From patchwork Tue Oct 24 17:37:00 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: 10025197 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 5334F60375 for ; Tue, 24 Oct 2017 17:37:30 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 5193F285EA for ; Tue, 24 Oct 2017 17:37:30 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 466E528A52; Tue, 24 Oct 2017 17:37:30 +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 026B2285EA for ; Tue, 24 Oct 2017 17:37:29 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751477AbdJXRh1 (ORCPT ); Tue, 24 Oct 2017 13:37:27 -0400 Received: from mx1.redhat.com ([209.132.183.28]:54592 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751792AbdJXRhP (ORCPT ); Tue, 24 Oct 2017 13:37:15 -0400 Received: from smtp.corp.redhat.com (int-mx03.intmail.prod.int.phx2.redhat.com [10.5.11.13]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id 957E8C059722; Tue, 24 Oct 2017 17:37:14 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mx1.redhat.com 957E8C059722 Authentication-Results: ext-mx08.extmail.prod.ext.phx2.redhat.com; dmarc=none (p=none dis=none) header.from=redhat.com Authentication-Results: ext-mx08.extmail.prod.ext.phx2.redhat.com; spf=fail smtp.mailfrom=brdeoliv@redhat.com Received: from glitch.redhat.com (ovpn-116-16.gru2.redhat.com [10.97.116.16]) by smtp.corp.redhat.com (Postfix) with ESMTP id 531276BF75; Tue, 24 Oct 2017 17:37:12 +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 v3 1/2] module: export module signature enforcement status Date: Tue, 24 Oct 2017 15:37:00 -0200 Message-Id: In-Reply-To: References: X-Scanned-By: MIMEDefang 2.79 on 10.5.11.13 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.32]); Tue, 24 Oct 2017 17:37:14 +0000 (UTC) Sender: owner-linux-security-module@vger.kernel.org Precedence: bulk List-ID: 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 | 7 +++++++ kernel/module.c | 10 ++++++++++ 2 files changed, 17 insertions(+) diff --git a/include/linux/module.h b/include/linux/module.h index fe5aa3736707..c69b49abe877 100644 --- a/include/linux/module.h +++ b/include/linux/module.h @@ -639,6 +639,8 @@ static inline bool is_livepatch_module(struct module *mod) } #endif /* CONFIG_LIVEPATCH */ +bool is_module_sig_enforced(void); + #else /* !CONFIG_MODULES... */ static inline struct module *__module_address(unsigned long addr) @@ -753,6 +755,11 @@ static inline bool module_requested_async_probing(struct module *module) return false; } +static inline bool is_module_sig_enforced(void) +{ + return false; +} + #endif /* CONFIG_MODULES */ #ifdef CONFIG_SYSFS 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);