USB: ch341: 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/ch341.c b/drivers/usb/serial/ch341.c
index d255f66..07d4650 100644
--- a/drivers/usb/serial/ch341.c
+++ b/drivers/usb/serial/ch341.c
@@ -80,7 +80,6 @@
struct ch341_private {
spinlock_t lock; /* access lock */
- wait_queue_head_t delta_msr_wait; /* wait queue for modem status */
unsigned baud_rate; /* set baud rate */
u8 line_control; /* set line control value RTS/DTR */
u8 line_status; /* active status of modem control inputs */
@@ -252,7 +251,6 @@
return -ENOMEM;
spin_lock_init(&priv->lock);
- init_waitqueue_head(&priv->delta_msr_wait);
priv->baud_rate = DEFAULT_BAUD_RATE;
priv->line_control = CH341_BIT_RTS | CH341_BIT_DTR;
@@ -298,7 +296,7 @@
priv->line_control &= ~(CH341_BIT_RTS | CH341_BIT_DTR);
spin_unlock_irqrestore(&priv->lock, flags);
ch341_set_handshake(port->serial->dev, priv->line_control);
- wake_up_interruptible(&priv->delta_msr_wait);
+ wake_up_interruptible(&port->delta_msr_wait);
}
static void ch341_close(struct usb_serial_port *port)
@@ -491,7 +489,7 @@
tty_kref_put(tty);
}
- wake_up_interruptible(&priv->delta_msr_wait);
+ wake_up_interruptible(&port->delta_msr_wait);
}
exit:
@@ -517,11 +515,14 @@
spin_unlock_irqrestore(&priv->lock, flags);
while (!multi_change) {
- 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;
+
spin_lock_irqsave(&priv->lock, flags);
status = priv->line_status;
multi_change = priv->multi_status_change;