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Commit 55416208 authored by Oliver Neukum's avatar Oliver Neukum Committed by Greg Kroah-Hartman
Browse files

usbnet: sanity checking of packet sizes and device mtu 



[ Upstream commit 280ceaed79f18db930c0cc8bb21f6493490bf29c ]

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>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent 96f23cb8

drivers/net/usb/usbnet.c

+3 −0
Original line number Diff line number Diff line
@@ -354,6 +354,8 @@ 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;
@@ -370,6 +372,7 @@ 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;

	}

}