[PATCH] usb: gadget: max3420_udc: Fix out-of-bounds endpoint index access

[Seungjin Bae <eeodqql09@gmail.com>]

In the max3420_set_clear_feature() function, the endpoint index `id` can have a value from 0 to 15.
However, the udc->ep array is initialized with a maximum of 4 endpoints in max3420_eps_init().
If host sends a request with a wIndex greater than 3, the access to `udc->ep[id]` will go out-of-bounds,
leading to memory corruption or a potential kernel crash.
This bug was found by code inspection and has not been tested on hardware.

Fixes: 48ba02b2e2b1a ("usb: gadget: add udc driver for max3420")
Cc: stable@vger.kernel.org
Signed-off-by: Seungjin Bae <eeodqql09@gmail.com>
---
 drivers/usb/gadget/udc/max3420_udc.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/drivers/usb/gadget/udc/max3420_udc.c b/drivers/usb/gadget/udc/max3420_udc.c
index 7349ea774adf..e4ecc7f7f3be 100644
--- a/drivers/usb/gadget/udc/max3420_udc.c
+++ b/drivers/usb/gadget/udc/max3420_udc.c
@@ -596,6 +596,8 @@ static void max3420_set_clear_feature(struct max3420_udc *udc)
 			break;
 
 		id = udc->setup.wIndex & USB_ENDPOINT_NUMBER_MASK;
+		if (id >= MAX3420_MAX_EPS)
+			break;
 		ep = &udc->ep[id];
 
 		spin_lock_irqsave(&ep->lock, flags);
-- 
2.43.0