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authorAlan Stern <stern@rowland.harvard.edu>2016-08-23 15:32:51 -0400
committerSasha Levin <alexander.levin@verizon.com>2016-09-12 18:59:55 -0400
commite066faf1b61036126cbc3163fa370d4247e880dc (patch)
tree0399f3777921321daf53eba9c1762c86617fb11b
parent93c7ae51294639d51ef0f6fbc722daae0544f873 (diff)
downloadlwn-e066faf1b61036126cbc3163fa370d4247e880dc.tar.gz
lwn-e066faf1b61036126cbc3163fa370d4247e880dc.zip
USB: avoid left shift by -1
[ Upstream commit 53e5f36fbd2453ad69a3369a1db62dc06c30a4aa ] 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 <stern@rowland.harvard.edu> Reported-by: Vittorio Zecca <zeccav@gmail.com> Tested-by: Vittorio Zecca <zeccav@gmail.com> Suggested-by: Bjørn Mork <bjorn@mork.no> CC: <stable@vger.kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Signed-off-by: Sasha Levin <alexander.levin@verizon.com>
-rw-r--r--drivers/usb/core/devio.c16
1 files changed, 11 insertions, 5 deletions
diff --git a/drivers/usb/core/devio.c b/drivers/usb/core/devio.c
index a85eadff6bea..ea8ec9ceab68 100644
--- a/drivers/usb/core/devio.c
+++ b/drivers/usb/core/devio.c
@@ -1526,11 +1526,17 @@ 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++) {