[PATCH 3.16 173/370] USB: serial: spcp8x5: fix NULL-deref at open

Ben Hutchings
2017-03-10T13:59:26Z

From: Johan Hovold <johan@kernel.org>

commit cc0909248258f679c4bb4cd315565d40abaf6bc6 upstream.

Fix NULL-pointer dereference in open() should the device lack the
expected endpoints:

Unable to handle kernel NULL pointer dereference at virtual address 00000030
...
PC is at spcp8x5_open+0x30/0xd0 [spcp8x5]

Fixes: 619a6f1d1423 ("USB: add usb-serial spcp8x5 driver")
Signed-off-by: Johan Hovold <johan@kernel.org>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
---
drivers/usb/serial/spcp8x5.c | 14 ++++++++++++++
1 file changed, 14 insertions(+)

--- a/drivers/usb/serial/spcp8x5.c
+++ b/drivers/usb/serial/spcp8x5.c
@@ -154,6 +154,19 @@ static int spcp8x5_probe(struct usb_seri
return 0;
}

+static int spcp8x5_attach(struct usb_serial *serial)
+{
+ unsigned char num_ports = serial->num_ports;
+
+ if (serial->num_bulk_in < num_ports ||
+ serial->num_bulk_out < num_ports) {
+ dev_err(&serial->interface->dev, "missing endpoints\n");
+ return -ENODEV;
+ }
+
+ return 0;
+}
+
static int spcp8x5_port_probe(struct usb_serial_port *port)
{
const struct usb_device_id *id = usb_get_serial_data(port->serial);
@@ -477,6 +490,7 @@ static struct usb_serial_driver spcp8x5_
.tiocmget = spcp8x5_tiocmget,
.tiocmset = spcp8x5_tiocmset,
.probe = spcp8x5_probe,
+ .attach = spcp8x5_attach,
.port_probe = spcp8x5_port_probe,
.port_remove = spcp8x5_port_remove,
};