[Webkit-unassigned] [Bug 180842] srflx and relay ICE candidates lack raddr (rel-addr) and rport (rel-port) attributes if getUserMedia access has not been granted

[bugzilla-daemon at webkit.org]

https://bugs.webkit.org/show_bug.cgi?id=180842

--- Comment #2 from Mark Roberts <mroberts at twilio.com> ---
Hi Youenn,

Thanks for the quick response.

> host candidates are filtered out for privacy reasons

Yes, this is what I expected. I think I remember you mentioning this at Kranky Geek. IMO, there should be no problem there.

> and so are raddr/rport information on reflexive and relay candidates.

However, this seems to be the source of the interop problem with Firefox. If I write a little function to patch these up before sending them out:

  function patchIceCandidate(candidate) {
    var candidateStr = candidate.candidate;                                          
    var type = candidateStr.match(/typ ([^ ]*)/)[1];                                 
    switch (type) {                                                                  
      case 'srflx':                                                                  
      case 'prflx':                                                                  
      case 'relay':                                                                  
        var raddr = candidateStr.match(/raddr ([^ ]*)/);                             
        var rport = candidateStr.match(/rport ([^ ]*)/);                             
        if (!raddr || !rport) {                                                      
          console.warn(type + ' ICE candidate lacks raddr and/or rport: ' + candidateStr);
          if (!raddr) {                                                              
            candidateStr = candidateStr.replace('generation', 'raddr 0.0.0.0 generation');
          }                                                                          
          if (!rport) {                                                              
            candidateStr = candidateStr.replace('generation', 'rport 0 generation');
          }                                                                          
          candidate = new RTCIceCandidate({                                          
            candidate: candidateStr,                                                 
            sdpMid: candidate.sdpMid,                                                
            sdpMLineIndex: candidate.sdpMLineIndex                                   
          });                                                                        
        }                                                                            
      default:                                                                       
        break;                                                                       
    }
    return candidate;
  }

Then there are no more ICE failures in Firefox.

I can understand filtering the raddr and rport attributes if they include sensitive information; however, I suppose Firefox may be a bit stricter in its parsing of ICE candidates (since technically raddr and rport are required). Strangely, though, it doesn't raise an error. I will probably open an issue with them next.

Also, I can understand filtering the raddr and rport attributes if they includes sensitive information; however, in the test I shared, I see they are just set to 0.0.0.0 and 0 _if `getUserMedia` was previously called_ (note that it doesn't matter if the resulting MediaStreamTracks are added to any RTCPeerConnections or not). So maybe instead of filtering, Safari could use these dummy values?

Thanks!
Mark

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