Message ID | 20170518182233.100933-1-tracywwnj@gmail.com |
---|---|
State | Accepted, archived |
Delegated to: | David Miller |
Headers | show |
From: Wei Wang <weiwan@google.com> Date: Thu, 18 May 2017 11:22:33 -0700 > From: Wei Wang <weiwan@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 <andreyknvl@google.com> > Signed-off-by: Wei Wang <weiwan@google.com> > Signed-off-by: Eric Dumazet <edumazet@google.com> > Signed-off-by: Neal Cardwell <ncardwell@google.com> > Signed-off-by: Yuchung Cheng <ycheng@google.com> Applied, thanks.
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);