linux-kernel - Re: [PATCH] staging: wilc1000: check for kmalloc allocation failures

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Date:   Mon, 26 Mar 2018 21:05:48 +0530
From:   Ajay Singh <ajay.kathat@...rochip.com>
To:     Colin King <colin.king@...onical.com>
CC:     Joe Perches <joe@...ches.com>,
        Aditya Shankar <aditya.shankar@...rochip.com>,
        Ganesh Krishna <ganesh.krishna@...rochip.com>,
        Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        <linux-wireless@...r.kernel.org>, <devel@...verdev.osuosl.org>,
        <kernel-janitors@...r.kernel.org>, <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH] staging: wilc1000: check for kmalloc allocation
 failures

Thanks for submitting the patch.

On Wed, 21 Mar 2018 13:03:18 -0700
Joe Perches <joe@...ches.com> wrote:

> On Wed, 2018-03-21 at 19:19 +0000, Colin King wrote:
> > From: Colin Ian King <colin.king@...onical.com>
> > 
> > There are three kmalloc allocations that are not null checked which
> > potentially could lead to null pointer dereference issues. Fix this
> > by adding null pointer return checks.
> 
> looks like all of these should be kmemdup or kstrdup
> 
> >  
> > @@ -951,6 +955,10 @@ static s32 handle_connect(struct wilc_vif *vif,
> >  	if (conn_attr->ssid) {
> >  		hif_drv->usr_conn_req.ssid = kmalloc(conn_attr->ssid_len + 1,
> >  						     GFP_KERNEL);
> > +		if (!hif_drv->usr_conn_req.ssid) {
> > +			result = -ENOMEM;
> > +			goto error;
> > +		}
> >  		memcpy(hif_drv->usr_conn_req.ssid,
> >  		       conn_attr->ssid,
> >  		       conn_attr->ssid_len);

With this changes the Coverity reported warning is handled correctly.

For further improvement to the patch, as Joe Perches suggested, its better
to make use of kmemdup instead of kmalloc & memcpy. As kstrdup requires the
source string to be NULL terminated('\0') and conn_attr->ssid might not  
contains the '\0' terminated string. So kmemdup with length of 
'conn_attr->ssid_len' can be used instead.

Please include the changes by using kmemdup() for all kmalloc/memcpy in
this patch.



Regards,
Ajay