Andy, I agree that filtering the method response is a fascinating area. The only problem I have always found on filtering a method response is that it doesn't scale properly when performance is an issue. I'm particularly thinking on Collections here, where the full collection check for permissions would degrade performance on big enough collections.
Maybe providing "intelligent" collections and Iterators that perform the security check when accessed could be a wiser approach for that area (like hibernate for lazy load modification). That would imply that a response from a method would be a proxy on the original object that enforces all the security restrictions specified. -----Mensaje original----- De: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] En nombre de Andy Depue Enviado el: viernes, 31 de diciembre de 2004 0:26 Para: acegisecurity-developer@lists.sourceforge.net Asunto: Re: [Acegisecurity-developer] MSc Thesis on middle tier security The new model object filtering is a fascinating area in my mind. One thing we've implemented (before Acegi had its own filtering) is the ability to filter down to the property level on an object. In other words, you can secure a specific property and if someone doesn't have clearance then the property will be cleared. This introduces all sorts of interesting problems in some scenarios. For example, in our case the value objects passed back and forth between clients and server side services double as our Hibernate data object model. In other words, we don't have separate value objects but instead use a single data object model for both data access and service invocation. This gets quite tricky when you combine it with property level filtering. Imagine a service method that returns a model object with several properties filtered out. The user then makes some changes to the object and sends it back in another service call to be updated. What the user sends back to the server is a partial object in that some of the properties are blank since they were secured from the client to begin with. If you persisted the object as-is, then Hibernate would blindly write those cleared property values back to the DB - very bad. Oh, and don't forget that some properties could be secured for a particular client so that they are read-only or even write-only. And don't forget to throw a security exception if the client tries to pass a value in a non-writeable field. And then there's recursive data structures to contend with... property values that are themselves collections of securable objects... and if you filtered a collection of securable objects from a property, and the client returns that object to the server to be updated, how do you determine if the client legitimately removed an object from the collection, or if the object was filtered due to security? You wouldn't want to have hibernate persist the collection as-is, or it would remove from the DB objects that were only filtered for security reasons. Fun stuff, eh? - Andy On Thursday 30 December 2004 01:49 pm, Vladimir Horev wrote: > Hello list! > > I'm planning to write a MSc thesis on the subject of business tier > security. My idea was to take part of some open source project (acegi) > and develop some component that I could use in my thesis. Could you > recommend me something on that? > > regards, Vladimir > > > ------------------------------------------------------- > The SF.Net email is sponsored by: Beat the post-holiday blues > Get a FREE limited edition SourceForge.net t-shirt from ThinkGeek. > It's fun and FREE -- well, almost....http://www.thinkgeek.com/sfshirt > _______________________________________________ > Home: http://acegisecurity.sourceforge.net > Acegisecurity-developer mailing list > Acegisecurity-developer@lists.sourceforge.net > https://lists.sourceforge.net/lists/listinfo/acegisecurity-developer ------------------------------------------------------- The SF.Net email is sponsored by: Beat the post-holiday blues Get a FREE limited edition SourceForge.net t-shirt from ThinkGeek. It's fun and FREE -- well, almost....http://www.thinkgeek.com/sfshirt _______________________________________________ Home: http://acegisecurity.sourceforge.net Acegisecurity-developer mailing list Acegisecurity-developer@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/acegisecurity-developer -- No virus found in this incoming message. Checked by AVG Anti-Virus. Version: 7.0.296 / Virus Database: 265.6.7 - Release Date: 30/12/2004
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