[3.11.y.z extended stable] Patch "USB: ftdi_sio: fix null deref at port probe" has been added to staging queue

[Luis Henriques]

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

    USB: ftdi_sio: fix null deref at port probe

to the linux-3.11.y-queue branch of the 3.11.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-3.11.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 3.11.y.z tree, see
https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable

Thanks.
-Luis

------

>From fbba9eb1b549d6087a7e6c40e104ba3a4fe383ea Mon Sep 17 00:00:00 2001
From: Johan Hovold <johan at kernel.org>
Date: Thu, 5 Jun 2014 16:05:52 +0200
Subject: USB: ftdi_sio: fix null deref at port probe

commit aea1ae8760314e072bf1b773521e9de5d5dda10d upstream.

Fix NULL-pointer dereference when probing an interface with no
endpoints.

These devices have two bulk endpoints per interface, but this avoids
crashing the kernel if a user forces a non-FTDI device to be probed.

Note that the iterator variable was made unsigned in order to avoid
a maybe-uninitialized compiler warning for ep_desc after the loop.

Fixes: 895f28badce9 ("USB: ftdi_sio: fix hi-speed device packet size
calculation")

Reported-by: Mike Remski <mremski at mutualink.net>
Tested-by: Mike Remski <mremski at mutualink.net>
Signed-off-by: Johan Hovold <johan at kernel.org>
Signed-off-by: Luis Henriques <luis.henriques at canonical.com>
---
 drivers/usb/serial/ftdi_sio.c | 7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)

diff --git a/drivers/usb/serial/ftdi_sio.c b/drivers/usb/serial/ftdi_sio.c
index b9e663ac9a35..3e315de9bbd4 100644
--- a/drivers/usb/serial/ftdi_sio.c
+++ b/drivers/usb/serial/ftdi_sio.c
@@ -1577,14 +1577,17 @@ static void ftdi_set_max_packet_size(struct usb_serial_port *port)
 	struct usb_device *udev = serial->dev;

 	struct usb_interface *interface = serial->interface;
-	struct usb_endpoint_descriptor *ep_desc = &interface->cur_altsetting->endpoint[1].desc;
+	struct usb_endpoint_descriptor *ep_desc;

 	unsigned num_endpoints;
-	int i;
+	unsigned i;

 	num_endpoints = interface->cur_altsetting->desc.bNumEndpoints;
 	dev_info(&udev->dev, "Number of endpoints %d\n", num_endpoints);

+	if (!num_endpoints)
+		return;
+
 	/* NOTE: some customers have programmed FT232R/FT245R devices
 	 * with an endpoint size of 0 - not good.  In this case, we
 	 * want to override the endpoint descriptor setting and use a
--
1.9.1