From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mx0a-001b2d01.pphosted.com (mx0a-001b2d01.pphosted.com [148.163.156.1]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by lists.ozlabs.org (Postfix) with ESMTPS id 402y4b0TcczF1ZR for ; Sat, 17 Mar 2018 07:39:42 +1100 (AEDT) Received: from pps.filterd (m0098394.ppops.net [127.0.0.1]) by mx0a-001b2d01.pphosted.com (8.16.0.22/8.16.0.22) with SMTP id w2GKdWrO010122 for ; Fri, 16 Mar 2018 16:39:40 -0400 Received: from e33.co.us.ibm.com (e33.co.us.ibm.com [32.97.110.151]) by mx0a-001b2d01.pphosted.com with ESMTP id 2grhudqees-1 (version=TLSv1.2 cipher=AES256-SHA256 bits=256 verify=NOT) for ; Fri, 16 Mar 2018 16:39:40 -0400 Received: from localhost by e33.co.us.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted for from ; Fri, 16 Mar 2018 14:39:39 -0600 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 v6 03/12] PKCS#7: Introduce pkcs7_get_digest() Date: Fri, 16 Mar 2018 17:38:28 -0300 In-Reply-To: <20180316203837.10174-1-bauerman@linux.vnet.ibm.com> References: <20180316203837.10174-1-bauerman@linux.vnet.ibm.com> Message-Id: <20180316203837.10174-4-bauerman@linux.vnet.ibm.com> List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , 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 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 39e6de0c2761..bd02360f8be5 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 */