sctp: label accepted/peeled off sockets

Accepted or peeled off sockets were missing a security label (e.g.
SELinux) which means that socket was in "unlabeled" state.

This patch clones the sock's label from the parent sock and resolves the
issue (similar to AF_BLUETOOTH protocol family).

Cc: Paul Moore <pmoore@redhat.com>
Cc: David Teigland <teigland@redhat.com>
Signed-off-by: Marcelo Ricardo Leitner <marcelo.leitner@gmail.com>
Acked-by: Paul Moore <paul@paul-moore.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/sctp/socket.c

@@ -7202,6 +7202,8 @@ void sctp_copy_sock(struct sock *newsk, struct sock *sk,
 
 	if (newsk->sk_flags & SK_FLAGS_TIMESTAMP)
 		net_enable_timestamp();
+
+	security_sk_clone(sk, newsk);
 }
 
 static inline void sctp_copy_descendant(struct sock *sk_to,