1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
|
Return-Path: <lists@achow101.com>
Received: from smtp1.osuosl.org (smtp1.osuosl.org [140.211.166.138])
by lists.linuxfoundation.org (Postfix) with ESMTP id A585DC0032
for <bitcoin-dev@lists.linuxfoundation.org>;
Thu, 6 Jul 2023 17:25:07 +0000 (UTC)
Received: from localhost (localhost [127.0.0.1])
by smtp1.osuosl.org (Postfix) with ESMTP id EAE8C822AD
for <bitcoin-dev@lists.linuxfoundation.org>;
Thu, 6 Jul 2023 17:25:06 +0000 (UTC)
DKIM-Filter: OpenDKIM Filter v2.11.0 smtp1.osuosl.org EAE8C822AD
Authentication-Results: smtp1.osuosl.org; dkim=pass (2048-bit key,
unprotected) header.d=achow101.com header.i=@achow101.com header.a=rsa-sha256
header.s=protonmail header.b=Rd5cyTI1
X-Virus-Scanned: amavisd-new at osuosl.org
X-Spam-Flag: NO
X-Spam-Score: -2.102
X-Spam-Level:
X-Spam-Status: No, score=-2.102 tagged_above=-999 required=5
tests=[BAYES_00=-1.9, DKIM_SIGNED=0.1, DKIM_VALID=-0.1,
DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, SPF_HELO_PASS=-0.001,
SPF_PASS=-0.001] autolearn=ham autolearn_force=no
Received: from smtp1.osuosl.org ([127.0.0.1])
by localhost (smtp1.osuosl.org [127.0.0.1]) (amavisd-new, port 10024)
with ESMTP id 1_qSlkYNF-oq
for <bitcoin-dev@lists.linuxfoundation.org>;
Thu, 6 Jul 2023 17:25:05 +0000 (UTC)
X-Greylist: from auto-whitelisted by SQLgrey-1.8.0
DKIM-Filter: OpenDKIM Filter v2.11.0 smtp1.osuosl.org E7482821F6
Received: from mail-41104.protonmail.ch (mail-41104.protonmail.ch
[185.70.41.104])
by smtp1.osuosl.org (Postfix) with ESMTPS id E7482821F6
for <bitcoin-dev@lists.linuxfoundation.org>;
Thu, 6 Jul 2023 17:25:04 +0000 (UTC)
Date: Thu, 06 Jul 2023 17:24:47 +0000
Authentication-Results: mail-41104.protonmail.ch;
dkim=pass (2048-bit key) header.d=achow101.com header.i=@achow101.com
header.b="Rd5cyTI1"
DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=achow101.com;
s=protonmail; t=1688664292; x=1688923492;
bh=eUF1PeaeEhL/P0huDQLJzdFixx7oIWTE1PEVHoxxISs=;
h=Date:To:From:Subject:Message-ID:In-Reply-To:References:
Feedback-ID:From:To:Cc:Date:Subject:Reply-To:Feedback-ID:
Message-ID:BIMI-Selector;
b=Rd5cyTI1DIEAN8SHnKwuCsXF7jEEDB1PUGcRMVcG59+kolf8BO2IfcXaFcy8eICfh
HaAPU4JdDX+c62OjE2VhJ6VC5sxxR5fpB5qjwSBuZQwZcII0Siqme5AXzN+/Gm8bQ9
0cUw9v/raWjEtuUJ+8jt+v1joloN5BIcpfTs/CppGR+wa6E92dPoLYVqo2DKkoHaNZ
hm6ltta7yHskgbDR0FB2HSx4TCFqrVtsN/wNx7C7VZsIjP0aM8QjNNBea1PvblbZIA
Zgb9w2XXOjuusQ2tcU4CXleDGDQlsgHX9DKds9dJ/2X7BWyWpnkebbTI+Rin6J04TY
09mqS9D1mCrTg==
To: bitcoin-dev@lists.linuxfoundation.org
From: Andrew Chow <lists@achow101.com>
Message-ID: <67c37967-ba7d-eabe-01e7-c5a0f9ca7da8@achow101.com>
In-Reply-To: <Ga2AELVMhRn2JlAC1-85LivVhcBhXzsf5ypHXMt_lg9RpwKTxeRxIRr8g8UHUihvxIVNKua6FIGRCjkt4CuNcDtZy2MetpOucpZYoKPW5sw=@protonmail.com>
References: <Ga2AELVMhRn2JlAC1-85LivVhcBhXzsf5ypHXMt_lg9RpwKTxeRxIRr8g8UHUihvxIVNKua6FIGRCjkt4CuNcDtZy2MetpOucpZYoKPW5sw=@protonmail.com>
Feedback-ID: 53660394:user:proton
MIME-Version: 1.0
Content-Type: text/plain; charset=utf-8
Content-Transfer-Encoding: quoted-printable
X-Mailman-Approved-At: Thu, 06 Jul 2023 18:26:04 +0000
Subject: Re: [bitcoin-dev] Denial of Service using Package Relay
X-BeenThere: bitcoin-dev@lists.linuxfoundation.org
X-Mailman-Version: 2.1.15
Precedence: list
List-Id: Bitcoin Protocol Discussion <bitcoin-dev.lists.linuxfoundation.org>
List-Unsubscribe: <https://lists.linuxfoundation.org/mailman/options/bitcoin-dev>,
<mailto:bitcoin-dev-request@lists.linuxfoundation.org?subject=unsubscribe>
List-Archive: <http://lists.linuxfoundation.org/pipermail/bitcoin-dev/>
List-Post: <mailto:bitcoin-dev@lists.linuxfoundation.org>
List-Help: <mailto:bitcoin-dev-request@lists.linuxfoundation.org?subject=help>
List-Subscribe: <https://lists.linuxfoundation.org/mailman/listinfo/bitcoin-dev>,
<mailto:bitcoin-dev-request@lists.linuxfoundation.org?subject=subscribe>
X-List-Received-Date: Thu, 06 Jul 2023 17:25:07 -0000
On 07/06/2023 12:22 PM, alicexbt via bitcoin-dev wrote:
> 1) Register input in A
> 2) Double spend same input with zero fee to your own address
> 3) Register unconfirmed UTXO from 2 in B
Why would unconfirmed inputs be accepted in a coinjoin? That seems=20
unsafe, regardless of package relay. The sender of the unconfirmed=20
transaction can already replace it thereby pinning or otherwise=20
invalidating the coinjoin, it doesn't need package relay.
Furthermore, the coordinator B shouldn't accept the unconfirmed UTXO=20
from 2 because it doesn't even know about that unconfirmed transaction.=20
It has zero fee, so it's not going to be relayed.
Conceivably a similar attack can already be done by simply registering=20
the same UTXO with multiple coordinators anyways. This doesn't require=20
package relay either.
***
Package relay should help coinjoins since any one of the participants=20
can rebroadcast the coinjoin with a further CPFP if the coinjoin is=20
below the minimum relay fee. Some of the upcoming package RBF proposals=20
should also help by allowing other child transactions in the package to=20
RBF the entire thing, thereby resolving the need to have everyone=20
re-sign the coinjoin in order to RBF.
Andrew
|