From patchwork Sun Oct 21 16:15:30 2018 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "Darrick J. Wong" X-Patchwork-Id: 10650991 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 68B5014E2 for ; Sun, 21 Oct 2018 16:15:44 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 591C3287BE for ; Sun, 21 Oct 2018 16:15:44 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 4CD64287C2; Sun, 21 Oct 2018 16:15:44 +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=-8.0 required=2.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,MAILING_LIST_MULTI,RCVD_IN_DNSWL_HI, UNPARSEABLE_RELAY autolearn=unavailable version=3.3.1 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id CDDE0287BE for ; Sun, 21 Oct 2018 16:15:43 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727987AbeJVAa3 (ORCPT ); Sun, 21 Oct 2018 20:30:29 -0400 Received: from userp2120.oracle.com ([156.151.31.85]:43830 "EHLO userp2120.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727876AbeJVAa2 (ORCPT ); Sun, 21 Oct 2018 20:30:28 -0400 Received: from pps.filterd (userp2120.oracle.com [127.0.0.1]) by userp2120.oracle.com (8.16.0.22/8.16.0.22) with SMTP id w9LGEbqS106972; Sun, 21 Oct 2018 16:15:34 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-2018-07-02; bh=6U76j76igW5rHxBV4yEGa3iiO2lOb5rXvTc2z3yca+w=; b=sJiwqeH4X6gEw0lXCFlzzmk9BQSeC7DC/DPG2XKYEwNDCJumhFYBrMWydRzex27pMbjV 33x0Ux4eT4dk//SgW5BAuGHL0SzHb7Ieb3cx/7m8nngYpjO0Mh1Lc9K4he4z3SDfbPec 4+PgsJ1Hp8eOiOStSKoxD18Hfg0FDZwpMqKYzQfyB3okDiBLJbjGAXINPSCQ9+1yaw50 DOgko2nCl5xsn7L+luOOeqzn/eC1QrxE0hpbwEsTFBthjnOhFv2XBEaHZpnCJj1FsT5A sWMnIlyLSlOrI3NnZUEEfW4PlLGqKBA68JxwtgQVxMnNbp7ZA6SrL5OPF+rtaHBZCyV/ 7Q== Received: from userv0022.oracle.com (userv0022.oracle.com [156.151.31.74]) by userp2120.oracle.com with ESMTP id 2n7w0qaxh1-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Sun, 21 Oct 2018 16:15:34 +0000 Received: from userv0121.oracle.com (userv0121.oracle.com [156.151.31.72]) by userv0022.oracle.com (8.14.4/8.14.4) with ESMTP id w9LGFXqi003693 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Sun, 21 Oct 2018 16:15:33 GMT Received: from abhmp0015.oracle.com (abhmp0015.oracle.com [141.146.116.21]) by userv0121.oracle.com (8.14.4/8.13.8) with ESMTP id w9LGFWng018862; Sun, 21 Oct 2018 16:15:33 GMT Received: from localhost (/10.159.225.70) by default (Oracle Beehive Gateway v4.0) with ESMTP ; Sun, 21 Oct 2018 09:15:32 -0700 Subject: [PATCH 04/28] vfs: strengthen checking of file range inputs to generic_remap_checks From: "Darrick J. Wong" To: david@fromorbit.com, darrick.wong@oracle.com Cc: sandeen@redhat.com, linux-nfs@vger.kernel.org, linux-cifs@vger.kernel.org, Amir Goldstein , linux-unionfs@vger.kernel.org, linux-xfs@vger.kernel.org, linux-mm@kvack.org, linux-btrfs@vger.kernel.org, linux-fsdevel@vger.kernel.org, Christoph Hellwig , ocfs2-devel@oss.oracle.com Date: Sun, 21 Oct 2018 09:15:30 -0700 Message-ID: <154013853068.29026.16132846055457280127.stgit@magnolia> In-Reply-To: <154013850285.29026.16168387526580596209.stgit@magnolia> References: <154013850285.29026.16168387526580596209.stgit@magnolia> User-Agent: StGit/0.17.1-dirty MIME-Version: 1.0 X-Proofpoint-Virus-Version: vendor=nai engine=5900 definitions=9053 signatures=668683 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=8.0.1-1807170000 definitions=main-1810210151 Sender: linux-fsdevel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP From: Darrick J. Wong File range remapping, if allowed to run past the destination file's EOF, is an optimization on a regular file write. Regular file writes that extend the file length are subject to various constraints which are not checked by range cloning. This is a correctness problem because we're never allowed to touch ranges that the page cache can't support (s_maxbytes); we're not supposed to deal with large offsets (MAX_NON_LFS) if O_LARGEFILE isn't set; and we must obey