1 files changed, 17 insertions, 8 deletions

diff --git a/net/ipv4/tcp_ipv4.c b/net/ipv4/tcp_ipv4.c
index 0c50c5a32b84..e0cef75f85fb 100644
--- a/net/ipv4/tcp_ipv4.c
+++ b/net/ipv4/tcp_ipv4.c
@@ -154,6 +154,12 @@ int tcp_twsk_unique(struct sock *sk, struct sock *sktw, void *twp)
 	if (tcptw->tw_ts_recent_stamp &&
 	    (!twp || (reuse && time_after32(ktime_get_seconds(),
 					    tcptw->tw_ts_recent_stamp)))) {
+		/* inet_twsk_hashdance() sets sk_refcnt after putting twsk
+		 * and releasing the bucket lock.
+		 */
+		if (unlikely(!refcount_inc_not_zero(&sktw->sk_refcnt)))
+			return 0;
+
 		/* In case of repair and re-using TIME-WAIT sockets we still
 		 * want to be sure that it is safe as above but honor the
 		 * sequence numbers and time stamps set as part of the repair
@@ -174,7 +180,7 @@ int tcp_twsk_unique(struct sock *sk, struct sock *sktw, void *twp)
 			tp->rx_opt.ts_recent	   = tcptw->tw_ts_recent;
 			tp->rx_opt.ts_recent_stamp = tcptw->tw_ts_recent_stamp;
 		}
-		sock_hold(sktw);
+
 		return 1;
 	}
 
@@ -1907,7 +1913,6 @@ int tcp_v4_do_rcv(struct sock *sk, struct sk_buff *skb)
 		return 0;
 	}
 
-	reason = SKB_DROP_REASON_NOT_SPECIFIED;
 	if (tcp_checksum_complete(skb))
 		goto csum_err;
 
@@ -1915,9 +1920,10 @@ int tcp_v4_do_rcv(struct sock *sk, struct sk_buff *skb)
 		struct sock *nsk = tcp_v4_cookie_check(sk, skb);
 
 		if (!nsk)
-			goto discard;
+			return 0;
 		if (nsk != sk) {
-			if (tcp_child_process(sk, nsk, skb)) {
+			reason = tcp_child_process(sk, nsk, skb);
+			if (reason) {
 				rsk = nsk;
 				goto reset;
 			}
@@ -1926,7 +1932,8 @@ int tcp_v4_do_rcv(struct sock *sk, struct sk_buff *skb)
 	} else
 		sock_rps_save_rxhash(sk, skb);
 
-	if (tcp_rcv_state_process(sk, skb)) {
+	reason = tcp_rcv_state_process(sk, skb);
+	if (reason) {
 		rsk = sk;
 		goto reset;
 	}
@@ -2275,10 +2282,12 @@ process:
 		if (nsk == sk) {
 			reqsk_put(req);
 			tcp_v4_restore_cb(skb);
-		} else if (tcp_child_process(sk, nsk, skb)) {
-			tcp_v4_send_reset(nsk, skb);
-			goto discard_and_relse;
 		} else {
+			drop_reason = tcp_child_process(sk, nsk, skb);
+			if (drop_reason) {
+				tcp_v4_send_reset(nsk, skb);
+				goto discard_and_relse;
+			}
 			sock_put(sk);
 			return 0;
 		}