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=-6.8 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT autolearn=unavailable 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 D67EEC433DF for ; Fri, 19 Jun 2020 16:48:09 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id A9BEE204EC for ; Fri, 19 Jun 2020 16:48:09 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1592585289; bh=an4Pmc8XjI0h6GPlpDzwEw973xGTuUCS6+ncmNpufzk=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=X1c3dBEzgoSo+LbBtjECbS1bs9kU0bmVaLLXZcfT4ooS6Tpra9aLSvgXojFezk2Zm lAeeMjRh5Yh8QyZ3v/yVvCB+RjmUbpvrJajavVk45PowURIivbxe/kW61XDFDLSBD0 4LKa6mthTCfrZ4hOrFBtoek4BizgghaSf4Ex91iU= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2405739AbgFSQsD (ORCPT ); Fri, 19 Jun 2020 12:48:03 -0400 Received: from mail.kernel.org ([198.145.29.99]:59070 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2388182AbgFSOkx (ORCPT ); Fri, 19 Jun 2020 10:40:53 -0400 Received: from localhost (83-86-89-107.cable.dynamic.v4.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 ED6082070A; Fri, 19 Jun 2020 14:40:52 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1592577653; bh=an4Pmc8XjI0h6GPlpDzwEw973xGTuUCS6+ncmNpufzk=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=y0q+ePDeZ7Vh7wAN5dfHjR4ieo+kTn6V3xKGzzxTED+ignRxOVkqx78R2kKWMYal8 use+BkqX3FnegCdVUdPyzFajqXFFYjvHuMzYowfNvYLCPDI5zDdffF4TJaw6UAqjSV 32h97YaBjWDn/lRCv07y9w0mmerBUxZLzF3C1yyU= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Yuxuan Shui , Alexander Potapenko , Miklos Szeredi Subject: [PATCH 4.9 035/128] ovl: initialize error in ovl_copy_xattr Date: Fri, 19 Jun 2020 16:32:09 +0200 Message-Id: <20200619141622.053348936@linuxfoundation.org> X-Mailer: git-send-email 2.27.0 In-Reply-To: <20200619141620.148019466@linuxfoundation.org> References: <20200619141620.148019466@linuxfoundation.org> User-Agent: quilt/0.66 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 From: Yuxuan Shui commit 520da69d265a91c6536c63851cbb8a53946974f0 upstream. In ovl_copy_xattr, if all the xattrs to be copied are overlayfs private xattrs, the copy loop will terminate without assigning anything to the error variable, thus returning an uninitialized value. If ovl_copy_xattr is called from ovl_clear_empty, this uninitialized error value is put into a pointer by ERR_PTR(), causing potential invalid memory accesses down the line. This commit initialize error with 0. This is the correct value because when there's no xattr to copy, because all xattrs are private, ovl_copy_xattr should succeed. This bug is discovered with the help of INIT_STACK_ALL and clang. Signed-off-by: Yuxuan Shui Link: https://bugs.chromium.org/p/chromium/issues/detail?id=1050405 Fixes: 0956254a2d5b ("ovl: don't copy up opaqueness") Cc: stable@vger.kernel.org # v4.8 Signed-off-by: Alexander Potapenko Signed-off-by: Miklos Szeredi Signed-off-by: Greg Kroah-Hartman --- fs/overlayfs/copy_up.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) --- a/fs/overlayfs/copy_up.c +++ b/fs/overlayfs/copy_up.c @@ -56,7 +56,7 @@ int ovl_copy_xattr(struct dentry *old, s { ssize_t list_size, size, value_size = 0; char *buf, *name, *value = NULL; - int uninitialized_var(error); + int error = 0; size_t slen; if (!(old->d_inode->i_opflags & IOP_XATTR) ||