From: Christoph Paasch <cpaasch@apple.com>
Date: Sat, 6 Jul 2019 16:13:07 -0700
Subject: tcp: Reset bytes_acked and bytes_received when disconnecting
Git-commit: e858faf556d4e14c750ba1e8852783c6f9520a0e
Patch-mainline: 5.3-rc1
References: networking-stable-19_07_25

If an app is playing tricks to reuse a socket via tcp_disconnect(),
bytes_acked/received needs to be reset to 0. Otherwise tcp_info will
report the sum of the current and the old connection..

Cc: Eric Dumazet <edumazet@google.com>
Fixes: 0df48c26d841 ("tcp: add tcpi_bytes_acked to tcp_info")
Fixes: bdd1f9edacb5 ("tcp: add tcpi_bytes_received to tcp_info")
Signed-off-by: Christoph Paasch <cpaasch@apple.com>
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
---
 net/ipv4/tcp.c |    2 ++
 1 file changed, 2 insertions(+)

--- a/net/ipv4/tcp.c
+++ b/net/ipv4/tcp.c
@@ -2233,6 +2233,8 @@ int tcp_disconnect(struct sock *sk, int
 	dst_release(sk->sk_rx_dst);
 	sk->sk_rx_dst = NULL;
 	tcp_saved_syn_free(tp);
+	tp->bytes_acked = 0;
+	tp->bytes_received = 0;
 
 	/* Clean up fastopen related fields */
 	tcp_free_fastopen_req(tp);