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=-2.2 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_PASS,URIBL_BLOCKED,USER_AGENT_MUTT autolearn=unavailable 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 67ECAC43143 for ; Mon, 1 Oct 2018 22:53:30 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 290E72089A for ; Mon, 1 Oct 2018 22:53:30 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 290E72089A Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=fromorbit.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-security-module-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726321AbeJBFde (ORCPT ); Tue, 2 Oct 2018 01:33:34 -0400 Received: from ipmail01.adl6.internode.on.net ([150.101.137.136]:49681 "EHLO ipmail01.adl6.internode.on.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725936AbeJBFde (ORCPT ); Tue, 2 Oct 2018 01:33:34 -0400 Received: from ppp59-167-129-252.static.internode.on.net (HELO dastard) ([59.167.129.252]) by ipmail01.adl6.internode.on.net with ESMTP; 02 Oct 2018 08:23:25 +0930 Received: from dave by dastard with local (Exim 4.80) (envelope-from ) id 1g7749-0006hf-6g; Tue, 02 Oct 2018 08:53:25 +1000 Date: Tue, 2 Oct 2018 08:53:25 +1000 From: Dave Chinner To: "Theodore Y. Ts'o" , Alan Cox , TongZhang , darrick.wong@oracle.com, linux-xfs@vger.kernel.org, LKML , linux-security-module@vger.kernel.org, Wenbo Shen Subject: Re: Leaking Path in XFS's ioctl interface(missing LSM check) Message-ID: <20181001225325.GJ18567@dastard> References: <5EF0D46A-C098-4B51-AD13-225FFCA35D4C@vt.edu> <20180926013329.GD31060@dastard> <20180926192426.472360ea@alans-desktop> <20180927013812.GF31060@dastard> <20180930151652.6975610c@alans-desktop> <20181001002521.GM31060@dastard> <20181001160442.47c798bc@alans-desktop> <20181001152529.GA2549@thunk.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20181001152529.GA2549@thunk.org> User-Agent: Mutt/1.5.21 (2010-09-15) Sender: owner-linux-security-module@vger.kernel.org Precedence: bulk List-ID: On Mon, Oct 01, 2018 at 11:25:29AM -0400, Theodore Y. Ts'o wrote: > On Mon, Oct 01, 2018 at 04:04:42PM +0100, Alan Cox wrote: > > > Systems restricted by LSMs to the point where CAP_SYS_ADMIN is not > > > trusted have exactly the same issues. i.e. there's nobody trusted by > > > the kernel to administer the storage stack, and nobody has defined a > > > workable security model that can prevent untrusted users from > > > violating the existing storage trust model.... > > > > With a proper set of LSM checks you can lock the filesystem management > > and enforcement to a particular set of objects. You can build that model > > where for example only an administrative login from a trusted console may > > launch processes to do that management. > > > > Or you could - if things were not going around the LSM hooks. > > It would be useful if anyone actually *wants* to do this thing to > define a formal security model, and detail *everything* that would > need to be changed in order to accomplish it. Just as we don't > speculatively add code "just in case" someone might want to use it > someday, I don't think we should be adding random LSM hooks just > becausre someone *might* want do something. Yeah, that's what I was implying we needed to do - taking the current model and slapping LSM hooks around randomly will only make things break and cause admins to curse us.... > Let's see the use case, and let's see how horrible the changes would > need to be, and how credible we think it is that someone will actually > want to *use* it. I suspect the chagnes will be a really huge number > of places, and not just in XFS.... So do I - the "in root we trust" model is pretty deeply ingrained up and down the storage stack. I also suspect that most of our hardware admin (not just storage) has similar assumptions about the security model they operate in. Cheers, Dave. -- Dave Chinner david@fromorbit.com