[NetLabel]: correct improper handling of non-NetLabel peer contexts

Fix a problem where NetLabel would always set the value of 
sk_security_struct->peer_sid in selinux_netlbl_sock_graft() to the context of
the socket, causing problems when users would query the context of the
connection.  This patch fixes this so that the value in
sk_security_struct->peer_sid is only set when the connection is NetLabel based,
otherwise the value is untouched.

Signed-off-by: Paul Moore <paul.moore@hp.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/include/net/netlabel.h b/include/net/netlabel.h
index dd5780b..bf7b564 100644
--- a/include/net/netlabel.h
+++ b/include/net/netlabel.h
@@ -238,6 +238,8 @@
 #ifdef CONFIG_NETLABEL
 int netlbl_socket_setattr(const struct socket *sock,
 			  const struct netlbl_lsm_secattr *secattr);
+int netlbl_sock_getattr(struct sock *sk,
+			struct netlbl_lsm_secattr *secattr);
 int netlbl_socket_getattr(const struct socket *sock,
 			  struct netlbl_lsm_secattr *secattr);
 int netlbl_skbuff_getattr(const struct sk_buff *skb,
@@ -250,6 +252,12 @@
 	return -ENOSYS;
 }
 
+static inline int netlbl_sock_getattr(struct sock *sk,
+				      struct netlbl_lsm_secattr *secattr)
+{
+	return -ENOSYS;
+}
+
 static inline int netlbl_socket_getattr(const struct socket *sock,
 					struct netlbl_lsm_secattr *secattr)
 {