From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751858AbeCVXIM (ORCPT ); Thu, 22 Mar 2018 19:08:12 -0400 Received: from mx0a-001b2d01.pphosted.com ([148.163.156.1]:54600 "EHLO mx0a-001b2d01.pphosted.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751734AbeCVXIJ (ORCPT ); Thu, 22 Mar 2018 19:08:09 -0400 Subject: Re: [PATCH v6 03/12] PKCS#7: Introduce pkcs7_get_digest() From: Mimi Zohar To: Thiago Jung Bauermann , 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, Dmitry Kasatkin , James Morris , "Serge E. Hallyn" , David Howells , David Woodhouse , Jessica Yu , Herbert Xu , "David S. Miller" , "AKASHI, Takahiro" Date: Thu, 22 Mar 2018 19:07:58 -0400 In-Reply-To: <20180316203837.10174-4-bauerman@linux.vnet.ibm.com> References: <20180316203837.10174-1-bauerman@linux.vnet.ibm.com> <20180316203837.10174-4-bauerman@linux.vnet.ibm.com> Content-Type: text/plain; charset="UTF-8" X-Mailer: Evolution 3.20.5 (3.20.5-1.fc24) Mime-Version: 1.0 Content-Transfer-Encoding: 7bit X-TM-AS-GCONF: 00 x-cbid: 18032223-0040-0000-0000-000004445D51 X-IBM-AV-DETECTION: SAVI=unused REMOTE=unused XFE=unused x-cbparentid: 18032223-0041-0000-0000-000020E787EA Message-Id: <1521760078.3848.301.camel@linux.vnet.ibm.com> X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10432:,, definitions=2018-03-22_11:,, signatures=0 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 priorityscore=1501 malwarescore=0 suspectscore=0 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-1803220258 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, 2018-03-16 at 17:38 -0300, Thiago Jung Bauermann wrote: > 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" Reviewed-by: Mimi Zohar > --- > 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 */ >