SF_10.1, SF_10.2, SF_11.0, SF_11.1, SF_11.2, SF_12.0, SF_12.1, SF_12.2, SF_13.0, SF_13.1, SF_13.2, SF_13.3, SF_14.0, SF_14.1, SF_14.2, SF_14.3 - https://docs.sitefinity.com/for-developers-check-and-demand-permissions

GetActivePermissions.cs

using System.Linq;
using Telerik.Sitefinity.Modules.Blogs;
using Telerik.Sitefinity.Security;
using Telerik.Sitefinity.Security.Model;

namespace SitefinityWebApp
{
    public class GetActivePermissions
    {
        public IQueryable GetActivePermissionsMethod()
        {
            BlogsManager blogsManager = BlogsManager.GetManager();

            ISecuredObject securedObject = blogsManager.GetSecurityRoot(false);

            IQueryable<Telerik.Sitefinity.Security.Model.Permission> permissions = securedObject.GetActivePermissions();

            return permissions;
        }
    }
}