1 files changed, 24 insertions, 7 deletions

diff --git a/net/ipv4/tcp_input.c b/net/ipv4/tcp_input.c
index 432c36649db3..609ff98aeb47 100644
--- a/net/ipv4/tcp_input.c
+++ b/net/ipv4/tcp_input.c
@@ -4529,6 +4529,9 @@ int tcp_send_rcvq(struct sock *sk, struct msghdr *msg, size_t size)
         struct tcphdr *th;
         bool fragstolen;
 
+        if (size == 0)
+                return 0;
+
         skb = alloc_skb(size + sizeof(*th), sk->sk_allocation);
         if (!skb)
                 goto err;
@@ -5310,11 +5313,6 @@ static bool tcp_validate_incoming(struct sock *sk, struct sk_buff *skb,
                 goto discard;
         }
 
-        /* ts_recent update must be made after we are sure that the packet
-         * is in window.
-         */
-        tcp_replace_ts_recent(tp, TCP_SKB_CB(skb)->seq);
-
         /* step 3: check security and precedence [ignored] */
 
         /* step 4: Check for a SYN
@@ -5549,6 +5547,11 @@ step5:
         if (th->ack && tcp_ack(sk, skb, FLAG_SLOWPATH) < 0)
                 goto discard;
 
+        /* ts_recent update must be made after we are sure that the packet
+         * is in window.
+         */
+        tcp_replace_ts_recent(tp, TCP_SKB_CB(skb)->seq);
+
         tcp_rcv_rtt_measure_ts(sk, skb);
 
         /* Process urgent data. */
@@ -5646,6 +5649,7 @@ static bool tcp_rcv_fastopen_synack(struct sock *sk, struct sk_buff *synack,
                 tcp_rearm_rto(sk);
                 return true;
         }
+        tp->syn_data_acked = tp->syn_data;
         return false;
 }
 
@@ -5963,7 +5967,7 @@ int tcp_rcv_state_process(struct sock *sk, struct sk_buff *skb,
 
         req = tp->fastopen_rsk;
         if (req != NULL) {
-                BUG_ON(sk->sk_state != TCP_SYN_RECV &&
+                WARN_ON_ONCE(sk->sk_state != TCP_SYN_RECV &&
                     sk->sk_state != TCP_FIN_WAIT1);
 
                 if (tcp_check_req(sk, skb, req, NULL, true) == NULL)
@@ -6052,7 +6056,15 @@ int tcp_rcv_state_process(struct sock *sk, struct sk_buff *skb,
                          * ACK we have received, this would have acknowledged
                          * our SYNACK so stop the SYNACK timer.
                          */
-                        if (acceptable && req != NULL) {
+                        if (req != NULL) {
+                                /* Return RST if ack_seq is invalid.
+                                 * Note that RFC793 only says to generate a
+                                 * DUPACK for it but for TCP Fast Open it seems
+                                 * better to treat this case like TCP_SYN_RECV
+                                 * above.
+                                 */
+                                if (!acceptable)
+                                        return 1;
                                 /* We no longer need the request sock. */
                                 reqsk_fastopen_remove(sk, req, false);
                                 tcp_rearm_rto(sk);
@@ -6118,6 +6130,11 @@ int tcp_rcv_state_process(struct sock *sk, struct sk_buff *skb,
         } else
                 goto discard;
 
+        /* ts_recent update must be made after we are sure that the packet
+         * is in window.
+         */
+        tcp_replace_ts_recent(tp, TCP_SKB_CB(skb)->seq);
+
         /* step 6: check the URG bit */
         tcp_urg(sk, skb, th);