1349373 - [EME] MediaKeys allows the creation of unsupported session types

Status: RESOLVED FIXED

(Core :: Audio/Video: Playback, defect)

Description

[joeyparrish]

User Agent: Mozilla/5.0 (X11; CrOS x86_64 9202.53.0) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/57.0.2987.112 Safari/537.36

Steps to reproduce:

1. Open https://storage.googleapis.com/shaka-demo-assets/_bugs/persistent-session-support/index.html
2. Accept any EME-related prompts
3. Open the JS console
4. Look at the report of persistent session support

If persistent sessions are present in the config from MediaKeySystemAccess, it should be possible to create a session of type 'persistent-license'.  If not, it should not be possible to create one.

Firefox reports that these sessions are not supported, but allows the application to create one anyway.  This would cause problems for applications that do not check getConfiguration(), but instead rely on the creation of a session.  Shaka Player was using this strategy in our support probe to work around an Edge bug in which getConfiguration() doesn't report sessionTypes at all.


Actual results:

Results from Firefox 51 on Windows 10:

support {
  "org.w3.clearkey": {
    "persistentSessionInConfig": true,
    "persistentSessionCreated": true
  },
  "com.widevine.alpha": {
    "persistentSessionInConfig": false,
    "persistentSessionCreated": true
  },
  "com.adobe.primetime": {
    "persistentSessionInConfig": false,
    "persistentSessionCreated": true
  }
}

Note that for Widevine & PrimeTime, createSession('persistent-license') works even though 'persistent-license' is not in sessionTypes from getConfiguration().


Expected results:

Results from Chrome 56.0.2924 on Windows 10 (persistent-license not supported):
support {
  "org.w3.clearkey": {
    "persistentSessionInConfig": false,
    "persistentSessionCreated": false
  },
  "com.widevine.alpha": {
    "persistentSessionInConfig": false,
    "persistentSessionCreated": false
  }
}

Results from ChromeOS 57.0.2987.112 (persistent-license supported):
support {
  "org.w3.clearkey": {
    "persistentSessionInConfig": false,
    "persistentSessionCreated": false
  },
  "com.widevine.alpha": {
    "persistentSessionInConfig": true,
    "persistentSessionCreated": true
  }
}

Comment 1

[Anthony Jones (:ajones, :kentuckyfriedtakahe, :k17e)]

Chris - is this on your radar?

Comment 2

[Chris Pearce [:cpearce (Not reading bugmail)]]

Joey: I'm Firefx Beta 54, I'm getting:

support {
  "org.w3.clearkey": {
    "persistentSessionInConfig": false,
    "persistentSessionCreated": false
  },
  "com.widevine.alpha": {
    "persistentSessionInConfig": false,
    "persistentSessionCreated": false
  }
}  index.html:54:3

This looks fixed to me, can you confirm?

Comment 3

[joeyparrish]

Yup, looks fixed to me.  I tested in Firefox 53 on Linux and got the correct results.  Thanks!

Comment 4

[Chris Pearce [:cpearce (Not reading bugmail)]]

Sweet!