From patchwork Thu Aug 15 16:05:56 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: 11095971 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 49EA06C5 for ; Thu, 15 Aug 2019 16:06:18 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 3843520501 for ; Thu, 15 Aug 2019 16:06:18 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 363A028995; Thu, 15 Aug 2019 16:06:18 +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=-3.0 required=2.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,MAILING_LIST_MULTI,RCVD_IN_DNSWL_NONE, UNPARSEABLE_RELAY autolearn=ham version=3.3.1 Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 75CE1288C3 for ; Thu, 15 Aug 2019 16:06:17 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 8F6FC6B02B7; Thu, 15 Aug 2019 12:06:16 -0400 (EDT) Delivered-To: linux-mm-outgoing@kvack.org Received: by kanga.kvack.org (Postfix, from userid 40) id 8A7236B02B8; Thu, 15 Aug 2019 12:06:16 -0400 (EDT) X-Original-To: int-list-linux-mm@kvack.org X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 795826B02B9; Thu, 15 Aug 2019 12:06:16 -0400 (EDT) X-Original-To: linux-mm@kvack.org X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0020.hostedemail.com [216.40.44.20]) by kanga.kvack.org (Postfix) with ESMTP id 522E96B02B7 for ; Thu, 15 Aug 2019 12:06:16 -0400 (EDT) Received: from smtpin21.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay04.hostedemail.com (Postfix) with SMTP id ED50E68A7 for ; Thu, 15 Aug 2019 16:06:15 +0000 (UTC) X-FDA: 75825139110.21.sun10_1984c21563e0c X-HE-Tag: sun10_1984c21563e0c X-Filterd-Recvd-Size: 6718 Received: from aserp2120.oracle.com (aserp2120.oracle.com [141.146.126.78]) by imf43.hostedemail.com (Postfix) with ESMTP for ; Thu, 15 Aug 2019 16:06:15 +0000 (UTC) Received: from pps.filterd (aserp2120.oracle.com [127.0.0.1]) by aserp2120.oracle.com (8.16.0.27/8.16.0.27) with SMTP id x7FG3sVD003017; Thu, 15 Aug 2019 16:06:06 GMT DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=oracle.com; h=subject : from : to : cc : date : message-id : in-reply-to : references : mime-version : content-type : content-transfer-encoding; s=corp-2019-08-05; bh=VP7sCuMn0gxFRzE/Z9kn9dLvV5aSB5uEzEdCLBDAUN0=; b=g8Wp22RcUI/HyKFOJzzL++o/Q50ury1Dgif2c3GyYrt/ptsNkEtihQkvPOC/ZyoleOl2 GBbOKD22/A9RvP0XzO2QzX0KwfaGMljHqaxHIqxWDDnfuEYmv9jJrWyoMeP6Ltgk28M2 F6//Uz4RETgbhY+qUHobUQeNDoNOxiaERb/a7qgmFqb110dPSgrMh+GIj0LnT4HXq7kB nIXOLQsPQamu7WDJ06qPYYlGbSDZbB8Z3ZZV0fgw5VtgayPybYlZTXS6WvikWtaBhKR9 yUxhefgNndcfkNReJ4+TIK8szOsIe+Bj7dm5ThPa0JE6EB5eQkosOl+IkyzK86KWdNrp CA== Received: from aserp3020.oracle.com (aserp3020.oracle.com [141.146.126.70]) by aserp2120.oracle.com with ESMTP id 2u9nvpkp4d-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Thu, 15 Aug 2019 16:06:06 +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 x7FG30Qd054300; Thu, 15 Aug 2019 16:06:05 GMT Received: from userv0122.oracle.com (userv0122.oracle.com [156.151.31.75]) by aserp3020.oracle.com with ESMTP id 2ucpysg627-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Thu, 15 Aug 2019 16:06:05 +0000 Received: from abhmp0008.oracle.com (abhmp0008.oracle.com [141.146.116.14]) by userv0122.oracle.com (8.14.4/8.14.4) with ESMTP id x7FG64Jb002753; Thu, 15 Aug 2019 16:06:04 GMT Received: from localhost (/67.169.218.210) by default (Oracle Beehive Gateway v4.0) with ESMTP ; Thu, 15 Aug 2019 09:06:03 -0700 Subject: [PATCH 2/2] vfs: don't allow writes to swap files From: "Darrick J. Wong" To: