From patchwork Wed Nov 16 21:47:38 2016 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: David Howells X-Patchwork-Id: 9432803 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 5FC7060471 for ; Wed, 16 Nov 2016 21:48:07 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 1AA8A223A4 for ; Wed, 16 Nov 2016 21:48:07 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 095DC1FF1E; Wed, 16 Nov 2016 21:48:07 +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=ham 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 88FE22915D for ; Wed, 16 Nov 2016 21:48:06 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S936601AbcKPVrz (ORCPT ); Wed, 16 Nov 2016 16:47:55 -0500 Received: from mx1.redhat.com ([209.132.183.28]:50478 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S936132AbcKPVrl (ORCPT ); Wed, 16 Nov 2016 16:47:41 -0500 Received: from int-mx10.intmail.prod.int.phx2.redhat.com (int-mx10.intmail.prod.int.phx2.redhat.com [10.5.11.23]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id 9D3C2635E2; Wed, 16 Nov 2016 21:47:40 +0000 (UTC) Received: from warthog.procyon.org.uk (ovpn-116-110.phx2.redhat.com [10.3.116.110]) by int-mx10.intmail.prod.int.phx2.redhat.com (8.14.4/8.14.4) with ESMTP id uAGLlcUG015401; Wed, 16 Nov 2016 16:47:39 -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 03/16] efi: Disable secure boot if shim is in insecure mode From: David Howells To: keyrings@vger.kernel.org Cc: matthew.garrett@nebula.com, linux-efi@vger.kernel.org, linux-kernel@vger.kernel.org, dhowells@redhat.com, linux-security-module@vger.kernel.org, Josh Boyer Date: Wed, 16 Nov 2016 21:47:38 +0000 Message-ID: <147933285855.19316.13896885410459473517.stgit@warthog.procyon.org.uk> In-Reply-To: <147933283664.19316.12454053022687659937.stgit@warthog.procyon.org.uk> References: <147933283664.19316.12454053022687659937.stgit@warthog.procyon.org.uk> User-Agent: StGit/0.17.1-dirty MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.68 on 10.5.11.23 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.39]); Wed, 16 Nov 2016 21:47:40 +0000 (UTC) Sender: owner-linux-security-module@vger.kernel.org Precedence: bulk List-ID: X-Virus-Scanned: ClamAV using ClamSMTP From: Josh Boyer A user can manually tell the shim boot loader to disable validation of images it loads. When a user does this, it creates a UEFI variable called MokSBState that does not have the runtime attribute set. Given that the user explicitly disabled validation, we can honor that and not enable secure boot mode if that variable is set. Signed-off-by: Josh Boyer Signed-off-by: David Howells --- arch/x86/boot/compressed/eboot.c | 20 +++++++++++++++++++- 1 file changed, 19 insertions(+), 1 deletion(-) -- To unsubscribe from this list: send the line "unsubscribe linux-security-module" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html diff --git a/arch/x86/boot/compressed/eboot.c b/arch/x86/boot/compressed/eboot.c index 17b376596c96..2729a3844673 100644 --- a/arch/x86/boot/compressed/eboot.c +++ b/arch/x86/boot/compressed/eboot.c @@ -540,8 +540,9 @@ static void setup_efi_pci(struct boot_params *params) static int get_secure_boot(void) { - u8 sb, setup; + u8 sb, setup, moksbstate; unsigned long datasize = sizeof(sb); + u32 attr; efi_guid_t var_guid = EFI_GLOBAL_VARIABLE_GUID; efi_status_t status; @@ -565,6 +566,23 @@ static int get_secure_boot(void) if (setup == 1) return 0; + /* See if a user has put shim into insecure_mode. If so, and the variable + * doesn't have the runtime attribute set, we might as well honor that. + */ + var_guid = EFI_SHIM_LOCK_GUID; + status = efi_early->call((unsigned long)sys_table->runtime->get_variable, + L"MokSBState", &var_guid, &attr, &datasize, + &moksbstate); + + /* If it fails, we don't care why. Default to secure */ + if (status != EFI_SUCCESS) + return 1; + + if (!(attr & EFI_VARIABLE_RUNTIME_ACCESS)) { + if (moksbstate == 1) + return 0; + } + return 1; }