From: Jamie Lokier <jamie@shareable.org>
To: Miklos Szeredi <miklos@szeredi.hu>
Cc: Valdis.Kletnieks@vt.edu, linux@treblig.org, agruen@suse.de,
linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH] vfs: new O_NODE open flag
Date: Mon, 28 Sep 2009 15:10:25 +0100 [thread overview]
Message-ID: <20090928141025.GF19778@shareable.org> (raw)
In-Reply-To: <E1MsGtJ-0001xy-5T@pomaz-ex.szeredi.hu>
Miklos Szeredi wrote:
> > Hmm. I have just tried, and you _can _use open("/proc/self/fd/%d",
> > O_RDWR) to re-open with more permissions when you can't access the
> > path which /proc/self/fd/%d pretends to link to. It looks a bit
> > dubious, as you might have been passed an O_RDONLY descriptor with the
> > intention that you can't write to it... Oh well!
>
> True, /proc gives you access to the underlying "path" of an open file
> descriptor. If you don't want that, don't mount /proc in your limited
> namespace.
I wasn't using a limited namespace.
Just a directory without permission to be searched, and as a regular
user - which is historically supposed to prevent you from opening
files in it.
-- Jamie
next prev parent reply other threads:[~2009-09-28 14:10 UTC|newest]
Thread overview: 24+ messages / expand[flat|nested] mbox.gz Atom feed top
2009-09-24 14:51 [PATCH] vfs: new O_NODE open flag Miklos Szeredi
2009-09-25 0:23 ` Andreas Gruenbacher
2009-09-25 5:52 ` Miklos Szeredi
2009-09-25 12:37 ` Dr. David Alan Gilbert
2009-09-25 12:18 ` Miklos Szeredi
2009-09-25 17:08 ` Jamie Lokier
2009-09-25 16:53 ` Andreas Dilger
2009-09-25 17:20 ` Valdis.Kletnieks
2009-09-25 18:35 ` Dr. David Alan Gilbert
2009-09-25 21:18 ` Valdis.Kletnieks
2009-09-28 10:25 ` Miklos Szeredi
2009-09-28 13:28 ` Jamie Lokier
2009-09-28 14:07 ` Miklos Szeredi
2009-09-28 14:10 ` Jamie Lokier [this message]
2009-09-30 8:18 ` Florian Weimer
2009-09-30 8:18 ` Florian Weimer
2009-09-28 15:21 ` Andreas Dilger
2009-09-28 16:04 ` Miklos Szeredi
2009-10-04 19:03 ` Pavel Machek
2009-10-04 22:58 ` Jamie Lokier
2009-10-23 17:10 ` /proc filesystem allows bypassing directory permissions on Linux (was Re: [PATCH] vfs: new O_NODE open flag) Pavel Machek
2009-10-14 13:14 ` [PATCH] vfs: new O_NODE open flag Andreas Gruenbacher
2009-09-25 19:02 ` Andreas Dilger
2009-09-28 15:53 ` Jamie Lokier
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