Re: [rtcweb] Resolving RTP/SDES question in Paris

Iñaki Baz Castillo <ibc@aliax.net> Sat, 17 March 2012 16:24 UTC

Return-Path: <ibc@aliax.net>
X-Original-To: rtcweb@ietfa.amsl.com
Delivered-To: rtcweb@ietfa.amsl.com
Received: from localhost (localhost [127.0.0.1]) by ietfa.amsl.com (Postfix) with ESMTP id 9FFFA21F857A for <rtcweb@ietfa.amsl.com>; Sat, 17 Mar 2012 09:24:37 -0700 (PDT)
X-Virus-Scanned: amavisd-new at amsl.com
X-Spam-Flag: NO
X-Spam-Score: -2.613
X-Spam-Level:
X-Spam-Status: No, score=-2.613 tagged_above=-999 required=5 tests=[AWL=0.064, BAYES_00=-2.599, FM_FORGED_GMAIL=0.622, MIME_8BIT_HEADER=0.3, RCVD_IN_DNSWL_LOW=-1]
Received: from mail.ietf.org ([12.22.58.30]) by localhost (ietfa.amsl.com [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id iUAD1l1pJjB2 for <rtcweb@ietfa.amsl.com>; Sat, 17 Mar 2012 09:24:37 -0700 (PDT)
Received: from mail-vx0-f172.google.com (mail-vx0-f172.google.com [209.85.220.172]) by ietfa.amsl.com (Postfix) with ESMTP id 03AE921F856D for <rtcweb@ietf.org>; Sat, 17 Mar 2012 09:24:36 -0700 (PDT)
Received: by vcbfk13 with SMTP id fk13so6327662vcb.31 for <rtcweb@ietf.org>; Sat, 17 Mar 2012 09:24:36 -0700 (PDT)
X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20120113; h=mime-version:in-reply-to:references:from:date:message-id:subject:to :cc:content-type:content-transfer-encoding:x-gm-message-state; bh=/kyuE83CdHk5EOjdKOGTAa312APDns439LI3G5BjEng=; b=aRn9E2c6FvNhgwR6rNPhw0dBGqQMGfwT3Jm+6vloCfg69MpS3yONZPIbHTI5Z0flIA RdTjf6JQYCAYNADVNpMTURrSjret1tNF2380lOPVsP+KzickoYzqL6OWg0LlRNk+X22U lz0tfPopFrSQp1tDSDGL8r86ibik/XDhPQpTm0GAI5BWi8FnMFE183I4xxbspgRqubgs nuMfYrCtAg4lRPiBwCb4pvrInPe0aNQIVPnUh2yqKGqnzkCL/fkW3UqJ3ID/v+XMyYUi bAc1n4hatlSbXImuqFBeT7J+6JRi67nLbijeosWHVSUJOBoVTGr7LoqYc1icC+2vph1h cNqQ==
Received: by 10.220.116.20 with SMTP id k20mr2288833vcq.54.1332001476447; Sat, 17 Mar 2012 09:24:36 -0700 (PDT)
MIME-Version: 1.0
Received: by 10.52.165.162 with HTTP; Sat, 17 Mar 2012 09:24:16 -0700 (PDT)
In-Reply-To: <CAD5OKxvtOAxMBx6xDnyfTnEq76oDEm6uj1xL6wGjjrtKUAHy3g@mail.gmail.com>
References: <4F4759DC.7060303@ericsson.com> <387F9047F55E8C42850AD6B3A7A03C6C0E1FEB69@inba-mail01.sonusnet.com> <CALiegfnkYVEpmPV-zSL_4wOY-HiFZN-qJCQCiioaS=5NaqhLZw@mail.gmail.com> <CAD5OKxvtOAxMBx6xDnyfTnEq76oDEm6uj1xL6wGjjrtKUAHy3g@mail.gmail.com>
From: Iñaki Baz Castillo <ibc@aliax.net>
Date: Sat, 17 Mar 2012 17:24:16 +0100
Message-ID: <CALiegf=D8Zg+i2hr77n57SDc6Ji_Wvs=uBZsWR5KHWHYSpGx+A@mail.gmail.com>
To: Roman Shpount <roman@telurix.com>
Content-Type: text/plain; charset="UTF-8"
Content-Transfer-Encoding: quoted-printable
X-Gm-Message-State: ALoCoQn/LqnEQ077FjhigqeO5Fy59XUvmGN8oH/x8pknH3Rzjl2mcE+iFpdokGS3KfT8e+vWVQvs
Cc: "rtcweb@ietf.org" <rtcweb@ietf.org>
Subject: Re: [rtcweb] Resolving RTP/SDES question in Paris
X-BeenThere: rtcweb@ietf.org
X-Mailman-Version: 2.1.12
Precedence: list
List-Id: Real-Time Communication in WEB-browsers working group list <rtcweb.ietf.org>
List-Unsubscribe: <https://www.ietf.org/mailman/options/rtcweb>, <mailto:rtcweb-request@ietf.org?subject=unsubscribe>
List-Archive: <http://www.ietf.org/mail-archive/web/rtcweb>
List-Post: <mailto:rtcweb@ietf.org>
List-Help: <mailto:rtcweb-request@ietf.org?subject=help>
List-Subscribe: <https://www.ietf.org/mailman/listinfo/rtcweb>, <mailto:rtcweb-request@ietf.org?subject=subscribe>
X-List-Received-Date: Sat, 17 Mar 2012 16:24:37 -0000

2012/3/17 Roman Shpount <roman@telurix.com>:
> Furthermore comparison between HTTP/HTTPS and RTP/SRTP in not entirely
> appropriate. HTTPS communications are reasonably secure. SRTP calls, unless
> we make identity management a requirement for WebRTC, are only giving people
> a false sense of security. The fact that browser uses SRTP does not, in any
> way, imply that the communication is secure. If the key was delivered over
> HTTP, anybody intercepting your IP traffic can listen to it. If we are
> dealing with the server based attack then all hell breaks loose. So, unless
> we requiring that only connections are over DTLS-SRTP using an SDP signed by
> a verified remote party are allowed, we allow unsecure connections.

Well, I just said that in order to get secure communications WebRTC
has to mandate SRTP and disallow plain RTP. I didn't enter in details
but of course I agree with you. However to accomplish with your
points, my statements (SRTP is a MUST and RTP should not be allowed)
are valid.


> We need
> to show an appropriate warning for all of them, and warning RTP vs SDES-SRTP
> vs unsigned DTLS-SRTP should not be very different. It should say "You are
> trying to communicate over unsecure peer--to-peer channel with an unknown
> party. Continue?" There is no, "you are trying to use slightly more secure
> channel. Is this ok?".

I don't entirely agree. In my example (the airport with open WiFi) the
signaling could be secured via HTTPS and the media secured with
SDES-SRTP. In this way other users in same open WiFi network cannot
monitor the signaling so they cannot get the SDES key, and therefore
they cannot monitor the SDES-SRTP stream. This is really better than
allowing plain RTP in an open WiFi network, am I wrong?


Regards.


-- 
Iñaki Baz Castillo
<ibc@aliax.net>