On 18.10.21 20:55, syzbot wrote: > Hello, > > syzbot found the following issue on: > > HEAD commit: 660a92a59b9e usb: xhci: Enable runtime-pm by default on AM.. > git tree: https://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb.git usb-testing > console output: https://syzkaller.appspot.com/x/log.txt?x=1506ccf0b00000 > kernel config: https://syzkaller.appspot.com/x/.config?x=5016916cdc0a4a84 > dashboard link: https://syzkaller.appspot.com/bug?extid=a6ec4dd9d38cb9261a77 > compiler: gcc (Debian 10.2.1-6) 10.2.1 20210110, GNU ld (GNU Binutils for Debian) 2.35.2 > syz repro: https://syzkaller.appspot.com/x/repro.syz?x=11308734b00000 > C reproducer: https://syzkaller.appspot.com/x/repro.c?x=12f56f68b00000 > > IMPORTANT: if you fix the issue, please add the following tag to the commit: > Reported-by: syzbot+a6ec4dd9d38cb9261a77@xxxxxxxxxxxxxxxxxxxxxxxxx #syz test https://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb.git c03fb16bafdf
>From a5270791d4480e9a6bc009c69a4454039aa160e7 Mon Sep 17 00:00:00 2001 From: Oliver Neukum <oneukum@xxxxxxxx> Date: Tue, 19 Oct 2021 10:02:42 +0200 Subject: [PATCH] usbnet: sanity check for maxpacket We cannot leave maxpacket at 0 because we divide by it. Devices that give us a 0 there are unlikely to work, but let's assume a 1, so we don't oops and a least try to operate. Signed-off-by: Oliver Neukum <oneukum@xxxxxxxx> Reported-by: syzbot+76bb1d34ffa0adc03baa@xxxxxxxxxxxxxxxxxxxxxxxxx --- 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 840c1c2ab16a..2bdc3e0c1579 100644 --- a/drivers/net/usb/usbnet.c +++ b/drivers/net/usb/usbnet.c @@ -1788,6 +1788,9 @@ usbnet_probe (struct usb_interface *udev, const struct usb_device_id *prod) if (!dev->rx_urb_size) dev->rx_urb_size = dev->hard_mtu; dev->maxpacket = usb_maxpacket (dev->udev, dev->out, 1); + if (dev->maxpacket == 0) + /* that is a strange device */ + dev->maxpacket = 1; /* let userspace know we have a random address */ if (ether_addr_equal(net->dev_addr, node_id)) -- 2.26.2
