linux-kernel - [PATCH 1/2] can: mcba_usb: fix use-after-free on disconnect

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Message-Id: <20191001102914.4567-2-johan@kernel.org>
Date:   Tue,  1 Oct 2019 12:29:13 +0200
From:   Johan Hovold <johan@...nel.org>
To:     Wolfgang Grandegger <wg@...ndegger.com>,
        Marc Kleine-Budde <mkl@...gutronix.de>
Cc:     "David S. Miller" <davem@...emloft.net>, linux-can@...r.kernel.org,
        netdev@...r.kernel.org, linux-kernel@...r.kernel.org,
        linux-usb@...r.kernel.org, Johan Hovold <johan@...nel.org>,
        stable <stable@...r.kernel.org>,
        Remigiusz Kołłątaj 
        <remigiusz.kollataj@...ica.com>,
        syzbot+e29b17e5042bbc56fae9@...kaller.appspotmail.com
Subject: [PATCH 1/2] can: mcba_usb: fix use-after-free on disconnect

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

diff --git a/drivers/net/can/usb/mcba_usb.c b/drivers/net/can/usb/mcba_usb.c
index 19a702ac49e4..21faa2ec4632 100644
--- 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 usb_interface *intf)
 	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 = {
-- 
2.23.0