GPLv2 clause 6

“So, let’s suppose you (Bob) receive a program under the
GPLv2 from the original author (licensor, called Alice), and pass
it on unmodified to a third party, Charles. Clause 1 of the GPL
applies, because it is verbatim. You just need to give Charles a
copy of the license, and Charles receives a license from Alice
automatically. There is in my reading no license, no relation
whatsoever between you and Charles. Now if Charles distributes the
program, the only license he could violate is Alice’s, and it
is Alice who would need to enforce any violation.

“This is actually how it works, too — suppose Alice wrote
a part of the Linux kernel, she grants a license to any recipient
(Charles) even though there are second parties involved (Bob);
Alice can enjoin Charles to satisfy the requirements of the
license.”

Complete
Story