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=-0.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_PASS,URIBL_BLOCKED autolearn=ham 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 F2A10C3279B for ; Tue, 10 Jul 2018 23:19:58 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id AADD520B6F for ; Tue, 10 Jul 2018 23:19:58 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org AADD520B6F Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=redhat.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1732348AbeGJXVR (ORCPT ); Tue, 10 Jul 2018 19:21:17 -0400 Received: from mx3-rdu2.redhat.com ([66.187.233.73]:41152 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1732291AbeGJXVR (ORCPT ); Tue, 10 Jul 2018 19:21:17 -0400 Received: from smtp.corp.redhat.com (int-mx03.intmail.prod.int.rdu2.redhat.com [10.11.54.3]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id 3393470219; Tue, 10 Jul 2018 23:19:55 +0000 (UTC) Received: from warthog.procyon.org.uk (ovpn-120-149.rdu2.redhat.com [10.10.120.149]) by smtp.corp.redhat.com (Postfix) with ESMTP id 3B386111AF0A; Tue, 10 Jul 2018 23:19:54 +0000 (UTC) Organization: Red Hat UK Ltd. Registered Address: Red Hat UK Ltd, Amberley Place, 107-111 Peascod Street, Windsor, Berkshire, SI4 1TE, United Kingdom. Registered in England and Wales under Company Registration No. 3798903 From: David Howells In-Reply-To: References: <153126248868.14533.9751473662727327569.stgit@warthog.procyon.org.uk> <153126254346.14533.14191961720018099798.stgit@warthog.procyon.org.uk> To: Casey Schaufler Cc: dhowells@redhat.com, viro@zeniv.linux.org.uk, linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-security-module@vger.kernel.org, torvalds@linux-foundation.org Subject: Re: [PATCH 08/32] smack: Implement filesystem context security hooks [ver #9] MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-ID: <16479.1531264793.1@warthog.procyon.org.uk> Date: Wed, 11 Jul 2018 00:19:53 +0100 Message-ID: <16480.1531264793@warthog.procyon.org.uk> X-Scanned-By: MIMEDefang 2.78 on 10.11.54.3 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.11.55.2]); Tue, 10 Jul 2018 23:19:55 +0000 (UTC) X-Greylist: inspected by milter-greylist-4.5.16 (mx1.redhat.com [10.11.55.2]); Tue, 10 Jul 2018 23:19:55 +0000 (UTC) for IP:'10.11.54.3' DOMAIN:'int-mx03.intmail.prod.int.rdu2.redhat.com' HELO:'smtp.corp.redhat.com' FROM:'dhowells@redhat.com' RCPT:'' Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Casey Schaufler wrote: > > Implement filesystem context security hooks for the smack LSM. > > > > Question: Should the ->fs_context_parse_source() hook be implemented to > > check the labels on any source devices specified? > > Checking the label on a block device when doing a mount > is just going to end in tears. If you're remounting from > an already mounted filesystem it might make sense to check > that the new mount doesn't provide greater access than the > existing mount. If the original mount has smackfsdefault="_" > I could see prohibiting the additional mount having > smackfsdefault="*" on a filesystem that doesn't support > xattrs. But that requires that a (hopefully) privileged > process be involved, and we expect them to have a clue. > So no, I don't see it necessary. I think I may have meant the device file rather than the actual device content. David