From mboxrd@z Thu Jan  1 00:00:00 1970
From: Eric Dumazet <eric.dumazet@gmail.com>
Subject: Re: [PATCH net-next] sockopt: Make SO_BINDTODEVICE readable
Date: Mon, 22 Oct 2012 22:45:02 +0200
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Cc: Pavel Emelyanov <xemul@parallels.com>,
	Linux Netdev List <netdev@vger.kernel.org>,
	David Miller <davem@davemloft.net>
To: Brian Haley <brian.haley@hp.com>
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On Mon, 2012-10-22 at 14:04 -0400, Brian Haley wrote:

> +	char devname[IFNAMSIZ];
> +
> +	ret = 0;
> +	if (sk->sk_bound_dev_if == 0)
> +		goto out;
> +
> +	ret = -EINVAL;
> +	if (len < IFNAMSIZ)
> +		goto out;
> +	if (len > IFNAMSIZ)
> +		len = IFNAMSIZ;
> +
> +	rcu_read_lock();
> +	dev = dev_get_by_index_rcu(net, sk->sk_bound_dev_if);
> +	if (dev)
> +		strcpy(dev->name, devname);
> +	rcu_read_unlock();
> +	ret = -ENODEV;

You probably meant

	strcpy(devname, dev->name)

By the way, this is not really safe in case device is renamed