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=-2.1 required=3.0 tests=DKIM_INVALID,DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, 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 878AAC10F27 for ; Mon, 9 Mar 2020 16:14:38 +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 53ECF2464B for ; Mon, 9 Mar 2020 16:14:38 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="dD2zWXli" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 53ECF2464B 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]:46352 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1jBL37-0002L4-Eo for qemu-devel@archiver.kernel.org; Mon, 09 Mar 2020 12:14:37 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:42837) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1jBKmW-0006Dk-Dr for qemu-devel@nongnu.org; Mon, 09 Mar 2020 11:57:29 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1jBKmV-0000h9-AB for qemu-devel@nongnu.org; Mon, 09 Mar 2020 11:57:28 -0400 Received: from us-smtp-1.mimecast.com ([207.211.31.81]:23500 helo=us-smtp-delivery-1.mimecast.com) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1jBKmV-0000gB-3D for qemu-devel@nongnu.org; Mon, 09 Mar 2020 11:57:27 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1583769446; h=from:from: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: in-reply-to:in-reply-to:references:references; bh=sM6wzIxkfI44re0KY8Dat2S2LMsIRmYZXOzMvLj+MvU=; b=dD2zWXliKcdCZJxDGgES+d3WfWOL+bXyg/HuNXvNHI89cjiIov5F9KTjW4Je5hrDn0dZfe VTmBtq2ISMmhaGfp88ZOHOWQhThRu1KDXlB7lLSiLyB7Ivwy2CvmMazL8A+jHY69uPy7cz 9weDFfvVhyfDIkCpJwTq/yYy+QqEnnw= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-249-F7tyqmS2M5-8vcEfcsYSRA-1; Mon, 09 Mar 2020 11:57:22 -0400 X-MC-Unique: F7tyqmS2M5-8vcEfcsYSRA-1 Received: from smtp.corp.redhat.com (int-mx06.intmail.prod.int.phx2.redhat.com [10.5.11.16]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 7645D18C35B2; Mon, 9 Mar 2020 15:57:20 +0000 (UTC) Received: from linux.fritz.box (ovpn-116-162.ams2.redhat.com [10.36.116.162]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 244205C557; Mon, 9 Mar 2020 15:57:14 +0000 (UTC) Date: Mon, 9 Mar 2020 16:57:13 +0100 From: Kevin Wolf To: Daniel =?iso-8859-1?Q?P=2E_Berrang=E9?= Subject: Re: [PATCH v3 1/4] block: Add trivial backing_fmt support to qcow, sheepdog, vmdk Message-ID: <20200309155713.GE6478@linux.fritz.box> References: <20200306225121.3199279-1-eblake@redhat.com> <20200306225121.3199279-2-eblake@redhat.com> <20200309152112.GC6478@linux.fritz.box> <7b7f12f8-ca03-12d4-b93d-2edefb51cb42@redhat.com> <20200309154412.GL3033513@redhat.com> MIME-Version: 1.0 In-Reply-To: <20200309154412.GL3033513@redhat.com> User-Agent: Mutt/1.12.1 (2019-06-15) X-Scanned-By: MIMEDefang 2.79 on 10.5.11.16 X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Type: text/plain; charset=iso-8859-1 Content-Transfer-Encoding: quoted-printable Content-Disposition: inline X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] [fuzzy] X-Received-From: 207.211.31.81 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: Fam Zheng , pkrempa@redhat.com, "open list:Sheepdog" , qemu-block@nongnu.org, libvir-list@redhat.com, Michael Tokarev , qemu-devel@nongnu.org, mreitz@redhat.com, "open list:Trivial patches" , Liu Yuan , Laurent Vivier Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" Am 09.03.2020 um 16:44 hat Daniel P. Berrang=E9 geschrieben: > We could support "-F ..." and validate any non-raw formats, while raising= a > runtime error in the case of "-F raw", as only the "raw" backing format h= as > the probing security risk. >=20 > Users who need to use qcow, with a backing file, without a format can > just not pass "-F" and in doing so will be insecure. Hm, this is actually an interesting option. We wouldn't lose features compared to today without -F, but we would allow -F when we can verify that the operation is safe (the image is already non-raw). > We could take this opportunity to deprecate 'qcow' perhaps, declare it > a read-only format, restricted to qemu-img/qemu-io for purpose of data > liberation ? I'm against making any format read-only because that immediately means that it becomes untestable. > For sheepdog, if it is something we genuinely still care about, then > adding a backing file format record seems neccessary, unless we either > forbid use of raw backing files, or forbid use of non-raw backing files, > either way would be safe. In case of doubt, we can use the same logic as you suggested for qcow (accept only non-raw with -F, but no restrictions without -F). Kevin