From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mx1.redhat.com ([209.132.183.28]:47664 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726974AbeJQVP5 (ORCPT ); Wed, 17 Oct 2018 17:15:57 -0400 From: David Howells In-Reply-To: <19866.1539782101@warthog.procyon.org.uk> References: <19866.1539782101@warthog.procyon.org.uk> <68a2107f-bf70-055b-86cf-1ba2ba9422bf@gmail.com> <153754740781.17872.7869536526927736855.stgit@warthog.procyon.org.uk> <153754766004.17872.9829232103614083565.stgit@warthog.procyon.org.uk> <9b8bf436-65de-13b9-0002-0479d11c18ca@gmail.com> <20181013061141.GR32577@ZenIV.linux.org.uk> Cc: dhowells@redhat.com, Alan Jenkins , Al Viro , linux-api@vger.kernel.org, torvalds@linux-foundation.org, ebiederm@xmission.com, linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, mszeredi@redhat.com Subject: Re: [PATCH 31/34] vfs: syscall: Add fspick() to select a superblock for reconfiguration [ver #12] MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-ID: <28709.1539782412.1@warthog.procyon.org.uk> Content-Transfer-Encoding: 8BIT Date: Wed, 17 Oct 2018 14:20:12 +0100 Message-ID: <28710.1539782412@warthog.procyon.org.uk> To: unlisted-recipients:; (no To-header on input) Sender: linux-fsdevel-owner@vger.kernel.org List-ID: David Howells wrote: > I should probably check that the picked point is actually a mountpoint. The root of the mount object at the path specified, that is, perhaps with something like the attached. David --- diff --git a/fs/fsopen.c b/fs/fsopen.c index f673e93ac456..aaaaa17a233c 100644 --- a/fs/fsopen.c +++ b/fs/fsopen.c @@ -186,6 +186,10 @@ SYSCALL_DEFINE3(fspick, int, dfd, const char __user *, path, unsigned int, flags if (ret < 0) goto err; + ret = -EINVAL; + if (target.mnt->mnt_root != target.dentry) + goto err_path; + fc = vfs_new_fs_context(target.dentry->d_sb->s_type, target.dentry, 0, 0, FS_CONTEXT_FOR_RECONFIGURE); if (IS_ERR(fc)) {