selinux: Fix missing calls to netlbl_skbuff_err()

At some point I think I messed up and dropped the calls to netlbl_skbuff_err()
which are necessary for CIPSO to send error notifications to remote systems.
This patch re-introduces the error handling calls into the SELinux code.

Signed-off-by: Paul Moore <paul.moore@hp.com>
Acked-by: James Morris <jmorris@namei.org>
diff --git a/security/selinux/hooks.c b/security/selinux/hooks.c
index b520667..a91146a 100644
--- a/security/selinux/hooks.c
+++ b/security/selinux/hooks.c
@@ -4101,6 +4101,8 @@
 			return err;
 		err = avc_has_perm(sk_sid, peer_sid,
 				   SECCLASS_PEER, PEER__RECV, &ad);
+		if (err)
+			selinux_netlbl_err(skb, err, 0);
 	} else {
 		err = selinux_netlbl_sock_rcv_skb(sksec, skb, family, &ad);
 		if (err)
@@ -4156,10 +4158,14 @@
 			return err;
 		err = selinux_inet_sys_rcv_skb(skb->iif, addrp, family,
 					       peer_sid, &ad);
-		if (err)
+		if (err) {
+			selinux_netlbl_err(skb, err, 0);
 			return err;
+		}
 		err = avc_has_perm(sk_sid, peer_sid, SECCLASS_PEER,
 				   PEER__RECV, &ad);
+		if (err)
+			selinux_netlbl_err(skb, err, 0);
 	}
 
 	if (secmark_active) {
@@ -4396,6 +4402,7 @@
 static unsigned int selinux_ip_forward(struct sk_buff *skb, int ifindex,
 				       u16 family)
 {
+	int err;
 	char *addrp;
 	u32 peer_sid;
 	struct avc_audit_data ad;
@@ -4419,10 +4426,14 @@
 	if (selinux_parse_skb(skb, &ad, &addrp, 1, NULL) != 0)
 		return NF_DROP;
 
-	if (peerlbl_active)
-		if (selinux_inet_sys_rcv_skb(ifindex, addrp, family,
-					     peer_sid, &ad) != 0)
+	if (peerlbl_active) {
+		err = selinux_inet_sys_rcv_skb(ifindex, addrp, family,
+					       peer_sid, &ad);
+		if (err) {
+			selinux_netlbl_err(skb, err, 1);
 			return NF_DROP;
+		}
+	}
 
 	if (secmark_active)
 		if (avc_has_perm(peer_sid, skb->secmark,