From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mp0 ([2001:41d0:8:6d80::]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) by ms0.migadu.com with LMTPS id yOmnKNpMbGArygAAgWs5BA (envelope-from ) for ; Tue, 06 Apr 2021 13:58:18 +0200 Received: from aspmx1.migadu.com ([2001:41d0:8:6d80::]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits)) by mp0 with LMTPS id QAKbItpMbGBCMgAA1q6Kng (envelope-from ) for ; Tue, 06 Apr 2021 11:58:18 +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 EE828240FA for ; Tue, 6 Apr 2021 13:58:17 +0200 (CEST) Received: from localhost ([::1]:38444 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1lTkLX-0003i2-1Y for larch@yhetil.org; Tue, 06 Apr 2021 07:58:15 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:58898) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1lTkLM-0003ho-Ez for bug-guix@gnu.org; Tue, 06 Apr 2021 07:58:04 -0400 Received: from debbugs.gnu.org ([209.51.188.43]:56086) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_128_GCM_SHA256:128) (Exim 4.90_1) (envelope-from ) id 1lTkLM-0006Ix-6r for bug-guix@gnu.org; Tue, 06 Apr 2021 07:58:04 -0400 Received: from Debian-debbugs by debbugs.gnu.org with local (Exim 4.84_2) (envelope-from ) id 1lTkLK-0002pk-4x for bug-guix@gnu.org; Tue, 06 Apr 2021 07:58:03 -0400 X-Loop: help-debbugs@gnu.org Subject: bug#47584: Race condition in =?UTF-8?Q?=E2=80=98copy-account-skeletons=E2=80=99:?= possible privilege escalation. Resent-From: Ludovic =?UTF-8?Q?Court=C3=A8s?= Original-Sender: "Debbugs-submit" Resent-CC: bug-guix@gnu.org Resent-Date: Tue, 06 Apr 2021 11:58:02 +0000 Resent-Message-ID: Resent-Sender: help-debbugs@gnu.org X-GNU-PR-Message: followup 47584 X-GNU-PR-Package: guix X-GNU-PR-Keywords: security patch To: Maxime Devos Received: via spool by 47584-submit@debbugs.gnu.org id=B47584.161771024210843 (code B ref 47584); Tue, 06 Apr 2021 11:58:02 +0000 Received: (at 47584) by debbugs.gnu.org; 6 Apr 2021 11:57:22 +0000 Received: from localhost ([127.0.0.1]:39399 helo=debbugs.gnu.org) by debbugs.gnu.org with esmtp (Exim 4.84_2) (envelope-from ) id 1lTkKg-0002op-Bk for submit@debbugs.gnu.org; Tue, 06 Apr 2021 07:57:22 -0400 Received: from eggs.gnu.org ([209.51.188.92]:37502) by debbugs.gnu.org with esmtp (Exim 4.84_2) (envelope-from ) id 1lTkKd-0002ob-UX for 47584@debbugs.gnu.org; Tue, 06 Apr 2021 07:57:21 -0400 Received: from fencepost.gnu.org ([2001:470:142:3::e]:48624) by eggs.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1lTkKX-0005qN-W0; Tue, 06 Apr 2021 07:57:14 -0400 Received: from [2a01:e0a:1d:7270:af76:b9b:ca24:c465] (port=37184 helo=ribbon) by fencepost.gnu.org with esmtpsa (TLS1.2:RSA_AES_256_CBC_SHA1:256) (Exim 4.82) (envelope-from ) id 1lTkKU-00012l-2L; Tue, 06 Apr 2021 07:57:13 -0400 From: Ludovic =?UTF-8?Q?Court=C3=A8s?= References: <1a6ed722dfdd96dc8d53f939aa8e440ca7c29213.camel@telenet.be> <87mtufw1kh.fsf@gnu.org> <7ab30aad812e5de1216c95b3becb784e3363e615.camel@telenet.be> <87zgycqzfz.fsf@gnu.org> <00621260aa43f1918aaf0f0bb2318bf359b826c3.camel@telenet.be> X-URL: http://www.fdn.fr/~lcourtes/ X-Revolutionary-Date: 17 Germinal an 229 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: Tue, 06 Apr 2021 13:57:08 +0200 In-Reply-To: <00621260aa43f1918aaf0f0bb2318bf359b826c3.camel@telenet.be> (Maxime Devos's message of "Tue, 06 Apr 2021 11:56:23 +0200") Message-ID: <87v98zmxrf.fsf@gnu.org> User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/27.2 (gnu/linux) MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable X-BeenThere: debbugs-submit@debbugs.gnu.org X-Mailman-Version: 2.1.18 Precedence: