usb: gadget: f_tcm: Fix Get/SetInterface return value

commit 3b99708 upstream.

Check to make sure that the GetInterface and SetInterface are for valid
interface. Return proper alternate setting number on GetInterface.

Fixes: 0b8b1a1 ("usb: gadget: f_tcm: Provide support to get alternate setting in tcm function")
Cc: stable@vger.kernel.org
Signed-off-by: Thinh Nguyen <Thinh.Nguyen@synopsys.com>
Link: https://lore.kernel.org/r/ffd91b4640945ea4d3b4f4091cf1abbdbd9cf4fc.1733876548.git.Thinh.Nguyen@synopsys.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Author: Thinh Nguyen

drivers/usb/gadget/function/f_tcm.c

@@ -2051,9 +2051,14 @@ static void tcm_delayed_set_alt(struct work_struct *wq)
 
 static int tcm_get_alt(struct usb_function *f, unsigned intf)
 {
-	if (intf == bot_intf_desc.bInterfaceNumber)
+	struct f_uas *fu = to_f_uas(f);
+
+	if (fu->iface != intf)
+		return -EOPNOTSUPP;
+
+	if (fu->flags & USBG_IS_BOT)
 		return USB_G_ALT_INT_BBB;
-	if (intf == uasp_intf_desc.bInterfaceNumber)
+	else if (fu->flags & USBG_IS_UAS)
 		return USB_G_ALT_INT_UAS;
 
 	return -EOPNOTSUPP;
@@ -2063,6 +2068,9 @@ static int tcm_set_alt(struct usb_function *f, unsigned intf, unsigned alt)
 {
 	struct f_uas *fu = to_f_uas(f);
 
+	if (fu->iface != intf)
+		return -EOPNOTSUPP;
+
 	if ((alt == USB_G_ALT_INT_BBB) || (alt == USB_G_ALT_INT_UAS)) {
 		struct guas_setup_wq *work;