From 53e5f36fbd2453ad69a3369a1db62dc06c30a4aa Mon Sep 17 00:00:00 2001 From: Alan Stern Date: Tue, 23 Aug 2016 15:32:51 -0400 Subject: USB: avoid left shift by -1 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit UBSAN complains about a left shift by -1 in proc_do_submiturb(). This can occur when an URB is submitted for a bulk or control endpoint on a high-speed device, since the code doesn't bother to check the endpoint type; normally only interrupt or isochronous endpoints have a nonzero bInterval value. Aside from the fact that the operation is illegal, it shouldn't matter because the result isn't used. Still, in theory it could cause a hardware exception or other problem, so we should work around it. This patch avoids doing the left shift unless the shift amount is >= 0. The same piece of code has another problem. When checking the device speed (the exponential encoding for interrupt endpoints is used only by high-speed or faster devices), we need to look for speed >= USB_SPEED_SUPER as well as speed == USB_SPEED HIGH. The patch adds this check. Signed-off-by: Alan Stern Reported-by: Vittorio Zecca Tested-by: Vittorio Zecca Suggested-by: Bjørn Mork CC: Signed-off-by: Greg Kroah-Hartman --- drivers/usb/core/devio.c | 16 +++++++++++----- 1 file changed, 11 insertions(+), 5 deletions(-) (limited to 'drivers/usb/core/devio.c') diff --git a/drivers/usb/core/devio.c b/drivers/usb/core/devio.c index e6a6d67c8705..09c8d9ca61ae 100644 --- a/drivers/usb/core/devio.c +++ b/drivers/usb/core/devio.c @@ -1709,11 +1709,17 @@ static int proc_do_submiturb(struct usb_dev_state *ps, struct usbdevfs_urb *uurb as->urb->start_frame = uurb->start_frame; as->urb->number_of_packets = number_of_packets; as->urb->stream_id = stream_id; - if (uurb->type == USBDEVFS_URB_TYPE_ISO || - ps->dev->speed == USB_SPEED_HIGH) - as->urb->interval = 1 << min(15, ep->desc.bInterval - 1); - else - as->urb->interval = ep->desc.bInterval; + + if (ep->desc.bInterval) { + if (uurb->type == USBDEVFS_URB_TYPE_ISO || + ps->dev->speed == USB_SPEED_HIGH || + ps->dev->speed >= USB_SPEED_SUPER) + as->urb->interval = 1 << + min(15, ep->desc.bInterval - 1); + else + as->urb->interval = ep->desc.bInterval; + } + as->urb->context = as; as->urb->complete = async_completed; for (totlen = u = 0; u < number_of_packets; u++) { -- cgit v1.2.3