On Windows, configuring a named pipe server with pipe_mode will force ServerOptions::reject_remote_clients as false.

This drops any intended explicit configuration for the reject_remote_clients that may have been set as true previously.

The default setting of reject_remote_clients is normally true meaning the default is also overridden as false.

Workarounds

Ensure that pipe_mode is set first after initializing a ServerOptions. For example:

let mut opts = ServerOptions::new();
opts.pipe_mode(PipeMode::Message);
opts.reject_remote_clients(true);

If a close_notify alert is received during a handshake, complete_io does not terminate.

Callers which do not call complete_io are not affected.

rustls-tokio and rustls-ffi do not call complete_io and are not affected.

rustls::Stream and rustls::StreamOwned types use complete_io and are affected.

In 0.11.0, we overhauled the server-side Endpoint implementation to enable more careful handling of incoming connection attempts. However, some of the code paths that cleaned up state after connection attempts were processed confused the initial destination connection ID with the destination connection ID of a substantial package. This resulted in the internal Endpoint state becoming inconsistent, which could then lead to a panic.

https://github.com/quinn-rs/quinn/commit/e01609ccd8738bd438d86fa7185a0f85598cb58f

Thanks to @finbear for reporting and investingating, and to @BiagoFesta for coordinating.