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From: ebiederm@xmission.com (Eric W. Biederman)
To: Alan Jenkins <alan.christopher.jenkins@gmail.com>
Cc: David Howells <dhowells@redhat.com>,
	Al Viro <viro@ZenIV.linux.org.uk>,
	linux-api@vger.kernel.org, torvalds@linux-foundation.org,
	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]
Date: Wed, 17 Oct 2018 09:35:45 -0500	[thread overview]
Message-ID: <87woqgiqta.fsf@xmission.com> (raw)
In-Reply-To: <f6f2553e-f64d-9c26-4290-baf43e5f533b@gmail.com> (Alan Jenkins's message of "Wed, 17 Oct 2018 15:31:26 +0100")

Alan Jenkins <alan.christopher.jenkins@gmail.com> writes:

> On 17/10/2018 14:20, David Howells wrote:
>> David Howells <dhowells@redhat.com> 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
>
>
> I agree.  I'm happy to see this is using the same check as do_remount().
>
>
> * change filesystem flags. dir should be a physical root of filesystem.
> * If you've mounted a non-root directory somewhere and want to do remount
> * on it - tough luck.
> */

Davids check will work for bind mounts as well.  It just won't work it
just won't work for files or subdirectories of some mountpoint.

Eric

>> ---
>> 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)) {
>>

  reply	other threads:[~2018-10-17 14:36 UTC|newest]

