From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753667AbeEWA0D (ORCPT ); Tue, 22 May 2018 20:26:03 -0400 Received: from mx0b-001b2d01.pphosted.com ([148.163.158.5]:35934 "EHLO mx0a-001b2d01.pphosted.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1753644AbeEWAZ4 (ORCPT ); Tue, 22 May 2018 20:25:56 -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 03/14] PKCS#7: Introduce pkcs7_get_digest() Date: Tue, 22 May 2018 21:12:42 -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: 18052300-0024-0000-0000-0000187696C7 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 00:25:53 X-IBM-AV-DETECTION: SAVI=unused REMOTE=unused XFE=unused x-cbparentid: 18052300-0025-0000-0000-0000501C2EFE Message-Id: <20180523001253.15247-4-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 need to access the digest of the PKCS7 message (as calculated by the kernel) before the signature is verified, so introduce pkcs7_get_digest() for that purpose. Also, modify pkcs7_digest() to detect when the digest was already calculated so that it doesn't have to do redundant work. Verifying that sinfo->sig->digest isn't NULL is sufficient because both places which allocate sinfo->sig (pkcs7_parse_message() and pkcs7_note_signed_info()) use kzalloc() so sig->digest is always initialized to zero. Signed-off-by: Thiago Jung Bauermann Reviewed-by: Mimi Zohar Cc: David Howells Cc: Herbert Xu Cc: "David S. Miller" --- crypto/asymmetric_keys/pkcs7_verify.c | 25 +++++++++++++++++++++++++ include/crypto/pkcs7.h | 3 +++ 2 files changed, 28 insertions(+) diff --git a/crypto/asymmetric_keys/pkcs7_verify.c b/crypto/asymmetric_keys/pkcs7_verify.c index 97c77f66b20d..e61f121bfc87 100644 --- a/crypto/asymmetric_keys/pkcs7_verify.c +++ b/crypto/asymmetric_keys/pkcs7_verify.c @@ -33,6 +33,10 @@ static int pkcs7_digest(struct pkcs7_message *pkcs7, kenter(",%u,%s", sinfo->index, sinfo->sig->hash_algo); + /* The digest was calculated already. */ + if (sig->digest) + return 0; + if (!sinfo->sig->hash_algo) return -ENOPKG; @@ -122,6 +126,27 @@ static int pkcs7_digest(struct pkcs7_message *pkcs7, return ret; } +int pkcs7_get_digest(struct pkcs7_message *pkcs7, const u8 **buf, u8 *len) +{ + struct pkcs7_signed_info *sinfo = pkcs7->signed_infos; + int ret; + + /* + * This function doesn't support messages with more than one signature. + */ + if (sinfo == NULL || sinfo->next != NULL) + return -EBADMSG; + + ret = pkcs7_digest(pkcs7, sinfo); + if (ret) + return ret; + + *buf = sinfo->sig->digest; + *len = sinfo->sig->digest_size; + + return 0; +} + /* * Find the key (X.509 certificate) to use to verify a PKCS#7 message. PKCS#7 * uses the issuer's name and the issuing certificate serial number for diff --git a/include/crypto/pkcs7.h b/include/crypto/pkcs7.h index 6f51d0cb6d12..cfaea9c37f4a 100644 --- a/include/crypto/pkcs7.h +++ b/include/crypto/pkcs7.h @@ -46,4 +46,7 @@ extern int pkcs7_verify(struct pkcs7_message *pkcs7, extern int pkcs7_supply_detached_data(struct pkcs7_message *pkcs7, const void *data, size_t datalen); +extern int pkcs7_get_digest(struct pkcs7_message *pkcs7, const u8 **buf, + u8 *len); + #endif /* _CRYPTO_PKCS7_H */