AntPathRequestMatcher("/login"); DelegatingRequestMatcherHeaderWriter headerWriter = new DelegatingRequestMatcherHeaderWriter(matcher,new XFrameOptionsHeaderWriter()); http // ... .headers() .frameOptions().disabled() .addHeaderWriter(headerWriter); } }
HTTP session related functonality is handled by a combination of the SessionManagementFilter and the SessionAuthenticationStrategy interface, which the filter delegates to. Typical usage includes session-fixation protection attack prevention, detection of session timeouts and restrictions on how many sessions an authenticated user may have open concurrently.
The SessionManagementFilter checks the contents of the SecurityContextRepository against the current contents of the SecurityContextHolder to determine whether a user has been authenticated during the current request, typically by a non-interactive authentication mechanism, such as pre-authentication or remember-me [17]. If the repository contains a security context, the filter does nothing. If it doesn’t, and the thread-local SecurityContext contains a (non-anonymous) Authentication object, the filter assumes they have been authenticated by a previous filter in the stack. It will then invoke the configured SessionAuthenticationStrategy.
If the user is not currently authenticated, the filter will check whether an invalid session ID has been requested (because of a timeout, for example) and will invoke the configured InvalidSessionStrategy, if one is set. The most common behaviour is just to redirect to a fixed URL and this is encapsulated in the standard implementation SimpleRedirectInvalidSessionStrategy. The latter is also used when configuring an invalid session URL through the namespace,as described earlier.
SessionAuthenticationStrategy is used by both SessionManagementFilter and AbstractAuthenticationProcessingFilter, so if you are using a customized form-login class, for example, you will need to inject it into both of these. In this case, a typical configuration, combining the namespace and custom beans might look like this:
<http> <custom-filter position="FORM_LOGIN_FILTER" ref="myAuthFilter" /> <session-management session-authentication-strategy-ref="sas"/> </http> <beans:bean id="myAuthFilter" class= "org.springframework.security.web.authentication.UsernamePasswordAuthenticationFilter"> <beans:property name="sessionAuthenticationStrategy" ref="sas" /> ... </beans:bean> <beans:bean id="sas" class= "org.springframework.security.web.authentication.session.SessionFixationProtectionStrategy" />
Note that the use of the default, SessionFixationProtectionStrategy may cause issues if you are storing beans in the session which implement HttpSessionBindingListener, including Spring session-scoped beans. See the Javadoc for this class for more information.
Spring Security is able to prevent a principal from concurrently authenticating to the same application more than a specified number of times. Many ISVs take advantage of this to enforce licensing, whilst network administrators like this feature because it helps prevent people from sharing login names. You can, for example, stop user"Batman" from logging onto the web application from two different sessions. You can either expire their previous login or you can report an error when they try to log in again, preventing the second login. Note that if you are using the second approach, a user who has not explicitly logged out (but who has just closed their browser, for example) will not be able to log in again until their original session expires.
Concurrency control is supported by the namespace, so please check the earlier namespace chapter for the simplest configuration. Sometimes you need to customize things though.
The implementation uses a specialized version of SessionAuthenticationStrategy, called ConcurrentSessionControlAuthenticationStrategy.
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Previously the concurrent authentication check was made by the |
To use concurrent session support, you’ll need to add the following to web.xml:
<listener> <listener-class> org.springframework.security.web.session.HttpSessionEventPublisher </listener-class> </listener>
In addition, you will need to add the ConcurrentSessionFilter to your FilterChainProxy. The ConcurrentSessionFilter requires two properties, sessionRegistry, which generally points to an instance of SessionRegistryImpl, and expiredUrl, which points to the page to display when a session has expired. A configuration using the namespace to create the FilterChainProxy and other default beans might look like this:
<http> <custom-filter position="CONCURRENT_SESSION_FILTER" ref="concurrencyFilter" /> <custom-filter position="FORM_LOGIN_FILTER" ref="myAuthFilter" /> <session-management session-authentication-strategy-ref="sas"/> </http> <beans:bean id="concurrencyFilter" class="org.springframework.security.web.session.ConcurrentSessionFilter"> <beans:property name="sessionRegistry" ref="sessionRegistry" /> <beans:property name="expiredUrl" value="/session-expired.htm" /> </beans:bean> <beans:bean id="myAuthFilter" class= "org.springframework.security.web.authentication.UsernamePasswordAuthenticationFilter"> <beans:property name="sessionAuthenticationStrategy" ref="sas" /> <beans:property name="authenticationManager" ref="authenticationManager" /> </beans:bean> <beans:bean id="sas" class="org.springframework.security.web.authentication.session.CompositeSessionAuthenticationStrategy"> <beans:constructor-arg> <beans:list> <beans:bean class="org.springframework.security.web.authentication.session.ConcurrentSessionControlAuthenticationStrategy"> <beans:constructor-arg ref="sessionRegistry"/> <beans:property name="maximumSessions" value="1" /> <beans:property name="exceptionIfMaximumExceeded" value="true" /> </beans:bean> <beans:bean class="org.springframework.security.web.authentication.session.SessionFixationProtectionStrategy"> </beans:bean> <beans:bean class="org.springframework.security.web.authentication.session.RegisterSessionAuthenticationStrategy"> <beans:constructor-arg ref="sessionRegistry"/> </beans:bean> </beans:list> </beans:constructor-arg> </beans:bean> <beans:bean id="sessionRegistry" class="org.springframework.security.core.session.SessionRegistryImpl" />
Adding the listener to web.xml causes an ApplicationEvent to be published to the Spring ApplicationContext every time a HttpSession commences or terminates. This is critical, as it allows the SessionRegistryImpl to be notified when a session ends. Without it, a user will never be able to log back in again once they have exceeded their session allowance, even if they log out of another session or it times out.
