Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753899AbdDGDtd (ORCPT ); Thu, 6 Apr 2017 23:49:33 -0400 Received: from mx0a-001b2d01.pphosted.com ([148.163.156.1]:42642 "EHLO mx0a-001b2d01.pphosted.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752486AbdDGDt0 (ORCPT ); Thu, 6 Apr 2017 23:49:26 -0400 Subject: Re: [PATCH 09/24] kexec_file: Disable at runtime if securelevel has been set From: Mimi Zohar To: Dave Young , David Howells Cc: linux-kernel@vger.kernel.org, Matthew Garrett , linux-efi@vger.kernel.org, gnomes@lxorguk.ukuu.org.uk, Chun-Yi Lee , gregkh@linuxfoundation.org, kexec@lists.infradead.org, linux-security-module@vger.kernel.org, keyrings@vger.kernel.org, matthew.garrett@nebula.com Date: Thu, 06 Apr 2017 23:49:10 -0400 In-Reply-To: <20170407030545.GA4296@dhcp-128-65.nay.redhat.com> References: <149142326734.5101.4596394505987813763.stgit@warthog.procyon.org.uk> <149142335441.5101.2294976563846442575.stgit@warthog.procyon.org.uk> <20170407030545.GA4296@dhcp-128-65.nay.redhat.com> 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-MML: disable x-cbid: 17040703-7323-0000-0000-000000E9FC85 X-IBM-AV-DETECTION: SAVI=unused REMOTE=unused XFE=unused x-cbparentid: 17040703-7324-0000-0000-0000028F2E81 Message-Id: <1491536950.4184.10.camel@linux.vnet.ibm.com> X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10432:,, definitions=2017-04-07_03:,, signatures=0 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 spamscore=0 suspectscore=2 malwarescore=0 phishscore=0 adultscore=0 bulkscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1702020001 definitions=main-1704070032 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1984 Lines: 61 On Fri, 2017-04-07 at 11:05 +0800, Dave Young wrote: > On 04/05/17 at 09:15pm, David Howells wrote: > > 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 > > cc: kexec@lists.infradead.org > > --- > > > > 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; > > + > > IMA can be used to verify file signatures too, based on the LSM hooks in  kernel_read_file_from_fd().  CONFIG_KEXEC_VERIFY_SIG should not be required. Mimi > /* Make sure we have a legal set of flags */ > > if (flags != (flags & KEXEC_FILE_FLAGS)) > > return -EINVAL; > > > > > > _______________________________________________ > > kexec mailing list > > kexec@lists.infradead.org > > http://lists.infradead.org/mailman/listinfo/kexec > > Acked-by: Dave Young > > Thanks > Dave > -- > 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 >