Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751476AbdISVny (ORCPT ); Tue, 19 Sep 2017 17:43:54 -0400 Received: from mail-it0-f45.google.com ([209.85.214.45]:54983 "EHLO mail-it0-f45.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751074AbdISVnw (ORCPT ); Tue, 19 Sep 2017 17:43:52 -0400 X-Google-Smtp-Source: AOwi7QDYka1Dh3ipBsz9t0EHyq0juX5o2x/d1SbXK6vt6lbKl4Cd1JdPeadEE9RzyghOAsAVny3CgFlP4LmWse8b35s= MIME-Version: 1.0 In-Reply-To: <20170919210916.6r5janszdtx7eoes@smitten> References: <20170919174743.19814-1-tycho@docker.com> <20170919210916.6r5janszdtx7eoes@smitten> From: Kees Cook Date: Tue, 19 Sep 2017 14:43:51 -0700 X-Google-Sender-Auth: WJyf3tJj4yn2KlFHKkcvqlscb7o Message-ID: Subject: Re: [PATCH] ptrace, seccomp: add support for retrieving seccomp flags To: Tycho Andersen Cc: LKML , criu@openvz.org, Andy Lutomirski , Oleg Nesterov Content-Type: text/plain; charset="UTF-8" Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1473 Lines: 37 On Tue, Sep 19, 2017 at 2:09 PM, Tycho Andersen wrote: > Hi Kees, > > On Tue, Sep 19, 2017 at 01:08:28PM -0700, Kees Cook wrote: >> On Tue, Sep 19, 2017 at 10:47 AM, Tycho Andersen wrote: >> > With the new SECCOMP_FILTER_FLAG_LOG, we need to be able to extract these >> > flags for checkpoint restore, since they describe the state of a filter. >> > >> > So, let's add PTRACE_SECCOMP_GET_FLAGS, similar to ..._GET_FILTER, which >> > returns the flags of the nth filter. >> >> Can you split this up into factoring out the nth helper, and then >> adding the new get? >> >> For naming, perhaps "GET_FILTER_FLAGS" instead of "GET_FLAGS" since >> there may be seccomp flags in the future, etc. > > Sure, I'll do both of these. > >> Is there any sane way to add the flags to the existing GET_FILTER? > > I looked at this, and I don't think so. Unfortunately, we didn't use > any structure for the output, it's just the raw bytes of the filter > with the length used as the return value. I suppose we could append > the flags after the bytes of the filter, but that seems... very ugly > :). Let me know if you want to go that route. I think if we can make the new GET_FILTER_stuff interface more extensible, we should cover any future needs for per-filter content. BUt yeah, I agree, when I looked at this when I first mailed you about it, I agree: it looked more ugly to extend the existing GET_FILTER. -Kees -- Kees Cook Pixel Security