1 files changed, 60 insertions, 8 deletions

diff --git a/net/ipv4/inet_hashtables.c b/net/ipv4/inet_hashtables.c
index 8cbe74313f38..45fb450b4522 100644
--- a/net/ipv4/inet_hashtables.c
+++ b/net/ipv4/inet_hashtables.c
@@ -20,6 +20,9 @@
 #include <net/addrconf.h>
 #include <net/inet_connection_sock.h>
 #include <net/inet_hashtables.h>
+#if IS_ENABLED(CONFIG_IPV6)
+#include <net/inet6_hashtables.h>
+#endif
 #include <net/secure_seq.h>
 #include <net/ip.h>
 #include <net/tcp.h>
@@ -508,10 +511,52 @@ static u32 inet_sk_port_offset(const struct sock *sk)
 					  inet->inet_dport);
 }
 
-/* insert a socket into ehash, and eventually remove another one
- * (The another one can be a SYN_RECV or TIMEWAIT
+/* Searches for an exsiting socket in the ehash bucket list.
+ * Returns true if found, false otherwise.
  */
-bool inet_ehash_insert(struct sock *sk, struct sock *osk)
+static bool inet_ehash_lookup_by_sk(struct sock *sk,
+				    struct hlist_nulls_head *list)
+{
+	const __portpair ports = INET_COMBINED_PORTS(sk->sk_dport, sk->sk_num);
+	const int sdif = sk->sk_bound_dev_if;
+	const int dif = sk->sk_bound_dev_if;
+	const struct hlist_nulls_node *node;
+	struct net *net = sock_net(sk);
+	struct sock *esk;
+
+	INET_ADDR_COOKIE(acookie, sk->sk_daddr, sk->sk_rcv_saddr);
+
+	sk_nulls_for_each_rcu(esk, node, list) {
+		if (esk->sk_hash != sk->sk_hash)
+			continue;
+		if (sk->sk_family == AF_INET) {
+			if (unlikely(INET_MATCH(esk, net, acookie,
+						sk->sk_daddr,
+						sk->sk_rcv_saddr,
+						ports, dif, sdif))) {
+				return true;
+			}
+		}
+#if IS_ENABLED(CONFIG_IPV6)
+		else if (sk->sk_family == AF_INET6) {
+			if (unlikely(INET6_MATCH(esk, net,
+						 &sk->sk_v6_daddr,
+						 &sk->sk_v6_rcv_saddr,
+						 ports, dif, sdif))) {
+				return true;
+			}
+		}
+#endif
+	}
+	return false;
+}
+
+/* Insert a socket into ehash, and eventually remove another one
+ * (The another one can be a SYN_RECV or TIMEWAIT)
+ * If an existing socket already exists, socket sk is not inserted,
+ * and sets found_dup_sk parameter to true.
+ */
+bool inet_ehash_insert(struct sock *sk, struct sock *osk, bool *found_dup_sk)
 {
 	struct inet_hashinfo *hashinfo = sk->sk_prot->h.hashinfo;
 	struct hlist_nulls_head *list;
@@ -530,16 +575,23 @@ bool inet_ehash_insert(struct sock *sk, struct sock *osk)
 	if (osk) {
 		WARN_ON_ONCE(sk->sk_hash != osk->sk_hash);
 		ret = sk_nulls_del_node_init_rcu(osk);
+	} else if (found_dup_sk) {
+		*found_dup_sk = inet_ehash_lookup_by_sk(sk, list);
+		if (*found_dup_sk)
+			ret = false;
 	}
+
 	if (ret)
 		__sk_nulls_add_node_rcu(sk, list);
+
 	spin_unlock(lock);
+
 	return ret;
 }
 
-bool inet_ehash_nolisten(struct sock *sk, struct sock *osk)
+bool inet_ehash_nolisten(struct sock *sk, struct sock *osk, bool *found_dup_sk)
 {
-	bool ok = inet_ehash_insert(sk, osk);
+	bool ok = inet_ehash_insert(sk, osk, found_dup_sk);
 
 	if (ok) {
 		sock_prot_inuse_add(sock_net(sk), sk->sk_prot, 1);
@@ -583,7 +635,7 @@ int __inet_hash(struct sock *sk, struct sock *osk)
 	int err = 0;
 
 	if (sk->sk_state != TCP_LISTEN) {
-		inet_ehash_nolisten(sk, osk);
+		inet_ehash_nolisten(sk, osk, NULL);
 		return 0;
 	}
 	WARN_ON(!sk_unhashed(sk));
@@ -679,7 +731,7 @@ int __inet_hash_connect(struct inet_timewait_death_row *death_row,
 		tb = inet_csk(sk)->icsk_bind_hash;
 		spin_lock_bh(&head->lock);
 		if (sk_head(&tb->owners) == sk && !sk->sk_bind_node.next) {
-			inet_ehash_nolisten(sk, NULL);
+			inet_ehash_nolisten(sk, NULL, NULL);
 			spin_unlock_bh(&head->lock);
 			return 0;
 		}
@@ -758,7 +810,7 @@ ok:
 	inet_bind_hash(sk, tb, port);
 	if (sk_unhashed(sk)) {
 		inet_sk(sk)->inet_sport = htons(port);
-		inet_ehash_nolisten(sk, (struct sock *)tw);
+		inet_ehash_nolisten(sk, (struct sock *)tw, NULL);
 	}
 	if (tw)
 		inet_twsk_bind_unhash(tw, hinfo);