Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S934371AbcLAMeZ (ORCPT ); Thu, 1 Dec 2016 07:34:25 -0500 Received: from mx1.redhat.com ([209.132.183.28]:32854 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S934316AbcLAMeV (ORCPT ); Thu, 1 Dec 2016 07:34:21 -0500 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 Subject: [PATCH 35/39] Annotate hardware config module parameters in fs/pstore/ From: David Howells To: linux-kernel@vger.kernel.org Cc: gnomes@lxorguk.ukuu.org.uk, Tony Luck , Kees Cook , minyard@acm.org, Anton Vorontsov , dhowells@redhat.com, linux-security-module@vger.kernel.org, keyrings@vger.kernel.org, Colin Cross Date: Thu, 01 Dec 2016 12:34:18 +0000 Message-ID: <148059565828.31612.9999712213249376134.stgit@warthog.procyon.org.uk> In-Reply-To: <148059537897.31612.9461043954611464597.stgit@warthog.procyon.org.uk> References: <148059537897.31612.9461043954611464597.stgit@warthog.procyon.org.uk> User-Agent: StGit/0.17.1-dirty MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.30]); Thu, 01 Dec 2016 12:34:21 +0000 (UTC) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1892 Lines: 44 When the kernel is running in secure boot mode, we lock down the kernel to prevent userspace from modifying the running kernel image. Whilst this includes prohibiting access to things like /dev/mem, it must also prevent access by means of configuring driver modules in such a way as to cause a device to access or modify the kernel image. To this end, annotate module_param* statements that refer to hardware configuration and indicate for future reference what type of parameter they specify. The parameter parser in the core sees this information and can skip such parameters with an error message if the kernel is locked down. The module initialisation then runs as normal, but just sees whatever the default values for those parameters is. Note that we do still need to do the module initialisation because some drivers have viable defaults set in case parameters aren't specified and some drivers support automatic configuration (e.g. PNP or PCI) in addition to manually coded parameters. This patch annotates drivers in fs/pstore/. Suggested-by: One Thousand Gnomes Signed-off-by: David Howells cc: Anton Vorontsov cc: Colin Cross cc: Kees Cook cc: Tony Luck --- fs/pstore/ram.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/fs/pstore/ram.c b/fs/pstore/ram.c index 6ad831b9d1b8..37e5a265b03d 100644 --- a/fs/pstore/ram.c +++ b/fs/pstore/ram.c @@ -58,7 +58,7 @@ module_param_named(pmsg_size, ramoops_pmsg_size, ulong, 0400); MODULE_PARM_DESC(pmsg_size, "size of user space message log"); static unsigned long long mem_address; -module_param(mem_address, ullong, 0400); +module_param_hw(mem_address, ullong, other, 0400); MODULE_PARM_DESC(mem_address, "start of reserved RAM used to store oops/panic logs");