[4.2.y-ckt stable] Patch "USB: serial: quatech2: fix use-after-free in probe error path" has been added to the 4.2.y-ckt tree

[Kamal Mostafa]

This is a note to let you know that I have just added a patch titled

    USB: serial: quatech2: fix use-after-free in probe error path

to the linux-4.2.y-queue branch of the 4.2.y-ckt extended stable tree 
which can be found at:

    https://git.launchpad.net/~canonical-kernel/linux/+git/linux-stable-ckt/log/?h=linux-4.2.y-queue

This patch is scheduled to be released in version 4.2.8-ckt12.

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

For more information about the 4.2.y-ckt tree, see
https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable

Thanks.
-Kamal

---8<------------------------------------------------------------

>From 9f266c8ec0aca83e1ba7c329b6a70c872aa2769a Mon Sep 17 00:00:00 2001
From: Johan Hovold <johan at kernel.org>
Date: Sun, 8 May 2016 20:08:02 +0200
Subject: USB: serial: quatech2: fix use-after-free in probe error path

commit 028c49f5e02a257c94129cd815f7c8485f51d4ef upstream.

The interface read URB is submitted in attach, but was only unlinked by
the driver at disconnect.

In case of a late probe error (e.g. due to failed minor allocation),
disconnect is never called and we would end up with active URBs for an
unbound interface. This in turn could lead to deallocated memory being
dereferenced in the completion callback.

Fixes: f7a33e608d9a ("USB: serial: add quatech2 usb to serial driver")
Signed-off-by: Johan Hovold <johan at kernel.org>
Acked-by: Greg Kroah-Hartman <gregkh at linuxfoundation.org>
Signed-off-by: Kamal Mostafa <kamal at canonical.com>
---
 drivers/usb/serial/quatech2.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/drivers/usb/serial/quatech2.c b/drivers/usb/serial/quatech2.c
index 504f5bf..b18974c 100644
--- a/drivers/usb/serial/quatech2.c
+++ b/drivers/usb/serial/quatech2.c
@@ -141,6 +141,7 @@ static void qt2_release(struct usb_serial *serial)

 	serial_priv = usb_get_serial_data(serial);

+	usb_kill_urb(serial_priv->read_urb);
 	usb_free_urb(serial_priv->read_urb);
 	kfree(serial_priv->read_buffer);
 	kfree(serial_priv);
--
2.7.4