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=-5.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT 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 ABE2AC433F4 for ; Mon, 24 Sep 2018 12:34:15 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 705D721486 for ; Mon, 24 Sep 2018 12:34:15 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 705D721486 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=linuxfoundation.org Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2388307AbeIXSgI (ORCPT ); Mon, 24 Sep 2018 14:36:08 -0400 Received: from mail.linuxfoundation.org ([140.211.169.12]:58408 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2387489AbeIXSgH (ORCPT ); Mon, 24 Sep 2018 14:36:07 -0400 Received: from localhost (ip-213-127-77-73.ip.prioritytelecom.net [213.127.77.73]) by mail.linuxfoundation.org (Postfix) with ESMTPSA id 76F381018; Mon, 24 Sep 2018 12:34:11 +0000 (UTC) From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, syzbot+c75f181dc8429d2eb887@syzkaller.appspotmail.com, Miklos Szeredi Subject: [PATCH 4.18 108/235] ovl: fix oopses in ovl_fill_super() failure paths Date: Mon, 24 Sep 2018 13:51:34 +0200 Message-Id: <20180924113116.469311945@linuxfoundation.org> X-Mailer: git-send-email 2.19.0 In-Reply-To: <20180924113103.999624566@linuxfoundation.org> References: <20180924113103.999624566@linuxfoundation.org> User-Agent: quilt/0.65 X-stable: review MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 4.18-stable review patch. If anyone has any objections, please let me know. ------------------ From: Miklos Szeredi commit 8c25741aaad8be6fbe51510e917c740e0059cf83 upstream. ovl_free_fs() dereferences ofs->workbasedir and ofs->upper_mnt in cases when those might not have been initialized yet. Fix the initialization order for these fields. Reported-by: syzbot+c75f181dc8429d2eb887@syzkaller.appspotmail.com Signed-off-by: Miklos Szeredi Cc: # v4.15 Fixes: 95e6d4177cb7 ("ovl: grab reference to workbasedir early") Fixes: a9075cdb467d ("ovl: factor out ovl_free_fs() helper") Signed-off-by: Greg Kroah-Hartman --- fs/overlayfs/super.c | 26 ++++++++++++++------------ 1 file changed, 14 insertions(+), 12 deletions(-) --- a/fs/overlayfs/super.c +++ b/fs/overlayfs/super.c @@ -970,16 +970,6 @@ static int ovl_get_upper(struct ovl_fs * if (err) goto out; - err = -EBUSY; - if (ovl_inuse_trylock(upperpath->dentry)) { - ofs->upperdir_locked = true; - } else if (ofs->config.index) { - pr_err("overlayfs: upperdir is in-use by another mount, mount with '-o index=off' to override exclusive upperdir protection.\n"); - goto out; - } else { - pr_warn("overlayfs: upperdir is in-use by another mount, accessing files from both mounts will result in undefined behavior.\n"); - } - upper_mnt = clone_private_mount(upperpath); err = PTR_ERR(upper_mnt); if (IS_ERR(upper_mnt)) { @@ -990,6 +980,17 @@ static int ovl_get_upper(struct ovl_fs * /* Don't inherit atime flags */ upper_mnt->mnt_flags &= ~(MNT_NOATIME | MNT_NODIRATIME | MNT_RELATIME); ofs->upper_mnt = upper_mnt; + + err = -EBUSY; + if (ovl_inuse_trylock(ofs->upper_mnt->mnt_root)) { + ofs->upperdir_locked = true; + } else if (ofs->config.index) { + pr_err("overlayfs: upperdir is in-use by another mount, mount with '-o index=off' to override exclusive upperdir protection.\n"); + goto out; + } else { + pr_warn("overlayfs: upperdir is in-use by another mount, accessing files from both mounts will result in undefined behavior.\n"); + } + err = 0; out: return err; @@ -1089,8 +1090,10 @@ static int ovl_get_workdir(struct ovl_fs goto out; } + ofs->workbasedir = dget(workpath.dentry); + err = -EBUSY; - if (ovl_inuse_trylock(workpath.dentry)) { + if (ovl_inuse_trylock(ofs->workbasedir)) { ofs->workdir_locked = true; } else if (ofs->config.index) { pr_err("overlayfs: workdir is in-use by another mount, mount with '-o index=off' to override exclusive workdir protection.\n"); @@ -1099,7 +1102,6 @@ static int ovl_get_workdir(struct ovl_fs pr_warn("overlayfs: workdir is in-use by another mount, accessing files from both mounts will result in undefined behavior.\n"); } - ofs->workbasedir = dget(workpath.dentry); err = ovl_make_workdir(ofs, &workpath); if (err) goto out;