From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mp1 ([2001:41d0:2:4a6f::]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits)) by ms11 with LMTPS id wDhmMjbax14bfgAA0tVLHw (envelope-from ) for ; Fri, 22 May 2020 13:57:10 +0000 Received: from aspmx1.migadu.com ([2001:41d0:2:4a6f::]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits)) by mp1 with LMTPS id gFkgLjbax14xYwAAbx9fmQ (envelope-from ) for ; Fri, 22 May 2020 13:57:10 +0000 Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by aspmx1.migadu.com (Postfix) with ESMTPS id 419C094038E for ; Fri, 22 May 2020 13:57:10 +0000 (UTC) Received: from localhost ([::1]:33914 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1jc8Ae-0008Uh-SB for larch@yhetil.org; Fri, 22 May 2020 09:57:08 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:52316) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1jc8AZ-0008UM-5a for guix-patches@gnu.org; Fri, 22 May 2020 09:57:03 -0400 Received: from debbugs.gnu.org ([209.51.188.43]:48366) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_128_GCM_SHA256:128) (Exim 4.90_1) (envelope-from ) id 1jc8AY-0003Vw-Nj for guix-patches@gnu.org; Fri, 22 May 2020 09:57:02 -0400 Received: from Debian-debbugs by debbugs.gnu.org with local (Exim 4.84_2) (envelope-from ) id 1jc8AY-0000lR-C7 for guix-patches@gnu.org; Fri, 22 May 2020 09:57:02 -0400 X-Loop: help-debbugs@gnu.org Subject: [bug#41425] [PATCH 0/5] Have 'guix pull' protect against downgrade attacks Resent-From: Ludovic =?UTF-8?Q?Court=C3=A8s?= Original-Sender: "Debbugs-submit" Resent-CC: guix-patches@gnu.org Resent-Date: Fri, 22 May 2020 13:57:02 +0000 Resent-Message-ID: Resent-Sender: help-debbugs@gnu.org X-GNU-PR-Message: followup 41425 X-GNU-PR-Package: guix-patches X-GNU-PR-Keywords: patch To: zimoun Cc: 41425@debbugs.gnu.org Received: via spool by 41425-submit@debbugs.gnu.org id=B41425.15901557812908 (code B ref 41425); Fri, 22 May 2020 13:57:02 +0000 Received: (at 41425) by debbugs.gnu.org; 22 May 2020 13:56:21 +0000 Received: from localhost ([127.0.0.1]:59912 helo=debbugs.gnu.org) by debbugs.gnu.org with esmtp (Exim 4.84_2) (envelope-from ) id 1jc89t-0000kq-46 for submit@debbugs.gnu.org; Fri, 22 May 2020 09:56:21 -0400 Received: from eggs.gnu.org ([209.51.188.92]:44836) by debbugs.gnu.org with esmtp (Exim 4.84_2) (envelope-from ) id 1jc89d-0000kS-8f for 41425@debbugs.gnu.org; Fri, 22 May 2020 09:56:19 -0400 Received: from fencepost.gnu.org ([2001:470:142:3::e]:48762) by eggs.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1jc89X-0003Mc-KG; Fri, 22 May 2020 09:55:59 -0400 Received: from [2a01:e0a:1d:7270:af76:b9b:ca24:c465] (port=49326 helo=ribbon) by fencepost.gnu.org with esmtpsa (TLS1.2:RSA_AES_256_CBC_SHA1:256) (Exim 4.82) (envelope-from ) id 1jc89W-0001to-Uz; Fri, 22 May 2020 09:55:59 -0400 From: Ludovic =?UTF-8?Q?Court=C3=A8s?= References: <20200520213802.2170-1-ludo@gnu.org> X-URL: http://www.fdn.fr/~lcourtes/ X-Revolutionary-Date: 4 Prairial an 228 de la =?UTF-8?Q?R=C3=A9volution?= X-PGP-Key-ID: 0x090B11993D9AEBB5 X-PGP-Key: http://www.fdn.fr/~lcourtes/ludovic.asc X-PGP-Fingerprint: 3CE4 6455 8A84 FDC6 9DB4 0CFB 090B 1199 3D9A EBB5 X-OS: x86_64-pc-linux-gnu Date: Fri, 22 May 2020 15:55:56 +0200 In-Reply-To: (zimoun's message of "Thu, 21 May 2020 16:06:27 +0200") Message-ID: <87r1vc9iqb.fsf@gnu.org> User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/26.3 (gnu/linux) MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable X-Spam-Score: 0.0 (/) X-BeenThere: debbugs-submit@debbugs.gnu.org X-Mailman-Version: 2.1.18 Precedence: list X-Spam-Score: -3.3 (---) X-BeenThere: guix-patches@gnu.org List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: guix-patches-bounces+larch=yhetil.org@gnu.org Sender: "Guix-patches" X-Scanner: scn0 Authentication-Results: aspmx1.migadu.com; dkim=none; dmarc=none; spf=pass (aspmx1.migadu.com: domain of guix-patches-bounces@gnu.org designates 209.51.188.17 as permitted sender) smtp.mailfrom=guix-patches-bounces@gnu.org X-Spam-Score: -1.01 X-TUID: XkjyNufKExTj Hi Simon, zimoun skribis: > On Wed, 20 May 2020 at 23:39, Ludovic Court=C3=A8s wrote: > >> By default =E2=80=98guix pull=E2=80=99 would now error out if the target= commit of a >> channel is not a descendant of the currently-used commit, according to >> the commit graph. There=E2=80=99s an option to bypass that. =E2=80=98g= uix >> time-machine=E2=80=99 behavior is unchanged though: it never complains. > > What is the extra time cost of such check? The problem is not the cost. =E2=80=98guix pull=E2=80=99 compares the targ= et commit(s) against the commit(s) of the currently-used =E2=80=98guix=E2=80=99; it can = clearly see if it=E2=80=99s a forward pull or not. However, in the case of =E2=80=98guix time-machine=E2=80=99, there=E2=80=99= s nothing to compare against (it=E2=80=99s a bit like a fresh =E2=80=98git clone=E2=80=99 as opp= osed to a =E2=80=98git pull=E2=80=99, if you see what I mean.) Additionally, the purpose of =E2=80=98guix time-machine=E2=80=99 is to trav= el in time, usually in the past, so it would be inconvenient to get warnings or errors every time. > It is not easy -- nor impossible -- to evaluate such cost at the level > of "guix pull". And I failed to evaluate it using 'commit-relation' > with "guix repl" -- Segmentation fault with commit > c81457a5883ea43950eb2ecdcbb58a5b144bcd11 and > 4bdf4182fe080c3409f6ef9b410146b67cfa2595; probably because I did used > correctly the API. How can I reproduce the issue? > Well, what will be the timing impact of checking the "fast-fowardness"? I haven=E2=80=99t measured it, but it=E2=80=99s small compared to the cost = of fetching the new revisions and performing the checkout. It=E2=80=99s roughly what = =E2=80=98git pull=E2=80=99 does, although =E2=80=98git pull=E2=80=99 is probably faster = because it=E2=80=99s in C and has been well optimized over the years. Thanks for your feedback! Ludo=E2=80=99.