From nobody Tue Apr 8 14:35:17 2025 Delivered-To: importer@patchew.org Authentication-Results: mx.zohomail.com; dkim=pass; spf=pass (zohomail.com: domain of gnu.org designates 209.51.188.17 as permitted sender) smtp.mailfrom=qemu-devel-bounces+importer=patchew.org@nongnu.org; dmarc=pass(p=none dis=none) header.from=redhat.com ARC-Seal: i=1; a=rsa-sha256; t=1625836553; cv=none; d=zohomail.com; s=zohoarc; b=VOwYfyvz/u5fBUMYa/c/QZqQyhVeIsf8G90z5/Cif+1vZeUAjaHIneeiA5vtXDIOuc6u0dPFVRVoXRBKRbRQTRq9Y/3vLA22Qm8U0PfQLdc2pBofHc9jBNrkXDZESB+TPP/+ePHd26D1Jty95R0AfLWovTXiGvB3vCOO0ghe8ng= ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=zohomail.com; s=zohoarc; t=1625836553; h=Content-Type:Content-Transfer-Encoding:Cc:Date:From:In-Reply-To:List-Subscribe:List-Post:List-Id:List-Archive:List-Help:List-Unsubscribe:MIME-Version:Message-ID:References:Sender:Subject:To; bh=QxRwftzqyfTQy1eYSzuxJVJfqV4RQxmj77YtVCNirRQ=; b=Y+SFEqU7kGHHuC49anglyfTIxh0NjQSlYjme065jtSmF9yLiDfKheDGECwaPicwEXwRWDwJ5uuBr9r9xm/X9XyXDARuHAURQUyenVBgI269mkZuTy24x6LbBbRad6W1GrhBxG4X3yKia0wJrmllcIi7VoVrLxei0gRHYNbrmJ5I= ARC-Authentication-Results: i=1; mx.zohomail.com; dkim=pass; spf=pass (zohomail.com: domain of gnu.org designates 209.51.188.17 as permitted sender) smtp.mailfrom=qemu-devel-bounces+importer=patchew.org@nongnu.org; dmarc=pass header.from= (p=none dis=none) Return-Path: Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) by mx.zohomail.com with SMTPS id 1625836553876318.62877958261004; Fri, 9 Jul 2021 06:15:53 -0700 (PDT) Received: from localhost ([::1]:50146 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1m1qMC-0005Sd-Qf for importer@patchew.org; Fri, 09 Jul 2021 09:15:52 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:57746) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1m1pzI-00055z-7f for qemu-devel@nongnu.org; Fri, 09 Jul 2021 08:52:12 -0400 Received: from us-smtp-delivery-124.mimecast.com ([170.10.133.124]:24202) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1m1pzG-0003k6-HU for qemu-devel@nongnu.org; Fri, 09 Jul 2021 08:52:11 -0400 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-86-njW0bZlaO4e8RXXjVr1pIQ-1; Fri, 09 Jul 2021 08:52:07 -0400 Received: from smtp.corp.redhat.com (int-mx03.intmail.prod.int.phx2.redhat.com [10.5.11.13]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 9519C801107; Fri, 9 Jul 2021 12:52:06 +0000 (UTC) Received: from merkur.redhat.com (ovpn-113-203.ams2.redhat.com [10.36.113.203]) by smtp.corp.redhat.com (Postfix) with ESMTP id B550360843; Fri, 9 Jul 2021 12:52:04 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1625835130; 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=QxRwftzqyfTQy1eYSzuxJVJfqV4RQxmj77YtVCNirRQ=; b=jWpCpSWGlnlDg45lkCcHv1qEem8Sh2ZjImIDpevNonXmjQkqnqexJfPYCJ1khty7u2pePo JkCioFJR0axjE+nEUs1kv72vIt48N6PQTkdZD8xBf63XQA8mzqCKQay8NO2stW8lvKLOC6 UjCW8pbC19E3vLMe8xgJXiP9YA7VNwY= X-MC-Unique: njW0bZlaO4e8RXXjVr1pIQ-1 From: Kevin Wolf To: qemu-block@nongnu.org Subject: [PULL 23/28] qcow2: Fix dangling pointer after reopen for 'file' Date: Fri, 9 Jul 2021 14:50:30 +0200 Message-Id: <20210709125035.191321-24-kwolf@redhat.com> In-Reply-To: <20210709125035.191321-1-kwolf@redhat.com> References: <20210709125035.191321-1-kwolf@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.79 on 10.5.11.13 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-Transfer-Encoding: