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[3.5.y.z,extended,stable] Patch "USB: quatech2: fix use-after-free in TIOCMIWAIT" has been added to staging queue

Message ID 1364234591-9991-1-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: quatech2: 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 56274ec22b39bdfde99da5edc0eb3aaec510f488 Mon Sep 17 00:00:00 2001
From: Johan Hovold <jhovold@gmail.com>
Date: Tue, 19 Mar 2013 09:21:23 +0100
Subject: [PATCH] USB: quatech2: fix use-after-free in TIOCMIWAIT

commit 69f87f40d2b98e8b4ab82a121fd2bd584690b887 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: backported to 3.5; adjust context ]
Luis Henriques <luis.henriques@canonical.com>
---
 drivers/usb/serial/quatech2.c | 12 +++++++-----
 1 file changed, 7 insertions(+), 5 deletions(-)

--
1.8.1.2
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Patch

diff --git a/drivers/usb/serial/quatech2.c b/drivers/usb/serial/quatech2.c
index e1065f8..1c2c0ba 100644
--- a/drivers/usb/serial/quatech2.c
+++ b/drivers/usb/serial/quatech2.c
@@ -132,7 +132,6 @@  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;
@@ -528,8 +527,9 @@  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)));
@@ -537,6 +537,9 @@  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);
@@ -881,7 +884,6 @@  static int qt2_attach(struct usb_serial *serial)

 		spin_lock_init(&port_priv->lock);
 		spin_lock_init(&port_priv->urb_lock);
-		init_waitqueue_head(&port_priv->delta_msr_wait);

 		port_priv->port = serial->port[pcount];

@@ -1015,7 +1017,7 @@  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);
 	}
 }