Information exposure through Link header by guessing an allocated URI

NSS responds to unauthenticated and unauthorized GET requests to /foo/bar (that exists) by including the HTTP header:

Link: <bar.acl>; rel="acl", <bar.meta> rel="describedBy", <http://www.w3.org/ns/ldp#Resource>; rel="type"

For GET requests to non-existing resources eg. /foo/baz, the response doesn't include the HTTP Link header.

Thus, the security consideration: existence of a resource can potentially be known by guessing or anticipating an allocated URI.

There are use cases where the server may want to reveal the information in the Link header in the response. If the server doesn't make the distinction between intentionally revealing and unintentionally exposing, the server is encouraged to minimize information leaking. So, in the case here, it should be consistent by omitting the Link header for unauthenticated and unauthorized requests.

跟踪现有路径和缺失路径的 GET 请求处理及 Link header 生成。比较针对 /foo/bar 和 /foo/baz 的未认证请求与未授权请求；完成的标准是，对于这些被拒绝的请求，Link header 始终不存在，并且测试覆盖预期的信息披露行为。