From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753729AbeEWA0W (ORCPT ); Tue, 22 May 2018 20:26:22 -0400 Received: from mx0b-001b2d01.pphosted.com ([148.163.158.5]:54748 "EHLO mx0a-001b2d01.pphosted.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1753714AbeEWA0S (ORCPT ); Tue, 22 May 2018 20:26:18 -0400 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-kernel@vger.kernel.org, Mimi Zohar , Dmitry Kasatkin , James Morris , "Serge E. Hallyn" , David Howells , David Woodhouse , Jessica Yu , Herbert Xu , "David S. Miller" , "AKASHI, Takahiro" , Thiago Jung Bauermann Subject: [PATCH v7 06/14] integrity: Introduce asymmetric_sig_has_known_key() Date: Tue, 22 May 2018 21:12:45 -0300 X-Mailer: git-send-email 2.16.2 In-Reply-To: <20180523001253.15247-1-bauerman@linux.ibm.com> References: <20180523001253.15247-1-bauerman@linux.ibm.com> X-TM-AS-GCONF: 00 x-cbid: 18052300-0028-0000-0000-000009AB734E X-IBM-SpamModules-Scores: X-IBM-SpamModules-Versions: BY=3.00009068; HX=3.00000241; KW=3.00000007; PH=3.00000004; SC=3.00000261; SDB=6.01036241; UDB=6.00530093; IPR=6.00815369; MB=3.00021248; MTD=3.00000008; XFM=3.00000015; UTC=2018-05-23 00:26:15 X-IBM-AV-DETECTION: SAVI=unused REMOTE=unused XFE=unused x-cbparentid: 18052300-0029-0000-0000-00003AF3AEE5 Message-Id: <20180523001253.15247-7-bauerman@linux.ibm.com> X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10434:,, definitions=2018-05-22_09:,, 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 impostorscore=0 adultscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1709140000 definitions=main-1805230002 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 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 ab6a029062a1..241647970c19 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); @@ -109,7 +131,7 @@ 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 d4f676906442..7f80c3e44d51 100644 --- a/security/integrity/integrity.h +++ b/security/integrity/integrity.h @@ -181,12 +181,20 @@ static inline int integrity_init_keyring(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