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Violators will be prosecuted; (version=TLSv1/SSLv3 cipher=AES256-GCM-SHA384 bits=256/256) Thu, 29 Aug 2019 04:45:57 +0100 Received: from d06av24.portsmouth.uk.ibm.com (mk.ibm.com [9.149.105.60]) by b06cxnps4076.portsmouth.uk.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id x7T3juQf51839122 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Thu, 29 Aug 2019 03:45:56 GMT Received: from d06av24.portsmouth.uk.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id BED444204C; Thu, 29 Aug 2019 03:45:56 +0000 (GMT) Received: from d06av24.portsmouth.uk.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id A0A8342041; Thu, 29 Aug 2019 03:45:55 +0000 (GMT) Received: from localhost.localdomain (unknown [9.85.163.216]) by d06av24.portsmouth.uk.ibm.com (Postfix) with ESMTP; Thu, 29 Aug 2019 03:45:55 +0000 (GMT) Subject: Re: [PATCH] ima: use struct_size() in kzalloc() From: Mimi Zohar To: "Gustavo A. R. Silva" , Dmitry Kasatkin , James Morris , "Serge E. Hallyn" Cc: linux-integrity@vger.kernel.org, linux-security-module@vger.kernel.org, linux-kernel@vger.kernel.org Date: Wed, 28 Aug 2019 23:45:55 -0400 In-Reply-To: <671185b9-5c91-5235-b5ea-96d3449bf716@embeddedor.com> References: <20190529165343.GA2584@embeddedor> <671185b9-5c91-5235-b5ea-96d3449bf716@embeddedor.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: 8bit X-TM-AS-GCONF: 00 x-cbid: 19082903-4275-0000-0000-0000035E859E X-IBM-AV-DETECTION: SAVI=unused REMOTE=unused XFE=unused x-cbparentid: 19082903-4276-0000-0000-00003870BB55 Message-Id: <1567050355.11493.3.camel@linux.ibm.com> X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10434:,, definitions=2019-08-29_03:,, 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=989 adultscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1906280000 definitions=main-1908290038 Sender: linux-integrity-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-integrity@vger.kernel.org Hi Gustavo, On Wed, 2019-08-28 at 13:29 -0500, Gustavo A. R. Silva wrote: > On 5/29/19 11:53 AM, Gustavo A. R. Silva wrote: > > One of the more common cases of allocation size calculations is finding > > the size of a structure that has a zero-sized array at the end, along > > with memory for some number of elements for that array. For example: > > > > struct foo { > > int stuff; > > struct boo entry[]; > > }; > > > > instance = kzalloc(sizeof(struct foo) + count * sizeof(struct boo), GFP_KERNEL); > > > > Instead of leaving these open-coded and prone to type mistakes, we can > > now use the new struct_size() helper: > > > > instance = kzalloc(struct_size(instance, entry, count), GFP_KERNEL); > > > > This code was detected with the help of Coccinelle. > > > > Signed-off-by: Gustavo A. R. Silva > > --- > > security/integrity/ima/ima_template.c | 5 ++--- > > 1 file changed, 2 insertions(+), 3 deletions(-) > > > > diff --git a/security/integrity/ima/ima_template.c b/security/integrity/ima/ima_template.c > > index b631b8bc7624..b945dff2ed14 100644 > > --- a/security/integrity/ima/ima_template.c > > +++ b/security/integrity/ima/ima_template.c > > @@ -281,9 +281,8 @@ static int ima_restore_template_data(struct ima_template_desc *template_desc, > > int ret = 0; > > int i; > > > > - *entry = kzalloc(sizeof(**entry) + > > - template_desc->num_fields * sizeof(struct ima_field_data), > > - GFP_NOFS); > > + *entry = kzalloc(struct_size(*entry, template_data, > > + template_desc->num_fields), GFP_NOFS); > > if (!*entry) > > return -ENOMEM; > > > > The same usage exists in ima_api.c: ima_alloc_init_template().  Did you want to make the change there as well? thanks, Mimi