/admin/listclients with URL authentication returns 403 Forbidden Mountpoint in use

[TheRealMattLear]

Normally the /admin/listclients?mountpoint=/stream URL is accessible by authenticating with the <source-password> (when not using Mountpoint Authentication. However when specifying <authentication type="url"> with the stream_auth option the end-point returns 403 Forbidden with "Mountpoint in use".

A similar issue has been created 3 years ago at xiph.org and i've logged an issue directly at Icecast-Server GH.

This end-point is specifically used by RadioCaster (possibly other encoders) to present the listeners on the connected mount.

In our testing:

• The header icecast-auth-user: 1 is purposely always returned regardless of provided username/password
• Source client encoder connects and broadcasts successfully
• Authentication with is always successful, even when returning icecast-auth-user: 0
• On connect to /admin/listclients we can see through nginx logs and wireshark that the endpoint is being hit successfully and the correct header being sent back to icecast service

Example configuration where "Mountpoint in use" error is presented (auth.php always returning header icecast-auth-user: 1), even if using authentication of source:source-password

<icecast>
    <limits>
        ...
    </limits>

    <authentication>
        <source-password>source-password</source-password>
        <admin-user>admin</admin-user>
        <admin-password>admin-password</admin-password>
    </authentication>
    <mount>
      <mount-name>/stream</mount-name>
      <charset>UTF-8</charset>
      <bitrate>128</bitrate>
      <authentication type="url">
        <option name="stream_auth" value="http://localhost/auth.php"/>
      </authentication>
    </mount>
    ...
</icecast>

Example configuration that works successfully with source:source-password

<icecast>
    <limits>
        ...
    </limits>

    <authentication>
        <source-password>source-password</source-password>
        <admin-user>admin</admin-user>
        <admin-password>admin-password</admin-password>
    </authentication>
    <mount>
      <mount-name>/stream</mount-name>
      <charset>UTF-8</charset>
      <bitrate>128</bitrate>
    </mount>
    ...
</icecast>