What you are describing is a very UX pattern, which is a policy editor. Generally, this entails selecting and editing a policy, and visualizing/editing the scope of the policy.
Usually this results in an interface similar to what you sketched out, but with some adjustments:
For the left hand column, it's unclear whether the checkboxes are controls or just indicators. If they are controls, it's awkward to have a "control within a control". If it's a visualization, consider removing the box and just displaying the check mark.
Confusing use of the term 'Edit'. You have an edit button which allows admins to edit permissions. You also use 'Edit' to describe whether a permission allows a user to edit a page. Consider migrating this second term to something like 'can edit'.
You obviously have a lot of potential pages in the right hand column (hence the more... button). Policy editors often show just the pages which the user has permissions for. This saves space, and makes both the flow and presentation simpler. If you need to be able to add a page to the list (for a given permission), then place an 'Add page...' button.
Lastly, it would be helpful to have some visual connection between the left and right columns, to indicate that the left relates to the right. For example, a triangular indicator between the columns.
Aside from these critiques, what you've laid out is a pretty common solution to a pretty common problem. If you're looking for live examples, you can look at the Windows or Mac security policy editor, Google Apps permissions interface, Amazon Web Services security policy or load balancer editor, etc.
Hope that helps