From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Cyrus-Session-Id: sloti22d1t05-1705864-1523175057-2-3510895286444095612 X-Sieve: CMU Sieve 3.0 X-Spam-known-sender: no X-Spam-score: 0.0 X-Spam-hits: BAYES_00 -1.9, HEADER_FROM_DIFFERENT_DOMAINS 0.25, ME_NOAUTH 0.01, RCVD_IN_DNSWL_HI -5, T_RP_MATCHES_RCVD -0.01, T_TVD_MIME_EPI 0.01, LANGUAGES en, BAYES_USED global, SA_VERSION 3.4.0 X-Spam-source: IP='209.132.180.67', Host='vger.kernel.org', Country='US', FromHeader='cz', MailFrom='org' X-Spam-charsets: plain='us-ascii' X-Attached: signature.asc X-Resolved-to: greg@kroah.com X-Delivered-to: greg@kroah.com X-Mail-from: linux-api-owner@vger.kernel.org ARC-Seal: i=1; a=rsa-sha256; cv=none; d=messagingengine.com; s=fm2; t= 1523175057; b=Yly6YPANndeqnJBpbKDm9pWPiwIXHGh2NuoD6FCnk5fI0Is8dl jhfFRglEBzjbS2WgMQFM1Z7mI5NWbcXM01W3iAdtBs8OTHUKNiezRzziCG8zT+Ab Rirfj7/jYws4Em/TirlCSqp+vM/8i52fW1BkGdGmGScldHQm6hAy3z4zL75PlvZu lEq16owncmkaJxJD5FIUeaL/15AkfXmaduQfSD90AMRISSHYxLxLKixuGOGdL2Ps lrJlWshd1EYq5dzZ6kDy3X0X8/kEkre/6fcMeey07Vy5CsXbzrotpam+dsHSFcJE P/Ena9iY8WDQOad8Q3ooihzmuuIW8bg5pqTA== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d= messagingengine.com; h=date:from:to:cc:subject:message-id :references:mime-version:content-type:in-reply-to:sender :list-id; s=fm2; t=1523175057; bh=iyxUF4l3DMTTgn2Snu+VguP4MwSOtn dsoBzIuUYTOSQ=; b=XapcfklpC6QMeHZLJ6Y+SiRIWBxBN3uVkJF5h4k/59zbtn YUZg4w0OHqjxuRnLT1iv80wPlC0q6CmH+V7tMaDktSlq6W/jIochLVg+e3gJKyB0 1KTVTGC9v5wfRJHuofPEu1ccHHzxto5+/4cZdqtxn89mFcQ7+p9rBCmQHGD8WYhr zkikQgBDFm61gW0a81xxLAvhY9laDf6Zg3zlWDcX8YLIWqnMaEDZnU3uG7zi2epb 3TyaT9WbdkWN0b1gKjY+oaxvfeklwIz64WcEmZSbMfxTqzIkEG8WNjRpHkYQgpXG kLHndI6dXnhXPMS3RrWe163d5RK0vJYUJHCPe3dA== ARC-Authentication-Results: i=1; mx4.messagingengine.com; arc=none (no signatures found); dkim=none (no signatures found); dmarc=none (p=none,has-list-id=yes,d=none) header.from=ucw.cz; iprev=pass policy.iprev=209.132.180.67 (vger.kernel.org); spf=none smtp.mailfrom=linux-api-owner@vger.kernel.org smtp.helo=vger.kernel.org; x-aligned-from=fail; x-cm=none score=0; x-ptr=pass x-ptr-helo=vger.kernel.org x-ptr-lookup=vger.kernel.org; x-return-mx=pass smtp.domain=vger.kernel.org smtp.result=pass smtp_org.domain=kernel.org smtp_org.result=pass smtp_is_org_domain=no header.domain=ucw.cz header.result=pass header_is_org_domain=yes; x-vs=clean score=-51 state=0 Authentication-Results: mx4.messagingengine.com; arc=none (no signatures found); dkim=none (no signatures found); dmarc=none (p=none,has-list-id=yes,d=none) header.from=ucw.cz; iprev=pass policy.iprev=209.132.180.67 (vger.kernel.org); spf=none smtp.mailfrom=linux-api-owner@vger.kernel.org smtp.helo=vger.kernel.org; x-aligned-from=fail; x-cm=none score=0; x-ptr=pass x-ptr-helo=vger.kernel.org x-ptr-lookup=vger.kernel.org; x-return-mx=pass smtp.domain=vger.kernel.org smtp.result=pass smtp_org.domain=kernel.org smtp_org.result=pass smtp_is_org_domain=no header.domain=ucw.cz header.result=pass header_is_org_domain=yes; x-vs=clean score=-51 state=0 X-ME-VSCategory: clean X-CM-Envelope: MS4wfFGVs2L5GcHrPvHSePtcnP3nZS8HY/DVhTSHGKUAsphPh99ckuHgcwWFmohhWTCbZo2iSHilKAhq4AfRLug00tiNNnxFWFSbC4ORU08nMY/AdO7yUf0k wmadN0yK5onqjCQZrlDNbBKSbx6HM9gheCvUy/lYWDokHNl+B2wws+CzmwFgyNY6QZe4t587lgvUM263aGcF2RSnibgcN9NLVRMHMJVPn4fhFriSHRvo4IJu X-CM-Analysis: v=2.3 cv=JLoVTfCb c=1 sm=1 tr=0 a=UK1r566ZdBxH71SXbqIOeA==:117 