[TLS] TLS1.3 clarification request

[Jeremy Harris <[e-mail]>]

Hi,

Could people please confirm a detail of TLS 1.3 session
close behaviour?  Specifically, are half-closes supported
in similar fashion to TCP half-closes - in that it is
legitimate for one end to issue a Close Notify alert
and for the other end to receive that alert but continue
to transmit data after such reception and before sending
its own Close Notify?

Further, is it reasonable for the above first end to
expect the above second end to continue processing and
sending data that would have been sent in the absence of
such a first Close Alert?


I ask because of the observed actions of Google MTA servers.
When using a TLS1.3 connection, after STARTTLS on an ESMTP
connection with PIPELINING and CHUNKING - if the smtp client
pipelines a full set of MAIL, RCPT, BDAT nnnn LAST, QUIT
*and* follows those with a TLS Close Notify then the Google
server issues an immediate TCP FIN.  It does this without
sending any SMTP responses (even for the MAIL command)
and it does not send a TLS Alert of any kind.

If the full ESMTP sequence give is sent without the TLS
Close Notify, then SMTP responses are transmitted by the
SMTP server as expected.
-- 
Cheers,
   Jeremy

PS: I am aware that TLS1.2 does not support half-closes.