patch "USB: serial: io_ti: fix another NULL-deref at open" added to usb-linus

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 my usb git tree which can be found at
git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb.git
in the usb-linus branch.

The patch will show up in the next release of the linux-next tree (usually sometime within the next 24 hours during the week.)

The patch will hopefully also be merged in Linus's tree for the next -rc kernel release.

If you have any questions about this process, please let me know.

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

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(-)

index bf8a4f432f4b..3b1cfba0ec84 100644
@@ -1508,7 +1508,7 @@ static int do_boot_mode(struct edgeport_serial *serial,
 	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)

@@ -2560,14 +2560,18 @@ static int edge_startup(struct usb_serial *serial)
 
 	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);
 

@@ -2579,7 +2583,6 @@ static int edge_startup(struct usb_serial *serial)
 		}
 	}
 
-	INIT_DELAYED_WORK(&edge_serial->heartbeat_work, edge_heartbeat_work);
 	edge_heartbeat_schedule(edge_serial);
 
 	return 0;

2.11.0