Thread (8 messages) 8 messages, 4 authors, 2014-09-16

Re: [PATCH] net: can: usb: peak_usb: pcan_usb_core.c: Cleaning up missing null-terminate in conjunction with strncpy

From: Marc Kleine-Budde <mkl@pengutronix.de>
Date: 2014-09-15 08:42:41
Also in: linux-can, lkml

On 09/15/2014 10:28 AM, David Laight wrote:
From: Rickard Strandqvist
...
quoted
Replacing strncpy with strlcpy to avoid strings that lacks null terminate.
...
quoted
diff --git a/drivers/net/can/usb/peak_usb/pcan_usb_core.c
b/drivers/net/can/usb/peak_usb/pcan_usb_core.c
index 644e6ab..d4fe8ac 100644
--- a/drivers/net/can/usb/peak_usb/pcan_usb_core.c
+++ b/drivers/net/can/usb/peak_usb/pcan_usb_core.c
@@ -830,7 +830,7 @@ static void peak_usb_disconnect(struct usb_interface *intf)
 		char name[IFNAMSIZ];

 		dev->state &= ~PCAN_USB_STATE_CONNECTED;
-		strncpy(name, netdev->name, IFNAMSIZ);
+		strlcpy(name, netdev->name, IFNAMSIZ);

 		unregister_netdev(netdev);
 		free_candev(netdev);
Or:
	char name[sizeof netdev->name];
	memcpy(name, netdev->name, sizeof netdev->name);
I would be "sizeof(foo)" in kernel coding style, but let's have a look
at the original code:

                struct net_device *netdev = dev->netdev;
                char name[IFNAMSIZ];

                dev->state &= ~PCAN_USB_STATE_CONNECTED;
                strncpy(name, netdev->name, IFNAMSIZ);

                unregister_netdev(netdev);
                free_candev(netdev);

                kfree(dev->cmd_buf);
                dev->next_siblings = NULL;
                if (dev->adapter->dev_free)
                        dev->adapter->dev_free(dev);

                dev_info(&intf->dev, "%s removed\n", name);

I think it's save to use:

    dev_info(&intf->dev, "%s removed\n", netdev_name(dev->netdev));

instead of doing the str?cpy() in the first place. But why not use:

    netdev_info(dev->netdev, "removed\n");

Is the USB device information lost when using netdev_info()?

Marc

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