From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756218Ab2APTaS (ORCPT ); Mon, 16 Jan 2012 14:30:18 -0500 Received: from mx1.redhat.com ([209.132.183.28]:50667 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755630Ab2APTaQ (ORCPT ); Mon, 16 Jan 2012 14:30:16 -0500 Date: Mon, 16 Jan 2012 19:37:30 +0100 From: Oleg Nesterov To: Will Drewry Cc: 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, rostedt@goodmis.org, 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, Roland McGrath , Andi Kleen , indan@nul.nu Subject: Re: [RFC,PATCH 1/2] seccomp_filters: system call filtering using BPF Message-ID: <20120116183730.GB21112@redhat.com> References: <1326302710-9427-1-git-send-email-wad@chromium.org> <1326302710-9427-2-git-send-email-wad@chromium.org> <20120112162231.GA23960@redhat.com> <20120112172315.GA26295@redhat.com> <20120113173153.GA24273@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline Content-Transfer-Encoding: 8bit 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 01/13, Will Drewry wrote: > > On Fri, Jan 13, 2012 at 1:01 PM, Will Drewry wrote: > > On Fri, Jan 13, 2012 at 11:31 AM, Oleg Nesterov wrote: > >> > >> Me too. I see no point in using user_regs_struct. > > > > I'll rev the change to use pt_regs and drop all the helper code.  If > > no one says otherwise, that certainly seems ideal from a performance > > perspective, and I see pt_regs exported to userland along with ptrace > > abi register offset macros. > > On second thought, pt_regs is scary :) > > From looking at > http://lxr.linux.no/linux+v3.2.1/arch/x86/include/asm/syscall.h#L97 > and ia32syscall enty code, it appears that for x86, at least, the > pt_regs for compat processes will be 8 bytes wide per register on the > stack. This means if a self-filtering 32-bit program runs on a 64-bit host in > IA32_EMU, its filters will always index into pt_regs incorrectly. Yes, thanks, I forgot about compat tasks again. But this is easy, just we need regs_64_to_32(). Doesn't matter. I think Indan has a better suggestion. Oleg.