From patchwork Wed Sep 26 12:22:06 2018 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Nayna X-Patchwork-Id: 10615883 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 9DA613CF1 for ; Wed, 26 Sep 2018 12:25:54 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 914B02A6F6 for ; Wed, 26 Sep 2018 12:25:54 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 7E99F2AC2B; Wed, 26 Sep 2018 12:25:54 +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 274CA2A6F6 for ; Wed, 26 Sep 2018 12:25:54 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726802AbeIZSih (ORCPT ); Wed, 26 Sep 2018 14:38:37 -0400 Received: from mx0a-001b2d01.pphosted.com ([148.163.156.1]:59286 "EHLO mx0a-001b2d01.pphosted.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727672AbeIZSiH (ORCPT ); Wed, 26 Sep 2018 14:38:07 -0400 Received: from pps.filterd (m0098404.ppops.net [127.0.0.1]) by mx0a-001b2d01.pphosted.com (8.16.0.22/8.16.0.22) with SMTP id w8QCOgIE113310 for ; Wed, 26 Sep 2018 08:25:21 -0400 Received: from e06smtp01.uk.ibm.com (e06smtp01.uk.ibm.com [195.75.94.97]) by mx0a-001b2d01.pphosted.com with ESMTP id 2mr9huhtfu-1 (version=TLSv1.2 cipher=AES256-GCM-SHA384 bits=256 verify=NOT) for ; Wed, 26 Sep 2018 08:25:21 -0400 Received: from localhost by e06smtp01.uk.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! 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Violators will be prosecuted; (version=TLSv1/SSLv3 cipher=AES256-GCM-SHA384 bits=256/256) Wed, 26 Sep 2018 13:25:16 +0100 Received: from d06av21.portsmouth.uk.ibm.com (d06av21.portsmouth.uk.ibm.com [9.149.105.232]) by b06cxnps3075.portsmouth.uk.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id w8QCPFFs63307904 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=FAIL); Wed, 26 Sep 2018 12:25:15 GMT Received: from d06av21.portsmouth.uk.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id AF80E52067; Wed, 26 Sep 2018 15:24:56 +0100 (BST) Received: from swastik.in.ibm.com (unknown [9.124.31.41]) by d06av21.portsmouth.uk.ibm.com (Postfix) with ESMTP id 4794952052; Wed, 26 Sep 2018 15:24:55 +0100 (BST) From: Nayna Jain To: linux-integrity@vger.kernel.org Cc: zohar@linux.ibm.com, linux-security-module@vger.kernel.org, linux-efi@vger.kernel.org, linux-kernel@vger.kernel.org, dhowells@redhat.com, jforbes@redhat.com, Nayna Jain Subject: [PATCH v4 2/6] ima: prevent kexec_load syscall based on runtime secureboot flag Date: Wed, 26 Sep 2018 17:52:06 +0530 X-Mailer: git-send-email 2.13.6 In-Reply-To: <20180926122210.14642-1-nayna@linux.vnet.ibm.com> References: <20180926122210.14642-1-nayna@linux.vnet.ibm.com> X-TM-AS-GCONF: 00 x-cbid: 18092612-4275-0000-0000-000002C0C747 X-IBM-AV-DETECTION: SAVI=unused REMOTE=unused XFE=unused x-cbparentid: 18092612-4276-0000-0000-000037CACE24 Message-Id: <20180926122210.14642-3-nayna@linux.vnet.ibm.com> X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10434:,, definitions=2018-09-26_06:,, signatures=0 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 priorityscore=1501 malwarescore=0 suspectscore=1 phishscore=0 bulkscore=0 spamscore=0 clxscore=1015 lowpriorityscore=0 mlxscore=0 impostorscore=0 mlxlogscore=923 adultscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1807170000 definitions=main-1809260123 Sender: owner-linux-security-module@vger.kernel.org Precedence: bulk List-ID: X-Virus-Scanned: ClamAV using ClamSMTP When CONFIG_KEXEC_VERIFY_SIG is enabled, the kexec_file_load syscall requires the kexec'd kernel image to be signed. Distros are concerned about totally disabling the kexec_load syscall. As a compromise, the kexec_load syscall will only be disabled when CONFIG_KEXEC_VERIFY_SIG is configured and the system is booted with secureboot enabled. This patch disables the kexec_load syscall only for systems booted with secureboot enabled. Signed-off-by: Nayna Jain --- security/integrity/ima/ima_main.c | 17 +++++++++++------ 1 file changed, 11 insertions(+), 6 deletions(-) diff --git a/security/integrity/ima/ima_main.c b/security/integrity/ima/ima_main.c index dce0a8a217bb..bdb6e5563d05 100644 --- a/security/integrity/ima/ima_main.c +++ b/security/integrity/ima/ima_main.c @@ -505,20 +505,24 @@ int ima_post_read_file(struct file *file, void *buf, loff_t size, */ int ima_load_data(enum kernel_load_data_id id) { - bool sig_enforce; + bool ima_enforce, sig_enforce; - if ((ima_appraise & IMA_APPRAISE_ENFORCE) != IMA_APPRAISE_ENFORCE) - return 0; + ima_enforce = + (ima_appraise & IMA_APPRAISE_ENFORCE) == IMA_APPRAISE_ENFORCE; switch (id) { case LOADING_KEXEC_IMAGE: - if (ima_appraise & IMA_APPRAISE_KEXEC) { +#ifdef CONFIG_KEXEC_VERIFY_SIG + if (arch_ima_get_secureboot()) + return -EACCES; +#endif + if (ima_enforce && (ima_appraise & IMA_APPRAISE_KEXEC)) { pr_err("impossible to appraise a kernel image without a file descriptor; try using kexec_file_load syscall.\n"); return -EACCES; /* INTEGRITY_UNKNOWN */ } break; case LOADING_FIRMWARE: - if (ima_appraise & IMA_APPRAISE_FIRMWARE) { + if (ima_enforce && (ima_appraise & IMA_APPRAISE_FIRMWARE)) { pr_err("Prevent firmware sysfs fallback loading.\n"); return -EACCES; /* INTEGRITY_UNKNOWN */ } @@ -526,7 +530,8 @@ int ima_load_data(enum kernel_load_data_id id) case LOADING_MODULE: sig_enforce = is_module_sig_enforced(); - if (!sig_enforce && (ima_appraise & IMA_APPRAISE_MODULES)) { + if (ima_enforce && (!sig_enforce + && (ima_appraise & IMA_APPRAISE_MODULES))) { pr_err("impossible to appraise a module without a file descriptor. sig_enforce kernel parameter might help\n"); return -EACCES; /* INTEGRITY_UNKNOWN */ }