Skip to main content

WCF Hosted on a Network Share

Whilst working on a proof of concept WCF service I ran into an interesting security “zone” issue which caused me a few headaches for an afternoon.  I was moving some code out of a prototype WinForm application into a WCF service to prove and demonstrate the next phase of the infrastructure.  The functionality in question reference some custom ‘C’ libraries which had already been proven to run when referenced locally within the Windows application.  However moving the same the code and therefore the reference to the ‘C’ libraries into a WCF service resulted in most calls to the library throwing a “Security Exception”.  Stepping through the debugger, the issue was clear enough, calling “unsafe” code requires Full Trust but even though everything was running locally the WCF service was showing as “Internet” zone and triggering the security exception.   This had me confused for quite a while, I wasn’t hosting the WCF service within IIS (see previous post, no admin rights!), so my only option was the WCFHost application.  No searches on Google could find anything related, everything seemed to indicate that in this situation the WCF application should run in the same security zone/context as the calling application - which I had verified was running in Full Trust mode.

My final attempt before calling it a day and going home was to try and register the DLL within the GAC and hope that solved the trust issue.  It was only when clicking on “Add an assembly to the assembly cache” I noticed that only two drive letters were listed.  The solution I was developing was located on the mapped network drive that didn’t appear in the list.  As a quick test I moved the solution onto one of the non mapped drives, recompiled the application and tried again.  This time everything worked – developing on a mapped drive had resulted in WCFHost dropping the security level that the code was running under!

del.icio.us Tags:

Comments

Popular posts from this blog

Why do my Android Notification only appear in the status bar?

I'm definitely getting back into Android development, I'm remembering that feeling of 'Surely this should be easier than this!'. All I wanted to do was to schedule a local notification which behaved similar to a push notification pop-up. That is, as well as showing the small icon in the status bar I wanted it to pop up on screen to notify the end user. All seems fairly easily, I found this code for how to schedule a notification. That all worked perfectly, apart from the notification would only appear in the status bar. Searching around I found loads of different answers / solutions, mostly all saying the same thing:It only worked if you used 'NotificationCompat.Builder' in place of 'Notification.Builder', orYou had to set the priority to 'NotificationCompat.PRIORITY_HIGH'As usually happens, none of these solutions worked for me until I added in the missing piece of the jigsaw:- '.setDefaults(Notification.DEFAULT_ALL)'. For me this…

Do "Task Hours" add anything in Scrum (Agile)?

What do task hours add to the overall process in scrum?This was a question that has arisen from all team members in both instances that I've helped teams switch over to scrum. The benefits of artifacts like the comparative story point estimation, the 2 week sprints, stand-ups and the end of sprint demo have been self evident to the team, but as one I think every team member has expressed dismay when it comes to task planning and estimating each task in hours. Left unchecked there is a natural tendency for people to actually begin to dread the start of each sprint purely due to the task planning session.In my current role we've been lucky to investigate this further as a team.The team sat down to discuss the problems it was experiencing with estimating tasks in hours and the following common themes appeared:It is hard: Maybe it shouldn't be, but time estimation is hard! Story points are comparative and abstracted making them easier to determine, but time estimate is gen…

IPhone hangs when running from XCode

I've had this happen a couple of times now and the first time was a little worrying that I'd bricked my iPhone. Basically I was running an application on my phone via XCode and when rebuilding an updated version it failed with a "busy" error message. Stopping XCode and unconnecting my phone had no effect, the phone was stuck displaying the loading screen of the application and wouldn't respond to any key commands. To fix you have to hard reboot, holding the power and home button until the phone reboots - doesn't lose any of the data you have on your phone (a concern the first time I did it).