From: Al Viro <viro@ZenIV.linux.org.uk>
To: Pavel Machek <pavel@ucw.cz>
Cc: Jeff Layton <jlayton@redhat.com>,
Jamie Lokier <jamie@shareable.org>,
"Eric W. Biederman" <ebiederm@xmission.com>,
linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org,
miklos@szeredi.hu
Subject: Re: [PATCH 0/3] vfs: plug some holes involving LAST_BIND symlinks and file bind mounts (try #5)
Date: Sun, 20 Dec 2009 21:04:04 +0000 [thread overview]
Message-ID: <20091220210404.GN18217@ZenIV.linux.org.uk> (raw)
In-Reply-To: <20091220195903.GG23917@elf.ucw.cz>
On Sun, Dec 20, 2009 at 08:59:03PM +0100, Pavel Machek wrote:
> > WTF not? It's convenient and doesn't lose any real security. If your
> > code relies on inaccessibility of <path> since some component of that
> > path is inaccessible, you are *already* fscked. Consider e.g. fchdir()
> > and its implications - if you have an opened descriptor for parent,
> > having no exec permissions on grandparent won't stop you at all. Already.
> > On all Unices, regardless of openat(), etc.
>
> Consider FD passing over unix socket. Passing R/O file descriptor to
> the other task, then having the task write to the file is certainly bad.
You've omitted the "R/O file descriptor of a file that is writable for
that other task" part...
next prev parent reply other threads:[~2009-12-20 21:04 UTC|newest]
Thread overview: 28+ messages / expand[flat|nested] mbox.gz Atom feed top
2009-11-23 17:41 [PATCH 0/3] vfs: plug some holes involving LAST_BIND symlinks and file bind mounts (try #5) Jeff Layton
2009-11-23 17:41 ` [PATCH 1/3] vfs: force reval of target when following LAST_BIND symlinks Jeff Layton
2009-11-23 17:41 ` [PATCH 2/3] vfs: force reval on dentry of bind mounted files on FS_REVAL_DOT filesystems Jeff Layton
2009-11-23 17:41 ` [PATCH 3/3] vfs: check path permissions on target of LAST_BIND symlinks Jeff Layton
2009-11-23 22:05 ` [PATCH 0/3] vfs: plug some holes involving LAST_BIND symlinks and file bind mounts (try #5) Eric W. Biederman
2009-11-23 22:36 ` Jeff Layton
2009-11-23 22:49 ` Jamie Lokier
2009-11-23 23:15 ` Jeff Layton
2009-11-23 23:35 ` Eric W. Biederman
2009-11-24 0:34 ` Jeff Layton
2009-11-24 1:20 ` Jamie Lokier
2009-11-24 11:26 ` Jeff Layton
2009-11-24 11:53 ` Miklos Szeredi
2009-11-24 12:09 ` Pavel Machek
2009-11-24 12:59 ` Miklos Szeredi
2009-11-30 12:28 ` Pavel Machek
2009-11-30 19:21 ` Eric W. Biederman
2009-11-24 13:13 ` Duane Griffin
2009-11-30 19:00 ` Jamie Lokier
2009-12-01 8:56 ` Duane Griffin
2009-12-16 12:31 ` Al Viro
2009-12-20 19:59 ` Pavel Machek
2009-12-20 21:04 ` Al Viro [this message]
2009-12-20 21:06 ` Pavel Machek
2009-12-20 21:23 ` Al Viro
2010-01-01 15:40 ` Pavel Machek
2010-01-10 4:42 ` Al Viro
2009-12-01 13:15 ` Jeff Layton
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