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,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 15B8CC47257 for ; Mon, 4 May 2020 18:10:46 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id E2F642496F for ; Mon, 4 May 2020 18:10:45 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1588615846; bh=NlVxoTjNVIj7k425iDGce3uuUKxG2Mo4IPPMlgN5liw=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=eqlduKsECGWhIQiZMxAHcPAZ3tm6QAeaz8P3X39vqpHpozKtBNFddJKwflBhbxbWb TsRG+YgFKC+ELFcWD01ApIVjUIsJFT9w2gU96m8Vxwa6+QiLe0lbOdPrYvGNDFtrz8 be1cJwzSU8VwkTMgt093L0I34mC+glH/0RrrpWyQ= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1732092AbgEDSKo (ORCPT ); Mon, 4 May 2020 14:10:44 -0400 Received: from mail.kernel.org ([198.145.29.99]:34736 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1731207AbgEDSFD (ORCPT ); Mon, 4 May 2020 14:05:03 -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 E6F022073E; Mon, 4 May 2020 18:05:02 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1588615503; bh=NlVxoTjNVIj7k425iDGce3uuUKxG2Mo4IPPMlgN5liw=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=gNSXXKklWzKUgIWXXw3F4/3hgrP7QaL2KhUUhnHKT26f3MRchQ21PPY4ir6Ea7hng Bh3Hhwm9LwuZamCmknRrA/SC56Eq3nFMZCBdKO8WvahK3Nrvpw+EunFPE4+h9AoHzL qR0Oypm1T/iwuJXN/rK4niGWMCUbcHWmuYAUZHMc= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Al Viro Subject: [PATCH 5.4 26/57] dlmfs_file_write(): fix the bogosity in handling non-zero *ppos Date: Mon, 4 May 2020 19:57:30 +0200 Message-Id: <20200504165458.613322756@linuxfoundation.org> X-Mailer: git-send-email 2.26.2 In-Reply-To: <20200504165456.783676004@linuxfoundation.org> References: <20200504165456.783676004@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: Al Viro commit 3815f1be546e752327b5868af103ccdddcc4db77 upstream. 'count' is how much you want written, not the final position. Moreover, it can legitimately be less than the current position... Cc: stable@vger.kernel.org Signed-off-by: Al Viro Signed-off-by: Greg Kroah-Hartman --- fs/ocfs2/dlmfs/dlmfs.c | 27 ++++++++++++--------------- 1 file changed, 12 insertions(+), 15 deletions(-) --- a/fs/ocfs2/dlmfs/dlmfs.c +++ b/fs/ocfs2/dlmfs/dlmfs.c @@ -275,7 +275,6 @@ static ssize_t dlmfs_file_write(struct f loff_t *ppos) { int bytes_left; - ssize_t writelen; char *lvb_buf; struct inode *inode = file_inode(filp); @@ -285,32 +284,30 @@ static ssize_t dlmfs_file_write(struct f if (*ppos >= i_size_read(inode)) return -ENOSPC; + /* don't write past the lvb */ + if (count > i_size_read(inode) - *ppos) + count = i_size_read(inode) - *ppos; + if (!count) return 0; if (!access_ok(buf, count)) return -EFAULT; - /* don't write past the lvb */ - if ((count + *ppos) > i_size_read(inode)) - writelen = i_size_read(inode) - *ppos; - else - writelen = count - *ppos; - - lvb_buf = kmalloc(writelen, GFP_NOFS); + lvb_buf = kmalloc(count, GFP_NOFS); if (!lvb_buf) return -ENOMEM; - bytes_left = copy_from_user(lvb_buf, buf, writelen); - writelen -= bytes_left; - if (writelen) - user_dlm_write_lvb(inode, lvb_buf, writelen); + bytes_left = copy_from_user(lvb_buf, buf, count); + count -= bytes_left; + if (count) + user_dlm_write_lvb(inode, lvb_buf, count); kfree(lvb_buf); - *ppos = *ppos + writelen; - mlog(0, "wrote %zd bytes\n", writelen); - return writelen; + *ppos = *ppos + count; + mlog(0, "wrote %zu bytes\n", count); + return count; } static void dlmfs_init_once(void *foo)