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=-10.5 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,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 A531BC43610 for ; Mon, 26 Nov 2018 11:01:47 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 6EE2C2147D for ; Mon, 26 Nov 2018 11:01:47 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=kernel.org header.i=@kernel.org header.b="NRzbiVpg" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 6EE2C2147D 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 S1730255AbeKZVz3 (ORCPT ); Mon, 26 Nov 2018 16:55:29 -0500 Received: from mail.kernel.org ([198.145.29.99]:38114 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1730225AbeKZVz3 (ORCPT ); Mon, 26 Nov 2018 16:55:29 -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 4DA192089F; Mon, 26 Nov 2018 11:01:43 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1543230103; bh=Zn/dWbpF52aaY8L36izbzep9rDgW2jj3HJkn9m/IlEg=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=NRzbiVpg9YiRlJ2fx7qxQF5nJGXlHJnD6MTB9/2fyfJPu/8o3aEM14sNBC5ayMW8Z k/Nf6U54Zn+8U269K3O3bLR1l4fzRQEzdOIgcDJWnrXym9Eu1OPwgmuntDupsc5dOm nJinIZzus41+mMlT1vLuJIUmRGUFzHpY39LBEkJg= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Colin Ian King , Steve French , Sasha Levin Subject: [PATCH 4.19 002/118] cifs: dont dereference smb_file_target before null check Date: Mon, 26 Nov 2018 11:49:56 +0100 Message-Id: <20181126105059.927220946@linuxfoundation.org> X-Mailer: git-send-email 2.19.2 In-Reply-To: <20181126105059.832485122@linuxfoundation.org> References: <20181126105059.832485122@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. ------------------ [ Upstream commit 8c6c9bed8773375b1d54ccca2911ec892c59db5d ] There is a null check on dst_file->private data which suggests it can be potentially null. However, before this check, pointer smb_file_target is derived from dst_file->private and dereferenced in the call to tlink_tcon, hence there is a potential null pointer deference. Fix this by assigning smb_file_target and target_tcon after the null pointer sanity checks. Detected by CoverityScan, CID#1475302 ("Dereference before null check") Fixes: 04b38d601239 ("vfs: pull btrfs clone API to vfs layer") Signed-off-by: Colin Ian King Signed-off-by: Steve French Signed-off-by: Sasha Levin --- fs/cifs/cifsfs.c | 7 +++++-- 1 file changed, 5 insertions(+), 2 deletions(-) diff --git a/fs/cifs/cifsfs.c b/fs/cifs/cifsfs.c index 7065426b3280..fb32f3d6925e 100644 --- a/fs/cifs/cifsfs.c +++ b/fs/cifs/cifsfs.c @@ -981,8 +981,8 @@ static int cifs_clone_file_range(struct file *src_file, loff_t off, struct inode *src_inode = file_inode(src_file); struct inode *target_inode = file_inode(dst_file); struct cifsFileInfo *smb_file_src = src_file->private_data; - struct cifsFileInfo *smb_file_target = dst_file->private_data; - struct cifs_tcon *target_tcon = tlink_tcon(smb_file_target->tlink); + struct cifsFileInfo *smb_file_target; + struct cifs_tcon *target_tcon; unsigned int xid; int rc; @@ -996,6 +996,9 @@ static int cifs_clone_file_range(struct file *src_file, loff_t off, goto out; } + smb_file_target = dst_file->private_data; + target_tcon = tlink_tcon(smb_file_target->tlink); + /* * Note: cifs case is easier than btrfs since server responsible for * checks for proper open modes and file type and if it wants -- 2.17.1