From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752439AbcGLIzI (ORCPT ); Tue, 12 Jul 2016 04:55:08 -0400 Received: from mail-lf0-f65.google.com ([209.85.215.65]:34346 "EHLO mail-lf0-f65.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751669AbcGLIzC (ORCPT ); Tue, 12 Jul 2016 04:55:02 -0400 Subject: Re: [PATCH] capabilities: audit capability use To: "Eric W. Biederman" References: <1468235672-3745-1-git-send-email-toiwoton@gmail.com> <87vb0bbzyo.fsf@x220.int.ebiederm.org> Cc: linux-kernel@vger.kernel.org, pmladek@suse.com, luto@kernel.org, serge@hallyn.com, keescook@chromium.org, Paul Moore , Eric Paris , Tejun Heo , Li Zefan , Johannes Weiner , "moderated list:AUDIT SUBSYSTEM" , "open list:CONTROL GROUP (CGROUP)" , "open list:CAPABILITIES" From: Topi Miettinen Openpgp: id=A0F2EB0D8452DA908BEC8E911CF9ADDBD610E936 Message-ID: Date: Tue, 12 Jul 2016 08:54:41 +0000 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:45.0) Gecko/20100101 Icedove/45.1.0 MIME-Version: 1.0 In-Reply-To: <87vb0bbzyo.fsf@x220.int.ebiederm.org> Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 07/11/16 21:57, Eric W. Biederman wrote: > Topi Miettinen writes: > >> There are many basic ways to control processes, including capabilities, >> cgroups and resource limits. However, there are far fewer ways to find >> out useful values for the limits, except blind trial and error. >> >> Currently, there is no way to know which capabilities are actually used. >> Even the source code is only implicit, in-depth knowledge of each >> capability must be used when analyzing a program to judge which >> capabilities the program will exercise. >> >> Generate an audit message at system call exit, when capabilities are used. >> This can then be used to configure capability sets for services by a >> software developer, maintainer or system administrator. >> >> Test case demonstrating basic capability monitoring with the new >> message types 1330 and 1331 and how the cgroups are displayed (boot to >> rdshell): > > You totally miss the interactions with the user namespace so this won't > give you the information you are aiming for. Please correct me if this is not right: There are two cases: a) real capability use as seen outside the namespace b) use of capabilities granted by the namespace Both cases could be active independently. For auditing purposes, we're mostly interested in a) and log noise from b) could be even seen a distraction. For configuration purposes, both cases can be interesting, a) for the configuration of services and b) in case where the containerized configuration is planned to be deployed outside. I'd still only log a). The same logic should apply with cgroup namespaces. -Topi > > Eric >