[4.2.y-ckt stable] Patch "USB: serial: keyspan: 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: keyspan: 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 ad115b28f182106ec70af922f0d1f4416731a9ab Mon Sep 17 00:00:00 2001
From: Johan Hovold <johan at kernel.org>
Date: Sun, 8 May 2016 20:07:58 +0200
Subject: USB: serial: keyspan: fix use-after-free in probe error path

commit 35be1a71d70775e7bd7e45fa6d2897342ff4c9d2 upstream.

The interface instat and indat URBs were submitted in attach, but never
unlinked in release before deallocating the corresponding transfer
buffers.

In the case of a late probe error (e.g. due to failed minor allocation),
disconnect would not have been called before release, causing the
buffers to be freed while the URBs are still in use. We'd also end up
with active URBs for an unbound interface.

Fixes: f9c99bb8b3a1 ("USB: usb-serial: replace shutdown with disconnect,
release")
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/keyspan.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/drivers/usb/serial/keyspan.c b/drivers/usb/serial/keyspan.c
index e07b15e..7faa901 100644
--- a/drivers/usb/serial/keyspan.c
+++ b/drivers/usb/serial/keyspan.c
@@ -2376,6 +2376,10 @@ static void keyspan_release(struct usb_serial *serial)

 	s_priv = usb_get_serial_data(serial);

+	/* Make sure to unlink the URBs submitted in attach. */
+	usb_kill_urb(s_priv->instat_urb);
+	usb_kill_urb(s_priv->indat_urb);
+
 	usb_free_urb(s_priv->instat_urb);
 	usb_free_urb(s_priv->indat_urb);
 	usb_free_urb(s_priv->glocont_urb);
--
2.7.4