From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pl1-f199.google.com (mail-pl1-f199.google.com [209.85.214.199]) by kanga.kvack.org (Postfix) with ESMTP id 8759B6B0269 for ; Tue, 9 Oct 2018 20:11:11 -0400 (EDT) Received: by mail-pl1-f199.google.com with SMTP id f5-v6so2630943plf.11 for ; Tue, 09 Oct 2018 17:11:11 -0700 (PDT) Received: from userp2130.oracle.com (userp2130.oracle.com. [156.151.31.86]) by mx.google.com with ESMTPS id z1-v6si22516285plo.59.2018.10.09.17.11.10 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Tue, 09 Oct 2018 17:11:10 -0700 (PDT) Subject: [PATCH 04/25] xfs: update ctime and remove suid before cloning files From: "Darrick J. Wong" Date: Tue, 09 Oct 2018 17:11:06 -0700 Message-ID: <153913026644.32295.612141018276176517.stgit@magnolia> In-Reply-To: <153913023835.32295.13962696655740190941.stgit@magnolia> References: <153913023835.32295.13962696655740190941.stgit@magnolia> MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org List-ID: To: david@fromorbit.com, darrick.wong@oracle.com Cc: sandeen@redhat.com, linux-nfs@vger.kernel.org, linux-cifs@vger.kernel.org, linux-unionfs@vger.kernel.org, linux-xfs@vger.kernel.org, linux-mm@kvack.org, linux-btrfs@vger.kernel.org, Dave Chinner , linux-fsdevel@vger.kernel.org, ocfs2-devel@oss.oracle.com From: Darrick J. Wong Before cloning into a file, update the ctime and remove sensitive attributes like suid, just like we'd do for a regular file write. Signed-off-by: Darrick J. Wong Reviewed-by: Dave Chinner --- fs/xfs/xfs_reflink.c | 25 +++++++++++++++++++++++++ 1 file changed, 25 insertions(+) diff --git a/fs/xfs/xfs_reflink.c b/fs/xfs/xfs_reflink.c index cbb359e68a72..d4feaeba8542 100644 --- a/fs/xfs/xfs_reflink.c +++ b/fs/xfs/xfs_reflink.c @@ -1264,6 +1264,7 @@ xfs_reflink_zero_posteof( * Prepare two files for range cloning. Upon a successful return both inodes * will have the iolock and mmaplock held, the page cache of the out file * will be truncated, and any leases on the out file will have been broken. + * This function borrows heavily from xfs_file_aio_write_checks. * Returns negative for error, 0 for nothing to do, and 1 for success. */ STATIC int @@ -1328,6 +1329,30 @@ xfs_reflink_remap_prep( /* Zap any page cache for the destination file's range. */ truncate_inode_pages_range(&inode_out->i_data, pos_out, PAGE_ALIGN(pos_out + *len) - 1); + + /* If we're altering the file contents... */ + if (!is_dedupe) { + /* + * ...update the timestamps (which will grab the ilock again + * from xfs_fs_dirty_inode, so we have to call it before we + * take the ilock). + */ + if (!(file_out->f_mode & FMODE_NOCMTIME)) { + ret = file_update_time(file_out); + if (ret) + goto out_unlock; + } + + /* + * ...clear the security bits if the process is not being run + * by root. This keeps people from modifying setuid and setgid + * binaries. + */ + ret = file_remove_privs(file_out); + if (ret) + goto out_unlock; + } + return 1; out_unlock: xfs_reflink_remap_unlock(file_in, file_out);