From: "H. Peter Anvin" <hpa@zytor.com>
To: Kees Cook <keescook@chromium.org>
Cc: Stephen Hemminger <stephen@networkplumber.org>,
LKML <linux-kernel@vger.kernel.org>,
Rob Landley <rob@landley.net>,
"David S. Miller" <davem@davemloft.net>,
Alexey Kuznetsov <kuznet@ms2.inr.ac.ru>,
James Morris <jmorris@namei.org>,
Hideaki YOSHIFUJI <yoshfuji@linux-ipv6.org>,
Patrick McHardy <kaber@trash.net>,
Eric Dumazet <edumazet@google.com>,
Neil Horman <nhorman@tuxdriver.com>,
Yuchung Cheng <ycheng@google.com>,
Shan Wei <davidshan@tencent.com>,
"linux-doc@vger.kernel.org" <linux-doc@vger.kernel.org>,
netdev@vger.kernel.org, Willy Tarreau <w@1wt.eu>
Subject: Re: [PATCH] tcp: sysctl to disable TCP simultaneous connect
Date: Thu, 07 Feb 2013 11:29:08 -0800 [thread overview]
Message-ID: <51140084.3080902@zytor.com> (raw)
In-Reply-To: <CAGXu5jJiupzommJYPEYQnk-4i9FUKai0NcPnihLN-QpWV64jtQ@mail.gmail.com>
On 02/07/2013 10:44 AM, Kees Cook wrote:
>>
>> This patch probably also breaks TCP STUNT that is used by some applications for NAT
>> traversal.
>
> The patch would not break it -- it defaults the sysctl to staying enabled.
>
> If you mean the documentation should be updated, sure, that's easy to do.
>
> David: I know you aren't a fan of this patch, but I'd like to try to
> convince you. :) This leaves the feature enabled and add a toggle for
> systems (like Chrome OS) that don't want to risk this DoS at all.
> There are so very many other toggle, I don't see why this one would be
> a problem to add.
>
It is not just STUNT, but in NAT-less configurations behind stateful
firewalls (which is expected to be the norm for IPv6), TCP rendezvous
via crossed SYN is a very effective way to establish peer-to-peer
connections.
-hpa
next prev parent reply other threads:[~2013-02-07 19:31 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-02-07 17:52 [PATCH] tcp: sysctl to disable TCP simultaneous connect Kees Cook
2013-02-07 18:15 ` David Miller
2013-02-07 18:39 ` Stephen Hemminger
2013-02-07 18:44 ` Kees Cook
2013-02-07 19:29 ` H. Peter Anvin [this message]
2013-02-07 19:29 ` David Miller
2013-02-15 5:30 ` Eric W. Biederman
2013-02-15 6:41 ` Kees Cook
2013-02-15 7:10 ` Eric W. Biederman
2013-02-15 7:55 ` Willy Tarreau
2013-02-15 10:31 ` Eric W. Biederman
2013-02-15 10:47 ` Willy Tarreau
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