From mboxrd@z Thu Jan 1 00:00:00 1970 Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754575AbdBETqn (ORCPT + 2 others); Sun, 5 Feb 2017 14:46:43 -0500 Received: from wtarreau.pck.nerim.net ([62.212.114.60]:28283 "EHLO 1wt.eu" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752603AbdBET0j (ORCPT ); Sun, 5 Feb 2017 14:26:39 -0500 From: Willy Tarreau To: linux-kernel@vger.kernel.org, stable@vger.kernel.org, linux@roeck-us.net Cc: Eric Dumazet , "David S . Miller" , Willy Tarreau Subject: [PATCH 3.10 233/319] tcp: fix overflow in __tcp_retransmit_skb() Date: Sun, 5 Feb 2017 20:20:55 +0100 Message-Id: <1486322541-8206-134-git-send-email-w@1wt.eu> X-Mailer: git-send-email 2.8.0.rc2.1.gbe9624a In-Reply-To: <1486322541-8206-1-git-send-email-w@1wt.eu> References: <1486322541-8206-1-git-send-email-w@1wt.eu> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Return-Path: From: Eric Dumazet commit ffb4d6c8508657824bcef68a36b2a0f9d8c09d10 upstream. If a TCP socket gets a large write queue, an overflow can happen in a test in __tcp_retransmit_skb() preventing all retransmits. The flow then stalls and resets after timeouts. Tested: sysctl -w net.core.wmem_max=1000000000 netperf -H dest -- -s 1000000000 Signed-off-by: Eric Dumazet Signed-off-by: David S. Miller Signed-off-by: Willy Tarreau --- net/ipv4/tcp_output.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/net/ipv4/tcp_output.c b/net/ipv4/tcp_output.c index 276b283..465285b 100644 --- a/net/ipv4/tcp_output.c +++ b/net/ipv4/tcp_output.c @@ -2327,7 +2327,8 @@ int __tcp_retransmit_skb(struct sock *sk, struct sk_buff *skb) * copying overhead: fragmentation, tunneling, mangling etc. */ if (atomic_read(&sk->sk_wmem_alloc) > - min(sk->sk_wmem_queued + (sk->sk_wmem_queued >> 2), sk->sk_sndbuf)) + min_t(u32, sk->sk_wmem_queued + (sk->sk_wmem_queued >> 2), + sk->sk_sndbuf)) return -EAGAIN; if (before(TCP_SKB_CB(skb)->seq, tp->snd_una)) { -- 2.8.0.rc2.1.gbe9624a