From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-2.2 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_SANE_1 autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 12585CA9EA1 for ; Fri, 18 Oct 2019 13:31:16 +0000 (UTC) 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 mail.kernel.org (Postfix) with ESMTPS id DE8AF2064A for ; Fri, 18 Oct 2019 13:31:15 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org DE8AF2064A Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=redhat.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Received: from localhost ([::1]:40038 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1iLSLa-0004zz-W6 for qemu-devel@archiver.kernel.org; Fri, 18 Oct 2019 09:31:15 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:51819) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1iLSKj-0004MR-Ij for qemu-devel@nongnu.org; Fri, 18 Oct 2019 09:30:23 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1iLSKi-0004HQ-HC for qemu-devel@nongnu.org; Fri, 18 Oct 2019 09:30:21 -0400 Received: from mx1.redhat.com ([209.132.183.28]:16219) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1iLSKg-0004FD-6g; Fri, 18 Oct 2019 09:30:18 -0400 Received: from smtp.corp.redhat.com (int-mx04.intmail.prod.int.phx2.redhat.com [10.5.11.14]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id 4FD77A3CD81; Fri, 18 Oct 2019 13:30:17 +0000 (UTC) Received: from [10.3.116.168] (ovpn-116-168.phx2.redhat.com [10.3.116.168]) by smtp.corp.redhat.com (Postfix) with ESMTPS id A943D5D9CA; Fri, 18 Oct 2019 13:30:16 +0000 (UTC) Subject: Re: [PATCH v2 01/23] iotests: Introduce $SOCK_DIR To: Max Reitz , qemu-block@nongnu.org References: <20191017133155.5327-1-mreitz@redhat.com> <20191017133155.5327-2-mreitz@redhat.com> <1ea69391-fa2b-bb19-ce34-f47036f1a064@redhat.com> From: Eric Blake Organization: Red Hat, Inc. Message-ID: Date: Fri, 18 Oct 2019 08:30:16 -0500 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.1.0 MIME-Version: 1.0 In-Reply-To: <1ea69391-fa2b-bb19-ce34-f47036f1a064@redhat.com> Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US X-Scanned-By: MIMEDefang 2.79 on 10.5.11.14 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.6.2 (mx1.redhat.com [10.5.110.68]); Fri, 18 Oct 2019 13:30:17 +0000 (UTC) Content-Transfer-Encoding: quoted-printable X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] [fuzzy] X-Received-From: 209.132.183.28 X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Thomas Huth , qemu-devel@nongnu.org Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" On 10/18/19 4:03 AM, Max Reitz wrote: >>> =C2=A0 -if [ ! -e "$TEST_DIR" ]; then >>> -=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0 mkdir "$TEST_DIR" >>> +tmp_sock_dir=3Dfalse >>> +if [ -z "$SOCK_DIR" ]; then >>> +=C2=A0=C2=A0=C2=A0 SOCK_DIR=3D$(mktemp -d) >>> +=C2=A0=C2=A0=C2=A0 tmp_sock_dir=3Dtrue >>> =C2=A0 fi >>> +mkdir -p "$SOCK_DIR" || _init_error 'Failed to create SOCK_DIR' >> >> Thinking about this again: if the user passed in a name, we probably >> want to use it no matter whether the directory already exists (mkdir -= p >> makes sense: either the directory did not exist, or the user is in >> charge of passing us a directory that they already secured).=C2=A0 But= if we >> generate our own name in a world-writable location in /tmp, using mkdi= r >> -p means someone else can race us to the creation of the directory, an= d >> potentially populate it in a way to cause us a security hole while we >> execute our tests. >=20 > I don=E2=80=99t quite see how this is a security hole. mktemp -d creat= es the > directory, so noone can race us. Aha - I confused 'mktemp -u' (necessary for creating a socket name) and=20 'mktemp -d' (for directories). With that confusion cleared up, yes, the=20 directory is safely created (or else the burden is on the caller), so: Reviewed-by: Eric Blake --=20 Eric Blake, Principal Software Engineer Red Hat, Inc. +1-919-301-3226 Virtualization: qemu.org | libvirt.org