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=-6.5 required=3.0 tests=DKIM_INVALID,DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS autolearn=ham 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 8D729CA9EC1 for ; Mon, 28 Oct 2019 13:03:36 +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 5BD0820717 for ; Mon, 28 Oct 2019 13:03:36 +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="A8TRoQTf" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 5BD0820717 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]:53512 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1iP4gI-0003N0-Cd for qemu-devel@archiver.kernel.org; Mon, 28 Oct 2019 09:03:34 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:50790) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1iP3x2-0002tI-EB for qemu-devel@nongnu.org; Mon, 28 Oct 2019 08:16:50 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1iP3wx-0001zi-Hn for qemu-devel@nongnu.org; Mon, 28 Oct 2019 08:16:45 -0400 Received: from us-smtp-1.mimecast.com ([207.211.31.81]:21801 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 1iP3wu-0001xV-6Y for qemu-devel@nongnu.org; Mon, 28 Oct 2019 08:16:40 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1572264999; 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=rDRhJaImYLPxs5FqXhGCslMsXlMubC4w5oQ2JKHYQkw=; b=A8TRoQTfhgMttdZRwJFY4/9r1mpD4Ed4BHa8ZUo3Kxr+9TSAY8SCbQtID+RdZl2qy3SClD Ae0eFNUyAaw1YRufi3yChjDFj1PMDJzYtU3bGerNdQUzerGmUmF3T6YEXHJLNx8HM6b13e nT9Agzb1Fa8GgeaNXoxupkAv4myZM0w= 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-387-G6eGbPJqNc6_PWx_pvxb0A-1; Mon, 28 Oct 2019 08:16:35 -0400 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 69D98180496E; Mon, 28 Oct 2019 12:16:34 +0000 (UTC) Received: from localhost (ovpn-117-83.ams2.redhat.com [10.36.117.83]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 0F0EB5D6BB; Mon, 28 Oct 2019 12:16:33 +0000 (UTC) From: Max Reitz To: qemu-block@nongnu.org Subject: [PULL 44/69] mirror: Do not dereference invalid pointers Date: Mon, 28 Oct 2019 13:14:36 +0100 Message-Id: <20191028121501.15279-45-mreitz@redhat.com> In-Reply-To: <20191028121501.15279-1-mreitz@redhat.com> References: <20191028121501.15279-1-mreitz@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.79 on 10.5.11.15 X-MC-Unique: G6eGbPJqNc6_PWx_pvxb0A-1 X-Mimecast-Spam-Score: 0 Content-Type: text/plain; charset=US-ASCII 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: 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: Kevin Wolf , Peter Maydell , qemu-devel@nongnu.org, Max Reitz Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" mirror_exit_common() may be called twice (if it is called from mirror_prepare() and fails, it will be called from mirror_abort() again). In such a case, many of the pointers in the MirrorBlockJob object will already be freed. This can be seen most reliably for s->target, which is set to NULL (and then dereferenced by blk_bs()). Cc: qemu-stable@nongnu.org Fixes: 737efc1eda23b904fbe0e66b37715fb0e5c3e58b Signed-off-by: Max Reitz Reviewed-by: John Snow Reviewed-by: Vladimir Sementsov-Ogievskiy Message-id: 20191014153931.20699-2-mreitz@redhat.com Signed-off-by: Max Reitz --- block/mirror.c | 13 +++++++++---- 1 file changed, 9 insertions(+), 4 deletions(-) diff --git a/block/mirror.c b/block/mirror.c index 454365ce00..bb17cfce31 100644 --- a/block/mirror.c +++ b/block/mirror.c @@ -620,11 +620,11 @@ static int mirror_exit_common(Job *job) { MirrorBlockJob *s =3D container_of(job, MirrorBlockJob, common.job); BlockJob *bjob =3D &s->common; - MirrorBDSOpaque *bs_opaque =3D s->mirror_top_bs->opaque; + MirrorBDSOpaque *bs_opaque; AioContext *replace_aio_context =3D NULL; - BlockDriverState *src =3D s->mirror_top_bs->backing->bs; - BlockDriverState *target_bs =3D blk_bs(s->target); - BlockDriverState *mirror_top_bs =3D s->mirror_top_bs; + BlockDriverState *src; + BlockDriverState *target_bs; + BlockDriverState *mirror_top_bs; Error *local_err =3D NULL; bool abort =3D job->ret < 0; int ret =3D 0; @@ -634,6 +634,11 @@ static int mirror_exit_common(Job *job) } s->prepared =3D true; =20 + mirror_top_bs =3D s->mirror_top_bs; + bs_opaque =3D mirror_top_bs->opaque; + src =3D mirror_top_bs->backing->bs; + target_bs =3D blk_bs(s->target); + if (bdrv_chain_contains(src, target_bs)) { bdrv_unfreeze_backing_chain(mirror_top_bs, target_bs); } --=20 2.21.0