From patchwork Fri Jun 21 23:56:58 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "Darrick J. Wong" X-Patchwork-Id: 11010885 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 9D28376 for ; Fri, 21 Jun 2019 23:58:04 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 8E42528BAF for ; Fri, 21 Jun 2019 23:58:04 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 8275228BB5; Fri, 21 Jun 2019 23:58:04 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-5.3 required=2.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,MAILING_LIST_MULTI,RCVD_IN_DNSWL_MED, UNPARSEABLE_RELAY autolearn=unavailable version=3.3.1 Received: from userp2130.oracle.com (userp2130.oracle.com [156.151.31.86]) (using TLSv1.2 with cipher AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.wl.linuxfoundation.org (Postfix) with ESMTPS id 152F228BAF for ; Fri, 21 Jun 2019 23:58:03 +0000 (UTC) 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 x5LNt3Pa052786; Fri, 21 Jun 2019 23:57:41 GMT DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=oracle.com; h=from : to : date : message-id : in-reply-to : references : mime-version : cc : subject : list-id : list-unsubscribe : list-archive : list-post : list-help : list-subscribe : content-type : content-transfer-encoding : sender; s=corp-2018-07-02; bh=JDGjr7pdl0j1KEMiwziERzU6pPymVBdLRXXlPsum6zM=; b=ZgUGmgcSNrtcRKQZ7W9QCOZzINOQf5qvdEKurt1kcZpGCHCciI4TwJcgDboSt8qjBraa YLj+vvIgQQmETUHhPQlr08CqJZcRTjkEI8hPxxYlEAuel50pEzjBx/4Xkn2KdRDUetqe chNnBlGb+eHhaIaRJ4vKhxruutUOAvpaccl3XsNj8MWOTP6aSMK10VKfAkAXjg0xXRpo uLP7aRPD1o36avFMMME+d5JexHqBX7t8hZJQLrJc44xKynQAHn9KJSqeCpFSuJz97l6H bfWD03JszLzWclV75UxARogOJDTjdui3spkYgrQhrcx9jcqYPyEA7vhbhQ+VHtVF9l1K Sg== Received: from userv0021.oracle.com (userv0021.oracle.com [156.151.31.71]) by userp2130.oracle.com with ESMTP id 2t7809rsxp-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Fri, 21 Jun 2019 23:57:41 +0000 Received: from oss.oracle.com (oss-old-reserved.oracle.com [137.254.22.2]) by userv0021.oracle.com (8.14.4/8.14.4) with ESMTP id x5LNve6G026369 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=NO); Fri, 21 Jun 2019 23:57:40 GMT Received: from localhost ([127.0.0.1] helo=lb-oss.oracle.com) by oss.oracle.com with esmtp (Exim 4.63) (envelope-from ) id 1heTPY-0001Lu-DV; Fri, 21 Jun 2019 16:57:40 -0700 Received: from aserp3030.oracle.com ([141.146.126.71]) by oss.oracle.com with esmtp (Exim 4.63) (envelope-from ) id 1heTOy-0001Dc-U9 for ocfs2-devel@oss.oracle.com; Fri, 21 Jun 2019 16:57:04 -0700 Received: from pps.filterd (aserp3030.oracle.com [127.0.0.1]) by aserp3030.oracle.com (8.16.0.27/8.16.0.27) with SMTP id x5LNtK7M167990 for ; Fri, 21 Jun 2019 23:57:04 GMT Authentication-Results: aserp3010.oracle.com; spf=pass smtp.mailfrom=darrick.wong@oracle.com; dmarc=pass header.from=oracle.com Received: from pps.reinject (localhost [127.0.0.1]) by aserp3030.oracle.com with ESMTP id 2t7rdy0611-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=FAIL) for ; Fri, 21 Jun 2019 23:57:04 +0000 Received: from aserp3030.oracle.com (aserp3030.oracle.com [127.0.0.1]) by pps.reinject (8.16.0.27/8.16.0.27) with SMTP id x5LNuhUv170079 for ; Fri, 21 Jun 2019 23:57:04 GMT Received: from userv0122.oracle.com (userv0122.oracle.com [156.151.31.75]) by aserp3030.oracle.com with ESMTP id 2t7rdy060u-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Fri, 21 Jun 2019 23:57:04 +0000 Received: from abhmp0004.oracle.com (abhmp0004.oracle.com [141.146.116.10]) by userv0122.oracle.com (8.14.4/8.14.4) with ESMTP id x5LNv2Il019145; Fri, 21 Jun 2019 23:57:02 GMT Received: from localhost (/10.159.131.214) by default (Oracle Beehive Gateway v4.0) with ESMTP ; Fri, 21 Jun 2019 16:57:02 -0700 From: "Darrick J. Wong" To: matthew.garrett@nebula.com, yuchao0@huawei.com, tytso@mit.edu, darrick.wong@oracle.