From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754097AbdDGHII convert rfc822-to-8bit (ORCPT ); Fri, 7 Apr 2017 03:08:08 -0400 Received: from mx1.redhat.com ([209.132.183.28]:52434 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753070AbdDGHIB (ORCPT ); Fri, 7 Apr 2017 03:08:01 -0400 DMARC-Filter: OpenDMARC Filter v1.3.2 mx1.redhat.com CB4B783F47 Authentication-Results: ext-mx03.extmail.prod.ext.phx2.redhat.com; dmarc=none (p=none dis=none) header.from=redhat.com Authentication-Results: ext-mx03.extmail.prod.ext.phx2.redhat.com; spf=pass smtp.mailfrom=dhowells@redhat.com DKIM-Filter: OpenDKIM Filter v2.11.0 mx1.redhat.com CB4B783F47 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: <20170407061935.GB10100@dhcp-128-65.nay.redhat.com> References: <20170407061935.GB10100@dhcp-128-65.nay.redhat.com> <149142326734.5101.4596394505987813763.stgit@warthog.procyon.org.uk> <149142335441.5101.2294976563846442575.stgit@warthog.procyon.org.uk> <20170407030545.GA4296@dhcp-128-65.nay.redhat.com> <1491536950.4184.10.camel@linux.vnet.ibm.com> To: Dave Young Cc: dhowells@redhat.com, Mimi Zohar , linux-kernel@vger.kernel.org, Matthew Garrett , linux-efi@vger.kernel.org, gnomes@lxorguk.ukuu.org.uk, Chun-Yi Lee , gregkh@linuxfoundation.org, kexec@lists.infradead.org, linux-security-module@vger.kernel.org, keyrings@vger.kernel.org, matthew.garrett@nebula.com Subject: Re: [PATCH 09/24] kexec_file: Disable at runtime if securelevel has been set MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 8BIT Date: Fri, 07 Apr 2017 08:07:55 +0100 Message-ID: <21418.1491548875@warthog.procyon.org.uk> X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.27]); Fri, 07 Apr 2017 07:08:01 +0000 (UTC) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Dave Young wrote: > > > > + /* Don't permit images to be loaded into trusted kernels if we're not > > > > + * going to verify the signature on them > > > > + */ > > > > + if (!IS_ENABLED(CONFIG_KEXEC_VERIFY_SIG) && kernel_is_locked_down()) > > > > + return -EPERM; > > > > + > > > > > > > > IMA can be used to verify file signatures too, based on the LSM hooks > > in  kernel_read_file_from_fd().  CONFIG_KEXEC_VERIFY_SIG should not be > > required. > > Mimi, I remember we talked somthing before about the two signature > verification. One can change IMA policy in initramfs userspace, > also there are kernel cmdline param to disable IMA, so it can break the > lockdown? Suppose kexec boot with ima disabled cmdline param and then > kexec reboot again.. I guess I should lock down the parameter to disable IMA too. David