Re: [PATCH v2] drivers/net/usb/hso.c: prevent readinguninitialized memory

[Steven Rostedt]

On Wed, Sep 15, 2010 at 05:43:28PM -0400, Dan Rosenberg wrote:
> Fixed formatting (tabs and line breaks).
> 
> The TIOCGICOUNT device ioctl allows unprivileged users to read
> uninitialized stack memory, because the "reserved" member of the
> serial_icounter_struct struct declared on the stack in hso_get_count()
> is not altered or zeroed before being copied back to the user.  This
> patch takes care of it.
> 
> Signed-off-by: Dan Rosenberg <dan.j.rosenberg@xxxxxxxxx>
> 
> --- linux-2.6.35.4.orig/drivers/net/usb/hso.c	2010-08-26 19:47:12.000000000 -0400
> +++ linux-2.6.35.4/drivers/net/usb/hso.c	2010-09-14 21:26:18.477585183 -0400
> @@ -1653,6 +1653,8 @@ static int hso_get_count(struct hso_seri
>  	struct uart_icount cnow;
>  	struct hso_tiocmget  *tiocmget = serial->tiocmget;
>  
> +	memset(&icount, 0, sizeof(struct serial_icounter_struct));
> +

Move the above to after the spinlocks.

-- Steve

>  	if (!tiocmget)
>  		 return -ENOENT;
>  	spin_lock_irq(&serial->serial_lock);
> 
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