From: Al Viro <viro@ftp.linux.org.uk>
To: Mark Lord <lkml@rtr.ca>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>,
Andrew Morton <akpm@linux-foundation.org>,
Linux Kernel <linux-kernel@vger.kernel.org>
Subject: Re: RFC: permit link(2) to work across --bind mounts ?
Date: Tue, 18 Dec 2007 23:14:04 +0000 [thread overview]
Message-ID: <20071218231404.GG8181@ftp.linux.org.uk> (raw)
In-Reply-To: <20071218230016.GF8181@ftp.linux.org.uk>
On Tue, Dec 18, 2007 at 11:00:16PM +0000, Al Viro wrote:
> On Tue, Dec 18, 2007 at 05:46:21PM -0500, Mark Lord wrote:
> > Why does link(2) not support hard-linking across bind mount points
> > of the same underlying filesystem ?
>
> Because it gives you a security boundary around a subtree.
PS: that had been discussed quite a few times, but to avoid searches:
consider e.g. mount --bind /tmp /tmp; now you've got a situation when
users can't create links to elsewhere no root fs, even though they
have /tmp writable to them. Similar technics works for other isolation
needs - basically, you can confine rename/link to given subtree. IOW,
it's a deliberate feature. Note that you can bind a bunch of trees
into chroot and get predictable restrictions regardless of how the
stuff might get rearranged a year later in the main tree, etc.
next prev parent reply other threads:[~2007-12-18 23:14 UTC|newest]
Thread overview: 26+ messages / expand[flat|nested] mbox.gz Atom feed top
2007-12-18 22:46 RFC: permit link(2) to work across --bind mounts ? Mark Lord
2007-12-18 22:57 ` Mark Lord
2007-12-18 23:00 ` Al Viro
2007-12-18 23:14 ` Al Viro [this message]
2007-12-19 3:54 ` Mark Lord
2007-12-19 3:59 ` David Newall
2007-12-19 16:47 ` Mark Lord
2007-12-19 18:38 ` David Newall
2007-12-29 2:53 ` dean gaudet
2007-12-29 3:31 ` Jan Engelhardt
2007-12-29 6:02 ` dean gaudet
2007-12-29 6:48 ` Jan Engelhardt
2007-12-29 8:29 ` David Newall
2007-12-29 16:18 ` dean gaudet
2007-12-29 20:35 ` David Newall
2007-12-29 20:40 ` dean gaudet
2007-12-30 3:43 ` Valdis.Kletnieks
2007-12-30 3:55 ` dean gaudet
2007-12-27 3:43 ` Rogelio M. Serrano Jr.
[not found] <9BTqk-2ck-31@gated-at.bofh.it>
[not found] ` <9BTJN-2Sv-21@gated-at.bofh.it>
[not found] ` <9BTTr-35L-13@gated-at.bofh.it>
2007-12-19 13:43 ` Bodo Eggert
2007-12-19 14:23 ` Al Viro
2007-12-19 15:42 ` Johannes Weiner
2007-12-19 16:44 ` Mark Lord
2007-12-20 20:55 ` Bodo Eggert
-- strict thread matches above, loose matches on Subject: below --
2007-12-20 1:33 linux
2007-12-20 2:06 ` Mark Lord
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