usb: gadget: composite: avoid access beyond array max length

One of the USB CV MSC tests issues Get Max LUN request with
invalid wIndex (wIndex = 65535) parameter.

Add proper handling to prevent array index out of bounds issue.

Signed-off-by: Maulik Mankad <maulik@ti.com>
Cc: David Brownell <david-b@pacbell.net>
Acked-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

1 files changed, 3 insertions, 2 deletions

diff --git a/drivers/usb/gadget/composite.c b/drivers/usb/gadget/composite.c
index f6ff8456d52d..1ba4befe336b 100644
--- a/drivers/usb/gadget/composite.c
+++ b/drivers/usb/gadget/composite.c
@@ -928,8 +928,9 @@ unknown:
                  */
                 switch (ctrl->bRequestType & USB_RECIP_MASK) {
                 case USB_RECIP_INTERFACE:
-                        if (cdev->config)
-                                f = cdev->config->interface[intf];
+                        if (!cdev->config || w_index >= MAX_CONFIG_INTERFACES)
+                                break;
+                        f = cdev->config->interface[intf];
                         break;
 
                 case USB_RECIP_ENDPOINT: