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Commit 280ceaed authored by Oliver Neukum's avatar Oliver Neukum Committed by David S. Miller
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usbnet: sanity checking of packet sizes and device mtu 



After a reset packet sizes and device mtu can change and need
to be reevaluated to calculate queue sizes.
Malicious devices can set this to zero and we divide by it.
Introduce sanity checking.

Reported-and-tested-by: default avatar <syzbot+6102c120be558c885f04@syzkaller.appspotmail.com>
Signed-off-by: default avatarOliver Neukum <oneukum@suse.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent b41dae06

drivers/net/usb/usbnet.c

+3 −0
Original line number Diff line number Diff line
@@ -339,6 +339,8 @@ void usbnet_update_max_qlen(struct usbnet *dev) 
{

	enum usb_device_speed speed = dev->udev->speed;



	if (!dev->rx_urb_size || !dev->hard_mtu)

		goto insanity;

	switch (speed) {

	case USB_SPEED_HIGH:

		dev->rx_qlen = MAX_QUEUE_MEMORY / dev->rx_urb_size;
@@ -355,6 +357,7 @@ void usbnet_update_max_qlen(struct usbnet *dev) 
		dev->tx_qlen = 5 * MAX_QUEUE_MEMORY / dev->hard_mtu;

		break;

	default:

insanity:

		dev->rx_qlen = dev->tx_qlen = 4;

	}

}