patch "USB: io_edgeport: fix use-after-free in TIOCMIWAIT" added to usb tree

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This is a note to let you know that I've just added the patch titled

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

to my usb git tree which can be found at
    git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb.git
in the usb-linus branch.

The patch will show up in the next release of the linux-next tree
(usually sometime within the next 24 hours during the week.)

The patch will hopefully also be merged in Linus's tree for the
next -rc kernel release.

If you have any questions about this process, please let me know.


>From 333576255d4cfc53efd056aad438568184b36af6 Mon Sep 17 00:00:00 2001
From: Johan Hovold <jhovold@xxxxxxxxx>
Date: Tue, 19 Mar 2013 09:21:16 +0100
Subject: USB: io_edgeport: 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@xxxxxxxxxxxxxxx>
Signed-off-by: Johan Hovold <jhovold@xxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
 drivers/usb/serial/io_edgeport.c | 12 +++++++-----
 1 file changed, 7 insertions(+), 5 deletions(-)

diff --git a/drivers/usb/serial/io_edgeport.c b/drivers/usb/serial/io_edgeport.c
index b00e5cb..efd8b97 100644
--- a/drivers/usb/serial/io_edgeport.c
+++ b/drivers/usb/serial/io_edgeport.c
@@ -110,7 +110,6 @@ struct edgeport_port {
 	wait_queue_head_t	wait_chase;		/* for handling sleeping while waiting for chase to finish */
 	wait_queue_head_t	wait_open;		/* for handling sleeping while waiting for open to finish */
 	wait_queue_head_t	wait_command;		/* for handling sleeping while waiting for command to finish */
-	wait_queue_head_t	delta_msr_wait;		/* for handling sleeping while waiting for msr change to happen */
 
 	struct async_icount	icount;
 	struct usb_serial_port	*port;			/* loop back to the owner of this object */
@@ -884,7 +883,6 @@ static int edge_open(struct tty_struct *tty, struct usb_serial_port *port)
 	/* initialize our wait queues */
 	init_waitqueue_head(&edge_port->wait_open);
 	init_waitqueue_head(&edge_port->wait_chase);
-	init_waitqueue_head(&edge_port->delta_msr_wait);
 	init_waitqueue_head(&edge_port->wait_command);
 
 	/* initialize our icount structure */
@@ -1669,13 +1667,17 @@ static int edge_ioctl(struct tty_struct *tty,
 		dev_dbg(&port->dev, "%s (%d) TIOCMIWAIT\n", __func__,  port->number);
 		cprev = edge_port->icount;
 		while (1) {
-			prepare_to_wait(&edge_port->delta_msr_wait,
+			prepare_to_wait(&port->delta_msr_wait,
 						&wait, TASK_INTERRUPTIBLE);
 			schedule();
-			finish_wait(&edge_port->delta_msr_wait, &wait);
+			finish_wait(&port->delta_msr_wait, &wait);
 			/* see if a signal did it */
 			if (signal_pending(current))
 				return -ERESTARTSYS;
+
+			if (port->serial->disconnected)
+				return -EIO;
+
 			cnow = edge_port->icount;
 			if (cnow.rng == cprev.rng && cnow.dsr == cprev.dsr &&
 			    cnow.dcd == cprev.dcd && cnow.cts == cprev.cts)
@@ -2051,7 +2053,7 @@ static void handle_new_msr(struct edgeport_port *edge_port, __u8 newMsr)
 			icount->dcd++;
 		if (newMsr & EDGEPORT_MSR_DELTA_RI)
 			icount->rng++;
-		wake_up_interruptible(&edge_port->delta_msr_wait);
+		wake_up_interruptible(&edge_port->port->delta_msr_wait);
 	}
 
 	/* Save the new modem status */
-- 
1.8.0.rc0.18.gf84667d


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