From patchwork Sun Sep 15 20:36:53 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Maxim Levitsky X-Patchwork-Id: 1162554 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@bilbo.ozlabs.org Authentication-Results: ozlabs.org; spf=pass (mailfrom) smtp.mailfrom=nongnu.org (client-ip=209.51.188.17; helo=lists.gnu.org; envelope-from=qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org; receiver=) Authentication-Results: ozlabs.org; dmarc=fail (p=none dis=none) header.from=redhat.com 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 ozlabs.org (Postfix) with ESMTPS id 46Wh640J5Hz9sNx for ; Mon, 16 Sep 2019 06:38:17 +1000 (AEST) Received: from localhost ([::1]:56994 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1i9bHi-0003Jp-6s for incoming@patchwork.ozlabs.org; Sun, 15 Sep 2019 16:38:14 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:45801) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1i9bGf-00032L-NR for qemu-devel@nongnu.org; Sun, 15 Sep 2019 16:37:10 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1i9bGe-0000ew-DX for qemu-devel@nongnu.org; Sun, 15 Sep 2019 16:37:09 -0400 Received: from mx1.redhat.com ([209.132.183.28]:48682) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1i9bGZ-0000bQ-QB; Sun, 15 Sep 2019 16:37:04 -0400 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 mx1.redhat.com (Postfix) with ESMTPS id BA68C85362; Sun, 15 Sep 2019 20:37:02 +0000 (UTC) Received: from maximlenovopc.usersys.redhat.com (unknown [10.35.206.40]) by smtp.corp.redhat.com (Postfix) with ESMTP id 8ACF05C1D6; Sun, 15 Sep 2019 20:37:00 +0000 (UTC) From: Maxim Levitsky To: qemu-devel@nongnu.org Date: Sun, 15 Sep 2019 23:36:53 +0300 Message-Id: <20190915203655.21638-2-mlevitsk@redhat.com> In-Reply-To: <20190915203655.21638-1-mlevitsk@redhat.com> References: <20190915203655.21638-1-mlevitsk@redhat.com> X-Scanned-By: MIMEDefang 2.79 on 10.5.11.16 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.25]); Sun, 15 Sep 2019 20:37:02 +0000 (UTC) X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] X-Received-From: 209.132.183.28 Subject: [Qemu-devel] [PATCH v7 1/3] block/qcow2: Fix corruption introduced by commit 8ac0f15f335 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 , Vladimir Sementsov-Ogievskiy , =?utf-8?q?Daniel_P_=2E_Berrang=C3=A9?= , qemu-block@nongnu.org, qemu-stable , Max Reitz , Maxim Levitsky Errors-To: qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org Sender: "Qemu-devel" This fixes subtle corruption introduced by luks threaded encryption in commit 8ac0f15f335 Bugzilla: https://bugzilla.redhat.com/show_bug.cgi?id=1745922 The corruption happens when we do a write that * writes to two or more unallocated clusters at once * doesn't fully cover the first sector * doesn't fully cover the last sector * uses luks encryption In this case, when allocating the new clusters we COW both areas prior to the write and after the write, and we encrypt them. The above mentioned commit accidentally made it so we encrypt the second COW area using the physical cluster offset of the first area. The problem is that offset_in_cluster in do_perform_cow_encrypt can be larger that the cluster size, thus cluster_offset will no longer point to the start of the cluster at which encrypted area starts. Next patch in this series will refactor the code to avoid all these assumptions. In the bugreport that was triggered by rebasing a luks image to new, zero filled base, which lot of such writes, and causes some files with zero areas to contain garbage there instead. But as described above it can happen elsewhere as well Signed-off-by: Maxim Levitsky Reviewed-by: Vladimir Sementsov-Ogievskiy Reviewed-by: Max Reitz --- block/qcow2-cluster.c | 7 ++++--- 1 file changed, 4 insertions(+), 3 deletions(-) diff --git a/block/qcow2-cluster.c b/block/qcow2-cluster.c index dcacd3c450..bfeb0241d7 100644 --- a/block/qcow2-cluster.c +++ b/block/qcow2-cluster.c @@ -474,9 +474,10 @@ static bool coroutine_fn do_perform_cow_encrypt(BlockDriverState *bs, assert((offset_in_cluster & ~BDRV_SECTOR_MASK) == 0); assert((bytes & ~BDRV_SECTOR_MASK) == 0); assert(s->crypto); - if (qcow2_co_encrypt(bs, cluster_offset, - src_cluster_offset + offset_in_cluster, - buffer, bytes) < 0) { + if (qcow2_co_encrypt(bs, + start_of_cluster(s, cluster_offset + offset_in_cluster), + src_cluster_offset + offset_in_cluster, + buffer, bytes) < 0) { return false; } }