Re: [secdir] SecDir Review of draft-ietf-rtcweb-stun-consent-freshness-14

Martin Thomson <> Tue, 09 June 2015 17:37 UTC

Return-Path: <>
Received: from localhost ( []) by (Postfix) with ESMTP id 8892F1B2DA4; Tue, 9 Jun 2015 10:37:57 -0700 (PDT)
X-Virus-Scanned: amavisd-new at
X-Spam-Flag: NO
X-Spam-Score: -0.101
X-Spam-Status: No, score=-0.101 tagged_above=-999 required=5 tests=[BAYES_40=-0.001, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, FREEMAIL_FROM=0.001, SPF_PASS=-0.001] autolearn=ham
Received: from ([]) by localhost ( []) (amavisd-new, port 10024) with ESMTP id YxXfRidX9_IC; Tue, 9 Jun 2015 10:37:51 -0700 (PDT)
Received: from ( [IPv6:2607:f8b0:4002:c07::229]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by (Postfix) with ESMTPS id 3A29E1B2DB6; Tue, 9 Jun 2015 10:37:51 -0700 (PDT)
Received: by yked142 with SMTP id d142so11545521yke.3; Tue, 09 Jun 2015 10:37:50 -0700 (PDT)
DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed;; s=20120113; h=mime-version:in-reply-to:references:date:message-id:subject:from:to :cc:content-type:content-transfer-encoding; bh=RjkriLBUV9/2RhwjFvaTSNz2mu/C6+a7H7LGUiiX9J4=; b=ei89l81/MVGqld5YxOyyx8TAA7BPcMwATGuEFcRjsXbCOaAAYqzEWL/BwRmherl5Ui 0HQWalGEsPeUAAnrXqfq8j4Ky2UIb+y57IChEG0Zdpqw8Bss1uqKkm+OiHpTtx4HgDaO 2SAOWfLgcbSkYmNeAKN+EaQtjvRW2ya1bx/7ZBueMxN1VnfC3DPGwTfYfyVZDIdYvV6q ZX5R7JybgZ9zfqchZlHyiqVHa2EvbzNKhszGRJzPM+AFvaqyhR5/1bW5ZQQvdBG3KjwL A7Qx4vYjf4aRh4tG90KqQDCR7i2K9O/2XzFksULiXAN9pNEx/7RrHV22Hwh8GWxqpr7m /E5A==
MIME-Version: 1.0
X-Received: by with SMTP id g126mr26657953ykc.98.1433871469892; Tue, 09 Jun 2015 10:37:49 -0700 (PDT)
Received: by with HTTP; Tue, 9 Jun 2015 10:37:49 -0700 (PDT)
In-Reply-To: <>
References: <>
Date: Tue, 9 Jun 2015 10:37:49 -0700
Message-ID: <>
From: Martin Thomson <>
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: quoted-printable
Archived-At: <>
Cc:, The IESG <>, "" <>
Subject: Re: [secdir] SecDir Review of draft-ietf-rtcweb-stun-consent-freshness-14
X-Mailman-Version: 2.1.15
Precedence: list
List-Id: Security Area Directorate <>
List-Unsubscribe: <>, <>
List-Archive: <>
List-Post: <>
List-Help: <>
List-Subscribe: <>, <>
X-List-Received-Date: Tue, 09 Jun 2015 17:37:57 -0000

On 9 June 2015 at 06:50,  <> wrote:
> 1)      Will misbehaving or malicious endpoints obey this? If not, what’s
> the point? If only a few polite endpoints go to the trouble of obtaining
> consent to send, I don’t see how this will solve anything.

Good actors will respect this, and that has proven sufficient to stop
congestion collapse in TCP.

ICE is already the foundation of real-time communications.  This just
patches a hole.

This will be implemented in web browsers, which means that they cannot
be used as a (sustained) DoS platform.

> 2)      Section 5.1 says “An endpoint MUST NOT send data other than the
> messages used to establish consent unless the receiving endpoint has
> consented to receive data.” This seems to be a long way from the present
> reality. How many applications implement this requirement? Or will this
> feature somehow be built into the OS?

This is already the case for all real-time implementations today.  And
it will - in effect - be part of the platform of the web when it is
made part of a browser.

> 3)      The document says that “Consent expires after 30 seconds.” And
> “Implementations SHOULD set a default interval of 5 seconds” for
> retransmitting STUN binding requests (requests for consent). If I understand
> this correctly, every pair of endpoints with an active connection will now
> exchange STUN binding request and response pairs in each direction every
> five seconds. That works out to about one packet per second transit for
> every connection. That seems like a lot of overhead. Is the benefit
> adequate?

We're talking real-time communications, where 50 packets per second
each way is the baseline.  This is a negligible increase.