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=-10.1 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,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 74B14C32750 for ; Fri, 2 Aug 2019 13:34:02 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 49AFB20665 for ; Fri, 2 Aug 2019 13:34:02 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1564752842; bh=luGPwrsMzBhqsBsjmDOagWeS2+zn0+WUsPIMCrUf+ek=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=UuWx+M9FxBoikQvO63ELFNdAgSC7piTKt2rairo8nf7mUURpOr6biqObt9/4jZcJw EgSv7QV7lAxH2hryu0HZZnGi4ms36U8r3DKMbSoyVPvtROeX8rwK5etuzEQku+ffQg Wlnjf40wqWHlcpOQoAof18gDJeKqgJZoluzhxhek= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2391921AbfHBNds (ORCPT ); Fri, 2 Aug 2019 09:33:48 -0400 Received: from mail.kernel.org ([198.145.29.99]:33712 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1732368AbfHBNXJ (ORCPT ); Fri, 2 Aug 2019 09:23:09 -0400 Received: from sasha-vm.mshome.net (c-73-47-72-35.hsd1.nh.comcast.net [73.47.72.35]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 683F1217D4; Fri, 2 Aug 2019 13:23:07 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1564752188; bh=luGPwrsMzBhqsBsjmDOagWeS2+zn0+WUsPIMCrUf+ek=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=IcDq8NHDwgNXWO2A4JXS5/mZGzyrBAZN0eOy4G87/fPxPKF8oxoVvZnXsFd+/tfk7 3r1bY59tU23JiLeZkKsSLGgg7NRTMEPb9PYCB220EQ5LwlQrnHRhJeqY3W3ExZzPx1 +weWoBhG8fe65bmLzIcclTnSXP74wbgNTrIM3bBk= From: Sasha Levin To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Florian Westphal , Jakub Jankowski , Jozsef Kadlecsik , Pablo Neira Ayuso , Sasha Levin , netfilter-devel@vger.kernel.org, coreteam@netfilter.org, netdev@vger.kernel.org Subject: [PATCH AUTOSEL 4.19 04/42] netfilter: conntrack: always store window size un-scaled Date: Fri, 2 Aug 2019 09:22:24 -0400 Message-Id: <20190802132302.13537-4-sashal@kernel.org> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20190802132302.13537-1-sashal@kernel.org> References: <20190802132302.13537-1-sashal@kernel.org> MIME-Version: 1.0 X-stable: review X-Patchwork-Hint: Ignore Content-Transfer-Encoding: 8bit Sender: netfilter-devel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netfilter-devel@vger.kernel.org From: Florian Westphal [ Upstream commit 959b69ef57db00cb33e9c4777400ae7183ebddd3 ] Jakub Jankowski reported following oddity: After 3 way handshake completes, timeout of new connection is set to max_retrans (300s) instead of established (5 days). shortened excerpt from pcap provided: 25.070622 IP (flags [DF], proto TCP (6), length 52) 10.8.5.4.1025 > 10.8.1.2.80: Flags [S], seq 11, win 64240, [wscale 8] 26.070462 IP (flags [DF], proto TCP (6), length 48) 10.8.1.2.80 > 10.8.5.4.1025: Flags [S.], seq 82, ack 12, win 65535, [wscale 3] 27.070449 IP (flags [DF], proto TCP (6), length 40) 10.8.5.4.1025 > 10.8.1.2.80: Flags [.], ack 83, win 512, length 0 Turns out the last_win is of u16 type, but we store the scaled value: 512 << 8 (== 0x20000) becomes 0 window. The Fixes tag is not correct, as the bug has existed forever, but without that change all that this causes might cause is to mistake a window update (to-nonzero-from-zero) for a retransmit. Fixes: fbcd253d2448b8 ("netfilter: conntrack: lower timeout to RETRANS seconds if window is 0") Reported-by: Jakub Jankowski Tested-by: Jakub Jankowski Signed-off-by: Florian Westphal Acked-by: Jozsef Kadlecsik Signed-off-by: Pablo Neira Ayuso Signed-off-by: Sasha Levin --- net/netfilter/nf_conntrack_proto_tcp.c | 8 +++++--- 1 file changed, 5 insertions(+), 3 deletions(-) diff --git a/net/netfilter/nf_conntrack_proto_tcp.c b/net/netfilter/nf_conntrack_proto_tcp.c index 842f3f86fb2e7..7011ab27c4371 100644 --- a/net/netfilter/nf_conntrack_proto_tcp.c +++ b/net/netfilter/nf_conntrack_proto_tcp.c @@ -480,6 +480,7 @@ static bool tcp_in_window(const struct nf_conn *ct, struct ip_ct_tcp_state *receiver = &state->seen[!dir]; const struct nf_conntrack_tuple *tuple = &ct->tuplehash[dir].tuple; __u32 seq, ack, sack, end, win, swin; + u16 win_raw; s32 receiver_offset; bool res, in_recv_win; @@ -488,7 +489,8 @@ static bool tcp_in_window(const struct nf_conn *ct, */ seq = ntohl(tcph->seq); ack = sack = ntohl(tcph->ack_seq); - win = ntohs(tcph->window); + win_raw = ntohs(tcph->window); + win = win_raw; end = segment_seq_plus_len(seq, skb->len, dataoff, tcph); if (receiver->flags & IP_CT_TCP_FLAG_SACK_PERM) @@ -663,14 +665,14 @@ static bool tcp_in_window(const struct nf_conn *ct, && state->last_seq == seq && state->last_ack == ack && state->last_end == end - && state->last_win == win) + && state->last_win == win_raw) state->retrans++; else { state->last_dir = dir; state->last_seq = seq; state->last_ack = ack; state->last_end = end; - state->last_win = win; + state->last_win = win_raw; state->retrans = 0; } } -- 2.20.1