GHSA-76R6-X97P-67VR Russh: SSH identification parsing accepted non-canonical client banners and did not bound pre-banner input

Summary russh did not enforce the SSH identification-string rules as deliberately as OpenSSH. In particular, the server-side identification reader used the same permissive path as the client, allowing pre-banner lines from clients, and the reader did not enforce a bounded number of pre-banner...