Setting up concurrency-control, either through the namespace or using plain beans has the useful side effect of providing you with a reference to the SessionRegistry which you can use directly within your application, so even if you don’t want to restrict the number of sessions a user may have, it may be worth setting up the infrastructure anyway. You can set the maximumSession property to -1 to allow unlimited sessions. If you’re using the namespace, you can set an alias for the internally-created SessionRegistry using the session-registry-alias attribute, providing a reference which you can inject into your own beans.
The getAllPrincipals() method supplies you with a list of the currently authenticated users. You can list a user’s sessions by calling the getAllSessions(Object principal, boolean includeExpiredSessions) method, which returns a list of SessionInformation objects. You can also expire a user’s session by calling expireNow() on a SessionInformation instance. When the user returns to the application, they will be prevented from proceeding. You may find these methods useful in an administration application, for example. Have a look at the Javadoc for more information.
[17] Authentication by mechanisms which perform a redirect after authenticating (such as form-login) will not be detected by SessionManagementFilter, as the filter will not be invoked during the authenticating request. Session-management functionality has to be handled separately in these cases.
It’s generally considered good security practice to adopt a "deny-by-default" where you explicitly specify what is allowed and disallow everything else. Defining what is accessible to unauthenticated users is a similar situation, particularly for web applications. Many sites require that users must be authenticated for anything other than a few URLs (for example the home and login pages). In this case it is easiest to define access configuration attributes for these specific URLs rather than have for every secured resource. Put differently, sometimes it is nice to say ROLE_SOMETHING is required by default and only allow certain exceptions to this rule, such as for login, logout and home pages of an application. You could also omit these pages from the filter chain entirely, thus bypassing the access control checks, but this may be undesirable for other reasons, particularly if the pages behave differently for authenticated users.
This is what we mean by anonymous authentication. Note that there is no real conceptual difference between a user who is "anonymously authenticated" and an unauthenticated user. Spring Security’s anonymous authentication just gives you a more convenient way to configure your access-control attributes. Calls to servlet API calls such as getCallerPrincipal, for example, will still return null even though there is actually an anonymous authentication object in the SecurityContextHolder.
There are other situations where anonymous authentication is useful, such as when an auditing interceptor queries the SecurityContextHolder to identify which principal was responsible for a given operation. Classes can be authored more robustly if they know the SecurityContextHolder always contains an Authentication object, and never null.
Anonymous authentication support is provided automatically when using the HTTP configuration Spring Security 3.0 and can be customized (or disabled) using the <anonymous> element. You don’t need to configure the beans described here unless you are using traditional bean configuration.
Three classes that together provide the anonymous authentication feature. AnonymousAuthenticationToken is an implementation of Authentication, and stores the GrantedAuthority s which apply to the anonymous principal. There is a corresponding AnonymousAuthenticationProvider, which is chained into the ProviderManager so that AnonymousAuthenticationToken s are accepted. Finally, there is an AnonymousAuthenticationFilter, which is chained after the normal authentication mechanisms and automatically adds an AnonymousAuthenticationToken to the SecurityContextHolder if there is no existing Authentication held there. The definition of the filter and authentication provider appears as follows:
<bean id="anonymousAuthFilter" class="org.springframework.security.web.authentication.AnonymousAuthenticationFilter"> <property name="key" value="foobar"/> <property name="userAttribute" value="anonymousUser,ROLE_ANONYMOUS"/> </bean> <bean id="anonymousAuthenticationProvider" class="org.springframework.security.authentication.AnonymousAuthenticationProvider"> <property name="key" value="foobar"/> </bean>
The key is shared between the filter and authentication provider, so that tokens created by the former are accepted by the latter [18]. The userAttribute is expressed in the form of usernameInTheAuthenticationToken,grantedAuthority[,grantedAuthority]. This is the same syntax as used after the equals sign for the userMap property of InMemoryDaoImpl.
As explained earlier, the benefit of anonymous authentication is that all URI patterns can have security applied to them. For example:
<bean id="filterSecurityInterceptor" class="org.springframework.security.web.access.intercept.FilterSecurityInterceptor"> <property name="authenticationManager" ref="authenticationManager"/> <property name="accessDecisionManager" ref="httpRequestAccessDecisionManager"/> <property name="securityMetadata"> <security:filter-security-metadata-source> <security:intercept-url pattern='/index.jsp' access='ROLE_ANONYMOUS,ROLE_USER'/> <security:intercept-url pattern='/hello.htm' access='ROLE_ANONYMOUS,ROLE_USER'/> <security:intercept-url pattern='/logoff.jsp' access='ROLE_ANONYMOUS,ROLE_USER'/> <security:intercept-url pattern='/login.jsp' access='ROLE_ANONYMOUS,ROLE_USER'/> <security:intercept-url pattern='/**' access='ROLE_USER'/> </security:filter-security-metadata-source>" + </property> </bean>
Rounding out the anonymous authentication discussion is the AuthenticationTrustResolver interface, with its corresponding AuthenticationTrustResolverImpl implementation. This interface provides an isAnonymous(Authentication) method, which allows interested classes to take into account this special type of authentication status. The ExceptionTranslationFilter uses this interface in processing AccessDeniedException s. If an AccessDeniedException is thrown, and the authentication is of an anonymous type, instead of throwing a 403 (forbidden) response, the filter will instead commence the AuthenticationEntryPoint so the principal can authenticate properly. This is a necessary distinction, otherwise principals would always be deemed "authenticated" and never be given an opportunity to login via form, basic, digest or some other normal authentication mechanism.
