Quoth ori@eigenstate.org:
> Quoth unobe@cpan.org:
[…]
> > I don't know if it's appropriate to mention in the man page that the
> > connection to OS X cannot be encrypted, so tunneling w/ssh is advised.
[…]
> It's worth mentioning that vnc auth in general is
> a joke, and some other mechanism, like sshnet,
> should be used for encryption.

Attached is a patch (git/import) that incorporates the modification to
vnc/auth.c enabling connections to Darwin hosts, as well as the
suggestions made to improve /sys/man/1/vnc.

Here is the inline version:

<snip>
From: Igor Böhm <igor@9lab.org>
Date: Sat, 25 Sep 2021 20:40:47 +0000
Subject: [PATCH] vncv: enable connecting to Darwin hosts


Tested on MacOS Catalina and Big Sur releases.

Update man page to highlight weak encryption of vnc, recommending to
tunnel via ssh (thanks unobe).

---
diff 235ef367d793db705b1b4ef20913c697eccd13a6 8abecdeed7f761e5a502bd1500ebbf2bc4962b43
--- a/sys/man/1/vnc	Sat Sep 25 18:57:58 2021
+++ b/sys/man/1/vnc	Sat Sep 25 22:40:47 2021
@@ -201,9 +201,12 @@
 If the remote frame buffer is larger than the local screen,
 only the upper left corner can be accessed.
 .PP
+.I Vncs
+and
+.I vncv
+encryption is not secure.  It's advisable to tunnel through
+ssh or some other secure protocol.
+.PP
 .I Vncv
 does no verification of the TLS certificate presented
 by the server.
-.PP
-.I Vncv
-supports only version 3.3 of the RFB protocol.
--- a/sys/src/cmd/vnc/auth.c	Sat Sep 25 18:57:58 2021
+++ b/sys/src/cmd/vnc/auth.c	Sat Sep 25 22:40:47 2021
@@ -33,6 +33,8 @@
 		v->vers = 37;
 	else if(strncmp(msg, "RFB 003.008\n", VerLen) == 0)
 		v->vers = 38;
+	else if(strncmp(msg, "RFB 003.889\n", VerLen) == 0)
+		v->vers = 38;  /* Darwin */
 	else /* RFC6143: Any other should be treated as 3.3. */
 		v->vers = 33;
 
<snap>

Cheers,
Igor