Thread overview: 110+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-09-21 16:30 [PATCH 00/34] VFS: Introduce filesystem context [ver #12] David Howells
2018-09-21 16:30 ` David Howells
2018-09-21 16:30 ` David Howells
2018-09-21 16:30 ` [PATCH 01/34] vfs: syscall: Add open_tree(2) to reference or clone a mount " David Howells
2018-10-21 16:41   ` Eric W. Biederman
2018-09-21 16:30 ` [PATCH 02/34] vfs: syscall: Add move_mount(2) to move mounts around " David Howells
2018-09-21 16:30 ` [PATCH 03/34] teach move_mount(2) to work with OPEN_TREE_CLONE " David Howells
2018-10-05 18:24   ` Alan Jenkins
2018-10-07 10:48     ` Alan Jenkins
2018-10-07 19:20       ` Alan Jenkins
2018-10-10 12:36       ` David Howells
2018-10-12 14:22         ` Alan Jenkins
2018-10-12 14:22           ` Alan Jenkins
2018-10-12 14:54         ` David Howells
2018-10-12 14:57           ` Alan Jenkins
2018-10-11  9:17       ` David Howells
2018-10-11 11:48         ` Alan Jenkins
2018-10-11 13:10         ` David Howells
2018-10-11 12:14       ` David Howells
2018-10-11 12:23         ` Alan Jenkins
2018-10-11 15:33       ` David Howells
2018-10-11 18:38         ` Eric W. Biederman
2018-10-11 20:17         ` David Howells
2018-10-13  6:06           ` Al Viro
2018-10-17 17:45       ` Alan Jenkins
2018-10-18 20:09     ` David Howells
2018-10-18 20:58     ` David Howells
2018-10-19 11:57     ` David Howells
2018-10-19 13:37     ` David Howells
2018-10-19 17:35       ` Alan Jenkins
2018-10-19 21:35       ` David Howells
2018-10-19 21:40       ` David Howells
2018-10-19 22:36       ` David Howells
2018-10-20  5:25         ` Al Viro
2018-10-20 11:06         ` Alan Jenkins
2018-10-20 11:48           ` Al Viro
2018-10-20 11:48             ` Al Viro
2018-10-20 12:26             ` Al Viro
2018-10-21  0:40         ` David Howells
2018-10-10 11:56   ` David Howells
2018-10-10 12:31   ` David Howells
2018-10-10 12:39     ` Alan Jenkins
2018-10-10 12:50   ` David Howells
2018-10-10 13:02   ` David Howells
2018-10-10 13:06     ` Alan Jenkins
2018-10-21 16:57   ` Eric W. Biederman
2018-10-23 11:19   ` Alan Jenkins
2018-10-23 16:22     ` Al Viro
2018-09-21 16:30 ` [PATCH 04/34] vfs: Suppress MS_* flag defs within the kernel unless explicitly enabled " David Howells
2018-09-21 16:30 ` [PATCH 05/34] vfs: Introduce the basic header for the new mount API's filesystem context " David Howells
2018-09-21 16:30 ` [PATCH 06/34] vfs: Introduce logging functions " David Howells
2018-09-21 16:31 ` [PATCH 07/34] vfs: Add configuration parser helpers " David Howells
2019-03-14  7:46   ` Geert Uytterhoeven
2019-03-14 10:27   ` David Howells
2019-03-14 10:49     ` Geert Uytterhoeven
2018-09-21 16:31 ` [PATCH 08/34] vfs: Add LSM hooks for the new mount API " David Howells
2018-09-21 16:31   ` David Howells
2018-09-21 16:31 ` [PATCH 09/34] vfs: Put security flags into the fs_context struct " David Howells
2018-09-21 16:31 ` [PATCH 10/34] selinux: Implement the new mount API LSM hooks " David Howells
2018-09-21 16:31   ` David Howells
2018-09-21 16:31 ` [PATCH 11/34] smack: Implement filesystem context security " David Howells
2018-09-21 16:31   ` David Howells
2018-09-21 16:31 ` [PATCH 12/34] apparmor: Implement security hooks for the new mount API " David Howells
2018-09-21 16:31   ` David Howells
2018-09-21 16:31 ` [PATCH 13/34] tomoyo: " David Howells
2018-09-21 16:31   ` David Howells
2018-09-21 16:32 ` [PATCH 14/34] vfs: Separate changing mount flags full remount " David Howells
2018-09-21 16:32 ` [PATCH 15/34] vfs: Implement a filesystem superblock creation/configuration context " David Howells
2018-09-21 16:32 ` [PATCH 16/34] vfs: Remove unused code after filesystem context changes " David Howells
2018-09-21 16:32 ` [PATCH 17/34] procfs: Move proc_fill_super() to fs/proc/root.c " David Howells
2018-09-21 16:32 ` [PATCH 18/34] proc: Add fs_context support to procfs " David Howells
2018-09-21 16:32 ` [PATCH 19/34] ipc: Convert mqueue fs to fs_context " David Howells
2018-09-21 16:32 ` [PATCH 20/34] cpuset: Use " David Howells
2018-09-21 16:33 ` [PATCH 21/34] kernfs, sysfs, cgroup, intel_rdt: Support " David Howells
2018-11-19  4:23   ` Andrei Vagin
2018-12-06 17:08     ` Andrei Vagin
2018-09-21 16:33 ` [PATCH 22/34] hugetlbfs: Convert to " David Howells
2018-09-21 16:33 ` [PATCH 23/34] vfs: Remove kern_mount_data() " David Howells
2018-09-21 16:33 ` [PATCH 24/34] vfs: Provide documentation for new mount API " David Howells
2018-09-21 16:33 ` [PATCH 25/34] Make anon_inodes unconditional " David Howells
2018-09-21 16:33 ` [PATCH 26/34] vfs: syscall: Add fsopen() to prepare for superblock creation " David Howells
2018-09-21 16:33 ` [PATCH 27/34] vfs: Implement logging through fs_context " David Howells
2018-09-21 16:33 ` [PATCH 28/34] vfs: Add some logging to the core users of the fs_context log " David Howells
2018-09-21 16:34 ` [PATCH 29/34] vfs: syscall: Add fsconfig() for configuring and managing a context " David Howells
2018-09-21 16:34 ` [PATCH 30/34] vfs: syscall: Add fsmount() to create a mount for a superblock " David Howells
2018-09-21 16:34 ` [PATCH 31/34] vfs: syscall: Add fspick() to select a superblock for reconfiguration " David Howells
2018-10-12 14:49   ` Alan Jenkins
2018-10-13  6:11     ` Al Viro
2018-10-13  6:11       ` Al Viro
2018-10-13  9:45       ` Alan Jenkins
2018-10-13 23:04         ` Andy Lutomirski
2018-10-17 13:15       ` David Howells
2018-10-17 13:20       ` David Howells
2018-10-17 13:20         ` David Howells
2018-10-17 14:31         ` Alan Jenkins
2018-10-17 14:35           ` Eric W. Biederman [this message]
2018-10-17 14:55             ` Alan Jenkins
2018-10-17 15:24           ` David Howells
2018-10-17 15:24             ` David Howells
2018-10-17 15:38             ` Eric W. Biederman
2018-10-17 15:45         ` David Howells
2018-10-17 17:41           ` Alan Jenkins
2018-10-17 21:20           ` David Howells
2018-10-17 22:13           ` Alan Jenkins
2018-09-21 16:34 ` [PATCH 32/34] afs: Add fs_context support " David Howells
2018-09-21 16:34 ` [PATCH 33/34] afs: Use fs_context to pass parameters over automount " David Howells
2018-09-21 16:34 ` [PATCH 34/34] vfs: Add a sample program for the new mount API " David Howells
2018-12-17 14:12   ` Anders Roxell
2018-12-20 16:36   ` David Howells
2018-10-04 18:37 ` [PATCH 00/34] VFS: Introduce filesystem context " Eric W. Biederman

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