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=-7.5 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,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 5D5A2C43441 for ; Mon, 19 Nov 2018 16:32:15 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 23D062086A for ; Mon, 19 Nov 2018 16:32:15 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=kernel.org header.i=@kernel.org header.b="K5xntIsF" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 23D062086A 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 S1730675AbeKTC4U (ORCPT ); Mon, 19 Nov 2018 21:56:20 -0500 Received: from mail.kernel.org ([198.145.29.99]:54466 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729986AbeKTC4T (ORCPT ); Mon, 19 Nov 2018 21:56:19 -0500 Received: from localhost (5356596B.cm-6-7b.dynamic.ziggo.nl [83.86.89.107]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id BFF1220831; Mon, 19 Nov 2018 16:32:11 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1542645132; bh=UOUbMG6JTK5p+/RSpta4xzAcdiUEFZPAn9lahf5ysgE=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=K5xntIsF3Us+O78iK0Rlp5KkiqB+MI/YNQ4ci/vhWu4B7Bu211+ZbX4bbq53FsnGH MTiGxLNgHGXnbyaCkU/vZYaDVZii7jBJoODOYGV1ASfqefZ3i+RiYThGgcAljGEdC7 juhdWzsBZ+KmwEhmAPFRWJ38Vt2tuR/4ehm5pDdY= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Miklos Szeredi Subject: [PATCH 4.19 048/205] ovl: check whiteout in ovl_create_over_whiteout() Date: Mon, 19 Nov 2018 17:25:55 +0100 Message-Id: <20181119162625.920232189@linuxfoundation.org> X-Mailer: git-send-email 2.19.1 In-Reply-To: <20181119162616.586062722@linuxfoundation.org> References: <20181119162616.586062722@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 4.19-stable review patch. If anyone has any objections, please let me know. ------------------ From: Miklos Szeredi commit 5e1275808630ea3b2c97c776f40e475017535f72 upstream. Kaixuxia repors that it's possible to crash overlayfs by removing the whiteout on the upper layer before creating a directory over it. This is a reproducer: mkdir lower upper work merge touch lower/file mount -t overlay overlay -olowerdir=lower,upperdir=upper,workdir=work merge rm merge/file ls -al merge/file rm upper/file ls -al merge/ mkdir merge/file Before commencing with a vfs_rename(..., RENAME_EXCHANGE) verify that the lookup of "upper" is positive and is a whiteout, and return ESTALE otherwise. Reported by: kaixuxia Signed-off-by: Miklos Szeredi Fixes: e9be9d5e76e3 ("overlay filesystem") Cc: # v3.18 Signed-off-by: Greg Kroah-Hartman --- fs/overlayfs/dir.c | 4 ++++ 1 file changed, 4 insertions(+) --- a/fs/overlayfs/dir.c +++ b/fs/overlayfs/dir.c @@ -463,6 +463,10 @@ static int ovl_create_over_whiteout(stru if (IS_ERR(upper)) goto out_unlock; + err = -ESTALE; + if (d_is_negative(upper) || !IS_WHITEOUT(d_inode(upper))) + goto out_dput; + newdentry = ovl_create_temp(workdir, cattr); err = PTR_ERR(newdentry); if (IS_ERR(newdentry))