From mboxrd@z Thu Jan  1 00:00:00 1970
Return-Path: <linux-kernel-owner@vger.kernel.org>
Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand
	id S1756665Ab3HYUGO (ORCPT <rfc822;w@1wt.eu>);
	Sun, 25 Aug 2013 16:06:14 -0400
Received: from zeniv.linux.org.uk ([195.92.253.2]:43731 "EHLO
	ZenIV.linux.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org
	with ESMTP id S1753799Ab3HYUGM (ORCPT
	<rfc822;linux-kernel@vger.kernel.org>);
	Sun, 25 Aug 2013 16:06:12 -0400
Date: Sun, 25 Aug 2013 21:06:06 +0100
From: Al Viro <viro@ZenIV.linux.org.uk>
To: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Andy Lutomirski <luto@amacapital.net>, Willy Tarreau <w@1wt.eu>,
        "security@kernel.org" <security@kernel.org>,
        Ingo Molnar <mingo@kernel.org>,
        Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
        Oleg Nesterov <oleg@redhat.com>,
        Linux FS Devel <linux-fsdevel@vger.kernel.org>,
        Brad Spengler <spender@grsecurity.net>
Subject: Re: [PATCH v2] vfs: Tighten up linkat(..., AT_EMPTY_PATH)
Message-ID: <20130825200605.GC27005@ZenIV.linux.org.uk>
References: <CA+55aFw3AM2Xe2aNUKk0x8ZrZHbY4QnaRZbZdAqf1trT+dGDmQ@mail.gmail.com>
 <CALCETrU2xBykonV2N8bSysdycfZkCq_P5bUnrN5SjZo2_5dNrg@mail.gmail.com>
 <20130822201530.GL31117@1wt.eu>
 <CALCETrXX--FWeoDMOTYNDOWkTKcWk=LcGs2oY7CQ9GU63CMLRg@mail.gmail.com>
 <CA+55aFzR71kJOOVzHKKaXW2Ph7wb6ivtVHPeR49PPcqpiCfPsA@mail.gmail.com>
 <CALCETrXXxRksU-YTY8WFJzeET9cWsPKo_=6e9RD=F+TS7xVMyQ@mail.gmail.com>
 <CA+55aFxqdV6CQ8UWkB1Z7HUB9GmRH4Jpw_UmmFqDqG01_DmsWw@mail.gmail.com>
 <20130823010726.GP27005@ZenIV.linux.org.uk>
 <20130825033741.GX27005@ZenIV.linux.org.uk>
 <CA+55aFxaKGcpdxKXK_axqyFz_oCvFm1Q=_fJLq8di97x_-cCig@mail.gmail.com>
MIME-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Content-Disposition: inline
In-Reply-To: <CA+55aFxaKGcpdxKXK_axqyFz_oCvFm1Q=_fJLq8di97x_-cCig@mail.gmail.com>
User-Agent: Mutt/1.5.21 (2010-09-15)
Sender: linux-kernel-owner@vger.kernel.org
List-ID: <linux-kernel.vger.kernel.org>
X-Mailing-List: linux-kernel@vger.kernel.org

On Sun, Aug 25, 2013 at 12:57:25PM -0700, Linus Torvalds wrote:

> Yes. I think we should do this, but I think we should also look at
> what _other_ LOOKUP_xyz we should do for the /proc case.
> 
> For the read-only fd case, we should have a LOOKUP_WRITE flag, and
> return -EPERM if an operation is a write, and we terminate in that
> LAST_BIND case.
> 
> That would catch the truncate() case, but also the "open a read-only
> fd for write or O_TRUNC" case.
> 
> Anything else? What other path operations matter that follow links
> than truncate(), link() and open()?

Timestamp updates, chmod/chown, xattr mess...