Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752535AbaFCKMv (ORCPT ); Tue, 3 Jun 2014 06:12:51 -0400 Received: from mail-we0-f171.google.com ([74.125.82.171]:36812 "EHLO mail-we0-f171.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750786AbaFCKMt (ORCPT ); Tue, 3 Jun 2014 06:12:49 -0400 MIME-Version: 1.0 In-Reply-To: References: <1400799936-26499-1-git-send-email-keescook@chromium.org> From: Michael Kerrisk Date: Tue, 3 Jun 2014 12:12:27 +0200 X-Google-Sender-Auth: fnFVmG4noKoQoZ0qWTj2IjGh6k8 Message-ID: Subject: Re: [PATCH v5 0/6] seccomp: add PR_SECCOMP_EXT and SECCOMP_EXT_ACT_TSYNC To: Andy Lutomirski Cc: Kees Cook , Linux API , Andrew Morton , Oleg Nesterov , James Morris , Stephen Rothwell , "David S. Miller" , LKML , Will Drewry , Julien Tinnes , Alexei Starovoitov , Michael Kerrisk-manpages Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org [Kees, thank you for CCing linux-api] On Tue, Jun 3, 2014 at 1:08 AM, Andy Lutomirski wrote: > On Mon, Jun 2, 2014 at 4:05 PM, Kees Cook wrote: >> 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. prctl() is already a Franken-interface that provides a mass of different, mostly completely unrelated, functionality. So, I wonder if it would be better not to make the situation worse. Furthermore, the very fact that the existing prctl seccomp API is being extended and multiplexed suggests that other extensions might be desirable further down the line, which also hints that a separate syscall would be a good idea. (Or do we have to wait until the prctl seccomp API is extended one more time, before we realize that a new system call would have been a good idea...) > TBH, I care more about the atomicity thing than about the actual form > of the API. User-space does not necessarily thank you for that perspective, Andy ;-). The atomicity thing is presumably fixable, regardless of the API. On the other hand, APIs are things that kernel developers design once and forget about, and user-space has to live with forever. Cheers, Michael -- 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/