[PATCH 3.16 165/370] USB: serial: mos7720: fix parport use-after-free on probe errors

Ben Hutchings
2017-03-10T12:17:51Z

From: Johan Hovold <johan@kernel.org>

commit 75dd211e773afcbc264677b0749d1cf7d937ab2d upstream.

Do not submit the interrupt URB until after the parport has been
successfully registered to avoid another use-after-free in the
completion handler when accessing the freed parport private data in case
of a racing completion.

Fixes: b69578df7e98 ("USB: usbserial: mos7720: add support for parallel
port on moschip 7715")
Signed-off-by: Johan Hovold <johan@kernel.org>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
---
drivers/usb/serial/mos7720.c | 18 ++++++++----------
1 file changed, 8 insertions(+), 10 deletions(-)

--- a/drivers/usb/serial/mos7720.c
+++ b/drivers/usb/serial/mos7720.c
@@ -1936,22 +1936,20 @@ static int mos7720_startup(struct usb_se
usb_control_msg(serial->dev, usb_sndctrlpipe(serial->dev, 0),
(__u8)0x03, 0x00, 0x01, 0x00, NULL, 0x00, 5000);

- /* start the interrupt urb */
- ret_val = usb_submit_urb(serial->port[0]->interrupt_in_urb, GFP_KERNEL);
- if (ret_val)
- dev_err(&dev->dev,
- "%s - Error %d submitting control urb\n",
- __func__, ret_val);
-
#ifdef CONFIG_USB_SERIAL_MOS7715_PARPORT
if (product == MOSCHIP_DEVICE_ID_7715) {
ret_val = mos7715_parport_init(serial);
- if (ret_val < 0) {
- usb_kill_urb(serial->port[0]->interrupt_in_urb);
+ if (ret_val < 0)
return ret_val;
- }
}
#endif
+ /* start the interrupt urb */
+ ret_val = usb_submit_urb(serial->port[0]->interrupt_in_urb, GFP_KERNEL);
+ if (ret_val) {
+ dev_err(&dev->dev, "failed to submit interrupt urb: %d\n",
+ ret_val);
+ }
+
/* LSR For Port 1 */
read_mos_reg(serial, 0, LSR, &data);
dev_dbg(&dev->dev, "LSR:%x\n", data);