From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-7.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_PASS autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 6212CC07E85 for ; Thu, 29 Nov 2018 20:59:38 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 21FD720868 for ; Thu, 29 Nov 2018 20:59:38 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 21FD720868 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=linux.ibm.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-security-module-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726827AbeK3IGU (ORCPT ); Fri, 30 Nov 2018 03:06:20 -0500 Received: from mx0b-001b2d01.pphosted.com ([148.163.158.5]:59736 "EHLO mx0a-001b2d01.pphosted.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1726152AbeK3IGS (ORCPT ); Fri, 30 Nov 2018 03:06:18 -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 wATKwonM045736 for ; Thu, 29 Nov 2018 15:59:34 -0500 Received: from e06smtp07.uk.ibm.com (e06smtp07.uk.ibm.com [195.75.94.103]) by mx0b-001b2d01.pphosted.com with ESMTP id 2p2qcmrmxj-1 (version=TLSv1.2 cipher=AES256-GCM-SHA384 bits=256 verify=NOT) for ; Thu, 29 Nov 2018 15:59:34 -0500 Received: from localhost by e06smtp07.uk.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! 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Violators will be prosecuted; (version=TLSv1/SSLv3 cipher=AES256-GCM-SHA384 bits=256/256) Thu, 29 Nov 2018 20:59:26 -0000 Received: from b06wcsmtp001.portsmouth.uk.ibm.com (b06wcsmtp001.portsmouth.uk.ibm.com [9.149.105.160]) by b06cxnps4074.portsmouth.uk.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id wATKxPsF8520020 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=FAIL); Thu, 29 Nov 2018 20:59:25 GMT Received: from b06wcsmtp001.portsmouth.uk.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id D557FA405B; Thu, 29 Nov 2018 20:59:25 +0000 (GMT) Received: from b06wcsmtp001.portsmouth.uk.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id BA5B0A405F; Thu, 29 Nov 2018 20:59:23 +0000 (GMT) Received: from localhost.localdomain (unknown [9.80.103.235]) by b06wcsmtp001.portsmouth.uk.ibm.com (Postfix) with ESMTP; Thu, 29 Nov 2018 20:59:23 +0000 (GMT) Subject: Re: [PATCH v8 04/14] integrity: Introduce struct evm_xattr 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-doc@vger.kernel.org, linux-kernel@vger.kernel.org, Dmitry Kasatkin , James Morris , "Serge E. Hallyn" , David Howells , David Woodhouse , Jessica Yu , Herbert Xu , "David S. Miller" , Jonathan Corbet , "AKASHI, Takahiro" Date: Thu, 29 Nov 2018 15:59:12 -0500 In-Reply-To: <20181116200712.14154-5-bauerman@linux.ibm.com> References: <20181116200712.14154-1-bauerman@linux.ibm.com> <20181116200712.14154-5-bauerman@linux.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: 18112920-0028-0000-0000-000003238C40 X-IBM-AV-DETECTION: SAVI=unused REMOTE=unused XFE=unused x-cbparentid: 18112920-0029-0000-0000-000023DF9E7F Message-Id: <1543525152.3902.411.camel@linux.ibm.com> X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10434:,, definitions=2018-11-29_13:,, 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 mlxscore=0 impostorscore=0 mlxlogscore=999 adultscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1810050000 definitions=main-1811290175 Sender: owner-linux-security-module@vger.kernel.org Precedence: bulk List-ID: On Fri, 2018-11-16 at 18:07 -0200, Thiago Jung Bauermann wrote: > Even though struct evm_ima_xattr_data includes a fixed-size array to hold a > SHA1 digest, most of the code ignores the array and uses the struct to mean > "type indicator followed by data of unspecified size" and tracks the real > size of what the struct represents in a separate length variable. > > The only exception to that is the EVM code, which correctly uses the > definition of struct evm_ima_xattr_data. > > So make this explicit in the code by removing the length