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=-3.5 required=3.0 tests=DKIM_INVALID,DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE, SPF_PASS 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 D7FB9C433DF for ; Tue, 7 Jul 2020 16:42:14 +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 A1B5D2064C for ; Tue, 7 Jul 2020 16:42:14 +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="eyP5naRn" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org A1B5D2064C 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]:47234 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1jsqfd-0002KN-Sn for qemu-devel@archiver.kernel.org; Tue, 07 Jul 2020 12:42:13 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:60412) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1jsq7n-0003h4-4h for qemu-devel@nongnu.org; Tue, 07 Jul 2020 12:07:15 -0400 Received: from us-smtp-delivery-1.mimecast.com ([207.211.31.120]:37087 helo=us-smtp-1.mimecast.com) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_CBC_SHA1:256) (Exim 4.90_1) (envelope-from ) id 1jsq7j-00073K-Q9 for qemu-devel@nongnu.org; Tue, 07 Jul 2020 12:07:14 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1594138030; 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: in-reply-to:in-reply-to:references:references; bh=/YiqAr9e+eEUFPbEdoIPErTXKb+7N1FxdAz6Kj1cMjk=; b=eyP5naRnIPtOV0lrrDHAyIo9mYrAdttN0DNRvZJbdoBYp3CtmgweHrJgeQLTfu3bXit6T0 x6UL+zghmR93TseAPM1SLbRhMDQ3xtdVZ4d9LTfjCnnURGe02Ek/XkWERkD98QHHt/VB0Z hKpwv/Boi6swMsZ2eX3xdSoamSIb51w= 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-189-rzJUfY8hN8e80_fpEPf_fw-1; Tue, 07 Jul 2020 12:07:08 -0400 X-MC-Unique: rzJUfY8hN8e80_fpEPf_fw-1 Received: from smtp.corp.redhat.com (int-mx05.intmail.prod.int.phx2.redhat.com [10.5.11.15]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id C265A10059A8; Tue, 7 Jul 2020 16:07:07 +0000 (UTC) Received: from linux.fritz.box (ovpn-114-113.ams2.redhat.com [10.36.114.113]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 0654473FD7; Tue, 7 Jul 2020 16:07:02 +0000 (UTC) Date: Tue, 7 Jul 2020 18:07:01 +0200 From: Kevin Wolf To: Eric Blake Subject: Re: [PATCH v6 08/10] iotests: Specify explicit backing format where sensible Message-ID: <20200707160701.GE7002@linux.fritz.box> References: <20200706203954.341758-1-eblake@redhat.com> <20200706203954.341758-9-eblake@redhat.com> MIME-Version: 1.0 In-Reply-To: <20200706203954.341758-9-eblake@redhat.com> X-Scanned-By: MIMEDefang 2.79 on 10.5.11.15 Authentication-Results: relay.mimecast.com; auth=pass smtp.auth=CUSA124A263 smtp.mailfrom=kwolf@redhat.com X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Received-SPF: pass client-ip=207.211.31.120; envelope-from=kwolf@redhat.com; helo=us-smtp-1.mimecast.com X-detected-operating-system: by eggs.gnu.org: First seen = 2020/07/07 00:46:09 X-ACL-Warn: Detected OS = Linux 2.2.x-3.x [generic] [fuzzy] X-Spam_score_int: -40 X-Spam_score: -4.1 X-Spam_bar: ---- X-Spam_report: (-4.1 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-1, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_NONE=-0.0001, RCVD_IN_MSPIKE_H2=-1, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=_AUTOLEARN X-Spam_action: no action 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: pkrempa@redhat.com, qemu-block@nongnu.org, kchamart@redhat.com, libvir-list@redhat.com, qemu-devel@nongnu.org, mreitz@redhat.com Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" Am 06.07.2020 um 22:39 hat Eric Blake geschrieben: > There are many existing qcow2 images that specify a backing file but > no format. This has been the source of CVEs in the past, but has > become more prominent of a problem now that libvirt has switched to > -blockdev. With older -drive, at least the probing was always done by > qemu (so the only risk of a changed format between successive boots of > a guest was if qemu was upgraded and probed differently). But with > newer -blockdev, libvirt must specify a format; if libvirt guesses raw > where the image was formatted, this results in data corruption visible > to the guest; conversely, if libvirt guesses qcow2 where qemu was > using raw, this can result in potential security holes, so modern > libvirt instead refuses to use images without explicit backing format. > > The change in libvirt to reject images without explicit backing format > has pointed out that a number of tools have been far too reliant on > probing in the past. It's time to set a better example in our own > iotests of properly setting this parameter. > > iotest calls to create, rebase, and convert are all impacted to some > degree. It's a bit annoying that we are inconsistent on command line > - while all of those accept -o backing_file=...,backing_fmt=..., the > shortcuts are different: create and rebase have -b and -F, while > convert has -B but no -F. (amend has no shortcuts, but the previous > patch just deprecated the use of amend to change backing chains). > > Signed-off-by: Eric Blake This breaks at least 024 and 043 for qed because qemu-img info can't print the backing file format there (qed only saves a flag whether it's raw or non-raw). We can fix the output filtering during the freeze, though. Kevin