Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933751AbdDERLx (ORCPT ); Wed, 5 Apr 2017 13:11:53 -0400 Received: from mx1.redhat.com ([209.132.183.28]:40330 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S933721AbdDERLY (ORCPT ); Wed, 5 Apr 2017 13:11:24 -0400 DMARC-Filter: OpenDMARC Filter v1.3.2 mx1.redhat.com 2EE0464D8E Authentication-Results: ext-mx09.extmail.prod.ext.phx2.redhat.com; dmarc=none (p=none dis=none) header.from=redhat.com Authentication-Results: ext-mx09.extmail.prod.ext.phx2.redhat.com; spf=pass smtp.mailfrom=dhowells@redhat.com DKIM-Filter: OpenDKIM Filter v2.11.0 mx1.redhat.com 2EE0464D8E 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 09/24] kexec_file: Disable at runtime if securelevel has been set From: David Howells To: linux-kernel@vger.kernel.org Cc: Matthew Garrett , dhowells@redhat.com, linux-efi@vger.kernel.org, gnomes@lxorguk.ukuu.org.uk, gregkh@linuxfoundation.org, Chun-Yi Lee , linux-security-module@vger.kernel.org, keyrings@vger.kernel.org, matthew.garrett@nebula.com Date: Wed, 05 Apr 2017 18:11:21 +0100 Message-ID: <149141228170.31282.6899985667525868658.stgit@warthog.procyon.org.uk> In-Reply-To: <149141219387.31282.6648284836568938717.stgit@warthog.procyon.org.uk> References: <149141219387.31282.6648284836568938717.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 [10.5.110.38]); Wed, 05 Apr 2017 17:11:24 +0000 (UTC) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1103 Lines: 33 From: Chun-Yi Lee When KEXEC_VERIFY_SIG is not enabled, kernel should not loads image through kexec_file systemcall if securelevel has been set. This code was showed in Matthew's patch but not in git: https://lkml.org/lkml/2015/3/13/778 Cc: Matthew Garrett Signed-off-by: Chun-Yi Lee Signed-off-by: David Howells --- kernel/kexec_file.c | 6 ++++++ 1 file changed, 6 insertions(+) diff --git a/kernel/kexec_file.c b/kernel/kexec_file.c index b118735fea9d..f6937eecd1eb 100644 --- a/kernel/kexec_file.c +++ b/kernel/kexec_file.c @@ -268,6 +268,12 @@ SYSCALL_DEFINE5(kexec_file_load, int, kernel_fd, int, initrd_fd, if (!capable(CAP_SYS_BOOT) || kexec_load_disabled) return -EPERM; + /* 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; + /* Make sure we have a legal set of flags */ if (flags != (flags & KEXEC_FILE_FLAGS)) return -EINVAL;