From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-8.2 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, USER_AGENT_SANE_2 autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id E31F9C432C3 for ; Wed, 13 Nov 2019 20:09:34 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 7E24A20679 for ; Wed, 13 Nov 2019 20:09:35 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726980AbfKMUJd (ORCPT ); Wed, 13 Nov 2019 15:09:33 -0500 Received: from mx0a-001b2d01.pphosted.com ([148.163.156.1]:55732 "EHLO mx0a-001b2d01.pphosted.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726179AbfKMUJd (ORCPT ); Wed, 13 Nov 2019 15:09:33 -0500 Received: from pps.filterd (m0098393.ppops.net [127.0.0.1]) by mx0a-001b2d01.pphosted.com (8.16.0.27/8.16.0.27) with SMTP id xADK7fid091812 for ; Wed, 13 Nov 2019 15:09:32 -0500 Received: from e06smtp01.uk.ibm.com (e06smtp01.uk.ibm.com [195.75.94.97]) by mx0a-001b2d01.pphosted.com with ESMTP id 2w8n79qvw0-1 (version=TLSv1.2 cipher=AES256-GCM-SHA384 bits=256 verify=NOT) for ; Wed, 13 Nov 2019 15:09:31 -0500 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, 13 Nov 2019 20:09:24 -0000 Received: from d06av22.portsmouth.uk.ibm.com (d06av22.portsmouth.uk.ibm.com [9.149.105.58]) by b06cxnps4076.portsmouth.uk.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id xADK9Nom41943190 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Wed, 13 Nov 2019 20:09:23 GMT Received: from d06av22.portsmouth.uk.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 0B7B04C04E; Wed, 13 Nov 2019 20:09:23 +0000 (GMT) Received: from d06av22.portsmouth.uk.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 12CE84C044; Wed, 13 Nov 2019 20:09:22 +0000 (GMT) Received: from dhcp-9-31-103-201.watson.ibm.com (unknown [9.31.103.201]) by d06av22.portsmouth.uk.ibm.com (Postfix) with ESMTP; Wed, 13 Nov 2019 20:09:21 +0000 (GMT) Subject: Re: [PATCH v6 2/3] IMA: Define an IMA hook to measure keys From: Mimi Zohar To: Lakshmi Ramasubramanian , dhowells@redhat.com, matthewgarrett@google.com, sashal@kernel.org, jamorris@linux.microsoft.com, linux-integrity@vger.kernel.org, linux-security-module@vger.kernel.org, keyrings@vger.kernel.org, linux-kernel@vger.kernel.org Date: Wed, 13 Nov 2019 15:09:21 -0500 In-Reply-To: <20191113184658.2862-3-nramas@linux.microsoft.com> References: <20191113184658.2862-1-nramas@linux.microsoft.com> <20191113184658.2862-3-nramas@linux.microsoft.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-GCONF: 00 x-cbid: 19111320-4275-0000-0000-0000037D7AD4 X-IBM-AV-DETECTION: SAVI=unused REMOTE=unused XFE=unused x-cbparentid: 19111320-4276-0000-0000-00003890DDFA Message-Id: <1573675761.4843.13.camel@linux.ibm.com> X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10434:,, definitions=2019-11-13_04:,, signatures=0 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 priorityscore=1501 malwarescore=0 suspectscore=4 phishscore=0 bulkscore=0 spamscore=0 clxscore=1015 lowpriorityscore=0 mlxscore=0 impostorscore=0 mlxlogscore=999 adultscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1910280000 definitions=main-1911130164 Sender: owner-linux-security-module@vger.kernel.org Precedence: bulk List-ID: On Wed, 2019-11-13 at 10:46 -0800, Lakshmi Ramasubramanian wrote: > Measure asymmetric keys used for verifying file signatures, > certificates, etc. > > This patch defines a new IMA hook namely ima_post_key_create_or_update() > to measure asymmetric keys. > > Note that currently IMA subsystem can be enabled without > enabling KEYS subsystem. > > Adding support for measuring asymmetric keys in IMA requires KEYS > subsystem to be enabled. To handle this dependency a new config > namely CONFIG_IMA_MEASURE_ASYMMETRIC_KEYS has been added. Enabling > this config requires the following configs to be enabled: > CONFIG_IMA, CONFIG_KEYS, CONFIG_ASYMMETRIC_KEY_TYPE, and > CONFIG_ASYMMETRIC_PUBLIC_KEY_SUBTYPE. > > CONFIG_IMA_MEASURE_ASYMMETRIC_KEYS is off by default. > > The IMA hook is defined in a new file namely ima_asymmetric_keys.c > which is built only if CONFIG_IMA_MEASURE_ASYMMETRIC_KEYS is enabled. > > Signed-off-by: Lakshmi Ramasubramanian All that is is needed is the key and public_key structures, which are defined in include/linux/keys.h and include/crypto/public_key.h.  