You will often see the ROLE_ANONYMOUS attribute in the above interceptor configuration replaced with IS_AUTHENTICATED_ANONYMOUSLY, which is effectively the same thing when defining access controls. This is an example of the use of the AuthenticatedVoter which we will see in the authorization chapter. It uses an AuthenticationTrustResolver to process this particular configuration attribute and grant access to anonymous users. the AuthenticatedVoter approach is more powerful, since it allows you to differentiate between anonymous, remember-me and fully-authenticated users. If you don’t need this functionality though, then you can stick with ROLE_ANONYMOUS, which will be processed by Spring Security’s standard RoleVoter.
[18] The use of the key property should not be regarded as providing any real security here. It is merely a book-keeping exercise. If you are sharing a ProviderManager which contains an AnonymousAuthenticationProvider in a scenario where it is possible for an authenticating client to construct the Authentication object (such as with RMI invocations), then a malicious client could submit an AnonymousAuthenticationToken which it had created itself (with chosen username and authority list). If the key is guessable or can be found out, then the token would be accepted by the anonymous provider. This isn’t a problem with normal usage but if you are using RMI you would be best to use a customized ProviderManager which omits the anonymous provider rather than sharing the one you use for your HTTP authentication mechanisms.
Spring Security 4 added support for securing Spring’s WebSocket support. This section describes how to use Spring Security’s WebSocket support.
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You can find a complete working sample of WebSocket security in samples/javaconfig/chat. |
Spring Security 4.0 has introduced authorization support for WebSockets through the Spring Messaging abstraction.
To configure authorization using Java Configuration, simply extend the AbstractSecurityWebSocketMessageBrokerConfigurer and configure the MessageSecurityMetadataSourceRegistry.
For example:
@Configuration public class WebSocketSecurityConfig extends AbstractSecurityWebSocketMessageBrokerConfigurer {
This will ensure that:
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Any inbound CONNECT message requires a valid CSRF token to enforce Same Origin Policy |
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The SecurityContextHolder is populated with the user within the simpUser header attribute for any inbound request. |
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Our messages require the proper authorization. Specifically, any inbound message that starts with "/user/" will require ROLE_USER. Additional details on authorization can be found in Section 23.3, “WebSocket Authorization” |
Spring Security also provides XML Namespace support for securing WebSockets. A comparable XML based configuration looks like the following:
<websocket-message-broker>
This will ensure that:
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Any inbound CONNECT message requires a valid CSRF token to enforce Same Origin Policy |
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The SecurityContextHolder is populated with the user within the simpUser header attribute for any inbound request. |
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Our messages require the proper authorization. Specifically, any inbound message that starts with "/user/" will require ROLE_USER. Additional details on authorization can be found in Section 23.3, “WebSocket Authorization” |
WebSockets reuse the same authentication information that is found in the HTTP request when the WebSocket connection was made.
This means that the Principal on the HttpServletRequest will be handed off to WebSockets.
If you are using Spring Security, the Principal on the HttpServletRequest is overridden automatically.
More concretely, to ensure a user has authenticated to your WebSocket application, all that is necessary is to ensure that you setup Spring Security to authenticate your HTTP based web application.
Spring Security 4.0 has introduced authorization support for WebSockets through the Spring Messaging abstraction.
To configure authorization using Java Configuration, simply extend the AbstractSecurityWebSocketMessageBrokerConfigurer and configure the MessageSecurityMetadataSourceRegistry.
For example:
@Configuration public class WebSocketSecurityConfig extends AbstractSecurityWebSocketMessageBrokerConfigurer { @Override protected void configureInbound(MessageSecurityMetadataSourceRegistry messages) { messages .nullDestMatcher().authenticated()
This will ensure that:
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Any message without a destination (i.e. anything other that Message type of MESSAGE or SUBSCRIBE) will require the user to be authenticated |
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Anyone can subscribe to /user/queue/errors |
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Any message that has a destination starting with "/app/" will be require the user to have the role ROLE_USER |
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Any message that starts with "/user/" or "/topic/friends/" that is of type SUBSCRIBE will require ROLE_USER |
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Any other message of type MESSAGE or SUBSCRIBE is rejected. Due to 6 we do not need this step, but it illustrates how one can match on specific message types. |
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Any other Message is rejected. This is a good idea to ensure that you do not miss any messages. |
Spring Security also provides XML Namespace support for securing WebSockets. A comparable XML based configuration looks like the following:
<websocket-message-broker>
This will ensure that:
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Any message of type CONNECT, UNSUBSCRIBE, or DISCONNECT will require the user to be authenticated |
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Anyone can subscribe to /user/queue/errors |
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Any message that has a destination starting with "/app/" will be require the user to have the role ROLE_USER |
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Any message that starts with "/user/" or "/topic/friends/" that is of type SUBSCRIBE will require ROLE_USER |
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Any other message of type MESSAGE or SUBSCRIBE is rejected. Due to 6 we do not need this step, but it illustrates how one can match on specific message types. |
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Any other message with a destination is rejected. This is a good idea to ensure that you do not miss any messages. |
In order to properly secure your application it is important to understand Spring’s WebSocket support.
It is important to understand the distinction between SUBSCRIBE and MESSAGE types of messages and how it works within Spring.
Consider a chat application.
- The system can send notifications MESSAGE to all users through a destination of "/topic/system/notifications"
- Clients can receive notifications by SUBSCRIBE to the "/topic/system/notifications".
