ksmbd: close accepted socket when per-IP limit rejects connection

ksmbd: close accepted socket when per-IP limit rejects connection

commit 98a5fd31cbf72d46bf18e50b3ab0ce86d5f319a9 upstream.

When the per-IP connection limit is exceeded in ksmbd_kthread_fn(),
the code sets ret = -EAGAIN and continues the accept loop without
closing the just-accepted socket. That leaks one socket per rejected
attempt from a single IP and enables a trivial remote DoS.

Release client_sk before continuing.

This bug was found with ZeroPath.

Cc: stable@vger.kernel.org
Signed-off-by: Joshua Rogers <linux@joshua.hu>
Acked-by: Namjae Jeon <linkinjeon@kernel.org>
Signed-off-by: Steve French <stfrench@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>