GNU bug report logs - #13374
24.?; open-gnutls-stream insecurity

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From: help-debbugs <at> gnu.org (GNU bug Tracking System)
To: Ted Zlatanov <tzz <at> lifelogs.com>
Cc: tracker <at> debbugs.gnu.org
Subject: bug#13877: closed (24.3; gnutls.el: Enable Certificate Checks)
Date: Wed, 18 Dec 2013 22:50:03 +0000

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Your message dated Wed, 18 Dec 2013 17:50:39 -0500
with message-id <87r499ixj4.fsf <at> flea.lifelogs.com>
and subject line Re: bug#13374: 24.?; open-gnutls-stream insecurity
has caused the debbugs.gnu.org bug report #13374,
regarding 24.3; gnutls.el: Enable Certificate Checks
to be marked as done.

(If you believe you have received this mail in error, please contact
help-debbugs <at> gnu.org.)


-- 
13374: http://debbugs.gnu.org/cgi/bugreport.cgi?bug=13374
GNU Bug Tracking System
Contact help-debbugs <at> gnu.org with problems

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From: Moritz Ulrich <moritz <at> tarn-vedra.de>
To: bug-gnu-emacs <at> gnu.org
Subject: 24.3; gnutls.el: Enable Certificate Checks
Date: Tue, 05 Mar 2013 11:40:09 +0100

Currently, gnutls.el doesn't check certificate signatures when used via
`open-network-stream' with :type 'tls or `open-gnutls-stream'.

This is caused by the following code from `open-gnutls-stream'
(gnutls.el:110):

--8<---------------cut here---------------start------------->8---
(gnutls-negotiate :process (open-network-stream name buffer host service)
                  :type 'gnutls-x509pki
                  :hostname host)
--8<---------------cut here---------------end--------------->8---

There is NO way to set :verify-host, :verify-flags, etc. for this call
to `gnutls-negotiate' when using gnutls via high-level functions like
`open-network-stream'.

I consider this a bug, as Emacs won't check any certificates and
therefore allow man in the middle attacks without even documenting this.

It should at least be possible to pass :verify-* from
`open-network-stream' down to `gnutls-negotiate'. That would be a simple
yet effective solution.


In GNU Emacs 24.3.1 (x86_64-apple-darwin11.4.2, NS apple-appkit-1138.51)
 of 2013-03-05 on Moritzs-MacBook-Air
Windowing system distributor `Apple', version 10.3.1138
Configured using:
 `configure '--prefix=/usr/local/Cellar/emacs/24.3-rc1' '--without-dbus'
 '--enable-locallisppath=/usr/local/share/emacs/site-lisp'
 '--infodir=/usr/local/Cellar/emacs/24.3-rc1/share/info/emacs'
 '--with-ns' '--disable-ns-self-contained' '--with-gnutls' '--with-jpeg'
 '--with-xml2' '--with-imagemagick' 'CC=cc''

<#secure method=pgpmime mode=sign>

-- 
Moritz Ulrich

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From: Ted Zlatanov <tzz <at> lifelogs.com>
To: Stefan Monnier <monnier <at> iro.umontreal.ca>
Cc: Oleksii Shevchuk <alxchk <at> gmail.com>,
 Lars Magne Ingebrigtsen <larsi <at> gnus.org>, 13374-done <at> debbugs.gnu.org
Subject: Re: bug#13374: 24.?; open-gnutls-stream insecurity
Date: Wed, 18 Dec 2013 17:50:39 -0500

On Tue, 08 Jan 2013 12:06:08 -0500 Stefan Monnier <monnier <at> iro.umontreal.ca> wrote: 

>>> It should default to nil (in other words, we'll ship 24.3 with the same
>>> insecure behavior it has right now).  But we can recommend to the users
>>> to turn it on, and see how well it works in practice, and write the
>>> necessary prompts and customization logic that Lars outlined.
>> I think we should just leave things as is for 24.3, since it's too close
>> to release, and fix this properly for 24.5.

SM> I tend to agree, although, if the patch is sufficiently trivial, it
SM> could be accepted (e.g. define a new custom var, with nil default value
SM> and splice it somewhere in the code where nil makes no difference).

>> Instituting an option like that (which will have to be abandoned
>> later) as a stop-gap I feel isn't all that helpful.

SM> If the option will have to be abandoned, then it's indeed a loser, but
SM> I thought the idea is that this option will stay and the added code in
SM> 24.4 will "simply" be handling errors more cleverly and prompting the
SM> user to update this option on-the-fly.

This is done for the upcoming release.  Marking this as done.

Ted

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