openvswitch: Reject ct_state masks for unknown bits

Currently, 0-bits are generated in ct_state where the bit position is
undefined, and matches are accepted on these bit-positions. If userspace
requests to match the 0-value for this bit then it may expect only a
subset of traffic to match this value, whereas currently all packets
will have this bit set to 0. Fix this by rejecting such masks.

Signed-off-by: Joe Stringer <joestringer@nicira.com>
Acked-by: Pravin B Shelar <pshelar@nicira.com>
Acked-by: Thomas Graf <tgraf@suug.ch>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/openvswitch/conntrack.h

@@ -35,12 +35,9 @@ void ovs_ct_fill_key(const struct sk_buff *skb, struct sw_flow_key *key);
 int ovs_ct_put_key(const struct sw_flow_key *key, struct sk_buff *skb);
 void ovs_ct_free_action(const struct nlattr *a);
 
-static inline bool ovs_ct_state_supported(u32 state)
-{
-	return !(state & ~(OVS_CS_F_NEW | OVS_CS_F_ESTABLISHED |
-			 OVS_CS_F_RELATED | OVS_CS_F_REPLY_DIR |
-			 OVS_CS_F_INVALID | OVS_CS_F_TRACKED));
-}
+#define CT_SUPPORTED_MASK (OVS_CS_F_NEW | OVS_CS_F_ESTABLISHED | \
+			   OVS_CS_F_RELATED | OVS_CS_F_REPLY_DIR | \
+			   OVS_CS_F_INVALID | OVS_CS_F_TRACKED)
 #else
 #include <linux/errno.h>
 
@@ -53,11 +50,6 @@ static inline bool ovs_ct_verify(struct net *net, int attr)
 	return false;
 }
 
-static inline bool ovs_ct_state_supported(u32 state)
-{
-	return false;
-}
-
 static inline int ovs_ct_copy_action(struct net *net, const struct nlattr *nla,
 				     const struct sw_flow_key *key,
 				     struct sw_flow_actions **acts, bool log)
@@ -94,5 +86,7 @@ static inline int ovs_ct_put_key(const struct sw_flow_key *key,
 }
 
 static inline void ovs_ct_free_action(const struct nlattr *a) { }
+
+#define CT_SUPPORTED_MASK 0
 #endif /* CONFIG_NF_CONNTRACK */
 #endif /* ovs_conntrack.h */

net/openvswitch/flow_netlink.c

@@ -816,7 +816,7 @@ static int metadata_from_nlattrs(struct net *net, struct sw_flow_match *match,
 	    ovs_ct_verify(net, OVS_KEY_ATTR_CT_STATE)) {
 		u32 ct_state = nla_get_u32(a[OVS_KEY_ATTR_CT_STATE]);
 
-		if (!is_mask && !ovs_ct_state_supported(ct_state)) {
+		if (ct_state & ~CT_SUPPORTED_MASK) {
 			OVS_NLERR(log, "ct_state flags %08x unsupported",
 				  ct_state);
 			return -EINVAL;
@@ -1099,6 +1099,9 @@ static void nlattr_set(struct nlattr *attr, u8 val,
 		} else {
 			memset(nla_data(nla), val, nla_len(nla));
 		}
+
+		if (nla_type(nla) == OVS_KEY_ATTR_CT_STATE)
+			*(u32 *)nla_data(nla) &= CT_SUPPORTED_MASK;
 	}
 }