From patchwork Thu Dec 13 02:08:59 2018 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Thiago Jung Bauermann X-Patchwork-Id: 10727559 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 6C55B13AF for ; Thu, 13 Dec 2018 02:11:37 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 5D60F2B9D8 for ; Thu, 13 Dec 2018 02:11:37 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 512EE2BA33; Thu, 13 Dec 2018 02:11:37 +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=-7.9 required=2.0 tests=BAYES_00,MAILING_LIST_MULTI, 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 DF70B2BA2B for ; Thu, 13 Dec 2018 02:11:36 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726748AbeLMCLa (ORCPT ); Wed, 12 Dec 2018 21:11:30 -0500 Received: from mx0a-001b2d01.pphosted.com ([148.163.156.1]:40166 "EHLO mx0a-001b2d01.pphosted.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726842AbeLMCL3 (ORCPT ); Wed, 12 Dec 2018 21:11:29 -0500 Received: from pps.filterd (m0098399.ppops.net [127.0.0.1]) by mx0a-001b2d01.pphosted.com (8.16.0.22/8.16.0.22) with SMTP id wBD23h71063886 for ; Wed, 12 Dec 2018 21:11:28 -0500 Received: from e34.co.us.ibm.com (e34.co.us.ibm.com [32.97.110.152]) by mx0a-001b2d01.pphosted.com with ESMTP id 2pbasqsdj4-1 (version=TLSv1.2 cipher=AES256-GCM-SHA384 bits=256 verify=NOT) for ; Wed, 12 Dec 2018 21:11:28 -0500 Received: from localhost by e34.co.us.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) Thu, 13 Dec 2018 02:11:22 -0000 Received: from b03ledav006.gho.boulder.ibm.com (b03ledav006.gho.boulder.ibm.com [9.17.130.237]) by b03cxnp08027.gho.boulder.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id wBD2BLbg20316180 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=FAIL); Thu, 13 Dec 2018 02:11:21 GMT Received: from b03ledav006.gho.boulder.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 46469C6067; Thu, 13 Dec 2018 02:11:21 +0000 (GMT) Received: from b03ledav006.gho.boulder.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 31EBFC6055; Thu, 13 Dec 2018 02:11:17 +0000 (GMT) Received: from morokweng.localdomain.com (unknown [9.80.227.60]) by b03ledav006.gho.boulder.ibm.com (Postfix) with ESMTP; Thu, 13 Dec 2018 02:11:16 +0000 (GMT) From: Thiago Jung Bauermann To: linux-integrity@vger.kernel.org Cc: linux-security-module@vger.kernel.org, keyrings@vger.kernel.org, linux-crypto@vger.kernel.org, linuxppc-dev@lists.ozlabs.org, linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org, Mimi Zohar , Dmitry Kasatkin , James Morris , "Serge E. Hallyn" , David Howells , David Woodhouse , Jessica Yu , Herbert Xu , "David S. Miller" , Jonathan Corbet , "AKASHI, Takahiro" , Thiago Jung Bauermann Subject: [PATCH v9 06/14] integrity: Introduce asymmetric_sig_has_known_key() Date: Thu, 13 Dec 2018 00:08:59 -0200 X-Mailer: git-send-email 2.17.2 In-Reply-To: <20181213020907.13601-1-bauerman@linux.ibm.com> References: <20181213020907.13601-1-bauerman@linux.ibm.com> X-TM-AS-GCONF: 00 x-cbid: 18121302-0016-0000-0000-00000963A3F0 X-IBM-SpamModules-Scores: X-IBM-SpamModules-Versions: BY=3.00010217; HX=3.00000242; KW=3.00000007; PH=3.00000004; SC=3.00000270; SDB=6.01130951; UDB=6.00587714; IPR=6.00911085; MB=3.00024674; MTD=3.00000008; XFM=3.00000015; UTC=2018-12-13 02:11:27 X-IBM-AV-DETECTION: SAVI=unused REMOTE=unused XFE=unused x-cbparentid: 18121302-0017-0000-0000-00004162A097 Message-Id: <20181213020907.13601-7-bauerman@linux.ibm.com> X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10434:,, definitions=2018-12-12_04:,, 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=999 adultscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1810050000 