Commit 280ceaed authored Sep 19, 2019 by Oliver Neukum Committed by David S. Miller Sep 19, 2019

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:  <syzbot+6102c120be558c885f04@syzkaller.appspotmail.com>
Signed-off-by: Oliver Neukum <oneukum@suse.com>
Signed-off-by: David 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;
		}
		}

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