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=-1.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED 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 6AC96C433DF for ; Thu, 2 Jul 2020 19:04:42 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 5014420702 for ; Thu, 2 Jul 2020 19:04:42 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726206AbgGBTEk (ORCPT ); Thu, 2 Jul 2020 15:04:40 -0400 Received: from out03.mta.xmission.com ([166.70.13.233]:51372 "EHLO out03.mta.xmission.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725878AbgGBTEk (ORCPT ); Thu, 2 Jul 2020 15:04:40 -0400 Received: from in02.mta.xmission.com ([166.70.13.52]) by out03.mta.xmission.com with esmtps (TLS1.2:ECDHE_RSA_AES_128_GCM_SHA256:128) (Exim 4.90_1) (envelope-from ) id 1jr4Vg-0000Na-3K; Thu, 02 Jul 2020 13:04:36 -0600 Received: from ip68-227-160-95.om.om.cox.net ([68.227.160.95] helo=x220.xmission.com) by in02.mta.xmission.com with esmtpsa (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.87) (envelope-from ) id 1jr4Ve-00069I-03; Thu, 02 Jul 2020 13:04:35 -0600 From: ebiederm@xmission.com (Eric W. Biederman) To: Matt Bennett Cc: netdev@vger.kernel.org, zbr@ioremap.net, linux-kernel@vger.kernel.org, Linux Containers References: <20200702002635.8169-1-matt.bennett@alliedtelesis.co.nz> Date: Thu, 02 Jul 2020 13:59:59 -0500 In-Reply-To: <20200702002635.8169-1-matt.bennett@alliedtelesis.co.nz> (Matt Bennett's message of "Thu, 2 Jul 2020 12:26:30 +1200") Message-ID: <87k0zlspxs.fsf@x220.int.ebiederm.org> User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/26.1 (gnu/linux) MIME-Version: 1.0 Content-Type: text/plain X-XM-SPF: eid=1jr4Ve-00069I-03;;;mid=<87k0zlspxs.fsf@x220.int.ebiederm.org>;;;hst=in02.mta.xmission.com;;;ip=68.227.160.95;;;frm=ebiederm@xmission.com;;;spf=neutral X-XM-AID: U2FsdGVkX1/cThDAnv+o2eEuqq0eobQSsw98Xk5vfJg= X-SA-Exim-Connect-IP: 68.227.160.95 X-SA-Exim-Mail-From: ebiederm@xmission.com Subject: Re: [PATCH 0/5] RFC: connector: Add network namespace awareness X-SA-Exim-Version: 4.2.1 (built Thu, 05 May 2016 13:38:54 -0600) X-SA-Exim-Scanned: Yes (on in02.mta.xmission.com) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Matt Bennett writes: > Previously the connector functionality could only be used by processes running in the > default network namespace. This meant that any process that uses the connector functionality > could not operate correctly when run inside a container. This is a draft patch series that > attempts to now allow this functionality outside of the default network namespace. > > I see this has been discussed previously [1], but am not sure how my changes relate to all > of the topics discussed there and/or if there are any unintended side > effects from my draft In a quick skim this patchset does not look like it approaches a correct conversion to having code that works in multiple namespaces. I will take the changes to proc_id_connector for example. You report the values in the callers current namespaces. Which means an unprivileged user can create a user namespace and get connector to report whichever ids they want to users in another namespace. AKA lie. So this appears to make connector completely unreliable. Eric > changes. > > Thanks. > > [1] https://marc.info/?l=linux-kernel&m=150806196728365&w=2 > > Matt Bennett (5): > connector: Use task pid helpers > connector: Use 'current_user_ns' function > connector: Ensure callback entry is released > connector: Prepare for supporting multiple namespaces > connector: Create connector per namespace > > Documentation/driver-api/connector.rst | 6 +- > drivers/connector/cn_proc.c | 110 +++++++------- > drivers/connector/cn_queue.c | 9 +- > drivers/connector/connector.c | 192 ++++++++++++++++++++----- > drivers/hv/hv_fcopy.c | 1 + > drivers/hv/hv_utils_transport.c | 6 +- > drivers/md/dm-log-userspace-transfer.c | 6 +- > drivers/video/fbdev/uvesafb.c | 8 +- > drivers/w1/w1_netlink.c | 19 +-- > include/linux/connector.h | 38 +++-- > include/net/net_namespace.h | 4 + > kernel/exit.c | 2 +- > samples/connector/cn_test.c | 6 +- > 13 files changed, 286 insertions(+), 121 deletions(-)