From patchwork Fri Jun 19 14:31:38 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Greg KH X-Patchwork-Id: 223710 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 49596C433E0 for ; Fri, 19 Jun 2020 16:38:55 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 1E9702067D for ; Fri, 19 Jun 2020 16:38:55 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1592584735; bh=x7B5wod4MBfR1dx5pVObIqXplMbNsgaIgDDQQ7vpFEE=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=TgZ1j+q6hlTX8eJ+pxiH7zUnmERdDwlLwXzGqBCKVEi2AbcxUR77xm5J3ydcta6fq QAcrt8Zfv68BG3LcRtI2QB496XJIabmQjKaNDO8JCARGxwRSdaXtjMfD/CXQ89M2dg sg1fxZxzfVwues/s8LOtR1+HeXTuE6v/Ol7aqXJA= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2395361AbgFSQiy (ORCPT ); Fri, 19 Jun 2020 12:38:54 -0400 Received: from mail.kernel.org ([198.145.29.99]:39146 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2388918AbgFSOrI (ORCPT ); Fri, 19 Jun 2020 10:47:08 -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 9A12C20DD4; Fri, 19 Jun 2020 14:47:06 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1592578027; bh=x7B5wod4MBfR1dx5pVObIqXplMbNsgaIgDDQQ7vpFEE=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=nIAxzxX5xpBLbv5hoCKsNmV0r/cm2zmmxyfnapu/hAwIg3iBrCAfmDUM00ELCjdjt OKRvy9VibByANbxlD36aA2XuspT2YzIgP0GJGI6IbPy0Cy4RfFKECLwyOnNCfZDwsY 4ITDz8yrND5sF6+kI7XnlG6fSV5J2iK48HgQ6j18= 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 4.14 053/190] ovl: initialize error in ovl_copy_xattr Date: Fri, 19 Jun 2020 16:31:38 +0200 Message-Id: <20200619141636.236038789@linuxfoundation.org> X-Mailer: git-send-email 2.27.0 In-Reply-To: <20200619141633.446429600@linuxfoundation.org> References: <20200619141633.446429600@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Sender: stable-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: stable@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 @@ -59,7 +59,7 @@ 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) ||