bridge: Validate that vlan is permitted on ingress

When a frame arrives on a port or transmitted by the bridge,
if we have VLANs configured, validate that a given VLAN is allowed
to enter the bridge.

Signed-off-by: Vlad Yasevich <vyasevic@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

4 files changed, 85 insertions, 0 deletions

diff --git a/net/bridge/br_device.c b/net/bridge/br_device.c
index ca98fa5b2c78..35a2c2c84f33 100644
--- a/net/bridge/br_device.c
+++ b/net/bridge/br_device.c
@@ -45,6 +45,9 @@ netdev_tx_t br_dev_xmit(struct sk_buff *skb, struct net_device *dev)
         brstats->tx_bytes += skb->len;
         u64_stats_update_end(&brstats->syncp);
 
+        if (!br_allowed_ingress(br, br_get_vlan_info(br), skb))
+                goto out;
+
         BR_INPUT_SKB_CB(skb)->brdev = dev;
 
         skb_reset_mac_header(skb);
diff --git a/net/bridge/br_input.c b/net/bridge/br_input.c
index 4b34207419b1..4ef3f6b17bd0 100644
--- a/net/bridge/br_input.c
+++ b/net/bridge/br_input.c
@@ -17,6 +17,7 @@
 #include <linux/etherdevice.h>
 #include <linux/netfilter_bridge.h>
 #include <linux/export.h>
+#include <linux/rculist.h>
 #include "br_private.h"
 
 /* Hook for brouter */
@@ -54,6 +55,9 @@ int br_handle_frame_finish(struct sk_buff *skb)
         if (!p || p->state == BR_STATE_DISABLED)
                 goto drop;
 
+        if (!br_allowed_ingress(p->br, nbp_get_vlan_info(p), skb))
+                goto drop;
+
         /* insert into forwarding database after filtering to avoid spoofing */
         br = p->br;
         br_fdb_update(br, p, eth_hdr(skb)->h_source);
diff --git a/net/bridge/br_private.h b/net/bridge/br_private.h
index 1f3b309beea8..ed7c764ee9da 100644
--- a/net/bridge/br_private.h
+++ b/net/bridge/br_private.h
@@ -552,6 +552,8 @@ static inline void br_mdb_uninit(void)
 
 /* br_vlan.c */
 #ifdef CONFIG_BRIDGE_VLAN_FILTERING
+extern bool br_allowed_ingress(struct net_bridge *br, struct net_port_vlans *v,
+                               struct sk_buff *skb);
 extern int br_vlan_add(struct net_bridge *br, u16 vid);
 extern int br_vlan_delete(struct net_bridge *br, u16 vid);
 extern void br_vlan_flush(struct net_bridge *br);
@@ -559,7 +561,43 @@ extern int br_vlan_filter_toggle(struct net_bridge *br, unsigned long val);
 extern int nbp_vlan_add(struct net_bridge_port *port, u16 vid);
 extern int nbp_vlan_delete(struct net_bridge_port *port, u16 vid);
 extern void nbp_vlan_flush(struct net_bridge_port *port);
+
+static inline struct net_port_vlans *br_get_vlan_info(
+                                                const struct net_bridge *br)
+{
+        return rcu_dereference(br->vlan_info);
+}
+
+static inline struct net_port_vlans *nbp_get_vlan_info(
+                                                const struct net_bridge_port *p)
+{
+        return rcu_dereference(p->vlan_info);
+}
+
+/* Since bridge now depends on 8021Q module, but the time bridge sees the
+ * skb, the vlan tag will always be present if the frame was tagged.
+ */
+static inline int br_vlan_get_tag(const struct sk_buff *skb, u16 *vid)
+{
+        int err = 0;
+
+        if (vlan_tx_tag_present(skb))
+                *vid = vlan_tx_tag_get(skb) & VLAN_VID_MASK;
+        else {
+                *vid = 0;
+                err = -EINVAL;
+        }
+
+        return err;
+}
 #else
+static inline bool br_allowed_ingress(struct net_bridge *br,
+                                      struct net_port_vlans *v,
+                                      struct sk_buff *skb)
+{
+        return true;
+}
+
 static inline int br_vlan_add(struct net_bridge *br, u16 vid)
 {
         return -EOPNOTSUPP;
@@ -588,6 +626,21 @@ static inline void nbp_vlan_flush(struct net_bridge_port *port)
 {
 }
 
+static inline struct net_port_vlans *br_get_vlan_info(
+                                                const struct net_bridge *br)
+{
+        return NULL;
+}
+static inline struct net_port_vlans *nbp_get_vlan_info(
+                                                const struct net_bridge_port *p)
+{
+        return NULL;
+}
+
+static inline u16 br_vlan_get_tag(const struct sk_buff *skb)
+{
+        return 0;
+}
 #endif
 
 /* br_netfilter.c */
diff --git a/net/bridge/br_vlan.c b/net/bridge/br_vlan.c
index 209464ef5242..8b4bcd8ff46e 100644
--- a/net/bridge/br_vlan.c
+++ b/net/bridge/br_vlan.c
@@ -64,6 +64,31 @@ static void __vlan_flush(struct net_port_vlans *v)
         kfree_rcu(v, rcu);
 }
 
+/* Called under RCU */
+bool br_allowed_ingress(struct net_bridge *br, struct net_port_vlans *v,
+                        struct sk_buff *skb)
+{
+        u16 vid;
+
+        /* If VLAN filtering is disabled on the bridge, all packets are
+         * permitted.
+         */
+        if (!br->vlan_enabled)
+                return true;
+
+        /* If there are no vlan in the permitted list, all packets are
+         * rejected.
+         */
+        if (!v)
+                return false;
+
+        br_vlan_get_tag(skb, &vid);
+        if (test_bit(vid, v->vlan_bitmap))
+                return true;
+
+        return false;
+}
+
 /* Must be protected by RTNL */
 int br_vlan_add(struct net_bridge *br, u16 vid)
 {