LKML Archive on lore.kernel.org
help / color / mirror / Atom feed
From: Mimi Zohar <zohar@linux.ibm.com>
To: "Gustavo A. R. Silva" <gustavo@embeddedor.com>,
	Dmitry Kasatkin <dmitry.kasatkin@gmail.com>,
	James Morris <jmorris@namei.org>,
	"Serge E. Hallyn" <serge@hallyn.com>
Cc: linux-integrity@vger.kernel.org,
	linux-security-module@vger.kernel.org,
	linux-kernel@vger.kernel.org
Subject: Re: [PATCH] ima: use struct_size() in kzalloc()
Date: Wed, 28 Aug 2019 23:45:55 -0400	[thread overview]
Message-ID: <1567050355.11493.3.camel@linux.ibm.com> (raw)
In-Reply-To: <671185b9-5c91-5235-b5ea-96d3449bf716@embeddedor.com>

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 <gustavo@embeddedor.com>
> > ---
> >  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


  parent reply	other threads:[~2019-08-29  3:46 UTC|newest]

Thread overview: 6+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-05-29 16:53 Gustavo A. R. Silva
2019-08-28 18:29 ` Gustavo A. R. Silva
2019-08-28 18:46   ` Mimi Zohar
2019-08-28 18:51     ` Gustavo A. R. Silva
2019-08-29  3:45   ` Mimi Zohar [this message]
2019-08-29 17:16     ` Gustavo A. R. Silva

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=1567050355.11493.3.camel@linux.ibm.com \
    --to=zohar@linux.ibm.com \
    --cc=dmitry.kasatkin@gmail.com \
    --cc=gustavo@embeddedor.com \
    --cc=jmorris@namei.org \
    --cc=linux-integrity@vger.kernel.org \
    --cc=linux-kernel@vger.kernel.org \
    --cc=linux-security-module@vger.kernel.org \
    --cc=serge@hallyn.com \
    --subject='Re: [PATCH] ima: use struct_size() in kzalloc()' \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link

This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).