From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753544AbcGZC6o (ORCPT ); Mon, 25 Jul 2016 22:58:44 -0400 Received: from shards.monkeyblade.net ([184.105.139.130]:51052 "EHLO shards.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752877AbcGZC6k (ORCPT ); Mon, 25 Jul 2016 22:58:40 -0400 Date: Mon, 25 Jul 2016 19:58:36 -0700 (PDT) Message-Id: <20160725.195836.1881375122073635224.davem@davemloft.net> To: ebiederm@xmission.com Cc: containers@lists.linux-foundation.org, keescook@chromium.org, netdev@vger.kernel.org, linux-kernel@vger.kernel.org, luto@amacapital.net, seth.forshee@canonical.com, kernel@kyup.com, linux-api@vger.kernel.org, linux-fsdevel@vger.kernel.org, jann@thejh.net Subject: Re: [PATCH v2 02/10] userns: Add per user namespace sysctls. From: David Miller In-Reply-To: <87k2g95it9.fsf@x220.int.ebiederm.org> References: <878twp6zd2.fsf@x220.int.ebiederm.org> <20160725.172406.352408511647766870.davem@davemloft.net> <87k2g95it9.fsf@x220.int.ebiederm.org> X-Mailer: Mew version 6.7 on Emacs 24.5 / Mule 6.0 (HANACHIRUSATO) Mime-Version: 1.0 Content-Type: Text/Plain; charset=us-ascii Content-Transfer-Encoding: 7bit X-Greylist: Sender succeeded SMTP AUTH, not delayed by milter-greylist-4.5.12 (shards.monkeyblade.net [149.20.54.216]); Mon, 25 Jul 2016 19:58:38 -0700 (PDT) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: ebiederm@xmission.com (Eric W. Biederman) Date: Mon, 25 Jul 2016 19:44:50 -0500 > User namespaces have enabled unprivileged users access to a lot more > data structures and so to catch programs that go crazy we need a lot > more limits. I believe some of those limits make sense per namespace. > As it is easy in some cases to say any more than Y number of those > per namespace is excessive. For example a limit of 1,000,000 ipv4 > routes per network namespaces is a sanity check as there are > currently 621,649 ipv4 prefixes advertized in bgp. When we give a new namespace to unprivileged users, we honestly should make the sysctl settings we give to them become "limits". They can further constrain the sysctl settings but may not raise them.