From: Theodore Ts'o <tytso@mit.edu>
To: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Dave Chinner <david@fromorbit.com>,
Andy Lutomirski <luto@amacapital.net>,
One Thousand Gnomes <gnomes@lxorguk.ukuu.org.uk>,
Ric Wheeler <rwheeler@redhat.com>,
Gregory Farnum <greg@gregs42.com>,
"Martin K. Petersen" <martin.petersen@oracle.com>,
Christoph Hellwig <hch@infradead.org>,
"Darrick J. Wong" <darrick.wong@oracle.com>,
Jens Axboe <axboe@kernel.dk>,
Andrew Morton <akpm@linux-foundation.org>,
Linux API <linux-api@vger.kernel.org>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
shane.seymour@hpe.com, Bruce Fields <bfields@fieldses.org>,
linux-fsdevel <linux-fsdevel@vger.kernel.org>,
Jeff Layton <jlayton@poochiereds.net>,
Eric Sandeen <esandeen@redhat.com>
Subject: Re: [PATCH 2/2] block: create ioctl to discard-or-zeroout a range of blocks
Date: Sat, 12 Mar 2016 02:19:45 -0500 [thread overview]
Message-ID: <20160312071945.GA3419@thunk.org> (raw)
In-Reply-To: <CA+55aFyLa0iFFkiVZq-nLH2yWoGzGnv8HB=4R1Xq2PRmjusJ=w@mail.gmail.com>
On Fri, Mar 11, 2016 at 04:44:16PM -0800, Linus Torvalds wrote:
> On Fri, Mar 11, 2016 at 4:35 PM, Theodore Ts'o <tytso@mit.edu> wrote:
> >
> > At the end of the day it's about whether you trust the userspace
> > program or not.
>
> There's a big difference between "give the user rope", and "tie the
> rope in a noose and put a banana peel so that the user might stumble
> into the rope and hang himself", though.
So let's see. The user application has to explicitly request
NO_HIDE_STALE via an fallocate flag --- so it requires changing the
source code and recompiling the application. And then, the system
administrator has to pass in a mount option specifying a group that
the application has to run under. And then the application has to run
setgid with that group's privileges.
I hardly think that can be considered handing the user a pre-tied
noose.
Sure, the application can do something stupid --- but I'd arguing
giving root to some junior sysadmin is far more likely to cause
problems.
Cheers,
- Ted
next prev parent reply other threads:[~2016-03-12 7:20 UTC|newest]
Thread overview: 82+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-03-02 4:09 [PATCH v5.1 0/2] create BLKZEROOUT ioctl that invalidates page cache Darrick J. Wong
2016-03-02 4:09 ` [PATCH 1/2] block: invalidate the page cache when issuing BLKZEROOUT Darrick J. Wong
2016-03-02 9:19 ` Christoph Hellwig
2016-03-02 4:09 ` [PATCH 2/2] block: create ioctl to discard-or-zeroout a range of blocks Darrick J. Wong
2016-03-02 9:20 ` Christoph Hellwig
2016-03-02 18:52 ` Linus Torvalds
2016-03-02 22:56 ` Darrick J. Wong
2016-03-02 23:49 ` Linus Torvalds
2016-03-03 17:02 ` Theodore Ts'o
2016-03-03 17:55 ` Linus Torvalds
2016-03-03 18:00 ` Christoph Hellwig
2016-03-03 18:14 ` Martin K. Petersen
2016-03-03 18:21 ` Theodore Ts'o
2016-03-03 18:01 ` Martin K. Petersen
2016-03-03 18:09 ` Christoph Hellwig
2016-03-03 18:12 ` Darrick J. Wong
2016-03-03 18:54 ` Martin K. Petersen
2016-03-03 22:39 ` Theodore Ts'o
2016-03-03 23:10 ` Dave Chinner
2016-03-04 0:20 ` Theodore Ts'o
2016-03-09 22:20 ` Gregory Farnum
2016-03-09 23:08 ` Theodore Ts'o
2016-03-10 14:58 ` Ric Wheeler
2016-03-10 18:33 ` Linus Torvalds
2016-03-10 21:47 ` Theodore Ts'o
2016-03-11 4:42 ` Ric Wheeler
2016-03-11 13:59 ` One Thousand Gnomes
2016-03-11 15:27 ` Theodore Ts'o
2016-03-11 17:23 ` Linus Torvalds
2016-03-11 17:30 ` Andy Lutomirski
2016-03-11 18:25 ` Linus Torvalds
2016-03-11 22:30 ` Dave Chinner
2016-03-12 0:33 ` Linus Torvalds
2016-03-12 0:35 ` Theodore Ts'o
2016-03-12 0:44 ` Linus Torvalds
2016-03-12 7:19 ` Theodore Ts'o [this message]
2016-03-12 10:11 ` Thomas Schoebel-Theuer
2016-03-13 23:30 ` Dave Chinner
2016-03-14 10:34 ` Ric Wheeler
2016-03-14 14:46 ` Theodore Ts'o
2016-03-15 20:14 ` Dave Chinner
2016-03-15 20:43 ` Linus Torvalds
2016-03-15 21:29 ` Theodore Ts'o
2016-03-15 22:33 ` Dave Chinner
2016-03-15 22:52 ` Theodore Ts'o
2016-03-16 1:51 ` Darrick J. Wong
2016-03-16 21:45 ` Andreas Dilger
2016-03-17 0:15 ` Theodore Ts'o
2016-03-17 0:33 ` Eric Sandeen
2016-03-17 0:59 ` Theodore Ts'o
2016-03-17 5:18 ` Gregory Farnum
2016-03-17 12:36 ` Theodore Ts'o
2016-03-17 17:47 ` Linus Torvalds
2016-03-17 17:50 ` Ric Wheeler
2016-03-17 17:59 ` Linus Torvalds
2016-03-17 18:35 ` Chris Mason
2016-03-17 20:49 ` Andreas Dilger
2016-03-17 21:00 ` Chris Mason
2016-03-18 3:20 ` Theodore Ts'o
2016-03-18 15:15 ` Jeff Moyer
2016-03-18 20:05 ` Martin K. Petersen
2016-03-18 6:52 ` Gregory Farnum
2016-03-18 7:19 ` Linus Torvalds
2016-03-17 1:01 ` Dave Chinner
2016-03-17 2:38 ` Darrick J. Wong
2016-03-18 22:55 ` NeilBrown
2016-03-15 23:06 ` Linus Torvalds
2016-03-15 23:14 ` Linus Torvalds
2016-03-16 0:08 ` Dave Chinner
2016-03-15 23:52 ` Dave Chinner
2016-03-16 0:06 ` Linus Torvalds
2016-03-16 0:30 ` Eric Sandeen
2016-03-16 0:51 ` Chris Mason
2016-03-16 22:23 ` Chris Mason
2016-03-17 13:49 ` Ric Wheeler
2016-03-15 22:38 ` Eric Sandeen
2016-03-03 22:56 ` Dave Chinner
2016-03-04 2:30 ` Thomas Schoebel-Theuer
2016-03-03 18:14 ` Linus Torvalds
2016-03-02 9:15 ` [PATCH v5.1 0/2] create BLKZEROOUT ioctl that invalidates page cache Arnd Bergmann
2016-03-02 9:44 ` Christoph Hellwig
2016-03-02 10:55 ` Arnd Bergmann
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