From mboxrd@z Thu Jan  1 00:00:00 1970
From: walter harms <wharms@bfs.de>
Date: Thu, 25 Jul 2013 17:29:09 +0000
Subject: Re: [patch] [media] bt8xx: info leak in ca_get_slot_info()
Message-Id: <51F16065.40804@bfs.de>
List-Id: <kernel-janitors.vger.kernel.org>
References: <20130725164621.GA6945@elgon.mountain>
In-Reply-To: <20130725164621.GA6945@elgon.mountain>
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To: Dan Carpenter <dan.carpenter@oracle.com>
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



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
	p_ca_slot_info->flags = CA_CI_MODULE_READY;
	p_ca_slot_info->num = 1;
	p_ca_slot_info->type = CA_CI;

just my 2 cents,
re,
 wh