On Tue, Oct 19, 2021 at 10:14:20AM +0200, Oliver Neukum wrote: > > On 19.10.21 05:17, syzbot wrote: > > Hello, > > > > syzbot found the following issue on: > > > > HEAD commit: c03fb16bafdf Merge 5.15-rc6 into usb-next > > 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=12d48f1f300000 > > kernel config: https://syzkaller.appspot.com/x/.config?x=c27d285bdb7457e2 > > dashboard link: https://syzkaller.appspot.com/bug?extid=76bb1d34ffa0adc03baa > > 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=14fe6decb00000 > > C reproducer: https://syzkaller.appspot.com/x/repro.c?x=15c7bcaf300000 > > > > IMPORTANT: if you fix the issue, please add the following tag to the commit: > > Reported-by: syzbot+76bb1d34ffa0adc03baa@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; Just bail out; what can you do with a 1-byte packet size? Also compare usbnet_get_endpoints() where such endpoints are ignored. Johan