While we want clients to be able to SUBSCRIBE to "/topic/system/notifications", we do not want to enable them to send a MESSAGE to that destination. If we allowed sending a MESSAGE to "/topic/system/notifications", then clients could send a message directly to that endpoint and impersonate the system.
In general, it is common for applications to deny any MESSAGE sent to a message that starts with the broker prefix (i.e. "/topic/" or "/queue/").
It is also is important to understand how destinations are transformed.
Consider a chat application.
- User’s can send messages to a specific user by sending a message to the destination of "/app/chat".
- The application sees the message, ensures that the "from" attribute is specified as the current user (we cannot trust the client).
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The application then sends the message to the recipient using
SimpMessageSendingOperations.convertAndSendToUser("toUser", "/queue/messages", message). - The message gets turned into the destination of "/queue/user/messages-<sessionid>"
With the application above, we want to allow our client to listen to "/user/queue" which is transformed into "/queue/user/messages-<sessionid>". However, we do not want the client to be able to listen to "/queue/*" because that would allow the client to see messages for every user.
In general, it is common for applications to deny any SUBSCRIBE sent to a message that starts with the broker prefix (i.e. "/topic/" or "/queue/"). Of course we may provide exceptions to account for things like
Spring contains a section titled Flow of Messages that describes how messages flow through the system.
It is important to note that Spring Security only secures the clientInboundChannel.
Spring Security does not attempt to secure the clientOutboundChannel.
The most important reason for this is performance. For every message that goes in, there are typically many more that go out. Instead of securing the outbound messages, we encourage securing the subscription to the endpoints.
It is important to emphasize that the browser does not enforce the Same Origin Policy for WebSocket connections. This is an extremely important consideration.
Consider the following scenario. A user visits bank.com and authenticates to their account. The same user opens another tab in their browser and visits evil.com. The Same Origin Policy ensures that evil.com cannot read or write data to bank.com.
With WebSockets the Same Origin Policy does not apply. In fact, unless bank.com explicitly forbids it, evil.com can read and write data on behalf of the user. This means that anything the user can do over the websocket (i.e. transfer money), evil.com can do on that users behalf.
Since SockJS tries to emulate WebSockets it also bypasses the Same Origin Policy. This means developers need to explicitly protect their applications from external domains when using SockJS.
Fortunately, since Spring 4.1.5 Spring’s WebSocket and SockJS support restricts access to the current domain. Spring Security adds an additional layer of protection to provide defence in depth.
By default Spring Security requires the CSRF token in any CONNECT message type. This ensures that only a site that has access to the CSRF token can connect. Since only the Same Origin can access the CSRF token, external domains are not allowed to make a connection.
Typically we need to include the CSRF token in an HTTP header or an HTTP parameter. However, SockJS does not allow for these options. Instead, we must include the token in the Stomp headers
Applications can obtain a CSRF token by accessing the request attribute named _csrf.
For example, the following will allow accessing the CsrfToken in a JSP:
var headerName = "${_csrf.headerName}"; var token = "${_csrf.token}";
If you are using static HTML, you can expose the CsrfToken on a REST endpoint.
For example, the following would expose the CsrfToken on the URL /csrf
@RestController public class CsrfController { @RequestMapping("/csrf") public CsrfToken csrf(CsrfToken token) { return token; } }
The javascript can make a REST call to the endpoint and use the response to populate the headerName and the token.
We can now include the token in our Stomp client. For example:
... var headers = {}; headers[headerName] = token; stompClient.connect(headers, function(frame) { ... }
If you want to allow other domains to access your site, you can disable Spring Security’s protection. For example, in Java Configuration you can use the following:
@Configuration public class WebSocketSecurityConfig extends AbstractSecurityWebSocketMessageBrokerConfigurer { ... @Override protected boolean sameOriginDisabled() { return true; } }
SockJS provides fallback transports to support older browsers. When using the fallback options we need to relax a few security constraints to allow SockJS to work with Spring Security.
SockJS may use an transport that leverages an iframe. By default Spring Security will deny the site from being framed to prevent Clickjacking attacks. To allow SockJS frame based transports to work, we need to configure Spring Security to allow the same origin to frame the content.
You can customize X-Frame-Options with the frame-options element. For example, the following will instruct Spring Security to use "X-Frame-Options: SAMEORIGIN" which allows iframes within the same domain:
<http> <!-- ... --> <headers> <frame-options policy="SAMEORIGIN" /> </headers> </http>
Similarly, you can customize frame options to use the same origin within Java Configuration using the following:
@EnableWebSecurity public class WebSecurityConfig extends WebSecurityConfigurerAdapter { @Override protected void configure(HttpSecurity http) throws Exception { http // ... .headers() .frameOptions() .sameOrigin(); } }
SockJS uses a POST on the CONNECT messages for any HTTP based transport. Typically we need to include the CSRF token in an HTTP header or an HTTP parameter. However, SockJS does not allow for these options. Instead, we must include the token in the Stomp headers as described in Section 23.4.3, “Adding CSRF to Stomp Headers”.
It also means we need to relax our CSRF protection with the web layer. Specifically, we want to disable CSRF protection for our connect URLs. We do NOT want to disable CSRF protection for every URL. Otherwise our site will be vulnerable to CSRF attacks.
We can easily achieve this by providing a CSRF RequestMatcher. Our Java Configuration makes this extremely easy. For example, if our stomp endpoint is "/chat" we can disable CSRF protection for only URLs that start with "/chat/" using the following configuration:
@Configuration @EnableWebSecurity public class WebSecurityConfig extends WebSecurityConfigurerAdapter { @Override protected void configure(HttpSecurity http) throws Exception { http .csrf() // ignore our stomp endpoints since they are protected using Stomp headers .ignoringAntMatchers("/chat/**") .and() .headers() // allow same origin to frame our site to support iframe SockJS .frameOptions().sameOrigin() .and() .authorizeRequests() ...
