Re: [PATCH] sb1000: prevent a potential NULL pointer dereference in sb1000_dev_ioctl()

[Domen Puncer <domen@coderock.org>]

On 29/07/07 00:02 +0200, Jesper Juhl wrote:
> Hi,
> 
> Here's a small patch, prompted by a find by the Coverity checker, 
> that removes a potential NULL pointer dereference from 
> drivers/net/sb1000.c::sb1000_dev_ioctl().
> The checker spotted that we do a NULL test of 'dev', yet we 
> dereference the pointer prior to that check.
> This patch simply moves the dereference after the NULL test.

But... it can't be called without a valid 'dev', no?
A quick 'grep do_ioctl net/' confirms that all calls are in
the form of 'dev->do_ioctl(dev, ...'.


	Domen

	
> @@ -991,11 +991,13 @@ static int sb1000_dev_ioctl(struct net_device *dev, struct ifreq *ifr, int cmd)
>  	short PID[4];
>  	int ioaddr[2], status, frequency;
>  	unsigned int stats[5];
> -	struct sb1000_private *lp = netdev_priv(dev);
> +	struct sb1000_private *lp;
>  
>  	if (!(dev && dev->flags & IFF_UP))
>  		return -ENODEV;
>  
> +	lp = netdev_priv(dev);
> +
>  	ioaddr[0] = dev->base_addr;
>  	/* mem_start holds the second I/O address */
>  	ioaddr[1] = dev->mem_start;
>