From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-12.8 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED, USER_AGENT_GIT autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 876AEC388F9 for ; Tue, 27 Oct 2020 17:33:47 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 38DB621D24 for ; Tue, 27 Oct 2020 17:33:47 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1603820027; bh=AHPu6VlPpb0XC/2887H1Sa35fVDy3w65m8Olms9NGyU=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=XLk7fj5/utHBNz4vjX8/KmzImOKMPT2z7WTsXv1AWrzsKRQYqjz1YtmmfSl9nV8iv 5vj8IrYm+jQjWqjTl5BQ/Jxh1zXuYVaId4d996afE1Nd7L0b/XMjc52Ug6NVxYIpKY pJx+QVW+fHiCZR+QfBRZQ94EBVzyTxwy+4evaH1Q= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1820192AbgJ0Rdo (ORCPT ); Tue, 27 Oct 2020 13:33:44 -0400 Received: from mail.kernel.org ([198.145.29.99]:41262 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1762292AbgJ0Olt (ORCPT ); Tue, 27 Oct 2020 10:41:49 -0400 Received: from localhost (83-86-74-64.cable.dynamic.v4.ziggo.nl [83.86.74.64]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 0BCC9207BB; Tue, 27 Oct 2020 14:41:47 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1603809708; bh=AHPu6VlPpb0XC/2887H1Sa35fVDy3w65m8Olms9NGyU=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=W4SFxVgC7mEbllbksON1t52cg9k5cRzqML/7S0imE6xlwMe9TybnECTr+DaFfLnfW l6uuasv3b0XHrV234Q5XutJ4Wh3Q9o2X5lPoGCAaYrhFPjZXXmPiWgK3tQWcInhtGv 9qGpAY/hxWLz+OURyw8kDlSwINKzxzSInscJNKQI= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Francesco Ruggeri , Pablo Neira Ayuso , Sasha Levin Subject: [PATCH 5.4 292/408] netfilter: conntrack: connection timeout after re-register Date: Tue, 27 Oct 2020 14:53:50 +0100 Message-Id: <20201027135508.585157601@linuxfoundation.org> X-Mailer: git-send-email 2.29.1 In-Reply-To: <20201027135455.027547757@linuxfoundation.org> References: <20201027135455.027547757@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Francesco Ruggeri [ Upstream commit 4f25434bccc28cf8a07876ef5142a2869a674353 ] If the first packet conntrack sees after a re-register is an outgoing keepalive packet with no data (SEG.SEQ = SND.NXT-1), td_end is set to SND.NXT-1. When the peer correctly acknowledges SND.NXT, tcp_in_window fails check III (Upper bound for valid (s)ack: sack <= receiver.td_end) and returns false, which cascades into nf_conntrack_in setting skb->_nfct = 0 and in later conntrack iptables rules not matching. In cases where iptables are dropping packets that do not match conntrack rules this can result in idle tcp connections to time out. v2: adjust td_end when getting the reply rather than when sending out the keepalive packet. Fixes: f94e63801ab2 ("netfilter: conntrack: reset tcp maxwin on re-register") Signed-off-by: Francesco Ruggeri Signed-off-by: Pablo Neira Ayuso Signed-off-by: Sasha Levin --- net/netfilter/nf_conntrack_proto_tcp.c | 19 +++++++++++++------ 1 file changed, 13 insertions(+), 6 deletions(-) diff --git a/net/netfilter/nf_conntrack_proto_tcp.c b/net/netfilter/nf_conntrack_proto_tcp.c index 1926fd56df56a..848b137151c26 100644 --- a/net/netfilter/nf_conntrack_proto_tcp.c +++ b/net/netfilter/nf_conntrack_proto_tcp.c @@ -541,13 +541,20 @@ static bool tcp_in_window(const struct nf_conn *ct, swin = win << sender->td_scale; sender->td_maxwin = (swin == 0 ? 1 : swin); sender->td_maxend = end + sender->td_maxwin; - /* - * We haven't seen traffic in the other direction yet - * but we have to tweak window tracking to pass III - * and IV until that happens. - */ - if (receiver->td_maxwin == 0) + if (receiver->td_maxwin == 0) { + /* We haven't seen traffic in the other + * direction yet but we have to tweak window + * tracking to pass III and IV until that + * happens. + */ receiver->td_end = receiver->td_maxend = sack; + } else if (sack == receiver->td_end + 1) { + /* Likely a reply to a keepalive. + * Needed for III. + */ + receiver->td_end++; + } + } } else if (((state->state == TCP_CONNTRACK_SYN_SENT && dir == IP_CT_DIR_ORIGINAL) -- 2.25.1