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=-3.6 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 417B3C4BA3B for ; Thu, 27 Feb 2020 09:44:27 +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 0B8982467F for ; Thu, 27 Feb 2020 09:44:26 +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="hZ2efe/E" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 0B8982467F 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]:56162 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1j7FiU-00078E-6O for qemu-devel@archiver.kernel.org; Thu, 27 Feb 2020 04:44:26 -0500 Received: from eggs.gnu.org ([2001:470:142:3::10]:55481) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1j7FhY-0006YG-CV for qemu-devel@nongnu.org; Thu, 27 Feb 2020 04:43:29 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1j7FhW-0006NX-Hd for qemu-devel@nongnu.org; Thu, 27 Feb 2020 04:43:27 -0500 Received: from us-smtp-delivery-1.mimecast.com ([205.139.110.120]:22928 helo=us-smtp-1.mimecast.com) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1j7FhV-0006Mm-QM for qemu-devel@nongnu.org; Thu, 27 Feb 2020 04:43:26 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1582796604; 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=AxJD58PkEqCuECClxO2X8LUJ08wREGf8GLDkzyUvyGM=; b=hZ2efe/EtYPqLBQzmbPmXCDv8h32MiPRxCFH+kymKZz3i2oHM9B18Lo5RvNrAbDqwnz1X1 wDqYIFAy77FDjKxQQRkBO909chAm9mjzDBBGcHO/Ht11P/81WigmfY0okBcftGQL4WQKCA CkTnanEzTRqjgtX8Mjx/a0sbLnlAzAU= 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-318-YS8LMF6KNemesNsqYM49hw-1; Thu, 27 Feb 2020 04:43:22 -0500 X-MC-Unique: YS8LMF6KNemesNsqYM49hw-1 Received: from smtp.corp.redhat.com (int-mx07.intmail.prod.int.phx2.redhat.com [10.5.11.22]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 870191922960; Thu, 27 Feb 2020 09:43:21 +0000 (UTC) Received: from lpt (unknown [10.43.2.81]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 52EA01001DC0; Thu, 27 Feb 2020 09:43:17 +0000 (UTC) Date: Thu, 27 Feb 2020 10:43:14 +0100 From: =?iso-8859-1?B?SuFu?= Tomko To: Eric Blake Subject: Re: [PATCH v2 3/3] qemu-img: Deprecate use of -b without -F Message-ID: <20200227094314.GF2262365@lpt> References: <20200227023928.1021959-1-eblake@redhat.com> <20200227023928.1021959-4-eblake@redhat.com> MIME-Version: 1.0 In-Reply-To: <20200227023928.1021959-4-eblake@redhat.com> X-Scanned-By: MIMEDefang 2.84 on 10.5.11.22 X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Type: multipart/signed; micalg=pgp-sha256; protocol="application/pgp-signature"; boundary="CXFpZVxO6m2Ol4tQ" Content-Disposition: inline X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] X-Received-From: 205.139.110.120 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: Kevin Wolf , pkrempa@redhat.com, qemu-block@nongnu.org, 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" --CXFpZVxO6m2Ol4tQ Content-Type: text/plain; charset=us-ascii; format=flowed Content-Disposition: inline On a Wednesday in 2020, Eric Blake wrote: >Creating an image that requires format probing of the backing image is >inherently unsafe (we've had several CVEs over the years based on >probes leaking information to the guest on a subsequent boot). If our >probing algorithm ever changes, or if other tools like libvirt >determine a different probe result than we do, then subsequent use of >that backing file under a different format will present corrupted data >to the guest. Start a deprecation clock so that future qemu-img can >refuse to create unsafe backing chains that would rely on probing. > >However, there is one time where probing is safe: if we probe raw, >then it is safe to record that implicitly in the image (but we still >warn, as it's better to teach the user to supply -F always than to >make them guess when it is safe). > >iotest 114 specifically wants to create an unsafe image for later >amendment rather than defaulting to our new default of recording a >probed format, so it needs an update. > >Signed-off-by: Eric Blake >--- > qemu-deprecated.texi | 15 +++++++++++++++ > block.c | 21 ++++++++++++++++++++- > qemu-img.c | 8 +++++++- > tests/qemu-iotests/114 | 4 ++-- > tests/qemu-iotests/114.out | 1 + > 5 files changed, 45 insertions(+), 4 deletions(-) > This seems to affect code paths that are used even outside of qemu-img, should the commit message mention it? 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