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>

include/net/netlabel.h

@@ -382,7 +382,7 @@ int netlbl_sock_getattr(struct sock *sk,
 int netlbl_skbuff_getattr(const struct sk_buff *skb,
 			  u16 family,
 			  struct netlbl_lsm_secattr *secattr);
-void netlbl_skbuff_err(struct sk_buff *skb, int error);
+void netlbl_skbuff_err(struct sk_buff *skb, int error, int gateway);
 
 /*
  * LSM label mapping cache operations
@@ -454,7 +454,9 @@ static inline int netlbl_skbuff_getattr(const struct sk_buff *skb,
 {
 	return -ENOSYS;
 }
-static inline void netlbl_skbuff_err(struct sk_buff *skb, int error)
+static inline void netlbl_skbuff_err(struct sk_buff *skb,
+				     int error,
+				     int gateway)
 {
 	return;
 }

net/netlabel/netlabel_kapi.c

@@ -490,6 +490,7 @@ int netlbl_skbuff_getattr(const struct sk_buff *skb,
  * netlbl_skbuff_err - Handle a LSM error on a sk_buff
  * @skb: the packet
  * @error: the error code
+ * @gateway: true if host is acting as a gateway, false otherwise
  *
  * Description:
  * Deal with a LSM problem when handling the packet in @skb, typically this is
@@ -497,10 +498,10 @@ int netlbl_skbuff_getattr(const struct sk_buff *skb,
  * according to the packet's labeling protocol.
  *
  */
-void netlbl_skbuff_err(struct sk_buff *skb, int error)
+void netlbl_skbuff_err(struct sk_buff *skb, int error, int gateway)
 {
 	if (CIPSO_V4_OPTEXIST(skb))
-		cipso_v4_error(skb, error, 0);
+		cipso_v4_error(skb, error, gateway);
 }
 
 /**

security/selinux/hooks.c

@@ -4101,6 +4101,8 @@ static int selinux_sock_rcv_skb_compat(struct sock *sk, struct sk_buff *skb,
 			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 @@ static int selinux_socket_sock_rcv_skb(struct sock *sk, struct sk_buff *skb)
 			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 int selinux_nlmsg_perm(struct sock *sk, struct sk_buff *skb)
 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 @@ static unsigned int selinux_ip_forward(struct sk_buff *skb, int ifindex,
 	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,

security/selinux/include/netlabel.h

@@ -39,6 +39,8 @@
 #ifdef CONFIG_NETLABEL
 void selinux_netlbl_cache_invalidate(void);
 
+void selinux_netlbl_err(struct sk_buff *skb, int error, int gateway);
+
 void selinux_netlbl_sk_security_reset(struct sk_security_struct *ssec,
 				      int family);
 
@@ -63,6 +65,13 @@ static inline void selinux_netlbl_cache_invalidate(void)
 	return;
 }
 
+static inline void selinux_netlbl_err(struct sk_buff *skb,
+				      int error,
+				      int gateway)
+{
+	return;
+}
+
 static inline void selinux_netlbl_sk_security_reset(
 					       struct sk_security_struct *ssec,
 					       int family)

security/selinux/netlabel.c

@@ -107,6 +107,24 @@ void selinux_netlbl_cache_invalidate(void)
 	netlbl_cache_invalidate();
 }
 
+/**
+ * selinux_netlbl_err - Handle a NetLabel packet error
+ * @skb: the packet
+ * @error: the error code
+ * @gateway: true if host is acting as a gateway, false otherwise
+ *
+ * Description:
+ * When a packet is dropped due to a call to avc_has_perm() pass the error
+ * code to the NetLabel subsystem so any protocol specific processing can be
+ * done.  This is safe to call even if you are unsure if NetLabel labeling is
+ * present on the packet, NetLabel is smart enough to only act when it should.
+ *
+ */
+void selinux_netlbl_err(struct sk_buff *skb, int error, int gateway)
+{
+	netlbl_skbuff_err(skb, error, gateway);
+}
+
 /**
  * selinux_netlbl_sk_security_reset - Reset the NetLabel fields
  * @ssec: the sk_security_struct
@@ -289,7 +307,7 @@ int selinux_netlbl_sock_rcv_skb(struct sk_security_struct *sksec,
 		return 0;
 
 	if (nlbl_sid != SECINITSID_UNLABELED)
-		netlbl_skbuff_err(skb, rc);
+		netlbl_skbuff_err(skb, rc, 0);
 	return rc;
 }