USB: quatech2: fix use-after-free in TIOCMIWAIT
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.
Cc: stable <stable@vger.kernel.org>
Signed-off-by: Johan Hovold <jhovold@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
diff --git a/drivers/usb/serial/quatech2.c b/drivers/usb/serial/quatech2.c
index d643a4d..75f125d 100644
--- a/drivers/usb/serial/quatech2.c
+++ b/drivers/usb/serial/quatech2.c
@@ -128,7 +128,6 @@
u8 shadowLSR;
u8 shadowMSR;
- wait_queue_head_t delta_msr_wait; /* Used for TIOCMIWAIT */
struct async_icount icount;
struct usb_serial_port *port;
@@ -506,8 +505,9 @@
spin_unlock_irqrestore(&priv->lock, flags);
while (1) {
- wait_event_interruptible(priv->delta_msr_wait,
- ((priv->icount.rng != prev.rng) ||
+ wait_event_interruptible(port->delta_msr_wait,
+ (port->serial->disconnected ||
+ (priv->icount.rng != prev.rng) ||
(priv->icount.dsr != prev.dsr) ||
(priv->icount.dcd != prev.dcd) ||
(priv->icount.cts != prev.cts)));
@@ -515,6 +515,9 @@
if (signal_pending(current))
return -ERESTARTSYS;
+ if (port->serial->disconnected)
+ return -EIO;
+
spin_lock_irqsave(&priv->lock, flags);
cur = priv->icount;
spin_unlock_irqrestore(&priv->lock, flags);
@@ -827,7 +830,6 @@
spin_lock_init(&port_priv->lock);
spin_lock_init(&port_priv->urb_lock);
- init_waitqueue_head(&port_priv->delta_msr_wait);
port_priv->port = port;
port_priv->write_urb = usb_alloc_urb(0, GFP_KERNEL);
@@ -970,7 +972,7 @@
if (newMSR & UART_MSR_TERI)
port_priv->icount.rng++;
- wake_up_interruptible(&port_priv->delta_msr_wait);
+ wake_up_interruptible(&port->delta_msr_wait);
}
}