HID: holtek: test for sanity of intfdata

The ioctl handler uses the intfdata of a second interface,
which may not be present in a broken or malicious device, hence
the intfdata needs to be checked for NULL.

[jkosina@suse.cz: fix newly added spurious space]
Reported-by: syzbot+965152643a75a56737be@syzkaller.appspotmail.com
Signed-off-by: Oliver Neukum <oneukum@suse.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>

diff --git a/drivers/hid/hid-holtek-kbd.c b/drivers/hid/hid-holtek-kbd.c
index b3d5024..0a38e8e 100644 (file)
--- a/drivers/hid/hid-holtek-kbd.c
+++ b/drivers/hid/hid-holtek-kbd.c
@@ -123,9 +123,14 @@ static int holtek_kbd_input_event(struct input_dev *dev, unsigned int type,
 
        /* Locate the boot interface, to receive the LED change events */
        struct usb_interface *boot_interface = usb_ifnum_to_if(usb_dev, 0);
+       struct hid_device *boot_hid;
+       struct hid_input *boot_hid_input;
 
-       struct hid_device *boot_hid = usb_get_intfdata(boot_interface);
-       struct hid_input *boot_hid_input = list_first_entry(&boot_hid->inputs,
+       if (unlikely(boot_interface == NULL))
+               return -ENODEV;
+
+       boot_hid = usb_get_intfdata(boot_interface);
+       boot_hid_input = list_first_entry(&boot_hid->inputs,
                struct hid_input, list);
 
        return boot_hid_input->input->event(boot_hid_input->input, type, code,