userns: Teach security_path_chown to take kuids and kgids

Don't make the security modules deal with raw user space uid and
gids instead pass in a kuid_t and a kgid_t so that security modules
only have to deal with internal kernel uids and gids.

Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: James Morris <james.l.morris@oracle.com>
Cc: John Johansen <john.johansen@canonical.com>
Cc: Kentaro Takeda <takedakn@nttdata.co.jp>
Cc: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Acked-by: Serge Hallyn <serge.hallyn@canonical.com>
Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
diff --git a/fs/open.c b/fs/open.c
index f3d96e7..2b25739 100644
--- a/fs/open.c
+++ b/fs/open.c
@@ -534,7 +534,7 @@
 		newattrs.ia_valid |=
 			ATTR_KILL_SUID | ATTR_KILL_SGID | ATTR_KILL_PRIV;
 	mutex_lock(&inode->i_mutex);
-	error = security_path_chown(path, user, group);
+	error = security_path_chown(path, uid, gid);
 	if (!error)
 		error = notify_change(path->dentry, &newattrs);
 	mutex_unlock(&inode->i_mutex);