1 files changed, 27 insertions, 12 deletions

diff --git a/net/ipv4/tcp_ipv4.c b/net/ipv4/tcp_ipv4.c
index 65b8ebfd078a..f4df5f931f36 100644
--- a/net/ipv4/tcp_ipv4.c
+++ b/net/ipv4/tcp_ipv4.c
@@ -370,6 +370,11 @@ void tcp_v4_err(struct sk_buff *icmp_skb, u32 info)
         if (sk->sk_state == TCP_CLOSE)
                 goto out;
 
+        if (unlikely(iph->ttl < inet_sk(sk)->min_ttl)) {
+                NET_INC_STATS_BH(net, LINUX_MIB_TCPMINTTLDROP);
+                goto out;
+        }
+
         icsk = inet_csk(sk);
         tp = tcp_sk(sk);
         seq = ntohl(th->seq);
@@ -742,9 +747,9 @@ static void tcp_v4_reqsk_send_ack(struct sock *sk, struct sk_buff *skb,
  *      This still operates on a request_sock only, not on a big
  *      socket.
  */
-static int __tcp_v4_send_synack(struct sock *sk, struct dst_entry *dst,
-                                struct request_sock *req,
-                                struct request_values *rvp)
+static int tcp_v4_send_synack(struct sock *sk, struct dst_entry *dst,
+                              struct request_sock *req,
+                              struct request_values *rvp)
 {
         const struct inet_request_sock *ireq = inet_rsk(req);
         int err = -1;
@@ -775,10 +780,11 @@ static int __tcp_v4_send_synack(struct sock *sk, struct dst_entry *dst,
         return err;
 }
 
-static int tcp_v4_send_synack(struct sock *sk, struct request_sock *req,
+static int tcp_v4_rtx_synack(struct sock *sk, struct request_sock *req,
                               struct request_values *rvp)
 {
-        return __tcp_v4_send_synack(sk, NULL, req, rvp);
+        TCP_INC_STATS_BH(sock_net(sk), TCP_MIB_RETRANSSEGS);
+        return tcp_v4_send_synack(sk, NULL, req, rvp);
 }
 
 /*
@@ -1192,10 +1198,11 @@ static int tcp_v4_inbound_md5_hash(struct sock *sk, struct sk_buff *skb)
 struct request_sock_ops tcp_request_sock_ops __read_mostly = {
         .family         =       PF_INET,
         .obj_size       =       sizeof(struct tcp_request_sock),
-        .rtx_syn_ack    =       tcp_v4_send_synack,
+        .rtx_syn_ack    =       tcp_v4_rtx_synack,
         .send_ack       =       tcp_v4_reqsk_send_ack,
         .destructor     =       tcp_v4_reqsk_destructor,
         .send_reset     =       tcp_v4_send_reset,
+        .syn_ack_timeout =      tcp_syn_ack_timeout,
 };
 
 #ifdef CONFIG_TCP_MD5SIG
@@ -1373,8 +1380,8 @@ int tcp_v4_conn_request(struct sock *sk, struct sk_buff *skb)
         }
         tcp_rsk(req)->snt_isn = isn;
 
-        if (__tcp_v4_send_synack(sk, dst, req,
-                                 (struct request_values *)&tmp_ext) ||
+        if (tcp_v4_send_synack(sk, dst, req,
+                               (struct request_values *)&tmp_ext) ||
             want_cookie)
                 goto drop_and_free;
 
@@ -1653,6 +1660,11 @@ process:
         if (sk->sk_state == TCP_TIME_WAIT)
                 goto do_time_wait;
 
+        if (unlikely(iph->ttl < inet_sk(sk)->min_ttl)) {
+                NET_INC_STATS_BH(net, LINUX_MIB_TCPMINTTLDROP);
+                goto discard_and_relse;
+        }
+
         if (!xfrm4_policy_check(sk, XFRM_POLICY_IN, skb))
                 goto discard_and_relse;
         nf_reset(skb);
@@ -1677,8 +1689,11 @@ process:
                         if (!tcp_prequeue(sk, skb))
                                 ret = tcp_v4_do_rcv(sk, skb);
                 }
-        } else
-                sk_add_backlog(sk, skb);
+        } else if (unlikely(sk_add_backlog(sk, skb))) {
+                bh_unlock_sock(sk);
+                NET_INC_STATS_BH(net, LINUX_MIB_TCPBACKLOGDROP);
+                goto discard_and_relse;
+        }
         bh_unlock_sock(sk);
 
         sock_put(sk);
@@ -2425,12 +2440,12 @@ static struct tcp_seq_afinfo tcp4_seq_afinfo = {
         },
 };
 
-static int tcp4_proc_init_net(struct net *net)
+static int __net_init tcp4_proc_init_net(struct net *net)
 {
         return tcp_proc_register(net, &tcp4_seq_afinfo);
 }
 
-static void tcp4_proc_exit_net(struct net *net)
+static void __net_exit tcp4_proc_exit_net(struct net *net)
 {
         tcp_proc_unregister(net, &tcp4_seq_afinfo);
 }