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[3.5.y.z,extended,stable] Patch "USB: io_edgeport: fix use-after-free in TIOCMIWAIT" has been added to staging queue

Message ID 1364234581-9746-1-git-send-email-luis.henriques@canonical.com
State New
Headers show

Commit Message

Luis Henriques March 25, 2013, 6:03 p.m. UTC
This is a note to let you know that I have just added a patch titled

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

to the linux-3.5.y-queue branch of the 3.5.y.z extended stable tree 
which can be found at:

 http://kernel.ubuntu.com/git?p=ubuntu/linux.git;a=shortlog;h=refs/heads/linux-3.5.y-queue

If you, or anyone else, feels it should not be added to this tree, please 
reply to this email.

For more information about the 3.5.y.z tree, see
https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable

Thanks.
-Luis

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From 0f28bc4438adea9af11dbb3781b37e69525023d9 Mon Sep 17 00:00:00 2001
From: Johan Hovold <jhovold@gmail.com>
Date: Tue, 19 Mar 2013 09:21:16 +0100
Subject: [PATCH] USB: io_edgeport: fix use-after-free in TIOCMIWAIT

commit 333576255d4cfc53efd056aad438568184b36af6 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: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Luis Henriques <luis.henriques@canonical.com>
---
 drivers/usb/serial/io_edgeport.c | 12 +++++++-----
 1 file changed, 7 insertions(+), 5 deletions(-)

--
1.8.1.2
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Patch

diff --git a/drivers/usb/serial/io_edgeport.c b/drivers/usb/serial/io_edgeport.c
index e1f5ccd..457743a 100644
--- a/drivers/usb/serial/io_edgeport.c
+++ b/drivers/usb/serial/io_edgeport.c
@@ -114,7 +114,6 @@  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 */
@@ -1701,13 +1699,17 @@  static int edge_ioctl(struct tty_struct *tty,
 		dbg("%s (%d) TIOCMIWAIT", __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)
@@ -2088,7 +2090,7 @@  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 */