resource limits (RLIMIT_FSIZE). Therefore, add these checks to the new generic_remap_checks function so that we curtail unexpected behavior. Signed-off-by: Darrick J. Wong Reviewed-by: Amir Goldstein Reviewed-by: Christoph Hellwig --- mm/filemap.c | 84 ++++++++++++++++++++++++++++++++++++---------------------- 1 file changed, 52 insertions(+), 32 deletions(-) diff --git a/mm/filemap.c b/mm/filemap.c index 47e6bfd45a91..84b7301e41a0 100644 --- a/mm/filemap.c +++ b/mm/filemap.c @@ -2915,6 +2915,42 @@ struct page *read_cache_page_gfp(struct address_space *mapping, } EXPORT_SYMBOL(read_cache_page_gfp); +/* + * Don't operate on ranges the page cache doesn't support, and don't exceed the + * LFS limits. If pos is under the limit it becomes a short access. If it + * exceeds the limit we return -EFBIG. + */ +static int generic_access_check_limits(struct file *file, loff_t pos, + loff_t *count) +{ + struct inode *inode = file->f_mapping->host; + loff_t max_size = inode->i_sb->s_maxbytes; + + if (!(file->f_flags & O_LARGEFILE)) + max_size = MAX_NON_LFS; + + if (unlikely(pos >= max_size)) + return -EFBIG; + *count = min(*count, max_size - pos); + return 0; +} + +static int generic_write_check_limits(struct file *file, loff_t pos, + loff_t *count) +{ + loff_t limit = rlimit(RLIMIT_FSIZE); + + if (limit != RLIM_INFINITY) { + if (pos >= limit) { + send_sig(SIGXFSZ, current, 0); + return -EFBIG; + } + *count = min(*count, limit - pos); + } + + return generic_access_check_limits(file, pos, count); +} + /* * Performs necessary checks before doing a write * @@ -2926,8 +2962,8 @@ inline ssize_t generic_write_checks(struct kiocb *iocb, struct iov_iter *from) { struct file *file = iocb->ki_filp; struct inode *inode = file->f_mapping->host; - unsigned long limit = rlimit(RLIMIT_FSIZE); - loff_t pos; + loff_t count; + int ret; if (!iov_iter_count(from)) return 0; @@ -2936,40 +2972,15 @@ inline ssize_t generic_write_checks(struct kiocb *iocb, struct iov_iter *from) if (iocb->ki_flags & IOCB_APPEND) iocb->ki_pos = i_size_read(inode); - pos = iocb->ki_pos; - if ((iocb->ki_flags & IOCB_NOWAIT) && !(iocb->ki_flags & IOCB_DIRECT)) return -EINVAL; - if (limit != RLIM_INFINITY) { - if (iocb->ki_pos >= limit) { - send_sig(SIGXFSZ, current, 0); - return -EFBIG; - } - iov_iter_truncate(from, limit - (unsigned long)pos); - } - - /* - * LFS rule - */ - if (unlikely(pos + iov_iter_count(from) > MAX_NON_LFS && - !(file->f_flags & O_LARGEFILE))) { - if (pos >= MAX_NON_LFS) - return -EFBIG; - iov_iter_truncate(from, MAX_NON_LFS - (unsigned long)pos); - } - - /* - * Are we about to exceed the fs block limit ? - * - * If we have written data it becomes a short write. If we have - * exceeded without writing data we send a signal and return EFBIG. - * Linus frestrict idea will clean these up nicely.. - */ - if (unlikely(pos >= inode->i_sb->s_maxbytes)) - return -EFBIG; + count = iov_iter_count(from); + ret = generic_write_check_limits(file, iocb->ki_pos, &count); + if (ret) + return ret; - iov_iter_truncate(from, inode->i_sb->s_maxbytes - pos); + iov_iter_truncate(from, count); return iov_iter_count(from); } EXPORT_SYMBOL(generic_write_checks); @@ -2991,6 +3002,7 @@ int generic_remap_checks(struct file *file_in, loff_t pos_in, uint64_t bcount; loff_t size_in, size_out; loff_t bs = inode_out->i_sb->s_blocksize; + int ret; /* The start of both ranges must be aligned to an fs block. */ if (!IS_ALIGNED(pos_in, bs) || !IS_ALIGNED(pos_out, bs)) @@ -3014,6 +3026,14 @@ int generic_remap_checks(struct file *file_in, loff_t pos_in, return -EINVAL; count = min(count, size_in - (uint64_t)pos_in); + ret = generic_access_check_limits(file_in, pos_in, &count); + if (ret) + return ret; + + ret = generic_write_check_limits(file_out, pos_out, &count); + if (ret) + return ret; + /* * If the user wanted us to link to the infile's EOF, round up to the * next block boundary for this check.