Patch "USB: serial: io_ti: fix another NULL-deref at open" has been added to the 4.4-stable tree

This is a note to let you know that I've just added the patch titled

USB: serial: io_ti: fix another NULL-deref at open

to the 4.4-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
usb-serial-io_ti-fix-another-null-deref-at-open.patch
and it can be found in the queue-4.4 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree, please let <[email protected]> know about it.

From: Johan Hovold <[email protected]>
Date: Tue, 3 Jan 2017 16:39:44 +0100
Subject: USB: serial: io_ti: fix another NULL-deref at open

From: Johan Hovold <[email protected]>

commit 4f9785cc99feeb3673993b471f646b4dbaec2cc1 upstream.

In case a device is left in "boot-mode" we must not register any port devices in order to avoid a NULL-pointer dereference on open due to missing endpoints. This could be used by a malicious device to trigger an OOPS:

Unable to handle kernel NULL pointer dereference at virtual address 00000030

...
[<bf0caa84>] (edge_open [io_ti]) from [<bf0b0118>] (serial_port_activate+0x68/0x98 [usbserial]) [<bf0b0118>] (serial_port_activate [usbserial]) from [<c0470ca4>] (tty_port_open+0x9c/0xe8) [<c0470ca4>] (tty_port_open) from [<bf0b0da0>] (serial_open+0x48/0x6c [usbserial]) [<bf0b0da0>] (serial_open [usbserial]) from [<c0469178>] (tty_open+0xcc/0x5cc)

---
 drivers/usb/serial/io_ti.c |    9 ++++++---
 1 file changed, 6 insertions(+), 3 deletions(-)

@@ -1508,7 +1508,7 @@ stayinbootmode:
 	dev_dbg(dev, "%s - STAYING IN BOOT MODE\n", __func__);
 	serial->product_info.TiMode = TI_MODE_BOOT;
 
-	return 0;
+	return 1;
 }
 
 static int ti_do_config(struct edgeport_port *port, int feature, int on)

@@ -2563,14 +2563,18 @@ static int edge_startup(struct usb_seria
 
 	mutex_init(&edge_serial->es_lock);
 	edge_serial->serial = serial;
+	INIT_DELAYED_WORK(&edge_serial->heartbeat_work, edge_heartbeat_work);
 	usb_set_serial_data(serial, edge_serial);
 
 	status = download_fw(edge_serial);
-	if (status) {
+	if (status < 0) {
 		kfree(edge_serial);
 		return status;
 	}
 
+	if (status > 0)
+		return 1;	/* bind but do not register any ports */
+
 	product_id = le16_to_cpu(
 			edge_serial->serial->dev->descriptor.idProduct);
 

@@ -2582,7 +2586,6 @@ static int edge_startup(struct usb_seria
 		}
 	}
 
-	INIT_DELAYED_WORK(&edge_serial->heartbeat_work, edge_heartbeat_work);
 	edge_heartbeat_schedule(edge_serial);
 
 	return 0;

Patches currently in stable-queue which might be from [email protected] are

queue-4.4/usb-serial-io_ti-fix-i-o-after-disconnect.patch queue-4.4/usb-serial-ti_usb_3410_5052-fix-null-deref-at-open.patch queue-4.4/usb-serial-kobil_sct-fix-null-deref-in-write.patch queue-4.4/usb-serial-spcp8x5-fix-null-deref-at-open.patch queue-4.4/usb-serial-mos7720-fix-parallel-probe.patch queue-4.4/usb-serial-cyberjack-fix-null-deref-at-open.patch queue-4.4/usb-serial-mos7720-fix-null-deref-at-open.patch queue-4.4/usb-serial-garmin_gps-fix-memory-leak-on-failed-urb-submit.patch queue-4.4/usb-serial-io_ti-fix-null-deref-at-open.patch queue-4.4/usb-serial-pl2303-fix-null-deref-at-open.patch queue-4.4/usb-serial-quatech2-fix-sleep-while-atomic-in-close.patch queue-4.4/usb-serial-iuu_phoenix-fix-null-deref-at-open.patch queue-4.4/usb-serial-oti6858-fix-null-deref-at-open.patch queue-4.4/usb-serial-io_edgeport-fix-null-deref-at-open.patch queue-4.4/usb-serial-mos7720-fix-parport-use-after-free-on-probe-errors.patch queue-4.4/usb-serial-mos7720-fix-use-after-free-on-probe-errors.patch queue-4.4/usb-serial-mos7840-fix-null-deref-at-open.patch queue-4.4/usb-serial-omninet-fix-null-derefs-at-open-and-disconnect.patch queue-4.4/usb-serial-keyspan_pda-verify-endpoints-at-probe.patch queue-4.4/usb-serial-io_ti-fix-another-null-deref-at-open.patch