From b5a868bbcd408c0c3f3c22e4bc0a128df34babc9 Mon Sep 17 00:00:00 2001
From: Simon Ser <contact@emersion.fr>
Date: Fri, 19 Nov 2021 18:55:07 +0100
Subject: [PATCH] Abort SASL if in-progress while completing registration

Implements the following recommendation from the spec:

> If the client completes registration (with CAP END, NICK, USER and any other
> necessary messages) while the SASL authentication is still in progress, the
> server SHOULD abort it and send a 906 numeric, then register the client
> without authentication.
---
 downstream.go | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/downstream.go b/downstream.go
index f60dbc9..3524493 100644
--- a/downstream.go
+++ b/downstream.go
@@ -1110,6 +1110,15 @@ func (dc *downstreamConn) register(ctx context.Context) error {
 		return fmt.Errorf("tried to register twice")
 	}
 
+	if dc.saslServer != nil {
+		dc.saslServer = nil
+		dc.SendMessage(&irc.Message{
+			Prefix:  dc.srv.prefix(),
+			Command: irc.ERR_SASLABORTED,
+			Params:  []string{"*", "SASL authentication aborted"},
+		})
+	}
+
 	password := dc.password
 	dc.password = ""
 	if dc.user == nil {