definitions=main-1812130017 Sender: linux-integrity-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-integrity@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP IMA will only look for a modsig if the xattr sig references a key which is not in the expected kernel keyring. To that end, introduce asymmetric_sig_has_known_key(). The logic of extracting the key used in the xattr sig is factored out from asymmetric_verify() so that it can be used by the new function. Signed-off-by: Thiago Jung Bauermann Signed-off-by: Mimi Zohar --- security/integrity/digsig_asymmetric.c | 44 +++++++++++++++++++------- security/integrity/integrity.h | 8 +++++ 2 files changed, 41 insertions(+), 11 deletions(-) diff --git a/security/integrity/digsig_asymmetric.c b/security/integrity/digsig_asymmetric.c index d775e03fbbcc..4c3c49f919f5 100644 --- a/security/integrity/digsig_asymmetric.c +++ b/security/integrity/digsig_asymmetric.c @@ -79,26 +79,48 @@ static struct key *request_asymmetric_key(struct key *keyring, uint32_t keyid) return key; } -int asymmetric_verify(struct key *keyring, const char *sig, - int siglen, const char *data, int datalen) +static struct key *asymmetric_key_from_sig(struct key *keyring, const char *sig, + int siglen) { - struct public_key_signature pks; - struct signature_v2_hdr *hdr = (struct signature_v2_hdr *)sig; - struct key *key; - int ret = -ENOMEM; + const struct signature_v2_hdr *hdr = (struct signature_v2_hdr *) sig; if (siglen <= sizeof(*hdr)) - return -EBADMSG; + return ERR_PTR(-EBADMSG); siglen -= sizeof(*hdr); if (siglen != be16_to_cpu(hdr->sig_size)) - return -EBADMSG; + return ERR_PTR(-EBADMSG); if (hdr->hash_algo >= HASH_ALGO__LAST) - return -ENOPKG; + return ERR_PTR(-ENOPKG); + + return request_asymmetric_key(keyring, be32_to_cpu(hdr->keyid)); +} + +bool asymmetric_sig_has_known_key(struct key *keyring, const char *sig, + int siglen) +{ + struct key *key; + + key = asymmetric_key_from_sig(keyring, sig, siglen); + if (IS_ERR_OR_NULL(key)) + return false; + + key_put(key); + + return true; +} + +int asymmetric_verify(struct key *keyring, const char *sig, + int siglen, const char *data, int datalen) +{ + struct public_key_signature pks; + struct signature_v2_hdr *hdr = (struct signature_v2_hdr *)sig; + struct key *key; + int ret = -ENOMEM; - key = request_asymmetric_key(keyring, be32_to_cpu(hdr->keyid)); + key = asymmetric_key_from_sig(keyring, sig, siglen); if (IS_ERR(key)) return PTR_ERR(key); @@ -110,7 +132,7 @@ int asymmetric_verify(struct key *keyring, const char *sig, pks.digest = (u8 *)data; pks.digest_size = datalen; pks.s = hdr->sig; - pks.s_size = siglen; + pks.s_size = siglen - sizeof(*hdr); ret = verify_signature(key, &pks); key_put(key); pr_debug("%s() = %d\n", __func__, ret); diff --git a/security/integrity/integrity.h b/security/integrity/integrity.h index 6f657260a964..dec5ab8cf9e9 100644 --- a/security/integrity/integrity.h +++ b/security/integrity/integrity.h @@ -194,12 +194,20 @@ static inline int __init integrity_load_cert(const unsigned int id, #ifdef CONFIG_INTEGRITY_ASYMMETRIC_KEYS int asymmetric_verify(struct key *keyring, const char *sig, int siglen, const char *data, int datalen); +bool asymmetric_sig_has_known_key(struct key *keyring, const char *sig, + int siglen); #else static inline int asymmetric_verify(struct key *keyring, const char *sig, int siglen, const char *data, int datalen) { return -EOPNOTSUPP; } + +static inline bool asymmetric_sig_has_known_key(struct key *keyring, + const char *sig, int siglen) +{ + return false; +} #endif #ifdef CONFIG_IMA_LOAD_X509