USB: musb: be careful with 64K+ transfer lengths, host side

Feeding 32-bit length cast down to 'u16' to min() to calculate the FIFO
count in musb_host_tx() risks sending a short packet prematurely for
transfer sizes over 64 KB.

Similarly, although data transfer size shouldn't exceed 65535 bytes for
the control endpoint, making musb_h_ep0_continue() more robust WRT URBs
with possibly oversized buffer will not hurt either...

Signed-off-by: Sergei Shtylyov <sshtylyov@ru.mvista.com>
Signed-off-by: David Brownell <dbrownell@users.sourceforge.net>
Cc: Felipe Balbi <felipe.balbi@nokia.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

diff --git a/drivers/usb/musb/musb_host.c b/drivers/usb/musb/musb_host.c
index fc79e76..23d3890 100644 (file)
--- a/drivers/usb/musb/musb_host.c
+++ b/drivers/usb/musb/musb_host.c
@@ -937,8 +937,8 @@ static bool musb_h_ep0_continue(struct musb *musb, u16 len, struct urb *urb)
        switch (musb->ep0_stage) {
        case MUSB_EP0_IN:
                fifo_dest = urb->transfer_buffer + urb->actual_length;
-               fifo_count = min(len, ((u16) (urb->transfer_buffer_length
-                                       - urb->actual_length)));
+               fifo_count = min_t(size_t, len, urb->transfer_buffer_length -
+                                  urb->actual_length);
                if (fifo_count < len)
                        urb->status = -EOVERFLOW;
 
@@ -971,10 +971,9 @@ static bool musb_h_ep0_continue(struct musb *musb, u16 len, struct urb *urb)
                }
                /* FALLTHROUGH */
        case MUSB_EP0_OUT:
-               fifo_count = min(qh->maxpacket, ((u16)
-                               (urb->transfer_buffer_length
-                               - urb->actual_length)));
-
+               fifo_count = min_t(size_t, qh->maxpacket,
+                                  urb->transfer_buffer_length -
+                                  urb->actual_length);
                if (fifo_count) {
                        fifo_dest = (u8 *) (urb->transfer_buffer
                                        + urb->actual_length);
@@ -1304,7 +1303,8 @@ void musb_host_tx(struct musb *musb, u8 epnum)
                 * packets before updating TXCSR ... other docs disagree ...
                 */
                /* PIO:  start next packet in this URB */
-               wLength = min(qh->maxpacket, (u16) wLength);
+               if (wLength > qh->maxpacket)
+                       wLength = qh->maxpacket;
                musb_write_fifo(hw_ep, wLength, buf);
                qh->segsize = wLength;