usb: kbd: destroy device after console is stopped

In case of IOMUX enabled it assumes that console devices in the list
are available to get them stopped properly via ->stop() callback.
However, the USB keyboard driver violates this assumption and tries
to play tricks so the device get destroyed while being listed as
an active console.

Swap the order of device deregistration and IOMUX update along with
converting to use iomux_replace_device() jelper to avoid the use-after-free.

Fixes: 3cbcb2892809 ("usb: Fix usb_kbd_deregister when console-muxing is used")
Fixes: 8a8348703081 ("dm: usb: Add a remove() method for USB keyboards")
Reported-by: Nicolas Saenz Julienne <nsaenzjulienne@suse.de>
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>

diff --git a/common/usb_kbd.c b/common/usb_kbd.c
index b316807..60c6027 100644 (file)
--- a/common/usb_kbd.c
+++ b/common/usb_kbd.c
@@ -617,12 +617,12 @@ int usb_kbd_deregister(int force)
        if (dev) {
                usb_kbd_dev = (struct usb_device *)dev->priv;
                data = usb_kbd_dev->privptr;
-               if (stdio_deregister_dev(dev, force) != 0)
-                       return 1;
 #if CONFIG_IS_ENABLED(CONSOLE_MUX)
-               if (iomux_doenv(stdin, env_get("stdin")) != 0)
+               if (iomux_replace_device(stdin, DEVNAME, force ? "nulldev" : ""))
                        return 1;
 #endif
+               if (stdio_deregister_dev(dev, force) != 0)
+                       return 1;
 #ifdef CONFIG_SYS_USB_EVENT_POLL_VIA_INT_QUEUE
                destroy_int_queue(usb_kbd_dev, data->intq);
 #endif
@@ -660,16 +660,16 @@ static int usb_kbd_remove(struct udevice *dev)
                goto err;
        }
        data = udev->privptr;
-       if (stdio_deregister_dev(sdev, true)) {
-               ret = -EPERM;
-               goto err;
-       }
 #if CONFIG_IS_ENABLED(CONSOLE_MUX)
-       if (iomux_doenv(stdin, env_get("stdin"))) {
+       if (iomux_replace_device(stdin, DEVNAME, "nulldev")) {
                ret = -ENOLINK;
                goto err;
        }
 #endif
+       if (stdio_deregister_dev(sdev, true)) {
+               ret = -EPERM;
+               goto err;
+       }
 #ifdef CONFIG_SYS_USB_EVENT_POLL_VIA_INT_QUEUE
        destroy_int_queue(udev, data->intq);
 #endif