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 A17D6C5DF9D for ; Tue, 27 Oct 2020 16:16:35 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 4FBC021D7B for ; Tue, 27 Oct 2020 16:16:35 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1603815395; bh=mC850BtUPyQyxAiIbjrSA7Akdc3PkFFaza2+c8Ovwgc=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=zsxHQPazZZmq3V7IWfVe5axsAgAtvsxHCuTpa3slAoP5wTex28ueIFdHzlfBIyn9z RdsjjYTWpmQe2NOFP+QlmwltSDzGrCwQM+YiuKPbvCPQ9Hi5A+wLVB6Wrbdm8xLpRI v+2TnxlpjhfZRpg7fm0jfhJlJK0g2PoPHab23fIw= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1806255AbgJ0QGF (ORCPT ); Tue, 27 Oct 2020 12:06:05 -0400 Received: from mail.kernel.org ([198.145.29.99]:42512 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1802062AbgJ0Ppa (ORCPT ); Tue, 27 Oct 2020 11:45:30 -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 6396F21D42; Tue, 27 Oct 2020 15:45:29 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1603813530; bh=mC850BtUPyQyxAiIbjrSA7Akdc3PkFFaza2+c8Ovwgc=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=WyUPj/9lSiy3ngblp7fPohqcm61rsaC7SILvuoF2BhXYSZM/4sDoOjgQOe9UIRBRe tIDQ9+3msBFx1NTJxtPw1FQocsohQ8HkbsWxopnccvrKr9umarXmcCOzvKEb9mYcJZ SfLbLQFppoDHsnOaoAD0HEzbM51F0YZhpL1JaUeI= 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 5.9 575/757] netfilter: conntrack: connection timeout after re-register Date: Tue, 27 Oct 2020 14:53:45 +0100 Message-Id: <20201027135517.483770959@linuxfoundation.org> X-Mailer: git-send-email 2.29.1 In-Reply-To: <20201027135450.497324313@linuxfoundation.org> References: <20201027135450.497324313@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 e8c86ee4c1c48..c8fb2187ad4b2 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