Commit 91a1ff4d authored Jan 03, 2017 by Johan Hovold

USB: serial: mos7720: fix use-after-free on probe errors



The interrupt URB was submitted on probe but never stopped on probe
errors. This can lead to use-after-free issues in the completion
handler when accessing the freed usb-serial struct:

Unable to handle kernel paging request at virtual address 6b6b6be7
...
[<bf052e70>] (mos7715_interrupt_callback [mos7720]) from [<c052a894>] (__usb_hcd_giveback_urb+0x80/0x140)
[<c052a894>] (__usb_hcd_giveback_urb) from [<c052a9a4>] (usb_hcd_giveback_urb+0x50/0x138)
[<c052a9a4>] (usb_hcd_giveback_urb) from [<c0550684>] (musb_giveback+0xc8/0x1cc)

Fixes: b69578df ("USB: usbserial: mos7720: add support for parallel
port on moschip 7715")
Cc: stable <stable@vger.kernel.org>
Signed-off-by: Johan Hovold <johan@kernel.org>

parent b05aebc2

drivers/usb/serial/mos7720.c

+5 −1

Original line number	Diff line number	Diff line
		@@ -1962,9 +1962,11 @@ static int mos7720_startup(struct usb_serial *serial)
		#ifdef CONFIG_USB_SERIAL_MOS7715_PARPORT
		if (product == MOSCHIP_DEVICE_ID_7715) {
		ret_val = mos7715_parport_init(serial);
		if (ret_val < 0)
		if (ret_val < 0) {
		usb_kill_urb(serial->port[0]->interrupt_in_urb);
		return ret_val;
		}
		}
		#endif
		/* LSR For Port 1 */
		read_mos_reg(serial, 0, MOS7720_LSR, &data);
		@@ -1975,6 +1977,8 @@ static int mos7720_startup(struct usb_serial *serial)

		static void mos7720_release(struct usb_serial *serial)
		{
		usb_kill_urb(serial->port[0]->interrupt_in_urb);

		#ifdef CONFIG_USB_SERIAL_MOS7715_PARPORT
		/* close the parallel port */