From: Anant Thazhemadam <anant.thazhemadam@xxxxxxxxx> commit e1f13c879a7c21bd207dc6242455e8e3a1e88b40 upstream. While finding usb endpoints in vmk80xx_find_usb_endpoints(), check if wMaxPacketSize = 0 for the endpoints found. Some devices have isochronous endpoints that have wMaxPacketSize = 0 (as required by the USB-2 spec). However, since this doesn't apply here, wMaxPacketSize = 0 can be considered to be invalid. Reported-by: syzbot+009f546aa1370056b1c2@xxxxxxxxxxxxxxxxxxxxxxxxx Tested-by: syzbot+009f546aa1370056b1c2@xxxxxxxxxxxxxxxxxxxxxxxxx Signed-off-by: Anant Thazhemadam <anant.thazhemadam@xxxxxxxxx> Cc: stable <stable@xxxxxxxxxxxxxxx> Link: https://lore.kernel.org/r/20201010082933.5417-1-anant.thazhemadam@xxxxxxxxx Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- drivers/staging/comedi/drivers/vmk80xx.c | 3 +++ 1 file changed, 3 insertions(+) --- a/drivers/staging/comedi/drivers/vmk80xx.c +++ b/drivers/staging/comedi/drivers/vmk80xx.c @@ -676,6 +676,9 @@ static int vmk80xx_find_usb_endpoints(st if (!devpriv->ep_rx || !devpriv->ep_tx) return -ENODEV; + if (!usb_endpoint_maxp(devpriv->ep_rx) || !usb_endpoint_maxp(devpriv->ep_tx)) + return -EINVAL; + return 0; }
