Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752838AbaFBXIx (ORCPT ); Mon, 2 Jun 2014 19:08:53 -0400 Received: from mail-vc0-f176.google.com ([209.85.220.176]:63426 "EHLO mail-vc0-f176.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751800AbaFBXIv (ORCPT ); Mon, 2 Jun 2014 19:08:51 -0400 MIME-Version: 1.0 In-Reply-To: References: <1400799936-26499-1-git-send-email-keescook@chromium.org> From: Andy Lutomirski Date: Mon, 2 Jun 2014 16:08:30 -0700 Message-ID: Subject: Re: [PATCH v5 0/6] seccomp: add PR_SECCOMP_EXT and SECCOMP_EXT_ACT_TSYNC To: Kees Cook Cc: Linux API , Andrew Morton , Oleg Nesterov , James Morris , Stephen Rothwell , "David S. Miller" , LKML , Will Drewry , Julien Tinnes , Alexei Starovoitov Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Jun 2, 2014 at 4:05 PM, Kees Cook wrote: > On Mon, Jun 2, 2014 at 2:17 PM, Andy Lutomirski wrote: >> On Mon, Jun 2, 2014 at 1:06 PM, Kees Cook wrote: >>> On Mon, Jun 2, 2014 at 12:59 PM, Andy Lutomirski wrote: >>>> On Mon, Jun 2, 2014 at 12:47 PM, Kees Cook wrote: >>>>> Hi Andrew, >>>>> >>>>> Would you be willing to carry this series? Andy Lutomirski appears >>>>> happy with it now. (Thanks again for all the feedback Andy!) If so, it >>>>> has a relatively small merge conflict with the bpf changes living in >>>>> net-next. Would you prefer I rebase against net-next, let sfr handle >>>>> it, get carried in net-next, or some other option? >>>> >>>> Well, I'm still not entirely convinced that we want to have this much >>>> multiplexing in a prctl, and I'm still a bit unconvinced that the code >>> >>> I don't want to get caught without interface argument flexibility >>> again, so that's why the prctl interface is being set up that way. >> >> I was thinking that a syscall might be a lot prettier. It may pay to >> cc linux-api, too. >> >> I'll offer you a deal: if you try to come up with a nice, clean >> syscall, I'll try to write a fast(er) path for x86_64 to reduce >> overhead. I bet I can save 90-100ns per syscall. :) > > Now added to the Cc. > > Which path do you mean to improve? Neither the prctl nor a syscall for > this would need to be fast at all. Non-seccomp-related syscalls when seccomp is enabled. > > I don't want to go in circles on this. I've been there before on my > VFS link hardening series, and my module restriction series. I would > like consensus from more than just one person. :) I can't offer you anyone else's review, unfortunately :-/ > > I'd like to hear from other folks on this (akpm?). My instinct is to > continue using prctl since that is already where mediation for seccomp > happens. I don't see why prctl vs a new syscall makes a difference > here, frankly. Aesthetics? There's a tendency for people to get annoyed at big multiplexed APIs, and your patches will be doubly multiplexed. TBH, I care more about the atomicity thing than about the actual form of the API. --Andy > > -Kees > > -- > Kees Cook > Chrome OS Security -- Andy Lutomirski AMA Capital Management, LLC -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/