specification from > the array in struct evm_ima_xattr_data. Also, change the name of the > element from digest to data since in most places the array doesn't hold a > digest. > > A separate struct evm_xattr is introduced, with the original definition of > evm_ima_xattr_data to be used in the places that actually expect that > definition. , specifically the EVM HMAC code. > > Signed-off-by: Thiago Jung Bauermann Other than commenting the evm_xattr usage is limited to HMAC before the structure definition, this looks good. Reviewed-by: Mimi Zohar > --- > security/integrity/evm/evm_main.c | 8 ++++---- > security/integrity/ima/ima_appraise.c | 7 ++++--- > security/integrity/integrity.h | 5 +++++ > 3 files changed, 13 insertions(+), 7 deletions(-) > > diff --git a/security/integrity/evm/evm_main.c b/security/integrity/evm/evm_main.c > index 7f3f54d89a6e..a1b42d10efc7 100644 > --- a/security/integrity/evm/evm_main.c > +++ b/security/integrity/evm/evm_main.c > @@ -169,7 +169,7 @@ static enum integrity_status evm_verify_hmac(struct dentry *dentry, > /* check value type */ > switch (xattr_data->type) { > case EVM_XATTR_HMAC: > - if (xattr_len != sizeof(struct evm_ima_xattr_data)) { > + if (xattr_len != sizeof(struct evm_xattr)) { > evm_status = INTEGRITY_FAIL; > goto out; > } > @@ -179,7 +179,7 @@ static enum integrity_status evm_verify_hmac(struct dentry *dentry, > xattr_value_len, &digest); > if (rc) > break; > - rc = crypto_memneq(xattr_data->digest, digest.digest, > + rc = crypto_memneq(xattr_data->data, digest.digest, > SHA1_DIGEST_SIZE); > if (rc) > rc = -EINVAL; > @@ -523,7 +523,7 @@ int evm_inode_init_security(struct inode *inode, > const struct xattr *lsm_xattr, > struct xattr *evm_xattr) > { > - struct evm_ima_xattr_data *xattr_data; > + struct evm_xattr *xattr_data; > int rc; > > if (!evm_key_loaded() || !evm_protected_xattr(lsm_xattr->name)) > @@ -533,7 +533,7 @@ int evm_inode_init_security(struct inode *inode, > if (!xattr_data) > return -ENOMEM; > > - xattr_data->type = EVM_XATTR_HMAC; > + xattr_data->data.type = EVM_XATTR_HMAC; > rc = evm_init_hmac(inode, lsm_xattr, xattr_data->digest); > if (rc < 0) > goto out; > diff --git a/security/integrity/ima/ima_appraise.c b/security/integrity/ima/ima_appraise.c > index deec1804a00a..8bcef90939f8 100644 > --- a/security/integrity/ima/ima_appraise.c > +++ b/security/integrity/ima/ima_appraise.c > @@ -167,7 +167,8 @@ enum hash_algo ima_get_hash_algo(struct evm_ima_xattr_data *xattr_value, > return sig->hash_algo; > break; > case IMA_XATTR_DIGEST_NG: > - ret = xattr_value->digest[0]; > + /* first byte contains algorithm id */ > + ret = xattr_value->data[0]; > if (ret < HASH_ALGO__LAST) > return ret; > break; > @@ -175,7 +176,7 @@ enum hash_algo ima_get_hash_algo(struct evm_ima_xattr_data *xattr_value, > /* this is for backward compatibility */ > if (xattr_len == 21) { > unsigned int zero = 0; > - if (!memcmp(&xattr_value->digest[16], &zero, 4)) > + if (!memcmp(&xattr_value->data[16], &zero, 4)) > return HASH_ALGO_MD5; > else > return HASH_ALGO_SHA1; > @@ -274,7 +275,7 @@ int ima_appraise_measurement(enum ima_hooks func, > /* xattr length may be longer. md5 hash in previous > version occupied 20 bytes in xattr, instead of 16 > */ > - rc = memcmp(&xattr_value->digest[hash_start], > + rc = memcmp(&xattr_value->data[hash_start], > iint->ima_hash->digest, > iint->ima_hash->length); > else > diff --git a/security/integrity/integrity.h b/security/integrity/integrity.h > index e60473b13a8d..20ac02bf1b84 100644 > --- a/security/integrity/integrity.h > +++ b/security/integrity/integrity.h > @@ -79,6 +79,11 @@ enum evm_ima_xattr_type { > > struct evm_ima_xattr_data { > u8 type; > + u8 data[]; > +} __packed; > + Please add a comment here saying that evm_xattr is limited to HMAC. > +struct evm_xattr { > + struct evm_ima_xattr_data data; > u8 digest[SHA1_DIGEST_SIZE]; > } __packed; >