At present, songs purchased in the iTunes store are only "borrowed" under a licence - something that has frustrated iTunes users for years.
Willis has reportedly downloaded thousands of dollars worth of songs and doesn't want them reverting back to Apple in the event of his death.
The 57-year-old actor is looking into legal methods to challenge the Cupertino small print, including setting up a family trust to keep the music safe for his three daughters.
Alternatively he can take Apple to court in order to fight the rules on ownership of downloaded content.
If he's successful then it could have repercussions for the millions of iTunes users worldwide. Although, even for Bruce Willis, Apple might prove too powerful an opponent.
The company currently has the power to freeze an iTunes account if it suspects the user of illegally sharing music.
And indefinitely renting content isn't a practice exclusive to Apple - Amazon has a similar position with regards to ebooks bought for the Kindle.