From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mout.gmx.com (mout.gmx.com [74.208.4.200]) (using TLSv1.2 with cipher DHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.server123.net (Postfix) with ESMTPS for ; Wed, 30 Nov 2016 05:16:20 +0100 (CET) Received: from ulgy_thing ([174.228.134.51]) by mail.gmx.com (mrgmxus001 [74.208.5.15]) with ESMTPSA (Nemesis) id 0LdHvD-1ccmbv0Zfd-00iSrs for ; Wed, 30 Nov 2016 05:11:10 +0100 Date: Tue, 29 Nov 2016 09:56:28 -0500 From: David Niklas Message-ID: <20161129095628.145ec2ac@ulgy_thing> In-Reply-To: <20161116134826.GD17781@tansi.org> References: <2aa32b7a-8aa4-bd7a-c6f0-eaef3794e8e8@whgl.uni-frankfurt.de> <20161115231546.GN19581@yeono.kjorling.se> <10ad5d6f-faf4-e71e-d528-67054db1f4ae@whgl.uni-frankfurt.de> <20161115235254.GA13171@tansi.org> <70a8f691-e02e-c2c9-b206-0e2bc028e113@freesources.org> <20161116134826.GD17781@tansi.org> MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Subject: Re: [dm-crypt] About CVE-2016-4484: - Cryptsetup Initrd root Shell List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: dm-crypt@saout.de On Wed, 16 Nov 2016 14:48:27 Arno Wagner wrote: > On Wed, Nov 16, 2016 at 08:32:12 CET, Milan Broz wrote: > > On 11/16/2016 02:15 AM, Sven Eschenberg wrote: > > ... > > > > > > There's a whole bunch of headlines among these lines. I've read > > > that cryptsetup has a vulnerability exposing a root-shell on an > > > encrypted system. Not quite so. > > > > Yes, this is the real "contribution" of reporting a bug with > > (possibly even unrelated) project name in headlines. > > > > But seems users themselves correct some stupid article comments, > > thanks for it! ;-) > > > > Sometimes I wish security is less theater and more responsibility... > > (This bug cost me hours of explanation that upstream has nothing to > > fix and that in fact the cryptsetup/LUKS worked as designed.) > > Tell me about it. I have these discussions regularly as a > security consultant, simply because a lack of understanding > on customer side and attribution of errors by keyword-matching > instead. > > I think I will add a new section to the FAQ dealing with initrd > issues. > Contens: > 1) No, the initrd is _not_ part of cryptsetup, it is your > distro that screwed up if it is broken or insecure. > 2) If you depend on the initrd doing something seucrely, > roll your own and lock that down. > 3) (Maybe an example...) > > Regards, > Arno > Personally, I've know about this for years (because I could not remember my password one day), and I thought it was helpful to be able to drop to a shell when cryptsetup does not return 0. Great debugging aide if you wrote something wrong in the intrid. Besides, if I was truly an evil attacker with physical access, surly I could come up with a better attack then this one (Change out the cpu/CMOS/BIOS with an evil one! No more TPE! No more Intel TxT! No more *secure* hardware crypto devices! Etc.!!!). Sincerely, David