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 Date: Fri, 21 Jun 2019 16:56:58 -0700 Message-ID: <156116141836.1664939.12249697737780481978.stgit@magnolia> In-Reply-To: <156116141046.1664939.11424021489724835645.stgit@magnolia> References: <156116141046.1664939.11424021489724835645.stgit@magnolia> User-Agent: StGit/0.17.1-dirty MIME-Version: 1.0 Cc: linux-efi@vger.kernel.org, linux-btrfs@vger.kernel.org, linux-kernel@vger.kernel.org, reiserfs-devel@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, devel@lists.orangefs.org Subject: [Ocfs2-devel] [PATCH 1/7] mm/fs: don't allow writes to immutable files X-BeenThere: ocfs2-devel@oss.oracle.com X-Mailman-Version: 2.1.9 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: ocfs2-devel-bounces@oss.oracle.com Errors-To: ocfs2-devel-bounces@oss.oracle.com X-Proofpoint-Virus-Version: vendor=nai engine=6000 definitions=9295 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=761 adultscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1810050000 definitions=main-1906210182 X-Virus-Scanned: ClamAV using ClamSMTP 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 Reviewed-by: Jan Kara --- fs/attr.c | 13 ++++++------- mm/filemap.c | 3 +++ mm/memory.c | 3 +++ mm/mmap.c | 8 ++++++-- 4 files changed, 18 insertions(+), 9 deletions(-) diff --git a/fs/attr.c b/fs/attr.c index d22e8187477f..1fcfdcc5b367 100644 --- a/fs/attr.c +++ b/fs/attr.c @@ -233,19 +233,18 @@ int notify_change(struct dentry * dentry, struct iattr * attr, struct inode **de WARN_ON_ONCE(!inode_is_locked(inode)); - if (ia_valid & (ATTR_MODE | ATTR_UID | ATTR_GID | ATTR_TIMES_SET)) { - if (IS_IMMUTABLE(inode) || IS_APPEND(inode)) - return -EPERM; - } + if (IS_IMMUTABLE(inode)) + return -EPERM; + + if ((ia_valid & (ATTR_MODE | ATTR_UID | ATTR_GID | ATTR_TIMES_SET)) && + IS_APPEND(inode)) + return -EPERM; /* * If utimes(2) and friends are called with times == NULL (or both * times are UTIME_NOW), then we need to check for write permission */ if (ia_valid & ATTR_TOUCH) { - if (IS_IMMUTABLE(inode)) - return -EPERM; - if (!inode_owner_or_capable(inode)) { error = inode_permission(inode, MAY_WRITE); if (error) diff --git a/mm/filemap.c b/mm/filemap.c index aac71aef4c61..dad85e10f5f8 100644 --- a/mm/filemap.c +++ b/mm/filemap.c @@ -2935,6 +2935,9 @@ inline ssize_t generic_write_checks(struct kiocb *iocb, struct iov_iter *from) loff_t count; int ret; + if (IS_IMMUTABLE(inode)) + return -EPERM; + if (!iov_iter_count(from)) return 0; diff --git a/mm/memory.c b/mm/memory.c index ddf20bd0c317..4311cfdade90 100644 --- a/mm/memory.c +++ b/mm/memory.c @@ -2235,6 +2235,9 @@ static vm_fault_t do_page_mkwrite(struct vm_fault *vmf) vmf->flags = FAULT_FLAG_WRITE|FAULT_FLAG_MKWRITE; + if (vmf->vma->vm_file && IS_IMMUTABLE(file_inode(vmf->vma->vm_file))) + return VM_FAULT_SIGBUS; + ret = vmf->vma->vm_ops->page_mkwrite(vmf); /* Restore original flags so that caller is not surprised */ vmf->flags = old_flags; diff --git a/mm/mmap.c b/mm/mmap.c index 7e8c3e8ae75f..ac1e32205237 100644 --- a/mm/mmap.c +++ b/mm/mmap.c @@ -1483,8 +1483,12 @@ unsigned long do_mmap(struct file *file, unsigned long addr, case MAP_SHARED_VALIDATE: if (flags & ~flags_mask) return -EOPNOTSUPP; - if ((prot&PROT_WRITE) && !(file->f_mode&FMODE_WRITE)) - return -EACCES; + if (prot & PROT_WRITE) { + if (!(file->f_mode & FMODE_WRITE)) + return -EACCES; + if (IS_IMMUTABLE(file_inode(file))) + return -EPERM; + } /* * Make sure we don't allow writing to an append-only