Giving permission to a report
Permissions govern which task one can carry out. Permissions in SP are like roles in native mode reporting services. SharePoint has some 33 predefined permissions that can be bundled into a permission level.
The built-in security features of SharePoint Foundation 2010 can be used to grant access to Report Server items on SharePoint sites and libraries. Users already permitted to the sites and libraries can access these items unless their permissions are modified. But regarding the permissions for users added after SharePoint integration there are recommendations for granting permissions to securable items on the site such as libraries, documents, lists, and so on.
Users belong to SharePoint groups that you can create ...