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USB: serial: mos7840: fix another NULL-deref at open

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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: 3f5429746d91 ("USB: Moschip 7840 USB-Serial Driver")
Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Johan Hovold <johan@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Johan Hovold 2017-02-09 12:11:41 +01:00 committed by Greg Kroah-Hartman
parent 04fae8abfa
commit 1ae570ab1c
1 changed files with 3 additions and 1 deletions

4
drivers/usb/serial/mos7840.c

@ -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;
}