From mboxrd@z Thu Jan  1 00:00:00 1970
Message-ID: <37dc31191ad95043011ccf18788b8dcd@plan9.bell-labs.com>
From: David Presotto <presotto@closedmind.org>
To: miller@hamnavoe.demon.co.uk, 9fans@cse.psu.edu
Subject: Re: [9fans] factotum apop protocol is incorrect
MIME-Version: 1.0
Content-Type: multipart/mixed;
	boundary="upas-llhganjhqwvqeiiqkafsbwyucb"
Date: Fri, 12 Dec 2003 14:59:46 -0500
Topicbox-Message-UUID: a0c6b810-eacc-11e9-9e20-41e7f4b1d025

This is a multi-part message in MIME format.
--upas-llhganjhqwvqeiiqkafsbwyucb
Content-Disposition: inline
Content-Type: text/plain; charset="US-ASCII"
Content-Transfer-Encoding: 7bit

I really dinna want to change %H.  The logical thing there would be to
have a %h and a %H but little 'h' is already taken as a flag.

I'll just fix apop with your suggestion.
--upas-llhganjhqwvqeiiqkafsbwyucb
Content-Type: message/rfc822
Content-Disposition: inline

Received: from plan9.cs.bell-labs.com ([135.104.9.2]) by plan9; Fri Dec 12 14:49:34 EST 2003
Received: from mail.cse.psu.edu ([130.203.4.6]) by plan9; Fri Dec 12 14:49:32 EST 2003
Received: by mail.cse.psu.edu (CSE Mail Server, from userid 60001)
	id 4BB7519ABA; Fri, 12 Dec 2003 14:49:27 -0500 (EST)
Received: from psuvax1.cse.psu.edu (psuvax1.cse.psu.edu [130.203.20.6])
	by mail.cse.psu.edu (CSE Mail Server) with ESMTP
	id ACB1A19BA9; Fri, 12 Dec 2003 14:49:08 -0500 (EST)
X-Original-To: 9fans@cse.psu.edu
Delivered-To: 9fans@cse.psu.edu
Received: by mail.cse.psu.edu (CSE Mail Server, from userid 60001)
	id 5A1AD19AF8; Fri, 12 Dec 2003 14:48:11 -0500 (EST)
Received: from hamnavoe.gotadsl.co.uk (hamnavoe.gotadsl.co.uk [213.208.117.150])
	by mail.cse.psu.edu (CSE Mail Server) with ESMTP id EAE6319ABA
	for <9fans@cse.psu.edu>; Fri, 12 Dec 2003 14:47:58 -0500 (EST)
Message-ID: <b07c2ff1dcb618953620ac173286d274@hamnavoe.com>
To: 9fans@cse.psu.edu
From: Richard Miller <miller@hamnavoe.demon.co.uk>
MIME-Version: 1.0
Content-Type: text/plain; charset="US-ASCII"
Content-Transfer-Encoding: 7bit
Subject: [9fans] factotum apop protocol is incorrect
Sender: 9fans-admin@cse.psu.edu
Errors-To: 9fans-admin@cse.psu.edu
X-BeenThere: 9fans@cse.psu.edu
X-Mailman-Version: 2.0.11
Precedence: bulk
Reply-To: 9fans@cse.psu.edu
List-Id: Fans of the OS Plan 9 from Bell Labs <9fans.cse.psu.edu>
List-Archive: <https://lists.cse.psu.edu/archives/9fans/>
Date: Fri, 12 Dec 2003 19:47:35 0000
X-Spam-Status: No, hits=0.6 required=5.0
	tests=INVALID_DATE
	version=2.55
X-Spam-Level:
X-Spam-Checker-Version: SpamAssassin 2.55 (1.174.2.19-2003-05-19-exp)

RFC1939 introduces the 'APOP name digest' command for
challenge-response authentication to a POP3 mail server, and says:
"The digest parameter ...  is sent in hexadecimal format, using
lower-case ASCII characters."

Factotum's proto=apop implementation encodes the digest as
upper-case hexadecimal.

Probably most POP3 servers can handle both, but I've just hit
an unforgiving one.

Possible fixes:

In /sys/src/cmd/auth/factotum/apop.c, replace
		sprint(s->resp, "%.*H", MD5dlen, digest);
with something like
		for(i=0; i<MD5dlen; i++)
			sprint(&s->resp[2*i], "%.2x", digest[i]);

or in /sys/src/libc/port/u16.c, replace
	static char t16e[] = "0123456789ABCDEF";
with
	static char t16e[] = "0123456789abcdef";

The latter has a more widespread effect, but it arguably makes the %H
format conform to its documentation.  The man page for print(2) makes
a distinction between "hexadecimal" and "upper case hexadecimal" for
%x and %X respectively.  enc16(2) just says %H means "base 16 (i.e.
hexadecimal)", so one might expect it to be lower case.

-- Richard Miller

--upas-llhganjhqwvqeiiqkafsbwyucb--