From mboxrd@z Thu Jan 1 00:00:00 1970 X-Msuck: nntp://news.gmane.io/gmane.emacs.gnus.general/67540 Path: news.gmane.org!not-for-mail From: Matthias Andree Newsgroups: gmane.emacs.gnus.general Subject: Re: Bug#499774: starttls is a joke Date: Tue, 07 Oct 2008 22:41:25 +0200 Message-ID: References: <871vzca7gp.fsf@natisbad.org> <87y71kpmq7.fsf@bubble.risko.hu> <87od2g31hf.fsf@natisbad.org> <87tzc8upgf.fsf@marauder.physik.uni-ulm.de> NNTP-Posting-Host: lo.gmane.org Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii X-Trace: ger.gmane.org 1223412189 16442 80.91.229.12 (7 Oct 2008 20:43:09 GMT) X-Complaints-To: usenet@ger.gmane.org NNTP-Posting-Date: Tue, 7 Oct 2008 20:43:09 +0000 (UTC) Cc: Daiki Ueno , Simon Josefsson , 499774@bugs.debian.org, RISKO Gergely , ding@gnus.org To: Arnaud Ebalard Original-X-From: ding-owner+M15991@lists.math.uh.edu Tue Oct 07 22:44:06 2008 Return-path: Envelope-to: ding-account@gmane.org Original-Received: from util0.math.uh.edu ([129.7.128.18]) by lo.gmane.org with esmtp (Exim 4.50) id 1KnJPa-0001WC-0S for ding-account@gmane.org; Tue, 07 Oct 2008 22:44:06 +0200 Original-Received: from localhost ([127.0.0.1] helo=lists.math.uh.edu) by util0.math.uh.edu with smtp (Exim 4.63) (envelope-from ) id 1KnJOG-00064b-2p; Tue, 07 Oct 2008 15:42:44 -0500 Original-Received: from mx1.math.uh.edu ([129.7.128.32]) by util0.math.uh.edu with esmtps (TLSv1:AES256-SHA:256) (Exim 4.63) (envelope-from ) id 1KnJNd-00063z-CA for ding@lists.math.uh.edu; Tue, 07 Oct 2008 15:42:05 -0500 Original-Received: from quimby.gnus.org ([80.91.231.51]) by mx1.math.uh.edu with esmtp (Exim 4.69) (envelope-from ) id 1KnJNZ-0006Om-8t for ding@lists.math.uh.edu; Tue, 07 Oct 2008 15:42:05 -0500 Original-Received: from mail.gmx.net ([213.165.64.20]) by quimby.gnus.org with smtp (Exim 3.36 #1 (Debian)) id 1KnJNe-0007Nj-00 for ; Tue, 07 Oct 2008 22:42:06 +0200 Original-Received: (qmail invoked by alias); 07 Oct 2008 20:41:28 -0000 Original-Received: from g227125196.adsl.alicedsl.de (EHLO m2a2.dyndns.org) [92.227.125.196] by mail.gmx.net (mp053) with SMTP; 07 Oct 2008 22:41:28 +0200 X-Authenticated: #428038 X-Provags-ID: V01U2FsdGVkX19FzXZpt7lFvYYkzyyEIkeEcWfacEFmgCYcpQhCmp fQMtqNNj+1YDES Original-Received: from localhost (localhost [127.0.0.1]) by merlin.emma.line.org (Postfix) with ESMTP id B0435200338; Tue, 7 Oct 2008 22:41:25 +0200 (CEST) X-Virus-Scanned: amavisd-new at emma.line.org Original-Received: from m2a2.dyndns.org ([127.0.0.1]) by localhost (m2a2.dyndns.org [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id tjL+tJg8Xdqg; Tue, 7 Oct 2008 22:41:25 +0200 (CEST) Original-Received: by merlin.emma.line.org (Postfix, from userid 500) id 4EDFB2005AE; Tue, 7 Oct 2008 22:41:25 +0200 (CEST) In-Reply-To: <87tzc8upgf.fsf@marauder.physik.uni-ulm.de> (Reiner Steib's message of "Mon, 22 Sep 2008 18:15:28 +0200") User-Agent: Gnus/5.110011 (No Gnus v0.11) Emacs/22.2 (gnu/linux) X-PGP-Key: http://home.pages.de/~mandree/keys/GPGKEY.asc X-Y-GMX-Trusted: 0 X-FuHaFi: 0.57 X-Spam-Score: -2.6 (--) List-ID: Precedence: bulk Xref: news.gmane.org gmane.emacs.gnus.general:67540 Archived-At: Reiner Steib writes: >> Then, someone should correct the code to support passing trust anchors, >> allow passing the verify value, and document capabilities and >> limitations. > > Gnus currently uses starttls if starttls and gnutls-cli are available > for backward compatibility. > > Would it make sense to prefer gnutls-cli and warn when using starttls > (if gnutls-cli is not installed)? It would make sense to fix the tools first, and stop using them in unsafe ways. I recently found on Cygwin, when setting up Emacs+Gnus, that gnutls-cli (2.4.2 IIRC) has some subtle "accept b0rked cert chain" behaviour: it would happily accept any garbage^Wuntrusted certificate chain without notice -- when I'm not using "--x509cafile FOO" on the command line. This isn't documented anywhere (manual, manpage, --help), I found this out through systematic testing. I find this most disturbing, since if I don't provide a set of trusted X.509 CA certs, I trust nobody (rather than everybody as gnutls-cli does)... gnutls-cli should bail out if it has no trusted root certificates, rather than silently trust everyone. Go figure - there's a difference between giving "--x509cafile /dev/null" and not giving this option at all. :-( While I'm at it, from the end user's perspective, I find it very hard to figure what options I need for a proper configuration that doesn't use b0rked protocols such as SSLv2, that uses proper X.509 certificate validation to detect MITM attacks. Few applications except Firefox 3 get that right, and I couldn't tell one off-hand. I think that EVERY tool that has a remotely security-related context should default to bulletproof mode and require that the user relaxes every test explicitly. Yes, I need to do homework here, fetchmail doesn't get this right either... compatibility and all that. So I'd say make Gnus default to gnutls-cli and change the sample configuration to include --x509cafile and add instructions to the defcustom blah self-documentation telling the user to cat(1) his trusted ROOT certificates (in PEM format) together to form this file. -- Matthias Andree