[PATCH 02/11] Input: ims-pcu - fix use-after-free and double-free in disconnect

[Dmitry Torokhov <dmitry.torokhov@gmail.com>]

ims_pcu_disconnect() only intended to perform cleanup when the primary
(control) interface is unbound. However, it currently relies on the
interface class to distinguish between control and data interfaces.
A malicious device could present a data interface with the same class
as the control interface, leading to premature cleanup and potential
use-after-free or double-free.

Switch to verifying that the interface being disconnected is indeed
the control interface.

Fixes: 628329d52474 ("Input: add IMS Passenger Control Unit driver")
Cc: stable@vger.kernel.org
Reported-by: Sashiko bot <sashiko-bot@kernel.org>
Assisted-by: Gemini:gemini-3.1-pro
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
---
 drivers/input/misc/ims-pcu.c | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/drivers/input/misc/ims-pcu.c b/drivers/input/misc/ims-pcu.c
index 57d917387544..d0934d577b5e 100644
--- a/drivers/input/misc/ims-pcu.c
+++ b/drivers/input/misc/ims-pcu.c
@@ -2071,7 +2071,6 @@ static int ims_pcu_probe(struct usb_interface *intf,
 static void ims_pcu_disconnect(struct usb_interface *intf)
 {
 	struct ims_pcu *pcu = usb_get_intfdata(intf);
-	struct usb_host_interface *alt = intf->cur_altsetting;
 
 	usb_set_intfdata(intf, NULL);
 
@@ -2079,7 +2078,7 @@ static void ims_pcu_disconnect(struct usb_interface *intf)
 	 * See if we are dealing with control or data interface. The cleanup
 	 * happens when we unbind primary (control) interface.
 	 */
-	if (alt->desc.bInterfaceClass != USB_CLASS_COMM)
+	if (intf != pcu->ctrl_intf)
 		return;
 
 	ims_pcu_stop_io(pcu);
-- 
2.54.0.746.g67dd491aae-goog