If we are using XML based configuration, we can use the csrf@request-matcher-ref. For example:
<http ...> <csrf request-matcher-ref="csrfMatcher"/> <headers> <frame-options policy="SAMEORIGIN"/> </headers> ... </http> <b:bean id="csrfMatcher" class="AndRequestMatcher"> <b:constructor-arg value="#{T(org.springframework.security.web.csrf.CsrfFilter).DEFAULT_CSRF_MATCHER}"/> <b:constructor-arg> <b:bean class="org.springframework.security.web.util.matcher.NegatedRequestMatcher"> <b:bean class="org.springframework.security.web.util.matcher.AntPathRequestMatcher"> <b:constructor-arg value="/chat/**"/> </b:bean> </b:bean> </b:constructor-arg> </b:bean>
The advanced authorization capabilities within Spring Security represent one of the most compelling reasons for its popularity. Irrespective of how you choose to authenticate - whether using a Spring Security-provided mechanism and provider, or integrating with a container or other non-Spring Security authentication authority - you will find the authorization services can be used within your application in a consistent and simple way.
In this part we’ll explore the different AbstractSecurityInterceptor implementations, which were introduced in Part I. We then move on to explore how to fine-tune authorization through use of domain access control lists.
As we saw in the technical overview, all Authentication implementations store a list of GrantedAuthority objects. These represent the authorities that have been granted to the principal. the GrantedAuthority objects are inserted into the Authentication object by the AuthenticationManager and are later read by AccessDecisionManager s when making authorization decisions.
GrantedAuthority is an interface with only one method:
String getAuthority();
This method allows
AccessDecisionManager s to obtain a precise String representation of the GrantedAuthority. By returning a representation as a String, a GrantedAuthority can be easily "read" by most AccessDecisionManager s. If a GrantedAuthority cannot be precisely represented as a String, the GrantedAuthority is considered "complex" and getAuthority() must return null.
An example of a "complex" GrantedAuthority would be an implementation that stores a list of operations and authority thresholds that apply to different customer account numbers. Representing this complex GrantedAuthority as a String would be quite difficult, and as a result the getAuthority() method should return null. This will indicate to any AccessDecisionManager that it will need to specifically support the GrantedAuthority implementation in order to understand its contents.
Spring Security includes one concrete GrantedAuthority implementation, GrantedAuthorityImpl. This allows any user-specified String to be converted into a GrantedAuthority. All AuthenticationProvider s included with the security architecture use GrantedAuthorityImpl to populate the Authentication object.
As we’ve also seen in the Technical Overview chapter, Spring Security provides interceptors which control access to secure objects such as method invocations or web requests. A pre-invocation decision on whether the invocation is allowed to proceed is made by the AccessDecisionManager.
The AccessDecisionManager is called by the AbstractSecurityInterceptor and is responsible for making final access control decisions. the AccessDecisionManager interface contains three methods:
void decide(Authentication authentication, Object secureObject, Collection<ConfigAttribute> attrs) throws AccessDeniedException; boolean supports(ConfigAttribute attribute); boolean supports(Class clazz);
The AccessDecisionManager's decide method is passed all the relevant information it needs in order to make an authorization decision. In particular, passing the secure Object enables those arguments contained in the actual secure object invocation to be inspected. For example, let’s assume the secure object was a MethodInvocation. It would be easy to query the MethodInvocation for any Customer argument, and then implement some sort of security logic in the AccessDecisionManager to ensure the principal is permitted to operate on that customer. Implementations are expected to throw an AccessDeniedException if access is denied.
The supports(ConfigAttribute) method is called by the AbstractSecurityInterceptor at startup time to determine if the AccessDecisionManager can process the passed ConfigAttribute. The supports(Class) method is called by a security interceptor implementation to ensure the configured AccessDecisionManager supports the type of secure object that the security interceptor will present.
Whilst users can implement their own AccessDecisionManager to control all aspects of authorization, Spring Security includes several AccessDecisionManager implementations that are based on voting. Figure 24.1, “Voting Decision Manager” illustrates the relevant classes.
Using this approach, a series of AccessDecisionVoter implementations are polled on an authorization decision. The AccessDecisionManager then decides whether or not to throw an AccessDeniedException based on its assessment of the votes.
The AccessDecisionVoter interface has three methods:
int vote(Authentication authentication, Object object, Collection<ConfigAttribute> attrs); boolean supports(ConfigAttribute attribute); boolean supports(Class clazz);
Concrete implementations return an int, with possible values being reflected in the AccessDecisionVoter static fields ACCESS_ABSTAIN, ACCESS_DENIED and ACCESS_GRANTED. A voting implementation will return ACCESS_ABSTAIN if it has no opinion on an authorization decision. If it does have an opinion, it must return either ACCESS_DENIED or ACCESS_GRANTED.
There are three concrete AccessDecisionManager s provided with Spring Security that tally the votes. the ConsensusBased implementation will grant or deny access based on the consensus of non-abstain votes. Properties are provided to control behavior in the event of an equality of votes or if all votes are abstain. The AffirmativeBased implementation will grant access if one or more ACCESS_GRANTED votes were received (i.e. a deny vote will be ignored, provided there was at least one grant vote). Like the ConsensusBased implementation, there is a parameter that controls the behavior if all voters abstain. The UnanimousBased provider expects unanimous ACCESS_GRANTED votes in order to grant access, ignoring abstains. It will deny access if there is any ACCESS_DENIED vote. Like the other implementations, there is a parameter that controls the behaviour if all voters abstain.
