Spring Security问题

操作方法

• 01

  一. General Questions 1. Will Spring Security take care of all my application security requirements? 2. Why not just use web.xml security? 3. What Java and Spring Framework versions are required? 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? 1.1. Will Spring Security take care of all my application security requirements? Spring Security provides you with a very flexible framework for your authentication and authorization requirements, but there are many other considerations for building a secure application that are outside its scope. Web applications are vulnerable to all kinds of attacks which you should be familiar with, preferably before you start development so you can design and code with them in mind from the beginning. Check out thehttp://www.owasp.org/[OWASP web site] for information on the major issues facing web application developers and the countermeasures you can use against them. 1.2. Why not just use web.xml security? Let’s assume you’re developing an enterprise application based on Spring. There are four security concerns you typically need to address: authentication, web request security, service layer security (i.e. your methods that implement business logic), and domain object instance security (i.e. different domain objects have different permissions). With these typical requirements in mind: Authentication: The servlet specification provides an approach to authentication. However, you will need to configure the container to perform authentication which typically requires editing of container-specific "realm" settings. This makes a non-portable configuration, and if you need to write an actual Java class to implement the container’s authentication interface, it becomes even more non-portable. With Spring Security you achieve complete portability - right down to the WAR level. Also, Spring Security offers a choice of production-proven authentication providers and mechanisms, meaning you can switch your authentication approaches at deployment time. This is particularly valuable for software vendors writing products that need to work in an unknown target environment. Web request security: The servlet specification provides an approach to secure your request URIs. However, these URIs can only be expressed in the servlet specification’s own limited URI path format. Spring Security provides a far more comprehensive approach. For instance, you can use Ant paths or regular expressions, you can consider parts of the URI other than simply the requested page (e.g. you can consider HTTP GET parameters) and you can implement your own runtime source of configuration data. This means your web request security can be dynamically changed during the actual execution of your webapp. Service layer and domain object security: The absence of support in the servlet specification for services layer security or domain object instance security represent serious limitations for multi-tiered applications. Typically developers either ignore these requirements, or implement security logic within their MVC controller code (or even worse, inside the views). There are serious disadvantages with this approach: a.Separation of concerns: Authorization is a crosscutting concern and should be implemented as such. MVC controllers or views implementing authorization code makes it more difficult to test both the controller and authorization logic, more difficult to debug, and will often lead to code duplication. b.Support for rich clients and web services: If an additional client type must ultimately be supported, any authorization code embedded within the web layer is non-reusable. It should be considered that Spring remoting exporters only export service layer beans (not MVC controllers). As such authorization logic needs to be located in the services layer to support a multitude of client types. c.Layering issues: An MVC controller or view is simply the incorrect architectural layer to implement authorization decisions concerning services layer methods or domain object instances. Whilst the Principal may be passed to the services layer to enable it to make the authorization decision, doing so would introduce an additional argument on every services layer method. A more elegant approach is to use a ThreadLocal to hold the Principal, although this would likely increase development time to a point where it would become more economical (on a cost-benefit basis) to simply use a dedicated security framework. d.Authorisation code quality: It is often said of web frameworks that they "make it easier to do the right things, and harder to do the wrong things". Security frameworks are the same, because they are designed in an abstract manner for a wide range of purposes. Writing your own authorization code from scratch does not provide the "design check" a framework would offer, and in-house authorization code will typically lack the improvements that emerge from widespread deployment, peer review and new versions. For simple applications, servlet specification security may just be enough. Although when considered within the context of web container portability, configuration requirements, limited web request security flexibility, and non-existent services layer and domain object instance security, it becomes clear why developers often look to alternative solutions. 1.3. What Java and Spring Framework versions are required? Spring Security 3.0 and 3.1 require at least JDK 1.5 and also require Spring 3.0.3 as a minimum. Ideally you should be using the latest release versions to avoid problems. Spring Security 2.0.x requires a minimum JDK version of 1.4 and is built against Spring 2.0.x. It should also be compatible with applications using Spring 2.5.x. 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? Or subsititute an alternative complex scenario… Realistically, you need an understanding of the technolgies you are intending to use before you can successfully build applications with them. Security is complicated. Setting up a simple configuration using a login form and some hard-coded users using Spring Security’s namespace is reasonably straightforward. Moving to using a backed JDBC database is also easy enough. But if you try and jump straight to a complicated deployment scenario like this you will almost certainly be frustrated. There is a big jump in the learning curve required to set up systems like CAS, configure LDAP servers and install SSL certificates properly. So you need to take things one step at a time. From a Spring Security perspective, the first thing you should do is follow the "Getting Started" guide on the web site. This will take you through a series of steps to get up and running and get some idea of how the framework operates. If you are using other technologies which you aren’t familiar with then you should do some research and try to make sure you can use them in isolation before combining them in a complex system.