USB: ark3116: fix use-after-free in TIOCMIWAIT

commit 5018860321dc7a9e50a75d5f319bc981298fb5b7 upstream.

Use the port wait queue and make sure to check the serial disconnected
flag before accessing private port data after waking up.

This is is needed as the private port data (including the wait queue
itself) can be gone when waking up after a disconnect.

Signed-off-by: Johan Hovold <jhovold@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/usb/serial/ark3116.c b/drivers/usb/serial/ark3116.c
index a88882c0e2376283a015d38732096472a50fb5f7..0b44e45e42ad1b8821b5698d6213d1eafc297774 100644 (file)
--- a/drivers/usb/serial/ark3116.c
+++ b/drivers/usb/serial/ark3116.c
@@ -62,7 +62,6 @@ static int is_irda(struct usb_serial *serial)
 }
 
 struct ark3116_private {
-       wait_queue_head_t       delta_msr_wait;
        struct async_icount     icount;
        int                     irda;   /* 1 for irda device */
 
@@ -146,7 +145,6 @@ static int ark3116_port_probe(struct usb_serial_port *port)
        if (!priv)
                return -ENOMEM;
 
-       init_waitqueue_head(&priv->delta_msr_wait);
        mutex_init(&priv->hw_lock);
        spin_lock_init(&priv->status_lock);
 
@@ -456,10 +454,14 @@ static int ark3116_ioctl(struct tty_struct *tty,
        case TIOCMIWAIT:
                for (;;) {
                        struct async_icount prev = priv->icount;
-                       interruptible_sleep_on(&priv->delta_msr_wait);
+                       interruptible_sleep_on(&port->delta_msr_wait);
                        /* see if a signal did it */
                        if (signal_pending(current))
                                return -ERESTARTSYS;
+
+                       if (port->serial->disconnected)
+                               return -EIO;
+
                        if ((prev.rng == priv->icount.rng) &&
                            (prev.dsr == priv->icount.dsr) &&
                            (prev.dcd == priv->icount.dcd) &&
@@ -580,7 +582,7 @@ static void ark3116_update_msr(struct usb_serial_port *port, __u8 msr)
                        priv->icount.dcd++;
                if (msr & UART_MSR_TERI)
                        priv->icount.rng++;
-               wake_up_interruptible(&priv->delta_msr_wait);
+               wake_up_interruptible(&port->delta_msr_wait);
        }
 }