From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S966020AbeBMWTx (ORCPT ); Tue, 13 Feb 2018 17:19:53 -0500 Received: from mout.kundenserver.de ([212.227.17.10]:34941 "EHLO mout.kundenserver.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S965900AbeBMWTw (ORCPT ); Tue, 13 Feb 2018 17:19:52 -0500 Subject: Re: plan9 semantics on Linux - mount namespaces From: Enrico Weigelt To: "linux-kernel@vger.kernel.org" References: <0f058286-a432-379b-f559-f2fe713807ab@metux.net> Cc: Linux Containers Organization: metux IT consult Message-ID: <5633d335-3926-d98f-d6d7-948b1e2a0b2c@metux.net> Date: Tue, 13 Feb 2018 22:19:48 +0000 User-Agent: Mozilla/5.0 (X11; Linux i686; rv:52.0) Gecko/20100101 Thunderbird/52.4.0 MIME-Version: 1.0 In-Reply-To: <0f058286-a432-379b-f559-f2fe713807ab@metux.net> Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 8bit X-Provags-ID: V03:K0:t4V4fBdWLi707Vf0/ed0i+UM0+tnOr6yYKHUHr7chLmRwbVaavY R7k3zYGG/3sfaMsXvgEMQgJrLJVsTw1NtB39EpVaYoYSsllhUTLJXDx59h/7IfCX4sJMF+C 9I/aAs5dvA1c2VafEUQh9FMfh9u4uKwwZUA/kfEY9V1ySZi06JHUTIx+xMR1nQ6ApH9CsJU 428KXdboQEqHPMiMJww+w== X-UI-Out-Filterresults: notjunk:1;V01:K0:TGf9kgR1LeU=:hkj5QF3meZvVB0WAAVp3la DrEmqA1OsdAEFAFNzXGsgJzt84EdtWLZmrnkRYJO3JGhzBVj/Dm9yR9d/p+FoXaGeoqExVcEX Lf2NXGQMpmhykerLPZVb5rLtQmndWsvQL8RjkUVlVpEtSHZitq9tYg1mCrGV9/BT+CekZNNNS L+FLhe0V0AlGDVYj/MSFZeruEUqZxO56d82sOsWKOyiqVmSa42rKfHDIFDbEOL+SwtEoCNNRH RmOk+EqUcobmfybuX8Jqo40YiKav0z8RN6VKqucfNeFTvvBgIzOYY9Fen0FnZnfwZsxkPIG+7 WTx861/KrZbkUknIkKLkRawoJfPMyNdfeSgX7GySOD4ZiOL2RC4yt0YTvpOudiTT5MgmY/3tM KT9l4RzXMvOdIN++yBrwOjuULFd5UV9pwz2CWxXgwSxKEwqUXJvhVP4ZZdVHk2+U18jf94Eo+ 0VxksU1kMpzot7APP9vF3OkXe+ciSV8AgtMewSXaZ31xTwUKP7dHwW6lrDFdByCJcn7/iqzQo fbFR/LW9Xcgz1Ca//GPgoC8f+ytaJEPQDlFymM9m5/MYD0CcNjxnVCO7RNYDV/gUNcIUn6iIK O6iH13LDDonY2AHHVij9RpHvUHZqnvxjjVrrqqmmO4HQmDlQf2Ay0/cyWgJGwxtbr4qnp6wPR vd1For8s51agjJgSkwNs+nBGxvKj3YI0j8KPsVz3Jz3RDV8ppPg7tEbdODlrF/mAX/DpYTqcH YjodZrwO4AyDnIBQFKqaIYBsnWRyWStRmsg//MxKtQoNonQJNwey/XopJr8= Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 13.02.2018 22:12, Enrico Weigelt wrote: CC @containers@lists.linux-foundation.org > Hi folks, > > > I'm currently trying to implement plan9 semantics on Linux and > yet sorting out how to do the mount namespace handling. > > On plan9, any unprivileged process can create its own namespace > and mount/bind at will, while on Linux this requires CAP_SYS_ADMIN. > > What is the reason for not allowing arbitrary users to create their > own private mount namespace ? What could go wrong here ? > > IMHO, we could allow mount/bind under the following conditions: > > * the process is in a private mount namespace > * no suid-flag is honored (either force all mounts to nosuid or >   completely mask it out) > * only certain whitelisted filesystems allowed (eg. 9P and FUSE) > > Maybe that all could be enabled by a new capability. > > > any suggestions ? > > > --mtx > -- Enrico Weigelt, metux IT consult Free software and Linux embedded engineering info@metux.net -- +49-151-27565287