From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752072AbeBAVwE (ORCPT ); Thu, 1 Feb 2018 16:52:04 -0500 Received: from mx0b-001b2d01.pphosted.com ([148.163.158.5]:59048 "EHLO mx0a-001b2d01.pphosted.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1751826AbeBAVv7 (ORCPT ); Thu, 1 Feb 2018 16:51:59 -0500 Subject: Re: [RFC PATCH] rootfs: force mounting rootfs as tmpfs From: Mimi Zohar To: Rob Landley , Arvind Sankar Cc: initramfs , Taras Kondratiuk , Victor Kamensky , linux-security-module , Al Viro , linux-kernel Date: Thu, 01 Feb 2018 16:51:52 -0500 In-Reply-To: <875e5d2d-9ffe-14ab-090a-4a9632af0f35@landley.net> References: <1517348777.3469.5.camel@linux.vnet.ibm.com> <1814af5c-170d-39c0-58fd-02eb7216e008@landley.net> <1517436423.3469.237.camel@linux.vnet.ibm.com> <20180201020331.GA3774@rani.riverdale> <1517458921.3329.2.camel@linux.vnet.ibm.com> <1517500500.3974.45.camel@linux.vnet.ibm.com> <875e5d2d-9ffe-14ab-090a-4a9632af0f35@landley.net> Content-Type: text/plain; charset="UTF-8" X-Mailer: Evolution 3.20.5 (3.20.5-1.fc24) Mime-Version: 1.0 Content-Transfer-Encoding: 8bit X-TM-AS-GCONF: 00 x-cbid: 18020121-0040-0000-0000-0000040B7F40 X-IBM-AV-DETECTION: SAVI=unused REMOTE=unused XFE=unused x-cbparentid: 18020121-0041-0000-0000-0000260F215D Message-Id: <1517521912.3619.0.camel@linux.vnet.ibm.com> X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10432:,, definitions=2018-02-01_06:,, signatures=0 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 priorityscore=1501 malwarescore=0 suspectscore=3 phishscore=0 bulkscore=0 spamscore=0 clxscore=1015 lowpriorityscore=0 impostorscore=0 adultscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1709140000 definitions=main-1802010264 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, 2018-02-01 at 11:09 -0600, Rob Landley wrote: > On 02/01/2018 09:55 AM, Mimi Zohar wrote: > > On Thu, 2018-02-01 at 09:20 -0600, Rob Landley wrote: > > > >>> With your patch and specifying "root=tmpfs", dracut is complaining: > >>> > >>> dracut: FATAL: Don't know how to handle 'root=tmpfs' > >>> dracut: refusing to continue > >> > >> [googles]... I do not understand why this package exists. > >> > >> If you're switching to another root filesystem, using a tool that > >> wikipedia[citation needed] says has no purpose but to switch to another > >> root filesystem, (so let's reproduce the kernel infrastructure in > >> userspace while leaving it the kernel too)... why do you need initramfs > >> to be tmpfs? You're using it for half a second, then discarding it, > >> what's the point of it being tmpfs? > > > > Unlike the kernel image which is signed by the distros, the initramfs > > doesn't come signed, because it is built on the target system.  Even > > if the initramfs did come signed, it is beneficial to measure and > > appraise the individual files in the initramfs. > > You can still shoot yourself in the foot with tmpfs. People mount a /run > and a /tmp and then as a normal user you can go > https://twitter.com/landley/status/959103235305951233 and maybe the > default should be a little more clever there... > > I'll throw it on the todo heap. :) > > >> Sigh. If people are ok with having rootfs just be tmpfs whenever tmpfs > >> is configured in, even when you're then going to overmount it with > >> something else like you're doing, let's just _remove_ the test. If it > >> can be tmpfs, have it be tmpfs. > > > > Very much appreciated! > > Not yet tested, but something like the attached? (Sorry for the > half-finished doc changes in there, I'm at work and have a 5 minute > break. I can test properly this evening if you don't get to it...) Yes, rootfs is being mounted as tmpfs. Mimi