From f9817cf817ed8337bfa55e30e7d32d5d1a74c2c7 Mon Sep 17 00:00:00 2001
From: Kévin Le Gouguec <kevin.legouguec@gmail.com>
Date: Fri, 9 Oct 2020 23:18:13 +0200
Subject: Note down ERC itch

---
 itches/emacs/tracker.org | 48 ++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 48 insertions(+)

diff --git a/itches/emacs/tracker.org b/itches/emacs/tracker.org
index ba198b0..bec0311 100644
--- a/itches/emacs/tracker.org
+++ b/itches/emacs/tracker.org
@@ -154,6 +154,54 @@ Fixed by Dmitry.
 :TestAdded:      t
 :END:
 My commit message ran afoul of debbugs.el's =M-m= again.
+*** ERC
+**** TODO Support SASL authentication
+Got bitten by this when trying to connect to irc.freenode.net from
+=alyon-654-1-454-60.w109-213.abo.wanadoo.fr=:
+#+begin_quote
+ERROR from irc.freenode.net: Closing Link:
+alyon-654-1-454-60.w109-213.abo.wanadoo.fr (SASL access only)
+#+end_quote
+
+This was requested in [[bug:29108]].  Lars closed this report because
+while there is a third-party package to implement the feature, its
+author did not respond when prompted for copyright assignment.
+
+I did not have the patience to look at the package; instead I went
+straight to [[https://ircv3.net/specs/extensions/sasl-3.1][the description of SASL on ircv3.net]] and the [[https://tools.ietf.org/html/rfc4616#section-2][RFC for the
+=PLAIN= mechanism]], and cobbled this silly patch:
+
+#+begin_src diff
+diff --git a/lisp/erc/erc.el b/lisp/erc/erc.el
+index 1d5506e281..0da677ac18 100644
+--- a/lisp/erc/erc.el
++++ b/lisp/erc/erc.el
+@@ -6052,7 +6052,17 @@ erc-login
+                    erc-session-server
+                    erc-session-user-full-name))
+   (if erc-session-password
+-      (erc-server-send (format "PASS %s" erc-session-password))
++      (progn
++        (erc-server-send "CAP REQ :sasl")
++        (erc-server-send "AUTHENTICATE PLAIN")
++        (erc-server-send
++         (concat "AUTHENTICATE " (base64-encode-string
++                                  (string-join (list
++                                                (user-login-name)
++                                                (erc-current-nick)
++                                                erc-session-password)
++                                               "\0"))))
++        (erc-server-send "CAP END"))
+     (message "Logging in without password"))
+   (erc-server-send (format "NICK %s" (erc-current-nick)))
+   (erc-server-send
+#+end_src
+
+AFAICT this is enough to get me authenticated on Freenode.  It looks
+like it's not too hard to implement?
+
+Ideally Emacs's builtin =sasl.el= should be reused; that would let ERC
+support better SASL mechanisms than =PLAIN=.
 *** Gnus
 **** DONE [[bug:40520]] Prevent duplicate thread titles
 :PROPERTIES:
-- 
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