1511941 - privacy.resistfingerprinting performance API spoofing breaks vimeo.com

Status: NEW

(Core :: DOM: Core & HTML, defect, P2)

Description

[Kestrel]

Console error:
> TypeError: t[0] is undefined; can't access its "startTime" property

Code responsible:

d=function() {
  var e = window.performance;
  if (!e)
    return 0;
  if (window.PerformanceNavigationTiming) {
    var t = e.getEntriesByType("navigation");
    return t[0].startTime;
  }
  return e.timing.navigationStart;
}

Comment 1

[Tom Ritter [:tjr] (needinfo for responses to sec-[approval/ratings/advisories])]

Oh, this should be easy; we shouldn't expose PerformanceNavigationTiming if we don't support it. We should also check Resource Timing.

Comment 2

[Kestrel]

Vimeo have fixed it at their end by adding an extra check:

> return t && t.length ? t[0].startTime : 0;

Comment 3

[Ethan Tseng [:ethan]]

(In reply to Kestrel from comment #2)
> Vimeo have fixed it at their end by adding an extra check: 
> > return t && t.length ? t[0].startTime : 0;

Does this mean we can close this bug as resolved worksforme?

Comment 4

[Tom Ritter [:tjr] (needinfo for responses to sec-[approval/ratings/advisories])]

No, I think we should do what I specify in Comment 1 to be spec-compliant.

Comment 5

[Ethan Tseng [:ethan]]

(In reply to Tom Ritter [:tjr] from comment #4)
> No, I think we should do what I specify in Comment 1 to be spec-compliant.

Thanks for clarification.