It is possible to implement a custom AccessDecisionManager that tallies votes differently. For example, votes from a particular AccessDecisionVoter might receive additional weighting, whilst a deny vote from a particular voter may have a veto effect.
The most commonly used AccessDecisionVoter provided with Spring Security is the simple RoleVoter, which treats configuration attributes as simple role names and votes to grant access if the user has been assigned that role.
It will vote if any ConfigAttribute begins with the prefix ROLE_. It will vote to grant access if there is a GrantedAuthority which returns a String representation (via the getAuthority() method) exactly equal to one or more ConfigAttributes starting with the prefix ROLE_. If there is no exact match of any ConfigAttribute starting with ROLE_, the RoleVoter will vote to deny access. If no ConfigAttribute begins with ROLE_, the voter will abstain.
Another voter which we’ve implicitly seen is the AuthenticatedVoter, which can be used to differentiate between anonymous, fully-authenticated and remember-me authenticated users. Many sites allow certain limited access under remember-me authentication, but require a user to confirm their identity by logging in for full access.
When we’ve used the attribute IS_AUTHENTICATED_ANONYMOUSLY to grant anonymous access, this attribute was being processed by the AuthenticatedVoter. See the Javadoc for this class for more information.
Obviously, you can also implement a custom AccessDecisionVoter and you can put just about any access-control logic you want in it. It might be specific to your application (business-logic related) or it might implement some security administration logic. For example, you’ll find a blog article on the Spring web site which describes how to use a voter to deny access in real-time to users whose accounts have been suspended.
Whilst the AccessDecisionManager is called by the AbstractSecurityInterceptor before proceeding with the secure object invocation, some applications need a way of modifying the object actually returned by the secure object invocation. Whilst you could easily implement your own AOP concern to achieve this, Spring Security provides a convenient hook that has several concrete implementations that integrate with its ACL capabilities.
Figure 24.2, “After Invocation Implementation” illustrates Spring Security’s AfterInvocationManager and its concrete implementations.
Like many other parts of Spring Security, AfterInvocationManager has a single concrete implementation, AfterInvocationProviderManager, which polls a list of AfterInvocationProvider s. Each AfterInvocationProvider is allowed to modify the return object or throw an AccessDeniedException. Indeed multiple providers can modify the object, as the result of the previous provider is passed to the next in the list.
Please be aware that if you’re using AfterInvocationManager, you will still need configuration attributes that allow the MethodSecurityInterceptor's AccessDecisionManager to allow an operation. If you’re using the typical Spring Security included AccessDecisionManager implementations, having no configuration attributes defined for a particular secure method invocation will cause each AccessDecisionVoter to abstain from voting. In turn, if the AccessDecisionManager property “allowIfAllAbstainDecisions” is false, an AccessDeniedException will be thrown. You may avoid this potential issue by either (i) setting “allowIfAllAbstainDecisions” to true (although this is generally not recommended) or (ii) simply ensure that there is at least one configuration attribute that an AccessDecisionVoter will vote to grant access for. This latter (recommended) approach is usually achieved through a ROLE_USER or ROLE_AUTHENTICATED configuration attribute.
It is a common requirement that a particular role in an application should automatically "include" other roles. For example, in an application which has the concept of an "admin" and a "user" role, you may want an admin to be able to do everything a normal user can. To achieve this, you can either make sure that all admin users are also assigned the "user" role. Alternatively, you can modify every access constraint which requires the "user" role to also include the "admin" role. This can get quite complicated if you have a lot of different roles in your application.
The use of a role-hierarchy allows you to configure which roles (or authorities) should include others. An extended version of Spring Security’s RoleVoter, RoleHierarchyVoter, is configured with a RoleHierarchy, from which it obtains all the "reachable authorities" which the user is assigned. A typical configuration might look like this:
<bean id="roleVoter" class="org.springframework.security.access.vote.RoleHierarchyVoter"> <constructor-arg ref="roleHierarchy" /> </bean> <bean id="roleHierarchy" class="org.springframework.security.access.hierarchicalroles.RoleHierarchyImpl"> <property name="hierarchy"> <value> ROLE_ADMIN > ROLE_STAFF ROLE_STAFF > ROLE_USER ROLE_USER > ROLE_GUEST </value> </property> </bean>
Here we have four roles in a hierarchy ROLE_ADMIN ⇒ ROLE_STAFF ⇒ ROLE_USER ⇒ ROLE_GUEST. A user who is authenticated with ROLE_ADMIN, will behave as if they have all four roles when security contraints are evaluated against an AccessDecisionManager cconfigured with the above RoleHierarchyVoter. The > symbol can be thought of as meaning "includes".
Role hierarchies offer a convenient means of simplifying the access-control configuration data for your application and/or reducing the number of authorities which you need to assign to a user. For more complex requirements you may wish to define a logical mapping between the specific access-rights your application requires and the roles that are assigned to users, translating between the two when loading the user information.
Prior to Spring Security 2.0, securing MethodInvocation s needed quite a lot of boiler plate configuration. Now the recommended approach for method security is to use namespace configuration. This way the method security infrastructure beans are configured automatically for you so you don’t really need to know about the implementation classes. We’ll just provide a quick overview of the classes that are involved here.
