This is a note to let you know that I've just added the patch titled
USB: avoid left shift by -1
to my usb git tree which can be found at
git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb.git
in the usb-linus branch.
The patch will show up in the next release of the linux-next tree
(usually sometime within the next 24 hours during the week.)
The patch will hopefully also be merged in Linus's tree for the
next -rc kernel release.
If you have any questions about this process, please let me know.
>From 53e5f36fbd2453ad69a3369a1db62dc06c30a4aa Mon Sep 17 00:00:00 2001
From: Alan Stern <stern@xxxxxxxxxxxxxxxxxxx>
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 <stern@xxxxxxxxxxxxxxxxxxx>
Reported-by: Vittorio Zecca <zeccav@xxxxxxxxx>
Tested-by: Vittorio Zecca <zeccav@xxxxxxxxx>
Suggested-by: Bjørn Mork <bjorn@xxxxxxx>
CC: <stable@xxxxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
drivers/usb/core/devio.c | 16 +++++++++++-----
1 file changed, 11 insertions(+), 5 deletions(-)
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++) {
--
2.9.3
--
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