HID: hidraw: tighten ioctl command parsing

The handling for variable-length ioctl commands in hidraw_ioctl() is
rather complex and the check for the data direction is incomplete.

Simplify this code by factoring out the various ioctls grouped by dir
and size, and using a switch() statement with the size masked out, to
ensure the rest of the command is correctly matched.

Fixes: 9188e79ec3 ("HID: add phys and name ioctls to hidraw")
Reported-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Benjamin Tissoires <bentiss@kernel.org>
Signed-off-by: Jiri Kosina <jkosina@suse.com>

include/uapi/linux/hidraw.h

@@ -48,6 +48,8 @@ struct hidraw_devinfo {
 #define HIDIOCGOUTPUT(len)    _IOC(_IOC_WRITE|_IOC_READ, 'H', 0x0C, len)
 #define HIDIOCREVOKE	      _IOW('H', 0x0D, int) /* Revoke device access */
 
+#define HIDIOCTL_LAST		_IOC_NR(HIDIOCREVOKE)
+
 #define HIDRAW_FIRST_MINOR 0
 #define HIDRAW_MAX_DEVICES 64
 /* number of reports to buffer */