USB: ch341: fix use-after-free in TIOCMIWAIT
commit fa1e11d5231c001c80a479160b5832933c5d35fb 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: Ben Hutchings <ben@decadent.org.uk>
Cc: Yang Yingliang <yangyingliang@huawei.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 aaab32d..a45594a 100644
--- a/drivers/usb/serial/ch341.c
+++ b/drivers/usb/serial/ch341.c
@@ -82,7 +82,6 @@
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 */
@@ -262,7 +261,6 @@
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;
@@ -299,7 +297,7 @@
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)
@@ -502,7 +500,7 @@
tty_kref_put(tty);
}
- wake_up_interruptible(&priv->delta_msr_wait);
+ wake_up_interruptible(&port->delta_msr_wait);
}
exit:
@@ -528,11 +526,14 @@
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;