From: Wei Wang <wei...@google.com>
When tcp_disconnect() is called, inet_csk_delack_init() sets
icsk->icsk_ack.rcv_mss to 0.
This could potentially cause tcp_recvmsg() => tcp_cleanup_rbuf() =>
__tcp_select_window() call path to have division by 0 issue.
So this patch initializes rcv_mss to TCP_MIN_MSS instead of 0.
Reported-by: Andrey Konovalov <andreyk...@google.com>
Signed-off-by: Wei Wang <wei...@google.com>
Signed-off-by: Eric Dumazet <eduma...@google.com>
Signed-off-by: Neal Cardwell <ncardw...@google.com>
Signed-off-by: Yuchung Cheng <ych...@google.com>
---
net/ipv4/tcp.c | 4 ++++
1 file changed, 4 insertions(+)
diff --git a/net/ipv4/tcp.c b/net/ipv4/tcp.c
index 1e4c76d2b827..842b575f8fdd 100644
--- a/net/ipv4/tcp.c
+++ b/net/ipv4/tcp.c
@@ -2320,6 +2320,10 @@ int tcp_disconnect(struct sock *sk, int flags)
tcp_set_ca_state(sk, TCP_CA_Open);
tcp_clear_retrans(tp);
inet_csk_delack_init(sk);
+ /* Initialize rcv_mss to TCP_MIN_MSS to avoid division by 0
+ * issue in __tcp_select_window()
+ */
+ icsk->icsk_ack.rcv_mss = TCP_MIN_MSS;
tcp_init_send_head(sk);
memset(&tp->rx_opt, 0, sizeof(tp->rx_opt));
__sk_dst_reset(sk);
--
2.13.0.303.g4ebf302169-goog
