[jsr-314-open-mirror] [jsr-314-open] [Spec-869-Specify CSRF Solution] PROPOSAL(s)

[Alexander Smirnov]

The #2 approach is already here, it's JSF view state field. It would be
make even stronger by some random string added to its value, but that
doesn't require any change in spec; the format of state field is up to
implementation.
The #1 is also available as custom view parameter, but we can make it
more convinient as implicit view parameter and  metadata control
included in all ( or selected ) navigation links and views. It would
leverage already existing JSF 2.0 features. As well as view parameters
processed in the separate ExternalContext method, they are portlet-safe.



On 09/21/2010 10:15 AM, Roger Kitain wrote:
> 
> There are two proposals for enhancing CSRF attacks in JSF.  We need to
> pick one.
> 
> Proposal 1: Form Action URL Approach (Approach provided by Kito Mann)
> 
> This approach does the following:      - Token is generated on the
> server consisting (minimally) of a randomly generated "secret key
>      (stored in session).
>    - ViewHandler.getActionURL method must include the token parameter
>      named "javax.faces.Token", and whose value is the token value.
>    - At render time this token will be included in Form's action URL -
> and it will be
>      posted back to the server.
>    - Restore View Phase processing compares the incoming token request
> parameter value
>      with the token value generated from the secret key in the session.
> 
> Spec Document Modifications:
> 
> Section 7.5.1:
> 
> getActionURL:
> 
> "The URL must contain the parameter constant defined by
> ResponseStateManager.VIEW_TOKEN_PARAM
> The value of this parameter must be a cryptographically produced value
> minimally consisting
> of a "secret key". The "secret key" is a random generated value that was
> stored in the session
> (preferably around session creation time).  Implementations may also
> choose to combine other
> values with the secret key to produce a more complex token."
> 
> Section 2.2.1
> 
>  "Verify the "javax.faces.Token" request parameter value is the same as
> the token value generated
>    from the "secret key" stored in the session.  If the values do not
> match, throw a meaningful
>    exception."
> 
> 
> Proposal 2: Form Hidden Field Approach
> 
> This approach is similar to Approach 1, except a Form hidden field
> "javax.faces.Token"
> is used instead of appending to the Form's Action URL.
> 
> Spec Document Modifications:
> 
> Standard RenderKit Docs
> 
> - Form Rendering
> 
> "Render a hidden field named "javax.faces.Token" using the
> ResponseStateManager.VIEW_TOKEN_PARAM
>  constant.  The value of this hidden field is a cryptographically
> produced value that must at least
>  consist of a "secret key".  The "secret key" is a random generated
> value that was stored in the
>  session (preferably around session creation time).  Implementations may
> also choose to combine
>  other values with the secret key to produce a more complex token."
> 
> Specification Document
> 
> Section 2.2.1
>   "Verify the "javax.faces.Token" request parameter value is the same as
> the token value generated
>    from the "secret key" stored in the session.  If the values do not
> match, throw a FacesException.
> 
> 
> For both approaches see:
> 
> 
> [1]
> https://javaserverfaces-spec-public.dev.java.net/issues/show_bug.cgi?id=869
> 
> Look at the two latest change bundles attached to the issue.
> 
> Please review by COB Friday as we have no time left for 2.1.
> 
> Kudos to Kito Mann for helping out with the implementation.
> 
> -roger