[PATCH 3.16 161/370] USB: serial: keyspan_pda: verify endpoints at probe

Ben Hutchings
2017-03-10T13:55:06Z

From: Johan Hovold <johan@kernel.org>

commit 5d9b0f859babe96175cd33d7162a9463a875ffde upstream.

Check for the expected endpoints in attach() and fail loudly if not
present.

Note that failing to do this appears to be benign since da280e348866
("USB: keyspan_pda: clean up write-urb busy handling") which prevents a
NULL-pointer dereference in write() by never marking a non-existent
write-urb as free.

Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2")
Signed-off-by: Johan Hovold <johan@kernel.org>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
---
drivers/usb/serial/keyspan_pda.c | 14 ++++++++++++++
1 file changed, 14 insertions(+)

--- a/drivers/usb/serial/keyspan_pda.c
+++ b/drivers/usb/serial/keyspan_pda.c
@@ -699,6 +699,19 @@ MODULE_FIRMWARE("keyspan_pda/keyspan_pda
MODULE_FIRMWARE("keyspan_pda/xircom_pgs.fw");
#endif

+static int keyspan_pda_attach(struct usb_serial *serial)
+{
+ unsigned char num_ports = serial->num_ports;
+
+ if (serial->num_bulk_out < num_ports ||
+ serial->num_interrupt_in < num_ports) {
+ dev_err(&serial->interface->dev, "missing endpoints\n");
+ return -ENODEV;
+ }
+
+ return 0;
+}
+
static int keyspan_pda_port_probe(struct usb_serial_port *port)
{

@@ -776,6 +789,7 @@ static struct usb_serial_driver keyspan_
.break_ctl = keyspan_pda_break_ctl,
.tiocmget = keyspan_pda_tiocmget,
.tiocmset = keyspan_pda_tiocmset,
+ .attach = keyspan_pda_attach,
.port_probe = keyspan_pda_port_probe,
.port_remove = keyspan_pda_port_remove,
};