list X-BeenThere: bug-guix@gnu.org List-Id: Bug reports for GNU Guix List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: 47584@debbugs.gnu.org Errors-To: bug-guix-bounces+larch=yhetil.org@gnu.org Sender: "bug-Guix" X-Migadu-Flow: FLOW_IN ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=yhetil.org; s=key1; t=1617710298; h=from:from:sender:sender:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type: content-transfer-encoding:content-transfer-encoding:resent-cc: resent-from:resent-sender:resent-message-id:in-reply-to:in-reply-to: references:references:list-id:list-help:list-unsubscribe: list-subscribe:list-post; bh=DsEUl7zpJo83yBWG5DUBH0zrYKtharYHSeqjWkHb7PE=; b=a14R+HXCpjvdwMpSZIrRTL+BOC2v0lycnAXv42KYonmSqkgDoEZteUNV/StN9XnhrgkXFT VKmFAtlP4SOkds6XvXmI5o3RzYz7Ja69/vkD/zuCiJqsxtA+6/iYY9rQ87hOkBRUYIbGKq 5wWVlD8dEUt1ZPPnjYWTp7OrDLddaI7ldYztQAnzqQh6sH9NLiEWvsronbEJ8M00yD1zwS pnKaKOORcTBlr03AhAb3OsOOmD3SQVh44TXMZ6EUsz2lapZijdRhPk4/2KtUTKjOXykSfr TxGCCOF7bOdjFxeYaejfIrYTqfDjZmFJKIrv7DUCJ/B9dqOlSFwiqKPRmBu8SA== ARC-Seal: i=1; s=key1; d=yhetil.org; t=1617710298; a=rsa-sha256; cv=none; b=h2D6UMgkbAX711qzEDTpBLVXm0rOlrCDGJOdDllzOD9IZoRAGh8finCsK3W1GNJBClm+Km djmnM3jWgQzJpL+Mmql9dK6c4q1wkDecWG+EdpwCrqYJyXLVgS4srEQF1QNGOyUmW134mw /AKz74rR9JoQ9Uqj0E93gaejNQhEQu+vGGaD9nFmN5oSCaV0CVwM6u9dpsoqYrhdAeFJk1 sLdkZ4R6z+IRB1NxhbnmY2QPspUvm8dcZBmXQ5HDu8tRcGChYR6RHG4M8IIL+ZSRCZyC9B pKmq9S4VBI3/RwTCMOmn5kwV0yXIMoj2J/TwvOiPL4IJ+OYNmLw0kgMArqGO1g== ARC-Authentication-Results: i=1; aspmx1.migadu.com; dkim=none; spf=pass (aspmx1.migadu.com: domain of bug-guix-bounces@gnu.org designates 209.51.188.17 as permitted sender) smtp.mailfrom=bug-guix-bounces@gnu.org X-Migadu-Spam-Score: -2.03 Authentication-Results: aspmx1.migadu.com; dkim=none; dmarc=pass (policy=none) header.from=gnu.org; spf=pass (aspmx1.migadu.com: domain of bug-guix-bounces@gnu.org designates 209.51.188.17 as permitted sender) smtp.mailfrom=bug-guix-bounces@gnu.org X-Migadu-Queue-Id: EE828240FA X-Spam-Score: -2.03 X-Migadu-Scanner: scn0.migadu.com X-TUID: lowN4bu3vmoy Hi Maxime, Maxime Devos skribis: > On Mon, 2021-04-05 at 21:54 +0200, Ludovic Court=C3=A8s wrote: >> [...] >>=20 >> OK. It does mean that the bug is hardly exploitable in practice: you >> have to be able to log in at all, > Yes. > >> and if you=E2=80=99re able to log in, you have >> to log in precisely within the 1s (or less) that follows account >> creation, which sounds challenging (TCP + SSH connection establishment >> is likely to take as much time or more, > > Is logging in possible when the home directory doesn't exist? I think so. > An attacker could copy and paste, or have used a single-character passwor= d, > to save some time. Hmm yes. It=E2=80=99s a bit a far-fetched though: the attacker would have passed the sysadmin the output of the =E2=80=98crypt=E2=80=99 procedure, su= ch that the sysadmin cannot know the password length. >> Does it warrant as strong messaging as for the recent daemon >> =E2=80=98--keep-failed=E2=80=99 vulnerability? > > As it is a one-time chance, with a limited window, and only under specific > circumstances (creating a new user account), I don't think so. But I wou= ld > still recommend to upgrade. Does the blog post have =E2=80=98too strong = messaging=E2=80=99?=20 The blog post and info-guix messages are the highest levels of visibility we can give, roughly. So I think we have to think twice before doing that or truly important issues will eventually go unnoticed. The risk with this issue seems much lower than that of the keep-failed issue, it even looks super low. WDYT? Ludo=E2=80=99.