From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S964998AbdKBVlc (ORCPT ); Thu, 2 Nov 2017 17:41:32 -0400 Received: from mx0b-001b2d01.pphosted.com ([148.163.158.5]:58696 "EHLO mx0a-001b2d01.pphosted.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S964829AbdKBVl3 (ORCPT ); Thu, 2 Nov 2017 17:41:29 -0400 Subject: Re: [PATCH 03/27] Enforce module signatures if the kernel is locked down From: Mimi Zohar To: David Howells Cc: linux-security-module@vger.kernel.org, gnomes@lxorguk.ukuu.org.uk, linux-efi@vger.kernel.org, matthew.garrett@nebula.com, gregkh@linuxfoundation.org, linux-kernel@vger.kernel.org, jforbes@redhat.com Date: Thu, 02 Nov 2017 17:41:21 -0400 In-Reply-To: <12321.1509658211@warthog.procyon.org.uk> References: <1509650031.3507.20.camel@linux.vnet.ibm.com> <1509130095.3716.13.camel@linux.vnet.ibm.com> <150842463163.7923.11081723749106843698.stgit@warthog.procyon.org.uk> <150842465546.7923.6762214527898273559.stgit@warthog.procyon.org.uk> <20240.1509643356@warthog.procyon.org.uk> <12321.1509658211@warthog.procyon.org.uk> Content-Type: text/plain; charset="UTF-8" X-Mailer: Evolution 3.20.5 (3.20.5-1.fc24) Mime-Version: 1.0 Content-Transfer-Encoding: 8bit X-TM-AS-GCONF: 00 x-cbid: 17110221-0040-0000-0000-00000409EBA1 X-IBM-AV-DETECTION: SAVI=unused REMOTE=unused XFE=unused x-cbparentid: 17110221-0041-0000-0000-000020AC7991 Message-Id: <1509658881.3416.10.camel@linux.vnet.ibm.com> X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10432:,, definitions=2017-11-02_07:,, signatures=0 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 priorityscore=1501 malwarescore=0 suspectscore=0 phishscore=0 bulkscore=0 spamscore=0 clxscore=1015 lowpriorityscore=0 impostorscore=0 adultscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1707230000 definitions=main-1711020266 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, 2017-11-02 at 21:30 +0000, David Howells wrote: > Mimi Zohar wrote: > > > By this point, IMA-appraisal has already verified the kernel module > > signature back in kernel_read_file_from_fd(), if it was required. > >  Having a key with which to verify the appended signature or requiring > > an appended signature, should not be required as well. > > I guess I don't need to put in any support for IMA here, then, and you've > taken care of it in your patchset such that it won't actually go into > module_sig_check() in that case (or will at least return immediately). Right, it would never get here if the IMA signature verification fails.  If sig_enforce is not enabled, then it will also work.  So the only case is if sig_enforced is enabled and there is no key. eg.          else if (can_do_ima_check && is_ima_appraise_enabled())                 err = 0; Mimi