quoted-printable Received-SPF: pass (zohomail.com: domain of gnu.org designates 209.51.188.17 as permitted sender) client-ip=209.51.188.17; envelope-from=qemu-devel-bounces+importer=patchew.org@nongnu.org; helo=lists.gnu.org; Received-SPF: pass client-ip=170.10.133.124; envelope-from=kwolf@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -31 X-Spam_score: -3.2 X-Spam_bar: --- X-Spam_report: (-3.2 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.45, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_LOW=-0.7, RCVD_IN_MSPIKE_H4=0.001, RCVD_IN_MSPIKE_WL=0.001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=unavailable autolearn_force=no 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: kwolf@redhat.com, peter.maydell@linaro.org, qemu-devel@nongnu.org Errors-To: qemu-devel-bounces+importer=patchew.org@nongnu.org Sender: "Qemu-devel" X-ZohoMail-DKIM: pass (identity @redhat.com) X-ZM-MESSAGEID: 1625836554926100001 Content-Type: text/plain; charset="utf-8" Without an external data file, s->data_file is a second pointer with the same value as bs->file. When changing bs->file to a different BdrvChild and freeing the old BdrvChild, s->data_file must also be updated, otherwise it points to freed memory and causes crashes. This problem was caught by iotests case 245. Fixes: df2b7086f169239ebad5d150efa29c9bb6d4f820 Signed-off-by: Kevin Wolf Message-Id: <20210708114709.206487-2-kwolf@redhat.com> Reviewed-by: Eric Blake Reviewed-by: Vladimir Sementsov-Ogievskiy Signed-off-by: Kevin Wolf --- block/qcow2.c | 29 +++++++++++++++++++++++++++++ 1 file changed, 29 insertions(+) diff --git a/block/qcow2.c b/block/qcow2.c index 0cac2eda36..9f1b6461c8 100644 --- a/block/qcow2.c +++ b/block/qcow2.c @@ -1926,6 +1926,7 @@ static void qcow2_refresh_limits(BlockDriverState *bs= , Error **errp) static int qcow2_reopen_prepare(BDRVReopenState *state, BlockReopenQueue *queue, Error **errp) { + BDRVQcow2State *s =3D state->bs->opaque; Qcow2ReopenState *r; int ret; =20 @@ -1956,6 +1957,16 @@ static int qcow2_reopen_prepare(BDRVReopenState *sta= te, } } =20 + /* + * Without an external data file, s->data_file points to the same Bdrv= Child + * as bs->file. It needs to be resynced after reopen because bs->file = may + * be changed. We can't use it in the meantime. + */ + if (!has_data_file(state->bs)) { + assert(s->data_file =3D=3D state->bs->file); + s->data_file =3D NULL; + } + return 0; =20 fail: @@ -1966,7 +1977,16 @@ fail: =20 static void qcow2_reopen_commit(BDRVReopenState *state) { + BDRVQcow2State *s =3D state->bs->opaque; + qcow2_update_options_commit(state->bs, state->opaque); + if (!s->data_file) { + /* + * If we don't have an external data file, s->data_file was cleare= d by + * qcow2_reopen_prepare() and needs to be updated. + */ + s->data_file =3D state->bs->file; + } g_free(state->opaque); } =20 @@ -1990,6 +2010,15 @@ static void qcow2_reopen_commit_post(BDRVReopenState= *state) =20 static void qcow2_reopen_abort(BDRVReopenState *state) { + BDRVQcow2State *s =3D state->bs->opaque; + + if (!s->data_file) { + /* + * If we don't have an external data file, s->data_file was cleare= d by + * qcow2_reopen_prepare() and needs to be restored. + */ + s->data_file =3D state->bs->file; + } qcow2_update_options_abort(state->bs, state->opaque); g_free(state->opaque); } --=20 2.31.1