Israelinsider.com says Obama’s campaign tried to shop it around and Maariv was the only one who bit.
Given that all sorts of public figures in Israel are expressing outrage over the incident, and the only source I’ve seen for the claim that Maariv had prior permission to publish the note’s contents is Maariv itself, and that Maariv itself also says it got the original note from a “religious student”, I conclude that Maariv had no permission to publish the note at the time it decided to do so. Perhaps the timetable was that Maariv announced, either publicly or just to Obama’s staff, that they were about to the publish the contents of the note, and Obama and his staff responded by making the contents public and authorizing any media outlet to publish it, in order to prevent Maariv from profiting from a “scoop”. Nobody would be expressing outrage at Maariv (and in at least one case, demanding a criminal inquiry), if Obama has initiated the publication by offering the contents of the note to the media at large accompanied by permission to publish (in the latter case, Obama would more likely be the target of outrage, and properly so).