Method security in enforced using a MethodSecurityInterceptor, which secures MethodInvocation s. Depending on the configuration approach, an interceptor may be specific to a single bean or shared between multiple beans. The interceptor uses a MethodSecurityMetadataSource instance to obtain the configuration attributes that apply to a particular method invocation. MapBasedMethodSecurityMetadataSource is used to store configuration attributes keyed by method names (which can be wildcarded) and will be used internally when the attributes are defined in the application context using the <intercept-methods> or <protect-point> elements. Other implementations will be used to handle annotation-based configuration.
You can of course configure a MethodSecurityIterceptor directly in your application context for use with one of Spring AOP’s proxying mechanisms:
<bean id="bankManagerSecurity" class= "org.springframework.security.access.intercept.aopalliance.MethodSecurityInterceptor"> <property name="authenticationManager" ref="authenticationManager"/> <property name="accessDecisionManager" ref="accessDecisionManager"/> <property name="afterInvocationManager" ref="afterInvocationManager"/> <property name="securityMetadataSource"> <sec:method-security-metadata-source> <sec:protect method="com.mycompany.BankManager.delete*" access="ROLE_SUPERVISOR"/> <sec:protect method="com.mycompany.BankManager.getBalance" access="ROLE_TELLER,ROLE_SUPERVISOR"/> </sec:method-security-metadata-source> </property> </bean>
The AspectJ security interceptor is very similar to the AOP Alliance security interceptor discussed in the previous section. Indeed we will only discuss the differences in this section.
The AspectJ interceptor is named AspectJSecurityInterceptor. Unlike the AOP Alliance security interceptor, which relies on the Spring application context to weave in the security interceptor via proxying, the AspectJSecurityInterceptor is weaved in via the AspectJ compiler. It would not be uncommon to use both types of security interceptors in the same application, with AspectJSecurityInterceptor being used for domain object instance security and the AOP Alliance MethodSecurityInterceptor being used for services layer security.
Let’s first consider how the AspectJSecurityInterceptor is configured in the Spring application context:
<bean id="bankManagerSecurity" class= "org.springframework.security.access.intercept.aspectj.AspectJMethodSecurityInterceptor"> <property name="authenticationManager" ref="authenticationManager"/> <property name="accessDecisionManager" ref="accessDecisionManager"/> <property name="afterInvocationManager" ref="afterInvocationManager"/> <property name="securityMetadataSource"> <sec:method-security-metadata-source> <sec:protect method="com.mycompany.BankManager.delete*" access="ROLE_SUPERVISOR"/> <sec:protect method="com.mycompany.BankManager.getBalance" access="ROLE_TELLER,ROLE_SUPERVISOR"/> </sec:method-security-metadata-source> </property> </bean>
As you can see, aside from the class name, the AspectJSecurityInterceptor is exactly the same as the AOP Alliance security interceptor. Indeed the two interceptors can share the same securityMetadataSource, as the SecurityMetadataSource works with java.lang.reflect.Method s rather than an AOP library-specific class. Of course, your access decisions have access to the relevant AOP library-specific invocation (ie MethodInvocation or JoinPoint) and as such can consider a range of addition criteria when making access decisions (such as method arguments).
Next you’ll need to define an AspectJ aspect. For example:
package org.springframework.security.samples.aspectj; import org.springframework.security.access.intercept.aspectj.AspectJSecurityInterceptor; import org.springframework.security.access.intercept.aspectj.AspectJCallback; import org.springframework.beans.factory.InitializingBean; public aspect DomainObjectInstanceSecurityAspect implements InitializingBean { private AspectJSecurityInterceptor securityInterceptor; pointcut domainObjectInstanceExecution(): target(PersistableEntity) && execution(public * *(..)) && !within(DomainObjectInstanceSecurityAspect); Object around(): domainObjectInstanceExecution() { if (this.securityInterceptor == null) { return proceed(); } AspectJCallback callback = new AspectJCallback() { public Object proceedWithObject() { return proceed(); } }; return this.securityInterceptor.invoke(thisJoinPoint, callback); } public AspectJSecurityInterceptor getSecurityInterceptor() { return securityInterceptor; } public void setSecurityInterceptor(AspectJSecurityInterceptor securityInterceptor) { this.securityInterceptor = securityInterceptor; } public void afterPropertiesSet() throws Exception { if (this.securityInterceptor == null) throw new IllegalArgumentException("securityInterceptor required"); } } }
In the above example, the security interceptor will be applied to every instance of PersistableEntity, which is an abstract class not shown (you can use any other class or pointcut expression you like). For those curious, AspectJCallback is needed because the proceed(); statement has special meaning only within an around() body. The AspectJSecurityInterceptor calls this anonymous AspectJCallback class when it wants the target object to continue.
You will need to configure Spring to load the aspect and wire it with the AspectJSecurityInterceptor. A bean declaration which achieves this is shown below:
<bean id="domainObjectInstanceSecurityAspect" class="security.samples.aspectj.DomainObjectInstanceSecurityAspect" factory-method="aspectOf"> <property name="securityInterceptor" ref="bankManagerSecurity"/> </bean>
That’s it! Now you can create your beans from anywhere within your application, using whatever means you think fit (eg new Person();) and they will have the security interceptor applied.
Spring Security 3.0 introduced the ability to use Spring EL expressions as an authorization mechanism in addition to the simple use of configuration attributes and access-decision voters which have seen before. Expression-based access control is built on the same architecture but allows complicated boolean logic to be encapsulated in a single expression.
Spring Security uses Spring EL for expression support and you should look at how that works if you are interested in understanding the topic in more depth. Expressions are evaluated with a "root object" as part of the evaluation context. Spring Security uses specific classes for web and method security as the root object, in order to provide built-in expressions and access to values such as the current principal.
