linux-kernel - [PATCH 5.3 079/193] can: mcba_usb: fix use-after-free on disconnect

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Date:   Mon, 11 Nov 2019 19:27:41 +0100
From:   Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To:     linux-kernel@...r.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        stable@...r.kernel.org,
        Remigiusz Kołłątaj 
        <remigiusz.kollataj@...ica.com>,
        syzbot+e29b17e5042bbc56fae9@...kaller.appspotmail.com,
        Johan Hovold <johan@...nel.org>,
        Marc Kleine-Budde <mkl@...gutronix.de>
Subject: [PATCH 5.3 079/193] can: mcba_usb: fix use-after-free on disconnect

From: Johan Hovold <johan@...nel.org>

commit 4d6636498c41891d0482a914dd570343a838ad79 upstream.

The driver was accessing its driver data after having freed it.

Fixes: 51f3baad7de9 ("can: mcba_usb: Add support for Microchip CAN BUS Analyzer")
Cc: stable <stable@...r.kernel.org>     # 4.12
Cc: Remigiusz Kołłątaj <remigiusz.kollataj@...ica.com>
Reported-by: syzbot+e29b17e5042bbc56fae9@...kaller.appspotmail.com
Signed-off-by: Johan Hovold <johan@...nel.org>
Signed-off-by: Marc Kleine-Budde <mkl@...gutronix.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@...uxfoundation.org>

---
 drivers/net/can/usb/mcba_usb.c |    3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

--- a/drivers/net/can/usb/mcba_usb.c
+++ b/drivers/net/can/usb/mcba_usb.c
@@ -876,9 +876,8 @@ static void mcba_usb_disconnect(struct u
 	netdev_info(priv->netdev, "device disconnected\n");
 
 	unregister_candev(priv->netdev);
-	free_candev(priv->netdev);
-
 	mcba_urb_unlink(priv);
+	free_candev(priv->netdev);
 }
 
 static struct usb_driver mcba_usb_driver = {