Re: [PATCH net-next] sockopt: Make SO_BINDTODEVICE readable

On 10/23/2012 12:45 AM, Eric Dumazet wrote:

On Mon, 2012-10-22 at 14:04 -0400, Brian Haley wrote:

quoted

+	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

Good point, actually. Getting a device name may be not very safe in terms of --
once we have the name there's no 100% guarantee, that this name corresponds to the
actual device the socket is bound to (it could be renamed after we strcpy-ed its
name). This problem doesn't exist when we get device index, as it cannot be changed.

Thanks,
Pavel