From 69f87f40d2b98e8b4ab82a121fd2bd584690b887 Mon Sep 17 00:00:00 2001 From: Johan Hovold Date: Tue, 19 Mar 2013 09:21:23 +0100 Subject: [PATCH] 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 Signed-off-by: Johan Hovold Signed-off-by: Greg Kroah-Hartman --- drivers/usb/serial/quatech2.c | 12 +++++++----- 1 file changed, 7 insertions(+), 5 deletions(-) diff --git a/drivers/usb/serial/quatech2.c b/drivers/usb/serial/quatech2.c index d643a4d4d770..75f125ddb0c9 100644 --- a/drivers/usb/serial/quatech2.c +++ b/drivers/usb/serial/quatech2.c @@ -128,7 +128,6 @@ struct qt2_port_private { 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 @@ static int wait_modem_info(struct usb_serial_port *port, unsigned int arg) 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 @@ static int wait_modem_info(struct usb_serial_port *port, unsigned int arg) 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 @@ static int qt2_port_probe(struct usb_serial_port *port) 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 @@ static void qt2_update_msr(struct usb_serial_port *port, unsigned char *ch) if (newMSR & UART_MSR_TERI) port_priv->icount.rng++; - wake_up_interruptible(&port_priv->delta_msr_wait); + wake_up_interruptible(&port->delta_msr_wait); } }