tcp: should drop incoming frames without ACK flag set

[platform/adaptation/renesas_rcar/renesas_kernel.git] / net / ipv4 / tcp_input.c

diff --git a/net/ipv4/tcp_input.c b/net/ipv4/tcp_input.c
index a136925..a28e4db 100644 (file)
--- a/net/ipv4/tcp_input.c
+++ b/net/ipv4/tcp_input.c
@@ -5543,6 +5543,9 @@ slow_path:
        if (len < (th->doff << 2) || tcp_checksum_complete_user(sk, skb))
                goto csum_error;
 
+       if (!th->ack)
+               goto discard;
+
        /*
         *      Standard slow path.
         */
@@ -5551,7 +5554,7 @@ slow_path:
                return 0;
 
 step5:
-       if (th->ack && tcp_ack(sk, skb, FLAG_SLOWPATH) < 0)
+       if (tcp_ack(sk, skb, FLAG_SLOWPATH) < 0)
                goto discard;
 
        /* ts_recent update must be made after we are sure that the packet
@@ -5984,11 +5987,15 @@ int tcp_rcv_state_process(struct sock *sk, struct sk_buff *skb,
                if (tcp_check_req(sk, skb, req, NULL, true) == NULL)
                        goto discard;
        }
+
+       if (!th->ack)
+               goto discard;
+
        if (!tcp_validate_incoming(sk, skb, th, 0))
                return 0;
 
        /* step 5: check the ACK field */
-       if (th->ack) {
+       if (true) {
                int acceptable = tcp_ack(sk, skb, FLAG_SLOWPATH) > 0;
 
                switch (sk->sk_state) {
@@ -6138,8 +6145,7 @@ int tcp_rcv_state_process(struct sock *sk, struct sk_buff *skb,
                        }
                        break;
                }
-       } else
-               goto discard;
+       }
 
        /* ts_recent update must be made after we are sure that the packet
         * is in window.