net: dsa: Discard frames from unused ports

commit fc5f33768c upstream.

The Marvell switches under some conditions will pass a frame to the
host with the port being the CPU port. Such frames are invalid, and
should be dropped. Not dropping them can result in a crash when
incrementing the receive statistics for an invalid port.

This has been reworked for 4.14, which does not have the central
dsa_master_find_slave() function, so each tag driver needs to check.

Reported-by: Chris Healy <cphealy@gmail.com>
Fixes: 91da11f870 ("net: Distributed Switch Architecture protocol support")
Signed-off-by: Andrew Lunn <andrew@lunn.ch>
Reviewed-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

net/dsa/tag_brcm.c

@@ -121,6 +121,9 @@ static struct sk_buff *brcm_tag_rcv(struct sk_buff *skb, struct net_device *dev,
 	if (source_port >= ds->num_ports || !ds->ports[source_port].netdev)
 		return NULL;
 
+	if (unlikely(ds->cpu_port_mask & BIT(source_port)))
+		return NULL;
+
 	/* Remove Broadcom tag and update checksum */
 	skb_pull_rcsum(skb, BRCM_TAG_LEN);
 

net/dsa/tag_dsa.c

@@ -107,6 +107,9 @@ static struct sk_buff *dsa_rcv(struct sk_buff *skb, struct net_device *dev,
 	if (source_port >= ds->num_ports || !ds->ports[source_port].netdev)
 		return NULL;
 
+	if (unlikely(ds->cpu_port_mask & BIT(source_port)))
+		return NULL;
+
 	/*
 	 * Convert the DSA header to an 802.1q header if the 'tagged'
 	 * bit in the DSA header is set.  If the 'tagged' bit is clear,

net/dsa/tag_edsa.c

@@ -120,6 +120,9 @@ static struct sk_buff *edsa_rcv(struct sk_buff *skb, struct net_device *dev,
 	if (source_port >= ds->num_ports || !ds->ports[source_port].netdev)
 		return NULL;
 
+	if (unlikely(ds->cpu_port_mask & BIT(source_port)))
+		return NULL;
+
 	/*
 	 * If the 'tagged' bit is set, convert the DSA tag to a 802.1q
 	 * tag and delete the ethertype part.  If the 'tagged' bit is

net/dsa/tag_ksz.c

@@ -92,6 +92,9 @@ static struct sk_buff *ksz_rcv(struct sk_buff *skb, struct net_device *dev,
 	if (source_port >= ds->num_ports || !ds->ports[source_port].netdev)
 		return NULL;
 
+	if (unlikely(ds->cpu_port_mask & BIT(source_port)))
+		return NULL;
+
 	pskb_trim_rcsum(skb, skb->len - KSZ_EGRESS_TAG_LEN);
 
 	skb->dev = ds->ports[source_port].netdev;

net/dsa/tag_lan9303.c

@@ -108,6 +108,9 @@ static struct sk_buff *lan9303_rcv(struct sk_buff *skb, struct net_device *dev,
 		return NULL;
 	}
 
+	if (unlikely(ds->cpu_port_mask & BIT(source_port)))
+		return NULL;
+
 	if (!ds->ports[source_port].netdev) {
 		dev_warn_ratelimited(&dev->dev, "Dropping packet due to invalid netdev or device\n");
 		return NULL;

net/dsa/tag_mtk.c

@@ -81,6 +81,9 @@ static struct sk_buff *mtk_tag_rcv(struct sk_buff *skb, struct net_device *dev,
 	if (!ds->ports[port].netdev)
 		return NULL;
 
+	if (unlikely(ds->cpu_port_mask & BIT(port)))
+		return NULL;
+
 	skb->dev = ds->ports[port].netdev;
 
 	return skb;

net/dsa/tag_qca.c

@@ -104,6 +104,9 @@ static struct sk_buff *qca_tag_rcv(struct sk_buff *skb, struct net_device *dev,
 	if (!ds->ports[port].netdev)
 		return NULL;
 
+	if (unlikely(ds->cpu_port_mask & BIT(port)))
+		return NULL;
+
 	/* Update skb & forward the frame accordingly */
 	skb->dev = ds->ports[port].netdev;
 

net/dsa/tag_trailer.c

@@ -76,6 +76,9 @@ static struct sk_buff *trailer_rcv(struct sk_buff *skb, struct net_device *dev,
 	if (source_port >= ds->num_ports || !ds->ports[source_port].netdev)
 		return NULL;
 
+	if (unlikely(ds->cpu_port_mask & BIT(source_port)))
+		return NULL;
+
 	pskb_trim_rcsum(skb, skb->len - 4);
 
 	skb->dev = ds->ports[source_port].netdev;