Re: [patch] gru: info leak in gru_get_config_info()

[walter harms]

Am 21.04.2013 13:10, schrieb Dan Carpenter:
> The "info.fill" array isn't initialized so it can leak uninitialized
> stack information to user space.
> 
> Signed-off-by: Dan Carpenter <dan.carpenter@xxxxxxxxxx>
> 
> diff --git a/drivers/misc/sgi-gru/grufile.c b/drivers/misc/sgi-gru/grufile.c
> index 44d273c..ed5fc43 100644
> --- a/drivers/misc/sgi-gru/grufile.c
> +++ b/drivers/misc/sgi-gru/grufile.c
> @@ -176,6 +176,7 @@ static long gru_get_config_info(unsigned long arg)
>  	info.nodes = num_online_nodes();
>  	info.blades = info.nodes / nodesperblade;
>  	info.chiplets = GRU_CHIPLETS_PER_BLADE * info.blades;
> +	memset(&info.fill, 0, sizeof(info.fill));
>  

the other way around (clear first all bytes) looks more easy
in case someone will add more elements to the struct.

memset(&info, 0, sizeof(info));
info.nodes = num_online_nodes();
info.blades = info.nodes / nodesperblade;
....

re,
 wh


>  	if (copy_to_user((void __user *)arg, &info, sizeof(info)))
>  		return -EFAULT;
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