Missing access control when linking trackers to campaigns

Summary

HackerOne community member Ahmed Ghadban (DarkyOS) has reported a missing access control check when linking trackers to campaigns through the campaign-trackers.php script of Revive Adserver 6.0.6 and earlier. A low‑privileged user could link their trackers to campaigns owned by other managers on the same instance, resulting in inconsistent ownership relationships.

Ownership validation has been added to ensure that campaigns can only be linked to trackers owned by the same advertiser.