If the keys subsystem is disabled, then the new IMA hook won't be called.  There's no need for a new Kconfig option or a new file. Please move the hook to just after ima_kexec_cmdline(). Mimi > --- > security/integrity/ima/Kconfig | 14 ++++++ > security/integrity/ima/Makefile | 1 + > security/integrity/ima/ima_asymmetric_keys.c | 51 ++++++++++++++++++++ > 3 files changed, 66 insertions(+) > create mode 100644 security/integrity/ima/ima_asymmetric_keys.c > > diff --git a/security/integrity/ima/Kconfig b/security/integrity/ima/Kconfig > index 838476d780e5..c6d14884bc19 100644 > --- a/security/integrity/ima/Kconfig > +++ b/security/integrity/ima/Kconfig > @@ -310,3 +310,17 @@ config IMA_APPRAISE_SIGNED_INIT > default n > help > This option requires user-space init to be signed. > + > +config IMA_MEASURE_ASYMMETRIC_KEYS > + bool "Enable measuring asymmetric keys on key create or update" > + depends on IMA > + depends on KEYS > + depends on ASYMMETRIC_KEY_TYPE > + depends on ASYMMETRIC_PUBLIC_KEY_SUBTYPE > + default n > + help > + This option enables measuring asymmetric keys when > + the key is created or updated. Additionally, IMA policy > + needs to be configured to either measure keys linked to > + any keyring or only measure keys linked to the keyrings > + specified in the IMA policy through the keyrings= option. > diff --git a/security/integrity/ima/Makefile b/security/integrity/ima/Makefile > index 31d57cdf2421..3e9d0ad68c7b 100644 > --- a/security/integrity/ima/Makefile > +++ b/security/integrity/ima/Makefile > @@ -12,3 +12,4 @@ ima-$(CONFIG_IMA_APPRAISE) += ima_appraise.o > ima-$(CONFIG_IMA_APPRAISE_MODSIG) += ima_modsig.o > ima-$(CONFIG_HAVE_IMA_KEXEC) += ima_kexec.o > obj-$(CONFIG_IMA_BLACKLIST_KEYRING) += ima_mok.o > +obj-$(CONFIG_IMA_MEASURE_ASYMMETRIC_KEYS) += ima_asymmetric_keys.o > diff --git a/security/integrity/ima/ima_asymmetric_keys.c b/security/integrity/ima/ima_asymmetric_keys.c > new file mode 100644 > index 000000000000..f6884641a622 > --- /dev/null > +++ b/security/integrity/ima/ima_asymmetric_keys.c > @@ -0,0 +1,51 @@ > +// SPDX-License-Identifier: GPL-2.0+ > +/* > + * Copyright (C) 2019 Microsoft Corporation > + * > + * Author: Lakshmi Ramasubramanian (nramas@linux.microsoft.com) > + * > + * File: ima_asymmetric_keys.c > + * Defines an IMA hook to measure asymmetric keys on key > + * create or update. > + */ > + > +#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt > + > +#include > +#include > +#include "ima.h" > + > +/** > + * ima_post_key_create_or_update - measure asymmetric keys > + * @keyring: keyring to which the key is linked to > + * @key: created or updated key > + * @flags: key flags > + * @create: flag indicating whether the key was created or updated > + * > + * Keys can only be measured, not appraised. > + */ > +void ima_post_key_create_or_update(struct key *keyring, struct key *key, > + unsigned long flags, bool create) > +{ > + const struct public_key *pk; > + > + /* Only asymmetric keys are handled by this hook. */ > + if (key->type != &key_type_asymmetric) > + return; > + > + /* Get the public_key of the given asymmetric key to measure. */ > + pk = key->payload.data[asym_crypto]; > + > + /* > + * keyring->description points to the name of the keyring > + * (such as ".builtin_trusted_keys", ".ima", etc.) to > + * which the given key is linked to. > + * > + * The name of the keyring is passed in the "eventname" > + * parameter to process_buffer_measurement() and is set > + * in the "eventname" field in ima_event_data for > + * the key measurement IMA event. > + */ > + process_buffer_measurement(pk->key, pk->keylen, > + keyring->description, KEY_CHECK, 0); > +}