Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1030544AbaDJTtt (ORCPT ); Thu, 10 Apr 2014 15:49:49 -0400 Received: from out1-smtp.messagingengine.com ([66.111.4.25]:47793 "EHLO out1-smtp.messagingengine.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1030242AbaDJTtr (ORCPT ); Thu, 10 Apr 2014 15:49:47 -0400 X-Sasl-enc: ruUV+3cS+tHzyHi960O49uBGJtSFqgpiUa+1WjbE6pNb 1397159385 Date: Thu, 10 Apr 2014 19:45:38 +0000 From: Colin Walters Subject: Re: [PATCH 0/6] File Sealing & memfd_create() To: Andy Lutomirski Cc: tytso@mit.edu, David Herrmann , linux-kernel@vger.kernel.org, Hugh Dickins , Alexander Viro , Matthew Wilcox , Karol Lewandowski , Kay Sievers , Daniel Mack , Lennart Poettering , Kristian@thunk.org, john.stultz@linaro.org, Greg Kroah-Hartman , Tejun Heo , Johannes Weiner , dri-devel@lists.freedesktop.org, linux-fsdevel@vger.kernel.org, linux-mm@kvack.org, Andrew Morton , Linus Torvalds , Ryan Lortie , mtk.manpages@gmail.com Message-Id: <1397159378.4434.1@mail.messagingengine.com> In-Reply-To: <5346EDE8.2060004@amacapital.net> References: <1395256011-2423-1-git-send-email-dh.herrmann@gmail.com> <20140320153250.GC20618@thunk.org> <1397141388.16343.10@mail.messagingengine.com> <5346EDE8.2060004@amacapital.net> X-Mailer: geary/0.6.0 MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8; format=flowed X-OriginalDate: Thu, 10 Apr 2014 19:45:38 -0004 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Apr 10, 2014 at 3:15 PM, Andy Lutomirski wrote: > > > COW links can do this already, I think. Of course, you'll have to > use a > filesystem that supports them. COW is nice if the filesystem supports them, but my userspace code needs to be filesystem agnostic. Because of that, the design for userspace simply doesn't allow arbitrary writes. Instead, I have to painfully audit every rpm %post/dpkg postinst type script to ensure they break hardlinks, and furthermore only allow executing scripts that are known to do so. But I think even in a btrfs world it'd still be useful to mark files as content-immutable. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/