From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755265Ab2AQQbP (ORCPT ); Tue, 17 Jan 2012 11:31:15 -0500 Received: from mx1.redhat.com ([209.132.183.28]:53420 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754841Ab2AQQbM (ORCPT ); Tue, 17 Jan 2012 11:31:12 -0500 Date: Tue, 17 Jan 2012 17:23:09 +0100 From: Oleg Nesterov To: Andy Lutomirski Cc: Casey Schaufler , Linus Torvalds , Jamie Lokier , Will Drewry , linux-kernel@vger.kernel.org, keescook@chromium.org, john.johansen@canonical.com, serge.hallyn@canonical.com, coreyb@linux.vnet.ibm.com, pmoore@redhat.com, eparis@redhat.com, djm@mindrot.org, segoon@openwall.com, rostedt@goodmis.org, jmorris@namei.org, scarybeasts@gmail.com, avi@redhat.com, penberg@cs.helsinki.fi, viro@zeniv.linux.org.uk, mingo@elte.hu, akpm@linux-foundation.org, khilman@ti.com, borislav.petkov@amd.com, amwang@redhat.com, ak@linux.intel.com, eric.dumazet@gmail.com, gregkh@suse.de, dhowells@redhat.com, daniel.lezcano@free.fr, linux-fsdevel@vger.kernel.org, linux-security-module@vger.kernel.org, olofj@chromium.org, mhalcrow@google.com, dlaor@redhat.com, corbet@lwn.net, alan@lxorguk.ukuu.org.uk Subject: Re: [PATCH 4/4] Allow unprivileged chroot when safe Message-ID: <20120117162309.GA16336@redhat.com> References: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.18 (2008-05-17) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 01/15, Andy Lutomirski wrote: > > Chroot can easily be used to subvert setuid programs. If no_new_privs, > then setuid programs don't gain any privilege, so allow chroot. > > ... > > + if (!(current->no_new_privs && !is_chrooted) && > + !capable(CAP_SYS_CHROOT)) I must have missed something. How no_new_privs can help if fs->users != 1 ? Oleg.