BugLink: https://bugs.launchpad.net/bugs/1845038

commit 01ec0a5f upstream.

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>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Connor Kuehl <connor.kuehl@canonical.com>
Signed-off-by: Khalid Elmously <khalid.elmously@canonical.com>