Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932200AbaFBVSL (ORCPT ); Mon, 2 Jun 2014 17:18:11 -0400 Received: from mail-vc0-f173.google.com ([209.85.220.173]:44709 "EHLO mail-vc0-f173.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752465AbaFBVSK (ORCPT ); Mon, 2 Jun 2014 17:18:10 -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 14:17:49 -0700 Message-ID: Subject: Re: [PATCH v5 0/6] seccomp: add PR_SECCOMP_EXT and SECCOMP_EXT_ACT_TSYNC To: Kees Cook Cc: 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 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. :) > >> wouldn't be better off it it were completely atomic in the sense that >> it would either work or fail without doing anything. > > Getting perfect atomic operation looks extremely hard given task > locking. If this could get fixed in the future, it would have no > impact on the interface. At present, the corner case of the racing > thread is small enough that just catching the race failure is > sufficient. If task locking is improved in the future, it could just > simply never lose a race. Userspace still needs to handle errors no > matter what is the non-race failure condition (mode 1 or forked > filter) still exists. > I think it's doable -- I just replied to the other thread. > -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/