usb: usbip: vudc: fix left shift overflow

commit 238b7bd91b16d5a08326f858db42229b212e53d8 upstream.

In v_recv_cmd_submit(), urb_p->urb->pipe has the type unsigned int
(which is 32-bit long on x86_64) but 11<<30 results in a 34-bit integer.
Therefore the 2 leading bits are truncated and

    urb_p->urb->pipe &= ~(11 << 30);

has the same meaning as

    urb_p->urb->pipe &= ~(3 << 30);

This second statement seems to be how the code was intended to be
written, as PIPE_ constants have values between 0 and 3.

The overflow has been detected with a clang warning:

    drivers/usb/usbip/vudc_rx.c:145:27: warning: signed shift result
    (0x2C0000000) requires 35 bits to represent, but 'int' only has 32
    bits [-Wshift-overflow]
            urb_p->urb->pipe &= ~(11 << 30);
                                  ~~ ^  ~~

Fixes: 79c02cb1fd5c ("usbip: vudc: Add vudc_rx")
Signed-off-by: Nicolas Iooss <nicolas.iooss_linux@m4x.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/usb/usbip/vudc_rx.c b/drivers/usb/usbip/vudc_rx.c
index 344bd9473475619020335ffdc9b392c9bc606e82..e429b59f6f8a634f66900f367feeb782bec10de5 100644 (file)
--- a/drivers/usb/usbip/vudc_rx.c
+++ b/drivers/usb/usbip/vudc_rx.c
@@ -142,7 +142,7 @@ static int v_recv_cmd_submit(struct vudc *udc,
        urb_p->urb->status = -EINPROGRESS;
 
        /* FIXME: more pipe setup to please usbip_common */
-       urb_p->urb->pipe &= ~(11 << 30);
+       urb_p->urb->pipe &= ~(3 << 30);
        switch (urb_p->ep->type) {
        case USB_ENDPOINT_XFER_BULK:
                urb_p->urb->pipe |= (PIPE_BULK << 30);