Am Montag, den 16.09.2019, 06:29 -0700 schrieb syzbot:
> Hello,
>
> syzbot found the following crash on:
>
> HEAD commit: f0df5c1b usb-fuzzer: main usb gadget fuzzer driver
> git tree: https://github.com/google/kasan.git usb-fuzzer
> console output: https://syzkaller.appspot.com/x/log.txt?x=117659fa600000
> kernel config: https://syzkaller.appspot.com/x/.config?x=5c6633fa4ed00be5
> dashboard link: https://syzkaller.appspot.com/bug?extid=6102c120be558c885f04
> compiler: gcc (GCC) 9.0.0 20181231 (experimental)
> syz repro: https://syzkaller.appspot.com/x/repro.syz?x=12107ba9600000
> C reproducer: https://syzkaller.appspot.com/x/repro.c?x=146014e6600000
>
> IMPORTANT: if you fix the bug, please add the following tag to the commit:
> Reported-by: syzbot+6102c120be558c885f04@xxxxxxxxxxxxxxxxxxxxxxxxx
#syz test: https://github.com/google/kasan.git f0df5c1b
From 57c2443b2a7678a6f7f6437f741f49f06a5104fb Mon Sep 17 00:00:00 2001
From: Oliver Neukum <oneukum@xxxxxxxx>
Date: Tue, 17 Sep 2019 11:51:55 +0200
Subject: [PATCH] usbnet: sanity checking of packet sizes
Malicious devices can set this to zero and we divide by it.
Introduce sanity checking.
Signed-off-by: Oliver Neukum <oneukum@xxxxxxxx>
---
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
