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 1ABA0C433E0 for ; Tue, 16 Jun 2020 15:39:56 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id EB82820C56 for ; Tue, 16 Jun 2020 15:39:55 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1592321996; bh=jekqzddmXorLFHyyC5EL7qj8S8lyLz0vDRMB0nadoCg=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=BVm5fALHXsB2e1mjHI50AxcJkefG6OgUeCRYJnihAm922v5ssmDOJbjyfRVZZQQjV 3MjBeyo2smb5yl/3CQDglFbnTeW5lUGc96LiB/yhoREmH7yJRGOSEoWwAU7BHzDEX0 4AyDX50eAg5emoqhTPda901Gi2IHiZNGTRbfWTZQ= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1731053AbgFPPjy (ORCPT ); Tue, 16 Jun 2020 11:39:54 -0400 Received: from mail.kernel.org ([198.145.29.99]:53772 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1731038AbgFPPjv (ORCPT ); Tue, 16 Jun 2020 11:39:51 -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 1E70220B1F; Tue, 16 Jun 2020 15:39:49 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1592321990; bh=jekqzddmXorLFHyyC5EL7qj8S8lyLz0vDRMB0nadoCg=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=fmDz/UGVpiQOv/T1aMxSDnb0kMFiM/JjhGQ6Fd9zn0N8aetmsYVCHwW3bIc6br1Pt 2ymf6x7h2MMOqyB6F9gON2RR14vaCe34EwzmVIucVQcHzY+TszDFoDLnoE8uglFxXB Z12J172iU4X7FTeyBSZS3NURvt2kKVpe6xNJjeXs= 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 5.4 094/134] ovl: initialize error in ovl_copy_xattr Date: Tue, 16 Jun 2020 17:34:38 +0200 Message-Id: <20200616153105.281938125@linuxfoundation.org> X-Mailer: git-send-email 2.27.0 In-Reply-To: <20200616153100.633279950@linuxfoundation.org> References: <20200616153100.633279950@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) ||