USB: ehci: paranoia, reject large control transfers

Some EHCI fault paths with large control transfers aren't coded.  Avoid
problems by rejecting transfers that may need two qTDs (16+ KB).  This is
mostly paranoia; even 4 KB transfers are rare, and most HCDs use lower
limits (so it's unlikely anyone would ever try such a thing).

Signed-off-by: David Brownell <dbrownell@users.sourceforge.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

diff --git a/drivers/usb/host/ehci-hcd.c b/drivers/usb/host/ehci-hcd.c
index 8c3e860..a02dcff 100644 (file)
--- a/drivers/usb/host/ehci-hcd.c
+++ b/drivers/usb/host/ehci-hcd.c
@@ -764,8 +764,14 @@ static int ehci_urb_enqueue (
        INIT_LIST_HEAD (&qtd_list);
 
        switch (usb_pipetype (urb->pipe)) {
-       // case PIPE_CONTROL:
-       // case PIPE_BULK:
+       case PIPE_CONTROL:
+               /* qh_completions() code doesn't handle all the fault cases
+                * in multi-TD control transfers.  Even 1KB is rare anyway.
+                */
+               if (urb->transfer_buffer_length > (16 * 1024))
+                       return -EMSGSIZE;
+               /* FALLTHROUGH */
+       /* case PIPE_BULK: */
        default:
                if (!qh_urb_transaction (ehci, urb, &qtd_list, mem_flags))
                        return -ENOMEM;