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=-5.3 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,UNPARSEABLE_RELAY,USER_AGENT_MUTT 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 E8EFAC43613 for ; Thu, 20 Jun 2019 22:14:23 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id BC11B2070B for ; Thu, 20 Jun 2019 22:14:23 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=oracle.com header.i=@oracle.com header.b="HRHy43z6" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726412AbfFTWOX (ORCPT ); Thu, 20 Jun 2019 18:14:23 -0400 Received: from userp2130.oracle.com ([156.151.31.86]:35672 "EHLO userp2130.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725906AbfFTWOX (ORCPT ); Thu, 20 Jun 2019 18:14:23 -0400 Received: from pps.filterd (userp2130.oracle.com [127.0.0.1]) by userp2130.oracle.com (8.16.0.27/8.16.0.27) with SMTP id x5KM3nsv109072; Thu, 20 Jun 2019 22:13:13 GMT DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=oracle.com; h=date : from : to : subject : message-id : references : mime-version : content-type : in-reply-to; s=corp-2018-07-02; bh=OsSBTvuyKOZHpYxr7BMRKlrDJF74SMWishCpQlewDkg=; b=HRHy43z65mymGGo6sWVVPuVFpItbR12cz3YFYbaCqJGOBgvqYtfpb/PeLVjuuEVqrQv2 GpZIrIgzJZC0+U+yXwJ1Vqs3qY3UMIfqSIwL3pZPIfdyZff3jwYOEkEcKtjd/YwH/Sq6 aV/5TlsmcdKu7KhrpVNfWRmjrbQlir4Di4CKy0hExq7FpxJJYc99Sw4feLIcaNKWlvrK 5xy4bURhqhJGb38LoU38YZ1npKwLTXMnl7fXFWWSALJ4esecgPStCOfTzz7/fuGUuQ5/ 3Ls5Aj1t1c7iY5R0EC3GWYb2yjGGpkr0/0/gtaJLRnwOzAdzATduot/C0pAUHfoTLX0u QQ== Received: from aserp3020.oracle.com (aserp3020.oracle.com [141.146.126.70]) by userp2130.oracle.com with ESMTP id 2t7809kgm8-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Thu, 20 Jun 2019 22:13:13 +0000 Received: from pps.filterd (aserp3020.oracle.com [127.0.0.1]) by aserp3020.oracle.com (8.16.0.27/8.16.0.27) with SMTP id x5KMCXI6043214; Thu, 20 Jun 2019 22:13:12 GMT Received: from pps.reinject (localhost [127.0.0.1]) by aserp3020.oracle.com with ESMTP id 2t77ypm9eb-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=FAIL); Thu, 20 Jun 2019 22:13:12 +0000 Received: from aserp3020.oracle.com (aserp3020.oracle.com [127.0.0.1]) by pps.reinject (8.16.0.27/8.16.0.27) with SMTP id x5KMDCTk044443; Thu, 20 Jun 2019 22:13:12 GMT Received: from userv0122.oracle.com (userv0122.oracle.com [156.151.31.75]) by aserp3020.oracle.com with ESMTP id 2t77ypm9e2-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Thu, 20 Jun 2019 22:13:12 +0000 Received: from abhmp0019.oracle.com (abhmp0019.oracle.com [141.146.116.25]) by userv0122.oracle.com (8.14.4/8.14.4) with ESMTP id x5KMD85F022773; Thu, 20 Jun 2019 22:13:09 GMT Received: from localhost (/10.145.179.81) by default (Oracle Beehive Gateway v4.0) with ESMTP ; Thu, 20 Jun 2019 15:13:08 -0700 Date: Thu, 20 Jun 2019 15:13:06 -0700 From: "Darrick J. Wong" To: "Theodore Ts'o" , matthew.garrett@nebula.com, yuchao0@huawei.com, ard.biesheuvel@linaro.org, josef@toxicpanda.com, clm@fb.com, adilger.kernel@dilger.ca, viro@zeniv.linux.org.uk, jack@suse.com, dsterba@suse.com, jaegeuk@kernel.org, jk@ozlabs.org, reiserfs-devel@vger.kernel.org, linux-efi@vger.kernel.org, devel@lists.orangefs.org, linux-kernel@vger.kernel.org, linux-f2fs-devel@lists.sourceforge.net, linux-xfs@vger.kernel.org, linux-mm@kvack.org, linux-nilfs@vger.kernel.org, linux-mtd@lists.infradead.org, ocfs2-devel@oss.oracle.com, linux-fsdevel@vger.kernel.org, linux-ext4@vger.kernel.org, linux-btrfs@vger.kernel.org Subject: Re: [PATCH 1/6] mm/fs: don't allow writes to immutable files Message-ID: <20190620221306.GD5375@magnolia> References: <156022836912.3227213.13598042497272336695.stgit@magnolia> <156022837711.3227213.11787906519006016743.stgit@magnolia> <20190620215212.GG4650@mit.edu> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20190620215212.GG4650@mit.edu> User-Agent: Mutt/1.9.4 (2018-02-28) X-Proofpoint-Virus-Version: vendor=nai engine=6000 definitions=9294 signatures=668687 X-Proofpoint-Spam-Details: rule=notspam policy=default score=0 priorityscore=1501 malwarescore=0 suspectscore=0 phishscore=0 bulkscore=0 spamscore=0 clxscore=1015 lowpriorityscore=0 mlxscore=0 impostorscore=0 mlxlogscore=570 adultscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1810050000 definitions=main-1906200158 Sender: linux-efi-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-efi@vger.kernel.org On Thu, Jun 20, 2019 at 05:52:12PM -0400, Theodore Ts'o wrote: > On Mon, Jun 10, 2019 at 09:46:17PM -0700, Darrick J. Wong wrote: > > From: Darrick J. Wong > > > > The chattr manpage has this to say about immutable files: > > > > "A file with the 'i' attribute cannot be modified: it cannot be deleted > > or renamed, no link can be created to this file, most of the file's > > metadata can not be modified, and the file can not be opened in write > > mode." > > > > Once the flag is set, it is enforced for quite a few file operations, > > such as fallocate, fpunch, fzero, rm, touch, open, etc. However, we > > don't check for immutability when doing a write(), a PROT_WRITE mmap(), > > a truncate(), or a write to a previously established mmap. > > > > If a program has an open write fd to a file that the administrator > > subsequently marks immutable, the program still can change the file > > contents. Weird! > > > > The ability to write to an immutable file does not follow the manpage > > promise that immutable files cannot be modified. Worse yet it's > > inconsistent with the behavior of other syscalls which don't allow > > modifications of immutable files. > > > > Therefore, add the necessary checks to make the write, mmap, and > > truncate behavior consistent with what the manpage says and consistent > > with other syscalls on filesystems which support IMMUTABLE. > > > > Signed-off-by: Darrick J. Wong > > I note that this patch doesn't allow writes to swap files. So Amir's > generic/554 test will still fail for those file systems that don't use > copy_file_range. I didn't add any IS_SWAPFILE checks here, so I'm not sure to what you're referring? > I'm indifferent as to whether you add a new patch, or include that > change in this patch, but perhaps we should fix this while we're > making changes in these code paths? The swapfile patches should be in a separate patch, which I was planning to work on but hadn't really gotten around to it. --D > - Ted