a=UK1r566ZdBxH71SXbqIOeA==:17 a=Kd1tUaAdevIA:10 a=Z4Rwk6OoAAAA:8 a=1XWaLZrsAAAA:8 a=M8rcC2nyAAAA:8 a=RXnXJx7MAAAA:8 a=SumpCwHsQv_Z2nZDHcgA:9 a=CjuIK1q_8ugA:10 a=0dxXHNIcbWwA:10 a=gA6IeH5FQcgA:10 a=NWVoK91CQyQA:10 a=66f2praVOus5ADcixbUA:9 a=ONNS8QRKHyMA:10 a=VwQbUJbxAAAA:8 a=fUSZZkATYxXnQMecnGkA:9 a=x8gzFH9gYPwA:10 a=HkZW87K1Qel5hWWM3VKY:22 a=K9tzwgKBnWaK51F8Cre1:22 a=U_UV0sFCMgXoaKVbI-EZ:22 a=AjGcO6oz07-iQ99wixmX:22 X-ME-CMScore: 0 X-ME-CMCategory: none Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752037AbeDHIKy (ORCPT ); Sun, 8 Apr 2018 04:10:54 -0400 Received: from atrey.karlin.mff.cuni.cz ([195.113.26.193]:59562 "EHLO atrey.karlin.mff.cuni.cz" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751826AbeDHIKw (ORCPT ); Sun, 8 Apr 2018 04:10:52 -0400 Date: Sun, 8 Apr 2018 10:10:50 +0200 From: Pavel Machek To: Matthew Garrett Cc: Linus Torvalds , luto@kernel.org, David Howells , Ard Biesheuvel , jmorris@namei.org, Alan Cox , Greg Kroah-Hartman , Linux Kernel Mailing List , jforbes@redhat.com, linux-man@vger.kernel.org, jlee@suse.com, LSM List , linux-api@vger.kernel.org, Kees Cook , linux-efi Subject: Re: [GIT PULL] Kernel lockdown for secure boot Message-ID: <20180408081050.GA4965@amd> References: <4136.1522452584@warthog.procyon.org.uk> <186aeb7e-1225-4bb8-3ff5-863a1cde86de@kernel.org> <30459.1522739219@warthog.procyon.org.uk> MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="17pEHd4RhPHOinZp" Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.23 (2014-03-12) Sender: linux-api-owner@vger.kernel.org X-Mailing-List: linux-api@vger.kernel.org X-getmail-retrieved-from-mailbox: INBOX X-Mailing-List: linux-kernel@vger.kernel.org List-ID: --17pEHd4RhPHOinZp Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Tue 2018-04-03 21:08:54, Matthew Garrett wrote: > On Tue, Apr 3, 2018 at 2:01 PM Linus Torvalds > > wrote: >=20 > > On Tue, Apr 3, 2018 at 1:54 PM, Matthew Garrett wrot= e: > > > > > >> .. maybe you don't *want* secure boot, but it's been pushed in your > > >> face by people with an agenda? > > > > > > Then turn it off, or build a self-signed kernel that doesn't do this? >=20 > > Umm. So you asked a question, and then when you got an answer you said > > "don't do that then". >=20 > > The fact is, some hardware pushes secure boot pretty hard. That has > > *nothing* to do with some "lockdown" mode. >=20 > Secure Boot ensures that the firmware will only load signed bootloaders. = If > a signed bootloader loads a kernel that's effectively an unsigned > bootloader, there's no point in using Secure Boot - you should just turn = it > off instead, because it's not giving you any meaningful > security. Andy's Not true. I have kernel with printk() enabled. Yes, once userland is started, you can boot another kernel, maybe. Maybe my kernel is locked down with exception of kexec, and it does printk(KERN_CRIT "kexecing") followed by mdelay(5000). That's pretty good security. Pavel --=20 (english) http://www.livejournal.com/~pavelmachek (cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blo= g.html --17pEHd4RhPHOinZp Content-Type: application/pgp-signature; name="signature.asc" Content-Description: Digital signature -----BEGIN PGP SIGNATURE----- Version: GnuPG v1 iEYEARECAAYFAlrJzooACgkQMOfwapXb+vJyawCgucLLA8QbmX8zLUT7nIWXw5P+ p/sAoI5s8z1MIYAXdUMjuXLq63vVHR7v =llcn -----END PGP SIGNATURE----- --17pEHd4RhPHOinZp--