From 280ceaed79f18db930c0cc8bb21f6493490bf29c Mon Sep 17 00:00:00 2001
From: Oliver Neukum <oneukum@suse.com>
Date: Thu, 19 Sep 2019 10:23:08 +0200
Subject: [PATCH] usbnet: sanity checking of packet sizes and device mtu
Git-commit: 280ceaed79f18db930c0cc8bb21f6493490bf29c
Patch-mainline: v5.4-rc1
References: bsc#1051510
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>
Acked-by: Takashi Iwai <tiwai@suse.de>
---
drivers/net/usb/usbnet.c | 3 +++
1 file changed, 3 insertions(+)
diff --git a/drivers/net/usb/usbnet.c b/drivers/net/usb/usbnet.c
index 58952a79b05f..e44849499b89 100644
--- a/drivers/net/usb/usbnet.c
+++ b/drivers/net/usb/usbnet.c
@@ -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;
}
}
--
2.16.4