https://www.forbes.com/sites/danielfisher/2017/01/30/does-the-constitution-protect-non-citizens-judges-say-yes/?sh=c8b4d9f4f1de

The same way it applied to enemy combatants held at the U.S. base in Guantanamo Bay in a 2008 U.S. Supreme Court decision, *Boumediene v. Bush, *which held that the basic right of habeas corpus to challenge illegal detentions extends even to non-citizens on foreign territory.

Unless otherwise specified, the rights granted in the US constitution apply to all people of the world regardless of where they are.

If corporations are people as defined by citizens united, then these protections apply to foreign companies also.