'Checks user access permissions for paths under aff4:/users.'

def _IsHomeDir(self, subject, token):

    h = CheckAccessHelper('IsHomeDir')
    h.Allow(('aff4:/users/%s' % token.username))
    h.Allow(('aff4:/users/%s/*' % token.username))
    try:
        return h.CheckAccess(subject, token)
    except access_control.UnauthorizedAccess:
        raise access_control.UnauthorizedAccess('User    can    only    access    their    home    directory.', subject=subject)
