From patchwork Mon Oct 23 16:43:01 2017 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "Bruno E. O. Meneguele" X-Patchwork-Id: 10022851 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork.web.codeaurora.org (Postfix) with ESMTP id CDF8E603FA for ; Mon, 23 Oct 2017 16:44:12 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id BEBBC286B2 for ; Mon, 23 Oct 2017 16:44:12 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id B33B3288B6; Mon, 23 Oct 2017 16:44:12 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-6.9 required=2.0 tests=BAYES_00,RCVD_IN_DNSWL_HI autolearn=unavailable version=3.3.1 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 73A56288AC for ; Mon, 23 Oct 2017 16:44:12 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751640AbdJWQnO (ORCPT ); Mon, 23 Oct 2017 12:43:14 -0400 Received: from mx1.redhat.com ([209.132.183.28]:55442 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751357AbdJWQnM (ORCPT ); Mon, 23 Oct 2017 12:43:12 -0400 Received: from smtp.corp.redhat.com (int-mx05.intmail.prod.int.phx2.redhat.com [10.5.11.15]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id 31257806B0; Mon, 23 Oct 2017 16:43:12 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mx1.redhat.com 31257806B0 Authentication-Results: ext-mx02.extmail.prod.ext.phx2.redhat.com; dmarc=none (p=none dis=none) header.from=redhat.com Authentication-Results: ext-mx02.extmail.prod.ext.phx2.redhat.com; spf=fail smtp.mailfrom=brdeoliv@redhat.com Received: from glitch.redhat.com (ovpn-116-32.gru2.redhat.com [10.97.116.32]) by smtp.corp.redhat.com (Postfix) with ESMTP id DF94C7C01D; Mon, 23 Oct 2017 16:43:09 +0000 (UTC) From: "Bruno E. O. Meneguele" To: linux-kernel@vger.kernel.org Cc: linux-security-module@vger.kernel.org, linux-integrity@vger.kernel.org, serge@hallyn.com, james.l.morris@oracle.com, dmitry.kasatkin@gmail.com, zohar@linux.vnet.ibm.com, rusty@rustcorp.com.au, jeyu@kernel.org Subject: [PATCH v2 1/2] module: export module signature enforcement status Date: Mon, 23 Oct 2017 14:43:01 -0200 Message-Id: <52c9c671996c472db9112affbbecfabfab09bad8.1508776704.git.brdeoliv@redhat.com> In-Reply-To: References: X-Scanned-By: MIMEDefang 2.79 on 10.5.11.15 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.26]); Mon, 23 Oct 2017 16:43:12 +0000 (UTC) Sender: linux-integrity-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-integrity@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP A static variable sig_enforce is used as status var to indicate the real value of CONFIG_MODULE_SIG_FORCE, once this one is set the var will hold true, but if the CONFIG is not set the status var will hold whatever value is present in the module.sig_enforce kernel cmdline param: true when =1 and false when =0 or not present. Considering this cmdline param take place over the CONFIG value when it's not set, other places in the kernel could misbehave since they would have only the CONFIG_MODULE_SIG_FORCE value to rely on. Exporting this status var allows the kernel to rely in the effective value of module signature enforcement, being it from CONFIG value or cmdline param. Signed-off-by: Bruno E. O. Meneguele --- include/linux/module.h | 2 ++ kernel/module.c | 10 ++++++++++ 2 files changed, 12 insertions(+) diff --git a/include/linux/module.h b/include/linux/module.h index fe5aa3736707..ddfe17e3a85c 100644 --- a/include/linux/module.h +++ b/include/linux/module.h @@ -806,4 +806,6 @@ static inline bool module_sig_ok(struct module *module) } #endif /* CONFIG_MODULE_SIG */ +bool is_module_sig_enforced(void); + #endif /* _LINUX_MODULE_H */ diff --git a/kernel/module.c b/kernel/module.c index de66ec825992..d1c194b057a2 100644 --- a/kernel/module.c +++ b/kernel/module.c @@ -278,6 +278,16 @@ static bool sig_enforce = IS_ENABLED(CONFIG_MODULE_SIG_FORCE); module_param(sig_enforce, bool_enable_only, 0644); #endif /* !CONFIG_MODULE_SIG_FORCE */ +/* + * Export sig_enforce kernel cmdline parameter to allow other subsystems rely + * on that instead of directly to CONFIG_MODULE_SIG_FORCE config. + */ +bool is_module_sig_enforced(void) +{ + return sig_enforce; +} +EXPORT_SYMBOL(is_module_sig_enforced); + /* Block module loading/unloading? */ int modules_disabled = 0; core_param(nomodule, modules_disabled, bint, 0);