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Commit 308a96c8 authored by Johan Hovold's avatar Johan Hovold Committed by Greg Kroah-Hartman
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USB: serial: mos7840: fix another NULL-deref at open 



commit 5182c2cf2a9bfb7f066ef0bdd2bb6330b94dd74e upstream.

Fix another NULL-pointer dereference at open should a malicious device
lack an interrupt-in endpoint.

Note that the driver has a broken check for an interrupt-in endpoint
which means that an interrupt URB has never even been submitted.

Fixes: 3f542974 ("USB: Moschip 7840 USB-Serial Driver")
Reviewed-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: default avatarJohan Hovold <johan@kernel.org>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent 9ab870e7

drivers/usb/serial/mos7840.c

+3 −1
Original line number Diff line number Diff line
@@ -1024,6 +1024,7 @@ static int mos7840_open(struct tty_struct *tty, struct usb_serial_port *port) 
	 * (can't set it up in mos7840_startup as the structures *

	 * were not set up at that time.)                        */

	if (port0->open_ports == 1) {

		/* FIXME: Buffer never NULL, so URB is not submitted. */

		if (serial->port[0]->interrupt_in_buffer == NULL) {

			/* set up interrupt urb */

			usb_fill_int_urb(serial->port[0]->interrupt_in_urb,
@@ -2119,7 +2120,8 @@ static int mos7840_calc_num_ports(struct usb_serial *serial) 
static int mos7840_attach(struct usb_serial *serial)

{

	if (serial->num_bulk_in < serial->num_ports ||

			serial->num_bulk_out < serial->num_ports) {

			serial->num_bulk_out < serial->num_ports ||

			serial->num_interrupt_in < 1) {

		dev_err(&serial->interface->dev, "missing endpoints\n");

		return -ENODEV;

	}