Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933710AbcKMLZH (ORCPT ); Sun, 13 Nov 2016 06:25:07 -0500 Received: from mail.linuxfoundation.org ([140.211.169.12]:35802 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932371AbcKMLZF (ORCPT ); Sun, 13 Nov 2016 06:25:05 -0500 From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Eric Dumazet , "David S. Miller" Subject: [PATCH 4.4 01/34] tcp: fix overflow in __tcp_retransmit_skb() Date: Sun, 13 Nov 2016 12:24:33 +0100 Message-Id: <20161113112400.076055382@linuxfoundation.org> X-Mailer: git-send-email 2.10.2 In-Reply-To: <20161113112400.008903838@linuxfoundation.org> References: <20161113112400.008903838@linuxfoundation.org> User-Agent: quilt/0.65 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1166 Lines: 39 4.4-stable review patch. If anyone has any objections, please let me know. ------------------ From: Eric Dumazet [ Upstream commit ffb4d6c8508657824bcef68a36b2a0f9d8c09d10 ] 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: Greg Kroah-Hartman --- net/ipv4/tcp_output.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) --- a/net/ipv4/tcp_output.c +++ b/net/ipv4/tcp_output.c @@ -2569,7 +2569,8 @@ int __tcp_retransmit_skb(struct sock *sk * 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 (skb_still_in_host_queue(sk, skb))