lkml.org 
[lkml]   [2017]   [Sep]   [9]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
From
Date
Subject[PATCH 3.2 098/106] tcp: initialize rcv_mss to TCP_MIN_MSS instead of 0
3.2.93-rc1 review patch.  If anyone has any objections, please let me know.

------------------

From: Wei Wang <weiwan@google.com>

commit 499350a5a6e7512d9ed369ed63a4244b6536f4f8 upstream.

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>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
---
net/ipv4/tcp.c | 4 ++++
1 file changed, 4 insertions(+)

--- a/net/ipv4/tcp.c
+++ b/net/ipv4/tcp.c
@@ -2106,6 +2106,10 @@ int tcp_disconnect(struct sock *sk, int
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);
\
 
 \ /
  Last update: 2017-09-10 00:56    [W:0.501 / U:2.340 seconds]
©2003-2017 Jasper Spaans. hosted at Digital OceanAdvertise on this site