From: Pavel Machek <pavel@suse.cz>
To: Trond Myklebust <trond.myklebust@fys.uio.no>
Cc: Jan Kara <jack@suse.cz>, Josef Sipek <jsipek@fsl.cs.sunysb.edu>,
Andrew Morton <akpm@osdl.org>,
linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org,
hch@infradead.org, viro@ftp.linux.org.uk, torvalds@osdl.org,
mhalcrow@us.ibm.com, David Quigley <dquigley@fsl.cs.sunysb.edu>,
Erez Zadok <ezk@cs.sunysb.edu>
Subject: unionfs unusable on multiuser systems (was Re: [PATCH 01/24] Unionfs: Documentation)
Date: Thu, 11 Jan 2007 14:29:56 +0000 [thread overview]
Message-ID: <20070111142956.GA6843@ucw.cz> (raw)
In-Reply-To: <1168360219.6054.14.camel@lade.trondhjem.org>
Hi!
> > > That statement is meant to scare people away from modifying the lower fs :)
> > > I tortured unionfs quite a bit, and it can oops but it takes some effort.
> > But isn't it then potential DOS? If you happen to union two filesystems
> > and an untrusted user has write access to both original filesystem and
> > the union, then you say he'd be able to produce oops? That does not
> > sound very secure to me... And if any secure use of unionfs requires
> > limitting access to the original trees, then I think it's a good reason
> > to implement it in unionfs itself. Just my 2 cents.
>
> You mean somebody like, say, a perfectly innocent process working on the
> NFS server or some other client that is oblivious to the existence of
> unionfs stacks on your particular machine?
> To me, this has always sounded like a showstopper for using unionfs with
> a remote filesystem.
Actually, it is worse than that. find / (and updatedb) *will* write to
all the filesystems (atime).
Expecting sysadmins to know/prevent this seems like expecting quite a
lot from them. Sounds like a show stopper to me :-(....
Pavel
--
Thanks for all the (sleeping) penguins.
next prev parent reply other threads:[~2007-01-12 11:02 UTC|newest]
Thread overview: 82+ messages / expand[flat|nested] mbox.gz Atom feed top
2007-01-08 4:12 [PATCH 00/24] Unionfs, try #4 Josef 'Jeff' Sipek
2007-01-08 4:12 ` [PATCH 01/24] Unionfs: Documentation Josef 'Jeff' Sipek
2007-01-08 19:18 ` Andrew Morton
2007-01-08 19:43 ` Shaya Potter
2007-01-08 20:24 ` Jan Engelhardt
2007-01-08 21:32 ` Shaya Potter
2007-01-08 21:19 ` Andrew Morton
2007-01-08 21:30 ` Shaya Potter
2007-01-08 22:02 ` Andrew Morton
2007-01-08 22:21 ` Shaya Potter
2007-01-08 23:34 ` Jan Engelhardt
2007-01-08 23:37 ` Josef Sipek
2007-01-09 0:03 ` Erez Zadok
2007-01-09 9:53 ` Christoph Hellwig
2007-01-09 10:43 ` Josef Sipek
2007-01-09 10:47 ` Christoph Hellwig
2007-01-09 10:48 ` Christoph Hellwig
2007-01-09 17:28 ` Erez Zadok
2007-01-08 23:25 ` Josef Sipek
2007-01-09 9:49 ` Christoph Hellwig
2007-01-09 10:36 ` Josef Sipek
2007-01-08 20:51 ` Erez Zadok
2007-01-08 21:53 ` Jan Engelhardt
2007-01-08 23:00 ` Michael Halcrow
2007-01-08 23:45 ` Josef Sipek
2007-01-09 0:19 ` Giuseppe Bilotta
2007-01-09 0:33 ` Josef Sipek
2007-01-09 1:26 ` Jan Engelhardt
2007-01-09 1:50 ` Shaya Potter
