From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751346AbeBUUG3 (ORCPT ); Wed, 21 Feb 2018 15:06:29 -0500 Received: from mail.linuxfoundation.org ([140.211.169.12]:60030 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750716AbeBUUG2 (ORCPT ); Wed, 21 Feb 2018 15:06:28 -0500 Date: Wed, 21 Feb 2018 12:06:27 -0800 From: Andrew Morton To: Alexey Dobriyan Cc: linux-kernel@vger.kernel.org Subject: Re: [PATCH 1/5] proc: make /proc/*/cmdline go through LSM Message-Id: <20180221120627.9e134187df86df7c08ad78ca@linux-foundation.org> In-Reply-To: <20180221192339.GA28548@avx2> References: <20180221192339.GA28548@avx2> X-Mailer: Sylpheed 3.6.0 (GTK+ 2.24.31; x86_64-pc-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, 21 Feb 2018 22:23:39 +0300 Alexey Dobriyan wrote: > /proc/*/cmdline is not different from /proc/*/environ as it accesses > target task's memory (and can access the very same region of memory) > but it doesn't go through ptrace_may_access() and thus doesn't go through LSM. > I'd really like to see more thoughtful changelogging, please. Why are we doing this? What is the advantage? Doesn't this mean that code which could previously read /proc/pid/cmdline may no longer be able to do so? Can't this break userspace? Discuss. Lots!