CSRF token per request in spring security

Question

How to implement csrf per request in spring security 3.2.Currently it is handled per session .This is a must requirement

Please post the changes that needs to be performed.

in securitycontext.xml

  <http>
    <csrf />
    </http>

is given and application is working with token per session

Answer 1

You can change the default implementation of CsrfTokenRepository by providing your own implementation of this interface and configure it like:

<http>
    <csrf token-repository-ref="myRequestCsrfTokenRepository"/>
</http>
<b:bean id="myRequestCsrfTokenRepository"
        class="com.company.security.RequestCsrfTokenRepository"/>

But... although you wrote that this is a must requirement, you should really rethink it again. I would even advice to try convincing the other end that this change could bring more security to the app users but can also bring a lot of inconveniences, sometimes strange behaviors and in general decrease the usability and user experience. Eg see Different csrf token per request in Spring security

Answer 2

I have implemented a custom csrf token repository which generates a new token for every http POST/DELETE req. I don't think token should be renewed for http GET, and if you look into source code of spring CsrfFilter class, it has a inner class DefaultRequiresCsrfFilter, which pass token checking for GET method.

The custom csrf token repository needs to implement interface CsrfTokenRepository. Actually I have reuse most of code of HttpSessionCsrfTokenRepository, which is spring default. The function that needs custom implementation is loadToken()

/*Customized loading token function, which invalidate the CSRF token once it is consumed. A new token is generated on next http req.*/

    public CsrfToken loadToken(HttpServletRequest request) {
        HttpSession session = request.getSession(false);
        CsrfToken token = session == null ? null : (CsrfToken)session.getAttribute(this.sessionAttributeName);
        if (/*HERE http request can be checked to see if it is a POST/DELETE */) {
            if (session != null) {
                //Remove the old token from session, and new token will be generated for next req 
                session.removeAttribute(DEFAULT_CSRF_TOKEN_ATTR_NAME);
            }
        }
        return token;
    }

And to get custom csrf token repository loaded, it needs to be configured in security.xml, as described in answers above.