From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752525Ab2ALQV3 (ORCPT ); Thu, 12 Jan 2012 11:21:29 -0500 Received: from mx1.redhat.com ([209.132.183.28]:18841 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751664Ab2ALQV1 (ORCPT ); Thu, 12 Jan 2012 11:21:27 -0500 Date: Thu, 12 Jan 2012 17:14:18 +0100 From: Oleg Nesterov To: Steven Rostedt Cc: 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, torvalds@linux-foundation.org, segoon@openwall.com, jmorris@namei.org, scarybeasts@gmail.com, avi@redhat.com, penberg@cs.helsinki.fi, viro@zeniv.linux.org.uk, luto@mit.edu, 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 Subject: Re: [RFC,PATCH 1/2] seccomp_filters: system call filtering using BPF Message-ID: <20120112161418.GA22360@redhat.com> References: <1326302710-9427-1-git-send-email-wad@chromium.org> <1326302710-9427-2-git-send-email-wad@chromium.org> <1326383015.7642.77.camel@gandalf.stny.rr.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1326383015.7642.77.camel@gandalf.stny.rr.com> 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 01/12, Steven Rostedt wrote: > > On Wed, 2012-01-11 at 11:25 -0600, Will Drewry wrote: > > > Filter programs may _only_ cross the execve(2) barrier if last filter > > program was attached by a task with CAP_SYS_ADMIN capabilities in its > > user namespace. Once a task-local filter program is attached from a > > process without privileges, execve will fail. This ensures that only > > privileged parent task can affect its privileged children (e.g., setuid > > binary). > > This means that a non privileged user can not run another program with > limited features? How would a process exec another program and filter > it? I would assume that the filter would need to be attached first and > then the execv() would be performed. But after the filter is attached, > the execv is prevented? > > Maybe I don't understand this correctly. May be this needs something like LSM_UNSAFE_SECCOMP, or perhaps cap_bprm_set_creds() should take seccomp.mode == 2 into account, I dunno. OTOH, currently seccomp.mode == 1 doesn't allow to exec at all. Oleg.