[PATCH v2 1/1] usb: musb: gadget: misplaced out of bounds check

[Heinrich Schuchardt]

musb->endpoints[] has array size MUSB_C_NUM_EPS.
We must check array bounds before accessing the array and not afterwards.

Signed-off-by: Heinrich Schuchardt <xypron.g...@gmx.de>
---
v2
        Only the 4 low bits of epnum are relevant for indexing. 
---
 drivers/usb/musb/musb_gadget_ep0.c | 9 +++++++--
 1 file changed, 7 insertions(+), 2 deletions(-)

diff --git a/drivers/usb/musb/musb_gadget_ep0.c 
b/drivers/usb/musb/musb_gadget_ep0.c
index 18da4873e52e..96b0fa12f729 100644
--- a/drivers/usb/musb/musb_gadget_ep0.c
+++ b/drivers/usb/musb/musb_gadget_ep0.c
@@ -89,15 +89,20 @@ static int service_tx_status_request(
                }
 
                is_in = epnum & USB_DIR_IN;
+               epnum &= 0x0f;
+               if (epnum >= MUSB_C_NUM_EPS) {
+                       handled = -EINVAL;
+                       break;
+               }
+
                if (is_in) {
-                       epnum &= 0x0f;
                        ep = &musb->endpoints[epnum].ep_in;
                } else {
                        ep = &musb->endpoints[epnum].ep_out;
                }
                regs = musb->endpoints[epnum].regs;
 
-               if (epnum >= MUSB_C_NUM_EPS || !ep->desc) {
+               if (!ep->desc) {
                        handled = -EINVAL;
                        break;
                }
-- 
2.16.2

--
To unsubscribe from this list: send the line "unsubscribe linux-usb" in
the body of a message to majord...@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html