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Date: Thu, 25 Jul 2013 20:38:32 +0300
From: Dan Carpenter <dan.carpenter@oracle.com>
To: walter harms <wharms@bfs.de>
Cc: Mauro Carvalho Chehab <m.chehab@samsung.com>,
	Antti Palosaari <crope@iki.fi>,
	Nickolai Zeldovich <nickolai@csail.mit.edu>,
	Peter Senna Tschudin <peter.senna@gmail.com>,
	Andy Shevchenko <andriy.shevchenko@linux.intel.com>,
	linux-media@vger.kernel.org, kernel-janitors@vger.kernel.org
Subject: Re: [patch] [media] bt8xx: info leak in ca_get_slot_info()
Message-ID: <20130725173832.GC5585@mwanda>
References: <20130725164621.GA6945@elgon.mountain>
 <51F16065.40804@bfs.de>
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On Thu, Jul 25, 2013 at 07:29:09PM +0200, walter harms wrote:
> 
> 
> Am 25.07.2013 18:46, schrieb Dan Carpenter:
> > p_ca_slot_info was allocated with kmalloc() so we need to clear it
> > before passing it to the user.
> > 
> > Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
> > 
> > diff --git a/drivers/media/pci/bt8xx/dst_ca.c b/drivers/media/pci/bt8xx/dst_ca.c
> > index 0e788fc..6b9dc3f 100644
> > --- a/drivers/media/pci/bt8xx/dst_ca.c
> > +++ b/drivers/media/pci/bt8xx/dst_ca.c
> > @@ -302,8 +302,11 @@ static int ca_get_slot_info(struct dst_state *state, struct ca_slot_info *p_ca_s
> >  		p_ca_slot_info->flags = CA_CI_MODULE_READY;
> >  		p_ca_slot_info->num = 1;
> >  		p_ca_slot_info->type = CA_CI;
> > -	} else
> > +	} else {
> >  		p_ca_slot_info->flags = 0;
> > +		p_ca_slot_info->num = 0;
> > +		p_ca_slot_info->type = 0;
> > +	}
> >  
> >  	if (copy_to_user(arg, p_ca_slot_info, sizeof (struct ca_slot_info)))
> >  		return -EFAULT;
> 
> note: i have no clue how p_ca_slot_info looks like,
> but to avoid information leaks via compiler padding etc. i could be more wise
> to do a  memset(p_ca_slot_info,0,sizeof (struct ca_slot_info))
> and then set the

There is no compiler padding.  My static checker looks for that.

regards,
dan carpenter