2007-01-09 12:26 ` Jan Kara
2007-01-09 16:39 ` Trond Myklebust
2007-01-09 17:04 ` Jan Kara
2007-01-09 17:07 ` Trond Myklebust
2007-01-09 17:34 ` Erez Zadok
2007-01-10 16:12 ` Jan Kara
2007-01-10 20:15 ` Erez Zadok
2007-01-10 20:24 ` Shaya Potter
2007-01-10 21:27 ` Jan Kara
2007-01-10 23:20 ` Josef Sipek
2007-01-10 23:29 ` Shaya Potter
2007-01-11 8:54 ` Jan Kara
2007-01-08 23:15 ` Josef Sipek
2007-01-09 12:15 ` Jan Kara
2007-01-09 16:30 ` Trond Myklebust
2007-01-09 16:41 ` Shaya Potter
2007-01-09 17:03 ` Trond Myklebust
2007-01-09 17:11 ` Shaya Potter
2007-01-09 17:16 ` Erez Zadok
2007-01-09 17:16 ` Jan Kara
2007-01-09 22:02 ` Jan Engelhardt
2007-01-11 14:29 ` Pavel Machek [this message]
2007-01-12 14:17 ` unionfs unusable on multiuser systems (was Re: [PATCH 01/24] Unionfs: Documentation) Shaya Potter
2007-01-08 4:12 ` [PATCH 02/24] lookup_one_len_nd - lookup_one_len with nameidata argument Josef 'Jeff' Sipek
2007-01-08 4:12 ` [PATCH 03/24] Unionfs: Branch management functionality Josef 'Jeff' Sipek
2007-01-08 4:12 ` [PATCH 04/24] Unionfs: Common file operations Josef 'Jeff' Sipek
2007-01-08 21:28 ` Andrew Morton
2007-01-08 4:12 ` [PATCH 05/24] Unionfs: Copyup Functionality Josef 'Jeff' Sipek
2007-01-08 21:29 ` Andrew Morton
2007-01-08 22:00 ` Shaya Potter
2007-01-08 4:12 ` [PATCH 06/24] Unionfs: Dentry operations Josef 'Jeff' Sipek
2007-01-08 21:29 ` Andrew Morton
2007-01-08 4:12 ` [PATCH 07/24] Unionfs: File operations Josef 'Jeff' Sipek
2007-01-08 4:13 ` [PATCH 08/24] Unionfs: Directory file operations Josef 'Jeff' Sipek
2007-01-08 4:13 ` [PATCH 09/24] Unionfs: Directory manipulation helper functions Josef 'Jeff' Sipek
2007-01-08 4:13 ` [PATCH 10/24] Unionfs: Inode operations Josef 'Jeff' Sipek
2007-01-08 4:13 ` [PATCH 11/24] Unionfs: Lookup helper functions Josef 'Jeff' Sipek
2007-01-08 4:13 ` [PATCH 12/24] Unionfs: Main module functions Josef 'Jeff' Sipek
2007-01-08 4:13 ` [PATCH 13/24] Unionfs: Readdir state Josef 'Jeff' Sipek
2007-01-08 4:13 ` [PATCH 14/24] Unionfs: Rename Josef 'Jeff' Sipek
2007-01-08 4:13 ` [PATCH 15/24] Unionfs: Privileged operations workqueue Josef 'Jeff' Sipek
2007-01-08 21:27 ` Andrew Morton
2007-01-08 4:13 ` [PATCH 16/24] Unionfs: Handling of stale inodes Josef 'Jeff' Sipek
2007-01-08 4:13 ` [PATCH 17/24] Unionfs: Miscellaneous helper functions Josef 'Jeff' Sipek
2007-01-08 4:13 ` [PATCH 18/24] Unionfs: Superblock operations Josef 'Jeff' Sipek
2007-01-08 21:29 ` Andrew Morton
2007-01-08 4:13 ` [PATCH 19/24] Unionfs: Helper macros/inlines Josef 'Jeff' Sipek
2007-01-08 21:28 ` Andrew Morton
2007-01-08 4:13 ` [PATCH 20/24] Unionfs: Internal include file Josef 'Jeff' Sipek
2007-01-08 4:13 ` [PATCH 21/24] Unionfs: Include file Josef 'Jeff' Sipek
2007-01-08 4:13 ` [PATCH 22/24] Unionfs: Unlink Josef 'Jeff' Sipek
2007-01-08 4:13 ` [PATCH 23/24] Unionfs: Kconfig and Makefile Josef 'Jeff' Sipek
2007-01-08 4:13 ` [PATCH 24/24] Unionfs: Extended Attributes support Josef 'Jeff' Sipek
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