USB: mct_u232: add sanity checking in probe 39/76539/2
authorOliver Neukum <oneukum@suse.com>
Thu, 31 Mar 2016 16:04:24 +0000 (12:04 -0400)
committerSeung-Woo Kim <sw0312.kim@samsung.com>
Wed, 3 Aug 2016 02:35:21 +0000 (19:35 -0700)
commit 4e9a0b05257f29cf4b75f3209243ed71614d062e upstream.

An attack using the lack of sanity checking in probe is known. This
patch checks for the existence of a second port.

CVE-2016-3136

Signed-off-by: Oliver Neukum <ONeukum@suse.com>
CC: stable@vger.kernel.org
[johan: add error message ]
Signed-off-by: Johan Hovold <johan@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Willy Tarreau <w@1wt.eu>
Change-Id: Icd1c5482b10f647177c7793c93fc7b592df4e79e
Signed-off-by: Junghoon Kim <jhoon20.kim@samsung.com>
drivers/usb/serial/mct_u232.c

index 6a15adf..c14c29f 100644 (file)
@@ -377,14 +377,21 @@ static void mct_u232_msr_to_state(struct usb_serial_port *port,
 
 static int mct_u232_port_probe(struct usb_serial_port *port)
 {
+       struct usb_serial *serial = port->serial;
        struct mct_u232_private *priv;
 
+       /* check first to simplify error handling */
+       if (!serial->port[1] || !serial->port[1]->interrupt_in_urb) {
+               dev_err(&port->dev, "expected endpoint missing\n");
+               return -ENODEV;
+       }
+
        priv = kzalloc(sizeof(*priv), GFP_KERNEL);
        if (!priv)
                return -ENOMEM;
 
        /* Use second interrupt-in endpoint for reading. */
-       priv->read_urb = port->serial->port[1]->interrupt_in_urb;
+       priv->read_urb = serial->port[1]->interrupt_in_urb;
        priv->read_urb->context = port;
 
        spin_lock_init(&priv->lock);