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=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 9CBD8C433DF for ; Tue, 16 Jun 2020 15:59:23 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 7C160207C4 for ; Tue, 16 Jun 2020 15:59:23 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1592323163; bh=jekqzddmXorLFHyyC5EL7qj8S8lyLz0vDRMB0nadoCg=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=GdEJv8j3FSJiHP3L7zybHU97RDp9zXesP3FLSeYJJ1+4JyNnAKBrvgm/MUBMrBJaA Nt5S6boIv5I2A1tQmU4gmlG/LJDJyQqLWUPywfrM2/4NasE4tnL+69Eay3Snf6NC4r SyqwcOVMPDSO8IUQ3aOPOhudYxNVScs0NgalrrV0= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1732190AbgFPP7W (ORCPT ); Tue, 16 Jun 2020 11:59:22 -0400 Received: from mail.kernel.org ([198.145.29.99]:52062 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1732891AbgFPPxl (ORCPT ); Tue, 16 Jun 2020 11:53:41 -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 1311E207C4; Tue, 16 Jun 2020 15:53:39 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1592322820; bh=jekqzddmXorLFHyyC5EL7qj8S8lyLz0vDRMB0nadoCg=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=tjPwPXyw0dNtlZKqKTKA4ElVkdl8sdPV4tp+5GmEFtYD0YcTfnUWzzgph9Lc9nQ8C MIXvrQ+tiwENeexkVmdei2b5o/iNH9dTiPy51rg43kzVw30Ox0/rPxByYamjTXPphh pfFe4ac+EldnXk46yTOVlwK6p2lE7DYR7gIW5v8M= 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 5.6 116/161] ovl: initialize error in ovl_copy_xattr Date: Tue, 16 Jun 2020 17:35:06 +0200 Message-Id: <20200616153111.882703317@linuxfoundation.org> X-Mailer: git-send-email 2.27.0 In-Reply-To: <20200616153106.402291280@linuxfoundation.org> References: <20200616153106.402291280@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 @@ -40,7 +40,7 @@ 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) ||