From: Sasha Levin <sashal@kernel.org>
To: linux-kernel@vger.kernel.org, stable@vger.kernel.org
Cc: Florian Westphal <fw@strlen.de>,
Jakub Jankowski <shasta@toxcorp.com>,
Jozsef Kadlecsik <kadlec@blackhole.kfki.hu>,
Pablo Neira Ayuso <pablo@netfilter.org>,
Sasha Levin <sashal@kernel.org>,
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 [thread overview]
Message-ID: <20190802132302.13537-4-sashal@kernel.org> (raw)
In-Reply-To: <20190802132302.13537-1-sashal@kernel.org>
From: Florian Westphal <fw@strlen.de>
[ 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 <shasta@toxcorp.com>
Tested-by: Jakub Jankowski <shasta@toxcorp.com>
Signed-off-by: Florian Westphal <fw@strlen.de>
Acked-by: Jozsef Kadlecsik <kadlec@blackhole.kfki.hu>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
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
next prev parent reply other threads:[~2019-08-02 13:34 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-08-02 13:22 [PATCH AUTOSEL 4.19 01/42] netfilter: nfnetlink: avoid deadlock due to synchronous request_module Sasha Levin
2019-08-02 13:22 ` [PATCH AUTOSEL 4.19 03/42] netfilter: Fix rpfilter dropping vrf packets by mistake Sasha Levin
2019-08-02 13:22 ` Sasha Levin [this message]
2019-08-08 9:02 ` [PATCH AUTOSEL 4.19 04/42] netfilter: conntrack: always store window size un-scaled Thomas Jarosch
2019-08-14 10:19 ` Reindl Harald
2019-08-14 11:17 ` Jakub Jankowski
2019-08-14 17:01 ` Sasha Levin
2019-08-02 13:22 ` [PATCH AUTOSEL 4.19 05/42] netfilter: nft_hash: fix symhash with modulus one Sasha Levin
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20190802132302.13537-4-sashal@kernel.org \
--to=sashal@kernel.org \
--cc=coreteam@netfilter.org \
--cc=fw@strlen.de \
--cc=kadlec@blackhole.kfki.hu \
--cc=linux-kernel@vger.kernel.org \
--cc=netdev@vger.kernel.org \
--cc=netfilter-devel@vger.kernel.org \
--cc=pablo@netfilter.org \
--cc=shasta@toxcorp.com \
--cc=stable@vger.kernel.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).