The base class for expression root objects is SecurityExpressionRoot. This provides some common expressions which are available in both web and method security.
Table 26.1. Common built-in expressions
| Expression | Description |
|---|---|
| Returns |
| Returns |
| Returns |
| Returns |
| Allows direct access to the principal object representing the current user |
| Allows direct access to the current |
| Always evaluates to |
| Always evaluates to |
| Returns |
| Returns |
| Returns |
| Returns |
| Returns |
| Returns |
To use expressions to secure individual URLs, you would first need to set the use-expressions attribute in the <http> element to true.
Spring Security will then expect the access attributes of the <intercept-url> elements to contain Spring EL expressions.
The expressions should evaluate to a boolean, defining whether access should be allowed or not.
For example:
<http> <intercept-url pattern="/admin*" access="hasRole('admin') and hasIpAddress('192.168.1.0/24')"/> ... </http>
Here we have defined that the "admin" area of an application (defined by the URL pattern) should only be available to users who have the granted authority "admin" and whose IP address matches a local subnet.
We’ve already seen the built-in hasRole expression in the previous section.
The expression hasIpAddress is an additional built-in expression which is specific to web security.
It is defined by the WebSecurityExpressionRoot class, an instance of which is used as the expression root object when evaluation web-access expressions.
This object also directly exposed the HttpServletRequest object under the name request so you can invoke the request directly in an expression.
If expressions are being used, a WebExpressionVoter will be added to the AccessDecisionManager which is used by the namespace.
So if you aren’t using the namespace and want to use expressions, you will have to add one of these to your configuration.
If you wish to extend the expressions that are available, you can easily refer to any Spring Bean you expose.
For example, assumming you have a Bean with the name of webSecurity that contains the following method signature:
public class WebSecurity { public boolean check(Authentication authentication, HttpServletRequest request) { ... } }
You could refer to the method using:
<http> <intercept-url pattern="/user/**" access="@webSecurity.check(authentication,request)"/> ... </http>
or in Java configuration
http .authorizeRequests() .antMatchers("/user/**").access("@webSecurity.check(authentication,request)") ...
At times it is nice to be able to refer to path variables within a URL.
For example, consider a RESTful application that looks up a user by id from the URL path in the format /user/{userId}.
You can easily refer to the path variable by placing it in the pattern.
For example, if you had a Bean with the name of webSecurity that contains the following method signature:
public class WebSecurity { public boolean checkUserId(Authentication authentication, int id) { ... } }
You could refer to the method using:
<http> <intercept-url pattern="/user/{userId}/**" access="@webSecurity.checkUserId(authentication,#userId)"/> ... </http>
or in Java configuration
http .authorizeRequests() .antMatchers("/user/{userId}/**").access("@webSecurity.checkUserId(authentication,#userId)") ...
In both configurations URLs that match would pass in the path variable (and convert it) into checkUserId method.
For example, if the URL were /user/123/resource, then the id passed in would be 123.
Method security is a bit more complicated than a simple allow or deny rule. Spring Security 3.0 introduced some new annotations in order to allow comprehensive support for the use of expressions.
There are four annotations which support expression attributes to allow pre and post-invocation authorization checks and also to support filtering of submitted collection arguments or return values. They are @PreAuthorize, @PreFilter, @PostAuthorize and @PostFilter. Their use is enabled through the global-method-security namespace element:
<global-method-security pre-post-annotations="enabled"/>
The most obviously useful annotation is @PreAuthorize which decides whether a method can actually be invoked or not. For example (from the"Contacts" sample application)
@PreAuthorize("hasRole('USER')") public void create(Contact contact);
which means that access will only be allowed for users with the role "ROLE_USER". Obviously the same thing could easily be achieved using a traditional configuration and a simple configuration attribute for the required role. But what about:
@PreAuthorize("hasPermission(#contact, 'admin')") public void deletePermission(Contact contact, Sid recipient, Permission permission);
Here we’re actually using a method argument as part of the expression to decide whether the current user has the "admin"permission for the given contact. The built-in hasPermission() expression is linked into the Spring Security ACL module through the application context, as we’llsee below. You can access any of the method arguments by name as expression variables.
There are a number of ways in which Spring Security can resolve the method arguments. Spring Security uses DefaultSecurityParameterNameDiscoverer to discover the parameter names. By default, the following options are tried for a method as a whole.
-
If Spring Security’s
@Pannotation is present on a single argument to the method, the value will be used. This is useful for interfaces compiled with a JDK prior to JDK 8 which do not contain any information about the parameter names. For example:import org.springframework.security.access.method.P; ... @PreAuthorize("#c.name == authentication.name") public void doSomething(@P("c") Contact contact);
Behind the scenes this use implemented using
AnnotationParameterNameDiscovererwhich can be customized to support the value attribute of any specified annotation. -
If Spring Data’s
@Paramannotation is present on at least one parameter for the method, the value will be used. This is useful for interfaces compiled with a JDK prior to JDK 8 which do not contain any information about the parameter names. For example:import org.springframework.data.repository.query.Param; ... @PreAuthorize("#n == authentication.name") Contact findContactByName(@Param("n") String name);
Behind the scenes this use implemented using
AnnotationParameterNameDiscovererwhich can be customized to support the value attribute of any specified annotation. - If JDK 8 was used to compile the source with the -parameters argument and Spring 4+ is being used, then the standard JDK reflection API is used to discover the parameter names. This works on both classes and interfaces.
- Last, if the code was compiled with the debug symbols, the parameter names will be discovered using the debug symbols. This will not work for interfaces since they do not have debug information about the parameter names. For interfaces,