selinux: Support for the new TUN LSM hooks

Add support for the new TUN LSM hooks: security_tun_dev_create(),
security_tun_dev_post_create() and security_tun_dev_attach().  This includes
the addition of a new object class, tun_socket, which represents the socks
associated with TUN devices.  The _tun_dev_create() and _tun_dev_post_create()
hooks are fairly similar to the standard socket functions but _tun_dev_attach()
is a bit special.  The _tun_dev_attach() is unique because it involves a
domain attaching to an existing TUN device and its associated tun_socket
object, an operation which does not exist with standard sockets and most
closely resembles a relabel operation.

Signed-off-by: Paul Moore <paul.moore@hp.com>
Acked-by: Eric Paris <eparis@parisplace.org>
Signed-off-by: James Morris <jmorris@namei.org>
diff --git a/security/selinux/include/av_inherit.h b/security/selinux/include/av_inherit.h
index 8377a4b..abedcd7 100644
--- a/security/selinux/include/av_inherit.h
+++ b/security/selinux/include/av_inherit.h
@@ -15,6 +15,7 @@
    S_(SECCLASS_KEY_SOCKET, socket, 0x00400000UL)
    S_(SECCLASS_UNIX_STREAM_SOCKET, socket, 0x00400000UL)
    S_(SECCLASS_UNIX_DGRAM_SOCKET, socket, 0x00400000UL)
+   S_(SECCLASS_TUN_SOCKET, socket, 0x00400000UL)
    S_(SECCLASS_IPC, ipc, 0x00000200UL)
    S_(SECCLASS_SEM, ipc, 0x00000200UL)
    S_(SECCLASS_MSGQ, ipc, 0x00000200UL)