Why are chinese songs permitted to use tunes of our music artists?

Every now and then you'd hear M2M's song, or Mariah's or whoever there is there to know, but then you'd start hearing Chinese, mandarin lyrics singing behind their trademarks. How do they do that. Are they granted copyright use? (I mean it's weird, these famous Chinese songs getting all famous over the chinese society with M2M's or whoever there is' trademarked song.)