Return-Path: Received: from mx0b-001b2d01.pphosted.com ([148.163.158.5]:53532 "EHLO mx0a-001b2d01.pphosted.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1727593AbeKQGWV (ORCPT ); Sat, 17 Nov 2018 01:22:21 -0500 Received: from pps.filterd (m0098416.ppops.net [127.0.0.1]) by mx0b-001b2d01.pphosted.com (8.16.0.22/8.16.0.22) with SMTP id wAGK4FmG089951 for ; Fri, 16 Nov 2018 15:08:32 -0500 Received: from e17.ny.us.ibm.com (e17.ny.us.ibm.com [129.33.205.207]) by mx0b-001b2d01.pphosted.com with ESMTP id 2nt11897u0-1 (version=TLSv1.2 cipher=AES256-GCM-SHA384 bits=256 verify=NOT) for ; Fri, 16 Nov 2018 15:08:31 -0500 Received: from localhost by e17.ny.us.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted for from ; Fri, 16 Nov 2018 20:08:31 -0000 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 v8 03/14] PKCS#7: Introduce pkcs7_get_digest() Date: Fri, 16 Nov 2018 18:07:01 -0200 In-Reply-To: <20181116200712.14154-1-bauerman@linux.ibm.com> References: <20181116200712.14154-1-bauerman@linux.ibm.com> Message-Id: <20181116200712.14154-4-bauerman@linux.ibm.com> Sender: linux-crypto-owner@vger.kernel.org List-ID: 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 */