Re: Handling of unverified data and media

Roman Shpount <[email protected]>
Newsgroups gmane.ietf.mmusic
Message-ID <CAD5OKxvwV38dJXR3mYSiQEnNoX3X7nfMY2hBe1S4kxj7h6WZWA@mail.gmail.com>
Peter,

Any comments on the ICE Lite scenario? I did see it in the wild.

Regards,

_____________
Roman Shpount

On Thu, Mar 30, 2017 at 9:11 PM, Roman Shpount <[email protected]> wrote:

> Peter,
>
> What about ICE lite? If ICE lite sends an offer to WebRTC end point, it
> can get DTLS ClientHello before it got the answer response from the WebRTC
> end point. Since ICE lite client does not send ICE requests before sending
> data, it will respond with ServerHello and establish the connection. At
> this point data can be sent to it before the answer arrives and fingerprint
> can be verified.
>
> I think the right answer to this situation is not to send ServerHello
> until answer and fingerprint is received. ClientHello should be buffered
> and only handled when answer is received.
>
> Regards,
>
> _____________
> Roman Shpount
>
> On Thu, Mar 30, 2017 at 7:40 PM, Peter Thatcher <[email protected]>
> wrote:
>
>> Bernard, you are right that this is possible with ORTC, even though I
>> think it's impossible with WebRTC.  But that's clearly out of scope for the
>> MMUSIC WG.  Perhaps the right forum to discuss Cullen's 1-800-fedex use
>> case is in the context of ORTC (or WebRTC NV).
>>
>> On Thu, Mar 30, 2017 at 3:50 PM Martin Thomson <[email protected]>
>> wrote:
>>
>>> These both sound like legitimate cases where ICE can precede
>>> signaling.  I would recommend that the W3C think carefully about
>>> whether they might like to accept (potentially) invalid data before we
>>> spend a whole lot more time on the issue.
>>>
>>> On 30 March 2017 at 17:11, Bernard Aboba <[email protected]>
>>> wrote:
>>> > The unverified media scenarios seem to depend on ICE connectivity being
>>> > bi-directionally enabled so as to permit the DTLS negotiation to
>>> proceed in
>>> > advance of remote fingerprint arrival. If ICE candidates are signaled
>>> > separately from the DTLS fingerprint exchange it might be feasible,
>>> such as
>>> > in ORTC signaling where the ICE parameters are exchanged before the
>>> > DtlsParameters.
>>> >
>>> > At the last WebRTC interim a scenario involving PRANSWER and Trickle
>>> ICE was
>>> > presented. In the scenario, the PRANSWER included a fingerprint, but
>>> > possibly one which did not match the certificate provided in DTLS
>>> unlike the
>>> > final answer. I do not see how this could work but perhaps I am missing
>>> > something.
>>> >
>>> > On Mar 30, 2017, at 14:14, Peter Thatcher <[email protected]>
>>> wrote:
>>> >
>>> > We have a mailing list discussion (here), a bug
>>> > (https://github.com/w3c/webrtc-pc/issues/849) and a PR
>>> > (https://github.com/w3c/webrtc-pc/pull/1026#issuecomment-279238215)
>>> about
>>> > this.  I've copied the following comments to the latter two, so I'm
>>> adding
>>> > them here as well.
>>> >
>>> > TL;DR: I don't think unverified media is compatible with ICE+DTLS.
>>> Here is
>>> > why (you can go see the bug, too):
>>> >
>>> > You can receive DTLS from the remote side before receiving the remote
>>> > description (and thus fingerprint). This happens if the remote side
>>> sends an
>>> > ICE connectivity check and the local side sends a response and then the
>>> > remote side sends a DTLS packet.
>>> >
>>> > You cannot send DTLS from the local side before receiving the remote
>>> > description (and thus fingerprint). This is because you can't send an
>>> ICE
>>> > connectivity check until you have the remote ICE ufrag and pwd, and
>>> thus
>>> > can't get an ICE connectivity check response, and thus can't send
>>> DTLS. This
>>> > is because you can't send anything other than ICE until you get an ICE
>>> > connectivity check response.
>>> >
>>> > Since you can't send DTLS, you can't complete the handshake, and thus
>>> can't
>>> > extract the SRTP key.
>>> >
>>> >
>>> > Maybe I'm missing something, but I think this is impossible.
>>> >
>>> > On Sat, Mar 25, 2017 at 1:12 PM Cullen Jennings <[email protected]> wrote:
>>> >>
>>> >>
>>> >> On Mar 13, 2017, at 3:44 PM, Christer Holmberg
>>> >> <[email protected]> wrote:
>>> >>
>>> >> My question is: is this something that’s causing problems in real
>>> >> deployments, and requires a change in the standard?
>>> >>
>>> >>
>>> >> 1-800 go fedex. See webrtc requirements documents from many years ago.
>>> >> _______________________________________________
>>> >> mmusic mailing list
>>> >> [email protected]
>>> >> https://www.ietf.org/mailman/listinfo/mmusic
>>> >
>>> > _______________________________________________
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>>> >
>>> >
>>> > _______________________________________________
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>>> > https://www.ietf.org/mailman/listinfo/mmusic
>>> >
>>>
>>
>> _______________________________________________
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>>
>>
>

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