hch@infradead.org, akpm@linux-foundation.org, tytso@mit.edu, viro@zeniv.linux.org.uk, darrick.wong@oracle.com Cc: linux-xfs@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org Date: Thu, 15 Aug 2019 09:05:56 -0700 Message-ID: <156588515613.111054.13578448017133006248.stgit@magnolia> In-Reply-To: <156588514105.111054.13645634739408399209.stgit@magnolia> References: <156588514105.111054.13645634739408399209.stgit@magnolia> User-Agent: StGit/0.17.1-dirty MIME-Version: 1.0 X-Proofpoint-Virus-Version: vendor=nai engine=6000 definitions=9350 signatures=668684 X-Proofpoint-Spam-Details: rule=notspam policy=default score=0 suspectscore=0 malwarescore=0 phishscore=0 bulkscore=0 spamscore=0 mlxscore=0 mlxlogscore=999 adultscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1906280000 definitions=main-1908150157 X-Proofpoint-Virus-Version: vendor=nai engine=6000 definitions=9350 signatures=668684 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=999 adultscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1906280000 definitions=main-1908150158 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: X-Virus-Scanned: ClamAV using ClamSMTP From: Darrick J. Wong Don't let userspace write to an active swap file because the kernel effectively has a long term lease on the storage and things could get seriously corrupted if we let this happen. Signed-off-by: Darrick J. Wong --- fs/block_dev.c | 3 +++ mm/filemap.c | 3 +++ mm/memory.c | 4 ++++ mm/mmap.c | 8 ++++++-- mm/swapfile.c | 12 +++++++++++- 5 files changed, 27 insertions(+), 3 deletions(-) diff --git a/fs/block_dev.c b/fs/block_dev.c index eb657ab94060..017f46719ebe 100644 --- a/fs/block_dev.c +++ b/fs/block_dev.c @@ -2011,6 +2011,9 @@ ssize_t blkdev_write_iter(struct kiocb *iocb, struct iov_iter *from) if (bdev_read_only(I_BDEV(bd_inode))) return -EPERM; + if (IS_SWAPFILE(bd_inode)) + return -ETXTBSY; + if (!iov_iter_count(from)) return 0; diff --git a/mm/filemap.c b/mm/filemap.c index d0cf700bf201..40667c2f3383 100644 --- a/mm/filemap.c +++ b/mm/filemap.c @@ -2988,6 +2988,9 @@ inline ssize_t generic_write_checks(struct kiocb *iocb, struct iov_iter *from) loff_t count; int ret; + if (IS_SWAPFILE(inode)) + return -ETXTBSY; + if (!iov_iter_count(from)) return 0; diff --git a/mm/memory.c b/mm/memory.c index e2bb51b6242e..b1dff75640b7 100644 --- a/mm/memory.c +++ b/mm/memory.c @@ -2196,6 +2196,10 @@ 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_SWAPFILE(vmf->vma->vm_file->f_mapping->host)) + 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..6bc21fca20bc 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_SWAPFILE(file->f_mapping->host)) + return -ETXTBSY; + } /* * Make sure we don't allow writing to an append-only diff --git a/mm/swapfile.c b/mm/swapfile.c index a53b7c49b40e..dab43523afdd 100644 --- a/mm/swapfile.c +++ b/mm/swapfile.c @@ -3275,6 +3275,17 @@ SYSCALL_DEFINE2(swapon, const char __user *, specialfile, int, swap_flags) if (error) goto bad_swap; + /* + * Flush any pending IO and dirty mappings before we start using this + * swap device. + */ + inode->i_flags |= S_SWAPFILE; + error = inode_drain_writes(inode); + if (error) { + inode->i_flags &= ~S_SWAPFILE; + goto bad_swap; + } + mutex_lock(&swapon_mutex); prio = -1; if (swap_flags & SWAP_FLAG_PREFER) @@ -3295,7 +3306,6 @@ SYSCALL_DEFINE2(swapon, const char __user *, specialfile, int, swap_flags) atomic_inc(&proc_poll_event); wake_up_interruptible(&proc_poll_wait); - inode->i_flags |= S_SWAPFILE; error = 0; goto out; bad_swap: