From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-0.9 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE, SPF_PASS autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 831DCC5DF60 for ; Fri, 8 Nov 2019 16:19:56 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 52B7321882 for ; Fri, 8 Nov 2019 16:19:56 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="dXccqiy5" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726741AbfKHQT4 (ORCPT ); Fri, 8 Nov 2019 11:19:56 -0500 Received: from us-smtp-1.mimecast.com ([205.139.110.61]:56087 "EHLO us-smtp-delivery-1.mimecast.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1726152AbfKHQTz (ORCPT ); Fri, 8 Nov 2019 11:19:55 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1573229994; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=qfftxBQSyIyxsP98Stgtia4lPdR8+21Ca93caRxOvvM=; b=dXccqiy5Gxo4+VxfXYIEh3exarron01zzjyObiY3U89AwJ2oV9uAX8XW7D/ioP3lwdwOoE /carE5lHjuHm9IsvmlpXhtmlIkuG4ln2+rvdkQRG7svK245UnuEzmV+7ZAkvKh9V+6ByPz IT6LQVcHZHAnSjzDvjiLlbT4gfKhZIg= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-48-8AWStgtsMxKyhFvI6GLfwg-1; Fri, 08 Nov 2019 11:19:51 -0500 Received: from smtp.corp.redhat.com (int-mx07.intmail.prod.int.phx2.redhat.com [10.5.11.22]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 77E7A107ACC5; Fri, 8 Nov 2019 16:19:50 +0000 (UTC) Received: from oldenburg2.str.redhat.com (dhcp-192-200.str.redhat.com [10.33.192.200]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 535161001B39; Fri, 8 Nov 2019 16:19:49 +0000 (UTC) From: Florian Weimer To: Szabolcs Nagy Cc: Adhemerval Zanella , "libc-alpha\@sourceware.org" , nd , linux-man Subject: Re: glibc in master is incompatible with systemd-nspawn References: <87k18a62xe.fsf@oldenburg2.str.redhat.com> <20191108141149.GB20533@altlinux.org> <87v9ru1l6d.fsf@oldenburg2.str.redhat.com> Date: Fri, 08 Nov 2019 17:19:47 +0100 In-Reply-To: (Szabolcs Nagy's message of "Fri, 8 Nov 2019 16:01:58 +0000") Message-ID: <874kze1gt8.fsf@oldenburg2.str.redhat.com> User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/26.2 (gnu/linux) MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.84 on 10.5.11.22 X-MC-Unique: 8AWStgtsMxKyhFvI6GLfwg-1 X-Mimecast-Spam-Score: 0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: quoted-printable Sender: linux-man-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-man@vger.kernel.org * Szabolcs Nagy: > it's of course broken whenever the application is > run on a newer kernel+libc than what was used for > creating the filter, may be the seccomp manual should > warn against the use of EPERM (there is already a > caveats section)? On this topic (ENOSYS vs PERM), I wrote earlier today: | They serve different purposes. EPERM is appropriate if you want things | to fail (so that applications break), ENOSYS is appropriate if you | want to trigger fallback (like utimensat_time64 =E2=86=92 utime) or just | disable the feature (because the application assumes the kernel is too | old to support it). For a generic container runtime, there either have | to be no filters by default (my preference), or filters for unknown | system calls need to return ENOSYS. Everything else will break too | many applications. | | If you have specific knowledge of the system call, you can return | EPERM instead in a few cases (e.g. for clock_settime). But that's not | really possible for an unknown system call. I don't know how controversial this position is. People seem rather opinionated about EPERM. Thanks, Florian